Mucosal proinflammatory cytokine production correlates with endoscopic activity of ulcerative colitis

Proinflammatory cytokines are believed to be involved in the pathogenesis of ulcerative colitis (UC). The aim of this study was to clarify the profiles of proinflammatory cytokine production in patients with UC in terms of disease intractability, endoscopic findings, and host response to lipopolysaccharide (LPS) stimulation. Colonic mucosal tissues were obtained from patients with active UC (n = 15, including 4 patients with intractable disease) and inactive UC (n = 7), non-inflammatory bowel disease (IBD) colitis (n = 11), and controls (n = 20). Organ culture was performed, and the amounts of four cytokines (described below) in the culture media were determined by enzyme-linked immunosorbent assay (ELISA). LPS stimulation enhanced interleukin (IL)-1β, IL-8, and IL-6 production in colonic specimens from all groups, but enhanced tumor necrosis factor (TNF)-α production only in active UC specimens. Levels of IL-6, IL-8, and TNF-α were significantly higher in active UC than in non-IBD colitis, and the production of all three of these cytokines was correlated to the endoscopic grade of inflammation. The production of these cytokines was also significantly higher in patients with intractable disease receiving corticosteroids than in patients with non-intractable disease receiving corticosteroids. These results suggest that enhanced production of mucosal proinflammatory cytokines may be implicated in the pathogenesis of UC.