Case Control Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Aug 28, 2015; 21(32): 9577-9587
Published online Aug 28, 2015. doi: 10.3748/wjg.v21.i32.9577
Reduction in duodenal endocrine cells in irritable bowel syndrome is associated with stem cell abnormalities
Magdy El-Salhy, Jan Gunnar Hatlebakk, Trygve Hausken
Magdy El-Salhy, Jan Gunnar Hatlebakk, Trygve Hausken, Section for Neuroendocrine Gastroenterology, Division of Gastroenterology, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway
Magdy El-Salhy, Jan Gunnar Hatlebakk, Trygve Hausken, National Centre for Functional Gastrointestinal Disorders, Department of Medicine, Haukeland University Hospital, 5020 Bergen, Norway
Magdy El-Salhy, Section for Gastroenterology, Department of Medicine, Stord Hospital, 5409 Stord, Norway
Author contributions: El-Salhy M planned the study, recruited the patients, performed gastroscopies, analyzed the data and drafted the manuscript; Hatlebakk JG and Hausken T checked the study plan, read the manuscript and contributed to interpretation and analysis of the results; all authors approved the version of the article to be published.
Supported by Helse-Vest and Helse-Fonna, Norway.
Institutional review board statement: The local Committee for Medical and Health Research Ethics West, Norway approved the study.
Informed consent statement: All the participants provided informed written consent prior to study enrollment.
Conflict-of-interest statement: Magdy El-Salhy and Trygve Hausken have served as advisory board members for Shire and Almirall.
Data sharing statement: Technical appendix, statistical code, and dataset available from the corresponding author at magdy.el-salhy@helse-fonna.no.
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: Magdy El-Salhy, Professor, Consultant Gastroenterologist, Section for Gastroenterology, Department of Medicine, Stord Hospital, Box 4000, 5409 Stord, Norway. magdy.el-salhy@helse-fonna.no
Telephone: +47-53-491001 Fax: +47-53-491000
Received: December 10, 2014
Peer-review started: December 11, 2014
First decision: January 22, 2015
Revised: February 9, 2015
Accepted: April 3, 2015
Article in press: April 3, 2015
Published online: August 28, 2015
Abstract

AIM: To determine whether the decreased density of duodenal endocrine cells in irritable bowel syndrome (IBS) is associated with abnormalities in stem cell differentiation.

METHODS: The study sample comprised 203 patients with IBS (180 females and 23 males with a mean age of 36 years) and a control group of 86 healthy subjects without gastrointestinal complaints (77 females and 9 males with a mean age of 38 years). The patients included 80 with mostly diarrhoea (IBS-D), 47 with both diarrhoea and constipation (IBS-M), and 76 with mostly constipation (IBS-C). Both the patients and controls underwent gastroscopy and four biopsy samples were taken from the descending part of the duodenum, proximal to the papilla of Vater. The biopsy samples were sectioned and immunostained for Musashi 1 (Msi-1), neurogenin 3 (NEUROG3), secretin, cholecystokinin (CCK), gastric inhibitory peptide (GIP), somatostatin and serotonin. Immunostaining was performed with an ultraView Universal DAB Detection Kit (v1.02.0018, Venata Medical Systems, Basal, Switzerland) using the BenchMark Ultra immunohistochemistry/in situ hybridization staining module (Venata Medical Systems). Endocrine cell densities were quantified by computerized image analysis using the Olympus cellSens imaging program.

RESULTS: The densities of Msi-1 and NEUROG3 cells were significantly lower in IBS patients, regardless of the subtype, than in the controls (77 ± 17 vs 8 ± 2; P = 0.0001, and 351 ± 33 vs 103 ± 22; P = 0.00002, respectively). Furthermore, the densities of secretin, and CCK cells were significantly lower in patients with diarrhoea as the predominant IBS symptom (IBS-D) than in the controls (161 ± 11 vs 88 ± 8; P = 0.00007, and 325 ± 41 vs 118 ± 10; P = 0.00006, respectively), but not in patients with constipation as the predominant IBS symptom (IBS-C) or those with both diarrhoea and constipation (IBS-M). The GIP cell density was significantly reduced in both IBS-D (152 ± 12 vs 82 ± 7; P = 0.00003), and IBS-C (152 ± 12 vs 107 ± 8; P = 0.01), but not in IBS-M. The densities of somatostatin cells in the controls and the IBS-total, IBS-D, IBS-M and IBS-C patients were 81 ± 8, 28 ± 3, 20 ± 4, 37 ± 5 and 28 ± 4 cells/mm2 epithelium, respectively. The density of somatostatin cells was lower in IBS-total, IBS-D, IBS-M and IBS-C patients than in the controls (P = 0.00009, 0.00006, 0.009 and 0.00008, respectively). The density of serotonin cells did not differ between IBS patients and controls.

CONCLUSION: The reduction in duodenal endocrine cells in IBS patients found in this study is probably attributable to the reduction in cells expressing Msi-1 and NEUROG3.

Keywords: Cholecystokinin, Irritable bowel syndrome, Musashi-1, Neurogenin 3, Secretin, Somatostatin

Core tip: Musashi 1 (Msi-1) is a marker for both intestinal stem cells and their early progeny, and neurogenin 3 (NEUROG3) is a marker for early intestinal endocrine cell progenitors. The densities of Msi-1 and NEUROG3 cells were reduced in the duodenum of patients with irritable bowel syndrome (IBS), regardless of the subtype, indicating disturbances in both the clonogenic renewal of small intestine stem cells and their proliferation toward endocrine cells. It is most likely that the reduction in the duodenal endocrine cells in patients with IBS is caused by an abnormality in the stem cell clonogenic and proliferation activities.