American scientists announced the cloning of the first human embryo earlier this week, emphasising that they had done it for therapeutic purposes only. It comes in the week that the British government pushed through emergency legislation to ban reproductive cloning after the recent high court judgment that no law existed to prevent cloning of human embryos (24 November, p 1203).
Results reported on 25 November by Jose Cibelli and colleagues in the on-line journal e-biomed: the Journal of Regenerative Medicine (www.liebertpub. com/ebi) describe how human embryos were created by somatic cell nuclear transfer (the method used for Dolly the sheep four years ago). DNA from human skin cells were placed within enucleated human embryos and then exposed to chemical and growth factors.
According to the paper, the most developed cloned embryo grew to six cells after being cultured for a week. Two of the eight somatic nuclei divided into just four cells. To harvest stem cells for medical use an embryo would need to reach a minimum of 64 cells.
Volunteers who provided their skin cells to be cloned had diseases such as diabetes or spinal cord injury. One donor, 40 year old Dr Judson Somerville, hoped that stem cells from his own cloned embryo would one day end his paralysis caused through a cycling incident and allow him to walk his daughter down the aisle when she married.
The scientists who carried out the research—at the US company Advanced Cell Technology, Massachusetts—were confident that these results proved the technique viable. They claimed that within a decade cloned embryos could have their stem cells harvested to treat a wide range of conditions.
Robert Lanza, the company's vice president, has been quoted as saying: “This work sets the stage for human therapeutic cloning as a potentially limitless source of immune-compatible cells for tissue engineering and transplantation medicine.
“Our intention is not to create cloned human beings, but rather make lifesaving therapies for a wide range of conditions, including diabetes, stroke, cancer, AIDS, and neurodegenerative disorders such as Parkinson's and Alzheimer's disease” (Guardian Nov 26:1).
Such projects will probably soon be illegal in the United States. In August the House of Representatives, with the backing of President Bush, agreed to make it a federal crime to produce cloned embryos for research (18 August, p 357). Approval by the Senate has been delayed because of the events of 11 September.
In the United Kingdom the government wishes to permit therapeutic cloning but outlaw reproductive cloning. At the time the BMJ went to press, emergency legislation had completed all its stages in the House of Lords and was due to be introduced into the House of Commons. The Human Reproductive Cloning Bill makes it a criminal offence to “place in the womb of a woman a human embryo that has been created other than by fertilisation.”
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HO/AFP
Michael West, president of Advanced Cell Technology