title: Dual-purpose bone grafts improve healing and reduce infection.
abstract: OBJECTIVE
  To determine if a dual-purpose bone graft can regenerate bone and reduce infection in highly contaminated bone critical size defects in rats.
  
  
  METHODS
  Biodegradable polyurethane (PUR) scaffolds were loaded with recombinant human bone morphogenetic protein-2 (BMP-2) and vancomycin (Vanc). The release kinetics of the BMP-2 were tuned to take advantage of its mechanism of action (ie, an initial burst to recruit cells and sustained release to induce differentiation of the migrating cells). The Vanc release kinetics were designed to protect the graft from contamination until it is vascularized by having a burst for a week and remaining well over the minimum inhibitory concentration for Staphylococcus aureus for 2 months. The bone regeneration and infection reduction capability of these dual-purpose grafts (PUR+Vanc+BMP-2) were compared with collagen sponges loaded with BMP-2 (collagen+BMP-2) and PUR+BMP-2 in infected critical size rat femoral segmental defects.
  
  
  RESULTS
  The dual-delivery approach resulted in substantially more new bone formation and a modest improvement in infection than PUR+BMP-2 and collagen+BMP-2 treatments.
  
  
  CONCLUSIONS
  The PUR bone graft is injectable, provides a more sustained release of BMP-2 than the collagen sponge, and can release antibiotics for more than 8 weeks. Thus, the dual-delivery approach may improve patient outcomes of open fractures by protecting the osteoinductive graft from colonization until vascularization occurs. In addition, the more optimal release kinetics of BMP-2 may reduce nonunions and the amount of growth factor required.
authors: Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, USA.
authors: Scott A
authors: SA
authors: Guelcher
authors: Kate V
authors: KV
authors: Brown
authors: Bing
authors: B
authors: Li
authors: Teja
authors: T
authors: Guda
authors: Baek-Hee
authors: BH
authors: Lee
authors: Joseph C
authors: JC
authors: Wenke
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D016025:Bone Transplantation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods*; D003131:Combined Modality Therapy; D003692:Delayed-Action Preparations / Q000008:administration & dosage; D005264:Femoral Fractures / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D017102:Fracture Healing / Q000187:drug effects; D048091:Guided Tissue Regeneration / Q000009:adverse effects / Q000379:methods*; D010000:Osteitis / Q000175:diagnosis / Q000517:prevention & control*; D051381:Rats; D054457:Tissue Scaffolds; D016896:Treatment Outcome; D014640:Vancomycin / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D003692:Delayed-Action Preparations; D014640:Vancomycin