Effects of hypothermic machine perfusion on rat liver function depending on the route of perfusion

Background and Methods. The aim of this study was to evaluate the efficacy of hypothermic machine perfusion (HMP) to preserve rat livers according to the route of perfusion, i.e., via portal vein, hepatic veins (retrograde), or hepatic artery. Livers were preserved for 24 or 48 hr by simple cold storage (SCS) or by EMP. Preservation solution was supplemented with (HMP) or without (SCS) hydroxyethyl starch. After preservation, grafts were reperfused for 2 br with an oxygenated Krebs-Henseleit bicarbonate buffer. Results. After 24 hr of preservation, total glutathione concentrations in EMP livers were similar (1287 +/- 37, 1418 +/- 118, and 1471 +/- 62 nmol/g in hepatic artery, portal vein, and hepatic vein HMP livers, respectively) and higher than in the SCS (833 +/- 118 nmol/g, P <0.05) group. These higher total glutathione values were due to higher reduced glutathione concentrations. ATP concentrations in the liver tissue were similar in HMP groups (0.75 +/-0.4, 0.64 +/-0.1, and 0.77 +/-0.1 mu mol/g in hepatic artery, portal vein, and hepatic vein HMP livers, respectively) and higher than in SCS (0.32 +/-0.06 mu mol/g, P <0.05). After 2 hr of normothermic reperfusion, bile production in the HMP portal and HMP retrograde groups were similar (391 +/- 29 ml and 372 +/- 25 ml) and higher than in the HMP artery or SCS groups (275 +/- 25 ml and 277 +/- 32 ml, respectively; P <0.05). Aspartate transaminase, alanine transaminase, lactate dehydrogenase, and purine nucleoside phosphorylase release into the perfusate of HMP portal and HMP retrograde perfused livers was similar and significantly lower compared to the EMP artery and SCS groups. At the end of reperfusion, no statistical differences were found for glutathione concentration and energetic reserves in the livers of each group. After 48 hr of preservation, livers from the HMP portal and EMP retrograde groups did significantly better than livers from the HMP artery or SCS groups. Conclusions. This study confirms the superiority of HMP over SCS to preserve the liver graft. It shows that retrograde perfusion is similar to PV perfusion and that perfusion by HA is less beneficial.