Preliminary data on citrinin kinetics in humans and their use to estimate citrinin exposure based on biomarkers

Development and validation of an analytical method for determination of citrinin in red rice and red yeast rice-based food supplements by ultra-high performance liquid chromatography tandem mass spectrometry

Citrinin is a hepato-nephrotoxic mycotoxin produced by fungal species. The Monascus purpureus fungus plays a crucial role in the fermentation of red rice to produce red yeast rice-based food supplements, which represent the primary source of human exposure to citrinin. In this study, a simple and sensitive analytical method was successfully developed and validated for the citrinin determination in these products. The extraction process involved a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) step and citrinin determination by ultra high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). The proposed method provided satisfactory linearity, percentage of recovery from 82 to 104% with relative standard deviations (RSD) lower than 14%, and limits of detection and quantification of 0.07 μg/Kg and 0.24 μg/kg, respectively. Among the 14 samples analyzed, citrinin was found in two red rice samples (0.24 and 0.46 μg/kg) and in six food supplements (from 0.44 to 87 μg/kg).

Citrinin Provoke DNA Damage and Cell-Cycle Arrest Related to Chk2 and FANCD2 Checkpoint Proteins in Hepatocellular and Adenocarcinoma Cell Lines

Citrinin (CIT), a polyketide mycotoxin produced by Penicillium, Aspergillus, and Monascus species, is a contaminant that has been found in various food commodities and was also detected in house dust. Several studies showed that CIT can impair the kidney, liver, heart, immune, and reproductive systems in animals by mechanisms so far not completely elucidated. In this study, we investigated the CIT mode of action on two human tumor cell lines, HepG2 (hepatocellular carcinoma) and A549 (lung adenocarcinoma). Cytotoxic concentrations were determined using an MTT proliferation assay. The genotoxic effect of sub-IC50 concentrations was investigated using the alkaline comet assay and the impact on the cell cycle using flow cytometry. Additionally, the CIT effect on the total amount and phosphorylation of two cell-cycle-checkpoint proteins, the serine/threonine kinase Chk2 and Fanconi anemia (FA) group D2 (FANCD2), was determined by the cell-based ELISA. The data were analyzed using GraphPad Prism statistical software. The CIT IC50 for HepG2 was 107.3 µM, and for A549, it was >250 µM. The results showed that sensitivity to CIT is cell-type dependent and that CIT in sub-IC50 and near IC50 induces significant DNA damage and cell-cycle arrest in the G2/M phase, which is related to the increase in total and phosphorylated Chk2 and FANCD2 checkpoint proteins in HepG2 and A549 cells.

Monitoring Mycotoxin Exposure in Food-Producing Animals (Cattle, Pig, Poultry, and Sheep)

Food-producing animals are exposed to mycotoxins through ingestion, inhalation, or dermal contact with contaminated materials. This exposure can lead to serious consequences for animal health, affects the cost and quality of livestock production, and can even impact human health through foods of animal origin. Therefore, controlling mycotoxin exposure in animals is of utmost importance. A systematic literature search was conducted in this study to retrieve the results of monitoring exposure to mycotoxins in food-producing animals over the last five years (2019-2023), considering both external exposure (analysis of feed) and internal exposure (analysis of biomarkers in biological matrices). The most commonly used analytical technique for both approaches is LC-MS/MS due to its capability for multidetection. Several mycotoxins, especially those that are regulated (ochratoxin A, zearalenone, deoxynivalenol, aflatoxins, fumonisins, T-2, and HT-2), along with some emerging mycotoxins (sterigmatocystin, nivalenol, beauvericin, enniantins among others), were studied in 13,818 feed samples worldwide and were typically detected at low levels, although they occasionally exceeded regulatory levels. The occurrence of multiple exposure is widespread. Regarding animal biomonitoring, the primary objective of the studies retrieved was to study mycotoxin metabolism after toxin administration. Some compounds have been suggested as biomarkers of exposure in the plasma, urine, and feces of animal species such as pigs and poultry. However, further research is required, including many other mycotoxins and animal species, such as cattle and sheep.

HLA gene variations and mycotoxin toxicity: Four case reports

Mycotoxins are produced by certain molds that can cause many health effects. We present four human cases of prolonged consistent mycotoxins exposure linked to genetic variations in human leukocyte antigen (HLA) alleles. The HLA-DR/DQ isotype alleles are linked to mycotoxins susceptibility due to the lack of proper immune response; individuals with these alleles are poor eliminators of mycotoxins from their system. Four subjects with variations in their HLA-DR alleles were exposed to mycotoxins from living in mold-infested houses and experienced persistent mold-related symptoms long after moving out from the mold-infested houses and only exposed to the levels of molds found in the ambient air. From one of the subjects, two urine samples were collected ~ 18 months apart after the cessation of exposure. Urinary elimination rate was extremely slow for two of the mycotoxins (ochratoxin A [OTA] and mycophenolic acid [MPA]) detected in both samples. In 18 months, decline in OTA level was only ~ 3-fold (estimated t½ of ~ 311 days) and decline in MPA level was ~ 11-fold (estimated t½ of ~ 160 days), which was ~ 10- and ~ 213-fold slower than expected in individuals without HLA-DR alleles, respectively. We estimated that ~ 4.3 and ~ 2.2 years will be required for OTA and MPA to reach < LLQ in urine, respectively. Three other subjects with variations in HLA-DR alleles were members of a family who lived in a mold-infested house for 4 years. They kept experiencing mold-related issues >2 years after moving to a non-mold-infested house. Consistent exposure was confirmed by the presence of several mycotoxins in urine >2 years after the secession of higher than background (from outdoor ambient air) exposure. This was consistent with the extremely slow elimination of mycotoxins from their system. Variations in HLA-DR alleles can, consequently, make even short periods of exposure to chronic exposure scenarios with related adverse health effects. It is, therefore, important to determine genetic predisposition as a reason for prolonged/lingering mold-related symptoms long after the cessation of higher than background exposure. Increased human exposure to mycotoxins is expected from increased mold infestation that is anticipated due to rising CO2, temperature, and humidity from the climate change with possibly increased adverse health effects, especially in individuals with genetic susceptibility to mold toxicity.

Probing the Interactions of 31 Mycotoxins with Xanthine Oxidase: Alternariol, Alternariol-3-Sulfate, and α-Zearalenol Are Allosteric Inhibitors of the Enzyme

Mycotoxins are frequent toxic contaminants in foods and beverages, causing a significant health threat. Interactions of mycotoxins with biotransformation enzymes (e.g., cytochrome P450 enzymes, sulfotransferases, and uridine 5'-diphospho-glucuronosyltransferases) may be important due to their possible detoxification or toxic activation during enzymatic processes. Furthermore, mycotoxin-induced enzyme inhibition may affect the biotransformation of other molecules. A recent study described the strong inhibitory effects of alternariol and alternariol-9-methylether on the xanthine oxidase (XO) enzyme. Therefore, we aimed to test the impacts of 31 mycotoxins (including the masked/modified derivatives of alternariol and alternariol-9-methylether) on XO-catalyzed uric acid formation. Besides the in vitro enzyme incubation assays, mycotoxin depletion experiments and modeling studies were performed. Among the mycotoxins tested, alternariol, alternariol-3-sulfate, and α-zearalenol showed moderate inhibitory actions on the enzyme, representing more than tenfold weaker impacts compared with the positive control inhibitor allopurinol. In mycotoxin depletion assays, XO did not affect the concentrations of alternariol, alternariol-3-sulfate, and α-zearalenol in the incubates; thus, these compounds are inhibitors but not substrates of the enzyme. Experimental data and modeling studies suggest the reversible, allosteric inhibition of XO by these three mycotoxins. Our results help the better understanding of the toxicokinetic interactions of mycotoxins.

Food Toxicity of Mycotoxin Citrinin and Molecular Mechanisms of Its Potential Toxicity Effects through the Implicated Targets Predicted by Computer-Aided Multidimensional Data Analysis

The mycotoxin citrinin, which can contaminate food, is a major global concern. Citrinin is regarded as an inevitable pollutant in foods and feed since fungi are widely present in the environment. To identify contentious toxicity and lessen its severity by understanding the targets of citrinin in the human body and the impacted biosynthetic pathways, we analyzed the production of citrinin from Aspergillus flavus and Penicillium notatum and used a thorough bioinformatics analysis to characterize the toxicity and predict genes and protein targets for it. The predicted median fatal dosage (LD50) for citrinin was 105 mg/kg weight, and it belonged to toxicity class 3 (toxic if swallowed). Citrinin was found to be well absorbed by human intestinal epithelium and was a Pgp nonsubstrate (permeability glycoprotein), which means that once it is absorbed, it cannot be pumped out, hence leading to bioconcentration or biomagnification in the human body. The main targets of toxicity were casp3, TNF, IL10, IL1B, BAG3, CCNB1, CCNE1, and CDC25A, and the biological pathways implicated were signal transduction involved in DNA damage checkpoints, cellular and chemical responses to oxidative stress, DNA damage response signal transduction by P53, stress-activated protein kinase signaling cascade, netrin–UNC5B signaling, PTEN gene regulation, and immune response. Citrinin was linked to neutrophilia, squamous cell carcinoma, Fanconi anemia, leukemia, hepatoblastoma, and fatty liver diseases. The transcription factors E2F1, HSF1, SIRT1, RELA, NFKB, JUN, and MYC were found to be responsible. When data mining was performed on citrinin targets, the top five functional descriptions were a cell’s response to an organic cyclic compound, the netrin–UNC5B signaling pathway, lipids and atherosclerosis, thyroid cancer, and controlling the transcription of the PTEN gene.

Citrinin inhibits the function of Leydig cells in male rats in prepuberty

Citrinin, a mycotoxin existing in fruits, has nephrotoxicity, hepatotoxicity and embryotoxicity. The effects of citrinin on Leydig cell development in prepuberty remains unclear. Male Sprague-Dawley rats were gavaged with 0, 1, 2.5, and 5 mg/kg citrinin from postnatal days 21-28. Citrinin at 5 mg/kg significantly decreased serum testosterone levels, while increasing serum LH and FSH levels. Citrinin at 1-5 mg/kg markedly downregulated Hsd17b3 and HSD17B3 expression, while upregulating Srd5a1 (SRD5A1) and Akr1c14 (AKR1C14) expression at 2.5 and/or 5 mg/kg. Citrinin at 5 mg/kg also significantly increased PCNA-labeling index in Leydig cells. Citrinin at 5 mg/kg significantly raised testicular MDA amount, whiling at 2.5 and 5 mg/kg downregulating SOD1 and SOD2 expression. Citrinin at 5 mg/kg markedly decreased the ratio of Bcl2 to Bax, in consistent with the increased apoptosis in Leydig cells judged by TUNEL assay. Enzymatic assay revealed that citrinin inhibited rat testicular HSD3B1 activity at 100 µM and HSD17B3 activity at 10-100 μM. Citrinin at 50 μM and higher also induced reactive oxygen species (ROS) and apoptosis of R2C cell line. In conclusion, citrinin inhibits Leydig cell development at multiple levels via different mechanisms and oxidative stress partially plays a role.

Citrinin Exposure in Germany: Urine Biomarker Analysis in Children and Adults

Citrinin (CIT), a mycotoxin known to exert nephrotoxicity, is a contaminant in food and feed. Since CIT contamination is not regularly analyzed, data on its occurrence and especially levels in food commodities are insufficient for conducting a conventional exposure assessment. Yet, human biomonitoring, i.e., an analysis of CIT and its metabolite dihydrocitrinone (DH-CIT) in urine samples allows to estimate exposure. This study investigated CIT exposure in young (2-14 years) and adult (24-61 years) residents of three federal states in Germany. A total of 179 urine samples from children and 142 from adults were collected and analyzed by a targeted LC-MS/MS based method for presence of CIT and DH-CIT. At least one of the biomarkers was detected and quantified in all urines, which indicated a widespread dietary exposure to the mycotoxin in Germany. Interestingly, the biomarker concentrations of CITtotal (sum of CIT and DH-CIT) were higher in children's urine (range 0.05-7.62 ng/mL; median of 0.54 ng/mL) than in urines from adults (range 0.04-3.5 ng/mL; median 0.3 ng/mL). The biomarker levels (CITtotal) of individual urines served to calculate the probable daily CIT intake, for comparison to a value of 0.2 µg/kg bw/day defined as 'level of no concern for nephrotoxicity' by the European Food Safety Authority. The median exposure of German adults was 0.013 µg/kg b.w., with only one urine donor exceeding this provisional tolerable daily intake (pTDI) for CIT. The median exposure of children was 0.05 µg/kg bw per day (i.e., 25% of the pTDI); however, CIT exposure in 12 individuals (6.3% of our study group) exceeded the limit value, with a maximum intake of 0.46 µg/kg b.w. per day. In conclusion, these results show evidence for non-negligible exposure to CIT in some individuals in Germany, mainly in children. Therefore, further biomonitoring studies and investigations aimed to identify the major sources of CIT exposure in food commodities are required.

Antarctic fungi with antibiotic potential isolated from Fort William Point, Antarctica

The Antarctic continent is one of the most inhospitable places on earth, where living creatures, mostly represented by microorganisms, have specific physiological characteristics that allow them to adapt to the extreme environmental conditions. These physiological adaptations can result in the production of unique secondary metabolites with potential biotechnological applications. The current study presents a genetic and antibacterial characterization of four Antarctic fungi isolated from soil samples collected in Pedro Vicente Maldonado Scientific Station, at Fort William Point, Greenwich Island, Antarctica. Based on the sequences of the internal transcribed spacer (ITS) region, the fungi were identified as Antarctomyces sp., Thelebolus sp., Penicillium sp., and Cryptococcus gilvescens. The antibacterial activity was assessed against four clinical bacterial strains: Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Staphylococcus aureus, by a modified bacterial growth inhibition assay on agar plates. Results showed that C. gilvescens and Penicillium sp. have potential antibiotic activity against all bacterial strains. Interestingly, Thelebolus sp. showed potential antibiotic activity only against E. coli. In contrast, Antarctomyces sp. did not show antibiotic activity against any of the bacteria tested under our experimental conditions. This study highlights the importance of conservation of Antarctica as a source of metabolites with important biomedical applications.

Neurotoxicity of mycotoxin citrinin: Novel evidence in developing zebrafish and underlying mechanisms in human neuron cells

Citrinin (CTN) is a mycotoxin that is found as a contaminant in various types of food/feed grains and fermented food supplements. Previous studies have already established the nephrotoxicity and hepatotoxicity of CTN, but the neurotoxicity of CTN has not been clearly examined. In this study, CTN at 2-20 μM was first found to interfere with the neural ganglia formation and locomotive behavior of embryonic zebrafish, a vertebrate animal model, at 24 hpf and 6 dpf, respectively. Further exposure of human neuroblastoma SH-SY5Y cells to 10 and 20 μM CTN for 72 h indicated that pathways responsible for neuron differentiation and projection guidance were down-regulated while oxidative stress and electron transport chain pathways were up-regulated based on the enrichment results of GSEA in the transcriptomic profiling. PCR analysis verified that CTN significantly down-regulated the expression of marker genes involved in neuron differentiation and synaptic signaling. CTN at the doses impairing cellular neurite outgrowth did not trigger mitochondrial oxidative stress and dysfunction. The neurotoxic mechanisms of CTN provide new information that is valuable in the assessment of CTN-related health risk for the general public.

Assessment of multiple mycotoxin exposure and its association with food consumption: a human biomonitoring study in a pregnant cohort in rural Bangladesh

Aflatoxins (AFs), ochratoxin A (OTA), citrinin (CIT), fumonisin B1 (FB1), zearalenone (ZEN), and deoxynivalenol (DON) are mycotoxins that may contaminate diets, especially in low-income settings, with potentially severe health consequences. This study investigates the exposure of 439 pregnant women in rural Bangladesh to 35 mycotoxins and their corresponding health risks and links their exposure to certain foods and local stimulants. Overall, 447 first-morning urine samples were collected from pregnant women between July 2018 and November 2019. Mycotoxin biomarkers were quantified by DaS-HPLC-MS/MS. Urinary concentration of frequently occurring mycotoxins was used to estimate dietary mycotoxin exposure. Median regression analyses were performed to investigate the association between the consumption of certain foods and local stimulants, and urinary concentration of frequently occurring mycotoxins. Only in 17 of 447 urine samples (4%) were none of the investigated mycotoxins detected. Biomarkers for six major mycotoxins (AFs, CIT, DON, FB1, OTA, and ZEN) were detected in the urine samples. OTA (95%), CIT (61%), and DON (6%) were most frequently detected, with multiple mycotoxins co-occurring in 281/447 (63%) of urine samples. Under the lowest exposure scenario, dietary exposure to OTA, CIT, and DON was of public health concern in 95%, 16%, and 1% of the pregnant women, respectively. Consumption of specific foods and local stimulants-betel nut, betel leaf, and chewing tobacco-were associated with OTA, CIT, and DON urine levels. In conclusion, exposure to multiple mycotoxins during early pregnancy is widespread in this rural community and represents a potential health risk for mothers and their offspring.

Coconut Cream Agar as a simple and rapid semiquantitative method to screen citrinin-producing Monascus spp. isolates isolated from red fermented rice

Red fermented rice (RFR) is produced using Monascus spp. This product has some health benefits. However, RFR can also contain the mycotoxin, citrinin (CIT) and that has adverse effects on human health. The objective of the study was to develop a simple and rapid screening method for the detection of Monascus spp. isolates that can produce CIT by using Coconut Cream Agar (CCA). RFR was spread onto CCA and other media and incubated at 30 °C for 7 days. All the media were observed daily under ultraviolet (UV) light and any Monascus spp. colony that produced light blue fluorescence was recorded as a CIT-producer. Two different isolates (MF1 and MS1) isolated from CCA were selected for further analysis. All (100%; 10/10 plates) of CCA inoculated with MF1 produced light blue fluorescence after incubation for 4 days, meanwhile 30% (3/10 plates) of MS1 produced weak fluorescence on CCA after incubation for 7 days. Isolates MF1 and MS1 were identified as M. purpureus with the ability to produce CIT by having polyketide synthase (pksCT) and transcriptional regulator (ctnA) genes. CIT was quantified by high-performance liquid chromatography (HPLC). CCA is a simple and rapid method to detect CIT-producers of Monascus spp.

The role of ER stress and ATP/AMPK in oxidative stress meditated hepatotoxicity induced by citrinin

Citrinin, a secondary metabolite, can pose serious risks to the environment and organisms, but its hepatotoxic mechanisms are still unclear. Histopathological and ultrastructural results showed that citrinin-induced liver injury in Kunming mice, and the mechanism of citrinin-induced hepatotoxicity was studied in L02 cells. Firstly, citrinin mades L02 cell cycle arrest in G2/M phase by inhibition of cyclin B1, cyclin D1, cyclin-dependent kinases 2 (CDK2), and CDK4 expression. Secondly, citrinin inhibits proliferation and promotes apoptosis of L02 cells via disruption of mitochondria membrane potential, increase Bax/Bcl-2 ration, activation of caspase-3, 9, and enhance lactate dehydrogenase (LDH) release. Then, citrinin inhibits superoxide dismutase (SOD) activity and increases the accumulation of malondialdehyde (MDA) and reactive oxygen species (ROS), resulting oxidative damage in L02 cells; upregulates the protein expression of binding immunoglobulin protein (Bip), C/EBP homologous protein (CHOP), PKR-like ER kinase (PERK) and activating transcription factor6 (ATF6), inducing ER stress in L02 cells; increases the phosphorylation of AMP-activated protein kinase (AMPK) and decreases the content of adenosine-triphosphate (ATP), activating AMPK pathway in L02 cells. Eventually, pretreatment with NAC, an ROS inhibitor, alleviates citrinin-induced cell cycle G2/M arrest and apoptosis by inhibiting ROS-mediated ER stress; pretreatment with 4-PBA, an ER stress inhibitor, reversed ER stress and p-AMPK; pretreatment with dorsomorphin, an AMPK inhibitor, decreases citrinin-induced cell cycle G2/M arrest and apoptosis. In summary, citrinin induces cell cycle arrest and apoptosis to aggravate liver injury by activating ROS-ER stress-AMPK signaling pathway.

Biomonitoring of ochratoxin A, 2'R-ochratoxin A and citrinin in human blood serum from Switzerland

Biomonitoring of mycotoxins and their metabolites in biological fluids is increasingly used to assess human exposure. In this study, biomarkers of ochratoxin A (OTA) and citrinin (CIT) exposure were determined in a large number of serum samples from healthy blood donors in Switzerland. In 2019, 700 samples from different regions were obtained. From 240 donors, a second sample (taken 2-9 months later) was available for analysis. Moreover, 355 blood donor samples from 2005 from all regions in Switzerland and 151 additional samples from the southern Swiss region of Ticino from 2005 could be analysed.OTA, 2'R-ochratoxin A (2'R-OTA), ochratoxin alpha (OTα), CIT and dihydrocitrinone (DH-CIT) were analysed using validated targeted methods including precipitation and online SPE clean-up.OTA and 2'R-OTA were frequently detected (OTA in 99%; 2'R-OTA in 51% of the tested samples). The mean concentration in all positive samples was 0.4 ng/mL for OTA and 0.2 ng/mL for 2'R-OTA. OTα was not detected in any sample above the limit of quantification (LOQ). In contrast to OTA, CIT and DH-CIT were only quantifiable in 2% and 0.1% of the samples, respectively. No significant trend was observed between the samples from 2005 and the more recent samples, but OTA concentrations were usually higher in serum samples from the southern Swiss region of Ticino and in males compared to females.Our extensive data fit well within the framework of previously published values for the healthy adult European population.

Citrinin-Induced Hepatotoxicity in Mice Is Regulated by the Ca2+/Endoplasmic Reticulum Stress Signaling Pathway

Citrinin (CTN) is a mycotoxin found in crops and agricultural products and poses a serious threat to human and animal health. The aim of this study is to investigate the hepatotoxicity of CTN in mice and analyze its mechanisms from Ca2+-dependent endoplasmic reticulum (ER) stress perspective. We showed that CTN induced histopathological damage, caused ultrastructural changes in liver cells, and induced abnormal values of biochemical laboratory tests of some liver functions in mice. Treatment with CTN could induce nitric oxide (NO), malondialdehyde (MDA), and reactive oxygen species (ROS) accumulation in mice, accompanied with losses of activities of superoxide dismutase (SOD) and catalase (CAT), levels of glutathione (GSH), and capacities of total antioxidant (T-AOC), resulting in oxidative stress in mice. Furthermore, CTN treatment significantly increased Ca2+ accumulation, upregulated protein expressions of ER stress-mediated apoptosis signal protein (glucose regulated protein 78 (GRP78/BIP), C/EBP-homologous protein (CHOP), Caspase-12, and Caspase-3), and induced hepatocyte apoptosis. These adverse effects were counteracted by 4-phenylbutyric acid (4-PBA), an ER stress inhibitor. In summary, our results showed a possible underlying molecular mechanism for CTN that induced hepatocyte apoptosis in mice by the regulation of the Ca2+/ER stress signaling pathway.

Mycotoxins in Serum and 24-h Urine of Vegans and Omnivores from the Risks and Benefits of a Vegan Diet (RBVD) Study

Scope Vegans might have a higher exposure to mycotoxins due to their heightened consumption of typical mycotoxin containing food sources. Yet, data on internal exposure among vegans in comparison to omnivores are currently lacking. Methods and Results This cross-sectional study included 36 vegans and 36 omnivores (50% females, 30-60 years). A set of 28 and 27 mycotoxins was analyzed in 24-h urine and serum samples, respectively, by validated multi-mycotoxin methods (HPLC-MS/MS). Ochratoxin A (OTA), 2'R-OTA, and enniatin B in serum as well as deoxynivalenol-glucuronide in 24-h urine were quantified in 57 to 100% of the samples. Serum OTA levels were twofold higher in vegans than in omnivores (median 0.24 versus 0.12 ng/mL; P <0.0001). No further significant differences were observed. Serum OTA levels were associated with intake of "vegan products" (r = 0.50, P <0.0001) and "pasta & rice" (r = 0.33, P = 0.006). Sensitivity analyses advise cautious interpretation. Furthermore, serum levels of 2'R-OTA were related to coffee consumption (r = 0.64, P <0.0001). Conclusion Our results indicate a higher exposure of vegans to OTA, but not to other mycotoxins. However, larger studies with repeated measurements are required to better evaluate the exposure to mycotoxins from plant-based diets. This article is protected by copyright. All rights reserved.

Recent Progress in Rapid Determination of Mycotoxins Based on Emerging Biorecognition Molecules: A Review

Mycotoxins are secondary metabolites produced by fungal species, which pose significant risk to humans and livestock. The mycotoxins which are produced from Aspergillus, Penicillium, and Fusarium are considered most important and therefore regulated in food- and feedstuffs. Analyses are predominantly performed by official laboratory methods in centralized labs by expert technicians. There is an urgent demand for new low-cost, easy-to-use, and portable analytical devices for rapid on-site determination. Most significant advances were realized in the field bioanalytical techniques based on molecular recognition. This review aims to discuss recent progress in the generation of native biomolecules and new bioinspired materials towards mycotoxins for the development of reliable bioreceptor-based analytical methods. After brief presentation of basic knowledge regarding characteristics of most important mycotoxins, the generation, benefits, and limitations of present and emerging biorecognition molecules, such as polyclonal (pAb), monoclonal (mAb), recombinant antibodies (rAb), aptamers, short peptides, and molecularly imprinted polymers (MIPs), are discussed. Hereinafter, the use of binders in different areas of application, including sample preparation, microplate- and tube-based assays, lateral flow devices, and biosensors, is highlighted. Special focus, on a global scale, is placed on commercial availability of single receptor molecules, test-kits, and biosensor platforms using multiplexed bead-based suspension assays and planar biochip arrays. Future outlook is given with special emphasis on new challenges, such as increasing use of rAb based on synthetic and naïve antibody libraries to renounce animal immunization, multiple-analyte test-kits and high-throughput multiplexing, and determination of masked mycotoxins, including stereoisomeric degradation products.

Testing the extraction of 12 mycotoxins from aqueous solutions by insoluble beta-cyclodextrin bead polymer

Mycotoxins are toxic metabolites of filamentous fungi; they are common contaminants in numerous foods and beverages. Cyclodextrins are ring-shaped oligosaccharides, which can form host-guest type complexes with certain mycotoxins. Insoluble beta-cyclodextrin bead polymer (BBP) extracted successfully some mycotoxins (e.g., alternariol and zearalenone) from aqueous solutions, including beverages. Therefore, in this study, we aimed to examine the ability of BBP to remove other 12 mycotoxins (including aflatoxin B1, aflatoxin M1, citrinin, dihydrocitrinone, cyclopiazonic acid, deoxynivalenol, ochratoxin A, patulin, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol) from different buffers (pH 3.0, 5.0, and 7.0). Our results showed that BBP can effectively extract citrinin, dihydrocitrinone, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol at each pH tested. However, for the removal of ochratoxin A, BBP was far the most effective at pH 3.0. Based on these observations, BBP may be a suitable mycotoxin binder to extract certain mycotoxins from aqueous solutions for decontamination and/or for analytical purposes.

Urinary Biomarkers of Mycotoxin Induced Nephrotoxicity-Current Status and Expected Future Trends

The intensifying world-wide spread of mycotoxigenic fungal species has increased the possibility of mycotoxin contamination in animal feed and the human food chain. Growing evidence shows the deleterious toxicological effects of mycotoxins from infants to adults, while large population-based screening programs are often missing to identify affected individuals. The kidney functions as the major excretory system, which makes it particularly vulnerable to nephrotoxic injury. However, few studies have attempted to screen for kidney injury biomarkers in large, mycotoxin-exposed populations. As a result, there is an urgent need to screen them with sensitive biomarkers for potential nephrotoxicity. Although a plethora of biomarkers have been tested to estimate the harmful effects of a wide spectrum of toxicants, β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are currently the dominant biomarkers employed routinely in environmental toxicology research. Nevertheless, kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as useful and informative markers to reveal mycotoxin induced nephrotoxicity. In this opinion article we consider the nephrotoxic effects of mycotoxins, the biomarkers available to detect and quantify the kidney injuries caused by them, and to recommend biomarkers to screen mycotoxin-exposed populations for renal damage.

Assessment of Citrinin in Spices and Infant Cereals Using Immunoaffinity Column Clean-Up with HPLC-Fluorescence Detection

Historically, the analysis of citrinin has mainly been performed on cereals such as red yeast rice; however, in recent years, more complex and abnormal commodities such as spices and infant foods are becoming more widely assessed. The aim of this study was to develop and validate clean-up methods for spices and cereal-based infant foods using a citrinin immunoaffinity column before HPLC analysis with fluorescence detection. Each method developed was validated with a representative matrix, spiked at various citrinin concentrations, based around European Union (EU) regulations set for ochratoxin A (OTA), with recoveries >80% and % RSD < 9% in all cases. The limit of detection (LOD) and the limit of quantification (LOQ) were established at 1 and 3 µg/kg for spices and 0.1 and 0.25 µg/kg for infant cereals, respectively. These methods were then tested across a variety of spices and infant food products to establish efficacy with high recoveries >75% and % RSD < 5% across all matrices assessed. Therefore, these methods proved suitable for providing effective clean-up of spices and infant cereals, enabling reliable quantification of citrinin detected. Samples such as nutmeg and infant multigrain porridge had higher levels of citrinin contamination than anticipated, indicating that citrinin could be a concern for public health. This highlighted the need for close monitoring of citrinin contamination in these commodities, which may become regulated in the future.

Overall Exposure of European Adult Population to Mycotoxins by Statistically Modelled Biomonitoring Data

This study presents the exposure scenario to mycotoxins of adult population throughout Europe. The urinary biomarkers values were obtained by modelling data from two European projects. Exposure to AFB1, OTA, CIT, FBs, DON, NIV and T2/HT2 are presented. The main output obtained refers to a concern for public health about AFM1, FBs, T2/HT2 and NIV, and low concern for OTA, DON and CIT. The margin of exposure for AFM1 did not respect the reference value of 10,000 considered of low priority for risk; for Fusarium toxins, FBs and T2/HT2, probable daily intake (PDI) values resulted about ten times higher than their tolerable daily intake and NIV presented the most critical situation with a calculated PDI 30 times higher than the reference TDI value. North and South Europe scenarios were also depicted by clustering biomonitoring data. OTA and DON showed to be prevalent in Northern countries and the opposite was noticed for ZEN, higher in Southern countries. The critical issues of the availability of records feeding the dataset and of the accuracy of excretion rate for some mycotoxins are source of uncertainty for the reliability of the outputs, nevertheless the time is ripe for asking for more concrete HBM values and/or HBM-HBGV which would help in interpreting the burden of mycotoxins in Europe.

Citrinin Dietary Exposure Assessment Approach through Human Biomonitoring High-Resolution Mass Spectrometry-Based Data

Citrinin (CIT) is a scarcely studied mycotoxin within foodstuffs, so the biomonitoring of this toxin and its metabolite dihydrocitrinone (DH-CIT) in biological samples represents the main alternative to estimate the exposure. Hence, this study aimed to evaluate the presence of CIT and DH-CIT in 300 urine samples from Italian individuals in order to assess the exposure. Quantification was performed through an ultrahigh-performance liquid chromatography high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS)-based methodology. CIT was quantified in 47% of samples (n = 300) up to 4.0 ng/mg Crea (mean = 0.29 ng/mg Crea), whereas DH-CIT was quantified in 21% of samples up to 2.5 ng/mg Crea (mean = 0.39 ng/mg Crea). Considering different age groups, average exposure ranged from 8% to 40% of the provisional tolerable daily intake, whereas four individuals surpassed the limits suggested by the European Food Safety Authority. These results revealed non-negligible exposure levels to CIT, encouraging further investigation in foodstuffs monitoring studies.

Volumetric Absorptive Microsampling as an Alternative Tool for Biomonitoring of Multi-Mycotoxin Exposure in Resource-Limited Areas

Biomonitoring of biological samples arises as an effective tool to evaluate the exposure to mycotoxins in the population. Owing to the wide range of advantages, there is a growing interest in the use of non- and minimally invasive alternative sampling strategies, such as dried blood spot sampling or volumetric absorptive microsampling (VAMS). A VAMS-based multi-mycotoxin method was developed and validated for 24 different mycotoxins. Method validation was based on the Bioanalytical Method Validation Guideline of the Food and Drug Administration from the United States and for most of the studied mycotoxins, the results of the performance characteristics were in agreement with the criteria of the European Commission Decision 2002/657/EC. The recovery for the different mycotoxins was not haematocrit dependent and remained acceptable after storing the VAMS for 7 and 21 days at refrigeration temperature (4 °C) and room temperature, demonstrating that VAMS could be applied to assess mycotoxin exposure in blood in resource-limited areas, where there may be a delay between sampling and analysis. Finally, a comparison between VAMS and a procedure for liquid whole blood analysis, performed on 20 different blood samples, did not result in missed exposed cases for VAMS. Moreover, both methods detected similar levels of ochratoxin A, ochratoxin alpha, zearalenone and aflatoxin B1. Given all the benefits associated with VAMS and the developed method, VAMS sampling may serve as an alternative to conventional venous sampling to evaluate multiple mycotoxin exposure.

Citrinin in Foods and Supplements: A Review of Occurrence and Analytical Methodologies

Citrinin (CIT) deserves attention due to its known toxic effects in mammalian species and its widespread occurrence in food commodities, often along with ochratoxin A, another nephrotoxic mycotoxin. Human exposure, a key element in assessing risk related to food contaminants, depends upon mycotoxin contamination levels in food and on food consumption. Commercial supplements, commonly designated as red rice, usually used in daily diets in Asiatic countries due to their medicinal properties, may pose a health problem as a result of high CIT levels. In addition to the worldwide occurrence of CIT in foods and supplements, a wide range of several analytical and detection techniques with high sensitivity, used for evaluation of CIT, are reviewed and discussed in this manuscript. This review addresses the scientific literature regarding the presence of CIT in foods of either vegetable or animal origin, as well as in supplements. On what concerns analytical methodologies, sample extraction methods, such as shaking extraction and ultrasonic assisted extraction (UAE), clean-up methods, such as liquid-liquid extraction (LLE), solid phase extraction (SPE) and Quick, Easy, Cheap, Effective, Rugged and Safe (QuECHERS), and detection and quantification methods, such as thin layer chromatography (TLC), high performance liquid chromatography (HPLC), capillary electrophoresis (CE), biosensors, and ELISA, are also reviewed.

Dietary exposure assessment and risk characterization of citrinin and ochratoxin A in Belgium

Exposure to mycotoxins is a worldwide problem. To ensure public health, it is imperative to characterize the risks related to these toxins. The present study aims to conduct a dietary exposure assessment of citrinin (CIT) and ochratoxin A (OTA) in the Belgian population using consumption data of a variety of foodstuffs. A total of 367 food samples from different food categories were collected in Belgian supermarkets and analysed for CIT and OTA using a validated liquid chromatography-tandem mass spectrometry method. Daily CIT and OTA exposure to the Belgian population was calculated based on the analytical results and food consumption data in three age categories (3-9, 10-17 and 18-64 years), obtained from a national food consumption survey. Furthermore, a risk characterization was performed for CIT, in which no intake values exceeded the tolerable daily intake (TDI) of 200 ng kg^-1 bw day^-1, indicating no health risk. However, a CIT intake level of 187 ng kg^-1 bw day^-1 was detected for children in the age category of 3-9 years in the worst case scenario for rice, indicating that rice consumption could contain a potential health hazard for young children. For OTA, a potential health risk was detected in several food categories (biscuits, croissants, rice, flour, meat imitates, herbs and spices) in the higher percentiles (P99) or at maximum found concentrations when calculating the margin of exposure (MoE) for neoplastic effects. An attempt to perform a cumulative health risk assessment for both toxins was done. Although a high number of uncertainties is involved, combined margin of exposure (MoET) values indicated a potential health risk related to the combined exposure to CIT and OTA. For the first time, our study demonstrated the potential health risks of CIT and OTA after individual and combined exposure, in particular related to rice consumption. Moreover, further research is recommended concerning multiple mycotoxin exposure in young children.

A Study of Carry-Over and Histopathological Effects after Chronic Dietary Intake of Citrinin in Pigs, Broiler Chickens and Laying Hens

Citrinin (CIT) is a polyketide mycotoxin occurring in a variety of food and feedstuff, among which cereal grains are the most important contaminated source. Pigs and poultry are important livestock animals frequently exposed to mycotoxins, including CIT. Concerns are rising related to the toxic, and especially the potential nephrotoxic, properties of CIT. The purpose of this study was to clarify the histopathological effects on kidneys, liver, jejunum and duodenum of pigs, broiler chickens and laying hens receiving CIT contaminated feed. During 3 weeks, pigs (n = 16) were exposed to feed containing 1 mg CIT/kg feed or to control feed (n = 4), while 2 groups of broiler chickens and laying hens (n = 8 per group) received 0.1 mg CIT/kg feed (lower dose group) and 3 or 3.5 mg CIT/kg feed (higher dose group), respectively, or control feed (n = 4). CIT concentrations were quantified in plasma, kidneys, liver, muscle and eggs using a validated ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method. Kidneys, liver, duodenum and jejunum were evaluated histologically using light microscopy, while the kidneys were further examined using transmission electron microscopy (TEM). Histopathology did not reveal major abnormalities at the given contamination levels. However, a significant increase of swollen and degenerated mitochondria in renal cortical cells from all test groups were observed (p < 0.05). These observations could be related to oxidative stress, which is the major mechanism of CIT toxicity. Residues of CIT were detected in all collected tissues, except for muscle and egg white from layers in the lowest dose group, and egg white from layers in the highest dose group. CIT concentrations in plasma ranged between 0.1 (laying hens in lower dose group) and 20.8 ng/mL (pigs). In tissues, CIT concentrations ranged from 0.6 (muscle) to 20.3 µg/kg (liver) in pigs, while concentrations in chickens ranged from 0.1 (muscle) to 70.2 µg/kg (liver). Carry-over ratios from feed to edible tissues were between 0.1 and 2% in pigs, and between 0.1 and 6.9% in chickens, suggesting a low contribution of pig and poultry tissue-derived products towards the total dietary CIT intake for humans.

Recent advances in analytical methods for the determination of citrinin in food matrices

Citrinin is a toxic small organic molecule produced as a secondary metabolite by fungi types Penicillium, Monascus and Aspergillus and is known to contaminate various food commodities during postharvest stages of food production. During the last 10 years, most reported methods for citrinin analysis employed enzyme-linked immunosorbent assays or high-performance liquid chromatography. Over this same time period, liquid extraction, solid-phase extraction, dispersive liquid-liquid microextraction and QuEChERS were the most cited sample preparation and clean-up methods. In this review the advantages and disadvantages of the various sample preparation, separation and detection methods for citrinin analysis over the last decade are evaluated. Furthermore, current trends, emerging technologies and the future prospects of these methods are discussed.

Mycotoxin exposure and human cancer risk: A systematic review of epidemiological studies

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case-control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle-Ottawa scale. Animal, cross-sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case-control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin-contaminated foods and primary liver cancer risk was verified. Two case-control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case-control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose-dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in-depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence-based public health strategies.

Reviewing the Analytical Methodologies to Determine the Occurrence of Citrinin and its Major Metabolite, Dihydrocitrinone, in Human Biological Fluids

Until now, the available data regarding citrinin (CIT) levels in food and the consumption of contaminated foods are insufficient to allow a reliable estimate of intake. Therefore, biomonitoring configuring analysis of parent compound and/or metabolites in biological fluids, such as urine or blood, is being increasingly applied in the assessment of human exposure to CIT and its metabolite, dihydrocitrinone (DH-CIT). Most studies report urinary levels lower for the parent compound when compared with DH-CIT. A high variability either in the mean levels or in the inter-individual ratios of CIT/DH-CIT between the reported studies has been found. Levels of DH-CIT in urine were reported as being comprised between three to seventeen times higher than the parent mycotoxin. In order to comply with this objective, sensitive analytical methodologies for determining biomarkers of exposure are required. Recent development of powerful analytical techniques, namely liquid chromatography coupled to mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography (UHPLC-MS/MS) have facilitated biomonitoring studies, mainly in urine samples. In the present work, evidence on human exposure to CIT through its occurrence and its metabolite, in biological fluids, urine and blood/plasma, in different countries, is reviewed. The analytical methodologies usually employed to evaluate trace quantities of these two molecules, are also presented. In this sense, relevant data on sampling (size and pre-treatment), extraction, cleanup and detection and quantification techniques and respective chromatographic conditions, as well as the analytical performance, are evidenced.

Comprehensive toxicokinetic analysis reveals major interspecies differences in absorption, distribution and elimination of citrinin in pigs and broiler chickens

A comprehensive toxicokinetic analysis of citrinin (CIT) revealed interspecies differences for all toxicokinetic parameters and in absolute oral bioavailability. Oral bioavailability for CIT was complete for broilers (113-131%), while ranging from 37 to 44% in pigs. CIT was more rapidly absorbed in pigs (T_max = 0.92 h) compared to broiler chickens (T_max = 7.33 h). The elimination of CIT was slower in pigs (T_1/2el = 26.81 h after intravenous (IV) administration) compared to chickens (T_1/2el = 1.97 h after IV administration), due to the striking difference in clearance (Cl_iv=9.87 mL/h/kg for pigs versus Cl_iv = 863.09 mL/h/kg for broilers). Also, the volume of distribution differed significantly between pigs (Vd = 0.30 L/kg after IV administration) and chickens (Vd = 2.46 L/kg after IV administration). However, plasma protein binding did not differ statistically significant (91-98%). It is imperative to further investigate biotransformation and elimination pathways in different species, including humans.

Mycotoxin exposure assessments in a multi-center European validation study by 24-hour dietary recall and biological fluid sampling

The European Food Consumption Validation (EFCOVAL) project includes 600 men and women from Belgium, the Czech Republic, France, the Netherlands, and Norway, who had given serum and 24-hour urine samples, and completed 24-hour dietary recall (24-HDR) interviews. Consumption, according to 24-HDR, was matched against the European Food Safety Authority (EFSA) databases of mycotoxin contaminations, via the FoodEx1 standard classifications, producing an indirect external estimate of dietary mycotoxin exposure. Direct, internal measurements of dietary mycotoxin exposure were made in serum and urine by ultra-performance liquid chromatography coupled to tandem mass spectrometry. For the first time, mycotoxin exposures were thoroughly compared between two 24-HDRs, and two 24-hour urine samples collected during the same days covered by the 24-HDRs. These measurements were compared to a single-time point serum measurement to investigate evidence of chronic mycotoxin exposure. According to 24-HDR data, all 600 individuals were exposed to between 4 and 34 mycotoxins, whereof 10 found to exceed the tolerable daily intake. Correlations were observed between two time points, and significant correlations were observed between concentrations in serum and urine. However, only acetyldeoxynivalenol, ochratoxin A, and sterigmatocystin were found to have significant positive correlations between 24-HDR exposures and serum, while aflatoxin G1 and G2, HT-2 toxin, and deoxynivalenol were associated between concurrent 24-HDR and 24-hour urine. Substantial agreements on quantitative levels between serum and urine were observed for the groups Type B Trichothecenes and Zearalenone. Further research is required to bridge the interpretation of external and internal exposure estimates of the individual on a time scale of hours. Additionally, metabolomic profiling of dietary mycotoxin exposures could help with a comprehensive assessment of single time-point exposures, but also with the identification of chronic exposure biomarkers. Such detailed characterization informs population exposure assessments, and aids in the interpretation of epidemiological health outcomes related to multi-mycotoxin exposure.

Human Biomonitoring of Mycotoxins in Blood, Plasma and Serum in Recent Years: A Review

This manuscript reviews the state-of-the-art regarding human biological monitoring (HBM) of mycotoxins in plasma serum and blood samples. After a comprehensive and systematic literature review, with a focus on the last five years, several aspects were analyzed and summarized: a) the biomarkers analyzed and their encountered levels, b) the analytical methodologies developed and c) the relationship between biomarker levels and some illnesses. In the literature reviewed, aflatoxin B1-lysine (AFB1-lys) and ochratoxin A (OTA) in plasma and serum were the most widely studied mycotoxin biomarkers for HBM. Regarding analytical methodologies, a clear increase in the development of methods for the simultaneous determination of multiple mycotoxins has been observed. For this purpose, the use of liquid chromatography (LC) methodologies, especially when coupled with tandem mass spectrometry (MS/MS) or high resolution mass spectrometry (HRMS), has grown. A high percentage of the samples analyzed for OTA or aflatoxin B1 (mostly as AFB1-lys) in the reviewed papers were positive, demonstrating human exposure to mycotoxins. This review confirms the importance of mycotoxin human biomonitoring and highlights the important challenges that should be faced, such as the inclusion of other mycotoxins in HBM programs, the need to increase knowledge of mycotoxin metabolism and toxicokinetics, and the need for reference materials and new methodologies for treating samples. In addition, guidelines are required for analytical method validation, as well as equations to establish the relationship between human fluid levels and mycotoxin intake.

Analyses of biomarkers of exposure to nephrotoxic mycotoxins in a cohort of patients with renal tumours

The Czech Republic occupies the first place in the world in the frequency of renal and other urinary tract tumours, but their aetiology is unknown. To explore whether carcinogenic and nephrotoxic mycotoxins may contribute to kidney diseases in the Czech population, biomarkers of ochratoxin A (OTA) and citrinin (CIT) exposure were determined in biological specimens from a cohort of 50 patients with malignant renal tumours. Biomarker analyses in blood and urine samples used validated targeted methods for measuring OTA and CIT plus dihydrocitrinone (DH-CIT) after enrichment of analytes by specific immunoaffinity clean-up. OTA and CIT plus its metabolite DH-CIT were frequently detected in patient urine samples (OTA 62%; CIT 91%; DH-CIT 100%). The concentration ranges in urine were 1-27.8 ng/L for OTA, 2-87 ng/L for CIT and 2-160 ng/L for DH-CIT. The analyses of blood samples revealed also a frequent co-occurrence of OTA and CIT, in the ranges of 40-870 ng/L serum for OTA and 21-182 ng/L plasma for CIT. This first analysis of biomarkers in blood and urine samples of Czech patients revealed no major differences in comparison with published data for the general healthy Czech and European populations. Nonetheless, a frequent co-occurrence of CIT and OTA biomarkers in patient samples may be of interest with regard to potential interactions with other risk factors for renal disease.

Citrinin biomarkers: a review of recent data and application to human exposure assessment

The mycotoxin citrinin (CIT) deserves attention due to its known toxic effects in mammalian species and a widespread occurrence in food commodities, often along with ochratoxin A, another nephrotoxic mycotoxin. Human exposure, a key element in assessing risks related to these food contaminants, depends upon mycotoxin levels in food and on food consumption. Yet, data available for CIT levels in food are insufficient for reliable intake estimates. Now biomonitoring, i.e., analysis of parent compound and/or metabolites in human specimen (blood, urine, breast milk), is increasingly used to investigate mycotoxin exposure. Biomonitoring requires sensitive methods for determining biomarkers of exposure, combined with kinetic data to conclude on the absorbed internal dose in an individual. Recent advances in LC-MS/MS-based analytical techniques have facilitated biomonitoring studies on the occurrence of CIT biomarkers in body fluids, mainly in urine samples. This review compiles evidence on human exposure to CIT in different countries, on CIT kinetics in humans, and on biomarker-based CIT intake estimates. Human CIT exposures are discussed in light of an intake value defined as 'level of no concern for nephrotoxicity' by the European Food Safety Agency, and some uncertainties in the toxicological data base. Further studies on CIT, including biomarker-based studies are warranted along with regular food surveys for this mycotoxin to protect consumers against undesirable health effects.

Interaction of Dihydrocitrinone with Native and Chemically Modified Cyclodextrins

Citrinin (CIT) is a nephrotoxic mycotoxin produced by Aspergillus, Penicillium, and Monascus genera. It appears as a contaminant in grains, fruits, and spices. After oral exposure to CIT, its major urinary metabolite, dihydrocitrinone (DHC) is formed, which can be detected in human urine and blood samples. Cyclodextrins (CDs) are ring-shaped molecules built up from glucose units. CDs can form host-guest type complexes with several compounds, including mycotoxins. In this study, the complex formation of DHC with native and chemically modified beta- and gamma-cyclodextrins was tested at a wide pH range, employing steady-state fluorescence spectroscopic and modeling studies. The weakly acidic environment favors the formation of DHC-CD complexes. Among the CDs tested, the quaternary-ammonium-γ-cyclodextrin (QAGCD) formed the most stable complexes with DHC. However, the quaternary-ammonium-β-cyclodextrin (QABCD) induced the strongest enhancement in the fluorescence signal of DHC. Our results show that some of the chemically modified CDs are able to form stable complexes with DHC (logK = 3.2–3.4) and the complex formation can produce even a 20-fold increase in the fluorescence signal of DHC. Considering the above-listed observations, CD technology may be a promising tool to increase the sensitivity of the fluorescence detection of DHC.

DNA damage in rat kidneys and liver upon subchronic exposure to single and combined ochratoxin A and citrinin

The study aimed to check whether ochratoxin A (OTA) and citrinin (CIT) increase DNA damage in the kidney and liver of male Wistar rats (alkaline comet assay), clarify the oxidative nature of DNA damage (hOGG1-modified comet assay), and verify whether resveratrol (RSV) could ameliorate OTA+CIT-induced genotoxicity. Rats were treated orally with OTA (0.125 and 0.250 mg/kg bodyweight (bw)) and CIT (2 mg/kg bw), OTA+CIT combinations and OTA+CIT+RSV (0.250+2+20 mg/kg bw) for 21 days. Both alkaline and hOGG1-modified comet assay showed that DNA damage was more severe in rat kidneys than in liver following mycotoxin treatment. Alkaline comet assay revealed a higher intensity of DNA damage, particularly as measured by tail intensity in the kidneys. Both tail length and tail intensity were OTA dose-dependent, but in combined OTA+CIT treatment these values were similar to CIT alone and lower than in animals treated with single OTA, possibly due to induction of apoptosis. hOGG1-modified comet showed that OTA+CIT evoked greater oxidative DNA damage than single mycotoxins. RSV did not reduce DNA damage measured by alkaline comet assay, but hOGG1-modified comet showed that RSV ameliorated OTA+CIT genotoxicity in the kidneys. Apart from oxidative stress, other mechanisms of DNA damage are involved in OTA and CIT genotoxicity. In rat kidneys RSV can reduce but not overcome oxidative DNA damage induced by combined OTA and CIT.

Interaction of the mycotoxin metabolite dihydrocitrinone with serum albumin

Citrinin (CIT) is a nephrotoxic mycotoxin produced by Penicillium, Monascus, and Aspergillus species. CIT appears as a contaminant in cereals, cereal-based products, fruits, nuts, and spices. During the biotransformation of CIT, its major urinary metabolite dihydrocitrinone (DHC) is formed. Albumin interacts with several compounds (including mycotoxins) affecting their tissue distribution and elimination. CIT-albumin interaction is known; however, the complex formation of DHC with albumin has not been reported previously. In this study, we aimed to investigate the interaction of DHC with albumin, employing fluorescence spectroscopy, circular dichroism, and molecular modeling studies. Furthermore, species differences and thermodynamics of the interaction as well as the effects of albumin on the acute in vitro toxicity of DHC and CIT were also tested. Our main observations/conclusions are as follows: (1) Fluorescence signal of DHC is strongly enhanced by albumin. (2) Formation of DHC-albumin complexes is supported by both fluorescence spectroscopic and circular dichroism studies. (3) DHC forms similarly stable complexes with human albumin (K~10⁵ L/mol) as CIT. (4) DHC-albumin interaction did not show significant species differences (tested with human, bovine, porcine, and rat albumins). (5) Based on modeling studies and investigations with site markers, DHC occupies the Heme binding site (subdomain IB) on human albumin. (6) The presence of albumin significantly decreased the acute in vitro cytotoxic effects of both DHC and CIT on MDCK cell line.