Researchers at the Stanford University School of Medicine report that blood-forming stem cells accumulate DNA damage with age even though they rarely divide, and that damage is passed on to the blood and immune system cells they make. These findings in mice could explain the origin of blood cancer (leukemia) and immune dysfunctions that occur as humans age.
“This and our previous work points out why older people are more likely to get blood diseases, such as leukemia or anemia, and are less likely to make new antibodies that would protect against infections like the flu,” said senior author Irving Weissman, MD, director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine and of the Stanford Comprehensive Cancer Center.
Researchers had thought that mutations were unlikely to underlie aging in blood-forming stem cells because they very rarely divide, and most mutations crop up during division. The infrequent divisions were believed to protect the cells from acquiring new mutations. The Stanford research team tested that idea in two different sets of experiments in mice.
Illustration: Stanford School of Medicine.
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