Moderate alcohol consumption increases cholesterol efflux mediated by ABCA1

Alcohol Consumption, High-Density Lipoprotein Particles and Subspecies, and Risk of Cardiovascular Disease: Findings from the PREVEND Prospective Study

The associations of HDL particle (HDL-P) and subspecies concentrations with alcohol consumption are unclear. We aimed to evaluate the interplay between alcohol consumption, HDL parameters and cardiovascular disease (CVD) risk. In the PREVEND study of 5151 participants (mean age, 53 years; 47.5% males), self-reported alcohol consumption and HDL-P and subspecies (small, medium, and large) by nuclear magnetic resonance spectroscopy were assessed. Hazard ratios (HRs) with 95% CIs for first CVD events were estimated. In multivariable linear regression analyses, increasing alcohol consumption increased HDL-C, HDL-P, large and medium HDL, HDL size, and HDL subspecies (H3P, H4P, H6 and H7) in a dose-dependent manner. During a median follow-up of 8.3 years, 323 first CVD events were recorded. Compared with abstainers, the multivariable adjusted HRs (95% CIs) of CVD for occasional to light, moderate, and heavy alcohol consumers were 0.72 (0.55-0.94), 0.74 (0.54-1.02), and 0.65 (0.38-1.09), respectively. These associations remained consistent on additional adjustment for each HDL parameter. For CVD, only HDL-C was associated with a statistically significant decreased risk of CVD in a fully adjusted analysis (HR 0.84, 95% CI 0.72-0.97 per 1 SD increment). For coronary heart disease, HDL-C, HDL-P, medium HDL, HDL size, and H4P showed inverse associations, whereas HDL-C and HDL size modestly increased stroke risk. Except for H6P, alcohol consumption did not modify the associations between HDL parameters and CVD risk. The addition of HDL-C, HDL size, or H4P to a CVD risk prediction model containing established risk factors improved risk discrimination. Increasing alcohol consumption is associated with increased HDL-C, HDL-P, large and medium HDL, HDL size, and some HDL subspecies. Associations of alcohol consumption with CVD are largely independent of HDL parameters. The associations of HDL parameters with incident CVD are generally not attenuated or modified by alcohol consumption.

Does Elevated High-Density Lipoprotein Cholesterol Protect Against Cardiovascular Disease?

High-density lipoprotein (HDL) contributes to reverse cholesterol transport, which is 1 of the main explanations for the described inverse association between HDL-cholesterol (HDL-C) and atherosclerotic cardiovascular disease (ASCVD) risk. However, efforts to therapeutically raise HDL-C levels with niacin, fibrates, or cholesteryl ester transfer protein inhibitors have not demonstrated a reduction in ASCVD events when compared with placebo among individuals treated with statins. Furthermore, mendelian randomization studies suggest that HDL-C is unlikely to be a direct biologic variable impacting ASCVD risk. More recently, observations from well-conducted epidemiologic studies have indicated a nonlinear U-shaped relationship between HDL-C and subclinical atherosclerosis, and that very high HDL-C (≥80 mg/dL in men, ≥100 mg/dL in women) is paradoxically associated with higher all-cause and ASCVD-related mortality. These observations suggest that HDL-C is not a universal protective factor for atherosclerosis. Thus, there are several opportunities for reframing the contribution of HDL-C to ASCVD risk and related clinical calculators. Here, we examine our growing understanding of HDL-C and its role in ASCVD risk assessment, treatment, and prevention. We discuss the biological functions of HDL-C and its normative values in relation to demographics and lifestyle markers. We then summarize original studies that observed a protective association between HDL-C and ASCVD risk and more recent evidence indicating an elevated ASCVD risk at very high HDL-C levels. Through this process, we advance the discussion regarding the future role of HDL-C in ASCVD risk assessment and identify knowledge gaps pertaining to the precise role of HDL-C in atherosclerosis and clinical ASCVD.

The Relationship of Alcohol Consumption and HDL Metabolism in the Multiethnic Dallas Heart Study

BACKGROUND

Small studies have suggested that moderate alcohol consumption increases HDL cholesterol (HDL-C) levels and cholesterol efflux capacity (CEC), a main anti-atherosclerotic HDL function.

OBJECTIVES

This study aimed to understand the degree to which alcohol intake is associated with various HDL markers in a large, multiethnic population cohort, the Dallas Heart Study (DHS), and whether alcohol modifies the link between HDL markers and atherosclerotic cardiovascular disease (ASCVD).

METHODS

Participants of the DHS were included if they had self-reported alcohol intake and CEC measurements (N=2,919). Alcohol intake was analyzed continuously (grams/week) and as an ordered categorical variable (never, past, light, moderate, heavy, and binge drinkers). HDL-C, CEC, HDL particle number (HDL-P), HDL particle size (HDL-size), and ApoA-I were the primary HDL measures.

RESULTS

After adjustment for confounding variables, increasing continuous measure of alcohol intake was associated with increased levels of all HDL markers. Moreover, as compared to moderate drinkers, light drinkers had decreased levels of the HDL markers.

CONCLUSION

In a large, multiethnic cohort, increased alcohol intake was associated with increased levels of multiple markers of HDL metabolism. However, the association of HDL markers with ASCVD risk as modified by alcohol consumption is unable to be determined in this low-risk cohort.

1-2 Drinks Per Day Affect Lipoprotein Composition after 3 Weeks-Results from a Cross-Over Pilot Intervention Trial in Healthy Adults Using Nuclear Magnetic Resonance-Measured Lipoproteins and Apolipoproteins

Alcohol consumption ranging from 1−2 drinks/day associates with a lower risk of coronary heart disease in some studies. The underlying mechanisms are unclear. The Metabolic Imprints of Alcoholic Beverages (MetAl) trial aimed to explore the short-term effects of moderate alcohol consumption on cardiovascular biomarkers. A 2 × 3-week cross-over single-blinded intervention trial investigating the effect of 1−2 drinks/day (~12−24 g) compared with abstention on 1H Nuclear Magnetic Resonance-measured main lipoproteins and subfractions was performed in 26 healthy adults. Volunteers were classified as occasional or habitual drinkers based on their habitual alcohol intakes (<2 or ≥2 drinks/week). Compared with abstention, 1−2 drinks/day increased HDL2a-C (p = 0.004), HDL3-C (p = 0.008), and HDL non-significantly (p = 0.19). Total apoA1 and apoA1 in HDL and its subfractions increased (p < 0.05). Novel findings were a decreased apoB/apoA1 ratio (p = 0.02), and increased HDL2a phospholipid content (p = 0.04). In women alone, the results were similar but attenuated, and LDL-P decreased. Thus, changes in apoA1- and HDL-related biomarkers occur within weeks in moderate drinkers. Compared with abstention, 1−2 drinks/day increased total apoA1 more strongly than HDL-C and increased the cholesterol, apoA1, and phospholipid content of several HDL subfractions. Whether this provides a cardiovascular benefit requires further study. Clinicaltrials.gov: NCT03384147.

Moderate alcohol consumption and lipoprotein subfractions: a systematic review of intervention and observational studies

CONTEXT

Moderate alcohol consumption is associated with decreased risk of cardiovascular disease (CVD) and improvement in cardiovascular risk markers, including lipoproteins and lipoprotein subfractions.

OBJECTIVE

To systematically review the relationship between moderate alcohol intake, lipoprotein subfractions, and related mechanisms.

DATA SOURCES

Following PRISMA, all human and ex vivo studies with an alcohol intake up to 60 g/d were included from 8 databases.

DATA EXTRACTION

A total of 17 478 studies were screened, and data were extracted from 37 intervention and 77 observational studies.

RESULTS

Alcohol intake was positively associated with all HDL subfractions. A few studies found lower levels of small LDLs, increased average LDL particle size, and nonlinear relationships to apolipoprotein B-containing lipoproteins. Cholesterol efflux capacity and paraoxonase activity were consistently increased. Several studies had unclear or high risk of bias, and heterogeneous laboratory methods restricted comparability between studies.

CONCLUSIONS

Up to 60 g/d alcohol can cause changes in lipoprotein subfractions and related mechanisms that could influence cardiovascular health.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. 98955.

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.

Dietary Strategies to Improve Cardiovascular Health: Focus on Increasing High-Density Lipoprotein Functionality

Cardiovascular disease is one of the leading causes of morbidity and mortality worldwide, with increasing incidence. A cornerstone of cardiovascular disease prevention is lifestyle modification through dietary changes to influence various risk factors such as obesity, hypertension and diabetes. The effects of diet on cardiovascular health are complex. Some dietary components and metabolites directly affect the composition and structure of high-density lipoproteins (HDL) and increase anti-inflammatory and vasoprotective properties. HDLs are composed of distinct subpopulations of particles of varying size and composition that have several dynamic and context-dependent functions. The identification of potential dietary components that improve HDL functionality is currently an important research goal. One of the best-studied diets for cardiovascular health is the Mediterranean diet, consisting of fish, olive oil, fruits, vegetables, whole grains, legumes/nuts, and moderate consumption of alcohol, most commonly red wine. The Mediterranean diet, especially when supplemented with extra virgin olive oil rich in phenolic compounds, has been shown to markedly improve metrics of HDL functionality and reduce the burden, or even prevent the development of cardiovascular disease. Particularly, the phenolic compounds of extra virgin olive oil seem to exert the significant positive effects on HDL function. Moreover, supplementation of anthocyanins as well as antioxidants such as lycopene or the omega-3 fatty acid eicosapentaenoic acid improve parameters of HDL function. In this review, we aim to highlight recent discoveries on beneficial dietary patterns as well as nutritional components and their effects on cardiovascular health, focusing on HDL function.

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.

A Common R219K Variant of ATP-Binding Cassette Transporter A1 Gene Alters Atherometabolic Traits in Pregnant Women With Gestational Diabetes Mellitus

BACKGROUND

ATP-binding cassette transporter A1 (ABCA1) has important roles in high-density lipoprotein (HDL) metabolism and reverse cholesterol transport, and is implicated in lipid-related disorders. Genetic variants are involved in the pathogenesis of gestational diabetes mellitus (GDM). The objective of this study was to investigate the association of rs2230806 (R219K), a single nucleotide polymorphism (SNP) in the lipid-related gene, with the risk of GDM and related traits.

METHODS

The SNP, rs2230806, was genotyped, and clinical and metabolic parameters were determined in 660 GDM patients and 1,097 control subjects. Genetic associations with related traits were also analyzed.

RESULTS

The genotype distributions were similar in GDM patients and normal controls. However, significant differences in the variables examined in the study subjects were noted across the three genotypes. The genotype at the rs2230806 polymorphism was significantly associated with HDL-cholesterol (HDL-C) levels and atherogenic index (AI) values in GDM patients and total cholesterol (TC) and low-density lipoprotein-cholesterol (LDL-C) levels in control subjects. Subgroup analysis showed that the polymorphism was associated with diastolic blood pressure, in addition to HDL-C levels and AI, in overweight/obese GDM patients, while it was associated with TC levels, AI, pre-pregnancy body mass index (BMI), and BMI at delivery in non-obese GDM patients. In addition, this polymorphism was associated with TC, LDL-C, and apoB levels in overweight/obese control subjects.

CONCLUSIONS

The rs2230806 polymorphism in the ABCA1 gene was associated with variations in atherometabolic traits in GDM patients, with characteristics of BMI dependency, but not with GDM. Our findings highlight a link between related phenotypes in women with GDM and genetic factors.

Interaction between high-density lipoproteins and inflammation: Function matters more than concentration!

High-density lipoprotein (HDL) plays an important role in lipid metabolism and especially contributes to the reverse cholesterol transport pathway. Over recent years it has become clear that the effect of HDL on immune-modulation is not only dependent on HDL concentration but also and perhaps even more so on HDL function. This review will provide a concise general introduction to HDL followed by an overview of post-translational modifications of HDL and a detailed overview of the role of HDL in inflammatory diseases. The clinical potential of HDL and its main apolipoprotein constituent, apoA-I, is also addressed in this context. Finally, some conclusions and remarks that are important for future HDL-based research and further development of HDL-focused therapies are discussed.

Impact of Red Wine Consumption on Cardiovascular Health

BACKGROUND

The devastating effects of heavy alcohol drinking have been long time recognized. In the last decades, potential benefits of modest red wine drinking were suggested. In European countries in which red wide intake is not negligible (such as France), the association between cholesterol and cardiovascular (CV) risk was less evident, suggesting the action of some protective molecules in red wine or other foods and drinks.

METHODS

This narrative review is based on the material searched for and obtained via PubMed up to May 2016. The search terms we used were: "red wine, cardiovascular, alcohol" in combination with "polyphenols, heart failure, infarction".

RESULTS

Epidemiological and mechanistic evidence of a J-shaped relationship between red wine intake and CV risk further supported the "French paradox". Specific components of red wine both in vitro and in animal models were discovered. Polyphenols and especially resveratrol largely contribute to CV prevention mainly through antioxidant properties. They exert beneficial effects on endothelial dysfunction and hypertension, dyslipidemia, metabolic diseases, thus reducing the risk of adverse CV events such as myocardial infarction ischemic stroke and heart failure. Of interest, recent studies pointed out the role of ethanol itself as a potential cardioprotective agent, but a clear epidemiological evidence is still missing. The aim of this narrative review is to update current knowledge on the intracellular mechanism underlying the cardioprotective effects of polyphenols and ethanol. Furthermore, we summarized the results of epidemiological studies, emphasizing their methodological criticisms and the need for randomized clinical trials able to clarify the potential role of red wine consumption in reducing CV risk.

CONCLUSION

Caution in avowing underestimation of the global burden of alcohol-related diseases was particularly used.

Consumption of Alcoholic Beverages and the Prevalence of Metabolic Syndrome and Its Components

The relationship between alcohol consumption and the prevalence of metabolic syndrome is not consistent and may vary between populations, depending on age, sex, ethnicity, cultural traditions and lifestyle. We have hypothesized that moderate alcohol consumption will be associated with the lowest risk of the syndrome. The aim of the present study is to examine the relationship between the current consumption of alcohol and the prevalence of metabolic syndrome and its components. The research material includes data obtained from 12,285 men and women, in the age range of 37–66 years. Multiple logistic regression was used in the statistical analysis. Metabolic syndrome (MetS) was defined according to the International Diabetes Federation. In men, a current consumption of >30 g of alcohol/day was significantly associated with a higher risk of metabolic syndrome (OR = 1.73, 95% CI = 1.25–2.39), high blood pressure (OR = 2.76, 95% CI = 1.64–4.65), elevated glucose concentration (OR = 1.70, 95% CI = 1.24–2.32), and abdominal obesity (OR = 1.77; 95% CI = 1.07–2.92). In women, the consumption from 10.1 to 15.0 g of alcohol was associated only with a higher risk of abnormal glucose concentration (OR = 1.65; 95% CI = 1.14–2.38.) In both sexes, current alcohol consumption was associated with higher high-density lipoproteins (HDL)-cholesterol concentration (p < 0.05). No relationship was found between alcohol consumption and triglyceride concentration. It is difficult to formulate unequivocal recommendations regarding alcohol intake in MetS prophylaxis due to its different association with particular MetS components. In order to explain the causal relationship between alcohol consumption and MetS and its components, prospective studies are necessary.

Moderate Beer Intake and Cardiovascular Health in Overweight Individuals

Consistent epidemiological evidence indicates that low-to-moderate alcohol consumption is inversely associated with cardiovascular event presentation, while high levels of alcohol intake are associated to increased cardiovascular risk. Little is known on the effects of moderate beer intake in the metabolic syndrome. The aim of this study is to investigate the effects of moderate and regular daily intake of beer with meals in overweight (body mass index (BMI) of 28–29.9 kg/m²) or obese class 1 (BMI of 30–35 kg/m²) individuals without other cardiovascular risk factors (dyslipidemia, type 2-diabetes, hypertension) focusing on the effects related to changes in weight, in lipoproteins and vascular endothelial function. We have performed an open, prospective two-arms longitudinal crossover study to investigate the effects associated with regular consumption (four week) of alcohol-free-beer (0 g alcohol/day) or traditional-beer (30 g alcohol/day in men and 15 g alcohol/day in women) on anthropometrical and biochemical parameters, liver and kidney function biomarkers, and vascular endothelial function. After four-week intervention with traditional and/or alcohol-free beer, BMI did not show any significant change and values for liver and kidney functions were within the normal levels. Moderate traditional beer intake did not affect lipid levels—however it significantly increased the antioxidant capacity of high density lipoprotein (HDL). In addition, apoB-depleted serum (after the four-week intervention period) showed a higher potential to promote cholesterol efflux from macrophages. Beer consumption did not induce vascular endothelial dysfunction or stiffness. In summary, our results based on a 12-week prospective study provide evidence that moderate intake of beer (traditional and alcohol-free) does not exert vascular detrimental effects nor increases body weight in obese healthy individuals. In contrast, moderate intake of beer increases the anti-oxidative properties of HDL and facilitates cholesterol efflux, which may prevent lipid deposition in the vessel wall.

Large-Scale Analysis of Determinants, Stability, and Heritability of High-Density Lipoprotein Cholesterol Efflux Capacity

Supplemental Digital Content is available in the text.

Objective—

Cholesterol efflux capacity (CEC) has emerged as a biomarker of coronary artery disease risk beyond plasma high-density lipoprotein (HDL) cholesterol (HDL-C) level. However, the determinants of CEC are incompletely characterized. We undertook a large-scale family-based population study to identify clinical, biochemical, and HDL particle parameter determinants of CEC, characterize reasons for the discordancy with HDL-C, quantify its heritability, and assess its stability over 10 to 12 years.

Approaches and Results—

CEC was quantified in 1988 individuals from the GRAPHIC (Genetic Regulation of Arterial Pressure of Humans in the Community) cohort, comprising individuals from 2 generations from 520 white nuclear families. Serum lipid and lipoprotein levels were determined by ultracentrifugation or nuclear magnetic resonance and HDL particle size and number quantified by nuclear magnetic resonance. Ninety unrelated individuals had repeat CEC measurements in samples collected after 10 to 12 years. CEC was positively correlated with HDL-C (R=0.62; P<0.0001). Among clinical and biochemical parameters, age, systolic blood pressure, alcohol consumption, serum albumin, triglycerides, phospholipids, and lipoprotein(a) were independently associated with CEC. Among HDL particle parameters, HDL particle number, particle size, and apolipoprotein A-II level were independently associated with CEC. Serum triglyceride level partially explained discordancy between CEC and HDL-C. CEC measurements in samples collected 10 to 12 years apart were strongly correlated (r=0.73; P<0.0001). Heritability of CEC was 0.31 (P=3.89×10⁻¹⁴) without adjustment for HDL-C and 0.13 (P=1.44×10⁻³) with adjustment.

Conclusions—

CEC is a stable trait over time, is influenced by specific clinical, serum, and HDL particle parameters factors beyond HDL-C, can be maintained in persons with a low plasma HDL-C by elevated serum triglyceride level, and is modestly independently heritable.

Dietary Strategies and Novel Pharmaceutical Approaches Targeting Serum ApoA-I Metabolism: A Systematic Overview

The incidence of CHD is still increasing, which underscores the need for new preventive and therapeutic approaches to decrease CHD risk. In this respect, increasing apoA-I concentrations may be a promising approach, especially through increasing apoA-I synthesis. This review first provides insight into current knowledge on apoA-I production, clearance, and degradation, followed by a systematic review of dietary and novel pharmacological approaches to target apoA-I metabolism. For this, a systematic search was performed to identify randomized controlled intervention studies that examined effects of whole foods and (non)nutrients on apoA-I metabolism. In addition, novel pharmacological approaches were searched for, which were specifically developed to target apoA-I metabolism. We conclude that both dietary components and pharmacological approaches can be used to increase apoA-I concentrations or functionality. For the dietary components in particular, more knowledge about the underlying mechanisms is necessary, as increasing apoA-I per se does not necessarily translate into a reduced CHD risk.

Moderate Alcohol Consumption and Chronic Disease: The Case for a Long-Term Trial

Drinking within recommended limits is highly prevalent in much of the world, and strong epidemiological associations exist between moderate alcohol consumption and risk of several major chronic diseases, including coronary heart disease, diabetes, and breast cancer. In many cases, plausible biological mediators for these associations have been identified in randomized trials, but gold standard evidence that moderate drinking causes or prevents any chronic disease remains elusive and important concerns about available evidence have been raised. Although long-term randomized trials to test the observed associations have been termed impossible, clinical investigators have now successfully completed randomized trials of complex nutritional interventions in a variety of settings, along with trials of alcohol consumption itself of up to 2 years duration. The successful completion of these trials suggests that objections to the execution of a full-scale, long-term clinical trial of moderate drinking on chronic disease are increasingly untenable. We present potential lessons learned for such a trial and discuss key features to maximize its feasibility and value.

Mendelian randomization analysis in three Japanese populations supports a causal role of alcohol consumption in lowering low-density lipid cholesterol levels and particle numbers

BACKGROUND AND AIMS

While alcohol consumption is known to increase plasma high-density lipoprotein (HDL) cholesterol levels, its relationship with low-density lipoprotein (LDL) cholesterol levels is unclear. Aldehyde dehydrogenase 2 (ALDH2) is a rate-controlling enzyme in alcohol metabolism, but a large number of Japanese people have the inactive allele. Here, we conducted a Mendelian randomization analysis using the ALDH2 genotype to clarify a causal role of alcohol on circulating cholesterol levels and lipoprotein particle numbers.

METHODS

This study was conducted in three independent general Japanese populations (men, n = 2289; women, n = 1940; mean age 63.3 ± 11.2 years). Alcohol consumption was assessed using a questionnaire. Lipoprotein particle numbers were determined by nuclear magnetic resonance spectroscopy.

RESULTS

Alcohol consumption increased linearly in proportion to the number of subjects carrying the enzymatically active *1 allele in men (p < 0.001). The *1 allele was also positively associated with HDL cholesterol level (adjusted mean ± standard error, *1*1: 60 ± 0.5, *1*2: 56 ± 0.6, *2*2: 55 ± 1.3 mg/dl, p < 0.001) and inversely associated with LDL cholesterol level (116 ± 0.9, 124 ± 1.1, 130 ± 2.6 mg/dl, p < 0.001). The *1 allele was also positively associated with HDL particle numbers (per-allele: 2.60 ± 0.32 μmol/l, p < 0.001) and inversely associated with LDL particle numbers (-67.8 ± 19.6 nmol/l, p = 0.001). Additional Mendelian randomization analysis failed to clarify the involvement of cholesteryl ester transfer protein in alcohol-related changes in lipoprotein cholesterol levels. No significant association was observed in women, presumably due to their small amount of alcohol intake.

CONCLUSIONS

Alcohol consumption has a causal role in not only increasing HDL cholesterol levels but also decreasing LDL cholesterol levels and particle numbers.

Causal Role of Alcohol Consumption in an Improved Lipid Profile: The Atherosclerosis Risk in Communities (ARIC) Study

INTRODUCTION

Health benefits of low-to-moderate alcohol consumption may operate through an improved lipid profile. A Mendelian randomization (MR) approach was used to examine whether alcohol consumption causally affects lipid levels.

METHODS

This analysis involved 10,893 European Americans (EA) from the Atherosclerosis Risk in Communities (ARIC) study. Common and rare variants in alcohol dehydrogenase and acetaldehyde dehydrogenase genes were evaluated for MR assumptions. Five variants, residing in the ADH1B, ADH1C, and ADH4 genes, were selected as genetic instruments and were combined into an unweighted genetic score. Triglycerides (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-c) and its subfractions (HDL2-c and HDL3-c), low-density lipoprotein cholesterol (LDL-c), small dense LDL-c (sdLDL-c), apolipoprotein B (apoB), and lipoprotein (a) (Lp(a)) levels were analyzed.

RESULTS

Alcohol consumption significantly increased HDL2-c and reduced TG, total cholesterol, LDL-c, sdLDL-c, and apoB levels. For each of these lipids a non-linear trend was observed. Compared to the first quartile of alcohol consumption, the third quartile had a 12.3% lower level of TG (p < 0.001), a 7.71 mg/dL lower level of total cholesterol (p = 0.007), a 10.3% higher level of HDL2-c (p = 0.007), a 6.87 mg/dL lower level of LDL-c (p = 0.012), a 7.4% lower level of sdLDL-c (p = 0.037), and a 3.5% lower level of apoB (p = 0.058, poverall = 0.022).

CONCLUSIONS

This study supports the causal role of regular low-to-moderate alcohol consumption in increasing HDL2-c, reducing TG, total cholesterol, and LDL-c, and provides evidence for the novel finding that low-to-moderate consumption of alcohol reduces apoB and sdLDL-c levels among EA. However, given the nonlinearity of the effect of alcohol consumption, even within the range of low-to-moderate drinking, increased consumption does not always result in a larger benefit.

Light-to-moderate drinking and incident heart failure--the Norwegian HUNT study

BACKGROUND

We analyzed the association between light-to-moderate alcohol intake and the risk of heart failure (HF).

METHODS AND RESULTS

We studied 60,665 individuals free of HF who provided information on alcohol consumption in a population-based cohort study conducted in 1995-97 in Norway. Sociodemographic factors, cardiovascular risk factors and common chronic disorders were assessed by questionnaires and/or by a clinical examination. The cohort was followed for a first HF event for an average of 11.2 ± 3.0 years. Mean alcohol consumption was 2.95 ± 4.5 g/day; 1588 HF cases occurred during follow-up. The quantity of alcohol consumption was inversely associated with incident HF in this low-drinking population. The risk was lowest for consumption over three but less than six drinks/week; the multivariate hazard ratio when comparing this category to non-drinkers was 0.67 (95% CI: 0.50-0.92). Among problem drinkers based on CAGE questionnaires, total consumption showed no favorable association with HF, even when overall consumption was otherwise moderate. Excluding former drinkers and controlling for common chronic diseases had minimal effect on these associations. Frequent alcohol consumption, i.e. more than five times/month, was associated with the lowest HF risk; the adjusted hazard ratio comparing this group to alcohol intake less than once/month was 0.83 (95% CI: 0.68-1.03). We found no evidence for a differential effect according to beverage type, nor that the competing risks of death from other causes modified the association.

CONCLUSIONS

Frequent light-to-moderate alcohol consumption without problem drinking was associated with a lower HF risk in this population characterized by a low average alcohol intake.

High-Density Lipoprotein Function Measurement in Human Studies: Focus on Cholesterol Efflux Capacity

A low plasma level of high-density lipoprotein (HDL) cholesterol (HDL-C) is a major risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). However, several observations have highlighted the shortcomings of using cholesterol content as the sole reflection of HDL metabolism. In particular, several large randomized controlled trials of extended release niacin and cholesteryl-ester transfer protein (CETP) inhibitors on background statin therapy have failed to show improvement in ASCVD outcomes despite significant increases in HDL-C. Reverse cholesterol transport (RCT) is the principal HDL function that impacts macrophage foam cell formation and other functions such as endothelial activation of endothelial nitric oxide synthase, monocyte adhesion, and platelet aggregation. Cholesterol efflux from macrophages to plasma/serum reflects the first critical step of RCT and is considered a key anti-atherosclerotic function of HDL. Whether this function is operative in humans remains to be seen, but recent studies assessing cholesterol efflux in humans suggest that the cholesterol efflux capacity (CEC) of human plasma or serum is a potent marker of ASCVD risk. This review describes the methodology of measuring CEC ex vivo from human samples and the findings to date linking CEC to human disease. Studies to date confirm that CEC can be reliably measured using stored human blood samples as cholesterol acceptors and suggest that CEC may be a promising new biomarker for atherosclerotic and metabolic diseases. Further studies are needed to standardize measurements and clarify the role CEC may play in predicting risk of developing disease and response to therapies.

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.

Dietary approaches to improving atheroprotective HDL functions

High-density lipoproteins (HDL) are known to protect against cardiovascular disease (CVD). In addition to facilitating reverse cholesterol transport to remove excess lipids from the body - including atherosclerotic plaques - HDL exhibits antioxidant, anti-inflammatory, vasodilatory, and antithrombotic activities. Together, these properties contribute to the overall atheroprotective nature of HDL. However, similar to many other physiological pathways, these HDL parameters are known to become dysregulated in conditions of metabolic disease. Further, research suggests these alternative HDL properties may be regulated independently of blood HDL-cholesterol (HDL-C) levels, and must therefore be considered when designing HDL-targeted therapies. To date, a number of dietary strategies have been investigated to assess the effect of dietary components on functional properties of HDL beyond HDL-C. This review will highlight the bioactive nutrients, functional foods, and dietary programs known to modulate HDL function as a means of reducing CVD.

High-density lipoprotein cholesterol raising: does it matter?

PURPOSE OF REVIEW

Cardiovascular disease (CVD) is the leading cause of morbidity and premature mortality in Europe and the United States, and is increasingly common in developing countries. High-density lipoprotein cholesterol (HDL-C) is an independent risk factor for CVD and is superior to low-density lipoprotein cholesterol (LDL-C) as a predictor of cardiovascular events. The residual risk conferred by low HDL-C in patients with a satisfactory LDL-C was recently highlighted by the European Atherosclerosis Society. Despite the lack of randomized controlled trials, it has been suggested that raising the level of HDL-C should be considered as a therapeutic strategy in high-risk patients because of the strong epidemiological evidence, compelling biological plausibility, and both experimental and clinical research supporting its cardioprotective effects.

RECENT FINDINGS

Three recent large randomized clinical trials investigating the effect of HDL-C raising with niacin and dalcetrapib in statin-treated patients failed to demonstrate an improvement in cardiovascular outcomes.

SUMMARY

There is evidence to support the view that HDL functionality and the mechanism by which a therapeutic agent raises HDL-C are more important than plasma HDL-C levels. Future therapeutic agents will be required to improve this functionality rather than simply raising the cholesterol cargo.

Effect of combined mulberry leaf and fruit extract on liver and skin cholesterol transporters in high fat diet-induced obese mice

Obesity is an epidemic disease characterized by an increased inflammatory state and chronic oxidative stress with high levels of pro-inflammatory cytokines and lipid peroxidation. Moreover, obesity alters cholesterol metabolism with increases in low-density lipoprotein (LDL) cholesterols and triglycerides and decreases in high-density lipoprotein (HDL) cholesterols. It has been shown that mulberry leaf and fruit ameliorated hyperglycemic and hyperlipidemic conditions in obese and diabetic subjects. We hypothesized that supplementation with mulberry leaf combined with mulberry fruit (MLFE) ameliorate cholesterol transfer proteins accompanied by reduction of oxidative stress in the high fat diet induced obesity. Mice were fed control diet (CON) or high fat diet (HF) for 9 weeks. After obesity was induced, the mice were administered either the HF or the HF with combination of equal amount of mulberry leaf and fruit extract (MLFE) at 500mg/kg/day by gavage for 12 weeks. MLFE treatment ameliorated HF induced oxidative stress demonstrated by 4-hydroxynonenal (4-HNE) and modulated the expression of 2 key proteins involved in cholesterol transfer such as scavenger receptor class B type 1 (SR-B1) and ATP-binding cassette transporter A1 (ABCA1) in the HF treated animals. This effect was mainly noted in liver tissue rather than in cutaneous tissue. Collectively, this study demonstrated that MLFE treatment has beneficial effects on the modulation of high fat diet-induced oxidative stress and on the regulation of cholesterol transporters. These results suggest that MLFE might be a beneficial substance for conventional therapies to treat obesity and its complications.

Dietary strategies to reduce metabolic syndrome

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities characterized by central obesity, dyslipidemias, hypertension, high fasting glucose, chronic low-grade inflammation and oxidative stress. This condition has become an increasing problem in our society where about 34 % of adults are diagnosed with MetS. In parallel with the adult situation, a significant number of children present lipid abnormalities and insulin resistance, which can be used as markers of MetS in the pediatric population. Changes in lifestyle including healthy dietary regimens and increased physical activity should be the first lines of therapy to decrease MetS. In this article, we present the most recent information on successful dietary modifications that can reduce the parameters associated with MetS. Successful dietary strategies include energy restriction and weight loss, manipulation of dietary macronutrients--either through restriction of carbohydrates, fat, or enrichment in beneficial fatty acids, incorporation of functional foods and bioactive nutrients, and adherence to dietary and lifestyle patterns such the Mediterranean diet and diet/exercise regimens. Together, the recent findings presented in this review serve as evidence to support the therapeutic treatment of MetS through diet.

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.

Alcohol and the heart: to abstain or not to abstain?

Alcohol has been consumed by most societies over the last 7000 years. Abraham Lincoln said "It has long been recognized that the problems with alcohol relate not to the use of a bad thing, but to the abuse of a good thing." Light to moderate alcohol consumption reduces the incidence of coronary heart disease (CHD), ischemic stroke, peripheral arterial disease, CHD mortality, and all-cause mortality, especially in the western populations. However, heavy alcohol consumption is detrimental causing cardiomyopathy, cardiac arrhythmias, hepatic cirrhosis, pancreatitis, and hemorrhagic stroke. In this article, we review the effects of alcohol on CHD, individual cardiovascular risk factors, cardiomyopathy, and cardiac arrhythmias, including the most recent evidence of the effects of alcohol on CHD.

Deleterious impact of elaidic fatty acid on ABCA1-mediated cholesterol efflux from mouse and human macrophages

Consumption of trans fatty acids (TFA) increase cardiovascular risk more than do saturated FA, but the mechanisms explaining their atherogenicity are still unclear. We investigated the impact of membrane incorporation of TFA on cholesterol efflux by exposing J774 mouse macrophages or human monocyte-derived macrophages (HMDM) to media enriched or not (standard medium) with industrially produced elaidic (trans-9 18:1) acid, naturally produced vaccenic (trans-11 18:1) acid (34 h, 70 μM) or palmitic acid. In J774 macrophages, elaidic and palmitic acid, but not vaccenic acid, reduced ABCA1-mediated efflux by ~23% without affecting aqueous diffusion, SR-BI or ABCG1-mediated pathways, and this effect was maintained in cholesterol-loaded cells. The impact of elaidic acid on the ABCA1 pathway was weaker in cholesterol-normal HMDM, but elaidic acid induced a strong reduction of ABCA1-mediated efflux in cholesterol-loaded cells (-36%). In J774 cells, the FA supplies had no impact on cellular free cholesterol or cholesteryl ester masses, the abundance of ABCA1 mRNA or the total and plasma membrane ABCA1 protein content. Conversely, TFA or palmitic acid incorporation induced strong modifications of the membrane FA composition with a decrease in the ratio of (cis-monounsaturated FA+polyunsaturated FA):(saturated FA+TFA), with elaidic and vaccenic acids representing each 20% and 13% of the total FA composition, respectively. Moreover, we demonstrated that cellular ATP was required for the effect of elaidic acid, suggesting that it contributes to atherogenesis by impairing ABCA1-mediated cholesterol efflux in macrophages, likely by decreasing the membrane fluidity, which could thereby reduce ATPase activity and the function of the transporter.

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.

Induction of heme oxygenase-1 by whisky congeners in human endothelial cells

It is expected that the production of the cytoprotective heme oxygenase-1 (HO-1) protein in endothelial cells would reduce severity of vascular injuries, while phenolic compounds are known to induce HO-1 mRNA and protein in various cells. We investigated the activation of HO-1 by whisky, which contains various phenolic substances. The congeners of whisky stored from 4 to 18 y in oak barrels were shown to induce an increase of HO-1 protein in human umbilical vein endothelial cells, while those of freshly distilled whisky spirit exhibited no activity. To determine the compounds with potent HO-1-inducing activity among the whisky congeners, several chemicals that had been reported to exist in whisky or oak barrels were screened, and coniferyl aldehyde and sinapyl aldehyde showed the activity. Thus, compounds that emerged in whisky during barrel storage induced cytoprotective protein, HO-1, in human endothelial cells.

No interaction between alcohol consumption and HDL-related genes on HDL cholesterol levels

OBJECTIVE

To assess the relationships and possible interactions between polymorphisms related to HDL levels and alcohol consumption.

METHODS

Cross-sectional population-based study including 2863 women and 2546 men aged 35-75 years (CoLaus study). Alcohol intake was assessed by the reported alcohol consumption of the last 7 days. Nineteen candidate genes known to influence HDL levels were studied.

RESULTS

Alcohol consumption increased HDL cholesterol levels in both genders. After multivariate adjustment for gender, age, body mass index, smoking, hypolipidaemic drug treatment, physical activity and alcohol consumption, APOA5, CETP, LIPC and LPL gene polymorphisms were significantly (10(-5) threshold) related with HDL cholesterol levels, while no genexalcohol intake interaction was found for all SNPs studied. ABCA1 polymorphisms were related to HDL cholesterol levels on bivariate analysis but the relationship was no longer significant after multivariate analysis.

CONCLUSION

Our data confirm the association of alcohol consumption and of APOA5, CETP, LIPC and LPL gene polymorphisms with HDL cholesterol levels. Conversely, no genexalcohol consumption interactions were found, suggesting that the effect of alcohol consumption on HDL cholesterol levels is not mediated via a modulation of HDL related genes.

Anthocyanin supplementation improves serum LDL- and HDL-cholesterol concentrations associated with the inhibition of cholesteryl ester transfer protein in dyslipidemic subjects

BACKGROUND

Anthocyanins have been shown to exert benefits on the lipid profile in many animal models. Whether these molecules have similar beneficial effects in humans is currently unknown.

OBJECTIVE

The objective was to investigate the effects of berry-derived anthocyanin supplements on the serum lipid profile in dyslipidemic patients.

DESIGN

A total of 120 dyslipidemic subjects (age 40-65 y) were given 160 mg anthocyanins twice daily or placebo for 12 wk in a double-blind, randomized, placebo-controlled trial.

RESULTS

Anthocyanin consumption increased HDL-cholesterol concentrations (13.7% and 2.8% in the anthocyanin and placebo groups, respectively; P < 0.001) and decreased LDL-cholesterol concentrations (13.6% and -0.6% in the anthocyanin and placebo groups, respectively; P < 0.001). Cellular cholesterol efflux to serum increased more in the anthocyanin group than in the placebo group (20.0% and 0.2%, respectively; P < 0.001). Anthocyanin supplementation decreased the mass and activity of plasma cholesteryl ester transfer protein (CETP) (10.4% and 6.3%, respectively, in the anthocyanin group and -3.5% and 1.1%, respectively, in the placebo group; P < 0.001). In the anthocyanin group, the change in HDL cholesterol was negatively correlated with the change in CETP activity (r(s) = -0.330). The change in LDL cholesterol was positively correlated with the change in CETP mass (r(s) = 0.354). The change in cellular cholesterol efflux to serum was positively correlated with the change in HDL cholesterol (r(s) = 0.485). In vitro, cyanidin 3-O-beta-glucosides dose-dependently lowered CETP activity in human HepG2 cells.

CONCLUSIONS

Anthocyanin supplementation in humans improves LDL- and HDL-cholesterol concentrations and enhances cellular cholesterol efflux to serum. These benefits may be due to the inhibition of CETP.

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.

Moderate alcohol consumption and lipoprotein-associated phospholipase A2 activity

BACKGROUND AND AIMS

To investigate the effect of moderate alcohol consumption on lipoprotein-associated phospholipase A2 activity, markers of inflammation and oxidative stress and whether these effects are modified by BMI.

METHODS AND RESULTS

Eleven lean (BMI: 18.5-25 kg/m(2)) and 9 overweight (BMI>27 kg/m(2)) men participated in a randomized controlled crossover trial. After consuming 3 cans of beer (40 g ethanol) or alcohol-free beer daily during 3 weeks, fasting blood samples were taken. HDL cholesterol increased by 18.2% (p<0.001) after beer compared to alcohol-free beer, while LDL cholesterol decreased by 7.8% (p=0.008). Lipoprotein-associated phospholipase A2 activity was not different (p=0.23) between beer (47.5+/-0.8) and alcohol-free beer (48.9+/-0.8). High-sensitive C-reactive protein was unaffected, but urinary isoprostanes tended to increase (p=0.09) after beer (114.0+/-6.9) compared to alcohol-free beer (96.9+/-6.5). An interaction between BMI and treatment (p<0.05) on liver enzymes was observed, indicating an increase of liver enzymes after moderate alcohol consumption in overweight men only.

CONCLUSION

Despite profound effects on HDL and LDL cholesterol, moderate alcohol consumption did not affect lipoprotein-associated phospholipase A2 activity. Liver enzymes increased after alcohol consumption in overweight men only, suggesting a less favorable response to moderate alcohol consumption in overweight people.

Cytochrome P450 and gene activation--from pharmacology to cholesterol elimination and regression of atherosclerosis

BACKGROUND

Lipoproteins are closely associated with the atherosclerotic vascular process. Elevated levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein AI (apo AI) in plasma indicate a low probability of coronary heart disease (CHD) together with enhanced longevity, and elevated levels of low-density lipoprotein-cholesterol (LDL-C) and apo B indicate an increased risk of CHD and death. Studies linking gene activation and the induction of cytochrome P450 with elevated plasma levels of apo AI and HDL-C and lowered plasma levels of LDL-C presented a new potential approach to prevent and treat atherosclerotic disease.

OBJECTIVE AND METHODS

This is a review aimed at clarifying the effects of P450-enzymes and gene activation on cholesterol homeostasis, the atherosclerotic vascular process, prevention and regression of atherosclerosis and the manifestation of atherosclerotic disease, particularly CHD, the leading cause of death in the world.

RESULTS

P450-enzymes maintain cellular cholesterol homeostasis. They respond to cholesterol accumulation by enhancing the generation of hydroxycholesterols (oxysterols) and activating cholesterol-eliminating mechanisms. The CYP7A1, CYP27A1, CYP46A1 and CYP3A4 enzymes generate major oxysterols that enter the circulation. The oxysterols activate-via nuclear receptors-ATP-binding cassette (ABC) A1 and other genes, leading to the elimination of excess cholesterol and protecting arteries from atherosclerosis. Several drugs and nonpharmacologic compounds are ligands for the liver X receptor, pregnane X receptor and other receptors, activate P450 and other genes involved in cholesterol elimination, prevent or regress atherosclerosis and reduce cardiovascular events.

CONCLUSIONS

P450-enzymes are essential in the physiological maintenance of cholesterol balance. They activate mechanisms which eliminate excess cholesterol and counteract the atherosclerotic process. Several drugs and nonpharmacologic compounds induce P450 and other genes, prevent or regress atherosclerosis and reduce the occurrence of non-fatal and fatal CHD and other atherosclerotic diseases.

Replacement of dietary saturated FAs by PUFAs in diet and reverse cholesterol transport

Dietary intervention is the first and usually successful approach in the treatment of high LDL cholesterol (LDL-C) concentration, but it is frequently accompanied by a decrease in HDL concentration. We studied 14 male volunteers on two different diets, high saturated fatty acid (SFA) and high PUFA, in a crossover design to test whether a decrease in HDL can affect reverse cholesterol transport from relabeled macrophages. A significant decrease of LDL-C (in mmol/l) after a PUFA diet compared with an SFA diet from 3.15 +/- 0.65 to 2.80 +/- 0.56 (P < 0.01) was accompanied by a significant decrease of HDL cholesterol (HDL-C) (in mmol/l) from 1.21 +/- 0.30 to 1.10 +/- 0.32 (P < 0.05). These changes did not affect cholesterol efflux (CHE) from macrophages (9.74 +/- 1.46% vs. 9.53 +/- 1.41%). There was no correlation between individual changes of HDL-C and changes of CHE. It is concluded that the decrease of HDL-C after successful dietary intervention of LDL-C is not accompanied by a decrease of CHE.

Vascular compliance in the cardiometabolic syndrome

Elevated systolic blood pressure and increased pulse pressure are important predictors of vascular stiffening (compliance), left ventricular hypertrophy, coronary heart disease, heart failure, stroke, vascular dementia, and chronic kidney disease. Advances in noninvasive methods that measure arterial stiffness have led to increased understanding of the mechanisms underlying vascular dysfunction and the development of associated risk factors. The ability to detect and monitor changes in the physical properties of arteries has the potential to allow early interventions that may prevent disease or attenuate its progression. In this paper, the authors briefly review the various methods available to measure vascular compliance and review pathologic processes that lead to insulin resistance, endothelial dysfunction, inflammation, and sympathetic activation, all of which may contribute to increased arterial stiffness in the cardiometabolic syndrome. Strategies to improve vascular compliance are also discussed.

Glycemic effects of moderate alcohol intake among patients with type 2 diabetes: a multicenter, randomized, clinical intervention trial

OBJECTIVE

In a randomized controlled trial, we assessed the effect of daily moderate alcohol intake on glycemic control in the fasting and postprandial states in patients with type 2 diabetes who previously had abstained from alcohol.

RESEARCH DESIGN AND METHODS

We randomly assigned 109 patients (41-74 years old) with established type 2 diabetes who abstained from alcohol to receive 150 ml wine (13 g alcohol) or nonalcoholic diet beer (control) each day during a 3-month multicenter trial. The beverages were consumed during dinner. Diet and alcohol consumption were monitored.

RESULTS

During the intervention, 17% of participants (12% from the alcohol group) dropped out, leaving 91 who completed the trial. Within the alcohol group, fasting plasma glucose (FPG) decreased from 139.6 +/- 41 to 118.0 +/- 32.5 mg/dl after 3 months compared with 136.7 +/- 15.4 to 138.6 +/- 27.8 mg/dl in the control subjects (P(v) = 0.015). However, alcohol consumption had no effect on 2-h postprandial glucose levels (difference of 18.5 mg/dl in the control group vs. 17.7 mg/dl in the alcohol group, P(v) = 0.97). Patients in the alcohol group with higher baseline A1C levels had greater reductions in FPG (age-adjusted correlation -0.57, P(v) < 0.001). No significant changes were observed in the levels of bilirubin, alkaline phosphatase, alanine aminotransferase, or aspartate aminotransferase, and no notable adverse effects were reported. Participants in the alcohol group reported an improvement in the ability to fall asleep (P(v) < 0.001).

CONCLUSIONS

Among patients with type 2 diabetes who had previously abstained from alcohol, initiation of moderate daily alcohol consumption reduced FPG but not postprandial glucose. Patients with higher A1C may benefit more from the favorable glycemic effect of alcohol. Further intervention studies are needed to confirm the long-term effect of moderate alcohol intake.

Cholesterol homeostasis in the developing brain: a possible new target for ethanol

Cholesterol is an essential component of cell membranes and plays an important role in signal transduction. This brief overview presents evidence from the literature that ethanol may affect cholesterol homeostasis and that, in the developing brain, this may be involved in its developmental neurotoxicity. The effects caused by inborn errors of cholesterol synthesis and by in utero ethanol exposure present several similarities in humans (eg, Smith-Lemli-Opitz syndrome and fetal alcohol syndrome), as well as in animal models. Ethanol has a cholesterol-reducing effect on the cardiovascular system, and a protective effect against Alzheimer's disease, whose pathogenesis has been linked to altered cholesterol homeostasis in the brain. In vitro, ethanol affects several functions that are mediated by cholesterol and important for brain development, such as glial cell proliferation, synaptogenesis, neuronal survival and neurite outgrowth. The brain contains high levels of cholesterol, mostly synthesized in situ. Astrocytes produce large amounts of cholesterol that can be released by these cells and utilized by neurons to form synapses. Ethanol up-regulates the cholesterol transporter ATP binding cassette A1 and cholesterol efflux from primary astrocyte cultures without affecting cholesterol synthesis.