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Reijnders E, van der Laarse A, Ruhaak LR, Cobbaert CM. Closing the gaps in patient management of dyslipidemia: stepping into cardiovascular precision diagnostics with apolipoprotein profiling. Clin Proteomics 2024; 21:19. [PMID: 38429638 PMCID: PMC10908091 DOI: 10.1186/s12014-024-09465-w] [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: 09/18/2023] [Accepted: 02/14/2024] [Indexed: 03/03/2024] Open
Abstract
In persons with dyslipidemia, a high residual risk of cardiovascular disease remains despite lipid lowering therapy. Current cardiovascular risk prediction mainly focuses on low-density lipoprotein cholesterol (LDL-c) levels, neglecting other contributing risk factors. Moreover, the efficacy of LDL-c lowering by statins resulting in reduced cardiovascular risk is only partially effective. Secondly, from a metrological viewpoint LDL-c falls short as a reliable measurand. Both direct and calculated LDL-c tests produce inaccurate test results at the low end under aggressive lipid lowering therapy. As LDL-c tests underperform both clinically and metrologically, there is an urging need for molecularly defined biomarkers. Over the years, apolipoproteins have emerged as promising biomarkers in the context of cardiovascular disease as they are the functional workhorses in lipid metabolism. Among these, apolipoprotein B (ApoB), present on all atherogenic lipoprotein particles, has demonstrated to clinically outperform LDL-c. Other apolipoproteins, such as Apo(a) - the characteristic apolipoprotein of the emerging risk factor lipoprotein(a) -, and ApoC-III - an inhibitor of triglyceride-rich lipoprotein clearance -, have attracted attention as well. To support personalized medicine, we need to move to molecularly defined risk markers, like the apolipoproteins. Molecularly defined diagnosis and molecularly targeted therapy require molecularly measured biomarkers. This review provides a summary of the scientific validity and (patho)physiological role of nine serum apolipoproteins, Apo(a), ApoB, ApoC-I, ApoC-II, ApoC-III, ApoE and its phenotypes, ApoA-I, ApoA-II, and ApoA-IV, in lipid metabolism, their association with cardiovascular disease, and their potential as cardiovascular risk markers when measured in a multiplex apolipoprotein panel.
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Affiliation(s)
- Esther Reijnders
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands.
| | - Arnoud van der Laarse
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - L Renee Ruhaak
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | - Christa M Cobbaert
- Department of Clinical Chemistry and Laboratory Medicine, Leiden University Medical Center, Leiden, the Netherlands
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2
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Afanasieva OI, Tyurina AV, Ezhov MV, Razova OA, Klesareva EA, Pokrovsky SN. Lipoprotein(a) and Low-Molecular-Weight Apo(a) Phenotype as Determinants of New Cardiovascular Events in Patients with Premature Coronary Heart Disease. Diseases 2023; 11:145. [PMID: 37873789 PMCID: PMC10594435 DOI: 10.3390/diseases11040145] [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: 07/01/2023] [Revised: 09/29/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023] Open
Abstract
BACKGROUND Lipoprotein(a) (Lp(a)) is a genetic risk factor of atherosclerotic cardiovascular diseases (ASCVDs). Proprotein convertase subtilisin/kexin type 9 (PCSK9) is related to vascular inflammation and detected in atherosclerotic plaques. A temporary increase in the circulating concentration of PCSK9 and Lp(a) was shown in patients with myocardial infarction (MI). The aim of this study was to evaluate the role of the apo(a) phenotype and the Lp(a) concentration as well as its complex with PCSK9 in the development of cardiac events and MI in patients with a premature manifestation of coronary heart disease (CHD). METHODS In a prospective study with retrospective data collection, we included 116 patients with premature CHD who were followed for a median of 14 years. The medical history and information on cardiovascular events after an initial exam as well as data on the levels of lipids, Lp(a), PCSK9, PCSK9-Lp(a) complex, and apo(a) phenotype were obtained. RESULTS The patients were divided into two groups depending on the presence of a low- (LMW, n = 52) or high-molecular weight (HMW, n = 64) apo(a) phenotype. LMW apo(a) phenotype (odds ratio 2.3 (1.1 to 4.8), p = 0.03), but not elevated Lp(a) (1.9 (0.8-4.6), p = 0.13), was an independent predictor for the development of MI after adjustment for sex, age of CHD debut, initial lipids levels, and lipid-lowering treatment. The apo(a) phenotype also determined the relationship between Lp(a) and PCSK9 concentrations. The level of the PCSK9-Lp(a) complex was higher in LMW apo(a) patients. CONCLUSION The LMW apo(a) phenotype is a risk factor for non-fatal MI in a long-term prospective follow-up of patients with premature CHD, and this link could be mediated via PCSK9.
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Affiliation(s)
- Olga I. Afanasieva
- Institute of Experimental Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia; (O.I.A.); (O.A.R.); (E.A.K.); (S.N.P.)
| | - Alexandra V. Tyurina
- A.L. Myasnikov Institute of Clinical Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia;
| | - Marat V. Ezhov
- A.L. Myasnikov Institute of Clinical Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia;
| | - Oxana A. Razova
- Institute of Experimental Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia; (O.I.A.); (O.A.R.); (E.A.K.); (S.N.P.)
| | - Elena A. Klesareva
- Institute of Experimental Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia; (O.I.A.); (O.A.R.); (E.A.K.); (S.N.P.)
| | - Sergei N. Pokrovsky
- Institute of Experimental Cardiology, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Ministry of Health of the Russian Federation, Academician Chazov str., 15a, 121552 Moscow, Russia; (O.I.A.); (O.A.R.); (E.A.K.); (S.N.P.)
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Chiesa G, Zenti MG, Baragetti A, Barbagallo CM, Borghi C, Colivicchi F, Maggioni AP, Noto D, Pirro M, Rivellese AA, Sampietro T, Sbrana F, Arca M, Averna M, Catapano AL. Consensus document on Lipoprotein(a) from the Italian Society for the Study of Atherosclerosis (SISA). Nutr Metab Cardiovasc Dis 2023; 33:1866-1877. [PMID: 37586921 DOI: 10.1016/j.numecd.2023.07.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 07/07/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
AIMS In view of the consolidating evidence on the causal role of Lp(a) in cardiovascular disease, the Italian Society for the Study of Atherosclerosis (SISA) has assembled a consensus on Lp(a) genetics and epidemiology, together with recommendations for its measurement and current and emerging therapeutic approaches to reduce its plasma levels. Data on the Italian population are also provided. DATA SYNTHESIS Lp(a) is constituted by one apo(a) molecule and a lipoprotein closely resembling to a low-density lipoprotein (LDL). Its similarity with an LDL, together with its ability to carry oxidized phospholipids are considered the two main features making Lp(a) harmful for cardiovascular health. Plasma Lp(a) concentrations vary over about 1000 folds in humans and are genetically determined, thus they are quite stable in any individual. Mendelian Randomization studies have suggested a causal role of Lp(a) in atherosclerotic cardiovascular disease (ASCVD) and aortic valve stenosis and observational studies indicate a linear direct correlation between cardiovascular disease and Lp(a) plasma levels. Lp(a) measurement is strongly recommended once in a patient's lifetime, particularly in FH subjects, but also as part of the initial lipid screening to assess cardiovascular risk. The apo(a) size polymorphism represents a challenge for Lp(a) measurement in plasma, but new strategies are overcoming these difficulties. A reduction of Lp(a) levels can be currently attained only by plasma apheresis and, moderately, with PCSK9 inhibitor treatment. CONCLUSIONS Awaiting the approval of selective Lp(a)-lowering drugs, an intensive management of the other risk factors for individuals with elevated Lp(a) levels is strongly recommended.
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Affiliation(s)
- Giulia Chiesa
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università Degli Studi di Milano, Milan, Italy.
| | - Maria Grazia Zenti
- Section of Diabetes and Metabolism, Pederzoli Hospital, Peschiera Del Garda, Verona, Italy.
| | - Andrea Baragetti
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università Degli Studi di Milano, Milan, Italy; IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
| | - Carlo M Barbagallo
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, Palermo, Italy
| | - Claudio Borghi
- Department of Cardiovascular Medicine, IRCCS AOU S. Orsola, Bologna, Italy
| | - Furio Colivicchi
- Division of Clinical Cardiology, San Filippo Neri Hospital, Rome, Italy
| | - Aldo P Maggioni
- ANMCO Research Center, Heart Care Foundation, Firenze, Italy
| | - Davide Noto
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, Palermo, Italy
| | - Matteo Pirro
- Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Medicine and Surgery, University of Perugia, Italy
| | - Angela A Rivellese
- Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy
| | - Tiziana Sampietro
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Francesco Sbrana
- Lipoapheresis Unit, Reference Center for Diagnosis and Treatment of Inherited Dyslipidemias, Fondazione Toscana Gabriele Monasterio, Pisa, Italy
| | - Marcello Arca
- Department of Translational and Precision Medicine (DTPM), Sapienza University of Rome, Policlinico Umberto I, Rome, Italy
| | - Maurizio Averna
- Department of Health Promotion, Mother and Child Care, Internal Medicine and Medical Specialties (PROMISE), University of Palermo, Palermo, Italy; Institute of Biophysics, National Council of Researches, Palermo, Italy
| | - Alberico L Catapano
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", Università Degli Studi di Milano, Milan, Italy; IRCCS MultiMedica, Sesto San Giovanni, Milan, Italy
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Abstract
PURPOSE OF REVIEW This review summarizes our current understanding of the processes of apolipoprotein(a) secretion, assembly of the Lp(a) particle and removal of Lp(a) from the circulation. We also identify existing knowledge gaps that need to be addressed in future studies. RECENT FINDINGS The Lp(a) particle is assembled in two steps: a noncovalent, lysine-dependent interaction of apo(a) with apoB-100 inside hepatocytes, followed by extracellular covalent association between these two molecules to form circulating apo(a).The production rate of Lp(a) is primarily responsible for the observed inverse correlation between apo(a) isoform size and Lp(a) levels, with a contribution of catabolism restricted to larger Lp(a) isoforms.Factors that affect apoB-100 secretion from hepatocytes also affect apo(a) secretion.The identification of key hepatic receptors involved in Lp(a) clearance in vivo remains unclear, with a role for the LDL receptor seemingly restricted to conditions wherein LDL concentrations are low, Lp(a) is highly elevated and LDL receptor number is maximally upregulated. SUMMARY The key role for production rate of Lp(a) [including secretion and assembly of the Lp(a) particle] rather than its catabolic rate suggests that the most fruitful therapies for Lp(a) reduction should focus on approaches that inhibit production of the particle rather than its removal from circulation.
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Affiliation(s)
| | - Marlys L Koschinsky
- Robarts Research Institute
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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Chemello K, Chan DC, Lambert G, Watts GF. Recent advances in demystifying the metabolism of lipoprotein(a). Atherosclerosis 2022; 349:82-91. [DOI: 10.1016/j.atherosclerosis.2022.04.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 03/29/2022] [Accepted: 04/01/2022] [Indexed: 12/24/2022]
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Clark JR, Gemin M, Youssef A, Marcovina SM, Prat A, Seidah NG, Hegele RA, Boffa MB, Koschinsky ML. Sortilin enhances secretion of apolipoprotein(a) through effects on apolipoprotein B secretion and promotes uptake of lipoprotein(a). J Lipid Res 2022; 63:100216. [PMID: 35469919 PMCID: PMC9131257 DOI: 10.1016/j.jlr.2022.100216] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/06/2022] [Accepted: 04/08/2022] [Indexed: 12/30/2022] Open
Abstract
Elevated plasma lipoprotein(a) (Lp(a)) is an independent, causal risk factor for atherosclerotic cardiovascular disease and calcific aortic valve stenosis. Lp(a) is formed in or on hepatocytes from successive noncovalent and covalent interactions between apo(a) and apoB, although the subcellular location of these interactions and the nature of the apoB-containing particle involved remain unclear. Sortilin, encoded by the SORT1 gene, modulates apoB secretion and LDL clearance. We used a HepG2 cell model to study the secretion kinetics of apo(a) and apoB. Overexpression of sortilin increased apo(a) secretion, while siRNA-mediated knockdown of sortilin expression correspondingly decreased apo(a) secretion. Sortilin binds LDL but not apo(a) or Lp(a), indicating that its effect on apo(a) secretion is likely indirect. Indeed, the effect was dependent on the ability of apo(a) to interact noncovalently with apoB. Overexpression of sortilin enhanced internalization of Lp(a), but not apo(a), by HepG2 cells, although neither sortilin knockdown in these cells or Sort1 deficiency in mice impacted Lp(a) uptake. We found several missense mutations in SORT1 in patients with extremely high Lp(a) levels; sortilin containing some of these mutations was more effective at promoting apo(a) secretion than WT sortilin, though no differences were found with respect to Lp(a) internalization. Our observations suggest that sortilin could play a role in determining plasma Lp(a) levels and corroborate in vivo human kinetic studies which imply that secretion of apo(a) and apoB are coupled, likely within the hepatocyte.
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Affiliation(s)
- Justin R Clark
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Matthew Gemin
- Department of Chemistry & Biochemistry, University of Windsor, Windsor, ON, Canada
| | - Amer Youssef
- Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | | | - Annik Prat
- Institut de Recherches Cliniques de Montreal, Montréal, QC, Canada
| | - Nabil G Seidah
- Institut de Recherches Cliniques de Montreal, Montréal, QC, Canada
| | - Robert A Hegele
- Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada; Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada; Department of Medicine, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Michael B Boffa
- Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada; Department of Biochemistry, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Marlys L Koschinsky
- Department of Physiology & Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada; Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada.
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Kostner KM, Kostner GM. Lp(a) and the Risk for Cardiovascular Disease: Focus on the Lp(a) Paradox in Diabetes Mellitus. Int J Mol Sci 2022. [DOI: https://doi.org/10.3390/ijms23073584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Lipoprotein(a) (Lp(a)) is one of the strongest causal risk factors of atherosclerotic disease. It is rich in cholesteryl ester and composed of apolipoprotein B and apo(a). Plasma Lp(a) levels are determined by apo(a) transcriptional activity driven by a direct repeat (DR) response element in the apo(a) promoter under the control of (HNF)4α Farnesoid-X receptor (FXR) ligands play a key role in the downregulation of APOA expression. In vitro studies on the catabolism of Lp(a) have revealed that Lp(a) binds to several specific lipoprotein receptors; however, their in vivo role remains elusive. There are more than 1000 publications on the role of diabetes mellitus (DM) in Lp(a) metabolism; however, the data is often inconsistent and confusing. In patients suffering from Type-I diabetes mellitus (T1DM), provided they are metabolically well-controlled, Lp(a) plasma concentrations are directly comparable to healthy individuals. In contrast, there exists a paradox in T2DM patients, as many of these patients have reduced Lp(a) levels; however, they are still at an increased cardiovascular risk. The Lp(a) lowering mechanism observed in T2DM patients is most probably caused by mutations in the mature-onset diabetes of the young (MODY) gene and possibly other polymorphisms in key transcription factors of the apolipoprotein (a) gene (APOA).
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Lp(a) and the Risk for Cardiovascular Disease: Focus on the Lp(a) Paradox in Diabetes Mellitus. Int J Mol Sci 2022; 23:ijms23073584. [PMID: 35408941 PMCID: PMC8998850 DOI: 10.3390/ijms23073584] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/21/2022] [Accepted: 03/21/2022] [Indexed: 11/16/2022] Open
Abstract
Lipoprotein(a) (Lp(a)) is one of the strongest causal risk factors of atherosclerotic disease. It is rich in cholesteryl ester and composed of apolipoprotein B and apo(a). Plasma Lp(a) levels are determined by apo(a) transcriptional activity driven by a direct repeat (DR) response element in the apo(a) promoter under the control of (HNF)4α Farnesoid-X receptor (FXR) ligands play a key role in the downregulation of APOA expression. In vitro studies on the catabolism of Lp(a) have revealed that Lp(a) binds to several specific lipoprotein receptors; however, their in vivo role remains elusive. There are more than 1000 publications on the role of diabetes mellitus (DM) in Lp(a) metabolism; however, the data is often inconsistent and confusing. In patients suffering from Type-I diabetes mellitus (T1DM), provided they are metabolically well-controlled, Lp(a) plasma concentrations are directly comparable to healthy individuals. In contrast, there exists a paradox in T2DM patients, as many of these patients have reduced Lp(a) levels; however, they are still at an increased cardiovascular risk. The Lp(a) lowering mechanism observed in T2DM patients is most probably caused by mutations in the mature-onset diabetes of the young (MODY) gene and possibly other polymorphisms in key transcription factors of the apolipoprotein (a) gene (APOA).
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Kostner KM, Kostner GM. Lp(a) and the Risk for Cardiovascular Disease: Focus on the Lp(a) Paradox in Diabetes Mellitus. Int J Mol Sci 2022. [DOI: https:/doi.org/10.3390/ijms23073584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Lipoprotein(a) (Lp(a)) is one of the strongest causal risk factors of atherosclerotic disease. It is rich in cholesteryl ester and composed of apolipoprotein B and apo(a). Plasma Lp(a) levels are determined by apo(a) transcriptional activity driven by a direct repeat (DR) response element in the apo(a) promoter under the control of (HNF)4α Farnesoid-X receptor (FXR) ligands play a key role in the downregulation of APOA expression. In vitro studies on the catabolism of Lp(a) have revealed that Lp(a) binds to several specific lipoprotein receptors; however, their in vivo role remains elusive. There are more than 1000 publications on the role of diabetes mellitus (DM) in Lp(a) metabolism; however, the data is often inconsistent and confusing. In patients suffering from Type-I diabetes mellitus (T1DM), provided they are metabolically well-controlled, Lp(a) plasma concentrations are directly comparable to healthy individuals. In contrast, there exists a paradox in T2DM patients, as many of these patients have reduced Lp(a) levels; however, they are still at an increased cardiovascular risk. The Lp(a) lowering mechanism observed in T2DM patients is most probably caused by mutations in the mature-onset diabetes of the young (MODY) gene and possibly other polymorphisms in key transcription factors of the apolipoprotein (a) gene (APOA).
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Afanasieva OI, Ezhov MV, Tmoyan NA, Razova OA, Afanasieva MI, Matchin YG, Pokrovsky SN. Low Molecular Weight Apolipoprotein(a) Phenotype Rather Than Lipoprotein(a) Is Associated With Coronary Atherosclerosis and Myocardial Infarction. Front Cardiovasc Med 2022; 9:843602. [PMID: 35369320 PMCID: PMC8965702 DOI: 10.3389/fcvm.2022.843602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 02/15/2022] [Indexed: 11/13/2022] Open
Abstract
Background and AimsCurrent evidence suggests that lipoprotein(a) [Lp(a)] level above 50 mg/dL is associated with increased cardiovascular risk. Our study aim was to determine the relationship of apolipoprotein(a) [apo(a)] phenotypes and Lp(a) concentration below and above 50 mg/dL with coronary atherosclerosis severity and myocardial infarction (MI).Material and MethodsThe study population consisted of 540 patients (mean age 54.0 ± 8.8 years, 82% men) who passed through coronary angiography. The number of diseased major coronary arteries assessed atherosclerosis severity. Lipids, glucose, Lp(a) levels and apo(a) phenotypes were determined in all patients. All patients were divided into four groups: with Lp(a) <50 mg/dL [ “normal” Lp(a)] or ≥50 mg/dL [hyperLp(a)], and with low-molecular (LMW) or high-molecular weight (HMW) apo(a) phenotypes.ResultsBaseline clinical and biochemical characteristics were similar between the groups. In groups with LMW apo(a) phenotypes, the odds ratio (OR; 95% confidence interval) of multivessel disease was higher [10.1; 3.1–33.5, p < 0.005 for hyperLp(a) and 2.2; 1.0–4.9, p = 0.056 for normal Lp(a)], but not in the group with HMW apo(a) and hyperLp(a) [1.1; 0.3–3.3, p = 0.92] compared with the reference group with HMW apo(a) and normal Lp(a). Similarly, MI was observed more often in patients with LMW apo(a) phenotype and hyperLp(a) and normal Lp(a) than in groups with HMW apo(a) phenotype.ConclusionThe LMW apo(a) phenotype is associated with the severity of coronary atherosclerosis and MI even when Lp(a) level is below 50 mg/dL. The combination of Lp(a) level above 50 mg/dL and LMW apo(a) phenotype increases the risk of severe coronary atherosclerosis, regardless of other risk factors.
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Affiliation(s)
- Olga I. Afanasieva
- National Medical Research Center of Cardiology, Institute of Experimental Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Marat V. Ezhov
- National Medical Research Center of Cardiology, A. L. Myasnikov Institute of Clinical Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
- *Correspondence: Marat V. Ezhov
| | - Narek A. Tmoyan
- National Medical Research Center of Cardiology, A. L. Myasnikov Institute of Clinical Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Oksana A. Razova
- National Medical Research Center of Cardiology, Institute of Experimental Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Marina I. Afanasieva
- National Medical Research Center of Cardiology, Institute of Experimental Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Yuri G. Matchin
- National Medical Research Center of Cardiology, A. L. Myasnikov Institute of Clinical Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
| | - Sergei N. Pokrovsky
- National Medical Research Center of Cardiology, Institute of Experimental Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
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Youssef A, Clark JR, Marcovina SM, Boffa MB, Koschinsky ML. Apo(a) and ApoB Interact Noncovalently Within Hepatocytes: Implications for Regulation of Lp(a) Levels by Modulation of ApoB Secretion. Arterioscler Thromb Vasc Biol 2022; 42:289-304. [PMID: 35045727 DOI: 10.1161/atvbaha.121.317335] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Elevated plasma Lp(a) (lipoprotein(a)) levels are associated with increased risk for atherosclerotic cardiovascular disease and aortic valve stenosis. However, the cell biology of Lp(a) biosynthesis remains poorly understood, with the locations of the noncovalent and covalent steps of Lp(a) assembly unclear and the nature of the apoB-containing particle destined for Lp(a) unknown. We, therefore, asked if apo(a) and apoB interact noncovalently within hepatocytes and if this impacts Lp(a) biosynthesis. METHODS Using human hepatocellular carcinoma cells expressing 17K (17 kringle) apo(a), or a 17KΔLBS7,8 variant with a reduced ability to bind noncovalently to apoB, we performed coimmunoprecipitation, coimmunofluorescence, and proximity ligation assays to document intracellular apo(a):apoB interactions. We used a pulse-chase metabolic labeling approach to measure apo(a) and apoB secretion rates. RESULTS Noncovalent complexes containing apo(a)/apoB are present in lysates from cells expressing 17K but not 17KΔLBS7,8, whereas covalent apo(a)/apoB complexes are absent from lysates. 17K and apoB colocalized intracellularly, overlapping with staining for markers of endoplasmic reticulum trans-Golgi, and early endosomes, and less so with lysosomes. The 17KΔLBS7,8 had lower colocalization with apoB. Proximity ligation assays directly documented intracellular 17K/apoB interactions, which were dramatically reduced for 17KΔLBS7,8. Treatment of cells with PCSK9 (proprotein convertase subtilisin/kexin type 9) enhanced, and lomitapide reduced, apo(a) secretion in a manner dependent on the noncovalent interaction between apo(a) and apoB. Apo(a) secretion was also reduced by siRNA-mediated knockdown of APOB. CONCLUSIONS Our findings explain the coupling of apo(a) and Lp(a)-apoB production observed in human metabolic studies using stable isotopes as well as the ability of agents that inhibit apoB biosynthesis to lower Lp(a) levels.
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Affiliation(s)
- Amer Youssef
- Robarts Research Institute (A.Y., M.B.B., M.L.K.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada
| | - Justin R Clark
- Department of Physiology & Pharmacology (J.R.C., M.L.K.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada
| | | | - Michael B Boffa
- Robarts Research Institute (A.Y., M.B.B., M.L.K.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada.,Department of Biochemistry (M.B.B.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada
| | - Marlys L Koschinsky
- Robarts Research Institute (A.Y., M.B.B., M.L.K.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada.,Department of Physiology & Pharmacology (J.R.C., M.L.K.), Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada
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Handhle A, Viljoen A, Wierzbicki AS. Elevated Lipoprotein(a): Background, Current Insights and Future Potential Therapies. Vasc Health Risk Manag 2021; 17:527-542. [PMID: 34526771 PMCID: PMC8436116 DOI: 10.2147/vhrm.s266244] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 08/13/2021] [Indexed: 12/13/2022] Open
Abstract
Lipoprotein(a) forms a subfraction of the lipid profile and is characterized by the addition of apolipprotein(a) (apo(a)) to apoB100 derived particles. Its levels are mostly genetically determined inversely related to the number of protein domain (kringle) repeats in apo(a). In epidemiological studies, it shows consistent association with cardiovascular disease (CVD) and most recently with extent of aortic stenosis. Issues with standardizing the measurement of Lp(a) are being resolved and consensus statements favor its measurement in patients at high risk of, or with family histories of CVD events. Major lipid-lowering therapies such as statin, fibrates, and ezetimibe have little effect on Lp(a) levels. Therapies such as niacin or cholesterol ester transfer protein (CETP) inhibitors lower Lp(a) as well as reducing other lipid-related risk factors but have failed to clearly reduce CVD events. Proprotein convertase subtilisin kexin-9 (PCSK9) inhibitors reduce cholesterol and Lp(a) as well as reducing CVD events. New antisense therapies specifically targeting apo(a) and hence Lp(a) have greater and more specific effects and will help clarify the extent to which intervention in Lp(a) levels will reduce CVD events.
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Affiliation(s)
- Ahmed Handhle
- Department of Metabolic Medicine/Chemical Pathology, Addenbrookes Hospital, Cambridge, UK
| | - Adie Viljoen
- Department of Metabolic Medicine/Chemical Pathology, North & East Hertfordshire Hospitals Trust, Lister Hospital, Hertfordshire, UK
| | - Anthony S Wierzbicki
- Department of Metabolic Medicine/Chemical Pathology, Guy's & St Thomas', Hospitals, London, SE1 7EH, UK
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Rhainds D, Brodeur MR, Tardif JC. Lipoprotein (a): When to Measure and How to Treat? Curr Atheroscler Rep 2021; 23:51. [PMID: 34235598 DOI: 10.1007/s11883-021-00951-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/03/2021] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW The purpose of this article is to review current evidence for lipoprotein (a) (Lp(a)) as a risk factor for multiple cardiovascular (CV) disease phenotypes, provide a rationale for Lp(a) lowering to reduce CV risk, identify therapies that lower Lp(a) levels that are available clinically and under investigation, and discuss future directions. RECENT FINDINGS Mendelian randomization and epidemiological studies have shown that elevated Lp(a) is an independent and causal risk factor for atherosclerosis and major CV events. Lp(a) is also associated with non-atherosclerotic endpoints such as venous thromboembolism and calcific aortic valve disease. It contributes to residual CV risk in patients receiving standard-of-care LDL-lowering therapy. Plasma Lp(a) levels present a skewed distribution towards higher values and vary widely between individuals and according to ethnic background due to genetic variants in the LPA gene, but remain relatively constant throughout a person's life. Thus, elevated Lp(a) (≥50 mg/dL) is a prevalent condition affecting >20% of the population but is still underdiagnosed. Treatment guidelines have begun to advocate measurement of Lp(a) to identify patients with very high levels that have a family history of premature CVD or elevated Lp(a). Lipoprotein apheresis (LA) efficiently lowers Lp(a) and was recently associated with a reduction of incident CV events. Statins have neutral or detrimental effects on Lp(a), while PCSK9 inhibitors significantly reduce its level by up to 30%. Specific lowering of Lp(a) with antisense oligonucleotides (ASO) shows good safety and strong efficacy with up to 90% reductions. The ongoing CV outcomes study Lp(a)HORIZON will provide a first answer as to whether selective Lp(a) lowering with ASO reduces the risk of major CV events. Given the recently established association between Lp(a) level and CV risk, guidelines now recommend Lp(a) measurement in specific clinical conditions. Accordingly, Lp(a) is a current target for drug development to reduce CV risk in patients with elevated levels, and lowering Lp(a) with ASO represents a promising avenue.
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Affiliation(s)
- David Rhainds
- Montreal Heart Institute Research Center, 5000 Belanger Street, Montréal, Canada
| | - Mathieu R Brodeur
- Montreal Heart Institute Research Center, 5000 Belanger Street, Montréal, Canada
| | - Jean-Claude Tardif
- Montreal Heart Institute Research Center, 5000 Belanger Street, Montréal, Canada. .,Faculty of Medicine, Université de Montréal, Montréal, Canada.
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Lipoprotein(a) the Insurgent: A New Insight into the Structure, Function, Metabolism, Pathogenicity, and Medications Affecting Lipoprotein(a) Molecule. J Lipids 2020; 2020:3491764. [PMID: 32099678 PMCID: PMC7016456 DOI: 10.1155/2020/3491764] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 08/17/2019] [Indexed: 12/15/2022] Open
Abstract
Lipoprotein(a) [Lp(a)], aka “Lp little a”, was discovered in the 1960s in the lab of the Norwegian physician Kåre Berg. Since then, we have greatly improved our knowledge of lipids and cardiovascular disease (CVD). Lp(a) is an enigmatic class of lipoprotein that is exclusively formed in the liver and comprises two main components, a single copy of apolipoprotein (apo) B-100 (apo-B100) tethered to a single copy of a protein denoted as apolipoprotein(a) apo(a). Plasma levels of Lp(a) increase soon after birth to a steady concentration within a few months of life. In adults, Lp(a) levels range widely from <2 to 2500 mg/L. Evidence that elevated Lp(a) levels >300 mg/L contribute to CVD is significant. The improvement of isoform-independent assays, together with the insight from epidemiologic studies, meta-analyses, genome-wide association studies, and Mendelian randomization studies, has established Lp(a) as the single most common independent genetically inherited causal risk factor for CVD. This breakthrough elevated Lp(a) from a biomarker of atherosclerotic risk to a target of therapy. With the emergence of promising second-generation antisense therapy, we hope that we can answer the question of whether Lp(a) is ready for prime-time clinic use. In this review, we present an update on the metabolism, pathophysiology, and current/future medical interventions for high levels of Lp(a).
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Boffa MB, Koschinsky ML. Proprotein convertase subtilisin/kexin type 9 inhibitors and lipoprotein(a)-mediated risk of atherosclerotic cardiovascular disease: more than meets the eye? Curr Opin Lipidol 2019; 30:428-437. [PMID: 31577611 DOI: 10.1097/mol.0000000000000641] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
PURPOSE OF REVIEW Evidence continues to mount for elevated lipoprotein(a) [Lp(a)] as a prevalent, independent, and causal risk factor for atherosclerotic cardiovascular disease. However, the effects of existing lipid-lowering therapies on Lp(a) are comparatively modest and are not specific to Lp(a). Consequently, evidence that Lp(a)-lowering confers a cardiovascular benefit is lacking. Large-scale cardiovascular outcome trials (CVOTs) of inhibitory mAbs targeting proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) may address this issue. RECENT FINDINGS Although the ability of PCSK9i to lower Lp(a) by 15-30% is now clear, the mechanisms involved continue to be debated, with in-vitro and in-vivo studies showing effects on Lp(a) clearance (through the LDL receptor or other receptors) and Lp(a)/apolipoprotein(a) biosynthesis in hepatocytes. The FOURIER CVOT showed that patients with higher baseline levels of Lp(a) derived greater benefit from evolocumab and those with the lowest combined achieved Lp(a) and LDL-cholesterol (LDL-C) had the lowest event rate. Meta-analysis of ten phase 3 trials of alirocumab came to qualitatively similar conclusions concerning achieved Lp(a) levels, although an effect independent of LDL-C lowering could not be demonstrated. SUMMARY Although it is not possible to conclude that PCSK9i specifically lower Lp(a)-attributable risk, patients with elevated Lp(a) could derive incremental benefit from PCSK9i therapy.
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Affiliation(s)
| | - Marlys L Koschinsky
- Department of Physiology & Pharmacology
- Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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Ma L, Chan DC, Ooi EMM, Marcovina SM, Barrett PHR, Watts GF. Apolipoprotein(a) Kinetics in Statin-Treated Patients With Elevated Plasma Lipoprotein(a) Concentration. J Clin Endocrinol Metab 2019; 104:6247-6255. [PMID: 31393573 DOI: 10.1210/jc.2019-01382] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/02/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND Lipoprotein(a) [Lp(a)] is a low-density lipoprotein‒like particle containing apolipoprotein(a) [apo(a)]. Patients with elevated Lp(a), even when treated with statins, are at increased risk of cardiovascular disease. We investigated the kinetic basis for elevated Lp(a) in these patients. OBJECTIVES Apo(a) production rate (PR) and fractional catabolic rate (FCR) were compared between statin-treated patients with and without elevated Lp(a). METHODS The kinetics of apo(a) were investigated in 14 patients with elevated Lp(a) and 15 patients with normal Lp(a) levels matched for age, sex, and body mass index using stable isotope techniques and compartmental modeling. All 29 patients were on background statin treatment. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. RESULTS The plasma concentration and PR of apo(a) were significantly higher in patients with elevated Lp(a) than in patients with normal Lp(a) concentration (all P < 0.01). The FCR of apo(a) was not significantly different between the groups. In univariate analysis, plasma concentration of apo(a) was significantly associated with apo(a) PR in both patient groups (r = 0.699 and r = 0.949, respectively; all P < 0.01). There was no significant association between plasma apo(a) concentration and FCR in either of the groups (r = 0.160 and r = -0.137, respectively). CONCLUSION Elevated plasma Lp(a) concentration is a consequence of increased hepatic production of Lp(a) particles in these patients. Our findings provide a kinetic rationale for the use of therapies that target the synthesis of apo(a) and production of Lp(a) particles in patients with elevated Lp(a).
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Affiliation(s)
- Louis Ma
- School of Biomedical Sciences, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
- School of Medicine, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Dick C Chan
- School of Biomedical Sciences, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
- School of Medicine, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Esther M M Ooi
- School of Biomedical Sciences, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
| | - Santica M Marcovina
- Northwest Lipid Metabolism and Diabetes Research Laboratories, Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington, Seattle, Washington
| | - P Hugh R Barrett
- Faculty of Medicine and Health, University of New England, Armidale, New South Wales, Australia
| | - Gerald F Watts
- School of Medicine, Faculty of Health and Medicine, University of Western Australia, Perth, Western Australia, Australia
- Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Perth, Western Australia, Australia
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Apolipoprotein(a) phenotype determines the correlations of lipoprotein(a) and proprotein convertase subtilisin/kexin type 9 levels in patients with potential familial hypercholesterolemia. Atherosclerosis 2019; 277:477-482. [PMID: 30270088 DOI: 10.1016/j.atherosclerosis.2018.08.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Revised: 06/01/2018] [Accepted: 08/17/2018] [Indexed: 11/24/2022]
Abstract
BACKGROUND AND AIMS The aim of this study is to investigate the relation between lipoprotein(a) [Lp(a)] and proprotein convertase subtilisin/kexin type 9 (PCSK9) concentrations, and their complex, in patients with potential familial hypercholesterolemia (FH), depending on apo(a) phenotype. METHODS The study included 205 patients with total cholesterol (TC) > 7.5 mmol/L and/or low density lipoprotein cholesterol (LDL-C)>4.9 mmol/L, 32 (15%) patients suffered from ischemic heart disease (IHD), 64 were taking statins. The diagnosis of FH was estimated according to the Dutch Lipid Clinics Network criteria. Lipid parameters, apoB-containing lipoprotein subfractions, Lp(a), PCSK9, Lp(a)-PCSK9 complex levels and apo(a) phenotype were determined. Depending on the apo(a) phenotype, all patients were divided into 2 groups: with high molecular weight (HMW) (n = 145) and low molecular weight (LMW) (n = 60) apo(a) phenotype. RESULTS The groups were comparable by all major clinical characteristics and biochemical parameters. In the whole group, PCSK9 concentration correlated with age, statins intake, Lp(a), TC and TG levels. Correlation between Lp(a) and PCSK9 levels was found only in the LMW apo(a) phenotype group independently of statins intake (r = 0.46, p < 0.001). Associations between Lp(a)-PCSK9 complex and large subfractions of intermediate (r = 0.30) and low-density lipoproteins (r = 0.30, p < 0.05 for both) were observed, with more significance in group 2 (r = 0.59, p < 0.005 and r = 0.40, p < 0.05, respectively). CONCLUSIONS In patients with potential familial hypercholesterolemia, positive correlations between concentrations of Lp(a) and PCSK9, as well as of Lp(a)-PCSK9 plasma complex with large subfractions of intermediate and low-density lipoproteins (IDL-1 and LDL-C), were determined by the LMW apo(a) phenotype.
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Ma L, Chan DC, Ooi EMM, Barrett PHR, Watts GF. Fractional turnover of apolipoprotein(a) and apolipoprotein B-100 within plasma lipoprotein(a) particles in statin-treated patients with elevated and normal Lp(a) concentration. Metabolism 2019; 96:8-11. [PMID: 30995439 DOI: 10.1016/j.metabol.2019.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/08/2019] [Accepted: 04/10/2019] [Indexed: 12/31/2022]
Abstract
CONTEXT Lipoprotein(a) [Lp(a)] is a highly atherogenic lipoprotein characterized by apolipoprotein(a) [apo(a)] covalently bounded to apoB-100 (apoB). However, the metabolism of apo(a) and apoB within plasma Lp(a) particles in patients on statins remains unclear. METHODS The kinetics of Lp(a)-apo(a) and Lp(a)-apoB were determined in 20 patients with elevated Lp(a) (≥0.8 g/L; n = 10) and normal Lp(a) (≤0.3 g/L; n = 10) using stable isotope techniques and compartmental modeling. Plasma apo(a) concentration was measured using liquid chromatography-mass spectrometry. All patients were on statin therapy and were studied in the fasting state. RESULTS The fractional catabolic rate (FCR) of Lp(a)-apo(a) was not significantly different from that of Lp(a)-apoB in statin-treated patients with elevated or normal Lp(a) (P > 0.05 in both). Lp(a)-apo(a) FCR was significantly correlated with Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (r = 0.970 and r = 0.979, respectively; all P < 0.001) with Lin's concordance test showing substantial agreement between the FCRs of Lp(a)-apo(a) and Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (rc = 0.978 and rc = 0.966, respectively). CONCLUSION Our data indicate that the apo(a) and apoB proteins within Lp(a) particles have similar FCR and are therefore tightly coupled as an Lp(a) holoparticle in statin-treated patients with elevated and normal Lp(a) concentrations.
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Affiliation(s)
- Louis Ma
- School of Biomedical Sciences, University of Western Australia, Perth, Australia; School of Medicine, University of Western Australia, Perth, Australia
| | - Dick C Chan
- School of Biomedical Sciences, University of Western Australia, Perth, Australia; School of Medicine, University of Western Australia, Perth, Australia
| | - Esther M M Ooi
- School of Biomedical 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
- School of Medicine, University of Western Australia, Perth, Australia; Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Australia.
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19
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Chan DC, Watts GF, Coll B, Wasserman SM, Marcovina SM, Barrett PHR. Lipoprotein(a) Particle Production as a Determinant of Plasma Lipoprotein(a) Concentration Across Varying Apolipoprotein(a) Isoform Sizes and Background Cholesterol-Lowering Therapy. J Am Heart Assoc 2019; 8:e011781. [PMID: 30897995 PMCID: PMC6509712 DOI: 10.1161/jaha.118.011781] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Accepted: 02/12/2019] [Indexed: 12/24/2022]
Abstract
Background Elevated lipoprotein(a) (Lp(a)), a low-density lipoprotein-like particle bound to the polymorphic apolipoprotein(a) (apo(a)), may be causal for cardiovascular disease. However, the metabolism of Lp(a) in humans is poorly understood. Methods and Results We investigated the kinetics of Lp(a)-apo(a) and low-density lipoprotein-apoB-100 in 63 normolipidemic men. The fractional catabolic rate ( FCR ) and production rate PR ) were studied. Plasma apo(a) concentration was significantly and inversely associated with apo(a) isoform size ( r=-0.536, P<0.001) and apo(a) FCR ( r=-0.363, P<0.01), and positively with apo(a) PR ( r=0.877, P<0.001). There were no significant associations between the FCR s of apo(a) and low-density lipoprotein-apoB-100. Subjects with smaller apo(a) isoform sizes (≤22 kringle IV repeats) had significantly higher apo(a) PR ( P<0.05) and lower apo(a) FCR ( P<0.01) than those with larger sizes. Plasma apo(a) concentration was significantly associated with apo(a) PR ( r=0.930, P<0.001), but not with FCR ( r=-0.012, P>0.05) in subjects with smaller apo(a) isoform size. In contrast, both apo(a) PR and FCR were significantly associated with plasma apo(a) concentrations ( r=0.744 and -0.389, respectively, P<0.05) in subjects with larger isoforms. In multiple regression analysis, apo(a) PR and apo(a) isoform size were significant predictors of plasma apo(a) concentration independent of low-density lipoprotein-apoB-100 FCR and background therapy with atorvastatin and evolocumab. Conclusions In normolipidemic men, the plasma Lp(a) concentration is predominantly determined by the rate of production of Lp(a) particles, irrespective of apo(a) isoform size and background therapy with a statin and a proprotein convertase subtilisin-kexin type 9 inhibitor. Our findings underscore the importance of therapeutic targeting of the hepatic synthesis and secretion of Lp(a) particles. Lp(a) particle catabolism may only play a modest role in determining Lp(a) concentration in subjects with larger apo(a) isoform size. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 02189837.
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Affiliation(s)
- Dick C. Chan
- School of MedicineUniversity of Western AustraliaPerthAustralia
- School of Biomedical ScienceUniversity of Western AustraliaPerthAustralia
| | - Gerald F. Watts
- School of MedicineUniversity of Western AustraliaPerthAustralia
- The Lipid Disorders ClinicDepartment of CardiologyRoyal Perth HospitalPerthAustralia
| | | | | | - Santica M. Marcovina
- Northwest Lipid Metabolism and Diabetes Research LaboratoriesDivision of Metabolism, Endocrinology, and NutritionDepartment of MedicineUniversity of WashingtonSeattleWA
| | - P. Hugh R. Barrett
- School of Biomedical ScienceUniversity of Western AustraliaPerthAustralia
- Faculty of Medicine and HealthUniversity of New EnglandArmidaleNew South WalesAustralia
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Borrelli MJ, Youssef A, Boffa MB, Koschinsky ML. New Frontiers in Lp(a)-Targeted Therapies. Trends Pharmacol Sci 2019; 40:212-225. [PMID: 30732864 DOI: 10.1016/j.tips.2019.01.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/13/2022]
Abstract
Interest in lipoprotein (a) [Lp(a)] has exploded over the past decade with the emergence of genetic and epidemiological studies pinpointing elevated levels of this unique lipoprotein as a causal risk factor for atherosclerotic cardiovascular disease (ASCVD) and calcific aortic valve disease (CAVD). This review summarizes the most recent discoveries regarding therapeutic approaches to lower Lp(a) and presents these findings in the context of an emerging, although far from complete, understanding of the biosynthesis and catabolism of Lp(a). Application of Lp(a)-specific lowering agents to outcome trials will be the key to opening this new frontier in the battle against CVD.
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Affiliation(s)
- Matthew J Borrelli
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Amer Youssef
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Michael B Boffa
- Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada; Department of Biochemistry, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada
| | - Marlys L Koschinsky
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada; Robarts Research Institute, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, Ontario, Canada.
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Ma L, Waldmann E, Ooi EMM, Chan DC, Barrett HPR, Watts GF, Parhofer KG. Lipoprotein (a) and Low-density lipoprotein apolipoprotein B metabolism following apheresis in patients with elevated lipoprotein(a) and coronary artery disease. Eur J Clin Invest 2019; 49:e13053. [PMID: 30447089 DOI: 10.1111/eci.13053] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 11/04/2018] [Accepted: 11/13/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND Lipoprotein apheresis effectively lowers lipoprotein(a) [Lp(a)] and low-density lipoprotein (LDL) by approximately 60%-70%. The rebound of LDL and Lp(a) particle concentrations following lipoprotein apheresis allows the determination of fractional catabolic rate (FCR) and hence production rate (PR) during non-steady state conditions. We aimed to investigate the kinetics of Lp(a) and LDL apolipoprotein B-100 (apoB) particles in patients with elevated Lp(a) and coronary artery disease undergoing regular apheresis. PATIENTS AND METHODS A cross-sectional study was carried out in 13 patients with elevated Lp(a) concentration (>500 mg/L) and coronary artery disease. Lp(a) and LDL-apoB metabolic parameters, including FCR and PR were derived by the fit of a compartment model to the Lp(a) and LDL-apoB concentration data following lipoprotein apheresis. RESULTS The FCR of Lp(a) was significantly lower than that of LDL-apoB (0.39 [0.31, 0.49] vs 0.57 [0.46, 0.71] pools/day, P = 0.03) with no significant differences in the corresponding PR (14.80 [11.34, 19.32] vs 15.73 [11.93, 20.75] mg/kg/day, P = 0.80). No significant associations were observed between the FCR and PR of Lp(a) and LDL-apoB. CONCLUSIONS In patients with elevated Lp(a), the fractional catabolism of Lp(a) is slower than that of LDL-apoB particles, implying that different metabolic pathways are involved in the catabolism of these lipoproteins. These findings have implications for new therapies for lowering apolipoprotein(a) and apoB to prevent atherosclerotic cardiovascular disease.
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Affiliation(s)
- Louis Ma
- School of Biomedical Science, University of Western Australia, Western Australia, Australia.,School of Medicine, University of Western Australia, Western Australia, Australia
| | - Elisa Waldmann
- Department of Internal Medicine IV, Ludwig-Maximilans-University Munich, Munich, Germany
| | - Esther M M Ooi
- School of Biomedical Science, University of Western Australia, Western Australia, Australia
| | - Dick C Chan
- School of Biomedical Science, University of Western Australia, Western Australia, Australia.,School of Medicine, University of Western Australia, Western Australia, Australia
| | - Hugh P R Barrett
- School of Biomedical Science, University of Western Australia, Western Australia, Australia
| | - Gerald F Watts
- School of Medicine, University of Western Australia, Western Australia, Australia.,Department of Cardiology, Lipid Disorders Clinic, Royal Perth Hospital, Western Australia, Australia
| | - Klaus G Parhofer
- Department of Internal Medicine IV, Ludwig-Maximilans-University Munich, Munich, Germany
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Boffa MB, Koschinsky ML. Oxidized phospholipids as a unifying theory for lipoprotein(a) and cardiovascular disease. Nat Rev Cardiol 2019; 16:305-318. [DOI: 10.1038/s41569-018-0153-2] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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23
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McCormick SPA, Schneider WJ. Lipoprotein(a) catabolism: a case of multiple receptors. Pathology 2018; 51:155-164. [PMID: 30595508 DOI: 10.1016/j.pathol.2018.11.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 01/09/2023]
Abstract
Lipoprotein(a) [Lp(a)] is an apolipoprotein B (apoB)-containing plasma lipoprotein similar in structure to low-density lipoprotein (LDL). Lp(a) is more complex than LDL due to the presence of apolipoprotein(a) [apo(a)], a large glycoprotein sharing extensive homology with plasminogen, which confers some unique properties onto Lp(a) particles. ApoB and apo(a) are essential for the assembly and catabolism of Lp(a); however, other proteins associated with the particle may modify its metabolism. Lp(a) specifically carries a cargo of oxidised phospholipids (OxPL) bound to apo(a) which stimulates many proinflammatory pathways in cells of the arterial wall, a key property underlying its pathogenicity and association with cardiovascular disease (CVD). While the liver and kidney are the major tissues implicated in Lp(a) clearance, the pathways for Lp(a) uptake appear to be complex and are still under investigation. Biochemical studies have revealed an exceptional array of receptors that associate with Lp(a) either via its apoB, apo(a), or OxPL components. These receptors fall into five main categories, namely 'classical' lipoprotein receptors, toll-like and scavenger receptors, lectins, and plasminogen receptors. The roles of these receptors have largely been dissected by genetic manipulation in cells or mice, although their relative physiological importance for removal of Lp(a) from the circulation remains unclear. The LPA gene encoding apo(a) has an overwhelming effect on Lp(a) levels which precludes any clear associations between potential Lp(a) receptor genes and Lp(a) levels in population studies. Targeted approaches and the selection of unique Lp(a) phenotypes within populations has nevertheless allowed for some associations to be made. Few of the proposed Lp(a) receptors can specifically be manipulated with current drugs and, as such, it is not currently clear whether any of these receptors could provide relevant targets for therapeutic manipulation of Lp(a) levels. This review summarises the current status of knowledge about receptor-mediated pathways for Lp(a) catabolism.
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Affiliation(s)
- Sally P A McCormick
- Department of Biochemistry, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
| | - Wolfgang J Schneider
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
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Kostner KM, Kostner GM, Wierzbicki AS. Is Lp(a) ready for prime time use in the clinic? A pros-and-cons debate. Atherosclerosis 2018; 274:16-22. [PMID: 29747086 DOI: 10.1016/j.atherosclerosis.2018.04.032] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/16/2018] [Accepted: 04/25/2018] [Indexed: 12/11/2022]
Abstract
Lipoprotein (a) (Lp(a)) is a cholesterol-rich lipoprotein known since 1963. In spite of extensive research on Lp(a), there are still numerous gaps in our knowledge relating to its function, biosynthesis and catabolism. One reason for this might be that apo(a), the characteristic glycoprotein of Lp(a), is expressed only in primates. Results from experiments using transgenic animals therefore may need verification in humans. Studies on Lp(a) are also handicapped by the great number of isoforms of apo(a) and the heterogeneity of apo(a)-containing fractions in plasma. Quantification of Lp(a) in the clinical laboratory for a long time has not been standardized. Starting from its discovery, reports accumulated that Lp(a) contributed to the risk of cardiovascular disease (CVD), myocardial infarction (MI) and stroke. Early reports were based on case control studies but in the last decades a great deal of prospective studies have been published that highlight the increased risk for CVD and MI in patients with elevated Lp(a). Final answers to the question of whether Lp(a) is ready for wider clinical use will come from intervention studies with novel selective Lp(a) lowering medications that are currently underway. This article expounds arguments for and against this proposition from currently available data.
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Affiliation(s)
- Karam M Kostner
- Department of Cardiology, Mater Hospital and University of Queensland, Brisbane, Australia
| | - Gert M Kostner
- Department of Molecular Biology and Biochemistry, Gottfried Schatz Research Center for Cell Signaling, Medical University of Graz, Austria
| | - Anthony S Wierzbicki
- Department of Metabolic Medicine/Chemical Pathology, Guy's & St Thomas' Hospitals, London, UK.
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Boffa MB, Koschinsky ML. The journey towards understanding lipoprotein(a) and cardiovascular disease risk: are we there yet? Curr Opin Lipidol 2018. [PMID: 29528858 DOI: 10.1097/mol.0000000000000499] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE OF REVIEW Evidence continues to mount for an important role for elevated plasma concentrations of lipoprotein(a) [Lp(a)] in mediating risk of atherothrombotic and calcific aortic valve diseases. However, there continues to be great uncertainty regarding some basic aspects of Lp(a) biology including its biosynthesis and catabolism, its mechanisms of action in health and disease, and the significance of its isoform size heterogeneity. Moreover, the precise utility of Lp(a) in the clinic remains undefined. RECENT FINDINGS The contribution of elevated Lp(a) to cardiovascular risk continues to be more precisely defined by larger studies. In particular, the emerging role of Lp(a) as a potent risk factor for calcific aortic valve disease has received much scrutiny. Mechanistic studies have identified commonalities underlying the impact of Lp(a) on atherosclerosis and aortic valve disease, most notably related to Lp(a)-associated oxidized phospholipids. The mechanisms governing Lp(a) concentrations remain a source of considerable dispute. SUMMARY This article highlights some key remaining challenges in understanding Lp(a) actions and clinical significance. Most important in this regard is demonstration of a beneficial effect of lowering Lp(a), a development that is on the horizon as effective Lp(a)-lowering therapies are being tested in the clinic.
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Affiliation(s)
| | - Marlys L Koschinsky
- Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Ontario, Canada
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Watts GF, Chan DC, Somaratne R, Wasserman SM, Scott R, Marcovina SM, Barrett PHR. Controlled study of the effect of proprotein convertase subtilisin-kexin type 9 inhibition with evolocumab on lipoprotein(a) particle kinetics. Eur Heart J 2018; 39:2577-2585. [DOI: 10.1093/eurheartj/ehy122] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 03/02/2018] [Indexed: 12/24/2022] Open
Affiliation(s)
- Gerald F Watts
- Lipid Disorders Clinic, Department of Cardiology, Royal Perth Hospital, Perth, WA, Australia
- Schools of Medicine and Biomedical Science, University of Western Australia, Perth, WA, Australia
| | - Dick C Chan
- Schools of Medicine and Biomedical Science, University of Western Australia, Perth, WA, Australia
| | | | | | - Rob Scott
- Formerly of Amgen, Inc., Thousand Oaks, CA, USA
| | - Santica M Marcovina
- Northwest Lipid Metabolism and Diabetes Research Laboratories, Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington, Seattle, WA, USA
| | - P Hugh R Barrett
- Schools of Medicine and Biomedical Science, University of Western Australia, Perth, WA, Australia
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Scipione CA, Koschinsky ML, Boffa MB. Lipoprotein(a) in clinical practice: New perspectives from basic and translational science. Crit Rev Clin Lab Sci 2017; 55:33-54. [PMID: 29262744 DOI: 10.1080/10408363.2017.1415866] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Elevated plasma concentrations of lipoprotein(a) (Lp(a)) are a causal risk factor for coronary heart disease (CHD) and calcific aortic valve stenosis (CAVS). Genetic, epidemiological and in vitro data provide strong evidence for a pathogenic role for Lp(a) in the progression of atherothrombotic disease. Despite these advancements and a race to develop new Lp(a) lowering therapies, there are still many unanswered and emerging questions about the metabolism and pathophysiology of Lp(a). New studies have drawn attention to Lp(a) as a contributor to novel pathogenic processes, yet the mechanisms underlying the contribution of Lp(a) to CVD remain enigmatic. New therapeutics show promise in lowering plasma Lp(a) levels, although the complete mechanisms of Lp(a) lowering are not fully understood. Specific agents targeted to apolipoprotein(a) (apo(a)), namely antisense oligonucleotide therapy, demonstrate potential to decrease Lp(a) to levels below the 30-50 mg/dL (75-150 nmol/L) CVD risk threshold. This therapeutic approach should aid in assessing the benefit of lowering Lp(a) in a clinical setting.
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Affiliation(s)
- Corey A Scipione
- a Department of Advanced Diagnostics , Toronto General Hospital Research Institute, UHN , Toronto , Canada
| | - Marlys L Koschinsky
- b Robarts Research Institute , Western University , London , Canada.,c Department of Physiology & Pharmacology , Schulich School of Medicine & Dentistry, Western University , London , Canada
| | - Michael B Boffa
- d Department of Biochemistry , Western University , London , Canada
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Ellis KL, Boffa MB, Sahebkar A, Koschinsky ML, Watts GF. The renaissance of lipoprotein(a): Brave new world for preventive cardiology? Prog Lipid Res 2017; 68:57-82. [DOI: 10.1016/j.plipres.2017.09.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 09/01/2017] [Accepted: 09/05/2017] [Indexed: 12/24/2022]
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Boffa MB. Emerging Therapeutic Options for Lowering of Lipoprotein(a): Implications for Prevention of Cardiovascular Disease. Curr Atheroscler Rep 2017; 18:69. [PMID: 27761705 DOI: 10.1007/s11883-016-0622-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Elevated plasma concentrations of lipoprotein(a) (Lp(a)) are an independent and causal risk factor for cardiovascular diseases including coronary artery disease, ischemic stroke, and calcific aortic valve stenosis. This review summarizes the rationale for Lp(a) lowering and surveys relevant clinical trial data using a variety of agents capable of lowering Lp(a). RECENT FINDINGS Contemporary guidelines and recommendations outline populations of patients who should be screened for elevated Lp(a) and who might benefit from Lp(a) lowering. Therapies including drugs and apheresis have been described that lower Lp(a) levels modestly (∼20 %) to dramatically (∼80 %). Existing therapies that lower Lp(a) also have beneficial effects on other aspects of the lipid profile, with the exception of Lp(a)-specific apheresis and an antisense oligonucleotide that targets the mRNA encoding apolipoprotein(a). No clinical trials conducted to date have managed to answer the key question of whether Lp(a) lowering confers a benefit in terms of ameliorating cardiovascular risk, although additional outcome trials of therapies that lower Lp(a) are ongoing. It is more likely, however, that Lp(a)-specific agents will provide the most appropriate approach for addressing this question.
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Affiliation(s)
- Michael B Boffa
- Department of Biochemistry, Room 4245A Robarts Research Institute, University of Western Ontario, 1151 Richmond Street North, London, ON, Canada, N6A 5B7.
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Thomas T, Zhou H, Karmally W, Ramakrishnan R, Holleran S, Liu Y, Jumes P, Wagner JA, Hubbard B, Previs SF, Roddy T, Johnson-Levonas AO, Gutstein DE, Marcovina SM, Rader DJ, Ginsberg HN, Millar JS, Reyes-Soffer G. CETP (Cholesteryl Ester Transfer Protein) Inhibition With Anacetrapib Decreases Production of Lipoprotein(a) in Mildly Hypercholesterolemic Subjects. Arterioscler Thromb Vasc Biol 2017; 37:1770-1775. [PMID: 28729361 PMCID: PMC5567403 DOI: 10.1161/atvbaha.117.309549] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 07/04/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Lp(a) [lipoprotein (a)] is composed of apoB (apolipoprotein B) and apo(a) [apolipoprotein (a)] and is an independent risk factor for cardiovascular disease and aortic stenosis. In clinical trials, anacetrapib, a CETP (cholesteryl ester transfer protein) inhibitor, causes significant reductions in plasma Lp(a) levels. We conducted an exploratory study to examine the mechanism for Lp(a) lowering by anacetrapib. APPROACH AND RESULTS We enrolled 39 participants in a fixed-sequence, double-blind study of the effects of anacetrapib on the metabolism of apoB and high-density lipoproteins. Twenty-nine patients were randomized to atorvastatin 20 mg/d, plus placebo for 4 weeks, and then atorvastatin plus anacetrapib (100 mg/d) for 8 weeks. The other 10 subjects were randomized to double placebo for 4 weeks followed by placebo plus anacetrapib for 8 weeks. We examined the mechanisms of Lp(a) lowering in a subset of 12 subjects having both Lp(a) levels >20 nmol/L and more than a 15% reduction in Lp(a) by the end of anacetrapib treatment. We performed stable isotope kinetic studies using 2H3-leucine at the end of each treatment to measure apo(a) fractional catabolic rate and production rate. Median baseline Lp(a) levels were 21.5 nmol/L (interquartile range, 9.9-108.1 nmol/L) in the complete cohort (39 subjects) and 52.9 nmol/L (interquartile range, 38.4-121.3 nmol/L) in the subset selected for kinetic studies. Anacetrapib treatment lowered Lp(a) by 34.1% (P≤0.001) and 39.6% in the complete and subset cohort, respectively. The decreases in Lp(a) levels were because of a 41% reduction in the apo(a) production rate, with no effects on apo(a) fractional catabolic rate. CONCLUSIONS Anacetrapib reduces Lp(a) levels by decreasing its production. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00990808.
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Affiliation(s)
- Tiffany Thomas
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Haihong Zhou
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Wahida Karmally
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Rajasekhar Ramakrishnan
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Stephen Holleran
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Yang Liu
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Patricia Jumes
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - John A Wagner
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Brian Hubbard
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Stephen F Previs
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Thomas Roddy
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Amy O Johnson-Levonas
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - David E Gutstein
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Santica M Marcovina
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Daniel J Rader
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Henry N Ginsberg
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - John S Millar
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.)
| | - Gissette Reyes-Soffer
- From the Columbia University, New York (T.T., W.K., R.R., S.H., H.N.G., G.R.-S.); Merck & Co, Inc, Kenilworth, NJ (H.Z., Y.L., P.J., J.A.W., B.H., S.F.P., T.R., A.O.J.-L., D.E.G.); University of Washington, Seattle (S.M.M.); and University of Pennsylvania, Philadelphia (D.J.R., J.S.M.).
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Reyes-Soffer G, Ginsberg HN, Ramakrishnan R. The metabolism of lipoprotein (a): an ever-evolving story. J Lipid Res 2017; 58:1756-1764. [PMID: 28720561 DOI: 10.1194/jlr.r077693] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 07/18/2017] [Indexed: 02/06/2023] Open
Abstract
Lipoprotein (a) [Lp(a)] is characterized by apolipoprotein (a) [apo(a)] covalently bound to apolipoprotein B 100. It was described in human plasma by Berg et al. in 1963 and the gene encoding apo(a) (LPA) was cloned in 1987 by Lawn and colleagues. Epidemiologic and genetic studies demonstrate that increases in Lp(a) plasma levels increase the risk of atherosclerotic cardiovascular disease. Novel Lp(a) lowering treatments highlight the need to understand the regulation of plasma levels of this atherogenic lipoprotein. Despite years of research, significant uncertainty remains about the assembly, secretion, and clearance of Lp(a). Specifically, there is ongoing controversy about where apo(a) and apoB-100 bind to form Lp(a); which apoB-100 lipoproteins bind to apo(a) to create Lp(a); whether binding of apo(a) is reversible, allowing apo(a) to bind to more than one apoB-100 lipoprotein during its lifespan in the circulation; and how Lp(a) or apo(a) leave the circulation. In this review, we highlight past and recent data from stable isotope studies of Lp(a) metabolism, highlighting the critical metabolic uncertainties that exist. We present kinetic models to describe results of published studies using stable isotopes and suggest what future studies are required to improve our understanding of Lp(a) metabolism.
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Affiliation(s)
- Gissette Reyes-Soffer
- Departments of Medicine Columbia University College of Physicians and Surgeons, New York, NY 10032
| | - Henry N Ginsberg
- Departments of Medicine Columbia University College of Physicians and Surgeons, New York, NY 10032
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Moriarty PM, Varvel SA, Gordts PLSM, McConnell JP, Tsimikas S. Lipoprotein(a) Mass Levels Increase Significantly According to APOE Genotype: An Analysis of 431 239 Patients. Arterioscler Thromb Vasc Biol 2017; 37:580-588. [PMID: 28062489 DOI: 10.1161/atvbaha.116.308704] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 12/21/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Lipoprotein(a) [Lp(a)] levels are genetically determined by hepatocyte apolipoprotein(a) synthesis, but catabolic pathways also influence circulating levels. APOE genotypes have different affinities for the low-density lipoprotein (LDL) receptor and LDL-related protein-1, with ε2 having the weakest binding to LDL receptor at <2% relative to ε3 and ε4. APPROACH AND RESULTS: APOE genotypes (ε2/ε2, ε2/ε3, ε2/ε4, ε3/ε3, ε3/ε4, and ε4/ε4), Lp(a) mass, directly measured Lp(a)-cholesterol levels, and a variety of apoB-related lipoproteins were measured in 431 239 patients. The prevalence of APOE traits were ε2: 7.35%, ε3: 77.56%, and ε4: 15.09%. Mean (SD) Lp(a) levels were 65% higher in ε4/ε4 compared with ε2/ε2 genotypes and increased significantly according to APOE genotype: ε2/ε2: 23.4 (29.2), ε2/ε3: 31.3 (38.0), ε2/ε4: 32.8 (38.5), ε3/ε3: 33.2 (39.1), ε3/ε4: 35.5 (41.6), and ε4/ε4: 38.5 (44.1) mg/dL (P<0.0001). LDL-cholesterol, apoB, Lp(a)-cholesterol, LDL-cholesterol corrected for Lp(a)-cholesterol content, LDL-particle number, and small, dense LDL also had similar patterns. Patients with LDL-cholesterol ≥250 mg/dL, who are more likely to have LDL receptor mutations and reduced affinity for apoB, had higher Lp(a) levels across all apoE isoforms, but particularly in patients with ε2 alleles, compared with LDL <250 mg/dL. The lowest Lp(a) mass levels were present in patients with ε2 isoforms and lowest LDL-cholesterol. CONCLUSIONS APOE genotypes strongly influence Lp(a) and apoB-related lipoprotein levels. This suggests that differences in affinity of apoE proteins for lipoprotein clearance receptors may affect Lp(a) catabolism, suggesting a competition between Lp(a) and apoE protein for similar receptors.
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Affiliation(s)
- Patrick M Moriarty
- From the Division of Clinical Pharmacology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City (P.M.M.); Salveo Diagnostics, Inc, Richmond, VA (S.A.V., J.P.M.); Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center (P.L.S.M.G.), Department of Medicine, Division of Endocrinology and Metabolism (P.L.S.M.G.), and Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center (S.T.), University of California San Diego, La Jolla
| | - Stephen A Varvel
- From the Division of Clinical Pharmacology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City (P.M.M.); Salveo Diagnostics, Inc, Richmond, VA (S.A.V., J.P.M.); Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center (P.L.S.M.G.), Department of Medicine, Division of Endocrinology and Metabolism (P.L.S.M.G.), and Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center (S.T.), University of California San Diego, La Jolla
| | - Philip L S M Gordts
- From the Division of Clinical Pharmacology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City (P.M.M.); Salveo Diagnostics, Inc, Richmond, VA (S.A.V., J.P.M.); Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center (P.L.S.M.G.), Department of Medicine, Division of Endocrinology and Metabolism (P.L.S.M.G.), and Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center (S.T.), University of California San Diego, La Jolla
| | - Joseph P McConnell
- From the Division of Clinical Pharmacology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City (P.M.M.); Salveo Diagnostics, Inc, Richmond, VA (S.A.V., J.P.M.); Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center (P.L.S.M.G.), Department of Medicine, Division of Endocrinology and Metabolism (P.L.S.M.G.), and Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center (S.T.), University of California San Diego, La Jolla
| | - Sotirios Tsimikas
- From the Division of Clinical Pharmacology, Department of Internal Medicine, University of Kansas Medical Center, Kansas City (P.M.M.); Salveo Diagnostics, Inc, Richmond, VA (S.A.V., J.P.M.); Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center (P.L.S.M.G.), Department of Medicine, Division of Endocrinology and Metabolism (P.L.S.M.G.), and Division of Cardiovascular Medicine, Sulpizio Cardiovascular Center (S.T.), University of California San Diego, La Jolla.
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Sharma M, Redpath GM, Williams MJA, McCormick SPA. Recycling of Apolipoprotein(a) After PlgRKT-Mediated Endocytosis of Lipoprotein(a). Circ Res 2016; 120:1091-1102. [PMID: 28003220 DOI: 10.1161/circresaha.116.310272] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/15/2016] [Accepted: 12/21/2016] [Indexed: 11/16/2022]
Abstract
RATIONALE Lipoprotein(a) [Lp(a)] is a low-density lipoprotein-like lipoprotein and important cardiovascular risk factor whose cognate receptor and intracellular fate remains unknown. OBJECTIVE Our study aimed to determine the intracellular trafficking pathway for Lp(a) and the receptor responsible for its uptake in liver cells. METHODS AND RESULTS Human hepatoma cells were treated with Lp(a) purified from human plasma and Lp(a) uptake studied using Western blot analysis and intracellular localization of Lp(a) by confocal microscopy. Lp(a) was maximally internalized by 2 hours and was detected by an antiapo(a) antibody to be localized to Rab5-positive early endosomes, the trans-Golgi network, and subsequently Rab11-positive recycling endosomes. In human hepatoma cells, the apo(a) component from the internalized Lp(a) was resecreted back into the cellular media, whereas the low-density lipoprotein component was localized to the lysosomal compartment. Lp(a) internalization was reduced 0.35-fold in HAP1 and 0.33-fold in human hepatoma cells in which the plasminogen receptor (KT) was knocked out. Conversely, Lp(a) internalization was enhanced 2-fold in HAP1 and 1.6-fold in human hepatoma cells in which plasminogen receptor (KT) was overexpressed, showing for the first time the role of a specific plasminogen receptor in Lp(a) uptake. CONCLUSIONS The novel findings that Lp(a) is internalized by the plasminogen receptor, plasminogen receptor (KT), and the apo(a) component is recycled may have important implications for the catabolism and function of Lp(a).
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Affiliation(s)
- Monika Sharma
- From the Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand (M.S., G.M.R., S.P.A.M.); and Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand (M.J.A.W.)
| | - Gregory M Redpath
- From the Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand (M.S., G.M.R., S.P.A.M.); and Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand (M.J.A.W.)
| | - Michael J A Williams
- From the Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand (M.S., G.M.R., S.P.A.M.); and Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand (M.J.A.W.)
| | - Sally P A McCormick
- From the Department of Biochemistry, Otago School of Medical Sciences, University of Otago, Dunedin, New Zealand (M.S., G.M.R., S.P.A.M.); and Department of Medicine, Dunedin School of Medicine, University of Otago, New Zealand (M.J.A.W.).
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Reyes-Soffer G, Pavlyha M, Ngai C, Thomas T, Holleran S, Ramakrishnan R, Karmally W, Nandakumar R, Fontanez N, Obunike J, Marcovina SM, Lichtenstein AH, Matthan NR, Matta J, Maroccia M, Becue F, Poitiers F, Swanson B, Cowan L, Sasiela WJ, Surks HK, Ginsberg HN. Effects of PCSK9 Inhibition With Alirocumab on Lipoprotein Metabolism in Healthy Humans. Circulation 2016; 135:352-362. [PMID: 27986651 PMCID: PMC5262523 DOI: 10.1161/circulationaha.116.025253] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 12/07/2016] [Indexed: 12/02/2022]
Abstract
Supplemental Digital Content is available in the text. Background: Alirocumab, a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 (PCSK9), lowers plasma low-density lipoprotein (LDL) cholesterol and apolipoprotein B100 (apoB). Although studies in mice and cells have identified increased hepatic LDL receptors as the basis for LDL lowering by PCSK9 inhibitors, there have been no human studies characterizing the effects of PCSK9 inhibitors on lipoprotein metabolism. In particular, it is not known whether inhibition of PCSK9 has any effects on very low-density lipoprotein or intermediate-density lipoprotein (IDL) metabolism. Inhibition of PCSK9 also results in reductions of plasma lipoprotein (a) levels. The regulation of plasma Lp(a) levels, including the role of LDL receptors in the clearance of Lp(a), is poorly defined, and no mechanistic studies of the Lp(a) lowering by alirocumab in humans have been published to date. Methods: Eighteen (10 F, 8 mol/L) participants completed a placebo-controlled, 2-period study. They received 2 doses of placebo, 2 weeks apart, followed by 5 doses of 150 mg of alirocumab, 2 weeks apart. At the end of each period, fractional clearance rates (FCRs) and production rates (PRs) of apoB and apo(a) were determined. In 10 participants, postprandial triglycerides and apoB48 levels were measured. Results: Alirocumab reduced ultracentrifugally isolated LDL-C by 55.1%, LDL-apoB by 56.3%, and plasma Lp(a) by 18.7%. The fall in LDL-apoB was caused by an 80.4% increase in LDL-apoB FCR and a 23.9% reduction in LDL-apoB PR. The latter was due to a 46.1% increase in IDL-apoB FCR coupled with a 27.2% decrease in conversion of IDL to LDL. The FCR of apo(a) tended to increase (24.6%) without any change in apo(a) PR. Alirocumab had no effects on FCRs or PRs of very low-density lipoproteins-apoB and very low-density lipoproteins triglycerides or on postprandial plasma triglycerides or apoB48 concentrations. Conclusions: Alirocumab decreased LDL-C and LDL-apoB by increasing IDL- and LDL-apoB FCRs and decreasing LDL-apoB PR. These results are consistent with increases in LDL receptors available to clear IDL and LDL from blood during PCSK9 inhibition. The increase in apo(a) FCR during alirocumab treatment suggests that increased LDL receptors may also play a role in the reduction of plasma Lp(a). Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01959971.
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Affiliation(s)
- Gissette Reyes-Soffer
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.).
| | - Marianna Pavlyha
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Colleen Ngai
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Tiffany Thomas
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Stephen Holleran
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Rajasekhar Ramakrishnan
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Wahida Karmally
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Renu Nandakumar
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Nelson Fontanez
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Joseph Obunike
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Santica M Marcovina
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Alice H Lichtenstein
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Nirupa R Matthan
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - James Matta
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Magali Maroccia
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Frederic Becue
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Franck Poitiers
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Brian Swanson
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Lisa Cowan
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - William J Sasiela
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Howard K Surks
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.)
| | - Henry N Ginsberg
- From Columbia University College of Physicians and Surgeons, New York (G.R.-S., M.P., C.N., T.T., S.H., R.R., W.K., R.N., N.F., H.N.G.); The City University of New York (J.O.); Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle (S.M.M.); Cardiovascular Nutrition Laboratory, JM USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA (A.H.L., N.R.M.); Sanofi, Bridgewater, NJ (J.M., B.S., L.C., H.K.S.); Umanis, Levallois-Perret, France (M.M.); Sanofi, Montpellier, France (F.B.); Sanofi, Paris, France (F.P.); and Regeneron Pharmaceuticals, Inc., Tarrytown, NY (W.J.S.).
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SRM-based measurements of proprotein convertase subtilisin/kexin type 9 and lipoprotein(a) kinetics in nonhuman primate serum. Bioanalysis 2016; 8:2551-2563. [DOI: 10.4155/bio-2016-0146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aim: PCSK9 and Lp(a) have been identified as potential biomarkers for cardiovascular disease. The ability to measure protein turnover rates will provide insights into the dynamic properties of these proteins and lead to better understanding of their biological roles. We aimed to implement the stable isotope-labeled tracers ([2H3]-leucine) and develop a novel LC-selected reaction monitoring (SRM) mass spectrometry (MS) method to study the kinetics of PCSK9 and Lp(a). Results: A sensitive method using immunoaffinity enrichment coupled with LC-SRM MS was developed to measure the production and degradation rates of PCSK9 and Lp(a) in naive nonhuman primate serum. Comparable results were obtained from two different routes of tracer administration. Conclusion: Immunoaffinity enrichment coupled with LC-SRM MS demonstrated success in in vivo kinetic measurements of proteins with relatively slow turnover rate (Lp[a]) or low abundance (PCSK9) in serum.
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Kostner KM, Kostner GM. Lipoprotein (a): a historical appraisal. J Lipid Res 2016; 58:1-14. [PMID: 27821413 DOI: 10.1194/jlr.r071571] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 11/01/2016] [Indexed: 11/20/2022] Open
Abstract
Initially, lipoprotein (a) [Lp(a)] was believed to be a genetic variant of lipoprotein (Lp)-B. Because its lipid moiety is almost identical to LDL, Lp(a) has been deliberately considered to be highly atherogenic. Lp(a) was detected in 1963 by Kare Berg, and individuals who were positive for this factor were called Lpa+ Lpa+ individuals were found more frequently in patients with coronary heart disease than in controls. After the introduction of quantitative methods for monitoring of Lp(a), it became apparent that Lp(a), in fact, is present in all individuals, yet to a greatly variable extent. The genetics of Lp(a) had been a mystery for a long time until Gerd Utermann discovered that apo(a) is expressed by a variety of alleles, giving rise to a unique size heterogeneity. This size heterogeneity, as well as countless mutations, is responsible for the great variability in plasma Lp(a) concentrations. Initially, we proposed to evaluate the risk of myocardial infarction at a cut-off for Lp(a) of 30-50 mg/dl, a value that still is adopted in numerous epidemiological studies. Due to new therapies that lower Lp(a) levels, there is renewed interest and still rising research activity in Lp(a). Despite all these activities, numerous gaps exist in our knowledge, especially as far as the function and metabolism of this fascinating Lp are concerned.
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Affiliation(s)
- Karam M Kostner
- Department of Cardiology, Mater Hospital and University of Queensland, Brisbane, 4101 Queensland, Australia
| | - Gert M Kostner
- Institute of Molecular Biology and Biochemistry, Medical University of Graz, A-8010 Graz, Austria
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37
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Diffenderfer MR, Lamon-Fava S, Marcovina SM, Barrett PHR, Lel J, Dolnikowski GG, Berglund L, Schaefer EJ. Distinct metabolism of apolipoproteins (a) and B-100 within plasma lipoprotein(a). Metabolism 2016; 65:381-90. [PMID: 26975530 PMCID: PMC4795479 DOI: 10.1016/j.metabol.2015.10.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/28/2015] [Accepted: 10/31/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Lipoprotein(a) [Lp(a)] is mainly similar in composition to LDL, but differs in having apolipoprotein (apo) (a) covalently linked to apoB-100. Our purpose was to examine the individual metabolism of apo(a) and apoB-100 within plasma Lp(a). MATERIALS AND METHODS The kinetics of apo(a) and apoB-100 in plasma Lp(a) were assessed in four men with dyslipidemia [Lp(a) concentration: 8.9-124.7nmol/L]. All subjects received a primed constant infusion of [5,5,5-(2)H3] L-leucine while in the constantly fed state. Lp(a) was immunoprecipitated directly from whole plasma; apo(a) and apoB-100 were separated by gel electrophoresis; and isotopic enrichment was determined by gas chromatography/mass spectrometry. RESULTS Multicompartmental modeling analysis indicated that the median fractional catabolic rates of apo(a) and apoB-100 within Lp(a) were significantly different at 0.104 and 0.263 pools/day, respectively (P=0.04). The median Lp(a) apo(a) production rate at 0.248nmol/kg·day(-1) was significantly lower than that of Lp(a) apoB-100 at 0.514nmol/kg·day(-1) (P=0.03). CONCLUSION Our data indicate that apo(a) has a plasma residence time (11days) that is more than twice as long as that of apoB-100 (4days) within Lp(a), supporting the concept that apo(a) and apoB-100 within plasma Lp(a) are not catabolized from the bloodstream as a unit in humans in the fed state.
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Affiliation(s)
- Margaret R Diffenderfer
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
| | - Stefania Lamon-Fava
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
| | - Santica M Marcovina
- Northwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, 401 Queen Anne Avenue North, Seattle, WA 98109, USA.
| | - P Hugh R Barrett
- School of Medicine and Pharmacology and Faculty of Engineering, Computing and Mathematics, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia.
| | - Julian Lel
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
| | - Gregory G Dolnikowski
- Mass Spectrometry Unit, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
| | - Lars Berglund
- Clinical and Translational Science Center, University of California, Davis, 2921 Stockton Boulevard, Suite 1400, Sacramento, CA 95817, USA.
| | - Ernst J Schaefer
- Cardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA 02111, USA.
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Croyal M, Fall F, Ferchaud-Roucher V, Chétiveaux M, Zaïr Y, Ouguerram K, Krempf M, Nobécourt E. Multiplexed peptide analysis for kinetic measurements of major human apolipoproteins by LC/MS/MS. J Lipid Res 2016; 57:509-15. [PMID: 26773160 DOI: 10.1194/jlr.d064618] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2015] [Indexed: 11/20/2022] Open
Abstract
A multiplexed assay was developed by MS to analyze, in a single run, six major human Apos involved in lipoprotein metabolism: ApoA-I, ApoA-II, ApoB100, ApoC-II, ApoC-III, and ApoE. This method was validated in vivo in six subjects who received a 14 h constant infusion of [5,5,5-(2)H3]L-leucine at 10 μM/kg/h. Plasma lipoprotein fractions were isolated from collected blood samples and were digested with trypsin. Proteotypic peptides were subsequently analyzed by LC/MS/MS. Enrichment measurement data were compared with those obtained by the standard method using GC/MS. The required time to obtain the LC/MS/MS data was less than that needed for GC/MS. The enrichments from both methods were correlated for ApoA-I (r = 0.994; P < 0.0001) and ApoB100 (r = 0.999; P < 0.0001), and the Bland-Altman plot confirmed the similarity of the two methods. Intra- and inter-assay variability calculated for the six Apos of interest did not exceed 10.7 and 12.5%, respectively, and kinetic parameters were similar and/or in agreement with previously reported data. Therefore, LC/MS/MS can be considered as a useful tool for human Apo kinetic studies using stable isotopes.
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Affiliation(s)
- Mikaël Croyal
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Fanta Fall
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Véronique Ferchaud-Roucher
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Maud Chétiveaux
- CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Yassine Zaïr
- CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Khadija Ouguerram
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France
| | - Michel Krempf
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France Department of Endocrinology, Metabolic Diseases, and Nutrition, G and R Laennec Hospital, F-44093 Nantes, France
| | - Estelle Nobécourt
- INRA, UMR 1280, Physiologie des Adaptations Nutritionnelles, CHU Hôtel-Dieu, F-44000 Nantes, France CRNHO, West Human Nutrition Research Center, CHU, F-44093 Nantes, France Department of Endocrinology, Metabolic Diseases, and Nutrition, G and R Laennec Hospital, F-44093 Nantes, France
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Kurt B, Soufi M, Sattler A, Schaefer JR. Lipoprotein(a)-clinical aspects and future challenges. Clin Res Cardiol Suppl 2015; 10:26-32. [PMID: 25732622 PMCID: PMC4361767 DOI: 10.1007/s11789-015-0075-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Lipoprotein(a) (Lp(a)) was first described by K. Berg and is known for more than 50 years. It is an interesting particle and combines the atherogenic properties of low-density lipoprotein (LDL)-cholesterol as well as the thrombogenic properties of plasminogen inactivation. However, due to technical problems and publication of negative trials the potential role of Lp(a) in atherosclerosis was severely underestimated. In recent years our understanding of the function and importance of Lp(a) improved. Interventional trials with niacin failed to demonstrate any benefit of lowering Lp(a); however, several studies confirmed the residual cardiovascular disease (CVD) risk of elevated Lp(a). LDL/Lp(a) apheresis is able to lower Lp(a) and some new drugs under development should help us to lower Lp(a) in the near future. It will be important to follow this with hard endpoint trials. Until then most clinicians recommend the use of an aggressive LDL-lowering approach in patients with high Lp(a). Since most of these patients with high Lp(a) might have manifested atherosclerosis anyway, we would also consider the use of acetylsalicylic acid.
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Affiliation(s)
- Bilgen Kurt
- Internal Medicine, Preventive Cardiology, University Clinic Gießen and Marburg, 35033, Marburg, Germany
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McNeal CJ. Lipoprotein(a): Its relevance to the pediatric population. J Clin Lipidol 2015; 9:S57-66. [PMID: 26343213 DOI: 10.1016/j.jacl.2015.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 06/09/2015] [Accepted: 07/14/2015] [Indexed: 11/26/2022]
Abstract
Lipoprotein(a) (Lp(a)) is a highly atherogenic and heterogeneous lipoprotein that is inherited in an autosomal codominant trait. A unique aspect of this lipoprotein is that it is fully expressed by the first or second year of life in children, a pattern that is distinctly different from other lipoproteins, which typically only reach adult levels after adolescence. Despite decades of research, Lp(a) metabolism is still poorly understood but what is abundantly clear is that it is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). The Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents does not recommend measuring Lp(a) levels as part of routine screening except in youth with an ischemic or hemorrhagic stroke or youth with a parental history of ASCVD not explained by classical risk factors. One of the reasons that both the pediatric and adult guidelines fail to include this lipoprotein as part of routine lipid screening is the absence of data to show that lowering Lp(a) will reduce current or future ASCVD risk independently of low-density lipoprotein cholesterol (LDL-C) lowering. The cholesterol carried by Lp(a) is included in the low-density lipoprotein cholesterol measurement, but a separate test is used to measure the lipoprotein mass and/or cholesterol carried only by Lp(a). Because levels seem to be largely under genetic control, studies of lifestyle modification have been inconclusive although one study in obese children showed a decrease in the Lp(a) level comparable with the favorable effect on other lipids. The most compelling data regarding the importance of Lp(a) in the pediatric population are the increased risk associated with arterial ischemic stroke, a risk that is comparable with that associated with antiphospholipid antibodies or protein C deficiency. Although no specific pharmaceutical treatments are recommended to lower Lp(a) levels in youth, it is vitally important to educate youth and their parents about the excessive risk associated with this lipoprotein and the need to avoid the acquisition of other lifestyle-related risk factors such as smoking, excess weight, and physical inactivity to preserve more ideal cardiovascular health in adulthood.
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Affiliation(s)
- Catherine J McNeal
- Division of Cardiology, Department of Internal Medicine, Baylor Scott & White Health, Temple, TX, USA.
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Croyal M, Ouguerram K, Passard M, Ferchaud-Roucher V, Chétiveaux M, Billon-Crossouard S, de Gouville AC, Lambert G, Krempf M, Nobécourt E. Effects of Extended-Release Nicotinic Acid on Apolipoprotein (a) Kinetics in Hypertriglyceridemic Patients. Arterioscler Thromb Vasc Biol 2015; 35:2042-7. [PMID: 26160958 DOI: 10.1161/atvbaha.115.305835] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/24/2015] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To determine the mechanisms by which extended-release nicotinic acid reduces circulating lipoprotein (a) concentrations in hypertriglyceridemic patients. APPROACH AND RESULTS Eight nondiabetic, obese male subjects (aged 48±12 years; body mass index, 31.2±1.8 kg/m(2)) with hypertriglyceridemia (triglycerides, 226±78 mg/dL) were enrolled in an 8 week, double blind, placebo-controlled cross-over study. At the end of each treatment phase, fasted subjects received a 10 µmol/L per kg bolus injection of [5,5,5-(2)H3]-l-Leucine immediately followed by constant infusion of [5,5,5-(2)H3]-l-Leucine (10 µmol L(-1) kg(-1) h(-1)) for 14 hours, and blood samples were collected. A liquid chromatography-tandem mass spectrometry method was used to study apolipoprotein (a) (Apo(a)) kinetics. The fractional catabolic rate of Apo(a) was calculated with a single compartmental model using the apolipoprotein B100 (ApoB100) containing very low density lipoprotein tracer enrichment as a precursor pool. Extended-release nicotinic acid decreased plasma triglycerides (-46%; P=0.023), raised high-density lipoprotein cholesterol (+20%; P=0.008), and decreased Apo(a) plasma concentrations (-20%; P=0.008). Extended-release nicotinic acid also decreased ApoB100 (22%; P=0.008) and proprotein convertase subtilisin/kexin type 9 (PCSK9, -29%; P=0.008) plasma concentrations. Apo(a) fractional catabolic rate and production rates were decreased by 37% (0.58±0.28 versus 0.36±0.19 pool/d; P=0.008) and 50% (1.4±0.8 versus 0.7±0.4 nmol/kg per day; P=0.008), respectively. CONCLUSIONS Extended-release nicotinic acid treatment decreased Apo(a) plasma concentrations by 20%, production rates by 50%, and catabolism by 37%. ApoB100 and PCSK9 concentrations were also decreased by treatment, but no correlation was found with Apo(a) kinetic parameters.
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Affiliation(s)
- Mikaël Croyal
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Khadija Ouguerram
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Maxime Passard
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Véronique Ferchaud-Roucher
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Maud Chétiveaux
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Stéphanie Billon-Crossouard
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Anne-Charlotte de Gouville
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Gilles Lambert
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
| | - Michel Krempf
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.).
| | - Estelle Nobécourt
- From the CRNH, West Human Nutrition Research Center, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K., E.N.); UMR 1280 PhAN Laboratory, National Institute of Agronomic Research, INRA, CHU Hôtel Dieu, HNB1, Nantes, France (M.C., K.O., M.P., V.F.-R., S.B.-C., G.L., M.K.); University of Nantes and Medical School, Nantes, France (M.C., K.O., M.P., M.C., S.B.-C., G.L., M.K., E.N.); GlaxoSmithKline, Les Ulis, France (A.-C.d.G.); and Endocrinology and Nutrition Department, G and R Laennec Hospital, Bd Jacques Monod, Nantes, France (M.K., E.N.)
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Santos RD, Raal FJ, Catapano AL, Witztum JL, Steinhagen-Thiessen E, Tsimikas S. Mipomersen, an antisense oligonucleotide to apolipoprotein B-100, reduces lipoprotein(a) in various populations with hypercholesterolemia: results of 4 phase III trials. Arterioscler Thromb Vasc Biol 2015; 35:689-99. [PMID: 25614280 DOI: 10.1161/atvbaha.114.304549] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE Lp(a) is an independent, causal, genetic risk factor for cardiovascular disease and aortic stenosis. Current pharmacological lipid-lowering therapies do not optimally lower Lp(a), particularly in patients with familial hypercholesterolemia (FH). APPROACH AND RESULTS In 4 phase III trials, 382 patients on maximally tolerated lipid-lowering therapy were randomized 2:1 to weekly subcutaneous mipomersen 200 mg (n=256) or placebo (n=126) for 26 weeks. Populations included homozygous FH, heterozygous FH with concomitant coronary artery disease (CAD), severe hypercholesterolemia, and hypercholesterolemia at high risk for CAD. Lp(a) was measured 8× between baseline and week 28 inclusive. Of the 382 patients, 57% and 44% had baseline Lp(a) levels >30 and >50 mg/dL, respectively. In the pooled analysis, the mean percent decrease (median, interquartile range in Lp(a) at 28 weeks was significantly greater in the mipomersen group compared with placebo (-26.4 [-42.8, -5.4] versus -0.0 [-10.7, 15.3]; P<0.001). In the mipomersen group in patients with Lp(a) levels >30 or >50 mg/dL, attainment of Lp(a) values ≤30 or ≤50 mg/dL was most frequent in homozygous FH and severe hypercholesterolemia patients. In the combined groups, modest correlations were present between percent change in apolipoprotein B-100 and Lp(a) (r=0.43; P<0.001) and low-density lipoprotein cholesterol and Lp(a) (r=0.36; P<0.001) plasma levels. CONCLUSIONS Mipomersen consistently and effectively reduced Lp(a) levels in patients with a variety of lipid abnormalities and cardiovascular risk. Modest correlations were present between apolipoprotein B-100 and Lp(a) lowering but the mechanistic relevance mediating Lp(a) reduction is currently unknown.
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Affiliation(s)
- Raul D Santos
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.)
| | - Frederick J Raal
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.)
| | - Alberico L Catapano
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.)
| | - Joseph L Witztum
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.)
| | - Elisabeth Steinhagen-Thiessen
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.)
| | - Sotirios Tsimikas
- From the Lipid Clinic Heart Institute (InCor), University of São Paulo Medical School Hospital, São Paulo, Brazil (R.D.S.); Carbohydrate and Lipid Metabolism Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa (F.J.R.); Department of Pharmacological and Biomolecular Sciences, University of Milan, IRCCS Multimedica, Milan, Italy (A.L.C.); Lipid Ambulatory Clinic, Charite-Universitaetsmedizin Berlin, Berlin, Germany (E.S.-T.); and University of California San Diego, La Jolla (J.L.W., S.T.).
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Enkhmaa B, Anuurad E, Zhang W, Berglund L. Significant associations between lipoprotein(a) and corrected apolipoprotein B-100 levels in African-Americans. Atherosclerosis 2014; 235:223-9. [PMID: 24859635 PMCID: PMC4095745 DOI: 10.1016/j.atherosclerosis.2014.04.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 04/26/2014] [Accepted: 04/28/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Lipoprotein(a), Lp(a), represents an apolipoprotein (apo) B-carrying lipoprotein, yet the relationship between Lp(a) and apoB levels has not been fully explored. METHODS We addressed the relationship between Lp(a) and apoB-containing lipoprotein levels in 336 Caucasians and 224 African-Americans. Our approach takes unique molecular properties of Lp(a) as well as contribution of Lp(a) to the levels of these lipoproteins into account. RESULTS Levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), apoB and apoB/apoA-1 did not differ across ethnicity. African-Americans had higher levels of Lp(a) and high-density lipoprotein cholesterol and lower triglyceride levels compared to Caucasians. Lp(a) levels were correlated with levels of TC (p < 0.005), LDL-C (p < 0.001), apoB (p < 0.05) or apoB/apoA-1 (p < 0.05) in both ethnic groups. These associations remained significant only in African-Americans after adjustments for the contribution of Lp(a)-cholesterol or Lp(a)-apoB. Furthermore, taking Lp(a)-apoB into account, allele-specific apo(a) levels were significantly associated with apoB levels and the apoB/apoA-1 ratio in African-Americans. The latter associations in African-Americans remained significant for allele-specific apo(a) levels for smaller apo(a) sizes (<26 K4 repeats), after controlling for the effects of age, sex, and BMI. CONCLUSIONS Although TC, LDL-C, and apoB levels were comparable between African-Americans and Caucasians, the associations of these parameters with Lp(a) and allele specific apo(a) levels differed between these two ethnic groups. In African-Americans, apoB and apoB/apoA-1 remained consistently and positively associated with both Lp(a) and allele-specific apo(a) levels after adjustments for the contribution of Lp(a)-apoB. The findings suggest an interethnic difference with a closer relationship between Lp(a) and apoB among African-Americans.
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Affiliation(s)
- Byambaa Enkhmaa
- Department of Internal Medicine, University of California, Davis, CA, USA
| | - Erdembileg Anuurad
- Department of Internal Medicine, University of California, Davis, CA, USA
| | - Wei Zhang
- Department of Internal Medicine, University of California, Davis, CA, USA
| | - Lars Berglund
- Department of Internal Medicine, University of California, Davis, CA, USA; Department of Veterans Affairs, Northern California Health Care System, Sacramento, CA, USA.
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Abstract
PURPOSE OF REVIEW Lipoprotein(a) [Lp(a)] is an atherogenic lipoprotein. The metabolism of this lipoprotein is still not well understood. RECENT FINDINGS It has long been known that the plasma concentration of Lp(a) is highly heritable, with its genetic determinants located in the apo(a) locus and regulating the rate of hepatic apo(a) production. Recent human intervention trials have convincingly established that, in addition to apo(a) production, hepatic apoB100 production plays an important role in Lp(a) levels. Although the major site and mode of Lp(a) clearance remain unidentified, a recent cell and animal study points to the involvement of the hepatic scavenger receptor class B type I in the uptake of both the lipid and protein constituents of Lp(a) from plasma. SUMMARY Progress in the understanding of Lp(a) metabolism has the potential to lead to the development of novel and specific treatments for the reduction of Lp(a) levels and the associated risk of cardiovascular disease.
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Affiliation(s)
- Stefania Lamon-Fava
- aCardiovascular Nutrition Laboratory, Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University bGerald J. and Dorothy R. Friedman School of Nutrition Science and Policy, Tufts University, Boston, Massachusetts, USA cNorthwest Lipid Metabolism and Diabetes Research Laboratories, University of Washington, Seattle, Washington, USA
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Lassman ME, McLaughlin TM, Zhou H, Pan Y, Marcovina SM, Laterza O, Roddy TP. Simultaneous quantitation and size characterization of apolipoprotein(a) by ultra-performance liquid chromatography/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:1101-1106. [PMID: 24711273 DOI: 10.1002/rcm.6883] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Apolipoprotein(a) is a polymorphic glycoprotein covalently bound to apoB100 in Lp(a) particles and has been described to be both atherogenic and prothrombotic, although its exact mechanism of action is not well defined. Apolipoprotein(a) is routinely measured by immunoassays. Unfortunately, the accuracy of the measurement can be affected by the apolipoprotein(a) size (number of kringles) polymorphism in Lp(a) particles. Here we describe an ultra-performance liquid chromatography/mass spectrometry (UPLC/MS) assay that is capable of measuring apolipoprotein(a) concentrations while simultaneously determining the number of kringles present per protein. METHODS Plasma samples were diluted and proteins de-lipidated with deoxycholate prior to tryptic digestion. Distinct tryptic peptides from different regions of apolipoprotein(a) were measured to determine both concentration and the number of kringles present per protein. Separation and quantitation of tryptic peptides is carried out at 700 μL/min using a 1.7 µm C18 column (2.1 × 100 mm) coupled to a Thermo Vantage triple quadrupole (QQQ) mass spectrometer with a heated electrospray ionization (HESI) source. RESULTS This method was compared to established methods for measuring concentration (monoclonal antibody based ELISA) and size (gel-electrophoresis) using 80 plasma samples proved by NWLRL. The slope and r(2) value for the correlation of concentrations were determined to be 0.96 and 0.98, demonstrating excellent agreement of absolute values between the UPLC/MS and ELISA methods. As measured by UPLC/MS, the average kringle number or size is smaller than determined by the electrophoretic method. CONCLUSIONS A single UPLC/MS method was developed capable of measuring apolipoprotein(a) concentration and size (by measuring the number of kringles per protein). This assay passes criteria required for 'fit for purpose' assays including sensitivity, intra and interday reproducibility and freeze/thaw stability. While the agreement between UPLC/MS and ELISA is excellent for concentration and may provide researchers with additional tools for studying apolipoprotein(a), the dissimilarities between UPLC/MS and the electrophoretic method may also be exploited for understanding apolipoprotein(a) structure and function.
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Affiliation(s)
- Michael E Lassman
- Merck Research Laboratories, 126 E. Lincoln Ave., Rahway, NJ, 07065, USA
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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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Boffa MB, Koschinsky ML. Update on lipoprotein(a) as a cardiovascular risk factor and mediator. Curr Atheroscler Rep 2014; 15:360. [PMID: 23990263 DOI: 10.1007/s11883-013-0360-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Recent genetic studies have put the spotlight back onto lipoprotein(a) [Lp(a)] as a causal risk factor for coronary heart disease. However, there remain significant gaps in our knowledge with respect to how the Lp(a) particle is assembled, the route of its catabolism, and the mechanism(s) of Lp(a) pathogenicity. It has long been speculated that the effects of Lp(a) in the vasculature can be attributed to both its low-density lipoprotein moiety and the unique apolipoprotein(a) component, which is strikingly similar to the kringle-containing fibrinolytic zymogen plasminogen. However, the ability of Lp(a) to modulate either purely thrombotic or purely atherothrombotic processes in vivo remains unclear. The presence of oxidized phospholipid on Lp(a) may underlie many of the proatherosclerotic effects of Lp(a) that have been identified both in cell models and in animal models, and provides a possible avenue for identifying therapeutics aimed at mitigating the effects of Lp(a) in the vasculature. However, the beneficial effects of targeted Lp(a) therapeutics, designed to either lower Lp(a) concentrations or interfere with its effects, on cardiovascular outcomes remains to be determined.
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Affiliation(s)
- Michael B Boffa
- Department of Chemistry & Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor, ON, Canada.
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In vivo kinetic studies to further understand pathogenesis of abnormal lipoprotein metabolism in chronic kidney disease. Clin Exp Nephrol 2013; 18:261-4. [PMID: 24129559 DOI: 10.1007/s10157-013-0881-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 09/25/2013] [Indexed: 10/26/2022]
Abstract
Patients undergoing hemodialysis (HD) have been shown to be at increased risk for cardiovascular disease (CVD) morbidity and mortality which are, at least in part, due to uremic dyslipidemia including increased triglyceride-rich lipoproteins, in particular remnants, decreased high-density lipoprotein (HDL), and increased lipoprotein(a) [Lp(a)]. In vivo kinetic studies using stable isotope revealed that apolipoprotein (apo)A-I, a primary apoprotein constitute of HDL, was catabolized at a faster rate in HD patients, leading to decreased apoA-I, and therefore reduced HDL cholesterol concentrations. Likewise, apoB catabolic rates were significantly lower in intermediate-density lipoprotein (IDL) and low-density lipoprotein (LDL) apoB; the latter is also accompanied by a decreased production rate. In HD patients, IDL apoB levels were elevated, but LDL apoB levels remained within the normal range. Nonetheless, a prolonged residence time for LDL apoB of 2-5 days, made LDL more atherogenic. Atorvastatin completely ameliorated impaired LDL apoB catabolism. With regard to Lp(a) metabolism, both apoB and apo(a) were found to be slowly catabolized, indicating roles of normal kidney function on Lp(a) catabolism. Finally, a compartmental model suggests intracellular, rather than extracellular, assembly of Lp(a). This in vivo kinetic evidence will uncover the underlying mechanism for uremic dyslipidemia and provide strategies to reduce CVD in HD patients.
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