title: Exendin-4 reduces ischemic brain injury in normal and aged type 2 diabetic mice and promotes microglial M2 polarization.
abstract: Exendin-4 is a glucagon-like receptor 1 agonist clinically used against type 2 diabetes that has also shown neuroprotective effects in experimental stroke models. However, while the neuroprotective efficacy of Exendin-4 has been thoroughly investigated if the pharmacological treatment starts before stroke, the therapeutic potential of the Exendin-4 if the treatment starts acutely after stroke has not been clearly determined. Further, a comparison of the neuroprotective efficacy in normal and aged diabetic mice has not been performed. Finally, the cellular mechanisms behind the efficacy of Exendin-4 have been only partially studied. The main objective of this study was to determine the neuroprotective efficacy of Exendin-4 in normal and aged type 2 diabetic mice if the treatment started after stroke in a clinically relevant setting. Furthermore we characterized the Exendin-4 effects on stroke-induced neuroinflammation. Two-month-old healthy and 14-month-old type 2 diabetic/obese mice were subjected to middle cerebral artery occlusion. 5 or 50 µg/kg Exendin-4 was administered intraperitoneally at 1.5, 3 or 4.5 hours thereafter. The treatment was continued (0.2 µg/kg/day) for 1 week. The neuroprotective efficacy was assessed by stroke volume measurement and stereological counting of NeuN-positive neurons. Neuroinflammation was determined by gene expression analysis of M1/M2 microglia subtypes and pro-inflammatory cytokines. We show neuroprotective efficacy of 50 µg/kg Exendin-4 at 1.5 and 3 hours after stroke in both young healthy and aged diabetic/obese mice. The 5 µg/kg dose was neuroprotective at 1.5 hour only. Proinflammatory markers and M1 phenotype were not impacted by Exendin-4 treatment while M2 markers were significantly up regulated. Our results support the use of Exendin-4 to reduce stroke-damage in the prehospital/early hospitalization setting irrespectively of age/diabetes. The results indicate the polarization of microglia/macrophages towards the M2 reparative phenotype as a potential mechanism of neuroprotection.
authors.affiliation: Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Internal Medicine, Stockholm, Sweden.
authors.forename: Vladimer
authors.initials: V
authors.lastname: Darsalia
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Sansan
authors.initials: S
authors.lastname: Hua
authors.affiliation: Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Internal Medicine, Stockholm, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Larsson
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Carina
authors.initials: C
authors.lastname: Mallard
authors.affiliation: Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Internal Medicine, Stockholm, Sweden.
authors.forename: David
authors.initials: D
authors.lastname: Nathanson
authors.affiliation: Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Internal Medicine, Stockholm, Sweden.
authors.forename: Thomas
authors.initials: T
authors.lastname: Nyström
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, Alabama, United States of America; Department of Internal Medicine, Diabetes Research Unit, Södertälje Hospital, Södertälje, Sweden.
authors.forename: Åke
authors.initials: Å
authors.lastname: Sjöholm
authors.affiliation: Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Maria E
authors.initials: ME
authors.lastname: Johansson
authors.affiliation: Karolinska Institutet, Department of Clinical Science and Education, Södersjukhuset, Internal Medicine, Stockholm, Sweden.
authors.forename: Cesare
authors.initials: C
authors.lastname: Patrone
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002545:Brain Ischemia / Q000473:pathology / Q000517:prevention & control*; D003921:Diabetes Mellitus, Experimental; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D004353:Drug Evaluation, Preclinical; D000077270:Exenatide; D020869:Gene Expression Profiling; D020244:Infarction, Middle Cerebral Artery; D008297:Male; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000378:metabolism / Q000473:pathology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D010641:Phenotype; D020521:Stroke / Q000188:drug therapy* / Q000473:pathology; D013997:Time Factors; D014688:Venoms / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D018696:Neuroprotective Agents; D010455:Peptides; D014688:Venoms; D000077270:Exenatide
references.citation: J Leukoc Biol. 2010 May;87(5):779-89
references.pmid: 20130219
references.citation: J Neurol Sci. 2008 Apr 15;267(1-2):187-8
references.pmid: 18068188
references.citation: Trends Neurosci. 2007 Sep;30(9):433-9
references.pmid: 17765332
references.citation: J Neurosci. 2013 Jul 17;33(29):12041-51
references.pmid: 23864690
references.citation: J Cereb Blood Flow Metab. 1996 Jul;16(4):605-11
references.pmid: 8964799
references.citation: Stroke. 2008 Feb;39(2):523-4
references.pmid: 18202309
references.citation: Clin Sci (Lond). 2012 May 1;122(10):473-83
references.pmid: 22150224
references.citation: J Neurosurg. 2013 May;118(5):1072-85
references.pmid: 23331000
references.citation: Neuroreport. 2009 Aug 26;20(13):1161-6
references.pmid: 19617854
references.citation: J Neurosci Res. 2011 Jul;89(7):1103-13
references.pmid: 21472764
references.citation: Int J Obes Relat Metab Disord. 2003 Mar;27(3):313-8
references.pmid: 12629557
references.citation: Regul Pept. 2005 Jun 15;128(2):117-24
references.pmid: 15780431
references.citation: J Clin Invest. 2012 Mar;122(3):787-95
references.pmid: 22378047
references.citation: Br J Pharmacol. 2010 Feb 1;159(3):495-501
references.pmid: 20128800
references.citation: Neurochem Int. 2013 Oct;63(4):291-301
references.pmid: 23811611
references.citation: Trends Neurosci. 1999 Sep;22(9):391-7
references.pmid: 10441299
references.citation: J Neurosci. 2009 Oct 28;29(43):13435-44
references.pmid: 19864556
references.citation: Stroke. 2009 Jun;40(6):2244-50
references.pmid: 19246690
references.citation: J Endocrinol. 2014 Mar 07;221(1):T31-41
references.pmid: 23999914
references.citation: J Neurol. 2009 Oct;256(10):1603-19
references.pmid: 19399381
references.citation: Brain Res. 2012 Jan 3;1427:23-34
references.pmid: 22055454
references.citation: Neurology. 2004 May 11;62(9):1558-62
references.pmid: 15136681
references.citation: Nat Med. 2011 Nov 07;17(11):1391-401
references.pmid: 22064429
references.citation: Cochrane Database Syst Rev. 2011 Oct 05;(10):CD006423
references.pmid: 21975753
references.citation: Stroke. 2002 Aug;33(8):2123-36
references.pmid: 12154275
references.citation: Neurology. 2005 Feb 22;64(4):654-9
references.pmid: 15728287
references.citation: Stroke. 2012 Nov;43(11):3063-70
references.pmid: 22933588
references.citation: Cerebrovasc Dis. 2004;17 Suppl 1:153-66
references.pmid: 14694293
references.citation: Proc Natl Acad Sci U S A. 2009 Jan 27;106(4):1285-90
references.pmid: 19164583
references.citation: Lancet. 2006 Nov 11;368(9548):1696-705
references.pmid: 17098089
references.citation: Neurosci Res. 2006 Aug;55(4):352-60
references.pmid: 16720054
references.citation: J Cereb Blood Flow Metab. 2011 Aug;31(8):1696-705
references.pmid: 21487412
references.citation: N Engl J Med. 1995 Dec 14;333(24):1581-7
references.pmid: 7477192
references.citation: Stroke. 1997 Aug;28(8):1530-40
references.pmid: 9259745
references.citation: J Neurochem. 2012 Nov;123 Suppl 2:29-38
references.pmid: 23050640
references.citation: Exp Neurol. 2004 May;187(1):94-104
references.pmid: 15081592
references.citation: Stroke. 2009 Jul;40(7):2438-41
references.pmid: 19478213
references.citation: Neurology. 2012 Jul 24;79(4):306-13
references.pmid: 22622858
references.citation: Stroke. 2014 Feb;45(2):640-4
references.pmid: 24399376
references.citation: Br J Pharmacol. 2012 Jul;166(5):1586-99
references.pmid: 22519295