Microplastics have been detected to be present in the human placenta (FPF reported and here) but their impact on placental cells is largely unknown. Fanglin Shen and co-authors from Fudan University, Shanghai, China, and The University of Queensland, Brisbane, Australia were interested in exploring this new field by focusing on polystyrene. In their article published on August 7, 2022, in the journal Water Research, they compare the mechanistic toxicity of differently charged polystyrene nanoplastics (PS-NPs) on placental cells.
For their experiments, the authors used four sizes of PS-NPs (25, 50, 100, and 500 nm) which were NH2-labeled (PS-NH2), COOH-labeled (PS-COOH), or unlabeled. They exposed human placental choriocarcinoma (JEG-3) cells to several nanoplastics concentrations between 20 and 500 mg/mL for 24 hours and assessed cytotoxicity, intracellular reactive oxygen species (ROS) level, protein kinase A (PKA) activity, the cell cycle, and mRNA expression of specific genes.
The researchers found that the toxicity increased with decreasing particle size. Moreover, “NH2-labeled PS-NPs caused greater effects on cytotoxicity, inhibition of protein kinase A (PKA) activity, oxidative stress, and cell cycle arrest compared to COOH-labeled and unmodified PS-NPs” of the same size. Accordingly, Shen et al. concluded that PS-NP toxicity depends on their size and surface charge. Furthermore, nanoparticles resulted in increased ROS levels which were hypothesized to be the factor responsible for the other observed toxic effects (cytotoxicity, cell cycle arrest, PKA activity inhibition).
According to the authors, their results demonstrate that nanoplastics negatively affect human placental cells. They recommend “to conduct risk assessment of nanoplastics on female reproduction and fetal development” and to perform chronic exposure studies with environmentally relevant plastic particle concentrations. The EU is already undertaking research in this area. Five Horizon 2020 research projects are now working to better understand micro- and nanoplastic impacts on human health (FPF reported). One of the projects (AURORA) is specifically focusing on the assessment of microplastics’ effects on the placenta and the developing fetus.
Reference
Shen, F. et al. (2022). “Mechanistic toxicity assessment of differently sized and charged polystyrene nanoparticles based on human placental cells.” Water Research. DOI: 10.1016/j.watres.2022.118960
