Maternal inhalation of carbon black nanoparticles induces neurodevelopmental changes in mouse offspring

Nervous system exposure of different classes of nanoparticles: A review on potential toxicity and mechanistic studies

Nanoparticles (NPs) are generally defined as very small particles in the size range of 1-100 nm. Due to the rapid development of modern society, many new materials have been developed. The widespread use of NPs in medical applications, the food industry and the textile industry has led to an increase in NPs in the environment and the possibility of human contact, which poses a serious threat to human health. The nervous system plays a leading role in maintaining the integrity and unity of the body and maintaining a harmonious balance with the external environment. Therefore, based on two categories of organic and inorganic NPs, this paper systematically summarizes the toxic effects and mechanisms of NPs released into the nervous system. The results showed that exposure to NPs may damage the nervous system, decrease learning and cognitive ability, and affect embryonic development. Finally, a remediation scheme for NPs entering the body via the environment is also introduced. This scheme aims to reduce the neurotoxicity caused by NPs by supplementing NPs with a combination of antioxidant and anti-inflammatory compounds. The results provide a valuable reference for future research in this field.

Unravelling the toxicity of carbon nanomaterials - From cellular interactions to mechanistic understanding

The application of carbon nanomaterials in diverse fields has substantially increased their demand for commercial usage. Within the earliest decade, the development of functional materials has further increased the significance of this element. Despite the advancements recorded, the potential harmful impacts of embracing carbon nanomaterials for biological applications must be balanced against their advantages. Interestingly, many studies have neglected the intriguing and dynamic cellular interaction of carbon nanomaterials and the mechanistic understanding of their property-driven behaviour, even though common toxicity profiles have been reported. Reiterating the toxicity issue, several researchers conclude that these materials have minimal toxicity and may be safe for contact with biological systems at certain dosages. Here, we aim to provide a report on the significance of some of the properties that influence their toxicity. After that, a description of the implication of nanotoxicology in humans and living systems, revealing piece by piece their exposure routes and possible risks, will be provided. Then, an extensive discussion of the mechanistic puzzle modulating the interface between various human cellular systems and carbon nanomaterials such as carbon nanotubes, carbon dots, graphene, fullerenes, and nanodiamonds will follow. Finally, this review also sheds light on the organization that handles the risk associated with nanomaterials.

Associations of air pollution exposures in preconception and pregnancy with birth outcomes and infant neurocognitive development: analysis of the Complex Lipids in Mothers and Babies (CLIMB) prospective cohort in Chongqing, China

OBJECTIVES

To investigate the associations of traffic-related air pollution exposures in early pregnancy with birth outcomes and infant neurocognitive development.

DESIGN

Cohort study.

SETTING

Eligible women attended six visits in the maternity clinics of two centres, the First Affiliated Hospital of Chongqing Medical University and Chongqing Health Centre for Women and Children.

PARTICIPANTS

Women who were between 20 and 40 years of age and were at 11-14 weeks gestation with a singleton pregnancy were eligible for participation. Women were excluded if they had a history of premature delivery before 32 weeks of gestation, maternal milk allergy or aversion or severe lactose intolerance. 1273 pregnant women enrolled in 2015-2016 and 1174 live births were included in this analysis.

EXPOSURES

Air pollution concentrations at their home addresses, including particulate matter with diameter ≤2.5 µm (PM2.5) and nitrogen dioxide (NO2), during pre-conception and each trimester period were estimated using land-use regression models.

OUTCOME MEASURES

Birth outcomes (ie, birth weight, birth length, preterm birth, low birth weight, large for gestational age and small for gestational age (SGA) status) and neurodevelopment outcomes measured by the Chinese version of Bayley Scales of Infant Development.

RESULTS

An association between SGA and per-IQR increases in NO2 was found in the first trimester (OR: 1.57, 95% CI: 1.06 to 2.32) and during the whole pregnancy (OR: 1.33, 99% CI: 1.01 to 1.75). Both PM2.5 and NO2 exposure in the 90 days prior to conception were associated with lower Psychomotor Development Index scores (β: -6.15, 95% CI: -8.84 to -3.46; β: -2.83, 95% CI: -4.27 to -1.39, respectively). Increased NO2 exposure was associated with an increased risk of psychomotor development delay during different trimesters of pregnancy.

CONCLUSIONS

Increased exposures to NO2 during pregnancy were associated with increased risks of SGA and psychomotor development delay, while increased exposures to both PM2.5 and NO2 pre-conception were associated with adverse psychomotor development outcomes at 12 months of age.

TRIAL REGISTRATION NUMBER

ChiCTR-IOR-16007700.

Gestational Exposure to PM2.5 and Specific Constituents, Meconium Metabolites, and Neonatal Neurobehavioral Development: A Cohort Study

Exposure to fine particulate matter (PM2.5) during pregnancy has been inversely associated with neonatal neurological development. However, the associations of exposure to specific PM2.5 constituents with neonatal neurological development remain unclear. We investigated these associations and examined the mediating role of meconium metabolites in a Chinese birth cohort consisting of 294 mother-infant pairs. Our results revealed that exposure to PM2.5 and its specific constituents (i.e., organic matter, black carbon, sulfate, nitrate, and ammonium) in the second trimester, but not in the first or third trimester, was inversely associated with the total neonatal behavioral neurological assessment (NBNA) scores. The PM2.5 constituent mixture in the second trimester was also inversely associated with NBNA scores, and sulfate was identified as the largest contributor. Furthermore, meconium metabolome analysis identified four metabolites, namely, threonine, lysine, leucine, and saccharopine, that were associated with both PM2.5 constituents and NBNA scores. Threonine was identified as an important mediator, accounting for a considerable proportion (14.53-15.33%) of the observed inverse associations. Our findings suggest that maternal exposure to PM2.5 and specific constituents may adversely affect neonatal behavioral development, in which meconium metabolites may play a mediating role.

Lysosomal dysfunction in carbon black-induced lung disorders

Carbon black (CB), a component of environmental particulate pollution derived from carbon sources, poses a significant threat to human health, particularly in the context of lung-related disease. This study aimed to investigate the detrimental effects of aggregated CB in the average micron scale on lung tissues and cells in vitro and in vivo. We observed that CB particles induced lung disorders characterized by enhanced expression of inflammation, necrosis, and fibrosis-related factors in vivo. In alveolar epithelial cells, CB exposure resulted in decreased cell viability, induction of cell death, and generation of reactive oxidative species, along with altered expression of proteins associated with lung disorders. Our findings suggested that the damaging effects of CB on the lung involved the targeting of lysosomes. Specifically, CB promoted lysosomal membrane permeabilization, while lysosomal alkalization mitigated the harmfulness of CB on lung cells. Additionally, we explored the protective effects of alkaloids derived from Nelumbinis plumula, with a focus on neferine, against CB-induced lung disorders. In conclusion, these findings contribute to a deeper understanding of the pathophysiological effects of CB particles on the lungs and propose a potential therapeutic approach for pollution-related diseases.

Prenatal ambient air pollutant mixture exposure and neurodevelopment in urban children in the Northeastern United States

BACKGROUND

Studies of prenatal air pollution (AP) exposure on child neurodevelopment have mostly focused on a single pollutant. We leveraged daily exposure data and implemented novel data-driven statistical approaches to assess effects of prenatal exposure to a mixture of seven air pollutants on cognitive functioning in school-age children from an urban pregnancy cohort.

METHODS

Analyses included 236 children born at ≥37 weeks gestation. Maternal prenatal daily exposure levels for nitrogen dioxide (NO2), ozone (O3), and constituents of fine particles [elemental carbon (EC), organic carbon (OC), nitrate (NO3-), sulfate (SO42-), ammonium (NH4+)] were estimated based on residential addresses using validated satellite-based hybrid models or global 3-D chemical-transport models. Children completed Wide Range Assessment of Memory and Learning (WRAML-2) and Conners' Continuous Performance Test (CPT-II) at 6.5 ± 0.9 years of age. Time-weighted levels for mixture pollutants were estimated using Bayesian Kernel Machine Regression Distributed Lag Models (BKMR-DLMs), with which we also explored the interactions in the exposure-response functions among pollutants. Resulting time-weighted exposure levels were used in Weighted Quantile Sum (WQS) regressions to examine AP mixture effects on outcomes, adjusted for maternal age, education, child sex, and prenatal temperature.

RESULTS

Mothers were primarily ethnic minorities (81% Hispanic and/or black) reporting ≤12 years of education (68%). Prenatal AP mixture (per unit increase in WQS estimated AP index) was associated with decreased WRAML-2 general memory (GM; β = -0.64, 95%CI = -1.40, 0.00) and memory-related attention/concentration (AC; β = -1.03, 95%CI = -1.78, -0.27) indices, indicating poorer memory functioning, as well as increased CPT-II omission errors (OE; β = 1.55, 95%CI = 0.34, 2.77), indicating increased attention problems. When stratified by sex, association with AC index was significant among girls, while association with OE was significant among boys. Traffic-related pollutants (NO2, OC, EC) and SO42- were major contributors to these associations. There was no significant evidence of interactions among mixture components.

CONCLUSIONS

Prenatal exposure to an AP mixture was associated with child neurocognitive outcomes in a sex- and domain-specific manner.

Neurodevelopmental toxicity induced by airborne particulate matter

Airborne particulate matter (PM), the primary component associated with health risks in air pollution, can negatively impact human health. Studies have shown that PM can enter the brain by inhalation, but data on the exact quantity of particles that reach the brain are unknown. Particulate matter exposure can result in neurotoxicity. Exposure to PM poses a greater health risk to infants and children because their nervous systems are not fully developed. This review paper highlights the association between PM and neurodevelopmental toxicity (NDT). Exposure to PM can induce oxidative stress and inflammation, potentially resulting in blood-brain barrier damage and increased susceptibility to development of neurodevelopmental disorders (NDD), such as autism spectrum disorders and attention deficit disorders. In addition, human and animal exposure to PM can induce microglia activation and epigenetic alterations and alter the neurotransmitter levels, which may increase risks for development of NDD. However, the systematic comparisons of the effects of PM on NDD at different ages of exposure are deficient. The elucidation of PM exposure risks and NDT in children during the early developmental stages are of great importance. The synthesis of current research may help to identify markers and mechanisms of PM-induced neurodevelopmental toxicity, allowing for the development of strategies to prevent permanent damage of developing brain.

Effects of prenatal exposure to PM2.5 and its composition on cognitive and motor functions in children at 12 months of age: The Shanghai Birth Cohort Study

BACKGROUND

Prenatal fine particulate matter (PM_2.5) exposure has been linked to infant cognitive and motor functions, but the effects of PM_2.5 chemical composition remain unclear.

OBJECTIVES

We aimed to explore the associations of prenatal PM_2.5 and its composition exposure with infant cognitive and motor functions.

METHODS

We studied 2,435 mother-infant pairs in the Shanghai Birth Cohort Study. PM_2.5 and its seven compositions [primary particles (black carbon, mineral dust and sea salts) and secondary particles (NH₄⁺, NO₃^-, SO₄^2- and organic matter)] during thethreetrimesters ofpregnancy were retrieved from the V4.CH.03 product developed by using a combined geoscience-statistical method. At the 12-month-old follow-up, infant cognitive and motor functions in five domains were assessed using the Ages and Stages Questionnaire (ASQ). We used multivariable linear regressions to estimate the effects of PM_2.5 and its composition on the ASQ scores, for all infants and stratifying by sex and breastfeeding duration.

RESULTS

PM_2.5 exposure was negatively associated with gross motor, problem-solving and personal-social scores for all infants. PM_2.5 compositions were inversely associated with ASQ scores in all five domains, and the effects of different compositions varied across domains. Specifically, all compositions except organic matter were correlated with lower problem-solving scores [e.g., ( [Formula: see text]  =  - 10.79, 95 % CI: -17.40, -4.18) ∼ ( [Formula: see text]  =  - 4.68, 95 % CI: -7.84, -1.53); for each 10 μg/m³ increase in PM_2.5 compositions during the third trimester]. Primary and some secondary particles (organic matter, NO₃^-) were related to lower gross motor scores. Secondary particles were also inversely associated with communication (organic matter and NO₃^-), fine motor (NH₄⁺, NO₃^-, SO₄^2-) and personal-social (NH₄⁺) scores. Additionally, boys and infants breastfed for < 6 months appeared to be more susceptible.

CONCLUSIONS

We found negative associations of PM_2.5 and its compositions with infant cognitive and motor functions over a range of domains, especially the problem-solving domain.

Air pollution, depressive and anxiety disorders, and brain effects: A systematic review

Accumulating data suggest that air pollution increases the risk of internalizing psychopathology, including anxiety and depressive disorders. Moreover, the link between air pollution and poor mental health may relate to neurostructural and neurofunctional changes. We systematically reviewed the MEDLINE database in September 2021 for original articles reporting effects of air pollution on 1) internalizing symptoms and behaviors (anxiety or depression) and 2) frontolimbic brain regions (i.e., hippocampus, amygdala, prefrontal cortex). One hundred and eleven articles on mental health (76% human, 24% animals) and 92 on brain structure and function (11% human, 86% animals) were identified. For literature search 1, the most common pollutants examined were PM2.5 (64.9%), NO2 (37.8%), and PM10 (33.3%). For literature search 2, the most common pollutants examined were PM2.5 (32.6%), O3 (26.1%) and Diesel Exhaust Particles (DEP) (26.1%). The majority of studies (73%) reported higher internalizing symptoms and behaviors with higher air pollution exposure. Air pollution was consistently associated (95% of articles reported significant findings) with neurostructural and neurofunctional effects (e.g., increased inflammation and oxidative stress, changes to neurotransmitters and neuromodulators and their metabolites) within multiple brain regions (24% of articles), or within the hippocampus (66%), PFC (7%), and amygdala (1%). For both literature searches, the most studied exposure time frames were adulthood (48% and 59% for literature searches 1 and 2, respectively) and the prenatal period (26% and 27% for literature searches 1 and 2, respectively). Forty-three percent and 29% of studies assessed more than one exposure window in literature search 1 and 2, respectively. The extant literature suggests that air pollution is associated with increased depressive and anxiety symptoms and behaviors, and alterations in brain regions implicated in risk of psychopathology. However, there are several gaps in the literature, including: limited studies examining the neural consequences of air pollution in humans. Further, a comprehensive developmental approach is needed to examine windows of susceptibility to exposure and track the emergence of psychopathology following air pollution exposure.

Carbonaceous Nanoparticle Air Pollution: Toxicity and Detection in Biological Samples

Among the different air pollutants, particulate matter (PM) is of great concern due to its abundant presence in the atmosphere, which results in adverse effects on the environment and human health. The different components of PM can be classified based on their physicochemical properties. Carbonaceous particles (CPs) constitute a major fraction of ultrafine PM and have the most harmful effects. Herein, we present a detailed overview of the main components of CPs, e.g., carbon black (CB), black carbon (BC), and brown carbon (BrC), from natural and anthropogenic sources. The emission sources and the adverse effects of CPs on the environment and human health are discussed. Particularly, we provide a detailed overview of the reported toxic effects of CPs in the human body, such as respiratory effects, cardiovascular effects, neurodegenerative effects, carcinogenic effects, etc. In addition, we also discuss the challenges faced by and limitations of the available analytical techniques for the qualitative and quantitative detection of CPs in atmospheric and biological samples. Considering the heterogeneous nature of CPs and biological samples, a detailed overview of different analytical techniques for the detection of CPs in (real-exposure) biological samples is also provided. This review provides useful insights into the classification, toxicity, and detection of CPs in biological samples.

Titanium dioxide and carbon black nanoparticles disrupt neuronal homeostasis via excessive activation of cellular prion protein signaling

Background

Epidemiological emerging evidence shows that human exposure to some nanosized materials present in the environment would contribute to the onset and/or progression of Alzheimer’s disease (AD). The cellular and molecular mechanisms whereby nanoparticles would exert some adverse effects towards neurons and take part in AD pathology are nevertheless unknown.

Results

Here, we provide the prime evidence that titanium dioxide (TiO₂) and carbon black (CB) nanoparticles (NPs) bind the cellular form of the prion protein (PrP^C), a plasma membrane protein well known for its implication in prion diseases and prion-like diseases, such as AD. The interaction between TiO₂- or CB-NPs and PrP^C at the surface of neuronal cells grown in culture corrupts PrP^C signaling function. This triggers PrP^C-dependent activation of NADPH oxidase and subsequent production of reactive oxygen species (ROS) that alters redox equilibrium. Through PrP^C interaction, NPs also promote the activation of 3-phosphoinositide-dependent kinase 1 (PDK1), which in turn provokes the internalization of the neuroprotective TACE α-secretase. This diverts TACE cleavage activity away from (i) TNFα receptors (TNFR), whose accumulation at the plasma membrane augments the vulnerability of NP-exposed neuronal cells to TNFα -associated inflammation, and (ii) the amyloid precursor protein APP, leading to overproduction of neurotoxic amyloid Aβ40/42 peptides. The silencing of PrP^C or the pharmacological inhibition of PDK1 protects neuronal cells from TiO₂- and CB-NPs effects regarding ROS production, TNFα hypersensitivity, and Aβ rise. Finally, we show that dysregulation of the PrP^C-PDK1-TACE pathway likely occurs in the brain of mice injected with TiO₂-NPs by the intra-cerebro-ventricular route as we monitor a rise of TNFR at the cell surface of several groups of neurons located in distinct brain areas.

Conclusion

Our in vitro and in vivo study thus posits for the first time normal cellular prion protein PrP^C as being a neuronal receptor of TiO₂- and CB-NPs and identifies PrP^C-coupled signaling pathways by which those nanoparticles alter redox equilibrium, augment the intrinsic sensitivity of neurons to neuroinflammation, and provoke a rise of Aβ peptides. By identifying signaling cascades dysregulated by TiO₂- and CB-NPs in neurons, our data shed light on how human exposure to some NPs might be related to AD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00490-x.

S-ketamine administration in pregnant mice induces ADHD- and depression-like behaviors in offspring mice

BACKGROUND

Anesthesia and psychotropic drugs in pregnant women may cause long-term effects on the brain development of unborn babies. The authors set out to investigate the neurotoxicity of S-ketamine, which possesses anesthetic and antidepressant effects and may cause attention deficit hyperactivity disorder (ADHD)- and depression-like behaviors in offspring mice.

METHODS

Pregnant mice were administered with low-, medium-, and high-dose S-ketamine (15, 30, and 60 mg/kg) by intraperitoneal injection for 5 days from gestational day 14-18. At 21 days after birth, an elevated plus-maze test, fear conditioning, open field test, and forced swimming test were used to assess ADHD- and depression-like behaviors. Neuronal amount, glial activation, synaptic function indicated by ki67, and inhibitory presynaptic proteins revealed by GAD2 in the hippocampus, amygdala, habenula nucleus, and lateral hypothalamus (LHA) were determined by immunofluorescence assay.

RESULTS

All the pregnant mice exposed to high-dose S-ketamine administration had miscarriage after the first injection. Both low-dose and medium-dose S-ketamine administration significantly increased the open-arm time and attenuated frozen time in the fear conditioning, which indicates impulsivity and memory dysfunction-like behaviors. Medium-dose S-ketamine administration reduced locomotor activity in the open field and increased immobility time in the forced swimming test, indicating depression-like behaviors. Changes in astrocytic activation, synaptic dysfunction, and decreased inhibitory presynaptic proteins were found in the hippocampus, amygdala, and habenula nucleus.

CONCLUSIONS

These results demonstrate that S-ketamine may lead to detrimental effects, including ADHD-and depression-like behaviors in offspring mice. More studies should be promoted to determine the neurotoxicity of S-ketamine in the developing brain.

Indirect mediators of systemic health outcomes following nanoparticle inhalation exposure

The growing field of nanoscience has shed light on the wide diversity of natural and anthropogenic sources of nano-scale particulates, raising concern as to their impacts on human health. Inhalation is the most robust route of entry, with nanoparticles (NPs) evading mucociliary clearance and depositing deep into the alveolar region. Yet, impacts from inhaled NPs are evident far outside the lung, particularly on the cardiovascular system and highly vascularized organs like the brain. Peripheral effects are partly explained by the translocation of some NPs from the lung into the circulation; however, other NPs largely confined to the lung are still accompanied by systemic outcomes. Omic research has only just begun to inform on the complex myriad of molecules released from the lung to the blood as byproducts of pulmonary pathology. These indirect mediators are diverse in their molecular make-up and activity in the periphery. The present review examines systemic outcomes attributed to pulmonary NP exposure and what is known about indirect pathological mediators released from the lung into the circulation. Further focus was directed to outcomes in the brain, a highly vascularized region susceptible to acute and longer-term outcomes. Findings here support the need for big-data toxicological studies to understand what drives these health outcomes and better predict, circumvent, and treat the potential health impacts arising from NP exposure scenarios.

Exposure to atmospheric Ag, TiO2, Ti and SiO2 engineered nanoparticles modulates gut inflammatory response and microbiota in mice

The development of nanotechnologies is leading to greater abundance of engineered nanoparticles (EN) in the environment, including in the atmospheric air. To date, it has been shown that the most prevalent EN found in the air are silver (Ag), titanium dioxide (TiO₂), titanium (Ti), and silicon dioxide (SiO₂). As the intestinal tract is increasingly recognized as a target for adverse effects induced by inhalation of air particles, the aim of this study was to assess the impact of these 4 atmospheric EN on intestinal inflammation and microbiota. We assessed the combined toxicity effects of Ag, Ti, TiO₂, and SiO₂ following a 28-day inhalation protocol in male and female mice. In distal and proximal colon, and in jejunum, EN mixture inhalation did not induce overt histological damage, but led to a significant modulation of inflammatory cytokine transcript abundance, including downregulation of Tnfα, Ifnγ, Il1β, Il17a, Il22, IL10, and Cxcl1 mRNA levels in male jejunum. A dysbiosis was observed in cecal microbiota of male and female mice exposed to the EN mixture, characterized by sex-dependent modulations of specific bacterial taxa, as well as sex-independent decreased abundance of the Eggerthellaceae family. Under dextran sodium sulfate-induced inflammatory conditions, exposure to the EN mixture increased the development of colitis in both male and female mice. Moreover, the direct dose-response effects of individual and mixed EN on gut organoids was studied and Ag, TiO₂, Ti, SiO₂, and EN mixture were found to generate specific inflammatory responses in the intestinal epithelium. These results indicate that the 4 most prevalent atmospheric EN could have the ability to disturb intestinal homeostasis through direct modulation of cytokine expression in gut epithelium, and by altering the inflammatory response and microbiota composition following inhalation.

Prenatal exposure to air pollution and neurodevelopmental delay in children: A birth cohort study in Foshan, China

BACKGROUND

Prenatal exposure to air pollution may have adverse effects on neurodevelopment in children, but epidemiological evidence remains inconclusive.

OBJECTIVE

To investigate the associations between prenatal air pollution exposure and neurodevelopmental delay.

METHODS

We conducted a birth cohort study based on pregnancy and birth registry in Foshan, China. Exposure to particulate matter of aerodynamic diameter < 1 μm, 2.5 μm, 10 μm (PM₁, PM_2.5, PM₁₀), nitrogen dioxide (NO₂) and sulfur dioxide (SO₂) over pregnancy (trimester 1, 2, 3 and entire pregnancy) was estimated at each woman's residential address using spatial-temporal models. Neurodevelopmental assessment was performed by pediatricians using a five-domain scale and developmental quotient (DQ) was calculated as a global measure. Logistic regression models were used to investigate the associations between prenatal air pollution exposure and neurodevelopmental delay (DQ < 75) with adjustment for potential confounders.

RESULTS

We included 15,778 child-mother pairs in this analysis, including 1013 children with neurodevelopmental delay. We observed positive associations between prenatal exposure to air pollution and higher risk of neurodevelopmental delay in children. The adjusted odds ratios (ORs) per 10 μg/m³ elevation in PM₁, PM_2.5, PM₁₀, NO₂ and SO₂ in entire pregnancy were 1.12 [95% confidence interval (CI): 1.01, 1.25], 1.15 (95% CI: 1.03, 1.29), 1.12 (95% CI: 1.02, 1.24), 1.06 (95% CI: 0.94, 1.19) and 1.58 (95% CI: 1.11, 2.23), respectively. The associations were more robust for trimester 1 and trimester 2, especially trimester 1.

CONCLUSIONS

Exposure to air pollution during pregnancy, especially early-to-mid pregnancy, was associated with increased risk of neurodevelopmental delay in young children, indicating its adverse neurodevelopmental effects in early-life stage.

A Novel Staining Method for Detection of Brain Perivascular Injuries Induced by Nanoparticle: Periodic Acid-Schiff and Immunohistochemical Double-Staining

Background: To protect developing brain from any unfavorable effects, it is necessary to construct experimental techniques that can sensitively detect and evaluate developmental toxicity. We have previously shown that brain perivascular tissues, especially perivascular macrophages (PVMs), respond sensitively even to weak stimuli by foreign toxicants such as low-dose exposure to nanoparticle. This paper shows the protocol of a novel staining method that enables easy detection and rapid evaluation of brain perivascular abnormalities.

Methods: As weak stimulus, low-dose of carbon black nanoparticle (95 μg/kg) or titanium dioxide nanoparticle (100 μg/kg) was intranasally administered to pregnant mice at gestational days 5 and 9. The offspring brains were used to confirm the properties of PVMs and to find suitable protocols for the detection and evaluation of the mild denaturation of PVMs. Furthermore, various procedures of novel combinational double staining including periodic acid-Schiff (PAS) staining and immunohistochemistry were examined. In addition, we checked the alterations in neurotransmitter levels and the behaviors of the offspring.

Results and discussion: Maternal exposure to low-dose of nanoparticle at levels where no significant effects on the brain were observed, such as abnormal behavior, alteration of neurotransmitter levels, or microglial activation, resulted in mild denaturation of the PVMs, which was captured by PAS staining. However, it was difficult to detect and determine slight histopathological alterations. Therefore, we established PAS-immunohistochemical double-staining method for the brain. This double staining method enabled easy detection and rapid evaluation of brain perivascular abnormalities and the relationship between PVMs and the surrounding cells. In addition, this double staining allows evaluation of the histopathological denaturation of the PVMs and the associated abnormalities in the surrounding tissues in the same section.

Conclusion: The slight responses of brain perivascular tissues, such as mild denaturation of PVMs, were sensitively and easily determined by the PAS-immunohistochemical double-staining method. This double staining method is a powerful tool to assess brain perivascular injuries including PVM denaturation and the relationship between the expression of various molecules and the morphology of PVMs. We propose that the observation of the tissue around brain blood vessels using the double staining provides potential endpoints to evaluate developmental neurotoxicity.

Carbon Black Nanoparticles Selectively Alter Follicle-Stimulating Hormone Expression in vitro and in vivo in Female Mice

Toxic effects of nanoparticles on female reproductive health have been documented but the underlying mechanisms still need to be clarified. Here, we investigated the effect of carbon black nanoparticles (CB NPs) on the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), which are key regulators of gonadal gametogenesis and steroidogenesis. To that purpose, we subjected adult female mice to a weekly non-surgical intratracheal administration of CB NPs at an occupationally relevant dose over 4 weeks. We also analyzed the effects of CB NPs in vitro, using both primary cultures of pituitary cells and the LβT2 gonadotrope cell line. We report here that exposure to CB NPs does not disrupt estrous cyclicity but increases both circulating FSH levels and pituitary FSH β-subunit gene (Fshb) expression in female mice without altering circulating LH levels. Similarly, treatment of anterior pituitary or gonadotrope LβT2 cells with increasing concentrations of CB NPs dose-dependently up-regulates FSH but not LH gene expression or release. Moreover, CB NPs enhance the stimulatory effect of GnRH on Fshb expression in LβT2 cells without interfering with LH regulation. We provide evidence that CB NPs are internalized by LβT2 cells and rapidly activate the cAMP/PKA pathway. We further show that pharmacological inhibition of PKA significantly attenuates the stimulatory effect of CB NPs on Fshb expression. Altogether, our study demonstrates that exposure to CB NPs alters FSH but not LH expression and may thus lead to gonadotropin imbalance.

Respiratory exposure to carbon black nanoparticles may induce testicular structure damage and lead to decreased sperm quality in mice

Environmental carbon black nanoparticles (CBNPs) can enter into various organs including testes through the respiratory tract. However, there are few studies describing reproductive toxicity of CBNPs after respiratory exposure. In this study, male KM mice were exposed to CBNPs in their natural breathing state. Four-, 8-, and 12-week-old mice were exposed to 0, 9, 18 and 27 mg/m³ of CBNPs for 4 weeks in order to examine the relationship between CBNP exposure and age. Eight-week-old mice were exposed to CBNPs at the same four concentrations for 1-4 weeks in order to examine the effects of CBNP exposure time. After CBNP exposure, testicular oxidative stress and inflammation increased significantly, and these effects varied with exposure time. Seminiferous tubule diameter (STD), seminiferous epithelium height (SEH), the number of spermatogenic and Leydig cells, sperm motility, and sperm speed decreased significantly, and these effects varied with exposure dose. Data analyses suggested that increased oxidative stress and inflammation in testes damaged testicular morphology, spermatogenesis, and testosterone secretion, and decreased sperm quality. Morphological damage to the testes was also closely related to decreased the sperm quantity. These findings are of significance for evaluating the reproductive toxicity of CBNPs.

Prenatal exposure to ambient fine particulate matter and early childhood neurodevelopment: A population-based birth cohort study

Although previous studies have reported the adverse effect of air pollution exposure during pregnancy on neurodevelopment in children, epidemiological evidence is limited, and the results are inconsistent. This study aimed to explore the association between prenatal ambient fine particulate matter (PM_2.5) exposure and early childhood neurodevelopment in a large birth cohort study of 4009 maternal-child pairs. Prenatal daily PM_2.5 exposure concentrations at 1 km spatial revolution were estimated using high-performance machine-learning models. Neurodevelopmental outcomes of children at ages 2, 6, 12, and 24 months were assessed using the Ages and Stages Questionnaire (ASQ). Distributed lag nonlinear models were used to identify critical windows of prenatal PM_2.5 exposure. General linear mixed models with binomially distributed errors were used to estimate the effect of prenatal PM_2.5 exposure on suspected developmental delay (SDD) in five developmental domains based on the longitudinal design. Prenatal PM_2.5 exposure was significantly associated with decreased scores for all neurodevelopmental domains of children at ages 2, 6, and 24 months. Each 10-μg/m³ increase in PM_2.5 exposure was significantly associated with increased risk of SDD for all subjects (RR: 1.52 95% CI: 1.19, 2.03), specifically, in problem-solving domain for girls (RR: 2.23, 95% CI: 1.22, 4.35). Prenatal PM_2.5 exposure in weeks 18 to 34 was significantly associated with both ASQ scores and SDDs. Our study proposed that prenatal PM_2.5 exposure affected early childhood neurodevelopment evaluated with the ASQ scale. PM_2.5 exposure might increase the risk of SDD for boys and girls, specifically in the problem-solving domain for girls.

Organoids: A new approach in toxicity testing of nanotherapeutics

Nanotechnology has revolutionized diverse fields, which include agriculture, the consumer market, medicine, and other fields. Widespread use of nanotechnology-based products has led to increased prevalence of these novel formulations in the environment, which has raised concerns regarding their deleterious effects. The application of nanotechnology-based formulations into clinical use is hampered by the lack of the availability of effective in vitro systems, which could accurately assess their in vivo toxic effects. A plethora of studies has shown the hazardous effects of nanoparticle-based formulations in two-dimensional in vitro cell cultures and animal models. These have some associated disadvantages when used for the evaluation of nano-toxicity. Organoid technology fills the space between existing two-dimensional cell line culture and in vivo models. The uniqueness of organoids over other systems for evaluating toxicity caused by nano-drug formulation includes them being a co-culture of diverse cell types, dynamic flow within them that simulates the actual flow of nanoparticles within biological systems, extensive cell-cell, cell-matrix interactions, and a tissue-like morphology. Thus, it mimics the actual tissue microenvironment and, subsequently, provides an opportunity to study drug metabolism and toxico-dynamics of nanotechnology-based novel formulations. The use of organoids in the evaluation of nano-drug toxicity is in its infancy. A limited number of studies conducted so far have shown good predictive value and efficiently significant data correlation with the clinical trials. In this review, we attempt to introduce organoids of the liver, lungs, brain, kidney intestine, and potential applications to evaluate toxicity caused by nanoparticles.

The impact of (ab)normal maternal environment on cortical development

The cortex in the mammalian brain is the most complex brain region that integrates sensory information and coordinates motor and cognitive processes. To perform such functions, the cortex contains multiple subtypes of neurons that are generated during embryogenesis. Newly born neurons migrate to their proper location in the cortex, grow axons and dendrites, and form neuronal circuits. These developmental processes in the fetal brain are regulated to a large extent by a great variety of factors derived from the mother - starting from simple nutrients as building blocks and ending with hormones. Thus, when the normal maternal environment is disturbed due to maternal infection, stress, malnutrition, or toxic substances, it might have a profound impact on cortical development and the offspring can develop a variety of neurodevelopmental disorders. Here we first describe the major developmental processes which generate neuronal diversity in the cortex. We then review our knowledge of how most common maternal insults affect cortical development, perturb neuronal circuits, and lead to neurodevelopmental disorders. We further present a concept of selective vulnerability of cortical neuronal subtypes to maternal-derived insults, where the vulnerability of cortical neurons and their progenitors to an insult depends on the time (developmental period), place (location in the developing brain), and type (unique features of a cell type and an insult). Finally, we provide evidence for the existence of selective vulnerability during cortical development and identify the most vulnerable neuronal types, stages of differentiation, and developmental time for major maternal-derived insults.

A new perspective on calmodulin-regulated calcium and ROS homeostasis upon carbon black nanoparticle exposure

Toxicological studies propose that exposure to carbon black nanoparticles induces organ injuries and inflammatory responses. Besides, current understanding of the molecular mechanisms implies that carbon black nanoparticles (CBNP) exposure induces the production of reactive oxygen species (ROS) causing inflammation, mitochondrial dysfunction or disturbance in calcium homeostasis. However, the precise mechanisms whereby CBNP exert these effects in the lung are still not fully understood. To gain insight into the possible mechanism of CBNP exerted toxicity, human alveolar epithelial cells (A549) were exposed to different concentrations of CBNP and for different timepoints. The reaction of the cells was monitored by the systematic use of cell-based measurements of calcium and ROS, in the presence and absence of calcium (Ca²⁺) pump inhibitors/chelators and antioxidants. Followed by an in-depth PCR analysis of 84 oxidative stress-related genes. The measurements revealed, as compared to the control, that exposure to CBNP nanoparticles leads to the generation of high ROS levels, as well as a disturbance in calcium homeostasis, which remained primarily unchanged even after 24 h of exposure. Nevertheless, in presence of antioxidants N-acetylcysteine (NAC) and Trolox, ROS formation was considerably reduced without affecting the intracellular calcium concentration. On the other hand, Ca²⁺ pump inhibitors/chelators, BAPTA (1,2-bis(o-amino phenoxy)ethane-N, N, N′, N′-tetraacetic acid) and verapamil not only decreased the Ca²⁺ overload, but also further decreased the ROS formation, indicating its role in CBNP-induced oxidative stress. Further, a PCR array analysis of A549 cells in presence and absence of the calmodulin (CaM) antagonist W7, indicated toward nine altered oxidative stress-related genes which further confirmed our cytotoxicity results. Obtained data suggested that CBNP exposure elevates calcium ion concentration, which further contributes to oxidative stress, via the calcium-binding protein CaM. Its inhibition with W7 leads to downregulation in gene expression of nine oxidative stress-related genes, which otherwise, as compared to control, show increased gene expression. The results of the study thus confirm that exposure of lung epithelial cells to CBNP leads to oxidative stress; however, the oxidative stress itself is a result of a disturbance in both calcium and ROS homeostasis, and should be considered while searching for a new strategy for prevention of CBNP-induced lung toxicity.

Fetotoxicity of Nanoparticles: Causes and Mechanisms

The application of nanoparticles in consumer products and nanomedicines has increased dramatically in the last decade. Concerns for the nano-safety of susceptible populations are growing. Due to the small size, nanoparticles have the potential to cross the placental barrier and cause toxicity in the fetus. This review aims to identify factors associated with nanoparticle-induced fetotoxicity and the mechanisms involved, providing a better understanding of nanotoxicity at the maternal–fetal interface. The contribution of the physicochemical properties of nanoparticles (NPs), maternal physiological, and pathological conditions to the fetotoxicity is highlighted. The underlying molecular mechanisms, including oxidative stress, DNA damage, apoptosis, and autophagy are summarized. Finally, perspectives and challenges related to nanoparticle-induced fetotoxicity are also discussed.

Astrocyte responses to nanomaterials: Functional changes, pathological changes and potential applications

Astrocytes are responsible for regulating and optimizing the functional environment of neurons in the brain and can reduce the adverse impacts of external factors by protecting neurons. However, excessive astrocyte activation upon stimulation may alter their initial protective effect and actually lead to aggravation of injury. Similar to the dual effects of astrocytes in the response to injury within the central nervous system (CNS), nanomaterials (NMs) can have either toxic or beneficial effects on astrocytes, serving to promote injury or inhibit tumors. As the important physiological functions of astrocytes have been gradually revealed, the effects of NMs on astrocytes and the underlying mechanisms have become a new frontier in nanomedicine and neuroscience. This review summarizes the in vitro and in vivo findings regarding the effects of various NMs on astrocytes, focusing on functional alterations and pathological processes in astrocytes, as well as the possible underlying mechanisms. We also emphasize the importance of co-culture models in studying the interaction between NMs and cells of the CNS. Finally, we discuss NMs that have shown promise for application in astrocyte-related diseases and propose some challenges and suggestions for further investigations, with the aim of providing guidance for the widespread application of NMs in the CNS.

A European nano-registry as a reliable database for quantitative risk assessment of nanomaterials? A comparison of national approaches

Despite the fact that nanomaterials have been in use for decades and chemicals legislation is largely harmonised within the EU, quantitative and safety-relevant information on nanomaterials is still scarce. In particular, information about production volumes, their unique physicochemical properties (size, specific surface area, etc.) and nanomaterial exposure, which may lead to adverse effects on human health and the environment, is still lacking. While the latest amendments of the REACH Annexes have led to certain improvements, a harmonised EU-wide nano-registry would provide additional quantitative data for risk assessment but is not foreseeable for the near future. Since the European Commission, the European Parliament and some member states take contrasting approaches to the regulation of nanomaterials, France, Belgium, Denmark, Sweden and Norway (as a country of the European Economic Area), launched national mandatory reporting systems to collect quantitative information, thus fostering early risk assessment of nanomaterials. In this study, we compare national registries - based on a literature review and expert interviews - and show differences between the regulations under the respective national laws and REACH regulation. These include, for instance, thresholds for notification and level of detail on the specification of the nanomaterial, mixture and/or product, the definition of exceptions for the requirement to register and the timing of registration. As this heterogenous regulatory framework hinders comparability and potentially creates trade barriers, we argue that a harmonised EU-wide nano-registry would substantially improve the current situation by promoting the safe and sustainable handling of nanomaterials, increasing transparency and trust, and consequently nurturing innovation. Such an EU-wide nano-registry should both cover nanomaterials as substances or mixtures, such as in REACH registration, and the semi-/finished products they will be used in, since the exposure, and thus the hazardous potential of released nanomaterials during their life cycle, depends largely on the scope of application.

Effects of air pollution particles (ultrafine and fine particulate matter) on mitochondrial function and oxidative stress - Implications for cardiovascular and neurodegenerative diseases

Environmental pollution is a major cause of global mortality and burden of disease. All chemical pollution forms together may be responsible for up to 12 million annual excess deaths as estimated by the Lancet Commission on pollution and health as well as the World Health Organization. Ambient air pollution by particulate matter (PM) and ozone was found to be associated with an all-cause mortality rate of up to 9 million in the year 2015, with the majority being of cerebro- and cardiovascular nature (e.g. stroke and ischemic heart disease). Recent evidence suggests that exposure to airborne particles and gases contributes to and accelerates neurodegenerative diseases. Especially, airborne toxic particles contribute to these adverse health effects. Whereas it is well established that air pollution in the form of PM may lead to dysregulation of neurohormonal stress pathways and may trigger inflammation as well as oxidative stress, leading to secondary damage of cardiovascular structures, the mechanistic impact of PM-induced mitochondrial damage and dysfunction is not well established. With the present review we will discuss similarities between mitochondrial damage and dysfunction observed in the development and progression of cardiovascular disease and neurodegeneration as well as those adverse mitochondrial pathomechanisms induced by airborne PM.

Nanopolystyrene translocation and fetal deposition after acute lung exposure during late-stage pregnancy

BACKGROUND

Plastic is everywhere. It is used in food packaging, storage containers, electronics, furniture, clothing, and common single-use disposable items. Microplastic and nanoplastic particulates are formed from bulk fragmentation and disintegration of plastic pollution. Plastic particulates have recently been detected in indoor air and remote atmospheric fallout. Due to their small size, microplastic and nanoplastic particulate in the atmosphere can be inhaled and may pose a risk for human health, specifically in susceptible populations. When inhaled, nanosized particles have been shown to translocate across pulmonary cell barriers to secondary organs, including the placenta. However, the potential for maternal-to-fetal translocation of nanosized-plastic particles and the impact of nanoplastic deposition or accumulation on fetal health remain unknown. In this study we investigated whether nanopolystyrene particles can cross the placental barrier and deposit in fetal tissues after maternal pulmonary exposure.

RESULTS

Pregnant Sprague Dawley rats were exposed to 20 nm rhodamine-labeled nanopolystyrene beads (2.64 × 10¹⁴ particles) via intratracheal instillation on gestational day (GD) 19. Twenty-four hours later on GD 20, maternal and fetal tissues were evaluated using fluorescent optical imaging. Fetal tissues were fixed for particle visualization with hyperspectral microscopy. Using isolated placental perfusion, a known concentration of nanopolystyrene was injected into the uterine artery. Maternal and fetal effluents were collected for 180 min and assessed for polystyrene particle concentration. Twenty-four hours after maternal exposure, fetal and placental weights were significantly lower (7 and 8%, respectively) compared with controls. Nanopolystyrene particles were detected in the maternal lung, heart, and spleen. Polystyrene nanoparticles were also observed in the placenta, fetal liver, lungs, heart, kidney, and brain suggesting maternal lung-to-fetal tissue nanoparticle translocation in late stage pregnancy.

CONCLUSION

These studies confirm that maternal pulmonary exposure to nanopolystyrene results in the translocation of plastic particles to placental and fetal tissues and renders the fetoplacental unit vulnerable to adverse effects. These data are vital to the understanding of plastic particulate toxicology and the developmental origins of health and disease.

Propofol Exposure Disturbs the Differentiation of Rodent Neural Stem Cells via an miR-124-3p/Sp1/Cdkn1b Axis

Accumulating studies have indicated that propofol may lead to neurotoxicity and its effect on neural stem cells (NSCs) may play pivotal role in propofol-related neurotoxicity. Previously, we found that propofol could promote NSCs proliferation and could regulate several microRNA expressions. However, the underlying mechanism between microRNAs and NSCs development after propofol exposure is still unclear. Our data first observed that rat primary neural stem cells exposed to propofol exhibited a cell cycle arrest status and an inclination to differentiate into GFAP⁺ or S100β⁺ cells. This phenomenon was accompanying with a lower miR-124-3p expression and could be reversed via overexpression miR-124-3p in NSCs. Using bioinformatic predictions and luciferase assay we confirmed that Sp1 (Specificity Protein 1) is the target gene of miR-124-3p, indicating that miR-124-3p may regulate NSCs development through Sp1. Further, knockdown of Sp1 rescue the effect of propofol on NSCs differentiation. Finally, we demonstrated that Sp1 could bind cdkn1b promoter region through chromatin immunoprecipitation assay, indicating that Sp1 affect NSC's cell cycle through cdkn1b directly. Overall, our study highlights the miR-124-3p/Sp1/cdkn1b axis to be important in propofol interfering the differentiation of NSCs.

Carbon nanoparticles induce endoplasmic reticulum stress around blood vessels with accumulation of misfolded proteins in the developing brain of offspring

Nano-particulate air pollution threatens developing brains and is epidemiologically related to neurodegenerative diseases involving deposition of misfolded proteins. However, the mechanism underlying developmental neurotoxicity by nanoparticles remains unknown. Here, we report that maternal exposure to low doses of carbon black nanoparticle (CB-NP) induces endoplasmic reticulum (ER) stress associated with accumulation of misfolded proteins. Notably, offspring specifically showed high induction of ER stress in perivascular macrophages and reactive astrocytes only around brain blood vessels, along with accumulation of β-sheet-rich proteins regarded as misfolded proteins. Our results suggest that maternal CB-NP exposure induced ER stress in PVMs and reactive astrocytes around blood vessels in the brain of offspring in mice. The induction of ER stress accompanied by the perivascular accumulation of misfolded proteins is likely to be associated with perivascular abnormalities and neurodegeneration, and development of neurodegenerative diseases related to particulate air pollution.

Concentrated ambient fine particulate matter (PM2.5) exposure induce brain damage in pre and postnatal exposed mice

Air pollution is a public health concern that has been associated with adverse effects on the development and functions of the central nervous system (CNS). However, studies on the effects of exposure to pollutants on the CNS across the entire developmental period still remain scarce. In this study, we investigated the impacts of prenatal and/or postnatal exposure to fine particulate matter (PM_2.5) from São Paulo city, on the brain structure and behavior of juvenile male mice. BALB/c mice were exposed to PM_2.5 concentrated ambient particles (CAP) at a daily concentration of 600 μg/m³ during the gestational [gestational day (GD) 1.5-18.5] and the postnatal periods [postnatal day (PND) 22-90] to filtered air (FA) in both periods (FA/FA), to CAP only in the postnatal period (FA/CAP), to CAP only in the gestational period (CAP/FA), and to CAP in both periods (CAP/CAP). Behavioral tests were performed when animals were at PND 30 and PND 90. Glial activation, brain volume, cortical neuron number, serotonergic and GABAergic receptors, as well as oxidative stress, were measured. Mice at PND 90 presented greater behavioral changes in the form of greater locomotor activity in the FA-CAP and CAP-CAP groups. In general, these same groups explored objects longer and the CAP-FA group presented anxiolytic behavior. There was no difference in total brain volume among groups, but a lower corpus callosum (CC) volume was observed in the CAP-FA group. Also, the CAP-CAP group presented an increase in microglia in the cortex and an increased in astrocytes in the cortex, CC, and C1A and dentate gyrus of hippocampus regions. Gene expression analysis showed a decrease in BDNF in the hippocampus of CAP-CAP group. Treatment of immortalized glial cells with non-cytotoxic doses of ambient PM_2.5 increased micronuclei frequencies, indicating genomic instability. These findings highlight the potential for negative neurodevelopmental outcomes induced by exposure to moderate levels of PM_2.5 in Sao Paulo city.

Neurotoxicology of Nanomaterials

The remarkable advances coming about through nanotechnology promise to revolutionize many aspects of modern life; however, these advances come with a responsibility for due diligence to ensure that they are not accompanied by adverse consequences for human health or the environment. Many novel nanomaterials (having at least one dimension <100 nm) could be highly mobile if released into the environment and are also very reactive, which has raised concerns for potential adverse impacts including, among others, the potential for neurotoxicity. Several lines of evidence led to concerns for neurotoxicity, but perhaps none more than observations that inhaled nanoparticles impinging on the mucosal surface of the nasal epithelium could be internalized into olfactory receptor neurons and transported by axoplasmic transport into the olfactory bulbs without crossing the blood-brain barrier. From the olfactory bulb, there is concern that nanomaterials may be transported deeper into the brain and affect other brain structures. Of course, people will not be exposed to only engineered nanomaterials, but rather such exposures will occur in a complex mixture of environmental materials, some of which are incidentally generated particles of a similar inhalable size range to engineered nanomaterials. To date, most experimental studies of potential neurotoxicity of nanomaterials have not considered the potential exposure sources and pathways that could lead to exposure, and most studies of nanomaterial exposure have not considered potential neurotoxicity. Here, we present a review of potential sources of exposures to nanoparticles, along with a review of the literature on potential neurotoxicity of nanomaterials. We employ the linked concepts of an aggregate exposure pathway (AEP) and an adverse outcome pathway (AOP) to organize and present the material. The AEP includes a sequence of key events progressing from material sources, release to environmental media, external exposure, internal exposure, and distribution to the target site. The AOP begins with toxicant at the target site causing a molecular initiating event and, like the AEP, progress sequentially to actions at the level of the cell, organ, individual, and population. Reports of nanomaterial actions are described at every key event along the AEP and AOP, except for changes in exposed populations that have not yet been observed. At this last stage, however, there is ample evidence of population level effects from exposure to ambient air particles that may act similarly to engineered nanomaterials. The data give an overall impression that current exposure levels may be considerably lower than those reported experimentally to be neurotoxic. This impression, however, is tempered by the absence of long-term exposure studies with realistic routes and levels of exposure to address concerns for chronic accumulation of materials or damage. Further, missing across the board are "key event relationships", which are quantitative expressions linking the key events of either the AEP or the AOP, making it impossible to quantitatively project the likelihood of adverse neurotoxic effects from exposure to nanomaterials or to estimate margins of exposure for such relationships.

Neurotoxicity of e-cigarettes

It appears that electronic cigarettes (EC) are a less harmful alternative to conventional cigarette (CC) smoking, as they generate substantially lower levels of harmful carcinogens and other toxic compounds. Thus, switching from CC to EC may be beneficial for smokers. However, recent accounts of EC- or vaping-associated lung injury (EVALI) has raised concerns regarding their adverse health effects. Additionally, the increasing popularity of EC among vulnerable populations, such as adolescents and pregnant women, calls for further EC safety evaluation. In this state-of-the-art review, we provide an update on recent findings regarding the neurological effects induced by EC exposure. Moreover, we discuss possible neurotoxic effects of nicotine and numerous other chemicals which are inherent both to e-liquids and EC aerosols. We conclude that in recognizing pertinent issues associated with EC usage, both government and scientific researchers must address this public health issue with utmost urgency.

Exposure to carbon black nanoparticles increases seizure susceptibility in male mice

Carbon black nanoparticles (CBNPs) can enter the central nervous system through blood circulation and olfactory nerves, affecting brain development or increasing neurological disease susceptibility. However, whether CBNPs exposure affects seizure is unclear. Herein, mice were exposed to two different doses of CBNPs (21 and 103 μg/animal) based on previous studies and the maximum exposure limitation (4 mg/m³) in occupational workplaces set by the Chinese government. In the pentylenetetrazol (PTZ) and kainic acid (KA) seizure models, high-dose CBNPs exposure increased seizure susceptibility in both models and increased spontaneous recurrent seizure (SRS) frequency in the KA model. In vivo local field potential (LFP) recording in KA model mice revealed that both low-dose and high-dose CBNPs exposure increased seizure-like event (SLE) frequency in the SRS interval but shortened SLE duration. Intriguingly, H&E staining and Nissl staining on brain tissue revealed that CBNPs exposure did not cause significant brain tissue morphology or neuronal damage. Detection of inflammatory factors, such as TNF-α, TGF-β1, IL-1β, and IL-6, in brain tissue showed that only high dose of CBNPs exposure increased the expression of cortical TGF-β1. By using the primary cultured neurons, we observed that CBNPs exposure not only significantly decreased the expression of the neuronal marker MAP2 but also enhanced the levels of action potential frequency in the neurons. In general, CBNPs exposure can affect abnormal epileptic discharges during the seizure interval and enhance susceptibility to frequent seizures. Our findings suggest that minimizing CBNPs exposure may be a potential way to prevent or ease seizure.

Chitosan coating does not prevent the effect of the transfer of green silver nanoparticles biosynthesized by Streptomyces malachitus into fetuses via the placenta

Green synthesized nanoparticles are more advantageous over conventionally prepared ones due to less toxicity, production cost, and environmental hazards. With the widespread of the utilization of nanoparticles, little is known about the maternal-fetal transplacental transfer of green nanoparticles. We have biosynthesized silver nanoparticles using metabolites of Streptomyces malachitus and sunlight then coated them with chitosan. These nanoparticles have been characterized and intraperitoneally administered at doses of 100 mg/kg on the 6^th, 8^th, and 10^th gestational days. On the 18^th day of pregnancy, both coated and non-coted NPs were detected in different maternal tissues, placenta, and in fetuses, as determined by estimation of silver content and observation by electron microscopy. Chitosan coating decreased the silver content in different tissues, maybe due to the larger size of coated nanoparticles that retards the transfer. The toxic effects on maternal and fetal tissues were proportional to their silver content, as determined by the liver and kidney functional analysis of pregnant rats and the ultrastructural and histopathological examination of the maternal liver, placenta and fetal liver. The present data suggest that green silver nanoparticles biosynthesized by Streptomyces malachitus cross the placenta and have toxic effects on maternal tissues, placenta, and fetus. Chitosan coating of these nanoparticles decreases the transfer, and consequently, the toxicity. However, it does not prevent this toxicity.

Short review: Air pollution, noise and lack of greenness as risk factors for Alzheimer's disease- epidemiologic and experimental evidence

The number of patients with Alzheimer's disease (AD) is likely to triple in a few decades as the world's population ages. Given the high personal and societal burden of this disease, it is imperative to identify its risk factors. The etiology of AD is still not fully understood, but environmental factors have emerged as plausible important risk factors on the population-level. In this short review, the author summarizes literature on air pollution, noise and (lack of) greenness as risk factors for AD. In conclusion, a link between air pollution and AD is supported by experimental studies as well as epidemiological studies, although a multi-exposure approach is lacking in most epidemiological studies. Although evidence is much more limited regarding noise and (lack of) greenness as risk factors for AD, future epidemiological studies should have a multi-exposure approach in order to separate potential effects of air pollution, noise and lack of greenness. Given the heavy toll of AD on individuals and society, as well as the ubiquitous nature of environmental factors, a link between environmental stressors and AD deserves special attention.

The role of sex in particle-induced inflammation and injury

The use of engineered nanomaterials within various applications such as medicine, electronics, and cosmetics has been steadily increasing; therefore, the rate of occupational and environmental exposures has also increased. Inhalation is an important route of exposure to nanomaterials and has been shown to cause various respiratory diseases in animal models. Human lung disease frequently presents with a sex/gender-bias in prevalence or severity, but investigation of potential sex-differences in the adverse health outcomes associated with nanoparticle inhalation is greatly lacking. Only ~20% of basic research in the general sciences use both male and female animals and a substantial percentage of these do not address differences between sexes within their analyses. This has prevented researchers from fully understanding the impact of sex-based variables on health and disease, particularly the pathologies resulting from the inhalation of particles. The mechanisms responsible for sex-differences in respiratory disease remain unclear, but could be related to a number of variables including sex-differences in hormone signaling, lung physiology, or respiratory immune function. By incorporating sex-based analysis into respiratory nanotoxicology and utilizing human data from other relevant particles (e.g., asbestos, silica, particulate matter), we can improve our understanding of sex as a biological variable in nanoparticle exposures. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials.

Characterization of serum metabolites as biomarkers of carbon black nanoparticles-induced subchronic toxicity in rats by hybrid triple quadrupole time-of-flight mass spectrometry with non-targeted metabolomics strategy

Carbon black nanoparticles (CBNPs) are one of atmospheric particles components and have been closely related with a series of lung diseases. It can reach the depths of the respiratory tract or even alveolar more easily than those micro-particles. Although some of its toxicities have been confirmed in animals or human bodies, the subchronic toxicity mechanism of CBNPs has been uncertain so far. Therefore, it is very necessary to establish a novel method and clarify the mechanism of subchronic toxicity caused by concentration adjustments of small molecule metabolites in vivo. In animal experiments, CB exposure, recovery and control group were set up. The concentration of CBNPs in chamber was 30.06 ± 4.42 mg/m³. We developed a UHPLC-Q-TOF-MS/MS-based non-targeted metabolomic analysis strategy to analyze serum samples of rats. Then, differential metabolites in serum were found by multivariate data analysis and 39 potential biomarkers were identified. It was showed that main metabolic pathways associated with CBNPs exposure were hormones metabolism, amino acid metabolism, nucleotide metabolism and lipid metabolism. It is worth noting that long-term exposure to CBNPs had the greatest impact on steroid hormones biosynthesis so that the risk of infertility could increase. The results provided a new mechanistic insight into the metabolic alterations owing to CBNPs induced subchronic toxicity.

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

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

Identification and quantification of gold engineered nanomaterials and impaired fluid transfer across the rat placenta via ex vivo perfusion

Development and implementation of products incorporating nanoparticles are occurring at a rapid pace. These particles are widely utilized in domestic, occupational, and biomedical applications. Currently, it is unclear if pregnant women will be able to take advantage of the potential biomedical nanoproducts out of concerns associated with placental transfer and fetal interactions. We recently developed an ex vivo rat placental perfusion technique to allow for the evaluation of xenobiotic transfer and placental physiological perturbations. In this study, a segment of the uterine horn and associated placenta was isolated from pregnant (gestational day 20) Sprague-Dawley rats and placed into a modified pressure myography vessel chamber. The proximal and distal ends of the maternal uterine artery and the vessels of the umbilical cord were cannulated, secured, and perfused with physiological salt solution (PSS). The proximal uterine artery and umbilical artery were pressurized at 80 mmHg and 50 mmHg, respectively, to allow countercurrent flow through the placenta. After equilibration, a single 900 μL bolus dose of 20 nm gold engineered nanoparticles (Au-ENM) was introduced into the proximal maternal artery. Distal uterine and umbilical vein effluents were collected every 10 min for 180 min to measure placental fluid dynamics. The quantification of Au-ENM transfer was conducted via inductively coupled plasma mass spectrometry (ICP-MS). Overall, we were able to measure Au-ENM within uterine and umbilical effluent with 20 min of material infusion. This novel methodology may be widely incorporated into studies of pharmacology, toxicology, and placental physiology.

Suitability of 3D human brain spheroid models to distinguish toxic effects of gold and poly-lactic acid nanoparticles to assess biocompatibility for brain drug delivery

Background

The blood brain barrier (BBB) is the bottleneck of brain-targeted drug development. Due to their physico-chemical properties, nanoparticles (NP) can cross the BBB and accumulate in different areas of the central nervous system (CNS), thus are potential tools to carry drugs and treat brain disorders. In vitro systems and animal models have demonstrated that some NP types promote neurotoxic effects such as neuroinflammation and neurodegeneration in the CNS. Thus, risk assessment of the NP is required, but current 2D cell cultures fail to mimic complex in vivo cellular interactions, while animal models do not necessarily reflect human effects due to physiological and species differences.

Results

We evaluated the suitability of in vitro models that mimic the human CNS physiology, studying the effects of metallic gold NP (AuNP) functionalized with sodium citrate (Au-SC), or polyethylene glycol (Au-PEG), and polymeric polylactic acid NP (PLA-NP). Two different 3D neural models were used (i) human dopaminergic neurons differentiated from the LUHMES cell line (3D LUHMES) and (ii) human iPSC-derived brain spheroids (BrainSpheres). We evaluated NP uptake, mitochondrial membrane potential, viability, morphology, secretion of cytokines, chemokines and growth factors, and expression of genes related to ROS regulation after 24 and 72 h exposures. NP were efficiently taken up by spheroids, especially when PEGylated and in presence of glia. AuNP, especially PEGylated AuNP, effected mitochondria and anti-oxidative defense. PLA-NP were slightly cytotoxic to 3D LUHMES with no effects to BrainSpheres.

Conclusions

3D brain models, both monocellular and multicellular are useful in studying NP neurotoxicity and can help identify how specific cell types of CNS are affected by NP.

Electronic supplementary material

The online version of this article (10.1186/s12989-019-0307-3) contains supplementary material, which is available to authorized users.

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

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

Particle toxicology and health - where are we?

BACKGROUND

Particles and fibres affect human health as a function of their properties such as chemical composition, size and shape but also depending on complex interactions in an organism that occur at various levels between particle uptake and target organ responses. While particulate pollution is one of the leading contributors to the global burden of disease, particles are also increasingly used for medical purposes. Over the past decades we have gained considerable experience in how particle properties and particle-bio interactions are linked to human health. This insight is useful for improved risk management in the case of unwanted health effects but also for developing novel medical therapies. The concepts that help us better understand particles' and fibres' risks include the fate of particles in the body; exposure, dosimetry and dose-metrics and the 5 Bs: bioavailability, biopersistence, bioprocessing, biomodification and bioclearance of (nano)particles. This includes the role of the biomolecule corona, immunity and systemic responses, non-specific effects in the lungs and other body parts, particle effects and the developing body, and the link from the natural environment to human health. The importance of these different concepts for the human health risk depends not only on the properties of the particles and fibres, but is also strongly influenced by production, use and disposal scenarios.

CONCLUSIONS

Lessons learned from the past can prove helpful for the future of the field, notably for understanding novel particles and fibres and for defining appropriate risk management and governance approaches.

Exposure to carbon black nanoparticles during pregnancy persistently damages the cerebrovascular function in female mice

Maternal exposure to carbon black nanoparticles (CBNPs) during pregnancy have been well documented to induce harmful outcomes of offspring on brain function. However, it remains largely unknown whether females exposed to CBNPs during sensitive period of pregnancy can cause the neurotoxic effects on their own body after parturition. In this study, our results showed that pregnancy CBNPs exposure induced the persistent pathological changes in the cerebral cortex tissues and impaired cerebrovascular function of mice manifested by significant alterations of endothelin-1, endothelial nitric oxide synthase, vascular endothelial growth factor-A and ATP-binding cassette transporter G1. Intriguingly, we observed that these deleterious effects on brain and cerebrovascular functions in mice could persist for 49 days after delivery of pups. By using in vitro human umbilical vein endothelial cells, we further verified the potential vascular dysfunction after CBNPs exposure. In summary, our results provide the first evidence that pregnancy CBNPs exposure-induced brain pathological changes and cerebrovascular dysfunction can persist for a relative long time. These finding suggest exposure to CBNPs during sensitive stages of pregnancy may not only show the harmful effects on offspring neurodevelopment, but also result in the irreversible brain damage on mother body.

Effects of maternal inhalation of carbon black nanoparticles on reproductive and fertility parameters in a four-generation study of male mice

Background

Previous findings indicate that in utero exposure to nanoparticles may affect the reproductive system in male offspring. Effects such as decreased sperm counts and testicular structural changes in F1 males have been reported following maternal airway exposure to carbon black during gestation. In addition, a previous study in our laboratory suggested that the effects of in utero exposure of nanoparticles may span further than the first generation, as sperm content per gram of testis was significantly lowered in F2 males. In the present study we assessed male fertility parameters following in utero inhalation exposure to carbon black in four generations of mice.

Results

Filter measurements demonstrated that the time-mated females were exposed to a mean total suspended particle mass concentration of 4.79 ± 1.86 or 33.87 ± 14.77 mg/m³ for the low and high exposure, respectively. The control exposure was below the detection limit (LOD 0.08 mg/m³). Exposure did not affect gestation and litter parameters in any generation. No significant changes were observed in body and reproductive organ weights, epididymal sperm parameters, daily sperm production, plasma testosterone or fertility.

Conclusion

In utero exposure to carbon black nanoparticles, at occupationally relevant exposure levels, via maternal whole body inhalation did not affect male-specific reproductive, fertility and litter parameters in four generations of mice.