Impact of chronic low to moderate alcohol consumption on blood lipid and heart energy profile in acetaldehyde dehydrogenase 2-deficient mice

Alcohol Consumption and Cardiovascular Disease: A Narrative Review of Evolving Perspectives and Long-Term Implications

Cardiovascular illnesses remain the primary cause of death, accounting for at least 17.9 million fatalities per year and posing a significant public health problem because of its extensive predominance and effect on healthcare systems. The etiology of cardiovascular disease is complex and involves several environmental and lifestyle factors. Alcohol use is a highly important determinant because of its dual-edged effect on cardiovascular health. Multiple studies indicate that moderate alcohol consumption may have certain advantages, such as slight enhancements in lipid profiles. Conversely, excessive alcohol intake is associated with serious negative consequences, including cardiomyopathy, hypertension, arrhythmias, and even mortality. The aim of this study is to provide a comprehensive analysis of the several effects of alcohol on cardiovascular health and their understanding within the medical field over time. It uses an interpretative narrative review methodology and analyzes studies that focus on genetic risk factors, gender differences, and shifts in paradigms in recent years. This article highlights the need for obtaining a thorough understanding of the effects of alcohol on cardiovascular health to support public health guidelines and clinical practice, and it underscores the significance of including alcohol consumption into the broader context of cardiovascular risk management and identifies important subjects for further study.

A Common East Asian aldehyde dehydrogenase 2*2 variant promotes ventricular arrhythmia with chronic light-to-moderate alcohol use in mice

Chronic heavy alcohol use is associated with lethal arrhythmias. Whether common East Asian-specific aldehyde dehydrogenase deficiency (ALDH2*2) contributes to arrhythmogenesis caused by low level alcohol use remains unclear. Here we show 59 habitual alcohol users carrying ALDH2 rs671 have longer QT interval (corrected) and higher ventricular tachyarrhythmia events compared with 137 ALDH2 wild-type (Wt) habitual alcohol users and 57 alcohol non-users. Notably, we observe QT prolongation and a higher risk of premature ventricular contractions among human ALDH2 variants showing habitual light-to-moderate alcohol consumption. We recapitulate a human electrophysiological QT prolongation phenotype using a mouse ALDH2*2 knock-in (KI) model treated with 4% ethanol, which shows markedly reduced total amount of connexin43 albeit increased lateralization accompanied by markedly downregulated sarcolemmal Nav1.5, Kv1.4 and Kv4.2 expressions compared to EtOH-treated Wt mice. Whole-cell patch-clamps reveal a more pronounced action potential prolongation in EtOH-treated ALDH2*2 KI mice. By programmed electrical stimulation, rotors are only provokable in EtOH-treated ALDH2*2 KI mice along with higher number and duration of ventricular arrhythmia episodes. The present research helps formulate safe alcohol drinking guideline for ALDH2 deficient population and develop novel protective agents for these subjects.

Mediterranean Alcohol-Drinking Patterns and All-Cause Mortality in Women More Than 55 Years Old and Men More Than 50 Years Old in the "Seguimiento Universidad de Navarra" (SUN) Cohort

BACKGROUND

Most of the available epidemiological evidence on alcohol and chronic disease agrees on recommending alcohol abstention to young people, but some controversy exists about the most appropriate recommendation for alcohol abstention for people of older ages. A growing body of evidence suggests that the pattern of alcohol consumption is likely to be a strong effect modifier. The Mediterranean Alcohol Drinking Pattern (MADP) represents a score integrating several dimensions of drinking patterns (moderation, preference for red wine, drinking with meals, and avoiding binge drinking). Our aim was to clarify this issue and provide more precise recommendations on alcohol consumption.

METHODS

We prospectively followed-up 2226 participants (men older than 50 years and women older than 55 years at baseline) in the Seguimiento Universidad de Navarra (SUN) cohort. We classified participants into three categories of adherence to the MADP score (low, moderate, and high), and we added a fourth category for abstainers. Cox regression models estimated multivariable-adjusted hazard ratios (HR) of all-cause death and 95% confidence intervals (CI) using low MADP adherence as the reference category.

RESULTS

The strongest reduction in risk of mortality was observed for those with high adherence to the MADP, with an HR of 0.54 (95% CI: 0.37-0.80). The moderate adherence group (HR = 0.65, 95% CI: 0.44-0.96) and the abstention group (HR = 0.60, 95% CI: 0.36-0.98) also exhibited lower risks of mortality than the low MADP adherence group.

CONCLUSIONS

based on the available evidence, a public health message can be provided to people older than 50 years as follows: among those who drink alcohol, high adherence to the MADP score could substantially reduce their risk of all-cause mortality.

Alcohol, Drinking Pattern, and Chronic Disease

This review discusses the inconsistent recommendations on alcohol consumption and its association with chronic disease, highlighting the need for an evidence-based consensus. Alcohol is an addictive substance consumed worldwide, especially in European countries. Recommendations on alcohol consumption are controversial. On one hand, many nonrandomized studies defend that moderate consumption has a beneficial cardiovascular effect or a lower risk of all-cause mortality. On the other hand, alcohol is associated with an increased risk of cancer, neurological diseases, or injuries, among others. For years, efforts have been made to answer the question regarding the safe amount of alcohol intake, but controversies remain. Observational studies advocate moderate alcohol consumption following a Mediterranean pattern (red wine with meals avoiding binge drinking) as the best option for current drinkers. However, agencies such as the IARC recommend abstention from alcohol as it is a potent carcinogen. In this context, more randomized trial with larger sample size and hard clinical endpoints should be conducted to clarify the available evidence and provide clinicians with support for their clinical practice.

Impact and potential mechanism of effects of chronic moderate alcohol consumption on cardiac function in aldehyde dehydrogenase 2 gene heterozygous mice

Background

Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a key enzyme in alcohol metabolism. The ALDH2*2 mutations are found in approximately 45% of East Asians, with 40% being heterozygous (HE) ALDH2*1/*2 and 5% homozygous (HO) ALDH2*2/*2. Studies have shown that HO mice lack cardioprotective effects induced by moderate alcohol consumption. However, the impact of moderate alcohol consumption on cardiac function in HE mice is unknown.

Methods

In this study, HO, HE, and wild‐type (WT) mice were subjected to a 6‐week moderate alcohol drinking protocol, following which myocardial tissue and cardiomyocytes of the mice were extracted.

Results

We found that moderate alcohol exposure did not increase mortality, myocardial fibrosis, apoptosis, or inflammation in HE mice, which differs from the effects observed in HO mice. After exposure to the 6‐week alcohol drinking protocol, there was impaired cardiac function, cardiomyocyte contractility, and intracellular Ca²⁺ homeostasis and mitochondrial function in both HE and HO mice as compared to WT mice. Moreover, these animals showed overt oxidative stress production and increased levels of the activated forms of calmodulin‐dependent protein kinase II (CaMKII) and ryanodine receptor type 2 (RYR2) phosphorylation protein.

Conclusion

We found that moderate alcohol exposure impaired cardiac function in HE mice, possibly by increasing reactive oxygen species (ROS)/CaMKII/RYR2‐mediated Ca²⁺ handling abnormalities. Hence, we advocate that people with ALDH2*1/*2 genotypes rigorously avoid alcohol consumption to prevent potential cardiovascular harm induced by moderate alcohol consumption.

Effects of chronic moderate alcohol consumption on right ventricle and pulmonary remodelling

NEW FINDINGS

What is the central question of this study? Does the consumption of a moderate amount of alcohol differentially impact the heart ventricles and pulmonary vasculature. What is the main finding and its importance? Moderate alcohol consumption for a short period of time impaired pulmonary vascular cellular renewal through an apoptosis resistance pattern that ultimately affected the right ventricular function and structure. These findings support the need for a deeper understanding of effects of moderate alcohol consumption on the overall cardiovascular and pulmonary systems.

ABSTRACT

Over the past decades, observational studies have supported an association between moderate alcohol consumption and a lower risk of cardiovascular disease and mortality. However, recent and more robust meta-analyses have raised concerns around the robustness of the evidence for the cardioprotective effects of alcohol. Also, studies of the functional, structural and molecular changes promoted by alcohol have focused primarily on the left ventricle, ignoring the fact that the right ventricle could adapt differently. The aim of this study was to evaluate the bi-ventricular impact of daily moderate alcohol intake, during a 4-week period, in a rodent model. Male Wistar rats were allowed to drink water (Control) or a 5.2% ethanol mixture (ETOH) for 4 weeks. At the end of the protocol bi-ventricular haemodynamic recordings were performed and samples collected for further histological and molecular analysis. ETOH ingestion did not impact cardiac function. However, it caused right ventricle hypertrophy, paralleled by an activation of molecular pathways responsible for cell growth (ERK1/2, AKT), proteolysis (MURF-1) and oxidative stress (NOX4, SOD2). Furthermore, ETOH animals also presented remodelling of the pulmonary vasculature with an increase in pulmonary arteries' medial thickness, which was characterized by increased expression of apoptosis-related proteins expression (BCL-XL, BAX and caspases). Moderate alcohol consumption for a short period of time impaired the lungs and the right ventricle early, before any change could be detected on the left ventricle. Right ventricular changes might be secondary to alcohol-induced pulmonary vasculature remodelling.

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

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

Engineered Animal Models Designed for Investigating Ethanol Metabolism, Toxicity and Cancer

Excessive consumption of alcohol is a leading cause of lifestyle-induced morbidity and mortality worldwide. Although long-term alcohol abuse has been shown to be detrimental to the liver, brain and many other organs, our understanding of the exact molecular mechanisms by which this occurs is still limited. In tissues, ethanol is metabolized to acetaldehyde (mainly by alcohol dehydrogenase and cytochrome p450 2E1) and subsequently to acetic acid by aldehyde dehydrogenases. Intracellular generation of free radicals and depletion of the antioxidant glutathione (GSH) are believed to be key steps involved in the cellular pathogenic events caused by ethanol. With continued excessive alcohol consumption, further tissue damage can result from the production of cellular protein and DNA adducts caused by accumulating ethanol-derived aldehydes. Much of our understanding about the pathophysiological consequences of ethanol metabolism comes from genetically-engineered mouse models of ethanol-induced tissue injury. In this review, we provide an update on the current understanding of important mouse models in which ethanol-metabolizing and GSH-synthesizing enzymes have been manipulated to investigate alcohol-induced disease.

ALDH2 deficiency inhibits Ox-LDL induced foam cell formation via suppressing CD36 expression

Foam cell formation plays an important role in the initiation and progression of atherosclerosis. Aldehyde dehydrogenase 2 (ALDH2), a key enzyme for aldehyde metabolism, is associated with coronary artery disease and affects atherosclerotic plaque vulnerability. However, the role of ALDH2 in foam cell formation remains unclear. Using peritoneal macrophages from ALDH2-deficient and control mice, we found that ALDH2 deficiency suppressed foam cell formation induced by oxidized low-density lipoproteins (ox-LDL) but not acetylated low-density lipoproteins (ac-LDL) ex vivo. After incubation with ox-LDL, ALDH2-deficient macrophages expressed lower levels of CD36 but the expression of other lipid metabolism-related proteins including SRA, LOX-1, ABCA-1, ABCG-1 and ACAT-1 was not changed in ALDH2^-/- macrophages. Using CD36 inhibitor, we confirmed that CD36 contributes to the effect of ALDH2 on foam cell formation. PPARγ was downregulated in ox-LDL treated ALDH2^-/- macrophages. 4-HNE was increased by ALDH2 deficiency and high concentration of 4-HNE suppressed the expression of PPARγ. These data suggest that ALDH2 plays an important role in foam cell formation via 4-HNE/PPARγ/CD36 pathway.

Aqueous Extract of Pepino (Solanum muriactum Ait) Leaves Ameliorate Lipid Accumulation and Oxidative Stress in Alcoholic Fatty Liver Disease

Chronic alcohol intake leads to alcoholic fatty liver. The pathogenesis of alcoholic fatty liver is related to abnormal lipid accumulation, oxidative stress, endotoxins, and cytokines. Solanum muricatum Ait. (Pepino) is a plant food commonly cultivated in the Penghu island, Taiwan. Previous studies indicated that the aqueous extract of pepino was able to attenuate diabetic progression via its antioxidative and anti-inflammatory effects. However, the mechanisms of the antioxidative and anti-inflammatory effects of pepino leaf in preventing alcoholic fatty liver remain unknown. In this study, Lieber–DeCarli ethanol-containing liquid diet was used to induce alcoholic hepatic injury in C57BL/6 mice. The hepatoprotective effects and the related mechanisms of aqueous extract of pepino leaf (AEPL) were examined. Our results showed that 2% AEPL treatments protected the liver from ethanol-induced injury through reducing serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC) and triglyceride (TG) (all p < 0.05). AEPL had the effects in improving the ethanol-induced lipid accumulation in mice under histological examination. Molecular data indicated that the anti-lipid accumulation effect of AEPL might be mediated via inducing hepatic levels of phospho-adenosine monophosphate-activated kinase (p-AMPK) and peroxisome proliferator-activated receptor (PPAR)-α, and reducing the expressions of hepatic lipogenic enzymes, including sterol regulatory element-binding protein (SREBP)-1c, acetyl-CoA carboxylase (ACC), and fatty acid synthase (FAS) (all p < 0.05). AEPL also decreased hepatic levels of thiobarbituric acid relative substances (TBARS), tumor necrosis factor (TNF)-α, and interleukin (IL)-6, as well as the expression of nuclear factor kappa B (NF-κB) (all p < 0.05). Moreover, AEPL significantly elevated the activities of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx), and glutathione (GSH) content compared to the ethanol-fed group (all p < 0.05). Our present study suggests that AEPL could protect the liver against ethanol-induced oxidative injury and lipid accumulation.

Effects of smoking and alcohol consumption on lipid profile in male adults in northwest rural China

OBJECTIVES

To determine the individual and combined influences of smoking and alcohol consumption on lipid profile in male adults in northwest rural China.

DESIGN

Cross-sectional study.

METHODS

In total, 4614 subjects were enrolled in the cross-sectional study, performed between 2008 and 2012. The present study examined males aged ≥18 years from northwest rural China (n = 707). Data on current smoking and drinking status were collected. Logistic regression was used to estimate the individual and combined influences of smoking and alcohol consumption on lipid profile. Age, ethnic group, educational background, smoking (or alcohol consumption), waist circumference, body mass index, blood pressure and fasting blood glucose were adjusted as confounders.

RESULTS

Total cholesterol (TC)/high-density lipoprotein cholesterol (HDL-C) ratio, triglycerides (TG)/HDL-C ratio, low-density lipoprotein cholesterol (LDL-C)/HDL-C ratio and visceral adiposity index (VAI) were significantly higher in smokers than in non-smokers, whereas HDL-C was lower in smokers. TG/HDL-C ratio, LDL-C/HDL-C ratio, TG, lipid accumulation product and VAI were significantly higher in drinkers than non-drinkers. After adjustment for confounders, significant relationships were observed between smoking status and any dyslipidemia, low HDL-C and high VAI (odds ratios [ORs]: 2.53 [95% confidence interval {CI}: 1.25-5.15], 6.13 [95% CI: 2.84-13.25] and 4.39 [95% CI: 2.02-9.54], respectively). The OR for any dyslipidaemia was 1.94 (95% CI: 1.09-3.48) for subjects who smoke and drank alcohol compared with subjects who did not smoke or drink alcohol.

CONCLUSIONS

Abnormalities in lipid profile are correlated with smoking and alcohol consumption, which calls for intervention strategies to prevent dyslipidaemia and control risk factors for cardiovascular disease.

Moderate alcohol intake induces thermogenic brown/beige adipocyte formation via elevating retinoic acid signaling

Clinically, low and moderate alcohol intake improves human health with protection against metabolic syndromes, including type 2 diabetes; however, mechanisms that are associated with these effects remain to be elucidated. The aims of this study were to investigate the effects of moderate alcohol intake on thermogenic brown/beige adipocyte formation and glucose and lipid homeostasis, as well as the involvement of retinoic acid (RA) signaling in the entire process. C57BL6 male mice were supplemented with 8% (w/v) alcohol in water for 1 or 4 mo. Alcohol intake prevented body weight gain, induced the formation of uncoupling protein 1-positive beige adipocytes in white adipose tissue, and increased thermogenesis in mice, which is associated with decreased serum glucose and triacylglycerol levels. Mechanistically, alcohol intake increased RA levels in serum and adipose tissue, which was associated with increased expression of aldehyde dehydrogenase family 1 subfamily A1 (Aldh1a1). When RA receptor-α signaling was conditionally blocked in platelet-derived growth factor receptor-α-positive adipose progenitors, the effects of alcohol on beige adipogenesis were largely abolished. Finally, moderate alcohol prevented high-fat diet-induced obesity and metabolic dysfunction. In conclusion, moderate alcohol intake induces thermogenic brown/beige adipocyte formation and promotes glucose and lipid oxidation via elevation of RA signaling.-Wang, B., Wang, Z., de Avila, J. M., Zhu, M.-J., Zhang, F., Gomez, N. A., Zhao, L., Tian, Q., Zhao, J., Maricelli, J., Zhang, H., Rodgers, B. D., Du, M. Moderate alcohol intake induces thermogenic brown/beige adipocyte formation via elevating retinoic acid signaling.

Environmental influences in the etiology of colorectal cancer: the premise of metabolomics

PURPOSE OF REVIEW

In this review we discuss how environmental exposures predominate the etiology of colorectal cancer (CRC). With CRC being a personalized disease influenced by genes and environment, our goal was to explore the role metabolomics can play in identifying exposures, assessing the interplay between co-exposures, and the development of personalized therapeutic interventions.

RECENT FINDINGS

Approximately 10 % of CRC cases can be explained by germ-line mutations, whereas the prevailing majority are caused by an initiating exposure event occurring decades prior to diagnosis. Recent research has shown that dietary metabolites are linked to a procarcinogenic or protective environment in the colon which is modulated by the microbiome. In addition, excessive alcohol has been shown to increase the risk of CRC and is dependent on diet (folate), the response of microbiome, and genetic polymorphisms within the folate and alcohol metabolic pathways. Metabolomics can not only be used to identify this modulation of host metabolism, which could affect the progression of the tumors but also response to targeted therapeutics.

SUMMARY

This review highlights the current understanding of the multifaceted etiology and mechanisms of CRC development but also highlights where the field of metabolomics can contribute to a greater understanding of environmental exposure in CRC.