# Diarrhoea-predominant IBS patients show mast cell activation



## eric (Jul 8, 1999)

Gut. 2006 Sep 27; [Epub ahead of print] Links Diarrhoea-predominant IBS patients show mast cell activation and hyperplasia in the jejunum.Guilarte M, Santos J, de Torres I, Alonso C, Vicario M, Ramos L, Martinez C, Casellas F, Saperas E, Malagelada JR. Hospital Universitari Vall d'Hebron, Universitat Autonoma de Barcelona, Spain.BACKGROUND: Increased number of mast cells and mast cell activation in distal gut segments have been associated with symptom onset and severity in irritable bowel syndrome (IBS). Although, upper gut symptoms are also common in IBS, mast cells have not been thoroughly evaluated in the proximal gut of IBS. METHODS: Jejunal biopsies obtained by Watson's capsule, aspiration of intestinal fluid and one blood sample were obtained in 20 diarrhea-prone IBS (D-IBS) and 14 healthy volunteers (H). Psychological stress (Holmes- Rahe Scale) and depression (Beck's Inventory) were evaluated at baseline and food and respiratory allergy excluded. Biopsies were processed for hematoxylin & eosin staining and microscopic inflammation assessed by numbering intraepithelial lymphocytes. In addition, mast cells in the lamina propria were counted by immunohistochemistry with CD117 (c-kit). Tryptase concentration was measured in both intestinal fluid and serum. RESULTS: D-IBS patients showed higher psychological stress than healthy (D-IBS: 203 +/- 114 vs. H: 112 +/- 99; p=0.019). Jejunal mucosa from both groups appeared normal on routine histopathology but immunohistochemical staining revealed a mild increase in intraepithelial CD3+cells in D-IBS (D-IBS: 15.3 +/- 5.5 [12.7-17.9] vs. H: 10.3 +/- 3.9 [8.0-12.5]; p=0.006). Moreover, D-IBS showed a marked increase in mast cells numbers (D-IBS: 34 +/- 9.3; H: 15.3 +/- 4.4 mast cells/hpf; p<0.0001), a finding paralleled by higher tryptase concentration in jejunal fluid (D-IBS: 0.45 +/- 0.38; H: 0.09 +/- 0.10 microg/L; p=0.005). Upper gut symptoms were not associated to gender, mast cell counts, jejunal tryptase or basal stress. CONCLUSION: This jejunal mucosal inflammatory profile may be helpful for the identification of D-IBS, a stress-related disorder.PMID: 17005763


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