Abstract
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor and non-motor symptoms, including cognitive decline and reduced quality of life. Identifying reliable biomarkers for disease progression and symptom severity remains a critical challenge. In this study, levels of oxidative stress-related microRNAs (miR-24-3p, miR-103a-3p, miR-320a-3p, miR-494-3p, miR-126-5p, and miR-543) within blood serum extracellular vesicles (EVs) were examined in a cohort of 93 PD patients to assess their associations with cognitive function, symptom severity, quality of life, and other clinical characteristics. The methods included microRNA extraction from blood serum EVs, followed by cDNA synthesis and RT-qPCR for expression analysis. Upregulation of miR-126-5p, as well as downregulation of miR-24-3p showed the strongest associations with symptom severity and cognitive decline, whereas downregulated miR-320a-3p levels correlated with patient-reported quality of life in PD patients. Downregulation of miR-103a-3p, and miR-543 expression showed slight associations with motor symptoms, cognitive function, and quality of life domains; however, some of these associations lacked statistical power. These findings indicate that specific microRNA expression profiles in extracellular vesicles are associated with PD symptom severity and progression, supporting their further evaluation as biomarkers in larger independent cohorts.