Editorial
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Feb 14, 2015; 21(6): 1691-1702
Published online Feb 14, 2015. doi: 10.3748/wjg.v21.i6.1691
Gut microbiota and liver diseases
Masami Minemura, Yukihiro Shimizu
Masami Minemura, the Third Department of Internal Medicine, Faculty of Medicine, University of Toyama, Toyama 930-0194, Japan
Yukihiro Shimizu, Gastroenterology Center, Nanto Municipal Hospital, Toyama 932-0211, Japan
Author contributions: Minemura M wrote the second half of the manuscript; Shimizu Y organized the whole manuscript and wrote the first half of the manuscript.
Conflict-of-interest: The authors have no conflict-of-interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Yukihiro Shimizu, MD, PhD, Gastroenterology Center, Nanto Municipal Hospital, 936 Inami, Nanto, Toyama 932-0211, Japan. rsf14240@nifty.com
Telephone: +81-763-821475
Received: November 25, 2014
Peer-review started: November 26, 2014
First decision: December 26, 2014
Revised: January 8, 2015
Accepted: January 21, 2015
Article in press: January 21, 2015
Published online: February 14, 2015
Processing time: 77 Days and 21.3 Hours
Abstract

Several studies revealed that gut microbiota are associated with various human diseases, e.g., metabolic diseases, allergies, gastroenterological diseases, and liver diseases. The liver can be greatly affected by changes in gut microbiota due to the entry of gut bacteria or their metabolites into the liver through the portal vein, and the liver-gut axis is important to understand the pathophysiology of several liver diseases, especially non-alcoholic fatty liver disease and hepatic encephalopathy. Moreover, gut microbiota play a significant role in the development of alcoholic liver disease and hepatocarcinogenesis. Based on these previous findings, trials using probiotics have been performed for the prevention or treatment of liver diseases. In this review, we summarize the current understanding of the changes in gut microbiota associated with various liver diseases, and we describe the therapeutic trials of probiotics for those diseases.

Keywords: Gut microbiota; Immune system; Liver disease; Metabolites; Non-alcoholic fatty liver disease; Hepatic encephalopathy

Core tip: Gut microbiota are associated with various human diseases (e.g., metabolic, gastroenterological and liver diseases, and allergies). Genomic analyses of gut microbiota have enabled the comprehensive identification of the population of gut bacteria and revealed that changes in these populations are involved in various diseases’ pathophysiology. The liver is affected by changes in the intestinal milieu due to the entry of gut bacteria or their metabolites into the liver through the portal vein. Here we summarize the current understanding of changes in gut microbiota associated with various liver diseases. We also summarize the recent therapeutic trials of probiotics in liver diseases.