Long-term ethanol consumption impairs reverse cholesterol transport function of high-density lipoproteins by depleting high-density lipoprotein sphingomyelin both in rats and in humans

Exploring the complex interplay between alcohol consumption and cardiovascular health: Mechanisms, evidence, and future directions

This review article explores the intricate relationship between alcohol consumption and cardiovascular health, underscoring on both clinical outcomes and underlying pathophysiological mechanisms. It examines the complex dose-response relationships for various cardiovascular disease (CVD) subtypes, including coronary heart disease, stroke, and atrial fibrillation, while categorizing pathophysiological mechanisms into three conceptual areas: primary initiating factors, secondary transmission pathways, and end-organ effects. Although mild-to-moderate alcohol consumption may confer some benefits for cardiovascular health and certain CVD subtypes, growing evidence highlights the importance of lifestyle modifications to reduce alcohol intake, particularly among heavy drinkers. This review provides a comprehensive overview of current knowledge, emphasizes the need for future research with robust methodologies, and advocates for incorporating updated scientific evidence into personalized approaches within international cardiovascular and national guidelines.

Additive Effects of Drinking Habits and a Susceptible Genetic Polymorphism on Cholesterol Efflux Capacity

AIMS

High levels of high-density lipoprotein cholesterol (HDL-C) are not necessarily effective in preventing atherosclerotic cardiovascular disease, and cholesterol efflux capacity (CEC) has attracted attention regarding HDL functionality. We aimed to elucidate whether drinking habits are associated with CEC levels, while also paying careful attention to confounding factors including serum HDL-C levels, other life style factors, and rs671 (＊2), a genetic polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene determining alcohol consumption habit.

METHODS

A cross-sectional study was performed in 505 Japanese male subjects who were recruited from a health screening program. Associations of HDL-C and CEC levels with drinking habits and ALDH2 genotypes were examined.

RESULTS

The genotype frequencies of ALDH2 ＊1/＊1 (homozygous wild-type genotype), ＊1/＊2 and ＊2/＊2 (homozygous mutant genotype) were 55%, 37% and 8%, respectively. Both HDL-C and CEC levels were higher in ALDH2 ＊1/＊1 genotype carriers than in ＊2 allele carriers. Although HDL-C levels were higher in subjects who had a drinking habit than in non-drinkers, CEC levels tended to be lower in subjects with ≥ 46 g/day of alcohol consumption than in non-drinkers. Furthermore, CEC levels tended to be lower in ALDH2 ＊1/＊1 genotype carriers with a drinking habit of ≥ 46 g/day than non-drinkers, while for ＊2 allele carriers, CEC levels tended to be lower with a drinking habit of 23-45.9 g/day compared to no drinking habit.

CONCLUSIONS

Our results suggest that heavy drinking habits may tend to decrease CEC levels, and in the ALDH2 ＊2 allele carriers, even moderate drinking habits may tend to decrease CEC levels.

Long-Term Alcohol Consumption Caused a Significant Decrease in Serum High-Density Lipoprotein (HDL)-Cholesterol and Apolipoprotein A-I with the Atherogenic Changes of HDL in Middle-Aged Korean Women

Light-to-moderate alcohol drinking is associated with a low incidence of cardiovascular disease (CVD) via an elevation of high-density lipoproteins-cholesterol (HDL-C), particularly with the short-term supplementation of alcohol. However, there is no information on the change in the HDL qualities and functionalities between non-drinkers and mild drinkers in the long-term consumption of alcohol. This study analyzed the lipid and lipoprotein profiles of middle-aged Korean female non-drinkers, mild-drinkers, and binge-drinkers, who consumed alcohol for at least 10 years. Unexpectedly, the serum levels of HDL-C and apolipoprotein A-I (apoA-I) were decreased significantly depending on the alcohol amount; the binge-drinker group showed 18% and 13% lower HDL-C (p = 0.011) and apoA-I levels (p = 0.024), respectively, than the non-drinker group. Triglyceride (TG) and oxidized species, malondialdehyde (MDA), and low-density lipoproteins (LDL) levels were significantly elevated in the drinker groups. Interestingly, the binge-drinker group showed 1.4-fold higher (p = 0.020) cholesterol contents in HDL2 and 1.7-fold higher (p < 0.001) TG contents in HDL3 than those of the non-drinker group. The mild-drinker group also showed higher TG contents in HDL3 (p = 0.032) than the non-drinker group, while cholesterol contents were similar in the HDL3 of all groups. Transmission electron microscopy (TEM) showed that the non-drinker group showed a more distinct and clear particle shape of the LDL and HDL image with a larger particle size than the drinker group. Electrophoresis of LDL showed that the drinker group had faster electromobility with a higher smear band intensity and aggregation in the loading position than the non-drinker group. The HDL level of binge drinkers showed the lowest paraoxonase activity, the highest glycated extent, and the most smear band intensity of HDL and apoA-I, indicating that HDL quality and functionality were impaired by alcohol consumption. In conclusion, long-term alcohol consumption in middle-aged women, even in small amounts, caused a significant decrease in the serum HDL-C and apoA-I with atherogenic changes in LDL and HDL, such as an increase in TG and MDA content with a loss of paraoxonase activity.

Alcohol and Metabolic-associated Fatty Liver Disease

The diagnosis of metabolic-associated fatty liver disease is based on the detection of liver steatosis together with the presence of metabolic dysfunction. According to this new definition, the diagnosis of metabolic-associated fatty liver disease is independent of the amount of alcohol consumed. Actually, alcohol and its metabolites have various effects on metabolic-associated abnormalities during the process of alcohol metabolism. Studies have shown improved metabolic function in light to moderate alcohol drinkers. There are several studies focusing on the role of light to moderate alcohol intake on metabolic dysfunction. However, the results from studies are diverse, and the conclusions are often controversial. This review systematically discusses the effects of alcohol consumption, focusing on light to moderate alcohol consumption, obesity, lipid and glucose metabolism, and blood pressure.

Environmental Factors Modifying HDL Functionality

BACKGROUND

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

INTRODUCTION

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

METHOD

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

RESULT

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

CONCLUSION

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

High Density Lipoprotein Cholesterol Efflux Capacity and Atherosclerosis in Cardiovascular Disease: Pathophysiological Aspects and Pharmacological Perspectives

Over the years, the relationship between high-density lipoprotein (HDL) and atherosclerosis, initially highlighted by the Framingham study, has been revealed to be extremely complex, due to the multiple HDL functions involved in atheroprotection. Among them, HDL cholesterol efflux capacity (CEC), the ability of HDL to promote cell cholesterol efflux from cells, has emerged as a better predictor of cardiovascular (CV) risk compared to merely plasma HDL-cholesterol (HDL-C) levels. HDL CEC is impaired in many genetic and pathological conditions associated to high CV risk such as dyslipidemia, chronic kidney disease, diabetes, inflammatory and autoimmune diseases, endocrine disorders, etc. The present review describes the current knowledge on HDL CEC modifications in these conditions, focusing on the most recent human studies and on genetic and pathophysiologic aspects. In addition, the most relevant strategies possibly modulating HDL CEC, including lifestyle modifications, as well as nutraceutical and pharmacological interventions, will be discussed. The objective of this review is to help understanding whether, from the current evidence, HDL CEC may be considered as a valid biomarker of CV risk and a potential pharmacological target for novel therapeutic approaches.

Enhanced Alcohol Preference and Anxiolytic Alcohol Effects in Niemann-Pick Disease Model in Mice

Major depression and alcohol use disorder are severe psychiatric diseases affecting the world's population with high comorbidity level. However, the pathogenesis of this comorbidity remains unclear, and no selective treatment for this condition is available. A pathogenic pathway and a possible therapeutic target for the treatment of depression-alcoholism comorbidity based on the hyperfunction of acid sphingomyelinase (Asm) were recently suggested. Here we analyzed the effects of alcohol on the depression/anxiety state of homozygous Asm-knockout mice (Asm − /−), which can be considered as a model of an early stage of Niemann-Pick disease, as well as their drinking pattern under normal and stress conditions. It was observed that forced treatment with alcohol (2 g/kg, i.p.) reduces the anxiety level of Asm−/− mice as measured in the elevated plus maze (EPM) test, but enhances the depression level in the forced swim test (FST). The analysis of drinking pattern of these animals in a free-choice alcohol drinking paradigm revealed higher alcohol intake and preference in Asm−/− mice compared to wild type (wt) littermates. However, this difference was overwritten by the stress exposure. Stronger sedating effects of alcohol were observed in Asm−/− mice compared to wt animals in the loss of righting reflex test after single and repeated alcohol injections (3 g/kg, i.p.). Altogether, the present findings might indicate an Asm involvement in the mechanisms of comorbidity between alcoholism and anxiety/depression.

Low-ω3 Fatty Acid and Soy Protein Attenuate Alcohol-Induced Fatty Liver and Injury by Regulating the Opposing Lipid Oxidation and Lipogenic Signaling Pathways

Chronic ethanol-induced downregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) and upregulation of peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC1β) affect hepatic lipid oxidation and lipogenesis, respectively, leading to fatty liver injury. Low-ω3 fatty acid (Low-ω3FA) that primarily regulates PGC1α and soy protein (SP) that seems to have its major regulatory effect on PGC1β were evaluated for their protective effects against ethanol-induced hepatosteatosis in rats fed with Lieber-deCarli control or ethanol liquid diets with high or low ω3FA fish oil and soy protein. Low-ω3FA and SP opposed the actions of chronic ethanol by reducing serum and liver lipids with concomitant decreased fatty liver. They also prevented the downregulation of hepatic Sirtuin 1 (SIRT1) and PGC1α and their target fatty acid oxidation pathway genes and attenuated the upregulation of hepatic PGC1β and sterol regulatory element-binding protein 1c (SREBP1c) and their target lipogenic pathway genes via the phosphorylation of 5' adenosine monophosphate-activated protein kinase (AMPK). Thus, these two novel modulators attenuate ethanol-induced hepatosteatosis and consequent liver injury potentially by regulating the two opposing lipid oxidation and lipogenic pathways.

HDL-sphingomyelin reduction after weight loss by an energy-restricted diet is associated with the improvement of lipid profile, blood pressure, and decrease of insulin resistance in overweight/obese patients

BACKGROUND

Sphingomyelin (SM) diminishes the fluidity of the surface monolayer of high-density lipoproteins (HDL), affecting their intravascular metabolism and antiatherogenic properties. Since overweight is associated with an altered HDL structure, weight loss may result in changes in HDL subclasses, particularly in their SM content. Therefore, we determined the plasma SM concentrations associated to both total HDL and HDL subclasses after weight loss in obese patients.

METHODS

Fifty overweight patients, 40 women and 10 men, aged 38.6±6.4 y, were given an energy-restricted diet according to their sex, age, and height. No physical activity was prescribed. Plasma SM concentrations of HDL subclasses were determined by a gel surface method developed for this study. Cholesterol of HDL subclasses was also determined by enzymatic methods performed on a gel surface.

RESULTS

Mean weight lost was 3.5±0.4 kg after 6 weeks of dietary intervention. As expected, insulin resistance and blood pressure decreased whereas lipid profile improved, except for HDL-cholesterol. SM in plasma and in all HDL subclasses significantly decreased after intervention. The magnitude of HDL-SM reduction was statistically associated with the amelioration of the components of the metabolic syndrome; the reduction of BMI explained the decrement of HDL-SM in a multivariate analysis.

CONCLUSION

HDL-SM decreased after weight loss by an energy-restricted diet. Further, the association of this decrement with the improvement of blood pressure, lipid profile and the decrease of insulin resistance, was statistically significant; all HDL subclasses were similarly affected. Whether a reduction in HDL-SM contributes to the cardiovascular benefits of weight loss remains to be elucidated.

HDL and lifestyle interventions

The main lifestyle interventions to modify serum HDL cholesterol include physical exercise, weight loss with either caloric restriction or specific dietary approaches, and smoking cessation. Moderate alcohol consumption can be permitted in some cases. However, as these interventions exert multiple effects, it is often difficult to discern which is responsible for improvement in HDL outcomes. It is particularly noteworthy that recent data questions the use of HDL cholesterol as a risk factor and therapeutic target since randomised interventions and Mendelian randomisation studies failed to provide evidence for such an approach. Therefore, these current data should be considered when reading and interpreting this review. Further studies are needed to document the effect of lifestyle changes on HDL structure-function and health.

Adverse signaling of scavenger receptor class B1 and PGC1s in alcoholic hepatosteatosis and steatohepatitis and protection by betaine in rat

Because scavenger receptor class B type 1 is the cholesterol uptake liver receptor, whereas peroxisome proliferator-activated receptor γ coactivator-1β (PGC-1β) and PGC-1α are critical for lipid synthesis and degradation, we investigated the roles of these signaling molecules in the actions of ethanol-polyunsaturated fatty acids and betaine on hepatosteatosis and steatohepatitis. Ethanol-polyunsaturated fatty acid treatment caused the following: i) hepatosteatosis, as evidenced by increased liver cholesterol and triglycerides, lipid score, and decreased serum adiponectin; ii) marked inhibition of scavenger receptor class B type 1 glycosylation, its plasma membrane localization, and its hepatic cholesterol uptake function; and iii) moderate steatohepatitis, as evidenced by histopathological characteristics, increased liver tumor necrosis factor α and IL-6, decreased glutathione, and elevated serum alanine aminotransferase. These actions of ethanol involved up-regulated PGC-1β, sterol regulatory element-binding proteins 1c and 2, acetyl-CoA carboxylase, and HMG-CoA reductase mRNAs/proteins and inactive non-phosphorylated AMP kinase; and down-regulated silence regulator gene 1 and PGC-1α mRNA/proteins and hepatic fatty acid oxidation. Betaine markedly blunted all these actions of ethanol on hepatosteatosis and steatohepatitis. Therefore, we conclude that ethanol-mediated impaired post-translational modification, trafficking, and function of scavenger receptor class B type 1 may account for alcoholic hyperlipidemia. Up-regulation of PGC-1β and lipid synthetic genes and down-regulation of silence regulator gene 1, PGC-1α, adiponectin, and lipid degradation genes account for alcoholic hepatosteatosis. Induction of proinflammatory cytokines and depletion of endogenous antioxidant, glutathione, account for alcoholic steatohepatitis. We suggest betaine as a potential therapeutic agent because it effectively protects against adverse actions of ethanol.

Novel modulators of hepatosteatosis, inflammation and fibrogenesis

Alcoholic steatosis, instead of being innocuous, plays a critical role in liver inflammation and fibrogenesis. The severity of fatty liver is governed by the concerted balance between lipid transport, synthesis, and degradation. Whereas scavenger receptor class B, type I (SR-B1) is critical for reverse cholesterol uptake by the liver, peroxisome proliferator-activated receptor-gamma (PPARγ) coactivator-1α and -β (PGC1α and PGC1β) are critical for lipid degradation and synthesis, respectively. Because betaine is a lipotropic agent, we have evaluated its effects on alcoholic steatosis. Betaine effectively prevented chronic alcohol-mediated (i) impaired SR-B1 glycosylation, plasma membrane localization, and consequent impaired cholesterol transport; and (ii) up regulation of PGC-1β, sterol regulatory element-binding protein 1c and downstream lipogenic genes with concomitant increased liver cholesterol, triglycerides and hepatic lipid score. Similarly, because of its anti-inflammatory and anti-fibrotic effects in other organs, we evaluated the protective effects of thymosin β4 (Tβ4) against carbon tetrachloride (CCl4)-induced hepatotoxicity in rat. Tβ4 prevented CCl4-induced (i) necrosis, inflammatory infiltration and up-regulation of α1(2)collagen, alpha-smooth muscle actin (α-SMA), platelet derived growth factor beta (PDGF-β) receptor and fibronectin mRNA expression; (ii) down-regulation of adipogenic gene, PPARγ and the up-regulation of epigenetic repressor gene, methyl CpG binding protein 2 (MeCP2) mRNA levels, suggesting that the anti-fibrogenic actions of Tβ4 involve the prevention of trans-differentiation of quiescent hepatic stellate cells into myo-fibroblasts largely by up-regulating PPARγ and by down-regulating MeCP2 genes. We therefore conclude that betaine and Tβ4 can effectively protect against alcoholic hepatosteatosis and hepatic fibrogenesis, respectively.

HDL cholesterol and cardiovascular outcomes: what is the evidence?

The relationship between low concentrations of high density lipoprotein cholesterol (HDL-C) and heightened risk for cardiovascular (CV) disease has been known for decades. Despite the consistent inverse relationship among epidemiological studies, the linkage between a residual low HDL-C among patients treated with statins and excess cardiovascular risk is less clearly established. Encouraging results from trials using niacin over the past 40 years have not been validated among more recent trials in patients taking contemporary anti-atherosclerotic therapy. Emerging evidence suggests that certain subsets of HDL particles may be more protective and/or more closely associated with CV disease than others, which may impact therapeutic benefits. Ongoing clinical trials will clarify whether raising HDL-C per se directly translates into a reduction in hard CV events. Until those results are available, the clinician is left with only weak evidence to support whether or not to target treatment of HDL-C with pharmacological therapy.

Sphingomyelin in high-density lipoproteins: structural role and biological function

High-density lipoprotein (HDL) levels are an inverse risk factor for cardiovascular diseases, and sphingomyelin (SM) is the second most abundant phospholipid component and the major sphingolipid in HDL. Considering the marked presence of SM, the present review has focused on the current knowledge about this phospholipid by addressing its variable distribution among HDL lipoparticles, how they acquire this phospholipid, and the important role that SM plays in regulating their fluidity and cholesterol efflux from different cells. In addition, plasma enzymes involved in HDL metabolism such as lecithin-cholesterol acyltransferase or phospholipid transfer protein are inhibited by HDL SM content. Likewise, HDL SM levels are influenced by dietary maneuvers (source of protein or fat), drugs (statins or diuretics) and modified in diseases such as diabetes, renal failure or Niemann-Pick disease. Furthermore, increased levels of HDL SM have been shown to be an inverse risk factor for coronary heart disease. The complexity of SM species, described using new lipidomic methodologies, and their distribution in different HDL particles under many experimental conditions are promising avenues for further research in the future.

Effects of ethanol intake on lipoproteins

These review discusses the effects of ethanol on lipoprotein levels and function as related to atherosclerosis and cardiovascular disease (CVD), with special emphasis on recent publications. Ethanol's effects on high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG), and other CVD risk factors recently have been explored. Other new data address genetic and demographic predictors and mechanisms of these responses. Not surprisingly, the results of some recent studies corroborate, whereas others differ from, earlier seemingly well-established findings. Prior and recent evidence shows favorable changes in HDL, other CVD risk factors, and CVD event rates with moderate, regular ethanol intake, and recent publications have explored the mechanisms of this relationship. Application of these findings in clinical practice remains problematic, however, due to the lack of randomized, controlled clinical trials of ethanol and due to the potential hazards of ethanol consumption.

Individual differences in hyperlipidemia and vitamin E status in response to chronic alcohol self-administration in cynomolgus monkeys

BACKGROUND

Chronic ethanol self-administration induces oxidative stress and exacerbates lipid peroxidation. α-Tocopherol is a potent lipid antioxidant and vitamin that is dependent upon lipoprotein transport for tissue delivery.

METHODS

To evaluate the extent to which vitamin E status is deranged by excessive alcohol consumption, monkeys voluntarily drinking ethanol (1.36 to 3.98 g/kg/d for 19 months, n = 11) were compared with nondrinkers (n = 5, control).

RESULTS

Three alcohol-drinking animals developed hyperlipidemia with plasma triglyceride levels (1.8 ± 0.9 mM) double those of normolipidemic (NL) drinkers (0.6 ± 0.2) and controls (0.6 ± 0.3, p < 0.05); elevated plasma cholesterol (3.6 ± 0.5 mM) compared with NL drinkers (2.3 ± 0.2, p < 0.05) and controls (2.9 ± 0.3); and lower plasma α-tocopherol per triglycerides (14 ± 6 mmol/mol) than controls (27 ± 8) and NL drinkers (23 ± 6, p < 0.05). Hyperlipidemic monkey liver α-tocopherol (47 ± 15 nmol/g) was lower than NL drinkers (65 ± 13) and controls (70 ± 15, p = 0.080), as was adipose α-tocopherol (84 ± 37 nmol/g) compared with controls (224 ± 118) and NL drinkers (285 ± 234, p < 0.05). Plasma apolipoprotein (apo) CIII increased compared to baseline at both 12 and 19 months in the normolipidemic (p = 0.0016 and p = 0.0028, respectively) and in the hyperlipidemic drinkers (p < 0.05 and p < 0.05, respectively). Plasma apo H concentrations at 19 months were elevated hyperlipidemics (p < 0.05) relative to concentrations in control animals. C-reactive protein (CRP), a marker of inflammation, was increased compared to baseline at both the 12- and 19-month time points in the normolipidemic (p = 0.005 and p = 0.0153, respectively) and hyperlipidemic drinkers (p = 0.016 and p = 0.0201, respectively).

CONCLUSION

A subset of alcohol-drinking monkeys showed a predisposition to alcohol-induced hyperlipidemia. The defect in lipid metabolism resulted in lower plasma α-tocopherol per triglycerides and depleted adipose tissue α-tocopherol, and thus decreased vitamin E status.

Effects of ethanol intake on lipoproteins and atherosclerosis

PURPOSE OF REVIEW

This article reviews published studies regarding effects of ethanol intake on lipoprotein levels and function as they relate to atherosclerosis, with special emphasis on recent publications in the past 2 years.

RECENT FINDINGS

Some recent studies have explored novel mechanisms of ethanol on atherogenesis via effects on HDL composition and function. Other studies have focused on changes in levels of LDL cholesterol (LDL-C), triglyceride, and other factors such as inflammatory markers C-reactive protein (CRP) and lipoprotein-associated phospholipase A2 (LpPLA2). Other areas of emphasis have been the effects within specific populations and between genders, as well as contributions of genetic polymorphisms in prediction of response to ethanol. Surprisingly, results of recent studies are often at odds with prior, seemingly well established findings.

SUMMARY

The association between moderate ethanol consumption and favorable changes in lipoproteins and lipoprotein-related factors in atherosclerosis continues to become better established with the publication of new studies in this field. Continued progress is being achieved in understanding the well established link between moderate intake and reduced risk of cardiovascular disease (CVD). Nevertheless, it remains difficult to implement these findings in clinical practice due to the ongoing lack of randomized, blinded clinical trial data, and the well known hazards of excess ethanol consumption.

HDL lipids and insulin resistance

There is renewed interest in high-density lipoproteins (HDLs) due to recent findings linking atherosclerosis to the formation of dysfunctional HDL. This article focuses on the universe of HDL lipids and their potential protective or proinflammatory roles in vascular disease and insulin resistance. HDL carries a wide array of lipids including sterols, triglycerides, fat-soluble vitamins, and a large number of phospholipids, including phosphatidylcholine, sphingomyelin, and ceramide with many biological functions. Ceramide has been implicated in the pathogenesis of insulin resistance and has many proinflammatory properties. In contrast, sphingosine-1-phosphate, which is transported mainly in HDL, has anti-inflammatory properties that may be atheroprotective and may account for some of the beneficial effects of HDL. However, the complexity of the HDL lipidome is only beginning to reveal itself. The emergence of new analytical technologies should rapidly increase our understanding of the function of HDL lipids and their role in disease states.

Elevated adiponectin serum levels in patients with chronic alcohol abuse rapidly decline during alcohol withdrawal

BACKGROUND

Adiponectin is a circulating protein with hepatoprotective effects.

AIMS

To study the relationship of excessive alcohol consumption and serum adiponectin levels (SAL).

PATIENTS AND METHODS

The SAL were determined in (i) heavy drinkers without advanced liver damage during the course of alcohol withdrawal, (ii) patients with chronic hepatitis C virus (HCV) infection, (iii) patients with alcohol-associated cirrhosis, and (iv) healthy volunteers that consumed excessive amounts of alcohol for only a short period of time. Further, primary human hepatocytes (PHH) and adipocytes were incubated in vitro with alcohol or serum of patients.

RESULTS

Patients with chronic alcohol consumption had significantly higher SAL than HCV-patients with comparable degrees of liver damage. In alcoholics, but not in HCV patients, SAL positively correlated with serum levels of aminotransferases. Further, SAL correlated with the amount of alcohol consumption but declined during the course of alcohol abstinence. After short-term excessive alcohol consumption SAL were not elevated in healthy individuals. Adiponectin mRNA was detectable in adipocytes but not in hepatocytes, and alcohol failed to induce adiponectin in both cell types. In contrast, serum of active drinkers induced adiponectin expression in adipocytes while serum from the same individuals collected after alcohol withdrawal had no effect.

CONCLUSIONS

Alcohol exhibits a specific effect on SAL that is dose and time dependent, and correlates with the degree of hepatic damage. Alcohol does not seem to affect adiponectin expression directly in adipocytes but potentially via mediators systemically released as a result of the chronic alcohol intake.

Diet, alcohol consumption, and serum lipid levels of the middle-aged and elderly in the Guangxi Bai Ku Yao and Han populations

Bai Ku Yao is an isolated subgroup of the Yao minority in China. The special customs and cultures including their clothing, intraethnic marriages, corn wine and rum intakes are still completely conserved to the present day. Little is known about the association of diet and alcohol consumption with serum lipid levels in this population. The aim of this study was to compare the differences in diet, alcohol consumption, and serum lipid levels of the middle-aged and elderly between the Guangxi Bai Ku Yao and Han populations. A total of 485 subjects of Bai Ku Yao and 501 participants of Han Chinese aged 40 and over were surveyed by a stratified randomized cluster sampling. Information on dietary intake and alcohol consumption was collected by standard questionnaires. Serum lipid levels were measured. Education level, height, weight, body mass index, waist circumference, blood pressure, hypertension, and total energy, fat, protein, dietary cholesterol, and salt intakes were lower in Bai Ku Yao than in Han (P < .05-.001), whereas physical activity level, carbohydrate, vegetal protein, and total dietary fiber intakes were higher in Bai Ku Yao than in Han (P < .001 for all). Serum total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein (Apo) A1, and Apo B levels were lower in Bai Ku Yao than in Han (P < .001 for all). The levels of triglyceride, HDL-C, Apo A1, and the ratio of Apo A1 to Apo B in Bai Ku Yao were higher, but the levels of LDL-C and Apo B were lower in drinkers than in nondrinkers. The levels of triglyceride, HDL-C, LDL-C, Apo A1, Apo B, and the ratio of Apo A1 to Apo B in Bai Ku Yao were also influenced by the amount of alcohol consumed (P < .05-.001). High-density lipoprotein cholesterol levels in Han were higher and LDL-C levels were lower in drinkers than in nondrinkers (P < .01 for each). Serum total cholesterol, HDL-C, and LDL-C levels in Han were also associated with the amount of alcohol consumed (P < .05-.001). The differences in the lipid levels between the two ethnic groups may partially attribute to the differences in dietary habits and alcohol consumption.