Dyslipidemia, oxidative stress and cardiac dysfunction in children with chronic renal failure: effects of L-carnitine supplementation.

BACKGROUND: Secondary carnitine deficiency may develop in chronic renal failure (CRF) patients undergoing long-term hemodialysis (HD), with a resulting higher incidence of cardiovascular diseases, dyslipidemia and oxidative stress. We studied the efficacy of 12 months of L-carnitine supplementation on the amelioration of dyslipidemia, oxidative stress and cardiac dysfunction in 24 CRF children undergoing long-term HD compared with 24 age- and sex-matched controls.

METHODS: Plasma samples were analyzed spectrophotometerically before and after dialysis sessions and after 2-month supplementation with oral L-carnitine (50 mg/kg/day) for free carnitine (FC), the lipid profile, and oxidative stress markers. Echocardiography the day following dialysis measured cardiac diameters, wall thicknesses, left ventricular mass index (MI), end diastole and systole volume indices and functions.

RESULTS: The pre-dialysis FC concentration was substantially lower than controls and decreased significantly at the end of the dialysis session. Pre- and post-dialysis plasma levels of free fatty acids (FFAs), trigyleride (TG), total cholesterol (TC) and oxidative stress markers significantly increased while high-density lipoprotein cholesterol (HDL-C) and phospholipids significantly decreased compared to controls. Echocardiography detected a significant increase in cardiac diameters and thickness, and systolic and diastolic cardiac dysfunction. After L-carnitine supplementation, plasma levels of FC increased to normal levels. FFAs, TC and HDL-C returned to control levels while TG, phospholipids, and the oxidative stress markers decreased but remained significantly higher than controls. There was a significant decrease in cardiac diameters and an increase in left ventricular diastolic function (E/A ratio), but no correlation between FC levels and echocardiographic parameters. Pre-dialysis, post-dialysis and after treatment, plasma FC level showed a significant positive correlation with HDL-C and phospholipids and a significant negative correlation with each of oxidative stress markers, FFAs, TG and TC. On the other hand, FFAs showed a significant positive correlation with TG, TC, DC, NO and a significant negative correlation with HDL-C and phospholipids.

CONCLUSION: This study demonstrates that CRF children under regular HD suffer from a decrease in the level of plasma FC, dyslipidemia, oxidative stress, and an increase in cardiac diameters and thickness with impairment of cardiac functions. Oral L-carnitine supplementation at a dose of 50 mg/kg for 2 months can increase plasma FC level, improve dyslipidemia, decrease oxidative stress with reduction of cardiac diameters and increase in diastolic function.