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The source of this article is the Kansas City Star: http://tinyurl.com/5wrja Posted on Thu, Feb. 17, 2005 Scientists discover how to remove animal cells in stem-cell research BY JOHN FAUBER Milwaukee Journal Sentinel MILWAUKEE - (KRT) - For years, the promise of embryonic stem cells has been corrupted by the inescapable reality that most, if not all, lines of those cells are so contaminated by animal cells that they never would be usable for human research. But scientists at the WiCell Research Institute and University of Wisconsin-Madison may have leaped over a substantial hurdle in the dream to someday use those cells to treat human diseases. Writing Thursday in the journal Nature Methods, they say they have figured out a way to eliminate the mouse feeder cells that are used to culture embryonic stem cells and keep them in their desired immature state. While mouse cells have helped maintain embryonic stem cells, they also are a potential source of animal pathogens that could be dangerous to people. Now Madison researchers say a substance known as fibroblast growth factor 2, or FGF2, does essentially the same thing as the mouse feeder cells - keeping the embryonic stem cells in their desired blank-slate state. As a pure protein, FGF2 would not carry the risk of being contaminated by viruses or other animal pathogens. "It removes one of the major impediments," said John Lough, a stem cell researcher and professor of cell biology, neurobiology and anatomy at the Medical College of Wisconsin. "This is a very important finding." Lough said mouse feeder cells probably secrete hundreds of proteins. "What they've done is replace that with a single molecule," he said. He said researchers have long been concerned about so-called zoonotic disease transmission to humans that could be caused by mouse feeder cells. They used mouse cells because they helped maintain embryonic stem cells in the pluripotent state, meaning they are able to become any of the more than 200 cells types found in the human body. Lough said another challenge for researchers is to zero in on the best ways to coax those cells to become specific cell types. "If you want to repair the liver, you've got to be able to turn them into liver," he said. The better scientists are able to define the environment in which stem cells are maintained, the better they will be able to do that, he said. The University of Wisconsin, which first isolated human embryonic stem cells in 1998, has developed five lines of stem cells for research. Those - and most likely all other stem cell lines around the world - still contain two other potential sources of animal contamination. One is a product know as Matrigel, which is extracted from mouse tumor cells and is used to coat culture dishes. The other is a substance known as serum replacement, which is made from cow blood. Ren-He Xu, senior scientist at the WiCell Research Institute and lead author of the study, said he expects to be able to replace those with non- animal substances in the next six months to one year. "We are intensively working on this," Xu said. "We are on the way." When that happens, WiCell plans to create new lines of human embryonic stem cells that are free of animal contamination, Xu said. "We'll need to derive new lines with new medium," he said. However, under President Bush's policy, federal money can't be used to create new lines of human embryonic stem cells. Some people have moral objections to using federal dollars because doing so involves destroying embryos that are about a week old. "We'll need to get private funding for that," Xu said. While the WiCell/UW study is an important development, more trials among various labs will be needed to determine the robustness of new cell culturing methods, according to a New and Views article accompanying the study. "There is a very strong case for collaboration and cooperation internationally in tackling this important challenge for the field," wrote Martin Pera, a researcher at the Monash Institute of Medical Research and the Australian Stem Cell Centre. © 2005, Milwaukee Journal Sentinel. ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn