High density lipoprotein subfractions, apolipoprotein A-I containing lipoproteins, lipoprotein (a), and cholesterol ester transfer protein activity in alcoholic women before and after ethanol withdrawal

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.

Low-dose ethanol intake prevents high-fat diet-induced adverse cardiovascular events in mice

This study aimed to clarify whether low-dose ethanol intake could prevent high-fat diet-induced adverse effects on cardiomyocytes in mice.

Polyacrylamide gradient gel electrophoresis of lipoprotein subclasses

High-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins are heterogeneous cholesterol-containing particles that differ in their metabolism, environmental interactions, and association with disease. Several protocols use polyacrylamide gradient gel electrophoresis (GGE) to separate these major lipoproteins into known subclasses. This article provides a brief history of the discovery of lipoprotein heterogeneity and an overview of relevant lipoprotein metabolism, highlighting the importance of the subclasses in the context of their metabolic origins, fates, and clinical implications. Various techniques using polyacrylamide GGE to assess HDL and LDL heterogeneity are described, and how the genetic and environmental determinations of HDL and LDL affect lipoprotein size heterogeneity and the implications for cardiovascular disease are outlined.

Genetic variation in the hepatic lipase gene and the risk of coronary heart disease among US diabetic men: potential interaction with obesity

AIMS/HYPOTHESIS

The -514 C to T polymorphism of the hepatic lipase gene (LIPC) has been associated with lowered LIPC activity and elevated HDL-cholesterol concentrations. Previous findings on the association of this polymorphism with the risk of CHD are inconsistent. Moreover, data on this association among diabetic patients are limited. We investigated the association of the LIPC polymorphism with CHD risk among US diabetic men and evaluated whether this association was modified by adiposity status.

SUBJECTS AND METHODS

The case group consisted of 220 diabetic men who were recruited from the Health Professionals Follow-up Study (years 1986-2000) and were free of cardiovascular disease at baseline, but subsequently developed CHD. A total of 641 diabetic men from the same study but without cardiovascular disease constituted the control group.

RESULTS

No overall association between the LIPC polymorphism and CHD risk was observed. However, we did observe a significant interaction between this polymorphism and BMI in association with CHD risk. Among obese men, after adjustment for age, duration of diabetes and major lifestyle factors, the CT or TT genotype was associated with an increased CHD risk compared with the CC genotype (odds ratio [OR] 2.52, 95% CI 1.08-5.90); the corresponding ORs (95% CI) were 0.99 (0.58, 1.69) for overweight men (25< or =BMI <30 kg/m(2)) and 0.37 (0.17, 0.79) for lean men (BMI <25 kg/m(2)) (p for interaction 0.001). Stratified analyses by waist circumference (tertiles) showed a similar pattern of interaction (adjusted p for interaction 0.023).

CONCLUSION/INTERPRETATION

These data suggest that obesity may modify the association between the LIPC C(-514)T polymorphism and CHD risk among diabetic men.

Effect of acute and chronic moderate red or white wine consumption on fasted and postprandial lipemia in the rat

The effects of acute and chronic (10 wk) red or white wine consumption on fasted and postprandial lipemia in the rat model are reported. Fasted rats, in the acute study, were loaded intragastrically with 5 ml of an olive oil emulsion (30% w/v) in the presence or absence of wine (8% v/v ethanol), and either mesenteric lymph or blood was collected 3 h postprandially. Animals in the chronic study received either red or white wine in drinking water for a period of 10 wk (3% v/v ethanol). Blood samples were collected from animals in either the fasted state or after fat-wine loading. Postprandially, wine delayed gastric emptying, reduced lymph triacylglycerol (TAG) secretion concomitantly with increased number and decreased chylomicron (CM) size, and increased plasma TAG and CM concentrations. Phospholipid and cholesterol contents of CM, but not very-low-density lipoprotein (VLDL), were increased, indicating enhanced liver bile secretion; however, a significant increase in plasma VLDL concentration was observed. In the chronic study, a wine-fat load resulted in increased high-density lipoprotein (HDL) cholesterol concentration and less pronounced postprandial hypertriglyceridemia and hyperchylomicronemia. In the fasted state, plasma TAG and total apolipoprotein B concentrations were not modified in these animals, and an increase in HDL and a decrease in low-density lipoprotein (LDL)/HDL cholesterol ratios were observed. No liver function or intestinal lipid absorption impairment was observed. In conclusion, unlike binge drinking, chronic moderate wine consumption appears to have a cardioprotective effect in the fasted state, an effect attenuated by the observed temporary postprandial hyperchylomicronemia and hypertriglyceridemia resulting from a direct effect of alcohol on CM size and number.

Effects of ethanol on lipids and atherosclerosis

Moderate alcohol consumption is associated with an increase in plasma high density lipoprotein (HDL) cholesterol concentration and a decrease in low density lipoprotein (LDL) cholesterol concentration. Changes in the concentration and composition of lipoproteins are estimated to account for more than half of alcohol's protective effect for coronary heart disease. Alcohol intake also affects plasma proteins involved in lipoprotein metabolism: cholesteryl ester transfer protein, phospholipid transfer protein, lecithin:cholesterol acyltransferase, lipoprotein lipase, hepatic lipase, and phospholipases. In addition, alcohol intake may result in acetaldehyde modification of apolipoproteins. Furthermore, "abnormal" lipids, phosphatidylethanol and fatty acid ethyl esters are formed in the presence of ethanol and are associated with lipoproteins in plasma. Ethanol and ethanol-induced modifications of lipids may modulate the effects of lipoproteins on the cells in the arterial wall. The molecular mechanisms involved in these processes are complex, requiring further study to better understand the specific effects of ethanol in the pathogenesis of atherosclerosis. This review discusses the effects of ethanol on lipoproteins and lipoprotein metabolism, as well as the novel effects of lipoproteins on vascular wall cells.

Alcohol consumption and its relation to cardiovascular risk factors in Germany

OBJECTIVE

To analyse the association of alcohol consumption and blood lipids, haemostatic factors, and homocysteine in German adults by gender and age groups.

DESIGN

Cross-sectional population-based survey.

SETTING

Data from the German National Health Interview and Examination Survey 1998, representative for age, gender, community size, and federal state.

SUBJECTS

From a sample of 7124 Germans between 18 and 79 y old, 2420 women and 2365 men were selected. Only individuals who were not currently receiving medical treatment or did not have disorders related to cardiovascular disease were selected for this study.

RESULTS

Using analyses of variance, mean blood levels of total cholesterol, HDL cholesterol, HDL/total cholesterol ratio, total glycerides, fibrinogen, antithrombin III, and homocysteine adjusted for age, socioeconomic status, East/West Germany residence, body mass index, tobacco use, sports activity, and coffee consumption, if appropriate are presented by alcohol consumption groups (0, >0-10, >10-20, >20-30 and >30 g/day). The HDL/total cholesterol ratio increased with higher alcohol groups up to 10-20 g/day (+15%) for women and >30 g/day (+18%) for men, showing the strongest rise among men aged 55-79 y. Fibrinogen decreased with higher alcohol groups up to 10-20 g/day for women and 20-30 g/day for men. Among women, homocysteine levels showed a U-shaped curve with a minimum of 8.49 mmol/l at 10-20 g alcohol/day (-8%, reference: nondrinking), whereas an inverse association was observed for men.

CONCLUSIONS

Moderate alcohol consumption is associated with favourable levels of several cardiovascular risk factors. The most favourable cardiovascular risk factor profile among women was observed among those drinking 10-20 g alcohol/day. Beneficial effects seem to be more pronounced among older men.

Effect of acute and chronic moderate alcohol consumption on fasted and postprandial lipemia in the rat

Effects of acute and chronic alcohol intake on fasted and postprandial lipemia in the rat model are reported. In the acute study, fasted rats are loaded with a 30% w/w olive oil emulsion with or without 8% alcohol in the form of ethanol, beer or whisky. After 3 h, either mesenteric lymph or blood is collected and the TAG-rich lipoprotein fractions are isolated. In the chronic study, animals received, for a period of 10 weeks, 3% alcohol in drinking water in the form of ethanol, beer or whisky. Blood samples were collected from animals in either the fasted state or after being loaded with the fat load as described above. Alcohol ingestion along with a fat load increases the number (increased net apoB48 secretion) and reduces the size (reduced TAG/apoB48 ratio) of CM secreted into the mesenteric lymph duct. It also delays gastric emptying, reduces trans-enterocyte TAG flux rates and increases plasma concentrations of TAG, cholesterol and CM. Similar conditions also results in increased total phospholipid and cholesterol content of CM but not of VLDL, indicating an enhanced liver bile secretion into the gut; however, a significant increase in plasma VLDL concentration is observed. Unlike the acute study, an alcohol-fat load in animals put on chronic alcohol intake results in increased HDL cholesterol concentrations and less pronounced postprandial hypertriglyceridemia and hypercholesterolemia but not hyperchylomicronemia. In the fasted state, plasma TAG and total apoB concentrations are not modified in these animals, and an increase in HDL and a decrease in total and LDL cholesterol concentrations are observed. No liver function impairment is observed following the 10-week period of chronic alcohol intake. In conclusion, unlike binge drinking, chronic moderate alcohol consumption appears to have a cardioprotective effect in the fasted state, an effect attenuated by the observed temporary postprandial hyperchylomicronemia and hypertriglyceridemia resulting from a direct effect of alcohol on CM size and number.

Cardiovascular manifestations of substance abuse: part 2: alcohol, amphetamines, heroin, cannabis, and caffeine

The abuse of alcohol is associated with chronic cardiomyopathy, hypertension, and arrhythmia. Abstinence or using alcohol in moderation can reverse these cardiovascular problems. Alcohol is also distinguished among the substances of abuse by having possible protective effects against coronary artery disease and stroke when used in moderate amounts. Amphetamines (eg, speed, ice, ecstasy) have many of the cardiovascular toxicities seen with cocaine, including acute and chronic cardiovascular diseases. Heroin and other opiates can cause arrhythmias and noncardiac pulmonary edema, and may reduce cardiac output. Cardiovascular problems are less common with cannabis (marijuana) than with opiates, but major cognitive disorders may be seen with its chronic use. It is still controversial whether caffeine can cause hypertension and coronary artery disease, and questions have been raised about its safety in patients with heart failure and arrhythmia.

Serum lipoprotein(a) concentrations and alcohol consumption in hypertension: possible relevance for cardiovascular damage

OBJECTIVES

To evaluate the relationships between alcohol intake and serum lipoprotein(a) [Lp(a)], a powerful predictor of organ damage, in patients with essential hypertension with a wide range of alcohol intake, and to investigate whether the association between alcohol intake and serum Lp(a) concentrations occurs over the entire spectrum of apo(a) phenotypes.

DESIGN

Cross-sectional study of a case series.

SETTING

University medical centre.

PATIENTS

Four hundred and two patients with untreated essential hypertension recruited at a hypertension clinic.

MAIN OUTCOME MEASURES

Serum Lp(a) concentrations, apo(a) isoforms, alcohol consumption, smoking habits and cardiovascular status.

RESULTS

No difference in Lp(a) concentrations was observed between teetotalers and occasional drinkers. Light drinkers (1-20 g/day ethanol), moderate drinkers (21-50 g/day), and heavy drinkers (> 50 g/day) had, respectively, 21, 26 and 57% lower median Lp(a) concentrations than teetotalers and occasional drinkers. Similar findings were obtained when male and female patients were analysed separately. Log Lp(a) concentrations were inversely and independently correlated with alcohol consumption in both men and women with hypertension. The frequency distributions of apo(a) isoforms and liver function parameters were comparable across the different alcohol intake groups. Patients with evidence of cardiovascular damage had greater concentrations of serum Lp(a) and higher frequency of low-molecular weight apo(a) isoforms as compared with patients without such evidence.

CONCLUSIONS

Serum Lp(a) is inversely and dose-dependently related with alcohol intake in patients with hypertension, and this relationship is independent of the size distribution of apo(a) isoforms. Reduction of Lp(a) concentrations by regular consumption of alcohol might favourably affect the atherosclerotic risk profile of patients with hypertension and thereby decrease cardiovascular morbidity.

Effect of alcohol on lipids and lipoproteins in relation to atherosclerosis

Several studies indicate that light-to-moderate alcohol consumption is associated with a low prevalence of coronary heart disease. An increase in high-density lipoprotein (HDL) cholesterol is associated with alcohol intake and appears to account for approximately half of alcohol's cardioprotective effect. In addition to changes in the concentration and composition of lipoproteins, alcohol consumption may alter the activities of plasma proteins and enzymes involved in lipoprotein metabolism: cholesteryl ester transfer protein, phospholipid transfer protein, lecithin:cholesterol acyltransferase, lipoprotein lipase, hepatic lipase, paraoxonase-1 and phospholipases. Alcohol intake also results in modifications of lipoprotein particles: low sialic acid content in apolipoprotein components of lipoprotein particles (e.g., HDL apo E and apo J) and acetaldehyde modification of apolipoproteins. In addition, "abnormal" lipids, phosphatidylethanol, and fatty acid ethyl esters formed in the presence of ethanol are associated with lipoproteins in plasma. The effects of lipoproteins on the vascular wall cells (endothelial cells, smooth muscle cells, and monocyte/macrophages) may be modulated by ethanol and the alterations further enhanced by modified lipids. The present review discusses the effects of alcohol on lipoproteins in cholesterol transport, as well as the novel effects of lipoproteins on vascular wall cells.

Dose-dependent inverse relationship between alcohol consumption and serum Lp(a) levels in black African males

Serum or plasma levels of Lp(a) vary widely between individuals and are higher in Africans and their descendants compared with white persons. In whites, high serum levels of Lp(a) are associated with the premature development of atherosclerosis. In both ethnic groups, serum Lp(a) levels are highly genetically determined and only a few environmental or physiological factors, like testosterone or estrogen, have been shown to lower serum Lp(a) levels. In whites, alcohol consumption is associated with lower serum Lp(a) levels. However, the mechanism underlying this association and whether it holds true for blacks is not known. To address these questions, we analyzed serum Lp(a) levels in 333 middle-aged males of African descent from the Seychelles Islands (Indian Ocean). In addition, we analyzed the size of the apo(a) isoforms and the serum levels of albumin and sex hormones in a subset of 279 subjects. Serum Lp(a) levels were similar in teetotalers (median, 32.5 mg/dL; n=42) and occasional drinkers (median, 34.1 mg/dL; n=112). In contrast, individuals consuming 10 to 80 g of ethanol/d (n=83) and heavy drinkers (>80 g of ethanol/d, n=96) had a 9% and 32% lower median Lp(a) level than teetotalers, respectively (P=0.01). The size distribution of the apo(a) isoforms and the mean serum levels of albumin, estradiol, and luteinizing hormone were similar in teetotalers and occasional drinkers compared with moderate and heavy drinkers. These latter 2 groups had lower serum levels of testosterone and sex hormone-binding globulin. These data indicate that alcohol intake is associated in a dose-dependent manner with lower serum Lp(a) levels in males of African descent and that this association is not related to the size of the apo(a) isoforms, to the synthetic function of the liver, or to sex hormone biochemical status.

Moderate drinking and cardiovascular health

Moderate alcohol consumption (1-2 drinks a day) can be beneficial in reducing the risk of coronary artery disease. This article focuses on cellular and molecular mechanisms underlying the beneficial effect of moderate drinking, including increased plasma high-density lipoprotein levels, changes in cellular signaling, reduction in platelet function, stimulation of fibrinolysis, and reduction in ischemia-reperfusion injury. While moderate drinking may be protective against coronary artery disease for some individuals, populations such as pregnant women and individuals who are about to operate motor vehicles or heavy machinery should not drink alcoholic beverages. People with family histories of alcoholism should exercise extreme caution in their decision to drink.

Alcohol and lipids

Alcoholic fatty liver and hyperlipemia result from the interaction of ethanol and its oxidation products with hepatic lipid metabolism. An early target of ethanol toxicity is mitochondrial fatty acid oxidation. Acetaldehyde and reactive oxygen species have been incriminated in the pathogenesis of the mitochondrial injury. Microsomal changes offset deleterious accumulation of fatty acids, leading to enhanced formation of triacylglycerols, which are partly secreted into the plasma and partly accumulate in the liver. However, this compensatory mechanism fades with progression of the liver injury, whereas the production of toxic metabolites increases, exacerbating the lesions and promoting fibrogenesis. The early presence of these changes confers to the fatty liver a worse prognosis than previously thought. Alcoholic hyperlipemia results primarily from increased hepatic secretion of very-low-density lipoprotein and secondarily from impairment in the removal of triacylglycerol-rich lipoproteins from the plasma. Hyperlipemia tends to disappear because of enhanced lipolytic activity and aggravation of the liver injury. With moderate alcohol consumption, the increase in high-density lipoprotein becomes the predominant feature. Its mechanism is multifactorial (increased hepatic secretion and increased extrahepatic formation as well as decreased removal) and explains part of the enhanced cholesterol transport from tissues to bile. These changes contribute to, but do not fully account for, the effects on atherosclerosis and/or coronary heart disease attributed to moderate drinking.

Medical risks for women who drink alcohol

OBJECTIVE

To summarize for clinicians recent epidemiologic evidence regarding medical risks of alcohol use for women.

METHODS

MEDLINE and PsychINFO, 1990 through 1996, were searched using key words "women" or "woman," and "alcohol." MEDLINE was also searched for other specific topics and authors from 1980 through 1996. Data were extracted and reviewed regarding levels of alcohol consumption associated with mortality, cardiovascular disease, alcohol-related liver disease, injury, osteoporosis, neurologic symptoms, psychiatric comorbidity, fetal alcohol syndrome, spontaneous abortion, infertility, menstrual symptoms, breast cancer, and gynecologic malignancies. Gender-specific data from cohort studies of general population or large clinical samples are primarily reviewed.

MAIN RESULTS

Women develop many alcohol-related medical problems at lower levels of consumption than men, probably reflecting women's lower total body water, gender differences in alcohol metabolism, and effects of alcohol on postmenopausal estrogen levels. Mortality and breast cancer are increased in women who report drinking more than two drinks daily. Higher levels of alcohol consumption by women are associated with increased menstrual symptoms, hypertension, and stroke. Women who drink heavily also appear to have increased infertility and spontaneous abortion. Adverse fetal effects occur after variable amounts of alcohol consumption, making any alcohol use during pregnancy potentially harmful.

CONCLUSIONS

In general, advising nonpregnant women who drink alcohol to have fewer than two drinks daily is strongly supported by the epidemiologic literature, although specific recommendations for a particular woman should depend on her medical history and risk factors.

A controlled trial of the effects of pattern of alcohol intake on serum lipid levels in regular drinkers

To determine whether the effects of drinking pattern (predominantly weekend versus daily drinking) have differential effects on serum lipids, 55 healthy male drinkers were recruited on the basis of a regular alcohol intake, 210-500 ml absolute alcohol/week (approximately 3-6 standard drinks/day), with more than 60% consumed as beer. Fourteen subjects were categorised as predominantly weekend drinkers, while 41 subjects regularly drank on a daily basis. After maintenance of their drinking pattern during a 4-week familiarisation, subjects were randomised to either consume low alcohol beer (0.9%, v/v) only, or to maintain their usual drinking habit consuming full-strength beer (5%, v/v) for the next 4 weeks. They then switched to full-strength or low alcohol beer, respectively, for a further 4 weeks. Their drinking pattern remained constant during the study. In both weekend and daily drinkers, a reduction in alcohol intake (i.e. from 387 ml/week to 88 ml/week for weekend drinkers and from 418 ml/week to 95 ml/week for daily drinkers, respectively, P < 0.001) resulted in a similar 0.12 mmol/l fall in HDL-C (P < 0.01) with a concomitant significant fall in both apolipoproteins A-I and A-II. In daily drinkers total cholesterol fell by 0.28 mmol/l (P < 0.001) and triglyceride by 0.22 mmol/l (P < 0.01) with a reduction in alcohol intake, but no change in LDL-C was seen. In contrast, weekend drinkers total cholesterol was unchanged while triglyceride decreased by 0.26 mmol/l (P < 0.05) and LDL-C increased by 0.25 mmol/l (P < 0.01). Lp(a) increased with a reduction in alcohol intake in both daily (9.1 U/l, P < 0.05) and weekend drinkers (27.6 U/l, P = 0.07). Previous reports of a more atherogenic lipid profile with episodic versus regular daily drinking were not confirmed in this study and potentially favourable effects of alcohol to increase HDL-C and decrease Lp(a) were shown to be independent of drinking pattern in these moderate to heavy drinkers.

Non-pharmacological modification of cardiac risk factors: part 3. Smoking cessation and alcohol consumption

Smoking cessation (SC) is probably the single most important risk factor modification for both primary and secondary prevention of cardiovascular disease. Interventions to stop smoking are highly cost effective. SC produces reductions in mortality and morbidity that generally outweigh any increase in risk due to weight gain, unless the gain is so great that it is accompanied by adverse changes in blood pressure, lipid profile or glucose tolerance. There is clear evidence that SC improves the lipid profile, decreases thrombotic tendency, reduces vascular endothelial damage and improves insulin sensitivity. Epidemiological studies consistently demonstrate a reduced risk of developing coronary heart disease (CHD) with moderate alcohol consumption (showing protection at < or = 2 drinks per day), but an increased risk at higher alcohol consumption levels. Potential mediators of these cardioprotective effects include an increase in high-density cholesterol (HDL-C), decreased clotting propensity, enhanced insulin sensitivity and glucose tolerance, and a possible lowering of blood pressure at low consumption levels in women. Alcohol consumption may not, however, compensate for the large increase in risk produced by smoking. Whereas moderate alcohol consumption slightly reduces the risk of death between the ages of 35 and 69 years, cigarette smoking approximately doubles the risk.

Retinoids inhibit primary cynomolgus monkey hepatocyte lipoprotein(a) levels

Elevated plasma lipoprotein(a) [Lp(a)] independently contributes to a variety of vascular diseases; consequentially, factors that modulate its levels are of interest. Since Lp(a) is produced by a disulfide linkage between apolipoprotein(a) [apo(a)] and apolipoproteinB-100 (apoB-100) of low density lipoprotein (LDL) on the hepatocyte surface, modulation of either particle may be useful in lowering Lp(a). Using primary cynomolgus monkey hepatocyte cultures that endogenously express apo(a) and apoB-100, we showed that all-trans (retinol, retinal, retinoic acid) and 9-cis (retinal, retinoic acid) retinoids lower Lp(a) accumulation in the cell media, with the 9-cis derivatives being > 10-fold more potent than the all-trans stereoisomers. Lp(a) Towering was related to decreases in apo(a) and its cognate transcript, but not to apoB-100. These results demonstrate that retinoids lower Lp(a) levels by decreasing apo(a) through its cognate mRNA.

Associations of age, adiposity, menopause, and alcohol intake with low-density lipoprotein subclasses

We used nondenaturing polyacrylamide gradient gel electrophoresis to examine the associations of age, adiposity, menopause, and alcohol intake with LDL subclasses in 355 individuals. The absorbency of protein stain was used as an index of mass concentrations at intervals of 0.05 nm within seven LDL subclasses: LDL-IVB (22.0 to 23.2 nm), LDL-IVA (23.3 to 24.1 nm), LDL-IIIB (24.2 to 24.6 nm), LDL-IIIA (24.7 to 25.5 nm), LDL-II (25.5 to 26.4 nm), LDL-I (26.0 to 28.5 nm), and intermediate-size lipoproteins (ISL, 28.0 to 32.0 nm). Age and alcohol intake were obtained from questionnaires, and body mass index was computed from clinic measurements of weight and height. In adult men, body mass index correlated positively with LDL-III, and alcohol intake correlated positively with larger LDL-I. Age was positively correlated with LDL-IIIA and ISL in both men and women and with LDL-IIIB and LDL-II in women. Postmenopausal women had higher LDL-IIIA, LDL-II, and ISL than both premenopausal and premenarchal females. Adult males, > or = 18 years old, had higher levels of LDL-IIIA and LDL-II than younger males. Adjustment for fasting plasma triglyceride levels eliminated the significant associations between age and LDL-IIIA in both men and women and between age and LDL-II in women. Partial correlation analyses showed that reductions in the LDL peak diameter associated with increasing age, male sexual maturation, menopause, and adiposity are attributable to increases in the LDL-IIIA subclass. Thus, densitometric measurements of protein-stained gradient gels reveal specific relationships between LDL subclasses and age, adiposity, and alcohol intake beyond those identified by the LDL peak or average diameter.

Higher high density lipoprotein cholesterol associated with moderate alcohol consumption is not related to altered plasma lecithin:cholesterol acyltransferase and lipid transfer protein activity levels

Lecithin:cholesterol acyltransferase (LCAT), cholesteryl ester transfer protein (CETP) and phospholipid transfer protein (PLTP) are important factors involved in HDL metabolism. Altered plasma activity levels of these factors could play a role in the increase in high density lipoprotein (HDL) cholesterol associated with moderate alcohol consumption. We measured plasma LCAT, CETP and PLTP activities with exogenous substrate assays, as well as lipoproteins and HDL lipids in 6 alcohol-abstaining men, 18 matched men who used < or = 1 and 18 men who used > or = 1 alcohol-containing drinks per day. Plasma cholesterol and triglycerides were similar in the three groups. HDL total cholesterol, HDL cholesteryl ester, HDL free cholesterol and HDL triglycerides were higher in the alcohol drinkers compared to the abstainers (all P < 0.05). No differences in plasma LCAT, CETP and PLTP activity levels were observed between the three groups. Analysis of covariance also demonstrated that the use of alcohol was associated with higher HDL cholesterol (P < 0.04), whereas plasma LCAT, CETP and PLTP activity levels were not related to alcohol consumption. Furthermore, HDL cholesteryl ester was positively associated with LCAT activity (P < 0.001), PLTP activity (P < 0.01) and alcohol intake (P < 0.04) and negatively with plasma triglycerides (P < 0.001) and CETP activity (P < 0.03); indicating that alcohol influenced HDL cholesteryl ester independently from these biochemical parameters. The higher HDL cholesterol associated with moderate alcohol consumption is, therefore, unlikely to be caused by and effect on plasma LCAT, CETP or PLTP activity levels.

Opposite effects of cholesteryl ester transfer protein and phospholipid transfer protein on the size distribution of plasma high density lipoproteins. Physiological relevance in alcoholic patients

The aim of the present study was to investigate the role of the cholesteryl ester transfer protein (CETP) and the phospholipid transfer protein (PLTP) in determining the size distribution of high density lipoproteins (HDL) in human plasma. Whereas both purified CETP and PLTP preparations were able to promote the size redistribution of isolated HDL3, CETP favored the emergence of small HDL, while PLTP induced the formation of both small and large conversion products. When the total plasma lipoprotein fractions isolated from nine distinct subjects were incubated for 24 h at 37 degrees C with either purified PLTP or purified CETP, significant alterations in the relative proportions of the five distinct plasma HDL subpopulations, i.e., HDL2b (9.71-12.90 nm), HDL2a (8.77-9.71 nm), HDL3a (8.17-8.77 nm), HDL3b (7.76-8.17 nm), and HDL3c (7.21-7. 76 nm) were also observed. PLTP induced a significant increase in the relative abundance of HDL2b (8.66 +/- 2.34% versus 7.87 +/- 1. 83% in controls; p < 0.01) and a significant decrease in the relative abundance of HDL3a (32.76 +/- 3.42% versus 37.87 +/- 2.62% in controls; p < 0.05). In contrast, CETP significantly reduced the relative proportion of HDL2a (33.03 +/- 2.53% versus 37.56 +/- 6.43% in controls; p < 0.01) but significantly increased the relative proportion of both HDL3b (21.36 +/- 6.97% versus 15.58 +/- 7.75% in controls; p < 0.01) and HDL3c (3.21 +/- 4.84% versus 1.13 +/- 0.56% in controls; p < 0.05). Finally, in order to assess further the physiological relevance of in vitro observations, CETP activity, PLTP activity, and HDL size distribution were determined in plasmas from 33 alcoholic patients entering a cessation program. Alcohol withdrawal was associated with (i) a significant increase in plasma CETP activity (173.5 +/- 70.5%/h/ml before versus 223.2 +/- 69. 3%/h/ml after alcohol withdrawal, p = 0.0007), (ii) a significant reduction in plasma PLTP activity (473.9 +/- 203.7%/h/ml before versus 312.7 +/- 148.4%/h/ml after alcohol withdrawal, p = 0.0001), and (iii) a significant shift of large HDL2b and HDL2a toward small HDL3b and HDL3c. On the one hand, changes in plasma CETP activity correlated negatively with changes in the proportion of HDL2a (r = -0.597, p = 0.0002) and positively with changes in the proportion of HDL3b (r = 0.457, p = 0.0075). On the other hand, changes in plasma PLTP activity correlated positively with changes in the proportion of HDL2b (r = 0.482, p = 0.0045) and negatively with changes in the proportion of HDL3a (r = -0.418, p = 0.0154). Taken together, data of the present study revealed that plasma PLTP and CETP can exert opposite effects on the size distribution of plasma HDL. PLTP can promote the formation of HDL2b particles at the expense of HDL3a, while CETP can promote the formation of HDL3b particles at the expense of HDL2a.

Effects of alcohol on plasma lipoprotein metabolism

Alcohol consumption affects a number of steps in plasma lipoprotein metabolism: it serves as a substrate for lipoprotein triglyceride synthesis, alters synthesis of apolipoproteins, and affects the activity of the key enzymes of lipoprotein metabolism, namely lipoprotein lipase and hepatic lipase, and cholesterol ester transfer protein. In addition, alcohol consumption may increase tissue sensitivity to insulin. The specific effects of alcohol consumption vary and depend on the amount ingested, type of drinking (as opposed to moderate regular alcohol consumption, binge drinking results in an unfavourable serum lipoprotein profile), body composition of the drinkers and a number of gene/environment interactions. Modification of lipoproteins by acetaldehyde, the product of ethanol metabolism or by antioxidants present in some alcoholic beverages also influences the lipoprotein alterations due to alcohol consumption. Moderate alcohol consumption increases serum high density lipoprotein cholesterol and may decrease the concentration of lipoprotein(a).

HDL heterogeneity and atherosclerosis

High-density lipoprotein (HDL), the most abundant human plasma lipoprotein, plays a major role in reverse cholesterol transport, which recycles cholesterol from peripheral cells to the liver. HDL constitutes a heterogeneous group of particles differing in density, size, electrophoretic mobility, and apolipoprotein content. HDL can therefore be fractionated into discrete subclasses by different techniques according to their physicochemical properties. The clinical significance of HDL differs with the subclasses, especially with respect to coronary heart disease, alcohol intake, longevity, dyslipoproteinemia, dietary fat content, and hypolipidemic drugs. Because of their structural and functional diversity, HDL subclasses generate considerable hope that they may help to improve the identification of individuals at an increased risk of developing coronary heart disease.

Alcohol intake modulates the effect of a polymorphism of the cholesteryl ester transfer protein gene on plasma high density lipoprotein and the risk of myocardial infarction

A polymorphism of the CETP gene (CETP/TaqIB) with two alleles B1 (60%) and B2 (40%) has been investigated in relation to lipid variables and the risk of myocardial infarction in a large case-control study (ECTIM) of men aged 25-64. No association was observed between the polymorphism and LDL or VLDL related lipid variables. Conversely, B2 carriers had reduced levels of plasma CETP (P < 0.0001) and increased levels of HDL cholesterol (P < 0.0001) and of other HDL related lipid variables. The effects of the polymorphism on plasma CETP and HDL cholesterol were independent, suggesting the presence of at least two functional variants linked to B2. A search for these variants on the coding sequence of the CETP gene failed to identify them. The effect of B2 on plasma HDL cholesterol was absent in subjects drinking < 25 grams/d of alcohol but increased commensurably, with higher values of alcohol consumption (interaction: P < 0.0001). A similar interaction was not observed for plasma CETP. The odds-ratio for myocardial infarction of B2 homozygotes decreased from 1.0 in nondrinkers to 0.34 in those drinking 75 grams/d or more. These results provide the first demonstration of a gene-environment interaction affecting HDL cholesterol levels and coronary heart disease risk.

Beyond alcohol: beverage consumption and cardiovascular mortality

This paper reviews epidemiological investigations which have identified an inverse relationship between alcohol consumption and death from coronary heart disease: evidence from studies of mixed populations as well as of single-sex populations have, on the whole, demonstrated that this relationship is independent of sex or age. This 'cardioprotective effect' of alcohol can be explained, at least in part, by ethanol-related increases in high density lipoprotein cholesterol and reduced platelet coagulability. With certain beverages, especially red wine, phenolic compounds may provide additional protection by altering eicosanoid metabolism in favour of increased prostacyclin and decreased thromboxane synthesis, as well as antioxidant functions which prevent the peroxidation of low-density lipoprotein. Trans-resveratrol, a tri-hydroxy stilbene present in the skins of specific grape cultivars, is a constituent of certain red wines which may play a crucial role in modulating lipoprotein metabolism, eicosanoid synthesis, oxidation and coagulation. Preliminary studies using the human hepatoma cell line HepG2 are described, demonstrating that this compound has no effect upon cell viability or overall protein synthesis in these cells, and at high concentrations DNA synthesis as measured by radioactive thymidine incorporation is enhanced. Reduced intracellular concentration and secretion of apolipoprotein B have been shown to occur in response to resveratrol although a clear dose-dependency has not yet been demonstrated. The mechanisms underlying these changes as well as the effects upon the synthesis and secretion of other apolipoproteins are under active investigation in our laboratory.

Effects of alcohol on lipoprotein lipase, hepatic lipase, cholesteryl ester transfer protein, and lecithin:cholesterol acyltransferase in high-density lipoprotein cholesterol elevation

The mechanism whereby alcohol increases high-density lipoprotein cholesterol (HDL-C) levels is unclear. Lipoprotein lipase (LPL), hepatic lipase (HL), cholesteryl ester transfer protein (CETP) and lecithin:cholesterol acyltransferase (LCAT) act on lipoprotein metabolism. The purpose of the present study is to determine which one or what combination of these factors is responsible for the rise in HDL-C levels following alcohol ingestion. After 3 weeks of abstinence, 12 men consumed 0.5 g/kg bw of alcohol per day for 4 weeks; 13 abstaining men served as controls. Mean plasma total cholesterol (TC) levels were unchanged in either group throughout the study. Among the alcohol consumers, plasma triglycerides (TG), HDL-C, apolipoprotein (apo) A-I and A-II levels increased significantly after 3 weeks of alcohol loading but were unchanged in the control group. High-density lipoprotein3 cholesterol (HDL3-C) levels increased significantly in the alcohol consumers after 4 weeks of alcohol loading whereas high-density lipoprotein2 cholesterol (HDL2-C) levels were unaffected. In the controls, neither HDL2-C nor HDL3-C changed significantly. Post-heparin plasma (PHP) LPL activity and mass increased significantly (P < 0.01) after the alcohol ingestion (controls remained unchanged) without changing LPL specific activity. HL, CETP and LCAT activities were unaffected in both groups. We conclude that of the factors considered, LPL contributed the most to the alcohol-induced rise in HDL-C.