title: CD34+ cells represent highly functional endothelial progenitor cells in murine bone marrow.
abstract: BACKGROUND
  Endothelial progenitor cells (EPCs) were shown to have angiogenic potential contributing to neovascularization. However, a clear definition of mouse EPCs by cell surface markers still remains elusive. We hypothesized that CD34 could be used for identification and isolation of functional EPCs from mouse bone marrow.
  
  
  RESULTS
  CD34(+) cells, c-Kit(+)/Sca-1(+)/Lin(-) (KSL) cells, c-Kit(+)/Lin(-) (KL) cells and Sca-1(+)/Lin(-) (SL) cells were isolated from mouse bone marrow mononuclear cells (BMMNCs) using fluorescent activated cell sorting. EPC colony forming capacity and differentiation capacity into endothelial lineage were examined in the cells. Although CD34(+) cells showed the lowest EPC colony forming activity, CD34(+) cells exhibited under endothelial culture conditions a more adherent phenotype compared with the others, demonstrating the highest mRNA expression levels of endothelial markers vWF, VE-cadherin, and Flk-1. Furthermore, a dramatic increase in immediate recruitment of cells to the myocardium following myocardial infarction and systemic cell injection was observed for CD34(+) cells comparing with others, which could be explained by the highest mRNA expression levels of key homing-related molecules Integrin β2 and CXCR4 in CD34(+) cells. Cell retention and incorporation into the vasculature of the ischemic myocardium was also markedly increased in the CD34(+) cell-injected group, giving a possible explanation for significant reduction in fibrosis area, significant increase in neovascularization and the best cardiac functional recovery in this group in comparison with the others.
  
  
  CONCLUSIONS
  These findings suggest that mouse CD34(+) cells may represent a functional EPC population in bone marrow, which could benefit the investigation of therapeutic EPC biology.
authors.affiliation: Group of Vascular Regeneration Research, Institute of Biomedical Research and Innovation/RIKEN Center for Developmental Biology, Kobe, Japan.
authors.forename: Junjie
authors.initials: J
authors.lastname: Yang
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ii
authors.forename: Naosuke
authors.initials: N
authors.lastname: Kamei
authors.forename: Cantas
authors.initials: C
authors.lastname: Alev
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kwon
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Kawamoto
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akimaru
authors.forename: Haruchika
authors.initials: H
authors.lastname: Masuda
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Sawa
authors.forename: Takayuki
authors.initials: T
authors.lastname: Asahara
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism*; D002478:Cells, Cultured; D004452:Echocardiography; D042783:Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism*
chemical_list: D018952:Antigens, CD34