Blast-related concussions linked to higher Alzheimer's risk

 U.S. veterans of the wars in Afghanistan and Iraq who suffered mild traumatic brain injury from exposure to explosive blasts were found to have changes in cerebrospinal fluid proteins that are typically seen in people who develop Alzheimer's disease, according to researchers at the University of Washington School of Medicine and VA Puget Sound Health Care System.

"While our research does not prove that veterans who experienced these injuries will develop Alzheimer's disease, it raises the possibility that they may be on a pathway leading to dementia," said Dr. Ge Li, the paper's first author and an associate professor of psychiatry and behavioral sciences at UW Medicine.

The study was published March 13 in the journal Neurology.

Previous research has found that sustaining a moderate to severe TBI increases a person's risk of developing Alzheimer's disease. It is not known, however, whether a mild TBI (mTBI) similarly increases this risk.

In the new study, the researchers analyzed protein levels in spinal fluid from 51 U.S. veterans of the wars in Afghanistan and Iraq. Each had suffered mTBIs from exposure to explosive blasts and had an average of 20 blast injuries. Those protein levels were compared with the protein levels of 85 veterans and civilians of similar age who had never sustained a TBI.

In this study, the veterans were considered to have experienced a TBI if they had an alteration or loss of consciousness from the blast. The TBIs were considered mild if the loss of consciousness lasted 30 minutes or less and there was no sign of brain damage on standard clinical MRI or CT scan. Such an injury is considered equivalent to a concussion.

The researchers examined protein levels in the veterans' cerebrospinal fluid, which flows around and through the brain and carries away waste materials. Two of the proteins measured compose the chief components of amyloid plaques, which aggregate in the brains of people with Alzheimer's. These proteins are called alpha-beta amyloid 40 and 42 (Aβ40, Aβ42).

The other proteins are versions of the tau protein. Normally, tau proteins are part of cells' cytoskeletons, which give cells their shape. But with Alzheimer's, these structures are changed, creating tangles within brain cells and killing them. This is the other hallmark of Alzheimer's.

Source: ScienceDaily