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Reddy S, Rao K R, Kashyap JR, Kadiyala V, Kumar S, Dash D, Uppal L, Kaur J, Kaur M, Reddy H, Rather IIG, Malhotra S. Association of non-HDL cholesterol with plaque burden and composition of culprit lesion in acute coronary syndrome. An intravascular ultrasound-virtual histology study. Indian Heart J 2024:S0019-4832(24)00187-1. [PMID: 39389260 DOI: 10.1016/j.ihj.2024.10.004] [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: 09/08/2023] [Revised: 08/05/2024] [Accepted: 10/06/2024] [Indexed: 10/12/2024] Open
Abstract
OBJECTIVE Lipids play key role in coronary atherosclerosis. The role of non-high-density lipoprotein cholesterol (non-HDL-C) in atherosclerotic plaques using intravascular imaging remains unclear. This study aimed to assess its relationship with coronary plaque features using intravascular ultrasound (IVUS) in acute coronary syndrome (ACS). METHODS A total of 601 patients divided into two groups: normal non-HDL-C≤130 mg/dl (n = 410) and high non-HDL cholesterol >130 mg/dl (n = 191). IVUS performed before coronary intervention. RESULTS Mean age 53.18 ± 12.29 years. No significant differences in hypertension, diabetes, and smoking between groups. Plaque burden was significantly higher among normal versus high non-HDL-C groups (79.59 ± 9.98 % vs. 81.61 ± 5.39 %; p = 0.001). At minimal luminal site, fibrofatty percentage was higher in normal non-HDL-C group (p = 0.027), while necrotic core greater in high non-HDL-C group (p = 0.033). Segmental analysis, necrotic core was significantly higher in percentage (p = 0.006) and volumes (p = 0.011) in normal versus high non-HDL-C groups. Total cholesterol (r = 0.099, p = 0.015), LDL-C (r = 0.081, p = 0.046), triglycerides (r = 0.083, p = 0.041),and non-HDL-C (r = 0.099, p = 0.015) positively correlated with plaque burden. Total cholesterol (r = 0.115, p = 0.005), LDL-C (r = 0.107, p = 0.009), and non-HDL-C (r = 0.105, p = 0.010) positively correlated with necrotic core volume. Linear regression analysis showed age and non-HDL-C as predictors of higher plaque burden. Multiple linear regression analysis; age, body mass index, and non-HDL-C were predictors of larger necrotic core volume. CONCLUSION Non-HDL-C levels were positively associated with plaque burden, measure of extent of atherosclerosis. It is closely associated with and is a predictor of necrotic core volume; a marker of plaque vulnerability. This IVUS study demonstrates potential role of non-HDL-C in causation of plaque in ACS.
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Affiliation(s)
- Sreenivas Reddy
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Raghavendra Rao K
- Department of Cardiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
| | - Jeet Ram Kashyap
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Vikas Kadiyala
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Suraj Kumar
- Department of Cardiology, All India Institute of Medical Sciences, Bhatinda, India.
| | | | - Lipi Uppal
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Jaspreet Kaur
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Manpreet Kaur
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Hithesh Reddy
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Imran Ibni Gani Rather
- Department of Cardiology, Government Medical College and Hospital, Sector 32, Chandigarh, 160030, India.
| | - Samir Malhotra
- Department of Pharmacology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, 160012, India.
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Swertfeger DK, Rebholz S, Li H, Shah AS, Davidson WS, Lu LJ. Feasibility of a plasma bioassay to assess oxidative protection of low-density lipoproteins by high-density lipoproteins. J Clin Lipidol 2018; 12:1539-1548. [PMID: 30244943 PMCID: PMC6437770 DOI: 10.1016/j.jacl.2018.08.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/30/2018] [Accepted: 08/15/2018] [Indexed: 02/04/2023]
Abstract
BACKGROUND Traditionally, the impact of lipoproteins on vascular disease has been evaluated in light of their quantity, that is, cholesterol content, in plasma. However, recent studies of high-density lipoproteins (HDLs) have focused on functionality with regard to atheroprotection. For example, bioassays have emerged to assess the ability of HDL, in its near native plasma environment, to promote cholesterol removal (efflux) from cells. As a result, attention has focused on developing plasma-based assays for other putative HDL protective functions including protecting low-density lipoproteins (LDLs) from oxidative damage. OBJECTIVE To determine the feasibility of such an assay in a complex sample such as plasma, we evaluated the contribution of HDL vs other plasma factors in preventing LDL oxidation. METHODS We separated normolipidemic human plasma by gel filtration chromatography and assessed each fraction for its ability to prevent LDL modification by water soluble radical and copper-initiated oxidation mechanisms. RESULTS Using proteomics and selective precipitation methods, we identified major antioxidative contributions for fibrinogen, immunoglobulin G, albumin, and small soluble molecules like uric acid and ascorbate, with albumin being especially dominant in copper-initiated mechanisms. HDL particles were minor contributors (∼1%-2%) to the antioxidant capacity of plasma, irrespective of oxidation mechanism. CONCLUSIONS Given the overwhelming background of antioxidant capacity inherent to highly abundant plasma proteins, specific bioassays of HDL antioxidative function will likely require its complete separation from plasma.
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Affiliation(s)
- Debi K Swertfeger
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Sandra Rebholz
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA; Department of Pathology and Laboratory Medicine, Center for Lipid and Arteriosclerosis Science, University of Cincinnati, Cincinnati, OH, USA
| | - Hailong Li
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - Amy S Shah
- Division of Endocrinology, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
| | - William Sean Davidson
- Department of Pathology and Laboratory Medicine, Center for Lipid and Arteriosclerosis Science, University of Cincinnati, Cincinnati, OH, USA.
| | - Long J Lu
- Division of Biomedical Informatics, Cincinnati Children's Hospital Research Foundation, Cincinnati, OH, USA
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3
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Sun QA, Runge MS, Madamanchi NR. Oxidative stress, NADPH oxidases, and arteries. Hamostaseologie 2015; 36:77-88. [PMID: 25649240 DOI: 10.5482/hamo-14-11-0076] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 01/21/2015] [Indexed: 02/07/2023] Open
Abstract
Atherosclerosis and its major complications - myocardial infarction and stroke - remain major causes of death and disability in the United States and world-wide. Indeed, with dramatic increases in obesity and diabetes mellitus, the prevalence and public health impact of cardiovascular diseases (CVD) will likely remain high. Major advances have been made in development of new therapies to reduce the incidence of atherosclerosis and CVD, in particular for treatment of hypercholesterolemia and hypertension. Oxidative stress is the common mechanistic link for many CVD risk factors. However, only recently have the tools existed to study the interface between oxidative stress and CVD in animal models. The most important source of reactive oxygen species (and hence oxidative stress) in vascular cells are the multiple forms of enzymes nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase). Recently published and emerging studies now clearly establish that: 1) NADPH oxidases are of critical importance in atherosclerosis and hypertension in animal models; 2) given the tissue-specific expression of key components of NADPH oxidase, it may be possible to target vascular oxidative stress for prevention of CVD.
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Affiliation(s)
| | - Marschall S Runge
- Marschall S. Runge, MD PhD, Department of Medicine, 125 MacNider Hall, University of North Carolina, Chapel Hill, NC 27599-7005, USA, E-mail:
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4
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Falk E, Nakano M, Bentzon JF, Finn AV, Virmani R. Update on acute coronary syndromes: the pathologists' view. Eur Heart J 2012; 34:719-28. [PMID: 23242196 DOI: 10.1093/eurheartj/ehs411] [Citation(s) in RCA: 699] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although mortality rates from coronary heart disease in the western countries have declined in the last few decades, morbidity caused by this disease is increasing and a substantial number of patients still suffer acute coronary syndrome (ACS) and sudden cardiac death. Acute coronary syndrome occurs as a result of myocardial ischaemia and its manifestations include acute myocardial infarction and unstable angina. Culprit plaque morphology in these patients varies from thrombosis with or without coronary occlusion to sudden narrowing of the lumen from intraplaque haemorrhage. The coronary artery plaque morphologies primarily responsible for thrombosis are plaque rupture, and plaque erosion, with plaque rupture being the most common cause of acute myocardial infarction, especially in men. Autopsy data demonstrate that women <50 years of age more frequently have erosion, whereas in older women, the frequency of rupture increases with each decade. Ruptured plaques are associated with positive (expansive) remodelling and characterized by a large necrotic core and a thin fibrous cap that is disrupted and infiltrated by foamy macrophages. Plaque erosion lesions are often negatively remodelled with the plaque itself being rich in smooth muscle cells and proteoglycans with minimal to absence of inflammation. Plaque haemorrhage may expand the plaque rapidly, leading to the development of unstable angina. Plaque haemorrhage may occur from plaque rupture (fissure) or from neovascularization (angiogenesis). Atherosclerosis is now recognized as an inflammatory disease with macrophages and T-lymphocytes playing a dominant role. Recently at least two subtypes of macrophages have been identified. M1 is a pro-inflammatory macrophage while M2 seems to play a role in dampening inflammation and promoting tissue repair. A third type of macrophage, termed by us as haemoglobin associated macrophage or M(Hb) which is observed at site of haemorrhage also can be demonstrated in human atherosclerosis. In order to further our understanding of the specific biological events which trigger plaque instability and as well as to monitor the effects of novel anti-atherosclerotic therapies newer imaging modalities in vivo are needed.
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Affiliation(s)
- Erling Falk
- Aarhus University Hospital Skejby, Aarhus, Denmark
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5
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Jayaraman S, Gantz DL, Gursky O. Effects of phospholipase A(2) and its products on structural stability of human LDL: relevance to formation of LDL-derived lipid droplets. J Lipid Res 2011; 52:549-57. [PMID: 21220788 DOI: 10.1194/jlr.m012567] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hydrolysis and oxidation of LDL stimulate LDL entrapment in the arterial wall and promote inflammation and atherosclerosis via various mechanisms including lipoprotein fusion and lipid droplet formation. To determine the effects of FFA on these transitions, we hydrolyzed LDL by phospholipase A(2) (PLA(2)), removed FFA by albumin, and analyzed structural stability of the modified lipoproteins. Earlier, we showed that heating induces LDL remodeling, rupture, and coalescence into lipid droplets resembling those found in atherosclerotic lesions. Here, we report how FFA affect these transitions. Circular dichroism showed that mild LDL lipolysis induces partial β-sheet unfolding in apolipoprotein B. Electron microscopy, turbidity, and differential scanning calorimetry showed that mild lipolysis promotes LDL coalescence into lipid droplets. FFA removal by albumin restores LDL stability but not the protein conformation. Consequently, FFA enhance LDL coalescence into lipid droplets. Similar effects of FFA were observed in minimally oxidized LDL, in LDL enriched with exogenous FFA, and in HDL and VLDL. Our results imply that FFA promote lipoprotein coalescence into lipid droplets and explain why LDL oxidation enhances such coalescence in vivo but hampers it in vitro. Such lipid droplet formation potentially contributes to the pro-atherogenic effects of FFA.
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Affiliation(s)
- Shobini Jayaraman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA.
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6
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Guyton JR. Combination regimens with statin, niacin, and intestinally active LDL-lowering drugs: alternatives to high-dose statin therapy? Curr Opin Lipidol 2010; 21:372-7. [PMID: 20625257 DOI: 10.1097/mol.0b013e32833c1f16] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW To summarize recent studies on combination regimens that employ a statin with added niacin, ezetimibe, and/or bile acid sequestrants, and to understand the implications of these studies for clinical practice. RECENT FINDINGS Combinations of statin, niacin, and/or intestinally active LDL-lowering drug have demonstrated safety and favorable effects on plasma low and high-density lipoproteins. Niacin and bile acid sequestrants appear to exert beneficial effects on atherosclerotic lesions, whereas results with ezetimibe are uncertain. Moreover, the use of niacin and bile acid sequestrants is supported by clinical outcome results from large monotherapy trials and small combination therapy trials. Three large randomized trials currently are evaluating clinical outcomes with the addition of niacin or ezetimibe to statin treatment. SUMMARY Until the results of ongoing trials are known, it is reasonable to favor the use of niacin and bile acid sequestrants in combination with statins, based on safety and efficacy with regard to effects on lipoproteins, atherosclerotic lesions, and, to a limited extent, clinical outcomes. The effect of ezetimibe on carotid atherosclerosis is indeterminate, but ezetimibe can be reasonably added to statin therapy as a secondary option for LDL-lowering.
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Affiliation(s)
- John R Guyton
- Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA.
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7
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Bot M, Bot I, Lopez-Vales R, van de Lest CHA, Saulnier-Blache JS, Helms JB, David S, van Berkel TJC, Biessen EAL. Atherosclerotic lesion progression changes lysophosphatidic acid homeostasis to favor its accumulation. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 176:3073-84. [PMID: 20431029 DOI: 10.2353/ajpath.2010.090009] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lysophosphatidic acid (LPA) accumulates in the central atheroma of human atherosclerotic plaques and is the primary platelet-activating lipid constituent of plaques. Here, we investigated the enzymatic regulation of LPA homeostasis in atherosclerotic lesions at various stages of disease progression. Atherosclerotic lesions were induced in carotid arteries of low-density lipoprotein receptor-deficient mice by semiconstrictive collar placement. At 2-week intervals after collar placement, lipids and RNA were extracted from the vessel segments carrying the plaque. Enzymatic-and liquid chromatography-mass spectrometry-based lipid profiling revealed progressive accumulation of LPA species in atherosclerotic tissue preceded by an increase in lysophosphatidylcholine, a precursor in LPA synthesis. Plaque expression of LPA-generating enzymes cytoplasmic phospholipase A(2)IVA (cPLA(2)IVA) and calcium-independent PLA(2)VIA (iPLA(2)VIA) was gradually increased, whereas that of the LPA-hydrolyzing enzyme LPA acyltransferase alpha was quenched. Increased expression of cPLA(2)IVA and iPLA(2)VIA in advanced lesions was confirmed by immunohistochemistry. Moreover, LPA receptors 1 and 2 were 50% decreased and sevenfold upregulated, respectively. Therefore, key proteins in LPA homeostasis are increasingly dysregulated in the plaque during atherogenesis, favoring intracellular LPA production. This might at least partly explain the observed progressive accumulation of this thrombogenic proinflammatory lipid in human and mouse plaques. Thus, intervention in the enzymatic LPA production may be an attractive measure to lower intraplaque LPA content, thereby reducing plaque progression and thrombogenicity.
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Affiliation(s)
- Martine Bot
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
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8
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Jönsson-Rylander AC, Lundin S, Rosengren B, Pettersson C, Hurt-Camejo E. Role of secretory phospholipases in atherogenesis. Curr Atheroscler Rep 2008; 10:252-9. [PMID: 18489854 DOI: 10.1007/s11883-008-0039-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Elevated circulating levels of secretory phospholipase A(2) (sPLA(2)) are associated with atherosclerotic cardiovascular disease. sPLA(2) can contribute to atherogenesis by hydrolyzing phospholipids of circulating lipoproteins and lipoproteins entrapped in the arterial wall and/or in cells that reside in the intima and that participate in the inflammatory response to lipoprotein deposition. This article reviews differences and similarities between sPLA(2)-IIA, sPLA(2)-V, and sPLA(2)-X, all of which are members of this family of enzymes with reported potential proatherogenic features. Published data suggest that each of the enzymes has a distinct profile characterized by differences in tissue expression and localization, capacity to act on phospholipids of cell membranes and lipoproteins, and their interaction with arterial proteoglycans. In addition, the article discusses results from the authors' laboratory showing that diet-induced or gene-induced hyperlipidemia in mice enhances the expression of sPLA(2)-V in different tissues, but not sPLA(2)-IIA. Such differences indicate that these enzymes may have different roles in atherosclerotic cardiovascular disease through their distinct profiles.
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Affiliation(s)
- Ann-Cathrine Jönsson-Rylander
- AstraZeneca, R&D, Bioscience, Mölndal S-431 83, Wallenberg Laboratory for Cardiovascular Research, Sahlgrenska University Hospital, Gotheburg, Sweden
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9
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Abstract
Plaque rupture precipitates approximately 75% of all fatal coronary thrombi. Therefore, the plaque prone to rupture is the primary focus of this review. The lipid-rich core and fibrous cap are pivotal in the understanding of plaque rupture. Plaque rupture is a localized process within the plaque caused by degradation of a tiny fibrous cap rather than by diffuse inflammation of the plaque. Atherosclerosis is a multifocal disease, but plaques prone to rupture seem to be oligofocal at most.
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Affiliation(s)
- T Thim
- Atherosclerosis Research Unit, Department of Cardiology, Aarhus University Hospital (Skejby), Aarhus, Denmark.
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10
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Kolodgie FD, Burke AP, Nakazawa G, Cheng Q, Xu X, Virmani R. Free cholesterol in atherosclerotic plaques: where does it come from? Curr Opin Lipidol 2007; 18:500-7. [PMID: 17885419 DOI: 10.1097/mol.0b013e3282efa35b] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
PURPOSE OF REVIEW Free cholesterol in plaques is an emerging contributing factor to lesion instability and, until recently, apoptosis of lipid-laden macrophages was considered the major source of free cholesterol. The validity of this concept is beginning to be challenged since there is recent evidence of erythrocyte membrane-derived cholesterol in plaques. Therefore, intraplaque hemorrhage may not be a passive event, as once considered as studies continue to support the relationship of intraplaque hemorrhage and necrotic core expansion. RECENT FINDINGS The association of intraplaque hemorrhage, accumulated free cholesterol, and necrotic core expansion is beginning to unfold and recent MRI studies suggest the value of intraplaque hemorrhage as a predictor of recurrent cerebrovascular events. The amount of erythrocyte membrane-derived cholesterol is also suggested to be a measure of lesion vulnerability in acute coronary syndromes. Recent inhibitors studies of vascular permeability factors further emphasize the importance of intraplaque hemorrhage in plaque progression. Finally, DNA microarray analysis is starting to reveal key molecules involved in the accumulation of free cholesterol that are selectively induced in high-risk plaques. SUMMARY These recent findings emphasize the importance of intraplaque hemorrhage as a contributor of free cholesterol in plaques and point to its provocative role in lesion destabilization.
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Leclercq A, Houard X, Loyau S, Philippe M, Sebbag U, Meilhac O, Michel JB. Topology of protease activities reflects atherothrombotic plaque complexity. Atherosclerosis 2006; 191:1-10. [PMID: 16713600 DOI: 10.1016/j.atherosclerosis.2006.04.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 03/27/2006] [Accepted: 04/04/2006] [Indexed: 11/26/2022]
Abstract
The pathological remodeling of the arterial wall in atherosclerosis involves protease activities, which play a major role in complications, through plaque rupture. Here, we investigated the release of active proteases by human carotid plaques in relation to (1) the degree of lesion complexity and (2) their compartmentalization between cap, core and media. Eighty human carotid endarterectomy specimens were dissected into culprit stenosing (CPs) and adjacent non-complicated/non-stenosing plaques (NPs). Thirty-five additional CPs were microdissected into cap, core and media. All specimens were compared to control non-atherosclerotic endarteries for the release of components of the plasminogen/plasmin system and matrix metalloproteinases (MMPs). Results show a greater release of the plasminogen activators (PAs), plasmin and active MMPs by CPs compared to NPs, whereas healthy arteries released even lower levels. Furthermore, we highlight a functional interaction between these proteases in human atherosclerotic tissues and more importantly, we demonstrate that the core constitutes the main source of protease activities within CPs. Together, these results suggest that CPs generate plasmin, mainly in the core, which could in turn participate in MMP activation and the onset of complications.
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12
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Falk E. Pathogenesis of atherosclerosis. J Am Coll Cardiol 2006; 47:C7-12. [PMID: 16631513 DOI: 10.1016/j.jacc.2005.09.068] [Citation(s) in RCA: 915] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2005] [Revised: 09/12/2005] [Accepted: 09/19/2005] [Indexed: 01/17/2023]
Abstract
Atherosclerosis is a multifocal, smoldering, immunoinflammatory disease of medium-sized and large arteries fuelled by lipids. Endothelial cells, leukocytes, and intimal smooth muscle cells are the major players in the development of this disease. The most devastating consequences of atherosclerosis, such as heart attack and stroke, are caused by superimposed thrombosis. Therefore, the vital question is not why atherosclerosis develops but rather why atherosclerosis, after years of indolent growth, suddenly becomes complicated with luminal thrombosis. If thrombosis-prone plaques could be detected and thrombosis averted, atherosclerosis would be a much more benign disease. Approximately 76% of all fatal coronary thrombi are precipitated by plaque rupture. Plaque rupture is a more frequent cause of coronary thrombosis in men (approximately 80%) than in women (approximately 60%). Ruptured plaques are characterized by a large lipid-rich core, a thin fibrous cap that contains few smooth muscle cells and many macrophages, angiogenesis, adventitial inflammation, and outward remodeling. Plaque rupture is the most common cause of coronary thrombosis. Ruptured plaques and, by inference, rupture-prone plaques have characteristic pathoanatomical features that might be useful for their detection in vivo by imaging. This article describes the pathogenesis of atherosclerosis, how it begets thrombosis, and the possibility to detect thrombosis-prone plaques and prevent heart attack.
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Affiliation(s)
- Erling Falk
- Department of Cardiology, Aarhus University Hospital (Skejby), Aarhus, Denmark.
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13
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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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Miranda PJ, DeFronzo RA, Califf RM, Guyton JR. Metabolic syndrome: evaluation of pathological and therapeutic outcomes. Am Heart J 2005; 149:20-32. [PMID: 15660031 DOI: 10.1016/j.ahj.2004.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Phillippa J Miranda
- Diabetes Division, University of Texas Health Science Center, San Antonio, Tex, USA
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15
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Marathe GK, Zimmerman GA, Prescott SM, McIntyre TM. Activation of vascular cells by PAF-like lipids in oxidized LDL. Vascul Pharmacol 2002; 38:193-200. [PMID: 12449015 DOI: 10.1016/s1537-1891(02)00169-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The components of inflammation, including macrophages, cytokines and lipid inflammatory mediators, have a role in atherosclerosis. A key lipid mediator in regulated, physiologic inflammation is platelet-activating factor (PAF). PAF activates cells, including monocytes, through a single molecularly characterized receptor, the PAF receptor (PAFR), at exceedingly low concentrations. The PAFR recognizes the short residue, an acetate residue, at the 2-position of the phospholipid, and this sharp specificity precludes receptor activation by other related phosphatidylcholines. Oxidation of low-density lipoproteins (LDLs) is an early and causal step in atherosclerosis that generates inflammatory compounds leading to foam cell formation. One class of oxidatively generated inflammatory compounds are phospholipids that structurally mimic PAF, the PAF-like lipids. Oxidation of LDLs fragments and derivatizes the fatty acid residues at the 2-position of the phosphatidylcholines that comprise the shell of LDLs, an event that allows certain oxidized phospholipids to interact with and activate the PAFR. We know that these products activate polymorphonuclear leukocytes, but because the function of the PAFR differs among cells, we do not know if monocytes or platelets themselves respond to PAF-like lipids. Here, we show that PAF-like lipids from oxidized LDLs are potent and serve as specific agonists for all cells that express the PAFR.
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Affiliation(s)
- Gopal K Marathe
- Department of Internal Medicine, Human Molecular Biology and Genetics Program, University of Utah, Salt Lake City, UT 84112, USA
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