New insights into the molecular basis of alcohol abstinence and relapse in alcohol-associated liver disease

Abstract

Alcohol use disorder (AUD) remains a significant public health concern, affecting around 5% of adults worldwide. Novel pathways of damage have been described during the last years, providing insight into the mechanism of injury due to alcohol misuse beyond the direct effect of ethanol byproducts on the liver parenchyma and neurobehavioral mechanisms. Thus, the gut-liver-brain axis and immune system involvement could be therapeutic targets for AUD. In particular, a change in gut microbiota composition and function, especially bile acid homeostasis, and these changes can improve after alcohol cessation. Alcohol can also directly disrupt intestinal and blood-brain barriers. Activation of the immune system can be triggered by intestinal barrier dysfunction and translocation of bacteria, pathogen-associated molecular patterns (such as lipopolysaccharide), cytokines, and damage-associated molecular patterns. These factors in turn promote liver and brain inflammation and progression of liver fibrosis. Other involved mechanisms include oxidative stress, apoptosis, autophagy, and the release of extracellular vesicles and miRNA from hepatocytes. Potential therapeutic targets include gut microbiota (probiotics and fecal microbiota transplantation), neuroinflammatory pathways, as well as neuroendocrine pathways, e.g.: the ghrelin system (ghrelin receptor blockade), incretin mimetics (GLP-1 analogs), and the mineralocorticoid receptor system (spironolactone). In addition, support with psychological and behavioral treatments is essential to address the multiple dimensions of AUD. In the future, a personalized approach considering these novel targets can contribute to significantly decreasing the alcohol-related burden of disease.