Fig. 4.

Heart failure and lineage commitment of CSCs. (A-C) Myocyte progenitors (A) express c-kit (green) and the myocyte transcription factor MEF2C (yellow dots); myocyte precursors (B) express c-kit (green), MEF2C (yellow dots) and have a thin layer of cytoplasm positive for α-sarcomeric actin (red). (C) Small developing myocytes (α-sarcomeric actin, red) express MEF2C (yellow dots) and have lost the stem cell surface antigen. Connexin 43 is detected between some of these maturing cells (green, arrows). (D) Myocyte progenitors and precursors. ^*, P < 0.05 vs. controls (C); ^**, P < 0.05 between the border and remote myocardium in acute MI; †, P < 0.05 between acute and chronic MI. Shown are acute infarcts (A and C) and a chronic infarct (B). (Scale bars: 10 μm.)