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Adhesion molecule expression on vascular endothelium and nitroblue tetrazolium reducing activity in human colonic
N Oshitani1, A Campbell, S Bloom
1Gastroenterology Unit, Radcliffe Infirmary, Oxford, UK.
Background:
Expression of adhesion molecules is increased in inflamed colonic mucosa, but little is known about their functional activity in vascular endothelium.
Methods:
We studied in situ nitroblue tetrazolium reducing activity and expression of E-selectin, ICAM-1, CD31, and VCAM-1 by immunohistochemistry in the same biopsy specimen in controls and patients with ulcerative colitis (UC).
Results:
VCAM-1 expression was negative in mucosal vessels. E-selectin-positive vessels were significantly increased in endoscopically active colitis compared with normal mucosa. ICAM-1-positive vessels were consistently found in normal, quiescent UC and active UC. CD31-positive vessels were not significantly increased in quiescent UC and active UC compared with control. Only E-selectin significantly correlated with the histologic grade of inflammation. Nitroblue tetrazolium reducing vessels were increased in inflamed mucosa, and these vessels expressed ICAM-1 and CD31. E-selectin positivity in association with nitroblue tetrazolium reduction was mainly seen in the large mucosal vessels, but capillaries showing nitroblue tetrazolium reduction were rarely positive for E-selectin.
Conclusions:
Phenotypic and functional activation of vascular endothelium might be involved in the recruitment of leukocytes and tissue destruction of inflamed colonic mucosa.