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PATRIZIA MARIA TARUGI
COLLABORATORE DI RICERCA
Dipartimento di Scienze della Vita sede ex-Scienze Biomediche
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Pubblicazioni
2023
- Clinical Approach in the Management of Paediatric Patients with Familial Hypercholesterolemia: A National Survey Conducted by the LIPIGEN Paediatric Group
[Articolo su rivista]
Pederiva, Cristina; Gazzotti, Marta; Arca, Marcello; Averna, Maurizio; Banderali, Giuseppe; Biasucci, Giacomo; Brambilla, Marta; Buonuomo, Paola Sabrina; Calabrò, Paolo; Cipollone, Francesco; Citroni, Nadia; D'Addato, Sergio; Del Ben, Maria; Genovesi, Simonetta; Guardamagna, Ornella; Iannuzzo, Gabriella; Iughetti, Lorenzo; Mandraffino, Giuseppe; Maroni, Lorenzo; Mombelli, Giuliana; Muntoni, Sandro; Nascimbeni, Fabio; Passaro, Angelina; Pellegatta, Fabio; Pirro, Matteo; Pisciotta, Livia; Pujia, Roberta; Sarzani, Riccardo; Scicali, Roberto; Suppressa, Patrizia; Zambon, Sabina; Zenti, Maria Grazia; Calandra, Sebastiano; Catapano, Alberico Luigi; Tarugi, Patrizia; Galimberti, Federica; Casula, Manuela; Capra, Maria Elena
abstract
: Detection and treatment of patients with familial hypercholesterolemia (FH) starting from childhood is fundamental to reduce morbidity and mortality. The activity of National realities such as the LIPIGEN (LIpid transPort disorders Italian GEnetic Network) Paediatric Group, founded in 2018, is a milestone in this context. The aim of this exploratory survey, conducted in October 2021 among Italian lipid clinics included in the LIPIGEN Paediatric Group, was to investigate the current clinical approach in the management and treatment of paediatric patients with suspected FH. A digital questionnaire composed of 20 questions investigating nutritional treatment and nutraceutical and pharmacological therapy for children and adolescents with FH was proposed to the principal investigators of 30 LIPIGEN centres. Twenty-four centres responded to the section referring to children aged < 10 years and 30 to that referring to adolescents. Overall, 66.7% of children and 73.3% of adolescents were given lipid-lowering nutritional treatment as the first intervention level for at least 3-4 months (29.2% and 23.3%) or 6-12 months (58.3% and 53.3%). Nutraceuticals were considered in 41.7% (regarding children) and 50.0% (regarding adolescents) of the centres as a supplementary approach to diet. Lipid-lowering drug therapy initiation was mainly recommended (91.7% and 80.0%). In 83.3% of children and 96.7% of adolescents, statins were the most frequently prescribed drug. We highlighted several differences in the treatment of paediatric patients with suspected FH among Italian centres; however, the overall approach is in line with the European Atherosclerosis Society (EAS) recommendations for FH children and adolescents. We consider this survey as a starting point to reinforce collaboration between LIPIGEN centres and to elaborate in the near future a consensus document on the management of paediatric patients with suspected FH so as to improve and uniform detection, management, and treatment of these patients in our country.
2023
- Lipoprotein(a) Genotype Influences the Clinical Diagnosis of Familial Hypercholesterolemia
[Articolo su rivista]
Olmastroni, Elena; Gazzotti, Marta; Averna, Maurizio; Arca, Marcello; Tarugi, Patrizia; Calandra, Sebastiano; Bertolini, Stefano; Catapano, Alberico L; Casula, Manuela; Marcello, Arca; Laura, D'Erasmo; Maurizio, Averna; Angelo Baldassare Cefalù, ; Andrea, Bartuli; Paola Sabrina Buonuomo, ; Andrea, Benso; Guglielmo, Beccuti; Giacomo, Biasucci; Maria Elena Capra, ; Gianni, Biolo; Pierandrea, Vinci; Luca, Bonanni; Claudio, Borghi; Sergio, D'Addato; Antonio Carlo Bossi, ; Giancarla, Meregalli; Adriana, Branchi; Paolo, Calabrò; Carubbi, Francesca; Nascimbeni, Fabio; Francesco, Cipollone; Marco, Bucci; Nadia, Citroni; Maria Del Ben, ; Francesco, Baratta; Massimo, Federici; Martina, Montagna; Claudio, Ferri; Serena, Notargiacomo; Anna Maria Fiorenza, ; Emanuela, Colombo; Giuliana, Fortunato; Maria Donata Di Taranto, ; Andrea, Giaccari; Simona, Moffa; Francesco, Giorgino; Sergio Di Molfetta, ; Ornella, Guardamagna; Luisa De Sanctis, ; Arcangelo, Iannuzzi; Raimondo, Cavallaro; Gabriella, Iannuzzo; Marco, Gentile; Iughetti, Lorenzo; Bruzzi, Patrizia; Salvatore, Lia; Alessandro, Lupi; Giuseppe, Mandraffino; Arianna, Toscano; Rossella, Marcucci; Martina, Berteotti; Lorenzo, Maroni; Fabiana, Locatelli; Tiziana, Montalcini; Giuliana, Mombelli; Sandro, Muntoni; Davide, Baldera; Gianfranco, Parati; Angelina, Passaro; Valerio, Pecchioli; Cristina, Pederiva; Giuseppe, Banderali; Antonio, Pipolo; Debora, D'Elia; Matteo, Pirro; Vanessa, Bianconi; Livia, Pisciotta; Elena, Formisano; Francesco, Purrello; Roberto, Scicali; Elena, Repetti; Elena, Cantino; Elisabetta, Rinaldi; Elena, Sani; Riccardo, Sarzani; Francesco, Spannella; Francesco, Sbrana; Beatrice Dal Pino, ; Patrizia, Suppressa; Cocco, VERONICA MARGHERITA; Chiara, Trenti; Emanuele Alberto Negri, ; Josè Pablo Werba, ; Alessandra, Romandini; Sabina, Zambon; Alberto, Zambon; Maria Grazia Zenti, ; Giulia, Fainelli; Fabio, Pellegatta; Liliana, Grigore; Katia, Bonomo; Eleonora, Capatti; Ada, Cutolo; Fabio, Fimiani; Simonetta, Genovesi; Sandro, Inchiostro; Chiara, Pavanello; Roberta, Pujia; Alon, Schaffer; Stefano, Bertolini; CALANDRA BUONAURA, Sebastiano; Alberico Luigi Catapano, ; Manuela, Casula; Elena, Olmastroni; Tarugi, Patrizia Maria; Marta, Gazzotti; Federica, Galimberti
abstract
BackgroundEvidence suggests that LPA risk genotypes are a possible contributor to the clinical diagnosis of familial hypercholesterolemia (FH). This study aimed at determining the prevalence of LPA risk variants in adult individuals with FH enrolled in the Italian LIPIGEN (Lipid Transport Disorders Italian Genetic Network) study, with (FH/M+) or without (FH/M-) a causative genetic variant. Methods and ResultsAn lp(a) [lipoprotein(a)] genetic score was calculated by summing the number risk-increasing alleles inherited at rs3798220 and rs10455872 variants. Overall, in the 4.6% of 1695 patients with clinically diagnosed FH, the phenotype was not explained by a monogenic or polygenic cause but by genotype associated with high lp(a) levels. Among 765 subjects with FH/M- and 930 subjects with FH/M+, 133 (17.4%) and 95 (10.2%) were characterized by 1 copy of either rs10455872 or rs3798220 or 2 copies of either rs10455872 or rs3798220 (lp(a) score >= 1). Subjects with FH/M- also had lower mean levels of pretreatment low-density lipoprotein cholesterol than individuals with FH/M+ (t test for difference in means between FH/M- and FH/M+ groups <0.0001); however, subjects with FH/M- and lp(a) score >= 1 had higher mean (SD) pretreatment low-density lipoprotein cholesterol levels (223.47 [50.40] mg/dL) compared with subjects with FH/M- and lp(a) score=0 (219.38 [54.54] mg/dL for), although not statistically significant. The adjustment of low-density lipoprotein cholesterol levels based on lp(a) concentration reduced from 68% to 42% the proportion of subjects with low-density lipoprotein cholesterol level >= 190 mg/dL (or from 68% to 50%, considering a more conservative formula). ConclusionsOur study supports the importance of measuring lp(a) to perform the diagnosis of FH appropriately and to exclude that the observed phenotype is driven by elevated levels of lp(a) before performing the genetic test for FH.
2023
- Refinement of the diagnostic approach for the identification of children and adolescents affected by familial hypercholesterolemia: Evidence from the LIPIGEN study
[Articolo su rivista]
Casula, M.; Gazzotti, M.; Capra, M. E.; Olmastroni, E.; Galimberti, F.; Catapano, A. L.; Pederiva, C.; Anesi, A.; Arca, M.; Auricchio, R.; Averna, M.; Baldera, D.; Banderali, G.; Beccuti, G.; Benso, A.; Berteotti, M.; Bertolini, S.; Bianconi, V.; Biasucci, G.; Biolo, G.; Bonanni, L.; Borghi, C.; Bossi, A. C.; Branchi, A.; Bruzzi, P.; Bucci, M.; Buonuomo, P. S.; Calabro, P.; Calandra, S.; Carubbi, F.; Cavallaro, R.; Cefalu, A. B.; Cesaro, A.; Cipollone, F.; Citroni, N.; Colombo, E.; Coppola, C.; D'Addato, S.; Dal Pino, B.; Dalla Nora, E.; De Corrado, G.; Del Ben, M.; Di Molfetta, S.; Di Taranto, M. D.; Fainelli, G.; Federici, M.; Ferri, C.; Fiorenza, A. M.; Formisano, E.; Fortunato, G.; Giaccari, A.; Giorgino, F.; Grigore, L.; Guardamagna, O.; Iannuzzi, A.; Iannuzzo, G.; Iughetti, L.; Lia, S.; Longo, S.; Lupi, A.; Mandraffino, G.; Marcucci, R.; Maroni, L.; Massini, G.; Mazza, E.; Melchioda, E.; Meregalli, G.; Minicocci, I.; Moffa, S.; Mombelli, G.; Muntoni, S.; Nascimbeni, F.; Negri, E. A.; Notargiacomo, S.; Panfili, F. M.; Parati, G.; Passaro, A.; Pavanello, C.; Pecchioli, V.; Pecchioli, L.; Pellegatta, F.; Perla, F. M.; Pipolo, A.; Piro, S.; Pirro, M.; Pisciotta, L.; Pujia, R.; Putotto, C.; Repetti, E.; Rinaldi, E.; Romandini, A.; Sani, E.; Sarnari, S.; Sarzani, R.; Sbrana, F.; Scicali, R.; Scuruchi, M.; Suppressa, P.; Tarugi, P.; Trenti, C.; Vinci, P.; Werba, J. P.; Zambon, S.; Zambon, A.; Zenti, M. G.
abstract
Background and aims: We aimed to describe the limitations of familiar hypercholesterolemia (FH) diagnosis in childhood based on the presence of the typical features of FH, such as physical sings of cholesterol accumulation and personal or family history of premature cardiovascular disease or hypercholesterolemia, comparing their prevalence in the adult and paediatric FH population, and to illustrate how additional information can lead to a more effective diagnosis of FH at a younger age. Methods: From the Italian LIPIGEN cohort, we selected 1188 (≥18 years) and 708 (<18 years) genetically-confirmed heterozygous FH, with no missing personal FH features. The prevalence of personal and familial FH features was compared between the two groups. For a sub-group of the paediatric cohort (N = 374), data about premature coronary heart disease (CHD) in second-degree family members were also included in the evaluation. Results: The lower prevalence of typical FH features in children/adolescents vs adults was confirmed: the prevalence of tendon xanthoma was 2.1% vs 13.1%, and arcus cornealis was present in 1.6% vs 11.2% of the cohorts, respectively. No children presented clinical history of premature CHD or cerebral/peripheral vascular disease compared to 8.8% and 5.6% of adults, respectively. The prevalence of premature CHD in first-degree relatives was significantly higher in adults compared to children/adolescents (38.9% vs 19.7%). In the sub-cohort analysis, a premature CHD event in parents was reported in 63 out of 374 subjects (16.8%), but the percentage increased to 54.0% extending the evaluation also to second-degree relatives. Conclusions: In children, the typical FH features are clearly less informative than in adults. A more thorough data collection, adding information about second-degree relatives, could improve the diagnosis of FH at younger age.
2022
- Comparison of two polygenic risk score to identify non-monogenic primary hypocholesterolemias in a large cohort of Italian hypocholesterolemic subjects
[Articolo su rivista]
Cefalù, Angelo B.; Spina, Rossella; Noto, Davide; Rabacchi, Claudio; Giammanco, Antonina; Simone, Maria Luisa; Brucato, Federica; Scrimali, Chiara; Gueli-Alletti, Maria Grazia; Barbagallo, Carlo M.; Tarugi, Patrizia; Averna, Maurizio R.
abstract
Background
Primary Hypobetalipoproteinemias (HBL) are a group of dominant and recessive monogenic genetic disorders caused by mutations in APOB, PCSK9, ANGPTL3, MTTP, Sar1b genes and characterized by plasma levels of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) below the 5th percentile of the distribution in a given population. Mutations in the candidate genes account only for a small proportion of subjects with HBL suggesting a role for a polygenic contribution to the low cholesterol phenotype.
Objective
To explore the complex genetic architecture of HBL we compared two polygenic risk scores in order to assess the role of the polygenic burden and the differences in the clinical phenotype between monogenic and polygenic HBL; we studied a cohort of 170 subjects with primary HBL referred over a 25-year period to 2 Italian reference centers have been studied.
Methods
The genetic analyses have been based on: Sanger sequencing, in-house NGS customized panel and two scores, PRS1 and PRS2 for the polygenic burden.
Results
Sixty 60 (35%) and 63 (37%) subjects had a monogenic and polygenic HBL respectively. LDL-C plasma levels were significantly lower in monogenic HBL (30.87 ± 3.12 mg/dl) compared with the non-monogenic HBL (42.80 ± 2.18 mg/dl) (p<0.002) with no differences in the percentage of fatty liver.
Conclusion
Only PRS1 is effective in detecting polygenic HBL while PRS2 does not improve the polygenic diagnosis.
2022
- Familial chylomicronemia syndrome. A sixty year follow-up in two siblings and their kindreds. Nosological and clinical considerations
[Articolo su rivista]
Vigna, G. B.; Citroni, N.; Tarugi, P.; Fellin, R.
abstract
Familial chylomicronemia syndrome (FCS) is a rare and severe genetic disorder, characterized by marked elevation of plasma triglycerides, often diagnosed in infancy. We describe the long-term follow-up (almost 60 years), the diagnostic assessment and the management of two siblings with severe hypertriglyceridemia and a history of pancreatitis who also developed cardiovascular complications later in life. We recently disclosed that the surviving index case was homozygous for a pathogenic LPL gene variant (c.984 G>T, p.M328I). The same variant was also found in two apparently unrelated siblings with FCS living in the same geographical area as the index case.
2022
- HDL‐mediated reduction of cholesterol content inhibits the proliferation of prostate cancer cells induced by LDL: Role of ABCA1 and proteasome inhibition
[Articolo su rivista]
Ossoli, Alice; Giorgio, Eleonora; Cetti, Federica; Ruscica, Massimiliano; Rabacchi, Claudio; Tarugi, Patrizia; Parini, Paolo; Pedrelli, Matteo; Gomaraschi, Monica
abstract
High-density lipoproteins (HDL) are well known for their atheroprotective function, mainly due to their ability to remove cell cholesterol and to exert antioxidant and anti-inflammatory activities. Through the same mechanisms HDL could also affect the development and progression of tumors. Cancer cells need cholesterol to proliferate, especially in hormone-dependent tumors, as prostate cancer (PCa). Aim of the study was to investigate the ability of HDL to modulate cholesterol content and metabolism in androgen receptor (AR)-positive and AR-null PCa cell lines and the consequences on cell proliferation. HDL inhibited colony formation of LNCaP and PC3 cells. HDL reduced cell cholesterol content and proliferation of LNCaP cells loaded with low-density lipoproteins but were not effective on PC3 cells. Here, the expression of the ATP-binding cassette transporter A1 (ABCA1) was markedly reduced due to proteasome degradation. Bortezomib, a proteasome inhibitor, restored ABCA1 expression and HDL ability to promote cholesterol removal from PC3; consequently, HDL inhibited the proliferation of PC3 cells induced by LDL only after bortezomib pre-treatment. In conclusion, the antiproliferative activity of HDL on AR-positive and AR-null PCa cells also rely on cholesterol removal, a process in which the ABCA1 transporter plays a key role.
2022
- Worldwide experience of homozygous familial hypercholesterolaemia: retrospective cohort study
[Articolo su rivista]
Tromp, Tycho R; Hartgers, Merel L; Hovingh, G Kees; Vallejo-Vaz, Antonio J; Ray, Kausik K; Soran, Handrean; Freiberger, Tomas; Bertolini, Stefano; Harada-Shiba, Mariko; Blom, Dirk J; Raal, Frederick J; Cuchel, Marina; Tromp, Tycho R.; Hartgers, Merel L.; Hovingh, G. Kees; Vallejo-Vaz, Antonio J.; Ray, Kausik K.; Soran, Handrean; Freiberger, Tomas; Bertolini, Stefano A.; Harada-Shiba, Mariko; Pang, Jing; Watts, Gerald F.; Greber-Platzer, Susanne; Mäser, Martin; Stulnig, Thomas M.; Ebenbichler, Christoph F.; Bin Thani, Khalid; Cassiman, David; Descamps, Olivier S.; Rymen, Daisy; Witters, Peter; Santos, Raul D.; Brunham, Liam R.; Francis, Gordon A.; Genest, Jacques; Hegele, Robert A.; Kennedy, Brooke A.; Ruel, Isabelle; Sherman, Mark H.; Jiang, Long; Wang, Luya; Reiner, Željko; Blaha, Vladimir; Ceska, Richard; Dvorakova, Jana; Dlouhy, Lubomir; Horak, Pavel; Soska, Vladimir; Tichy, Lukas; Urbanek, Robin; Vaverkova, Helena; Vrablik, Michal; Zemek, Stanislav; Zlatohlavek, Lukas; Emil, Sameh; Naguib, Tarek; Reda, Ashraf; Béliard, Sophie; Bruckert, Eric; Gallo, Antonio; Elisaf, Moses S.; Kolovou, Genovefa; Cohen, Hofit; Durst, Ronen; Dann, Eldad J.; Elis, Avishay; Hussein, Osama; Leitersdorf, Eran; Schurr, Daniel; Setia, Nitika; Verma, Ishwar C.; Alareedh, Mohammed D.; Al-Khnifsawi, Mutaz; Abdalsahib Al-Zamili, Ali F.; Rhadi, Sabah H.; Shaghee, Foaad K.; Arca, Marcello; Averna, Maurizio; Bartuli, Andrea; Bucci, Marco; Buonuomo, Paola S.; Calabrò, Paolo; Calandra, Sebastiano; Casula, Manuela; Catapano, Alberico L.; Cefalù, Angelo B.; Cicero, Arrigo F. G.; D'Addato, Sergio; D'Erasmo, Laura; Di Costanzo, Alessia; Fasano, Tommaso; Gazzotti, Marta; Giammanco, Antonina; Iannuzzo, Gabriella; Ibba, Anastasia; Negri, Emanuele A.; Pasta, Andrea; Pavanello, Chiara; Pisciotta, Livia; Rabacchi, Claudio; Ripoli, Carlo; Sampietro, Tiziana; Sbrana, Francesco; Sileo, Fulvio; Suppressa, Patrizia; Tarugi, Patrizia; Trenti, Chiara; Zenti, Maria G.; Hori, Mika; Ayesh, Mahmoud H.; Azar, Sami T.; Bitar, Fadi F.; Fahed, Akl C.; Moubarak, Elie M.; Nemer, Georges; Nawawi, Hapizah M.; Madriz, Ramón; Mehta, Roopa; Cupido, Arjen J.; Defesche, Joep C.; Reijman, M. Doortje; Roeters-van Lennep, Jeanine E.; Stroes, Erik S. G.; Wiegman, Albert; Zuurbier, Linda; Al-Waili, Khalid; Sadiq, Fouzia; Chlebus, Krzysztof; Bourbon, Mafalda; Gaspar, Isabel M.; Lalic, Katarina S.; Ezhov, Marat V.; Susekov, Andrey V.; Groselj, Urh; Charng, Min-Ji; Khovidhunkit, Weerapan; Aktan, Melih; Altunkeser, Bulent B.; Demircioglu, Sinan; Kose, Melis; Gokce, Cumali; Ilhan, Osman; Kayikcioglu, Meral; Kaynar, Leyla G.; Kuku, Irfan; Kurtoglu, Erdal; Okutan, Harika; Ozcebe, Osman I.; Pekkolay, Zafer; Sag, Saim; Salcioglu, Osman Z.; Temizhan, Ahmet; Yenercag, Mustafa; Yilmaz, Mehmet; Yilmaz Yasar, Hamiyet; Mitchenko, Olena; Lyons, Alexander R. M.; Stevens, Christophe A. T.; Brothers, Julie A.; Hudgins, Lisa C.; Nguyen, Christina; Alieva, Rano; Shek, Aleksandr; Do, Doan-Loi; Kim, Ngoc-Thanh; Le, Hong-An; Le, Thanh-Tung; Nguyen, Mai-Ngoc T.; Truong, Thanh-Huong; Blom, Dirk J.; Raal, Frederick J.; Cuchel, Marina
abstract
Background
Homozygous familial hypercholesterolaemia (HoFH) is a rare inherited disorder resulting in extremely elevated low-density lipoprotein cholesterol levels and premature atherosclerotic cardiovascular disease (ASCVD). Current guidance about its management and prognosis stems from small studies, mostly from high-income countries. The objective of this study was to assess the clinical and genetic characteristics, as well as the impact, of current practice on health outcomes of HoFH patients globally.
Methods
The HoFH International Clinical Collaborators registry collected data on patients with a clinical, or genetic, or both, diagnosis of HoFH using a retrospective cohort study design. This trial is registered with ClinicalTrials.gov, NCT04815005.
Findings
Overall, 751 patients from 38 countries were included, with 565 (75%) reporting biallelic pathogenic variants. The median age of diagnosis was 12·0 years (IQR 5·5–27·0) years. Of the 751 patients, 389 (52%) were female and 362 (48%) were male. Race was reported for 527 patients; 338 (64%) patients were White, 121 (23%) were Asian, and 68 (13%) were Black or mixed race. The major manifestations of ASCVD or aortic stenosis were already present in 65 (9%) of patients at diagnosis of HoFH. Globally, pretreatment LDL cholesterol levels were 14·7 mmol/L (IQR 11·6–18·4). Among patients with detailed therapeutic information, 491 (92%) of 534 received statins, 342 (64%) of 534 received ezetimibe, and 243 (39%) of 621 received lipoprotein apheresis. On-treatment LDL cholesterol levels were lower in high-income countries (3·93 mmol/L, IQR 2·6–5·8) versus non-high-income countries (9·3 mmol/L, 6·7–12·7), with greater use of three or more lipid-lowering therapies (LLT; high-income 66% vs non-high-income 24%) and consequently more patients attaining guideline-recommended LDL cholesterol goals (high-income 21% vs non-high-income 3%). A first major adverse cardiovascular event occurred a decade earlier in non-high-income countries, at a median age of 24·5 years (IQR 17·0–34·5) versus 37·0 years (29·0–49·0) in high-income countries (adjusted hazard ratio 1·64, 95% CI 1·13–2·38).
Interpretation
Worldwide, patients with HoFH are diagnosed too late, undertreated, and at high premature ASCVD risk. Greater use of multi-LLT regimens is associated with lower LDL cholesterol levels and better outcomes. Significant global disparities exist in treatment regimens, control of LDL cholesterol levels, and cardiovascular event-free survival, which demands a critical re-evaluation of global health policy to reduce inequalities and improve outcomes for all patients with HoFH.
Funding
Amsterdam University Medical Centers, Location Academic Medical Center; Perelman School of Medicine at the University of Pennsylvania; and European Atherosclerosis Society
2020
- Homozygous familial hypercholesterolemia in Italy: Clinical and molecular features.
[Articolo su rivista]
Bertolini, S.; Calandra, S.; Arca, M.; Averna, M.; Catapano, A. L.; Tarugi, P.; Bartuli, A.; Bucci, M.; Buonuomo, P. S.; Calabrò, P.; Casula, M.; Cefalù, A. B.; Cicero, A.; D'Addato, S.; D'Erasmo, L.; Fasano, T.; Iannuzzo, G.; Ibba, A.; Negri, E. A.; Pasta, A.; Pavanello, C.; Pisciotta, L.; Rabacchi, C.; Ripoli, C.; Sampietro, T.; Sbrana, F.; Sileo, F.; Suppressa, P.; Trenti, C.; Zenti, M. G.
abstract
2019
- Angiopoietin-like protein 3 (ANGPTL3) deficiency and familial combined hypolipidemia
[Articolo su rivista]
Tarugi, P.; Bertolini, S.; Calandra, S.
abstract
Three members of the angiopoietin-like (ANGPTL) protein family-ANGPTL3, ANGPTL4 and ANGPTL8- are important regulators of plasma lipoproteins. They inhibit the enzyme lipoprotein lipase, which plays a key role in the intravascular lipolysis of triglycerides present in some lipoprotein classes. This review focuses on the role of ANGPTL3 as emerged from the study of genetic variants of Angptl3 gene in mice and humans. Both loss of function genetic variants and inactivation of Angptl3 gene in mice are associated with a marked reduction of plasma levels of triglyceride and cholesterol and an increased activity of lipoprotein lipase and endothelial lipase. In humans with ANGPTL3 deficiency, caused by homozygous loss of function (LOF) variants of Angptl3 gene, the levels of all plasma lipoproteins are greatly reduced. This plasma lipid disorder referred to as familial combined hypolipidemia (FHBL2) does not appear to be associated with distinct pathological manifestations. Heterozygous carriers of LOF variants have reduced plasma levels of total cholesterol and triglycerides and are at lower risk of developing atherosclerotic cardiovascular disease, as compared to non-carriers. These observations have paved the way to the development of strategies to reduce the plasma level of atherogenic lipoproteins in man by the inactivation of ANGPTL3, using either a specific monoclonal antibody or anti-sense oligonucleotides.
2019
- In vitro functional characterization of splicing variants of the APOB gene found in familial hypobetalipoproteinemia
[Articolo su rivista]
Rabacchi, C.; Simone, M. L.; Pisciotta, L.; Di Leo, E.; Bocchi, D.; Pietrangelo, A.; D'Addato, S.; Bertolini, S.; Calandra, S.; Tarugi, P.
abstract
Background: Familial hypobetalipoproteinemia type 1 (FHBL-1) is a codominant disorder characterized by greatly reduced plasma levels of total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B. Rare exonic pathogenic variants of APOB gene (nonsense variants, minute deletions/insertions and nonsynonymous variants) have been frequently reported in subjects with FHBL-1. Also, rare intronic variants of APOB located at intron/exon junctions and assumed to affect splicing have been reported. However, the pathogenicity of most of these intronic variants remains to be established. Objective: The objective of this study was the in vitro functional characterization of six splicing variants of APOB gene identified in seven putative FHBL-1 heterozygotes. Methods: ApoB minigenes harboring each variant were expressed in COS-1 cells and their transcripts were sequenced. Results: Four novel variants (c.237+1G>A, c.818+5G>A, c.3000-1G>T, and c.3842+1G>A), predicted in silico to obliterate splice site activity, were found to generate abnormal transcripts. The abnormal transcripts were generated by the activation of cryptic splice sites or exon skipping. All these transcripts harbored a premature termination codon and were predicted to encode truncated apoBs devoid of function. The predicted translation products were: i) p.(Lys41Serfs*2) and p.(Val80Ilefs*10) for c.237+1G>A; ii) p.(Asn274*) for c.818+5G>A; iii) p.(Leu1001Alafs*10) for c.3000-1G>T, and iv) p.(Ser1281Argfs*2) for c.3842+1G>A. Two previously annotated rare variants (c.905-15C>G and c.1618-4G>A) with uncertain effect in silico were found to generate only wild-type transcripts. Conclusions: These in vitro minigene expression studies support the assignment of pathogenicity to four novel splice site variants of APOB gene found in FHBL-1.
2019
- Novel mutations of SAR1B gene in four children with chylomicron retention disease
[Articolo su rivista]
Simone, M. L.; Rabacchi, C.; Kuloglu, Z.; Kansu, A.; Ensari, A.; Demir, A. M.; Hizal, G.; Di Leo, E.; Bertolini, S.; Calandra, S.; Tarugi, P.
abstract
Background: Intestinal lipid malabsorption, resulting from an impaired formation or secretion of chylomicrons and associated with severe hypobetalipoproteinemia (HBL), may be due to biallelic mutations in APOB (homozygous FHBL type-1), MTTP (abetalipoproteinemia), or SAR1B (chylomicron retention disease). Objective: We investigated four children, each born from consanguineous parents, presenting with steatorrhea, malnutrition, accumulation of lipids in enterocytes, and severe hypocholesterolemia with an apparent recessive transmission. Methods: We sequenced a panel of genes whose variants may be associated with HBL. Results: Case 1, a 9-month-old male, was found to be homozygous for a SAR1B variant (c.49 C>T), predicted to encode a truncated Sar1b protein devoid of function (p.Gln17*). Case 2, a 4-year-old male, was found to be homozygous for a SAR1B missense variant [c.409 G>C, p.(Asp137His)], which affects a highly conserved residue close to the Sar1b guanosine recognition site. Case 3, a 6-year-old male, was found to be homozygous for an ∼6 kb deletion of the SAR1B gene, which eliminates exon 2; this deletion causes the loss of the ATG translation initiation codon in the SAR1B mRNA. The same homozygous mutation was found in an 11-month-old child (case 4) who was related to case 3. Conclusions: We report 4 children with intestinal lipid malabsorption were found to have chylomicron retention disease due to 3 novel variants in the SAR1B gene.
2018
- Evaluation of the performance of Dutch Lipid Clinic Network score in an Italian FH population: The LIPIGEN study
[Articolo su rivista]
Casula, Manuela; Olmastroni, Elena; Pirillo, Angela; Catapano, Alberico Luigi; Arca, Marcello; Averna, Maurizio; Bertolini, Stefano; Calandra, Sebastiano; Tarugi, Patrizia; Pellegatta, Fabio; Angelico, Francesco; Bartuli, Andrea; Biasucci, Giacomo; Biolo, Gianni; Bonanni, Luca; Bonomo, Katia; Borghi, Claudio; Bossi, Antonio Carlo; Branchi, Adriana; Carubbi, Francesca; Cipollone, Francesco; Citroni, Nadia; Federici, Massimo; Ferri, Claudio; Fiorenza, Anna Maria; Giaccari, Andrea; Giorgino, Francesco; Guardamagna, Ornella; Iannuzzi, Arcangelo; Iughetti, Lorenzo; Lupattelli, Graziana; Lupi, Alessandro; Mandraffino, Giuseppe; Marcucci, Rossella; Maroni, Lorenzo; Miccoli, Roberto; Mombelli, Giuliana; Muntoni, Sandro; Pecchioli, Valerio; Pederiva, Cristina; Pipolo, Antonio; Pisciotta, Livia; Pujia, Arturo; Purrello, Francesco; Repetti, Elena; Rubba, Paolo; Sabbà, Carlo; Sampietro, Tiziana; Sarzani, Riccardo; Tagliabue, Milena Paola; Trenti, Chiara; Vigna, Giovanni Battista; Werba, Josè Pablo; Zambon, Sabina; Zenti, Maria Grazia; Minicocci, Ilenia; Noto, Davide; Fortunato, Giuliana; Banderali, Giuseppe; Benso, Andrea; Bigolin, Paola; Bonora, Enzo; Bruzzi, Patrizia; Bucci, Marco; Buonuomo, Paola Sabrina; Capra, Maria Elena; Cardolini, Iris; Cefalù, Baldassarre; Cervelli, Nazzareno; Chiariello, Giuseppe; Cocci, Guido; Colombo, Emanuela; Cremonini, Anna Laura; D'addato, Sergio; D'erasmo, Laura; Dal Pino, Beatrice; De Sanctis, Luisa; De Vita, Emanuele; Del Ben, Maria; Di Costanzo, Alessia; Di Taranto, Maria Donata; Fasano, Tommaso; Gentile, Luigi; Gentile, Marco; Ghirardello, Omar; Grigore, Liliana; Lussu, Milena; Meregalli, Giancarla; Moffa, Simona; Montalcini, Tiziana; Morgia, Valeria; Nascimbeni, Fabio; Pasta, Andrea; Pavanello, Chiara; Saitta, Antonino; Scicali, Roberto; Siepi, Donatella; Spagnolli, Walter; Spina, Rossella; Sticchi, Elena; Suppressa, Patrizia; Vigo, Lorenzo; Vinci, Pierandrea; Manzato, Enzo; Tragni, Elena; Zampoleri, Veronica
abstract
Background and aims: Familial hypercholesterolemia (FH) is an inherited disorder characterized by high levels of blood cholesterol from birth and premature coronary heart disease. Thus, the identification of FH patients is crucial to prevent or delay the onset of cardiovascular events, and the availability of a tool helping with the diagnosis in the setting of general medicine is essential to improve FH patient identification. Methods: This study evaluated the performance of the Dutch Lipid Clinic Network (DLCN) score in FH patients enrolled in the LIPIGEN study, an Italian integrated network aimed at improving the identification of patients with genetic dyslipidaemias, including FH. Results: The DLCN score was applied on a sample of 1377 adults (mean age 42.9 ± 14.2 years) with genetic diagnosis of FH, resulting in 28.5% of the sample classified as probable FH and 37.9% as classified definite FH. Among these subjects, 43.4% had at least one missing data out of 8, and about 10.0% had 4 missing data or more. When analyzed based on the type of missing data, a higher percentage of subjects with at least 1 missing data in the clinical history or physical examination was classified as possible FH (DLCN score 3–5). We also found that using real or estimated pre-treatment LDL-C levels may significantly modify the DLCN score. Conclusions: Although the DLCN score is a useful tool for physicians in the diagnosis of FH, it may be limited by the complexity to retrieve all the essential information, suggesting a crucial role of the clinical judgement in the identification of FH subjects.
2018
- Overview of the current status of familial hypercholesterolaemia care in over 60 countries - The EAS Familial Hypercholesterolaemia Studies Collaboration (FHSC)
[Articolo su rivista]
Vallejo-Vaz, A. J.; Marco, M. D.; Stevens, C. A. T.; Akram, A.; Freiberger, T.; Hovingh, G. K.; Kastelein, J. J. P.; Mata, P.; Raal, F. J.; Santos, R. D.; Soran, H.; Watts, G. F.; Abifadel, M.; Aguilar-Salinas, C. A.; Al-Khnifsawi, M.; Alkindi, F. A.; Alnouri, F.; Alonso, R.; Al-Rasadi, K.; Al-Sarraf, A.; Ashavaid, T. F.; Binder, C. J.; Bogsrud, M. P.; Bourbon, M.; Bruckert, E.; Chlebus, K.; Corral, P.; Descamps, O.; Durst, R.; Ezhov, M.; Fras, Z.; Genest, J.; Groselj, U.; Harada-Shiba, M.; Kayikcioglu, M.; Lalic, K.; Lam, C. S. P.; Latkovskis, G.; Laufs, U.; Liberopoulos, E.; Lin, J.; Maher, V.; Majano, N.; Marais, A. D.; Marz, W.; Mirrakhimov, E.; Miserez, A. R.; Mitchenko, O.; Nawawi, H. M.; Nordestgaard, B. G.; Paragh, G.; Petrulioniene, Z.; Pojskic, B.; Postadzhiyan, A.; Reda, A.; Reiner, Z.; Sadoh, W. E.; Sahebkar, A.; Shehab, A.; Shek, A. B.; Stoll, M.; Su, T. -C.; Subramaniam, T.; Susekov, A. V.; Symeonides, P.; Tilney, M.; Tomlinson, B.; Truong, T. -H.; Tselepis, A. D.; Tybjaerg-Hansen, A.; Vazquez-Cardenas, A.; Viigimaa, M.; Vohnout, B.; Widen, E.; Yamashita, S.; Banach, M.; Gaita, D.; Jiang, L.; Nilsson, L.; Santos, L. E.; Schunkert, H.; Tokgozoglu, L.; Car, J.; Catapano, A. L.; Ray, K. K.; Schreier, L.; Pang, J.; Dieplinger, H.; Hanauer-Mader, G.; Desutter, J.; Langlois, M.; Mertens, A.; Rietzschel, E.; Wallemacq, C.; Isakovic, D.; Dzankovic, A. M.; Obralija, J.; Pojskic, L.; Sisic, I.; Stimjanin, E.; Torlak, V. A.; Jannes, C. E.; Krieger, J. E.; Pereira, A. C.; Ruel, I.; Asenjo, S.; Cuevas, A.; Pecin, I.; Miltiadous, G.; Panayiotou, A. G.; Vrablik, M.; Benn, M.; Heinsar, S.; Beliard, S.; Gouni-Berthold, I.; Hengstenberg, W.; Julius, U.; Kassner, U.; Klose, G.; Konig, C.; Konig, W.; Otte, B.; Parhofer, K.; Schatz, U.; Schmidt, N.; Steinhagen-Thiessen, E.; Vogt, A.; Antza, C.; Athyros, V.; Bilianou, E.; Boufidou, A.; Chrousos, G.; Elisaf, M.; Garoufi, A.; Katsiki, N.; Kolovou, G.; Kotsis, V.; Rallidis, L.; Rizos, C.; Skalidis, E.; Skoumas, I.; Tziomalos, K.; Shawney, J. P. S.; Abbaszadegan, M. R.; Aminzadeh, M.; Hosseini, S.; Mobini, M.; Vakili, R.; Zaeri, H.; Agar, R.; Boran, G.; Colwell, N.; Crowley, V.; Durkin, M.; Griffin, D.; Kelly, M.; Rakovac-Tisdall, A.; Bitzur, R.; Cohen, H.; Eliav, O.; Ellis, A.; Gavish, D.; Harats, D.; Henkin, Y.; Knobler, H.; Leavit, L.; Leitersdorf, E.; Schurr, D.; Shpitzen, S.; Szalat, A.; Arca, M.; Averna, M.; Bertolini, S.; Calandra, S.; Tarugi, P.; Erglis, A.; Gilis, D.; Nesterovics, G.; Saripo, V.; Upena-Roze, A.; Elbitar, S.; Jambart, S.; Khoury, P. E.; Gargalskaite, U.; Kutkiene, S.; Al-Khateeb, A.; An, C. Y.; Ismail, Z.; Kasim, S.; Ibrahim, K. S.; Radzi, A. B. M.; Kasim, N. A.; Nor, N. S. M.; Ramli, A. S.; Razak, S. A.; Muid, S.; Rosman, A.; Sanusi, A. R.; Razman, A. Z.; Nazli, S. A.; Kek, T. L.; Azzopardi, C.; Aguilar Salinas, C. A.; Galan, G.; Rubinstein, A.; Magana-Torres, M. T.; Martagon, A.; Mehta, R.; Wittekoek, M. E.; Isara, A. R.; Obaseki, D. E.; Ohenhen, O. A.; Holven, K. B.; Gruchala, M.; Baranowska, M.; Borowiec-Wolny, J.; Gilis-Malinowska, N.; Michalska-Grzonkowska, A.; Pajkowski, M.; Parczewska, A.; Romanowska-Kocejko, M.; Strozyk, A.; Zarczynska-Buchowiecka, M.; Kleinschmidt, M.; Alves, A. C.; Medeiros, A. M.; Ershova, A.; Korneva, V.; Kuznetsova, T.; Malyshev, P.; Meshkov, A.; Rozhkova, T.; Popovic, L.; Lukac, S. S.; Stosic, L.; Rasulic, I.; Lalic, N. M.; Chua, T. S. J.; Ting, S. P. L.; Raslova, K.; Battelino, T.; Cevc, M.; Jug, B.; Kovac, J.; Podkrajsek, K. T.; Sustar, U.; Trontelj, K. J.; Marais, D.; Isla, L. P.; Martin, F. J.; Charng, M. -J.; Chen, P. -L.; Kayikcioglu, M.; Dell'Oca, N.; Fernandez, G.; Ressia, A.; Reyes, X.; Zelarayan, M.; Alieva, R. B.; Hoshimov, S. U.; Nizamov, U. I.; Kurbanov, R. D.; Lima-Martinez, M. M.; Nguyen, M. -N. T.; Do, D. -L.; Kim, N. -T.; Le, T. -T.; Le, H. -A.
abstract
Background and aims: Management of familial hypercholesterolaemia (FH) may vary across different settings due to factors related to population characteristics, practice, resources and/or policies. We conducted a survey among the worldwide network of EAS FHSC Lead Investigators to provide an overview of FH status in different countries. Methods: Lead Investigators from countries formally involved in the EAS FHSC by mid-May 2018 were invited to provide a brief report on FH status in their countries, including available information, programmes, initiatives, and management. Results: 63 countries provided reports. Data on FH prevalence are lacking in most countries. Where available, data tend to align with recent estimates, suggesting a higher frequency than that traditionally considered. Low rates of FH detection are reported across all regions. National registries and education programmes to improve FH awareness/knowledge are a recognised priority, but funding is often lacking. In most countries, diagnosis primarily relies on the Dutch Lipid Clinics Network criteria. Although available in many countries, genetic testing is not widely implemented (frequent cost issues). There are only a few national official government programmes for FH. Under-treatment is an issue. FH therapy is not universally reimbursed. PCSK9-inhibitors are available in ∼2/3 countries. Lipoprotein-apheresis is offered in ∼60% countries, although access is limited. Conclusions: FH is a recognised public health concern. Management varies widely across countries, with overall suboptimal identification and under-treatment. Efforts and initiatives to improve FH knowledge and management are underway, including development of national registries, but support, particularly from health authorities, and better funding are greatly needed.
2017
- Association between familial hypobetalipoproteinemia and the risk of diabetes. Is this the other side of the cholesterol–diabetes connection? A systematic review of literature
[Articolo su rivista]
Noto, D; Arca, M; Tarugi, Patrizia Maria; Cefalu`, Ab; Barbagallo, Cm; Averna, M.
abstract
Abstract Statin therapy is beneficial in reducing LDL
cholesterol (LDL-C) levels and cardiovascular events, but
it is associated with the risk of incident diabetes mellitus
(DM). Familial hypercholesterolemia (FH) is characterized
by genetically determined high levels of plasma LDL-C
and a low prevalence of DM. LDL-C levels seem then
inversely correlated with prevalence of DM. Familial
hypobetalipoproteinemia (FHBL) represents the genetic
mirror of FH in terms of LDL-C levels, very low in subjects
carrying mutations of APOB, PCSK9 (FHBL1) or
ANGPTL3 (FHBL2). This review explores the hypothesis
that FHBL might represent also the genetic mirror of FH in
terms of prevalence of DM and that it is expected to be
increased in FHBL in comparison with the general population.
A systematic review of published literature on
FHBL was made by searching PubMed (1980–2016) for
articles presenting clinical data on FHBL probands and
relatives. The standardized prevalence rates of DM in
FHBL1 were similar to those of the reference population,
with a prevalence rate of 8.2 and 9.2%, respectively, while
FHBL2 showed a 4.9% prevalence of DM. In conclusion,
low LDL-C levels of FHBL do not seem connected to DM
as it happens in subjects undergoing statin therapy and the
diabetogenic effect of statins has to be explained by
mechanisms that do not rely exclusively on the reduced
levels of LDL-C. The review also summarizes the published
data on the effects of FHBL on insulin sensitivity
and the relationships between FH, statin therapy, FHBL1
and intracellular cholesterol metabolism, evaluating possible
diabetogenic pathways.
2017
- CASO CLINICO: QUANDO LA RISPOSTA ALLA DIETA IPOLIPIDEMIZZANTE DETERMINA LA DIAGNOSI
[Abstract in Atti di Convegno]
Bruzzi, Patrizia; Predieri, Barbara; Madeo, Simona Filomena; Cattini, Umberto; Rabacchi, Claudio; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Iughetti, Lorenzo
abstract
PRESENTAZIONE DEL CASO, STORIA CLINICA E SINTOMATOLOGIA G.M., maschio di 7.8 anni, è stato condotto presso il centro di Dislipidemie in età evolutiva per il riscontro occasionale di ipercolesterolemia [colesterolo totale (CT) 524 mg/dl, LDL-colesterolo (LDL-C) 412 mg/dl, HDL-colesterolo (HDL-C) 52 mg/dl, trigliceridi (TG) 55 mg/dl, Apolipoproteina A (ApoA) 104 mg/dl, ApoB100 253 mg/dl]. Obiettivamente: altezza -2.02 SDS e BMI -1.40 SDS; non riscontro clinico di xantomi e/o xantelasmi, arco corneale o splenomegalia. Anamnesi patologica remota: muta. Anamnesi familiare: positiva per moderata ipercolesterolemia paterna (CT 242 mg/dl), obesità ed ipertensione.
IPOTESI DIAGNOSTICHE E INDAGINI DI I E II LIVELLO Previa esclusione di una forma di ipercolesterolemia secondaria (glicemia, funzionalità tiroidea ed epato-renale nella norma), nel sospetto di ipercolesterolemia familiare omozigote abbiamo eseguito l’analisi genetica dei geni LDL-R ed ARH, risultata negativa per mutazioni. L’ecocardiografi a non documentava alterazioni. DIAGNOSI ED EVENTUALE TERAPIA In considerazione dell’iniziale assetto lipidico, abbiamo posto immediata indicazione di seguire una dieta ipolipidemizzante come da National Cholesterol Education Program ATP III - STEP II (apporto di grassi totali pari al 30% delle kcal quotidiane, grassi saturi < 7% e colesterolo < 200 mg/die). La rivalutazione dell’assetto lipidico, eseguita a distanza di 6 mesi dall’inizio della dietoterapia esclusiva, ha documentato un importante e rapido miglioramento dei valori di CT (203 mg/dl; -39%) e LDL-C (141 mg/dl; -34%). Per questo motivo abbiamo posto il sospetto diagnostico di sitosterolemia.
La sitosterolemia rappresenta un disordine raro (circa 80-100 casi descritti nel mondo) a trasmissione autosomica recessiva caratterizzato da iperassorbimento intestinale e ridotta escrezione biliare di steroli vegetali. Nel nostro paziente abbiamo, quindi, dosato le concentrazioni di steroli vegetali plasmatici (mg/L) che sono risultate elevate (betasitosterolo 228, campesterolo 77.9 e desmosterolo 2.13) ed eseguito l’analisi genetica del gene ABCG8 che ha confermato il sospetto diagnostico, identifi cando la presenza di 2 mutazioni non-senso (esone 3: c.320C>G, p.Ser107*; esone 7: c.1083 G>A, p.Trp361*) come da eterozigosi composta. In considerazione della diagnosi di sitosterolemia confermata geneticamente, abbiamo posto indicazione a seguire un approccio dietetico con restrizione di cibi ad alto contenuto di steroli (olii vegetali, margarina, frutta secca, avocado, cioccolato…) associato ad un’appropriata supplementazione vitaminica.
2017
- Clinical and biochemical characteristics of individuals with low cholesterol syndromes: A comparison between familial hypobetalipoproteinemia and familial combined hypolipidemia.
[Articolo su rivista]
Di Costanzo, A; Di Leo, E; Noto, D; Cefalù, Ab; Minicocci, I; Polito, L; D'Erasmo, L; Cantisani, V; Spina, R; Tarugi, P; Averna, M; Arca, M.
abstract
Abstract
BACKGROUND:
The most frequent monogenic causes of low plasma cholesterol are familial hypobetalipoproteinemia (FHBL1) because of truncating mutations in apolipoprotein B coding gene (APOB) and familial combined hypolipidemia (FHBL2) due to loss-of-function mutations in ANGPTL3 gene.
OBJECTIVE:
A direct comparison of lipid phenotypes of these 2 conditions has never been carried out. In addition, although an increased prevalence of liver steatosis in FHBL1 has been consistently reported, the hepatic consequences of FHBL2 are not well established.
METHODS:
We investigated 350 subjects, 67 heterozygous carriers of APOB mutations, 63 carriers of the p.S17* mutation in ANGPTL3 (57 heterozygotes and 6 homozygotes), and 220 noncarrier normolipemic controls. Prevalence and degree of hepatic steatosis were assessed by ultrasonography.
RESULTS:
A steady decrease of low-density lipoprotein cholesterol levels were observed from heterozygous to homozygous FHBL2 and to FHBL1 individuals, with the lowest levels in heterozygous FHBL1 carrying truncating mutations in exons 1 to 25 of APOB (P for trend <.001). Plasma triglycerides levels were similar in heterozygous FHBL1 and homozygous FHBL2 individuals, but higher in heterozygous FHBL2. The lowest high-density lipoprotein cholesterol levels were detected in homozygous FHBL2 (P for trend <.001). Compared with controls, prevalence and severity of hepatic steatosis were increased in heterozygous FHBL1 (P < .001), but unchanged in FHBL2 individuals.
CONCLUSION:
Truncating APOB mutations showed the more striking low-density lipoprotein cholesterol lowering effect compared with p.S17* mutation in ANGPTL3. Reduced high-density lipoprotein cholesterol levels were the unique lipid characteristic associated with FHBL2. Mutations impairing liver synthesis or secretion of apolipoprotein B are crucial to increase the risk of liver steatosis.
2017
- Familial hypercholesterolemia: The Italian Atherosclerosis Society Network (LIPIGEN)
[Articolo su rivista]
Averna, Maurizio; Cefalã¹, Angelo B.; Casula, Manuela; Noto, Davide; Arca, Marcello; Bertolini, Stefano; Calandra, Sebastiano; Catapano, Alberico L.; Tarugi, Patrizia; Arca, Marcello; Averna, Maurizio; Bertolini, Stefano; Calandra, Sebastiano; Catapano, Alberico Luigi; Tarugi, Patrizia; Pellegatta, Fabio; Angelico, Francesco; Arca, Marcello; Averna, Maurizio; Bartuli, Andrea; Biasucci, Giacomo; Biolo, Gianni; Bonanni, Luca; Bonomo, Katia; Borghi, Claudio; Bossi, Antonio Carlo; Branchi, Adriana; Carubbi, Francesca; Cipollone, Francesco; Citroni, Nadia; Federici, Massimo; Ferri, Claudio; Fiorenza, Anna Maria; Giaccari, Andrea; Giorgino, Francesco; Guardamagna, Ornella; Iannuzzi, Arcangelo; Iughetti, Lorenzo; Lupattelli, Graziana; Mandraffino, Giuseppe; Marcucci, Rossella; Mombelli, Giuliana; Muntoni, Sandro; Pecchioli, Valerio; Pederiva, Cristina; Pipolo, Antonio; Pisciotta, Livia; Pujia, Arturo; Purrello, Francesco; Repetti, Elena; Rubba, Paolo; Sabbã , Carlo; Sampietro, Tiziana; Sarzani, Riccardo; Tagliabue, Milena Paola; Trenti, Chiara; Vigna, Giovanni Battista; Werba, Josà Pablo; Zambon, Sabina; Zenti, Maria Grazia; Montali, Anna; Noto, Davide; Bertolini, Stefano; Calandra, Sebastiano; Fortunato, Giuliana; Grigore, Liliana; Del Ben, Maria; Maranghi, Marianna; Cefalã¹, Angelo B.; Barbagallo, Carlo M.; Buonuomo, Paola Sabrina; Capra, Maria Elena; Vinci, Pierandrea; D'Addato, Sergio; Galbiati, Stella; Nascimbeni, Fabio; Bucci, Marco; Spagnoli, Walter; Cardolini, Iris; Cervelli, Nazzareno; Emanuela, Colombo; Vinsin, A. Sun; Laviola, Luigi; Bello, Francesca; Chiariello, Giuseppe; Predieri, Barbara; Siepi, Donatella; Saitta, Antonino; Giusti, Betti; Pavanello, Chiara; Lussu, Milena; Prati, Lucia; Banderali, Giuseppe; Balleari, Giulia; Montalcini, Tiziana; Scicali, Roberto; Gentile, Luigi; Gentile, Marco; Suppressa, Patrizia; Sbrana, Francesco; Cocci, Guido; Benso, Andrea; Negri, Emanuele Alberto; Ghirardello, Omar; Lorenzo, Vigo; Zambon, Alberto; Enzo, Bonora; Minicocci, Ilenia; Spina, Rossella; Orlando, Camilla; Tarugi, Patrizia; Di Taranto, Maria Donata; Catapano, Alberico Luigi; Casula, Manuela; Chiodo, Lorenzo; Garlaschelli, Katia; Manzato, Enzo; Tragni, Elena
abstract
Background and aims Primary dyslipidemias are a heterogeneous group of disorders characterized by abnormal levels of circulating lipoproteins. Among them, familial hypercholesterolemia is the most common lipid disorder that predisposes for premature cardiovascular disease. We set up an Italian nationwide network aimed at facilitating the clinical and genetic diagnosis of genetic dyslipidemias named LIPIGEN (LIpid TransPort Disorders Italian GEnetic Network). Methods Observational, multicenter, retrospective and prospective study involving about 40 Italian clinical centers. Genetic testing of the appropriate candidate genes at one of six molecular diagnostic laboratories serving as nationwide DNA diagnostic centers. Results and conclusions From 2012 to October 2016, available biochemical and clinical information of 3480 subjects with familial hypercholesterolemia identified according to the Dutch Lipid Clinic Network (DLCN) score were included in the database and genetic analysis was performed in 97.8% of subjects, with a mutation detection rate of 92.0% in patients with DLCN score â¥6. The establishment of the LIPIGEN network will have important effects on clinical management and it will improve the overall identification and treatment of primary dyslipidemias in Italy.
2017
- Impact of rare variants in autosomal dominant hypercholesterolemia causing genes.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Bertolini, Stefano
abstract
PURPOSE OF REVIEW:
The systematic analysis of the major candidate genes in autosomal dominant hypercholesterolemia (ADH) and the use of next-generation sequencing (NGS) technology have made possible the discovery of several rare gene variants whose pathogenic effect in most cases remains poorly defined.
RECENT FINDINGS:
One major advance in the field has been the adoption of a set of international guidelines for the assignment of pathogenicity to low-density lipoprotein receptor (LDLR) gene variants based on the use of softwares, complemented with data available from literature and public databases. The clinical impact of several novel rare variants in LDLR, APOB, PCSK9, APOE genes have been reported in large studies describing patients with ADH found to be homozygotes/compound heterozygotes, double heterozygotes, or simple heterozygotes. In-vitro functional studies have been conducted to clarify the effect of some rare ApoB variants on LDL binding to LDLR and the impact of a rare ApoE variant on the uptake of VLDL and LDL by hepatocytes.
SUMMARY:
The update of the ADH gene variants database and the classification of variants in categories of pathogenicity is a major advance in the understanding the pathophysiology of ADH and in the management of this disorder. The studies of molecularly characterized patients with ADH have emphasized the impact of a specific variant and the variable clinical expression of different genotypes. The functional studies of some variants have increased our understanding of the molecular bases of some forms of ADH.
2017
- Incidental finding of severe hypertriglyceridemia in children. Role of multiple rare variants in genes affecting plasma triglyceride.
[Articolo su rivista]
Buonuomo, Ps; Rabacchi, C; Macchiaiolo, M; Trenti, C; Fasano, T; Tarugi, P; Bartuli, A; Bertolini, S; Calandra, S.
abstract
BACKGROUND:
The incidental finding of severe hypertriglyceridemia (HyperTG) in a child may suggest the diagnosis of familial chylomicronemia syndrome (FCS), a recessive disorder of the intravascular hydrolysis of triglyceride (TG)-rich lipoproteins. FCS may be due to pathogenic variants in lipoprotein lipase (LPL), as well as in other proteins, such as apolipoprotein C-II and apolipoprotein A-V (activators of LPL), GPIHBP1 (the molecular platform required for LPL activity on endothelial surface) and LMF1 (a factor required for intracellular formation of active LPL).
OBJECTIVE:
Molecular characterization of 5 subjects in whom HyperTG was an incidental finding during infancy/childhood.
METHODS:
We performed the parallel sequencing of 20 plasma TG-related genes.
RESULTS:
Three children with severe HyperTG were found to be compound heterozygous for rare pathogenic LPL variants (2 nonsense, 3 missense, and 1 splicing variant). Another child was found to be homozygous for a nonsense variant of APOA5, which was also found in homozygous state in his father with longstanding HyperTG. The fifth patient with a less severe HyperTG was found to be heterozygous for a frameshift variant in LIPC resulting in a truncated Hepatic Lipase. In addition, 1 of the patients with LPL deficiency and the patient with APOA-V deficiency were also heterozygous carriers of a pathogenic variant in LIPC and LPL gene, respectively, whereas the patient with LIPC variant was also a carrier of a rare APOB missense variant.
CONCLUSIONS:
Targeted parallel sequencing of TG-related genes is recommended to define the molecular defect in children presenting with an incidental finding of HyperTG.
2017
- Spectrum of mutations in Italian patients with familial hypercholesterolemia: New results from the LIPIGEN study
[Articolo su rivista]
Pirillo, Angela; Garlaschelli, Katia; Arca, Marcello; Averna, Maurizio; Bertolini, Stefano; Calandra, Sebastiano; Tarugi, Patrizia; Catapano, Alberico L.; Arca, Marcello; Averna, Maurizio; Bertolini, Stefano; Calandra, Sebastiano; Catapano, Alberico Luigi; Tarugi, Patrizia; Pellegatta, Fabio; Angelico, Francesco; Arca, Marcello; Averna, Maurizio; Bartuli, Andrea; Biasucci, Giacomo; Biolo, Gianni; Bonanni, Luca; Bonomo, Katia; Borghi, Claudio; Bossi, Antonio Carlo; Branchi, Adriana; Carubbi, Francesca; Cipollone, Francesco; Citroni, Nadia; Federici, Massimo; Ferri, Claudio; Fiorenza, Anna Maria; Giaccari, Andrea; Giorgino, Francesco; Guardamagna, Ornella; Iannuzzi, Arcangelo; Iughetti, Lorenzo; Lupattelli, Graziana; Mandraffino, Giuseppe; Marcucci, Rossella; Mombelli, Giuliana; Muntoni, Sandro; Pecchioli, Valerio; Pederiva, Cristina; Pipolo, Antonio; Pisciotta, Livia; Pujia, Arturo; Purrello, Francesco; Repetti, Elena; Rubba, Paolo; Sabbà , Carlo; Sampietro, Tiziana; Sarzani, Riccardo; Tagliabue, Milena Paola; Trenti, Chiara; Vigna, Giovanni Battista; Werba, Josà Pablo; Zambon, Sabina; Zenti, Maria Grazia; Montali, Anna; Noto, Davide; Bertolini, Stefano; Calandra, Sebastiano; Fortunato, Giuliana; Grigore, Liliana; Del Ben, Maria; Maranghi, Marianna; Cefalù, A. Baldassarre; Buonuomo, Paola Sabrina; Capra, Maria Elena; Vinci, Pierandrea; D'Addato, Sergio; Galbiati, Stella; Nascimbeni, Fabio; Bucci, Marco; Spagnoli, Walter; Cardolini, Iris; Cervelli, Nazzareno; Emanuela, Colombo; Sun, Vinsin A.; Laviola, Luigi; Bello, Francesca; Chiariello, Giuseppe; Predieri, Barbara; Siepi, Donatella; Saitta, Antonino; Giusti, Betti; Pavanello, Chiara; Lussu, Milena; Prati, Lucia; Banderali, Giuseppe; Balleari, Giulia; Montalcini, Tiziana; Scicali, Roberto; Gentile, Luigi; Gentile, Marco; Suppressa, Patrizia; Sbrana, Francesco; Cocci, Guido; Benso, Andrea; Negri, Emanuele Alberto; Ghirardello, Omar; Lorenzo, Vigo; Zambon, Alberto; Enzo, Bonora; Minicocci, Ilenia; Spina, Rossella; Orlando, Camilla; Tarugi, Patrizia; Di Taranto, Maria Donata; Catapano, Alberico Luigi; Casula, Manuela; Chiodo, Lorenzo; Garlaschelli, Katia; Manzato, Enzo; Tragni, Elena
abstract
Background Familial hypercholesterolemia (FH) is an autosomal dominant disease characterized by elevated plasma levels of LDL-cholesterol that confers an increased risk of premature atherosclerotic cardiovascular disease. Early identification and treatment of FH patients can improve prognosis and reduce the burden of cardiovascular mortality. Aim of this study was to perform the mutational analysis of FH patients identified through a collaboration of 20 Lipid Clinics in Italy (LIPIGEN Study). Methods We recruited 1592 individuals with a clinical diagnosis of definite or probable FH according to the Dutch Lipid Clinic Network criteria. We performed a parallel sequencing of the major candidate genes for monogenic hypercholesterolemia (LDLR, APOB, PCSK9, APOE, LDLRAP1, STAP1). Results A total of 213 variants were detected in 1076 subjects. About 90% of them had a pathogenic or likely pathogenic variants. More than 94% of patients carried pathogenic variants in LDLR gene, 27 of which were novel. Pathogenic variants in APOB and PCSK9 were exceedingly rare. We found 4 true homozygotes and 5 putative compound heterozygotes for pathogenic variants in LDLR gene, as well as 5 double heterozygotes for LDLR/APOB pathogenic variants. Two patients were homozygous for pathogenic variants in LDLRAP1 gene resulting in autosomal recessive hypercholesterolemia. One patient was found to be heterozygous for the ApoE variant p.(Leu167del), known to confer an FH phenotype. Conclusions This study shows the molecular characteristics of the FH patients identified in Italy over the last two years. Full phenotypic characterization of these patients and cascade screening of family members is now in progress.
2017
- Threshold Effects of Circulating Angiopoietin-Like 3 Levels on Plasma Lipoproteins.
[Articolo su rivista]
Fazio, S; Minnier, J; Shapiro, Md; Tsimikas, S; Tarugi, P; Averna, Mr; Arca, M; Tavori, H.
abstract
Abstract
CONTEXT:
Angiopoietin-like 3 (ANGPTL3) deficiency in plasma due to loss-of-function gene mutations results in familial combined hypobetalipoproteinemia type 2 (FHBL2) in homozygotes. However, the lipid phenotype in heterozygotes is much milder and does not appear to relate directly to ANGPTL3 levels. Furthermore, the low-density lipoprotein (LDL) phenotype in carriers of ANGPTL3 mutations is unexplained.
OBJECTIVE:
To determine whether reduction below a critical threshold in plasma ANGPTL3 levels is a determinant of lipoprotein metabolism in FHBL2, and to determine whether proprotein convertase subtilisin kexin type 9 (PCSK9) is involved in determining low LDL levels in this condition.
DESIGN:
We studied subjects from 19 families with ANGPTL3 mutations and subjects with familial combined hypobetalipoproteinemia type 1 (FHBL1) due to truncated apolipoprotein B (apoB) species.
RESULTS:
First, total cholesterol, high-density lipoprotein (HDL) cholesterol, triglycerides, and HDL and LDL particle concentration correlated with plasma ANGPTL3 levels but only when the latter was <25% of normal (<60 ng/dL). Second, the very low-density lipoprotein particle concentration correlated strongly with plasma ANGPTL3 when the latter was <58% of normal. Third, both FHBL1 and FHBL2 subjects showed low levels of mature and LDL-bound PCSK9 and higher levels of its furin-cleaved form. Finally, LDL-bound PCSK9 is protected from cleavage by furin and binds to the LDL receptor more strongly than apoB-free PCSK9.
CONCLUSIONS:
Our results suggest that the hypolipidemic effects of ANGPTL3 mutations in FHBL2 are dependent on a threshold of plasma ANGPTL3 levels, with differential effects on various lipoprotein particles. The increased inactivation of PCSK9 by furin in FHBL1 and FHBL2 is likely to cause increased LDL clearance and suggests novel therapeutic avenues.
2016
- Characterization of a mutant form of human apolipoprotein B (Thr26_Tyr27del) associated with familial hypobetalipoproteinemia
[Articolo su rivista]
Magnolo, A. Lucia; Noto, Davide; Cefalù, Angelo B; Averna, Maurizio; Calandra B., Sebastiano; Yao, Zemin; Tarugi, Patrizia Maria
abstract
We have previously identified a deletion mutant of human apoB [apoB (Thr26_Tyr27del)] in a subject with primary
hypobetalipoproteinemia. The present study determined the effect of Thr26_Tyr27del mutation on apoB
secretion using transfected McA-RH7777 cells. Transient or stable transfection of apoB-48 containing the
Thr26_Tyr27del mutation showed drastically reduced secretion of the mutant as compared to wild-type apoB-
48. No lipoproteins containing the mutant apoB-48 were secreted into the medium. Incubation of transfected
cells in a lipid-rich medium in the presence of cycloheximide showed rapid turnover of cell-associated mutant
apoB-48 as compared to that of wild-type apoB-48. Immunofluorescence experiments showed that the mutant
apoB-48 was mostly localized in the endoplasmic reticulum. Treatment with the proteasomal inhibitor MG132
markedly attenuated the turnover of cell-associated mutant apoB-48, whereas treatment with inhibitors of
autophagosomal/lysosomal function (e.g. 3-MA or ammonium chloride) had no effect. Taken together, these results
indicated that the defective secretion of the Thr26_Tyr27delmutantwas associated with increased intracellular
degradation of apoB through the proteasome-dependent pathway.
2016
- Clinical and genetic features of 3 patients with familial chylomicronemia due to mutations in GPIHBP1 gene
[Articolo su rivista]
Rabacchi, Claudio; D'Addato, Sergio; Palmisano, Silvia; Lucchi, Tiziano; Bertolini, Stefano; Calandra Buonaura, Sebastiano; Tarugi, Patrizia Maria
abstract
BACKGROUND: Familial chylomicronemia is a recessive disorder that may be due to mutations in lipoprotein lipase (LPL) and in other proteins such as apolipoprotein C-II and apolipoprotein A-V (activators of LPL), GPIHBP1 (the molecular platform required for LPL activity on endothelial surface), and LMF1 (a factor required for intracellular formation of active LPL).
METHODS: We sequenced the familial chylomicronemia candidate genes in 2 adult females presenting long-standing hypertriglyceridemia and a history of acute pancreatitis.
RESULTS: Both probands had plasma triglyceride .10 mmol/L but no mutations in the LPL gene. The sequence of the other candidate genes showed that one patient was homozygous for a novel missense mutation p.(Cys83Arg), and the other was homozygous for a previously reported nonsense mutation p.(Cys 89*), respectively, in GPIHBP1. Family screening showed that the hypertriglyceridemic brother of the p.(Cys83Arg) homozygote was also homozygous for this mutation. He had no history of pancreatitis. The p.(Cys83Arg) heterozygous carriers had normal triglyceride levels. The substitution of a cysteine residue in the Ly6 domain of GPIHBP1 is predicted to abolish one of the
disulfide bridges required to maintain the structure of GPIHBP1. The p.(Cys89*) mutation results in a truncated protein devoid of function.
CONCLUSIONS: Both mutant GPIHBP1 proteins are expected to be incapable of transferring LPL from the subendothelial space to the endothelial surface.
2016
- DIAGNOSI MOLECOLARE DELLE IPERTRIGLICERIDEMIE PRIMITIVE ATTRAVERSO “NGS” (NEXT GENERATION SEQUENCING)
[Abstract in Atti di Convegno]
Rabacchi, Claudio; Tenedini, Elena; Bernardis, Isabella; Simone, Maria Luisa; Tagliafico, Enrico; Tarugi, Patrizia Maria
abstract
L’ipertrigliceridemia severa è
una condizione caratterizzata
da elevati livelli di trigliceridi
(TG) superiori a 1000 mg/dl
ed accumulo di chilomicroni a
digiuno. Questa condizione è
rivelata dalla presenza di
plasma lattescente e può essere
secondaria (es. in corso di
diabete scompensato,
sindrome nefrosica grave etc.)
o primitiva su base genetica. La
forma primitiva prende il
nome di Chilomicronemia
Familiare (CF).
Il quadro clinico della CF può
comprendere: coliche
addominali, pancreatiti
ricorrenti, xantomi eruttivi,
lipemia retinalis, ed
epatomegalia. Questo
disordine ha una modalità di
trasmissione autosomica
recessiva ed è dovuto a
mutazioni in uno dei geni
coinvolti nella cascata lipolitica
intravascolare, il processo
attraverso il quale i trigliceridi
trasportati dai chilomicroni e
dalle VLDL sono idrolizzati nel
plasma.
I principali geni candidati
tradizionalmente considerati
sono cinque: il gene LPL che
codifica per l’enzima lipasi
lipoproteica; il gene APOC2
ed il gene APOA5 che
codificano per due
apolipoproteine che svolgono il
ruolo di attivatori della LPL; il
gene GPIHBP1 che codifica la
piattaforma molecolare per la
LPL, ed infine il gene LMF1
che codifica per una proteina
coinvolta nella maturazione
intracellulare della LPL
2016
- Erratum: Corrigendum to “Molecular diagnosis of hypobetalipoproteinemia: An ENID review” (Atherosclerosis (2007) 192(2) (19–27)(S0021915007003280)(10.1016/j.atherosclerosis.2007.05.003))
[Articolo su rivista]
Tarugi, P.; Averna, M.; Di Leo, E.; Cefalu, A. B.; Noto, D.; Magnolo, L.; Cattin, L.; Bertolini, S.; Calandra, S.
abstract
The authors regret an error in the previously reported result concerning the nomenclature of a mutation of APOB gene detected in hypocholesterolemic blood donors. In the text on page e24 in the paragraph 6. ApoB truncations in hypocholeserolemic subjects from the general population we wrote “a carrier of a 6 nucleotide deletion in exon 3 (c.158_163del6) which eliminates two amino acids (threonine at position 26 and tyrosine at position 27 of the mature protein) and introduces an aspartic acid residue with no disruption of the reading frame (Supplementary Table 2 available on line)”. The correct sentence is “a carrier of a six nucleotide deletion in exon 3 (c.158_163del6) which eliminates two amino acids (threonine at position 26 and tyrosine at position 27 of the mature protein) with no disruption of the reading frame (Supplementary Table 2 available on line)”. In the appendix A, Supplementary data, we reported in the first row of Table 2 entitled “Supplementary Table 2. ApoB amino acid changes in hypocholesterolemic blood donors” under the heading “effect on ApoB” the nomenclature Thr26_27delinsAsn. On re-analysis we found that the nomenclature was erroneously reported. The correct designation of the mutation is the following: p.(Thr53_Tyr54del) (Thr26_Tyr27del in the mature protein).
2016
- Homozygous familial hypobetalipoproteinemia: A Turkish case carrying a missense mutation in apolipoprotein B
[Articolo su rivista]
Yilmaz, Berna Seker; Mungan, Neslihan Onenli; Di Leo, Enza; Magnolo, Lucia; Artuso, Lucia; Bernardis, Isabella; Tumgor, Gokhan; Kor, Deniz; Tarugi, Patrizia Maria
abstract
The autosomal co-dominant disorder familial hypobetalipoproteinemia (FHBL) may be due to mutations in the
APOB gene encoding apolipoprotein B (apoB), the main constituent peptide of chylomicrons, very low and low
density lipoproteins. We describe an 11 month-old child with failure to thrive, intestinal lipid malabsorption,
hepatic steatosis and severe hypobetalipoproteinemia, suggesting the diagnosis of homozygous FHBL,
abetalipoproteinemia (ABL) or chylomicron retention disease (CMRD). The analysis of candidate genes showed
that patientwas homozygous for a variant (c.1594 CNT) in the APOB gene causing arginine to tryptophan conversion
at position 505 of mature apoB (Arg505Trp). No mutations were found in a panel of other potential candidate
genes for hypobetalipoproteinemia. In vitro studies showed a reduced secretion of mutant apoB-48 with
respect to the wild-type apoB-48 in transfected McA-RH7777 cells. The Arg505Trp substitution is located in
the βα1 domain of apoB involved in the lipidation of apoB mediated by microsomal triglyceride transfer protein
(MTP), the first step in VLDL and chylomicron formation. The patient's condition improved in response to a low
fat diet supplemented with fat-soluble vitamins. Homozygosity for a rare missense mutation in the βα1 domain
of apoB may be the cause of both severe hypobetalipoproteinemia and intestinal lipid malabsorption.
2016
- Hypercholesterolemia in Childhood: How the Response to Diet could Lead to Diagnosis. Lesson from a Case-Report
[Abstract in Rivista]
Bruzzi, Patrizia; Predieri, Barbara; Madeo, Simona Filomena; Rabacchi, Claudio; Tarugi, Patrizia Maria; Calandra, Sebastiano; Iughetti, Lorenzo
abstract
Sitosterolemia shares clinical and biochemical features with homozygous familial hypercholesterolemia. Nevertheless, it is impressively responsive
to cholesterol-lowering diet. In our report, we demonstrate a rapid reduction of severe hypercholesterolemia in response to dietary
restriction in a young patient leading to the diagnosis of this rare disease. Early identification and treatment may prevent premature atherosclerosis.
2016
- Microsomal triglyceride transfer protein gene mutations in Turkish children: A novel mutation and clinical follow up.
[Articolo su rivista]
Gündüz, M; Özaydın, E; Atar, Mb; Koç, N; Kırsaçlıoğlu, C; Köse, G; Cefalù, Ab; Averna, M; Tarugi, Patrizia Maria
abstract
Abetalipoproteinemia (ABL; OMIM 200100) is a rare autosomal recessive disease that affects the absorption of dietary fats and fat soluble vitamins. Here, we describe the clinical and genetic characteristics of three patients with ABL. Two patients (patients 1 and 2) who were carriers of the c.398-399delAA mutation (previously known mutation) had developmental delay and hepatic steatosis developed at the age of five in patient 1. Patient 3 was the carrier of a novel mutation (g.10886-10902delAAGgtaagtttgtgttg in intron 3 and c.506A>T exon 5) in microsomal triglyceride transfer protein (MTP) gene and had hepatic steatosis.
2016
- Mutation screening of the Otop1 gene in familial benign positional paroxysmal vertigo
[Articolo su rivista]
Monzani, D.; Fancello, T.; Alicandri Ciufelli, M.; Genovese, E.; Tarugi, P.; Cavazza, E. A.; Percesepe, A.
abstract
Objectives: Benign paroxysmal positional vertigo (BPPV) is a sporadic disorder in the vast majority of cases, although a familial, benign, recurrent form, in which the disease segregates in an autosomal dominant fashion has been described. After the evidence for a role of a novel murine gene, Otop1, in knock-out tlt (tilted) and mlh (Mergulhador) mice, lacking the perception of gravity and linear motion and showing a vestibular disorder due to non-syndromic agenesis of both utricular and saccular otoconia, we aimed at verifying the role of the human analogue of the Otop1 gene in BPPV pathogenesis in familial cases of BPPV, collected in our tertiary university referral centre. Methods: Starting in 2007, families with at least two living members thought to have BPPV were considered for inclusion in the present study. The cases were both retrospectively and prospectively identified over the following two years. Results: Seven familial aggregations of BPPV were identified and Otop1 mutation screening showed the presence of a heterozygous mutation in one family, c.1013G> C p.Arg338Pro, which was considered possibly deleterious using the prediction software. It was absent in 100 control alleles, but was also found in two as yet unaffected relatives. Conclusions: The results of a mutation screening of the Otop1 gene in familial cases of BPPV do not support a major role of the gene in the pathogenesis of the disease.
2016
- Novel mutations in the GPIHBP1 gene identified in 2 patients with recurrent acute pancreatitis
[Articolo su rivista]
Ariza, Marıa Jose; Martınez Hernandez, Pedro Luis; Ibarretxe, Daiana; Rabacchi, Claudio; Rioja, Joseh; Grande Aragon, Cristinah; Plana, Nuria; Tarugi, Patrizia Maria; Olivecrona, Gunilla; Calandra, Sebastiano; Valdivielso, Pedro
abstract
BACKGROUND: Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1
(GPIHBP1) has been demonstrated to be essential for the in vivo function of lipoprotein lipase
(LPL), the major triglyceride (TG)-hydrolyzing enzyme involved in the intravascular lipolysis of
TG-rich lipoproteins. Recently, loss-of-function mutations of GPIHBP1 have been reported as the
cause of type I hyperlipoproteinemia in several patients.
METHODS: Two unrelated patients were referred to our Lipid Units because of a severe hypertriglyceridemia
and recurrent pancreatitis. We measured LPL activity in postheparin plasma and serum
ApoCII and sequenced LPL, APOC2, and GPIHBP1.
RESULTS: The 2 patients exhibited very low LPL activity not associated with mutations in LPL
gene or with ApoCII deficiency. The sequence of GPIHBP1 revealed 2 novel point mutations. One
patient (proband 1) was found to be homozygous for a C.A transversion in exon 3 resulting in the
conversion of threonine to lysine at position 80 (p.Thr80Lys). The other patient (proband 2) was found
to be homozygous for a G.T transversion in the third base of the ATG translation initiation codon in
exon 1, resulting in the conversion of methionine to isoleucine (p.Met1Ile).
CONCLUSION: In conclusion, we have identified 2 novel GPIHBP1 missense mutations in 2 unrelated
patients as the cause of their severe hypertriglyceridemia.
2016
- Phenotypic variability in 4 homozygous familial hypercholesterolemia siblings compound heterozygous for LDLR mutations
[Articolo su rivista]
Rabacchi, Claudio; Bigazzi, F; Puntoni, M; Sbrana, F; Sampietro, T; Tarugi, Patrizia Maria; Bertolini, S; Calandra, S.
abstract
BACKGROUND: Homozygous familial hypercholesterolemia is a rare clinical phenotype with a
variable expression, which is characterized by extremely elevated plasma low-density lipoprotein
(LDL), tendon and skin xanthomas, and a progressive atherosclerosis. In 95% of patients, homozygous
familial hypercholesterolemia is due to mutations in low-density lipoprotein receptor
(LDLR) gene, which abolish (receptor-negative) or greatly reduce (receptor-defective) LDLR
function.
OBJECTIVE: The objective of the study was the molecular and phenotypic characterization of 4
siblings with severe hypercholesterolemia.
METHODS: The major LDL-related genes (LDLR, APOB, PCSK9, ANGPTL3, APOE, and
APOC3) were sequenced. LDLR messenger RNA, isolated from leukocytes, was reverse transcribed
and sequenced.
RESULTS: The index cases were 24-year-old identical twin sisters with long-standing tendon
xanthomas and high low-density lipoprotein cholesterol (LDL-C w10 mmol/L) but no coronary
heart disease. They were carriers of 2 LDLR mutations: (1) a previously reported mutation
[p.(G335S)] inherited from the mother who had LDL-C level within normal range; (2) a novel
24 bp deletion in exon 8/intron 8 junction inherited from the hypercholesterolemic (LDL-C
6.1 mmol/L) father. The deletion allele encodes an messenger RNA with a partial deletion of
exon 8, whose translation product has an in-frame deletion of 17 amino acids [p.(Glu380_Gly396-
del)]. Family screening revealed that the 2 siblings of the twin sisters were also compound heterozygotes
but had much lower LDL-C levels (8.2 and 7.1 mmol/L). The sequence of potential
modifying genes showed that the 2 siblings and the mother of the twin sisters were heterozygous
for a rare missense variant of apoB [p.(S2429T)], which might have an LDL-lowering effect.
2016
- Structure-function analyses of microsomal triglyceride transfer protein missense mutations in abetalipoproteinemia and hypobetalipoproteinemia subjects
[Articolo su rivista]
Walsh, Mt; Di Leo, Enza; Okur, I; Tarugi, Patrizia Maria; Hussain, M. M.
abstract
We describe two new hypolipidemic patients with very low plasma triglyceride and apolipoprotein B (apoB) levels with plasma lipid profiles similar to abetalipoproteinemia (ABL) patients. In these patients, we identified two previously uncharacterized missense mutations in the microsomal triglyceride transfer protein (MTP) gene, R46G and D361Y, and studied their functional effects. We also characterized three missense mutations (H297Q, D384A, and G661A) reported earlier in a familial hypobetalipoproteinemia patient. R46G had no effect
on MTP expression or function and supported apoB secretion. H297Q, D384A, and G661A mutants also supported apoB secretion similarly to WT MTP. Contrary to these four missense mutations, D361Y was unable to support apoB secretion. Functional analysis revealed that this mutant was unable to bind protein disulfide isomerase (PDI) or transfer lipids. The negative charge at residue 361 was critical for MTP function as D361E was able to support apoB secretion and transfer lipids. D361Ymost likely disrupts the tightly packedmiddle α-helical region
of MTP, mitigates PDI binding, abolishes lipid transfer activity, and causes ABL. On the other hand, the hypolipidemia in the other two patients was not due to MTP dysfunction. Thus, in this study of five missense mutations spread throughout MTP's three structural domains found in three hypolipidemic patients, we found that four of the mutations did not affect MTP function. Thus, novel mutations that cause severe hypolipidemia probably exist in other genes in these patients, and their recognition may identify novel proteins involved in the synthesis and/or catabolism of plasma lipoproteins.
2015
- Exome Sequencing in Suspected Monogenic Dyslipidemias
[Articolo su rivista]
Stitziel, Nathan O.; Peloso, Gina M.; Abifadel, Marianne; Cefalù, Angelo B.; Fouchier, Sigrid; Motazacker, M. Mahdi; Tada, Hayato; Larach, Daniel B.; Awan, Zuhier; Haller, Jorge F.; Pullinger, Clive R.; Varret, Mathilde; Rabès, Jean Pierre; Noto, Davide; Tarugi, Patrizia Maria; Kawashiri, Masa Aki; Nohara, Atsushi; Yamagishi, Masakazu; Risman, Marjorie; Deo, Rahul; Ruel, Isabelle; Shendure, Jay; Nickerson, Deborah A.; Wilson, James G.; Rich, Stephen S.; Gupta, Namrata; Farlow, Deborah N.; Neale, Benjamin M.; Daly, Mark J.; Kane, John P.; Freeman, Mason W.; Genest, Jacques; Rader, Daniel J.; Mabuchi, Hiroshi; Kastelein, John J. P.; Hovingh, G. Kees; Averna, Maurizio R.; Gabriel, Stacey; Boileau, Catherine; Kathiresan, Sekar
abstract
Abstract
BACKGROUND:
-Exome sequencing is a promising tool for gene mapping in Mendelian disorders. We utilized this technique in an attempt to identify novel genes underlying monogenic dyslipidemias.
METHODS AND RESULTS:
-We performed exome sequencing on 213 selected family members from 41 kindreds with suspected Mendelian inheritance of extreme levels of low-density lipoprotein (LDL) cholesterol (after candidate gene sequencing excluded known genetic causes for high LDL cholesterol families) or high-density lipoprotein (HDL) cholesterol. We used standard analytic approaches to identify candidate variants and also assigned a polygenic score to each individual in order to account for their burden of common genetic variants known to influence lipid levels. In nine families, we identified likely pathogenic variants in known lipid genes (ABCA1, APOB, APOE, LDLR, LIPA, and PCSK9); however, we were unable to identify obvious genetic etiologies in the remaining 32 families despite follow-up analyses. We identified three factors that limited novel gene discovery: (1) imperfect sequencing coverage across the exome hid potentially causal variants; (2) large numbers of shared rare alleles within families obfuscated causal variant identification; and (3) individuals from 15% of families carried a significant burden of common lipid-related alleles, suggesting complex inheritance can masquerade as monogenic disease.
CONCLUSIONS:
-We identified the genetic basis of disease in nine of 41 families; however, none of these represented novel gene discoveries. Our results highlight the promise and limitations of exome sequencing as a discovery technique in suspected monogenic dyslipidemias. Considering the confounders identified may inform the design of future exome sequencing studies.
2015
- Implementation of an NGS-based workflow for BRCA1 and BRCA2 mutation screening
[Abstract in Atti di Convegno]
Artuso, Lucia; Medici, Veronica; Bernardis, Isabella; Tenedini, Elena; Artusi, Valentina; Simone, Maria Luisa; Tarugi, Patrizia Maria; Manfredini, Rossella; Cortesi, Laura; Tagliafico, Enrico
abstract
probability to develop familiar breast cancer. To detect BRCA1/2 germline mutations we developed a next-generation sequencing (NGS) routine dia- gnostic workflow, based on the Ion Torrent PGMTM System platform. The Ion AmpliSeqTM BRCA1 and BRCA2 Community Panel was handled with a semi- automatized procedure for multiplex PCR-based library preparation and se- quencing. Data analysis required the implementation of a custom designed bioinformatic pipeline for sequences alignment and for the identification, annotation and filtration of genetic variants. Sanger sequencing was perfor- med to validate candidate mutations, and to re-sequence amplicons having low NGS coverage (<50 reads per amplicon). Negative samples were ana- lyzed using the BRCA HP Kit (Multiplicom) for an effective homopolymeric stretches detection. This workflow together with the potentiality of our bio- informatic pipeline was blindly tested and validated onto a small cohort of patients previously Sanger sequenced, fine-tuning the parameter settings and resulting in a sensitivity of 100% in variant detection. Subsequently, 244 patients were analyzed thus confirming the need of a double check for the homopolymeric stretches with both NGS sequencing and BRCA HP Kit. The NGS-based workflow here proposed was able to decrease the overall
2015
- Microsomal Triglyceride Transfer Protein Transfers and Determines Plasma Concentrations of Ceramide and Sphingomyelin but Not Glycosylceramide
[Articolo su rivista]
Iqbal, Jahangir; Walsh, Meghan T.; Hammad, Samar M.; Cuchel, Marina; Tarugi, Patrizia Maria; Hegele, Robert A.; Davidson, Nicholas O.; Rader, Daniel J.; Klein, Richard L.; Hussain, M. Mahmood
abstract
Sphingolipids, a large family of bioactive lipids, are implicated in stress responses, differentiation, proliferation, apoptosis, and other physiological processes. Aberrant plasma levels of sphingolipids contribute to metabolic disease, atherosclerosis, and insulin resistance. They are fairly evenly distributed in high density and apoB-containing lipoproteins (B-lps). Mechanisms involved in the transport of sphingolipids to the plasma are unknown. Here, we investigated the role of microsomal triglyceride transfer protein (MTP), required for B-lp assembly and secretion, in sphingolipid transport to the plasma. Abetalipoproteinemia patients with deleterious mutations in MTP and absence of B-lps had significantly lower plasma ceramide and sphingomyelin but normal hexosylceramide, lactosylceramide, and different sphingosines compared with unaffected controls. Furthermore, similar differential effects on plasma sphingolipids were seen in liver- and intestine-specific MTP knock-out (L,I-Mttp(-/-)) mice, suggesting that MTP specifically plays a role in the regulation of plasma ceramide and sphingomyelin. We hypothesized that MTP deficiency may affect either their synthesis or secretion. MTP deficiency had no effect on ceramide and sphingomyelin synthesis but reduced secretion from primary hepatocytes and hepatoma cells. Therefore, MTP is involved in ceramide and sphingomyelin secretion but not in their synthesis. We also found that MTP transferred these lipids between vesicles in vitro. Therefore, we propose that MTP might regulate plasma ceramide and sphingomyelin levels by transferring these lipids to B-lps in the liver and intestine and facilitating their secretion.
2015
- Novel Abetalipoproteinemia Missense Mutation Highlights the Importance of the N-Terminal β-Barrel in Microsomal Triglyceride Transfer Protein Function
[Articolo su rivista]
Walsh, Meghan T.; Iqbal, Jahangir; Josekutty, Joby; Soh, James; Di Leo, Enza; Özaydin, Eda; Gündüz, Mehmet; Tarugi, Patrizia Maria; Hussain, M. Mahmood
abstract
The use of microsomal triglyceride transfer protein (MTP) inhibitors is limited to severe hyperlipidemias because of associated hepatosteatosis and gastrointestinal adverse effects. Comprehensive knowledge about the structure-function of MTP might help design new molecules that avoid steatosis. Characterization of mutations in MTP causing abetalipoproteinemia has revealed that the central α-helical and C-terminal β-sheet domains are important for protein disulfide isomerase binding and lipid transfer activity. Our aim was to identify and characterize mutations in the N-terminal domain to understand its function.
2015
- Spectrum of mutations of the LPL gene identified in Italy in patients with severe hypertriglyceridemia
[Articolo su rivista]
Rabacchi, Claudio; Pisciotta, Livia; Cefalù, Angelo B.; Noto, Davide; Fresa, Raffaele; Tarugi, Patrizia Maria; Averna, Maurizio; Bertolini, Stefano; CALANDRA BUONAURA, Sebastiano
abstract
Monogenic hypertriglyceridemia (HTG) may result from mutations in some genes which impair the intravascular lipolysis of triglyceride (TG)-rich lipoproteins mediated by the enzyme Lipoprotein lipase (LPL). Mutations in the LPL gene are the most frequent cause of monogenic HTG (familial chylomicronemia) with recessive transmission.
2015
- The Janus-faced manifestations of homozygous familial hypobetalipoproteinemia due to apolipoprotein B truncations
[Articolo su rivista]
DI LEO, Enza; Eminoglu, Tuba; Magnolo, Antonia Lucia; Bolkent, Musa Gökalp; Tümer, Leyla; Okur, Ilyas; Tarugi, Patrizia Maria
abstract
Familial hypobetalipoproteinemia is a codominant disorder characterized by low plasma levels of low-density lipoprotein cholesterol and apolipoprotein B (apoB), which in ∼50% of the cases is due to mutations in APOB gene. In most cases, these mutations cause the formation of truncated apoBs of various sizes, which have a reduced capacity to bind lipids and form lipoprotein particles. Here, we describe 2 children with severe hypobetalipoproteinemia found to be homozygous for novel APOB gene mutations. The first case (HBL-201) was an asymptomatic 13-year-old boy incidentally found to have slightly elevated serum transaminases associated with hepatic steatosis. He was homozygous for a truncated apoB (2211 amino acids, apoB-48.74) whose size is similar to that of wild-type apoB-48 (2152 amino acids) produced by the intestine. ApoB-48.74 is expected to be incorporated into chylomicrons in the intestine but might have a reduced capacity to form secretion-competent very low-density lipoprotein in the liver. The second patient (HBL-96) was a 6-month-old girl suspected to have abetalipoproteinemia, for the presence of chronic diarrhea, failure to thrive, extremely severe hypobetalipoproteinemia, and low plasma levels of vitamin E and vitamin A. She was homozygous for a nonsense mutation (Gln513*) resulting in a short truncated apoB (apoB-11.30), which is not secreted into the plasma. In this patient, the impaired chylomicron formation is responsible for the severe clinical manifestations and growth retardation. In homozygous familial hypobetalipoproteinemia, the capacity of truncated apoBs to form chylomicrons is the major factor, which affects the severity of the clinical manifestations.
2014
- Flow-mediated dilation, carotid wall thickness and HDL function in subjects with hyperalphalipoproteinemia
[Articolo su rivista]
Vigna, G. B; Satta, E; Bernini, F; Boarini, S; Bosi, C; Giusto, L; Pinotti, Elisa; Tarugi, Patrizia Maria; Vanini, A; Volpato, S; Zimetti, F; Zuliani, G; Favari, E.
abstract
BACKGROUND AND AIMS:
The relationships between very high plasma HDLc and subclinical atherosclerosis are still a matter of debate.
METHODS AND RESULTS:
Twenty subjects with primary hyperalphalipoproteinemia (HAL, with HDLc in the highest 10th percentile and absence of overt secondary causes of this condition), aged 30-65 years, were compared with 20 age and sex-matched controls. Lipid determination, lipoprotein particle distribution (Lipoprint(®)), Cholesterol Efflux Capacity (CEC), plasma adhesion molecule, analyses of CETP, SRB1 and LIPG genes and of different markers of subclinical vascular disease (ankle-brachial index, ABI; carotid intima-media thickness, cIMT; brachial-artery flow mediated dilation, FMD) were performed. Fasting HDLc levels were 40 mg/dl higher in HAL subjects while LDLc concentration was comparable to control group. CETP gene analysis in HAL subjects identified one novel rare Single Nucleotide Polymorphism (SNP, Asp131Asn), possibly damaging, while the common SNP p.Val422Ile was highly prevalent (50% vs. 27.4% in a control population). No rare mutations associated with HAL were found in SR-B1 and LIPG genes. Polyacrylamide gel electrophoresis in HAL subjects disclosed larger and more buoyant HDL particles than in controls, while LDL profile was much more similar. ABI, cIMT and arterial plaques did not differ in cases and controls and the two groups showed comparable FMD at brachial artery examination. Similarly, ABCA1 and ABCG1 HDL-mediated CEC, the most relevant for atheroprotection, did not discriminate between the groups and only ABCG1 pathway seemed somewhat related to arterial reactivity.
CONCLUSIONS:
HDL dimension, function and genetics seem scarcely related to subclinical atherosclerosis and vascular reactivity in middle-aged HAL subjects.
2013
- A novel APOB mutation identified by exome sequencing cosegregates with steatosis, liver cancer, and hypocholesterolemia.
[Articolo su rivista]
Cefalù, Ab; Pirruccello, Jp; Noto, D; Gabriel, S; Valenti, V; Gupta, N; Spina, R; Tarugi, Patrizia Maria; Kathiresan, S; Averna, M. R.
abstract
Abstract
OBJECTIVE:
In familial hypobetalipoproteinemia, fatty liver is a characteristic feature, and there are several reports of associated cirrhosis and hepatocarcinoma. We investigated a large kindred in which low-density lipoprotein cholesterol, fatty liver, and hepatocarcinoma displayed an autosomal dominant pattern of inheritance.
APPROACH AND RESULTS:
The proband was a 25-year-old female with low plasma cholesterol and hepatic steatosis. Low plasma levels of total cholesterol and fatty liver were observed in 10 more family members; 1 member was affected by liver cirrhosis, and 4 more subjects died of either hepatocarcinoma or carcinoma on cirrhosis. To identify the causal mutation in this family, we performed exome sequencing in 2 participants with hypocholesterolemia and fatty liver. Approximately 22 400 single nucleotide variants were identified in each sample. After variant filtering, 300 novel shared variants remained. A nonsense variant, p.K2240X, attributable to an A>T mutation in exon 26 of APOB (c.6718A>T) was identified, and this variant was confirmed by Sanger sequencing. The gentotypic analysis of 16 family members in total showed that this mutation segregated with the low cholesterol trait. In addition, genotyping of the PNPLA3 p.I148M did not show significant frequency differences between carriers and noncarriers of the c.6718A>T APOB gene mutation.
CONCLUSIONS:
We used exome sequencing to discover a novel nonsense mutation in exon 26 of APOB (p.K2240X) responsible for low cholesterol and fatty liver in a large kindred. This mutation may also be responsible for cirrhosis and liver cancer in this family.
2013
- Clinical characteristics and plasma lipids in subjects with familial combined hypolipidemia: a pooled analysis.
[Articolo su rivista]
Minicocci, I; Santini, S; Cantisani, V; Stitziel, N; Kathiresan, S; Arroyo, Ja; Martí, G; Pisciotta, L; Noto, D; Cefalù, Ab; Maranghi, M; Labbadia, G; Pigna, G; Pannozzo, F; Ceci, F; Ciociola, E; Bertolini, S; CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Averna, M; Arca, M.
abstract
Angiopoietin-like 3 (ANGPTL3) regulates lipoprotein metabolism by modulating extracellular lipases. Loss-of function mutations in ANGPTL3 gene cause familial combined hypolipidemia (FHBL2). The mode of inheritance and hepatic and vascular consequences of FHBL2 have not been fully elucidated. To get further insights on these aspects, we reevaluated the clinical and the biochemical characteristics of all reported cases of FHBL2. One hundred fifteen FHBL2 individuals carrying 13 different mutations in the ANGPTL3 gene (14 homozygotes, 8 compound heterozygotes, and 93 heterozygotes) and 402 controls were considered. Carriers of two mutant alleles had undetectable plasma levels of ANGPTL3 protein, whereas heterozygotes showed a reduction ranging from 34% to 88%, according to genotype. Compared with controls, homozygotes as well as heterozygotes showed a significant reduction of all plasma lipoproteins, while no difference in lipoprotein(a) [Lp(a)] levels was detected between groups. The prevalence of fatty liver was not different in FHBL2 subjects compared with controls. Notably, diabetes mellitus and cardiovascular disease were absent among homozygotes. FHBL2 trait is inherited in a codominant manner, and the lipid-lowering effect of two ANGPTL3 mutant alleles was more than four times larger than that of one mutant allele. No changes in Lp(a) were detected in FHBL2. Furthermore, our analysis confirmed that FHBL2 is not associated with adverse clinical sequelae. The possibility that FHBL2 confers lower risk of diabetes and cardiovascular disease warrants more detailed investigation.
2013
- Familial combined hypolipidemia due to mutations in the ANGPTL3 gene
[Articolo su rivista]
Calandra, S.; Tarugi, P.; Averna, M.; Bertolini, S.
abstract
The role of ANGPTL3 in lipoprotein metabolism emerged from studies in a mutant mouse strain characterized by severe hypotriglyceridemia and carrying a loss-of-function (LOF) mutation of the ANGPTL3 gene. ANGPTL3 was found to inhibit lipoprotein lipase and endothelial lipase. Genome-wide association studies in humans demonstrated the association of ANGPTL3 variants with plasma triglyceride levels and LOF mutations of ANGPTL3 were found in hypotriglyceridemic subjects in population studies. Recently, individuals originally classified as affected by familial hypobetalipoproteinemia were found to be homozygotes/compound heterozygotes for rare LOF mutations of ANGPTL3. They show a striking reduction of all lipoprotein classes (VLDL, LDL and HDL), a condition defined as familial combined hypolipidemia. This disorder, transmitted as a recessive trait, does not seem to be associated with specific clinical manifestations, such as premature atherosclerosis or fatty liver disease. © 2013 Future Medicine Ltd.
2013
- Familial hypobetalipoproteinemia: analysis of three Spanish cases with two new mutations in the APOB gene.
[Articolo su rivista]
Martín Morales, R; García Díaz, Jd; Tarugi, Patrizia Maria; González Santos, P; Saavedra Vallejo, P; Magnolo, L; Mesa Latorre, Jm; di Leo, E; Valdivielso, P.
abstract
Abstract
Extremely low LDL-cholesterol concentrations are very unusual and generally related with comorbidities accompanying malnutrition. Less frequently low LDL-cholesterol levels result from mutations in the APOB, PCSK9, ANGPTL3, SAR1B and MTTP genes (primary hypobetalipoproteinemia). We investigated three patients with plasma LDL-cholesterol levels below the fifth percentile of the Spanish population. We recorded data on demographic and anthropometric characteristics, life style habits, physical examination, liver ultrasound and lipid and lipoprotein levels, in the probands and their first-degree relatives. Secondary causes of hypocholesterolemia were ruled out by clinical study, complementary tests and follow-up. The APOB, MTTP and SAR1B genes were sequenced. Patients were found to be heterozygotes for point mutations located in the exon 26 of the APOB gene. One patient, with fatty liver, carried a previously described mutation (c.7600C>T) (Arg2507X), causing the formation of truncated Apo B-55.25. The other two mutations producing truncations are new. One asymptomatic patient carried the Arg3672X (Apo B-80.93) and the other with fatty liver and steatorrhea carried the Ser2184fsVal2193X (Apo B-48.32). Our study reinforces the concept that in the heterozygous carriers of truncated Apo Bs, the clinical manifestations of FHBL are dependent on the size of the truncations.
2013
- Novel mutations in SAR1B and MTTP genes in Tunisian children with chylomicron retention disease and abetalipoproteinemia.
[Articolo su rivista]
Magnolo, Antonia Lucia; Najah, M; Fancello, Tatiana; Di Leo, E; Pinotti, Elisa; Brini, I; Gueddiche, Nm; CALANDRA BUONAURA, Sebastiano; Slimene, Nm; Tarugi, Patrizia Maria
abstract
Monogenic hypobetalipoproteinemias include three disorders: abetalipoproteinemia (ABL) and chylomicron retention disease (CMRD) with recessive transmission and familial hypobetalipoproteinemia (FHBL) with dominant transmission. We investigated three unrelated Tunisian children born from consanguineous marriages, presenting hypobetalipoproteinemia associated with chronic diarrhea and retarded growth. Proband HBL-108 had a moderate hypobetalipoproteinemia, apparently transmitted as dominant trait, suggesting the diagnosis of FHBL. However, she had no mutations in FHBL candidate genes (APOB, PCSK9 and ANGPTL3). The analysis of MTTP gene was also negative, whereas SAR1B gene resequencing showed that the patient was homozygous for a novel mutation (c.184G>A), resulting in an amino acid substitution (p.Glu62Lys), located in a conserved region of Sar1b protein. In the HBL-103 and HBL-148 probands, the severity of hypobetalipoproteinemia and its recessive transmission suggested the diagnosis of ABL. The MTTP gene resequencing showed that probands HBL-103 and HBL-148 were homozygous for a nucleotide substitution in the donor splice site of intron 9 (c.1236+2T>G) and intron 16 (c.2342+1G>A) respectively. Both mutations were predicted in silico to abolish the function of the splice site. In vitro functional assay with splicing mutation reporter MTTP minigenes showed that the intron 9 mutation caused the skipping of exon 9, while the intron 16 mutation caused a partial retention of this intron in the mature mRNA. The predicted translation products of these mRNAs are non-functional truncated proteins.
The diagnosis of ABL and CMRD should be considered in children born from consanguineous parents, presenting chronic diarrhea associated with hypobetalipoproteinemia.
2012
- A 54-year-old diabetic man with low serum cholesterol
[Relazione in Atti di Convegno]
Turk, U.; Basol, G.; Barutcuoglu, B.; Sahin, F.; Habif, S.; Tarugi, P.; Bayindir, O.
abstract
2012
- A 54-year-old diabetic man with low serum cholesterol.
[Articolo su rivista]
Turk, U; Basol, G; Barutcuoglu, B; Sahin, F; Habif, S; Tarugi, Patrizia Maria; Bayindir, O.
abstract
No abstract available
2012
- Characterization of Three Kindreds with Familial Combined Hypolipidemia Due to Loss of Function Mutations of ANGPTL3.
[Articolo su rivista]
Pisciotta, L; Favari, E; Magnolo, Antonia Lucia; Simonelli, S; Adorni, Mp; Sallo, R; Fancello, Tatiana; Zavaroni, I; Ardigò, D; Bernini, F; Calabresi, L; Franceschini, G; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Bertolini, S.
abstract
BACKGROUND: -Angiopoietin-like protein 3 (ANGPTL3) affects lipid metabolism by inhibiting the activity of lipoprotein and endothelial lipases. Angptl3 knock out mice have a marked hypolipidemia and heterozygous carriers of ANGPLT3 loss of function (LOF) mutations were found among individuals in the lowest quartile of plasma triglyceride (TG) in population studies. Recently four related individuals with primary hypolipidemia were found to be compound heterozygotes for ANGPTL3 LOF mutations.METHODS AND RESULTS: -We resequenced ANGPTL3 in four members of three kindred originally identified for very low LDL-C and HDL-C levels (0.97±0.16 and 0.56±0.20 mmol/L), in whom no mutations of known candidate genes for monogenic hypobeta- and hypoalpha-lipoproteinemia had been detected. These subjects were found to be homozygous or compound heterozygous for ANGPTL3 LOF mutations (p.G400VfsX5, p.I19LfsX22/p.N147X), associated with the absence of ANGPTL3 in plasma. They had reduced plasma levels of TG containing lipoproteins and of LpA-I and preβ-HDL particles. In addition, their apoB-depleted sera had a reduced capacity to promote cell cholesterol efflux through the various pathways (ABCA1-, SR-BI- and ABCG1-mediated efflux). However, these subjects had no clinical evidence of accelerated atherosclerosis. Heterozygous carriers of the ANGPTL3 mutations had low plasma ANGPTL3, moderately reduced LDL-C (2.52±0.38 mmol/L) but normal plasma HDL-C.CONCLUSIONS: -Complete ANGPTL3 deficiency caused by LOF mutations of ANGPTL3 is associated with a recessive hypolipidemia characterized by a reduction of apolipoprotein B and apolipoprotein A-I containing lipoproteins, changes in HDL subclasses and reduced cholesterol efflux potential of serum. Partial ANGPTL3 deficiency is associated only with a moderate reduction of LDL.
2012
- Lipid and apoprotein composition of HDL in partial or complete CETP deficiency.
[Articolo su rivista]
Niesor, Ej; von der Mark, E; Calabresi, L; Averna, M; Cefalù, Ab; Tarugi, Patrizia Maria; Nilsson, P; Dernick, G.
abstract
Hyperalphalipoproteinemia, as observed in patients who are either homozygous or heterozygous for cholesteryl ester transfer protein (CETP) deficiency, has been shown to be associated with striking changes in apolipoprotein size distribution, namely, of high-density lipoprotein (HDL) and HDL-like particles. We compared the effect of varying degrees of CETP activity on the HDL apolipoprotein profile in Caucasian CETP-deficient subjects and following pharmacological decrease in CETP activity, using Size Exclusion Chromatography followed by Reverse Phase Protein Array (SEC RPA). The main HDL-associated apolipoproteins (Apo), i.e. ApoA-I, ApoA-II, ApoC-I, and ApoC-III, co-eluted with the HDL peak. The presence of a HDL-like peak migrating between the ApoB-LDL and ApoA-I-HDL was identified in a Caucasian patient with homozygosity for a point mutation in exon 2 of the CETP gene (c.109 C > T) resulting in a premature termination codon (R37X) and complete CETP deficiency. This HDL-like peak was not observed either in healthy volunteers treated with the CETP modulator dalcetrapib, patients heterozygous for the same mutation, or in patients heterozygous with G165X mutations. SEC RPA offers the possibility to investigate the distribution of a large number of apolipoproteins simultaneously under non-denaturing separation in normal and dyslipidemic subjects. This is only limited by the availability of antibodies against specific apolipoproteins to be investigated.
2012
- Novel missense variants in LCAT and APOB genes in an Italian kindred with familial lecithin:cholesterol acyltransferase deficiency and hypobetalipoproteinemia.
[Articolo su rivista]
Conca, P; Pileggi, S; Simonelli, S; Boer, E; Boscutti, G; Magnolo, Antonia Lucia; Tarugi, Patrizia Maria; Penco, S; Franceschini, G; Calabresi, L; Gomaraschi, M.
abstract
BACKGROUND:
Lecithin:cholesterol acyltransferase (LCAT) is responsible for cholesterol esterification in plasma. Mutations of LCAT gene cause familial LCAT deficiency, a metabolic disorder characterized by hypoalphalipoproteinemia. Apolipoprotein B (apoB) is the main protein component of very-low-density lipoproteins and low-density lipoprotein (LDL). Mutations of APOB gene cause familial hypobetalipoproteinemia, a codominant disorder characterized by low plasma levels of LDL cholesterol and apoB.
OBJECTIVE:
This was a genetic and biochemical analysis of an Italian kindred with hypobetalipoproteinemia whose proband presented with hypoalphalipoproteinemia and severe chronic kidney disease.
METHODS:
Plasma lipids and apolipoproteins, cholesterol esterification, and high-density lipoprotein (HDL) subclass distribution were analyzed. LCAT and APOB genes were sequenced.
RESULTS:
The proband had severe impairment of plasma cholesterol esterification and high preβ-HDL content. He was heterozygote for the novel LCAT P406L variant, as were two other family members. The proband's wife and children presented with familial hypobetalipoproteinemia and were heterozygotes for the novel apoB H1401R variant. Cholesterol esterification rate of apoB H1401R carriers was reduced, likely attributable to the low amount of circulating LDL. After renal transplantation, proband's lipid profile, HDL subclass distribution, and plasma cholesterol esterification were almost at normal levels, suggesting a mild contribution of the LCAT P406L variant to his pretransplantation severe hypoalphalipoproteinemia and impairment of plasma cholesterol esterification.
CONCLUSION:
LCAT P406L variant had a mild effect on lipid profile, HDL subclass distribution, and plasma cholesterol esterification. ApoB H1401R variant was identified as possible cause of familial hypobetalipoproteinemia and resulted in a reduction of cholesterol esterification rate.
2012
- Prevalence of ANGPTL3 and APOB Gene Mutations in Subjects With Combined Hypolipidemia.
[Articolo su rivista]
D., Noto; A. B., Cefalù; V., Valenti; F., Fayer; E., Pinotti; M., Ditta; R., Spina; G., Vigna; P., Yue; S., Kathiresan; Tarugi, Patrizia Maria; M. R., Averna
abstract
Objective—Mutations of the ANGPTL3 gene have been associated with a novel form of primary hypobetalipoproteinemia, the combined hypolipidemia (cHLP), characterized by low total cholesterol and low HDL-cholesterol levels. The aim of this work is to define the role of ANGPTL3 gene as determinant of the combined hypolipidemia phenotype in 2 large cohorts of 913 among American and Italian subjects with primary hypobetalipoproteinemia (total cholesterol 5th percentile).Methods and Results—The combined hypolipidemia cut-offs were chosen according to total cholesterol and HDL-cholesterol levels reported in the ANGPTL3 kindred described to date: total cholesterol levels, 2nd percentile and HDL-cholesterol, levels 2nd decile. Seventy-eight subjects with combined hypolipidemia were analyzed for ANGPTL3 and APOB genes. We identified nonsense and/or missense mutations in ANGPTL3 gene in 8 subjects; nomutations of the APOB gene were found. Mutated ANGPTL3 homozygous/compound heterozygous subjects showed amore severe biochemical phenotype compared to heterozygous or ANGPTL3 negative subjects, although ANGPTL3 heterozygotes did not differ from ANGPTL3 negative subjects.Conclusion—these results demonstrated that in a cohort of subjects with severe primary hypobetalipoproteinemia the prevalence of ANGPTL3 gene mutations responsible for a combined hypolipidemia phenotype is about 10%, whereas mutations of APOB gene are absent.
2011
- Altered mRNA splicing in lipoprotein disorders.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Bertolini, S.
abstract
PURPOSE OF REVIEW: To review recent publications concerning the functional assessment on pre-mRNA splicing of genomic variants found in some monogenic dyslipidemias. Examples are derived from familial hypercholesterolemia,familial HDL deficiency/Tangier disease and familial hypobetalipoproteinemia.RECENT FINDINGS: About 5-10% of genomic variants found in familial hypercholesterolemia,FHD/Tangier disease and familial hypobetalipoproteinemia are located in the introns of the candidate genes and are classified as splicing mutations. Although variants affecting highly conserved GT/AG dinucleotides at the splice sites are likely to be pathogenic,it is difficult to predict the effects of variants located deep in the introns. Algorithms were developed to predict the effect of these variants and to provide the rationale for functional studies. Combined in-silico and wet bench analysis revealed that some intronic variants classified as pathogenic have no effect,whereas others generated abnormal transcripts. Nucleotide substitutions at the 5' and the 3' of exons might change the splice site consensus sequence,causing splicing defects. Rare silent mutations were identified which create new splice sites within exons,with the consequent production of abnormal transcripts.SUMMARY: Intronic variants,even if located deep in introns,as well as exonic variants could affect splicing with the formation of abnormal transcripts encoding structurally abnormal proteins
2011
- Hypobetalipoproteinemia: genetics, biochemistry, and clinical spectrum.
[Articolo su rivista]
Tarugi, Patrizia Maria; M., Averna
abstract
Hypobetalipoproteinemias (HBL) represent a heterogeneous group of disorders characterized by reduced plasma levels of total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C) and apolipoprotein B (apoB) below the 5th percentile of the distribution in the population. HBL are defined as primary or secondary according to the underlying causes. Primary monogenic HBL are caused by mutations in several known genes (APOB, PCSK9, MTP, SARA2) or mutations in genes not yet identified. Familial hypobetalipoproteinemia (FHBL) is the most frequent monogenic form of HBL with a dominant mode of inheritance. It may be due to loss-of-function mutations in APOB or, less frequently, in PCSK9 genes. The rare recessive forms of primary monogenic HBL are represented by abetalipoproteinemia (ABL) and chylomicron retention disease (CMRD) due to mutations in MTP and SARA2 genes, respectively. The clinical phenotype of heterozygous FHBL is usually mild, being frequently characterized by fatty liver. The clinical phenotype of homozygous FHBL, ABL, and CMRD is usually severe being characterized by intestinal lipid malabsorption and fat-soluble vitamin deficiency. Secondary HBL are due to several nongenetic factors such as diet, drugs, and disease-related conditions. The aim of this review is to discuss the biochemistry, genetics, and clinical spectrum of HBL and to provide a clinical and laboratory diagnostic algorithm.
2011
- Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Speedy, He; Dean, Af; Bertolini, S; Shoulders, C. C.
abstract
This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.
2011
- Plasma non-cholesterol sterols in primary hypobetalipoproteinemia.
[Articolo su rivista]
D., Noto; A. B., Cefalù; G., Barraco; F., Fayer; M., Minà; P., Yue; Tarugi, Patrizia Maria; G., Schonfeld; M. R., Averna
abstract
Primary hypobetalipoproteinemia (pHBL) is characterized by plasma cholesterol levels <5th percentile of a population distribution. Plasma non-cholesterol sterols (NCS) are markers of cholesterol liver synthesis and intestinal absorption. Plasma NCS were measured in 111 pHBL subjects, 108 low cholesterol (LC) and 253 normal cholesterol (NC) controls to gain information on cholesterol metabolism in pHBL, and to assess whether NCS measurements may aid in distinguishing pHBL from LC controls. pHBL subjects compared with LC controls were characterized by increased cholesterol absorption (campesterol/TC) while the synthesis (lathosterol/TC) was not increased. The analysis of pHBL subjects divided by gene defect showed a high campesterol/TC ratio in familial HBL (FHBL) carriers of apolipoproteinB (ApoB) truncations longer than ApoB48 and in FHBL without known gene defect ("not linked"). One not linked kindred was characterized by an increase of the 7-dehydrocholesterol/latho ratio. In a discriminant analysis plasma NCS did not improve the power of TC levels to distinguish FHBL from LC controls. In conclusion, increased cholesterol absorption was found in FHBL subjects harbouring truncations of ApoB>ApoB48, and FHBL harbouring as yet unknown molecular defects. Not linked FHBL kindred are not homogeneous in terms of plasma NCS levels. NCS cannot replace genetic HBL analysis.
2010
- Abetalipoproteinemia in an infant with severe clinical phenotype and a novel mutation
[Articolo su rivista]
N., Uslu; F., Gürakan; A., Yüce; H., Demir; Tarugi, Patrizia Maria
abstract
Abetalipoproteinemia (ABL) is a rare autosomal disorder characterized by extremely low levels of plasma lipids and apolipoprotein B (apoB) with a variable phenotype. Mutations in the MTP gene encoding the microsomal triglyceride transfer protein (MTP) cause the disease. A five-month-old boy, born from consanguineous parents, with chronic diarrhea and severe malnutrition had extremely low plasma lipids and apoB levels suggesting the diagnosis of ABL. He was not responsive to treatment with low-fat diet and fat-soluble vitamins and died at 13 months of age with severe malnutrition. Analysis of the MTP gene showed that he was homozygous for a two nucleotide deletion in exon 4 (c.398-399delAA) expected to cause a frameshift in the mRNA leading to a premature termination codon. The normolipidemic proband's parents were found to be heterozygous for the mutation. This observation underscores that in some cases, ABL can be extremely severe from early post-natal life and poorly responsive to treatment.
2010
- Nonsynonymous mutations within APOB in human familial hypobetalipoproteinemia: evidence for feedback inhibition of lipogenesis and postendoplasmic reticulum degradation of apolipoprotein B.
[Articolo su rivista]
Zhong, S; Magnolo, Al; Sundaram, M; Zhou, H; Yao, Ef; Di Leo, E; Loria, Paola; Wang, S; Bamji Mirza, M; Wang, L; Mcknight, Cj; Figeys, D; Wang, Y; Tarugi, Patrizia Maria; Yao, Z.
abstract
Five nontruncating missense APOB mutations, namely A31P, G275S, L324M, G912D, and G945S, were identified in heterozygous carriers of familial hypobetalipoproteinemia (FHBL) in the Italian population. To test that the FHBL phenotype was a result of impaired hepatic secretion of mutant apoB proteins, we performed transfection studies using McA-RH7777 cells stably expressing wild type or mutant forms of human apolipoprotein B-48 (apoB-48). All mutant proteins displayed varied impairment in secretion, with G912D the least affected and A31P barely secreted. Although some A31P was degraded by proteasomes, a significant proportion of it (although inappropriately glycosylated) escaped endoplasmic reticulum (ER) quality control and presented in the Golgi compartment. Degradation of the post-ER A31P was achieved by autophagy. Expression of A31P also decreased secretion of endogenous apoB and triglycerides, yet the impaired lipoprotein secretion did not lead to lipid accumulation in the cells or ER stress. Rather, expression of genes involved in lipogenesis was down-regulated, including liver X receptor alpha, sterol regulator element-binding protein 1c, fatty acid synthase, acetyl-CoA carboxylase 1, stearoyl-CoA desaturase 1, and lipin-1. These results suggest that feedback inhibition of hepatic lipogenesis in conjunction with post-ER degradation of misfolded apoB proteins can contribute to reduce fat accumulation in the FHBL liver.
2010
- Novel LMF1 nonsense mutation in a patient with severe hypertriglyceridemia (Journal of Clinical Endocrinology and Metabolism (2009) 94, (4584-4590))
[Articolo su rivista]
Cefalu, A. B.; Noto, D.; Arpi, M. L.; Yin, F.; Spina, R.; Hilden, H.; Barbagallo, C. M.; Carroccio, A.; Tarugi, P.; Squatrito, S.; Vigneri, R.; Taskinen, M. -R.; Peterfy, M.; Averna, M. R.
abstract
2010
- Novel mutation in the APOB Gene (Apo B-15.56): A case report
[Articolo su rivista]
Bove, M.; Carnevali, L.; Cicero, A. F. G.; Tarugi, P.; Gaddi, A. V.
abstract
Familial hypobetalipoproteinemia (FHBL) is a rare co-dominant genetic disorder characterized by decrease of plasma low density lipoprotein-cholesterol (LDL-c) or apolipoprotein B (Apo-B) equal to or less than the 5th percentile for the population. We describe a 48-year-old male who presented with fatty liver disease (FLD), insulin resistance (IR), obesity and hypertension. Our patient thus met the latest diagnostic criteria of the metabolic syndrome (MS) proposed by the Adult Treatment Panel and the International Diabetes Federation. However, he had very low plasma concentration of LDL-c and Apo-B. DNA sequencing showed that he and two first-degree relatives affected by obesity and mild IR were heterozygous for a single nucleotide deletion on exon 15 of the APOB gene, which was predicted to form a truncated Apo-B designated Apo B-15.56.
2010
- Pseudoxanthoma elasticum and familial hypercholesterolemia: A deleterious combination of cardiovascular risk factors
[Articolo su rivista]
Pisciotta, L; Tarugi, Patrizia Maria; Borrini, C; Bellocchio, A; Fresa, R; Guerra, Deanna; Quaglino, Daniela; Ronchetti, Ivonne; Calandra Buonaura, Sebastiano; Bertolini, S.
abstract
Pseudoxanthoma Elasticum (PXE), an autosomal recessive disease due to mutations in ABCC6 gene, is characterised by fragmentation of elastic fibres with involvement of the cardiovascular system. We investigated a 60-year-old female with angina pectoris found to have PXE, associated with elevated plasma LDL-C suspected to be due to autosomal-co-dominant hypercholesterolemia. METHODS: ABCC6, LDLR, PCSK9 and exon 26 of APOB genes were re-sequenced. Cardiovascular involvement was assessed by coronary angiography, single-photon emission computed tomography (SPECT) and ultrasound examination. RESULTS AND CONCLUSIONS: The patient was a compound heterozygous for two ABCC6 mutations (p.S317R and p.R1141X) and heterozygous for a novel LDLR mutation (p.R574H). She had severe coronary stenosis and calcification of the arteries of the lower limbs. Treatment with ezetimibe/simvastatin 10/60mg/day, maintained over a 4.5-year period, reduced of LDL-C and the myocardial ischemic area. In PXE patients LDL-lowering treatment might contribute to delay macrovascular complications.
2009
- A novel homozygous mutation in CETP gene as a cause of CETP deficiency in a Caucasian kindred.
[Articolo su rivista]
Calabresi, L; Nilsson, P; Pinotti, Elisa; Gomaraschi, M; Favari, E; Adorni, Mp; Bernini, F; Sirtori, Cr; CALANDRA BUONAURA, Sebastiano; Franceschini, G; Tarugi, Patrizia Maria
abstract
ObjectiveTo analyze the cholesteryl ester transfer protein (CETP) gene and the plasma HDL phenotype in a Caucasian subject with extremely elevated plasma high density lipoprotein-cholesterol (HDL-C).Methods and resultsThe proband, a 63-year-old male of Swedish ancestry with elevated HDL-C (208 mg/dl) and apoA-I (and 272 mg/dl), was found to be homozygous for a point mutation in exon 2 of CETP gene (c.109 C > T) resulting in a premature termination codon (R37X). Plasma CETP mass and activity were undetectable. Plasma HDL were characterized by predominance of large HDL with enhanced preβ-HDL content. The proband's sons, heterozygotes for the mutation, had reduced plasma CETP activity and moderately elevated HDL-C. Serum of CETP deficient subjects showed a normal or enhanced cholesterol efflux capacity via ABCG1/SR-BI; cholesterol efflux via ABCA1 and macrophage cholesterol removal were lower than normal. The proband was healthy and had no atherosclerotic plaques in carotid or femoral arteries.ConclusionComplete CETP deficiency caused by mutations in CETP gene is exceedingly rare in Caucasians; the description of this single case indicates that CETP deficiency does not predispose to atherosclerosis in the absence of major cardiovascular risk factors.
2009
- Familial hypobetalipoproteinemia: clinical characterization of a new mutation in the APOB gene
[Articolo su rivista]
Iglesias, P; Díez, Jj; Tarugi, Patrizia Maria
abstract
BACKGROUND AND OBJETIVE: Familial hypobetalipoproteinemia (FHB) is usually due to mutations in the APOB gene. Almost 60 different mutations have been reported. We report a Spanish family with FHB phenotype and a new mutation. PATIENT AND METHODS: We performed an analytical, localizing and molecular study of the APOB gene in the proband and in two relatives phenotypically affected. RESULTS: The proband was a 32-year-old woman with moderate to severe mental retardation, morbid obesity, hypocholesterolemia, hypertransaminasemia, and hepatic steatosis. The familial phenotypic study was positive in other 6 relatives. The genetic study confirmed the presence of a novel mutation (apoB-69.27) in the APOB gene. The proband, her mother and one maternal great aunt were heterozygote for that mutation. CONCLUSIONS: FHB has a variable phenotypic expression that can range from oligosymptomatic disease to severe neurological damage.
2009
- Functional analysis of two novel splice site mutations of APOB gene in familial hypobetalipoproteinemia.
[Articolo su rivista]
Di Leo, E; Magnolo, L; Pinotti, Elisa; Martini, S; Cortella, I; Vitturi, N; Rabacchi, Claudio; Wunsch, A; Pucci, F; Bertolini, S; Calandra Buonaura, Sebastiano; Tarugi, Patrizia Maria
abstract
Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by reduced plasma levels of low density lipoprotein cholesterol (LDL-C) and its protein constituent apolipoprotein B (apoB), which may be due to mutations in APOB gene, mostly located in the coding region of this gene. We report two novel APOB gene mutations involving the acceptor splice site of intron 11 (c.1471-1G>A) and of intron 23 (c.3697-1G>C), respectively, which were identified in two patients with heterozygous FHBL associated with severe fatty liver disease. The effects of these mutations on APOB pre-mRNA splicing were assessed in COS-1 cells expressing the mutant APOB minigenes.The c.1471-1G>A APOB minigene generated two abnormal mRNAs. In one mRNA the entire intron 11 was retained; in the other mRNA exon 11 joined to exon 12, in which the first nucleotide was deleted due to the activation of a novel acceptor splice site. The predicted products of these mRNAs are truncated proteins of 546 and 474 amino acids, designated apoB-12.03 and apoB-10.45, respectively. The c.3697-1G>C APOB minigene generated a single abnormal mRNA in which exon 23 joined to exon 25, with the complete skipping of exon 24. This abnormal mRNA is predicted to encode a truncated protein of 1220 amino acids, designated apoB-26.89.These splice site mutations cause the formation of short truncated apoBs, which are not secreted into the plasma as lipoprotein constituents. This secretion defect is the major cause of severe fatty liver observed in carriers of these mutations.
2009
- Identification of patients with abetalipoproteinemia and homozygous familial hypobetalipoproteinemia in Tunisia
[Articolo su rivista]
M., Najah; E., Di Leo; J., Awatef; Magnolo, Antonia Lucia; J., Imene; Pinotti, Elisa; M., Bahri; S., Barsaoui; I., Brini; M., Fekih; M. N., Slimane; Tarugi, Patrizia Maria
abstract
BACKGROUND: Abetalipoproteinemia (ABL) and Homozygous Familial Hypobetalipoproteinemia (Ho-FHBL) are rare monogenic diseases characterised by very low plasma levels of cholesterol and triglyceride and the absence or a great reduction of apolipoprotein B (apoB)-containing lipoproteins. ABL results from mutations in the MTP gene; Ho-FHBL may be due to mutations in the APOB gene. METHODS: We sequenced MTP and APOB genes in three Tunisian children, born from consanguineous marriage, with very low levels of plasma apoB-containing lipoproteins associated with severe intestinal fat malabsorption. RESULTS: Two of them were found to be homozygous for two novel mutations in intron 5 (c.619-3T>G) and in exon 8 (c.923 G>A) of the MTP gene, respectively. The c.619-3T>G substitution caused the formation of an abnormal mRNA devoid of exon 6, predicted to encode a truncated MTP of 233 amino acids. The c.923 G>A is a nonsense mutation resulting in a truncated MTP protein (p.W308X). The third patient was homozygous for a novel nucleotide deletion (c.2172delT) in exon 15 of APOB gene resulting in the formation of a truncated apoB of 706 amino acids (apoB-15.56). CONCLUSIONS: These mutations are expected to abolish the apoB lipidation and the assembly of apoB-containing lipoproteins in both liver and intestine.
2009
- Molecular analysis of NPC1 and NPC2 gene in 34 Niemann-Pick C Italian Patients: Identification and structural modeling of novel mutations
[Articolo su rivista]
Fancello, T; Dardis, A; Rosano, C; Tarugi, Patrizia Maria; Tappino, B; Zampieri, S; Pinotti, Elisa; Corsolini, F; Fecarotta, S; D'Amico, A; DI ROCCO, M; Uziel, G; CALANDRA BUONAURA, Sebastiano; Bembi, B; Filocamo, M.
abstract
Niemann–Pick C, the autosomal recessive neuro-visceral disease resulting from a failure of cholesterol trafficking within the endosomal–lysosomal pathway, is due to mutations in NPC1 or NPC2 genes. We characterized 34 unrelated patients including 32 patients with mutations in NPC1 gene and two patients in NPC2 gene. Overall, 33 distinct genotypes were encountered. Among the 21 unpublished NPC1 alleles, 15 were due to point mutations resulting in 13 codon replacements (p.C100S, p.P237L, p.R389L, p.L472H, p.Y634C, p.S636F, p.V780G, p.Q921P, p.Y1019C, p.R1077Q, p.L1102F, p.A1187V, and p.L1191F) and in two premature stop codons (p.R934X and p.Q447X); a new mutant carried two in cis mutations, p.[L648H;M1142T] and four other NPC1 alleles were small deletions/insertions leading both to frame shifts and premature protein truncations (p.C31WfsX26, p.F284LfsX26, p.E1188fsX54, and p.T1205NfsX53). Finally, the new intronic c.464-2A>C change at the 3′ acceptor splice site of intron 4 affected NPC1 messenger RNA processing. We also found a new NPC2 mutant caused by a change of the first codon (p.M1L). The novel missense mutations were further investigated by two bioinformatics approaches. Panther proein classification system computationally predicted the detrimental effect of all new missense mutations occurring at evolutionary conserved positions. The other bioinformatics approach was based on prediction of structural alterations induced by missense mutations on the NPC1 atomic models. The in silico analysis predicted protein malfunctioning and/or local folding alteration for most missense mutations. Moreover, the effects of the missense mutations (p.Y634C, p.S636F, p.L648H, and p.V780G) affecting the sterol-sensing domain (SSD) were evaluated by docking simulation between the atomic coordinates of SSD model and cholesterol.
2009
- Novel LMF1 nonsense mutation in a patient with severe hypertriglyceridemia
[Articolo su rivista]
Cefalù, Ab; Noto, D; Arpi, Ml; Yin, F; Spina, R; Hilden, H; Barbagallo, Cm; Carroccio, A; Tarugi, Patrizia Maria; Squatrito, S; Vigneri, R; Taskinen, Mr; Péterfy, M; Averna, M. R.
abstract
CONTEXT: Lipase maturation factor 1 (LMF1) gene is a novel candidate gene in severe hypertriglyceridemia. Lmf1 is involved in the maturation of lipoprotein lipase (LPL) and hepatic lipase in endoplasmic reticulum. To date only one patient with severe hypertriglyceridemia and related disorders was found to be homozygous for a nonsense mutation in LMF1 gene (Y439X). OBJECTIVE: The objective of the study was to investigate LMF1 gene in hypertriglyceridemic patients in whom mutations in LPL, APOC2, and APOA5 genes had been excluded. RESULTS: The resequencing of LMF1 gene led to the discovery of a novel homozygous nonsense mutation in one patient with severe hypertriglyceridemia and recurrent episodes of pancreatitis. The mutation causes a G>A substitution in exon 9 (c.1395G>A), leading to a premature stop codon (W464X). LPL activity and mass were reduced by 76 and 50%, respectively, compared with normolipidemic controls. The proband over the years has shown a good response to treatment. The proband's son, heterozygous for the W464X, shows normal plasma triglyceride levels. CONCLUSIONS: We identified the second novel pathogenic mutation in LMF1 gene in a patient with severe hypertriglyceridemia. LPL deficiency in our patient was milder than in the carrier of the Y439X previously described.
2009
- Novel mutations of CETP gene in Italian subjects with hyeralphalipoproteinemia
[Articolo su rivista]
CEFALÙ, AB; NOTO, D; MAGNOLO, Antonia Lucia; PINOTTI, Elisa; GOMARASCHI, M; MARTINI, S; VIGNA, GB; CALABRESI, L; TARUGI, Patrizia Maria; AVERNA, MR
abstract
Cholesteryl ester transfer protein (CETP) is a plasma glycoprotein that catalyses the transfer of cholesteryl esters from HDL to the other plasma lipoproteins. Genetic deficiency of CETP is one of the known causes of elevation of plasma HDL-C (primary hyperalphalipoproteinemia, HALP). We sequenced CETP gene in a group of 24 Italian subjects with primary HALP (HDL-C>80 mg/dl) suspected to have CETP deficiency. Two unrelated subjects both coming from the same geographical district, were found to be heterozygous for a nucleotide substitution in exon 6 (c.544C>T) and another subject was found to be heterozygous for a C>T transition in exon 9 (c.802C>T). Both mutations introduce a premature stop codon and are predicted to cause the production of truncated proteins (Q165X and R268X, respectively) devoid of function. The fourth proband was found to carry a T>C substitution in intron 15 (c.1407+2T>C) predicted to abolish the function of the donor splice site. To define the effect of this mutation on CETP pre-mRNA splicing we analysed CETP mRNA in COS-1 cells expressing a CETP minigene harbouring the mutation. The analysis of minigene transcript in COS-1 cells showed that IVS15+2T>C mutation caused the formation of an abnormal mRNA in which exon 14 joins directly to exon 16, predicted to encode a truncated peptide of 435 amino acids. In mutation carriers plasma CETP activity was found to be reduced by 38-60%. These are the first mutations in the CETP gene found in Italian subjects with HALP.
2009
- PCSK9 dominant negative mutant results in increased LDL catabolic rate and familial hypobetalipoproteinemia
[Articolo su rivista]
Cariou, B; Ouguerram, K; Zaïr, Y; Guerois, R; Langhi, C; Kourimate, S; Benoit, I; Le May, C; Gayet, C; Belabbas, K; Dufernez, F; Chétiveaux, M; Tarugi, Patrizia Maria; Krempf, M; Benlian, P; Costet, P.
abstract
OBJECTIVE: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a central player in the regulation of cholesterol homeostasis, increasing the low-density lipoprotein (LDL) receptor degradation. Our study aimed at exploring the pathogenic consequences in vivo and in vitro of a PCSK9 prodomain mutation found in a family with hypobetalipoproteinemia (FHBL). METHODS AND RESULTS: A white 49-year-old diabetic man had profound FBHL (LDLC: 16 mg/dL) whereas his daughter and sister displayed a milder phenotype (LDLC 44 mg/dL and 57 mg/dL, respectively), all otherwise healthy with a normal liver function. A monoallelic PCSK9 double-mutant R104C/V114A cosegregated with FBHL, with no mutation found at other FHBL-causing loci. A dose-effect was also found in FBHL relatives for plasma APOB and PCSK9 (very-low to undetectable in proband, approximately 50% decreased in sister and daughter) and LDL catabolic rate (256% and 88% increased in proband and daughter). Transient transfection in hepatocytes showed severely impaired processing and secretion of the double mutant which acted as a dominant negative over secretion of wild-type PCSK9. CONCLUSIONS: These results show that heterozygous PCSK9 missense mutations may associate with profound hypobetalipoproteinemia and constitute the first direct evidence in human that decrease of plasma LDLC concentrations associated to PCSK9 LOF mutations are attributable to an increased clearance rate of LDL.
2008
- Genetics and molecular biology: proprotein convertase subtilisin/kexin type 9 and LDL receptor--an intriguing story.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
Genetic studies in humans and mice have demonstrated that proprotein convertase subtilisin/kexin type 9 (PCSK9) protein is involved in the post-translational regulation of LDL-receptor (LDL-R) protein levels in hepatocytes [1,2]. Several lines of evidence indicate that mature PCSK9 is secreted by hepatocytes and interacts with LDL-R on the cell surface. Secreted PCSK9 (or recombinant PCSK9), when added to cultured hepatocytes, readily reduces LDL-R protein levels in a time-dependent and concentration-dependent manner. PCSK9 is endocytosed and exhibits endosomal/lysosomal localization. Endocytosis of PCSK9 is mediated by LDL-R, because it is not observed in LDL-R-deficient hepatocytes or in hepatocytes deficient in autosomal recessive hypercholesterolaemia (ARH) protein [3,4•] – an adaptor protein that is required for LDL-R internalization. When infused into mice, human recombinant PCSK9 was able to reduce hepatic LDL-R protein levels and elevate plasma LDL [3]. Thus, the idea has progressively emerged that, at least in hepatocytes, secreted PCSK9 interacts directly with the extracellular domain of the LDL-R and undergoes LDL-R/ARH-mediated endocytosis, leading to intracellular degradation of the LDL-R [3,4•]. A key question underlying the interaction between PCSK9 and LDL-R concerns the site in the extracellular domain of LDL-R that binds to PCSK9. A recent study [5••] showed that PCSK9 interacts with the first epidermal growth factor repeat (EGF-A) in the EGF-precursor homology domain of LDL-R. This interaction is greatly increased with reduction in pH from 7 to 5.2, suggesting that PCSK9 binds to LDL-R at the cell surface at neutral pH and remains strongly associated with it in the acidic environment of the endosomes, where the binding affinity to LDL-R is increased by more than 100-fold. In endosomes PCSK9 would lock LDL-R in a specific conformation that favours degradation of the receptor instead of its recycling back to the plasma membrane [5••,6•]. This finding raises the question of whether naturally occurring mutations in the EGF-A domain of LDL-R increase or, vice versa, decrease the affinity of the receptor for PCSK9. In the first case, the increased PCSK9-dependent LDL-R degradation would result in hypercholesterolaemia, whereas in the second case the reduced LDL-R degradation would result in hypocholesterolaemia. The site of PCSK9 involved in binding to LDL-R remains to be defined. It is probable that functional and structural studies of PCSK9 mutants will assist with mapping this site [7••,8]. Two other questions have been addressed, namely whether the binding of LDL to LDL-R affects the interaction between PCSK9 and LDL-R, and whether PCSK9 is directly responsible for the proteolytic degradation of LDL-R. According to Fisher et al. [6•], binding of LDL diminishes PCSK9 binding to LDL-R in vitro, and partially inhibits the effect of secreted PCSK9 on LDL-R degradation within the cell. Deletion of the LDL-binding domain of the LDL-R does not affect binding of PCSK9, however, thus indicating that PCSK9 can bind to LDL-R independently of lipoproteins [5••]. With regard to the second question, two studies [9••,10] showed that catalytic activity is not required for secreted PCSK9 to induce LDL-R degradation. Catalytic inactive wild-type or mutant PCSK9 (harbouring the gain-of-function mutation D374Y) exhibited no loss of binding capacity to LDL-R, suggesting that the role played by PCSK9 is that of a molecular chaperone directing LDL-R to lysosomal degradation [9••]. Catalytic activity is, however, required for the intracellular autocatalytic cleavage of the prodomain and the secretion of PCSK9 from the cells. There are, however, gain-of-function mutations that prevent autocatalytic cleavage or secretion of PCSK9, but that nevertheless induce LDL-R degradation, suggesting that PCSK9 may also function intracellularly [11]. The story of PCSK9 continues and is full of surprises.
2008
- Variable phenotypic expression of homozygous familial hypobetalipoproteinaemia due to novel APOB gene mutations
[Articolo su rivista]
E., Di Leo E; Magnolo, Antonia Lucia; Bertolotti, Marco; M., Bourbon; S., Carmo Pereira; M., Pirisi; CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
Homozygous familial hypobetalipoproteinaemia (Ho-FHBL) is a rare co-dominant disorder characterized by extremely low levels of low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (apoB). Most patients with Ho-FHBL have mutations in APOB gene resulting in truncated apoBs. Some patients are asymptomatic, while others have fatty liver, intestinal fat malabsorption and neurological dysfunctions. We investigated three adult subjects with severe hypobetalipoproteinaemia and a family history of FHBL. Proband FHBL-47 had liver cirrhosis with hepatocarcinoma and a renal carcinoma but no clinical manifestations related to FHBL. He was a compound heterozygote for a 7-bp deletion in exon 21 and a base insertion in exon 26 resulting in truncated apoBs (apoB-22.46/apoB-66.51). Proband FHBL-53, with severe hepatic steatosis and fibrosis, had a nonsense mutation in exon 19 resulting in a truncated apoB (apoB-20.61) and a rare nucleotide substitution in intron 14 (c.2068-4T>A). The latter was also present in her daughter, found to have low plasma LDL-C and apoB. Proband FHBL-82 had chronic diarrhoea and steatorrhoea. She was found to be homozygous for a nonsense mutation in exon 24 resulting in a truncated apoB (apoB-26.65). In adult subjects, the presence of chronic liver disease and chronic diarrhoea, when associated with severe hypobetalipoproteinaemia, may lead to the diagnosis of Ho-FHBL.
2007
- A novel loss of function mutation of PCSK9 gene in white subjects with low-plasma low-density lipoprotein cholesterol
[Articolo su rivista]
Fasano, Tommaso; Cefalu, Ab; Di Leo, E; Noto, D; Pollaccia, D; Bocchi, Letizia; Valenti, V; Bonardi, R; Guardamagna, O; Averna, M; Tarugi, Patrizia Maria
abstract
Objectives - The PCSK9 gene, encoding a pro-protein convertase involved in posttranslational degradation of low-density lipoprotein receptor, has emerged as a key regulator of plasma low-density lipoprotein cholesterol. In African-Americans two nonsense mutations resulting in loss of function of PCSK9 are associated with a 30% to 40% reduction of plasma low-density lipoprotein cholesterol. The aim of this study was to assess whether loss of function mutations of PCSK9 were a cause of familial hypobetalipoproteinemia and a determinant of low-plasma low-density lipoprotein cholesterol in whites. Methods and Results - We sequenced PCSK9 gene in 18 familial hypobetalipoproteinemia subjects and in 102 hypocholesterolemic blood donors who were negative for APOB gene mutations known to cause familial hypobetalipoproteinemia. The PCSK9 gene variants found in these 2 groups were screened in 42 subjects in the lowest (< 5(th)) percentile, 44 in the highest (> 95(th)) percentile, and 100 with the average plasma cholesterol derived from general population. In one familial hypobetalipoproteinemia kindred and in 2 hypocholesterolemic blood donors we found a novel PCSK9 mutation in exon 1 (c.202delG) resulting in a truncated peptide (Ala68fsLeu82X). Two familial hypobetalipoproteinemia subjects and 4 hypocholesterolemic blood donors were carriers of the R46L substitution previously reported to be associated with reduced low-density lipoprotein cholesterol as well as other rare amino acid changes (T77I, V114A, A522T and P616L) not found in the other groups examined. Conclusions - We discovered a novel inactivating mutation as well as some rare nonconservative amino acid substitutions of PCSK9 in white hypocholesterolemic individuals.
2007
- Abnormal apolipoprotein B pre-mRNA splicing in patients with familial hypobetalipoproteinaemia
[Articolo su rivista]
Di Leo, E; Magnolo, Antonia Lucia; Lancellotti, Sandra; Crocè, L; Visintin, L; Tiribelli, C; Bertolini, S; CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
Background: Familial hypobetalipoproteinaemia (FHBL) is a codominant disorder characterised by fatty liver and reduced plasma levels of low-density lipoprotein (LDL) and its protein constituent apolipoprotein B ( apoB). FHBL is linked to the APOB gene in some but not all known cases. In a group of 59 patients with FHBL genotyped for APOB gene mutations, we found three novel splice-site mutations: c. 904+4AR -> G in intron 8, c. 3843-2A -> G in intron 24 and c. 4217-1G -> RT in intron 25. Objective: To assess the effects of these mutations on apoB prem-RNA splicing. Methods: ApoB mRNA was analysed in the liver of one proband and in cells expressing APOB minigenes harbouring the mutations found in the other probands. Results: In the liver of the c. 3843-2A -> RG carrier, an apoB mRNA devoid of exon 25 was identified, predicted to encode a truncated peptide of 1260 amino acids. The analysis of minigene transcripts in COS-1 cells showed that the c. 904+4A -> G mutation caused the formation of an mRNA devoid of exon 8, predicted to encode a short apoB of 247 amino acids. The minigene harbouring the c. 4217-1G -> T mutation in intron 25 generated an mRNA in which exon 25 joined to a partially deleted exon 26, resulting from the activation of an acceptor site in exon 26; this mRNA is predicted to encode a truncated protein of 1380 amino acids. All these truncated apoBs were not secreted as constituents of plasma lipoproteins. Conclusion: These findings demonstrate the pathogenic effect of rare splice- site mutations of the APOB gene found in FHBL.
2007
- Genetics of familial hypobetalipoproteinemia
[Articolo su rivista]
Tarugi, P.; Averna, M.
abstract
Primary hypobetalipoproteinemias include three monogenic disorders: the relatively frequent codominant familial hypobetalipoproteinemia (FHBL), the rare recessive conditions abetalipoproteinemia (ABL) and chylomicron retention disease (CMRD). Approximately 50% of FHBL patients are carriers of mutations in the APOB gene, mostly causing the formation of truncated forms of ApoB. In some kindred, FHBL is linked to a locus on chromosome 3 (3p21), but the candidate gene is still unknown: Recently, a FHBL-like phenotype was observed in carriers of mutations of the proprotein convertase subtilisin/kexin type 9 (PCSK9) gene causing loss-of-function of the encoded protein, a proprotein convertase that regulates LDL-receptor number in the liver. Inactivation of the PCSK9 protein is associated with an increased number of LDC receptors and increased receptor-mediated hepatic uptake of plasma LDL. ABL and CMRD are due to mutations in the microsomal triglyceride transfer protein and Sar1-ADP-ribosylation GTPase 2 genes, which affect assembly and secretion of ApoB-containing lipoproteins. In this review we present the current information on the genetics and pathophysiology of these disorders affecting either the secretion or the catabolism of ApoB-containing lipoproteins. © 2007 Future Medicine Ltd.
2007
- Molecular diagnosis of hypobetalipoproteinemia: an ENID Review
[Articolo su rivista]
Tarugi, Patrizia Maria; Averna, M; DI LEO, E; Cefalù, Ab; Noto, D; Magnolo, Antonia Lucia; Cattin, L; Bertolini, S; CALANDRA BUONAURA, Sebastiano
abstract
Primary hypobetalipoproteinemia (HBL) includes a group of genetic disorders: abetalipoproteinemia (ABL) and chylomicron retention disease (CRD), with a recessive transmission, and familial hypobetalipoproteinemia (FHBL) with a co-dominant transmission. ABL and CRD are rare disorders due to mutations in the MTP and SARA2 genes, respectively. Heterozygous FHBL is much more frequent. FHBL subjects often have fatty liver and, less frequently, intestinal fat malabsorption. FHBL may be linked or not to the APOB gene. Most mutations in APOB gene cause the formation of truncated forms of apoB which may or may be not secreted into the plasma. Truncated apoBs with a size below that of apoB-30 are not detectable in plasma; they are more frequent in patients with the most severe phenotype. Only a single amino acid substitution (R463W) has been reported as the cause of FHBL. Approximately 50% of FHBL subjects are carriers of pathogenic mutations in APOB gene; therefore, a large proportion of FHBL subjects have no apoB gene mutations or are carriers of rare amino acid substitutions in apoB with unknown effect. In some kindred FHBL is linked to a locus on chromosome 3 (3p21) but the candidate gene is unknown. Recently a FHBL plasma lipid phenotype was observed in carriers of mutations of the PCSK9 gene causing loss of function of the encoded protein, a proprotein convertase which regulates LDL-receptor number in the liver. Inactivation of this enzyme is associated with an increased LDL uptake and hypobetalipoproteinemia. HBL carriers of PCSK9 mutations do not develop fatty liver disease.
2006
- A novel sequence variant in APOA5 gene found in patients with severe hypertriglyceridemia
[Articolo su rivista]
PRIORE OLIVA, Claudio; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; L., Pisciotta; A., Bellocchio; S., Bertolini; O., Guardamagna; Fg, Schaap
abstract
The APOA5 gene encoding apolipoprotein A-V (a 366amino acid protein), present in minute amounts in VLDL andHDL, appears to be a modulator of plasma triglyceride (TG)homeostasis [1,2]. In apoA5 knock out mice plasma TG levelincreased almost four-fold, whereas in human APO5 transgenicmice it decreased 70% [1]. Some SNPs in the APOA5gene have been associated with differences in plasma TG levelsin the general population [1]. There is robust evidence thatapo A-V accelerates VLDL and chylomicron catabolism byactivating lipoprotein lipase (LPL)-mediated lipolysis [3–7].
2006
- APOA5 and trigliceride metabolism, lesson from human APOA5 deficiency.
[Articolo su rivista]
Calandra Buonaura, Sebastiano; Priore Oliva, Claudio; Tarugi, Patrizia Maria; Bertolini, S.
abstract
Purpose of review: In this review we compare the phenotype and lipoprotein abnormalities of some patients who were found to carry mutations in the APOA5 gene predicted to result in apolipoprotein A-V deficiency. Recent findings: The sequencing of the APOA5 gene in patients with primary hypertriglyceridemia, in whom mutations of the LPL and APOC2 genes had been excluded, led to the identification of four families with two different mutations in this gene predicted to result in truncated apolipoprotein A-V. The first mutation (Q148X) was found in a homozygous state in a child with severe type V hyperlipidemia, some clinical manifestations of chylomicronemia syndrome and a slight reduction in plasma postheparin lipoprotein lipase activity. Carriers of a different mutation (Q139X) were recently reported. Four Q139X heterozygotes had type V hyperlipidemia and markedly reduced plasma postheparin lipoprotein lipase activity. The hypertriglyceridemic Q139X heterozygote had other factors that could have contributed to hypertriglyceridemia. ApoB-100 kinetic studies in hypertriglyceridemic Q139X heterozygotes revealed an impairment of very low-density lipoprotein catabolism. Summary: Mutations in the APOA5 gene, leading to truncated apolipoprotein A-V devoid of lipid-binding domains located in the carboxy-terminal end of the protein, if present in the homozygous state, are expected to cause severe type V hyperlipidemia in patients with no mutations in LPL or APOC2 genes. If present in the heterozygous state, these mutations predispose to hypertriglyceridemia in combination with other genetic factors or pathological conditions.
2006
- Additive effect of mutations in LDLR and PCSK9 genes on the phenotype of familial hypercholesterolemia
[Articolo su rivista]
L., Pisciotta; PRIORE OLIVA, Claudio; Ab, Cefalu; D., Noto; A., Bellocchio; R., Fresa; A., Cantafora; D., Patel; M., Averna; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; S., Bertolini
abstract
Patients homozygous or Compound heterozygous for LDLR mutations or double heterozygous for LDLR and apo B R3500Q mutation have higher LDL-C levels. more extensive xanthomatosis and more severe premature coronary disease (pCAD) than simple heterozygotes for mutations in either these genes or for missense mutations in PCSK9 gene. It is not known whether combined mutations in LDLR and PKCS9 are associated with such a severe phenotype. We sequenced Apo B and PCSK9 genes in two patients with the clinical diagnosis of homozygous FH who were heterozygous for LDLR gene mutations. Proband Z.P. (LDL-C 13.39 mmol/L and pCAD) was heterozygous for an LDLR mutation (p.E228K) inherited from her father (LDL-C 8.07 mmol/L) and a PCSK9 mutation (p.R496W) from her mother (LDL-C 5.58 mmol/L). Proband L.R. and her sister (LDL-C 11.51 and 10.47 mmol/L. xanthomatosis and carotid atherosclerosis) were heterozygous for all LDLR mutation (p.Y419X) inherited from their mother (LDL-C 6.54 mmol/L) and a PCSK9 mutation (p.N425S) probably from their deceased father. The LDL-C levels in double heterozygotes of these two families were 56 and 44% higher than those found in simple heterozygotes for the two LDLR mutations, respectively. The two PCSK9 Mutations are novel and were not found in I 10 controls and 80 patients with co-dominant hypercholesterolemia. These observations indicate that Fare missense Mutations of PCSK9 may worsen the clinical phenotype of patients carrying LDLR mutations.
2005
- Combined monogenic hypercholesterolemia and hypoalphalipoproteinemia caused by mutations in LDL-R and LCAT genes
[Articolo su rivista]
Pisciotta, L; Calabresi, L; Luppattelli, G; Siepi, D; Mannarino, Mr; Moleri, E.; Bellocchio, A; Cantafora, A; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Bertolini, S.
abstract
We studied a three generation family with co-dominant monogenic hypercholesterolemia and hypoalphalipoproteinemia. The proband, a 48 year-old male, was found to be heterozygous for a previously reported mutation in LDL receptor (LDL-R) gene (IVS15–3 c>a) and a novel mutation in exon 6 of lecithin cholesterol acyltransferase (LCAT) gene (c.803 G>A) causing a non-synonymous amino acid substitution (p.R244H). These mutations segregated independently in the family. The LDL-R mutation was associated with high levels of LDL-C (6.20–9.85 mmol/L) and apo B (170–255 mg/dL), comparable to those previously reported in carriers of the same mutation. The LCAT mutation was associated with low levels of HDL-C (0.67–0.80 mmol/L) and apo A-I (96–110 mg/dL). The proband had reduced LCAT function, as measured by cholesterol esterification rate (29 nmol/(mL/h) versus 30–60 nmol/(mL/h)), LCAT activity (10 nmol/(mL/h) versus 20–55 nmol/(mL/h)) and LCAT mass (2.87 μg/mL versus 3.1–6.7 μg/mL). Carriers of LCAT mutation had lower LCAT activity and a tendency to reduced cholestrol esterification rate (CER) and LCAT mass as compared to non-carrier family members. The LCAT mutation was not found in 80 control subjects and 60 patients with primary hypoalphalipoproteinemia. Despite the unfavourable lipoprotein profile, the proband had only mild clinical signs of atherosclerosis. This unexpected finding is probably due to the intensive lipid lowering treatment the patient has been on over the last decade.
2005
- Inherited apolipoprotein A-V deficiency in severe hypertriglyceridemia
[Articolo su rivista]
PRIORE OLIVA, Claudio; L., Pisciotta; G., Li Volti; M. P., Sambataro; A., Cantafora; A., Bellocchio; A., Catapano; Tarugi, Patrizia Maria; S., Bertolini; CALANDRA BUONAURA, Sebastiano
abstract
Objective - Mutations in LPL or APOC2 genes are recognized causes of inherited forms of severe hypertriglyceridemia. However, some hypertrigliceridemic patients do not have mutations in either of these genes. Because inactivation or hyperexpression of APOA5 gene, encoding apolipoprotein A-V (apoA-V), causes a marked increase or decrease of plasma triglycerides in mice, and because some common polymorphisms of this gene affect plasma triglycerides in humans, we have hypothesized that loss of function mutations in APOA5 gene might cause hypertriglyceridemia. Methods and Results - We sequenced APOA5 gene in 10 hypertriglyceridemic patients in whom mutations in LPL and APOC2 genes had been excluded. One of them was found to be homozygous for a mutation in APOA5 gene ( c. 433 C > T, Q145X), predicted to generate a truncated apoA-V devoid of key functional domains. The plasma of this patient was found to activate LPL in vitro less efficiently than control plasma, thus suggesting that apoA-V might be an activator of LPL. Ten carriers of Q145X mutation were found in the patient's family; 5 of them had mild hypertriglyceridemia. Conclusions - As predicted from animal studies, apoA-V deficiency is associated with severe hypertriglyceridemia in humans. This observation suggests that apoA-V regulates the secretion and/or catabolism of triglyceride-rich lipoproteins.
2005
- Lung involvement in Niemann-Pick disease type C1: improvement with bronchoalveolar lavage
[Articolo su rivista]
S., Palmeri; Tarugi, Patrizia Maria; F., Sicurelli; R., Buccoliero; A., Malandrini; MM De, Santi; G., Marciano; C., Battisti; Mt, Dotti; CALANDRA BUONAURA, Sebastiano; A., Federico
abstract
Progressive lung infiltration is a major cause of death in Niemann-Pick disease type A and B (NPA, NPB) and in the recently defined type C2. In type C1 (NPC1), the main manifestations are neurological. We report a patient with a classic, neurological, late infantile form of NPC1 disease, carrying the mutation P474L and the variant 1642M in the NPC1 gene, who suffered recurrent respiratory manifestations. Bronchoalveolar lavage of a lung segment due to deteriorating respiratory condition revealed many foamy macrophages and was followed by an improvement in symptoms. Pneumopathy may therefore be considered a feature of NPC1 disease for which a partial bronchoalveolar lavage could be a useful treatment.
2005
- Mutations in MTP gene in abeta- and hypobeta-lipoproteinemia
[Articolo su rivista]
Di Leo, E; Lancellotti, Sandra; Penacchioni, Jy; Cefalù, Ab; Averna, M; Pisciotta, L; Bertolini, S; CALANDRA BUONAURA, Sebastiano; Gabelli, C; Tarugi, Patrizia Maria
abstract
Familial hypobetalipoproteinemia (FHBL) and abetalipoproteinemia (ABL) are inherited disorders of apolipoprotein B (apo B)-containing lipoproteins that result from mutations in apo B and microsomal triglyceride transfer protein (MTP) genes, respectively. Here we report three patients with severe deficiency of plasma low-density lipoprotein (LDL) and apo B. Two of them (probands F.A. and P.E.) had clinical and biochemical phenotype consistent with ABL. Proband F.A. was homozygous for a minute deletion/insertion (c.1228delCCCinsT) in exon 9 of MTP gene predicted to cause a truncated MTP protein of 412 amino acids. Proband P. E. was heterozygous for a mutation in intron 9 (IVS9-1G>A), previously reported in an ABL patient. We failed to find the second pathogenic mutation in MTP gene of this patient. No mutations were found in apo B gene.The third proband (D.F.) had a less severe lipoprotein phenotype which was similar to that of heterozygous FHBL and appeared to be inherited as a co-dominant trait. However, he had no mutations in apo B gene. He was found to be a compound heterozygote for two missense mutations (D384A and G661A), involving highly conserved regions of MTP. Since this proband was also homozygous for 2 allele of apolipoprotein E (apo E), it is likely that his hypobetalipoproteinemia derives from a combined effect of a mild MTP deficiency and homozygosity for apo E2 isoform.
2005
- Pediatric gallstone disease in familial hypobetalipoproteinemia
[Articolo su rivista]
Lancellotti, Sandra; M., Zaffanello; E., Di Leo; L., Costa; A., Lonardo; Tarugi, Patrizia Maria
abstract
Familial hypobetalipoproteinemia (FHBL) is an monogenic co-dominant disorder characterized by reduced plasma levels of cholesterol, low density lipoproteins (LDL) and apolipoprotein B (apoB) often associated with non-alcoholic fatty liver disease (NAFLD). It has been suggested that FHBL might predispose to gallstone disease (GD). We report a hypocholesterolemic 10 year old girl with obstructive jaundice due to cholesterol stones in gallbladder and common bile duct which required cholecistectomy. The analysis of patient's plasma lipoproteins revealed a marked reduction of LDL and apoB, a lipid profile consistent with the clinical diagnosis of heterozygous FHBL. The same profile was found in her mother who had severe NAFLD. The analysis of apoB gene, the main candidate gene in FHBL, revealed that the patient and her mother were heterozygotes for a novel nonsense mutation (Y122OX) predicted to cause the formation of a short truncated apoB (apoB-26.87) not secreted into the plasma. The presence of cholesterol stones could result from increased biliary cholesterol secretion as a compensatory mechanism for the reduced capacity of the liver to export cholesterol incorporated into apoB-containing lipoproteins. FHBL should be considered as a possible predisposing factor for cholesterol gallstones in children (190).
2004
- A point mutation in the lariat branch point of intron 6 of NPC1 as the cause of abnormal pre-mRNA splicing in Niemann-Pick type C disease.
[Articolo su rivista]
Di Leo, E; Panico, Francesca; Tarugi, Patrizia Maria; Battisti, C; Federico, A; CALANDRA BUONAURA, Sebastiano
abstract
The lariat branch point sequence (BPS) is crucial for splicing pre-mRNA even if BPS mutations have infrequently been reported in human disease. In two siblings with Niemann-Pick type C (NPC) disease we identified two mutations of the NPC1 gene: i) one in exon 20 (c.2932C>T) (p.R978C) previously reported in NPC patients; ii) the other (c.882-28A>G) unreported, in the highly conserved adenosine of a putative lariat BPS of intron 6. Using RT-PCR we found that, besides the normally spliced mRNA, patients' fibroblasts contained minute amounts of an mRNA devoid of exon 7. The exon 6--exon 8 junction in this mRNA causes a frameshift and a premature stop codon, predicted to result in a truncated protein. To assess the effect of c.882-28A>G mutation we constructed two minigenes (wild type and mutant), spanning from intron 5 to intron 8, which were inserted into a pTarget vector and transfected in COS1 cells. The wild type minigene generated an mRNA of the expected size and sequence; the mutant minigene generated only an mRNA devoid of exon 7. This is the first example of a splicing defect due to a mutation in the lariat BPS in an intron of NPC1 found in NPC patients.
2004
- ABCC6 mutations in Italian families affected by pseudoxanthoma elasticum(PXE).
[Articolo su rivista]
Gheduzzi, Dealba; Guidetti, Rita; Anzivino, Claudia; Tarugi, Patrizia Maria; DI LEO, E; Quaglino, Daniela; Ronchetti, Ivonne
abstract
Pseudoxanthoma elasticum (PXE) is a genetic disorder, characterized by cutaneous, ocular and cardiovascular clinical symptoms, caused by mutations in a gene (ABCC6) that encodes for MRP6 (Multidrug Resistance associated Protein 6), an ATP-binding cassette membrane transporter. The ABCC6 gene was sequenced in 38 unrelated PXE Italian families. The mutation detection rate was 82.9%. Mutant alleles occurred in homozygous, compound heterozygous and heterozygous forms, however the great majority of patients were compound heterozygotes. Twenty-three different mutations were identified, among which 11 were new. Fourteen were missense (61%); five were nonsense (22%); two were frameshift (8.5%) and two were putative splice site mutations (8.5%). The great majority of mutations were located from exon 24 to 30, exon 24 being the most affected. Among the others, exons 9 and 12 were particularly involved. Almost all mutations were located in the intracellular site of MRP6. A positive correlation was observed between patient's age and severity of the disorder, especially for eye alterations. The relevant heterogeneity in clinical manifestations between patients with identical ABCC6 mutations, even within the same family, seems to indicate that, apart from PXE causative mutations, other genes and/or metabolic pathways might influence the clinical expression of the disorder
2004
- Familial HDL deficiency due to ABCA1 gene mutations with or without other genetic lipoprotein disorders
[Articolo su rivista]
L., Pisciotta; I., Hamilton Craig; Tarugi, Patrizia Maria; A., Bellocchio; Fasano, Tommaso; P., Alessandrini; Gb, Bon; D., Siepi; E., Mannarino; L., Cattin; M., Averna; Ab, Cefalu; A., Cantafora; CALANDRA BUONAURA, Sebastiano; S., Bertolini
abstract
Mutations in ABCA1 have been shown to be the cause of Tangier disease (TD) and some forms of familial hypoalphalipoproteinemia (HA), two genetic disorders characterized by low plasma HDL levels. Here we report six subjects with low HDL, carrying seven ABCA1 mutations, six of which are previously unreported. Two mutations (R557X and H160FsX173) were predicted to generate short truncated proteins; two mutations (E284K and Y482C) were located in the first extracellular loop and two (R1901S and Q2196H) in the C-terminal cytoplasmic domain of ABCA1. Two subjects found to be compound heterozygotes for ABCA1 mutations did not have overt clinical manifestations of TD. Three subjects, all with premature coronary artery disease (pCAD), had a combination of genetic defects. Besides being heterozygotes for ABCA1 mutations, two of them were also carriers of the R3500Q substitution in apolipoprotein B and the third was a carrier of N291S substitution in lipoprotein lipase. By extending family studies we identified 17 heterozygotes for ABCA1 mutations. Plasma HDL-C and Apo A-I values in these subjects were 38.3 and 36.9% lower than in unaffected family members and similar to the values found in heterozygotes for Apo A-I gene mutations which prevent Apo A-I synthesis. This survey underlines the allelic heterogeneity of ABCA1 mutations and suggests that: (i) TD subjects, if asymptomatic, may be overlooked and (ii) there may be a selection bias in genotyping towards carriers of ABCA1 mutations who have pCAD possibly related to a combination of genetic and environmental cardiovascular risk factors.
2004
- Familial Hypobetalipoproteinemia Due to a Novel Mutation of Apolipoprotein B Gene " - Horm Res 2004;
[Abstract in Rivista]
Iughetti, Lorenzo; Tarugi, Patrizia Maria; A., Tozzola; Predieri, Barbara; S., Lancellotti; F., Balli; S. B., Calandra
abstract
Since in most of the introns of the human gene A is present in this position it is likely that the presence of a G in this position, like in our patient, disrupts the splicing process.This hypothesis is supported by the observation that proband’s sister who has also hypobetalipoproteinemia was carrier of the same mutation in intron 8. This mutation has not yet been found in normal subjects and in more than 30 FHBL individuals investigated by our group.In FHBL the variability in symptoms was related to the length of the truncated apoB and its ability to form chylomicrons and absorb fat-soluble vitamins and essential fatty acids rather than the levels of LDL-C). Our patient belongs to our series of “symptomatic” heterozygous FHBL subjects with no truncated apoBs detectable in plasma. This finding raises the question as to whether, in a specific FHBL patient/pedegree, hypobetalipoproteinemia is due to mutation in the APOB gene or in other genes (yet to be identified) affecting apoB metabolism. Probably, hypobetalipoproteinemia explains the presence of liver steatosis already at this age, even if it cannot be excluded that obesity should play a role in this alteration.
2004
- Hypobetalipoproteinemia with an apparently recessive inheritance due to a de novo mutation of apolipoprotein B
[Articolo su rivista]
Lancellotti, S; Di Leo, E; Penacchioni, Jy; Balli, Fiorella; Viola, L; Bertolini, S; CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder either linked or not linked to apolipoprotein (apo) B gene. Abetalipoproteinemia (ABL) is a recessive disorder due to mutations of microsomal triglyceride transfer protein (MTP) gene. We investigated a patient with apparently recessive hypobetalipoproteinemia consistent with symptomatic heterozygous FHBL or a mild form of ABL. The proband had fatty liver associated with LDL-cholesterol (LDL-C) and apo B levels <5th percentile but no truncated apo B forms detectable in plasma. MTP gene sequence revealed that he was a carrier of the I128T polymorphism and an unreported amino acid substitution (V168I) unlikely to be the cause of hypobetalipoproteinemia. Apo B gene sequence showed that he was heterozygous for two single base substitutions in exon 9 and 22 resulting in a nonsense (Q294X) and a missense (R1101H) mutation, respectively. Neither of his parents carried the Q294X; his father and paternal grandmother carried the R 110 1 H mutation. Analysis of polymorphic genetic markers excluded non-paternity. In conclusion, the proband has a de novo mutation of apo B gene resulting in a short truncated apo B form (apo B-6.46). Sporadic cases of FHBL with an apparently recessive transmission may be caused by de novo mutations of apo B gene.
2004
- Low-density lipoprotein (LDL) receptor/transferrin fusion protein: in vivoproduction and functional evaluation as a potential therapeutic tool forlowering plasma LDL cholesterol.
[Articolo su rivista]
Razzini, Giorgia; Parise, Flavia; Calebiro, D; Battini, Renata; Bagni, Bruno; Corazzari, Tolmino; Tarugi, Patrizia Maria; Angelelli, Cecilia; Molinari, Susanna; Falqui, L; Ferrari, Stefano
abstract
A soluble form of human low-density lipoprotein receptor (LDL-R) fused in frame with rabbit transferrin (LDL-Rs(hu)/Tf(rab)) is assessed in vivo as a therapeutic tool for lowering plasma LDL cholesterol. The cDNA encoding LDL-Rs(hu)/Tf(rab) is expressed in mice, using a hydrodynamics-based gene transfer procedure. The transgene is transcribed in the liver of transduced animals and the corresponding protein is secreted into the bloodstream. Circulating LDL-Rs(hu)/Tf(rab) binds LDL specifically, thus indicating that it is correctly processed through the cellular compartments in vivo. More importantly, the expression of LDL-Rs(hu)/Tf(rab) allows the removal of injected human (125)I-labeled LDL ((123)I-LDL) from the bloodstream of transduced CD1 mice, which show faster LDL plasma clearance, anticipating by approximately 90 min the same clearance value observed in control animals. A similar effect is observed in transduced LDL-R(-/-) mice, in which the clearance of injected human LDL depends solely on the presence of circulating LDL-Rs(hu) /Tf(rab). In these animals the extent of plasma LDL clearance is directly related to the concentration of LDL-Rs(hu)/Tf(rab) in the blood. Finally, LDL-Rs(hu)/Tf(rab) does not alter the pattern of LDL organ distribution: in transduced animals, as well as in control animals, liver and bladder are the predominantly labeled organs after (123)I-LDL injection. However, LDL-Rs(hu)/Tf(rab) has a quantitative effect on LDL tissue deposition: in treated animals LDL-Rs(hu)/Tf(rab) determines an increase in radioactivity in the liver at early times after (123)I-LDL injection and a progressive labeling of the bladder, starting 20 min after injection.
2004
- The wide spectrum of steatohepatitis: a report of four cases and a review of the literature
[Articolo su rivista]
A., Lonardo; A., Bagni; Tarugi, Patrizia Maria; Loria, Paola
abstract
We report on four cases displaying the wide range of aetiological risk factors (presence or absence of family history of dysilpidaemia and cryptogenic cirrhosis, from subnormal body mass index through morbid obesity, from absent through hepatotoxic alcohol consumption), laboratory test results (from subnormal through elevated uric acid and ferritin values), ultrasonographic changes (from normal findings through 'bright liver' with or without attenuation of ultrasound beam and absence/presence of focal lesions), and histological severity of steatohepatitis (fibrosis appearing to be inversely related to the amount of liver fat but zone 3 accentuation of lesions and ballooning being observed in all cases). Cases illustrate the concepts of overlapping aetiologies of steatohepatitis (hepatitis C, diabetes and lipodystrophy); the relationships between cryptogenic cirrhosis, familial cirrhosis, non-alcoholic fatty liver disease and hepatocellular carcinoma; familial hypobetalipoproteinaemia as an aetiology of steatohepatitis; and alcoholic liver disease in the obese. These issues, which are worthy of future investigation, are reviewed.
2004
- β-thalassemia is a modifying factor of the clinical expression of familial hypercholesterolemia
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; S., Bertolini; Gm, Pes; L., Deiana; Tarugi, Patrizia Maria; L., Pisciotta; S., LI VOLTI; G., LI VOLTI; C., Maccarone
abstract
Familial hypercholesterolemia (FH) is a codominant disorder due to a variety of mutations of the low-density lipoprotein (LDL) receptor gene that result in an elevation of plasma LDL-cholesterol (LDL-C). Plasma levels of LDL-C show large interindividual variation even in subjects carrying the same mutation of the LDL receptor gene. This variability may be due to genetic factors (modifier genes). Several surveys indicate that the overall contribution of common polymorphisms of modifier genes (such as the genes encoding apolipoproteins E and B) to this variability is less than 10%. In contrast, beta-thalassemia has a profound LDL-lowering effect. This was documented in FH patients identified on the island of Sardinia, in Italy, where 12% of the inhabitants are carriers of beta-thalassemia due to a single mutation (Q39X) of the beta-globin gene that abolishes the synthesis of beta-globin chain of hemoglobin (beta(o)-thalassemia). Plasma LDL-C in FH heterozygotes carrying the beta(o)-thalassemia trait is 25% lower than in noncarriers, regardless of the LDL receptor gene mutation. It is likely that this effect is due to two main mechanisms: (1) increased uptake of LDL by the bone marrow to provide cholesterol for the increased proliferation of erythroid progenitor cells and (2) increased production of inflammatory cytokines that reduce the hepatic secretion and increase the catabolism of LDL. In view of its LDL-C-lowering effect, beta-thalassemia trait may protect FH heterozygotes against premature coronary atherosclerosis.
2003
- Abnormal splicing of ABCA1 pre-mRNA in Tangier disease due to a IVS2+5G > C mutation in ABCA1 gene
[Articolo su rivista]
S., Altilia; L., Pisciotta; R., Garuti; Tarugi, Patrizia Maria; A., Cantafora; L., Calabresi; J., Tagliabue; S., Maccari; F., Bernini; I., Zanotti; C., Vergani; S., Bertolini; CALANDRA BUONAURA, Sebastiano
abstract
Two point mutations of ABCA1 gene were found in a patient with Tangier disease (TD): i) G>C in intron 2 (IVS2 +5G>C) and ii) c.844 C>T in exon 9 (R282X). The IVS2 +5G>C mutation was also found in the brother of another deceased TD patient, but not in 78 controls and 33 subjects with low HDL. The IVS2 +5G>C mutation disrupts ABCA1 pre-mRNA splicing in fibroblasts, leading to three abnormal mRNAs: devoid of exon 2 (Ex2(-)/mRNA), exon 4 (Ex4(-)/mRNA), or both these exons (Ex2(-)/Ex4(-)/ mRNA), each containing a translation initiation site. These mRNAs are expected either not to be translated or generate short peptides. To investigate the in vitro effect of IVS2 +5G>C mutation, we constructed two ABCA1 minigenes encompassing Ex1-Ex3 region, one with wild-type (WTgene) and the other with mutant (MTgene) intron 2. These minigenes were transfected into COS1 and NIH3T3, two cell lines with a different ABCA1 gene expression. In COS1 cells, WTgene pre-mRNA was spliced correctly, while the splicing of MTgene pre-mRNA resulted in Ex2-/mRNA. In NIH3T3, no splicing of MTgene pre-mRNA was observed, whereas WTgene pre-mRNA was spliced correctly. These results stress the complexity of ABCA1 pre-mRNA splicing in the presence of splice site mutations.
2003
- Adult-onset Niemann-Pick type C disease: A clinical, neuroimaging, and molecular genetic study
[Articolo su rivista]
C., Battisti; Tarugi, Patrizia Maria; Mt, Dotti; N., De Stefano; A., Vattimo; F., Chierichetti; CALANDRA BUONAURA, Sebastiano; A., Federico
abstract
We report on a patient with adult-onset Niemann-Pick type C (NPC) disease, carrying the mutations P1007 and I1061T in the NPC1 gene, presenting with marked psychiatric changes followed by dystonia and cognitive impairment. Filipin staining, single photon emission computed tomography perfusional, positron emission tomography metabolic, conventional magnetic resonance imaging, and magnetic resonance spectroscopy findings suggested a pathophysiological correlation with phenotype expression. This case expands the clinical and genetic spectrum of the rare adult-onset NPC disease phenotype
2003
- Recurrent mutations of the apolipoprotein A-I gene in three kindreds with severe HDL deficiency
[Articolo su rivista]
L., Pisciotta; R., Miccoli; A., Cantafora; L., Calabresi; Tarugi, Patrizia Maria; P., Alessandrini; G., Bittolo Bon; G., Franceschini; C., Cortese; CALANDRA BUONAURA, Sebastiano; S., Bertolini
abstract
Two siblings with high density lipoprotein (HDL) deficiency and no plasma apolipoprotein A-I (Apo A-I) were found to be homozygous for a cytosine deletion in exon 3 of Apo A-I gene (c.85 del C, Q5FsX11). This mutation causes a frameshift leading to a premature stop codon and abolishes the synthesis of Apo A-I. Although both siblings had corneal opacifications and planar xanthomas, only one of them had premature coronary artery disease, probably as the result of mildly elevated LDL levels. In two other unrelated subjects HDL deficiency was due to heterozygosity for a nucleotide substitution in exon 4 of Apo A-I gene (c.494 T > G, L141R). Both Apo A-I mutations were reported previously in an Italian kindred which included compound heterozygotes and simple heterozygotes. We investigated all carriers of these mutations in the three kindreds and in the one previously reported. Plasma Apo A-I and HDL-C levels were lower in the mutation carriers than in non-carrier family members. These levels, however, were lower in L141R carriers than in carriers of c.85 del C. Haplotype analysis performed using several polymorphisms suggested that both the c.85 del C and L141R are likely to be recurrent mutations. (C) 2003 Elsevier Science Ireland Ltd. All rights reserved.
2002
- European Lipoprotein Club: Report of the 24th ELC Annual Conference, Tutzing, 10-13 September 2001
[Relazione in Atti di Convegno]
Dallinga-Thie, G.; Bowyer, D.; Dallinga-Thie, G.; Dieplinger, H.; Funke, H.; Hofker, M.; Jauhiainen, M.; Nimpf, J.; Staels, B.; Talmud, P.; Tarugi, P.
abstract
2002
- Niemann Pick type C disease: mutations of NPC1 gene and evidence of abnormal expression of some mutant alleles in fibroblasts
[Articolo su rivista]
Tarugi, Patrizia Maria; Ballarini, ; G. Bembi, B.; Battisti, C.; Palmeri, ; S. Panzani, F.; Di Leo, E.; Martini, C.; Federico, A.; CALANDRA BUONAURA, Sebastiano
abstract
We analyzed Niemann-Pick type C disease 1 (NPC1) gene in 12 patients with Niemann-Pick type C disease by sequencing both cDNA obtained from fibroblasts and genomic DNA. All the patients were compound heterozygotes. We found 15 mutations, eight of which previously unreported. The comparison of cDNA and genomic DNA revealed discrepancies in some subjects. In two unrelated patients carrying the same mutations (P474L and nt 2972del2) only one mutant allele (P474L), was expressed in fibroblasts. The mRNA corresponding to the other allele was not detected even in cells incubated with cycloheximide. The promoter variants (-1026T/G and -1186T/C or -238 C/G), found to be in linkage with 2972del2 allele do not explain the lack of expression of this allele, as they were also found in control subjects. In another patient, (N1156S/Q922X) the N1156S allele was expressed in fibroblasts while the expression of the other allele was hardly detectable. In a fourth patient cDNA analysis revealed a point mutation in exon 20 (P1007A) and a 56 nt deletion in exon 22 leading to a frameshift and a premature stop codon. The first mutation was confirmed in genomic DNA; the second turned out to be a T-->G transversion in exon 22, predicted to cause a missense mutation (V1141G). In fact, this transversion generates a donor splice site in exon 22, which causes an abnormal pre-mRNA splicing leading to a partial deletion of this exon. In some NPC patients, therefore, the comparison between cDNA and genomic DNA may reveal an unexpected expression of some mutant alleles of NPC1 gene.
2002
- The C-terminal domain of apolipoprotein A-I is involved in ABCA1-driven phospholipid and cholesterol efflux
[Articolo su rivista]
E., Favari; F., Bernini; Tarugi, Patrizia Maria; G., Franceschini; L., Calabresi
abstract
ABCA1, a member of the ATP-binding cassette family, mediates the efflux of cellular lipids to free apolipoproteins, mainly apoA-I. The role of the C-terminal domain of apoA-I in this process has been evaluated by measuring the efflux capacity of a truncated form (apoA-I-(1-192)) versus intact apoA-I in different cellular models. In stimulated J774 macrophages, cholesterol efflux to apoA-I-(1-192) was remarkably lower than that to the intact apoA-I. The truncated apoA-I, lacking an important lipid-binding domain, was also significantly less efficient in removing phospholipids from stimulated macrophages. No difference was detected with stimulated Tangier fibroblasts that do not express functional ABCA1 The C-terminal domain of apoA-I is clearly involved in ABCA1-driven lipid efflux. Independent of the interaction with the cell surface, it may be the decreased ability of the truncated apoA-I to recruit membrane phospholipids that impairs its capacity to promote cell cholesterol efflux. (C) 2002 Elsevier Science (USA). All rights reserved.
2001
- Phenotypic expression of heterozygous familial hypobetalipoproteinemia in three kindreds with novel mutations of apolipoprotein B gene
[Articolo su rivista]
Tarugi, Patrizia Maria; Lonardo, A.; Gabelli, C.; Sala, F.; Ballarini, G.; Cortella, I.; Previato, L.; Bertolini, S.; Cordera, R.; CALANDRA BUONAURA, Sebastiano
abstract
We report the clinical phenotype in three kindreds with familial heterozygous hypobetalipoproteinemia (FHBL) carrying novel truncated apolipoprotein Bs (apoBs) of different sizes (apoB-8.15, apoB-33.4 and apoB-75.7). In D.A. kindred, we found three carriers of a C-deletion in exon 10 leading to the synthesis of apoB-8.15 not detectable in plasma. They showed steatorrhea and fatty liver. In N.L. kindred, the proband is heterozygous for a nonsense mutation in exon 26, leading to the formation of apoB-33.4. He had premature cerebrovascular disease and fatty liver; two apoB-33.4 carriers in this kindred showed only fatty liver. In B.E. kindred, the proband is heterozygous for a T-deletion in exon 26, which converts tyrosine at codon 3435 into a stop codon, resulting in apoB-75.7. The proband, a heavy alcohol drinker, had steatohepatitis, whereas his teetotaller daughter, an apoB-75.7 carrier, had no detectable fatty liver. This study suggests that: i) fatty liver invariably develops in FHBL carriers of short and medium-size truncated apoBs (< apoB-48), but its occurrence needs additional environmental factors in carriers of longer apoB forms; ii) intestinal lipid malabsorption develops only in carriers of short truncated apoBs, which are not secreted into the plasma; and iii) cerebrovascular disease due to premature atherosclerosis may occur even in FHBL subjects.
2000
- A study of fatty liver disease and plasma lipoproteins in a kindred with familial hypobetalipoproteinemia due to a novel truncated form of apolipoprotein B (apo B-54.5)
[Articolo su rivista]
Tarugi, Patrizia Maria; Lonardo, A.; Ballarini, G.; Erspamer, L.; Tondelli, E.; Bertolini, S.; CALANDRA BUONAURA, Sebastiano
abstract
BACKGROUND/AIMS: Familial hypobetalipoproteinemia (FHBL) is a co-dominant disorder characterized by reduced plasma levels of low-density lipoproteins. It can be caused by mutations in the gene encoding apolipoprotein B-100 (apo B), leading to the formation of truncated apo Bs which have a reduced capacity to export lipids from the hepatocytes as lipoprotein constituents. Case reports suggest the occurrence of liver disease in FHBL, but there are no studies of liver involvement in FHBL with defined apo B gene mutations. The presence of fatty liver disease was investigated in a large FHBL kindred. METHODS: Plasma lipoprotein and apolipoprotein analysis, liver function tests, and apo B gene sequence were performed in 16 members of a FHBL kindred. The presence of fatty liver was assessed by ultrasound and computed tomography scanning. RESULTS: The proband, a non-obese heavy drinker male with hypobetalipoproteinemia, had steatohepatitis with fibrosis. He was heterozygous for a novel non-sense mutation of apo B gene producing a truncated apo B of 2745 amino acids (designated apo B-54.5, having half the size of normal apo B-100). Seven other members of his kindred carried apo B-54.5. Although all of them were hypolipidemic, their lipid levels showed a large inter-individual variability not accounted for by polymorphisms of genes involved in apo B metabolism. Four carriers (two heavy drinkers and two teetotallers), irrespective of their plasma lipid levels, had ultrasonographic evidence of fatty liver. In the other four carriers no evidence of fatty liver was found. CONCLUSIONS: In this kindred apo B-54.5 predisposes to fatty liver, which however may require some additional factors to become clinically relevant.
2000
- European Lipoprotein Club: Report of the 22nd Annual Conference, Tutzing, September 13-16, 1999
[Relazione in Atti di Convegno]
Benlian, P.; Bowyer, D.; Dallinga-Thie, G.; Dieplinger, H.; Funke, H.; Hofker, M.; James, R.; Nimpf, J.; Olivecrona, G.; Talmud, P.; Tarugi, P.; Vilaro, S.
abstract
1999
- Influence of chondroitin sulfate charge density, sulfate group position, and molecular mass on Cu2+-mediated oxidation of human low-density lipoproteins: Effect of normal human plasma-derived chondroitin sulfate
[Articolo su rivista]
Volpi, Nicola; Tarugi, Patrizia Maria
abstract
The effects of chondroitin sulfate samples with decreasing charge densities, different 4-sulfate/6-sulfate ratios, and various molecular masses on Cu2+-induced oxidation of human low-density lipoprotein (LDL) were evaluated by monitoring conjugated diene formation and the tryptophan fluorescence kinetics. Low-sulfated chondroitin sulfate (CS) from beef trachea had a very strong protective antioxidant effect. Quite similar behavior was observed for CS from pig trachea, and a fructose-containing polysaccharide with a chondroitin backbone from Escherichia coli was also strongly protective as to LDL oxidation, CS samples with decreasing charge densities proved effective in inhibiting LDL oxidation, A totally desulfated sample still exhibited a great capacity to protect LDL against oxidation, CS-4-sulfate samples (sulfate to carboxyl ratio of 0.62, about 65% 4-sulfate groups and 5% g-sulfate groups) retained great ability to inhibit the Cu2+-mediated human LDL oxidation, CS fractions with different molecular masses were examined as possible inhibitors of LDL oxidation, Samples with molecular masses lower than about 8,570 (13-15 disaccharide units) were unable to protect human LDL from Cu2+-induced oxidation, Similar results were obtained on studying the degradation of tryptophan residues of the LDL protein moiety resulting from Cu2+ complexation through amino acid residues. A low-sulfated CS (sulfate to carboxyl ratio of 0.41, a molecular mass of about 15,600) having effective anti-oxidant properties as to metal-induced LDL oxidation was isolated from normal human plasma. The protective capacity as to Cu2+-mediated LDL oxidation of CS is discussed in relation to its structure, also considering the physiological role of plasma CS in relation to factors that can alter its properties.
1999
- The protective effect on Cu2+- and AAPH-mediated oxidation of human low-density lipoproteins depends on glycosaminoglycan structure
[Articolo su rivista]
Volpi, Nicola; Tarugi, Patrizia Maria
abstract
The effect of various glycosaminoglycans on Cu2+- and AAPH-induced oxidation of human low-density lipoprotein (LDL) was studied by monitoring conjugated diene formation. Heparin (Hep) increased the lag phase (t(lag)) of LDL oxidation, and fast moving and slow moving Hep species modified the kinetics of LDL oxidation to the same extent. Beef spleen heparan sulfate (HS) sample produced a significant increase of the t(lag) and a decrease of the conjugated diene formation of LDL whilst beef kidney HS species modified LDL oxidation kinetics to a lower extent. Dermatan sulfate (DS) from different sources caused a significant increase of the t(lag) and a decrease of the conjugated diene formation of LDL. Hyaluronic acid had no effect. Chondroitin sulfate (CS) from beef trachea produced a very strong protective antioxidant effect evaluated by increasing of the t(lag) and decreasing of the conjugated diene formation. Hep was completely ineffective in protecting LDL from 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH)-mediated oxidation, whilst DS was moderately effective. Beef trachea CS showed a very strong ability to protect LDL oxidation induced by 1 mM AAPH. The different protective effect on Cu2+- and AAPH-induced LDL oxidation by glycosaminoglycans is discussed considering their various structures and properties, and their capacity to interact to different extents with hydrophobic regions of LDL protein is confirmed by measuring the LDL-tryptophan fluorescence kinetics. (C) 1999 Societe francaise de biochimie et biologie moleculaire / Editions scientifiques et medicales Elsevier SAS.
1998
- Familial heterozygous hypobetalipoproteinemia, extrahepatic primary malignancy, and hepatocellular carcinoma
[Articolo su rivista]
A., Lonardo; Tarugi, Patrizia Maria; G., Ballarini; A., Bagni
abstract
Review. No abstract available.
1998
- Improvement in the high-performance liquid chromatography malondialdehyde level determination in normal human plasma
[Articolo su rivista]
Volpi, Nicola; Tarugi, Patrizia Maria
abstract
We report a very rapid and simple isocratic reversed-phase HPLC separation of malondialdehyde (MDA) in normal human plasma without previous purification of the MDA-2-thiobarbituric acid (TBA) complex. The separation of MDA-TBA complex was performed using a 250 X 4.6 mm Nucleosil-5C18 column with a mobile phase composed of 35% methanol and 65% 50 mM sodium phosphate buffer, pH 7.0. Samples of 50 mu l (composed of 100 mu l plasma mixed with 1.0 ml of 0.2% 2-thiobarbituric acid in 2 M sodium acetate buffer containing 1 mM diethylenetriaminepentaacetic acid, pH 3.5, and 10 mu l of 5% 2,6-di-tert.-butyl-4-methylphenol in 96% ethanol, incubated at 95 degrees C for 45 min [K. Fukunaga, K. Takama and T. Suzuki, Anal. Biochem., 230 (1995) 20] were injected into the column. The MDA-TBA complex was eluted at a flow-rate of 1 ml/min and monitored by fluorescence detection with excitation at 515 nm and emission at 553 nm. Analysis of groups of normal male and female volunteers gave plasma levels of MDA of 1.076 nmol/ml with a coefficient of variation of about 58%. No significant statistical differences were found between male and female groups, and no correlation was discovered on the age. (C) 1998 Elsevier Science B.V. All rights reserved.
1998
- Secretion of apoB- and apoA-I-containing lipoproteins by chick kidney
[Articolo su rivista]
Tarugi, Patrizia Maria; G., Ballarini; B., Pinotti; Franchini, Antonella; Ottaviani, Enzo; CALANDRA BUONAURA, Sebastiano
abstract
Previous studies showed that chick kidney is a site of synthesis of apolipoprotein (ape) B(B-100) and A-I. Aims of the present study were: a) to compare apoB and apoA-I production in chick kidney and liver; b) to investigate whether kidney apolipoproteins were secreted as constituents of lipoproteins; and c) to define the cellular sites of renal apolipoprotein synthesis. Kidney and liver slices taken from the same animals were incubated with S-35-labeled amino acids and radioactive apoB and apoA-I were immunoprecipitated from cell homogenate and incubation medium. The percentage of total protein radioactivity incorporated into cell plus medium apoB and apoA-I was 0.23 +/- 0.08 and 0.19 +/- 0.11 in kidney and 0.38 +/- 0.05 and 0.38 +/- 0.07 in liver, respectively (P < 0.05 kidney vs. liver). S-35-labeled medium lipoproteins were separated by density gradient ultracentrifugation and three major classes corresponding to VLDL + IDL, LDL, and HDL were identified. Most of the apoB secreted by the liver was found in VLDL, IDL, and LDL whereas kidney apoB was found in VLDL, LDL and light HDL (d 1.070-1.130 g/ml). In both hepatic and renal lipoproteins apoA-I was found not only in HDL but also in the other lipoproteins. Immunohistochemical analysis of kidney sections showed that apoB and apoA-I were present almost exclusively in the epithelial cells of proximal and distal convoluted tubules. Thus apoB and apoA-I synthesized by the epithelial cells of the proximal and dis tal convoluted tubules of chick kidneys are secreted as constituents of lipoprotein particles floating within the density range of plasma lipoproteins. These observations suggest that in the chick, the kidneys may contribute to the plasma lipoprotein pool.
1997
- Heterozygous familial hypobetalipoproteinemia associated with fatty liver
[Recensione in Rivista]
Tarugi, Patrizia Maria; A., Lonardo
abstract
NO ABSTRACT AVAILABLE
1996
- Fatty liver in heterozygous hypobetalipoproteinemia caused by a novel truncated form of apolipoprotein B
[Articolo su rivista]
Tarugi, Patrizia Maria; A., Lonardo; G., Ballarini; A., Grisendi; M., Pulvirenti; A., Bagni; CALANDRA BUONAURA, Sebastiano
abstract
Fatty liver has been anecdotally associated with heterozygous hypobetalipoproteinemia. The aim of this study was to characterize the molecular defect in a subject with heterozygous hypobetalipoproteinemia (low-density lipoprotein cholesterol, 52 mg/dL; apolipoprotein [apo] B, 15 mg/dL) and otherwise unexplained fatty liver. Plasma lipoproteins were separated by ultracentrifugation, and apo B was analyzed by electrophoresis and immunoblotting. A fragment of genomic DNA corresponding to the 5' end of exon 26 of the apo B gene was amplified by polymerase chain reaction and sequenced. The plasma lipoproteins of the proband contained, besides normal apo B-100, a 200-kilodalton truncated apo B whose size suggested the presence of a mutation in exon 26 of the apo B gene. The nucleotide sequence of a fragment of the 5' end of exon 26 revealed that the proband was a heterozygote for a 14-nucleotide deletion, producing a frameshift resulting in a premature stop codon at residue 1768. This truncated apo B was named apo B-38.95. The proband's father was a carrier of the same mutation. Fatty liver in this subject with familiar heterozygous hypobetalipoproteinemia most likely results from the inability of apo B-38.95 to export lipids from hepatocytes into the blood stream. Heterozygous hypobetalipoproteinemia should be considered in a hypolipidemic subject with an otherwise unexplained fatty liver.
1996
- Synthesis and secretion of B-100 and A-I apolipoproteins in response to the changes of intracellular cholesteryl ester content in chick liver
[Articolo su rivista]
Tarugi, Patrizia Maria; S., Nicolini; G., Ballarini; L., Marchi; C., Duvigneau; P., Tartoni; CALANDRA BUONAURA, Sebastiano
abstract
We investigated in the chick whether the diet-induced changes of the hepatic content of cholesteryl esters (CE) influence the synthesis and the secretion of apoB- and apoA-I-containing lipoproteins. Control chicks received a low cholesterol diet for 2 (SD-1), 4 (SD-2), or 7 (SD-3) weeks; the chicks in the experimental groups received a cholesterol-rich diet for 2 weeks and were killed at the end of the cholesterol feeding (CH-F), and after 2 (CH-D) or 5 (CH-DD) weeks of a low cholesterol diet. Hepatic CE content in CH-F chicks was 30-fold that observed in controls, but returned to the control level after 5 weeks of cholesterol depletion (CH-DD). The incorporation of S-35-labeled amino acids into cell and medium apoB and apoA-I was measured in liver slices. Intracellular S-35-labeled apoB was similar in all groups whereas medium S-35-labeled apoB was 2-fold higher in CH-F than in controls (SD-I). Pulse-chase experiments showed that radioactive apoB secreted by CH-F chicks at 120 min of chase was 2 times that of SD-1 chicks. This increased secretion of apoB was not found in CH-D chicks. In H-F chicks, the intracellular and medium S-35-labeled apoA-I were 2-fold the values found in controls (SD-1); apoA-I production returned to the control level only after 5 weeks of cholesterol depletion (CH-DD). The increased secretion of apoB and apoA-I in CH-F chicks was associated with an increased secretion of very low, intermediate, and low density lipoproteins containing newly synthesized apoB and apoA-I and of high density lipoproteins containing predominantly apoA-I. Thus, in response to hepatic CE accumulation induced by cholesterol feeding, a larger proportion of newly synthesized apoB is driven to the secretory pathway and more apoA-I is synthesized. This promotes an increased secretion of plasma lipoproteins that contribute to the removal of CE from the liver.
1994
- Apolipoprotein B-100 production and cholesteryl ester content in the liver of developing chick
[Articolo su rivista]
Tarugi, Patrizia Maria; Nicolini, S; Marchi, L; Ballarini, G; CALANDRA BUONAURA, Sebastiano
abstract
In the chick, the large cholesteryl ester (CE) store present in the liver during the last period of embryonic life increases at hatching and is rapidly depleted after 2-7 days of postnatal life. In this study we asked whether these changes were associated with variations in the hepatic production of apoB-containing lipoproteins. Liver slices taken from chicks at -3, 0 (hatching), 2, 4, 7, and 10 days of development were incubated with [35S]methionine in steady state incubations. ApoB production (cell + medium radioactivity) decreased from day -3 to day 0 (40%), increased at day 4 (54%), and decreased afterwards (45%). At day 4 the amount of 35S-labeled apoB-containing lipoproteins (VLDL-LDL) secreted into the medium was 1.7- and 1.5-times that found at days 0 and 7, respectively; the radioactivity incorporated into medium HDL (containing predominantly apoA-I) was 1.7-times that found at days 0 and 7. The incubation of liver slices with [3H]oleate showed that CE production at days 4 and 7 was 58% and 33%, respectively, of that found at day 0. The percentage of newly synthesized hepatic CE secreted into medium lipoproteins was 2.4%, 3.1%, and 2.2% at days 0, 4, and 7, respectively. The percentage of lipoprotein CE present in VLDL-LDL ranged from 38% at day 0 to 21% at day 7, and that present in HDL ranged from 62% at day 0 to 79% at day 7. To define whether the changes in the production of apoA-I- and apoB-containing lipoproteins were due to variations in apoB and apoA-I synthesis, the initial synthetic rate (pulse-labeling) and the mRNA content of these apolipoproteins were investigated. The initial apoB synthetic rate decreased 1.5-fold from day -3 to day 0, remained stable up to day 7, and decreased at day 10. Hepatic apoB mRNA followed a similar trend. The synthesis of apoA-I increased 2-fold from days -3/2 up to day 4 and did not change afterwards. In conclusion the increased hepatic CE content at hatching reflects a decreased production of apoB, while the depletion of CE observed from day 2 to day 7 is associated with an increased production of both apoB- and apoA-I-containing lipoproteins. The decreased apoB production at hatching is due to a decreased apoB synthesis whereas the increased apoB production at day 4 appears to be related to a post-translational event.
1994
- Effect of a thromboxane A2 synthase inhibitor on the dyslipoproteinemia of an inbred rat strain with spontaneous age-related nephrotic syndrome
[Articolo su rivista]
Tarugi, Patrizia Maria; Nicolini, S.; Albertazzi, L.; Marchi, L.; CALANDRA BUONAURA, Sebastiano; Salvati, P.
abstract
We have previously shown that the administration of a thromboxane A(2) (TXA(2)) synthase inhibitor (FCE 22178) reduced the progression of glomerular lesions and proteinuria in MNS rats, an inbred strain which develops an age-related nephrotic syndrome. In the present study we investigated the effect of FCE 22178 on the plasma lipoproteins of MNS rats at 28 weeks of age (with mild proteinuria and moderate dyslipoproteinemia) and at 48 weeks of age (with heavy proteinuria and severe dyslipoproteinemia). Drug treatment reduced proteinuria (by 70% and 36% at 28 and 48 weeks of age, respectively) plasma cholesterol (by 36% and 27% at 28 and 48 weeks of age, respectively) and prevented the decrease of plasma albumin observed in untreated rats (C-MNS) 48 weeks old. In treated rats (T-MNS), the decrease of proteinuria wets positively correlated with that of plasma cholesterol. FCE 22178 reduced the elevation in plasma HDL(1) (by 17.4%) and HDL(2) levels (by 30%), a key feature of nephrotic dyslipoproteinemia in the rat. From 28 to 48 weeks of age plasma apo A-I and apo E increased 217% and 128%, respectively, in C-MNS rats and 191% and 121%, respectively, in T-MNS-rats. A significant increase of apo A-I/apo E ratio was found in C-MNS rats from 28 (2.28+/-0.36) to 48 weeks of age (3.84+/-0.9) but not in T-MNS rats. FCE 22178 altered the lipid composition of VLDL and HDL(2) by reducing the content of cholesteryl esters and increasing that of free cholesterol and phospholipids. These findings suggest that the beneficial effect of FCE 22178 on the dyslipoproteinemia of nephrotic MNS rats is secondary to the amelioration in kidney function and to the reduction of proteinuria produced by this drug.
1993
- SYNTHESIS AND SECRETION OF APOLIPOPROTEIN-A-I
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
1992
- Sequential expression during postnatal development of specific markers of junctional and free sarcoplasmic reticulum in chicken pectoralis muscle.
[Articolo su rivista]
Damiani, E; Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Margreth, A.
abstract
Skeletal muscle sarcoplasmic reticulum comprises two distinct membrane domains, i.e., the Ca(2+)-pump membrane, corresponding mainly to longitudinal tubules, and the junctional membrane of the terminal cisternae containing the ryanodine receptor/Ca(2+)-release channel. Additional minor proteins previously shown in rabbit fast-twitch skeletal muscle to fractionate selectively to each membrane domain comprise 160- and 53-kDa glycoproteins and 170-kDa low-density lipoprotein (LDL)-binding protein, respectively (Damiani and Margreth, 1991, Biochem. J. 277, 825-832). We report evidence in chicken pectoralis, a predominantly fast muscle, on two closely immunologically related glycoproteins, a minor component of 130-kDa and a major 53-kDa protein. In contrast to the seemingly highly conserved structure of this protein, our results show marked differences in mobilities for chicken 125I-LDL that were detected as a 130- to 116-kDa protein doublet after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, although being otherwise indistinguishable from rabbit 170-kDa protein in LDL-binding characteristics, as well as for preferential association to junctional terminal cisternae. Chicken Ca(2+)-ATPase, although being extensively homologous to rabbit Ca(2+)-ATPase, is shown to be less active and to differ slightly in electrophoretic properties. We have investigated the time course of expression of the specific protein components of longitudinal and of junctional sarcoplasmic reticulum in chick pectoralis muscle from late embryonic development up to 2 months after hatching. Coincident with the posthatching increase in membrane density of high-affinity [3H]ryanodine-binding sites in muscle, both calsequestrin and the species-specific LDL-binding protein(s) are detected in increasing amounts, using ligand blot techniques. In contrast, the appearance and steady accumulation in muscle of Ca(2+)-ATPase, like the time-correlated increase of sarcoplasmic reticulum glycoproteins, are relatively delayed, the most striking changes occurring from 1 week after hatching onward. The sequential expression in chick developing muscle of proteins selectively associated with the junctional terminal cisternae and with longitudinal sarcoplasmic reticulum, respectively, argues for a similar morphogenetic program in avian and mammalian species and, to account for that, for the existence of common epigenetic differentiating influences on the expression of sarcoplasmic reticulum protein genes.
1991
- Dyslipoproteinemia in an inbred rat strain with spontaneous chronic progressive nephrotic syndrome
[Articolo su rivista]
Tarugi, Patrizia Maria; Nicolini, S.; Albertazzi, L.; Calandra, S.; Salvati, P.
abstract
Rats of the Milan Normotensive Strain (MNS) develop a dyslipoproteinemia that is associated with a spontaneous, age-dependent and slowly progressive nephropathy characterized by proteinuria and hypoalbuminemia (nephrotic syndrome). We assumed that the MNS strain might be a suitable model for studying the features of nephrotic dyslipoproteinemia and its relationship with proteinuria, hypoalbuminemia, and hepatic apolipoprotein production. Plasma lipoproteins were investigated in MNS rats at various ages (4-48 weeks) and in another rat strain (Milan Hypertensive Strain, MHS), genetically related to MNS but free of nephropathy, that was used as control. In MNS rats, abnormal proteinuria was detectable at 20 weeks and increased 2-fold up to 34 weeks with no reduction of plasma albumin (compensated stage). During this stage we found increased levels of plasma cholesterol (+ 34%), high density lipoprotein-1 (HDL1) (+ 73%), and HDL2 (+ 31%) that were positively correlated with proteinuria but not with plasma albumin. The later stage (34-48 weeks) (nephrotic stage) was characterized by a further increase of proteinuria, moderate hypoalbuminemia (- 25%), a 2-fold increase of plasma cholesterol, triacylglycerols, low density lipoprotein (LDL), and HDL1, and a 1.2-fold increase of HDL2. In this stage the levels of LDL, HDL1, and HDL2 were positively correlated with proteinuria, and negatively correlated with plasma albumin. The most striking change in apolipoproteins was a progressive increase of the relative content of apoA-I in HDL (in 48-week-old MNS rats the A-I/E ratio was 3-fold that found in MHS rats) that was associated with a similar increase of plasma apoA-I. None of these lipoprotein changes were observed in age-matched MHS rats. At the end of the compensated stage, the hepatic levels of A-I, B, A-II, and albumin mRNA were 5.3-, 3.5-, 1.3-, and 2.0-fold, respectively, those found in age-matched MHS rats. During the nephrotic stage, albumin mRNA continued to increase, whereas A-I, B, and A-II mRNAs decreased toward the levels found in age-matched MHS rats. Thus, nephrotic dyslipoproteinemia in MNS rats starts to develop in the compensated stage before the onset of hypoalbuminemia, is characterized by an early elevation of HDL1 + HDL2, and is associated with an increased content of hepatic mRNAs of some apolipoproteins, especially apoA-I. The slow progression of nephrotic syndrome with the long-standing proteinuria and no reduction in plasma albumin renders the MNS strain the most suitable animal model for the study of the effect of proteinuria on plasma lipoprotein metabolism.
1991
- Influence of age-related nephropathy on plasma lipoproteins of the aging rat
[Articolo su rivista]
Calandra, S.; Tarugi, P.
abstract
1991
- Synthesis and secretion of apolipoprotein A-I by chick skin.
[Articolo su rivista]
Tarugi, Patrizia Maria; Albertazzi, L; Nicolini, S; Ottaviani, Enzo; CALANDRA BUONAURA, Sebastiano
abstract
Chick skin slices were incubated with [35S]methionine and labeled apoA-I was immunoprecipitated from incubation medium and tissue homogenate. ApoA-I accounted for approximately 13 and 2.5% of radioactive medium and cell proteins, respectively. After ultracentrifugation of the medium, 55% of labeled apoA-I was found as a constituent of lipoproteins (d less than 1.210 g/ml) and 45% in a lipid-poor form (1.210-1.260 g/ml). To ascertain whether this large proportion of lipid-poor apoA-I was due to a dissociation of this peptide from medium lipoproteins during ultracentrifugation, labeled incubation medium was applied to an anti-chick apoA-I immunoaffinity column. The material bound to the column was analyzed by nondenaturing polyacrylamide gradient gel electrophoresis and found to contain three subpopulations of lipoproteins with a particle size of 12, 11, and 9 nm, respectively. The radioactivity of these subpopulations accounted for 82% of total radioactive medium apoA-I. ApoA-I was localized by immunohistochemistry in the viable cells of the epidermis and in the stratum corneum. Rat skin slices were found to synthesize and secrete apoE but no apoA-I. ApoA-I and apoE secreted by chick and rat skin, respectively, may play a role in the secretion of lipids from the differentiating keratinocytes and thus contribute to the formation of the hydrophobic barrier of the skin.
1990
- Absence of apolipoprotein B-48 in the chick, Gallus domesticus
[Articolo su rivista]
Tarugi, Patrizia Maria; Albertazzi, L; Nicolini, S; CALANDRA BUONAURA, Sebastiano
abstract
This study was designed to investigate: a) whether multiple forms of apoB are present in chick plasma lipoproteins; and b) which forms of apoB are produced in vitro by liver and intestine at various stages of pre- and post-natal development. Plasma lipoproteins of d less than 1.019 g/ml, isolated from fasted and nonfasted chicks, contained exclusively the high molecular weight apoB form (apoB-100) that comigrated with human and rat apoB-100 on SDS-PAGE gel. No apoB-48 was detected either in overloaded Coomassie blue-stained gels or after immunoblotting. ApoB-100 but no apoB-48 was found in portomicrons, the triglyceride-rich lipoproteins equivalent to chylomicrons, that in the chick are transported via the porto-mesenteric venous system. To ascertain whether a minute amount of apoB-48 was present in chick plasma, [35S]methionine was injected intraduodenally and the 35S-labeled d less than 1.019 g/ml plasma lipoproteins were isolated 45 min later from the systemic and the porto-mesenteric circulation. Only apoB-100 was found to be labeled in these lipoproteins. Cholesterol feeding did not induce the appearance of apoB-48 in plasma despite a marked accumulation of cholesterol-rich d less than 1.040 g/ml lipoproteins in the plasma. In vitro synthesis of apoB forms was studied in liver and intestinal slices isolated from chick embryos (8 and 5 days before hatching), newly hatched chicks (2 and 7 days after hatching), and young chicks (21 days old) that were incubated in the presence of [35S]methionine. At each stage of development, liver slices secreted predominantly apoB-100. Intestinal slices of newly hatched and young chicks secreted two forms of apoB: apoB-100 and an additional form with an electrophoretic mobility similar to rat plasma apoB-95. No apoB-48 was synthesized or secreted by the intestine. Our results indicate that the absence of apoB-48 in chick plasma reflects the lack of synthesis of this peptide in the intestine. It is conceivable that in chick intestine the recently described molecular mechanism responsible for the co/posttranscriptional modification of apoB mRNA leading to the formation of apoB-48 is lacking or defective.
1990
- Biochemistry of lipids and lipoproteins
[Articolo su rivista]
Calandra, S.; Tarugi, P.
abstract
1989
- Effect of development on apo A-I gene expression in the chick
[Relazione in Atti di Convegno]
Calandra, S.; Tarugi, P.
abstract
1989
- Plasma lipoproteins, tissue cholesterol overload, and skeletal muscle apolipoprotein A-I synthesis in the developing chick.
[Articolo su rivista]
Tarugi, Patrizia Maria; Reggiani, D; Ottaviani, Enzo; Ferrari, S; Tiozzo, Roberta; CALANDRA BUONAURA, Sebastiano
abstract
In the present study we investigated the changes of plasma lipids, lipoproteins, and tissue lipids that occur during the late embryonic life (5 days before hatching) and the postnatal period (0, 2, 7, 14, and 30 days after hatching) of the chick. The chick emerges from the egg with extreme hypercholesterolemia associated with a high level of cholesterol-rich VLDL + IDL. The density gradient profile of plasma lipoproteins showed that the concentrations of VLDL + IDL and LDL decreased during the first week of postnatal life, whereas HDL concentration increased sharply around hatching and remained stable afterwards. All plasma lipoprotein classes of the newborn chick (2 days from hatching) were enriched in cholesterol and cholesteryl esters; 2 weeks after hatching, the relative amount of cholesterol and cholesteryl esters decreased. In the newborn chick, plasma VLDL + IDL consisted of two populations of cholesteryl ester-rich lipoproteins: the main one (designated apoB-VLDL) contained apoB and no apoA-I; the other (designated apoA-I-VLDL) contained predominantly apoA-I. In the newborn chick there was an accumulation of free and esterified cholesterol in the liver and, to a lesser extent, in the skeletal muscle. These cholesterol deposits were depleted 2 to 7 days after hatching. The depletion in skeletal muscle was preceded by and associated with a striking increase in the synthesis of apoA-I in this tissue, as demonstrated by immunological methods and apoA-I mRNA measurements. In addition, apoA-I-containing HDL were secreted in vitro by explants of skeletal muscle of the newborn chick. The synthesis of apoA-I in the skeletal muscle decreased to the level found in the adult animal 1 week after hatching. It is likely that the rise of HDL and apoA-I in plasma observed 1-2 days after hatching reflects the production of apoA-I-containing HDL by skeletal muscle. We suggest that the cholesterol overload in skeletal muscle might stimulate the production of apoA-I which, in turn, would promote the removal of cholesterol from this tissue. The hypothesis that metabolic stimuli play a role in inducing apoA-I synthesis in skeletal muscle is supported by the observation that feeding the newborn chick a diet rich in proteins and lipids and free of carbohydrates delays the fall of apoA-I mRNA which normally occurs 1 week after hatching
1989
- Purification of an induced bacterial agglutinin in the freshwater snail planorbarius corneus (L.) (gastropoda, pulmonata)
[Articolo su rivista]
Ottaviani, E.; Tarugi, P.
abstract
An induced agglutinin was observed in Planorbarius corneus after challenge with living Staphylococcus aureus. Purified agglutinin has a MW of about 330-350 kilodaltons and shows an agglutinin titer of 128. This agglutinin does not present antibacterial activity. © 1989 Taylor & Francis Group, LLC.
1987
- Effect of sulodexide, a heparin-like compound, on experimental atherosclerosis in the rabbit
[Articolo su rivista]
Tarugi, P.; Tiozzo-Costa, R.; Barbanti, M.
abstract
1987
- The complete sequence of chick apolipoprotein AI mRNA and its expression in the developing chick
[Articolo su rivista]
Ferrari, Stefano; Tarugi, Patrizia Maria; Drusiani, E; CALANDRA BUONAURA, Sebastiano; Fregni, M.
abstract
The nucleotide (nt) sequence analysis of a full-length cDNA for chick apolipoprotein AI (Apo-AI) shows an open reading frame (ORF) of 792 nt, coding for a 264-aa protein. RNase mapping and sequence analysis of the 3' end show that apo-AI mRNA consists of at least two different species of 985 and 996 nt, respectively. During the embryonic life of the chick apo-AI mRNA is found in high concentration only in the liver, while its level in the intestine, the major Apo-AI producing organ in the adult, becomes significant only after hatching. This switch from liver to intestine, as primary site of apo-AI mRNA synthesis, takes place about ten days after hatching. The developmental control of the tissue levels of apo-AI mRNA is particularly evident in the skeletal muscle, where this mRNA species is present at high level only immediately after hatching. Preliminary evidence suggests that the time-limited rise in muscle apo-AI mRNA might be due to an increased rate of transcription.
1986
- Changes in apolipoprotein A-I mRNA level in the liver of rats with experimental nephrotic syndrome
[Articolo su rivista]
Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Chan, L.
abstract
In previous studies we had shown that: one of the most specific feature of hyperlipoproteinemia found in rats with experimental nephrotic syndrome is the accumulation of apolipoprotein A-I-rich HDL in plasma and this disorder is associated with an overproduction of apolipoprotein A-I by the liver. The present study was designed to investigate whether the increased hepatic synthesis of apolipoprotein A-I was due to an accumulation of functionally active apolipoprotein A-I mRNA in liver of nephrotic rats. Hepatic mRNA was translated in vitro by rabbit reticulocyte lysate in the presence of [35S]methionine and in vitro synthesized apolipoprotein A-I, albumin and apolipoprotein E were immunoprecipitated by specific rabbit IgG. In nephrotic rats the amount of in vitro synthesized apolipoprotein A-I was almost twice that found in the controls, suggesting that functionally active apolipoprotein A-I mRNA was increased in liver of nephrotic rats. To confirm that this difference in apolipoprotein A-I mRNA activity was due to an actual increase of hepatic apolipoprotein A-I mRNA sequences, we performed nucleic acid hybridization experiments (northern blot) using several cloned cDNA probes (rat and human apolipoprotein A-I, rat apolipoprotein E and apolipoprotein A-II). The results indicate that in nephrotic rats the amount of hybridizable apolipoprotein A-I mRNA sequences was about 3-fold higher than that in controls. In contrast, there was no difference in the amount of hybridizable apolipoprotein A-II and apolipoprotein E mRNA sequences, indicating that the change in apolipoprotein A-I mRNA induced by the nephrotic state was specific for this mRNA.
1986
- Hepatic synthesis of apolipoprotein AI in rats with nephrotic syndrome. Changes in hepatic mRNA for ApoAI
[Relazione in Atti di Convegno]
Calandra, S.; Tarugi, P.
abstract
1986
- Isolation and characterization of an agglutinin present in the haemolymph of the freshwater snail Planorbarius corneus (L.) (Gastropoda, pulmonata)
[Articolo su rivista]
Ottaviani, E.; Tarugi, P.
abstract
1. 1. An agglutinin was isolated from the haemolymph of Planorbarius corneus by affinity chromatography on Sephadex gel G 150. 2. 2. Molecular weight of the agglutinin as determined by polyacrylamide gel electrophoresis was 130,000 daltons. 3. 3. The agglutinin is a glycoprotein. 4. 4. The presence of taurine and N-acetylmuramic acid is discussed. © 1986.
1986
- Isolation of a cDNA clone for chick intestinal apolipoprotein AI (Apo-AI) and its use for detecting apo-AI mRNA expression in several chick tissues.
[Articolo su rivista]
Ferrari, Stefano; Drusiani, E; CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria
abstract
Three cDNA clones for chick apolipoprotein AI (Apo-AI), the major protein component of plasma high-density lipoproteins, have been isolated. The identity of the clones has been established first by screening a cDNA library in the pEX1 expression vector with anti-Apo-AI antibodies, second by Western blot analysis of the proteins expressed by positive clones. The use of the clone containing the largest, presumably full-size, cDNA insert (apo5C12) in molecular hybridization experiments confirms that apo-AI mRNA is expressed mainly in chick small intestine and liver. Furthermore, we provide evidence that brain, heart and skeletal muscle also synthesize significant amounts of apo-AI mRNA. The Southern-blot hybridization pattern of the restriction-enzyme-digested chick DNA with the apo5C12 DNA is consistent with there being a single copy of the apo-AI gene.
1985
- Isoforms of rat apolipoprotein A-I isolated from the lipoproteins of hepatic Golgi apparatus and plasma.
[Articolo su rivista]
Tarugi, Patrizia Maria; Ghisellini, Margherita; Pecorari, M; Brugni, N; CALANDRA BUONAURA, Sebastiano
abstract
We compared apo A-I isolated from the lipoproteins of the Golgi apparatus of rat liver with apo A-I found in plasma lipoproteins. Golgi apo A-I consists of 3 main isoforms with a molecular weight of approximately 28000 and isoelectric points (pI) of 5.97, 5.88 and 5.76, respectively. Plasma apo A-I consists of 4 major and 3 minor isoforms with a molecular weight of 27000. The pI of the major isoforms (numbered 4-7) is 5.88, 5.80, 5.70 and 5.60, respectively. In order to investigate which of the plasma isoforms derived directly from Golgi apo A-I, [35S]methionine was injected into the portal vein and Golgi and plasma apo A-I were isolated shortly thereafter. While all Golgi isoforms were labelled only 3 isoforms of plasma apo A-I (namely isoforms 5, 6 and 7) were found to be labelled. The major plasma isoform (isoform 4 which accounts for more than 60% of apo A-I mass of plasma HDL) was found to be unlabelled. However, when 35S plasma lipoproteins newly secreted by the liver were incubated in vitro in the presence of heparinized plasma, labelled isoform 4 appeared suggesting that heparinized plasma contained some factor capable of converting isoforms 5-7 into isoform 4. This plasma factor appears to be a protease as the in vitro formation of isoform 4 is prevented by protease inhibitors.
1984
- Separation of the isoprotein forms of apoprotein A-I of rat, rabbit and human HDL by combined isoelectrofocusing and SDS-polyacrylamide gel electrophoresis.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Ghisellini, Margherita
abstract
The distribution and the relative content of the isoprotein forms (isoforms) of apoprotein A-I (apo A-I) of HDL isolated from rat, rabbit and human plasma were studied by combined isoelectrofocusing and SDS-polyacrylamide gel electrophoresis. Rat apo A-I consists of seven isoforms having the same molecular weight (27,000) and moving in the 6.44-5.58 pH range. Isoforms 4, 5 and 6 are the major ones. Both rat HDL2 (1.090-1.210 g/ml) and purified rat apo A-I contain additional minor bands (designated 4a, 5a and 6a) which have the same isoelectric point as isoforms 4-6 but higher molecular weight (27,900). It is suggested that they might represent precursors of the main apo A-I isoforms. Rabbit apo A-I contains five isoforms focusing in the 5.69-5.34 pH range. Isoform 4 accounts for about 90% of apo A-I mass. Human apo A-I consists of five isoforms focusing in the pH range 5.91-5.0. Isoforms 3 and 4 are the main ones: their respective contents show high degrees of individual variation.
1983
- Plasma and urine lipoproteins during the development of nephrotic syndrome induced in the rat by adriamycin.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Ghisellini, Margherita; Gherardi, E.
abstract
The changes of plasma lipoproteins which occur during the development of nephrotic syndrome induced in the rat were investigated by the administration of the antineoplastic drug adriamycin. Rats received a single intravenous injection of the drug (7.5 mg/Kg) and were sacrificed 5, 10, 15, 20, 25, and 30 days after treatment. By monitoring plasma and urine albumin, four stages in the development of nephrosis were identified: (1) a prenephrotic stage, (2) a mild nephrosis with moderate albuminuria and hypoalbuminemia; (3) a severe nephrosis with massive albuminuria and severe hypoalbuminemia; and (4) a recovery stage in which plasma albumin showed the tendency to increase. Apart from a mild elevation of plasma triacylglycerols and VLDL observed as early as Day 5, no changes in plasma cholesterol and in the other lipoprotein classes were observed at the stage of mild nephrosis (Day 10). However, as the disease became more severe (Day 15-25) there was a striking increase of HDL1 (1.050-1.090 g/ml) and, above all, of HDL2 (1.090-1.210 g/ml). VLDL and LDL also increased but at a later stage. The elevation of HDL1 and HDL2 was associated with an increase of apolipoprotein A-I in plasma (fourfold increase). Moreover, the relative content of this apolipoprotein in HDL1 and HDL2 increased as the disease progressed from mild to severe, so that in severely nephrotic rats HDL1 and HDL2 contained almost exclusively A-I and C apolipoproteins. HDL enriched in apolipoprotein A-I were also found in urine of severely nephrotic animals. Since these findings are similar to those previously described in nephrotic syndrome induced by puromycin aminonucleoside (Gherardi, E., and Calandra, S. (1982). Biochim. Biophys. Acta 710, 188.) the following conclusions can be drawn: (1) the key signs of nephrotic syndrome (albuminuria and hypoalbuminemia) precede the elevation of plasma lipoproteins; (2) the pattern of nephrotic hyperlipoproteinemia evolves as a function of the severity of the disease; (3) the accumulation of HDL enriched in apolipoprotein A-I represents an early and specific feature of nephrotic hyperlipoproteinemia in the rat
1983
- Plasma post-heparin lipolytic activity in rats with nephrotic syndrome
[Articolo su rivista]
Calandra, S.; Gottardi, E.; Tarugi, P.
abstract
1982
- Heavy metals and experimental atherosclerosis. Effect of lead intoxication on rabbit plasma lipoproteins.
[Articolo su rivista]
Tarugi, Patrizia Maria; CALANDRA BUONAURA, Sebastiano; Borella, Paola; Vivoli, Gianfranco
abstract
Previous studies have suggested that exposure to heavy metals may be a risk factor in coronary atherosclerotic heart disease in humans as well as in experimental animals. Little is known however on the mechanism underlying the effect of heavy metals on the development of atherosclerosis. In this study we tried to ascertain whether exposure to lead might: (a) alter plasma lipoprotein in normally fed rabbits; and (b) aggravate the hyperlipidemia usually found in cholesterol-fed animals. Rabbits were fed a normal diet or a diet containing 1% cholesterol in the presence or in the absence of 0.5% of lead subacetate for 45 days. This produced an accumulation of lead in plasma and bone. While in cholesterol-fed rabbits, lead exposure did not modify the plasma lipoprotein pattern, in normally fed animals it induced a striking elevation of cholesterol esters. This was associated with an increased concentration of VLDL (1.006 g/ml), LDL1 (1.006-1.020 g/ml), LDL2 (1.020-1.050 g/ml) and HDL1 (1.050-1.210 g/ml). These lipoproteins had an elevated content of cholesterol esters and apolipoprotein B. It is suggested that some of these lipoproteins may be important in the development of atherosclerosis in subjects chronically exposed to lead.
1982
- long term effects of end to side portocaval anastomosis on lipogenesis of rat liver
[Articolo su rivista]
Tarugi, Patrizia Maria; Battistini, Nino Carlo; S., Calandra; M., baccarani contri; I., pasquali rinchetti; P., Zanini; R., Maurotti; P., Vassanelli
abstract
abst is not avaible
1981
- Dyslipidemia in rats with hypothyroidism
[Articolo su rivista]
Battistini, Nino Carlo; R., Ferrari; Tarugi, Patrizia Maria; S., Calandra
abstract
abst is not availeble
1981
- Synthesis and secretion of lipids by the liver of hypothyroid rats
[Articolo su rivista]
Tarugi, Patrizia Maria; S., Calandra; D., Vezzani; Battistini, Nino Carlo; R., Ferrari
abstract
abst is not avaible
1980
- Effect of lipoprotein-X on cholesterol synthesis in isolated rat hepatocytes
[Articolo su rivista]
Tarugi, P.; Battistini, N.; Ferrari, R.
abstract
1980
- Plasma lipoproteins and lipids in hypothyroidism induced by propylthiouracil in rat
[Articolo su rivista]
Ferrari, R.; Battistini, N.; Tarugi, P.; Calandra, S.
abstract
1979
- Cholesterol synthesis in isolated rat hepatocytes in vitro effect of sterol and bile acids
[Articolo su rivista]
S., Calandra; Tarugi, Patrizia Maria; Battistini, Nino Carlo; F., Crovetti
abstract
abst is not avaible
1979
- Cholesterol synthesis in isolated rat hepatocytes: effect of homologous and heterologous serum lipoproteins.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Tarugi, Patrizia Maria; Battistini, Nino Carlo; Ferrari, Renata
abstract
The present study investigated the effect of serum lipoproteins on sterol synthesis by isolated rat hepatocytes. These cells were maintained in culture medium for 24 hr and incubated for the same period of time with increasing concentrations of serum lipoproteins (5-150 microgram of lipoprotein-protein per ml) isolated from different animal species. The viability of the cells was ascertained by their ability to synthesize cholesterol and protein and to secrete serum proteins into the medium. Rat VLDL and LDL did not alter sterol synthesis, which was stimulated instead by HDL. Rat serum chylomicrons were also ineffective. Human LDL significantly reduced the synthesis of sterols from both acetate and tritiated water; this effect was also induced by human VLDL to a reduced extent. VLDL isolated from hypercholesterolemic rabbit (VLDLC) strongly inhibited sterol synthesis from acetate but not from mevalonate. Cholesteryl-ester-rich VLDL isolated from a patient with type III hyperlipidemia (type III VLDL) were more effective than normal VLDL in suppressing sterol synthesis from acetate. The implications of these findings are discussed with regard to the possible role of cholesteryl-ester-rich lipoproteins on the in vivo regulation of sterol synthesis in the liver.
1979
- Failure of LP-X to suppress sterol synthesis in rat hepatocytes
[Articolo su rivista]
Battistini, N.; Tarugi, P.; Calandra, S.
abstract
1978
- Secretion of serum lipoproteins by isolated rat hepatocytes in culture. Effect of colchicine
[Articolo su rivista]
Battistini, N.; Tarugi, P.; Calandra, S.
abstract
1978
- Selective degradation of serum high and low density lipoproteins by isolated rat hepatocytes
[Articolo su rivista]
Calandra, S.; Tarugi, P.; Battistini, N.; Ferrari, R.
abstract
1977
- Chemical and morphological changes of rat plasma lipoproteins after a prolonged administration of diets containing olive oil and cholesterol.
[Articolo su rivista]
CALANDRA BUONAURA, Sebastiano; Pasquali Ronchetti, I; Gherardi, E; Fornieri, C; Tarugi, Patrizia Maria
abstract
No abstract available
1977
- Cholesterol synthesis in freshly isolated human leukocytes.
[Articolo su rivista]
Tarugi, Patrizia Maria; Romoli, V; Crovetti, F; CALANDRA BUONAURA, Sebastiano
abstract
Cholesterol synthesis has been studied in human leukocytes shortly after the isolation from healthy subjects. Not delipidated human serum reduced the cholesterol synthesis when added to the incubation medium. A similar effect was obtained when the leukocytes were incubated in the presence of physiological concentrations of low density lipoproteins.