Induced Pluripotent Stem Cells – New cell replacement therapy
Induced pluripotent stem cells are a new type of pluripotent cells which can be obtained by reprogramming animal and human differentiated cells. Pluripotent stem cells are a unique model for studying a variety of processes that occur in the early developmental phase of mammals and a promising tool in cell therapy of human diseases. The uniqueness of these cells lies in their capability when cultured for unlimited self-renewal and reproduction of all adult cell types in the course of their differentiation. Pluripotency of cells is supported by a complex of signalling molecules and gene network that is specific for the pluripotent cells (1).
Embryonic stem cells
Embryonic stem cells (ESCs) were the only well studied source of pluripotent stem cells. They are obtained from either the inner cell mass or epiblasts of blastocysts. However, there are several constrains for embryonic stem cells to be use in cell replacement therapy. Firstly, the immune incompatibility between the donor and the recipient cell, which can result in rejection of transplanted cells. Secondly, the ethical constraint wherein the embryo dies during the isolation of embryonic stem cells (2,3,4)
Stem cells and their derivatives
The first lines of human pluripotent ESCs were produced in 1998. In line with fundamental importance of embryonic stem cell studies with regard to the multiple processes taking place in early embryogenesis, with possibility of using ESCs and their derivatives as a models for the pathogenesis of human diseases, new drugs testing and cell replacement therapy, These cell derivatives, judging from their biochemical and physiological properties, are potentially applicable for the therapy of cardiovascular disorders, nervous system diseases and human haematological disorders. Induced pluripotent stem cells can become an alternative for ESCs in the area of clinical application of cell replacement therapy and screening for new pharmaceuticals (4,5).
1. Smith A.G. Annu. Rev. Cell Dev. Biol. 2001; 17:435–462
2. Martin G.R. Proc. Natl. Acad. Sci. USA. 1981; 78:7634–7638
3. Evans M.J., Kaufman M.H. Nature. 1981; 292:154–156
4. Thomson J.A., Itskovitz-Eldor J., Shapiro S.S. Science. 1998; 282:1145–1147.
5. Murry C.E., Keller G. Cell. 2008; 132:661–680.