Elevated concentration of asymmetric dimethylarginine (ADMA) in individuals with metabolic syndrome

The metabolic syndrome (MS) is a cluster of pathophysiological alterations that includes the presence of hypertension, insulin resistance, dyslipidemia, and abdominal obesity. MS is associated with increased risk of developing diabetes and cardiovascular diseases. Endothelial dysfunction with impaired nitric oxide (NO) bioavailability has been implicated in insulin resistance and hypertension. NO is synthesized by nitric oxide synthase (NOS) using l-arginine as substrate. Asymmetric dimethyl arginine (ADMA) is a major and potent endogenous NOS inhibitor, associated with cardiovascular and renal diseases. We tested the hypothesis that plasmatic ADMA levels are increased in patients with MS. We studied 85 adult individuals from Talca, Chile, separated in two groups, 48 individuals with MS (according to modified ATP III criteria), and 37 individuals without MS as controls. ADMA levels were significantly increased in the MS group (mean±standard deviation 0.71±0.38 vs. 0.48±0.28μmol/L, p=0.0009). Furthermore, the levels of ADMA were modestly but significantly correlated with waist circumference (p=0.01) but not with the other components of MS (blood pressure, glycemia, triglycerides and high density lipoprotein cholesterol HDL-c). These results suggest a possible link between increased ADMA levels and the MS.