Objectives and achievements of the HUMN project on its 26th anniversary.

Micronuclei (MN) are a nuclear abnormality that occurs when chromosome fragments or whole chromosomes are not properly segregated during mitosis and consequently are excluded from the main nuclei and wrapped within nuclear membrane to form small nuclei. This maldistribution of genetic material leads to abnormal cellular genomes which may increase risk of developmental defects, cancers, and accelerated aging. Despite the potential importance of MN as biomarkers of genotoxicity, very little was known about the optimal way to measure MN in humans, the normal ranges of values of MN in healthy humans and the prospective association of MN with developmental and degenerative diseases prior to the 1980's.

Chromosome-specific induction of micronuclei and chromosomal aberrations by mitomycin C: Involvement of human chromosomes 9, 1 and 16.

Cytogenetic studies have shown that human chromosomes 1, 9, and 16, with a large heterochromatic region of highly methylated classical satellite DNA, are prone to induction of chromatid breaks and interchanges by mitomycin C (MMC). A couple of studies have indicated that material from chromosome 9, and possibly also from chromosomes 1 and 16, are preferentially micronucleated by MMC. Here, we further examined the chromosome-specific induction of micronuclei (MN; with and without cytochalasin B) and chromosomal aberrations (CAs) by MMC.

HBM4EU Chromates Study-Genotoxicity and Oxidative Stress Biomarkers in Workers Exposed to Hexavalent Chromium.

A study was conducted within the European Human Biomonitoring Initiative (HBM4EU) to characterize occupational exposure to Cr(VI). Herein we present the results of biomarkers of genotoxicity and oxidative stress, including micronucleus analysis in lymphocytes and reticulocytes, the comet assay in whole blood, and malondialdehyde and 8-oxo-2′-deoxyguanosine in urine. Workers from several Cr(VI)-related industrial activities and controls from industrial (within company) and non-industrial (outwith company) environments were included.

Biomarkers of nanomaterials hazard from multi-layer data.

There is an urgent need to apply effective, data-driven approaches to reliably predict engineered nanomaterial (ENM) toxicity. Here we introduce a predictive computational framework based on the molecular and phenotypic effects of a large panel of ENMs across multiple in vitro and in vivo models. Our methodology allows for the grouping of ENMs based on multi-omics approaches combined with robust toxicity tests.

Effect of Surface Modification on the Pulmonary and Systemic Toxicity of Cellulose Nanofibrils.

Cellulose nanofibrils (CNFs) have emerged as sustainable options for a wide range of applications. However, the high aspect ratio and biopersistence of CNFs raise concerns about potential health effects. Here, we evaluated the in vivo pulmonary and systemic toxicity of unmodified (U-CNF), carboxymethylated (C-CNF), and TEMPO (2,2,6,6-tetramethyl-piperidin-1-oxyl)-oxidized (T-CNF) CNFs, fibrillated in the same way and administered to mice by repeated (3×) pharyngeal aspiration (14, 28, and 56 μg/mouse/aspiration).

Surface functionalization and size modulate the formation of reactive oxygen species and genotoxic effects of cellulose nanofibrils.

Background: Cellulose nanofibrils (CNFs) have emerged as a sustainable and environmentally friendly option for a broad range of applications. The fibrous nature and high biopersistence of CNFs call for a thorough toxicity assessment, but it is presently unclear which physico-chemical properties could play a role in determining the potential toxic response to CNF. Here, we assessed whether surface composition and size could modulate the genotoxicity of CNFs in human bronchial epithelial BEAS-2B cells.

Toxicogenomic Profiling of 28 Nanomaterials in Mouse Airways.

Toxicogenomics opens novel opportunities for hazard assessment by utilizing computational methods to map molecular events and biological processes. In this study, the transcriptomic and immunopathological changes associated with airway exposure to a total of 28 engineered nanomaterials (ENM) are investigated. The ENM are selected to have different core (Ag, Au, TiO, CuO, nanodiamond, and multiwalled carbon nanotubes) and surface chemistries (COOH, NH, or polyethylene glycosylation (PEG)).

Role of Surface Chemistry in the In Vitro Lung Response to Nanofibrillated Cellulose.

Wood-derived nanofibrillated cellulose (NFC) has emerged as a sustainable material with a wide range of applications and increasing presence in the market. Surface charges are introduced during the preparation of NFC to facilitate the defibrillation process, which may also alter the toxicological properties of NFC. In the present study, we examined the in vitro toxicity of NFCs with five surface chemistries: nonfunctionalized, carboxymethylated, phosphorylated, sulfoethylated, and hydroxypropyltrimethylammonium-substituted.

Pulmonary toxicity of synthetic amorphous silica - effects of porosity and copper oxide doping.

Materials can be modified for improved functionality. Our aim was to test whether pulmonary toxicity of silica nanomaterials is increased by the introduction of: a) porosity; and b) surface doping with CuO; and whether c) these modifications act synergistically. Mice were exposed by intratracheal instillation and for some doses also oropharyngeal aspiration to: 1) solid silica 100 nm; 2) porous silica 100 nm; 3) porous silica 100 nm with CuO doping; 4) solid silica 300 nm; 5) porous silica 300 nm; 6) solid silica 300 nm with CuO doping; 7) porous silica 300 nm with CuO doping; 8) CuO nanoparticles 9.

Genotoxicity and cellular uptake of nanosized and fine copper oxide particles in human bronchial epithelial cells in vitro.

We studied the genotoxicity and cellular uptake of nanosized (<50 nm) and fine (<10 μm) copper oxide (CuO) particles in vitro in human bronchial epithelial (BEAS-2B) cells. In addition, the effect of dispersing the particles using bovine serum albumin (BSA) on DNA damage induction was investigated. DNA damage was assessed by the alkaline comet (single cell gel electrophoresis) assay after 3-h, 6-h and 24-h exposures.

Size, Surface Functionalization, and Genotoxicity of Gold Nanoparticles In Vitro.

Several studies suggested that gold nanoparticles (NPs) could be genotoxic in vitro and in vivo. However, gold NPs currently produced present a wide range of sizes and functionalization, which could affect their interactions with the environment or with biological structures and, thus, modify their toxic effects. In this study, we investigated the role of surface charge in determining the genotoxic potential of gold NPs, as measured by the induction of DNA damage (comet assay) and chromosomal damage (micronucleus assay) in human bronchial epithelial BEAS-2B cells.

Pulmonary effects of nanofibrillated celluloses in mice suggest that carboxylation lowers the inflammatory and acute phase responses.

We studied if the pulmonary and systemic toxicity of nanofibrillated celluloses can be reduced by carboxylation. Nanofibrillated celluloses administered at 6 or 18 μg to mice by intratracheal instillation were: 1) FINE NFC, 2-20 μm in length, 2-15 nm in width, 2) AS (-COOH), carboxylated, 0.5-10 μm in length, 4-10 nm in width, containing the biocide BIM MC4901 and 3) BIOCID FINE NFC: as (1) but containing BIM MC4901.

In vivo toxicological evaluation of polymer brush engineered nanoceria: impact of brush charge.

Nanoceria has a broad variety of industrial and pharmacological applications due to its antioxidant activity. Nanoceria can be modified by surface coating with polyelectrolyte brushes. Brushes can increase the surface charge of nanoceria, providing greater aqueous stability while reducing agglomeration.

Nanofibrillated cellulose causes acute pulmonary inflammation that subsides within a month.

Nanofibrillated cellulose (NFC) is a renewable nanomaterial that has beneficial uses in various applications such as packaging materials and paper. Like carbon nanotubes (CNT), NFCs have high aspect ratio and favorable mechanical properties. The aspect ratio also rises a concern whether NFC could pose a health risk and induce pathologies, similar to those triggered by multi-walled CNT.

Safety Aspects of Bio-Based Nanomaterials.

Moving towards a bio-based and circular economy implies a major focus on the responsible and sustainable utilization of bio-resources. The emergence of nanotechnology has opened multiple possibilities, not only in the existing industrial sectors, but also for completely novel applications of nanoscale bio-materials, the commercial exploitation of which has only begun during the last few years. Bio-based materials are often assumed not to be toxic.

A theoretical approach for a weighted assessment of the mutagenic potential of nanomaterials.

Several approaches have recently been proposed for predicting the potential hazard and risk to human health of engineered nanomaterials (NMs). Here, we present a theoretical approach to assess the mutagenic potential of NMs, which could be incorporated into risk assessment tools. Following the weight of evidence approach recommended for chemicals, we describe criteria for evaluating and weighting existing literature information, based on current knowledge on the relevance and limitations of genotoxicity and mutagenicity assays used in testing NMs.

Genotoxic and inflammatory effects of nanofibrillated cellulose in murine lungs.

Nanofibrillated cellulose (NFC) is a sustainable and renewable nanomaterial, with diverse potential applications in the paper and medical industries. As NFC consists of long fibres of high aspect ratio, we examined here whether TEMPO-(2,2,6,6-tetramethyl-piperidin-1-oxyl) oxidised NFC (length 300-1000nm, thickness 10-25nm), administrated by a single pharyngeal aspiration, could be genotoxic to mice, locally in the lungs or systemically in the bone marrow. Female C57Bl/6 mice were treated with four different doses of NFC (10, 40, 80 and 200 µg/mouse), and samples were collected 24h later.

Effect of particle size and dispersion status on cytotoxicity and genotoxicity of zinc oxide in human bronchial epithelial cells.

Data available on the genotoxicity of zinc oxide (ZnO) nanoparticles (NPs) are controversial. Here, we examined the effects of particle size and dispersion status on the cytotoxicity and genotoxicity of nanosized and fine ZnO, in the presence and absence of bovine serum albumin (BSA; 0.06%) in human bronchial epithelial BEAS-2B cells.

Biomarkers of exposure, effect, and susceptibility in workers exposed to chloronitrobenzenes.

Biomonitoring methods were applied to workers exposed to high levels of chloronitrobenzenes. The external dose, internal dose, biologically effective dose, and biological effects were determined. Individual susceptibility was assessed by analyzing genetic polymorphisms of glutathione S-transferases M1, P1 and T1, and N-acetyltransferases 1 and 2.

In vitro and in vivo genotoxic effects of straight versus tangled multi-walled carbon nanotubes.

Some multi-walled carbon nanotubes (MWCNTs) induce mesothelioma in rodents, straight MWCNTs showing a more pronounced effect than tangled MWCNTs. As primary and secondary genotoxicity may play a role in MWCNT carcinogenesis, we used a battery of assays for DNA damage and micronuclei to compare the genotoxicity of straight (MWCNT-S) and tangled MWCNTs (MWCNT-T) in vitro (primary genotoxicity) and in vivo (primary or secondary genotoxicity). C57Bl/6 mice showed a dose-dependent increase in DNA strand breaks, as measured by the comet assay, in lung cells 24 h after a single pharyngeal aspiration of MWCNT-S (1-200 μg/mouse).

Visualization of Nanofibrillar Cellulose in Biological Tissues Using a Biotinylated Carbohydrate Binding Module of β-1,4-Glycanase.

Nanofibrillar cellulose is a very promising innovation with diverse potential applications including high quality paper, coatings, and drug delivery carriers. The production of nanofibrillar cellulose on an industrial scale may lead to increased exposure to nanofibrillar cellulose both in the working environment and the general environment. Assessment of the potential health effects following exposure to nanofibrillar cellulose is therefore required.

Extensive temporal transcriptome and microRNA analyses identify molecular mechanisms underlying mitochondrial dysfunction induced by multi-walled carbon nanotubes in human lung cells.

Understanding toxicity pathways of engineered nanomaterials (ENM) has recently been brought forward as a key step in twenty-first century ENM risk assessment. Molecular mechanisms linked to phenotypic end points is a step towards the development of toxicity tests based on key events, which may allow for grouping of ENM according to their modes of action. This study identified molecular mechanisms underlying mitochondrial dysfunction in human bronchial epithelial BEAS 2B cells following exposure to one of the most studied multi-walled carbon nanotubes (Mitsui MWCNT-7).

Genotoxic and immunotoxic effects of cellulose nanocrystals in vitro.

Nanocellulosics are among the most promising innovations for a wide-variety of applications in materials science. Although nanocellulose is presently produced only on a small scale, its possible toxic effects should be investigated at this early stage. The aim of the present study was to examine the potential genotoxicity and immunotoxicity of two celluloses in vitro - cellulose nanocrystals (CNC; mean fibril length 135 nm, mean width 7.

Range-finding risk assessment of inhalation exposure to nanodiamonds in a laboratory environment.

This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers' risk range of inhalation exposure to nanodiamonds (NDs) during handling and sieving of ND powder.

Free radical scavenging and formation by multi-walled carbon nanotubes in cell free conditions and in human bronchial epithelial cells.

Background: Certain multi-walled carbon nanotubes (MWCNTs) have been shown to elicit asbestos-like toxicological effects. To reduce needs for risk assessment it has been suggested that the physicochemical characteristics or reactivity of nanomaterials could be used to predict their hazard. Fibre-shape and ability to generate reactive oxygen species (ROS) are important indicators of high hazard materials.