Copyright ©2012 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Hepatol. Apr 27, 2012; 4(4): 110-118
Published online Apr 27, 2012. doi: 10.4254/wjh.v4.i4.110
Bacterial translocation and changes in the intestinal microbiome associated with alcoholic liver disease
Arthur W Yan, Bernd Schnabl
Arthur W Yan, Division of Gastroenterology, Department of Medicine, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, United States
Bernd Schnabl, Department of Medicine, University of California San Diego, La Jolla, CA 92093, United States
Author contributions: Yan AW and Schnabl B contributed equally to this work and wrote the paper.
Supported by NIH grants No. K08 DK081830 and No. R01 AA020703; the Pilot Project Program of the Southern California Research Center for ALPD and Cirrhosis No. P50AA11999 funded by the National Institute on Alcohol Abuse and Alcoholism; and ABMRF/The Foundation for Alcohol Research to Schnabl B.
Correspondence to: Bernd Schnabl, MD, Department of Medicine, University of California San Diego, MC0702, 9500 Gilman Drive, La Jolla, CA 92093, United States. beschnabl@ucsd.edu
Telephone: +1-858-8225339 Fax: +1-858-8225370
Received: August 3, 2011
Revised: November 13, 2011
Accepted: April 24, 2012
Published online: April 27, 2012

Alcoholic liver disease progresses through several stages of tissue damage, from simple steatosis to alcoholic hepatitis, fibrosis, or cirrhosis. Alcohol also affects the intestine, increases intestinal permeability and changes the bacterial microflora. Liver disease severity correlates with levels of systemic bacterial products in patients, and experimental alcoholic liver disease is dependent on gut derived bacterial products in mice. Supporting evidence for the importance of bacterial translocation comes from animal studies demonstrating that intestinal decontamination is associated with decreased liver fibrogenesis. In addition, mice with a gene mutation or deletion encoding receptors for either bacterial products or signaling molecules downstream from these receptors, are resistant to alcohol-induced liver disease. Despite this strong association, the exact molecular mechanism of bacterial translocation and of how changes in the intestinal microbiome contribute to liver disease progression remains largely unknown. In this review we will summarize evidence for bacterial translocation and enteric microbial changes in response to alcoholic liver injury and chronic alcoholic liver disease. We will further describe consequences of intestinal dysbiosis on host biology. We finally discuss how therapeutic interventions may modify the gastrointestinal microflora and prevent or reduce alcoholic liver disease progression.

Keywords: Alcoholic liver disease, Microbiome, Dysbiosis, Bacterial translocation, Steatohepatitis