Background: Endothelin (ET)-1 contributes to hepatic ischemia and reperfusion (HIR) injury in normal liver. This study was conducted to clarify the role of ET-1 in HIR injury in cirrhotic state.
Materials and methods: Using thioacetamide-induced cirrhotic rats with spontaneous portosystemic shunt, we determined the changes in plasma aspartate aminotransferase (AST) levels, plasma and hepatic ET-1 values, 7-day survival rates, and hepatic oxygen saturation (SO(2)) by time-resolved spectroscopy as an indicator of hepatic microcirculation under intermittent or continuous total hepatic ischemia with subsequent partial hepatectomy.
Results: Hepatic ET-1 levels in cirrhotic rats were significantly higher than those in noncirrhotic rats. Plasma and hepatic ET-1 levels at 1, 3 and 6 h of reperfusion after intermittent hepatic ischemia were significantly lower than those after continuous hepatic ischemia. In cirrhotic animals subjected to intermittent hepatic ischemia, the elevation of plasma AST levels at 1, 3 and 6 h of reperfusion and the decline in hepatic SO(2) at the end of 60-min hepatic ischemia and after reperfusion were significantly suppressed when compared with those subjected to continuous hepatic ischemia. Pretreatment with a nonselective endothelin receptor antagonist in continuous hepatic ischemia significantly ameliorated plasma AST levels and hepatic SO(2) values with less hepatic sinusoidal congestion, resulting in an improvement in the 7-day survival rate.
Conclusions: Continuous hepatic ischemia in the cirrhotic liver has disadvantages relating to microcirculatory derangement with more ET-1 production in partial hepatectomy. In liver surgery, pharmacological regulation of ET-1 production may lead to attenuation of reperfusion injuries for ischemically damaged cirrhotic liver.