title: A comparison of two biomaterial carriers for osteogenic protein-1 (BMP-7) in an ovine critical defect model.
abstract: Critical size defects in ovine tibiae, stabilised with intramedullary interlocking nails, were used to assess whether the addition of carboxymethylcellulose to the standard osteogenic protein-1 (OP-1/BMP-7) implant would affect the implant's efficacy for bone regeneration. The biomaterial carriers were a 'putty' carrier of carboxymethylcellulose and bovine-derived type-I collagen (OPP) or the standard with collagen alone (OPC). These two treatments were also compared to "ungrafted" negative controls. Efficacy of regeneration was determined using radiological, biomechanical and histological evaluations after four months of healing. The defects, filled with OPP and OPC, demonstrated radiodense material spanning the defect after one month of healing, with radiographic evidence of recorticalisation and remodelling by two months. The OPP and OPC treatment groups had equivalent structural and material properties that were significantly greater than those in the ungrafted controls. The structural properties of the OPP- and OPC-treated limbs were equivalent to those of the contralateral untreated limb (p > 0.05), yet material properties were inferior (p < 0.05). Histopathology revealed no residual inflammatory response to the biomaterial carriers or OP-1. The OPP- and OPC-treated animals had 60% to 85% lamellar bone within the defect, and less than 25% of the regenerate was composed of fibrous tissue. The defects in the untreated control animals contained less than 40% lamellar bone and more than 60% was fibrous tissue, creating full cortical thickness defects. In our studies carboxymethylcellulose did not adversely affect the capacity of the standard OP-1 implant for regenerating bone.
authors.affiliation: Department of Veterinary Clinical Sciences, University of Minnesota, 1352 Boyd Avenue, St. Paul, Minnesota 55108, USA. pluha006@umn.edu
authors.forename: G E
authors.initials: GE
authors.lastname: Pluhar
authors.forename: A S
authors.initials: AS
authors.lastname: Turner
authors.forename: A R
authors.initials: AR
authors.lastname: Pierce
authors.forename: C A
authors.initials: CA
authors.lastname: Toth
authors.forename: D L
authors.initials: DL
authors.lastname: Wheeler
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000008:administration & dosage*; D001696:Biomechanical Phenomena; D001847:Bone Diseases / Q000188:drug therapy / Q000473:pathology / Q000503:physiopathology; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D001861:Bone Regeneration / Q000187:drug effects*; D002266:Carboxymethylcellulose Sodium / Q000008:administration & dosage*; D024042:Collagen Type I / Q000008:administration & dosage; D004195:Disease Models, Animal; D004337:Drug Carriers; D004343:Drug Implants; D005260:Female; D011859:Radiography; D011994:Recombinant Proteins / Q000008:administration & dosage; D012756:Sheep; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*
chemical_list: D001672:Biocompatible Materials; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D024042:Collagen Type I; D004337:Drug Carriers; D004343:Drug Implants; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D002266:Carboxymethylcellulose Sodium