Evaluating the evidence on genotoxicity and reproductive toxicity of carbon black: a critical review

The interactions of subcellular organelles in pulmonary fibrosis induced by carbon black nanoparticles: a comprehensive review

Owing to the widespread use and improper emissions of carbon black nanoparticles (CBNPs), the adverse effects of CBNPs on human health have attracted much attention. In toxicological research, carbon black is frequently utilized as a negative control because of its low toxicity and poor solubility. However, recent studies have indicated that inhalation exposure to CBNPs could be a risk factor for severe and prolonged pulmonary inflammation and fibrosis. At present, the pathogenesis of pulmonary fibrosis induced by CBNPs is still not fully elucidated, but it is known that with small particle size and large surface area, CBNPs are more easily ingested by cells, leading to organelle damage and abnormal interactions between organelles. Damaged organelle and abnormal organelles interactions lead to cell structure and function disorders, which is one of the important factors in the development and occurrence of various diseases, including pulmonary fibrosis. This review offers a comprehensive analysis of organelle structure, function, and interaction mechanisms, while also summarizing the research advancements in organelles and organelle interactions in CBNPs-induced pulmonary fibrosis.

Assessment of interactions between elemental carbon and metals in black carbon: Hydroxyl radical generation and glutathione depletion

Elemental carbon (EC) and metals are two important parts of atmospheric black carbon (BC). However, little information is available regarding the interaction between them and its impacts on the reactive oxygen species (ROS) formation and physiological antioxidants depletion. In this study, we chose six most frequently detected metals (Cu(Ⅱ), Fe(Ⅲ), Mn(Ⅱ), Cr(Ⅲ), Pb(Ⅱ) and Zn(Ⅱ)) in BC and examined their interactions with EC in the ROS generation and glutathione (GSH) oxidation. Results showed that only Cu(Ⅱ) and EC synergically promoted the GSH oxidation and hydroxyl radical (•OH) generation. Other five metals had negligible effects on the GSH oxidation regardless of the presence or absence of EC. The synergistic interaction between Cu(Ⅱ) and EC could be attributed to the superior electrical conductivity of EC. In the process, EC transferred electrons from the adjacent GSH to Cu(Ⅱ) through its graphitic carbon framework to yield Cu(Ⅰ) and GSH radical. Cu(Ⅰ) further reacted with dioxygen to generate •OH, which eventually led to the oxidation of GSH. Our results revealed a new driving force inducing the ROS formation and GSH depletion as well as provided novel insights into the risk assessment of BC.

Detection and characterisation of microplastics in tap water from Gauteng, South Africa

This study reports the presence, concentration, and characteristics of microplastics (MPs) in tap water in three suburbs in Gauteng Province in South Africa. Physical characterisation was conducted using stereomicroscopy and scanning electron microscopy following staining of MPs with the Rose Bengal dye. The concentrations of MPs in all samples ranged from 4.7 to 31 particles/L, with a mean of 14 ± 5.6 particles/L. Small-sized (<1 mm) and fibrous-shaped MPs were most abundant in all samples. Fibers accounted for 83.1% of MPs in samples from all the three areas, followed by fragments (12.4%), pellets/beads (3.1%), and films (1.5%), with a minor variation in the distribution of shapes and sizes in samples from each area. Raman microspectroscopy was used for chemical analysis, and five polymers were identified, namely: high-density polyethylene, polyurethane, polyethylene terephthalate, poly(hexamethylene terephtalamide), and poly(acrylamide-co-acrylic acid). C.I Pigment Red 1, C.I. Solvent Yellow 4, Potassium indigotetrasulphonate, and C.I Pigment Black 7 were the colourants detected. These colourants are carcinogenic and mutagenic and are potentially toxic to humans. The prevalence of MPs in tap water implies their inadequate removal during water treatment. For instance, the presence of poly(AM-co-AA) suggests that drinking water treatment plants may be a potential source of MPs in tap water. Other polymers, e.g., high-density polyethylene may be released from pipes during the transportation of drinking water. The estimated daily consumption of MPs from tap water was 1.2, 0.71, and 0.50 particles/kg.day for children, men, and women, respectively. The findings of this study provide evidence of the presence of MPs in drinking water in South Africa, thus giving some insights into the performance of treatment plants in removing these contaminants and a benchmark for the formulation of standard limits for the amount of MPs in drinking water.

An In Vitro Model to Assess Early Immune Markers Following Co-Exposure of Epithelial Cells to Carbon Black (Nano)Particles in the Presence of S. aureus: A Role for Stressed Cells in Toxicological Testing

The exposure of human lung and skin to carbon black (CB) is continuous due to its widespread applications. Current toxicological testing uses 'healthy' cellular systems; however, questions remain whether this mimics the everyday stresses that human cells are exposed to, including infection. Staphylococcus aureus lung and skin infections remain prevalent in society, and include pneumonia and atopic dermatitis, respectively, but current in vitro toxicological testing does not consider infection stress. Therefore, investigating the effects of CB co-exposure in 'stressed' infected epithelial cells in vitro may better approximate true toxicity. This work aims to study the impact of CB exposure during Staphylococcus aureus infection stress in A549 (lung) and HaCaT (skin) epithelial cells. Physicochemical characterisation of CB confirmed its dramatic polydispersity and potential to aggregate. CB significantly inhibited S. aureus growth in cell culture media. CB did not induce cytokines or antimicrobial peptides from lung and skin epithelial cells, when given alone, but did reduce HaCaT and A549 cell viability to 55% and 77%, respectively. In contrast, S. aureus induced a robust interleukin (IL)-8 response in both lung and skin epithelial cells. IL-6 and human beta defensin (hβD)-2 could only be detected when cells were stimulated with S. aureus with no decreases in cell viability. However, co-exposure to CB (100 µg/mL) and S. aureus resulted in significant inhibition of IL-8 (compared to S. aureus alone) without further reduction in cell viability. Furthermore, the same co-exposure induced significantly more hβD-2 (compared to S. aureus alone). This work confirms that toxicological testing in healthy versus stressed cells gives significantly different responses. This has significant implications for toxicological testing and suggests that cell stresses (including infection) should be included in current models to better represent the diversity of cell viabilities found in lung and skin within a general population. This model will have significant application when estimating CB exposure in at-risk groups, such as factory workers, the elderly, and the immunocompromised.

A review of carbon nanomaterials/bacterial cellulose composites for nanomedicine applications

Carbon nanomaterials (CNMs) mainly include fullerene, carbon nanotubes, graphene, carbon quantum dots, nanodiamonds, and their derivatives. As a new type of material in the field of nanomaterials, it has outstanding physical and chemical properties, such as minor size effects, substantial specific surface area, extremely high reaction activity, biocompatibility, and chemical stability, which have attracted widespread attention in the medical community in the past decade. However, the single use of carbon nanomaterials has problems such as self-aggregation and poor water solubility. Researchers have recently combined them with bacterial cellulose to form a new intelligent composite material to improve the defects of carbon nanomaterials. This composite material has been widely synthesized and used in targeted drug delivery, biosensors, antibacterial dressings, tissue engineering scaffolds, and other nanomedicine fields. This paper mainly reviews the research progress of carbon nanomaterials based on bacterial cellulose in nanomedicine. In addition, the potential cytotoxicity of these composite materials and their components in vitro and in vivo was discussed, as well as the challenges and gaps that need to be addressed in future clinical applications.

Isolation of Carbon Black from Soils by Dispersion for Analysis: Quantitation and Characterization by Field Flow Fractionation Techniques

In the present work, a procedure based on a dispersive medium for carbon black (CB) isolation from soil samples for analysis was proposed for the first time. Polymeric and biological dispersants and a sequential use of both dispersants were assayed. Asymmetrical flow field flow fractionation with dynamic light scattering detector (AF4-DLS) and sedimentation field flow fractionation with multi-angle light scattering detector (SdF3-MALS) were used for CB quantitation and characterization in the achieved dispersions. Soil samples contaminated with CB were processed, and CB isolation depended on the solid size distribution and composition and dispersant nature. More quantitative isolations were achieved for the four soils treated by the biological dispersant. As the organic matter percentage is higher in soil, the CB isolation was better, varying between 75 and 99% with standard deviation (s) ⩽ 2% for all soils. A soil contaminated with a CB-based pigment paste was analyzed, achieving (99 ± 2)% expressed as expanded uncertainty (K = 2) of dispersive isolation by the biological dispersant, and the sampling was scaled to 250 g of soil with positive results. The procedure was completed by CB recovery to obtain a solid residue able to be reused if necessary. For the filter-aided recovery step, different membranes (fiberglass, nylon, and Teflon) with a pore size between 0.1 and 5 μm were tested. The quantitation of the CB retained in the filter was measured by diffuse reflectance spectroscopy. Teflon (0.10 μm) provided better results for CB recovery, and its re-dispersion was also studied with suitable results. Determination of CB from the filters by diffuse reflectance spectrometry provided the same results than AF4 for CB dispersions.

Adverse Effects of Prenatal Exposure to Oxidized Black Carbon Particles on the Reproductive System of Male Mice

Ambient black carbon (BC), a main constituent of atmospheric particulate matter (PM), is a primary particle that is mainly generated by the incomplete combustion of fossil fuel and biomass burning. BC has been identified as a potential health risk via exposure. However, the adverse effects of exposure to BC on the male reproductive system remain unclear. In the present study, we explored the effects of maternal exposure to oxidized black carbon (OBC) during pregnancy on testicular development and steroid synthesis in male offspring. Pregnant mice were exposed to OBC (467 μg/kg BW) or nanopure water (as control) by intratracheal instillation from gestation day (GD) 4 to GD 16.5 (every other day). We examined the testicular histology, daily sperm production, serum testosterone, and mRNA expression of hormone synthesis process-related factors of male offspring at postnatal day (PND) 35 and PND 84. Histological examinations exhibited abnormal seminiferous tubules with degenerative changes and low cellular adhesion in testes of OBC-exposed mice at PND 35 and PND 84. Consistent with the decrease in daily sperm production, the serum testosterone level of male offspring of OBC-exposed mice also decreased significantly. Correspondingly, mRNA expression levels of hormone-synthesis-related genes (i.e., StAR, P450scc, P450c17, and 17β-HSD) were markedly down-regulated in male offspring of PND 35 and PND 84, respectively. In brief, these results suggest that prenatal exposure has detrimental effects on mouse spermatogenesis in adult offspring.

Overall distribution of tire-wear particles, nano‑carbon black, and heavy metals in size-fractionated road dust collected from steel industrial complexes

Tire-wear particles (TWP) from vehicles serves as a non-exhaust emission source. The mass content of metallic species in road dust may increase owing to the traffic of heavy vehicles and industrial activity; consequently, metallic particles are also present in road dust. Herein, road dust collected from steel industrial complexes with high traffic of high-weight vehicles and the composition distribution of five size-fractioned particle sizes were analyzed. Road dust samples were collected from three areas near steelmaking complexes. The mass distribution of TWP, carbon black (CB), bituminous coal, and heavy metals (Fe, Zn, Mn, Pb, Ni, As, Cu, Cd, and Hg) in different size fractions of road dust was quantified by combining four different analytical techniques. In the magnetic separation for <45 μm fraction, 34.4 wt% and 50.9 wt% was removed for steelmaking and steel-related industrial complexes, respectively. As the particle size decreased, the mass content of Fe, Mn, and TWP increased. The enrichment factors of Mn, Zn, and Ni were higher than two, indicating that they were related to industrial activities in steel complexes. The maximum concentrations of TWP and CB originating from the vehicle varied depending on the region and particle size range: TWP 2.066 wt% at 45-75 μm (industrial complex) and CB 5.559 wt% at 75-160 μm (steel complex). Coal was only found in the steel complex. Finally, to reduce the exposure of the finest particles to road dust, three methods were suggested. Magnetic fraction must be removed from road dust using magnetic separation; the fly dust of coal during transportation must be suppressed, and covers must be used in coal yards; the mass contents of TWP and CB in road dust should be removed by vacuum cleaning instead of water flushing.

Comparing the Toxicological Responses of Pulmonary Air-Liquid Interface Models upon Exposure to Differentially Treated Carbon Fibers

In recent years, the use of carbon fibers (CFs) in various sectors of industry has been increasing. Despite the similarity of CF degradation products to other toxicologically relevant materials such as asbestos fibers and carbon nanotubes, a detailed toxicological evaluation of this class of material has yet to be performed. In this work, we exposed advanced air-liquid interface cell culture models of the human lung to CF. To simulate different stresses applied to CF throughout their life cycle, they were either mechanically (mCF) or thermo-mechanically pre-treated (tmCF). Different aspects of inhalation toxicity as well as their possible time-dependency were monitored. mCFs were found to induce a moderate inflammatory response, whereas tmCF elicited stronger inflammatory as well as apoptotic effects. Furthermore, thermal treatment changed the surface properties of the CF resulting in a presumed adhesion of the cells to the fiber fragments and subsequent cell loss. Triple-cultures encompassing epithelial, macrophage, and fibroblast cells stood out with an exceptionally high inflammatory response. Only a weak genotoxic effect was detected in the form of DNA strand breaks in mono- and co-cultures, with triple-cultures presenting a possible secondary genotoxicity. This work establishes CF fragments as a potentially harmful material and emphasizes the necessity of further toxicological assessment of existing and upcoming advanced CF-containing materials.

Comparative Assessment of Microplastics in Surface Waters and Sediments of the Vaal River, South Africa: Abundance, Composition, and Sources

We extracted microplastics from surface water and sediment samples from the Vaal River in Johannesburg, South Africa. Average abundances of 0.61 ± 0.57 particles/ m 3 and 4.6 × 10²  ± 2.8 × 10²  particles/kg dry weight were recorded for water and sediment samples, respectively. In both sediment and water samples, more than 80% of microplastics were fragments and fibers of smaller than 2 mm. High-density polyethylene, low-density polyethylene, and polypropylene were the dominant polymers identified in both sample types. In addition, polyethylene co-vinyl acetate, polyester, polyurethane, and polyethylene/hexene-1-copolymer were also detected in sediment samples. Colored microplastics were the most commonly observed in both sample types; pigment yellow 83 was detected in surface water, and carbon black was detected in both sediment and water samples during Raman analysis. Taking into consideration the physical and chemical characteristics of the detected microplastics, their potential sources include inflow from tributaries, surface run-off from urban city centers, recreational activities, and wastewater effluent from industries and households. Environ Toxicol Chem 2022;41:3029-3040. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Estimation of the concentration of nano-carbon black in tire-wear particles using emission factors of PM10, PM2.5, and black carbon

Particulate matter (PM) from automobile exhaust has drastic effects on human health. The enforcement of environmental laws has controlled vehicle emissions and reduced the total PM. However, another significant source of PM is debris from tire wear, break wear, and road wear. In particular, tire-wear particles (TWPs) are further fragmented into nanoparticles, similar to the PM_x or black carbon (BC) sources. As approximately 30 wt% of carbon black (CB) is used as filler in tires, TWPs can fragment into free-bound nano-CB. This study evaluates the emission factors of BC from the ternary plots of PM_x and BC to estimate the concentration of nano-CB in TWPs. Based on the emission factors of BC for TWP, approximately 500 monitoring data points were acquired at four different sites. Semi-closed sites in a field measurement test have 2.9-4.0 times larger BC concentration than open sites. The mass concentration of nano-CB evaluated with the BC data and emission factors at the open sites is 22.47-23.96 ng/m³, whereas that at the semi-closed sites is 66.32-90.33 ng/m³. Transmission electron microscopy analysis with scanning mobility particle sizer and selected-area electron diffraction reveals grape-like aggregated nanoparticles, which is considered as CB. To compare the effect of the washing out of airborne particulates by rain, further analysis is conducted on the interior and exterior of the tunnel on a rainy day. While the concentration of PMs was effectively reduced by rainfall, the amount of BC and CB in the interior of a tunnel was not changed. Namely, even under rainfall, nano-CB still exists in the tunnels and thus free-bound CB and nanoparticles released from TWP will be effected on the human health.

Assessment of primary and inflammation-driven genotoxicity of carbon black nanoparticles in vitro and in vivo

Carbon black nanoparticles (CBNPs) have a large surface area/volume ratio and are known to generate oxidative stress and inflammation that may result in genotoxicity and cancer. Here, we evaluated the primary and inflammatory response-driven (i.e. secondary) genotoxicity of two CBNPs, Flammruss101 (FL101) and PrintexXE2B (XE2B) that differ in size and specific surface area (SSA), and cause different amounts of reactive oxygen species. Three doses (low, medium and high) of FL101 and XE2B were assessed in vitro in the lung epithelial (A549) and activated THP-1 (THP-1a) monocytic cells exposed in submerged conditions for 6 and 24 h, and in C57BL/6 mice at day 1, 28 and 90 following intratracheal instillation. In vitro, we assessed pro-inflammatory response as IL-8 and IL-1β gene expression, and in vivo, inflammation was determined as inflammatory cell infiltrates in bronchial lavage (BAL) fluid and as histological changes in lung tissue. DNA damage was quantified in vitro and in vivo as DNA strand breaks levels by the alkaline comet assay. Inflammatory responses in vitro and in vivo correlated with dosed CBNPs SSA. Both materials induced DNA damage in THP-1a (correlated with dosed mass), and only XE2B in A549 cells. Non-statistically significant increase in DNA damage in vivo was observed in BAL cells. In conclusion, this study shows dosed SSA predicted inflammation both in vivo and in vitro, whereas dosed mass predicted genotoxicity in vitro in THP-1a cells. The observed lack of correlation between CBNP surface area and genotoxicity provides little evidence of inflammation-driven genotoxicity in vivo and in vitro.

Chronic carbon black nanoparticles exposure increases lung cancer risk by affecting the cell cycle via circulatory inflammation

As a widely used pure elemental carbon in colloidal particles, carbon black was listed as a group 2B carcinogen by IARC in 2010. The most available mechanism information about carbon black and carcinogenesis are from in vivo or in vitro studies. However, few studies concerned the nanoparticle's real-ambient exposure causing systemic change and further affecting the target organ. Herein, we used an ex vivo biosensor assay to investigate the transcriptome change of primary bronchial epithelial cells after treatment with the plasma from workers with long-term occupational carbon black exposure history. Based on ex vivo biosensor assay and transcriptome sequencing, we found the effect of internal systemic environment on epithelial cells after carbon black exposure was an inflammatory response, which mainly activates cell cycle-related pathways. After exposure to carbon black, the internal systemic environment could activate cancer-related pathways like epithelial-mesenchymal transition, hypoxia, TNF-α signaling via NF-κB. The hub genes in the carbon black group (CDC20 and PLK1) and their correlation with the systemic environment were uncovered by constructing the protein-protein interaction network. Inflammatory cytokines, especially CRP, were strongly correlated with the expression of CDC20 and PLK1. Besides, we also find a strong correlation between CDC20 and cytokinesis-block micronucleus endpoints in peripheral blood (rho = 0.591, P < 0.001). Our results show that long-term carbon black exposure might activate cell cycle-related pathways through circulating inflammation and increase the risk of cancer, while the oxidative stress caused by diesel exhaust particles are mainly related to PAHs exposure. After exposure to carbon black, the systemic environment could activate cancer-related pathways like diesel exhaust particles, increasing the risk of lung cancer. These attempts might provide a further understanding of the indirect effect of chronic occupational inhaled carbon black exposure on pulmonary carcinogenesis.

Systematic review on primary and secondary genotoxicity of carbon black nanoparticles in mammalian cells and animals

Carbon black exposure causes oxidative stress, inflammation and genotoxicity. The objective of this systematic review was to assess the contributions of primary (i.e. direct formation of DNA damage) and secondary genotoxicity (i.e., DNA lesions produced indirectly by inflammation) to the overall level of DNA damage by carbon black. The database is dominated by studies that have measured DNA damage by the comet assay. Cell culture studies indicate a genotoxic action of carbon black, which might be mediated by oxidative stress. Many in vivo studies originate from one laboratory that has investigated the genotoxic effects of Printex 90 in mice by intra-tracheal instillation. Meta-analysis and pooled analysis of these results demonstrate that Printex 90 exposure is associated with a slightly increased level of DNA strand breaks in bronchoalveolar lavage cells and lung tissue. Other types of genotoxic damage have not been investigated as thoroughly as DNA strand breaks, although there is evidence to suggest that carbon black exposure might increase the mutation frequency and cytogenetic endpoints. Stratification of studies according to concurrent inflammation and DNA damage does not indicate that carbon black exposure gives rise to secondary genotoxicity. Even substantial pulmonary inflammation is at best only associated with a weak genotoxic response in lung tissue. In conclusion, the review indicates that nanosized carbon black is a weak genotoxic agent and this effect is more likely to originate from a primary genotoxic mechanism of action, mediated by e.g., oxidative stress, than inflammation-driven (secondary) genotoxicity.

Life-Related Hazards of Materials Applied to Mg–S Batteries

Nowadays, rechargeable batteries utilizing an S cathode together with an Mg anode are under substantial interest and development. The review is made from the point of view of materials engaged during the development of the Mg–S batteries, their sulfur cathodes, magnesium anodes, electrolyte systems, current collectors, and separators. Simultaneously, various hazards related to the use of such materials are discussed. It was found that the most numerous groups of hazards are posed by the material groups of cathodes and electrolytes. Such hazards vary widely in type and degree of danger and are related to human bodies, aquatic life, flammability of materials, or the release of flammable or toxic gases by the latter.

Exploring graphene-based materials' genotoxicity: inputs of a screening method

Graphene-based materials (GBMs) are promising nanomaterials, and several innovations depend on their use. However, the assessment of their potential hazard must be carefully explored before entering any market. GBMs are indeed well-known to induce various biological impacts, including oxidative stress, which can potentially lead to DNA damage. Genotoxicity is a major endpoint for hazard assessment and has been explored for GBMs, but the available literature shows conflicting results. In this study, we assessed the genotoxicity of 13 various GBMs, one carbon black and one amorphous silica through a DNA damage response assay (using a human respiratory cell model, BEAS-2B). Concurrently, oxidative stress was assessed through a ROS production quantification (DCFH-DA assay using a murine macrophage model, RAW 264.7). We also performed a full physicochemical characterization of our samples to explore potential structure-activity relationships involving genotoxicity. We observed that surface oxidation appears linked to genotoxicity response and were able to distinguish several groups within our studied GBMs showing different genotoxicity results. Our findings highlight the necessity to individually consider each nanoform of GBMs since the tested samples showed various results and modes of action. We propose this study as a genotoxicity assessment using a high-throughput screening method and suggest few hypotheses concerning the genotoxicity mode of action of GBMs.

Oxidized carbon black nanoparticles induce endothelial damage through C-X-C chemokine receptor 3-mediated pathway

Oxidation of engineered nanomaterials during application in various industrial sectors can alter their toxicity. Oxidized nanomaterials also have widespread industrial and biomedical applications. In this study, we evaluated the cardiopulmonary hazard posed by these nanomaterials using oxidized carbon black (CB) nanoparticles (CBox) as a model particle. Particle surface chemistry was characterized by X-ray photo electron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR). Colloidal characterization and in vitro dosimetry modeling (particle kinetics, fate and transport modeling) were performed. Lung inflammation was assessed following oropharyngeal aspiration of CB or oxidized CBox particles (20 μg per mouse) in C57BL/6J mice. Toxicity and functional assays were also performed on murine macrophage (RAW 264.7) and endothelial cell lines (C166) with and without pharmacological inhibitors. Oxidant generation was assessed by electron paramagnetic resonance spectroscopy (EPR) and via flow cytometry. Endothelial toxicity was evaluated by quantifying pro-inflammatory mRNA expression, monolayer permeability, and wound closure. XPS and FTIR spectra indicated surface modifications, the appearance of new functionalities, and greater oxidative potential (both acellular and in vitro) of CBox particles. Treatment with CBox demonstrated greater in vivo inflammatory potentials (lavage neutrophil counts, secreted cytokine, and lung tissue mRNA expression) and air-blood barrier disruption (lavage proteins). Oxidant-dependent pro-inflammatory signaling in macrophages led to the production of CXCR3 ligands (CXCL9,10,11). Conditioned medium from CBox-treated macrophages induced significant elevation in endothelial cell pro-inflammatory mRNA expression, enhanced monolayer permeability and impairment of scratch healing in CXCR3 dependent manner. In summary, this study mechanistically demonstrated an increased biological potency of CBox particles and established the role of macrophage-released chemical mediators in endothelial damage.

Exposure to ambient particulate matter and biomass burning during pregnancy: associations with birth weight in Thailand

BACKGROUND

There is a growing evidence that exposure to ambient particulate air pollution during pregnancy is associated with adverse birth outcomes, including reduced birth weight (BW). The objective of this study was to quantify associations between BW and exposure to particulate matter (PM) and biomass burning during pregnancy in Thailand.

METHODS

We collected hourly ambient air pollutant data from ground-based monitors (PM with diameter of <10 µm [PM₁₀], Ozone [O₃], and nitrogen dioxide [NO₂]), biomass burning from satellite remote sensing data, and individual birth weight data during 2015-2018. We performed a semi-ecological analysis to evaluate the association between mean trimester exposure to air pollutants and biomass burning with BW and low-birth weight (LBW) (<2500 g), adjusting for gestation age, sex, previous pregnancies, mother's age, heat index, season, year, gaseous pollutant concentrations, and province. We examined potential effect modification of PM₁₀ and biomass burning exposures by sex.

RESULTS

There were 83,931 eligible births with a mean pregnancy PM₁₀ exposure of 39.7 µg/m³ (standard deviation [SD] = 7.7). The entire pregnancy exposure was associated with reduced BW both for PM₁₀ (-6.81 g per 10 µg/m³ increase in PM₁₀ [95% CI = -12.52 to -1.10]) and biomass burning (-6.34 g per 1 SD increase in fires/km² [95% CI = -11.35 to -1.34]) only after adjustment for NO₂. In contrast with these findings, a reduced odds ratio (OR) of LBW was associated with PM₁₀ exposure only in trimesters one and two, with no relationship across the entire pregnancy period. Associations with biomass burning were limited to increased ORs of LBW with exposure in trimester three, but only for male births.

CONCLUSION

Based on our results, we encourage further investigation of air pollution, biomass burning and BW in Thailand and other low-income and middle-income countries.

Current opinion on risk assessment of cosmetics

Risk assessment of cosmetic ingredients is a useful scientific method to characterize potential adverse effects resulting from using cosmetics. The process of risk assessment consists of four steps: hazard identification, dose-response assessment, exposure assessment, and risk characterization. Hazard identification of chemicals refers to the initial stage of risk assessment and generally utilizes animal studies to evaluate toxicity. Since 2013, however, toxicity studies of cosmetic ingredients using animals have not been permitted in the EU and alternative toxicity test methods for animal studies have momentum to be developed for cosmetic ingredients. In this paper, we briefly review the alternative test methods that are available for cosmetic ingredients including read-across, in silico, in chemico, and invitro methods. In addition, new technologies such as omics and artificial intelligence (AI) have been discussed to expand or improve the knowledge and hazard identification of cosmetic ingredients. Aggregate exposure of cosmetic ingredients is another safety issue and methods for its improvement were reviewed. There have been concerns over the safety of nano-cosmetics for a long time, but the risk of nano-cosmetics remains unclear. Therefore, current issues of cosmetic risk assessment are discussed and expert opinion will be provided for the safety of cosmetics.

Suitability of Nanoparticles to Face Benzo(a)pyrene-Induced Genetic and Chromosomal Damage in M. galloprovincialis. An In Vitro Approach

Benzo(a)pyrene (B(a)P) is a well-known genotoxic agent, the removal of which from environmental matrices is mandatory, necessitating the application of cleaning strategies that are harmless to human and environmental health. The potential application of nanoparticles (NPs) in the remediation of polluted environments is of increasing interest. Here, specifically designed NPs were selected as being non-genotoxic and able to interact with B(a)P, in order to address the genetic and chromosomal damage it produces. A newly formulated pure anatase nano-titanium (nano-TiO2), a commercial mixture of rutile and anatase, and carbon black-derived hydrophilic NPs (HNP) were applied. Once it had been ascertained that the NPs selected for the work did not induce genotoxicity, marine mussel gill biopsies were exposed in vitro to B(a)P (2 μg/mL), alone and in combination with the selected NPs (50 µg/mL nano-TiO2, 10 µg/mL HNP). DNA primary reversible damage was evaluated by means of the Comet assay. Chromosomal persistent damage was assessed on the basis of micronuclei frequency and nuclear abnormalities by means of the Micronucleus-Cytome assay. Transmission Electron Microscopy (TEM) was performed to investigate the mechanism of action exerted by NPs. Pure Anatase n-TiO2 was found to be the most suitable for our purpose, as it is cyto- and genotoxicity free and able to reduce the genetic and chromosomal damage associated with exposure to B(a)P.

Differentiation of carbon black from black carbon using a ternary plot based on elemental analysis

Carbon black (CB) is composed of engineered nanoparticles that are commercially produced by partial combustion of hydrocarbons. It is mainly used as a reinforcing agent in vehicle tires. Although the potential health effects of CB have been investigated extensively, some toxicological reports interchange CB with black carbon (BC), which has similar features, thereby misusing the term. BC is an undesirable byproduct of the incomplete combustion of fuels. Therefore, there is a need to differentiate CB from the unintentionally produced nanomaterials (BC) in nano-toxicity, environmental, and human health studies. To distinguish clearly CB from BC, it is important to find the key parameters from several characteristics of two substances. The fundamental physicochemical properties of commercial CB and naturally formed BC were conducted. Based on the elemental analysis, we found three key factors, which could be used to differentiate the CB from BC. And thus, herein, we propose a ternary plot of the aH/C-log(C/b)-1/H combination for use in differentiating CB from BC. The plot of the 100H/C-log(C/10)-1/H combination of elemental ratios separated the CB domain from the BC domain symmetrically. The effectiveness of the ternary chart was validated using 37 samples (nine samples in this work, 25 sample results taken from references studies, and three samples from the field). Therefore, the ternary plot could be used as a prescreening tool for distinguishing CB from BC.

Continuous Exposure to Low Doses of Ultrafine Black Carbon Reduces the Vitality of Immortalized Lung-Derived Cells and Activates Senescence

Combustion-derived nanomaterials are noxious ultrafine (<100 nm) aerosol by-products of human activity. They pose threats to pulmonary health due to their small size, allowing them to penetrate alveoli causing detrimental responses downstream. Information regarding the cellular activity that connects nanocarbon particle exposure to poor pulmonary health remains lacking. We hypothesized that low-dose and long-term administrations of carbonaceous nanoparticles contribute to lung irritation by adversely affecting respiratory cells that function as the first line of defense. Responses to ultrafine black carbon (UBC), a key component of airborne pollutants, by human lung A549, murine lung LA4 epithelial cells, human peripheral-blood monocytes THP1, and murine macrophages RAW264.7 were investigated. The cells were first plated on day zero and were fed fresh UBC suspended in culture media on days one, four, and seven. The exposure regimen included three different concentrations of UBC. On day ten, all cells were harvested, washed, and assayed. The impact on cellular viability revealed that UBC was only moderately cytotoxic, while metabolic activity was significantly diminished in a dose-dependent manner. Additionally, beta-galactosidase proportionally increased with UBC concentration compared to untreated cells, indicating that cellular senescence was promoted across all cell types. The implemented regimen caused minimal toxicity yet demonstrated different cellular modifications across the cell lines of both species, inducing changes to enzyme vitality and cellular fitness. The data suggested that compounding nanosized black carbon exposure could negatively impair overall pulmonary health by distinctively modifying intracellular behavior.

A Review on Graphene’s Light Stabilizing Effects for Reduced Photodegradation of Polymers

Graphene, the newest member of the carbon’s family, has proven its efficiency in improving polymers’ resistance against photodegradation, even at low loadings equal to 1 wt% or lower. This protective role involves a multitude of complementary mechanisms associated with graphene’s unique geometry and chemistry. In this review, these mechanisms, taking place during both the initiation and propagation steps of photodegradation, are discussed concerning graphene and graphene derivatives, i.e., graphene oxide (GO) and reduced graphene oxide (rGO). In particular, graphene displays important UV absorption, free radical scavenging, and quenching capabilities thanks to the abundant π-bonds and sp2 carbon sites in its hexagonal lattice structure. The free radical scavenging effect is also partially linked with functional hydroxyl groups on the surface. However, the sp2 sites remain the predominant player, which makes graphene’s antioxidant effect potentially stronger than rGO and GO. Besides, UV screening and oxygen barriers are active protective mechanisms attributed to graphene’s high surface area and 2D geometry. Moreover, the way that graphene, as a nucleating agent, can improve the photostability of polymers, have been explored as well. These include the potential effect of graphene on increasing polymer’s glass transition temperature and crystallinity.

Identification of Plant Soot as Novel Safe Feed Additive: Evaluation of 90-Day Oral Toxicity and Prenatal Developmental Toxicity in Rats

Plant soot, as a novel feed additive, could not only improve digestive function but also adsorb mycotoxins and inhibit bacterial infections. The subchronic toxicity and prenatal developmental effects of plant soot were studied for the first time. Our results indicated that there was no subchronic toxicity in the range of 2,000–50,000 mg/kg plant soot added in the feed, and there was no significant difference in reproductive function, embryo development, and teratogenicity between the pregnant rats exposed to 312.5, 1,250, and 5,000 mg/kg plant soot and the control group. The maximum no-observed effect level (NOEL) of supplemental dosage in feed could be set to 50,000 mg/kg, and the maximum intragastric NOEL could be set to 5,000 mg/kg, which preliminarily provided guidance on daily additive amount or clinical protocols for plant soot, as well as promoting the development and application of this harmless antibiotic substitutes.

In Utero Exposure to Particulate Air Pollution during Pregnancy: Impact on Birth Weight and Health through the Life Course

In high-income countries, and increasingly in lower- and middle-income countries, chronic non-communicable diseases (NCDs) have become the primary health burden. It is possible that in utero exposure to environmental pollutants such as particulate matter (PM) may have an impact on health later in life, including the development of NCDs. Due to a lack of data on foetal growth, birth weight is often used in epidemiologic studies as a proxy to assess impacts on foetal development and adverse birth outcomes since it is commonly recorded at birth. There are no research studies with humans that directly link PM exposure in utero to birth weight (BW) and subsequently, the effects of lower BW on health outcomes in old age. It is, however, plausible that such associations exist, and it is thus important to assess the potential public health impacts of PM across the life course, and it is plausible to use birth weight as an indicator of risk. We therefore split this narrative review into two parts. In the first part, we evaluated the strength of the evidence on the impact of PM exposure during the entire pregnancy on birth weight outcomes in ten meta-analyses. In the second part, we reviewed the literature linking lower birth weight to childhood and adult chronic cardiovascular disease to explore the potential implications of PM exposure in utero on health later in life. Within the reviewed meta-studies on birth weight, there is sufficient evidence that PM pollution is associated with lower birth weight, i.e., the majority of meta-studies found statistically significant reductions in birth weight. From the second part of the review, it is evident that there is good evidence of associations between lower birth weight and subsequent cardiovascular disease risk. It is thus plausible that in utero exposure to PM is associated with lower birth weight and persisting biological changes that could be associated with adverse health effects in adulthood. Based on the reviewed evidence, however, the magnitude of later life cardiovascular health impacts from in utero exposure and its impact on BW are likely to be small compared to health effects from exposure to particulate air pollution over a whole lifetime.

The Toxicity of Secondary Lithium-Sulfur Batteries Components

Currently, apart from the widely known lithium-ion batteries, there are competitive solutions in the form of, for example, Li-S batteries. While the results of studies on the toxicity of Li-ion battery components are published, such studies on the components of Li-S cells are just beginning. The purpose of the current review was to identify materials used in the production of Li-S batteries and their toxicity, especially for humans. The review showed many kinds of materials with different levels of toxicity utilized for manufacturing of these cells. Some materials are of low toxicity, while some others are of the high one. A lot of materials have assigned different hazard statements. For some of the materials, no hazard statements were assigned, although such materials are toxic. No data related to the toxicity of some materials were found in the literature. This points out the need to further studies on their toxicity and legal actions to assign appropriate hazard statements.

Nanotoxicology: The Need for a Human Touch?

With the ever-expanding number of manufactured nanomaterials (MNMs) under development there is a vital need for nanotoxicology studies that test the potential for MNMs to cause harm to health. An extensive body of work in cell cultures and animal models is vital to understanding the physicochemical characteristics of MNMs and the biological mechanisms that underlie any detrimental actions to cells and organs. In human subjects, exposure monitoring is combined with measurement of selected health parameters in small panel studies, especially in occupational settings. However, the availability of further in vivo human data would greatly assist the risk assessment of MNMs. Here, the potential for controlled inhalation exposures of MNMs in human subjects is discussed. Controlled exposures to carbon, gold, aluminum, and zinc nanoparticles in humans have already set a precedence to demonstrate the feasibility of this approach. These studies have provided considerable insight into the potential (or not) of nanoparticles to induce inflammation, alter lung function, affect the vasculature, reach the systemic circulation, and accumulate in other organs. The need for further controlled exposures of MNMs in human volunteers - to establish no-effect limits, biological mechanisms, and provide vital data for the risk assessment of MNMs - is advocated.

Telomere length and genotoxicity in the lung of rats following intragastric exposure to food-grade titanium dioxide and vegetable carbon particles

Vegetable carbon (E153) and titanium dioxide (E171) are widely used as black and white food colour additives. The aim of this study was to assess gastrointestinal tight junction and systemic genotoxic effects in rats following exposure to E153 and E171 for 10 weeks by oral gavage once a week. The expression of tight junction proteins was assessed in intestinal tissues. Levels of DNA strand breaks, oxidatively damaged DNA and telomere length were assessed in secondary organs. Hydrodynamic suspensions of E153 and E173 indicated mean particles sizes of 230 and 270 nm, respectively, and only E153 gave rise to intracellular production of reactive oxygen species in colon epithelial (Caco-2) cells. Rats exposed to E153 (6.4 mg/kg/week) or E171 (500 mg/kg/week) had decreased gene expression of the tight junction protein TJP1 (P < 0.05). E153 (6.4 mg/kg/week) also decreased OCLN (P < 0.05) in the colon and occludin protein expression in the small intestine (P < 0.05). Furthermore, E153 or E171 exposed rats had shorter telomeres in the lung (P < 0.05). Plasma from particle-exposed rats also produced telomere shortening in cultured lung epithelial cells. There were unaltered levels of oxidatively damaged DNA in the liver and lung and no changes in the DNA repair activity of oxidatively damaged DNA in the lung. Altogether, these results indicate that intragastric exposure to E153 and E171 is associated with reduced tight junction protein expression in the intestinal barrier and telomere length shortening in the lung in rats.

Carbon content in airway macrophages and genomic instability in Chinese carbon black packers

Carbon black (CB) particulates as virtually pure elemental carbon can deposit deep in the lungs of humans. International Agency for Research on Cancer classified CB as a Group 2B carcinogen due to inconclusive human evidence. A molecular epidemiological study was conducted in an established cohort of CB packers (CBP) to assess associations between CB exposure and genomic instability in peripheral lymphocytes using cytokinesis-block micronucleus assay (CBMN). Carbon content in airway macrophages (CCAM) was quantified as a bio-effective dosimeter for chronic CB exposure. Dose-response observed in CBPs was compared to that seen in workers exposed to diesel exhaust. The association between CB exposure status and CBMN endpoints was identified in 85 CBPs and 106 non-CBPs from a 2012 visit and replicated in 127 CBPs and 105 non-CBPs from a 2018 visit. The proportion of cytoplasm area occupied by carbon particles in airway macrophages was over fivefold higher in current CBPs compared to non-CBPs and was associated with CBMN endpoints in a dose-dependent manner. CB aerosol and diesel exhaust shared the same potency of inducing genomic instability in workers. Circulatory pro-inflammatory factors especially TNF-α was found to mediate associations between CB exposure and CBMN endpoints. In vitro functional validation supported the role of TNF-α in inducing genomic instability. An estimated range of lower limits of benchmark dose of 4.19-7.28% of CCAM was recommended for risk assessment. Chronic CB exposure increased genomic instability in human circulation and this provided novel evidence supporting its reclassification as a human carcinogen.

Applications of Nanocellulose/Nanocarbon Composites: Focus on Biotechnology and Medicine

Nanocellulose/nanocarbon composites are newly emerging smart hybrid materials containing cellulose nanoparticles, such as nanofibrils and nanocrystals, and carbon nanoparticles, such as "classical" carbon allotropes (fullerenes, graphene, nanotubes and nanodiamonds), or other carbon nanostructures (carbon nanofibers, carbon quantum dots, activated carbon and carbon black). The nanocellulose component acts as a dispersing agent and homogeneously distributes the carbon nanoparticles in an aqueous environment. Nanocellulose/nanocarbon composites can be prepared with many advantageous properties, such as high mechanical strength, flexibility, stretchability, tunable thermal and electrical conductivity, tunable optical transparency, photodynamic and photothermal activity, nanoporous character and high adsorption capacity. They are therefore promising for a wide range of industrial applications, such as energy generation, storage and conversion, water purification, food packaging, construction of fire retardants and shape memory devices. They also hold great promise for biomedical applications, such as radical scavenging, photodynamic and photothermal therapy of tumors and microbial infections, drug delivery, biosensorics, isolation of various biomolecules, electrical stimulation of damaged tissues (e.g., cardiac, neural), neural and bone tissue engineering, engineering of blood vessels and advanced wound dressing, e.g., with antimicrobial and antitumor activity. However, the potential cytotoxicity and immunogenicity of the composites and their components must also be taken into account.

Toxicity of Zero- and One-Dimensional Carbon Nanomaterials

The zero (0-D) and one-dimensional (1-D) carbon nanomaterials have gained attention among researchers because they exhibit a larger surface area to volume ratio, and a smaller size. Furthermore, carbon is ubiquitously present in all living organisms. However, toxicity is a major concern while utilizing carbon nanomaterials for biomedical applications such as drug delivery, biosensing, and tissue regeneration. In the present review, we have summarized some of the recent findings of cellular and animal level toxicity studies of 0-D (carbon quantum dot, graphene quantum dot, nanodiamond, and carbon black) and 1-D (single-walled and multi-walled carbon nanotubes) carbon nanomaterials. The in vitro toxicity of carbon nanomaterials was exemplified in normal and cancer cell lines including fibroblasts, osteoblasts, macrophages, epithelial and endothelial cells of different sources. Similarly, the in vivo studies were illustrated in several animal species such as rats, mice, zebrafish, planktons and, guinea pigs, at various concentrations, route of administrations and exposure of nanoparticles. In addition, we have described the unique properties and commercial usage, as well as the similarities and differences among the nanoparticles. The aim of the current review is not only to signify the importance of studying the toxicity of 0-D and 1-D carbon nanomaterials, but also to emphasize the perspectives, future challenges and possible directions in the field.

Lysosomal dysfunction is associated with persistent lung injury in dams caused by pregnancy exposure to carbon black nanoparticles

AIMS

Carbon black nanoparticles (CBNPs) are widely used in industrial field. Sensitive stages such as pregnancy are assumed to be more susceptible to stimulus, however whether pregnancy exposure to CBNPs (PrE-to-CBNPs) would cause long-term toxic effects in dams and the underlying mechanisms remain poorly addressed. The present study is aimed to determine the long-term toxic effects of PrE-to-CBNPs in dams.

MATERIALS AND METHODS

The pregnant mice were randomly divided into control group, low (21 μg/animal), medium (103 μg/animal) and high (515 μg/animal) CBNPs-treated groups. From gestational day (GD) 9 to GD18, the pregnant mice were intranasal exposed. At 49 days after parturition, lung tissues and bronchoalveolar lavage fluid (BALF) were obtained. Weight change, lung histopathology, lung ultrastructural pathology, cell count in BALF, oxidative stress/inflammatory maker and autophagy/lysosome-related protein expression were determined.

KEY FINDINGS

PrE-to-CBNPs caused a dose-dependent persistent lung injury in mice even 49 days after parturition, including the deteriorative lung histopathological changes, elevation of oxidative stress marker Nrf-2, HO-1 and CHOP, infiltration of macrophage and increased mRNA expression of inflammatory cytokines in the lung tissues and elevation of cells in BALF. However, PrE-to-CBNPs did not induce significant neutrophil infiltration and fibrosis. Moreover, we found that CBNPs could deposit in the lysosomes and decrease cathepsin D (an important hydrolase in lysosome), which might be associated with the dysfunction of lysosome and autophagy.

SIGNIFICANCE

Our study demonstrated that PrE-to-CBNPs could result in long-term lung injury in dams, and lysosomal dysfunction was probably linked to this process.

Pregnancy exposure to carbon black nanoparticles exacerbates bleomycin-induced lung fibrosis in offspring via disrupting LKB1-AMPK-ULK1 axis-mediated autophagy

Accumulating evidence shows that carbon black nanoparticles (CBNPs) (one of the most used nanoparticles) can induce toxicity via induction of inflammation, oxidative stress and genotoxicity in vitro and in vivo, and epidemiological studies have indicated that the possible correlation between maternal immune activation and risk of developing neuropsychiatric disorder in the offspring. However, whether pregnancy exposure of CBNPs (Pr-CBNPs) enhances the susceptibility to bleomycin (BLM)-induced lung fibrosis in offspring is unknown. Herein, we demonstrated that Pr-CBNPs during gestational day 9-18 via intranasal administration could confer enhanced susceptibility to BLM-induced fibrotic response in offspring, including deteriorative lung pathologic changes and more collagen deposition. Intriguingly, we found that Pr-CBNPs repressed the activation of autophagy (an anti-fibrotic mechanism), which was moderately activated in offspring from mock group. Moreover, Pr-CBNPs was likely to disrupt the LKB1-AMPK-ULK1 axis (a key regulatory pathway for autophagy induction). In summary, this study provides the first evidence that pregnancy exposure to CBNPs can exacerbate BLM-induced lung fibrotic response in offspring probably through disruption of LKB1-AMPK-ULK1 axis-mediated autophagy.

Toxicity of carbon-based nanomaterials: Reviewing recent reports in medical and biological systems

Application of nanomaterials in our daily life is increasing, day in day out and concerns have raised about their toxicity for human and other organisms. In this manner, carbon-based nanomaterials have been applied to different products due to their unique physicochemical, electrical, mechanical properties, and biological compatibility. But, there are several reports about the negative effects of these materials on biological systems and cellular compartments. This review article describes the various types of carbon-based nanomaterials and methods that use for determining these toxic effects that are reported recently in the papers. Then, extensively discussed the toxic effects of these materials on the human and other living organisms and also their toxicity routs including Neurotoxicity, Hepatotoxicity, Nephrotoxicity, Immunotoxicity, Cardiotoxicity, Genotoxicity and epigenetic toxicity, Dermatotoxicity, and Carcinogenicity.

In vitro and in vivo toxic effects and inflammatory responses induced by carboxylated black carbon-lead complex exposure

Black carbon (BC) is a key component of atmospheric fine particulate matter (PM_2.5) and it tends to adsorb various pollutants (e.g., heavy metals and organics) during atmospheric transport. This adsorption leads to the complexity and uncertainty of the source and chemical composition of PM_2.5, making the toxicologic effects and health risks induced by PM2.5 difficult to determine. Here, we used carboxylated black carbon (c-BC) and c-BC-lead complexes (c-BC-Pb) to investigate the in vitro and in vivo toxic effects and inflammatory responses. The physicochemical properties of c-BC and c-BC-Pb complexes were characterized by the transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), and in ductively coupled plasma-atomic emission spectra (ICP-AES). Cytotoxicity in vitro showed that the exposure of human bronchial epithelial cells (BEAS-2B) to low-dose c-BC-Pb particles significantly induced greater toxicity than that of c-BC, suggesting that lead (Pb) might play an important role in induced cytotoxicity after combined exposure to c-BC-Pb particles. The findings were further confirmed by the results in vivo, which indicated that c-BC-Pb particles significantly induced inflammation and lung injury. Based on the results of this experiment, the differences in toxicity can be attributed to the synergistic effect of Pb on the BC particles, which play a synergistic role in vitro and in vivo in the development of toxicity. The c-BC-Pb particles model used in this study may be helpful for the evaluation of cytotoxicity induced by different sources of BC particles or BC-heavy metal complexes and provide a new approach for understanding PM_2.5-induced toxicity and health risks.

Carbon black suppresses the osteogenesis of mesenchymal stem cells: the role of mitochondria

BACKGROUND

The rapid increase in carbon black poses threats to human health. We evaluated the effect of CB (Printex 90) on the osteogenesis of bone-marrow-derived mesenchymal stem cells (MSCs). Mitochondria play an important role in the osteogenesis of MSCs and are potential targets of nanomaterials, so we studied the role of mitochondria in the CB Printex 90-induced effects on osteogenesis.

RESULTS

Low doses of Printex 90 (3 ng/mL and 30 ng/mL) that did not cause deleterious effects on MSCs' viability significantly inhibited osteogenesis of MSCs. Printex 90 caused down-regulation of osteoblastic markers, reduced activity of alkaline phosphatase (ALP), and poor mineralization of osteogenically induced MSCs. Cellular ATP production was decreased, mitochondrial respiration was impaired with reduced expression of ATPase, and the mitochondrial membrane was depolarized. The quantity and quality of mitochondria are tightly controlled by mitochondrial biogenesis, mitochondrial dynamics and mitophagy. The transcriptional co-activator and transcription factors for mitochondrial biogenesis, PGC-1α, Nrf1 and TFAM, were suppressed by Printex 90 treatment, suggesting that decreased biogenesis was caused by Printex 90 treatment during osteogenesis. Mitochondrial fusion and fission were significantly inhibited by Printex 90 treatment. PINK1 accumulated in Printex 90-treated cells, and more Parkin was recruited to mitochondria, indicating that mitophagy increased to remove the damaged mitochondria.

CONCLUSIONS

This is the first report of the inhibitory effects of CB on the osteogenesis of MSCs and the involvement of mitochondria in CB Printex 90-induced suppression of MSC osteogenesis.