title: Timing of intra-arterial neural stem cell transplantation after hypoxia-ischemia influences cell engraftment, survival, and differentiation.
abstract: OBJECTIVE
  Intra-arterial neural stem cell (NSC) transplantation shows promise as a minimally invasive therapeutic option for stroke. We assessed the effect of timing of transplantation on cell engraftment, survival, and differentiation.
  
  
  METHODS
  Mouse NSCs transduced with a green fluorescent protein and renilla luciferase reporter gene were transplanted into animals 6 and 24 hours and 3, 7, and 14 days after hypoxia-ischemia (HI). Bioluminescent imaging was used to assess cell survival at 6 hours and 4 and 7 days after transplantation. Immunohistochemistry was used to assess NSC survival and phenotypic differentiation 1 month after transplantation. NSC receptor expression and brain gene expression were evaluated using real-time reverse transcription-quantitative polymerase chain reaction to elucidate mechanisms of cell migration. Boyden chamber assays were used to assess cell migratory potential in vitro.
  
  
  RESULTS
  NSC transplantation 3 days after HI resulted in significantly higher cell engraftment and survival at 7 and 30 days compared with all other groups (P<0.05). Early transplantation at 6 and 24 hours after HI resulted in significantly higher expression of glial fibrillary acidic protein (P=0.0140), whereas late transplantation at 7 and 14 days after HI resulted in higher expression of β-tubulin (P<0.0001). Corroborating the high cell engraftment 3 days after HI was robust expression of vascular cell adhesion molecule-1, CCL2, and CXCL12 in brain homogenates 3 days after HI.
  
  
  CONCLUSIONS
  Intra-arterial transplantation 3 days after HI results in the highest cell engraftment. Early transplantation of NSCs leads to greater differentiation into astrocytes, whereas transplantation at later time points leads to greater differentiation into neurons.
authors.affiliation: Department of Neurosurgery, Stanford University, 300 Pasteur Drive R211, Stanford, CA 94305-5327.  raphaelg@stanford.edu or guzmanr@uhbs.ch.
authors.forename: Sahar
authors.initials: S
authors.lastname: Rosenblum
authors.forename: Nancy
authors.initials: N
authors.lastname: Wang
authors.forename: Tenille N
authors.initials: TN
authors.lastname: Smith
authors.forename: Arjun V
authors.initials: AV
authors.lastname: Pendharkar
authors.forename: Joshua Y
authors.initials: JY
authors.lastname: Chua
authors.forename: Harjus
authors.initials: H
authors.lastname: Birk
authors.forename: Raphael
authors.initials: R
authors.lastname: Guzman
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D002454:Cell Differentiation; D002465:Cell Movement; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis; D006085:Graft Survival; D020925:Hypoxia-Ischemia, Brain / Q000378:metabolism / Q000628:therapy*; D008297:Male; D051379:Mice; D058953:Neural Stem Cells; D009474:Neurons / Q000378:metabolism; D033581:Stem Cell Transplantation; D013997:Time Factors; D014184:Transplantation, Homologous
chemical_list: D005904:Glial Fibrillary Acidic Protein