AIM: To investigate the effect of acute (daily) inhalation of nanoparticles (NPs) on the transcriptomic profile of male nanocomposite research workers with a history of long-term exposure (years). MATERIALS & METHODS: Whole genome mRNA and miRNA expression changes were analyzed from blood samples collected before and after machining or welding. Exposure in the work environment was assessed using stationary and personal monitoring. RESULTS: Following PM0.1 exposure, a significant decrease in the expression of DDIT4 and FKBP5, genes involved in the stress response, was detected in exposed workers. In the Machining group, the DDIT4 expression correlated with the exposure dose. Increased levels of miR30-d-5p and miR-3613-5p (both involved in carcinogenesis) in welders were associated with the NP exposure dose, highlighting their potential suitability as inhalation exposure markers. CONCLUSION: The results from this pilot transcriptomic analysis (mRNA and miRNA) indicate that exposure to NPs contributes to immune system deregulation and alters the pathways related to cancer. Therefore, the use of protective equipment, as well as obtaining more data by additional research, is highly recommended.

This is a follow-up study to our previous research that examined the acute effects of occupational inhalation exposure to nanoparticles (NPs) in females without a previous exposure history. This time, we reexamined the impacts of acute exposure in a group of 18 male workers, including welders and nanocomposite machinists with a long-term previous exposure history at the transcriptomic level. Whole genome transcriptomics studies the complete set of RNA molecules, or transcripts, produced in a cell or organism at a specific time. The analysis allows us to understand which genes are active/inactive, how they are regulated, and how they contribute to various biological processes or diseases. We looked at changes in mRNA and miRNA (types of RNA) from blood samples taken before and after workers were exposed to dust and fumes during machining and welding. We also monitored the exposure doses. The results suggest that inhaled NPs may present an occupational hazard to human health. The transcriptomic analysis shows that exposure to welding fumes and nanocomposite dust from machining affects the immune system and alters cancer-related pathways. Our research helps to understand NP exposure effects and may contribute to minimizing the negative health consequences of their inhalation.

• Keywords
• Occupational exposure, machining, nanoparticles, transcriptome changes, welding,
• MeSH
• Adult MeSH
• Inhalation Exposure adverse effects   analysis   MeSH
• Middle Aged MeSH
• Humans MeSH
• RNA, Messenger genetics   blood   MeSH
• MicroRNAs genetics   blood   MeSH
• Nanoparticles * adverse effects   MeSH
• Occupational Exposure * adverse effects   analysis   MeSH
• Gene Expression Profiling MeSH
• Transcriptome * drug effects   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• RNA, Messenger MeSH
• MicroRNAs MeSH

OBJECTIVES: Nanotechnology is a fast-growing field in both science and industry. However, experimental studies brought warning data concerning the negative effect of engineered nanoparticle exposure leading to oxidative stress, inflammation, decreased immune cell viability, and genotoxicity. The consequences of human exposure may appear with decades of latency. Therefore, more data is needed to identify the hazardous effects of nanoparticles. Exposure should be under control and biomarkers of effect are urgently searched. METHODS: Exposures of researchers working with nanocomposites were measured in yearly intervals for 5 years and biomarkers of oxidative stress and/or antioxidant capacity were analysed. Exposure to aerosols with nanoparticles was measured repeatedly using online and offline instruments during both the machining of geopolymer samples with epoxide resin and nanoSiO2 filler and metal surface welding. The levels of biomarkers of oxidation of lipids, nucleic acids and proteins were analysed in exhaled breath condensate (EBC) of researchers and controls in 2016-2018. In 2019 and 2020, glutathione was measured in plasma to assess their antioxidant status. The trends in both exposure and EBC biomarkers' levels were analysed. RESULTS: On average, 21 researchers were examined yearly (aged 40 ± 5 years, exposure 14 ± 3 years). After 5 years, the mean mass concentration dropped from 0.921 to 0.563 mg/m3 and mean total number of particle concentrations from 146,106 to 17,621/cm3. The majority of biomarkers of oxidation of lipids, proteins and nucleic acids decreased (p < 0.05) during repeated measurements from the highest levels being mostly found in 2016. Glutathione in plasma in 2019-2020 was elevated (p < 0.01) as compared to controls. CONCLUSIONS: The adaptation of long-term exposed researchers may give a plausible explanation. However, to our meaning, the precautionary principle and higher attention of the employers to the potential risk of nanoparticles by reducing nanoparticles exposure by almost one order of magnitude played the key role.

• Keywords
• adaptation, engineered nanoparticles, oxidative stress, prevention, spirometry,
• MeSH
• Biomarkers analysis   MeSH
• Adult MeSH
• Humans MeSH
• Nanoparticles adverse effects   MeSH
• Nanostructures * adverse effects   MeSH
• Oxidative Stress MeSH
• Occupational Exposure * prevention & control   analysis   MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Biomarkers MeSH

Conventional dry machining (without process media) of carbon fibre composite materials (CFRP) produces tiny chips/dust particles that float in the air and cause health hazards to the machining operator. The present study investigates the effect of cutting conditions (cutting speed, feed per tooth and depth of cut) during CFRP milling on the size, shape and amount of harmful dust particles. For the present study, one type of cutting tool (CVD diamond-coated carbide) was used directly for machining CFRP. The analysis of harmful dust particles was carried out on a Tescan Mira 3 (Tescan, Brno, Czech Republic) scanning electron microscope and a Keyence VK-X 1000 (Keyence, Itasca, IL, USA) confocal microscope. The results show that with the combination of higher feed per tooth (mm) and lower cutting speed, for specific CFRP materials, the size and shape of harmful dust particles is reduced. Particles ranging in size from 2.2 to 99 μm were deposited on the filters. Smaller particles were retained on the tool body (1.7 to 40 μm). Similar particle sizes were deposited on the machine and in the work area.

• Keywords
• CFRP, dust particles, electron microscopy, milling, respiratory hazards,
• Publication type
• Journal Article MeSH

The evaluation of the frequency of micronuclei (MN) is a broadly utilised approach in in vitro toxicity testing. Nevertheless, the specific properties of nanomaterials (NMs) give rise to concerns regarding the optimal methodological variants of the MN assay. In bronchial epithelial cells (BEAS-2B), we tested the genotoxicity of five types of NMs (TiO2: NM101, NM103; SiO2: NM200; Ag: NM300K, NM302) using four variants of MN protocols, differing in the time of exposure and the application of cytochalasin-B combined with the simultaneous and delayed co-treatment with NMs. Using transmission electron microscopy, we evaluated the impact of cytochalasin-B on the transport of NMs into the cells. To assess the behaviour of NMs in a culture media for individual testing conditions, we used dynamic light scattering measurement. The presence of NMs in the cells, their intracellular aggregation and dispersion properties were comparable when tests with or without cytochalasin-B were performed. The genotoxic potential of various TiO2 and Ag particles differed (NM101 < NM103 and NM302 < NM300K, respectively). The application of cytochalasin-B tended to increase the percentage of aberrant cells. In conclusion, the comparison of the testing strategies revealed that the level of DNA damage induced by NMs is affected by the selected methodological approach. This fact should be considered in the interpretation of the results of genotoxicity tests.

• Keywords
• DLS, cell line, genotoxicity, micronucleus assay, nanomaterials,
• Publication type
• Journal Article MeSH

Human data concerning exposure to nanoparticles are very limited, and biomarkers for monitoring exposure are urgently needed. In a follow-up of a 2016 study in a nanocomposites plant, in which only exhaled breath condensate (EBC) was examined, eight markers of oxidative stress were analyzed in three bodily fluids, i.e., EBC, plasma and urine, in both pre-shift and post-shift samples in 2017 and 2018. Aerosol exposures were monitored. Mass concentration in 2017 was 0.351 mg/m3 during machining, and 0.179 and 0.217 mg/m3 during machining and welding, respectively, in 2018. In number concentrations, nanoparticles formed 96%, 90% and 59%, respectively. In both years, pre-shift elevations of 50.0% in EBC, 37.5% in plasma and 6.25% in urine biomarkers were observed. Post-shift elevation reached 62.5% in EBC, 68.8% in plasma and 18.8% in urine samples. The same trend was observed in all biological fluids. Individual factors were responsible for the elevation of control subjects' afternoon vs. morning markers in 2018; all were significantly lower compared to those of workers. Malondialdehyde levels were always acutely shifted, and 8-hydroxy-2-deoxyguanosine levels best showed chronic exposure effect. EBC and plasma analysis appear to be the ideal fluids for bio-monitoring of oxidative stress arising from engineered nanomaterials. Potential late effects need to be targeted and prevented, as there is a similarity of EBC findings in patients with silicosis and asbestosis.

• Keywords
• biomarkers, controls, exhaled breath condensate, nanoparticles, oxidative stress, plasma, urine, workers,
• Publication type
• Journal Article MeSH

The exposure of living organisms to environmental stress triggers defensive responses resulting in the activation of protective processes. Whenever the exposure occurs at low doses, defensive effects overwhelm the adverse effects of the exposure; this adaptive situation is referred to as "hormesis". Environmental, physical, and nutritional hormetins lead to the stimulation and strengthening of the maintenance and repair systems in cells and tissues. Exercise, heat, and irradiation are examples of physical hormetins, which activate heat shock-, DNA repair-, and anti-oxidative-stress responses. The health promoting effect of many bio-actives in fruits and vegetables can be seen as the effect of mildly toxic compounds triggering this adaptive stimulus. Numerous studies indicate that living organisms possess the ability to adapt to adverse environmental conditions, as exemplified by the fact that DNA damage and gene expression profiling in populations living in the environment with high levels of air pollution do not correspond to the concentrations of pollutants. The molecular mechanisms of the hormetic response include modulation of (a) transcription factor Nrf2 activating the synthesis of glutathione and the subsequent protection of the cell; (b) DNA methylation; and (c) microRNA. These findings provide evidence that hormesis is a toxicological event, occurring at low exposure doses to environmental stressors, having the benefit for the maintenance of a healthy status.

• Keywords
• adaptive response, microRNA machinery, preventive medicine,
• MeSH
• Epigenesis, Genetic * MeSH
• Adaptation, Physiological * MeSH
• Stress, Physiological * MeSH
• Hormesis * MeSH
• Humans MeSH
• Oxidative Stress MeSH
• DNA Damage MeSH
• Gene Expression Regulation MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Review MeSH

The risk of exposure to nanoparticles (NPs) has rapidly increased during the last decade due to the vast use of nanomaterials (NMs) in many areas of human life. Despite this fact, human biomonitoring studies focused on the effect of NP exposure on DNA alterations are still rare. Furthermore, there are virtually no epigenetic data available. In this study, we investigated global and gene-specific DNA methylation profiles in a group of 20 long-term (mean 14.5 years) exposed, nanocomposite, research workers and in 20 controls. Both groups were sampled twice/day (pre-shift and post-shift) in September 2018. We applied Infinium Methylation Assay, using the Infinium MethylationEPIC BeadChips with more than 850,000 CpG loci, for identification of the DNA methylation pattern in the studied groups. Aerosol exposure monitoring, including two nanosized fractions, was also performed as proof of acute NP exposure. The obtained array data showed significant differences in methylation between the exposed and control groups related to long-term exposure, specifically 341 CpG loci were hypomethylated and 364 hypermethylated. The most significant CpG differences were mainly detected in genes involved in lipid metabolism, the immune system, lung functions, signaling pathways, cancer development and xenobiotic detoxification. In contrast, short-term acute NP exposure was not accompanied by DNA methylation changes. In summary, long-term (years) exposure to NP is associated with DNA epigenetic alterations.

• Keywords
• 850K microarray, CpG sites, DNA methylation, epigenetic adaptation, human, nanoparticles, occupational exposure,
• MeSH
• Adult MeSH
• Epigenesis, Genetic MeSH
• Genome, Human MeSH
• Middle Aged MeSH
• Humans MeSH
• DNA Methylation drug effects   MeSH
• Young Adult MeSH
• Nanoparticles adverse effects   MeSH
• Nanocomposites adverse effects   MeSH
• Occupational Exposure * MeSH
• Aged MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH