Bile analysis as a tool for assessing integrity of biliary epithelial cells after cold ischemia-reperfusion of rat livers

Previous morphological studies failed to show appreciable injury of biliary epithelial cells (BEC) after cold ischemia of rat liver, although recent e vidence indicated that BEC integrity and function were impaired in this mod el. We tested the hypothesis that analysis of bile for enzymes, such as lac tate dehydrogenase (LDH), alanine transaminase (ALT), and aspartate transam inase (AST), can be used for assessing cold ischemic injury of BEG. Further more, we examined whether biliary gamma -glutamyltransferase (GGT) reflects warm ischemic injury of BEC and whether normothermic reperfusion aggravate s the negative effect of cold ischemia on BEC integrity and function. Rat l ivers were reperfused after different periods of cold or warm ischemia usin g a blood-free perfusion model. Compared with controls, perfusate LDH, ALT, and AST levels and parameters of hepatocyte function, including hepatocyte tight junction permeability, were not significantly altered by 18-h cold i schemia. On the other hand, 9-h cold ischemia markedly increased biliary LD H, ALT, and AST levels. However, only LDH release into the bile was strongl y dependent on the time of cold storage. Biliary GGT, LDH, and glucose leve ls decreased during the reperfusion period following 18-h cold ischemia. Th e results suggest that biliary LDH can be used for assessing injury of BEC in cold-preserved livers and that normothermic reperfusion does not aggrava te preservation-induced injury of BEC after cold ischemic storage, (C) 2000 Academic Press.