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Abstract
PURPOSE OF REVIEW Levels of small, dense low-density lipoprotein (LDL) (sdLDL) particles determined by several analytic procedures have been associated with risk of atherosclerotic cardiovascular disease (ASCVD). This review focuses on the clinical significance of sdLDL measurement. RECENT FINDINGS Results of multiple prospective studies have supported earlier evidence that higher levels of sdLDL are significantly associated with greater ASCVD risk, in many cases independent of other lipid and ASCVD risk factors as well as levels of larger LDL particles. A number of properties of sdLDL vs. larger LDL, including reduced LDL receptor affinity and prolonged plasma residence time as well as greater oxidative susceptibility and affinity for arterial proteoglycans, are consistent with their heightened atherogenic potential. Nevertheless, determination of the extent to which sdLDL can preferentially impact ASCVD risk compared with other apoprotein B-containing lipoproteins has been confounded by their metabolic interrelationships and statistical collinearity, as well as differences in analytic procedures and definitions of sdLDL. SUMMARY A growing body of data points to sdLDL concentration as a significant determinant of ASCVD risk. Although future studies should be aimed at determining the clinical benefit of reducing sdLDL levels, there is sufficient evidence to warrant consideration of sdLDL measurement in assessing and managing risk of cardiovascular disease. VIDEO ABSTRACT https://www.dropbox.com/s/lioohr2ead7yx2p/zoom_0.mp4?dl=0.
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Stadler JT, Wadsack C, Marsche G. Fetal High-Density Lipoproteins: Current Knowledge on Particle Metabolism, Composition and Function in Health and Disease. Biomedicines 2021; 9:biomedicines9040349. [PMID: 33808220 PMCID: PMC8067099 DOI: 10.3390/biomedicines9040349] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol and other lipids carried by lipoproteins play an indispensable role in fetal development. Recent evidence suggests that maternally derived high-density lipoprotein (HDL) differs from fetal HDL with respect to its proteome, size, and function. Compared to the HDL of adults, fetal HDL is the major carrier of cholesterol and has a unique composition that implies other physiological functions. Fetal HDL is enriched in apolipoprotein E, which binds with high affinity to the low-density lipoprotein receptor. Thus, it appears that a primary function of fetal HDL is the transport of cholesterol to tissues as is accomplished by low-density lipoproteins in adults. The fetal HDL-associated bioactive sphingolipid sphingosine-1-phosphate shows strong vasoprotective effects at the fetoplacental vasculature. Moreover, lipoprotein-associated phospholipase A2 carried by fetal-HDL exerts anti-oxidative and athero-protective functions on the fetoplacental endothelium. Notably, the mass and activity of HDL-associated paraoxonase 1 are about 5-fold lower in the fetus, accompanied by an attenuation of anti-oxidative activity of fetal HDL. Cholesteryl ester transfer protein activity is reduced in fetal circulation despite similar amounts of the enzyme in maternal and fetal serum. This review summarizes the current knowledge on fetal HDL as a potential vasoprotective lipoprotein during fetal development. We also provide an overview of whether and how the protective functionalities of HDL are impaired in pregnancy-related syndromes such as pre-eclampsia or gestational diabetes mellitus.
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Affiliation(s)
- Julia T. Stadler
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
| | - Christian Wadsack
- Department of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria;
| | - Gunther Marsche
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
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Untersteller K, Meissl S, Trieb M, Emrich IE, Zawada AM, Holzer M, Knuplez E, Fliser D, Heine GH, Marsche G. HDL functionality and cardiovascular outcome among nondialysis chronic kidney disease patients. J Lipid Res 2018; 59:1256-1265. [PMID: 29789355 PMCID: PMC6027904 DOI: 10.1194/jlr.p085076] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 05/07/2018] [Indexed: 01/11/2023] Open
Abstract
CVD remains the leading cause of morbidity and mortality in patients with chronic kidney disease (CKD). CKD profoundly affects HDL composition and functionality, but whether abnormal HDL independently contributes to cardiovascular events in CKD patients remains elusive. In the present study, we assessed whether compositional and functional properties of HDL predict cardiovascular outcome among 526 nondialysis CKD patients who participate in the CARE FOR HOMe study. We measured HDL cholesterol, the content of HDL-associated proinflammatory serum amyloid A (SAA), and activities of the HDL enzymes paraoxonase and lipoprotein-associated phospholipase A2 (Lp-PLA2). In addition, we assessed the antioxidative activity of apoB-depleted serum. During a mean follow-up of 5.1 ± 2.1 years, 153 patients reached the predefined primary endpoint, a composite of atherosclerotic cardiovascular events including cardiovascular mortality and death of any cause. In univariate Cox regression analyses, lower HDL-cholesterol levels, higher HDL-associated SAA content, and lower paraoxonase activity predicted cardiovascular outcome, while Lp-PLA2 activity and antioxidative capacity did not. HDL-cholesterol and HDL-paraoxonase activity lost their association with cardiovascular outcome after adjustment for traditional cardiovascular and renal risk factors, while SAA lost its association after further adjustment for C-reactive protein. In conclusion, our data suggest that neither HDL quantity nor HDL composition or function independently predict cardiovascular outcome among nondialysis CKD patients.
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Affiliation(s)
- Kathrin Untersteller
- Internal Medicine IV-Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - Sabine Meissl
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Graz, Austria
| | - Markus Trieb
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Insa E Emrich
- Internal Medicine IV-Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - Adam M Zawada
- Internal Medicine IV-Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - Michael Holzer
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Graz, Austria.,BioTechMed-Graz, Graz, Austria
| | - Eva Knuplez
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Graz, Austria
| | - Danilo Fliser
- Internal Medicine IV-Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - Gunnar H Heine
- Internal Medicine IV-Nephrology and Hypertension, Saarland University Medical Center, Homburg, Germany
| | - Gunther Marsche
- Otto Loewi Research Center, Division of Pharmacology, Medical University of Graz, Graz, Austria .,BioTechMed-Graz, Graz, Austria
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Bacchetti T, Vignini A, Giulietti A, Nanetti L, Provinciali L, Luzzi S, Mazzanti L, Ferretti G. Higher Levels of Oxidized Low Density Lipoproteins in Alzheimer's Disease Patients: Roles for Platelet Activating Factor Acetyl Hydrolase and Paraoxonase-1. J Alzheimers Dis 2016; 46:179-86. [PMID: 25720407 DOI: 10.3233/jad-143096] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Alzheimer's disease (AD) is associated with oxidative damage of low density lipoproteins (ox-LDL). In order to investigate whether higher levels of ox-LDL are related to alterations of the activity of enzymes involved in lipid metabolism, we studied the activity of paraoxonase-1 (PON1) and platelet activating factor acetylhydrolase (PAF-AH) in AD patients and the relationship between biochemical markers and severity of the disease. Levels of ox-LDL, PON1 (paraoxonase, arylesterase, and lactonase activities), and PAF-AH activity were evaluated in plasma from 49 patients affected by AD and from 34 control subjects matched for gender and age. Our results demonstrated alterations in the activities of PON1 and PAF-AH in AD patients compared to controls and showed, for the first time, a relationship between the activities of these enzymes, ox-LDL levels, and severity of the disease. A significant negative correlation was observed between the ratio PON1/PAF-AH and ox-LDL. Whatever the causes that contribute to a systemic oxidative stress in AD, our results have shown that AD patients exhibit higher PAF-AH activity than control subjects and higher ox-LDL. This phenomenon, in combination with diminished PON1 in these patients and, consequently, the relatively lower ratio PON1/PAF-AH activity, could contribute to inflammation and oxidative stress of plasma lipoproteins.
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Affiliation(s)
- Tiziana Bacchetti
- Dipartimento di Scienze della Vita e dell'Ambiente (DISVA), Universitá Politecnica delle Marche, Italy
| | - Arianna Vignini
- Dipartimento di Scienze cliniche Specialistiche ed Odontostomatologiche (DISCO), Universitá Politecnica delle Marche, Italy
| | - Alessia Giulietti
- Dipartimento di Scienze cliniche Specialistiche ed Odontostomatologiche (DISCO), Universitá Politecnica delle Marche, Italy
| | - Laura Nanetti
- Dipartimento di Scienze cliniche Specialistiche ed Odontostomatologiche (DISCO), Universitá Politecnica delle Marche, Italy
| | - Leandro Provinciali
- Dipartimento Medicina Sperimentale e Clinica - Sezione Neuroscienze Cliniche, Universitá Politecnica delle Marche, Italy
| | - Simona Luzzi
- Dipartimento Medicina Sperimentale e Clinica - Sezione Neuroscienze Cliniche, Universitá Politecnica delle Marche, Italy
| | - Laura Mazzanti
- Dipartimento di Scienze cliniche Specialistiche ed Odontostomatologiche (DISCO), Universitá Politecnica delle Marche, Italy
| | - Gianna Ferretti
- Dipartimento di Scienze cliniche Specialistiche ed Odontostomatologiche (DISCO), Universitá Politecnica delle Marche, Italy
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Plasma PAF-AH (PLA2G7): Biochemical Properties, Association with LDLs and HDLs, and Regulation of Expression. Enzymes 2015; 38:71-93. [PMID: 26612648 DOI: 10.1016/bs.enz.2015.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
This chapter is focused on the plasma form of PAF-acetylhydrolase (PAF-AH), a lipoprotein-bound, calcium-independent phospholipase A2 activity also referred to as lipoprotein-associated phospholipase A2 and PLA2G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress. Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. Several new mechanisms of regulation have been identified in recent years, including effects mediated by PPARs, VEGFR, and the state of cellular differentiation. Moreover, I discuss recent studies describing significant variations in the structure and regulation of PAF-AH from diverse species, which is likely to have important implications for the function of this enzyme in vivo.
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Affiliation(s)
- Diana M Stafforini
- Department of Internal Medicine University of Utah, Salt Lake City, UT 84112 Huntsman Cancer Institute, University of Utah, Salt Lake City, UT 84112
| | - Guy A Zimmerman
- Department of Internal Medicine University of Utah, Salt Lake City, UT 84112
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Chakraborti S, Alam MN, Chaudhury A, Sarkar J, Pramanik A, Asrafuzzaman S, Das SK, Ghosh SN, Chakraborti T. Pathophysiological Aspects of Lipoprotein-Associated Phospholipase A2: A Brief Overview. PHOSPHOLIPASES IN HEALTH AND DISEASE 2014:115-133. [DOI: 10.1007/978-1-4939-0464-8_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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Tellis CC, Moutzouri E, Elisaf M, Wolfert RL, Tselepis AD. The elevation of apoB in hypercholesterolemic patients is primarily attributed to the relative increase of apoB/Lp-PLA₂. J Lipid Res 2013; 54:3394-402. [PMID: 24092915 DOI: 10.1194/jlr.m041806] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is a risk factor of cardiovascular disease. Plasma Lp-PLA₂ is mainly associated with apolipoprotein (apo)B-containing lipoproteins, primarily with low density lipoproteins (LDLs). Importantly, only a proportion of circulating lipoproteins contain Lp-PLA₂. We determined the plasma levels of Lp-PLA₂-bound apoB (apoB/Lp-PLA₂) in patients with primary hypercholesterolemia. The effect of simvastatin therapy was also addressed. The plasma apoB/Lp-PLA₂ concentration in 50 normolipidemic controls and 53 patients with primary hypercholesterolemia at baseline and at 3 months posttreatment with simvastatin (40 mg/day) was determined by an enzyme-linked immunosorbent assay. The concentration of the apoB-containing lipoproteins that do not bind Lp-PLA₂ [apoB/Lp-PLA₂⁻] was calculated by subtracting the apoB/Lp-PLA₂ from total apoB. The apoB/Lp-PLA₂ levels were 3.6-fold higher, while apoB/Lp-PLA₂⁻ were 1.3-fold higher in patients compared with controls. After 3 months of simvastatin treatment apoB/Lp-PLA₂ and apoB/Lp-PLA₂⁻ levels were reduced by 52% and 33%, respectively. The elevation in apoB-containing lipoproteins in hypercholesterolemic patients is mainly attributed to the relative increase in the proatherogenic apoB/Lp-PLA₂, while simvastatin reduces these particles to a higher extent compared with apoB/Lp-PLA₂⁻. Considering that Lp-PLA₂ is proatherogenic, the predominance of apoB/Lp-PLA₂ particles in hypercholesterolemic patients may contribute to their higher atherogenicity and incidence of cardiovascular disease.
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Affiliation(s)
- Constantinos C Tellis
- Laboratory of Biochemistry, Department of Chemistry University of Ioannina, Ioannina, Greece
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9
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Arai K, Orsoni A, Mallat Z, Tedgui A, Witztum JL, Bruckert E, Tselepis AD, Chapman MJ, Tsimikas S. Acute impact of apheresis on oxidized phospholipids in patients with familial hypercholesterolemia. J Lipid Res 2012; 53:1670-8. [PMID: 22628616 DOI: 10.1194/jlr.p027235] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We measured oxidized phospholipids (OxPL), lipoprotein (a) [Lp(a)], and lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) pre- and postapheresis in 18 patients with familial hypercholesterolemia (FH) and with low(∼10 mg/dl; range 10-11 mg/dl), intermediate (∼50 mg/dl; range 30-61 mg/dl), or high (>100 mg/dl; range 78-128 mg/dl) Lp(a) levels. By using enzymatic and immunoassays, the content of OxPL and Lp-PLA(2) mass and activity were quantitated in lipoprotein density fractions plated in microtiter wells, as well as directly on apoB-100, Lp(a), and apoA-I immunocaptured within each fraction (i.e., OxPL/apoB and Lp-PLA(2)/apoB). In whole fractions, OxPL was primarily detected in the Lp(a)-containing fractions, whereas Lp-PLA(2) was primarily detected in the small, dense LDL and light Lp(a) range. In lipoprotein capture assays, OxPL/apoB and OxPL/apo(a) increased proportionally with increasing Lp(a) levels. Lp-PLA(2)/apoB and Lp-PLA(2)/apoA-I levels were highest in the low Lp(a) group but decreased proportionally with increasing Lp(a) levels. Lp-PLA(2)/apo(a) was lowest in patients with low Lp(a) levels and increased proportionally with increasing Lp(a) levels. Apheresis significantly reduced levels of OxPL and Lp-PLA(2) on apoB and Lp(a) (50-75%), particularly in patients with intermediate and high Lp(a) levels. In contrast, apheresis increased Lp-PLA(2)-specific activity (activity/mass ratio) in buoyant LDL fractions. The impact of apheresis on Lp(a), OxPL, and Lp-PLA(2) provides insights into its therapeutic benefits beyond lowering apoB-containing lipoproteins.
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10
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Guo ZG, Li C, Zhong JK, Tu Y, Xie D. Laboratory investigation of dysfunctional HDL. Chem Phys Lipids 2011; 165:32-7. [PMID: 22064068 DOI: 10.1016/j.chemphyslip.2011.10.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2011] [Revised: 10/18/2011] [Accepted: 10/21/2011] [Indexed: 11/26/2022]
Abstract
High-density lipoprotein (HDL) particles are anti-atherosclerotic, by virtue of their functions in reverse cholesterol transportation, anti-inflammation and anti-oxidation. However, recent studies have cast doubt on the cardio-protective role of HDL. Structural modification and composition alteration of HDL due to chronic inflammation and acute phase responses may result in loss of normal biological function and even convert HDL into a pro-inflammatory and pro-oxidative agent. Therefore, the assessment of dysfunctional HDL has become a novel target to investigate the association between HDL and coronary artery disease risk. This review article summarizes the laboratory assessment of dysfunctional HDL.
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Affiliation(s)
- Zhi Gang Guo
- Division of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, Guangdong, PR China.
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Holzer M, Birner-Gruenberger R, Stojakovic T, El-Gamal D, Binder V, Wadsack C, Heinemann A, Marsche G. Uremia alters HDL composition and function. J Am Soc Nephrol 2011; 22:1631-41. [PMID: 21804091 DOI: 10.1681/asn.2010111144] [Citation(s) in RCA: 208] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Functional impairment of HDL may contribute to the excess cardiovascular mortality experienced by patients with renal disease, but the effect of advanced renal disease on the composition and function of HDL is not well understood. Here, we used mass spectrometry and biochemical analyses to study alterations in the proteome and lipid composition of HDL isolated from patients on maintenance hemodialysis. We identified a significant increase in the amount of acute phase protein serum amyloid A1, albumin, lipoprotein-associated phospholipase A2, and apoC-III composing uremic HDL. Furthermore, uremic HDL contained reduced phospholipid and increased triglyceride and lysophospholipid. With regard to function, these changes impaired the ability of uremic HDL to promote cholesterol efflux from macrophages. In summary, the altered composition of HDL in renal disease seems to inhibit its cardioprotective properties. Assessing HDL composition and function in renal disease may help identify patients at increased risk for cardiovascular disease.
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Affiliation(s)
- Michael Holzer
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
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12
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Srinivasan P, Bahnson BJ. Molecular Model of Plasma PAF Acetylhydrolase-Lipoprotein Association: Insights from the Structure. Pharmaceuticals (Basel) 2010; 3:541-557. [PMID: 27713267 PMCID: PMC4033968 DOI: 10.3390/ph3030541] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2010] [Revised: 02/07/2010] [Accepted: 03/05/2010] [Indexed: 11/18/2022] Open
Abstract
Plasma platelet-activating factor acetylhydrolase (PAF-AH), also called lipoprotein-associated phospholipase A2 (Lp-PLA2), is a group VIIA PLA2 enzyme that catalyzes the hydrolysis of PAF and certain oxidized phospholipids. Although the role of PAF-AH as a pro- or anti-atherosclerotic enzyme is highly debated, several studies have shown it to be an independent marker of cardiovascular diseases. In humans the majority of plasma PAF-AH is bound to LDL and a smaller portion to HDL; the majority of the enzyme being associated with small dense LDL and VHDL-1 subclasses. Several studies suggest that the anti- or pro-atherosclerotic tendency of PAF-AH might be dependent on the type of lipoprotein it is associated with. Amino acid residues in PAF-AH necessary for binding to LDL and HDL have been identified. However our understanding of the interaction of PAF-AH with LDL and HDL is still incomplete. In this review we present an overview of what is already known about the interaction of PAF-AH with lipoprotein particles, and we pose questions that are yet to be answered. The recently solved crystal structure of PAF-AH, along with functional work done by others is used as a guide to develop a model of interaction of PAF-AH with lipoprotein particles.
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Affiliation(s)
| | - Brian J Bahnson
- Department of Chemistry & Biochemistry, University of Delaware, Newark, DE, 19716, USA.
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De Keyzer D, Karabina SA, Wei W, Geeraert B, Stengel D, Marsillach J, Camps J, Holvoet P, Ninio E. Increased PAFAH and Oxidized Lipids Are Associated With Inflammation and Atherosclerosis in Hypercholesterolemic Pigs. Arterioscler Thromb Vasc Biol 2009; 29:2041-6. [DOI: 10.1161/atvbaha.109.196592] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Objective—
To study the association of PAF-acetyl hydrolase (PAFAH) activity with inflammation, oxidative stress, and atherosclerosis in hypercholesterolemic swine.
Methods and Results—
Cholesterol-rich diet feeding of miniature pigs was associated with an increase in PAFAH activity and an increase of the PAFAH to PON1 ratio.
PLA2G7
RNA (coding for PAFAH) expression was increased in blood monocytes and plaque macrophages. Increased PAFAH activity was associated with higher plasma lysophosphatidylcholine and correlated with oxidized LDL. In THP1 monocytes and macrophages and in human blood-derived macrophages, oxidized LDL induced
PLA2G7
RNA expression. Atherogenic diet feeding induced the accumulation of macrophages and oxidized LDL in the arterial wall leading to atherosclerosis. PAFAH activity correlated positively with plaque size and
TNFalpha
expression in plaque macrophages.
Conclusions—
We demonstrated that an increase in PAFAH activity was associated with increased levels of lysophosphatidylcholine, oxidized LDL, and inflammation, resulting in accelerated atherosclerosis in hypercholesterolemic minipigs. The significant correlation between
PLA2G7
RNA expression in plaque macrophages and plasma PAFAH activity suggests that the latter is a consequence, rather than a cause of macrophage accumulation. Our cell experiments suggest that oxidized LDL can induce PAFAH, resulting in accumulation of lysophosphatidylcholine that increases the inflammatory action of oxidized LDL.
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Affiliation(s)
- Dieuwke De Keyzer
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Sonia-Athina Karabina
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Wenhzong Wei
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Benjamine Geeraert
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Dominique Stengel
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Judit Marsillach
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Jordi Camps
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Paul Holvoet
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
| | - Ewa Ninio
- From the Atherosclerosis and Metabolism Unit, Department of Cardiovascular Diseases (D.DK., B.G., P.H.), Katholieke Universiteit Leuven, Belgium; INSERM UMRS937 (S.A.K., W.W., D.S., E.N.), Université Pierre et Marie Curie UPMC-Paris 6 and Faculté de Médecine Pierre et Marie Curie, Paris, France; and Centre de Recerca Biomèdica (J.M., J.C.), Hospital Universitari de Sant Joan, Catalunya, Spain. Current affiliation for W.W.: Department of Biochemistry, University of Nebraska, Lincoln
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Proudfoot JM, Barden AE, Loke WM, Croft KD, Puddey IB, Mori TA. HDL is the major lipoprotein carrier of plasma F2-isoprostanes. J Lipid Res 2008; 50:716-22. [PMID: 19050315 DOI: 10.1194/jlr.m800607-jlr200] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Enhanced oxidative stress is implicated in the development of atherosclerosis in humans and animal models. F(2)-isoprostanes are formed in vivo via free radical peroxidation of arachidonic acid, and their quantification has allowed assessment of oxidative stress in vivo. F(2)-isoprostanes associate with lipids, although their distribution in human plasma lipoproteins is unknown. Our aim was to determine the distribution and levels of F(2)-isoprostanes in lipoproteins isolated from human plasma by ultracentrifugation and fast protein liquid chromatography (FPLC). F(2)-isoprostanes were significantly higher in HDL compared with LDL or VLDL after isolation by ultracentrifugation or FPLC. Furthermore, HDL3 particles contained elevated levels of F(2)-isoprostanes compared with HDL2. Platelet activating factor acetylhydrolase (PAF-AH), which hydrolyses esterified F(2)-isoprostanes from phospholipids, was predominantly associated with LDL. Reduced F(2)-isoprostanes in LDL may be related to higher PAF-AH activity in LDL. Paraoxonase 1 (PON-1) activity was associated with HDL2 and may be a contributing factor to the lower F(2)-isoprostanes in HDL2 compared with HDL3. Further studies are required to establish the implications of these findings on HDL function.
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Affiliation(s)
- Julie M Proudfoot
- School of Medicine and Pharmacology, University of Western Australia, Royal Perth Hospital, Perth WA 6847, Australia
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15
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Stafforini DM. Biology of platelet-activating factor acetylhydrolase (PAF-AH, lipoprotein associated phospholipase A2). Cardiovasc Drugs Ther 2008; 23:73-83. [PMID: 18949548 DOI: 10.1007/s10557-008-6133-8] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2008] [Accepted: 08/06/2008] [Indexed: 12/26/2022]
Abstract
INTRODUCTION This article is focused on platelet-activating factor acetylhydrolase (PAF-AH), a lipoprotein bound, calcium-independent phospholipase A(2) activity also referred to as lipoprotein-associated phospholipase A(2) or PLA(2)G7. PAF-AH catalyzes the removal of the acyl group at the sn-2 position of PAF and truncated phospholipids generated in settings of inflammation and oxidant stress. DISCUSSION Here, I discuss current knowledge related to the structural features of this enzyme, including the molecular basis for association with lipoproteins and susceptibility to oxidative inactivation. The circulating form of PAF-AH is constitutively active and its expression is upregulated by mediators of inflammation at the transcriptional level. This mechanism is likely responsible for the observed up-regulation of PAF-AH during atherosclerosis and suggests that increased expression of this enzyme is a physiological response to inflammatory stimuli. Administration of recombinant forms of PAF-AH attenuate inflammation in a variety of experimental models. Conversely, genetic deficiency of PAF-AH in defined human populations increases the severity of atherosclerosis and other syndromes. Recent advances pointing to an interplay among oxidized phospholipid substrates, Lp(a), and PAF-AH could hold the key to a number of unanswered questions.
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Affiliation(s)
- Diana M Stafforini
- Huntsman Cancer Institute and Department of Internal Medicine, University of Utah, 2000 Circle of Hope, Suite 3364, Salt Lake City, UT 84112-5550, USA.
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16
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Zhang B, Uehara Y, Hida S, Miura SI, Rainwater DL, Segawa M, Kumagai K, Rye KA, Saku K. Effects of reconstituted HDL on charge-based LDL subfractions as characterized by capillary isotachophoresis. J Lipid Res 2007; 48:1175-89. [PMID: 17327623 DOI: 10.1194/jlr.m600227-jlr200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Modified LDL in human plasma including small, dense LDL (sdLDL) and oxidized LDL carries a more negative charge than unmodified LDL and is atherogenic. We examined the effects of apolipoprotein A-I (apoA-I)/POPC discs on charge-based LDL subfractions as determined by capillary isotachophoresis (cITP). Three normal healthy subjects and seven patients with metabolic disorders were included in the study. LDL in human plasma was separated into two major subfractions, fast- and slow-migrating LDL (fLDL and sLDL), by cITP. Normal LDL was characterized by low fLDL, and mildly oxidized LDL in vitro and mildly modified LDL in human plasma were characterized by increased fLDL. Moderately oxidized LDL in vitro and moderately modified LDL in a patient with hypertriglyceridemia and HDL deficiency were characterized by both increased fLDL and a new LDL subfraction with a faster mobility than fLDL [very-fast-migrating LDL as determined by cITP (vfLDL)]. cITP LDL subfractions with faster electrophoretic mobility (fLDL vs. sLDL, vfLDL vs. fLDL) were associated with an increased content of sdLDL. Incubation of a plasma fraction with d>1.019 g/ml (depleted of triglyceride-rich lipoproteins) in the presence of apoA-I/POPC discs at 37 degrees C greatly decreased vfLDL and fLDL but increased sLDL. Incubation of whole plasma from patients with an altered distribution of cITP LDL subfractions in the presence of apoA-I/POPC discs also greatly decreased fLDL but increased sLDL. ApoA-I/POPC discs decreased the cITP fLDL level, the free cholesterol concentration, and platelet-activating factor acetylhydrolase activity in the sdLDL subclasses (d=1.040-1.063 g/ml) and increased the size of LDL. ApoA-I/POPC discs reduced charge-modified LDL in human plasma by remodeling cITP fLDL into sLDL subfractions.
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Affiliation(s)
- Bo Zhang
- Department of Cardiology, Fukuoka University School of Medicine, Fukuoka, Japan.
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17
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Cho KH, Han JM, Jeong TS, Kim HC, Lee JH, Lee JH, Lee KT. Anti-Atherosclerotic Effect of a New Synthetic Functional Oil Containing Mono- and Diacylglycerol from Corn Oil. ANNALS OF NUTRITION AND METABOLISM 2006; 50:467-75. [PMID: 16931881 DOI: 10.1159/000095353] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2005] [Accepted: 05/22/2006] [Indexed: 11/19/2022]
Abstract
Synthetic oil containing diacylglycerol and monoacylglycerol, called 'functional oil' (FO), was newly produced and evaluated for its putative anti-atherosclerotic potential by in vitro assays and in vivo test using hypercholesterolemic mice (C57BL/6). The FO revealed good inhibitory activities against both liver acyl-CoA:cholesterol acyltransferase and serum lipoprotein-associated phospholipase A2. The FO showed enhanced activities on lipoprotein interaction such as HDL particle rearrangement to produce different sizes of HDL species. In control mice, hypercholesterolemia was induced by consumption of high-cholesterol, high-fat (HCHF) diet that contained 1.25% cholesterol/15% fat/0.5% Na-cholate with or without 5% of corn oil. In experimental mice, 5% of the FO + HCHF diet was fed during the same period. After the 4-week administration of the diet, serum total cholesterol concentration of the FO-fed group decreased by 38 or 20% when compared to the HCHF diet control group or corn oil (99.9% of triacylglycerol) diet group, respectively. The percentage of HDL cholesterol to total cholesterol was 36% of HDL cholesterol in the FO-fed group, while the HCHF control group and corn oil-fed group showed 21 and 25%, respectively. These results indicate that the FO possesses a blood cholesterol-lowering effect in mouse model and inhibition effects against the atherogenic enzymes.
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Affiliation(s)
- Kyung-Hyun Cho
- School of Biotechnology, Yeungnam University, Gyeongsan, South Korea
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18
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Rufail ML, Schenkein HA, Barbour SE, Tew JG, van Antwerpen R. Altered lipoprotein subclass distribution and PAF-AH activity in subjects with generalized aggressive periodontitis. J Lipid Res 2005; 46:2752-60. [PMID: 16179738 DOI: 10.1194/jlr.m500389-jlr200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study, we examined whether the documented increase of plasma triglycerides in patients with generalized aggressive periodontitis (GAgP) is associated with changes in lipoprotein subclass distribution and/or LDL-associated platelet-activating factor acetylhydrolase (PAF-AH) activity. Lipoprotein subclasses were analyzed in whole plasma samples using nuclear magnetic resonance methods. Compared with subjects without periodontitis (NP subjects; n = 12), GAgP subjects (n = 12) had higher plasma levels of large, medium, and small VLDL (35.0 +/- 6.7 vs. 63.1 +/- 9.6 nmol/l; P = 0.025), higher levels of intermediate density lipoprotein (24.8 +/- 11.6 vs. 87.2 +/- 16.6 nmol/l; P = 0.006), lower levels of large LDL (448.3 +/- 48.5 vs. 315.8 +/- 59.4 nmol/l; P = 0.098), and higher levels of small LDL (488.2 +/- 104.2 vs. 946.7 +/- 151.6 nmol/l; P = 0.021). The average size of LDL from NP and GAgP subjects was 21.4 +/- 0.2 and 20.6 +/- 0.3 nm, respectively (P = 0.031). Compared with NP subjects, GAgP subjects had a greater number of circulating LDL particles (961.3 +/- 105.3 vs. 1,349.0 +/- 133.2 nmol/l; P = 0.032). Differences in the plasma levels of large, medium, and small HDL were not statistically significant. NP and GAgP subjects had similar plasma levels of total LDL-associated PAF-AH activity; however, LDL of GAgP subjects contained less PAF-AH activity per microgram of LDL protein (1,458.0 +/- 171.0 and 865.2 +/- 134 pmol/min/microg; P = 0.014). These results indicate that, in general, GAgP subjects have a more atherogenic lipoprotein profile and lower LDL-associated PAF-AH activity than NP subjects. These differences may help explain the increased risk of GAgP subjects for cardiovascular disease.
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Affiliation(s)
- Miguel L Rufail
- Department of Biochemistry, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
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Gazi I, Lourida ES, Filippatos T, Tsimihodimos V, Elisaf M, Tselepis AD. Lipoprotein-associated phospholipase A2 activity is a marker of small, dense LDL particles in human plasma. Clin Chem 2005; 51:2264-73. [PMID: 16223884 DOI: 10.1373/clinchem.2005.058404] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Recent clinical studies showed that lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a predictor for incident atherosclerotic disease. We have previously shown that among the LDL subfractions, Lp-PLA(2) activity is preferentially associated with the atherogenic small, dense (sdLDL) particles in vitro. We investigated whether Lp-PLA(2) could be a marker of sdLDL in human plasma. METHODS One hundred and seventy-six individuals participated in the study. LDL subclass analysis was performed by polyacrylamide gel electrophoresis. Lp-PLA(2) activity and mass were determined in total plasma and in apolipoprotein B-depleted plasma (HDL-Lp-PLA(2)). Non-HDL-Lp-PLA(2) activity and mass were calculated by subtracting the HDL-Lp-PLA(2) from total plasma Lp-PLA(2). RESULTS On the basis of the LDL subclass analysis, participants were categorized into phenotype A and non-A (total cholesterol mass of the sdLDL subfractions < or =0.155 and >0.155 mmol/L, respectively). Unlike total plasma Lp-PLA(2) mass, total plasma Lp-PLA(2) activity and non-HDL-Lp-PLA(2) activity and mass were significantly higher in persons with phenotype non-A compared with persons with phenotype A, whereas HDL-Lp-PLA(2) activity and mass were lower in persons with phenotype non-A compared with phenotype A. Total plasma activity and non-HDL-Lp-PLA(2) activity and mass, but not Lp-PLA(2) mass, were correlated with sdLDL-cholesterol mass, proportion, and mean LDL particle size. In multiple regression analysis, total plasma and non-HDL-Lp-PLA(2) activities were the second best predictors of the presence of sdLDL particles in human plasma after serum triglyceride concentrations. At serum triglyceride concentrations >1.356 mmol/L, total plasma and non-HDL-Lp-PLA(2) activity added significantly to the prediction of the presence of sdLDL in plasma. CONCLUSIONS Lp-PLA(2) activity, but not the enzyme mass, is a marker of sdLDL in human plasma.
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Affiliation(s)
- Irene Gazi
- Department of Internal Medicine, Medical School, University of Ioannina, Greece
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20
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Kontush A, Chantepie S, Chapman MJ. Small, dense HDL particles exert potent protection of atherogenic LDL against oxidative stress. Arterioscler Thromb Vasc Biol 2003; 23:1881-8. [PMID: 12920049 DOI: 10.1161/01.atv.0000091338.93223.e8] [Citation(s) in RCA: 315] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The relationship of the structural and functional heterogeneity of HDL particles to protection of LDL against oxidative stress is indeterminate. METHODS AND RESULTS HDL subfractions of defined physicochemical properties were isolated by density gradient ultracentrifugation from normolipidemic human serum (n=8), and their capacity to protect LDL from oxidation was evaluated. Under mild oxidative stress induced by AAPH or Cu(II), HDL subfractions (at equal cholesterol or protein concentration or equal particle number) significantly decreased LDL oxidation rate (-20% to -85%) in the propagation phase (234 nm), which was prolonged by up to 82% with decreased maximal diene formation. Antioxidative activity of HDL subfractions increased with increment in density, as follows: HDL2b<HDL2a<HDL3a<HDL3b<HDL3c (confirmed by thiobarbituric acid-reactive substance content and LDL electrophoretic mobility). Concordantly, antioxidative activity of small HDL prepared by FPLC was significantly higher (+56%) than that of large HDL. Antioxidative action of HDL subfractions was primarily associated with inactivation of LDL lipid hydroperoxides. The potent protective activity of small HDL could not be accounted for exclusively by enzymatic activities (PON1, platelet-activating factor acetylhydrolase, and lecithin-cholesterol acyltransferase). CONCLUSIONS Small, dense HDL exhibit potent antioxidant activity, which may arise from synergy in inactivation of oxidized LDL lipids by enzymatic and nonenzymatic mechanisms, in part reflecting distinct intrinsic physicochemical properties.
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Affiliation(s)
- Anatol Kontush
- Dyslipoproteinemia and Atherosclerosis Research Unit (U.551), National Institute for Health and Medical Research (INSERM), Hôpital de la Pitié, Paris, France.
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21
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Benítez S, Sánchez-Quesada JL, Ribas V, Jorba O, Blanco-Vaca F, González-Sastre F, Ordóñez-Llanos J. Platelet-activating factor acetylhydrolase is mainly associated with electronegative low-density lipoprotein subfraction. Circulation 2003; 108:92-6. [PMID: 12821559 DOI: 10.1161/01.cir.0000072791.40232.8f] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Electronegative LDL [LDL(-)], a modified subfraction of LDL present in plasma, induces the release of interleukin-8 and monocyte chemotactic protein-1 from cultured endothelial cells. METHODS AND RESULTS We demonstrate that platelet-activating factor acetylhydrolase (PAF-AH) is mainly associated with LDL(-). LDL(-) had 5-fold higher PAF-AH activity than the nonelectronegative LDL subfraction [LDL(+)] in both normolipemic and familial hypercholesterolemic subjects. Western blot analysis after SDS-PAGE confirmed these results, because a single band of 44 kDa corresponding to PAF-AH appeared in LDL(-) but not in LDL(+). Nondenaturing polyacrylamide gradient gel electrophoresis demonstrated that PAF-AH was bound to LDL(-) regardless of LDL size. In accordance with the above findings, nonesterified fatty acids, a cleavage product of PAF-AH, were increased in LDL(-) compared with LDL(+). CONCLUSIONS The high PAF-AH activity observed in LDL(-) could be related to the proinflammatory activity of these lipoproteins toward cultured endothelial cells.
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Affiliation(s)
- Sonia Benítez
- Servei de Bioquímica and Institut de Recerca, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
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22
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Abuzeid AM, Hawe E, Humphries SE, Talmud PJ. Association between the Ala379Val variant of the lipoprotein associated phospholipase A2 and risk of myocardial infarction in the north and south of Europe. Atherosclerosis 2003; 168:283-8. [PMID: 12801611 DOI: 10.1016/s0021-9150(03)00086-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) has been identified as a coronary heart disease (CHD) risk predictor. Both its anti-inflammatory role by hydrolysing platelet activating factor, and pro-inflammatory generation of atherogenic mediators may influence CHD risk. We investigated the association of the activity-reducing A379V variant with risk of myocardial infarction (MI) in a large European case-control study, which compared 527 post-MI men with 566 age-matched controls from north and south Europe. Overall, the frequency of the V379 allele was 0.24 (95%CI 0.21-0.26), with no evidence for differences between centres. Homozygosity for the V379 allele was associated with lower risk of MI, (Odds Ratio (OR) 0.56, 95%CI 0.32-0.98), maintained after adjustment for lifestyle factors and levels of inflammatory risk factors (C-reactive protein, fibrinogen, IL-6) (OR 0.46, 0.22-0.93). There was no evidence of heterogeneity of effect between the centres in the north and south of Europe (P-value for interaction=0.80). Since homozygosity for V379 occurs in only 5-6% of subjects, this genotype is not a major determinant of population genetic risk of CHD, but the association of this genotype with low levels of Lp-PLA(2), strongly support the pro-inflammatory causative, and not consequential, role of Lp-PLA(2) in CHD.
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Affiliation(s)
- A M Abuzeid
- Division of Cardiovascular Genetics, Department of Medicine, British Heart Foundation Laboratories, Rayne Building, Royal Free and University College Medical School, 5 University St, London WC1E 6JJ, UK
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23
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Tsimihodimos V, Kakafika A, Tambaki AP, Bairaktari E, Chapman MJ, Elisaf M, Tselepis AD. Fenofibrate induces HDL-associated PAF-AH but attenuates enzyme activity associated with apoB-containing lipoproteins. J Lipid Res 2003; 44:927-34. [PMID: 12611907 DOI: 10.1194/jlr.m200452-jlr200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human plasma platelet-activating factor acetylhydrolase (PAF-AH) is an enzyme associated mainly with the apolipoprotein B (apoB)-containing lipoproteins and primarily with LDL. A small proportion of enzymatic activity is also associated with HDL. Plasma paraoxonase 1 (PON1) is an esterase exclusively associated with HDL. The effect of fenofibrate on PAF-AH and PON1 activities in patients with dyslipidemias of Types IIA, IIB, and IV were studied. Fenofibrate reduced plasma PAF-AH activity in all patient groups. In Type IIA patients, this reduction was mainly due to a fall in enzyme activity associated with the dense LDL subspecies, whereas in Type IIB and Type IV patients, it was due to the decrease in PAF-AH activity associated with both the VLDL+IDL and dense LDL subspecies. Drug therapy in Type IIB and Type IV patients significantly increased the HDL-associated PAF-AH activity due to the increase in enzyme activity associated with the HDL-3c subfraction. Fenofibrate did not affect serum PON1 activities toward paraoxon and phenylacetate in either patient group. The fenofibrate-induced elevation of HDL-associated PAF-AH activity in dyslipidemic patients of Type IIB and Type IV, as well as the reduction in enzyme activity associated with atherogenic apoB-containing lipoproteins in all patient groups, may represent a new and important antiatherogenic effect of this potent lipid-modulating agent.
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Tselepis AD, John Chapman M. Inflammation, bioactive lipids and atherosclerosis: potential roles of a lipoprotein-associated phospholipase A2, platelet activating factor-acetylhydrolase. ATHEROSCLEROSIS SUPP 2002; 3:57-68. [PMID: 12573364 DOI: 10.1016/s1567-5688(02)00045-4] [Citation(s) in RCA: 229] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
It is well established that inflammation is an integral feature of atherosclerosis and of the cardiovascular diseases which it underlies. Oxidative stress is also recognized as a key actor in atherogenesis, in which it is closely associated with the inflammatory response and bioactive lipid formation. Several bioactive lipids have been identified in the atherosclerotic plaque, including the potent inflammatory mediator platelet activating factor (PAF), PAF-like lipids, oxidised phospholipids (oxPL) and lysophosphatidylcholine (lyso-PC). Recent evidence has established a central role of two phospholipases (PL) in atherogenesis, the non-pancreatic Type II secretory phospholipase A(2) (sPLA(2)) and the lipoprotein-associated PLA(2)-alternatively termed as PAF-acetylhydrolase (PAF-AH). sPLA(2) is calcium-dependent and hydrolyses the sn-2 acyl group of glycerophospholipids of lipoproteins and cell membranes to produce lyso-PC and free fatty acids. It is also implicated in isoprostane production from oxPL. sPLA(2) is an acute phase reactant, which is upregulated by inflammatory cytokines and may represent a new independent risk factor for coronary heart disease. In contrast to sPLA(2), PAF-AH is calcium-independent and is specific for short acyl groups at the sn-2 position of the phospholipid substrate and with the exception of PAF, can equally hydrolyze oxPL to generate lyso-PC and oxidized fatty acids. Thus PAF-AH plays a key role in the degradation of proinflammatory oxPL and in the generation of lyso-PC and oxidized fatty acids. PAF-AH equally can also hydrolyze short-chain diacylglycerols, triacylglycerols, and acetylated alkanols, and displays a PLA(1) activity. Whereas sPLA(2) may represent a new independent risk factor for coronary artery disease, the potential relevance of PAF-AH to atherosclerosis remains the subject of debate, and recent results suggest that the potential role of the LDL-associated PAF-AH in atherogenesis may be distinct to that of the HDL-associated enzyme. This review is focused on the main structural and catalytic features of plasma PAF-AH, on the association of the enzyme with distinct lipoprotein particle subspecies, on its cellular sources, and finally on the potential significance of this lipoprotein-associated PLA(2) in cardiovascular disease.
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Tsimihodimos V, Karabina SAP, Tambaki AP, Bairaktari E, Miltiadous G, Goudevenos JA, Cariolou MA, Chapman MJ, Tselepis AD, Elisaf M. Altered distribution of platelet-activating factor-acetylhydrolase activity between LDL and HDL as a function of the severity of hypercholesterolemia. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)30167-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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26
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Carpenter KL, Dennis IF, Challis IR, Osborn DP, Macphee CH, Leake DS, Arends MJ, Mitchinson MJ. Inhibition of lipoprotein-associated phospholipase A2 diminishes the death-inducing effects of oxidised LDL on human monocyte-macrophages. FEBS Lett 2001; 505:357-63. [PMID: 11576528 DOI: 10.1016/s0014-5793(01)02840-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The death of macrophages contributes to atheroma formation. Oxidation renders low-density lipoprotein (LDL) cytotoxic to human monocyte-macrophages. Lipoprotein-associated phospholipase A2 (Lp-PLA2), also termed platelet-activating factor acetylhydrolase, hydrolyses oxidised phospholipids. Inhibition of Lp-PLA2 by diisopropyl fluorophosphate or Pefabloc (broad-spectrum serine esterase/protease inhibitors), or SB222657 (a specific inhibitor of Lp-PLA2) did not prevent LDL oxidation, but diminished the ensuing toxicity and apoptosis induction when the LDL was oxidised, and inhibited the rise in lysophosphatidylcholine levels that occurred in the inhibitors' absence. Hydrolysis products of oxidised phospholipids thus account for over a third of the cytotoxic and apoptosis-inducing effects of oxidised LDL on macrophages.
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Affiliation(s)
- K L Carpenter
- Department of Pathology, University of Cambridge, UK.
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27
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Bielicki JK, Knoff LJ, Tribble DL, Forte TM. Relative sensitivities of plasma lecithin:cholesterol acyltransferase, platelet-activating factor acetylhydrolase, and paraoxonase to in vitro gas-phase cigarette smoke exposure. Atherosclerosis 2001; 155:71-8. [PMID: 11223428 DOI: 10.1016/s0021-9150(00)00539-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In order to identify potential atherogenic properties of gas-phase cigarette smoke, we utilized an in vitro exposure model to determine whether the activities of several putative anti-atherogenic enzymes associated with plasma lipoproteins were compromised. Exposure of heparinized human plasma to gas-phase cigarette smoke produced a dose-dependent reduction in the activity of platelet-activating factor acetylhydrolase (PAF-AH). Reductions of nearly 50% in PAF-AH activity were observed following exposure to gas-phase smoke from four cigarettes over an 8-h period. During this time of exposure, lecithin:cholesterol acyltransferase (LCAT) was rendered almost completely inactive (>80%). In contrast, paraoxonase was totally unaffected by cigarette smoke. Supplementation of plasma with 1 mM reduced glutathione was found to protect both PAF-AH and LCAT from cigarette smoke, suggesting that cysteine modifications may have contributed to the inhibition of these two enzymes. To evaluate this possibility, we blocked the free cysteine residues of these enzymes with the reversible thiol-modifying reagent dithiobisnitrobenzoic acid (DTNB). Reversal of the DTNB-cysteine adducts following cigarette smoke exposures revealed that LCAT, but not PAF-AH, was protected. Moreover, high doses (1.0-10 mM) of acrolein and 4-hydroxynonenal, reactive aldehydic species associated with cigarette smoke, completely inhibited plasma LCAT activity, whereas PAF-AH was resistant to such exposures. Taken together, these results indicate a divergence regarding the underlying mechanism of PAF-AH and LCAT inhibition upon exposure to gas-phase cigarette smoke. While LCAT was sensitive to exposure to volatile aldehydic products involving, in part, cysteine and/or active site modifications, the enzyme PAF-AH exhibited an apparent resistance. The latter suggests that the active site of PAF-AH is in a microenvironment that lacks free cysteine residues and/or is shielded from volatile aldehydic combustion products. Based on these results, we propose that cigarette smoke may contribute to atherogenesis by inhibiting the activities of plasma PAF-AH and LCAT, but the nature of this inhibition differs for the enzymes.
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Affiliation(s)
- J K Bielicki
- Lawrence Berkeley National Laboratory, University of California at Berkeley, Donner Laboratory MS 1-213, Berkeley, CA 94720, USA.
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28
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Prescott SM, Zimmerman GA, Stafforini DM, McIntyre TM. Platelet-activating factor and related lipid mediators. Annu Rev Biochem 2001; 69:419-45. [PMID: 10966465 DOI: 10.1146/annurev.biochem.69.1.419] [Citation(s) in RCA: 550] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Platelet-activating factor (PAF) is a phospholipid with potent, diverse physiological actions, particularly as a mediator of inflammation. The synthesis, transport, and degradation of PAF are tightly regulated, and the biochemical basis for many of these processes has been elucidated in recent years. Many of the actions of PAF can be mimicked by structurally related phospholipids that are derived from nonenzymatic oxidation, because such compounds can bind to the PAF receptor. This process circumvents much of the biochemical control and presumably is regulated primarily by the rate of degradation, which is catalyzed by PAF acetylhydrolase. The isolation of cDNA clones encoding most of the key proteins involved in regulating PAF has allowed substantial recent progress and will facilitate studies to determine the structural basis for substrate specificity and the precise role of PAF in physiological events.
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Affiliation(s)
- S M Prescott
- The Huntsman Cancer Institute, University of Utah, Salt Lake City, Utah 84112, USA.
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29
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Affiliation(s)
- R H Eckel
- Department of Physiology and Biophysics, University of Colorado, Health Sciences Building, 4200 E Ninth Ave, Campus box B-151, Denver, CO 80262, USA
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30
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Abstract
Small, dense LDL particles have been linked to atherosclerosis, often in a cluster of risk factors and affecting approximately 20% of adults. Over the past year, studies confirmed that small dense LDL is an autosomal dominant trait, influenced mainly by hypertriglyceridaemia and obesity, insulin resistance and diabetes mellitus and some incompletely investigated genetic loci. Compositional and functional differences have been observed in small LDL. Evidence is emerging that lifestyle as well as pharmacological intervention can modulate LDL size, but there is no proof yet that this is of clinical benefit.
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Affiliation(s)
- A D Marais
- Lipid Laboratory, Cape Heart Centre and MRC Cape Heart Group, University of Cape Town Health Sciences Faculty, Anzio Road, Observatory 7925, South Africa.
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31
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Tjoelker LW, Stafforini DM. Platelet-activating factor acetylhydrolases in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1488:102-23. [PMID: 11080681 DOI: 10.1016/s1388-1981(00)00114-1] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The platelet-activating factor (PAF) acetylhydrolases catalyze hydrolysis of the sn-2 ester bond of PAF and related pro-inflammatory phospholipids and thus attenuate their bioactivity. One secreted (plasma) and four intracellular isozymes have been described. The intracellular isozymes are distinguished by differences in primary sequence, tissue localization, subunit composition, and substrate preferences. The most thoroughly characterized intracellular isoform, Ib, is a G-protein-like complex with two catalytic subunits (alpha1 and alpha2) and a regulatory beta subunit. The beta subunit is a product of the LIS1 gene, mutations of which cause Miller-Dieker lissencephaly. Isoform II is a single polypeptide that is homologous to the plasma PAF acetylhydrolase and has antioxidant activity in several systems. Plasma PAF acetylhydrolase is also a single polypeptide with a catalytic triad of amino acids that is characteristic of the alpha/beta hydrolases. Deficiency of this enzyme has been associated with a number of pathologies. The most common inactivating mutation, V279F, is found in >30% of randomly surveyed Japanese subjects (4% homozygous, 27% heterozygous). The prevalence of the mutant allele is significantly greater in patients with asthma, stroke, myocardial infarction, brain hemorrhage, and nonfamilial cardiomyopathy. Preclinical studies have demonstrated that recombinant plasma PAF acetylhydrolase can prevent or attenuate pathologic inflammation in a number of animal models. In addition, preliminary clinical results suggest that the recombinant enzyme may have pharmacologic potential in human inflammatory disease as well. These observations underscore the physiological importance of the PAF acetylhydrolases and point toward new approaches for controlling pathologic inflammation.
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32
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Francis GA. High density lipoprotein oxidation: in vitro susceptibility and potential in vivo consequences. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1483:217-35. [PMID: 10634938 DOI: 10.1016/s1388-1981(99)00181-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Elevated levels of plasma high density lipoprotein (HDL) are strongly predictive of protection against atherosclerotic vascular disease. HDL particles likely have several beneficial actions in vivo, including the initiation of reverse cholesterol transport. The apparent importance of oxidative modification of low density lipoprotein in atherogenesis raises the question of how oxidative modification of HDL might affect its cardioprotective actions. HDL is readily oxidized using numerous models of lipoprotein oxidation. In vitro evidence suggests oxidation might impair some protective actions, but actually enhance other mechanisms induced by HDL that prevent the accumulation of cholesterol in the artery wall. This article reviews the current literature concerning the relative oxidizability of HDL, the structural changes induced in HDL by oxidation in vitro, and the potential consequences of oxidative modification on the protective actions of HDL in vivo.
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Affiliation(s)
- G A Francis
- Lipid and Lipoprotein Research Group and Department of Medicine, University of Alberta, Edmonton, Alta., Canada.
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