8-isoprostane in exhaled breath condensate after experimental exposure to wood smoke in humans

Wood smoke, a well-known indoor and outdoor air pollutant, may cause adverse health effects through oxidative stress. In this study 8-isoprostane, a biomarker of oxidative stress, was measured in exhaled breath condensate (EBC) and urine before and after experimental exposure to wood smoke. The results were compared with measurements of other biomarkers of oxidative stress and inflammation. Thirteen subjects were exposed first to clean air and then, after 1 week, to wood smoke in an exposure chamber during 4-hour sessions. Exhaled breath condensate, exhaled nitric oxide, blood and urine were sampled before and at various intervals after exposure to wood smoke and clean air. Exhaled breath condensate was examined for 8-isoprostane and malondialdehyde (MDA), while exhaled air was examined for nitric oxide, serum for Clara cell protein (CC16) and urine for 8-isoprostane. 8-isoprostane in EBC did not increase after wood smoke exposure and its net change immediately after exposure was inversely correlated with net changes in MDA (r(s)= -0.57, p= 0.041) and serum CC16 (S-CC16) (r(p)= -0.64, p= 0.020) immediately after the exposure. No correlation was found between 8-isoprostane in urine and 8-isoprostane in EBC. In this study controlled wood smoke exposure in healthy subjects did not increase 8-isoprostane in EBC.