Inhaled concentrated ambient particles are associated with hematologic andbronchoalveolar lavage changes in canines

Pulmonary inflammatory and hematologic responses of canines were studied af ter exposure to concentrated ambient particles (CAPs) using the Harvard amb ient particle concentrator (HAPC). For pulmonary inflammatory studies, norm al dogs were exposed in pairs to either CAPs or filtered air (paired studie s) for 6 hr/day on 3 consecutive days. For hematologic studies, dogs were e xposed for 6 hr/day for 3 consecutive days with one receiving CAPs while th e other was simultaneously exposed to filtered air; crossover of exposure t ook place the following week (crossover studies). Physicochemical character ization of CAPs exposure samples included measurements of particle mass, si ze distribution, and composition. No statistical differences in biologic re sponses were found when all CAPs and all sham exposures were compared. Howe ver, the variability in biologic response was considerably higher with CAPs exposure. Subsequent exploratory graphical analyses and mixed linear regre ssion analyses suggested associations between CAPs constituents and biologi c responses. Factor analysis was applied to the compositional data from pai red and crossover experiments to determine elements consistently associated with each other in CAPs samples. In paired experiments, four factors were identified; in crossover studies, a total of six factors were observed. Bro nchoalveolar lavage (BAL) and hematologic data were regressed on the factor scores. Increased BAL neutrophil percentage, total peripheral white blood cell (WBC) counts, circulating neutrophils, and circulating lymphocytes wer e associated with increases in the aluminum/silicon factor. Increased circu lating neutrophils and increased BAL macrophages were associated with the v anadium/nickel factor. Increased BAL neutrophils were associated with the b romine/lead factor when only the compositional data from the third day of C APs exposure were used. Significant decreases in red blood cell counts and hemoglobin levels were correlated with the sulfur factor. BAL or hematologi c parameters were not associated with increases in total CAPs mass concentr ation. These data suggest that CAPs inhalation is associated with subtle al terations in pulmonary and systemic cell profiles, and specific components of CAPs may be responsible for these biologic responses.