Deciphering Gut Microbiome Responses upon Microplastic Exposure via Integrating Metagenomics and Activity-Based Metabolomics

Exposure to polyethylene terephthalate micro(nano)plastics exacerbates inflammation and fibrosis after myocardial infarction by reprogramming the gut and lung microbiota and metabolome

Micro(nano)plastics (MNPs), a ubiquitous environmental pollutant, have received increasing attention for their impacts on human health. We conducted an in-depth study on the role of polyethylene terephthalate (PET) MNPs in myocardial infarction (MI). Blood from the coronary circulation of MI patients was collected to detect microplastics (MPs). Peripheral monocytes (PBMCs) and AC16 cells were used to assess inflammation, cell proliferation and apoptosis after PET nanoplastics (NPs) stimulation. The mouse MI model was established after PET NPs respiratory or oral exposure. The results showed that various types of MPs, including high levels of PET MPs, were detected in the coronary circulation. PET NPs promoted inflammatory factors secretion by PBMCs, inhibited AC16 cell proliferation and promoted hypoxia-induced AC16 cell apoptosis. PET NPs exacerbated post-MI inflammation and fibrosis through activating the NLRP3 inflammasome pathway. Through macrogenetic sequencing and metabolomics analyses, we observed that PET NPs reprogrammed the intestinal and lung microbiota and metabolome in MI mice, leading to chronic inflammation. In conclusion, PET MPs were widely present in the coronary circulation of MI patients. PET MNPs can activate the NLRP3 inflammasome pathway to exacerbate post-MI ventricular remodelling, which may be related to the reprogramming of the gut and lung microbiota and metabolome.

Commonly prescribed multi-medication therapies exert sex-specific effects on Alzheimer's disease pathology and metabolomic profiles in AppNL-G-F mice: Implications for personalized therapeutics in aging

INTRODUCTION

Polypharmacy is common among older adults and people with dementia. Multi-medication therapy poses risks of harm but also targets comorbidities and risk factors associated with dementia, offering therapeutic potential.

METHODS

We evaluated the effects of two polypharmacy regimens and monotherapies on male and female AppNL-G-F knock-in mice. We assessed functional, emotional, and cognitive outcomes;amyloid pathology; and serum metabolomics profiles.

RESULTS

A combination of metoprolol, simvastatin, aspirin, paracetamol, and citalopram improved memory, reduced amyloid burden and neuroinflammation, and modulated AD-associated metabolomic signatures in male mice, with negligible effects in female mice. Substituting two cardiovascular drugs impacted emotional domains but worsened memory, predominantly in female mice. In males, monotherapies could not explain the combination effects, suggesting drug synergy, whereas in female mice, certain monotherapy effects were lost when combined.

DISCUSSION

This study uncovers the sex-specific effects of polypharmacy in an AD model, identifying mechanisms and biomarkers that can guide gender-specific use of medicines in dementia prevention and management.

HIGHLIGHTS

Two polypharmacy combinations show sex-specific effects on AD pathology and serum metabolomic profiles. Metoprolol+simvastatin+aspirin+paracetamol+citalopram improves memory and amyloid pathology in male mice. Replacing metoprolol and simvastatin with enalapril and atorvastatin eliminates benefits in male mice and impairs memory in female mice. Selected monotherapies produce sex-specific effects but only partially explain the outcomes of the combinations. Metabolomic pathways in serum indicate possible mechanisms and biomarkers for evaluating the effectiveness and safety of personalized therapies in aging and dementia.

Combined metabolomics and 16S rDNA sequence analyses of the gut microbiome reveal the action mechanism of Fructus Akebiae against hepatic fibrosis

Objectives

To explore the mechanism underlying the effect of Fructus Akebiae (FAE) against hepatic fibrosis in mice through combined network pharmacology, liver metabolomics, and 16S rDNA analyses of the gut microbiota.

Methods

In this study, we randomly divided mice into the control, model, FAE high-dose, FAE medium-dose, and FAE low-dose groups to analyze the pathological changes in the hepatic fibrosis and levels of the α-SMA, collagen 1, Nuclear Factor Kappa B (NF-κ B), Toll Like Receptor 4 (TLR4). The gut microbiota was analyzed through 16S rDNA sequencing analysis of liver metabolites using liquid chromatography-mass spectrometry. Furthermore, network pharmacology was used to determine the specific molecular regulation mechanism of FAE in hepatic fibrosis treatment.

Results

FAE treatment markedly improved the pathological changes in the hepatic fibrosis. Analysis revealed that FAE administration reversed the carbon tetrachloride (CCl4)-induced dysbiosis by increasing the abundance of Akkermansia and reducing that of Cyanobacteria. Additionally, metabolomic analysis showed that FAE treatment reversed the CCl4-induced metabolic disorders by regulating amino and nucleotide sugar metabolism. Furthermore, correlation analysis showed that Akkermansia and Verrucomicobiota were closely related to D-tolasaccharide and maltotetraose saccharide. Moreover, network pharmacology indicated that FAE might regulate the signaling pathway through the JUN/CASP3/NOS3/PTGS2/HSP90AA1 during treatment.

Conclusion

FAE may be a promising treatment for hepatic fibrosis, and its protective effects are associated with improvements in the microbiome and metabolic disorders.

Mechanisms underlying Th2-dominant pneumonia caused by plastic pollution derivatives (PPD): A molecular toxicology investigation that encompasses gut microbiomics and lung metabolomics

An investigation was conducted by researchers on how dibutyl phthalate (DBP) and polystyrene microplastics (PS-MP) influence the development of pneumonia using a mouse model. For a duration of five weeks, the mice were subjected to exposure of DBP (30 mg/kg/day) and PS-MP (0.1 mg/day). The findings indicated notable pathological alterations in airway tissues, increased oxidative stress levels, and intensified inflammation, thereby establishing a connection between plastic pollution and pneumonia. Further examination indicated the involvement of ferroptosis and oxidative stress in the progression of the disease. Administration of deferoxamine (DFO) (100 mg/kg) resulted in symptom relief and reduced pathological alterations, as validated by metabolomic investigations. Increased levels of reactive oxygen species (ROS) triggered a Th2-mediated eosinophilic inflammatory response, marked by elevated IL-4 and reduced IFN-γ via the NFκB pathway. Moreover, analyses of the gut microbiome and metabolomics demonstrated that PPD modifies microbial populations and pulmonary metabolism, linking its effects on pneumonia through the gut-lung axis. This research highlights the health hazards associated with plastic pollution and proposes a framework for tackling these issues.

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.

Assessment and accumulation of microplastics in the Indian riverine systems: Risk assessment and implications of translocation across the water-to-fish continuum

Microplastic (MP) pollution has engulfed global aquatic systems, and the concerns about microplastic translocation and bioaccumulation in fish and other aquatic organisms are now an unpleasant truth. In the past few years, MP pollution in freshwater systems, particularly rivers and subsequently in freshwater organisms, especially in fish, has caught the attention of researchers. Rivers provide livelihood to approximately 40 % of the global population through food and potable water. Hence, assessment of emerging contaminants like microplastics in rivers and the associated fauna is crucial. This study assessed microplastics (MPs) in fish, sediment and freshwater samples across the third largest riverine system of peninsular India, the Mahanadi River. The number concentrations of MPs measured in water, sediment and fish ranged from 337.5 ± 54.4-1333.3 ± 557.2 MPs/m3, 14.7 ± 3.7-69.3 ± 10.1 MPs/kg. Dry weight and 0.4-3.2 MPs/Fish, respectively. Surprisingly, MPs were found in every second fish sample, with a higher MP number in the gut than in the gills. Black and blue coloured filaments with <0.5 mm size were the dominant MPs with polypropylene and polyethylene polymers in abundance. The Polymer Hazard Index (PHI) and the Potential Ecological Risk Index (PERI) studies revealed that the majority of the sampling sites fell in Risk category V (dangerous category). An irregular trend in the MP concentration was observed downstream of the river, though relatively elevated MP concentrations in water and fish samples were observed downstream of the river. t-Distributed Stochastic Neighbour Embedding (t-SNE) unveiled distinct patterns in MP distribution with a higher similarity exhibited in the MPs found in fish gill and gut samples, unlike water and sediment, which shared certain characteristics. The findings in the current study contribute to filling the knowledge gap of MP assessment and accumulation in global freshwater systems and highlight the microplastic contamination and accumulation in fish with its potential implications on human health.

The impact of microplastics polystyrene on the microscopic structure of mouse intestine, tight junction genes and gut microbiota

Microplastics, which are tiny plastic particles less than 5 mm in diameter, are widely present in the environment, have become a serious threat to aquatic life and human health, potentially causing ecosystem disorders and health problems. The present study aimed to investigate the effects of microplastics, specifically microplastics-polystyrene (MPs-PS), on the structural integrity, gene expression related to tight junctions, and gut microbiota in mice. A total of 24 Kunming mice aged 30 days were randomly assigned into four groups: control male (CM), control female (CF), PS-exposed male (PSM), and PS-exposed female (PSF)(n = 6). There were significant differences in villus height, width, intestinal surface area, and villus height to crypt depth ratio (V/C) between the PS group and the control group(C) (p <0.05). Gene expression analysis demonstrated the downregulation of Claudin-1, Claudin-2, Claudin-15, and Occludin, in both duodenum and jejunum of the PS group (p < 0.05). Analysis of microbial species using 16S rRNA sequencing indicated decreased diversity in the PSF group, as well as reduced diversity in the PSM group at various taxonomic levels. Beta diversity analysis showed a significant difference in gut microbiota distribution between the PS-exposed and C groups (R2 = 0.113, p<0.01), with this difference being more pronounced among females exposed to MPs-PS. KEGG analysis revealed enrichment of differential microbiota mainly involved in seven signaling pathways, such as nucleotide metabolism(p<0.05). The relative abundance ratio of transcriptional pathways was significantly increased for the PSF group (p<0.01), while excretory system pathways were for PSM group(p<0.05). Overall findings suggest that MPs-PS exhibit a notable sex-dependent impact on mouse gut microbiota, with a stronger effect observed among females; reduced expression of tight junction genes may be associated with dysbiosis, particularly elevated levels of Prevotellaceae.

Associations of Plastic Bottle Exposure with Infant Growth, Fecal Microbiota, and Short-Chain Fatty Acids

BACKGROUND/OBJECTIVES

Murine models show that plastics, via their chemical constituents (e.g., phthalates), influence microbiota, metabolism, and growth. However, research on plastics in humans is lacking. Here, we examine how the frequency of plastic bottle exposure is associated with fecal microbiota, short-chain fatty acids (SCFAs), and anthropometry in the first year of life.

SUBJECTS/METHODS

In 442 infants from the prospective Nurture birth cohort, we examined the association of frequency of plastic bottle feeding at 3 months with anthropometric outcomes (skinfolds, length-for-age, and weight-for-length) at 12 months of age and growth trajectories between 3 and 12 months. Furthermore, in a subset of infants (n = 70) that contributed fecal samples at 3 months and 12 months of age, we examined plastic bottle frequency in relation to fecal microbiota composition and diversity (measured by 16S rRNA gene sequencing of V4 region), and fecal SCFA concentrations (quantified using gas chromatography mass spectrometry).

RESULTS

At 3 months, 67.6% of infants were plastic bottle fed at every feeding, 15.4% were exclusively breast milk fed, and 48.9% were exclusively formula fed. After adjustment for potential confounders, infants who were plastic bottle fed less than every feeding compared to those who were plastic bottle fed at every feeding at 3 months did not show differences in anthropometry over the first 12 months of life, save for lower length-for-age z-score at 12 months (adjusted β = -0.45, 95% CI: -0.76, -0.13). Infants who were plastic bottle fed less than every feeding versus every feeding had lower fecal microbiota alpha diversity at 3 months (mean difference for Shannon index: -0.59, 95% CI: -0.99, -0.20) and lower isovaleric acid concentration at 3 months (mean difference: -2.12 μmol/g, 95% CI: -3.64, -0.60), but these results were attenuated following adjustment for infant diet. Plastic bottle frequency was not strongly associated with microbiota diversity or SCFAs at 12 months after multivariable adjustment. Frequency of plastic bottle use was associated with differential abundance of some bacterial taxa, however, significance was not consistent between statistical approaches.

CONCLUSIONS

Plastic bottle frequency at 3 months was not strongly associated with measures of adiposity or growth (save for length-for-age) over the first year of life, and while plastic bottle use was associated with some features of fecal microbiota and SCFAs in the first year, these findings were attenuated in multivariable models with infant diet. Future research is needed to assess health effects of exposure to other plastic-based products and objective measures of microplastics and plastic constituents like phthalates.

In Vivo Tissue Distribution of Microplastics and Systemic Metabolomic Alterations After Gastrointestinal Exposure

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. To investigate the impact of ingested MPs on target metabolomic pathways, mice were subjected to either polystyrene microspheres or a mixed plastics (5 µm) exposure consisting of polystyrene, polyethylene and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid). Exposures were performed twice a week for four weeks at a dose of either 0, 2, or 4 mg/week via oral gastric gavage. Our findings demonstrate that, in mice, ingested MPs can pass through the gut barrier, be translocated through the systemic circulation, and accumulate in distant tissues including the brain, liver, and kidney. Additionally, we report on the metabolomic changes that occur in the colon, liver and brain which show differential responses that are dependent on dose and type of MPs exposure. Lastly, our study provides proof of concept for identifying metabolomic alterations associated with MPs exposure and adds insight into the potential health risks that mixed MPs contamination may pose to humans.