Exhaled breath condensate biomarkers in asbestos-related lung disorders

Summary

Objectives

Asbestos induces generation of reactive oxygen and nitrogen species in laboratory studies. Several such species can be measured non-invasively in humans in exhaled breath condensate (EBC) but few have been evaluated. This study aimed to assess oxidative stress and lung inflammation in vivo.

Methods

Eighty six men were studied: sixty subjects with asbestos-related disorders (asbestosis: 18, diffuse pleural thickening (DPT): 16, pleural plaques (PPs): 26) and twenty six age- and gender-matched normal individuals.

Results

Subjects with asbestosis had raised EBC markers of oxidative stress compared with normal controls [8-isoprostane (geometric mean (95% CI) 0.51 (0.17–1.51) vs 0.07 (0.04–0.13) ng/ml, p < 0.01); hydrogen peroxide (13.68 (8.63–21.68) vs 5.89 (3.99–8.69) μM, p < 0.05), as well as increased EBC total protein (17.27 (10.57–28.23) vs 7.62 (5.13–11.34) μg/ml, p < 0.05), and fractional exhaled nitric oxide (mean ± SD) (9.67 ± 3.26 vs 7.57 ± 1.89 ppb; p < 0.05). EBC pH was lower in subjects with asbestosis compared with subjects with DPT (7.26 ± 0.31 vs 7.53 ± 0.24; p < 0.05). There were no significant differences in exhaled carbon monoxide, EBC total nitrogen oxides and 3-nitrotyrosine between any of the asbestos-related disorders, or between these and controls.

Conclusion

In asbestos-related disorders, markers of inflammation and oxidative stress are significantly elevated in subjects with asbestosis compared with healthy individuals but not in pleural diseases.