Table 2: List of sources of stem cells. Their advantages and disadvantages.
|Stem cell type||Sources||Advantages||Disadvantages|
|Embryonic||Cells from human blastocysts||Pluripotent||Requires embryo destruction|
|Fetal stem cells||Cells from gonads of aborted fetuses||Multipotent||Requires destruction of weeks old fetus|
|Umbilical cord stem cells||Cells from the umbilical cord blood of newborns||Multipotent/Pluripotent?||Low frequency of stem cells|
|Placenta-derived stem cells||Cells from the placenta of newborns||Multipotent/Pluripotent?||Low frequency (but higher than cord blood)|
|Adult stem cells||Cells from adult tissues||Multipotent||Very low frequency|
|Induced pluripotent stem (iPS) cells||Cells from adult tissues reprogramed to pluripotency||Pluripotent||Not patentable|
The stem cells are the promising tools addressing generation of beta-like cells/ISC (Insulin secreting cells) as well as immunomodulation (Figure 2) .