title: Local transplantation of ex vivo expanded bone marrow-derived CD34-positive cells accelerates fracture healing.
abstract: Transplantation of bone marrow (BM) CD34(+) cells, an endothelial/hematopoietic progenitor-enriched cell population, has shown therapeutic efficiency in the treatment of ischemic diseases enhancing neovascularization. However, the number of CD34(+) cells obtained from  bone marrow is not sufficient for routine clinical application. To overcome this issue, we developed a more efficient and clinically applicable CD34(+) cell expansion method. Seven-day ex vivo expansion culture of BM CD34(+) cells with a cocktail of five growth factors containing  VEGF, SCF, IL-6, Flt-3 ligand, and TPO resulted in reproducible more than 20-fold increase in cell number. The favorable effect of the local transplantation of culture expanded (cEx)-BM CD34(+) cells on rat unhealing fractures was equivalent or higher than that of nonexpanded (fresh)  BM CD34(+) cells exhibiting sufficient therapeutic outcome with frequent vasculogenic/osteogenic differentiation of transplanted cEx-BM CD34(+) cells and fresh BM CD34(+) cells as well as intrinsic enhancement of angiogenesis/osteogenesis at the treated fracture  sites. Specifically, cEx-BM CD34(+) cell treatment demonstrated the best blood flow recovery at fracture sites compared with the nonexpanded BM CD34(+) cells. In vitro, cEx-BM CD34(+) cells showed higher colony/tube-forming capacity than nonexpanded BM CD34(+)  cells. Both cells demonstrated differentiation potential into osteoblasts. Since fresh BM CD34(+) cells can be easily collected from fracture sites at the time of primary operation and stored for future use, autologous cEx-BM CD34(+) cell transplantation would be not only  a simple but also a promising therapeutic strategy for unhealing fractures in the field of orthopedic trauma surgery.
authors.affiliation: Group of Vascular Regeneration, Institute of Biomedical Research and Innovation, Kobe, Hyogo, Japan.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kawakami
authors.forename: Masaaki
authors.initials: M
authors.lastname: Ii
authors.forename: Cantas
authors.initials: C
authors.lastname: Alev
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Kawamoto
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kuroda
authors.forename: Taro
authors.initials: T
authors.lastname: Shoji
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Fukui
authors.forename: Haruchika
authors.initials: H
authors.lastname: Masuda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Akimaru
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Mifune
authors.forename: Tomoya
authors.initials: T
authors.lastname: Kuroda
authors.forename: Miki
authors.initials: M
authors.lastname: Horii
authors.forename: Ayumi
authors.initials: A
authors.lastname: Yokoyama
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kurosaka
authors.forename: Takayuki
authors.initials: T
authors.lastname: Asahara
mesh_terms: D000818:Animals; D018952:Antigens, CD34 / Q000378:metabolism*; D001783:Blood Flow Velocity; D001854:Bone Marrow Cells / Q000166:cytology*; D001842:Bone and Bones / Q000098:blood supply; D002454:Cell Differentiation; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000473:pathology / Q000628:therapy*; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D008297:Male; D009389:Neovascularization, Pathologic; D010012:Osteogenesis; D051381:Rats; D011923:Rats, Nude; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D018952:Antigens, CD34; D036341:Intercellular Signaling Peptides and Proteins