Macronutrient Supplementation During Prolonged Normothermic Incubation Increases Mitochondrial Function of Precision-Cut Kidney Slices After Ischemia

Background/Objectives: Kidneys from marginal donors are more susceptible to ischemia–reperfusion injury (IRI). To diminish the deleterious effects of IRI, mitochondria should be preserved optimally between donation and transplantation. It is unknown which macronutrients are imperative to support mitochondrial function during normothermic preservation. The aim of this study is to investigate the effect of different macronutrient compositions on mitochondrial function during prolonged normothermic incubation of precision-cut kidney slices. Methods: Both porcine (n = 8) and human (n = 5) kidneys were studied. After warm ischemia and cold preservation, precision-cut kidney slices (PCKS) were made and incubated in different incubation media under normothermic conditions. PCKS were incubated with all different combinations of glucose, glutamine and/or fatty acids. At zero, 24 and 48 h, mitochondrial function and metabolite levels were assessed. Results: After 48 h of incubation, ATP levels were significantly higher with glucose and glutamine or fatty acids and glutamine, compared to incubation without nutrients (p = 0.001 and p = 0.003, respectively). Also, mitochondrial oxygen fluxes were higher with all nutrients compared to no nutrients (ADP stimulated basal respiration p = 0.040; proton leak p = 0.001 and maximal respiration p = 0.039). Conclusions: The addition of multiple macronutrients during prolonged normothermic incubation increases the mitochondrial function of PCKS. These data pave the way for optimising the nutritional support for ex vivo perfusion of marginal kidneys.