Plasma concentrations of endothelial vasoactive substances in clinically healthy subjects. Associations with urinary albumin excretion and ambulatoryblood pressure

Elevated urinary albumin excretion (UAE) is a predictor of cardiovascular d isease, and one possible explanation is that elevated UAE reflects a genera lized vascular dysfunction. The present study tests whether the plasma conc entrations of the two main endothelial vasoactive substances (nitric oxide and endothelin-1 [ET-1]) are changed in clinically healthy subjects with el evated UAE (> 6.6 mu g/min-the 90th percentile in the background population ) and to test associations between these concentrations and systemic blood pressure. Twenty-seven subjects with elevated UAE were compared with 46 mat ched controls with normoalbuminuria. Plasma concentration of ET-1 was measu red using an ELISA method and plasma concentration of nitrate/nitrite using a photometric method. Twenty-four-hour blood pressure was measured using a portable recorder (TM-2421). No significant differences in the concentrati ons of nitrate/nitrite and ET-1 were found between the groups, e.g. 21 (10- 105) vs. 18 (11-152) (p = 0.33) and 0.98 (0.58 - 1.95) vs. 1.10 (0.54 - 1.5 0) (p = 0.27), respectively. However, plasma nitrate/nitrite was significan tly positively correlated to systolic and diastolic blood pressure in subje cts with normoalbuminuria but not in subjects with elevated UAE. In contras t, plasma ET-1 concentration was significantly positively correlated to sys tolic blood pressure only in subjects with elevated UAE. In conclusion, ele vated UAE is not associated with changed plasma concentrations of endotheli al vasoactive substances in clinically healthy subjects. However, nitrate/n itrite is positively correlated to BP only in subjects with normoalbuminuri a, and ET-1 is positively correlated to BP only in subjects with elevated U AE.