Hypothermic oxygenated machine perfusion enables 24-hour ex situ preservation of porcine donation after circulatory death livers

I.M.A. Brüggenwirth, O.B. van Leeuwen, Y. de Vries, J. Adelmeijer, J.J. Wiersema-Buist, T. Lisman, P.N. Martins, R.J. Porte

Wednesday 13 march 2019

14:28 - 14:30h at Koningin Máximazaal

Categories: Basaal, Parallelsessie

Parallel session: Parallelsessie III - Basaal I

Background: End-ischemic hypothermic oxygenated machine perfusion reduces ischemia-reperfusion injury of donor liver grafts during storage and subsequent transplantation. However, it is unknown whether this technique also supports an extension of the ex situpreservation time. We aimed to determine whether liver grafts from donation after circulatory death (DCD) porcine donors can be effectively preserved for up to 24-hours using dual hypothermic oxygenated machine perfusion (DHOPE).

Methods: Liver grafts from DCD pig donors were subjected to 2h static cold storage (SCS), followed by 2, 6, or 24 hours DHOPE (n=6 in each group), using Belzer UW machine perfusion solution. Subsequently, hepatocellular and bile duct viability were tested during 4h normothermic ex situreperfusion with autologous whole blood. DCD livers preserved for 24h by SCS (n=2) served as controls.

Results: In all three study groups, portal venous and arterial flows remained stable during DHOPE. After normothermic graft reperfusion, there were no significant differences in lactate clearance, blood pH, glucose and alanine aminotransferase levels among the three groups of DHOPE-preserved livers. All livers produced bile and there were no significant differences in biliary HCO₃^-, pH, and LDH between the three DHOPE groups at 4h after reperfusion. Moreover, levels of malondialdehyde (marker for oxidative stress) and danger associated molecular pattern protein HMGB-1 in serum and liver parenchyma, were similar for all three groups of DHOPE-preserved livers. Levels of cell-free DNA, a marker of cell death, were not different between the thee groups. Histological analyses of bile ducts and liver parenchyma also revealed no differences. In contrast, livers preserved for 24h ex situby SCS did not produce any bile after reperfusion and turned bluish with reducing portal and arterial flows, representative for a dying/non-functional liver. Histology of these livers revealed massive cellular necrosis.

Conclusions: While 24h SCS preservation of porcine DCD liver grafts leads to massive necrosis and primary non-function after warm reperfusion, DHOPE enabled successful ex situpreservation of donor livers for up to 24h. If confirmed with human liver grafts, this technique opens new avenues to prolong storage time in case of necessity (e.g. difficult recipient hepatectomy) or to allocate grafts over longer distances.