Objective: Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase and is regarded as a novel risk factor for cardiovascular disease. ADMA concentrations are increased in blood of haemodialysis (HD) patients and may contribute to endothelial dysfunction in them. It was published that the metabolic pathways of ADMA are connected to the metabolic cycle of homocysteine. The aim of our study was to test a relation of ADMA to other cardiovascular risk factors in HD patients. Design: Observational study. Settings: Institute of Clinical Biochemistry and Haematology and 1st Department of Internal Medicine of Charles University Medical Faculty and Faculty Hospital, Pilsen, Czech Republic. Material and Methods: We analysed ADMA levels by ELISA method, total and HDL cholesterols, apolipoproteins AI (apoA) and B (apoB), triglycerides (TG), oxidized LDL (oxLDL), C-reactive protein measured by ultrasensitive method (CRP), lipoprotein (a), thiobarbituric acid reactive substances (TBARS) and homocysteine (Hcy) in plasma of 176 chronically HD patients (70 females, 106 males; mean age ± SD = 66.4 ± 10.63 years). ADMA levels were determined also in 73 healthy men (mean age ± SD = 48.15 ± 5.78). Comparison of ADMA concentration between the two studied groups was performed by the Wilcoxon unpaired test. Relations among variables in the group of HD patients were evaluated using the Spearman correlation. Independence of ADMA was assessed by multiple regression analysis. Results: Average ADMA concentration in HD patients was significantly higher than control values (1.13 ± 0.22, median = 1.14 µmol/l vs. 0.75 ± 0.15, median = 0.72 µmol/l; CI = 0.33 to 0.44, p < 0.001). Interesting correlations were found between BMI and oxLDL (r = 0.33, p < 0.001), apoA and CRP (r = -0.28, p < 0.001), apoB and oxLDL (r = 0.75, p < 0.001) and finally TG and oxLDL (r = 0.45, p < 0.001). No correlation was found between ADMA and Hcy (r = -0.07, p = 0.39). Multiple regression analysis revealed that ADMA is independent from BMI, age and all other measured parameters. Conclusion: ADMA is independent of all other measured cardiovascular risk factors including homocysteine in HD patients.

        Key words: asymmetric dimethylarginine, haemodialysis, cardiovascular risk factors, homocysteine, nitric oxide.