# Detection of alpha-synuclein seeding activity in tear fluid in patients with Parkinson’s disease

## TL;DR

This study shows that tear fluid can be used to detect alpha-synuclein activity, a potential non-invasive biomarker for Parkinson’s disease.

## Contribution

The novel use of tear fluid with α-Syn seeding amplification assay provides a new non-invasive PD diagnostic approach.

## Key findings

- α-Syn seeding activity was detected in 67% of Parkinson’s disease tear fluid samples.
- Seeding-positive samples showed fibrillar structures consistent with α-Syn pathology.
- The assay effectively distinguished Parkinson’s disease from controls and prion diseases.

## Abstract

Detection of alpha-synuclein (α-Syn) seeding activity in tear fluid (TF) offers a promising non-invasive biomarker for Parkinson’s disease (PD). α-Syn seeding amplification assay (αSynSAA) detected seeding activity in 67% of PD-TF, while non-synucleinopathy samples remained negative. Electron microscopy of seeding-positive end products revealed fibrillar structures morphologically consistent with results of αSynSAA. αSynSAA effectively distinguished PD from controls and prion diseases based on seeding activity in TF.