Procurement and Ex-Situ Perfusion of Isolated Slaughterhouse-Derived Livers as a Model of Donors after Circulatory Death.

Ex-situ machine perfusion (MP) techniques are increasingly used in clinical settings, especially on grafts from donors after cardiac death (DCD). However, the biological effects elicited by machine perfusion are largely unknown, and a substantial number of animal studies are presently focused on this topic. The aim of the present study was to describe a model of DCD based on ex-situ perfusion of liver grafts derived from animals used for food production. Procurement took place within a slaughterhouse facility. After cold storage, the liver grafts were perfused with autologous blood-enriched perfusion fluid in a clinically fashioned closed circuit normothermic MP (NMP). During the rewarming phase, temperature and flows were progressively increased to reach target values. Perfusate and tissue samples were collected to assess NMP functionality. Grafts were classified as transplantable (LT-G) or not (nLT-G) according to clinical criteria, and viability was confirmed by histopathological analysis. Four grafts were classified as LT-G and three as nLT-G at the end of NMP. Histology confirmed the absence of major damage in LT-G, while nLT-G presented diffuse necrosis. Interestingly, an early impairment of the hepatocyte respiratory chain, leading to cell necrosis and graft non-viability, was documented in nLT-G for the first time. These parameters, together with indocyanine-green dye and citrate clearance could contribute to graft evaluation in clinical settings. The model provides a promising and reproducible method to replace dedicated experimental animals in research on machine perfusion of DCD grafts in line with the 3Rs principles. [ABSTRACT FROM AUTHOR]