title: Rapamycin up-regulation of autophagy reduces infarct size and improves outcomes in both permanent MCAL, and embolic MCAO, murine models of stroke.
abstract: OBJECTIVE
  The role of autophagy in response to ischemic stroke has been confusing with reports that both enhancement and inhibition of autophagy decrease infarct size and improve post-stroke outcomes. We sought to clarify this by comparing pharmacologic modulation of autophagy in two clinically relevant murine models of stroke.
  
  
  METHODS
  We used rapamycin to induce autophagy, and chloroquine to block completion of autophagy, by treating mice immediately after stroke and at 24 hours post-stroke in two different models; permanent Middle Cerebral Artery Ligation (MCAL), which does not allow for reperfusion of distal trunk of middle cerebral artery, and Embolic Clot Middle Cerebral Artery Occlusion (eMCAO) which allows for a slow reperfusion similar to that seen in most human stroke patients. Outcome measures at 48 hours post-stroke included infarct size analysis, behavioral assessment using Bederson neurological scoring, and survival.
  
  
  RESULTS
  Chloroquine treatment reduced the lesion size by approximately 30% and was significant only in the eMCAO model, where it also improved the neurological score, but did not increase survival. Rapamycin reduced lesion size by 44% and 50% in the MCAL and eMCAO models, respectively. Rapamycin also improved the neurological score to a greater degree than chloroquine and improved survival.
  
  
  CONCLUSIONS
  While both inhibition and enhancement of autophagy by pharmacological intervention decreased lesion size and improved neurological scores, the enhancement with rapamycin showed a greater degree of improvement in outcomes as well as in survival. The protective action seen with chloroquine may be in part due to off-target effects on apoptosis separate from blocking lysosomal activity in autophagy. We conclude pharmacologic induction of autophagy is more advantageous than its blockade in physiologically-relevant permanent and slow reperfusion stroke models.
authors.affiliation: Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Buckley
authors.affiliation: The University of Virginia, School of Medicine, Charlottesville, VA, USA.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Hess
authors.affiliation: Department of Neurology, Georgia Regents University, Augusta, GA, USA ; Department of Medicine, Georgia Regents University, Augusta, GA, USA.
authors.forename: Irina Y
authors.initials: IY
authors.lastname: Sazonova
authors.affiliation: Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA.
authors.forename: Sudharsan
authors.initials: S
authors.lastname: Periyasamy-Thandavan
authors.affiliation: Department of Emergency Medicine, The University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: John R
authors.initials: JR
authors.lastname: Barrett
authors.affiliation: Department of Surgery, Carolinas Medical Center, Charlotte, NC, USA.
authors.forename: Russell
authors.initials: R
authors.lastname: Kirks
authors.affiliation: Medical College of Georgia, Georgia Regents University, Augusta, GA, USA.
authors.forename: Harrison
authors.initials: H
authors.lastname: Grace
authors.affiliation: Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA.
authors.forename: Galina
authors.initials: G
authors.lastname: Kondrikova
authors.affiliation: Department of Biostatistics and Epidemiology, Georgia Regents University, Augusta, GA, USA.
authors.forename: Maribeth H
authors.initials: MH
authors.lastname: Johnson
authors.affiliation: Department of Neurology, Georgia Regents University, Augusta, GA, USA.
authors.forename: David C
authors.initials: DC
authors.lastname: Hess
authors.affiliation: Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA.
authors.forename: Patricia V
authors.initials: PV
authors.lastname: Schoenlein
authors.affiliation: Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Neurology, Georgia Regents University, Augusta, GA, USA ; Medical Laboratory, Imaging & Radiologic Sciences, Georgia Regents University, Augusta, GA, USA ; Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, USA.
authors.forename: Md Nasrul
authors.initials: MN
authors.lastname: Hoda
authors.affiliation: Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA ; Department of Neurology, Georgia Regents University, Augusta, GA, USA.
authors.forename: William D
authors.initials: WD
authors.lastname: Hill
keywords: Autophagy; Cerebral ischemia; Chloroquine; Embolic stroke; Rapamycin