There are something like 37 trillion cells in your body, each doing its designated task to keep you alive and healthy. But sometimes, some of those cells, particularly in our brains, simply become inert — these cells, called senescent cells, aren’t quite dead but they’re not performing their jobs, either.
Scientists have long thought the buildup of those cells were related to aging and diseases like cancer. New research published Wednesday in Nature shores up that link: the more senescent cells in a mouse’s brain, the more severe its cognitive decline.
Much of what we know about Alzheimer’s and other neurodegenerative diseases comes from retroactively examining a dead person’s or animal’s brain. This, however, was a controlled experiment, which means the researchers know the senescent cells actually caused the cognitive decline — we could rule out the chance that the higher senescent cell count was coincidental.
The researchers bred a type of lab rat that naturally developed senescent cells in their brain, thus experienced greater age-related cognitive decline. But when they started to prevent the cell buildup with a drug treatment, they saw that mice who received the treatment had healthier brains, plus reduced levels of cognitive decline and memory loss, than mice who didn’t receive the treatment and had a buildup of inert brain cells like normal.
It would be great if we could assume that human brains worked the same way, but so far there’s no evidence to suggest that it will. Senescent cells give rise to clusters of tau, a kind of protein that is difficult to break down and is linked to Alzheimer’s and Parkinson’s Disease.
So it’s easy to make the jump and assume that because can develop similar conditions, the drug treatment given to mice will also work for people. But often, medical research conducted on animals fails to generalize to human biology. So this certainly isn’t a cure for Alzheimer’s yet, but it might be a valuable avenue to explore in humans as well.
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