Antioxidant Capacity Of High-density Lipoprotein Research Articles

Regular Practice of Physical Activity Improves Cholesterol Transfers to High-Density Lipoprotein (HDL) and Other HDL Metabolic Parameters in Older Adults

The effects of regular physical activity on two important anti-atherosclerosis functions of high-density lipoprotein (HDL), namely its capacity to receive both forms of cholesterol and its anti-oxidant function, were investigated in this study comparing older adults with young individuals. One-hundred and eight healthy adult individuals were enrolled and separated into the following groups: active older (60–80 yrs, n = 24); inactive older (60–79 yrs, n = 21); active young (20–34 yrs, n = 39); and inactive young (20–35 yrs, n = 24). All performed cardiopulmonary tests. Blood samples were collected in order to assess the following measures: lipid profile, HDL anti-oxidant capacity, paraoxonase-1 activity, HDL subfractions, and lipid transfer to HDL. Comparing active older and active young groups with inactive older and inactive young groups, respectively, the active groups presented higher HDL-C levels (p < 0.01 for both comparisons), unesterified cholesterol transfer (p < 0.01, p < 0.05), and intermediate and larger HDL subfractions (p < 0.001, p < 0.01) than the respective inactive groups. In addition, the active young group showed higher esterified cholesterol transfer than the inactive young group (p < 0.05). As expected, the two active groups had higher VO2peak than the inactive groups; VO2peak was higher in the two younger than in the two older groups (p < 0.05). No differences in unesterified and esterified cholesterol transfers and HDL subfractions were found between active young and active older groups. HDL anti-oxidant capacity and paraoxonase-1 activity were equal in all four study groups. Our data highlight and strengthen the benefits of regular practice of physical activity on an important HDL function, the capacity of HDL to receive cholesterol, despite the age-dependent decrease in VO2peak.

Associations of High-Density Lipoprotein Functionality with Coronary Plaque Characteristics in Diabetic Patients with Coronary Artery Disease: Integrated Backscatter Intravascular Ultrasound Analysis.

High-density lipoprotein (HDL) functionality has been reported to be associated with coronary artery disease (CAD). However, little is known about the impact of HDL functionality on coronary atherosclerosis. Thirty-eight type 2 diabetic patients with CAD who underwent percutaneous coronary intervention were examined. Coronary atheroma burden and plaque composition of the culprit lesions were assessed using conventional gray-scale and integrated backscatter intravascular ultrasound. HDL-mediated cholesterol efflux capacity (HDL-CEC) and HDL antioxidant capacity, estimated as HDL inflammatory index (HII), were examined. The associations between HDL functionality and coronary plaques were analyzed using multivariate data analysis, including principal components analysis and orthogonal partial least squares (OPLS) models. Percent atheroma volume was correlated with HDL-CEC (r = 0.34, p = 0.04) but not with HII (p = 0.65). The OPLS model demonstrated that the percentage lipid volume was significantly associated with HDL functionality [coefficient (95% confidence interval); HDL-CEC: -0.26 (-0.49, -0.04); HII: 0.34 (0.08, 2.60), respectively]. HII exhibited the highest variable importance in projection score, indicating the greatest contribution. HDL functionality was associated with coronary plaque composition, a key component of plaque vulnerability. Our findings highlight the potential importance of HDL functionality for coronary plaque stabilization.

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.

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.

Asociación de la actividad física con la funcionalidad de las lipoproteínas de alta densidad en una cohorte de base poblacional: el estudio REGICOR

Introduction and objectivesTo determine the dose-response association between current and past leisure-time physical activity (LTPA), total and at different intensities, and high-density lipoprotein (HDL) functionality parameters. MethodsStudy participants (n=642) were randomly drawn from a large population-based survey. Mean age of the participants was 63.2 years and 51.1% were women. The analysis included data from a baseline and a follow-up visit (median follow-up, 4 years). LTPA was assessed using validated questionnaires at both visits. Two main HDL functions were assessed: cholesterol efflux capacity and HDL antioxidant capacity, at the follow-up visit. Linear regression and linear additive models were used to assess the linear and nonlinear association between LTPA and HDL functionality. ResultsTotal LTPA at follow-up showed an inverse and linear relationship between 0 and 400 METs x min/d with HDL antioxidant capacity (regression coefficient [beta]: −0.022; 95%CI, −0.030, −0.013), with a plateau above this threshold. The results were similar for moderate (beta: −0.028; 95%CI, −0.049, −0.007) and vigorous (beta: −0.025; 95%CI, −0.043, −0.007), but not for light-intensity LTPA. LTPA at follow-up was not associated with cholesterol efflux capacity. Baseline LTPA was not associated with any of the HDL functionality parameters analyzed. ConclusionsCurrent moderate and vigorous LTPA showed a nonlinear association with higher HDL antioxidant capacity. Maximal benefit was observed with low-intermediate doses of total LTPA (up to 400 METs x min/d). Our results agree with current recommendations for moderate-vigorous LTPA practice and suggest an association between PA and HDL functionality in the general population.Full English text available from:www.revespcardiol.org/en

Association of physical activity with high-density lipoprotein functionality in a population-based cohort: the REGICOR study

Introduction and objectivesTo determine the dose-response association between current and past leisure-time physical activity (LTPA), total and at different intensities, and high-density lipoprotein (HDL) functionality parameters. MethodsStudy participants (n=642) were randomly drawn from a large population-based survey. Mean age of the participants was 63.2 years and 51.1% were women. The analysis included data from a baseline and a follow-up visit (median follow-up, 4 years). LTPA was assessed using validated questionnaires at both visits. Two main HDL functions were assessed: cholesterol efflux capacity and HDL antioxidant capacity, at the follow-up visit. Linear regression and linear additive models were used to assess the linear and nonlinear association between LTPA and HDL functionality. ResultsTotal LTPA at follow-up showed an inverse and linear relationship between 0 and 400 METs x min/d with HDL antioxidant capacity (regression coefficient [beta]: −0.022; 95%CI, −0.030, −0.013), with a plateau above this threshold. The results were similar for moderate (beta: −0.028; 95%CI, −0.049, −0.007) and vigorous (beta: −0.025; 95%CI, −0.043, −0.007), but not for light-intensity LTPA. LTPA at follow-up was not associated with cholesterol efflux capacity. Baseline LTPA was not associated with any of the HDL functionality parameters analyzed. ConclusionsCurrent moderate and vigorous LTPA showed a nonlinear association with higher HDL antioxidant capacity. Maximal benefit was observed with low-intermediate doses of total LTPA (up to 400 METs x min/d). Our results agree with current recommendations for moderate-vigorous LTPA practice and suggest an association between PA and HDL functionality in the general population.

Oxidized low density lipoprotein and paraoxonase activity in coronary artery disease

&#x0D; Background: High-density lipoprotein (HDL) has a reverse relation with incidence of coronary artery disease (CAD). Paraoxonase (PON) is an HDL associated enzyme responsible for antioxidant capacity of HDL. Oxidative modification of LDL results in formation of oxLDL. This can be reduced by Paraoxonase, which has anti-inflammatory and antioxidant function. Aim: To evaluate and compare the level of HDL, oxLDL and Paraoxonase (PON) activity in Coronary Artery Disease patients with controls. Effort was also made to correlate HDL with PON, also to correlate OxLDL with PON and HDL. Materials and Method: 60 clinically proven CAD patients within the age group of 35 to 70 were selected from OPD of Dr. Somervell Memorial CSI Medical College, Kerala. 60 controls within the same age group without any history of CAD was selected from subjects coming for Health Checkup. Results: HDL and PON were significantly lowered in CAD patients than in controls (P&lt;0.05). OxLDL, Total Cholesterol, Triglyceride, LDL and VLDL were significantly higher in CAD patients than in controls (P&lt;0.05). Correlation Analysis showed a positive correlation of HDL and PON. Statistically significant negative correlation was observed in case of oxLDL with PON and HDL.

Modification of High-Density Lipoprotein Functions by Diet and Other Lifestyle Changes: A Systematic Review of Randomized Controlled Trials.

High-density lipoprotein (HDL) functional traits have emerged as relevant elements that may explain HDL antiatherogenic capacity better than HDL cholesterol levels. These properties have been improved in several lifestyle intervention trials. The aim of this systematic review is to summarize the results of such trials of the most commonly used dietary modifications (fatty acids, cholesterol, antioxidants, alcohol, and calorie restriction) and physical activity. Articles were screened from the Medline database until March 2021, and 118 randomized controlled trials were selected. Results from HDL functions and associated functional components were extracted, including cholesterol efflux capacity, cholesteryl ester transfer protein, lecithin-cholesterol acyltransferase, HDL antioxidant capacity, HDL oxidation status, paraoxonase-1 activity, HDL anti-inflammatory and endothelial protection capacity, HDL-associated phospholipase A2, HDL-associated serum amyloid A, and HDL-alpha-1-antitrypsin. In mainly short-term clinical trials, the consumption of monounsaturated and polyunsaturated fatty acids (particularly omega-3 in fish), and dietary antioxidants showed benefits to HDL functionality, especially in subjects with cardiovascular risk factors. In this regard, antioxidant-rich dietary patterns were able to improve HDL function in both healthy individuals and subjects at high cardiovascular risk. In addition, in randomized trial assays performed mainly in healthy individuals, reverse cholesterol transport with ethanol in moderate quantities enhanced HDL function. Nevertheless, the evidence summarized was of unclear quality and short-term nature and presented heterogeneity in lifestyle modifications, trial designs, and biochemical techniques for the assessment of HDL functions. Such findings should therefore be interpreted with caution. Large-scale, long-term, randomized, controlled trials in different populations and individuals with diverse pathologies are warranted.

L-Glutamine supplementation enhances glutathione peroxidase and paraoxonase-1 activities in HDL of exercising older individuals.

Oxidative stress is an important factor in the formation of atherosclerotic plaques. High-density lipoprotein (HDL) harbors paraoxonase-1 (PON-1) and glutathione peroxidase (GPx), key enzymes in the protection against the harmful effects of oxidative stress. Although exercise training can increase both HDL-c content and its antioxidant action, and glutamine (Gln) intake also promotes GPx-based defenses, the association between exercise training and Gln in the regulation of PON-1 activity was not explored. Therefore, the objective of this study was to investigate the effects of Gln supplementation on the redox balance and on the total HDL antioxidant capacity by evaluation of the activity of PON-1 and GPx enzymes in physically exercised elderly individuals compared to non-exercised ones. Fifty-one practitioners of a combined exercise training program (CET, age: 71.9±5.7years) and 32 non-practitioners (NP, age: 73±6.3years) participated in the study. CET and NP groups were separated into 2 subgroups according to the supplementation: Gln, 0.3g/kg/day + 10g maltodextrin (CET-Gln, n=26; and NP-Gln, n=16) or placebo, 10g maltodextrin (CET-PL, n=25; and NP-PL, n=16). Blood samples were drawn at baseline and after 30days after commencement of the supplementation for biochemical and enzyme activity analyses. Increased HDL-c, total peroxidase (PRx), and GPx activities were found in both CET-Gln and NP-Gln after the supplementation period, compared to baseline, in opposition to CET-PL and NP-PL groups. PON-1 activity increased only in CET-Gln. In both CET-Gln and NP-Gln groups, there was a reduction of the total peroxides/PRx, iron/PRx, and total peroxides/GPX ratios after supplementation. In CET-Gln, thiobarbituric acid-reactive substances (TBARS)/PRx and TBARS/GPx ratios were also lower after supplementation. CET-Gln and CET-PL subgroups had lower glycemia than NP-Gln and NP-PL, either at baseline or after the supplementation periods. The other parameters were unchanged after supplementation [total cholesterol, LDL-c, triglycerides, non-HDL cholesterol, total peroxides, TBARS, iron serum, Trolox-equivalent antioxidant capacity (TEAC), and uric acid]. Gln supplementation can increase glutathione peroxidase activity regardless the individuals were physically active or sedentary, but the PON-1 activity only increased in physically active individuals. These results show the potential of Gln supplementation in the maintenance of the vascular redox balance, with potential implications for atherogenesis protection.

Association of anti-oxidative capacity of HDL with subclinical atherosclerosis in subjects with and without non-alcoholic fatty liver disease

BackgroundNon-alcoholic fatty liver disease (NAFLD) patients are at a substantial risk for developing cardiovascular disease (CVD). High-density lipoprotein (HDL) is well known to have protective effects against the development of atherosclerotic CVD. One of the major antiatherogenic effects of HDL is its anti-oxidative function.ObjectivesThis study investigated the association of anti-oxidative capacity of HDL with subclinical atherosclerosis in NAFLD and non-NAFLD subjects.MethodsA total of 143 subjects including 51 NAFLD and 92 control subjects were included in this case–control study. HDL oxidative index (HOI) was determined spectrophotometrically using a cell-free method in the presence of a fluorescent substrate dichlorofluorescein diacetate (DCFDA). Paraoxonase 1 (PON1) activity, superoxide dismutase (SOD) activity, and malondialdehyde (MDA) plasma levels were assessed in both groups.ResultsThe NAFLD patients with impaired HDL anti-oxidative function (HOI ≥ 1) had higher MDA levels, aspartate amino transferase (AST), liver stiffness (LS), and carotid intima-media thickness (cIMT) values compared to the controls. HDL oxidative index (HOI) was positively correlated with MDA levels and cIMT and negatively correlated with SOD activity.ConclusionsHigher circulating levels of MDA were associated with the impaired anti-oxidative function of HDL in NAFLD. The impaired anti-oxidative capacity of HDL might be related to NAFLD severity and subclinical atherosclerosis in NAFLD patients.

Adiponectin predicts the antioxidant capacity and size of high-density lipoprotein (HDL) in individuals with diabetes mellitus.

The relationship between adiponectin and type 2 diabetes mellitus (T2DM) is established; however the evidence on its role in high-density lipoprotein (HDL) functionality is still scant. The aim of this study was to assess the association of adiponectin with HDL functionality especially on the antioxidant capacity and HDL subfractions in individuals with T2DM. This case-control study enrolled 356 individuals who were divided into two groups: diabetics [T2DM (n = 188)] and non-diabetic [nT2DM (n = 168)]. The association of adiponectin level on HDL functionality parameters was done in function of the cut-off point for adiponectin [percentile p < 75 = 12.9 μg/mL versus p ≥ 75 = 12.9 μg/mL] and multiple adjustments applied in the logistic regression models. Body mass index (BMI), waist circumference (WC) and body fat mass (FM) were higher in T2DM. The larger HDL particles (HDLLARGE) were lower in T2DM group in comparison with nT2DM (28.20% versus 30.40%; p = 0.016). Individuals with T2DM and simultaneous highest adiponectin (p ≥ 75) had 2.25 OR (95% CI = 1.03-4.91) and 5.14 OR (95% CI = 2.37-11.15) to present higher HDL-C and HDLLARGE concentrations. After adjustment for multiple confounders, high level of adiponectin was independently related with improvement of the HDL antioxidant capacity (OR = 2.78; 95% CI = 1.16-6.67). High adiponectin level associates with a lesser negative impact of T2DM on HDL functionality by increase in APO AI, particles size, and cholesterol content. On the same token, higher adiponectin was associated with greater odds to have high antioxidant capacity.

Hydrogen influences HDL-associated enzymes and reduces oxidized phospholipids levels in rats fed with a high-fat diet

AimsOxidized phospholipids (OxPLs) are formed as a result of oxidative stress, which potentially mediate multiple pathological effects. We aimed to evaluate the effects of hydrogen (H2) on OxPLs in vivo and the underlying mechanism. Main methodsRats were randomly assigned to three groups: control group fed with a chow diet, model group fed with a high-fat diet, and H2-treated group fed with a high-fat diet and treated by 4% H2 inhalation for ten weeks. OxPLs in liver and plasma were analyzed by liquid chromatography–mass spectrometry. High-density lipoprotein (HDL) was separated by ultracentrifugation. A proteomic analysis was performed to reveal the alternation of HDL protein composition and he antioxidant capacity of HDL was tested by low-density lipoprotein oxidation experiment. Furthermore, the activity or expression of HDL-associated enzymes were evaluated. Key findingsInhalation of 4% H2 decreased the accumulation of OxPLs in rats. In vitro tests revealed that the different concentrations of H2 did not inhibit the formation of OxPLs mediated by non-enzymatic oxidation. H2 inhalation altered the components and enhanced the anti-oxidative capacity of HDL in rats fed with a high-fat diet. Further experiments showed that H2 significantly regulated the activity of lipoprotein-associated phospholipase A2, paraoxonase-1, and the expression of lecithin:cholesterol acyltransferase. SignificanceOur findings revealed that H2 may reduce the OxPLs levels through its influence on HDL-associated enzymes that can act on OxPLs, suggesting that H2 can be used in alleviating diseases related to lipid peroxidation due to oxidative stress.

HDL Cholesterol Efflux Capacity is Impaired in Severe Short-Term Hypothyroidism Despite Increased HDL Cholesterol.

Severe hypothyroidism has profound effects on lipoprotein metabolism including high-density lipoprotein (HDL) cholesterol elevations but effects on HDL function metrics are unknown. To determine the impact of severe short-term hypothyroidism on HDL particle characteristics, HDL cholesterol efflux capacity (CEC), and HDL antioxidative capacity. Observational study with variables measured during severe short-term hypothyroidism (median TSH 81 mU/L) and after 20 weeks of thyroid hormone supplementation (median TSH 0.03 mU/L) (Netherlands Trial Registry ID 7228). University hospital setting in The Netherlands. Seventeen patients who had undergone a total thyroidectomy for differentiated thyroid carcinoma. HDL particle characteristics (nuclear magnetic resonance spectrometry), CEC (human THP-1-derived macrophage foam cells and apolipoprotein B-depleted plasma), and HDL anti-oxidative capacity (inhibition of low-density lipoprotein oxidation). During hypothyroidism plasma total cholesterol, HDL cholesterol and apolipoprotein A-I were increased (P ≤ 0.001). HDL particle concentration was unchanged, but there was a shift in HDL subclasses toward larger HDL particles (P < 0.001). CEC was decreased (P = 0.035), also when corrected for HDL cholesterol (P < 0.001) or HDL particle concentration (P = 0.011). HDL antioxidative capacity did not change. During severe short-term hypothyroidism CEC, an important antiatherogenic metric of HDL function, is impaired. HDL cholesterol and larger HDL particles are increased but HDL particle concentration is unchanged. Combined, these findings suggest that HDL quality and quantity are not improved, reflecting dysfunctional HDL in hypothyroidism.

Endothelial lipase increases antioxidative capacity of high-density lipoprotein

Endothelial lipase (EL) is a strong determinant of structural and functional properties of high-density lipoprotein (HDL). We examined whether the antioxidative capacity of HDL is affected by EL. EL-modified HDL (EL-HDL) and control EV-HDL were generated by incubation of HDL with EL- overexpressing or control HepG2 cells. As determined by native gradient gel electrophoresis, electron microscopy, and small-angle X-ray scattering EL-HDL is smaller than EV-HDL. Mass spectrometry revealed an enrichment of EL-HDL with lipolytic products and depletion of phospholipids and triacylglycerol. Kinetics of conjugated diene formation and HPLC-based malondialdehyde quantification revealed that EL-HDL exhibited a significantly higher resistance to copper ion-induced oxidation and a significantly higher capacity to protect low-density lipoprotein (LDL) from copper ion-induced oxidation when compared to EV-HDL. Depletion of the lipolytic products from EL-HDL abolished the capacity of EL-HDL to protect LDL from copper ion-induced oxidation, which could be partially restored by lysophosphatidylcholine enrichment. Proteomics of HDL incubated with oxidized LDL revealed significantly higher levels of methionine 136 sulfoxide in EL-HDL compared to EV-HDL. Chloramine T (oxidizes methionines and modifies free thiols), diminished the difference between EL-HDL and EV-HDL regarding the capacity to protect LDL from oxidation. In absence of LDL small EV-HDL and EL-HDL exhibited higher resistance to copper ion-induced oxidation when compared to respective large particles. In conclusion, the augmented antioxidative capacity of EL-HDL is primarily determined by the enrichment of HDL with EL-generated lipolytic products and to a lesser extent by the decreased HDL particle size and the increased activity of chloramine T-sensitive mechanisms.

Immature surfactant protein-B impairs the antioxidant capacity of HDL

Circulating immature surfactant protein B (proSP-B) forms emerged as the most reliable lung-specific circulating marker for alveolar-capillary membrane (ACM) dysfunction and for the overall clinical status of heart failure (HF). Notably, in terms of HF hospitalization, immature SP-B overwhelms the prognostic role of other most frequently used clinical parameters such as those related to lung dysfunction. The strong prognostic value of circulating proSP-B in HF suggests more widespread and possible systemic effects. Thus, we assessed the plasma distribution of proSP-B evaluating whether it exists in a lipoprotein-bound form and its impact on lipoprotein structure and function.ProSP-B forms were detectable in high-density lipoprotein (HDL) only. To assess the impact of proSP-B on HDL, HDL from healthy subjects were enriched with proSP-B produced by a stably transfected CHO cell line that specifically expresses and releases the human proSP-B. After enrichment, HDL size and lipoprotein electrophoretic mobility, and protein composition did not show apparent differences. HDL antioxidant capacity (HOI), assessed as their ability to inhibit air-induced LDL oxidation, was impaired after proSP-B enrichment. HOI was also higher in HF patients with respect to age-matched control healthy subjects (p = 0.013).Circulating proSP-B, besides its potential role as a specific marker for ACM dysfunction in HF patients with diagnostic and prognostic value, binds to human HDL impairing their antioxidant capacity. These findings shed light on proSP-B as a molecule that contributes to the reduction of the defense against oxidative stress, a key mediator in the pathogenesis of HF.

Increased PON lactonase activity in morbidly obese patients is associated with impaired lipid profile.

The paraoxonase-1 (PON1) enzyme could play an important role in the anti-oxidant capacity of high-density lipoprotein. However, there are no studies which analyse the evolution of the three activities of PON1 (PON arylesterase, PON paraoxonase and PON lactonase) after Roux-en-Y Gastric Bypass (RYGB) in morbidly obese subjects. We analysed the association of PON concentration and activities with the evolution of morbidly obese subjects who underwent RYGB, and its relationship with biochemical variables and different atherogenic indices. Twenty-seven non-obese and 82 morbidly obese subjects were studied before and 6months after RYGB. Before RYGB, morbidly obese subjects had a lower PON1 concentration (P<0.05) and higher PON lactonase activity (P<0.001) than non-obese subjects, with no differences in PON arylesterase and PON paraoxonase activities. After RYGB, PON1 concentration (P<0.05) and PON lactonase activity (P<0.001) decreased with regard to the presurgery state. PON lactonase activity correlated with the atherogenic index of plasma before (r=0.19, P=0.047) and after RYGB (r=0.27, P=0.035). In different multiple lineal regression analysis models, presurgery PON lactonase activity was associated with total cholesterol (β=0.909, P<0.001), LDL (β=0.632, P=0.006) and DBP (β=0.230, P=0.030) (R2 =0.295), postsurgery PON lactonase activity was associated with esterified cholesterol (β=0.362, P=0.011) (R2 =0.131), and the change (Δ) in PON lactonase activity after RYGB was associated with Δesterified cholesterol (β=0.304, P=0.030) (R2 =0.093). PON lactonase activity is associated with the presence of morbid obesity and with an impaired lipid profile. All associations found could indicate the relationship between PON lactonase activity and the development of atherosclerosis.

High-Density Lipoprotein Particles, Cell-Cholesterol Efflux, and Coronary Heart Disease Risk.

Objective- The cell-cholesterol efflux capacity of HDL (high-density lipoprotein) is inversely associated with coronary heart disease risk. ABCA1 (ATP-binding cassette transporter A1) plays a crucial role in cholesterol efflux from macrophages to preβ-1-HDL. We tested the hypothesis that coronary heart disease patients have functionally abnormal preβ-1-HDL. Approach and Results- HDL cell-cholesterol efflux capacity via the ABCA1 and the SR-BI (scavenger receptor class B type I) pathways, HDL antioxidative capacity, apo (apolipoprotein) A-I-containing HDL particles, and inflammatory- and oxidative-stress markers were measured in a case-control study of 100 coronary heart disease cases and 100 sex-matched controls. There were significant positive correlations between ABCA1-dependent cholesterol efflux and the levels of small lipid-poor preβ-1 particles ( R2=0.535) and between SR-BI-dependent cholesterol efflux and the levels of large lipid-rich (α-1+α-2) HDL particles ( R2=0.712). Cases had significantly higher (87%) preβ-1 concentrations than controls, but the functionality of their preβ-1 particles (preβ-1 concentration normalized ABCA1-dependent efflux capacity) was significantly lower (-31%). Cases had significantly lower (-12%) mean concentration of large HDL particles, but the functionality of their particles (α-1+α-2 concentration normalized SR-BI-dependent efflux capacity) was significantly higher (22%) compared with that of controls. HDL antioxidative capacity was significantly lower (-16%) in cases than in controls. There were no significant correlations between either preβ-1 functionality or large HDL particle functionality with HDL antioxidative capacity or the concentrations of inflammatory- and oxidative-stress markers. Conclusions- HDL cell-cholesterol efflux capacity is significantly influenced by both the concentration and the functionality of specific HDL particles participating in cell-cholesterol efflux. Coronary heart disease patients have higher than normal preβ-1 concentrations with decreased functionality and lower than normal large HDL particle concentrations with enhanced functionality.

Abstract 383: HDL Particles, Cell-Cholesterol Efflux, and CHD Risk: the Preβ-1 Paradox

Objective: The cell-cholesterol efflux capacity (CEC) of high-density lipoprotein (HDL) is inversely associated with coronary heart disease (CHD) risk. ATP-binding cassette transporter-A1 (ABCA1) plays a crucial role in cholesterol efflux from macrophages to preβ-1-HDL. We tested the hypothesis that CHD patients have functionally abnormal preβ-1-HDL. Approach and Results: We measured HDL CEC via the ABCA1 and the scavenger receptor class B type-I (SR-BI) pathways, HDL anti-oxidative capacity, apolipoprotein A-I-containing HDL particles, and inflammatory- and oxidative-stress markers in 64 CHD cases and 64 gender-matched controls. There were significant positive correlations between ABCA1-dependent cholesterol efflux and the levels of small lipid-poor preβ-1-particles in both cases (R 2 =0.541) and controls (R 2 =0.350). Cases had almost twice the levels of preβ-1-HDL than controls, but the functionality of their preβ-1 particles (preβ-1-concentration-normalized ABCA1-dependent efflux capacity) was significantly lower (-39%). There were significant positive correlations between SR-BI-dependent cholesterol efflux and the levels of large lipid-rich (α-1 + α-2) HDL particles in both cases (R 2 =0.828) and controls (R 2 =0.671). Cases had significantly lower (-11%) levels of large HDL particles, but the functionality of their particles (large-HDL-concentration-normalized SR-BI-dependent efflux capacity) was significantly higher (+27%) compared to controls. High plasma levels of inflammatory and oxidative stress markers were not associated with the functionality of HDL particles. High plasma levels of triglycerides were associated with increased HDL particle functionality. HDL anti-oxidative capacity was significantly lower (-15%) in cases than in controls. There were no significant correlations between HDL anti-oxidative capacity and the concentrations of inflammatory- and oxidative-stress markers or HDL CEC. Conclusions: HDL CEC is significantly influenced by both the concentration and the functionality of specific HDL particles. CHD patients have higher than normal preβ-1 concentration with decreased functionality and lower than normal large-HDL particle concentration with enhanced functionality.

Remodeling of the HDL proteome with treatment response to abatacept or adalimumab in the AMPLE trial of patients with rheumatoid arthritis

Background and aimsTo evaluate changes in the high-density lipoprotein (HDL) proteome and HDL function in active rheumatoid arthritis (RA) patients initiating therapy with abatacept or adalimumab in the Abatacept Versus Adalimumab Comparison in Biologic-Naïve RA Subjects with Background Methotrexate (AMPLE) study. MethodsUltra high-pressure liquid chromatography (UHPLC) coupled with ion mobility mass spectrometry (LC-IM-MS) was used to analyze proteins associated with immunoaffinity-captured HDL from plasma of 30 patients with RA randomized to either abatacept (n = 15) or adalimumab (n = 15) therapy. Paraoxonase 1 (PON1) activity, HDL anti-oxidant capacity, cholesterol profiles, and homocysteine levels were also measured at baseline and following treatment. Repeated-measures analyses were performed using mixed-effect linear models to model the within-subject covariance over time. ResultsIn models controlling for age, sex and treatment group, improvement in inflammation measured by decreases in CRP was associated with improvement in HDL function and changes in several HDL-associated proteins including significant decreases in lipopolysaccharide-binding protein, serum amyloid A-I (SAA-I) and inter-alpha-trypsin inhibitor heavy chain H4 (p values < 0.05). Improvement in disease activity was also associated with changes in multiple HDL-associated proteins. Adalimumab was associated with higher PON1 activity, HDL-associated serotransferrin, and HDL-associated immunoglobulin J chain, and lower HDL-associated SAA-I over time compared with abatacept. ConclusionsImprovement in inflammation associated with treatment of RA, using either abatacept or adalimumab in the AMPLE study, was associated with improvement in HDL function and significant alterations in the HDL proteome, including proteins involved in the immune response, proteinase inhibition, and lipid metabolism.

Effect of tofacitinib on lipid levels and lipid-related parameters in patients with moderate to severe psoriasis

Psoriasis is a systemic inflammatory disease associated with increased cardiovascular (CV) risk and altered lipid metabolism. Tofacitinib is an oral Janus kinase inhibitor. The aim of the study was to investigate the effects of tofacitinib on traditional and nontraditional lipid parameters and CV risk markers in patients with psoriasis from a phase III study, OPT Pivotal1. Patients with psoriasis were randomized to tofacitinib 5 or 10mg twice daily (BID) or placebo BID. Serum samples were collected at baseline, week 4, and week 16. Analyses included serum cholesterol levels, triglycerides, lipoproteins, lipid particles, lipid-related parameters/CV risk markers, and high-density lipoprotein (HDL) function analyses. At week 16, small concurrent increases in mean low-density lipoprotein cholesterol (LDL-C) and HDL cholesterol (HDL-C) levels were observed with tofacitinib; total cholesterol/HDL-C ratio did not change. There was no significant change in the number of small dense LDL particles, which are considered to be more atherogenic than large particles, and oxidized LDL did not increase. Paraoxonase 1 activity, linked to HDL antioxidant capacity, increased, and HDL-associated serum amyloid A, which reduces the anti-atherogenic potential of HDL, decreased. HDL capacity to promote cholesterol efflux from macrophages did not change. Lecithin-cholesterol acyltransferase activity, which is associated with reverse cholesterol transport, increased. Markers of systemic inflammation, serum amyloid A and C-reactive protein, decreased with tofacitinib. While small increases in lipid levels are observed with tofacitinib treatment in patients with psoriasis, effects on selected lipid-related parameters and other circulating CV risk biomarkers are not suggestive of an increased CV risk [NCT01276639].