Orthotopic bone formation by implantation of apatite-coated poly(lactide-co-glycolide)/hydroxyapatite composite particulates and bone morphogenetic protein-2

J Biomed Mater Res A. 2008 Oct;87(1):245-53. doi: 10.1002/jbm.a.31782.

Abstract

Bone morphogenetic proteins (BMPs) are the most potent osteoinductive growth factors. However, a delivery system is essential to take advantage of the osteoinductive effect of BMPs. In the present study, we tested the suitability of apatite-coated poly(D,L-lactide-co-glycolide)/nanohydroxyapatite (PLGA/HA) particulates as carriers for the controlled release of BMP-2. The release of BMP-2 from apatite-coated PLGA/HA particulates was sustained for at least 4 weeks in vitro. A delivery system of apatite-coated PLGA/HA particulates suspended in fibrin gel further slowed the BMP-2 release rate. In vivo implantation of either Fibrin gel + BMP-2 or Fibrin gel + apatite-coated PLGA/HA particulates showed enhanced new bone formation in critical-sized calvarial defects of rats 8 weeks after implantation, compared to implantation of fibrin gel only. Importantly, new bone formation was much higher in the defects treated with BMP-2 delivery using apatite-coated PLGA/HA particulates in fibrin gel (Fibrin gel + PLGA/HA + BMP-2 group) than in the defects treated either with apatite-coated PLGA/HA particulates in fibrin gel (Fibrin gel + BMP-2 group) or with BMP-2 delivery using fibrin gel alone (Fibrin gel + BMP-2 group). BMP-2 and osteoinductive HA had an additive effect on orthotopic bone formation. In conclusion, the apatite-coated PLGA/HA particulates showed good results as carriers for BMP-2. The BMP-2 delivery system showed high osteogenic capability in a rat calvarial bone defect model. The local and sustained delivery system for BMP-2 developed in this study may be useful as a carrier for BMP-2 and would enhance bone regeneration efficacy for the treatment of large bone defects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Body Fluids
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins / pharmacology*
  • Calcification, Physiologic / drug effects
  • Coated Materials, Biocompatible / pharmacology
  • Drug Carriers / pharmacology
  • Drug Implants / pharmacology
  • Durapatite / pharmacology*
  • Fibrin / pharmacology
  • Gels
  • Lactic Acid / pharmacology*
  • Male
  • Osteogenesis / drug effects*
  • Polyglycolic Acid / pharmacology*
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Radiography
  • Rats
  • Rats, Sprague-Dawley
  • Skull / anatomy & histology
  • Skull / diagnostic imaging
  • Transforming Growth Factor beta / pharmacology*

Substances

  • Bmp2 protein, rat
  • Bone Morphogenetic Protein 2
  • Bone Morphogenetic Proteins
  • Coated Materials, Biocompatible
  • Drug Carriers
  • Drug Implants
  • Gels
  • Transforming Growth Factor beta
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Polyglycolic Acid
  • Lactic Acid
  • Fibrin
  • Durapatite