What is stem cell?
This is probably the first question you would have in mind: what actually stem cell is?
In brief, stem cells are cells that can replenish themselves through cell division and become (differentiate) other types of cells with a more specialized function, e.g. neurons, muscle cells, liver cells.
In mammals, stem cells can be broadly categorized into two types based on their sources:
1. embryonic stem cells (ESCs)
2. adult stem cells (ASCs)
The potency (i.e. the ability to become other cell types) of ASCs is more restricted, whereas that of ESCs is higher.
A decade ago, it was demonstrated that differentiated mammalian cells could be genetically reprogrammed into ESC-like cells (induced pluripotent stem cells; iPSCs) by over-expressing certain transcription factors.
This ground-breaking discovery pointed out the possibility of
(i) resetting the developmental program of a human cell in a culture dish, and
(ii) using a person's body cells to generate other cell types for autologous cell therapy.
Since then, a lot of studies have been carried out by scientists all over the world to improve and simplify the reprogramming procedure, and to generate different types of human cells from blood cells or skin cells, on culture dishes, for a variety of basic and genetic researches. Meanwhile, clinical trials of human iPSCs and cell types derived from them for the treatment of specific disorders have been initiated in the US, Europe and Japan.
For more information, we recommend you to check out the following websites:
Embryonic stem cell (from Wikipedia)
Stem cell basics (from the National Institutes of Health, USA)
Professor Shinya Yamanaka (Kyoto University, Japan)
