title: Experimental study of vascularized tissue-engineered bone grafts.
abstract: BACKGROUND
  Vascularized bone grafting has become a useful method for treatment of large bone defects and infected nonunions that lack adequate blood supply. This method has disadvantages, however, such as donor-site complications. To overcome these disadvantages, the authors developed a new method for creating vascularized tissue-engineered bone grafts in an experimental model.
  
  
  METHODS
  Fisher rat bone marrow mesenchymal stem cells were cultured for 2 weeks in fully opened, interconnected, porous hydroxyapatite ceramic. The composites of mesenchymal stem cells and hydroxyapatite were implanted in the medial calf region together with the saphenous vascular bundle in syngeneic rats. Two weeks after implantation, the vascular pedicle with the implants was exposed and covered with silicone rubber to prevent vascular invasion through surrounding tissues (vascularized mesenchymal stem cell/hydroxyapatite implants). In addition, nonvascularized mesenchymal stem cell/hydroxyapatite implants were created with a ligated vascular pedicle. Implants of vascularized hydroxyapatite alone were prepared as a control. All implants were retrieved 4 weeks after surgery.
  
  
  RESULTS
  Histologically, de novo bone formations were observed in the vascularized implants. This was in contrast with only necrotic tissue observed in the nonvascularized implants. Bone formation was not observed entirely in the vascularized hydroxyapatite-alone implants. For biochemical analysis, alkaline phosphatase activity and osteocalcin content of the vascularized mesenchymal stem cell/hydroxyapatite implants were significantly higher than those of the nonvascularized mesenchymal stem cell/hydroxyapatite and vascularized hydroxyapatite-alone implants.
  
  
  CONCLUSIONS
  The results of this study indicated that the vascularized tissue-engineered bone grafts could be transferred as free vascularized grafts to lesions that lack adequate blood supply.
authors.affiliation: Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan. kkenji@naramed-u.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Kawamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yajima
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohgushi
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tomita
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kobata
authors.forename: Koji
authors.initials: K
authors.lastname: Shigematsu
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Takakura
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D016025:Bone Transplantation / Q000379:methods*; D002478:Cells, Cultured; D017886:Durapatite; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D008866:Microsurgery; D051381:Rats; D011916:Rats, Inbred F344; D023822:Tissue Engineering; D014182:Transplantation, Autologous
chemical_list: D017886:Durapatite; D000469:Alkaline Phosphatase