Airborne particulate matter and acute lung inflammation: Strak et al. Respond

Genotoxicity Response of Fibroblast Cells and Human Epithelial Adenocarcinoma In Vitro Model Exposed to Bare and Ozone-Treated Silica Microparticles

Indoor air pollutants (IAP), which can pose a serious risk to human health, include biological pollutants, nitric oxide (NO), nitrogen dioxide (NO2), volatile organic compounds (VOC), sulfur dioxide (SO2), carbon monoxide (CO), carbon dioxide (CO2), silica, metals, radon, and particulate matter (PM). The aim of our work is to conduct a multidisciplinary study of fine silica particles (<2.5 μm) in the presence or absence of ozone (O3), and evaluate their potential cytotoxicity using MTS, micronucleus, and the comet test in two cell lines. We analyzed A549 (human basal alveolar epithelial cell adenocarcinoma) and Hs27 (human normal fibroblasts) exposed to dynamic conditions by an IRC simulator under ozone flow (120 ppb) and in the presence of silica particles (40 μg/h). The viability of A549 and Hs27 cells at 48 and 72 h of exposure to silica or silica/ozone decreases, except at 72 h in Hs27 treated with silica/ozone. The micronucleus and comet tests showed a significant increase in the number of micronuclei and the % of DNA in the queue, compared to the control, in both lines in all treatments, even if in different cell times/types. We found that silica alone or with more O3 causes more pronounced genotoxic effects in A549 tumor cells than in normal Hs27 fibroblasts.

The impact of ambient air pollution on the human blood metabolome

BACKGROUND

Biological perturbations caused by air pollution might be reflected in the compounds present in blood originating from air pollutants and endogenous metabolites influenced by air pollution (defined here as part of the blood metabolome). We aimed to assess the perturbation of the blood metabolome in response to short term exposure to air pollution.

METHODS

We exposed 31 healthy volunteers to ambient air pollution for 5h. We measured exposure to particulate matter, particle number concentrations, absorbance, elemental/organic carbon, trace metals, secondary inorganic components, endotoxin content, gaseous pollutants, and particulate matter oxidative potential. We collected blood from the participants 2h before and 2 and 18h after exposure. We employed untargeted metabolite profiling to monitor 3873 metabolic features in 493 blood samples from these volunteers. We assessed lung function using spirometry and six acute phase proteins in peripheral blood. We assessed the association of the metabolic features with the measured air pollutants and with health markers that we previously observed to be associated with air pollution in this study.

RESULTS

We observed 89 robust associations between air pollutants and metabolic features two hours after exposure and 118 robust associations 18h after exposure. Some of the metabolic features that were associated with air pollutants were also associated with acute health effects, especially changes in forced expiratory volume in 1s. We successfully identified tyrosine, guanosine, and hypoxanthine among the associated features. Bioinformatics approach Mummichog predicted enriched pathway activity in eight pathways, among which tyrosine metabolism.

CONCLUSIONS

This study demonstrates for the first time the application of untargeted metabolite profiling to assess the impact of air pollution on the blood metabolome.

Mutagenic and genotoxic potential of native air borne particulate matter from industrial area of Rourkela city, Odisha, India

In this study, we examined potential adverse health effect of particulate matter (PM) collected from industrial areas of Rourkela, Odisha, India. Results indicate that PM in these areas contains benzo[a]pyrene in addition to other unidentified molecules. Ames test revealed the above PM to be highly mutagenic. Further studies of PM in HaCaT cells suggest its DNA damaging potential which may lead to apoptosis. Generation of reactive oxygen and nitrogen species following PM exposure may be an early event in the PM induced apoptosis. In addition, the activity of cytochrome P450 (CYP450), the key xenobiotic metabolism enzyme, was found to be increased following PM exposure indicating its role in PM induced toxicity. To confirm this, we used genetic and pharmacological inhibitors of CYP450 like CYP1B1 siRNA and Clotrimazole. Interestingly, we found that the use of these inhibitors significantly suppressed the PM induced apoptosis in HaCaT cells, which confirm the crucial role of CYP1B1 in the toxic manifestation of PM. For further analysis, blood samples were collected from the volunteer donor and analyzed for immunophenotypes and comet assay to survey any change in immune cells and DNA damage in blood cells respectively. The study was performed with 55 blood samples including 32 from industrial areas and 23 people from non-industrial zone of Rourkela city. Samples had a mean±SD age of 35±6.2years (35 men and 20 women). Our investigation did not observe any significant alteration in lymphocytes (P=0.671), B cell (P=0.104), cytotoxic T cell (P=0.512), helper T cell (P=0.396), NK cell (P=0.675) and monocytes (P=0.170) of blood cells from these two groups. Taken together; this study first time reports the possible health hazards of PM from industrial areas of Odisha, India.