Ketone Body Supplementation Exerts Renoprotective Effects Against Adenine‐Induced Kidney Injury via <scp>OXCT1</scp> ‐Mediated Ketolysis in Mice

Ketone bodies have traditionally been recognized as glucose-sparing energy sources, with hepatic ketogenesis and peripheral ketolysis serving pivotal functions in maintaining energy homeostasis during fasting. Although they are commonly seen as harmful due to their link with ketoacidosis, recent studies emphasize their roles in organ protection. This has sparked interest in their possible use as a treatment for chronic kidney disease (CKD). In this study, we examined both exogenous and endogenous ketone body supplementation in adenine-induced kidney injury in mice. Supplementation with the ketone body precursor 1,3-butanediol significantly improved adenine-induced renal fibrosis, inflammation, and apoptotic cell death. However, genetically deleting 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), the key enzyme for ketogenesis, in the liver, kidney, or entire body, and removing Succinyl-CoA:3-ketoacid-CoA Transferase 1 (OXCT1), the enzyme for ketolysis, in the kidney alone, did not affect the severity of adenine-induced kidney damage. In contrast, the protective effects of 1,3-butanediol were partially diminished in mice with kidney-specific OXCT1 deficiency, indicating that OXCT1-mediated ketolysis is at least partly necessary for the renal protection afforded by exogenous ketone body supplementation. These findings suggest that supplementing with exogenous ketone bodies, rather than relying on endogenous hepatic or renal ketone production, protects the kidneys in adenine-induced kidney injury in mice, implying that local ketolysis within the kidney plays a mechanistic role in this protection. Our results highlight the therapeutic potential of exogenous ketone body administration in CKD and offer insights into how renal ketone metabolism helps protect against kidney injury.