SUBNORMOTHERMIC MACHINE PERFUSION REDUCES PRESERVATION DAMAGE OF LIVERS FROM NON-HEART BEATING DONORS: A NEW CHANCE FOR EXPANDING THE DONOR POOL?

Background and aim: Machine perfusion (MP) preservation may enhance donor pool by reclaiming marginal livers including organs from non–heart-beating donors (NHBDs). We recently reported that MP performed at 20°C greatly enhanced the rat liver preservation of steatotic livers (1). Here, we tested whether the organ preservation by MP at 20°C can also enhance the functional integrity of rat livers obtained from NHBDs when compared with cold storage. To further support our hypothesis we also compared MP at 20°C with hypothermic MP at 4°C. Materials and methods: 11-12 week old male Wistar rats were used as liver donor. MP technique: livers were perfused for 6 hrs with UW-G modified pH 7.4 at 20°C and 4°C. Cold storage: livers were perfused in situ and preserved with UW solution at 4°C for 6 hrs. Both MP and cold storage preserved livers were reperfused with Krebs-Heinselet buffer (2-hrs at 37°C). Aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) release and glutamate dehydrogenase (GDH) levels (index of mitochondria dysfunction) were evaluated. Parameters under evaluation were also bile production and oxygen consumption. Results: Livers preserved by MP at 20°C show a significant lower hepatic damage at the end of reperfusion period as compared with MP at 4°C and cold storage (LDH mU/min/g: 12.9±1.1 versus 23.7±4.6 and 22.1±1.9, p<0.05). Release of GDH was significantly reduced and bile production was higher in livers preserved by MP at 20°C compared with MP at 4°C and cold storage (GDH mU/min/g: 4.1±0.6 versus 8.5±1.1 and 6.5±0.6, p<0.05; Bile ml/g: 51±6 versus 21±7 and 37±6, p<0.05). No significant difference in oxygen up-take was found. Conclusions: MP at 20°C, improving cell survival, results in a better-quality preservation of livers obtained from NHBDs as compared with MP at 4°C and conventional cold storage. MP under a moderate hypothermia might provide a new method for a successful utilization of marginal livers such as those obtained from NHBDs.