Friday August 24 7:33 PM ET
Bush: 60 Stem Cell Lines 'Ample' Despite FDA Rule
By Todd Zwillich

WASHINGTON (Reuters Health) - President George W. Bush (news - web sites) defended on Friday his decision to limit federal funding for human embryonic stem cell research to 60 existing cell lines amid reports that stringent government regulations could restrict how and where the cells can be used.

Speaking at a news conference near his ranch in Crawford, Texas, the president responded to reports in The Washington Post that most if not all of the cell lines eligible for research under his rules were combined with embryonic mouse cells during the derivation process. That contact between animal cells and cells slated for human implantation invokes strict Food and Drug Administration (news - web sites) (FDA) rules intended to prevent the spread of animal diseases into humans.

The rules limit which patients may receive foreign (''xenotransplanted'') cells and also place strict guidelines on how researchers may use the cells in their investigational work. Mouse cells are typically used in the derivation process as ``feeders'' that aid the growth of human stem cells in the laboratory.

President Bush told reporters that experts from the National Institutes of Health (news - web sites) (NIH) had assured him that the existing stem cell lines ``are ample'' to advance stem cell research, even in light of the FDA safety restrictions.

``This is their opinion, and I can think of no better opinion on which to base my judgment,'' he said. He added that he had ``not changed my opinion in the least'' after learning about FDA restrictions on the cells.

The president announced on August 9 that federal funding for human embryonic stem cell experiments would be limited to about 60 cell lines that had already been derived by that date. The decision was intended to allow research to go forward without spending public money on the further destruction of human embryos.

Since then, the White House has faced continuing questions about the quality of existing lines and also about how private companies who own the lines will be encouraged to share them.

White House officials said that they were aware of the FDA issue when they formulated their decision on embryonic stem cells. They argued that the issue would not be a hurdle to progress in finding disease cures since stem cell research is now at a basic stage and would not require human implantation for years to come.

Still, the president seemed to place on NIH officials' shoulders the responsibility for the ultimate usefulness of the 60 cell lines eligible for federal funding under his decision.

``The NIH came into the Oval Office and they looked me right in the eye and they said, 'We think there is ample stem cell lines to determine whether or not this embryonic stem cell research will work or not,''' Bush said.