Tissue Engineering and Regenerative Medicine

Electrical stimulation has been successfully used to treat bone defects clinically for many years. Recent in vitro studies have demonstrated that ES can change cell behavior such as migration, proliferation and differentiation. The goal of this project was to combine bone tissue engineering (TE) and electrical stimulation (ES) approaches in in vivo and in vitro experiments to determine its effectiveness and characterize the underlying mechanisms, respectively. In vitro experiments were performed in a customized six well ES culture chamber, in which we exposed adipose- (AT-MSC) and bone marrow- (BM-MSC) derived MSC to ES in 2D and 3D culture. Results showed that ES changed osteogenic gene expression patterns in both AT- and BM-MSC,and that these changes differed between the two groups. We found that ES increased BMP2 and TGF-ß1 expression in MSC suggesting calcium signaling as a potential mechanism. In in vivo experiments, a rat femur critical size defect (CSD) model was used and treated with AT-MSC seeded on calcium phosphate scaffold (β-TCP) material. Femurs from three groups of rats(40 per group; control=ß-TCP alone; sham=ß-TCP+AT-MSC; experimental=ES+ß-TCP+AT-MSC) were assessed at one and eight weeks post treatment by mean of histology, gene-expression and mechanical testing. The results of this ongoing in vivo experiment will be presented at the upcoming meeting. These initial findings may support the use of ES in TE applications which could potentially improve and expand their use in the clinical setting.