The importance of airborne bacterial endotoxins in an urban environment

Although not visible by the naked eye, the air is teeming with bacteria. Inevitably, these airborne bacteria are frequent visitors of the respiratory system. Endotoxins are highly inflammatory lipid components of Gram-negative bacteria. In an urban environment, they may act by heightening immune responses in the presence of other pollutants, such as particulate matter (PM). However, our knowledge on the involvement of airborne endotoxins in PM-related inflammation is restricted on the methods used for its collection, quantification and analysis. Until now, collection methods have relied on filter-based samplers which are far from ideal for the recovery of endotoxins. For this reason, our study focusses on developing a new, more efficient, non-filter based strategy for the monitoring of endotoxins in an urban environment. Our first experiments could detect much higher ambient endotoxin concentrations than the available data in the literature for urban studies. This re-sparks the debate of the importance of endotoxins in the health effects of PM. Therefore, detailed studies will be done in cell models to investigate the contribution of endotoxins in PM-associated inflammation in relevant concentrations and in comparison with other pollutants. Finally, responses to natural PM exposure will be analysed in vivo at RNA level in nasal brushing samples and compared with the responses observed in the cell models.

Keywords:ENDOTOXIN

Disciplines:Microbiology, Systems biology, Laboratory medicine