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Health Commentary
February 6, 2008
Embryonic Stem Cells: As important as ever
By Mike Magee, MD
In November, 2007, there was a great flurry of press activity around the announcement that stem cell researchers Shinya Yamanaka and James Thomson from Kyoto University in Japan and the University of Wisconsin in the U.S. had developed a method of deriving stem cells from human skin without the use of embryos.1 Many wondered whether these "induced pluripotential stem cells" might finally resolve the Bush Administration's embargo on federally funded progress in the field. As you will recall, on Aug. 9, 2001, the federal government announced that research on human embryonic stem cells created before this date would be supported by federal dollars; research on lines created later would not.2 By 2004, there were 21 lines of federally approved stem cells and 128 new embryonic stem cell lines around the world that did not qualify for support from the National Institutes of Health.3
The field of embryonic stem cell research is now 25 years old but it is moving at the speed of light.4 Mouse embryonic stem cells were first isolated in 1981. Over the following years, scientific questions and ethical concerns advanced side by side. The 21 federally approved stem cell lines that existed in 2004 were fundamentally flawed and had limited potential for use in clinical therapy. As Dr. George Daley of Harvard Medical School noted, "All were cultured in contact with mouse cells and bovine serum, which renders them inferior to newer lines, derived under pristine conditions, for potential therapeutic applications. Moreover, given the limited genetic diversity of the lines, transplantation of their products would face the same immune barrier as organ transplantation."3 Experts at the time generally agreed that the most important clinical questions could not be addressed by the federally approved stem cell lines. Using these lines, one could only explore generic questions about human embryonic stem cells, such as: What are the optimal culturing conditions? What factors promote growth and differentiation? How do genes modify and express themselves? The more important questions could only be addressed by means of lines that model specific diseases. Pursuing therapies required uncontaminated stem cells with lines genetically matched to the specific therapy needs of patients with diseases such as neurofibromatosis, Marfan's syndrome, fragile X syndrome, myotonic dystrophy, and Fanconi's anemia.3
What followed was significant interest in overseas ventures unencumbered by U.S. restrictions. U.S. states saw an opportunity as well and acted on it. By 2004, thirty states had generated 78 bills relating to stem cells. Nine states had legislation to approve state funding of this research, and California, Missouri, New Jersey, and Rhode Island had moved forward with concrete plans.5,6 Universities were active as well. Harvard committed $100 million in funds; Stanford, $12 million; University of California, $11 million; and the University of Minnesota, $8 million.6 They did so with considerable support from major U.S. medical and scientific organizations, including the American Medical Association,7 the Association of American Medical Colleges,8 the Institute of Medicine,9 the National Academy of Science,10 and 125 other U.S. medical, scientific, and patient advocacy organizations who first publicly voiced their support for federal funding of research using human pluripotent stem cells on July 29, 1999.11
Dr. George Daley captured what many medical and scientific leaders believed to have been the current reality at the time:
First, that the Bush Administration approach had "severely curtailed opportunities for U.S. scientists to study the cell lines that had since been established, many of which have unique attributes or represent invaluable models of human disease." Second, that "as research struggles forward in the absence of federal funding, the number of embryonic stem cell lines will continue to grow, creating ever more valuable tools that are out of the reach for U.S. scientists."3
In June, 2007, President Bush for a second time vetoed legislation that would liberalize the stem cell restrictions. In spite of this, the U.S. scientific community remains engaged. Over the past few years, $190 million has been invested privately in embryonic stem cell research. Nonprofit foundations like Project ALS and the New York Stem Cell Foundation are targeting specific diseases such as ALS, leukemia, Parkinson's Disease and diabetes. And states like Connecticut, Maryland, Illinois, New York and California have funded experiments in progress.4
What about those cutaneous cells? Will they replace the need for embryonic cells? Not according to Richard Murphy, the president of the California Institute of Regenerative Medicine. "We still think embryonic stem cells are the gold standard." Why? Because the process that creates the cutaneous cells introduces man made viruses into the cells that carry four genes that reset the cell's machinery. It is not known whether the introduction of these altered cells into humans might induce runaway cancerous growth. As Harvard University stem cell biologist Kervin Eggan says, "They are genetically changed in a way that should make us worry . . . Human embryonic stem cells will be better, even if they are more complicated politically".4
Now, with the breeze of political change in the air, it is time to redouble our efforts in stem cell research and fully support U.S. scientific leadership in the field.
For Health Commentary, I'm Mike Magee.
References
1. Stem Cell Breakthgrough. Washington Post. Nov. 24, 2007. A16.
2. The President's decision; Bush's address on federal financing for research with embryonic stem cells. New York Times. Aug. 10, 2001:A16.
3. Daley GQ. Missed opportunities in embryonic stem-cell research. NEJM. 2004;351:627-628.
4. Hotz RL. Stem Cell Researchers Claim Embryo Labs Are Still a Necessity. Wall Street Journal. January 4, 2008. B1
5. Murphy K. Embryonic stem cell debate bursts onto state level. Aug. 12, 2004.
6. Vastag B. Private efforts to pick up stem cell slack. JAMA. 2004;291:2059-2060.
7. Report 15 of the Council on Scientific Affairs (I-99): Embryonic/pluripotent stem cell research and funding. American Medical Association.
8. AAMC Applauds Congressional Support for Expanded Stem Cell Funding. Association of American Medical Colleges. April 28, 2004.
9. Stem Cells and the Future of Regenerative Medicine. Washington, D.C.: National Academy Press; 2004.
10. Public Funding of Stem Cell Research Enhances Likelihood of Attaining Medical Breakthroughs. National Academies. Sept. 11, 2001.
11. Letter from the research community to Representative John Porter. Life Issues Institute, Inc., March Of Dimes Update. July 29, 1999.
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