Untoward Effects of Micro- and Nanoplastics: An Expert Review of Their Biological Impact and Epigenetic Effects.
Level 5 - mechanism / opinion, no new human data
Narrative expert review synthesizing preclinical and mechanistic evidence without original human data
PubMed 34928307 · doi:10.1093/advances/nmab154
What was done
The authors conducted an expert narrative review evaluating the biological impact, biodistribution, and epigenetic effects of microplastics (0.1 to 5000 µm) and nanoplastics (0.001 to 0.1 µm) following ingestion, focusing on intestinal and systemic pathways across preclinical models and potential risks to human health.
What was found
The abstract reports no quantitative numerical data or effect sizes. Qualitatively, ingestion of micro- and nanoplastics is associated with physical intestinal damage, increased intestinal permeability, reduced microbiota diversity, and localized inflammation. Preclinical models (marine organisms, *Caenorhabditis elegans*, and mice) show that nanoplastics dysregulate molecular signaling pathways and induce epigenetic alterations, although intestinal uptake appears low and size-dependent.
Why it matters
This review synthesizes the biological mechanisms through which dietary micro- and nanoplastics may disrupt gut integrity and cellular pathways, highlighting potential metabolic and transgenerational risks from chronic exposure.
Limits
The review relies primarily on non-mammalian and rodent model systems, with no direct human outcome data or clinical trial evidence presented. Quantitative uptake rates, dose-response relationships for low-dose human exposure, and specific clinical thresholds were not provided in the abstract.
Cited by
- supports Larger microplastics are poorly absorbed through gut epithelial cells and are excreted in feces, whereas smaller particles are more readily absorbed.