Ethical Breakthrough Seen as Scientists Report Stem Cells Without Embryos

By Patrick Goodenough | July 7, 2008 | 8:06 PM EDT

( - The White House Tuesday welcomed news of a breakthrough in stem cell research that some ethicists believe could spell the death knell for the controversial science of cloning human embryos for their cells.

Two scientific journals published results of separate work by researchers at the University of Kyoto in Japan and at the University of Wisconsin in Madison who report that they have turned human "adult" skin cells into cells that behave like embryonic stem cells (ESCs).

The work builds on earlier accomplishments by the Japanese scientists who obtained ESC-like cells by inserting four genes into skin cells taken from mice, but now has been achieved with cells from a human patient, taken in a simple skin biopsy. It raises the prospect of a steady supply of cells that act like ESCs, but do not come from an embryo.

Stem cell research has become one of the most contentious issues in modern science, because many proponents argue that cells sourced from human embryos hold the potential for future treatments for diseases and injuries. But in the process of harvesting the ESCs, the embryos - whether cloned in a lab or unwanted "spares" from IVF treatment - are destroyed.

Parallel research uses adult stem cells from non-controversial sources like bone marrow and placentas, and which have - unlike in the case of ESCs - already reportedly yielded dozens of treatments.

President Bush, who supports adult stem cell research, has on pro-life grounds twice vetoed legislation that aims to expand federal funding for ESC research.

On Tuesday the White House said in a statement the president was "very pleased" to hear about the newly reported advances.

It noted that one of the studies reported was partly funded by the National Institutes of Health, operating under Bush's policy of "encouraging scientific advancement within ethical boundaries."

"The president believes medical problems can be solved without compromising either the high aims of science or the sanctity of human life," the statement said.

The Japanese study, led by professor Shinya Yamanaka of Kyoto University, was published in the journal Cell. Another journal, Science, reported on the work done by researchers led by James Thomson at the University of Wisconsin.

Using what some have dubbed the "Yamanaka method," both teams reprogrammed human adult skin cells to transform into the ESC-like cells known as "induced pluripotent stem" (iPS) cells.

As in the case of ESCs from an embryo cloned from a patient's genetic material, the reprogramming generates stem cells that are genetically identical to the patient from whom the skin cells were taken - but without the ethical problems.

Thomson said there remain concerns about the possibility that a virus used to insert the genes into the skin cells could mutate and cause tumors in tissues grown from the iPS cells, although scientists hope this is a technical limitation that can be eliminated.

Before the latest studies were published, Ian Wilmut, creator of the world's first cloned mammal - Dolly the sheep - and a leading proponent of cloning for stem cells, announced he was abandoning cloning in favor of the "exciting" Yamanaka method.

Dr. David van Gend, national director of Australians for Ethical Stem Cell Research, said Tuesday the two new studies were "magnificent" and reflected "stunning, beautiful science."

He cautioned that the organization was not necessarily conceding that there was a valid need for cells that behave like ESCs, "since all their claimed uses can be done better already with [adult stem cells]."

"These ESC-types may still be a mere freak show, with their uncontrollability in the lab, their tumor propensity - but at least, if scientists must obtain this sort of cell to play with, they can now obtain it ethically," van Gend said.

See Earlier Story:
Cloning Pioneer Changes Direction, May Impact Embryonic Research Debate (Nov. 20, 2007)

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Patrick Goodenough
Patrick Goodenough
Spencer Journalism Fellow