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Ectopic bone formation using osteogenic protein-1 carried by a solution precipitated hydroxyapatite.

Renwen Zhang·Dazhong Xu·Tracy Landeryou·Carol Toth·Nena Dimaano·Jenny Berry·Julie Evans·Monica Hawkins
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Abstract

Solution precipitation of calcium and phosphate is a technique to generate hydroxyapatite [Peri-Apatitetrade mark (PA), Stryker Orthopaedics, Mahwah, NJ] on metal substrate. This study was carried out to determine the capacity of PA to adsorb osteogenic protein-1 (OP-1) and the time course of release, and to determine the osteoinductive activity of OP-1. The adsorption and release studies were conducted with (125)I-labeled OP-1- and PA-coated titanium alloy disks. The results indicate that the adsorption of OP-1 on the PA-coated disks is linear with the concentration of OP-1 up to 5 mg/mL. There is an initial release of 75% to 80% of adsorbed OP-1 within the first hour, and 92% of OP-1 is released in 3 days. The osteoinductive activity of OP-1 was determined in the rat intramuscular ectopic bone formation assay. A total of 24 titanium alloy disks were evenly divided into 3 groups with different treatments for implantation, plain disks (group A), disks coated with PA (group B), and disks coated with PA plus 40 microg OP-1 (group C). Osteogenic protein-1, 40 microg in solution, was injected into the muscle pouch in animals of group D (n = 8). The rats were sacrificed 3 weeks postoperatively and the implants were retrieved. Ectopic bone formation was evaluated with radiography and histology. Results demonstrated that OP-1 induced ectopic bone in all the animals of group C and group D. The titanium alloy disks were surrounded by trabecular bone and marrow tissue. None of the animals of group A or group B showed any evidence of osteoinduction. Our findings indicate that PA can deliver OP-1 directly to titanium alloy implants and maintain the osteoinductive activity of OP-1.

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AbsorptionAnimalsBone Morphogenetic Protein 7Bone Morphogenetic ProteinsBone and BonesHydroxyapatitesMaleOsteogenesisRatsRats, Long-EvansSolutionsTime FactorsTitaniumTransforming Growth Factor betaJournal Article

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Renwen Zhang, Dazhong Xu, Tracy Landeryou, Carol Toth, Nena Dimaano, Jenny Berry, Julie Evans, Monica Hawkins. 2004-12-01. Ectopic bone formation using osteogenic protein-1 carried by a solution precipitated hydroxyapatite.. https://doi.org/10.1002/jbm.a.30151

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