Similarity of Mast Cell Density and Distribution in Terminal Ileum and Colon of IBD and IBS Patients and Normal Controls

Abstract

Purpose: Background: In vitro and animal studies showed that Mast Cells (MC) are critical element of inflammatory cascade. However, the role of MC in IBD and IBS is still controversial. One possible reason for this controversy is lack of standard method to assess the size of gastrointestinal mucosal MC population in various region of the gastrointestinal tract. Hypoythesis: The number of MC in various part of GI tract is different among subjects with IBD, IBS in comparison to healthy controls. Aim: In this study we tried to evaluate the number of mucosal MC in subjects with IBD, IBS and compare the data with healthy controls. Methods: 24 subjects (8 Controls, 5 inactive IBD, 11 IBS) were studied. Total of 55 biopsy samples were taken during colonoscopy from sigmoid, ascending colon and ileum. Biopsies were stained using immunohistochemical techniques using monoclonal antibody against CD-117. A total of 9 random distinct fields, which were completely covered by transversely cut glands, were selected for MC counting and the mean value was considered as the number of MC per HPF. The counting was done by two independent observer. The number of MC was compared using ANOVA test. Results: There was on average 17 MC per HPF in the ileum, 16 in the ascending colon and 14 in the sigmoid colon. The number of MC in right colon was 20 in IBS-c while this number was 13 in healthy controls and 12 in subjects with IBS-d. However, this difference did not reach statistical significance (p=0.06). The number of MC in other part of the colon and ileum was not significantly different among the subjects group. The inter-observer variability was also not different among the groups. Conclusion: There was no significant difference in the number of MC in various region of lower GI tract in subjects with IBD, IBS compared to healthy counterparts. This may suggest that MC quantity may not be a determining factor in evaluating the role of MC in these disorders. Further studies that assess the function of MC may be more appropriate method of investigating the role of MC in various region of the GI tract in subjects with IBD or IBS.