title: Retention of endothelial progenitor cells in bone marrow in a murine model of endogenous tissue plasminogen activator (tPA) deficiency in response to critical limb ischemia.
abstract: BACKGROUND
  This study tested the hypothesis that tissue plasminogen activator (tPA) is crucial for regulating endothelial progenitor cell (EPC) mobilization from bone marrow to circulation in murine critical limb ischemia (CLI) by ligating the left femoral artery.
  
  
  METHODS
  Wild-type (C57BL/6) (n=40) mice were equally divided into group 1A (sham control), group 2A (CLI), group 3A [control-tPA (4.0 mg/kg)] and group 4A [CLI-tPA (intravenously at 3 h after CLI)]. Similarly, tPA knock-out (tPA(-/-)) mice (n=40) were equally divided into group 1B (sham control), group 2B (CLI), group 3B [control-tPA (4.0 mg/kg)], and group 4B (CLI-tPA).
  
  
  RESULTS
  The circulating levels of EPCs (C-kit/CD31+, Sca-1/KDR+, CXCR4/CD34+) were lower in groups 1B and 2B than in groups 1A and 2A, respectively (all p<0.01), and were reversed after tPA treatment (3B vs. 3A or 4B vs. 4A, p>0.05) at 6 h and 18 h post-CLI. Levels of these biomarkers decreased again 14 days after CLI in tPA(-/-) mice compared to those in wild-type between the respective groups (all p<0.01). Laser Doppler flowmetry showed a higher ratio of ischemic-to-normal blood flow in 2A than in 2B and in 4A than in 4B by day 14 after CLI (all p<0.05). Angiogenesis at protein (CXCR4, SDF-1α, VEGF) and cellular (CXCR4+, SDF-1α+, and CD31+ cells) levels was highest in animals with CLI-tPA, significantly higher in mice with CLI only than in sham controls for both wild-type and tPA(-/-) mice (p<0.01).
  
  
  CONCLUSIONS
  tPA played an essential role in augmenting circulating EPCs, angiogenesis, and blood flow in the ischemic limb in a murine model.
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Steve
authors.initials: S
authors.lastname: Leu
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Hung-I
authors.initials: HI
authors.lastname: Lu
authors.affiliation: Department of Emergency Medicine, E-Da Hospital, I-Shou University, Kaohsiung, Taiwan.
authors.forename: Cheuk-Kwan
authors.initials: CK
authors.lastname: Sun
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Jiunn-Jye
authors.initials: JJ
authors.lastname: Sheu
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yung-Lung
authors.initials: YL
authors.lastname: Chen
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Tzu-Hsien
authors.initials: TH
authors.lastname: Tsai
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Kuo-Ho
authors.initials: KH
authors.lastname: Yeh
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Han-Tan
authors.initials: HT
authors.lastname: Chai
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Sarah
authors.initials: S
authors.lastname: Chua
authors.affiliation: Institue of Molecular Biology, Academia Sinica, Taipei, Taiwan.
authors.forename: Ching-Yen
authors.initials: CY
authors.lastname: Tsai
authors.affiliation: Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan.
authors.forename: Hsueh-Wen
authors.initials: HW
authors.lastname: Chang
authors.affiliation: Division of Thoracic and Cardiovascular Surgery, Department of Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Fan-Yen
authors.initials: FY
authors.lastname: Lee
authors.affiliation: Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan; Division of Cardiology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, Taiwan. Electronic address: han.gung@msa.hinet.net.
authors.forename: Hon-Kan
authors.initials: HK
authors.lastname: Yip
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology*; D054377:Chemokine CXCL12 / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology*; D005263:Femoral Artery; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006614:Hindlimb / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D007511:Ischemia / Q000378:metabolism* / Q000473:pathology; D017078:Laser-Doppler Flowmetry; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000502:physiology; D010959:Tissue Plasminogen Activator / Q000172:deficiency / Q000235:genetics*
chemical_list: D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D010959:Tissue Plasminogen Activator; D020780:Matrix Metalloproteinase 9; C501830:Mmp9 protein, mouse
keywords: Critical limb ischemia; Endothelial progenitor cells; Knockout mice model; Tissue plasminogen activator