Does enhancement of oxidative stress markers mediate health effects of ambient air particles?

Evidence indicates that oxidative stress generation may contribute to health effects associated with particulate matter (PM) exposure. We investigated oxidative stress markers in 113 workers exposed to metal-rich PM and 61 non-exposed comparable volunteers. The plasma levels of soluble NOX2-derived peptide (sNOX2-dp) and two oxidative stress markers, urinary 8-hydroxydeoxyguanosine (8OH-dG) and 8-iso-prostaglandinF2alpha (8-iso-PGF2), were analysed. The plasma levels of the antioxidant alpha-tocopherol were also evaluated. The workers' average exposure to PM with aerodynamic diameter <10 μm (PM10) was much higher at the workplace than in the city where the volunteers lived. Workers had significantly higher urinary 8-iso-PGF2 and 8-OHdG and plasma sNOX2-dp levels than non-exposed subjects. Alpha-tocopherol was much lower in workers compared to non-exposed subjects. In multivariable regression models adjusted for age, body mass index and smoking, 8-iso-PGF2α increased in workers in association with PM10 and metal exposure; 8-OHdG and sNOX2-dp were associated only with iron. Alpha-tocopherol was inversely associated with each of the oxidative stress markers. Our observation leads to the hypothesis that the enhancement of oxidative stress markers associated with exposure to high metal-rich PM levels represents a possible step in the pathways leading from particle exposure to systemic (e.g., cardiovascular) effects.