Statement

Last week South Korean scientists reported successful therapeutic cloning of human beings. They allegedly failed to grow three dozen embryos until the moment when they consisted of about a hundred cells, and from one embryo to obtain material for further research.

In the experiment, was obtained 30 cloned embryos, but only one of them managed to get stem cells. Further experiments with them have shown that the resulting line of embryonic stem cells can give rise to various tissues and organs. It is in this perspective of their use in medicine - you can grow organs for humans from his own cells.

Recall that the individual stages of the experiment, described in the latest brand name viagra issue of the journal Science, were made earlier. For example, in 2001 a team of American experts from the company Advanced Cell Technology has received a human embryo, but also destroyed it at an early stage of development. Constantly conducted experiments on stem cells from an adult organism.

What is actually an experiment consisted of South Korean scientists? How realistic it seems today, human cloning? His opinion on the "loud" statement on cloning human embryos express Elena Zakharova, embryologist Medical Clinics reproduction "MA-MA and Senior Researcher, Laboratory of Genetics of IOGen Sciences, Ph.D., embryologist Medical Clinics reproduction" MA-MA "Dmitry A. Isayev.

Cloned human embryo - an embryo produced not by the merger of sperm with an egg, and as a result of transplantation of the egg, previously devoid of its own genetic material, the nuclei of somatic human cells. Such an embryo genetically identical to the person from whom the somatic cell was taken. If the cloned embryo is transferred into the woman's uterus, it is theoretically possible (proof of this yet) to get the pregnancy and the birth of a human clone.

Another, more practical and promising option of using cloning technology to obtain embryonic stem cell lines from cloned human embryo (blastocyst) with the aim of therapeutic cloning. Embryonic stem cells can give rise to all cell types shown in our body. Perhaps scientists will never be able to grow these stem cells in the brain or heart, but of course, cell therapy will find its place in medicine of the future.

The aim of the present study was to obtain embryonic stem cell lines from cloned embryos, rather than the birth of a human clone. In this statement we are talking about therapeutic cloning.

To obtain cloned embryos have been used 176 oocytes. In each oocyte, after removal of their own genetic material was transplanted somatic follicular cells (the cells surrounding the oocyte during its maturation in the ovaries). Thus, all cloned embryos had a female genotype and had a genetic copy of the woman, the follicular cells which have been used. Only 25% of cloned embryos could develop to the blastocyst stage, and only 20 of them were able to use for stem-cell lines. As a result, large-scale experiment was obtained and studied only one (!) Line of embryonic stem cells genetically identical to the donor organism.

Although it is too early to talk about the widespread use of cloning technology (as long as it is only the first positive result), presented work is elegant and beautifully performed fundamental research, the results of which will undoubtedly contribute to the understanding of complex biological processes.

In the latest issue of the online version of the famous journal Science published an article by South Korean scientist Woo Suk Hwang and colleagues about how to obtain embryonic stem cells (ESCs) from the "cloned" human embryo (Hwang et al., Evidence of a Pluripotent Human Embryonic Stem Cell Line Derived from a Cloned Blastocyst / / Science. 2004 Feb 12).

Depending on the goal-setting to distinguish between therapeutic and reproductive cloning. The purpose of reproductive cloning is the creation of "new" body-clone - a genetic copy of the living, or even long-dead creatures, in this case - the person. Therapeutic cloning aims to create an external supply of human ESCs for possible future treatment of diseased or damaged organs through stem cell therapy. Reproductive cloning is of great scientific and practical importance for the livestock, but when it comes to human cloning - unanimously condemned by the public and the overwhelming majority of scientists. Therapeutic cloning is accepted by scientists and physicians, but with a very significant reservations, as can be achieved in different ways:

1) transplanting the nuclei of cells in the adult donor eggs and the release of ESCs from embryos obtained in this manner;
2) allocation of ESCs from abortive material;
3) separation from the body's cells, such as bone marrow, and "treatment" of a state of ESCs;
4) separation of cells from the developing embryo.

Two recent fashion do not cause moral objections, but at least for now, technically unfeasible.

In the article scientists from Seoul National University, we are talking about therapeutic cloning. Prior to its publication, this sensational writing team for a long time conducted similar brand name drugs experiments with embryos of cattle and pigs. Then carried out experiments similar to those by P. Zavos.

For obtaining human ESCs Dr. Hwang and his colleagues used the "classic" approach: donor eggs from a remote pre-core nucleus of body cells transplanted adult human embryos cultured to the blastocyst stage and then extracted stem cells from them. This attracted the attention of the media - exactly the same way by reproductive cloning! No need to rush to condemn Korean scientists - they themselves are a very responsible attitude to the results of their experiments, in addition to South Korea cloning is prohibited.

Efficiency of obtaining ESCs from cloned blastocysts rights in the work of Korean scientists is low, so that to the practical application of the results of such experiments in regenerative medicine is still very far - despite the clearly designated target at the moment they have only academic value. At the same time, some three dozen cloned blastocysts - this is a sufficiently large number, making you more seriously the claims of the birth of cloned children.

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