Mucus: An Underestimated Gut Target for Environmental Pollutants and Food Additives

Structure-function relationship of the brown seaweed Undaria pinnatifida laminaran: Protein kinase C-mediated mucus secretion and gut barrier restoration

Ulcerative colitis is a chronic inflammatory condition of the intestine characterized by mucosal damage and a compromised epithelial barrier. This study explored the protective and therapeutic potential of laminaran derived from the brown seaweed Undaria pinnatifida in promoting mucin secretion and restoring mucosal barrier integrity. Physicochemical analysis revealed laminaran as having a β-(1 → 3)-linked glucose backbone with β-(1 → 6)-linked branches and a molecular weight of 14.41 kDa. In vitro experiments revealed that laminaran enhanced the expression of mucin-related proteins in a lipopolysaccharide-induced LS174T model. Laminaran also upregulated the expression of sulfotransferases, which are essential for mucin sulfation, and promoted vesicular transport by increasing the expression of vesicle-associated membrane protein 8 and synaptosome-associated protein-23, facilitating mucin secretion. These effects are mediated through the protein kinase C (PKC) pathway, which involves PKCα and PKCβII. In an in vivo model, laminaran alleviated dextran sulfate sodium-induced colitis, increasing mucus thickness and overall intestinal barrier function. These results suggest that laminaran is a promising therapeutic agent for treating ulcerative colitis, suggesting a novel approach to restoring the mucosal barrier and reducing intestinal inflammation. This study lays the groundwork for developing laminaran-based treatments for ulcerative colitis and other intestinal diseases associated with epithelial barrier dysfunction.

A Bioengineered Model of the Human Cornea for Preclinical Assessment of Human Ocular Exposure to Environmental Toxicants

Here a bioengineered platform is introduced to investigate adverse effects of environmental materials on the human cornea. Using primary cells, this system is capable of reproducing the differentiated corneal epithelium and its underlying stroma in the human eye, which can then be treated with externally applied solid, liquid, or gaseous substances in a controlled manner and under physiologically relevant conditions. The proof-of-principle of how this system can be used to simulate human ocular exposure to different classes of environmental toxicants for direct visualization and quantitative analysis of their potential to induce acute corneal injury and inflammation is demonstrated. This model can also be further engineered to create an electromechanically actuated array of multiple human corneal tissues that can emulate spontaneous eye blinking. Using this advanced system, it is shown that blinking-like mechanical motions may play a protective role against adverse effects of environmental toxicants. This work yields an immediately deployable in vitro technology for screening ocular toxicity of existing and emerging environmental materials of various types and may enable the development of more realistic, human-relevant preclinical toxicology models complementary to traditional animal testing.

Effects of POPs-induced SIRT6 alteration on intestinal mucosal barrier function: A comprehensive review

Persistent organic pollutants (POPs) are pervasive organic chemicals with significant environmental and ecological ramifications, extending to adverse human health effects due to their toxicity and persistence. The intestinal mucosal barrier, a sophisticated defense mechanism comprising the epithelial layer, mucosal chemistry, and cellular immunity, shields the host from external threats and fosters a symbiotic relationship with intestinal bacteria. Sirtuin 6 (SIRT6), a sirtuin family member, is pivotal in genome and telomere stability, inflammation regulation, and metabolic processes. Result shows POPs have been implicated in the intestinal diseases, particularly in intestinal barrier dysfunction, through mechanisms such as cellular damage, epigenetic alterations, inflammation, microbiota changes, and metabolic disruptions. While the impact of SIRT6 expression changes on intestinal barrier functions has been reviewed, the mechanisms linking POPs to SIRT6 remain elusive. This review summarized the latest research results on the effects of POPs on intestinal barrier, discussed the role of SIRT6 from multiple mechanism perspectives, proposed new research directions on POPs, SIRT6 and intestinal health, and explored the therapeutic potential of SIRT6.

Health effects of synthetic additives and the substitution potential of plant-based additives

The growth of the world population and the rapid industrialization of food have led to food producers' increased reliance on food additives. While food additives offer numerous conveniences and advantages in food applications, the potential risks associated with synthetic additives remain a significant concern. This report examines the current status of safety assessment and toxicity studies of common synthetic additives, including flavorings (sweeteners and flavor enhancers), colorants, preservatives (antimicrobials and antioxidants), and emulsifiers. The report also examines recent advances in promising plant-based alternative additives in terms of active ingredients, sensory properties, potential health benefits, food application challenges, and their related technologies (edible coatings/films and nanoencapsulation technologies), providing valuable references and insights for the sustainable development of food additives.

Grape seed oil attenuates sodium arsenite-induced gastric, hepatic and colonic damage in Wistar rats

Arsenic exposure is associated with numerous morbidities due to dysfunction of various organ systems including the gastrointestinal tract. We investigated the protective effect of grape seed oil (GSO) against sodium arsenite (NaAsO2)-induced gastric, hepatic and colonic injuries in rats. Twenty-four male Wistar rats were divided into four groups of six as follows: Group A (control) received saline; group B received NaAsO2 (2.5 mg/kg) orally for 7 days; group C were treated concurrently with NaAsO2 and GSO (2 ml/kg), while group D received only GSO. Administration of NaAsO2 induced significant (p < 0.05) increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST); increased periodic acid Schiff (PAS) staining for mucus and increased goblet cell numbers in the stomach and colon; inflammatory cell infiltration and vascular congestion and alterations in the fecal bacterial flora. GSO supplementation generally promoted a reversal of changes induced by NaAsO2 towards control levels. Additionally, there was increased immunohistochemically detected expression of colonic B-cell lymphoma-1 (Bcl-2) and cytokeratins AE1/AE3, but reduced expression of mucin 1 (MUC1) and carcinoembryonic antigen (CEA) in NaAsO2 + GSO and GSO treated rats when compared with the NaAsO2 group. These results suggest that GSO promoted anti-inflammatory processes in the liver, stomach and colon, as well as opposing apoptosis in the colon, resulting in significant attenuation of damage to these tissues.

The influence of pre- and postnatal exposure to air pollution and green spaces on infant's gut microbiota: Results from the MAMI birth cohort study

BACKGROUND

Animal and human studies indicate that exposure to air pollution and natural environments might modulate the gut microbiota, but epidemiological evidence is very scarce.

OBJECTIVES

To assess the potential impact of pre- and postnatal exposure to air pollution and green spaces on infant gut microbiota assembly and trajectories during the first year of life.

METHODS

MAMI ("MAternal MIcrobes") birth cohort (Valencia, Spain, N = 162) was used to study the impact of environmental exposure (acute and chronic) on infant gut microbiota during the first year of life (amplicon-based 16S rRNA sequencing). At 7 days and at 1, 6 and 12 months, residential pre- and postnatal exposure to air pollutants (NO2, black carbon -BC-, PM2.5 and O3) and green spaces indicators (NDVI and area of green spaces at 300, 500 and 1000 m buffers) were obtained. For the association between exposures and alpha diversity indicators linear regression models (cross-sectional analyses) and mixed models, including individual as a random effect (longitudinal analyses), were applied. For the differential taxon analysis, the ANCOM-BC package with a log count transformation and multiple-testing corrections were used.

RESULTS

Acute exposure in the first week of life and chronic postnatal exposure to NO2 were associated with a reduction in microbial alpha diversity, while the effects of green space exposure were not evident. Acute and chronic (prenatal or postnatal) exposure to NO2 resulted in increased abundance of Haemophilus, Akkermansia, Alistipes, Eggerthella, and Tyzerella populations, while increasing green space exposure associated with increased Negativicoccus, Senegalimassilia and Anaerococcus and decreased Tyzzerella and Lachnoclostridium populations.

DISCUSSION

We observed a decrease in the diversity of the gut microbiota and signs of alteration in its composition among infants exposed to higher levels of NO2. Increasing green space exposure was also associated with changes in gut microbial composition. Further research is needed to confirm these findings.

Pyroptosis: a new insight into intestinal inflammation and cancer

Pyroptosis is an innate immune response triggered by the activation of inflammasomes by various influencing factors, characterized by cell destruction. It impacts the immune system and cancer immunotherapy. In recent years, the roles of pyroptosis and inflammasomes in intestinal inflammation and cancer have been continuously confirmed. This article reviews the latest progress in pyroptosis mechanisms, new discoveries of inflammasomes, mutual regulation between inflammasomes, and their applications in intestinal diseases. Additionally, potential synergistic treatment mechanisms of intestinal diseases with pyroptosis are summarized, and challenges and future directions are discussed, providing new ideas for pyroptosis therapy.

Impact of Chronic Exposure to Arsenate through Drinking Water on the Intestinal Barrier

Chronic exposure to inorganic arsenic (As) [As(III) + As(V)], which affects millions of people, increases the incidence of some kinds of cancer and other noncarcinogenic pathologies. Although the oral pathway is the main source of exposure, in vivo studies conducted to verify the intestinal toxicity of this metalloid are scarce and are mainly focused on evaluating the toxicity of As(III). The aim of this study was to evaluate the effect of chronic exposure (6 months) of BALB/c mice to As(V) (15-60 mg/L) via drinking water on the different components of the intestinal barrier and to determine the possible mechanisms involved. The results show that chronic exposure to As(V) generates a situation of oxidative stress (increased lipid peroxidation and reactive species) and inflammation (increased contents of several proinflammatory cytokines and neutrophil infiltrations) in the intestinal tissues. There is also evidence of an altered expression of constituent proteins of the intercellular junctions (Cldn1, Cldn3, and Ocln) and the mucus layer (Muc2) and changes in the composition of the gut microbiota and the metabolism of short-chain fatty acids. All of these toxic effects eventually may lead to the disruption of the intestinal barrier, which shows an increased paracellular permeability. Moreover, signs of endotoxemia are observed in the serum of As(V)-treated animals (increases in lipopolysaccharide-binding protein LBP and the proinflammatory cytokine IL-1β). The data obtained suggest that chronic exposure to As(V) via drinking water affects the intestinal environment.

The interaction between intestinal microenvironment and stroke

BACKGROUND

Stroke is not only a major cause of disability but also the third leading cause of death, following heart disease and cancer. It has been established that stroke causes permanent disability in 80% of survivors. However, current treatment options for this patient population are limited. Inflammation and immune response are major features that are well-recognized to occur after a stroke. The gastrointestinal tract hosts complex microbial communities, the largest pool of immune cells, and forms a bidirectional regulation brain-gut axis with the brain. Recent experimental and clinical studies have highlighted the importance of the relationship between the intestinal microenvironment and stroke. Over the years, the influence of the intestine on stroke has emerged as an important and dynamic research direction in biology and medicine.

AIMS

In this review, we describe the structure and function of the intestinal microenvironment and highlight its cross-talk relationship with stroke. In addition, we discuss potential strategies aiming to target the intestinal microenvironment during stroke treatment.

CONCLUSION

The structure and function of the intestinal environment can influence neurological function and cerebral ischemic outcome. Improving the intestinal microenvironment by targeting the gut microbiota may be a new direction in treating stroke.

Copper-mediated shifts in transcriptomic responses of intestines in Bufo gargarizans tadpoles to lead stress

The differential transcriptomic responses of intestines in Bufo gargarizans tadpoles to Pb alone or in the presence of Cu were evaluated. Tadpoles were exposed to 30 μg/L Pb individually and in combination with Cu at 16 or 64 μg/L from Gosner stage (Gs) 26 to Gs 38. After de novo assembly, 105,107 unigenes were generated. Compared to the control group, 7387, 6937, and 11139 differentially expressed genes (DEGs) were identified in the treatment of Pb + Cu0, Pb + Cu16, and Pb + Cu64, respectively. In addition, functional annotation and enrichment analysis of DEGs revealed substantial transcriptional reprogramming of diverse molecular and biological pathways were induced in all heavy metal treatments. The relative expression levels of genes associated with intestinal epithelial barrier and bile acids (BAs) metabolism, such as mucin2, claudin5, ZO-1, Asbt, and Ost-β, were validated by qPCR. This study demonstrated that Pb exposure induced transcriptional responses in tadpoles, and the responses could be modulated by Cu.

O-Mucin-degrading carbohydrate-active enzymes and their possible implication in inflammatory bowel diseases

Inflammatory bowel diseases (IBD) are modern diseases, with incidence rising around the world. They are associated with perturbation of the intestinal microbiota, and with alteration and crossing of the mucus barrier by the commensal bacteria that feed on it. In the process of mucus catabolism and invasion by gut bacteria, carbohydrate-active enzymes (CAZymes) play a critical role since mucus is mainly made up by O- and N-glycans. Moreover, the occurrence of IBD seems to be associated with low-fiber diets. Conversely, supplementation with oligosaccharides, such as human milk oligosaccharides (HMOs), which are structurally similar to intestinal mucins and could thus compete with them towards bacterial mucus-degrading CAZymes, has been suggested to prevent inflammation. In this mini-review, we will establish the current state of knowledge regarding the identification and characterization of mucus-degrading enzymes from both cultured and uncultured species of gut commensals and enteropathogens, with a particular focus on the present technological opportunities available to further the discovery of mucus-degrading CAZymes within the entire gut microbiome, by coupling microfluidics with metagenomics and culturomics. Finally, we will discuss the challenges to overcome to better assess how CAZymes targeting specific functional oligosaccharides could be involved in the modulation of the mucus-driven cross-talk between gut bacteria and their host in the context of IBD.

Regulation of Physiological Barrier Function by the Commensal Microbiota

A fundamental characteristic of living organisms is their ability to separate the internal and external environments, a function achieved in large part through the different physiological barrier systems and their component junctional molecules. Barrier integrity is subject to multiple influences, but one that has received comparatively little attention to date is the role of the commensal microbiota. These microbes, which represent approximately 50% of the cells in the human body, are increasingly recognized as powerful physiological modulators in other systems, but their role in regulating barrier function is only beginning to be addressed. Through comparison of the impact commensal microbes have on cell-cell junctions in three exemplar physiological barriers-the gut epithelium, the epidermis and the blood-brain barrier-this review will emphasize the important contribution microbes and microbe-derived mediators play in governing barrier function. By extension, this will highlight the critical homeostatic role of commensal microbes, as well as identifying the puzzles and opportunities arising from our steadily increasing knowledge of this aspect of physiology.

Improvement of the intestinal epithelial barrier during laxative effects of phlorotannin in loperamide-induced constipation of SD rats

BACKGROUND

Disruptions of the intestinal epithelial barrier (IEB) are frequently observed in various digestive diseases, including irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This study assessed the improvement in the IEB during the laxative activity of phlorotannin (Pt) harvested from Ecklonia cava in constipation by examining the changes in the expression of the regulatory proteins for the tight junction (TJ) and adherens junction (AJ), and inflammatory cytokines in Sprague Dawley (SD) rats with loperamide (Lm)-induced constipation after a Pt treatment.

RESULTS

The Pt treatment induced laxative activity, including the improvement of feces-related parameters, gastrointestinal transit rate, and histological structure of the mid colon in Lm-treated SD rats. In addition, significant recovery effects were detected in the histology of IEB, including the mucus layer, epithelial cells, and lamina propria in the mid colon of Lm + Pt treated SD rats. The expression levels of E-cadherin and p120-catenin for AJ and the ZO-1, occludin, and Claudin-1 genes for TJ in epithelial cells were improved remarkably after the Pt treatment, but the rate of increase was different. Furthermore, the Pt treatment increased the expression level of several inflammatory cytokines, such as TNF-α, IL-6, IL-1β, IL-13, and IL-4 in Lm + Pt treated SD rats.

CONCLUSIONS

These results provide the first evidence that the laxative activity of Pt in SD rats with Lm-induced constipation phenotypes involve improvements in the IEB.

Pesticides and the Microbiome-Gut-Brain Axis: Convergent Pathways in the Pathogenesis of Parkinson's Disease

The increasing global burden of Parkinson's disease (PD), termed the PD pandemic, is exceeding expectations related purely to population aging and is likely driven in part by lifestyle changes and environmental factors. Pesticides are well recognized risk factors for PD, supported by both epidemiological and experimental evidence, with multiple detrimental effects beyond dopaminergic neuron damage alone. The microbiome-gut-brain axis has gained much attention in recent years and is considered to be a significant contributor and driver of PD pathogenesis. In this narrative review, we first focus on how both pesticides and the microbiome may influence PD initiation and progression independently, describing pesticide-related central and peripheral neurotoxicity and microbiome-related local and systemic effects due to dysbiosis and microbial metabolites. We then depict the bidirectional interplay between pesticides and the microbiome in the context of PD, synthesizing current knowledge about pesticide-induced dysbiosis, microbiome-mediated alterations in pesticide availability, metabolism and toxicity, and complex systemic pesticide-microbiome-host interactions related to inflammatory and metabolic pathways, insulin resistance and other mechanisms. An overview of the unknowns follows, and the role of pesticide-microbiome interactions in the proposed body-/brain-first phenotypes of PD, the complexity of environmental exposures and gene-environment interactions is discussed. The final part deals with possible further steps for translation, consisting of recommendations on future pesticide use and research as well as an outline of promising preventive/therapeutic approaches targeted on strengthening or restoring a healthy gut microbiome, closing with a summary of current gaps and future perspectives in the field.

Maternal exposure to air pollution alters energy balance transiently according to gender and changes gut microbiota

Introduction

The timing of maternal exposure to air pollution is crucial to define metabolic changes in the offspring. Here we aimed to determine the most critical period of maternal exposure to particulate matter (PM_2.5) that impairs offspring's energy metabolism and gut microbiota composition.

Methods

Unexposed female and male C57BL/6J mice were mated. PM_2.5 or filtered air (FA) exposure occurred only in gestation (PM_2.5/FA) or lactation (FA/PM_2.5). We studied the offspring of both genders.

Results

PM_2.5 exposure during gestation increased body weight (BW) at birth and from weaning to young in male adulthood. Leptin levels, food intake, Agrp, and Npy levels in the hypothalamus were also increased in young male offspring. Ikbke, Tnf increased in male PM_2.5/FA. Males from FA/PM_2.5 group were protected from these phenotypes showing higher O₂ consumption and Ucp1 in the brown adipose tissue. In female offspring, we did not see changes in BW at weaning. However, adult females from PM_2.5/FA displayed higher BW and leptin levels, despite increased energy expenditure and thermogenesis. This group showed a slight increase in food intake. In female offspring from FA/PM_2.5, BW, and leptin levels were elevated. This group displayed higher energy expenditure and a mild increase in food intake. To determine if maternal exposure to PM_2.5 could affect the offspring's gut microbiota, we analyzed alpha diversity by Shannon and Simpson indexes and beta diversity by the Linear Discriminant Analysis (LDA) in offspring at 30 weeks. Unlike males, exposure during gestation led to higher adiposity and leptin maintenance in female offspring at this age. Gestation exposure was associated with decreased alpha diversity in the gut microbiota in both genders.

Discussion

Our data support that exposure to air pollution during gestation is more harmful to metabolism than exposure during lactation. Male offspring had an unfavorable metabolic phenotype at a young age. However, at an older age, only females kept more adiposity. Ultimately, our data highlight the importance of controlling air pollution, especially during gestation.

Assessing the role of the gut microbiome at the interface between environmental chemical exposures and human health: Current knowledge and challenges

The explosion of microbiome research over the past decade has shed light on the various ways that external factors interact with the human microbiome to drive health and disease. Each individual is exposed to more than 300 environmental chemicals every day. Accumulating evidence indicates that the microbiome is involved in the early response to environmental toxicants and biologically mediates their adverse effects on human health. However, few review articles to date provided a comprehensive framework for research and translation of the role of the gut microbiome in environmental health science. This review summarizes current evidence on environmental compounds and their effect on the gut microbiome, discusses the involved compound metabolic pathways, and covers environmental pollution-induced gut microbiota disorders and their long-term outcomes on host health. We conclude that the gut microbiota may crucially mediate and modify the disease-causing effects of environmental chemicals. Consequently, gut microbiota needs to be further studied to assess the complete toxicity of environmental exposures. Future research in this field is required to delineate the key interactions between intestinal microbiota and environmental pollutants and further to elucidate the long-term human health effects.

The effectiveness of vitamin C on quinalphos ileal toxicity: a study of histological, ultrastructural, and oxidative stress markers

There is a significant hazard of human exposure to the organophosphates which is a constant threat, and they are responsible for numerous cases of poisoning and mammalian toxicity annually in non-target wildlife. The antioxidants, including the vitamin C (Vit C), have a protective effect on some organophosphorus compounds-induced organ damage. Quinalphos (QP) is one of these compounds. The investigation's objective is to see if there was any effect of QP on the rat ileum which could be rectified by using Vit C. Three groups of 24 animals were created. As a control, the first group was given pure water. Second group subjected to oral gavages of QPs. Third group rats were given oral gavages of Vit C plus QPs for 10 days. The reaction of ileal enterocytes to food-borne QPs was marked by poorly organized microvilli, numerous vacuoles within them, disrupted nuclei with chromatin margination, disoriented mitochondria, and an expanded intercellular space. The absorptive columnar cell illustrated many vacuoles inside with herniation of microvilli, and normal goblet cells were also seen. Many Paneth cells towards the lumen of intestinal gland contained secretory granules of different sizes and shapes. The histological architecture of the ileal mucosa in the QP plus Vit C group was found to be close to those of healthy controls. The outcomes of this study suggest that administering Vit C in rats treated with QPs protects them from ill dysfunction caused by QP.

Probiotics, prebiotics, and synbiotics to prevent or combat air pollution consequences: The gut-lung axis

Air pollution exposure is a public health emergency, which attributes globally to an estimated seven million deaths on a yearly basis We are all exposed to air pollutants, varying from ambient air pollution hanging over cities to dust inside the home. It is a mixture of airborne particulate matter and gases that can be subdivided into three categories based on particle diameter. The smallest category called PM_0.1 is the most abundant. A fraction of the particles included in this category might enter the blood stream spreading to other parts of the body. As air pollutants can enter the body via the lungs and gut, growing evidence links its exposure to gastrointestinal and respiratory impairments and diseases, like asthma, rhinitis, respiratory tract infections, Crohn's disease, ulcerative colitis, and abdominal pain. It has become evident that there exists a crosstalk between the respiratory and gastrointestinal tracts, commonly referred to as the gut-lung axis. Via microbial secretions, metabolites, immune mediators and lipid profiles, these two separate organ systems can influence each other. Well-known immunomodulators and gut health stimulators are probiotics, prebiotics, together called synbiotics. They might combat air pollution-induced systemic inflammation and oxidative stress by optimizing the microbiota composition and microbial metabolites, thereby stimulating anti-inflammatory pathways and strengthening mucosal and epithelial barriers. Although clinical studies investigating the role of probiotics, prebiotics, and synbiotics in an air pollution setting are lacking, these interventions show promising health promoting effects by affecting the gastrointestinal- and respiratory tract. This review summarizes the current data on how air pollution can affect the gut-lung axis and might impact gut and lung health. It will further elaborate on the potential role of probiotics, prebiotics and synbiotics on the gut-lung axis, and gut and lung health.

Nigella sativa oil protects against cadmium-induced intestinal toxicity via promotion of anti-inflammatory mechanisms, mucin expression and microbiota integrity

Objective

This study examined the protective effects of Nigella sativa oil (NSO) on cadmium (Cd)-induced alterations affecting gut morphology and microbiota composition, as well as the involvement of mucus glycoprotein (MUC2) and immuno-inflammatory markers (TNFα and IL-2) in the colon of rats.

Materials and Methods

Male Wistar rats, randomized into four groups, were treated either with distilled water (control), CdCl₂ (100 mg/kg), CdCl₂+NSO (1 ml/kg) or NSO alone. After the experiments, faecal samples were processed for microbial culture on various selective media, while intestinal segments were prepared for histopathological examination and immunohistochemistry. The composition of NSO was analyzed using Gas Chromatography-Mass Spectrometry (GC-MS).

Results

Oral Cd administration provoked dramatic increases in faecal counts of potentially pathogenic bacteria (Staphylococci, Enterococci, Pseudomonas and Escherichia coli), while decreasing probiotic lactobacilli counts. Cadmium treatment caused down-regulation of colonic MUC2 (p=0.003) and IL-2 (p=0.03), but increased TNFα (p=0.034), along with reduced goblet cell counts and mucus production. Conversely, treatment with NSO significantly improved Lactobacilli counts (p=0.042), while reducing the levels of potentially pathogenic species. In addition, NSO significantly restored colonic expressions of MUC2 (p=0.001), TNFα (p=0.007) and IL-2 (p=0.025) to control levels. GC-MS analysis of NSO revealed the presence of the active ingredient, thymoquinone and a high content of unsaturated fatty acids, including trans-13-octadecenoic acid and oleic acid.

Conclusion

This study highlights the intestinal mucus, microbiota and immuno-inflammatory system as important protective targets of NSO against Cd-induced intestinal toxicity.

Green sweet potato leaves increase Nrf2-mediated antioxidant activity and facilitate benzo[a]pyrene metabolism in the liver by increasing phase II detoxifying enzyme activities in rats

Green and purple SPL consumption may enhance the Nrf2-mediated hepatic antioxidant activity and modulate xenobiotic-metabolizing enzymes and transporters via different mechanisms.

The impact of selected food additives on the gastrointestinal tract in the example of nonspecific inflammatory bowel diseases

Various types of food additives are widely used in the food industry. Due to their properties extending the usefulness for consuming food products, they give them different colours, consistency, or taste. The products are marked 'E' and the code is assigned to the subscription used. Many of the supplements affect human health negatively. Emulsifiers or stabilizers can lead to epithelial loads and the development of inflammation. Sucrose and other sweeteners may change the composition of the intestinal microflora and thus lead to intestinal blockage. Some additives classified as preservatives are available and may predispose to intestinal dysbiosis. Available substances belonging to food dyes may predispose to genotoxic and cytotoxic effects and cause inflammation in the intestines. Substances added to food can also cause disorders of intestinal homeostasis.

Intestinal mucus barrier: a missing piece of the puzzle in food allergy

The prevalence of food allergies has reached epidemic levels but the cause remains largely unknown. We discuss the clinical relevance of the gut mucosal barrier as a site for allergic sensitization to food. In this context, we focus on an important but overlooked part of the mucosal barrier in pathogenesis, the glycoprotein-rich mucus layer, and call attention to both beneficial and detrimental aspects of mucus-gut microbiome interactions. Studying the intricate links between the mucus barrier, the associated bacteria, and the mucosal immune system may advance our understanding of the mechanisms and inform prevention and treatment strategies in food allergy.

Environmental Occurrence, Toxicity Concerns, and Degradation of Diazinon Using a Microbial System

Diazinon is an organophosphorus pesticide widely used to control cabbage insects, cotton aphids and underground pests. The continuous application of diazinon in agricultural activities has caused both ecological risk and biological hazards in the environment. Diazinon can be degraded via physical and chemical methods such as photocatalysis, adsorption and advanced oxidation. The microbial degradation of diazinon is found to be more effective than physicochemical methods for its complete clean-up from contaminated soil and water environments. The microbial strains belonging to Ochrobactrum sp., Stenotrophomonas sp., Lactobacillus brevis, Serratia marcescens, Aspergillus niger, Rhodotorula glutinis, and Rhodotorula rubra were found to be very promising for the ecofriendly removal of diazinon. The degradation pathways of diazinon and the fate of several metabolites were investigated. In addition, a variety of diazinon-degrading enzymes, such as hydrolase, acid phosphatase, laccase, cytochrome P450, and flavin monooxygenase were also discovered to play a crucial role in the biodegradation of diazinon. However, many unanswered questions still exist regarding the environmental fate and degradation mechanisms of this pesticide. The catalytic mechanisms responsible for enzymatic degradation remain unexplained, and ecotechnological techniques need to be applied to gain a comprehensive understanding of these issues. Hence, this review article provides in-depth information about the impact and toxicity of diazinon in living systems and discusses the developed ecotechnological remedial methods used for the effective biodegradation of diazinon in a contaminated environment.

Ingested Engineered Nanomaterials Affect the Expression of Mucin Genes-An In Vitro-In Vivo Comparison

The increasing use of engineered nanomaterials (ENM) in food has fueled the development of intestinal in vitro models for toxicity testing. However, ENM effects on intestinal mucus have barely been addressed, although its crucial role for intestinal health is evident. We investigated the effects of ENM on mucin expression and aimed to evaluate the suitability of four in vitro models of increasing complexity compared to a mouse model exposed through feed pellets. We assessed the gene expression of the mucins MUC1, MUC2, MUC5AC, MUC13 and MUC20 and the chemokine interleukin-8 in pre-confluent and confluent HT29-MTX-E12 cells, in stable and inflamed triple cultures of Caco-2, HT29-MTX-E12 and THP-1 cells, and in the ileum of mice following exposure to TiO₂, Ag, CeO₂ or SiO₂. All ENM had shared and specific effects. CeO₂ downregulated MUC1 in confluent E12 cells and in mice. Ag induced downregulation of Muc2 in mice. Overall, the in vivo data were consistent with the findings in the stable triple cultures and the confluent HT29-MTX-E12 cells but not in pre-confluent cells, indicating the higher relevance of advanced models for hazard assessment. The effects on MUC1 and MUC2 suggest that specific ENM may lead to an elevated susceptibility towards intestinal infections and inflammations.

Inflammatory and Microbiota-Related Regulation of the Intestinal Epithelial Barrier

The intestinal epithelial barrier (IEB) is one of the largest interfaces between the environment and the internal milieu of the body. It is essential to limit the passage of harmful antigens and microorganisms and, on the other side, to assure the absorption of nutrients and water. The maintenance of this delicate equilibrium is tightly regulated as it is essential for human homeostasis. Luminal solutes and ions can pass across the IEB via two main routes: the transcellular pathway or the paracellular pathway. Tight junctions (TJs) are a multi-protein complex responsible for the regulation of paracellular permeability. TJs control the passage of antigens through the IEB and have a key role in maintaining barrier integrity. Several factors, including cytokines, gut microbiota, and dietary components are known to regulate intestinal TJs. Gut microbiota participates in several human functions including the modulation of epithelial cells and immune system through the release of several metabolites, such as short-chain fatty acids (SCFAs). Mediators released by immune cells can induce epithelial cell damage and TJs dysfunction. The subsequent disruption of the IEB allows the passage of antigens into the mucosa leading to further inflammation. Growing evidence indicates that dysbiosis, immune activation, and IEB dysfunction have a role in several diseases, including irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), and gluten-related conditions. Here we summarize the interplay between the IEB and gut microbiota and mucosal immune system and their involvement in IBS, IBD, and gluten-related disorders.

Microplastics in the human digestive environment: A focus on the potential and challenges facing in vitro gut model development

Plastic pollution is a major issue worldwide, generating massive amounts of smaller plastic particles, including microplastics (MPs). Their ubiquitous nature in the environment but also in foodstuff and consumer packaged goods has revealed potential threats to humans who can be contaminated mainly through air, food and water consumption. In this review, the current literature on human exposure to MPs is summarized with a focus on the gastrointestinal tract as portal of entry. Then, we discuss the vector effect of MPs, in their pristine versus weathered forms, with well-known contaminants as heavy metals and chemicals, or more emerging ones as antibiotics or microbial pathogens, like Pseudomonas spp., Vibrio spp., Campylobacter spp. and Escherichia coli. Comprehensive knowledge on MP fate in the gastrointestinal tract and their potential impact on gut homeostasis disruption, including gut microbiota, mucus and epithelial barrier, is reported in vitro and in vivo in mammals. Special emphasis is given on the crucial need of developing robust in vitro gut models to adequately simulate human digestive physiology and absorption processes. Finally, this review points out future research directions on MPs in human intestinal health.

Dietary Nanoparticles Interact with Gluten Peptides and Alter the Intestinal Homeostasis Increasing the Risk of Celiac Disease

The introduction of metallic nanoparticles (mNPs) into the diet is a matter of concern for human health. In particular, their effect on the gastrointestinal tract may potentially lead to the increased passage of gluten peptides and the activation of the immune response. In consequence, dietary mNPs could play a role in the increasing worldwide celiac disease (CeD) incidence. We evaluated the potential synergistic effects that peptic-tryptic-digested gliadin (PT) and the most-used food mNPs may induce on the intestinal mucosa. PT interaction with mNPs and their consequent aggregation was detected by transmission electron microscopy (TEM) analyses and UV-Vis spectra. In vitro experiments on Caco-2 cells proved the synergistic cytotoxic effect of PT and mNPs, as well as alterations in the monolayer integrity and tight junction proteins. Exposure of duodenal biopsies to gliadin plus mNPs triggered cytokine production, but only in CeD biopsies. These results suggest that mNPs used in the food sector may alter intestinal homeostasis, thus representing an additional environmental risk factor for the development of CeD.

Food emulsifier polysorbate 80 promotes the intestinal absorption of mono-2-ethylhexyl phthalate by disturbing intestinal barrier

Di-2-ethylhexyl phosphate (DEHP) and its main toxic metabolite mono-2-ethylhexyl phthalate (MEHP) are the typical endocrine disrupting chemicals (EDCs) and widely affect human health. Our previous research reported that synthetic nonionic dietary emulsifier polysorbate 80 (P80, E433) had the promotional effect on the oral absorption of DEHP in rats. The aim of this study was to explore its mechanism of promoting oral absorption, focusing on the mucus barrier and mucosal barrier of the small intestine. A small molecule fluorescent probe 5-aminofluorescein-MEHP (MEHP-AF) was used as a tracker of MEHP in vivo and in vitro. First of all, we verified that P80 promoted the bioavailability of MEHP-AF in the long-term and low-dose exposure of MEHP-AF with P80 as a result of increasing the intestinal absorption of MEHP-AF. Afterwards, experimental results from Western blot, qPCR, immunohistochemistry, and immunofluorescence showed that P80 decreased the expression of proteins (mucus protein mucin-2, tight junction proteins claudin-1 and occludin) related to mucus barrier and mucosal barrier in the intestine, changed the integrity of intestinal epithelial cell, and increased the permeability of intestinal epithelial mucosa. These results indicated that P80 promoted the oral absorption of MEHP-AF by altering the intestinal mucus barrier and mucosal barrier. These findings are of great importance for assessing the safety risks of some food emulsifiers and clarifying the absorption mechanism of chemical pollutants in food, especially for EDCs.

From "Leaky Gut" to Impaired Glia-Neuron Communication in Depression

In the last three decades, the robust scientific data emerged, demonstrating that the immune-inflammatory response is a fundamental component of the pathophysiology of major depressive disorder (MDD). Psychological stress and various inflammatory comorbidities contribute to such immune activation. Still, this is not uncommon that patients with depression do not have defined inflammatory comorbidities, and alternative mechanisms of immune activation need to take place. The gastrointestinal (GI) tract, along with gut-associated lymphoid tissue (GALT), constitutes the largest lymphatic organ in the human body and forms the biggest surface of contact with the external environment. It is also the most significant source of bacterial and food-derived antigenic material. There is a broad range of reciprocal interactions between the GI tract, intestinal microbiota, increased intestinal permeability, activation of immune-inflammatory response, and the CNS that has crucial implications in brain function and mental health. This intercommunication takes place within the microbiota-gut-immune-glia (MGIG) axis, and glial cells are the main orchestrator of this communication. A broad range of factors, including psychological stress, inflammation, dysbiosis, may compromise the permeability of this barrier. This leads to excessive bacterial translocation and the excessive influx of food-derived antigenic material that contributes to activation of the immune-inflammatory response and depressive psychopathology. This chapter summarizes the role of increased intestinal permeability in MDD and mechanisms of how the "leaky gut" may contribute to immune-inflammatory response in this disorder.

Gait and balance disturbances are common in young urbanites and associated with cognitive impairment. Air pollution and the historical development of Alzheimer's disease in the young

To determine whether gait and balance dysfunction are present in young urbanites exposed to fine particular matter PM2.5 ≥ annual USEPA standard, we tested gait and balance with Tinetti and Berg tests in 575 clinically healthy subjects, age 21.0 ± 5.7 y who were residents in Metropolitan Mexico City, Villahermosa and Reynosa. The Montreal Cognitive Assessment was also applied to an independent cohort n:76, age 23.3 ± 9.1 y. In the 575 cohort, 75.4% and 34.4% had abnormal total Tinetti and Berg scores and high risk of falls in 17.2% and 5.7% respectively. BMI impacted negatively Tinetti and Berg performance. Gait dysfunction worsen with age and males performed worse than females. Gait and balance dysfunction were associated with mild cognitive impairment MCI (19.73%) and dementia (55.26%) in 57/76 and 19 cognitively intact subjects had gait and balance dysfunction. Seventy-five percent of urbanites exposed to PM2.5 had gait and balance dysfunction. For MMC residents-with historical documented Alzheimer disease (AD) and CSF abnormalities, these findings suggest Alzheimer Continuum is in progress. Early development of a Motoric Cognitive Risk Syndrome ought to be considered in city dwellers with normal cognition and gait dysfunction. The AD research frame in PM2.5 exposed young urbanites should include gait and balance measurements. Multicity teens and young adult cohorts are warranted for quantitative gait and balance measurements and neuropsychological and brain imaging studies in high vs low PM2.5 exposures. Early identification of gait and balance impairment in young air pollution-exposed urbanites would facilitate multidisciplinary prevention efforts for modifying the course of AD.

Environmental Nanoparticles, SARS-CoV-2 Brain Involvement, and Potential Acceleration of Alzheimer's and Parkinson's Diseases in Young Urbanites Exposed to Air Pollution

Alzheimer's and Parkinson's diseases (AD, PD) have a pediatric and young adult onset in Metropolitan Mexico City (MMC). The SARS-CoV-2 neurotropic RNA virus is triggering neurological complications and deep concern regarding acceleration of neuroinflammatory and neurodegenerative processes already in progress. This review, based on our MMC experience, will discuss two major issues: 1) why residents chronically exposed to air pollution are likely to be more susceptible to SARS-CoV-2 systemic and brain effects and 2) why young people with AD and PD already in progress will accelerate neurodegenerative processes. Secondary mental consequences of social distancing and isolation, fear, financial insecurity, violence, poor health support, and lack of understanding of the complex crisis are expected in MMC residents infected or free of SARS-CoV-2. MMC residents with pre-SARS-CoV-2 accumulation of misfolded proteins diagnostic of AD and PD and metal-rich, magnetic nanoparticles damaging key neural organelles are an ideal host for neurotropic SARS-CoV-2 RNA virus invading the body through the same portals damaged by nanoparticles: nasal olfactory epithelium, the gastrointestinal tract, and the alveolar-capillary portal. We urgently need MMC multicenter retrospective-prospective neurological and psychiatric population follow-up and intervention strategies in place in case of acceleration of neurodegenerative processes, increased risk of suicide, and mental disease worsening. Identification of vulnerable populations and continuous effort to lower air pollution ought to be critical steps.

Hairy Region Concentrate of Pectin Strongly Stimulates Mucin Secretion in HT29-MTX Cells, but to a Lessor Degree in Rat Small Intestine

Pectin enhances mucin secretion in the rat small intestine. However, what structural features of pectin to stimulate mucin secretion remain unclear. The study aimed to clarify active constituents of pectin using a human goblet cell line, HT29-MTX. Various pectins at 100 mg/L commonly stimulated MUC5AC secretion, irrespective of their differences in molecular size, plant origin and degree of methoxylation, whereas other dietary fiber materials at 100 mg/L did not show any effects, except fucoidan. Hairy region concentrate (HRC) and its further fractions (F1-F3) were prepared by polygalacturonase treatment of citrus pectin and successive anion exchange chromatography. Neutral sugars, such as galactose and arabinose were enriched in these fractions. HRC and F1-F3 at 30 mg/L significantly increased MUC5AC secretion, which were 3 times more potent compared with a starting material (citrus pectin). Further, a dose-dependent study showed that F1 significantly increased MUC5AC secretion from at 0.3 mg/L, much stronger than that of mucin-secretagogue lipopolysaccharides. Rats consumed 5% apple pectin diet showed significant increases of luminal mucin contents and Muc2 expression in the small intestine, while the luminal mucin contents in rats consumed 1.5% HRC diet were increased by 24% compared to those in rats consumed control diet, but the difference did not reach significant. Thus, HRC is supposed to be active constituents of mucin-secretory effect of pectin in vitro. At present, however, the effect of HRC has not been verified in vivo.

High-Fat Diet Affects Heavy Metal Accumulation and Toxicity to Mice Liver and Kidney Probably via Gut Microbiota

Previous studies proved that heavy metals could increase the risk of disease by acting on the gut microbiota. Meanwhile, gut microbiota played important roles in detoxifying heavy metals. However, the response of gut microbiota to heavy metals and which microbes dominated this detoxification processes are still unclear. This study investigated the difference of high-fat-diet (HFD) and normal-diet (ND) gut microbiota and their response to and detoxification effects on arsenic (As), cadmium (Cd), and lead (Pb) exposure. Results showed that gut microbiota of ND and HFD was significantly different and responded to As, Pb, and Cd exposure differently, too. When exposed to 100 ppm As, Cd, or Pb, HFD-fed mice accumulated more heavy metals in the liver and kidney along with more severe functional damage than ND-fed mice, indicated by a more dramatic increase of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities and urinary total protein (TPU), urinary uric acid (UUA), and urinary creatinine (Ucrea) content. Among ND gut microbiota, relative abundance of Bacteroides, Lactobacillus, Butyricimonas, and Dorea was significantly increased by arsenic (As) exposure; relative abundance of Faecoccus and Lactobacillus was significantly increased by Cd exposure; relative abundance of Desulfovibrio, Plasmodium, and Roseburia were significantly increased by Pb exposure. However, among HFD gut microbiota, those microbes were not significantly changed. Bivariate association analysis found weak positive correlations between content of fecal excreted heavy metals and richness of total fecal microbiota as well as abundance of some of the heavy metal-enriched microbes. Our study concluded that HFD increased disease risk of heavy metal exposure probably via its gut microbiota which excreted less heavy metal through feces.

An indoor study of the combined effect of industrial pollution and turbulence events on the gut environment in a marine invertebrate

Natural storms are able to determine reworking of seabed up to considerable depths and favour suspension of sediment-associated chemicals. Yet, a direct link between exposure to resuspended contaminants and the biological effects on marine organisms have to be fully established. We exposed adults of a suspension feeder, the ascidian Ciona robusta, to polluted sediment (e.g., containing mixtures of polycyclic aromatic hydrocarbons and heavy metals) from the industrial area of Bagnoli-Coroglio under two temporal patterns ('aggregated' vs. 'spaced') of turbulence events. Then, we assessed the impact of resuspended pollutants on the ascidian gut environment via four broad categories: oxidative stress, innate immunity, host-microbiota interactions, and epithelium. An early oxidative stress response was seen after a week of exposure to static sediment. Instead, water turbulence had no effect on the antioxidant defence. The first episode of turbulent suspension induced a minimal pro-inflammatory response in the 'spaced' pattern. Mucus overproduction and a complete occlusion of the crypt lumen were found following sediment reworking. This study suggests a protective response of the gut environment in marine invertebrates exposed to environmental extremes, leading to increased susceptibility to disease and to concerns on the combined effects of chronic environmental contamination and acute disturbance events possibly associated with climate change.

TiO2 Nanoparticles and Commensal Bacteria Alter Mucus Layer Thickness and Composition in a Gastrointestinal Tract Model

Nanoparticles (NPs) are used in food packaging and processing and have become an integral part of many commonly ingested products. There are few studies that have focused on the interaction between ingested NPs, gut function, the mucus layer, and the gut microbiota. In this work, an in vitro model of gastrointestinal (GI) tract is used to determine whether, and how, the mucus layer is affected by the presence of Gram-positive, commensal Lactobacillus rhamnosus; Gram-negative, opportunistic Escherichia coli; and/or exposure to physiologically relevant doses of pristine or digested TiO2 NPs. Caco-2/HT29-MTX-E12 cell monolayers are exposed to physiological concentrations of bacteria (expressing fluorescent proteins) and/or TiO2 nanoparticles for a period of 4 h. To determine mucus thickness and composition, cell monolayers are stained with alcian blue, periodic acid schiff, or an Alexa Fluor 488 conjugate of wheat germ agglutinin. It is found that the presence of both bacteria and nanoparticles alter the thickness and composition of the mucus layer. Changes in the distribution or pattern of mucins can be indicative of pathological conditions, and this model provides a platform for understanding how bacteria and/or NPs may interact with and alter the mucus layer.

The Nano-Intestine Interaction: Understanding the Location-Oriented Effects of Engineered Nanomaterials in the Intestine

Engineered nanomaterials (ENMs) are used in food additives, food packages, and therapeutic purposes owing to their useful properties, Therefore, human beings are orally exposed to exogenous nanomaterials frequently, which means the intestine is one of the primary targets of nanomaterials. Consequently, it is of great importance to understand the interaction between nanomaterials and the intestine. When nanomaterials enter into gut lumen, they inevitably interact with various components and thereby display different effects on the intestine based on their locations; these are known as location-oriented effects (LOE). The intestinal LOE confer a new biological-effect profile for nanomaterials, which is dependent on the involvement of the following biological processes: nano-mucus interaction, nano-intestinal epithelial cells (IECs) interaction, nano-immune interaction, and nano-microbiota interaction. A deep understanding of NM-induced LOE will facilitate the design of safer NMs and the development of more efficient nanomedicine for intestine-related diseases. Herein, recent progress in this field is reviewed in order to better understand the LOE of nanomaterials. The distant effects of nanomaterials coupling with microbiota are also highlighted. Investigation of the interaction of nanomaterials with the intestine will stimulate other new research areas beyond intestinal nanotoxicity.

The complex puzzle of dietary silver nanoparticles, mucus and microbiota in the gut

Hundreds of consumer and commercial products containing silver nanoparticles (AgNPs) are currently used in food, personal-care products, pharmaceutical, and many other applications. Human exposure to AgNPs includes oral intake, inhalation, and dermal contact. The aim of this review was to focus on oral intake, intentional and incidental of AgNPs where well-known antimicrobial characteristics that might affect the microbiome and mucus in the gastrointestinal tract (GIT). This critical review summarizes what is known regarding the impacts of AgNPs on gut homeostasis. It is fundamental to understand the forms of AgNPs and their physicochemical characterization before and during digestion. For example, lab-synthesized AgNPs differ from "real" ingestable AgNPs used as food additives and dietary supplements. Similarly, the gut environment alters the chemical and physical state of Ag that is ingested as AgNPs. Emerging research on in vitro and in vivo rodent and human indicated complex multi-directional relationships among AgNPs, the intestinal microbiota, and the epithelial mucus. It may be necessary to go beyond today's descriptive approach to a modeling-based ecosystem approach that might quantitatively integrate spatio-temporal interactions among microbial groups, host factors (e.g., mucus), and environmental factors, including lifestyle-based stressors. It is suggested that future research (1) utilize more representative AgNPs, focus on microbe/mucus interactions, (2) assess the effects of environmental stressors for longer and longitudinal conditions, and (3) be integrated using quantitative modeling.

Subchronic exposure of environmentally relevant concentrations of F-53B in mice resulted in gut barrier dysfunction and colonic inflammation in a sex-independent manner

F-53B (6:2 chlorinated polyfluorinated ether sulfonate) is currently recognized as a safe alternative to long-chain PFASs in China. However, an increasing number of studies have recently authenticated its biotoxicological effects. In this study, for evaluating the gut toxicity of F-53B in mammals, both female and male mice were orally exposed to 0, 1, 3, or 10 μg/L F-53B for 10 weeks. Our results showed that F-53B significantly accumulated in the colon, ileum and serum when exposed to 10 μg/L F-53B for 10 weeks. F-53B exposure not only increased the transcriptional levels of ion transport-related genes but could also interact with the CFTR protein directly. Interestingly, subchronic F-53B exposure also increased the transcription of mucus secretion-related genes, but the protein level of Muc2 decreased after F-53B exposure, indicating that there was a compensatory phenomenon after mucus barrier injury. Furthermore, F-53B exposure also induced colonic inflammation associated with gut microbiota dysbiosis in the colon. Taken together, our results indicated that the potential gut toxicity of F-53B and almost all of the changed parameters were significantly affected in both female and male mice, suggesting that F-53B could disturb the gut barrier without sex dependence in mice.

Combustion and friction-derived nanoparticles and industrial-sourced nanoparticles: The culprit of Alzheimer and Parkinson's diseases

Redox-active, strongly magnetic, combustion and friction-derived nanoparticles (CFDNPs) are abundant in particulate matter air pollution. Urban children and young adults with Alzheimer disease Continuum have higher numbers of brain CFDNPs versus clean air controls. CFDNPs surface charge, dynamic magnetic susceptibility, iron content and redox activity contribute to ROS generation, neurovascular unit (NVU), mitochondria, and endoplasmic reticulum (ER) damage, and are catalysts for protein misfolding, aggregation and fibrillation. CFDNPs respond to external magnetic fields and are involved in cell damage by agglomeration/clustering, magnetic rotation and/or hyperthermia. This review focus in the interaction of CFDNPs, nanomedicine and industrial NPs with biological systems and the impact of portals of entry, particle sizes, surface charge, biomolecular corona, biodistribution, mitochondrial dysfunction, cellular toxicity, anterograde and retrograde axonal transport, brain dysfunction and pathology. NPs toxicity information come from researchers synthetizing particles and improving their performance for drug delivery, drug targeting, magnetic resonance imaging and heat mediators for cancer therapy. Critical information includes how these NPs overcome all barriers, the NPs protein corona changes as they cross the NVU and the complexity of NPs interaction with soluble proteins and key organelles. Oxidative, ER and mitochondrial stress, and a faulty complex protein quality control are at the core of Alzheimer and Parkinson's diseases and NPs mechanisms of action and toxicity are strong candidates for early development and progression of both fatal diseases. Nanoparticle exposure regardless of sources carries a high risk for the developing brain homeostasis and ought to be included in the AD and PD research framework.

Gut microbiota: An underestimated and unintended recipient for pesticide-induced toxicity

Pesticide pollution residues have become increasingly common health hazards over the last several decades because of the wide use of pesticides. The gastrointestinal tract is the first physical and biological barrier to contaminated food and is therefore the first exposure site. Interestingly, a number of studies have shown that the gut microbiota plays a key role in the toxicity of pesticides and has a profound relationship with environmental animal and human health. For instance, intake of the pesticide of chlorpyrifos can promote obesity and insulin resistance through influencing gut and gut microbiota of mice. In this review, we discussed the possible effects of different kinds of widely used pesticides on the gut microbiota in different experimental models and analyzed their possible subsequent effects on the health of the host. More and more studies indicated that the gut microbiota of animals played a very important role in pesticides-induced toxicity, suggesting that gut micriobita was also the unintended recipient of pesticides. We hope that more attention can focus on the relationship between pesticides, gut microbiota and environmental health risk assessment in near future.

Experimental models to study intestinal microbes–mucus interactions in health and disease

A close symbiotic relationship exists between the intestinal microbiota and its host. A critical component of gut homeostasis is the presence of a mucus layer covering the gastrointestinal tract. Mucus is a viscoelastic gel at the interface between the luminal content and the host tissue that provides a habitat to the gut microbiota and protects the intestinal epithelium. The review starts by setting up the biological context underpinning the need for experimental models to study gut bacteria-mucus interactions in the digestive environment. We provide an overview of the structure and function of intestinal mucus and mucins, their interactions with intestinal bacteria (including commensal, probiotics and pathogenic microorganisms) and their role in modulating health and disease states. We then describe the characteristics and potentials of experimental models currently available to study the mechanisms underpinning the interaction of mucus with gut microbes, including in vitro, ex vivo and in vivo models. We then discuss the limitations and challenges facing this field of research.

Nanoparticles and danger signals: Oral delivery vehicles as potential disruptors of intestinal barrier homeostasis

Gut immune system homeostasis involves diverse structural interactions among resident microbiota, the protective mucus layer, and a variety of cells (intestinal epithelial, lymphoid, and myeloid). Due to the substantial surface area in direct contact with an "external" environment and the diversity of xenobiotic, abiotic, and self-interactions coordinating to maintain gut homeostasis, there is enhanced potential for the generation of endogenous danger signals when this balance is lost. Here, we focus on the potential generation and reception of damage in the gut resulting from exposure to nanoparticles (NPs), common food and drug additives. Specifically, we describe recent evidence in the literature showing that certain NPs are potential generators of damage-associated molecular patterns, as well as potential immune-stimulating molecular patterns themselves.

Special Issue: Gut Bacteria-Mucus Interaction

The mucus layer covering the gastrointestinal tract plays a critical role in maintaining a homeostatic relationship with our gut microbiota. [...].