Long-term ex-vivo normothermic perfusion of human split livers: a unique model to study new therapeutics and increase the number of available organs

Abstract Current perfusion technology only allows livers to be preserved ex-vivo for short periods. Long-term normothermic perfusion of livers is an emerging field with tremendous potential for the assessment, recovery, and modification of organs. In this study, we aimed develop a long-term model of ex-vivo perfusion including a surgical split and simultaneous perfusion of both partial grafts. Our long-term perfusion system included long-term oxygenators, a gas-mixer and a dialysis filter. Human livers declined for transplantation were perfused using a red-cell based perfusate under normothermic conditions (36°C) and then split and simultaneously perfused on separate machines. Ten human livers were split resulting in 20 partial grafts. The median ex-vivo survival was 165 hours (7 days). Long-term graft survival was demonstrated by lactate clearance, bile production, Factor-V production, and storage of adenosine triphosphate. The grafts that survived > 7 days demonstrated significantly higher bile production, Factor-V production, and hepatic arterial flow and significantly lower microvesicular steatosis. We report reliable long-term ex-vivo perfusion of human livers and demonstrate the ability to split and perfuse these organs using a reproducible protocol. This provides the opportunity for improved assessment of organs and could act as a model for the testing of therapeutics with a matched control.