Background: Machine perfusion (MP) has been implemented either under hypothermic and anoxic conditions or under normothermia with full oxygenation using blood as perfusate. This is the first pre-clinical large animal series using MP under subnormothermic conditions with a new hemoglobin-based oxygen carrier solution in a dual pressure system for liver preservation. Methods: Two groups of 6 Landrace pigs underwent orthotopic liver transplantation after CIT=9 hours where cold static preservation (CSP) was compared to MP. The MP allografts were continuously perfused by pulsatile and continuous pressures under full oxygenation at 21°C. Both groups had extensive graft and perfusate analysis during the preservation time. The MP group had continuous gasometry of the perfusate and tissue oximetry analysis. Mitochondrial function was analyzed in both groups. All tissues were blindly analyzed through standard histology, immunohistochemistry and electronic microscopy. Results: The CSP group had a significantly higher mortality (67% vs 0, p<0.05) and graft dysfunction when compared to the MP group. There were significant (p<0.05) differences between the 2 groups when more than 17 parameters were analyzed. The MP animals experienced none to mild I/R injuries and showed signs of early recovery at the 5^th post-operative day. Liver allografts made bile and cleared lactate while under MP. Tissue oximetry revealed pO₂>200 mmHg while under MP. Mitochondrial function over the MP period showed sustained respiratory control ratio, reliable ATP production and a mild generation of reactive oxygen species after graft reperfusion.Conclusions: MP at 21°C with a new HBOC solution provides effective oxygenation to liver allografts over an extended period of time. MP with full oxygenation decreases the magnitude of I/R injuries and carries no short-term morbidities and/or mortality to porcine transplant recipients.

van der Plaats, A.: Employee, Organ Assist. Light, W.: Employee, OPK Biotech.

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