Table 1.
Biophysical properties of ion currents in hiPSC-CMs and healthy human ventricular myocytes
| Cell type | Current density (pA/pF) | Refs | V 1/2 of activation (mV) | Refs | V 1/2 of inactivation (mV) | Refs | Recovery from inactivation (ms) | Refs | |
|---|---|---|---|---|---|---|---|---|---|
| I Na | hiPSC-CMs | From −12.2a to −272.2 | [30–37, 108] | From −25.5 to −42.4 | [30, 32, 33, 35, 37, 40] | From −61.4 to −85.0 | [30, 32, 33, 35, 37, 40] |
τ = 60.4 t 1/2 = 10.8 τ f = 6.4, 6.0 τ s = 103.6, 118.1 |
[35, 37, 40, 108] |
| Human VM | −49.0 | [38] | −51.0 | [38] | −102.0 | [38] | NA | NA | |
| I CaL | hiPSC-CMs | From −6.6 to ~−58 | [14, 30, 33, 34, 44, 45] | From ~−12 to ~−28 | [14, 30, 33] | −29.1, ~−45 | [30, 33] | NA | NA |
| Human VM | −10.2, −3.8 | [46, 47] | −4.7, −4.2 | [46, 47] | −19.3, −23.5 | [46, 47] | NA | NA | |
| I to1 | hiPSC-CMs | From ~1.3 to ~19 | [26, 30, 33, 52] | From ~10 to ~20 | [26, 30, 33, 52] | ~−40, −41.1 | [33, 52] |
τ
f = 200 τ s = 2380 |
[52] |
| Human sub-epi VM | 6.8, 10.6 | [49, 50] | 9.7, 29.1 | [49, 50] | −31.9, −9.5 | [49, 50] |
τ = 24 τ s = 9621 τ f = 46.1 |
[49, 50] | |
| Human sub-endo VM | 4.4, 2.6 | [49, 50] | 23.1, 32.0 | [49, 50] | −25.3, −17.6 | [49, 50] |
τ
f = 25.0, 90.6 τ s = 328.0, 3109.0 |
[49, 50] | |
| Human VM | 9.3, 8.5b | [46, 51] | ~30, ~20 | [46, 51] | −27.3 | [51] | τ = 27.8 | [51] | |
| I Kr | hiPSC-CMs | From ~0.18 to ~2.5 | [13, 14, 26, 30, 34, 40, 53–56] | From ~−10 to ~−36 | [13, 14, 30, 34, 40, 53, 56] | NA | NA | ||
| Human VM | 0.31, ~0.25, ~0.6 | [46, 57, 58] | ~+22, −5.74 | [46, 57] | NA | NA | |||
| I Ks | hiPSC-CMs | From 0.22 to ~2.9 | [12, 14, 26, 30, 34, 61, 62] | From ~−10 to ~+22 | [12, 14, 26, 30, 61, 62] | X | X | ||
| Human VM | 0.18 | [60] | NA | X | X | ||||
| I K1 | hiPSC-CMs | From ~−0.8 to −5.1 | [30, 34, 53, 68] | X | X | X | |||
| Human VM | From −3.6 to −32.1 | [68] | X | X | X | ||||
| I f | hiPSC-CMs | −4.1, −0.9, ~−3.0 | [30, 34, 48] | −84.6 | [30] | X | X | ||
| Human VM | −1.18 | [71] | −110, −80.0 | [71, 72] | X | X |
I Kr and I Ks density measurements refer to maximal peak tail current, except for the studies of Sala et al. [14], Terrenoire et al. [40], and Ma et al. [30] where I Kr and I Ks are measured at the end of the depolarizing step;
VM ventricular myocytes; V 1/2 (in)activation, half-voltage of (in)activation; τ f and τ s fast and slow time constants of recovery from inactivation, respectively; τ time constant of recovery from inactivation (curve fitted with a mono-exponential equation); t 1/2 time for half of the channels to recover from inactivation; in hiPSC-CMs, I to1 density is measured at +40 mV, while in human VM is measured between +40 and +60 mV; I k1 density values are measured at −100 mV; X channel property does not exist; NA not assessed or measured; ~estimated from figure; sub-epi subepicardial myocytes; sub-endo subendocardial myocytes
a I Na recorded with low extracellular sodium (7 mM Na+) solution [108]
bAverage I to1 density between 0 and +60 mV [51]