Urban Particulate Matter Induces Changes in Gene Expression in Vascular Endothelial Cells that Are Associated with Altered Clot Structure In Vitro

Background  Particulate matter contained in ambient air pollution has been associated with cardiovascular diseases in several epidemiological studies. Objective  The aim of this study was to investigate the potential for urban particulate matter to induce changes in clot structure through interaction with vascular endothelial cells. Methods  We examined the structure of clots formed on human umbilical vascular endothelial cells that had been treated with various types of particles versus those formed on untreated cells. Particles used were standard reference particulate matter from diesel engine emissions (SRM2975) and urban ambient collection (SRM2787). Results  There was a dose-dependent increase in fibre density in clots formed on particle-treated endothelial cells. It was also found that exposure to the particles induced increased expression of tissue factor and reduced expression of thrombomodulin genes as measured by real-time polymerase chain reaction and increased expression of von Willebrand factor and plasminogen activation inhibitor-1 as measured by ELISA. Conclusion  These changes are consistent with increased procoagulant activity of air pollution particulate matter–treated endothelial cells and suggest that particulate matter has the potential to promote clot formation through changes induced in endothelial genes controlling clot formation.