Use of a New Modified HTK Solution for Machine Preservation of Marginal Liver Grafts

Background The present study was undertaken to investigate the putative benefit of a new, modified HTK solution for hypothermic machine perfusion using a model of rat livers from non-heart beating donors. Methods Livers were retrieved 30 min after cardiac arrest of male Wistar rats and put on a recirculating machine perfusion device. Hypothermic machine perfusion (HMP) was performed for 18 h at 4°C and a rate of 0.5 mL/g−1 min−1 while the preservation solution was oxygenated with 100% O2. Each liver was randomly assigned to the use of one of the following preservation solutions: HTK (histidine-tryptophan-ketoglutarate solution); Custodiol-N base solution (modified HTK-solution) without additives or with the addition of 25 μM deferoxamine + 2.5 μM (Custodiol-N, 2.5) or 7.5 μM (Custodiol-N) of the permeable iron chelator LK 614. Viability of livers was evaluated upon reperfusion in vitro with Krebs-Henseleit buffer according to previously validated techniques for 120 min at 37°C. Results The use of Custodiol-N base solution led to a significantly decreased release of ALT or LDH during HMP and after reperfusion, which was further reduced by Custodiol-N and minimal use of Custodiol-N, 2.5. Only the use of Custodiol-N, 2.5 resulted in an improvement of metabolic activity upon reperfusion, as evaluated by hepatic production of C02, significantly reduced cleavage of caspase 9, and abrogated positive signs of cellular of apoptosis [terminal deoxynucleotide transferase-mediated deoxy-UTP nick-end labeling (TUNEL)-test)]. Conclusion The data presented provide first experimental evidence for enhanced organ protective potential of the new Custodiol-N solution compared with HTK upon hypothemic machine preservation of marginal liver grafts. Moreover, for continuous perfusion preservation the dosage of the lipophilic chelator LK 614 should probably be lower than for static cold storage.