Scientists isolate embryonic stem cells from early embryos, mainly donated
embryos remaining fromin vitrofertilization. Another possible source of human
embryonic stem cells could be embryos created in the process of somatic cell
nuclear transfer. In this process, a nucleus of an unfertilized egg cell is removed
and replaced by a nucleus removed from a somatic cell. An emptied egg cell and the
nucleus of the somatic cell are then merged together by electrical impulses. Such a
cell is then stimulated to start dividing, resulting in an embryo, which is genetically
almost identical to the person that donated the somatic cell. Embryonic stem cells
can then be harvested from such embryos for the purpose of medical treatment or
research. This process is often called therapeutic cloning.^2 In addition, embryonic
stem cells could also be isolated from embryos created through a process called
parthenogenesis. In this process, an unfertilized egg cell is stimulated by certain
chemical compounds to start duplicating its genetic material and dividing as if it
were fertilized. The result is an embryo-like structure from which embryonic stem
cells, genetically very similar to the donor of the egg cell, can be harvested.^3
Ever since human embryonic stem cells were first isolated in 1998, many stem
cell studies have confirmed the initial presumptions that stem cells have a vast
potential in the research and treatment of numerous serious injuries and illnesses
that were previously thought to be untreatable. Scientists consider stem cells, and
especially embryonic stem cells, to be extremely important in researching the
complex events of human development. Their basic objective is to identify what
exactly triggers stem cell differentiation. For now it is known that genes play the
main role in this process; however, there is not enough knowledge about the signals
responsible for turning particular genes on or off at a particular moment, which
affects cell differentiation. Gaining such knowledge is of great importance since the
most grievous health conditions, such as various types of cancer or inherent defects,
are actually a consequence of abnormalities in cell division and differentiation. A
better understanding of genetic and molecular triggers of these processes could
bring about a better understanding of causes of these health conditions and con-
tribute to the development of new, personalized, and therefore more efficient
methods for their treatment, or even prevent their occurrence.^4
Another very important role of stem cells in medicine is their use in testing new
drugs. Stem cells could help in avoiding today’s model of long-term drug testing on
animals, wherein it is not always possible to predict the effects that a drug that is
being developed will have on human cells or tissues. In that sense, stem cells could
be used for the production of differentiated cells and tissues that would mimic the
progress of the illness. These cells and tissues could then be used in the testing of
drugs for the treatment of the illness. In such way, the effectiveness of a certain drug
(^2) For more information on human cloning, see, e.g., UNESCO ( 2005 ).
(^3) For more information on parthenogenesis, see, e.g., Wilmut ( 2007 ).
(^4) For more information on the use of stem cells for research, see, e.g., DHHS ( 2001 ); Jones and
Thomson ( 2000 ); Rathjen et al. ( 1998 ).
Embryonic Stem Cell Patents and Personalized Medicine in the European Union 55