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Liu E, Karpf L, Bohl D. Neuroinflammation in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia and the Interest of Induced Pluripotent Stem Cells to Study Immune Cells Interactions With Neurons. Front Mol Neurosci 2022; 14:767041. [PMID: 34970118 PMCID: PMC8712677 DOI: 10.3389/fnmol.2021.767041] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
Inflammation is a shared hallmark between amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). For long, studies were conducted on tissues of post-mortem patients and neuroinflammation was thought to be only bystander result of the disease with the immune system reacting to dying neurons. In the last two decades, thanks to improving technologies, the identification of causal genes and the development of new tools and models, the involvement of inflammation has emerged as a potential driver of the diseases and evolved as a new area of intense research. In this review, we present the current knowledge about neuroinflammation in ALS, ALS-FTD, and FTD patients and animal models and we discuss reasons of failures linked to therapeutic trials with immunomodulator drugs. Then we present the induced pluripotent stem cell (iPSC) technology and its interest as a new tool to have a better immunopathological comprehension of both diseases in a human context. The iPSC technology giving the unique opportunity to study cells across differentiation and maturation times, brings the hope to shed light on the different mechanisms linking neurodegeneration and activation of the immune system. Protocols available to differentiate iPSC into different immune cell types are presented. Finally, we discuss the interest in studying monocultures of iPS-derived immune cells, co-cultures with neurons and 3D cultures with different cell types, as more integrated cellular approaches. The hope is that the future work with human iPS-derived cells helps not only to identify disease-specific defects in the different cell types but also to decipher the synergistic effects between neurons and immune cells. These new cellular tools could help to find new therapeutic approaches for all patients with ALS, ALS-FTD, and FTD.
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Affiliation(s)
- Elise Liu
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, INSERM, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Léa Karpf
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, INSERM, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
| | - Delphine Bohl
- Sorbonne Université, Institut du Cerveau - Paris Brain Institute - ICM, INSERM, CNRS, AP-HP, Hôpital de la Pitié-Salpêtrière, Paris, France
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Chapman MJ, Orsoni A, Tan R, Mellett NA, Nguyen A, Robillard P, Giral P, Thérond P, Meikle PJ. LDL subclass lipidomics in atherogenic dyslipidemia: effect of statin therapy on bioactive lipids and dense LDL. J Lipid Res 2020; 61:911-932. [PMID: 32295829 PMCID: PMC7269759 DOI: 10.1194/jlr.p119000543] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 04/01/2020] [Indexed: 01/05/2023] Open
Abstract
Atherogenic LDL particles are physicochemically and metabolically heterogeneous. Can bioactive lipid cargo differentiate LDL subclasses, and thus potential atherogenicity? What is the effect of statin treatment? Obese hypertriglyceridemic hypercholesterolemic males [n = 12; lipoprotein (a) <10 mg/dl] received pitavastatin calcium (4 mg/day) for 180 days in a single-phase unblinded study. The lipidomic profiles (23 lipid classes) of five LDL subclasses fractionated from baseline and post-statin plasmas were determined by LC-MS. At baseline and on statin treatment, very small dense LDL (LDL5) was preferentially enriched (up to 3-fold) in specific lysophospholipids {LPC, lysophosphatidylinositol (LPI), lysoalkylphosphatidylcholine [LPC(O)]; 9, 0.2, and 0.14 mol per mole of apoB, respectively; all P < 0.001 vs. LDL1-4}, suggesting elevated inflammatory potential per particle. In contrast, lysophosphatidylethanolamine was uniformly distributed among LDL subclasses. Statin treatment markedly reduced absolute plasma concentrations of all LDL subclasses (up to 33.5%), including LPC, LPI, and LPC(O) contents (up to -52%), consistent with reduction in cardiovascular risk. Despite such reductions, lipotoxic ceramide load per particle in LDL1-5 (1.5-3 mol per mole of apoB; 3-7 mmol per mole of PC) was either conserved or elevated. Bioactive lipids may constitute biomarkers for the cardiometabolic risk associated with specific LDL subclasses in atherogenic dyslipidemia at baseline, and with residual risk on statin therapy.
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Affiliation(s)
- M John Chapman
- Endocrinology Metabolism Division, Pitié-Salpetrière University Hospital, Sorbonne University and National Institute for Health and Medical Research (INSERM), Paris, France; Metabolomics Laboratory Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia. mailto:
| | - Alexina Orsoni
- Service de Biochimie AP-HP, HU Paris-Saclay, Bicetre University Hospital, Le Kremlin Bicêtre and EA 7357, Paris-Saclay University, Chatenay-Malabry, France
| | - Ricardo Tan
- Metabolomics Laboratory Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Natalie A Mellett
- Metabolomics Laboratory Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Anh Nguyen
- Metabolomics Laboratory Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
| | - Paul Robillard
- Endocrinology Metabolism Division, Pitié-Salpetrière University Hospital, Sorbonne University and National Institute for Health and Medical Research (INSERM), Paris, France
| | - Philippe Giral
- INSERM UMR1166 and Cardiovascular Prevention Units, ICAN-Institute of CardioMetabolism and Nutrition, AP-HP, Pitié-Salpetrière University Hospital, Paris, France
| | - Patrice Thérond
- Service de Biochimie AP-HP, HU Paris-Saclay, Bicetre University Hospital, Le Kremlin Bicêtre and EA 7357, Paris-Saclay University, Chatenay-Malabry, France
| | - Peter J Meikle
- Metabolomics Laboratory Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia
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Phan K, He Y, Pickford R, Bhatia S, Katzeff JS, Hodges JR, Piguet O, Halliday GM, Kim WS. Uncovering pathophysiological changes in frontotemporal dementia using serum lipids. Sci Rep 2020; 10:3640. [PMID: 32107421 PMCID: PMC7046653 DOI: 10.1038/s41598-020-60457-w] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 02/10/2020] [Indexed: 12/12/2022] Open
Abstract
Blood serum is enriched in lipids and has provided a platform to understand the pathogenesis of a number of human diseases with improved diagnosis and development of biomarkers. Understanding lipid changes in neurodegenerative diseases is particularly important because of the fact that lipids make up >50% of brain tissues. Frontotemporal dementia (FTD) is a common cause of early onset dementia, characterized by brain atrophy in the frontal and temporal regions, concomitant loss of lipids and dyslipidemia. However, little is known about the link between dyslipidemia and FTD pathophysiology. Here, we utilized an innovative approach – lipidomics based on mass spectrometry – to investigate three key aspects of FTD pathophysiology – mitochondrial dysfunction, inflammation, and oxidative stress. We analyzed the lipids that are intrinsically linked to neurodegeneration in serum collected from FTD patients and controls. We found that cardiolipin, acylcarnitine, lysophosphatidylcholine, platelet-activating factor, o-acyl-ω-hydroxy fatty acid and acrolein were specifically altered in FTD with strong correlation between the lipids, signifying pathophysiological changes in FTD. The lipid changes were verified by measurement of the common disease markers (e.g. ATP, cytokine, calcium) using conventional assays. When put together, these results support the use of lipidomics technology to detect pathophysiological changes in FTD.
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Affiliation(s)
- Katherine Phan
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia
| | - Ying He
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia
| | - Russell Pickford
- Bioanalytical Mass Spectrometry Facility, University of New South Wales, Sydney, NSW, Australia
| | - Surabhi Bhatia
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia
| | - Jared S Katzeff
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia
| | - John R Hodges
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia.,ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia
| | - Olivier Piguet
- ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia.,The University of Sydney, Brain and Mind Centre & School of Psychology, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Glenda M Halliday
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia. .,ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia. .,The University of Sydney, Brain and Mind Centre & School of Psychology, Sydney, NSW, Australia. .,Neuroscience Research Australia, Sydney, NSW, Australia. .,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
| | - Woojin Scott Kim
- The University of Sydney, Brain and Mind Centre & Central Clinical School, Sydney, NSW, Australia. .,Neuroscience Research Australia, Sydney, NSW, Australia. .,School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
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Fratta Pasini A, Stranieri C, Pasini A, Vallerio P, Mozzini C, Solani E, Cominacini M, Cominacini L, Garbin U. Lysophosphatidylcholine and carotid intima-media thickness in young smokers: a role for oxidized LDL-induced expression of PBMC lipoprotein-associated phospholipase A2? PLoS One 2013; 8:e83092. [PMID: 24358251 PMCID: PMC3866188 DOI: 10.1371/journal.pone.0083092] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Accepted: 11/08/2013] [Indexed: 12/13/2022] Open
Abstract
Background Although cigarette smoking has been associated with carotid intima-media thickness (CIMT) the mechanisms are yet not completely known. Lysophosphatidylcholine (lysoPC), a main product of lipoprotein-associated phospholipase A2 (Lp-PLA2) activity, appears to be a major determinant of the pro-atherogenic properties of oxidized LDL (oxLDL) and to induce proteoglycan synthesis, a main player in intimal thickening. In this study we assessed whether cigarette smoking-induced oxidative stress may influence plasma Lp-PLA2 and lysoPC and Lp-PLA2 expression in peripheral blood mononuclear cells (PBMC), as well as the relationship between lysoPC and CIMT. Methods/Results 45 healthy smokers and 45 age and sex-matched subjects participated in this study. Smokers, compared to non-smokers, showed increased plasma concentrations of oxLDL, Lp-PLA2 and lysoPC together with up-regulation of Lp-PLA2 (mRNA and protein) expression in PBMC (P<0.001). Plasma Lp-PLA2 positively correlated with both lysoPC (r=0.639, P<0.001) and PBMC mRNA Lp-PLA2 (r=0.484, P<0.001) in all subjects. Moreover CIMT that was higher in smokers (P<0.001), positively correlated with lysoPC (r=0.55, P<0.001). Then in invitro study we demonstrated that both oxLDL (at concentrations similar to those found in smoker’s serum) and oxidized phospholipids contained in oxLDL, were able to up-regulate mRNA Lp-PLA2 in PBMC. This effect was likely due, at least in part, to the enrichment in oxidized phospholipids found in PBMC after exposure to oxLDL. Our results also showed that in human aortic smooth muscle cells lysoPC, at concentrations similar to those found in smokers, increased the expression of biglycan and versican, two main proteoglycans. Conclusions In smokers a further effect of raised oxidative stress is the up-regulation of Lp-PLA2 expression in PBMC with subsequent increase of plasma Lp-PLA2 and lysoPC. Moreover the correlation between lysoPC and CIMT together with the finding that lysoPC up-regulates proteoglycan synthesis suggests that lysoPC may be a link between smoking and intimal thickening.
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Affiliation(s)
- Anna Fratta Pasini
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
- * E-mail:
| | - Chiara Stranieri
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Andrea Pasini
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Paola Vallerio
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Chiara Mozzini
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Erika Solani
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Mattia Cominacini
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Luciano Cominacini
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
| | - Ulisse Garbin
- Section of Internal Medicine D, Department of Medicine, University of Verona, Verona, Italy
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Tanaka T, Ikeda K, Yamamoto Y, Iida H, Kikuchi H, Morita T, Yamasoba T, Nagai R, Nakajima T. Effects of Serum Amyloid A and Lysophosphatidylcholine on Intracellular Calcium Concentration in Human Coronary Artery Smooth Muscle Cells. Int Heart J 2011; 52:185-93. [DOI: 10.1536/ihj.52.185] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Tomofumi Tanaka
- Department of Cardiovascular Medicine, The University of Tokyo
| | - Kenichi Ikeda
- Department of Cardiovascular Medicine, The University of Tokyo
| | - Yumiko Yamamoto
- Department of Cardiovascular Medicine, The University of Tokyo
| | - Haruko Iida
- Department of Ischemic Circulatory Physiology, The University of Tokyo
| | | | - Toshihiro Morita
- Department of Ischemic Circulatory Physiology, The University of Tokyo
| | | | - Ryozo Nagai
- Department of Cardiovascular Medicine, The University of Tokyo
| | - Toshiaki Nakajima
- Department of Ischemic Circulatory Physiology, The University of Tokyo
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Rosenson RS, Elliott M, Stasiv Y, Hislop C. Randomized trial of an inhibitor of secretory phospholipase A2 on atherogenic lipoprotein subclasses in statin-treated patients with coronary heart disease. Eur Heart J 2010; 32:999-1005. [PMID: 21081550 DOI: 10.1093/eurheartj/ehq374] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
AIMS To investigate the effects of secretory phospholipase A2 (sPLA(2)) inhibition on plasma lipoproteins. Secretory phospholipase A2 isoenzymes promote atherosclerosis by mechanisms that include lipoprotein modification, retention, and oxidation. METHODS AND RESULTS Phospholipase Levels And Serological Markers of Atherosclerosis II (PLASMA II) is a Phase II, randomized, double-blind, placebo-controlled parallel-arm study of two once-daily doses of the novel sPLA(2) inhibitor, 1-H-indole-3-glyoxamide or varespladib methyl (Anthera Pharmaceuticals, Hayward, CA, USA). One hundred and thirty-five stable coronary heart disease patients were treated with either varespladib methyl 250 mg once daily, varespladib methyl 500 mg once daily, or placebo for 8 weeks. Varespladib methyl treatment resulted in statistically significant dose-dependent reductions that were different from placebo in sPLA(2) concentration, low-density lipoprotein (LDL) cholesterol, and non-high-density lipoprotein (HDL) cholesterol. When compared with placebo, varespladib methyl 500 mg once daily reduced LDL cholesterol by 15% (P < 0.001), non-HDL cholesterol by 15% (P < 0.001), total very LDL (VLDL) particle concentration by 14% (P = 0.022), and small VLDL particle concentration by 24% (P = 0.030). Relative to baseline, varespladib methyl 500 mg once daily reduced total LDL particle concentration (7%, P = 0.002) and small LDL particle concentration (11%, P = 0.014). CONCLUSION Reductions in atherogenic lipoproteins suggest that varespladib methyl 500 mg once daily may be an effective anti-atherosclerotic agent. Trial registered at ClinicalTrials.gov, identifier: NCT00525954.
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Affiliation(s)
- Robert S Rosenson
- Mount Sinai Heart-Box 1030, Mount Sinai School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA.
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Association of carotid plaque Lp-PLA(2) with macrophages and Chlamydia pneumoniae infection among patients at risk for stroke. PLoS One 2010; 5:e11026. [PMID: 20543948 PMCID: PMC2882946 DOI: 10.1371/journal.pone.0011026] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2010] [Accepted: 05/11/2010] [Indexed: 11/20/2022] Open
Abstract
Background We previously showed that the burden of Chlamydia pneumoniae in carotid plaques was significantly associated with plaque interleukin (IL)-6, and serum IL-6 and C-reactive protein (CRP), suggesting that infected plaques contribute to systemic inflammatory markers in patients with stroke risk. Since lipoprotein-associated phospholipase A2 (Lp-PLA2) mediates inflammation in atherosclerosis, we hypothesized that serum Lp-PLA2 mass and activity levels and plaque Lp-PLA2 may be influenced by plaque C. pneumoniae infection. Methodology/Principal Findings Forty-two patients underwent elective carotid endarterectomy. Tissue obtained at surgery was stained by immunohistochemistry for Lp-PLA2 grade, macrophages, IL-6, C. pneumoniae and CD4+ and CD8+ cells. Serum Lp-PLA2 activity and mass were measured using the colorimetric activity method (CAM™) and ELISA, respectively. Serum homocysteine levels were measured by HPLC. Eleven (26.2%) patients were symptomatic with transient ischemic attacks. There was no correlation between patient risk factors (smoking, coronary artery disease, elevated cholesterol, diabetes, obesity, hypertension and family history of genetic disorders) for atherosclerosis and serum levels or plaque grade for Lp-PLA2. Plaque Lp-PLA2 correlated with serum homocysteine levels (p = 0.013), plaque macrophages (p<0.01), and plaque C. pneumoniae (p<0.001), which predominantly infected macrophages, co-localizing with Lp-PLA2. Conclusions The significant association of plaque Lp-PLA2 with plaque macrophages and C. pneumoniae suggests an interactive role in accelerating inflammation in atherosclerosis. A possible mechanism for C. pneumoniae in the atherogenic process may involve infection of macrophages that induce Lp-PLA2 production leading to upregulation of inflammatory mediators in plaque tissue. Additional in vitro and in vivo research will be needed to advance our understanding of specific C. pneumoniae and Lp-PLA2 interactions in atherosclerosis.
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Derbali H, Bossé Y, Côté N, Pibarot P, Audet A, Pépin A, Arsenault B, Couture C, Després JP, Mathieu P. Increased biglycan in aortic valve stenosis leads to the overexpression of phospholipid transfer protein via Toll-like receptor 2. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:2638-45. [PMID: 20382708 DOI: 10.2353/ajpath.2010.090541] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Aortic stenosis (AS) is the most common valvular heart disease, and it is suspected that atherosclerotic mechanisms are involved in the development of this disorder. Therefore, the retention of lipids within the aortic valve may play a role in the pathobiology of AS. In this study, a gene expression microarray experiment was conducted on human aortic valves with and without AS. The expression levels of transcripts encoding proteoglycans and enzymes involved in lipid retention were compared between the two groups. The microarray results were subsequently replicated in a cohort of 87 AS valves and 36 control valves. In addition, the interaction between proteoglycan and lipid-modifying enzyme was documented in isolated valve interstitial cells (VICs). The microarray results indicated that only biglycan (BGN) and phospholipid transfer protein (PLTP) were overexpressed in the AS valves. These results were then confirmed by quantitative PCR. The immunohistochemical analysis revealed a colocalization of BGN, PLTP, and Toll-like receptor-2 (TLR 2) in AS valves. In vitro, we showed that BGN induces the production of PLTP in VICs via the stimulation of TLR 2. Thus, increased accumulation of BGN in AS valves contributes to the production of PLTP via TLR 2. These results suggest that intricate links between valve matrix proteins, inflammation, and lipid retention are involved in the pathobiology of AS.
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Affiliation(s)
- Habib Derbali
- Laboratoire d'Etudes Moléculaires des Valvulopathies, Groupe de Recherche en Valvulopathies, Institut Universitaire de Cardiologie et de Pneumologie de Québec, 2725 Chemin Ste-Foy Québec, Quebec, Canada, G1V-4G5
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Abstract
IMPORTANCE OF THE FIELD Atherosclerosis is an inflammatory-immune mediated disease process. Plaque rupture is responsible for the clinical events of ischemic death, myocardial infarction, acute coronary syndromes and ischemic strokes. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) seems to play a major role in the development of such high-risk lesions, in both the coronary and carotid arteries. Darapladib is a selective inhibitor of Lp-PLA(2). AREAS COVERED IN THIS REVIEW An overview of darapladib by reviewing the studies (1990 - 2009) that have provided the rationale for the development of darapladib; and a discussion of its potential merit as a new therapeutic drug to target high-risk atherosclerosis. WHAT THE READER WILL GAIN The reader should gain an understanding of the importance of inflammation during atherogenesis as well as of the biology of Lp-PLA(2) and its proatherogenic role. Additional insights will be gained into the role of selective inhibitors of Lp-PLA(2) as new therapeutic agents. TAKE HOME MESSAGE Darapladib is a selective inhibitor of Lp-PLA(2) and represents a new class of therapeutic agents that target inflammation to treat high-risk atherosclerosis.
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Affiliation(s)
- Quang T Bui
- University of Pennsylvania, Hospital of the University of Pennsylvania, Cardiovascular Institute, Cardiovascular Division, Philadelphia, PA 19104, USA
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Hyaluronan reversed proteoglycan synthesis inhibited by mechanical stress: possible involvement of antioxidant effect. Inflamm Res 2009; 59:471-7. [PMID: 20013025 DOI: 10.1007/s00011-009-0147-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 11/02/2009] [Accepted: 11/25/2009] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Abnormal mechanical stress loaded on the cartilage leads to the osteoarthritis (OA). Although intraarticular hyaluronan (HA) injection is an effective treatment for OA, the underlying mechanism has not been made clear. METHODS Mechanical compression was loaded on the bovine cartilage using the Biopress system. Proteoglycan (PG) and reactive oxygen species (ROS) synthesis were measured with [(35)S] incorporation and fluorescent dye, respectively. Accumulation of peroxynitrite was determined with western blotting using nitrotyrosine antibody. RESULTS Mechanical compression inhibited PG synthesis and enhanced ROS. Externally added HA reversed stress-inhibited PG synthesis and attenuated ROS synthesis. HA also significantly decreased the generation of nitrotyrosine. CONCLUSIONS HA neutralized stress-enhanced ROS synthesis and resulted in the reversing of PG synthesis. These data suggest that HA plays an anabolic effect as an antioxidant.
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Oörni K, Kovanen PT. Lipoprotein modification by secretory phospholipase A(2) enzymes contributes to the initiation and progression of atherosclerosis. Curr Opin Lipidol 2009; 20:421-7. [PMID: 19593123 DOI: 10.1097/mol.0b013e32832fa14d] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE OF REVIEW Secretory phospholipase A2s (sPLA2s) are considered to be important enzymes in the initiation and progression of atherosclerosis. In this review, we discuss the various mechanisms by which the direct action of the sPLA2s on LDL particles in the arterial intima may contribute to atherogenesis. RECENT FINDINGS A wealth of evidence, both in vitro and in vivo, supports a role for the sPLA2s in atherogenesis. Very recently, systemic inhibition of sPLA2s was found to reduce measures of arterial inflammation. The mechanisms behind this inhibition, however, are largely unknown. Here, we discuss the consequences of sPLA2 action on LDL in the arterial intima and address the recent findings regarding the effects of the lipolytic products of sPLA2, lysophosphatidylcholine, and fatty acids on intimal cells. LDL modified by sPLA2 can accumulate in the arterial intima both extracellularly and intracellularly. Importantly, the lipolytic products promote atherosclerosis by monocyte/macrophage recruitment, by enhancing the production of proretentive molecules by vascular smooth muscle cells, and by inducing cell death. SUMMARY Recent findings on sPLA2s support the idea that the enzymes contribute to human atherogenesis not only as initiating agents but also in maintaining plaque inflammation.
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Yang SNY, Osman N, Burch ML, Little PJ. Factors affecting proteoglycan synthesis and structure that modify the interaction with lipoproteins. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/clp.09.37] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Future Role for Selective Phospholipase A2 Inhibitors in the Prevention of Atherosclerotic Cardiovascular Disease. Cardiovasc Drugs Ther 2009; 23:93-101. [DOI: 10.1007/s10557-008-6148-1] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 10/07/2008] [Indexed: 12/21/2022]
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Pettersson C, Fogelstrand L, Rosengren B, Ståhlman S, Hurt-Camejo E, Fagerberg B, Wiklund O. Increased lipolysis by secretory phospholipase A(2) group V of lipoproteins in diabetic dyslipidaemia. J Intern Med 2008; 264:155-65. [PMID: 18298481 DOI: 10.1111/j.1365-2796.2008.01932.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Lipolysis of lipoproteins by secretory phospholipase A(2) group V (sPLA(2)-V) promotes inflammation, lipoprotein aggregation and foam cell formation--all considered as atherogenic mechanisms. OBJECTIVE In this study, we compared the susceptibility to sPLA(2)-V lipolysis of VLDL and LDL from individuals with type 2 diabetes and the metabolic syndrome (T2D-MetS) and from healthy controls. Design. VLDL and LDL were isolated from 38 T2D-MetS subjects and 38 controls, treated pair-wise. Extent of sPLA(2)-V lipolysis was measured as release of nonesterified free fatty acids (NEFA). In a subset of the subjects, lipoprotein composition was determined as a relationship between lipid and apolipoprotein components. RESULTS Mean paired increase in sPLA(2)-V lipolysis after 1 h for T2D-MetS versus control was 2.0 micromol NEFA l(-1) for VLDL (P = 0.004) and 0.75 micromol NEFA l(-1) for LDL (P = 0.001). There were also substantial differences in lipoprotein composition between the groups. T2D-MetS VLDL had higher triglyceride and cholesterol contents than control VLDL. T2D-MetS LDL was smaller and contained more triglycerides and less cholesterol than control LDL. Both VLDL and LDL from T2D-MetS subjects also contained more apolipoprotein CIII per particle. CONCLUSION VLDL and LDL from T2D-MetS individuals were more susceptible to sPLA(2)-V lipolysis than those from control individuals. This may result in elevated levels of NEFA and lysophosphatidylcholine, both in circulation and in LDL, possibly contributing to the elevated inflammatory state and increased risk of cardiovascular diseases seen in these individuals.
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Affiliation(s)
- C Pettersson
- Department of Molecular and Clinical Medicine, The Wallenberg Laboratory, Sahlgrenska Academy University of Gothenburg, Gothenburg, Sweden.
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15
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Abstract
Biglycan, a member of the small leucine rich proteoglycan family, is known to be expressed in almost every tissue of our body. Although there are increasing amount of data on the biological role of biglycan, its cardiac function is still not totally clarified. Cardiac protein profiling of biglycan transgenic mice and other studies revealed its involvement in heart failure, myocardial remodeling, and a possible role in promoting cardioprotection. The localization of biglycan on the cell surface and its "pericellular" arrangement as well as the presence of reactive GAG chains on its surface suggest an involvement in transmission of extracellular signals to intracellular signaling molecules and a role in regulation of Ca(++) trafficking. In this review, the role of biglycan in the heart under normal physiological as well as pathological conditions is summarized and critically discussed.
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Affiliation(s)
- Erika Bereczki
- Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, Szeged, Hungary
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Bereczki E, Gonda S, Csont T, Korpos E, Zvara A, Ferdinandy P, Santha M. Overexpression of biglycan in the heart of transgenic mice: an antibody microarray study. J Proteome Res 2007; 6:854-61. [PMID: 17269742 DOI: 10.1021/pr060571b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Biglycan, a small leucine rich proteoglycan, is expressed in almost every tissue of the body, mainly in the extracellular matrix of connective tissues. Although there is an increasing amount of data on the biological role of biglycan protein, its function is still poorly understood. We aimed to gather more information about the biological function of biglycan protein in the cardiac tissues, and its role in signal transduction. Therefore, we generated transgenic mice overexpressing the human biglycan protein and analyzed the cardiac protein profile of transgenic offsprings using quantitative real-time (QRT)-PCR and proteomics. QRT-PCR results showed that most members of extracellular matrix were downregulated whereas cadherins, TGF-beta1, and TGF-beta2 were upregulated. Antibody microarrayer experiment revealed that pyk2, RAF-1, Mcl-1, syntrophin, calmodulin, isoforms of NOS protein family (eNOS, nNOS, and iNOS), and synaptotagmin proteins were unambiguously upregulated in the heart of biglycan transgenic mice. In this study we show that biglycan directly or indirectly activates proteins involved in cardiac remodeling (TGF-beta, pyk2), signal transduction (RAF-1, Mcl-1, syntrophin, calmodulin, nNOS p38MAPK and MAP kinases), cardioprotection (NOS family, TGF-beta) and Ca++ signaling (connexin, calmodulin, synaptotagmin). On the basis of the results presented here, we conclude that biglycan is a multifunctional extracellular protein that has a pivotal role in pathological remodeling of cardiac tissue and mediates cardioprotection.
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Affiliation(s)
- Erika Bereczki
- Institute of Biochemistry, Biological Research Center of the Hungarian Academy of Sciences, H-6701 Szeged, Hungary
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17
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Le Brazidec H. Lipoproteins and protection of the arterial wall against infection: the "response to the threat of infection" hypothesis. Atherosclerosis 2007; 195:e21-31. [PMID: 17331516 DOI: 10.1016/j.atherosclerosis.2007.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2006] [Revised: 01/18/2007] [Accepted: 01/18/2007] [Indexed: 10/23/2022]
Abstract
The exact reason why lipoproteins are found in the arterial intima is not understood. On the basis of recent findings presented in the literature, we are proposing a hypothesis that the accumulation of lipoprotein in the arterial intima is originally a physiological process, part of our defences against infection designed to protect susceptible segments of the arterial wall from microbial invasion. In addition to the intrinsic antimicrobial activities of the deposited lipids, the formation of fibrin-based matrices within the intima is promoted, fibrinolysis is inhibited, the lipid content exerts a vasoconstrictive influence and smooth muscle cells are mobilised into the intima, all these phenomenons being instrumental in fighting off an infectious menace. Oxidized lipids (including oxysterols and lysophosphatidylcholine) resulting from the oxidation of lipoproteins close to sites of infection and inflammation are disseminated through the circulatory system and act as alarm signals at arterial walls, promoting the penetration and retention of lipoproteins in the intimal tissue of the most susceptible segments of the arterial network. Oxidized lipids in the intima constitute part of first-line antimicrobial defences and their presence acts as a signal to immune effector cells (notably macrophages and lymphocytes) which trigger the acquired immune response when foreign antigens are encountered.
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Affiliation(s)
- H Le Brazidec
- Centre Medical Charles De Gaulle, Department of Cardiology, 78 rue de Brement, 93130 Noisy le Sec, France.
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18
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Rosengren B, Jönsson-Rylander AC, Peilot H, Camejo G, Hurt-Camejo E. Distinctiveness of secretory phospholipase A2 group IIA and V suggesting unique roles in atherosclerosis. Biochim Biophys Acta Mol Cell Biol Lipids 2006; 1761:1301-8. [PMID: 17070102 DOI: 10.1016/j.bbalip.2006.06.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Revised: 06/27/2006] [Accepted: 06/29/2006] [Indexed: 01/26/2023]
Abstract
Clinical observations strongly support an association of circulating levels of secretory phospholipases A(2) (sPLA(2)) in atherosclerotic cardiovascular disease (ACVD). Two modes of action can provide causal support for these statistical correlations. One is the action of the enzymes on circulating lipoproteins and the other is direct action on the lipoproteins once in the arterial extracellular intima. In this review we discuss results suggesting a distinct profile of characteristics related to localization, action on plasma lipoproteins and interaction with arterial proteoglycans for sPLA(2)-IIA and sPLA(2)-V. The differences observed indicate that these enzymes may contribute to atherosclerosis through dissimilar pathways. Furthermore, we comment on recent animal studies from our laboratory indicating that the expression of type V enzyme is up-regulated by genetically and nutritionally-induced dyslipidemias but not the group type IIA enzyme, which is well known to be up-regulated by acute inflammation. The results suggest that if similar up-regulation occurs in humans in response to hyperlipidemia, it may create a distinctive link between the group V enzyme and the disease.
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19
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Rosengren B, Peilot H, Umaerus M, Jönsson-Rylander AC, Mattsson-Hultén L, Hallberg C, Cronet P, Rodriguez-Lee M, Hurt-Camejo E. Secretory Phospholipase A
2
Group V. Arterioscler Thromb Vasc Biol 2006; 26:1579-85. [PMID: 16601231 DOI: 10.1161/01.atv.0000221231.56617.67] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Objective—
To study the distribution of group V secretory phospholipase A
2
(sPLA
2
) in human and mouse lesions and compare its expression by human vascular cells, its activity toward lipoproteins, and the interaction with arterial proteoglycans (proteoglycans) with those of sPLA
2
-IIA. In addition, we also investigated the effect of a Western diet and lipopolysaccharide challenge on the aortic expression of these enzymes in mouse models.
Methods and Results—
Immunohistochemistry showed sPLA
2
-V in human and mouse lesions to be associated with smooth muscle cells and also surrounding foam cells in lipid core areas. mRNA of the enzyme was expressed in human lesions and human vascular cells, supporting the immunohistochemistry data. sPLA
2
-V but not sPLA
2
-IIA was active on lipoproteins in human serum. The association with proteoglycans enhanced 2- to 3-fold sPLA
2
-V activity toward low-density lipoproteins but not that of the group IIA enzyme. Experiments in mouse models showed that treatment with a Western diet induced expression of sPLA
2
-V but not that of sPLA
2
-IIA in aorta. On the other hand, lipopolysaccharide-induced acute inflammation augmented the expression of sPLA
2
-IIA but not that of sPLA
2
-V.
Conclusions—
These results indicate that these phospholipases could have different roles in atherosclerosis.
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20
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Chang MY, Han CY, Wight TN, Chait A. Antioxidants inhibit the ability of lysophosphatidylcholine to regulate proteoglycan synthesis. Arterioscler Thromb Vasc Biol 2005; 26:494-500. [PMID: 16357313 DOI: 10.1161/01.atv.0000200135.61362.27] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE We previously have shown that lysophosphatidylcholine (lysoPC) regulates proteoglycan synthesis by vascular smooth muscle cells (SMCs). Given the accumulating evidence for reactive oxygen species (ROS) as mediators of a variety of effects of lysoPC, the present study evaluates the potential role of ROS as intermediate molecules in the regulation of proteoglycan synthesis by lysoPC. METHODS AND RESULTS LysoPC (10 micromol/L) was found to stimulate rapid and sustained generation of ROS by SMC, as indicated using a fluorescent probe for measuring intracellular oxidants and fluorescence-activated cell sorting. This was not associated with cytotoxicity, as evaluated by fluorescence microscopy using MitoTracker Red or propidium iodide, cell number, cell protein, or lactate dehydrogenase release. Pretreatment with catalase or superoxide dismutase, specific scavengers of hydrogen peroxide and superoxide, respectively, blocked the ability of lysoPC to stimulate both accumulation of ROS and proteoglycan synthesis. Most importantly, these enzymatic antioxidants prevented lysoPC from stimulating the synthesis of proteoglycans with enhanced lipoprotein-binding properties, as quantified by a gel shift binding assay. CONCLUSIONS These findings strongly suggest that ROS are key mediators in the ability of lysoPC to regulate proteoglycan synthesis and that these effects can be inhibited by antioxidants.
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Affiliation(s)
- Mary Y Chang
- Department of Medicine, University of Washington, Seattle, WA 98195-6426, USA.
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21
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Macphee C, Benson GM, Shi Y, Zalewski A. Lipoprotein-associated phospholipase A2: a novel marker of cardiovascular risk and potential therapeutic target. Expert Opin Investig Drugs 2005; 14:671-9. [PMID: 16004595 DOI: 10.1517/13543784.14.6.671] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Although the clinical benefit of statins is well established, these agents reduce the risk of cardiovascular events by only 20 - 40%, and the residual risk for high-risk patients is considerable. The recognition of atherosclerosis as an inflammatory disease has opened the door to numerous complementary therapeutic approaches to further reduce risk and the overall burden of cardiovascular disease. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a novel inflammatory marker of cardiovascular risk that is being evaluated as a potential therapeutic target. The biological function of this enzyme in atherosclerosis has been controversial but recent evidence supports its pro-atherogenic role. The enzyme is predominantly bound to low-density lipoprotein cholesterol particles in humans, and its activity produces bioactive lipid mediators that promote inflammatory processes present at every stage of atherogenesis, from atheroma initiation to plaque destabilisation and rupture. Initial clinical studies suggest that the inhibitors of Lp-PLA(2) can block enzyme activity in plasma and within atherosclerotic plaques. However, more studies are needed to determine the potential clinical benefits of inhibiting Lp-PLA(2).
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Affiliation(s)
- Colin Macphee
- GlaxoSmithKline, Vascular Biology and Thrombosis, 709 Swedeland Road, King of Prussia, PA 19406, USA.
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22
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Lindholm MW, Nilsson J, Moses J. Low density lipoprotein stimulation of human macrophage proteoglycan secretion. Biochem Biophys Res Commun 2005; 328:455-60. [PMID: 15694369 DOI: 10.1016/j.bbrc.2005.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Indexed: 11/19/2022]
Abstract
Lipoprotein trapping in arterial intima increases the risk for lipoprotein oxidation, foam cell formation, and inflammatory response in surrounding cells. Modified lipoproteins increase smooth muscle cell production of proteoglycans likely to retain lipoproteins in intimal extracellular matrix. We hypothesized that macrophage proteoglycan production is regulated in a similar manner, and characterized glycosaminoglycan side chains of secreted proteoglycans. Incubation with native low density lipoproteins (LDL) strongly stimulates total proteoglycan secretion in a time and concentration dependent manner. The main secretion product is small-sized (120 kDa) with unusually long galactosaminoglycan chains, predominantly chondroitin-6-O-sulfated. The effect appears specific for native LDL; oxidized LDL, very low density lipoproteins or phospholipid liposomes have only minor effects compared to control. These observations suggest that native LDL stimulate macrophages to secrete a chondroitin sulfate-rich proteoglycan moiety likely to have high capacity for vascular extracellular trapping of apolipoprotein B-containing lipoproteins.
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Affiliation(s)
- Marie Wickström Lindholm
- Department of Medicine, Lund University, Wallenberg Laboratory Plan 1, UMAS Ing. 46, 20502 Malmö, Sweden
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23
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Williams KJ, Fisher EA. Oxidation, lipoproteins, and atherosclerosis: which is wrong, the antioxidants or the theory? Curr Opin Clin Nutr Metab Care 2005; 8:139-46. [PMID: 15716791 DOI: 10.1097/00075197-200503000-00006] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE OF REVIEW Paradoxically, many well-established components of the heart-healthy lifestyle are pro-oxidant, including polyunsaturated fat and moderate alcohol consumption. Moreover, antioxidant supplements have failed to decrease cardiovascular risk in extensive human clinical trials to date. Recent progress in understanding the roles of oxidants in regulating VLDL secretion and as essential signaling molecules supports the concept that oxidation may be beneficial in certain circumstances but damaging in others. We summarize recent data on the roles played by oxidative metabolism in different tissues and pathways, and address whether it is currently advisable to use antioxidant supplements to reduce cardiovascular risk. RECENT FINDINGS Our recent study reported that in liver cells, polyunsaturated fatty acids increased reactive oxygen species, which in turn lowered the secretion of the atherogenic lipoprotein, VLDL, in vitro and in vivo. Antioxidant treatments prevented VLDL-lowering effects of polyunsaturated fatty acids in vitro, suggesting that supplemental antioxidants could either raise apolipoprotein-B-lipoprotein plasma levels in vivo, or impair the response to lipid-lowering therapies. The failure of antioxidants to decrease cardiovascular disease risk in many trials is also discussed in the context of current models for atherosclerosis progression and regression. SUMMARY Oxidation includes distinct biochemical reactions, and it is overly simplistic to lump them into a unitary process that affects all cell types and metabolic pathways adversely. Guidelines for diet should adhere closely to what has been clinically proved, and by this standard there is no basis to recommend antioxidant use, beyond what is inherent to the 'heart healthy' diet in order to benefit cardiovascular health.
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Affiliation(s)
- Kevin Jon Williams
- Division of Endocrinology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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24
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Chait A, Han CY, Oram JF, Heinecke JW. Thematic review series: The Immune System and Atherogenesis. Lipoprotein-associated inflammatory proteins: markers or mediators of cardiovascular disease? J Lipid Res 2005; 46:389-403. [PMID: 15722558 DOI: 10.1194/jlr.r400017-jlr200] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In humans, a chronically increased circulating level of C-reactive protein (CRP), a positive acute-phase reactant, is an independent risk factor for cardiovascular disease. This observation has led to considerable interest in the role of inflammatory proteins in atherosclerosis. In this review, after discussing CRP, we focus on the potential role in the pathogenesis of human vascular disease of inflammation-induced proteins that are carried by lipoproteins. Serum amyloid A (SAA) is transported predominantly on HDL, and levels of this protein increase markedly during acute and chronic inflammation in both animals and humans. Increased SAA levels predict the risk of cardiovascular disease in humans. Recent animal studies support the proposal that SAA plays a role in atherogenesis. Evidence is accruing that secretory phospholipase A(2), an HDL-associated protein, and platelet-activating factor acetylhydrolase, a protein associated predominantly with LDL in humans and HDL in mice, might also play roles both as markers and mediators of human atherosclerosis. In contrast to positive acute-phase proteins, which increase in abundance during inflammation, negative acute-phase proteins have received less attention. Apolipoprotein A-I (apoA-I), the major apolipoprotein of HDL, decreases during inflammation. Recent studies also indicate that HDL is oxidized by myeloperoxidase in patients with established atherosclerosis. These alterations may limit the ability of apoA-I to participate in reverse cholesterol transport. Paraoxonase-1 (PON1), another HDL-associated protein, also decreases during inflammation. PON1 is atheroprotective in animal models of hypercholesterolemia. Controversy over its utility as a marker of human atherosclerosis may reflect the fact that enzyme activity rather than blood level (or genotype) is the major determinant of cardiovascular risk. Thus, multiple lipoprotein-associated proteins that change in concentration during acute and chronic inflammation may serve as markers of cardiovascular disease. In future studies, it will be important to determine whether these proteins play a causal role in atherogenesis.
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Affiliation(s)
- Alan Chait
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, University of Washington, Seattle, WA 98195, USA.
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25
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Zalewski A, Macphee C. Role of lipoprotein-associated phospholipase A2 in atherosclerosis: biology, epidemiology, and possible therapeutic target. Arterioscler Thromb Vasc Biol 2005; 25:923-31. [PMID: 15731492 DOI: 10.1161/01.atv.0000160551.21962.a7] [Citation(s) in RCA: 349] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The development of atherosclerotic vascular disease is invariably linked to the formation of bioactive lipid mediators and accompanying vascular inflammation. Lipoprotein-associated phospholipase A2 (Lp-PLA2) is an enzyme that is produced by inflammatory cells, co-travels with circulating low-density lipoprotein (LDL), and hydrolyzes oxidized phospholipids in LDL. Its biological role has been controversial with initial reports purporting atheroprotective effects of Lp-PLA2 thought to be a consequence of degrading platelet-activating factor and removing polar phospholipids in modified LDL. Recent studies, however, focused on pro-inflammatory role of Lp-PLA2 mediated by products of the Lp-PLA2 reaction (lysophosphatidylcholine and oxidized nonesterified fatty acids). These bioactive lipid mediators, which are generated in lesion-prone vasculature and to a lesser extent in the circulation (eg, in electronegative LDL), are known to elicit several inflammatory responses. The proinflammatory action of Lp-PLA2 is also supported by a number of epidemiology studies suggesting that the circulating level of the enzyme is an independent predictor of cardiovascular events, despite some attenuation of the effect by inclusion of LDL, the primary carrier of Lp-PLA2, in the analysis. These observations provide a rationale to explore whether inhibiting Lp-PLA2 activity and consequent interference with the formation of bioactive lipid mediators will abrogate inflammation associated with atherosclerosis, produce favorable changes in intermediate cardiovascular end points (eg, biomarkers, imaging, and endothelial function), and ultimately reduce cardiovascular events in high-risk patients.
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Affiliation(s)
- Andrew Zalewski
- Medicine Development Centre, GlaxoSmithKline, Philadelphia, Pa, USA.
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26
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Khalil MF, Wagner WD, Goldberg IJ. Molecular interactions leading to lipoprotein retention and the initiation of atherosclerosis. Arterioscler Thromb Vasc Biol 2004; 24:2211-8. [PMID: 15472124 DOI: 10.1161/01.atv.0000147163.54024.70] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Atherosclerosis is distinguished by the accumulation of lipoprotein lipid within the arterial wall. An ionic interaction of positively charged regions of apolipoprotein (apo) B with matrix proteins, including proteoglycans, collagen, and fibronectin, is thought to initiate this process. Proteoglycans are complex glycoproteins containing highly negatively charged carbohydrate chains. These proteins are abundant in atherosclerosis lesions, and they associate with apoB-containing lipoproteins. Several specific regions of apoB may mediate this process. Other lipoprotein-associated proteins, including apoE and lipases, might also participate in this process. In addition, retention may occur via lipoprotein association with other matrix molecules or as a consequence of intra-arterial lipoprotein aggregation.
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Affiliation(s)
- Maged F Khalil
- Division of Preventive Medicine & Nutrition, Columbia University, New York, NY 10032, USA
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27
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Abstract
PURPOSE OF REVIEW Considerable evidence suggests that the subendothelial retention of atherogenic lipoproteins is a key early step in atherogenesis. In humans and experimental animals, elevated levels of plasma lipoproteins are associated with increased atherosclerosis, and lipoproteins with higher affinity for arterial proteoglycans are more atherogenic. Here we discuss the molecular mechanisms underlying lipoprotein retention in the arterial wall and how this interaction can be modulated. RECENT FINDINGS Functional proteoglycan binding sites in lipoproteins containing apolipoprotein B have been identified and shown to have atherogenic potential in vivo. In addition to apolipoprotein B, novel bridging molecules, those that can interact with both proteoglycans and lipoproteins, have been identified that mediate the retention of atherogenic particles in the vessel wall. The interaction between lipoproteins and proteoglycans can be enhanced by the modification of lipoproteins in the circulation and in the arterial wall, by alterations in the subendothelium, and by changes in proteoglycan synthesis that result in a more atherogenic profile. The retention of atherogenic lipoproteins is a potential target for therapies to reverse atherosclerosis, and in-vitro studies have identified compounds that decrease the affinity of proteoglycans for lipoproteins. SUMMARY Considerable progress has been made in understanding the association between lipoproteins and cardiovascular disease. This review highlights the importance of the interaction between lipoproteins and the arterial matrix.
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Affiliation(s)
- Maria Gustafsson
- Wallenberg Laboratory for Cardiovascular Research and the Cardiovascular Institute, The Sahlgrenska Academy at Göteborg University, 413 45 Göteborg, Sweden.
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