Stem Cells: The Hope And The Hype

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The presidential lines, scientists say, are wasting money as well as time. Larry Goldstein's lab at the University of California at San Diego is a life-size game of connect the dots. Each machine, cell dish, chemical and pretty much every major tool bears a colored dot, signaling to lab workers whether they can use the item for experiments that the government won't pay for. Goldstein's team is working on a cancer experiment that relies on a $200,000 piece of equipment. They can use either an approved cell line that will yield a less reliable result or a freshly created line that would require the purchase of another machine with private funds. "It's a ball and chain," Goldstein says. "It's goofy. Imagine if your kitchen was a mixture like that, where you can't use those pots with that soup."

Congress tried to address the problem with its bill to allow funding for research on any leftover embryos donated by infertility patients. But even if Bush hadn't vetoed the bill, it wouldn't have solved the supply problems. One study estimated that at best, a couple hundred cell lines might be derived from leftover IVF embryos, which tend to be weaker than those implanted in patients. The very fact that they come from infertile couples may mean they are not typical, and the process of freezing and thawing is hard on delicate cells.

SOLVING A PROBLEM CREATED NEW ONES

In the wake of Bush's original order, Harvard decided to use private funding to develop about 100 new cell lines from fertility-clinic embryos, which it shares with researchers around the world. Scientists, desperate for variety, snap them up. "Not all embryonic-stem-cell lines are created equal," says Dr. Arnold Kriegstein, who runs the Institute for Regeneration Medicine at the University of California, San Francisco. "Some are more readily driven down a certain lineage, such as heart cells, while others more easily become nerve. We don't understand how it happens, but it does mean we need diversity."

At the same time, Harvard has opened another battleground in the search for cells. After exhaustive ethical review, its researchers announced this summer that they would develop new cell lines through somatic cell nuclear transfer, or therapeutic cloning. In this process, a cell from a patient with diabetes, for instance, is inserted into an unfertilized egg whose nucleus has been removed; then it is prodded into growing in a petri dish for a few days until its stem cells can be harvested. Unlike fertility-clinic embryos, these cells would match the patient's DNA, so the body would be less likely to reject a transplant derived from them. Even more exciting for researchers, however, is that this technique can yield embryos that serve as the perfect disease in a dish, revealing how a disease unfolds from the very first hours.

The long-term promise is boundless, but the immediate barriers are high. The only people who claim to have succeeded in creating human-stem-cell lines through nuclear transfer were the South Korean researchers who turned out to be frauds. It will take much trial and error to master the process, but where do you get the human eggs needed for each attempt, particularly since researchers find it ethically inappropriate to reimburse donors for anything but expenses? And even if the technique for cloning embryos could be perfected, would Congress allow it to go on?