Abstract 392: Sexual Dichotomy in Blood Pressure Regulation: Is Ang (1-7) a Key Player?
The prevalence of cardiovascular disease is greater in men than in women, and although the mechanism responsible is unknown, sex differences in Angiotensin (Ang) peptides have been suggested to contribute. In fact, evidence in rats indicates Ang (1-7), a vasodilatory peptide, is higher in females when compared to males. In humans, the flow-mediated dilation (FMD) test represents a bioassay of NO-dependent vasodilation and is a predictor of future cardiovascular disease. This study sought to test the hypotheses that 1) Ang (1-7) is higher in women compared to men, and 2) determine if relationships exist among concentrations of Ang (1-7), FMD, and blood pressure. A total of 29 subjects participated in this study; FMD was obtained on 14 (7 men; 7 women). Following an overnight fast, blood pressure and FMD were performed and blood samples were collected. Systolic blood pressure was greater in men (121±5 mm Hg) compared to women (101±3 mm Hg; p=0.01); however, no difference in diastolic blood pressure was observed (66±4 vs. 63±2 mm Hg, respectively). Plasma concentrations of Ang (1-7) were significantly higher in women compared to men (43±5 vs. 32±4 pg/mL; p=0.04). FMD was positively associated with Ang (1-7) independent of sex (r=0.592; p=0.02); however, the relationship between Ang (1-7) and diastolic blood pressure was evident only in women (women r=-0.717; p=0.07 and men r=0.186; p=0.69). These data support a sexual dimorphism in Ang (1-7) in humans, similar to what we have observed previously in our animal model. For the first time in humans, we have also observed a sex dependent relationship between Ang (1-7) and diastolic blood pressure supporting the hypotheses that Ang (1-7) may play an important role in BP regulation and maintenance of endothelial function particularly in women. These data may provide insight into the cardiovascular disease risk disparity between sexes.
- © 2012 by American Heart Association, Inc.