Cherryl Harkat

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

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.

Multispecies probiotic protects gut barrier function in experimental models

AIMnTo investigate the effect of the probiotic combination Lactibiane Tolerance(®) (LT) on epithelial barrier function in vitro and in vivo.nnnMETHODSnThe effect of the multispecies probiotic LT was assessed on several models of epithelial barrier function both in vitro (in basal and inflammatory conditions) and in vivo [visceral hypersensitivity induced by chronic stress or by colonic perfusion of a fecal supernatant (FSN) from patients with irritable bowel syndrome (IBS)]. In vitro, we measured the permeability of confluent T84 cell monolayers incubated with or without LT by evaluating the paracellular flux of macromolecules, in basal conditions and after stimulation with lipopolysaccharide (LPS) or with conditioned medium of colonic biopsies from IBS patients (IBS-CM). In vivo, male C57/Bl6 mice received orally NaCl or LT for 15 d and were submitted to water avoidance stress (WAS) before evaluating visceral sensitivity by measuring the myoelectrical activity of the abdominal muscle and the paracellular permeability with (51)Cr-EDTA. Permeability and sensitivity were also measured after colonic instillation of FSN. Tight-junctions were assessed by immunoblotting and TLR-4 expression was evaluated by immunohistochemistrynnnRESULTSnIncubation of T84 cell monolayers with LT in basal conditions had no significant effect on permeability (P > 0.05 vs culture medium). By contrast, addition of LT bacterial bodies (LT) completely prevented the LPS-induced increase in paracellular permeability (P < 0.01 vs LPS 10 ng/mL (LPS 10); P < 0.01 vs LPS 100 ng/mL (LPS 100), P > 0.05 vs culture medium). The effect was dose dependent as addition of 10(9) LT bacterial bodies induced a stronger decrease in absorbance than 10(6) LT (10(9) LT + LPS 10: -20.1% ± 13.4, P < 0.01 vs LPS 10; 10(6) LT + LPS 10: -11.6% ± 6.2, P < 0.01 vs LPS 10; 10(9) LT + LPS 100: -14.4% ± 5.5, P < 0.01 vs LPS 100; 10(6) LT + LPS 100: -11.6% ± 7.3, P < 0.05 vs LPS 100). Moreover, the increase in paracellular permeability induced by culturing T84 cells with conditioned medium of colonic biopsies from IBS patients (IBS-CM) was completely inhibited in the presence of 10(9) LT (P < 0.01 vs IBS-CM). LT also significantly prevented the epithelial disruption induced by intracolonic infusion of fecal supernatant from IBS patients (P < 0.01 vs IBS FSN) or water avoidance stress P < 0.01 vs WAS) in C57/Bl6 mice and increased the expression of occludin in vitro and in vivo, as assessed by immnunoblotting. The WAS-induced effect on visceral sensitivity was prevented by LT treatment since values obtained for all steps of colorectal distension were significantly (P < 0.01) different from the WAS group. Finally, LT down-regulated the response mediated through TLR-4 in vitro (decrease in tumor necrosis factor α secretion in response to LPS: -65.8% for 10(9) LT and -52.5% for 10(6) LT, P < 0.01 vs LPS) and in vivo (inhibition of WAS induced an increase in TLR-4 expression in the LT treated mice colon, P < 0.01 vs WAS).nnnCONCLUSIONnThe probiotic LT mix prevented the disruption to the epithelial barrier induced by LPS, stress or colonic soluble factors from IBS patients and prevented visceral hypersensitivity.

Bifidobacterium longum and Lactobacillus helveticus Synergistically Suppress Stress-related Visceral Hypersensitivity Through Hypothalamic-Pituitary-Adrenal Axis Modulation

Background/Aims Visceral pain and hypothalamic-pituitary-adrenal axis (HPA) dysregulation is a common characteristic in irritable bowel syndrome (IBS) patients. Previously, we reported that a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) prevents chronic stress-mediated brain function abnormalities by attenuating the HPA axis response. Here, we compared the effect between different probiotic treatments on the perception of visceral pain during colorectal distension (CRD) following a chronic stress and the consequences to the activity of the HPA axis. Methods After a 2-week treatment with a combined probiotic formulation, or L. helveticus or B. longum alone in stressed mice, the visceral pain in response to CRD was recorded. The expression of glucocorticoid receptors was determined in the different brain areas involved in the stress response (hypothalamus, hippocampus, and prefrontal cortex). The plasma levels of stress hormones were also measured. Results A pretreatment using the combination of probiotic formulation significantly reduces the chronic stress-induced visceral hypersensitivity respectively at 0.06, 0.08, and 0.10 mL CRD volume. However, a single probiotic (B. longum or L. helveticus) administration is less effective in reducing visceral pain in stressed mice. Moreover, the expression of the glucocorticoid receptor mRNA was consistently up-regulated in several brain areas after pretreatment with a combined probiotic, which correlated with the normalization of stress response compared to the inconsistent effects of a single probiotic. Conclusion The combination of L. helveticus and B. longum is more effective in regulating glucocorticoid negative feedback on the HPA axis than probiotic alone and subsequently in treating stress-induced visceral pain.

Evaluation of reticulated gelatin-hibiscus-propolis against intestinal commensal species commonly associated with urinary tract infections

AIMnReticulated gelatin (RG), hibiscus and propolis (RGHP) is a medical device that can reduce the bacterial adherence to epithelial cultured cells and invasion by enteropathogens, thus gathering relevant properties to decrease the risk of urinary tract infections (UTIs). We aimed at evaluating in Wistar rats the efficacy of RGHP, RG and vehicle against intestinal commensals commonly involved in UTIs.nnnMETHODSnAnimals received orally (with supplemental Na2CO3): RGHP 1540 mg/day/rat; RG 500 mg/day/rat or vehicle.nnnRESULTSnRGHP significantly reduced fecal Escherichia coli and Enterococcus spp. levels without affecting other targeted Enterobacteriaceae. The antagonistic property of RGHP was confirmed in streptomycin-pretreated rats highly colonized with a human commensal E. coli strain with uropathogenic potential.nnnCONCLUSIONnRGHP may decrease the risk of UTIs by reducing colonization by opportunistic uropathogens.

Mo1302 In vivo Evaluation of Properties of a New Medical Device Against Intestinal Commensals With Uropathogenic Potential

number: 2439405. Title: In vivo evaluation of properties of a new medical device against intestinal commensals with uropathogenic potential Maïwenn Olier, Soraya Sekkal, Cherryl Harkat, Hélène Eutamène, Vassilia Theodorou, Lionel Buenouf085. UMR 1331 Toxalim, INRA/INPT/UPS, Neuro-Gastroenterology and Nutrition Group, Toulouse, France. uf085 Deceased Background: Based on protecting intestinal mucosa properties, a cross-linked protein compound, is a new medical device for the control and prevention of urinary tract infections. Considering that intestinal microbiota is a common immediate source of uropathogens, we evaluated the antagonistic activity of this product to limit the intestinal commensal bacterial communities with uropathogenic potential in feces of treated rats, decreasing their contact with the intestinal mucosa. Methods: Female Wistar rats were orally fed for 4 days either with the product (7500 mg kg , day, p.o) or vehicle (water plus Na2CO3, p.o). E. coli population and other Enterobacteriaceae such as Klebsiella spp., Enterobacter ssp., Serratia ssp., Citrobacter ssp. (named collectively KESC), Enterococcus ssp. or Proteeae ssp. were enumerated from feces collected throughout the course of the experiment by using selective chromogenic agar plates. Monitoring of fecal E. coli levels was additionally performed in streptomycin-pretreated rats highly colonized with a streptomycin-resistant human commensal O1:K1 E. coli strain sharing some common genetic traits of archetypal uropathogenic E. coli strains. Results: The treatment with the product resulted in a significant reduction of fecal endogenous E. coli (2.89+/-0.61 vs. 4.04+/-0.09 Log10 CFU/g feces, p<0.05) and Enterococcus spp. (3.77+/-0.29 vs. 5.24+/-0.12 Log10 CFU/g feces, p<0.01) levels without affecting other detected fecal opportunistic uropathogens. Antagonistic property of the product was additionally confirmed in feces of rats highly colonized with the O1:K1 E. coli strain (5.09+/-0.25 vs. 6.56+/-0.33 Log10 CFU/g feces, p<0.001). Conclusion: A cross linked protein product through its ability to reduce the risk of urinary tract infections by altering intestinal niche occupied by opportunistic uropathogens such as E. coli or Enterococcus spp may be a promising candidate in the management of urinary infections.

Sa1418 Targeted Epithelial Disruption Impacts Colonic Mucus and Microbiota in Mice

Targeted epithelial disruption impacts colonic mucus and microbiota in mice. Digestive Disease Week

Sa1754 Early Maternal Separation Leads to Abnormal Immune Response Against Commensal Microbiota in Adult Mice

Early maternal separation leads to abnormal immune response against commensal microbita in adult mice. 9. European Mucosal Immunology Group Meeting (EMIG)