Ion Channel Expression and Electrophysiology of Singular Human (Primary and Induced Pluripotent Stem Cell-Derived) Cardiomyocytes

Figure 2. Comparison of electrophysiological parameters between hiPSC-CM groups. Data are shown as mean ± SD. Students t-test was used to compare groups. *, *** indicate p < 0.05, and p < 0.001, respectively. The numbers of total recordings used to calculate means are listed in Table 2.

Figure 3. Comparison of cardiomyocyte groups regarding ion channel expression at the single-cell level. Columns represent percentages of positive cells; values shown below the columns are mean ΔCT values (CT values normalized to the mean expression of TNNT2 and GAPDH of the respective cell group) of the positive cells. Students t-test was used to compare the ΔCT values between the groups. Significant differences of ΔCT values between groups are indicated with * p < 0.05, ** p < 0.01 and *** p < 0.001. The total numbers used to calculate mean ΔCT values are listed in Table 3. Abbreviations: iCell CMs, iCell cardiomyocytes; v. PCs, ventricular Pluricytes; a. PCs, atrial Pluricytes; pv. CMs, primary ventricular cardiomyocytes; pa. CMs, primary atrial cardiomyocytes.

Figure 1. Histograms of expression parameters. Comparisons of distributions of single-cell expression data (ΔCT) between atrial and ventricular human primary cardiomyocytes and iCell cardiomyocytes. For total n see Table 3. While for some ion channels (SCN5A, KCNH2, CACNA1C, and KCNJ4) the distributions between primary human atrial and ventricular cardiomyocytes are comparable, the distributions of HCN4, CACNA1D, CACNA1G, and KCNA5 are left-shifted (higher expression) in primary human atrial cardiomyocytes compared to primary human ventricular cardiomyocytes. With respect to KCNJ2, distribution is left-shifted (higher expression) for human primary ventricular cardiomyocytes compared to their atrial counterpart. Comparing distributions between the two primary cardiomyocyte groups and iCell cardiomyocytes shows a shift to the left (higher expression) for the pacemaking-associated ion channels HCN4, CACNA1G, and CACNA1D in iCell cardiomyocytes.

Figure 4. Correlation of SCNA5 expression with the fast inward current. For all three hiPSC-CM groups, CT of SCN5A correlates significantly with the fast inward current amplitude. Blue shaded area indicates 95% confidence limits.