Impact of rewarming preservation by continuous machine perfusion: improved post-transplant recovery in pigs

Utilization of grafts from donors after cardiac death (DCD) greatly expands the organ pool. However, implementation of such a strategy requires the development of novel preservation methods to achieve recovery from changes owing to warm ischemia.

To assess potential methods, porcine livers harvested after 60 minutes of warm ischemic time (WIT) were perfused and preserved under the following conditions: Group 1 (n = 3), 2-hour simple cold storage and 2-hour machine perfusion (MP) at 8°C; group 2 (n = 3), 2 hours at 25°C and MP at 25°C and group 3 (n = 3), 2-hour simple cold storage and gradual rewarming to 25°C by MP. The preserved liver grafts were transplanted orthotopically into recipients.

The aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and hyaluronic acid (HA) levels in recipient blood at 2 hours after reperfusion were significantly lower among group 3: AST, 789 ± 258.8, 1203 ± 217.0, and 421 ± 55.8 IU/L; LDH, 1417 ± 671.2, 2132 ± 483.9, and 634 ± 263.9 IU/L; and HA, 1660 ± 556.5, 1463 ± 332.3, and 575 ± 239.0 ng/mL for groups 1, 2 and 3, respectively. Histologically, necrosis and swelling of hepatocytes were less severe among group 3 than groups 1 and 2. Group 3 animals showed better vital responses and started spontaneous breathing within 2 hours after reperfusion; 1 recipient survived for >24 hours, although all animals in groups 1 and 2 died within 2 to 3 hours after reperfusion.

Rewarming by MP preservation may facilitate recovery and resuscitation of DCD liver grafts.