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Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 28, 2018; 24(32): 3617-3625
Published online Aug 28, 2018. doi: 10.3748/wjg.v24.i32.3617
Helicobacter pylori infection and liver diseases: Epidemiology and insights into pathogenesis
Kazuya Okushin, Takeya Tsutsumi, Kazuhiko Ikeuchi, Akira Kado, Kenichiro Enooku, Hidetaka Fujinaga, Kyoji Moriya, Hiroshi Yotsuyanagi, Kazuhiko Koike
Kazuya Okushin, Akira Kado, Kenichiro Enooku, Hidetaka Fujinaga, Kazuhiko Koike, Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
Kazuya Okushin, Kyoji Moriya, Department of Infection Control and Prevention, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
Takeya Tsutsumi, Kazuhiko Ikeuchi, Hiroshi Yotsuyanagi, Division of Infectious Diseases, Advanced Clinical Research Center, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
Kazuhiko Ikeuchi, Kyoji Moriya, Department of Infectious Diseases, The University of Tokyo, Tokyo 113-8655, Japan
Author contributions: Okushin K and Tsutsumi T contributed to selecting references and drafting the manuscript; Ikeuchi K, Kado A, Enooku K, Fujinaga H, Moriya K, and Yotsuyanagi H participated in the critical revision of the manuscript to ensure that the intellectual content achieved a high standard; Koike K participated in selecting the references, drafting, and critically revising the manuscript to ensure that the intellectual content achieved a high standard; all authors have reviewed and approved the final version of the manuscript.
Conflict-of-interest statement: No author has any relevant conflicts 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: Takeya Tsutsumi, MD, PhD, Associate Professor, Division of Infectious Diseases, Advanced Clinical Research Center, Institute of Medical Science, University of Tokyo, 4-6-1 Shiroganedai, Minato-ku, Tokyo 108-8639, Japan. tsutsumi@ims.u-tokyo.ac.jp
Telephone: +81-3-34438111 Fax: +81-3-54495427
Received: April 26, 2018
Peer-review started: April 26, 2018
First decision: May 24, 2018
Revised: May 30, 2018
Accepted: June 27, 2018
Article in press: June 27, 2018
Published online: August 28, 2018
Abstract

Both Helicobacter pylori (H. pylori) infection and liver diseases, including nonalcoholic fatty liver disease (NAFLD), viral hepatitis, and hepatocellular carcinoma (HCC), have high prevalences worldwide, and the relationship between H. pylori infection and liver disease has been discussed for many years. Although positive correlations between H. pylori and NAFLD have been identified in some clinical and experimental studies, negative correlations have also been obtained in high-quality clinical studies. Associations between H. pylori and the pathogenesis of chronic viral hepatitis, mainly disease progression with fibrosis, have also been suggested in some clinical studies. Concerning HCC, a possible role for H. pylori in hepatocarcinogenesis has been identified since H. pylori genes have frequently been detected in resected HCC specimens. However, no study has revealed the direct involvement of H. pylori in promoting the development of HCC. Although findings regarding the correlations between H. pylori and liver disease pathogenesis have been accumulating, the existing data do not completely lead to an unequivocal conclusion. Further high-quality clinical and experimental analyses are necessary to evaluate the efficacy of H. pylori eradication in ameliorating the histopathological changes observed in each liver disease.

Keywords: Helicobacter pylori, Nonalcoholic fatty liver disease, Nonalcoholic steatohepatitis, Hepatitis C virus, Hepatitis B virus, Viral hepatitis, Hepatocellular carcinoma

Core tip: Both Helicobacter pylori (H. pylori) infection and liver diseases have high prevalences worldwide, and their relationship has been discussed for a long time. In this review, we comprehensively summarize positive and negative correlations suggested in clinical and experimental studies, and conclude that existing data cannot fully lead us to make a decision. We also point out the necessity of further analyses evaluating the efficacy of H. pylori eradication on histopathological changes in each liver disease. We believe this paper would help readers to gain a better understanding of the relationship between H. pylori and liver diseases.