Stem cell breakthrough uses skin cells rather than embryos

Two teams of scientists simultaneously announced they have reprogrammed human skin cells to obtain pluripotency, the characteristic hailed in embryonic stem cells as having the potential for therapeutic breakthroughs in areas ranging from Parkinson's disease to diabetes.

Scientists in Japan and Wisconsin created the so-called induced pluripotent cells by introducing different combinations of genes into skin cells that are normally switched off after embryonic cells differentiate into various cell types. The results were published last month in Cell and Nature, respectively.

Researchers, ethicists, religious leaders and politicians hailed the findings, saying the innovative work could allow society to reap scientific and medical benefits of stem cell research without destroying embryos.

"If this becomes a way to get pluripotent stem cells, then you've gotten around some significant ethical and logistical problems with stem cell research," said Josephine Johnston, associate for law and bioethics at the Hastings Center, the seminal bioethics think tank. She added that researchers "haven't solved the moral disagreement, but they have avoided the problem."

The White House also applauded the news. In 2001, President Bush issued an executive order that limited federal funding for research to 60 existing embryonic stem cell lines. He has since vetoed two bills to fund research involving embryos generated during in vitro fertilization treatments and headed for the biohazard bin. In a statement, Bush said he "believes medical problems can be solved without compromising either the high aims of science or the sanctity of human life."

The U.S. Conference of Catholic Bishops also hailed the news, as did Nigel M. de S. Cameron, PhD, the president and co-founder of the Institute on Biotechnology & the Human Future, housed at Chicago-Kent College of Law.

"The rhetoric of the last few years was, 'Keep politics out of science, keep ethics out of science. You're slowing things down.' But science is amazingly versatile and can find solutions that are far more elegant and far more subtle than we might have imagined," Dr. Cameron said.

But the scientists responsible for the new stem cell methods said it is too early to set aside research involving human embryos.

The lead scientist for the Japanese team, Shinya Yamanaka, MD, PhD, of Kyoto University, said in a statement that "it is premature to conclude that [induced pluripotent] cells can replace embryonic stem cells." Dr. Yamanaka said he plans to continue working with human embryos to test the pluripotency of reprogrammed skin cells and compare how they develop.

James A. Thomson, PhD, the lead scientist for the Wisconsin team, agreed. "I don't like the idea of pulling the plug" on embryonic stem cell research, he said in a conference call.

Jonathan D. Moreno, PhD, professor of medical ethics at the University of Pennsylvania, was one of many experts to note that the earmarks of embryonic pluripotency could not have been understood or re-created using skin cells without research involving human embryos.

"It's entirely possible we'd have gotten here faster had the whole field not been stigmatized," he said.

Should others replicate the feat of inducing pluripotency in human skin cells, another moral quandary could be averted, Dr. Moreno added. As co-chair of a National Academies' committee, he helped craft guidelines limiting payments to women who donate ova for embryonic stem cell research to compensation for direct expenses. Many researchers said the rules limited their ability to obtain human oocytes, considering that women are paid thousands to donate to fertility clinics. But if embryos are not needed, neither are eggs.

Meanwhile, researchers at the Oregon National Primate Research Center published a paper in Nature online last month showing that they were the first to obtain embryonic stem cells from cloned primate embryos. It took them more than 300 attempts, however. Even if the method proves successful in humans, that is a lot of ova.

"As the work moved forward, it would have required more eggs," Dr. Moreno said. "The pressure on that problem was definitely increasing. ... Maybe I'm off the hook now."