A team of scientists from South Korea made the significant breakthrough. Stem cells that will be taken from the embryos will be used in the future for transplants in sufferers of diseases such as Alzheimer's.
concentration of sources
On the way to human cloning / a breakthrough in South Korea *
Seven years after Dolly the sheep: first cloning of a human embryo
By Yuval Dror
Scientists from South Korea have demonstrated for the first time that it is possible to clone human embryos and produce embryonic stem cells from them, which could be used for healing purposes. The scientists clarified that the purpose of cloning is not reproduction. The scientists took the genetic material found in one of the cells in a woman's body, and merged it with an egg taken from her, after the genetic material had been removed. After the egg began to divide, the embryos were grown for a few days and embryonic stem cells were extracted from one of them.
According to them, the perfection of the technology will allow scientists in the future to grow tissues and organs that will be implanted in the bodies of the people who donated the genetic material (men or women).
"This is definitely a breakthrough," said Hermona Sorek, professor of molecular biology from the Hebrew University of Jerusalem, yesterday. However, she noted, there is a long way to go before this technology can be used.
The cloning was carried out as part of a study conducted under the supervision of Dr. Woo Suk Hang and Dr. Shin Jung Moon, from Seoul National University. The results of the work, which will be published this morning in the scientific journal "Science", provide details on the best way to clone embryos. The conclusions were reached after the research group tried 14 different ways to perform the cloning. In the past, several research groups tried to clone human embryos and monkey embryos, but all attempts failed. For this reason, the success in cloning 30 human embryos and producing embryonic stem cells from them is considered a landmark. "This is the most advanced growth of a cloned embryo to date," Dr. Hang told the BBC.
And this is how it worked: the South Korean team received a donation of 242 eggs from 16 women. Among the eggs, 176 eggs were selected that seemed to have particularly good chances of going through the procedure. In addition, "cumulus" cells were taken from the women - mature cells that adhere to the egg and provide it with nutrition.
"It is likely that the choice of the cumulus cells was made after, in animal experiments, and especially mice, it turned out to be convenient to work with them," said Prof. Ruth Shelgi, vice president for research at Tel Aviv University and an embryologist who specializes in fertilization and early development. Dr. Moon told the "New York Times" that the cumulus cells are "glued" to the egg anyway, so they are easy to use.
The scientists refused to say how they were able to convince the women to donate so many eggs, a procedure that requires the use of hormones that increase the rate of their production.
In the USA, the "Advanced Cell Technology" company, which was also engaged in research on the subject, offered $4,000 to every woman who agreed to donate eggs, but only 19 eggs were donated. The company previously reported that it had succeeded in cloning embryos, but later it turned out that the egg only divided into six cells and then stopped. The South Korean scientists declined to say how they received such a generous donation, but noted that the donors were not paid.
At the beginning of the procedure, the genetic material found in each of the eggs was removed and replaced with genetic material taken from the nucleus of the cumulus cells of that donor. After some time, the egg "resets" the development clock of the adult cell, and reprograms it in such a way that it returns to its embryonic state. From this stage onwards, the egg behaves as if it had been fertilized by a sperm, and begins to divide. Allegedly, the dividing egg can be implanted in a woman's uterus, thus growing a cloned embryo (something that has never been successfully attempted). However, the law in South Korea prohibits cloning for the purpose of reproduction, and the process was stopped after six days of division - when the embryo reaches the stage known as "blastocyst". At this stage, the embryo has hundreds of cells from which embryonic stem cells can be derived.
Embryonic stem cells, unlike other cells, have not yet differentiated and "decided what they will be when they grow up" - that is, they can become any cell in the body's tissue (cartilage cells, skin cells, heart muscle tissue cells). In the current study, the scientists, for the first time, managed to reach this stage and grew 30 embryos - an extraordinary success rate. Of the 30, they managed to produce one line of embryonic stem cells. To prove that it is indeed embryonic stem cells that know how to differentiate into different tissues of the body, they were transplanted into a mouse.
The study provoked outraged reactions. Prof. Jose Kibli from the University of Michigan, who specializes in biotechnology and was a co-author of the article, told "Wired" magazine that he was asked back in June 2003 to review the research of his colleagues from South Korea. "It arrived like any normal e-mail message, but when I examined the results I almost fell off my chair," he said. Other scientists point to the shortening distance between cloning for research purposes and cloning for reproductive purposes.
Dr. Leon Kess, the chairman of the Council for Bioethics in the USA, called for the enactment of a federal law in the USA that prohibits the cloning of embryos for any purpose. The editor of the journal Science praised cloning for research purposes, but called for a global ban on cloning for reproductive purposes. "The results look promising", he said, but added: "It is important to remember that technologies that allow cells or tissues to be transplanted are in the early stages of development, and it may be years before it is possible to use embryonic stem cells for transplantation purposes."
Prof. Shelgi fears that the successful results of the research will lead to the promotion of procedures aimed at cloning for reproductive purposes: "If you show success, it's tempting to say 'let's go to the next step', and we know what the next step is: cloning for reproductive purposes." According to her, animal studies have shown that cloning for reproductive purposes creates many problems, such as the lack of expression of genes that are expressed in a normal pregnancy - but are not expressed in a pregnancy created by cloning. Therefore, says Shelgi, "it is not at all clear that the stem cells produced from the cloning procedure can be used."
Yuval Dror
Scientists: We have cloned human embryos
For the first time in history, researchers were able to create embryos and grow them in the laboratory * The researchers used a woman's eggs, without the need for fertilization by a man * The purpose of the experiment: finding cures for serious diseases, using embryonic cells
Alex Doron, Maariv, 13/2/04
The fertilization of the cloned cells, as photographed in the laboratory in South Korea. Photo: Reuters
Men beware - soon you may not be needed. Korean scientists succeeded in creating an embryo from eggs and genetic material taken from a woman only - without any need for a man to improve the woman. Scientists from the National University in Seoul, the capital of South Korea, succeeded in cloning human embryos. According to them, their research will help in finding new ways to cure serious diseases, using embryonic stem cells. The embryonic cells can be directed to create tissues for transplantation, without rejection from the body in which they are transplanted.
The details of the process were described in Science magazine by Prof. Wu Suk Wang and his 13 colleagues. In the process, an egg was not fertilized with a sperm, but reproduction by the method of nuclear transfer. The researchers took eggs donated from women, and instead of the nucleus of the egg cell, they injected genetic material taken from those women.
According to the researchers, 25 percent of the cloned eggs managed to develop to the blastocyst stage - an initial stage lasting only a few days in the development of the embryo. What was created could be implanted in a woman's womb, so that it would continue to develop into a human baby. But the goal of the researchers was to create embryo-like bodies that contain a mixture of different types of tissue - skin, muscles, cartilage, bone or nerve whose further development can be directed, in order to be implanted in a patient.
* "an impressive but ineffective process"
Prof. Yosef Itzkovits-Elder from the Technion School of Medicine in Haifa and director of the maternity department at Rambam, is the pioneer of scientific research in Israel on embryonic stem cells. In an interview with Maariv, he said yesterday that what the Koreans did was expected, and the achievement is that this technology was applied to humans for the first time, since all previous attempts had failed. "The process, as impressive as it may be, is ineffective," said Prof. Itzkovits-Elder, "quantitatively, it is about hundreds of attempts and a single success. There is also no certainty that the embryos, if they were implanted in the uterus - would even develop into a baby."
On the importance of the achievement, the Israeli scientist said that the work proved that the move was possible, "the medical consequences are far-reaching. In the future, it will be possible to take a skin cell from a Parkinson's patient, and create stem cells that will develop into new nerve cells that will be implanted in his body for healing. In other words, it will be possible to adapt a healing method to each of us with this technology based on the body's own substances."
First successful cloning of human embryos
Voila system!' 12/2/04
Scientists from South Korea succeeded for the first time in cloning 30 human embryos with the aim of using their cells in the future to treat diseases. Professor Woo Suk Huang and his team from Seoul National University were able to take the genetic material from normal donor cells and fertilize them with their own eggs. The research team said it used 242 eggs taken from 16 female donors.
From the developed embryos it is possible to produce stem cells that are able to adapt to any tissue in the body. The goal is to use the new cells to replace diseased cells in those suffering from diseases such as Alzheimer's. "Because the cells carry the donor's basic gene, after the process they can be transplanted without fear of rejection among people suffering from degeneration," said Prof. Huang.
Until now, no group has been able to clone so successfully and observe the development process up to such an advanced stage. "These are the most advanced cloned embryos produced to date," Huang told the BBC.
In the past there were claims by various researchers that they succeeded in creating a human embryo for the purpose of stem cell research, but it seems that this was not a real success. "Our breakthrough opens the door to the use of these developed cells in the field of transplants," Huang said. The full details of the research are published in the magazine "Science".
