Copyright ©The Author(s) 2018. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 7, 2018; 24(37): 4217-4223
Published online Oct 7, 2018. doi: 10.3748/wjg.v24.i37.4217
Focus on the gut-brain axis: Multiple sclerosis, the intestinal barrier and the microbiome
Carlos R Camara-Lemarroy, Luanne M Metz, V Wee Yong
Carlos R Camara-Lemarroy, Luanne M Metz, V Wee Yong, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary T2N 2T9, Canada
Carlos R Camara-Lemarroy, Luanne M Metz, V Wee Yong, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary T2N 2T9, Canada
Author contributions: Camara-Lemarroy CR conceived the study and drafted the manuscript; Metz LM and Yong VW revised and approved the final version of the article.
Supported by the Lejoie-Lake Fellowship (to Camara-Lemarroy CR) awarded by the Hotchkiss Brain Institute.
Conflict-of-interest statement: The authors have no conflict of interest to declare.
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: Carlos R Camara-Lemarroy, MD, Academic Fellow, Postdoctoral Fellow, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, 1403 29 Street NW, Calgary T2N 2T9, Canada. carlos.camara-lemarroy@albertahealthservices.ca
Telephone: +1-403-9444253 Fax: +1-403-2707162
Received: July 5, 2018
Peer-review started: July 5, 2018
First decision: July 25, 2018
Revised: July 30, 2018
Accepted: August 1, 2018
Article in press: August 1, 2018
Published online: October 7, 2018

The brain-gut axis serves as the bidirectional connection between the gut microbiome, the intestinal barrier and the immune system that might be relevant for the pathophysiology of inflammatory demyelinating diseases. People with multiple sclerosis have been shown to have an altered microbiome, increased intestinal permeability and changes in bile acid metabolism. Experimental evidence suggests that these changes can lead to profound alterations of peripheral and central nervous system immune regulation. Besides being of pathophysiological interest, the brain-gut axis could also open new avenues of therapeutic targets. Modification of the microbiome, the use of probiotics, fecal microbiota transplantation, supplementation with bile acids and intestinal barrier enhancers are all promising candidates. Hopefully, pre-clinical studies and clinical trials will soon yield significant results.

Keywords: Multiple sclerosis, Microbiome, Intestinal barrier, Bile acids, Gut-brain axis

Core tip: Many studies suggest that the brain-gut connection can contribute to our knowledge of the pathophysiology of neurological conditions. Recent evidence suggests that people with multiple sclerosis have changes in their gut microbiome, their intestinal barrier and even in the metabolism of bile acids. All of these represent relevant therapeutic targets that could feasibly be addressed by pre-clinical and clinical studies. This knowledge acquired in the bench might soon be translated to the bedside.