There are growing concerns about potential delayed, neuropsychiatric consequences
(e.g, cognitive decline, mood or anxiety disorders) of sports-related traumatic brain
injury (TBI). Autopsy studies of brains from a limited number of former athletes have
described characteristic, pathologic changes of chronic traumatic encephalopathy (CTE)
leading to questions about the relationship between these pathologic and the neuropsychiatric
disturbances seen in former athletes. Research in this area will depend on in vivo
methods that characterize molecular changes in the brain, linking CTE and other sports-related
pathologies with delayed emergence of neuropsychiatric symptoms. In this pilot project
we studied former National Football League (NFL) players using new neuroimaging techniques
and clinical measures of cognitive functioning. We hypothesized that former NFL players
would show molecular and structural changes in medial temporal and parietal lobe structures
as well as specific cognitive deficits, namely those of verbal learning and memory.
We observed a significant increase in binding of [(11)C]DPA-713 to the translocator
protein (TSPO), a marker of brain injury and repair, in several brain regions, such
as the supramarginal gyrus and right amygdala, in 9 former NFL players compared to
9 age-matched, healthy controls. We also observed significant atrophy of the right
hippocampus. Finally, we report that these same former players had varied performance
on a test of verbal learning and memory, suggesting that these molecular and pathologic
changes may play a role in cognitive decline. These results suggest that localized
brain injury and repair, indicated by increased [(11)C]DPA-713 binding to TSPO, may
be linked to history of NFL play. [(11)C]DPA-713 PET is a promising new tool that
can be used in future study design to examine further the relationship between TSPO
expression in brain injury and repair, selective regional brain atrophy, and the potential
link to deficits in verbal learning and memory after NFL play.