Effects of Maternal Exposure to Cadmium Oxide Nanoparticles During Pregnancy on Maternal and Offspring Kidney Injury Markers Using a Murine Model

Cadmium Associated Preeclampsia: A Systematic Literature Review of Pregnancy and Birth Outcomes

Preeclampsia (PE), caused by multiple factors, is one of the most serious complications of pregnancy. Cadmium (Cd) is a heavy metal environmental pollutant, reproductive toxicant, and endocrine disruptor, which can increase the risk of PE. Cd toxicity due to occupational, diet, and environmental factors has worsened the risk. Studies showed elevated Cd concentration in maternal blood and placenta of PE women. However, the implicit association between Cd associated PE is still not highlighted. We systematically reviewed Cd-associated PE and its effect on pregnancy and birth outcomes. Based on "Preferred reporting items for systematic reviews and meta-analyses (PRISMA)" guidelines, eighty-six studies were identified by PubMed, Web of Science (WOS), and Scopus databases. Publications were included until October 2023 and articles screened based on our inclusion criteria. Our study identified that the exposure of controlled and uncontrolled Cd induces PE, which negatively affects pregnancy and birth outcomes. Given the serious nature of this finding, Cd is a potential adverse agent that impacts pregnancy and future neonatal health. Further comprehensive studies covering the whole trimesters of pregnancy and neonatal developments are warranted. Data on the molecular mechanisms behind Cd-induced PE is also essential for potential preventive, diagnostic, or therapeutic targets.

Melatonin prevents histopathologies stem from cadmium chloride in pregnant mice lungs

Heavy metals may cause structural and functional changes in organs. Cadmium, taken into the body through oral and respiratory routes, can lead to lesions. Cadmium may lead to lesions by accumulating in organs. The lungs are significantly affected by cadmium. Melatonin, an antioxidant hormone with therapeutic effects, is secreted by the pineal gland. The aim of the study is to treat cadmium-induced lesions in the lungs of pregnant mice with Melatonin. Four groups were created with 24 pregnant mice, named Control, Cadmium Chloride, Melatonin, and Melatonin + Cadmium Chloride groups (n: 6) Cadmium Chloride (2 mg/kg/bw) and Melatonin (3 mg/kg/bw) were given orally through gavage during pregnancy (21 days) After routine histological procedures, the lung tissues were stained with Hematoxylin-Eosin and evaluated under a light and electron microscope. ANOVA tests were applied for one-way analysis of variance, and LSD tests were applied for pairwise comparisons (p < 0.05) The average lung weight decreased in the Cadmium Chloride group (p: 0.03) The average lung weight in the Cadmium Chloride + Melatonin group was found to be close to the control group (p: 0.06) Cadmium Chloride caused thickening of the lung alveolar wall, inflammatory cell infiltration, and fibrin deposition. Because the lesions were not observed in the Melatonin group, lesions may be prevented by melatonin. Additional studies may be useful to determine the protective effect of Melatonin at different doses of Cadmium Chloride.

Roles of airway and intestinal epithelia in responding to pathogens and maintaining tissue homeostasis

Epithelial cells form a resilient barrier and orchestrate defensive and reparative mechanisms to maintain tissue stability. This review focuses on gut and airway epithelia, which are positioned where the body interfaces with the outside world. We review the many signaling pathways and mechanisms by which epithelial cells at the interface respond to invading pathogens to mount an innate immune response and initiate adaptive immunity and communicate with other cells, including resident microbiota, to heal damaged tissue and maintain homeostasis. We compare and contrast how airway and gut epithelial cells detect pathogens, release antimicrobial effectors, collaborate with macrophages, Tregs and epithelial stem cells to mount an immune response and orchestrate tissue repair. We also describe advanced research models for studying epithelial communication and behaviors during inflammation, tissue injury and disease.

E-Cigarette Exposure Alters Neuroinflammation Gene and Protein Expression in a Murine Model: Insights from Perinatally Exposed Offspring and Post-Birth Mothers

The use of E-cigarettes, often considered a safer alternative to traditional smoking, has been associated with high rates of cellular toxicity, genetic alterations, and inflammation. Neuroinflammatory impacts of cigarette smoking during pregnancy have been associated with increased risks of adverse childhood health outcomes; however, it is still relatively unknown if the same propensity is conferred on offspring by maternal vaping during gestation. Results from our previous mouse inhalation studies suggest such a connection. In this earlier study, pregnant C57BL/6 mice were exposed daily to inhaled E-cig aerosols (i.e., propylene glycol and vegetable glycerin, [PG/VG]), with or without nicotine (16 mg/mL) by whole-body inhalation throughout gestation (3 h/d; 5 d/week; total ~3-week) and continuing postnatally from post-natal day (PND) 4-21. As neuroinflammation is involved in the dysregulation of glucose homeostasis and weight gain, this study aimed to explore genes associated with these pathways in 1-mo.-old offspring (equivalent in humans to 12-18 years of age). Results in the offspring demonstrated a significant increase in glucose metabolism protein levels in both treatment groups compared to filtered air controls. Gene expression analysis in the hypothalamus of 1 mo. old offspring exposed perinatally to E-cig aerosols, with and without nicotine, revealed significantly increased gene expression changes in multiple genes associated with neuroinflammation. In a second proof-of-principal parallel study employing the same experimental design, we shifted our focus to the hippocampus of the postpartum mothers. We targeted the mRNA levels of several neurotrophic factors (NTFs) indicative of neuroinflammation. While there were suggestive changes in mRNA expression in this study, levels failed to reach statistical significance. These studies highlight the need for ongoing research on E-cig-induced alterations in neuroinflammatory pathways.

A Review of in vivo Toxicity of Quantum Dots in Animal Models

Tremendous research efforts have been devoted to nanoparticles for applications in optoelectronics and biomedicine. Over the past decade, quantum dots (QDs) have become one of the fastest growing areas of research in nanotechnology because of outstanding photophysical properties, including narrow and symmetrical emission spectrum, broad fluorescence excitation spectrum, the tenability of the emission wavelength with the particle size and composition, anti-photobleaching ability and stable fluorescence. These characteristics are suitable for optical imaging, drug delivery and other biomedical applications. Research on QDs toxicology has demonstrated QDs affect or damage the biological system to some extent, and this situation is generally caused by the metal ions and some special properties in QDs, which hinders the further application of QDs in the biomedical field. The toxicological mechanism mainly stems from the release of heavy metal ions and generation of reactive oxygen species (ROS). At the same time, the contact reaction with QDs also cause disorders in organelles and changes in gene expression profiles. In this review, we try to present an overview of the toxicity and related toxicity mechanisms of QDs in different target organs. It is believed that the evaluation of toxicity and the synthesis of environmentally friendly QDs are the primary issues to be addressed for future widespread applications. However, considering the many different types and potential modifications, this review on the potential toxicity of QDs is still not clearly elucidated, and further research is needed on this meaningful topic.

Cadmium Sulfide Quantum Dots Adversely Affect Gametogenesis in Saccharomyces cerevisiae

In the last decades, nanotechnology-based tools have attracted attention in the scientific community, due to their potential applications in different areas from medicine to engineering, but several toxicological effects mediated by these advanced materials have been shown on the environment and human health. At present, the effects of engineered nanomaterials on gametogenesis have not yet been well understood. In the present study, we addressed this issue using the yeast Saccharomyces cerevisiae as a model eukaryote to evaluate the effects of cadmium sulfide quantum dots (CdS QDs) on sporulation, a process equivalent to gametogenesis in higher organisms. We have observed that CdS QDs cause a strong inhibition of spore development with the formation of aberrant, multinucleated cells. In line with these observations, treatment with CdS QDs down-regulates genes encoding crucial regulators of sporulation process, in particular, the transcription factor Ndt80 that coordinates different genes involved in progression through the meiosis and spore morphogenesis. Down-regulation of NDT80 mediated by CdS QDs causes a block of the meiotic cell cycle and a return to mitosis, leading to the formation of aberrant, multinucleated cells. These results indicate that CdS QDs inhibit gametogenesis in an irreversible manner, with adverse effects on cell-cycle progression.

Adverse Impact of Environmental Chemicals on Developmental Origins of Kidney Disease and Hypertension

Chronic kidney disease (CKD) and hypertension are becoming a global health challenge, despite developments in pharmacotherapy. Both diseases can begin in early life by so-called "developmental origins of health and disease" (DOHaD). Environmental chemical exposure during pregnancy can affect kidney development, resulting in renal programming. Here, we focus on environmental chemicals that pregnant mothers are likely to be exposed, including dioxins, bisphenol A (BPA), phthalates, per- and polyfluoroalkyl substances (PFAS), polycyclic aromatic hydrocarbons (PAH), heavy metals, and air pollution. We summarize current human evidence and animal models that supports the link between prenatal exposure to environmental chemicals and developmental origins of kidney disease and hypertension, with an emphasis on common mechanisms. These include oxidative stress, renin-angiotensin system, reduced nephron numbers, and aryl hydrocarbon receptor signaling pathway. Urgent action is required to identify toxic chemicals in the environment, avoid harmful chemicals exposure during pregnancy and lactation, and continue to discover other potentially harmful chemicals. Innovation is also needed to identify kidney disease and hypertension in the earliest stage, as well as translating effective reprogramming interventions from animal studies into clinical practice. Toward DOHaD approach, prohibiting toxic chemical exposure and better understanding of underlying mechanisms, we have the potential to reduce global burden of kidney disease and hypertension.

Potential protective roles of curcumin against cadmium-induced toxicity and oxidative stress

Curcumin, used as a spice and traditional medicine in India, exerts beneficial effects against several diseases, owing to its antioxidant, analgesic, and anti-inflammatory properties. Evidence indicates that curcumin might protect against heavy metal-induced organ toxicity by targeting biological pathways involved in anti-oxidation, anti-inflammation, and anti-tumorigenesis. Curcumin has received considerable attention owing to its therapeutic properties, and the mechanisms underlying some of its actions have been recently investigated. Cadmium (Cd) is a heavy metal found in the environment and used extensively in industries. Chronic Cd exposure induces damage to bones, liver, kidneys, lungs, testes, and the immune and cardiovascular systems. Because of its long half-life, exposure to even low Cd levels might be harmful. Cd-induced toxicity involves the overproduction of reactive oxygen species (ROS), resulting in oxidative stress and damage to essential biomolecules. Dietary antioxidants, such as chelating agents, display the potential to reduce Cd accumulation and metal-induced toxicity. Curcumin scavenges ROS and inhibits oxidative damage, thus resulting in many therapeutic properties. This review aims to address the effectiveness of curcumin against Cd-induced organ toxicity and presents evidence supporting the use of curcumin as a protective antioxidant.

Developmental toxicity of cadmium in infants and children: a review

Several millions of people are exposed to cadmium worldwide due to natural and anthropogenic activities that led to their widespread distribution in the environment and have shown potential adverse effects on the kidneys, liver, heart and nervous system. Recently human and animal-based studies have been shown that In utero and early life exposure to cadmium can have serious health issues that are related to the risk of developmental disabilities and other outcomes in adulthood. Since, cadmium crosses the placental barrier and reaches easily to the fetus, even moderate or high-level exposure of this metal during pregnancy could be of serious health consequences which might be reflected either in the children’s early or later stages of life. Mortality from various diseases including cancer, cardiovascular, respiratory, kidney and neurological problems, correlation with In utero or early life exposure to cadmium has been found in epidemiological studies. Animal studies with strong evidence of various diseases mostly support for the human studies, as well as suggested a myriad mechanism by which cadmium can interfere with human health and development. More studies are needed to establish the mechanism of cadmium-induced toxicity with environmentally relevant doses in childhood and later life. In this review, we provide a comprehensive examination of the literature addressing potential long- term health issues with In utero and early life exposure to cadmium, as well as correlating with human and animal exposure studies.

Comprehensive Review of Cadmium Toxicity Mechanisms in Male Reproduction and Therapeutic Strategies

Cadmium (Cd) has been widely studied as an environmental pollutant for many years. Numerous studies have reported that Cd exposure causes damage to the heart, liver, kidneys, and thyroid in vivo. The emerging evidence suggests that Cd exposure induces damage on male reproductive system, which is related to oxidative stress, inflammation, steroidogenesis disruption, and epigenetics. Current preclinical animal studies have confirmed a large number of proteins and intracellular signaling pathways involved in the pathological process of Cd-induced male reproductive damage and potential measures for prophylaxis and treatment, which primarily include antioxidants, anti-inflammatory agents, and essential ion supplement. However, explicit pathogenesis and effective treatments remain uncertain. This review collects data from the literatures, discusses the underlying mechanisms of Cd-induced toxicity on male reproductive function, and summarizes evidence that may provide guidance for the treatment and prevention of Cd-induced male reproductive toxicity.

Prenatal Exposure to Gutkha, a Globally Relevant Smokeless Tobacco Product, Induces Hepatic Changes in Adult Mice

Maternal exposures during pregnancy affect the onset and progression of adult diseases in the offspring. A prior mouse study indicated that maternal tobacco smoke exposure affects hepatic fibrosis in adult offspring. Gutkha, a broadly used smokeless tobacco (ST) product, is widely used by pregnant woman in many countries. The objective of this murine study was to evaluate whether oral maternal exposure to gutkha during pregnancy alters non-alcoholic fatty liver disease (NAFLD) in adult offspring: risk factors for the progression of NAFLD to cirrhosis in adults remain elusive. Buccal cavity 'painting' of pregnant mice with gutkha began on gestational days (GD) 2-4 and continued until parturition. Beginning at 12 weeks of age, a subset of offspring were transitioned to a high-fat diet (HFD). Results demonstrated that prenatal exposure to gutkha followed by an HFD in adulthood significantly increased the histologic evidence of fatty liver disease only in adult male offspring. Changes in hepatic fibrosis-related cytokines (interleukin (IL)-1b and IL-6) and in hepatic collagen mRNA expression were observed when comparing adult male offspring exposed to gutkha in utero to those not exposed. These findings indicate that maternal use of gutkha during pregnancy affects NAFLD in adult offspring in a sex-dependent manner.

Nanostructured metal oxides and its hybrids for photocatalytic and biomedical applications

Metal oxide nanoparticles and its hybrids are deemed to be one of the most attractive materials in an extensive range of applications due to their impressive optical, electronic, photocatalytic, and biological properties. Metal oxide based nanomaterials with extraordinary characteristics have been proposed, prepared, and used as main materials in the recent area of photocatalysis and biomedicine, due to their non-toxic nature, large specific surface area, useful optical bandgap, and high biological activity. Herein, this review reveals the recent advance development in the area like photocatalytic, anticancer and antibacterial performance of metal oxide nanomaterials for multidimensional applications. Consequently, we also focused on the encountered difficulties and prospects for the future application of metal oxide-based composites as promising candidates for the development of highly efficient photocatalytic and biomedical systems. This review article also delivers advanced knowledge to the scientific community who intends to design efficient photocatalytic and biomedical systems.

Paternal cadmium exposure increases the susceptibility to diet-induced testicular injury and spermatogenic disorders in mouse offspring

The impairments of gestational cadmium (Cd) exposure on testicular development and male fertility in offspring have been reported. Here, we investigated the effect of paternal low-concentration cadmium exposure on testicular development and spermatogenesis in offspring. Five-week-old male mice were exposed to cadmium chloride (100 mg/L) in drinking water for 20 weeks. Results presented that Cd did not affect the testicular histology and sperm count in mice. After mating with untreated females, pregnant mice and pups were then evaluated. No significant difference in the rate for successful pregnancy and the body weight of pups was observed in Cd-exposed mice compared to the controls. Male offspring were given with a chow and high-fat diet from postnatal day (PND) 35 to PND70. Our data indicated that high-fat diet obviously decreased No. of sperm in epididymides of adult offspring due to paternal Cd exposure. Testicular histology revealed that the percentage of seminiferous tubules in stages IX-XII and the atypical residual bodies positive tubules in CdH (paternal cadmium exposure and pubertal high-fat diet) group were higher than these in CdC (paternal cadmium exposure and pubertal chow diet) group. Further analysis demonstrated that high-fat diet markedly accelerated testicular apoptosis, as determined by TUNEL assay and immunostaining for cleaved caspase-3, in male offspring due to paternal Cd exposure. Collectively, high-fat diet exacerbates the damage of testicular development and spermatogenesis in offspring due to paternal cadmium exposure.

Cadmium exposure during pregnancy and lactation: materno-fetal and newborn repercussions of Cd(ii), and Cd-metallothionein complexes

Cadmium (Cd) is a non-physiological heavy metal that can be harmful at low concentrations. Increasing anthropogenic activities are incrementing the risk of accumulation of this heavy metal in different organs and tissues of the body. In the case of pregnant women, the threat is more serious due to the implications affecting not only their own health but also fetal development as well. Metallothioneins (MTs), small cysteine-rich proteins, are involved in zinc (Zn) and copper homeostasis in mammals but can, however, also bind with Cd if present. The accumulation of Cd in maternal tissues (e.g. placenta, maternal blood, and mammary glands) induces the synthesis of MTs, preferably MT2, in an attempt to sequester the metal to avoid toxicity. The formed Cd-MT complexes will avoid the Cd transport from the placenta to the fetus and end up accumulating in the maternal kidneys. At the same time, high concentrations of MTs will increase the formation of Zn-MT complexes, therefore decreasing the amount of Zn ions available to be transported to the fetus by means of Zn transporters such as ZnT2, ZIP14 and DMT1. Although MTs cannot transport Cd from the mother to the fetus, the divalent DMT1 transporter is suggested to carry the metal to the fetus. As a consequence, the low levels of Zn(ii) in the fetus, together with the presence of Cd(ii) coming from the mother either via the placenta and cord blood or via breast milk induce changes in the fetal development including fetal growth retardation, and low weight or height of the newborn. Likewise, the concentrations of Cd(ii) in the newborn can cause alterations such as cognitive disabilities. In summary, the presence of Cd(ii) in the maternal tissues will induce MT synthesis in an attempt to detoxify these tissues and reduce the possible toxicity of Cd in fetal and newborn tissues.

Effect of Gestational Age on Maternofetal Vascular Function Following Single Maternal Engineered Nanoparticle Exposure

Normal pregnancy outcome is accomplished, in part, by rapid and expansive physiological adaptations to the systemic circulation, the extent of which is specific to gestational day (GD) and anatomical location. Pregnancy-related hemodynamic changes in uterine placental blood flow stimulate compensatory vascular signaling and remodeling that begins early and continues throughout gestation. Exposure of the maternal environment to engineered nanomaterials (ENM) during pregnancy has been shown to impact health of the dam, fetus, and adult offspring; however, the consequences of specific temporal (gestational age) and spatial (vascular location) considerations are largely undetermined. We exposed pregnant Sprague-Dawley rats to nano-TiO2 aerosols at three critical periods of fetal development (GD 4, 12, and 17) to identify vascular perturbations associated with ENM exposure at these developmental milestones. Vascular reactivity of the maternal thoracic aorta, the uterine artery, the umbilical vein, and the fetal thoracic aorta were evaluated using wire myography on GD 20. While impairments were noted at each level of the maternofetal vascular tree and at each exposure day, our results indicate the greatest effects may be identified within the fetal vasculature (umbilical vein and fetal aorta), wherein effects of a single maternal inhalational exposure to nano-TiO2 on GD 4 modified responses to cholinergic, NO, and α-adrenergic signaling.

Nasr S. Monitoring of Carcinogenic Environmental Pollutants in raw Cows’ Milk

These investigations were conducted to detect the residues of polycyclic aromatic hydrocarbons, lead, and cadmium in the raw milk samples of lactating cows grazing around the Sugar Cane Factory. One hundred raw milk samples were collected from apparent healthy lactating cows during the rest and work periods of the Sugar Cane Factory. Detection of polycyclic aromatic hydrocarbons residue in milk samples was performed using a gas chromatography. Lead and cadmium levels in the milk samples were determined after digestion. Results revealed that benzo(a)anthracene and indeno(1,2,3-cd)pyrene (carcinogenic), and acenaphthylene and phenanthrene non-carcinogenic were detected only in the raw milk samples during the work period, while fluoranthene and benzo(a)pyrene were detected only during the rest period. However, chrysene and benzo(b) fluoranthene (carcinogenic) were detected in the milk at the rest and work periods of the Sugar Cane Factory. The highest levels of lead and cadmium were detected during the work period compared to the levels of lead and cadmium at rest. In conclusion, benzo(a)anthracene, indeno(1,2,3-cd)pyrene, acenaphthylene, and phenanthrene, lead and cadmium could be detected in cows’ milk which raised around the Sugar Cane Factory. Further investigations of these pollutants must be done in water, plants, air, and soil around this factory.

Biological monitoring of workers exposed to engineered nanomaterials

As the number of nanomaterial workers increase there is need to consider whether biomonitoring of exposure should be used as a routine risk management tool. Currently, no biomonitoring of nanomaterials is mandated by authoritative or regulatory agencies. However, there is a growing knowledge base to support such biomonitoring, but further research is needed as are investigations of priorities for biomonitoring. That research should be focused on validation of biomarkers of exposure and effect. Some biomarkers of effect are generally nonspecific. These biomarkers need further interpretation before they should be used. Overall biomonitoring of nanomaterial workers may be important to supplement risk assessment and risk management efforts.

Engineered nanomaterial applications in perinatal therapeutics

Engineered nanomaterials (ENM) are widely used in commercial, domestic, and more recently biomedical applications. While the majority of exposures to ENM are unintentional, biomedical platforms are being evaluated for use in individualized and/or tissue-targeted therapies. Treatments are often avoided during prenatal periods to reduce adverse effects on the developing fetus. The placenta is central to maternal-fetal medicine. Perturbation of placental functions can limit transfer of necessary nutrients, alter production of hormones needed during pregnancy, or allow undesired passage of xenobiotics to the developing fetus. The development of therapeutics to target specific maternal, placental, or fetal tissues would be especially important to reduce or circumvent toxicities. Therefore, this review will discuss the potential use of ENM in perinatal medicine, the applicable physiochemical properties of ENM in therapeutic use, and current methodologies of ENM testing in perinatal medicine, and identify maternal, fetal, and offspring concerns associated with ENM exposure during gestation. As potential nanoparticle-based therapies continue to develop, so does the need for thorough consideration and evaluation for use in perinatal medicine.

Low-dose cadmium exposure exacerbates polyhexamethylene guanidine-induced lung fibrosis in mice

Cadmium (Cd) is a toxic metal present in tobacco smoke, air, food, and water. Inhalation is an important route of Cd exposure, and lungs are one of the main target organs for metal-induced toxicity. Cd inhalation is associated with an increased risk of pulmonary diseases. The present study aimed to assess the effects of repeated exposure to low-dose Cd in a mouse model of polyhexamethylene guanidine (PHMG)-induced lung fibrosis. Mice were grouped into the following groups: vehicle control (VC), PHMG, cadmium chloride (CdCl₂), and PHMG + CdCl₂. Animals in the PHMG group exhibited increased numbers of total cells and inflammatory cells in the bronchoalveolar lavage fluid (BALF) accompanied by inflammation and fibrosis in lung tissues. These parameters were exacerbated in mice in the PHMG + CdCl₂ group. In contrast, mice in the CdCl₂ group alone displayed only minimal inflammation in pulmonary tissue. Expression of inflammatory cytokines and fibrogenic mediators was significantly elevated in lungs of mice in the PHMG group compared with that VC. Further, expression of these cytokines and mediators was enhanced in pulmonary tissue in mice administered PHMG + CdCl₂. Data demonstrate that repeated exposure to low-dose Cd may enhance the development of PHMG-induced pulmonary fibrosis.

Nanomaterial exposure, toxicity, and impact on human health

The use of engineered nanomaterials (ENM) has grown after the turn of the 21st century. Also, the production of ENM has globally grown, and exposure of workers especially via the lungs to ENM has increased. This review tackles with effects of ENM on workers' health because occupational environment is the main source of exposure to ENM. Assessment of exposure to ENM is demanding, and today there are no occupational exposure level (OEL) for ENM. This is partly due to challenges of such measurements, and in part to the unknown causality between ENM metrics and effects. There are also marked gaps in systematic knowledge on ENM hazards. Human health surveys of exposed workers, or human field studies have not identified specific effects of ENM linking them with a specific exposure. There is, however, a consensus that material characteristics such as size, and chemistry influence effects of ENM. Available data suggest that multiwalled carbon nanotubes (MWCNT) affect the immunological system and cause inflammation of the lungs, or signs of asthma whereas carbon nanofibers (CNF) may cause interstitial fibrosis. Metallic and metal oxide nanoparticles together with MWCNT induce genotoxicity, and a given type of MWCNT has been identified as a possible human carcinogen. Currently, lack of understanding of mechanisms of effects of ENM renders assessment of hazards and risks of ENM material-by-material a necessity. The so called "omics" approaches utilizing ENM-induced alterations in gene and protein expression may be useful in the development of a new paradigm for ENM hazard and risk assessment. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Maternal engineered nanomaterial inhalation during gestation alters the fetal transcriptome

Background

The integration of engineered nanomaterials (ENM) is well-established and widespread in clinical, commercial, and domestic applications. Cardiovascular dysfunctions have been reported in adult populations after exposure to a variety of ENM. As the diversity of these exposures continues to increase, the fetal ramifications of maternal exposures have yet to be determined. We, and others, have explored the consequences of ENM inhalation during gestation and identified many cardiovascular and metabolic outcomes in the F1 generation. The purpose of these studies was to identify genetic alterations in the F1 generation of Sprague-Dawley rats that result from maternal ENM inhalation during gestation. Pregnant dams were exposed to nano-titanium dioxide (nano-TiO₂) aerosols (10 ± 0.5 mg/m³) for 7-8 days (calculated, cumulative lung deposition = 217 ± 1 μg) and on GD (gestational day) 20 fetal hearts were isolated. DNA was extracted and immunoprecipitated with modified chromatin marks histone 3 lysine 4 tri-methylation (H3K4me3) and histone 3 lysine 27 tri-methylation (H3K27me3). Following chromatin immunoprecipitation (ChIP), DNA fragments were sequenced. RNA from fetal hearts was purified and prepared for RNA sequencing and transcriptomic analysis. Ingenuity Pathway Analysis (IPA) was then used to identify pathways most modified by gestational ENM exposure.

Results

The results of the sequencing experiments provide initial evidence that significant epigenetic and transcriptomic changes occur in the cardiac tissue of maternal nano-TiO₂ exposed progeny. The most notable alterations in major biologic systems included immune adaptation and organismal growth. Changes in normal physiology were linked with other tissues, including liver and kidneys.

Conclusions

These results are the first evidence that maternal ENM inhalation impacts the fetal epigenome.

Electronic supplementary material

The online version of this article (10.1186/s12989-017-0239-8) contains supplementary material, which is available to authorized users.

Pretreatment with N-acetyl cysteine suppresses chronic reactive astrogliosis following maternal nanoparticle exposure during gestational period

Early pregnant employees are potentially and unintendedly exposed to industrial chemicals including nanoparticles. Developmental toxicity of nanoparticle exposure has been concerned because exposure to fine particle including carbon black nanoparticle (CB-NP) during the brain developmental stage enhances the risk of brain disorders. Maternal CB-NP exposure dose-dependently induces astrogliosis, which is an abnormal increase in the reactive astrocytes with glial fibrillary acidic protein (GFAP) and aquaporin-4 overexpression due to the destruction of nearby neurons and blood vessels. The present study aimed to investigate protective effects of antioxidants on the histopathological denaturation with astrogliosis following maternal CB-NP exposure in offspring mice, thereby to evaluate the role of oxidative stress on the developmental toxicity. Pregnant ICR mice were treated with CB-NP by intranasal instillation on gestational days 5 and 9. N-acetyl cysteine (NAC) or ascorbic acid was intraperitoneally administered to the pregnant mice 1 h prior to CB-NP instillation. The brains were collected from 6- to 12-week-old offspring mice and analyzed using western blotting and immunohistochemistry. NAC suppressed GFAP overexpression in 6- and 12-week-old offspring mice following maternal CB-NP exposure. However, NAC did not suppress aquaporin-4 overexpression following maternal CB-NP exposure. Ascorbic acid did not suppress, but rather slightly and significantly enhanced the expression of GFAP and aquaporin-4. These results indicate that astrogliosis by maternal CB-NP exposure is partially prevented by NAC pretreatment. Oxidative stress is a possible key factor of developmental neurotoxicity of maternal NP exposure. This study will contribute to elucidating the mechanisms underlying the effects of developmental neurotoxicity of NPs.

Evaluation of distribution, redox parameters, and genotoxicity in Wistar rats co-exposed to silver and titanium dioxide nanoparticles

The increasing production of silver nanoparticles (AgNPs) and titanium dioxide nanoparticles (TiO₂NPs) has resulted in their elevated concentrations in the environment. This study was, therefore, aimed at determining the distribution, redox parameters, and genotoxic effects in male Wistar rats that were treated with either AgNP or TiO₂NP individually, as well as under a co-exposure scenario. Animals were exposed via oral gavage to either sodium citrate buffer (vehicle), 0.5 mg/kg/day TiO₂NP, 0.5 mg/kg/day AgNP or a mixture of TiO₂NPs and AgNPs. Exposure lasted 45 days after which rats were sacrificed, and tissue biodistribution of Ag and Ti measured. The blood concentration of glutathione (GSH) and activities of glutathione peroxidase (GPx) and catalase (CAT) were determined while the genotoxicity was analyzed using the comet assay in peripheral blood and liver cells. The tissue concentrations of Ag followed the order; blood > liver > kidneys while for Ti the order was kidneys > liver > blood. There was no significant change in the measured redox parameters in animals that were exposed to TiO₂NPs. However, there was a significant increase in GSH levels accompanied by a reduction in the GPx activity in AgNP-treated and co-exposed groups. The individual or co-exposure to TiO₂NP and AgNP did not markedly induce genotoxicity in blood or liver cells. Data showed that TiO₂NP did not produce significant oxidative stress or genotoxicity in rats at the dose used in this study while the same dose level of AgNPs resulted in oxidative stress, but no noticeable adverse genotoxic effects.

Cadmium Handling, Toxicity and Molecular Targets Involved during Pregnancy: Lessons from Experimental Models

Even decades after the discovery of Cadmium (Cd) toxicity, research on this heavy metal is still a hot topic in scientific literature: as we wrote this review, more than 1440 scientific articles had been published and listed by the PubMed.gov website during 2017. Cadmium is one of the most common and harmful heavy metals present in our environment. Since pregnancy is a very particular physiological condition that could impact and modify essential pathways involved in the handling of Cd, the prenatal life is a critical stage for exposure to this non-essential element. To give the reader an overview of the possible mechanisms involved in the multiple organ toxic effects in fetuses after the exposure to Cd during pregnancy, we decided to compile some of the most relevant experimental studies performed in experimental models and to summarize the advances in this field such as the Cd distribution and the factors that could alter it (diet, binding-proteins and membrane transporters), the Cd-induced toxicity in dams (preeclampsia, fertility, kidney injury, alteration in essential element homeostasis and bone mineralization), in placenta and in fetus (teratogenicity, central nervous system, liver and kidney).

Nanoparticles and female reproductive system: how do nanoparticles affect oogenesis and embryonic development

Along with the increasing application of nanoparticles (NPs) in many walks of life, environmental exposure to NPs has raised considerable health concerns. When NPs enter a pregnant woman’s body through inhalation, venous injection, ingestion or skin permeation, maternal toxic stress reactions such as reactive oxygen species (ROS), inflammation, apoptosis and endocrine dyscrasia are induced in different organs, particularly in the reproductive organs. Recent studies have shown that NPs disturb the developing oocyte by invading the protective barrier of theca cells, granulosa cell layers and zona pellucida. NPs disrupt sex hormone levels through the hypothalamic–pituitary-gonadal axis or by direct stimulation of secretory cells, such as granule cells, follicle cells, thecal cells and the corpus luteum. Some NPs can cross the placenta into the fetus by passive diffusion or endocytosis, which can trigger fetal inflammation, apoptosis, genotoxicity, cytotoxicity, low weight, reproductive deficiency, nervous damage, and immunodeficiency, among others. The toxicity of these NPs depend on their size, dosage, shape, charge, material and surface-coating. We summarize new findings on the toxic effect of various NPs on the ovary and on oogenesis and embryonic development. Meanwhile, we highlight the problems that need to be studied in the future. This manuscript will also provide valuable guidelines for protecting the female reproductive system from the toxicity of NPs and provide a certain reference value for NP application in the area of ovarian diseases.

Selective detection of ZnO nanoparticles in aqueous suspension by capillary electrophoresis analysis using dithiothreitol and L-cysteine adsorbates

The UV detection sensitivity of ZnO nanoparticles in capillary electrophoresis (CE) analysis was selectively enhanced, by 27 or 19 folds, after adsorption of dithiothreitol (DTT) or cysteine (Cys) in 10mM sodium phosphate buffer. Adsorption equilibrium was reached within 90min for DTT but only 10min for Cys. The adsorption process was best modeled by the Langmuir isotherm, indicating the formation of a monolayer of DTT or Cys on the surface of ZnO nanoparticles. The selectivity of DTT and Cys towards ZnO nanoparticles was tested using alumina (Al₂O₃), ceria (CeO₂), silica (SiO₂) and titania (TiO₂) nanoparticles. No changes in the CE-UV peak area of either adsorbates or nanoparticles were observed, indicating a lack of adsorption. Dynamic light scattering (DLS) provided similar evidence of the selectivity of both adsorbates towards ZnO. Cys also improved the colloidal stability of ZnO nanoparticles by breaking down the aggregates, as evidenced by a reduction of their average hydrodynamic diameter. This new analytical approach provides a simple and rapid methodology to detect ZnO nanoparticles selectively by CE-UV analysis with enhanced sensitivity.

Effect of surfactant in mitigating cadmium oxide nanoparticle toxicity: Implications for mitigating cadmium toxicity in environment

Cadmium (Cd), classified as human carcinogen, is an extremely toxic heavy metal pollutant, and there is an increasing environmental concern for cadmium exposure through anthropogenic sources including cigarette smoke. Though Cd based nanoparticles such as cadmium oxide (CdO) are being widely used in a variety of clinical and industrial applications, the toxicity of CdO nanoparticles has not been well characterized. Herein we report the toxicity of CdO nanoparticles employing zebrafish as a model. Two different CdO nanoparticles were prepared, calcination of Cd(OH)₂ without any organic molecule (CdO-1) and calcination of Cd-citrate coordination polymer (CdO-2), to evaluate and compare the toxicity of these two different CdO nanoparticles. Results show that zebrafish exposed to CdO-2 nanoparticles expressed reduced toxicity as judged by lower oxidative stress levels, rescue of liver carboxylesterases and reduction in metallothionein activity compared to CdO-1 nanoparticles. Histopathological observations also support our contention that CdO-1 nanoparticles showed higher toxicity relative to CdO-2 nanoparticles. The organic unit of Cd-citrate coordination polymer might have converted into carbon during calcination that might have covered the surface of CdO nanoparticles. This carbon surface coverage can control the release of Cd²⁺ ions in CdO-2 compared to non-covered CdO-1 nanoparticles and hence mitigate the toxicity in the case of CdO-2. This was supported by atomic absorption spectrophotometer analyses of Cd²⁺ ions release from CdO-1 and CdO-2 nanoparticles. Thus the present study clearly demonstrates the toxicity of CdO nanoparticles in an aquatic animal and also indicates that the toxicity could be substantially reduced by carbon coverage. This could have important implications in terms of anthropogenic release and environmental pollution caused by Cd and human exposure to Cd²⁺ from sources such as cigarette smoke.

Risk assessment of zinc oxide, a cosmetic ingredient used as a UV filter of sunscreens

Zinc oxide (ZnO), an inorganic compound that appears as a white powder, is used frequently as an ingredient in sunscreens. The aim of this review was to examine the toxicology and risk assessment of ZnO based upon available published data. Recent studies on acute, sub-acute, and chronic toxicities of ZnO indicated that this compound is virtually non-toxic in animal models. However, it was reported that ZnO nanoparticles (NP) (particle size, 40 nm) induced significant changes in anemia-related hematologic parameters and mild to moderate pancreatitis in male and female Sprague-Dawley rats at 536.8 mg/kg/day in a 13-week oral toxicity study. ZnO displayed no carcinogenic potential, and skin penetration is low. No-observed-adverse-effect level (NOAEL) ZnO was determined to be 268.4 mg/kg/day in a 13-week oral toxicity study, and a maximum systemic exposure dose (SED) of ZnO was estimated to be 0.6 mg/kg/day based on topical application of sunscreen containing ZnO. Subsequently, the lowest margin of safety (MOS) was estimated to be 448.2, which indicates that the use of ZnO in sunscreen is safe. A risk assessment was undertaken considering other routes of exposure (inhalation or oral) and major product types (cream, lotion, spray, and propellant). Human data revealed that MOS values (7.37 for skin exposure from cream and lotion type; 8.64 for skin exposure of spray type; 12.87 for inhalation exposure of propellant type; 3.32 for oral exposure of sunscreen) are all within the safe range (MOS > 1). Risk assessment of ZnO indicates that this compound may be used safely in cosmetic products within the current regulatory limits of 25% in Korea.

Inhaled Cadmium Oxide Nanoparticles: Their in Vivo Fate and Effect on Target Organs

The increasing amount of heavy metals used in manufacturing equivalently increases hazards of environmental pollution by industrial products such as cadmium oxide (CdO) nanoparticles. Here, we aimed to unravel the CdO nanoparticle destiny upon their entry into lungs by inhalations, with the main focus on the ultrastructural changes that the nanoparticles may cause to tissues of the primary and secondary target organs. We indeed found the CdO nanoparticles to be transported from the lungs into secondary target organs by blood. In lungs, inhaled CdO nanoparticles caused significant alterations in parenchyma tissue including hyperemia, enlarged pulmonary septa, congested capillaries, alveolar emphysema and small areas of atelectasis. Nanoparticles were observed in the cytoplasm of cells lining bronchioles, in the alveolar spaces as well as inside the membranous pneumocytes and in phagosomes of lung macrophages. Nanoparticles even penetrated through the membrane into some organelles including mitochondria and they also accumulated in the cytoplasmic vesicles. In livers, inhalation caused periportal inflammation and local hepatic necrosis. Only minor changes such as diffusely thickened filtration membrane with intramembranous electron dense deposits were observed in kidney. Taken together, inhaled CdO nanoparticles not only accumulated in lungs but they were also transported to other organs causing serious damage at tissue as well as cellular level.

Impacts of prenatal nanomaterial exposure on male adult Sprague-Dawley rat behavior and cognition

It is generally accepted that gestational xenobiotic exposures result in systemic consequences in the adult F1 generation. However, data on detailed behavioral and cognitive consequences remain limited. Using our whole-body nanoparticle inhalation facility, pregnant Sprague-Dawley rats (gestational day [GD] 7) were exposed 4 d/wk to either filtered air (control) or nano-titanium dioxide aerosols (nano-TiO2; count median aerodynamic diameter of 170.9 ± 6.4 nm, 10.4 ± 0.4 mg/m(3), 5 h/d) for 7.8 ± 0.5 d of the remaining gestational period. All rats received their final exposure on GD 20 prior to delivery. The calculated daily maternal deposition was 13.9 ± 0.5 µg. Subsequently, at 5 mo of age, behavior and cognitive functions of these pups were evaluated employing a standard battery of locomotion, learning, and anxiety tests. These assessments revealed significant working impairments, especially under maximal mnemonic challenge, and possible deficits in initial motivation in male F1 adults. Evidence indicates that maternal engineered nanomaterial exposure during gestation produces psychological deficits that persist into adulthood in male rats.