Circulating polymer-resolved microplastics in pediatric epilepsy: higher internal burden in drug-resistant cases.

Drug-resistant epilepsy (DRE) in children remains a major clinical challenge, and environmental contributors to pharmacoresistance are not fully understood. In this study, we quantified polymer-resolved microplastics (MPs) in peripheral blood from pediatric patients with controlled epilepsy (CE), drug-resistant epilepsy (RE), and healthy controls (NC) using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) with laser direct infrared (LDIR) validation. Eight polymer types were detected. Total circulating polymer-resolved MP burden was observed to be higher in epilepsy patients, with the highest levels in the RE subgroup. Specific polymers, including polystyrene (PS), polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), were enriched in RE. Self-reported exposure variables did not fully explain these group differences. In a small MRI-negative subgroup, exploratory whole-exome sequencing identified descriptive differences in selected variant categories between controlled and drug-resistant epilepsy patients; however, these findings were not used to infer microplastic uptake, retention, transport, biotransformation, or clearance. Given the small sample size, limited exposure reconstruction, and cross-sectional design, all findings should be interpreted as preliminary and hypothesis-generating. Larger longitudinal studies with standardized contamination control, quantitative exposure assessment, and independent validation cohorts are needed to confirm these observations.