Differentiation of murine induced pluripotent stem cells (iPSCs) into cardiomyocytes (CMs). (A) Schematic representation of the experimental protocol. (B) Representative images of embryoid bodies (EBs) composed of a mixed cell population containing areas of GFP-expressing CMs on differentiation day 9. Purified cardiac clusters were generated by selection with puromycin until day 16. (C) Flow cytometry analysis of GFP-positive iPS-CMs after trypsinization of puromycin-selected cardiac clusters on day 16. (D) α-Actinin (red) staining of puromycin-selected CMs (green) on differentiation day 21. (E) Effect of hypoxia and glucose/serum deprivation on poly-caspase activity in iPS-CMs. The baseline level of poly-caspase active in iPS-CMs was determined in normoxia and full medium. *P ≤ 0.05, versus normoxia for individual datasets (Bonferroni test); **P < 0.001, overall by analysis of variance. FBS, fetal bovine serum; GFP, green fluorescent protein; Glu, glucose; PI, propidium iodide.