June 15, 2004
The recent death of President Ronald Reagan, who struggled for 10 plus years with the mind-robbing ravages of Alzheimer's disease, has spurred calls for expanded research into the use of embryonic stem cells. This controversial form of medical therapy has been proposed as a treatment for Alzheimer's disease and other grave disorders. But whether stem cells will show promise against these maladies will require much additional research.
Stem cells from human embryos have generated enthusiasm because they possess a unique property: Unlike other cells, they can morph into many different types of body tissues. Some studies suggest, for example, that embryonic stem cells injected into a damaged heart may grow into healthy new heart cells. Scientists hope that one day they may be able to inject stem cells into a brain damaged by Alzheimer's and regenerate healthy new brain cells.
But that day is likely a long way off. The brain is composed of many billions of nerve cells. A large number and variety of these cells become damaged in Alzheimer's, and scientists are only now beginning to unravel the complex mechanisms that cause the disease. Finding a treatment that haltsand actually reverses or compensates forthe damage done by Alzheimer's is a daunting demand.
Ethical and political issues surrounding the use of human embryonic stem cells further complicate the effort. Such research would require using spare embryos donated from fertility clinics, where they are kept frozen. Stem cells would be taken from the embryos, grown in a dish, and implanted into a patient's brain. In the process, the embryos would be destroyed, a practice that many people do not find morally acceptable. However, others point out that these "excess" embryos from fertility clinics would be destroyed anyway.
President Bush in 2001 prevented the government from funding research using human embryonic stem cells except for stem cell lines that had already been developed. But many scientists counter that stem cell research should be expanded, a sentiment recently echoed by former First Lady Nancy Reagan.
Private groups in the U.S. and abroad continue to develop new lines of stem cells from embryos and to study their potential uses for Alzheimer's and other ailments. Potentially less controversial techniques are also being pursued. Some clinics, for example, are experimenting with cells from defective embryos that would never be viable. Other groups are working with stem cells obtained from adults, rather than embryos, though adult cells may not be as effective as those from embryos.
In addition to Alzheimer's, other treatments for which stem cells may hold promise include:
- Parkinson's disease, a serious movement disorder caused by the progressive death of nerve cells in the brain, causing rhythmic shaking, slowness, stiffness, and loss of coordination.
- Spinal cord injuries, like the kind suffered by paralyzed Superman actor Christopher Reeve after falling off a horse.
- Type-1 diabetes, an immune-related disorder affecting many body systems that is caused by the loss of specialized insulin-producing cells in the pancreas and the inability to control levels of blood sugar.
Most experts believe that it may be years before useful new treatments for Alzheimer's and other diseases are developed based on stem cells. Working toward that goal requires painstaking research into the complicated cellular mechanisms that take place in the brain, one of the most complex of all human organs.
In addition to stem cells, many other promising forms of basic research continue at The Fisher Center for Alzheimer's Research at The Rockefeller University, funded by The Fisher Center for Alzheimer's Research Foundation, which also funds other leading medical centers. For more on ongoing research in Alzheimer's disease, visit www.ALZinfo.org.