[NSAIDs caused gastric mucosal injury: with a special reference to COX-2]

Nonsteroidal antiinflammatory drugs (NSAIDs) have been shown to cause mucosal injury in the gastrointestinal tract as a side effect, occasionally turning out to be severe complications such as bleeding and perforation. So far NSAIDs-caused mucosal injury was attributed to their inhibitory effects on the activity of cyclooxygenase-1 (COX-1) which is expressed and shown to play a crucial role for the mucosal protection via producing prostaglandin E2 in the stomach. However, a recent progress of the understanding about COX physiology has revealed that NSAIDs cause gastric mucosal injury by inhibiting not only COX-1 but also COX-2 in the stomach. COX-1 inhibition alone has been demonstrated not to cause gastric mucosal injury. In addition, a selective COX-2 inhibitor which is demonstrated to have much less harmful effect in the stomach is now widely used as a safer NSAID in USA. Moreover, a selective COX-2 inhibitor is recently considered to have an inhibitory effect on growth of a certain type of cancers, thereby being in the spotlight as a chemopreventive agent.