What a Bush Veto Would Mean for Stem Cells

By NANCY GIBBS, Alice Park, Mike Allen, Massimo Calabresi/ Washington

George W. Bush seldom suffered personally from doing what's unpopular politically. In fact, you could argue that he has made a career of it, holding fast to positions that many voters reject, as a sign of strength in these dangerous times. So his willingness to exercise his first-ever veto this week on a bill that would expand federal funding for human embryonic-stem-cell research, which 2 out of 3 voters favor, is not just a way to stroke his political base. "People like leadership much better than a finger in the wind," says White House press secretary Tony Snow. As Bush explained to him while in St. Petersburg, Russia, for the G-8 summit last week, "I took a position. I believe in it. So that's what I'm going to do."

But most Republicans are not George Bush--among other things, they still need to get re-elected--which is why, as a Northeastern G.O.P. official said, the issue of stem-cell research could be "a stinker" for the party. "When you're portrayed as arguing against treatment of disease," he admits, "it's a tough place to be politically." Democrats, who overwhelmingly support expanded research, seem happy with the looming veto as a consolation prize; some were already running ads. "It's going to be a symbol of standing in the way of progress," says Illinois Congressman Rahm Emanuel, whose job it is to get Democrats re-elected. "This is a game changer in a lot of districts." As for patients, present and future, who have a personal stake in the fight, the good news is that the fate of the bill may not mean as much as either side suggests.

Ever since Bush limited federal funding to a small number of existing stem-cell lines in August 2001, research advocates have been worried that the U.S. would lose its edge in the revolutionary field of regenerative medicine. The "presidential lines" were of limited value; there were not nearly as many as scientists initially thought would be available--more like 21 than 62, and they were old, in some cases damaged and most likely contaminated with the mouse feeder cells and calf serum used to grow them. Top U.S. scientists, many of whom depend on federal grants, decamped to labs in Europe or Singapore, where the government has made biotechnology a national priority. Some states have tried to fill the gap--California voted for a $3 billion bond initiative to fund stem-cell research. Advocates from Nancy Reagan to Michael J. Fox have pushed Congress to unleash more money and loosen the rules. Many Republicans as well as Democrats have been receptive, knowing that even socially conservative suburban voters tend to support the promise of research that they think might cure their parents' Alzheimer's or their children's diabetes. It fell to Senate majority leader Bill Frist, once a Bush ally on stem cells and a heart surgeon himself, to break with the President and build a compromise package with something for everyone to like. One bill increases funding to explore sources of stem cells other than embryos, such as umbilical-cord blood. Another proposal outlaws trade in tissue produced by "fetus farming," pregnancies that are aborted specifically to harvest the tissue for research. ("As far as I am aware," Frist admitted when he announced the bill, "this is not a method currently employed. But it is not out of the realm of possibility.") The part that inspired the promise of Bush's first veto was House Resolution 810, which would allow federal funding for research on any leftover embryos donated by fertility-clinic patients.

Leaving aside election-year sensitivities, supporters point to the moral logic of their position. Leftover embryos are routinely thrown away; surely there is no sin in scientists' deriving potentially lifesaving treatment from them first. Opponents respond that there is nothing to stop scientists from doing that. The issue is federal funding, which Bush believes should focus on research that does not require the destruction of embryos. But aren't those particular leftover embryos already doomed? "We don't take death-row inmates and use their organs either," says David Christensen, the conservative Family Research Council's director of congressional affairs. "We should not kill humans for body parts, at any stage of development."

Feelings run so strong on this issue that opponents have built a practical case to bolster the ethical one. The promise of embryonic stem cells has been oversold, they argue, while actual progress using adult stem cells has been overlooked. Though advocates talk longingly about the 400,000 frozen embryos in fertility clinics, a Rand Corp. study in 2003 found that 86% of them have been designated by patients for their future use or someone else's--there are approximately 100 "snowflake kids," children born from adopted frozen embryos--and only 2.8% for research. Even if that number rose with the release of federal funds, the healthiest embryos are the ones that get implanted, and the act of freezing and thawing embryos may do damage as well. Rand estimated that at best perhaps 275 viable lines would become available. That's 10 times the number now being studied using federal funds, but they would not provide the quality, quantity and genetic diversity that scientists seek.

The good news for all sides is that over the course of this long argument, researchers have learned more about how stem cells work, and the science has outrun the politics. Adult cells, such as those found in bone marrow, were thought to be less valuable than embryonic cells, which are "pluripotent" master cells that can turn into anything from a brain cell to a toenail. But adult cells may be more elastic than scientists thought, and could offer shortcuts to treatment that embryonic cells can't match.

Researchers have discovered that many tissues and organs contain precursor cells that act in many ways like stem cells. The skin, intestines, liver, brain and bone marrow contain these stem cell-- mimicking cells, which could become a reservoir of replacement cells for treating diseases such as leukemias, stroke and some cancers. "Brain stem-cells can make almost all cell types in the brain, and that may be all we need if we want to treat Parkinson's disease or ALS," says Dr. Arnold Kriegstein, who directs the University of California at San Francisco's Institute for Regeneration Medicine. "Embryonic stem cells might not be necessary in those cases." When it comes to treating heart disease, "if you could find a progenitor cell in the adult heart that has the ability to replicate," says Douglas Melton, co-director of the Harvard Stem Cell Institute, "then it's likely easier to start with that cell than begin with an embryonic stem cell, which has too many options."

Cheerleaders for adult stem-cell research point to progress on everything from spinal-cord injuries to diabetes. Scientists at the University of Minnesota have used umbilical-cord-blood stem cells to improve some neurological function; in a paper published last month, Dr. Carlos Lima in Portugal wrote about restoring some motor function and sensation in a few paralyzed patients. At a recent conference of researchers from around the world, a team from Kyoto University in Japan reported success in taking a skin cell, exposing it to four key growth factors and turning it into an embryo-like entity that produced stem cells--all without using an egg. The Kyoto group has submitted its work for publication, after which it will be open to the scrutiny of the scientific community. If successful, it could turn stem-cell science from a tedious, finicky process into a relatively straightforward chemistry project.

All this progress, however, does not yet mean that the demand for embryonic cells will disappear. Most adult organs just don't have enough stem cells to deploy as treatment, and adult stem cells are even harder to grow than embryonic ones. One goal of research is to help scientists understand how embryonic cells duplicate themselves perpetually. When it divides, a stem cell will occasionally create two different daughter cells, one that will continue to develop like any other cell and another that retains the ability to continue dividing indefinitely, thereby giving the cell line its immortality. "Unlocking the secrets of self-renewal will most likely involve studying embryonic stem cells," Kriegstein says. "And by understanding better how they work, we might be able to use that information to actually engineer adult stem cells to do the same thing." Then the discussion over how to handle an embryo could move into another phase, and maybe even leave the politics behind.

For continuing coverage of the President's stem-cell decision, go to time.com