Beneficial effects of alcohol withdrawal on LDL particle size distribution and oxidative susceptibility in subjects with alcohol-induced hypertriglyceridemia

Effects of N-acetylcysteine on alcohol abstinence and alcohol-induced adverse effects in rats

Alcoholism is rampant in modern society and some antioxidant compound could perhaps be useful to reduce the damage done by alcohol consumption and abstinence. The present study was undertaken to investigate the association of N-acetylcysteine (NAC) intake, alcoholism, and alcohol abstinence on lipid profile, in vivo low-density lipoprotein (LDL) oxidation, oxidative stress, and antioxidant status in serum and liver of rats. Initially, male Wistar 30 rats were divided into two groups: (C, N=6) given standard chow and water; (E, N=24) receiving standard chow and aqueous ethanol solution in semi-voluntary research. After 30 days of ethanol exposure, (E) group was divided into four subgroups (N=6/group): (E-E) continued drinking 30% ethanol solution; (E-NAC) drinking ethanol solution containing 2 g/L NAC; (AB) changed ethanol solution to water; (AB-NAC) changed ethanol to aqueous solution 2 g/L NAC. After 15 days of the E-group division, E-E rats had higher serum alanine transaminase, lower body weight, and surface area, despite higher energy intake than C. E-E rats had also lower feed efficiency, dyslipidemia with enhanced triacylglycerol, very low-density lipoprotein (VLDL), lipid hydroperoxide (LH) and in vivo oxidized-LDL (ox-LDL). AB, E-NAC, and AB-NAC rats ameliorated serum oxidative stress markers and normalized serum lipids. E-E rats had higher hepatic LH and lower reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio than C, indicating hepatic oxidative stress. AB and E-NAC rats normalized hepatic LH, GSSG, and the GSH/GSSG ratio, compared to E-E. AB-NAC rats had the lowest serum ox-LDL, hepatic LH levels, and the highest GSH reductase activity in hepatic tissue. In conclusion, the present study brought new insights into alcohol consumption, because ethanol exposure enhanced serum in vivo ox-LDL, as well as serum and hepatic oxidative stress. N-acetylcysteine offers promising therapeutic value to inhibit ethanol-induced adverse effects. Ethanol withdrawal had beneficial effects on serum lipids, but was more effective when coupled with NAC supplementation. Ethanol abstinence and NAC intake interact synergistically, improving serum lipids and hepatic antioxidant defenses.

Grape products and cardiovascular disease risk factors

Many in vivo trials have evaluated the effects of grape products on different CVD risk factors. Most published studies have dealt with some specific aspects of mechanisms of grape flavonoid action or have focused only on one product, such as wine. The aim of the present paper is to review trials dealing with grape products and CVD published during the last 13 years (seventy-five trials). Polyphenols, alcohol and dietary fibre are the main constituents of the tested products. In animal and human studies, grape products have been shown to produce hypotensive, hypolipidaemic and anti-atherosclerotic effects, and also to improve antioxidant status as measured in terms of plasma antioxidant capacity, oxidation biomarkers, antioxidant compounds or antioxidant enzymes. Differences in the design of the studies and in the composition of the tested products (not always provided) could explain the different results of these studies.

Alcohol consumption and lipoprotein subclasses in older adults

CONTEXT

Limited evidence suggests that alcohol intake may be associated with lipoprotein subclass distribution, which could mediate its relationship with coronary heart disease.

OBJECTIVES

The objective was to determine the relationship of alcohol intake with lipoprotein particle subclasses.

DESIGN, SETTING, AND PARTICIPANTS

The study included a cross-sectional analysis of 1850 participants of the Cardiovascular Health Study aged 65 yr and older and free of clinical cardiovascular disease.

MAIN OUTCOME MEASURE

Lipoprotein subclass distribution was measured with nuclear magnetic resonance spectroscopy, according to self-reported alcohol intake.

RESULTS

Alcohol intake was associated with total low-density lipoprotein (LDL) particles in a U-shaped manner. Consumers of one or more drinks per week had the highest number of large LDL particles, whereas consumers of 7-13 drinks per week had the lowest number of small LDL particles. Alcohol intake was strongly positively associated with large- and medium-sized high-density lipoprotein (HDL) particles but had an inverse relationship with concentrations of small HDL particles and small- and medium-sized very-low-density lipoprotein particles. Average particle sizes of all three lipoproteins were positively associated with alcohol intake. Associations were generally stronger among women than men but in similar directions. Beverage type did not consistently modify these findings.

CONCLUSIONS

Alcohol intake is associated with less total LDL particles, lower levels of small LDL, HDL, and very-low-density lipoprotein particles, and higher levels of large LDL and medium- and large-sized HDL particles in older adults free of prevalent clinical cardiovascular disease.

Steatotic liver allografts up-regulate UCP-2 expression and suffer necrosis in rats

BACKGROUND

Fatty split-liver and living-related liver transplantation is associated with massive hepatocellular necrosis during acute rejection. Uncoupling protein (UCP)-2 is a potential regulator of energy expenditure and ATP production. We investigated the role of UCP-2 and the effects of a metalloprotease inhibitor, Y-39083, on hepatocellular injury in fatty liver allografts in rats.

MATERIALS AND METHODS

Rats were treated for 6 weeks with high-ethanol or isocalic dextrose-containing liquid diets that caused characteristic pericentral lipid accumulation. Alcoholic or nonalcoholic fatty livers from ACI (RT1a) rats were transplanted into LEW (RT1l) rats orthotopically. Hepatic necrosis was determined histologically following liver transplantation. UCP-2 mRNA levels in the hepatic allograft and in primary cultured hepatocytes from fatty liver stimulated by tumor necrosis factor (TNF)-alpha were determined. Y-39083 was administered to recipient rats continuously at 5 mg/kg/day using an osmotic infusion mini-pump.

RESULTS

The acute rejection index on day 5 posttransplant in alcoholic and nonalcoholic fatty donor livers was higher than in lean grafts. Massive hepatocyte necrosis was more prominent in alcoholic than nonalcoholic fatty liver allografts and was not seen in lean allografts. UCP-2 transcripts in both alcoholic and nonalcoholic fatty liver allografts were higher than in lean allografts. Serum TNF-alpha concentrations in recipient rats with either fatty liver allograft were greater than in animals with lean allografts. In vitro UCP-2 mRNA levels in primary cultured hepatocytes from both alcoholic and nonalcoholic fatty livers increased more after stimulation with TNF-alpha than those from lean livers. In vitro TNF-alpha production by Kupffer cells isolated from alcohol-induced fatty liver allografts on day 3 posttransplant was greater than those from lean allografts. Y-39083 significantly reduced serum concentrations of TNF-alpha and prevented massive hepatocellular necrosis in rats with both alcoholic and nonalcoholic fatty liver allografts.

CONCLUSION

Liver grafts with steatosis up-regulated UCP-2. TNF-alpha further enhanced UCP-2 transcripts, inducing massive hepatocellular necrosis during acute rejection. Posttransplantation necrosis may be prevented by metalloprotease inhibitors.

Acute alcohol consumption improves insulin action without affecting insulin secretion in type 2 diabetic subjects

OBJECTIVE

Long-term exposure to alcohol is associated with an improvement in insulin sensitivity. At this time, however, there is no definitive proof that alcohol per se has an effect on the insulin sensitivity index (S(i)) in type 2 diabetes patients. The aim of the present study was to assess the role of acute moderate alcohol intake on insulin sensitivity and insulin secretion in comparable subjects with and without type 2 diabetes.

RESEARCH DESIGN AND METHODS

Frequently sampled intravenous glucose tolerance tests (FSIGTs) were performed twice on eight healthy and eight type 2 diabetic volunteers. Forty grams of alcohol (vodka 40% wt/vol) or tap water were sipped from time -60 min to the end of the FSIGT.

RESULTS

Lactate area under the curve (AUC) was higher in both groups during the alcohol study than in the control study. Free fatty acid (FFA) AUC was higher in type 2 diabetic subjects than in control subjects; alcohol slightly reduced FFA by 17% in control subjects (34 +/- 4 mmol. min(-1). l(-1); P = 0.1) but significantly decreased FFA by 23% in type 2 diabetic subjects (54 +/- 10; P = 0.007). Beta-cell response was markedly reduced in type 2 diabetic subjects regardless of the type of study. Alcohol significantly increased S(i) in both groups.

CONCLUSIONS

Acute alcohol consumption improves insulin action without affecting beta-cell secretion. This effect may be partly due to the inhibitory effect of alcohol on lipolysis. Alcohol intake increases insulin sensitivity and may partly explain both the J-shaped relationship between the prevalence of diabetes and the amount of alcohol consumption and the decreased mortality for myocardial infarction.

Oxidized low-density lipoprotein autoantibodies in patients with primary gout: effect of urate-lowering therapy

BACKGROUND

Uric acid is a strong scavenger of reactive oxygen species, which are known to contribute to the development of atherosclerosis, while the incidence of atherosclerotic diseases is rather high in patients with gout. Among the established risk factors for atherosclerosis, oxidized LDL is believed to play a major role in its development and progression. Allopurinol and its active metabolite, oxypurinol, have been suggested to possess an antioxidant ability to scavenge the hydroxyl radical. Therefore, allopurinol may be beneficial in the prevention of LDL oxidation, as well as in the treatment of hyperuricemia. The objective of this work was to determine the degree of LDL oxidation in gout and the effect of allopurinol on LDL oxidation.

METHODS

Age-matched male patients with primary intercritical gout and healthy male adults were included in the study. The serum concentrations of oxidized LDL autoantibodies and total antioxidant status were measured using an enzyme immunoassay.

RESULTS

Serum concentrations of oxidized LDL autoantibodies were significantly higher in patients with gout than the control subjects (p < 0.05) and were significantly decreased after allopurinol treatment (p < 0.05), but not by benzbromarone treatment, in spite of the similar concentrations of uric acid and total antioxidant status in serum following their separate administration.

CONCLUSIONS

Although the exact mechanism remains unclear, increased serum concentrations of oxidized LDL may play a role in the high incidence of coronary artery disease in gout. In addition, allopurinol may be more preferable to benzbromarone for treatment of gout in light of its inhibitory action toward LDL oxidation.

Oxidized LDL autoantibodies are related to apolipoprotein E phenotype, independently of postprandial change in plasma triglycerides and LDL size, among patients with angiographically verified coronary artery disease and healthy controls

OBJECTIVE

Oxidized low-density lipoprotein (LDL) autoantibodies (oxLDLab), apolipoprotein E (apoE) phenotype, postprandial triglyceride changes and LDL size are suggested to be risk factors for coronary artery disease (CAD). Our aim was to study the interaction between these new risk factors among patients with CAD and healthy controls.

METHODS

oxLDLab from 31 men with angiographically verified CAD and 31 healthy men were analyzed by enzyme-linked immunosorbent assay. Isoelectric focusing and immunoblotting were used for apoE phenotyping. Triglyceride level was measured after 12 h of fasting and 3, 5 and 7 h after a high-fat meal. Nondenaturing gradient gel electrophoresis was used to separate LDL particles according to size.

RESULTS

oxLD- Lab levels increased according to apoE phenotype in the following order: E2 < E3 < E4 (p = 0.004, ANOVA). The postprandial response of triglycerides, the size of LDL particles and the concentration of LDL and high-density lipoprotein (HDL) cholesterol did not differ between apoE phenotypes, and the use of these variables as covariates did not change the statistically significant difference in oxLDLab levels between apoE phenotypes (p = 0.01, ANCOVA). oxLDLab levels did not differ between the patient and control groups.

CONCLUSION

We found an association between apoE allele epsilon2 and decreased levels of oxLDLab, which was independent of the postprandial response of triglycerides, the size of LDL particles and plasma LDL and HDL cholesterol levels. The mechanism by which apoE affects oxidation of LDL remains unknown.

Effect of atorvastatin on lipid parameters, LDL subtype distribution, hemorrheological parameters and adhesion molecule concentrations in patients with hypertriglyceridemia

BACKGROUND AND AIM

Hypertriglyceridemia is a risk factor for atherosclerosis that is typically associated with high concentrations of adhesion molecules, impaired hemorrheology and an unfavourable low-density lipoprotein (LDL) subtype distribution. We hypothesised that some of these risk markers might be beneficially influenced by lipid-lowering therapy with atorvastatin in hypertriglyceridemic patients.

METHODS AND RESULTS

Nineteen patents with primary hypertriglyceridemia were given 10 mg of atorvastatin per day for four weeks. Their cholesterol, triglyceride, LDL and high-density lipoprotein cholesterol (HDL-C) levels, LDL subtype profile, hemorrheological parameters and E-selectin, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 concentrations were measured before and at the end of atorvastatin therapy. The levels of total and LDL cholesterol respectively decreased by 25% and 24% (both p < 0.001). Furthermore, cholesterol was reduced by 8-29% in all seven LDL subfractions (density range: 1.020-1.066 g/mL) (p < 0.05). The reduction in triglyceride concentrations was of marginal significance (9%, p = 0.1), but its degree positively correlated with the reduction of small-dense LDL (r = 0.5, p < 0.025). Plasma viscosity and blood viscosity at low shear rates were respectively reduced by 2% and 16% (both p < 0.05). The effect of the treatment on the concentrations of HDL-C, fibrinogen and adhesion molecules was not significant.

CONCLUSIONS

Atorvastatin (10 mg/day) not only reduced the plasma concentrations of atherogenic lipoproteins but also improved the LDL-subtype profile and reduced plasma and blood viscosity in patients with hypertriglyceridemia; however, it failed to significantly lower triglyceride concentrations.

Red wine raises plasma HDL and preserves long-chain polyunsaturated fatty acids in rat kidney and erythrocytes

The effects of red wine and ethanol on plasma lipoproteins and the fatty acid composition of kidney lipids and erythrocytes phospholipids were studied. Lipid peroxidation is one of the main deleterious effects of oxidant attack on biomolecules, due to the disruption of the structural integrity of membranes. The vulnerability of the kidney to oxidative damage has been partly attributed to its high content of long-chain polyunsaturated fatty acids. Antioxidants, such as flavonoids, would be a means of reducing the risk of oxidative damage to membranes. Nutritional sources rich in antioxidants, including those provided by wine, are expected to attenuate the effects of oxidative challenges. Adult rats were fed red wine rich in flavonols, ethanol (125 ml/l), or alcohol-free red wine. The control group drank water. After 10 weeks, blood samples served to measure plasma lipoproteins and antioxidant capacity. Kidney lipids and erythrocyte phospholipids were extracted. The samples were assayed by GLC. Energy intake did not differ between all the groups, but the weight gain of the ethanol group was less than the other three groups. Blood HDL and triacylglycerols were increased by both ethanol and red wine. Ethanol decreased arachidonic and docosahexaenoic acids in both kidney lipids and erythrocyte phospholipids, as compared with either water, red wine or alcohol-free red wine groups. These results indicate that non-alcoholic components of red wine could contribute to avoiding the unfavourable effects of ethanol on plasma lipoproteins, kidney lipids and membrane erythrocyte phospholipids.

Alcohol drinking determines the effect of the APOE locus on LDL-cholesterol concentrations in men: the Framingham Offspring Study

BACKGROUND

The effect of alcohol drinking on LDL-cholesterol concentrations is unclear. The reported variability may be due to interactions between genetic factors and alcohol intake.

OBJECTIVE

The purpose of the study was to examine whether variation at the apolipoprotein E gene (APOE) locus modulates the association between alcohol drinking and LDL cholesterol.

DESIGN

We used a cross-sectional design in a healthy population-based sample of 1014 men and 1133 women from the Framingham Offspring Study.

RESULTS

In male nondrinkers (n = 197), LDL cholesterol was not significantly different across APOE allele groups [APOE*E2 (E2), APOE*E3 (E3), and APOE*E4 (E4)]. However, in male drinkers (n = 817), differences were observed (P: < 0.001); those with the E2 allele had the lowest concentrations. LDL cholesterol in men with the E2 allele was significantly lower in drinkers than in nondrinkers but was significantly higher in drinkers than in nondrinkers in men with the E4 allele. This APOE-alcohol interaction remained significant (P < 0.001) after age, body mass index, smoking status, and fat and energy intakes were controlled for. In women, the expected effect of APOE alleles on LDL cholesterol occurred in both drinkers (n = 791; P < 0.001) and nondrinkers (n = 342; P < 0.001). Multiple linear regression models showed a negative association (P < 0.05) between alcohol and LDL cholesterol in men with the E2 allele but a positive association in men with the E4 allele. No significant associations were observed in men or women with the E3 allele.

CONCLUSION

In men, the effects of alcohol intake on LDL cholesterol are modulated in part by variability at the APOE locus.

The health benefits of wine

Epidemiologic studies from numerous disparate populations reveal that individuals with the habit of daily moderate wine consumption enjoy significant reductions in all-cause and particularly cardiovascular mortality when compared with individuals who abstain or who drink alcohol to excess. Researchers are working to explain this observation in molecular and nutritional terms. Moderate ethanol intake from any type of beverage improves lipoprotein metabolism and lowers cardiovascular mortality risk. The question now is whether wine, particularly red wine with its abundant content of phenolic acids and polyphenols, confers additional health benefits. Discovering the nutritional properties of wine is a challenging task, which requires that the biological actions and bioavailability of the >200 individual phenolic compounds be documented and interpreted within the societal factors that stratify wine consumption and the myriad effects of alcohol alone. Further challenge arises because the health benefits of wine address the prevention of slowly developing diseases for which validated biomarkers are rare. Thus, although the benefits of the polyphenols from fruits and vegetables are increasingly accepted, consensus on wine is developing more slowly. Scientific research has demonstrated that the molecules present in grapes and in wine alter cellular metabolism and signaling, which is consistent mechanistically with reducing arterial disease. Future research must address specific mechanisms both of alcohol and of polyphenolic action and develop biomarkers of their role in disease prevention in individuals.