Effects of Cardiac Rehabilitation on High-Density Lipoprotein-mediated Cholesterol Efflux Capacity and Paraoxonase-1 Activity in Patients with Acute Coronary Syndrome

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

INTRODUCTION AND OBJECTIVES

To 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.

METHODS

Study 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.

RESULTS

Total 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.

CONCLUSIONS

Current 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.

Lower paraoxonase 1 paraoxonase activity is associated with a worse prognosis in patients with non-ST-segment elevation myocardial infarction in long-term follow-up

BACKGROUND

Acute coronary syndrome (ACS) is one of the main manifestations of coronary artery disease, with a higher prevalence and worst prognosis. Oxidative stress is important in atherosclerosis and ACS, and paraoxonase 1 (PON1) is directly related to reducing the effects of oxidative stress on lipoproteins. The present study evaluated the prognostic value of PON1 activity in patients with non-ST-segment elevation ACS [non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina (UA)], included in the ERICO study.

METHODS

PON1 paraoxonase activity was determined in serum samples from 485 patients collected on admission. The prognostic value in the follow-up of up to 5 years was evaluated according to cutoff points established by tertiles. Kaplan-Meier curves and Cox regression were used for the analysis of all-cause mortality and cardiovascular mortality.

RESULTS

The sample consisted mainly of elderly patients with a high frequency of cardiovascular risk factors. At follow-up of up to 5 years, there were 126 deaths from all causes (80 deaths from CVD). The lowest tertile of PON1 paraoxonase activity was associated with a higher risk of death in patients with NSTEMI, but not in patients with UA.

CONCLUSION

PON1 paraoxonase activity has potential prognostic value in patients with NSTEMI.

Environmental Factors Modifying HDL Functionality

BACKGROUND

Currently, it has been recognized that High-Density Lipoproteins (HDL) functionality plays a much more essential role in protection from atherosclerosis than circulating HDL-cholesterol (HDL-C) levels per se. Cholesterol efflux from macrophages to HDL, cholesterol efflux capacity (CEC) has been shown to be a key metric of HDL functionality. Thus, quantitative assessment of CEC may be an important tool for the evaluation of HDL functionality, as improvement of HDL function may lead to a reduction of the risk for Cardiovascular disease (CVD).

INTRODUCTION

Although the cardioprotective action of HDLs is exerted mainly through their involvement in the reverse cholesterol transport (RCT) pathway, HDLs also have important anti-inflammatory, antioxidant, antiaggregatory and anticoagulant properties that contribute to their favorable cardiovascular effects. Certain genetic, pathophysiologic, disease states and environmental conditions may influence the cardioprotective effects of HDL either by inducing modifications in lipidome and/or protein composition or in the enzymes responsible for HDL metabolism. On the other hand, certain healthy habits or pharmacologic interventions may actually favorably affect HDL functionality.

METHOD

The present review discusses the effects of environmental factors, including obesity, smoking, alcohol consumption, dietary habits, various pharmacologic interventions, as well as aerobic exercise, on HDL functionality.

RESULT

Experimental and clinical studies or pharmacological interventions support the impact of these environmental factors in the modification of HDL functionality, although the mechanisms that are mediated are poorly understood.

CONCLUSION

Further research should be conducted to unreal the underlying mechanisms of these environmental factors and to identify new pharmacologic interventions, capable of enhancing CEC, improving HDL functionality and potentially improving cardiovascular risk.

High-density lipoprotein's vascular protective functions in metabolic and cardiovascular disease - could extracellular vesicles be at play?

High-density lipoprotein (HDL) is a circulating complex of lipids and proteins known primarily for its role in reverse cholesterol transport and consequent protection from atheroma. In spite of this, therapies aimed at increasing HDL concentration do not reduce the risk of cardiovascular disease (CVD), and as such focus has shifted towards other HDL functions protective of vascular health - including vasodilatory, anti-inflammatory, antioxidant and anti-thrombotic actions. It has been demonstrated that in disease states such as CVD and conditions of insulin resistance such as Type 2 diabetes mellitus (T2DM), HDL function is impaired owing to changes in the abundance and function of HDL-associated lipids and proteins, resulting in reduced vascular protection. However, the gold standard density ultracentrifugation technique used in the isolation of HDL also co-isolates extracellular vesicles (EVs). EVs are ubiquitous cell-derived particles with lipid bilayers that carry a number of lipids, proteins and DNA/RNA/miRNAs involved in cell-to-cell communication. EVs transfer their bioactive load through interaction with cell surface receptors, membrane fusion and endocytic pathways, and have been implicated in both cardiovascular and metabolic diseases - both as protective and pathogenic mediators. Given that studies using density ultracentrifugation to isolate HDL also co-isolate EVs, biological effects attributed to HDL may be confounded by EVs. We hypothesise that some of HDL's vascular protective functions in cardiovascular and metabolic disease may be mediated by EVs. Elucidating the contribution of EVs to HDL functions will provide better understanding of vascular protection and function in conditions of insulin resistance and potentially provide novel therapeutic targets for such diseases.

The role of the characteristics of exercise-based cardiac rehabilitation program in the improvement of lipid profile level: A systematic review and meta-analysis

BACKGROUND

The current study aimed to update prior systematic review and meta-analyses (SRMA) in order to determine the effects of supervised exercise-based cardiac rehabilitation (EBCR) and introduce a suitable exercise protocol for management of lipid profile abnormalities in patients with cardiovascular disease (CVD).

METHODS

PubMed, Scopus, and Web of Science databases were searched from 1980 to December 2018. All published, randomized controlled trials (RCTs) reporting the efficacy of supervised EBCR in patients with CVD and measuring at least 1 component of lipid profile were included. The quality of articles was assessed based on the Physiotherapy Evidence Database (PEDro) scale. Random effect model was used to calculate the effect size of post-intervention data.

RESULTS

Initially 774 RCTs were reviewed, 14 of them were included in the study. In comparison with the control group, supervised EBCR was associated with higher serum levels of high-density lipoprotein (HDL) [weight mean difference (WMD): 1.297; 95% confidence interval (CI): -1.620, 4.214] and lower serum level of low-density lipoprotein (LDL) (WMD: -7.797; 95%CI: -14.005, -1.588), total cholesterol (TC) (WMD: -11.029; 95%CI: -20.716, -1.342), and triglyceride (TG) (WMD: -14.602; 95%CI: -28.992, -0.212).

CONCLUSION

It seems that EBCR is correlated with an insignificant increase in HDL serum level and a significant decrease in LDL, TC, and TG serum levels. Considering subgroup analysis results, it is suggested that long duration, moderate exercise volume (EV), and combination of aerobic exercise (AE) and resistance exercise (RE) be used to improve HDL and TG serum levels. Short duration, high EV, and AE+RE seem to significantly reduce LDL serum level. Moreover, moderate EV is associated with a significant reduction in TC level.

HDL functions and their interaction in patients with ST elevation myocardial infarction: a case control study

Background

Recent studies emphasize the importance of HDL function over HDL cholesterol measurement, as an important risk for cardiovascular diseases (CVD). We compared the HDL function of patients with acute coronary syndrome (ACS) and healthy controls.

Methods

We measured cholesterol efflux capacity of HDL using THP-1 macrophages labelled with fluorescently tagged (BODIPY) cholesterol. PON1 activities toward paraoxon and phenyl acetate were assessed by spectrophotometric methods.

Results

We recruited 150 ACS patients and 110 controls. The HDL function of all patients during acute phase and at six month follow-up was measured. The mean age of the patients and controls was 51.7 and 43.6 years respectively. The mean HDL cholesterol/apolipoprotein A-I levels (ratio) of patients during acute phase, follow-up and of controls were 40.2 mg/dl/ 112.5 mg/dl (ratio = 0.36), 38.3 mg/dl/ 127.2 mg/dl (ratio = 0.30) and 45.4 mg/dl/ 142.1 mg/dl (ratio = 0.32) respectively. The cholesterol efflux capacity (CEC) of HDL was positively correlated with apolipoprotein A-I levels during acute phase (r = 0.19, p = 0.019), follow-up (r = 0.26, p = 0.007) and of controls (r = 0.3, p = 0.0012) but not with HDL-C levels (acute phase: r = 0.07, p = 0.47; follow-up: r = 0.1, p = 0.2; control: r = 0.02, p = 0.82). Higher levels of cholesterol efflux capacity, PON1 activity and apolipoprotein A-I were associated with lower odds of development of ACS. We also observed that low CEC is associated with higher odds of having ACS if PON1 activity of HDL is also low and vice versa.

Conclusion

ACS is associated with reduced HDL functions which improves at follow-up. The predicted probability of ACS depends upon individual HDL functions and the interactions between them.

Effects of exercise on HDL functionality

PURPOSE OF REVIEW

Low HDL-cholesterol (HDL-C) levels are a strong predictor of cardiovascular disease risk and can be improved with regular exercise. However, raising HDL-C levels pharmacologically has not shown convincing clinical benefits. Thus, research has recently focused on identifying therapies that improve HDL function, with exercise representing such a potential therapy. The purpose of this review is to summarize the effects of exercise interventions on HDL function.

RECENT FINDINGS

The effects of exercise and lifestyle interventions on the primary atheroprotective functions of HDL are reviewed, namely, cholesterol efflux, antioxidative, and anti-inflammatory properties. Differences in study design, study population, and assays are discussed to aid in the interpretation of the reviewed studies.

SUMMARY

There is mixed evidence that regular aerobic exercise improves cholesterol efflux capacity, with recent research suggesting an exercise dose threshold needs to be exceeded to produce beneficial effects. There is preliminary evidence that exercise improves the antioxidative and anti-inflammatory properties of HDL. Although exercise represents a potential therapeutic approach to improve HDL function, the heterogeneity and/or lack of findings warrants more and larger studies to determine what HDL function(s) are most responsive to regular exercise and what dose of exercise elicits the greatest improvements in HDL functionality.

Impact of a one-year lifestyle modification program on cholesterol efflux capacities in men with abdominal obesity and dyslipidemia

Cholesterol efflux capacities (CECs) are negatively associated with cardiovascular disease risk, irrespective of plasma high-density lipoprotein (HDL) cholesterol levels. Whether interventions targeting lifestyle improve HDL-CECs is unknown. Our objective was to determine whether improving dietary quality and increasing physical activity levels improves HDL-CECs in men with abdominal obesity and dyslipidemia. Our study sample included men (48 ± 8.5 yr) with an elevated waist circumference (≥90 cm) associated with dyslipidemia (triglycerides ≥1.69 and/or HDL cholesterol <1.03 mmol/l); 113 men completed a 1-yr intervention, consisting of a healthy eating and physical activity/exercise program, and 32 were included in a control group. An oral lipid tolerance test (OLTT) was performed in a subsample of 28 men who completed the intervention, and blood was collected every 2 h for 8 h. HDL-CECs were measured using [³H]cholesterol-labeled J774 macrophages and HepG2 hepatocytes. The lifestyle modification program led to an overall improvement in the cardiometabolic risk profile, increases in J774-HDL-CEC by 14.1% (+0.88 ± 1.09%, P < 0.0001), HepG2-HDL-CEC by 3.4% (+0.17 ± 0.75%, P = 0.01), and HDL cholesterol and apolipoprotein A-1 levels (13.5%, P < 0.0001 and 14.9%, P < 0.0001, respectively). J774-HDL-CECs and HepG2-HDL-CECs did not change in the control group. The best predictor for changes in HDL-CEC was apolipoprotein A-1 level. The lifestyle modification program also improved HDL-CEC response in postprandial lipemia during an OLTT. HDL-CEC did not change during the OLTT. Our results suggest that increasing physical activity levels and improving diet quality can have a positive impact on both HDL quantity and quality in men with abdominal obesity and dyslipidemia.