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Divergent effects of urban particulate air pollution on allergic airway responses in experimental asthma: a comparison of field exposure studies.
Environ Health. 2012 Jul 06; 11:45.EH

Abstract

BACKGROUND

Increases in ambient particulate matter of aerodynamic diameter of 2.5 μm (PM2.5) are associated with asthma morbidity and mortality. The overall objective of this study was to test the hypothesis that PM2.5 derived from two distinct urban U.S. communities would induce variable responses to aggravate airway symptoms during experimental asthma.

METHODS

We used a mobile laboratory to conduct community-based inhalation exposures to laboratory rats with ovalbumin-induced allergic airways disease. In Grand Rapids exposures were conducted within 60 m of a major roadway, whereas the Detroit was located in an industrial area more than 400 m from roadways. Immediately after nasal allergen challenge, Brown Norway rats were exposed by whole body inhalation to either concentrated air particles (CAPs) or filtered air for 8 h (7:00 AM - 3:00 PM). Both ambient and concentrated PM2.5 was assessed for mass, size fractionation, and major component analyses, and trace element content. Sixteen hours after exposures, bronchoalveolar lavage fluid (BALF) and lung lobes were collected and evaluated for airway inflammatory and mucus responses.

RESULTS

Similar CAPs mass concentrations were generated in Detroit (542 μg/m3) and Grand Rapids (519 μg/m3). Exposure to CAPs at either site had no effects in lungs of non-allergic rats. In contrast, asthmatic rats had 200% increases in airway mucus and had more BALF neutrophils (250% increase), eosinophils (90%), and total protein (300%) compared to controls. Exposure to Detroit CAPs enhanced all allergic inflammatory endpoints by 30-100%, whereas inhalation of Grand Rapids CAPs suppressed all allergic responses by 50%. Detroit CAPs were characterized by high sulfate, smaller sized particles and were derived from local combustion sources. Conversely Grand Rapids CAPs were derived primarily from motor vehicle sources.

CONCLUSIONS

Despite inhalation exposure to the same mass concentration of urban PM2.5, disparate health effects can be elicited in the airways of sensitive populations such as asthmatics. Modulation of airway inflammatory and immune responses is therefore dependent on specific chemical components and size distributions of urban PM2.5. Our results suggest that air quality standards based on particle speciation and sources may be more relevant than particle mass to protect human health from PM exposure.

Authors+Show Affiliations

Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA. wagnerja@msu.eduNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22768850

Citation

Wagner, James G., et al. "Divergent Effects of Urban Particulate Air Pollution On Allergic Airway Responses in Experimental Asthma: a Comparison of Field Exposure Studies." Environmental Health : a Global Access Science Source, vol. 11, 2012, p. 45.
Wagner JG, Morishita M, Keeler GJ, et al. Divergent effects of urban particulate air pollution on allergic airway responses in experimental asthma: a comparison of field exposure studies. Environ Health. 2012;11:45.
Wagner, J. G., Morishita, M., Keeler, G. J., & Harkema, J. R. (2012). Divergent effects of urban particulate air pollution on allergic airway responses in experimental asthma: a comparison of field exposure studies. Environmental Health : a Global Access Science Source, 11, 45. https://doi.org/10.1186/1476-069X-11-45
Wagner JG, et al. Divergent Effects of Urban Particulate Air Pollution On Allergic Airway Responses in Experimental Asthma: a Comparison of Field Exposure Studies. Environ Health. 2012 Jul 6;11:45. PubMed PMID: 22768850.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Divergent effects of urban particulate air pollution on allergic airway responses in experimental asthma: a comparison of field exposure studies. AU - Wagner,James G, AU - Morishita,Masako, AU - Keeler,Gerald J, AU - Harkema,Jack R, Y1 - 2012/07/06/ PY - 2012/02/13/received PY - 2012/06/12/accepted PY - 2012/7/10/entrez PY - 2012/7/10/pubmed PY - 2012/12/29/medline SP - 45 EP - 45 JF - Environmental health : a global access science source JO - Environ Health VL - 11 N2 - UNLABELLED: BACKGROUND: Increases in ambient particulate matter of aerodynamic diameter of 2.5 μm (PM2.5) are associated with asthma morbidity and mortality. The overall objective of this study was to test the hypothesis that PM2.5 derived from two distinct urban U.S. communities would induce variable responses to aggravate airway symptoms during experimental asthma. METHODS: We used a mobile laboratory to conduct community-based inhalation exposures to laboratory rats with ovalbumin-induced allergic airways disease. In Grand Rapids exposures were conducted within 60 m of a major roadway, whereas the Detroit was located in an industrial area more than 400 m from roadways. Immediately after nasal allergen challenge, Brown Norway rats were exposed by whole body inhalation to either concentrated air particles (CAPs) or filtered air for 8 h (7:00 AM - 3:00 PM). Both ambient and concentrated PM2.5 was assessed for mass, size fractionation, and major component analyses, and trace element content. Sixteen hours after exposures, bronchoalveolar lavage fluid (BALF) and lung lobes were collected and evaluated for airway inflammatory and mucus responses. RESULTS: Similar CAPs mass concentrations were generated in Detroit (542 μg/m3) and Grand Rapids (519 μg/m3). Exposure to CAPs at either site had no effects in lungs of non-allergic rats. In contrast, asthmatic rats had 200% increases in airway mucus and had more BALF neutrophils (250% increase), eosinophils (90%), and total protein (300%) compared to controls. Exposure to Detroit CAPs enhanced all allergic inflammatory endpoints by 30-100%, whereas inhalation of Grand Rapids CAPs suppressed all allergic responses by 50%. Detroit CAPs were characterized by high sulfate, smaller sized particles and were derived from local combustion sources. Conversely Grand Rapids CAPs were derived primarily from motor vehicle sources. CONCLUSIONS: Despite inhalation exposure to the same mass concentration of urban PM2.5, disparate health effects can be elicited in the airways of sensitive populations such as asthmatics. Modulation of airway inflammatory and immune responses is therefore dependent on specific chemical components and size distributions of urban PM2.5. Our results suggest that air quality standards based on particle speciation and sources may be more relevant than particle mass to protect human health from PM exposure. SN - 1476-069X UR - https://www.unboundmedicine.com/medline/citation/22768850/Divergent_effects_of_urban_particulate_air_pollution_on_allergic_airway_responses_in_experimental_asthma:_a_comparison_of_field_exposure_studies_ L2 - https://ehjournal.biomedcentral.com/articles/10.1186/1476-069X-11-45 DB - PRIME DP - Unbound Medicine ER -