The Role of L-Carnitine in Kidney Disease and Related Metabolic Dysfunctions

Kidney disease is associated with a wide variety of metabolic abnormalities that accompany the uremic state and the state of dialysis dependence. These include altered L-carnitine homeostasis, mitochondrial dysfunctions, and abnormalities in fatty acid metabolism. L-carnitine is essential for fatty acid metabolism and proper mitochondrial function. Deficiency in kidney disease and dialysis is caused by a reduction in endogenous renal synthesis, impaired fatty acid metabolism, a lower intake due to dietary restrictions, and nonselective clearance by the dialysis procedure. Free carnitine levels <40 µmol/L in dialysis patients can lead to dialysis-related complications, such as anemia that is hyporesponsive to erythropoietin therapy, intradialytic hypotension, cardiovascular disease, and skeletal muscle dysfunction manifested as muscle weakness and fatigue. L-carnitine deficiency is also seen in acute kidney injury (AKI) resulting from trauma and/or ischemia, drugs such as cisplatin, and from infections such as covid. A persistent state of L-carnitine deficiency can further damage kidneys and lead to multi-organ failure. Carnitine supplementation has been shown to be safe and effective in improving kidney disease-related complications resulting from drug-induced toxicity, trauma, ischemic injury, infection, and dialysis, by replenishing adequate carnitine levels and rebalancing carnitine homeostasis. In this review, we will examine the protective role of L-carnitine in reducing cellular oxidative damage and maintaining mitochondrial function together with the clinical evidence for its potential use in the management of kidney disease.