Ulcerative colitis (UC) is an idiopathic and chronic inflammatory disorder of the colonic mucosa. Damage to epithelial barrier function due to ulceration and colitis leads to increased permeability of the intestine. This barrier loss causes increased uptake of luminal antigens such as endotoxin (ET). We evaluated ET levels detected by Endotoxin activity assay (EAA) in patients with UC. We measured EAA 8 cases (refractory UC 6 and cancer/dysplasia UC 2) of UC required surgical treatments. Various clinicopathological parameters were reviwed. The severity of UC was evaluated by Seo’s index. Pre-operative EAA was 0.14 in patients with cancer/dysplasia UC and 0.4 in patients with refractory UC. EAA levels increased according to severity of UC, mild 0.095, moderate 0.39, severe 0.42 without statistical significance. There was a significantly positive relationship between EAA and Seo’s index (Spearman’s rank correlation coefficient 0.8333, p=0.0102). EAA appeared to be useful biomarker to evaluate patients’severity with UC. Large scale study need to clarify the significance of EAA in patients with UC.
