Advancing small-animal perfusion models: Normothermic dual-vessel ex vivo rat liver machine perfusion based on a clinical setup

Abstract

Normothermic ex vivo liver machine perfusion (NEVLP) has been developed to address organ shortage in liver transplantation. To establish new therapeutic concepts for the expansion of the donor pool, standardized animal models are needed, that simulate clinical NEVLP. Rat liver grafts were perfused in a dual-vessel NEVLP system using varying doses of the clinically used vasodilator epoprostenol, with and without the addition of the Kupffer cell inhibitor glycine. Cell culture medium supplemented with rat plasma was compared to SteenTM-based perfusion solution, which is used in clinical NEVLP. Perfusion pressures and bile production were recorded, perfusate transaminases levels were measured and tissue was analyzed for cytokines and 8-Isoprostane. Increasing levels of epoprostenol and the addition of glycine resulted in a stepwise decrease of transaminase secretion and improved bile production. SteenTM significantly decreased transaminase secretion as well as IL-1β production, resulting in lowest levels of oxidative stress and best-preserved liver integrity. In conclusion, high doses of epoprostenol seem to ameliorate liver function and prevent cellular damage, with glycine acting synergistically. SteenTM as perfusion basis seems superior. Our rodent NEVLP system may be used to rapidly test new agents for pharmacologic conditioning of livers and to translate these findings from bench-to-bedside.