Beyond Frist's Stem Cell Flip-Flop

The big biomedical research news Friday was Sen. Bill Frist’s change of heart on embryonic stem cell research, which could prompt President Bush to exercise his first veto. But William Saletan, Slate.com’s national correspondent, ran a comprehensive, brilliant five-part series last week showing why this politically motivated flip-flop (Frist wants to run for President in 2008 and polls overwhelming show the public supports medically-motivated embryonic stem cell research) won’t be the last decision he and other politicians will have to make on this issue.

Saletan’s is the first journalist I’ve read who understands the difficulties scientists face in turning embryonic stem cells (or any other type of stem cell) into usable, transplantable tissues. These difficulties have been carefully hidden from public view amid the hype needed to pass state cell initiatives like California's Prop 71.

What are those difficulties? The cookbooks for growing those cells into heart cells (repair damaged hearts), neural cells (Parkinson’s, Huntington’s, spinal cord injuries, etc.), or pancreatic cells (diabetes) are at least a decade away. Moreover, there are signs that cells grown outside their “natural environment,” i.e. in the womb or a Petri dish that contains the whole developing embryo, not just its stem cells; do not properly differentiate into the types of cells that will be needed for these therapeutic interventions.

Saletan concludes that stem cell researchers will soon push to grow embryos longer than the 14-day limit imposed by most ethics rules, perhaps to as long as two months. That way, the cells can begin to differentiate naturally into the cell types of their eventual use. Moreover, he predicts these embryos will inevitably be clones of the patient’s DNA, since most scientists believe this is necessary to get around tissue rejection problems.

Saletan, author of “Bearing Right: How Conservatives Won the Abortion War,” concludes: "The definition of the embryo is blurring. Under a proposal by William Hurlbut, a member of Bush's bioethics council, a single genetic tweak could turn a would-be embryo into a 'clonal artifact, that 'might legitimately be developed within artificial microenvironments beyond 14 days. This would allow the production of more advanced cell types, the study of tissue interactions and the formation of primordial organismal parts.' Why has Hurlbut, a pro-lifer, invited scientists to grow and exploit near-embryos in artificial environments beyond 14 days? Because he knows that the demand for parts and tissues, combined with the difficulty of making them from stem cells, will build pressure to lift the 14-day limit on the real thing."

Dear Dr. Frist: Keep those flip-flops handy.