To scientists who had, for weeks, hoped against hope that President George W. Bush would allow federal money to support research on embryonic stem cells, the only good thing about his decision was that it wasn't worse. Bush announced that he would permit government funding--in practical terms, grants by the National Institutes of Health (NIH) to scientists at universities and hospitals--for experiments only on existing stem-cell lines. "Bush exceeded the very low expectations scientists had for him," says Dr. Joseph J. Fins of New York's Weill Cornell Medical Center. "It's certainly better than an outright embargo." But not by much, concluded many stem-cell biologists. Restricting NIH support to experiments on cells that are already growing in labs "is going to delay substantially the progress we have to bring [stem-cell] therapies to the bedside," says stem-cell pioneer John Gearhart of Johns Hopkins University. By so limiting the research, agrees Dr. Michael Soules, president of the American Society for Reproductive Medicine, Bush "will severely inhibit our ability to unlock the huge potential of embryonic stem cells."
Although that might sound like grousing from scientists who resent brakes on controversial research, there were sound reasons for concern over Bush's decision. Stem cells, as the nation's recent crash course in biology has taught, come from days-old embryos the size of the dot over this i. At this stage, the embryo, created in a fertility clinic, is a hollow sphere; the inner cells are the now-famous stem cells. They have the potential to develop and differentiate into any of the 200-plus kinds of cells in the human body, from heart to bone, and are thus called pluripotent. Every time scientists isolate stem cells, and grow them in a nutrient medium in the lab, they create a "cell line." Biologist James Thomson of the University of Wisconsin created the first such colony in 1998. Today, the NIH determined, 60 stem-cell lines exist in the world: in the United States, Israel, Australia, Sweden, India and Singapore.
Stem cells' talent for propagating would make a dandelion jealous. Since they are endlessly self-renewing, producing countless identical progeny, 60 lines should produce as many stem cells as scientists could possibly need. But "should" is not "will." Stem cells sometimes get, well, stale. "We don't know if the cells have been transformed in any way so that they've become biologically different from those of the days-old embryo," says Cornell's Fins. If so, they may have lost their pluripotency, the trait that makes stem cells so valuable in the first place. And stem cells can "crash." Of the six colonies created by the biotech firm Geron Corp., four are too unstable to be of any use. To think that the promise of stem cells--treating Parkinson's disease and Alzheimer's, spinal-cord injury, diabetes, multiple sclerosis, heart disease and so many other killers--can be realized through research only on existing cell lines, says Evan Snyder of Harvard University, "is scientifically naive."
Even if the 60 stem-cell lines hold up biologically, there might be other barriers to getting the most out of them. The University of Wisconsin holds the patent on isolating pluripotent stem cells from embryos; Thomson's nonprofit WiCell Research Institute has distributed his cells to 30 institutions and has a backlog of 70 requests. Researchers worry that there might not be enough stem cells to support the hundreds, and possibly thousands, of research teams ready to investigate stem cells. "The more smart people you have working on a problem, the sooner you're going to have solutions," says Snyder. Instead, "science has been rationed." Another concern is that many--the NIH refuses to say how many--of the 60 lines are in private hands. "We have had a lot of discussions with these companies," says NIH's Lana Skirboll, who oversaw the NIH's recent stem-cell report. "They very much are willing to work with us to make sure our researchers get access to these cell lines." But companies aren't known for sharing their valuable cells with no strings attached. If you license cells from a private company, "you aren't allowed to use them for this or that purpose, or you have to give up the rights to any discoveries you make," says biologist Robert Lanza of the Massachusetts biotech firm Advanced Cell Technology.
In his speech, Bush raised the specter of cloning humans for replacement organs. Many scientists think that public confusion over cloning--and the belief that stem-cell research makes it easier--influenced Bush's decision to restrict stem-cell work. "Researchers are telling us the next step could be to clone human beings to create individual designer stem cells, essentially to grow another you to be available in case you need another heart or lung or liver," the president said. The first part of that is almost right. At a meeting at the National Academy of Sciences last week, two outside-the-mainstream infertility doctors, plus a chemist who has expressed the belief that aliens created humans, said they intended to clone people. By that, they meant they would take a cell from an adult, inject its DNA into a human ovum, impregnate a woman with that ovum and deliver a baby nine months later. Virtually every scientist dismisses that as both abhorrent and nearly impossible--and the idea of using that individual as a source of replacement organs as doubly so. But the middle part of Bush's sentence--creating "individual designer stem cells"--is real, if not nearly so scary. All it means is taking DNA from a patient, and substituting it for the DNA in stem cells. Then, when the stem cells morphed into specialized cells, such as neurons, they would be a perfect genetic match for the patient. But the end result of "designer stem cells" is a dish full of cells, not a person.
The NIH will now begin accepting grant applications for embryonic-stem-cell research. Only studies using one of the 60 cell lines will be considered; any lines created after the NIH made its count are off limits. The NIH expects to start awarding grants in early 2002. Soon thereafter, as scientists explore the power and the limitations of these lines, it should become clear if Bush's decision is a Solomonic compromise, or a cruel blow to millions of patients for whom embryonic stem cells might offer the last chance for health and life.