Engineered bone tissue associated with vascularization utilizing a rotating wall vessel bioreactor.

Tissue-engineered bone has attracted much attention as an alternative material for bone grafting; however, implantable bone tissue of an appropriate size and shape for clinical use has not yet been developed due to a lack of vascularization, which results in necrosis of the seeded cells in vivo. This is the first report of bone tissue engineering associated with vascularization by co-culturing bone marrow mesenchymal stem cells (MSCs) with MSC-derived endothelial cells (ECs) within a porous scaffold using a rotating wall vessel (RWV) bioreactor. MSC-derived ECs were identified by immunofluorescence staining for von Willebrand factor (vWF) and by flow cytometry for CD31 expression. The tissue obtained was histochemically analyzed using toluidin blue, hematoxylin and eosin, anti-osteopontin antibody, anti-osteocalcin antibody, and tomato-lectin stain. Results showed that bone tissue containing vascular-like structures was generated. Three-dimensional culture condition created by medium flow in the RWV vessel and the interaction of MSCs with MSC-derived ECs might provide the cells an advantage in the construction of three-dimensional bone tissue with blood vessels.