Background: Depression is highly prevalent in uremic patients undergoing hemodialysis
(HD). We previously found that low free-carnitine levels are associated with depression severity in
male patients undergoing HD. However, whether L-carnitine supplementation improves the
depression state in male patients undergoing HD remains unclear.
Methods: Sixteen male patients undergoing HD were orally administered 900 mg L-carnitine daily or
intravenously administered 1000 mg L-carnitine immediately after undergoing HD for 3 months. The
depression state and various types of carnitine levels were evaluated using the self-rating depression
scale (SDS) and tandem mass spectrometry, respectively, at baseline and 3 months after treatment.
Results: L-carnitine supplementation significantly increased serum levels of free and other acylcarnitine
types, associated with improved SDS scores in male patients undergoing HD. Univariate analysis
revealed that low baseline butyryl- and isovaleryl-/2-methylbutyryl-carnitine levels were significantly
correlated with SDS scores after treatment. Multiple regression analysis revealed that butyrylcarnitine
levels were a sole independent predictor of SDS scores after treatment (r2 = 0.533).
Conclusion: L-carnitine supplementation for 3 months improved the depression state in uremic male
patients undergoing HD. Thus, low butyryl-carnitine levels may predict the clinical response to
L-carnitine supplementation in male patients undergoing HD and who have mild depression.