NSAIDs upregulate beta(2)-integrin expression on human neutrophils through a calcium-dependent pathway

Background: Margination of circulating neutrophils (PMN) into the gastric microcirculation is an early and critical event in the pathogenesis of non-steroidal antinflammatory drug (NSAID)-induced gastropathy. This effect is mediated through the upregulation of beta(2) integrins on the PMN surface. Aims: To investigate whether indomethacin modulates: (1) Mac-1 expression; (2) Ca2+ mobilization ([Ca2+](i)), protein kinase C and nitric oxide accumulation; and (3) mitogen-associated protein kinase phosphorylation in human PMN. Methods: Human PMN were isolated by centrifugation through a double Ficoll gradient. [Ca2+](i) was measured in PMN loaded with fura-2 and Mac-1 expression by flow cytometry. Results: Indomethacin caused a concentration- and time-dependent upregulation of CD11b and CD18 expression and PMN adhesion to endothelial cells, Maximal upregulation of Mac-1 expression (40-50%) occurred after a 30-min incubation with 0.1 mM.