Normothermic acellular ex vivo liver perfusion reduces liver and bile duct injury of pig livers retrieved after cardiac death.

We compared cold static with acellular normothermic ex vivo liver perfusion (NEVLP) as a novel preservation technique in a pig model of DCD liver injury. DCD livers (60 min warm ischemia) were cold stored for 4 h, or treated with 4 h cold storage plus 8 h NEVLP. First, the livers were reperfused with diluted blood as a model of transplantation. Liver injury was determined by ALT, oxygen extraction, histology, bile content analysis and hepatic artery (HA) angiography. Second, AST levels and bile production were assessed after DCD liver transplantation. Cold stored versus NEVLP grafts had higher ALT levels (350 ± 125 vs. 55 ± 35 U/L; p < 0.0001), decreased oxygen extraction (250 ± 65 mmHg vs. 410 ± 58 mmHg, p < 0.01) and increased hepatocyte necrosis (45% vs. 10%, p = 0.01). Levels of bilirubin, phospholipids and bile salts were fivefold decreased, while LDH was sixfold higher in cold stored versus NEVLP grafts. HA perfusion was decreased (twofold), and bile duct necrosis was increased (100% vs. 5%, p < 0.0001) in cold stored versus NEVLP livers. Following transplantation, mean serum AST level was higher in the cold stored versus NEVLP group (1809 ± 205 U/L vs. 524 ± 187 U/L, p < 0.05), with similar bile production (2.5 ± 1.2 cc/h vs. 2.8 ± 1.4 cc/h; p = 0.2). NEVLP improved HA perfusion and decreased markers of liver duct injury in DCD grafts.

Relaxin as a protective substance in preservation solutions for organ transplantation, as shown in an isolated perfused rat liver model.

Reperfusion injury, a well-known problem in organ transplantation, results from multiple pathologic mechanisms, including platelet/mast cell activation and peroxidation of cell membrane lipids. Relaxin was originally described as an insulin-like hormone produced in the ovaries during pregnancy. It causes vessel dilation and inhibition of platelet and mast cell activation. The present study investigated the protective effect of relaxin against reperfusion injury in liver tissue. We used a model of isolated perfused rat liver to simulate liver transplantation. Organ preservation was performed identical to human transplantation in 20 male Wistar rats. During preservation we applied 64 ng/mL relaxin. In contrast controls (n = 10) had no relaxin treatment. To quantify cell damage, we measured malonyldialdehyde (MDA; end product of lipid peroxidation) and myeloperoxidase activity (MPO; marker for accumulation of neutrophil granulocytes) in the perfusates. The livers were examined immunohistochemically for the same parameters. Relaxin as an additional substance in preservation solutions decreased perfusate MPO and MDA levels by up to 30%, as shown by immunohistochemistry. Our preliminary data suggested that relaxin is a promising agent to reduce hepatocyte damage caused by ischemia-reperfusion injury. Quantitative analysis of MDA and MPO levels in the perfusate is the subject of an ongoing study.