EVIDENCE FOR THE DETRIMENTAL ROLE OF PROTEOLYSIS DURING LIVER PRESERVATION IN HUMANS

Background/Aims: Proteolysis may persist in the liver allograft during cold storage. The aim of this study was to determine the significance of proteolysis within liver allografts stored at 4 degrees C in University of Wisconsin preservation fluid. Methods: Thirty recipients of 32 liver allografts were studied prospectively. Amino acid content of the preservation fluid was analyzed at the end of cold storage and was correlated to graft and patient outcome after transplantation. Results: Analysis of the preservation fluid showed the presence of free amino acids, the profile of which was different from that of stored liver parenchyma. Concentrations of amino acids (alanine, cysteine, leucine, isoleucine, methionine, lysine, ornithine, and threonine) and transaminases (alanine aminotransferase and aspartate aminotransferase) in the preservation fluid correlated with the duration of cold ischemia. Indexes of graft dysfunction (serum alanine aminotransferase and aspartate aminotransferase peaks and prothrombin rate) correlated with concentrations of cysteine, alanine, isoleucine, leucine, methionine, lysine, ornithine, and threonine, whereas enzyme concentrations in the fluid were not predictive of graft dysfunction. Conclusions: These data suggest that liver proteolysis occurs during cold storage and may have a detrimental effect on the outcome after transplantation. The measurement of the amino acids in the preservation fluid at the end of the cold storage period could help to identify the most severely damaged organs.