News Analysis: The Stem Cell Shuffle
U.S. policy is nearing a tipping point, as controversial research on embryonic stem cells gains allies on both the scientific and political fronts.
The year is not yet half over, but it is looking like 2004 may well be the year of the stem cell. These primitive cells have been at the center of astonishing announcements from labs worldwide. And as U.S. election politics heat up, federal policy on stem cell research teeters in the balance. At issue is President George W. Bush’s 2001 policy, which restricts federal funding of embryonic stem cell research, slowing U.S. contributions to the field.
Since then, stem cells have become an odd sort of political football. “Almost once a month, some scientific article is used to support or oppose a particular political view,” either for expansion of embryonic stem cell research or for a continued focus on adult stem cells, says Robert Goldstein, chief scientific officer of the Juvenile Diabetes Research Foundation. “That’s very unusual for science.”
The latest turnover in the stem cell scrimmage comes from Harvard University cell biologist Douglas Melton. In a paper published May 6 in the journal Nature, Melton and colleagues hunted for evidence of long-hypothesized adult stem cells in the pancreas that might continually replenish beta-cells, the insulin-producing cells that fail in type I diabetes. In a series of elegant and rigorous mouse experiments, they found none.
While so-called adult stem cells found in tissues such as bone marrow and brain can each become several different types of cells, the most flexible stem cells are those derived from three- to five-day old embryos-tiny balls of cells, typically those created in excess during in vitro fertilization treatments and that would otherwise be discarded. In embryos, the stem cells eventually develop into every type of tissue in the body; outside, they offer potential cures to diseases such as ALS (Lou Gehrig’s disease), diabetes, cancer, and Parkinson’s. Bush’s policy allows unrestricted federal grants for adult stem cell research but limits funds for embryonic stem cell research to the 78 “approved” cell lines that existed in August 2001. The guidelines were designed to allow rapid progress in embryonic stem cell research while discouraging further destruction of embryos.
Melton first made news earlier this year when he announced that his lab had developed 17 new embryonic stem cell lines using private funds-lines he would provide to any researcher free of charge, but that, of course, could not be investigated using federal funds. His latest paper prompted headlines proclaiming embryonic stem cells the only possible means of renewing beta-cells and curing type I diabetes. Though this evidence seems to leave adult stem cells out of the running for diabetes therapy, Melton’s experiments actually reveal a non-stem cell possibility: stimulating the few active beta-cells that may remain in diabetic patients to regenerate. “The big conclusion from this,” Melton says, “is that there are only two demonstrable sources to replenish pancreatic beta-cells: one is an embryonic stem cell, and the other is an already existing beta-cell.” Both, he says, need to be pursued.
Still, Melton’s paper does buttress the argument for the unique advantages of embryonic stem cells-in particular, his research shows that adult stem cells simply cannot fulfill a wide variety of purposes the way embryonic stem cells can. “People have used the argument-not a scientific argument but a political argument-that we don’t need to do human embryonic stem cell research because, after all, mature or adult stem cells will do everything,” says Goldstein. “Doug’s paper says that’s not exactly correct.” The upshot, he says, is that scientists need to study both embryonic and adult stem cells.
Melton concurs, saying: “Any scientist would reasonably say, of course work should be supported on both until we know more.”
As the scientific justification for embryonic stem cell research grows firmer, the politics of the issue are starting to turn. For the last few years, former first lady Nancy Reagan has quietly advocated embryonic stem cell research-largely because of the cells’ potential to help Alzheimer’s patients like her husband, former president Ronald Reagan. Earlier this month, she stated this position publicly for the first time. Her speech, given at a Juvenile Diabetes Research Foundation fundraiser, is seen as a public-relations breakthrough for the field. Last fall, a Juvenile Diabetes Research Foundation poll found that 56 percent of self-identified conservatives supported embryonic stem cell research.
Support for the field is growing in Congress, too. In late April, 206 of the 435 members of the House of Representatives signed a letter asking Bush to expand the policy to allow federal funding of research on new stem cell lines. The signers included more than 30 Republicans-among them abortion opponents Randy “Duke” Cunningham and Dana Rohrabacher, both of California. The letter stated that only 19 of the 78 approved lines have turned out to be useful, and even those are often difficult to obtain and often come with restrictive intellectual property agreements. A similar letter is expected from the Senate following the Memorial Day recess; Larry Soler, vice president for government relations at the Juvenile Diabetes Research Foundation, expects about 60 of the 100 senators to sign it-including such prominent Republicans as Arlen Specter of Pennsylvania, Trent Lott of Mississippi, and long-time embryonic stem cell research supporter Orrin Hatch of Utah.
There are even signs that the Bush administration itself might reconsider its position. Look, for example, at the May 15 letter to Congress from Elias A. Zerhouni, director of the National Institutes of Health, sent in response to the House letter to Bush. Zerhouni’s missive reiterated administration policy, but it also acknowledged that, from a scientific perspective, access to more stem cell lines could speed research. “It’s the first time anyone within the administration has said that,” says Soler. “So I think of it as very important.”
The time may have finally come for the United States to put science ahead of politics and fully support research that could benefit hundreds of millions of its citizens.
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