1
|
Wang Z, Yelamanchili D, Liu J, Gotto AM, Rosales C, Gillard BK, Pownall HJ. Serum opacity factor normalizes erythrocyte morphology in Scarb1 -/- mice in an HDL-free cholesterol-dependent way. J Lipid Res 2023; 64:100456. [PMID: 37821077 PMCID: PMC10641538 DOI: 10.1016/j.jlr.2023.100456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/16/2023] [Accepted: 10/05/2023] [Indexed: 10/13/2023] Open
Abstract
Compared with WT mice, HDL receptor-deficient (Scarb1-/-) mice have higher plasma levels of free cholesterol (FC)-rich HDL and exhibit multiple pathologies associated with a high mol% FC in ovaries, platelets, and erythrocytes, which are reversed by lowering HDL. Bacterial serum opacity factor (SOF) catalyzes the opacification of plasma by targeting and quantitatively converting HDL to neo HDL (HDL remnant), a cholesterol ester-rich microemulsion, and lipid-free APOA1. SOF delivery with an adeno-associated virus (AAVSOF) constitutively lowers plasma HDL-FC and reverses female infertility in Scarb1-/- mice in an HDL-dependent way. We tested whether AAVSOF delivery to Scarb1-/- mice will normalize erythrocyte morphology in an HDL-FC-dependent way. We determined erythrocyte morphology and FC content (mol%) in three groups-WT, untreated Scarb1-/- (control), and Scarb1-/- mice receiving AAVSOF-and correlated these with their respective HDL-mol% FC. Plasma-, HDL-, and tissue-lipid compositions were also determined. Plasma- and HDL-mol% FC positively correlated across all groups. Among Scarb1-/- mice, AAVSOF treatment normalized reticulocyte number, erythrocyte morphology, and erythrocyte-mol% FC. Erythrocyte-mol% FC positively correlated with HDL-mol% FC and with both the number of reticulocytes and abnormal erythrocytes. AAVSOF treatment also reduced FC of extravascular tissues to a lesser extent. HDL-FC spontaneously transfers from plasma HDL to cell membranes. AAVSOF treatment lowers erythrocyte-FC and normalizes erythrocyte morphology and lipid composition by reducing HDL-mol% FC.
Collapse
Affiliation(s)
- Ziyi Wang
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Departments of Endocrinology and Xiangya Hospital, Central South University, Changsha, China
| | | | - Jing Liu
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Departments of Endocrinology and Cardiovascular Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Antonio M Gotto
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Corina Rosales
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Baiba K Gillard
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Department of Medicine, Weill Cornell Medicine, New York, NY, USA
| | - Henry J Pownall
- Center for Bioenergetics, Houston Methodist, Houston, TX, USA; Department of Medicine, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
2
|
Wen Y, Chen YQ, Konrad RJ. The Regulation of Triacylglycerol Metabolism and Lipoprotein Lipase Activity. Adv Biol (Weinh) 2022; 6:e2200093. [PMID: 35676229 DOI: 10.1002/adbi.202200093] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/03/2022] [Indexed: 01/28/2023]
Abstract
Triacylglycerol (TG) metabolism is tightly regulated to maintain a pool of TG within circulating lipoproteins that can be hydrolyzed in a tissue-specific manner by lipoprotein lipase (LPL) to enable the delivery of fatty acids to adipose or oxidative tissues as needed. Elevated serum TG concentrations, which result from a deficiency of LPL activity or, more commonly, an imbalance in the regulation of tissue-specific LPL activities, have been associated with an increased risk of atherosclerotic cardiovascular disease through multiple studies. Among the most critical LPL regulators are the angiopoietin-like (ANGPTL) proteins ANGPTL3, ANGPTL4, and ANGPTL8, and a number of different apolipoproteins including apolipoprotein A5 (ApoA5), apolipoprotein C2 (ApoC2), and apolipoprotein C3 (ApoC3). These ANGPTLs and apolipoproteins work together to orchestrate LPL activity and therefore play pivotal roles in TG partitioning, hydrolysis, and utilization. This review summarizes the mechanisms of action, epidemiological findings, and genetic data most relevant to these ANGPTLs and apolipoproteins. The interplay between these important regulators of TG metabolism in both fasted and fed states is highlighted with a holistic view toward understanding key concepts and interactions. Strategies for developing safe and effective therapeutics to reduce circulating TG by selectively targeting these ANGPTLs and apolipoproteins are also discussed.
Collapse
Affiliation(s)
- Yi Wen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Yan Q Chen
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| | - Robert J Konrad
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA
| |
Collapse
|
3
|
Abstract
Mild to moderate hypertriglyceridemia usually results from multiple small-effect variants in genes that control triglyceride metabolism. Hypertriglyceridemia is a critical component of the metabolic syndrome but can also occur secondary to several other conditions or drugs. Hypertriglyceridemia frequently is associated with an increased risk of cardiovascular disease (CVD). Statins are the mainstay of CVD prevention in hypertriglyceridemia, but eicosapentaenoic ethyl esters should be added in very-high-risk individuals. Although fibrates lower triglyceride levels, their role in CVD prevention remains unclear. Familial partial lipodystrophy is another relatively rare cause, although its true incidence is unknown.
Collapse
Affiliation(s)
- Alan Chait
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, 850 Republican, Box 358062, Seattle, WA 98109, USA.
| |
Collapse
|
4
|
Ayoub C, Azar Y, Maddah D, Ghaleb Y, Elbitar S, Abou-Khalil Y, Jambart S, Varret M, Boileau C, El Khoury P, Abifadel M. Low circulating PCSK9 levels in LPL homozygous children with chylomicronemia syndrome in a syrian refugee family in Lebanon. Front Genet 2022; 13:961028. [PMID: 36061186 PMCID: PMC9437297 DOI: 10.3389/fgene.2022.961028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/26/2022] [Indexed: 12/17/2022] Open
Abstract
Familial chylomicronemia syndrome is a rare autosomal recessive disorder of lipoprotein metabolism characterized by the presence of chylomicrons in fasting plasma and an important increase in plasma triglycerides (TG) levels that can exceed 22.58 mmol/l. The disease is associated with recurrent episodes of abdominal pain and pancreatitis, eruptive cutaneous xanthomatosis, lipemia retinalis, and hepatosplenomegaly. A consanguineous Syrian family who migrated to Lebanon was referred to our laboratory after perceiving familial chylomicronemia syndrome in two children. The LPL and PCSK9 genes were sequenced and plasma PCSK9 levels were measured. Sanger sequencing of the LPL gene revealed the presence of the p.(Val227Phe) pathogenic variant in exon 5 at the homozygous state in the two affected children, and at the heterozygous state in the other recruited family members. Interestingly, PCSK9 levels in homozygous carriers of the p.(Val227Phe) were ≈50% lower than those in heterozygous carriers of the variant (p-value = 0.13) and ranged between the 5th and the 7.5th percentile of PCSK9 levels in a sample of Lebanese children of approximately the same age group. Moreover, this is the first reported case of individuals carrying simultaneously an LPL pathogenic variant and PCSK9 variants, the L10 and L11 leucine insertion, which can lower and raise low-density lipoprotein cholesterol (LDL-C) levels respectively. TG levels fluctuated concomitantly between the two children, were especially high following the migration from a country to another, and were reduced under a low-fat diet. This case is crucial to raise public awareness on the risks of consanguineous marriages to decrease the emergence of inherited autosomal recessive diseases. It also highlights the importance of the early diagnosis and management of these diseases to prevent serious complications, such as recurrent pancreatitis in the case of familial hyperchylomicronemia.
Collapse
Affiliation(s)
- Carine Ayoub
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Yara Azar
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Dina Maddah
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Youmna Ghaleb
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Sandy Elbitar
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Yara Abou-Khalil
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Selim Jambart
- Faculty of Medicine, Saint Joseph University of Beirut, Beirut, Lebanon
| | - Mathilde Varret
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Catherine Boileau
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
- Genetic Department, AP-HP, Hôpital Bichat, Paris, France
| | - Petra El Khoury
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
| | - Marianne Abifadel
- Laboratory of Biochemistry and Molecular Therapeutics (LBTM), Faculty of Pharmacy, Pôle Technologie- Santé, Saint Joseph University of Beirut, Beirut, Lebanon
- Laboratory for Vascular Translational Science (LVTS), INSERM, Paris Cité University and Sorbonne Paris Nord University, Paris, France
- *Correspondence: Marianne Abifadel,
| |
Collapse
|
5
|
Chait A, Feingold KR. Approach to patients with hypertriglyceridemia. Best Pract Res Clin Endocrinol Metab 2022; 37:101659. [PMID: 35459627 DOI: 10.1016/j.beem.2022.101659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Elevated triglyceride levels increase the risk of arteriosclerotic cardiovascular disease (ASCVD) and severely elevated triglyceride levels also increase the risk of triglyceride-induced pancreatitis. Although substantially reducing triglyceride levels will prevent pancreatitis, whether lowering triglycerides per se will reduce CVD risk is unclear. In this review, we outline several principles that will help in deciding who and how to treat patients with elevated triglyceride levels in order to prevent both ASCVD and pancreatitis. Using these principles will help in making decisions regarding the treatment of elevated triglyceride levels.
Collapse
Affiliation(s)
- Alan Chait
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, WA, USA.
| | | |
Collapse
|
6
|
Ashraf AP, Sunil B, Bamba V, Breidbart E, Brar PC, Chung S, Gupta A, Khokhar A, Kumar S, Lightbourne M, Kamboj MK, Miller RS, Patni N, Raman V, Shah AS, Wilson DP, Kohn B. Case Studies in Pediatric Lipid Disorders and Their Management. J Clin Endocrinol Metab 2021; 106:3605-3620. [PMID: 34363474 PMCID: PMC8787854 DOI: 10.1210/clinem/dgab568] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT Identification of modifiable risk factors, including genetic and acquired disorders of lipid and lipoprotein metabolism, is increasingly recognized as an opportunity to prevent premature cardiovascular disease (CVD) in at-risk youth. Pediatric endocrinologists are at the forefront of this emerging public health concern and can be instrumental in beginning early interventions to prevent premature CVD-related events during adulthood. AIM In this article, we use informative case presentations to provide practical approaches to the management of pediatric dyslipidemia. CASES We present 3 scenarios that are commonly encountered in clinical practice: isolated elevation of low-density lipoprotein cholesterol (LDL-C), combined dyslipidemia, and severe hypertriglyceridemia. Treatment with statin is indicated when the LDL-C is ≥190 mg/dL (4.9 mmol/L) in children ≥10 years of age. For LDL-C levels between 130 and 189 mg/dL (3.4-4.89 mmol/L) despite dietary and lifestyle changes, the presence of additional risk factors and comorbid conditions would favor statin therapy. In the case of combined dyslipidemia, the primary treatment target is LDL-C ≤130 mg/dL (3.4 mmol/L) and the secondary target non-high-density lipoprotein cholesterol <145 mg/dL (3.7 mmol/L). If the triglyceride is ≥400 mg/dL (4.5 mmol/L), prescription omega-3 fatty acids and fibrates are considered. In the case of triglyceride >1000 mg/dL (11.3 mmol/L), dietary fat restriction remains the cornerstone of therapy, even though the landscape of medications is changing. CONCLUSION Gene variants, acquired conditions, or both are responsible for dyslipidemia during childhood. Extreme elevations of triglycerides can lead to pancreatitis. Early identification and management of dyslipidemia and cardiovascular risk factors is extremely important.
Collapse
Affiliation(s)
| | | | - Vaneeta Bamba
- Department of Pediatrics, Division of Endocrinology, Children’s Hospital of Philadelphia, The Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Emily Breidbart
- Department of Pediatrics, Division Pediatric Endocrinology and Diabetes NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Preneet Cheema Brar
- Department of Pediatrics, Division Pediatric Endocrinology and Diabetes, NYU Langone Medical Center, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Stephanie Chung
- Section on Pediatric Diabetes, Obesity, and Metabolism, National Institutes of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD 20814, USA
| | - Anshu Gupta
- Department of Pediatrics, Children’s Hospital of Richmond at Virginia Commonwealth University, Richmond, VA 23219, USA
| | - Aditi Khokhar
- Department of Pediatrics, Rutgers New Jersey Medical School, NJ 07103, USA
| | - Seema Kumar
- Division of Pediatric Endocrinology, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Marissa Lightbourne
- Pediatric and Adult Endocrinology Faculty, NICHD, National Institutes of Health, Bethesda, MD 20814, USA
| | - Manmohan K Kamboj
- Department of Pediatrics, Nationwide Children’s Hospital, The Ohio State University, Columbus, OH 43205, USA
| | - Ryan S Miller
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD 21093, USA
| | - Nivedita Patni
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Vandana Raman
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84108, USA
| | - Amy S Shah
- Department of Pediatrics, Adolescent Type 2 Diabetes Program, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Don P Wilson
- Cardiovascular Health and Risk Prevention, Pediatric Endocrinology and Diabetes, Cook Children’s Medical Center, Fort Worth, TX 76104, USA
| | - Brenda Kohn
- Correspondence: Brenda Kohn, MD, Division Pediatric Endocrinology, NYU Medical Center, NYU Grossman School of Medicine, 530 1st Ave, New York, NY 10016, USA.
| |
Collapse
|
7
|
Muñiz-Grijalvo O, Diaz-Diaz JL. Familial chylomicronemia and multifactorial chylomicronemia. CLINICA E INVESTIGACION EN ARTERIOSCLEROSIS : PUBLICACION OFICIAL DE LA SOCIEDAD ESPANOLA DE ARTERIOSCLEROSIS 2021; 33 Suppl 2:56-62. [PMID: 34006355 DOI: 10.1016/j.arteri.2021.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 02/17/2021] [Indexed: 11/19/2022]
Abstract
The accumulation of chylomicrons in plasma beyond the postprandial period is a pathological event secondary to the partial or complete lack of activity of lipoprotein lipase that can lead to recurrent episodes of abdominal pain and acute pancreatitis. This article reviews the pathophysiology of this syndrome and the differential characteristics depending on whether it is due to congenital monogenic causes or acquired on a polygenic basis in which multiple factors may inluence.
Collapse
Affiliation(s)
| | - José Luis Diaz-Diaz
- Unidad de Lípidos, Servicio de Medicina interna, Complexo Hospitalario Universitario de A Coruña
| |
Collapse
|
8
|
Wu G, Bockman B, Perez J. Acute Myocardial Infarction Complicated by Very Severe Hypertriglyceridemia. CASE REPORTS IN ACUTE MEDICINE 2020. [DOI: 10.1159/000511065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Hypertriglyceridemia (HTG) is the elevation of serum triglyceride levels above 150 mg/dL and is linked to complications such as pancreatitis and increased mortality risk. An uncommonly known co-presentation of HTG is acute ST-elevation myocardial infarction (STEMI), with the literature citing only one other case of acute STEMI complicated by very severe HTG. We report on a 36-year-old male with multiple comorbidities presenting with acute STEMI and elevated pancreatic enzymes suggestive of pancreatitis. A subsequent lipid profile revealed very severe HTG with a triglyceride level of 2,700 mg/dL. We discuss the pathogenesis, management, and screening guidelines of very severe HTG. Clinicians should be aware that acute STEMI complicated by HTG is rare and that earlier detection and intervention may allow for the prevention of life-threatening complications.
Collapse
|
9
|
Manfredi M, Chiariello C, Conte E, Castagna A, Robotti E, Gosetti F, Patrone M, Martinelli N, Bassi A, Cecconi D, Marengo E, Olivieri O. Plasma Proteome Profiles of Stable CAD Patients Stratified According to Total Apo C‐III Levels. Proteomics Clin Appl 2018; 13:e1800023. [DOI: 10.1002/prca.201800023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/30/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Marcello Manfredi
- Department of Sciences and Technological InnovationUniversity of Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy
- ISALIT S.r.l. Via Canobia 4/6 28100 Novara Italy
| | - Carmela Chiariello
- Department of MedicineUnit of Internal MedicineUniversity of Verona P.le L.A. Scuro 10 37134 Verona Italy
| | | | - Annalisa Castagna
- Department of MedicineUnit of Internal MedicineUniversity of Verona P.le L.A. Scuro 10 37134 Verona Italy
| | - Elisa Robotti
- Department of Sciences and Technological InnovationUniversity of Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy
- ISALIT S.r.l. Via Canobia 4/6 28100 Novara Italy
| | - Fabio Gosetti
- Department of Sciences and Technological InnovationUniversity of Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy
| | - Mauro Patrone
- Department of Sciences and Technological InnovationUniversity of Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy
| | - Nicola Martinelli
- Department of MedicineUnit of Internal MedicineUniversity of Verona P.le L.A. Scuro 10 37134 Verona Italy
| | - Antonella Bassi
- Laboratory of Clinical Chemistry and HematologyUniversity Hospital of Verona P.le L.A. Scuro 10 37134 Verona Italy
| | - Daniela Cecconi
- Department of BiotechnologyProteomics and Mass Spectrometry LaboratoryUniversity of Verona Strada le grazie 15 37134 Verona Italy
| | - Emilio Marengo
- Department of Sciences and Technological InnovationUniversity of Piemonte Orientale Viale T. Michel 11 15121 Alessandria Italy
| | - Oliviero Olivieri
- Department of MedicineUnit of Internal MedicineUniversity of Verona P.le L.A. Scuro 10 37134 Verona Italy
| |
Collapse
|
10
|
Lian J, Bahitham W, Panigrahi R, Nelson R, Li L, Watts R, Thiesen A, Lemieux MJ, Lehner R. Genetic variation in human carboxylesterase CES1 confers resistance to hepatic steatosis. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:688-699. [DOI: 10.1016/j.bbalip.2018.04.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Revised: 02/21/2018] [Accepted: 04/05/2018] [Indexed: 12/12/2022]
|
11
|
Benes LB, Brandt EJ, Davidson MH. Advances in diagnosis and potential therapeutic options for familial chylomicronemia syndrome. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1419863] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Lane B. Benes
- Section of Cardiology, The University of Chicago Medicine, Chicago, IL, USA
| | - Eric J. Brandt
- Section of Cardiology, Yale University School of Medicine, New Haven, CT, USA
| | | |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Wu W, Yin Y, Zhong J, Peng Y, Li S, Zheng L, Cao H, Zhang J. Cell therapy could be a potential way to improve lipoprotein lipase deficiency. Lipids Health Dis 2017; 16:189. [PMID: 28969646 PMCID: PMC5625700 DOI: 10.1186/s12944-017-0577-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 09/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Lipoprotein lipase (LPL) deficiency is an autosomal recessive genetic disorder characterized by extreme hypertriglyceridemia, with no cure presently available. The purpose of this study was to test the possibility of using cell therapy to alleviate LPL deficiency. METHODS The LPL coding sequence was cloned into the MSCV retrovirus vector, after which MSCV-hLPL and MSCV (empty construct without LPL coding sequence) virion suspensions were made using the calcium chloride method. A muscle cell line (C2C12), kidney cell line (HEK293T) and pre-adipocyte cell line (3 T3-L1) were transfected with the virus in order to express recombinant LPL in vitro. Finally, each transfected cell line was injected subcutaneously into nude mice to identify the cell type which could secret recombinant LPL in vivo. Control cells were transfected with the MSCV empty vector. LPL activity was analyzed using a radioimmunoassay. RESULTS After virus infection, the LPL activity at the cell surface of each cell type was significantly higher than in the control cells, which indicates that all three cell types can be used to generate functional LPL. The transfected cells were injected subcutaneously into nude mice, and the LPL activity of the nearby muscle tissue at the injection site in mice injected with 3 T3-L1 cells was more than 5 times higher at the injection sites than at non-injected control sites. The other two types of cells did not show this trend. CONCLUSION The subcutaneous injection of adipocytes overexpressing LPL can improve the LPL activity of the adjacent tissue of nude mice. This is a ground-breaking preliminary study for the treatment of LPL deficiency, and lays a good foundation for using cell therapy to correct LPL deficiency.
Collapse
Affiliation(s)
- Wenjing Wu
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China
| | - Yajun Yin
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China
| | - Jie Zhong
- College of life science and biotechnology, Hebei Normal University of Science and Technology, Qinhuangdao, 066004, China
| | - Yongjia Peng
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China
| | - Shuncai Li
- College of life science and biotechnology, Hebei Normal University of Science and Technology, Qinhuangdao, 066004, China
| | - Libin Zheng
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China
| | - Hong Cao
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China
| | - Jin Zhang
- College of Biological and Chemical Science and Engineering, Jiaxing University, Lianglin Campus,118 Jiahang Road, Jiaxing, 314001, China. .,College of life science and biotechnology, Hebei Normal University of Science and Technology, Qinhuangdao, 066004, China.
| |
Collapse
|
14
|
Kanaki M, Tiniakou I, Thymiakou E, Kardassis D. Physical and functional interactions between nuclear receptor LXRα and the forkhead box transcription factor FOXA2 regulate the response of the human lipoprotein lipase gene to oxysterols in hepatic cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:848-860. [PMID: 28576574 DOI: 10.1016/j.bbagrm.2017.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/17/2017] [Accepted: 05/29/2017] [Indexed: 11/30/2022]
Abstract
Lipoprotein lipase (LPL) catalyzes the hydrolysis of triglycerides from triglyceride-rich lipoproteins such as VLDL and chylomicrons in the circulation. Mutations in LPL or its activator apolipoprotein C-II cause hypertriglyceridemia in humans and animal models. The levels of LPL in the liver are low but they can be strongly induced by a high cholesterol diet or by synthetic ligands of Liver X Receptors (LXRs). However, the mechanism by which LXRs activate the human LPL gene is unknown. In the present study we show that LXR agonists increased the mRNA and protein levels as well as the promoter activity of human LPL in HepG2 cells. A promoter deletion analysis defined the proximal -109/-28 region, which contains a functional FOXA2 element, as essential for transactivation by ligand-activated LXRα/RXRα heterodimers. Silencing of endogenous FOXA2 in HepG2 cells by siRNAs or by treatment with insulin compromised the induction of the LPL gene by LXR agonists whereas mutations in the FOXA2 site abolished the synergistic transactivation of the LPL promoter by LXRα/RXRα and FOXA2. Physical and functional interactions between LXRα and FOXA2 were established in vitro and ex vivo. In summary, the present study revealed a novel mechanism of human LPL gene induction by oxysterols in the liver with is based on physical and functional interactions between transcription factors LXRα and FOXA2. This mechanism, which may not be restricted to the LPL gene, is critically important for a better understanding of the regulation of cholesterol and triglyceride metabolism in the liver under healthy or pathological states.
Collapse
Affiliation(s)
- Maria Kanaki
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Ioanna Tiniakou
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Efstathia Thymiakou
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece
| | - Dimitris Kardassis
- Laboratory of Biochemistry, University of Crete Medical School and Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 71003, Greece,.
| |
Collapse
|
15
|
Kanaki M, Kardassis D. Regulation of the human lipoprotein lipase gene by the forkhead box transcription factor FOXA2/HNF-3β in hepatic cells. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2017; 1860:327-336. [DOI: 10.1016/j.bbagrm.2017.01.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 12/11/2022]
|
16
|
Toxic-metabolic Risk Factors in Pediatric Pancreatitis: Recommendations for Diagnosis, Management, and Future Research. J Pediatr Gastroenterol Nutr 2016; 62:609-17. [PMID: 26594832 PMCID: PMC4805437 DOI: 10.1097/mpg.0000000000001035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pancreatitis in children can result from metabolic and toxic risk factors, but the evidence linking these factors is sparse. We review the evidence for association or causality of these risk factors in pancreatitis, discuss management strategies, and their rationale. We conducted a review of the pediatric pancreatitis literature with respect to the following risk factors: hyperlipidemia, hypercalcemia, chronic renal failure, smoking exposure, alcohol, and medications. Areas of additional research were identified. Hypertriglyceridemia of 1000 mg/dL or greater poses an absolute risk for pancreatitis; persistent elevations of calcium are predisposing. Further research is necessary to determine whether end-stage renal disease leads to increased pancreatitis in children similar to adults. It is unknown whether cigarette smoking exposure, which clearly increases risk in adults, also increases risk in children. The role of alcohol in pediatric pancreatitis, whether direct or modifying, needs to be elucidated. The evidence supporting most cases of medication-induced pancreatitis is poor. Drug structure, improper handling of drug by host, and bystander status may be implicated. Other pancreatitis risk factors must be sought in all cases. The quality of evidence supporting causative role of various toxic and metabolic factors in pediatric pancreatitis is variable. Careful phenotyping is essential, including search for other etiologic risk factors. Directed therapy includes correction/removal of any agent identified, and general supportive measures. Further research is necessary to improve our understanding of these pancreatitis risk factors in children.
Collapse
|
17
|
|
18
|
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.
Collapse
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)
| |
Collapse
|
19
|
Shah AS, Wilson DP. Primary hypertriglyceridemia in children and adolescents. J Clin Lipidol 2015; 9:S20-8. [PMID: 26343209 DOI: 10.1016/j.jacl.2015.04.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 03/25/2015] [Accepted: 04/21/2015] [Indexed: 10/23/2022]
Abstract
Primary disorders of lipid metabolism causing hypertriglyceridemia (HyperTG) result from genetic defects in triglyceride synthesis and metabolism. With the exception of lipoprotein lipase deficiency, these primary HyperTG disorders usually present in adulthood. However, some are unmasked earlier by precipitating factors, such as obesity and insulin resistance, and can be diagnosed in adolescence. Physical findings may be present and can include eruptive, palmer, or tuberoeruptive xanthomas. Triglyceride levels are very high to severe and can occur in the absence or the presence of other lipid abnormalities. Each of the causes of HyperTG is associated with an increased risk to develop recurrent pancreatitis and some may increase the risk of premature cardiovascular disease. Adoption of a healthy lifestyle that includes a low-fat diet, optimizing body weight, smoking avoidance/cessation, and daily physical activity is the first line of therapy. Pharmacologic therapies are available and can be beneficial in select disorders. Here, we review the causes of primary HyperTG in children and adolescents, discuss their clinical presentation and associated complications including the risk of pancreatitis and premature cardiovascular disease, and conclude with management and novel therapies currently in development. The goal of this article is to provide a useful resource for clinicians who may encounter primary HyperTG in the pediatric population.
Collapse
Affiliation(s)
- Amy S Shah
- Department of Pediatric Endocrinology and Diabetes, Cincinnati Children's Hospital Medical Center & the University of Cincinnati, Cincinnati, OH, USA.
| | - Don P Wilson
- Department of Pediatric Endocrinology and Diabetes, Cook Children's Medical Center, Fort Worth, TX, USA
| |
Collapse
|
20
|
Amar MJA, Sakurai T, Sakurai-Ikuta A, Sviridov D, Freeman L, Ahsan L, Remaley AT. A novel apolipoprotein C-II mimetic peptide that activates lipoprotein lipase and decreases serum triglycerides in apolipoprotein E-knockout mice. J Pharmacol Exp Ther 2014; 352:227-35. [PMID: 25395590 DOI: 10.1124/jpet.114.220418] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Apolipoprotein A-I (apoA-I) mimetic peptides are currently being developed as possible new agents for the treatment of cardiovascular disease based on their ability to promote cholesterol efflux and their other beneficial antiatherogenic properties. Many of these peptides, however, have been reported to cause transient hypertriglyceridemia due to inhibition of lipolysis by lipoprotein lipase (LPL). We describe a novel bihelical amphipathic peptide (C-II-a) that contains an amphipathic helix (18A) for binding to lipoproteins and stimulating cholesterol efflux as well as a motif based on the last helix of apolipoprotein C-II (apoC-II) that activates lipolysis by LPL. The C-II-a peptide promoted cholesterol efflux from ATP-binding cassette transporter ABCA1-transfected BHK cells similar to apoA-I mimetic peptides. Furthermore, it was shown in vitro to be comparable to the full-length apoC-II protein in activating lipolysis by LPL. When added to serum from a patient with apoC-II deficiency, it restored normal levels of LPL-induced lipolysis and also enhanced lipolysis in serum from patients with type IV and V hypertriglyceridemia. Intravenous injection of C-II-a (30 mg/kg) in apolipoprotein E-knockout mice resulted in a significant reduction of plasma cholesterol and triglycerides of 38 ± 6% and 85 ± 7%, respectively, at 4 hours. When coinjected with the 5A peptide (60 mg/kg), the C-II-a (30 mg/kg) peptide was found to completely block the hypertriglyceridemic effect of the 5A peptide in C57Bl/6 mice. In summary, C-II-a is a novel peptide based on apoC-II, which promotes cholesterol efflux and lipolysis and may therefore be useful for the treatment of apoC-II deficiency and other forms of hypertriglyceridemia.
Collapse
Affiliation(s)
- Marcelo J A Amar
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Toshihiro Sakurai
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Akiko Sakurai-Ikuta
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Denis Sviridov
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Lita Freeman
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Lusana Ahsan
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - Alan T Remaley
- Lipoprotein Metabolism Section, Cardio-Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| |
Collapse
|
21
|
Wassef H, Davignon J, Prud’homme D, Rabasa-Lhoret R, Faraj M. Changes in total and central fat mass after a hypocaloric diet associate with changes of apoC-I in postmenopausal obese women. J Clin Lipidol 2014; 8:510-9. [DOI: 10.1016/j.jacl.2014.06.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 05/26/2014] [Accepted: 06/09/2014] [Indexed: 10/25/2022]
|
22
|
Talmud PJ, Futema M, Humphries SE. The genetic architecture of the familial hyperlipidaemia syndromes: rare mutations and common variants in multiple genes. Curr Opin Lipidol 2014; 25:274-81. [PMID: 24977977 DOI: 10.1097/mol.0000000000000090] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW Genome-Wide Association Studies have provided robust identification of approximately 100 genetic loci determining plasma lipid parameters. Using these multiple common genetic lipid-determining variants in a 'gene score' has thrown new light on the mode of inheritance of familial lipid disorders. RECENT FINDINGS Different hypertriglyceridaemia states have been explained by the polygenic coinheritance of triglyceride-raising alleles. Taking this gene score approach with 12 LDL-cholesterol-raising alleles, we reported that for patients with a clinical diagnosis of familial hypercholesterolaemia, but no identified rare mutation in the familial hypercholesterolaemia-causing genes, LDL receptor, apolipoprotein B and PCSK9, the most likely explanation for their elevated LDL-C levels was a polygenic, not a monogenic, cause of the disease. SUMMARY These findings have wider implications for understanding complex disorders, and may very well explain the genetic basis of familial combined hyperlipidaemia, another familial lipid disorder in which the genetic cause(s) has remained elusive.
Collapse
Affiliation(s)
- Philippa J Talmud
- Centre for Cardiovascular Genetics, Institute of Cardiovascular Science, University College London, London, UK
| | | | | |
Collapse
|
23
|
Chen TZ, Xie SL, Jin R, Huang ZM. A novel lipoprotein lipase gene missense mutation in Chinese patients with severe hypertriglyceridemia and pancreatitis. Lipids Health Dis 2014; 13:52. [PMID: 24646025 PMCID: PMC3983885 DOI: 10.1186/1476-511x-13-52] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 03/11/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Alterations or mutations in the lipoprotein lipase (LPL) gene contribute to severe hypertriglyceridemia (HTG). This study reported on two patients in a Chinese family with LPL gene mutations and severe HTG and acute pancreatitis. METHODS Two patients with other five family members were included in this study for DNA-sequences of hyperlipidemia-related genes (such as LPL, APOC2, APOA5, LMF1, and GPIHBP1) and 43 healthy individuals and 70 HTG subjects were included for the screening of LPL gene mutations. RESULTS Both patients were found to have a compound heterozygote for a novel LPL gene mutation (L279V) and a known mutation (A98T). Furthermore, one HTG subject out of 70 was found to carry this novel LPL L279V mutation. CONCLUSIONS The data from this study showed that compound heterozygote mutations of A98T and L279V inactivate lipoprotein lipase enzymatic activity and contribute to severe HTG and acute pancreatitis in two Chinese patients. Further study will investigate how these LPL gene mutations genetically inactivate the LPL enzyme.
Collapse
Affiliation(s)
| | | | | | - Zhi-Ming Huang
- The Department of Gastroenterology and Hepatology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China.
| |
Collapse
|
24
|
|
25
|
Larsson M, Vorrsjö E, Talmud P, Lookene A, Olivecrona G. Apolipoproteins C-I and C-III inhibit lipoprotein lipase activity by displacement of the enzyme from lipid droplets. J Biol Chem 2013; 288:33997-34008. [PMID: 24121499 DOI: 10.1074/jbc.m113.495366] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Apolipoproteins (apo) C-I and C-III are known to inhibit lipoprotein lipase (LPL) activity, but the molecular mechanisms for this remain obscure. We present evidence that either apoC-I or apoC-III, when bound to triglyceride-rich lipoproteins, prevent binding of LPL to the lipid/water interface. This results in decreased lipolytic activity of the enzyme. Site-directed mutagenesis revealed that hydrophobic amino acid residues centrally located in the apoC-III molecule are critical for attachment to lipid emulsion particles and consequently inhibition of LPL activity. Triglyceride-rich lipoproteins stabilize LPL and protect the enzyme from inactivating factors such as angiopoietin-like protein 4 (angptl4). The addition of either apoC-I or apoC-III to triglyceride-rich particles severely diminished their protective effect on LPL and rendered the enzyme more susceptible to inactivation by angptl4. These observations were seen using chylomicrons as well as the synthetic lipid emulsion Intralipid. In the presence of the LPL activator protein apoC-II, more of apoC-I or apoC-III was needed for displacement of LPL from the lipid/water interface. In conclusion, we show that apoC-I and apoC-III inhibit lipolysis by displacing LPL from lipid emulsion particles. We also propose a role for these apolipoproteins in the irreversible inactivation of LPL by factors such as angptl4.
Collapse
Affiliation(s)
- Mikael Larsson
- Department of Medical Biosciences/Physiological Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Evelina Vorrsjö
- Department of Medical Biosciences/Physiological Chemistry, Umeå University, SE-901 87 Umeå, Sweden
| | - Philippa Talmud
- Centre for Cardiovascular Genetics, Institute of Cardiovascular Science, University College London, 5 University Street, London WC1E 6JF, United Kingdom
| | - Aivar Lookene
- Department of Chemistry, Tallinn University of Technology, Tallinn 12618, Estonia
| | - Gunilla Olivecrona
- Department of Medical Biosciences/Physiological Chemistry, Umeå University, SE-901 87 Umeå, Sweden.
| |
Collapse
|
26
|
Quiroga AD, Li L, Trötzmüller M, Nelson R, Proctor SD, Köfeler H, Lehner R. Deficiency of carboxylesterase 1/esterase-x results in obesity, hepatic steatosis, and hyperlipidemia. Hepatology 2012; 56:2188-98. [PMID: 22806626 DOI: 10.1002/hep.25961] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Accepted: 06/08/2012] [Indexed: 02/05/2023]
Abstract
UNLABELLED Increased lipogenesis, together with hyperlipidemia and increased fat deposition, contribute to obesity and associated metabolic disorders including nonalcoholic fatty liver disease. Here we show that carboxylesterase 1/esterase-x (Ces1/Es-x) plays a regulatory role in hepatic fat metabolism in the mouse. We demonstrate that Ces1/Es-x knockout mice present with increased hepatic lipogenesis and with oversecretion of apolipoprotein B (apoB)-containing lipoproteins (hepatic very-low density lipoproteins), which leads to hyperlipidemia and increased fat deposition in peripheral tissues. Consequently, Ces1/Es-x knockout mice develop obesity, fatty liver, hyperinsulinemia, and insulin insensitivity on chow diet without change in food intake and present with decreased energy expenditure. Ces1/Es-x deficiency prevents the release of polyunsaturated fatty acids from triacylglycerol stores, leading to an up-regulation of sterol regulatory element binding protein 1c-mediated lipogenesis, which can be reversed with dietary ω-3 fatty acids. CONCLUSION These studies support a role for Ces1/Es-x in the partitioning of regulatory fatty acids and concomitant control of hepatic lipid biosynthesis, secretion, and deposition.
Collapse
Affiliation(s)
- Ariel D Quiroga
- Department of Pediatrics, University of Alberta, Edmonton, Canada
| | | | | | | | | | | | | |
Collapse
|
27
|
Carboxylesterase1/Esterase-x regulates chylomicron production in mice. PLoS One 2012; 7:e49515. [PMID: 23145182 PMCID: PMC3492262 DOI: 10.1371/journal.pone.0049515] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 10/10/2012] [Indexed: 11/30/2022] Open
Abstract
Elevated postprandial plasma triacylglycerol (TG) concentrations are commonly associated with obesity and the risk of cardiovascular disease. Dietary fat contributes to this condition through the production of chylomicrons. Carboxylesterases have been mainly studied for their role in drug metabolism, but recently they have been shown to participate in lipid metabolism; however, their role in intestinal lipid metabolism is unknown. Carboxylesterase1/esterase-x (Ces1/Es-x) deficient mice become obese, hyperlipidemic and develop hepatic steatosis even on standard chow diet. Here, we aimed to explore the role of Ces1/Es-x in intestinal lipid metabolism. Six-month old wild-type and Ces1/Es-x deficient mice were maintained on chow diet and intestinal lipid metabolism and plasma chylomicron clearance were analyzed. Along the intestine Ces1/Es-x protein is expressed only in proximal jejunum. Ablation of Ces1/Es-x expression results in postprandial hyperlipidemia due to increased secretion of chylomicrons. The secreted chylomicrons have aberrant protein composition, which results in their reduced clearance. In conclusion, Ces1/Es-x participates in the regulation of chylomicron assembly and secretion. Ces1/Es-x might act as a lipid sensor in enterocytes regulating chylomicron secretion rate. Ces1/Es-x might represent an attractive pharmacological target for the treatment of lipid abnormalities associated with obesity, insulin resistance and fatty liver disease.
Collapse
|
28
|
Nakajima K, Nakano T, Tokita Y, Nagamine T, Yatsuzuka SI, Shimomura Y, Tanaka A, Sumino H, Nara M, Machida T, Murakami M. The characteristics of remnant lipoproteins in the fasting and postprandial plasma. Clin Chim Acta 2012; 413:1077-86. [DOI: 10.1016/j.cca.2012.02.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 02/18/2012] [Accepted: 02/23/2012] [Indexed: 11/16/2022]
|
29
|
Kostapanos MS, Elisaf MS, Mikhailidis DP. Hypertriglyceridemia-induced acute pancreatitis: clinical considerations. ACTA ACUST UNITED AC 2012. [DOI: 10.2217/clp.12.27] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
30
|
van de Woestijne AP, Monajemi H, Kalkhoven E, Visseren FLJ. Adipose tissue dysfunction and hypertriglyceridemia: mechanisms and management. Obes Rev 2011; 12:829-40. [PMID: 21749607 DOI: 10.1111/j.1467-789x.2011.00900.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Elevated plasma triglyceride levels, as often seen in obese subjects, are independently associated with an increased risk of cardiovascular diseases. By secreting adipokines (such as adiponectin and leptin) and other proteins (such as lipoprotein lipase and cholesteryl ester transferase protein), adipose tissue affects triglyceride metabolism. In obesity, adipocyte hypertrophy leads to many changes in adipocyte function and production of anti- and pro-inflammatory cytokines. Furthermore, free fatty acids are released into the circulation contributing to insulin resistance. Adipose tissue dysfunction will eventually lead to abnormalities in lipid metabolism, such as hypertriglyceridemia (due to increased hepatic very-low-density lipoprotein production and decreased triglyceride hydrolysis), small dense low-density lipoprotein particles, remnant lipoproteins and low high-density lipoprotein cholesterol levels, all associated with a higher risk for the development of cardiovascular diseases. The clinical implications of elevated plasma triglycerides are still a matter of debate. Understanding the pathophysiology of adipose tissue dysfunction in obesity, which is becoming a pandemic condition, is essential for designing appropriate therapeutic interventions. Lifestyle changes are important to improve adipose tissue function in obese patients. Pharmacological interventions to improve adipose tissue function need further evaluation. Although statins are not very potent in reducing plasma triglycerides, they remain the mainstay of therapy for cardiovascular risk reduction in high-risk patients.
Collapse
Affiliation(s)
- A P van de Woestijne
- Department of Vascular Medicine, University Medical Center, Utrecht, the Netherlands Department of Metabolic and Endocrine Diseases, University Medical Center, Utrecht, the Netherlands
| | | | | | | |
Collapse
|
31
|
Abstract
PURPOSE OF REVIEW Hypertriglyceridemia (HTG) is a common diagnosis. Although secondary factors are important for clinical expression, susceptibility to HTG has a strong genetic component, which we review here. RECENT FINDINGS Severe HTG in a few families follows Mendelian - typically autosomal recessive - inheritance of rare loss-of-function mutations in genes such as LPL, APOC2, APOA5, LMF1, and GPIHBP1. In contrast, common complex HTG results from the cumulative influence of small-effect variants (single nucleotide polymorphisms) in genes such as APOA5, GCKR, LPL, and APOB. Intensive resequencing of these four genes has also shown accumulated heterozygous rare variants in HTG patients. Together, more than 20% of the susceptibility to HTG is now accounted for by common and rare variants. Further, classical Fredrickson HTG phenotypes, which were once considered to be distinct based on biochemical features, have a shared genetic architecture. SUMMARY Compared to other complex traits, genetic variants account for a high proportion of HTG diagnoses. By tallying the number of HTG risk alleles, it is possible to discriminate between individuals with HTG and normolipidemia, particularly in those with extreme scores. Future directions include finding the missing genetic component and determining whether genetic profiling can help with diagnosis or personalized treatment advice.
Collapse
Affiliation(s)
- Christopher T Johansen
- Departments of Biochemistry and Medicine, Robarts Research Institute and Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | | |
Collapse
|
32
|
Nakajima K, Nakano T, Tokita Y, Nagamine T, Inazu A, Kobayashi J, Mabuchi H, Stanhope KL, Havel PJ, Okazaki M, Ai M, Tanaka A. Postprandial lipoprotein metabolism: VLDL vs chylomicrons. Clin Chim Acta 2011; 412:1306-18. [PMID: 21531214 PMCID: PMC3265327 DOI: 10.1016/j.cca.2011.04.018] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 04/11/2011] [Accepted: 04/12/2011] [Indexed: 12/31/2022]
Abstract
Since Zilversmit first proposed postprandial lipemia as the most common risk of cardiovascular disease, chylomicrons (CM) and CM remnants have been thought to be the major lipoproteins which are increased in the postprandial hyperlipidemia. However, it has been shown over the last two decades that the major increase in the postprandial lipoproteins after food intake occurs in the very low density lipoprotein (VLDL) remnants (apoB-100 particles), not CM or CM remnants (apoB-48 particles). This finding was obtained using the following three analytical methods; isolation of remnant-like lipoprotein particles (RLP) with specific antibodies, separation and detection of lipoprotein subclasses by gel permeation HPLC and determination of apoB-48 in fractionated lipoproteins by a specific ELISA. The amount of the apoB-48 particles in the postprandial RLP is significantly less than the apoB-100 particles, and the particle sizes of apoB-48 and apoB-100 in RLP are very similar when analyzed by HPLC. Moreover, CM or CM remnants having a large amount of TG were not found in the postprandial RLP. Therefore, the major portion of the TG which is increased in the postprandial state is composed of VLDL remnants, which have been recognized as a significant risk for cardiovascular disease.
Collapse
Affiliation(s)
- Katsuyuki Nakajima
- School of Health Sciences, Faculty of Medicine, Gunma University, Maebashi, Gunma, Japan.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Mutations in lipoprotein lipase that block binding to the endothelial cell transporter GPIHBP1. Proc Natl Acad Sci U S A 2011; 108:7980-4. [PMID: 21518912 DOI: 10.1073/pnas.1100992108] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
GPIHBP1, a glycosylphosphatidylinositol-anchored protein of capillary endothelial cells, shuttles lipoprotein lipase (LPL) from subendothelial spaces to the capillary lumen. An absence of GPIHBP1 prevents the entry of LPL into capillaries, blocking LPL-mediated triglyceride hydrolysis and leading to markedly elevated triglyceride levels in the plasma (i.e., chylomicronemia). Earlier studies have established that chylomicronemia can be caused by LPL mutations that interfere with catalytic activity. We hypothesized that some cases of chylomicronemia might be caused by LPL mutations that interfere with LPL's ability to bind to GPIHBP1. Any such mutation would provide insights into LPL sequences required for GPIHBP1 binding. Here, we report that two LPL missense mutations initially identified in patients with chylomicronemia, C418Y and E421K, abolish LPL's ability to bind to GPIHBP1 without interfering with LPL catalytic activity or binding to heparin. Both mutations abolish LPL transport across endothelial cells by GPIHBP1. These findings suggest that sequences downstream from LPL's principal heparin-binding domain (amino acids 403-407) are important for GPIHBP1 binding. In support of this idea, a chicken LPL (cLPL)-specific monoclonal antibody, xCAL 1-11 (epitope, cLPL amino acids 416-435), blocks cLPL binding to GPIHBP1 but not to heparin. Also, changing cLPL residues 421 to 425, 426 to 430, and 431 to 435 to alanine blocks cLPL binding to GPIHBP1 without inhibiting catalytic activity. Together, these data define a mechanism by which LPL mutations could elicit disease and provide insights into LPL sequences required for binding to GPIHBP1.
Collapse
|
34
|
Hoofnagle AN, Heinecke JW. Lipoproteomics: using mass spectrometry-based proteomics to explore the assembly, structure, and function of lipoproteins. J Lipid Res 2010; 50:1967-75. [PMID: 19738003 DOI: 10.1194/jlr.r900015-jlr200] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Lipoproteins are centrally important in lipid transport, fuel metabolism, and cardiovascular disease. The prototypic lipoprotein has an outer shell of amphipathic lipids and proteins that solubilizes a hydrophobic lipid core. Lipoprotein-associated proteins have classically been viewed as structural elements and factors important in lipid metabolism. Recent mass spectrometric analyses reveal that the protein cargo of lipoproteins is much more diverse than previously appreciated, raising the possibility that lipoproteins play previously unsuspected roles in host defense mechanisms and inflammation. They further suggest that lipoprotein-associated proteins can identify humans at increased risk of cardiovascular disease. Here, we summarize recent developments in lipoproteomics, the proteomic analysis of lipoproteins. We also discuss the promises and challenges this powerful analytical strategy offers for expanding our understanding of the biology and structures of lipoproteins.
Collapse
Affiliation(s)
- Andrew N Hoofnagle
- Department of Laboratory Medicine, University of Washington, Seattle, WA, USA.
| | | |
Collapse
|
35
|
The effects of ezetimibe and/or orlistat on triglyceride-rich lipoprotein metabolism in obese hypercholesterolemic patients. Lipids 2010; 45:445-50. [PMID: 20379853 DOI: 10.1007/s11745-010-3409-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 03/15/2010] [Indexed: 01/21/2023]
Abstract
We investigated the factors influencing triglycerides (TG) reduction during ezetimibe, alone or combined with orlistat, administration. Eighty-six obese hypercholesterolemic subjects were prescribed a low-fat diet and were randomized to ezetimibe (E group), orlistat (O group), or both (OE group) for 6 months. Plasma TG and apolipoprotein (apo) C-III reduction was significantly greater in the combination group compared with monotherapy. Multivariate analysis showed that in E group apoC-III reduction and baseline TG levels were independently positively correlated, whereas baseline apoC-II levels were negatively correlated, with TG lowering. In OE group apoC-III reduction was the only independent contributor to TG reduction.
Collapse
|
36
|
|
37
|
Avis HJ, Scheffer HJ, Kastelein JJP, Dallinga-Thie GM, Wijburg FA. Pink-creamy whole blood in a 3-month-old infant with a homozygous deletion in the lipoprotein lipase gene. Clin Genet 2010; 77:430-3. [PMID: 20095985 DOI: 10.1111/j.1399-0004.2009.01369.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- H J Avis
- Department of Pediatrics, Academic Medical Center, Amsterdam, The Netherlands.
| | | | | | | | | |
Collapse
|
38
|
Olivecrona G, Ehrenborg E, Semb H, Makoveichuk E, Lindberg A, Hayden MR, Gin P, Davies BSJ, Weinstein MM, Fong LG, Beigneux AP, Young SG, Olivecrona T, Hernell O. Mutation of conserved cysteines in the Ly6 domain of GPIHBP1 in familial chylomicronemia. J Lipid Res 2009; 51:1535-45. [PMID: 20026666 DOI: 10.1194/jlr.m002717] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We investigated a family from northern Sweden in which three of four siblings have congenital chylomicronemia. LPL activity and mass in pre- and postheparin plasma were low, and LPL release into plasma after heparin injection was delayed. LPL activity and mass in adipose tissue biopsies appeared normal. [(35)S]Methionine incorporation studies on adipose tissue showed that newly synthesized LPL was normal in size and normally glycosylated. Breast milk from the affected female subjects contained normal to elevated LPL mass and activity levels. The milk had a lower than normal milk lipid content, and the fatty acid composition was compatible with the milk lipids being derived from de novo lipogenesis, rather than from the plasma lipoproteins. Given the delayed release of LPL into the plasma after heparin, we suspected that the chylomicronemia might be caused by mutations in GPIHBP1. Indeed, all three affected siblings were compound heterozygotes for missense mutations involving highly conserved cysteines in the Ly6 domain of GPIHBP1 (C65S and C68G). The mutant GPIHBP1 proteins reached the surface of transfected Chinese hamster ovary cells but were defective in their ability to bind LPL (as judged by both cell-based and cell-free LPL binding assays). Thus, the conserved cysteines in the Ly6 domain are crucial for GPIHBP1 function.
Collapse
Affiliation(s)
- Gunilla Olivecrona
- Department of Medical Biosciences/Physiological Chemistry, Umeå University, Umeå, Sweden.
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Abstract
Lipoprotein lipase (LPL) is a multifunctional enzyme produced by many tissues, including adipose tissue, cardiac and skeletal muscle, islets, and macrophages. LPL is the rate-limiting enzyme for the hydrolysis of the triglyceride (TG) core of circulating TG-rich lipoproteins, chylomicrons, and very low-density lipoproteins (VLDL). LPL-catalyzed reaction products, fatty acids, and monoacylglycerol are in part taken up by the tissues locally and processed differentially; e.g., they are stored as neutral lipids in adipose tissue, oxidized, or stored in skeletal and cardiac muscle or as cholesteryl ester and TG in macrophages. LPL is regulated at transcriptional, posttranscriptional, and posttranslational levels in a tissue-specific manner. Nutrient states and hormonal levels all have divergent effects on the regulation of LPL, and a variety of proteins that interact with LPL to regulate its tissue-specific activity have also been identified. To examine this divergent regulation further, transgenic and knockout murine models of tissue-specific LPL expression have been developed. Mice with overexpression of LPL in skeletal muscle accumulate TG in muscle, develop insulin resistance, are protected from excessive weight gain, and increase their metabolic rate in the cold. Mice with LPL deletion in skeletal muscle have reduced TG accumulation and increased insulin action on glucose transport in muscle. Ultimately, this leads to increased lipid partitioning to other tissues, insulin resistance, and obesity. Mice with LPL deletion in the heart develop hypertriglyceridemia and cardiac dysfunction. The fact that the heart depends increasingly on glucose implies that free fatty acids are not a sufficient fuel for optimal cardiac function. Overall, LPL is a fascinating enzyme that contributes in a pronounced way to normal lipoprotein metabolism, tissue-specific substrate delivery and utilization, and the many aspects of obesity and other metabolic disorders that relate to energy balance, insulin action, and body weight regulation.
Collapse
Affiliation(s)
- Hong Wang
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, USA
| | | |
Collapse
|
40
|
Rahalkar AR, Giffen F, Har B, Ho J, Morrison KM, Hill J, Wang J, Hegele RA, Joy T. Novel LPL mutations associated with lipoprotein lipase deficiency: two case reports and a literature review. Can J Physiol Pharmacol 2009; 87:151-60. [PMID: 19295657 DOI: 10.1139/y09-005] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lipoprotein lipase (LPL) is a key enzyme involved with hydrolysis and removal of triglycerides from plasma. LPL deficiency is a rare condition with an estimated prevalence of 1 in 106. It is characterized biochemically by elevated triglycerides and lowered HDL in the plasma and clinically by a constellation of signs and symptoms during childhood including failure to thrive, lipemia retinalis, eruptive xanthomas, hepatosplenomegaly, and acute pancreatitis. Nearly 100 mutations in the LPL gene have been associated with LPL deficiency. Here we report 2 unrelated pedigrees with LPL deficiency from 2 novel disease-causing LPL mutations: a Gly159Glu missense mutation in exon 5 and a 4-bp ACGG deletion at the 3' boundary of exon 2. We present molecular findings of these 2 cases and review the biochemical, clinical, and genetic features of LPL deficiency.
Collapse
Affiliation(s)
- Amit R Rahalkar
- Department of Vascular Biology and Medicine, Robarts Research Institute and Schulich School of Medicine and Dentistry, University of Western Ontario, P.O. Box 5015, 100 Perth Drive, London, ON N6A5K8, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|
41
|
Béliard S, Nogueira JP, Maraninchi M, Lairon D, Nicolay A, Giral P, Portugal H, Vialettes B, Valéro R. Parallel increase of plasma apoproteins C-II and C-III in Type 2 diabetic patients. Diabet Med 2009; 26:736-9. [PMID: 19573124 DOI: 10.1111/j.1464-5491.2009.02757.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To determine plasma levels of apoprotein (apo) C-II and apoprotein C-III in Type 2 diabetic patients and to examine the clinical and biological factors that are associated with elevated apoC concentrations. METHODS We measured apoC-II and apoC-III in total plasma and in non-high-density lipoprotein fractions by an immunoturbidimetric assay in 88 Caucasian Type 2 diabetic patients and in 138 healthy control subjects. RESULTS Plasma levels of both apoC-II and apoC-III were increased in Type 2 diabetic patients. The clinical conditions associated with an increase of plasma apoC-II and apoC-III were abdominal obesity, body mass index, poor glycaemic control and lack of insulin treatment. However, when multivariate analysis was used, plasma apoCs levels correlated with triglyceride levels only. The apoC-III/apoC-II ratio was similar in the Type 2 diabetic and control subjects. CONCLUSIONS Our study shows the parallel increase of apoC-II and C-III in Type 2 diabetic patients. This parallel increase is related to hypertriglyceridaemia only.
Collapse
Affiliation(s)
- S Béliard
- Department of Nutrition, Metabolic Diseases, Endocrinology, University of Aix-Marseille 2, La Timone Hospital, France
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Lipoprotein lipase mutation S447X associated with pancreatic calcification and steatorrhea in hyperlipidemic pancreatitis. J Clin Gastroenterol 2009; 43:591-6. [PMID: 19034041 DOI: 10.1097/mcg.0b013e3181734a30] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND The factors that whether and how genes involving lipid metabolism including lipoprotein lipase (LPL) and apolipoprotein CII (apo CII) influence occurrence of acute attack of pancreatitis and chronic pancreatitis is not clear. GOALS The aim of this study was to determine the association of LPL and apo CII genes with acute attack of pancreatitis and chronic pancreatitis in patients with hyperlipidemic pancreatitis (HLP) and hypertriglyceridemia (HTG). STUDY We performed genetic analysis of 134 patients in Taiwan with HTG (53 with HLP and 81 without HLP). The entire coding and intronic regions of the LPL and apo CII genes were identified with heteroduplex analytical techniques or high resolution melting analysis. All mutations were confirmed by sequencing analysis. Correlation of phenotype and genotype was also analyzed. RESULTS The frequency of LPL gene mutation rates in HLP patients (17.0%, 9 of 53) was significantly higher than that without HLP attack (4.9%, 4 of 81) (P<0.0001). A total of 10.4% (14 of 134) of our HTG patients carried LPL or apo CII mutation. The most common LPL gene mutation was S447X. There is a high prevalence (77.8%) of HLP attack in HTG patients carrying S447X mutation. Multivariate analysis in HLP patients indicated that the presence of LPL mutation and episode of acute attack were independent risks for pancreatic calcification and steatorrhea. CONCLUSIONS This is the first complete genetic study analyzing the association of LPL and apo CII mutation in a HLP population. LPL S447X mutation is associated with a higher risk of pancreatic calcification and steatorrhea than those previously known factors in HLP patients.
Collapse
|
43
|
Abstract
Susceptibility to the growing global public health problem of cardiovascular disease is associated with levels of plasma lipids and lipoproteins. Several experimental strategies have helped us to clarify the genetic architecture of these complex traits, including classical studies of monogenic dyslipidaemias, resequencing, phenomic analysis and, more recently, genome-wide association studies and analysis of metabolic networks. The genetic basis of plasma lipoprotein levels can now be modelled as a mosaic of contributions from multiple DNA sequence variants, both rare and common, with varying effect sizes. In addition to filling gaps in our understanding of plasma lipoprotein metabolism, the recent genetic advances will improve our ability to classify, diagnose and treat dyslipidaemias.
Collapse
Affiliation(s)
- Robert A Hegele
- Robarts Research Institute and Schulich School of Medicine and Dentistry, University of Western Ontario, 406-100 Perth Drive, London, Ontario, Canada N6A 5K8.
| |
Collapse
|
44
|
Effect of plasma triglyceride metabolism on lipid storage in adipose tissue: studies using genetically engineered mouse models. Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:479-85. [PMID: 19168150 DOI: 10.1016/j.bbalip.2008.12.015] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Revised: 12/11/2008] [Accepted: 12/23/2008] [Indexed: 01/15/2023]
Abstract
The obesity epidemic is associated with an increased incidence of type 2 diabetes, cardiovascular morbidity and various types of cancer. A better insight into the molecular mechanisms that underlie adipogenesis and obesity may result in novel therapeutic handles to fight obesity and these associated diseases. Adipogenesis is determined by the balance between uptake of fatty acids (FA) from plasma into adipocytes, intracellular FA oxidation versus esterification of FA into triglycerides (TG), lipolysis of TG by intracellular lipases, and secretion of FA from adipocytes. Here, we review the mechanisms that are specifically involved in the entry of FA into adipose tissue. In plasma, these originating FA are either present as TG within apoB-containing lipoproteins (i.e. chylomicrons and VLDL) or as free FA bound to albumin. Kinetic studies, however, have revealed that TG are the major source of FA entering adipose tissue, both in the fed and fasted condition. In fact, studies with genetically engineered mice have revealed that the activity of lipoprotein lipase (LPL) is a major determinant for the development of obesity. As a general rule, high fat diet-induced adipogenesis is aggravated by stimulated LPL activity (e.g. by adipose tissue-specific overexpression of LPL or deficiency for apoCIII), and attenuated by inhibited LPL activity (e.g. by adipose-specific deficiency for LPL, overexpression of apoCI or angptl4, or by deficiency for apoE or the VLDL receptor). In addition, we describe that the trans-membrane transport of FA and cytoplasmic binding of FA in adipocytes can also dramatically affect adipogenesis. The relevance of these findings for human pathophysiology is discussed.
Collapse
|
45
|
Sato I, Ishikawa Y, Ishimoto A, Katsura S, Toyokawa A, Hayashi F, Kawano S, Fujioka Y, Yamashita S, Kumagai S. Significance of Measuring Serum Concentrations of Remnant Lipoproteins and Apolipoprotein B-48 in Fasting Period. J Atheroscler Thromb 2009; 16:12-20. [DOI: 10.5551/jat.e596] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
|
46
|
Abstract
While the precise definition of hypertriglyceridaemia remains contentious, the condition is becoming more common in western populations as the prevalence of obesity and diabetes mellitus rise. Although there is strong epidemiological evidence that hypertriglyceridaemia is an independent risk factor for cardiovascular disease, it is has been difficult to demonstrate this by drug intervention studies, as drugs that reduce triglycerides also raise high density lipoprotein cholesterol. Precise target values have also been difficult to agree, although several of the new guidelines for coronary risk management now include triglycerides. The causes of hypertriglyceridaemia are numerous. The more severe forms have a genetic basis, and may lead to an increased risk of pancreatitis. Several types of hypertriglyceridaemia are familial and are associated with increased cardiovascular risk. Secondary causes of hypertriglyceridaemia are also numerous and it is important to exclude these before starting treatment with specific triglyceride-lowering agents. Lifestyle management is also very effective and includes weight reduction, restricted alcohol and fat intake and exercise.
Collapse
|
47
|
Filippatos TD, Tsimihodimos V, Kostapanos M, Kostara C, Bairaktari ET, Kiortsis DN, Elisaf MS. Analysis of 6-month effect of orlistat administration, alone or in combination with fenofibrate, on triglyceride-rich lipoprotein metabolism in overweight and obese patients with metabolic syndrome. J Clin Lipidol 2008; 2:279-84. [PMID: 21291744 DOI: 10.1016/j.jacl.2008.06.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2008] [Revised: 03/23/2008] [Accepted: 06/08/2008] [Indexed: 12/12/2022]
Abstract
BACKGROUND Orlistat significantly reduced serum triglycerides (TG) in most clinical trials. Orlistat-induced TG reduction has not been studied to determine the factors contributing to TG alterations in clinical settings. OBJECTIVE We examined the factors influencing TG reduction during orlistat administration, alone or in combination with fenofibrate, and we investigated the effects of these treatments on apolipoprotein C-II (ApoC-II) and C-III (ApoC-III) levels. METHODS Patients with the metabolic syndrome were randomly allocated to receive orlistat 120 mg three times daily (n = 28, O group), micronized fenofibrate 200 mg/day (n = 28, F group), or both (n = 27, OF group) for 6 months. Plasma ApoC-II and ApoC-III were determined by an immunoturbidimetric assay. RESULTS In the O group, we observed reductions of plasma ApoC-III (P < 0.05) and ApoC-II (P = NS) levels. Fenofibrate administration significantly reduced concentrations of ApoC-II and ApoC-III, whereas the combination of orlistat and fenofibrate had an additive effect on these apolipoproteins. There were significant in-group reductions in serum TG levels in all treatment groups. Multivariate analysis showed that in O group's baseline TG levels were independently positively correlated, whereas the baseline ApoC-II levels were negatively correlated with TG-lowering. In the F group, baseline TG levels and ApoC-III reduction were significantly and independently correlated with TG reduction. OF group's baseline TG levels and ApoC-III reduction were independently positively correlated and baseline ApoC-II levels were negatively correlated with TG-lowering. CONCLUSIONS Orlistat-mediated TG-lowering is independently associated with baseline TG and ApoC-II levels. When orlistat is combined with fenofibrate, ApoC-III reduction is another independent contributor to TG alterations.
Collapse
Affiliation(s)
- Theodosios D Filippatos
- Department of Internal Medicine, School of Medicine, University of Ioannina, 45 110 Ioannina, Greece
| | | | | | | | | | | | | |
Collapse
|
48
|
|
49
|
Rahalkar AR, Hegele RA. Monogenic pediatric dyslipidemias: classification, genetics and clinical spectrum. Mol Genet Metab 2008; 93:282-94. [PMID: 18023224 DOI: 10.1016/j.ymgme.2007.10.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 10/09/2007] [Accepted: 10/09/2007] [Indexed: 12/20/2022]
Abstract
Monogenic disorders that cause abnormal levels of plasma cholesterol and triglycerides have received much attention due to their role in metabolic dysfunction and cardiovascular disease. While these disorders often present clinically during adulthood, some present most commonly in the pediatric population and can have serious consequences if misdiagnosed or untreated. This review provides an overview of monogenic lipid disorders that present with unusually high or low levels of plasma cholesterol and/or triglycerides during infancy, childhood and adolescence. Biochemical and genetic findings, clinical presentation and treatment options are discussed with an emphasis upon recent advances in our understanding and management of these monogenic disorders.
Collapse
Affiliation(s)
- Amit R Rahalkar
- Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ont., Canada
| | | |
Collapse
|
50
|
Wang J, Cao H, Ban MR, Kennedy BA, Zhu S, Anand S, Yusuf S, Pollex RL, Hegele RA. Resequencing Genomic DNA of Patients With Severe Hypertriglyceridemia (MIM 144650). Arterioscler Thromb Vasc Biol 2007; 27:2450-5. [PMID: 17717288 DOI: 10.1161/atvbaha.107.150680] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Objective—
The genetic determinants of severe hypertriglyceridemia (HTG; MIM 144650) in adults are poorly defined. We therefore resequenced 3 candidate genes, namely
LPL
,
APOC2
, and
APOA5
, to search for accumulation of missense mutations in patients with severe HTG compared with normolipidemic subjects.
Methods and Results—
We resequenced >2 million base pairs of genomic DNA from 110 nondiabetic patients with severe HTG and determined the prevalence of coding sequence variants compared with 472 age- and sex-matched normolipidemic controls. We found: (1) heterozygous mutations (
LPL
p.Q-12E >11X, p.D25H, p.W86R, p.G188E, p.I194T and p.P207L;
APOC2
p.K19T and IVS2–30G>A) in 10.0% of severe HTG patients compared with 0.2% of controls (carrier odds ratio [OR] 52, 95% confidence interval [CI] 8.6 to 319); and (2) an association of the
APOA5
p.S19W missense variant with severe HTG (carrier OR 5.5 95% CI 3.3 to 9.1). Furthermore, either rare mutations or the
APOA5
p.S19W variant were found in 41.8% of HTG subjects compared with 8.9% of controls (carrier OR 7.4, 95% CI 4.5 to 12.0). Also, heterozygotes for rare mutations had a significantly reduced plasma triglyceride response to fibrate monotherapy.
Conclusions—
Both common and rare DNA variants in candidate genes were found in a substantial proportion of severe HTG patients. The findings underscore the value of candidate gene resequencing to understand the genetic contribution in complex lipoprotein and metabolic disorders.
Collapse
Affiliation(s)
- Jian Wang
- Vascular Biology Research Group, Robarts Research Institute and Schulich School of Medicine and Dentistry, London, Ontario, Canada
| | | | | | | | | | | | | | | | | |
Collapse
|