Eric Gaultier

Impact of oral bisphenol A at reference doses on intestinal barrier function and sex differences after perinatal exposure in rats

Bisphenol A (BPA), a chemical estrogen widely used in the food-packaging industry and baby bottles, is recovered in human fluids (0.1–10 nM). Recent studies have reported that BPA is hormonally active at low doses, emphasizing the debate of a risk for human health. Estrogen receptors are expressed in the colon, and although the major route of BPA exposure is food, the effects on gut have received no attention. We first examined the endocrine disrupting potency of BPA on colonic paracellular permeability (CPP), experimental colitis, and visceral sensitivity in ovariectomized rats orally exposed to 5 mg/kg/d BPA (i.e., the no observed adverse effect level), 50 μg/kg/d BPA (i.e., tolerable daily intake), or lower doses. BPA dose-dependently decreased basal CPP, with a half-maximal inhibitory dose of 5.2 μg/kg/d, 10-fold below the tolerable daily intake. This correlated with an increase in epithelial tight junction sealing, also observed in Caco-2 cells exposed to 10 nM BPA. When ovariectomized rats were fed with BPA at the no observed adverse effect level, the severity of colitis was reduced, whereas the same dose increased pain sensitivity to colorectal stimuli. We then examined the impact of perinatal exposure to BPA on intestinal permeability and inflammatory response in the offspring. In female rats, but not in male rats, perinatal BPA evoked a decrease of CPP in adulthood, whereas the proinflammatory response of colonic mucosa was strengthened. This study first demonstrates that the xenoestrogen BPA at reference doses influences intestinal barrier function and gut nociception. Moreover, perinatal exposure promotes the development of severe inflammation in adult female offspring only.

Genotoxicity of Escherichia coli Nissle 1917 strain cannot be dissociated from its probiotic activity.

Oral administration of the probiotic bacterium Escherichia coli Nissle 1917 improves chronic inflammatory bowel diseases, but the molecular basis for this therapeutic efficacy is unknown. E. coli Nissle 1917 harbors a cluster of genes coding for the biosynthesis of hybrid nonribosomal peptide-polyketide(s). This biosynthetic pathway confers the ability for bacteria to induce DNA double strand breaks in eukaryotic cells. Here we reveal that inactivation of the clbA gene within this genomic island abrogated the ability for the strain to induce DNA damage and chromosomal abnormalities in non-transformed cultured rat intestinal epithelial cells but is required for the probiotic activity of E. coli Nissle 1917. Thus, evaluation of colitis severity induced in rodent fed with E. coli Nissle 1917 or an isogenic non-genotoxic mutant demonstrated the need for a functional biosynthetic pathway both in the amelioration of the disease and in the modulation of cytokine expression. Feeding rodents with a complemented strain for which genotoxicity was restored confirmed that this biosynthetic pathway contributes to the health benefits of the probiotic by modulating its immunomodulatory properties. Our data provide additional evidence for the benefit of this currently used probiotic in colitis but remind us that an efficient probiotic may also have side effects as any other medication.

Food intolerance at adulthood after perinatal exposure to the endocrine disruptor bisphenol A

The food contaminant bisphenol A (BPA) is pointed out as a risk factor in development of food allergy and food intolerance, two adverse food reactions increasing worldwide. We evaluated the consequences of perinatal exposure to low doses of BPA on immune‐specific response to the food antigen ovalbumin (OVA) at adulthood. Perinatal exposure to BPA (0.5, 5, or 50 μg/kg/d) from 15th day of gravidity to pups weaning resulted in an increase of anti‐OVA IgG titers at all BPA dosages in OVA‐tolerized rats, and at 5 μg/kg/d in OVA‐immunized rats compared to control rats treated with vehicle. In BPA‐treated and OVA‐tolerized rats, increased anti‐OVA IgG titers were associated with higher IFNγ secretion by the spleen. This result is in accordance with the increase of activated CD4+CD44high CD62Llow T lymphocytes observed in spleen of BPA‐exposed rats compared to controls. Finally, when BPA‐treated OVA‐tolerized rats were orally challenged with OVA, colonic inflammation occurred, with neutrophil infiltration, increased IFNγ, and decreased TGFβ. We show that perinatal exposure to BPA altered oral tolerance and immunization to dietary antigens (OVA). In summary, the naive immune system of neonate is vulnerable to low doses of BPA that trigger food intolerance later in life.—Menard, S., Guzylack‐Piriou, L., Leveque, M., Braniste, V., Lencina, C., Naturel, M., Moussa, L., Sekkal, S., Harkat, C., Gaultier, E., Theodorou, V., Houdeau, E., Food intolerance at adulthood after perinatal exposure to the endocrine disruptor bisphenol A. FASEB J. 28, 4893–4900 (2014). www.fasebj.org

Food-grade TiO 2 impairs intestinal and systemic immune homeostasis, initiates preneoplastic lesions and promotes aberrant crypt development in the rat colon

Food-grade titanium dioxide (TiO2) containing a nanoscale particle fraction (TiO2-NPs) is approved as a white pigment (E171 in Europe) in common foodstuffs, including confectionary. There are growing concerns that daily oral TiO2-NP intake is associated with an increased risk of chronic intestinal inflammation and carcinogenesis. In rats orally exposed for one week to E171 at human relevant levels, titanium was detected in the immune cells of Peyer’s patches (PP) as observed with the TiO2-NP model NM-105. Dendritic cell frequency increased in PP regardless of the TiO2 treatment, while regulatory T cells involved in dampening inflammatory responses decreased with E171 only, an effect still observed after 100 days of treatment. In all TiO2-treated rats, stimulation of immune cells isolated from PP showed a decrease in Thelper (Th)-1 IFN-γ secretion, while splenic Th1/Th17 inflammatory responses sharply increased. E171 or NM-105 for one week did not initiate intestinal inflammation, while a 100-day E171 treatment promoted colon microinflammation and initiated preneoplastic lesions while also fostering the growth of aberrant crypt foci in a chemically induced carcinogenesis model. These data should be considered for risk assessments of the susceptibility to Th17-driven autoimmune diseases and to colorectal cancer in humans exposed to TiO2 from dietary sources.

Dietary polyunsaturated fatty acids and heme iron induce oxidative stress biomarkers and a cancer promoting environment in the colon of rats

The end products of polyunsaturated fatty acid (PUFA) peroxidation, such as malondialdehyde (MDA), 4-hydroxynonenal (HNE), and isoprostanes (8-iso-PGF2α), are widely used as systemic lipid oxidation/oxidative stress biomarkers. However, some of these compounds have also a dietary origin. Thus, replacing dietary saturated fat by PUFAs would improve health but could also increase the formation of such compounds, especially in the case of a pro-oxidant/antioxidant imbalanced diet. Hence, the possible impact of dietary fatty acids and pro-oxidant compounds was studied in rats given diets allowing comparison of the effects of heme iron vs. ferric citrate and of ω-6- vs. ω-3-rich oil on the level of lipid peroxidation/oxidative stress biomarkers. Rats given a heme iron-rich diet without PUFA were used as controls. The results obtained have shown that MDA and the major urinary metabolite of HNE (the mercapturic acid of dihydroxynonane, DHN-MA) were highly dependent on the dietary factors tested, while 8-iso-PGF2α was modestly but significantly affected. Intestinal inflammation and tissue fatty acid composition were checked in parallel and could only explain the differences we observed to a limited extent. Thus, the differences in biomarkers were attributed to the formation of lipid oxidation compounds in food or during digestion, their intestinal absorption, and their excretion into urine. Moreover, fecal extracts from the rats fed the heme iron or fish oil diets were highly toxic for immortalized mouse colon cells. Such toxicity can eventually lead to promotion of colorectal carcinogenesis, supporting the epidemiological findings between red meat intake and colorectal cancer risk. Therefore, the analysis of these biomarkers of lipid peroxidation/oxidative stress in urine should be used with caution when dietary factors are not well controlled, while control of their possible dietary intake is needed also because of their pro-inflammatory, toxic, and even cocarcinogenic effects.

Perinatal Exposure to a Low Dose of Bisphenol A Impaired Systemic Cellular Immune Response and Predisposes Young Rats to Intestinal Parasitic Infection

Perinatal exposure to the food contaminant bisphenol A (BPA) in rats induces long lasting adverse effects on intestinal immune homeostasis. This study was aimed at examining the immune response to dietary antigens and the clearance of parasites in young rats at the end of perinatal exposure to a low dose of BPA. Female rats were fed with BPA [5 µg/kg of body weight/day] or vehicle from gestational day 15 to pup weaning. Juvenile female offspring (day (D)25) were used to analyze immune cell populations, humoral and cellular responses after oral tolerance or immunization protocol to ovalbumin (OVA), and susceptibility to infection by the intestinal nematode Nippostrongylus brasiliensis (N. brasiliensis). Anti-OVA IgG titers following either oral tolerance or immunization were not affected after BPA perinatal exposure, while a sharp decrease in OVA-induced IFNγ secretion occurred in spleen and mesenteric lymph nodes (MLN) of OVA-immunized rats. These results are consistent with a decreased number of helper T cells, regulatory T cells and dendritic cells in spleen and MLN of BPA-exposed rats. The lack of cellular response to antigens questioned the ability of BPA-exposed rats to clear intestinal infections. A 1.5-fold increase in N. brasiliensis living larvae was observed in the intestine of BPA-exposed rats compared to controls due to an inappropriate Th1/Th2 cytokine production in infected jejunal tissues. These results show that perinatal BPA exposure impairs cellular response to food antigens, and increases susceptibility to intestinal parasitic infection in the juveniles. This emphasized the maturing immune system during perinatal period highly sensitive to low dose exposure to BPA, altering innate and adaptative immune response capacities in early life.

Food-Grade TIO 2 Pigment Initiates Preneoplastic Lesions and Promotes Aberrant Crypt Development in the Rat Colon

Food-grade TIO2 pigment initiates preneoplastic lesions and promotes aberrant crypt development in the rat colon. Digestive Disease Week (DDW)

Characterization of Titanium Dioxide Nanoparticle Intestinal Absorption, in Vivo and Ex Vivo , in the Mouse

AGA DDW Mai 2017 Characterization of titanium dioxide nanoparticle intestinal absorption, in vivo and ex vivo, in the mouse. Christel Cartier, Eric Gaultier, Olivier Catrice, Quentin Panouillet, Sarah El Hamdi, Vassilia Théodorou, Eric Houdeau and Christine Coméra Toxalim (Research Centre in Food Toxicology), Université de Toulouse, INRA, ENVT, INPPurpan, UPS, Toulouse, France Background : Titanium dioxide (TiO2) nanoparticles are ingested on a daily basis by millions of people, especially in western countries, being largely used as additive in manufactured foods or pharmaceutical drugs. Its oral administration was shown to exacerbate colitis, during UC or Crohn Diseases, by activating the NRLP3 inflammasome in gut and increasing its overall distribution in the blood or the spleen (Lomer MC Br J Nutr 2004;92:947, Ruiz PA, Gut. 2016 Feb 4. pii: gutjnl-2015-310297). Methods : Our study investigated the intestinal absorptive route of the alimentary TiO2 (E171) , after a unique gavage in mice, characterizing the major sites and kinetic of its absorption and distribution in the intestine and blood. The pathways of TiO2 absorption were also characterized ex vivo, in anesthetized mouse using specific inhibitors injected with the particles in ligatured loops of the jejunum. The TiO2 particles were detected using confocal microscopy and laser light reflection which uniquely permit to look at extended tissue area. Results : The TiO2 particles from 100 nm to 1-2 micrometers showed a major absorption in the jejunum in both the villi and Peyer Patches and much lower uptake in ileon and colon. In villi the TiO2 absorption rose until 4 hours after feeding and returned to control levels at 8 h while Peyer patches contents remained low at 4h but are significantly increased at 8 h. TiO2 particles were also 4 time increased in the blood at 4 and 8 h, compared to controls, showing similar kinetics of accumulations as previously reported in human (Pele, L. C. et al. Part Fibre Toxicol, 2015 12, 26). In ex vivo experiments the absorption of TiO2 in ligatured loops of jejunum were found to be rapid, clearly visible after 15 or 30 minutes of incubation and is inhibited by 66 % in the presence of 100 mM of TAP (4,5,6-Triaminopyrimidine sulfate) a tight junction blocker suggesting a major absorption via a paracellular pathways across epithelial tight junctions. By contrast, the intestinal uptake of TiO2 was not modified in the presence of either 100 mM 5-(N-Ethyl-N-isopropyl) amiloride inhibiting pinocytosis, 30 μM pitstop 2 which blocks clathrin dependent endocytosis or17 μM methyl beta-cyclodextrin affecting raft-mediated endocytosis, showing little or no contribution of endocytosis in the

Mo1733 Perinatal Exposure to Low Dose of Bisphenol a Alters Immune Cell Differentiation At Systemic and Intestinal Level in Young Offspring Rats

detected in colon tissue was significantly lower in both EBI2 and CH25H knockout mice as compared to wildtype controls (p < 0.01 and p < 0.05). Conclusion: The development of the intestinal lymphoid tissue and the intensity of inflammation in chronic DSS colitis seem to depend on an intact EBI2-7alpha,25-OHC system. These findings may establish EBI2-mediated cell migration as an important step in IBD pathogenesis and development of the gut immune system.

Mo1659 Perinatal Exposure to Low Doses of the Food Endocrine Disruptor Bisphenol A Impairs Oral Tolerance and Sensitization in Offspring Rats at Adulthood

Background: The food contaminant Bisphenol A (BPA) is the building plastic monomer widely used in food packaging and epoxy resins lining metal cans. BPA is a xenoestrogen known to disrupt endocrine function, liver metabolism and intestinal barrier function. We have previously shown that BPA exposure in utero and through lactation at the No Observed Adverse Effect Level (NOAEL) (5mg/kg/j) decreased colonic paracellular permeability and enhanced the TNBS-induced colitis severity in adult female offspring. Herein we aimed to address the consequences of perinatal exposure to 1000 time lower than NOAEL dose of BPA (5μg/kg/day) on the upper intestinal immune homeostasis at adulthood. Material and methods: Gravid and breast feeding rats were treated per os from the 15th day of gravidity to pups weaning (D21) with or without BPA [5μg/kg/d]. Paracellular (4kDa dextran-FITC) and transcellular (Horse Radish Peroxidase) jejunal permeability were addressed by Ussing chamber on female adult offspring aged of 45 days. In parallel, effects of BPA perinatal exposure on oral tolerance and systemic immunisation to ovalbumin (OVA) in adult offspring were tested. Anti-OVA IgG titers were measured by ELISA as well as IFNγ secretion after In Vitro stimulation of either spleen ormesenteric lymph nodes cells culture.Results: Perinatal treatment with BPA induced a decrease of jejunal transcellular permeability compared to controls (0.03±0.0045x10-7 vs 0.09±0.02 x10-7 cm/s; p<0.05) but did not affect jejunal paracellular permeability. Furthermore, BPA perinatally treated adult rats exhibited higher anti-OVA IgG titers following either an oral tolerance protocol (162±88.7x103 compared to 6.2±1.9 x103 in controls; p<0.03) or a sensitization with OVA (783±127x103 compared to 433±100 x103 in controls; p<0.03). Enhanced humoral response in perinatally BPA treated adult rats was associated with a higher production of IFNγ by spleen in sensitized rats (628.2±392 compared to 114.9±72 pg/ml in controls) and by mesenteric lymph nodes in tolerized rats (707±325 compared to 54.6±43 pg/ml in controls). Conclusion: Perinatal exposure to low doses of BPA decreased jejunal transcellular permeability and impaired oral tolerance and sensitization to dietary antigen protein in adult offsprings. These results suggest that the perinatal period is a critical window for BPA exposure that may trigger food intolerance in later life.