title: Capillary remodeling and collateral growth without angiogenesis after unilateral common carotid artery occlusion in mice.
abstract: OBJECTIVE
  To clarify the mechanisms of blood flow restoration after major artery occlusion, we presented first dynamic changes in cortical vessel morphology observed through a cranial window in mice after unilateral common carotid artery (CCA) occlusion.
  
  
  METHODS
  The density and diameter of capillaries, as well as diameters of pial arteries, were measured by confocal laser-scanning microscopy and fluorescent microscopy, respectively. Possible angiogenesis was evaluated by detecting any outgrowth of endothelial cells from pre-existing vessels or intussusception in Tie2-GFP mice.
  
  
  RESULTS
  Immediately after unilateral CCA occlusion, cerebral blood flow (CBF) index, the reciprocal of mean transit time, reduced significantly and returned to the previous level after 14 days. Repeated observation of the cortical vessels did not reveal any angiogenesis, whereas the cortical capillary diameter increased by 74% after 14 days. The anterior cerebral artery (ACA) and collateral vessels connecting ACA and middle cerebral artery also dilated significantly. The capillary dilatation to the size of arteriole in the settings of collateral growth and CBF restoration suggested capillary remodeling.
  
  
  CONCLUSIONS
  Our results indicate that capillary remodeling, pial artery dilatation and collateral growth without angiogenesis are sufficient mechanisms to restore normal cerebral blood flow after unilateral CCA occlusion.
authors.affiliation: Department of Neurology, School of Medicine, Keio University, Tokyo, Japan.
authors.forename: Huailian
authors.initials: H
authors.lastname: Guo
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Itoh
authors.forename: Haruki
authors.initials: H
authors.lastname: Toriumi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yamada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Tomita
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Hoshino
authors.forename: Norihiro
authors.initials: N
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D001157:Arterial Occlusive Diseases / Q000473:pathology / Q000503:physiopathology*; D002196:Capillaries / Q000473:pathology*; D017536:Carotid Artery, Common; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D004108:Dilatation, Pathologic; D051379:Mice; D008853:Microscopy; D009389:Neovascularization, Pathologic