Table 1.
Comparison of other source of stem cells used for stem cell therapy in degenerative retinopathies disease.
| Type of Stem Cells | Origin | Advantage | Disadvantage |
|---|---|---|---|
| Retinal progenitor cells | Derived from fetal or neonatal retinas [21], if isolated from the developing retina at a suitable stage, photoreceptor precursors may be obtained [26]. | Can migrate into retinal layers, develop morphological characteristics of various retinal cell types [27]. | Ethical and immune rejection issues [28]. |
| Embryonic stem cells (ESC) | Derived from inner cell mass of blastocyst-stage embryos. | ESC can differentiate into photoreceptor progenitors, photoreceptor, or retinal pigment epithelium (RPE) [29,30,31]. | Ethical and immune rejection issues, associated with teratoma formation [32,33]. |
| Induced Pluripotent Stem Cells (iPS) | Pluripotent ESC-like cells reprogrammed in vitro from terminally differentiated somatic cell [34]. | Use as disease model by integrating iPS derived from retinitis pigmentosa patient [35]. iPS can differentiate into functional RPE [35] and photoreceptor precursor cells [36,37]. | It has the risk of viral integrations and oncogene expression [38]. |
| Mesenchymal Stem Cells (MSC) | Bone marrow derived cell population, have the ability to self-renew and give rise to multiple tissue types [39]. Other sources of MSC including adipose tissue, placenta and cord blood [40,41,42,43]. | Could be induced into cells expressing photoreceptor markers [44], the experiment demonstrated that the cells slow down retinal cell degeneration [45]. Some even carried on clinical trials [46,47,48]. | Low rate of cell survival and migration in the retina [49]. Biosafety issues. |
| Olfactory Ensheathing Cells (OECs) | A type of glia cells capable of continuous growth and regeneration of olfactory axons into the CNS [50,51]. | Cleaned up the accumulated debris in subretinal space, and provided an intrinsic continuous supply of neurotrophic factors, reduced the gliotic injury response of Muller cells [20,52]. | Mainly used to promote regeneration of lesion spinal cord axons [50]. |
| Human Neural Progenitors | In the CNS, the cells derived from prenatal cortex. | Could rescue long-term vision function and associated morphologic substrates in a rat model of photoreceptor degeneration [53,54]. | Protected dying host neurons within both the brain and spinal cord [55,56]. |