Prevention of proteolysis in cold-stored rat liver by addition of amino acids to the preservation solution

Background: One process identified as detrimental in liver preservation is proteolysis. Methods: We tested the effects of adding antiproteolytic amino acids (L-alanine, L-glutamine, L-histidine, L-leucine, L-methionine, L-phenylalanine, L-proline, L-tryptophan) to the preservation medium, in a model of reperfusion of 24 h cold-stored rat livers. Results: During the preservation period, antiproteolytic amino acids inhibited the proteolysis observed in stored livers as shown by branched-chain amino acid fluxes, which switched from release to uptake. During reperfusion, cold storage of lives without the addition of antiproteolytic amino acids resulted in a decrease in the total amino acid and branched-chain amino acid uptake and a lower perfusion flow rate. The addition of antiproteolytic amino acids during liver storage resulted in the maintenance of total amino acid and branched-chain amino acid uptake and a significant improvement in the perfusion flow rate during reperfusion. Conclusions: The presence of antiproteolytic amino acids in the preservation medium might be of interest in improving hepatic graft viability in transplantation. (C) 2000 Blackwell Science Asia Pty Ltd.