Association of aflatoxin with gallbladder cancer in a case-control study nested within a Chinese cohort.

We evaluated whether aflatoxin B1 (AFB1 ) exposure was associated with later risk of developing gallbladder cancer (GBC). We measured AFB1 -lysine albumin adducts in baseline samples from the Shanghai Cohort Study of 18 244 men aged 45 to 64 years (recruited 1986-1989). We included 84 GBC cases with sufficient serum and 168 controls matched on age at sample collection, date of blood draw and residence. We calculated adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for detectable vs non-detectable AFB1 -lysine albumin adducts and gallbladder cancer. AFB1 -lysine albumin adducts were detected in 50.0% of GBC cases, and risk of GBC was twice as high in those with detectable vs undetectable levels (OR = 2.0, 95% CI = 1.0-3.9). ORs ranged from 1.8 (95% CI = 0.75-4.3) for 0.5 to <1.75 pg/mg vs undetectable adduct levels to 2.2 (95% CI = 0.91-5.6) for >3.36 pg/mg vs undetectable, suggesting a dose-response (Ptrend = .05). When restricted to cases diagnosed before the median time to diagnosis after blood draw (18.4 years), results were similar (OR = 2.2, 95% CI = 0.80-5.8) to those for the entire follow-up duration. The OR was 9.4 (95% CI = 1.7-51.1) for individuals with detectable AFB1 -lysine albumin adducts and self-reported gallstones compared to individuals with neither. Participants with detectable AFB1 -lysine albumin adducts at baseline had increased risk of developing GBC, replicating the previously observed association between AFB1 exposure and providing the first evidence of temporality.

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.

Resolution of eicosanoid/cytokine storm prevents carcinogen and inflammation-initiated hepatocellular cancer progression.

Toxic environmental carcinogens promote cancer via genotoxic and nongenotoxic pathways, but nongenetic mechanisms remain poorly characterized. Carcinogen-induced apoptosis may trigger escape from dormancy of microtumors by interfering with inflammation resolution and triggering an endoplasmic reticulum (ER) stress response. While eicosanoid and cytokine storms are well-characterized in infection and inflammation, they are poorly characterized in cancer. Here, we demonstrate that carcinogens, such as aflatoxin B1 (AFB1), induce apoptotic cell death and the resulting cell debris stimulates hepatocellular carcinoma (HCC) tumor growth via an "eicosanoid and cytokine storm." AFB1-generated debris up-regulates cyclooxygenase-2 (COX-2), soluble epoxide hydrolase (sEH), ER stress-response genes including BiP, CHOP, and PDI in macrophages. Thus, selective cytokine or eicosanoid blockade is unlikely to prevent carcinogen-induced cancer progression. Pharmacological abrogation of both the COX-2 and sEH pathways by PTUPB prevented the debris-stimulated eicosanoid and cytokine storm, down-regulated ER stress genes, and promoted macrophage phagocytosis of debris, resulting in suppression of HCC tumor growth. Thus, inflammation resolution via dual COX-2/sEH inhibition is an approach to prevent carcinogen-induced cancer.

Impact of Sequencing Depth and Library Preparation on Toxicological Interpretation of RNA-Seq Data in a "Three-Sample" Scenario.

While RNA-sequencing (RNA-seq) has emerged as a standard approach in toxicogenomics, its full potential in gaining underlying toxicological mechanisms is still not clear when only three biological replicates are used. This "three-sample" study design is common in toxicological research, particularly in animal studies during preclinical drug development. Sequencing depth (the total number of reads in an experiment) and library preparation are critical to the resolution and integrity of RNA-seq data and biological interpretation. We used aflatoxin b1 (AFB1), a model toxicant, to investigate the effect of sequencing depth and library preparation in RNA-seq on toxicological interpretation in the "three-sample" scenario. We also compared different gene profiling platforms (RNA-seq, TempO-seq, microarray, and qPCR) using identical liver samples. Well-established mechanisms of AFB1 toxicity served as ground truth for our comparative analyses. We found that a minimum of 20 million reads was sufficient to elicit key toxicity functions and pathways underlying AFB1-induced liver toxicity using three replicates and that identification of differentially expressed genes was positively associated with sequencing depth to a certain extent. Further, our results showed that RNA-seq revealed toxicological insights from pathway enrichment with overall higher statistical power and overlap ratio, compared with TempO-seq and microarray. Moreover, library preparation using the same methods was important to reproducing the toxicological interpretation.

Aflatoxin Exposure during Early Life Is Associated with Differential DNA Methylation in Two-Year-Old Gambian Children.

Background: DNA methylation is an epigenetic control mechanism that may be altered by environmental exposures. We have previously reported that in utero exposure to the mycotoxin and liver carcinogen aflatoxin B1 from the maternal diet, as measured using biomarkers in the mothers' blood, was associated with differential DNA methylation in white blood cells of 6-month-old infants from The Gambia. Methods: Here we examined aflatoxin B1-associated differential DNA methylation in white blood cells of 24-month-old children from the same population (n = 244), in relation to the child's dietary exposure assessed using aflatoxin albumin biomarkers in blood samples collected at 6, 12 and 18 months of age. HM450 BeadChip arrays were used to assess DNA methylation, with data compared to aflatoxin albumin adduct levels using two approaches; a continuous model comparing aflatoxin adducts measured in samples collected at 18 months to DNA methylation at 24 months, and a categorical time-dose model that took into account aflatoxin adduct levels at 6, 12 and 18 months, for comparison to DNA methylation at 24 months. Results: Geometric mean (95% confidence intervals) for aflatoxin albumin levels were 3.78 (3.29, 4.34) at 6 months, 25.1 (21.67, 29.13) at 12 months and 49.48 (43.34, 56.49) at 18 months of age. A number of differentially methylated CpG positions and regions were associated with aflatoxin exposure, some of which affected gene expression. Pathway analysis highlighted effects on genes involved with with inflammatory, signalling and growth pathways. Conclusions: This study provides further evidence that exposure to aflatoxin in early childhood may impact on DNA methylation.

The Intervention and Mechanism of Action for Aloin against Subchronic Aflatoxin B1 Induced Hepatic Injury in Rats.

As a class of difurancoumarin compounds with similar structures, aflatoxins (AF) are commonly found in the environment, soil, and food crops. AF pose a serious threat to the health of humans, poultry, and livestock. This study aimed to investigate the neuroprotective effect and detailed mechanism of aloin on hepatic injury induced by subchronic AFB1 in rats. The result showed that aloin could significantly inhibit the decrease in food intake, body weight growth, immune organ index, and serum albumin content caused by long-term AFB1 exposure. Meanwhile, aloin reduced the level of serum liver function and improved renal swelling and pathological changes of liver tissue. Aloin could also inhibit liver lipid peroxidation and improve liver antioxidant capacity. Further investigation revealed that aloin inhibited the activity and expression of hepatic CYP1A2 and CYP3A4 and down-regulated IL-1ß expression in subchronic AFB1-induced liver injury rats. The above study demonstrated that aloin played an important role in blocking or delaying the development process of subchronic AFB1-induced hepatotoxicity. Therefore, aloin is considered to have a potential role as a protective agent against AFB1.

Effect of sequestering agents based on a Saccharomyces cerevisiae fermentation product and clay on the ruminal bacterial community of lactating dairy cows challenged with dietary aflatoxin B1.

This study was conducted to examine the effects of clay (CL) and Saccharomyces cerevisiae fermentation product (SCFP) on the ruminal bacterial community of Holstein dairy cows challenged with aflatoxin B1 (AFB1). A second objective was to examine correlations between bacterial abundance and performance measures. Eight lactating dairy cows stratified by milk yield and parity were randomly assigned to 4 treatments in a 4 × 4 Latin square design with 2 replicate squares, four 33-d periods, and a 5-d washout between periods. The treatments included (1) control (basal diet, no additive); (2) T (control + 63.4 µg/kg AFB1, oral dose); (3) CL (T + 200 g/head per day of sodium bentonite clay, top-dress); and (4) CL+SCFP [CL + 19 g/head per day Diamond V NutriTek (Diamond V Inc., Cedar Rapids, IA) + 16 g/head per day MetaShield (Diamond V Inc.), top-dress]. Cows were adapted to diets containing no AFB1 from d 1 to 25 (predosing period). From d 26 to 30 (dosing period), AFB1 was orally dosed and then withdrawn for d 31 to 33 (withdrawal period). During the predosing period, compared with the control, feeding CL and CL+SCFP increased the relative abundance of the most dominant phylum, Bacteroidetes (55.1 and 55.8 vs. 50.6%, respectively), and feeding CL+SCFP increased Prevotella abundance (43.3 and 43.6 vs. 40.0%, respectively). During the dosing period, feeding AFB1 did not affect the ruminal bacterial community, but the relative abundance of Fibrobacteraceae increased with CL+SCFP compared with T (1.45 vs. 0.97%); Fibrobacter abundance also tended to increase with CL+SCFP compared with T and control, respectively (1.45 vs. 0.97 and 1.05%, respectively). Feeding AFB1 with or without CL or CL+SCFP did not affect ruminal pH or concentrations of NH3-N, total volatile fatty acids, or individual volatile fatty acids. Milk yield and milk component yields were positively correlated with the relative abundance of unclassified Succinivibrionaceae, unclassified YS2, or Coprococcus. Feed efficiency was positively correlated (r ≥ 0.30) with the relative abundance of unclassified YS2, Coprococcus, or Treponema. Feeding aflatoxin at 63 µg/kg, a common contamination level on farms, did not affect the abundance of dominant bacteria or rumen fermentation. When aflatoxin was fed, CL+SCFP increased the abundance of Fibrobacter, a major fibrolytic bacteria genus. Milk yield and DMI were positively correlated with abundance of Succinivibrionaceae and Coprococcus. Feed efficiency was positively correlated with abundance of Coprococcus, Treponema, and YS2. Future studies should speciate culture and determine the functions of the bacteria to elucidate their roles in the rumen and potential contribution to increasing the performance of dairy cows.

Pathological effects of concurrent administration of aflatoxin B1 and fowl adenovirus-4 in broiler chicks.

The current study was designed to investigate pathological effects of fowl adenovirus in broilers exposed to aflatoxin B1. Fowl Adenovirus-4 (FAdV-4) infection is remerging in all types of poultry birds in Pakistan. Poultry feed contamination with mycotoxin (aflatoxin) is another important global issue. A total of 125-day old broiler birds were divided into six equal groups. Group A served as control. B and C groups were administered with aflatoxin B1 (AFB1) 100 and 200 µg/kg feed. Group D was infected with FAdV-4, while groups E and F administered with both AFB1 (100 & 200 µg/kg) along with FAdV-4. These birds were monitored for clinical signs and mortality. Feed intake, body weight (BW), relative organ weights and gross & histopathological lesions were recorded. The highest mortality was observed in group F (FAdV-4 + AFB1 200 µg/kg feed) and the lowest mortality was observed in group B (AFB1 100 µg/kg feed). Body weights of all the groups were significantly (p < 0.05) lower as compared with control group. Relative weight of liver and kidneys in groups E and F were significantly higher as compared with control. Grossly, liver was swollen, anemic with round margins in groups D, E and F. Kidneys were also swollen with whitish areas indicating dead tissue. Microscopically intranuclear inclusion bodies were observed in group D-F. The hepatic parenchyma was also indicating necrotic changes along with vacuolar degeneration. In renal parenchyma, acute tubular necrosis was observed in groups C, E and F. It was concluded that AFB1 intoxication lead to dose dependent changes in liver and kidneys. Severity of the changes was increased in interactive groups of AFB1 with FAdV-4. Therefore, feed should be regularly monitored for AFB1 levels and day old chicks for vertically transmitted FAdV-4 to prevent losses.

Effects of dietary adsorbent on milk aflatoxin M1 content and the health of lactating dairy cows exposed to long-term aflatoxin B1 challenge.

The objective of this study was to evaluate the effects of Solis Mos (Novus International Inc., St. Charles, MO) on milk aflatoxin M1 (AFM1) content, lactation performance, plasma biochemical parameters, and ruminal fermentation in dairy cows exposed to long-term aflatoxin B1 (AFB1) challenge. Forty dairy cows were grouped according to days in milk (33 ± 7 d; mean ± SD) and milk production (33.9 ± 3.1 kg) and randomly assigned to 1 of 4 treatments: control (no additive), 20 µg of AFB1/kg of diet dry matter (AF), addition of Solis Mos at 0.25% of diet dry matter (SM), and MIX (AF + SM). The experiment lasted 9 wk, including an adaptation period during the first week. Dry matter intake, milk yield, and milk composition were measured on d 6 and 7 of each week. Milk AFM1, plasma biochemical parameters, and ruminal fermentation variables were analyzed on the last days of wk 1 and 9. No differences were observed in dry matter intake, milk yield, percentages of milk protein, milk fat, and lactose, and somatic cell counts across the treatments. Addition of adsorbent in the AFB1-contaminated diet significantly reduced the milk AFM1 concentrations (0.19 vs. 0.13 µg/kg) and transfer rates (1.38 vs. 0.89%). Dairy cows fed an AFB1-contaminated diet had lower superoxide dismutase activity, total antioxidant capacity, glutathione peroxidase, and levels of IgG and IgA, and higher levels of malondialdehyde in the plasma. Inclusion of Solis Mos in the diet increased the plasma superoxide dismutase activity, total antioxidant capacity, and IgG levels, and decreased the malondialdehyde level. Neither AFB1 nor Solis Mos affected the plasma levels of glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, alkaline phosphatase, or IgM. Long-term inclusion of adsorbent Solis Mos in the diet did not affect lactation performance or liver function, but it reduced milk AFM1 concentrations and oxidative stress and improved the immunological condition and ruminal fermentation in lactating dairy cows exposed to long-term AFB1 challenge.

Effects of nanostructured zeolite and aflatoxin B1 in growth performance, immune parameters and pathological conditions of rainbow trout Oncorhynchus mykiss.

The reduction of Aflatoxin B1 (AF) in juvenile rainbow trout (Oncorhynchus mykiss) diet was analyzed after supplementing Nanostructured Zeolite (NZ) in a 56-day experiment. Two hundred and seventy juveniles with an average weight of 23 ± 3.7 g were placed in 6 different groups of C (control as a basal diet), NZ0.5 (basal diet + 0.5% NZ), NZ1 (basal diet + 1% NZ), AF5 (basal diet + 5 mg AFB1), AF5 NZ0.5 (basal diet + 5 mg AFB1 + 0.5% NZ), AF5 NZ1 (basal diet + 5 mg AFB1 + 1% NZ) with three replications and were fed four times a day based on their satiation. No significant differences were observed in terms of growth performance among the experimental groups (P > 0.05). However, hepatosomatic index in fish fed by AF5 NZ0.5 was reduced compared with NZ0.5 group (P < 0.05). The carcass moisture content showed a higher amount in treatment AF5 NZ0.5 compared to the control group (P < 0.05). There was a decrease in fat content in treatment AF5 compared to that of the control group (P < 0.05). Serum total protein, albumin and globulin levels in fish fed with aflatoxin were lower than in fish fed the diet without AF for all levels of NZ (P < 0.05); however, the interaction between AF and NZ was not significant (P > 0.05). Concentrations of C3, C4 and immunoglobulin M together with serum lysozyme activity showed no significant differences among all treatments (P > 0.05). No considerable histopathological lesions were observed in liver, kidney and spleen for all treatments. Based on the results, NZ showed some effects on physiological functions in juvenile rainbow trout fed by 0.5% dietary NZ which could improve performance in this species.

Impact of mycotoxins on the intestine: are mucus and microbiota new targets?

There is an increasing awareness of the deleterious effects attributed to mycotoxins during their fate within the gut, particularly for deoxynivalenol (DON), zearalenone (ZEN), ochratoxin A (OTA), fumonisin B1 (FB1), aflatoxin B1 (AFB1), and patulin (PAT). Evidence indicates that disruption of the epithelial barrier is well established. However, intestinal barrier function on its luminal side involves two other partners, mucus and microbiota, which have rarely been considered in the context of mycotoxin exposure. The current review aimed at providing a summary of DON, ZEN, OTA, FB1, AFB1, and PAT effects on intestinal barrier function, with special focus on mucus and microbiota. DON, ZEN, OTA, FB1, AFB1, and PAT are known to markedly affect epithelial cell integrity and functions. Regarding mucus, DON is the most documentated mycotoxin. In vivo, toxicological impact of DON generally has only been assessed through goblet cell number. Evaluation of the mycotoxins/mucus interplay considering other indicators such as composition, thickness, and penetrability of mucus, mucin O-glycosylation thus warrants further attention. With respect to microbiota, few short-term studies to date have been reported indicating deleterious effects. However, long-term exposure to mycotoxins may also produce significant changes in microbiota composition and metabolic activity, which requires further experimentation. In conclusion, mucus and microbiota are key targets for dietary mycotoxins although assessment of induced effects is preliminary. A significant research effort is now underway to determine the adverse consequences of mycotoxins on mucus and microbiota considered as individual but also as tightly connected gut players.

Polymorphisms in the precursor microRNAs and aflatoxin B1-related hepatocellular carcinoma.

The altered expression of some microRNAs (miRNAs) is observed in hepatocellular carcinoma (HCC); however, the genetic polymorphisms in the precursor miRNAs (pre-miRNAs) in aflatoxin B1 (AFB1)-related HCC have not yet been investigated. A hospital-based case-control study, including 1,706 HCC cases and 2,270 controls without any liver diseases or tumors, was conducted in a high AFB1 exposure area of China to assess the relationship between 48 polymorphisms in the pre-miRNAs and AFB1-related HCC risk and prognosis. Among 48 polymorphisms, only rs28599926 (in the miRNA 1268a) affected HCC risk. Compared with the homozygote of rs28599926C alleles (rs28599926-CC), the genotypes of rs28599926 T alleles (namely rs28599926-CT or -TT) increased HCC risk (odds ratio [OR]: 1.63 and 5.52, 95% confidence interval [CI]: 1.40-1.90 and 4.27-7.14, respectively). Significant interactive effects between risk genotypes and AFB1 exposure status were also observed in the joint effects analysis. This polymorphism was associated not only with larger tumor size, higher portal vein tumor risk, and tumor dedifferentiation, but also with higher AFB1 adducts levels and increasing the mutation risk of TP53 gene. Furthermore, rs28599926 modified the tumor recurrence-free survival (hazard ratio [HR]: 2.86, 95% CI: 2.36-3.43) and overall survival (HR: 2.12, 95% CI: 1.86-2.41) of cases. Additionally, one target of miR-1268a was show to be the ADAMTS4 mRNA and rs28599926 polymorphism might modify ADAMTS4 expression. These findings indicate that polymorphisms in the pre-miRNAs may be risk and prognostic biomarkers of AFB1-related HCC, and rs28599926 in miR-1268a is such a potential candidate. © 2015 Wiley Periodicals, Inc.

Intervention of Grape Seed Proanthocyanidin Extract on the Subchronic Immune Injury in Mice Induced by Aflatoxin B1.

The aim was to investigate the prevention of grape seed proanthocyanidin extract (GSPE) on the subchronic immune injury induced by aflatoxin B1 (AFB1) and the possible ameliorating effect of GSPE in mice. The subchronic AFB1-induced immune injury mice model was set up with the continuous administration of 100 µg/kg body weight (BW) AFB1 for six weeks by intragastric administration. Then, intervention with different doses (50 and 100 mg/kg BW) of GSPE was conducted on mice to analyze the changes of body weight, immune organ index, antioxidant capability of spleen, serum immunoglobulin content, and the expression levels of inflammatory cytokines. The prevention of GSPE on the immune injury induced by AFB1 was studied. The GSPE could relieve the AFB1-induced reduction of body weight gain and the atrophy of the immune organ. The malondialdehyde (MDA) level of the spleen in the AFB1 model group significantly increased, but levels of catalase (CAT), glutathione (GSH), glutathione peroxidase (GSH-P(X)), and superoxide dismutase (SOD) significantly decreased. The GSPE could significantly inhibit the oxidative stress injury of the spleen induced by AFB1. AFB1 exposure could not significantly change the contents of IgA, IgG, or IgM. AFB1 significantly improved the expression of interleukin 1ß (IL-1ß), IL-6, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ). Additionally, GSPE could decrease the expression of these four proinflammatory factors to different degrees and inhibit the inflammatory reaction of mice. The results suggest that GSPE alleviates AFB1-induced oxidative stress and significantly improves the immune injury of mice induced by AFB1.

Pathological changes in the immune organs of broiler chickens fed on corn naturally contaminated with aflatoxins B1 and B2.

The purpose of this study was to evaluate the underlying basis for aflatoxin-induced immunosuppression in the broiler chicken by detecting pathological lesions and apoptosis in thymus, bursa of Fabricius (BF) and spleen. COBB500™ male broiler chicks were randomly allocated to two groups. The control group was fed on a basal corn-based diet while the other group (the AFB group) was fed on a similar diet but the corn was naturally contaminated with aflatoxins B1 and B2. Histopathological examination revealed that in the AFB group there was more nuclear debris in the three immune organs and obvious congestion of red pulp in the spleen, when compared with the control group. Ultrastructural examination showed lesions in the lymphocytes and reticulocytes of the three immune organs, the mucosal epithelium of the BF and the plasmocytes of the spleen. Increased apoptotic cells and an impaired membrane system (including nuclear membrane, mitochondria and endoplasmic reticulum [ER]) could be observed in the three immune organs in birds of the AFB group. In the plasmocytes, dilated rough endoplasmic reticulum contained electron-dense matrix. By flow cytometry, the percentages of apoptosis were significantly higher (P < 0.01) in the three organs of the AFB group than those of the control group. These observations suggested that the lesions of the immune organs were related to the immunosuppression, and that the apoptosis might be initiated by the mitochondrial pathway and ER chaperone pathway.

Effects of aflatoxin b1 on T-cell subsets and mRNA expression of cytokines in the intestine of broilers.

This study was conducted to investigate the effects of aflatoxin B1 (AFB1) on T-cell subsets and mRNA expression of cytokines in the small intestine of broilers. One hundred and fifty-six one-day-old healthy Cobb broilers were randomly divided into control group (0 mg/kg AFB1) and AFB1 group (0.6 mg/kg AFB1) with three replicates per group and 26 birds per replicate for 21 days, respectively. At 7, 14, and 21 days of age, the duodenum, jejunum and ileum were sampled for analyzing T cell subsets (CD3+, CD3+CD4+ and CD3+CD8+) by flow cytometry as well as IL-2, IL-4, IL-6, IL-10, IL-17, IFN-γ and TNF-α mRNA expression by qRT-PCR. The percentages of T-cells in the intra-epithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) of duodenum, jejunum and ileum in the AFB1 group showed a decreased tendency in comparison to the control group. The mRNA expression of cytokines in the three intestinal segments in the AFB1 group presented a general decline compared with the control groups. Our data demonstrated that 0.6 mg/kg AFB1 in the broilers diet could reduce the percentages of T-cell subsets and the expression level of cytokine mRNA in the small intestine, implying that the immune function of the intestinal mucosa might be affected. The reduction of cytokines mRNA expression may be closely associated with the decreased proportions of T cells subsets induced by AFB1.

Molecular basis of aflatoxin-induced mutagenesis-role of the aflatoxin B1-formamidopyrimidine adduct.

Aflatoxin B1 (AFB1) is a known carcinogen associated with early-onset hepatocellular carcinoma (HCC) and is thought to contribute to over half a million new HCCs per year. Although some of the fundamental risk factors are established, the molecular basis of AFB1-induced mutagenesis in primate cells has not been rigorously investigated. To gain insights into genome instability that is produced as a result of replicating DNAs containing AFB1 adducts, site-specific mutagenesis assays were used to establish the mutagenic potential of the persistent ring-opened AFB1 adduct, AFB1-formamidopyrimidine (AFB1-FAPY). This lesion was highly mutagenic, yielding replication error frequencies of 97%, with the predominant base substitution being a G to T transversion. This transversion is consistent with previous mutational data derived from aflatoxin-associated HCCs. In vitro translesion synthesis assays demonstrated that polymerase (pol) ζ was the most likely candidate polymerase that is responsible for the G to T mutations induced by this adduct.

Association between aflatoxin B1 occupational airway exposure and risk of hepatocellular carcinoma: a case-control study.

The aim of this study was to determine the airway exposure of sugar and papermaking factory workers to aflatoxin B1 (AFB1) and to explore the potential association between AFB1 airway exposure and the risk of hepatocellular carcinoma (HCC) in a case-control study. Dust samples were collected from the sugarcane bagasse warehouse, and presser and paper production workshops. Blood samples were collected from 181 workshop employees and 203 controls who worked outside the workshop. AFB1 albumin adducts were detected using a double antibody sandwich enzyme-linked immunosorbent assay (ELISA). To explore the association between AFB1 airway exposure and the risk of HCC, the medical records of 68 HCC patients who worked in a sugar and papermaking factory between January 1994 and December 2013 were analyzed. A questionnaire was used to collect information from 150 healthy controls who worked for the same company and lived near the factory. AFB1 was detected in the dust samples, but could not be detected in any of the rice samples. An analysis of serum samples revealed serum AFB1 albumin adducts in 102 (56.35 %) of the study participants. However, in the control group, only 12 (5.9 %) individuals had detectable levels of AFB1 albumin adducts. Those with airway exposure to Aspergillus flavus-contaminated dust had an elevated risk of HCC compared to those without exposure (odds ratio, 5.24; 95 % confidence interval, 2.77-9.88; P = 0.00). The findings of this study indicate that occupational AFB1 airway exposure might be associated with the risk of AFB1-related HCC among the population that was used in this study. Intervention programs aimed at reducing exposure to inhalational AFB1 are needed urgently. Additional suitably designed, multicenter, prospective studies using large samples are needed to further confirm the results.

Etiological and molecular profile of hepatocellular cancer from India.

Hepatocellular carcinoma (HCC) cases are underreported in India. Our study was designed to investigate the etiological profile of HCC cases in India and compare with global incidence. The study included 348 HCC and 375 chronic liver disease cases without HCC as controls. Samples were screened for hepatitis B virus (HBV)/hepatitis C virus (HCV) infections using enzyme-linked immunosorbent assay and polymerase chain reaction (PCR). HBV-DNA and HCV-RNA genotyping was performed by PCR-restriction fragment length polymorphism. All cases were also assessed for other possible risk factors of HCC. Among HCC cases, 62.6% were positive for HBV, 26.7% for HCV and 3.2% had coinfection. Around 17% of HCC cases had aflatoxin-B1 exposure. HBV genotype D (odds ratio, OR = 1.76) and mixed genotypes (OR = 6.86) had higher risk of HCC development. The risk of HCC was twofold (OR = 2.26) in patients with high HBV-DNA levels. Moreover, our findings were unable to establish a clear differential effect of HCV genotype (OR = 1.48) and high viral load (OR = 1.21) on HCC development. In India, HBV is the major risk factors, whereas alcohol, smoking and diabetes are nonsignificantly associated. Asian countries such as Hong Kong and Taiwan also had high incidence of HBV-related HCC. Contrarily, countries from Europe and USA reported HCV as predominant cause of HCC. Further, aflatoxin could be a possible risk of HCC in the population. However, in comparison to the countries such as China and Taiwan (high Aflatoxin exposure), the aflatoxin level is relatively low in our patients. High HBV-DNA levels and HBV/D increased the risk of HCC. However, neither genotype nor virus loads of HCV affected prognosis of HCC patients in our study.

Occupational exposure to aflatoxin B1 in swine production and possible contamination sources.

Although the adverse health consequences of ingestion of food contaminated with aflatoxin B1 (AFB1) are known, relatively few studies are available on the adverse effects of exposure in occupational settings. Taking this into consideration, our study was developed aiming to elucidate the possible effects of occupational exposure to AFB1 in Portuguese swine production facilities using a specific biomarker to assess exposure to AFB1. In total, 28 workers participated in this study, providing blood samples, and a control group (n = 30) was composed of subjects without any type of agricultural activity. Fungal contamination was also studied by conventional methods through air, surfaces, and new and used floor coverage. Twenty-one workers (75%) showed detectable levels of AFB1 with values ranging from <1 ng/ml to 8.94 ng/ml and with a mean value of 1.91 ± 1.68 ng/ml. In the control group, the AFB1 values were all below 1 ng/ml. Twelve different Aspergillus species were identified. Aspergillus versicolor presented the highest airborne spore counts (3210 CFU/m3) and was also detected in higher values in surfaces (>300 CFU/cm2). Data indicate that exposure to AFB1 occurs in swine barns, and this site serves as a contamination source in an occupational setting.

Low Frequency of Aflatoxin Induced TP53 Gene Codon 249 Mutation in Hepatocellular Carcinoma from Egyptian Patients Living in the Nile Delta Region.

OBJECTIVE: Study the frequency of codon 7 (c.747 G>T, p. R249S) mutation associated with Aflatoxin B1 (AFB1) exposure in Egyptian patients with hepatocellular carcinoma (HCC). METHODS: We utilized restriction fragment polymorphism and direct sequencing to assess codon 7 mutations in 104 hepatocellular carcinomas. The expression of TP53 protein in the tumors were assessed in 44 tumors by a monoclonal rabbit antibody. RESULTS: We identified a single 1/104 (1%) with c.747 G>T, p. R249S variant. 28/44 (63.6%) tumors showed no or occasional (less than < 5%) nuclear staining; 9/44 (20.4%) showed mild to moderate (5-49%) and 7/44 (15.9%) showed strong ≥ 50% staining. CONCLUSION: We observed much lower frequency of TP53 gene than previously published results suggesting geographical alterations in AFB1 exposure in Egypt.