Investigation of vascular inflammation induced by ceria particles synthesized by hydrogen fueled spray flame

Diesel particulate filters (DPF) have become essential as diesel regulations have become more stringent. Ceria particles suspended in fuel have been used as a catalyst to lower the regeneration temperature of DPF for light duty vehicles. However, there have been concerns about possible adverse health effects of ceria by inhalation in the case of DPF failure. Although there have been some studies of the possible adverse health effects of ceria particles, much remains to be determined. In this study, we probed the impact of ceria particles on vascular endothelial cell inflammation. Ceria particles were synthesized using a hydrogen fueled spray flame. SMPS, XRD and BET results confirmed that 35-40 nm CeO₂ particles with 3-7 nm crystalline size were synthesized. Human aortic endothelial cells (HAECs) were incubated for 4 hours with the CeO₂ particles at concentrations ranging from 0.001 to 50 μg/ml. Quantitative real time PCR was used to establish mRNA levels of three inflammatory makers. At the highest particle concentration tested (50 μg/ml), incubation of HAECs with CeO₂ particles produced modest (1.4- to 2-fold) mRNA up-regulation for all three inflammatory markers. Our results suggest that acute exposure to CeO₂ particles may elicit a modest level of vascular endothelial cell inflammation.