Pro-Osteogenic Potential of ECM from BMP2 Over-Expressing Cells

Hypothesis: The ECM created by BMP2 over-expressing cells will have superior pro-osteogenic potential compared to ECM from HMSC. Introduction: Dental implant therapy is a commonly used modality to replace missing teeth. In many instances, however, insufficient alveolar bone volume is present and guided bone regeneration is required either prior to or at the time of implant placement to obtain sufficient bone volume. To date, many tissue engineering approaches have been used to increase both the rate and quality of bone remodeling. This study was undertaken to compare the pro-osteogenic capacity of extracellular matrix (ECM) created by BMP2 over-expressing stem cells in comparison to ECM of regular human mesenchymal stem cells (HMSC). Methods: ECM from BMP2 over-expressing cells and control HMSC were generated in 6-well plates. A control group consisting of no ECM was cultured as well. Data for cell proliferation was obtained at days 1,4,7, and 10. Cell differentiation at 7 days and 14 days was analyzed via quantitative PCR using osteogenic markers for each of the three groups. In addition, the ECM from BMP2 over-expressing cells and HMSC were characterized by immunohistochemical analysis. Results: For cell proliferation, only modest differences were noted between the three groups. At Day 7, both the BMP2 ECM and HMSC ECM groups showed greater cell proliferation compared to the control group. With respect to cell differentiation, at 14 days several pro-osteogenic, angiogenic growth factors and transcription factors were expressed at a higher level in the HMSCs cultured on BMP2 ECM with respect to the controls. Conclusion: The ECM from BMP2 over-expressing cells appears capable of increasing cell proliferation and inducing pro-osteogenic cell differentiation compared to control HMSCs and tissue culture plastic. Further research is needed to evaluate the effects on 3D scaffolds, such as collagen and bone graft particulates.