Prevascularization of biofunctional calcium phosphate cement for dental and craniofacial repairs

Calcium phosphate cement (CPC) is promising for dental and craniofacial repairs. Vascularization in bone tissue engineering constructs is currently a major challenge. The objectives of this study were to investigate the prevascularization of macroporous CPC via coculturing human umbilical vein endothelial cells (HUVEC) and human osteoblasts (HOB), and determine the effect of RGD in CPC on microcapillary formation for the first time.

Macroporous CPC scaffold was prepared using CPC powder, chitosan liquid and gas-foaming porogen. Chitosan was grafted with Arg-Gly-Asp (RGD) to biofunctionalize the CPC. HUVEC and HOB were cocultured on macroporous CPC-RGD and CPC control without RGD for up to 42d. The osteogenic and angiogenic differentiation, bone matrix mineral synthesis, and formation of microcapillary-like structures were measured.

RGD-grafting in CPC increased the gene expressions of osteogenic and angiogenic differentiation markers than those of CPC control without RGD. Cell-synthesized bone mineral content also increased on CPC-RGD, compared to CPC control (p<0.05). Immunostaining with endothelial marker showed that the amount of microcapillary-like structures on CPC scaffolds increased with time. At 42d, the cumulative vessel length for CPC-RGD scaffold was 1.69-fold that of CPC control. SEM examination confirmed the morphology of self-assembled microcapillary-like structures on CPC scaffolds.

HUVEC+HOB coculture on macroporous CPC scaffold successfully achieved prevascularization. RGD incorporation in CPC enhanced osteogenic differentiation, bone mineral synthesis, and microcapillary-like structure formation. The novel prevascularized CPC-RGD constructs are promising for dental, craniofacial and orthopedic applications.