Three-dimensional bone formation including vascular networks derived from dental pulp stem cells in vitro.

The regeneration of bone tissue is an active area of research, and future clinical applications are expected. Here, to establish new bone graft materials and an experimental bone tissue model, we generated united compact and spongy bone tissues containing vascular networks from human dental pulp stem cells in vitro. We applied the cell bead and cell sheet methods to construct three-dimensional bone tissue, which was cultured using a circumfusion apparatus for 30 days. Using micro-computed tomography, we assessed structural differences between compact and spongy bone. Histological examinations revealed the presence of bone lacunae containing osteocytes, Haversian canal-like structures, and extensive vascularization. Furthermore, tartrate-resistant acid phosphatase (TRAP) staining-positive osteoclast-like cells were also observed. Thus, the bone tissue generated using this method closely resembles native bone tissue and may possess bone remodeling ability. We successfully generated bone tissue containing blood vessel networks in vitro using this method. The generated bone tissue will likely be highly applicable to medical care, the study of osteogenesis, drug-screening assays, and drug development for bone tissue.