Table 4.

Overview of protocols used for differentiation of myotubes from various sources of iPSCs.

iPSCs Source	Protocol	In Vivo/Vitro Efficacy	Stage/Day	Ref.
Human iPSCs	Days 1–7: GSK3 inh, bFGF, Forskolin. Days 8–9: Serum free media. Days 10–36: Horse serum	Insulin-stimulated glucose uptake, glycogen synthase activity, glycogen accumulation	3/36	[160]
Human iPSCs	Days 1–5: GSK3 inh. Days 5–19: bFGF, DMSO. Days 20–35: KSR, ITS-X	Glycogen accumulation	3/35	[169]
Human iPSCs	Days −1–0: DMSO. Days 0–1.5: Insulin, transferrin, FGF2, PI3K inh, BMP4, GSK3 inh. Days 1.5–7: Insulin, Transferrin, FGF2, PI3K inh. Days 8–12: 15% FBS. Days 13–36: horse serum	Spontaneous contractions	3/36	[148]
Human iPSCs	Days 1: MyoD overexpression. Day 3: Adding G418. Day 4: ROCK inh. Day 5: ROCK inh, Dox. Days 6–10: αMEM, KSR, 2-ME. Days 11–13: horse serum, IGF1, 2-ME, Glutamin	Fusion potential both in vitro and in vivo	3/13	[161]
Equine iPSCs	Day 1: mTeSR1 media. Days 2–3: ITS-X, GSK3 inh, ALK inh. Days 4–5: ITS-X, bFGF, GSK3 inh, ALK inh. Days 6–7: IGF1, bFGF, HGF, BMP inh. Days 8–12: IGF1, KSR. Days 12–30: IGF1, KSR, bFGF	Intracellular Ca2+ release in response to KCl-induced membrane depolarization	5/30	[220]
Equine iPSCs	Days 1–14: media containing high glucose, 10% FBS. Day 15: MyoD overexpression. Day 16: washing with PBS and adding puromycin for selection of positive transductants. Puromycin-resistant cells were cultured in high glucose media containing 10% FBS then Dox was added and cells were differentiated for 7 days.	Intracellular Ca2+ release in response to KCl-induced membrane depolarization	?/?	[220]

KSR, knockout serum replacement; ITS-X, Insulin-transferrin-selenium-ethanolamine; HGF, Hepatocyte growth factor; FGF, Fibroblast growth factor; BMP, Bone morphogenetic protein; ALK inh, activin receptor-like kinase inhibitor; 2-ME, 2-Mercaptoethanol; IGF-1, Insulin-like growth factor 1; Dox, Doxycycline.