title: Long-term delivery enhances in vivo osteogenic efficacy of bone morphogenetic protein-2 compared to short-term delivery.
abstract: In this study, heparin-conjugated poly(l-lactide-co-glycolide) (PLGA) nanospheres (HCPNs) suspended in fibrin gel (group 1) were developed for a long-term delivery of BMP-2, and then used to address the hypothesis that a long-term delivery of BMP-2 would enhance ectopic bone formation compared to a short-term delivery at an equivalent dose. Fibrin gel containing normal PLGA nanospheres (group 2) was used for short-term delivery of BMP-2. The in vitro release of BMP-2 from group 1 was sustained for 4 weeks with no initial burst release. In contrast, 83% of BMP-2 loaded in group 2 was released only for the first 3 days. BMP-2 released from group 1 stimulated an increase in alkaline phosphatase (ALP) activity of osteoblasts for 9 days in vitro. In contrast, BMP-2 released from group 2 induced a transient increase in ALP activity for the first 5 days and a decrease thereafter. Importantly, group 1 induced bone formation to a much greater extent than did group 2, with 2.0-fold greater bone formation area and 3.5-fold greater calcium content, upon implantation into rat hind limb muscle. These results show that long-term delivery of BMP-2 enhances in vivo osteogenic efficacy of the protein compared to short-term delivery at an equivalent dose.
authors.affiliation: Department of Chemical Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Oju
authors.initials: O
authors.lastname: Jeon
authors.forename: Su Jin
authors.initials: SJ
authors.lastname: Song
authors.forename: Hee Seok
authors.initials: HS
authors.lastname: Yang
authors.forename: Suk-Ho
authors.initials: SH
authors.lastname: Bhang
authors.forename: Sun-Woong
authors.initials: SW
authors.lastname: Kang
authors.forename: Mi Ae
authors.initials: MA
authors.lastname: Sung
authors.forename: Jong Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Byung-Soo
authors.initials: BS
authors.lastname: Kim
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage*; D002478:Cells, Cultured; D003692:Delayed-Action Preparations / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*
chemical_list: C525719:Bmp2 protein, mouse; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D003692:Delayed-Action Preparations; D016212:Transforming Growth Factor beta