News From the Cause
Deciphering the Blasted Brain (US NEWS & WORLD REPORT)
July 27, 2011
When Kevin Parker was on patrol in Afghanistan in 2002, he saw many troops develop traumatic brain injuries after being injured by an improvised explosive device. Parker met soldiers who were the recipients of more than a dozen blasts, and a 2008 study by the RAND Corporation found that nearly 20 percent of troops deployed to Iraq and Afghanistan reported suffering from TBIs—traumatic brain injuries—during combat. When biophysicist-turned-Army-major Parker returned from combat duty, he took a position at Harvard University's Wyss Institute and began to study TBIs on the cellular level.
In the past week, Parker and colleagues published two papers that identify a protein that transforms the mechanical force of a blast into neuron damage, causing a TBI.
"It's an excellent study," said Robert Langer, a chemical engineer at the Massachusetts Institute of Technology in Cambridge who was not involved in the research. "It creates a new role for how these proteins may affect nerve injury."
A TBI can occur whenever the head is struck by an outside force or is violently jolted, whether it's a football tackle, a fall, a shaken baby, or a roadside bomb. Mild TBIs result in a concussion and a brief loss of consciousness, and severe TBIs can lead to comas and persistent vegetative states, although symptoms may not appear for months or years. Any type of TBI increases the risk of neurodegenerative diseases like Parkinson's and Lou Gherig's disease—which makes treating the initial injury even more important.
Researchers used to think that massive neuronal death caused TBIs, but Parker's biophysics background told him that this wasn't the case. Cell membranes, he said, are floppy "like the skin on a hound dog." The force of a blast couldn't destroy large numbers of neurons simply because the membranes could absorb much of that energy. What couldn't withstand that type of force was a type of protein in the cell membrane known as an integrin, which connect the inside of the cell with the outside environment.
Using neurons they grew in the lab, Parker and colleagues simulated the types of forces that would cause a TBI. In one experiment, they stretched the neurons rapidly, under great force, just as might happen when a soldier on patrol is hit with the massive wave of energy from an exploding roadside bomb. In another experiment, they simulated the molecular damage done by such a blast.Click here to view more
