For the first time, embryonic stem cells of rats were obtained

A new method for obtaining embryonic stem cells

Alexey Levin, Voice of AmericaThe staff of the Keck Medical School of the University of Southern California celebrated the upcoming New Year holidays with a message about a remarkable breakthrough in the field of the latest biotechnologies.

A specialist in neurobiology and cell biology, Ki-Lon Ying and his colleagues have published information about the production and reproduction of full-fledged embryonic stem cells of laboratory rats. They presented their results in an article that will appear in the journal Cell on December 26.

Embryonic stem cells, in the abbreviation ESC, are contained in fertilized eggs that have managed to make only a few divisions, the so-called blastocysts. During the intrauterine development of the embryo, ESCs give rise to specialized cells of all organs and tissues without exception. Cells with such a wide potential for subsequent transformations are called pluripotent.

Researchers have been trying for several years to use pluripotent cells to repair tissues damaged as a result of disease or accident. For example, there is every reason to hope that the transplantation of such cells will lead to the healing of a traumatic rupture of the spinal cord or the restoration of the necrotic area of the heart muscle affected by a heart attack.

At first glance, it may seem that the work of scientists from Los Angeles and their colleagues from Cambridge and the University of Edinburgh does not shine too new. After all, mouse ESCs have been isolated and cultivated since the early 80s of the last century. Methods of obtaining human ESCs are also well-developed, they have been successfully used for ten years. Currently, hundreds of viable cultures of such cells are supported in laboratories in various countries on nutrient media.

However, experiments with human embryonic cells cause sharp protests from many influential social groups and church circles both in the United States and in other countries. Experiments with mouse ESCs, on the contrary, do not excite any negative emotions. But mouse physiology is very different from human physiology, so many of the results of such studies cannot be transferred to the human body in any way.

And that's where the rats can help. In many ways, these animals are much closer to humans in their biology than mice. Using the ESCs of these animals, it would be much better to investigate the origin of a variety of human diseases, for example, diabetes, arthritis and cancer. In addition, rats are closer to humans than mice, and by characteristic reactions to many medications. Therefore, for many years now, scientists have been trying to find ways to obtain viable rat ESCs.

However, this task turned out to be a very hard nut to crack. For a number of technical reasons, methods for extracting mouse ESCs simply do not work on rats.   Therefore, so far all attempts of this kind have led to nothing.

Researchers from Los Angeles have succeeded with the help of chemical weapons. Before extracting stem cells from the surrounding cell mass of blastocysts, they injected into it molecules of substances that inhibit the activity of three specific genes.

This operation blocked stem cells from receiving signals that would force them to enter the path of divisions leading to gradual transformation into specialized cells. As a result, the isolated cells retained their pluripotency and thus remained full-fledged ESCs. Scientists multiplied them on a nutrient medium and created a viable colony (or, as experts say, a line) from them.

By an interesting coincidence, Dr. Ying and his colleagues published their results in the last days of the Chinese year of the Rat. In the same issue of Cell magazine there is an article by employees of British universities, who (also with the participation of Ying) obtained similar results. So the cherished barrier of obtaining rat-ESCs, apparently, can be considered taken.

It is possible that something more has actually been done. Obtaining ESCs using a cocktail of molecules that block cellular differentiation is a very new technique. It was first demonstrated in action on mice only this year. Now it has been proven that it works great for rats as well. It is possible that with its help it will be possible to isolate and preserve embryonic stem cells of other mammals, including farm animals.

But that's not all. Researchers are already thinking about using a new technique to obtain new lines of human ESCs. It cannot be excluded that they will differ in some significant way from similar lines created by traditional methods. If this hypothesis is confirmed, science will receive valuable information about the mechanisms of genetic programming of embryonic cells.

Portal "Eternal youth" www.vechnayamolodost.ru25.12.2008