Brain tocopherol levels are associated with lower activated microglia density in elderly human cortex.

Area of Science:

• Neuroscience
• Nutritional Psychiatry
• Gerontology

Background:

• Elevated brain tocopherol concentrations correlate with diminished Alzheimer's disease (AD) neuropathology.
• The precise mechanisms underlying this association remain largely undetermined.

Purpose of the Study:

• To investigate the relationship between brain levels of alpha-tocopherol and gamma-tocopherol and microglia density in individuals with and without Alzheimer's disease.
• To explore whether tocopherol-microglia associations are influenced by Alzheimer's disease neuropathology.

Main Methods:

• Analysis of brain tissue from 113 deceased participants in the Memory and Aging Project.
• Linear regression models examined associations between alpha- and gamma-tocopherol levels and microglia density.
• Models were adjusted for age, sex, education, APOE ε4 genotype, post-mortem interval, amyloid load, and neurofibrillary tangle severity.

Main Results:

• Higher cortical concentrations of alpha- and gamma-tocopherol were associated with lower total and activated microglia density.
• This association was not observed in subcortical brain regions.
• The link between cortical alpha-tocopherol and total microglia density remained significant even after accounting for AD neuropathology.

Conclusions:

• Tocopherols may influence Alzheimer's disease pathogenesis by modulating microglia activation.
• These findings suggest a potential neuroprotective role for tocopherols in Alzheimer's disease, mediated through their effects on the brain's immune cells.