Aging vessels connecting the brain and the immune system play critical roles in both Alzheimer’s disease and the decline in cognitive ability that comes with time, new research reveals. By improving the function of the lymphatic vessels, scientists at the University of Virginia School of Medicine have dramatically enhanced aged mice’s ability to learn and improved their memories. The work may provide doctors an entirely new path to treat or prevent Alzheimer’s disease, age-related memory loss and other neurodegenerative diseases.
The research is the latest from the lab of pioneering neuroscientist Jonathan Kipnis, whose team discovered in 2015 that the brain is surrounded by lymphatic vessels – vessels science textbooks insisted did not exist.
That discovery made headlines around the world and was named one of the year’s biggest breakthroughs by the journal Science, yet Kipnis sees his team’s new finding as their most important yet.
“When you take naturally aging mice and you make them learn and remember better, that is really exciting,” he said. “If we can make old mice learn better, that tells me there is something that can be done. I’m actually very optimistic that one day we could live to a very, very, very old age and not develop Alzheimer’s.”
How the Brain Cleans Itself
It turns out that the lymphatic vessels long thought not to exist are essential to the brain’s ability to cleanse itself. The researchers’ new work gives us the most complete picture yet of the role of these vessels – and their tremendous importance for brain function and healthy aging.
Kipnis – who chairs UVA’s Department of Neuroscience and directs its Center for Brain Immunology and Glia, or BIG – and his colleagues were able to use a compound to improve the flow of waste from the brain to the lymph nodes in the neck of aged mice. The vessels became larger and drained better, and that had a direct effect on the mice’s ability to learn and remember.
“Here is the first time that we can actually enhance cognitive ability in an old mouse by targeting this lymphatic vasculature around the brain,” Kipnis said. “By itself, it’s super, super exciting, but then we said, ‘Wait a second, if that’s the case, what’s happening in Alzheimer’s?’”