Osteogenic and angiogenic characterization of mandible and femur osteoblasts

Craniofacial autologous bone grafts offer superior outcomes to long bone grafts in the reconstruction of maxillofacial bone defects, but the mechanism responsible for this superiority has not yet been illustrated clearly. Osteoblasts play vital roles in bone development and regeneration. However, presently, only a few studies have compared the osteogenic ability of osteoblasts from craniofacial and long bones, and the results are contradictory. Additionally, the angiogenic characteristics of osteoblasts from these different bones remain unknown. We obtained osteoblasts from the rat mandible (MOBs) and femur (FOBs) to investigate their proliferative capacity and osteogenic potential, and using a co-culture system with human umbilical vein endothelial cells (HUVECs), we explored their angiogenic capabilities in vitro. FOBs exhibited higher alkaline phosphatase activity and increased matrix mineralization and expressed more osteogenic related marker genes, while MOBs proliferated at the highest rate and showed elevated expression of angiogenesis-related factors. Conditioned media from MOBs enhanced the expression of angiogenesis-related factors in HUVECs. Furthermore, the conditioned media generated from MOBs showed stronger promotion of proliferation, migration, and tube-like structure formation in HUVECs, suggesting that MOBs had a stronger pro-angiogenic effect on HUVECs than FOBs. Taken together, these results indicate that osteoblasts possess skeletal site-specific differences in osteogenic and angiogenic capabilities, and this might lead to a better understanding of the molecular impact of bone cells from different bone entities on maxillofacial bone reconstructions.