Cells from embryos may heal diseased hearts, but universities have to deal with an uncertain science and charges of cloning people
Joshua M. Hare, a cardiac specialist at the University of Miami, certainly counts himself among the many stem-cell researchers who are eager and excited by President Obama’s expansion of federal support for studies using cells from human embryos.
He’s just not sure that embryos will actually work any better than the more common and less controversial source of stem cells that he’s already using.
“We’re quite far along” in devising a technique for repairing heart-attack damage using stem cells taken from the patient’s own bone marrow, said Dr. Hare, chief of cardiology and director of the Interdisciplinary Stem Cell Institute at Miami. Such a use of “adult” stem cells in cardiac patients could win regulatory approval within three to five years, he said.
Many university-based researchers, after enduring eight years of financial restrictions imposed in 2001 by President George W. Bush, believe that the happiness among them with Mr. Obama’s policy shift — and the potential of cures for paralysis or cancer or the growth of entire replacement organs — may soon give way to some tougher realities.
“Embryonic stem cells shouldn’t be viewed as the panacea that the public sees,” Dr. Hare said. Scientists need to temper the “high expectations about the lifting of this ban.”
The uncertainties aren’t limited to the scientific realm. As much as Mr. Obama tried to cast his March 9 announcement as a clear-cut victory for science over politics, researchers using embryonic stem cells still face possible government restrictions on their work. In just a few weeks, the National Institutes of Health is to begin defining rules to control the president’s expanded distribution of federal money for embryonic-stem-cell research.
Federal Ethics Rules
The NIH needs to set federal policy in several key areas, including rules for ensuring that the couple who create an embryo have given informed consent for scientific research, and rules governing the creation of genetically identical embryos, a procedure that some critics consider cloning.
The president’s decision to permit federal support of the research, while offering the NIH almost no additional guidance, “puts NIH in a very difficult position,” said Anthony J. Mazzaschi, interim chief scientific officer at the Association of American Medical Colleges.
NIH medical experts will set policy in an environment where the nation’s political divisions over stem-cell policy could be aggravated by confusion over the key scientific facts. A study published last year in the International Journal of Public Opinion by a team of communications researchers at the University of Wisconsin at Madison found religious values significantly outweigh scientific knowledge for most people when they form attitudes toward stem-cell research.
Human stem cells are valued by researchers because they have the potential to develop into any of the various types of cells that form the body. Those taken from an embryo are typically extracted after about four or five days of cell growth. In most cases, the embryos were frozen for couples as part of a continuing attempt to start a pregnancy. Experimentation with those embryos is opposed by some people who regard an embryo as a form of human life.
The debate, and scientists’ doubts about the expertise of those involved in it, extends to Capitol Hill, where lawmakers are considering additional revisions to federal stem-cell policy. One longstanding element of federal law, renewed by Congress and the president in the same week Mr. Obama lifted Mr. Bush’s limits on stem-cell research, prohibits the use of federal money to create or destroy an embryo.
Scientists express little concern about that provision, known as the Dickey-Wicker Amendment, in part because its scientific imprecision has let them sidestep its intent by purchasing embryonic stem cells through third-party suppliers.
Universities and researchers have also tried to work around Mr. Bush’s 2001 restrictions. Those rules prevented scientists from using federal money to work on stem-cell lines created after Mr. Bush’s announcement. That left researchers with only 21 cell lines, which sustained damage as they aged.
Scientists took elaborate steps to manage the restriction, such as placing red tags on laboratory equipment purchased with federal money and sometimes establishing entirely separate lab facilities. Others simply avoided or withdrew from embryonic-stem-cell research, fearing the legal and financial hassle. Some moved their work overseas. A few states, led by California, offered their own money to spur work with embryonic stem cells.
Scientific Breakthroughs
Then the science itself shifted. In 2007 a Japanese researcher, Shinya Yamanaka, developed a method for reprogramming skin cells to behave like stem cells. His discovery of “induced pluripotent” stem cells, combined with known uses of adult stem cells taken from bones and other parts of the body, may eventually short-circuit the politically charged debate over embryos.
Dr. Hare is one of those holding out hope. His injections using adult stem cells have shown signs of repairing the scar tissue and other damage caused by heart attacks. Stem cells, injected into a damaged body part, can stimulate the growth of new cells, sometimes with the help of modifications that “teach” the stem cell what it should become, he said. Dr. Hare’s experiments with heart-attack patients have moved past initial safety testing and into studies of their actual efficacy.
“We haven’t proven this beyond a shadow of a doubt,” Dr. Hare said, “but the cells appear to do the right thing.”
Despite such confidence, Dr. Hare is among the researchers grateful that they can now check whether embryonic stem cells might work even better than adult stem cells. Those other scientists, he said, include a Miami colleague, W. Dalton Dietrich, who has been testing whether cells taken from nerve fibers can be used to help paralyzed people walk by repairing breaks in their spinal cords.
Just two months before Mr. Obama lifted the restrictions, the Food and Drug Administration approved an application by the Geron Corporation to test an embryonic-stem-cell treatment for paralysis on humans. Now Dr. Dietrich, scientific director of the Miami Project to Cure Paralysis, can seek federal support to see if his technique might work when using embryonic stem cells.
And in Mr. Bush’s home state of Texas, the chairman of the department of neuroscience at the Baylor College of Medicine, Michael J. Friedlander, said he hopes Mr. Obama’s action will push forward an effort to help U.S. soldiers recover from traumatic brain injuries.
Dr. Friedlander uses electrical stimulation of the brain toward that goal in a Pentagon-financed project. But some of his colleagues in a wider partnership, involving the University of Texas and a local veterans hospital, are also testing whether injections of modified stem cells might help injured brains regrow lost cells or rebuild electrical connections, he said. The possible addition of embryonic stem cells to the project might contribute to an eventual treatment, he said.
“Both have limitations,” Dr. Friedlander said, referring to embryonic and adult stem cells, “and while the debate on this subject continues to rage about which method is best, the reality is that the scientists involved with it understand that we don’t fully appreciate and understand yet which method is best for a particular problem. That’s why it’s in the realm of research.”
Cloning Controversy
Embryos at the very start of the human life cycle, a stage before cells begin to differentiate, are believed to produce stem cells best able to transform into other types of cell or to grow into organs. Problems with organ rejection perhaps can be overcome by transferring genetic material from the cell of the patient into an embryonic stem cell.
That raises an opportunity, and another controversy. The transfer of one person’s genetic coding into an embryonic stem cell holds the promise of breakthroughs in a variety of treatments, including pharmaceutical production, because the transfer would let researchers test their ideas on unlimited copies of a human cell with the same genetic information. Those exact duplicates could be especially valuable in studies aimed at curing a particular genetic defect.
But such duplication is regarded by some critics as cloning. Many researchers disagree, saying that cloning would occur only if the cells were placed in an embryo that was then implanted in a woman to create a pregnancy.
Mr. Obama, in the one clear limit he did set in his March 9 announcement reversing Mr. Bush’s policy on stem cells, promised to ensure that the government “never opens the door to the use of cloning for human reproduction.” The details of that promise were left for the NIH to decide.
The agency also must establish rules and systems for tracking lines of stem cells as researchers grow and share them, and for ensuring that those stem cells originated with couples who approved the research and understood what it meant.
Scientific Competition
NIH officials, given 120 days by Mr. Obama to develop an overall set of guidelines, said they had little doubt they could meet his July 7 deadline. They have declined to offer details of their plan other than to say they would rely on existing ethical standards, including the annual set of guidelines for using human embryonic stem cells published by the National Academies. An initial public draft is expected from the NIH in May.
James A. Thomson, a professor of anatomy at Wisconsin whose identification of human embryonic stem cells in 1998 ignited the global rush into this research, said he is confident that the NIH will create a level playing field that will let an expanded field of academic scientists determine what source of cells works best for which medical need.
Much of the political difficulty facing Mr. Obama and his allies in Congress over the issue can be traced, ironically, to the previous federal limits on research, which have prevented the public from seeing much-anticipated medical breakthroughs with stem cells, he said.
“There’s been 10 years of experience with human embryonic stem cells, and they’re doing everything they’re supposed to do,” said Dr. Thomson. The general public, however, has “a disconnect for how long the research takes.”
Even if the alternative technique for using skin cells discovered by Dr. Yamanaka proves superior in many or all cases, research involving embryonic stem cells won’t be wasted, because the knowledge should be transferable, Dr. Thomson said.
“I think it’s time to let that competition just kind of play out,” he said. “If these newer reprogrammed cells are fatally flawed in some way, scientists are going to figure it out. If they’re identical, they’re going to figure that out, too.”
http://chronicle.com Section: The Faculty Volume 55, Issue 29, Page A12
