Background and Objectives: Fine particulate matter, PM_2.5, is becoming a major threat to human health, particularly in terms of respiratory diseases. Pyroptosis is a recently discovered and distinct form of cell death, characterized by pore formation in the cell membrane and secretions of proinflammatory cytokines. There has been little research on the effect of PM_2.5 on pyroptosis, especially in airway epithelium. We investigated whether PM_2.5-related oxidative stress induces pyroptosis in bronchial epithelial cells and defined the underlying mechanisms. Materials and Methods: After exposure of a BEAS-2B cell line to PM_2.5 concentration of 20 µg/mL, reactive oxygen species (ROS) levels, parameters related to pyroptosis, and NF-κB signaling were measured by Western blotting, immunofluorescence, and ELISA (Enzyme-linked immunosorbent assay). Results: PM_2.5 induced pyroptotic cell death, accompanied by LDH (Lactate dehydrogenase) release and increased uptake of propidium iodide in a dose-dependent manner. PM_2.5 activated the NLRP3-casp1-gasdermin D pathway, with resulting secretions of the proinflammatory cytokines IL-1β and IL-18. The pyroptosis activated by PM_2.5 was alleviated significantly by NLRP3 inhibitor. In PM_2.5-exposed BEAS-2B cells, levels of intracellular ROS and NF-κB p65 increased. ROS scavenger inhibited the expression of the NLRP3 inflammasome, and the NF-κB inhibitor attenuated pyroptotic cell death triggered by PM_2.5 exposure, indicating that the ROS/NF-κB pathway is involved in PM_2.5-induced pyroptosis. Conclusions: These findings show that PM_2.5 exposure can cause cell injury by NLRP3-inflammasome-mediated pyroptosis by upregulating the ROS/NF-κB pathway in airway epithelium.

An exhalation delivery system for fluticasone (EDS-FLU) is designed to deposit drug into sinonasal regions above the inferior turbinate, particularly sinus drainage pathways not reached by standard nasal steroid sprays. We evaluated the efficacy and safety of EDS-FLU for chronic rhinosinusitis (CRS). We reviewed four independent randomized controlled trials derived from three published articles identified through searches of PubMed, Embase, SCOPUS, Google Scholar, Web of Science, and the Cochrane Library up to April 2024. Outcomes included 22-item Sinonasal Outcome Test (SNOT-22) scores, nasal symptom scores, nasal polyp scores, patient global impression of change (PGIC), responder and surgical indication rates, and adverse events. Compared with EDS-placebo, EDS-FLU produced greater reductions in nasal polyp scores and SNOT-22 scores over 6 months. At 3 months, nasal congestion, facial pain, rhinorrhea, and olfactory dysfunction improved more with EDS-FLU, and PGIC responder and complete response rates were higher at 3 and 6 months. EDS-FLU reduced surgical indication and increased overall responder rates at 3 months but not at 6 months. Epistaxis and nasal septal erosion or ulceration occurred more frequently with EDS-FLU, whereas rates of headache, nasal congestion, nasopharyngitis, and upper respiratory infection were similar between groups. EDS-FLU provides clinically meaningful improvements in subjective and objective outcomes in CRS but is associated with an increased risk of local nasal adverse events, warranting individualized risk-benefit assessment.