Copyright 2003 by the American Association for the Advancement of Science. All rights reserved.
June 30, 2003
As cloning legislation has come to a grinding halt in the Senate, new research results have prompted moderate Republicans in each chamber to focus attention on the issue of federal funding for human embryonic stem cell research.
In March, Johns Hopkins University researchers announced the discovery of a promising new way of growing stem cell lines. Until now, stem cells have been produced with the use of mouse cells as "feeder cells" to keep the stem cells from differentiating into more specialized tissue. However, cells that come into contact with mouse cells can be contaminated with animal viruses, presenting a danger to potential patients. The new technique uses human bone marrow cells instead of mouse cells, eliminating a potential obstacle from scientists' long-term goal of using stem cell transplants to treat conditions such as diabetes and Parkinson's disease.
President Bush's stem cell research policy, announced in a nationally televised address on August 9, 2001, allows federally funded stem cell researchers to work only on cell lines already created at the time of the policy announcement, making research on lines created with the new method ineligible for federal funding.
Initially, the administration compiled a list of 78 eligible cell lines, but to date only eleven of these lines have actually been made available to researchers. Thus, many scientists had been pressing President Bush to revisit the policy even before the Johns Hopkins discovery.
In response to the concerns of stem cell researchers, eleven moderate House Republicans sent a letter to President Bush on May 15 urging him to review his stem cell policy to determine: (1) if enough lines have been made available "for this fast-growing research community;" and (2) "whether changes should be made to allow for the creation of new sterile, uncontaminated stem cell lines" such as those produced at Johns Hopkins.
"U.S. scientists continue to express their concern about the quality, longevity, availability and terms of use of the stem cell lines made available under the policy," the group wrote. "Specifically, the creation of enough sterile, virus-free lines for potential cell-based therapy is of major concern. … We must have a national policy that allows such research discoveries to move forward and not handcuff our scientists."
The letter's eleven signatories included Rep. Michael N. Castle (R-DE), a leader of the Tuesday Group, an informal coalition of Republican moderates; Rep. Sherwood Boehlert (R-NY), chairman of the House Science Committee; and Rep. Jim Greenwood (R-PA), who led opposition to the comprehensive cloning ban that passed the House in February and argued instead for a narrower alternative that would have allowed cloning for research purposes.
In the Senate, meanwhile, Sen. Arlen Specter (R-PA), the chairman of the Labor-HHS Appropriations Subcommittee, held a May 22 hearing on the issue at which he sharply questioned National Institutes of Health (NIH) Director Elias Zerhouni. Dr. Zerhouni defended the Bush Administration's policy and insisted that scientists are moving as fast as possible. There is no current need for new cell lines, he said, although such a need may arise in the future. In fact, Dr. James Battey, the chair of the NIH Stem Cell Task Force, testified that currently the limiting factor in the progress of stem cell research is a lack of scientists trained in the techniques needed to work on stem cells. Sen. Specter criticized Dr. Zerhouni for failing to find a non-government scientist willing to back the administration's position.
Specter also renewed long-standing complaints about communication problems
with NIH after Zerhouni informed the subcommittee that 16 of the 78 cell lines
eligible for federal funding have not been exposed to mouse cells. Specter contended
that Health and Human Services Secretary Tommy Thompson had previously informed
him that all of the eligible lines had been exposed to mouse cells, and he sharply
rebuked Zerhouni for this "flat-out contradiction." In the past, Thompson
has faced criticism from Specter for allegedly allowing his staff to edit communications
from NIH scientists to Specter's subcommittee. The 16 uncontaminated lines are
not among the eleven cell lines currently
available.
Sen. Tom Harkin (D-IA), the subcommittee's ranking member, asked about unpublished reports of 4-5 cell lines that Swedish researchers have derived without the use of mouse feeder cells, and suggested that a change in the administration's policy might be necessary in order to allow NIH-funded researchers to compare these lines to the eleven available lines.
Another witness, Dr. John Kessler of Northwestern University Medical School, confronted Zerhouni's statements head on. He argued that scientists should work on different techniques for developing stem cells "in parallel," but that the administration was forcing scientists to proceed "serially." Both the technique used to derive stem cells and their genetic makeup can alter the cells' properties in important ways, he said, creating a need for the derivation of new lines.
The administration's stem cell policy applies only to federally-funded research, so whether or not President Bush agrees to revisit the issue, privately funded researchers, such as those that produced the recent discoveries as Johns Hopkins, may continue to study new cell lines. As these researchers and scientists abroad report new discoveries, policymakers will face the continuing challenge of ensuring that U.S. policy stays up-to-date. ••• [an error occurred while processing this directive]
Copyright 2003 by the American Association for the Advancement of Science. All rights reserved. |