title: Local delivery of granulocyte colony stimulating factor-mobilized CD34-positive progenitor cells using bioscaffold for modality of unhealing bone fracture.
abstract: We recently reported that i.v. transplantation of adult human circulating CD34+ cells, an endothelial/hematopoietic progenitor-enriched cell population, contributes to fracture healing through the enhancement of vasculogenesis and osteogenesis. However, the scarcity of CD34+ cells in the adult human is a critical issue for the future clinical application of this method. To overcome this issue, we assessed in vitro and in vivo capacity of granulocyte colony-stimulating factor-mobilized peripheral blood (GM-PB) human CD34+ cells for vasculogenesis and osteogenesis. First, we confirmed the differentiation capability of GM-PB CD34+ cells into osteoblasts in vitro. Second, local transplantation of GM-PB CD34+ cells on atelocollagen scaffold was performed in nude rats in a model of unhealing fractures. Immunostaining for human leukocyte antigen-ABC of tissue samples 1 week after fracture and cell therapy showed the superior incorporation after local transplantation compared with systemic infusion. Third, the effects of local transplantation of 10(5) (Hi), 10(4) (Mid), or 10(3) (Lo) doses of GM-PB CD34+ cells or phosphate-buffered saline (PBS) on fracture healing were compared. Extrinsic vasculogenic and osteogenic differentiation of GM-PB CD34+ cells, enhancement of the intrinsic angio-osteogenesis by recipient cells, augmentation of blood flow recovery at the fracture sites, and radiological and histological confirmation of fracture healing were observed only in the Hi and Mid groups but not in the Lo and PBS groups. These results strongly suggest that local transplantation of GM-PB CD34+ cells with atelocollagen scaffold is a feasible strategy for therapeutic vasculogenesis and osteogenesis needed for fracture healing. Disclosure of potential conflicts of interest is found at the end of this article.
authors.affiliation: Stem Cell Translational Research, Institute of Biomedical Research and Innovation/RIKEN Center for Developmental Biology, Kobe, Japan.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Mifune
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Kawamoto
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.forename: Taro
authors.initials: T
authors.lastname: Shoji
authors.forename: Hiroto
authors.initials: H
authors.lastname: Iwasaki
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kwon
authors.forename: Masahiko
authors.initials: M
authors.lastname: Miwa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Asahara
mesh_terms: D000328:Adult; D000818:Animals; D018952:Antigens, CD34 / Q000032:analysis*; D001854:Bone Marrow Cells / Q000166:cytology; D002196:Capillaries / Q000502:physiology; D002454:Cell Differentiation; D016207:Cytokines / Q000235:genetics; D005260:Female; D050723:Fractures, Bone / Q000150:complications* / Q000601:surgery*; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D019650:Hematopoietic Stem Cell Mobilization; D006801:Humans; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D010012:Osteogenesis; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects; D014183:Transplantation, Heterologous; D014945:Wound Healing
chemical_list: D018952:Antigens, CD34; D016207:Cytokines; D016179:Granulocyte Colony-Stimulating Factor; D012313:RNA