Human grafts contain striated cardiomyocytes.

<p>Confocal fluorescent imaging of engrafted hESC-cardiomyocytes at 4 weeks indicate that all three engraftment methods produce grafts that have high cardiac purity, as indicated by a double-positive stain for α-actinin (red) and GFP (green) with nuclear DAPI (blue), in representative images of all grafts. All grafts demonstrate sarcomere striations at higher magnification (far right). Scar tissue appears as the dark band separating the patch graft and host myocardium (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0131446#pone.0131446.g003" target="_blank">Fig 3</a> for picrosirius red labeled scar, black arrowhead) and this extends to the edges of the patch (outside the field of view; not shown). White arrowhead in patch image points to GFP⁺/α-actinin^- non-cardiac cells. g, graft; s, scar, h, host. Scale bar = 500 μm and 50 μm (far right column).