Hypertension and menopause: Positive effects of angiotensin converting enzyme inhibition on nitric oxide system and oxidative stress in kidney.

JUDITH ZILBERMAN; ANALIA TOMAT; MARIANA ROMERO; ROSANA ELESGARAY; MARÍA ÁNGELES COSTA; CRISTINA ARRANZ

Milan, Italia

Congreso; Nineteenth European Meeting of Hypertension.; 2009

After menopause the levels of sexual hormones change and cardiovascular risk augment. Estradiol may provide cardiovascular protection by controlling components of the renin angiotensin system, regulating AT1 receptors and reducing angiotensin I-converting enzyme (ACE) and probable decreasing reactive oxygen species. Moreover, the precise mechanisms of action leading to the pathogenesis of essential hypertension and renal damage in menopausal women remain unknown. Objective: To evaluate the effects of the ACE inhibitor enalapril on systolic blood pressure (SBP), oxidative stress and NO synthase (NOS) activity in the kidney in postmenopausal spontaneously hypertensive rats (SHR) Methods: SHR aged 16 month received enalapril (SHR-E, 250 mg/L in drinking water) or tap water (SHR-C) for 30 days. At the end of the treatment lipid peroxidation end products (TBARS), catalase (CAT), glutathion peroxidase (GPx) and NOS activity were measured in renal cortex and medulla. Results: Treatment with enalapril decreased SBP and TBARS and increased GPx and NOS activity in SHR. SBP (mmHg) TBARS (ng/mg.prot) CAT (pmol/mg.prot) GPx (pmol/min.mg. prot) NOS activity (pmol.citrulline 14C/g tissue. min) Cortex NOS activity (pmol.citrulline 14C/g tissue. min) Medulla SHR-C n=6 174±8 0.15±0.02 0.377±0.016 7.60±0.17 395.3±7.1 496.0±7.3 SHR-E n=6 152±9# 0.09±0.01* 0.473±0.040* 8.84±0.37* 471.4±3.8* 584.8±7.4* * p<0.05 or #p<0.01 vs control. Conclusions: Our results give evidences that ACE inhibition improves nitric oxide system and decreases oxidative stress in kidney in postmenopausal hypertensive rats. The mechanisms involved might be related to changes in estrogens axis or its receptors. These data clearly support therapeutics benefits of inhibition of rennin angiotensin system in hypertensive menopausal women.