Alternation of mucin structure and lectin binding in the mucosa of ulcerative colitis

Song, Geun Am; Kim, Tae Oh; An, Jin Kwang; Lee, Jun Hong; Kang, Dae Hwan; Cho, Mong; Yang, Ung Suk

Abstract

BACKGROUND
In the pathogenesis of ulcerative colitis, a defective mucosal barrier to luminal antigens is currently under consideration, and alterations in mucin structure and lectin binding may play an important role in the defect of mucosal barrier. It is also, suggested that the differences in clinical manifestation and complication of ulcerative colitis are associated with the change in glycosylation of colonic mucus glycoconjugates. This study was performed in order to investigate the histochemical properties of the mucin in korean ulcerative colitis.
METHODS
The histochemical staining (HID-AB, mild PAS, PBT-KOH-PAS) and the binding of lectin (PNA, DBA, UEA-1, RCA-1, WGA, with avidin-biotin peroxidase complex method) to mucin glycoconjugates were analyzed in paraffin-embedded tissue sections obtained from 14 normal colons and 20 ulcerative colitis.
RESULTS
In the ulcerative colitis, number of goblet cell and amount of mucin were decreased, but the expression of its sulphomucin was consistently predominant and strong like normal colon. The expression of N-acetylated sialomucin was more common in the ulcerative colitis(80%) than normal colon(50%) and its grading mildly increased in ulcerative colitis. The expression of O-acetylated sialomucin was present in all cases of normal colon and its staining grade decreased in the ulcerative colitis. Compared to normal colonic mucosa, ulcerative colitis showed the increase in PNA and DBA binding in the supranuclear cytoplasm, the decrease in DBA and RCA-1 binding in the goblet cells, and no change in UEA-1 and WGA binding in both. In the ulcerative colitis, the increase in PNA and DBA binding was mild in the supranuclear cytoplasm and the expression of DBA and RCA-1 binding in goblet cells variably decreased. CONCLUSIONS: This study demonstrates the changes in the mucosal glycoconjugates between the ulcerative colitis and normal colon. The mucinous glycoconjugate expression of korean ulcerative colitis are different from that of western patients. There may be a genetic, racial variation in the glycoconjugate, which may also play a part in the differences in pathogenesis, clinical manifestation, and complication of ulcerative colitis.