An innovative theory of aging that explains why people may suddenly become fragile after reaching the age of 70 has raised the possibility of new therapies for the decline and diseases of old age.
Cambridge researchers discovered a process that causes a “catastrophic” change in the composition of the blood in old age, increasing the risk of blood cancer and anemia, and impairing the effectiveness of white blood cells in fighting infection.
Scientists believe that there are similar changes in the organs of the whole body, from the skin to the brain, which could be the basis for why people often age healthily for decades before experiencing a faster decline. between the ages of 70 and 80.
“What’s exciting about this work is that there may be a common set of processes in place,” said Dr. Peter Campbell, lead author of the study and head of the cancer, aging and somatic mutation program. Cambridge Blood Institute. “Ultimately, the goal would be to slow down or intervene in the aging process, but at least we see an option to use it to measure biological age.”
Aging is a complex process, but many scientists have suspected that the gradual build-up of mutations in cells gradually degrades the body’s ability to function properly. Recent research suggests that the thinking is incorrect, or at best incomplete, and blames the “selfish” cells that gain dominance in old age.
Working with scientists at the Wellcome-MRC Cambridge Stem Cell Institute, Campbell and colleagues studied blood cells from all ages, from newborns to people in their 70s and 80s. They found that adults under the age of 65 had 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 the bone marrow.
At 65, the picture was radically different. About half of their blood cells came from 10 or 20 different stem cells, drastically reducing the diversity of a person’s blood cells, with consequences for their health.
Writing in the journal Nature, the researchers explain that while the stem cells involved in the manufacture of blood pick up mutations over time, most of these changes are harmless. But problems arise when rare mutations in the “driver” cause stem cells to grow faster, often producing lower-quality blood cells as compensation. When a person is between 30 and 40 years old, the growth advantage of aberrant stem cells makes little difference, but at 70 and over these fast-growing cells come to dominate the production of blood cells.
“Exponential growth explains why there is such a sudden change in fragility after the age of 70, why aging comes at that kind of age,” Campbell said. The fastest growing blood stem cells are related to blood cancers 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. Researchers now intend to look for the same process on the skin to understand why aging causes wrinkles and slower wound healing.
Sign up for First Edition, our free daily newsletter, every weekday morning at 7:00 BST
Dr. Elisa Laurenti, an assistant professor at the Wellcome-MRC Cambridge Stem Cell Institute and a joint senior researcher in the study, said that chronic inflammation, smoking, infection and chemotherapy could produce stem cells with cancer-causing mutations. .
“We anticipate that these factors also cause a decrease in the diversity of blood stem cells associated with aging,” he said. “There may be factors that can also slow down this process. We now have the exciting task of figuring out how these newly discovered mutations affect blood function in the elderly, so that we can learn to minimize the risk of disease and promote healthy aging “.