Plasma endothelin-1 is not increased in overweight/obese hypertensive African women

Endothelin-1 (ET-1) has been found to be higher in hypertensive African Americans and obese hypertensive Caucasians compared to normotensive controls with an enhanced ET-1-dependent vasoconstrictor tone. ET-1 levels and the associations thereof with cardiovascular function in overweight/obese normotensive and hypertensive African women have not been investigated. It is therefore hypothesized that ET-1 levels are elevated in overweight/obese hypertensive African women compared to overweight/obese and lean normotensive controls. Additionally, it is hypothesized that these elevated ET-1 levels are associated with increased total peripheral resistance (TPR) and decreased arterial compliance (C(W)).

A case-case control study was performed which included 98 African women. The subjects were divided into lean normotensive (lean NT), overweight/obese normotensive (OW/OB NT) and overweight/obese hypertensive (OW/OB HT). The Finometer apparatus was used to obtain a more elaborate cardiovascular profile and plasma immunoreactive ET-1 levels were determined.

ET-1 levels were similar for the three groups. Although a decrease in vascular function was observed in the OW/OB HT group, no correlations were obtained between ET-1 and the cardiovascular profile, before and after adjusting for age.

In African women, ET-1 levels did not differ between lean and overweight/obese and normotensive and hypertensive subjects. The lack of significant associations between ET-1 and decreased vascular function in the overweight/obese hypertensive group suggests that ET-1 is not implicated in obesity-related hypertension in African women.