Schematic overview outlining differentiation approaches currently used for cardiomyocyte differentiation from pluripotent stem cells. The embryoid body approach has, thus far, been the most utilized way to obtain beating cardiomyocytes from pluripotent stem cells and the formation of three-dimensional cell aggregates initiates and facilitates the differentiation process. Generally, cells are transferred to suspension cultures, or in order to obtain more stable and reproducible cell aggregates, the embryoid bodies are formed using the hanging-drop or the forced aggregation method. Using the END-2 approach, cardiomyocyte differentiation is triggered either by coculture of pluripotent stem cells, with END-2 cells or by embryoid body formation in suspension culture using END-2 conditioned medium. The depletion of serum and insulin has been shown to facilitate cardiogenesis in this approach, and it can be further enhanced by inhibiting p38 MAPK pathway by a specific inhibitor or by adding prostaglandin I2. In the guided differentiation approach, undifferentiated pluripotent stem cells are cultured under feeder cell-free conditions or in suspension culture after embryoid body formation. Cardiac differentiation is induced with various growth factors, such as BMP2, BMP4, Activin A, bFGF, and Wnt3a.
