Life style change and reverse cholesterol transport in obese women

High Density Lipoproteins: Metabolism, Function, and Therapeutic Potential

High Density Lipoproteins (HDLs) have long been considered as “good cholesterol,” beneficial to the whole body and, in particular, to cardio-vascular health. However, HDLs are complex particles that undergoes dynamic remodeling through interactions with various enzymes and tissues throughout their life cycle, making the complete understanding of its functions and roles more complicated than initially expected. In this review, we explore the novel understanding of HDLs' behavior in health and disease as a multifaceted class of lipoprotein, with different size subclasses, molecular composition, receptor interactions, and functionality. Further, we report on emergent HDL-based therapeutics tested in small and larger scale clinical trials and their mixed successes.

Exercise intervention alters HDL subclass distribution and function in obese women

BACKGROUND

Obesity is associated with a change in high-density lipoprotein (HDL) function and subclass. Exercise training reduces cardiovascular risk in obese patients. We aimed to explore the effect of an exercise training stimulus on HDL functionality and subclass in obese women.

METHODS

Thirty-two obese black South African women were randomly assigned to exercise (combined aerobic and resistance exercise) or control (no exercise) conditions for 12-weeks. Pre- and post-testing included venous blood sampling for analysis of lipid profile and HDL functionality, by measuring cellular cholesterol efflux capacity, reduction in endothelial vascular cell adhesion molecule (VCAM) expression (anti-inflammatory function), paraoxonase (PON) (antioxidative function) and platelet activating factor acetylhydrolase (PAF-AH) activities (anti-thrombotic function). PON-1 and PAF-AH expression were determined in serum and in isolated HDL using Western blotting. Levels of large, intermediate and small HDL subclasses were measured using the Lipoprint® system.

RESULTS

Exercise training resulted in a decrease in body mass index (- 1.0 ± 0.5% vs + 1.2 ± 0.6%, p = 0.010), PON activity (- 8.7 ± 2.4% vs + 1.1 ± 3.0%, p = 0.021), PAF-AH serum expression (- 22.1 ± 8.0% vs + 16.9 ± 9.8, p = 0.002), and the distribution of small HDL subclasses (- 10.1 ± 5.4% vs + 15.7 ± 6.6%, p = 0.004) compared to controls. Exercise did not alter HDL cellular cholesterol efflux capacity and anti-inflammatory function.

CONCLUSIONS

These results demonstrate the potential for exercise training to modify HDL subclass distribution and HDL function in obese women.

TRIAL REGISTRATION

Clinical trials number: PACTR201711002789113 .

Beyond Statins: Emerging Evidence for HDL-Increasing Therapies and Diet in Treating Cardiovascular Disease

Coronary heart disease continues to be the leading cause of death in the United States. Current attempts to treat atherosclerosis and coronary artery disease often involve pharmaceutical and surgical treatments. While these treatments are successful in managing the pain from coronary heart disease, they do little to prevent or stop it. There are a number of clinical strategies that are currently being researched to treat atherosclerosis through HDL-increasing therapies. These clinical studies have shown positive effects through nutritional intervention, exercise, stress reduction, and tobacco and alcohol cessation. These treatment options are explored in greater detail, including their potential to halt and even reverse atherosclerosis. The results from these recent studies and how they relate to the mechanism of reverse cholesterol transport are also critically examined. Reverse cholesterol transport is a multistep process resulting in the net movement of cholesterol from peripheral tissues back to the liver via the plasma. The mechanism of reverse cholesterol transport is also further explored in this review.

Effects of Increasing Exercise Intensity and Dose on Multiple Measures of HDL (High-Density Lipoprotein) Function

OBJECTIVE

Measures of HDL (high-density lipoprotein) function are associated with cardiovascular disease. However, the effects of regular exercise on these measures is largely unknown. Thus, we examined the effects of different doses of exercise on 3 measures of HDL function in 2 randomized clinical exercise trials.

APPROACH AND RESULTS

Radiolabeled and boron dipyrromethene difluoride-labeled cholesterol efflux capacity and HDL-apoA-I (apolipoprotein A-I) exchange were assessed before and after 6 months of exercise training in 2 cohorts: STRRIDE-PD (Studies of Targeted Risk Reduction Interventions through Defined Exercise, in individuals with Pre-Diabetes; n=106) and E-MECHANIC (Examination of Mechanisms of exercise-induced weight compensation; n=90). STRRIDE-PD participants completed 1 of 4 exercise interventions differing in amount and intensity. E-MECHANIC participants were randomized into 1 of 2 exercise groups (8 or 20 kcal/kg per week) or a control group. HDL-C significantly increased in the high-amount/vigorous-intensity group (3±5 mg/dL; P=0.02) of STRRIDE-PD, whereas no changes in HDL-C were observed in E-MECHANIC. In STRRIDE-PD, global radiolabeled efflux capacity significantly increased 6.2% (SEM, 0.06) in the high-amount/vigorous-intensity group compared with all other STRRIDE-PD groups (range, -2.4 to -8.4%; SEM, 0.06). In E-MECHANIC, non-ABCA1 (ATP-binding cassette transporter A1) radiolabeled efflux significantly increased 5.7% (95% CI, 1.2-10.2%) in the 20 kcal/kg per week group compared with the control group, with no change in the 8 kcal/kg per week group (2.6%; 95% CI, -1.4 to 6.7%). This association was attenuated when adjusting for change in HDL-C. Exercise training did not affect BODIPY-labeled cholesterol efflux capacity or HDL-apoA-I exchange in either study.

CONCLUSIONS

Regular prolonged vigorous exercise improves some but not all measures of HDL function. Future studies are warranted to investigate whether the effects of exercise on cardiovascular disease are mediated in part by improving HDL function.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifiers: NCT00962962 and NCT01264406.

Changes in High-Density Lipoprotein Cholesterol Efflux Capacity After Bariatric Surgery Are Procedure Dependent

OBJECTIVE

High-density lipoprotein cholesterol efflux capacity (CEC) is inversely associated with incident cardiovascular events, independent of high-density lipoprotein cholesterol. Obesity is often characterized by impaired high-density lipoprotein function. However, the effects of different bariatric surgical techniques on CEC have not been compared. This study sought to determine the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on CEC.

APPROACH AND RESULTS

We prospectively studied severely obese, nondiabetic, premenopausal Hispanic women not using lipid medications undergoing RYGB (n=31) or SG (n=36). Subjects were examined before and at 6 and 12 months after surgery. There were no differences in baseline characteristics between surgical groups. Preoperative CEC correlated most strongly with Apo A1 (apolipoprotein A1) concentration but did not correlate with body mass index, waist:hip, high-sensitivity C-reactive protein, or measures of insulin resistance. After 6 months, SG produced superior response in high-density lipoprotein cholesterol and Apo A1 quantity, as well as global and non-ABCA1 (ATP-binding cassette transporter A1)-mediated CEC (P=0.048, P=0.018, respectively) versus RYGB. In multivariable regression models, only procedure type was predictive of changes in CEC (P=0.05). At 12 months after SG, CEC was equivalent to that of normal body mass index control subjects, whereas it remained impaired after RYGB.

CONCLUSIONS

SG and RYGB produce similar weight loss, but contrasting effects on CEC. These findings may be relevant in discussions about the type of procedure that is most appropriate for a particular obese patient. Further study of the mechanisms underlying these changes may lead to improved understanding of the factors governing CEC and potential therapeutic interventions to maximally reduce cardiovascular disease risk in both obese and nonobese patients.

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

AIMS

We evaluated whether exercised-based cardiac rehabilitation (CR) can ameliorate the HDL function, i.e., cholesterol efflux capacity (CEC) and paraoxonase-1 activity in patients with acute coronary syndrome (ACS).

METHODS

This study is a retrospective analysis of stored serum from patients with ACS following successful percutaneous coronary intervention. The CEC, measured by a cell-based ex vivo assay using apolipoprotein B-depleted serum and ³H-cholesterol labeled macrophages and arylesterase activity (AREA) at the onset or early phase of ACS, and the follow-up periods were compared between 69 patients who completed the five-month outpatient CR program (CR group) and 15 patients who did not participate and/or dropped out from CR program (non-CR group).

RESULTS

Apolipoprotein A-I (apoA-I) and CEC significantly increased by 4.0% and 9.4%, respectively, in the CR group, whereas HDL-cholesterol and AREA were not changed during the follow-up periods in both groups. Among CR patients, the CEC significantly increased, irrespective of the different statin treatment, while HDL-cholesterol and apoA-I significantly increased in patients treated with rosuvastatin or pitavastatin. Although CEC and AREA were significantly correlated each other, there is a discordance between CEC and AREA for their correlations with other biomarkers. Both CEC and AREA were significantly correlated with apoA-I rather than HDL-cholesterol. Changes in CEC and those in AREA were significantly correlated with those in apoA-I (rho=0.328, p=0.002, and rho=0.428, p＜0.0001, respectively) greater than those in HDL-cholesterol (rho=0.312, p= 0.0042,and rho=0.343, p=0.003, respectively).

CONCLUSIONS

CR can improve HDL function, and it is beneficial for secondary prevention.

Effects of aerobic exercise on lipids and lipoproteins

Dyslipidemia is the risk of cardiovascular disease, and their relationship is clear. Lowering serum cholesterol can reduce the risk of coronary heart disease. At present, the main treatment is taking medicine, however, drug treatment has its limitations. Exercise not only has a positive effect on individuals with dyslipidemia, but can also help improve lipids profile. This review is intending to provide information on the effects of exercise training on both tranditional lipids, for example, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides and new lipids and lipoproteins such as non-high-density lipoprotein cholesterol, and postprandial lipoprotein. The mechanisms of aerobic exercise on lipids and lipoproteins are also briefly described.

Impact of Lifestyle Intervention on HDL-Induced eNOS Activation and Cholesterol Efflux Capacity in Obese Adolescent

Background. Endothelial dysfunction occurs in obese children and adolescent and is regarded as a key step in the development of atherosclerosis. Important components for the development of endothelial dysfunction are reduced activity of endothelial nitric oxide synthase (eNOS) and an increase in cholesterol deposition in the vessel wall, due to reduced reverse cholesterol transport (RCT) activity. High density lipoprotein (HDL) exhibits antiatherosclerotic properties including modulation of eNOS activity and cholesterol efflux capacity. Lifestyle intervention programs can modify endothelial dysfunction in obese adolescents, but their impact on HDL-mediated eNOS activation and RCT is unknown so far. Methods. Obese adolescents (15 ± 1 years, BMI > 35 kg/m²) where randomized either to an intervention group (IG, n = 8; restricted diet and exercise) or to a usual care group (UC, n = 8). At the beginning and after 10 months of treatment HDL-mediated eNOS phosphorylation and cholesterol efflux capacity were evaluated. Results. Ten months of treatment resulted in a substantial weight loss (−31%), an improvement of endothelial function, and an increase in HDL-mediated eNOS-Ser¹¹⁷⁷ phosphorylation and RCT. A correlation between change in eNOS-Ser¹¹⁷⁷ phosphorylation or RCT and change in endothelial function was noted. Conclusion. A structured lifestyle intervention program improves antiatherosclerotic HDL functions, thereby positively influencing endothelial function.

The therapeutic efficacy of intensive medical therapy in ameliorating high-density lipoprotein dysfunction in subjects with type two diabetes

BACKGROUND

To determine whether 12 months of intensive medical therapy (IMT) improves HDL functionality parameters in subjects with type II diabetes (T2D).

METHODS

Retrospective, randomized, and controlled 12-month IMT intervention trial that enrolled 13-subjects with T2D (age 51- years, fasting glucose 147 mg/dL, body mass index [BMI] 36.5 kg/m(2)) and nine healthy control (46-years, fasting glucose 90 mg/dL, BMI 26.5 kg/m2). Subjects with T2D underwent IMT and HDL functionality measures (pro-inflammatory index of high-density lipoprotein (pHDL)), paraoxonase one (PON1), ceruloplasmin (Cp), and myeloperoxidase (MPO) activity were performed on samples at baseline and at 12-months following IMT.

RESULTS

At baseline, pHDL index was significantly higher in subjects with T2D (p < 0.001) and apolipoprotein A-1 levels were significantly lower (p = 0.013) vs.

CONTROLS

After 12-months, there was a trend for improved pHDL activity (p = 0.083), as indicated by intent-to-treat analysis, but when the non-adherent subject was omitted (per-protocol), significant attenuations in pHDL activity (p = 0.040) were noted; Δ pHDL activity at 12-months was associated with Δ weight (r = 0.62, p = 0.032) and Δ fasting glucose (r = 0.65, p = 0.022). Moreover, PON1 activity significantly improved (p < 0.001). The aforementioned occurred in association with improvements in inflammatory markers (i.e., C-reactive protein & tumor necrosis factor), hemoglobin A1C, fasting glucose, triglycerides, high-density lipoprotein levels and adipokines.

CONCLUSION

IMT ameliorates pHDL index and significantly improves anti-oxidative function, as measured by PON1. Improvements in weight and fasting glucose mediated the decrease in pHDL index. Pharmacological aids and lifestyle modification are required to improve cardiovascular risk factors, subsequent mortality risk, and promote T2D remission. Application of either form of therapy alone may only have relatively miniscule effects on the aforementioned factors, in relation to the aggregate.

Exercise-mediated changes in high-density lipoprotein: impact on form and function

The goal of this systematic review was to assess the current understanding of the effects of exercise intervention on high-density lipoprotein (HDL) cholesterol (HDL-C) and changes in HDL function as well as modification of these effects by genomic factors. The reviewed studies demonstrate that exercise has modest effects on HDL-C with limited data suggesting an effect on HDL function. Genetic polymorphisms in proteins associated with HDL metabolism play a role in modifying the HDL-C response to exercise and possibly its function. Exercise as an intervention for patients at risk for cardiovascular events can lead to small improvements in HDL-C and potential changes in HDL function. There is an important modifier effect of genetics in determining these changes.

A single 1-h session of moderate-intensity aerobic exercise does not modify lipids and lipoproteins in normolipidemic obese women

The purpose of this study was to quantify the effects of a single session of aerobic exercise on lipids and lipoproteins in women who were sedentary and obese. Women (n = 12) who were premenopausal, sedentary, and obese (body mass index, 30–40 kg·m–2; waist circumference > 88 cm) completed exercise and control trials in a randomly assigned order. Exercise consisted of a single session of treadmill walking at 70% maximum oxygen uptake until 500 kcal were expended, and the control protocol consisted of 60 min of seated rest. Fasting blood samples were collected immediately prior to, 24 h, and 48 h following the exercise and control sessions and analyzed for triglyceride, total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), HDL2-C, and HDL3-C concentrations, and mean LDL, HDL2, and HDL3particle size and cholesterol distributions. A 2 × 3 (trial × time) ANOVA with repeated measures revealed no significant (p > 0.05) changes in the lipid and lipoprotein variables 24 and 48 h following exercise. In contrast to previously published data in lean men and women, a single session of treadmill exercise at 70% maximum oxygen uptake that expended 500 kcal was insufficient to modify lipids and lipoproteins in women who were sedentary, normolipidemic, and obese.

The effect of the addition of resistance training to a dietary education intervention on apolipoproteins and diet quality in overweight and obese older adults

Objectives

The aim of the study was to examine the additive effect of resistance training (RT) to a dietary education (DE) intervention on emerging coronary heart disease (CHD) risk factors, concentration of apolipoproteins B (apoB) and A-I (apoA-I), and Dietary Approaches to Stop Hypertension (DASH) Diet Index scores in overweight and obese older adults.

Patients and methods

This was an ancillary study of a randomized clinical trial held in the Fall of 2008 at the University of Rhode Island. Participants were overweight or obese subjects (mean body mass index [BMI] of 31.7 kg/m²) randomized into two groups, one participating in DE only (n = 12) and the other participating in DE plus RT (DERT) (n = 15). The intervention involved all subjects participating in 30 minutes of DE per week for 10 weeks. Subjects in the DERT group participated in an additional 40 minutes of RT three times per week for 10 weeks. Measurements taken were anthropometric (height, weight, waist circumference, and body composition using the BOD POD^® [Body Composition System, v 2.14; Life Measurement Instruments, Concord, CA]), clinical (blood pressure), and biochemical (lipid profile and apoB and apoA-I concentrations), and the DASH Diet Index was used to measure diet quality.

Results

27 subjects (11 males, 16 females), with a mean age of 66.6 ± 4.3 years, were included in analyses. The DERT subjects had significantly better triacylglycerol and apoB concentrations and DASH Diet Index scores than the DE subjects post-intervention. Improvements were seen within the DE group in energy intake, fat-free mass, and systolic blood pressure and within the DERT group in body weight, percentage of body fat, BMI, diastolic blood pressure, and oxidized low-density lipoprotein (all P < 0.05).

Conclusion

The addition of RT effectively reduced CHD risk factors, body composition, and diet quality in overweight and obese older adults; DERT was more effective than DE alone in improving DASH Diet Index scores and lowering apoB concentrations but was not more effective in increasing apoA-I concentrations. Future research is needed to determine if apolipoproteins are superior to lipoprotein cholesterol concentrations in predicting CHD risk.