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SEASONAL EFFECTS OF ULTRAFINE, FINE, AND COARSE PARTICULATE MATTER (PM) ON HUMAN PRIMARY AIRWAY EPITHELIAL CELLS
Citation:
Dailey, L. A. AND R B. Devlin. SEASONAL EFFECTS OF ULTRAFINE, FINE, AND COARSE PARTICULATE MATTER (PM) ON HUMAN PRIMARY AIRWAY EPITHELIAL CELLS. Presented at Society of Toxiocology 42nd Annual Meeting, Salt Lake City, UT, March 9-13, 2003.
Description:
SEASONAL EFFECTS OF ULTRAFINE, FINE, AND COARSE PARTICULATE MATTER (PM) ON HUMAN PRIMARY AIRWAY EPITHELIAL CELLS
Exposure of humans to PM results in increased mortality and morbidity. Recent toxicology studies have shown a number of pathophysiological pulmonary and cardiovascular changes following exposure to fine PM. However, the relative potency of ultrafine, fine, and coarse PM has not yet been characterized, nor is it well understood if PM emitted at different seasons of the year has different potencies. We have been collecting ultrafine, fine, and coarse ambient PM in Chapel Hill for the past year using the ChemVol High Volume Cascade Impactor developed by the Harvard School of Public Health. Samples were pooled into monthly batches to allow us to examine seasonal differences in PM effects on human airway epithelial cells. The fractions tested included coarse (2.5-10 microns), fine (0.1-2.5 microns), and ultrafine (<0.1micron). This abstract presents results from PM collected in October 2001 and April 2002. Human primary airway cells were exposed to equal masses (0, 25, 50, 100, and 250 ug/ml) of each PM fraction for 2 and 24hrs. Changes in expression of IL8, COX2 and heme oxygenase-1(HHOX1) genes were assessed at each time point. Exposure to October fine and ultrafine PM resulted in 5x and 9x greater increases in HHOX1 expression, respectively, compared with the corresponding April fractions; coarse PM from either month had a minimal effect on HHOX1 expression. In contrast, exposure to coarse PM collected in both October and April resulted in a 10 fold increase in COX2 expression while fine and ultrafine PM stimulated minimal expression of COX2. Increases in IL8 paralleled those seen for COX2. Detailed chemical analysis of each fraction will allow us to determine if the differential responses we have seen are associated with specific components present in each fraction. These data will provide useful information to the EPA on health effects associated with specific size fractions of PM. [This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.]