An in vitro investigation of endocrine disrupting effects of trichothecenes deoxynivalenol (DON), T-2 and HT-2 toxins

Estrogenic, androgenic, and genotoxic activities of zearalenone and deoxynivalenol in in vitro bioassays including exogenous metabolic activation

Zearalenone (ZEN) and deoxynivalenol (DON) and their derivatives are well-known mycotoxins, which can occur not only in crops but also in water bodies, including drinking water sources. In vitro bioassays can be used to detect biological effects of hazardous compounds in water. To this, when studying biological effects and toxicity in vitro, metabolism is important to consider. In this study, ZEN, α-zearalenol (α-ZEL), DON, 3-acetyl DON, and 15-acetyl DON were evaluated in vitro for hormone receptor-mediated effects (estrogen receptor [ER] and androgen receptor [AR]) and genotoxicity (micronucleus assay) in the presence of an exogenous metabolic activation system (MAS). The ER bioassay proved to be a highly sensitive method to detect low concentrations of the ZEN compounds (EC10 values of 31.4 pM for ZEN, 3.59 pM for α-ZEL) in aqueous solutions. In the presence of the MAS, reduced estrogenic effects were observed for both ZEN compounds (EC10 values of 6.47 × 103 pM for ZEN, 1.55 × 102 pM for α-ZEL). Of the DON compounds, only 3-acetyl DON was estrogenic (EC10 of 0.31 µM), and the effect was removed in the presence of the MAS. Anti-androgenic effects of the ZEN compounds and androgenic effects of the DON compounds were detected in the micromolar range. No induction of genotoxicity was detected for ZEN or DON in the presence of the MAS. Our study highlighted that inclusion of exogenous MAS is a useful tool to detect biological effects of metabolites in in vitro bioassays.

Development of an LC-MS/MS method for the determination of multiple mycotoxins in human urine

A sensitive liquid chromatography-tandem mass spectrometry method was developed for the determination of 17 mycotoxins in human urine. The method incorporates a two-step liquid-liquid extraction with ethyl acetate:acetonitrile (7:1), which had good extraction recovery. The LOQs of all mycotoxins ranged from 0.1 to 1 ng/mL. Intra-day accuracy ranged from 94 to 106%, and intra-day precision ranged from 1 to 12% for all mycotoxins. Inter-day accuracy and precision were 95-105% and 2-8%, respectively. The method was successfully applied to investigate the urine levels of 17 mycotoxins from 42 volunteers. Deoxynivalenol (DON, 0.97-9.88 ng/mL) was detected in 10 (24%) urine samples and zearalenone (ZEN, 0.13-1.11 ng/mL) in 2 (5%) urine samples.

Revealing the Role of Alternariol in the Local Steroidogenesis in Human Prostate Normal and Cancer Cells

The mycotoxin alternariol (AOH) can be found in food products infected by Alternaria spp. and is considered an endocrine-disruptive mycotoxin. The main mechanism of AOH toxicity is associated with DNA damage and modulation of the inflammation process. Still, AOH is considered as one of the emerging mycotoxins. In this study, we have evaluated how AOH might affect the local steroidogenesis process in the prostate, in both normal and cancer cells. We have found that AOH itself modulates the cell cycle, inflammation, and apoptosis, rather than the steroidogenesis process in prostate cancer cells; however, in the presence of another steroidogenic agent, the influence on steroidogenesis is significant. Therefore, this is the first study to report the effect of AOH on local steroidogenesis in normal and prostate cancer cells. We postulate that AOH might modulate the release of the steroid hormones and expression of the key components by interfering with the steroidogenic pathway and might be considered a steroidogenesis-altering agent.

Effect of the mycotoxin deoxynivalenol in combinational therapy with TRAIL on prostate cancer cells

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) is reported as a promising anti-cancer therapeutic target. Unfortunately, prostate cancer cells (PCa) are partially resistant to TRAIL-induced apoptosis limiting its therapeutic potential. The existing body of knowledge suggests that naturally produced compounds, such as mycotoxin deoxynivalenol (DON), might potentially sensitize cells to TRAIL treatment and improve the efficiency of therapy. Previously, we observed that DON induces oxidative stress and apoptosis in PCa cell lines. Thus we addressed here whether DON can sensitize PCa cells to TRAIL-induced apoptosis. Our data demonstrates that three out of four tested PCa cell lines pretreated with DON increased TRAIL-induced apoptosis detected with flow cytometry. This effect was associated with oxidative stress (LNCaP and DU-145 cell line) and elevated DNA damage (DU-145, LNCaP, and 22Rv1 cell lines). Next, in the animal model we inoculated PC tumor to SCKID mice followed by administration of DON intraperitoneally and/or TRIAL intravenously. During 21 days monitoring of tumor growth, the animals received 7 doses of DON, TRAIL, DON+TRAIL or control injections. No significant reduction in tumor mass was observed after combinational treatment of TRAIL and DON compared to 1 μg/kg of body weight DON treatment alone, which itself decreased the tumor growth. However, despite the lack of the TRAIL + DON effect, DON itself inducing apoptosis is an interesting compound worth investigating in the context of other combination therapies.

Lactoferrin Restores the Deoxynivalenol-Impaired Spermatogenesis and Blood-Testis Barrier Integrity via Improving the Antioxidant Capacity and Modifying the Cell Adhesion and Inflammatory Response

Deoxynivalenol (DON) is among the most prevalent contaminants in cereal crops and has been demonstrated to impair male spermatogenesis and induce oxidative stress, testicular apoptosis, and disruption of the blood-testis barrier (BTB). Lactoferrin (LF) is an iron-binding glycoprotein with multifunctions including anti-inflammation and antioxidation. Thus, this study aimed to investigate the effects of LF on the spermatogenesis and integrity of the BTB in DON-exposed mice. Thirty-two male mice were allotted to four groups for a 35-day feeding period: vehicle (basal diet), DON (12 mg/kg), LF (10 mg/d, p.o.), and DON + LF. The results showed that DON induced vacuolization of the spermatogenic epithelium, broke the adhesion junction between Sertoli cells and spermatids established by N-cadherin and induced testicular oxidative stress. LF administration restored sperm production, attenuated the DON-induced oxidative stress and reduced the breakages in adhesion junction. DON exposure enhanced the protein expression of occludin. Transcriptional profiling of the testis observed a disturbance in the expression profiles of cell adhesion and inflammatory response genes, and LF administration reversed these gene expressions. Furthermore, down-regulated signaling pathways, including the apical junction, TNFα signaling via NF-κB, and TGF-β in the DON group were observed. These were restored by LF. Enrichment analysis between DON + LF group and vehicle also confirmed the absence of these pathways. These findings indicated that LF eliminated the DON-induced detriment to spermatogenesis and cell connections between Sertoli cells and spermatids via improving antioxidant capacity and modifying the inflammatory response and cell adhesion genes.

Current Advances, Research Needs and Gaps in Mycotoxins Biomonitoring under the HBM4EU-Lessons Learned and Future Trends

Mycotoxins are natural metabolites produced by fungi that contaminate food and feed worldwide. They can pose a threat to human and animal health, mainly causing chronic effects, e.g., immunotoxic and carcinogenic. Due to climate change, an increase in European population exposure to mycotoxins is expected to occur, raising public health concerns. This urges us to assess the current human exposure to mycotoxins in Europe to allow monitoring exposure and prevent future health impacts. The mycotoxins deoxynivalenol (DON) and fumonisin B1 (FB1) were considered as priority substances to be studied within the European Human Biomonitoring Initiative (HBM4EU) to generate knowledge on internal exposure and their potential health impacts. Several policy questions were addressed concerning hazard characterization, exposure and risk assessment. The present article presents the current advances attained under the HBM4EU, research needs and gaps. Overall, the knowledge on the European population risk from exposure to DON was improved by using new harmonised data and a newly derived reference value. In addition, mechanistic information on FB1 was, for the first time, organized into an adverse outcome pathway for a congenital anomaly. It is expected that this knowledge will support policy making and contribute to driving new Human Biomonitoring (HBM) studies on mycotoxin exposure in Europe.

Adverse Effects of Fusarium Toxins in Ruminants: A Review of In Vivo and In Vitro Studies

With an increased knowledge of the mechanism of action of Fusarium mycotoxins, the concept that these substances are deleterious only for monogastric species is obsolete. Indeed, most mycotoxins can be converted into less toxic compounds by the rumen microflora from healthy animals. However, mycotoxin absorption and its conversion to more toxic metabolites, as well as their impact on the immune response and subsequently animal welfare, reproductive function, and milk quality during chronic exposure should not be neglected. Among the Fusarium mycotoxins, the most studied are deoxynivalenol (DON), zearalenone (ZEN), and fumonisins from the B class (FBs). It is remarkable that there is a paucity of in vivo research, with a low number of studies on nutrient digestibility and rumen function. Most of the in vitro studies are related to the reproductive function or are restricted to rumen incubation. When evaluating the production performance, milk yield is used as an evaluated parameter, but its quality for cheese production is often overlooked. In the present review, we summarize the most recent findings regarding the adverse effects of these mycotoxins with special attention to dairy cattle.

Toxic mechanisms of the trichothecenes T-2 toxin and deoxynivalenol on protein synthesis

The toxic mechanisms of trichothecenes, including T-2 toxin and deoxynivalenol (DON), are closely related with their effects on protein synthesis. Increasing lines of evidence show that T-2 toxin can reduce the levels of tight junction proteins, and nuclear factor erythroid 2-related factor 2 (Nrf2) by disrupting cellular barriers and the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) and Nrf2/heme oxygenase (HO)-1 pathways. Moreover, it can inhibit aggrecan synthesis, thus causing Kashin-Beck disease. Regarding type B trichothecene, DON inhibits activation marker and β-catenin synthesis by acting on immune cells and the wingless/integrated (Wnt) pathway; it also inhibits cell proliferation and immune surveillance. In addition, DON has been shown to destroy tight junctions, glucose transport, and tumor endothelial marker 8, thus disturbing intestinal function and changing cell migration. This review summarizes the inhibitory effects of the trichothecenes T-2 toxin and DON on different protein synthesis, while discussing their underlying mechanisms. Focus is given to the effects of these toxins on tight junctions, aggrecan, activation markers, and hormones including testosterone under the influence of steroidogenic enzymes. This review can extend the current understanding of the effects of trichothecenes on protein synthesis and help to further understand their toxic mechanisms.

A synergism of in silico and statistical approaches to discover new potential endocrine disruptor mycotoxins

Mycotoxins are secondary metabolites produced by pathogenic fungi. They are found in a variety of different products, such as spices, cocoa, and cereals, and they can contaminate fields before and/or after harvest and during storage. Mycotoxins negatively impact human and animal health, causing a variety of adverse effects, ranging from acute poisoning to long-term effects. Given a large number of mycotoxins (currently more than 300 are known), it is impossible to use in vitro/in vivo methods to detect the potentially harmful effects to human health of all of these. To overcome this problem, this work aims to present a new robust computational approach, based on a combination of in silico and statistical methods, in order to screen a large number of molecules against the nuclear receptor family in a cost and time-effective manner and to discover the potential endocrine disruptor activity of mycotoxins. The results show that a high number of mycotoxins is predicted as a potential binder of nuclear receptors. In particular, ochratoxin A, zearalenone, α- and β-zearalenol, aflatoxin B1, and alternariol have been shown to be putative endocrine disruptors chemicals for nuclear receptors.

The excavation of novel toxin-resistance proteins against trichothecenes toxins in Paramyrothecium roridum

Trichothecene toxins cause serious hazard towards human health and economical crops. However, there are no sufficient molecular strategies to reduce the hazard of trichothecene toxins. Thus it is urgent to exploit novel approaches to control the hazard of trichothecenes. In this study, four trichothecene toxin-resistance genes including mfs1, GNAT1, TRP1 and tri12 in Paramyrothecium roridum were excavated based on genome sequencing results, and then expressed in toxin-sensitive Saccharomyces cerevisiae BJ5464, the toxin resistance genes pdr5, pdr10 and pdr15 of which were firstly knocked out simultaneously by the introduction of TAA stop codon employing CRISPR/Cas9 system. Therefore, three novel hazardous toxin-resistance genes mfs1, GNAT1, TRP1 in P. roridum were firstly excavated by the co-incubation of DON toxin and toxin resistant genes-containing BJ5464 strains. The in vitro function and properties of novel toxin-resistance genes coding proteins including GNAT1, MFS1 and TRP1 were identified by heterologous expression and cellular location analysis as well as in vitro biochemical reaction. The excavation of novel trichothecene toxin-resistance genes provide novel molecular clues for controlling the harm of trichothecenes, meanwhile, this study will also pave a new way for the yield improvement of trichothecenes by heterologous expression to facilitate the development of trichothecenes as anti-tumor lead compounds.

Fusarium metabolites in maize from regions of Northern Serbia in 2016-2017

The main objective of this study was to determine the presence of Fusarium metabolites in maize samples collected from different regions of Northern Serbia (Bačka, Banat and Srem) during a period of two years (2016-2017). A total of 458 maize samples were analysed by liquid chromatography-tandem mass spectrometry. A total of 40 metabolites were detected, where 94% of the samples contained at least 5 metabolites. Fumonisins (including B₁, B₂, B₃ and B₄), moniliformin and bikaverin were the most frequent (80-98%) Fusarium metabolites in both years. Furthermore, in samples from 2016, fumonisin A₁ and A₂, deoxynivalenol, deoxynivalenol-3-glucoside, zearalenone, culmorin, 15-hydroxyculmorin, fusapyron, fusaproliferin and aurofusarin were detected with frequencies of 58-80%. Levels of certain Fusarium metabolites in 2016 were higher on average due to increased humidity when compared to 2017, which was characterised by warm and dry conditions.

In Vitro Analysis of Deoxynivalenol Influence on Steroidogenesis in Prostate

Deoxynivalenol (DON) is a type-B trichothecene mycotoxin produced by Fusarium species, reported to be the most common mycotoxin present in food and feed products. DON is known to affect the production of testosterone, follicle stimulating hormone (FSH) and luteinizing hormone (LH) in male rats, consequently affecting reproductive endpoints. Our previous study showed that DON induces oxidative stress in prostate cancer (PCa) cells, however the effect of DON on the intratumor steroidogenesis in PCa and normal prostate cells was not investigated. In this study human normal (PNT1A) and prostate cancer cell lines with different hormonal sensitivity (PC-3, DU-145, LNCaP) were exposed to DON treatment alone or in combination with dehydroepiandrosterone (DHEA) for 48 h. The results of the study demonstrated that exposure to DON alone or in combination with DHEA had a stimulatory effect on the release of estradiol and testosterone and also affected progesterone secretion. Moreover, significant changes were observed in the expression of genes related to steroidogenesis. Taken together, these results indicate that DON might affect the process of steroidogenesis in the prostate, demonstrating potential reproductive effects in humans.

Cyclic depsipeptide mycotoxin exposure may cause human endocrine disruption: Evidence from OECD in vitro stably transfected transcriptional activation assays

The presence of cyclic depsipeptide mycotoxins in foods and feedstuffs could potentially cause endocrine disrupting effects on humans and wildlife by their inhibition of active steroidogenesis. Therefore, we attempted to assess the human estrogen receptor (ER) and androgen receptor (AR) agonistic/antagonistic effects of representative cyclic depsipeptide mycotoxins, enniatin A1 (ENN A1), and enniatin B1 (ENN B1), by OECD Performand Based Test Guideline (PBTG) No.455, VM7Luc ER transcriptional activation (TA) assay and OECD TG No. 458, 22Rv1/MMTV_GR-KO AR TA assay. No tested cyclic depsipeptide mycotoxins were found to be ER and AR agonists in VM7Luc ER TA and 22Rv1/MMTV_GR-KO AR TA assays. On the other hand, ENN A1, and ENN B1 exhibited the ER and AR antagonistic effects with IC₃₀ and IC₅₀ values in both TA assays. These two cyclic depsipeptide mycotoxins, which were determined as ER and AR antagonists by two in vitro assays, bound to ERα, and AR. Then ENN A1, and ENN B1 inhibited the dimerization of ERα, and AR. These results, for the first time indicated that ENN A1, and ENN B1 could have potential endocrine disrupting effects mediated by interaction of ERα and AR using international standard testing methods to determine the potential endocrine disrupting chemical.

Occurrence, toxicity, production and detection of Fusarium mycotoxin: a review

Fusarium mycotoxin contamination of both foods and feeds is an inevitable phenomenon worldwide. Deoxynivalenol, nivalenol, zearalenone, T-2 toxin and fumonisin B1 are the most studied Fusarium mycotoxins. Co-contamination of mycotoxins has also been studied frequently. Fusarium mycotoxins occur frequently in foods at very low concentrations, so there is a need to provide sensitive and reliable methods for their early detection. The present review provides insight on the types, toxicology and occurrence of Fusarium mycotoxins. It further elucidates various detection methods of mycotoxin production from Fusarium strains, with a special focus on chromatographic and immunochemical techniques.

T-2 toxin downregulates LHCGR expression, steroidogenesis, and cAMP level in human cumulus granulosa cells

Our goals were to investigate whether environmentally relevant doses of T-2 toxin can affect human ovarian granulosa cells' function and to reveal the potential mechanism of T-2 toxin's action. Results showed that T-2 toxin strongly attenuated luteinizing hormone/choriogonadotropin receptor (LHCGR) mRNA expression in follicle-stimulating hormone (FSH)-stimulated human cumulus granulosa cells. Addition of human chorionic gonadotropin was not able to elicit maximal response of ovulatory genes amphiregulin, epiregulin, and progesterone receptor. T-2 toxin reduced mRNA levels of CYP19A1 and steroidogenic acute regulatory protein (STAR) and lowered FSH-stimulated estradiol and progesterone production. Mechanistic experiments demonstrated that T-2 toxin decreased FSH-stimulated cyclic adenosine monophosphate (cAMP) production. Addition of total PDE inhibitor 3-isobutyl-1-methylxanthine prevented T-2 toxin's action on LHCGR, STAR, and CYP19A1 mRNA expression in FSH-stimulated human cumulus granulosa cells. Furthermore, T-2 toxin partially decreased 8-bromoadenosine 3'5'-cyclic monophosphate (8-Br-cAMP)-stimulated LHCGR and STAR, but did not affect 8-Br-cAMP-stimulated CYP19A1 mRNA expression in human cumulus granulosa cells. Overall, our data indicate that environmentally relevant dose of T-2 toxin decreases steroidogenesis and ovulatory potency in human cumulus granulosa cells probably through activation of PDE, thus posing a significant risk for female fertility.

The effect of individual and mixtures of mycotoxins and persistent organochloride pesticides on oestrogen receptor transcriptional activation using in vitro reporter gene assays

The mycotoxins zearalenone (ZEN) and alpha-zearalenone (α-ZOL), which are common contaminants of agri-food products, are known for their oestrogenic potential. In addition to mycotoxins, food may also contain pesticides with oestrogenic properties such as 1,1,1-trichloro-2,2-bis(p-chlorophenyl) ethane (p,p'-DDT) and 1,1-dichloro-2,2-bis(p-chlorophenyl) ethylene (p,p'-DDE), raising the question on the potential effects of individual and combinations of these xeno-oestrogens on the action of natural oestrogens. The present study employed a mammalian reporter gene assay to assess the effects individual and binary combinations of these environmental and food-borne contaminants on oestrogen nuclear receptor (ER) transactivation. As expected, α-ZOL and ZEN exhibited the strongest oestrogenic potency (EC₅₀: 0.27 ± 0.121 nM and 1.32 ± 0.0956 nM, respectively) whereas p,p'-DDT and p,p'-DDE had weak ER agonistic activity with the maximal response of 28.70 ± 2.97% and 18.65 ± 1.77%, respectively. Concurrent treatment of the mycotoxins and/or pesticides, individually or in binary combination, with 17β-oestradiol (E₂) showed either additive, synergistic or antagonistic interactive effects on E₂-mediated ER response, depending on the combination ratios, the concentration range of xeno-oestrogens, and the concentration of E₂. This study highlights the importance of assessing the mixture effects of chemical contaminants in risk assessment, especially in the area of reproductive and developmental toxicity.

Cyclopiazonic acid decreases sperm quality and in vitro fertilisation rate in mice

The presence of cyclopiazonic acid (CPA) as a mycotoxin has been reported in feed and foodstuffs. The aim of this investigation was to determine the effects of CPA on reproductive functions of male mice. In this experiment, 40 mature male mice were randomly assigned into five groups (n=8): control, control-sham, CPA (0.03 mg/kg, body weight (BW)), CPA (0.06 mg/kg, BW) and CPA (0.12 mg/kg, BW). Following 28 days exposure to CPA, sperm quality parameters, in vitro fertilisation (IVF) capacity of sperms, serum testosterone level, Leydig cells number and serum total antioxidant capacity (TAC) were analysed. The results revealed a significant (P<0.05) reduction in sperm count, sperm viability, sperm motility, chromatin quality of sperm, sperms with intact DNA, IVF rate, testosterone level, Leydig cell distribution and TAC in comparison to the control group. The most prominent detrimental effects of CPA were found at the highest given dose level. Our results suggest that CPA at higher dose levels exerts detrimental effects on the male reproductive system. Moreover, these descriptive warrant further investigations into the specific mechanisms of action and the effects of CPA on spermatogenesis.

The effect of HT-2 toxin on ovarian steroidogenesis and its response to IGF-I, leptin and ghrelin in rabbits

T-2 toxin and its metabolite HT-2 toxin are one of the most toxic mycotoxins of type A-trichothecenes, which are produced mainly by Fusarium species. Therefore, study of Fusarium toxins T-2 toxin and HT-2 toxin is an essential issue because they could also play role in failures of reproductive functions as well as endocrine system of domestic animals. Assessment of the effect of A-trichothecene mycotoxin HT-2 toxin alone or combined with insulin-like growth factor (IGF-I), leptin and ghrelin on estradiol secretion by rabbit ovarian fragments in vitro was done. Rabbit ovarian fragments were incubated without (control group) or with HT-2 toxin, or its combinations with IGF-I, leptin and ghrelin at various concentrations for 24 h. Secretion of 17beta-estradiol was determined by ELISA. Firstly, HT-2 toxin at the doses 10 and 100 ng.ml(-1), but not at 1 ng.ml(-1) decreased 17beta-estradiol secretion by ovarian fragments. Secondly, 17beta-estradiol secretion was not affected by HT-2 toxin exposure combined with growth factor IGF-I, metabolic hormones leptin and ghrelin. In conclusion, HT-2 toxin has potent direct dose-dependent effects on ovarian steroidogenesis in rabbits. These direct effects of HT-2 mycotoxin on ovarian steroidogenesis could impact negatively on the reproductive performance of rabbits.

Effects of antihistamines on the H295R steroidogenesis - Autocrine up-regulation following 3β-HSD inhibition

Millions of people of all ages suffer from allergies worldwide and as a consequence antihistamines are among the most commonly prescribed pharmaceuticals in the world. We investigated the disruptive effects of three antihistamines, promethazine (PMZ), cetirizine (CET) and fexofenadine (FEX) on the H295R steroidogenesis. A multi-steroid LC-MS/MS method was used to quantify 13 steroid hormones in the steroidogenesis. In addition, real-time RT-PCR was used to determine if exposure to antihistamines altered gene expression in the cell line. When exposing the H295R cells to PMZ and CET, significant increases in Δ⁵-steroids and significant decreases in Δ⁴-steroids were observed, indicating an inhibition of 3β-hydroxysteroid dehydrogenase (3β-HSD). A sequential decrease in corticosteroids, androgens and estrogens were also observed. Overall, FEX had no effect on the steroidogenesis even though minor effects were observed at the highest concentrations. Real-time RT-PCR showed that PMZ resulted in significant up-regulation of 3β-HSD and 17β-HSD, whereas CET only resulted in up-regulation of 3β-HSD. This indicated that the decrease in steroids downstream from 3β-HSD following PMZ and CT exposure induced a compensatory autocrine response in 3β-HSD gene expression. The effects on the steroidogenesis were observed at concentrations 30-50 times higher than the therapeutic plasma concentrations. However, antihistamines are lipophilic and may accumulate in adrenals and gonads. Thus, disruptive effects of PMZ and CET on human steroidogenesis cannot be excluded.

The influence of deoxynivalenol and zearalenone on steroid hormone production by porcine ovarian granulosa cells in vitro

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) are frequently occurring in feed of pigs together. The aim of this study was to evaluate the possible in vitro effects of DON and ZEA, alone or their combination on steroid secretion of porcine ovarian granulosa cells (GCs). A species-specific model with porcine ovarian GCs was used to study the potential endocrine disrupting effects of DON and ZEA alone and in co-exposure. Progesterone (P4) and estradiol (E2) were determined by radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA). The results of this study demonstrate that DON alone at the higher concentrations may act to stimulate P4 (at 1,000, 2,000, 3,000 and 5,000 ng mL^-1 but not 10 and 100 ng mL^-1) and E2 (at 2,000, 3,000 and 5,000 ng mL^-1 but not 10, 100 and 1000 ng mL^-1) secretion. The effects of ZEA on P4 and E2 secretion were not confirmed. DON in combination with the other fusariotoxin ZEA may impair steroidogenesis. Results aslo demonstrate different toxicological effects of fusariotoxins on follicle stimulating hormone-induced secretion of P4 and E2. All these results taken together suggest that fusariotoxin and their interactions can impact ovarian steroidogenesis, thereby demonstrating their potential reproductive effects in pigs.

Engaging One Health for Non-Communicable Diseases in Africa: Perspective for Mycotoxins

The role of mycotoxins-e.g., aflatoxins, ochratoxins, trichothecenes, zearalenone, fumonisins, tremorgenic toxins, and ergot alkaloids-has been recognized in the etiology of a number of diseases. In many African countries, the public health impact of chronic (indoor) and/or repeated (dietary) mycotoxin exposure is largely ignored hitherto, with impact on human health, food security, and export of African agricultural food products. Notwithstanding, African scientific research reached milestones that, when linked to findings gained by the international scientific community, make the design and implementation of science-driven governance schemes feasible. Starting from Nigeria as leading African Country, this article (i) overviews available data on mycotoxins exposure in Africa; (ii) discusses new food safety issues, such as the environment-feed-food chain and toxic exposures of food producing animals in risk assessment and management; (iii) identifies milestones for mycotoxins risk management already reached in West Africa; and (iv) points out preliminary operationalization aspects for shielding communities from direct (on health) and indirect (on trade, economies, and livelihoods) effects of mycotoxins. An African science-driven engaging of scientific knowledge by development actors is expected therefore. In particular, One health/One prevention is suggested, as it proved to be a strategic and sustainable development framework.

Mycotoxin binders potential on histological of ovary mice exposed by zearalenone

Aim:

This study was conducted to examine the potential of mycotoxin binder in ceasing zearalenone (ZEN) effect on mice reproduction. ZEN mycotoxin can induce reactive oxygen species that may cause damage and cell death. ZEN is estrogenic so that it may affect the reproductive organs failure.

Materials and Methods:

Mycotoxin binder administration to female mice exposed to ZEN was aimed to count the number of primary follicles, secondary follicles, tertiary follicles, de Graaf’s follicles, and the corpus luteum (CL). Negative control group (C) was not exposed to ZEN and without the administration of mycotoxin binders, while positive control group (C+) was exposed to 0.1 mg/mouse/day ZEN and without the provision of mycotoxin binders. Treatment groups (T1, T2, T3) were exposed to 0.1 mg/mouse/day ZEN and mycotoxin binders 0.5; 1; 2 mg/BW/day.

Results:

ZEN and mycotoxin binders administration was conducted for 10 days. The number of primary follicles, secondary, tertiary, de Graaf’s follicles and CL in negative control (C−) was 14.2±1.36, 11.2±0.28, 6.5±0.53, 7.5±0.74, and 2.3±0.35. The number in positive control (C+) group was as follows 7.1±0.12, 3.7±1.17, 3.8±1.21, 1.5±0.62, and 2.3±0.34. Results in treatment 1 (T1) were as follows 6.2±0.16, 5.2±0.16, 3.6±0.16, 2.6±0.19, and 2.6±0.10; in treatment 2 (T2) 7.8±0.28, 5.8±0.53, 3.7±0.26, 2.7±0.26, and 2.5±0.10; and in treatment 3 (T3) 8.4±0.34, 8.4±0.34, 4.6±0.34, 4.5±1.01, and 3.4±0.23.

Conclusion:

The number of follicles and CL more in line with increasing doses of mycotoxin binders. Required more than 2 mg/mouse/day mycotoxin binders to inhibit the effects of ZEN so that its can maintain the number of primary follicle, secondary follicle, tertiary follicle, the de Graaf’s follicle, and the number of CL in the ovary of ZEN-exposed female mice (Mus musculus).

Deoxynivalenol induces toxic effects in the ovaries of pigs: An ex vivo approach

Deoxynivalenol (DON) is a frequently found trichothecene mycotoxin that elicits toxic effects on humans and animals. In pigs, DON induces changes in digestive and immune systems. Effects on the reproductive system are scarce and mainly based in in vitro models. The aim of this study was to evaluate, using an ex vivo model, the effects of DON on the morphology of ovaries of pigs in all stages of follicular development. Six 5-month-old pigs were used for sampling the explants. Thirty-six explants were incubated for 48 hours in culture medium (n = 18) or medium containing 10 μM of DON (n = 18). After the incubation period, the explants were submitted to histologic and immunohistochemical (proliferating cell nuclear antigen [PCNA] expression) analysis. Histologic changes were scored, and a lesional score was established. Oocytes and follicular cells immunostained for PCNA were counted. Explants exposed to DON showed a significant increase in the lesional score (P = 0.0004) compared to control explants. The main histologic changes were degeneration of oocytes and granulosa cells, interstitial edema and pyknotic cells. DON induced a reduction in the number of normal follicles in all stages of follicular development: primordial (P = 0.005), primary (P = 0.04), and growing follicles (P = 0.04) compared to control group. Deoxynivalenol also induced a significant increase (P ≤ 0.05) in the number of pyknotic oocytes in all stages of follicular development; however, no significant change in PCNA expression in oocytes or follicular cells was observed. These results indicated that DON induces toxic effects on the ovaries, affecting follicular development and interfering with reproductive parameters on pigs. Also, the present data indicate that ovarian explants are an adequate model for assessing reproductive toxicity.

Endocrine activity of mycotoxins and mycotoxin mixtures

Reporter gene assays incorporating nuclear receptors (estrogen, androgen, thyroid β and PPARγ2) have been implemented to assess the endocrine activity of 13 mycotoxins and their mixtures. As expected, zearalenone and its metabolites α-zearalenol and β- zearalenol turned out to have the strongest estrogenic potency (EC50 8,7 10-10 ± 0,8; 3,1 10-11 ± 0,5 and 1,3 10-8 ± 0,3 M respectively). The metabolite of deoxynivalenol, 3-acetyl-deoxynivalenol also had estrogenic activity (EC50 3,8 10-7 ± 1,1 M). Furthermore, most of the mycotoxins (and their mixtures) showed anti-androgenic effects (15-acetyldeoxynivalenol, 3-acetyl-deoxynivalenol and α-zearalenol with potencies within one order of magnitude of that of the reference compound flutamide). In particular, deoxynivalenol and 15-acetyl-deoxynivalenol acted as antagonists for the PPARy2 receptor. When testing mixtures of mycotoxins on the same cell systems, we showed that most of the mixtures reacted as predicted by the concentration addition (CA) theory. Generally, the CA was within the 95% confidence interval of the observed ones, only minor deviations were detected. Although these reporter gene tests cannot be directly extrapolated in vivo, they can be the basis for further research. Especially the additive effects of ZEN and its metabolites are of importance and could have repercussions in vivo.

Prepubertal exposure to T-2 toxin advances pubertal onset and development in female rats via promoting the onset of hypothalamic–pituitary–gonadal axis function

T-2 toxin, a naturally produced Type A trichothecene mycotoxin, has been shown to damage the reproductive and developmental functions in livestocks. However, whether T-2 toxin can disturb the pubertal onset and development following prepubertal exposure remains unclear. To clarify this point, infantile female Sprague–Dawley rats were given a daily intragastric administration of vehicle or T-2 toxin at a dose of 375 μg/kg body weight for 5 consecutive days from postnatal day (PND) 15–19 (PND15–PND19). The days of vaginal opening, first diestrus, and first estrus in regular estrous cycle were advanced following T-2 toxin treatment, indicating prepubertal exposure to T-2 toxin induced the advancement of puberty onset. The relative weights of uterus and ovaries and the incidence of corpora lutea were all increased in T-2 toxin-treated rats; serum hormone levels of luteinizing hormone and estradiol and the messenger RNA expressions of gonadotropin-releasing hormone (GnRH) and GnRH receptor also displayed marked increases following exposure to T-2 toxin, all of which were well consistent with the manifestations of the advanced puberty onset. In conclusion, the present study reveals that prepubertal exposure to a high level of T-2 toxin promotes puberty onset in infantile female rats by advancing the initiation of hypothalamic–pituitary–gonadal axis function in female rats.

Multifaceted impact of trichothecene metabolites on plant-microbe interactions and human health

Fungi present in rhizosphere produce trichothecene metabolites which are small in size and amphipathic in nature and some of them may cross cell membranes passively. Hypocreaceae family of rhizosphere fungi produce trichothecene molecules, however it is not a mandatory characteristic of all genera. Some of these molecules are also reported as growth adjuvant, while others are reported as deleterious for the plant growth. In this review, we are exploring the roles of these compounds during plant-microbe interactions. The three-way interaction among the plants, symbiotic microbial agents (fungi and bacteria), and the pathogenic microbes (bacteria, fungi) or multicellular pathogens like nematodes involving these compounds may only help us to understand better the complex processes happening in the microcosm of rhizosphere. These metabolites may further modulate the activity of different proteins involved in the cell signalling events of defence-related response in plants. That may induce the defence system against pathogens and growth promoting gene expression in plants, while in animal cells, these molecules have reported biochemical and pharmacological effects such as inducing oxidative stress, cell-cycle arrest and apoptosis, and may be involved in maintenance of membrane integrity. The biochemistry, chemical structures and specific functional group-mediated activity of these compounds have not been studied in details yet. Few of these molecules are also recently reported as novel anti-cancer agent against human chondrosarcoma cells.

The mycotoxin definition reconsidered towards fungal cyclic depsipeptides

Currently, next to the major classes, cyclic depsipeptides beauvericin and enniatins are also positioned as mycotoxins. However, as there are hundreds more fungal cyclic depsipeptides already identified, should these not be considered as mycotoxins as well? The current status of the mycotoxin definition revealed a lack of consistency, leading to confusion about what compounds should be called mycotoxins. Because this is of pivotal importance in risk assessment prioritization, a clear and quantitatively expressed mycotoxin definition is proposed, based on data of widely accepted mycotoxins. Finally, this definition is applied to a set of fungal cyclic depsipeptides, revealing that some of these should indeed be considered as mycotoxins.

In vitro effects of deoxynivalenol and zearalenone major metabolites alone and combined, on cell proliferation, steroid production and gene expression in bovine small-follicle granulosa cells

The effects of deoxynivalenol (DON) and zearalenone (ZEA) on reproduction in ruminants are unclear. This study was performed to evaluate the impact of DON and ZEA hydroxylated metabolites, α-zearalenol (α-Zol) and β-zearalenone (β-Zol), on cell proliferation, steroidogenesis and gene expression using bovine granulosa cells (GC). Cell proliferation was negatively affected after exposure to β-Zol at 31 μM and after exposure to α-Zol (3.1 μM) alone and combined with DON (3.3 μM). DON and α-Zol decreased steroidogenesis, while β-Zol at high concentration had stimulatory effects. DON and β-Zol increased CYP19A1 mRNA abundance. CYP11A1 mRNA abundance was stimulated by DON, alone and combined with α-Zol and β-Zol, whereas was inhibited by β-Zol alone. Generally mycotoxins effects on cell proliferation, steroidogenesis and gene expression were influenced by the presence or absence of IGF1. In conclusion DON and ZEA metabolites may impair in vitro cell proliferation, steroid production and gene expression in cattle.

Delay of the onset of puberty in female rats by prepubertal exposure to T-2 toxin

Growing evidence has revealed the deleterious influence of environmental and food contaminants on puberty onset and development in both animals and children, provoking an increasing health concern. T-2 toxin, a naturally-produced Type A trichothecene mycotoxin which is frequently found in cereal grains and products intended for human and animal consumption, has been shown to impair the reproduction and development in animals. Nevertheless, whether this trichothecene mycotoxin can disturb the onset of puberty in females remains unclear. To clarify this point, infantile female rats were given a daily intragastric administration of vehicle or 187.5 μg/kg body weight of T-2 toxin for five consecutive days from postnatal day 15 to 19, and the effects on puberty onset were evaluated in the present study. The results revealed that the days of vaginal opening, first dioestrus, and first estrus in regular estrous cycle were delayed following prepubertal exposure to T-2 toxin. The relative weights of reproductive organs uterus, ovaries, and vagina, and the incidence of corpora lutea were all diminished in T-2 toxin-treated rats. Serum levels of gonadotropins luteinizing hormone, follicle-stimulating hormone, and estradiol were also reduced by T-2 toxin treatment. The mRNA expressions of hypothalamic gonadotropin-releasing hormone (GnRH) and pituitary GnRH receptor displayed significant reductions following exposure to T-2 toxin, which were consistent with the changes of serum gonadotropins, delayed reproductive organ development, and delayed vaginal opening. In conclusion, the present study reveals that prepubertal exposure to T-2 toxin delays the onset of puberty in immature female rats, probably by the mechanism of disturbance of hypothalamic-pituitary-gonadal (HPG) axis function. Considering the vulnerability of developmental children to food contaminants and the relative high level of dietary intake of T-2 toxin in children, we think the findings of the present study provide valuable information for the health risk assessment in children.

Assessment of T-2 toxin effect and its metabolite HT-2 toxin combined with insulin-like growth factor I, leptin and ghrelin on progesterone secretion by rabbit ovarian fragments

Assessment of A-trichothecene mycotoxins (T-2 and HT-2 toxins) effect combined with growth factor IGF-I, and the metabolic hormones leptin and ghrelin on progesterone secretion by rabbit ovarian fragments was studied. Rabbit ovarian fragments were incubated without (control group) or with T-2/HT-2 toxin, or their combinations with insulin-like growth factor I (IGF-I), leptin or ghrelin at various concentrations for 24 h. Secretion of progesterone was determined by ELISA. First, T-2 toxin and HT-2 toxins at all doses used (0.01, 0.1, 1, 10, and 100 ng mL(-1)) were not shown to be potential regulators of progesterone secretion in rabbit ovarian fragments. Second, T-2 toxin but not HT-2 toxin combined with IGF-I was shown to be potential regulator of progesterone secretion in rabbit ovarian fragments. T-2 toxin at all doses used (0.01; 0.1; 1; 10; and 100 ng mL(-1)) combined with IGF-I (at dose 100 ng mL(-1)) significantly (P < 0.05) decreased progesterone secretion by rabbit ovarian fragments. Third, T-2 toxin and HT-2 toxin at all doses used in the study (0.01, 0.1, 1, 10, and 100 ng mL(-1)) combined with leptin (at dose 1000 ng mL(-1)) were not shown to be potential regulators of progesterone secretion in rabbit ovarian fragments. Furthermore, T-2 toxin and HT-2 toxin at all doses used in the study (0.01, 0.1, 1, 10, and 100 ng mL(-1)) combined with ghrelin (500 ng mL(-1)) were not shown to be potential regulators of progesterone secretion in rabbit ovarian fragments. Results in this study showed that trichothecene as T-2 toxin combined with IGF-I but not HT-2 toxin was able to decrease progesterone secretion in rabbit ovarian fragments in vitro. Experimental results of T-2 and HT-2 toxins combined with leptin and ghrelin did not confirm ability to modulate progesterone secretion by ovarian fragments in rabbits.

Mycotoxins and other fungal metabolites in grain dust from Norwegian grain elevators and compound feed mills

Employees at grain elevators and compound feed mills are exposed to large amounts of grain dust during work, frequently leading to airway symptoms and asthma. Although the exposure to grain dust, microorganisms, β-1→3-glucans and endotoxins has been extensively studied, the focus on the mycotoxin content of grain dust has previously been limited to one or few mycotoxins. Our objective was therefore to screen settled grain dust from grain elevators and compound feed mills for fungal metabolites by LC/MS-MS and explore differences between work places, seasons and climatic zones. Seventy fungal metabolites and two bacterial metabolites were detected. Trichothecenes, depsipeptides, ergot alkaloids, and other metabolites from Fusarium, Claviceps, Alternaria, Penicillium, Aspergillus, and other fungi were represented. The prevalence of individual metabolites was highly variable, and the concentration of each metabolite varied considerably between samples. The prevalence and concentration of most metabolites were higher in grain elevators compared to compound feed mills. Differences between seasons and climatic zones were inconclusive. All samples contained multiple mycotoxins, indicating a highly complex pattern of possible inhalational exposure. A mean exposure of 20 ng/m3 of fungal metabolites was estimated, whereas a worst case scenario estimated as much as 10 ?g/m3. Although many of these compounds may be linked to toxicological and immunological effects through experimental or epidemiological studies, it still remains to be determined whether the detected concentrations implicate adverse health outcomes when inhaled.

T-2 toxin and its metabolite HT-2 toxin combined with insulin-like growth factor-I modify progesterone secretion by porcine ovarian granulosa cells

The aim of this study was to examine the effect of A-trichothecenes T-2 and HT-2 toxins combined with insulin-like growth factor I (IGF-I) on the release of steroid hormone progesterone (P4) by porcine ovarian granulosa cells (GCs). The cells were incubated without (control) or with treatments of A-trichothecenes T-2 (100 and 1000 ng/mL)/ HT-2 (100 and 1000 ng/mL) combined with IGF-I (1, 10 and 100 ng/mL) for 24 h. Progesterone secretion was determined by RIA. The release of P4 by GCs after addition of T-2 toxin (at 100 ng/mL) combined with IGF-I (at 10 but not at 1 and 100 ng/mL) and HT-2 toxin (at 100 ng/mL) combined with IGF-I (at all doses) was significantly (P < 0.05) inhibited. On the other hand the release of P4 after addition of T-2/ HT-2 toxin (at 1000 ng/mL) combined with IGF-I (at all doses) was significantly (P < 0.05) stimulated. Alone IGF-I addition (at 10, 100 but not at 1 ng/mL) significantly (P < 0.05) stimulated P4 release by GCs. The results of our in vitro study indicate the T-2 and HT-2 toxins combined with IGF-I could modify progesterone secretion by porcine ovarian granulosa cells and potentially regulate process of steroidogenesis in the ovaries. Currently, occurrence of mycotoxins in food and feed is a worldwide problem and therefore study of these toxins as well as their interaction with different substances such as growth factors could be beneficial for better understanding of mechanism of their toxic effects in organism.

Mycotoxins and female reproduction: in vitro approaches

Exposure to mycotoxins has been linked to adverse effects on female reproduction by interfering with the synthesis, metabolism or degradation of steroid hormones, interaction with steroid receptors or impairing oocyte maturation and competence. To assess such effects, many studies initially focussed on possible endocrine actions of mycotoxins using specific cell lines known to express key enzymes involved in the synthesis of steroid hormones. Using these models, zearalenone, deoxynivalenol, ochratoxin A, T-2 and HT-2 toxins, and aflatoxin B1 were claimed to be endocrine active substances. As yet, zearalenone is the only mycotoxin for which a direct interaction with oestrogen receptors could be demonstrated, classifying this mycotoxin as an endocrine disruptor. Mycotoxin exposure of complex cell systems like ovarian follicles at the earliest (primordial) to most advanced (pre-ovulatory) stages can serve not only as the first indication of the potential of a mycotoxin to affect female reproduction, but also provides insight in specific mechanisms involved in such an effect and identifies vulnerable phases in follicle development. Zearalenone is the most widely studied mycotoxin regarding female reproduction, but effects on oocyte maturation have also been demonstrated for deoxynivalenol. Exposure to zearalenone impairs the formation of primordial, while its metabolite ?-zearalenol is more harmful to fertilised oocytes than zearalenone itself. This short overview aims to provide an introduction into the different models, such as cell lines and oocytes, commonly used to assess the potential adverse effects of mycotoxins on female reproduction.

An in vitro investigation of endocrine disrupting effects of the mycotoxin alternariol

Alternariol (AOH) is a mycotoxin commonly produced by Alternaria alternata on a wide range of foods. Few studies to date have been performed to evaluate the effects of AOH on endocrine activity. The present study makes use of in vitro mammalian cellular based assays and gene expression to investigate the ability of AOH to act as an endocrine disruptor by various modes of action. Reporter gene assays (RGAs), incorporating natural steroid hormone receptors for oestrogens, androgens, progestagens and glucocorticoids were used to identify endocrine disruption at the level of nuclear receptor transcriptional activity, and the H295R steroidogenesis assay was used to assess endocrine disruption at the level of gene expression and steroid hormone production. AOH exhibited a weak oestrogenic response when tested in the oestrogen responsive RGA and binding of progesterone to the progestagen receptor was shown to be synergistically increased in the presence of AOH. H295R cells when exposed to 0.1-1000ng/ml AOH, did not cause a significant change in testosterone and cortisol hormones but exposure to 1000ng/ml (3.87μM) AOH resulted in a significant increase in estradiol and progesterone production. In the gene expression study following exposure to 1000ng/ml (3.87μM) AOH, only one gene NR0B1 was down-regulated, whereas expression of mRNA for CYP1A1, MC2R, HSD3B2, CYP17, CYP21, CYP11B2 and CYP19 was up-regulated. Expression of the other genes investigated did not change significantly. In conclusion AOH is a weak oestrogenic mycotoxin that also has the ability to interfere with the steroidogenesis pathway.

From the gut to the brain: journey and pathophysiological effects of the food-associated trichothecene mycotoxin deoxynivalenol

Mycotoxins are fungal secondary metabolites contaminating food and causing toxicity to animals and humans. Among the various mycotoxins found in crops used for food and feed production, the trichothecene toxin deoxynivalenol (DON or vomitoxin) is one of the most prevalent and hazardous. In addition to native toxins, food also contains a large amount of plant and fungal derivatives of DON, including acetyl-DON (3 and 15ADON), glucoside-DON (D3G), and potentially animal derivatives such as glucuronide metabolites (D3 and D15GA) present in animal tissues (e.g., blood, muscle and liver tissue). The present review summarizes previous and very recent experimental data collected in vivo and in vitro regarding the transport, detoxification/metabolism and physiological impact of DON and its derivatives on intestinal, immune, endocrine and neurologic functions during their journey from the gut to the brain.