Even mild concussions cause severe and long-lasting impairments in the brain’s ability to clean itself of toxins, and this may seed it for Alzheimer’s disease, dementia and other neurodegenerative problems, new research from the University of Virginia School of Medicine reveals. The findings help explain why TBI is so harmful and why it can have such long-term effects. The research also suggests that certain patients are at greater risk of a decline in brain function later in life, and it paves the way for new and better treatments. “This reinforces the idea that you have to give people an opportunity to heal. And if you don’t, you’re putting yourself at a much higher risk for long-term consequences that you might not see in a year but could see in a couple of decades.”
Lukens’ research identifies a previously unknown consequence of TBI that can have long-lasting effects. When the brain swells, it presses against the skull; trapped in-between are tiny lymphatic vessels that clean the brain. This pressure on the vessels, the UVA researchers found, causes serious and long-lasting impairment of the brain’s ability to purge itself of toxins. Working with lab mice, one of the best models of TBI available, the scientists found the impairment could last at least two weeks — a long time for mice — and possibly much longer. These lymphatic vessels were identified by Jonathan Kipnis, PhD, and his collaborators at UVA in 2015. Until then, medical textbooks insisted the vessels did not exist and that the brain was “immune privileged,” meaning that it did not interact with the immune system. Kipnis’ discovery changed all that, and he has since determined the vessels play important roles in both Alzheimer’s and the cognitive decline that comes with age.