Biomechanical effects of environmental and engineered particles on human airway smooth muscle cells

The Cultivation Modality and Barrier Maturity Modulate the Toxicity of Industrial Zinc Oxide and Titanium Dioxide Nanoparticles on Nasal, Buccal, Bronchial, and Alveolar Mucosa Cell-Derived Barrier Models

As common industrial by-products, airborne engineered nanomaterials are considered important environmental toxins to monitor due to their potential health risks to humans and animals. The main uptake routes of airborne nanoparticles are nasal and/or oral inhalation, which are known to enable the transfer of nanomaterials into the bloodstream resulting in the rapid distribution throughout the human body. Consequently, mucosal barriers present in the nose, buccal, and lung have been identified and intensively studied as the key tissue barrier to nanoparticle translocation. Despite decades of research, surprisingly little is known about the differences among various mucosa tissue types to tolerate nanoparticle exposures. One limitation in comparing nanotoxicological data sets can be linked to a lack of harmonization and standardization of cell-based assays, where (a) different cultivation conditions such as an air-liquid interface or submerged cultures, (b) varying barrier maturity, and (c) diverse media substitutes have been used. The current comparative nanotoxicological study, therefore, aims at analyzing the toxic effects of nanomaterials on four human mucosa barrier models including nasal (RPMI2650), buccal (TR146), alveolar (A549), and bronchial (Calu-3) mucosal cell lines to better understand the modulating effects of tissue maturity, cultivation conditions, and tissue type using standard transwell cultivations at liquid-liquid and air-liquid interfaces. Overall, cell size, confluency, tight junction localization, and cell viability as well as barrier formation using 50% and 100% confluency was monitored using trans-epithelial-electrical resistance (TEER) measurements and resazurin-based Presto Blue assays of immature (e.g., 5 days) and mature (e.g., 22 days) cultures in the presence and absence of corticosteroids such as hydrocortisone. Results of our study show that cellular viability in response to increasing nanoparticle exposure scenarios is highly compound and cell-type specific (TR146 6 ± 0.7% at 2 mM ZnO (ZnO) vs. ~90% at 2 mM TiO2 (TiO2) for 24 h; Calu3 93.9 ± 4.21% at 2 mM ZnO vs. ~100% at 2 mM TiO2). Nanoparticle-induced cytotoxic effects under air-liquid cultivation conditions declined in RPMI2650, A549, TR146, and Calu-3 cells (~0.7 to ~0.2-fold), with increasing 50 to 100% barrier maturity under the influence of ZnO (2 mM). Cell viability in early and late mucosa barriers where hardly influenced by TiO2 as well as most cell types did not fall below 77% viability when added to Individual ALI cultures. Fully maturated bronchial mucosal cell barrier models cultivated under ALI conditions showed less tolerance to acute ZnO nanoparticle exposures (~50% remaining viability at 2 mM ZnO for 24 h) than the similarly treated but more robust nasal (~74%), buccal (~73%), and alveolar (~82%) cell-based models.

Effects of differently incubated cupric oxide nanoparticles on the granulosa cells of caprine ovary in vitro

In the nanoscience metal and metal oxide, nanoparticles have a prominent place because of their vast applications. Recent finding shows that in addition to size, there are other critical factors governing the biological response of nanoparticles. These factors include surface chemistry and shape that influences solubility, rate of diffusion, drug delivery, melting temperature, and colour of the nanoparticles. It is thus the present study that was aimed to investigate the effect of temperature on the shape and size of nanoparticles and related cytotoxicity of these particles on ovarian granulosa cells. Cupric oxide nanoparticles (CuONPs) were synthesized using a simple, efficient, and reproducible precipitation method involving the reduction of Cu metal salt with sodium hydroxide and then incubation of the precipitates at 70 °C for 5 h. Subsequently, this prepared sample was divided into 3 subsamples and incubated at 3 different temperatures, i.e. 70 °C, 150 °C, and 350 °C for 5 h to study the effect of temperature on the particles. The products were characterized by XRD, FTIR, HRTEM, and FESEM. Characterization of the particles revealed that all particles were monoclinic crystalline in nature and had a size range from 9 to 60 nm. Particles were of different shapes: spherical, needle, and capsule. The toxicity of each particle was determined on granulosa cells by exposing cells for 24 h at 2 different doses. Toxicological results showed the size and shape-related toxicity of nanoparticles where spherical shapes were significantly more toxic than capsule-shaped particles.

Hazard index of microplastics contamination in various fishes collected off Parangipettai, Southeast coast of India

The authors of the present research aimed to assess microplastics (MPs) contamination in the gills and gut of selected fishes from various aquatic zones and also to bring out the risks of the identified polymers. Accordingly, about 200 fish specimens of 10 different species were collected from the landing center at Parangipettai, southeast coast of India. The fishes were dissected to investigate MPs contamination in their gills and gut. The dissected tissues were acid digested and filtered to observe its microplastic contamination using a stereozoom microscope. In gills, Cynoglossus arel had the least contamination (0.4 ± 0.01 particles/ind) and Mugil cephalus had highest microplastic contamination (1.7 ± 0.01 particles/ind). In gut, C. arel had the minimum contamination (0.7 ± 0.09 particles/ind) and Rastrelliger kanagurta had maximum contamination (2.3 ± 0.26 particles/ind). The size of microplastics isolated from the present study ranged from 100 to 1000 μm. Among microplastic shapes, fibers (97%) and pellets (3%) were observed. About eight colours of microplastics were observed in the fishes among which black was dominant. Three polymers such as LDPE, PP and PS were identified by μFTIR, among which LDPE (57%) was dominant. Polymer Hazard Index denotes that LDPE (6.27), PP (3.4) and PS (2.7) have a PHI score of 1-10 classifying them in the hazard category II which has a medium risk. These polymers may directly enter the human body when consumed and cause health implications which require further investigation.

Dynamics of airborne microplastics, appraisal and distributional behaviour in atmosphere; a review

The use of plastics is common across all aspects of human life owing to its durable and versatile nature. The generation and utilization of plastics are directly related to the anthropogenic activities. The extensive use of plastics and adoption of inappropriate waste-management frameworks has resulted in their release into the environment, where they may persist. Different environmental factors, such as, photochemical, thermo-oxidation, and biological degradation, can lead to the degradation of plastics into micro- (MPs) and nano-plastics (NPs). The behaviour and concentration of MPs in the terrestrial environment can depend on their size, density, and local atmospheric conditions. Microplastics and nanoplastics may enter the food web, carrying various organic pollutants, which bio-accumulate at different trophic levels, prompting organism health concerns. Microplastics being airborne identifies as new exposure route. Dietary and airborne exposure to MPs has led researchers to stress the importance of evaluating their toxicological potential. The primary goal of this paper is to explore the environmental fate of MPs from sources to sink in the terrestrial environment, as well as detail their potential impacts on human health. Additionally, this review article focuses on the presence of airborne microplastics, detailed sample pre-processing methods, and outlines analytical methods for their characterization.

In vitro copper oxide nanoparticle toxicity on intestinal barrier

The use of CuO nanoparticles (NPs) has increased greatly and their potential effects on human health need to be investigated. Differentiated Caco-2 cells were treated from the apical (Ap) and the basolateral (Bl) compartment with different concentrations (0, 10, 50 and 100 μg/mL) of commercial or sonochemically synthesized (sono) CuO NPs. Sono NPs were prepared in ethanol (CuOe) or in water (CuOw), obtaining CuO NPs differing in size and shape. The effects on the Caco-2 cell barrier were assessed via transepithelial electrical resistance (TEER) evaluation just before and after 1, 2 and 24 hours of exposure and through the analysis of cytokine release and biomarkers of oxidative damage to proteins after 24 hours. Sono CuOe and CuOw NPs induced a TEER decrease with a dose-dependent pattern after Bl exposure. Conversely, TEER values were not affected by the Ap exposure to commercial CuO NPs and, concerning the Bl exposure, only the lowest concentration tested (10 μg/mL) caused a TEER decrease after 24 hours of exposure. An increased release of interleukin-8 was induced by sono CuO NPs after the Ap exposure to 100 μg/mL and by sono and commercial CuO after the Bl exposure to all the concentrations. No effects of commercial and sono CuO NPs on interleukin-6 (with the only exception of 100 μg/mL Bl commercial CuO) and tumor necrosis factor-α release were observed. Ap treatment with commercial and CuOw NPs was able to induce significant alterations on specific biomarkers of protein oxidative damage (protein sulfhydryl group oxidation and protein carbonylation).

Toxicity of copper oxide nanoparticles: a review study

Copper oxide nanoparticles (CuO NPs) use has exponentially increased in various applications (such as industrial catalyst, gas sensors, electronic materials, biomedicines, environmental remediation) due to their flexible properties, i.e. large surface area to volume ratio. These broad applications, however, have increased human exposure and thus the potential risk related to their short- and long-term toxicity. Their release in environment has drawn considerable attention which has become an eminent area of research and development. To understand the toxicological impact of CuO NPs, this review summarises the in-vitro and in-vivo toxicity of CuO NPs subjected to species (bacterial, algae, fish, rats, human cell lines) used for toxicological hazard assessment. The key factors that influence the toxicity of CuO NPs such as particle shape, size, surface functionalisation, time-dose interaction and animal and cell models are elaborated. The literature evidences that the CuO NPs exposure to the living systems results in reactive oxygen species generation, oxidative stress, inflammation, cytotoxicity, genotoxicity and immunotoxicity. However, the physio-chemical characteristics of CuO NPs, concentration, mode of exposure, animal model and assessment characteristics are the main perspectives that define toxicology of CuO NPs.

Global distribution of microplastics and its impact on marine environment-a review

Microplastics are the major environmental health hazards spotted in almost all the marine habitats and biota of world. The earlier research on microplastics have mainly focused on studying abundance and distribution as well as impacts on organisms, while the existing review articles have reviewed on any one of the above aspects or the environmental fate of microplastics. The current review focuses on all the above facets thereby bringing out the incompleteness in information globally in the respective facets. Our findings suggest that among 192 countries of the world, only 22.9% (44) of the countries have carried out research regarding microplastics, while impacts on organisms have mostly targeted fish (38%), whereas studies on other highly affected organisms such as turtles (1%) are not well documented. Therefore, we suggest expanding research in all the above aspects of microplastics considering that there are several pristine marine environments and organisms that are yet unexplored. Quantifying research in these regards would enable to propose a microplastic threshold level and formulate control measures to reduce the use of plastics and its subsequent threat to the marine environment.

Metal nanomaterials: Immune effects and implications of physicochemical properties on sensitization, elicitation, and exacerbation of allergic disease

The recent surge in incorporation of metallic and metal oxide nanomaterials into consumer products and their corresponding use in occupational settings have raised concerns over the potential for metals to induce size-specific adverse toxicological effects. Although nano-metals have been shown to induce greater lung injury and inflammation than their larger metal counterparts, their size-related effects on the immune system and allergic disease remain largely unknown. This knowledge gap is particularly concerning since metals are historically recognized as common inducers of allergic contact dermatitis, occupational asthma, and allergic adjuvancy. The investigation into the potential for adverse immune effects following exposure to metal nanomaterials is becoming an area of scientific interest since these characteristically lightweight materials are easily aerosolized and inhaled, and their small size may allow for penetration of the skin, which may promote unique size-specific immune effects with implications for allergic disease. Additionally, alterations in physicochemical properties of metals in the nano-scale greatly influence their interactions with components of biological systems, potentially leading to implications for inducing or exacerbating allergic disease. Although some research has been directed toward addressing these concerns, many aspects of metal nanomaterial-induced immune effects remain unclear. Overall, more scientific knowledge exists in regards to the potential for metal nanomaterials to exacerbate allergic disease than to their potential to induce allergic disease. Furthermore, effects of metal nanomaterial exposure on respiratory allergy have been more thoroughly-characterized than their potential influence on dermal allergy. Current knowledge regarding metal nanomaterials and their potential to induce/exacerbate dermal and respiratory allergy are summarized in this review. In addition, an examination of several remaining knowledge gaps and considerations for future studies is provided.

Biological impact of nanodiamond particles - label free, high-resolution methods for nanotoxicity assessment

Current methods for the assessment of nanoparticle safety that are based on 2D cell culture models and fluorescence-based assays show limited sensitivity and they lack biomimicry. Consequently, the health risks associated with the use of many nanoparticles have not yet been established. There is a need to develop in vitro models that mimic physiology more accurately and enable high throughput assessment. There is also a need to set up new assays that offer high sensitivity and are label-free. Here we developed 'mini-liver' models using scaffold-free bioprinting and used these models together with label-free nanoscale techniques for the assessment of toxicity of nanodiamond produced by laser-assisted technology. Results showed that NDs induced cytotoxicity in a concentration and exposure-time dependent manner. The loss of cell function was confirmed by increased cell stiffness, decreased cell membrane barrier integrity and reduced cells mobility. We further showed that NDs elevated the production of reactive oxygen species and reduced cell viability. Our approach that combined mini-liver models with label-free high-resolution techniques showed improved sensitivity in toxicity assessment. Notably, this approach allowed for label-free semi-high throughput measurements of nanoparticle-cell interactions, thus could be considered as a complementary approach to currently used methods.

Biodistribution and toxickinetic variances of chemical and green Copper oxide nanoparticles in vitro and in vivo

In this study, chemical (S1) and green (S2) Copper Oxide nanoparticles (NPs) were synthesized to determine their biodistribution and toxicokinetic variances in vitro and in vivo. Both NPs significantly released Copper ions (Cu) in lymphocytes and were primarily deposited in the mononuclear phagocyte system (MPS) such as the liver and spleen in mice. In particular, S2NPs seemed to be prominently stored in the spleen, whereas the S1NPs were widely stored in more organs including the liver, heart, lungs, kidney and intestine. The circulation in the blood and fecal excretions both showed higher S2NPs contents respectively. Measurements of cell viability, Hemolysis assay, Reactive Oxygen Species (ROS) generation, biochemical estimation and apoptotic or necrotic study in lymphocytes after 24 h and measurements of body and organ weight, serum chemistry evaluation, cytokines level, protein expressions and histopathology of Balb/C mice after 15 days indicated significant toxicity difference between the S1NPs and S2NPs. Our observations proved that the NPs physiochemical properties influence toxicity and Biodistribution profiles in vitro and in vivo.

Contractility of Airway Smooth Muscle Cell in Response to Zinc Oxide Nanoparticles by Traction Force Microscopy

Zinc oxide nanoparticles (ZnO-NPs) have been widely used in engineering and biomedicine. However, their adverse pathological effects and mechanisms, especially the biomechanical effects on respiratory system where airway smooth muscle cell (ASMC) contractility regulates the airway response and lung function, are not fully understood. Herein, we used traction force microscopy (TFM) method to investigate whether ZnO-NPs of different concentrations (0.1-10 μg/mL) can alter ASMC contractility (basal and agonist-stimulated) after a short-term exposure and the potential mechanisms. We found that ZnO-NPs exposure led to a decrease of ASMC viability in a dose-dependent manner. Notably, basal contractility was enhanced when the concentration of ZnO-NPs was less than 0.1 μg/mL and decreased afterwards, while KCl-stimulated contractility was reduced in all cases of ZnO-NPs treated groups. Cytoskeleton structure was also found to be significantly altered in ASMC with the stimulation of ZnO-NPs. More importantly, it seems that ZnO-NPs with low concentration (< 0.1 μg/mL) would change ASMC contractility without any apparent cytotoxicity through disruption of the microtubule assembly. Moreover, our results also emerged that ASMC contractility responses were regulated by clathrin-mediated endocytosis and cytoskeleton remodeling. Together, these findings indicate the susceptibility of cell mechanics to NPs exposure, suggesting that cell mechanical testing will contribute to uncover the pathological mechanisms of NPs in respiratory diseases.

Nanoparticle-Cell Interaction: A Cell Mechanics Perspective

Progress in the field of nanoparticles has enabled the rapid development of multiple products and technologies; however, some nanoparticles can pose both a threat to the environment and human health. To enable their safe implementation, a comprehensive knowledge of nanoparticles and their biological interactions is needed. In vitro and in vivo toxicity tests have been considered the gold standard to evaluate nanoparticle safety, but it is becoming necessary to understand the impact of nanosystems on cell mechanics. Here, the interaction between particles and cells, from the point of view of cell mechanics (i.e., bionanomechanics), is highlighted and put in perspective. Specifically, the ability of intracellular and extracellular nanoparticles to impair cell adhesion, cytoskeletal organization, stiffness, and migration are discussed. Furthermore, the development of cutting-edge, nanotechnology-driven tools based on the use of particles allowing the determination of cell mechanics is emphasized. These include traction force microscopy, colloidal probe atomic force microscopy, optical tweezers, magnetic manipulation, and particle tracking microrheology.

Evidence of size-dependent effect of silica micro- and nano-particles on basal and specialized monocyte functions

Aim: To analyze the effect of silica particles on monocyte/macrophage functions. Materials & methods: Silica micro- and nanoparticles were obtained by the Stöber method. Their effect on monocyte/macrophage proliferation, activation, membrane integrity and metabolic activity were determined. Results: Silica particles inhibit cell proliferation while 10 nm nanoparticles (NPs) did not affect it. Similarly, silica particles induced strong cell activation. However, 10 nm NPs do not alter IL-12 or nitrite levels. Furthermore, bigger NPs and microparticles increase cell membrane damage and reduce the number of living cells but smallest NPs (10 and 240 nm) did not. Conclusion: Cell activation properties of silica particles could be useful tools for immune stimulation therapy, while 10 nm NPs would be suitable for molecule transportation.

Mechanistic insight into the impact of nanomaterials on asthma and allergic airway disease

Asthma is a chronic respiratory disease known for its high susceptibility to environmental exposure. Inadvertent inhalation of engineered or incidental nanomaterials is a concern for human health, particularly for those with underlying disease susceptibility. In this review we provide a comprehensive analysis of those studies focussed on safety assessment of different nanomaterials and their unique characteristics on asthma and allergic airway disease. These include in vivo and in vitro approaches as well as human and population studies. The weight of evidence presented supports a modifying role for nanomaterial exposure on established asthma as well as the development of the condition. Due to the variability in modelling approaches, nanomaterial characterisation and endpoints used for assessment in these studies, there is insufficient information for how one may assign relative hazard potential to individual nanoscale properties. New developments including the adoption of standardised models and focussed in vitro and in silico approaches have the potential to more reliably identify properties of concern through comparative analysis across robust and select testing systems. Importantly, key to refinement and choice of the most appropriate testing systems is a more complete understanding of how these materials may influence disease at the cellular and molecular level. Detailed mechanistic insight also brings with it opportunities to build important population and exposure susceptibilities into models. Ultimately, such approaches have the potential to more clearly extrapolate relevant toxicological information, which can be used to improve nanomaterial safety assessment for human disease susceptibility.

Comparison between micro- and nanosized copper oxide and water soluble copper chloride: interrelationship between intracellular copper concentrations, oxidative stress and DNA damage response in human lung cells

BACKGROUND

Nano- and microscale copper oxide particles (CuO NP, CuO MP) are applied for manifold purposes, enhancing exposure and thus the potential risk of adverse health effects. Based on the pronounced in vitro cytotoxicity of CuO NP, systematic investigations on the mode of action are required. Therefore, the impact of CuO NP, CuO MP and CuCl2 on the DNA damage response on transcriptional level was investigated by quantitative gene expression profiling via high-throughput RT-qPCR. Cytotoxicity, copper uptake and the impact on the oxidative stress response, cell cycle regulation and apoptosis were further analysed on the functional level.

RESULTS

Cytotoxicity of CuO NP was more pronounced when compared to CuO MP and CuCl2 in human bronchial epithelial BEAS-2B cells. Uptake studies revealed an intracellular copper overload in the soluble fractions of both cytoplasm and nucleus, reaching up to millimolar concentrations in case of CuO NP and considerably lower levels in case of CuO MP and CuCl2. Moreover, CuCl2 caused copper accumulation in the nucleus only at cytotoxic concentrations. Gene expression analysis in BEAS-2B and A549 cells revealed a strong induction of uptake-related metallothionein genes, oxidative stress-sensitive and pro-inflammatory genes, anti-oxidative defense-associated genes as well as those coding for the cell cycle inhibitor p21 and the pro-apoptotic Noxa and DR5. While DNA damage inducible genes were activated, genes coding for distinct DNA repair factors were down-regulated. Modulation of gene expression was most pronounced in case of CuO NP as compared to CuO MP and CuCl2 and more distinct in BEAS-2B cells. GSH depletion and activation of Nrf2 in HeLa S3 cells confirmed oxidative stress induction, mainly restricted to CuO NP. Also, cell cycle arrest and apoptosis induction were most distinct for CuO NP.

CONCLUSIONS

The high cytotoxicity and marked impact on gene expression by CuO NP can be ascribed to the strong intracellular copper ion release, with subsequent copper accumulation in the cytoplasm and the nucleus. Modulation of gene expression by CuO NP appeared to be primarily oxidative stress-related and was more pronounced in redox-sensitive BEAS-2B cells. Regarding CuCl2, relevant modulations of gene expression were restricted to cytotoxic concentrations provoking impaired copper homoeostasis.

Interfacing 3D magnetic twisting cytometry with confocal fluorescence microscopy to image force responses in living cells

Cells and tissues can undergo a variety of biological and structural changes in response to mechanical forces. Only a few existing techniques are available for quantification of structural changes at high resolution in response to forces applied along different directions. 3D-magnetic twisting cytometry (3D-MTC) is a technique for applying local mechanical stresses to living cells. Here we describe a protocol for interfacing 3D-MTC with confocal fluorescence microscopy. In 3D-MTC, ferromagnetic beads are bound to the cell surface via surface receptors, followed by their magnetization in any desired direction. A magnetic twisting field in a different direction is then applied to generate rotational shear stresses in any desired direction. This protocol describes how to combine magnetic-field-induced mechanical stimulation with confocal fluorescence microscopy and provides an optional extension for super-resolution imaging using stimulated emission depletion (STED) nanoscopy. This technology allows for rapid real-time acquisition of a living cell's mechanical responses to forces via specific receptors and for quantifying structural and biochemical changes in the same cell using confocal fluorescence microscopy or STED. The integrated 3D-MTC-microscopy platform takes ∼20 d to construct, and the experimental procedures require ∼4 d when carried out by a life sciences graduate student.

Bioabsorbable zinc ion induced biphasic cellular responses in vascular smooth muscle cells

Bioabsorbable metal zinc (Zn) is a promising new generation of implantable scaffold for cardiovascular and orthopedic applications. In cardiovascular stent applications, zinc ion (Zn²⁺) will be gradually released into the surrounding vascular tissues from such Zn-containing scaffolds after implantation. However, the interactions between vascular cells and Zn²⁺ are still largely unknown. We explored the short-term effects of extracellular Zn²⁺ on human smooth muscle cells (SMCs) up to 24 h, and an interesting biphasic effect of Zn²⁺ was observed. Lower concentrations (<80 μM) of Zn²⁺ had no adverse effects on cell viability but promoted cell adhesion, cell spreading, cell proliferation, cell migration, and enhanced the expression of F-actin and vinculin. Cells treated with such lower concentrations of Zn²⁺ displayed an elongated shape compared to controls without any treatment. In contrast, cells treated with higher Zn²⁺ concentrations (80–120 μM) had opposite cellular responses and behaviors. Gene expression profiles revealed that the most affected functional genes were related to angiogenesis, inflammation, cell adhesion, vessel tone, and platelet aggregation. Results indicated that Zn has interesting concentration-dependent biphasic effects on SMCs with low concentrations being beneficial to cellular functions.

Evaluation of cytotoxicity, morphological alterations and oxidative stress in Chinook salmon cells exposed to copper oxide nanoparticles

The current study is aimed to study cytotoxicity and oxidative stress mediated changes induced by copper oxide nanoparticles (CuO NPs) in Chinook salmon cells (CHSE-214). To this end, a number of biochemical responses are evaluated in CHSE-214 cells which are as follows [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] MTT, neutral red uptake (NRU), lactate dehydrogenase (LDH), protein carbonyl (PC), lipid peroxidation (LPO), oxidised glutathione (GSSG), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione sulfo-transferase (GST), superoxide dismutase (SOD), catalase (CAT), 8-Hydroxy-2'-deoxyguanosine (8-OHdG) and reactive oxygen species (ROS), respectively. The 50% inhibition concentration (IC50) of CuO NPs to CHSE-214 cells after 24 h exposure was found to be 19.026 μg ml(-1). Viability of cells was reduced by CuO NPs, and the decrease was dose dependent as revealed by the MTT and NRU assay. CHSE-214 cells exposed to CuO NPs induced morphological changes. Initially, cells started to detach from the surface (12 h), followed by polyhedric, fusiform appearance (19 h) and finally the cells started to shrink. Later, the cells started losing their cellular contents leading to their death only after 24 h. LDH, PC, LPO, GSH, GPx, GST, SOD, CAT, 8-OHdG and ROS responses were seen significantly increased with the increase in the concentration of CuO NPs when compared to their respective controls. However, significant decrease in GSSG was perceptible in CHSE-214 cells exposed to CuO NPs in a dose-dependent manner. Our data demonstrated that CuO NPs induced cytotoxicity in CHSE-214 cells through the mediation of oxidative stress. The current study provides a baseline for the CuO NPs-mediated cytotoxic assessment in CHSE-214 cells for the future studies.

Human bronchial epithelial cells exposed in vitro to diesel exhaust particles exhibit alterations in cell rheology and cytotoxicity associated with decrease in antioxidant defenses and imbalance in pro- and anti-apoptotic gene expression

Diesel exhaust particles (DEPs) from diesel engines produce adverse alterations in cells of the airways by activating intracellular signaling pathways and apoptotic gene overexpression, and also by influencing metabolism and cytoskeleton changes. This study used human bronchial epithelium cells (BEAS-2B) in culture and evaluates their exposure to DEPs (15ug/mL for 1 and 2 h) in order to determine changes to cell rheology (viscoelasticity) and gene expression of the enzymes involved in oxidative stress, apoptosis, and cytotoxicity. BEAS-2B cells exposed to DEPs were found to have a significant loss in stiffness, membrane stability, and mitochondrial activity. The genes involved in apoptosis [B cell lymphoma 2 (BCL-2 and caspase-3)] presented inversely proportional expressions (p = 0.05, p = 0.01, respectively), low expression of the genes involved in antioxidant responses [SOD1 (superoxide dismutase 1); SOD2 (superoxide dismutase 2), and GPx (glutathione peroxidase) (p = 0.01)], along with an increase in cytochrome P450, family 1, subfamily A, polypeptide 1 (CYP1A1) (p = 0.01). These results suggest that alterations in cell rheology and cytotoxicity could be associated with oxidative stress and imbalance between pro- and anti-apoptotic genes.

In vitro toxicity, apoptosis and antimicrobial effects of phyto-mediated copper oxide nanoparticles

Herein, copper oxide nanoparticles (CuONPs) are proposed for widespread use in emerging biomedical applications.

Assessment of cytotoxicity and oxidative stress induced by titanium oxide nanoparticles on Chinook salmon cells

Titanium oxide nanoparticles (TiO2 NPs) have received wide attention in diverse application, but the potential impact of these nanomaterials on the environment, aquatic life and especially on fish cell lines is lacking. The present study aimed to investigate the cytotoxicity and oxidative stress induced by TiO2 NPs on Chinook salmon cells derived from Oncorhynchus tshawytscha embryos (CHSE-214). The The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide] and neutral red (NR) assays in CHSE-214 cells exposed to TiO2 NPs revealed concentration-dependent cytotoxic effect in the range of 10 to 60 μg/ml for 24 h. CHSE-214 cells exposed to TiO2 NPs (10-60 μg/ml) exhibited significant decline in superoxide dismutase (SOD), catalase (CAT) glutathione (GSH) content and increased lipid peroxidation (LPO) in a concentration-dependent manner. TiO2 NPs induced cytotoxicity and oxidative stress in CHSE-214 cells which serve as a base line studies for future studies.

Assessing the impact of engineered nanoparticles on wound healing using a novel in vitro bioassay

AIM

As engineered nanoparticles (ENPs) increasingly enter consumer products, humans become increasingly exposed. The first line of defense against ENPs is the epithelium, the integrity of which can be compromised by wounds induced by trauma, infection, or surgery, but the implications of ENPs on wound healing are poorly understood.

MATERIALS & METHODS

Herein, we developed an in vitro assay to assess the impact of ENPs on the wound healing of cells from human cornea.

RESULTS & DISCUSSION

We show that industrially relevant ENPs impeded wound healing and cellular migration in a manner dependent on the composition, dose and size of the ENPs as well as cell type. CuO and ZnO ENPs impeded both viability and wound healing for both fibroblasts and epithelial cells. Carboxylated polystyrene ENPs retarded wound healing of corneal fibroblasts without affecting viability.

CONCLUSION

Our results highlight the impact of ENPs on cellular wound healing and provide useful tools for studying the physiological impact of ENPs.

Enriched inorganic compounds in diesel exhaust particles induce mitogen-activated protein kinase activation, cytoskeleton instability, and cytotoxicity in human bronchial epithelial cells

This study assessed the effects of the diesel exhaust particles on ERK and JNK MAPKs activation, cell rheology (viscoelasticity), and cytotoxicity in bronchial epithelial airway cells (BEAS-2B). Crude DEP and DEP after extraction with hexane (DEP/HEX) were utilized. The partial reduction of some DEP/HEX organics increased the biodisponibility of many metallic elements. JNK and ERK were activated simultaneously by crude DEP with no alterations in viscoelasticity of the cells. Mitochondrial activity, however, revealed a decrease through the MTT assay. DEP/HEX treatment increased viscoelasticity and cytotoxicity (membrane damage), and also activated JNK. Our data suggest that the greater bioavailability of metals could be involved in JNK activation and, consequently, in the reduction of fiber coherence and increase in the viscoelasticity and cytotoxicity of BEAS cells. The adverse findings detected after exposure to crude DEP and to DEP/HEX reflect the toxic potential of diesel compounds. Considering the fact that the cells of the respiratory epithelium are the first line of defense between the body and the environment, our data contribute to a better understanding of the pathways leading to respiratory cell injury and provide evidence for the onset of or worsening of respiratory diseases caused by inorganic compounds present in DEP.

SILAC-based quantitative proteomic analysis of human lung cell response to copper oxide nanoparticles

Copper (II) oxide (CuO) nanoparticles (NP) are widely used in industry and medicine. In our study we evaluated the response of BEAS-2B human lung cells to CuO NP, using Stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics and phosphoproteomics. Pathway modeling of the protein differential expression showed that CuO NP affect proteins relevant in cellular function and maintenance, protein synthesis, cell death and survival, cell cycle and cell morphology. Some of the signaling pathways represented by BEAS-2B proteins responsive to the NP included mTOR signaling, protein ubiquitination pathway, actin cytoskeleton signaling and epithelial adherens junction signaling. Follow-up experiments showed that CuO NP altered actin cytoskeleton, protein phosphorylation and protein ubiquitination level.

Cytotoxicity and genotoxicity of nano - and microparticulate copper oxide: role of solubility and intracellular bioavailability

Background

Nano- or microscale copper oxide particles (CuO NP, CuO MP) are increasingly applied as catalysts or antimicrobial additives. This increases the risk of adverse health effects, since copper ions are cytotoxic under overload conditions.

Methods

The extra- and intracellular bioavailability of CuO NP and CuO MP were explored. In addition, different endpoints related to cytotoxicity as well as direct and indirect genotoxicity of the copper oxides and copper chloride (CuCl₂) were compared.

Results

Comprehensively characterized CuO NP and CuO MP were analysed regarding their copper ion release in model fluids. In all media investigated, CuO NP released far more copper ions than CuO MP, with most pronounced dissolution in artificial lysosomal fluid. CuO NP and CuCl₂ caused a pronounced and dose dependent decrease of colony forming ability (CFA) in A549 and HeLa S3 cells, whereas CuO MP exerted no cytotoxicity at concentrations up to 50 μg/mL. Cell death induced by CuO NP was at least in part due to apoptosis, as determined by subdiploid DNA as well as via translocation of the apoptosis inducing factor (AIF) into the cell nucleus. Similarly, only CuO NP induced significant amounts of DNA strand breaks in HeLa S3 cells, whereas all three compounds elevated the level of H₂O₂-induced DNA strand breaks. Finally, all copper compounds diminished the H₂O₂-induced poly(ADP-ribosyl)ation, catalysed predominantly by poly(ADP-ribose)polymerase-1 (PARP-1); here, again, CuO NP exerted the strongest effect. Copper derived from CuO NP, CuO MP and CuCl₂ accumulated in the soluble cytoplasmic and nuclear fractions of A549 cells, yielding similar concentrations in the cytoplasm but highest concentrations in the nucleus in case of CuO NP.

Conclusions

The results support the high cytotoxicity of CuO NP and CuCl₂ and the missing cytotoxicity of CuO MP under the conditions applied. For these differences in cytotoxicity, extracellular copper ion levels due to dissolution of particles as well as differences in physicochemical properties of the particles like surface area may be of major relevance. Regarding direct and indirect genotoxicity, especially the high copper content in the cell nucleus derived after cell treatment with CuO NP appears to be decisive.

Endocytosis of environmental and engineered micro- and nanosized particles

There are many studies with cells to find out how particles interact with them. In contrast to micronsized particles, which are actively taken up by phagocytosis or macropinocytosis, nanosized particles may be taken up by cells through different endocytic pathways or by another, yet to be defined mechanism. There is increasing evidence that it is the nanosized particles, which are a particular risk because of their high content of organic chemicals and their pro-oxidative potential due to the high surface-to-volume ratio of the particles as compared to the bulk material. It is the goal of this article to create an understanding for the interaction of particles with biological systems, with particular consideration of the interaction of nanoparticles (NPs) with lung cells. One is attempting to understand, how NPs interact with cellular membranes, as it is hardly known, how they are taken up by cells, how they are trafficking in cells, and how they interact with subcellular compartments, such as with mitochondria or with the nucleus. Cells tend to defend themselves against any foreign material, which is taken up. In general, they try to eliminate particulate intruders and this is what they usually manage with micronsized particles. However, with NPs it is different. NPs may not be eliminated easily, and, hence may stimulate the cells to react in an unfavorable way. What we can learn is that NPs behave differently than microparticles.

Geographic variation in susceptibility to ventilator-associated pneumonia after traumatic injury

BACKGROUND

Emphasis on prevention of health care-associated infections including ventilator-associated pneumonia (VAP) has increased as hospitals are beginning to be held financially accountable for such infections. Health care-associated infections are often represented as being avoidable; however, the literature indicates that complete preventability may not be possible. The vast majority of research on risk factors for VAP concerns individual-level factors. No studies have investigated the role of the patient's environment before admission. In this study, we aimed to investigate the potential role prehospital environment plays in VAP etiology.

METHODS

In a retrospective cohort study, a sample of 5,031 trauma patients treated with mechanical ventilation between 1996 and 2010 was analyzed to determine the effect of neighborhood on the probability of developing VAP. We evaluated the effect of zip code using multilevel logistic regression analysis adjusting for individual-level factors associated with VAP.

RESULTS

We identified three zip codes with rates of VAP that differed significantly from the mean. Logistic regression indicated that zip code, age, sex, race, injury severity, paralysis, head injury, and number of days on the ventilator were significantly associated with VAP. However, median zip code income was not.

CONCLUSION

Spatial factors that are independent of health care quality may potentiate the likelihood of a patient developing VAP and possibly other types of health care-acquired infections. Unmodifiable environmental patient characteristics may predispose certain populations to developing infections in the setting of trauma.

Asthmatic airway hyperresponsiveness: the ants in the tree

Airways from asthmatics have a propensity to narrow excessively in response to spasmogens (i.e., contractile agonists), a feature called airway hyperresponsiveness (AHR). AHR is an important contributor to asthma symptoms because the degree of responsiveness dictates the amount of airway narrowing that occurs in response to inflammation-derived spasmogens produced endogenously following exposure to environmental triggers, such as allergens, viruses, or pollutants. The smooth muscle encircling the airways is responsible for responsiveness because it constricts the airway lumen when commanded to contract by spasmogens. However, whether AHR seen in asthmatics is due to stronger muscle is equivocal. In this opinion article, I propose that environmental triggers and other inflammatory molecules released during asthma attacks contribute to AHR by increasing muscle force.

A review of mammalian toxicity of ZnO nanoparticles

This review summarizes the literature on mammalian toxicity of ZnO nanoparticles (NPs) published between 2009 and 2011. The toxic effects of ZnO NPs are due to the compound's solubility. Whether the increased intracellular [Zn(2+)] is due to the NPs being taken up by cells or to NP dissolution in medium is still unclear. In vivo airway exposure poses an important hazard. Inhalation or instillation of the NPs results in lung inflammation and systemic toxicity. Reactive oxygen species (ROS) generation likely plays an important role in the inflammatory response. The NPs do not, or only to a minimal extent, cross the skin; this also holds for sunburned skin. Intraperitoneal administration induces neurological effects. The NPs show systemic distribution; target organs are liver, spleen, lung, and kidney and, in some cases, the heart. In vitro exposure of BEAS-2B bronchial epithelial cells and A549 alveolar adenocarcinoma cells results in cytotoxicity, increased oxidative stress, increased intracellular [Ca(2+)], decreased mitochondrial membrane potential, and interleukin (IL)-8 production. Decreased contractility of airway smooth muscle cells poses an additional hazard. In contrast to the results for BEAS-2B and A549 cells, in RKO colon carcinoma cells ZnO NPs and not Zn(2+) induce cytotoxicity and mitochondrial dysfunction. Short-term exposure of skin cells results in apoptosis but not in an inflammatory response, while long-term exposure leads to increased ROS generation, decreased mitochondrial activity, and formation of tubular intercellular structures. Macrophages, monocytes, and dendritic cells are affected; exposure results in cytotoxicity, oxidative stress, intracellular Ca(2+) flux, decreased mitochondrial membrane potential, and production of IL-1β and chemokine CXCL9. The NPs are phagocytosed by macrophages and dissolved in lysosomes. In vitro the Comet assay and the cytokinesis-blocked micronucleus assay show genotoxicity, whereas the Ames test does not. This is, however, not confirmed by in vivo genotoxicity assays. Protein binding results in increased stability.

The developing respiratory tract and its specific needs in regard to ultrafine particulate matter exposure

Nanoparticles have unique physico-chemical properties compared to larger particles that have the potential to provide promising new possibilities for biomedical applications. Considerable research is currently exploring these potentials of nanotechnology. In contrast, airborne particles as components of indoor air, ambient air pollution associated with traffic-related pollution, industry, power plants, and other combustion sources have the potential to harm children's health. However, a similar research effort into the potential health effects of exposure to nanoparticles is lacking. Children differ markedly from adults in their developmental biology rendering young children the most vulnerable group with regard to potentially harmful effects induced by particulate exposure. This review discusses the differences between children and adults in regard to nanoparticle exposure highlighting the uniqueness and vulnerability of children.

Mechanical responsiveness of the endothelial cell of Schlemm's canal: scope, variability and its potential role in controlling aqueous humour outflow

Primary open-angle glaucoma is associated with elevated intraocular pressure, which in turn is believed to result from impaired outflow of aqueous humour. Aqueous humour outflow passes mainly through the trabecular meshwork (TM) and then through pores formed in the endothelium of Schlemm's canal (SC), which experiences a basal-to-apical pressure gradient. This gradient dramatically deforms the SC endothelial cell and potentially contributes to the formation of those pores. However, mechanical properties of the SC cell are poorly defined. Using optical magnetic twisting cytometry and traction force microscopy, here we characterize the mechanical properties of primary cultures of the human SC cell, and for the first time, the scope of their changes in response to pharmacological agents that are known to modulate outflow resistance. Lysophosphatidic acid, sphingosine-1-phosphate (S1P) and thrombin caused an increase in cell stiffness by up to 200 per cent, whereas in most cell strains, exposure to latrunculin A, isoproterenol, dibutryl cyclic-AMP or Y-27632 caused a decrease in cell stiffness by up to 80 per cent, highlighting that SC cells possess a remarkably wide contractile scope. Drug responses were variable across donors. S1P, for example, caused 200 per cent stiffening in one donor strain but only 20 per cent stiffening in another. Isoproterenol caused dose-dependent softening in three donor strains but little or no response in two others, a finding mirrored by changes in traction forces and consistent with the level of expression of β(2)-adrenergic receptors. Despite donor variability, those drugs that typically increase outflow resistance systematically caused cell stiffness to increase, while in most cases, those drugs that typically decrease outflow resistance caused cell stiffness to decrease. These findings establish the endothelial cell of SC as a reactive but variable mechanical component of the aqueous humour outflow pathway. Although the mechanism and locus of increased outflow resistance remain unclear, these data suggest the SC endothelial cell to be a modulator of outflow resistance.