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Stem Cells' Origin, Versatility Drive Debate Over Research By Carol M. Ostrom - Seattle Times staff reporter Sunday, October 10, 2004 - Page updated at 12:00 A.M. Q: What are stem cells? A: Think of stem cells as blank slates with ambitions. Not only do they have the unique ability to self-renew over and over, they can generate cells for specific jobs in the body. Some kinds of stem cells can generate cells that beat a rhythm in your heart or that produce insulin in your pancreas gland. Left to their own devices, stem cells specialize naturally; in the lab, scientists are still figuring out what motivates them to "get a job." Q: Where do stem cells come from? A: There are two types: adult and embryonic. Adult stem cells are found in bone marrow and blood; very "young" adult cells are found in newborns' umbilical cords. Some scientists believe they've found stem cells in other types of tissue, such as skeletal muscle or fat, but that is disputed. Human embryonic stem cells are taken from embryos — fertilized eggs just a few days old, created by in vitro fertilization, but not implanted. Experts estimate there are many thousands of such "spare" frozen embryos. Q: Why are stem cells thought to be so important? A: In some tissues of the body, adult stem cells generate replacements for damaged cells. Because stem cells can become other kinds of cells, scientists believe stem cells could repair neurological damage or treat diseases such as diabetes, heart disease or Parkinson's disease. Figuring out what makes stem cells do what they do, Health and Human Services Secretary Tommy Thompson said last year, "can help fill in the blanks about what causes cells to misbehave in disease." Q: What's the difference between adult and embryonic stem cells? A: Scientists say embryonic stem cells, because they have the capacity to generate all types of cells, show the most promise. Adult stem cells found in a particular kind of tissue appear to be limited to becoming one of the types of cells found in that tissue, although some scientists believe that could be changed. Q: Why is research on stem cells controversial? A: Only research on embryonic stem cells is controversial. That's because a 3- to 5- day-old embryo must be destroyed to harvest the stem cells. While some believe this clump of cells — about the size of a typewritten period — is "potential life," others believe it already is a life. Still others say the fertilized embryo can't even be considered "potential" until it is implanted in the uterus. Supporters say the potential of embryonic stem cells to cure disease outweighs the destruction of the embryo, particularly because those spare embryos are destined for destruction in any case. Critics say that's a slippery slope. If that's the rationalization, they ask, why not remove organs from death-row inmates? Inevitably, they argue, unrestricted research would lead to creating living human embryos for the sole purpose of research. Q: What's the "compromise" the Republicans talk about? A: President Bush, in 2001, said he would allow federal funding only for research on existing embryonic stem-cell lines, because the "life-and-death decision" had already been made. A "line" means all the progeny of stem cells from a particular embryo, propagated in tissue culture over the years. Bush said more than 60 such lines were available. Q: So why is there still controversy? A: Bush's estimate of the number of cell lines available was instantly and widely disputed in the scientific community. Federal officials soon confirmed that only a fraction of those lines were actually available for use, and fewer still had proved they could become new cells. Scientists say some of those lines aren't of "good quality," and all have been nurtured with mouse "feeder cells" and aren't clean enough for human use. Q: What are scientists doing? A: Last year, the federal government funded three centers, including one at the University of Washington and Fred Hutchinson Cancer Research Center, to do research on the available federally approved lines, which the feds counted then as 12. The Exploratory Center for Human Embryonic Cell Research, housed at UW, got a $3.2 million grant. But scientists say the existing lines aren't enough. Private companies in the U.S. and abroad, as well as universities, using private money, are busily working to create new cell lines. Harvard University, using private funding, has created 17 new lines and has pledged to raise $100 million for a stem-cell institute. New Jersey created the New Jersey Stem Cell Institute with $6.5 million, and, next month, Californians will vote on a bond initiative to raise $3 billion for stem-cell research. Q: So are cures for Parkinson's, heart disease and diabetes just around the corner if only scientists could freely access plenty of embryonic stem cells? A: Most likely, "cures" are years, if not decades, away, although some scientists believe clinical trials in these diseases may occur in three to four years. Currently, there are mostly just hints of what could be, hints that lay people don't even know how to judge. Basic science is, let's face it, a slog. It's a testament to the enormous power of stem cells that so many scientists are eager to roll up their pant legs and wade into the murk for a journey that could well take the rest of their lives. SOURCE: The Seattle Times Local News, Oct 10, 2004 http://tinyurl.com/4ep3k * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn