25 March 2009

Medicine of the Future: human embryonic stem cells

Stem cells have an amazing potential to develop into various types of cells in the body. Theoretically, they can be shared an unlimited number of times and replace others. When a stem cell divides, each of the newly formed cells has the ability to remain a stem cell or become a different type of cell: muscular, nervous, etc., performing a certain function. One of the main directions in research conducted on stem cells is the study of the possibilities of using human embryonic stem cells (hESC). Today, it has received a powerful incentive to develop in the United States – this was facilitated by a change in government policy in this area: for the first time in more than 7 years, restrictions on financing hESC research from federal funds will be lifted.

Such tests will allow us to answer the question of how the development of an integral organism from a single cell takes place. HESC attracted the attention of researchers due to its almost unlimited development potential (Yu J., Thomson J.A., 2006). The ability of these cells to divide and grow promises to provide an unlimited supply of specialized cell types – both for research and for the treatment of a wide range of diseases.

hESCs are extracted from embryos at a stage of development when they are not normally implanted into the uterus. During this period, in the cells of the embryo (blastomeres) the process of differentiation (acquisition of special traits by cells to perform special functions) has not yet begun, and each of them has the potential capabilities of any cell in the body.

The first differentiation is noted when the embryo is about 5 days old: the outer layer of cells is preparing to become part of the placenta, and the inner layer gives rise to the development of body tissues. If the hESC of the inner layer is removed from the normal embryonic environment and cultured under certain conditions, they will continue to divide, still having the potential to form any type of cell.

Embryonic stem cells were first obtained in mice in 1981 (Evans M.J., Kaufman M.H., 1981), and the first report on the isolation of hESC culture appeared only 17 years after that (Thomson J.A. et al., 1998). HESC is obtained from embryos by artificial insemination in vitro (in vitro fertilization – IVF). In the USA alone, more than 400,000 embryos obtained using the IVF technique are stored (Hoffman D.I. et al., 2003).

Although attempts to obtain hESC have been made since the 80s of the twentieth century, there have been problems associated with embryo cultivation for a period sufficient to isolate cell lines. After optimizing the cultivation medium, it was possible to isolate hESC. Today they are very valuable material for research that can help in the creation of methods for the treatment of a wide range of degenerative diseases, the consequences of injuries, genetic abnormalities, etc.

The study of hESC provides unlimited opportunities for transplant treatment techniques, research of new drugs; it also provides an in vitro model for the study of tissue differentiation and allows deeper insight into problems such as infertility and congenital defects of fetal development.

Given the fact that hESC tests have been carried out for a little more than 10 years, scientists have yet to investigate many more of their fundamental properties. In particular, it is necessary to answer the question of how exactly stem cells manage to remain non-specialized and self-renewing for many years: why are hESCs able to divide without differentiation for longer than a year in the laboratory, and most adult stem cells are not. The latter were discovered back in the 60s of the twentieth century. and they are undifferentiated, capable of restoring the tissue in which they are located. It is also necessary to determine many factors that cause the specialization of stem cells. Thus, hESC research allows scientists to penetrate into a field that was previously under seven seals, and open up new opportunities for modern medicine.

Nevertheless, the hESC tests raise complex ethical issues, the topic of which is actively discussed in the world community. Opinions on this issue are often directly opposite, which is explained by the clash of scientific interests and ethical issues.

Ethical, social, legal, philosophical and other interrelated controversial issues that arise in the biological sciences and the health care system are studied by bioethics.

hESC research is actively conducted in the UK, Sweden, Belgium, Canada and New Zealand, but in some countries (Austria, Lithuania and Poland) they are prohibited by law.

In the USA, the state policy regarding this sphere has recently changed dramatically. Thus, starting in August 2001, a ban was imposed on the use of funds from federal funds for hESC research, with the exception of those lines of these cells that have already been allocated. The authority of the U.S. Department of Health and Human Services and the National Institutes of Health (NIH) to fund and conduct hESC research has been significantly limited.

Since federal funds are the main source of funding for any medical research in the United States, especially at the early stages, this has significantly slowed down their development. Most scientists, acting within the limitations, were unable to continue the tests because there were not enough hESC lines available to carry them out.

According to US President Barack Obama, in recent years the wrong choice has been made between the voice of science and moral values: "Scientists believe that these cells can help to understand many diseases and possibly cure them. As a believer, I believe that our vocation is to take care of each other and alleviate human suffering."

According to the decree of the President of the United States of 9.03.2009 NIH should develop new detailed guidelines to manage the conduct of hESC research. It is assumed that federal funding will be used to conduct research on hESC lines obtained with parental permission from embryos that have remained unclaimed in infertility treatment clinics and are subject to destruction.

The change in the state policy in the field of hESC research not only became a resonant event for the scientific community, but also immediately caused the appearance of "circles on the water": as reported by Reuters, there is an increase in the value of shares of companies engaged in stem cell research. According to rough estimates, the number of new hESC lines ranges from 400 to 1000. However, the US government is not going to give permission for the use of cloning technologies.

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