title: Identification of PM10 characteristics involved in cellular responses in human bronchial epithelial cells (Beas-2B).
abstract: Notwithstanding evidence is present that physicochemical characteristics of ambient particles attribute to adverse health effects, there is still some lack of understanding in this complex relationship. At this moment it is not clear which properties (such as particle size, chemical composition) or sources of the particles are most relevant for health effects. This study investigates the in vitro toxicity of PM10 in relation to PM chemical composition, black carbon (BC), endotoxin content and oxidative potential (OP). In 2013-2014 PM10 was sampled (24h sampling, 108 sampling days) in ambient air at three sites in Flanders (Belgium) with different pollution characteristics: an urban traffic site (Borgerhout), an industrial area (Zelzate) and a rural background location (Houtem). To characterize the toxic potential of PM10, airway epithelial cells (Beas-2B cells) have been exposed to particles in vitro. Different endpoints were studied including cell damage and death (cell viability) using the Neutral red Uptake assay, the production of pro-inflammatory molecules by interleukin 8 (IL-8) induction and DNA-damaging activity using the FPG-modified Comet assay. The endotoxin levels in the collected samples were analysed and the capacity of PM10 particles to produce reactive oxygen species (OP) was evaluated by electron paramagnetic resonance (EPR) spectroscopy. Chemical characteristics of PM10 (BC, As, Cd, Cr, Cu, Mn, Ni, Pb, Zn) and meteorological conditions were recorded on the sampling days. PM10 particles exhibited dose-dependent cytotoxicity in Beas-2B cells and were found to significantly induce the release of IL-8 in samples from the three locations. Oxidatively damaged DNA was observed in exposed Beas-2B cells. Endotoxin levels above the detection limit were detected in half of the samples. OP was measurable in all samples. Associations between PM10 characteristics and biological effects of PM10 were assessed by single and multiple regression analyses. The reduction in cell viability was significantly correlated with BC, Cd and Pb. The induction of IL-8 in Beas-2B cells was significantly associated with Cu, Ni and Zn and endotoxin. Endotoxin levels explained 33% of the variance in IL-8 induction. A significant interaction between ambient temperature and endotoxin on the pro-inflammatory activity was seen. No association was found between OP and the cellular responses. This study supports the hypothesis that, on an equal mass basis, PM10 induced biological effects differ due to differences in PM10 characteristics. Metals (Cd, Cu, Ni and Zn), BC, and endotoxin were among the main determinants for the observed biological responses.
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium. Electronic address: rosette.vandenheuvel@vito.be.
authors.forename: Rosette
authors.initials: R
authors.lastname: Van Den Heuvel
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium. Electronic address: elly.denhond@wiv-isp.be.
authors.forename: Elly
authors.initials: E
authors.lastname: Den Hond
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium. Electronic address: eva.govarts@vito.be.
authors.forename: Eva
authors.initials: E
authors.lastname: Govarts
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium. Electronic address: ann.colles@vito.be.
authors.forename: Ann
authors.initials: A
authors.lastname: Colles
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium. Electronic address: gudrun.koppen@vito.be.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Koppen
authors.affiliation: Flanders Environment Agency (VMM), Unit Air, Kronenburgstraat 45, 2000 Antwerp, Belgium. Electronic address: j.staelens@vmm.be.
authors.forename: Jeroen
authors.initials: J
authors.lastname: Staelens
authors.affiliation: LNE (Environment, Nature and Energy Department), Flemish Government, Koning Albert II-laan 20, 1000 Brussels, Belgium. Electronic address: maja.mampaey@lne.vlaanderen.be.
authors.forename: Maja
authors.initials: M
authors.lastname: Mampaey
authors.affiliation: National Institute for Public Health and the Environment (RIVM), P.O. Box, 2720 BA, Bilthoven, The Netherlands. Electronic address: nicole.janssen@rivm.nl.
authors.forename: Nicole
authors.initials: N
authors.lastname: Janssen
authors.affiliation: Flemish Institute for Technological Research (VITO), Environmental Risk and Health Unit, Boeretang 200, 2400 Mol, Belgium; University of Antwerp, Department of Biomedical Sciences, 2000 Antwerp, Belgium. Electronic address: greet.schoeters@vito.be.
authors.forename: Greet
authors.initials: G
authors.lastname: Schoeters
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D001530:Belgium; D001980:Bronchi / Q000187:drug effects*; D004731:Endotoxins / Q000032:analysis; D004847:Epithelial Cells / Q000187:drug effects; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D053260:Soot / Q000032:analysis
chemical_list: D000393:Air Pollutants; D004731:Endotoxins; D052638:Particulate Matter; D053260:Soot
keywords: Comet assay; Cytotoxicity; Endotoxin; Oxidative potential; Particulate matter; Pro-inflammatory response