Background: Hypothermic machine perfusion is a well established method for deceased donor organ preservation as well as pre-transplant assessment and preconditioning. Recent translational and clinical studies have shown that normothermic perfusion offers similar and, perhaps, greater advantages. However, there does not exist sufficient data on a direct comparison of the two methods. Therefore, the aim of this study was to compare the two methods in an ex-vivo model using porcine kidneys.

Methods: 14 porcine kidneys from 7 donor pigs were retrieved in an abattoir after 25 minutes of warm ischaemia time and stored on ice for 24 hours. They were then either perfused hypothermically (4[deg]C, n=7) or normothermically (37[deg]C, n=7) for 4 hours using an RM3 pulsatile perfusion machine. Both kidneys were then reperfused with whole blood for 2 hours at 37[deg]C and physiological parameters, including the resistance index, perfusate flow rate, urinary output and oxygen consumption rate, were compared. The effects at a cellular level were assessed by measuring mRNA expressions of the inflammatory markers TNFα, IL-1β, NGAL and EDN-1 using RT-PCR. Statistical analysis was performed using ANOVA.

Results: Hypothermically perfused kidneys showed significantly higher urinary output rates (3.7ml/min ± 1.5ml/min vs. 1.6ml/min ± 0.9ml/min, p=0.022) as well as oxygen consumption rates (p=0.027) and perfusate flow rates (p=0.0013) at reperfusion than normothermically perfused kidneys. Interestingly, at mRNA level, expressions of proinflammatory markers were higher for hypothermically perfused kidneys, which reached significance for the expression of EDN-1 (12,37 ± 7,44 vs 3,03 ± 1,96, p=0,02), compared to the housekeeping gene.

Conclusion: We found that in a direct comparison to normothermic machine perfusion, hypothermic machine perfusion of porcine kidneys resulted in significantly improved physiological parameters and led to significantly increased urinary output rate despite showing a higher upregulation of inflammatory markers at mRNA level. Further investigations of the physiological and immunological parameters of both preservation methods are needed to optimise outcomes.

CITATION INFORMATION: Vallant N, Sandhu B, Wolfhagen N, Pusey C, Papalois V. Direct Comparison of Hypothermic and Normothermic Organ Preservation in a Porcine Ex-Vivo Kidney Model. Am J Transplant. 2017;17 (suppl 3).

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