Acute effects of cardiac contractility modulation stimulation in conventional 2D and 3D human induced pluripotent stem cell-derived cardiomyocyte models

Figures

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  FIGURE 1. 2D and 3D hiPSC-CM CCM models (A) Effect of standard clinical CCM signal on conventional 2D (stiff substrate) and (B) 3D ECT hiPSC-CM models. Representative contraction recordings before CCM (Baseline), during CCM (7.5 V) and after CCM (recovery) in 2D hiPSC-CM monolayer and 3D ECT. 3D ECTs displaying enhanced CCM-induced force. White arrow indicates edge of 3D ECT where force transducer was connected (C) Baseline (Control) pacing waveform (Top) and standard biphasic CCM waveform (i.e., two biphasic pulse, 7.5 V, 5.14 ms duration, 30 ms delay) (Bottom). (D) Schematic contractility waveform depicting key contractile parameters evaluated. Contraction slope and relaxation slope were calculated as maximum and minimum of the time derivative of the contractility amplitude respectively. White square indicates region of interest of 2D monolayer.

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  FIGURE 2. CCM Pulse Waveforms Evaluated. Waveforms depicting CCM Parameters Tested (A) Pulse Delay 1–160 ms, additional parameters fixed at duration 5.14 ms, amplitude 7.5 V and pulse number 2. (B) Pulse Duration 4.5–7 ms, additional parameters fixed at delay 30 ms, amplitude 7.5 V and pulse number 2 (C) Pulse Amplitude 1–10 V, additional parameters fixed at delay 30 ms, duration 5.14 ms and pulse number 2. (D) Pulse Number 1 to 3 Pulses, additional parameters fixed at delay 30 ms, duration 5.14 ms and amplitude 7.5 V. Pulse waveforms not to scale (ImpulseDynamics, 2018; ImpulseDynamics, 2019).

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  FIGURE 3. Effect of Extracellular Ca Modulation on CCM Response in 2D and 3D models (A) Representative contraction traces for baseline (i.e., field stimulation pacing, 1 Hz). and CCM for 2D hiPSC-CMs monolayer and (B) 3D ECTs. CCM was applied as the standard biphasic CCM waveform (i.e., two biphasic pulse, 7.5 V, 5.14 ms duration, 30 ms delay). hiPSC-CMs were exposed to increasing concentrations of extracellular Ca [Cao] 0.5–4 mM (C) Summary data graphs. Data are mean ± SEM. n = 3 – 6 per group. * p < 0.05 (3D vs. BL), # p < 0.05 (3D vs. 3D), + p < 0.05 (2D vs. BL).

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  FIGURE 4. Effect of CCM pulse delay on 2D and 3D hiPSC-CM contractile properties (A) Representative contraction traces for baseline (i.e., field stimulation pacing, 1 Hz). and CCM for 2D monolayer hiPSC-CMs and (B) 3D ECTs (C) Summary data graphs. Data are mean ± SEM. n = 3–6 per group. * p < 0.05 (3D vs. BL), # p < 0.05 (3D vs. 3D), + p < 0.05 (2D vs. BL).

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  FIGURE 5. Effect of CCM pulse duration on 2D and 3D hiPSC-CM contractile properties (A) Representative contraction traces for baseline (i.e., field stimulation pacing, 1 Hz). and CCM for 2D monolayer hiPSC-CMs and (B) 3D ECTs (C) Summary data graphs. Data are mean ± SEM. n = 3–6 per group. * p < 0.05 (3D vs. BL), # p < 0.05 (3D vs. 3D), + p < 0.05 (2D vs. BL).

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  FIGURE 6. Effect of CCM pulse amplitude on 2D and 3D hiPSC-CM contractile properties (A) Representative contraction traces for baseline (i.e., field stimulation pacing, 1 Hz). and CCM for 2D hiPSC-CMs monolayer and (B) 3D ECTs (C) Summary data graphs. Data are mean ± SEM. n = 3–6 per group. * p < 0.05 (3D vs. BL), # p < 0.05 (3D vs. 3D), + p < 0.05 (2D vs. BL).

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  FIGURE 7. Effect of CCM pulse number on 2D and 3D hiPSC-CM contractile properties (A) Representative contraction traces for baseline (i.e., field stimulation pacing, 1 Hz). and CCM for 2D monolayer hiPSC-CMs and (B) 3D ECTs (C) Summary data graphs. Data are mean ± SEM. n = 3–6 per group. * p < 0.05 (3D vs. BL), # p < 0.05 (3D vs. 3D), + p < 0.05 (2D vs. BL).