Vulnerability of Polarised Intestinal Porcine Epithelial Cells to Mycotoxin Deoxynivalenol Depends on the Route of Application

BACKGROUND AND AIMS: Deoxynivalenol (DON) is a Fusarium derived mycotoxin, often occurring on cereals used for human and animal nutrition. The intestine, as prominent barrier for nutritional toxins, has to handle the mycotoxin from the mucosa protected luminal side (apical exposure), as well as already absorbed toxin, reaching the cells from basolateral side via the blood stream. In the present study, the impact of the direction of DON exposure on epithelial cell behaviour and intestinal barrier integrity was elucidated. METHODS: A non-transformed intestinal porcine epithelial cell line (IPEC-J2), cultured in membrane inserts, serving as a polarised in vitro model to determine the effects of deoxynivalenol (DON) on cellular viability and tight junction integrity. RESULTS: Application of DON in concentrations up to 4000 ng/mL for 24, 48 and 72 hours on the basolateral side of membrane cultured polarised IPEC-J2 cells resulted in a breakdown of the integrity of cell connections measured by transepithelial electrical resistance (TEER), as well as a reduced expression of the tight junction proteins ZO-1 and claudin 3. Epithelial cell number decreased and nuclei size was enlarged after 72 h incubation of 4000 ng/mL DON from basolateral. Although necrosis or caspase 3 mediated apoptosis was not detectable after basolateral DON application, cell cycle analysis revealed a significant increase in DNA fragmentation, decrease in G0/G1 phase and slight increase in G2/M phase after 72 hours incubation with DON 2000 ng/mL. CONCLUSIONS: Severity of impact of the mycotoxin deoxynivalenol on the intestinal epithelial barrier is dependent on route of application. The epithelium appears to be rather resistant towards apical (luminal) DON application whereas the same toxin dose from basolateral severely undermines barrier integrity

Effect of gender, pregnancy and exposure conditions on metabolism and distribution of zearalenone in rats

The mycotoxin zearalenone (ZEA) is produced by a variety of Fusarium fungi and contaminates numerous cereals, fruits and vegetables. Interacting with the oestrogen receptors, ZEA and reduced metabolites zearalenols (ZOLs) cause hormonal effects in animals, such as abnormalities in the development of the reproductive tract and mammary gland in female offspring. Limited information is available on the pharmacokinetics of ZEA and its metabolites, particularly in pregnant females, foetuses and newborns. Our study was conducted to characterise the tissue distribution and metabolism of ZEA in male and female rats in various physiological states (virgin female, pregnant female) and exposure conditions (subcutaneous versus oral exposure, single versus repeated exposure to 1 mg/kg ZEA). Respective placental and mammary transfer to foetuses and newborns was evaluated. In all states and exposure conditions, α-ZOL and the glucuronides of ZEA and α-ZOL were the predominant metabolites, mostly concentrated in the intestine, the liver and the urine. Toxins were very low or undetectable in most of the tissues 24 h after ZEA exposure, except in foetal livers. Absorption and intestinal glucuronidation of ZEA were higher in males than females. α-ZOL concentration was significantly higher in the intestine and liver of males and pregnant females, compared to virgin females. ZEA and all its metabolites easily crossed the placental barrier and transferred into the milk. ZEA was metabolised in the foetal and neonatal stages, glucuronides being the main form detected in all organs. Metabolite elimination was slower in foetal tissues than in maternal tissues. All toxin concentrations in the foetal and neonatal tissues strongly increased in cases of repeated maternal exposure. A better knowledge of the metabolism and transfer of ZEA in foetuses and newborns will help to evaluate the health risk that such endocrine disruptors represent in these stages. </jats:p

Co-exposure to low doses of the food contaminants deoxynivalenol and nivalenol has a synergistic inflammatory effect on intestinal explants

The global incidence of Fusarium head blight and attendant cereal grains multi-contamination by the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are increasing as a possible result of climate change and inadequate agricultural practices. At the molecular level, these mycotoxins bind to the ribosome, activate the mitogen-activated protein kinase and induce a local and systemic inflammation. DON is of public health concern owing to the narrow margin between exposure and tolerable daily intake. The intestinal inflammatory response to DON, NIV and their mixture was analyzed to determine thresholds for their intestinal pro-inflammatory effects and characterize the type and magnitude of their interaction. Fully differentiated three-dimensional porcine jejunal explants were exposed to increasing doses of DON and NIV alone or in combination; the expression levels of IL-1 alpha, IL-1 beta, IL-8, IL-17A and IL-22 were measured by RT-PCR. Doses as low as 0.16 mu M DON or 0.73 mu M NIV significantly increase the intestinal expression levels of the tested inflammation-related genes. These doses are lower than those previously reported for other intestinal toxicity endpoints. The combined pro-inflammatory activity of DON and NIV was synergistic for all the tested genes with combination index value range of 0.23-0.8. Our results indicate that (1) inflammation is a very sensitive endpoint for the intestinal toxicity of the trichothecenes and (2) co-exposure to DON and NIV has a greater inflammatory effect than induced by mycotoxins alone. This synergy should be taken into account considering the frequent co-occurrence of DON and NIV in the diet