Polystyrene microplastics significantly facilitate influenza A virus infection of host cells

Plastisphere-hosted viruses: A review of interactions, behavior, and effects

Microbial communities, including bacteria, diatoms, and fungi, colonize plastic surfaces, forming biofilms known as the "plastisphere." Recent research has revealed that plastispheres also host a wide range of viruses, sparking interest in microbial ecology and virology. This shared habitat allows viruses to replicate, interact, infect, and spread, potentially impacting the environment and human health. Consequently, viruses attached to microplastics are now recognized to have broad effects on cellular and immune responses. However, the ecology and implications of viruses hosted in plastisphere habitats remain poorly understood, highlighting their fundamental importance as a subject of study. This review explores various pathways for virus attachment to plastispheres, factors influencing these interactions, their impacts within plastisphere and host-associated environments, and associated issues. It also summarizes current research and identifies knowledge gaps. We anticipate that this paper will help improve our predictive understanding of plastisphere viruses in natural settings and emphasizes the need for more research in real-world environments to advance the field.

Immunotoxicity of microplastics in fish

Plastic waste degrades slowly in aquatic environments, transforming into microplastics (MPs) and nanoplastics (NPs), which are subsequently ingested by fish and other aquatic organisms, causing both physical blockages and chemical toxicity. The fish immune system serves as a crucial defense against viruses and pollutants present in water. It is imperative to comprehend the detrimental effects of MPs on the fish immune system and conduct further research on immunological assessments. In this paper, the immune response and immunotoxicity of MPs and its combination with environmental pollutants on fish were reviewed. MPs not only inflict physical harm on the natural defense barriers like fish gills and vital immune organs such as the liver and intestinal tract but also penetrate cells, disrupting intracellular signaling pathways, altering the levels of immune cytokines and gene expression, perturbing immune homeostasis, and ultimately compromising specific immunity. Initially, fish exposed to MPs recruit a significant number of macrophages and T cells while activating lysosomes. Over time, this exposure leads to apoptosis of immune cells, a decline in lysosomal degradation capacity, lysosomal activity, and complement levels. MPs possess a small specific surface area and can efficiently bind with heavy metals, organic pollutants, and viruses, enhancing immune responses. Hence, there is a need for comprehensive studies on the shape, size, additives released from MPs, along with their immunotoxic effects and mechanisms in conjunction with other pollutants and viruses. These studies aim to solidify existing knowledge and delineate future research directions concerning the immunotoxicity of MPs on fish, which has implications for human health.

Microplastics in the human body: A comprehensive review of exposure, distribution, migration mechanisms, and toxicity

Microplastics (MPs) are pervasive across ecosystems, presenting substantial risks to human health. Developing a comprehensive review of MPs is crucial due to the growing evidence of their widespread presence and potential harmful effects. Despite the growth in research, considerable uncertainties persist regarding their transport dynamics, prevalence, toxicological impacts, and the potential long-term health effects they may cause. This review thoroughly evaluates recent advancements in research on MPs and their implications for human health, including estimations of human exposure through ingestion, inhalation, and skin contact. It also quantifies the distribution and accumulation of MPs in various organs and tissues. The review discusses the mechanisms enabling MPs to cross biological barriers and the role of particle size in their translocation. To ensure methodological rigor, this review adheres to the PRISMA guidelines, explicitly detailing the literature search strategy, inclusion criteria, and the quality assessment of selected studies. The review concludes that MPs pose significant toxicological risks, identifies critical gaps in current knowledge, and recommends future research directions to elucidate the prolonged effects of MPs on human health. This work aims to offer a scientific framework for mitigating MP-related hazards and establishes a foundation for ongoing investigation.

A review of the influence of environmental pollutants (microplastics, pesticides, antibiotics, air pollutants, viruses, bacteria) on animal viruses

Microorganisms, especially viruses, cause disease in both humans and animals. Environmental chemical pollutants including microplastics, pesticides, antibiotics sand air pollutants arisen from human activities affect both animal and human health. This review assesses the impact of chemical and biological contaminants (virus and bacteria) on viruses including its life cycle, survival, mutations, loads and titers, shedding, transmission, infection, re-assortment, interference, abundance, viral transfer between cells, and the susceptibility of the host to viruses. It summarizes the sources of environmental contaminants, interactions between contaminants and viruses, and methods used to mitigate such interactions. Overall, this review provides a perspective of environmentally co-occurring contaminants on animal viruses that would be useful for future research on virus-animal-human-ecosystem harmony studies to safeguard human and animal health.

Effect of polypropylene microplastics on virus resistance in spotted sea bass (Lateolabrax maculatus)

Microplastics (MPs) pollution is a hot issue of global concern. Polypropylene microplastics (PP-MPs) age quickly in the marine environment and break down into smaller particles because of their relatively low temperature resistance, poor ultraviolet resistance, and poor antioxidant capacity, making them one of the major pollutants in the ocean. We assessed whether long-term exposure to micron-sized PP-MPs influences fish susceptibility to viral diseases. We found that exposure to PP-MPs (1-6 μm and 10-30 μm) at concentrations of 500 and 5000 μg/L resulted in uptake into spleen and kidney tissues of Lateolabrax maculatus. Increased activation of melanomacrophage centers was visible in histopathological sections of spleen from fish exposed to PP-MPs, and greater deterioration was observed in the spleen of fish infected by largemouth bass ulcerative syndrome virus after PP-MPs exposure. Additionally, exposure to PP-MPs led to significant cytotoxicity and a negative impact on the antiviral ability of cells. PP-MPs exposure had inhibitory or toxic effects on the immune system in spotted sea bass, which accelerated virus replication in vivo and decreased the expression of the innate immune- and acquired immune related genes in spleen and kidney tissues, thus increasing fish susceptibility to viral diseases. These results indicate that the long-term presence of micron-sized PP-MPs might impact fish resistance to disease, thereby posing a far-reaching problem for marine organisms.

Dietary exposure to polystyrene microplastics exacerbates liver damage in fulminant hepatic failure via ROS production and neutrophil extracellular trap formation

With the increasing influx of microplastics (MPs) into the environment, their potential toxicity represents an increasing threat to human health. However, there is a lack of relevant research surrounding the biological toxicity associated with pre-exposure to MPs under pathological conditions. To fill this gap, we established a mouse model of fulminant hepatic failure after 14 days of pre-exposure to polystyrene (PS) MPs and investigated its biological response process under combined stimulation with lipopolysaccharide (LPS)/d-galactosamine (d-GalN) and PS-MPs. The results indicated that the stress response from exposure to PS-MPs exacerbated the death induced by LPS/d-GalN and reinforced the potential of liver damage in mice. The dominant roles of inflammation promotion, reactive oxygen species (ROS), and neutrophil extracellular traps in this process were confirmed by cellular reactive oxygen species assays and experiments on oxidative stress and inflammatory responses in the liver. Transcriptomic analysis revealed that PS-MPs exacerbated the expression levels of neutrophil extracellular traps in mice treated with LPS/d-GalN, and weakened the expression of genes involved in pathways related to peroxisome, taurine, and hypotaurine metabolism, which was further validated by reverse-transcription quantitative polymerase chain reaction. This study addresses the knowledge gap regarding the adverse effects caused by a pathological state upon exposure to MPs and provides a theoretical reference for further assessment of the underlying health risks of MPs.

Exposure to phagolysosomal simulated fluid altered the cytotoxicity of PET micro(nano)plastics to human lung epithelial cells

The occurrence of micro(nano)plastics into various environmental and biological settings influences their physicochemical and toxic behavior. Simulated body fluids are appropriate media for understanding the degradation, stability, and interaction with other substances of any material in the human body. When the particles enter the human body via inhalation, which is one of the avenues for micro(nano)plastics, they first come into contact with the lung lining fluid under neutral conditions and then are phagocytosed under acidic conditions to be removed. Therefore, it is important to examine the physicochemical transformation and toxicity characteristics after interaction with phagolysosomal simulant fluid (PSF). Here, we focused on exploring how the physicochemical differences (e.g. surface chemistry, elemental distribution, and surface charge) of micro(nano)plastics under pH 4.5 phagolysosome conditions impact cytotoxicity and the oxidative characteristics of lung epithelia cells. The cytotoxicity of lung epithelia cells to those treated with PSF and non-treated micro(nano)plastics was tested by various viability indicators including cell counting kit-8 (CCK-8), MTT, and LDH. Furthermore, the cytotoxicity background was examined through the oxidative processes (e.g. reactive oxygen species, antioxidant, superoxide dismutase (SOD), catalase, and reduced glutathione). The results showed that all tested surface physicochemical characteristics were significantly influenced by the phagolysosome conditions. The staged responses were observed with the treatment duration, and significant changes were calculated in carbonyl, carbon-nitrogen, and sulfonyl groups. Moreover, the negativity of the zeta potentials declined between exposure of 2-40 h and then increased at 80 h compared to control owing to the chemical functional groups and elemental distribution of the plastic particles. The tested viability indicators showed that the micro(nano)plastics treated with PSF were cytotoxic to the lung epithelia cells compared to non-treated micro(nano)plastics, and SOD was the dominant enzyme triggering cytotoxicity due to the particle degradation and instability.

Polystyrene Microplastics Exacerbate Candida albicans Infection Ability In Vitro and In Vivo

Plastic pollution is an important environmental problem, and microplastics have been shown to have harmful effects on human and animal health, affecting immune and metabolic physiological functions. Further, microplastics can interfere with commensal microorganisms and exert deleterious effects on exposure to pathogens. Here, we compared the effects of 1 µm diameter polystyrene microplastic (PSMPs) on Candida albicans infection in both in vitro and in vivo models by using HT29 cells and Galleria mellonella larvae, respectively. The results demonstrated that PSMPs could promote Candida infection in HT29 cells and larvae of G. mellonella, which show immune responses similar to vertebrates. In this study, we provide new experimental evidence for the risk to human health posed by PSMPs in conjunction with Candida infections.

Airborne microplastics: A narrative review of potential effects on the human respiratory system

There has been growing evidence showing the widespread of airborne microplastics (AMPs) in many regions of the world, raising concerns about their impact on human health. This review aimed to consolidate recent literature on AMPs regarding their physical and chemical characteristics, deposition in the human respiratory tract, translocation, occurrence from human studies, and toxic effects determined in vitro and in vivo. The physical characteristics influence interactions with cell membranes, cellular internalization, accumulation, and cytotoxicity resulting from cell membrane damage and oxidative stress. In addition, prolonged exposure to AMP-associated toxic chemicals might lead to significant health effects. Most toxicological assessments of AMPs in vitro and in vivo have demonstrated that oxidative stress and inflammation are major mechanisms of action for their toxic effects. Elevated reactive oxygen species production could lead to mitochondrial dysfunction, inflammatory responses, and subsequent apoptosis in experimental models. To date, there has been some evidence suggesting exposure in humans. However, the data are still insufficient, and adverse human health effects need to be investigated. Future research on the existence, exposure, and health effects of AMPs is required for developing preventive and mitigation measures to protect human health.

Deciphering the role of polystyrene microplastics in waste activated sludge anaerobic digestion: Changes of organics transformation, microbial community and metabolic pathway

Microplastics are ubiquitous in the natural environment, which inevitably affect the relevant biochemical process. Nevertheless, the knowledge about the impacts of microplastics on organics transformation and corresponding microbial metabolism response in anaerobic environment is limited. Here, polystyrene (PS) microplastics were selected as model microplastics to explore their potential impacts on organics transformation, microbial community and metabolic pathway during sludge anaerobic digestion system operation. The results indicated that the PS microplastics exhibited the dose-dependent effects on methane production, i.e., the additive of 20-40 particles/g TS of PS microplastics improved the maximum methane yield by 3.38 %-8.22 %, whereas 80-160 particles/g TS additive led to a 4.78 %-11.04 % declining. Overall, PS microplastics facilitated the solubilization and hydrolysis of sludge, but inhibited the acidogenesis process. Key functional enzyme activities were stimulated under low PS microplastics exposure, whereas were almost severely inhibited due to the increased oxidative stress induced from excess PS microplastics. Microbial community and further metabolic analysis indicated that low PS microplastics improved the acetotrophic and hydrogenotrophic methanogenesis, while a high level of PS microplastics shifted methanogenesis from acetotrophic to hydrogenotrophic pathway. Further analysis showed that the reacted PS microplastics exhibited greater toxicity and ecological than the raw PS microplastics due to that they are more likely to adsorb contaminants. These findings revealed the dosage-dependent relationships between microplastics and organics transformation process in anaerobic environments, providing new insights for assessing the impact of PS microplastics on sludge anaerobic digestion.

Nasal lavage technique reveals regular inhalation exposure of microplastics, not associated from face mask use

During the COVID-19 pandemic, the use of face masks has been a worldwide primary protection measure to contain the spread of the virus. However, very little information is known about the possible inhalation of microplastics (MP) from wearing masks. This pilot study evaluates the presence of MP accumulated in nasal cavities through the nasal lavages technique. Six different commercial face masks were tested in 18 participants during five working days (8 h use/day). Eight different polymers (polystyrene, polyamide, poly(ethylene - propylene) diene monomer, polyester, polyethylene, polyvinylidene fluoride, polypropylene, and polyvinyl chloride) predominantly within the 20-300 µm size were detected in nasal lavages, with an average concentration of 28.3 ± 15.6 MP/5 mL nasal solution. Results demonstrate that MP in the nasal cavity are not associated to face mask use but rather to general exposure to airborne MP. We highlight the use of nasal lavages to evaluate human inhalation of MP and associate it to potential sources and risks.