A 3D prevascularized calcium phosphate cement scaffold for accelerated alveolar bone regeneration and angiogenesis in rats

OBJECTIVES: The objective of this study is to develop a load-bearing prevascularized construct by combining calcium phosphate cement (CPC) with cells within a three-dimensional (3D) hydrogel culture system, to accelerate the regeneration of alveolar bone defects. METHODS: A 3D co-culture system was established by encapsulating human periodontal ligament stem cells (hPDLSCs) and human umbilical vein endothelial cells (hUVECs) within a gelatin methacryloyl (GelMA) hydrogel on 3D-printed porous CPC scaffolds. The mechanical properties, pore structure and angiogenic potency were determined in vitro. In vivo performance was evaluated using a nude rat subcutaneous implantation model and a rat alveolar bone defect model. Four groups were tested: (1) Blank group (surgery-only group); (2) CPC+GelMA group (non-prevascularized group); (3) CPC+GelMA-cell group (prevascularized group)༛(4) Natural Periodontium group. RESULTS: The novel construct had good mechanical properties and biocompatibility. The 3D co-culture in GelMA successfully induced microvascular formation in vitro. Subcutaneous implantation in nude rats showed that the CPC+GelMA-cell group exhibited markedly greater angiogenic capacity than the CPC+GelMA group after 6 weeks, with a neovascular density 1.93-fold higher than that of the non-prevascularized group. Among all groups, the CPC+GelMA-cell group exhibited the strongest capacity for repairing rat alveolar bone defects. Compared to CPC+GelMA group, CPC+GelMA-cell group significant enhanced bone regeneration in rats by 1.23-1.37 folds, and increased vascularization by 2.65 folds (p<0.05). CONCLUSIONS: The novel 3D prevascularized CPC construct combined appropriate mechanical properties with great efficacy for alveolar bone regeneration and vascularization in vivo in an animal model.