Researchers have succeeded in turning mouse skin cells into embryonic stem cells

It is possible that in the future the method will be improved and become safer, something that will bring closer the day when we can cure diseases with the help of cell transplantation

Yonat Ashhar and Noam Levithan, Galileo

The cells in our body have clear roles: a bone cell differs in its structure and function from a muscle cell, a liver cell or a brain cell. But all these cells developed from one cell - the fertilized egg. At the beginning of the embryo's development, all its cells are embryonic stem cells capable of becoming any cell and creating all the tissues and organs in the adult body. These are very special cells: after a cell has become a mature muscle cell, for example, it can no longer change and become a kidney cell. Only the embryonic stem cells have the potential to make all the cells in the body.
Due to this feature, stem cells have received intensive research in recent years. Such cells were produced from human embryos (at the stage when an embryo is nothing more than a ball of cells) created during fertilization treatments - in such treatments many embryos are always created, and only a part of them is inserted into the uterus. The scientists involved in the field hope to turn these cells, with the help of appropriate treatment in the laboratory, into desired cell types, and perhaps even into whole organs. In this way, it will be possible to test the response of the cells to drugs without trying them on humans, and also to transplant cells into humans - for example, if it is possible to produce pancreatic cells that produce insulin, it will be possible to cure diabetics with their help. Perhaps one day it will be possible to develop a functioning liver or kidney in the laboratory, for transplantation.
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This research still involves many problems, both practical and ethical. From a practical point of view, even if it would be possible to produce an organ in a laboratory, there is still the obstacle of transplant rejection. It will be very difficult to find genetically suitable stem cells for a patient waiting for a transplant. From an ethical point of view, the method includes the destruction of embryos for the purpose of producing cells, and there are many - especially in the United States - who oppose this, although a large part of the embryos that are not implanted in the womb are eventually destroyed anyway.
The best solution would be to produce embryonic stem cells from adult cells - that way embryos would not be destroyed for research purposes, and it would also be possible to take cells from a sick person and produce stem cells from them. An organ grown from these cells will be 100% genetically compatible with the person in which it will be transplanted.
And here, within one week, studies were published by three research groups that succeeded, each separately, in producing embryonic stem cells from mature skin cells of a mouse. Nimet Maharli (Maherli), Rupa Sridharan (Sridharan) and other researchers from Harvard University and the University of California published their research in the journal Cell Stem Cell; And Marius Wernig and his colleagues from the Massachusetts Institute of Technology and Keisuke Okita and colleagues from Kyoto University in Japan published their research in the same issue of "Nature".
The three groups followed the same method and reached very similar results. With this method, the skin cells are made to produce four different proteins that are not normally active in these cells. These proteins work naturally in stem cells, and are responsible for the production of many more proteins, which give these cells their special potential. Insertion of the four proteins artificially into mature skin cells causes a change in their properties, so that they become cells almost identical to embryonic stem cells.
The three groups conducted tests for the cells they created: the researchers examined the shape of the cells, which genes are expressed in them, chemical changes in DNA typical of sorted cells, the reaction of the cells to various chemicals, and more. In all respects, the cells behaved just like original embryonic stem cells.
The ultimate test was to create a normal embryo, which would develop into an adult mouse, from these cells - so it would be possible to show that the cells produced in the laboratory are indeed capable of creating all types of cells. All the groups succeeded in creating mice in which some of the cells were originally stem cells produced in the laboratory, thus proving that these were indeed stem cells for all intents and purposes. Wernig's group even managed to create a mouse exclusively from these cells, after injecting them into a suitable environment to create an embryo - the perfect proof that these are cells with unlimited potential.
Will this start a new era, where doctors will collect some skin cells from a patient, in order to grow cells to replace the damaged cells in his body? Not yet. First, the method currently works in mouse cells, not human cells. All three laboratories - and presumably many more - are trying to solve this problem, and may need to use more than four proteins. Yamanaka, the head of Okita's laboratory and the man who developed the method, estimated in an interview with "Nature" that this breakthrough would not take more than a year.
Besides that, even if such human cells were present, they cannot currently be transplanted into a patient. The proteins artificially introduced into the cells cause them to behave unexpectedly, and as a result about 20% of the mice produced by this method developed cancer. The method by which the cells are made to produce the proteins is also problematic - it involves the use of retroviruses, and is not considered safe. However, these studies certainly constitute a significant breakthrough and will probably lead to a wave of experiments that were not possible before. One of the possibilities, when they succeed in producing human cells, is to take cells from people with diseases such as diabetes or Parkinson's, turn them into stem cells, and grow pancreatic or brain cells in the laboratory from these stem cells, while monitoring the molecular changes that occur in the cells during their differentiation. In this way, they will be able to create diseased cells that are identical to the diseased cells in humans, try drugs on them, check the development of the disease and the effect of various factors on it, and more.
It is very possible that in the future the method of creating embryonic stem cells will be improved and become safer, which will bring closer the day when we can see the cure of diseases with the help of cell transplants. In the meantime, the researchers call not to neglect the "classic" research, in stem cells extracted from embryos.