Influence of Flow and Addition of Oxygen During Porcine Liver Hypothermic Machine Perfusion

IntroductionIn contrast with kidneys, data on hypothermic machine perfusion (HMP) of livers remain scarce. Optimal liver HMP is poorly defined. Superiority of liver HMP over simple cold storage (SCS), the current standard preservation, must be proven before HMP is applied clinically. In this study, morphology and adenosine triphosphate (ATP) contents of HMP livers at different flows and with versus without O2 studied in a porcine ex vivo model were compared to SCS.MethodsPig livers were procured, flushed with HTK and preserved via SCS or HMP at 3 HMP settings: high flow (HF); low flow (LF); low flow + O2 (300 mm Hg) (LFO). HMP livers were perfused via the hepatic artery (HA) and portal vein (PV) with KPS-1 TM at 4°C to 6°C for 24 hours with HF: PV: 3 to 5 mm Hg, 1 mL/g liver/min for HA and 25 mm Hg; LF: PV: 3 to 5 mm Hg, 0.5 ml/g liver/min with HA: 20 mm Hg. Morphology and ATP levels were measured in preserved liver tissues.ResultsThroughout the SCS preservation, livers remained intact. In HMP livers, vacuoles appeared after 4 hours of preservation in the HF group and after 12 hours in the LF livers. LFO livers remained intact with limited vacuoles. Compared to SCS, HMP livers showed dilated sinusoids, particularly in the HF group. ATP remained relatively constant or even increased during HMP, particularly in the LF group, whereas ATP decreased after SCS.ConclusionAmong the various HMP settings, HMP with LFO was superior. ATP levels were the highest in LF. In contrast with all HMP groups, SCS showed the lowest ATP levels, indicating that HMP has the potential to better preserve energy stores.