Thromboxane synthase immunohistochemistry in inflammatory bowel disease.

BACKGROUND Thromboxanes are produced in excess in inflammatory bowel disease. Preliminary reports suggest that ridogrel, a thromboxane synthase inhibitor, is anti-inflammatory and may have therapeutic benefits in patients with ulcerative colitis. AIMS To investigate the immunohistochemical expression of thromboxane synthase in the colorectal mucosa of patients with inflammatory bowel disease. METHODS Immunostaining of colonic biopsies from patients with inflammatory bowel disease (n = 13) and controls (n = 5) was performed using a monoclonal antibody to human thromboxane synthase. The extent of staining in cells of the lamina propria was compared in patient and control groups, and was assessed in relation to disease activity scored macroscopically and histologically. RESULTS The percentage of cells in the lamina propria staining for thromboxane synthase was higher in patients with active inflammatory bowel disease than in those with inactive disease or in controls (p = 0.02 and p = 0.002, respectively). There was a direct correlation between disease activity, measured endoscopically and histologically, and the percentage of lamina propria cells staining for thromboxane synthase (R = 0.71, p = 0.001 and R = 0.72, p = 0.001, respectively). CONCLUSIONS Increased thromboxane synthase expression in lamina propria cells occurs in active inflammatory bowel disease. It is possible that this results in increased thromboxane synthesis, which may in turn contribute to mucosal inflammation and intramucosal thrombogenesis.