Renalase as a Novel Biomarker for Evaluating the Severity of Hepatic Ischemia-Reperfusion Injury

Hepatic ischemia-reperfusion (I/R) injury is a serious complication in clinical practice. However, no efficient biomarkers are available for the evaluation of the severity of I/R injury. Recently, renalase has been reported to be implicated in the I/R injury of various organs. This protein is secreted into the blood in response to increased oxidative stress. To investigate the responsiveness of renalase to oxidative stress, we examined the changes of renalase in cell and mouse models. We observed a significant increase of renalase expression in HepG2 cells in a time- and dose-dependent manner when treated with H(2)O(2). Renalase expression also increased significantly in liver tissues that underwent the hepatic I/R process. The increased renalase levels could be efficiently suppressed by antioxidants in vitro and in vivo. Furthermore, serum renalase levels were significantly increased in the mouse models and also efficiently suppressed by antioxidants treatment. The variation trends are consistent between renalase and liver enzymes in the mouse models. In conclusion, renalase is highly sensitive and responsive to oxidative stress in vitro and in vivo. Moreover, renalase can be detected in the blood. These properties make renalase a highly promising biomarker for the evaluation of the severity of hepatic I/R injury.