Senators Grill NIH Director Over Bush`s Restrictions on Stem-Cel

Two U.S. senators who have staunchly supported biomedical research lambasted officials from the National Institutes of Health on Thursday, saying that the Bush administration's restrictions on embryonic-stem-cell research may be slowing progress in a highly promising field of medicine.

Sens. Arlen Specter and Tom Harkin suggested that NIH officials were improperly playing down the importance of recent discoveries indicating that some types of embryonic stem cells, which the administration has barred researchers from studying using federal funds, may prove especially useful in treating patients.

Mr. Specter is a Pennsylvania Republican who is chairman of an appropriations subcommittee that oversees the NIH's budget, and Mr. Harkin, of Iowa, is the panel's ranking Democrat. The two men were key players in the five-year drive to double the NIH's budget that culminated this year. But during a hearing on Thursday, their tone was at times testy and challenging, with Mr. Harkin voicing "extreme frustration" about the NIH's responses.

Elias A. Zerhouni, the NIH's director, and other NIH officials said the significance of the new findings was still unclear. They predicted that federally financed researchers could make significant progress using varieties of embryonic stem cells approved by President Bush to receive federal funds. Moments later, however, he was contradicted by two university scientists, who said the majority of academic scientists disagreed with that view.

The debate concerns President Bush's decision in August 2001 to allow federal financing only for embryonic stem cells that already existed at that time (The Chronicle, August 17, 2001). Mr. Bush said the policy was justified because of ethical concerns over the use of such cells, which scientists obtained by destroying embryos left over from in-vitro fertilization procedures. Some people regard the embryos as living humans. But many scientists disagree with that view, and believe they can learn how to coax the undifferentiated stem cells to develop into any tissue in the body to treat a variety of diseases such as heart failure and Alzheimer's.

The debate has heated up in recent months because of new findings about how to overcome what could be a key obstacle to the use of embryonic stem cells in humans. The NIH has identified 78 separate colonies, or "lines," of stem cells that can receive federal research funds under Mr. Bush's policy. But most of these were developed by growing the human cells in a culture that contains mouse cells, which for unknown reasons helped the human cells grow.

Scientists and federal regulators are concerned that the resulting human embryonic stem cells may carry dangerous mouse viruses. Another worry is that the genetic material of the human cells may have been damaged by the mixing. Officials at the Food and Drug Administration have asked scientists to do extensive testing of cells before any progeny of the stem cells could be transplanted.

Beginning last fall, researchers in Sweden and Singapore and at the Johns Hopkins University reported separately that they had succeeded in growing new lines of embryonic stem cells without mixing them with mouse cells. However, those new lines are not eligible for NIH research funds because they were developed after Mr. Bush's policy announcement.

Sens. Specter and Harkin pressed Dr. Zerhouni to concede that it would be useful for the president's policy to be loosened to allow researchers to use federal funds to study a greater variety of cell lines, including the non-mouse ones. Universities and corporations own all of the 78 cell lines, but so far only 11 of them have become widely available to researchers.

"It would seem to me we would want to jump on" the latest findings, Mr. Harkin said.

"The hands of scientists should not be tied in any way," Mr. Specter added.

The two senators said they were also dismayed to learn only this week that 16 of the 78 lines approved under the president's policy may have been developed without the use of mouse cells. They are not among the 11 now available to researchers. But Mr. Harkin and Mr. Specter said the NIH had previously assured them that all 78 lines were developed with the help of mouse cells. "It makes me wonder whether the information process has been politicized at the NIH," Mr. Harkin said.

In response, Dr. Zerhouni vowed to be truthful, but otherwise yielded little ground. It will take time for other scientists to independently validate the new reports about the non-mouse cell lines, he said. "We're heard about progress before that did not materialize."

He said that researchers have yet to study the properties of any of the 16 non-mouse lines approved under the president's policy, which are owned by researchers in Sweden. But he said the NIH was interested in supporting further studies of such lines.

Dr. Zerhouni added that scientists can make significant process by studying the biological properties of a limited number of the approved cell lines. That may enable them to draw meaningful conclusions from separate studies of the same cell lines. Those comparisons might not be possible if scientists were studying a multiplicity of cell lines, he said. "We are in every way possible pushing this field," he said.

While he clearly was working hard to support Mr. Bush's policy, Dr. Zerhouni also said that he did not know whether the 78 cell lines will forever and completely meet researchers' needs.

Senator Specter taunted Dr. Zerhouni, pressing him why he had been unable to produce any non-NIH scientist to testify at Thursday's hearing in support of his views.

Dr. Zerhouni's contention that the existing number of lines is adequate was contradicted by Roy Ogle, a professor of neurosurgery and cell biology at the University of Virginia who is studying stem cells. He said that it is important to study multiple lines of embryonic stem cells, because the ones approved under President Bush's policy may have genetic traits that limit their usefulness in developing medical therapies.

Nevertheless, Dr. Zerhouni said that the NIH is moving forward as fast as it can, pointing out that only 5 of the 78 lines approved under the president's policy were available to researchers as recently as last September. It can take a year or more for each line to grow sufficient quantities for distribution, he said. More than 60 scientists at 48 research institutions have received NIH funds to study embryonic stem cells, including $11-million in 2002.

Mr. Specter complained that that was unbalanced compared with the $148-million spent by the NIH in 2002 for studies on stem cells derived from adult human tissue. Such research is not controversial, but many scientists say that the adult stem cells have proven less versatile than those derived from embryos.

"A rate-limiting resource" blocking faster progress with embryonic stem cells has been the lack of scientists with the specialized training needed to work with the delicate cells, said James Battey, who heads the NIH's stem-cell task force. The NIH has been working to change that by holding training seminars around the country.

Toward the end of the hearing, Mr. Specter hinted that he might pursue legislation to overturn Mr. Bush's policy. But some observers believe he would face an uphill battle to persuade his Republican colleagues, who control both chambers in Congress, to go along.

A list of the human embryonic-stem-cell lines that meet the eligibility criteria for federally financed studies is available on the NIH's Web site.