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World J Gastroenterol. Jan 14, 2014; 20(2): 384-400
Published online Jan 14, 2014. doi: 10.3748/wjg.v20.i2.384
Is irritable bowel syndrome an organic disorder?
Magdy El-Salhy, Doris Gundersen, Odd Helge Gilja, Jan Gunnar Hatlebakk, Trygve Hausken
Magdy El-Salhy, Section for Gastroenterology, Department of Medicine, Stord Helse-Fonna Hospital, 5409 Stord, Norway
Magdy El-Salhy, Odd Helge Gilja, Jan Gunnar Hatlebakk, Trygve Hausken, Section for Gastroenterology, Department of Clinical Medicine, University of Bergen 5006 Bergen, Norway
Doris Gundersen, Department of Research, Helse-Fonna, 5528 Haugesund, Norway
Author contributions: El-Salhy M collected the literature data and wrote the manuscript; Gundersen D, Gilja OH, Hatlebakk JG and Hausken T contributed equally to discussions about the collected data and commented upon the manuscript; all of the authors approved the submitted version of the manuscript.
Supported by A grant from Helse-Fonna
Correspondence to: Magdy El-Salhy, Professor, Consultant Gastroenterologist, Section for Gastroenterology, Department of Medicine, Stord Helse-Fonna Hospital, Karmsundgata 120, Box 4000, 5409 Stord, Norway. magdy.el-salhy@helse-fonna.no
Telephone: +47-5-3491000 Fax: +47-5-3491000
Received: September 27, 2013
Revised: November 5, 2013
Accepted: November 12, 2013
Published online: January 14, 2014
Abstract

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is generally considered to be functional because there appears to be no associated anatomical defect. Stress and psychological factors are thought to play an important role in IBS. The gut neuroendocrine system (NES), which regulates all functions of the gastrointestinal tract, consists of endocrine cells that are scattered among the epithelial cells of the mucosa, and the enteric nervous system. Although it is capable of operating independently from the central nervous system (CNS), the gut NES is connected to and modulated by the CNS. This review presents evidence for the presence of an anatomical defect in IBS patients, namely in the gastrointestinal endocrine cells. These cells have specialized microvilli that project into the lumen and function as sensors for the luminal content and respond to luminal stimuli by releasing hormones into the lamina propria, which starts a chain reaction that progresses throughout the entire NES. The changes in the gastrointestinal endocrine cells observed in IBS patients are highly consistent with the other abnormalities reported in IBS patients, such as visceral hypersensitivity, dysmotility, and abnormal secretion.

Keywords: Cholecystokinin, Dysmotility, Endocrine cells, Enteric nervous system, Ghrelin, Peptide YY, Secretion, Secretin, Serotonin, Visceral hypersensitivity

Core tip: This review presents recent observations in irritable bowel syndrome (IBS) patients that point toward the existence of an anatomical defect in the gastrointestinal endocrine cells. It includes also an argument that IBS is an organic disorder and that the abnormalities in the gastrointestinal endocrine cells can explain the visceral hypersensitivity, dysmotility and abnormal secretion reported in these patients.