MicroRNA-21 Contributes to Reduced Microvascular Function in Binge Drinking Young Adults

miRNAs in patients with alcoholic liver disease: a systematic review and meta-analysis

INTRODUCTION

Alcoholic liver disease (ALD) encompasses a spectrum of liver conditions, including liver steatosis, alcoholic hepatitis (AH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). microRNAs (miRNAs) have garnered significant interest as potential biomarkers for ALD.

METHODS

We searched PubMed, Embase, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) systemically from inception to June 2024. All extracted data was stratified according to the stages of ALD. The vote-counting strategy performed a meta-analysis on miRNA expression profiles.

RESULTS

We included 40 studies. In serum of individuals with alcohol-use vs. no alcohol-use, miRNA-122 and miRNA-155 were upregulated, and miRNA-146a was downregulated. In patients with ALD vs. healthy controls, miRNA-122 and miRNA-155 were also upregulated, and miRNA-146a was downregulated. However, in patients with AH vs. healthy individuals, only the serum miRNA-122 level was upregulated. Due to insufficient data on diagnostic accuracy, we failed to conclude the ability of miRNAs to distinguish between different stages of ALD-related liver fibrosis. The results for ALD-related HCC were also insufficient and controversial.

CONCLUSIONS

Circulating miRNA-122 was the most promising biomarker to manage individuals with ALD. More studies were needed for the diagnostic accuracy of miRNAs in ALD.

REGISTRATION

This protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (www.crd.york.ac.uk/prospero/) with registration number CRD42023391931.

Adipose tissue homeostasis orchestrates the oxidative, energetic, metabolic and endocrine disruption induced by binge drinking in adolescent rats

Binge drinking (BD) is the most common alcohol consumption model for adolescents, and has recently been related to the generation of high oxidation and insulin resistance (IR). White adipose tissue (WAT) is a target organ for insulin action that regulates whole-body metabolism by secreting adipokines. The present study aimed to analyse the oxidative, inflammatory, energetic and endocrine profile in the WAT of BD-exposed adolescent rats, to obtain an integrative view of insulin secretion and WAT in IR progression. Two groups of male adolescent rats were used: control (n = 8) and BD (n = 8). An intermittent i.p. BD model (20% v/v) was used during 3 consecutive weeks. BD exposure led to a pancreatic oxidative imbalance, which was joint to high insulin secretion by augmenting deacetylase sirtuin-1 (SIRT-1) pancreatic expression and serum adipsin levels. However, BD rats had hyperglycaemia and high homeostasis model assessment of insulin resistance value (HOMA-IR). BD exposure in WAT increased lipid oxidation, as well as decreased insulin receptor substrate 1 (IRS-1) and AKT expression, sterol regulatory element-binding protein 1 (SREBP1), forkhead box O3A (FOXO3a) and peroxisome proliferator-activated receptor γ (PPARγ), and adipocyte size. BD also affected the expression of proteins related to energy balance, such as SIRT-1 and AMP activated protein kinase (AMPK), affecting the adipokine secretion profile (increasing resistin/adiponectin ratio). BD altered the entire serum lipid profile, increasing the concentration of free fatty acids. In conclusion, BD led to an oxidative imbalance and IR process in WAT, which modified the energy balance in this tissue, decreasing the WAT lipogenic/lipolytic ratio, affecting adipokine secretion and the systemic lipid profile, and contributing to the progression of IR. Therefore, WAT is key in the generation of metabolic and endocrine disruption after BD exposure during adolescence in rats. KEY POINTS: Adolescent rat binge drinking (BD) exposure leads to hepatic and systemic oxidative stress (OS) via reactive oxygen species generation, causing hepatic insulin resistance (IR) and altered energy metabolism. In the present study, BD exposure in adolescent rats induces OS in the pancreas, with increased insulin secretion despite hyperglycaemia, indicating a role for IR in white adipose tissue (WAT) homeostasis. In WAT, BD produces IR and an oxidative and energetic imbalance, triggering an intense lipolysis where the serum lipid profile is altered and free fatty acids are increased, consistent with liver lipid accumulation and steatosis. BD exposure heightens inflammation in WAT, elevating pro-inflammatory and reducing anti-inflammatory adipokines, favouring cardiovascular damage. This research provides a comprehensive view of how adolescent BD in rats impacts liver, WAT and pancreas homeostasis, posing a risk for future cardiometabolic complications in adulthood.

DNA Hypomethylation as a Potential Link between Excessive Alcohol Intake and Cardiometabolic Dysfunction in Morbidly Obese Adults

A large percentage of obese patients in the United States suffer a comorbid substance use disorder, mainly alcohol use. Alcohol consumption interferes with the absorption of dietary methyl donors such as folate required for the one-carbon metabolism pathway and subsequently for DNA methylation. In this study, we assessed the association between alcohol consumption and DNA methylation in obese subjects. We obtained visceral adipose tissue (VAT) biopsies from bariatric patients. DNA methylation of 94 genes implicated in inflammation and immunity were analyzed in VAT in relation to alcohol consumption data obtained via questionnaires. Vasoreactivity was measured in the brachial artery and the VAT-isolated arterioles. Pro-inflammatory genes were significantly hypomethylated in the heavy drinking category correlating with higher levels of circulating inflammatory cytokines. Alcohol consumption correlated positively with body mass index (BMI), fat percentage, insulin resistance, impaired lipid profile, and systemic inflammation and negatively with plasma folate and vitamin B12, inflammatory gene DNA methylation, and vasoreactivity. In conclusion, these data suggest that alcohol intake is associated with lower DNA methylation and higher inflammation and cardiometabolic risk in obese individuals.

The effects of alcohol consumption on flow-mediated dilation in humans: A systematic review

Changes in endothelial function may contribute to the positive and negative effects of alcohol consumption on cardiovascular conditions, such as hypertension and coronary artery disease. Numerous studies have used brachial artery flow-mediated dilation (FMD) to examine the effects of alcohol consumption on endothelial function in humans. However, the findings are inconsistent and may be due to multiple factors such as heterogeneity in subject characteristics, the alcohol use pattern, and amount/dose of alcohol consumed. Therefore, the aim of this systematic review was to investigate the effect of alcohol consumption on brachial artery FMD in humans considering the above-mentioned factors. This review found that while light to moderate alcohol consumption may have minimal effects on FMD, heavy alcohol consumption was associated with a decrease in FMD. However, most of the published studies included healthy, younger, and male individuals, limiting generalizability to other populations. Future studies should include more women, older subjects, and those from diverse and underrepresented backgrounds.

The effects of repeated binge drinking on arterial stiffness and urinary norepinephrine levels in young adults

OBJECTIVES

The aim of this study was to investigate the effect of repeated binge drinking and moderate alcohol consumption in young adults on arterial stiffness and sympathetic activity.

METHODS

We enrolled 49 healthy young adults, free of cardiovascular diseases (25 men; age: 23.5 ± 0.4 years; BMI: 23.4 ± 0.4 kg/m; mean ± S.E). Individuals included were those with a history of repeated binge drinking (>2 years duration; n = 20), drank at moderate levels (MODs, >5 years duration; n = 16) and abstained from alcohol (last 2-3 years; n = 13). Arterial stiffness was assessed using carotid to femoral pulse wave velocity (cfPWV) and sympathetic activity was assessed using 24-h urinary norepinephrine levels. Also measured was aortic SBP and augmentation index (AIx), a measure of wave reflection.

RESULTS

Binge drinkers and MODs had higher cfPWV than alcohol abstainers (0.6 and 0.5 m/s, respectively; P ≤ 0.04). In addition, binge drinkers had higher urinary norepinephrine levels than MODs and alcohol abstainers (P < 0.05). Higher cfPWV were correlated with higher norepinephrine levels (r = 0.35. P = 0.02). Aortic SBP (P = 0.2) and AIx (P = 0.96) were similar among binge drinkers, MODs and alcohol abstainers.

CONCLUSION

Our findings suggest that repeated exposure to alcohol, regardless of drinking pattern, may increase aortic arterial stiffness in healthy young adults. In addition, sympathetic activation, reflected by increased 24-h urinary norepinephrine levels, may contribute to alcohol-induced arterial stiffening in young adults.

MicroRNA-21-Enriched Exosomes as Epigenetic Regulators in Melanomagenesis and Melanoma Progression: The Impact of Western Lifestyle Factors

DNA mutation-induced activation of RAS-BRAF-MEK-ERK signaling associated with intermittent or chronic ultraviolet (UV) irradiation cannot exclusively explain the excessive increase of malignant melanoma (MM) incidence since the 1950s. Malignant conversion of a melanocyte to an MM cell and metastatic MM is associated with a steady increase in microRNA-21 (miR-21). At the epigenetic level, miR-21 inhibits key tumor suppressors of the RAS-BRAF signaling pathway enhancing proliferation and MM progression. Increased MM cell levels of miR-21 either result from endogenous upregulation of melanocytic miR-21 expression or by uptake of miR-21-enriched exogenous exosomes. Based on epidemiological data and translational evidence, this review provides deeper insights into environmentally and metabolically induced exosomal miR-21 trafficking beyond UV-irradiation in melanomagenesis and MM progression. Sources of miR-21-enriched exosomes include UV-irradiated keratinocytes, adipocyte-derived exosomes in obesity, airway epithelium-derived exosomes generated by smoking and pollution, diet-related exosomes and inflammation-induced exosomes, which may synergistically increase the exosomal miR-21 burden of the melanocyte, the transformed MM cell and its tumor environment. Several therapeutic agents that suppress MM cell growth and proliferation attenuate miR-21 expression. These include miR-21 antagonists, metformin, kinase inhibitors, beta-blockers, vitamin D, and plant-derived bioactive compounds, which may represent new options for the prevention and treatment of MM.

Hyperhomocysteinemia and Low Folate and Vitamin B12 Are Associated with Vascular Dysfunction and Impaired Nitric Oxide Sensitivity in Morbidly Obese Patients

There is a high prevalence of hyperhomocysteinemia that has been linked to high cardiovascular risk in obese individuals and could be attributed to poor nutritional status of folate and vitamin B12. We sought to examine the association between blood homocysteine (Hcy) folate, and vitamin B12 levels and vascular dysfunction in morbidly obese adults using novel ex vivo flow-induced dilation (FID) measurements of isolated adipose tissue arterioles. Brachial artery flow-mediated dilation (FMD) was also measured. Subcutaneous and visceral adipose tissue biopsies were obtained from morbidly obese individuals and non-obese controls. Resistance arterioles were isolated in which FID, acetylcholine-induced dilation (AChID), and nitric oxide (NO) production were measured in the absence or presence of the NO synthase inhibitor, L-NAME, Hcy, or the superoxide dismutase mimetic, TEMPOL. Our results demonstrated that plasma Hcy concentrations were significantly higher, while folate, vitamin B12, and NO were significantly lower in obese subjects compared to controls. Hcy concentrations correlated positively with BMI, fat %, and insulin levels but not with folate or vitamin B12. Brachial and arteriolar vasodilation were lower in obese subjects, positively correlated with folate and vitamin B12, and inversely correlated with Hcy. Arteriolar NO measurements and sensitivity to L-NAME were lower in obese subjects compared to controls. Finally, Hcy incubation reduced arteriolar FID and NO sensitivity, an effect that was abolished by TEMPOL. In conclusion, these data suggest that high concentrations of plasma Hcy and low concentrations of folate and vitamin B12 could be independent predictors of vascular dysfunction in morbidly obese individuals.

Tetrahydrobiopterin Restores Microvascular Dysfunction in Young Adult Binge Drinkers

BACKGROUND

Repeated binge drinking is associated with reduced microvascular function. However, microvascular responses to pathophysiological stimulus such as high pressure as well as potential mechanisms that underlie binge-induced microvascular dysfunction are unknown. Therefore, using an ex vivo experimental model, we examined microvascular responses following a brief period of high intraluminal pressure in isolated arterioles from young adults who have a history of repeated binge drinking. In addition, we examined whether the application of the endothelial nitric oxide synthase cofactor, tetrahydrobiopterin, would restore microvascular function in response to flow and high intraluminal pressure in young adult binge drinkers.

METHODS

Isolated subcutaneous adipose arterioles were obtained from young adult binge drinkers (BD; n = 14), moderate drinkers (MODs; n = 10), and alcohol abstainers (ABs; n = 12; mean age: 23.7 ± 0.5 years; and body mass index: 23.4 ± 0.4 kg/m2 ). Arteriolar flow-induced dilation (FID, pressure gradient: ∆10 to 100 cm H2 O) was measured before and after acute high intraluminal pressure with and without tetrahydrobiopterin.

RESULTS

Before high pressure, FID at Δ60 and Δ100 cm H2 O pressure gradient in BDs was 14% lower and 18% lower, respectively, than ABs (p < 0.05), while MODs and ABs had similar FID across all pressure gradients (p ≥ 0.2). After high pressure, FID in BDs was further reduced by 10% (p < 0.0005) and this impairment was ameliorated by the treatment of tetrahydrobiopterin (4 to 26% higher, p < 0.005). In contrast, FID after high pressure did not change in MODs and ABs (p ≥ 0.5).

CONCLUSIONS

Microvascular dysfunction in young adult binge drinkers may be exacerbated with acute pathophysiological stimulus. These binge-induced dysfunctions may be reversed by tetrahydrobiopterin, which suggests a role of oxidative stress and/or uncoupled endothelial nitric oxide synthase in binge drinking.