The effects of nanomaterials as endocrine disruptors

Sub-chronic palladium nanoparticle effects on the endocrine reproductive system of female Wistar rats: Preliminary data

The technologically interesting properties of palladium nanoparticles (Pd-NPs) allowed their widespread industrial application, although concerns emerged on increasing general and occupational levels of exposure. In this context, to assess the toxicological behavior of Pd-NPs, and particularly their endocrine disruptive potential, has become a public health priority. Therefore, we evaluated Pd-NP impact on the female endocrine reproductive system of Wistar rats sub-chronically treated for 90 days with increasing doses of this xenobiotic (0.12, 1.2, and 12 µg/kg, administered at days 1, 30, and 60 for cumulative doses of 0.36, 3.6, and 36 µg/kg) via the intravenous route. In this regard, we investigated potential alterations in different sex hormone, for example, estradiol, follicle-stimulating hormone (FSH), luteinizing hormone, progesterone, and testosterone, serum concentrations. All treated groups showed significantly greater levels of FSH compared to controls, suggesting a possible impact of Pd-NPs on the regulatory system that controls the normal physiology of female reproductive function. Although relevant, since obtained under sub-chronic, low-dose conditions of exposure resembling those encountered in real-world scenarios, the present results are preliminary and require confirmation as well as identification of the possible underlining molecular mechanisms. From a public and occupational health perspective, implications for the reproductive health of exposed subjects and the next generations of women exposed during their childbearing age or pregnancy should be elucidated. This information is essential to elaborate adequate preventive strategies for assessing and controlling possible Pd-NPs adverse effects on the endocrine system.

Contaminant and Environmental Influences on Thyroid Hormone Action in Amphibian Metamorphosis

Aquatic and terrestrial environments are increasingly contaminated by anthropogenic sources that include pharmaceuticals, personal care products, and industrial and agricultural chemicals (i. e., pesticides). Many of these substances have the potential to disrupt endocrine function, yet their effect on thyroid hormone (TH) action has garnered relatively little attention. Anuran postembryonic metamorphosis is strictly dependent on TH and perturbation of this process can serve as a sensitive barometer for the detection and mechanistic elucidation of TH disrupting activities of chemical contaminants and their complex mixtures. The ecological threats posed by these contaminants are further exacerbated by changing environmental conditions such as temperature, photoperiod, pond drying, food restriction, and ultraviolet radiation. We review the current knowledge of several chemical and environmental factors that disrupt TH-dependent metamorphosis in amphibian tadpoles as assessed by morphological, thyroid histology, behavioral, and molecular endpoints. Although the molecular mechanisms for TH disruption have yet to be determined for many chemical and environmental factors, several affect TH synthesis, transport or metabolism with subsequent downstream effects. As molecular dysfunction typically precedes phenotypic or histological pathologies, sensitive assays that detect changes in transcript, protein, or metabolite abundance are indispensable for the timely detection of TH disruption. The emergence and application of 'omics techniques-genomics, transcriptomics, proteomics, metabolomics, and epigenomics-on metamorphosing tadpoles are powerful emerging assets for the rapid, proxy assessment of toxicant or environmental damage for all vertebrates including humans. Moreover, these highly informative 'omics techniques will complement morphological, behavioral, and histological assessments, thereby providing a comprehensive understanding of how TH-dependent signal disruption is propagated by environmental contaminants and factors.

Multi-walled carbon nanotubes inhibit estrogen receptor expression in vivo and in vitro through transforming growth factor beta1

Exposure to multi-walled carbon nanotubes (MWCNTs) is suspected to contribute to pulmonary fibrosis through modulation of transforming growth factor beta1 (TGF-β1). There is growing evidence that estrogen signaling is important in pulmonary function and modulates pro-fibrogenic signaling in multiple models of pulmonary fibrosis, however an interaction between MWCNT exposure and estrogen signaling in the lung is not known. The purpose of this work was to determine whether estrogen signaling in the lung is a target for MWCNTs and to identify potential signaling mechanisms mediating MWCNT-induced responses using a whole-body inhalation mouse model and an in vitro human lung cell model. Mice exposed to MWCNTs had reduced mRNA expression of estrogen receptor alpha and beta (Esr1 and Esr2, respectively) in lung tissue at multiple time-points post-exposure, whereas expression of g-protein coupled estrogen receptor1 (Gper1) was more variable. We localized ESR1 protein expression as primarily associated with bronchioles and within inflammatory macrophages. The reduction in estrogen receptor expression was concomitant to an increase in TGF-β1 levels in the bronchoalveolar lavage fluid (BALF) of MWCNT-exposed animals. We confirmed a role for TGF-β1 in mediating MWCNT-induced repression of ESR1 mRNA expression using a TGF-β type-I receptor inhibitor in bronchial epithelial cells in vitro. Overall these results highlight a novel mechanism of MWCNT-induced signaling where MWCNT-induced regulation of TGF-β1 represses estrogen receptor expression. Dysregulated estrogen signaling through altered receptor expression may have potential consequences on lung function.

New approaches to cope with possible harms of low-dose environmental chemicals

Low-dose environmental chemicals including endocrine-disrupting chemicals can disturb endocrine, nervous and immune systems. Traditional chemical-focused approaches, strict regulation and avoidance of exposure sources, can help protect humans from individual or several chemicals in the high-dose range, but their value in the low-dose range is questionable. First, exposure sources to problematic environmental chemicals are omnipresent, and many common pollutants present no safe level. In this situation, the value of any effort focusing on individual chemicals is very limited. Second, critical methodological issues, including the huge number of environmental chemicals, biological complexity of mixtures and non-linearity, make it difficult for risk assessment-based regulation to provide reliable permissible levels of individual chemicals. Third, the largest exposure source is already internal; human adipose tissue contains the most complex chemical mixtures. Thus, in the low-dose range, a paradigm shift is required from a chemical-focused to a human-focused approach for health protection. Two key questions are (1) how to control toxicokinetics of chemical mixtures to decrease their burden in critical organs and (2) how to mitigate early harmful effects of chemical mixtures at cellular levels. Many lifestyles can be evaluated for these purposes. Although both the chemical-focused and human-focused approaches are needed to protect humans, the human-focused holistic approach must be the primary measure in the low-dose range of environmental chemicals.

Role of Endocrine-Disrupting Engineered Nanomaterials in the Pathogenesis of Type 2 Diabetes Mellitus

Nanotechnology has enabled the development of innovative technologies and products for several industrial sectors. Their unique physicochemical and size-dependent properties make the engineered nanomaterials (ENMs) superior for devising solutions for various research and development sectors, which are otherwise unachievable by their bulk forms. However, the remarkable advantages mediated by ENMs and their applications have also raised concerns regarding their possible toxicological impacts on human health. The actual issue stems from the absence of systematic data on ENM exposure-mediated health hazards. In this direction, a comprehensive exploration on the health-related consequences, especially with respect to endocrine disruption-related metabolic disorders, is largely lacking. The reasons for the rapid increase in diabetes and obesity in the modern world remain largely unclear, and epidemiological studies indicate that the increased presence of endocrine disrupting chemicals (EDCs) in the environment may influence the incidence of metabolic diseases. Functional similarities, such as mimicking natural hormonal actions, have been observed between the endocrine-disrupting chemicals (EDCs) and ENMs, which supports the view that different types of NMs may be capable of altering the physiological activity of the endocrine system. Disruption of the endocrine system leads to hormonal imbalance, which may influence the development and pathogenesis of metabolic disorders, particularly type 2 diabetes mellitus (T2DM). Evidence from many in vitro, in vivo and epidemiological studies, suggests that ENMs generally exert deleterious effects on the molecular/hormonal pathways and the organ systems involved in the pathogenesis of T2DM. However, the available data from several such studies are not congruent, especially because of discrepancies in study design, and therefore need to be carefully examined before drawing meaningful inferences. In this review, we discuss the outcomes of ENM exposure in correlation with the development of T2DM. In particular, the review focuses on the following sub-topics: (1) an overview of the sources of human exposure to NMs, (2) systems involved in the uptake of ENMs into human body, (3) endocrine disrupting engineered nanomaterials (EDENMs) and mechanisms underlying the pathogenesis of T2DM, (4) evidence of the role of EDENMs in the pathogenesis of T2DM from in vitro, in vivo and epidemiological studies, and (5) conclusions and perspectives.

Organotins in obesity and associated metabolic disturbances

The objective of the present study was to review the mechanisms of organotin-induced adipogenesis, obesity, and associated metabolic disturbances. Peroxisome proliferator-activated receptor γ (PPARγ) and retinoid X receptor α (RXRα) activation is considered as the key mechanism of organotin-induced adipogenesis. Particularly, organotin exposure results in increased adipogenesis both in cell and animal models. Moreover, transgenerational inheritance of organotin-induced obese phenotype was demonstrated in vivo. At the same time, the existing data demonstrate that organotin compounds (OTCs) induces aberrant expression of PPARγ-targeted genes, resulting in altered of adipokine, glucose transporter, proinflammatory cytokines levels, and lipid and carbohydrate metabolism. The latter is generally characterized by hyperglycemia and insulin resistance. Other mechanisms involved in organotin-induced obesity may include estrogen receptor and corticosteroid signaling, altered DNA methylation, and gut dysfunction. In addition to cellular effects, organotin exposure may also affect neural circuits of appetite regulation, being characterized by neuropeptide Y (NPY) up-regulation in parallel with of pro-opiomelanocortin (POMC), Agouti-related protein (AgRP), and cocaine and amphetamine regulated transcript (CART) down-regulation in the arcuate nucleus. These changes result in increased orexigenic and reduced anorexigenic signaling, leading to increased food intake. The existing data demonstrate that organotins are potent adipogenic agents, however, no epidemiologic studies have been performed to reveal the association between organotin exposure and obesity and the existing indirect human data are contradictory.

'Green' synthesis of metals and their oxide nanoparticles: applications for environmental remediation

In materials science, “green” synthesis has gained extensive attention as a reliable, sustainable, and eco-friendly protocol for synthesizing a wide range of materials/nanomaterials including metal/metal oxides nanomaterials, hybrid materials, and bioinspired materials. As such, green synthesis is regarded as an important tool to reduce the destructive effects associated with the traditional methods of synthesis for nanoparticles commonly utilized in laboratory and industry. In this review, we summarized the fundamental processes and mechanisms of “green” synthesis approaches, especially for metal and metal oxide [e.g., gold (Au), silver (Ag), copper oxide (CuO), and zinc oxide (ZnO)] nanoparticles using natural extracts. Importantly, we explored the role of biological components, essential phytochemicals (e.g., flavonoids, alkaloids, terpenoids, amides, and aldehydes) as reducing agents and solvent systems. The stability/toxicity of nanoparticles and the associated surface engineering techniques for achieving biocompatibility are also discussed. Finally, we covered applications of such synthesized products to environmental remediation in terms of antimicrobial activity, catalytic activity, removal of pollutants dyes, and heavy metal ion sensing.

Review of the effects of silver nanoparticle exposure on gut bacteria

Gut bacteria are involved in regulating several important physiological functions in the host, and intestinal dysbacteriosis plays an important role in several human diseases, including intestinal, metabolic and autoimmune disorders. Although silver nanoparticles (AgNPs) are increasingly being incorporated into medical and consumer products due to their unique physicochemical properties, studies have indicated their potential to affect adversely the gut bacteria. In this review, we focus on the biotoxicological effects of AgNPs entering the gastrointestinal tract and the relationship of these effects with important nanoscale properties. We discuss in detail the mechanisms underlying the bactericidal toxicity effects of AgNPs and explore the relationships between AgNPs, gut bacteria and disease. Finally, we highlight the need to focus on the negative effects of AgNPs usage to facilitate appropriate development of these particles.

PLGA nanoparticles with multiple modes are a biologically safe nanocarrier for mammalian development and their offspring

Nano-sized particles (NPs) of various materials have been extensively used as therapeutic and diagnostic agents, drug delivery systems, and biomedical devices. However, the biological impacts of NP exposure during early embryogenesis on following development and next generations have not been investigated. Here, we demonstrated that polylactic-co-glycolic acid (PLGA)-NPs were not toxic and did not perturb development of preimplantation mouse embryos in vitro. Moreover, subsequent fetal development in vivo after embryo transfer proceeded normally and healthy pups were born without any genetic aberrations, suggesting biosafety of PLGA-NPs during developmental processes. TRITC-labeled PLGA-NPs, named TRITC nano-tracer (TnT) were used to visualize the successful delivery of the NPs into sperms, oocytes and early embryos. Various molecular markers for early embryogenesis demonstrated that TnT treatment at various developmental stages did not compromise embryo development to the blastocyst. mRNA-Seq analyses reinforced that TnT treatment did not significantly affect mRNA landscapes of blastocysts which undergo embryo implantation critical for following developmental processes. Moreover, when 2-cell embryos exposed to TnT were transferred into pseudopregnant recipients, healthy offspring were born without any distinct morphologic and chromosomal abnormalities. TnT treatment did not affect the sex ratio of the exposed embryos after birth. When mated with male mice, female mice that were exposed to TnT during early embryogenesis produced a comparable number of pups as control females. Furthermore, the phenotypes of the offspring of mice experienced TnT at their early life clearly demonstrated that TnT did not elicit any negative transgenerational effects on mammalian development.

Tributyltin Inhibits Neural Induction of Human Induced Pluripotent Stem Cells

Tributyltin (TBT), one of the organotin compounds, is a well-known environmental pollutant. In our recent study, we reported that TBT induces mitochondrial dysfunction, in human-induced pluripotent stem cells (iPSCs) through the degradation of mitofusin1 (Mfn1), which is a mitochondrial fusion factor. However, the effect of TBT toxicity on the developmental process of iPSCs was not clear. The present study examined the effect of TBT on the differentiation of iPSCs into the ectodermal, mesodermal, and endodermal germ layers. We found that exposure to nanomolar concentration of TBT (50 nM) selectively inhibited the induction of iPSCs into the ectoderm, which is the first step in neurogenesis. We further assessed the effect of TBT on neural differentiation and found that it reduced the expression of several neural differentiation marker genes, which were also downregulated by Mfn1 knockdown in iPSCs. Taken together, these results indicate that TBT induces developmental neurotoxicity via Mfn1-mediated mitochondrial dysfunction in iPSCs.

Comparative evaluation of half-maximum inhibitory concentration and cytotoxicity of silver nanoparticles and multiwalled carbon nanotubes using buffalo bull spermatozoa as a cell model

There is a dearth of information regarding the safety of silver nanoparticles (Ag NPs) and multiwalled carbon nanotubes (MWCNTs) with respect to their impact on human/animal health and the environment. This study aimed to determine the half-maximum inhibitory concentration (IC50) of Ag NPs and MWCNTs by employing different doses and time interval combinations in buffalo bull spermatozoa. Semen samples containing 100 million spermatozoa each were incubated with 1, 10, 25, 50, 75 and 100 µg/mL of Ag NPs and MWCNTs at 37°C for 30, 60 and 120 min. Sperm viability was monitored by the MTT assay and eosin–nigrosin staining followed by estimation of IC50 values using correlation–regression analysis. Spermatozoa treated with IC50 doses of Ag NPs and MWCNTs were also assessed for different sperm functionality parameters including oxidative stress and membrane integrity. These parameters were observed to be significantly affected in treated spermatozoa compared with the controls. We concluded that both nanomaterials showed cytotoxicity, mediated principally via oxidative stress. This work has provided valuable toxicological information that will serve as a benchmark for future studies aimed at safe use of nanomaterials.

Guidance on risk assessment of the application of nanoscience and nanotechnologies in the food and feed chain: Part 1, human and animal health

The European Food Safety Authority has produced this Guidance on human and animal health aspects (Part 1) of the risk assessment of nanoscience and nanotechnology applications in the food and feed chain. It covers the application areas within EFSA's remit, e.g. novel foods, food contact materials, food/feed additives and pesticides. The Guidance takes account of the new developments that have taken place since publication of the previous Guidance in 2011. Potential future developments are suggested in the scientific literature for nanoencapsulated delivery systems and nanocomposites in applications such as novel foods, food/feed additives, biocides, pesticides and food contact materials. Therefore, the Guidance has taken account of relevant new scientific studies that provide more insights to physicochemical properties, exposure assessment and hazard characterisation of nanomaterials. It specifically elaborates on physicochemical characterisation of nanomaterials in terms of how to establish whether a material is a nanomaterial, the key parameters that should be measured, the methods and techniques that can be used for characterisation of nanomaterials and their determination in complex matrices. It also details the aspects relating to exposure assessment and hazard identification and characterisation. In particular, nanospecific considerations relating to in vivo/in vitro toxicological studies are discussed and a tiered framework for toxicological testing is outlined. It describes in vitro degradation, toxicokinetics, genotoxicity as well as general issues relating to testing of nanomaterials. Depending on the initial tier results, studies may be needed to investigate reproductive and developmental toxicity, immunotoxicity, allergenicity, neurotoxicity, effects on gut microbiome and endocrine activity. The possible use of read‐across to fill data gaps as well as the potential use of integrated testing strategies and the knowledge of modes/mechanisms of action are also discussed. The Guidance proposes approaches to risk characterisation and uncertainty analysis, and provides recommendations for further research in this area.

This publication is linked to the following EFSA Supporting Publications article: http://onlinelibrary.wiley.com/doi/10.2903/sp.efsa.2018.EN-1430/full

Assessment of occupational exposure to engineered nanomaterials in research laboratories using personal monitors

Exposure assessment is a key stage in the risk assessment/management of engineered nanomaterials. Although different sampling strategies and instruments have been used to define the occupational exposure to nano-scale materials, currently there is no international consensus regarding measurement strategy, metrics and limit values. In fact, the assessment of individual exposure to engineered nanomaterials remains a critical issue despite recent innovative developments in personal monitors and samplers. Hence, we used several of these instruments to evaluate the workers' personal exposure in a large research laboratory where engineered nanomaterials are produced, handled, and characterized in order to provide input data for nanomaterial exposure assessment strategies and future epidemiological studies. The results obtained using personal monitors showed that the workplace concentrations of engineered nanomaterials (lung deposited surface area and particle number concentrations) were quite low in all the different workplaces monitored, with short spikes during the execution of some specific job tasks. The sampling strategy was been adopted on the basis of an Organisation for Economic Cooperation and Development (OECD) suggestion for a tiered approach and was found to be suitable for determining the individual exposure and for identifying possible sources of emission, even those with very low emission rates. The use of these instruments may lead to a significant improvement not only in the exposure assessment stage but, more generally, in the entire risk assessment and management process.

Potential Health Risk of Endocrine Disruptors in Construction Sector and Plastics Industry: A New Paradigm in Occupational Health

Endocrine disruptors (EDs) belong to large and diverse groups of agents that may cause multiple biological effects associated with, for example, hormone imbalance and infertility, chronic diseases such as diabetes, genome damage and cancer. The health risks related with the exposure to EDs are typically underestimated, less well characterized, and not regulated to the same extent as, for example, carcinogens. The increased production and utilization of identified or suspected EDs in many different technological processes raises new challenges with respect to occupational exposure settings and associated health risks. Due to the specific profile of health risk, occupational exposure to EDs demands a new paradigm in health risk assessment, redefinition of exposure assessment, new effects biomarkers for occupational health surveillance and definition of limit values. The construction and plastics industries are among the strongest economic sectors, employing millions of workers globally. They also use large quantities of chemicals that are known or suspected EDs. Focusing on these two industries, this short communication discusses: (a) why occupational exposure to EDs needs a more specific approach to occupational health risk assessments, (b) identifies the current knowledge gaps, and (c) identifies and gives a rationale for a future occupational health paradigm, which will include ED biomarkers as a relevant parameter in occupational health risk assessment, surveillance and exposure prevention.

Protein profiling as early detection biomarkers for TiO2 nanoparticle toxicity in Daphnia magna

The mode of action for nanoparticle (NP) toxicity in aquatic organisms is not yet fully understood. In this work, a strategy other than toxicity testing was applied to Daphnia magna exposed to TiO₂-NPs: the use of nuclear microscopy and the assessment of protein profile. D. magna is a keystone species broadly used as a model system in ecotoxicology. Titanium (Ti) was found in the D. magna digestive tract, mainly in the gut. The penetration of Ti into the epithelial region was greater at higher exposure levels and also observed in eggs in the brood pouch. The protein profile of individuals exposed to different concentrations showed that 2.8 and 5.6 mg/L TiO₂-NP concentrations induced an over-expression of the majority of proteins, in particular proteins with molecular weight of ∼120, 85 and 15 kDa, while 11.2 mg/L TiO₂-NP had an inhibitory effect on protein expression. The Matrix-assisted laser desorption ionization with tandem time of flight mass spectrometry (MALDI-TOF/TOF MS) analysis of these proteins consistently identified them as vitellogenin (Vtg)-like proteins, associated with enzymes involved in redox balance. These results indicate that Vtg-like proteins are up-regulated in D. magna exposed to TiO₂-NPs. Vitellogenesis is associated with the reproduction system, suggesting that TiO₂-NP exposure can impair reproduction by affecting this process. The precise mode of action of TiO₂-NPs is still unclear and the results from this study are a first attempt to identify specific proteins as potential markers of TiO₂-NP toxicity in D. magna, providing useful information for future research.

Nanoparticle Exposure and Hormetic Dose-Responses: An Update

The concept of hormesis, as an adaptive response of biological systems to moderate environmental challenges, has raised considerable nano-toxicological interests in view of the rapid pace of production and application of even more innovative nanomaterials and the expected increasing likelihood of environmental and human exposure to low-dose concentrations. Therefore, the aim of this review is to provide an update of the current knowledge concerning the biphasic dose-responses induced by nanoparticle exposure. The evidence presented confirmed and extended our previous findings, showing that hormesis is a generalized adaptive response which may be further generalized to nanoscale xenobiotic challenges. Nanoparticle physico-chemical properties emerged as possible features affecting biphasic relationships, although the molecular mechanisms underlining such influences remain to be fully understood, especially in experimental settings resembling long-term and low-dose realistic environmental exposure scenarios. Further investigation is necessary to achieve helpful information for a suitable assessment of nanomaterial risks at the low-dose range for both the ecosystem function and the human health.

Evidence of the Possible Harm of Endocrine-Disrupting Chemicals in Humans: Ongoing Debates and Key Issues

Evidence has emerged that endocrine-disrupting chemicals (EDCs) can produce adverse effects, even at low doses that are assumed safe. However, systemic reviews and meta-analyses focusing on human studies, especially of EDCs with short half-lives, have demonstrated inconsistent results. Epidemiological studies have insuperable methodological limitations, including the unpredictable net effects of mixtures, non-monotonic dose-response relationships, the non-existence of unexposed groups, and the low reliability of exposure assessment. Thus, despite increases in EDC-linked diseases, traditional epidemiological studies based on individual measurements of EDCs in bio-specimens may fail to provide consistent results. The exposome has been suggested as a promising approach to address the uncertainties surrounding human studies, but it is never free from these methodological issues. Although exposure to EDCs during critical developmental periods is a major concern, continuous exposure to EDCs during non-critical periods is also harmful. Indeed, the evolutionary aspects of epigenetic programming triggered by EDCs during development should be considered because it is a key mechanism for developmental plasticity. Presently, living without EDCs is impossible due to their omnipresence. Importantly, there are lifestyles which can increase the excretion of EDCs or mitigate their harmful effects through the activation of mitohormesis or xenohormesis. Effectiveness of lifestyle interventions should be evaluated as practical ways against EDCs in the real world.

Palladium nanoparticle effects on endocrine reproductive system of female rats

The widespread industrial application of nanomaterials (NMs) has dramatically increased the likelihood of environmental and occupational exposure of humans to such xenobiotics. This issue, together with the increasing public health interest in understanding the effects of chemicals on endocrine system, encouraged to investigate the disruptive potential of NMs on the endocrine function. Therefore, the aim of this study was to evaluate the effects of palladium nanoparticles (Pd-NPs) on the female reproductive system of Wistar rats, intravenously exposed to different doses (0.12, 1.2, and 12 µg/kg), through the assessment of possible quantitative changes in the serum concentrations of several sex hormones. Our results demonstrated that the highest exposure doses significantly reduced the estradiol and testosterone concentrations, while increased the luteinizing hormone levels in treated animals compared to controls. Such alterations are indicative for an abnormal reproductive axis function. However, further investigations are needed to clarify the role of the different NP physicochemical properties in determining such effects, and possible underlining molecular mechanisms, as well as their relevance for the development of diseases in the female reproductive system. Overall, this may be helpful to define accurate risk assessment and management strategies to protect the health of the general and occupational populations exposed to Pd-NPs.

The adverse effects of chronic low-dose exposure to nonylphenol on type 2 diabetes mellitus in high sucrose-high fat diet-treated rats

OBJECTIVES

Although it has been shown that exposure to environmental endocrine disruptors (EDCs) has been implicated as a potential risk factor for metabolic disease, information on adverse effect of chronic low-dose exposure to nonylphenol (NP), on the development and progress of type 2 diabetes mellitus (T2DM) is scarce. NP, as an EDC, is a ubiquitous degradation product of nonylphenol polyethoxylate (NPE) that is primarily used in cleaning and industrial processes.

METHOD

Eighty Sprague-Dawley rats were assigned into 8 groups (n = 10 per group): rats fed a normal-diet (ND) as the control (C-ND); rats fed a normal diet and were gavaged with NP at a dose level of 0.02 μg/kg/day (NP-L-ND), 0.2 μg/kg/day (NP-M-ND) or 2 μg/kg/day (NP-H-ND), respectively; rats fed a high-sucrose/high-fat diet (HSHFD) as the HSHFD control (C-HSHFD); rats fed a HSHFD and were gavaged with NP at a dose level of 0.02 μg/kg/day (NP-L-HSHFD), 0.2 μg/kg/day (NP-M-HSHFD) or 2 μg/kg/day (NP-H-HSHFD), respectively.

RESULT

On day 180, the rats in the groups treated with NP-M-HSHFD and NP-H-HSHFD showed significant increases in body weight (p < 0.05) in comparison with the C-ND group. Fast blood glucose (FBG) level in the NP-M-HSHFD and NP-H-HSHFD groups was higher than that in the C-ND group (F = 96.17, p < 0.001). The fast serum insulin (FINS) level of rats was lower in both the NP-M-HSHFD and NP-H-HSHFD groups compared with the C-ND group (F = 145.56, p < 0.001). Serum leptin (LEP) level in both the NP-M-HSHFD and NP-H-HSHFD groups was lower when compared with the C-ND group (F = 34.62, p < 0.001). The effect of NP at the dose level of 0.2 μg/kg/day on FBG, serum FINS and LEP levels in rats was greatest among the treatment groups (p < 0.05). Oral glucose tolerance test showed increased area under the curve (AUC) in treatment groups at week 12 (p < 0.05). A decrease of pancreatic islet numbers and size was exhibited in the pancreatic tissue of NP-M-HSHFD and NP-H-HSHFD treated rats compared with C-ND treated rats. Co-exposure to NP and HSHFD causes inflammatory changes histologically.

CONCLUSION

Chronic low-dose exposure to NP might induce impaired glucose tolerance, which further lead to insulin resistance, and pancreatic β cell insulin secretion deficiency, ultimately increase the risk of T2DM. Moreover, additive toxic effects of NP and HSHFD on pancreatic beta-cell function and glucose metabolism have been identified in rats as well.

The assessment of metabolite alteration induced by -OH functionalized multi-walled carbon nanotubes in mice using NMR-based metabonomics

Introduction: There is a fundamental need to characterize multiwalled carbon nanotubes (MWCNTs) toxicity to guarantee their safe application. Functionalized MWCNTs have recently attracted special interest in order to enhance biocompatibility. The aim of the current work was to study the underlying toxicity mechanism of the -OH-functionalized MWCNTs (MWCNTs-OH), using the powerful NMR-based metabonomics technique. Methods: Following intraperitoneal single-injection of mice with 3 doses of MWCNTs-OH and one control, samples were collected at four time points during 22-days for NMR, biochemistry, and histopathology analysis. Metabolome profiling and pathway analysis were implemented by chemometrics tools and metabolome databases. Results: Based on the 1H-NMR data, metabolic perturbation induced by MWCNTs-OH were characterized by altered levels of steroid hormones, including elevated androgens, estrogens, corticosterone, and aldosterone. Moreover, increased L-lysine, aminoadipate, taurine and taurocholic acid and decreased biotin were observed in the high-dose group (1 mg.kg-1 B.W.) compared to the control. The findings also indicated that steroid hormone biosynthesis, lysine biosynthesis, and biotin metabolism are the most affected pathways by MWCNTs-OH. Conclusion: These pathways can reflect perturbation of energy, amino acids, and fat metabolism, as well as oxidative stress. The data obtained by biochemistry, metabonomics, and histopathology were in good agreement, proving that MWCNTs-OH was excreted within 24 h, through the biliary pathway.

Recent Advances in Antimicrobial Hydrogels Containing Metal Ions and Metals/Metal Oxide Nanoparticles

Recently, the rapid emergence of antibiotic-resistant pathogens has caused a serious health problem. Scientists respond to the threat by developing new antimicrobial materials to prevent or control infections caused by these pathogens. Polymer-based nanocomposite hydrogels are versatile materials as an alternative to conventional antimicrobial agents. Cross-linking of polymeric materials by metal ions or the combination of polymeric hydrogels with nanoparticles (metals and metal oxide) is a simple and effective approach for obtaining a multicomponent system with diverse functionalities. Several metals and metal oxides such as silver (Ag), gold (Au), zinc oxide (ZnO), copper oxide (CuO), titanium dioxide (TiO₂) and magnesium oxide (MgO) have been loaded into hydrogels for antimicrobial applications. The incorporation of metals and metal oxide nanoparticles into hydrogels not only enhances the antimicrobial activity of hydrogels, but also improve their mechanical characteristics. Herein, we summarize recent advances in hydrogels containing metal ions, metals and metal oxide nanoparticles with potential antimicrobial properties.

Colloid particle formulations for antimicrobial applications

Colloidal particles are being extensively studied in various antimicrobial applications due to their small size to volume ratio and ability to exhibit a wide spectrum of antibacterial, antifungal, antialgal and antiviral action. The present review focuses on various nanoparticles (NPs) of inorganic, organic and hybrid materials, and discusses some of the methods for their preparation as well as mechanisms of their antimicrobial action. We consider the antimicrobial applications of metal oxide nanoparticles (ZnO, MgO, CuO, Cu₂O, Al₂O₃, TiO₂, CeO₂ and Y₂O₃), metal nanoparticles (NPs), such as copper, silver and gold, metal hydroxide NPs such as Mg(OH)₂ as well as hybrid NPs made from biodegradable materials, such as chitosan, lignin and dextran, loaded with other antimicrobial agents. Recent developments for targeted delivery of antimicrobials by using colloid antibodies for microbial cell shape and surface recognition are also discussed. We also consider recent advances in the functionalization of nanoparticles and their potential antimicrobial applications as a viable alternative of conventional antibiotics and antiseptic agents which can help to tackle antimicrobial resistance. The review also covers the recently developed environmentally benign NPs (EbNPs) as a "safer-by-design" green chemistry solution of the post use fate of antimicrobial nanomaterials.

Nanotechnology in agriculture: Opportunities, toxicological implications, and occupational risks

Nanotechnology has the potential to make a beneficial impact on several agricultural, forestry, and environmental challenges, such as urbanization, energy constraints, and sustainable use of resources. However, new environmental and human health hazards may emerge from nano-enhanced applications. This raises concerns for agricultural workers who may become primarily exposed to such xenobiotics during their job tasks. The aim of this review is to discuss promising solutions that nanotechnology may provide in agricultural activities, with a specific focus on critical aspects, challenging issues, and research needs for occupational risk assessment and management in this emerging field. Eco-toxicological aspects were not the focus of the review. Nano-fertilizers, (nano-sized nutrients, nano-coated fertilizers, or engineered metal-oxide or carbon-based nanomaterials per se), and nano-pesticides, (nano-formulations of traditional active ingredients or inorganic nanomaterials), may provide a targeted/controlled release of agrochemicals, aimed to obtain their fullest biological efficacy without over-dosage. Nano-sensors and nano-remediation methods may detect and remove environmental contaminants. However, limited knowledge concerning nanomaterial biosafety, adverse effects, fate, and acquired biological reactivity once dispersed into the environment, requires further scientific efforts to assess possible nano-agricultural risks. In this perspective, toxicological research should be aimed to define nanomaterial hazards and levels of exposure along the life-cycle of nano-enabled products, and to assess those physico-chemical features affecting nanomaterial toxicity, possible interactions with agro-system co-formulants, and stressors. Overall, this review highlights the importance to define adequate risk management strategies for workers, occupational safety practices and policies, as well as to develop a responsible regulatory consensus on nanotechnology in agriculture.

Physiological and histological effects of (zinc and iron) oxide nanoparticles on some fertility parameters in female mice

Nowadays nanoparticles have widespread application in various industriesbecause of their special and unique features, there are many studies in sideeffects of nanomaterial. This study done by 40 white female mice withevery other day intraperitoneally injection of low and high doses of both ofZnO kg of body weight) and FeOnanoparticles (5 and 40 mg/kg). After a 15 days period, the mice weresacrificed and blood samples were collected for hormone analysis, andtissue samples for morphometric studies.Statistical Analysis shows significant differences in LH, Estrogen,Progesterone hormone levels between groups, while there are insignificantdifferences in Follicle stimulating hormone (FSH) level between thegroups compared with its level in the control group.The results also show that the highest level of LH reach 7.2 mIU/ml in thegroups treated with low dose of zinc oxide, the highest level of FSH reach4.58 mIU/ml in the groups treated with low dose of zinc oxide, the highestlevel of Estrogen hormone reach 69.5 ng/ml in the groups treated with lowof dose zinc oxide and the highest level of Progesterone reach 1.9 ng/ml inthe groups treated with high dose iron oxide. We conclude from the resultsthat the low doses of ZnO has benefits in increasing fertility through highlevel of reproductive hormones, while the high levels of nanoparticlesreduce fertility and there is a relation between FeO nanoparticles andprogesterone levels which may need more future studies.Morphometric study of the ovary show increase in Follicular stagesnumber range in the group treated with Low dose ZnO in compare with itsrange in the control groups. The lower range was belong to the grouptreated with the high dose of FeO. No significant differences has beenfound in the diameter mean of the different follicular phases between thegroup treated with low dose of ZnO NPs in compared with the controlgroup. High dose of ZnO NPs cause significant increase in the diametermean of Primordial follicles in compared with the control group. Low andhigh dose FeO NPs treated groups show significant reduction in thediameter mean of the different follicular phases in compared with thecontrol group.

Adverse eff ects of polymeric nanoparticle poly(ethylene glycol)- block-polylactide methyl ether (PEG-b-PLA) on steroid hormone secretion by porcine granulosa cells

Objectives. Development of nanoparticles (NPs) for biomedical applications, including medical imaging and drug delivery, is currently undergoing a dramatic expansion. Diverse effects of different type NPs relating to mammalian reproductive tissues have been demonstrated. Th e objective of this study was to explore the in vitro effects of polymeric nanoparticle poly(ethylene glycol)-blockpolylactide methyl ether (PEG-b-PLA NPs) on functional state and viability of ovarian granulosa cells (GCs), which play an important role in maintaining ovarian function and female fertility.

Methods. The GCs isolated from porcine ovarian follicles were incubated with the different concentrations of PEG-b-PLA NPs (PEG average Mn=350 g/mol and PLA average Mn=1000 g/mol; 0.2-100 μg/ml) or poly(ethylene glycol) with an average molecular weight of 300 (PEG-300; 0.2- 40 mg/ml) in the presence or absence of stimulators, follicle-stimulating hormone (FSH; 1 μg/ml), androstenedione (100 nM), forskolin (10 μM) or 8Br-cAMP (100 μM), for different time periods (24, 48, 72 h). At the end of the incubation, progesterone and estradiol levels produced by GCs were measured in the culture media by radioimmunoassay. Th e viability of GCs was determined by the method using a colorimetric assay with MTT.

Results. Treatment of GCs with PEG-b-PLA NPs induced a significant decrease in basal as well as FSH-stimulated progesterone secretion above the concentration of 20 and 4 μg/ml, respectively. Moreover, PEG-b-PLA NPs reduced forskolin-stimulated, but not cAMP-stimulated progesterone production by GCs. A dose-dependent inhibition of androstenedione-stimulated estradiol release by GCs was found by the action of PEG-b-PLA NPs. Incubation of GCs with PEG-300 significantly inhibited basal as well as FSH-stimulated progesterone secretion above the concentration of 40 mg/ml. PEG-b-PLA NPs and PEG-300 significantly reduced the viability of GCs at the highest tested concentrations (100 μg/ml and 40 mg/ml, respectively).

Conclusions. The obtained results indicate that polymeric NPs PEG-b-PLA might induce alterations in steroid hormone production by ovarian GCs and thereby could modify reproductive functions.

Hormonal and organ-specific dysfunction induced by the interaction between titanium dioxide nanoparticles and salicylic acid in male mice

BACKGROUND

Nanomaterials coating gained much concern in orthopedic implants and cosmetics. Drug combination may be a promising strategy for treating multi-factorial diseases. Titanium dioxide (TDN) nanoparticles are being widely used in many industries as well as in medicine and pharmacology. Therefore, increased human and environmental exposure can be expected, which has put TDN under toxicological scrutiny, and it is necessary to address the potential health and safety implications of nanomaterials used in nanomedicine. The toxicity of titanium oxide nanoparticles (TDN) and salicylic acid (SA) separately or in combination was studied for 21 days.

METHODS

The liver and kidney biomarker were determined, and hormones and oxidative stress levels were detected in mice.

RESULTS

The intraperitoneal (i.p.) injection of TDN and SA in combination had a potential toxicological effect on major organs and hormonal homeostasis of mice. TDN and SA could antagonistically interact to affect the liver and kidney functions. No synergistic damage was observed in the liver function of mice that were treated with both TDN and SA as compared to the SA group. TDN acted as a synergistic agent to SA in the case of total cholesterol and total proteins levels. SA acted as antagonistic to the effect of TDN when injected together in mice because the effect on kidney functions is less than that predicted on the basis of the additive. The effect of co-administration of SA and TDN on the following hormones; triiodothyronine, thyroxine, estradiol II and insulin various among additive, potentiation, antagonistic and no effect, respectively as compared to TDN group. The interaction of TDN and SA was also found to induce oxidative stress as indicated by the increase in lipid peroxidation (LPO) levels. The decrease in the level of the reduced glutathione in the co-treated group indicated that there were no synergistic damages. SA and TDN co-administration could induce a potential increase in LPO levels in liver, kidney, and spleen but not in heart tissue. These results have not suggested that TDN and SA have a synergistic sub-chronic toxicity in mice after i.p. administration. SA may decrease the toxicity of TDN to some degree that could be related to the potentiation chemical reaction between SA and TDN.

CONCLUSIONS

Our results suggested that the damage observed in mice treated with TDN and SA is organ-specific and associated with hormonal homeostasis and oxidative damage.

Environmental epigenomics: Current approaches to assess epigenetic effects of endocrine disrupting compounds (EDC's) on human health

Environmental Epigenomics is a developing field to study the epigenetic effect on human health from exposure to environmental factors. Endocrine disrupting chemicals have been detected primarily in pharmaceutical drugs, personal care products, food additives, and food containers. Exposure to endocrine-disrupting chemicals (EDCs) has been associated with a high incidence and prevalence of many endocrine-related disorders in humans. Nevertheless, further evidence is needed to establish a correlation between exposure to EDC and human disorders. Conventional detection of EDCs is based on chemical structure and concentration sample analysis. However, substantial evidence has emerged, suggesting that cell exposure to EDCs leads to epigenetic changes, independently of its chemical structure with non-monotonic low-dose responses. Consequently, a paradigm shift in toxicology assessment of EDCs is proposed based on a comprehensive review of analytical techniques used to evaluate the epigenetic effects. Fundamental insights reported elsewhere are compared in order to establish DNA methylation analysis as a viable method for assessing endocrine disruptors beyond the conventional study approach of chemical structure and concentration analysis.

A brief review on the application of nanoparticle enclosed herbal medicine for the treatment of infective endocarditis

Herbal medicines have been routinely employed all over the world dated back from the ancient time and have been identified by patients and physicians for their excellent therapeutic value as they have lower adverse effects when compared with the modern medicines. Phytotherapeutics requires a scientific technique to deliver the active herbal extract in a controlled manner to avoid repeated administration and increase patient compliance. This can be reached by fabricating a novel drug delivery systems (NDDS) for herbal components. NDDSs does not only decrease the repeated dose to overcome ineffectiveness, but also help to increase potency by decreasing toxicity and elevating drug bioavailability. Nano-sized DDS of herbal drugs have a potential application for improving the activity and countering the problems related to herbal medicines. Hence, application of nanocarriers as an NDDS in the traditional herbal medicine system is important to treat more chronic diseases like infectious endocarditis.

Effect of Molybdenum Nanoparticles on Blood Cells, Liver Enzymes, and Sexual Hormones in Male Rats

Despite an increasing surge in application of nanoparticles in industries, there is a serious lack of information concerning their impact on human health and the environment. The present study investigated effects of molybdenum nanoparticles (Mo NPs) injected intraperitoneally into Sprague-Dawley rats at different doses of Mo NPs (5, 10, and 15 mg/kg BW per day) during a period of 28 days. Hematological and biochemical parameters as well as sexual hormones and histopathological examinations of the liver and testis were assessed and compared with control group. The results showed that the serum levels of testosterone decreased significantly in both groups of 10 and 15 mg (Mo NPs)/kg BW in comparison with the control group (p < 0.05). However, there were insignificant differences observed in luteinizing hormone (LH) levels and hematological parameters when compared with the control group (p > 0.05). The results of liver enzymes showed that serum levels of aspartate aminotransferase (AST) decreased significantly in both dosage groups of 5 and 10 mg/kg BW (Mo NPs) when compared with the control group (p < 0.05), and significant decrease obtained in lactate dehydrogenase (LDH) levels at dose of 5 mg/kg BW in comparison with the control group (p < 0.05). The histopathological examination of testis showed a decrease in number of Leydig cells. Also, the number of chronic inflammatory cells increased in portal triad and parenchyma in liver tissue of rats exposed to Mo NPs.

Recent Nanotechnology Approaches for Prevention and Treatment of Biofilm-Associated Infections on Medical Devices

Bacterial colonization in the form of biofilms on surfaces causes persistent infections and is an issue of considerable concern to healthcare providers. There is an urgent need for novel antimicrobial or antibiofilm surfaces and biomedical devices that provide protection against biofilm formation and planktonic pathogens, including antibiotic resistant strains. In this context, recent developments in the material science and engineering fields and steady progress in the nanotechnology field have created opportunities to design new biomaterials and surfaces with anti-infective, antifouling, bactericidal, and antibiofilm properties. Here we review a number of the recently developed nanotechnology-based biomaterials and explain underlying strategies used to make antibiofilm surfaces.

Disposition of intravenously or orally administered silver nanoparticles in pregnant rats and the effect on the biochemical profile in urine

Few investigations have been conducted on the disposition and fate of silver nanoparticles (AgNP) in pregnancy. The distribution of a single dose of polyvinylpyrrolidone (PVP)-stabilized AgNP was investigated in pregnant rats. Two sizes of AgNP, 20 and 110 nm, and silver acetate (AgAc) were used to investigate the role of AgNP diameter and particle dissolution in tissue distribution, internal dose and persistence. Dams were administered AgNP or AgAc intravenously (i.v.) (1 mg kg^-1 ) or by gavage (p.o.) (10 mg kg^-1 ), or vehicle alone, on gestation day 18 and euthanized at 24 or 48 h post-exposure. The silver concentration in tissues was measured using inductively-coupled plasma mass spectrometry. The distribution of silver in dams was influenced by route of administration and AgNP size. The highest concentration of silver (μg Ag g^-1 tissue) at 48 h was found in the spleen for i.v. administered AgNP, and in the lungs for AgAc. At 48 h after p.o. administration of AgNP, the highest concentration was measured in the cecum and large intestine, and for AgAc in the placenta. Silver was detected in placenta and fetuses for all groups. Markers of cardiovascular injury, oxidative stress marker, cytokines and chemokines were not significantly elevated in exposed dams compared to vehicle-dosed control. NMR metabolomics analysis of urine indicated that AgNP and AgAc exposure impact the carbohydrate, and amino acid metabolism. This study demonstrates that silver crosses the placenta and is transferred to the fetus regardless of the form of silver. Copyright © 2016 John Wiley & Sons, Ltd.

Pulmonary exposure to cellulose nanocrystals caused deleterious effects to reproductive system in male mice

Over the past several years there has been an increased number of applications of cellulosic materials in many sectors, including the food industry, cosmetics, and pharmaceuticals. However, to date, there are few studies investigating the potential adverse effects of cellulose nanocrystals (CNC). The objective of this study was to determine long-term outcomes on the male reproductive system of mice upon repeated pharyngeal aspiration exposure to CNC. To achieve this, cauda epididymal sperm samples were analyzed for sperm concentration, motility, morphological abnormalities, and DNA damage. Testicular and epididymal oxidative damage was evaluated, as well as histopathology examination of testes. In addition, changes in levels of testosterone in testes and serum and of luteinizing hormone (LH) in serum were determined. Three months after the last administration, CNC exposure significantly altered sperm concentration, motility, cell morphology, and sperm DNA integrity. These parameters correlated with elevated proinflammatory cytokines levels and myeloperoxidase (MPO) activity in testes, as well as oxidative stress in both testes and epididymis. Exposure to CNC also produced damage to testicular structure, as evidenced by presence of interstitial edema, frequent dystrophic seminiferous tubules with arrested spermatogenesis and degenerating spermatocytes, and imbalance in levels of testosterone and LH. Taken together, these results demonstrate that pulmonary exposure to CNC induces sustained adverse effects in spermatocytes/spermatozoa, suggesting male reproductive toxicity.

Exposure to TiO2 Nanoparticles Induces Immunological Dysfunction in Mouse Testitis

Although TiO2 nanoparticles (NPs) as endocrine disruptors have been demonstrated to be able to cross the blood-testis barriers and induce reproductive toxicity in male animals, whether the reproductive toxicity of male animals due to exposure to endocrine disruptor TiO2 NPs is related to immunological dysfunction in the testis remains not well understood. This study determined whether the reproductive toxicity and immunological dysfunction induced by exposure to TiO2 NPs is associated with activation or inhibition of TAM/TLR-mediated signal pathway in mouse testis. The results showed that male mice exhibited significant reduction of fertility, infiltration of inflammatory cells, rarefaction, apoptosis, and/or necrosis of spermatogenic cells and Sertoli cells due to TiO2 NPs. Furthermore, these were associated with decreased expression of Tyro3 (-18.16 to -66.6%), Axl (-14.7 to -57.99%), Mer (-7.98 to -72.62%), and IκB (-11.25 to -63.16%), suppression of cytokine signaling (SOCS) 1 (-21.99 to -73.8%) and SOCS3 (-8.11 to -34.86%), and increased expression of Toll-like receptor (TLR)-3 (21.4-156.03%), TLR-4 (37.0-109.87%), nuclear factor-κB (14.75-69.34%), interleukin (IL)-lβ (46.15-123.08%), IL-6 (2.54-81.98%), tumor necrosis factor-α (6.95-88.39%), interferon (IFN)-α (2.54-37.25%), and IFN-β (10.19-80.56%), which are involved in the immune environment in the testis. The findings showed that reproductive toxicity of male mice induced by exposure to endocrine disruptor TiO2 NPs may be associated with biomarkers of impairment of immune environment or dysfunction of TAM/TLR3-mediated signal pathway in mouse testitis. Therefore, the potential risks to reproductive health should be attended, especially in those who are occupationally exposed to TiO2 NPs.

Endocrine activities and cellular stress responses in the marsh frog Pelophylax ridibundus exposed to cobalt, zinc and their organic nanocomplexes

Metal-containing materials are extensively used in industry, personal care products and medicine, and their release in the environment causes concern for the potential impacts on aquatic organisms. We assessed endocrine disrupting potential of N-vinyl-2-pyrrolidone-based nanoparticles (Me-PSs) containing cobalt (Co(2+)) or zinc (Zn(2+)), using the marsh frog Pelophylax ridibundus as a model. Adult males were exposed for 14 days to waterborne Co(2+) (50μg/L), Zn(2+) (100μg/L) or corresponding concentrations of Co-PS, Zn-PS, or parental polymeric compound (PS). The indices of thyroid activity, vitellogenesis, cytochrome P450-dependent monooxygenases activity (EROD) and cytotoxicity markers were evaluated. Exposure to Co(2+) led to the elevation of serum thyrotropin (TSH) and hepatic deiodinase activities accompanied by the up-regulation of EROD activity. In contrast, the action of the polymer-containing substances (Co-PS, Zn-PS and PS) as well as free Zn(2+) caused a prominent decrease of EROD activity and a decrease in serum cortisol and TSH concentrations. Exposures to Zn(2+), Zn-PS and PS upregulated vitellogenesis in males. All exposures except Co(2+) caused neurotoxicity as indicated by the depletion of cholinesterase. These results demonstrate toxicity of Co- and Zn-containing Me-PSs and their parental compounds (Zn(2+) and PS) in frogs and indicate distinct mechanisms of Co(2+) action. Broad disruption of the hormonal pathways and reduced capacity for organic xenobiotic detoxification may have deleterious impacts on amphibian populations from habitats exposed to metallorganic pollution.

Exposure to Palladium Nanoparticles Affects Serum Levels of Cytokines in Female Wistar Rats

Background

Information currently available on the impact of palladium on the immune system mainly derives from studies assessing the biological effects of palladium salts. However, in the last years, there has been a notable increase in occupational and environmental levels of fine and ultrafine palladium particles released from automobile catalytic converters, which may play a role in palladium sensitization. In this context, the evaluation of the possible effects exerted by palladium nanoparticles (Pd-NPs) on the immune system is essential to comprehensively assess palladium immunotoxic potential.

Aim

Therefore, the aim of this study was to investigate the effects of Pd-NPs on the immune system of female Wistar rats exposed to this xenobiotic for 14 days, by assessing possible quantitative changes in a number of cytokines: IL-1α, IL-2, IL-4, IL-6, IL-10, IL-12, GM-CSF, INF-γ and TNF-α.

Methods

Twenty rats were randomly divided into four exposure groups and one of control. Animals were given a single tail vein injection of vehicle (control group) and different concentrations of Pd-NPs (0.012, 0.12, 1.2 and 12 μg/kg). A multiplex biometric enzyme linked immunosorbent assay was used to evaluate cytokine serum levels.

Results

The mean serum concentrations of all cytokines decreased after the administration of 0.012 μg/kg of Pd-NPs, whereas exceeded the control levels at higher exposure doses. The highest concentration of Pd-NPs (12 μg/kg) induced a significant increase of IL-1α, IL-4, IL-6, IL-10, IL-12, GM-CSF and INF-γ compared to controls.

Discussion and Conclusions

These results demonstrated that Pd-NP exposure can affect the immune response of rats inducing a stimulatory action that becomes significant at the highest administered dose. Our findings did not show an imbalance between cytokines produced by CD4⁺ T helper (Th) cells 1 and 2, thus suggesting a generalized stimulation of the immune system with a simultaneous activation and polarization of the naïve T cells towards Th1 and Th2 phenotype.

Microvascular and mitochondrial dysfunction in the female F1 generation after gestational TiO2 nanoparticle exposure

Due to the ongoing evolution of nanotechnology, there is a growing need to assess the toxicological outcomes in under-studied populations in order to properly consider the potential of engineered nanomaterials (ENM) and fully enhance their safety. Recently, we and others have explored the vascular consequences associated with gestational nanomaterial exposure, reporting microvascular dysfunction within the uterine circulation of pregnant dams and the tail artery of fetal pups. It has been proposed (via work derived by the Barker Hypothesis) that mitochondrial dysfunction and subsequent oxidative stress mechanisms as a possible link between a hostile gestational environment and adult disease. Therefore, in this study, we exposed pregnant Sprague-Dawley rats to nanosized titanium dioxide aerosols after implantation (gestational day 6). Pups were delivered, and the progeny grew into adulthood. Microvascular reactivity, mitochondrial respiration and hydrogen peroxide production of the coronary and uterine circulations of the female offspring were evaluated. While there were no significant differences within the maternal or litter characteristics, endothelium-dependent dilation and active mechanotransduction in both coronary and uterine arterioles were significantly impaired. In addition, there was a significant reduction in maximal mitochondrial respiration (state 3) in the left ventricle and uterus. These studies demonstrate microvascular dysfunction and coincide with mitochondrial inefficiencies in both the cardiac and uterine tissues, which may represent initial evidence that prenatal ENM exposure produces microvascular impairments that persist throughout multiple developmental stages.

Nanoparticles for antimicrobial purposes in Endodontics: A systematic review of in vitro studies

INTRODUCTION

Antimicrobial nanoparticles with enhanced physiochemical properties have attracted attention as modern antimicrobials, especially in the complicated oral cavity environment. The goal of the present article is to review the current state of nanoparticles used for antimicrobial purposes in root canal infections.

METHODS

A review was conducted in electronic databases using MeSH keywords to identify relevant published literature in English. The analysis and eligibility criteria were documented according to the Preferred Reporting Items for Systematic Reviews and Meta Analysis (PRISMA-guidelines). No restrictions on publication date were imposed. Data regarding root canal disinfections, general antimicrobial mechanisms of nanoparticles, type of nanoparticles as antimicrobial agent and antimicrobial effect of nanoparticles in endodontics were collected and subjected to descriptive data analysis.

RESULTS

The literature search in electronic databases according to the inclusion criteria provided 83 titles and abstracts. Among them 15 papers were related to antimicrobial effect of nanoparticles in Endodontics. Silver nanoparticles with sustainable activity were the most studied agent for its antimicrobial behavior in root canal infection. Aided polymeric nanoparticles with photo or ultrasound, glass bioactive nanoparticles as well as Calcium derivative based nanoparticles, with improved activity in comparison with the non-nano counterparts, are of importance in infection control of dental root canal. Bioactive Non-organic nanoparticles with structural capabilities present enhanced antimicrobial activity in root canal infections.

DISCUSSION

All included studies showed an enhanced or at least equal effect of nanoparticulate systems to combat dental root canal infections compared to conventional antimicrobial procedures. However, it is crucial to understand their shortcomings and their probable cellular effects and toxicity as well as environmental effects.

Health implications of engineered nanoparticles in infants and children

BACKGROUND

The nanotechnology boom and the ability to manufacture novel nanomaterials have led to increased production and use of engineered nanoparticles (ENPs). However, the increased use of various ENPs inevitably results in their release in or the contamination of the environment, which poses significant threats to human health. In recent years, extraordinary economic and societal benefits of nanoproducts as well as their potential risks have been observed and widely debated. To estimate whether ENPs are safe from the onset of their manufacturing to their disposal, evaluation of the toxicological effects of ENPs on human exposure, especially on more sensitive and vulnerable sectors of the population (infants and children) is essential.

DATA SOURCES

Papers were obtained from PubMed, Web of Science, and Google Scholar. Literature search words included: "nanoparticles", "infants", "children", "exposure", "toxicity", and all relevant cross-references.

RESULTS

A brief overview was conducted to 1) characterize potential exposure routes of ENPs for infants and children; 2) describe the vulnerability and particular needs of infants and children about ENPs exposure; 3) investigate the current knowledge about the potential health hazards of ENPs; and 4) provide suggestions for future research and regulations in ENP applications.

CONCLUSIONS

As the manufacturing and use of ENPs become more widespread, directed and focused studies are necessary to measure actual exposure levels and to determine adverse health consequences in infants and children.

Internalization of silver nanoparticles into mouse spermatozoa results in poor fertilization and compromised embryo development

Silver nanoparticles (AgNPs) have many features that make them attractive as medical devices, especially in therapeutic agents and drug delivery systems. Here we have introduced AgNPs into mouse spermatozoa and then determined the cytotoxic effects of AgNPs on sperm function and subsequent embryo development. Scanning electron microscopy and transmission electron microscopy analyses showed that AgNPs could be internalized into sperm cells. Furthermore, exposure to AgNPs inhibited sperm viability and the acrosome reaction in a dose-dependent manner, whereas sperm mitochondrial copy numbers, morphological abnormalities, and mortality due to reactive oxygen species were significantly increased. Likewise, sperm abnormalities due to AgNPs internalization significantly decreased the rate of oocyte fertilization and blastocyst formation. Blastocysts obtained from AgNPs-treated spermatozoa showed lower expression of trophectoderm-associated and pluripotent marker genes. Overall, we propose that AgNPs internalization into spermatozoa may alter sperm physiology, leading to poor fertilization and embryonic development. Such AgNPs-induced reprotoxicity may be a valuable tool as models for testing the safety and applicability of medical devices using AgNPs.

A perspective on the developmental toxicity of inhaled nanoparticles

This paper aimed to clarify whether maternal inhalation of engineered nanoparticles (NP) may constitute a hazard to pregnancy and fetal development, primarily based on experimental animal studies of NP and air pollution particles. Overall, it is plausible that NP may translocate from the respiratory tract to the placenta and fetus, but also that adverse effects may occur secondarily to maternal inflammatory responses. The limited database describes several organ systems in the offspring to be potentially sensitive to maternal inhalation of particles, but large uncertainties exist about the implications for embryo-fetal development and health later in life. Clearly, the potential for hazard remains to be characterized. Considering the increased production and application of nanomaterials and related consumer products a testing strategy for NP should be established. Due to large gaps in data, significant amounts of groundwork are warranted for a testing strategy to be established on a sound scientific basis.

Anatase titanium dioxide nanoparticles in mice: evidence for induced structural and functional sperm defects after short-, but not long-, term exposure

Titanium dioxide (TiO 2 ) nanoparticles (TNPs) are widely used commercially and exist in a variety of products. To determine if anatase TNPs (ATNPs) in doses smaller than previously used reach the scrotum after entry in the body at a distant location and induce sperm defects, 100% ATNP (2.5 or 5 mg kg-1 body weight) was administered intraperitoneally to adult males for three consecutive days, followed by sacrifice 1, 2, 3, or 5 weeks later (long-) or 24, 48 or 120 h (short-term exposure). Transmission electron microscopy revealed the presence of ANTP in scrotal adipose tissues collected 120 h postinjection when cytokine evaluation showed an inflammatory response in epididymal tissues and fluid. At 120 h and up to 3 weeks postinjection, testicular histology revealed enlarged interstitial spaces. Significantly increased numbers of terminal deoxyribonucleotidyl transferase-mediated dUTP nick-end labeling-positive (apoptotic) germ (P = 0.002) and interstitial space cells (P = 0.04) were detected in treated males. Caudal epididymal sperm from the short-term, but not a long-term, arm showed significantly (P < 0.001) increased frequencies of flagellar abnormalities, excess residual cytoplasm (ERC), and unreacted acrosomes in treated versus controls (dose-response relationship). A novel correlation between ERC and unreacted acrosomes was uncovered. At 120 h, there were significant decreases in hyperactivated motility (P < 0.001) and mitochondrial membrane potential (P < 0.05), and increased reactive oxygen species levels (P < 0.00001) in treated versus control sperm. These results indicate that at 4-8 days postinjection, ANTP induce structural and functional sperm defects associated with infertility, and DNA damage via oxidative stress. Sperm defects were transient as they were not detected 10 days to 5 weeks postinjection.