Exposure to engineered nanomaterials and early biological effects measured in the exhaled breath condensate: First results from the NanoExplore cohort

Abstract

BACKGROUND AND AIM Activities involving engineered nanomaterials (ENM) may raise concerns of occupational exposure and subsequent health effects. We aimed to build a multicenter prospective cohort to assess the potential effects of ENM exposure using biomarkers of early effects measured in exhaled breath condensate (EBC). METHODS We recruited seven centers in three countries (Switzerland, Spain, and Italy), where we conducted a 4-day exposure monitoring campaign and two EBC samplings, at the beginning (T1) and end (T2) of working week. The recruited workers were split in three groups depending on their exposure and compared in terms of their baseline individual and professional characteristics, and health status. EBC biomarkers of oxidative and nitrosative stress (malondialdehyde, 8-isoprostane, nitrotyrosine), systemic inflammation (High-Sensitivity C-Reactive Protein (hsCRP)), activation of pro-fibrotic cascade and interstitial lung disease (Krebs von den Lungen glycoprotein 6 (KL6)) and inflammatory cytokines (Interleukins (IL-10, IL-1β), Tumor necrosis factor (TNF-α)) were analyzed using multilevel mixed interval regression models. RESULTS The cohort included 140 participants: 43 non-exposed, 55 with negligible to low exposure, and 43 with medium to high exposure. The latter were gradually more often men, older, and in overweight than lowly exposed and non-exposed workers. A statistically significant change between T1 and T2 average concentrations was observed for malondialdehyde and KL6. Between-group differences were observed for all biomarkers but KL6 and nitrotyrosine. In multivariate models adjusted for age, sex and body mass index, a linear exposure-response relationship was observed for malondialdehyde, 8-isoprostane, IL-10, IL-1β, and TNF-α. ENM exposure was also associated with higher hs-CRP and KL6 levels, but not monotonically. CONCLUSION These first results suggest that ENM exposure might lead to early biological effects in workers’ airways. These findings need confirmation and a caution interpretation of their clinical significance, as most effects are non-specific and likely reversible.