Six-hour local 4 °C dual hypothermic oxygenated machine perfusion improves the preservation of porcine liver after cardiac death using an ex vivo reperfusion model.

Abstract

Background: The use of grafts from donation after circulatory death (DCD) overcomes the inadequate donor organ supply. Our team developed a transportable dual hypothermic oxygenated machine perfusion (DHOPE) device, which initiates DHOPE at a recipient center to reduce static cold storage (SCS) time and the risk of graft failure in DCD liver transplantation.

Methods: Six porcine livers per group with 30 min of warm ischemia exposure were preserved via SCS or DHOPE for 6 h and then reperfused for 12 h with whole blood to mimic transplantation. Hepatocellular and biliary function and injury were assessed in perfusate and bile samples. Molecular biomarkers and histology were compared between groups.

Results: Reperfusion portal vein pressure, in a flow-constant manner, and alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and gamma-glutamyltransferase (γ-GGT) release were significantly lower in the DHOPE group than in the SCS group at all time points. Higher bile production paralleled the lower levels of ALP and γ-GGT in the DHOPE group. The DHOPE group secreted more total bilirubin (TBIL) in bile, resulting in decreased TBIL in the perfusate, and livers preserved with DHOPE exhibited better cholangiocellular function. Furthermore, improvements in hypoxia, the inflammatory response, cell-free microRNAs and energy metabolism were observed in the DHOPE group. There were fewer apoptotic cells and TGF-β1-positive cells in the liver parenchyma and extrahepatic bile duct in the DHOPE group than in the SCS group.

Conclusions: This study demonstrates the efficacy of local 4 °C DHOPE to protect porcine liver grafts from 30-min warm ischemia damage.