title: An injectable composite material containing bone morphogenetic protein-2 shortens the period of distraction osteogenesis in vivo.
abstract: To investigate new methods that can decrease the duration of bone transport (BT) distraction osteogenesis, we injected composite materials containing recombinant human bone morphogenetic protein-2 (BMP-2) and induced the generation of a callus bridge by rapid segmental transport (4 mm/day) in a rabbit bone defect model. The composite materials consisted of BMP-2 (0, 30, or 100 µg), β-tricalcium phosphate powder (βTCP, 100 mg/animal; particle size, <100 µm), and polyethylene glycol (PEG; 40 mg/animal). A paste of equivalent composition was percutaneously injected at the lengthening and the docking sites after surgery and after BT, respectively. The radiographic, mechanical, and histological examinations 12 weeks post-operative revealed that the generation of bridging callus in the presence and in the absence of BMP-2 was significantly different. The callus mass in the bone defect region was adequately and consistently developed in the presence of 100 µg of BMP (administered for 6 weeks), and the bones were consolidated in 12 weeks. Such an adequate callus formation was not observed in the control animals without BMP-2 treatment. The result of this experimental study suggests the potential application of BMP-2 in accelerating callus formation and in enabling rapid bone transporting, thereby shortening the treatment period for the repair of diaphyseal bone defects by distraction osteogenesis.
authors.affiliation: Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, 1-4-3 Asahi-machi, Abeno-ku, Osaka 545-8585, Japan. y-eguchi@med.osaka-cu.ac.jp
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Eguchi
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Wakitani
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Naka
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakamura
authors.forename: Kunio
authors.initials: K
authors.lastname: Takaoka
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000494:pharmacology*; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D002146:Bony Callus / Q000187:drug effects* / Q000502:physiology; D002130:Calcium Phosphates / Q000494:pharmacology*; D018483:Diaphyses / Q000000981:diagnostic imaging / Q000293:injuries / Q000503:physiopathology; D004339:Drug Compounding; D016503:Drug Delivery Systems / Q000379:methods; D008297:Male; D019857:Osteogenesis, Distraction / Q000379:methods*; D011817:Rabbits; D011859:Radiography; D011994:Recombinant Proteins / Q000494:pharmacology; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*
chemical_list: C525718:BMP2 protein, human; D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D002130:Calcium Phosphates; D011994:Recombinant Proteins; C485817:beta-tricalcium phosphate