Efficacy of hydroxyapatite ceramic as a carrier for recombinant human bone morphogenetic protein.

In this study, we investigated the efficacy of hydroxyapatite ceramic (HAP) as a carrier of bone morphogenetic protein (BMP) using porous HAP pellets artificially fabricated from limestone. After treatment with recombinant human BMP-2, the pellets were inserted beneath the cranial periosteum of rabbits, and the degree of osteogenesis was examined histologically. The degree of osteogenesis was also evaluated using image-analyzing procedures. Results showed that extensive bone formation had occurred around the pellets 3 weeks after insertion in the group that received pellets treated with recombinant human BMP alone as well as in the group that received recombinant human BMP in addition to type I collagen-treated HAP pellets. Subsequently, osteogenesis within the pellets slowly progressed over time, and by 9 weeks after insertion most of the pellet pores in both groups were filled with newly generated bone. The recombinant human BMP-collagen group, however, exhibited a significantly greater bone induction. These results indicated that if recombinant human BMP is used clinically in the future, artificially fabricated HAP would be a suitable carrier.