Exhaled breath condensate biomarkers reflect systemic changes in patients with chronic dioxin intoxication

Abstract

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is highly toxic and affects the cardiovascular system, brain, and skin by AhR-dependent and other mechanisms, as well as causing metabolic impairments and cancer. The involvement of the respiratory system has not yet been studied. TCDD in the blood was measured and biomarkers of oxidative stress and inflammation were analysed in 2016 in the exhaled breath condensate (EBC) of the last eight male survivors (mean age 72.4 ± 1.3 years) from 80 workers intoxicated with TCDD during the production of herbicides from 1965 to 1968. The results were compared with their findings in 2010 to evaluate a trend. Malondialdehyde, 4-hydroxy-trans-nonenale, and 8-isoprostaglandin F2α (8-isoprostane), in addition to markers of the oxidation of nucleic acids and proteins 8-hydroxy-2-deoxyguanosine, 8-hydroxyguanosine, 5-(hydroxymethyl)uracil, o-tyrosine, and 3-nitrotyrosine, as well as markers of inflammation leukotrienes and anti-inflammatory lipoxins, were analysed in EBC by liquid chromatography–electrospray ionisation–tandem mass spectrometry. In addition, the patients underwent chest X-ray, spirometry and fractional exhaled nitric oxide (FeNO) examinations. The control group included 7 men (66 ± 16 years) with comparable lifestyle factors. The median plasma TCDD level lowered from 155 (28–553) ng/kg fat in 2010 to 112 (46–390) ng/kg fat in 2016, i.e., 50 years after exposure. The mean TCDD body deposit was 5.0 ± 3.7 µg. Serum TCDD level in the pooled sample of the controls was 12 ng/kg fat. All markers of oxidative stress, LTB4 and LTC4, remained overexpressed in patients and anti-inflammatory lipoxins were under-expressed compared to controls (all p < 0.01). The mean FeNO and spirometry results were within the reference values. Borderline X-ray findings and combined lung function impairments were seen in the patients with the lower TCDD plasma levels. Differences in the expression of the biomolecular markers in EBC as compared to controls were not associated with lung impairments and the respiratory parameters measured. Therefore, these EBC markers can be used to evaluate systemic oxidative stress and inflammation in tissues and the endovascular, atherosclerotic, neurotoxic, and metabolic effects of TCDD.