Sulphomucin expression in ileal pouches: emerging differences between ulcerative colitis and familial adenomatous polyposis pouches.

Abstract

PURPOSE: We characterized the expression of sialomucin and sulphomucin in pouches fashioned for familial adenomatous polyposis and ulcerative colitis. We correlated sulphomucin expression with bacterial colonization and mucosal inflammation. METHODS: Ethical approval and informed consent were obtained. Mucosal biopsies from 9 patients with familial adenomatous polyposis and 12 with ulcerative colitis were obtained. Sulphomucin levels were assessed by using the high iron-diamine stain. Mucous gel layer composition was correlated with villous height, crypt depth, and total mucosal thickness. Mucous gel layer composition was correlated with acute and chronic inflammatory infiltrates. Colonization by a panel of seven bacterial species (including sulphate reducing bacteria) was established and correlated with sulphomucin levels. RESULTS: High-iron-diamine positivity (i.e., sulphomucin expression) was greater in ulcerative colitis pouch mucous gel (2.083 +/- 0.5 vs. 0.556 +/- 0.4, P = 0.003). Sulphomucin expression correlated with reduced crypt depth, villous height, and total mucosal thickness. In the ulcerative colitis group, chronic inflammatory infiltrate scores were significantly greater for high-iron-diamine-positive patients. Colonization by sulphate reducing bacteria was increased in high-iron-diamine-positive patients. CONCLUSIONS: Sulphomucin expression is increased in the mucous gel layer of the ulcerative colitis pouch compared with that of the familial adenomatous polyposis pouch. Sulphomucin expression is associated with colonization by sulphate-reducing bacteria and increased chronic inflammation.