Contributing to the Mechanistic Understanding of Asthma Development: Allergenic and Inflammatory Cell Response from Exposure to Salton Sea Derived Aerosol

RYAN W. DROVER, Trevor Biddle, Mia R. Maltz, Qi Li, Daniel Gonzalez, David D. Lo, David R. Cocker III, University of California, Riverside

     Abstract Number: 504
     Working Group: Aerosol Exposure

Abstract
The Salton Sea is a rapidly drying endorheic body of water in California’s Riverside and Imperial counties. This retreat of the water level has led to continuously increasing exposure of playa, a significant source of PM10 as dust in the area. In the aqueous environment, the drying and addition of toxins has resulted in increasing salinity, algal blooms, and overall toxicity, contributing to the die-off of fish and migratory birds. Alongside these environmental issues, a public health crisis has developed in communities that experience one of the highest asthma rates in California (20-22.4%. vs. 14.5% California statewide) and are among the highest rates of hospitalization for asthma in the state.

The dual 540 L whole-body animal (mouse) exposure chambers have been used to measure pulmonary responses distinct from allergic inflammation from Salton Sea-sourced aerosol, with comparative exposure studies conducted using aerosolized Pacific Ocean water and fungal allergen (Alternaria). This work includes 48-hour and 7-day mouse exposures conducted with aerosol produced from Salton Sea playa and seasonally-collected dust from passive dust collectors, as well as lipoteichoic acid (LTA) from Staphylococcus aureus and lipopolysaccharide (LPS) from Escherichia coli. The exposure target concentrations were determined based on levels that promoted inflammatory cell recruitment without an accompany cytokine storm (1, 15, and 150 ug/m3 for LTA and LPS, 750 ug/m3 for Alternaria, and 1500 ug/m3 for Salton Sea environmental samples). Differential responses were measured for allergic and immune response, including neutrophil and eosinophil recruitment and gene expression changes. Salton Sea material from different sources were found to produce different responses in exposed mice, contributing to our mechanistic understanding of the particular asthma developed in the region.