Counter-regulatory effects played by the ACE - Ang II-AT1 and ACE2-Ang-(1-7) - Mas axes on the reactive oxygen species-mediated control of vascular function:perspectives to pharmacological approaches in controlling vascular complications

The Renin-Angiotensin system plays an important role in the regulation of systemic blood pressure as well as in fluid and electrolyte balance. It is divided into two described axes, the ACE - Ang II - AT1 receptor, with Ang II as the main mediator, and the ACE2 - Ang-(1 - 7) - Mas receptor, with Ang-(1 - 7) responsible for the main effects. The main vascular effect induced by Ang II is contraction, while Ang-(1 - 7) includes relaxation in several vascular beds. Ang II also activates several cytokines that are important in the genesis of vascular inflammation and hypertrophy. In this context, Ang-(1 - 7) seems to have a protective role. Both AT, and Mas receptors modulate, in different ways, the generation of, which are involved in the control of vascular tone and the genesis of vascular dysfunction triggered by several diseases, including diabetes mellitus, arterial hypertension and atherosclerosis. Thereby, this review presents an overview of the modulation played by the whole Renin-Angiotensin system on the reactive oxygen species-mediated control of vascular tone and the oxidative stress-elicited vascular dysfunction. (AU)