Real-world outdoor air exposure effects in a model of the human airway epithelium - A comparison of healthy and asthmatic individuals using a mobile laboratory setting

We developed a mobile laboratory allowing field exposure of lung tissue models to ambient air at localities with various pollution sources (Background, Industrial, Traffic, Urban) in different seasons (summer/fall/winter). In samples originating from healthy and asthmatic individuals, we assessed the parameters of toxicity, lipid peroxidation and immune response; we further performed comprehensive monitoring of air pollutants at sampling sites. We measured lactate dehydrogenase (LDH) and adenylate kinase (AK) production and transepithelial electrical resistance (TEER), analyzed 15-F2t-isopostane (IsoP) and a panel of 20 cytokines/chemokines/growth factors. In the ambient air, we detected particulate matter (PM), and other relevant chemicals (benzene, benzo[a]pyrene (BaP), NOx). In the Traffic locality, we found very high concentrations of ultrafine particles and NOx and observed low TEER values in the exposed samples, indicating significant traffic-related toxicity of the ambient air. In the Urban locality, sampled in winter, we observed high PM and BaP levels. We found lower AK levels in samples from healthy individuals exposed in this locality than in the asthmatic samples. In the samples from the Industrial locality, sampled in summer, we detected higher concentrations of TNFα, MIP-1α, Eotaxin, GROα, GM-CSF, IL-6 and IL-7 than in the Urban locality samples. We hypothesize that pollen or other plant-related components of the ambient air were responsible for this response. In conclusion, our data proved the feasibility of our mobile laboratory for field measurements of the biological response of lung tissue models exposed to ambient air, reflecting not only the levels of toxic compounds, but also season-specific parameters.

Portable emissions toxicity system: Evaluating the toxicity of emissions or polluted air by exposure of cell cultures at air-liquid interface in a compact field-deployable setup

Exposure of cell cultures at air-liquid interface (ALI), mimicking i.e. human lung surface, is believed to be one of the most realistic means to model toxicity of complex mixtures of pollutants on human health. The complexity of the close cooperation of "emissions source" and toxicology groups and of the instrumentation are among the limiting factors of ALI. In this work, the concepts of ALI exposure and real-world emissions monitoring using portable emissions monitoring systems (PEMS) are combined into a portable emissions or air toxicity system, for field deployment, including operation in moving vehicles. Cell cultures grown on 6 mm inserts are placed in an airtight 17x13x9 cm exposure box, where the sample is symmetrically distributed into 8 wells of a standard Transwell 24-well holder at 25 cm3/min/insert. In a 40x35x45 cm inner dimensions incubator, sample and control air are conditioned to 5 % CO2, 37 °C and >85 % humidity and drawn through 2-4 exposure boxes. Characterization with silver nanoparticles revealed 50 % particle losses at 15 nm and deposition rate of approximately 1.5 % at both 10 and 21 nm mean diameter. The system has undergone an extensive field validation, including 4 h of exposure and 2 h transport in a vehicle each day for 5 days, 5-day operation outside in vans and tents at -7 to +32 °C, long transport and test on a heavy-duty truck, during which cells were exposed to the diluted exhaust from the truck, this being the first known use of ALI exposure chamber as PEMS. The portable exposure chamber, along with a field-deployable auxiliary mobile base including a small laminar flow box, additional incubator and freezer, can be easily used to study the toxicity of various emissions, effluents and polluted air, aiming for a more relevant toxicity measure than chemical composition alone.