Posters

Detection of amyloid-beta and tau biomarkers in tear fluid of patients with Alzheimer’s disease

Poster Details

First Author: M.Gijs THE NETHERLANDS

Co Author(s):    I. Ramakers   F. Verhey   R. Nuijts   C. Webers           

Abstract Details

Purpose:

To investigate the level of amyloid-beta and tau biomarkers in tear fluid of patients with cognitive impairment and healthy controls.

Setting:

University Eye Clinic Maastricht & Memory Clinic of the Alzheimer Center Limburg, Maastricht University Medical Center (MUMC+), Maastricht, the The Netherlands.

Methods:

Tear fluid was collected from 60 patients and nine cognitively healthy controls (HC) using Schirmer strips. Patients were grouped according to their clinical diagnosis. Twenty-five (42%) patients received a diagnosis of subjective cognitive disorder (SCD), 23 (38%) patients had a diagnosis of mild cognitive impairment (MCI) and 9 (15%) patients were diagnosed with dementia. Levels of amyloid-beta peptides (AB38, AB40, AB42), total-tau and p-tau were determined using multiplex electrochemiluminescence immunoassays (Meso Scale Discovery).

Results:

The HC group displayed a significant higher tear migration length than in the patients groups (p = 0.001). No differences in the total protein content across diagnostics groups were observed (p = 0.225). Although amyloid-beta peptides (AB38, AB40, AB42) were detectable in tear fluid, their levels were similar between diagnostic groups. Significant differences in tear total-tau were observed between HC and dementia (p = 0.035) and between HC and MCI (p = 0.008). Interestingly, tear p-tau was not detectable in HC samples. We found moderately negative correlations between CSF AB42 and tear AB42 and between CSF AB42 and tear total-tau.

Conclusions:

To best of our knowledge, this study shows for the first time presence of amyloid-beta peptides (AB38, AB40, AB42), total tau and p-tau in tear fluid of patients with cognitive decline and healthy controls. Particularly tear total-tau showed promising results as it could distinguish between patients and controls. Tear fluid might help in finding non-invasive alternatives to CSF that could serve as front-line diagnostics for AD.

Financial Disclosure:

None