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First Human Cloning Performed by South Korean-U.S. Team SEATTLE, Washington, February 13, 2004 (ENS) - For the first time, researchers have reported the development of human embryonic stem cells from a cloned human blastocyst, a hollow microscopic ball of 50 to 200 cells. These cloned cells are potentially capable of becoming any cell in the human body, and the researchers say they are interested in medical advances using this characteristic of the cloned cells rather than in creating a cloned human being. Evidence of the first human cloning success was announced Thursday at the 2004 Annual Meeting of the American Association for the Advancement of Science (AAAS) in Seattle, and published by "Science" magazine online. Embryonic stem cells have been produced with cells from mice, but this is the first cloned creation of human stem cells. The successful team of scientists - 14 South Koreans and one American - led by Woo Suk Hwang of Seoul National University, used more than 240 eggs from 16 different women to create 30 blastocysts - the hollow balls of cells that can be used as the source of stem cells. The human stem cells were harvested from a blastocyst produced by transferring the nucleus of a non-reproductive somatic cell, containing a woman's genetic blueprint, into a nucleus-free egg from the same donor. Following this transfer, factors within the host egg's exterior reprogrammed its new nuclear contents by activating versatile embryonic genes, while silencing the more limited adult somatic cell genes. Researchers were then able to collect human embryonic stem cells from the resulting cell mass inside the cloned blastocysts. No contribution from a male was needed for the cloning process.
Woo Suk Hwang led the scientific team that cloned the first human embryonic stem cell line. (Photo courtesy Korea Times)Hwang and colleagues developed the stem cell line, SCNT-hES-1, after collecting 242 eggs from 16 unpaid volunteers who had signed informed consent agreements. From these eggs, scientists then cultured 30 blastocysts to obtain 20 suitable inner cell masses.Other researchers have tried but failed to accomplish this feat. Advanced Cell Technology Inc. of Worcester, Massachusetts said in 2001 that its research towards developing a stem cell line failed when the cloned embryos died before researchers could extract stem cells. Hwang and his team attribute their success to the use of extremely fresh donor eggs, strict timing protocols, and a special method for gently extruding rather than suctioning the "DNA spindle complex" from eggs. Suctioning the DNA may damage spindles, possibly causing chromosomal defects, they noted. Speaking in Seattle at the AAAS meeting, Hwang said, "Because these cells carry the nuclear genome of the individual, after differentiation they could be expected to be transplanted without immune rejection for treatment of degenerative disorders." "Our approach opens the door for the use of these specially developed cells in transplantation medicine," he said.
Human stem cell research is a rapidly emerging field. These cells are being studied at the University of Washington School of Medicine, which with the Fred Hutchinson Cancer Research Center, will establish a federally funded Exploratory Center for Human Embryonic Cell Research. (Photo courtesy University of Washington School of Medicine)Hwang and Shin Yong Moon, director of Korea's Stem Cell Research Center, told fellow scientists gathered in Seattle that reproductive human cloning is banned in South Korea, a law they support. In fact, they see a need for similar laws in other countries."Science" Editor-in-Chief Donald Kennedy stressed the value of cloned human cells in treating diseases such as diabetes, osteoarthritis, or Parkinson's by producing replacement cells unlikely to trigger immune system rejection. This research is not the first step toward the creation of a human clone, Kennedy emphasized. "There is widespread consensus among all responsible, mainstream scientists - including the authors of this paper and AAAS, publisher of "Science" magazine - that any attempt to clone a human being would be highly dangerous and wrong, and therefore, all reproductive cloning should be banned," Kennedy said. "But, the generation of stem cells by somatic cell nuclear transfer methods involving the same individuals may hold promise for advances in transplantation technology that could help people affected by many devastating conditions," he said. The scientific team that achieved the first human cloned cells is made up of 14 Koreans - from Seoul National University, Mizmedi Hospital in Seoul, Gachon Medical School, Hanyang University, and Sunchon National University, as well as one American, Dr. Jose Cibelli of Michigan State University's Animal Science Department who helped produce the first genetically altered cows through cloning.
Dr. Jose Cibelli of Michigan State University's Animal Science Department (Photo courtesy MSU)Dr. Cibelli has been involved in human cloning experiments for at least five years. In 1998, when Cibelli was vice president of research at Advanced Cell Technology, one of Cibelli's own skin cells was combined with a cow's egg from which the genes had already been removed.The genes activated and the egg began to divide in the normal way up to the 32 cell stage at which it was destroyed. If the clone had been allowed to continue beyond implantation in a human womb, it would have developed as Cibelli's identical twin. On his Michigan State website, Cibelli says, "A number of different laboratories, including our own, have demonstrated that a somatic (body) cell, once fused with an egg, is capable of generating not only stem cells but a whole new organism as well. Interestingly, we still do not comprehend how this is possible." However exciting the possibility of learning more about cloning is to Cibelli and his colleagues, some Americans believe the experiments have gone far enough. Carrie Gordon Earll, senior policy analyst for the Christian nonprofit organization Focus on the Family, said today that a "moral line" has been crossed and a new "moral ethic" is being created by Hwang and his colleagues. "Scientists conducting and advocating for human cloning as a means of deriving embryonic stem cells for research are crossing a moral line in their exploitation of the human family," Earll said. "As a result, a new moral ethic is being embraced: the more vulnerable a human is, the more acceptable it is to destroy." "Creating human life through cloning for the sole purpose of its destruction by extracting stem cells is nothing short of scientific cannibalism, consuming and devouring our young for speculative scientific gain. It is immoral and unnecessary. The real advances in regenerative medicine are already evident in successful trials and actual therapies utilizing non-embryonic stem cell sources such as bone marrow, umbilical cord blood, the pancreas and brain. No human life is destroyed in collecting these cells. In Earll's view, cloning embryonic stem cells is in fact cloning human beings because if they are implanted in a womb and allowed to grow, a fetus might result. "Proponents of human cloning for embryonic stem cell research are so desperate to gain public approval that they purposefully misrepresent what is taking place, insisting that they are not cloning human beings," she said. Earll urged Congress to pass a comprehensive ban on all human cloning as seen in the "Human Cloning Prohibition Act of 2003" passed by the House of Representatives last year. Hwang's cloning research paper published by "Science" is online at: http://www.aaas.org/news/releases/2004/hwang-02-13-04.pdf The President's Council on Bioethics website on cloning is found at: http://bioethics.gov/topics/cloning_index.html The World Health Organization website on cloning is online at: http://www.who.int/ethics/topics/cloning/en/ |
