Hypothermic Machine Perfusion with Hydrogen Gas Reduces Focal Injury in Rat Livers but Fails to Restore Organ Function.

BACKGROUND

We have previously reported the efficacy of post-reperfusion H gas treatment in cold storage (CS) and subsequent reperfusion of the rat liver. The present study aimed to evaluate the effect of H gas treatment during hypothermic machine perfusion (HMP) in rat livers retrieved from donation after circulatory death (DCD) and elucidate the mechanism of action of H gas.

METHODS

Liver grafts were procured from rats after 30 min of cardiopulmonary arrest. The graft was subjected to HMP for 3 hours at 7°C using Belzer MPS with or without dissolved H gas. The graft was reperfused using an isolated perfused rat liver apparatus at 37°C for 90 minutes. Perfusion kinetics, liver damage, function, apoptosis, and ultrastructure were evaluated.

RESULTS

Portal venous resistance, bile production, and oxygen consumption rates were identical in the CS, MP, and MP-H groups. Liver enzyme leakage was suppressed by MP (vs control), whereas H treatment did not show a combination effect. Histopathology revealed poorly stained areas with a structural deformity just below the liver surface in the CS and MP groups, whereas these findings disappeared in the MP-H group. The apoptotic index in the CS and MP groups was high but decreased in the MP-H group. Mitochondrial cristae were damaged in the CS group but preserved in the MP and MP-H groups.

CONCLUSIONS

In conclusion, HMP and H gas treatment are partly effective in DCD rat livers but insufficient. Hypothermic machine perfusion can improve focal microcirculation and preserve mitochondrial ultrastructure.