Introduction
The concept of “stem cells” first appeared in Russia at the beginning of the last century. What are these cells and what are their distinguishing features? Stem cells are cells which can give a rise to any cells in a body – skin, nerve and blood cells. What is more, stem cells can be isolated and grown in tissue culture. The ability to provide a wide variety of cell types from stem cells makes them an important reserve in a body, which is used to fill defects arising due to various circumstances even though stem cells remain to be in the center of a heated discussion.
Body
Stem cells can transform into cells of all types of tissue: blood cells, internal organs, muscle and bone tissue, skin, neurons, etc. In the early stages of its development, a human body is almost entirely composed of stem cells which gradually acquire specialization, that is, organs and tissues of a body are formed from them. Thus, stem cells are, first of all, a kind of a building material of a body. They also take a direct part in the regenerative processes in a body and may slow the aging process. Due to their ability to transform into cells of all organs and tissues stem cells play the role of “the first aid” (Thurm et al. 68); if there is a problem somewhere in a body, stem cells are sent there to replace the loss due to a disease or damage to a body, and its function is regained. With age, the number of stem cells is reduced and the regenerative potential of a body is reduced as well.
The discovery of stem cells is in line with the great achievements of mankind such as the discovery of double-stranded DNA chain, or decoding the human genome. Biologists A. Friedenstein and I.Chertkovy opened Mesenchymal stem cells (MSCs) in a bone marrow with a unique regenerative capacity (Grens et al. 96). This discovery was developed by American scientists who found human embryonic stem cells and demonstrated their ability to differentiate into virtually all cell types of a human body. However, the use of embryonic stem cells in the world are now frozen as their safety in terms of carcinogenicity is still not proven. Today, stem cell therapy has become one of the promising areas of future medicine. Many countries have established numerous clinics and centers that use cellular technology in the treatment of diseases; scientific and practical innovations associated with the stem cells promise to be revolutionary and fundamentally change the approach to the treatment of many serious diseases. One of the fathers of the brilliant opening of the century – the double helix of DNA – James Watson noted that stem cells device is unique because under the influence of external factors they have the ability to differentiate into a variety of ways, forming new pools of virtually all types of cells. Thanks to them, tissue regeneration is possible (Thurm et al. 96).
The use of stem cells to treat and prevent a wide range of diseases has led to active development of cellular technology (Cinquin 88). At the present time the developed countries have set up and operated multiple clinics with various specializations that use stem cells. Medicine does not stand still, and soon many diseases, especially ones considered to be incurable, can be cured with stem cells. Stem cells are used for different purposes, the main of which are treatment and cosmetology. In order to use stem cells for these and other purposes clinics and medical centers are established in many countries. However, it should be noted that not all of these clinics and medical centers are licensed to use stem cells (Thurm et al. 87).
As any other discoveries, stem cell technologies have their pros and cons. As mentioned before, stem cells are classified by origin into several types: embryonic, fetal, umbilical cord blood stem cells and adult cells (Thurm et al. 86). Each of them differs in their properties and has different use. Thus, embryonic SC, which can be obtained from the blastocyst (day 5 of fetal development), are able to differentiate into any cell of a completely adult organism. However, this is their main disadvantage: embryonic cells have unacceptably high propensity to regenerate not only healthy, but also cancer cells. So, the world has not yet selected a safe line of embryonic SC, suitable for clinical use (Cinquin 63).
Fetal SC can be obtained from 9-12 week fetal development. This method of producing is the main obstacle to the study and clinical application of this variety of stem cells. Legislation of many countries prohibits or significantly restricts abortion research material for ethical reasons. The legal obstacles to the use of such material in medical practice, particularly in hospitals and commercial centers, are even more serious. The decision to transfer an embryo to create stem cells should be taken by a donor independently from abortion decision and without being encouraged with the financial rewards so that it does not become an incentive for abortion (Guindon et al. 85).
The easier way to receive stem cells is their collection from placental umbilical cord blood after birth and its cryopreservation. To date, it is worldwide accepted that the best source for hematopoietic SC is umbilical cord blood. Besides all the health benefits, umbilical cord blood is the cheapest and safest source of SC. However, in many samples of cord blood stem cells amount is low, so their use may be limited. The resulting blood can be stored in a canned form in the interest of a child and his family, as well as of a donor to those in need of patients for experimental and research work (if parents of a child before birth signed agreement that they waive all rights to stem cells) (Salic et al. 65). In the USA, parents hand over the child's cord blood for storage in 10% of births; the initial payment for the service is $600, storage itself costs from 100 to 2,000$, depending on the security and storage conditions (Thurm et al. 43).
It is a little bit easier with the legal and financial points of view to obtain stem cells of an adult. Their concentration is maximal in the adult bone marrow where there are two types of stem cells: hematopoietic and mesenchymal. The work on the release of SC from bone marrow and blood has intensified in the late 80s: in many respects, this progress has been associated with the need to treat radiation sickness in the victims of the accident at the Chernobyl nuclear power plant. Bone marrow transplantation was practiced earlier, but due to the Chernobyl disaster in a very short period of time people had to deal with the storage of bone marrow, release of hematopoietic stem cells and their application in clinical practice. Subsequently, this technique has been refined and perfected to extract stem cells from peripheral blood after mobilization – the introduction of special substances that stimulate the release of stem cells in the blood (Thurm 98).
Overall, people should not forget the importance of limitation which prevents the widespread use of the SC in the practice of medicine: people need a thorough check of the source of stem cells for infection with herpes viruses, hepatitis, human immunodeficiency and other dangerous infections. The cost of laboratory tests increases the cost of using stem cells and responsibility for possible complications.
Conclusion
Finally, no other area of biology at its birth was surrounded by a network of prejudice, hostility and misunderstanding as greatly as stem cells were. Today, the use of stem cells is often associated with cloning, but it is, in turn, the cultivation of human embryos “for parts” (Cinquin 39). Clonophobia gained a considerable extent and has been successfully used by religious denominations, political and public figures and trends for their own purposes. For example, a rector of the Church of the Exaltation of Christ says: “Treatment of embryonic stem cells is cannibalism from a moral point of view. Such things are prohibitive – it is Satanism” (Cinquin 38). These medieval views, supported by a large number of people, severely limit scientific research in the field of stem cells. In contrast to the clergy, the leading experts in the WHO believe that everything that is important and valuable for human health should be accepted and allowed. Surely, it is not possible to allow any abuses in this area. Therefore, the issues of cloning and cellular technologies are solved in each country in its own way.
