Review
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Sep 7, 2021; 27(33): 5488-5501
Published online Sep 7, 2021. doi: 10.3748/wjg.v27.i33.5488
Microbiota and viral hepatitis: State of the art of a complex matter
Ivana Milosevic, Edda Russo, Ankica Vujovic, Aleksandra Barac, Olja Stevanovic, Stefano Gitto, Amedeo Amedei
Ivana Milosevic, Ankica Vujovic, Aleksandra Barac, Olja Stevanovic, Clinic for Infectious and Tropical Diseases, Clinical Centre of Serbia Faculty of Medicine, University of Belgrade, Belgrade 101801, Serbia
Edda Russo, Stefano Gitto, Amedeo Amedei, Department of Experimental and Clinical Medicine, University of Florence, Firenze 50100, Italy
Author contributions: Russo E and Milosevic I contributed equally; Russo E, Milosevic I and Amedei A conceptualized the review; Milosevic I, Barak A, Vujovic A and Russo E wrote the paper; Milosevic I, Barak A, Vujovic A, Stevanovic O, and Russo E collected the data; Milosevic A, Barak A and Vujovic A, prepared the figures; Gitto S and Amedei A corrected the final version; Barak A, Russo E, and Amedei A acquired the funding; All authors critically revised the manuscript.
Supported by The Italian Ministry of University and Research (MIUR), the Foundation ‘Ente Cassa di Risparmio di Firenze’, No. FCR 2017.
Conflict-of-interest statement: Authors declare no any conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Ivana Milosevic, MD, Associate Professor, Clinic for Infectious and Tropical Diseases, Clinical Centre of Serbia Faculty of Medicine, University of Belgrade, Bul. Oslobodjenja 16, Belgrade 101801, Serbia. ivana.milosevic@med.bg.ac.rs
Received: February 2, 2021
Peer-review started: February 2, 2021
First decision: March 14, 2021
Revised: March 26, 2021
Accepted: July 21, 2021
Article in press: July 21, 2021
Published online: September 7, 2021
Processing time: 212 Days and 13.6 Hours
Abstract

Changes in gut microbiota influence both the gut and liver, which are strictly connected by the so-called “gut–liver axis”. The gut microbiota acts as a major determinant of this relationship in the onset and clinical course of liver diseases. According to the results of several studies, gut dysbiosis is linked to viral hepatitis, mainly hepatitis C virus and hepatitis B virus infection. Gut bacteria-derived metabolites and cellular components are key molecules that affect liver function and modulate the pathology of viral hepatitis. Recent studies showed that the gut microbiota produces various molecules, such as peptidoglycans, lipopolysaccharides, DNA, lipoteichoic acid, indole-derivatives, bile acids, and trimethylamine, which are translocated to the liver and interact with liver immune cells causing pathological effects. Therefore, the existence of crosstalk between the gut microbiota and the liver and its implications on host health and pathologic status are essential factors impacting the etiology and therapeutic approach. Concrete mechanisms behind the pathogenic role of gut-derived components on the pathogenesis of viral hepatitis remain unclear and not understood. In this review, we discuss the current findings of research on the bidirectional relationship of the components of gut microbiota and the progression of liver diseases and viral hepatitis and vice versa. Moreover, this paper highlights the current therapeutic and preventive strategies, such as fecal transplantation, used to restore the gut microbiota composition and so improve host health.

Keywords: Gut microbiota; Hepatitis B virus; Hepatitis C virus; Liver diseases, Fecal transplantation

Core Tip: Changes within the gut microbiota have an impact on the mutual crosstalk between intestinal microbiota and the liver. Gut dysbiosis is linked to viral hepatitis, mainly hepatitis C virus and hepatitis B virus infection. However, concrete mechanisms behind the pathogenic role of gut-derived components on the pathogenesis of viral hepatitis remain unclear. We discuss recent studies to understand the role of gut microbiota.