Short-term effects of urban air pollution on human airway epithelium

Abstract

Background: Atmospheric particulate matter (PM) constitutes the major threat for modern societies and poses adverse effects on the respiratory system. Major contributors to PM content are combustion-related sources. Winter heating-related pollution is particularly important in Eastern Europe, where emissions from biofuel combustion are high and poorly regulated. The Aim: To clarify acute effects of the extract of actual urban fine PM with high benzo[a]pyrene (BaP) content collected in Eastern European mid-sized city during winter heating season on human airway epithelium. Methods: Human airway epithelial cells (line BEAS-2B) were exposed to fine PM extract. Cell viability and proliferation, cell layer integrity, levels of apoptosis and oxidative stress were monitored. In addition, pro-inflammatory cytokine expression was assessed. Cells’ ability to participate in wound healing in vitro was also documented. Results: BaP concentration in fine PM (3.08 ng/m³) used for our study is significantly higher than the limit value (1 ng/m³) set by European Commission. Stable carbon isotope ratio and radiocarbon analysis reveals that fine PM extract constituents originate mainly from heating systems. Fine PM extract induces decrease in bronchial cell viability, alters cell layer integrity, increases apoptosis and oxidative stress during the 3-day exposure. Also, pro-inflammatory cytokine expression was upregulated at gene and protein levels. Conclusions: Urban fine PM with high level of BaP significantly impacts respiratory health. Exposure to fine PM paves the road to the incoming infectious insults, inflammation and tissue loss leading to the exacerbation of COPD and/or similar diseases.