Evaluation of Toxicant-Associated Fatty Liver Disease and Liver Neoplastic Progress in Sprague-Dawley Rats Treated with Low Doses of Aflatoxin B1 Alone or in Combination with Extremely Low Frequency Electromagnetic Fields

The term toxicant-associated fatty liver disease (TAFLD) has been proposed to describe fatty liver diseases connected to toxicants other than alcohol. Aflatoxins are mycotoxins commonly found as contaminants in foods and feeds, which are known liver toxicants and potential candidates as potential causes of TAFLD. Aflatoxin B1 (AFB1) was administered at low doses to Sprague-Daw-ley (SD) rats, alone or in combination with S-50 Hz an extremely low frequency electromagnetic field (ELFEMF), to study the evolution of TAFLD, preneoplastic and neoplastic lesions of the liver and the potential enhancing effect of lifespan exposure to ELFEMF. Steatosis, inflammation and foci of different types were significantly increased in both aflatoxin-treated males and females, which is consistent with a pattern of TAFLD. A significant increase in adenomas, cystic dilation of biliary ducts, hepatocellular hyperplasia and hypertrophy and oval cell hyperplasia were also observed in treated females only. The administration of low doses of AFB1 caused TAFLD in SD rats, inducing liver lesions encompassing fatty infiltration, foci of different types and adenomas. Furthermore, the pattern of change observed in preneoplastic liver lesions often included liver steatosis and steato-hepatitis (TASH). ELFEMF did not result in any enhancing or toxic effect in the liver of SD rats

Aflatoxin B1 DNA-Adducts in Hepatocellular Carcinoma from a Low Exposure Area

Aflatoxin B1 (AFB1) is a class 1 carcinogen with an ascertained role in the development of hepatocellular carcinoma (HCC) in high exposure areas. Instead, this study aimed to assay whether chronic/intermittent, low-dose AFB1 consumption might occur in low-exposure geographical areas, ultimately accumulating in the liver and possibly contributing to liver cancer. AFB1-DNA adducts were assayed by immunostaining in liver tissues from three Italian series of twenty cirrhosis without HCC, 131 HCC, and 45 cholangiocarcinoma, and in an AFB1-induced HCC rat model. CD68, TP53 immunostaining, and TP53 RFLP analysis of R249S transversion were used to characterize cell popula-tions displaying AFB1-DNA adducts. Twenty-five HCCs displayed AFB1-adducts both in neoplastic hepatocytes and in cells infiltrating the tumor and non-tumor tissues. Nuclear immunostaining was observed in a few cases, while most cases showed cytoplasmic immunostaining, especially in CD68-positive tumor-infiltrating cells, suggestive for phagocytosis of dead hepatocytes. Similar patterns were observed in AFB1-induced rat HCC, though with higher intensity. Cholangiocarcinoma and cirrhosis without HCC did not displayAFB1-adducts, except for one case. Despite not providing a causal relationship with HCC, these findings still suggest paying attention to detection and control measures for aflatoxins to ensure food safety in low exposure areas

Co-carcinogenic effects of vitamin E in prostate

A large number of basic researches and observational studies suggested the cancer preventive activity of vitamin E, but large-scale human intervention trials have yielded disappointing results and actually showed a higher incidence of prostate cancer although the mechanisms underlying the increased risk remain largely unknown. Here we show through in vitro and in vivo studies that vitamin E produces a marked inductive effect on carcinogen-bioactivating enzymes and a pro-oxidant status promoting both DNA damage and cell transformation frequency. First, we found that vitamin E in the human prostate epithelial RWPE-1 cell line has the remarkable ability to upregulate the expression of various phase-I activating cytochrome P450 (CYP) enzymes, including activators of polycyclic aromatic hydrocarbons (PAHs), giving rise to supraphysiological levels of reactive oxygen species. Furthermore, our rat model confirmed that vitamin E in the prostate has a powerful booster effect on CYP enzymes associated with the generation of oxidative stress, thereby favoring lipid-derived electrophile spread that covalently modifies proteins. We show that vitamin E not only causes DNA damage but also promotes cell transformation frequency induced by the PAH-prototype benzo[a]pyrene. Our findings might explain why dietary supplementation with vitamin E increases the prostate cancer risk among healthy men

Disruption of redox homeostasis and carcinogen metabolizing enzymes changes by administration of vitamin E to rats.

Aims A large meta-analysis of randomized clinical trials has seriously questioned chemoprevention based on vitamins including Vitamin E (VE), and an increased risk for cancer among long-term users was actually seen. However, the mechanism underlying these findings still remain unknown. To clarify the mechanism, in an in vivo model we studied the putative disruption of redox homeostasis and the perturbation of carcinogen metabolizing enzymes determined by VE. Main methods Male Sprague-Dawley rats were treated ip with either 100 or 200 mg/kg b.w. daily for 7 or 14 consecutive days. Controls received vehicle only. Cytochrome P450 (CYP) content, CYP-reductase, CYP-linked monooxygenases, as well as phase-II and the antioxidant enzymes catalase and NAD(P)H:quinone reductase were investigated in both liver and kidney. Free radical species in tissue subcellular preparations were measured by electronic paramagnetic resonance (EPR) spectroscopy coupled to a radical probe technique. Key findings No substantial changes of hepatic xenobiotic metabolism enzymes were determined by VE. Conversely, a powerful booster effect of various renal phase-I carcinogen bioactivating enzymes at both dosages and observational times was recorded. While no relevant changes of post-oxidative phase-II reactions were found in the liver, a significant inactivating effect was caused by VE in renal tissues. Antioxidant enzymes were found mainly downregulated by the treatment. In the kidney, a marked free radical over-generation linked to CYP induction was observed. Significance This study proved that VE acts as a co-carcinogen and pro-oxidant agent. Such epigenetic mechanisms may contribute to explain the harmful outcomes observed in humans

Wild Italian Prunus spinosa L. Fruit exerts in vitro antimicrobial activity and protects against in vitro and in vivo oxidative stress

Polyphenol-rich foods could have a pivotal function in the prevention of oxidative stress-based pathologies and antibacterial action. The purpose of this study was to investigate the in vitro antimicrobial activity as well as the in vitro and In Vivo antioxidant capacities of wild Prunus spinosa L. fruit (PSF) from the southeast regions of Italy. The total phenolic content (TPC) was quantified, and the single polyphenols were analyzed by HPLC-DAD, showing high rutin and 4-hydroxybenzoic acid levels, followed by gallic and trans-sinapic acids. PSF extract demonstrated antimicrobial activity against some potentially pathogenic Gram-negative and Gram-positive bacteria. Besides, we investigated the cellular antioxidant activity (CAA) and the hemolysis inhibition of PSF extract on human erythrocytes, evidencing both a good antioxidant power and a marked hemolysis inhibition. Furthermore, an In Vivo experiment with oxidative stress-induced rats treated with a high-fat diet (HFD) and a low dose of streptozotocin (STZ) demonstrated that PSF has a dose-dependent antioxidant capacity both in liver and in brain. In conclusion, the wild Italian Prunus spinosa L. fruit could be considered a potentially useful material for both nutraceutical and food industries because of its antioxidant and antimicrobial effects

Effetti co-cancerogeni della vitamina E a livello prostatico

Numerosi studi sperimentali suggeriscono un ruolo chemiopreventivo della vitamina E (VE) nei confronti di numerose patologie tumorali incluso il cancro alla prostata (CA). Tuttavia, le evidenze epidemiologiche pi\uf9 recenti non confermano tale ipotesi, e lo studio clinico SELECT ha addirittura evidenziato un aumento dell\u2019incidenza di CA alla prostata in pazienti sani al momento dell\u2019arruolamento, ai quali era stata somministrata VE giornalmente alla dose di 400 UI/die. Essendo noto in letteratura come alcune isoforme del citocromo P450 (CYP) siano sovra espresse in lesioni prostatiche maligne, e che la VE, agisca come induttore del CYP in alcuni tessuti, abbiamo ipotizzato che l\u2019aumento dell\u2019incidenza di CA possa coinvolgere un meccanismo co-cancerogenico legato all\u2019induzione CYP. L\u2019esposizione a VE produce una marcata induzione del CYP in cellule epiteliali di prostata RWPE-1, incluse le isoforme responsabili dell\u2019attivazione degli Idrocarburi Policiclici Aromatici (IPA), accompagnata da un significativo aumento delle specie reattive dell\u2019ossigeno (ROS). Inoltre, il pathway pro-infiammatorio COX-2-dipendente risulta incrementato, caratteristica che si osserva in diverse forme tumorali incluso quelle che interessano la prostata. Il fenomeno \ue8 stato confermato nel modello animale; \ue8 stato osservato un aumento delle monoossigenasi e dell\u2019espressione genica di alcune isoforme CYP a livello prostatico unito a una maggiore concentrazione di ROS, in linea con marcatori di danno ossidativo a livello proteico e lipidico, nella prostata di ratto. L\u2019esposizione di cellule IMR90 a VE ha evidenziato un effetto genotossico riportando un\u2019aumentata frequenza dei micronuclei (MN). Il potenziale co-cancerogeno di VE \ue8 stato poi confermato dallo studio della trasformazione cellulare mediate l\u2019uso di cellule BALB/c 3T3. Cellule pre-incubate con VE e successivamente esposte a benzo[a]pirene mostrano un significativo incremento della frequenza di trasformazione rispetto a quello senza della vitamina. Il presente studio dimostra come la VE possa, in determinate condizioni, agire come co-cancerogeno tramite un meccanismo CYP-dipendente, causando danno al DNA e promovendo la trasformazione cellulare