Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Dec 7, 2016; 22(45): 9871-9879
Published online Dec 7, 2016. doi: 10.3748/wjg.v22.i45.9871
Gastrointestinal neuromuscular apparatus: An underestimated target of gut microbiota
Michele Pier Luca Guarino, Michele Cicala, Lorenza Putignani, Carola Severi
Michele Pier Luca Guarino, Michele Cicala, Digestive Disease Unit of Campus Bio Medico University of Rome, 00128 Rome, Italy
Lorenza Putignani, Unit of Parasitology, Bambino Gesù Children’s Hospital, IRCCS, 00100 Rome, Italy
Carola Severi, Department of Internal Medicine and Medical Specialties, University Sapienza, 00100 Rome, Italy
Author contributions: The authors contributed equally to this work.
Conflict-of-interest statement: The author has no conflict of interests.
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: Michele Pier Luca Guarino, MD, PhD, Digestive Disease Unit of Campus Bio Medico University of Rome, Via Alvaro del Portillo 200, 00128 Rome, Italy. m.guarino@unicampus.it
Telephone: +39-6-22541606 Fax: +39-6-22541456
Received: July 29, 2016
Peer-review started: August 2, 2016
First decision: September 28, 2016
Revised: October 13, 2016
Accepted: November 14, 2016
Article in press: November 16, 2016
Published online: December 7, 2016

Over the last few years, the importance of the resident intestinal microbiota in the pathogenesis of several gastro-intestinal diseases has been largely investigated. Growing evidence suggest that microbiota can influence gastro-intestinal motility. The current working hypothesis is that dysbiosis-driven mucosal alterations induce the production of several inflammatory/immune mediators which affect gut neuro-muscular functions. Besides these indirect mucosal-mediated effects, the present review highlights that recent evidence suggests that microbiota can directly affect enteric nerves and smooth muscle cells functions through its metabolic products or bacterial molecular components translocated from the intestinal lumen. Toll-like receptors, the bacterial recognition receptors, are expressed both on enteric nerves and smooth muscle and are emerging as potential mediators between microbiota and the enteric neuromuscular apparatus. Furthermore, the ongoing studies on probiotics support the hypothesis that the neuromuscular apparatus may represent a target of intervention, thus opening new physiopathological and therapeutic scenarios.

Keywords: Microbiota, Gastrointestinal motility, Smooth muscle, Enteric nervous system, Probiotics, Irritable bowel syndrome

Core tip: This article reviews the current evidence of gut microbiota and neuromuscular apparatus connection that results to be both direct and indirect. Besides dysbiosis-driven mucosal inflammatory mediators, recent evidence suggests that gut neuromuscular apparatus can be modulated directly by microbiota metabolic products or circulating bacterial molecular components translocated from the intestinal lumen.