[Electrophysiological identification of human induced pluripotent stem cell-derived cardiomyocytes]

The present study was aimed to characterize the electrophysiology of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). IMR90-4 cells were induced to differentiate into cardiomyocytes by temporal modulation of regulators of canonical Wnt signaling. The protein expression of cardiac troponin T (cTnT) was detected by immunofluorescence staining and flow cytometry, and the differentiation rate of hiPSC-CMs was calculated. The action potentials (APs) of hiPSC-CMs were recorded by patch clamp and used to classify different types of cardiomyocytes. The electrophysiological characteristics of hiPSC-CMs were further analyzed. The results showed that the cTnT positive rate of hiPSC-CMs was above 95%. hiPSC-CMs were differentiated into 3 types of cardiomyocytes based on the properties of AP: ventricular-, atrial- and nodal-like cells. In comparison with the other two types of cells, the APs of ventricular-like cells exhibited longer duration, higher amplitude and higher dV/dt_max. The nodal-like cells had the lowest dV/dt_max among all the three types. These results indicate that hiPSC can be differentiated into the cardiomyocytes with high purity and the differentiated hiPSC-CMs have similar electrophysiological characteristics to adult cardiomyocytes.