Tuesday, July 18, 2006

Stem Cells and Ramesh Ponnuru   posted by the @ 7/18/2006 07:20:00 PM

Ramesh Ponnuru has an article in NRO on the embryonic stem cell (ESC) vote. I can't comment on Ponnuru's arguments about Reagan, but I can speak to the science. Ramesh critizes the claims of ESC research advocates. Although these advocates do often stretch the truth on the promise of ESCs, Ramesh's corrections snap back way too far.

264 pro-funding congressmen write, "As you know, embryonic stem cells have the potential to be used to treat and better understand deadly and disabling diseases and conditions that affect more than 100 million Americans, such as cancer, heart disease, diabetes, Parkinson's, Alzheimer's, multiple sclerosis, spinal cord injury, and many others." The claim is worded vaguely enough so that it is not exactly false: You couldn't prove that the research has no "potential" to improve our understanding of the common cold. Under the influence of the pro-funding lobby, relatives of ailing people now believe even stronger claims. Patti Davis's Newsweek article called stem-cell research "the miracle that can cure not only Alzheimer's but many other diseases and afflictions."

But Rick Weiss reported in the Washington Post that, "of all the diseases that may someday be cured by embryonic stem cell treatments, Alzheimer's is among the least likely to benefit." (Embarrassingly for the Post, it ran its editorial arguing that increased funding could lead to Alzheimer's treatments on the same day it ran the Weiss story.) Cancer and heart disease are pretty far down the list, too, although they're useful in generating the figure of "more than 100 million Americans."

These criticisms seem to be based on the belief that the promise of ESCs is as a material source for cell-replacement therapy. Such therapies would ostensibly require the perfection of cloning techniques, a vast resource of human eggs, and large amounts of money. The more likely avenue from ESCs to cures is via the creation of ESC culture systems that model common diseases. From these cell culture models, the molecular basis of each disease could be examined in otherwise unavailable detail... drug targets, blah blah blah.

The president's critics say his numbers have proven wrong: Only 19 subsidized lines are available to researchers. Wittingly or not, the critics are conflating eligibility and availability. The lines that were eligible for funding were not immediately available. Legal rights had to be parceled out, and the lines had to be developed. These processes took time, and not because of Bush's funding restrictions. But the number of available lines has been increasing, and will continue to increase — possibly to as many as 55. The congressmen claim that if Bush's policy were liberalized, research could be done on 400,000 embryos currently frozen at IVF clinics. But the study from which that estimate comes notes that most of those embryos have been stored for future reproductive use. The study indicates that at most 275 additional lines could be generated from these embryos.

Sounds like non-sense, but 275 is 5x more than 55 and 15x more than 19. What's needed are lines that are genomically intact and genetically diverse. Who wants to use the 2001 model when the 2006 model could be made available?

It is certainly true that if the president's goal were to maximize embryonic stem-cell research, to the exclusion of other concerns, he would adopt a more liberal policy. The director of the National Institutes of Health has said as much, in a statement that pro-funding polemicists have treated as a devastating admission. But it is also true that no researcher has complained that the current policy is impeding him; the complaints have been more along the lines that the policy is keeping people from going into the field.

This implies a serious lack of understanding of how biomedical science is done... it's done by grad students, post docs and assistant profs (i.e. new people). Additionally, ESC research is relatively new and relatively small. Keeping it from growing means keeping it from happening.

Funding proponents have sometimes been willing to imply that Bush has prohibited embryo research rather than limited government funding for it. Patti Davis wrote in her Newsweek op-ed that her mother had "emerged as a central figure in the effort to get the federal government out of the way." That is becoming a talking point of the campaign, and it is deeply misleading: The effort is to get the federal government to pay, not get out of the way.

Until such a time when most research is privately funded, this is a serious problem. The prohibition against using government funds means that ESC research (on prohibited lines) cannot commingle with other research. Slight exaggeration: the usual pattern for getting NIH grants is that you have already done most of the work that you propose to do. Then you use that money to fund the work that will be proposed in your next grant. The funding prohibition keeps new research from being started in this fashion.