Table 2.

Most common use of stem cells in regenerative medicine

Stem cells	Advantages	Disadvantages	Selected references	Example of stem cells differentiation into RGCs
Embryonic stem cells	The immense potential of differentiation into any of the cell types	Potential risk of tumour formation and ethical arguments	[1, 60–63, 68, 69, 82–85, 150, 162]	Driving ganglion and amacrine cells from hESCs by using a combination of noggin, dkk1 and IGF-1 [157]; the differentiation mouse and hESCs into RGCs [158]; the differentiation of hESCs and iPSC cells into functional RGCs by applying a stepwise chemical protocol [159]
Induced pluripotent stem cells	The immense potential of differentiation into any of the cell types, no risk of immune rejection; can be directly generated from any adult tissue	Tumorigenic contamination; possible immunogenicity; ethical issues	[45, 71, 72, 74, 88, 89, 100]	The presence of retina ganglion precursor by a synthetic xeno-free culture substrate for iPSCs induction [160]; the development of RGCs and photoreceptors precursors from mouse iPSCs [161]
Adult stem/progenitor cells	A promising resource for autologous transplant, avoiding tumorigenesis and immunosuppression	Poor expansion, survival ability and functional (synaptic) integration of donor cells	[56, 64–67, 70]	Functional differentiation of RGCs from multipotent progenitor cells [162]