Table 1.

Comparison of therapeutic approaches to skeletal muscle repair and healing.

	Cell-based therapy (iPS-derived cell/stem cell sheet)	Gene therapy (microRNA)	Growth factor therapy (bFGF, IGF, NGF, PDGF, TGF-β)	Peptide therapy (SVVYGLR)
Route of administration	Requires many cells	Direct administration	Direct administration	Direct administration
	Scaffolding material required	(Scaffold material required)	(Scaffold material required)	(Scaffold material not required)
	(Thoracotomy required for heart)	Excellent operability by use of viral vector and lipid nanoparticles	Short biologic half-life in vivo/instability of effective concentration	Low molecular weight and applicable to various dosage forms (emulsion, ointment, etc)
			(Need for multiple factors)
Safety/toxicity/metabolism	Risk of malignant transformation	Risk of immune response and gene mutation	Risk of immune response and adverse effects	Small molecules with fast metabolism/lower risk of immune response
	Risk of bacterial or viral infections and transmission	Off-target effects
Synthesis/cost	High cost in terms of productivity and quality control, time-consuming process (culturing and adjusting transplanted cells in a sterilized environment)	Manufacturing cost is relatively low	High-cost issue	Possible to synthesize in large quantities with lower cost (highly efficient synthesis methods have been established)
		High-cost issue in terms of quality control	(Time restriction from dispensing to administration to avoid denaturation and decreased activity)