NAS Report Likely Will Stir Debate

If research involving human embryonic stem cells (ESCs) is to achieve its potential for creating breakthrough medical therapies, additional new cell lines should be created, and therapeutic cloning--or somatic cell nuclear transfer (SCNT)--should be employed, according to an expert panel of the National Academy of Sciences. Both of these views are strongly opposed by the Bush administration, and the US House of Representatives has voted to outlaw human SCNT techniques by public and private researchers. The NAS recommendations are likely to further fuel public policy debates over the future of human ESC research. "Given the promise of stem cell research for treating and perhaps curing a variety of debilitating diseases, our committee felt strongly that research not be limited, but include work on both human adult and embryonic stem cells," stated committee chair Bert Vogelstein, professor of oncology and pathology at the Johns Hopkins University School of Medicine, in releasing the report. "We also believe that new embryonic stem cell lines will need to be developed in the long run to replace existing lines that become compromised by age, and to address concerns about culture with animal cells and serum that could result in health risks for humans." The NAS Committee on the Biological and Biomedical Applications of Stem Cell Research was assembled earlier this year by the National Research Council and the Institute of Medicine. The report of their deliberations, "Stem Cells and the Future of Regenerative Medicine,"1 had been finalized prior to, but was released one month after President George W. Bush announced federal funding of human ESC research limited to 64 existing stem cell lines developed by 10 companies and institutions.2 Despite calls from scientists and politicians to expand this pool, Bush has refused to do so, citing ethical considerations. The 59-page NAS report raises concerns over "potential human health risks" associated with existing human ESC lines because it says they are likely to mutate over time and because they were cultured in the presence of nonhuman cells or serum that might contain viruses. These concerns "necessitate continued monitoring of these cells as well as the development of new stem cell lines in the future," the report states. The potential problem of immune rejection is "a substantial obstacle to the success of transplantation" in the new field of regenerative medicine, for which stem cell research holds much potential. While SCNT is "ethically controversial," it can produce stem cell lines that are genetically identical to those of the donor and "should be actively pursued," the report states. Other options to overcoming rejection include genetic manipulation of the stem cells and developing "a very large bank" of cell lines through additional stem cell production. According to the report, peer-reviewed public funding "offers the most efficient and responsible means" of conducting this research. Noting that guidelines have been developed for conducting other ethically controversial research, such as for recombinant DNA experiments, the panel recommends creating a national human ESC advisory group "composed of exceptional researchers, ethicists, and other stakeholders." That panel should exist at the National Institutes of Health to "scrutinize" ESC research proposals to determine if they are "scientifically justified" and in compliance with federally mandated ethical guidelines. While the NAS report was finalized prior to Bush's Aug. 9 announcement, it was released afterward with only minor modifications. Bush announced that he would empanel a President's Council on Bioethics to be chaired by Leon Kass, a noted bioethicist at the University of Chicago. But that panel is not intended to oversee research grant applications. And Bush's ethical guidelines for public ESC research are fairly broad. To qualify for federal funding, the ESC lines had to be derived with the informed consent of donors, from excess embryos created solely for reproductive purposes, without any financial inducements to the donors, and had been created prior to the time of his announcement. Because stem cell research is still in its infancy, the NAS report calls for expanded studies on both embryonic and adult human stem cells. "There are important biological differences between adult and embryonic stem cells and among adult stem cells found in different types of tissue," the report notes. Accordingly, research on both cell types should be pursued. The Senate has been holding hearings to examine the adequacy of Bush's stem cell policy and a majority of senators support expanded research, including the derivation of additional new cell lines. The NAS report is likely to provide additional support for this position. But representatives in the House are less likely to approve any such approach and have voted to ban all forms of human cloning, including therapeutic cloning involving SCNT.3 Bush has promised to veto any legislation that would expand on his human ESC directives. In addition to Vogelstein, other NAS panel members included Barry R. Bloom, professor of immunology and infectious diseases, Harvard School of Public Health; Corey S. Goodman, professor of neuroscience, University of California; Patricia A. King, professor of law, medicine, ethics, and public policy, Georgetown University Law Center; Guy M. McKhann, professor of neurology and neuroscience, Johns Hopkins University School of Medicine; Myron L. Weisfeldt, professor and chairman of the department of medicine, Columbia University College of Physicians and Surgeons. Ted Agres (tagres@usa.net) is a freelance writer based in Washington, D.C. References 1. Stem Cells and the Future of Regenerative Medicine, Washington, DC: National Academy Press, September 2001, www.nap.edu/catalog/10195.html. 2. T. Agres, "Stem cells: steady momentum toward funding," The Scientist, 15[18]:8, Sept. 17, 2001. 3. T. Agres, "Cloning capsized?" The Scientist, 15[16]:1, Aug. 20, 2001.

NAS Report Likely Will Stir Debate

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