The effect of n-3 fatty acids on levels of methylarginines in patients with end-stage renal disease

Background: Patients with end-stage renal disease (ESRD) have a very high mortality mainly caused by cardiovascular disease (CVD). It has been suggested that plasma concentrations of asymmetric dimethyl arginine (ADMA), an endogenous nitric oxide synthase inhibitor, are markedly elevated in patients with ESRD. Elevation of ADMA is linked to CVD and an adverse prognosis. Supplementation with n-3 fatty acids has previously been shown to prevent CVD, but there is very little data regarding the effect of n-3 fatty acids on levels of ADMA. Methods: Patients with ESRD and documented CVD were randomized to treatment with 1.7 g of n-3 fatty acids (n=103, 34% women) or olive oil (n=103, 38% women) for three months. ADMA, symmetric dimethyl arginine (SDMA), L-arginine, and the relative content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in serum phospholipids were measured before and after treatment. Results: ADMA was normally distributed with a mean value of 0.56 +/- 0.13 mu mol/L (range 0.21-1.01) and only 14/206 (6.8 %) had elevated levels of ADMA. SDMA was generally elevated with a mean value of 1.88 +/- 0.64 mu mol/L (range 0.67-4.56). Supplementation with n-3 fatty acids for three months did not change plasma levels of ADMA, SDMA or L-arginine. Conclusions: The present data do not support a beneficial effect of n-3 fatty acids on methylarginines in patients with ESRD.