New "Brain Cleaning" Technique Improves Memory in Aging Mice

Yahoo

29-03-2025

A team of researchers at Washington University School of Medicine in St. Louis has found that accelerating the brain's waste removal system could have tremendous implications for our memory.
As detailed in a study published in the journal Cell last week, the team found that by boosting the natural process of the brain cleansing itself of waste, they were able to improve memory in older mice.
Around a decade ago, scientists found that as the brain ages, a network of vessels surrounding it, known as the meningeal lymphatics, starts to slow down.
The system drains fluid and waste into the body's lymph nodes, where immune system cells constantly monitor for signs of disease or infection. But when it's impaired enough due to old age, the brain's resident immune cells, called microglia, have to jump into action instead, which can tax and overwhelm the brain.
By targeting the meningeal lymphatics, the researchers are hoping to overcome a major hurdle for other therapies designed to battle age-related cognitive issues and neurodegenerative conditions, including Alzheimer's and Parkinson's disease. Unlike therapies that struggle to get past the blood-brain barrier, this latest approach targets areas outside of the brain to gain access.
"The physical blood-brain barrier hinders the efficacy of therapies for neurological disorders," said Washington University pathology and immunology professor Jonathan Kipnis in a statement about the research. "By targeting a network of vessels outside of the brain that is critical for brain health, we see cognitive improvements in mice, opening a window to develop more powerful therapies to prevent or delay cognitive decline."
In an experiment, the team placed two identical black rods in a cage with old mice to let them play with them. On the next day, the same mice received one of these rods, as well as a silver rectangular prism. The idea is that older mice will spend roughly the same amount of time playing with either type of object, while younger mice will be more drawn to the novel trinket.
The team then used a treatment to boost the growth and function of the lymphatic vessels in some of the old mice. As a result, the researchers observed that they were spending more time playing with the shiny new object — suggesting their memory had improved, compared to other old mice that didn't receive the treatment.
"A functioning lymphatic system is critical for brain health and memory," said first author and Washington University postdoctoral fellow Kyungdeok Kim in the statement. "Therapies that support the health of the body's waste management system may have health benefits for a naturally aging brain."
The team suggests that the meningeal lymphatics treatment led to a reduction in the production of an immune protein called interleukin 6 (IL-6), which has previously been shown to affect brain health.
While plenty of work remains before we can demonstrate that the same approach could work in humans as well, the researchers are hopeful of discovering new ways to slow down the naturally aging brain.
"Targeting the more easily accessible lymphatic vessels that are located outside the brain may prove to be an exciting new frontier in the treatment of brain disorders," Kipnis said. "We may not be able to revive neurons, but we may be able to ensure their most optimal functioning through modulation of meningeal lymphatic vessels."
More on neurodegenerative diseases: Ozempic-Style Drug Slows the Progression of Alzheimer's Disease, Experiment Finds