Mycotoxin Interactions along the Gastrointestinal Tract: In Vitro Semi-Dynamic Digestion and Static Colonic Fermentation of a Contaminated Meal

Danshen polysaccharides alleviate AFB1 induced Jejunal injury

AFB1 is a common foodborne toxin known for its potent carcinogenicity. Danshen polysaccharide (DSP) is an active ingredient of Danshen, which has been demonstrated to possess support intestinal homeostasis and anti-inflammatory activities. We utilized New Zealand White rabbits as an animal model to examine the impact of co-exposure to DSP and AFB1 on the intestines, as well as their underlying mechanisms. The results indicate that DSP elevated the abundance of Oscillospira, Coprococcus, Alistipes, Akkermansia, Bacteroides, Odoribacter, Blautia and Parabacteroides, while decreased the abundance of Sutterella, and Desulfovibrio, correcting AFB1-induced intestinal microbiota dysbiosis and enhancing microbial diversity within the gut. Moreover, DSP reduced the levels of diamine oxidase (DAO), D-Lactate, and malondialdehyde (MDA), while upregulating the expression of total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), zonula occludens-1 (ZO-1), occludin, claudin-4, mucin-2 (MUC2), and secretory immunoglobulin A (sIgA), thereby alleviating the oxidative stress and intestinal barrier dysfunction induced by AFB1. DSP downregulated jejunal lipopolysaccharide (LPS) levels and the mRNA expression and proteins abundance of toll-like receptor 4 (TLR4), myeloiddifferentiationfactor 88 (MyD88), and nuclear factor kappa-B (NF-κB), thereby inhibiting the jejunal inflammation induced by AFB1. In summary, DSP alleviates AFB1-induced jejunal injury by remodeling the gut microbiota, bolstering antioxidant capabilities within the jejunum, fortifying the intestinal barrier, and suppressing the TLR4-mediated release of pro-inflammatory cytokines.

Grape pomace as a novel functional ingredient: Mitigating ochratoxin A bioaccessibility and unraveling cytoprotective mechanisms in vitro

Mycotoxins, secondary metabolites produced by molds, pose significant health risk through contamination of globally consumed cereals. Ochratoxin A (OTA), a prevalent mycotoxin in cereals, is associated with various health hazards, including immunotoxicity. This study explores the bioaccessibility of OTA in bread and its impact on the gastrointestinal barrier. A focus is placed on grape pomace (GP), a by-product of the wine industry, as a potential mitigator of OTA toxicity. Results demonstrate that GP reduces OTA bioaccessibility in the human gastrointestinal system from 94% to 81% at intestinal level, showing promise in limiting the absorption of the harmful toxin. Additionally, GP exhibits cytoprotective effects, enhancing cell viability and mitigating OTA-induced toxicity in both Caco-2 and Jurkat T cells. In view of the above, to understand the mechanisms by which OTA exhibits its toxic effects, flow cytometry was chosen as the main technique for the analysis of cell cycle, reactive oxygen species levels and mitochondrial parameters. Cytofluorimetric evaluation indicates GP's potential in limiting OTA-induced damage at cellular level. The study suggests that GP could serve as functional ingredient to reduce mycotoxin bioaccessibility and toxicity in cereal-based foods, offering a novel and promising approach to enhance food safety and protect public health. The finding highlights the potential of utilizing grape pomace in food formulations to mitigate mycotoxin contamination, providing a valuable contribution to the ongoing efforts to ensure the safety of globally consumed cereal products.

A DNA tetrahedral scaffolds-based electrochemical biosensor for simultaneous detection of AFB1 and OTA

Herein, a bifunctional electrochemical biosensor based on the DNA tetrahedral scaffolds (TDNs) was proposed, OTA@TDNs and AFB1@TDNs were adopted for electrochemical signal output in response to OTA and AFB1 concentration, simultaneously. In order to increase the conductivity of the biosensor, highly porous gold (HPG) was loaded on electrode surface by pulse electrodeposition. Under optimal conditions, the PFc displayed a linear range with AFB1 concentration between 0.05 ∼ 360 ng·mL-1 with the LOD of 3.5 pg·mL-1. And the PMB selective and sensitive responses to OTA are achieved with a linear range of 0.05 ∼ 420 ng·mL-1 and a LOD of 2.4 pg·mL-1. This biosensor has high sensitivity, selectivity and stability for OTA and AFB1 detection in peanut samples. The approach streamlines the experimental procedure, leading to significantly improve the detection efficiency of mycotoxins. Collectively, this method suggest a novel approach for the detection and monitoring of OTA and AFB1 in food sample.

The intestinal microbiota as mediators between dietary contaminants and host health

The gut microbiota sit at an important interface between the host and the environment, and are exposed to a multitude of nutritive and non-nutritive substances. These microbiota are critical to maintaining host health, but their supportive roles may be compromised in response to endogenous compounds. Numerous non-nutritive substances are introduced through contaminated foods, with three common groups of contaminants being bisphenols, phthalates, and mycotoxins. The former contaminants are commonly introduced through food and/or beverages packaged in plastic, while mycotoxins contaminate various crops used to feed livestock and humans alike. Each group of contaminants have been shown to shift microbial communities following exposure; however, specific patterns in microbial responses have yet to be identified, and little is known about the capacity of the microbiota to metabolize these contaminants. This review characterizes the state of existing research related to gut microbial responses to and biotransformation of bisphenols, phthalates, and mycotoxins. Collectively, we highlight the need to identify consistent, contaminant-specific responses in microbial shifts, whether these community alterations are a result of contaminant effects on the host or microbiota directly, and to identify the extent of contaminant biotransformation by microbiota, including if these transformations occur in physiologically relevant contexts.

Gut Microbiota and Derived Short-Chain Fatty Acids Are Linked to Evolution of Heart Failure Patients

There is a lack of direct evidence regarding gut microbiota dysbiosis and changes in short-chain fatty acids (SCFAs) in heart failure (HF) patients. We sought to assess any association between gut microbiota composition, SCFA production, clinical parameters, and the inflammatory profile in a cohort of newly diagnosed HF patients. In this longitudinal prospective study, we enrolled eighteen newly diagnosed HF patients. At admission and after 12 months, blood samples were collected for the assessment of proinflammatory cytokines, monocyte populations, and endothelial dysfunction, and stool samples were collected for analysis of gut microbiota composition and quantification of SCFAs. Twelve months after the initial HF episode, patients demonstrated improved clinical parameters and reduced inflammatory state and endothelial dysfunction. This favorable evolution was associated with a reversal of microbiota dysbiosis, consisting of the increment of health-related bacteria, such as genus Bifidobacterium, and levels of SCFAs, mainly butyrate. Furthermore, there was a decrease in the abundance of pathogenic bacteria. In vitro, fecal samples collected after 12 months of follow-up exhibited lower inflammation than samples collected at admission. In conclusion, the favorable progression of HF patients after the initial episode was linked to the reversal of gut microbiota dysbiosis and increased SCFA production, particularly butyrate. Whether restoring butyrate levels or promoting the growth of butyrate-producing bacteria could serve as a complementary treatment for these patients deserves further studies.

Total Flavonoids of Rhizoma Drynariae Mitigates Aflatoxin B1-Induced Liver Toxicity in Chickens via Microbiota-Gut-Liver Axis Interaction Mechanisms

Aflatoxin B1 (AFB1) is a common mycotoxin that widely occurs in feed and has severe hepatotoxic effects both in humans and animals. Total flavonoids of Rhizoma Drynaria (TFRD), a traditional Chinese medicinal herb, have multiple biological activities and potential hepatoprotective activity. This study investigated the protective effects and potential mechanisms of TFRD against AFB1-induced liver injury. The results revealed that supplementation with TFRD markedly lessened broiler intestinal permeability by increasing the expression of intestinal tight junction proteins, as well as correcting the changes in gut microbiota and liver damage induced by AFB1. Metabolomics analysis revealed that the alterations in plasma metabolites, especially taurolithocholic acid, were significantly improved by TFRD treatment in AFB1-exposed chickens. In addition, these metabolites were closely associated with [Ruminococcus], ACC, and GPX1, indicating that AFB1 may cause liver injury by inducing bile acid metabolism involving the microbiota–gut–liver axis. We further found that TFRD treatment markedly suppressed oxidative stress and hepatic lipid deposition, increased plasma glutathione (GSH) concentrations, and reversed hepatic ferroptosis gene expression. Collectively, these findings indicate that ferroptosis might contribute to the hepatotoxicity of AFB1-exposed chickens through the microbiota–gut–liver axis interaction mechanisms; furthermore, TFRD was confirmed as an herbal extract that could potentially antagonize mycotoxins detrimental effects.

Electrochemical aptasensor based on the target-induced strand displacement strategy-driven for T-2 toxin detection

Herein, an aptasensor based on target-induced strand displacement (TISD) strategy was developed for sensitive detection of T-2 toxin. Gold nanoparticles@ aminated manganese dioxide (AuNPs@NH₂-MnO₂) exhibited excellent electrical conductivity and provided more binding sites for aptamer (Apt). Besides, polyethyleneimine-reduced graphene oxide/gold‑platinum core-shell nanorods composites (PEI-rGO/Pt@Au NRs) were used to be carriers for signaling tags, as their sufficiently large specific surface area improved the loading capacity for signal molecules. In the presence of T-2, the Apt sequence was more inclined to form an Apt-T-2 complex, and the cDNA was displaced from the Apt-cDNA duplex, while the signal tag was released, resulting in a weakened MB signal, differential pulse voltammetry (DPV) was used to record the signal change. Under optimal conditions, the signal response of the constructed electrochemical aptasensor exhibited a good linear relationship with the concentration of T-2. The detection limit was 8.74 × 10^-7 ng mL^-1over a wide range of concentration from 5 × 10^-6 ng mL^-1 to 5 ng mL^-1. Furthermore, the proposed aptasensor had excellent specificity, good stability and can be well applied to the detection of real samples. It provided a new avenue for the research and development of sensitive aptasensors in food detection and analysis.

Modified Mycotoxins, a Still Unresolved Issue

Mycotoxins are toxic secondary metabolites produced by filamentous microfungi on almost every agricultural commodity worldwide. After the infection of crop plants, mycotoxins are modified by plant enzymes or other fungi and often conjugated to more polar substances, like sugars. The formed—often less toxic—metabolites are stored in the vacuole in soluble form or bound to macromolecules. As these substances are usually not detected during routine analysis and no maximum limits are in force, they are called modified mycotoxins. While, in most cases, modified mycotoxins have lower intrinsic toxicity, they might be reactivated during mammalian metabolism. In particular, the polar group might be cleaved off (e.g., by intestinal bacteria), releasing the native mycotoxin. This review aims to provide an overview of the critical issues related to modified mycotoxins. The main conclusion is that analytical aspects, toxicological evaluation, and exposure assessment merit more investigation.

Application of an In Vitro Digestion Model for Wheat and Red Beetroot Bread to Assess the Bioaccessibility of Aflatoxin B1, Ochratoxin A and Zearalenone and Betalains

Nowadays, the bakery industry includes different bioactive ingredients to enrich the nutritional properties of its products, such as betalains from red beetroot (Beta vulgaris). However, cereal products are considered a major route of exposure to many mycotoxins, both individually and in combination, due to their daily consumption, if the cereals used contain these toxins. Only the fraction of the contaminant that is released from the food is bioaccessible and bioavailable to produce toxic effects. Foods with bioactive compounds vary widely in chemical structure and function, and some studies have demonstrated their protective effects against toxics. In this study the bioaccessibility and bioavailability of three legislated mycotoxins (AFB₁, OTA and ZEN), individual and combined, in two breads, one with wheat flour and the other with wheat flour enriched with 20% Beta vulgaris, were evaluated. Bioaccessibility of these three mycotoxins from wheat bread and red beet bread enriched individually at 100 ng/g was similar between the breads: 16% and 14% for AFB1, 16% and 17% for OTA and 26% and 22% for ZEN, respectively. Whereas, when mycotoxins were co-present these values varied with a decreasing tendency: 9% and 15% for AFB1, 13% and 9% for OTA, 4% and 25% for ZEN in wheat bread and in red beet bread, respectively. These values reveal that the presence of other components and the co-presence of mycotoxins can affect the final bioavailability; however, it is necessary to assess this process with in vivo studies to complete the studies.

Combined Toxicity Evaluation of Ochratoxin A and Aflatoxin B1 on Kidney and Liver Injury, Immune Inflammation, and Gut Microbiota Alteration Through Pair-Feeding Pullet Model

Ochratoxin A (OTA) and aflatoxin B1 (AFB1) are often co-contaminated, but their synergistic toxicity in poultry is limitedly described. Furthermore, the traditional ad libitum feeding model may fail to distinguish the specific impact of mycotoxins on the biomarkers and the indirect effect of mildew on the palatability of feed. A pair-feeding model was introduced to investigate the specific effect and the indirect effect of the combined toxicity of OTA and AFB1, which were independent and dependent on feed intake, respectively. A total of 180 one-day-old pullets were randomly divided into 3 groups with 6 replicates, and each replicate contained 10 chicks. The control group (Group A) and the pair-feeding group (Group B) received the basal diet without mycotoxin contamination. Group C was administrated with OTA- and AFB1-contaminated feed (101.41 μg/kg of OTA + 20.10 μg/kg of AFB1). The scale of feeding in Group B matched with the feed intake of Group C. The trial lasted 42 days. Compared with the control group, co-contamination of OTA and AFB1 in feed could adversely affect the growth performance (average daily feed intake (ADFI), body weight (BW), average daily weight gain (ADG), feed conversion ratio (FCR), and shank length (SL)), decrease the relative weight of the spleen (p < 0.01), and increase the relative weight of the kidney (p < 0.01). Moreover, the reduction of feed intake could also adversely affect the growth performance (BW, ADG, and SL), but not as severely as mycotoxins do. Apart from that, OTA and AFB1 also activated the antioxidative and inflammation reactions of chicks, increasing the level of catalase (CAT), reactive oxygen species (ROS), and interleukin-8 (IL-8) while decreasing the level of IL-10 (p < 0.01), which was weakly influenced by the feed intake reduction. In addition, OTA and AFB1 induced histopathological changes and apoptosis in the kidney and liver as well as stimulated the growth of pernicious bacteria to cause toxic effects. There were no histopathological changes and apoptosis in the kidney and liver of the pair-feeding group. The combined toxicity of OTA and AFB1 had more severe effects on pullets than merely reducing feed supply. However, the proper reduction of the feed intake could improve pullets’ physical health by enriching the bacteria Lactobacillus, Phascolarctobacterium, Bacteroides, Parabacteroides, and Barnesiella.