NEUTROPHIL ELASTASE ENHANCES INTERCELLULAR-ADHESION MOLECULE-1 EXPRESSION

Background. Elastase released from activated neutrophils is an importa nt mediator of inflammatory tissue damage. We investigated the effect of human neutrophil elastase (NE) inhibitor (ONO-5046) on reperfusion injury after pancreaticoduodenal transplantation in rats by measuring the expression of intercellular adhesion molecule-1 (ICAM-1), Addition al in vitro experiments were conducted to investigate the effect of NE on ICAM-1 mRNA transcription in a rat endothelial cell line (WK-5) an d human umbilical vein endothelial cells (HUVEC). Methods. In am in vi vo experiment, male Wister rats were transplanted with syngeneic pancr eaticoduodenal grafts. An NE inhibitor, ONO-5046, was injected intrave nously 5 min before vascular clamping and immediately after reperfusio n at a dose of 10 mg/kg, ICAM-1 expression was determined by immunosta ining and Northern analysis. In in vitro experiments, the effects of N E and chemical agents on ICAM-1 mRNA transcripts were determined in WK -5 cells and HUVEC. Results. Pretreatment with ONO-5046 decreased ICAM -1 immunostaining in the pancreatic graft and inhibited the increase i n ICAM-1 mRNA levels in grafts after reperfusion. ICAM-1 mRNA levels i n WK-5 cells and HUVEC showed stimulation by NE, while ONO-5046 inhibi ted this increase. Calcium ionophore (A23187) augmented NE stimulation of ICAM-1 mRNA levels in these cells, in contrast, a phospholipase C inhibitor (U73122) blunted NE induction of ICAM-1 mRNA, and either cal cium chelator (TMB-8) or a nuclear factor-kappa B inhibitor (pyrrolidi ne dithiocarbamate) completely inhibited induction. Conclusion. These results indicate that NE stimulates ICAM-1 expression in pancreatic gr afts via intracellular Ca2+ influx and a phospholipase C signal transd uction.