The anti-inflammatory drug nimesulide inhibits neutrophil adherence to and migration across monolayers of cytokine-activated endothelial cells.

Abstract

Neutrophil migration through the microvascular endothelium represents a fundamental event for the cell accumulation at sites of tissue injury. Owing to their capacity to modify the structural and functional characteristics of endothelial cells, inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF alpha) play a pivotal role in directing circulating neutrophils away from the bloodstream to the interstitial tissue. In order to study neutrophil transendothelial migration, human umbilical vein endothelial cells were grown to confluence on the polycarbonate filter of two-compartment migration chambers. Pretreatment of the endothelial cell monolayers with TNF alpha for 4 h resulted in rapid migration of approximately 50% of subsequently added neutrophils across the layers. In contrast, < 10% of added neutrophils penetrated untreated endothelial monolayers. Using TNF alpha-treated endothelium, neutrophil transmigration was inhibited by the methane sulfonanilide anti-inflammatory drug nimesulide. Moreover, neutrophil adherence to TNF alpha-treated endothelial monolayers, cultured in microtiter wells, was markedly reduced by nimesulide. A linear correlation between the drug-dependent inhibition of neutrophil transmigration and neutrophil adherence was found. Finally, nimesulide did not interfere with the TNF alpha ability to convert resting endothelium into a pro-adhesive and pro-locomotory cell layer. The data suggest that nimesulide reduces neutrophil transendothelial migration primarily by limiting the cell anchorage to the TNF alpha-activated endothelium. Therefore, the drug has the potential to down-regulate neutrophil extravasation and, in turn, the burden of neutrophil oxidants and proteases leading to tissue injury at sites of inflammation.