Immunohistochemical evidence for myofibroblast-like cells associated with liver injury induced by aflatoxin B1 in rainbow trout (Oncorhynchus mykiss)

Curcumin Alleviates Aflatoxin B1-Induced Liver Pyroptosis and Fibrosis by Regulating the JAK2/NLRP3 Signaling Pathway in Ducks

Aflatoxin B₁ (AFB₁) is a serious pollutant in feed and food which causes liver inflammation, fibrosis, and even cirrhosis. The Janus kinase 2 (JAK2)/signal transducers and activators of the transcription 3 (STAT3) signaling pathway is widely involved in inflammatory response and promotes the activation of nod-like receptor protein 3 (NLRP3) inflammasome, thus leading to pyroptosis and fibrosis. Curcumin is a natural compound with anti-inflammatory and anti-cancer properties. However, whether AFB₁ exposure leads to the activation of the JAK2/NLRP3 signaling pathway in the liver and whether curcumin can regulate this pathway to influence pyroptosis and fibrosis in the liver remains unclear. In order to clarify these problems, we first treated ducklings with 0, 30, or 60 µg/kg AFB₁ for 21 days. We found that AFB₁ exposure caused growth inhibition, liver structural and functional damage, and activated JAK2/NLRP3-mediated liver pyroptosis and fibrosis in ducks. Secondly, ducklings were divided into a control group, 60 µg/kg AFB₁ group, and 60 µg/kg AFB₁ + 500 mg/kg curcumin group. We found that curcumin significantly inhibited the activation of the JAK2/STAT3 pathway and NLRP3 inflammasome, as well as the occurrence of pyroptosis and fibrosis in AFB₁-exposed duck livers. These results suggested that curcumin alleviated AFB₁-induced liver pyroptosis and fibrosis by regulating the JAK2/NLRP3 signaling pathway in ducks. Curcumin is a potential agent for preventing and treating liver toxicity of AFB₁.

A continuous myofibroblast precursor cell line from the tail muscle of Australasian snapper (Chrysophrys auratus) that responds to transforming growth factor beta and fibroblast growth factor

Chrysophrys auratus (Australasian snapper) is one of the largest and most valuable finfish from capture fisheries in New Zealand, yet no cell lines from this species are reported in the scientific literature. Here, we describe a muscle-derived cell line initiated from the tail of a juvenile snapper which has been designated CAtmus1PFR (Chrysophrys auratus, tail muscle, Plant & Food Research). The cell line has been passaged over 100 times in 3 years and is considered immortal. Cells are reliant on serum supplementation for proliferation and exhibit a broad thermal profile comparable to the eurythermic nature of C. auratus in vivo. The impact of exogenous growth factors, including insulin-like growth factors I and II (IGF-I and IGF-II), basic fibroblast growth factor (bFGF), and transforming growth factor beta (TGFβ), on cell morphology and proliferation was investigated. Insulin-like growth factors acted as mitogens and had minimal effect on cell morphology. TGFβ exposure resulted in CAtmus1PFR exhibiting a myofibroblast morphology becoming enlarged with actin bundling. This differentiation was confirmed through the expression of smooth muscle actin (sma), an increase in type 1 collagen (col1a) expression, and a loss of motility. Expression of col1a and sma was decreased when cells were exposed to bFGF, and no actin bundling was observed. These data indicate that CAtmus1PFR may be myofibroblastic precursor cells descending from mesenchymal progenitor cells present in the tail muscle myosepta.

Aflatoxin B1 exposure and liver cirrhosis in Guatemala: a case-control study

Objective

In Guatemala, cirrhosis is among the 10 leading causes of death, and mortality rates have increased lately. The reasons for this heavy burden of disease are not clear as the prevalence of prominent risk factors, such as hepatitis B virus, hepatitis C virus and heavy alcohol consumption, appears to be low. Aflatoxin B₁ (AFB₁) exposure, however, appears to be high, and thus could be associated with the high burden of cirrhosis. Whether AFB₁ increases the risk of cirrhosis in the absence of viral infection, however, is not clear.

Design

Cirrhosis cases (n=100) from two major referral hospitals in Guatemala City were compared with controls (n=200) from a cross-sectional study. Logistic regression was used to estimate the ORs and 95% CIs of cirrhosis and quintiles of AFB₁ in crude and adjusted models. A sex-stratified analysis was also conducted.

Results

The median AFB₁ level was significantly higher among the cases (11.4 pg/mg) than controls (5.11 pg/mg). In logistic regression analyses, higher levels of AFB₁ was associated with cirrhosis (quintile 5 vs quintile 1, OR: 11.55; 95% CI 4.05 to 32.89). No attenuation was observed with adjustment by sex, ethnicity, hepatitis B virus status, and heavy alcohol consumption. A significantly increasing trend in association was observed in both models (p trend <0.01). Additionally, the cirrhosis–AFB₁ association was more prominent among men.

Conclusions

The current study found a significant positive association between AFB₁ exposure and cirrhosis. Mitigation of AFB₁ exposure and a better understanding of additional risk factors may be important to reduce the burden of cirrhosis in Guatemala.

Melaleuca alternifolia essential oil abrogates hepatic oxidative damage in silver catfish (Rhamdia quelen) fed with an aflatoxin-contaminated diet

Mycotoxins are secondary metabolites produced by varieties of fungi that contaminate food and feed resources and are capable of inducing a wide range of toxicity. This problem is extensively aggravated due to the increasing replacement of fish meal by plant-derived proteins. Among the mycotoxins, aflatoxins have received a great deal of attention owing to their great prevalence in plant feedstuffs and to the detrimental effects on animals. The objective of this study was to evaluate whether dietary supplementation with tea tree (Melaleuca alternifolia) oil (TTO) would avoid or minimize the negative impacts on silver catfish (Rhamdia quelen) fed with aflatoxins-contaminated diets. Four treatments were tested: control (fish fed with a control diet); AFB (fish fed with a mycotoxin-contaminated diet - 1893 μg kg^-1 of AFB₁ and 52.2 μg kg^-1 AFB₂); TTO (fish fed with a control diet + 1 mL kg^-1 of TTO), and TTO + AFB (fish fed with a mycotoxin contaminated diet - 2324 μg kg^-1 of AFB₁ and 43.5 μg kg^-1 AFB₂ + 1 mL kg^-1 of TTO). Diets were tested in three replications and analyzed at days 5 and 10 of dietary intake. Significantly reduced antioxidant enzymes (SOD, GPx, and GST) and increased lipid peroxidation (LOOH) and protein carbonyl (PC) content in plasma and liver, with 16.6% mortality occurrence, were observed in the group fed aflatoxin-contaminated diet. Furthermore, aflatoxins also significantly increased plasmatic and hepatic ROS levels and decreased hepatic antioxidant capacity against peroxyl radical (ACAP) levels. Plasma cortisol levels were not altered by aflatoxicosis, but the intoxication induced hepatose. Notwithstanding, addition of TTO to the groups receiving aflatoxins showed a protective effect, avoiding the increase of ROS, LOOH, and PC levels in plasma and liver. Moreover, TTO treatment ameliorated the aflatoxin-associated liver damage. Thus, TTO supplementation at concentration of 1 mL kg^-1 in feed may be used in fish to increase antioxidant status and reduce the negative effects caused by aflatoxins toxicity.

Occurrence and Levels of Aflatoxins in Fish Feeds and Their Potential Effects on Fish in Nyeri, Kenya

Aflatoxins are fungal metabolites that contaminate foods and feeds, causing adverse health effects in humans and animals. This study determined the occurrence of aflatoxins in fish feeds and their potential effects on fish. Eighty-one fish feeds were sampled from 70 farms and 8 feed manufacturing plants in Nyeri, Kenya for aflatoxin analysis using competitive enzyme-linked immunosorbent assay. Fish were sampled from 12 farms for gross and microscopic pathological examination. Eighty-four percent of feeds sampled tested positive for aflatoxins, ranging from 1.8 to 39.7 µg/kg with a mean of 7.0 ± 8.3 µg/kg and the median of 3.6 µg/kg. Fifteen feeds (18.5%) had aflatoxins above the maximum allowable level in Kenya of 10 µg/kg. Homemade and tilapia feeds had significantly higher aflatoxin levels than commercial and trout feeds. Feeds containing maize bran and fish meal had significantly higher aflatoxin levels than those without these ingredients. Five trout farms (41.7%) had fish with swollen abdomens, and enlarged livers with white or yellow nodules, which microscopically had large dark basophilic hepatic cells with hyperchromatic nuclei in irregular cords. In conclusion, aflatoxin contamination of fish feeds is prevalent in Nyeri, and may be the cause of adverse health effects in fish in this region.

Microcystin-LR increases genotoxicity induced by aflatoxin B1 through oxidative stress and DNA base excision repair genes in human hepatic cell lines

Aflatoxin B1 (AFB1) and microcystin-LR (MC-LR) simultaneously exist in polluted food and water in humid and warm areas, and each has been reported to be genotoxic to liver and associated with hepatocellular carcinoma (HCC). However, the genotoxic effects of the two biotoxins in combination and potential mechanism remain unknown. We treated the human hepatic cell line HL7702 with AFB1 and MC-LR together at different ratios, examined their genotoxic effects using micronuclei and comet assays, and evaluated the possible mechanism by measuring oxidative stress markers and DNA base excision repair (BER) genes. Our data show that co-exposure to AFB1 and MC-LR significantly increased DNA damage compared with AFB1 or MC-LR alone as measured by the levels of both micronuclei and tail DNA. Meanwhile, AFB1 and MC-LR co-exposure showed biphasic effects on ROS production, and a gradual trend towards increased Glutathione (GSH) levels and activity of Catalase (CAT) and Superoxide Dismutase (SOD). Furthermore, MC-LR, with or without AFB1, significantly down-regulated the expression of the base excision repair (BER) genes 8-oxoguanine glycosylase-1 (OGG1) and X-ray repair cross complementing group 1 (XRCC1). AFB1 and MC-LR in combination upregulated the expression of the BER gene apurinic/apyrimidinic endonuclease 1 (APE1), whereas either agent alone had no effect. In conclusion, our studies show that MC-LR exacerbates AFB1-induced genotoxicity and we report for the first time that this occurs through effects on oxidative stress and the deregulation of DNA base excision repair genes.

Aflatoxin B1 exposure increases the risk of cirrhosis and hepatocellular carcinoma in chronic hepatitis B virus carriers

The relation between aflatoxin B1 (AFB1 ) and cirrhosis in chronic carriers of hepatitis B virus (HBV) remains inconclusive. This case-control study nested in a large community-based cohort aimed to assess the effect of AFB1 exposure on cirrhosis and HCC in chronic HBV carriers. Serum AFB1 -albumin adduct levels at study entry were measured in 232 cirrhosis cases, 262 HCC cases and 577 controls. Multivariate-adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were estimated using logistic regression. Among all chronic HBV carriers, the time intervals between study entry and diagnosis of HCC, cirrhosis, cirrhotic HCC, and non-cirrhotic HCC were all significantly (p < 0.0001) shorter in participants with high serum levels of AFB1 -albumin adducts than those with low/undetectable levels. There were significant dose-response relations with serum AFB1 -albumin adduct level at study entry for cirrhosis (p-trend = 0.0001) and cirrhotic HCC (p-trend < 0.0001) newly diagnosed within 9 years after entry as well as non-cirrhotic HCC (p-trend = 0.021) newly diagnosed within 4 years after entry. The aORs (95% CIs) for high versus undetectable serum AFB1 -albumin adduct levels were 2.45 (1.51-3.98) for cirrhosis (p = 0.0003), 5.47 (2.20-13.63) for cirrhotic HCC (p = 0.0003), and 5.39 (1.11-26.18) for non-cirrhotic (p = 0.0368) HCC, respectively. There remained a significant dose-response relation between serum AFB1 -albumin adduct level and HCC risk (p-trend = 0.0291) in cirrhosis patients, showing an aOR (95% CI) of 3.04 (1.11-8.30) for high versus undetectable serum levels (p = 0.0299). It is concluded that AFB1 exposure may increase the risk of cirrhosis and HCC in a dose-response manner among chronic HBV carriers.

Mycotoxigenic fungi and natural co-occurrence of mycotoxins in rainbow trout (Oncorhynchus mykiss) feeds

Samples of rainbow trout feed were analyzed with the aim to determine the mycobiota composition and the co-occurrence of mycotoxins. A total of 28 samples of finished rainbow trout feed from hatcheries in the provinces of Río Negro and Neuquén, Argentina, were studied. Fungal counts were obtained on three culture media in the ranges of <10 to 4.2 × 10⁴ CFU/g on Dichloran Rose Bengal Chloramphenicol Agar (DRBC), <10 to 5.1 × 10⁴ CFU/g on Dichloran Chloramphenicol Peptone Agar (DCPA) and <10 to 3.6 × 10⁴ CFU/g on Dichloran 18% Glycerol Agar (DG18). The most frequent mycotoxigenic fungi were Eurotium (frequency (Fr) 25.0%), followed by Penicillium (Fr 21.4%) and Aspergillus (Fr 3.6%). The most prevalent mycotoxigenic species were E. repens (Fr 21.4%) and E. rubrum (Fr 14.3%). All samples were contaminated with mycotoxins: 64% samples were contaminated with T-2 toxin (median 70.08 ppb), 50% samples with zearalenone (median 87.97 ppb) and aflatoxins (median 2.82 ppb), 25% with ochratoxin A (median 5.26 ppb) and 3.57% samples with deoxynivalenol (median 230 ppb). Eight samples had a fumonisins contamination level below the limit of detection. Co-occurrence of six mycotoxins was determined in 7% of the samples.

Histopathological aspects of liver under variable food restriction: has the intense one-week food restriction a protective effect on non-alcoholic-fatty-liver-disease (NAFLD) development?

Non-alcoholic-fatty-liver-disease (NAFLD) is a clinicopathologic entity characterized by a variety of hepatic injury patterns without significant alcohol use. It has a close association with obesity, so treatment includes weight loss, control of insulin sensitivity, interventions directed at inflammation and fibrosis. There is a certain relationship between the grade and duration of food restriction and hepatic function. The objective of this work was to describe the relationship between biochemistry, autoantibodies, insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 3 (IGFBP-3), and liver morphology in experimental rabbit groups with food restriction as compared to controls with ad libitum food (ADL) income. The experiment was performed on a total of 24 rabbits of a weaning age of 25-81 days. The first group (R1) was restricted between 32 and 39 days of age to 50 g of food per rabbit a day. The second group (R2) was also restricted between 32 and 39 days, but the rabbits received 65 g of food per rabbit a day. At the end of the experiment, the blood and liver samples were collected at necropsy. NAFLD has developed in all three groups. There was any autoantibody positivity in all three groups. IGF-I is moderately higher in R1 and R2 group, as compared to the control group (P > 0.05). IGFBP-3 is without statistical significance in all three groups. Alkaline phosphatase (ALP) is the only liver biochemical parameter that has significantly increased following food restriction (P > 0.039). Single one-week restriction has any protective effect on NAFLD development.