Regeneration of Bone Tissue in a Controlled in Vitro Environment with a Rotating Wall Vessel Bioreactor

To generate mature bone tissue in vitro, many types of cells in rabbit bone marrow aspirate were cultured within a rotating wall vessel (RWV) bioreactor. Bone marrow aspirate contains not only mesenchymal stem cells (MSCs) but also hematopoietic stem cells (HSCs), osteoblasts, osteocytes, osteoclasts, etc. Non-adherent cells in bone marrow aspirate were co-cultured with MSCs and MSC-derived endothelial cells under rotating condition with an RWV bioreactor. The engineered tissue was analyzed histochemically, and high-density tissue, a pre-bone-like structure containing osteoclast-like cells and thick vascular-like structures (approximately 50μm in diameter) were observed. Moreover, MSC-derived osteoblasts were co-cultured with these cells, and osteogenesis of cultured tissue was accelerated. Many types of cells and growth factors can repeatedly interact with each other in a rotating culture with an RWV bioreactor. These conditions could provide an excellent controlled environment for constructing bone tissue in vitro.