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THE EFFECT OF SIZE FRACTIONED PARTICULATE MATTER ON HUMAN AIRWAY EPITHELIAL CELLS IN VITRO
Citation:
Dailey, L. A., J M. Soukup, J Becker*, AND R B. Devlin. THE EFFECT OF SIZE FRACTIONED PARTICULATE MATTER ON HUMAN AIRWAY EPITHELIAL CELLS IN VITRO. Presented at Society of Toxicology Annual Meeting, Nashville, TN, March 17-22, 2002.
Description:
THE EFFECT OF SIZE FRACTIONATED PARTICULATE MATTER ON HUMAN AIRWAY EPITHELIAL CELLS IN VITRO. LA Dailey1, C Sioutas2, JM Soukup1, S Becker1, RB Devlin1. 1National Health & Environmental Effects Research Laboratory, USEPA, RTP, NC,USA; 2USC, Civil & Environmental Engineering, LA, CA..
Epidemiologic studies have demonstrated a compelling causal relationship between episodes of high concentrations of particulate matter (PM) and adverse health effects to the human respiratory and cardiovascular system, as evidenced by increased hospitalizations and mortality. Many factors have
been implicated in the toxicity of PM, including particle size, number and constituents. Advances in technology now allow researchers to simultaneously collect, concentrate, and size fractionate coarse, fine, and ultrafine ambient air particulates. We have collected ambient air PM in the following size ranges: coarse (CS) 2.5-10 micron, fine (FN) 0.1- 2.5 micron, and ultrafine (UF) <0.1 micron and examined their effects on human primary airway epithelial cells in vitro . Cells were exposed to 25, 100, and 250ug/ml doses of each PM fraction for 2 and 24 hours. LDH and the inflammatory cytokine IL-8were measured. Preliminary studies show that all three fractions elicit a dose dependent response at 24 hours. When airway epithelial cells were exposed to different PM fractions on an equal mass basis, CS and UF fractions appeared to induce a larger cytokine response than FN particles. At 250ug/ml, the highest dose examined, cells exposed to CS PM had approximately 4.3 fold greater IL-8 production than untreated cells; cells exposed to UF had 3.7 fold increased IL-8, while cells exposed to FN PM had 2.5 fold increased IL-8 compared to untreated cells. Similarly, human alveolar macrophages exposed 18 hours to 10ug/ml CS and FN PM showed a far greater IL-6 cytokine production in response to coarse PM than fine PM (81.2 vs 7.8 fold increases compared to control). These studies do not provide compelling evidence that ultrafine particles are more toxic that larger particles. [This is an abstract of a proposed presentation & does not necessarily reflect EPA policy.]