Individual and combined cytotoxicity assessment of zearalenone with ochratoxin A or α-zearalenol by full factorial design

Occurrence of the two major regulated mycotoxins, ochratoxin A and fumonisin B1, in cereal and cereal-based products in Europe and toxicological effects: A review

Among cereal contaminants, mycotoxins are of concern due to their importance in terms of food and feed safety. The difficulty in establishing a diagnosis for mycotoxicosis relies on the fact that the effects are most often subclinical for chronic exposure and the most common scenario is multi-contamination by various toxins. Mycotoxin co-occurrence is a major food safety concern as additive or even synergic toxic impacts may occur, but also regarding current regulations as they mainly concern individual mycotoxin levels in specific foods and feed in the food chain. However, due to the large number of possible mycotoxin combinations, there is still limited knowledge on co-exposure toxicity data, which depends on several parameters. In this context, this systematic review aims to provide an overview of the toxic effects of two regulated mycotoxins, namely ochratoxin A and fumonisin B1. This review focused on the 2012-2022 period and analysed the occurrence in Europe of the selected mycotoxins in different food matrices (cereals and cereal-derived products), and their toxic impact, alone or in combination, on in vitro intestinal and hepatic human cells. To better understand and evaluate the associated risks, further research is needed using new approach methodologies (NAM), such as in vitro 3D models. KEY CONTRIBUTION: Cereals and their derived products are the most important food source for humans and feed for animals worldwide. This manuscript is a state of the art review of the literature over the last ten years on ochratoxin A and fumonisin B1 mycotoxins in these products in Europe as well as their toxicological effects, alone and in combination, on human cells. Future perspectives and some challenges regarding the assessment of toxicological effects of mycotoxins are also discussed.

Efficacy of a multicomponent binding agent against combined exposure to zearalenone and ochratoxin A in weaned pigs

Introduction

The study aimed to evaluate the efficacy of a novel multicomponent substance against combined exposure to the mycotoxins zearalenone (ZEN) and ochratoxin A (OTA) in weaned piglets.

Methods

In total, 60 piglets at the age of 28 days were equally allocated to four experimental groups (A-D), consisting of eight female and seven male piglets each (15 animals per group, for a total trial duration of 42 days). Animals from group A received typical weaner feed without mycotoxins or the test product [multicomponent mycotoxin detoxifying agent (MMDA)]. Group B animals received the same weaner feed contaminated with 0.992 mg ZEN/kg feed and 0.531 mg OTA/kg feed without the addition of the MMDA. Animals in group C received the same contaminated feed as group B with the addition of 1.5 g MMDA/kg feed, whereas group D received the same feed as group B with the inclusion of 3 g MMDA/kg feed. Clinical signs and performance parameters [body weight (BW), average daily weight gain (ADWG), and feed conversion ratio (FCR)] were evaluated, while mycotoxin residues were also assessed in the liver and kidney tissues.

Results

Findings showed improved FCR in the group that received the greatest dose of the test product (3 g MMDA/kg feed) compared to the group that received the lower dose (1.5 g MMDA/kg feed). A few hematological and biochemical parameters were slightly altered, predominantly within normal limits. The residue analysis demonstrated a reduction of OTA in liver samples, a-ZEL in the liver and total tested samples, and a total of ZEN and metabolite contents in all samples of the group that received the greatest MMDA dose in comparison to the group that received the toxins without the addition of the test product.

Discussion

Therefore, a positive effect of the MMDA at the greatest dosage regime on reducing bioavailability and tissue deposition of ZEN and OTA, with a particularly positive effect on FCR in weaned pigs, is suggested under concurrent ZEN and OTA exposure in vivo.

Effectiveness of beetroot extract in SH-SY5Y neuronal cell protection against Fumonisin B1, Ochratoxin A and its combination

Fumonisin B1 (FB1) and ochratoxin A (OTA) are fungal metabolites of worldwide concern because of their effect on human and animal health, as both have been classified by IARC as possible carcinogens (Group 2B). Beetroot is a source of dietary fiber, folic acid, and vitamin C, and some studies have demonstrated their antioxidant activity. Therefore, this work presents the cytoprotective effect of beetroot extract (BRE) on a neuroblastoma cell line (SH-SY5Y cells) exposed to FB1, OTA, and its combination. Cytotoxicity was studied by the MTT ([3-4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay, for 24 h and 48 h. Simultaneous treatment and pre-treatment strategies were tested with 1:512-1:2 and 1:0 dilutions of BRE, with a concentration range from 0.4 to 100 μM of FB1 and from 0.19 to 50 μM of OTA. IC₅₀ values of 5.8 μM and 9.1 μM at 24 h and 48 h, respectively were obtained for OTA while no cytotoxic effect was detected at the concentrations tested for FB1. Cytoprotection with increased viability was obtained when the simultaneous BRE + OTA strategy was performed. Finally, better protection was observed in the pretreatment strategy in which cells were exposed 24 h previously to BRE, compared to that shown in the simultaneous assay.

Cytotoxicity of Mycotoxins and Their Combinations on Different Cell Lines: A Review

Mycotoxins are secondary metabolites of molds and mainly produced by species of the genera Aspergillus, Penicillium and Fusarium. They can be synthesized on the field, during harvest as well as during storage. They are fairly stable compounds and difficult to remove. Among several hundreds of mycotoxins, according to the WHO, ochratoxin A, aflatoxins, zearalenone, deoxynivalenol, patulin, fumonisins as well as T-2 and HT-2 toxins deserve special attention. Cytotoxicity is one of the most important adverse properties of mycotoxins and is generally assessed via the MTT assay, the neutral red assay, the LDH assay, the CCK-8 assay and the ATP test in different cell lines. The apoptotic cell ratio is mainly assessed via flow cytometry. Aside from the assessment of the toxicity of individual mycotoxins, it is important to determine the cytotoxicity of mycotoxin combinations. Such combinations often exhibit stronger cytotoxicity than individual mycotoxins. The cytotoxicity of different mycotoxins often depends on the cell line used in the experiment and is frequently time- and dose-dependent. A major drawback of assessing mycotoxin cytotoxicity in cell lines is the lack of interaction typical for complex organisms (for example, immune responses).

Anti-inflammatory actions of acetate, propionate, and butyrate in fetal mouse jejunum cultures ex vivo and immature small intestinal cells in vitro

Necrotizing enterocolitis (NEC) is an intestinal disease that frequently occurs in premature infants. Presently, there is no effective therapy for NEC. Therefore, the key to reduce the incidence rate of NEC is to take effective intervention measures as early as possible. Short-chain fatty acids (SCFAs) (acetate, propionate, and butyrate), the principal terminal products of enterobacteria fermentation, play anti-inflammatory actions in mature intestinal cells. However, few studies focus on their roles in immature intestine. Here, we evaluated the anti-inflammatory actions of SCFAs ex vivo with ICR fetal mouse jejunum cultures and explored the potential anti-inflammatory regulators through RNA-seq and then verified them in vitro with human fetal small intestinal epithelial FHs 74 Int cells. In this study, we found that acetate, propionate, and butyrate decreased IL-1β-induced production of CXCL2 ex vivo and IL-8 and IL-6 in vitro significantly (p < .05). Furthermore, the inhibitors of NF-κB p65, JNK1/2, and ERK1/2 pathways, which were selected from RNA-seq and depressed by SCFAs, also significantly decreased IL-8 and IL-6 productions induced by IL-1β (p < .05). Therefore, our results showed that acetate, propionate, and butyrate ameliorated the fetal small intestine inflammatory response induced by IL-1β through inhibiting ERK1/2 pathway; NF-κB p65, JNK1/2, and ERK1/2 pathways; or NF-κB p65 and ERK1/2 pathways, respectively. These findings suggested that SCFAs may be a new therapy agent for NEC.

Determination of zearalenone in raw milk from different provinces of Ecuador

Background and Aim:

Zearalenone (ZEA) is a mycotoxin from the fungus Fusarium. ZEA can adopt a similar configuration to 17b-estradiol and other natural estrogens. Problems in the reproductive function of humans and animals have been reported for ZEA and its metabolites. This study aimed to determine ZEA in raw milk produced in representative milk production areas in Ecuador.

Materials and Methods:

A total of 209 samples were obtained in April and November 2019 (rainy season) and June and August 201ue wa9 (dry season). A competitive enzyme-linked immunosorbent assay techniqs used to detect ZEA concentrations.

Results:

ZEA was determined in 99.5% (208 of 209) of the samples; however, all samples were below the maximum limits allowed (0.03-1 mg/L) in food for direct human consumption according to the Food and Agriculture Organization and European legislations. The mean (range) concentration was 0.0015 (0-0.0102) mg/L. The results did not vary significantly (p≥0.05) by cantons, provinces, weather, climate regions, types of producers, and production systems according to Wilcoxon and Kruskal–Wallis non-parametric tests. There were significant differences only between the months under study (p≤0.05).

Conclusion:

ZEA in raw milk from Ecuador does not represent a threat to public health. However, it is recommended to continue analyzing ZEA due to its presence in milk. It could also be present with other mycotoxins that cause harmful synergistic and additive effects to consumers.

In Vitro Evaluation of the Individual and Combined Cytotoxic and Estrogenic Effects of Zearalenone, Its Reduced Metabolites, Alternariol, and Genistein

Mycotoxins are toxic metabolites of filamentous fungi. Previous studies demonstrated the co-occurrence of Fusarium and Alternaria toxins, including zearalenone (ZEN), ZEN metabolites, and alternariol (AOH). These xenoestrogenic mycotoxins appear in soy-based meals and dietary supplements, resulting in the co-exposure to ZEN and AOH with the phytoestrogen genistein (GEN). In this study, the cytotoxic and estrogenic effects of ZEN, reduced ZEN metabolites, AOH, and GEN are examined to evaluate their individual and combined impacts. Our results demonstrate that reduced ZEN metabolites, AOH, and GEN can aggravate ZEN-induced toxicity; in addition, the compounds tested exerted mostly synergism or additive combined effects regarding cytotoxicity and/or estrogenicity. Therefore, these observations underline the importance and the considerable risk of mycotoxin co-exposure and the combined effects of mycoestrogens with phytoestrogens.

Individual and Combined Effect of Zearalenone Derivates and Beauvericin Mycotoxins on SH-SY5Y Cells

Beauvericin (BEA) and zearalenone derivatives, α-zearalenol (α-ZEL), and β-zearalenol (β-ZEL), are produced by several Fusarium species. Considering the impact of various mycotoxins on human's health, this study determined and evaluated the cytotoxic effect of individual, binary, and tertiary mycotoxin treatments consisting of α-ZEL, β-ZEL, and BEA at different concentrations over 24, 48, and 72 h on SH-SY5Y neuronal cells, by using the MTT assay (3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazoliumbromide). Subsequently, the isobologram method was applied to elucidate if the mixtures produced synergism, antagonism, or additive effects. Ultimately, we determined the amount of mycotoxin recovered from the media after treatment using liquid chromatography coupled with electrospray ionization-quadrupole time-of-flight mass spectrometry (LC-ESI-qTOF-MS). The IC50 values detected at all assayed times ranged from 95 to 0.2 μM for the individual treatments. The result indicated that β-ZEL was the most cytotoxic mycotoxin when tested individually. The major effect detected for all combinations assayed was synergism. Among the combinations assayed, α-ZEL + β-ZEL + BEA and α-ZEL + BEA presented the highest cytotoxic potential with respect to the IC value. At all assayed times, BEA was the mycotoxin recovered at the highest concentration in individual form, and β-ZEL + BEA was the combination recovered at the highest concentration.

Assessing the Effect of Mycotoxin Combinations: Which Mathematical Model Is (the Most) Appropriate?

In the past decades, many studies have examined the nature of the interaction between mycotoxins in biological models classifying interaction effects as antagonisms, additive effects, or synergisms based on a comparison of the observed effect with the expected effect of combination. Among several described mathematical models, the arithmetic definition of additivity and factorial analysis of variance were the most commonly used in mycotoxicology. These models are incorrectly based on the assumption that mycotoxin dose-effect curves are linear. More appropriate mathematical models for assessing mycotoxin interactions include Bliss independence, Loewe’s additivity law, combination index, and isobologram analysis, Chou-Talalays median-effect approach, response surface, code for the identification of synergism numerically efficient (CISNE) and MixLow method. However, it seems that neither model is ideal. This review discusses the advantages and disadvantages of these mathematical models.