Endothelial dysfunction is an initial step in the pathogenesis of cardiovascular diseases. Since we previously identified the G protein-coupled receptor Mas as a receptor for angiotensin (Ang)-(1–7), a heptapeptide with endothelium-dependent vasorelaxant properties, we investigated whether alterations on the Ang-(1–7)/Mas axis alter endothelial function.Results
Ang-(1–7)-mediated relaxation of murine wild-type mesenteric arteries was equally impaired in both wild-type arteries pretreated with the Ang-(1–7) receptor blocker, A779, and arteries isolated from Mas-deficient mice. Importantly, the response to the endothelium-dependent vasorelaxant, bradykinin (BK), and acetylcholine (ACh) effects were comparably inhibited, while endothelium-independent vessel relaxation by sodium nitroprusside was unaltered in these vessels. Hypothesizing endothelial dysfunction, we proved the in-vivo relevance of the ex-vivo findings investigating mesenteric properties after 1 week of minipump infusion of A779 in wild-type mice. Both BK- and ACh-induced relaxation were significantly impaired in wild-type vessels of pretreated animals. A779-induced impairment of endothelial function was confirmed in vitro, since BK-mediated nitric oxide (NO) release was increased by Ang-(1–7) and blunted by A779 pretreatment in primary human endothelial cell cultures.Conclusions
Our data highlight a pivotal role for the receptor Mas in preserving normal vascular relaxation. Consequently, Mas agonists arise as a promising tool in the treatment of cardiovascular diseases characterized by endothelial dysfunction.