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How Combat Explosions Injure the Brain


Combat veterans from the wars in Iraq and Afghanistan who were surveyed say they experienced an average of 21 blasts from improvised explosive devices (IEDs) during the course of their military service. While the explosions rarely kill soldiers, they still render considerable harm. A new study published in Science Translational Medicine finds that the brain becomes damaged in a number of ways.

The cerebellum, a part of the brain that regulates motor control and cognition, is particularly susceptible to blast injury. A closer look at the brains of both veterans and experimental models reveals microscopic changes that could potentially cause deleterious long-term effects. "We find that there are many multi-factorial abnormalities in the cerebellum, including injury to the blood brain barrier, inflammation, and structural damage to cells," says co-authors Satoshi Minoshima, MD, PhD, chair of radiology at the University of Utah, and Donna Cross, PhD, soon to be a faculty member at the University of Utah. They developed advanced imaging technologies that were central to many of the findings.

The blood brain barrier (BBB) is a layer of tissue that prevents infectious bacteria and other abnormal substances from entering the brain. After blasts the BBB becomes leaky, damaging nearby brain cells, which could drive long-term changes in the brain. The injuries worsen with repeated blasts.

The brains also build up tau, a protein seen in patients with dementia and Alzheimer's disease. "The results could mean that brain trauma puts individuals at risk for neurodegenerative diseases by possibly sharing common pathologic pathways," says Minoshima.

These and other findings spotlight a need for strategies to prevent brain damage that could lead to neurodegenerative diseases. Drs. Cross and Minoshima are actively working on such therapeutic developments. More research will need to be done to determine how the brain injuries cause common long-term symptoms such as memory loss and loss of coordination.