Subtle changes in ADMA and l-arginine concentrations in normal pregnancies are unlikely to account for pregnancy-related increased flow-mediated dilatation

BACKGROUND: Our objective was to investigate whether serum concentrations of asymmetric dimethylarginine (ADMA) or l-arginine correlate to hyperlipidemia or endothelial function in normal pregnancy compared with the non-pregnant subjects. METHODS AND RESULTS: As a part of population-based, prospective cohort Cardiovascular Risk in Young Finns study conducted in Finland we examined 57 pregnant Finnish women throughout gestation and 62 control women matched for age and smoking. Serum glucose, triglycerides (TG), total cholesterol (TC), low-density cholesterol (LDL-C), high-density cholesterol (HDL-C) and ADMA, symmetric dimethylarginine (SDMA) and l-arginine were determined concomitantly with endothelium-dependent brachial artery flow-mediated dilation (FMD), measured by ultrasound. All serum lipid concentrations were significantly higher in pregnant women than in non-pregnant women (P < 0.001 for each). The mean serum ADMA concentration in pregnant women was significantly lower compared with the non-pregnant controls (0.513 micromol l(-1) +/- 0.0593 versus 0.577 micromol l(-1) +/- 0.0710, P < 0.001). Lowered ADMA concentrations did not correlate statistically to FMD in these healthy pregnant women but FMD was enhanced towards the end of pregnancy. CONCLUSIONS: ADMA and l-arginine concentrations fall in normal pregnancy despite marked hypercholesterolemia. Endothelium-dependent vasodilation is enhanced in normal pregnancy but is not statistically correlated to maternal serum ADMA or l-arginine concentrations.