Hybrid embryos: the direction is closed?
Chimeric embryos turned out to be useless for scienceEmbryos obtained by transferring the nucleus of an adult human cell into the cytoplasm of an animal egg cell turned out to be unsuitable for obtaining viable stem cells.
Such conclusions were reached by employees of the American company Advance Cell Technology, whose research was published in the journal Cloning and Stem Cells.
For research in the field of cloning and embryonic stem cells, a large number of donor eggs are needed, the extraction procedure of which is unsafe for the health of female donors. In addition, therapeutic cloning, as a result of which full-fledged human embryos are formed, which are supposed to be used as a source of various types of stem cells, is legally restricted in most developed countries. These circumstances explain the interest of scientists in alternative sources of stem cells, in particular, hybrid embryos, for which mammalian eggs available in unlimited quantities are used.
In the Advance Cell Technology study, the properties of hybrid embryos obtained from the eggs of cows, rabbits and mice were studied. They were compared with human embryos obtained by in vitro fertilization, as well as with embryos developing from human eggs into which the nuclei of human somatic cells were transferred. Hybrid embryos were close to human in shape and frequency of cell division, and genetic studies have shown that the nuclei of their cells do contain human DNA.
At the same time, the vast majority of genes regulating the processes of development and differentiation of embryonic cells in the early stages of development did not function in hybrid embryos. This means that the cells obtained from such embryos will differ in their properties from human embryonic stem cells, which makes their use in scientific and medical research meaningless.
The creator of the world's first cloned mammal, Dolly the sheep, and the publisher of the journal Cloning and Stem Cells, Ian Wilmut, called the results of the study important and at the same time disappointing. “These data mean that obtaining stem cells suitable for sick people in this way (from hybrid embryos) is impossible,” the scientist says.
Medical News Today: Animal Eggs Not Suitable Substitutes To Produce Stem Cells
Portal "Eternal youth" www.vechnayamolodost.ru04.02.2009