Low densities of serotonin and peptide YY cells in the colon of patients with irritable bowel syndrome.

BACKGROUND: The gut hormones are important in regulating gastrointestinal motility. Disturbances in gastrointestinal motility have been reported in patients with irritable bowel syndrome (IBS). Reduced endocrine cell density, as revealed by chromogranin A, has been reported in the colon of IBS patients. AIMS: To investigate a possible abnormality in the colonic endocrine cells of IBS patients. METHODS: A total of 41 patients with IBS according to Rome Criteria III and 20 controls were included in the study. Biopsies from the right and left colon were obtained from both patients and controls during colonoscopy. The biopsies were immunostained for serotonin, peptide YY (PYY), pancreatic polypeptide (PP), entroglucagon, and somatostatin cells. Cell densities were quantified by computerized image analysis. RESULTS: Serotonin and PYY cell densities were reduced in the colon of IBS patients. PP, entroglucagon, and somatostatin-immunoreactive cells were too few to enable reliable quantification. CONCLUSION: The cause of these observations could be primary genetic defect(s), secondary to altered serotonin and/or PYY signaling systems and/or subclinical inflammation. Serotonin activates the submucosal sensory branch of the enteric nervous system and controls gastrointestinal motility and chloride secretion via interneurons and motor neurons. PYY stimulates absorption of water and electrolytes, and inhibits prostaglandin (PG) E2, and vasoactive intestinal peptide, which stimulates intestinal fluid secretion and is a major regulator of the "ileal brake". Although the cause and effect relationship of these findings is difficult to elucidate, the abnormalities reported here might contribute to the symptoms associated with IBS.

High chromogranin A cell density in the colon of patients with lymphocytic colitis.

Microscopic colitis (MC) is a chronic condition that is characterized by watery diarrhoea with normal appearance of the colonic mucosa. MC is subdivided into two distinctive entities: lymphocytic colitis (LC) and collagenous colitis (CC). The etiology and pathophysiology of LC remain to be determined. The present study included 9 female patients with LC, with an average age of 34 years. Subjects (n=25) who underwent colonoscopy were used as controls. The subjects underwent colonoscopy due to gastrointestinal bleeding, where the source of bleeding was identified as haemorrhoids, or due to health concerns. The control subjects included 18 females and 7 males, with an average age of 49 years. Colonoscopy was performed in both patient and control groups, and biopsies were obtained from different segments of the colon. The biopsies were immunostained with the avidin-biotin complex method for human leucocytes CD45, collagen type III and chromogranin A (CgA). CgA was quantified by computer image analysis. The density of CgA-immunoreactive cells in patients with LC was significantly higher than that in controls. The high density of colonic CgA, a common marker for endocrine cells, indicates the possibility that colonic hormones are involved in the pathophysiology of LC. Serotonin-containing cells are the major endocrine cell type in the colon and constitute approximately 88% of the total endocrine cell population. It is likely that the increase in colonic CgA in LC patients accounts for an increase in serotonin cells.

The prevalence of celiac disease in patients with irritable bowel syndrome.

The diagnosis of irritable bowel syndrome (IBS) is based on symptom assessment such as the Rome III criteria. It is sometimes difficult to clinically distinguish IBS from adult-onset celiac disease (CD). Individuals with CD presenting with relatively vague abdominal symptoms are at risk of been dismissed as having IBS. This study aimed to investigate the prevalence of patients with CD among those that fulfill the Rome III criteria for IBS from among patients referred to the gastroenterology section of our hospital over the last 5 years. The study included a total of 968 patients with an average age of 32 years (range 18-59 years). Females constituted 95% of all patients. Duodenal biopsies were obtained during standard gastroscopy. Sections from these biopsies were stained with haematoxylin and eosin and immunostained for human leucocytes CD45 using the avidin-biotin complex (ABC) method. The sections were then histopathologically examined. Four patients had CD: one with Marsh type 3b, and 3 with Marsh type 1. All four of these patients were positive for tissue transglutminase antibodies (anti-t-TG) IgA and were females aged 24, 20, 36 and 38 years. These 4 patients fulfilled the Rome III criteria for the sub-type IBS-diarrhea. This amounts to a prevalence of 0.4% of CD in IBS patients. The present findings support the notion that IBS patients should be routinely examined for CD. This applies to all subtypes of IBS.