Regenerative medicine is a new, multidisciplinary field that targeted at the repair or replacement of the damaged or diseased human cells, tissues or organs to restore normal function. The two main components of regenerative medicine are stem cell therapy and tissue engineering. Stem cells, with their ability for extensive proliferation and multi lineage differentiation, can serve as a renewable source of cellular material in regenerative medicine.
Human pluripotent stem cells (hPSCs), including Embryonic stem cells and induced pluripotent stem cells due to their inherent capacity to grow indefinitely and to differentiate in all mature cell types in the body have made them attractive tools for regenerative medicine and tissue engineering.
There were two kinds of stem cells:
1. Embryonic stem cells: Cells derived from the inner cell mass of the embryos. They can differentiate into all cell types that compose an adult body, derived from the three germ layers. This property is known as pluripotency. In addition, they possess limited proliferative capacity in vitro and their differentiation potential is restricted to the original cell lineage. Human embryonic stem cell cultures were originally grown on “Feeder layers” of mouse fibroblast cells and serum-containing medium.
2. Adult stem cells: Found in tissues or organs. Adult stem cell is an undifferentiated cell, found among differentiated cells in a tissue organ that can renew itself. They exist in the different organs like bone marrow, peripheral blood, pancreas, lung etc. reside in a specific area of each tissue called “Stem cell niche”.
The ability of a stem cell of one lineage to become another lineage is called transdifferentiation.
