Comparison of Decellularized Cow and Human Bone for Engineering Bone Grafts with Human Induced Pluripotent Stem Cells

Bone engineering makes it possible to grow unlimited amounts of viable tissue products for basic and applied research, and for clinical applications. A common trend in tissue engineering is the use of decellularized tissue matrices as scaffolding materials, which display structural, mechanical, and biological attributes typical of the native tissue. Due to the limited availability and high cost of human samples, decellularized tissue matrices are typically derived from animal sources. It is unclear, however, whether interspecies differences in tissue parameters will influence the quality of tissue grafts that are engineered using human stem cells. In this study, decellularized cow and human bone scaffolds were compared for engineering bone grafts using human induced pluripotent stem cell-derived mesodermal progenitor cells. After seeding, the cell-scaffold constructs were cultured for 5 weeks in osteogenic medium under dynamic conditions in perfusion bioreactors. The architectural and chemical properties of the scaffolds were studied using microscopic, spectroscopic, and thermogravimetric techniques, while cell behavior and formation of mineralized tissue were assessed using a combination of molecular assays, histological methods, and imaging technologies. The results show that while scaffolds derived from cow and human bone differ somewhat in architecture and composition, both equally support cell viability, tissue growth, and formation of a mineralized bone matrix. Taken together, the results suggest that scaffolds derived from cow bone represent a suitable and convenient alternative to engineer human bone grafts for various biomedical applications.