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Paquette M, Baass A. Advances in familial hypercholesterolemia. Adv Clin Chem 2024; 119:167-201. [PMID: 38514210 DOI: 10.1016/bs.acc.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024]
Abstract
Familial hypercholesterolemia (FH), a semi-dominant genetic disease affecting more than 25 million people worldwide, is associated with severe hypercholesterolemia and premature atherosclerotic cardiovascular disease. Over the last decade, advances in data analysis, screening, diagnosis and cardiovascular risk stratification has significantly improved our ability to deliver precision medicine for these patients. Furthermore, recent updates on guideline recommendations and new therapeutic approaches have also proven to be highly beneficial. It is anticipated that both ongoing and upcoming clinical trials will offer further insights for the care and treatment of FH patients.
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Affiliation(s)
- Martine Paquette
- Genetic Dyslipidemias Clinic of the Montreal Clinical Research Institute, Montreal, QC, Canada
| | - Alexis Baass
- Genetic Dyslipidemias Clinic of the Montreal Clinical Research Institute, Montreal, QC, Canada; Department of Medicine, Divisions of Experimental Medicine and Medical Biochemistry, McGill University, Montreal, QC, Canada.
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2
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Abstract
PURPOSE OF REVIEW We reviewed current and future therapeutic options for patients with homozygous familial hypercholesterolemia (HoFH) and place this evidence in context of an adaptable treatment algorithm. RECENT FINDINGS Lowering LDL-C levels to normal in patients with HoFH is challenging, but a combination of multiple lipid-lowering therapies (LLT) is key. Patients with (near) absence of LDL receptor expression are most severely affected and frequently require regular lipoprotein apheresis on top of combined pharmacologic LLT. Therapies acting independently of the LDL receptor pathway, such as lomitapide and evinacumab, are considered game changers for many patients with HoFH, and may reduce the need for lipoprotein apheresis in future. Liver transplantation is to be considered a treatment option of last resort. Headway is being made in gene therapy strategies, either aiming to permanently replace or knock out key lipid-related genes, with first translational steps into humans being made. Cardiovascular disease risk management beyond LDL-C, such as residual Lp(a) or inflammatory risk, should be evaluated and addressed accordingly in HoFH. SUMMARY Hypercholesterolemia is notoriously difficult to control in most patients with HoFH, but multi-LLT, including newer drugs, allows reduction of LDL-C to levels unimaginable until a few years ago. Cost and availability of these new therapies are important future challenges to be addressed.
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Affiliation(s)
- Tycho R. Tromp
- Department of Vascular Medicine, Amsterdam UMC, Location AMC, Amsterdam, The Netherlands
| | - Marina Cuchel
- Department of Medicine, Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Glavinovic T, Thanassoulis G, de Graaf J, Couture P, Hegele RA, Sniderman AD. Physiological Bases for the Superiority of Apolipoprotein B Over Low-Density Lipoprotein Cholesterol and Non-High-Density Lipoprotein Cholesterol as a Marker of Cardiovascular Risk. J Am Heart Assoc 2022; 11:e025858. [PMID: 36216435 PMCID: PMC9673669 DOI: 10.1161/jaha.122.025858] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In 2019, the European Society of Cardiology/European Atherosclerosis Society stated that apolipoprotein B (apoB) was a more accurate marker of cardiovascular risk than low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol. Since then, the evidence has continued to mount in favor of apoB. This review explicates the physiological mechanisms responsible for the superiority of apoB as a marker of the cardiovascular risk attributable to the atherogenic apoB lipoprotein particles chylomicron remnants, very low-density lipoprotein, and low-density lipoprotein particles. First, the nature and relative numbers of these different apoB particles will be outlined. This will make clear why low-density lipoprotein particles are almost always the major determinants of cardiovascular risk and why the concentrations of triglycerides and LDL-C may obscure this relation. Next, the mechanisms that govern the number of very low-density lipoprotein and low-density lipoprotein particles will be outlined because, except for dysbetalipoproteinemia, the total number of apoB particles determines cardiovascular risk, Then, the mechanisms that govern the cholesterol mass within very low-density lipoprotein and low-density lipoprotein particles will be reviewed because these are responsible for the discordance between the mass of cholesterol within apoB particles, measured either as LDL-C or non-high-density lipoprotein cholesterol, and the number of apoB particles measured as apoB, which creates the superior predictive power of apoB over LDL-C and non-high-density lipoprotein cholesterol. Finally, the major apoB dyslipoproteinemias will be briefly outlined. Our objective is to provide a physiological framework for health care givers to understand why apoB is a more accurate marker of cardiovascular risk than LDL-C or non-high-density lipoprotein cholesterol.
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Affiliation(s)
- Tamara Glavinovic
- Division of Nephrology, Department of MedicineMcGill University Health CentreMontrealQuebecCanada
| | - George Thanassoulis
- Mike and Valeria Centre for Cardiovascular Prevention, Department of MedicineMcGill University Health CentreMontrealQuebecCanada
| | - Jacqueline de Graaf
- University of Nijmegen Radboud University Medical CenterDepartment of General Internal MedicineNijmegenthe Netherlands
| | - Patrick Couture
- Université LavalCentre Hospitalier Universitaire de QuébecQuebecCanada
| | - Robert A. Hegele
- Robarts Research Institute and Department of Medicine, Schulich School of Medicine and DentistryWestern UniversityLondonOntarioCanada
| | - Allan D. Sniderman
- Mike and Valeria Centre for Cardiovascular Prevention, Department of MedicineMcGill University Health CentreMontrealQuebecCanada
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4
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Sarkar SK, Matyas A, Asikhia I, Hu Z, Golder M, Beehler K, Kosenko T, Lagace TA. Pathogenic gain-of-function mutations in the prodomain and C-terminal domain of PCSK9 inhibit LDL binding. Front Physiol 2022; 13:960272. [PMID: 36187800 PMCID: PMC9515655 DOI: 10.3389/fphys.2022.960272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 08/23/2022] [Indexed: 11/30/2022] Open
Abstract
Proprotein convertase subtilisin/kexin type-9 (PCSK9) is a secreted protein that binds and mediates endo-lysosomal degradation of low-density lipoprotein receptor (LDLR), limiting plasma clearance of cholesterol-rich LDL particles in liver. Gain-of-function (GOF) point mutations in PCSK9 are associated with familial hypercholesterolemia (FH). Approximately 30%–40% of PCSK9 in normolipidemic human plasma is bound to LDL particles. We previously reported that an R496W GOF mutation in a region of PCSK9 known as cysteine-histidine–rich domain module 1 (CM1) prevents LDL binding in vitro [Sarkar et al., J. Biol. Chem. 295 (8), 2285–2298 (2020)]. Herein, we identify additional GOF mutations that inhibit LDL association, localized either within CM1 or a surface-exposed region in the PCSK9 prodomain. Notably, LDL binding was nearly abolished by a prodomain S127R GOF mutation, one of the first PCSK9 mutations identified in FH patients. PCSK9 containing alanine or proline substitutions at amino acid position 127 were also defective for LDL binding. LDL inhibited cell surface LDLR binding and degradation induced by exogenous PCSK9-D374Y but had no effect on an S127R-D374Y double mutant form of PCSK9. These studies reveal that multiple FH-associated GOF mutations in two distinct regions of PCSK9 inhibit LDL binding, and that the Ser-127 residue in PCSK9 plays a critical role.
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Affiliation(s)
- Samantha K. Sarkar
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Angela Matyas
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Ikhuosho Asikhia
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Zhenkun Hu
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Mia Golder
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | | | - Tanja Kosenko
- University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Thomas A. Lagace
- Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
- University of Ottawa Heart Institute, Ottawa, ON, Canada
- *Correspondence: Thomas A. Lagace,
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5
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Bajaj A, Cuchel M. Advancements in the Treatment of Homozygous Familial Hypercholesterolemia. J Atheroscler Thromb 2022; 29:1125-1135. [PMID: 35466160 PMCID: PMC9371762 DOI: 10.5551/jat.rv17065] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Homozygous familial hypercholesterolemia (HoFH) is a rare genetic disorder with extreme elevations of low-density lipoprotein cholesterol (LDL-C) leading to premature atherosclerotic cardiovascular disease (ASCVD) as early as in childhood. Management of HoFH centers around aggressive and adequate reduction of LDL-C levels to slow the trajectory of ASCVD development. Historically, lowering LDL-C levels in HoFH has been challenging because of both the markedly elevated LDL-C levels (often >400 mg/dL) and reduced response to treatment options, such as statins, for which the mechanism of action requires a functional LDL receptor. However, the treatment landscape for HoFH has rapidly progressed over the last decade. While statins and ezetimibe remain first-line treatment, patients often require addition of multiple therapies to achieve goal LDL-C levels. The PCSK9 inhibitors are an important recent addition to the available treatment options, along with lomitapide, bile acid sequestrants, and, possibly, bempedoic acid. Additionally, ANGPTL3 has emerged as an important therapeutic target, with evinacumab being the first available ANGPTL3 inhibitor on the market for the treatment of patients with HoFH. For patients who cannot achieve adequate LDL-C reduction, lipoprotein apheresis may be necessary, with the added benefit of reducing lipoprotein(a) levels that carries an added risk if also elevated in patients with HoFH. Finally, gene therapy and genome editing using CRISPR/Cas-9 are moving through clinical development and may dramatically alter the future landscape of treatment for HoFH.
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Affiliation(s)
- Archna Bajaj
- Division of Translational Medicine & Human Genetics, University of Pennsylvania
| | - Marina Cuchel
- Division of Translational Medicine & Human Genetics, University of Pennsylvania
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6
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Sniderman AD, Glavinovic T, Thanassoulis G. Key Questions About Familial Hypercholesterolemia: JACC Review Topic of the Week. J Am Coll Cardiol 2022; 79:1023-1031. [PMID: 35272797 DOI: 10.1016/j.jacc.2022.01.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 12/16/2022]
Abstract
Familial hypercholesterolemia (FH) is characterized as a monogenic, autosomal dominant disorder, producing severe hypercholesterolemia within families due to causal variants within genes regulating the low-density lipoprotein receptor pathway. Demonstration of a causal variant is widely accepted as evidence of substantially higher cardiovascular risk. However, recent large-scale population studies challenge this characterization of FH, which appears to account for only a minor portion of those with severe hypercholesterolemia. Moreover, a substantial portion of FH variant positive patients do not have marked hypercholesterolemia. These discordances raise doubt as to how FH should be defined and how the concentration of low-density lipoprotein in plasma is regulated in individuals with and without FH. Moreover, review of the evidence suggests the impact of an FH causal variant on cardiovascular risk may be less than previously accepted and that all patients with severe hypercholesterolemia should be prioritized for therapy and family screening.
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Affiliation(s)
- Allan D Sniderman
- Mike and Valeria Rosenbloom Centre for Cardiovascular Prevention, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada.
| | - Tamara Glavinovic
- Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada
| | - George Thanassoulis
- Mike and Valeria Rosenbloom Centre for Cardiovascular Prevention, Department of Medicine, McGill University Health Centre, Montreal, Quebec, Canada. https://twitter.com/thanassoulisMD
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Ying Q, Chan DC, Barrett PHR, Watts GF. Unravelling lipoprotein metabolism with stable isotopes: tracing the flow. Metabolism 2021; 124:154887. [PMID: 34508741 DOI: 10.1016/j.metabol.2021.154887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/16/2021] [Accepted: 09/01/2021] [Indexed: 12/13/2022]
Abstract
Dysregulated lipoprotein metabolism is a major cause of atherosclerotic cardiovascular disease (ASCVD). Use of stable isotope tracers and compartmental modelling have provided deeper understanding of the mechanisms underlying lipid disorders in patients at high risk of ASCVD, including familial hypercholesterolemia (FH), elevated lipoprotein(a) [Lp(a)] and metabolic syndrome (MetS). In patients with FH, deficiency in low-density lipoprotein (LDL) receptor activity not only impairs the catabolism of LDL, but also induces hepatic overproduction and decreases catabolism of triglyceride-rich lipoproteins (TRLs). Patients with elevated Lp(a) are characterized by increased hepatic secretion of Lp(a) particles. Atherogenic dyslipidemia in MetS patients relates to a combination of overproduction of very-low density lipoprotein-apolipoprotein (apo) B-100, decreased catabolism of apoB-100-containing particles, and increased catabolism of high-density lipoprotein-apoA-I particles, as well as to impaired clearance of TRLs in the postprandial state. Kinetic studies show that weight loss, fish oils, statins and fibrates have complementary modes of action that correct atherogenic dyslipidemia. Defining the kinetic mechanisms of action of proprotein convertase subtilisin/kexin type 9 and angiopoietin-like 3 inhibitors on lipid and lipoprotein mechanism in dyslipidemic subjects will further our understanding of these therapies in decreasing the development of ASCVD. "Everything changes but change itself. Everything flows and nothing remains the same... You cannot step twice into the same river, for other waters and yet others go flowing ever on." Heraclitus (c.535- c. 475 BCE).
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Affiliation(s)
- Qidi Ying
- Medical School, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia
| | - Dick C Chan
- Medical School, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia
| | - P Hugh R Barrett
- Faculty of Medicine and Health, University of New England, Armidale, Australia
| | - Gerald F Watts
- Medical School, Faculty of Health and Medical Sciences, University of Western Australia, Perth, Australia; Lipid Disorders Clinic, Departments of Cardiology and Internal Medicine, Royal Perth Hospital, Perth, Australia.
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8
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Seidah NG. The PCSK9 discovery, an inactive protease with varied functions in hypercholesterolemia, viral infections, and cancer. J Lipid Res 2021; 62:100130. [PMID: 34606887 PMCID: PMC8551645 DOI: 10.1016/j.jlr.2021.100130] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/19/2021] [Accepted: 08/21/2021] [Indexed: 01/06/2023] Open
Abstract
In 2003, the sequences of mammalian proprotein convertase subtilisin/kexin type 9 (PCSK9) were reported. Radiolabeling pulse-chase analyses demonstrated that PCSK9 was synthesized as a precursor (proPCSK9) that undergoes autocatalytic cleavage in the endoplasmic reticulum into PCSK9, which is then secreted as an inactive enzyme in complex with its inhibitory prodomain. Its high mRNA expression in liver hepatocytes and its gene localization on chromosome 1p32, a third locus associated with familial hypercholesterolemia, other than LDLR or APOB, led us to identify three patient families expressing the PCSK9 variants S127R or F216L. Although Pcsk9 and Ldlr were downregulated in mice that were fed a cholesterol-rich diet, PCSK9 overexpression led to the degradation of the LDLR. This led to the demonstration that gain-of-function and loss-of-function variations in PCSK9 modulate its bioactivity, whereby PCSK9 binds the LDLR in a nonenzymatic fashion to induce its degradation in endosomes/lysosomes. PCSK9 was also shown to play major roles in targeting other receptors for degradation, thereby regulating various processes, including hypercholesterolemia and associated atherosclerosis, vascular inflammation, viral infections, and immune checkpoint regulation in cancer. Injectable PCSK9 monoclonal antibody or siRNA is currently used in clinics worldwide to treat hypercholesterolemia and could be combined with current therapies in cancer/metastasis. In this review, we present the critical information that led to the discovery of PCSK9 and its implication in LDL-C metabolism. We further analyze the underlying functional mechanism(s) in the regulation of LDL-C, as well as the evolving novel roles of PCSK9 in both health and disease states.
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Affiliation(s)
- Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Montreal Clinical Research Institute (IRCM, affiliated to the University of Montreal), 110 Pine Ave West, Montreal, QC, H2W 1R7, Canada.
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Duran EK, Pradhan AD. Triglyceride-Rich Lipoprotein Remnants and Cardiovascular Disease. Clin Chem 2021; 67:183-196. [PMID: 33409533 DOI: 10.1093/clinchem/hvaa296] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 10/29/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Triglycerides, cholesterol, and their metabolism are linked due to shared packaging and transport within circulating lipoprotein particles. While a case for a causal role of cholesterol-carrying low-density lipoproteins (LDLs) in atherosclerosis is well made, the body of scientific evidence for a causal role of triglyceride-rich lipoproteins (TRLs) is rapidly growing, with multiple lines of evidence (old and new) providing robust support. CONTENT This review will discuss current perspectives and accumulated evidence that an overabundance of remnant lipoproteins stemming from intravascular remodeling of nascent TRLs-chylomicrons and very low-density lipoproteins (VLDL)-results in a proatherogenic milieu that augments cardiovascular risk. Basic mechanisms of TRL metabolism and clearance will be summarized, assay methods reviewed, and pivotal clinical studies highlighted. SUMMARY Remnant lipoproteins are rendered highly atherogenic by their high cholesterol content, altered apolipoprotein composition, and physicochemical properties. The aggregate findings from multiple lines of evidence suggest that TRL remnants play a central role in residual cardiovascular risk.
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Affiliation(s)
- Edward K Duran
- Cardiovascular Division, University of Minnesota Medical Center, Minneapolis, MN
| | - Aruna D Pradhan
- Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.,Division of Cardiovascular Medicine, VA Boston Medical Center, Boston, MA
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Abstract
PURPOSE OF REVIEW Triglycerides (TGs) are measured as part of routine lipid profiles but their relationship to cardiovascular disease (CVD) risk has been controversial and overshadowed by high-density lipoprotein cholesterol (HDL-C). RECENT FINDINGS Epidemiological studies show a clear relationship of TG-containing lipoproteins including remnant particles with CVD risk with the effect being most clearly demonstrated through the excess risk captured by non-HDL-C compared with low-density lipoprotein-cholesterol (LDL-C). Mendelian randomisation studies show a consistent relationship of gene variants linked to TG metabolism with rates of CVD. Furthermore, meta-analyses of intervention trials with statins and other nonstatin drugs also suggest that reducing TGs is associated with benefits on rates of CVD events. Historical subgroup data from fibrate trials suggest benefits in patients with high TG:HDL ratios but seem to add little to optimized statin therapy. Recent trials with omega-3 fatty acids (specifically eicosapentaenoic acid) have suggested that high-dose formulations in contrast to low dose formulations have benefits on CVD outcomes. SUMMARY Further studies with newer agents are required to determine the place of TG-lowering drugs in therapeutic pathways. Trials with agents such as pemafibrate and vupanorsen may finally answer these questions.
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Affiliation(s)
| | - Anthony S Wierzbicki
- Metabolic Medicine/Chemical Pathology, Guy's & St Thomas Hospitals, London SE1 7EH, UK
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Vergès B, Duvillard L, Pais de Barros JP, Bouillet B, Baillot-Rudoni S, Rouland A, Petit JM, Degrace P, Demizieux L. Liraglutide Increases the Catabolism of Apolipoprotein B100-Containing Lipoproteins in Patients With Type 2 Diabetes and Reduces Proprotein Convertase Subtilisin/Kexin Type 9 Expression. Diabetes Care 2021; 44:1027-1037. [PMID: 33531418 DOI: 10.2337/dc20-1843] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 01/10/2021] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Dyslipidemia observed in type 2 diabetes (T2D) is atherogenic. Important features of diabetic dyslipidemia are increased levels of triglyceride-rich lipoproteins and small dense LDL particles, which all have apolipoprotein B100 (apoB100) as a major apolipoprotein. This prompted us to study the effect of the GLP-1 agonist liraglutide on the metabolism of apoB100-containing lipoproteins. RESEARCH DESIGN AND METHODS We performed an in vivo kinetic study with stable isotopes (L-[1-13C]leucine) in 10 patients with T2D before and after 6 months of treatment with liraglutide (1.2 mg/day). We also evaluated in mice the effect of liraglutide on the expression of genes involved in apoB100-containing lipoprotein clearance. RESULTS In patients with T2D, liraglutide treatment significantly reduced plasma apoB100 (0.93 ± 0.13 vs. 1.09 ± 0.11 g/L, P = 0.011) and fasting triglycerides (1.76 ± 0.37 vs. 2.48 ± 0.69 mmol/L, P = 0.005). The kinetic study showed a significant increase in indirect catabolism of VLDL1-apoB100 (4.11 ± 1.91 vs. 2.96 ± 1.61 pools/day, P = 0.005), VLDL2-apoB100 (5.17 ± 2.53 vs. 2.84 ± 1.65 pools/day, P = 0.008), and IDL-apoB100 (5.27 ± 2.77 vs. 3.74 ± 1.85 pools/day, P = 0.017) and in catabolism of LDL-apoB100 (0.72 ± 0.22 vs. 0.56 ± 0.22 pools/day, P = 0.005). In mice, liraglutide increased lipoprotein lipase (LPL) gene expression and reduced proprotein convertase subtilisin/kexin type 9 (PCSK9), retinol-binding protein 4 (RBP4), and tumor necrosis factor-α (TNF-α) gene expression in adipose tissue and decreased PCSK9 mRNA and increased LDL receptor protein expression in liver. In vitro, liraglutide directly reduced the expression of PCSK9 in the liver. CONCLUSIONS Treatment with liraglutide induces a significant acceleration of the catabolism of triglyceride-rich lipoproteins (VLDL1, VLDL2, IDL) and LDL. Liraglutide modifies the expression of genes involved in apoB100-containing lipoprotein catabolism. These positive effects on lipoprotein metabolism may reduce cardiovascular risk in T2D.
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Affiliation(s)
- Bruno Vergès
- Department of Endocrinology-Diabetology, CHU Dijon, Dijon, France .,INSERM LNC UMR1231, University of Burgundy, Dijon, France
| | - Laurence Duvillard
- INSERM LNC UMR1231, University of Burgundy, Dijon, France.,Department of Biochemistry, CHU Dijon, Dijon, France
| | - Jean Paul Pais de Barros
- INSERM LNC UMR1231, University of Burgundy, Dijon, France.,Lipidomic Analytical Platform, University of Burgundy, Dijon, France
| | - Benjamin Bouillet
- Department of Endocrinology-Diabetology, CHU Dijon, Dijon, France.,INSERM LNC UMR1231, University of Burgundy, Dijon, France
| | | | - Alexia Rouland
- Department of Endocrinology-Diabetology, CHU Dijon, Dijon, France.,INSERM LNC UMR1231, University of Burgundy, Dijon, France
| | - Jean Michel Petit
- Department of Endocrinology-Diabetology, CHU Dijon, Dijon, France.,INSERM LNC UMR1231, University of Burgundy, Dijon, France
| | - Pascal Degrace
- INSERM LNC UMR1231, University of Burgundy, Dijon, France
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Reeskamp LF, Millar JS, Wu L, Jansen H, van Harskamp D, Schierbeek H, Gipe DA, Rader DJ, Dallinga-Thie GM, Hovingh GK, Cuchel M. ANGPTL3 Inhibition With Evinacumab Results in Faster Clearance of IDL and LDL apoB in Patients With Homozygous Familial Hypercholesterolemia-Brief Report. Arterioscler Thromb Vasc Biol 2021; 41:1753-1759. [PMID: 33691480 PMCID: PMC8057526 DOI: 10.1161/atvbaha.120.315204] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Supplemental Digital Content is available in the text. Objective: The mechanism by which evinacumab, a fully human monoclonal antibody directed against ANGPTL3 (angiopoietin-like 3 protein) lowers plasma LDL (low-density lipoprotein) cholesterol levels in patients with homozygous familial hypercholesterolemia is unknown. We investigated apoB (apolipoprotein B) containing lipoprotein kinetic parameters in patients with homozygous familial hypercholesterolemia, before and after treatment with evinacumab. Approach and Results: Four patients with homozygous familial hypercholesterolemia underwent apoB kinetic analyses in 2 centers as part of a substudy of a trial evaluating the efficacy and safety of evinacumab in patients with homozygous familial hypercholesterolemia. The enrichment of apoB with the stable isotope (5,5,5-2H3)-Leucine was measured in VLDL (very LDL), IDL (intermediate-density lipoprotein), and LDL at different time points before and after intravenous administration of 15 mg/kg evinacumab. Evinacumab lowered LDL-cholesterol by 59±2% and increased IDL apoB and LDL apoB fractional catabolic rate in all 4 homozygous familial hypercholesterolemia subjects, by 616±504% and 113±14%, respectively. VLDL-apoB production rate decreased in 2 of the 4 subjects. Conclusions: In this small study, ANGPTL3 inhibition with evinacumab is associated with an increase in the fractional catabolic rate of IDL apoB and LDL apoB, suggesting that evinacumab lowers LDL-cholesterol predominantly by increasing apoB-containing lipoprotein clearance from the circulation. Additional studies are needed to unravel which factors are determinants in this biological pathway. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04722068.
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Affiliation(s)
- Laurens F Reeskamp
- Department of Vascular Medicine (L.F.R., G.K.H.), Amsterdam UMC, location AMC, University of Amsterdam, The Netherlands
| | - John S Millar
- Institute for Diabetes, Obesity, and Metabolism (J.S.M.), Perelman School of Medicine, University of Pennsylvania, Philadelphia.,Division of Translational Medicine and Human Genetics, Department of Medicine (J.S.M., L.W., D.J.R., M.C.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Liya Wu
- Division of Translational Medicine and Human Genetics, Department of Medicine (J.S.M., L.W., D.J.R., M.C.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Hans Jansen
- Department of Experimental Vascular Medicine (H.J.), Amsterdam UMC, location AMC, University of Amsterdam, The Netherlands
| | - Dewi van Harskamp
- Stable Isotope Research Laboratory, Endocrinology, Vrije Universiteit (D.v.H., H.S.), Amsterdam UMC, location AMC, University of Amsterdam, The Netherlands
| | - Henk Schierbeek
- Stable Isotope Research Laboratory, Endocrinology, Vrije Universiteit (D.v.H., H.S.), Amsterdam UMC, location AMC, University of Amsterdam, The Netherlands
| | - Daniel A Gipe
- Regeneron Pharmaceuticals, Inc, Tarrytown, NY (D.A.G.)
| | - Daniel J Rader
- Division of Translational Medicine and Human Genetics, Department of Medicine (J.S.M., L.W., D.J.R., M.C.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | | | - G Kees Hovingh
- Department of Vascular Medicine (L.F.R., G.K.H.), Amsterdam UMC, location AMC, University of Amsterdam, The Netherlands
| | - Marina Cuchel
- Division of Translational Medicine and Human Genetics, Department of Medicine (J.S.M., L.W., D.J.R., M.C.), Perelman School of Medicine, University of Pennsylvania, Philadelphia
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Teixeira da Costa LF. On the possible existence of a liver LDL-ostat, and its malfunctioning in familial hypercholesterolemia. Med Hypotheses 2021; 147:110500. [PMID: 33515861 DOI: 10.1016/j.mehy.2021.110500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 12/29/2020] [Accepted: 01/08/2021] [Indexed: 11/16/2022]
Abstract
The investigation of familial hypercholesterolemia (FH) and its relationship to atherosclerosis has led to enormous scientific and medical progress, including the identification of genetic defects underlying FH, the elucidation of molecular mechanisms crucial for cellular cholesterol homeostasis and the development of current pharmaceutical tools for FH treatment (which are directed at increasing LDL uptake). These successes also led to the establishment of a model centered on cellular rather than whole organism processes, and a view of FH as resulting from a deficiency in LDL uptake. On the other hand, whole organism fluxes of cholesterol (like those of other nutrients) are centered on the liver, LDL (ultimately derived from the liver) is the main cholesterol transporter in plasma, and there is evidence of evolutionary pressure favoring mechanisms to maintain LDL plasma concentrations. Furthermore, the alterations in cellular metabolism observed in FH are consistent with a coordinated response by the liver to increase the levels of plasma LDL, suggesting that a signaling defect (rather than an uptake deficiency) is the fundamental problem underlying hypercholesterolemia - an hypothesis that explains the occurrence of hypercholesterolemia in CESD, despite normal LDL binding and uptake. I therefore propose that the liver contains a mechanism to assess and regulate plasma levels of LDL (an "LDL-ostat"), and that hypercholesterolemia is caused by defects in it. This model has implications for future research directions, and suggests alternative therapeutic approaches, particularly centered on efforts to restore LDL measurement/signaling (rather than its uptake), some of which are in stark contrast to those currently in use.
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Affiliation(s)
- Luís Filipe Teixeira da Costa
- Unit for Cardiac and Cardiovascular Genetics, Department of Medical Genetics, Oslo University Hospital, P.O. Box 4956 Nydalen, 0424 Oslo, Norway.
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14
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Ka J, Jin SW. Zebrafish as an Emerging Model for Dyslipidemia and Associated Diseases. J Lipid Atheroscler 2020; 10:42-56. [PMID: 33537252 PMCID: PMC7838516 DOI: 10.12997/jla.2021.10.1.42] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 11/06/2020] [Accepted: 11/30/2020] [Indexed: 01/03/2023] Open
Abstract
Dyslipidemia related diseases such as hyperlipidemia and atherosclerosis are the leading cause of death in humans. While cellular and molecular basis on the pathophysiology of dyslipidemia has been extensively investigated over decades, we still lack comprehensive understanding on the etiology of dyslipidemia due to the complexity and the innate multimodality of the diseases. While mouse has been the model organism of choice to investigate the pathophysiology of human dyslipidemia, zebrafish, a small freshwater fish which has traditionally used to study vertebrate development, has recently emerged as an alternative model organism. In this review, we will provide comprehensive perspective on zebrafish as a model organism for human dyslipidemia; we will discuss the attributes of zebrafish as a model, and compare the lipid metabolism in zebrafish and humans. In addition, we will summarize current landscape of zebrafish-based dyslipidemia research.
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Affiliation(s)
- Jun Ka
- Cell Logistics Research Center and School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Suk-Won Jin
- Cell Logistics Research Center and School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea.,Yale Cardiovascular Research Center and Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
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15
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Morro B, Doherty MK, Balseiro P, Handeland SO, MacKenzie S, Sveier H, Albalat A. Plasma proteome profiling of freshwater and seawater life stages of rainbow trout (Oncorhynchus mykiss). PLoS One 2020; 15:e0227003. [PMID: 31899766 PMCID: PMC6941806 DOI: 10.1371/journal.pone.0227003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 12/09/2019] [Indexed: 01/18/2023] Open
Abstract
The sea-run phenotype of rainbow trout (Oncorhynchus mykiss), like other anadromous salmonids, present a juvenile stage fully adapted to life in freshwater known as parr. Development in freshwater is followed by the smolt stage, where preadaptations needed for seawater life are developed making fish ready to migrate to the ocean, after which event they become post-smolts. While these three life stages have been studied using a variety of approaches, proteomics has never been used for such purpose. The present study characterised the blood plasma proteome of parr, smolt and post-smolt rainbow trout using a gel electrophoresis liquid chromatography tandem mass spectrometry approach alone or in combination with low-abundant protein enrichment technology (combinatorial peptide ligand library). In total, 1,822 proteins were quantified, 17.95% of them being detected only in plasma post enrichment. Across all life stages, the most abundant proteins were ankyrin-2, DNA primase large subunit, actin, serum albumin, apolipoproteins, hemoglobin subunits, hemopexin-like proteins and complement C3. When comparing the different life stages, 17 proteins involved in mechanisms to cope with hyperosmotic stress and retinal changes, as well as the downregulation of nonessential processes in smolts, were significantly different between parr and smolt samples. On the other hand, 11 proteins related to increased growth in post-smolts, and also related to coping with hyperosmotic stress and to retinal changes, were significantly different between smolt and post-smolt samples. Overall, this study presents a series of proteins with the potential to complement current seawater-readiness assessment tests in rainbow trout, which can be measured non-lethally in an easily accessible biofluid. Furthermore, this study represents a first in-depth characterisation of the rainbow trout blood plasma proteome, having considered three life stages of the fish and used both fractionation alone or in combination with enrichment methods to increase protein detection.
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Affiliation(s)
- Bernat Morro
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, United Kingdom
| | - Mary K. Doherty
- Institute of Health Research and Innovation, Centre for Health Science, University of the Highlands and Islands, Inverness, Scotland, United Kingdom
| | | | | | - Simon MacKenzie
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, United Kingdom
- NORCE AS, Universitetet i Bergen, Bergen, Norway
| | - Harald Sveier
- Lerøy Seafood Group ASA, Universitetet i Bergen, Bergen, Norway
| | - Amaya Albalat
- Institute of Aquaculture, University of Stirling, Stirling, Scotland, United Kingdom
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16
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Packard CJ, Boren J, Taskinen MR. Causes and Consequences of Hypertriglyceridemia. Front Endocrinol (Lausanne) 2020; 11:252. [PMID: 32477261 PMCID: PMC7239992 DOI: 10.3389/fendo.2020.00252] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 04/06/2020] [Indexed: 12/12/2022] Open
Abstract
Elevations in plasma triglyceride are the result of overproduction and impaired clearance of triglyceride-rich lipoproteins-very low-density lipoproteins (VLDL) and chylomicrons. Hypertriglyceridemia is characterized by an accumulation in the circulation of large VLDL-VLDL1-and its lipolytic products, and throughout the VLDL-LDL delipidation cascade perturbations occur that give rise to increased concentrations of remnant lipoproteins and small, dense low-density lipoprotein (LDL). The elevated risk of atherosclerotic cardiovascular disease in hypertriglyceridemia is believed to result from the exposure of the artery wall to these aberrant lipoprotein species. Key regulators of the metabolism of triglyceride-rich lipoproteins have been identified and a number of these are targets for pharmacological intervention. However, a clear picture is yet to emerge as to how to relate triglyceride lowering to reduced risk of atherosclerosis.
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Affiliation(s)
- Chris J. Packard
- Institute of Cardiovascular and Medical Sciences, Glasgow University, Glasgow, United Kingdom
- *Correspondence: Chris J. Packard
| | - Jan Boren
- Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Marja-Riitta Taskinen
- Research Programs Unit, Clinical and Molecular Metabolism, University of Helsinki, Helsinki, Finland
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17
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Delayed postprandial TAG peak after intake of SFA compared with PUFA in subjects with and without familial hypercholesterolaemia: a randomised controlled trial. Br J Nutr 2019; 119:1142-1150. [PMID: 29759104 DOI: 10.1017/s0007114518000673] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Postprandial hypertriacylglycerolaemia is associated with an increased risk of developing CVD. How fat quality influences postprandial lipid response is scarcely explored in subjects with familial hypercholesterolaemia (FH). The aim of this study was to investigate the postprandial response of TAG and lipid sub-classes after consumption of high-fat meals with different fat quality in subjects with FH compared with normolipidaemic controls. A randomised controlled double-blind cross-over study with two meals and two groups was performed. A total of thirteen hypercholesterolaemic subjects with FH who discontinued lipid-lowering treatment 4 weeks before and during the study, and fourteen normolipidaemic controls, were included. Subjects were aged 18-30 years and had a BMI of 18·5-30·0 kg/m2. Each meal consisted of a muffin containing 60 g (70 E%) of fat, either mainly SFA (40 E%) or PUFA (40 E%), eaten in a random order with a wash-out period of 3-5 weeks between the meals. Blood samples were collected at baseline (fasting) and 2, 4 and 6 h after intake of the meals. In both FH and control subjects, the level of TAG and the largest VLDL sub-classes peaked at 2 h after intake of PUFA and at 4 h after intake of SFA. No significant differences were found in TAG levels between meals or between groups (0·25≤P≤0·72). The distinct TAG peaks may reflect differences in the postprandial lipid metabolism after intake of fatty acids with different chain lengths and degrees of saturation. The clinical impact of these findings remains to be determined.
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18
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Kawakami R, Nozato Y, Nakagami H, Ikeda Y, Shimamura M, Yoshida S, Sun J, Kawano T, Takami Y, Noma T, Rakugi H, Minamino T, Morishita R. Development of vaccine for dyslipidemia targeted to a proprotein convertase subtilisin/kexin type 9 (PCSK9) epitope in mice. PLoS One 2018; 13:e0191895. [PMID: 29438441 PMCID: PMC5811007 DOI: 10.1371/journal.pone.0191895] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 01/12/2018] [Indexed: 01/07/2023] Open
Abstract
Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates expression of low-density lipoprotein (LDL) receptors via receptor internalization and subsequent lysosomal degradation. Thus, an anti-PCSK9 antibody is well known as an anti-hyperlipidemia drug. Here, we aimed to develop vaccine for a long-term treatment of dyslipidemia targeted to PCSK9. In This study, we designed a peptide vaccine for mouse PCSK-9, which consisted of short peptides conjugated to keyhole limpet hemocyanin (KLH) as a carrier protein. Vaccines were administered to male apolipoprotein E (ApoE) deficient mice with adjuvants and significantly elicited an antibody response against PCSK9. The PCSK9 vaccines were administered to mice three times in 2-week intervals, and antibody titers and lipoprotein levels were evaluated up to 24 weeks after the first immunization to determine the therapeutic effect. Anti-PCSK9 antibody titers reached peak levels 6 weeks after the first immunization, and theses titers were maintained for up to 24 weeks. Decreased plasma levels of total cholesterol, very low-density lipoprotein (VLDL), and chylomicron (CM) were maintained for up to 24 weeks. Immunized mice exhibited a significant increase in cell-surface LDL receptor expression. Stimulation with KLH, but not PCSK9, induced the production of INF-gamma and interleukin-4 (IL-4), as determined with ELISPOT assays, thus indicating that PCSK9 vaccine did not elicit T-cell activation in our vaccine system. The present anti-PCSK9 vaccine induced long-lasting anti-PCSK9 antibody production and improved lipoprotein profiles. Thus, anti-PCSK9 vaccine could become a new option for the treatment of dyslipidemia as a long-acting therapy in future.
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Affiliation(s)
- Ryo Kawakami
- Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan.,Department of Clinical Gene Therapy, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Yoichi Nozato
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Hironori Nakagami
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Yuka Ikeda
- Department of Clinical Gene Therapy, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Munehisa Shimamura
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Shota Yoshida
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Jiao Sun
- Department of Health Development and Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Tomohiro Kawano
- Department of Neurology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Yoichi Takami
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Takahisa Noma
- Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Hiromi Rakugi
- Department of Geriatric and General Medicine, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
| | - Tetsuo Minamino
- Department of Cardiorenal and Cerebrovascular Medicine, Faculty of Medicine, Kagawa University, Kagawa, Japan
| | - Ryuichi Morishita
- Department of Clinical Gene Therapy, Osaka University Graduate School of Medicine, Suita, Osaka, Japan
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19
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High serum triglyceride concentrations in patients with homozygous familial hypercholesterolemia attenuate the efficacy of lipoprotein apheresis by dextran sulfate adsorption. Atherosclerosis 2018; 270:26-32. [PMID: 29407885 DOI: 10.1016/j.atherosclerosis.2018.01.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/21/2017] [Accepted: 01/11/2018] [Indexed: 12/23/2022]
Abstract
BACKGROUND AND AIMS Maximizing the acute reduction of LDL-cholesterol (C) and lipoprotein (a) (Lp(a)) concentrations in patients with homozygous familial hypercholesterolemia (HoFH) is the main goal of lipoprotein apheresis (LA). The objective of this study was to examine how the pre-LA serum TG concentrations influence the efficacy of LA to acutely reduce LDL-C and Lp(a) concentrations in HoFH patients. METHODS Data from 1761 LA treatments of HoFH patients (n = 10) and compound heterozygous patients (n = 5) collected between 2008 and 2016 were analyzed. These data included the pre- and post-LA concentrations of LDL-C, TGs and Lp(a); volume of filtered plasma; type of LA system used (dextran sulfate adsorption (DSA) or heparin-induced extracorporeal LDL precipitation (HELP)); and interval between treatments. RESULTS A significant association between the pre-LA TG concentrations and acute LA-induced reduction in LDL-C, modified by the type of LA system used, was observed (ppre-LA TG quartile*LA system = .04). Using the DSA system, the acute reduction of the LDL-C concentrations was attenuated by 3.9% when the pre-LA TG concentrations were >2.09 mmol/L vs. ≤0.93 mmol/L (highest vs. lowest quartiles: -59.4% vs. -63.3%, p = .007). Using the HELP system, no significant difference was observed in the reduction of LDL-C between the highest and the lowest quartiles of serum TGs (-65.8% vs. -66.4%, p = .9). No association was observed between pre-LA TG concentrations and acute LA-induced decrease in Lp(a) (p = .2). CONCLUSIONS The efficacy of LA is inversely associated with pre-LA TG concentrations in HoFH patients who used the DSA system instead of the HELP system.
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20
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Reyes-Soffer G, Moon B, Hernandez-Ono A, Dionizovik-Dimanovski M, Dionizovick-Dimanovski M, Jimenez J, Obunike J, Thomas T, Ngai C, Fontanez N, Donovan DS, Karmally W, Holleran S, Ramakrishnan R, Mittleman RS, Ginsberg HN. Complex effects of inhibiting hepatic apolipoprotein B100 synthesis in humans. Sci Transl Med 2016; 8:323ra12. [PMID: 26819195 DOI: 10.1126/scitranslmed.aad2195] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mipomersen is a 20mer antisense oligonucleotide (ASO) that inhibits apolipoprotein B (apoB) synthesis; its low-density lipoprotein (LDL)-lowering effects should therefore result from reduced secretion of very-low-density lipoprotein (VLDL). We enrolled 17 healthy volunteers who received placebo injections weekly for 3 weeks followed by mipomersen weekly for 7 to 9 weeks. Stable isotopes were used after each treatment to determine fractional catabolic rates and production rates of apoB in VLDL, IDL (intermediate-density lipoprotein), and LDL, and of triglycerides in VLDL. Mipomersen significantly reduced apoB in VLDL, IDL, and LDL, which was associated with increases in fractional catabolic rates of VLDL and LDL apoB and reductions in production rates of IDL and LDL apoB. Unexpectedly, the production rates of VLDL apoB and VLDL triglycerides were unaffected. Small interfering RNA-mediated knockdown of apoB expression in human liver cells demonstrated preservation of apoB secretion across a range of apoB synthesis. Titrated ASO knockdown of apoB mRNA in chow-fed mice preserved both apoB and triglyceride secretion. In contrast, titrated ASO knockdown of apoB mRNA in high-fat-fed mice resulted in stepwise reductions in both apoB and triglyceride secretion. Mipomersen lowered all apoB lipoproteins without reducing the production rate of either VLDL apoB or triglyceride. Our human data are consistent with long-standing models of posttranscriptional and posttranslational regulation of apoB secretion and are supported by in vitro and in vivo experiments. Targeting apoB synthesis may lower levels of apoB lipoproteins without necessarily reducing VLDL secretion, thereby lowering the risk of steatosis associated with this therapeutic strategy.
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Affiliation(s)
- Gissette Reyes-Soffer
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA.
| | - Byoung Moon
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Antonio Hernandez-Ono
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | | | | | - Jhonsua Jimenez
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Joseph Obunike
- Biological Sciences Department, New York City College of Technology, 300 Jay Street, Brooklyn, NY 11201, USA
| | - Tiffany Thomas
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Colleen Ngai
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Nelson Fontanez
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Daniel S Donovan
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Wahida Karmally
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Stephen Holleran
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | - Rajasekhar Ramakrishnan
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
| | | | - Henry N Ginsberg
- Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA.
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21
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Imbalanced insulin action in chronic over nutrition: Clinical harm, molecular mechanisms, and a way forward. Atherosclerosis 2016; 247:225-82. [PMID: 26967715 DOI: 10.1016/j.atherosclerosis.2016.02.004] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 12/31/2015] [Accepted: 02/02/2016] [Indexed: 02/08/2023]
Abstract
The growing worldwide prevalence of overnutrition and underexertion threatens the gains that we have made against atherosclerotic cardiovascular disease and other maladies. Chronic overnutrition causes the atherometabolic syndrome, which is a cluster of seemingly unrelated health problems characterized by increased abdominal girth and body-mass index, high fasting and postprandial concentrations of cholesterol- and triglyceride-rich apoB-lipoproteins (C-TRLs), low plasma HDL levels, impaired regulation of plasma glucose concentrations, hypertension, and a significant risk of developing overt type 2 diabetes mellitus (T2DM). In addition, individuals with this syndrome exhibit fatty liver, hypercoagulability, sympathetic overactivity, a gradually rising set-point for body adiposity, a substantially increased risk of atherosclerotic cardiovascular morbidity and mortality, and--crucially--hyperinsulinemia. Many lines of evidence indicate that each component of the atherometabolic syndrome arises, or is worsened by, pathway-selective insulin resistance and responsiveness (SEIRR). Individuals with SEIRR require compensatory hyperinsulinemia to control plasma glucose levels. The result is overdrive of those pathways that remain insulin-responsive, particularly ERK activation and hepatic de-novo lipogenesis (DNL), while carbohydrate regulation deteriorates. The effects are easily summarized: if hyperinsulinemia does something bad in a tissue or organ, that effect remains responsive in the atherometabolic syndrome and T2DM; and if hyperinsulinemia might do something good, that effect becomes resistant. It is a deadly imbalance in insulin action. From the standpoint of human health, it is the worst possible combination of effects. In this review, we discuss the origins of the atherometabolic syndrome in our historically unprecedented environment that only recently has become full of poorly satiating calories and incessant enticements to sit. Data are examined that indicate the magnitude of daily caloric imbalance that causes obesity. We also cover key aspects of healthy, balanced insulin action in liver, endothelium, brain, and elsewhere. Recent insights into the molecular basis and pathophysiologic harm from SEIRR in these organs are discussed. Importantly, a newly discovered oxide transport chain functions as the master regulator of the balance amongst different limbs of the insulin signaling cascade. This oxide transport chain--abbreviated 'NSAPP' after its five major proteins--fails to function properly during chronic overnutrition, resulting in this harmful pattern of SEIRR. We also review the origins of widespread, chronic overnutrition. Despite its apparent complexity, one factor stands out. A sophisticated junk food industry, aided by subsidies from willing governments, has devoted years of careful effort to promote overeating through the creation of a new class of food and drink that is low- or no-cost to the consumer, convenient, savory, calorically dense, yet weakly satiating. It is past time for the rest of us to overcome these foes of good health and solve this man-made epidemic.
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22
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Tada H, Kawashiri MA, Yoshida T, Teramoto R, Nohara A, Konno T, Inazu A, Mabuchi H, Yamagishi M, Hayashi K. Lipoprotein(a) in Familial Hypercholesterolemia With Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Gain-of-Function Mutations. Circ J 2015; 80:512-8. [PMID: 26632531 DOI: 10.1253/circj.cj-15-0999] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND It has been shown that serum lipoprotein(a) [Lp(a)] is elevated in familial hypercholesterolemia (FH) with mutation(s) of the LDL receptor (LDLR) gene. However, few data exist regarding Lp(a) levels in FH with gain-of-function mutations of the PCSK9 gene. METHODS AND RESULTS We evaluated 42 mutation-determined heterozygous FH patients with aPCSK9gain-of-function mutation (FH-PCSK9, mean age 52, mean LDL-C 235 mg/dl), 198 mutation-determined heterozygous FH patients with aLDLRmutation (FH-LDLR, mean age 44, mean LDL-C 217 mg/dl), and 4,015 controls (CONTROL, mean age 56, mean LDL-C 109 mg/dl). We assessed their Lp(a), total cholesterol, triglycerides, HDL-C, LDL-C, use of statins, presence of hypertension, diabetes, chronic kidney disease, smoking, body mass index (BMI) and coronary artery disease (CAD). Multiple regression analysis showed that HDL-C, use of statins, presence of hypertension, smoking, BMI, and Lp(a) were independently associated with the presence of CAD. Under these conditions, the serum levels of Lp(a) in patients with FH were significantly higher than those of the CONTROL group regardless of their causative genes, among the groups propensity score-matched (median Lp(a) 12.6 mg/dl [IQR:9.4-33.9], 21.1 mg/dl [IQR:11.7-34.9], and 5.0 mg/dl [IQR:2.7-8.1] in the FH-LDLR, FH-PCSK9, and CONTROL groups, respectively, P=0.002 for FH-LDLR vs. CONTROL, P=0.002 for FH-PCSK9 vs. CONTROL). CONCLUSIONS These data demonstrate that serum Lp(a) is elevated in patients with FH caused by PCSK9 gain-of-function mutations to the same level as that in FH caused by LDLR mutations.
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Affiliation(s)
- Hayato Tada
- Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine
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23
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Ahmad Z, Khera A. The role of microsomal triglyceride transfer protein inhibitors in the treatment of patients with familial hypercholesterolemia: risks, benefits, and management. Curr Atheroscler Rep 2015; 17:469. [PMID: 25408543 DOI: 10.1007/s11883-014-0469-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Statins fail to adequately reduce low-density lipoprotein-cholesterol (LDL-C) in patients with homozygous familial hypercholesterolemia, requiring these patients to undergo weekly or bi-weekly sessions of LDL apheresis. Although efficacious, LDL apheresis is an invasive procedure with high cost and low availability, and additional options, such as inhibitors of microsomal transfer protein (MTP), may have benefit. Inhibition of MTP reduces levels of circulating cholesterol and triglycerides by preventing the formation of very-low-density lipoprotein and chylomicrons. LDL-C levels decrease by as much as 50%. Unfortunately, adverse effects-the most common of which are gastrointestinal-related and hepatic lipid accumulation-limit broader use of the drug. Furthermore, the cardiovascular benefit of MTP inhibition remains unclear. However, MTP inhibition offers a viable additional lipid-lowering option for patients with homozygous familial hypercholesterolemia.
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Affiliation(s)
- Zahid Ahmad
- Department of Internal Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA,
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24
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Millar JS, Reyes-Soffer G, Jumes P, Dunbar RL, deGoma EM, Baer AL, Karmally W, Donovan DS, Rafeek H, Pollan L, Tohyama J, Johnson-Levonas AO, Wagner JA, Holleran S, Obunike J, Liu Y, Ramakrishnan R, Lassman ME, Gutstein DE, Ginsberg HN, Rader DJ. Anacetrapib lowers LDL by increasing ApoB clearance in mildly hypercholesterolemic subjects. J Clin Invest 2015; 125:2510-22. [PMID: 25961461 DOI: 10.1172/jci80025] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 04/13/2015] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Individuals treated with the cholesteryl ester transfer protein (CETP) inhibitor anacetrapib exhibit a reduction in both LDL cholesterol and apolipoprotein B (ApoB) in response to monotherapy or combination therapy with a statin. It is not clear how anacetrapib exerts these effects; therefore, the goal of this study was to determine the kinetic mechanism responsible for the reduction in LDL and ApoB in response to anacetrapib. METHODS We performed a trial of the effects of anacetrapib on ApoB kinetics. Mildly hypercholesterolemic subjects were randomized to background treatment of either placebo (n = 10) or 20 mg atorvastatin (ATV) (n = 29) for 4 weeks. All subjects then added 100 mg anacetrapib to background treatment for 8 weeks. Following each study period, subjects underwent a metabolic study to determine the LDL-ApoB-100 and proprotein convertase subtilisin/kexin type 9 (PCSK9) production rate (PR) and fractional catabolic rate (FCR). RESULTS Anacetrapib markedly reduced the LDL-ApoB-100 pool size (PS) in both the placebo and ATV groups. These changes in PS resulted from substantial increases in LDL-ApoB-100 FCRs in both groups. Anacetrapib had no effect on LDL-ApoB-100 PRs in either treatment group. Moreover, there were no changes in the PCSK9 PS, FCR, or PR in either group. Anacetrapib treatment was associated with considerable increases in the LDL triglyceride/cholesterol ratio and LDL size by NMR. CONCLUSION These data indicate that anacetrapib, given alone or in combination with a statin, reduces LDL-ApoB-100 levels by increasing the rate of ApoB-100 fractional clearance. TRIAL REGISTRATION ClinicalTrials.gov NCT00990808. FUNDING Merck & Co. Inc., Kenilworth, New Jersey, USA. Additional support for instrumentation was obtained from the National Center for Advancing Translational Sciences (UL1TR000003 and UL1TR000040).
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Lipoprotein metabolism in familial hypercholesterolemia: Serial assessment using a one-step ultracentrifugation method. Pract Lab Med 2015; 1:22-27. [PMID: 28932795 PMCID: PMC5597709 DOI: 10.1016/j.plabm.2015.03.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Revised: 02/27/2015] [Accepted: 03/02/2015] [Indexed: 11/21/2022] Open
Abstract
Objectives It is well known that familial hypercholesterolemia (FH) is a common inherited disorder that can markedly elevate the level of plasma LDL cholesterol. However, little data exists regarding the clinical impact of the plasma triglyceride (TG)-rich lipoprotein fraction, including VLDL and IDL, in FH. Thus, we assessed the hypothesis that the mutations in the LDL receptor modulate lipoprotein metabolism other than the LDL fraction. Design and methods We investigated plasma lipoprotein with a one-step ultracentrifugation method for 146 controls (mean age=61.4±17.1 yr, mean LDL cholesterol=92.7±61.2 mg/dl), 213 heterozygous mutation-determined FH subjects (mean age=46.0±18.0 yr, mean LDL cholesterol=225.1±61.2 mg/dl), and 16 homozygous/compound heterozygous mutation-determined FH subjects (mean age=26.9±17.1 yr, mean LDL cholesterol=428.6±86.1 mg/dl). In addition, we evaluated cholesterol/TG ratio in each lipoprotein fraction separated by ultracentrifugation. Results In addition to total cholesterol and LDL cholesterol levels, VLDL cholesterol (19.5±10.4, 25.2±19.3, 29.5±21.4 mg/dl, respectively) and IDL cholesterol (8.3±3.7, 16.8±11.5, 40.0±37.3 mg/dl, respectively) exhibited a tri-model distribution according to their status in LDL receptor mutation(s). Moreover, the ratios of cholesterol/TG of each lipoprotein fraction increased significantly in heterozygous FH and homozygous/compound heterozygous FH groups, compared with that of controls, suggesting that the abnormality in LDL receptor modulates the quality as well as the quantity of each lipoprotein fraction. Conclusions Our results indicate that cholesterol in TG-rich lipoproteins, including VLDL and IDL, are significantly higher in FH subjects, revealing a tri-modal distribution according to the number of LDL receptor mutations. TG-rich lipoproteins are elevated in FH subjects. Such lipoproteins reveal tri-modal distribution according to the number of mutations. One-step ultracentrifugation is useful to assess lipoprotein abnormalities in FH.
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From Human-Induced Pluripotent Stem Cells to Liver Disease Modeling: A Focus on Dyslipidemia. CURRENT PATHOBIOLOGY REPORTS 2015. [DOI: 10.1007/s40139-015-0067-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Mipomersen preferentially reduces small low-density lipoprotein particle number in patients with hypercholesterolemia. J Clin Lipidol 2014; 9:201-9. [PMID: 25911076 DOI: 10.1016/j.jacl.2014.12.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/02/2014] [Accepted: 12/10/2014] [Indexed: 11/20/2022]
Abstract
BACKGROUND Because of variability in lipoprotein cholesterol content, low-density lipoprotein (LDL) cholesterol frequently underrepresents or overrepresents the number of LDL particles. Mipomersen is an antisense oligonucleotide that reduces hepatic production of apolipoprotein B-100, the sole apolipoprotein of LDL. OBJECTIVE To characterize the effects of mipomersen on lipoprotein particle numbers as well as subclass distribution using nuclear magnetic resonance (NMR) spectroscopy. METHODS We compared the tertiary results for the direct measurement of LDL particle numbers by NMR among 4 placebo-controlled, phase 3 studies of mipomersen that had similar study designs but different patient populations: homozygous familial hypercholesterolemia (HoFH), severe hypercholesterolemia, heterozygous familial hypercholesterolemia with established coronary artery disease, or hypercholesterolemia with high risk for coronary heart disease (HC-CHD). RESULTS HoFH patients had the highest median total LDL particles at baseline compared with HC-CHD patients, who had the lowest. At baseline, the HoFH population uniquely had a greater mean percentage of large LDL particles (placebo, 60.2%; mipomersen, 54.9%) compared with small LDL particles (placebo, 33.1%; mipomersen, 38.9%). In all 4 studies, mipomersen was associated with greater reductions from baseline in the concentrations of small LDL particles compared with those of large LDL particles, and both total LDL particles and small LDL particles were statistically significantly reduced. CONCLUSIONS Mipomersen consistently reduced all LDL particle numbers and preferentially reduced the concentration of small LDL particles in all 4 phase 3 studies.
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Sirtori CR, Pavanello C, Bertolini S. Microsomal transfer protein (MTP) inhibition-a novel approach to the treatment of homozygous hypercholesterolemia. Ann Med 2014; 46:464-74. [PMID: 24987866 DOI: 10.3109/07853890.2014.931100] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Homozygous familial hypercholesterolemia (HoFH) represents the most severe lipoprotein disorder, generally attributable to mutation(s) of the low-density lipoprotein receptor (LDL-R), i.e. autosomal dominant hypercholesterolemia type 1 (ADH1). Much lower percentages are due to alterations of apolipoprotein B (ADH2), or gain-of-function mutations of proprotein convertase subtilisin/kexin type 9 (PCSK9) (ADH3). In certain geographical areas a significant number of patients may be affected by an autosomal recessive hypercholesterolemia (ARH). Mutations may be also combined (two mutations of the same gene, compound heterozygosity), or two in different genes (double heterozygosity). Among the most innovative therapeutic approaches made available recently, inhibitors of the microsomal transfer protein (MTP) system have shown a high clinical potential. MTP plays a critical role in the assembly/secretion of very-low-density lipoproteins (VLDL), and its absence leads to apo B deficiency. MTP antagonists dramatically lower LDL-cholesterol (LDL-C) in animals, although a reported increase of liver fat delayed their clinical development. Lomitapide, the best-studied MTP inhibitor, reduces LDL-C by 50% or more in HoFH patients, with modest, reversible, liver steatosis. Recent US approval has confirmed an acceptable tolerability, provided patients adhere to a strictly low-fat regimen. There are no clinical data on atherosclerosis reduction/regression, but animal models provide encouraging results.
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Vergès B, Duvillard L, Lagrost L, Vachoux C, Garret C, Bouyer K, Courtney M, Pomié C, Burcelin R. Changes in lipoprotein kinetics associated with type 2 diabetes affect the distribution of lipopolysaccharides among lipoproteins. J Clin Endocrinol Metab 2014; 99:E1245-53. [PMID: 24694333 DOI: 10.1210/jc.2013-3463] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Lipopolysaccharides (LPSs) are inflammatory components of the outer membrane of Gram-negative bacteria and, in plasma, are mostly associated with lipoproteins. This association is thought to promote their catabolism while reducing their proinflammatory effects. OBJECTIVES Our aim was to determine the impact of lipoprotein kinetics on plasma LPS distribution and how it may affect patients with type 2 diabetes mellitus (T2DM). DESIGN We performed a kinetic study in 30 individuals (16 T2DM patients, 14 controls) and analyzed the impact of changes in lipoprotein kinetics on LPS distribution among lipoproteins. RESULTS Plasma LPS levels in T2DM patients were not different from those in controls, but LPS distribution in the two groups was different. Patients with T2DM had higher LPS-very low-density lipoprotein (VLDL; 31% ± 7% vs 22% ± 11%, P = .002), LPS-high-density lipoprotein (HDL; 29% ± 9% vs 19% ± 10%, P = .015), free (nonlipoprotein bound) LPS (10% ± 4% vs 7% ± 4%, P = .043) and lower LPS-low-density lipoprotein (LDL; 30% ± 13% vs 52% ± 16%, P = .001). In multivariable analysis, VLDL-LPS was associated with HDL-LPS (P < .0001); LDL-LPS was associated with VLDL-LPS (P = .004), and VLDL apolipoprotein (apo) B100 catabolism (P = .002); HDL-LPS was associated with free LPS (P < .0001) and VLDL-LPS (P = .033); free LPS was associated with HDL-LPS (P < .0001). In a patient featuring a dramatic decrease in VLDL catabolism due to apoA-V mutation, LDL-LPS was severely decreased (0.044 EU/mL vs 0.788 EU/mL in controls). The difference between T2DM patients and controls for LDL-LPS fraction was no longer significant after controlling for VLDL apoB100 total fractional catabolic rate. CONCLUSIONS Our data suggest that in humans, free LPS transfers first to HDL and then to VLDL, whereas the LPS-bound LDL fraction is mainly derived from VLDL catabolism; the latter may hence represent a LPS catabolic pathway. T2DM patients show lower LDL-LPS secondary to reduced VLDL catabolism, which may represent an impaired catabolic pathway.
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Affiliation(s)
- Bruno Vergès
- Department of Endocrinology-Diabetology (B.V.), University-Hospital, and INSERM CRI 866 (B.V., L.D., L.L.), Medicine University, 21000 Dijon, France; INSERM Unité 1048 (C.V., C.G., C.P., R.B.), Institut de Recherche sur les Maladies Métaboliques et Cardiovasculaires de Rangueil (I2MC), 31432 Toulouse, France; and VAIOMER SAS (K.B., M.C.), 31670 Labège, France
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Page MM, Bell DA, Hooper AJ, Watts GF, Burnett JR. Lipoprotein apheresis and new therapies for severe familial hypercholesterolemia in adults and children. Best Pract Res Clin Endocrinol Metab 2014; 28:387-403. [PMID: 24840266 DOI: 10.1016/j.beem.2013.10.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Familial hypercholesterolemia (FH), the most common and severe monogenic form of hypercholesterolemia, is an autosomal co-dominant disease characterized by an increased plasma low density lipoprotein (LDL)-cholesterol concentration and premature coronary heart disease (CHD). The clinical phenotype depends on the gene involved and severity of mutation (or mutations) present. Patients with homozygous or compound heterozygous FH have severe hypercholesterolemia (LDL-cholesterol >13 mmol/L) due to a gene dosing effect and without treatment have accelerated atherosclerotic CHD from birth, and frequently die of CHD before age 30. Cholesterol-lowering therapies have been shown to reduce both mortality and major adverse cardiovascular events in individuals with FH. Lipoprotein apheresis concomitant with lipid-lowering therapy is the treatment of choice for homozygous FH. This article describes the rationale and role of lipoprotein apheresis in the treatment of severe FH and outlines the recent advances in new pharmacotherapies for this condition.
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Affiliation(s)
- Michael M Page
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Damon A Bell
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - Amanda J Hooper
- Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia; School of Pathology & Laboratory Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Gerald F Watts
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia
| | - John R Burnett
- Lipid Disorders Clinic, Department of Internal Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; Department of Clinical Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia; School of Medicine & Pharmacology, University of Western Australia, Perth, Western Australia, Australia.
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Lassman ME, McAvoy T, Lee AYH, Chappell D, Wong O, Zhou H, Reyes-Soffer G, Ginsberg HN, Millar JS, Rader DJ, Gutstein DE, Laterza O. Practical immunoaffinity-enrichment LC-MS for measuring protein kinetics of low-abundance proteins. Clin Chem 2014; 60:1217-24. [PMID: 24751376 DOI: 10.1373/clinchem.2014.222455] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND For a more complete understanding of pharmacodynamic, metabolic, and pathophysiologic effects, protein kinetics, such as production rate and fractional catabolic rate, can offer substantially more information than protein concentration alone. Kinetic experiments with stable isotope tracers typically require laborious sample preparation and are most often used for studying abundant proteins. Here we describe a practical methodology for measuring isotope enrichment into low-abundance proteins that uses an automated procedure and immunoaffinity enrichment (IA) with LC-MS. Low-abundance plasma proteins cholesteryl ester transfer protein (CETP) and proprotein convertase subtilisin/kexin type 9 (PCSK9) were studied as examples. METHODS Human participants (n = 39) were infused with [(2)H(3)]leucine, and blood samples were collected at multiple time points. Sample preparation and analysis were automated and multiplexed to increase throughput. Proteins were concentrated from plasma by use of IA and digested with trypsin to yield proteotypic peptides that were analyzed by microflow chromatography-mass spectrometry to measure isotope enrichment. RESULTS The IA procedure was optimized to provide the greatest signal intensity. Use of a gel-free method increased throughput while increasing the signal. The intra- and interassay CVs were <15% at all isotope enrichment levels studied. More than 1400 samples were analyzed in <3 weeks without the need for instrument stoppages or user interventions. CONCLUSIONS The use of automated gel-free methods to multiplex the measurement of isotope enrichment was applied to the low-abundance proteins CETP and PCSK9.
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Affiliation(s)
| | | | | | | | | | | | | | - Henry N Ginsberg
- Molecular Biomarkers and Diagnostics, Molecular Biomarkers-PPDM, and Clinical Pharmacology, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Whitehouse Station, NJ; Columbia University Medical Center, New York, NY; Division of Translational Medicine and Human Genetics, University of Pennsylvania, Philadelphia, PA
| | - John S Millar
- Division of Translational Medicine and Human Genetics, University of Pennsylvania, Philadelphia, PA
| | - Daniel J Rader
- Division of Translational Medicine and Human Genetics, University of Pennsylvania, Philadelphia, PA
| | - David E Gutstein
- Clinical Pharmacology, Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Whitehouse Station, NJ
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Sniderman AD, Tsimikas S, Fazio S. The severe hypercholesterolemia phenotype: clinical diagnosis, management, and emerging therapies. J Am Coll Cardiol 2014; 63:1935-47. [PMID: 24632267 DOI: 10.1016/j.jacc.2014.01.060] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 01/05/2014] [Accepted: 01/07/2014] [Indexed: 10/25/2022]
Abstract
The severe hypercholesterolemia phenotype includes all patients with marked elevation of low-density lipoprotein cholesterol (LDL-C) levels. The most common cause is autosomal dominant hypercholesterolemia, an inherited disorder caused by mutations either in LDL receptor, apolipoprotein B (APOB), or proprotein convertase subtilisin kexin type 9 (PCSK9) genes. However, it is now known that many subjects with severe inherited hypercholesterolemia have no defects in these genes. These cases are caused either by mutations in genes yet to be identified or are consequences of polygenic, epigenetic, or acquired defects. Because the clinical consequences of extreme hypercholesterolemia are the same no matter the cause, the focus should be on the identification of subjects with severe hypercholesterolemia, followed by phenotypic screening of family members. Genetic screening is not necessary to diagnose or initiate treatment for the severe hypercholesterolemia phenotype. Management of severe hypercholesterolemia is based on risk factor modification and use of multiple lipid-lowering medications. Lipoprotein apheresis is indicated for coronary artery disease (CAD) patients taking maximally tolerated therapy and with LDL-C levels >200 mg/dl (>300 mg/dl if without CAD). A microsomal triglyceride transfer protein inhibitor and an antisense oligonucleotide against APOB have recently been approved for use in subjects with clinically diagnosed homozygous familial hypercholesterolemia. PCSK9 inhibitors, currently in phase II and III trials, lower LDL-C up to an additional 70% in the setting of maximally tolerated medical therapy and have the potential to reduce LDL-C to <70 mg/dl in most patients. Early identification of affected individuals and aggressive treatment should significantly reduce the burden of cardiovascular disease in society.
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Affiliation(s)
- Allan D Sniderman
- Division of Cardiology, Department of Medicine, Royal Victoria Hospital, McGill University Health Centre, Montreal, Quebec, Canada.
| | - Sotirios Tsimikas
- Department of Medicine, University of California San Diego, La Jolla, California.
| | - Sergio Fazio
- Section of Cardiovascular Disease Prevention, Division of Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
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The extended abnormalities in lipoprotein metabolism in familial hypercholesterolemia: Developing a new framework for future therapies. Int J Cardiol 2013; 168:1811-8. [DOI: 10.1016/j.ijcard.2013.06.069] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 05/06/2013] [Accepted: 06/30/2013] [Indexed: 02/04/2023]
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Zhou H, Castro-Perez J, Lassman ME, Thomas T, Li W, McLaughlin T, Dan X, Jumes P, Wagner JA, Gutstein DE, Hubbard BK, Rader DJ, Millar JS, Ginsberg HN, Reyes-Soffer G, Cleary M, Previs SF, Roddy TP. Measurement of apo(a) kinetics in human subjects using a microfluidic device with tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:1294-302. [PMID: 23681806 PMCID: PMC4944116 DOI: 10.1002/rcm.6572] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 02/20/2013] [Accepted: 03/14/2013] [Indexed: 05/15/2023]
Abstract
RATIONALE Apolipoprotein(a) [apo(a)] is the defining protein component of lipoprotein(a) [Lp(a)], an independent risk factor for cardiovascular disease. The regulation of Lp(a) levels in blood is poorly understood in part due to technical challenges in measuring Lp(a) kinetics. Improvements in the ability to readily and reliably measure the kinetics of apo(a) using a stable isotope labeled tracer is expected to facilitate studies of the role of Lp(a) in cardiovascular disease. Since investigators typically determine the isotopic labeling of protein-bound amino acids following acid-catalyzed hydrolysis of a protein of interest [e.g., apo(a)], studies of protein synthesis require extensive protein purification which limits throughput and often requires large sample volumes. We aimed to develop a rapid and efficient method for studying apo(a) kinetics that is suitable for use in studies involving human subjects. METHODS Microfluidic device and tandem mass spectrometry were used to quantify the incorporation of [(2)H3]-leucine tracer into protein-derived peptides. RESULTS We demonstrated that it is feasible to quantify the incorporation of [(2)H3]-leucine tracer into a proteolytic peptide from the non-kringle repeat region of apo(a) in human subjects. Specific attention was directed toward optimizing the multiple reaction monitoring (MRM) transitions, mass spectrometer settings, and chromatography (i.e., critical parameters that affect the sensitivity and reproducibility of isotopic enrichment measurements). The results demonstrated significant advantages with the use of a microfluidic device technology for studying apo(a) kinetics, including enhanced sensitivity relative to conventional micro-flow chromatography, a virtually drift-free elution profile, and a stable and robust electrospray. CONCLUSIONS The technological advances described herein enabled the implementation of a novel method for studying the kinetics of apo(a) in human subjects infused with [(2)H3]-leucine.
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Affiliation(s)
- Haihong Zhou
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Jose Castro-Perez
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Michael E. Lassman
- Clinical Development Laboratory, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | | | - Wenyu Li
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Theresa McLaughlin
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Xie Dan
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Patricia Jumes
- Clinical Pharmacology, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - John A. Wagner
- Clinical Pharmacology, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - David E. Gutstein
- Clinical Pharmacology, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Brian K. Hubbard
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Daniel J. Rader
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John S. Millar
- Division of Translational Medicine and Human Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - Michele Cleary
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
| | - Stephen F. Previs
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
- Correspondence to: S. F. Previs, Molecular Biomarkers, Merck Sharp & Dohme Corp., 2015 Galloping Hill Road, Kenilworth, NJ 07033, USA.
| | - Thomas P. Roddy
- Molecular Biomarkers-PPDM, Merck Sharp & Dohme Corp., Whitehouse Station, NJ, USA
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Schwaiger JP, Nakada Y, Berberich R, Ikewaki K, Dieplinger B, Zitt E, Neyer U, Salmhofer H, Kronenberg F, Koenig P, Dieplinger H. Lipoprotein kinetics in male hemodialysis patients treated with atorvastatin. Clin J Am Soc Nephrol 2013; 8:1319-26. [PMID: 23599405 DOI: 10.2215/cjn.10881012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES In vivo metabolism of atherogenic apolipoprotein B (apoB)-containing lipoproteins is severely impaired in patients undergoing hemodialysis (HD), resulting in markedly prolonged residence times of these particles. It is unclear whether treatment with statins improves LDL kinetics in HD patients as is known for the general population. Therefore, this kinetic study assessed apoB-containing lipoproteins in these patients. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Kinetic measures were analyzed with stable-isotope technology in six men undergoing HD before and after 3 months of daily administration of 10 mg of atorvastatin. Patients were 18-65 years of age, had LDL cholesterol levels between 90 and 200 mg/dl, and had been treated with HD for >6 months. They consumed a standardized isocaloric diet for 3 days before analysis. Fractional catabolic rates (FCRs) and production rates of very-low-density lipoprotein (VLDL)-apoB, intermediate-density lipoprotein-apoB, and LDL-apoB were determined using multicompartment modeling after plasma lipoprotein separation, precipitation of apoB, and determination of tracer-to-tracee ratios using mass spectrometry. RESULTS Plasma concentrations of VLDL- and LDL-apoB were significantly lower (mean ± SD, 7.77±2.62 versus 11.27±6.15 mg/dl, P<0.05; 56.9±23.9 versus 84.0±21.1 mg/dl, P=0.03) and their FCRs were significantly higher (7.20±3.08 versus 5.20±2.98 days(-1), P<0.05; 0.851±0.772 versus 0.446±0.232 days(-1), P<0.05) after 3 months of atorvastatin treatment. Accordingly, the residence times in plasma of VLDL- and LDL-apoB were significantly lower after treatment (0.14 versus 0.19 day and 1.2 versus 2.2 days, respectively). CONCLUSION Lower plasma concentrations and improved kinetics of atherogenic lipoproteins were observed in HD patients after administration of low-dose atorvastatin.
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Affiliation(s)
- Johannes P Schwaiger
- Division of Genetic Epidemiology, Department of Medical Genetics and Molecular Pharmacology, Innsbruck Medical University, Innsbruck, Austria
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Cayo MA, Cai J, DeLaForest A, Noto FK, Nagaoka M, Clark BS, Collery RF, Si-Tayeb K, Duncan SA. JD induced pluripotent stem cell-derived hepatocytes faithfully recapitulate the pathophysiology of familial hypercholesterolemia. Hepatology 2012; 56:2163-71. [PMID: 22653811 PMCID: PMC3900031 DOI: 10.1002/hep.25871] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 05/24/2012] [Indexed: 12/14/2022]
Abstract
UNLABELLED Elevated levels of low-density lipoprotein cholesterol (LDL-C) in plasma are a major contributor to cardiovascular disease, which is the leading cause of death worldwide. Genome-wide association studies (GWAS) have identified 95 loci that associate with control of lipid/cholesterol metabolism. Although GWAS results are highly provocative, direct analyses of the contribution of specific allelic variations in regulating LDL-C has been challenging due to the difficulty in accessing appropriate cells from affected patients. The primary cell type responsible for controlling cholesterol and lipid flux is the hepatocyte. Recently, we have shown that cells with hepatocyte characteristics can be generated from human induced pluripotent stem cells (iPSCs). This finding raises the possibility of using patient-specific iPSC-derived hepatocytes to study the functional contribution of GWAS loci in regulating lipid metabolism. To test the validity of this approach, we produced iPSCs from JD a patient with mutations in the low-density lipoprotein receptor (LDLR) gene that result in familial hypercholesterolemia (FH). We demonstrate that (1) hepatocytes can be efficiently generated from FH iPSCs; (2) in contrast to control cells, FH iPSC-derived hepatocytes are deficient in LDL-C uptake; (3) control but not FH iPSC-derived hepatocytes increase LDL uptake in response to lovastatin; and (4) FH iPSC-derived hepatocytes display a marked elevation in secretion of lipidated apolipoprotein B-100. CONCLUSION Cumulatively, these findings demonstrate that FH iPSC-derived hepatocytes recapitulate the complex pathophysiology of FH in culture. These results also establish that patient-specific iPSC-derived hepatocytes could be used to definitively determine the functional contribution of allelic variation in regulating lipid and cholesterol metabolism and could potentially provide a platform for the identification of novel treatments of cardiovascular disease. (HEPATOLOGY 2012).
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Bell DA, Hooper AJ, Watts GF, Burnett JR. Mipomersen and other therapies for the treatment of severe familial hypercholesterolemia. Vasc Health Risk Manag 2012; 8:651-9. [PMID: 23226021 PMCID: PMC3513909 DOI: 10.2147/vhrm.s28581] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Familial hypercholesterolemia (FH) is an autosomal dominant condition with a population prevalence of one in 300–500 (heterozygous) that is characterized by high levels of low-density lipoprotein (LDL) cholesterol, tendon xanthomata, and premature atherosclerosis and coronary heart disease (CHD). FH is caused mainly by mutations in the LDLR gene. However, mutations in other genes including APOB and PCSK9, can give rise to a similar phenotype. Homozygous FH with an estimated prevalence of one in a million is associated with severe hypercholesterolemia with accelerated atherosclerotic CHD in childhood and without treatment, death usually occurs before the age of 30 years. Current approaches for the treatment of homozygous FH include statin-based lipid-lowering therapies and LDL apheresis. Mipomersen is a second-generation antisense oligonucleotide (ASO) targeted to human apolipoprotein B (apoB)-100. This review provides an overview of the pathophysiology and current treatment options for familial hypercholesterolemia and describes novel therapeutic strategies focusing on mipomersen, an antisense apoB synthesis inhibitor. Mipomersen is distributed mainly to the liver where it silences apoB mRNA, thereby reducing hepatic apoB-100 and giving rise to reductions in plasma total cholesterol, LDL-cholesterol, and apoB concentrations in a dose-and time-dependent manner. Mipomersen has been shown to decrease apoB, LDL-cholesterol and lipoprotein(a) in patients with heterozygous and homozygous FH on maximally tolerated lipid-lowering therapy. The short-term efficacy and safety of mipomersen has been established, however, injection site reactions are common and concern exists regarding the long-term potential for hepatic steatosis with this ASO. In summary, mipomersen given alone or in combination with standard lipid-lowering medications shows promise as an adjunct therapy in patients with homozygous or refractory heterozygous FH at high risk of atherosclerotic CHD, who are not at target or are intolerant of statins.
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Affiliation(s)
- Damon A Bell
- Department of Core Clinical Pathology and Biochemistry, PathWest Laboratory Medicine, Royal Perth Hospital, Perth, Western Australia, Australia
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Vergès B, Guiu B, Cercueil JP, Duvillard L, Robin I, Buffier P, Bouillet B, Aho S, Brindisi MC, Petit JM. Retinol-binding protein 4 is an independent factor associated with triglycerides and a determinant of very low-density lipoprotein-apolipoprotein B100 catabolism in type 2 diabetes mellitus. Arterioscler Thromb Vasc Biol 2012; 32:3050-7. [PMID: 23087360 DOI: 10.1161/atvbaha.112.255190] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Retinol-binding protein 4 (rbp4) is an adipokine secreted by adipocytes and liver, whose levels are elevated in type 2 diabetes mellitus (T2DM). Plasma levels of rbp4 and triglycerides are strongly correlated in T2DM. However, we do not know whether this association is direct or indirect via liver fat content, and the link between rbp4 and triglyceride metabolism remains unknown. METHODS AND RESULTS Liver fat measurement by proton spectroscopy was performed in 221 patients with T2DM, and an in vivo kinetic study with stable isotopes was carried out in 14 patients with T2DM. In multivariate analysis, triglycerides were associated positively with rbp4 (β=0.273, P<0.0001), apolipoprotein (apo) B (β=0.258, P<0.0001), and liver fat (β=0.191, P=0.002) and negatively with high-density lipoprotein cholesterol (β=-0.442, P<0.0001). rbp4 was correlated positively with apoB100 very-low-density lipoprotein (VLDL) pool (r=0.62, P=0.017) and negatively with VLDL-apoB100 total fractional catabolic rate (r=-0.66, P=0.001). In multivariate analysis, rbp4 (P=0.015), plasma triglycerides (P=0.024), and sex (P=0.026) were independently associated with VLDL-apoB100 total fractional catabolic rate. CONCLUSIONS In T2DM, plasma rbp4 level is associated with plasma triglycerides, independently of liver fat content. There is a strong independent negative correlation between plasma rbp4 and VLDL-apoB100 total fractional catabolic rate. These data suggest that rbp4 may be involved in the pathophysiology of hypertriglyceridemia in T2DM by reducing VLDL catabolism.
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Affiliation(s)
- Bruno Vergès
- Department of Endocrinology-Diabetology, University Hospital, Dijon, France.
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Carneiro MM, Miname MH, Gagliardi AC, Pereira C, Pereira AC, Krieger JE, Maranhão RC, Santos RD. The removal from plasma of chylomicrons and remnants is reduced in heterozygous familial hypercholesterolemia subjects with identified LDL receptor mutations: Study with artificial emulsions. Atherosclerosis 2012; 221:268-74. [DOI: 10.1016/j.atherosclerosis.2011.12.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 12/20/2011] [Accepted: 12/21/2011] [Indexed: 10/14/2022]
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Tada H, Kawashiri MA, Ikewaki K, Terao Y, Noguchi T, Nakanishi C, Tsuchida M, Takata M, Miwa K, Konno T, Hayashi K, Nohara A, Inazu A, Kobayashi J, Mabuchi H, Yamagishi M. Altered Metabolism of Low-Density Lipoprotein and Very-Low-Density Lipoprotein Remnant in Autosomal Recessive Hypercholesterolemia. ACTA ACUST UNITED AC 2012; 5:35-41. [DOI: 10.1161/circgenetics.111.960948] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Autosomal recessive hypercholesterolemia (ARH) exhibits different responsiveness to statins compared with that in homozygous familial hypercholesterolemia (FH). However, few data exist regarding lipoprotein metabolism of ARH. Therefore, we aimed to clarify lipoprotein metabolism, especially the remnant lipoprotein fractions of ARH before and after statin therapy.
Methods and Results—
We performed a lipoprotein kinetic study in an ARH patient and 7 normal control subjects, using stable isotope methodology (10 mg/kg of [
2
H
3
]-leucine). These studies were performed at baseline and after the 20 mg daily dose of atorvastatin. Tracer/tracee ratio of apolipoprotein B (apoB) was determined by gas chromatography/mass spectrometry and fractional catabolic rates (FCR) were determined by multicompartmental modeling, including remnant lipoprotein fractions. FCR of low-density lipoprotein (LDL) apoB of ARH was significantly lower than those of control subjects (0.109 versus 0.450±0.122 1/day). In contrast, the direct removal of very-low-density lipoprotein remnant was significantly greater in ARH than those in control subjects (47.5 versus 2±2%). Interestingly, FCR of LDL apoB in ARH dramatically increased to 0.464 1/day, accompanying reduction of LDL cholesterol levels from 8.63 to 4.22 mmol/L after treatment with atorvastatin of 20 mg/d for 3 months.
Conclusions—
These results demonstrate that ARH exhibits decreased LDL clearance associated with decreased FCR of LDL apoB and increased clearance for very-low-density lipoprotein remnant. We suggest that increased clearance of remnant lipoprotein fractions could contribute to the great responsiveness to statins, providing new insights into the lipoprotein metabolism of ARH and the novel pharmacological target for LDLRAP1.
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Affiliation(s)
- Hayato Tada
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Masa-aki Kawashiri
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Katsunori Ikewaki
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Yoshio Terao
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Tohru Noguchi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Chiaki Nakanishi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Masayuki Tsuchida
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Mutsuko Takata
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Kenji Miwa
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Tetsuo Konno
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Kenshi Hayashi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Atsushi Nohara
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Akihiro Inazu
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Junji Kobayashi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Hiroshi Mabuchi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
| | - Masakazu Yamagishi
- From the Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, Kanazawa, Japan (H.T., M.-a.K., C.N., M. Tsuchida, M. Takata, T.K., K.H., M.Y.); the Division of Anti-Aging, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan (K.I.); the Division of Cardiology, Department of Internal Medicine, Jikei University School of Medicine, Tokyo, Japan (Y.T.); the Department of Lipidology, Kanazawa University Graduate School of Medicine, Kanazawa,
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Lee AYH, Yates NA, Ichetovkin M, Deyanova E, Southwick K, Fisher TS, Wang W, Loderstedt J, Walker N, Zhou H, Zhao X, Sparrow CP, Hubbard BK, Rader DJ, Sitlani A, Millar JS, Hendrickson RC. Measurement of fractional synthetic rates of multiple protein analytes by triple quadrupole mass spectrometry. Clin Chem 2012; 58:619-27. [PMID: 22249652 DOI: 10.1373/clinchem.2011.172429] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND Current approaches to measure protein turnover that use stable isotope-labeled tracers via GC-MS are limited to a small number of relatively abundant proteins. We developed a multiplexed liquid chromatography-selected reaction monitoring mass spectrometry (LC-SRM) assay to measure protein turnover and compared the fractional synthetic rates (FSRs) for 2 proteins, VLDL apolipoprotein B100 (VLDL apoB100) and HDL apoA-I, measured by both methods. We applied this technique to other proteins for which kinetics are not readily measured with GC-MS. METHODS Subjects were given a primed-constant infusion of [5,5,5-D(3)]-leucine (D(3)-leucine) for 15 h with blood samples collected at selected time points. Apolipoproteins isolated by SDS-PAGE from lipoprotein fractions were analyzed by GC-MS or an LC-SRM assay designed to measure the M+3/M+0 ratio at >1% D(3)-leucine incorporation. We calculated the FSR for each apolipoprotein by curve fitting the tracer incorporation data from each subject. RESULTS The LC-SRM method was linear over the range of tracer enrichment values tested and highly correlated with GC-MS (R(2) > 0.9). The FSRs determined from both methods were similar for HDL apoA-I and VLDL apoB100. We were able to apply the LC-SRM approach to determine the tracer enrichment of multiple proteins from a single sample as well as proteins isolated from plasma after immunoprecipitation. CONCLUSIONS The LC-SRM method provides a new technique for measuring the enrichment of proteins labeled with stable isotopes. LC-SRM is amenable to a multiplexed format to provide a relatively rapid and inexpensive means to measure turnover of multiple proteins simultaneously.
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Affiliation(s)
- Anita Y H Lee
- Molecular Biomarker Laboratory, Merck Research Laboratories, Rahway, NJ, USA
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Chan DC, Watts GF. Postprandial lipoprotein metabolism in familial hypercholesterolemia: thinking outside the box. Metabolism 2012; 61:3-11. [PMID: 21945105 DOI: 10.1016/j.metabol.2011.07.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Revised: 07/14/2011] [Accepted: 07/26/2011] [Indexed: 10/17/2022]
Abstract
Familial hypercholesterolemia (FH) is a dominantly inherited disorder principally due to mutations in the low-density lipoprotein (LDL) receptor that classically cause markedly elevated plasma LDL cholesterol concentrations and premature coronary heart disease (CHD). However, elevated plasma LDL cholesterol alone does not fully account for the increase or variation in risk of CHD. We propose a hypothetical model for the role of postprandial dyslipoproteinemia based on the overproduction and decreased catabolism of triglyceride-rich lipoproteins, which may be a consequence of LDL receptor deficiency. Expression of postprandial dyslipoproteinemia in FH may also depend on the type of pathogenic gene variants and on coexistent conditions, particularly obesity and insulin resistance. Further research is required to investigate our model proposed and to test whether treating postprandial dyslipoproteinemia decreases CHD risk in FH incremental to standard therapy.
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Affiliation(s)
- Dick C Chan
- Metabolic Research Centre, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia
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Yucel O, Karahan O, Zorlu A, Manduz S. Familial genetic risk factors in premature cardiovascular disease: a family study. Mol Biol Rep 2011; 39:6141-7. [DOI: 10.1007/s11033-011-1430-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Accepted: 12/19/2011] [Indexed: 01/11/2023]
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Vergès B, Duvillard L, Brindisi MC, Gautier E, Krempf M, Costet P, Cariou B. Lack of association between plasma PCSK9 and LDL-apoB100 catabolism in patients with uncontrolled type 2 diabetes. Atherosclerosis 2011; 219:342-8. [DOI: 10.1016/j.atherosclerosis.2011.07.098] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 07/04/2011] [Accepted: 07/14/2011] [Indexed: 11/26/2022]
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Calandra S, Tarugi P, Speedy HE, Dean AF, Bertolini S, Shoulders CC. Mechanisms and genetic determinants regulating sterol absorption, circulating LDL levels, and sterol elimination: implications for classification and disease risk. J Lipid Res 2011; 52:1885-926. [PMID: 21862702 DOI: 10.1194/jlr.r017855] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
This review integrates historical biochemical and modern genetic findings that underpin our understanding of the low-density lipoprotein (LDL) dyslipidemias that bear on human disease. These range from life-threatening conditions of infancy through severe coronary heart disease of young adulthood, to indolent disorders of middle- and old-age. We particularly focus on the biological aspects of those gene mutations and variants that impact on sterol absorption and hepatobiliary excretion via specific membrane transporter systems (NPC1L1, ABCG5/8); the incorporation of dietary sterols (MTP) and of de novo synthesized lipids (HMGCR, TRIB1) into apoB-containing lipoproteins (APOB) and their release into the circulation (ANGPTL3, SARA2, SORT1); and receptor-mediated uptake of LDL and of intestinal and hepatic-derived lipoprotein remnants (LDLR, APOB, APOE, LDLRAP1, PCSK9, IDOL). The insights gained from integrating the wealth of genetic data with biological processes have important implications for the classification of clinical and presymptomatic diagnoses of traditional LDL dyslipidemias, sitosterolemia, and newly emerging phenotypes, as well as their management through both nutritional and pharmaceutical means.
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Affiliation(s)
- Sebastiano Calandra
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy.
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Soufi M, Kurt B, Schweer H, Sattler AM, Klaus G, Zschocke J, Schaefer JR. Genetics and kinetics of familial hypercholesterolemia, with the special focus on FH-(Marburg) p.W556R. ATHEROSCLEROSIS SUPP 2011; 10:5-11. [PMID: 20129366 DOI: 10.1016/s1567-5688(09)71802-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Familial hypercholesterolemia (FH) is an autosomal dominant inherited disorder, caused by mutations in the low density lipoprotein receptor (LDLR) gene. FH is characterized by elevated plasma LDL cholesterol, premature atherosclerosis and high risk of premature myocardial infarction. Extended work has been done to understand both, the primary genetic defect as well as the in vivo kinetic consequences of this disease. Both approaches, genetics and kinetics, are challenging but also fruitful approaches for a better understanding of this devastating disease. For this we reviewed the recent literature and used our in vitro and in vivo data on one of the most frequently occurring types of FH, the FH(Marburg) p.W556R. METHODS To identify the primary genetic defect of the FH(Marburg) we used denaturing gradient gel electrophoresis (DGGE) mutation analysis. In vivo kinetic studies were performed in a heterozygote FH(Marburg) subject and in 5 healthy control subjects utilizing a stable isotope tracer kinetic approach with 3D-leucine. RESULTS DGGE screening of the LDLR gene identified a tryptophan (W) to arginine (R) substitution at residue 556 (p.W556R) in the fifth conserved YWTD repeat of the LDLR-beta-propeller in FH(Marburg). In vivo kinetic studies in a heterozygote FH subject for FH(Marburg) and in 5 healthy control subjects demonstrated a severe decrease in LDL FCR and a mild increase of LDL PR in FH compared to healthy controls. CONCLUSIONS The LDLR mutation p.W556R is a frequent and severe defect for FH. This defect has a major influence on the in vivo lipoprotein kinetics and lipid levels. In a heterozygote FH patient we found a dual defect for the increase in LDL cholesterol, namely a decrease in the fractional catabolic rate (FCR) of LDL but also an increase in LDL production rate (PR). By this a well defined, single genetic defect may have a series of different in vivo metabolic consequences which could be used for potential therapeutic approaches to this disease.
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Affiliation(s)
- Muhidien Soufi
- Department of Internal Medicine, Cardiology, Philipps-University, Marburg, Germany
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Kolovou GD, Kostakou PM, Anagnostopoulou KK. Familial hypercholesterolemia and triglyceride metabolism. Int J Cardiol 2011; 147:349-58. [DOI: 10.1016/j.ijcard.2010.08.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Revised: 06/24/2010] [Accepted: 08/08/2010] [Indexed: 12/14/2022]
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Christoffersen C, Pedersen TX, Gordts PLSM, Roebroek AJM, Dahlbäck B, Nielsen LB. Opposing effects of apolipoprotein m on catabolism of apolipoprotein B-containing lipoproteins and atherosclerosis. Circ Res 2010; 106:1624-34. [PMID: 20360257 DOI: 10.1161/circresaha.109.211086] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Plasma apolipoprotein (apo)M is mainly associated with high-density lipoprotein (HDL). HDL-bound apoM is antiatherogenic in vitro. However, plasma apoM is not associated with coronary heart disease in humans, perhaps because of a positive correlation with plasma low-density lipoprotein (LDL). OBJECTIVE We explored putative links between apoM and very-low-density (VLDL)/LDL metabolism and the antiatherogenic potential of apoM in vivo. METHODS AND RESULTS Plasma apoM was increased approximately 2.1 and approximately 1.5 fold in mice lacking LDL receptors (Ldlr(-/-)) and expressing dysfunctional LDL receptor-related protein 1 (Lrp1(n2/n2)), respectively, but was unaffected in apoE-deficient (ApoE(-/-)) mice. Thus, pathways controlling catabolism of VLDL and LDL affect plasma apoM. Overexpression (approximately 10-fold) of human apoM increased (50% to 70%) and apoM deficiency decreased ( approximately 25%) plasma VLDL/LDL cholesterol in Ldlr(-/-) mice, whereas apoM did not affect plasma VLDL/LDL in mice with intact LDL receptors. Moreover, plasma clearance of apoM-enriched VLDL/LDL was slower than that of control VLDL/LDL in mice lacking functional LDL receptors and LRP1, suggesting that apoM impairs the catabolism of VLDL/LDL that occurs independently of the LDL receptor and LRP1. ApoM overexpression decreased atherosclerosis in ApoE(-/-) (60%) and cholate/cholesterol-fed wild-type mice (70%). However, in Ldlr(-/-) mice the antiatherogenic effect of apoM was attenuated by its VLDL/LDL-raising effect. CONCLUSION The data suggest that defect LDL receptor function leads to increased plasma apoM concentrations, which in turn, impairs the removal of VLDL/LDL from plasma. This mechanism opposes the otherwise antiatherogenic effect of apoM.
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