Airway inflammation after inhalation of nano-sized zinc oxide particles in human volunteers

Abstract

BackgroundWorkers in the zinc production and processing of galvanized sheet steel are exposed to a complex mixture of particles and gases, including zinc oxide (ZnO) that can affect human health. We aimed to study the effects of short-term controlled exposure to nano-sized ZnO on airway inflammatory markers in healthy volunteers.MethodsSixteen subjects (8 females, 8 men; age 19–42, non-smokers) were exposed to filtered air and ZnO nanoparticles (0.5, 1.0 and 2.0 mg/m3) for 4 h, including 2 h of cycling with a low workload. Induced sputum samples were collected during a medical baseline and a final examination and also about 24 h after each exposure. A number of inflammatory cellular and soluble markers were analyzed.ResultsFrequency and intensity of symptoms of airway irritation (throat irritation and cough) were increased in some subjects 24 h after ZnO exposures when compared to filtered air. The group comparison between filtered air and ZnO exposures showed statistically significant increases of neutrophils and interleukin-8 (IL-8), interleukin-6 (IL-6), matrix metalloproteinase (MMP-9) and tissue inhibitors of metalloproteinases (TIMP-1) in sputum starting at the lowest ZnO concentration of 0.5 mg/m3. However, a concentration-response relationship was absent. Effects were reversible. Strong correlations were found between neutrophil numbers and concentrations of total protein, IL-8, MMP-9, and TIMP-1.ConclusionsControlled exposures of healthy subjects to ZnO nanoparticles induce reversible airway inflammation which was observed at a concentration of 0.5 mg/m3 and higher. The lack of a concentration-response relationship warrants further studies.

Nanotoxicology: The Need for a Human Touch?

“…[ 104 ] To the best of our knowledge, we are aware of only a two sets of experiments that have performed inhalation exposures to a MNM of potentially greater toxicity (excluding combustion‐derived particle studies), both using zinc oxide nanoparticles. [ 105–108 ] Beckett et al. carried out controlled exposure to 0.5 mg m −3 ZnO nanoparticles (≈40 nm count median diameter) in healthy volunteers, and found no effect on subject‐reported symptoms, cardioelectrophysiology (heart rate variability) or blood markers of inflammation or coagulation.…”

“…[ 107 ] The exposure also caused airway inflammation and symptoms of irritation, although the effects were not concentration‐dependent. [ 108 ] There was no indication of oxidative stress (F 2α ‐isoprostane levels) in the sputum, but matrix metalloproteinase‐9 (MMP‐9) levels were increased. The findings provided valuable information to inform the setting of occupational levels of zinc nanoparticles.…”

“…Reproduced under the terms of the CC‐BY Creative Commons Attribution 4.0 International License ( http://creativecommons.org/licenses/by/4.0/). [ 108 ] Copyright 2019, The Authors, published by BioMed Central (part of Springer Nature).…”

COVID-19 and a novel initiative to improve safety by 3D printing personal protective equipment parts from computed tomography

“…Due to a variety of mechanisms, zinc has been suggested as an adjunct for treatment for COVID-19 respiratory infections, [62] mostly due to the observed effect zinc ions have on the RNA polymerase of the corona virus [63]. At the same time, it has been shown that reversible airway inflammation can occur after inhalation of zinc oxide nanoparticles [64].…”

COVID-19 and a novel initiative to improve safety by 3D printing personal protective equipment parts from computed tomography

“…(63) At the same time, it has been shown that reversible airway in ammation can occur after inhalation of zinc oxide nanoparticles. (64)…”