Transcript Slide 1
Exposure to agriculture dust particles during allergen sensitization exacerbates allergic airway inflammation Alex Castañeda, M.S. Graduate Group in Immunology University of California Davis Dr. Kent Pinkerton Director, Center for Health & the Environment Department of Pediatrics, School of Medicine Professor of Anatomy, Physiology and Cell Biology UC Davis School of Veterinary Medicine Asthma Allergen Environmental/Occupational Factors Ovalbumin Ambient Particles Genetic Factors Kim et al. 2010. The many pathways to asthma. Nature Immunology 11: 577-584 Allergic Asthma Symptoms: Airway inflammation, bronchial constriction, coughing, wheezing, and shortness of breath Prevalence: 235 million people worldwide (11 million in the US) In California (San Joaquin Valley) 25% of all children are diagnosed with allergic asthma Particle Pollution Studies have shown a correlation between asthma and high particulate matter exposure -Particular matter exacerbate asthma -The use of source specific ambient particles has not been studied Particulate Matter: Vehicle emissions (gasoline) Agricultural Dusts Diesel exhaust gases Mineral dusts Hydrocarbons Particles Size: Coarse particles Fine Particles Ultrafine particles (0.1µm in diameter) Location: Fresno California (Leading agriculture-producing county in the nation) Particles collected during summer nights (2010) Agricultural Dust Generation Field preparation for crops, fertilization, crop harvest (ex- almonds) Composition Inorganic (Mineral Dusts) Silcates (aluminum silicates), quartz, transition metals Organic (Carbonates) Toxicity of Inorganic Agricultural Dusts Cellular toxicity Generate free radicals Oxidative cellular stress Activation of the immune system towards an inflammatory state -Fibrogenesis Hypothesis Exposure to agricultural dust particles during sensitization with an allergen (house dust mites or ovalbumin) will exacerbate airway inflammation in BALB/c mice Methods Murine Model- BALB/c mice Treatments Allergen- OVA, Purified OVA or Purified House Dust Mites (HDM) Agricultural Dust- Ultrafine Particles (Fresno) Sensitization (days 1, 3, & 5) OVA & pOVA- 10ug intranasal HDM- 25ug intranasal Challenge (days 12, 13, & 14) OVA & pOVA- 10ug aerosolized HDM- 10 ug OVA Groups 1 -Control (No Allergen + Filtered Air) 2- OVA + Filtered Air 3- OVA + Particulate Matter 4- pOVA + Filtered Air 5- pOVA + Particulate Matter 6- pHDM + Filtered Air 7- pHDM + Particulate Matter Tissue Collection Blood Plasma (IgE,IgG1) BALF Lung (Homogenize & Fixed) Allergen Sensitization+ Ambient Particles 0 Allergen Challenge 5 10 15 Necropsy BALF Cellular Proflies Total Cells Neutrophils Macrophages Eosinophils Results- Tissue Histology Control Allergen and particulate matter Alcian Blue Periodic Acid Schiff’s Stain Mucosubstance Results- Tissue Histology P M D Airway Inflammation: Volume of Intraepithelial Mucosubstances Area of Basal Lamina ( µm3 µm2 ) Results- Tissue Histology P M D Results- Total Protein Results- Antibody Production Results- IL-17-A Production Barnes et al. 2008. Immunology of asthma and COPD.Nature Reviews Immunology 8, 183-192 Results- IL-17-E Production Summary Airway inflammation was exacerbated when particulate matter was introduced during allergen sensitization (HDM only, not OVA) -Significantly elevated levels of total cells, macrophages, and neutrophils Based on muco-substance production HDMA causes significantly more airway inflammation over Ova IL-17A production was elevated in the HDMA model, correlating with increased neutrophils, however there is no correlation to particles Future Work Investigate the mechanisms through which agricultural dust enhances airway inflammation -How particles activate the immune system? Investigate neutrophil infiltration -Do particles increase neutrophilic inflammation? Acknowledgements Pinkerton Laboratory Kent Pinkerton, Ph.D. Chris Carosino Dale Uyeminami Janice Peake Katherine Johnson Imelda Espiritu Alexa Pham Esther Shin Jocelyn Claude All other members UC Davis Western Center for Agricultural Health and Safety Marc Schenker, M.D. Sandra Freeland All other members Graduate Group in Immunology