title: Induction of bone formation by Escherichia coli-expressed recombinant human bone morphogenetic protein-2 using block-type macroporous biphasic calcium phosphate in orthotopic and ectopic rat models.
abstract: OBJECTIVE
  The potential of the Escherichia coli-expressed recombinant human bone morphogenetic protein-2 (ErhBMP-2) to support new bone formation/maturation using a block-type of macroporous biphasic calcium phosphate (bMBCP) carrier was evaluated in an orthotopic and ectopic rat model.
  
  
  METHODS
  Critical-size (Φ 8 mm) calvarial defects and subcutaneous pockets in 32 Sprague-Dawley rats received implants of rhBMP-2 (2.5 μg) in a bMBCP carrier or bMBCP alone (control). Implant sites were evaluated using histological and histometric analysis following 2- and 8-wk healing intervals (eight animals/group/interval).
  
  
  RESULTS
  ErhBMP-2/bMBCP supported significantly greater bone formation at 2 and 8 wk (10.8% and 25.4%, respectively) than the control at 2 and 8 wk (5.3% and 14.0%, respectively) in calvarial defects (p < 0.01). Bone formation was only observed for the ErhBMP-2/bMBCP ectopic sites and was significantly greater at 8 wk (7.5%) than at 2 wk (4.5%) (p < 0.01). Appositional and endochondral bone formation was usually associated with a significant increase in fatty marrow at 8 wk. The bMBCP carrier showed no evidence of bioresorption.
  
  
  CONCLUSIONS
  ErhBMP-2/bMBCP induced significant bone formation in both calvarial and ectopic sites. Further study appears to be required to evaluate the relevance of the bMBCP carrier.
authors.affiliation: Department of Periodontology, Research Institute for Periodontal Regeneration, College of Dentistry, Yonsei University, Seoul, South Korea.
authors.forename: J-C
authors.initials: JC
authors.lastname: Park
authors.forename: S-S
authors.initials: SS
authors.lastname: So
authors.forename: I-H
authors.initials: IH
authors.lastname: Jung
authors.forename: J-H
authors.initials: JH
authors.lastname: Yun
authors.forename: S-H
authors.initials: SH
authors.lastname: Choi
authors.forename: K-S
authors.initials: KS
authors.lastname: Cho
authors.forename: C-S
authors.initials: CS
authors.lastname: Kim
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis / Q000494:pharmacology*; D018786:Bone Substitutes; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D006882:Hydroxyapatites; D008297:Male; D023421:Models, Animal; D010012:Osteogenesis / Q000187:drug effects*; D016062:Porosity; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D012886:Skull / Q000601:surgery; D040521:Subcutaneous Tissue / Q000601:surgery; D054457:Tissue Scaffolds
chemical_list: D055396:Bone Morphogenetic Protein 2; D018786:Bone Substitutes; D006882:Hydroxyapatites; D011994:Recombinant Proteins; C074950:hydroxyapatite-beta tricalcium phosphate