title: Evaluation of a β-calcium metaphosphate bone Graft containing bone morphogenetic protein-7 in rabbit maxillary defects.
abstract: BACKGROUND
  Calcium phosphate-based materials have been widely used as bone substitutes and more recently are being exploited together with growth factors as bone tissue engineering scaffolds regulating cell behavior. The aim of this study is to evaluate the in vitro and in vivo response to a newly developed calcium metaphosphate (CMP) bone graft, with and without bone-stimulating growth factor.
  
  
  METHODS
  Porous scaffolds of CMP were developed and extensively tested in vitro. Subsequently, CMP grafts with osteogenic protein-1 (OP-1) (test) and without OP-1 (control) were implanted into experimental rabbit maxillary bone defects. Animals were sacrificed at 2, 4, and 8 weeks, and samples were examined with microcomputed tomography (micro-CT) and processed for histomorphometric analysis.
  
  
  RESULTS
  At 8 weeks, the scaffolds containing OP-1 induced greater bone formation (P = 0.018) than CMP alone, based on histomorphometric evaluation (percentage bone area: test: 57.1 ± 5.6; control: 49.4 ± 7.7) and micro-CT analysis (percentage bone volume density: test: 63.46 ± 5.61; control: 51.20 ± 6.71). Thus, these data indicated that both test and control CMP grafts showed a good degree of bone formation. Furthermore, the CMP materials showed signs of resorption from 4 weeks, and no graft materials were observed at 8 weeks.
  
  
  CONCLUSIONS
  In vitro, the OP-1 loaded graft demonstrated a release profile and bioactivity over a 28-day period. In vivo testing confirmed enhanced bone formation of the OP-1 loaded graft after 8 weeks of healing.
authors.affiliation: Department of Biomaterials, Dental Institute, King's College London, London, UK.
authors.forename: Borvornwut
authors.initials: B
authors.lastname: Buranawat
authors.forename: Lucy
authors.initials: L
authors.lastname: Di Silvio
authors.forename: Sanjukta
authors.initials: S
authors.lastname: Deb
authors.forename: Ulf
authors.initials: U
authors.lastname: Nannmark
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
authors.forename: Richard M
authors.initials: RM
authors.lastname: Palmer
mesh_terms: D020341:Absorbable Implants; D000469:Alkaline Phosphatase / Q000032:analysis / Q000187:drug effects; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D055419:Bone Morphogenetic Protein 7 / Q000737:chemistry / Q000627:therapeutic use*; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004396:Coloring Agents; D004058:Diffusion; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008439:Maxillary Diseases / Q000473:pathology / Q000601:surgery*; D059630:Mesenchymal Stem Cells / Q000187:drug effects; D015675:Osteocalcin / Q000032:analysis / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D011817:Rabbits; D013778:Tetrazolium Salts; D013844:Thiazoles; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry*; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D055419:Bone Morphogenetic Protein 7; D002130:Calcium Phosphates; D004396:Coloring Agents; D013778:Tetrazolium Salts; D013844:Thiazoles; D015675:Osteocalcin; D000469:Alkaline Phosphatase; C022616:thiazolyl blue