Mild Traumatic Brain Injury Causes Lasting Blood-Brain Barrier Dysfunction

by Deborah Joye: For More Info, Go Here…

ngd- This leaking of molecules into the brain introduces noise and unpredictable instability in the way the brain functions…

What’s the science?

Players of contact sports such as American football are at particularly high risk for traumatic brain injury, which occurs when a sudden impact damages the brain. Repeated traumatic brain injury can result in neurodegenerative diseases later in life such as chronic traumatic encephalopathy. The brain’s microvasculature (the many small vessels supplying blood to the brain) can be damaged as a result of a traumatic brain injury. Specifically, dysfunction of the blood-brain barrier, which regulates which molecules can enter the brain, is connected to complications after traumatic brain injury and is also a hallmark of other brain disorders including stroke and epilepsy. To visualize how well the blood-brain barrier is working, researchers can measure how fast a tracer accumulates in the brain. Most previous studies have focused on tracer accumulation that happens very quickly and have seen very few differences. This week in Brain, Veksler and colleagues investigate more subtle blood-brain barrier dysfunction and demonstrate that a specific increase in slow-paced blood-to-brain transport is a hallmark of microvascular pathology that persists long after the initial brain injury.

What did they find?

The authors found that compared to healthy controls, football players had a much higher percentage of brain volume with abnormally high blood-brain barrier permeability. Increased leakiness was consistent across scans both during and after the season (roughly 6 months later). Some players showed a gradual decrease in abnormal permeability over time, while the other players actually showed an increase in permeability. An increase in blood-brain barrier dysfunction was associated with age, but not with number of concussions, years playing football, or scores on a concussion assessment test. The authors also found that certain regions of the brain were particularly susceptible to blood-brain barrier dysfunction, including the lefttemporal andoccipital lobes (involved in understanding auditory and visual signals, respectively), thethalamus (an important relay for sensory information), thebasal ganglia (important for movement), and white matter tracts (neuron tracts that connect different brain regions).

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