EMBRYOLOGY:
Immortal Cells Spawn Ethical Concerns
Developmental biologists grabbed headlines this year by growing a kind of human embryonic cell that can be coaxed to become many different types of human tissue. The work, which starts with cells from human embryos, may lead to safer tissue transplants, but it also fired up a debate about the ethics of using embryos in research. Coming on the heels of Dolly, the cloned sheep and 1997's Breakthrough of the Year, the research offers another dramatic example of how rapid scientific progress is ushering in a new era of control over human reproduction and development--and sparking a host of new ethical questions for a largely unprepared public.
Indeed, although biologists are eager to follow up on the results, legal questions put the work outside the reach of U.S. taxpayer-financed labs. It may take months to resolve the ethical and legal issues, according to members of Congress and National Institutes of Health officials who met at a Senate inquiry in December.
The big news came in November, when two U.S. academic groups reported that they had isolated "embryonic stem cells" from human embryos and fetuses. As these cells divide, they give rise to more specialized cells that can become almost any kind of tissue in the body, including bone, gut, or blood cells.
New neurons. These neurons were derived from human embryonic stem cells. CREDIT: SHUNPING WANG
If the cells live up to their promise, they could lead the way to custom transplant tissues that won't trigger a patient's often-lethal immune response. Already these techniques have produced replacement cells that were successfully grafted onto a damaged mouse heart, and analogous experiments may be tried before long on a human heart. Eventually, lab-grown neurons may be transplanted into the brains of people with Parkinson's disease. For now, the cells will be used mainly to study human development and gene expression and test cellular reactions to candidate drugs.
But before any of that happens, more researchers will need to leap into this field--and as of now, taxpayer-financed labs in the United States are hesitant to do so because of hostile federal rules. Cell lines derived from embryos cannot now be used in federally funded research, although the use of tissue from medically aborted fetuses may be permitted. And laws vary widely around the world. In Britain publicly funded researchers can use early embryos, but both private and public labs must obtain a license first; France, Germany, Norway, Denmark, and Austria are even more restrictive.
To avoid tangling with federal regulators, both stem cell developers this year relied entirely on private support from the Geron Corp. of Menlo Park, California. The universities whose faculties did the research hold patents on the technology, which is to be commercially developed by Geron. Thus these cells, which--in theory--have the potential to develop into a human embryo, are treated as commercial products, a notion that sparked concern in a U.S. Senate hearing in December. Committee members said they plan to investigate this aspect further next year, and President Clinton has asked his National Bioethics Advisory Commission to investigate; their complete review is due in mid-1999. Research on these embryonic cells may be dampened by government strictures, but debate is sure to flourish.
Reading:
E. Marshall, "A Versatile Cell Line Raises Scientific Hopes, Legal Questions," Science 282, 1014 (6 November 1998).
E. Marshall, "Use of Stem Cells Still Legally Murky, But Hearing Offers Hope," Science 282, 1962 (11 December 1998).
E. Marshall, "Britain Urged to Expand Embryo Studies," Science 282, 2167 (18 December 1998).
