Possible role of angiotensin-converting enzyme 2 and activation of angiotensin II type 2 receptor by angiotensin-(1-7) in improvement of vascular remodeling by angiotensin II type 1 receptor blockade

Hypertension. 2014 Mar;63(3):e53-9. doi: 10.1161/HYPERTENSIONAHA.113.02426. Epub 2013 Dec 30.

Abstract

Cross talk between the angiotensin-converting enzyme (ACE)/angiotensin II (Ang II)/Ang II type 1 (AT1) receptor axis and the ACE2/Ang-(1-7)/Mas axis plays a role in the pathogenesis of cardiovascular remodeling. Furthermore, possible stimulation of the Ang II type 2 (AT2) receptor by Ang-(1-7) has been highlighted as a new pathway. Therefore, we examined the possibility of whether the ACE2/Ang-(1-7)/Mas axis and Ang-(1-7)/AT2 receptor axis are involved in the inhibitory effects of AT1 receptor blockers on vascular remodeling. Wild-type, Mas-knockout, and AT2 receptor knockout mice were used in this study. Vascular injury was induced by polyethylene-cuff placement around the mouse femoral artery. Some mice were treated with azilsartan, an AT1 receptor blocker, or Ang-(1-7). Neointimal formation 2 weeks after cuff placement was more marked in Mas-knockout mice compared with wild-type mice. Treatment with azilsartan or Ang-(1-7) attenuated neointimal area, vascular smooth muscle cell proliferation, increases in the mRNA levels of monocyte chemoattractant protein-1, tumor necrosis factor-α, and interleukin-1β, and superoxide anion production in the injured artery; however, these inhibitory effects of azilsartan and Ang-(1-7) were less marked in Mas-knockout mice. Administration of azilsartan or Ang-(1-7) attenuated the decrease in ACE2 mRNA and increased AT2 receptor mRNA but did not affect AT1 receptor mRNA or the decrease in Mas mRNA. The inhibitory effect of Ang-(1-7) on neointimal formation was less marked in AT2 receptor knockout mice compared with wild-type mice. These results suggest that blockade of the AT1 receptor by azilsartan could enhance the activities of the ACE2/Ang-(1-7)/Mas axis and ACE2/Ang-(1-7)/AT2 receptor axis, thereby inhibiting neointimal formation.

Keywords: angiotensin; angiotensin-converting enzyme 2; inflammation; oxidative stress; receptors; remodeling.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin I / pharmacology*
  • Angiotensin II Type 1 Receptor Blockers / pharmacology*
  • Angiotensin-Converting Enzyme 2
  • Animals
  • Disease Models, Animal
  • Gene Expression Regulation*
  • Immunohistochemistry
  • Mice
  • Mice, Inbred C57BL
  • Oxidative Stress
  • Peptide Fragments / pharmacology*
  • Peptidyl-Dipeptidase A / genetics*
  • Peptidyl-Dipeptidase A / metabolism
  • RNA / genetics*
  • RNA / metabolism
  • Real-Time Polymerase Chain Reaction
  • Receptor, Angiotensin, Type 2 / genetics*
  • Receptor, Angiotensin, Type 2 / metabolism
  • Vascular Resistance*
  • Vasodilator Agents / pharmacology

Substances

  • Angiotensin II Type 1 Receptor Blockers
  • Peptide Fragments
  • Receptor, Angiotensin, Type 2
  • Vasodilator Agents
  • RNA
  • Angiotensin I
  • Peptidyl-Dipeptidase A
  • Ace2 protein, mouse
  • Angiotensin-Converting Enzyme 2
  • angiotensin I (1-7)