title: Development of a novel biomaterial, hydroxyapatite/collagen (HAp/Col) composite for medical use.
abstract: A hydroxyapatite/type I collagen (HAp/Col) composite, aligning hydroxyapatite nano-crystals along collagen molecules, has been synthesized. The biocompatibility, osteoconductivity and efficacy as an rhBMP-2 carrier of this novel biomaterial implanted in the weight-bearing site have been examined. The HAp/Col implants adsorbing 0 or 400 microg/ml of rhBMP-2 were implanted into bone defects of tibiae in 3 beagle dogs and fixed according to the Ilizarov method. As a control, bone defects of 20 mm remaining in 2 beagle dogs and the dogs were allowed to walk using a Ilizarov external skeletal fixator. The radiological and histological findings suggest that the implants induce bone remodeling units and are a superior carrier of rhBMP-2 due to the stimulation of early callus and new bone formation. As a next step, anterior fusion was carried out on 6 beagle dogs with the implants adsorbing 400 microg/ml of rhBMP-2, and 9 dogs with the implants without rhBMP-2. In 3 dogs of the rhBMP-treated group, as well as 6 dogs of the non-rhBMP-treated group, the implant was fixed with a poly-L-lactide plate. Histological and radiographical analysis suggest that enhancement of callus formation and bone bridging by rhBMP-treatment is effective to prevent collapse of the implant.
authors.affiliation: Division of Molecular Tissue Engineering, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8519, Japan. itoso.gene@cmn.tmd.ac.jp
authors.forename: Soichiro
authors.initials: S
authors.lastname: Itoh
authors.forename: Masanori
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Yosihisa
authors.initials: Y
authors.lastname: Koyama
authors.forename: Hiroko N
authors.initials: HN
authors.lastname: Matumoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Takakuda
authors.forename: Kenichi
authors.initials: K
authors.lastname: Shinomiya
authors.forename: Junzo
authors.initials: J
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage; D018786:Bone Substitutes; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D003094:Collagen / Q000737:chemistry*; D004285:Dogs; D016503:Drug Delivery Systems / Q000379:methods; D017886:Durapatite / Q000737:chemistry*; D017102:Fracture Healing / Q000187:drug effects / Q000502:physiology; D050723:Fractures, Bone / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology / Q000601:surgery*; D020007:Implants, Experimental; D008297:Male; D008420:Manufactured Materials; D008422:Materials Testing; D016348:Osseointegration / Q000187:drug effects / Q000502:physiology; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D011859:Radiography; D011884:Radius / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D013123:Spinal Fusion / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage; D016896:Treatment Outcome; D014457:Ulna / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology / Q000601:surgery
chemical_list: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D016212:Transforming Growth Factor beta; D003094:Collagen; D017886:Durapatite