Figure 4.

Human Myocardial Graft Area is Significantly Increased 3 Months after Implantation with Notch Signaling

(A) Experimental timeline. Four days after ischemia/reperfusion injury, 2.5 × 10⁶ hESC-CMs were transplanted within the IgG control gel or the Delta-1 gel (control + hESC-CMs and Delta + hESC-CMs, respectively), with two additional gel-only control groups (control-no cells and Delta-no cells). (B and B′) Representative images of hESC-CM grafts identified by staining for β myosin heavy chain (βMHC, brown) with hematoxylin counterstain for control + hESC-CMs (B) and Delta + hESC-CMs (B′). Scale bars, 200 μm. (C) βMHC⁺ graft area is normalized to the LV area. There is a substantial increase in graft area with the Delta + hESC-CMs. (D) Proliferating hESC-CMs are identified by double-labeled βMHC⁺/BrdU⁺ cells, and quantification is shown here. There is a significant increase in Delta + hESC-CM proliferation. (E) Infarct area, quantified by the picrosirius red area, is normalized to the LV area. There is a modest, non-significant reduction in infarct size with Delta + hESC-CM treatment. (F) Anterior wall thickness is shown in mm. There is a modest, non-significant increase in anterior wall thickness in the Delta + hESC-CMs. For (C)–(F), ∗p < 0.05. Error bars indicate SEM. p-values were calculated for (C) and (D) using an unpaired t-test and for (E) and (F) using a one-way ANOVA followed by Sidak’s multiple comparison test comparing control-no cells versus Delta-no cells, control-no cells versus control + hESC-CMs, Delta-no cells versus Delta + hESC-CMs, and control + hESC-CMs versus Delta + hESC-CMs.