title: Differentiation and migration of Sca1+/CD31- cardiac side population cells in a murine myocardial ischemic model.
abstract: BACKGROUND
  Side population cells are a rare subset of cells found in the adult heart that are highly enriched for stem and progenitor cell activity. Recent studies have suggested that Sca1+/CD31- cardiac side population cells are capable of differentiation into cardiomyocytes in vitro. However, the response of these cells to myocardial injury remains unknown in vivo.
  
  
  METHODS
  Sca1+/CD31- cardiac side population cells were isolated from mouse (C57BL6/J) hearts by FACS. These cells were labeled and delivered via an intramyocardial injection into an infracted mouse heart. The differentiation potential of these cells was determined by immunohistochemistry two weeks later. We further tested the migration potential and the relationship of SDF-1alpha/CXCR4 to these cells.
  
  
  RESULTS
  The transplanted cells were found to express cardiomyocyte or endothelial cell specific markers. Furthermore, when these cells were transplanted into non-infarct myocardium after myocardial infarction, they were found in the damaged myocardium. Consistent with their homing property, we found that SDF-1alpha and CXCR4 were up-regulated in the damaged myocardium and on Sca1+/CD31- cardiac side population cells respectively following myocardial infarction. We also show that SDF-1alpha induced migration of Sca1+/CD31- cardiac side population cells in vitro.
  
  
  CONCLUSIONS
  Our results have suggested that Sca1+/CD31- cardiac side population cells are able to migrate into damaged myocardium from non-ischemic area of the heart and differentiate into both cardiomyocyte- and endothelial-like cells following acute ischemic injury. The SDF-1alpha/CXCR4 system might play an important role in the migration of these cells.
authors.affiliation: Center for Vascular Research, Department of Medicine and Hematology, St George Hospital, St George Clinical School, University of New South Wales, Sydney, 2052, Australia.
authors.forename: Simon X
authors.initials: SX
authors.lastname: Liang
authors.forename: Terence Y L
authors.initials: TY
authors.lastname: Tan
authors.forename: Leonie
authors.initials: L
authors.lastname: Gaudry
authors.forename: Beng
authors.initials: B
authors.lastname: Chong
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D054377:Chemokine CXCL12 / Q000378:metabolism; D002633:Chemotaxis / Q000502:physiology; D004195:Disease Models, Animal; D005260:Female; D005434:Flow Cytometry; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D017202:Myocardial Ischemia / Q000378:metabolism / Q000473:pathology* / Q000628:therapy*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
chemical_list: D000950:Antigens, Ly; C514936:CXCR4 protein, mouse; D054377:Chemokine CXCL12; C074650:Ly6a protein, mouse; D008565:Membrane Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D019718:Receptors, CXCR4