DO STEM CELL CLINICAL PERSPECTIVE?

Many diseases are accompanied by cell death, the body can not naturally replaced. Sometimes cells die suddenly, such as myocardial infarction. In other cases, the process is slow and inevitable, such as Alzheimer's disease. Most clinical perspective stem cells (which are the equivalent of a reduction of energy for the body) - is that they can be made by specialized, ie, they will be replacing the body's cells that were lost due to disease.

However, quite a difficult obstacle to scientific point of view, ethics and even the intervention of politicians slowed progress in this field for more than ten years. However, over the past two years there has been a marked shift in the field through a series of remarkable discoveries: suddenly be possible to create cells that have the potential of embryonic stem cells without the use of embryos. This made it possible to eliminate most of the ethical issues related to research in the field of stem cells. Embryonic stem cells are characterized by two extraordinary properties that make them potentially useful for practical applications in medicine. First, they are "pluripotent", that is the ability to turn into any type of specialized cells of the body: myocardial cells, pumping blood, acid-cells of the gastric mucosa, the light-sensitive cells of the retina, or brain cells that retain information. Second, embryonic stem cells have the ability to continuously divide and create unlimited copies of their fellow cells - is the most important property, because to replace cells lost due to disease, there is a need for a huge number of new ones. The scientists also studied stem cells in adults. In such studies, no ethical issues arise, as in the case of embryonic stem cells, because they do not use human embryos. Bone marrow and organs such as the heart and liver, contain adult stem cells. These cells can differentiate into most cells of the body in which they are located. Adult stem cells are specialized cells replace the dead, since most specialized cells are incapable of natural reproduction. However, adult stem cells in most organs can not provide a complete replacement of the cells in the case of the massive damage in a number of diseases, although researchers are working to change this. Also of note is that adult stem cells are not pluripotent: Unlike embryonic stem cells, they are not able to grow into any cell of the body. The unique properties of embryonic stem cells is difficult to use for medical purposes. Ideally, patients who needed treatment for stem cells would have to get their own, genetically identical stem cells, because then they will not be attacked by the immune system of the patient, as foreign. However, embryonic stem cells, there are only a short period of time, namely during the first two weeks after conception. In addition, stem cells from embryos that are used for programs fertilization in vitro, to be genetically different from the patient's cells, which increases the risk of rejection of the immune system, and thus to suppress the immune response will require potentially toxic treatments. The use of embryonic stem cells is also fraught with ethical issues, as some people believe that an embryo can be implanted with the potential to make it developed into a fetus has the moral status of the person and therefore it can not be destroyed, no matter how great a benefit it could someone would bring. In 2001, President Bush limited federal funding for the then existing embryonic stem cell lines, that is, government money is not allowed to spend on studies, which implied the destruction of embryos. However, the newly-elected U.S. President Obama said that he will change the policy of the Government in the field of research. A possible solution to overcome such difficult obstacles, is the proposal of the Japanese researchers. They asked a simple, albeit non-standard question: can I get a specialized cell back to an embryonic stem cell, or even in cells with the exceptional properties that have embryonic stem cells? In each cell there are genes predetermine the structure and functions of each particular cell. Although all human specialized cells, like embryonic stem cells, have the exact same set of genes in each cell type "on" different genes. In other words, embryonic stem cells are transformed into specialized cells because certain genes are "switched on", while others "turned off." In 2006, a team of researchers at Kyoto University led by Shinya Yamanaka, used a powerful and relatively new technology to determine which genes are "on" and which are "off" in a specific cell type. Using this technology for research on embryonic stem cells and specialized cells, Yamanaka's team identified a number of genes in mice, which were always "on" in embryonic stem cells, but not in specialized cells. Then in late 2007, a group Yamanaka with a group of American scientists led by James Thomson of the University of Wisconsin and George Daley of Harvard, testified that the "inclusion" of four genes in human skin cells resulted in reversion of these cells into cells resembling embryonic stem cells. They called these new cells induced pluripotent stem cells (iPS). Like embryonic stem cells, iPS cells had the ability to transform into any type of specialized cells, as well as self-reproduction to an infinite number of copies. Thus, has become theoretically possible for anyone to create their own stem cells that are genetically identical and have all the potential to own long-lost human embryonic stem cells. In addition, the adult cells to be transformed into iPS cells can be easily obtained by biopsy of the skin or other surface tissues. And, very importantly, iPS cells can be generated by avoiding the creation and destruction of embryos, which allows you to bypass the moral barriers to the use of embryonic stem cells. However, it should be noted that, despite the importance of such a breakthrough in this area, therapy using iPS cells is still not a prospect near future. Still need to find answers to important questions and develop new technologies. The ability of cells to turn into any type of cell in the laboratory does not guarantee that using such cells can be successfully treated animal or human disease in the experiment. However, Rudolf Jaenisch testified that because iPS quite successfully treated sickle cell anemia in mice and Parkinson's disease in rats. However, the treatment is effective in rodents, do not always work in humans, however, they are often still active. It should also be noted that two of the four genes that were originally used to create iPS cells, are oncogenes that could turn iPS cells into malignant cells. In addition, for the transfer of the four genes in specialized cells used a retrovirus, which also carries a risk of becoming iPS cells into malignant cells. However, in late 2008, scientists reported that iPS cells can be created without the use of both oncogenes and retroviruses. In 2009, many laboratories are working on the modification of existing technologies to create iPS cells to make them as safe and effective. Another potential problem: how iPS cells created in the laboratory, safely move into the affected organ located inside the body? And if we can move them back if they can harmoniously "worked" with the healthy cells of the body? These questions are important and they do not have an answer. One of the facts that scientists have learned through the use of bone marrow transplantation (a type of stem cell therapy, is widely used for 30 years), is that the cells injected into the bloodstream, find their way to the appropriate place in the body and, once there, can respond to the body's own cells that surround them, starting to work in harmony with them. However, for certain organs is not so simple. For example, the heart. Suppose that due to myocardial infarction millions died of myocardial cells. After that, the patient's bloodstream introduced millions created iPS cells. Will they find a way to your heart? And even if found, it will take a correct position, and whether in the long term decline in unison with the unaffected healthy cardiomyocytes? If not, whether this will lead to arrhythmia? If these cells, in addition to heart, get into another body, it will not cause harm? The only way to find the answer to these questions - is the way of trial and error, first in animals and then in humans. In addition to treatment, iPS cells can also help to find the cause. Several research groups from Harvard created iPS cells based on the tissues of patients with different genetic diseases, including Parkinson's disease, Huntington's disease and type 1 diabetes. Because iPS cells can reproduce indefinitely, it allows you to create and study cells with genetic defects that determine the disease. The researchers also asked the question, whether there will be an opportunity to transform one type of specialized adult cells into iPS cells without creating another. This is considered unlikely until August 2008, when a team of scientists from the Harvard-led Douglas Melton transformed pancreatic cells not producing insulin, insulin-producing cells in live mice, which allowed to treat diabetes in this mouse. According to the materials of foreign publications prepared Volodymyr Pavlyuk