WASHINGTON — In a development hailed as a breakthrough by those on both sides of the global debate over the morality of allowing life-destroying embryonic stem-cell research, scientists in Japan and the United States have “reprogrammed” adult skin cells into becoming “pluripotent” stem cells.
Such stem cells hold the promise of delivering all of the potential benefits of embryo-derived cells — without sacrificing any human life.
“I think this is really what we have been dreaming about,” Dr. Markus Grompe, director of the Oregon Stem Cell Center and a member of the board of directors of the International Society for Stem Cell Research, said about the new research findings.
Legionary Father Thomas Berg, director of the Westchester Institute for Ethics & the Human Person, called the research breakthrough “a win-win” for everyone.
“This is a great moment for science, a great moment for ethics, which has insisted on the protection and the dignity of the human embryo,” said Father Berg, who is a member of the ethics committee of New York’s Empire State Stem Cell Board, which oversees $600 million in research funding.
Pluripotent stem cells can develop into any tissue in the human body. Until now, early-stage embryos that are killed and harvested for their stem cells have been the only source of such cells.
Adult stem cells can develop into new human tissue, but they lack the ability to change into all body tissues and therefore can’t provide all of the same research advantages and potential therapeutic benefits.
But on Nov. 20, two scientific papers published in Science and Cell magazines detailed a new way to generate pluripotent stem cells. By introducing small amounts of viral material into human skin cells, research groups in Wisconsin and Japan have triggered their transformation into “induced pluripotent state” cells.
This “direct reprogramming” process appears to address all major moral and scientific problems associated with embryonic stem cells. First, no human life is destroyed, because the cells are taken from the skin of healthy adults in a minor medical procedure that causes little inconvenience.
And the reprogrammed cells do not become new embryos, unlike the result of “somatic cell nuclear transfer,” a procedure used to create cloned embryos to be used in stem-cell research.
From a scientific point of view, the new process is far simpler than human cloning.
“People didn’t know it would be this easy,” James Thomson, head of the research team at the University of Wisconsin-Madison that succeeded in reprogramming skin cells into pluripotent stem cells, told CNN. “Thousands of labs in the United States can do this, basically tomorrow.”
Thomson, who pioneered research using stem cells derived from embryos in the late 1990s, admitted to The New York Times Nov. 22 that he had always had ethical qualms about that procedure.
Said Thomson, “If human embryonic stem-cell research does not make you at least a little bit uncomfortable, you have not thought about it enough.”
Another scientific disadvantage of stem-cell research based on cloning is that the creation of clones requires a supply of human eggs obtained from women of child-bearing age. The procedures required to obtain eggs are painful and carry risks of infertility, injury and even death to the women who donate them. Consequently, few women are willing to become donors.
In the U.S., research using the new procedure has an additional advantage — it qualifies for federal funding, said Princeton professor Robert George, a member of the President’s Council on Bioethics.
An Aug. 9, 2001 executive order issued by President Bush prohibits funding of research that involves the killing of human embryos to obtain new lines of human stem cells (the executive order allows funding for research utilizing cell lines that were already in existence).
George said that direct reprogramming was one of three approaches the bioethics council identified in a 2005 white paper as promising potential alternatives to morally flawed cloning-based research. From a moral perspective, in fact, the council regarded it as the best way to obtain pluripotent stem cells but it was also thought to be the farthest from being scientifically possible.
Said George, “But of course we’re very delighted to be wrong, because it’s great that the method that we saw as the ‘gold standard,’ as the best possible outcome, is the one that has now been vindicated.”
According to Maureen Condic, associate professor of neurobiology and anatomy at the University of Utah, the scientific advantages of working with the reprogrammed cells — and the fact that they are not morally problematic — is likely to attract a flood of new researchers into the stem-cell field.
Said Condic, “The fact that this approach is both scientifically fascinating, remarkably simple and unrestricted for federal funding will attract large numbers of new investigators to stem cell research and greatly accelerate the pace of discoveries and the development of new therapies.”
British researcher Ian Wilmut, head of the scientific team that cloned Dolly the Sheep in 1997, has announced he intends to abandon cloning-based research in favor of the new procedure. Direct reprogramming is “100 times more interesting” than cloning, Wilmut told the Daily Telegraph Nov. 16.
Even researchers who continue to promote research using embryonic stem cells derived from human clones, such as Dr. Robert Lanza of Advanced Cell Technology, agreed that direct reprogramming will revolutionize the field.
Pro-cloning researchers argue it will be necessary to continue cloning-based research, partly to make sure that direct reprogramming is capable of delivering the same results. They also point out that the viral material used in reprogramming the cells has the potential to cause cancer, meaning that reprogrammed cells created in this manner can’t be used for therapies in patients.
Grompe agreed that research using stem cells from embryos should continue until it has been scientifically established that reprogrammed cells can do everything that cells obtained from embryos can. But Grompe said the pre-2001 stem-cell lines approved under the terms of Bush’s executive order are sufficient for that purpose, meaning there is no reason to continue with clone-and-kill research initiatives.
As for the cancer-causing potential of cells created through direct reprogramming, Condic said researchers already are familiar with techniques that can overcome such problems. She said, “These concerns can almost certainly be addressed using currently available scientific technologies.”
Tom McFeely is based in
Victoria, British Columbia.