Dysfunctional digestive tract highlights the metabolic hallmarks of nanoplastic-exacerbated Parkinson's pathology.

Parkinson's disease (PD) is increasingly viewed as both a neurological and metabolic disorder, with the gut-brain axis playing a key role. This study explored how polystyrene (PS) nanoplastics contributed to PD progression by examining their metabolic impact in an A53T α-synuclein (αS) mouse model. Mice given PS nanoplastics orally (2 mg/kg every other day for three months) displayed compromised gut barrier integrity, including a 30% drop in goblet cells and increased epithelial apoptosis in the ileum. Microbial diversity in the ileum rose sharply, with an overgrowth of Desulfovibrio spp. linked to neuroinflammation and αS aggregation. KEGG analysis confirmed apoptosis and lipopolysaccharide biosynthesis pathways influenced by nanoplastics, while metabolomics identified over 200 altered fecal metabolites, including those associated with cytochrome P450 activity and disruptions to cancer-related pathways. Additionally, histopathology revealed liver inflammation, underscoring the systemic effects of nanoplastic exposure. Overall, our findings suggest that environmental nanoplastics may aggravate PD physiopathology through gut-liver axis disruption and metabolic dysregulation.