Nanoparticles can cross mouse placenta and induce trophoblast apoptosis

Exposure of the human placental primary cells to nanoplastics induces cytotoxic effects, an inflammatory response and endocrine disruption

Humans are inevitably exposed to micro- and nanoplastics (MP/NP). These particles are able to cross the biological barriers and enter the bloodstream with levels close to 1.6 µg mL-1; MP/NP have been detected in placentas and meconium of newborns. However, the consequences of this exposure on the integrity, development and functions of the human placenta are not documented. In this study, trophoblasts purified from human placentas at term were exposed for 48 h, to two different sizes of polystyrene nanoparticles (PS-NP) of 20 nm (PS-NP20) and 100 nm (PS-NP100), at environmental and supra-environmental concentrations (0.01-100 µg mL-1). Cell viability, oxidative stress, mitochondrial dynamics, lysosomal degradation processes, autophagy, inflammation/oxidative responses and consequences for placental endocrine and angiogenic functions were assessed. PS-NP size determines their internalization rate and their behavior in trophoblasts. Indeed, PS-NP20 are more rapidly translocated, and accumulated in lysosomes as shown by confocal and TEM imaging. They induce higher cytotoxicity than PS-NP100, as early as 1 µg mL-1 (p < 0.05). In addition, they induce a pro-inflammatory cytokines response: IL-1ß is induced from 0.01 µg mL-1 for the both nanoparticle sizes; IL-6, and TNF-α are overexpressed at 100 µg mL-1 only for PS-NP20 (p < 0.05). For the first time, we report that PS-NP disrupt endocrine function, as observed by a decreased hCG release at concentrations found in human blood. This work, provides an in-depth in vitro assessment of the effects of PS-NP on the human placenta.

Intergenerational transfer of micro(nano)plastics in different organisms

Micro(nano)plastics (MNPs), widely distributed in the environment, can be ingested and accumulated by various organisms. Recently, the transgenerational transport of MNPs from parental organisms to their offspring has attracted increasing attention. In this review, we summarize the patterns, specific pathways, and related mechanisms of intergenerational transfer of MNPs in plants, non-mammals (zooplankton and fish) and mammals. The knowledge gaps are also discussed. For plant, MNPs can accumulate in fruits and seeds by intercellular and cellular internalization pathways after uptake by roots or leaves. In zooplankton (e.g., Daphnia magna), MNPs are capable of maternal transfer via two different pathways: gut-ovary-egg and brood chamber-embryo. Intergenerational transfer of MNPs in egg-laying fish can occur through direct maternal transfer. However, MNPs may be transported through follicular pseudoplacenta, surface epithelia, and trophotaeniae pathways in ovoviviparous fish. In mammals, the maternal-fetal transport of MNPs primarily occurs through the placenta, amniotic fluid, and breastfeeding. The placental barrier is the main limitation to transfer, and the ability of MNPs to cross this barrier largely depends on the trophoblast cells via internalization and intercellular pathways. Additionally, we discuss the physicochemical properties (e.g., size, shape, and ageing) of MNPs and environmental factors (e.g., salinity, minerals, organic matter) that influence intergenerational transfer. Current challenges regarding the transfer pathways and related mechanisms, as well as future perspectives, are also addressed. This review provides valuable information for assessing the fate of MNPs in organisms and potential risks to population, community, ecosystems, and human health.

Gestational exposure to polystyrene microplastics incurred placental damage in mice: Insights into metabolic and gene expression disorders

As an emerging environmental pollutant, microplastics have attracted increasing attention to their potential health hazards. However, the current understanding about the toxicity and health implications, especially about developmental toxicity with exposure to microplastics is quite limited. In the current study, we aimed to scrutinize the deleterious effects of polystyrene microplastics (PSMPs) with different sizes (0.1 and 5 μm) on the placenta that plays crucial role in fetal development, following oral exposure during gestational stages. The results showed that two sizes of PSMPs could distribute in mouse placental tissues, and nanosized PSMPs (0.1 μm) exhibited greater capability to penetrate the placenta and deposit in the liver and brain of fetuses than microsized PSMPs (5 μm). Importantly, only 0.1 μm PSMPs induced a decrease in the junctional area, a reduction in the labyrinthine vascularization and an increase in cell apoptosis in the placenta, accompanied by fetal developmental impairments. The results of metabolome and transcriptome uncovered that 0.1 μm PSMP exposure caused changes in metabolic and gene profiles of placental tissues, across multiple pathways such as vascular supply, nutrient absorption and transportation and amino acid metabolism. Overall, our results confirmed that maternal PSMP exposure led to placental damages associated with metabolic and gene expression disorders. This study would provide new insights into the developmental impacts of microplastic consumption during gestation.

Elevated Micro- and Nanoplastics Detected in Preterm Human Placentae

Recent analytical advancements have uncovered increasing micro- and nanoplastics (MNPs) in environmental, dietary, and biological domains, raising concerns about their health impacts. Preterm birth (PTB), a leading cause of maternal and neonatal morbidity and mortality, may be influenced by MNP exposure, yet this relationship remains unexplored. This study quantified 12 MNP polymers in placentae from term (n=87) and preterm (n=71) deliveries using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS). Cumulative MNP concentrations were 28% higher in PTB placentae (mean ±SD: 224.7 ± 180.7 μg/g vs. 175.5 ± 137.9 μg/g; p=0.038). Polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyurethane (PU), and polycarbonate (PC) were significantly elevated in PTB, and PET, PU, and PC inversely correlated with gestational age and birth weight. Logistic regression identified PVC and PC as independent predictors of PTB. These findings suggest total and specific MNPs are associated with PTB, providing actionable insights and emphasizing the importance of minimizing exposure during pregnancy.

Can Mammalian Reproductive Health Withstand Massive Exposure to Polystyrene Micro- and Nanoplastic Derivatives? A Systematic Review

The widespread use of plastics has increased environmental pollution by micro- and nanoplastics (MNPs), especially polystyrene micro- and nanoplastics (PS-MNPs). These particles are persistent, bioaccumulative, and linked to endocrine-disrupting toxicity, posing risks to reproductive health. This review examines the effects of PS-MNPs on mammalian reproductive systems, focusing on oxidative stress, inflammation, and hormonal imbalances. A comprehensive search in the Web of Science Core Collection, following PRISMA 2020 guidelines, identified studies on the impact of PS-MNPs on mammalian fertility, including oogenesis, spermatogenesis, and folliculogenesis. An analysis of 194 publications revealed significant reproductive harm, such as reduced ovarian size, depleted follicular reserves, increased apoptosis in somatic cells, and disrupted estrous cycles in females, along with impaired sperm quality and hormonal imbalances in males. These effects were linked to endocrine disruption, oxidative stress, and inflammation, leading to cellular and molecular damage. Further research is urgently needed to understand PS-MNPs toxicity mechanisms, develop interventions, and assess long-term reproductive health impacts across generations, highlighting the need to address these challenges given the growing environmental exposure.

Concerning influences of micro/nano plastics on female reproductive health: focusing on cellular and molecular pathways from animal models to human studies

The female reproductive system can face serious disorders and show reproductive abnormalities under the influence of environmental pollutants. Microplastics (MPs) and nanoplastics (NPs) as emerging pollutants, by affecting different components of this system, may make female fertility a serious challenge. Animal studies have demonstrated that exposure to these substances weakens the function of ovaries and causes a decrease in ovarian reserve capacity. Also, continuous exposure to micro/nano plastics (MNPs) leads to increased levels of reactive oxygen species, induction of oxidative stress, inflammatory responses, apoptosis of granulosa cells, and reduction of the number of ovarian follicles. Furthermore, by interfering with the hypothalamic-pituitary-ovarian axis, these particles disturb the normal levels of ovarian androgens and endocrine balance and delay the growth of gonads. Exposure to MNPs can accelerate carcinogenesis in the female reproductive system in humans and animal models. Animal studies have determined that these particles can accumulate in the placenta, causing metabolic changes, disrupting the development of the fetus, and endangering the health of future generations. In humans, the presence of micro/nanoplastics in placenta tissue, infant feces, and breast milk has been reported. These particles can directly affect the health of the mother and fetus, increasing the risk of premature birth and other pregnancy complications. This review aims to outline the hazardous effects of micro/nano plastics on female reproductive health and fetal growth and discuss the results of animal experiments and human research focusing on cellular and molecular pathways.

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.

Rational Design of Nanomedicine for Placental Disorders: Birthing a New Era in Women's Reproductive Health

The placenta is a transient organ that forms during pregnancy and acts as a biological barrier, mediating exchange between maternal and fetal circulation. Placental disorders, such as preeclampsia, fetal growth restriction, placenta accreta spectrum, and gestational trophoblastic disease, originate in dysfunctional placental development during pregnancy and can lead to severe complications for both the mother and fetus. Unfortunately, treatment options for these disorders are severely lacking. Challenges in designing therapeutics for use during pregnancy involve selectively delivering payloads to the placenta while protecting the fetus from potential toxic side effects. Nanomedicine holds great promise in overcoming these barriers; the versatile and modular nature of nanocarriers, including prolonged circulation times, intracellular delivery, and organ-specific targeting, can control how therapeutics interact with the placenta. In this review, nanomedicine strategies are discussed to treat and diagnose placental disorders with an emphasis on understanding the unique pathophysiology behind each of these diseases. Finally, prior study of the pathophysiologic mechanisms underlying these placental disorders has revealed novel disease targets. These targets are highlighted here to motivate the rational design of precision nanocarriers to improve therapeutic options for placental disorders.

Ulgen K. Advances in Physiologically Based Pharmacokinetic (PBPK) Modeling of Nanomaterials

Nanoparticles (NPs) have been widely used to improve the pharmacokinetic properties and tissue distribution of small molecules such as targeting to a specific tissue of interest, enhancing their systemic circulation, and enlarging their therapeutic properties. NPs have unique and complicated in vivo disposition properties compared to small molecule drugs due to their complex multifunctionality. Physiologically based pharmacokinetic (PBPK) modeling has been a powerful tool in the simulation of the absorption, distribution, metabolism, and elimination (ADME) characteristics of the materials, and it can be used in the characterization and prediction of the systemic disposition, toxicity, efficacy, and target exposure of various types of nanoparticles. In this review, recent advances in PBPK model applications related to the nanoparticles with unique properties, and dispositional features in the biological systems, ADME characteristics, the description of transport processes of nanoparticles in the PBPK model, and the challenges in PBPK model development of nanoparticles are delineated and juxtaposed with those encountered in small molecule models. Nanoparticle related, non-nanoparticle-related, and interspecies-scaling methods applied in PBPK modeling are reviewed. In vitro to in vivo extrapolation (IVIVE) methods being a promising computational tool to provide in vivo predictions from the results of in vitro and in silico studies are discussed. Finally, as a recent advancement ML/AI-based approaches and challenges in PBPK modeling in the estimation of ADME parameters and pharmacokinetic (PK) analysis results are introduced.

A review on micro- and nanoplastics in humans: Implication for their translocation of barriers and potential health effects

As emerging contaminants, micro- and nanoplastics (MNPs) can absorb and leach various toxic chemicals and ultimately endanger the health of the ecological environment and humans. With extensive research on MNPs, knowledge about MNPs in humans, especially their translocation of barriers and potential health effects, is of utmost importance. In this review, we collected literature published from 2000 to 2023, focusing on MNPs on their occurrence in humans, penetrating characteristics in the placental, blood-brain, and blood-testis barriers, and exposure effects on mammalian health. The characteristics and distributions of MNPs in human samples were analyzed, and the results demonstrated that MNPs were ubiquitous in most human samples, except for kidneys and cerebrospinal fluid. In addition, the phenomenon of MNPs crossing barriers and their underlying mechanisms were discussed. We also summarized the potential factors that may affect the barrier crossing and health effects of MNPs, including characteristics of MNPs, exposure doses, administration routes, exposure durations, co-exposure to other pollutants, and genetic predisposition. Exposure to MNPs may cause cytotoxicity, neurotoxicity, and developmental and reproductive toxicity in mammals. People are encouraged to reduce their exposure to MNPs to prevent these adverse health effects. Finally, we discussed the shortcomings of current research on MNPs in humans, providing a valuable reference for understanding and evaluating the potential health risks from MNP exposure in mammals, including humans.

Exposure to fine particulate matter 2.5 from wood combustion smoke causes vascular changes in placenta and reduce fetal size

During gestation, maternal blood flow to the umbilical cord and placenta increases, facilitating efficient nutrient absorption, waste elimination, and effective gas exchange for the developing fetus. However, the effects of exposure to wood smoke during this period on these processes are unknown. We hypothesize that exposure to PM2.5, primarily sourced from wood combustion for home heating, affects placental vascular morphophysiology and fetal size. We used exposure chambers that received either filtered or unfiltered air. Female rats were exposed to PM2.5 during pre-gestational and/or gestational stages. Twenty-one days post-fertilization, placentas were collected via cesarean section. In these placentas, oxygen diffusion capacity was measured, and the expression of angiogenic factors was analyzed using qPCR and immunohistochemistry. In groups exposed to PM2.5 during pre-gestational and/or gestational stages, a decrease in fetal weight, crown-rump length, theoretical and specific diffusion capacity, and an increase in HIF-1α expression were observed. In groups exposed exclusively to PM2.5 during the pre-gestational stage, there was an increase in the expression of placental genes Flt-1, Kdr, and PIGF. Additionally, in the placental labyrinth region, the expression of angiogenic factors was elevated. Changes in angiogenesis and angiogenic factors reflect adaptations to hypoxia, impacting fetal growth and oxygen supply. In conclusion, this study demonstrates that exposure to PM2.5, emitted from wood smoke, in both pre-gestational and gestational stages, affects fetal development and placental health. This underscores the importance of addressing air pollution in areas with high levels of wood smoke, which poses a significant health risk to pregnant women and their fetuses.

Understanding the impact of nanoplastics on reproductive health: Exposure pathways, mechanisms, and implications

Microplastic pollution is a pressing global environmental concern with particular urgency surrounding the issue of nanoplastic particles. Plastic products exhibit a remarkable persistence in natural ecosystems, resisting easy degradation. Nanoplastics, characterized by their diminutive size, possess distinct properties when compared to their larger counterparts, which could potentially render them more ecologically detrimental. Microplastics themselves serve as carriers for toxic and hazardous substances, such as plastic additives, that enter and persist in the environmental cycle. Importantly, nanoplastics exhibit enhanced bioavailability upon entering the food chain. Notably, studies have demonstrated the adverse effects of nanoplastics on the reproductive function of aquatic organisms, and evidence of micro- and nanoplastics have emerged within human reproductive organs, including the placenta. However, a knowledge gap persists regarding the impacts of nanoplastics on the reproductive systems of mammals and, indeed, humans. This paper aims to elucidate the less frequently discussed sources and distribution of nanoplastics in the environment, along with the pathways of human exposure. We also emphasize the extent to which nanoplastics accumulate within the reproductive systems of organisms. Subsequently, we present an in-depth analysis of the effects of nanoplastics and their associated contaminants on mammalian and human reproductive health. The mechanisms through which nanoplastics contribute to reproductive disorders are comprehensively explored, highlighting their potential to disrupt endocrine levels in mammals and humans. Additionally, we scrutinize and discuss studies on biotoxicity of nanoplastics, offering insights into potential areas for future research.

Exposure to high dose of polystyrene nanoplastics causes trophoblast cell apoptosis and induces miscarriage

BACKGROUND

With rapid increase in the global use of various plastics, microplastics (MPs) and nanoplastics (NPs) pollution and their adverse health effects have attracted global attention. MPs have been detected out in human body and both MPs and NPs showed female reproductive toxicological effects in animal models. Miscarriage (abnormal early embryo loss), accounting for 15-25% pregnant women worldwide, greatly harms human reproduction. However, the adverse effects of NPs on miscarriage have never been explored.

RESULTS

In this study, we identified that polystyrene (PS) plastics particles were present in women villous tissues. Their levels were higher in villous tissues of unexplained recurrent miscarriage (RM) patients vs. healthy control (HC) group. Furthermore, mouse assays further confirmed that exposure to polystyrene nanoplastics (PS-NPs, 50 nm in diameter, 50 or 100 mg/kg) indeed induced miscarriage. In mechanism, PS-NPs exposure (50, 100, 150, or 200 µg/mL) increased oxidative stress, decreased mitochondrial membrane potential, and increased apoptosis in human trophoblast cells by activating Bcl-2/Cleaved-caspase-2/Cleaved-caspase-3 signaling through mitochondrial pathway. The alteration in this signaling was consistent in placental tissues of PS-NPs-exposed mouse model and in villous tissues of unexplained RM patients. Supplement with Bcl-2 could efficiently suppress apoptosis in PS-NPs-exposed trophoblast cells and reduce apoptosis and alleviate miscarriage in PS-NPs-exposed pregnant mouse model.

CONCLUSIONS

Exposure to PS-NPs activated Bcl-2/Cleaved-caspase-2/Cleaved-caspase-3, leading to excessive apoptosis in human trophoblast cells and in mice placental tissues, further inducing miscarriage.

Microplastics exposure: implications for human fertility, pregnancy and child health

Plastics found in our everyday environment are becoming an increasing concern for individual and population-level health, and the extent of exposure and potential toxic effects of these contaminants on numerous human organ systems are becoming clear. Microplastics (MPs), tiny plastic particles, appear to have many of the same biological effects as their plastic precursors and have the compounded effect of potential accumulation in different organs. Recently, microplastic accumulation was observed in the human placenta, raising important questions related to the biological effects of these contaminants on the health of pregnancies and offspring. These concerns are particularly heightened considering the developmental origins of health and disease (DOHaD) framework, which postulates that in utero exposure can programme the lifelong health of the offspring. The current review examines the state of knowledge on this topic and highlights important avenues for future investigation.

Advance in placenta drug delivery: concern for placenta-originated disease therapy

In the therapy of placenta-originated diseases during pregnancy, the main challenges are fetal exposure to drugs, which can pass through the placenta and cause safety concerns for fetal development. The design of placenta-resident drug delivery system is an advantageous method to minimize fetal exposure as well as reduce adverse maternal off-target effects. By utilizing the placenta as a biological barrier, the placenta-resident nanodrugs could be trapped in the local placenta to concentrate on the treatment of this abnormal originated tissue. Therefore, the success of such systems largely depends on the placental retention capacity. This paper expounds on the transport mechanism of nanodrugs in the placenta, analyzes the factors that affect the placental retention of nanodrugs, and summarizes the advantages and concerns of current nanoplatforms in the treatment of placenta-originated diseases. In general, this review aims to provide a theoretical basis for the construction of placenta-resident drug delivery systems, which will potentially enable safe and efficient clinical treatment for placenta-originated diseases in the future.

Nanoparticles at the maternal-fetal interface

The increasing production of intentional and unintentional nanoparticles (NPs) has led to their accumulation in the environment as air and ground pollution. The heterogeneity of these particles primarily relies on the NP physicochemical properties (i.e., chemical composition, size, shape, surface chemistry, etc.). Pregnancy represents a vulnerable life stage for both the woman and the developing fetus. The ubiquitous nature of these NPs creates a concern for developmental fetal exposures. At the maternal-fetal interface lies the placenta, a temporary endocrine organ that facilitates nutrient and waste exchange as well as communication between maternal and fetal tissues. Recent evidence in human and animal models identifies that gestational exposure to NPs results in placental translocation leading to local effects and endocrine disruption. Currently, the mechanisms underlying placental translocation and cellular uptake of NPs in the placenta are poorly understood. The purpose of this review is to assess the current understanding of the physiochemical factors influencing NP translocation, cellular uptake, and endocrine disruption at the maternal-fetal interface within the available literature.

Journey of micronanoplastics with blood components

The entry of micro- and nanoplastics (MNPs) into the human body is inevitable. They enter blood circulation through ingestion, inhalation, and dermal contact by crossing the gut-lung-skin barrier (the epithelium of the digestive tract, the respiratory tract, and the cutaneous layer). There are many reports on their toxicities to organs and tissues. This paper presents the first thorough assessment of MNP-driven bloodstream toxicity and the mechanism of toxicity from the viewpoint of both MNP and environmental co-pollutant complexes. Toxic impacts include plasma protein denaturation, hemolysis, reduced immunity, thrombosis, blood coagulation, and vascular endothelial damage, among others, which can lead to life-threatening diseases. Protein corona formation, oxidative stress, cytokine alterations, inflammation, and cyto- and genotoxicity are the key mechanisms involved in toxicity. MNPs change the secondary structure of plasma proteins, thereby preventing their transport functions (for nutrients, drugs, oxygen, etc.). MNPs inhibit erythropoiesis by influencing hematopoietic stem cell proliferation and differentiation. They cause red blood cell and platelet aggregation, as well as increased adherence to endothelial cells, which can lead to thrombosis and cardiovascular disease. White blood cells and immune cells phagocytose MNPs, provoking inflammation. However, research gaps still exist, including gaps regarding the combined toxicity of MNPs and co-pollutants, toxicological studies in human models, advanced methodologies for toxicity analysis, bioaccumulation studies, inflammation and immunological responses, dose-response relationships of MNPs, and the effect of different physiochemical characteristics of MNPs. Furthermore, most studies have analyzed toxicity using prepared MNPs; hence, studies must be undertaken using true-to-life MNPs to determine the real-world scenario. Additionally, nanoplastics may further degrade into monomers, whose toxic effects have not yet been explored. The research gaps highlighted in this review will inspire future studies on the toxicity of MNPs in the vascular/circulatory systems utilizing in vivo models to enable more reliable health risk assessment.

Micro- and nanoplastics (MNPs) and their potential toxicological outcomes: State of science, knowledge gaps and research needs

Plastic waste has been produced at a rapidly growing rate over the past several decades. The environmental impacts of plastic waste on marine and terrestrial ecosystems have been recognized for years. Recently, researchers found that micro- and nanoplastics (MNPs), micron (100 nm - 5 mm) and nanometer (1 - 100 nm) scale particles and fibers produced by degradation and fragmentation of plastic waste in the environment, have become an important emerging environmental and food chain contaminant with uncertain consequences for human health. This review provides a comprehensive summary of recent findings from studies of potential toxicity and adverse health impacts of MNPs in terrestrial mammals, including studies in both in vitro cellular and in vivo mammalian models. Also reviewed here are recently released biomonitoring studies that have characterized the bioaccumulation, biodistribution, and excretion of MNPs in humans. The majority MNPs in the environment to which humans are most likely to be exposed, are of irregular shapes, varied sizes, and mixed compositions, and are defined as secondary MNPs. However, the MNPs used in most toxicity studies to date were commercially available primary MNPs of polystyrene (PS), polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), and other polymers. The emerging in vitro and in vivo evidence reviewed here suggests that MNP toxicity and bioactivity are largely determined by MNP particle physico-chemical characteristics, including size, shape, polymer type, and surface properties. For human exposure, MNPs have been identified in human blood, urine, feces, and placenta, which pose potential health risks. The evidence to date suggests that the mechanisms underlying MNP toxicity at the cellular level are primarily driven by oxidative stress. Nonetheless, large knowledge gaps in our understanding of MNP toxicity and the potential health impacts of MNP exposures still exist and much further study is needed to bridge those gaps. This includes human population exposure studies to determine the environmentally relevant MNP polymers and exposure concentrations and durations for toxicity studies, as well as toxicity studies employing environmentally relevant MNPs, with surface chemistries and other physico-chemical properties consistent with MNP particles in the environment. It is especially important to obtain comprehensive toxicological data for these MNPs to understand the range and extent of potential adverse impacts of microplastic pollutants on humans and other organisms.

Toxicity of microplastics and nanoplastics: invisible killers of female fertility and offspring health

Microplastics (MPs) and nanoplastics (NPs) are emergent pollutants, which have sparked widespread concern. They can infiltrate the body via ingestion, inhalation, and cutaneous contact. As such, there is a general worry that MPs/NPs may have an impact on human health in addition to the environmental issues they engender. The threat of MPs/NPs to the liver, gastrointestinal system, and inflammatory levels have been thoroughly documented in the previous research. With the detection of MPs/NPs in fetal compartment and the prevalence of infertility, an increasing number of studies have put an emphasis on their reproductive toxicity in female. Moreover, MPs/NPs have the potential to interact with other contaminants, thus enhancing or diminishing the combined toxicity. This review summarizes the deleterious effects of MPs/NPs and co-exposure with other pollutants on female throughout the reproduction period of various species, spanning from reproductive failure to cross-generational developmental disorders in progenies. Although these impacts may not be directly extrapolated to humans, they do provide a framework for evaluating the potential mechanisms underlying the reproductive toxicity of MPs/NPs.

Determinants and mechanisms of inorganic nanoparticle translocation across mammalian biological barriers

Biological barriers protect delicate internal tissues from exposures to and interactions with hazardous materials. Primary anatomical barriers prevent external agents from reaching systemic circulation and include the pulmonary, gastrointestinal, and dermal barriers. Secondary barriers include the blood-brain, blood-testis, and placental barriers. The tissues protected by secondary barriers are particularly sensitive to agents in systemic circulation. Neurons of the brain cannot regenerate and therefore must have limited interaction with cytotoxic agents. In the testis, the delicate process of spermatogenesis requires a specific milieu distinct from the blood. The placenta protects the developing fetus from compounds in the maternal circulation that would impair limb or organ development. Many biological barriers are semi-permeable, allowing only materials or chemicals, with a specific set of properties, that easily pass through or between cells. Nanoparticles (particles less than 100 nm) have recently drawn specific concern due to the possibility of biological barrier translocation and contact with distal tissues. Current evidence suggests that nanoparticles translocate across both primary and secondary barriers. It is known that the physicochemical properties of nanoparticles can affect biological interactions, and it has been shown that nanoparticles can breach primary and some secondary barriers. However, the mechanism by which nanoparticles cross biological barriers has yet to be determined. Therefore, the purpose of this review is to summarize how different nanoparticle physicochemical properties interact with biological barriers and barrier products to govern translocation.

Modulation of engineered nanomaterial interactions with organ barriers for enhanced drug transport

The biomedical use of nanoparticles (NPs) has been the focus of intense research for over a decade. As most NPs are explored as carriers to alter the biodistribution, pharmacokinetics and bioavailability of associated drugs, the delivery of these NPs to the tissues of interest remains an important topic. To date, the majority of NP delivery studies have used tumor models as their tool of interest, and the limitations concerning tumor targeting of systemically administered NPs have been well studied. In recent years, the focus has also shifted to other organs, each presenting their own unique delivery challenges to overcome. In this review, we discuss the recent advances in leveraging NPs to overcome four major biological barriers including the lung mucus, the gastrointestinal mucus, the placental barrier, and the blood-brain barrier. We define the specific properties of these biological barriers, discuss the challenges related to NP transport across them, and provide an overview of recent advances in the field. We discuss the strengths and shortcomings of different strategies to facilitate NP transport across the barriers and highlight some key findings that can stimulate further advances in this field.

Reproductive toxicity of microplastics in female mice and their offspring from induction of oxidative stress

Microplastics (MPs) are an emerging pollutant that is becoming recognized as an increasingly serious environmental problem. The biological toxicity and resulting health risks of MPs have attracted much attention in the research community. While the effects of MPs on various mammalian organ systems have been described, their interactions with oocytes and the underlying mechanism of their activity within the reproductive system have remained ambiguous. Here, we discovered that oral administration of MPs to mice (40 mg/kg per day for 30 days) significantly reduced the oocyte maturation and fertilization rate, embryo development, and fertility. Ingestion of MPs significantly increased the ROS level in oocytes and embryos, leading to oxidative stress, mitochondrial dysfunction, and apoptosis. Moreover, mouse exposure to MPs caused DNA damage in oocytes, including spindle/chromosome morphology defects, and downregulation of actin and Juno expression in mouse oocytes. In addition, mice were also exposed to MPs (40 mg/kg per day) during gestation and lactation to determine trans-generational reproductive toxicity. The results showed that maternal exposure to MPs during pregnancy resulted in a decline in birth and postnatal body weight in offspring mice. Furthermore, MPs exposure of mothers markedly reduced oocyte maturation, fertilization rate, and embryonic development in their female offspring. This investigation provides new insights on the mechanism of MPs' reproductive toxicity and raises concerns for potential risks of MP pollution on the reproductive health of humans and animals.

A Systematic Review of the Placental Translocation of Micro- and Nanoplastics

PURPOSE OF REVIEW

Despite increasing awareness of the ubiquity of microplastics (MPs) in our environments, little is known about their risk of developmental toxicity. Even less is known about the environmental distribution and associated toxicity of nanoplastics (NPs). Here, we review the current literature on the capacity for MPs and NPs to be transported across the placental barrier and the potential to exert toxicity on the developing fetus.

RECENT FINDINGS

This review includes 11 research articles covering in vitro, in vivo, and ex vivo models, and observational studies. The current literature confirms the placental translocation of MPs and NPs, depending on physicochemical properties such as size, charge, and chemical modification as well as protein corona formation. Specific transport mechanisms for translocation remain unclear. There is emerging evidence of placental and fetal toxicity due to plastic particles based on animal and in vitro studies. Nine out of eleven studies examined in this review found that plastic particles were capable of placental translocation. In the future, more studies are needed to confirm and quantify the existence of MPs and NPs in human placentas. Additionally, translocation of different plastic particle types and heterogenous mixtures across the placenta, exposure at different periods of gestation, and associations with adverse birth and other developmental outcomes should also be investigated.

Experimental human placental models for studying uptake, transport and toxicity of micro- and nanoplastics

Micro- and nanoplastics (MNPs) are ubiquitous in the environment and have recently been found in human lungs, blood and placenta. However, data on the possible effects of MNPs on human health is extremely scarce. The potential toxicity of MNPs during pregnancy, a period of increased susceptibility to environmental insults, is of particular concern. The placenta provides a unique interface between maternal and fetal circulation which is essential for in utero survival and healthy pregnancy. Placental toxicokinetics and toxicity of MNPs are still largely unexplored and the limited studies performed up to now focus mainly on polystyrene particles. Practical and ethical considerations limit research options in humans, and extrapolation from animal studies is challenging due to marked differences between species. Nevertheless, diverse in vitro and ex vivo human placental models exist e.g., plasma membrane vesicles, mono-culture and co-culture of placental cells, placenta-on-a-chip, villous tissue explants, and placental perfusion that can be used to advance this research area. The objective of this concise review is to recapitulate different human placental models, summarize the current understanding of placental uptake, transport and toxicity of MNPs and define knowledge gaps. Moreover, we provide perspectives for future research urgently needed to assess the potential hazards and risks of MNP exposure to maternal and fetal health.

Toxicity of polystyrene nanoparticles for mouse ovary and cultured human granulosa cells

The issue of global environmental contamination of microplastics has recently been receiving widespread attention. However, the effects of polystyrene nanoparticles (Nano-PS) on the female reproductive system remain unclear. We investigated the toxicity and explored the potential underlying mechanisms of Nano-PS in both mouse ovarian tissue in vivo and human ovarian granulosa cell lines in vitro. In vivo experiments: Mice were fed different concentrations of Nano-PS for 8 weeks. In vitro experiments: COV434 cells were treated with increasing concentrations of Nano-PS. In the present study, ovarian reserve was found to decrease significantly, while oxidative stress and apoptosis levels increased. Nano-PS increased the proportion of metestrum and diestrus periods, and decreased the proportion of estrous period. The implantation rates and the number of pups per litter decreased. In COV434 cells, Nano-PS reduced cell viability and mitochondrial membrane potential, increased the expression of apoptotic and oxidative stress markers and led to subsequent cell cycle arrest. Specifically, Nano-PS exert their toxic effects on mouse ovarian tissue and COV434 cells by inducing oxidative stress. A potential strategy to overcome this could be to activate the nuclear factor-E2-related factor 2 (Nrf2) signaling pathway to mitigate Nano-PS-induced oxidative stress.

Dietary Antioxidant Curcumin Mitigates CuO Nanoparticle-Induced Cytotoxicity through the Oxidative Stress Pathway in Human Placental Cells

The placenta is an important organ that maintains a healthy pregnancy by transporting nutrients to the fetus and removing waste from the fetus. It also acts as a barrier to protect the fetus from hazardous materials. Recent studies have indicated that nanoparticles (NPs) can cross the placental barrier and pose a health risk to the developing fetus. The high production and widespread application of copper oxide (CuO) NPs may lead to higher exposure to humans, raising concerns of health hazards, especially in vulnerable life stages, e.g., pregnancy. Oxidative stress plays a crucial role in the pathogenesis of adverse pregnancy outcomes. Due to its strong antioxidant activity, dietary curcumin can act as a therapeutic agent for adverse pregnancy. There is limited knowledge on the hazardous effects of CuO NPs during pregnancy and their mitigation by curcumin. This study aimed to investigate the preventive effect of curcumin against CuO NP-induced toxicity in human placental (BeWo) cells. CuO NPs were synthesized by a facile hydrothermal process and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence techniques. We observed that curcumin did not induce toxicity in BeWo cells (1-100 µg/mL for 24 h), whereas CuO NPs decreased the cell viability dose-dependently (5-200 µg/mL for 24 h). Interestingly, CuO NP-induced cytotoxicity was effectively mitigated by curcumin co-exposure. The apoptosis data also exhibited that CuO NPs modulate the expression of several genes (p53, bax, bcl-2, casp3, and casp9), the activity of enzymes (caspase-3 and -9), and mitochondrial membrane potential loss, which was successfully reverted by co-treatment with curcumin. The mechanistic study suggested that CuO-induced reactive oxygen species generation, lipid peroxidation, and higher levels of hydrogen peroxide were significantly alleviated by curcumin co-exposure. Moreover, glutathione depletion and the lower activity of antioxidant enzymes (superoxide dismutase, glutathione peroxidase, and catalase) were effectively mitigated by curcumin. We believe this is the first report exhibiting that CuO-induced toxicity in BeWo cells can be effectively alleviated by curcumin. The pharmacological potential of dietary curcumin in NP-induced toxicity during pregnancy warrants further investigation.

Placental Models for Evaluation of Nanocarriers as Drug Delivery Systems for Pregnancy Associated Disorders

Pregnancy-associated disorders affect around 20% of pregnancies each year around the world. The risk associated with pregnancy therapeutic management categorizes pregnant women as "drug orphan" patients. In the last few decades, nanocarriers have demonstrated relevant properties for controlled drug delivery, which have been studied for pregnancy-associated disorders. To develop new drug dosage forms it is mandatory to have access to the right evaluation models to ensure their usage safety and efficacy. This review exposes the various placental-based models suitable for nanocarrier evaluation for pregnancy-associated therapies. We first review the current knowledge about nanocarriers as drug delivery systems and how placenta can be used as an evaluation model. Models are divided into three categories: in vivo, in vitro, and ex vivo placental models. We then examine the recent studies using those models to evaluate nanocarriers behavior towards the placental barrier and which information can be gathered from these results. Finally, we propose a flow chart on the usage and the combination of models regarding the nanocarriers and nanoparticles studied and the intended therapeutic strategy.

Maternal exposure to polystyrene nanoplastics during gestation and lactation induces hepatic and testicular toxicity in male mouse offspring

Nanoplastics have raised considerable concerns since their ubiquity in the environment and potential hazard to health. It has been proven that polystyrene nanoparticles (PS-NPs) can be maternally transferred to the offspring. In this study, mice were exposed gestationally and lactationally to PS-NPs (size 100 nm) at different doses (0.1, 1 and 10 mg/L) to investigate the trans-generational poisonousness. Our data illustrated that maternal PS-NPs exposure in pregnancy and lactation resulted in a decline in birth and postnatal body weight in offspring mice. Furthermore, high-dose PS-NPs reduced liver weight, triggered oxidative stress, caused inflammatory cell infiltration, up-regulated proinflammatory cytokine expression, and disturbed glycometabolism in the liver of male offspring mice. In addition, pre- and postnatal PS-NPs exposure diminished testis weight, disrupted seminiferous epithelium and decreased sperm count in mouse offspring. Moreover, PS-NPs induced testicular oxidative injury, as presented by increased malondialdehyde generation and altered superoxide dismutase and catalase activities in the testis of offspring mice. These findings declared that maternal exposure to PS-NPs in pregnancy and lactation can cause hepatic and testicular toxicity in male mouse pups, which put forward new understanding into the detrimental effects of nanoplastics on mammalian offspring.

A Children's Health Perspective on Nano- and Microplastics

BACKGROUND

Pregnancy, infancy, and childhood are sensitive windows for environmental exposures. Yet the health effects of exposure to nano- and microplastics (NMPs) remain largely uninvestigated or unknown. Although plastic chemicals are a well-established research topic, the impacts of plastic particles are unexplored, especially with regard to early life exposures.

OBJECTIVES

This commentary aims to summarize the knowns and unknowns around child- and pregnancy-relevant exposures to NMPs via inhalation, placental transfer, ingestion and breastmilk, and dermal absorption.

METHODS

A comprehensive literature search to map the state of the science on NMPs found 37 primary research articles on the health relevance of NMPs during early life and revealed major knowledge gaps in the field. We discuss opportunities and challenges for quantifying child-specific exposures (e.g., NMPs in breastmilk or infant formula) and health effects, in light of global inequalities in baby bottle use, consumption of packaged foods, air pollution, hazardous plastic disposal, and regulatory safeguards. We also summarize research needs for linking child health and NMP exposures and address the unknowns in the context of public health action.

DISCUSSION

Few studies have addressed child-specific sources of exposure, and exposure estimates currently rely on generic assumptions rather than empirical measurements. Furthermore, toxicological research on NMPs has not specifically focused on child health, yet children's immature defense mechanisms make them particularly vulnerable. Apart from few studies investigating the placental transfer of NMPs, the physicochemical properties (e.g., polymer, size, shape, charge) driving the absorption, biodistribution, and elimination in early life have yet to be benchmarked. Accordingly, the evidence base regarding the potential health impacts of NMPs in early life remains sparse. Based on the evidence to date, we provide recommendations to fill research gaps, stimulate policymakers and industry to address the safety of NMPs, and point to opportunities for families to reduce early life exposures to plastic. https://doi.org/10.1289/EHP9086.

Toxicity of silver nanoparticles on Endometrial Receptivity in Female Mice

Nanoparticles (NPs) have many toxic effects on fertility and can prevent successful implantation by affecting the maternal uterine tissue. Herein, by deploying thirty female NMRI mice, the effect of silver nanoparticles on the endometrium and implantation has been investigated. Using spherical silver nanoparticles of a diameter of 18-30 nm at doses of 2 and 4 mg/kg, mice in both groups were treated. Then, female mice mated with male mice. Endometrial tissue was extracted 4.5 days later. On the fourth day of pregnancy, the mice were anesthetized and blood samples were taken from the heart; furthermore, endometrial tissue was isolated and used for molecular tests, ICP, and examination of pinopods. The results revealed that the levels of IL6 and IL1β and the accumulation of nanoparticles in endometrial tissue in the group receiving nanoparticles at a dose of 4 mg/kg had a major increase relative to the other two groups (p<0.05); group receiving a dose of 4 mg/kg, exhibited a decrease in pinopods and microvillus compared to the other two groups. According to the results, NPs can reach the endometrium, suggesting that caution should be exercised due to serious exposure to nanoparticles throughout pregnancy.

Gold nanoparticle biodistribution in pregnant mice following intravenous administration varies with gestational age

The use of nanoparticles (NPs) to deliver therapeutics to reproductive organs is an emerging approach to safely and effectively treat mothers and babies facing pregnancy complications. This study investigates the biodistribution of two different sized gold-based NPs in pregnant mice following systemic delivery as a function of gestational age. Poly(ethylene glycol)-coated 15 nm gold nanoparticles or 150 nm diameter silica core/gold nanoshells were intravenously administered to pregnant mice at gestational days (E)9.5 or 14.5. NP distribution was analyzed twenty-four hours later by inductively coupled plasma-mass spectrometry and silver staining of histological specimens. More NPs accumulated in placentas than embryos and delivery to these tissues was greater at E9.5 than E14.5. Neither NP type affected fetal weight or placental weight, indicating minimal short-term toxicity in early to mid-stage pregnancy. These findings warrant continued development of NPs as tools to deliver therapeutics to reproductive tissues safely.

Polystyrene nanoplastics exposure caused defective neural tube morphogenesis through caveolae-mediated endocytosis and faulty apoptosis

Growing evidence demonstrated that bioaccumulation of polystyrene nanoplastics (PS-NPs) in various organisms including human beings caused destructive effects on health. Nanoplastics may adversely affect fetal development potentially since they can pass through the placental barrier. However, very little has been known about the embryonic toxicity of polystyrene nanoplastics, especially in embryonic neurulation, the early developmental stage of the fetus, as well as the corresponding mechanisms. In this study, we first observed that 60- or 900-nm PS-NPs (especially 60-nm PS-NPs) could cross mouse placentas and affect developing mice fetuses. To avoid the indirect adverse effects derived from the restricted placenta, we employed early chick embryos as a developmental model to evaluate direct adverse effects of PS-NPs on embryo/fetal development, revealing suppressive effects on embryo development and an increased frequency of congenital abnormalities (especially in the nervous system), including neural tube defects. Thus, we focused on the potential negative effects of PS-NPs on neurulation, the earliest stage of nervous system development. Using caveolin-1 immunofluorescent staining of SH-SY5Y cells exposed to PS-NPs-GFP, we demonstrated that PS-NPs were internalized by SH-SY5Y cells via caveolae-mediated endocytosis. Transmission electron microscopy; LC3B immunofluorescent staining; and Atg7, Atg5, p62 and LC3B western blot results revealed that autophagy was activated in SH-SY5Y cells exposed to PS-NPs. However, PS-NPs were not degraded by the autophagic-lysosomal system given the lack of LAMP1 changes and minimal PS-NPs-GFP and LAMP1 colocalization. Furthermore, the cytoplasmic accumulation of PS-NPs caused faulty apoptotic cell death in SH-SY5Y cells and the developing neural tube as revealed by c-caspase3 immunofluorescent staining. Thus, defective neural tube morphogenesis, as demonstrated by neural tube defects, occurred during embryogenesis in the context of PS-NP exposure.

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.

Silver bionanoparticles toxicity in trophoblast is mediated by nitric oxide and glutathione pathways

Silver bionanoparticles (AgNPs) biosynthesized by Pseudomonas aeruginosa culture supernatant have an important antibacterial activity mediated by ROS increase; however their toxicity in human cells is not known. Due to the high susceptibility of the developing tissues to xenobiotics, the aim of this study was to investigate the AgNPs effect on first trimester human trophoblasts. The HTR8/SVneo cell line was treated with AgNPs (0.3-1.5 pM), for 6 and 24 h. Cell viability, reactive nitrogen and oxygen species (RNS and ROS) production, nitric oxide synthase expression, antioxidant defenses and biomolecule damage were evaluated. The exposure to AgNPs produced changes in HTR8/SVneo cell morphology and decreased cell viability. Alterations in redox balance were observed, with an increase in ROS and RNS levels, and NOS2 protein expression. Superoxide dismutase and catalase augmented their activity accompanied with a decreased in glutathione content and glutathione S-transferase activity. Protein oxidation and genotoxic damage were observed at concentrations greater than 0.6 pM. The pre-incubation with l-NMMA, NAC, mannitol and peroxidase demonstrated that AgNPs-induced cytotoxicity was not mediated by HO and H₂O₂, but nitric oxide and glutathione pathways were implicated in cell death. Since reported AgNPs microbicidal mechanism is mediated by increasing ROS (mainly HO and H₂O₂) without an increase in RNS, this work indicates an interesting difference in the reactive species and oxidative pathways involved in AgNPs toxicity in eukaryotic and prokaryotic cells. Highlighting the importance of toxicity evaluation to determine the safety of AgNPs with pharmaceutical potential uses.

Phenotyping placental oxygenation in Lgals1 deficient mice using 19F MRI

Placental hypoperfusion and hypoxia are key drivers in complications during fetal development such as fetal growth restriction and preeclampsia. In order to study the mechanisms of disease in mouse models, the development of quantitative biomarkers of placental hypoxia is a prerequisite. The goal of this exploratory study was to establish a technique to noninvasively characterize placental partial pressure of oxygen (PO2) in vivo in the Lgals1 (lectin, galactoside-binding, soluble, 1) deficient mouse model of preeclampsia using fluorine magnetic resonance imaging. We hypothesized a decrease in placental oxygenation in knockout mice. Wildtype and knockout animals received fluorescently labeled perfluoro-5-crown-15-ether nanoemulsion i.v. on day E14-15 during pregnancy. Placental PO2 was assessed via calibrated 19F MRI saturation recovery T1 mapping. A gas challenge with varying levels of oxygen in breathing air (30%, 60% and 100% O2) was used to validate that changes in oxygenation can be detected in freely breathing, anesthetized animals. At the end of the experiment, fluorophore-coupled lectin was injected i.v. to label the vasculature for histology. Differences in PO2 between breathing conditions and genotype were statistically analyzed with linear mixed-effects modeling. As expected, a significant increase in PO2 with increasing oxygen in breathing air was found. PO2 in Lgals1 knockout animals was decreased but this effect was only present at 30% oxygen in breathing air, not at 60% and 100%. Histological examinations showed crossing of the perfluorocarbon nanoemulsion to the fetal blood pool but the dominating contribution of 19F MR signal is estimated at > 70% from maternal plasma based on volume fraction measurements of previous studies. These results show for the first time that 19F MRI can characterize oxygenation in mouse models of placental malfunction.

Breakthrough of ZrO2 nanoparticles into fetal brains depends on developmental stage of maternal placental barrier and fetal blood-brain-barrier

Ingestion of nanoparticles may cause various damages to human body. However, how such ingestion by pregnant mother influences fetal development is not known because, presumably, ingested nanoparticles have to cross multiple biological barriers (such as intestinal and placental) to reach fetus. To answer this crucial question, here we investigated how a relatively biocompatible zirconia nanoparticles (ZrO₂ NPs, 16 nm) were translocated to fetal brains in three exposure models of pregnant mice: Model 1, oral exposure of nanoparticles before maternal blood-placental barrier (BPB) was fully developed; Model 2, exposures after BPB was developed, but before fetal blood-brain-barrier (BBB) was fully developed; Model 3, exposures after both maternal BPB and fetal BBB were fully developed. Our experimental results showed that translocation of ZrO₂ NPs into fetal brains was 55 % higher in Model 2 and 96 % higher in Model 1 compared with that in Model 3 after nanoparticles (50 mg/kg) were orally exposed to pregnant mice. Therefore, nanoparticles are able to cross multiple biological barriers and nanotoxicity to fetus is highly dependent on stages of pregnancy and fetal development or the maturity of multiple biological barriers. Oral exposures to nanoparticles during pregnancy are dangerous to fetal brain development, especially in early pregnancy.

Maternal PM2.5 exposure and abnormal placental nutrient transport

Epidemiological studies of human and animal experiments indicated that gestational exposure to atmospheric pollutants could be followed by the abnormal placental development. However, the effects of this exposure on the placental transportation for nutrients have not been systematically investigated. In this study, fine particulate matters (PM_2.5) samples were collected in Taiyuan and pregnant rodent models were administered with 3 mg/kg b.w. PM_2.5 by oropharyngeal aspiration every other day starting on embryonic day 0.5 (E0.5). Then the pregnant mice were sacrificed and their placentas were collected at different time points. The results showed that maternal PM_2.5 exposure (MPE) disrupted the expression of proliferating cell nuclear antigen (PCNA) at all time points and inhibited the cell proliferation in placenta. Following that, the capacity for placental nutrient transport was impaired. The changes at E18.5 were observed most significantly, showing the altered mRNA expression of amino acid, long-chain polyunsaturated fatty acid (LCPUFA), glucose and folate transporters. In addition, the glycogen content was elevated at E18.5, and the triglyceride content was increased at E13.5 and E15.5 and decreased at E18.5 in the placenta after MPE. In a word, the adverse effect induced by MPE revealed that MPE led tothe disruption on the nutrient supply to the developing fetus via modulating the abundance of placental nutrient transporters (PNT).

Translocation of (ultra)fine particles and nanoparticles across the placenta; a systematic review on the evidence of in vitro, ex vivo, and in vivo studies

Fetal development is a crucial window of susceptibility in which exposure may lead to detrimental health outcomes at birth and later in life. The placenta serves as a gatekeeper between mother and fetus. Knowledge regarding the barrier capacity of the placenta for nanoparticles is limited, mostly due to technical obstacles and ethical issues. We systematically summarize and discuss the current evidence and define knowledge gaps concerning the maternal-fetal transport and fetoplacental accumulation of (ultra)fine particles and nanoparticles. We included 73 studies on placental translocation of particles, of which 21 in vitro/ex vivo studies, 50 animal studies, and 2 human studies on transplacental particle transfer. This systematic review shows that (i) (ultra)fine particles and engineered nanoparticles can bypass the placenta and reach fetal units as observed for all the applied models irrespective of the species origin (i.e., rodent, rabbit, or human) or the complexity (i.e., in vitro, ex vivo, or in vivo), (ii) particle size, particle material, dose, particle dissolution, gestational stage of the model, and surface composition influence maternal-fetal translocation, and (iii) no simple, standardized method for nanoparticle detection and/or quantification in biological matrices is available to date. Existing evidence, research gaps, and perspectives of maternal-fetal particle transfer are highlighted.

Appropriate citation of placenta cell lines 3A(tPA-30-1) and 3A-sub E [post crisis of 3A(tPA-30-1)] in medical literature

Introduction

To determine how often placenta cell lines 3A (tPA-30-1) and 3A-sub E [post crisis of 3A (tPA-30-1)] are appropriately cited, or identified, as "term"-gestation placental cell lines in medical literature.

Methods

We performed a literature search on two databases, PubMed and One Search, using the terms "3A (tPA-30-1)," "3Asub-E," "3AsubE," "tPA-30-1," "tPA30-1," and "3A AND (placenta OR placental OR trophoblast OR trophoblastic) AND (cell OR line OR cell line)." Of the 218 citations retrieved, 181 were excluded due to duplication, article content irrelevance or lack of access to a full manuscript. The remaining 37 citations were thoroughly reviewed for 1)the presence of a full citation as designated by the supplier, and 2)the identification of the placental lines as "term."

Results

Of the 37 eligible citations included in the study, five demonstrated complete identifications of the placental cell lines of interest, while 32 demonstrated partial identifications that failed to match the designations provided by the manufacturer. Furthermore, of the 37 citations, eight accurately identified the cell lines as "term," while 27 lacked any description of gestational age, and two incorrectly identified them as "first trimester" cell lines. Overall, only three citations contained both a full citation and correct identification as a "term" placenta cell line.

Discussion

Only 5 of the 37 (13.5%) publications demonstrated a complete citation and only 8 publications accurately identified the gestational age of the placenta cell line as "term". Such findings confirm the need for a representative set of standards for the documentation of cell lines to improve the quality of publications in the scientific community.

The challenge of using nanotherapy during pregnancy: Technological aspects and biomedical implications

During the period of pregnancy, several processes and physiological adaptations occur in the body and metabolism of pregnant woman. These physiological adaptations in pregnant woman end up leading to a suppression in immune system favoring obstetric complications to the mother, fetus and placental tissue. An effective pharmacological therapy for these complications is still a challenge, since some drugs during pregnancy can have deleterious and teratogenic effects. An emerging alternative to pharmacological therapy during pregnancy is drugs encapsulated in nanoparticles (NP), recent area called nano-obstetrics. NP have the advantage of drug targeting and reduction of side effects. Then, maternal, placental or fetal uptake can be expected, depending on the characteristics of NP. Inorganic NP, crossing placental barrier effectively, but have several nanotoxicological effects. While organic NP appear to have a better targeting capacity and have few toxicological effects, but the studies are still scarce. Thus, in this review, were examined questions related to use and impact of physicochemical aspects of inorganic and organic NP during pregnancy.

Curcumin-loaded poly(ϵ-caprolactone) lipid-core nanocapsules: Evaluation of fetal and maternal toxicity

This study was designed to examine fetal and maternal toxicity of curcumin (CURC) loaded lipid-core nanocapsules (LNC) prepared with poly(ϵ-caprolactone) as a polymer, administered during the organogenesis period. Free CURC and CURC loaded-LNC (C-LNC) (2 mg/kg), blank LNC (B-LNC) and saline (CONTROL) were administered per oral route from the 7° to 13° gestational day (GD). Dams were evaluated daily for body weight gain, clinical signs, water and food intake. On 20° GD, dams were euthanized, organs were weighed and blood was collected for biochemical determinations. Fetal biometrics and external morphological anomalies were assessed. Also, were performed histopathological analysis of placenta and measurement of cytokines levels in placental and fetal liver tissues. All groups did not cause changes in dams during the pregnancy. Furthermore, treatments did not cause external morphological changes and delayed fetal development. Still, for histopathological analysis of placental tissue, treatments did not cause alterations in evaluated parameters. For cytokines levels, CURC and C-LNC caused a decrease in placental levels of TNF-α. Therefore, we have demonstrated that C-LNC did not cause toxicological effects (mother and fetus), in the same manner as pattern bioactive compound, proving to be a promising nutraceutical delivery system for maternal supplementation with CURC.

Nanotechnology-based Drug Delivery, Metabolism and Toxicity

BACKGROUND

Nanoparticles (NPs) are being used extensively owing to their increased surface area, targeted delivery and enhanced retention. NPs have the potential to be used in many disease conditions. Despite widespread use, their toxicity and clinical safety still remain a major concern.

OBJECTIVE

The purpose of this study was to explore the metabolism and toxicological effects of nanotherapeutics.

METHODS

Comprehensive, time-bound literature search was done covering the period from 2010 till date. The primary focus was on the metabolism of NP including their adsorption, degradation, clearance, and bio-persistence. This review also focuses on updated investigations on NPs with respect to their toxic effects on various in vitro and in vivo experimental models.

RESULTS

Nanotechnology is a thriving field of biomedical research and an efficient drug delivery system. Further their applications are under investigation for diagnosis of disease and as medical devices.

CONCLUSION

The toxicity of NPs is a major concern in the application of NPs as therapeutics. Studies addressing metabolism, side-effects and safety of NPs are desirable to gain maximum benefits of nanotherapeutics.

Recent insights on indirect mechanisms in developmental toxicity of nanomaterials

BACKGROUND

Epidemiological and animal studies provide compelling indications that environmental and engineered nanomaterials (NMs) pose a risk for pregnancy, fetal development and offspring health later in life. Understanding the origin and mechanisms underlying NM-induced developmental toxicity will be a cornerstone in the protection of sensitive populations and the design of safe and sustainable nanotechnology applications.

MAIN BODY

Direct toxicity originating from NMs crossing the placental barrier is frequently assumed to be the key pathway in developmental toxicity. However, placental transfer of particles is often highly limited, and evidence is growing that NMs can also indirectly interfere with fetal development. Here, we outline current knowledge on potential indirect mechanisms in developmental toxicity of NMs.

SHORT CONCLUSION

Until now, research on developmental toxicity has mainly focused on the biodistribution and placental translocation of NMs to the fetus to delineate underlying processes. Systematic research addressing NM impact on maternal and placental tissues as potential contributors to mechanistic pathways in developmental toxicity is only slowly gathering momentum. So far, maternal and placental oxidative stress and inflammation, activation of placental toll-like receptors (TLRs), impairment of placental growth and secretion of placental hormones, and vascular factors have been suggested to mediate indirect developmental toxicity of NMs. Therefore, NM effects on maternal and placental tissue function ought to be comprehensively evaluated in addition to placental transfer in the design of future studies of developmental toxicity and risk assessment of NM exposure during pregnancy.

Current Approaches and Techniques in Physiologically Based Pharmacokinetic (PBPK) Modelling of Nanomaterials

There have been efforts to develop physiologically based pharmacokinetic (PBPK) models for nanomaterials (NMs). Since NMs have quite different kinetic behaviors, the applicability of the approaches and techniques that are utilized in current PBPK models for NMs is warranted. Most PBPK models simulate a size-independent endocytosis from tissues or blood. In the lungs, dosimetry and the air-liquid interface (ALI) models have sometimes been used to estimate NM deposition and translocation into the circulatory system. In the gastrointestinal (GI) tract, kinetics data are needed for mechanistic understanding of NM behavior as well as their absorption through GI mucus and their subsequent hepatobiliary excretion into feces. Following absorption, permeability (P_t) and partition coefficients (PCs) are needed to simulate partitioning from the circulatory system into various organs. Furthermore, mechanistic modelling of organ- and species-specific NM corona formation is in its infancy. More recently, some PBPK models have included the mononuclear phagocyte system (MPS). Most notably, dissolution, a key elimination process for NMs, is only empirically added in some PBPK models. Nevertheless, despite the many challenges still present, there have been great advances in the development and application of PBPK models for hazard assessment and risk assessment of NMs.

Mild steel and stainless steel welding fumes elicit pro-inflammatory and pro-oxidant effects in first trimester trophoblast cells

Problem

As more women join the skilled‐trade workforce, the effects of workplace exposures on pregnancy need to be explored. This study aims to identify the effects of mild steel and stainless steel welding fume exposures on cultured placental trophoblast cells.

Method of study

Welding fumes (mild steel and stainless steel) were generously donated by Lincoln Electric. Electron microscopy was used to characterize welding fume particle size and the ability of particles to enter extravillous trophoblast cells (HTR‐8/SVneo). Cellular viability, free radical production, cytokine production, and ability of cells to maintain invasive properties were analyzed, respectively, by WST‐1, electron paramagnetic resonance, DCFH‐DA, V‐plex MULTI‐SPOT assay system, and a matrix gel invasion assay.

Results

For all three welding fume types, average particle size was <210 nm. HTR‐8/SVneo cells internalized welding particles, and nuclear condensation was observed. Cellular viability was significantly decreased at the high dose of 100 µg/mL for all three welding fumes, and stainless steel generated the greatest production of the hydroxyl radical, and intracellular reactive oxygen species. Production of the cytokines IL‐1β and TNFα were not observed in response to welding fume exposure, but IL‐6 and IL‐8 were. Finally, the invasive capability of cells was decreased upon exposure to both mild steel and stainless steel welding fumes.

Conclusion

Welding fumes are cytotoxic to extravillous trophoblasts, as is evident by the production of free radicals, pro‐inflammatory cytokines, and the observed decrease in invasive capabilities.

Toxicity of cooking oil fume derived particulate matter: Vitamin D3 protects tubule formation activation in human umbilical vein endothelial cells

Cooking oil fumes-derived PM_2.5 (COFs-derived PM_2.5) is the main source of indoor pollution. Exposure to COFs-derived PM_2.5 can cause oxidative stress and affect angiogenesis. Here we investigated the roles of vitamin D₃ (VD₃) in protecting tubule formation injury induced by COFs-derived PM_2.5, and the roles of ROS/NLRP3/VEGF signaling pathway in the effects. Human umbilical vein endothelial cells (HUVECs) were exposed to 0 (1‰ DMSO), 1000 nmol/l VD₃, 100 μg/ml PM_2.5, and 1000 nmol/l VD₃ + 100 μg/ml PM_2.5, respectively. Cell viability and tube formation, as well as protein and mRNA levels were measured. The results showed that exposure of COFs-derived PM_2.5 dose-and time-dependently reduced the viability of HUVECs, increased the levels of mitochondrial and intracellular ROS, and changed the mitochondrial membrane potential level. While co-incubation with VD₃ rescued these adverse effects. Both Western blot and real-time PCR (RT-PCR) showed that the expressions of NLRP3, caspase-1, Interleukin (IL)-1β, and IL-18 in COFs-derived PM_2.5 exposure group increased significantly, which could be effectively decreased by co-incubation with VD₃. COFs-derived PM_2.5 exposure could also reduce the expression of VEGF, while co-incubating HUVECs with VD₃ evidently up-regulated the protein level of VEGF in HUVECs. In addition, COFs-derived PM_2.5 could also inhibit the tube formation of HUVECs in vitro, which could be effectively rescued by the co-incubation of VD₃. Our study proved that COFs-derived PM_2.5 could damage the tubule formation of HUVECs in vitro, which could be effectively rescue by co-incubation with VD₃, in which processes the ROS/NLRP3/VEGF signaling pathway played a crucial role. It provides a new theoretical basis for further study on the toxicity of PM_2.5 to umbilical cord blood vessels.

Polystyrene nanoparticles may affect cell mitosis and compromise early embryo development in mammals

A great interest surrounds the development of nanoparticles (NPs) for biomedical applications such as drug delivery and cancer therapy. However, the interplay between nanoscale materials and biological systems and the associated hazards have not been completely clarified yet. In this study, bovine oviductal epithelial cells (BOECs) and embryos were used as in vitro models to investigate whether cell mitosis and early mammalian embryo development could be affected by the exposure to polystyrene (PS) nanoparticles. Analysis of the karyotype performed on BOECs exposed to PS-NPs did not show chromosomal anomalies compared to the control, although more tetraploid metaphase plates were observed in the former. In vitro fertilization experiments designed to understand whether exposure to PS-NPs could affect pre-implantation development showed that incubation with PS-NPs decreased 8-cell embryo and blastocyst rate in dose-dependent fashion. The quality of the blastocysts in terms of mean cell percent blastomeres with fragmented DNA was the same in exposed blastocysts compared to controls. These results show that the exposure to PS-NPs may impair development. In turn, this may affect the rate of mitosis in embryos and yield a lower developmental competence to reach the blastocyst stage. This suggests that release in the environment and the subsequent accumulation of PS-NPs into living organisms should be carefully monitored to prevent cytotoxic effects that may compromise their reproduction rates.

Gestational exposure to PM2.5 impairs vascularization of the placenta

The placenta is the bridge that connects the developing fetus and mother and is the place where nutrient uptake, waste elimination and gas exchange occurs. Epidemiological studies indicate that fetal stress, such as gestational PM_2.5 (particulate matter (PM) with diameter ≤ 2.5 μm) exposure, is a risk factor for abnormal placenta development that could induce adverse effects on the fetus. In the present study, PM samples were collected in Taiyuan. Then, pregnant C57BL/6 mice were treated with 3 mg/kg b.w. PM_2.5 every other day starting on GD0.5, and were sacrificed at embryonic day 13.5 (E13.5), E15.5 and E18.5, and placentas were collected for placenta histopathological analysis and gene expression evaluation at the transcription or translation level. Our results showed that gestational exposure to PM_2.5 significantly reduced the ratio of the mean area of labyrinthine (lab) layer/total area of placentas at E18.5. However, no significant difference was observed at E13.5 and E15.5. Interestingly, genes essential for this process were altered at E13.5 and E18.5 but not E15.5. Furthermore, gestational PM_2.5 exposure decreased the mean area of maternal blood sinuses and fetal blood vessels and suppressed protein expression of CD31 in the PM_2.5 group only at E18.5, while protein expression of CD34 in the PM_2.5 group was similar to that in the control group at all time points. Finally, gestational exposure to PM_2.5 activated mitogen-activated protein kinase (MAPK) pathways at E13.5 and E18.5 but not E15.5. Taking these results together, gestational exposure to PM_2.5 leads to histopathological changes and vascularization injuries of the placenta, and this response may be associated with activation of the MAPK pathway.

Unveiling the role of microRNA-7 in linking TGF-β-Smad-mediated epithelial-mesenchymal transition with negative regulation of trophoblast invasion

Several pregnancy complications result from abnormal trophoblast invasion. The dichotomous effect of TGF-β on epithelial-mesenchymal transition (EMT) between trophoblast invasion and cancer progression remains unknown and a critical concern. We attenuated the expression of TGF-β type 1 receptor (coding by TGFBR1) with RNA interference in trophoblastic cells and significantly enhanced the trophoblastic invasion. Analysis of microRNA profiles in trophoblasts indicated microRNA-7 as a key molecule linking TGF-β with the negative regulation of trophoblast invasion. We then attenuated TGFBR1 and miR-7 transcription by transducing either short hairpin RNA targeting TGFBR1 or anti-miR-7-locked nucleonic acid, and we observed an up-regulation of EMT-related transcription factors (TFs) and their downstream effectors, causing a mesenchymal transition of trophoblasts. Conversely, overexpression of TGFBR1 or miR-7 led to the epithelial transition of trophoblasts. Our results showed that TGF-β-induced miR-7 expression negatively modulated the TGF-β-SMAD family member 2-mediated EMT pathway via targeting EMT-related TFs and down-regulating their mesenchymal markers. These findings possibly explain, at least in part, why TGF-β exerts an opposite effect on EMT during trophoblast invasion and cancer progression.-Shih, J.-C., Lin, H.-H., Hsiao, A.-C., Su, Y.-T., Tsai, S., Chien, C.-L., Kung, H.-N. Unveiling the role of microRNA-7 in linking TGF-β-Smad-mediated epithelial-mesenchymal transition with negative regulation of trophoblast invasion.