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  2. Angiotensin AT2-receptor stimulation improves survival and neurological outcome after experimental stroke in mice

Angiotensin AT2-receptor stimulation improves survival and neurological outcome after experimental stroke in mice

  • J Mol Med (Berl). 2016 Aug;94(8):957-66. doi: 10.1007/s00109-016-1406-3.
Katja Schwengel 1 Pawel Namsolleck 2 Kristin Lucht 1 Bettina H Clausen 3 Kate L Lambertsen 3 Veronica Valero-Esquitino 1 Christa Thöne-Reineke 4 Susanne Müller 5 Robert E Widdop 6 Kate M Denton 7 Masatsugu Horiuchi 8 Masaru Iwai 8 Francesco Boato 9 Björn Dahlöf 10 Anders Hallberg 11 Thomas Unger 2 U Muscha Steckelings 12
Affiliations

Affiliations

  • 1 Center for Cardiovascular Research, Medical Faculty, Charité, Berlin, Germany.
  • 2 CARIM, Maastricht University, Maastricht, The Netherlands.
  • 3 Department of Neurobiology, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark.
  • 4 Department of Veterinary Medicine, Free University, Berlin, Germany.
  • 5 Experimental Neurology, Medical Faculty, Charité, Berlin, Germany.
  • 6 Department of Pharmacology, Monash University, Clayton, Australia.
  • 7 Department of Physiology, Monash University, Clayton, Australia.
  • 8 Department of Molecular Cardiovascular Biology and Pharmacology, Ehime University, Ehime, Japan.
  • 9 Burke Medical Research Institute, Weill Cornell Medical College, Cornell University, White Plains, USA.
  • 10 Sahlgrenska University Hospital, Gothenburg, Sweden.
  • 11 Department of Medicinal Chemistry, Uppsala University, Uppsala, Sweden.
  • 12 Department of Cardiovascular and Renal Research, Institute for Molecular Medicine, University of Southern Denmark, Odense, Denmark. usteckelings@health.sdu.dk.
Abstract

This study investigated the effect of post-stroke, direct AT2-receptor (AT2R) stimulation with the non-peptide AT2R-agonist compound 21 (C21) on infarct size, survival and neurological outcome after middle cerebral artery occlusion (MCAO) in mice and looked for potential underlying mechanisms. C57/BL6J or AT2R-knockout mice (AT2-KO) underwent MCAO for 30 min followed by reperfusion. Starting 45 min after MCAO, mice were treated once daily for 4 days with either vehicle or C21 (0.03 mg/kg ip). Neurological deficits were scored daily. Infarct volumes were measured 96 h post-stroke by MRI. C21 significantly improved survival after MCAO when compared to vehicle-treated mice. C21 treatment had no impact on infarct size, but significantly attenuated neurological deficits. Expression of brain-derived neurotrophic factor (BDNF), tyrosine kinase receptor B (TrkB) (receptor for BDNF) and growth-associated protein 43 (GAP-43) were significantly increased in the peri-infarct cortex of C21-treated mice when compared to vehicle-treated mice. Furthermore, the number of apoptotic neurons was significantly decreased in the peri-infarct cortex in mice treated with C21 compared to controls. There were no effects of C21 on neurological outcome, infarct size and expression of BDNF or GAP-43 in AT2-KO mice. From these data, it can be concluded that AT2R stimulation attenuates early mortality and neurological deficits after experimental stroke through neuroprotective mechanisms in an AT2R-specific way. Key message • AT2R stimulation after MCAO in mice reduces mortality and neurological deficits.• AT2R stimulation increases BDNF synthesis and protects neurons from Apoptosis.• The AT2R-agonist C21 acts protectively when applied post-stroke and peripherally.

Keywords

AT2-receptor; MCAO; Neuroprotection; Renin-angiotensin system; Stroke.

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