MEDICINE: by Peter WestmoreNews Weekly
Dolly's creator abandons therapeutic cloning
, December 8, 2007
Professor Ian Wilmut's decision to abandon embryonic stem-cell research has sent shock-waves through the cloning community.Professor Ian Wilmut, the medical researcher who pioneered animal cloning and created Dolly the sheep, has announced that he will abandon research aimed at producing human embryonic stem-cells through cloning, i.e., so-called "therapeutic cloning".
Professor Wilmut is chair of reproductive biology at the University of Edinburgh and director of the Scottish Centre for Regenerative Medicine.
Like Australia's Professor Alan Trounson, his background is in animal health. He obtained a B.Sc in agricultural science at the University of Nottingham before studying at the University of Cambridge, where he was awarded a Ph.D in 1971. His subsequent research in Cambridge led to the birth of the first calf from a frozen embryo in 1973.
Professor Wilmut's recent decision has sent shock-waves through the cloning community, which had claimed that "therapeutic cloning" is the answer to everything from Alzheimer's disease to renal failure.
He said he was abandoning therapeutic cloning in favour of a technique invented by a Japanese medical scientist, Professor Shinya Yamanaka from Kyoto University, who has succeeded in converting adult cells from mice into "pluripotent" stem cells.Killing donor embryos
If the technology is demonstrated in human beings, it will provide the means of supplying a large range of compatible stem cells without the ethical problems of cloning and stem-cell harvesting which kills the donor embryos.
Professor Wilmut is enthusiastic about Professor Yamanaka's research. He said that the new approach was "easier to accept socially" as well as being "extremely exciting and astonishing".
His decision to abandon human cloning is particularly significant because he was given a licence to create human embryos for research purposes two years ago. One observer commented that "his announcement could mark the beginning of the end for therapeutic cloning, on which tens of millions of dollars have been spent worldwide in the past decade".
Professor Wilmut said, "Before too long, we will be able to use the Yamanaka approach to achieve the same, without making embryos."
Professor Wilmut's change of heart conceded that the Yamanaka approach avoids the ethical challenge of cloning through somatic cell nuclear transfer, but he had previously written that he does not regard an early embryo as a human being.
In a book on the subject, After Dolly: The Uses and Misuses of Human Cloning,
he said, "When I look at a sheep blastocyst [early embryo] under the microscope, I do not think of it as a sheep. Nor would I think of babies when I gaze at a human blastocyst, though I accept that some couples undergoing IVF treatment are attached to their early embryos."
He added, "Nor does a fertilised egg created by scientists in itself have any potential to become a person without human intervention ... [but] the main reason why I do not regard a blastocyst as a person is that it has no mental life."
The practical effect of Professor Wilmut's decision could be seen, first, in the United States, where both houses of Congress, now controlled by the Democrats, have passed bills which overturn President George W. Bush's refusal to allow federal funding for destructive human-embryo research.
The President has vetoed these bills, but the Democrats had indicated that they would persist.
While Professor Wilmut's decision seemed to come like a bolt from the blue, there have been a number of scientific studies confirming the Japanese research over the past year or so.
A team from Massachusetts Institute of Technology (MIT), led by the prominent stem-cell scientist Rudolph Jaenisch, replicated the Japanese experiments, and after making further refinements, produced cells that appeared to pass all the critical tests of so-called "pluripotency" - the ability to be transformed into a large variety of cell types - which scientists so value about stem cells.
Last May, the American College of Pediatricians called for an end to embryonic stem-cell research and recommended the exclusive support of already proven adult stem-cell research.
"Not only does embryonic research require taking the life of human embryos, it also prolongs needless suffering by delaying the development of more promising adult stem-cell treatments and cures," stated Michelle Cretella, MD, fellow of the American College of Pediatricians (www.acpeds.org).
The American College of Pediatricians added, "Adult stem cells are now routinely used in certain forms of cancer therapy. Over the last decade, these cells have been used to successfully treat spinal-cord injuries, heart failure, Parkinson's disease, diabetes and dozens of other conditions in human trials."
In contrast, there have been no effective therapies developed with embryonic stem-cells.
Last June, two leading scientific journals, Nature
and Stem Cell
, published papers by three separate research teams on successes in turning mouse skin cells into genuine pluripotent stem cells.
Professor Wilmut's decision reinforces the point that ethical stem-cell research is also the only effective one.- Peter Westmore