Effects of different angiotensin II type 1 receptor blockers on regulation of ACE-Ang II-AT1 and ACE2-Ang(1-7)-Mas axes in pressure overload-induced cardiac remodeling in male mice / 中国病理生理杂志

ABSTRACT

AIM:To examine and compare the effects of several ARBs that are widely used in clinics , on the ACE-Ang II-AT1 receptor and the ACE2-Ang(1-7)-Mas axis during the development of cardiac remodeling after pressure overload .METHODS: All of the mice used in the study underwent transverse aortic constriction (TAC) or sham operation for 2 or 4 weeks.A solution of either ARBs or sa-line was administered through a stomach tube 3 days before the operation .Meanwhile , to eliminate the influence of Ang II , a recombi-nant adenovirus expressing small interfering RNAs targeting angiotensinogen ( Ad-ATG siRNA) was injected via the tail vein .The sur-gery was then performed and the drug was administered as mentioned above .Cardiac function and remodeling were evaluated by echo-cardiography , hemodynamic measurements and cardiac histology .Western blotting was used to determine the protein expression levels . Meanwhile , we performed similar experiments using ARBs with or without ATG siRNA in cardiomyocytes induced by mechanical stretch.RESULTS:Although all of the six ARBs , none of which repressed the elevation of left ventricular pressure after TAC , attenu-ated the development of cardiac hypertrophy and heart failure in the wild-type mice, the degree of attenuation by Olmesartan , Candesar-tan and Losartan tended to be larger than that of the other three drugs tested .Additionally , the degree of downregulation of the ACE-Ang II-AT1 axis and upregulation of the ACE2-Ang(1-7)-Mas axis was higher in response to Olmesartan, Candesartan and Losartan administration in vivo and in vitro.Additionally, Olmesartan had a larger influence when administered long term .However, the expres-sion of ACE was not influenced by the administration of ARBs in vivo and in vitro.Moreover, in angiotensinogen-knockdown mice, TAC-induced cardiac hypertrophy and heart failure were inhibited by Olmesartan , Candesartan and Losartan but not by Telmisartan , Valsartan and Irbesartan administration .Furthermore , only Olmesartan and Candesartan could downregulate the ACE-Ang II-AT1 axis and upregulate the ACE2-Ang(1-7)-Mas axis in vitro.CONCLUSION: Olmesartan, Candesartan and Losartan could effectively in-hibit pressure overload-induced cardiac remodeling even when with knockdown of Ang II , possibly through upregulation of the expres-sion of the ACE2-Ang(1-7)-Mas axis and downregulation of the expression of the ACE-Ang II-AT1 axis.In contrast, Telmisartan, Valsartan and Irbesartan only played a role in the presence of Ang II , and Losartan had no effect in the presence of Ang II in vitro.