Association of cognitive function with amyloid-β and tau proteins in the vitreous humor

Background: The eye may serve as source for diagnostic testing for early detection of Alzheimer's disease (AD). Examination of amyloid-β (A-β) and tau protein content in human vitreous and its correlation to neuro-cognition may improve ocular-based AD detection methods. Objective: To evaluate levels of A-β and tau protein in human vitreous humor and investigate the clinical predictive role of these proteins as early diagnostic markers of AD. Methods: A prospective, single-center, multi-surgeon cohort study. Vitreous humor samples from 80 eyes were measured quantitatively for A-β_40-42, pTau, and tTau. Linear regression was used to test associations between AD biomarker levels, Mini-Mental State Exam (MMSE), and serum apolipoprotein E (APOE) allele status, with adjustment for age, sex, and education level of patients. Results: LowerMMSEscores were significantly associated with lower levels of vitreous A-β ₄₀ (p = 0.015), A-β ₄₂ (p = 0.0066), and tTau (p = 0.0085), and these biomarkers were not associated with any pre-existing eye conditions. Presence of the-β4 allele and the-β2 allele approached significance with reduced A-β ₄₀ level (p = 0.053) and increased p-Tau level (p = 0.056), respectively.