A pilot study to compare the activity of different bone morphogenetic protein bioimplants in vivo

摘要

Background: The challenge in developing safe clinically and cost-effective recombinant bone morphogenetic protein-2 (BMP) implants is reducing the amount of BMP required. Current implants using absorbable collagen sponges (ACS) produce a burst release of BMP and require high doses of BMP to be effective. The aim of this study was to investigate using Diphasic calcium phosphate (BCP) granules and calcium sulfate (CaS) granules in combination in P407 to deliver BMP. Methods: Different ratios of BCP to CaS granules were co-lyophilized with BMP. These were then combined with P407 gel with or without BMP. The implants were then placed in PBS buffer and the amount of BMP released evaluated by ELISA. Various BCP-CaS-P407 implants containing 40μg of BMP or ACS implants containing 80μg of BMP were implanted in muscle pouches of male CD-1 mice. At termination the amount of induced bone was quantified by microCT following correction for the presence of the implant and evaluated by histology. Statistical analysis was performed using ANOVA. Results: More bone was formed with implants containing CaS and/or BCP combined with poloxamer compared to ACS (p＜0.05) even though the contained less BMP. A greater ratio of CaS granules within the implant resulted in more bone formation. The location of BMP affected bone formation with more bone formed when BMP was divided between the granules and poloxamer. Conclusions: BMP implants containing BCP, CaS and P407 may require less BMP than ACS implants to be effective.