On September 5, 2024, AURORA scientist Jeske van Boxel from Vrije Universiteit Amsterdam led the publication of a new study investigating the potential endocrine-disrupting effects of polystyrene (PS) micro- and nanoplastic (MNP) particles, a type of particle that has been previously found in human samples. Despite growing concerns over and research into endocrine disruption caused by plastic additives, the potential effects of micro- and nanoplastic particles themselves have not been extensively studied. The article examines the influence of various sizes and concentrations of PS-MNPs on estrogen (ER) and androgen (AR) receptor activity, as well as hormone production, using an in vitro model.
The study explores the uptake and biological effects of fluorescent PS-MNPs ranging in size from 50 to 10,000 nm and in concentrations from 0.01 to 100 µg/mL. The PS-MNPs were tested on three different human cell types: VM7, H295R, and AR-ecoscreen cells, which are commonly used to study endocrine activity and steroid hormone production.
Key findings include the observation that MNP uptake differs based on cell type. Particles of 1,000 nm or smaller were internalized by VM7 and H295R cells, while those 200 nm or smaller were taken up by AR-ecoscreen cells. H295R cells, which are involved in hormone production, showed the highest uptake of particles. For these cells, the PS-MNPs were located closer to the nucleus compared to other cell types.
However, none of the PS-MNP sizes or concentrations tested affected estrogen or androgen receptor activity. The study did find that exposure to PS-MNPs in H295R cells led to statistically significant changes in some hormone levels, although there was no consistent pattern based on particle size or concentration. Specifically, the PS-MNPs caused a reduction in the hormone estriol (E3), with a maximum decrease of 37.5% observed at the highest concentration of 100 µg/mL and a particle size of 50 nm. Additionally, the study noted an increase in the gene expression of oxidative stress markers, including GPX1 (1.26-fold) and SOD1 (1.23-fold).
Overall, the researchers concluded that PS-MNPs demonstrated limited endocrine-disrupting properties in vitro. However, given the role of estriol in pregnancy, the study highlighted the need for further research into the potential effects of micro- and nanoplastics on endocrine function, particularly during pregnancy.
This research adds to the growing body of work investigating the potential health impacts of micro- and nanoplastics, with a specific focus on hormone disruption and cellular response. Further studies are needed to fully understand any potential long-term implications of MNP exposure on human health.
Reference
Van Boxel, J., et al. (2024). “Effects of polystyrene micro- and nanoplastic on androgen- and estrogen receptor activity and steroidogenesis in vitro.” Toxicology In Vitro. DOI: 10.1016/j.tiv.2024.105938
