Figure 6
Impact of metabolic manipulation on hiPSC-CM functionality. hiPSC-CMs were analyzed in terms of calcium transients (A–D), contractile performance (E–H) and action potential (AP) kinetics (I–L), before (d0) and after 20 days (d20) of culture in different media. Calcium transient kinetics (A–D) evaluated with the intracellular calcium indicator Fluo-4 AM: (A) Representative calcium transient; (B) Calcium transient amplitude (F/F0); (C) Time to peak and time to 50% decay; (D) Average upstroke and decay velocities. n = 28–35 cells per condition from 3 separate experiments. (E) Representative contraction curves, reflecting changes in the percentage of cell length. (F) Percentage of shortening; (G) Maximum shortening and relengthening velocities. n = 20–35 cells per condition. (H) Maximum contractile force generated by hiPSC-CMs in each culture condition. n = 8–17 cells per condition from 3 separate experiments. AP kinetics (I–L) were determined with a voltage-sensitive dye (FluoVolt). (I) Changes in the fluorescence intensity of the FluoVolt AP indicator over time. (J) AP duration at 50% (APD50) and 90% repolarization (APD90). (K) APD50/APD90. (L) AP upstroke velocity. n = 24–26 cells per condition from 3 separate experiments. Data are represented as mean ± SEM. *p < 0.05; **p < 0.01; ***p < 0.001; ns, not significant.
