Introduction:
Both human embryonic stem cell-derived cardiomyocytes (ESC-CMs) and human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) can serve as an unlimited cell source for cardiac regenerative therapy. However, the functional equivalency of both approaches has not been previously reported. Here we performed head-to-head comparison on the beneficial effects of ESC-CM and iPSC-CMs in restoring cardiac function in a rat myocardial infarction (MI) model.
Methods & Results:
Human ESCs and iPSCs were differentiated into cardiomyocytes using small molecules. FACS analysis confirmed ~85% and ~83% of cells differentiated from ESCs and iPSCs, respectively, were positive for cardiac troponin T, and immunofluorescence staining demonstrated that ESC-CMs and iPSC-CMs have striated sarcomeric structure (Figure A-B). Both ESC-CMs and iPSC-CMs displayed similar maturity for calcium handling (transient amplitude: ΔF/F
0
= 3.8±0.3; time to peak: ~200 ms; 50% transient duration: ~400 ms). qRT-PCR showed that ESC-CMs and iPSC-CMs expressed CASQ2, GJA5, KCNJ2, KCNJ5, MYH6, MYH7, and SCN5A at comparable levels to human fetal heart tissue. Next, ESC-CMs and iPSC-CMs were injected into the left ventricular free wall of infarcted hearts (adult nude rats; n=14, 10, respectively). Cardiac function was assessed by MRI one month post cell injection and the hearts were harvested and stained for human cardiac markers. Both ESC-CMs and iPSC-CMs could engraft in ischemic rat hearts (Figure C). Comprehensive functional analysis with small animal magnetic resonance imaging (MRI), echocardiography, and pressure-volume loop analysis are underway.
Conclusion:
We set out to perform head to head comparison for the first time that iPSC-CMs may facilitate cardiac repair at comparable levels to ESC-CMs. Unlike allogeneic ESC-CM therapy, autologous iPSC-CMs could be used to overcome immune rejection for cardiac cell transplantation in the future.
Patient-Specific Induced Pluripotent Stem-Cell Models for Long-QT Syndrome