Differential pulmonary toxicity and autoantibody formation in genetically distinct mouse strains following combined exposure to silica and diesel exhaust particles.

BACKGROUND: Inhalation of airborne particulate matter, such as silica and diesel exhaust particles, poses serious long-term respiratory and systemic health risks. Silica exposure can lead to silicosis and systemic autoimmune diseases, while DEP exposure is linked to asthma and cancer. Combined exposure to silica and DEP, common in mining, may have more severe effects. This study investigates the separate and combined effects of occupational-level silica and ambient-level DEP on lung injury, inflammation, and autoantibody formation in two genetically distinct mouse strains, thereby aiming at understanding the interplay between genetic susceptibility, particulate exposure, and disease outcomes. Silica and diesel exhaust particles were administered to mice via oropharyngeal aspiration. Assessments of lung injury and host response included in vivo lung micro-computed tomography, lung function tests, bronchoalveolar lavage fluid analysis including inflammatory cytokines and antinuclear antibodies, and histopathology with particle colocalization. RESULTS: The findings highlight the distinct effects of silica and diesel exhaust particles (DEP) on lung injury, inflammation, and autoantibody formation in C57BL/6J and NOD/ShiLtJ mice. Silica exposure elicited a well-established inflammatory response marked by inflammatory infiltrates, release of cytokines, and chemokines, alongside mild fibrosis, indicated by collagen deposition in the lungs of both C57BL/6J and NOD/ShilLtJ mice. Notably, these strains exhibited divergent responses in terms of respiratory function and lung volumes, as assessed through micro-computed tomography. Additionally, silica exposure induced airway hyperreactivity and elevated antinuclear antibody levels in bronchoalveolar lavage fluid, particularly prominent in NOD/ShiLtJ mice. Moreover, antinuclear antibodies correlated with extent of lung inflammation in NOD/ShiLTJ mice. Lung tissue analysis revealed DEP loaded macrophages and co-localization of silica and DEP particles. However, aside from contributing to airway hyperreactivity specifically in NOD/ShiLtJ mice, the ambient-level DEP did not significantly amplify the effects induced by silica. There was no evidence of synergistic or additive interaction between these specific doses of silica and DEP in inducing lung damage or inflammation in either of the mouse strains. CONCLUSION: Mouse strain variations exerted a substantial influence on the development of silica induced lung alterations. Furthermore, the additional impact of ambient-level DEP on these silica-induced effects was minimal.

Development and validation of a human bronchial epithelial spheroid model to study respiratory toxicity in vitro.

The use of laboratory animals in research has been extensively criticized. While most of the critique has been centered around the ethical aspect, also the economic and scientific aspects have been frequently mentioned as points of concern. As a result, the use of alternative methods has gradually become more enticing. The most used alternatives to laboratory animals are the 2D monolayer cell cultures. However, the limited translatability of these monolayer cell cultures to in vivo has led to the development of 3D cell cultures that are believed to better capture the in vivo physiology and pathology. Here we report on the development of a physiologically more relevant 3D cell model (spheroids) comprised of human bronchial epithelial (16HBE14o-) cells, for use in respiratory toxicity research. Culturing 16HBE14o-cells as hanging-drops led to the formation of stable spheroids which showed an increased expression of CLDN1 when compared to 2D monolayer cultured cells. In addition, cell-cycle analysis revealed an increased sub-G0 population and signs of G0/G1 arrest in spheroids. Afterwards, standard operating procedures (SOPs) were established, and existing protocols optimized, for compatibility with spheroids. Spheroids were successfully used to assess cytotoxicity, genotoxicity, apoptosis/necrosis, and oxidative stress after exposure to known cytotoxic or genotoxic compounds. The development of the bronchial epithelial spheroids and the establishment of SOPs can contribute to a more reliable toxicity assessment of chemicals and may aid in bridging the gap between in vivo and in vitro experiments.

Data management and protection in occupational and environmental exposome research - A case study from the EU-funded EXIMIOUS project.

Within collaborative projects, such as the EU-funded Horizon 2020 EXIMIOUS project (Mapping Exposure-Induced Immune Effects: Connecting the Exposome and the Immunome), collection and analysis of large volumes of data pose challenges in the domain of data management, with regards to both ethical and legal aspects. However, researchers often lack the right tools and/or accurate understanding of the ethical/legal framework to independently address such challenges. With the guidance and support within and between the partner institutes (the researchers and the ethical and legal teams) in the EXIMIOUS project, we have been able to understand and solve most challenges during the first two project years. This has fed into the development of a Data Management Plan and the establishment of data management platforms in accordance with the ethical and legal framework laid down by the EU and the different national regulations of the partners involved. Through this elaborate exercise, we have acquired tools which allow us to make our research data FAIR (Findable, Accessible, Interoperable, and Reusable), while at the same time ensuring data privacy and security (GDPR compliant). Herein we share our experience of creating and managing the data workflow through an open research communication, with the aim of helping other researchers build their data management framework in their own projects. Based on the measures adopted in EXIMIOUS to ensure FAIR data management, we also put together a checklist "DMP CHECK" containing a series of recommendations based on our experience.

Characterization of the internal working-life exposome using minimally and non-invasive sampling methods - a narrative review.

During recent years, we are moving away from the 'one exposure, one disease'-approach in occupational settings and towards a more comprehensive approach, taking into account the totality of exposures during a life course by using an exposome approach. Taking an exposome approach however is accompanied by many challenges, one of which, for example, relates to the collection of biological samples. Methods used for sample collection in occupational exposome studies should ideally be minimally invasive, while at the same time sensitive, and enable meaningful repeated sampling in a large population and over a longer time period. This might be hampered in specific situations e.g., people working in remote areas, during pandemics or with flexible work hours. In these situations, using self-sampling techniques might offer a solution. Therefore, our aim was to identify existing self-sampling techniques and to evaluate the applicability of these techniques in an occupational exposome context by conducting a literature review. We here present an overview of current self-sampling methodologies used to characterize the internal exposome. In addition, the use of different biological matrices was evaluated and subdivided based on their level of invasiveness and applicability in an occupational exposome context. In conclusion, this review and the overview of self-sampling techniques presented herein can serve as a guide in the design of future (occupational) exposome studies while circumventing sample collection challenges associated with exposome studies.

Systematic review of genotoxicity induced by occupational exposure to antineoplastic drugs.

With increasing numbers of cancer cases, the use of antineoplastic agents is expected to rise. This will be accompanied by an increase in occupational exposure, which can cause unwanted health effects in workers. Our aim was to give an overview of genotoxic and epigenetic effects after occupational exposure to antineoplastic agents and to assess the concentration-effect relation. Four databases were searched for papers investigating genotoxic and/or epigenetic effects of occupational exposure to antineoplastic agents. Out of the 245 retrieved papers, 62 were included in this review. In this systematic literature review, we confirmed that exposure of healthcare workers to antineoplastic agents can lead to genotoxic damage. However, we observed a lack of data on exposure as well as genotoxic and epigenetic effects in workers other than healthcare workers. Furthermore, gaps in the current knowledge regarding the potential epigenetic effects caused by antineoplastic drug exposure and regarding the link between internal antineoplastic drug concentration and genotoxic and epigenetic effects after occupational exposure to antineoplastic agents were identified, offering a first step for future research.

Association between metal exposure from e-cigarette components and toxicity endpoints: A literature review.

Electronic cigarette is often promoted and perceived as an 'healthy' alternative compared to conventional cigarettes. However, growing body of evidence indicate the possible adverse health effect associated with e-cigarette. Here we reviewed the literature with a focus on metal exposure in relation to e-cigarette use and related toxicity endpoints. Twenty-nine studies were identified for full text screening after applying the screening criteria of which 5 in vitro studies and 11 epidemiological studies were included for data extraction. Cr, Cu, Ni, Sn are the most found metal in all studies. In vitro, metal from e-cigarette (liquid or aerosols) induced cytotoxicity, oxidative stress, genotoxicity and pro-inflammatory responses. It was observed that the presence of nicotine can influence metal-induced in vitro toxicity. Based on epidemiological studies, the metal burden in e-cigarette users showed to be elevated in different populations (including e.g. NHANES). However, most often such studies were limited by the missing user characteristics, and information of other potential sources of metal exposure. In general, metals from e-cigarette use can be associated with toxicity endpoints but to uncover the metal related hazard of e-cigarette in users, more detailed data on metals in vapors and e-liquids; user habits and user demographics are needed.

Genetic and epigenetic regulation of Catechol-O-methyltransferase in relation to inflammation in chronic fatigue syndrome and Fibromyalgia.

BACKGROUND: Catechol-O-methyltransferase (COMT) has been shown to influence clinical pain, descending modulation, and exercise-induced symptom worsening. COMT regulates nociceptive processing and inflammation, key pathophysiological features of Chronic Fatigue Syndrome and Fibromyalgia (CFS/FM). We aimed to determine the interactions between genetic and epigenetic mechanisms regulating COMT and its influence on inflammatory markers and symptoms in patients with CFS/FM. METHODS: A case-control study with repeated-measures design was used to reduce the chance of false positive and increase the power of our findings. Fifty-four participants (28 patients with CFS/FM and 26 controls) were assessed twice within 4 days. The assessment included clinical questionnaires, neurophysiological assessment (pain thresholds, temporal summation, and conditioned pain modulation), and blood withdrawal in order to assess rs4818, rs4633, and rs4680 COMT polymorphisms and perform haplotype estimation, DNA methylation in the COMT gene (both MB-COMT and S-COMT promoters), and cytokine expression (TNF-α, IFN-γ, IL-6, and TGF-ß). RESULTS: COMT haplotypes were associated with DNA methylation in the S-COMT promoter, TGF-ß expression, and symptoms. However, this was not specific for one condition. Significant between-group differences were found for increased DNA methylation in the MB-COMT promoter and decreased IFN-γ expression in patients. DISCUSSION: Our results are consistent with basic and clinical research, providing interesting insights into genetic-epigenetic regulatory mechanisms. MB-COMT DNA methylation might be an independent factor contributing to the pathophysiology of CFS/FM. Further research on DNA methylation in complex conditions such as CFS/FM is warranted. We recommend future research to employ a repeated-measure design to control for biomarkers variability and within-subject changes.

Exposure to silicates and systemic autoimmune-related outcomes in rodents: a systematic review.

BACKGROUND: Autoimmunity can result from the interplay between genetic background and effects of environmental and/or occupational exposure to hazardous materials. Several compounds, including silica dust, have been linked with systemic autoimmunity and systemic autoimmune diseases, based on epidemiological evidence. For asbestos, a strong link with systemic autoimmune diseases does not yet exist, however, several studies have documented features of autoimmunity following asbestos exposure. Even so, human studies are limited in their ability to identify and examine isolated exposures, making it difficult to demonstrate causation or to assess pathogenic mechanisms. Therefore, this systematic review examines the existing animal evidence regarding autoimmunity and exposure to silicates (silica and asbestos). METHODS: PubMed and EMBASE were systematically searched for peer-reviewed studies examining systemic autoimmune disease-related outcomes after silicate exposure in rodents. Literature databases were searched up to September 2021 for studies written in English and where the full text was available. Search strings were established based on a PECO (Population, Exposure, Comparator, Outcome) format. After title, abstract, and full-text screening, thirty-four studies were identified for further analysis. Quality assessment through ToxR tool and qualitative analysis of the results was performed. RESULTS: Although there was significant heterogeneity in the included studies in terms of exposure protocol and genetic background of the rodent models used, it was noted that both genetic background and exposure to silicates [(crystalline) silica and asbestos] are highly relevant to the development of (sub-) clinical systemic autoimmune disease. CONCLUSION: Parallels were observed between the findings from the animal (this review) and human (epidemiological) studies, arguing that experimental animal models are valuable tools for examining exacerbation or development of autoimmune disease after silicate exposure. However, genetic background and synergism between exposures should be considered in future studies.

Neurotoxicity of four frequently used nanoparticles: a systematic review to reveal the missing data.

Systemic exposure to nanoparticles (NPs) adversely affects different organs, including the nervous system. We systematically extracted data from publication on PubMed and Embase database up to the year 2020, and analyzed in vitro and in vivo neurotoxicity of 4 of the most well studied NPs (silver NPs, carbon-based NPs, iron NPs and silica NPs). A relatively good correlation was observed between in vitro and in vivo effects, including genotoxicity, oxidative stress, apoptosis and pro-inflammatory effects. However, crucial knowledge gap exists in current understanding of the underlying mechanisms. Some of the critical knowledge gaps and research needs identified in relation to neurotoxicity of nanoparticles include (1) lack of physio-chemical characteristics of NPs used, (2) cellular/tissue uptake of NP, (3) NP translocation across the blood-brain barrier (BBB), (4) Effect of exposure routes.

Epigenetic Mechanisms in Understanding Nanomaterial-Induced Toxicity.

The toxic effects of different forms of nanomaterials comprise a series of biological effects such as oxidative stress; DNA damage; inflammatory response; activation of nuclear transcription factors. Some of these are key characteristics of human carcinogens and have been considered for hazard identification of nanomaterials. In addition, epigenetic changes also play a key role in the multi-step sequential process of carcinogenesis. Epigenetic modifications may constitute changes in DNA methylation, histone modifications (methylation, acetylation etc), and changes in non-coding RNA, leading to an altered gene expression profile. In this chapter, we describe the state-of-the-art of epigenetic modifications induced by different nanomaterials, from a limited number of in vitro- in vivo and human studies, a majority of which is primarily focused on DNA methylation. We also highlight the potential challenges and future directions in the field of epigenetics research in nanomaterial toxicology.

From inequitable to sustainable e-waste processing for reduction of impact on human health and the environment.

Recycling of electric and electronic waste products (e-waste) which amounted to more than 50 million metric tonnes per year worldwide is a massive and global operation. Unfortunately, an estimated 70-80% of this waste has not been properly managed because the waste went from developed to low-income countries to be dumped into landfills or informally recycled. Such recycling has been carried out either directly on landfill sites or in small, often family-run recycling shops without much regulations or oversights. The process traditionally involved manual dismantling, cleaning with hazardous solvents, burning and melting on open fires, etc., which would generate a variety of toxic substances and exposure/hazards to applicators, family members, proximate residents and the environment. The situation clearly calls for global responsibility to reduce the impact on human health and the environment, especially in developing countries where poor residents have been shouldering the hazardous burden. On the other hand, formal e-waste recycling has been mainly conducted in small scales in industrialized countries. Whether the latter process would impose less risk to populations and environment has not been determined yet. Therefore, the main objectives of this review are: 1. to address current trends and emerging threats of not only informal but also formal e-waste management practices, and 2. to propose adequate measures and interventions. A major recommendation is to conduct independent surveillance of compliance with e-waste trading and processing according to the Basel Ban Amendment. The recycling industry needs to be carefully evaluated by joint effort from international agencies, producing industries and other stakeholders to develop better processes. Subsequent transition to more sustainable and equitable e-waste management solutions should result in more effective use of natural resources, and in prevention of adverse effects on health and the environment.

Carbon Nanotube- and Asbestos-Induced DNA and RNA Methylation Changes in Bronchial Epithelial Cells.

Carbon nanotubes (CNTs) are nanoscale tube-shaped carbon materials used in many industrial areas. Their fiber shape has caused concerns about their toxicity given their structural similarity with asbestos. The aim here was to elucidate the effect of CNTs and asbestos exposure on global DNA and RNA methylation and the methylation of genes associated with cell cycle, inflammation, and DNA damage processes in human lung cells. Human bronchial epithelial cells (16HBE14o-) were exposed for 24 h to 25 and 100 µg/mL CNTs (single-walled CNTs [SWCNTs] and multiwalled CNTs [MWCNTs]) and 2.5 µg/mL asbestos (chrysotile, amosite, and crocidolite). Global DNA and RNA (hydroxy)methylation to cytosines was measured by a validated liquid chromatography tandem-mass spectrometry method. Global RNA methylation to adenines was measured by a colorimetric ELISA-like assay. Gene-specific DNA methylation status at certain cytosine-phosphate-guanine (CpG) sites of cyclin-dependent kinase inhibitor 1A ( CDKN1A), serine/threonine kinase ( ATM), and TNF receptor-associated factor 2 ( TRAF2) were analyzed by using bisulfite pyrosequencing technology. Only MWCNT-exposed cells showed significant global DNA hypomethylation of cytosine and global RNA hypomethylation of adenosine. SWCNT, MWCNT, and amosite exposure decreased DNA methylation of CDKN1A. ATM methylation was affected by chrysotile, SWCNT, and MWCNT. However, SWCNT exposure led to DNA hypermethylation of TRAF2. These findings contribute to further understanding of the effect of CNTs on different carcinogenic pathways.

Differences in MWCNT- and SWCNT-induced DNA methylation alterations in association with the nuclear deposition.

BACKGROUND: Subtle DNA methylation alterations mediated by carbon nanotubes (CNTs) exposure might contribute to pathogenesis and disease susceptibility. It is known that both multi-walled carbon nanotubes (MWCNTs) and single-walled carbon nanotubes (SWCNTs) interact with nucleus. Such, nuclear-CNT interaction may affect the DNA methylation effects. In order to understand the epigenetic toxicity, in particular DNA methylation alterations, of SWCNTs and short MWCNTs, we performed global/genome-wide, gene-specific DNA methylation and RNA-expression analyses after exposing human bronchial epithelial cells (16HBE14o- cell line). In addition, the presence of CNTs on/in the cell nucleus was evaluated in a label-free way using femtosecond pulsed laser microscopy. RESULTS: Generally, a higher number of SWCNTs, compared to MWCNTs, was deposited at both the cellular and nuclear level after exposure. Nonetheless, both CNT types were in physical contact with the nuclei. While particle type dependency was noticed for the identified genome-wide and gene-specific alterations, no global DNA methylation alteration on 5-methylcytosine (5-mC) sites was observed for both CNTs. After exposure to MWCNTs, 2398 genes were hypomethylated (at gene promoters), and after exposure to SWCNTs, 589 CpG sites (located on 501 genes) were either hypo- (N = 493 CpG sites) or hypermethylated (N = 96 CpG sites). Cells exposed to MWCNTs exhibited a better correlation between gene promoter methylation and gene expression alterations. Differentially methylated and expressed genes induced changes (MWCNTs > SWCNTs) at different cellular pathways, such as p53 signalling, DNA damage repair and cell cycle. On the other hand, SWCNT exposure showed hypermethylation on functionally important genes, such as SKI proto-oncogene (SKI), glutathione S-transferase pi 1 (GTSP1) and shroom family member 2 (SHROOM2) and neurofibromatosis type I (NF1), which the latter is both hypermethylated and downregulated. CONCLUSION: After exposure to both types of CNTs, epigenetic alterations may contribute to toxic or repair response. Moreover, our results suggest that the observed differences in the epigenetic response depend on particle type and differential CNT-nucleus interactions.

Epigenetic effects of carbon nanotubes in human monocytic cells.

Carbon nanotubes (CNTs) are fibrous carbon-based nanomaterials with a potential to cause carcinogenesis in humans. Alterations in DNA methylation on cytosine-phosphate-guanidine (CpG) sites are potential markers of exposure-induced carcinogenesis. This study examined cytotoxicity, genotoxicity and DNA methylation alterations on human monocytic cells (THP-1) after incubation with single-walled CNTs (SWCNTs) and multi-walled CNTs (MWCNTs). Higher cytotoxicity and genotoxicity were observed after incubation with SWCNTs than incubation with MWCNTs. At the selected concentrations (25 and 100 µg/ml), DNA methylation alterations were studied. Liquid chromatography-mass spectrometry (LC-MS/MS) was used to assess global DNA methylation, and Illumina 450K microarrays were used to assess methylation of single CpG sites. Next, we assessed gene promoter-specific methylation levels. We observed no global methylation or hydroxymethylation alterations, but on gene-specific level, distinct clustering of CNT-treated samples were noted. Collectively, CNTs induced gene promoter-specific altered methylation and those 1127 different genes were identified to be hypomethylated. Differentially methylated genes were involved in several signalling cascade pathways, vascular endothelial growth factor and platelet activation pathways. Moreover, possible contribution of the epigenetic alterations to monocyte differentiation and mixed M1/M2 macrophage polarisation were discussed.

Genotoxicity of antiobesity drug orlistat and effect of caffeine intervention: an in vitro study.

CONTEXT: Obesity is a major global health problem associated with various adverse effects. Pharmacological interventions are often necessary for the management of obesity. Orlistat is an FDA-approved antiobesity drug which is a potent inhibitor of intestinal lipases. OBJECTIVE: In the current study, orlistat was evaluated for its genotoxic potential in human lymphocyte cells in vitro and was compared with that of another antiobesity drug sibutramine, presently withdrawn from market due its undesirable health effects. Caffeine intake may be an additional burden in people using anorectic drugs, therefore, further work is needed to be carried out to evaluate the possible effects of caffeine on orlistat-induced DNA damage. MATERIALS AND METHODS: Human lymphocytes were exposed to orlistat (250, 500 and 1000 µg/ml), sibutramine (250, 500 and 1000 µg/ml) and caffeine (25, 50, 75, 100, 125 and 150 µg/ml) to assess their genotoxicity by comet assay in vitro. In addition, lymphocytes were co-incubated with caffeine (50, 75 and 100 µg/ml) and a single concentration of orlistat (250 µg/ml). RESULTS: Orlistat and sibutramine were genotoxic at all concentrations tested, sibutramine being more genotoxic. Caffeine was found to be genotoxic at concentrations 125 µg/ml and above. Co-treatment of orlistat with non-genotoxic concentrations (50, 75 and 100 µg/ml) of caffeine lead to a decrease in DNA damage. DISCUSSION AND CONCLUSION: Orlistat can induce DNA damage in human lymphocytes in vitro and caffeine was found to reduce orlistat-induced genotoxicity.

Antimutagenic and genoprotective effects of Saraca asoca bark extract.

AIM OF THE STUDY: Traditionally herbal formulations have been used effectively for the management of disorders that are now being accepted worldwide. Saraca asoca bark extract (SAE) finds use in traditional herbal medicine. In the present study, SAE were studied for their antioxidant, antimutagenic, and antigenotoxic properties. METHODS: SAE were evaluated for antimutagenic property in Salmonella strains (TA97a, TA98, TA100, and TA102), in the presence and absence of metabolic activation (S9). The SAE was also studied for antigenotoxic property against cyclophosphamide (CP) in Swiss albino male mice in vivo. The extract was analyzed using high-performance liquid chromatography (HPLC). RESULTS: The study reveals antimutagenic property of the bark extract in Salmonella strains in the presence and absence of metabolic activation (S9). The study reports antigenotoxic property of the bark extract against CP in vivo. Thiobarbituric acid reactive species assay on the bark extract revealed antioxidant property. HPLC revealed the presence of two peaks corresponding to gallic acid and (-)-epicatechin, respectively. CONCLUSION: The study clearly reveals the antimutagenic and antigenotoxic properties of SAE.

Sodium fluoride promotes apoptosis by generation of reactive oxygen species in human lymphocytes.

Fluoride generated the attention of toxicologists due to its deleterious effects at high concentrations in human populations suffering from fluorosis and with in vivo experimental models. Interest in its undesirable effects has resurfaced due to the awareness that this element interacts with cellular systems even at low doses. This study focused on examining the adverse effects of inorganic fluoride (NaF) on human lymphocyte cells in vitro. Mitochondrial function, oxidative stress, cell cycle progression, and mode of cell death were combined with genotoxic endpoints. Data demonstrated that NaF at lower concentrations, although not significantly cytotoxic and genotoxic, induced oxidative stress leading to apoptotic cell death. The results also suggested that at low concentrations (<1 µg/ml), NaF may affect cell cycle progression. Taken together, our findings confirm earlier reports on mechanisms involved in NaF-induced apoptosis.

Biosynthesis and safety evaluation of ZnO nanoparticles.

The secrets gleaned from nature have led to the development of biomimetic approaches for the growth of advanced nanomaterials. Biological methods for nanoparticle synthesis using microorganisms, enzymes, and plants or plant extracts have been suggested as possible ecofriendly alternatives to chemical and physical methods. Here, we report extracellular mycosynthesis of ZnO-NPs by Alternaria alternata (Fr.) Keissl (1912). On treating zinc sulfate solution with fungal culture filtrate, rapid reduction of ZnSO4 was observed leading to the formation of highly stable ZnO-NPs in the solution and up-to-date literature survey showed this was the first report of biosynthesis of ZnO-NPs using this fungus. The particles thereby obtained were characterized by different analytical techniques. EDX-spectrum revealed the presence of zinc and oxygen in the nanoparticles. FTIR spectroscopy confirmed the presence of a protein shell outside the nanoparticles which in turn also support their stabilization. DLS and TEM analysis of the ZnO-NPs indicated that they ranged in size from 45 to 150 nm with average size of 75 ± 5 nm. But potential negative impacts of nanomaterials are sometimes overlooked during the discovery phase of research. Therefore, in the present study, bio-safety of mycosynthesized ZnO-NPs were evaluated by using cytotoxicity and genotoxicity assays in human lymphocyte cells, in vitro. Cytotoxicity studied as function of membrane integrity and mitochondrial dehydrogenase activity revealed significant (P < 0.05) toxicity at treatment concentration of 500 µg/ml and above. Additionally, DNA damaging potential was also studied using comet assay. The results revealed significant genotoxicity at the highest concentration (1,000 µg/ml).

Genotoxicity evaluation of 4-carboxyl- 2,6-dinitrophenylazohydroxynaphthalenes in mice.

A short-term in vivo genotoxicity evaluation of 4-carboxyl-2,6-dinitrophenylazohydronaphthalenes (AZ-01 to AZ-04) has been carried out in mice. Aqueous colloidal solutions of the dyes were administered to mice on each day for 5 successive days using gastric gavages. Two end point assessments of the genotoxicity potentials of the dyes were assessed using comet assay and chromosomal aberration studies using the mice bone marrow cells. The dyes were well tolerated at the doses investigated, as there were no deaths or any adverse pharmacotoxic events. Dose-dependent DNA damage (in terms of percentage of tail DNA and Olive tail moment) occurred with AZ-01 and AZ-02, although the effects were significant only with the highest doses. AZ-03 gave similar patterns with those of AZ-01 and AZ-02, while replacement with butanone in AZ-04 altered the observed pattern. Minimal chromosomal damages were obtained for the four dyes, with AZ-01 and AZ-02 giving nonsignificant damages, while the highest dose of AZ-03 produced significant aberrations in terms of breaks. Some minor isochromatid breaks and gaps were also noticed in the dye-treated mice. Mitotic indices in all cases were not significantly different from concomitantly administered vehicle control showing lack of cytotoxicity of the monoazo dyes at these doses. The monoazo dyes show the potential of being utilized as colorants, pending further required tests.

Effects of exposure to environmental factors on obesity-related growth parameters and leptin (LEP) methylation in children.

The prevalence of childhood obesity is rapidly increasing. Therefore, gaining more information on the role of environmental parameters is key. With overexpression of leptin (encoded by LEP) in obesity, LEP methylation might be altered by environmental exposures. This study aims to assess effects of ambient air pollution and nearby greenness on obesity-related growth and LEP methylation in early childhood. We monitored 120 mother-child pairs from conception until the age of five. Buccal swabs and anthropometric measurements of the children were taken at six months, one year, and five years old. Buccal DNA was extracted to determine LEP methylation levels. Estimates of air pollution and nearby greenness were calculated using high-resolution models. Effects of air pollution and nearby greenness on growth or LEP methylation were investigated using linear mixed effects models. Positive associations were shown for air pollution between conception and age one on impedance in six-month-olds and one-year-olds in the crude model. PM with aerodynamic diameter ≤10 (PM10) and ≤2.5 µm (PM2.5) positively associated with waist-hip-ratio and waist circumference at age five in the fully adjusted model. In early childhood, closest distance to forest negatively, and urban green and forest positively associated with weight-for-length, body mass index, and fat percentage in five-year-olds in the fully adjusted model. No significant associations for noise, and walkability on growth were seen. Negative associations were shown for smaller green clusters and positive associations for greater green clusters on LEP methylation in one-year-olds. For forest distance, walkability, noise, or all green on LEP methylation, no significant associations were found. Evidence is provided that ambient air pollution might have a significant effect on impedance and waist-hip-ratio, suggesting an increased risk of childhood obesity. Based on LEP methylation, greater green clusters might associate with a decreased risk of childhood obesity, while smaller green clusters showed the opposite.