Abstract
Cultured kidney cells maintained in conventional growth media with high glucose levels exhibit increased glycolytic activity compared to the cells in vivo. In contrast, renal proximal tubules utilize substrates such as ketone bodies and rely on mitochondrial oxidative phosphorylation. LLC-PK1 cells maintain many features of the proximal tubule but are exposed to glucose concentrations ranging from 17 to 25 mM. This may impact their reliability in predicting mitochondrial toxicity. This study is designed to test the impact of the ketone body acetoacetate on metabolic characteristics of LLC-PK1 cells. Basal respiration, maximal respiration, spare respiratory capacity and ATP-linked respiration were significantly increased in cells grown in growth medium supplemented with 5 mM acetoacetate. In contrast, glycolytic capacity, as well as glycolytic reserve were significantly reduced in the acetoacetate group. There was an increased expression in biomarkers of mitochondrial biogenesis, and an increase in mitochondrial protein expression. Cells grown in medium complemented with acetoacetate displayed a significantly lower LC50 when treated with clotrimazole and diclofenac. There was a marked increase in uncoupled respiration in the presence of diclofenac, while clotrimazole and ciprofibrate significantly decreased respiration in the acetoacetate. The results indicate that acetoacetate complemented media can alter cellular metabolism and increase sensitization to toxicants.