Correlation between Plasma Carnitine, Muscle Carnitine and Glycogen Levels in Maintenance Hemodialysis Patients

Abstract

Chronic hemodialysis (HD) may lead to losses of carnitine from plasma and muscle. Plasma carnitine does not reflect the body content of carnitine. The purpose of this study was the evaluation of total and free plasma and muscle carnitine concentrations (TPC, FPC, TMC, FMC), muscle glycogen and the relationship between plasma and tissue carnitine content and the basic indices of lipid metabolism in HD patients. The studies were conducted in two groups: the first one consisted of 37 HD patients (19 F, 18 M), the second one served as the control and was composed of 29 (10 F, 19 M) patients with healthy kidneys. Tissue specimens in HD patients were taken during surgery on arterio-venous fistula from brachioradial muscle. Carnitine and glycogen measurements were performed using enzymatic methods according to Cederblad and Huijng respectively. Total cholesterol (CH), HDL-CH, and triglycerides were assayed by enzymatic commercial test system (Boehringer-Mannheim, Germany). To summarise, we found the following phenomena in our HD patients in comparison with the controls: 1) In plasma: similar TPC but decreased FPC levels and FPC/TPC ratio which may suggest free carnitine deficiency. 2) In muscle: significantly lower TMC and FMC levels but normal FMC/ITMC ratio. 3) Negative correlation between TMC and FMC levels and duration of dialysis treatment. 4) No correlation between plasma and muscle camitine concentration. 5) Significantly higher concentration of muscle glycogen which could be explained by the changes in the structure of muscle fibres in HD patients and/or lower physical activity. 6) A positive correlation between FPC/APC or FPC/TPC ratio and HDL-CH in HD patients which may suggest that an appropriate proportion between free and acylcarnitines may influence HDL-CH levels in that population.