[Skip to Content]
[Skip to Content Landing]
Views 8,314
Citations 0
Original Investigation
January 2017

Imaging of Glial Cell Activation and White Matter Integrity in Brains of Active and Recently Retired National Football League Players

Author Affiliations
  • 1Department of Psychiatry and Behavioral Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland
  • 2Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins Medical Institutions, Baltimore, Maryland
  • 3Department of Neurology, Johns Hopkins Medical Institutions, Baltimore, Maryland
  • 4Concussion Legacy Foundation, Waltham, Massachusetts
  • 5Alzheimer’s Disease and CTE Center, Boston University School of Medicine, Boston, Massachusetts
  • 6School of Chemistry, University of Sydney, New South Wales, Australia
  • 7Discipline of Medical Radiation Sciences, University of Sydney, Sydney, New South Wales, Australia
  • 8Department of Biostatistics, Johns Hopkins Medical Institutions, Baltimore, Maryland
  • 9Department of Environmental and Occupational Health, Florida International University, Miami
  • 10Program in Cognitive Neuroscience and Imaging, Florida International University, Miami
JAMA Neurol. 2017;74(1):67-74. doi:10.1001/jamaneurol.2016.3764
Key Points

Question  Is localized brain injury, indicated by higher translocator protein signal and white matter changes, linked to National Football League (NFL) play?

Findings  In this cross-sectional, case-control study of young NFL players compared with control participants, players showed higher translocator protein positron emission tomographic signal in 8 of 12 regions examined. Limited significant white matter changes were also observed in NFL players compared with control participants, although players and control participants did not differ in regional brain volumes or neuropsychological performance.

Meaning  These results suggest that localized brain injury may be associated with NFL play, although further study is needed to test links to onset of neuropsychiatric symptoms.

Abstract

Importance  Microglia, the resident immune cells of the central nervous system, play an important role in the brain’s response to injury and neurodegenerative processes. It has been proposed that prolonged microglial activation occurs after single and repeated traumatic brain injury, possibly through sports-related concussive and subconcussive injuries. Limited in vivo brain imaging studies months to years after individuals experience a single moderate to severe traumatic brain injury suggest widespread persistent microglial activation, but there has been little study of persistent glial cell activity in brains of athletes with sports-related traumatic brain injury.

Objective  To measure translocator protein 18 kDa (TSPO), a marker of activated glial cell response, in a cohort of National Football League (NFL) players and control participants, and to report measures of white matter integrity.

Design, Setting, and Participants  This cross-sectional, case-control study included young active (n = 4) or former (n = 10) NFL players recruited from across the United States, and 16 age-, sex-, highest educational level–, and body mass index–matched control participants. This study was conducted at an academic research institution in Baltimore, Maryland, from January 29, 2015, to February 18, 2016.

Main Outcomes and Measures  Positron emission tomography–based regional measures of TSPO using [11C]DPA-713, diffusion tensor imaging measures of regional white matter integrity, regional volumes on structural magnetic resonance imaging, and neuropsychological performance.

Results  The mean (SD) ages of the 14 NFL participants and 16 control participants were 31.3 (6.1) years and 27.6 (4.9) years, respectively. Players reported a mean (SD) of 7.0 (6.4) years (range, 1-21 years) since the last self-reported concussion. Using [11C]DPA-713 positron emission tomographic data from 12 active or former NFL players and 11 matched control participants, the NFL players showed higher total distribution volume in 8 of the 12 brain regions examined (P < .004). We also observed limited change in white matter fractional anisotropy and mean diffusivity in 13 players compared with 15 control participants. In contrast, these young players did not differ from control participants in regional brain volumes or in neuropsychological performance.

Conclusions and Relevance  The results suggest that localized brain injury and repair, indicated by higher TSPO signal and white matter changes, may be associated with NFL play. Further study is needed to confirm these findings and to determine whether TSPO signal and white matter changes in young NFL athletes are related to later onset of neuropsychiatric symptoms.

×