Repetitive blast exposure in mice and combat veterans causes persistent cerebellar dysfunction

Area of Science:

• Neuroscience
• Neurology
• Traumatic Brain Injury Research

Background:

• Blast exposure is a known cause of mild traumatic brain injury (TBI).
• Understanding the neuropathology of repetitive blast exposure is crucial for both animal models and human veterans.
• The impact of cumulative blast exposures on neuroimaging findings in humans remains unclear.

Purpose of the Study:

• To investigate the dose-response relationship between the number of blast exposures and brain changes.
• To examine neuroimaging abnormalities in blast-exposed veterans and correlate them with the number of injuries.
• To compare neuropathological findings in mice with neuroimaging data from veterans.

Main Methods:

• Utilized (18)F-fluorodeoxyglucose (FDG) positron emission tomography to assess neuronal activity in veterans.
• Examined microlesions in the blood-brain barrier (BBB), Purkinje cell changes, and tau protein expression in mice.
• Performed diffusion tensor imaging (DTI) tractography on the cerebellum of blast-exposed veterans.

Main Results:

• A correlation was found between the number of blast exposures and FDG uptake in the veteran cerebellum.
• Blast exposure in mice led to BBB microlesions, Purkinje cell damage, and tau pathology, particularly in the ventral cerebellum.
• DTI revealed a negative correlation between mean diffusivity in the cerebellum and the number of blast-related mild TBIs in veterans.

Conclusions:

• The cerebellum is a vulnerable region to repetitive mild TBI from blast exposure in both animal models and humans.
• Early breakdown of blood-brain barrier integrity may contribute to long-term cerebellar changes following blast injury.
• Repetitive blast exposure shows a dose-dependent effect on cerebellar neuronal activity and white matter integrity.