Dimethylarginine levels and nutritional status in hemodialysis patients

Background: Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) originate from hydrolysis of methylated proteins, including dietary proteins, and are retained in end-stage renal disease (ESRD). This study aimed to detect the correlation of ADMA and SDMA to nutritional parameters in dialysis patients. Methods: Before and after a single dialysis session, L-arginine, ADMA and SDMA plasma levels were measured in 38 hemodialysis patients by HPLC-tandem mass spectrometry. Biochemistry, protein intake, anthropometry and bioelectric impedance analysis were evaluated Results: Predialysis plasma levels of ADMA were higher than in normal controls (n=20) (1.14 +/- 0.27 mu mol/L vs. 0.56 +/- 0.09 mu mol/L, p<0.001), as were SDMA levels (3.49 +/- 1.00 mu mol/L vs. 0.44 +/- 0.13 mu mol/L, p<0.001). On univariate analysis, predialysis ADMA levels were inversely related to BMI and albumin levels, whereas SDMA was directly related to nPNA, phase angle, prealbumin and creatinine serum levels. ADMA/SDMA ratio was inversely related to prealbumin and albumin, creatinine, urea and phosphorus serum levels, as well as nPNA, but positively to C-reactive protein. On multiple regression analysis, serum albumin and BMI were the stronger predictors of ADMA, whereas prealbumin serum levels followed by dietary protein intake were the stronger predictors of SDMA. Prealbumin followed by C-reactive protein was predictive of the ADMA/SDMA molar ratio. Conclusions: Our results confirm that ADMA and SDMA levels are increased in ESRD patients and suggest that a link may exist with inflammation and nutritional status. High ADMA levels associated with reduced SDMA may be a predictive marker of malnutrition-inflammation-atherosclerosis syndrome.