Stem cell alternatives gain key support
WASHINGTON -- Dr. Leon R. Kass, the chairman of the President's Council on
Both proposals, presented yesterday at the first meeting of the council since the presidential election, suggest ways biologists might be able to generate the scientifically promising cells without triggering the objections that have made the research a target of the anti-abortion movement and have prompted President Bush to restrict federal funding for the work.
The proposals still face a range of ethical and scientific hurdles, and neither has yet been attempted, but they received a positive reception from the council, which has generally taken a cautious approach to new biological research. Kass, a conservative philosopher appointed by Bush to head the council, said that after studying the ideas closely, he believes they hold promise for ending the divisive political battle.
''I think these are two extremely interesting, very creative proposals," Kass said yesterday.
The council did not vote on the ideas and has no power over federal policy, but it is a high-profile public venue for addressing controversies over cloning, life extension, and other frontiers of biological research. Kass's endorsement would probably give the ideas a boost in a highly politicized environment.
Though embryonic stem cells are considered scientifically promising for their power to transform into any type of cell in the body, their use has attracted deep opposition because obtaining them requires destroying a human embryo while it is a ball of about 200 cells. Because of this, on Aug. 9, 2001, Bush declared that the federal government will not fund research involving human embryonic stem cells created after that date, saying he did not want the government to pay for the destruction of more human embryos.
''We would take seriously any proposal that would permit stem cell research without violating this important principle," said a White House official yesterday. The official, who asked not to be identified, said the Bush administration would follow the proposals.
The two ideas considered by the council represent different ways to obtain embryonic stem cells without destroying an embryo. One, crafted by council member Dr. William Hurlbut, a conservative bioethicist at Stanford University, would engineer a human egg so that it creates cells equivalent to human embryonic stem cells but never develops into an actual embryo.
The other idea, presented by two Columbia University professors, proposes devising standards for declaring an embryo ''dead." If it is ethically acceptable to allow organ donation from patients who have been declared brain dead, they reason, then it should be acceptable to remove cells from an embryo that has been declared dead.
The Columbia idea was published last month in the Journal of Clinical Investigation. The Hurlbut proposal was reported in the Globe last month and is beginning to trigger heated debate in the political sphere. That debate has revealed politically surprising divides among conservatives: On Thursday, the Family Research Council issued a statement condemning Hurlbut's idea, despite the fact that Hurlbut shares their conviction that destroying human embryos is tantamount to murder. A spokesperson for Senator Sam Brownback, Republican of Kansas and a powerful political force in the opposition to research using human embryos, said he saw little promise in the proposal.
But Representative Dave Weldon, Republican of Florida and another important foe of embryo research, struck a more moderate tone. In a statement sent the Globe, Weldon said the proposal ''is an interesting theoretical proposal" and merits more study.
Weldon and council members, however, cautioned that Hurlbut had not yet demonstrated it is even possible to create something that would generate the equivalent of embryonic stem cells without being considered an embryo.
In the discussion at the council yesterday, some members also raised ethical objections to Hurlbut's idea. The proposal depends on cloning technology, which currently requires hundreds of donated human eggs to produce a single embryonic stem cell; such donations can pose some risk to the women donors. There are also concerns about genetically engineering human egg cells -- so called ''germ line engineering" -- because it involves modifying the human genome.
The other idea was presented yesterday by Dr. Donald W. Landry and Dr. Howard A. Zucker, who are not council members. It relies on the fact that some embryos created for fertility treatment simply ''arrest," or stop dividing. These embryos are typically discarded -- but the Columbia scientists say that some of their individual cells may remain viable.
The scientists argue that biologists could examine very early embryos that have failed to divide for two full days. Perhaps, they suggest, biologists can find clear chemical differences between these embryos and healthy embryos and this chemical signature could be used to determine that the embryo is dead. If it contains viable cells, then the cells could be extracted without harming a live embryo.
There are scientific obstacles to this idea. No one knows whether a ''dead" embryo would contain viable cells that could yield stem cells. Any such cells would be harvested when the embryo had not yet reached the point at which stem cells are normally derived.
Douglas Powers, scientific director of the fertility clinic Boston IVF, also said in a phone interview that it might be difficult to find a biochemical test that could convincingly determine if an embryo is dead.
''It is an interesting proposal, and I really commend them for advancing the debate," said Powers. ''But I suspect it is not practical."
For both proposals, though, there are experiments that scientists could begin now in animals to determine how practical the approaches are. Kass cautioned that his support of the ideas depends on the results of this initial research and said he hoped scientists would pursue the ideas.
Dr. Evan Snyder, a professor and director of the stem-cell and regeneration program at the Burnham Institute in La Jolla, Calif., has said that he is interested in doing experiments suggested by Hurlbut's proposal. But Michael S. Gazzaniga, a Dartmouth College neuroscientist who serves on the council and supports current methods of deriving human embryonic stem cells, said at the council meeting that he fears resources poured into these lines of work could draw resources away from important work that can be done now -- a sentiment echoed by a number of other biologists.
And one prominent foe of embryo research said the proposals could cloud the debate, distracting the public from the fundamental moral questions of tampering with early human gestation.
''There are political considerations," said David Prentice, a senior fellow at the Family Research Council. ''Do we even want to get into this discussion?"
Gareth Cook can be reached at cook@globe.com.
