The effects of physical exercise on plasma prebeta-1 high-density lipoprotein

The Impact of Aerobic Exercise on HDL Quantity and Quality: A Narrative Review

High-density lipoproteins comprise roughly 25-30% of the circulating proteins involved in the transport of lipids in circulation. These particles differ in size and lipid composition. Recent evidence suggests that the quality of HDL particles (which depends on shape, size and the composition of proteins and lipids determining HDL functionality) may be more important than their quantity. The functionality of HDL is mirrored by its cholesterol efflux activity, as well as its antioxidant (including the protection of LDL against oxidation), anti-inflammatory and antithrombotic properties. The results of many studies and meta-analyses imply the beneficial impact of aerobic exercise on HDL-C levels. Physical activity was found to be usually associated with an increase in HDL cholesterol and a decrease in LDL cholesterol and triglycerides. Exercise, apart from inducing quantitative alterations in serum lipids, exerts a beneficial impact on HDL particle maturation, composition and functionality. The Physical Activity Guidelines Advisory Committee Report underlined the importance of establishing a program recommending exercises that enable attainment of maximal advantage at the lowest level of risk. The aim of this manuscript is to review the impact of different types of aerobic exercise (various intensities and durations) on the level and quality of HDL.

The effect of two types of diet on apoptosis indexes, lipid profile and histopathological outcome in acute kidney injury during exercise

Background

Exercise and some pre-AKI diets have been shown to improve injury, apoptosis, and lipid profile. In this study, the effect of two different diets along with exercise training on acute kidney injury (AKI) was investigated. 

Materials and methods

Laboratory rats were randomly divided into four groups of control, standard diet + exercise, exercise + calorie restriction (CR) and exercise + time restriction (TR). Each group was divided into two subgroups of AKI and no AKI. The animals received endurance training and diet regimens before AKI. Fasting blood glucose, serum creatinine, Bcl-2-associated X protein (Bax), B-cell lymphoma 2 (Bcl2) and histopathological outcome of renal tissue as well as serum lipid profile of animals were assessed 24 h after AKI. 

Results

The percentage of changes in renal Bcl2 and Bax after AKI in the group with previous exercise was lower than the group without previous exercise (p < 0.01). After induction of AKI, serum lipid profile changed in non-exercised rats (p < 0.001). Also, after injury, fasting blood glucose levels increased in non-exercised rats (p < 0.05). After injury, the start of both CR and TR diets during exercise caused less change in Bcl2 and Bax of non-exercised rats compared to exercised rats (p < 0.001). CR diet along with exercise improved lipid profile, and also CR diet along exercise decreased fasting blood glucose levels (p < 0.001). Also, both the CR and TR diets during exercise caused fewer changes in histopathological outcome after AKI.

Conclusion

Exercise alone decreased changes in apoptotic and histopathological indexes, fasting blood glucose, as well as lipid profile of rats after AKI. Reduction of apoptosis and improvement of histopathological outcome after AKI appeared more when CR and TR diets were commenced during exercise. The reduction of lipid profile changes was more pronounced in the group that received CR diet during exercise.

Effect of a Single Session of Tai Chi Chuan Practice on Glucose and Lipid Metabolism and Related Hormones

BACKGROUND

To examine the effect of Tai Chi Chuan (TCC) practice on glucose and lipid metabolism and related hormones in TCC practitioners.

METHODS

Twenty-one TCC practitioners and nineteen healthy controls were included in this study. Classical Yang's TCC was practiced by the TCC practitioners. The percentage changes in serum total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), serum glucose (SG), serum insulin, serum insulin level, homeostatic model assessment of insulin resistance (HOMA-IR), log(HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and serum endothelin-1 (ET-1) before and 30 min after resting or TCC practice were compared between healthy controls and TCC practitioners.

RESULTS

Before TCC or resting, the serum insulin level, HOMA-IR, and log(HOMA-IR) of the TCC practitioners were significantly lower than those of healthy subjects, whereas the QUICKI of the TCC practitioners was significantly higher than that of healthy subjects. Thirty min after TCC practice, the %TC, %HDL-C, %QUICKI, and %ET-1 were all significantly decreased, whereas the %SG, %serum insulin, and %HOMA-IR were significantly increased in the TCC group as compared to the control group 30 min after resting.

CONCLUSIONS

The serum glucose, insulin level and insulin resistance were enhanced, whereas the cholesterol, HDL-C and ET-1 levels were reduced 30 min after TCC practice. The mechanism underlying these effects of TCC 30 min after TCC is not clear yet.

The effect of curcumin and exercise rehabilitation on liver paraoxonase-1 and NF-kβ gene expression in the rat induced by forced drinking of ethanol

Aim of the study

Binge ethanol drinking causes liver damage and decreased paraoxonase-1 (PON-1) gene expression. On the other hand, regular physical activity and curcumin consumption as non-invasive interventions can have liver protective effects through enhancing antioxidant defense, and improving PON-1 and NF-kβ (nuclear factor kappa B) gene expression. The aim of this study was to investigate the interactive effect of exercise rehabilitation and curcumin consumption on hepatocyte damage as well as NF-kβ and PON-1 gene expression in rats.

Material and methods

Fifty-six male Wistar rats were randomly selected and equally divided into seven groups: dextrose-control (Dext-Con), ethanol-control (Eth-Con), ethanol-saline (Eth-sal), ethanol-DMSO (Eth-DMSO), ethanol-curcumin (Eth-Cur), ethanol-swimming training (Eth-SWT) and ethanol-SWT + curcumin (Eth-SWT + Cur). After four days of the binge drinking protocol followed by six days of quitting, the interventions of SWT and curcumin (50 mg/kg) were employed for 14 days. Afterwards, the rats’ liver tissues were collected and sent to the laboratory for biochemical assays.

Results

The interaction of SWT and curcumin caused an increase in PON-1 gene expression (p = 0.02). In addition, curcumin consumption (p = 0.003) and its interaction with SWT (p = 0.004) resulted in a reduction in NF-kβ gene expression. Also, liver tissue damage was observed in the Eth-Con group compared to other groups.

Conclusions

The combination of curcumin and SWT may be used to reduce the side effects of binge ethanol drinking and improve recovery in the quitting period.

Physical activity and sedentary behaviour in relation to cardiometabolic risk in children: cross-sectional findings from the Physical Activity and Nutrition in Children (PANIC) Study

Background

Lower levels of physical activity (PA) and sedentary behaviour (SB) have been associated with increased cardiometabolic risk among children. However, little is known about the independent and combined associations of PA and SB as well as different types of these behaviours with cardiometabolic risk in children. We therefore investigated these relationships among children.

Methods

The subjects were a population sample of 468 children 6–8 years of age. PA and SB were assessed by a questionnaire administered by parents and validated by a monitor combining heart rate and accelerometry measurements. We assessed body fat percentage, waist circumference, blood glucose, serum insulin, plasma lipids and lipoproteins and blood pressure and calculated a cardiometabolic risk score using population-specific Z-scores and a formula waist circumference + insulin + glucose + triglycerides - HDL cholesterol + mean of systolic and diastolic blood pressure. We analysed data using multivariate linear regression models.

Results

Total PA was inversely associated with the cardiometabolic risk score (β = -0.135, p = 0.004), body fat percentage (β = -0.155, p < 0.001), insulin (β = -0.099, p = 0.034), triglycerides (β = -0.166, p < 0.001), VLDL triglycerides (β = -0.230, p < 0.001), VLDL cholesterol (β = -0.168, p = 0.001), LDL cholesterol (β = -0.094, p = 0.046) and HDL triglycerides (β = -0.149, p = 0.004) and directly related to HDL cholesterol (β = 0.144, p = 0.002) adjusted for age and gender. Unstructured PA was inversely associated with the cardiometabolic risk score (β = -0.123, p = 0.010), body fat percentage (β = -0.099, p = 0.027), insulin (β = -0.108, p = 0.021), triglycerides (β = -0.144, p = 0.002), VLDL triglycerides (β = -0.233, p < 0.001) and VLDL cholesterol (β = -0.199, p < 0.001) and directly related to HDL cholesterol (β = 0.126, p = 0.008). Watching TV and videos was directly related to the cardiometabolic risk score (β = 0.135, p = 0.003), body fat percentage (β = 0.090, p = 0.039), waist circumference (β = 0.097, p = 0.033) and systolic blood pressure (β = 0.096, p = 0.039). Resting was directly associated with the cardiometabolic risk score (β = 0.092, p = 0.049), triglycerides (β = 0.131, p = 0.005), VLDL triglycerides (β = 0.134, p = 0.009), VLDL cholesterol (β = 0.147, p = 0.004) and LDL cholesterol (β = 0.105, p = 0.023). Other types of PA and SB had less consistent associations with cardiometabolic risk factors.

Conclusions

The results of our study emphasise increasing total and unstructured PA and decreasing watching TV and videos and other sedentary behaviours to reduce cardiometabolic risk among children.

Trial registration

ClinicalTrials.gov Identifier: NCT01803776.

FAMP, a novel apoA-I mimetic peptide, suppresses aortic plaque formation through promotion of biological HDL function in ApoE-deficient mice

Background

Apolipoprotein (apo) A‐I is a major high‐density lipoprotein (HDL) protein that causes cholesterol efflux from peripheral cells through the ATP‐binding cassette transporter A1 (ABCA1), thus generating HDL and reversing the macrophage foam cell phenotype. Pre‐β₁ HDL is the smallest subfraction of HDL, which is believed to represent newly formed HDL, and it is the most active acceptor of free cholesterol. Furthermore it has a possible protective function against cardiovascular disease (CVD). We developed a novel apoA‐I mimetic peptide without phospholipids (Fukuoka University ApoA‐I Mimetic Peptide, FAMP).

Methods and Results

FAMP type 5 (FAMP5) had a high capacity for cholesterol efflux from A172 cells and mouse and human macrophages in vitro, and the efflux was mainly dependent on ABCA1 transporter. Incubation of FAMP5 with human HDL or whole plasma generated small HDL particles, and charged apoA‐I‐rich particles migrated as pre‐β HDL on agarose gel electrophoresis. Sixteen weeks of treatment with FAMP5 significantly suppressed aortic plaque formation (scrambled FAMP, 31.3±8.9% versus high‐dose FAMP5, 16.2±5.0%; P<0.01) and plasma C‐reactive protein and monocyte chemoattractant protein‐1 in apoE‐deficient mice fed a high‐fat diet. In addition, it significantly enhanced HDL‐mediated cholesterol efflux capacity from the mice.

Conclusions

A newly developed apoA‐I mimetic peptide, FAMP, has an antiatherosclerotic effect through the enhancement of the biological function of HDL. FAMP may have significant atheroprotective potential and prove to be a new therapeutic tool for CVD.

Lipid profile, apolipoprotein A-I and oxidative stress in professional footballers, sedentary individuals, and their relatives

OBJECTIVE

To evaluate whether lipid profile (LP), apolipoprotein A-1 (apo A-I) and malondialdehyde (MDA) have any relationship with physical exercise by comparing the groups of footballers (FG) with sedentary individuals (CG) and their relatives (RFG and RCG).

SUBJECTS AND METHODS

Twenty individuals from FG and CG, 60 from RFG, and 57 from RCG were studied.

RESULTS

FG showed lower levels of total cholesterol (119.5 ± 37.9 mg/dL), LDL-cholesterol fraction (53.6 ± 30.3), apo A-I (116.7 ± 11.9), and higher level of HDL-cholesterol fraction (HDLc) (49.7 ± 8.5) compared to RFG (148.3 ± 36.9, P = 0.02; 82.4 ± 37.7, P < 0.01; 124.6 ± 10.2, P = 0.03; and 42.7 ± 7.7, P < 0.01; respectively). Moreover, FG had reduced levels of MDA (101.0 ± 77.0 ng/mL) compared to CG (290.0 ± 341.0, P = 0.03) and RFG (209.9 ± 197.5, P = 0.04).

CONCLUSIONS

These results suggest an association between physical exercise and lower levels of MDA in FG. Physical activity seems to promote beneficial effects on the LP regardless of the genetic influence considering HDLc levels.

Voluntary exercise increases cholesterol efflux but not macrophage reverse cholesterol transport in vivo in mice

Physical exercise beneficially impacts on the plasma lipoprotein profile as well as on the incidence of cardiovascular events and is therefore recommended in primary and secondary prevention strategies against atherosclerotic cardiovascular disease. However, the underlying mechanisms of the protective effect of exercise remain largely unknown. Therefore, the present study tested the hypothesis that voluntary exercise in mice impacts on cholesterol efflux and in vivo reverse cholesterol transport (RCT). After two weeks of voluntary wheel running (average 10.1 ± 1.4 km/day) plasma triglycerides were lower (p < 0.05), while otherwise lipid and lipoprotein levels did not change. Macrophage cholesterol efflux towards plasma was significantly increased in running (n = 8) compared to sedentary (n = 6) mice (14.93 ± 1.40 vs. 12.33 ± 2.60%, p < 0.05). In addition, fecal excretion of bile acids (3.86 ± 0.50 vs. 2.90 ± 0.51 nmol/d, p = 0.001) and neutral sterols (2.75 ± 0.43 vs. 1.94 ± 0.22 nmol/d, p < 0.01) was significantly higher in running mice. However, RCT from macrophages to feces remained essentially unchanged in running mice compared with sedentary controls (bile acids: 3.2 ± 1.0 vs. 2.9 ± 1.1 % of injected dose, n.s.; neutral sterols: 1.4 ± 0.7 vs. 1.1 ± 0.5 % injected dose, n.s.). Judged by the plasma lathosterol to cholesterol ratio, endogenous cholesterol synthesis was increased in exercising mice (0.15 ± 0.03 vs. 0.11 ± 0.02, p < 0.05), while the hepatic mRNA expression of key transporters for biliary cholesterol (Abcg5/g8, Sr-bI) as well as bile acid (Abcb11) and phospholipd (Abcb4) excretion did not change. These data indicate that the beneficial effects of exercise on cardiovascular health include increased cholesterol efflux, but do not extend to other components of RCT. The increased fecal cholesterol excretion observed in running mice is likely explained by higher endogenous cholesterol synthesis, however, it does not reflect increased RCT in the face of unchanged expression of key transporters for biliary sterol secretion.

High pre-beta1 HDL concentrations and low lecithin: cholesterol acyltransferase activities are strong positive risk markers for ischemic heart disease and independent of HDL-cholesterol

BACKGROUND

We hypothesized that patients with high HDL-cholesterol (HDL-C) and ischemic heart disease (IHD) may have dysfunctional HDL or unrecognized nonconventional risk factors.

METHODS

Individuals with IHD (Copenhagen University Hospital) and either high HDL-C (n = 53; women >or=735 mg/L; men >or=619 mg/L) or low HDL-C (n = 42; women <or=387 mg/L; men <or=341 mg/L) were compared with individuals without IHD (Copenhagen City Heart Study) matched by age, sex, and HDL-C concentrations (n = 110). All participants had concentrations within reference intervals for LDL-C (<1600 mg/L) and triglyceride (<1500 mg/L), and none were treated with lipid-lowering medications. Pre-beta(1) HDL and phospholipid transfer protein concentrations were measured by using commercial kits and lecithin:cholesterol acyltransferase (LCAT) activity by using a proteoliposome cholesterol esterification assay.

RESULTS

Pre-beta(1) HDL concentrations were 2-fold higher in individuals with IHD vs no IHD in both the high [63 (5.7) vs 35 (2.3) mg/L; P < 0.0001] and low HDL-C [49 (5.0) vs 27 (1.5) mg/L; P = 0.001] groups. Low LCAT activity was also associated with IHD in the high [95.2 (6.7) vs 123.0 (5.3) micromol x L(-1) x h(-1); P = 0.002] and low [93.4 (8.3) vs 113.5 (4.9) micromol x L(-1) . h(-1); P = 0.03] HDL-C groups. ROC curves for pre-beta(1) HDL in the high-HDL-C groups yielded an area under the curve of 0.71 (95% CI: 0.61-0.81) for predicting IHD, which increased to 0.92 (0.87-0.97) when LCAT was included. Similar results were obtained for low HDL-C groups. An inverse correlation between LCAT activity and pre-beta(1) HDL was observed (r(2) = 0.30; P < 0.0001) in IHD participants, which was stronger in the low HDL-C group (r(2) = 0.56; P < 0.0001).

CONCLUSIONS

IHD was associated with high pre-beta(1) HDL concentrations and low LCAT levels, yielding correct classification in more than 90% of the IHD cases for which both were measured, thus making pre-beta(1) HDL concentration and LCAT activity level potentially useful diagnostic markers for cardiovascular disease.

Endurance training enhances ABCA1 expression in rat small intestine

The purpose of this study was to investigate liver and intestinal ABCA1 expression and plasma HDL-C level in response to treadmill-running training in rats. Twenty adult Wistar male rats (17-18 weeks old, 300-322 g) were divided into control (n = 10) and Training (n = 10) groups. Training group trained at 25 m/min (0% grade) for 60 min/day, 5 days/week for 12 weeks. Rats were killed 48 h after the last session of training. The intestinal and liver ABCA1 mRNA expression was found to be significantly higher in trained compared to control group (P < 0.006 and P < 0.024, respectively). Intestine and liver ATP concentrations remained unchanged. Plasma HDL-C, HDL2-C, Apo A-1, pre-beta HDL-C concentration, LCAT activity, TC/HDL-C and LDL-C/HDL-C ratio significantly increased in trained group (P < 0.01, P < 0.006, P < 0.001, P < 0.001 P < 0.067, P < 0.02, and P < 0.03, respectively). However, other lipoprotein concentrations were unchanged. In conclusion, we found that endurance training induced significant elevation in plasma HDL-C and HDL2-C concentrations, accompanied by higher plasma Apo A-1, pre-beta HDL-C concentrations, LCAT activity and ABCA1 mRNA expressions in rat intestine, and liver.

Low high-density lipoprotein cholesterol: an important consideration in coronary heart disease risk assessment

PURPOSE OF REVIEW

One aim is to summarize evidence from observational studies and clinical trials evaluating the inverse relationship between high-density lipoprotein and coronary heart disease. Other aims are to explore the mechanisms underlying the reported cardioprotective effects of high-density lipoprotein and to evaluate therapeutic modalities to increase high-density lipoprotein levels and functionality.

RECENT FINDINGS

In addition to reverse cholesterol transport, recent data suggest that high-density lipoprotein possesses antioxidant, anti-inflammatory and fibrinolytic properties and the inverse relationship between high-density lipoprotein cholesterol and coronary heart disease is most evident with associated elevations in low-density lipoprotein cholesterol and triglyceride. Recent data suggest, however, that even after low-density lipoprotein cholesterol is sufficiently reduced, residual coronary heart disease risk persists with low high-density lipoprotein cholesterol. The excess death rate reported with the high-density lipoprotein cholesterol raising drug torcetrapib appears to have been the result of an off-target effect of the drug, rather than an effect attributable to cholesteryl ester transfer protein inhibition.

SUMMARY

Low high-density lipoprotein cholesterol remains an important consideration in coronary heart disease risk assessment, however several issues remain unresolved. They include the extent to which low high-density lipoprotein cholesterol in the absence of other risk factors augments risk, the relationship between high-density lipoprotein functionality and levels of high-density lipoprotein cholesterol and whether and to what extent improving these parameters independently offsets coronary heart disease risk.

Aerobic exercise training improves the role of high-density lipoprotein antioxidant and reduces plasma lipid peroxidation in type 2 diabetes mellitus

In this study, we analyzed the effect of aerobic exercise training (AET) and of a single bout of exercise on plasma oxidative stress and on antioxidant defenses in type 2 diabetes mellitus (DM) and in healthy control subjects (C). DM and C did not differ regarding triglycerides, high-density lipoprotein cholesterol (HDL-c), insulin, and HOMA index at baseline and after AET. To measure the lag time for low-density lipoprotein (LDL) oxidation (LAG) and the maximal rate of conjugated diene formation (MCD), participants' plasma HDL(2) and HDL(3) were incubated with LDL from pooled healthy donors' plasma. In the presence of HDL(3), both LAG and MCD were similar in C and DM, but only in DM did AET improve LAG and reduce MCD. In the presence of HDL(2), the lower baseline LAG in DM equaled C after AET. MCD was unchanged in DM after AET, but was lower than C only after AET. Furthermore, after AET plasma thiobarbituric acid-reactive substances were reduced only in DM subjects. Despite not modifying the total plasma antioxidant status and serum paraoxonase-1 activity in both groups, AET lowered the plasma lipid peroxides, corrected the HDL(2), and improved the HDL(3) antioxidant efficiency in DM independent of the changes in blood glucose, insulin, and plasma HDL concentration and composition.

Treadmill exercise enhances ABCA1 expression in rat liver

ATP-binding cassette transporters (ABCs) belong to a large family and include 49 mammalian transmembrane transporters that transfer a variety of substrates across the lipid bilayers in an energy-dependent manner. ABCA1 is a member of this family which plays a crucial role in plasma HDL-C remodeling. The purpose of this study was to investigate liver ABCA1 expression and plasma HDL level in response to treadmill running program in rats. Ten adult Wistar male rats (12-14weeks old, 200-220g) were used for this study. Animals were divided into control (Con, n=5) and Training (TR, n=5) groups. Training group was given exercise on a motor-driven treadmill at 25m/min (0% grade) for 90min/day, 5 days/week for 6 weeks. Rats were sacrificed 24h after the last session of exercise portion of the liver was excised, immediately washed in ice-cold saline, and frozen in liquid nitrogen for extraction of ABCA1 mRNA. Plasma was collected for HDL-C, LDL, TC, TG, and VLDL-C measurements. Liver ABCA1 mRNA expression was significantly (P<0.001) higher in trained rats compared to control rats. Plasma HDL-C, LCAT, pre-beta-HDL concentrations were significantly higher (P<0.01, P<0.001, P<0.028, respectively) in trained rats at the end of treadmill exercise. However, plasma lipids, other lipoproteins and TC/HDL and LDL/HDL ratio were unchanged. In conclusion, a treadmill running-induced elevated plasma HDL-C concentration was accompanied with a higher liver ABCA1 mRNA expression and increased in LCAT and pre-beta-HDL levels.

Plant sterols combined with exercise for the treatment of hypercholesterolemia: overview of independent and synergistic mechanisms of action

At present, dyslipidemia is most commonly treated with lipid-altering pharmacological therapies. However, safety concerns regarding the use of these agents have prompted the need for safe and efficacious nonpharmacological lipid-altering interventions. One such natural therapy is the combination of plant sterols and endurance training. This combination lifestyle intervention has been shown to decrease total cholesterol, low-density lipoprotein (LDL) cholesterol and triglyceride concentrations while increasing high-density lipoprotein (HDL) cholesterol concentrations. However, the mechanisms that underlie these positive lipid alterations have yet to be clarified. Thus, the purpose of this review is to evaluate individual effects of plant sterols and exercise training on lipid levels while attempting to elucidate the possible independent and synergistic mechanisms of action responsible for these modulations. Results reveal that plant sterols decrease both total and LDL cholesterol levels by reducing exogenous cholesterol absorption by way of cholesterol displacement in the intestinal lumen. Additionally, the intestinal membrane transport proteins, ABCG5, ABCG8, as well as NPC1L1, have also been implicated in plant sterol-mediated cholesterol lowering. Conversely, exercise decreases triglyceride levels by reducing hepatic very low-density lipoprotein secretion and increasing skeletal lipoprotein lipase activity. In addition, endurance training was shown to increase HDL cholesterol levels by way of HDL subfraction alterations, in conjunction with changing reverse cholesterol transport enzyme activities. Moreover, plant sterols and exercise may work synergistically to alter lipid levels by modulating lipoprotein transport, composition, release and metabolism. In sum, the present review lends further insight as to the metabolic benefits of adopting a healthy lifestyle, including plant sterols and endurance training, in the treatment of dyslipidemia.

Effect of plant sterols and endurance training on LDL particle size and distribution in previously sedentary hypercholesterolemic adults

BACKGROUND

Plant sterols and exercise favourably alter lipid profiles in a way that protect against future coronary heart disease (CHD). However, their effects on other indicators of CHD risk, such as LDL particle size, still need further clarification.

OBJECTIVE

This study examined the effect of plant sterols, exercise, and the combination of plant sterols and exercise, on LDL particle size and distribution in previously sedentary, hypercholesterolemic adults.

DESIGN

In an 8-week, placebo-controlled, parallel-arm clinical trial, 84 subjects were randomized to one of four intervention groups: (1) combination of sterols and exercise, (2) exercise, (3) sterol, or (4) control.

RESULTS

Exercise significantly (P < 0.05) reduced post-treatment LDL peak particle size from 255 to 253 A. Additionally, exercise significantly (P < 0.05) decreased the proportion of large LDL particles within plasma. Sterol supplementation significantly (P < 0.05) decreased the estimated cholesterol concentrations within small, medium, and large LDL particles by 13.4, 13.5, and 14.4%, respectively, yet had no effect on the distribution of cholesterol among various LDL particle sizes. Furthermore, decreased body weight post-training was associated with increased cholesterol in small LDL particles (r = -0.52, P < 0.0001). Decrease in body fat percent (BF%) post-training was associated with increased cholesterol concentrations in small LDL particles (r = -0.29, P < 0.01).

CONCLUSION

On the basis of modulating LDL electrophoretic characteristics, the present study demonstrates that plant sterols have no effect on CHD risk, while short-term exercise may potentially increase CHD risk by decreasing LDL peak particle size.

SPONSORSHIP

This study was sponsored by The Heart and Stroke Foundation of Canada.

Apolipoprotein A1 genotype affects the change in high density lipoprotein cholesterol subfractions with exercise training

High density lipoprotein cholesterol (HDL-C) is a primary risk factor for cardiovascular disease. Apolipoprotein A-1 (apoA1) is the major HDL-associated apolipoprotein. The -75G/A single nucleotide polymorphism (SNP) in the apolipoprotein A1 gene (APOA1) promoter has been reported to be associated with HDL-C concentrations as well as HDL-C response to dietary changes in polyunsaturated fat intake. We examined the effect of this APOA1 SNP on exercise-induced changes in HDL subfraction distribution. From a cohort of healthy normolipidemic adults who volunteered for 6 months of supervised aerobic exercise, 75 subjects were genotyped for the -75G/A SNP. Of these, 53 subjects were G homozygotes (G/G) and 22 were A carriers (A/G and A/A). HDL subfractions were measured by nuclear magnetic resonance (NMR) spectroscopy by adding categories HDL-C 1+2 for the small subfraction, and HDL-C 3+4+5 for the large. The change in total HDL-C after exercise was 0.8+/-7.2 mg/dL (+1.7%), and was not statistically significant. HDL subfraction amounts also did not significantly change with exercise training in the total cohort or in G homozygotes or A carriers. The amount of the large HDL subfraction increased in the G homozygotes and decreased in the A carriers (mean+/-S.E.M., 1.8+/-6.6 mg/dL versus -6.1+/-2.3 mg/dL, p<0.0005). In contrast, the amount of the small HDL subfraction decreased in G homozygotes and increased in A carriers (-1.3+/-6.6 mg/dL versus 4.7+/-1.2 mg/dL, p<0.005). These results show that genetic variation at the APOA1 gene promoter is associated with HDL subfraction redistribution resulting from exercise training.

Enhanced cholesterol efflux promotion in well-trained soccer players

It is widely accepted that aerobic physical activity is associated with a less atherogenic lipid and lipoprotein profile and, consequently, with a reduced cardiovascular risk. Both cross-sectional studies and prospective-interventional trials show that the most frequent modification observed consists of a slight but significant increase in high-density lipoprotein cholesterol (HDL-C) levels. Nevertheless, only few studies made an attempt to elucidate if this quantitative modification was accompanied by an improvement in any of HDL antiatherogenic functions. The purpose of this study was to evaluate the main steps of reverse cholesterol transport, the best known antiatherogenic function performed by HDL, in a group of well-trained soccer players (n = 35) in comparison to sedentary controls (n = 15). Average HDL-C levels were 12.5% higher in the sportsmen, in large part because of greater HDL2-C concentration. No statistically significant differences were observed in the other lipid- and lipoprotein-related parameters. The capacity to promote cholesterol efflux from Fu5AH cells was significantly higher in the soccer players than in the control individuals (20.5% +/- 0.4% v 15.9% +/- 1.2%, respectively, P < .001). However, lecithin:cholesterol acyltransferase (LCAT; 2.6 +/- 0.9 v 1.4 +/- 0.3%/mL.h, respectively) and cholesteryl ester transfer protein (CETP; 69.5 +/- 8.3 v 62.7 +/- 14.8%/mL.h, respectively) activities did not reach statistically significant difference between both groups. Correlation analysis showed that cholesterol efflux induced by serum samples was directly related to HDL-C (r = 0.59, P < .001), HDL2-C (r = 0.37, P < .01), and lipoprotein (Lp)A-I (r = 0.44, P < .05). On the other hand, negative correlations were observed with waist/hip ratio (r = -0.36, P < .05), low-density lipoprotein cholesterol (LDL-C; r = -0.33, P < .05), apolipoprotein B (apo B; r = -0.42, P < .05), and LpA-I;A-II (r = -0.51, P < .005). In conclusion, the well-known cardioprotective benefit of regular exercise could be based, at least in part, on a less atherogenic lipid and lipoprotein profile and an enhanced cellular cholesterol efflux.

Physical Fitness and Reverse Cholesterol Transport

BACKGROUND

Physical exercise is associated with a decreased risk of cardiovascular disease, which may be partly caused by the effect of exercise on the lipoprotein profile. The most consistent effect of exercise on lipoprotein metabolism is an increase in high-density lipoprotein (HDL).

METHODS AND RESULTS

Parameters of reverse cholesterol transport (RCT) in 25 endurance-trained male athletes were compared with 33 age-matched males enjoying an active lifestyle. VO2max was higher in athletes than in controls (53.4+/-1.2 versus 38.8+/-1.0 mL/min per kg; P<0.01). The following differences in parameters of RCT were found: (1) plasma HDL cholesterol and apoA-I levels were higher in athletes compared with controls (1.7+/-0.1 versus 1.4+/-0.1 mmol/L; P<0.001; and 145+/-2 versus 128+/-3 mg/dL; P<0.001, respectively). Both correlated with VO2max up to the value of 51 mL/min per kg; (2) prebeta1-HDL was higher in athletes than in controls (54+/-4 versus 37+/-3 microg/mL; P<0.001) and correlated positively with VO2max; (3) lecithin cholesterol: acyltransferase activity was higher in athletes (29.8+/-1.2 versus 24.2+/-1.4 nmol/microL per hour; P<0.005); and (4) the capacity of plasma to promote cholesterol efflux from macrophages was higher in athletes (18.8%+/-0.8% versus 16.2%+/-0.3%; P<0.03).

CONCLUSIONS

The likely reason for higher HDL concentration in physically fit people is increased formation of HDL from apoA-I and cellular lipids.

Physical activity and its effects on lipids

Physical activity is an important component of weight control, and is widely recommended to prevent and treat obesity-related complications such as diabetes and coronary heart disease (CHD). Although the cardiovascular benefits of increased physical activity are likely multifactorial, much of the attention has been focused on the known high-density lipoprotein (HDL) cholesterol-raising properties of regular physical activity. Physical activity, however, can also reliably lower triglycerides and favorably affect both low-density lipoprotein (LDL) and HDL particle sizes. Limited data on resistance exercise suggest that this type of physical activity may reduce LDL cholesterol. Although these lipid effects are modest and variable, they are likely to be particularly important in reducing the morbidity and mortality from CHD on a population level, and may be especially important in patients with atherogenic dyslipidemia.

The effect of physical exercise on reverse cholesterol transport

High-density lipoproteins (HDL) are recognized for their role in coronary artery disease (CAD) risk reduction. Plasma HDL plays a pivotal role in the reverse cholesterol transport (RCT) process. Physical exercise is well recognized as a modality that affects HDL metabolism. The purpose of this discussion is to describe the effects of physical exercise on RCT.