What are stem cells and how are they obtained?
Stem cells are an increasingly hot topic: they are used in various fields of medicine, as well as in cosmetology. Let us address what they are, where do they come from and does everyone has access to this unique healing resource.
What are stem cells?
They are the so-called “immature”, i.e. still undifferentiated cells, found in the body of every living multicellular organism.
Practically, every organism, including human body, is equipped with a certain “reserve stock” of stem cells. Their main characteristics are their ability to self-renew, to proliferate (i.e. to form new, identical cells) and even differentiate (i.e. to specialize, as to be able to resume various functions specific for any individual organ). The term “stem cell” was first introduced in 1909. Their function was studied throughout the XX century, by scientists from all around the world, who have continuously been acquiring new knowledge about their role in a body and possible ways to use them.
One’s own stem cells are referred to as “autologous” stem cells.
During the fetal phase of development, all the inner organs, blood vessels, skin and other organs are being formed from stem cells. Since the process of cell differentiation is happening before birth, this is the period when stem cells are most numerous. They are being stored in umbilical blood, umbilical cord tissue and placenta.
Stem cells can also be found in adults. This is a sui generis “repair toolkit”, used by the body, to help reparation and regeneration of damaged organs and tissues. The older the person gets, the less stem cells exist, so that possibilities to “repair” any afflicted organ become fewer. The decreasing of the number of stem cells and the slowing down of their production by the body is a natural process and a part of the process of aging.
Stem cell treatment
During the 1970ies, rejuvenation by stem cells has become very popular. The “injections of youth” were available only to the extremely affluent people from Europe, US and to eminent members of the Soviet Communist party. Those were the people who did not want to be subject to the effects of aging, rich or influential enough to have stem cells injected into their bodies, in order to activate processes of body rejuvenation. Nowadays, stem-cells preparations are being actively used in cosmetology and gerontology.
The biological potential of stem cells to treat many diseases (including the most serious ones, previously deemed as incurable) are of a great interest for science and opening new perspectives. Several dozens of such diseases are already on the list of treatable ones.
Stem-cell therapy is opening great possibilities for reconstructive medicine. They are already being used, in numerous countries (including Ukraine) in treatment of high-degree chemical and thermic burns and scalds. Namely, thanks to their ability to differentiate into cells of any given bodily tissue, stem cells are very helpful in regeneration of big areas of skin. In the case of therapy by autologous stem cells, there is no risk of rejection, as opposed to the cases of usage of material obtained from donors.
Cardiology is another promising field for the usage of stem-cell therapy. Ukraine is currently conducting clinical research about stem-cell treatment of cardiomyopathy and decreased hearth contractility. Stem-cell preparation can help survival of patients with serious heart conditions while they are awaiting heart transplantation.
Stem cells are also used in treatment of liver cirrhosis. Additionally, medical practitioners in Ukraine already have a successful practice in treatment of serious pancreatic pathologies with biological preparations.
The usage of undifferentiated stem cells can prolong life expectancy and significantly improve quality of life for diabetic patients. It is known that diabetes causes vascular lesions of various severity, which can lead to development of trophic ulcerations, also known as “diabetic foot”.
Encouraging positive results have also been obtained in stem-cell treatment of multiple sclerosis, Crohn’s disease, Parkinson’s disease, heart failure, rheumatoid arthritis, leukemia and malignant tumors in various locations.
Clinical research about stem-cell therapy of all the above-mentioned pathologies have already been successfully conducted in Ukraine.
Human stem cells
Stem cells differ in terms of their origin, i.e. the source from which materials are obtained. In addition to the usage of embryonal and fetal stem cells, which raises very serious ethical considerations, there is also a possibility of isolating the “immature” (i.e. undifferentiated) stem cells, without causing any bodily harm to the person that the cells are being taken from (patient himself, or the donor), i.e. without a possibility of coming into a conflict with ethical standards. Such stem cells can be:
Adult postnatal stem cells. They are obtained from a bodies of adults (as already mentioned, bodies of adults create small numbers of undifferentiated stem cells). Problem with this type of stem cells is that most of them have already undergone some type of differentiation, which significantly decreases possibilities for their usage.
However, the usage of autologous postnatal stem cells has a significant advantage in terms of eliminating the risk of post-transplantation rejection by the patient (because it is patient’s own biological material).
Umbilical stem cells. They also belong to postnatal stem cells, but, as they are extracted from umbilical (i.e. very young) tissue, they are the least differentiated of all the ‘’mature’’ stem cells. As they can still differentiate into cells of any tissue or organ that needs being repaired, their repairing potential is very high, so that they can be used, when needed, for treatment of a very wide range of diseases (e.g in gerontology or in rehabilitation of patients).
Depending on the ‘’task’’ that undifferentiated stem cells can accomplish, they are divided into three types:
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called hematopoiesis. They can be isolated from umbillical cord blood, as well as from adult bone marrow and they are used for transplantations in cases of blood-related malignant diseases.
Mesenchymal stem cells (MSCs) are the stem cells that give rise to bone, cartilage or fat cells. They can be isolated from umbilical cord blood, umbilical cord and placenta. They are being actively used in treatment of diabetic foot (for regeneration of the skin), as well as in treatment of diseases affecting muscular-skeletal system and, especially, joints.
Progenitor cells are descendants of stem cells that then further differentiate to create specialized cell types. There are many types of progenitor cells throughout the human body. As opposed to undifferentiated stem cells, progenitor cells are only capable of differentiating into cells that belong to the same tissue or organ.
