| 1. |
- Bernick, Charles, et al.
(författare)
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Blood biomarkers and neurodegeneration in individuals exposed to repetitive head impacts.
- 2023
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Ingår i: Alzheimer's research & therapy. - 1758-9193. ; 15:1
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Tidskriftsartikel (refereegranskat)abstract
- It is unknown if fluid biomarkers reflective of brain pathologies are useful in detecting and following a neurodegenerative process in individuals exposed to repetitive head impacts. This study explores the relationship between blood biomarkers and longitudinal change in cognitive function and regional brain volumes in a cohort of professional fighters.Participants are drawn from a convenience sample of active and retired professional boxers and Mixed Martial Arts fighters and a control group with no prior exposure to head impacts. 3T MRI brain imaging, plasma samples, and computerized cognitive testing were obtained at baseline and, for a subset, annually. MRI regional volumes were extracted, along with plasma levels of neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), p-tau231, and N-terminal tau (NTA). Statistical analyses were performed to assess the relationship between plasma levels and regional brain volumes and cognitive performance at baseline and longitudinally.One hundred forty active boxers (mean age: 31 with standard deviation (SD) of 8), 211 active MMA (mean age of 30 with SD of 5), 69 retired boxers (mean age 49 with SD of 9), and 52 control participants (mean age 36 with SD of 12) were included in the analyses. Baseline GFAP levels were highest in the retired boxers (retired boxers v. active MMA: p=0.0191), whereas active boxers had higher levels of NfL (active boxers v. MMA: p=0.047). GFAP showed an increase longitudinally in retired boxers that was associated with decreasing volumes of multiple cortical and subcortical structures (e.g., hippocampus: B=-1.25, 95% CI,-1.65 to-0.85) and increase in lateral ventricle size (B=1.75, 95% CI, 1.46 to 2.04). Furthermore, performance on cognitive domains including memory, processing speed, psychomotor speed, and reaction time declined over time with increasing GFAP (e.g., processing speed: B=-0.04, 95% CI,-0.07 to-0.02; reaction time: B=0.52, 95% CI, 0.28 to 0.76). Among active fighters, increasing levels of GFAP were correlated with lower thalamic (B=-1.42, 95% CI,-2.34 to -0.49) and corpus callosum volumes, along with worsening scores on psychomotor speed (B=0.14, 95% CI, 0.01 to 0.27).Longitudinal plasma GFAP levels may have a role in identifying individuals exposed to repetitive head impacts who are at risk of showing progressive regional atrophy and cognitive decline.
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| 2. |
- Bernick, Charles, et al.
(författare)
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Longitudinal change in regional brain volumes with exposure to repetitive head impacts.
- 2020
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Ingår i: Neurology. - 1526-632X. ; 94:3
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Tidskriftsartikel (refereegranskat)abstract
- This study tests the hypothesis that certain MRI-based regional brain volumes will show reductions over time in a cohort exposed to repetitive head impacts (RHI).Participants were drawn from the Professional Fighters Brain Health Study, a longitudinal observational study of professional fighters and controls. Participants underwent annual 3T brain MRI, computerized cognitive testing, and blood sampling for determination of neurofilament light (NfL) and tau levels. Yearly change in regional brain volume was calculated for several predetermined cortical and subcortical brain volumes and the relationship with NfL and tau levels determined.A total of 204 participants who had at least 2 assessments were included in the analyses. Compared to controls, the active boxers had an average yearly rate of decline in volumes of the left thalamus (102.3 mm3/y [p = 0.0004], mid anterior corpus callosum (10.2 mm3/y [p = 0.018]), and central corpus callosum (16.5 mm3/y [p = <0.0001]). Retired boxers showed the most significant volumetric declines compared to controls in left (32.1 mm3/y [p = 0.002]) and right (30.6 mm3/y [p = 0.008]) amygdala and right hippocampus (33.5 mm3/y [p = 0.01]). Higher baseline NfL levels were associated with greater volumetric decline in left hippocampus and mid anterior corpus callosum.Volumetric loss in different brain regions may reflect different pathologic processes at different times among individuals exposed to RHI.
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| 3. |
- Bernick, Charles, et al.
(författare)
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Longitudinal performance of plasma neurofilament light and tau in professional fighters: The Professional Fighters Brain Health Study.
- 2018
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Ingår i: Journal of neurotrauma. - : Mary Ann Liebert Inc. - 1557-9042 .- 0897-7151. ; 35:20
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study is to evaluate longitudinal change in plasma neurofilament light (NF-L) and tau levels in relationship to clinical and radiological measures in professional fighters. Participants (active and retired professional fighters and control group) underwent annual blood sampling, 3 Tesla MRI brain imaging, computerized cognitive testing, and assessment of exposure to head trauma. Plasma tau and NF-L concentrations were measured using Simoa assays. Multiple linear regression models were used to compare the difference across groups in regard to baseline measurements, while mixed linear models was used for the longitudinal data with multiple measurements for each participant. Plasma samples were available on 471 participants. Baseline NF-L measures differed across groups (F_3,393=6.99, p=0.0001), with the active boxers having the highest levels. Higher NF-L levels at baseline were correlated with lower baseline MRI regional volumes and lower cognitive scores. The number of sparring rounds completed by the active fighters was correlated with NF-L (95% CI 0.0116-0.4053, p=0.0381), but not tau, levels. Among 126 subjects having multiple yearly samples, there was a significant difference in average yearly percentage change in tau across groups (F_3,83=3.87, p=0.0121).). We conclude that plasma NF-L and tau behave differently in a group of active and retired fighters; NF-L better reflects acute exposure whereas the role of plasma tau levels in signifying chronic change in brain structure over time requires further study.
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