title: The bone regenerative effect of platelet-derived growth factor-BB delivered with a chitosan/tricalcium phosphate sponge carrier.
abstract: BACKGROUND
  In order to achieve optimal effects, growth factors including platelet-derived growth factor (PDGF) should be delivered with a biodegradable carrier that will release therapeutic concentrations over a sufficient length of time. The purpose of this study was to evaluate the bone regenerative effect of PDGF-BB delivered with a chitosan/tricalcium phosphate (TCP) sponge carrier in a rat calvarial defect model.
  
  
  METHODS
  The PDGF-BB-loaded chitosan/TCP sponge carrier was fabricated by freeze-drying a mixture of chitosan solution and TCP powder and soaking in a PDGF-BB solution. The release kinetics of PDGF-BB loaded onto the sponge were measured in vitro with 125I-labeled PDGF-BB. Chitosan/TCP sponges with and without PDGF-BB were implanted into 8 mm calvarial defects in rats. Rats were sacrificed at 2 and 4 weeks following implantation, and histologic and histomorphometrical examinations were performed.
  
  
  RESULTS
  In vitro evaluation demonstrated that an effective therapeutic concentration of PDGF-BB following a high initial burst release was maintained throughout the examination period. In the histologic examination, the chitosan/TCP sponge carrier promoted osseous healing of the rat calvarial defects as compared to controls. The addition of PDGF-BB to the carrier further enhanced bone regeneration. Evidence of the degraded sponge matrix was observed mingled within the newly formed bone without connective tissue encapsulation.
  
  
  CONCLUSIONS
  The results of this study support the use of chitosan/TCP sponges as a delivery system for growth factors and demonstrate that PDGF-BB loaded onto chitosan/TCP sponge carriers has an osteogenic effect on bone regeneration in vivo.
authors.affiliation: Department of Periodontology, College of Dentistry, Seoul National University, Korea.
authors.forename: Y M
authors.initials: YM
authors.lastname: Lee
authors.forename: Y J
authors.initials: YJ
authors.lastname: Park
authors.forename: S J
authors.initials: SJ
authors.lastname: Lee
authors.forename: Y
authors.initials: Y
authors.lastname: Ku
authors.forename: S B
authors.initials: SB
authors.lastname: Han
authors.forename: P R
authors.initials: PR
authors.lastname: Klokkevold
authors.forename: C P
authors.initials: CP
authors.lastname: Chung
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D000077214:Becaplermin; D001672:Biocompatible Materials; D001704:Biopolymers; D001847:Bone Diseases / Q000188:drug therapy / Q000473:pathology; D001861:Bone Regeneration / Q000187:drug effects*; D018786:Bone Substitutes; D002130:Calcium Phosphates; D002686:Chitin / Q000031:analogs & derivatives*; D048271:Chitosan; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D016503:Drug Delivery Systems; D007457:Iodine Radioisotopes; D008297:Male; D010012:Osteogenesis / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000008:administration & dosage / Q000627:therapeutic use*; D020574:Proto-Oncogene Proteins c-sis; D019275:Radiopharmaceuticals; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins; D012886:Skull / Q000187:drug effects / Q000473:pathology; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D001704:Biopolymers; D018786:Bone Substitutes; D002130:Calcium Phosphates; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D007457:Iodine Radioisotopes; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D019275:Radiopharmaceuticals; D011994:Recombinant Proteins; C485828:alpha-tricalcium phosphate; C485830:tetracalcium phosphate; D002686:Chitin; D000077214:Becaplermin; C485838:calcium phosphate, monobasic, anhydrous; D048271:Chitosan; C020243:calcium phosphate; C485829:calcium phosphate, dibasic, anhydrous