Correction: Brandão et al. Genotoxicity and Gene Expression in the Rat Lung Tissue following Instillation and Inhalation of Different Variants of Amorphous Silica Nanomaterials (aSiO NM). 2021, , 1502.

In the original publication [...

Multiparametric genotoxicity assessment of different variants of amorphous silica nanomaterials in rat alveolar epithelial cells.

The hazard posed to human health by inhaled amorphous silica nanomaterials (aSiO NM) remains uncertain. Herein, we assessed the cyto- and genotoxicity of aSiO NM variants covering different sizes (7, 15, and 40 nm) and surface modifications (unmodified, phosphonate-, amino- and trimethylsilyl-modified) on rat alveolar epithelial (RLE-6TN) cells. Cytotoxicity was evaluated at 24 h after exposure to the aSiO NM variants by the lactate dehydrogenase (LDH) release and WST-1 reduction assays, while genotoxicity was assessed using different endpoints: DNA damage (single- and double-strand breaks [SSB and DSB]) by the comet assay for all aSiO NM variants; cell cycle progression and γ-H2AX levels (DSB) by flow cytometry for those variants that presented higher cytotoxic and DNA damaging potential.

Nanomaterials induce different levels of oxidative stress, depending on the used model system: Comparison of in vitro and in vivo effects.

The immense diversity and constant development of nanomaterials (NMs) increase the need for a facilitated risk assessment, which requires knowledge of the modes of action (MoAs) of NMs. This necessitates a comprehensive data basis, which can be obtained using omics. Furthermore, the establishment of suitable in vitro test systems is essential to follow the 3R concept and to cope with the high number of NMs.

Genotoxicity and Gene Expression in the Rat Lung Tissue following Instillation and Inhalation of Different Variants of Amorphous Silica Nanomaterials (aSiO NM).

Several reports on amorphous silica nanomaterial (aSiO NM) toxicity have been questioning their safety. Herein, we investigated the in vivo pulmonary toxicity of four variants of aSiO NM: SiO_15_Unmod, SiO_15_Amino, SiO_7 and SiO_40. We focused on alterations in lung DNA and protein integrity, and gene expression following single intratracheal instillation in rats.

Model Complexity as Determining Factor for In Vitro Nanosafety Studies: Effects of Silver and Titanium Dioxide Nanomaterials in Intestinal Models.

With the rising interest in the effects of orally ingested engineered nanomaterials (ENMs), much effort is undertaken to develop and advance intestinal in vitro models. The cytotoxic, proinflammatory, and DNA damaging properties of polyvinylpyrrolidone-capped silver (Ag-PVP) and titanium dioxide (TiO , P25) ENM in four in vitro models of increasing complexity-from proliferating Caco-2 and HT29-MTX-E12 monocultures to long-term transwell triple cultures including THP-1 macrophages to reproduce the human intestine in healthy versus inflamed-like state-are studied. Results are compared against in vivo effects of the same ENM through intestinal tissue analysis from 28-day oral exposure studies in mice.

Evaluation of the NLRP3 Inflammasome Activating Effects of a Large Panel of TiO Nanomaterials in Macrophages.

TiO nanomaterials are among the most commonly produced and used engineered nanomaterials (NMs) in the world. There is controversy regarding their ability to induce inflammation-mediated lung injuries following inhalation exposure. Activation of the NACHT, LRR and PYD domains-containing protein 3 (NALP3) inflammasome and subsequent release of the cytokine interleukin (IL)-1β in pulmonary macrophages has been postulated as an essential pathway for the inflammatory and associated tissue-remodeling effects of toxic particles.

Metabolomics profiling to investigate nanomaterial toxicity and .

Nanomaterials (NMs) can be produced in plenty of variants posing several challenges for NM hazard and risk assessment. Metabolomic profiling of NM-treated cells and tissues allows for insights into underlying Mode-of-Action (MoA) and offers several advantages in this context. It supports the description of Adverse Outcome Pathways (AOPs) and, therefore, tailored AOP-based hazard testing strategies.

A multi-omics approach reveals mechanisms of nanomaterial toxicity and structure-activity relationships in alveolar macrophages.

In respect to the high number of released nanomaterials and their highly variable properties, novel grouping approaches are required based on the effects of nanomaterials. Proper grouping calls for a combination of an experimental setup with a higher number of structurally similar nanomaterials and for employing integrated omics approaches to identify the mode of action. Here, we analyzed the effects of seven well-characterized NMs comprising different chemical compositions, sizes and chemical surface modifications on the rat alveolar macrophage cell line NR8383.

An in-depth multi-omics analysis in RLE-6TN rat alveolar epithelial cells allows for nanomaterial categorization.

Background: Nanomaterials (NMs) can be fine-tuned in their properties resulting in a high number of variants, each requiring a thorough safety assessment. Grouping and categorization approaches that would reduce the amount of testing are in principle existing for NMs but are still mostly conceptual. One drawback is the limited mechanistic understanding of NM toxicity.

The nanoGRAVUR framework to group (nano)materials for their occupational, consumer, environmental risks based on a harmonized set of material properties, applied to 34 case studies.

The project nanoGRAVUR (BMBF, 2015-2018) developed a framework for grouping of nanomaterials. Different groups may result for each of the three distinct perspectives of occupational, consumer and environmental safety. The properties, methods and descriptors are harmonised between the three perspectives and are based on: Tier 1 intrinsic physico-chemical properties (what they are) or GHS classification of the non-nano-form (human tox, ecotox, physical hazards); Tier 2 extrinsic physico-chemical properties, release from nano-enabled products, in vitro assays with cells (where they go; what they do); Tier 3 case-specific tests, potentially in vivo studies to substantiate the similarity within groups or application-specific exposure testing.

Effects of short-term exposure to fine and ultrafine particles from indoor sources on arterial stiffness - A randomized sham-controlled exposure study.

Objectives: Particulate air pollution is linked to adverse cardiovascular effects, including arterial stiffness. The aim of the study was to investigate the effect of short-term exposure to indoor fine and ultrafine particles on augmentation index (AIx), augmentation pressure (AP), and pulse wave velocity (PWV), early signs of vascular damage.

Methods: We analyzed the association of particle emissions from typical indoor sources (candle burning - CB, toasting bread - TB, and frying sausages - FS) with changes in pulse wave analysis indices in 55 healthy adults in a randomized cross-over controlled exposure study.

Multi-walled carbon nanotubes induce stronger migration of inflammatory cells in vitro than asbestos or granular particles but a similar pattern of inflammatory mediators.

Biopersistent pro-inflammatory fibers are suspected human carcinogens. Cytotoxicity and transcription of pro- and anti-inflammatory mediators of different fibers were investigated in functional relationship to chemotaxis in vitro as a model for fiber-induced inflammation of the lung. We challenged NR8383 rat macrophages with multi-walled carbon nanotubes (MWCNT) and various asbestos fibers.

Ultrafine and Fine Particle Number and Surface Area Concentrations and Daily Cause-Specific Mortality in the Ruhr Area, Germany, 2009-2014.

Background: Although epidemiologic studies have shown associations between particle mass and daily mortality, evidence on other particle metrics is weak.

Objectives: We investigated associations of size-specific particle number concentration (PNC) and lung-deposited particle surface area concentration (PSC) with cause-specific daily mortality in contrast to PM.

Methods: We used time-series data (March 2009-December 2014) on daily natural, cardiovascular, and respiratory mortality (NM, CVM, RM) of three adjacent cities in the Ruhr Area, Germany.

Arterial blood pressure responses to short-term exposure to fine and ultrafine particles from indoor sources - A randomized sham-controlled exposure study of healthy volunteers.

Objectives: Particulate air pollution is linked to adverse cardiovascular effects. The aim of the study was to investigate the effect of short-term exposure to indoor particles on blood pressure (BP).

Methods: We analyzed the association of particle emissions from indoor sources (candle burning, toasting bread, frying sausages) with BP changes in 54 healthy volunteers in a randomized cross-over controlled exposure study.

Silver nanoparticles induce hormesis in A549 human epithelial cells.

Despite the gaps in our knowledge on the toxicity of silver nanoparticles (AgNPs), the application of these materials is fast expanding, from medicine, to food as well as the use in consumer products. It has been reported that prolonged exposure might make cells more resistant to AgNPs. This prompted us to investigate if AgNPs may give rise to a hormetic response.

Size matters--The phototoxicity of TiO2 nanomaterials.

Under solar radiation several titanium dioxide nanoparticles (nano-TiO2) are known to be phototoxic for daphnids. We investigated the influence of primary particle size (10, 25, and 220 nm) and ionic strength (IS) of the test medium on the acute phototoxicity of anatase TiO2 particles to Daphnia magna. The intermediate sized particles (25 nm) showed the highest phototoxicity followed by the 10 nm and 220 nm sized particles (median effective concentrations (EC50): 0.

Proteomic analysis of protein carbonylation: a useful tool to unravel nanoparticle toxicity mechanisms.

Background: Oxidative stress, a commonly used paradigm to explain nanoparticle (NP)-induced toxicity, results from an imbalance between reactive oxygen species (ROS) generation and detoxification. As one consequence, protein carbonyl levels may become enhanced. Thus, the qualitative and quantitative description of protein carbonylation may be used to characterize how biological systems respond to oxidative stress induced by NPs.

Agreement of central site measurements and land use regression modeled oxidative potential of PM2.5 with personal exposure.

Oxidative potential (OP) of ambient particulate matter (PM) has been suggested as a health-relevant exposure metric. In order to use OP for exposure assessment, information is needed about how well central site OP measurements and modeled average OP at the home address reflect temporal and spatial variation of personal OP. We collected 96-hour personal, home outdoor and indoor PM2.

Mobility of coated and uncoated TiO2 nanomaterials in soil columns--Applicability of the tests methods of OECD TG 312 and 106 for nanomaterials.

Nanomaterials are commonly used in everyday life products and during their life cycle they can be released into the environment. Soils and sediments are estimated as significant sinks for those nanomaterials. To investigate and assess the behaviour of nanomaterials in soils and sediments standardized test methods are needed.

Oxidative potential of particulate matter at a German motorway.

Ambient particulate matter (PM10) was sampled alongside a motorway in North-Rhine Westphalia, Germany, during a one-year period. In sum, 120 PM10 samples on quartz fibre filters, 60 samples at each side of the motorway, were taken during clear cross-wind direction situations, i.e.

Associations between three specific a-cellular measures of the oxidative potential of particulate matter and markers of acute airway and nasal inflammation in healthy volunteers.

Introduction: We evaluated associations between three a-cellular measures of the oxidative potential (OP) of particulate matter (PM) and acute health effects.

Methods: We exposed 31 volunteers for 5 h to ambient air pollution at five locations: an underground train station, two traffic sites, a farm and an urban background site. Each volunteer visited at least three sites.

Respiratory effects of fine and ultrafine particles from indoor sources--a randomized sham-controlled exposure study of healthy volunteers.

Particulate air pollution is linked to impaired respiratory health. We analyzed particle emissions from common indoor sources (candles burning (CB), toasting bread (TB), frying sausages (FS)) and lung function in 55 healthy volunteers (mean age 33.0 years) in a randomized cross-over controlled exposure study.

Oxidative potential of particulate matter collected at sites with different source characteristics.

Background: The oxidative potential (OP) of particulate matter (PM) has been proposed as a more health relevant metric than PM mass. Different assays exist for measuring OP and little is known about how the different assays compare.

Aim: To assess the OP of PM collected at different site types and to evaluate differences between locations, size fractions and correlation with PM mass and PM composition for different measurement methods for OP.

Oxidant generation and toxicity of size-fractionated ambient particles in human lung epithelial cells.

Exposure to ambient particulate matter (PM) is associated with respiratory and cardiovascular disease and lung cancer. In this study, we used size fractionated PM samples (3-7, 1.5-3, 0.