Short-term exposure to particulate matter induces arterial but not venous thrombosis in healthy mice

Abstract

Background:- Epidemiological findings suggest an association between exposure to particulate matter (PM) and venous thrombo-embolism. Objectives:- To investigate arterial vs. venous thrombosis, inflammation and coagulation in mice, (sub)acutely exposed to two types of PM. Methods:- Various doses (25, 100 and 200-μg per animal) of urban particulate matter (UPM) or diesel exhaust particles (DEP) were intratracheally (i.t.) instilled in C57Bl6/n mice and several endpoints measured at 4, 10 and 24-h. Mice were also repeatedly exposed to 100-μg per animal on three consecutive days with endpoints measured 24-h after the last instillation. Results:- Exposure to 200-μg per mouse UPM enhanced arterial thrombosis, but neither UPM nor DEP significantly enhanced venous thrombosis. Both types of PM induced dose-dependent increases in broncho-alveolar lavage fluid (BALF) total cell numbers (mainly neutrophils) and cytokines (IL-6, KC, MCP-1, RANTES, MIP-1α), with peaks at 4-h and overall higher values for UPM than for DEP. Systemic inflammation was limited to increased serum IL-6 levels, 4-h after UPM. Both types of PM induced similar and dose-dependent but modest increases in factor (F)VII, FVIII and fibrinogen. Three repeated instillations did not or only modestly enhance the proinflammatory and procoagulant status. Conclusions:- Compared with DEP, UPM induced more pronounced pulmonary inflammation, but both particle types triggered similar and mild short-term systemic effects. Hence, acute exposure to PM triggers activation of primary hemostasis in the mouse, but no substantial secondary hemostasis activation, resulting in arterial but not venous thrombogenicity. © 2010 International Society on Thrombosis and Haemostasis.