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The amino acid valine, which people obtain by eating protein, appears key to the formation of blood stem cells. Mice deprived of the protein building block for two to four weeks stopped making new blood cells altogether, according to the new study, published Thursday in Science.
In lab tests the study showed human blood stem cells also appear to be as dependent on valine, the researchers said. If this proves true, depriving patients of the amino acid before a bone marrow transplant might spare them the necessity of chemotherapy or radiation, both of which destroy blood stem cells to make room for new, transplanted ones. But with these procedures one in 20 transplant patients dies, sometimes from complications linked to the toxic treatments.
Additionally, depriving certain leukemia patients of valine might even kill off the cells that are causing their cancers, says Hiromitsu Nakauchi, a senior author on the new paper. “If such a simple and relatively less harmful therapy could be used to treat leukemias, that would be great,” says Nakauchi, a stem cell researcher at both the University of Tokyo and Stanford University. “That’s what I’m hoping at the moment.” Nakauchi adds that he was surprised to uncover such a basic biological process. “I couldn’t believe it myself,” he says.
