Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

Processes influencing the toxicity of microplastics ingested through the diet

The present study assesses the effect of culinary treatment and gastrointestinal digestion upon the release of additives present in microplastics. Organic additives were determined by gas chromatography-mass spectrometry, and inorganic additives using inductively coupled plasma-mass spectrometry. The results revealed a large number of organic additives in the plastic samples, some being classified as possible carcinogens. Contents of Sb in PET (polyethylene terephthalate), Zn and Ba in LDPE (low-density polyethylene) and PVC (polyvinylchloride), and Ti and Pb in LDPE were also noteworthy. The culinary process promotes the release and solubilization of additives into the cooking liquid, with phthalates, benzophenone, N-butylbenzenesulfonamide (NBBS) and bisphenol A being of particular concern. The solubilization of phthalates and NBBS was also observed during gastrointestinal digestion. This study demonstrates that culinary treatment and gastrointestinal digestion promote release and solubilization of additives from plastics ingested with the diet. Such solubilization may facilitate their entry into the systemic circulation.

Microplastics in the soil-water-food nexus: Inclusive insight into global research findings

Nuisance imposed by biotic and abiotic stressors on diverse agroecosystems remains an area of focus for the scientific fraternity. However, emerging contaminants such as microplastics (MP) have imposed additional dimension (alone or in combinations with other stressors) in agroecosystems and keep escalating the challenges to achieve sustainability. MP are recognized as persistent anthropogenic contaminants, fetch global attention due to their unique chemical features that keeps themselves unresponsive to the decaying process. This review has been theorized to assess the current research trends (along with possible gap areas), widespread use of MP, enhancement of the harshness of heavy metals (HMs), complex interactions with physico-chemical constituents of arable soil, accumulation in the edible parts of field crops, dairy products, and other sources to penetrate the food web. So far, the available review articles are oriented to a certain aspect of MP and lack a totality when considered from in soil-water-food perspective. In short, a comprehensive perspective of the adverse effects of MP on human health has been assessed. Moreover, an agro-techno-socio-health prospective-oriented critical assessment of policies and remedial measures linked with MP has provided an extra edge over other similar articles in influential future courses of research.

Human intake assessment of triclosan associated with the daily use of polypropylene-made antimicrobial food packaging

In this work, we aimed to evaluate human intake of triclosan (TCS) associated with real-life use of different brands of Microban™ microwave-safe food packaging. Calculations were based on: TCS migration data (under the worst-case foreseeable conditions), MPs abundance and TCS bioaccessibility from microplastics (MPs), leached from containers under microwave heating. Bioaccessibility studies were performed with in vitro digestion of MPs, followed by liquid-liquid extraction of TCS from digestive fluids and LC-QqQ-MS analysis yielding values of 46 ± 9%. The estimated weekly intake (EWI) of TCS ranged between 11 and 42 μg/kg body weight/week, with migration being the largest contribution (0.6-2.3 mg/week), compared to leaching of MPs (75-300 μg/week). These values represent a significant source of human exposure to TCS, emphasizing the need to harmonize the ban of TCS in food contact materials worldwide and improve compliance testing of food contact articles, particularly those marketed through online sales platforms.

The size-dependence and reversibility of polystyrene nanoplastics-induced hepatic pyroptosis in mice through TXNIP/NLRP3/GSDMD pathway

As emerging environmental contaminants, nanoplastics (NPs) are progressively accumulating in terrestrial and aquatic ecosystems worldwide, posing a potential threat to human health. The liver is considered as one of the primary organs targeted by NPs accumulation in living organisms. However, there remains a large knowledge gap concerning NPs-induced hepatotoxicity. In this study, we examined the impact of chronic exposure to environmentally relevant doses of polystyrene (PS) NPs on hepatic pyroptosis in mice. The results demonstrated that both particle sizes of PS-NPs (100 nm and 500 nm) significantly triggered pyroptosis in the mouse liver, as evidenced by the upregulation of GSDMD-N protein levels; moreover, this pyroptotic effect induced by 100 nm PS-NPs was more pronounced compared to that of 500 nm PS-NPs. Mechanistically, exposure to 100 nm and 500 nm PS-NPs resulted in an upregulation of TXNIP protein expression, thereby activating NLRP3 inflammasome and subsequently inducing inflammatory responses and pyroptosis. Notably, following the termination of PS-NPs exposure and a subsequent recovery period of 50 days, PS-NPs-mediated inflammation and pyroptosis via TXNIP/NLRP3 pathway were effectively ameliorated, even returning to levels close to the baseline. Collectively, our findings provide novel evidence for the size-dependence and reversibility of NPs-induced hepatic pyroptosis through TXNIP/NLRP3/GSDMD pathway in vivo.

Microplastic presence in dog and human testis and its potential association with sperm count and weights of testis and epididymis

The ubiquitous existence of microplastics and nanoplastics raises concerns about their potential impact on the human reproductive system. Limited data exists on microplastics within the human reproductive system and their potential consequences on sperm quality. Our objectives were to quantify and characterize the prevalence and composition of microplastics within both canine and human testes and investigate potential associations with the sperm count, and weights of testis and epididymis. Using advanced sensitive pyrolysis-gas chromatography/mass spectrometry, we quantified 12 types of microplastics within 47 canine and 23 human testes. Data on reproductive organ weights, and sperm count in dogs were collected. Statistical analyses, including descriptive analysis, correlational analysis, and multivariate linear regression analyses were applied to investigate the association of microplastics with reproductive functions. Our study revealed the presence of microplastics in all canine and human testes, with significant inter-individual variability. Mean total microplastic levels were 122.63 µg/g in dogs and 328.44 µg/g in humans. Both humans and canines exhibit relatively similar proportions of the major polymer types, with PE being dominant. Furthermore, a negative correlation between specific polymers such as PVC and PET and the normalized weight of the testis was observed. These findings highlight the pervasive presence of microplastics in the male reproductive system in both canine and human testes, with potential consequences on male fertility.

Enhanced hepatic metabolic perturbation of polystyrene nanoplastics by UV irradiation-induced hydroxyl radical generation

The environmental behavior of and risks associated with nanoplastics (NPs) have attracted considerable attention. However, compared to pristine NPs, environmental factors such as ultraviolet (UV) irradiation that lead to changes in the toxicity of NPs have rarely been studied. We evaluated the changes in morphology and physicochemical properties of polystyrene (PS) NPs before and after UV irradiation, and compared their hepatotoxicity in mice. The results showed that UV irradiation caused particle size reduction and increased the carbonyl index (CI) and negative charge on the particle surface. UV-aged PS NPs (aPS NPs) could induce the generation of hydroxyl radicals (·OH), but also further promoted the generation of ·OH in the Fenton reaction system. Hepatic pathological damage was more severe in mice exposed to aPS NPs, accompanied by a large number of vacuoles and hepatocyte balloon-like changes and more marked perturbations in blood glucose and serum lipoprotein, alanine aminotransferase and aspartate aminotransferase levels. In addition, exposure to PS NPs and aPS NPs, especially aPS NPs, triggered oxidative stress and significantly damaged the antioxidant capacity of mice liver. Compared with PS NPs, exposure to aPS NPs increased the number of altered metabolites in hepatic and corresponding metabolic pathways, especially glutathione metabolism. Our research suggests that UV irradiation can disrupt the redox balance in organisms by promoting the production of ·OH, enhancing PS NPs-induced liver damage and metabolic disorders. This study will help us understand the health risks of NPs and to avoid underestimation of the risks of NPs in nature.

Analysis of Biodistribution and in vivo Toxicity of Varying Sized Polystyrene Micro and Nanoplastics in Mice

Introduction

Studies have shown that microplastics (MPs) and nanoplastics (NPs) could accumulate in the human body and pose a potential threat to human health. The purpose of this study is to evaluate the biodistribution and toxicity of MPs/NPs with different particle sizes comprehensively and thoroughly.

Methods

The purpose of this study was to investigate the biodistribution and in vivo toxicity of polystyrene (PS) MPs/NPs with different sizes (50 nm, 100 nm, and 500 nm). The BALB/c mice were given 100 μL of PS50, PS100 and PS500 at the dosage of 1 mg/kg BW or 10 mg/kg BW, respectively, by gavage once a day. After 28 consecutive days of treatment, the biodistribution of differently sized PS MPs/NPs was determined through cryosection fluorescence microscopy and fluorescent microplate reader analysis, and the subsequent effects of differently sized PS MPs/NPs on histopathology, hematology and blood biochemistry were also evaluated.

Results

The results showed that the three different sizes of PS MPs/NPs were distributed in the organs of mice, mainly in the liver, spleen, and intestine. At the same time, the smaller the particle size, the more they accumulate in the body and more easily penetrate the tissue. During the whole observation period, no abnormal behavior and weight change were observed. The results of H&E staining showed that no severe histopathological abnormalities were observed in the main organs in the low-dose exposure group, while. Exposure of three sizes of PS MPs/NPs could cause some changes in hematological parameters or biochemical parameters related to heart, liver, and kidney function; meanwhile, there were size- and dose-dependencies.

Conclusion

The biological distribution and toxicity of plastic particles in mice were more obvious with the decrease of particle size and the increase of concentration of plastic particles. Compared with MPs, NPs were easier to enter the tissues and produce changes in liver, kidney, and heart functions. Therefore, more attention should be paid to the toxicity of NPs.

Unveiling the ecotoxicological impact of microplastics on organisms - the persistent organic pollutant (POP): A comprehensive review

Microplastics have been ubiquitous in our environment for decades, and numerous studies have revealed their extensive dispersion, reaching far beyond the surface of the land, soil, aquatic ecosystems. They have infiltrated the food-chain, the food web, even the air we breathe, as well as the water we drink. Microplastics have been detected in the food we consume, acting as vectors for hazardous chemicals that adhere to their hydrophobic surfaces. This can result in the transfer of these chemicals to the aquatic life, posing a threat to their well-being. The release of microplastics into different environmental settings can give rise to various eco-toxicological implications. The substantial body of literature has led scientists to the consensus that microplastic pollution is a global problem with the potential to impact virtually any type of ecosystem. This paper aims to discuss crucial information regarding the occurrence, accumulation, and ecological effects of microplastics on organisms. It also highlights the new and emerging disease named "Plasticosis" that is directly linked to microplastics and its toxicological effects like permanent scarring and long-term inflammation in the digestive system of the seabirds. By comprehending the behaviour of these microplastic pollutants in diverse habitats and evaluating their ecological consequences, it becomes possible to facilitate a better understanding of this toxicological issue.

Disposition of [14C]-polystyrene microplastics after oral administration to lactating sheep

Microplastics have become a ubiquitous contaminant, but their fate in food animals is largely unknown. In this study, [14C]-polystyrene microplastic (PS-MP) particles were orally dosed to lactating sheep to evaluate their absorption and disposition. Elimination of the [14C]-PS-MP was predominately through faeces with faecal radioactivity peaking at 24 h post-dosing but continuing to be present throughout the entire 72 h study period. Only a small fraction (≤ 1%) of the dosed [14C]-PS-MP was present in blood, milk, and urine. Pharmacokinetic analysis of blood plasma radioactivity, using non-compartment modeling, indicated rapid absorption (T1/2 0.4 to 3 h) with slow elimination (T1/2 37 to 48 h). Radioactivity in milk and urine had similar elimination patterns with radiocarbon activities peaking 24 h post-dosing with detectable elimination throughout the 72 h study period. No radioactivity was quantifiable in tissues at the 72 h withdrawal period.

Microplastics - A Growing Concern as Carcinogens in Cancer Etiology: Emphasis on Biochemical and Molecular Mechanisms

In today's world, the widespread presence of microplastics is undeniable, with concentrations found in various environments, including up to 1000 particles per liter in seawater and up to 10 particles per cubic meter in the atmosphere. Originating from diverse sources, both intentional and unintentional, these minuscule fragments, measuring less than 5 mm, pose significant threats to environmental and human health. Recent research has uncovered a concerning link between microplastics and cancer, prompting urgent investigation. Studies demonstrate microplastics can infiltrate cells, disrupt biological processes, and potentially foster carcinogenic environments. From inducing DNA damage and oxidative stress to triggering inflammatory responses and dysregulating cellular pathways, microplastics exhibit a multifaceted capability in contributing to cancer development. Furthermore, microplastics act as carriers for a range of contaminants, compounding their impact on human health. Their accumulation within tissues and organs raises concerns for short and long-term health consequences, including chronic diseases, reproductive issues, and developmental abnormalities. This review explores the biochemical and molecular mechanisms underlying the interaction between microplastics and cellular systems, providing insights into routes of exposure and health effects, with a focus on lung, skin, and digestive system cancers. As we confront this pressing environmental and public health challenge, a deeper understanding of the microplastic-cancer relationship is crucial to safeguarding the well-being of present and future generations.

Advancing Evaluation of Microplastics Thresholds to Inform Water Treatment Needs and Risks

Although human health impacts of microplastics are not well understood, concern regarding chemical contaminants retained on or within them is growing. Drinking water providers are increasingly asked about these risks, but strategies for evaluating them and the extent of treatment needed to manage them are currently lacking. Microplastics can potentially induce health effects if the concentration of contaminants adsorbed to them exceeds predetermined drinking water guidelines (e.g., Maximum Contaminant Levels). The risk posed by microplastics due to adsorbed contaminants is difficult to determine, but a worst-case scenario can be evaluated by using adsorption capacity. Here, a "Threshold Microplastics Concentration" (TMC) framework is developed to evaluate whether waterborne microplastic concentrations can potentially result in the intake of regulated contaminants on/in microplastics at levels of human health concern and identify treatment targets for managing associated health risk. Exceeding the TMC does not indicate an immediate health risk; it informs the need for detailed risk assessment or further treatment evaluation to ensure particle removal targets are achieved. Thus, the TMC concept and framework provide an updateable, science-based screening tool to determine if there is a need for detailed risk assessment or treatment modification due to waterborne microplastics in supplies used for potable water production.

Polystyrene nanoplastics of different particle sizes regulate the polarization of pro-inflammatory macrophages

Microplastics (MPs) are defined as plastic particles smaller than 5 mm in size, and nanoplastics (NPs) are those MPs with a particle size of less than 1000 nm or 100 nm. The prevalence of MPs in the environment and human tissues has raised concerns about their potential negative effects on human health. Macrophages are the major defence against foreign substances in the intestine, and can be polarized into two types: the M1 phenotype and the M2 phenotype. However, the effect of NPs on the polarization of macrophages remains unclear. Herein, we selected polystyrene, one of the most plastics in the environment and controlled the particle sizes at 50 nm and 500 nm respectively to study the effects on the polarization of macrophages. We used mouse RAW264.7 cell line models in this macrophage-associated study. Experiments on cell absorption showed that macrophages could quickly ingest polystyrene nanoplastics of both diameters with time-dependent uptake. Compared to the untreated group and 10 μg/mL treatment group, macrophages exposed to 50 μg/mL groups (50 nm and 500 nm) had considerably higher levels of CD86, iNOS, and TNF-α, but decreased levels of aCD206, IL-10, and Arg-1. According to these findings, macrophage M1 and M2 polarization can both be induced and inhibited by 50 μg/mL 50 nm and 500 nm polystyrene nanoplastics. This work provided the first evidence of a possible MPs mode of action with appropriate concentration and size through the production of polarized M1, providing dietary and environmental recommendations for people, particularly those with autoimmune and autoinflammatory illnesses.

Oral Exposure to Microplastics Affects the Neurochemical Plasticity of Reactive Neurons in the Porcine Jejunum

Plastics are present in almost every aspect of our lives. Polyethylene terephthalate (PET) is commonly used in the food industry. Microparticles can contaminate food and drinks, posing a threat to consumers. The presented study aims to determine the effect of microparticles of PET on the population of neurons positive for selected neurotransmitters in the enteric nervous system of the jejunum and histological structure. An amount of 15 pigs were divided into three groups (control, receiving 0.1 g, and 1 g/day/animal orally). After 28 days, fragments of the jejunum were collected for immunofluorescence and histological examination. The obtained results show that histological changes (injury of the apical parts of the villi, accumulations of cellular debris and mucus, eosinophil infiltration, and hyperaemia) were more pronounced in pigs receiving a higher dose of microparticles. The effect on neuronal nitric oxide synthase-, and substance P-positive neurons, depends on the examined plexus and the dose of microparticles. An increase in the percentage of galanin-positive neurons and a decrease in cocaine and amphetamine-regulated transcript-, vesicular acetylcholine transporter-, and vasoactive intestinal peptide-positive neurons do not show such relationships. The present study shows that microparticles can potentially have neurotoxic and pro-inflammatory effects, but there is a need for further research to determine the mechanism of this process and possible further effects.

The Effect of Rapeseed Oil Biopolyols and Cellulose Biofillers on Selected Properties of Viscoelastic Polyurethane Foams

This paper presents the results of research on polyurethane viscoelastic foams (PUVFs) modified with biomaterials. This investigation looked at the effect of the biomaterials on the foaming processes, as well as the acoustical and selected physical-mechanical properties of the foams. Various types of rapeseed oil biopolyols and microcellulose were used to modify the materials. The analysis of properties covered a reference biopolyol-free sample and materials containing 10 wt.%, 20 wt.%, and 30 wt.% of different types of biopolyols in the mixture of polyol components. The biopolyols differed in terms of functionality and hydroxyl value (OHv). Next, a selected formulation was modified with various microcellulose biofillers in the amount of 0.5-2 wt.%. The PUVFs, with apparent densities of more than 210 kg/m3 and open-cell structures (more than 85% of open cells), showed a slow recovery to their original shape after deformation when the pressure force was removed. They were also characterized by a tensile strength in the range of 156-264 kPa, elongation at break of 310-510%, hardness of 8.1-23.1 kPa, and a high comfort factor of 3.1-7.1. The introduction of biopolyols into the polyurethane system resulted in changes in sound intensity levels of up to 31.45%, while the addition of fillers resulted in changes in sound intensity levels of up to 13.81%.

Primary Microplastics in the Ecosystem: Ecological Effects, Risks, and Comprehensive Perspectives on Toxicology and Detection Methods

Recent discoveries of microplastics in cities, suburbs, and even remote locations, far from microplastic source regions, have raised the possibility of long-distance transmission of microplastics in many ecosystems. A little is known scientifically about the threat that it posed to the environment by microplastics. The problem's apparent size necessitates the rapid development of reliable scientific advice regarding the ecological risks of microplastics. These concerns are brought on by the lack of consistent sample and identification techniques, as well as the limited physical analysis and understanding of microplastic pollution. This review provides insight regarding some unaddressed issues about the occurrence, fate, movement, and impact of microplastics, in general, with special emphasis on primary microplastics. The approaches taken in the earlier investigations have been analyzed and different recommendations for future research have been suggested.

Investigation of the effects of nanoplastic polyethylene terephthalate on environmental toxicology using model Drosophila melanogaster

Plastic pollution has become a major environmental concern, and various plastic polymers are used daily. A study was conducted to examine the toxic effects of polyethylene terephthalate (PET) nanoplastics (NPLs) on Drosophila melanogaster. We have successfully synthesized PET NPLs and characterized using DLS, Zeta potential, TEM, HRTEM, SAED, XRD, FTIR, and Raman spectroscopy to gain crucial insights into the structure and properties. We fed PET NPLs to Drosophila to assess toxicity. ROS was quantified using DCFH-DA and NBT, and the nuclear degradation was checked by DAPI staining. Quantification of protein and activity of antioxidant enzymes like SOD, catalase depicted the adverse consequences of PET NPLs exposure. The dorsal side of the abdomens, eyes, and wings were also defective when phenotypically analyzed. These results substantiate the genotoxic and cytotoxic impact of nanoplastics. Notably, behavioral observations encompassing larval crawling and climbing of adults exhibit normal patterns, excluding the presence of neurotoxicity. Adult Drosophila showed decreased survivability, and fat accumulation enhanced body weight. These findings contribute to unraveling the intricate mechanisms underlying nanoplastic toxicity and emphasize its potential repercussions for organismal health and ecological equilibrium.

The effect of environmental health education on microplastic pollution awareness

OBJECTIVE

The aim of this research is to investigate the effect of environmental health education given at the ninth-grade level on the microplastic pollution awareness level of students.

METHODS

This pretest-posttest experimental study with a randomized control group was conducted between 2022 and 2023 in three high schools in a province in eastern Turkey. The sample of the study consisted of 90 ninth-grade students (experimental group: 45, control group: 45), and the sample magnitude was determined by power analysis. Tools such as the "Personal Information Form" and "Microplastic Pollution Awareness Scale (MPAS)" were used to collect data. Training was given to the experimental group as a nursing intervention in a total of four sessions at 15-day intervals. No intervention was applied to the individuals in the control group.

RESULTS

While no significant difference was observed in the MPAS total score in the control group according to the pretest and posttest mean scores, a significant difference was observed in the MPAS total score in the experimental group (p < 0.05). When the posttest mean scores of the experimental and control groups were examined, it was observed that the posttest mean scores of the experimental group were higher than the posttest mean scores of the control group and there was a statistically significant difference (p < 0.05).

CONCLUSION

It was observed that the microplastic pollution awareness level of the experimental group students who received environmental health training increased significantly. The issue of environmental health should be integrated into the education curriculum in schools and students' awareness levels should be increased.

Beyond surface: Unveiling ecological and economic ramifications of microplastic pollution in the oceans

Every year, the global production of plastic waste reaches a staggering 400 million metric tons (Mt), precipitating adverse consequences for the environment, food safety, and biodiversity as it degrades into microplastics (MPs). The multifaceted nature of MP pollution, coupled with its intricate physiological impacts, underscores the pressing need for comprehensive policies and legislative frameworks. Such measures, alongside advancements in technology, hold promise in averting ecological catastrophe in the oceans. Mandated legislation represents a pivotal step towards restoring oceanic health and securing the well-being of the planet. This work offers an overview of the policy hurdles, legislative initiatives, and prospective strategies for addressing global pollution due to MP. Additionally, this work explores innovative approaches that yield fresh insights into combating plastic pollution across various sectors. Emphasizing the importance of a global plastics treaty, the article underscores its potential to galvanize collaborative efforts in mitigating MP pollution's deleterious effects on marine ecosystems. Successful implementation of such a treaty could revolutionize the plastics economy, steering it towards a circular, less polluting model operating within planetary boundaries. Failure to act decisively risks exacerbating the scourge of MP pollution and its attendant repercussions on both humanity and the environment. Central to this endeavor are the formulation, content, and execution of the treaty itself, which demand careful consideration. While recognizing that a global plastics treaty is not a panacea, it serves as a mechanism for enhancing plastics governance and elevating global ambitions towards achieving zero plastic pollution by 2040. Adopting a life cycle approach to plastic management allows for a nuanced understanding of possible trade-offs between environmental impact and economic growth, guiding the selection of optimal solutions with socio-economic implications in mind. By embracing a comprehensive strategy that integrates legislative measures and technological innovations, we can substantially reduce the influx of marine plastic litter at its sources, safeguarding the oceans for future generations.

Microplastics and Anthropogenic Particles in Recreationally Caught Freshwater Fish from an Urbanized Region of the North American Great Lakes

BACKGROUND

Microplastics are a pervasive contaminant cycling through food webs-leading to concerns regarding exposure and risk to humans.

OBJECTIVES

We aimed to quantify and characterize anthropogenic particle contamination (including microplastics) in fish caught for human consumption from the Humber Bay region of Lake Ontario. We related quantities of anthropogenic particles to other factors (e.g., fish size) that may help in understanding accumulation of microplastics in fish.

METHODS

A total of 45 samples of six fish species collected from Humber Bay in Lake Ontario near Toronto, Ontario, Canada, were examined for anthropogenic particles in their gastrointestinal (GI) tracts and fillets. Using microscopy and spectroscopy, suspected anthropogenic particles were identified and characterized.

RESULTS

We observed anthropogenic particles in the GI tracts and fillets of all species. Individual fish had a mean ± standard deviation of 138 ± 231 anthropogenic particles, with a single fish containing up to 1,508 particles. GI tracts had 93 ± 226 particles/fish (9.8 ± 32.6 particles/gram), and fillets had 56 ± 61 particles/fish (0.5 ± 0.8 particles/gram). Based on a consumption rate of 2 servings/week, the average yearly human exposure through the consumption of these fish fillets would be 12,800 ± 18,300 particles.

DISCUSSION

Our findings suggest that consumption of recreationally caught freshwater fish can be a pathway for human exposure to microplastics. The elevated number of particles observed in fish from Humber Bay highlights the need for large-scale geographic monitoring, especially near sources of microplastics. Currently, it is unclear what the effects of ingesting microplastics are for humans, but given that recreationally caught freshwater fish are one pathway for human exposure, these data can be incorporated into future human health risk assessment frameworks for microplastics. https://doi.org/10.1289/EHP13540.

Multi-level toxicity assessment of polylactic acid (PLA) microplastics on the cladoceran Daphnia magna

The accumulation of plastics waste in the environment has raised a worrisome concern, moving the society to seek out for sustainable solutions, such as the transition from the use of fossil-based, conventional plastics to bioplastics (BPs). However, once in the environment bioplastics have the same probability to accumulate and experience weathering processes than conventional plastics, leading to the formation of microplastics (MPs). However, to date the information on the potential toxicity of MPs originated from the weathering of bioplastics is limited. Thus, this study aimed at investigating the adverse effects induced by the exposure to MPs made of a bioplastic polymer, the polylactic acid (PLA), towards the freshwater cladoceran Daphnia magna. Organisms were exposed for 21 days to three concentrations (0.125 µg/mL, 1.25 µg/mL and 12.5 µg/mL) of PLA microplastics (hereafter PLA-MPs). A multi-level approach was performed to investigate the potential effects through the biological hierarchy, starting from the sub-individual up to the individual level. At the sub-individual level, changes in the oxidative status (i.e., the amount of reactive oxygen species and the activity of antioxidant and detoxifying enzymes) and oxidative damage (i.e., lipid peroxidation) were explored. Moreover, the total caloric content as well as the content of protein, carbohydrate and lipid content assess were used to investigate the effects on energy reserves. At individual level the changes in swimming activity (i.e., distance moved and swimming speed) were assessed. Our results showed that the exposure to PLA-MPs induced a slight modulation in the oxidative status and energy reserves, leading to an increase in swimming behavior of treated individuals compared to control conspecifics. These results suggest that the exposure to MPs made of a bioplastic polymer can induce adverse effects similar to those caused by conventional polymers.

Mapping Microplastics in Humans: Analysis of Polymer Types, and Shapes in Food and Drinking Water-A Systematic Review

Microplastics (MPs) pervade the environment, infiltrating food sources and human bodies, raising concerns about their impact on human health. This review is focused on three key questions: (i) What type of polymers are humans most exposed to? (ii) What are the prevalent shapes of MPs found in food and human samples? (iii) Are the data influenced by the detection limit on the size of particles? Through a systematic literature analysis, we have explored data on polymer types and shapes found in food and human samples. The data provide evidence that polyester is the most commonly detected polymer in humans, followed by polyamide, polyurethane, polypropylene, and polyacrylate. Fibres emerge as the predominant shape across all categories, suggesting potential environmental contamination from the textile industry. Studies in humans and drinking water reported data on small particles, in contrast to larger size MPs detected in environmental research, in particular seafood. Discrepancies in size detection methodologies across different reports were identified, which could impact some of the discussed trends. This study highlights the need for more comprehensive research on the interactions between MPs and biological systems and the effects of MPs on toxicity, together with standardised analytical methodologies to accurately assess contamination levels and human exposure. Understanding these dynamics is essential for formulating effective strategies to mitigate the environmental and health implications of MP pollution.

Features, Potential Invasion Pathways, and Reproductive Health Risks of Microplastics Detected in Human Uterus

Microplastics (MPs) are ubiquitous in global ecosystems and may pose a potential risk to human health. However, critical information on MP exposure and risk to female reproductive health is still lacking. In this study, we characterized MPs in human endometrium and investigated their size-dependent entry mode as well as potential reproductive toxicity. Endometrial tissues of 22 female patients were examined, revealing that human endometrium was contaminated with MPs, mainly polyamide (PA), polyurethane (PU), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyethylene (PE), ranging from 2-200 μm in size. Experiments conducted in mice demonstrated that the invasion of the uterus by MPs was modulated either through diet-blood circulation (micrometer-sized particles) or via the vagina-uterine lacuna mode (larger particles reaching a size of 100 μm. Intravenous exposure to MPs resulted in reduced fertility and abnormal sex ratio in mouse offspring (P < 0.05). After 3.5 months of intragastric exposure, there was a significant inflammatory response in the endometrium (P < 0.05), confirmed by embryo transfer as a uterine factor leading to decreased fertility. Furthermore, human endometrial organoids cultured with MPs in vitro exhibited significantly apoptotic responses and disrupted growth patterns (P < 0.01). These findings raise significant concerns regarding MP contamination in the human uterus and its potential effects on reproductive health.

Probiotics an emerging therapeutic approach towards gut-brain-axis oriented chronic health issues induced by microplastics: A comprehensive review

Applications for plastic polymers can be found all around the world, often discarded without any prior care, exacerbating the environmental issue. When large waste materials are released into the environment, they undergo physical, biological, and photo-degradation processes that break them down into smaller polymer fragments known as microplastics (MPs). The time it takes for residual plastic to degrade depends on the type of polymer and environmental factors, with some taking as long as 600 years or more. Due to their small size, microplastics can contaminate food and enter the human body through food chains and webs, causing gastrointestinal (GI) tract pain that can range from local to systemic. Microplastics can also acquire hydrophobic organic pollutants and heavy metals on their surface, due to their large surface area and surface hydrophobicity. The levels of contamination on the microplastic surface are significantly higher than in the natural environment. The gut-brain axis (GB axis), through which organisms interact with their environment, regulate nutritional digestion and absorption, intestinal motility and secretion, complex polysaccharide breakdown, and maintain intestinal integrity, can be altered by microplastics acting alone or in combination with pollutants. Probiotics have shown significant therapeutic potential in managing various illnesses mediated by the gut-brain axis. They connect hormonal and biochemical pathways to promote gut and brain health, making them a promising therapy option for a variety of GB axis-mediated illnesses. Additionally, taking probiotics with or without food can reduce the production of pro-inflammatory cytokines, reactive oxygen species (ROS), neuro-inflammation, neurodegeneration, protein folding, and both motor and non-motor symptoms in individuals with Parkinson's disease. This study provides new insight into microplastic-induced gut dysbiosis, its associated health risks, and the benefits of using both traditional and next-generation probiotics to maintain gut homeostasis.

Accounting on silk for reducing microplastic pollution from textile sector: a viewpoint

Microplastic pollution is the emerging issue in the recent past and has been identified in the remotely located ecosystems. The textile sector is one of the key contributors in the microplastic pollution. Keeping this in view, the present viewpoint has been planned to address the systematic possible reduction of microplastic pollution. It has been observed through the literature that silk is having a promising material to reduce the microplastic problems and its associated environmental risk due to its non-persistent nature.

Microplastics exposure altered hematological and lipid profiles as well as liver and kidney function parameters in albino rats (Rattus norvegicus)

The global occurrence of microplastics and their poorly understood health implications underscore the need for scientific investigation. This study aimed to assess the effects of microplastics exposure. Twenty-five (25) albino rats (Rattus norvegicus) were divided into five (5) groups, each consisting of five rats. Group 1 (the negative control) received normal feed; group 2 (the positive control) was administered a 10 % lead acetate solution; and groups 3, 4, and 5 were administered 1 %, 5 %, and 10 % microplastic solutions, respectively. The rats were monitored for 28 days, after which blood samples were taken for hematological and lipid profiles as well as liver and kidney function parameters. The results revealed dose-dependent significant (p < 0.05) alterations in the health indices of the treated rats and the positive control compared with the negative control. Specifically, the hematological parameters, including the white blood cells (WBC) and its subtypes, were reduced, indicating immunosuppressive effects, and the red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), platelets, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were reduced, indicating anemia. The 1 % and 5 % microplastic solutions raised the lipid profiles of the treated rats, including total cholesterol (TC), triglycerides (TG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL), while the 10 % concentration decreased them, causing hyperlipidemia and hypolipidemia, respectively. The liver function parameters, including total protein (TP), albumin (ALB), aspartate transaminase (AST), alanine transaminase (ALT), and alkaline phosphatase (ALP), were elevated, indicating liver damage. Elevation of kidney function parameters, including sodium ion (Na+), potassium ion (K+), chloride ion (Cl-), urea, and creatinine (CRT), were noticed, suggesting kidney injuries. It can be inferred from these results that microplastics are toxic. Hence, human exposure to microplastics should be reduced to a minimum.

Polystyrene microplastic-induced endoplasmic reticulum stress contributes to growth plate endochondral ossification disorder in young rat

BACKGROUND

Previous studies on the effects of microplastics (MPs) on bone in early development are limited. This study aimed to investigate the adverse effects of MPs on bone in young rats and the potential mechanism.

METHODS

Three-week-old female rats were orally administered MPs for 28 days, and endoplasmic reticulum (ER) stress inhibitor salubrinal (SAL) and ER stress agonist tunicamycin (TM) were added to evaluate the effect of ER stress on toxicity of MPs. The indicators of growth and plasma markers of bone turnover were evaluated. Tibias were analyzed using micro-computed tomography (micro-CT). Histomorphological staining of growth plates was performed, and related gene expression of growth plate chondrocytes was tested.

RESULTS

After exposure of MPs, the rats had decreased growth, shortened tibial length, and altered blood calcium and phosphorus metabolism. Trabecular bone was sparse according to micro-CT inspection. In the growth plate, the thickness of proliferative zone substantial reduced while the thickness of hypertrophic zone increased significantly, and the chondrocytes were scarce and irregularly arranged according to tibial histological staining. The transcription of the ER stress-related genes BIP, PERK, ATF4, and CHOP dramatically increased, and the transcription factors involved in chondrocyte proliferation, differentiation, apoptosis, and matrix secretion were aberrant according to RT-qPCR and western blotting. Moreover, the addition of TM showed higher percentage of chondrocyte death. Administration of SAL alleviated all of the MPs-induced symptoms.

CONCLUSION

These results indicated that MPs could induce growth retardation and longitudinal bone damage in early development. The toxicity of MPs may attribute to induced ER stress and impaired essential processes of the endochondral ossification after MPs exposure.

Understanding microplastic pollution of marine ecosystem: a review

Microplastics are emerging as prominent pollutants across the globe. Oceans are becoming major sinks for these pollutants, and their presence is widespread in coastal regions, oceanic surface waters, water column, and sediments. Studies have revealed that microplastics cause serious threats to the marine ecosystem as well as human beings. In the past few years, many research efforts have focused on studying different aspects relating to microplastic pollution of the oceans. This review summarizes sources, migration routes, and ill effects of marine microplastic pollution along with various conventional as well as advanced methods for microplastics analysis and control. However, various knowledge gaps in detection and analysis require attention in order to understand the sources and transport of microplastics, which is critical to deploying mitigation strategies at appropriate locations. Advanced removal methods and an integrated approach are necessary, including government policies and stringent regulations to control the release of plastics.

Microplastics contamination in water supply system and treatment processes

Due to global demand, millions of tons of plastics have been widely consumed, resulting in the widespread entry of vast amounts of microplastic particles into the environment. The presence of microplastics (MPs) in water supplies, including bottled water, has undergone systematic review, assessing the potential impacts of MPs on humans through exposure assessment. The main challenges associated with current technologies lie in their ability to effectively treat and completely remove MPs from drinking and supply water. While the risks posed by MPs upon entering the human body have not yet been fully revealed, there is a predicted certainty of negative impacts. This review encompasses a range of current technologies, spanning from basic to advanced treatments and varying in scale. However, given the frequent detection of MPs in drinking and bottled water, it becomes imperative to implement comprehensive management strategies to address this issue effectively. Consequently, integrating current technologies with management options such as life-cycle assessment, circular economy principles, and machine learning is crucial to eliminating this pervasive problem.

Inhibitory Impact of Prenatal Exposure to Nano-Polystyrene Particles on the MAP2K6/p38 MAPK Axis Inducing Embryonic Developmental Abnormalities in Mice

Nanoplastics, created by the fragmentation of larger plastic debris, are a serious pollutant posing substantial environmental and health risks. Here, we developed a polystyrene nanoparticle (PS-NP) exposure model during mice pregnancy to explore their effects on embryonic development. We found that exposure to 30 nm PS-NPs during pregnancy resulted in reduced mice placental weight and abnormal embryonic development. Subsequently, our transcriptomic dissection unveiled differential expression in 102 genes under PS-NP exposure and the p38 MAPK pathway emerged as being significantly altered in KEGG pathway mapping. Our findings also included a reduction in the thickness of the trophoblastic layer in the placenta, diminished cell invasion capabilities, and an over-abundance of immature red cells in the blood vessels of the mice. In addition, we validated our findings through the human trophoblastic cell line, HTR-8/SVneo (HTR). PS-NPs induced a drop in the vitality and migration capacities of HTR cells and suppressed the p38 MAPK signaling pathway. This research highlights the embryotoxic effects of nanoplastics on mice, while the verification results from the HTR cells suggest that there could also be certain impacts on the human trophoblast layer, indicating a need for further exploration in this area.

The first reported values of microplastics in prostate

BACKGROUND

Microplastics are ubiquitous, widespread environmental pollutants with unavoidable human exposure. Herein, it was aimed to investigate the presence of microplastics in prostate tissue.

METHODS

Prostate tissues from 12 patients who underwent Trans Urethral Resection of the Prostate (TUR-P) were analyzed to investigate the presence of microplastics. Initially, the prostate tissues were analyzed for microplastic particles using a light microscope after extraction. Subsequently, the chemical composition of the particles found in the prostate tissues was characterized using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectrophotometry.

RESULTS

Microplastic particles of various types were detected in 6 out of 12 patients. All detected plastic particles in this study were microplastics, with sizes below 26 μm in size. These microplastics exhibited different shapes as pellets, spheres or fibers. Overall, among the 12 analyzed prostate tissue samples, four different types of plastic were identified in six samples. The most common type of microplastic detected was Polyamide (Nylon 6), found in samples from three patients. Other detected types, Polypropylene, Polyacrylic Acid and Poly (dimethylsiloxane) were each determined in samples from one patient.

CONCLUSIONS

This is the first study to demonstrate the presence of microplastics in prostate tissue, serving as an exploratory investigation, which can trigger further research to validate the results in a larger patient cohort.

Exposure to polystyrene microplastics and perfluorooctane sulfonate disrupt the homeostasis of intact planarians and the growth of regenerating planarians

Microplastics (MPs) and perfluorinated compounds (PFAS) are widespread in the global ecosystem. MPs have the ability to adsorb organic contaminants such as perfluorooctane sulfonate (PFOS), leading to combined effects. The current work aims to explore the individual and combined toxicological effects of polystyrene (PS) and PFOS on the growth and nerves of the freshwater planarian (Dugesia japonica). The results showed that PS particles could adsorb PFOS. PS and PFOS impeded the regeneration of decapitated planarians eyespots, whereas the combined treatment increased the locomotor speed of intact planarians. PS and PFOS caused significant DNA damage, while co-treatment with different PS concentrations aggravated and attenuated DNA damage, respectively. Further studies at the molecular level have shown that PS and PFOS affect the proliferation and differentiation of neoblasts in both intact and regenerating planarians, alter the expression levels of neuronal genes, and impede the development of the nervous system. PS and PFOS not only disrupted the homeostasis of intact planarians, but also inhibited the regeneration of decapitated planarians. This study is the first to assess the multiple toxicity of PS and PFOS to planarians after combined exposure. It provides a basis for the environmental and human health risks of MPs and PFAS.

The triple exposure nexus of microplastic particles, plastic-associated chemicals, and environmental pollutants from a human health perspective

The presence of microplastics (MPs) is increasing at a dramatic rate globally, posing risks for exposure and subsequent potential adverse effects on human health. Apart from being physical objects, MP particles contain thousands of plastic-associated chemicals (i.e., monomers, chemical additives, and non-intentionally added substances) captured within the polymer matrix. These chemicals are often migrating from MPs and can be found in various environmental matrices and human food chains; increasing the risks for exposure and health effects. In addition to the physical and chemical attributes of MPs, plastic surfaces effectively bind exogenous chemicals, including environmental pollutants (e.g., heavy metals, persistent organic pollutants). Therefore, MPs can act as vectors of environmental pollution across air, drinking water, and food, further amplifying health risks posed by MP exposure. Critically, fragmentation of plastics in the environment increases the risk for interactions with cells, increases the presence of available surfaces to leach plastic-associated chemicals, and adsorb and transfer environmental pollutants. Hence, this review proposes the so-called triple exposure nexus approach to comprehensively map existing knowledge on interconnected health effects of MP particles, plastic-associated chemicals, and environmental pollutants. Based on the available data, there is a large knowledge gap in regard to the interactions and cumulative health effects of the triple exposure nexus. Each component of the triple nexus is known to induce genotoxicity, inflammation, and endocrine disruption, but knowledge about long-term and inter-individual health effects is lacking. Furthermore, MPs are not readily excreted from organisms after ingestion and they have been found accumulated in human blood, cardiac tissue, placenta, etc. Even though the number of studies on MPs-associated health impacts is increasing rapidly, this review underscores that there is a pressing necessity to achieve an integrated assessment of MPs' effects on human health in order to address existing and future knowledge gaps.

The cardiovascular toxicity of polystyrene microplastics in rats: based on untargeted metabolomics analysis

Background

Polystyrene microplastics (PS-MPs) exhibit multi-target, multi-dimensional, chronic, and low toxicity to the cardiovascular system. They enter the bloodstream through the gastrointestinal tract and respiratory system, altering blood parameters and conditions, inducing thrombotic diseases, and damaging myocardial tissue through the promotion of oxidative stress and inflammatory responses in myocardial cells. However, many of the links and mechanisms remain unclear.

Methods

In this study, 48 wistar rats were randomly divided into four groups and exposed to different concentrations of PS-MPs: control group (0 mg/kg/d), low dose group (0.5 mg/kg/d), middle dose group (5 mg/kg/d) and high dose group (50 mg/kg/d), with 12 rats in each group. After 90 consecutive days of intragastric administration of PS-MPs, biochemical markers in myocardium, aorta and blood were detected, and HE staining was performed to observe the toxic effects of PS-mps on cardiovascular system. Furthermore, non-targeted metabolomics methods were used to analyze the effect of PS-MPs exposure on the metabolism of cardiovascular system in rats, and to explore its potential molecular mechanism.

Results

The results revealed no pathological changes in the heart and aorta following PS-MPs exposure. However, the myocardial enzyme levels in the high dose PS-MPs group of rats showed a significant increase. Moreover, exposure to polystyrene microplastics caused a disorder in lipid metabolism in rats, and led to an increase in indicators of inflammation and oxidative stress in myocardial and aortic tissues, but resulted in a decrease in the level of IL-6. Untargeted metabolomics results showed that metabolites with antioxidant and anti-inflammatory effects, including equol and 4-hydroxybenzoic acid, were significantly upregulated.

Conclusion

These results suggest that long-term exposure to high concentrations of PS-MPs may lead to abnormal lipid metabolism and cardiovascular system damage. The mechanism may be related to oxidative stress and inflammatory response. Exogenous antioxidants and changes in own metabolites may have a protective effect on the injury. Therefore, understanding the toxicological mechanism of PS-MPs not only helps to elucidate its pathogenesis, but also provides new ideas for the treatment of chronic diseases.

Exposure to Environmental Toxins: Potential Implications for Stroke Risk via the Gut- and Lung-Brain Axis

Recent evidence indicates that exposure to environmental toxins, both short-term and long-term, can increase the risk of developing neurological disorders, including neurodegenerative diseases (i.e., Alzheimer's disease and other dementias) and acute brain injury (i.e., stroke). For stroke, the latest systematic analysis revealed that exposure to ambient particulate matter is the second most frequent stroke risk after high blood pressure. However, preclinical and clinical stroke investigations on the deleterious consequences of environmental pollutants are scarce. This review examines recent evidence of how environmental toxins, absorbed along the digestive tract or inhaled through the lungs, affect the host cellular response. We particularly address the consequences of environmental toxins on the immune response and the microbiome at the gut and lung barrier sites. Additionally, this review highlights findings showing the potential contribution of environmental toxins to an increased risk of stroke. A better understanding of the biological mechanisms underlying exposure to environmental toxins has the potential to mitigate stroke risk and other neurological disorders.

Microplastics and Oxidative Stress-Current Problems and Prospects

Microplastics (MPs) are plastic particles between 0.1 and 5000 µm in size that have attracted considerable attention from the scientific community and the general public, as they threaten the environment. Microplastics contribute to various harmful effects, including lipid peroxidation, DNA damage, activation of mitogen-activated protein kinase pathways, cell membrane breakages, mitochondrial dysfunction, lysosomal defects, inflammation, and apoptosis. They affect cells, tissues, organs, and overall health, potentially contributing to conditions like cancer and cardiovascular disease. They pose a significant danger due to their widespread occurrence in food. In recent years, information has emerged indicating that MPs can cause oxidative stress (OS), a known factor in accelerating the aging of organisms. This comprehensive evaluation exposed notable variability in the reported connection between MPs and OS. This work aims to provide a critical review of whether the harmfulness of plastic particles that constitute environmental contaminants may result from OS through a comprehensive analysis of recent research and existing scientific literature, as well as an assessment of the characteristics of MPs causing OS. Additionally, the article covers the analytical methodology used in this field. The conclusions of this review point to the necessity for further research into the effects of MPs on OS.

Effects of micro/nanoplastics on oxidative damage and serum biochemical parameters in rats and mice: a meta-analysis

Micro/nanoplastics (MNPs) are emerging as environmental pollutants with potential threats to human health. The accumulation of MNPs in the body can cause oxidative stress and increase the risk of cardiovascular disease (CVD). With the aim to systematically evaluate the extent of MNPs-induced oxidative damage and serum biochemical parameters in rats and mice, a total of 36 eligible articles were included in this meta-analysis study. The results reported that MNPs can significantly increase the levels of oxidants such as reactive oxygen species (ROS) and malondialdehyde (MDA) (P < 0.05), and resulted in notable increase in serum biochemical parameters including aspartate aminotransferase (AST) and alanine aminotransferase (ALT) (P < 0.05). Conversely, MNPs significantly reduced levels of antioxidants such as superoxide dismutase (SOD), glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT) (P < 0.05). Subgroup analysis revealed that smaller MNPs with oral administration and prolonged treatment, were associated with more pronounced oxidative stress and enhanced serum biochemical parameters alteration. In addition, after affected by MNPs, the levels of ALT and AST in liver group (SMD = 2.26, 95% CI = [1.59, 2.94] and SMD = 3.10, 95% CI = [1.25, 4.94]) were higher than those in other organs. These comprehensive results provide a scientific foundation for devising strategies to prevent MNPs-induced damage, contributing to solution of this environmental and health challenge.

Impact of the Oral Administration of Polystyrene Microplastics on Hepatic Lipid, Glucose, and Amino Acid Metabolism in C57BL/6Korl and C57BL/6-Lepem1hwl/Korl Mice

The impact of microplastics (MPs) on the metabolic functions of the liver is currently unclear and not completely understood. To investigate the effects of the administration of MPs on the hepatic metabolism of normal and obese mice, alterations in the lipid, glucose (Glu), and amino acid regulation pathways were analyzed in the liver and adipose tissues of C57BL/6Korl (wild type, WT) or C57BL/6-Lepem1hwl/Korl mice (leptin knockout, Lep KO) orally administered polystyrene (PS) MPs for 9 weeks. Significant alterations in the lipid accumulation, adipogenesis, lipogenesis, and lipolysis pathways were detected in the liver tissue of MP-treated WT and Lep KO mice compared to the vehicle-treated group. These alterations in their liver tissues were accompanied by an upregulation of the serum lipid profile, as well as alterations in the adipogenesis, lipogenesis, and lipolysis pathways in the adipose tissues of MP-treated WT and Lep KO mice. Specifically, the level of leptin was increased in the adipose tissues of MP-treated WT mice without any change in their food intake. Also, MP-induced disruptions in the glycogenolysis, Glu transporter type 4 (GLUT4)-5' AMP-activated protein kinase (AMPK) signaling pathway, levels of lipid intermediates, and the insulin resistance of the liver tissues of WT and Lep KO mice were observed. Furthermore, the levels of seven endogenous metabolites were remarkably changed in the serum of WT and Lep KO mice after MP administrations. Finally, the impact of the MP administration observed in both types of mice was further verified in differentiated 3T3-L1 adipocytes and HepG2 cells. Thus, these results suggest that the oral administration of MPs for 9 weeks may be associated with the disruption of lipid, Glu, and amino acid metabolism in the liver tissue of obese WT and Lep KO mice.

Combined exposure to lead and microplastics increased risk of glucose metabolism in mice via the Nrf2/NF-κB pathway

The purpose of this study was to explore the effects of combined lead (Pb) and two types of microplastic (MP) (polyvinyl chloride [PVC] and polyethylene [PE]) exposure on glucose metabolism and investigate the role of the nuclear factor erythroid 2-related factor 2 (Nrf2)/nuclear factor-kappa B (NF-κB) signaling pathway in mediating these effects in mice. Adult C57BL/6J mice were randomly divided into four groups: control, Pb (100 mg/L), MPs (containing 10 mg/L PE and PVC), and Pb + MPs, each of which was treated with drinking water. Treatments were conducted for 6 weeks. Co-exposure to Pb + MPs exhibited increase glycosylated serum protein levels, insulin resistance, and damaged glucose tolerance compared with the control mice. Additionally, treatment with Pb + MPs caused more severe damage to hepatocytes than when exposed to them alone concomitantly, exposed to Pb + MPs exhibited improved the levels of interleukin-6, tumor necrosis factor-alpha, and malondialdehyde, but reduced superoxide dismutase, glutathione peroxidase, and catalase assay in livers. Furthermore, they increase the Kelch-like ECH-associated protein 1 (Keap1) and phosphorylated p-NF-κB protein levels but reduced the protein levels of heme oxygenase-1 and Nrf2, as well as increased Keap1 mRNA and Nrf2 mRNA. Co-exposure to Pb + MP impacts glucose metabolism via the Nrf2 /NF-κB pathway.

Mind over Microplastics: Exploring Microplastic-Induced Gut Disruption and Gut-Brain-Axis Consequences

As environmental plastic waste degrades, it creates an abundance of diverse microplastic particles. Consequently, microplastics contaminate drinking water and many staple food products, meaning the oral ingestion of microplastics is an important exposure route for the human population. Microplastics have long been considered inert, however their ability to promote microbial dysbiosis as well as gut inflammation and dysfunction suggests they are more noxious than first thought. More alarmingly, there is evidence for microplastics permeating from the gut throughout the body, with adverse effects on the immune and nervous systems. Coupled with the now-accepted role of the gut-brain axis in neurodegeneration, these findings support the hypothesis that this ubiquitous environmental pollutant is contributing to the rising incidence of neurodegenerative diseases, like Alzheimer's disease and Parkinson's disease. This comprehensive narrative review explores the consequences of oral microplastic exposure on the gut-brain-axis by considering current evidence for gastrointestinal uptake and disruption, immune activation, translocation throughout the body, and neurological effects. As microplastics are now a permanent feature of the global environment, understanding their effects on the gut, brain, and whole body will facilitate critical further research and inform policy changes aimed at reducing any adverse consequences.

Analysing micro- and nanoplastics with cutting-edge infrared spectroscopy techniques: a critical review

The escalating prominence of micro- and nanoplastics (MNPs) as emerging anthropogenic pollutants has sparked widespread scientific and public interest. These minuscule particles pervade the global environment, permeating drinking water and food sources, prompting concerns regarding their environmental impacts and potential risks to human health. In recent years, the field of MNP research has witnessed the development and application of cutting-edge infrared (IR) spectroscopic instruments. This review focuses on the recent application of advanced IR spectroscopic techniques and relevant instrumentation to analyse MNPs. A comprehensive literature search was conducted, encompassing articles published within the past three years. The findings revealed that Fourier transform infrared (FTIR) spectroscopy stands as the most used technique, with focal plane array FTIR (FPA-FTIR) representing the cutting edge in FTIR spectroscopy. The second most popular technique is quantum cascade laser infrared (QCL-IR) spectroscopy, which has facilitated rapid analysis of plastic particles. Following closely is optical photothermal infrared (O-PTIR) spectroscopy, which can furnish submicron spatial resolution. Subsequently, there is atomic force microscopy-based infrared (AFM-IR) spectroscopy, which has made it feasible to analyse MNPs at the nanoscale level. The most advanced IR instruments identified in articles covered in this review were compared. Comparison metrics encompass substrates/filters, data quality, spatial resolution, data acquisition speed, data processing and cost. The limitations of these IR instruments were identified, and recommendations to address these limitations were proposed. The findings of this review offer valuable guidance to MNP researchers in selecting suitable instrumentation for their research experiments, thereby facilitating advancements in research aimed at enhancing our understanding of the environmental and human health risks associated with MNPs.

Polystyrene nanoplastic and engine oil synergistically intensify toxicity in Nile tilapia, Oreochromis niloticus : Polystyrene nanoplastic and engine oil toxicity in Nile tilapia

Polystyrene nanoplastic (PS-NPs) and Engine oil (EO) pose multiple ecotoxic effects with increasing threat to fish ecosystems. The current study investigated the toxicity of 15 days exposure to PS-NPs and / or EO to explore their combined synergistic effects on Nile tilapia, Oreochromis niloticus (O. niloticus). Hematobiochemical parameters, proinflammatory cytokines, and oxidative stress biomarkers as well as histological alterations were evaluated. The experimental design contained 120 acclimated Nile tilapia distributed into four groups, control, PS-NPs (5 mg/L), EO (1%) and their combination (PS-NPs + EO). After 15-days of exposure, blood and tissue samples were collected from all fish experimental groups. Results indicated that Nile tilapia exposed to PS-NPs and / or EO revealed a significant decrease in almost all the measured hematological parameters in comparison to the control, whereas WBCs and lymphocyte counts were significantly increased in the combined group only. Results clarified that the combined PS-NPs + EO group showed the maximum decrease in RBCs, Hb, MCH and MCHC, and showed the maximum significant rise in interleukin-1β (IL-1β), and interleukin-6 (IL-6) in comparison to all other exposed groups. Meanwhile, total antioxidant capacity (TAC) showed a significant (p < 0.05) decline only in the combination group, whereas reduced glutathione (GSH) showed a significant decline in all exposed groups in comparison to the control. Both malondialdehyde (MDA) and aspartate aminotransferase (AST) showed a significant elevation only in the combination group. Uric acid showed the maximum elevation in the combination group than all other groups, whereas creatinine showed significant elevation in the EO and combination group when compared to the control. Furthermore, the present experiment proved that exposure to these toxicants either individually or in combination is accompanied by pronounced histomorpholgical damage characterized by severe necrosis and hemorrhage of the vital organs of Nile tilapia, additionally extensively inflammatory conditions with leucocytes infiltration. We concluded that combination exposure to both PS-NPs and EO caused severe anemia, extreme inflammatory response, oxidative stress, and lipid peroxidation effects, thus they can synergize with each other to intensify toxicity in fish.

Nrf2-mediated ferroptosis of spermatogenic cells involved in male reproductive toxicity induced by polystyrene nanoplastics in mice

Microplastics (MPs) and nanoplastics (NPs) have become hazardous materials due to the massive amount of plastic waste and disposable masks, but their specific health effects remain uncertain. In this study, fluorescence-labeled polystyrene NPs (PS-NPs) were injected into the circulatory systems of mice to determine the distribution and potential toxic effects of NPs in vivo. Interestingly, whole-body imaging found that PS-NPs accumulated in the testes of mice. Therefore, the toxic effects of PS-NPs on the reproduction systems and the spermatocytes cell line of male mice, and their mechanisms, were investigated. After oral exposure to PS-NPs, their spermatogenesis was affected and the spermatogenic cells were damaged. The spermatocyte cell line GC-2 was exposed to PS-NPs and analyzed using RNA sequencing (RNA-seq) to determine the toxic mechanisms; a ferroptosis pathway was found after PS-NP exposure. The phenomena and indicators of ferroptosis were then determined and verified by ferroptosis inhibitor ferrostatin-1 (Fer-1), and it was also found that nuclear factor erythroid 2-related factor 2 (Nrf2) played an important role in spermatogenic cell ferroptosis induced by PS-NPs. Finally, it was confirmed in vivo that this mechanism of Nrf2 played a protective role in PS-NPs-induced male reproductive toxicity. This study demonstrated that PS-NPs induce male reproductive dysfunction in mice by causing spermatogenic cell ferroptosis dependent on Nrf2.

Modulation of Gut Microbial Metabolism by Cyanidin-3-O-Glucoside in Mitigating Polystyrene-Induced Colonic Inflammation: Insights from 16S rRNA Sequencing and Metabolomics

Microplastics derived from plastic waste have emerged as a pervasive environmental pollutant with potential transfer and accumulation through the food chain, thus posing risks to both ecosystems and human health. The gut microbiota, tightly intertwined with metabolic processes, exert substantial influences on host physiology by utilizing dietary compounds and generating bacterial metabolites such as tryptophan and bile acid. Our previous studies have demonstrated that exposure to microplastic polystyrene (PS) disrupts the gut microbiota and induces colonic inflammation. Meanwhile, intervention with cyanidin-3-O-glucoside (C3G), a natural anthocyanin derived from red bayberry, could mitigate colonic inflammation by reshaping the gut bacterial composition. Despite these findings, the specific influence of gut bacteria and their metabolites on alleviating colonic inflammation through C3G intervention remains incompletely elucidated. Therefore, employing a C57BL/6 mouse model, this study aims to investigate the mechanisms underlying how C3G modulates gut bacteria and their metabolites to alleviate colonic inflammation. Notably, our findings demonstrated the efficacy of C3G in reversing the elevated levels of pro-inflammatory cytokines (IL-6, IL-1β, and TNF-α) and the upregulation of mRNA expression (Il-6, Il-1β, and Tnf-α) induced by PS exposure. Meanwhile, C3G effectively inhibited the reduction in levels (IL-22, IL-10, and IL-4) and the downregulation of mRNA expression (Il-22, Il-10, and Il-4) of anti-inflammatory cytokines induced by PS exposure. Moreover, PS-induced phosphorylation of the transcription factor NF-κB in the nucleus, as well as the increased level of protein expression of iNOS and COX-2 in the colon, were inhibited by C3G. Metabolisms of gut bacterial tryptophan and bile acids have been extensively implicated in the regulation of inflammatory processes. The 16S rRNA high-throughput sequencing disclosed that PS treatment significantly increased the abundance of pro-inflammatory bacteria (Desulfovibrio, norank_f_Oscillospiraceae, Helicobacter, and Lachnoclostridium) while decreasing the abundance of anti-inflammatory bacteria (Dubosiella, Akkermansia, and Alistipes). Intriguingly, C3G intervention reversed these pro-inflammatory changes in bacterial abundances and augmented the enrichment of bacterial genes involved in tryptophan and bile acid metabolism pathways. Furthermore, untargeted metabolomic analysis revealed the notable upregulation of metabolites associated with tryptophan metabolism (shikimate, l-tryptophan, indole-3-lactic acid, and N-acetylserotonin) and bile acid metabolism (3b-hydroxy-5-cholenoic acid, chenodeoxycholate, taurine, and lithocholic acid) following C3G administration. Collectively, these findings shed new light on the protective effects of dietary C3G against PS exposure and underscore the involvement of specific gut bacterial metabolites in the amelioration of colonic inflammation.

Microplastics, their abundance, and distribution in water and sediments in North Chennai, India: An assessment of pollution risk and human health impacts

Plastic particles, measuring <5 mm in size, mainly originate from larger plastic debris undergoing degradation, fragmenting into even smaller fragments. The goal was to analyze the spatial diversity and polymer composition of microplastics (MPs) in North Chennai, South India, aiming to evaluate their prevalence and features like composition, dimensions, color, and shape. In 60 sediment samples, a combined count of 1589 particles were detected, averaging 26 particles per 5 g-1 of dry sediment. The water samples from the North Chennai vicinity encompassed a sum of 1588 particles across 71 samples, with an average of 22 items/L. The majority of MPs ranged in size from 1 mm to 500 μm. The ATR-FTIR results identified the predominant types of MPs as polystyrene, polyvinyl chloride, polyethylene, polyethylene terephthalate, and polypropylene in sediment and water. The spatial variation analysis revealed high MPs concentration in landfill sites, areas with dense populations, and popular tourist destinations. The pollution load index in water demonstrated that MPs had contaminated all stations. Upon evaluating the polymeric and pollution risks, it was evident that they ranged from 5.13 to 430.15 and 2.83 to 15,963.2, which is relatively low to exceedingly high levels. As the quantity of MPs and hazardous polymers increased, the level of pollution and corresponding risks also escalated significantly. The existence of MPs in lake water, as opposed to open well water, could potentially pose a cancer risk for both children and adults who consume it. Detecting MPs in water samples highlights the significance of implementing precautionary actions to alleviate the potential health hazards they create.

Toxicological effects of microplastics in renal ischemia-reperfusion injury

The widespread presence of microplastics (MPs) in the environment poses a significant threat to biological survival and human health. However, our understanding of the toxic effects of MPs on the kidneys remains limited. This study aimed to investigate the underlying mechanism of the toxic effects of MPs on the kidneys using an ischemia-reperfusion (IR) mouse model. Four-week-old ICR mice were exposed to 0.5 μm MPs for 12 weeks prior to IR injury. The results showed that MPs exposure could aggravate the IR-induced damage to renal tubules and glomeruli. Although there were no significant changes in blood urea nitrogen and serum creatinine levels 7 days after IR, MPs treatment resulted in a slight increase in both parameters. In addition, the expression levels of inflammatory factors (MCP-1 and IL-6) at the mRNA level, as well as macrophage markers (CD68 and F4/80), were significantly higher in the MPs + IR group than in the Sham group after IR. Furthermore, MPs exposure exacerbated IR-induced renal fibrosis. Importantly, the expression of pyroptosis-related genes, including NLRP3, ASC, GSDMD, cleaved caspase-1, and IL-18, was significantly upregulated by MPs, indicating that MPs exacerbate pyroptosis in the context of renal IR. In conclusion, our findings suggest that MPs exposure can aggravate renal IR-induced pyroptosis by activating NLRP3-GSDMD signaling.

In Vivo Tissue Distribution of Polystyrene or Mixed Polymer Microspheres and Metabolomic Analysis after Oral Exposure in Mice

BACKGROUND

Global plastic use has consistently increased over the past century with several different types of plastics now being produced. Much of these plastics end up in oceans or landfills leading to a substantial accumulation of plastics in the environment. Plastic debris slowly degrades into microplastics (MPs) that can ultimately be inhaled or ingested by both animals and humans. A growing body of evidence indicates that MPs can cross the gut barrier and enter into the lymphatic and systemic circulation leading to accumulation in tissues such as the lungs, liver, kidney, and brain. The impacts of mixed MPs exposure on tissue function through metabolism remains largely unexplored.

OBJECTIVES

This study aims to investigate the impacts of polymer microspheres on tissue metabolism in mice by assessing the microspheres ability to translocate across the gut barrier and enter into systemic circulation. Specifically, we wanted to examine microsphere accumulation in different organ systems, identify concentration-dependent metabolic changes, and evaluate the effects of mixed microsphere exposures on health outcomes.

METHODS

To investigate the impact of ingested microspheres on target metabolic pathways, mice were exposed to either polystyrene (5 μ m ) microspheres or a mixture of polymer microspheres consisting of polystyrene (5 μ m ), polyethylene (1 - 4 μ m ), and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid) (5 μ m ). Exposures were performed twice a week for 4 weeks at a concentration of either 0, 2, or 4 mg / week via oral gastric gavage. Tissues were collected to examine microsphere ingress and changes in metabolites.

RESULTS

In mice that ingested microspheres, we detected polystyrene microspheres in distant tissues including the brain, liver, and kidney. Additionally, we report on the metabolic differences that occurred in the colon, liver, and brain, which showed differential responses that were dependent on concentration and type of microsphere exposure.

DISCUSSION

This study uses a mouse model to provide critical insight into the potential health implications of the pervasive issue of plastic pollution. These findings demonstrate that orally consumed polystyrene or mixed polymer microspheres can accumulate in tissues such as the brain, liver, and kidney. Furthermore, this study highlights concentration-dependent and polymer type-specific metabolic changes in the colon, liver, and brain after plastic microsphere exposure. These results underline the mobility within and between biological tissues of MPs after exposure and emphasize the importance of understanding their metabolic impact. https://doi.org/10.1289/EHP13435.

Exploring the potential and challenges of developing physiologically-based toxicokinetic models to support human health risk assessment of microplastic and nanoplastic particles

Microplastics (MPs) and nanoplastics (NPs) pollution has emerged as a significant and widespread environmental issue. Humans are inevitably exposed to MPs and NPs via ingestion, inhalation, and dermal contacts from various sources. However, mechanistic knowledge of their distribution, interaction, and potency in the body is still lacking. To address this knowledge gap, we have undertaken the task of elucidating the toxicokinetic (TK) behaviors of MPs and NPs, aiming to provide mechanistic information for constructing a conceptual physiologically based toxicokinetic (PBTK) model to support in silico modeling approaches. Our effort involved a thorough examination of the existing literature and data collation on the presence of MPs in the human body and in vitro/ex vivo/in vivo biodistribution across various cells and tissues. By comprehending the absorption, distribution, metabolism, and excretion mechanisms of MPs and NPs in relation to their physicochemical attributes, we established a foundational understanding of the link between external exposure and internal tissue dosimetry. We observed that particle size and surface chemistry have been thoroughly explored in previous experimental studies. However, certain attributes, such as polymer type, shape, and biofilm/biocorona, warrant attention and further examination. We discussed the fundamental disparities in TK properties of MPs/NPs from those of engineered nanoparticles. We proposed a preliminary PBTK framework with several possible modeling approaches and discussed existing challenges for further investigation. Overall, this article provides a comprehensive compilation of existing TK data of MPs/NPs, a critical overview of TK processes and mechanisms, and proposes potential PBTK modeling approaches, particularly regarding their applicability to the human system, and outlines future perspectives for developing PBTK models and their integration into human health risk assessment of MPs and NPs.

Combined effect of polystyrene nanoplastic and di-n-butyl phthalate on testicular health of male Swiss albino mice: analysis of sperm-related parameters and potential toxic effects

Plastics, especially polystyrene nanoplastic particles (PSNPs), are known for their durability and absorption properties, allowing them to interact with environmental pollutants such as di-n-butyl phthalate (DBP). Previous research has highlighted the potential of these particles as carriers for various pollutants, emphasizing the need to understand their environmental impact comprehensively. This study focuses on the subchronic exposure of male Swiss albino mice to PSNP and DBP, aiming to investigate their reproductive toxicity between these pollutants in mammalian models. The primary objective of this study is to examine the reproductive toxicity resulting from simultaneous exposure to PSNP and DBP in male Swiss albino mice. The study aims to analyze sperm parameters, measure antioxidant enzyme activity, and conduct histopathological and morphometric examinations of the testis. By investigating the individual and combined effects of PSNP and DBP, the study seeks to gain insights into their impact on the reproductive profile of male mice, emphasizing potential synergistic interactions between these environmental pollutants. Male Swiss albino mice were subjected to subchronic exposure (60 days) of PSNP (0.2 mg/m, 50 nm size) and DBP (900 mg/kg bw), both individually and in combination. Various parameters, including sperm parameters, antioxidant enzyme activity, histopathological changes, and morphometric characteristics of the testis, were evaluated. The Johnsen scoring system and histomorphometric parameters were employed for a comprehensive assessment of spermatogenesis and testicular structure. The study revealed non-lethal effects within the tested doses of PSNP and DBP alone and in combination, showing reductions in body weight gain and testis weight compared to the control. Individual exposures and the combination group exhibited adverse effects on sperm parameters, with the combination exposure demonstrating more severe outcomes. Structural abnormalities, including vascular congestion, Leydig cell hyperplasia, and the extensive congestion in tunica albuginea along with both ST and Leydig cell damage, were observed in the testis, underscoring the reproductive toxicity potential of PSNP and DBP. The Johnsen scoring system and histomorphometric parameters confirmed these findings, providing interconnected results aligning with observed structural abnormalities. The study concludes that simultaneous exposure to PSNP and DBP induces reproductive toxicity in male Swiss albino mice. The combination of these environmental pollutants leads to more severe disruptions in sperm parameters, testicular structure, and antioxidant defense mechanisms compared to individual exposures. The findings emphasize the importance of understanding the interactive mechanisms between different environmental pollutants and their collective impact on male reproductive health. The use of the Johnsen scoring system and histomorphometric parameters provides a comprehensive evaluation of spermatogenesis and testicular structure, contributing valuable insights to the field of environmental toxicology.

Assessing the contribution of plastic-associated obesogenic compounds to cardiometabolic diseases

PURPOSE OF REVIEW

To present recent evidence that strengthens the concept that exogenous pollutants contribute to adipose dysfunction and increased rates of disease and to highlight the ineffective regulation of this risk as industry switches to related but similarly toxic variants.

RECENT FINDINGS

Substitutes for common phthalates and the highly regulated bisphenol A (BPA) show similar deleterious effects on adipocytes. The well tolerated limit for BPA exposure has been reduced in Europe to below the level detected in recent population studies. Additionally, the role for BPA-induced inflammation mediated by interleukin 17a has been described in animal and human studies.

SUMMARY

Despite experimental and associative evidence that supports plastics and plastic associated chemicals deleteriously influencing adipose homeostatasis and contributing to metabolic diseases, structurally related alternate chemicals are being substituted by manufacturers to circumvent trailing regulatory actions.

Obesogenic polystyrene microplastic exposures disrupt the gut-liver-adipose axis

Microplastics (MP) derived from the weathering of polymers, or synthesized in this size range, have become widespread environmental contaminants and have found their way into water supplies and the food chain. Despite this awareness, little is known about the health consequences of MP ingestion. We have previously shown that the consumption of polystyrene (PS) beads was associated with intestinal dysbiosis and diabetes and obesity in mice. To further evaluate the systemic metabolic effects of PS on the gut-liver-adipose tissue axis, we supplied C57BL/6J mice with normal water or that containing 2 sizes of PS beads (0.5 and 5 µm) at a concentration of 1 µg/ml. After 13 weeks, we evaluated indices of metabolism and liver function. As observed previously, mice drinking the PS-containing water had a potentiated weight gain and adipose expansion. Here we found that this was associated with an increased abundance of adipose F4/80+ macrophages. These exposures did not cause nonalcoholic fatty liver disease but were associated with decreased liver:body weight ratios and an enrichment in hepatic farnesoid X receptor and liver X receptor signaling. PS also increased hepatic cholesterol and altered both hepatic and cecal bile acids. Mice consuming PS beads and treated with the berry anthocyanin, delphinidin, demonstrated an attenuated weight gain compared with those mice receiving a control intervention and also exhibited a downregulation of cyclic adenosine monophosphate (cAMP) and peroxisome proliferator-activated receptor (PPAR) signaling pathways. This study highlights the obesogenic role of PS in perturbing the gut-liver-adipose axis and altering nuclear receptor signaling and intermediary metabolism. Dietary interventions may limit the adverse metabolic effects of PS consumption.