title: BMP-2 immobilized on nanocrystalline diamond-coated titanium screws; demonstration of osteoinductive properties in irradiated bone.
abstract: BACKGROUND
  Irradiation results in impaired bone healing. Thus, osteosynthesis procedures are afflicted with increased failure rates. To improve osseointegration bone morphogenetic protein-2 (BMP-2) immobilized on nanocrystalline diamond (NCD)-coated implant surfaces might be 1 solution.
  
  
  METHODS
  By 4 weeks after irradiation of pig's mandible with a dose of 60 Gy a fracture was accomplished. Osteosynthesis was performed either with titanium osteosynthesis screws or NCD-coated screws with immobilized BMP-2. Nonirradiated animals served as control. After 1, 2, 4, and 8 weeks screws were evaluated histologically. Bone biopsies were gained to extract mesenchymal stem or precursor cells (MSCs).
  
  
  RESULTS
  MSCs after irradiation demonstrated a behavior comparable to that of unirradiated cells. Consequently, immobilized BMP-2 resulted in an initial increased bone contact ratio (p = .014) but demonstrated no sustainable effect compared with osseointegration in nonirradiated bone (p = .08).
  
  
  CONCLUSIONS
  Immobilized BMP-2 demonstrates an osteoinductive effect in irradiated bone. MSCs as effector cells possess protective mechanisms to overcome the destructive effect of irradiation.
authors.affiliation: Department for Cranio-, Maxillofacial and Oral Surgery, Medical University Innsbruck, Innsbruck, Austria. frank.kloss@i-med.ac.at
authors.forename: Frank R
authors.initials: FR
authors.lastname: Kloss
authors.forename: Sarvpreet
authors.initials: S
authors.lastname: Singh
authors.forename: Oliver
authors.initials: O
authors.lastname: Hächl
authors.forename: Julia
authors.initials: J
authors.lastname: Rentenberger
authors.forename: Thomas
authors.initials: T
authors.lastname: Auberger
authors.forename: Anna
authors.initials: A
authors.lastname: Kraft
authors.forename: Guenther
authors.initials: G
authors.lastname: Klima
authors.forename: Thomas
authors.initials: T
authors.lastname: Mitterlechner
authors.forename: Doris
authors.initials: D
authors.lastname: Steinmüller-Nethl
authors.forename: Bernd
authors.initials: B
authors.lastname: Lethaus
authors.forename: Michael
authors.initials: M
authors.lastname: Rasse
authors.forename: Guenter
authors.initials: G
authors.lastname: Lepperdinger
authors.forename: Robert
authors.initials: R
authors.lastname: Gassner
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000494:pharmacology*; D001863:Bone Screws; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D018130:Diamond / Q000494:pharmacology; D004195:Disease Models, Animal; D005592:Fracture Fixation / Q000295:instrumentation / Q000379:methods; D017102:Fracture Healing / Q000502:physiology; D008334:Mandible / Q000473:pathology / Q000528:radiation effects* / Q000601:surgery; D008337:Mandibular Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D016348:Osseointegration / Q000187:drug effects*; D011829:Radiation Dosage; D011859:Radiography; D011897:Random Allocation; D012016:Reference Values; D012680:Sensitivity and Specificity; D013499:Surface Properties; D034421:Sus scrofa; D013552:Swine; D014025:Titanium / Q000494:pharmacology
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D018130:Diamond; D014025:Titanium