Consumer-derived polystyrene microplastics Alter redox homeostasis and epigenetic markers in primary human colonic epithelial cells

Abstract

Microplastics released from food-contact materials are an increasingly studied source of human gastrointestinal exposure. We investigated the effects of consumer-derived polystyrene microplastics (PS-MPs) generated from disposable coffee cup lids on primary human colonic epithelial (HCoEpiC) cells. After 24 h of exposure, increasing nominal mass concentrations of PS-MPs were associated with reduced cell viability; the IC50 was estimated to be >1,000 μg/mL under the tested conditions. Protein-normalized TBARS/MDA-equivalent levels showed a significant overall treatment effect (Kruskal–Wallis p = 0.0156), with a significant reduction at 800 μg/mL versus control after Bonferroni correction (adjusted p = 0.0067), rather than an increase. Intracellular reactive oxygen species (ROS) increased across the tested nominal mass concentrations and were accompanied by numerically higher total glutathione values, although the overall glutathione group effect was not statistically significant. Gene-specific DNA methylation analysis showed decreased methylation signals for DNMT1, DNMT3A, and DNMT3B, together with reduced global histone H3 acetylation. These findings indicate that acute PS-MP exposure was associated with measurable changes in redox-related and epigenetic endpoints in a primary human intestinal epithelial cell model. The study provides human cell-based evidence supporting further investigation into the long-term gastrointestinal implications of chronic exposure to plastic particles from food-contact materials.