Stem cells are primal, undifferentiated cells, which have the unique potential to produce any kind of cell in the body. Medical researchers believe stem cells have the potential to change the face of human disease by being used to repair specific tissues or to grow organs.
Stem cells which derived from the inner mass cells of a blastocyst (an early embryo) have “pluripotent properties they are able to grow into any of the 200 cell types in the body” (C, Brownlee. 2005). Embryonic stem cells can be obtained from a cloned blastocyst, created by fusing a de-nucleated egg cell with a patient's cell. The blastocyst produced is allowed to grow to the size of a few tens of cells, and stem cells are then extracted. Because they are obtained from a clone, they are genetically compatible with the patient. Aggregates of cells derived from embryonic stem cells are known as embryoid bodies.
The breakthrough in embryonic stem cell research came in November 1998 when a group led by James Thomson at the University of Wisconsin-Madison first developed a technique to isolate and grow the cells. Embryonic stem cell researchers are currently attempting to grow the cells beyond the first stages of cell development, to overcome difficulties in host rejection of implanted stem cells, and to control the multiplying of implanted embryonic stem cells, which otherwise multiply uncontrollably, producing cancer.
A major development in research came in May 2003, when researchers announced that they had successfully used embryonic stem cells to produce human egg cells. These egg cells could potentially be used in turn to produce new stem cells. If research and testing proves that artificially created egg cells could be a viable source for embryonic stem cells, they noted, then this would remove the necessity of starting a new embryonic stem cell line with the destruction of a blastocyst..........
