The effect of consecutively larger doses of L-arginine on hepatic microcirculation and tissue oxygenation in hepatic steatosis

Background: Impairment of hepatic microcirculation in fatty liver is thought to render it more susceptible to the effects of ischaemia-reperfusion injury as compared to non-fatty liver grafts. The present study aimed to investigate the effect of consecutively larger doses of L-arginine on the hepatic microcirculation and tissue oxygenation of fatty liver. Methods: Sprague-Dawley rats (200-250 g) were fed a liquid ethanol diet to induce hepatic steatosis or a normal diet for 6 weeks. Hepatic blood flow, microcirculation, tissue oxyhaemoglobin (HBO2) in response to consecutive intravenous bolus administrations of L-arginine (50 mg/kg, 100 mg/kg, 300 mg/kg and 500 mg/kg) or normal saline, were assessed. Results: Baseline hepatic arterial flows and hepatic microcirculation values were significantly lower in steatotic livers vs. control livers. L-arginine significantly improved hepatic arterial, portal venous blood flow, hepatic microcirculation and tissue oxygenation in both fatty and control livers. Conclusions: The administration of NO in cumulatively larger doses is effective at improving hepatic blood flow, microcirculation and hepatic tissue oxygenation in steatotic liver and these results could form the basis of further work into using NO as a therapeutic tool to reclaim moderately steatotic grafts for use in liver transplantation. (C) 2009 Elsevier Inc. All rights reserved.