title: Controlled release by biodegradable hydrogels enhances the ectopic bone formation of bone morphogenetic protein.
abstract: The objective of this study is to develop a carrier for the controlled release of bone morphogenetic protein-2 (BMP-2) suitable for enhancement of the bone regeneration activity. Hydrogels with different water contents were prepared through glutaraldehyde crosslinking of gelatin with an isoelectric point of 9.0 under varied reaction conditions. Following subcutaneous implantation of the gelatin hydrogels incorporating 125I-labeled BMP-2 into the back of mice, the in vivo retention period of BMP-2 prolonged with a decrease in the water content of hydrogels used, although every time period was much longer than that of BMP-2 solution injection. Ectopic bone formation studies demonstrated that the alkaline phosphatase (ALP) activity and osteocalcin content around the implanted site of BMP-2-incorporated gelatin hydrogels were significantly high compared with those around the injected site of BMP-2 solution. The values became maximum for the gelatin hydrogel incorporating BMP-2 with a middle period of BMP-2 retention, while bone formation was histologically observed around the hydrogel incorporating BMP-2. The ALP activity was significantly higher than that of the collagen sponge incorporating BMP-2. We concluded that the controlled release technology of BMP-2 for a certain time period was essential to induce the potential activity for bone formation.
authors.affiliation: Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, 53 Kawara-cho Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tabata
mesh_terms: D000818:Animals; D001673:Biodegradation, Environmental; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics* / Q000494:pharmacology; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology; D003094:Collagen; D003692:Delayed-Action Preparations; D004343:Drug Implants; D005780:Gelatin; D006801:Humans; D020100:Hydrogels / Q000493:pharmacokinetics*; D007279:Injections, Subcutaneous; D007700:Kinetics; D051379:Mice; D010012:Osteogenesis / Q000187:drug effects; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology; D016212:Transforming Growth Factor beta
chemical_list: C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D003692:Delayed-Action Preparations; D004343:Drug Implants; D020100:Hydrogels; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D005780:Gelatin; D003094:Collagen