title: Mucosal mast cell count is associated with intestinal permeability in patients with diarrhea predominant irritable bowel syndrome.
abstract: OBJECTIVE
  Although mucosal mast cell tryptase is known to significantly increase intestinal permeability, the relationship between mucosal mast cells and intestinal permeability remains unclear. The objective of this study was to evaluate the correlation among intestinal permeability, tryptase activity and mucosal mast cell count.
  
  
  METHODS
  Rectal biopsies from 16 patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and 7 normal subjects were assessed for tryptase activity and macromolecular permeability using horseradish peroxidase in Ussing chambers. In addition, mucosal mast cell levels were immunohistochemically quantified via image analysis.
  
  
  RESULTS
  Rectal biopsy of tissues from IBS-D patients showed significantly increased permeability compared with those from normal controls (0.644 ± 0.08 and 0.06 ± 0.00 ng/2 hr/mm(2), P < 0.01). Tryptase activity was also substantially higher in rectal biopsy samples from IBS-D patients than those from normal controls (0.86 ± 0.18 and 0.28 ± 0.04 mU/mg protein, P < 0.05). Mucosal mast cell counts were not significantly different between the 2 groups (P > 0.05). However, correlation analysis revealed that only mucosal mast cell count was significantly correlated with intestinal permeability in IBS-D patients (r = 0.558, P < 0.05).
  
  
  CONCLUSIONS
  This study demonstrated a positive correlation between the number of mucosal mast cells and intestinal permeability, suggesting that mucosal mast cells play an important role for increased intestinal permeability in patients with IBS-D.
authors.affiliation: Department of Internal Medicine and Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Lee
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Park
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Park
authors.forename: Hong Joo
authors.initials: HJ
authors.lastname: Kim
authors.forename: Yong Kyun
authors.initials: YK
authors.lastname: Cho
authors.forename: Chong Il
authors.initials: CI
authors.lastname: Sohn
authors.forename: Woo Kyu
authors.initials: WK
authors.lastname: Jeon
authors.forename: Byung Ik
authors.initials: BI
authors.lastname: Kim
authors.forename: Seoung Wan
authors.initials: SW
authors.lastname: Chae
keywords: Irritable bowel syndrome; Mast cell, Permeability; Tryptase