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Virtual New York Saturday, 23 June 2001 22:09 (ET) Feature: Stem cells, adult and embryo By VICKI BROWER, UPI Science News WASHINGTON, June 23 (UPI) -- The science of stem cells is still in its infancy, but one of its biggest questions is as much philosophical as technical: Can stem cells from living adults offer the same promise in disease therapy, even cure, as those harvested from human embryos? While stem cell transplants worldwide have topped 1,000, much research remains between question and answer, say experts such as Princeton University's Ihor Lemischka. As the body's bank of generic replacement cells -- capable of differentiating on demand into almost any specific tissue -- stem cells dangle the promise of supplanting damaged or diseased tissue in a variety of disorders. Researchers hope to one day reproduce the body's intricate orchestration of stem cells to treat Parkinson's disease, cardiovascular disease, type 1 diabetes, spinal cord injury and other degenerative conditions. In the shorter term, the cells can be proving grounds for new drugs. Advocates of adult stem cells want to avoid the ethical conundrum of using 'extra' embryos from in-vitro fertilization or fetal tissue from aborted fetuses. Meanwhile, however, no one yet knows whether all tissues in adult bodies even contain stem cells, let alone how to control them. "The state of ignorance concerning our scientific understanding of stem cells currently is rather sobering," said Lemischka, speaking Friday at a meeting sponsored by the National Academy of Sciences. For example: -- Molecular analysis of gene expression and running functional DNA microchip arrays are only the beginning of gaining a better understanding of how plastic each type of cell is. -- Markers on the surface of stem cells used to identify and separate the cells from other cells and immunohistochemistry are both methods used to determine a stem cell's profile, but they are inadequate. -- Indeed, "we can get different results concerning the same stem cells depending on whether they are being tested in vivo or ex vivo, in one disease or another," said stem cell scientist Neil Theise, of New York University's department of pathology. "Until we can unravel gene expression of adult and human ESCs (embryonic stem cells) and compare the two, we can't say that adult stem cells can substitute for human ESCs," Lemischka said. Yet Congress has prohibited federal funding of any research that destroys or damages embryos. Nor is President Bush likely to reverse the ban, telling reporters soon after taking office that he believes "wonderful opportunities" exist for adult stem cell research, but his enthusiasm ends when it comes to harvesting aborted fetuses. While what appear to be stem cells have been found in numerous adult tissues -- including fat, bone marrow, liver, pancreas, and brain -- walking and talking like ducks may not be enough to declare them ducks said Stanford University's Irving Weissman, Ph.D., who isolated the first blood-derived human stem cells in the 1980s. For example, producing dopamine-producing neurons from adult stem cells has proven to be successful only in the short term in animals, said Dr. Ronald McKay, chief of the laboratory of molecular biology at the National Institute of Neurological Disorders and Stroke in Bethesda, Md. Dopamine is a brain messenger that is depleted in Parkinson's patients. "One solution is to go back to ESCs to see if we can push them to grow large numbers of long-lasting dopamine-producing neurons," McKay said. Yet McKay's institute is part of the National Institutes of Health, which cannot legally fund hESC research. Others at the conference decried such notions. "What is an embryo?" asked Kevin FitzGerald, a molecular biologist and a theologian who co-founded the organization Do No Harm. "Does it not have moral status? Who speaks for these cases in which their status may be in some doubt?" Although some scientists urge that the research be done on hESCs, one can never really say "enough research is done, now we know enough," added FitzGerald, a assistant professor of medicine at Chicago's Loyala University. That being the case, "need we pursue all possible lines of research?" He urged that scientists see that other avenues beside stem cell work be taken to cure disease, such as developing pharmaceuticals and gene therapies. Using excess IVF embryos for stem cell research is a political compromise between creating embryos for research purposes and banning research with them totally, said Boston University law professor George Annas. Even in the United Kingdom, which permits the creation of embryos for research purposes, only 189 were created last year. Annas stated that embryos are important not because of their innate characteristics, but because of their relationship to their creators, the parents. Decisions concerning the use of excess embryos for research should remain within the hands of the family, rather than the government, he said. Notwithstanding, decisions about legalizing hESC research will be made by Congress in the near future, said a Congressional aide. http://www.vny.com/cf/News/upidetail.cfm?QID=196861 * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn