Embryonic stem cells (ES cells) are obtained by extracting cells from the inner cell mass of very early embryos at the blastocyst stage (4-5 days post fertilization). These cells are then grown in a laboratory provided that the necessary conditions are provided. Blastocysts that are produced as the result of in vitro fertilization but were not utilized for implantation provide a source for ES cells. In some countries these unused blastocysts can be donated for medical research provided that the donors have provided consent to the use thereof (1).
ES cells possess two very unique properties which have drawn a keen interest from both Sciences and Medicine alike. As these cells are obtained from early blastocysts, at a very early stage of development, they maintain the ability or “potency” to develop and differentiate into any one of the more than 200 cell types found throughout the human body. This is known as “pluripotency”
The second very important characteristic these cells posses is their “immortality”. ES cells have the ability to divide indefinitely, remaining in an undifferentiated state. This means that unlimited quantities of genetically-identical, pluripotent stem cells can be grown in a petri-dish for medical use (2).
Despite the advantages associated with the use of ES cells in research, its use as therapeutic tool remains obscure. Since the initiation of ES cell research in the 1980’s, the ability to control the division of ES cells and the subsequent risk of tumor formation, inappropriate tissue growth and immune rejection still eludes leading scientists (3). Leading researchers still note that it will be long before ES cells can be used on patients in a safe and efficient manner.
While research on the translation of ES cells from the lab to clinical setting is ongoing, hundreds of studies have reported on the advantages of implementing adult stem cells in cell therapies. It remains a matter of great importance however that scientists and researchers pursue all areas of regenerative medicine in order to fully understand the full capabilities of these cells.
Various scientific reviews, debates and discussions have been launched regarding the ethics surrounding the use of ES cells in research. For further reading material please follow these links: