Glutamate uptake by astrocytes has been postulated to play a neuroprotective role during brain inflammation. Using primary human fetal astrocyte cultures, we investigated the influence of selected cytokines on glutamate uptake activity. Interleukin (IL)-1β and tumor necrosis factor-α dose-dependently inhibited astrocyte glutamate uptake, whereas interferon (IFN)-γ alone stimulated this activity. The nitric oxide synthase inhibitor, NG-monomethyl-L-arginine, blocked IL-1β-mediated inhibition of glutamate uptake, suggesting involvement of nitric oxide in the effect of IL-1β. IL-1 receptor antagonist protein totally reversed the inhibitory effect of cytokines, suggesting a critical role of IL-1β. The anti-inflammatory cytokine IFN-β blocked cytokine (IL-1β plus IFN-γ)-induced inhibition of glutamate uptake with a corresponding reduction in nitric oxide generation. Taken together, these findings suggest that proinflammatory cytokines inhibit astrocyte glutamate uptake by a mechanism involving nitric oxide, and that IFN-β may exert a therapeutically beneficial effect by blocking cytokine-induced nitric oxide production in inflammatory diseases of the brain.
Environmental pollution with microplastics (MPs) is a major and worldwide concern. Involuntary exposure to MPs by ingestion or inhalation is unavoidable. The effects on human health are still under debate, while in animals, cellular MP translocation and subsequent deleterious effects were shown. First reports indicate a potential intrauterine exposure with MPs, yet readouts are prone to contamination. Method: To establish a thorough protocol for the detection of MPs in human placenta and fetal meconium in a real-life clinical setting, a pilot study was set up to screen for MPs > 50 µm in placental tissue and meconium sampled during two cesarean sections for breech deliveries. After chemical digestion of non-plastic material, Fourier-transform infrared (FTIR) microspectroscopy was used to analyze the presence of 10 common types of microplastic in placenta and stool samples. Results: Human placenta and meconium samples were screened positive for polyethylene, polypropylene, polystyrene, and polyurethane, of which only the latter one was also detected as airborne fallout in the operating room—thus representing potential contamination. Conclusion: We found MPs > 50 µm in placenta and meconium acquired from cesarean delivery. Critical evaluation of potential contamination sources is pivotal and may guide future clinical studies to improve the correct detection of MPs in organ tissue. Studies investigating nano-sized plastics in human tissue are warranted.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.