Impact of microplastics on the intestinal microbiota: A systematic review of preclinical evidence

Nanoplastic exposure affects the intestinal microbiota of adult Drosophila flies

Micro- and nanoplastics (MNPLs) are emerging environmental pollutants that have garnered significant attention over the past few decades due to their detrimental effects on human health through various exposure pathways. This study investigates the impact of MNPLs on gut microbiota, utilizing Drosophila melanogaster as a model organism. Drosophila was selected for its microbiota's similarities to humans and its established role as an accessible and well-characterized model system. To analyze microbiota, full-length 16S rRNA gene sequencing was performed using the Nanopore sequencing platform, enabling comprehensive profiling of the microbial populations present in the samples. As models of MNPLs, two commercial polystyrene nanoplastics (PS-NPLs, 61.20 and 415.22 nm) and one lab-made polylactic acid nanoplastic (PLA-NPLs, 463.90 nm) were selected. As a positive control, zinc oxide nanoparticles (ZnO-NPs) were used. The observed findings revealed that exposure to MNPLs induced notable alterations in gut microbiota, including a reduction in bacterial abundance and shifts in species composition. These results suggest that MNPLs exposure can lead to microbial dysbiosis and potential gut health disruptions through its interaction, either with the gut epithelial barrier or directly with the resident microorganisms.

Potential Biological Impacts of Microplastics and Nanoplastics on Farm Animals: Global Perspectives with Insights from Bangladesh

Microplastics (MPs) and nanoplastics (NPs), formed through the degradation of larger plastic materials, are emerging pollutants of significant concern. While their impact on aquatic ecosystems is well documented, their effects on terrestrial, especially farm animals remain underexplored. This review assesses the potential threats of MPs and NPs to Bangladesh's livestock sector by analyzing the results of experimental models and environmental studies. In Bangladesh, MPs and NPs have been detected in agricultural soils, air, water bodies, and aquatic organisms, indicating possible entry into animal systems through contaminated feed, water, and inhalation. Once internalized, these particles may trigger oxidative stress, inflammation, and tissue damage, impairing vital biological systems. Documented health consequences include reduced fertility, hematotoxicity, gut microbiota imbalance, gut-brain axis disruption, skeletal disorders, and metabolic dysfunction. Additionally, MPs and NPs can induce genomic changes, including altered gene expression and DNA hypomethylation, intensifying physiological damage and reducing productivity. Therefore, managing plastic contamination is vital in protecting animal health, ensuring food safety, and preserving human well-being around the globe, especially in vulnerable regions like Bangladesh. Given the critical role of livestock and poultry in ensuring food security and public health, the findings highlight an urgent need for comprehensive research and mitigation strategies.

Exploring the efficacy of Benincasa hispida extract on obesity linked inflammatory bowel disease by integrating computational analysis and experimental validations

The association of obesity with inflammatory bowel disease (IBD) can be understood by the intricate role of pro- and anti-inflammatory cytokines, especially adipokines, which are secreted by adipose tissue and are responsible for IBD because of their structural similarity with tumor necrosis factor-alpha (TNF-α), an important cytokine involved in IBD pathogenesis. The current study was carried out to evaluate the therapeutic potential of Benincasa hispida in obesity-associated IBD. Approximately 18 compounds sourced from Benincasa hispida (Thunb.) were comprehensively analyzed, among which 11 presented favorable drug-likeness scores and adherence to Lipinski's Rule of Five. Various methodologies, including compound-gene set pathway enrichment analysis, network pharmacology, docking studies, and molecular dynamics simulations, have been employed. Safety assessments via Protox confirmed the nontoxic nature of these compounds, which is crucial for their therapeutic potential. Through Venn diagram analysis of the Gene Card and OMIM databases, proteins associated with obesity and IBD management were pinpointed. Pathway enrichment analysis revealed 810 targets across 192 distinct pathways, with 8 directly related to the pathogenesis of obesity and IBD. Notable therapeutic targets, such as MTOR, were identified through STRING and KEGG pathway database analyses, shedding light on the molecular pathways modulated by these protein targets. Interactions among compounds, proteins, and pathways were visualized via Cytoscape 3.6.1. Furthermore, the compounds were docked with the protein target via AutoDock 4.2, and the compound ajmalin exhibited the highest binding affinity with the MTOR protein, with a binding energy of -7.8 kcal/mol; later, a dynamic study was performed for the ajmaline and protein complex. These findings shed light on the potential efficacy of Benincasa hispida in targeting crucial pathways for managing obesity and IBD. Hence, in vivo studies involving Wistar rats exposed to microplastics and monosodium glutamate (MSG) were carried out to evaluate the potential of Benincasa hispida extracts in mitigating obesity-related IBD. Fecal lipid analysis revealed alterations associated with these conditions, whereas histopathological examinations of the liver and intestine revealed the inflammatory changes induced by MSG and microplastics. The protective effects of this extract on liver and intestinal histology suggest promising avenues for further investigations, emphasizing its potential as a therapeutic intervention for IBD and obesity.

Unraveling the Impact of Microplastic-Tetracycline Composite Pollution on the Moon Jellyfish Aurelia aurita: Insights from Its Microbiome

Microplastics have emerged as a pervasive marine contaminant, with extreme concentrations reported in deep-sea sediments (e.g., 1.9 million particles/m2) and localized accumulations near Antarctic research stations. Particular concern has been raised regarding their synergistic effects with co-occurring antibiotics, which may potentiate toxicity and facilitate antibiotic resistance gene dissemination through microbial colonization of plastic surfaces. To investigate these interactions, a 185-day controlled exposure experiment was conducted using Aurelia aurita polyps. Factorial combinations of microplastics (0, 0.1, 1 mg/L) and tetracycline (0, 0.5, 5 mg/L) were employed to simulate environmentally relevant pollution scenarios. Microbiome alterations were characterized using metagenomic approaches. Analysis revealed that while alpha and beta diversity measures remained unaffected at environmental concentrations, significant shifts occurred in the relative abundance of dominant bacterial taxa, including Pseudomonadota, Actinomycetota, and Mycoplasmatota. Metabolic pathway analysis demonstrated perturbations in key functional categories including cellular processes and environmental signal transduction. Furthermore, microplastic exposure was associated with modifications in polyp life-stage characteristics, suggesting potential implications for benthic-pelagic population dynamics. These findings provide evidence for the impacts of microplastic-antibiotic interactions on cnidarian holobionts, with ramifications for predicting jellyfish population responses in contaminated ecosystems.

Urinary Metabolomics of Plastic Manufacturing Workers: A Pilot Study

The plastic manufacturing industry has a crucial role in the global economy with a significant impact in a wide range of fields. The chemical risk to which workers are potentially exposed is difficult to characterize and strictly related to both the products and processes adopted. Among the chemicals used, we can cite styrene, phenol, butadiene and phthalates, but nano- and microplastic particles can also be released in the work environment. In this pilot study, we present for the first time an NMR-based metabolomic approach for assessing urinary profiles of workers employed in a plastic manufacturing company. Urine samples from twelve workers and thirteen healthy volunteers were collected and analyzed by NMR spectroscopy. Forty-six urinary metabolites belonging to different chemical classes were univocally identified and quantified. The dataset so obtained was then subjected to multivariate statistical analysis to characterize each profile and highlight any differences. An alteration in some metabolites involved in several pathways, such as amino acid metabolism and NAD metabolism, was found, and a strong impact on gut microflora was also speculated. Ultimately, our work has the objective of adding a tile to the knowledge of biological effects possibly related to occupational exposure even if it is below the threshold limit values.

Postbiotic Sodium Butyrate Mitigates Hypertension and Kidney Dysfunction in Juvenile Rats Exposed to Microplastics

BACKGROUND

Plastic production has led to widespread microplastic (MP) pollution, with children more vulnerable to MPs than adults. However, the mechanisms linking MP exposure to hypertension and kidney disease in children remain unclear. This study explored whether sodium butyrate, a short-chain fatty acid (SCFA) with antioxidant and anti-inflammatory properties, could mitigate MP-induced hypertension and kidney damage in juvenile rats.

METHODS

Male Sprague-Dawley rats (3 weeks old) were randomly assigned to four groups (n = 8/group): control, low-dose MP (1 mg/L), high-dose MP (10 mg/L), and high-dose MP with sodium butyrate (400 mg/kg/day). Rats were euthanized at 12 weeks.

RESULTS

High-dose MP exposure impaired kidney function and increased blood pressure, which were alleviated by sodium butyrate through reduced oxidative stress, modulation of gut microbiota, increased plasma butyric acid levels, and enhanced renal SCFA-sensing G protein-coupled receptor 43 expression.

CONCLUSIONS

Sodium butyrate holds potential for mitigating MP-induced hypertension by reducing oxidative stress, modulating the gut microbiota, and elevating butyric acid levels.

The Effects of Microplastics on Musculoskeletal Disorder; A Narrative Review

PURPOSE OF REVIEW

The physical health impacts of microplastics have received increasing attention in recent years. However, limited data impedes a full understanding of the internal exposure to microplastics, especially concerning the musculoskeletal system. The purpose of this review is to summarize the recent literature regarding the effects of microplastics on the musculoskeletal system.

RECENT FINDINGS

Microplastics have been shown to cause abnormal endochondral ossification and disrupt the normal function of pre-osteoblasts, osteocyte-like cells, and pre-osteoclasts through gene mutations, endoplasmic reticulum stress induction, and reduced autophagosome formation in bone growth areas. Although there are few reports on their effects on muscle, it has been noted that microplastics inhibit energy and lipid metabolism, decrease type I muscle fiber density, impair muscle angiogenesis, cause muscle atrophy, and increase lipid deposition. Only a few recent studies have shown that microplastics interfere with the normal function of bone growth-related cells and reduce muscle mass and quality. This review underscores the need for further research into other parts of the musculoskeletal system and studies using human tissues at the disease level.

Microplastics in seafood: Navigating the silent health threat and intestinal implications through a One Health food safety lens

This systematic review revealed microplastic (MP) contamination and conducted hazard risk assessment in various seafood species of different geographic locations. Evidence was available on fish, crustaceans, and mollusks, with most studies from China reporting 19 seafood species containing the highest variety of total MP polymers. The maximum percentage of MPs in terms of size, composition, shape, and color was attributed to 100-1500 µm, polyethylene terephthalate (PET), fibers, and blue color, respectively. Aquatic life in brackish and marine ecosystems harbored higher levels of MPs than freshwater organisms. Crustacean species Thenus orientalis (flathead lobster) off the coasts of Iran were the most heavily loaded with 460.2 MPs/individual. Meta-analysis revealed high statistical and model heterogeneity of MP content in fish (mean 1.11 MPs/individual, 95 % confidence interval (CI)= 0.3-1.92) and shellfish (1.43 MPs/individual, 95 % CI= -0.35-3.21). The highest MP contamination factor (CF) was estimated in marine carnivorous Plectropomus leopardus (leopard coral trout) from Australia/Fiji (CF= 3.06), omnivorous Portunus sanguinolentus (three spot crab) from India (CF= 5.44), and filter-feeding Chlamys nobilis (noble scallop) from China (CF= 3.38), with the highest pollution risk index (PRI) values of 366877.6, 46437.5, and 45672.2, respectively. Studies show that MPs are potential triggers of altered key microbial diversity of Firmicutes, Fusobacteria, Proteobacteria, Actinobacteria, and Bacteroidetes. The dysbiotic properties of MPs increased intestinal permeability and decreased immune system associated with inflammation. In summary, this study provides a significant understanding of the MP abundance in edible seafood species and knowledge of MP risk assessment important to safeguard food safety and human health.

Microplastics and orthodontic aligners: The concerns arising from the modernization of practice through polymers and plastics

Plastic aligners have transformed orthodontics, offering a discreet, comfortable, and aesthetically pleasing alternative to traditional fixed appliances. While they have advantages over fixed appliances, they come with environmental and health concerns due to the use of nonbiodegradable plastics, such as the leaching of Bisphenol-A (BPA) and microplastics that can impact human health directly through ingestion. Studies have shown that plastic aligners release microplastics during use, raising concerns about their potential health effects and environmental pollution. The potential health effects of ingested microplastics extend beyond gut microbiota disruption to impact various systems in the body. Research suggests that microplastic exposure can lead to respiratory complications, cardiovascular risks, and implications for brain health and cognitive function. The mechanisms of microplastic uptake into the body through inhalation, ingestion, and skin contact are essential for understanding how these particles interact with human tissues and organs. By prioritizing patient safety, responsible practices, and advancing scientific knowledge the orthodontic community can work towards mitigating the potential health impacts associated with microplastic exposure from aligners.

Microplastics and human health: unveiling the gut microbiome disruption and chronic disease risks

Microplastics (MPs), defined as plastic particles smaller than 5 mm, are increasingly recognized as environmental contaminants with potential health risks. These emerge as breakdown products of larger plastics and are omnipresent in marine, freshwater, and terrestrial ecosystems. They are primarily composed of polymers such as polyethylene, polypropylene, polystyrene, and additives that enhance their performance. MPs also adsorb harmful environmental chemicals like persistent organic pollutants and heavy metals, posing risks to human and environmental health. Human exposure to MPs occurs mainly through ingestion and inhalation, with MPs detected in food products, water, and even the air. MPs have been shown to accumulate in the gastrointestinal tract, disrupting the gut microbiome, and causing dysbiosis-a harmful imbalance between beneficial and harmful bacteria. This disruption has been linked to various health issues, including gastrointestinal disorders, systemic inflammation, and chronic diseases. Furthermore, the gut-brain axis may be affected, with potential neuroinflammatory consequences. As research continues to unravel the health impacts of MP exposure, understanding the mechanisms of accumulation and the broader implications on human health is crucial. This review highlights the effects of MPs on human health, emphasizing their impact on the gut microbiome. We discuss the potential connections between MP exposure and cardiometabolic and inflammatory diseases, and disorders related to the Gut-Brain Axis. By synthesizing the latest research, this work sheds light on the silent yet pervasive threat posed by MPs and underscores the importance of further studies to understand their health impacts fully.

Links between fecal microplastics and parameters related to metabolic dysfunction-associated steatotic liver disease (MASLD) in humans: An exploratory study

Microplastics (MPs) can persist in the environment and human body. Murine studies showed that exposure to MPs could cause metabolic dysregulation, contributing metabolic dysfunction-associated steatotic liver disease (MASLD) or steatohepatitis (MASH). However, research on the role of MPs in humans is limited. Thus, we aimed to assess links between human fecal MPs and liver histology, gene expression, immune cells and intestinal microbiota (IM). We included 6 lean healthy liver donors and 6 normal liver (obese) and 11 MASH patients. Overall, pre-BSx, we observed no significant differences in fecal MPs between groups. However, fecal MP fibers and total MPs positively correlated with portal and total macrophages and total killer T cells while total fecal MPs were positively correlated with natural killer cells. Additionally, 19 genes related to immune system and apoptosis correlated with fecal MPs at baseline. Fecal MP fibers correlated positively with fecal Bifidobacterium and negatively with Lachnospiraceae. Patients with MASH (n = 11) were re-assessed 12-months post-bariatric surgery (BSx) and we found that those with persistent disease (n = 4) had higher fecal MP fragments than those with normalized liver histology (n = 7). At 12-month post-BSx, MP fragments positively correlated with helper T cells and total MPs positively correlated with natural killer T cells and B cells. Our study is the first to look at 1) the role of MPs in MASH and its association with IM, immune cells and hepatic gene expression and 2) look at the role of MPs longitudinally in MASH persistence following BSx. Future research should further explore this relationship.

Micro/nano plastics in the urinary system: Pathways, mechanisms, and health risks

Micro/Nano plastics (MNPs) pollutants are widespread in the environment, raising significant concerns about their biosafety. Emerging studies indicate that the urinary system is a primary accumulation site for MNPs, leading to severe tissue and functional damage. This review aims to summarize recent research on the potential hazards that MNPs may pose to the urinary system, highlighting the mechanisms of toxicity and the current state of knowledge. Studies have shown that MNPs enter the human body through drinking water, the food chain, inhalation, and skin contact. They may penetrate the bloodstream via the digestive, respiratory, and skin systems, subsequently dispersing to various organs, including the urinary system. The potential accumulation of MNPs in the urinary system might induce cellular oxidative stress, inflammation, apoptosis, autophagy, the "intestine-kidney axis", and other possible toxic mechanisms. These processes could disrupt kidney metabolic functions and promote tissue fibrosis, thereby potentially increasing the risk of urinary system diseases. Despite ongoing research, the understanding of MNPs' impact on the urinary system remains limited. Therefore, this review provides a comprehensive overview of MNPs' potential toxicity mechanisms in the urinary system, highlights key challenges, and outlines future research directions. It offers a theoretical basis for the development of effective protective measures and policies.

Single exposure of food-derived polyethylene and polystyrene microplastics profoundly affects gut microbiome in an in vitro colon model

Microplastics (MPs) are widespread contaminants highly persistent in the environment and present in matrices to which humans are extensively exposed, including food and beverages. MP ingestion occurs in adults and children and is becoming an emerging public health issue. The gastrointestinal system is the most exposed to MP contamination, which can alter its physiology starting from changes in the microbiome. This study investigates by an omic approach the impact of a single intake of a mixture of polyethylene (PE) and polystyrene (PS) MPs on the ecology and metabolic activity of the colon microbiota of healthy volunteers, in an in vitro intestinal model. PE and PS MPs were pooled together in a homogeneous mix, digested with the INFOGEST system, and fermented with MICODE (multi-unit in vitro colon model) at loads that by literature correspond to the possible intake of food-derived MPs of a single meal. Results demonstrated that MPs induced an opportunistic bacteria overgrowth (Enterobacteriaceae, Desulfovibrio spp., Clostridium group I and Atopobium - Collinsella group) and a contextual reduction on abundances of all the beneficial taxa analyzed, with the sole exception of Lactobacillales. This microbiota shift was consistent with the changes recorded in the bacterial metabolic activity.

Isolation and characterization of polyester polyurethane-degrading bacterium Bacillus sp. YXP1

Microorganisms have the potential to be applied for the degradation or depolymerization of polyurethane (PU) and other plastic waste, which have attracted global attention. The appropriate strain or enzyme that can effectively degrade PU is the key to treat PU plastic wastes by biological methods. Here, a polyester PU-degrading bacterium Bacillus sp. YXP1 was isolated and identified from a plastic landfill. Three PU substrates with increasing structure complexities, including Impranil DLN, poly (1,4-butylene adipate)-based PU (PBA-PU), and polyester PU foam, were used to evaluate the degradation capacity of Bacillus sp. YXP1. Under optimal conditions, strain YXP1 could completely degrade 0.5% Impranil DLN within 7 days. After 30 days, the weight loss of polyester PU foam by strain YXP1 was as high as 42.1%. In addition, PBA-PU was applied for degradation pathway analysis due to its clear composition and chemical structure. Five degradation intermediates of PBA-PU were identified, including 4,4'-methylenedianiline (MDA), 1,4-butanediol, adipic acid, and two MDA derivates, indicating that strain YXP1 could depolymerize PBA-PU by the hydrolysis of ester and urethane bonds. Furthermore, the extracellular enzymes produced by strain YXP1 could hydrolyze PBA-PU to generate MDA. Together, this study provides a potential bacterium for the biological treatment of PU plastic wastes and for the mining of functional enzymes.

Early-life exposures and the microbiome: implications for IBD prevention

The early-life period is one of microbiome establishment and immune maturation. Early-life exposures are increasingly being recognised to play an important role in IBD risk. The composition of functions of the gut microbiome in the prenatal, perinatal, and postnatal period may be crucial towards development of health or disease, including IBD, later in life. We herein present a comprehensive summary of the interplay between early-life factors and microbiome perturbations, and their association with risk of IBD. In addition, we provide an overview of host and external factors in early life that are known to impact gut microbiome maturation and exposures implicated in IBD risk. Considering the emerging concept of IBD prevention, we propose strategies to minimise maternal and offspring exposure to potentially harmful variables and recommend protective measures during pregnancy and the postpartum period. This holistic view of early-life factors and microbiome signatures among mothers and their offspring will help frame our current understanding of their importance towards IBD pathogenesis and frame the roadmap for preventive strategies.

Polystyrene microplastics induce kidney injury via gut barrier dysfunction and C5a/C5aR pathway activation

Microplastic is an emerging environmental pollutant with potential health risks. Recent studies have shown that microplastic could impair gut homeostasis in mammals. Although it has been widely demonstrated that gut dyshomeostasis could impact renal health through the gut-kidney axis, the effects of microplastic-induced gut dyshomeostasis on renal health and underlying mechanisms are still largely unknown. In the current work, we found that polystyrene microplastics (PS-MPs) treatment impaired the gut barrier, increased urinary complement-activated product C5a levels and renal C5aR expression, leading to chronic kidney disease-related symptoms in mice. Restoring the gut barrier using an antibiotic mixture effectively alleviated PS-MPs-induced kidney injury, indicating the involvement of the gut-kidney axis in PS-MPs-induced renal injury. Moreover, it also mitigated PS-MPs-induced alterations in urinary C5a levels and renal C5aR expression, suggesting that the renal C5a/C5aR pathway might be involved in PS-MPs' impacts on the gut-kidney axis. Further experiments using a C5aR inhibitor, PMX53, verified the vital role of renal C5a/C5aR pathway activation in the development of kidney injury induced by PS-MPs. Collectively, our results suggest that PS-MPs induce kidney injury in mice by impairing the gut barrier, increasing C5a levels, and ultimately activating the renal C5a/C5aR pathway, highlighting the crucial role of the gut-kidney axis in PS-MPs-induced kidney injury.

Underestimated health risks: Dietary restriction magnify the intestinal barrier dysfunction and liver injury in mice induced by polystyrene microplastics

Microplastics (MPs) have gained significant attention due to their widespread presence in the environment. While studies have been conducted to investigate the risks associated with MPs, the potential effects of MPs on populations with varying dietary habits, such as dietary restriction (DR), remain largely undefined. The sensitivity of the body to invasive contaminants may increase due to insufficient food intake. Here, we aimed to investigate whether dietary restriction could affect the toxicity of MPs in mice. Following a 5-week exposure to 200 μg/L polystyrene microplastics (PSMPs), DR-PSMPs treatment group exhibited significant intestinal barrier dysfunction compared to ND-PSMPs treatment group, as determined by histopathological and biochemical analysis. Dietary restriction worsened liver oxidative stress and bile acid disorder in mice exposed to PSMPs. 16S rRNA sequencing analysis revealed that DR-PSMPs treatment caused alterations in gut microbiota composition, including the downregulation of probiotics abundance and upregulation of pathogenic bacteria abundance. The negative effects caused by PSMPs in mice with dietary restriction could attribute to increased MPs bioaccumulation, declined water intake, reduced probiotics abundance, and elevated pathogenic bacteria abundance, as well as the susceptibility of the dietary restriction individual. Our findings hint that the biological effects of contaminants could be affected by dietary habits.

Effects of microplastics and tetracycline on intestinal injury in mice

Microplastics (MPs) and tetracycline are both emerging environmental pollutants that threaten human health. The toxic impacts of their single and coexposure on the intestine and gut microbiota have not been well studied in mammals. Given the spatial functional characteristics of the intestine, it is important to know whether the toxicities of MPs and tetracycline in different intestinal segments are distinct. This study investigated the pathological and functional injuries of different intestinal segments and the microbial disorder upon exposure to polystyrene microplastics (PS-MPs) and/or tetracycline hydrochloride (TCH). Both PS-MPs and TCH altered the intestinal morphology and induced functional impairment. However, the PS-MPs primarily damaged the colon, while TCH mainly damaged the small intestine, especially the jejunum. Combined treatment evoked ameliorative adverse effects on the intestinal segments except for the ileum. Gut microbiota analysis revealed that PS-MPs and/or TCH decreased gut microbiota diversity, especially PS-MPs. In addition, PS-MPs and TCH affected the microflora metabolic processes, especially protein absorption and digestion. Gut microbiota dysbiosis could partly lead to the physical and functional damage induced by PS-MPs and TCH. These findings enhance our knowledge regarding the hazards of coexisting microplastics and antibiotics for mammalian intestinal health.

Microplastic sources, formation, toxicity and remediation: a review

Microplastic pollution is becoming a major issue for human health due to the recent discovery of microplastics in most ecosystems. Here, we review the sources, formation, occurrence, toxicity and remediation methods of microplastics. We distinguish ocean-based and land-based sources of microplastics. Microplastics have been found in biological samples such as faeces, sputum, saliva, blood and placenta. Cancer, intestinal, pulmonary, cardiovascular, infectious and inflammatory diseases are induced or mediated by microplastics. Microplastic exposure during pregnancy and maternal period is also discussed. Remediation methods include coagulation, membrane bioreactors, sand filtration, adsorption, photocatalytic degradation, electrocoagulation and magnetic separation. Control strategies comprise reducing plastic usage, behavioural change, and using biodegradable plastics. Global plastic production has risen dramatically over the past 70 years to reach 359 million tonnes. China is the world's top producer, contributing 17.5% to global production, while Turkey generates the most plastic waste in the Mediterranean region, at 144 tonnes per day. Microplastics comprise 75% of marine waste, with land-based sources responsible for 80-90% of pollution, while ocean-based sources account for only 10-20%. Microplastics induce toxic effects on humans and animals, such as cytotoxicity, immune response, oxidative stress, barrier attributes, and genotoxicity, even at minimal dosages of 10 μg/mL. Ingestion of microplastics by marine animals results in alterations in gastrointestinal tract physiology, immune system depression, oxidative stress, cytotoxicity, differential gene expression, and growth inhibition. Furthermore, bioaccumulation of microplastics in the tissues of aquatic organisms can have adverse effects on the aquatic ecosystem, with potential transmission of microplastics to humans and birds. Changing individual behaviours and governmental actions, such as implementing bans, taxes, or pricing on plastic carrier bags, has significantly reduced plastic consumption to 8-85% in various countries worldwide. The microplastic minimisation approach follows an upside-down pyramid, starting with prevention, followed by reducing, reusing, recycling, recovering, and ending with disposal as the least preferable option.

Intestinal protein uptake and IgE-mediated food allergy

Food allergy is affecting 5-8% of young children and 2-4% of adults and seems to be increasing in prevalence. The cause of the increase in food allergy is largely unknown but proposed to be influenced by both environmental and lifestyle factors. Changes in intestinal barrier functions and increased uptake of dietary proteins have been suggested to have a great impact on food allergy. In this review, we aim to give an overview of the gastrointestinal digestion and intestinal barrier function and provide a more detailed description of intestinal protein uptake, including the various routes of epithelial transport, how it may be affected by both intrinsic and extrinsic factors, and the relation to food allergy. Further, we give an overview of in vitro, ex vivo and in vivo techniques available for evaluation of intestinal protein uptake and gut permeability in general. Proteins are digested by gastric, pancreatic and integral brush border enzymes in order to allow for sufficient nutritional uptake. Absorption and transport of dietary proteins across the epithelial layer is known to be dependent on the physicochemical properties of the proteins and their digestion fragments themselves, such as size, solubility and aggregation status. It is believed, that the greater an amount of intact protein or larger peptide fragments that is transported through the epithelial layer, and thus encountered by the mucosal immune system in the gut, the greater is the risk of inducing an adverse allergic response. Proteins may be absorbed across the epithelial barrier by means of various mechanisms, and studies have shown that a transcellular facilitated transport route unique for food allergic individuals are at play for transport of allergens, and that upon mediator release from mast cells an enhanced allergen transport via the paracellular route occurs. This is in contrast to healthy individuals where transcytosis through the enterocytes is the main route of protein uptake. Thus, knowledge on factors affecting intestinal barrier functions and methods for the determination of their impact on protein uptake may be useful in future allergenicity assessments and for development of future preventive and treatment strategies.

Influence of ultraviolet-aging and adsorbed pollutants on toxicological effects of polyvinyl chloride microplastics to zebrafish

Microplastics (MPs) undergo various aging processes and interact with diverse pollutants in the environment. In the present study, we investigated the influence of ultraviolet (UV) aging on the adsorption of organic pollutants by polyvinyl chloride microplastics (mPVC) and explored toxicity variations among pristine, aged, and pollutant-loaded mPVCs to zebrafish. Irradiation of UV for 30 d significantly changed the physiochemical properties of mPVC, leading to more oxygen-containing groups and free radicals (¹O₂, ·O₂^-, and ·OH) on mPVC surfaces. The aging process reduced the adsorption of mPVC against a hydrophobic compound chlorpyrifos (CPF) but enhanced the adsorption against a moderately hydrophilic compound erythromycin (ERY). Ingestion of CPF- and ERY-loaded mPVCs resulted in bioaccumulation of the two compounds in zebrafish, suggesting a carrier effect of mPVCs. In toxicity tests, the aged mPVC caused severer gut damages, stronger oxidative stresses, and greater interference with the gut microbiota in zebrafish than the pristine mPVC. The CPF and ERY-loaded mPVCs produced lower oxidative stresses in zebrafish than mPVCs alone, due to fewer radicals on mPVC surfaces after the adsorption of organic contaminants. Notably, the CPF and ERY-loaded mPVCs presented greater effects on fish swimming behaviors and gut microbial compositions, which was associated with the released CPF and ERY from mPVCs within the zebrafish. Overall, the present study demonstrated significant influences of UV-aging and the adsorbed pollutants on the toxicological effects of MPs and highlighted the necessity to perform toxicity studies of MPs using more environmentally relevant MPs.

Non-steroidal anti-inflammatory drugs caused an outbreak of inflammation and oxidative stress with changes in the gut microbiota in rainbow trout (Oncorhynchus mykiss)

One of the main contributors to pharmaceutical pollution of surface waters are non-steroidal anti-inflammatory drugs (NSAIDs) that contaminate the food chain and affect non-target water species. As there are not many studies focusing on toxic effects of NSAIDs on freshwater fish species and specially effects after dietary exposure, we selected rainbow trout (Oncorhynchus mykiss) as the ideal model to examine the impact of two NSAIDs - diclofenac (DCF) and ibuprofen (IBP). The aim of our study was to test toxicity of environmentally relevant concentrations of these drugs together with exposure doses of 100× higher, including their mixture; and to deepen knowledge about the mechanism of toxicity of these drugs. This study revealed kidneys as the most affected organ with hyalinosis, an increase in oxidative stress markers, and changes in gene expression of heat shock protein 70 to be signs of renal toxicity. Furthermore, hepatotoxicity was confirmed by histopathological analysis (i.e. dystrophy, congestion, and inflammatory cell increase), change in biochemical markers, increase in heat shock protein 70 mRNA, and by oxidative stress analysis. The gills were locally deformed and showed signs of inflammatory processes and necrotic areas. Given the increase in oxidative stress markers and heat shock protein 70 mRNA, severe impairment of oxygen transport may be one of the toxic pathways of NSAIDs. Regarding the microbiota, an overgrowth of Gram-positive species was detected; in particular, significant dysbiosis in the Fusobacteria/Firmicutes ratio was observed. In conclusion, the changes observed after dietary exposure to NSAIDs can influence the organism homeostasis, induce ROS production, potentiate inflammations, and cause gut dysbiosis. Even the environmentally relevant concentration of NSAIDs pose a risk to the aquatic ecosystem as it changed O. mykiss health parameters and we assume that the toxicity of NSAIDs manifests itself at the level of mitochondria and proteins.

Food and human safety: the impact of microplastics

Plastic waste pollution is one of the biggest problems in the world today. The amount of plastic in the environment continues to increase, and human exposure to microplastic (MP) has become a reality. This subject has attracted the attention of the whole world. The MP problem has also been noticed by the scientific community. The term microplastic is mostly used to define synthetic material with a high polymer content that can have a size range from 0.1 to 5000 µm. This paper aims to characterize the routes of exposure to MP, define its pollution sources, and identify food types contaminated with plastics. This review addresses the current state of knowledge on this type of particles, with particular emphasis on their influence on human health. Adverse effects of MP depend on routes and sources of exposure. The most common route of exposure is believed to be the gastrointestinal tract. Sources of MP include fish, shellfish, water as well as tea, beer, wine, energy drinks, soft drinks, milk, salt, sugar, honey, poultry meat, fruits, and vegetables. Studies have shown that particles of PET, PE, PP, PS, PVC, PA, and PC are the most frequently found in food.

Toxicity of tire wear particles and the leachates to microorganisms in marine sediments

Tire wear particles (TWPs), which are among the microplastic pollutants in the environment, can inevitably accumulate in coastal sediments. The present study comprehensively investigated the effect of pristine TWPs on bacterial community structure in coastal sediments and compared the effect of pristine TWPs and aged TWPs on nine strains of bacteria in sediments. In addition, the effect of the TWP leachate was studied with all the nine bacterial strains and the toxicity-causing substances in the leachate was investigated using Bacillus subtilis. Exposure to TWPs could lead to a shift in bacteria community and affect nitrogen metabolism in marine sediments. Aged TWPs were more toxic than pristine TWPs due to changes in particle surface characteristics. The leachate exhibited greater toxicity than TWPs as well, and Zn was identified to be the major toxicity-causing substance. The overall results of this study are important for understanding the effects of TWPs and the leachates on microorganisms in marine sediments.

T-cell receptor variable region usage in Chagas disease: A systematic review of experimental and human studies

T cells recognize their ligand, the peptide major histocompatibility complex (MHC), via the T-cell receptor (TCR), which is composed of covalently linked α and β or γ and δ chains. This recognition is critical for T-cell ontogeny and controls the selection, activation, and function of T lymphocytes. Specific TCR αβ variable regions have been associated with immunopathogenesis of Chagas disease. Here, we present a systematic review that compiles experimental in vivo and human data regarding the preferential expression of variable alpha (Vα) and variable beta (Vβ) chain regions in Trypanosoma cruzi infection. The original studies indexed in PubMed/Medline, Scopus, and Web of Science databases were screened according to the PRISMA strategy. The analysis showed that expression of TCR Vα subfamilies were evaluated in one human study, and, unlike TCR Vβ, TCR Vα presented a more restricted usage. Despite the great variability in the usage of TCR Vβ regions in human Chagas disease, a down-regulation of TCR Vβ5 expression by T cells from patients in the acute phase of the disease was shown. Opposingly, this TCR region was found overly expressed in CD4+ T cells from chronic Chagas patients. It was also demonstrated that murine Vβ9+ T cells derived from nonlymphoid organs of T. cruzi-infected animals had a modulatory profile, while splenic Vβ9+ T cells produced inflammatory cytokines, indicating that although they display the same TCR Vβ region usage, these cells are functionally distinct. Despite the limitations of few papers and year of publication of the studies, compiling the data derived from them reveals that further investigation of TCR usage will point to their potential role in protective or pathogenic responses, as biomarkers of disease progression, and in the search for dominant peptides potentially useful for the development of vaccines or therapies.

Chagas disease is a neglected tropical disease, caused by infection with Trypanosoma cruzi. Differential expression of certain T-cell receptor (TCR) variable regions has been associated with the immunopathogenesis of Chagas disease. Here, we present a systematic review that compiled experimental in vivo and human data regarding the preferential expression of TCR alpha and beta chain variable regions in Chagas disease. The original studies indexed in the PubMed/Medline, Scopus, and Web of Science databases were screened according to the PRISMA strategy. Despite the great variability in the use of TCR Vβ in T. cruzi infection, the outcomes indicate that there is a down-regulation of TCR Vβ5 expression in T cells from patients in the acute phase of Chagas disease. However, this region is preferentially expressed by CD4+ T cells from chronic Chagas patients. Additionally, it has been demonstrated that murine Vβ9+ T cells derived from nonlymphoid organs displayed a modulatory profile, while splenic Vβ9+ T cells produced inflammatory cytokines, indicating that although they express the same TCR Vβ region, these cells are functionally distinct. Information on TCR expression, specificity and function have critical impact on vaccine design.

Laboratory Plasticware Induces Expression of a Bacterial Virulence Factor

Pollution with microplastic has become a prime environmental concern. The various ways in which human-made polymers and microorganisms interact are little understood, and this is particularly true for microplastic and pathogenic microorganisms. Previous reports demonstrated that expression of central virulence-associated protein A (VapA) of the pathogenic bacterium Rhodococcus equi is shut off at 30°C, whereas it is strongly expressed at 37°C, a temperature which may serve as an intrahost cue. Here, we show that cultivation at 30°C in disposable plastic tubes increases mRNA levels of vapA 70-fold compared to growth in conventional glass tubes. Strong expression of vapA in plastic tubes does not seem to be caused by a compound leaching from plastic but rather by tube surface properties. Expression stimulation during growth in plastic is regulated by the R. equi transcription regulators VirR and VirS, indicating that plastic-induced vapA expression is (co)regulated through the canonical vapA expression pathway. Our observations have important implications for the future analysis and assessment of environmental microplastic contaminations in that they show that, in principle, contact of pathogens with environmental plastic can increase their virulence.

IMPORTANCE Millions of tons small plastic pieces (microplastic) find their way into the environment every year. They pose digestive and toxicity problems to various life forms in soil, freshwater, and seawater. Additionally, microplastic offers an opportunity for microorganisms to attach and to become an important part of a “plastisphere community.” The significance of our study lies in the documentation of a sharp increase in production of a central virulence factor by a bacterial pathogen when the bacterium is in touch with certain makes of plastic. Although this feature may not reflect an increased health risk in case of this particular soilborne pathogen, our data disclose a new facet of how microplastics can endanger life.