Background Chronic alcohol abuse is associated with intestinal bacterial overgrowth, increased intestinal permeability, and translocation of microbial products from the intestine to the portal circulation and liver. Translocated microbial products contribute to experimental alcoholic liver disease. Aim To investigate the physiological relevance of the intestinal microbiota in alcohol-induced liver injury. Methods We subjected germ-free and conventional C57BL/6 mice to a model of acute alcohol exposure that mimics binge drinking. Results Germ-free mice showed significantly greater liver injury and inflammation after oral gavage of ethanol compared with conventional mice. In parallel, germ-free mice exhibited increased hepatic steatosis and upregulated expression of genes involved in fatty acid and triglyceride synthesis compared with conventional mice after acute ethanol administration. The absence of microbiota was also associated with increased hepatic expression of ethanol metabolizing enzymes, which led to faster ethanol elimination from the blood and lower plasma ethanol concentrations. Intestinal levels of ethanol metabolizing genes showed regional expression differences, and were overall higher in germ-free relative to conventional mice. Conclusion Our findings indicate that absence of the intestinal microbiota increases hepatic ethanol metabolism and the susceptibility to binge-like alcohol drinking.

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