Fig. 5.

Effect of normothermic machine perfusion on bioenergetic function. (a) Analysis of different respiratory coupling states: LEAK (L) respiration was reached after addition of succinate (10 mM) as substrate for the S-linked respiration and rotenone (0.5 μM) for Complex I inhibition in the absence of ADP. Then, ADP (5 mM) was added to analyse OXPHOS capacity (P) and subsequent addition of cytochrome c (10 μM) allowed to evaluate integrity of the mitochondrial outer membrane (P_c). Carbonyl cyanide p-trifluoromethoxyphenyl hydrazone (CCCP) was titrated step-wise until maximum respiration to assess the electron transfer (E) capacity. (b) For calculation of the P-L control efficiency, S-linked LEAK respiration served as background state and OXPHOS capacity served as reference state (1-L/P), which allows for evaluation of the efficiency of ATP production. (c) Cytochrome c control efficiency was calculated with OXPHOS capacity as background state and OXPHOS capacity upon addition of cytochrome c (P_c) as reference state (1-P/P_c), as a measure of mitochondrial outer membrane integrity. In the box plots, data are represented as median, interquartile range and min–max values while in the scatter plots single datapoints, median and interquartile range are shown. (b + c) Solid circles represent the transplanted, open boxes represent discarded livers. No significant differences within the coupling states or between the transplanted and discarded livers were found (p > 0.05, two-way ANOVA).