Electrical Field Stimulation with a Novel Platform: Effect on Cardiomyocyte Gene Expression but not on Orientation.

Electrical field stimulation has been shown to improve cardiac cell alignment and functional properties. In this study, neonatal rat cardiomyocytes were exposed to both long-term and short-term stimulation with the goal of investigating whether it is possible to achieve cell orientation and the maturation of cardiomyocytes with a novel, microelectrode array (MEA)-compatible electrical stimulation platform. Cells were viable after electrical stimulation, but no orientation or other morphological changes were observed. However, the electrode wires in MEA dishes affected the cell orientation. Cell contractions synchronized with pacing, but settled back to their original frequency in the absence of stimulation. The expression of genes encoding a gap junction protein connexin-43 (Cx-43), and contractile cardiac protein beta myosin heavy chain 7, was stronger in stimulated cells than in controls (p<0.05). In summary, the surface topography influenced to cardiomyocyte orientation, suggesting that the micro architecture of the biomaterials should be carefully designed for cell applications. However, as electrical stimulation and its duration affected gene expression of some main cardiac proteins, the stimulation system may prove useful to enhance the cardiac differentiation of stem cells.