Figure 1. Stimulation of vasculogenesis/angiogenesis (A) and cardiomyogenesis (B) after application of static mechanical strain to ES cell-derived embryoid bodies. A) Embryoid bodies were treated on day 4 for 2 h with mechanical strain resulting in extension of the flexible membrane to 5, 10, 15, and 20%. On day 8 of cell culture the tissues were fixed and stained for PECAM-1 to analyze endothelial cell differentiation. The areas of PECAM-1-positive capillary-like structures were analyzed by the use of the image analysis software of the confocal setup. The images show representative PECAM-1 stainings in control (a), 5% (b), 10% (c), 15% (d), and 20% (e) strain-treated embryoid bodies. B) Embryoid bodies were treated on day 4 for 2 h with mechanical strain resulting in extension of the flexible membrane to 5, 10, and 20%. For investigation of the extension of the beating cardiac areas, tissues were fixed and stained against sarcomeric -actinin. The images show representative cardiac areas in control samples (a) as well as samples treated with 5% (b), 10% (c) and 20% (d) mechanical strain. The bar represents 200 µm. *P < 0.05, significantly different from the untreated control.