A review paper here looks over the biochemistry, similarities, and differences between embryonic stem cells and induced pluripotent stem cells, both of which are presently used in the development of new therapies, but the former is far more limited by regulation than the latter:
Embryonic stem cells (ESCs) are derived from the inner cell mass of the blastocysts and are characterized by the ability to renew themselves (self-renewal) and the capability to generate all the cells within the human body. In contrast, inducible pluripotent stem cells (iPSCs) are generated by transfection of four transcription factors in somatic cells. Like embryonic stem cells, they are able to self-renew and differentiate. Because of these features, both ESCs and iPSCs, are under intense clinical investigation for cell-based therapy.
Since the first isolation of human Embryonic Stem Cells (ESCs) huge interest has developed in the scientific and clinical communities and in the public in general because of their therapeutic potential. In particular, attention has focused on their potential use in cell-based therapy for diseases that are refractory to conventional treatments, such as neurodegenerative diseases and immunodeficiency, because of their ability to be programmed into new mature differentiated cells of all lineages.
Although our knowledge of the molecular mechanisms that control the self-renewal and differentiation of stem cells has grown considerably during the past decade, we still need more basic research in order to understand the molecular mechanisms that regulate proliferation, survival and differentiation of stem cells particularly after transplantation and in the pathological environment.