Determination of asymmetric and symmetric dimethylarginines in plasma of hyperhomocysteinemic subjects

The aim of this study was to investigate the possible relationship among dimethylarginines (asymmetric, ADMA; symmetric, SDMA) and homocysteine (Hcy) levels in subjects affected by chronic, mild to intermediate, hyperhomocysteinemia. ADMA and SDMA were assayed by an optimised HPLC method in 75 patients (Hcy = 20.8 (mu)mol/L, 17.1-30.2; median and percentile range) and, for comparison, in 85 healthy subjects (Hcy = 8.0 (mu)mol/L, 7.0-9.1). In controls, the cut-off values were set at 0.61 (mu)mol/L for ADMA and 0.56 or 0.48 (mu)mol/L for male and female SDMA, respectively. In patients, ADMA and SDMA levels were increased (p<0.001) with respect to controls, but no correlation with Hcy was observed. Hyperhomocysteinemic subjects showed a different behaviour in respect to ADMA and SDMA levels and this allowed their stratification in 3 subgroups characterized by ADMA and SDMA in the normal range, only SDMA, or both ADMA and SDMA over the cut-off values. A lack of correlation with Hcy was again observed, thus minimizing the direct role of Hcy on ADMA and SDMA metabolism and suggesting the need for further studies on this issue. (copyright) Springer-Verlag 2005.