Assessing the effects of Ang-(1-7) therapy following transient middle cerebral artery occlusion

Sci Rep. 2019 Feb 28;9(1):3154. doi: 10.1038/s41598-019-39102-8.

Abstract

The counter-regulatory axis, Angiotensin Converting Enzyme 2, Angiotensin-(1-7), Mas receptor (ACE2/Ang-1-7/MasR), of the renin angiotensin system (RAS) is a potential therapeutic target in stroke, with Ang-(1-7) reported to have neuroprotective effects in pre-clinical stroke models. Here, an extensive investigation of the functional and mechanistic effects of Ang-(1-7) was performed in a rodent model of stroke. Using longitudinal magnetic resonance imaging (MRI) it was observed that central administration of Ang-(1-7) following transient middle cerebral artery occlusion (MCAO) increased the amount of tissue salvage compared to reperfusion alone. This protective effect was not due to early changes in blood brain barrier (BBB) permeability, microglia activation or inflammatory gene expression. However, increases in NADPH oxidase 1 (Nox1) mRNA expression were observed in the treatment group compared to control. In order to determine whether Ang-(1-7) has direct cerebrovascular effects, laser speckle contrast imaging (LSCI) was performed to measure dynamic changes in cortical perfusion following reperfusion. Delivery of Ang-(1-7) did not have any effect on cortical perfusion following reperfusion however; it showed an indication to prevent the 'steal phenomenon' within the contralateral hemisphere. The comprehensive series of studies have demonstrated a moderate protective effect of Ang-(1-7) when given alongside reperfusion to increase tissue salvage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin I / pharmacology*
  • Angiotensin-Converting Enzyme 2
  • Animals
  • Blood-Brain Barrier / drug effects
  • Contrast Media / pharmacology
  • Disease Models, Animal
  • Gene Expression Regulation / drug effects
  • Humans
  • Infarction, Middle Cerebral Artery / diagnostic imaging
  • Infarction, Middle Cerebral Artery / drug therapy*
  • Infarction, Middle Cerebral Artery / genetics
  • Infarction, Middle Cerebral Artery / physiopathology
  • Inflammation / diagnostic imaging
  • Inflammation / drug therapy
  • Inflammation / genetics
  • Inflammation / pathology
  • Magnetic Resonance Imaging
  • Microglia / drug effects
  • Microglia / pathology
  • Middle Cerebral Artery / diagnostic imaging
  • Middle Cerebral Artery / drug effects
  • NADPH Oxidase 1 / genetics*
  • Neuroprotective Agents
  • Peptide Fragments / pharmacology*
  • Peptidyl-Dipeptidase A / genetics*
  • Proto-Oncogene Mas
  • RNA, Messenger / genetics
  • Rats
  • Renin-Angiotensin System / genetics
  • Reperfusion / methods
  • Stroke / diagnostic imaging
  • Stroke / drug therapy*
  • Stroke / genetics
  • Stroke / pathology

Substances

  • Contrast Media
  • MAS1 protein, human
  • Neuroprotective Agents
  • Peptide Fragments
  • Proto-Oncogene Mas
  • RNA, Messenger
  • Angiotensin I
  • NADPH Oxidase 1
  • Peptidyl-Dipeptidase A
  • ACE2 protein, human
  • Ace2 protein, rat
  • Angiotensin-Converting Enzyme 2
  • angiotensin I (1-7)