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UW Scientists Increase Survival Of Stem Cells 11:54 PM 4/01/04 Ron Seely Wisconsin State Journal Using a chemical that allows some creatures, such as sea monkeys, to survive under extreme circumstances, scientists at UW-Madison have found a way to dramatically increase the survival rate of human embryonic stem cells. The important cells are notoriously finicky. When they are frozen for storage and transport and then thawed for use, only about 1 percent of the cells survive. But researchers in chemical and biological engineering have used a substance called trehalose so that 20 percent of the stem cells survive. Human embryonic stem cells are prized by researchers because they are undifferentiated - they haven't begun to change into specific cells for the heart or the pancreas or other organs. Scientists at UW-Madison and elsewhere are trying to coax the cells into growing into specific tissues to replace diseased cells and treat illnesses such as Parkinson's and diabetes. The cells have traditionally been preserved in the same way as other cells used for biomedical research: They are immersed in liquid nitrogen and frozen to minus 320 degrees Fahrenheit. But according to Sean Palecek, a UW-Madison professor of chemical and biological engineering, only about 1 percent of the cells survive the deep freeze. Researchers who want to use the cells must then use the few surviving cells to grow new colonies for their work. It is a long and painstaking process, Palecek said. Palecek also said scientists worry that natural selection - the tendency of more adaptable organisms to survive - is altering the stored cells in unknown ways. Researcher Juan de Pablo said scientists have known about the properties of the naturally occurring chemical called trehalose for some time. The chemical is a sugar that some animals and microbes secrete to help them survive extreme conditions such as dry or cold weather. The chemical, for example, is found in sea monkeys, the larvae of brine shrimp, which can go without water to the point of drying up and still survive. The UW-Madison researchers found a way to synthesize trehalose and mix it with the stem cells. "We're not very original," said de Pablo. "We copy nature whenever we can." The result was greater survival of the stem cells. In addition, de Pablo said, more of the cells remained in their undifferentiated state, an important quality for research. Now, de Pablo said, the researchers are trying to find ways to use trehalose to freeze-dry other kinds of cells, such as blood cells. Such an advance would allow for longer storage times and help alleviate chronic shortages of blood products, he added. Contact Ron Seely at [log in to unmask] or 252-6131 SOURCE: Wisconsin State Journal, WI http://www.madison.com/wisconsinstatejournal/local/71479.php * * * ---------------------------------------------------------------------- To sign-off Parkinsn send a message to: mailto:[log in to unmask] In the body of the message put: signoff parkinsn