ST. LOUIS — In the wake of last year's scandal over faked cloning experiments in South Korea, stem cell researchers are getting over their deep disappointment and moving ahead with discoveries — while ethicists are gearing up for a new wave of social and political debate.
Scientists on both sides of that debate said Friday that it's likely just a matter of time before someone really does produce stem cells from cloned human embryos, thus actually accomplishing what South Korean researcher Woo-suk Hwang falsely claimed two years ago.
"Probably over the next couple of years, this will be done," said Leonard Zon, a stem cell researcher at Children's Hospital in Boston. "I think the individual steps are solvable."
The past, present and future of stem cell research was the focus of a St. Louis news briefing on Friday at the annual meeting of the American Association for the Advancement of Science — the very same forum where Hwang made such a splash in 2004.
The annual AAAS meeting brings together hundreds of scientists, students and journalists to review the past year's research in virtually every field, and look ahead to future frontiers. Amid international fanfare, Hwang and his team reported at the 2004 meeting that they had created a human embryo through cloning and extracted viable stem cells from it.
Last year, Hwang went even further, reporting that his process was able to produce 11 new lines of patient-specific embryonic stem cells. Both of Hwang's papers appeared in the journal Science, which is published by the AAAS.
Such an advance seemed to revolutionize the search for regenerative therapies, because embryonic stem cells are capable of transforming themselves into virtually any tissue in the body. Theoretically, harnessing stem cell therapy in that way could lead to the regeneration of injured spinal cords, new heart cells for cardiac patients or new brain cells for Parkinson's disease sufferers.
But other researchers were never able to duplicate Hwang's results. Last fall, his claims crumbled under the weight of fraud allegations. Hwang became the focus of academic and even criminal investigations, and the journal Science retracted Hwang's research.
Some of the speakers at Friday's forum still felt stung by the affair — not only because they were misled, but because it turned out that Hwang's female subordinates were pressured to donate their own eggs. Northwestern University bioethicist Laurie Zoloth said anyone who played even an inadvertent role in Hwang's deception, including herself as well as the research community and even science journalists, should join in a mass apology.
Donald Kennedy, Science's editor-in-chief, was sympathetic: "This is really a twin tragedy —both for the people who were misled over there [in South Korea] and for the people who were misled here. ... I'll certainly join in any ritual apology."
Science launched two investigations of the practices that led to the publication of the fraudulent papers. Kennedy told MSNBC.com that both probes — one by five of the journal's editors, the other by an independent panel — should be ready for review by the AAAS board in mid- to late April. (AAAS is a content provider for MSNBC.com.)
Kennedy said he is often asked whether he could see anything in retrospect that Science could have done to detect the fraud before publication. "I cannot, but my colleagues may," he said.
Staying the course
The researchers at Friday's panel expressed disappointment that Hwang's achievements turned out to be illusory. The Burnham Institute's Evan Snyder said that the creation of genetically tailored human embryonic stem cells through therapeutic cloning, also known as somatic-cell nuclear transfer, would have made it easier to figure out how the cells do their magic in the first place.
"Most of us really regarded nuclear transfer as a technical hurdle, [but] that never was really the goal," he said.
Researchers are continuing to conduct animal studies that hint at the promise of stem cells — both adult and embryonic — for treating human maladies. Several examples were cited Friday:
- Snyder is studying how neural stem cells can migrate long distances through a mouse's body to "rescue" degenerating cells in the brain. The stem cells may produce factors that help revive surrounding cells, which means it may not be necessary to fully replace the degenerating area with new cells. "There actually is an enormous amount of 'crosstalk' that we can take advantage of," he said.
- Zon is working with zebrafish to explore whether hematopoietic stem cells, which are responsible for creating the body's blood cells, can be engineered and then injected to give a boost to ailing immune systems. He reported some success with the technique, and said his group has found "a new pathway that tells the address where blood stem cells are supposed to be."
- At the Johns Hopkins School of Medicine, John Gearhart is also using zebrafish as a model to study how stem cells transform themselves into different tissues in the body. "The efficiency with which you can do this is generally pretty low," he observed. Gearhart's team is looking for the chemical factors that promote the creation of particular kinds of tissues.
- Lawrence Goldstein of the University of California at San Diego said he is concentrating on how to use human embryonic stem cells from genetic lines that have been linked to Alzheimer's disease or Lou Gehrig's disease. Such cells could be tested or even genetically engineered to study the mechanisms behind those diseases — and perhaps identify potential therapies. Referring to Alzheimer's, Goldstein said, "We know a lot about what happens in this disease, but we don't know why."
Meanwhile, the U.S. political debate over stem cell research could heat up again in the coming months. "I think it's going to get worse," said Stanford University bioethicist William Hurlbut, who is a member of the Bush administration's bioethics panel.
The debate could be revived in the next few weeks if the U.S. Senate takes up a House-approved bill that would ease the limits on federal funding for embryonic stem cell research. Although Hurlbut said he couldn't predict what the Senate would do with certainty, he told MSNBC.com that the issue may come up in late March or early April.
Even though Hurlbut is opposed to stem cell research that involves cloning human embryos, he acknowledged that such research would likely continue. "My sense is that people realize this research is going to go forward somewhere in the world," he told reporters.
He said he was not in favor of widening the scope of human embryonic research in the United States because it would "leave our country still divided" along the lines of red states vs. blue states. As an alternative, Hurlbut advocated the development of genetically engineered "constructs" that can produce stem cells but are biologically incapable of embryonic development.
He voiced support for legislation proposed by Sen. Jim Talent, R-Mo., which would set aside $70 million for such research, known as altered nuclear transfer. That money would include a $20 million prize for the first team to harvest stem cells as capable as the embryonic variety without using a human embryo.
Northwestern's Zoloth was critical of the legislation, saying that she couldn't think of a better way "to waste $70 million." She also said polls showed that most people favored doing stem cell research with human embryos — a claim that Hurlbut disputed.
Zon, who is the past president of the International Society for Stem Cell Research, said scientists should investigate all the avenues for new regenerative therapies, including embryonic and adult stem cells as well as theoretical alternatives such as altered nuclear transfer.
"What you don't want to have happen is to have someone say, 'You should stop your research now,' while trying to figure out whether a theoretical approach will work," he told MSNBC.com.
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