The Bush administration has defended itself against critics who say its month-old human embryo stem cell policy is too restrictive. It says the few dozen stem cell colonies eligible for U.S. funding under the policy are more than adequate to advance research. But the administration's top health official admits less than half the cell lines are ready to research.
President Bush limited U.S. funding for human stem cell research to those cells collected from embryos before August ninth, the date he issued the policy. His stand allows scientists for the first time to apply for government money for stem cell research while removing the incentive to kill more embryos.
Stem cells are immature cells that can develop into any type of human tissue. Scientists say they hold promise as therapies to rejuvenate tissue to replace damaged or diseased organs.
U.S. officials have identified 64 eligible stem cell lines in 10 U.S., Israeli, Indian, Swedish, and Australian labs.
U.S. Health Secretary Tommy Thompson told the Senate Health Committee Wednesday that they are sufficient to meet researchers' needs because stem cells copy themselves endlessly.
He admits that only about 25 of the cell colonies are ready for use, while the rest are in various stages of development. Yet Mr. Thompson says those probably will be available by the time government research money is available. "We believe the stem cell derivations that we've identified are adequate and ample for basic research, even though some are at various stages of development," he said. "First, we will not be taking applications for funding until after October first. It will probably take eight to nine months to get the dollars out, and during that eight to nine months, a lot of those lines will have been fully developed, making those available."
Many lawmakers believe the president's stem cell funding policy is too restrictive. The hearing was the first opportunity for the administration to defend its policy after the summer legislative recess.
But Harvard University stem cell researcher Douglas Melton took issue with it. He disputed Mr. Thompson's claim that 64 endlessly replicating human stem cell colonies are enough. He says they lose potency over the generations. "It is true that these lines can grow forever and are in that sense immortal," he said. "But they lose their potential. A 150 year-old person may still be alive, but does not have the same potential as a 20 year-old."
Several members of Congress have said they will promote legislation to lift the Bush stem cell research funding restrictions. Among them is Senator Arlen Specter, a member of the president's own Republican Party. He testified to the Senate committee that he has doubts about the strength of the 64 cell lines. "The president has made an important opening of the door, but there is a real question as to whether the door is opened sufficiently," said Senator Specter. "And it has become apparent that many of the stem cell lines cited are not really viable or robust or usable."
Health Secretary Thompson, meanwhile, announced the first agreement making stem cells from authorized sources available to scientists. The U.S. government's National Institutes of Health has obtained the right for its researchers to use cells from the Wisconsin company WiCell and to publish the results. Mr. Thompson says the agreement lets the government make the cells available to other scientists. He says he hopes it is a model for negotiations with other groups owning stem cell lines.