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Inhalation of Nebulized Diesel Particulate Matter: A Safety Trial in Healthy Humans
No full textDiesel particulate matter (DPM) has adverse health effects. Examining the underlying pathophysiological mechanisms would be
facilitated by the introduction of an exposure method that is safe, portable, and cost-effective. The purpose of this study was to
establish a novel method to study DPM exposure via nebulization and an inhalation dose that was safe, yet capable of eliciting
an inflammatory response. Ten participants enrolled in this nonblinded, nonrandomized study. Subjects inhaled nebulized 0.9%
saline and increasing doses of DPM suspended in 0.9% saline (75, 150, and 300 g) in a sequential manner. FEV1 was measured
repeatedly during the first 2 h after exposure and blood, oximetry, sputum, and heart rate were taken before, 2 h, and 24 h after
inhalation challenge. DPM inhalation was well-tolerated at all doses. A decrease in FEV1 was observed after each inhalation
challenge (including saline). Inhalation of 300 g DPM produced a significantly different FEV1 response curve. An increase in
particle inclusion-positive sputum macrophages for all DPM doses confirmed that the nebulized particles were reaching the lower
airways. SerumGM-CSF was elevated after exposures to 150 and 300 gDPM.No other inflammatory changes were detected.DPM
inhalation via nebulizer is a safe method of delivering low doses of DPMs in healthy people
