Ischemic preconditioning protects the steatotic mouse liver against reperfusion injury: an ATP dependent mechanism

Background/Aims: Hepatic steatosis is a major risk factor for liver surgery and transplantation. The increased susceptibility of fatty livers to ischemic injury is associated with a necrotic form of cell death as opposed to apoptosis in lean animals, and is possibly related to low contents of ATP. Ischemic preconditioning, a brief period of ischemia prior to a prolonged period, protects the lean liver against ischemia through anti-apoptotic properties. We evaluated whether ischemic preconditioning also confers protection in the fatty liver and whether it protects against the ATP loss. Methods: The effect of ischemic preconditioning was tested in steatotic and lean livers subjected to 75 min of ischemia and 4 or 24 h of reperfusion. Tissue ATP contents were assessed at various times, and a model of low hepatic ATP contents (starvation) was studied to assess the type of injury following ischemia and the effects of preconditioning. Results: Ischemic preconditioning protected steatotic livers against massive necrosis. ATP levels were significantly higher before and after reperfusion in liver subjected to preconditioning when compared to controls. Liver with low baseline ATP levels (starvation) were also associated with necrosis, and were protected by ischemic preconditioning. Conclusions: Ischemic preconditioning mainly protects the fatty liver against necrosis possibly through preservation and restoration of tissue ATP contents. (C) 2003 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.