THE ACTIVITY OF ANGIOTENSIN-CONVERTING ENZYME 2 AND OTHER COMPONENTS OF THE RENIN-ANGIOTENSIN SYSTEM (RAAS) DURING PROGRESSIVE AGE IN HYPERTENSIVE MEN

Abstract

Background: ACE2 and renin-angiotensin-aldosterone system (RAAS) are complex physiological systems that contribute to blood pressure control, whereas the activity and responsiveness of the ACE2 and RAAS be changed due to advanced age and hypertension. Aim: This study is to investigate the ACE2, Renin, Ang I, Ang II, and aldosterone levels in various ages of hypertensive men in order to provide insights into the effect of aging and high blood pressure on some body organs. Methods: It was compared ACE2, Renin, Ang I, Ang II, and aldosterone levels across 80 hypertensive men with ages between 30 years - 69 years. The persons were divided into four groups (20 men/group) according to their ages. The first group was 30-39 years, the second group was 40-49 years, the third group was 50-59 years, and the fourth group was 60-69. It used a one-way Analysis of Variance (ANOVA), followed by Duncan s test for the groups. Results: It was observed that the concentration of ACE2 decreased significantly in different groups with advanced age (p ≤ 0.01), except in the fourth sample group vs. the third group. The renin was reduced considerably in other groups with aging (p ≤ 0.01), except in the second sample group vs. the first group. The peptides Angiotensin I (Ang I) and Angiotensin II (Ang II) had opposite growth directions, decreasing and increasing, respectively, it was statistically significant (p ≤ 0.01). Also, aldosterone increased significantly in different groups with advanced age (p ≤ 0.01), not including the fourth group vs. the third group). Discussion: The physiological impact of these results is discussed according to the effects of hypertension and advanced age on all the studied parameters, particularly ACE2 deficiency and high levels of Ang II, pointed out an apparent dysfunction in blood pressure regulation during advanced age. Conclusions: ACE2 deficiency may be mediated by a series of dysfunctional events caused by the present changes in RAAS and other parameters in response to hypertension and advanced ages. Low renin levels and other following changes might cause an imbalance of Ang I and Ang II ratios. In addition, high levels of Ang II might reflect the unfavorable and negative changes that contributed to the disruption of many organs and systems during hypertension and advanced age.