Non-invasive analysis of peripheral biomarkers for early diagnosis of alpha-synucleinopathies

Objectives Clinical diagnosis of Parkinson’s disease (PD), multiple system atrophy (MSA) and dementia with Lewy bodies (DLB) is challenging, particularly in the early stages, due to the presence of overlapping symptoms. The goal of this study is to establish a panel of biomarkers for PD, MSA, and DLB using innovative and non-invasive methods. Specifically, we aim to explore the peripheral distribution of disease-associated alpha-synuclein and investigate novel molecules implicated in these neurodegenerative diseases. Methods Patients with PD, MSA, DLB, other neurodegenerative diseases (OND), and healthy subjects (HS) underwent olfactory mucosa (OM), urine and blood sampling. A combination of assays was performed: ultrasensitive Single Molecule Array (SIMOA) to detect neurofilament light chain (NfL), phosphorylated tau (p-Tau-181, p-Tau-231), ELISA to evaluate alpha-synuclein and synapsin-3 levels, and Nanoparticle Tracking Analysis (NTA) to characterize extracellular vesicles (EVs) in urine and blood. Results Our preliminary results revealed by SIMOA a significant increase in plasma levels of NfL in MSA patients compared to PD and HS, while no significant differences were found in p-Tau-181 and p-Tau-231 levels. Plasma alpha-synuclein levels were similar across all groups, instead in PD and MSA urine samples have shown a trend to increase than other groups. The characterization of b-EVs by NTA has revealed an increase of the concentration (particles/mL) and ratio (conc/size) in neurodegenerative groups compared with HS. The other analyses are still ongoing. Conclusions Our preliminary findings highlight the potential of OM, blood and urine as rich sources of biomarkers that can be easily and periodically collected. These biomarkers may significantly contribute to the clinical understanding and diagnosis of PD, MSA, and DLB, offering a promising direction for non-invasive diagnostic strategies in neurodegenerative diseases.