Synthetic octacalcium phosphate (OCP) is an effective scaffold to regenerate bone

Octacalcium phosphate (OCP) is supposed to be a precursor of biological apatite such as bone and tooth. We have examined experimentally whether synthetic octacalcium phosphate could be used as an effective scaffold to regenerate bone if implanted in vivo. We have fabricated the granules of the synthetic OCP. It was ascertained that the implanted OCP provided the core for nucleating multiple osteogenic sites and orthotopically induced bone formation and enhanced bone regeneration. OCP was resorbed by multinucleated giant cells that shared some ultrastructural characteristics with osteoclasts. The implanted OCP was more resorbable and replaced by newly formed bone than other calcium phosphate compounds, commonly used bone graft substitutes, such as synthetic hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). OCP sustained and delivered growth factors such as bone morphogenetic protein-2 (BMP-2) or transforming growth factor-β₁ (TGF-β₁) and the composites OCP with cytokine enhanced bone regeneration significantly. Therefore, the synthetic OCP would be an effective scaffold to bone regenerative therapy.