In vitro hBM-MSCs characterization and differentiation on the scaffold for bone regenerative medicine

New methods have been developed to achieve tissue regeneration of complex bone defects and restore the healing process, which is impaired by several factors; in this contest bone tissue engineering (BTE) is an alternative to autologous gold-standard treatment. BTE combines biocompatible scaffolds with morphogenic signals and stem cells, to create a biomimetic microenvironment that provides mechanical and chemical cues. In this project, we studied all key elements of BTE and evaluated Mesenchymal stem cells (MSC) with xenograft-derived bone scaffold (SmartBone® SBN) and rhBMP-2 as growth factor. MSCs are an attractive source of stem cells because of their ability to undergo self-renewal, multi-lineage differentiation (including into osteoblast lineage) and paracrine actions. Here, we reported our experience in MSCs expansion protocols and proposed human Platelet-Rich Plasma (PRP) as a substitute for Fetal Bovine Serum (FBS) in media supplementation. After MSCs isolation from patients bone marrow, we expanded the cells in media supplemented with FBS or PRP, obtained from a venous blood sample of the same patients. Our final outcome indicated that PRP is a good cell culture supplement, since it did not impact MSCs marker expression and differentiation potential. In the second part of the project, we seeded hBM-MSC on xenograft-derived bone scaffold and cultured them in osteogenic and MSC expansion media to investigate the effects of the composition of support on cell metabolic activity and osteogenic differentiation. The scaffold retains biological properties and resembles the human bone structure. We demonstrated its biocompatibility supporting both BM-MSCs proliferation and differentiation. Moreover, new collagen deposition was revealed in both analyzed conditions, suggesting a good osteoconductivity of the scaffold. Finally, we aimed to modify the scaffold by the addition of rhBMP-2 to improve its osteogenic abilities and enhance new bone formation. Future experiments will assess the impact of BMP2 modification on cellular differentiation.