Reduction in duodenal endocrine cells in irritable bowel syndrome is associated with stem cell abnormalities.
OBJECTIVE
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/mm(2) 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.


CONCLUSIONS
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.
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
M
El-Salhy
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.
Jan Gunnar
JG
Hatlebakk
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.
Trygve
T
Hausken
D000293:Adolescent; D000328:Adult; D000368:Aged; D051792:Basic Helix-Loop-Helix Proteins / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D001706:Biopsy; D016022:Case-Control Studies; D002454:Cell Differentiation; D004386:Duodenum / Q000737:chemistry / Q000473:pathology*; D019858:Enteroendocrine Cells / Q000737:chemistry / Q000473:pathology*; D005260:Female; D005773:Gastroscopy; D006801:Humans; D007150:Immunohistochemistry; D043183:Irritable Bowel Syndrome / Q000378:metabolism / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000032:analysis; D010641:Phenotype; D016601:RNA-Binding Proteins / Q000032:analysis; D013234:Stem Cells / Q000737:chemistry / Q000473:pathology*; D055815:Young Adult
D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D009419:Nerve Tissue Proteins; D016601:RNA-Binding Proteins; C491297:MSI1 protein, human; C498695:NEUROG3 protein, human
Cholecystokinin; Irritable bowel syndrome; Musashi-1; Neurogenin 3; Secretin; Somatostatin