Embryonic Stem Cells

Embryonic stem cells are obtained from human embryos. The blastocyst contains stem cells and will later implant in the womb. Embryonic stem cells come from a blastocyst that is 4–5 days old. When scientists take stem cells from embryos, these are usually extra embryos that result from in vitro fertilization (IVF).

These cells have limitless expansion and pluripotency potential. Pluripotency is the ability to differentiate into any cell type. They play a significant role in regenerative medicine as well as tissue replacement after disease or injury. Embryonic stem cells can differentiate into more cell types than adult stem cells.

Embryonic stem cells are pluripotent, meaning they are able to grow (i.e. differentiate) into all derivatives of the three primary germ layers: ectoderm, endoderm and mesoderm. In other words, they can develop into each of the more than 200 cell types of the adult body as long as they are specified to do so. Embryonic stem cells are distinguished by two distinctive properties: their pluripotency, and their ability to replicate indefinitely. ES cells are pluripotent, that is, they are able to differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. These include each of the more than 220 cell types in the adult body.

The capacity of embryonic stem (ES) cells for virtually unlimited self renewal and differentiation has opened up the prospect of widespread applications in biomedical research and regenerative medicine. The use of these cells would overcome the problems of donor tissue shortage and implant rejection, if the cells are made immunocompatible with the recipient. Since the derivation in 1998 of human ES cell lines from preimplantation embryos, considerable research is centered on their biology, on how differentiation can be encouraged toward particular cell lineages, and also on the means to enrich and purify derivative cell types. In addition, ES cells may be used as an in vitro system not only to study cell differentiation but also to evaluate the effects of new drugs and the identification of genes as potential therapeutic targets.