Prostaglandin biology in inflammatory bowel disease

Prostaglandins are critical mediators of virtually every aspect of mucosal defense, explaining in part why nonsteroidal antiinflammatory drugs are able to cause injury throughout the gastrointestinal tract. When inflamed, gastrointestinal prostaglandin synthesis is derived largely from cyclooxygenase-2, in contrast to the normal situation. These prostaglandins play an important role in down-regulating inflammation and in promoting repair. Selective suppression of COX-2 has been shown, in experimental models, to cause an exacerbation of colitis and to increase the propensity for bacterial invasion of the intestinal mucosa.