Plastic particles can increase intestinal inflammation

A research team has investigated a possible link between the rising number of people with chronic inflammatory bowel disease and the increasing exposure to micro- and nanoplastics (MNPs). The research shows that plastic particles influence the immune cells and the intestinal microbiome and can thus increase inflammation. The results were recently published in the journal Microplastics and Nanoplastics.

The harmful effects of MNP were investigated in a mouse model with ulcerative colitis, one of the most common forms of chronic inflammatory bowel disease. The study focused on polystyrene particles of different sizes that were applied orally.

 Polystyrene is a widely used plastic that is frequently used for food packaging such as yogurt cups, meat trays or take-out boxes. The research team's extensive molecular and histological analyses provided evidence of interactions between MNP and intestinal inflammation.

The uptake of MNP by the intestinal mucosa was increased under inflammatory conditions. In addition, MNP exposure intensified the inflammatory immune response in the gut by triggering a pro-inflammatory activation of certain immune cells (macrophages). In addition, MNP exposure led to a disruption of the gut microbiome: the researchers observed a decrease in beneficial and an increase in pro-inflammatory and potentially harmful bacterial species.

Furthermore, this study shows that under inflammatory conditions, MNPs not only accumulate in the intestine but also in other excretory organs such as the liver and kidneys, as well as in the bloodstream.

This effect was observed particularly in the case of the very small nanoplastic particles, measuring less than 0.0003 millimeters, and indicates "that MNPs can cross biological barriers and have systemic effects far beyond the intestine, say the researchers.

Chronic inflammatory bowel diseases such as ulcerative colitis are on the rise, as is pollution from micro and nanoplastic particles. As the gastrointestinal tract is particularly exposed to increasing MNP exposure, the scientists focused on researching a possible correlation.

These results indicate that MNP is a previously underestimated factor in the development and intensification of chronic inflammatory bowel diseases.

Verena Kopatz et al, Polystyrene micro- and nanoplastics in a colitis mouse model – effects on biodistribution, macrophage polarization, and gut microbiome, Microplastics and Nanoplastics (2025). DOI: 10.1186/s43591-025-00160-7