Phospholipase A2 activity of colonic mucosa in patients with ulcerative colitis.

Activation of enzyme phospholipase A2 (EC 3.1.1.4), the major liberator of arachidonic acid, has been proposed as a component in the pathogenesis of inflammatory bowel disease. To test the hypothesis that phospholipase A2 activity is increased in ulcerative colitis, enzyme activity was investigated in colonic biopsies using radiolabelled Escherichia coli as substrate. The study comprised patients with ulcerative colitis (n = 19) and controls without inflammatory bowel disease (n = 7). Ulcerative colitis patients were grouped into those with active disease (n = 8) and those in remission (n = 11) at the time of colonoscopy. No differences were found in mucosal phospholipase A2 activity between patients with active disease, patients in remission and controls. With the present assay we were unable to demonstrate activation of phospholipase A2 as a mechanism in the inflammatory process of ulcerative colitis.