Effects of long-term transdermal hormone replacement therapy on the renin–angiotensin– aldosterone system, plasma bradykinin levels and blood pressure in normotensive postmenopausal women

Aim:  This study was designed to investigate the effects of 24-month long-term transdermal hormone replacement therapy (HRT) on the circulating levels of components of the renin–angiotensin–aldosterone system (RAAS) and bradykinin, blood pressure (BP) and lipid profile in normotensive postmenopausal women (PMW).

Methods:  Twenty-two normotensive PMW were randomized to receive transdermal HRT (continuous 17-β estradiol patch at 36 µg/day plus cyclic oral medroxyprogesterone acetate 2.5 mg/day for 12 days/month) (n = 12) or control (n = 10). The plasma renin activity (PRA), serum angiotensin-converting enzyme (ACE) activity, plasma angiotensin (Ang) I, Ang II, aldosterone, bradykinin, and BP were measured before, and 12 and 24 months after, the start of the HRT.

Results:  In the HRT group, the diastolic BP and mean BP were significantly decreased at 12 and 24 months (both P < 0.05) after the start of therapy, however, no significant change of the systolic BP was noted during the study period. No changes in the RAAS components or lipid profile were noted in either group. The plasma bradykinin levels were significantly reduced at 12 (P < 0.05) and 24 months (P < 0.01), while no changes were observed in the control group.

Conclusion:  More than 12 months of long-term transdermal HRT kept diastolic BP, mean BP and plasma bradykinin levels decreased in normotensive PMW, without influencing any of the components of the RAAS. This therapy may allow optimal blood pressure control and prevent elevation of the cardiovascular risk.