Aflatoxin B1 metabolism: Regulation by phase I and II metabolizing enzymes and chemoprotective agents

Aflatoxins in cereal based products-an overview of occurrence, detection and health implication

Aflatoxins are naturally produced toxins by specific molds, namely Aspergillus flavus and Aspergillus parasiticus. These toxins can be found in various agricultural products, including crops like maize, peanuts, cottonseed, and tree nuts. They have the potential to contaminate the food supply during different stages of production, processing, and storage. Aflatoxin is a very poisonous substance that has been linked to adverse health effects in both humans and animals. It is essential to detect and monitor aflatoxins to ensure the safety of food. Efficient and precise analytical techniques, such as chromatography and immunoassays, have been used to accurately measure the levels of aflatoxins in different substances. Regulatory bodies and worldwide associations have determined maximum permissible limits for aflatoxins in food and nourishment products to protect the well-being of the general public. Effectively addressing aflatoxin contamination necessitates a comprehensive approach that encompasses various strategies in agriculture, post-harvest practices, and regulatory measures. Continuous research and collaborative endeavors are crucial in order to minimize aflatoxin exposure and mitigate the associated risks. This review offers a comprehensive examination of the presence, health consequences, and elimination techniques associated with aflatoxins.

Biological Mechanisms of Aflatoxin B1-Induced Bile Metabolism Abnormalities in Ducklings

This study investigated the effects and biological mechanisms of aflatoxin B1 (AFB1) on the health and bile metabolism of ducklings. Forty-eight 1-day-old ducklings were randomly assigned to two groups, with six replicates per group. The control group was fed a basic diet, while the AFB1 group received a diet containing 90 µg/kg of AFB1. The experiment lasted for 2 weeks. The results showed that 90 µg/kg AFB1 caused abnormal bile metabolism; damaged liver cell nuclei and mitochondria; and significantly decreased body weight, average daily weight gain, and levels of albumin, total protein, cholesterol, total superoxide dismutase, glutathione peroxidase, and glutathione. It also significantly increased feed conversion efficiency, along with alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total bile acids, and malondialdehyde levels. In the liver, the expression levels of CYP7A1, SCD, and other genes were significantly upregulated, while BSEP, FASN, HMGCR, CAT, and other genes were significantly downregulated. In conclusion, AFB1 causes abnormal bile metabolism and impairs the overall health and liver function of ducklings. Its mechanism of action may involve changes in gene expression related to bile acid metabolism, lipid metabolism, oxidative damage, and cancer pathways.

Removal of aflatoxin M1 in milk using magnetic laccase/MoS2/chitosan nanocomposite as an efficient sorbent

The current study tries to find the impact of the integration of laccase enzyme (Lac) onto magnetized chitosan (Cs) nanoparticles composed of molybdenum disulfide (MoS2 NPs) (Fe3O4/Cs/MoS2/Lac NPs) on the removal of AFM1 in milk samples. The Fe3O4/Cs/MoS2/Lac NPs were characterized by FT-IR, XRD, BET, TEM, FESEM, EDS, PSA, and VSM analysis. The cytotoxic activity of the synthesized nanoparticles in different concentrations was evaluated using the MTT method. The results show that the synthesized nanoparticles don't have cytotoxic activity at concentrations less than 20 mg/l. The ability of the prepared nanoparticles to remove AFM1 was compared by bare laccase enzyme, MoS2, and Fe3O4/Cs/MoS2 composite, indicating that the Fe3O4/Cs/MoS2/Lac NPs the highest adsorption efficiency toward AFM1. Besides, the immobilization efficiency of laccase with a concentration range of 0.5-2.0 was investigated, indicating that the highest activity recovery of 96.8% was obtained using 2 mg/ml laccase loading capacity. The highest removal percentage of AFM1 (68.5%) in the milk samples was obtained by the Fe3O4/Cs/MoS2/Lac NPs at a contact time of 1 h. As a result, Fe3O4/MoS2/Cs/Lac NPs can potentially be utilized as an effective sorbent with high capacity and selectivity to remove AFM1 from milk samples.

New insights into aflatoxin B1 mechanistic toxicology in cattle liver: an integrated approach using molecular docking and biological evaluation in CYP1A1 and CYP3A74 knockout BFH12 cell lines

Aflatoxin B1 (AFB1) is a pro-carcinogenic compound bioactivated in the liver by cytochromes P450 (CYPs). In mammals, CYP1A and CYP3A are responsible for AFB1 metabolism, with the formation of the genotoxic carcinogens AFB1-8,9-epoxide and AFM1, and the detoxified metabolite AFQ1. Due to climate change, AFB1 cereals contamination arose in Europe. Thus, cattle, as other farm animals fed with grains (pig, sheep and broiler), are more likely exposed to AFB1 via feed with consequent release of AFM1 in milk, posing a great concern to human health. However, knowledge about bovine CYPs involved in AFB1 metabolism is still scanty. Therefore, CYP1A1- and CYP3A74-mediated molecular mechanisms of AFB1 hepatotoxicity were here dissected. Molecular docking of AFB1 into CYP1A1 model suggested AFB1 8,9-endo- and 8,9-exo-epoxide, and AFM1 formation, while docking of AFB1 into CYP3A74 pointed to AFB1 8,9-exo-epoxide and AFQ1 synthesis. To biologically confirm these predictions, CYP1A1 and CYP3A74 knockout (KO) BFH12 cell lines were exposed to AFB1. LC-MS/MS investigations showed the abolished production of AFM1 in CYP1A1 KO cells and the strong increase of parent AFB1 in CYP3A74 KO cells; the latter result, coupled to a decreased cytotoxicity, suggested the major role of CYP3A74 in AFB1 8,9-exo-epoxide formation. Finally, RNA-sequencing analysis indirectly proved lower AFB1-induced cytotoxic effects in engineered cells versus naïve ones. Overall, this study broadens the knowledge on AFB1 metabolism and hepatotoxicity in cattle, and it provides the weight of evidence that CYP1A1 and CYP3A74 inhibition might be exploited to reduce AFM1 and AFBO synthesis, AFB1 toxicity, and AFM1 milk excretion.

Aflatoxin B1 induces ROS-dependent mitophagy by modulating the PINK1/Parkin pathway in HepG2 cells

Aflatoxin B1 (AFB1) is extremely harmful to both humans and animals. Mitophagy is a selective process of self-elimination and has an important role in controlling mitochondrial quality. The present study aimed to investigate the effect of reactive oxygen species (ROS) accumulation on AFB1-induced mitophagy in HepG2 cells to provide a new perspective from which to design novel therapeutic strategies to treat AFB1 poisoning. ROS release was induced in HepG2 cells with AFB1 (10 μmol/L). Cell autophagy activity, mitochondrial membrane potential (MMP), adenosine triphosphate (ATP) levels, Parkin translocation and both the transcription and expression of mitophagy-related proteins were measured when N-acetyl-L-cysteine (NAC) partially decreased the ROS level, while the knockdown of nuclear factor erythroid 2-related factor 2 (Nrf2) resulted in a large accumulation of ROS. The results reveal that NAC pretreatment ameliorated the decline in both the MMP and the ATP levels while also activating phosphoglycerate mutase 5 (PGAM5)-PTEN-induced kinase 1 (PINK1)/Parkin, while the Nrf2 knockdown group exhibited the opposite trend. These results suggest that AFB1-induced mitophagy in HepG2 cells depends on ROS, and proper ROS activates mitophagy to play a protective role.

Detoxification of Aflatoxin B1 by Phytochemicals in Agriculture and Food Science

Aflatoxin B1 (AFB1), the most toxic and harmful mycotoxin, has a high likelihood of occurring in animal feed and human food, which seriously affects agriculture and food safety and endangers animal and human health. Recently, natural plant products have attracted widespread attention due to their low toxicity, high biocompatibility, and simple composition, indicating significant potential for resisting AFB1. The mechanisms by which these phytochemicals resist toxins mainly involve antioxidative, anti-inflammatory, and antiapoptotic pathways. Moreover, these substances also inhibit the genotoxicity of AFB1 by directly influencing its metabolism in vivo, which contributes to its elimination. Here, we review various phytochemicals that resist AFB1 and their anti-AFB1 mechanisms in different animals, as well as the common characteristics of phytochemicals with anti-AFB1 function. Additionally, the shortcomings of current research and future research directions will be discussed. Overall, this comprehensive summary contributes to the better application of phytochemicals in agriculture and food safety.

AP-1 and SP1 trans-activate the expression of hepatic CYP1A1 and CYP2A6 in the bioactivation of AFB1 in chicken

Dietary exposure to aflatoxin B1 (AFB1) is harmful to the health and performance of domestic animals. The hepatic cytochrome P450s (CYPs), CYP1A1 and CYP2A6, are the primary enzymes responsible for the bioactivation of AFB1 to the highly toxic exo-AFB1-8,9-epoxide (AFBO) in chicks. However, the transcriptional regulation mechanism of these CYP genes in the liver of chicks in AFB1 metabolism remains unknown. Dual-luciferase reporter assay, bioinformatics and site-directed mutation results indicated that specificity protein 1 (SP1) and activator protein-1 (AP-1) motifs were located in the core region -1,063/-948, -606/-541 of the CYP1A1 promoter as well as -636/-595, -503/-462, -147/-1 of the CYP2A6 promoter. Furthermore, overexpression and decoy oligodeoxynucleotide technologies demonstrated that SP1 and AP-1 were pivotal transcriptional activators regulating the promoter activity of CYP1A1 and CYP2A6. Moreover, bioactivation of AFB1 to AFBO could be increased by upregulation of CYP1A1 and CYP2A6 expression, which was trans-activated owing to the upregulalion of AP-1, rather than SP1, stimulated by AFB1-induced reactive oxygen species. Additionally, nano-selenium could reduce ROS, downregulate AP-1 expression and then decrease the expression of CYP1A1 and CYP2A6, thus alleviating the toxicity of AFB1. In conclusion, AP-1 and SP1 played important roles in the transactivation of CYP1A1 and CYP2A6 expression and further bioactivated AFB1 to AFBO in chicken liver, which could provide novel targets for the remediation of aflatoxicosis in chicks.

Involvement of aryl hydrocarbon receptor in the aflatoxin B1 and fumonisin B1 effects on in vitro differentiation of murine regulatory-T and Th17 cells

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely found as cereal contaminants, and their co-consumption is associated with liver cancer. Both are immunotoxic, but their interactions have been little studied. This work was aimed to evaluate in mouse spleen mononuclear cells (SMC) the effects of the exposure to AFB1 (5-50 µM), FB1 (25-250 µM), and AFB1-FB1 mixtures (MIX) on the in vitro differentiation of regulatory T cells (Treg and Tr1-like) and Th17 cells, as well as elucidate the contribution of aryl hydrocarbon receptor (Ahr) in such effects. AFB1 and mainly MIX induced cytotoxicity in activated CD4 cells via Ahr signaling. AFB1 (5 µM) increased the Treg cell differentiation, but its combination with FB1 (25 µM) also reduced Th17 cell expansion by Ahr-dependent mechanisms. Therefore, this mixture could enhance the Treg/Th17 cell ratio and favor immunosuppression and escape from tumor immunosurveillance to a greater extent than individual mycotoxins. Whereas, AFB1-FB1 mixtures at medium-high doses inhibited the Tr1-like cell expansion induced by the individual mycotoxins and affected Treg and Th17 cell differentiation in Ahr-independent and dependent manners, respectively, which could alter anti-inflammatory and Th17 immune responses. Moreover, individual FB1 altered regulatory T and Th17 cell development independently of Ahr. In conclusion, AFB1 and FB1 interact by modifying Ahr signaling, which is involved in the immunotoxicity as well as in the alteration of the differentiation of Treg, Tr1-like, and Th17 cells induced by AFB1-FB1 mixtures. Therefore, Ahr is implicated in the regulation of the anti- and pro-inflammatory responses caused by the combination of AFB1 and FB1.

Comprehensive Review of Aflatoxin and Ochratoxin A Dynamics: Emergence, Toxicological Impact, and Advanced Control Strategies

Filamentous fungi exhibit remarkable adaptability to diverse substrates and can synthesize a plethora of secondary metabolites. These metabolites, produced in response to environmental stimuli, not only confer selective advantages but also encompass potentially deleterious mycotoxins. Mycotoxins, exemplified by those originating from Alternaria, Aspergillus, Penicillium, and Fusarium species, represent challenging hazards to both human and animal health, thus warranting stringent regulatory control. Despite regulatory frameworks, mycotoxin contamination remains a pressing global challenge, particularly within cereal-based matrices and their derived by-products, integral components of animal diets. Strategies aimed at mitigating mycotoxin contamination encompass multifaceted approaches, including biological control modalities, detoxification procedures, and innovative interventions like essential oils. However, hurdles persist, underscoring the imperative for innovative interventions. This review elucidated the prevalence, health ramifications, regulatory paradigms, and evolving preventive strategies about two prominent mycotoxins, aflatoxins and ochratoxin A. Furthermore, it explored the emergence of new fungal species, and biocontrol methods using lactic acid bacteria and essential mustard oil, emphasizing their efficacy in mitigating fungal spoilage and mycotoxin production. Through an integrative examination of these facets, this review endeavored to furnish a comprehensive understanding of the multifaceted challenges posed by mycotoxin contamination and the emergent strategies poised to ameliorate its impact on food and feed safety.

Omics analysis revealed the intestinal toxicity induced by aflatoxin B1 and aflatoxin M1

Aflatoxin B1 (AFB1), a common mycotoxin, can occur in agricultural products. As a metabolite of AFB1, aflatoxin M1 (AFM1) mainly exist in dairy products. These two mycotoxins threaten human health, although it is unclear how they affect the function of the intestinal barrier. In this study, mice were exposed to AFB1 (0.3 mg/kg body b.w.) and AFM1(3.0 mg/kg b.w.) either individually or in combination for 28 days to explore the main differentially expressed proteins (DEPs) and the associated enriched pathways. These findings were preliminarily verified by the transcriptomic and proteomic analyses in differentiated Caco-2 cells. The results revealed that AFB1 and AFM1 exposure in mice disrupted the function of the intestinal barrier, and the combined toxicity was greater than that of each toxin alone. Further proteomic analysis in mice demonstrated that the mechanisms underlying these differences could be explained as follows: (i) lipid metabolism was enriched by AFB1-induced DEPs. (ii) protein export pathway was stimulated by AFM1-induced DEPs. (iii) cell metabolic ability was inhibited (as evidenced by changes in UDP-GT1, UDP-GT2, and Gatm6), apoptosis was induced (MAP4K3), and epithelial cell integrity was disrupted (Claudin7 and IQGAP2), resulting in more extensive intestinal damage after combined treatment. In conclusion, the hazardous impact of co-exposure to AFB1 and AFM1 from proteomic perspectives was demonstrated in the present study.

Aflatoxin B1-exposed hepatocyte-derived extracellular vesicles: Initiating hepatic stellate cell-mediated liver fibrosis through a p53-Parkin-dependent mitophagy pathway

Environmental aflatoxin B1 (AFB1) exposure has been proposed to contribute to hepatocellular carcinoma by promoting liver fibrosis, but the potential mechanisms remain to be further elucidated. Extracellular vesicles (EVs) were recognized as crucial traffickers for hepatic intercellular communication and play a vital role in the pathological process of liver fibrosis. The AFB1-exposed hepatocyte-derived EVs (AFB1-EVs) were extracted, and the functional effects of AFB1-EVs on the activation of hepatic stellate cells (HSCs) were explored to investigate the molecular mechanism of AFB1 exposure-induced liver fibrogenesis. Our results revealed that an environment-level AFB1 exposure induced liver fibrosis via HSCs activation in mice, while the AFB1-EVs mediated hepatotoxicity and liver fibrogenesis in vitro and in vivo. AFB1 exposure in vitro increased PINK1/Parkin-dependent mitophagy in hepatocytes, where upregulated transcription of the PARK2 gene via p53 nuclear translocation and mitochondrial recruitment of Parkin, and promoted AFB1-EVs-mediated mitochondria-trafficking communication between hepatocytes and HSCs. The knockdown of Parkin in HepaRG cells reversed HSCs activation by blocking the mitophagy-related AFB1-EVs trafficking. This study further revealed that the hepatic fibrogenesis of AFB1 exposure was rescued by genetic intervention with siPARK2 or p53's Pifithrin-α (PFTα) inhibitors. Furthermore, AFB1-EVs-induced HSCs activation was relieved by GW4869 pharmaceutic inhibition of EVs secretion. These results revealed a novel mechanism that AFB1 exposure-induced p53-Parkin signal axis regulated mitophagy-dependent hepatocyte-derived EVs to mediate the mitochondria-trafficking intercellular communication between hepatocytes and HSCs in the local hepatotoxic microenvironment to promote the activated HSCs-associated liver fibrogenesis. Our study provided insight into p53-Parkin-dependent pathway regulation and promised an advanced strategy targeting intervention to EVs-mediated mitochondria trafficking for preventing xenobiotics-induced liver fibrosis.

AFB1 Toxicity in Human Food and Animal Feed Consumption: A Review of Experimental Treatments and Preventive Measures

AIMS

The current review aims to outline and summarize the latest research on aflatoxin, with research studies describing natural, herbal and chemical compound applications in animal (pig) models and in vitro cellular studies. Aflatoxin, a carcinogenic toxin metabolite, is produced by Aspergillus flavus in humid environments, posing a threat to human health and crop production. The current treatment involves the prevention of exposure to aflatoxin and counteracting its harmful toxic effects, enabling survival and research studies on an antidote for aflatoxin.

OBJECTIVES

To summarize current research prospects and to outline the influence of aflatoxin on animal forage in farm production, food and crop processing. The research application of remedies to treat aflatoxin is undergoing development to pinpoint biochemical pathways responsible for aflatoxin effects transmission and actions of treatment.

SIGNIFICANCE

To underline the environmental stress of aflatoxin on meat and dairy products; to describe clinical syndromes associated with aflatoxicosis on human health that are counteracted with proposed treatment and preventive interventions. To understand how to improve the health of farm animals with feed conditions.

Integrated network toxicology, molecular docking, and in vivo experiments to elucidate molecular mechanism of aflatoxin B1 hepatotoxicity

Due to the rise in temperature and sea level caused by climate change, the detection rate of aflatoxin B1 (AFB1) in food crops has increased dramatically, and the frequency and severity of aflatoxicosis in humans and animals are also increasing. AFB1 has strong hepatotoxicity, causing severe liver damage and even cancer. However, the mechanism of AFB1 hepatotoxicity remains unclear. By integrating network toxicology, molecular docking and in vivo experiments, this research was designed to explore the potential hepatotoxicity mechanisms of AFB1. Thirty-three intersection targets for AFB1-induced liver damage were identified using online databases. PI3K/AKT1, MAPK, FOXO1 signaling pathways, and apoptosis were significantly enriched. In addition, the proteins of ALB, AKT1, PIK3CG, MAPK8, HSP90AA1, PPARA, MAPK1, EGFR, FOXO1, and IGF1 exhibited good affinity with AFB1. In vivo experiments, significant pathological changes occurred in the liver of mice. AFB1 induction increased the expression levels of EGFR, ERK, and FOXO1, and decreased the expression levsls of PI3K and AKT1. Moreover, AFB1 treatment caused an increase in Caspase3 expression, and a decrease in Bcl2/Bax ratio. By combining network toxicology with in vivo experiments, this study confirms for the first time that AFB1 promotes the FOXO1 signaling pathway by inactivating PI3K/AKT1 and activating EGFR/ERK signaling pathways, hence aggravating hepatocyte apoptosis. This research provides new strategies for studying the toxicity of environmental pollutants and new possible targets for the development of hepatoprotective drugs.

Human CYP1A1-activated aneugenicity of aflatoxin B1 in mammalian cells and its combined effect with benzo(a)pyrene

Aflatoxin B1 (AFB1) is the most toxic mycotoxin and a proven human carcinogen that requires metabolic activation, known by cytochrome P450 (CYP) 1A2 and 3A4. Previous evidence showed that AFB1 is activated by human recombinant CYP1A1 expressed in budding yeast. Yet, the toxicity, in particular the genotoxicity of the reactive metabolites formed from AFB1 remains unclear. Humans could be exposed to both AFB1 and benzo(a)pyrene (BaP) simultaneously, thus we were interested in their combined genotoxic effects subsequent to metabolic activation by CYP1A1. In this study, molecular docking of AFB1 to human CYP1A1 indicated that AFB1 is valid as a substrate. In the incubations with AFB1 in human CYP1A1-expressed microsomes, AFM1 as a marking metabolite of AFB1 was detected. Moreover, AFB1 induced micronucleus formation in a Chinese hamster V79-derived cell line and in a human lung epithelial BEAS-2B cell line, both expressing recombinant human CYP1A1, V79-hCYP1A1 and 2B-hCYP1A1 cells, respectively. Immunofluorescence of centromere protein B stained micronuclei was dominant in AFB1-treated BEAS-2B cells exposed to AFB1, suggesting an aneugenic effect. Moreover, AFB1 elevated the levels of ROS, 8-OHdG, AFB1-DNA adduct, and DNA breaks in 2B-hCYP1A1 cells, compared with those in the parental BEAS-2B cells. Meanwhile, AFB1 increased CYP1A1, RAD51, and γ-H2AX protein levels in 2B-hCYP1A1 cells, which were attenuated by the CYP1A1 inhibitor bergamottin. Co-exposure of AFB1 with BaP increased 8-OHdG, RAD51, and γ-H2AX levels (indicating DNA damage). In conclusion, AFB1 could be activated by human CYP1A1 for potent aneugenicity, which may be further enhanced by co-exposure to BaP.

Allocholic acid protects against α-naphthylisothiocyanate-induced cholestasis in mice by ameliorating disordered bile acid homeostasis

Cholestasis is a pathological condition characterized by disruptions in bile flow, leading to the accumulation of bile acids (BAs) in hepatocytes. Allocholic acid (ACA), a unique fetal BA known for its potent choleretic effects, reappears during liver regeneration and carcinogenesis. In this research, we investigated the protective effects and underlying mechanisms of ACA against mice with cholestasis brought on by α-naphthylisothiocyanate (ANIT). To achieve this, we combined network pharmacology, targeted BA metabolomics, and molecular biology approaches. The results demonstrated that ACA treatment effectively reduced levels of serum AST, ALP, and DBIL, and ameliorated the pathological injury caused by cholestasis. Network pharmacology analysis suggested that ACA primarily regulated BA and salt transport, along with the signaling pathway associated with bile secretion, to improve cholestasis. Subsequently, we examined changes in BA metabolism using UPLC-MS/MS. The findings indicated that ACA pretreatment induced alterations in the size, distribution, and composition of the liver BA pool. Specifically, it reduced the excessive accumulation of BAs, especially cholic acid (CA), taurocholic acid (TCA), and β-muricholic acid (β-MCA), facilitating the restoration of BA homeostasis. Furthermore, ACA pretreatment significantly downregulated the expression of hepatic BA synthase Cyp8b1, while enhancing the expression of hepatic efflux transporter Mrp4, as well as the renal efflux transporters Mdr1 and Mrp2. These changes collectively contributed to improved BA efflux from the liver and enhanced renal elimination of BAs. In conclusion, ACA demonstrated its potential to ameliorate ANIT-induced liver damage by inhibiting BA synthesis and promoting both BA efflux and renal elimination pathways, thus, restoring BA homeostasis.

Therapeutic detoxification of quercetin for aflatoxin B1-related toxicity: Roles of oxidative stress, inflammation, and metabolic enzymes

Aflatoxins (AFTs), a type of mycotoxin mainly produced by Aspergillus parasiticus and Aspergillus flavus, could be detected in food, feed, Chinese herbal medicine, grain crops and poses a great threat to public health security. Among them, aflatoxin B1 (AFB1) is the most toxic one. Exposure to AFB1 poses various health risks to both humans and animals, including the development of chronic inflammatory diseases, cardiovascular diseases, neurodegenerative diseases, and cancer. The molecular mechanisms underlying these risks are intricate and dependent on specific contexts. This review primarily focuses on summarizing the protective effects of quercetin, a natural phenolic compound, in mitigating the toxic effects induced by AFB1 in both in vitro experiments and animal models. Additionally, the review explores the molecular mechanisms that underlie these protective effects. Quercetin has been demonstrated to not only have the direct inhibitory action on the production of AFTs from Aspergillus, both also possess potent ameliorative effects against AFB1-induced cytotoxicity, hepatotoxicity, and neurotoxicity. These effects are attributed to the inhibition of oxidative stress, mitochondrial dysfunction, mitochondrial apoptotic pathway, and inflammatory response. It could also directly target several metabolic enzymes (i.e., CYP3As and GSTA1) to reduce the production of toxic metabolites of AFB1 within cells, then reduce AFB1-induced cytotoxicity. In conclusion, this review highlights quercetin is a promising detoxification agent for AFB1. By advancing our understanding of the protective mechanisms offered by quercetin, we aim to contribute to the development of effective detoxification agents against AFB1, ultimately promoting better health outcomes.

Chicken CYP1A5 is able to hydroxylate aflatoxin B1 to aflatoxin M1

Aflatoxin B1 (AFB1), a naturally-occurring mycotoxin, can cause severe toxicological and carcinogenic effects in livestock and humans. Given that the chicken is one of the most important food-producing animals, knowledge regarding AFB1 metabolism and enzymes responsible for AFB1 transformation in the chicken has important implications for chicken production and food safety. Previously, we have successfully expressed chicken CYP1A5 and CYP3A37 monooxygenases in E. coli, and reconstituted them into a functional CYP system consisting of CYP1A5 or CYP3A37, CPR and cytochrome b5. In this study, we aimed to investigate the roles of CYP1A5 and CYP3A37 in the bioconversion of AFB1 to AFM1. Our results showed that chicken CYP1A5 was able to hydroxylate AFB1 to AFM1. The formation of AFM1 followed the typical Michaelis-Menten kinetics. The kinetics parameters of Vmax and Km were determined as 0.83 ± 0.039 nmol/min/nmol P450 and 26.9 ± 4.52 μM respectively. Docking simulations further revealed that AFB1 adopts a "side-on" conformation in chicken CYP1A5, facilitating the hydroxylation of the C9a atom and the production of AFM1. On the other hand, AFB1 assumes a "face-on" conformation in chicken CYP3A37, leading to the displacement of the C9a atom from the heme iron and explaining the lack of AFM1 hydroxylation activity. The results demonstrate that chicken CYP1A5 possesses efficient hydroxylase activity towards AFB1 to form AFM1.

Biomonitoring of Dietary Mycotoxin Exposure and Associated Impact on the Gut Microbiome in Nigerian Infants

Mycotoxins are toxic chemicals that adversely affect human health. Here, we assessed the influence of mycotoxin exposure on the longitudinal development of early life intestinal microbiota of Nigerian neonates and infants (NIs). Human biomonitoring assays based on liquid chromatography tandem mass spectrometry were applied to quantify mycotoxins in breast milk (n = 68) consumed by the NIs, their stool (n = 82), and urine samples (n = 15), which were collected longitudinally from month 1-18 postdelivery. Microbial community composition was characterized by 16S rRNA gene amplicon sequencing of stool samples and was correlated to mycotoxin exposure patterns. Fumonisin B1 (FB1), FB2, and alternariol monomethyl ether (AME) were frequently quantified in stool samples between months 6 and 18. Aflatoxin M1 (AFM1), AME, and citrinin were quantified in breast milk samples at low concentrations. AFM1, FB1, and ochratoxin A were quantified in urine samples at relatively high concentrations. Klebsiella and Escherichia/Shigella were dominant in very early life stool samples (month 1), whereas Bifidobacterium was dominant between months 3 and 6. The total mycotoxin levels in stool were significantly associated with NIs' gut microbiome composition (PERMANOVA, p < 0.05). However, no significant correlation was observed between specific microbiota and the detection of certain mycotoxins. Albeit a small cohort, this study demonstrates that mycotoxins may influence early life gut microbiome composition.

Unravelling drug-drug interactions in pigs: Induction of hepatic cytochrome P450 1A (CYP1A) metabolism after the in-feed medication with the anthelmintic fenbendazole

The anthelmintic fenbendazole (FBZ) undergoes hepatic S‑oxygenation by monooxygenases belonging to the cytochrome P450 (CYP) and flavin-monooxygenase (FMO) families. The in-feed medication with FBZ induced CYP1A-dependent metabolism in pig liver. This fact may alter the metabolism of the anthelmintic itself, and of CYP1A substrates like aflatoxin B1 (AFB1). This work evaluated the effect of the in-feed administration of FBZ on CYP1A-dependent metabolism, on its own pattern of hepatic S‑oxygenation, and on the metabolism of AFB1. Landrace piglets remained untreated (n = 5) or received a pre-mix of FBZ (n = 6) in feed for 9 days. Pigs were slaughtered for preparation of liver microsomes used for: CYP content determination; monitoring the CYP1A-dependent enzyme activities, 7-ethoxyresorufin O-deethylase (EROD) and 7-methoxyresorufin O-demethylase (MROD); measurement of FBZ (50 μM) S‑oxygenation, and AFB1 (16 nM) disappearance from the incubation medium. In microsomes of FBZ-treated animals, EROD and MROD increased 19-fold (p = 0.002) and 14-fold (p = 0.003), respectively. An enhanced (3-fold, p = 0.004) participation of the CYP pathway in FBZ S‑oxygenation was observed in the liver of piglets treated with the anthelmintic (210 ± 69 pmol/min.nmol CYP) compared to untreated animals (68 ± 34 pmol/min.nmol CYP). AFB1 metabolism was 93% higher (p = 0.009) in the liver of FBZ-treated compared to untreated pigs. Positive and significant (p < 0.05) correlations were observed between CYP1A-dependent enzyme activities and FBZ or AFB1 metabolism. The sustained administration of FBZ caused an auto-induction of the CYP1A-dependent S‑oxygenation of this anthelmintic. The CYP1A induction triggered by the anthelmintic could amplify the production of AFB1 metabolites in pig liver, including the hepatotoxic AFB1-derived epoxide.+.

Key Role of Porcine Cytochrome P450 2A19 in the Bioactivation of Aflatoxin B1 in the Liver

The metabolic transformation of aflatoxin B1 (AFB1) in pigs remains understudied, presenting a gap in our toxicological understanding compared with extensive human-based research. Here, we found that the main products of AFB1 in porcine liver microsomes (PLMs) were AFB1-8,9-epoxide (AFBO), the generation of which correlated strongly with the protein levels and activities of cytochrome P450 (CYP)3A and CYP2A. In addition, we found that porcine CYP2A19 can transform AFB1 into AFBO, and its metabolic activity was stronger than the other CYPs we have reported, including CYP1A2, CYP3A29, and CYP3A46. Furthermore, we stably transfected all identified CYPs in HepLi cells and found that CYP2A19 stable transfected HepLi cells showed more sensitivity in AFB1-induced DNA adducts, DNA damage, and γH2AX formation than the other three stable cell lines. Moreover, the CYP2A19 N297A mutant that lost catalytic activity toward AFB1 totally eliminated AFB1-induced AFB1-DNA adducts and γH2AX formations in CYP2A19 stable transfected HepLi cells. These results indicate that CYP2A19 mainly mediated AFB1-induced cytotoxicity through metabolizing AFB1 into a highly reactive AFBO, promoting DNA adduct formation and DNA damage, and lastly leading to cell death. This study advances the current understanding of AFB1 bioactivation in pigs and provides a promising target to reduce porcine aflatoxicosis.

Screening the components in multi-biological samples and the comparative pharmacokinetic study in healthy and depression model rats of Suan-Zao-Ren decoction combined with a network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Suanzaoren Decoction (SZRD) is a classic traditional Chinese prescription, which has been commonly used for treating insomnia, depression and other nerve system diseases for a long time.

AIM OF THIS STUDY

The present study aimed to explore the metabolic profiles in multi-biological samples and pharmacokinetic mechanism between healthy and depression model rats combined with a network pharmacology approach after administration of SZRD.

MATERIALS AND METHODS

In our study, an ultra-high performance liquid chromatography (UPLC)-Q-Exactive Orbitrap Mass Spectrometry method was firstly used to study the prototype components and metabolites of SZRD in plasma, brain, urine, and feces between healthy and depressed rats. The possible metabolic pathways were also speculated. Then a network pharmacological study was conducted on the components in the plasma of model rats. According to the above components screened by network pharmacology and the other reported representative active components, the comparative pharmacokinetic study was established for the simultaneous determination of mangiferin, spinosin, ferulic acid, liquiritin, formononetin. magnoflorine and isoliquiritin between healthy and depression model rats. Finally, molecular docking was used to validate the binding affinity between key potential targets and active components in pharmacokinetics.

RESULTS

A total of 115 components were identified in healthy rats, and 101 components were identified in model rats. The prototype components and metabolites in plasma, brain, urine, and feces were also distinguished. The main metabolic pathways included phase I and phase II metabolic reactions, such as dehydrogenation, oxidation, hydroxylation, gluconaldehyde conjugation, glutathione conjugation and so on. These results provided a basis for the further study of antidepressive pharmacokinetic and pharmacological action in SZRD. Then, according to the degree value of network pharmacological study, it was predicted that 10 components and 10 core targets, which involved in the critical pathways such as neuroactive ligand-receptor interaction, cyclic adenosine monophosphate (cAMP) signaling pathway, serotonergic synapse, phosphatidylinositol-3 kinase (PI3K)-Akt signaling pathway, etc. Finally, the established pharmacokinetic method was successfully applied to compare the pharmacokinetic behavior of these 7 active components in plasma of healthy and depressed rats after oral administration of SZRD. It showed that except magnoflorine, the pharmacokinetic parameters of each component were different between healthy and depressed rats. Molecular docking analysis also indicated that the active compounds in pharmacokinetics could bind tightly to the key targets of network pharmacological study.

CONCLUSION

This study may provide important information for studying the action mechanism of SZRD in treating depression.

Hesperetin protects hippocampal neurons from the neurotoxicity of Aflatoxin B1 in mice

Aflatoxin B1 (AFB1) is a major food and feed pollutant that endangers public health. Previous studies have shown that exposure to AFB1 causes neurotoxicity in the body. However, the mechanism of neurotoxicity caused by AFB1 is not well understood, and finding a workable and practical method to safeguard animals from AFB1 toxicity is essential. This study confirmed that AFB1 caused endoplasmic reticulum stress (ER stress) and apoptosis in hippocampal neurons using C57BL/6 J mice and HT22 cells as models. In vitro experiments showed that the aryl hydrocarbon receptor (AHR) plays a significant role in the cytotoxicity of AFB1. Finally, we assessed how hesperetin protecting against the neurotoxicity caused by AFB1. Our findings demonstrated that AFB1 increased the levels of BAX and Cleaved-Caspase3 proteins, while decreasing the levels of BCL2 protein in the CA1 and CA3 regions of the hippocampus. The AFB1 increased the expression of AHR and activated nuclear translocation. It also elevated the expression levels of Chop, GRP78, p-IRE1/ Xbp1s, and p-PERK/p-EIF2a. Importantly, we also discovered for the first time that blocking AHR in HT22 cells dramatically reduced the level of ER stress and apoptosis caused by AFB1. In vivo and in vitro studies, supplementation of hesperetin effectively reversed AFB1-induced cytotoxicity. We have demonstrated that hesperetin effectively restored the imbalance in the GSH/GST system in HT22 cells treated with AFB1. Furthermore, we observed that elevated GSH levels facilitated the formation of AFB1-GSH complexes, which enhanced the excretion of AFB1. Therefore, hesperetin improves ER stress-induced apoptosis by reducing AFB1 activation of AHR.

Bile Acids Promote Hepatic Biotransformation and Excretion of Aflatoxin B1 in Broiler Chickens

Aflatoxin B1 (AFB1) is a hazardous mycotoxin that often contaminates animal feed and may potentially induce severe liver damage if ingested. The liver is the primary organ responsible for AFB1 detoxification through enzyme-catalyzed xenobiotic metabolism and bile acid (BA)-associated excretion. In this study, we sought to investigate whether exogenous BA improves hepatic AFB1 detoxification to alleviate AFB1-induced liver injury in broiler chickens. Five-day-old broiler chicks were randomly assigned to three groups. CON and AFB1 received a basal diet; AFB1 + BA received a basal diet with 250 mg/kg BA for 20 days. After a 3-day pre-feed, AFB1 and AFB1 + BA were daily gavaged with 250 μg/kg BW AFB1, while CON received gavage solvent for AFB1 treatment. Dietary BA supplementation protected chickens from AFB1-induced hepatic inflammation and oxidative stress. The hepatic biotransformation of AFB1 to its metabolite AFBO was improved, with accelerated excretion to the gallbladder and cecum. Accordantly, AFB1-induced down-regulation of detoxification genes, including cytochrome P450 enzymes, glutathione S-transferases, and the bile salt export pump, was rescued by BA supplementation. Moreover, liver X receptor α, suppressed by AFB1, was enhanced in BA-treated broiler chickens. These results indicate that dietary BA supplementation improves hepatic AFB1 detoxification and excretion through LXRα-involved regulation of xenobiotic enzymes.

Turmeric Powder Counteracts Oxidative Stress and Reduces AFB1 Content in the Liver of Broilers Exposed to the EU Maximum Levels of the Mycotoxin

The most frequent adverse effects of AFB1 in chicken are low performance, the depression of the immune system, and a reduced quality of both eggs and meat, leading to economic losses. Since oxidative stress plays a major role in AFB1 toxicity, natural products are increasingly being used as an alternative to mineral binders to tackle AFB1 toxicosis in farm animals. In this study, an in vivo trial was performed by exposing broilers for 10 days to AFB1 at dietary concentrations approaching the maximum limits set by the EU (0.02 mg/kg feed) in the presence or absence of turmeric powder (TP) (included in the feed at 400 mg/kg). The aims were to evaluate (i) the effects of AFB1 on lipid peroxidation, antioxidant parameters, histology, and the expression of drug transporters and biotransformation enzymes in the liver; (ii) the hepatic accumulation of AFB1 and its main metabolites (assessed using an in-house-validated HPLC-FLD method); (iii) the possible modulation of the above parameters elicited by TP. Broilers exposed to AFB1 alone displayed a significant increase in lipid peroxidation in the liver, which was completely reverted by the concomitant administration of TP. Although no changes in glutathione levels and antioxidant enzyme activities were detected in any treatment group, AFB1 significantly upregulated and downregulated the mRNA expression of CYP2A6 and Nrf2, respectively. TP counteracted such negative effects and increased the hepatic gene expression of selected antioxidant enzymes (i.e., CAT and SOD2) and drug transporters (i.e., ABCG2), which were further enhanced in combination with AFB1. Moreover, both AFB1 and TP increased the mRNA levels of ABCC2 and ABCG2 in the duodenum. The latter changes might be implicated in the decrease in hepatic AFB1 to undetectable levels ( Collapse

Key Words

• aflatoxin B1
• chicken
• curcumin
• drug transporters
• drug-metabolizing enzymes
• liver
• oxidative stress
• turmeric powder

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MESH Headings

• Animals
• Antioxidants/pharmacology
• Antioxidants/metabolism
• Chickens/metabolism
• Curcuma/metabolism
• Powders/metabolism
• Powders/pharmacology
• Mycotoxins/metabolism
• Aflatoxin B1/metabolism
• Liver
• Oxidative Stress
• RNA, Messenger/metabolism

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Grants

• 678781 European Union

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Affiliation(s)

Neenu Amminikutty Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Veronica Spalenza Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Watanya Jarriyawattanachaikul Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Paola Badino Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Maria Teresa Capucchio Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Elena Colombino Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Achille Schiavone Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Donato Greco Institute of Sciences of Food Production, Italian National Research Council, 70126 Bari, Italy; (D.G.); (V.D.); (G.A.)
Vito D’Ascanio Institute of Sciences of Food Production, Italian National Research Council, 70126 Bari, Italy; (D.G.); (V.D.); (G.A.)
Giuseppina Avantaggiato Institute of Sciences of Food Production, Italian National Research Council, 70126 Bari, Italy; (D.G.); (V.D.); (G.A.)
Sihem Dabbou Center Agriculture Food Environment (C3A), University of Trento, 38010 San Michele all’Adige, Italy;
Carlo Nebbia Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)
Flavia Girolami Department of Veterinary Sciences, University of Torino, 10095 Grugliasco, Italy; (N.A.); (V.S.); (W.J.); (P.B.); (M.T.C.); (E.C.); (A.S.); (F.G.)

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Comparative metabolism of aflatoxin B1 in mouse, rat and human primary hepatocytes using HPLC-MS/MS

Aflatoxin B1 (AFB1) is a highly hepatotoxic and carcinogenic mycotoxin produced by Aspergillus species. The compound is mainly metabolized in the liver and its metabolism varies between species. The present study quantified relevant AFB1- metabolites formed by mouse, rat, and human primary hepatocytes after treatment with 1 µM and 10 µM AFB1. The use of liquid chromatographic separation coupled with tandem mass spectrometric detection enabled the selective and sensitive determination of phase I and phase II metabolites of AFB1 over incubation times of up to 24 h. The binding of AFB1 to macromolecules was also considered. The fastest metabolism of AFB1 was observed in mouse hepatocytes which formed aflatoxin P1 as a major metabolite and also its glucuronidated form, while AFP1 occurred only in traces in the other species. Aflatoxin M1 was formed in all species and was, together with aflatoxin Q1 and aflatoxicol, the main metabolite in human cells. Effective epoxidation led to high amounts of DNA adducts already 30 min post-treatment, especially in rat hepatocytes. Lower levels of DNA adducts and fast DNA repair were found in mouse hepatocytes. Also, protein adducts arising from reactive intermediates were formed rapidly in all three species. Detoxification via glutathione conjugation and subsequent formation of the N-acetylcysteine derivative appeared to be similar in mice and in rats and strongly differed from human hepatocytes which did not form these metabolites at all. The use of qualitative reference material of a multitude of metabolites and the comparison of hepatocyte metabolism in three species using advanced methods enabled considerations on toxification and detoxification mechanisms of AFB1. In addition to glutathione conjugation, phase I metabolism is strongly involved in the detoxification of AFB1.

Aflatoxin B1-induced early developmental hepatotoxicity in larvae zebrafish

Aflatoxin B1 (AFB1) is a ubiquitous mycotoxin that causes oxidative damage in various organs. At present, the research studies on AFB1 are primarily focused on its effects on the terrestrial environment and animals. However, its toxicity mechanism in aquatic environments and aquatic animals has not been largely explored. Thus, in this study, zebrafish was used as a model to study the toxicity mechanism of AFB1 on the liver of developing larvae. The results showed that AFB1 exposure inhibited liver development and promoted fat accumulation in the liver. Transcriptome sequencing analysis showed that AFB1 affected liver redox metabolism and oxidoreductase activity. KEGG analysis showed that AFB1 inhibited the expression of gsto1, gpx4a, mgst3a, and idh1 in the glutathione metabolizing enzyme gene pathway, resulting in hepatic oxidative stress. At the same time, AFB1 also inhibited the expression of acox1, acsl1b, pparα, fabp2, and cpt1 genes in peroxidase and PPAR metabolic pathways, inducing hepatic steatosis and lipid droplet accumulation. Antioxidant N-Acetyl-l-cysteine (NAC) preconditioning up-regulated gsto1, gpx4a and idh1 genes, and improved the AFB1-induced lipid droplet accumulation in the liver. In summary, AFB1 induced hepatic oxidative stress and steatosis, resulting in abnormal liver fat metabolism and accumulation of cellular lipid droplets. NAC could be used as a potential preventative drug to improve AFB1-induced fat accumulation.

From cultivation to cancer: formation of N-nitrosamines and other carcinogens in smokeless tobacco and their mutagenic implications

Tobacco use is a major cause of preventable morbidity and mortality globally. Tobacco products, including smokeless tobacco (ST), generally contain tobacco-specific N-nitrosamines (TSNAs), such as N'-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-butanone (NNK), which are potent carcinogens that cause mutations in critical genes in human DNA. This review covers the series of biochemical and chemical transformations, related to TSNAs, leading from tobacco cultivation to cancer initiation. A key aim of this review is to provide a greater understanding of TSNAs: their precursors, the microbial and chemical mechanisms that contribute to their formation in ST, their mutagenicity leading to cancer due to ST use, and potential means of lowering TSNA levels in tobacco products. TSNAs are not present in harvested tobacco but can form due to nitrosating agents reacting with tobacco alkaloids present in tobacco during certain types of curing. TSNAs can also form during or following ST production when certain microorganisms perform nitrate metabolism, with dissimilatory nitrate reductases converting nitrate to nitrite that is then released into tobacco and reacts chemically with tobacco alkaloids. When ST usage occurs, TSNAs are absorbed and metabolized to reactive compounds that form DNA adducts leading to mutations in critical target genes, including the RAS oncogenes and the p53 tumor suppressor gene. DNA repair mechanisms remove most adducts induced by carcinogens, thus preventing many but not all mutations. Lastly, because TSNAs and other agents cause cancer, previously documented strategies for lowering their levels in ST products are discussed, including using tobacco with lower nornicotine levels, pasteurization and other means of eliminating microorganisms, omitting fermentation and fire-curing, refrigerating ST products, and including nitrite scavenging chemicals as ST ingredients.

Discovering the Protective Effects of Quercetin on Aflatoxin B1-Induced Toxicity in Bovine Foetal Hepatocyte-Derived Cells (BFH12)

Aflatoxin B1 (AFB1) induces lipid peroxidation and mortality in bovine foetal hepatocyte-derived cells (BFH12), with underlying transcriptional perturbations associated mainly with cancer, cellular damage, inflammation, bioactivation, and detoxification pathways. In this cell line, curcumin and resveratrol have proven to be effective in mitigating AFB1-induced toxicity. In this paper, we preliminarily assessed the potential anti-AFB1 activity of a natural polyphenol, quercetin (QUE), in BFH12 cells. To this end, we primarily measured QUE cytotoxicity using a WST-1 reagent. Then, we pre-treated the cells with QUE and exposed them to AFB1. The protective role of QUE was evaluated by measuring cytotoxicity, transcriptional changes (RNA-sequencing), lipid peroxidation (malondialdehyde production), and targeted post-transcriptional modifications (NQO1 and CYP3A enzymatic activity). The results demonstrated that QUE, like curcumin and resveratrol, reduced AFB1-induced cytotoxicity and lipid peroxidation and caused larger transcriptional variations than AFB1 alone. Most of the differentially expressed genes were involved in lipid homeostasis, inflammatory and immune processes, and carcinogenesis. As for enzymatic activities, QUE significantly reverted CYP3A variations induced by AFB1, but not those of NQO1. This study provides new knowledge about key molecular mechanisms involved in QUE-mediated protection against AFB1 toxicity and encourages in vivo studies to assess QUE's bioavailability and beneficial effects on aflatoxicosis.

Yeast polysaccharide mitigated oxidative injury in broilers induced by mixed mycotoxins via regulating intestinal mucosal oxidative stress and hepatic metabolic enzymes

This study was aimed to investigate the effects of yeast polysaccharides (YPS) on growth performance, intestinal health, and aflatoxin metabolism in livers of broilers fed diets naturally contaminated with mixed mycotoxins (MYCO). A total of 480 one-day-old Arbor Acre male broilers were randomly allocated into a 2 × 3 factorial arrangement of treatments (8 replicates with 10 birds per replicate) for 6 wk to assess the effects of 3 levels of YPS (0, 1, or 2 g/kg) on the broilers fed diets contaminated with or without MYCO (95 μg/kg aflatoxin B1, 1.5 mg/kg deoxynivalenol, and 490 μg/kg zearalenone). Results showed that mycotoxins contaminated diets led to significant increments in serum malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels, mRNA expressions of TLR4 and 4EBP1 associated with oxidative stress, mRNA expressions of CYP1A1, CYP1A2, CYP2A6, and CYP3A4 associated with hepatic phase Ⅰ metabolizing enzymes, mRNA expressions of p53 associated with hepatic mitochondrial apoptosis, and AFB1 residues in the liver (P < 0.05); meanwhile dietary MYCO decreased the jejunal villus height (VH), villus height/crypt depth (VH/CD), the activity of serum total antioxidant capacity (T-AOC), mRNA expressions of jejunal HIF-1α, HMOX, and XDH associated with oxidative stress, mRNA expressions of jejunal CLDN1, ZO1, and ZO2, and mRNA expression of GST associated with hepatic phase Ⅱ metabolizing enzymes of broilers (P < 0.05). Notably, the adverse effects induced by MYCO on broilers were mitigated by supplementation with YPS. Dietary YPS supplementation reduced the concentrations of serum MDA and 8-OHdG, jejunal CD, mRNA expression of jejunal TLR2, and 4EBP1, hepatic CYP1A2, and p53, and the AFB1 residues in the liver (P < 0.05), and elevated the serum T-AOC and SOD, jejunal VH, and VH/CD, and mRNA expression of jejunal XDH, hepatic GST of broilers (P < 0.05). There were significant interactions between MYCO and YPS levels on the growth performance (BW, ADFI, ADG, and F/G) at d 1 to 21, d 22 to 42, and d 1 to 42, serum GSH-Px activity, and mRNA expression of jejunal CLDN2 and hepatic ras of broilers (P < 0.05). In contrast with MYCO group, the addition of YPS increased BW, ADFI, and ADG, the serum GSH-Px activity (14.31%-46.92%), mRNA levels of jejunal CLDN2 (94.39%-103.02%), decreased F/G, and mRNA levels of hepatic ras (57.83%-63.62%) of broilers (P < 0.05). In conclusion, dietary supplements with YPS protected broilers from mixed mycotoxins toxicities meanwhile keeping normal performance of broilers, presumably via reducing intestinal oxidative stress, protecting intestinal structural integrity, and improving hepatic metabolic enzymes to minimize the AFB1 residue in the liver and enhance the performance of broilers.

Contribution of Aflatoxin B1 Exposure to Liver Cirrhosis in Eastern Ethiopia: A Case-Control Study

Background

Liver cirrhosis is a global health problem due to a large number of disability-associated life years and mortality. However, evidence is scarce on its causes in Eastern-Ethiopia, a place where there is a high prevalence of liver cirrhosis of unknown etiology. This study attempted to identify the risk factors related to liver cirrhosis in the area.

Methods

A case-control study was conducted at a tertiary care hospital from January 2020 to July 2021. Following diagnoses using an ultrasound-based cirrhosis scale, a total of 127 cases were identified and compared with 253 control patients. A structured questionnaire and data abstraction form were used to collect demographic, lifestyle, and clinical information. A blood sample was also taken from each participant for clinical chemistry, hepatitis B virus (HBV), and hepatitis C virus tests as well as for an aflatoxin B1 (AFB1) albumin adduct (AF-alb) assay. Binary logistic regression analysis was used to determine predictors of liver cirrhosis.

Results

AF-alb levels were detected in 75% of the cases and 64% of the controls, with a median (IQR) level of 11 pg/mg (5.5-25) and 7.0 pg/mg (4.3-20.5), respectively (p<0.05). Moreover, the number of subjects with high AF-alb levels (≥8.6 pg/mg) was greater in cases (45%, p<0.05)) than controls (28%). Age ≥55 years (adjusted odds ratio (AOR)=0.4; 95% CI: 0.2, 0.8), being a farmer (AOR= 3.0; 95% CI: 1.5, 6.0), family history of liver disease (AOR= 2.9; 95% CI: 1.1, 7.9), HBV seropositivity (AOR=4.0; 95% CI: 1.9, 8.8), and exposure to high levels of AF-alb (AOR=2.0; 95% CI: 1.1, 3.7) were significantly associated with liver cirrhosis.

Conclusion

This study found a strong link between AFB1 exposure and liver cirrhosis. Mitigation of aflatoxin exposure and a better understanding of additional environmental risk factors like pesticides may be necessary to reduce the disease burden in Ethiopia.

Response surface model to illustrate the benefits of tryptophan, melatonin, and N,N-dimethylglycine in quail chicks exposed to aflatoxin B1

A dose-response assay in a central composite design platform was conducted to investigate the responses (performance, immunity, and meat quality) of quail chicks to dietary tryptophan (Trp), melatonin (MEL), and N,N-dimethylglycine (DMG) exposed to aflatoxin B1 (AFB1). A total of 1,275 quail chicks were randomly allotted to 85-floor pens consisting of 17 treatments with 5 replicates and 15 birds per each pen. Dietary MEL and DMG had a different effect on growth rate and interacted with dietary Trp and AFB1 during the first 4 wk of age, while their effect disappeared at the last week of the experiment. Dietary Trp and AFB1 were only significant on the gain of quail chick after d 28 of the assay. During the second and third weeks of age, the reduction in feed intake caused by AFB1 attenuated by dietary MEL and DMG and dietary Trp profoundly affects feed intake in the last 2 wk of the experiment. Dietary MEL and DMG were effective on feed conversion ratio (FCR) during the second and third weeks of age. AFB1 decreased breast meat yield (BMY) and thigh meat yield (TMY), but the inclusion of either MEL or DMG removed the adverse effects of AFB1. Dietary Trp increased BMY, but it did not affect TMY. Increasing dietary Trp linearly increased the Lactobacillus bacteria (LAB) population, and AFB1 negatively impacts the LAB population. The inclusion of dietary DMG removed that negative effect on LAB. Although AFB1 decreased the antibody production against SRBC-antigen, increasing dietary Trp in intoxicated quails increased the plasma antibody in SRBC-challenged birds. At low levels of dietary Trp (0.15-0.19%), the addition of DMG increased malondialdehyde (MDA) production while increasing Trp reversed this adverse situation. In conclusion, these supplements may interact with AFB1 in younger chicks, and dietary Trp and AFB1 have a significant impact on the growth performance of quail chicks during the fifth and sixth week of age.

Mitigating the adverse effects of Aflatoxin B1 in LMH, IPEC-J2 and 3D4/21 cells by a novel integrated agent

This study was to evaluate the efficacy of TOXO-XL (XL), an integrated mycotoxin-mitigating agent, on aflatoxin B₁ (AFB₁)-induced damage in Leghorn male hepatoma (LMH), porcine jejunum epithelial cell line (IPEC-J2) and porcine alveolar macrophages (3D4/21) cells, and to explore its potential mechanisms. The results showed that 30% inhibition concentration (IC₃₀) of AFB₁ in LMH, IPEC-J2 and 3D4/21 cells was 0.5, 15.0, and 2.5 mg/L, respectively. Notably, cell viability, ROS, apoptosis and DNA lesion induced by AFB₁ (IC₃₀) could be ameliorated by the supplementation with XL at the dosage of 0.025, 0.025 and 0.005%, respectively. Additionally, the migration and phagocytosis abilities impaired by AFB₁ were also restored by XL in 3D4/21. Further experiments revealed that XL supplementation markedly attenuated AFB₁-induced inflammatory response by decreasing IL-1β, IL-6 and IL-10 in LMH, IL-6 in IPEC-J2 and IL-1β in 3D4/21 cells. Meanwhile, XL supplementation reversed the alterations of BAX, BCL-2 and caspase-3 induced by AFB₁ in the three cells, suggesting that AFB₁-induced apoptosis may be suppressed via the mitochondria-dependent pathway. Furthermore, XL may have a protective effect on the intestinal barrier through the restoration of occludin protein. Conclusively, these findings indicated that XL could alleviate AFB₁-induced cytotoxicity in the three cells, potentially through the regulation of cytokines, ROS, apoptotic and DNA damage signaling.

Protective role of curcumin on broiler liver by modulating aflatoxin B1-induced DNA methylation and CYPs expression

The purpose of this study was to investigate the role of epigenetic DNA methylation and CYPs expression in AFB1-exposed broiler liver and the protective effect of curcumin. Sixty-four one-day-old AA broilers were randomly divided into four groups, including control group, AFB1 group (1 mg/kg AFB1), curcumin + AFB1 group (1 mg/kg curcumin) and curcumin group (300 mg/kg curcumin). Histological observation, CYP450 enzyme activities, the expression levels of DNA methyltransferases and CYP450 enzymes, and the overall DNA methylation level in broiler liver were investigated. Dietary AFB1 was found to induce severe liver injury in broilers, upregulate the mRNA and protein expression of CYP450 enzymes (CYP1A1, CYP1A2 and CYP3A4) and the enzyme activities of CYP1A2 and CYP3A4. According to HPLC, qPCR and western blot analyses, the overall DNA methylation level and the mRNA and protein expression of DNA methyltransferases (DNMT1, DNMT3a and DNMT3b) in the liver were significantly increased after AFB1 exposure. Importantly, the Pearson test and correlation analysis data revealed that the overall DNA methylation level of broiler liver was positively correlated with DNMTs, while CYP1A1, CYP1A2 and CYP3A4 were negatively correlated. Surprisingly, curcumin supplementation strongly ameliorated AFB1-induced hepatotoxicity by restoring the histological changes, decreasing the expression and enzymatic activity of liver CYP450 enzymes (CYP1A1, CYP1A2, and CYP3A4), and increasing the overall DNA methylation level and the expression of DNMTs. Taken together, we concluded that curcumin could protect against AFB1-induced liver injury by mediating the effects of DNA methylation and CYPs expression.

Molecular mechanism and research progress on pharmacology of ferulic acid in liver diseases

Ferulic acid (FA) is a natural polyphenol, a derivative of cinnamic acid, widely found in Angelica, Chuanxiong and other fruits, vegetables and traditional Chinese medicine. FA contains methoxy, 4-hydroxy and carboxylic acid functional groups that bind covalently to neighbouring adjacent unsaturated Cationic C and play a key role in many diseases related to oxidative stress. Numerous studies have shown that ferulic acid protects liver cells and inhibits liver injury, liver fibrosis, hepatotoxicity and hepatocyte apoptosis caused by various factors. FA has protective effects on liver injury induced by acetaminophen, methotrexate, antituberculosis drugs, diosbulbin B and tripterygium wilfordii, mainly through the signal pathways related to TLR4/NF-κB and Keap1/Nrf2. FA also has protective effects on carbon tetrachloride, concanavalin A and septic liver injury. FA pretreatment can protect hepatocytes from radiation damage, protects the liver from damage caused by fluoride, cadmium and aflatoxin b1. At the same time, FA can inhibit liver fibrosis, inhibit liver steatosis and reduce lipid toxicity, improve insulin resistance in the liver and exert the effect of anti-liver cancer. In addition, signalling pathways such as Akt/FoxO1, AMPK, PPAR γ, Smad2/3 and Caspase-3 have been shown to be vital molecular targets for FA involvement in improving various liver diseases. Recent advances in the pharmacological effects of ferulic acid and its derivatives on liver diseases were reviewed. The results will provide guidance for the clinical application of ferulic acid and its derivatives in the treatment of liver diseases.

Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview

Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.

Aflatoxin B1 Degradation by Ery4 Laccase: From In Vitro to Contaminated Corn

Aflatoxins (AFs) are toxic secondary metabolites produced by Aspergillus spp. and are found in food and feed as contaminants worldwide. Due to climate change, AFs occurrence is expected to increase also in western Europe. Therefore, to ensure food and feed safety, it is mandatory to develop green technologies for AFs reduction in contaminated matrices. With this regard, enzymatic degradation is an effective and environmentally friendly approach under mild operational conditions and with minor impact on the food and feed matrix. In this work, Ery4 laccase, acetosyringone, ascorbic acid, and dehydroascorbic acid were investigated in vitro, then applied in artificially contaminated corn for AFB₁ reduction. AFB₁ (0.1 µg/mL) was completely removed in vitro and reduced by 26% in corn. Several degradation products were detected in vitro by UHPLC-HRMS and likely corresponded to AFQ₁, epi-AFQ₁, AFB₁-diol, or AFB₁dialehyde, AFB_2a, and AFM₁. Protein content was not altered by the enzymatic treatment, while slightly higher levels of lipid peroxidation and H₂O₂ were detected. Although further studies are needed to improve AFB₁ reduction and reduce the impact of this treatment in corn, the results of this study are promising and suggest that Ery4 laccase can be effectively applied for the reduction in AFB₁ in corn.

Sustainable and efficient method utilizing N-acetyl-L-cysteine for complete and enhanced ochratoxin A clearance by antagonistic yeast

With the increasing global climate change, ochratoxin A (OTA) pollution in food and environment has become a serious and potential risk element threatening food safety and human health. Biodegradation of mycotoxin is an eco-friendly and efficient control strategy. Still, research works are warranted to develop low-cost, efficient, and sustainable approaches to enhance the mycotoxin degradation efficiency of microorganisms. In this study, the activities of N-acetyl-L-cysteine (NAC) against OTA toxicity were evidenced, and its positive effects on the OTA degradation efficiency of antagonistic yeast, Cryptococcus podzolicus Y3 were verified. Co-culturing C. podzolicus Y3 with 10 mM NAC improved 100% and 92.6% OTA degradation rate into ochratoxin α (OTα) at 1 d and 2 d. The excellent promotion role of NAC on OTA degradation was observed even at low temperatures and alkaline conditions. C. podzolicus Y3 treated with OTA or OTA+NAC promoted reduced glutathione (GSH) accumulation. GSS and GSR genes were highly expressed after OTA and OTA+NAC treatment, contributing to GSH accumulation. In the early stages of NAC treatment, yeast viability and cell membrane were reduced, but the antioxidant property of NAC prevented lipid peroxidation. Our finding provides a sustainable and efficient new strategy to improve mycotoxin degradation by antagonistic yeasts, which could be applied to mycotoxin clearance.

The protective effect of 3-indolepropanoic acid on aflatoxin B1-induced systemic perturbation of the liver and kidney function in rats

Aflatoxin B1 (AFB1) is known to derange the hepatorenal system by redox, DNA adduct formation and apoptotic networks. Endogenous 3-indole propionic acid (3-IPA) is a metabolite of tryptophan metabolism by gut microbiota that can protect against redox imbalance, inflammation and cellular lipid damage. We investigated the beneficial effect of 3-IPA against AFB1-mediated organ toxicity in male rats post 28 days of consecutive treatment. The 3-IPA (25 and 50 mg/kg) was orally administered alongside AFB1 (50 μg/kg) treatment. Biochemical and enzyme-linked immunosorbent assays were utilised to examine biomarkers of hepatorenal function, oxidative status and inflammation. DNA damage and apoptosis were also assessed, and histological staining techniques were used to investigate hepatorenal tissues for pathological indicators. The 3-IPA supplementation abated AFB1-mediated increases in biomarkers of hepatic and renal dysfunction in rat serum. Co-administration of 3-IPA further reduced AFB1-induced redox imbalance (by upregulating antioxidant mediators and enzymes [GSH, TSH, Trx, Trx-R, SOD, CAT, GPx and GST]; reducing reactive oxygen species, lipid peroxidation and DNA adduct [RONS, LPO and 8-OH-dG] formation; suppressing pro-inflammatory and apoptotic mediators [XO, MPO, NO, IL-1β and Casp -9 and -3]; and upregulating the level of interleukin 10 (IL-10). Moreover, treatment with 3-IPA lessened hepatorenal tissue injuries. These findings suggest that augmenting 3-IPA endogenously from tryptophan metabolism may provide a novel strategy to forestall xenobiotics-mediated hepatorenal toxicity, including AFB1.

Alpha-class glutathione S-transferases involved in the detoxification of aflatoxin B1 in ducklings

The objective of this study was to identify the key glutathione S-transferase (GST) isozymes involved in the detoxification of Aflatoxin B₁ (AFB₁) in ducks' primary hepatocytes. The full-length cDNA encoding the 10 GST isozymes (GST, GST3, GSTM3, MGST1, MGST2, MGST3, GSTK1, GSTT1, GSTO1 and GSTZ1) were isolated/synthesized from ducks' liver and cloned into the pcDNA3.1(+) vector. The results showed that pcDNA3.1(+)-GSTs plasmids were successfully transferred into the ducks' primary hepatocytes and the mRNA of the 10 GST isozymes were overexpressed by 1.9-3274.7 times. Compared to the control, 75 μg/L (IC₃₀) or 150 μg/L (IC₅₀) AFB₁ treatment reduced the cell viability by 30.0-50.0% and increased the LDH activity by 19.8-58.2% in the ducks' primary hepatocytes. Notably, the AFB₁-induced changes in cell viability and LDH activity were mitigated by overexpression of GST and GST3. Compared to the cells treated with AFB₁, exo-AFB₁-8,9-epoxide (AFBO)-GSH, as the major detoxified product of AFB₁, was increased in the cells overexpression of GST and GST3. Moreover, the sequences, phylogenetic and domain analysis revealed that the GST and GST3 were orthologous to Meleagris gallopavo GSTA3 and GSTA4. In conclusion, this study found that the ducks' GST and GST3 were orthologous to Meleagris gallopavo GSTA3 and GSTA4, which were involved in the detoxification of AFB₁ in ducks' primary hepatocytes.

Effects of chronic low-dose aflatoxin B1 exposure in lactating Florida dairy goats

In the past few years there has been a growing trend in the prevalence of aflatoxins, attributable to climate change, in substances destined for animal feeding, together with an increase in dairy product consumption. These facts have triggered great concern in the scientific community over milk pollution by aflatoxin M₁. Therefore, our study aimed to determine the transfer of aflatoxin B₁ from the diet into milk as AFM₁ in goats exposed to different concentrations of AFB₁, and its possible effect on the production and serological parameters of this species. For this purpose, 18 goats in late lactation were divided into 3 groups (n = 6) and exposed to different daily doses of aflatoxin B₁ (T1 = 120 µg; T2 = 60 µg, and control = 0 µg), during 31 d. Pure aflatoxin B₁ was administered 6 h before each milking in an artificially contaminated pellet. The milk samples were taken individually in sequential samples. Milk yield and feed intake were recorded daily, and a blood sample was extracted on the last day of exposure. No aflatoxin M₁ was detected, either in the samples taken before the first administration, or in the control group ones. The aflatoxin M₁ concentration detected in the milk (T1 = 0.075 µg/kg; T2 = 0.035 µg/kg) increased significantly on a par with the amount of aflatoxin B₁ ingested. The amount of aflatoxin B₁ ingested did not have any influence on aflatoxin M₁ carryover (T1 = 0.066% and T2 = 0.060%), these being considerably lower than those described in dairy goats. Thus, we concluded that the concentration of aflatoxin M₁ in milk follows a linear relationship with respect to the aflatoxin B₁ ingested, and that the aflatoxin M₁ carryover was not affected by the administration of different aflatoxin B₁ doses. Similarly, no significant changes in the production parameters after chronic exposure to aflatoxin B₁ were observed, revealing a certain resistance of the goat to the possible effects of that aflatoxin.

Early-life AFB1 exposure: DNA methylation and hormone alterations

Aflatoxins are secondary metabolites of mold that contaminate food and feedstuff. They are found in various food including grains, nuts, milk and eggs. Aflatoxin B1 (AFB1) is the most poisonous and commonly found of the various types of aflatoxins. Exposures to AFB1 start early in life viz. in utero, during breastfeeding, and during weaning through the waning foods which are mainly grain based. Several studies have shown that early-life exposures to various contaminants may have various biological effects. In this chapter, we reviewed the effects of early-life AFB1 exposures on changes in hormone and DNA methylation. In utero AFB1 exposure results in alterations in steroid and growth hormones. Specifically, the exposure results in a reduction in testosterone levels later in life. The exposure also affects the methylation of various genes that are significant in growth, immune, inflammation, and signaling pathways.

Maternal dietary exposure to mycotoxin aflatoxin B1 promotes intestinal immune alterations and microbiota modifications increasing infection susceptibility in mouse offspring

Mycotoxins are secondary metabolites produced by fungi occurring in food that are toxic to animals and humans. Early-life mycotoxins exposure has been linked to diverse pathologies. However, how maternal exposure to mycotoxins impacts on the intestinal barrier function of progeny has not been explored. Here, exposure of pregnant and lactating C57Bl/6J female mice to aflatoxin B₁ (AFB₁; 400 μg/kg body weight/day; 3 times a week) in gelatine pellets, from embryonic day (E)11.5 until weaning (postnatal day 21), led to gut immunological changes in progeny. The results showed an overall increase of lymphocyte number in intestine, a reduction of expression of epithelial genes related to microbial defence, as well as a decrease in cytokine production by intestinal type 2 innate lymphoid cells (ILC2). While susceptibility to chemically induced colitis was not worsened, immune alterations were associated with changes in gut microbiota and with a higher vulnerability to infection by the protozoan Eimeria vermiformis at early-life. Together these results show that maternal dietary exposure to AFB₁ can dampen intestinal barrier homeostasis in offspring decreasing their capability to tackle intestinal pathogens. These data provide insights to understand AFB₁ potential harmfulness in early-life health in the context of intestinal infections.

Comparative Assessment of Different Yeast Cell Wall-Based Mycotoxin Adsorbents Using a Model- and Bioassay-Based In Vitro Approach

Frequently reported occurrences of deoxynivalenol (DON), beauvericin (BEA), and, to a lesser extent, ochratoxin A (OTA) and citrinin (CIT) in ruminant feed or feedstuff could represent a significant concern regarding feed safety, animal health, and productivity. Inclusion of yeast cell wall-based mycotoxin adsorbents in animal feeds has been a common strategy to mitigate adverse effects of mycotoxins. In the present study, an in vitro approach combining adsorption isotherm models and bioassays was designed to assess the efficacy of yeast cell wall (YCW), yeast cell wall extract (YCWE), and a postbiotic yeast cell wall-based blend (PYCW) products at the inclusion rate of 0.5% (w/v) (ratio of adsorbent mass to buffer solution volume). The Hill's adsorption isotherm model was found to best describe the adsorption processes of DON, BEA, and CIT. Calculated binding potential for YCW and YCWE using the Hill's model exhibited the same ranking for mycotoxin adsorption, indicating that BEA had the highest adsorption rate, followed by DON and CIT, which was the least adsorbed. PYCW had the highest binding potential for BEA compared with YCW and YCWE. In contrast, the Freundlich isotherm model presented a good fit for OTA adsorption by all adsorbents and CIT adsorption by PYCW. Results indicated that YCW was the most efficacious for sequestering OTA, whereas YCWE was the least efficacious. PYCW showed greater efficacy at adsorbing OTA than CIT. All adsorbents exhibited high adsorption efficacy for BEA, with an overall percentage average of bound mycotoxin exceeding 60%, whereas moderate efficacies for the other mycotoxins were observed (up to 37%). Differences in adsorbent efficacy of each adsorbent significantly varied according to experimental concentrations tested for each given mycotoxin (p < 0.05). The cell viability results from the bioassay using a bovine mammary epithelial cell line (MAC-T) indicated that all tested adsorbents could potentially mitigate mycotoxin-related damage to bovine mammary epithelium. Results from our studies suggested that all tested adsorbents had the capacity to adsorb selected mycotoxins in vitro, which could support their use to mitigate their effects in vivo.

Human CYP1B1 enzyme-mediated, AhR enhanced activation of aflatoxin B1 for its genotoxicity in human cells

Aflatoxin B1 (AFB1) is a human procarcinogen known to be activated by cytochrome P450 (CYP) 1A2 and 3A4. In a previous study AFB1 caused chromosomal rearrangement in a yeast strain genetically engineered for stably expressing human CYP1B1. Yet, further verification of the effect of AFB1 in human cells, a potential role of the aryl hydrocarbon receptor (AhR), and CYP1B1-catalyzed AFB1 metabolism remain unidentified. In this study, a human hepatocyte (L-02) line and a human lymphoblastoid (TK6) cell line were genetically engineered for the expression of human CYP1B1, producing L-02-hCYP1B1 and TK6-hCYP1B1, respectively. They were exposed to AFB1 and analyzed for the formation of micronucleus and elevation of γ-H2AX (indicating double-strand DNA breaks); the metabolites formed by CYP1B1 from AFB1 after incubation of AFB1 with human CYP1B1 isoenzyme microsomes were determined by LC-MS. The results showed significantly more potent induction of micronucleus by AFB1 in L-02-hCYP1B1 and TK6-hCYP1B1 than in the parental (L-02 and TK6) cells, and the effects were reduced by (E)- 2,3',4,5'-tetramethoxystilbene, a specific CYP1B1 inhibitor. In the AFB1- CYP1B1 microsomes incubations AFM1, a known stable metabolite of AFB1, was detected. Moreover, in L-02 and TK6 cells, AFB1 apparently increased the protein levels of AhR, ANRT and CYP1B1, and caused the nuclear translocation of AhR and ARNT, the latter effect being blocked by BAY-218 (an inhibitor of AhR). In conclusion, this study indicates that human CYP1B1 is capable of metabolically activating AFB1 through the AhR signaling pathway.

Interactions of Mycotoxin Alternariol with Cytochrome P450 Enzymes and OATP Transporters

Alternariol (AOH) is an emerging mycotoxin produced by Alternaria strains. The acute toxicity of the mycotoxin is low; however, chronic exposure to AOH may result in the development of endocrine disruptor and/or carcinogenic effects. The toxicokinetic properties of AOH have barely been characterized. Therefore, in this study, we aimed to investigate its interactions with CYP (1A2, 2C9, 2C19, 2D6, and 3A4) enzymes and OATP (1A2, 1B1, 1B3, and 2B1) transporters employing in vitro enzyme assays and OATP overexpressing cells, respectively. Our results demonstrated that AOH is a strong inhibitor of CYP1A2 (IC₅₀ = 0.15 μM) and CYP2C9 (IC₅₀ = 7.4 μM). Based on the AOH depletion assays in the presence of CYP enzymes, CYP1A2 is mainly involved, while CYP2C19 is moderately involved in the CYP-catalyzed biotransformation of the mycotoxin. AOH proved to be a strong inhibitor of each OATP transporter examined (IC₅₀ = 1.9 to 5.4 μM). In addition, both direct and indirect assays suggest the involvement of OATP1B1 in the cellular uptake of the mycotoxin. These findings promote the deeper understanding of certain toxicokinetic interactions of AOH.

Human Breast Milk Contamination with Aflatoxins, Impact on Children's Health, and Possible Control Means: A Review

Aflatoxins are natural toxicants produced mainly by species of the Aspergillus genus, which contaminate virtually all feeds and foods. Apart from their deleterious health effects on humans and animals, they can be secreted unmodified or carried over into the milk of lactating females, thereby posing health risks to suckling babies. Aflatoxin M1 (AFM1) is the major and most toxic aflatoxin type after aflatoxin B1 (AFB1). It contaminates human breast milk upon direct ingestion from dairy products or by carry-over from the parent molecule (AFB1), which is hydroxylated in the liver and possibly in the mammary glands by cytochrome oxidase enzymes and then excreted into breast milk as AFM1 during lactation via the mammary alveolar epithelial cells. This puts suckling infants and children fed on this milk at a high risk, especially that their detoxifying activities are still weak at this age essentially due to immature liver as the main organ responsible for the detoxification of xenobiotics. The occurrence of AFM1 at toxic levels in human breast milk and associated health conditions in nursing children is well documented, with developing countries being the most affected. Different studies have demonstrated that contamination of human breast milk with AFM1 represents a real public health issue, which should be promptly and properly addressed to reduce its incidence. To this end, different actions have been suggested, including a wider and proper implementation of regulatory measures, not only for breast milk but also for foods and feeds as the upstream sources for breast milk contamination with AFM1. The promotion of awareness of lactating mothers through the organization of training sessions and mass media disclosures before and after parturition is of a paramount importance for the success of any action. This is especially relevant that there are no possible control measures to ensure compliance of lactating mothers to specific regulatory measures, which can yet be appropriate for the expansion of breast milk banks in industrialized countries and emergence of breast milk sellers. This review attempted to revisit the public health issues raised by mother milk contamination with AFM1, which remains undermined despite the numerous relevant publications highlighting the needs to tackle its incidence as a protective measure for the children physical and mental health.

Possible Mechanisms of the Interplay between Drugs and Mycotoxins-Is There a Possible Impact?

Mycotoxin contamination is a global food safety issue leading to major public health concerns. Repeated exposure to multiple mycotoxins not only has repercussions on human health but could theoretically also lead to interactions with other xenobiotic substances-such as drugs-in the body by altering their pharmacokinetics and/or pharmacodynamics. The combined effects of chronic drug use and mycotoxin exposure need to be well understood in order to draw valid conclusions and, in due course, to develop guidelines. The aim of this review is to focus on food contaminants, more precisely on mycotoxins, and drugs. First, a description of relevant mycotoxins and their effects on human health and metabolism is presented. The potential for interactions of mycotoxins with drugs using in vitro and in vivo animal experiments is summarized. Predictive software tools for unraveling mycotoxin-drug interactions are proposed and future perspectives on this emerging topic are highlighted with a view to evaluate associated risks and to focus on precision medicine. In vitro and in vivo animal studies have shown that mycotoxins affect CYP450 enzyme activity. An impact from drugs on mycotoxins mediated via CYP450-enzymes is plausible; however, an impact of mycotoxins on drugs is less likely considering the much smaller dose exposure to mycotoxins. Drugs that are CYP450 perpetrators and/or substrates potentially influence the metabolism of mycotoxins, metabolized via these CYP450 enzymes. To date, very little research has been conducted on this matter. The only statistically sound reports describe mycotoxins as victims and drugs as perpetrators in interactions; however, more analysis on mycotoxin-drug interactions needs to be performed.

Aflatoxins contents determination in some foodstuffs in Burkina Faso and human health risk assessment

Aflatoxins are produced by fungi of the genus Aspergillus that colonize many foodstuffs during agricultural production, harvesting, transportation, storage, and food processing. In view of these aflatoxins toxicity to humans, their presence in foods such as cereals and oilseeds constitutes a major challenge for global food security, health and nutrition. This study was therefore initiated to assess the level of aflatoxin contamination of various foodstuffs sold in urban and semi-urban markets in Burkina Faso, and to evaluate the carcinogenic risk which the consuming population is exposed to. Two hundred and twelve foodstuff samples were collected in two large cities (Ouagadougou and Bobo Dioulasso) and three semi urban localities (Cinkansé, Dakola and Niangoloko). Aflatoxins contents in foodstuffs were determined by immunoaffinity chromatography and human health risk assessment was performed by using the Monte Carlo algorithm. The aflatoxins contents determination showed that 41.50% of studied samples were contaminated with concentrations up to 182.28 μg/kg for AFB1 in peanuts. Chronic Daily Intake, calculated based on the consumption patterns assumed in this study, was estimated to be higher in large cities (CDI = 33.68 μg/kg bw in Ouagadougou and 10.18 μg/kg bw in Bobo Dioulasso) than in semi urban localities (CDI = 4.29 μg/kg bw in Cinkansé, CDI = 0.39 μg/kg bw in Dakola and CDI = 0.18 μg/kg bw in Niangoloko). The MOE determination showed that the sorghum meal and whole grain maize consumption was associated to the carcinogenic risk for public health in large cities (the percentile 95 of MOE = 3316 for rice, 4511 for peanuts, 3334 for sorghum meal and 4530 for whole grain maize). In semi urban localities, no carcinogenic risk was observed to public health. These results should inspire the country's sanitary and agricultural authorities to undertake actions to fight against the agricultural food products contamination by aflatoxins in order to safeguard the population's health.