Clumps of amyloid-beta protein in the brain are a biomarker for neurodegenerative conditions, including Alzheimer’s disease. While the protein is not normally found in the brains of young people, previous studies have shown that amyloid plaques can occur within hours of a severe brain injury.
Understanding how traumatic injuries affect amyloid beta accumulation could aid the development of strategies to clear deposits of the protein in the brain, and delay or prevent neurodegeneration.
In the present study, researchers recruited nine military grenade or breacher instructors based in Missouri alongside nine civilians as a control group. Grenade and breacher instructors are military officers who train recruits to use hand grenades and explosives or other methods to force doors to open. Both groups were an average of 33 years old.
The instructors underwent PET scans at baseline- before exposure to explosions- and after exposure five months later. During the five-month interim period, they also filled out a digital log of the number of explosions experienced, including the firing of weapons. Control participants underwent PET scans at similar time points.
In the end, the researchers found that six of the nine military instructors had abnormal amyloid accumulation. While three participants had increased amyloid build-up in one area of the brain, two participants had increased amyloid in two regions, and one had increased accumulation in three regions. Meanwhile, none of the controls showed any abnormal amyloid accumulation.
The researchers noted that their findings might be limited as they only evaluated participants at a single time point after exposure to explosions. Evaluation at multiple time points would have been useful to observe how amyloid accumulation following traumatic injury evolves over time.
“Further research needs to be done to establish the relationship between the frequency and the severity of traumatic brain injury and the degree of amyloid changes in the brain, the natural course of the observed accumulation, and other potential biologic risk factors for amyloid plaque deposition and the development of cognitive decline,” said study author Carlos Leiva-Salinas, M.D., Ph.D., M.B.A., associate professor of radiology at the University of Missouri School of Medicine in Columbia, Missouri.
Sources: EurekAlert, Radiology
