id=”inContext_disabled”> 2013-05-17 16:50
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Get the first cloned human embryo is an important event for the basic sciences, but its practical relevance to medicine is problematic due to technical and ethical – told PAP MD Maciej Wiznerowicz from.
scholar referred in this way, the results of a team of scientists from Oregon Health & Science University, which were published May 15 in the journal, Cell. “Researchers of the Centre for the first time succeeded in sklonowana? human stem cells by nuclear transfer from somatic cell. late 90s, this method also served to clone Dolly the sheep.
“Scientists depend primarily on demonstrating that it is possible to clone a human embryo from mature cells, and understanding the molecular mechanisms responsible for this process. This is important from the point of view of fundamental science” – told PAP MD Maciej Wiznerowicz that conducts research on human stem cells at the University of Medical Sciences. University of Medical Sciences in collaboration with Poland Cancer Centre in Poznan, under the Welcome Foundation for Polish Science.
recalled that the first report of a similar human embryonic cloning by Korean scientists, published in 2004, the weekly, Nature ‘, turned out to be untrue.
,, Now U.S. researchers have optimized the previous protocols in the laboratory received the clones human embryos at a very early, three-day stage of development. Then, from these embryos obtained in laboratory culture embryonic stem cells. These cells have the potential to transform itself into all the cells of the adult human body “- said Dr. Wiznerowicz.
estimated that obtained through cloning, stem cells could be used in regenerative medicine – to repair damaged tissues and organs, such as heart after a heart attack or brain stroke. However, the method of cloning involves technical limitations and ethical considerations.
, is now much more sophisticated method of obtaining stem cells for this purpose is the creation of. induced pluripotent stem cells (in English with induced pluripotent stem cells, iPSCs). IPSC cells and a method of obtaining them are described for the first time in 2006 and already in 2012 for the study of them were awarded the Nobel Prize “- said Dr. Wiznerowicz. Stressed that the current experience with the use of lead thousands of laboratories around the world, and next in Japan is expected to begin clinical trials on patients.
iPSC cell procurement method is to convert adult human cells into stem cells using common methods of genetic engineering. IPSC cells are fully pluripotent, meaning that they can be obtained adult cells of all tissues of the body.
In contrast cloning stem cells requires the derivation of human oocytes and the production of human embryos, which are then destroyed in order to obtain stem cells.
,, In our laboratory we routinely obtain human induced pluripotent stem cells from skin fibroblasts of donors and I can honestly say that this technology is very repetitive, relatively simple and can be a good source of human cells for use in regenerative medicine then “- said Dr. Wiznerowicz.
In his view, the current state of knowledge can safely assume that the cells – such as nerve or heart muscle – derived in this way will work just as well as cells from a cloned human embryo.
,, So you may be wondering whether there is a need to deal with a method that raises many ethical controversies. On the other hand, until we have 100 percent confidence in clinical trials that induced pluripotent cells meet the expectations placed in them parallel testing of alternative methods can be beneficial and do not place restrictions here “- said Dr. Wiznerowicz.
Specialist noted, however, that the cloning of embryos is by far less efficient, but more complicated technically.
First, you need to have a volunteer who agrees to undergo hormonal stimulation (to come to an ovulation, or the release of an egg from the ovary) and then trying the egg collection procedure under ultrasound guidance in gynecological surgery. Later, these cells removed is their own nucleus (genetic material) and put a mature cell nucleus, most fibroblast of the connective tissue of the skin. In culture, developing human embryo, which at the blastocyst stage, which is a three-day pre-implantation in the uterus, it is destroyed. Obtained from the stem cells need to multiply, and then prove that there are no anomalies.
Induced pluripotent cells formed in the culture of fibroblasts of skin. This requires a small piece of skin. Following the genetic modification of cells are formed in the culture for about 3-4 weeks.
, practically from each donor goes to get the correct and fully functional iPSC cells with very high efficiency. In the case of cloning success rate is much lower and amounts to less than 10 percent. “- Said Dr. Wiznerowicz. Reason for this is that the time in which the highly specialized mature cell nucleus must be converted into the germ is the cloning of very short and is only a few days.
,, This is a very delicate procedure, and every slightest variation of the experimental conditions may interfere. That is why it is so difficult to get cloned mammalian embryos. Here is often a few hundred developing embryos can be considered fully valid, and many of them did not grow, “- said Dr. Wiznerowicz.
reminded that cloned Dolly the sheep just a few hundred samples.
In his view, the fact that it was easier to clone a sheep than a mouse and a human embryo may be due to the fact that it took a little research teams.
As the researcher, human cloning human stem cells is especially important for cognitive purposes. “Chance obtain a healthy adult organism, which is a clone of the donor is minimal and certainly was not the intention of the authors described work. Use of cloning techniques for the purpose of stem cells for regenerative medicine is problematic at this stage because of the severe limitations of technical and ethical” – summed up Dr. Wiznerowicz. (PAP)
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