Democrats stage 2nd showdown over stem cells

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He is tracking how batches of embryonic stem cells created by U.S. researchers are being shipped abroad, and worries that other countries more aggressively pursuing the field may be first to turn the master cells into cures unavailable to Americans.

“Will patients have to travel to Australia to get the therapies?” he asks.

Embryonic stem cells are able to morph into any of the more than 220 cell types that make up the human body. They typically are culled from fertility-clinic leftovers otherwise destined to be thrown away. But because the culling kills the embryos, Bush on Aug. 9, 2001, restricted government funding to research using only the embryonic stem cell lines then in existence, groups of stem cells kept alive and propagating in lab dishes.

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The problem: There are only about 21 of those lines available for study, most created in ways that preclude use in humans. At least 300 more lines now are available that many scientists insist are better suited for implantation into sick people.

The new legislation wouldn’t fund the creation of stem cell lines and hence any embryo destruction, but it would allow the National Institutes of Health to fund research using those already existing newer stem cell lines.

The federal stalemate hasn’t halted the work: Scientists are using private money to research newer cell lines, and five states are pouring millions into it. Indeed, when the NIH listed eight top advancements in the field for 2006, five of the projects involved privately funded cell lines.

What about other approaches? Embryonic stem cells mature into adult stem cells that make only a certain type of tissue. Scientists one day hope to turn back the clock, turning, say, blood-producing stem cells found in bone marrow into the type that could grow a liver.

A study in Oregon is transplanting stem cells from aborted fetuses into the brains of children with a killer neurologic disease, to see if they might stop the damage.

Fetuses also shed stem cells into the amniotic fluid cushioning them, allowing scientists to cull those cells harmlessly when pregnant women undergo birth-defect tests. Those cells can turn into several tissue types, but don’t yet seem as flexible as embryonic ones.

And scientists are working on ways to cull stem cells from embryos without killing them.

All this work is years away from fruition, specialists caution — and studying one at the expense of another could mean missing breakthroughs. For example, the pancreas doesn’t seem to harbor adult stem cells, said Dr. Leonard Zon, stem cell chief at Children’s Hospital Boston.

“If you want to try to make cells that produce insulin, you have to use embryonic stem cells,” he said. “New ways of making cells that have embryonic stem cell characteristics are very important to pursue, but they shouldn’t inhibit ... the progress already moving forward.”

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