Adult skin cells alter debate over embryonic stem cells
Scientists from Japan and the United States have changed human skin cells into cells that look and behave like embryonic stem cells, a development that could be a turning point in the contentious debate over human embryonic stem-cell research.
“It’s probably the beginning of the end for that controversy,” said James Thompson, a stem-cell scientist at the University of Wisconsin-Madison whose lab was used by the U.S. research team. “I do believe that over time these new cells will be used by more and more labs, and embryonic stem cells will be gradually used by fewer and fewer labs.”
The idea is that these new cells — produced without harming or using any human embryos — eventually could yield the same medical promise as embryonic stem cells.
The news had immediate political impact, as opponents of embryonic stem-cell research said the need for such controversial work is now gone.
“We have no realistic need to destroy embryos,” said Sen. Sam Brownback, Kansas Republican.
Others said that although the news is stunning, embryonic stemcell research should continue.
“It’s a very important scientific discovery. It’s not one that obviates the need for embryonic stemcell research,” said Sean Tipton, president of the Coalition for the Advancement of Medical Research, a group that has led the charge for federal funding of stem-cell research.
The White House, meanwhile, seemed vindicated by the announcement. President Bush has twice vetoed legislation that would have allowed federal funding to flow to even more embryonic stemcell research. Instead, Mr. Bush has encouraged other avenues of research, including adult stem cells and alternative techniques such as the ones used in the studies.
The Thompson team’s research was funded, in part, with federal money from the National Institutes of Health.
A White House spokesman said Mr. Bush is “very pleased” with the discoveries.
“By avoiding techniques that destroy life, while vigorously supporting alternative approaches, President Bush is encouraging scientific advancement within ethical boundaries,” the spokesman said.
Human embryonic stem cells are highly valued because of their ability to develop into essentially any body cell — a trait scientists think eventually could be used to treat a range of diseases. The catch is that human embryos — which are sometimes left over from invitro-fertilization clinics or produced through a cloning technique — must be destroyed in order to extract their stem cells for the research. This has unleashed a storm of controversy from the halls of Congress to the living rooms of America, as people weigh the potential medical promise of stem cells against the value of human embryos.
But the two separate teams — one led by Dr. Shinya Yamanaka of Kyoto University and the other led by Junying Yu in Mr. Thompson’s lab — may have found a way to sidestep that debate. Each team used viruses to inject a recipe of genes into human skin cells and reprogram the cells to act like embryonic stem cells.
The Yamanaka team, whose research is being published in the journal Cell, used four genes to reprogram skin cells taken from a 36-year-old woman and a 69-yearold man. The Yu team, whose research is being published in the journal Science, also used four genes to reprogram cells from fetal skin and from the foreskin of a baby boy. The new cells are called induced pluripotent stem (IPS) cells.
The Yamanaka team in June created mouse cells that were virtually identical to stem cells, but this took the work a step further.
“Our study has opened an avenue to generate patient- and disease-specific pluripotent stem cells,” the Yamanaka team reported. The human IPS cells are useful for understanding disease mechanisms, drug screening and toxicology and “further studies are essential” to determine whether they can replace embryonic stem cells in medical applications, the researchers stated.
The new technique carries with it some problems, including the potential for developing cancer.
Mr. Thompson, who first gained notoriety for coaxing stem cells from human embryos in 1998, agreed more work is needed to ensure safety. And he said it does- n’t mean the end of embryonic stem-cell research. But he said “the world has changed” because of it.
The news evoked praise from scientists, ethicists and lawmakers alike.
“This is extremely significant research because what they’ve done is produce embryonic-type stem cells without any of the ethical baggage,” said David Prentice, senior fellow for life sciences at Family Research Council. “They don’t create or destroy any embryos; they don’t have to do any cloning; they don’t need any eggs.”
Some well-known scientists already have begun to shift toward this new technique.
Dr. Ian Wilmut, the British scientist who cloned Dolly the sheep, recently told the Telegraph that he will abandon the cloning method that produced the animal in favor of Dr. Yamanaka’s method of producing cells.
But others warned that embryonic stem-cell research is still just as important.
“These scientists have performed truly groundbreaking and historic accomplishments. Still, our top researchers recognize that this new development does not mean that we should discontinue studying embryonic stem cells,” said Sen. Tom Harkin, Iowa Democrat and a stem-cell research proponent.
Cloning embryos to produce stem cells is still too powerful a tool to abandon, agreed Rudolf Jaenisch, a stem-cell scientist at the Whitehead Institute.
Mr. Tipton said although the recent discoveries introduce more “competition” into the field, “we need to let scientists tell us what the best source is” — an outcome that only time will tell.
This article is based in part on wire service reports.
Mouse cells that were nearly identical to stem cells were created in June by a research team led by Dr. Shinya Yamanaka of Kyoto University. New research has taken that work a step further.