ROLE OF ENDOTHELIAL ADHESION MOLECULES IN NSAID-INDUCED GASTRIC-MUCOSAL INJURY

A number of recent studies have demonstrated that neutrophil adherence to the vascular endothelium is a critical early event in the pathogenesis of gastric mucosal injury induced by nonsteroidal anti-inflammatory drugs (NSAIDs). Although a role in this process for the leukocyte adhesion molecule, CD11/CD18, has been demonstrated, the involvement of endothelial adhesion molecules has not previously been examined. Therefore, using monoclonal antibodies directed against a number of endothelial adhesion molecules (ICAM-1, P-selectin, E-selectin), we studied the role of these molecules in the production of mucosal injury after indomethacin administration and in indomethacin-induced leukocyte adherence. As previously shown in the rabbit, anti-CD18 markedly reduced (by 75%) the severity of damage induced by indomethacin in the rat. Moreover, this antibody completely prevented indomethacin-induced leukocyte adherence. Similarly, anti-ICAM-1 significantly attenuated (by 74%) the severity of indomethacin-induced gastric injury while also markedly reducing leukocyte adherence (by 83%). Anti-P-selectin and anti-E-selectin produced only small (approximately 35%), but statistically significant, reductions of mucosal injury, but only anti-P-selectin significantly affected indomethacin-induced leukocyte adherence (by approximately 50%). These results demonstrate that indomethacin-induced leukocyte adherence and mucosal injury are dependent on the expression of CD18 and ICAM-1. P-selectin also appears to play a small, but important, role in these processes, whereas the role of E-selectin remains equivocal. These studies support the hypothesis that interactions at the leukocyte-endothelium interface are critical in the pathogenesis of NSAID-induced mucosal injury, and this interface may represent a rational target for therapies aimed at preventing this form of injury.