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Aging Stem Cells Linked to Blood Diseases

Posted on: Wednesday, 6 June 2007, 18:00 CDT

Aging stem cells in the blood may lead to genetic mutations that cause blood diseases in older people, U.S. researchers said Wednesday.

That conclusion is the result of a mouse study done by researchers at Stanford University School of Medicine in Palo Alto, Calif.

The idea is that, over time, accumulated DNA damage progressively diminishes the cell's ability to perform its normal function, said Derrick Rossi, co-first author of the study.

Rossi isolated stem cells from the bone marrow of both young and old mice, then stained the cells with a chemical that clings to a protein linked to DNA damage, a process that flagged any DNA damage present.

Rossi saw that young stem cells from normal mice contained no stain and therefore little or no DNA damage, but in contrast, older stem cells had significant damage.

The researchers concluded that blood-forming stem cells do 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.

The study 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 study author Irving Weissman, director of the Stanford Institute for Stem Cell Biology and Regenerative Medicine and of the Stanford Comprehensive Cancer Center.

The study is published in the June 6 issue of Nature.

Source: United Press International

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