title: Poor osteoinductive potential of subcutaneous bone cement-induced membranes for tissue engineered bone.
abstract: BACKGROUND
  Large segmental bone defects remain a challenge for reconstructive surgeons. A two-stage repair strategy may offer a potential solution. Here, we sought to evaluate the osteoinductive potential of bone cement-induced membranes in an ectopic site.
  
  
  METHODS
  First, bone cements were inserted into the subcutaneous tissues of 16 rabbits to induce membrane formation. After 2, 4, 6 and 8 weeks, the induced membranes were harvested to assess their vascularization and osteoinductive potential. Next, bone cements were subcutaneously inserted into 12 rabbits for 4 weeks. These bone cements were then harvested from the newly formed membranes and replaced with granular porous β-TCP, with or without bone mesenchymal stem cells. New bone formation was then evaluated after 3, 6 and 9 weeks.
  
  
  RESULTS
  The highest level of blood vessel formation and bone morphogenetic protein-2 expression in the membranes were found at 4 weeks (p < 0.05). In addition, vascular endothelial growth factor concentration was highest after 2 weeks (p < 0.001), persisting until 8 weeks. However, the results showed little ectopic bone formation at these time points.
  
  
  CONCLUSIONS
  While bone cement-induced membranes appear to provide a suitable environment for bone formation, they fail to drive osteoinduction in non-osseous sites for the purposes of bone tissue engineering.
authors.affiliation: Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine , Shanghai , P.R. China and.
authors.forename: Fangchun
authors.initials: F
authors.lastname: Jin
authors.forename: Youzhuan
authors.initials: Y
authors.lastname: Xie
authors.forename: Nan
authors.initials: N
authors.lastname: Wang
authors.forename: Xinhua
authors.initials: X
authors.lastname: Qu
authors.forename: Jianxi
authors.initials: J
authors.lastname: Lu
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Hao
authors.forename: Kerong
authors.initials: K
authors.lastname: Dai
mesh_terms: D000818:Animals; D001843:Bone Cements; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis; D018786:Bone Substitutes; D001842:Bone and Bones / Q000098:blood supply / Q000166:cytology; D002130:Calcium Phosphates; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D016348:Osseointegration / Q000502:physiology*; D011817:Rabbits; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D001843:Bone Cements; D055396:Bone Morphogenetic Protein 2; D018786:Bone Substitutes; D002130:Calcium Phosphates; D042461:Vascular Endothelial Growth Factor A; C485817:beta-tricalcium phosphate