Grappling with concussion: discovery, policy, and practiceBMJ 2013; 346 doi: http://dx.doi.org/10.1136/bmj.f1693 (Published 15 March 2013) Cite this as: BMJ 2013;346:f1693
- Bob Roehr, freelance journalist
- 1Washington, DC
Injury to the brain from concussion and other lesser trauma might result at least in part from damage to the blood-brain barrier and a complex immune feedback loop that mimics autoimmune disease. Evidence supporting the theory was gathered through collaboration between researchers at the University of Rochester Medical Center and the Cleveland Clinic and published this month in PLoS ONE.1
The blood-brain barrier is best known for preventing some molecules in the blood, most notably some drugs, from entering into the brain compartment. But it also works the other way, keeping some proteins unique to the brain from entering into the rest of the body. One of these is S100B, a protein associated with traumatic brain injury.
The study looked at blood samples from 67 college football players before and after a game; none had experienced a concussion. In the samples taken after the game small amounts of S100B and other brain proteins that are not supposed to be in the rest of the body were found. Looking back at video footage of the game, higher levels of S100B correlated with exposure to rougher contact during the event.
“The blood-brain barrier opens up, after every game, every practice, every scrum. Small amounts of protein, in particular S100B leak into peripheral circulation,” explains Jeffrey J Bazarian, associate professor at the University of Rochester Medical Center and coauthor of the paper. The immune system treats them like invaders; “It looks like the body forms antibodies to that protein because it is not used to seeing that protein in the peripheral circulation.
“We speculate that when the blood-brain barrier opens up again, those antibodies enter the brain and potentially do damage.” He says this new way of thinking “opens …