Genotoxic and immunomodulatory effects in human white blood cells after ex vivo exposure to polystyrene nanoplastics

Plastic and its derivatives micro- and nanoplastics (MNPLs) accumulation is a substantial environmental and ecological problem that could potentially become a serious health concern to humans. In this study, we propose an attractive approach to get new data, using polystyrene nanoparticles (PSNPs) as a model, to understand the risk of MNPLs human exposure. Whole blood samples from different donors were exposed ex vivo to different concentrations of PSNPs for 24, 48, or 72 h. The effects were analyzed in different subsets of white peripheral blood cells (WBCs), namely lymphocytes, monocytes, and polymorphonuclear (PMN) cells, to assess specific cellular sensitivity. Our results showed no significant toxicity of PSNPs when evaluated on the overall WBCs population. Nevertheless, different lineages manifested sharp differences between cell types with very limited uptake in lymphocytes, very high uptake in monocytes, and with intermediate uptake values for PMN cells. Furthermore, a significant increase in the levels of DNA damage was observed in monocytes and PMN cells after PSNPs exposure, but not in lymphocytes. Interestingly, our results showed that PSNPs exposure-induced changes in the whole blood secretome. These findings were further confirmed when the expression of different cytokines was analyzed, revealing a significant increase in the expression of different cytokines related to the inflammatory, immune, and stress response, as well as cell proliferation.