Key points from article :
Scientists studied blood cells from newborns to people in their 70s and 80s.
Adults under 65 had a wide range of red and white blood cells produced by 20,000 to 200,000 stem cell types.
In the over-65s, about half of their blood cells came from a measly 10 or 20 distinct stem cells.
Over time, mutations make stem cells grow faster, often producing lower-quality blood cells.
Change in the blood composition in older age increases the risk of blood cancers and anaemia, and impairs white blood cells to fight infection.
Underpinning why people often age healthily for decades before experiencing a more rapid decline in their 70s and 80s.
“...we see an option to use this to measure biological age,” - Peter Campbell, a senior author on the study.
Similar changes occur in organs throughout the body, from the skin to the brain.
Researchers now intend to understand why ageing leads to wrinkles and slower wound healing.
Elisa Laurenti, joint senior researcher, said chronic inflammation, smoking, infection & chemotherapy could produce stem cells with cancer-causing mutations.
Study by Wellcome-MRC Cambridge Stem Cell Institute published in Nature.
