Effect of Helicobacter pylori eradication on cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression during gastric adaptationto aspirin (ASA) in humans

Gastric adaptation to aspirin is impaired in Helicobacter pylori infection, but the mechanisms underlying this phenomenon are unclear. In this study, we compared gastric mucosal expression of iNOS and COX-2 during 14 days of aspirin ingestion in the same subjects before and 3 months after eradicatio n of H. pylori. Compared to non-infected controls, mucosal expression of CO X-2 and iNOS was enhanced before and 3 months after eradication of H. pylor i. During aspirin ingestion, mucosal expression of COX-2 remained unchanged before eradication of H. pylori, but increased gradually after successful antimicrobial treatment. Independent of H. pylori status, expression of iNO S increased at the beginning of aspirin intake, but then returned to initia l values. We conclude that COX-2 but not iNOS might be involved in gastric adaptation to aspirin in humans and that this mechanism appears to be impai red in H. pylori infection. (C) 2001 Wiley-Liss, Inc.