27 Acute and Chronic Effects on Inflammatory Markers by Quartz and Particle Exposure in the Iron Foundry Environment

Abstract Inflammation is a central mechanism in the aetiology of particulate matter (PM)-associated diseases, including cardiovascular diseases (CVD). Both acute inflammatory events and chronic low-grade inflammation due to exposure contribute to adverse health effects of exposure. The aim of the current study was to determine if current exposure levels to respirable quartz or dust at Swedish iron foundries induce acute or chronic systemic inflammatory responses, using biomarkers broadly classified into three groups; 1) general markers of inflammation, 2) novel inflammatory markers of CVD, and 3) NLRP3 inflammasome-related markers. Exposure to respirable dust and quartz was determined during a workday in 40 iron foundry workers, and blood samples were collected before and after workshift. The sampling procedure was repeated approximately three weeks later. To determine acute effects of exposure, the over-shift difference in biomarker levels were studied, whereas to study chronic effects, the average morning sample biomarker levels were correlated to the average exposure levels of the two sampling occasions. We found that biomarkers of the NLRP3 inflammasome correlated to quartz exposure, including acute and chronic effects on ex vivo caspase-1 activation in monocytes, acute effects on plasma levels of IL-18, and chronic effects on IL-1Ra plasma levels. Our results suggest that the present exposure levels to respirable quartz in the Swedish iron foundries, which were below the Swedish occupational limits, may trigger inflammasome activation in the exposed workers.