Beta-amyloid deposition in chronic traumatic encephalopathy

Area of Science:

• Neuroscience
• Neuropathology
• Neurodegenerative Diseases

Background:

• Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease linked to repetitive mild traumatic brain injury.
• CTE is pathologically defined by abnormal tau accumulation, distinct from other tauopathies like Alzheimer's disease (AD).
• The role of amyloid-beta (Aβ) deposition in CTE progression and severity remains incompletely understood.

Purpose of the Study:

• To investigate the extent and characteristics of Aβ deposition in a cohort of deceased individuals with CTE.
• To determine if Aβ deposition is associated with more severe CTE pathology and adverse clinical outcomes.
• To compare Aβ deposition patterns in CTE with those in normal aging populations.

Main Methods:

• Studied a heterogeneous cohort of 114 deceased athletes and military veterans with neuropathologically diagnosed CTE.
• Assessed Aβ deposition, including diffuse and neuritic plaques, and its correlation with tauopathy stage, APOE ε4 allele, Lewy body disease, and dementia.
• Compared Aβ deposition rates and dynamics in CTE subjects to a normal aging cohort.

Main Results:

• Aβ deposition was present in 52% of CTE subjects, occurring at an accelerated rate and altered dynamics compared to normal aging.
• Aβ deposition was significantly associated with the APOE ε4 allele, older age at symptom onset, and older age at death.
• Neuritic plaques were linked to increased CTE tauopathy stage, co-morbid Lewy body disease, and dementia, independent of age.

Conclusions:

• Aβ deposition is altered and accelerated in a significant proportion of CTE cases.
• Aβ accumulation in CTE is associated with more severe neuropathology and worse clinical outcomes.
• These findings highlight a potential role for Aβ in the progression of CTE, distinct from or in conjunction with tau pathology.