101
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Reiner Ž. Triglyceride-Rich Lipoproteins and Novel Targets for Anti-atherosclerotic Therapy. Korean Circ J 2018; 48:1097-1119. [PMID: 30403015 PMCID: PMC6221868 DOI: 10.4070/kcj.2018.0343] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 10/22/2018] [Indexed: 12/23/2022] Open
Abstract
Although elevated serum low-density lipoprotein-cholesterol (LDL-C) is without any doubts accepted as an important risk factor for cardiovascular disease (CVD), the role of elevated triglycerides (TGs)-rich lipoproteins as an independent risk factor has until recently been quite controversial. Recent data strongly suggest that elevated TG-rich lipoproteins are an independent risk factor for CVD and that therapeutic targeting of them could possibly provide further benefit in reducing CVD morbidity, events and mortality, apart from LDL-C lowering. Today elevated TGs are treated with lifestyle interventions, and with fibrates which could be combined with omega-3 fatty acids. There are also some new drugs. Volanesorsen, is an antisense oligonucleotid that inhibits the production of the Apo C-III which is crucial in regulating TGs metabolism because it inhibits lipoprotein lipase (LPL) and hepatic lipase activity but also hepatic uptake of TGs-rich particles. Evinacumab is a monoclonal antibody against angiopoietin-like protein 3 (ANGPTL3) and it seems that it can substantially lower elevated TGs levels because ANGPTL3 also regulates TGs metabolism. Pemafibrate is a selective peroxisome proliferator-activated receptor alpha modulator which also decreases TGs, and improves other lipid parameters. It seems that it also has some other possible antiatherogenic effects. Alipogene tiparvovec is a nonreplicating adeno-associated viral vector that delivers copies of the LPL gene to muscle tissue which accelerates the clearance of TG-rich lipoproteins thus decreasing extremely high TGs levels. Pradigastat is a novel diacylglycerol acyltransferase 1 inhibitor which substantially reduces extremely high TGs levels and appears to be promising in treatment of the rare familial chylomicronemia syndrome.
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Affiliation(s)
- Željko Reiner
- Department of Internal Medicine, University Hospital Centre Zagreb, School of Medicine University of Zagreb, Zagreb, Croatia.
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102
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Lee CJ, Oum CY, Lee Y, Park S, Kang SM, Choi D, Jang Y, Lee JH, Lee SH. Variants of Lipolysis-Related Genes in Korean Patients with Very High Triglycerides. Yonsei Med J 2018; 59:148-153. [PMID: 29214790 PMCID: PMC5725353 DOI: 10.3349/ymj.2018.59.1.148] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 11/27/2022] Open
Abstract
We investigated the prevalence and characteristics of variants of five lipolysis-related genes in Korean patients with very high triglycerides (TGs). Twenty-six patients with TG levels >885 mg/dL were selected from 13545 Korean subjects. Five candidate genes, LPL, APOC2, GPIHBP1, APOA5, and LMF1, were sequenced by targeted next-generation sequencing. Predictions of functional effects were performed and matched against public databases of variants. Ten rare variants of three genes were found in nine (34.6%) patients (three in LPL, four in APOA5, and three in LMF1). Five were novel and all variants were suspected of being disease-causing. Nine were heterozygous, and one (3.8%) had a homozygous rare variant of LPL. Six common variants of four genes were observed in 25 (96.2%) patients (one in LPL, one in GPIHBP1, two in APOA5, and two in LMF1). The c.G41T variant of GPIHBP1 and c.G533T variant of APOA5 were most frequent and found in 15 (57.7%) and 14 (53.8%) patients, respectively. Rare homozygous variants of the genes were very uncommon, while diverse rare heterozygous variants were commonly identified. Taken together, most study subjects may be manifesting the combined effects of rare heterozygous variants and common variants.
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Affiliation(s)
- Chan Joo Lee
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Chi Yoon Oum
- Department of Biostatistics and Computing, The Graduate School, Yonsei University, Seoul, Korea
| | - Yunbeom Lee
- Department of Medicine, Graduate School, Kyung Hee University, Seoul, Korea
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, Kyung Hee University, Seoul, Korea
| | - Sungha Park
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Seok Min Kang
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Donghoon Choi
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Yangsoo Jang
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Ji Hyun Lee
- Department of Clinical Pharmacology and Therapeutics, College of Medicine, Kyung Hee University, Seoul, Korea.
| | - Sang Hak Lee
- Division of Cardiology, Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Cardiovascular Research Institute, Yonsei University College of Medicine, Seoul, Korea.
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103
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Li JJ, Chen YQ, Fan LL, Jin JY, Guo S, Xiang R. Microduplication of 10q26.3 in a Chinese hypertriglyceridemia patient. Mol Cell Probes 2017; 37:28-31. [PMID: 29129660 DOI: 10.1016/j.mcp.2017.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 10/18/2022]
Abstract
Hypertriglyceridemia (HTG) plays an important role in the development and progression of atherosclerosis. It is inherited in an autosomal dominant pattern with a frequency of approximately 1:1,000,000 worldwide. Previous study has demonstrated that more than six genes underlie this disorder. In addition, copy number variants (CNVs) including disease-causing genes also play a crucial role in it. In this study, we have employed SNP-ARRAY chip technology to detect the pathogenic CNVs in a HTG patient who carried no meaningful mutations in HTG candidate genes. And we identified a de novo CNV interstitial 134.7 kb duplication of chromosome region 10q26.3 containing CYP2E1. And this CNV also has been confirmed by Real-time PCR. CYP2E1 is a member of cytochrome P450 superfamily of enzymes which play an important role in fatty acid metabolism. Our study is consistent with previous research and further claimes that CNVs containing CYP2E1 may be related to HTG and obesity. Our study not only further confirmes the hypothesis that the CYP2E1 is a plausible candidate gene for HTG, but also may contribute to the diagnosis and treatment of these genomic diseases.
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Affiliation(s)
- Jing-Jing Li
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Ya-Qin Chen
- The Second Xiangya Hospital of Central South University, Changsha 410013, China
| | - Liang-Liang Fan
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Jie-Yuan Jin
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Shuai Guo
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China
| | - Rong Xiang
- The State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410013, China; The Second Xiangya Hospital of Central South University, Changsha 410013, China.
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104
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Teramoto R, Tada H, Kawashiri MA, Nohara A, Nakahashi T, Konno T, Inazu A, Mabuchi H, Yamagishi M, Hayashi K. Molecular and functional characterization of familial chylomicronemia syndrome. Atherosclerosis 2017; 269:272-278. [PMID: 29153744 DOI: 10.1016/j.atherosclerosis.2017.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 11/01/2017] [Accepted: 11/09/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND AIMS Familial chylomicronemia syndrome is a rare autosomal recessive disorder leading to severe hypertriglyceridemia (HTG) due to mutations in lipoprotein lipase (LPL)-associated genes. Few data exist on the clinical features of the disorder or on comprehensive genetic approaches to uncover the causative genes and mutations. METHODS Eight patients diagnosed with familial hyperchylomicronemia with recessive inheritance were included in this study (two males and six females; median age of onset 23.0 years; mean triglyceride level 3446 mg/dl). We evaluated their clinical features, including coronary artery disease using coronary computed tomography, and performed targeted next-generation sequencing on a panel comprising 4813 genes associated with known clinical phenotypes. After standard filtering for allele frequency <1% and in silico annotation prediction, we used three types of variant filtering to identify causative mutations: homozygous mutations in known familial hyperchylomicronemia-associated genes, homozygous mutations with high damaging scores in novel genes, and deleterious mutations within 37 genes known to be associated with HTG. RESULTS A total of 1810 variants out of the 73,389 identified with 94.3% mean coverage (×20) were rare and nonsynonymous. Among these, our schema detected four pathogenic or likely pathogenic mutations in the LPL gene (p.Ala248LeufsTer4, p.Arg270Cys, p.Ala361Thr, and p.Val227Gly), including one novel mutation and a variant of uncertain significance. Patients harboring LPL gene mutations showed no severe atherosclerotic changes in the coronary arteries, but recurrent pancreatitis with long-term exposure to HTG was observed. CONCLUSIONS These results demonstrate that LPL gene plays a major role in extreme HTG associated with hyperchylomicronemia, although the condition may not cause severe atherosclerosis.
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Affiliation(s)
- Ryota Teramoto
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Hayato Tada
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan.
| | - Masa-Aki Kawashiri
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Atsushi Nohara
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Takuya Nakahashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Tetsuo Konno
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Akihiro Inazu
- Department of Laboratory Science, Molecular Biochemistry and Molecular Biology, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan
| | - Hiroshi Mabuchi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Masakazu Yamagishi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
| | - Kenshi Hayashi
- Department of Cardiovascular and Internal Medicine, Kanazawa University, Graduate School of Medicine, Kanazawa, Japan
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105
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He C, Hu X, Jung RS, Larsson M, Tu Y, Duarte-Vogel S, Kim P, Sandoval NP, Price TR, Allan CM, Raney B, Jiang H, Bensadoun A, Walzem RL, Kuo RI, Beigneux AP, Fong LG, Young SG. Lipoprotein lipase reaches the capillary lumen in chickens despite an apparent absence of GPIHBP1. JCI Insight 2017; 2:96783. [PMID: 29046479 DOI: 10.1172/jci.insight.96783] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 09/11/2017] [Indexed: 12/17/2022] Open
Abstract
In mammals, GPIHBP1 is absolutely essential for transporting lipoprotein lipase (LPL) to the lumen of capillaries, where it hydrolyzes the triglycerides in triglyceride-rich lipoproteins. In all lower vertebrate species (e.g., birds, amphibians, reptiles, fish), a gene for LPL can be found easily, but a gene for GPIHBP1 has never been found. The obvious question is whether the LPL in lower vertebrates is able to reach the capillary lumen. Using purified antibodies against chicken LPL, we showed that LPL is present on capillary endothelial cells of chicken heart and adipose tissue, colocalizing with von Willebrand factor. When the antibodies against chicken LPL were injected intravenously into chickens, they bound to LPL on the luminal surface of capillaries in heart and adipose tissue. LPL was released rapidly from chicken hearts with an infusion of heparin, consistent with LPL being located inside blood vessels. Remarkably, chicken LPL bound in a specific fashion to mammalian GPIHBP1. However, we could not identify a gene for GPIHBP1 in the chicken genome, nor could we identify a transcript for GPIHBP1 in a large chicken RNA-seq data set. We conclude that LPL reaches the capillary lumen in chickens - as it does in mammals - despite an apparent absence of GPIHBP1.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Tara R Price
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | | | - Brian Raney
- University of California, Santa Cruz Genomics Institute and
| | - Haibo Jiang
- Department of Medicine and.,Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, Western Australia, Perth, Australia
| | - André Bensadoun
- Division of Nutritional Science, Cornell University, Ithaca, New York, USA
| | - Rosemary L Walzem
- Department of Poultry Science and Faculty of Nutrition, Texas A&M University, College Station, Texas, USA
| | - Richard I Kuo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | | | | | - Stephen G Young
- Department of Medicine and.,Department of Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
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106
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Abstract
It is now evident that elevated circulating levels of triglycerides in the non-fasting state, a marker for triglyceride (TG)-rich remnant particles, are associated with increased risk of premature cardiovascular disease (CVD). Recent findings from basic and clinical studies have begun to elucidate the mechanisms that contribute to the atherogenicity of these apoB-containing particles. Here, we review current knowledge of the formation, intravascular remodelling and catabolism of TG-rich lipoproteins and highlight (i) the pivotal players involved in this process, including lipoprotein lipase, glycosylphosphatidylinositol HDL binding protein 1 (GPIHBP1), apolipoprotein (apo) C-II, apoC-III, angiopoietin-like protein (ANGPTL) 3, 4 and 8, apoA-V and cholesteryl ester transfer protein; (ii) key determinants of triglyceride (TG) levels and notably rates of production of very-low-density lipoprotein 1 (VLDL1) particles; and (iii) the mechanisms which underlie the atherogenicity of remnant particles. Finally, we emphasise the polygenic nature of moderate hypertriglyceridemia and briefly discuss modalities for its clinical management. Several new therapeutic strategies to attenuate hypertriglyceridemia have appeared recently, among which those targeted to apoC-III appear to hold considerable promise.
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Affiliation(s)
- Geesje M Dallinga-Thie
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands. .,Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
| | - Jeffrey Kroon
- Department of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.,Department of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
| | - Jan Borén
- Department of Molecular and Clinical Medicine, University of Gothenburg and Sahlgrenska University Hospital, Gothenburg, Sweden
| | - M John Chapman
- INSERM and University of Pierre and Marie Curie, Pitie-Salpetriere University Hospital, 75651, Paris Cedex 13, France
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107
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Dron JS, Ho R, Hegele RA. Recent Advances in the Genetics of Atherothrombotic Disease and Its Determinants. Arterioscler Thromb Vasc Biol 2017; 37:e158-e166. [DOI: 10.1161/atvbaha.117.309934] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jacqueline S. Dron
- From the Department of Biochemistry (J.S.D, R.H., R.A.H.), Robarts Research Institute (J.S.D., R.H., R.A.H.), and Department of Medicine (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Rosettia Ho
- From the Department of Biochemistry (J.S.D, R.H., R.A.H.), Robarts Research Institute (J.S.D., R.H., R.A.H.), and Department of Medicine (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Robert A. Hegele
- From the Department of Biochemistry (J.S.D, R.H., R.A.H.), Robarts Research Institute (J.S.D., R.H., R.A.H.), and Department of Medicine (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
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108
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Alterations in plasma triglycerides lipolysis in patients with history of multifactorial chylomicronemia. Atherosclerosis 2017; 265:22-28. [DOI: 10.1016/j.atherosclerosis.2017.07.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/18/2017] [Accepted: 07/27/2017] [Indexed: 11/19/2022]
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109
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Buonuomo PS, Rabacchi C, Macchiaiolo M, Trenti C, Fasano T, Tarugi P, Bartuli A, Bertolini S, Calandra S. Incidental finding of severe hypertriglyceridemia in children. Role of multiple rare variants in genes affecting plasma triglyceride. J Clin Lipidol 2017; 11:1329-1337.e3. [PMID: 28951076 DOI: 10.1016/j.jacl.2017.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/18/2017] [Accepted: 08/25/2017] [Indexed: 12/20/2022]
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.
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Affiliation(s)
| | - Claudio Rabacchi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - Marina Macchiaiolo
- Rare Diseases and Medical Genetics, Bambino Gesù Children Hospital, Rome, Italy
| | - Chiara Trenti
- Department of Internal Medicine, Lipid Clinic, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy
| | - Tommaso Fasano
- Clinical Chemistry and Endocrinology Laboratory, IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy
| | - Patrizia Tarugi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - Andrea Bartuli
- Rare Diseases and Medical Genetics, Bambino Gesù Children Hospital, Rome, Italy
| | - Stefano Bertolini
- Department of Internal Medicine, University of Genova, Genova, Italy.
| | - Sebastiano Calandra
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia, Modena, Italy.
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110
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Krehbiel KA, Glew RH, Modi S, Vasef MA. Splenic sea-blue (ceroid) histiocytosis due to hypertriglyceridemia: Report of a case and review of literature. HUMAN PATHOLOGY: CASE REPORTS 2017. [DOI: 10.1016/j.ehpc.2016.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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111
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Severe hypertriglyceridemia in Japan: Differences in causes and therapeutic responses. J Clin Lipidol 2017; 11:1383-1392. [PMID: 28958672 DOI: 10.1016/j.jacl.2017.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 07/27/2017] [Accepted: 08/10/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Severe hypertriglyceridemia (>1000 mg/dL) has a variety of causes and frequently leads to life-threating acute pancreatitis. However, the origins of this disorder are unclear for many patients. OBJECTIVE We aimed to characterize the causes of and responses to therapy in rare cases of severe hypertriglyceridemia in a group of Japanese patients. METHODS We enrolled 121 patients from a series of case studies that spanned 30 years. Subjects were divided into 3 groups: (1) primary (genetic causes); (2) secondary (acquired); and (3) disorders of uncertain causes. In the last group, we focused on 3 possible risks factors for hypertriglyceridemia: obesity, diabetes mellitus, and heavy alcohol intake. RESULTS Group A (n = 20) included 13 patients with familial lipoprotein lipase deficiency, 3 patients with apolipoprotein CII deficiency, and other genetic disorders in the rest of the group. Group B patients (n = 15) had various metabolic and endocrine diseases. In Group C (uncertain causes; n = 86), there was conspicuous gender imbalance (79 males, 3 females) and most male subjects were heavy alcohol drinkers. In addition, 18 of 105 adult patients (17%) had histories of acute pancreatitis. CONCLUSION The cause of severe hypertriglyceridemia is uncertain in many patients. In primary genetic forms of severe hypertriglyceridemia, genetic diversity between populations is unknown. In the acquired forms, we found fewer cases of estrogen-induced hypertriglyceridemia than in Western countries. In our clinical experience, the cause of most hypertriglyceridemia is uncertain. Our work suggests that genetic factors for plasma triglyceride sensitivity to alcohol should be explored.
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112
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Lilley JS, Linton MF, Kelley JC, Graham TB, Fazio S, Tavori H. A case of severe acquired hypertriglyceridemia in a 7-year-old girl. J Clin Lipidol 2017; 11:1480-1484. [PMID: 28916403 DOI: 10.1016/j.jacl.2017.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 01/24/2023]
Abstract
We report a case of severe type I hyperlipoproteinemia caused by autoimmunity against lipoprotein lipase (LPL) in the context of presymptomatic Sjögren's syndrome. A 7-year-old mixed race (Caucasian/African American) girl was admitted to the intensive care unit at Vanderbilt Children's Hospital with acute pancreatitis and shock. She was previously healthy aside from asthma and history of Hashimoto's thyroiditis. Admission triglycerides (TGs) were 2191 mg/dL but returned to normal during the hospital stay and in the absence of food intake. At discharge, she was placed on a low-fat, low-sugar diet. She did not respond to fibrates, prescription fish oil, metformin, or orlistat, and during the following 2 years, she was hospitalized several times with recurrent pancreatitis. Except for a heterozygous mutation in the promoter region of LPL, predicted to have no clinical significance, she had no further mutations in genes known to affect TG metabolism and to cause inherited type I hyperlipoproteinemia, such as APOA5, APOC2, GPIHBP1, or LMF1. When her TG levels normalized after incidental use of prednisone, an autoimmune mechanism was suspected. Immunoblot analyses showed the presence of autoantibodies to LPL in the patient's plasma. Autoantibodies to LPL decreased by 37% while patient was on prednisone, and by 68% as she subsequently transitioned to hydroxychloroquine monotherapy. While on hydroxychloroquine, she underwent a supervised high-fat meal challenge and showed normal ability to metabolize TG. For the past 3 years and 6 months, she has had TG consistently <250 mg/dL, and no symptoms of, or readmissions for, pancreatitis.
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Affiliation(s)
| | - MacRae F Linton
- Department of Medicine, Vanderbilt University Medical Center, Atherosclerosis Research Unit, Nashville, TN, USA
| | - Jennifer C Kelley
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - T Brent Graham
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Sergio Fazio
- Department of Medicine, Center for Preventive Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
| | - Hagai Tavori
- Department of Medicine, Center for Preventive Cardiology, Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA.
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113
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Abstract
PURPOSE OF REVIEW Plasma triglycerides are routinely measured with a lipid profile, and elevated plasma triglycerides are commonly encountered in the clinic. The confounded nature of this trait, which is correlated with numerous other metabolic perturbations, including depressed high-density lipoprotein cholesterol (HDL-C), has thwarted efforts to directly implicate triglycerides as causal in atherogenesis. Human genetic approaches involving large-scale populations and high-throughput genomic assessment under a Mendelian randomization framework have undertaken to sort out questions of causality. RECENT FINDINGS We review recent large-scale meta-analyses of cohorts and population-based sequencing studies designed to address whether common and rare variants in genes whose products are determinants of plasma triglycerides are also associated with clinical cardiovascular endpoints. The studied loci include genes encoding lipoprotein lipase and proteins that interact with it, such as apolipoprotein (apo) A-V, apo C-III and angiopoietin-like proteins 3 and 4, and common polymorphisms identified in genome-wide association studies. Triglyceride-raising variant alleles of these genes showed generally strong associations with clinical cardiovascular endpoints. However, in most cases, a second lipid disturbance-usually depressed HDL-C-was concurrently associated. While the findings collectively shift our understanding towards a potential causal role for triglycerides, we still cannot rule out the possibilities that triglycerides are a component of a joint phenotype with low HDL-C or that they are but markers of deeper causal metabolic disturbances that are not routinely measured in epidemiological-scale genetic studies.
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Affiliation(s)
- Jacqueline S. Dron
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7 Canada
| | - Robert A. Hegele
- Department of Biochemistry, Schulich School of Medicine and Dentistry, Western University, London, ON Canada
- Robarts Research Institute, Schulich School of Medicine and Dentistry, Western University, 4288A-1151 Richmond Street North, London, ON N6A 5B7 Canada
- Department of Medicine, Schulich School of Medicine and Dentistry, Western University, London, ON Canada
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114
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GPIHBP1 autoantibodies in a patient with unexplained chylomicronemia. J Clin Lipidol 2017; 11:964-971. [PMID: 28666713 DOI: 10.1016/j.jacl.2017.05.017] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 05/23/2017] [Indexed: 12/28/2022]
Abstract
BACKGROUND GPIHBP1, a glycolipid-anchored protein of capillary endothelial cells, binds lipoprotein lipase (LPL) in the interstitial spaces and transports it to the capillary lumen. GPIHBP1 deficiency prevents LPL from reaching the capillary lumen, resulting in low intravascular LPL levels, impaired intravascular triglyceride processing, and severe hypertriglyceridemia (chylomicronemia). A recent study showed that some cases of hypertriglyceridemia are caused by autoantibodies against GPIHBP1 ("GPIHBP1 autoantibody syndrome"). OBJECTIVE Our objective was to gain additional insights into the frequency of the GPIHBP1 autoantibody syndrome in patients with unexplained chylomicronemia. METHODS We used enzyme-linked immunosorbent assays to screen for GPIHBP1 autoantibodies in 33 patients with unexplained chylomicronemia and then used Western blots and immunocytochemistry studies to characterize the GPIHBP1 autoantibodies. RESULTS The plasma of 1 patient, a 36-year-old man with severe hypertriglyceridemia, contained GPIHBP1 autoantibodies. The autoantibodies, which were easily detectable by Western blot, blocked the ability of GPIHBP1 to bind LPL. The plasma levels of LPL mass and activity were low. The patient had no history of autoimmune disease, but his plasma was positive for antinuclear antibodies. CONCLUSIONS One of 33 patients with unexplained chylomicronemia had the GPIHBP1 autoantibody syndrome. Additional studies in large lipid clinics will be helpful for better defining the frequency of this syndrome and for exploring the best strategies for treatment.
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The role of antisense oligonucleotide therapy against apolipoprotein-CIII in hypertriglyceridemia. ATHEROSCLEROSIS SUPP 2017; 30:19-27. [PMID: 29096837 DOI: 10.1016/j.atherosclerosissup.2017.05.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Increased triglyceride levels (higher than ∼1000 mg/dL) are associated with an increased risk for pancreatitis. Apolipoprotein-CIII (apo-CIII) plays a key role in the metabolism of triglycerides and triglyceride-rich lipoproteins. While loss of function mutations in the gene encoding apo-CIII (APOC3) are associated with low triglyceride levels and a decreased risk for cardiovascular disease (CVD), overexpression of APOC3 is associated with hypertriglyceridemia. Although many drugs such as fibrates, statins and omega-3 fatty acids modestly decrease triglyceride levels (and apo-CIII concentrations), there are many patients who still have severe hypertriglyceridemia and are at risk for pancreatitis and potentially CVD. The antisense oligonucleotide (ASO) against APOC3 mRNA volanesorsen (previously called ISIS 304801, ISIS-ApoCIIIRx and IONIS-ApoCIIIRx) robustly decreases both, apo-CIII production and triglyceride concentrations and is being currently evaluated in phase 3 trials. In this narrative review we present the currently available clinical evidence on the efficacy and safety of volanesorsen for the treatment of hypertriglyceridemia.
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Guardiola M, Ribalta J. Update on APOA5 Genetics: Toward a Better Understanding of Its Physiological Impact. Curr Atheroscler Rep 2017; 19:30. [DOI: 10.1007/s11883-017-0665-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Allan CM, Jung CJ, Larsson M, Heizer PJ, Tu Y, Sandoval NP, Dang TLP, Jung RS, Beigneux AP, de Jong PJ, Fong LG, Young SG. Mutating a conserved cysteine in GPIHBP1 reduces amounts of GPIHBP1 in capillaries and abolishes LPL binding. J Lipid Res 2017; 58:1453-1461. [PMID: 28476858 DOI: 10.1194/jlr.m076943] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 05/04/2017] [Indexed: 12/22/2022] Open
Abstract
Mutation of conserved cysteines in proteins of the Ly6 family cause human disease-chylomicronemia in the case of glycosylphosphatidylinositol-anchored HDL binding protein 1 (GPIHBP1) and paroxysmal nocturnal hemoglobinuria in the case of CD59. A mutation in a conserved cysteine in CD59 prevented the protein from reaching the surface of blood cells. In contrast, mutation of conserved cysteines in human GPIHBP1 had little effect on GPIHBP1 trafficking to the surface of cultured CHO cells. The latter findings were somewhat surprising and raised questions about whether CHO cell studies accurately model the fate of mutant GPIHBP1 proteins in vivo. To explore this concern, we created mice harboring a GPIHBP1 cysteine mutation (p.C63Y). The p.C63Y mutation abolished the ability of mouse GPIHBP1 to bind LPL, resulting in severe chylomicronemia. The mutant GPIHBP1 was detectable by immunohistochemistry on the surface of endothelial cells, but the level of expression was ∼70% lower than in WT mice. The mutant GPIHBP1 protein in mouse tissues was predominantly monomeric. We conclude that mutation of a conserved cysteine in GPIHBP1 abolishes the ability of GPIHBP1 to bind LPL, resulting in mislocalization of LPL and severe chylomicronemia. The mutation reduced but did not eliminate GPIHBP1 on the surface of endothelial cells in vivo.
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Affiliation(s)
- Christopher M Allan
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Cris J Jung
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Mikael Larsson
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Patrick J Heizer
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Yiping Tu
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Norma P Sandoval
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Tiffany Ly P Dang
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Rachel S Jung
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095
| | - Anne P Beigneux
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
| | - Pieter J de Jong
- Children's Hospital Oakland Research Institute, Oakland, CA 94609
| | - Loren G Fong
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095.
| | - Stephen G Young
- Departments of Medicine University of California Los Angeles, Los Angeles, CA 90095; Human Genetics, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095.
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Abstract
An elevated serum level of LDL cholesterol is a well-known risk factor for cardiovascular disease (CVD), but the role of elevated triglyceride levels is debated. Controversies regarding hypertriglyceridaemia as an independent risk factor for CVD have occurred partly because elevated triglyceride levels are often a component of atherogenic dyslipidaemia - they are associated with decreased levels of HDL cholesterol and increased levels of small dense LDL particles, which are highly atherogenic. Findings from several large studies indicate that elevated levels of triglycerides (either fasting or nonfasting) or, more specifically, triglyceride-rich lipoproteins and their remnants, are independently associated with increased risk of CVD. Possible mechanisms for this association include excessive free fatty acid release, production of proinflammatory cytokines, coagulation factors, and impairment of fibrinolysis. Therapeutic targeting of hypertriglyceridaemia could, therefore, reduce CVD and cardiovascular events, beyond the reduction achieved by LDL-cholesterol lowering. Elevated triglyceride levels are reduced with lifestyle interventions and fibrates, which can be combined with omega-3 fatty acids. Some new drugs are on the horizon, such as volanesorsen (which targets apolipoprotein C-III), pemafibrate, and others. However, CVD outcome studies with triglyceride-lowering agents have produced inconsistent results, meaning that no convincing evidence is available that lowering triglycerides by any approach can reduce mortality.
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Ram R, Wakil S, Muiya N, Andres E, Mazhar N, Hagos S, Alshahid M, Meyer B, Morahan G, Dzimiri N. A common variant association study in ethnic Saudi Arabs reveals novel susceptibility loci for hypertriglyceridemia. Clin Genet 2017; 91:371-378. [DOI: 10.1111/cge.12859] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/30/2016] [Accepted: 08/30/2016] [Indexed: 12/15/2022]
Affiliation(s)
- R. Ram
- Centre for Diabetes Research, The Harry Perkinsn Institute for Medical Research Perth WA Australia
- Centre for Medical ResearchUniversity of Western Australia Perth WA Australia
| | - S.M. Wakil
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - N.P. Muiya
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - E. Andres
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - N. Mazhar
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - S. Hagos
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - M. Alshahid
- King Faisal Heart InstituteKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - B.F. Meyer
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
| | - G. Morahan
- Centre for Diabetes Research, The Harry Perkinsn Institute for Medical Research Perth WA Australia
- Centre for Medical ResearchUniversity of Western Australia Perth WA Australia
| | - N. Dzimiri
- Genetics DepartmentKing Faisal Specialist Hospital and Research Centre Riyadh KSA
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Cefalù AB, Spina R, Noto D, Ingrassia V, Valenti V, Giammanco A, Fayer F, Misiano G, Cocorullo G, Scrimali C, Palesano O, Altieri GI, Ganci A, Barbagallo CM, Averna MR. Identification of a novel LMF1 nonsense mutation responsible for severe hypertriglyceridemia by targeted next-generation sequencing. J Clin Lipidol 2017; 11:272-281.e8. [PMID: 28391895 DOI: 10.1016/j.jacl.2017.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 12/28/2016] [Accepted: 01/02/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND Severe hypertriglyceridemia (HTG) may result from mutations in genes affecting the intravascular lipolysis of triglyceride (TG)-rich lipoproteins. OBJECTIVE The aim of this study was to develop a targeted next-generation sequencing panel for the molecular diagnosis of disorders characterized by severe HTG. METHODS We developed a targeted customized panel for next-generation sequencing Ion Torrent Personal Genome Machine to capture the coding exons and intron/exon boundaries of 18 genes affecting the main pathways of TG synthesis and metabolism. We sequenced 11 samples of patients with severe HTG (TG>885 mg/dL-10 mmol/L): 4 positive controls in whom pathogenic mutations had previously been identified by Sanger sequencing and 7 patients in whom the molecular defect was still unknown. RESULTS The customized panel was accurate, and it allowed to confirm genetic variants previously identified in all positive controls with primary severe HTG. Only 1 patient of 7 with HTG was found to be carrier of a homozygous pathogenic mutation of the third novel mutation of LMF1 gene (c.1380C>G-p.Y460X). The clinical and molecular familial cascade screening allowed the identification of 2 additional affected siblings and 7 heterozygous carriers of the mutation. CONCLUSIONS We showed that our targeted resequencing approach for genetic diagnosis of severe HTG appears to be accurate, less time consuming, and more economical compared with traditional Sanger resequencing. The identification of pathogenic mutations in candidate genes remains challenging and clinical resequencing should mainly intended for patients with strong clinical criteria for monogenic severe HTG.
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Affiliation(s)
- Angelo B Cefalù
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy; Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy.
| | - Rossella Spina
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy; Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy
| | - Davide Noto
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Valeria Ingrassia
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy; Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy
| | - Vincenza Valenti
- Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy
| | - Antonina Giammanco
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Francesca Fayer
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Gabriella Misiano
- Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy
| | - Gianfranco Cocorullo
- Unit of Emergency and General Surgery, Department of Surgical Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Chiara Scrimali
- Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy
| | - Ornella Palesano
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Grazia I Altieri
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Antonina Ganci
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Carlo M Barbagallo
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy
| | - Maurizio R Averna
- Dipartimento Biomedico di Medicina Interna e Specialistica (DIBIMIS), University of Palermo, Palermo, Italy; Molecular Biology Diagnostic Laboratory, Central Laboratory of Advanced Diagnosis and Biomedical Research (CLADIBIOR), AOUP "Paolo Giaccone", Palermo, Italy.
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Viecili PRN, da Silva B, Hirsch GE, Porto FG, Parisi MM, Castanho AR, Wender M, Klafke JZ. Triglycerides Revisited to the Serial. Adv Clin Chem 2017; 80:1-44. [PMID: 28431638 DOI: 10.1016/bs.acc.2016.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This review discusses the role of triglycerides (TGs) in the normal cardiovascular system as well as in the development and clinical manifestation of cardiovascular diseases. Regulation of TGs at the enzymatic and genetic level, in addition to their possible relevance as preclinical and clinical biomarkers, is discussed, culminating with a description of available and emerging treatments. Due to the high complexity of the subject and the vast amount of material in the literature, the objective of this review was not to exhaust the subject, but rather to compile the information to facilitate and improve the understanding of those interested in this topic. The main publications on the topic were sought out, especially those from the last 5 years. The data in the literature still give reason to believe that there is room for doubt regarding the use of TG as disease biomarkers; however, there is increasing evidence for the role of hypertriglyceridemia on the atherosclerotic inflammatory process, cardiovascular outcomes, and mortality.
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122
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Schwarzova L, Hubacek JA, Vrablik M. Genetic predisposition of human plasma triglyceride concentrations. Physiol Res 2016; 64:S341-54. [PMID: 26680667 DOI: 10.33549/physiolres.933197] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The issue of plasma triglyceride levels relative to the risk of development of cardiovascular disease, as well as overall mortality, has been actively discussed for many years. Like other cardiovascular disease risk factors, final plasma TG values have environmental influences (primarily dietary habits, physical activity, and smoking), and a genetic predisposition. Rare mutations (mainly in the lipoprotein lipase and apolipoprotein C2) along with common polymorphisms (within apolipoprotein A5, glucokinase regulatory protein, apolipoprotein B, apolipo-protein E, cAMP responsive element binding protein 3-like 3, glycosylphosphatidylinositol-anchored HDL-binding protein 1) play an important role in determining plasma TG levels.
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Affiliation(s)
- L Schwarzova
- Third Department of Internal Medicine, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
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Agrawal N, Freitas Corradi P, Gumaste N, Goldberg IJ. Triglyceride Treatment in the Age of Cholesterol Reduction. Prog Cardiovasc Dis 2016; 59:107-118. [PMID: 27544319 PMCID: PMC5364728 DOI: 10.1016/j.pcad.2016.08.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 08/15/2016] [Indexed: 01/28/2023]
Abstract
Cholesterol reduction has markedly reduced major cardiovascular disease (CVD) events and shown regression of atherosclerosis in some studies. However, CVD has for decades also been associated with increased levels of circulating triglyceride (TG)-rich lipoproteins. Whether this is due to a direct toxic effect of these lipoproteins on arteries or whether this is merely an association is unresolved. More recent genetic analyses have linked genes that modulate TG metabolism with CVD. Moreover, analyses of subgroups of hypertriglyceridemic (HTG) subjects in clinical trials using fibric acid drugs have been interpreted as evidence that TG reduction reduces CVD events. This review will focus on how HTG might cause CVD, whether TG reduction makes a difference, what pathophysiological defects cause HTG, and what options are available for treatment.
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Affiliation(s)
- Nidhi Agrawal
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY
| | - Patricia Freitas Corradi
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY
| | - Namrata Gumaste
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY
| | - Ira J Goldberg
- Division of Endocrinology, Diabetes and Metabolism, New York University School of Medicine, New York, NY.
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Patni N, Brothers J, Xing C, Garg A. Type 1 hyperlipoproteinemia in a child with large homozygous deletion encompassing GPIHBP1. J Clin Lipidol 2016; 10:1035-1039.e2. [DOI: 10.1016/j.jacl.2016.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Revised: 03/30/2016] [Accepted: 04/03/2016] [Indexed: 01/12/2023]
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Lamiquiz-Moneo I, Blanco-Torrecilla C, Bea AM, Mateo-Gallego R, Pérez-Calahorra S, Baila-Rueda L, Cenarro A, Civeira F, de Castro-Orós I. Frequency of rare mutations and common genetic variations in severe hypertriglyceridemia in the general population of Spain. Lipids Health Dis 2016; 15:82. [PMID: 27108409 PMCID: PMC4842266 DOI: 10.1186/s12944-016-0251-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 04/18/2016] [Indexed: 11/10/2022] Open
Abstract
Background Hypertriglyceridemia (HTG) is a common complex metabolic trait that results of the accumulation of relatively common genetic variants in combination with other modifier genes and environmental factors resulting in increased plasma triglyceride (TG) levels. The majority of severe primary hypertriglyceridemias is diagnosed in adulthood and their molecular bases have not been fully defined yet. The prevalence of HTG is highly variable among populations, possibly caused by differences in environmental factors and genetic background. However, the prevalence of very high TG and the frequency of rare mutations causing HTG in a whole non-selected population have not been previously studied. Methods The total of 23,310 subjects over 18 years from a primary care-district in a middle-class area of Zaragoza (Spain) with TG >500 mg/dL were selected to establish HTG prevalence. Those affected of primary HTG were considered for further genetic analisys. The promoters, coding regions and exon-intron boundaries of LPL, LMF1, APOC2, APOA5, APOE and GPIHBP1 genes were sequenced. The frequency of rare variants identified was studied in 90 controls. Results One hundred ninety-four subjects (1.04 %) had HTG and 90 subjects (46.4 %) met the inclusion criteria for primary HTG. In this subgroup, nine patients (12.3 %) were carriers of 7 rare variants in LPL, LMF1, APOA5, GPIHBP1 or APOE genes. Three of these mutations are described for the first time in this work. The presence of a rare pathogenic mutation did not confer a differential phenotype or a higher family history of HTG. Conclusion The prevalence of rare mutations in candidate genes in subjects with primary HTG is low. The low frequency of rare mutations, the absence of a more severe phenotype or the dominant transmission of the HTG would not suggest the use of genetic analysis in the clinical practice in this population. Electronic supplementary material The online version of this article (doi:10.1186/s12944-016-0251-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Itziar Lamiquiz-Moneo
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain.
| | - Cristian Blanco-Torrecilla
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Ana M Bea
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Rocío Mateo-Gallego
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Sofía Pérez-Calahorra
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Lucía Baila-Rueda
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Ana Cenarro
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Fernando Civeira
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain
| | - Isabel de Castro-Orós
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Avenida Isabel La Católica 1-3, 50009, Zaragoza, Spain.,Universidad de Zaragoza, Departamento de Bioquímica, Biología Molecular y Celular, 50009, Zaragoza, Spain
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Abstract
PURPOSE OF REVIEW This article summarizes the current evidence to support a role of sulfatase 2 (SULF2) in triglyceride-rich lipoprotein (TRL) metabolism and angiogenesis. RECENT FINDINGS Heparan sulfate proteoglycans (HSPG) are involved in the hepatic clearance of TRLs in mice and in humans. Different genetically modified mouse models have been instrumental to provide evidence that syndecan1, the core protein of HSPG, but also the degree of sulfation of the heparin sulfate chain, attached to syndecan 1, is important for hepatic TRL metabolism. Studies in humans demonstrate the regulating role of SULF2 in the hepatic uptake of TRL by HSPG and demonstrate the importance of 6-O-sulfation, modulated by SULF2, for HSPG function. The role of SULF2 in angiogenesis is illustrated by increased SULF2 mRNA expression in the stalk cells of angiogenic vascular sprouts that use fatty acids derived from TRL as a source for biomass production. Interestingly, SULF2 also interferes with HSPG-vascular endothelial growth factor binding, which impacts upon the angiogenic properties of stalk cells. SUMMARY SULF2 is a multifaceted protein involved in TRL homeostasis and angiogenesis. Future investigations should focus on the potential benefits of targeting SULF2 in atherosclerosis and angiogenesis.
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Affiliation(s)
- Marchien G Dallinga
- aDepartment of Ophthalmology bDepartment of Vascular cDepartment of Experimental Vascular Medicine, Academic Medical Center Amsterdam, University of Amsterdam, The Netherlands
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127
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Therapeutic Targets of Triglyceride Metabolism as Informed by Human Genetics. Trends Mol Med 2016; 22:328-340. [DOI: 10.1016/j.molmed.2016.02.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 12/24/2022]
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Clinical and genetic features of 3 patients with familial chylomicronemia due to mutations in GPIHBP1 gene. J Clin Lipidol 2016; 10:915-921.e4. [PMID: 27578123 DOI: 10.1016/j.jacl.2016.03.009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 12/30/2022]
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.
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De Castro-Orós I, Civeira F, Pueyo MJ, Mateo-Gallego R, Bolado-Carrancio A, Lamíquiz-Moneo I, Álvarez-Sala L, Fabiani F, Cofán M, Cenarro A, Rodríguez-Rey JC, Ros E, Pocoví M. Rare genetic variants with large effect on triglycerides in subjects with a clinical diagnosis of familial vs nonfamilial hypertriglyceridemia. J Clin Lipidol 2016; 10:790-797. [PMID: 27578109 DOI: 10.1016/j.jacl.2016.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 02/18/2016] [Indexed: 11/19/2022]
Abstract
BACKGROUND Most primary severe hypertriglyceridemias (HTGs) are diagnosed in adults, but their molecular foundations have not been completely elucidated. OBJECTIVE We aimed to identify rare dysfunctional mutations in genes encoding regulators of lipoprotein lipase (LPL) function in patients with familial and non-familial primary HTG. METHODS We sequenced promoters, exons, and exon-intron boundaries of LPL, APOA5, LMF1, and GPIHBP1 in 118 patients with severe primary HTG (triglycerides >500 mg/dL) and 53 normolipidemic controls. Variant functionality was analyzed using predictive software and functional assays for mutations in regulatory regions. RESULTS We identified 29 rare variants, 10 of which had not been previously described: c.(-16A>G), c.(1018+2G>A), and p.(His80Arg) in LPL; p.(Arg143Alafs*57) in APOA5; p.(Val140Ile), p.(Leu235Ile), p.(Lys520*), and p.(Leu552Arg) in LMF1; and c.(-83G>A) and c.(-192A>G) in GPIHBP1. The c.(1018+2G>A) variant led to deletion of exon 6 in LPL cDNA, whereas the c.(-16A>G) analysis showed differences in the affinity for nuclear proteins. Overall, 20 (17.0%) of the patients carried at least one allele with a rare pathogenic variant in LPL, APOA5, LMF1, or GPIHBP1. The presence of a rare pathogenic variant was not associated with lipid values, family history of HTG, clinical diagnosis, or previous pancreatitis. CONCLUSIONS Less than one in five subjects with triglycerides >500 mg/dL and no major secondary cause for HTG may carry a rare pathogenic mutation in LPL, APOA5, LMF1, or GPIHBP1. The presence of a rare pathogenic variant is not associated with a differential phenotype.
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Affiliation(s)
- Isabel De Castro-Orós
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain; Dpto. Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain.
| | - Fernando Civeira
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain
| | - María Jesús Pueyo
- Dpto. Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
| | - Rocío Mateo-Gallego
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain
| | - Alfonso Bolado-Carrancio
- Dpto. Biología Molecular. Facultad de Medicina, Universidad de Cantabria and Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Cantabria, Spain
| | - Itziar Lamíquiz-Moneo
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain
| | - Luis Álvarez-Sala
- Lipid Unit, Medicina Interna, Hospital Universitario Gregorio Marañón, RIC, Instituto de Salud Carlos III (ISCIII), Instituto de Investigación Sanitaria Gregorio Marañón and Dpto. Medicina, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Fernando Fabiani
- Departamento de Bioquímica Clínica, Hospital Universitario Virgen Macarena, Universidad de Sevilla, Sevilla, Spain
| | - Montserrat Cofán
- Servei d'Endocrinologia i Nutrició, Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Hospital Clínic, Barcelona and Ciber Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III (ISCIII), Barcelona, Spain
| | - Ana Cenarro
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón (IIS Aragón), Zaragoza, Spain
| | - José Carlos Rodríguez-Rey
- Dpto. Biología Molecular. Facultad de Medicina, Universidad de Cantabria and Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Santander, Cantabria, Spain
| | - Emilio Ros
- Servei d'Endocrinologia i Nutrició, Institut d'Investigacions Biomèdiques August Pi Sunyer (IDIBAPS), Hospital Clínic, Barcelona and Ciber Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III (ISCIII), Barcelona, Spain
| | - Miguel Pocoví
- Dpto. Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Zaragoza, Spain
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Julve J, Martín-Campos JM, Escolà-Gil JC, Blanco-Vaca F. Chylomicrons: Advances in biology, pathology, laboratory testing, and therapeutics. Clin Chim Acta 2016; 455:134-48. [PMID: 26868089 DOI: 10.1016/j.cca.2016.02.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 02/01/2016] [Accepted: 02/06/2016] [Indexed: 01/17/2023]
Abstract
The adequate absorption of lipids is essential for all mammalian species due to their inability to synthesize some essential fatty acids and fat-soluble vitamins. Chylomicrons (CMs) are large, triglyceride-rich lipoproteins that are produced in intestinal enterocytes in response to fat ingestion, which function to transport the ingested lipids to different tissues. In addition to the contribution of CMs to postprandial lipemia, their remnants, the degradation products following lipolysis by lipoprotein lipase, are linked to cardiovascular disease. In this review, we will focus on the structure-function and metabolism of CMs. Second, we will analyze the impact of gene defects reported to affect CM metabolism and, also, the role of CMs in other pathologies, such as atherothrombotic cardiovascular disease and diabetes mellitus. Third, we will provide an overview of the laboratory tests currently used to study CM disorders, and, finally, we will highlight current treatments in diseases affecting CMs.
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Affiliation(s)
- Josep Julve
- Institut de Recerca de l'HSCSP - Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain.
| | - Jesús M Martín-Campos
- Institut de Recerca de l'HSCSP - Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain.
| | - Joan Carles Escolà-Gil
- Institut de Recerca de l'HSCSP - Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain
| | - Francisco Blanco-Vaca
- Institut de Recerca de l'HSCSP - Institut d'Investigacions Biomèdiques (IIB) Sant Pau, Barcelona, Spain; Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Barcelona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain; Hospital de la Santa Creu i Sant Pau, Servei de Bioquímica, Barcelona, Spain
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Lima-Martínez MM, Piñango M, Lima-Ostos M. Primary hyperchylomicronemia syndrome treated with ciprofibrate in childhood. ENDOCRINOLOGIA Y NUTRICION : ORGANO DE LA SOCIEDAD ESPANOLA DE ENDOCRINOLOGIA Y NUTRICION 2016; 63:98-99. [PMID: 26704984 DOI: 10.1016/j.endonu.2015.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Revised: 10/21/2015] [Accepted: 10/30/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Marcos M Lima-Martínez
- Departamento de Ciencias Fisiológicas, Escuela de Ciencias de la Salud, Universidad de Oriente, Ciudad Bolívar, Venezuela; Unidad de Endocrinología, Diabetes, Metabolismo y Nutrición, Anexo A, Centro Médico Orinoco, Ciudad Bolívar, Venezuela.
| | - Martha Piñango
- Departamento de Ciencias Fisiológicas, Escuela de Ciencias de la Salud, Universidad de Oriente, Ciudad Bolívar, Venezuela
| | - Miguel Lima-Ostos
- Departamento de Ciencias Fisiológicas, Escuela de Ciencias de la Salud, Universidad de Oriente, Ciudad Bolívar, Venezuela; Consultorio Dermatológico «Lima-Ostos», Ciudad Bolívar, Venezuela
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132
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Update on the molecular biology of dyslipidemias. Clin Chim Acta 2016; 454:143-85. [DOI: 10.1016/j.cca.2015.10.033] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/24/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
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Jiang J, Wang Y, Ling Y, Kayoumu A, Liu G, Gao X. A novel APOC2 gene mutation identified in a Chinese patient with severe hypertriglyceridemia and recurrent pancreatitis. Lipids Health Dis 2016; 15:12. [PMID: 26772541 PMCID: PMC4715280 DOI: 10.1186/s12944-015-0171-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 12/29/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The severe forms of hypertriglyceridemia are usually caused by genetic defects. In this study, we described a Chinese female with severe hypertriglyceridemia caused by a novel homozygous mutation in the APOC2 gene. METHODS Lipid profiles of the pedigree were studied in detail. LPL and HL activity were also measured. The coding regions of 5 candidate genes (namely LPL, APOC2, APOA5, LMF1, and GPIHBP1) were sequenced using genomic DNA from peripheral leucocytes. The ApoE gene was also genotyped. RESULTS Serum triglyceride level was extremely high in the proband, compared with other family members. Plasma LPL activity was also significantly reduced in the proband. Serum ApoCII was very low in the proband as well as in the heterozygous mutation carriers. A novel mutation (c.86A > CC) was identified on exon 3 [corrected] of the APOC2 gene, which converted the Asp [corrected] codon at position 29 into Ala, followed by a termination codon (TGA). CONCLUSIONS This study presented the first case of ApoCII deficiency in the Chinese population, with a novel mutation c.86A > CC in the APOC2 gene identified. Serum ApoCII protein might be a useful screening test for identifying mutation carriers.
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Affiliation(s)
- Jingjing Jiang
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Yuhui Wang
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Yan Ling
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Abudurexiti Kayoumu
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - George Liu
- Institute of Cardiovascular Science, Peking University and Key laborotory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China
| | - Xin Gao
- Department of Endocrinology and Metabolism, Zhongshan Hospital, Fudan University, Shanghai, China.
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134
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Mysling S, Kristensen KK, Larsson M, Beigneux AP, Gårdsvoll H, Fong LG, Bensadouen A, Jørgensen TJ, Young SG, Ploug M. The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain. eLife 2016; 5:e12095. [PMID: 26725083 PMCID: PMC4755760 DOI: 10.7554/elife.12095] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/02/2016] [Indexed: 12/19/2022] Open
Abstract
GPIHBP1 is a glycolipid-anchored membrane protein of capillary endothelial cells that binds lipoprotein lipase (LPL) within the interstitial space and shuttles it to the capillary lumen. The LPL•GPIHBP1 complex is responsible for margination of triglyceride-rich lipoproteins along capillaries and their lipolytic processing. The current work conceptualizes a model for the GPIHBP1•LPL interaction based on biophysical measurements with hydrogen-deuterium exchange/mass spectrometry, surface plasmon resonance, and zero-length cross-linking. According to this model, GPIHBP1 comprises two functionally distinct domains: (1) an intrinsically disordered acidic N-terminal domain; and (2) a folded C-terminal domain that tethers GPIHBP1 to the cell membrane by glycosylphosphatidylinositol. We demonstrate that these domains serve different roles in regulating the kinetics of LPL binding. Importantly, the acidic domain stabilizes LPL catalytic activity by mitigating the global unfolding of LPL's catalytic domain. This study provides a conceptual framework for understanding intravascular lipolysis and GPIHBP1 and LPL mutations causing familial chylomicronemia. DOI:http://dx.doi.org/10.7554/eLife.12095.001 Fat is an important part of our diet. The intestines absorb fats and package them into particles called lipoproteins. After reaching the bloodstream, the fat molecules (lipids) in the lipoproteins are broken down by an enzyme called lipoprotein lipase (LPL), which is located along the surface of small blood vessels. This releases nutrients that can be used by vital tissues – mainly the heart, skeletal muscle, and adipose tissues. LPL is produced by muscle and adipose tissue, but it is quickly swept up by a protein called GPIHBP1 and shuttled to its site of action inside the blood vessels. Mutations that alter the structure of LPL or GPIHBP1 can prevent the breakdown of lipids, resulting in high levels of lipids in the blood. This can lead to inflammation in the pancreas and also increases the risk of heart attacks and strokes. Many earlier studies have examined the properties of LPL, but our understanding of GPIHBP1 has been limited, mainly because it has been difficult to purify GPIHBP1 for analysis. Using genetically altered insect cells, Mysling et al. were able to purify two different forms of GPIHBP1 – a full-length version and a shorter version that lacked a small section at the end of the molecule known as the acidic domain. This revealed that the opposite end of the molecule – called the carboxyl-terminal domain – is primarily responsible for binding LPL and anchoring it inside blood vessels. Once LPL is bound to GPIHBP1, the acidic domain of GPIHBP1 helps to stabilize LPL. If GPIHBP1’s acidic domain is missing then LPL is more susceptible to losing its structure, rendering it incapable of breaking down the lipids in the blood. Mysling et al. describe a new model for how LPL and GPIHBP1 interact that explains how specific mutations in the genes that encode these proteins interfere with the delivery of LPL to small blood vessels. In the future, this could help researchers to develop new strategies to treat people with high levels of lipids in their blood. DOI:http://dx.doi.org/10.7554/eLife.12095.002
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Affiliation(s)
- Simon Mysling
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark.,Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Kristian Kølby Kristensen
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Mikael Larsson
- Department of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Anne P Beigneux
- Department of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Henrik Gårdsvoll
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - André Bensadouen
- Division of Nutritional Science, Cornell University, Ithaca, United States
| | - Thomas Jd Jørgensen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Human Genetics, University of California, Los Angeles, Los Angeles, United States
| | - Michael Ploug
- Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark.,Biotech Research and Innovation Centre, University of Copenhagen, Copenhagen, Denmark
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135
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Rodrigues R, Artieda M, Tejedor D, Martínez A, Konstantinova P, Petry H, Meyer C, Corzo D, Sundgreen C, Klor HU, Gouni-Berthold I, Westphal S, Steinhagen-Thiessen E, Julius U, Winkler K, Stroes E, Vogt A, Hardt P, Prophet H, Otte B, Nordestgaard BG, Deeb SS, Brunzell JD. Pathogenic classification of LPL gene variants reported to be associated with LPL deficiency. J Clin Lipidol 2015; 10:394-409. [PMID: 27055971 DOI: 10.1016/j.jacl.2015.12.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 12/21/2015] [Indexed: 01/01/2023]
Abstract
BACKGROUND Lipoprotein lipase (LPL) deficiency is a serious lipid disorder of severe hypertriglyceridemia (SHTG) with chylomicronemia. A large number of variants in the LPL gene have been reported but their influence on LPL activity and SHTG has not been completely analyzed. Gaining insight into the deleterious effect of the mutations is clinically essential. METHODS We used gene sequencing followed by in-vivo/in-vitro and in-silico tools for classification. We classified 125 rare LPL mutations in 33 subjects thought to have LPL deficiency and in 314 subjects selected for very SHTG. RESULTS Of the 33 patients thought to have LPL deficiency, only 13 were homozygous or compound heterozygous for deleterious mutations in the LPL gene. Among the 314 very SHTG patients, 3 were compound heterozygous for pathogenic mutants. In a third group of 51,467 subjects, from a general population, carriers of common variants, Asp9Asn and Asn291Ser, were associated with mild increase in triglyceride levels (11%-35%). CONCLUSION In total, 39% of patients clinically diagnosed as LPL deficient had 2 deleterious variants. Three patients selected for very SHTG had LPL deficiency. The deleterious mutations associated with LPL deficiency will assist in the diagnosis and selection of patients as candidates for the presently approved LPL gene therapy.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Hans U Klor
- Director of the German HITRIG, Third Medical Department and Policlinic, Giessen University Hospital, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Ioanna Gouni-Berthold
- Center for Endocrinology, Diabetes and Preventive Medicine, University of Cologne, Cologne, Germany
| | - Sabine Westphal
- Institute of Clinical Chemistry, Lipid Clinic, Magdeburg, Germany
| | | | - Ulrich Julius
- Universitätsklinikum Carl Gustav Carus an der Technischen Universität, Medizinische Klinik III, Dresden, Germany
| | - Karl Winkler
- Institute of Clinical Chemistry and Laboratory Medicine and Lipid Outpatient Clinic, University Hospital Freiburg, Freiburg, Germany
| | - Erik Stroes
- Department of Vascular Medicine, Amsterdam Medical Center/University of Amsterdam, Amsterdam, The Netherlands
| | - Anja Vogt
- LMU Klinikum der Universität München, Medizinische Klinik und Poliklinik 4, München, Germany
| | - Phillip Hardt
- Gießen and Marburg University Hospital, Giessen, Germany
| | | | - Britta Otte
- Universitätsklinikum Münster, Medizinische Klinik D, Med. Clinic, Münster, Münster, Germany
| | - Borge G Nordestgaard
- Department of Clinical Biochemistry, Herlev Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Copenhagen General Population Study, Herlev Hospital, Copenhagen University Hospital, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Samir S Deeb
- Department of Medicine (Division of Medical Genetics), University of Washington, Seattle, WA, USA; Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - John D Brunzell
- Department of Medicine (Division of Metabolism, Endocrinology and Nutrition), University of Washington, Seattle, WA, USA
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Wagner T, Bartelt A, Schlein C, Heeren J. Genetic Dissection of Tissue-Specific Apolipoprotein E Function for Hypercholesterolemia and Diet-Induced Obesity. PLoS One 2015; 10:e0145102. [PMID: 26695075 PMCID: PMC4687855 DOI: 10.1371/journal.pone.0145102] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/27/2015] [Indexed: 12/11/2022] Open
Abstract
ApoE deficiency in mice (Apoe−/−) results in severe hypercholesterolemia and atherosclerosis. In diet-induced obesity, Apoe−/− display steatohepatitis but reduced accumulation of triacylglycerides and enhanced insulin sensitivity in white adipose tissue (WAT). Although the vast majority of apoE is expressed by hepatocytes apoE is also abundantly expressed in WAT. As liver and adipose tissue play important roles for metabolism, this study aims to outline functions of both hepatocyte- and adipocyte-derived apoE separately by investigating a novel mouse model of tissue-specific apoE deficiency. Therefore we generated transgenic mice carrying homozygous floxed Apoe alleles. Mice lacking apoE either in hepatocytes (ApoeΔHep) or in adipose tissue (ApoeΔAT) were fed experimental diets. ApoeΔHep exhibited slightly higher body weights, adiposity and liver weights on diabetogenic high fat diet (HFD). Accordingly, hepatic steatosis and markers of inflammation were more pronounced compared to controls. Hypercholesterolemia evoked by lipoprotein remnant accumulation was present in ApoeΔHep mice fed a Western type diet (WTD). Lipidation of VLDL particles and tissue uptake of VLDL were disturbed in ApoeΔHep while the plasma clearance rate remained unaltered. ApoeΔAT did not display any detectable phenotype, neither on HFD nor on WTD. In conclusion, our novel conditional apoE deletion model has proven here the role of hepatocyte apoE for VLDL production and diet-induced dyslipidemia. Specific deletion of apoE in adipocytes cannot reproduce the adipose phenotype of global Apoe−/− mice, suggesting that apoE produced in other cell types than hepatocytes or adipocytes explains the lean and insulin-sensitive phenotype described for Apoe−/− mice.
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Affiliation(s)
- Tobias Wagner
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Alexander Bartelt
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Schlein
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Joerg Heeren
- Department of Biochemistry and Molecular Cell Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
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Khovidhunkit W, Charoen S, Kiateprungvej A, Chartyingcharoen P, Muanpetch S, Plengpanich W. Rare and common variants in LPL and APOA5 in Thai subjects with severe hypertriglyceridemia: A resequencing approach. J Clin Lipidol 2015; 10:505-511.e1. [PMID: 27206937 DOI: 10.1016/j.jacl.2015.11.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 10/29/2015] [Accepted: 11/01/2015] [Indexed: 12/01/2022]
Abstract
BACKGROUND Severe hypertriglyceridemia usually results from a combination of genetic and environmental factors. Few data exist on the genetics of severe hypertriglyceridemia in Asian populations. OBJECTIVE To examine the genetic variants of 3 candidate genes known to influence triglyceride metabolism, LPL, APOC2, and APOA5, which encode lipoprotein lipase, apolipoprotein C-II, and apolipoprotein A-V, respectively, in a large group of Thai subjects with severe hypertriglyceridemia. METHODS We identified sequence variants of LPL, APOC2, and APOA5 by sequencing exons and exon-intron junctions in 101 subjects with triglyceride levels ≥ 10 mmol/L (886 mg/dL) and compared with those of 111 normotriglyceridemic subjects. RESULTS Six different rare variants in LPL were found in 13 patients, 2 of which were novel (1 heterozygous missense variant: p.Arg270Gly and 1 frameshift variant: p.Asp308Glyfs*3). Four previously identified heterozygous missense variants in LPL were p.Ala98Thr, p.Leu279Val, p.Leu279Arg, and p.Arg432Thr. Collectively, these rare variants were found only in the hypertriglyceridemic group but not in the control group (13% vs 0%, P < .0001). One common variant in APOA5 (p.Gly185Cys, rs2075291) was found at a higher frequency in the hypertriglyceridemic group compared with the control group (25% vs 6%, respectively, P < .0005). Altogether, rare variants in LPL or APOA5 and/or the common APOA5 p.Gly185Cys variant were found in 37% of the hypertriglyceridemic group vs 6% in the controls (P = 3.1 × 10(-8)). No rare variant in APOC2 was identified. CONCLUSIONS Rare variants in LPL and a common variant in APOA5 were more commonly found in Thai subjects with severe hypertriglyceridemia. A common p.Gly185Cys APOA5 variant, in particular, was quite prevalent and potentially contributed to hypertriglyceridemia in this group of patients.
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Affiliation(s)
- Weerapan Khovidhunkit
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Department of Medicine, Excellence Center for Diabetes, Hormone, and Metabolism, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
| | - Supannika Charoen
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Arunrat Kiateprungvej
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand
| | - Palm Chartyingcharoen
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Department of Medicine, Excellence Center for Diabetes, Hormone, and Metabolism, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Suwanna Muanpetch
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Department of Medicine, Excellence Center for Diabetes, Hormone, and Metabolism, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
| | - Wanee Plengpanich
- Hormonal and Metabolic Disorders Research Unit, Division of Endocrinology and Metabolism, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand; Department of Medicine, Excellence Center for Diabetes, Hormone, and Metabolism, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand
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138
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A Chinese patient with recurrent pancreatitis during pregnancy induced by hypertriglyceridemia associated with compound heterozygosity (Glu242Lys and Leu252VaL) in the lipoprotein lipase gene. J Clin Lipidol 2015; 10:199-203.e1. [PMID: 26892137 DOI: 10.1016/j.jacl.2015.09.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 09/05/2015] [Accepted: 09/16/2015] [Indexed: 11/21/2022]
Abstract
We herein report a novel compound heterozygote of Glu242Lys and Leu252Val in a Chinese patient, characterized by recurrent hypertriglyceridemia-induced acute pancreatitis caused by lipoprotein lipase deficiency. The proband's LPL level after injection of heparin was measured at 184 U/L, considerably lower than the normal controls (382 U/L). Furthermore, LPL activity in the proband was 16.7% of the normal controls. However, the hepatic lipase activity was 80% of the normal controls. These results indicated that the compound mutation was associated with hypertriglyceridemia due to both LPL deficiency and defective LPL function. The LPL deficiency was partially compensated by the roughly normal hepatic lipase, resulting in the apparent normal phenotype of the proband until pregnancy.
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Ariza MJ, Martínez-Hernández PL, Ibarretxe D, Rabacchi C, Rioja J, Grande-Aragón C, Plana N, Tarugi P, Olivecrona G, Calandra S, Valdivielso P. Novel mutations in the GPIHBP1 gene identified in 2 patients with recurrent acute pancreatitis. J Clin Lipidol 2015; 10:92-100.e1. [PMID: 26892125 DOI: 10.1016/j.jacl.2015.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 09/09/2015] [Accepted: 09/16/2015] [Indexed: 11/16/2022]
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.
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Affiliation(s)
- María José Ariza
- Department of Medicine and Dermatology, Lipids and Atherosclerosis Laboratory, CIMES, University of Málaga, Málaga, Spain.
| | | | - Daiana Ibarretxe
- Vascular Medicine and Metabolism Unit, Research Unit on Lipids and Atherosclerosis, Sant Joan University Hospital, Universitat Rovira i Virgili, IISPV, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Reus, Spain
| | - Claudio Rabacchi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - José Rioja
- Department of Medicine and Dermatology, Lipids and Atherosclerosis Laboratory, CIMES, University of Málaga, Málaga, Spain
| | | | - Nuria Plana
- Vascular Medicine and Metabolism Unit, Research Unit on Lipids and Atherosclerosis, Sant Joan University Hospital, Universitat Rovira i Virgili, IISPV, Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Disorders (CIBERDEM), Reus, Spain
| | - Patrizia Tarugi
- Department of Life Sciences, University of Modena & Reggio Emilia, Modena, Italy
| | - Gunilla Olivecrona
- Department of Medical Biosciences, Physiological Chemistry, Umeå University, Umeå, Sweden
| | - Sebastiano Calandra
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena & Reggio Emilia Modena, Italy
| | - Pedro Valdivielso
- Department of Medicine and Dermatology, Lipids and Atherosclerosis Laboratory, CIMES, University of Málaga, Málaga, Spain; Internal Medicine Unit, Virgen de la Victoria University Hospital, Málaga, Spain
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Valdivielso P. [Hypertriglyceridemia and LMF 1: Another piece of the puzzle]. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ARTERIOSCLEROSIS 2015; 27:253-255. [PMID: 26398545 DOI: 10.1016/j.arteri.2015.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 08/06/2015] [Indexed: 06/05/2023]
Affiliation(s)
- Pedro Valdivielso
- Unidad de Lípidos, Hospital Virgen de la Victoria,, Málaga, España; Departamento de Medicina y Dermatología, Instituto de Biomedicina de Málaga (IBIMA), Universidad de Málaga, Málaga, España.
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Lamiquiz-Moneo I, Bea AM, Mateo-Gallego R, Baila-Rueda L, Cenarro A, Pocoví M, Civeira F, de Castro-Orós I. [Identification of variants in LMF1 gene associated with primary hypertriglyceridemia]. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ARTERIOSCLEROSIS 2015; 27:246-252. [PMID: 25817768 DOI: 10.1016/j.arteri.2015.02.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/05/2015] [Accepted: 02/06/2015] [Indexed: 06/04/2023]
Abstract
The majority of severe primary hypertriglyceridemia (HTG) are diagnosed in adults, and their molecular bases have not yet been fully defined. The promoter, coding regions and intron-exon boundaries of LMF1 were sequenced in 112 patients with severe primary hipertrigliceridemia (defined as TG above 500mg/dl). Five patients (4.46%) were carriers of four rare variants in the LMF1 gene associated with HTG, which participate in lipoprotein lipase (LpL) function. Also, we have identified two common variants, c.194-28 T>G and c.729+18C>G that were associated with HTG, with a different allelic frequency to that observed in the general population. A bioinformatic analysis of all found variants was conducted, defining the following as potentially harmful: p.Arg364Gln, p.Arg451Trp, p.Pro562Arg and p.Leu85Leu. Our results suggest that LMF1 mutations are involved in a substantial proportion of cases with severe HTG, putting together the moderate-aggressive effect of rare mutations with polymorphisms classically associated with this disease.
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Affiliation(s)
- Itziar Lamiquiz-Moneo
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España.
| | - Ana M Bea
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Rocío Mateo-Gallego
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Lucía Baila-Rueda
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Ana Cenarro
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Miguel Pocoví
- Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Fernando Civeira
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
| | - Isabel de Castro-Orós
- Unidad Clínica y de Investigación en Lípidos y Arteriosclerosis, Hospital Universitario Miguel Servet, Instituto de Investigación Sanitaria Aragón, Zaragoza, España
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Rabacchi C, Pisciotta L, Cefalù AB, Noto D, Fresa R, Tarugi P, Averna M, Bertolini S, Calandra S. Spectrum of mutations of the LPL gene identified in Italy in patients with severe hypertriglyceridemia. Atherosclerosis 2015; 241:79-86. [DOI: 10.1016/j.atherosclerosis.2015.04.815] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 04/24/2015] [Accepted: 04/26/2015] [Indexed: 12/20/2022]
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Abdullah MMH, Jones PJH, Eck PK. Nutrigenetics of cholesterol metabolism: observational and dietary intervention studies in the postgenomic era. Nutr Rev 2015; 73:523-43. [PMID: 26117841 DOI: 10.1093/nutrit/nuv016] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cholesterol metabolism is a well-defined responder to dietary intakes and a classic biomarker of cardiovascular health. For this reason, circulating cholesterol levels have become key in shaping nutritional recommendations by health authorities worldwide for better management of cardiovascular disease, a leading cause of mortality and one of the most costly health problems globally. Data from observational and dietary intervention studies, however, highlight a marked between-individual variability in the response of cholesterol metabolism to similar dietary protocols, a phenomenon linked to genetic heterogeneity. This review summarizes the postgenomic evidence of polymorphisms within cholesterol-associated genes relative to fasting circulating cholesterol levels under diverse nutritional conditions. A number of cholesterol-related gene-diet interactions are confirmed, which may have clinical importance, supporting a deeper look into the rapidly emerging field of nutrigenetics for meaningful conclusions that may eventually lead to genetically targeted dietary recommendations in the era of personalized nutrition.
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Affiliation(s)
- Mohammad M H Abdullah
- M.M.H. Abdullah, P.J.H. Jones, and P.K. Eck are with the Department of Human Nutritional Sciences and the Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, Winnipeg, Manitoba, Canada. P.J.H. Jones is with the Department of Food Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Peter J H Jones
- M.M.H. Abdullah, P.J.H. Jones, and P.K. Eck are with the Department of Human Nutritional Sciences and the Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, Winnipeg, Manitoba, Canada. P.J.H. Jones is with the Department of Food Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Peter K Eck
- M.M.H. Abdullah, P.J.H. Jones, and P.K. Eck are with the Department of Human Nutritional Sciences and the Richardson Centre for Functional Foods and Nutraceuticals (RCFFN), University of Manitoba, Winnipeg, Manitoba, Canada. P.J.H. Jones is with the Department of Food Science, University of Manitoba, Winnipeg, Manitoba, Canada.
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Xie SL, Chen TZ, Huang XL, Chen C, Jin R, Huang ZM, Zhou MT. Genetic Variants Associated with Gestational Hypertriglyceridemia and Pancreatitis. PLoS One 2015; 10:e0129488. [PMID: 26079787 PMCID: PMC4469420 DOI: 10.1371/journal.pone.0129488] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 05/08/2015] [Indexed: 11/18/2022] Open
Abstract
Severe hypertriglyceridemia is a well-known cause of pancreatitis. Usually, there is a moderate increase in plasma triglyceride level during pregnancy. Additionally, certain pre-existing genetic traits may render a pregnant woman susceptible to development of severe hypertriglyceridemia and pancreatitis, especially in the third trimester. To elucidate the underlying mechanism of gestational hypertriglyceridemic pancreatitis, we undertook DNA mutation analysis of the lipoprotein lipase (LPL), apolipoprotein C2 (APOC2), apolipoprotein A5 (APOA5), lipase maturation factor 1 (LMF1), and glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) genes in five unrelated pregnant Chinese women with severe hypertriglyceridemia and pancreatitis. DNA sequencing showed that three out of five patients had the same homozygous variation, p.G185C, in APOA5 gene. One patient had a compound heterozygous mutation, p.A98T and p.L279V, in LPL gene. Another patient had a compound heterozygous mutation, p.A98T & p.C14F in LPL and GPIHBP1 gene, respectively. No mutations were seen in APOC2 or LMF1 genes. All patients were diagnosed with partial LPL deficiency in non-pregnant state. As revealed in our study, genetic variants appear to play an important role in the development of severe gestational hypertriglyceridemia, and, p.G185C mutation in APOA5 gene appears to be the most common variant implicated in the Chinese population. Antenatal screening for mutations in susceptible women, combined with subsequent interventions may be invaluable in the prevention of potentially life threatening gestational hypertriglyceridemia-induced pancreatitis.
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Affiliation(s)
- Sai-Li Xie
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Tan-Zhou Chen
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xie-Lin Huang
- Ren-Ji Study, Wenzhou Medical University, Wenzhou, China
| | - Chao Chen
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Rong Jin
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Zhi-Ming Huang
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
- * E-mail: (M-TZ); (Z-MH)
| | - Meng-Tao Zhou
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
- * E-mail: (M-TZ); (Z-MH)
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Liu C, Gates KP, Fang L, Amar MJ, Schneider DA, Geng H, Huang W, Kim J, Pattison J, Zhang J, Witztum JL, Remaley AT, Dong PD, Miller YI. Apoc2 loss-of-function zebrafish mutant as a genetic model of hyperlipidemia. Dis Model Mech 2015; 8:989-98. [PMID: 26044956 PMCID: PMC4527288 DOI: 10.1242/dmm.019836] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 05/29/2015] [Indexed: 12/27/2022] Open
Abstract
Apolipoprotein C-II (APOC2) is an obligatory activator of lipoprotein lipase. Human patients with APOC2 deficiency display severe hypertriglyceridemia while consuming a normal diet, often manifesting xanthomas, lipemia retinalis and pancreatitis. Hypertriglyceridemia is also an important risk factor for development of cardiovascular disease. Animal models to study hypertriglyceridemia are limited, with no Apoc2-knockout mouse reported. To develop a genetic model of hypertriglyceridemia, we generated an apoc2 mutant zebrafish characterized by the loss of Apoc2 function. apoc2 mutants show decreased plasma lipase activity and display chylomicronemia and severe hypertriglyceridemia, which closely resemble the phenotype observed in human patients with APOC2 deficiency. The hypertriglyceridemia in apoc2 mutants is rescued by injection of plasma from wild-type zebrafish or by injection of a human APOC2 mimetic peptide. Consistent with a previous report of a transient apoc2 knockdown, apoc2 mutant larvae have a minor delay in yolk consumption and angiogenesis. Furthermore, apoc2 mutants fed a normal diet accumulate lipid and lipid-laden macrophages in the vasculature, which resemble early events in the development of human atherosclerotic lesions. In addition, apoc2 mutant embryos show ectopic overgrowth of pancreas. Taken together, our data suggest that the apoc2 mutant zebrafish is a robust and versatile animal model to study hypertriglyceridemia and the mechanisms involved in the pathogenesis of associated human diseases. Highlighted Article: Apoc2 loss-of-function zebrafish display severe hypertriglyceridemia, which is characteristic of human patients with defective lipoprotein lipase activity.
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Affiliation(s)
- Chao Liu
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Keith P Gates
- Sanford Children's Health Research Center, Programs in Genetic Disease and Development and Aging, and Stem Cell and Regenerative Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Longhou Fang
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Marcelo J Amar
- Lipoprotein Metabolism Section, Cardiopulmonary Branch, NHLBI, NIH, Bethesda, MD, USA
| | - Dina A Schneider
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Honglian Geng
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Wei Huang
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jungsu Kim
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jennifer Pattison
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jian Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Joseph L Witztum
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Alan T Remaley
- Lipoprotein Metabolism Section, Cardiopulmonary Branch, NHLBI, NIH, Bethesda, MD, USA
| | - P Duc Dong
- Sanford Children's Health Research Center, Programs in Genetic Disease and Development and Aging, and Stem Cell and Regenerative Biology, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Yury I Miller
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
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A rare variant in MCF2L identified using exclusion linkage in a pedigree with premature atherosclerosis. Eur J Hum Genet 2015; 24:86-91. [PMID: 25898923 DOI: 10.1038/ejhg.2015.70] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 02/27/2015] [Accepted: 03/10/2015] [Indexed: 11/08/2022] Open
Abstract
Cardiovascular disease (CVD) is a major cause of death in Western societies. CVD risk is largely genetically determined. The molecular pathology is, however, not elucidated in a large number of families suffering from CVD. We applied exclusion linkage analysis and next-generation sequencing to elucidate the molecular defect underlying premature CVD in a small pedigree, comprising two generations of which six members suffered from premature CVD. A total of three variants showed co-segregation with the disease status in the family. Two of these variants were excluded from further analysis based on the prevalence in replication cohorts, whereas a non-synonymous variant in MCF.2 Cell Line Derived Transforming Sequence-like protein (MCF2L, c.2066A>G; p.(Asp689Gly); NM_001112732.1), located in the DH domain, was only present in the studied family. MCF2L is a guanine exchange factor that potentially links pathways that signal through Rac1 and RhoA. Indeed, in HeLa cells, MCF2L689Gly failed to activate Rac1 as well as RhoA, resulting in impaired stress fiber formation. Moreover, MCF2L protein was found in human atherosclerotic lesions but not in healthy tissue segments. In conclusion, a rare functional variant in MCF2L, leading to impaired DH function, was identified in a small pedigree with premature CVD. The presence of MCF2L in human atherosclerotic plaque specimen lends further support to its potential role in atherosclerosis.
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147
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Effect of the DGAT1 inhibitor pradigastat on triglyceride and apoB48 levels in patients with familial chylomicronemia syndrome. Lipids Health Dis 2015; 14:8. [PMID: 25889044 PMCID: PMC4337059 DOI: 10.1186/s12944-015-0006-5] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/28/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Familial chylomicronemia syndrome (FCS) is a rare lipid disease caused by complete lipoprotein lipase (LPL) deficiency resulting in fasting chylomicronemia and severe hypertriglyceridemia. Inhibition of diacylglycerol acyltransferase 1 (DGAT1), which mediates chylomicron triglyceride (TG) synthesis, is an attractive strategy to reduce TG levels in FCS. In this study we assessed the safety, tolerability and TG-lowering efficacy of the DGAT1 inhibitor pradigastat in patients with FCS. METHODS Six FCS patients were enrolled in an open-label clinical study. Following a 1-week very low fat diet run-in period patients underwent baseline lipid assessments, including a low fat meal tolerance test. Patients then underwent three consecutive 21 day treatment periods (pradigastat at 20, 40 & 10 mg, respectively). Treatment periods were separated by washout periods of ≥4 weeks. Fasting TG levels were assessed weekly through the treatment periods. Postprandial TGs, ApoB48 and lipoprotein lipid content were also monitored. RESULTS Following once daily oral dosing, steady-state exposure was reached by Day 14. There was an approximately dose proportional increase in pradigastat exposure at studied doses. Pradigastat was associated with a 41% (20 mg) and 70% (40 mg) reduction in fasting triglyceride over 21 days of treatment. The reduction in fasting TG was almost entirely accounted for by a reduction in chylomicron TG. Pradigastat treatment also led to substantial reductions in postprandial TG as well as apo48 (both fasting and postprandial). Pradigastat was safe and well tolerated, with only mild, transient gastrointestinal adverse events. CONCLUSION The novel DGAT1 inhibitor pradigastat substantially reduces plasma TG levels in FCS patients, and may be a promising new treatment for this orphan disease. TRIAL REGISTRATION ClinicalTrials.gov identifier NCT01146522 .
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Abstract
Hypertriglyceridemia (HTG) is a highly prevalent condition that is associated with increased cardiovascular disease risk. HTG may arise as a result of defective metabolism of triglyceride-rich lipoproteins and their remnants, ie, impaired clearance, or increased production, or both. Current categorization of HTG segregates primary and secondary cases, implying genetic and nongenetic causes for each category. Many common and rare variants of the genes encoding factors involved in these pathways have been identified. Although monogenic forms of HTG do occur, most cases are polygenic and often coexist with nongenetic conditions. Cumulative, multiple genetic variants can increase the risks for HTG, whereas environmental and lifestyle factors can force expression of a dyslipidemic phenotype in a genetically susceptible person. HTG states are therefore best viewed as a complex phenotype resulting from the interaction of cumulated multiple susceptibility genes and environmental stressors. In view of the heterogeneity of the HTG states, the absence of a unifying metabolic or genetic abnormality, overlap with the metabolic syndrome and other features of insulin resistance, and evidence in some patients that accumulation of numerous small-effect genetic variants determines whether an individual is susceptible to HTG only or to HTG plus elevated low-density lipoprotein cholesterol, we propose that the diagnosis of primary HTG and further delineation of familial combined hyperlipidemia from familial HTG is neither feasible nor clinically relevant at the present time. The hope is that with greater understanding of genetic and environmental causes and their interaction, therapy can be intelligently targeted in the future.
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Affiliation(s)
- Gary F Lewis
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre (G.F.L., C.X.), University of Toronto, Toronto, Ontario, Canada M5G 2C4; and Robarts Research Institute (R.A.H.), Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada N6A 5B7
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Severe hypertriglyceridemia in a patient heterozygous for a lipoprotein lipase gene allele with two novel missense variants. Eur J Hum Genet 2015; 23:1259-61. [PMID: 25585702 PMCID: PMC4538214 DOI: 10.1038/ejhg.2014.295] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 11/22/2014] [Accepted: 12/12/2014] [Indexed: 12/11/2022] Open
Abstract
Rare monogenic hyperchylomicronemia is caused by loss-of-function mutations in genes involved in the catabolism of triglyceride-rich lipoproteins, including the lipoprotein lipase gene, LPL. Clinical hallmarks of this condition are eruptive xanthomas, recurrent pancreatitis and abdominal pain. Patients with LPL deficiency and severe or recurrent pancreatitis are eligible for the first gene therapy treatment approved by the European Union. Therefore the precise molecular diagnosis of familial hyperchylomicronemia may affect treatment decisions. We present a 57-year-old male patient with excessive hypertriglyceridemia despite intensive lipid-lowering therapy. Abdominal sonography showed signs of chronic pancreatitis. Direct DNA sequencing and cloning revealed two novel missense variants, c.1302A>T and c.1306G>A, in exon 8 of the LPL gene coexisting on the same allele. The variants result in the amino-acid exchanges p.(Lys434Asn) and p.(Gly436Arg). They are located in the carboxy-terminal domain of lipoprotein lipase that interacts with the glycosylphosphatidylinositol-anchored HDL-binding protein (GPIHBP1) and are likely of functional relevance. No further relevant mutations were found by direct sequencing of the genes for APOA5, APOC2, LMF1 and GPIHBP1. We conclude that heterozygosity for damaging mutations of LPL may be sufficient to produce severe hypertriglyceridemia and that chylomicronemia may be transmitted in a dominant manner, at least in some families.
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150
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Chiou KR, Chen CY, Charng MJ. Genetic Diagnosis via Whole Exome Sequencing in Taiwanese Patients with Hypertriglyceridemia. J Atheroscler Thromb 2015; 22:887-900. [DOI: 10.5551/jat.29736] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Kuan-Rau Chiou
- Division of Cardiology, Kaohsiung Veterans General Hospital
- School of Medicine, National Yang-Ming University
| | - Chung-Yung Chen
- Department of Bioscience Technology, Chung Yuan Christian University
| | - Min-ji Charng
- School of Medicine, National Yang-Ming University
- Division of Cardiology, Taipei Veterans General Hospital
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