Asymmetric Dimethylarginine, Blood Pressure, and Renal Perfusion in Elderly Subjects

Abstract

Background— Reduced availability of nitric oxide (NO) is thought to contribute to the age-associated increase of renovascular tone and blood pressure. We assessed blood concentrations of the endogenous NO synthase inhibitor asymmetric dimethylarginine (ADMA) as well as renal hemodynamics, comparing young (n=24, 13 men, 25±1 years) and elderly (n=24, 13 men, 69±2 years) healthy subjects and elderly subjects with essential hypertension (n=24, 13 men, 70±2 years). Methods and Results— Plasma ADMA concentration and renovascular resistance (RVR) were significantly higher (P<0.05) and effective renal plasma flow (ERPF) significantly lower (P<0.05) in elderly (2.77±0.20 μmol/L, 125±10 mm Hg/mL per minute, 487±26 mL/min per 1.73 m2) than in young healthy subjects (1.30±0.11, 77±3, 654±18). Both ADMA levels and RVR were higher and ERPF lower in the hypertensive elderly subjects (3.53±0.23, 163±11, 427±19; P<0.05 versus both groups). In contrast, plasma concentrations of the biologically inactive stereoisomer symme...