Elevated blood microplastics and their potential association with Parkinson's disease.

Microplastic (MP) contamination in human blood and its potential link to Parkinson's disease (PD) remain poorly understood. In this study, we collected whole blood samples from 21 PD patients and 12 age- and sex-matched healthy controls under strict anticontamination protocols. A lifestyle questionnaire was administered to assess MP exposure-related habits, revealing that PD patients reported more frequent use of disposable plastic products and bottled water consumption, suggesting greater environmental exposure. Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS), laser direct infrared imaging (LDIR) and scanning electron microscopy (SEM) were used to quantify and characterize the MPs. Five polymer types-polyethylene (PE), polystyrene (PS), polyvinyl chloride (PVC), polypropylene (PP) and nylon-66 (PA66)-were detected in the sample. The total MP burden was significantly greater in PD patients than in controls (21.36 ± 8.42 vs. 13.56 ± 5.92 μg/g; p < 0.01), with the greatest increases observed for PVC (1.49-fold), PP (2.74-fold) and PA66 (6.62-fold), whereas the PE and PS levels were not significantly different. LDIR and SEM analyses revealed diverse particle morphologies, with most polymers appearing as granular particles. In vitro assays further revealed that PVC and PP microplastics induced dopaminergic neuron apoptosis and increased the level of phosphorylated α-synuclein (p-α-syn), providing support for their potential neurotoxicity. Together, these findings indicate elevated blood MP levels in PD patients and offer preliminary evidence linking polymer exposure with PD-related neuronal vulnerability.