The federal government for the first time will begin funding research on stem cells isolated from human embryos, the National Institutes of Health announced Wednesday.
Stem cells, the precursors of all other cells in the body, show great promise for treating a broad variety of human diseases. But antiabortion groups have vociferously objected to their use because the cells can only be obtained from fetal tissue.
Harold E. Varmus, the head of the NIH, had announced in January that the agency would begin to fund stem cell research. Tuesday's announcement confirmed that decision and set out the safeguards that the agency has designed to prevent such research from being abused.
The cells in question, called pluripotent stem cells, are highly coveted by researchers because they are the mothers of all cells. They have the ability to evolve into any other type of cell, such as bone or muscle. Brain cells derived from them might, for example, be used in treatment of Parkinson's and Huntington's disease and perhaps even Alzheimer's.
Animal studies have shown that the cells can also help repair damaged hearts, spines and other organs. Using the cells as a starting point, it might even be possible eventually to grow whole new replacement organs.
Under the proposed guidelines, researchers who receive federal funds would have to obtain the stem cells from privately funded researchers who extract them from fetal tissues.
The researchers would be forbidden from creating embryos specifically for research.
But they could use stem cells from, for example, "excess" embryos at fertility clinics. Clinics that perform in vitro fertilizations often produce more embryos than are actually implanted in a woman's womb. Stem cells from those embryos could be used but only if the donation is completely voluntary, the guidelines state. Donors must give fully informed consent to the ultimate use of the embryos.
Similarly, stem cells from aborted fetuses could be used if they were donated voluntarily.
Donors may not be offered financial or other inducements, and clinics must have written guidelines to ensure that such inducements are not offered, the guidelines state. Permission can be given only at the stage of fertility treatment when excess embryos would normally be disposed of.
The new guidelines also explicitly forbid attempts to clone humans from the cells or the mixing of human stem cells with animal or human embryos.
The proposed rules also call for the establishment of a Human Pluripotent Stem Cell Review Group to ensure that the rules are followed.
Federal law specifically prohibits funding research on human embryos, but lawyers from NIH have concluded that the stem cells themselves are not embryos, do not have the capability to grow into viable organisms and are thus exempt from the law.
Although the proposed guidelines were not posted on the NIH Web site until late Wednesday, reaction was immediate. The National Right to Life Committee said the guidelines "would result in federal sponsorship and funding of experiments in which living human embryos are dissected and killed. . . ."
Sen. Sam Brownback (R-Kan.) called the research "illegal, immoral and unnecessary." At least 70 members of Congress have previously objected to such research.
Congress could overturn the guidelines by legislation, but there is little prospect of opponents having the votes to do so.
Defenders of the research argue, as Varmus has put it, that "ethical concerns cut both ways, and ethically we have to be concerned with the health of human beings."
The Patents' Coalition for Urgent Research projects that therapies derived from stem cell research could ultimately benefit more than 100 million Americans. The new rules "will prompt the inclusion of the most scientists in the research, thus speeding the day when therapeutic applications are available," said the coalition's chairman, Daniel Perry.
The urgent need to decide whether federal funding would be allowed arose last year when two groups of researchers announced that they had been able to grow large quantities of stem cells in the laboratory. The breakthrough made it possible to produce large quantities of the cells for researchers, opening up new possibilities for scientific study.
The proposed guidelines are posted on the NIH Web site at http://www.nih.gov/news/stemcell/draftguidelines.htm. They will also be published in the Federal Register today. The public has 60 days to comment on them before they become effective.
Times wire services contributed to this story.