Polystyrene microplastics induce biochemical and metabolism changes in human placental explants

The escalating presence of microplastics (MP) in the environment is a growing concern globally, with potential implications for human health as seen by their presence in various human tissues, including the placenta. Although there is extensive knowledge about the environmental effects of MPs, their impact on the health of the placenta and fetal development is not well understood. Key questions about their ability to cross the placental barrier, their cytotoxicity, and their influence on placental physiology remain unanswered. This study investigates whether MPs can be internalized by the placental tissue, their cytotoxicity, and the primary biochemical and metabolic effects. Term placental chorionic villi explants were exposed to 100 μg/mL of 4 μm polystyrene microplastics (PS-MP) for up to 72 hours in vitro. The integration of PS-MP by placental explants was assessed using Confocal Atomic Force Microscopy (AFM). Cytotoxic effects were measured using lactate dehydrogenase (LDH) release assay. The biochemical response was determined through levels of antioxidant enzymes and reactive oxygen species, while the metabolic impact was studied using nuclear magnetic resonance (NMR). The results showed that exposure to PS-MP led to significant cytotoxicity (p ¡ 0.01) and induced oxidative stress, as demonstrated by decreased antioxidant enzyme activity and increased markers of oxidative damage. Metabolic analysis revealed significant alterations suggesting mitochondrial dysfunction and disturbances in folate, and amino acid pathways, with disruptions in the tricarboxylic acid (TCA) cycle. Confocal AFM results confirmed the ability of PS-MP to surpass the placental barrier of placental explants. Overall, the findings highlight the severe cytotoxic, oxidative, and metabolic effects of PS-MP on placental explants, posing serious concerns about their adverse impacts on placental health and pregnancy outcomes. Financial support: Brazilian National Council for Scientific and Technological Development (CNPq) and the Alagoas Research Foundation (FAPEAL). Also see: https://micro2024.sciencesconf.org/557699/document