Interactions between Food Hazards and Intestinal Barrier: Impact on Foodborne Diseases

Recent advances in metal oxide nanozyme-based optical biosensors for food safety assays

Metal oxide nanozymes are emerging as promising materials for food safety detection, offering several advantages over natural enzymes, including superior stability, cost-effectiveness, large-scale production capability, customisable functionality, design options, and ease of modification. Optical biosensors based on metal oxide nanozymes have significantly accelerated the advancement of analytical research, facilitating the rapid, effortless, efficient, and precise detection and characterisation of contaminants in food. However, few reviews have focused on the application of optical biosensors based on metal oxide nanozymes for food safety detection. In this review, the catalytic mechanisms of the catalase, oxidase, peroxidase, and superoxide dismutase activities of metal oxide nanozymes are characterized. Research developments in optical biosensors based on metal oxide nanozymes, including colorimetric, fluorescent, chemiluminescent, and surface-enhanced Raman scattering biosensors, are comprehensively summarized. The application of metal oxide nanozyme-based biosensors for the detection of nitrites, sulphites, metal ions, pesticides, antibiotics, antioxidants, foodborne pathogens, toxins, and other food contaminants has been highlighted. Furthermore, the challenges and future development prospects of metal oxide nanozymes for sensing applications are discussed. This review offers insights and inspiration for further investigations on optical biosensors based on metal oxide nanozymes for food safety detection.

Fermentation enhances the amelioration effect of bee pollen on Caco-2 monolayer epithelial barrier dysfunction based on NF-κB-mediated MLCK-MLC signaling pathway

Intestinal barrier integrity is essential for normal nutrient digestion and absorption and disease resistance. This study aims to investigate how fermentation affects the ameliorative effect of bee pollen on the intestinal barrier dysfunction stimulated by interferon-γ and tumor necrosis factor (IFN-γ/TNF-α) cytokines. The results indicated that fermentation enhances the alleviating effect of bee pollen on intestinal barrier dysfunction (including elevated trans epithelial electrical resistance and decreased paracellular permeability). In addition, fermented bee pollen (FBP) significantly decreased (p < 0.05) the secretion levels of interleukin (IL)-6, IL-8, and IL-1β and expression of cyclooxygenase (COX)-2 protein in intestinal barrier cells. Furthermore, fermentation improved the ability of bee pollen to up-regulate the expression of tight junction proteins including zonula occludens (ZO)-1, occluding, and claudin-1. Notably, FBP showed stronger ability to inhibit the expression of nuclear factor kappa-B (NF-κB) mediated myosin light chain kinase (MLCK) and myosin light chain (MLC) signaling pathway associated with phosphorylated proteins. Overall, our results indicated that fermentation enhances the protective effect of bee pollen on the intestinal barrier, and FBP has promising potential to be used as a novel functional food to protect the intestinal barrier.

PI3K/Akt signaling pathway mediates the effect of low-dose boron on barrier function, proliferation and apoptosis in rat intestinal epithelial cells

Boron is an essential trace element with roles in growth, development, and physiological functions; however, its mechanism of action is still unclear. In this study, the regulatory roles of the PI3K/Akt signaling pathway on boron-induced changes in barrier function, proliferation, and apoptosis in rat intestinal epithelial cells were evaluated. Occludin levels, the proportion of cells in the G2/M phase, cell proliferation rate, and mRNA and protein expression levels of PCNA were higher, while the proportions of cells in the G0/G1 and S phases, apoptosis rate, and caspase-3 mRNA and protein expression levels were lower in cells treated with 0.8 mmol/L boron than in control IEC-6 cells (P < 0.01 or P < 0.05). However, 40 mmol/L boron decreased ZO-1 and Occludin levels, the proportion of cells in the G2/M phase, cell proliferation rate, and mRNA and protein levels of PCNA and increased the apoptosis rate and caspase-3 mRNA expression (P < 0.01 or P < 0.05). After specifically blocking PI3K and Akt signals (using LY294002 and MK-2206 2HCL), 0.8 mmol/L boron had no effects on Occludin, PCNA level, apoptosis rates, and caspase-3 levels (P < 0.05); however, the proliferation rate and PCNA levels decreased significantly (P < 0.01 or P < 0.05). The addition of 40 mmol/L boron did not affect ZO-1 and Occludin levels and did not affect the apoptosis rate or PCNA and caspase-3 levels. These results suggested that the PI3K/Akt signaling pathway mediates the effects of low-dose boron on IEC-6 cells.

Longan Polysaccharides with Covalent Selenylation Combat the Fumonisin B1-Induced Cell Toxicity and Barrier Disruption in Intestinal Epithelial (IEC-6) Cells

In this study, the soluble, but non-digestible, longan (Dimocarpus longan Lour.) polysaccharides (LP) were extracted from dried longan fruits and then chemically selenylated to produce two selenylated products, namely SeLP1 and SeLP2, with different selenylation extents. The aim was to investigate their protective effects on rat intestinal epithelial (IEC-6) cells exposed to the food toxin fumonisin B1 (FB1). LP only contained total Se content of less than 0.01 g/kg, while SeLP1 and SeLP2 were measured with respective total Se content of up to 1.46 and 4.79 g/kg. The cell viability results showed that these two selenylated products were more efficient than LP in the IEC-6 cells in alleviating FB1-induced cell toxicity, suppressing lactate dehydrogenase (LDH) release, and decreasing the generation of intracellular reactive oxygen species (ROS). These two selenylated products were also more effective than LP in combating FB1-induced barrier disruption via increasing the transepithelial electric resistance (TEER), reducing the paracellular permeability, decreasing the mitochondrial membrane potential (MMP) loss, and maintaining cell barrier integrity by upregulating the tight-junction-related genes and proteins. FB1 caused cell oxidative stress and barrier dysfunction by activating the MAPK and mitochondrial apoptosis signaling pathways, while SeLP1 and SeLP2 could regulate the tMAPK- and apoptosis-related proteins to suppress the FB1-mediated activation of the two pathways. Overall, SeLP2 was observed to be more active than SeLP1 in the IEC-6 cells. In conclusion, the chemical selenylation of LP caused an activity enhancement to ameliorate the FB1-induced cell cytotoxicity and intestinal barrier disruption. Meanwhile, the increased selenylation of LP would endow the selenylated product SeLP2 with more activity.

Potential Benefits of Egg White Proteins and Their Derived Peptides in the Regulation of the Intestinal Barrier and Gut Microbiota: A Comprehensive Review

Impaired intestinal barrier function can impede the digestion and absorption of nutrients and cause a range of metabolic disorders, which are the main causes of intestinal disease. Evidence suggests that proper dietary protein intake can prevent and alleviate intestinal diseases. Egg white protein (EWP) has received considerable attention, because of its high protein digestibility and rich amino acid composition. Furthermore, bioactive peptides may have an increased repair effect due to their high degradation efficiency in the gut. In this study, we aimed to review the effects of EWP and its bioactive peptides on intestinal structural repair. The potential modulation mechanisms by which EWP and their peptides regulate the gut microbiota and intestinal barrier can be summarized as follows: (1) restoring the structure of the intestinal barrier to its intact form, (2) enhancing the intestinal immune system and alleviating the inflammatory response and oxidative damage, and (3) increasing the relative abundance of beneficial bacteria and metabolites. Further in-depth analysis of the coregulation of multiple signaling pathways by EWP is required, and the combined effects of these multiple mechanisms requires further evaluation in experimental models. Human trials can be considered to understand new directions for development.

New insights into the role of metal(loid)s in the development of ulcerative colitis: a systematic review

The relationship between heavy metals and ulcerative colitis (UC) was investigated in several studies, but their results were not consistent. Therefore, in this systematic review study, the positive and negative effects of metal(loid)s (Zn, Cu, Fe, Se, Pb, Ni, and As) on UC disease were investigated. In this systematic search, 13 original articles from 1993 to 2021 were identified in Google Scholar, Science Direct, Scopus, PubMed, and the Web of Science databases. In included studies, the concentrations of heavy metals and essential elements were measured in the blood, serum, intestinal biopsies, and hair samples of the patients. Some studies have also examined the heavy metal concentration in UC patients' diet and their drinking water. In the serum samples, Pb (220 ± 108 mg/L) and Cu (401.5 ± 104 µg/L) had the maximum concentrations among the other elements, as well as Zn and Fe had the highest levels in hair and intestinal tissue samples, respectively. In light of the selected articles, there is a possibility of a preventive role for Se and Zn in UC development. Moreover, exposure to Fe can exacerbate the symptoms of the disease. In conclusion, this review reveals that toxic metals, as ubiquitous environmental pollutants, can contribute to the exacerbation of inflammatory intestinal symptoms, and consumption of essential elements can play a vital role in the control of UC, and it is important to pay attention to them in health decisions.

An Overview of the Public Health Challenges in Diagnosing and Controlling Human Foodborne Pathogens

Pathogens found in food are believed to be the leading cause of foodborne illnesses; and they are considered a serious problem with global ramifications. During the last few decades, a lot of attention has been paid to determining the microorganisms that cause foodborne illnesses and developing new methods to identify them. Foodborne pathogen identification technologies have evolved rapidly over the last few decades, with the newer technologies focusing on immunoassays, genome-wide approaches, biosensors, and mass spectrometry as the primary methods of identification. Bacteriophages (phages), probiotics and prebiotics were known to have the ability to combat bacterial diseases since the turn of the 20th century. A primary focus of phage use was the development of medical therapies; however, its use quickly expanded to other applications in biotechnology and industry. A similar argument can be made with regards to the food safety industry, as diseases directly endanger the health of customers. Recently, a lot of attention has been paid to bacteriophages, probiotics and prebiotics most likely due to the exhaustion of traditional antibiotics. Reviewing a variety of current quick identification techniques is the purpose of this study. Using these techniques, we are able to quickly identify foodborne pathogenic bacteria, which forms the basis for future research advances. A review of recent studies on the use of phages, probiotics and prebiotics as a means of combating significant foodborne diseases is also presented. Furthermore, we discussed the advantages of using phages as well as the challenges they face, especially given their prevalent application in food safety.

Epoxy Triglyceride Enhances Intestinal Permeability via Caspase-1/NLRP3/GSDMD and cGAS-STING Pathways in Dextran Sulfate Sodium-Induced Colitis Mice

Oxidized triglyceride monomers are the main cytotoxic products of deep-frying oil. However, its impact on the intestinal barrier, the first health guardian, remains unknown. In this study, HPLC-MS/MS analysis revealed that the epoxy group is the main oxidation product, indicating that it may be the main cytotoxic factor. Therefore, 1-9,10-epoxystearic ester, 2,3-dioleic acid (EGT) and glycerol trioleate (GT) were used to reveal the effect of the epoxy group on the intestinal barrier of dextran sulfate sodium-induced colitis. Characteristics analysis showed that EGT could aggravate intestinal damage. The relative mRNA expression analysis suggested that EGT could activate Caspase-1/NLRP3/GSDMD, thereby inducing pyroptosis. The proinflammatory cytokines activated by pyroptosis and the cGAS-STING pathway were released through the pores, thus inducing the disintegration of the tight junction between the intestinal epithelial cells and enhancing intestinal permeability. Metabonomics further confirmed that EGT can change the composition and content of phospholipids on the cell membrane, indicating the morphological changes of the intestinal epithelial cell membrane. In conclusion, this study highlights that EGT induced intestinal dysfunction via Caspase-1/NLRP3/GSDMD and cGAS-STING pathways.

Determination Methods of the Risk Factors in Food Based on Nanozymes: A Review

Food safety issues caused by foodborne pathogens, chemical pollutants, and heavy metals have aroused widespread concern because they are closely related to human health. Nanozyme-based biosensors have excellent characteristics such as high sensitivity, selectivity, and cost-effectiveness and have been used to detect the risk factors in foods. In this work, the common detection methods for pathogenic microorganisms, toxins, heavy metals, pesticide residues, veterinary drugs, and illegal additives are firstly reviewed. Then, the principles and applications of immunosensors based on various nanozymes are reviewed and explained. Applying nanozymes to the detection of pathogenic bacteria holds great potential for real-time evaluation and detection protocols for food risk factors.

Fumonisin B1 induced intestinal epithelial barrier damage through endoplasmic reticulum stress triggered by the ceramide synthase 2 depletion

Fumonisin B₁ (FB₁) contamination in feed is of great concern nowadays. The intestine would be the first line when FB₁-contaminated food or feed was ingested. However, the intestinal toxicity and mechanism of FB₁ have rarely been studied. In this study, we found that FB₁ inhibited cell viability, and promoted the severe release of lactate dehydrogenase. Meantime, FB₁ destroyed the intestinal physical barrier by reducing the expressions of tight junctions. And FB₁ induced excessive production of cytokines like tumor necrosis factor-α, resulting in damage to the intestinal immunological barrier. Furthermore, we observed that FB₁ preferentially inhibited the expressions of ceramide synthase 2 (CerS2) and upregulated the expression of endoplasmic reticulum (ER) stress markers. The siRNA-mediated knockdown of CerS2 and CerS2 overexpression proved that CerS2 depletion induced by FB₁ triggered ER stress, which then destructed the intestinal barrier. FB₁-induced intestinal impairment could be restored by CerS2 over-expression or 4-Phenylbutyric acid (ER stress inhibitor). Overall, our findings demonstrated intestinal toxicity and potential mechanism of FB₁, and the intestinal impairment risk posed by FB₁ must be taken seriously.

Deep-frying oil induces cytotoxicity, inflammation and apoptosis on intestinal epithelial cells

BACKGROUND

Deep-frying oil has been found to cause inflammatory bowel disease (IBD). However, the molecular mechanism of the effect of deep-frying palm oil on IBD still remains undetermined.

RESULTS

In the present study, bioinformatics and cell biology were used to investigate the functions and signal pathway enrichments of differentially expressed genes. The bioinformatics analysis of three original microarray datasets (GSE73661, GSE75214 and GSE126124) in the NCBI-Gene Expression Omnibus database showed 17 down-regulated genes (logFC < 0) and 2 up-regulated genes (logFC > 0) existed in the enteritis tissue. Meanwhile, pathway enrichment and protein-protein interaction network analysis suggested that IBD is relevant to cytotoxicity, inflammation and apoptosis. Furthermore, Caco-2 cells were treated with the main oxidation products of deep-frying oil-total polar compounds (TPC) and its components (polymerized triglyceride, oxidized triglycerides and triglyceride degradation products) isolated from deep-frying oil. The flow cytometry experiment revealed that TPC and its components could induce apoptosis, especially for oxidized triglyceride. A quantitative polymerase chain reaction analysis demonstrated that TPC and its component could induce Caco-2 cell apoptosis through AQP8/CXCL1/TNIP3/IL-1.

CONCLUSION

The present study provides fundamental knowledge for understanding the effects of deep-frying oils on the cytotoxic and inflammatory of Caco-2 cells, in addition to clarifying the molecular function mechanism of deep-frying oil in IBD. © 2021 Society of Chemical Industry.

Two New Sulfate-Modified Dibenzopyrones With Anti-foodborne Bacteria Activity From Sponge-Derived Fungus Alternaria sp. SCSIOS02F49

At present, foodborne diseases (FBDs) caused by bacteria are gradually increasing every year, and the development of new antibiotics is an urgent necessity for human beings. To find novel antibacterial compounds, three sponge-derived fungal strains (SCSIOS02F40, F46, and F49) were investigated. As a result, Alternaria sp. SCSIOS02F49 was selected for investigation on its secondary metabolites because its ethyl acetate (EtOAc) extract of potato dextrose broth (PDB) culture showed rich metabolites and strong antibacterial activity. Two new dibenzopyrones with rare sulfate group (1–2), together with 10 known compounds (3–12), were isolated from the Alternaria sp. SCSIOS02F49. Their structures were confirmed by nuclear magnetic resonance (NMR), mass spectrometry (MS) data, and comparison with data from the relevant literature. Almost all compounds showed moderate inhibitory activity against eight foodborne bacteria (FBB) with minimum inhibitory concentration (MIC) values in the range of 15.6–250 μg/ml, and minimum bactericidal concentration (MBC) values in the range of 31.3–250 μg/ml. The antibacterial mechanism of compound 1 was preliminarily investigated using growth curves, scanning electron microscopy (SEM), and flow cytometry (FCM), which revealed that compound 1 altered the external structure of Staphylococcus aureus and caused the rupture or deformation of the cell membranes. This research provides lead compounds for the development of new antibiotics or microbial preservatives.

A population-based survey of the prevalence of self-reported acute gastrointestinal illness in Zhejiang Province, China

Acute gastrointestinal illness (AGI) is a prevalent public health concern worldwide. This study investigated the magnitude, distribution and burden of self-reported AGI among residents of Zhejiang Province, China. A face-to-face household survey was conducted using a multi-stage stratified random sampling method in 10 counties in Zhejiang Province between July 2018 and June 2019. In total, 12,021 participants were recruited. The prevalence of AGI 28 days after standardization was 1.8% (95% confidence interval (CI), 1.6–2.1), with an incidence rate of 0.24 episodes of AGI per person-year and an estimated 14 million cases of AGI in Zhejiang Province. Univariate and multivariable analyses showed a higher AGI prevalence among people who performed housework and were unemployed in summer and autumn among respondents living in western or northern cities (p < 0.05). More than 50% of AGI cases were attributed to the consumption of contaminated food. The disease burden caused by AGI in Zhejiang Province was approximately 975 million Chinses yuan (CNY). These results indicated that the disease burden of AGI in Zhejiang Province should be addressed and highlights the need for an improved active surveillance system of foodborne diseases to assess the impact of AGI on society and health.

Deoxynivalenol photocatalytic detoxification products alleviate intestinal barrier damage and gut flora disorder in BLAB/c mice

Deoxynivalenol (DON), a trichothecene mycotoxin, is one of the most globally prevalent mycotoxins mainly produced by Fusarium species. DON exposure can cause spectrum of symptoms such as nausea, vomiting, gastroenteritis, growth retardation, immunosuppression, and intestinal flora disorders in humans and animals. Therefore, the implication of DON degradation technology is of great significance for food safety. Recently, photocatalytic degradation technology has been applied for DON control. However, the toxicity of the intermediates identified in the degradation process was often ignored. In this work, based on previous successful degradation of DON and evaluation of the in vitro toxicity of DON photocatalytic detoxification products (DPDPs), we further studied the in vivo toxicity of DPDPs and mainly explored their effects on intestinal barrier function and intestinal flora in mice. The results demonstrated that the DPDPs treated with photocatalyst for 120 min effectively increased the expression of intestinal tight junction proteins and improved the disorder of gut flora. Meanwhile, compared with DON-exposed mice, the DPDPs reduced the level of inflammation and oxidative stress of intestinal tissue, and improved growth performance, enterohepatic circulation, energy metabolism, and autonomic activity. All the results indicated that the toxicity of the DPDPs irradiated for 120 min was much lower than that of DON or even nontoxic. Therefore, we hope that this photocatalytic degradation technology can be used as a promising tool for the detoxification of mycotoxins.