04 Oct It's 99 percent certain: Research cannot rely on adult stem cells alone
“MADISON—In the first debate of Wisconsin’s U.S. Senate campaign, Republican Tim Michels dismissed scientific research using human embryonic stem cells as little more than an inconsequential sideshow. Michels said he supports the “99 percent” of stem cell research that uses adult stem cells or cells from umbilical cords—but not the “1 percent” that uses human embryonic stem cells.
“Technology is going to move us away from that (embryonic stem cell research) being necessary,” Michels declared in his Oct. 1 debate against Democratic incumbent Russ Feingold.
While some may respect Michels’ moral convictions against research using human embryonic stem cells, he is 99 percent wrong to suggest that adult stem cell research alone with yield cures for diseases or help to develop safer, more effective drugs. Very few, if any, scientists will argue for closing off one research path in favor of another. In general, that’s not how science works—and it’s especially true when it comes to stem cell research.
Embryonic stem cells are the body’s core cells. They are “undifferentiated,” which means they have yet to change into a specific cell type. Because they have the ability to form any adult cell and can proliferate indefinitely in culture, stem cells could potentially provide an unlimited source of specific, clinically important adult cells such as bone, muscle, liver, blood, neural and pancreatic cells.
For that reason, scientists believe embryonic stem cells may unlock treatments or cures for people suffering from spinal cord injuries, diabetes, Parkinson’s, heart disease, Lou Gehrig’s, Alzheimer’s or other diseases and conditions. At the UW-Madison, where developmental biologist James Thomson was the world’s first scientist to successfully isolate and culture embryonic stem cells, research revolves around producing cells for bone marrow, insulin-producing pancreatic islet cells, neural tissue, heart tissue and muscle.
Embryonic stem cell technology, combined with the recent “mapping” of the human genome system, also has the potential to speed up the often-laborious and imprecise process of drug discovery. It also offers a fascinating glimpse into the earliest stages of human development, which may lead to discoveries surrounding birth defects and infertility.
In addition to embryonic stem cell research, scientists are trying to tap into the potential of adult stem cells.
Adult stem cells are thought to exist in at least 13 of 220 body tissues. Adult stem cells constantly produce new skin, intestinal lining, red blood cells and more. They are remarkably versatile. Adult stem cells in bone marrow, for instance, can be channeled to become fat cells, cartilage-forming cells or bone-forming cells. However, they are tough to work with from a research perspective.
“One of the problems of working with adult stem cells is that they are very rare and difficult to isolate,” concluded a report by the Massachusetts Institute of Technology. “Researchers who attempt to grow adult stem cells in the laboratory find they cannot increase the number of stem cells in culture, because when adult stem cells divide, they produce both new replacement stem cells and regular cells, which quickly proliferate and vastly outnumber the stem cells.”
Adult stem cells divide to replace themselves and create “daughter cells,” which either transform themselves immediately or divide into other lines that do so.
In part because they relentlessly insist on doing nature’s work, adult stem cells pose serious problems in research settings. They are scarce and have not been found in many organs or tissues. They do not live long in culture. They have shown little ability to proliferate into quantities that can be effectively used in research or therapy. They can be dangerous to extract from some organs, such as the brain. As humans age—when such cells are needed the most—they become ever rarer. Adult stem cells may also exhibit genetic defects from exposure to toxins and sunlight. Perhaps most important, the targeted disease for stem cell therapy may already be lurking in the adult stem cells.
Because of restrictions on how federal research dollars can be used, more money is being focused today on adult than embryonic stem cell research. But that’s in the United States only, and the spending ratio here is more like 50-50 than 99-1.
Few scientists would bet on embryonic stem cell research alone—and fewer still would place all their hopes on adult stem cell research. If a candidate opposes human embryonic stem cell research on moral grounds, that’s one thing. But a candidate should be careful not to distort what’s actually happening in the nation’s laboratories.
Still is president of the Wisconsin Technology Council. He is the former associate editor of the Wisconsin State Journal in Madison.
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