An innovative theory of aging that explains why people can suddenly become thin after reaching the age of 70 has raised the prospect of new therapies for the decline and disease of old age.
Cambridge researchers have found a process that leads to a “catastrophic” change in the composition of the blood in old age, increasing the risk of blood cancer and anemia and reducing the effectiveness of white blood cells to fight infections.
Scientists believe that such changes occur in organs throughout the body, from the skin to the brain, which is potentially at the root of why people often age healthily for decades before experiencing a faster decline in the 1970s and 1980s. years.
“The exciting thing about this work is that there can be a common set of work processes,” said Dr. Peter Campbell, senior author of the study and head of the Cancer, Aging and Somatic Mutation Program at the Sanger Institute in Cambridge. “Ultimately, the goal would be to slow down or interfere with the aging process, but at least we see an option to use that to measure biological age.
Aging is a complex process, but many scientists suspect that the gradual accumulation of mutations in cells gradually impairs the body’s ability to function properly. Recent research shows that thinking is wrong or, at best, incomplete, and instead blames “selfish” cells that rise to dominance in old age.
Working with scientists at the Wellcome-MRC Cambridge Stem Cell Institute, Campbell and his colleagues studied blood cells in the age range from newborns to people in their 70s and 80s. They found that adults under the age of 65 have a wide range of red and white blood cells produced by a diverse population of 20,000 to 200,000 different types of stem cells in their bone marrow.
In the 65s, the picture was radically different. About half of their blood cells come from the measles 10 or 20 different stem cells, which drastically reduces the diversity of human blood cells, with consequences for his health.
Writing in the journal Nature, the researchers explained that while stem cells involved in blood production collect mutations over time, most of these changes are harmless. But problems arise when rare driver mutations cause stem cells to grow faster, often producing lower quality blood cells as a compromise. When a person is in his 30s and 40s, the advantage of aberrant stem cell growth is small, but at age 70 and older, these fast-growing cells begin to dominate blood cell production.
“Exponential growth explains why there is such a sudden change in weakness after age 70, why aging occurs at that age,” Campbell said. Faster-growing blood stem cells have been linked to blood cancer and anemia, but they also make people less resistant to infections and medical treatments such as chemotherapy.
“What we know about other organ systems is that many of the same observations apply,” Campbell added. Now researchers intend to look for the same process in the skin to understand why aging leads to wrinkles and slower wound healing.
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Dr Eliza Lorenti, an assistant professor at Wellcome-MRC Cambridge Stem Cell Institute and a joint senior researcher in the study, said that chronic inflammation, smoking, infections and chemotherapy can produce stem cells with mutations that cause cancer.
“We predict that these factors also lead to a reduction in the diversity of blood stem cells associated with aging,” she said. “There may be factors that can also slow down this process. We now have the exciting task of understanding how these newly discovered mutations affect blood function in the elderly, so that we can learn how to minimize the risk of disease and promote healthy aging.
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