Growing Stem Cells - Mean anything to us AA folkds?

From: bruce
Email: sales@aebiz.com
Date: 6/4/2001
Time: 8:35:08 AM
Remote Name: 24.169.74.83

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http://www.cbsnews.com/now/story/0,1597,53267-412,00.shtml (Reuters) An extra hormone can help elusive blood stem cells multiply and thrive outside the body, offering cancer patients and others a ready supply of the life-giving cells, scientists say. Doctors have long been trying to find a way to grow large numbers of stem cells, which give rise to red blood cells and the white blood cells of the immune system and are used to replace bone marrow after intense chemotherapy or radiotherapy. The cells are very difficult to find and filter out of the blood, and usually die after about a month in a laboratory dish. But Mayumi Yagi, Stephen Bartelmez and colleagues at the University of Washington in Seattle and the Veterans Affairs Puget Sound Health Care System said they had coaxed stem cells into living in the lab for up to four months. Writing in the Proceedings of the National Academy of Sciences, they said they had transplanted their four-month-old cells into mice whose bone marrow was destroyed by radiation, and saved the lives of the mice. "It's now almost a year later, and these animals are walking around as healthy as they can possibly be. We can't find anything wrong with them," Bartelmez said in a statement. "The implications of this are huge," he added. "It was the first demonstration that stem cells could be substantially expanded outside of an animal." One of the secrets was thrombopoietin, a hormone the team tested to try to encourage the growth of platelet cells involved in blood clotting. Bartelmez, who studies stem cells, found them flourishing in the cultures. "I looked at this culture and I just about fell over. It was totally unheard of," he said. He said this might offer a new source of stem cells for patients whose bone marrow has been destroyed by cancer treatments. The harsh treatments often kill off the cancer, but they also leave a person without an immune system or a way to produce new blood cells. Infusions of stem cells can replace their bone marrow in days. The problem has been getting enough of the elusive cells. A company based in Ann Arbor, Michigan, Aastrom Biosciences Inc. (ASTM.O), has a patented system for growing and multiplying such stem cells. The AastromReplicell system, which attempts to replicate the bone marrow environment, is available in Europe and being tested in patients in the United States. Bartelmez said the research also has implications for a more experimental use of stem cells -- delivering gene therapy. The idea would be to introduce normal genes into the blood stem cells of patients suffering from genetic diseases and try to recolonize the patient's bone marrow with these genetically engineered genes. "If we can insert a normal gene into these dividing stem cells, we may in many cases cure the disease," Bartelmez said. "One reason nobody has been able to do this up until now is because no one can get stem cells to divide outside the animal and just keep dividing. This discovery may be an important step for gene therapy to become a practical reality." Blood stem cells are just one of several types of stem cells. Researchers have also isolated neural stem cells from the brain, and stem cells that form muscle, cartilage, fat and other tissue. Then there are embryonic stem cells, which come from early embryos and which have the potential to become any kind of cell at all. But their use is controversial, and some scientists think techniques like that reported by the University of Washington team might offer alternative sources. Copyright 1999 Reuters Limited. All Rights Reserved.