Researchers with the Department of Veterans Affairs (VA) and the Center for the Study of Traumatic Encephalopathy (CSTE) at Boston University School of Medicine have provided the first pathological evidence of a link between repeated head injuries—such as those experienced by athletes in contact sports such as boxing, football, and hockey—and a disease (chronic traumatic Encephalomyopathy) that resembles amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease. The results will appear in the September issue of the Journal of Neuropathology and Experimental Neurology.
“We can't treat what we don't understand”
"This initial research shows great promise for further understanding what people go through after a traumatic brain injury, whether sustained on the battlefield, during a contact sport, or from other injury," said Secretary of Veterans Affairs Eric Shinseki. "Advancing our knowledge in this area is the key to better treatment outcomes."
The brain has long kept scientists baffled, as its elaborate structure makes it uniquely difficult to study. Brain biopsies are too risky as general practice, and diagnostic images often fall short of providing the desired details for full understanding of brain function. So, neurology researchers rely heavily on brain banks, including some housed at the Bedford (Mass.) VA Medical Center, for collecting clues about the biological nature of brain-related medical conditions.
For the new study, Dr. Ann McKee and colleagues at the CSTE examined the brains and spinal cords of 12 athletes donated by family members to the CSTE Brain Bank at the Bedford VA Medical Center.
The researchers found that all 12 athletes showed evidence of chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease caused by repetitive trauma to the brain. The condition can result in large accumulations of tau proteins, killing cells in regions of the brain responsible for mood and emotions.
In addition to CTE, three of the athletes had been afflicted by motor neuron disease, with severe and progressive muscle weakness and deterioration for several years before their death. The brains from patients with CTE and motor neuron disease showed a unique pattern of tau and deposits of another protein, TDP-43, in the spinal cord and brain. The pattern was different from that found in the most common form of ALS.
Previous epidemiological studies have suggested a possible link between repetitive head trauma experienced by athletes and combat veterans and the development of motor neuron diseases such as ALS.
"This is the first pathological evidence that repetitive head trauma might be associated with the development of an ALS-like disease," said McKee. "Although much more work is necessary to completely understand this association, if repetitive head trauma can trigger this kind of neurodegeneration, then by studying the effects of repetitive mild brain trauma, we can learn about the early triggers of ALS and how to slow, reduce and reverse them.
"Future work based on these observations offers a significant opportunity to develop treatments to benefit Veterans and all Americans well into the future," McKee said.
McKee and her colleagues are also studying whether military troops with traumatic brain injury from blasts or other exposures on the battlefield experience the same types of effects.
"We can't treat what we don't understand," says McKee. "The idea with these brain banks is to learn as much as possible about brain diseases, including their origins and any environmental or genetic triggers."
McKee is director of neuropathology at the Bedford (Mass.) VA Medical Center, where this research was conducted. She is also director of the Bedford-based VA brain banks, and CSTE co-director, as well as an associate professor of neuropathology and neurology at Boston University School of Medicine.
ALS affects about 30,000 people in the United States. It is relentlessly progressive and is nearly always fatal. The disease causes degeneration of nerve cells in the brain and spinal cord that leads to muscle weakness, muscle atrophy, and spontaneous muscle activity. The cause of ALS is unknown and there is no effective treatment.
In 2008, VA established ALS as a presumptive compensable illness for all Veterans with 90 days or more of continuously active service in the military.
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