AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Toxicological Assessment of Emerging Diesel Fuel Emissions: The EMITTED Study
JOSEPHINE COOPER, Krystal J. Godri, Naomi Zimmerman, Terry Jung, Cheol-Heon Jeong, Greg J. Evans, James S. Wallace, SOCAAR, University of Toronto
Abstract Number: 667 Working Group: Health Related Aerosols
Abstract Vehicle emissions contribute significantly to urban ambient particulate matter, and exposure to these emissions has been associated with adverse cardio-respiratory effects. As light-duty diesel vehicle use across North America increases, and new emission treatment technologies and diesel fuel types are introduced, there is a growing need for toxicologically relevant measures of diesel exhaust characteristics.
One aim of the EMITTED (Exhaust Measurement and Inhalation Toxicology Testing of Emerging Diesel fuels) study is the development of a realistic in vitro model to explore airway exposure to diesel exhaust particulates (DEP). Biomarkers representative of the airway’s immunological response were used to elucidate toxicologically relevant responses to DEP.
An in vitro model of the airway was constructed using the Calu-3 human bronchial epithelial cell line in an air-liquid mono-culture. The model was exposed to liquid solutions of suspended iron dust and carbon black (positive and negative control, respectively), or liquid impinged and filter extracted DEP solutions of <200nm in diameter. DEP was generated by a heavy-duty diesel engine, which was fitted with a diesel oxidation catalyst and particulate filter. The engine was operated under 25% and 75% full loads with diesel fuel types: soy, animal fat, and commercially available ultra-low sulphur diesel.
Changes in extracellular and intracellular concentrations of the cytokines: GM-CSF, IFN-gamma, IL-1alpha, IL-1beta, IL-6, IL-8, and VEGF were quantified by ‘multiplexing’ using Millipore’s Luminex instrument. As DEP effects have been attributed to its oxidative properties, DCFH oxidation by reactive oxygen species in the cell was measured in parallel. To ensure the model was viable throughout DEP exposures, cell cytotoxicity was also assessed through resazurin reduction.
DEP exposure induced the airway’s protection, adaptation and inflammation responses through elevation of reactive oxygen species and immunomodulatory protein concentrations. Further investigation of these pathway activations should reveal the mechanisms by which DEP exposure causes airway toxicity.