EPA Science Inventory

Correlative Ultratructural Investigations of Airway Epithelium Following Experimental Exposure to Defined Air Pollutants and Lifestyle Exposure to Tobacco Smoke

Citation:

Carson, J., L. Brighton, A. Collier, AND P. Bromberg. Correlative Ultratructural Investigations of Airway Epithelium Following Experimental Exposure to Defined Air Pollutants and Lifestyle Exposure to Tobacco Smoke. INHALATION TOXICOLOGY. Taylor & Francis, Inc., Philadelphia, PA, 25(3):134-40, (2013).

Description:

Context: Investigations of cell/molecular level effects of in vivo exposure of airway mucosa of experimental animals to common irritant gases have demonstrated structural and physiological changes reflective of breaches in epithelial barrier function, presence of inflammatory cell infiltrate, and compromised ciliary function. These experimental animal studies provided useful perspectives of plausible, but more subtle pathologic outcomes having relevance to lifestyle exposure to gaseous environmental irritants including tobacco smoke. Methods: Freeze-fracture technology was applied to ultrastructural examination of large airway epithelium, with appropriate controls, from guinea pigs exposed to ozone, and of nasal mucosa of human subjects exposed to ozone or sulfur dioxide, and nasal mucosa of active smokers. Results: We documented substantive membrane structural changes to tight junctional complexes and cilia as well as an infiltrate of neutrophils into the surface mucosal layer in exposed animals. These patterns also were evident but not as pervasive among human subjects acutely exposed experimentally to irritant gases and those chronically exposed by their lifestyle to tobacco smoke. Discussion: Our intent was to characterize respiratory tract mucosal membrane disorganization associated with high level acute irritant exposures in an experimental animal model and to evaluate evidence of similar but perhaps more subtle pathologic change associated with lower level experimental or lifestyle exposures. Our studies demonstrate continuity, albeit subtle, of pathologic change from high dosage experimental animal exposure to low dosage human exposures.

Purpose/Objective:

Context: Investigations of cell/molecular level effects of in vivo exposure of airway mucosa of experimental animals to common irritant gases have demonstrated structural and physiological changes reflective of breaches in epithelial barrier function, presence of inflammatory cell infiltrate, and compromised ciliary function. These experimental animal studies provided useful perspectives of plausible, but more subtle pathologic outcomes having relevance to lifestyle exposure to gaseous environmental irritants including tobacco smoke. Methods: Freeze-fracture technology was applied to ultrastructural examination of large airway epithelium, with appropriate controls, from guinea pigs exposed to ozone, and of nasal mucosa of human subjects exposed to ozone or sulfur dioxide, and nasal mucosa of active smokers. Results: We documented substantive membrane structural changes to tight junctional complexes and cilia as well as an infiltrate of neutrophils into the surface mucosal layer in exposed animals. These patterns also were evident but not as pervasive among human subjects acutely exposed experimentally to irritant gases and those chronically exposed by their lifestyle to tobacco smoke. Discussion: Our intent was to characterize respiratory tract mucosal membrane disorganization associated with high level acute irritant exposures in an experimental animal model and to evaluate evidence of similar but perhaps more subtle pathologic change associated with lower level experimental or lifestyle exposures. Our studies demonstrate continuity, albeit subtle, of pathologic change from high dosage experimental animal exposure to low dosage human exposures.

URLs/Downloads:

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 05/08/2014
Completion Date: 05/08/2014
Record Last Revised: 07/28/2014
Record Created: 05/08/2014
Record Released: 05/08/2014
OMB Category: Other
Record ID: 275273

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB

ENVIRONMENTAL PUBLIC HEALTH DIVISION