The synergistic effect of pulsed electromagnetic fields and demineralized bone matrix on the osteogenic differentiation of mesenchymal stem cells

Orthopaedic bone grafting continues to be a mainstay in the treatment of non unions and other difficult to heal bone defects. Tissue engineering strategies have focused on providing bone graft materials that are osteoconductive, osteoinductive and osteogenic in order to achieve optimal bone healing. Furthermore, electrical stimulation technologies such as pulsed electromagnetic fields (PEMF) have been used to enhance the effectiveness of bone graft materials. PEMP has been shown to have a synergistic effect with BMP-2 and it was hypothesized that PEMF would have the same effect with demineralized bone matrix (DBM). In the present study human mesenchymal stem cells (hMSCs) were seeded on DBM scaffolds in the presence of PEMF to determine if an increased osteogenic response could be induced. hMSCs were harvested from scaffolds at 5, 7, 14, and 21 days and osteogenic differentiation was assessed by testing for expression of alkaline phosphatase (ALP) and osteocalcin. Results demonstrated that PEMF was able to induce an increased osteogenic response throughout the 21 day culture. ALP and osteocalcin were significantly increased for PEMF treated groups at the earlier day 7 timepoint. DBM contains several osteoinductive growth factors and BMPs including BMP-2. The synergistic response seen between PEMF and DBM was most likely attributed to the osteoinductive factors found in DBM