title: Percutaneous injection of augment injectable bone graft (rhPDGF-BB and β-tricalcium phosphate [β-TCP]/bovine type I collagen matrix) increases vertebral bone mineral density in geriatric female baboons.
abstract: BACKGROUND
  Recombinant human platelet-derived growth factor-BB (rhPDGF-BB) homodimer is a chemotactic, mitogenic, and angiogenic factor expressed by platelets. This biological triad is profoundly important in the bone regenerative cascade. Therefore, the expectation was that rhPDGF-BB locally administered to designated lumbar vertebrae in a soluble Type I bovine collagen/β-tricalcium phosphate (β-TCP) injectable paste would have an osteoanabolic effect.
  
  
  OBJECTIVE
  The study objective focused on safety and efficacy of the rhPDGF-BB and soluble Type I bovine collagen/β-TCP to increase bone density when injected directly into specific lumbar vertebral bodies in elderly (17- to 18-year-old) female baboons.
  
  
  METHODS
  The study was designed to determine whether vertebral bone mineral density (BMD) in aged female baboons could be increased by locally administering recombinant rhPDGF-BB combined in a soluble Type I bovine collagen/β-TCP paste formulation.
  
  
  METHODS
  A total of six baboons were divided equally into two groups. Group 1 received 1.0 mg/mL rhPDGF-BB in 20 mM sodium acetate plus soluble Type I bovine collagen/β-TCP. Group 2 was treated with 20 mM sodium acetate plus soluble Type I bovine collagen/β-TCP. Baboons in each group also received a sham surgery. Surgery was conducted using a percutaneous, fluoroscopically guided approach, and quantitative computed tomography (qCT) and radiographs were done at dedicated time periods. The qCT was used to determine volumetric BMD (vBMD). At euthanasia (36-week posttreatment), lumbar vertebrae were recovered and analyzed by qCT scans and histology. Funds were received to support this work from BioMimetic Therapeutics, Inc. The device that is the subject of this manuscript is not Food Drug Administration approved for this indication and is not commercially available in the United States.
  
  
  RESULTS
  The qCT and histopathological data suggested that vBMD and bone morphology increased significantly in the lumbar vertebrae treated with the rhPDGF-BB-containing composition.
  
  
  CONCLUSIONS
  Bone mineral density and bone morphology quality of lumbar vertebrae in aged female baboons were improved by direct injection of rhPDGF-BB in a soluble Type I bovine collagen/β-TCP paste. Throughout the course of the study, there were neither local nor systemic adverse effects.
authors.affiliation: BioMimetic Therapeutics, Inc., 389 Nichol Mill Lane, Franklin, TN 37067, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Perrien
authors.forename: Conan S
authors.initials: CS
authors.lastname: Young
authors.forename: Pedro P
authors.initials: PP
authors.lastname: Alvarez-Urena
authors.forename: David D
authors.initials: DD
authors.lastname: Dean
authors.forename: Samuel E
authors.initials: SE
authors.lastname: Lynch
authors.forename: Jeffrey O
authors.initials: JO
authors.lastname: Hollinger
mesh_terms: D000818:Animals; D000077214:Becaplermin; D015519:Bone Density / Q000187:drug effects*; D002130:Calcium Phosphates / Q000008:administration & dosage; D002417:Cattle; D024042:Collagen Type I / Q000008:administration & dosage; D004337:Drug Carriers / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000187:drug effects*; D008279:Magnetic Resonance Imaging; D010215:Papio; D020574:Proto-Oncogene Proteins c-sis / Q000008:administration & dosage*; D014057:Tomography, X-Ray Computed
chemical_list: D002130:Calcium Phosphates; D024042:Collagen Type I; D004337:Drug Carriers; D020574:Proto-Oncogene Proteins c-sis; C485817:beta-tricalcium phosphate; D000077214:Becaplermin