Contribution of Endothelin-1 to Microcirculatory Impairment in Total Hepatic Ischemia and Reperfusion Injury

BACKGROUND: Endothelin (ET)-1 may have a role in hepatic polymorphonuclear leukocyte infiltration as well as microcirculatory disturbance during hepatic ischemia-reperfusion (HIR) injury. This study was conducted to investigate the influence of ET-1 on the hepatic microcirculation after total HIR and to evaluate the effect of a nonselective ET receptor antagonist under these conditions. METHODS: Male rats pretreated with either normal saline (NS group) or TAK-044, a nonselective ET receptor antagonist (TAK group), were subjected to 120 min of total hepatic ischemia with extracorporeal portosystemic shunting. RESULTS: Plasma ET-1 levels increased significantly from 1 to 6 hr after reperfusion in the NS group when compared with the nonischemic control. In the early phase of reperfusion, the NS group showed significantly narrower sinusoids, lower hepatic tissue blood flow, a lower hepatic tissue oxy-hemoglobin concentration, and more hepatic neutrophil infiltration than the TAK group (P<0.05). Pretreatment with TAK-044 improved hepatic microcirculatory derangement, and resulted in significantly better 7-day survival (61.5%) with more bile production after reperfusion when compared with the NS group (P<0.01). CONCLUSIONS: The present study demonstrated that ET-1 is involved in the development of HIR injury by causing deterioration of the hepatic microcirculation. A nonselective ET receptor antagonist successfully ameliorated HIR injury through improvement of hepatic oxygenation and of the microcirculation along with reduced hepatic neutrophil infiltration.