Air‐ventilated normothermic mechanical perfusion improves susceptibility to donation after circulatory death and cold preservation‐induced cholestatic liver injury through PPAR‐γ/UGT1A1 axis

Abstract

AbstractEnd‐ischemic normothermic mechanical perfusion (NMP) could provide a curative treatment to reduce cholestatic liver injury from donation after circulatory death (DCD) in donors. However, the underlying mechanism remains elusive. Our previous study demonstrated that air‐ventilated NMP could improve functional recovery of DCD in a preclinical NMP rat model. Here, metabolomics analysis revealed that air‐ventilated NMP alleviated DCD‐ and cold preservation‐induced cholestatic liver injury, as shown by the elevated release of alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin, and γ‐glutamyl transferase (GGT) in the perfusate (p < .05) and the reduction in the levels of bile acid metabolites, including ω‐muricholic acid, glycohyodeoxycholic acid, glycocholic acid, and glycochenodeoxycholate (GCDC) in the perfused livers (p < .05). In addition, the expression of the key bile acid metabolism enzyme UDP‐glucuronosyltransferase 1A1 (UGT1A1), which is predominantly expressed in hepatocytes, was substantially elevated in the DCD rat liver, followed by air‐ventilated NMP (p < .05), and in vitro, this increase was induced by decreased GCDC and hypoxia‐reoxygenation in the hepatic cells HepG2 and L02 (p < .05). Knockdown of UGT1A1 in hepatic cells by siRNA aggravated hepatic injury caused by GCDC and hypoxia‐reoxygenation, as indicated by the ALT and AST levels in the supernatant. Mechanistically, UGT1A1 is transcriptionally regulated by peroxisome proliferator‐activator receptor‐γ (PPAR‐γ) under hypoxia–physoxia. Taken together, our data revealed that air‐ventilated NMP could alleviate DCD‐ and cold preservation‐induced cholestatic liver injury through PPAR‐γ/UGT1A1 axis. Based on the results from this study, air‐ventilated NMP confers a promising approach for predicting and alleviating cholestatic liver injury through PPAR‐γ/UGT1A1 axis.