The Novel N,N-bis-2-Hydroxyethyl-2-Aminoethanesulfonic Acid-Gluconate-Polyethylene Glycol-Hypothermic Machine Perfusion Solution Improves Static Cold Storage and Reduces Ischemia/Reperfusion Injury in Rat Liver Transplant.

Organ transplantation is the treatment of choice against terminal and irreversible organ failure. Optimal preservation of the graft is crucial to counteract cold ischemia effects. As we developed an N,N-bis-2-hydroxyethyl-2-aminoethanesulfonic acid-gluconate-polyethylene glycol (BGP)-based solution (hypothermic machine perfusion [HMP]), we aimed to analyze the use of this solution on static cold storage (SCS) of rat livers for transplantation as compared with the histidine tryptophan ketoglutarate (HTK) preservation solution. Livers procured from adult male Sprague Dawley rats were preserved with BGP-HMP or HTK solutions. Liver total water content and metabolites were measured during the SCS at 0°C for 24 hours. The function and viability of the preserved rat livers were first assessed ex vivo after rewarming (90 minutes at 37°C) and in vivo using the experimental model of reduced-size heterotopic liver transplantation. After SCS, the water and glycogen content in both groups remained unchanged as well as the tissue glutathione concentration. In the ex vivo studies, livers preserved with the BGP-HMP solution were hemodynamically more efficient and the O2 consumption rate was higher than in livers from the HTK group. Bile production and glycogen content after 90 minutes of normothermic reperfusion was diminished in both groups compared with the control group. Cellular integrity of the BGP-HMP group was better, and the histological damage was reversible. In the in vivo model, HTK-preserved livers showed a greater degree of histological injury and higher apoptosis compared with the BGP-HMP group. In conclusion, our results suggest a better role of the BGP-HMP solution compared with HTK in preventing ischemia/reperfusion injury in the rat liver model.

Hypothermic machine perfusion versus cold storage in the rescuing of livers from non-heart-beating donor rats.

The aim of this work was to compare the efficiency of cold storage (CS) and hypothermic machine perfusion (HMP) methods of preserving grafts excised from non-heart-beating donors that had suffered 45 minutes of warm ischemia. We developed a new solution for HMP to use in liver transplantation, based on BES, gluconate, and polyethylene glycol (BGP-HMP solution). After 24 h of HMP or CS, livers were reperfused at 37°C with Krebs-Henseleit solution with added dextran. For both procedures, portal pressure and flow were measured and the intrahepatic resistance (IR) was calculated. The pH oscillations and enzyme activities (LDH, AST, and ALT) were evaluated for the perfusion buffer during normothermic reperfusion. O2 consumption of the liver, glycogen production, and bile flow were also measured during the normothermic reperfusion period. Portal flow and IR showed statistical differences (P < 0.05) between the two groups (n = 5). HMP with BGP-HMP solution resulted in higher values of portal flow and lower IR than CS with HTK solution. Enzyme release after 90 min of reperfusion did not show statistical differences between groups. With regard to bile flow and O2 consumption, livers preserved by both processes were able to produce bile, but livers preserved with HMP were able to take up more O2 than livers preserved by CS.