Stem cells hold promise of cures
By PAMELA SCHAEFFER
Stem cells, hailed as the greatest medical miracle since antibiotics, yet the new lightning rod for the abortion debate, are almost daily in the news.
Stem cells are the most versatile of cells: cells capable of reproducing themselves and also of growing into different kinds of body tissue. Stem cells are found in embryos and umbilical cords. Reservoirs of specialized stem cells also exist within our bodies, where they wait for the signal to go into action, repairing or replacing tissues damaged by age, injury or disease.
When someone cuts a finger, stem cells kick in to make new skin. They are also the reason injured lizards can grow new body parts.
If these building blocks of life can be controlled, they hold out the promise of cures for a variety of debilitating diseases, possibly within the next 10 years. Researchers hope stem cells will provide cures for diseases caused by cell failure and for repairing tissues that do not repair themselves. Heart damage, spinal cord injuries, Parkinsons disease, leukemia, bone marrow disease and diabetes are among diseases named in connection with stem cell research. Some researchers also hope that stem cells might eventually be prompted to make new organs for transplant organs that might not be rejected by the body.
Scientists say stem cell research may also hold the key to slowing down the aging process. Among dramatic recent breakthroughs in stem cell research, scientists have learned to rejuvenate telomeres, regulators that shut off stem cell division, a major factor in aging.
Researchers are working at stimulating stem cells into growth in the laboratory and learning how to direct them to diseased or damaged parts of the body. A major challenge is how to get the beneficial cells to their intended destinations without triggering immunities or other potentially serious side effects. Another is how to signal the cells to turn on and do what researchers want them to do once they get where theyre supposed to go. Still another is how to prevent the reproducing cells from turning into malignancies.
From the perspective of the Catholic church and others who oppose abortion, though, the research presents a serious moral problem. One major source of stem cells fortunately not the only source is human embryos, pitting potential cures for terrible afflictions against respect for human life.
The church doesnt have a position on stem cell research, but the church does have a position against taking human life for purposes of research, said Richard Doerflinger, associate director for policy development in U.S. Catholic bishops Secretariat for Pro-Life Activities.
Embryonic stem cells, isolated with private funds last year, are unspecialized pluripotent capable of producing many body tissues. Using private funds, embryonic stem cells have been obtained from aborted embryos and from fertility clinics, where parents donate for research spare embryos produced by in vitro fertilization.
Earlier this year, researchers found that huge stocks of stem cells can be reproduced from embryonic cells as easily as drug manufacturers make drugs. But as stem cells are harvested from embryos, the embryos are destroyed. To abortion opponents, taking cells from unwanted embryos is bad enough. Producing embryos exclusively for experimentation would be just as bad, if not worse. One of the big worries about stem cell research from the perspective of abortion foes is that it would provide a rationale for cloning human embryos for research.
Since 1995, the federal government has banned using federal funds for research on human embryos. But scientists and policy makers are pushing hard against the churchs opposition. In mid-September, the National Bioethics Advisory Commission urged Congress to remove the ban. But even those who favor using embryos fear that a public outcry would follow, with negative effects for research.
Meanwhile, President Clinton has endorsed an equally controversial loophole proposed by the National Institutes of Health: that federal funds be released for embryonic stem cell research as long as the cells are harvested from embryos with private funds.
Clinton said in a statement issued in July, No other legal actions are necessary at this time, because it appears that human embryos will be available from the private sector.
Abortion opponents regard that reasoning as tantamount to a sneak attack. Doerflinger said in a statement that the NIH is proposing a loophole to the federal law that will not fund the act of destruction itself but will reward those who destroy embryos, by paying them to develop the cells and tissues they have obtained by destructive means.
Fortunately for people hoping for cures, researchers discovered in a breakthrough early this year that stem cells from adult human bodies might be just as useful for healing as embryonic cells.
Until recently, specialized stem cells from adults were thought to be medically useless because of limitations their specializations imposed. But researchers, using techniques learned from the cloning of Dolly, the sheep, are learning that adult cells can be reprogrammed to behave like undifferentiated cells.
In recent months, announcements of new discoveries come almost weekly. In mid-September, for instance, bone marrow stem cells, thought to make only bone and blood, were coaxed into making muscle. Before that, bone marrow cells had produced liver and pancreatic cells. Further, stem cells have been found in places where they were formerly thought not to exist, such as in the human brain.
Doerflinger celebrates the potential. It does seem true that the embryonic stem cell by itself can produce more types of tissue than one adult stem cell can, but so what? If you can do the same things with three or four types that you can do with an embryonic stem cells, then the medical argument for destroying embryos disappears, he said. We would love to support research that would lead to treatments for disease, but the end doesnt justify any moral means.
National Catholic Reporter, October 22, 1999