High-density Lipoprotein Antioxidant Function Research Articles

Impaired HDL antioxidant and anti-inflammatory functions are linked to increased mortality in acute heart failure patients

AimsAcute heart failure (AHF) is typified by inflammatory and oxidative stress responses, which are associated with unfavorable patient outcomes. Given the anti-inflammatory and antioxidant properties of high-density lipoprotein (HDL), this study sought to examine the relationship between impaired HDL function and mortality in AHF patients. The complex interplay between various HDL-related biomarkers and clinical outcomes remains poorly understood. MethodsHDL subclass distribution was quantified by nuclear magnetic resonance spectroscopy. Lecithin–cholesterol acyltransferase (LCAT) activity, cholesterol ester transfer protein (CETP) activity, and paraoxonase (PON-1) activity were assessed using fluorometric assays. HDL-cholesterol efflux capacity (CEC) was assessed in a validated assay using [3H]-cholesterol-labeled J774 macrophages. ResultsAmong the study participants, 74 (23.5 %) out of 315 died within three months after hospitalization due to AHF. These patients exhibited lower activities of the anti-oxidant enzymes PON1 and LCAT, impaired CEC, and lower concentration of small HDL subclasses, which remained significant after accounting for potential confounding factors. Smaller HDL particles, particularly HDL3 and HDL4, exhibited a strong association with CEC, PON1 activity, and LCAT activity. ConclusionsIn patients with AHF, impaired HDL CEC, HDL antioxidant and anti-inflammatory function, and impaired HDL metabolism are associated with increased mortality. Assessment of HDL function and subclass distribution could provide valuable clinical information and help identify patients at high risk.

Oxidized high-density lipoprotein associates with atrial fibrillation

BackgroundAtrial fibrillation (AF) is the most common heart arrhythmia and considered to be a progressive chronic disease associated with increased morbidity and mortality. Recent data suggest a link between inflammation, oxidative stress, and AF, although the underlying mechanisms are not fully understood. Because oxidized lipoproteins cause structural damage and electrophysiologic changes in cardiomyocytes, it is feasible that the transformation of atheroprotective high-density lipoprotein (HDL) into dysfunctional HDL contributes to the development of AF. ObjectiveThe purpose of this study was to determine whether a reduced antioxidant function of HDL is associated with the presence of AF. MethodsIn this multicenter cross-sectional cohort study, we assessed HDL function in sera of 1206 participants. Patients were divided into groups according to the presence of AF (n = 233) or no AF (n = 973). A validated cell-free biochemical assay was used to determine reduced HDL antioxidant function as assessed by increased normalized HDL lipid peroxide content (nHDLox). ResultsParticipants with AF had a 9% higher mean relative nHDLox compared to persons without AF (P = .025). nHDLox was strongly associated with AF in all models of logistic regression, including the analysis adjusted for age, sex, and risk factors for AF (all P ≤.01). ConclusionReduced antioxidant HDL function is associated with the presence of AF, which supports growing evidence that impaired lipoprotein function is linked to electrophysiological changes in cardiomyocytes. nHDLox is one of several contributors to the initiation and perpetuation of AF.

The association between high-density lipoproteins and periodontitis.

Periodontitis is one of the most typical chronic dental diseases. This inflammatory disease can change various functions of immune cells and impair lipid metabolism through proinflammatory cytokines. High-Density Lipoprotein (HDL) is considered protective of the cardiovascular system. It has anti-thrombotic and anti-inflammatory effects. In this article, we have reviewed the association between periodontitis and HDL. Various studies have demonstrated a reverse relationship between inflammatory cytokines and HDL. HDL contains antioxidative enzymes and proteins, whereas periopathogens impair HDL's antioxidant function. The presence of periodontal bacteria is associated with a low HDL level in patients with periodontitis. Genetic variants in the interleukin-6 (IL)-6 gene and cytochrome (CYP)1A1 rs1048943 gene polymorphism are associated with HDL levels and periodontal status. Studies showed that HDL levels improve after treatment for periodontitis. On the one hand, periodontal pathogenic bacteria and their metabolites and pro-inflammatory cytokines from periodontal infection can result in various disorders of lipid metabolism and lipid peroxidation. On the other hand, hyperlipidemia and lipid peroxidation stimulate proinflammatory cytokines, resulting in oxidative stress and delayed wound healing, making individuals susceptible to periodontitis.

Dysfunctional antioxidant capacity of high-density lipoprotein in rheumatoid arthritis.

High-density lipoprotein (HDL) presents atheroprotective functions not readily reflected by plasma HDL-cholesterol levels. The aim of this study was to investigate HDL antioxidant function in patients with rheumatoid arthritis (RA). This pilot and cross-sectional study included 50 RA patients and 50 controls matched by age, gender, cardiovascular risk factors and drug therapy. The antioxidant capacity of HDL was assessed by the total radical-trapping antioxidative potential test (TRAP-assay) and the susceptibility of low-density lipoprotein (LDL) to oxidation by the Conjugated Dienes Assay (Dmax ). A carotid ultrasound was performed in all participants to detect subclinical atherosclerosis. High-density lipoprotein from RA patients showed lower antioxidant capacity than those from controls [oxidized-LDL%: 35.8 (27-42) vs. 24.4 (20-32), p < .001] when analysed with the TRAP-assay. In addition, the time to achieve 50% of maximal LDL oxidation (Lag-time) was shorter in RA-patients than in matched controls [57.2 (42-71) vs. 69.5 (55-75) minutes, (p = .003)]. RA patients showed a higher atherosclerotic burden than controls. The pro-oxidant pattern in RA was irrespective of the presence of carotid atherosclerosis. On the contrary, there was a positive correlation between inflammatory parameters (erythrocyte sedimentation rate, ultrasensitive C-reactive protein and fibrinogen) and the loss of HDL-anti-oxidant capacity measured by the TRAP-assay (rho = .211, p = .035; rho = .231, p = .021 and rho = .206, p = .041, respectively). Furthermore, the glucocorticoid dose at recruitment was negatively associated with the Lag-time in RA patients (rho = -.387, p = .026). Rheumatoid arthritis patients present reduced HDL antioxidant capacity and a lower resistance of LDL particles to oxidation, mainly related to the degree of inflammation.

Probucol will become a new model for treating cerebral infarction with a high risk of hemorrhage: A narrative review.

Lipid-lowering agents are relevant in stroke prevention. Probucol (PU) is an antioxidative and lipid-lowering drug that has been used to treat atherosclerotic cardiovascular diseases and xanthomas. The drug penetrates the core of low-density lipoprotein cholesterol (LDL-C) particles, enhancing the activity of plasma cholesterol l ester transfer protein (CETP) and strengthening the liver scavenger receptor type I, resulting in reducing LDL-C; by increasing the activity of paraoxonase 1, upregulating the antioxidant function of high-density lipoprotein (HDL), and it decreases the serum HDL-cholesterol (HDL-C) level. This drug has been retired from the Western markets for lowering HDL-C levels and Q-interval prolongation. The latter side effect has been rarely reported and may be transient. Recent clinical evidence supports the effectiveness of PU in preventing cardiovascular events and in reducing mortality, irrespective of the reduction of HDL-C. Based on basic research and clinical studies, it appears that PU might be a valuable alternative when statins are ineffective or contraindicated, in patients at high risk of recurrence of cerebral ischemia and hemorrhage.

High levels of oxidized fatty acids in HDL impair the antioxidant function of HDL in patients with diabetes.

Previous studies demonstrate that the antioxidant functions of high-density lipoprotein (HDL) are impaired in diabetic patients. The composition of HDL plays an important role in maintaining the normal functionality of HDL. In this study, we compared the levels of oxidized fatty acids in HDL from diabetic subjects and non-diabetic healthy controls, aiming to investigate the role of oxidized fatty acids in the antioxidant property of HDL. HDL was isolated from healthy subjects (n=6) and patients with diabetes (n=6, hemoglobin A1c ≥ 9%, fasting glucose ≥ 7 mmol/L) using a dextran sulfate precipitation method. Cholesterol efflux capacity mediated by HDL was measured on THP-1 derived macrophages. The antioxidant capacity of HDL was evaluated with dichlorofluorescein-based cellular assay in human aortic endothelial cells. Oxidized fatty acids in HDL were determined by liquid chromatography-tandem mass spectrometry. The correlations between the levels of oxidized fatty acids in HDL and the endothelial oxidant index in cells treated with HDLs were analyzed through Pearson's correlation analyses, and the effects of oxidized fatty acids on the antioxidant function of HDL were verified in vitro. The cholesterol efflux capacity of HDL and the circulating HDL-cholesterol were similar in diabetic patients and healthy controls, whereas the antioxidant capacity of HDL was significantly decreased in diabetic patients. There were higher levels of oxidized fatty acids in HDL isolated from diabetic patients, which were strongly positively correlated with the oxidant index of cells treated with HDLs. The addition of a mixture of oxidized fatty acids significantly disturbed the antioxidant activity of HDL from healthy controls, while the apolipoprotein A-I mimetic peptide D-4F could restore the antioxidant function of HDL from diabetic patients. HDL from diabetic patients displayed substantially impaired antioxidant activity compared to HDL from healthy subjects, which is highly correlated with the increased oxidized fatty acids levels in HDL.

High-density lipoprotein lipid peroxidation in association with presence of coronary artery disease and atrial fibrillation in a large cross-sectional study

Abstract Background The function of high-density lipoprotein (HDL) cholesterol may play a more important role in the prevention of cardiovascular disease compared to the concentration of the HDL. Cardiovascular diseases such as coronary artery disease (CAD) and atrial fibrillation (AF) have been linked to impaired HDL function. Purpose The aim of the present study is to assess a biochemical measure of the antioxidant function of HDL and its association with presence of CAD and AF. Methods Patients admitted for elective cardiac catheterization were recruited in this cross-sectional study. Out of 1231 participants that were included in the analyses, 727 patients had confirmed CAD (CAD group), 369 patients had no CAD (no CAD group) and 129 persons were included as a control group. HDL function was measured in sera by determination of HDL-lipid peroxidation content (HDLox) assessed by a validated fluorometric cell-free biochemical assay and was normalized for the levels of HDL cholesterol (normalized HDLox/HDL-C ratio or nHDLox; no units). Results are expressed as median with interquartile range. Associations of nHDLox with presence of CAD and AF were assessed by univariate and multivariate analyses. Results Participants in the CAD group had higher levels of nHDLox (0.80, 0.61–1.03) compared to the no CAD (0.70, 0.55–0.93) and control (0.66, 0.55–1.03, no units, p&amp;lt;0.001) group. Out of 1206 participants, 233 (19%) had AF and 973 (81%) had no AF. Patients with AF have also higher nHDLox (0.82, 0.60–10.03) compared to persons without AF (0.73, 0.58–0.98, p=0.03). In univariate analysis nHDLox was associated with CAD (p&amp;lt;0.001). In multivariate analysis adjusted for age, gender, CAD, BMI and hypertension, nHDLox was a strong independent predictor of atrial fibrillation (p=0.015) but was not an independent predictor of CAD (p&amp;gt;0.05) Conclusions Reduced antioxidant function of HDL (increased HDLox measured by a biochemical assay), a metric of HDL function, is increased in patients with atherosclerosis and manifested CAD and is also associated with the presence of atrial fibrillation independent of the presence of CAD. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Medical School of Brandenburg-MHB Fontane

High- density lipoprotein function is abnormal in idiopathic inflammatory myopathies.

Damage to the vascular endothelium is strongly implicated in the pathogenesis of idiopathic inflammatory myopathies (IIM). Normally, high-density lipoprotein (HDL) protectsthe vascular endothelium from damage from oxidized phospholipids, which accumulate under conditions of oxidative stress. The current work evaluated the antioxidant function of HDL in IIM patients. HDL's antioxidant function was measured in IIM patients using a cell-free assay, which assesses the ability of isolated patient HDL to inhibit oxidation of low-density lipoproteins and is reported as the HDL inflammatory index (HII). Cholesterol profiles were measured for all patients, and subgroup analysis included assessment of oxidized fatty acids in HDL and plasma MPO activity. A subgroup of IIM patients was compared with healthy controls. The antioxidant function of HDL was significantly worse in patients with IIM (n = 95) compared with healthy controls (n = 41) [mean (S.d.) HII 1.12 (0.61) vs 0.82 (0.13), P < 0.0001]. Higher HII associated with higher plasma MPO activity [mean (S.d.) 13.2 (9.1) vs 9.1 (4.6), P = 0.0006] and higher oxidized fatty acids in HDL. Higher 5-hydroxyeicosatetraenoic acid in HDL correlated with worse diffusion capacity in patients with interstitial lung disease (r = -0.58, P = 0.02), and HDL's antioxidant function was most impaired in patients with autoantibodies against melanoma differentiation-associatedprotein 5 (MDA5) or anti-synthetase antibodies. In multivariate analysis including 182 IIM patients, higher HII was associated with higher disease activity and DM diagnosis. The antioxidant function of HDL is abnormal in IIM patients and may warrant further investigation for its role in propagating microvascular inflammation and damage in this patient population.

Changes in High-Density Lipoproteins Related to Outcomes in Patients with Acute Stroke.

Modifications in high-density lipoprotein (HDL) particle sizes and HDL-binding proteins have been reported in stroke patients. We evaluated whether the lipoprotein profile, HDL composition and functionality were altered in stroke patients according to their clinical outcome using the modified Rankin Score at 3 months. Plasma samples were obtained from stroke patients treated with intravenous thrombolysis. Levels of cardiovascular and inflammatory markers in plasma were measured using the Human CVD Panel 1 (Milliplex® MAP). Lipoprotein subfractions from plasma were quantified by non-denaturing acrylamide gel electrophoresis, using the Lipoprint®-System (Quantimetrix®), and HDLs were isolated by ultracentrifugation. Relative amounts of paraoxonase-1 (PON1) and alpha-1 anti-trypsin (AAT) in the isolated HDLs were determined by Western blot. HDL anti-inflammatory function was evaluated in human blood–brain barrier endothelial cells stimulated with 100 ng/mL TNFα, and HDL antioxidant function was evaluated via their capacity to limit copper-induced low-density lipoprotein oxidation. Stroke patients with unfavorable outcomes had a lower proportion of small-sized HDLs and increased plasma levels of E-selectin (SELE) and the intercellular adhesion molecule 1 (ICAM1). HDLs from patients with unfavorable outcomes had lower levels of PON1 and displayed a blunted capacity to reduce the expression of SELE, interleukin 8 (IL8) and the monocyte chemoattractant protein-1 (MCP1) mRNA induced by TNFα in endothelial cells. These HDLs also had a reduced antioxidant capacity relative to HDLs from healthy donors. In conclusion, an increased ratio of large/small HDLs with impaired anti-inflammatory and antioxidant capacities was associated with unfavorable outcomes in stroke patients. Alteration of HDL functionality was mainly associated with a low amount of PON1 and high amount of AAT.

Τhe Antioxidant Function of HDL in Atherosclerosis

Atherosclerosis is a multistep process that progresses over a long period of time and displays a broad range of severity. In its final form, it manifests as a lesion of the intimal layer of the arterial wall. There is strong evidence supporting that oxidative stress contributes to coronary heart disease morbidity and mortality and antioxidant high-density lipoprotein (HDL) could have a beneficial role in the prevention and prognosis of the disease. Indeed, certain subspecies of HDL may act as natural antioxidants preventing oxidation of lipids on low-density lipoprotein (LDL) and biological membranes. The antioxidant function may be attributed to inhibition of synthesis or neutralization of free radicals and reactive oxygen species by HDL lipids and associated enzymes or transfer of oxidation prone lipids from LDL and biological membranes to HDL for catabolism. A limited number of clinical trials suggest that the increased antioxidant potential of HDL correlates with decreased risk for atherosclerosis. Some nutritional interventions to increase HDL antioxidant activity have been proposed with limited success so far. The limitations in measuring and understanding HDL antioxidant function in vivo are also discussed.

High-density lipoprotein lipid peroxidation as a molecular signature of the risk for developing cardiovascular disease: Results from MASHAD cohort.

High-density lipoprotein (HDL) function rather than level may better predict cardiovascular disease (CVD). However, the contribution of the impaired antioxidant function of HDL that is associated with increased HDL lipid peroxidation (HDLox) to the development of clinical CVD remains unclear. We have investigated the association between serum HDLox with incident CVD outcomes in Mashhad cohort. Three-hundred andthirty individuals who had a median follow-up period of 7 years were recruited as part of the cohort. The primary end point was cardiovascular event, including myocardial infarction, stable angina, unstable angina, or coronary revascularization. In both univariate/multivariate analyses adjusted for traditional CVD risk factors, HDLox was an independent risk factor for CVD (odds ratio, 1.62; 95% confidence interval, 1.41-1.86; p < 0.001). For every increase in HDLox by 0.1 unit, there was an increase in CVD risk by 1.62-fold. In an adjusted analysis, there was a >2.5-fold increase in cardiovascular risk in individuals with HDLox higher than cutoff point of 1.06 compared to those with lower scores, suggesting HDLox > 1.06 is related to the impaired HDL oxidant function and in turn exposed to elevated risk of CVD outcomes (hazard ratio, 2.72; 95% CI, 1.88-3.94). HigherHDLox is a surrogate measure of reduced HDL antioxidant function that positively associated with cardiovascular events in a population-based cohort.

Attenuation of atherogenic apo B-48-dependent hyperlipidemia and high density lipoprotein remodeling induced by vitamin C and E combination and their beneficial effect on lethal ischemic heart disease in mice

Background and aimsAtherosclerotic cardiovascular disease is highly prevalent and its underlying pathogenesis involves dyslipidemia including pro-atherogenic high density lipoprotein (HDL) remodeling. Vitamins C and E have been proposed as atheroprotective agents for cardiovascular disease management. However, their effects and benefits on high density lipoprotein function and remodeling are unknown. In this study, we evaluated the role of vitamin C and E on non HDL lipoproteins as well as HDL function and remodeling, along with their effects on inflammation/oxidation biomarkers and atherosclerosis in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice.Methods and resultsMice were pre-treated for 5 weeks before and during atherogenic diet feeding with vitamin C and E added to water and diet, respectively. Compared to a control group, combined vitamin C and E administration reduced serum total cholesterol and triglyceride levels by decreasing apo B-48-containing lipoproteins, remodeled HDL particles by reducing phospholipid as well as increasing PON1 and apo D content, and diminished PLTP activity and levels. Vitamin supplementation improved HDL antioxidant function and lowered serum TNF-α levels. Vitamin C and E combination attenuated atherogenesis and increased lifespan in atherogenic diet-fed SR-B1 KO/ApoER61h/h mice.ConclusionsVitamin C and E administration showed significant lipid metabolism regulating effects, including HDL remodeling and decreased levels of apoB-containing lipoproteins, in mice. In addition, this vitamin supplementation generated a cardioprotective effect in a murine model of severe and lethal atherosclerotic ischemic heart disease.

Effects of Freeze-Dried Grape Powder on High-Density Lipoprotein Function in Adults with Metabolic Syndrome: A Randomized Controlled Pilot Study.

High-density lipoprotein (HDL) particles are protective against atherosclerosis. However, HDL function is impaired in metabolic syndrome (MetS) due to low-grade inflammation and dyslipidemia. Foods containing polyphenols, such as grapes, may prevent HDL dysfunction via antioxidant or anti-inflammatory effects. We evaluated the effects of grape powder ingestion on measures of HDL function in adults with MetS. Twenty adults (age: 32-70 years; body mass index: 25.3-45.4 kg/m2) consumed either 60 grams/day of freeze-dried grape powder (GRAPE) or a placebo for 4 weeks, separated by a 3-week washout period, in a randomized, double-blind crossover study. The primary outcome was serum paraoxonase-1 (PON1) arylesterase activity, a measure of HDL antioxidant function. Secondary outcomes included PON1 lactonase activity, plasma lipids, metabolic markers, cholesterol efflux capacity, and other HDL functional markers. After 4 weeks, GRAPE did not alter the serum PON1 activity or other markers of HDL function compared with placebo. Measures of HDL function were positively correlated with each other and inversely with measures of insulin resistance and inflammation. GRAPE intake led to a significant reduction in fasting plasma triglycerides compared with placebo (P = 0.032). No other significant effects of GRAPE were observed for other plasma lipids, anthropometrics, or metabolic measures. Grape powder consumption did not impact HDL function in this cohort of adults with MetS. However, it was shown to improve fasting triglycerides, a risk factor for cardiovascular disease.

Gender-related impact on outcomes of high density lipoprotein in acute ST-elevation myocardial infarction

Background and aimsThere is rising evidence that cardioprotective functions of high-density lipoprotein (HDL) have significant impact on clinical outcomes. ST-elevation myocardial infarction (STEMI) represents a high-risk vascular condition. Whether higher HDL-cholesterol concentrations in women correspond to protective anti-oxidant properties in the setting of STEMI is unknown. MethodsWe prospectively assessed gender related differences in the anti-oxidant function of HDL, and the impact of HDL properties on mortality in 242 women and men with STEMI. Blood samples to determine HDL function and sex hormone levels were collected during primary percutaneous coronary intervention. ResultsPatients were stratified according to preserved anti-oxidant HDL function (HDL oxidant index (HOI) < 1) and pro-oxidant HDL (HOI≥1). Despite higher serum levels of HDL-cholesterol in postmenopausal women (48 mg/dl, IQR 42–54, versus 39 mg/dl, IQR33-47, p < 0.001 in men), the proportion of patients with pro-oxidant HDL was not different between women (35%) and men (46%, p = 0.132). Kaplan–Meier analysis revealed higher cardiovascular mortality in both women (p = 0.021) and men (p = 0.045) with pro-oxidant HDL. We identified pro-oxidant HDL as strong and independent predictor of cardiovascular mortality with an adjusted HR of 8.33 (95% CI, 1.55–44.63; p = 0.013) in women and with an adjusted HR of 5.14 (95% CI, 1.61–16.42; p = 0.006) in men. Higher levels of free sex hormones (estradiol and testosterone) were associated with pro-oxidant HDL. HDL-cholesterol levels showed no association with mortality (HR in women 1.03, 95% CI 0.96–1.11, p = 0.45 and HR in men 0.99, 95% CI 0.94–1.05, p = 0.72). ConclusionsTotal HDL-cholesterol serum levels were not associated with mortality in STEMI patients. Pro-oxidant HDL was a strong and independent predictor of mortality in women and men with STEMI. The present study provides a link between sex hormones, HDL function and clinical events in STEMI patients. In clinical practice and future clinical trials, anti-oxidant properties of HDL rather than total HDL serum levels should be used for risk stratification.

Antioxidant properties of HDL.

High-density lipoprotein (HDL) provides a pathway for the passage of lipid peroxides and lysophospholipids to the liver via hepatic scavenger receptors. Perhaps more importantly, HDL actually metabolizes lipid hydroperoxides preventing their accumulation on low-density lipoprotein (LDL), thus impeding its atherogenic structural modification. A number of candidates have been suggested to be responsible for HDL's antioxidant function, with paraoxonase-1 (PON1) perhaps the most prominent. Here we review the evidence for HDL anti-oxidative function and the potential contributions of apolipoproteins, lipid transfer proteins, paraoxonases and other enzymes associated with HDL.

Paraoxonase-3 is depleted from the high-density lipoproteins of autoimmune disease patients with subclinical atherosclerosis.

Patients with autoimmune diseases have a significantly increased risk of developing cardiovascular disease. In disease, high-density lipoprotein (HDL) particles lose their anti-inflammatory and antioxidant properties and become dysfunctional. The purpose of this study was to test the hypothesis that alterations in the HDL proteomic profile are associated with subclinical atherosclerosis and HDL dysfunction in patients with autoimmune diseases such as systemic lupus erythematosus (SLE) and type 1 diabetes. Targeted proteomics was used to quantify the relative abundance of 18 proteins in HDL from SLE patients with and without atherosclerotic plaque detectable by carotid ultrasound. Changes in the proteomic profile were compared against the in vitro ability of HDL to protect against lipid oxidation. The same proteins were quantified in HDL from patients with type 1 diabetes with or without coronary artery calcification as determined by computed tomography. In each population, paraoxonase-3 (PON3), a potent antioxidant protein, was depleted from the HDL of patients with subclinical atherosclerosis. PON3 expression in HDL was positively correlated with HDL antioxidant function. These results suggest that PON3 may be an important protein in preventing atherosclerosis and highlight the importance of antioxidant proteins in the prevention of atherosclerosis in vivo.

Impairment of high-density lipoprotein resistance to lipid peroxidation and adipose tissue inflammation in obesity complicated by obstructive sleep apnea.

Obstructive sleep apnea (OSA) complicates morbid obesity and is associated with increased cardiovascular disease incidence. An increase in the circulating markers of chronic inflammation and dysfunctional high-density lipoprotein (HDL) occur in severe obesity. The objective of the study was to establish whether the effects of obesity on inflammation and HDL dysfunction are more marked when complicated by OSA. Morbidly obese patients (n = 41) were divided into those whose apnea-hypoapnea index (AHI) was more or less than the median value and on the presence of OSA [OSA and no OSA (nOSA) groups]. We studied the antioxidant function of HDL and measured serum paraoxonase 1 (PON1) activity, TNFα, and intercellular adhesion molecule 1 (ICAM-1) levels in these patients. In a subset of 19 patients, we immunostained gluteal sc adipose tissue (SAT) for TNFα, macrophages, and measured adipocyte size. HDL lipid peroxide levels were higher and serum PON1 activity was lower in the high AHI group vs the low AHI group (P < .05 and P < .0001, respectively) and in the OSA group vs the nOSA group (P = .005 and P < .05, respectively). Serum TNFα and ICAM-1 levels and TNFα immunostaining in SAT increased with the severity of OSA. Serum PON1 activity was inversely correlated with AHI (r = -0.41, P < .03) in the OSA group. TNFα expression in SAT directly correlated with AHI (r = 0.53, P < .03) in the subset of 19 patients from whom a biopsy was obtained. Increased serum TNFα, ICAM-1, and TNFα expression in SAT provide a mechanistic basis for enhanced inflammation in patients with OSA. Decreased serum PON1 activity, impaired HDL antioxidant function, and increased adipose tissue inflammation in these patients could be a mechanism for HDL and endothelial dysfunction.

Effect of PON1 Q192R Genetic Polymorphism on Clopidogrel Efficacy and Cardiovascular Events in the Clopidogrel in the Unstable Angina to Prevent Recurrent Events Trial and the Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events

A recent report suggested that carriers of the Q allele of the PON1 Q192R polymorphism had decreased biotransformation of clopidogrel into its active metabolite and decreased efficacy of clopidogrel in preventing cardiovascular events. Furthermore, PON1 has been reported to have a central role in the antioxidant function of high-density lipoprotein, and the Q192R polymorphism has been previously associated with cardiovascular risk in patients not treated with clopidogrel. Patients (n=5059) from the Clopidogrel in Unstable Angina to Prevent Recurrent Events (CURE) randomized trial that demonstrated benefits of clopidogrel versus placebo in preventing cardiovascular events in acute coronary syndromes were genotyped for the PON1 Q192R polymorphism. Clopidogrel compared with placebo significantly reduced the first primary efficacy outcome, irrespective of PON1 Q192R genotype (P=0.07 for heterogeneity). No association was observed between the Q192R polymorphism and cardiovascular events in the overall sample (hazard ratio [HR], 1.09 per allele; 95% confidence interval [CI], 0.95-1.24; P=0.23). However, an association was observed between the Q allele and increased cardiovascular events in the placebo group (HR, 1.23 per allele; 95% CI, 1.03-1.47; P=0.03) but not in the clopidogrel group (HR, 0.93 per allele; 95% CI, 0.76-1.13; P=0.46). In 1156 atrial fibrillation patients from the Atrial Fibrillation Clopidogrel Trial With Irbesartan for Prevention of Vascular Events, there was no evidence of interaction between PON1 genotype and clopidogrel for any outcome or for an association between genotype and cardiovascular events. In conclusion, our study shows that PON1 Q192R genotype does not modify the efficacy and safety of clopidogrel in patients with acute coronary syndromes. Further studies are needed to confirm or refute the association of the Q allele with adverse cardiovascular events independent of clopidogrel in secondary prevention patients.

Cholesterol efflux by high density lipoproteins is impaired in patients with active rheumatoid arthritis

ObjectivesReverse cholesterol transport (RCT) is a major antiatherogenic function of high density lipoprotein (HDL). In the current work, the authors evaluated whether the RCT capacity of HDL from rheumatoid arthritis...

Low physical activity is associated with proinflammatory high‐density lipoprotein and increased subclinical atherosclerosis in women with systemic lupus erythematosus

To investigate the association between physical activity, functional activity of high-density lipoprotein (HDL), and subclinical cardiovascular disease in patients with systemic lupus erythematosus (SLE). A total of 242 SLE patients (all women) participated in this cross-sectional study from February 2004 to February 2008. Carotid plaque and intima-media thickness (IMT), antioxidant function of HDL, and traditional cardiac risk factors were measured. Physical activity was assessed from self-reports by calculating the metabolic equivalents (METS) per week and by the physical function domain of the Medical Outcomes Study Short Form 36 (SF-36). Data were analyzed using bivariate and multivariate regression analyses. Number of METS per week spent performing strenuous exercise was negatively correlated with IMT (r = -0.4, P = 0.002) and number of plaques (r = -0.30, P = 0.0001). Physical function as assessed by the SF-36 was also negatively correlated with IMT (r = -0.14, P = 0.03) and number of plaques (r = -0.14, P = 0.04). In multivariate analyses, number of strenuous exercise METS was significantly associated with IMT (t = -2.2, P = 0.028) and number of plaques (t = -2.5, P = 0.014) when controlling for markers of SLE disease activity and damage, but not after controlling for traditional cardiac risk factors. Low physical activity, defined as <225 total METS per week, was associated with the presence of proinflammatory HDL (P = 0.03). Low physical activity is associated with increased subclinical atherosclerosis and proinflammatory HDL in patients with SLE. Increased strenuous exercise may reduce the risk of atherosclerosis in SLE.