Gut Microbiota and Ageing: A Critical Crosstalk in Alcohol-Related Liver Disease

Alcohol-related liver disease (ALD) poses a significant global health burden, driven by complex mechanisms including oxidative stress, inflammation, and gut-liver axis disruption. While the individual roles of gut microbiota dysbiosis and ageing in ALD pathogenesis are increasingly recognized, their synergistic interaction remains poorly understood. This review synthesizes current evidence to argue that there is an interaction between ageing and the gut microbiota that collectively amplifies progression of ALD. Specifically, ageing promotes gut dysbiosis through immunosenescence (e.g., reduced IgA diversification and antimicrobial peptide decline), intestinal barrier failure, and altered microbial metabolite profiles (e.g., decreased short-chain fatty acids and dysregulated bile acid metabolism). Conversely, dysbiosis-derived metabolites and endotoxins modulate ageing-related signaling pathways, including SIRT1, FOXO, and Nrf2, thereby accelerating hepatic cellular senescence, inflammation, and fibrogenesis. Furthermore, we also discussed the typical microbial changes in ALD. These include an increase in the Proteobacteria, a decrease in the Bacteroidetes, as well as imbalances in fungi and viruses. In ageing, similar but distinct shifts occur, such as reduced microbial diversity, decreased short-chain fatty acid producers, and increased intestinal permeability. Therapeutic strategies targeting the gut microbiota (probiotics, fecal microbiota transplantation) or ageing-related pathways (SIRT1 activators) hold promise. Future research priorities include validating ageing-associated microbial signatures as predictors of ALD progression and testing microbiota-targeted interventions in aged preclinical models. Collectively, this review identifies the microbiota-ageing axis as a tractable therapeutic target for ALD and provides a framework for future mechanistic and translational studies.