Emmanuel Barrat | Université de Nantes (original) (raw)

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Research paper thumbnail of Maturation_of_Colonic_permeability

Objectives: The intestinal barrier function is essential to limit the exposure of the organism to... more Objectives: The intestinal barrier function is essential to limit the exposure of the organism to potentially harmful substances, especially in the colon where large quantities of such substances are found. This function is thought to be immature in the neonate since the permeability in the small intestine is high at birth and declines during the postnatal period. However, due to technical limitations, the post-natal evolution of the colonic permeability has been determined neither in human nor in animals. In this study, we examined its time course in newborn rats. Methods: Rats, aged 5 days (d5) to d100, were mother-raised and naturally weaned from d16 to d21. The permeability of the cecum, proximal and distal colon to 4KDa-dextran, was assessed ex vivo in Ussing chambers. In addition, the mRNA expression of selected intercellular tight junction proteins was quantified in distal colon by real-time RT-PCR. Results: Whereas proximal colon displayed very limited post-natal modificatio...

Research paper thumbnail of O009 Effet des prébiotiques sur la synthèse protéique de la muqueuse colique : étude in vivo par les isotopes stables chez le rat nouveau-né en nutrition entérale

ABSTRACT Introduction et but de l’étude Le maintien de la masse protéique intestinale est une des... more ABSTRACT Introduction et but de l’étude Le maintien de la masse protéique intestinale est une des conditions de l’intégrité de la muqueuse intestinale, elle-même indispensable pour permettre à l’intestin d’assurer ses fonctions de “barrière”, et dépend de l’équilibre entre les vitesses de synthèse et de dégradation protéique. Or on connaît mal les facteurs qui régulent la synthèse protéique dans la muqueuse colique, particulièrement chez le nouveau-né. Le butyrate et les acides gras à chaîne courte issus du métabolisme des oligosaccharides prébiotiques sont les principaux carburants du colonocyte, et ont des effets trophiques sur le côlon adulte. Le but de cet étude était de déterminer 1) si les prébiotiques ont un effet trophique chez le nouveau-né, et 2) s’ils stimulent la synthèse protéique dans la muqueuse colique néonatale. Matériel et méthodes Trente huit rats nouveau-nés porteurs d’une gastrostomie mise en place par voie percutanée ont reçu du 5e au 18e jour de vie (sevrage), une alimentation entérale exclusive à l’aide d’un substitut de lait de rat, supplémenté ou non, après ran-domisation, en galacto- et fructo-oligosaccharides (GOS/FOS). Au 18e jour de vie, ils ont reçu en phase nourrie une perfusion entérale de L-[U-13C] valine durant 2 h avant sacrifice. Les enrichissements isotopiques ont été mesurés par spectrométrie de masse couplée à la chromatographie gazeuse. Le turnover protéique du corps entier a été calculé à partir de la 13C-valine libre sanguine, et la vitesse fractionnelle de synthèse (FSR) protéique, mesurée par l’incorporation du traceur dans les protéines de la muqueuse, rapportée à l’enrichissement de la valine libre intracellulaire de la muqueuse. Résultats Les résultats des 2 groupes (Tableau) ont été comparés par test de t non apparié. Conclusions Sur un modèle animal de nouveau-né prématuré, la supplémentation en prébiotiques GOS/FOS a un effet trophiqueTableau 1Poids corporel à J18, gTurnover protéiq g/kg/jPoids caceum mgFSR caecum % / jFSR colon prox,þ%/jFSR colon distal,þ%/jTémoins34 ±352±170,155± 0,003239 ±139215 ± 113221±125GOS/FOS33 ±439±90,223 ± 0,030265 ± 173177± 163153± 108P0,480,100,000040,680,510,14 sur le côlon, mais n’a pas d’effet sur la croissance, le turnover protéique du corps entier, et la vitesse fractionnelle de synthèse protéique dans la muqueuse.

Research paper thumbnail of Supplementation With Galactooligosaccharides and Inulin Increases Bacterial Translocation in Artificially Reared Newborn Rats

Pediatric Research, 2008

Supplementation of formulas with prebiotics enhances the growth of lactate producing bacteria, an... more Supplementation of formulas with prebiotics enhances the growth of lactate producing bacteria, and fecal lactate, and acetate levels in infants. High concentrations of organic acids in intestinal lumen have, however, been shown to impair the intestinal barrier function. To determine whether stimulating the colonic microbiotal metabolism with prebiotics would impair the neonatal intestinal barrier function, artificially reared rats were fed milk formula with or without a mixture of galactooligosaccharides/inulin (GOS/Inulin, 88/12; 5.6 g/L) from the 7th d of life (d7) until weaning (d20). At d18, GOS/inulin supplementation had increased the concentrations of acetate and lactate in colonic lumen. Although neither ileumassociated microbiota nor colonic permeability (assessed in Ussing chambers), nor the expression of tight junction claudin-2 and claudin-3 mRNA were altered, GOS/inulin supplementation was associated with increased bacterial translocation (BT) toward spleen. None of these effects persisted at d40. We conclude that GOS/inulin supplementation may increase BT in an immature gut. The balance between the potential infectious risk of BT vs. its putative beneficial effect on the maturation of neonatal immune system clearly warrants further study. Animals. Experiments were carried out in accordance with the recommendations of the local Animal Care and Use Committee of Nantes (France). The animal facilities were approved by the government agency in charge of experimental facilities at the French Department of Agriculture, the investigators were accredited by the National Veterinary Agency, and the "pup in the cup" model was approved as well by a veterinary practitioner from the National School of Veterinary Medicine. Male newborn rats, originated from 30 pregnant time-dated Sprague-Dawley dams (Elevage Janvier, Le Genest St Isle, France), were used in three consecutive sets of experiments. Ninety-five male pups (n ϭ 30; n ϭ 30; and n ϭ 35 in sets no. 1, 2, and 3, respectively) underwent noninvasive gastrostomy 5 d after delivery (d5) as described earlier . Four times a day, urination and defecation were induced by gentle stimulation of the anal/genital area of each rat pup. The amount of feces excreted was evaluated semiquantitatively according to a 0 -3 scale from d7 until d16, at which time the rats were able to defecate alone. During the third set of experiments, seven male pups from the same litters as gastrostomized pups and raised by their mother were also included for comparison.

Research paper thumbnail of Repeatability and relative validity of a quantitative food-frequency questionnaire among French adults

Food & Nutrition Research, 2012

Background: A 50-item self-administered food frequency questionnaire (FFQ) was developed for Fren... more Background: A 50-item self-administered food frequency questionnaire (FFQ) was developed for French adults, to assess the intake of energy, 10 macronutrients, 11 vitamins, and 11 minerals, and to be used in the context of a medical consultation. Objective: To assess the repeatability and relative validity of this FFQ compared to a 7-day diet record (7-DR). Design: A total of 54 and 100 French adults were included in the repeatability and validation studies, respectively. Repeatability was assessed using two FFQs, the second carried out 3 weeks after the first. In the validation study, subjects first completed the FFQ, then the 7-DR the following week. Energy and nutrient intakes were compared using Pearson correlation. The degree of misclassification by the FFQ, compared to the 7-DR, was calculated by a contingency table of quintiles. BlandÁAltman plots assessed the correlation between FFQ and 7-DR across the intake range. Results: Repeatability for intake, explored by Pearson correlation, was 0.62Á0.90 (median: 0.81). Relative validity, as determined by Pearson correlation for the nutrient intake derived from the FFQ and 7-DR, was 0.36Á0.80 (0.64). The FFQ tended to report higher fiber and micronutrient intake than 7-DR. Misclassification into opposite quintiles ranged 0Á6% (1%), whereas classification into same or adjacent quintiles ranged 59Á83% (74%). BlandÁAltman plots showed good agreement for most nutrients across the range of intake. Conclusion: This new FFQ showed a high repeatability and good relative validity, and thanks to its short length, should be a useful tool for rapidly evaluating the nutrient intake of French adults.

Research paper thumbnail of Maturation_of_Colonic_permeability

Objectives: The intestinal barrier function is essential to limit the exposure of the organism to... more Objectives: The intestinal barrier function is essential to limit the exposure of the organism to potentially harmful substances, especially in the colon where large quantities of such substances are found. This function is thought to be immature in the neonate since the permeability in the small intestine is high at birth and declines during the postnatal period. However, due to technical limitations, the post-natal evolution of the colonic permeability has been determined neither in human nor in animals. In this study, we examined its time course in newborn rats. Methods: Rats, aged 5 days (d5) to d100, were mother-raised and naturally weaned from d16 to d21. The permeability of the cecum, proximal and distal colon to 4KDa-dextran, was assessed ex vivo in Ussing chambers. In addition, the mRNA expression of selected intercellular tight junction proteins was quantified in distal colon by real-time RT-PCR. Results: Whereas proximal colon displayed very limited post-natal modificatio...

Research paper thumbnail of O009 Effet des prébiotiques sur la synthèse protéique de la muqueuse colique : étude in vivo par les isotopes stables chez le rat nouveau-né en nutrition entérale

ABSTRACT Introduction et but de l’étude Le maintien de la masse protéique intestinale est une des... more ABSTRACT Introduction et but de l’étude Le maintien de la masse protéique intestinale est une des conditions de l’intégrité de la muqueuse intestinale, elle-même indispensable pour permettre à l’intestin d’assurer ses fonctions de “barrière”, et dépend de l’équilibre entre les vitesses de synthèse et de dégradation protéique. Or on connaît mal les facteurs qui régulent la synthèse protéique dans la muqueuse colique, particulièrement chez le nouveau-né. Le butyrate et les acides gras à chaîne courte issus du métabolisme des oligosaccharides prébiotiques sont les principaux carburants du colonocyte, et ont des effets trophiques sur le côlon adulte. Le but de cet étude était de déterminer 1) si les prébiotiques ont un effet trophique chez le nouveau-né, et 2) s’ils stimulent la synthèse protéique dans la muqueuse colique néonatale. Matériel et méthodes Trente huit rats nouveau-nés porteurs d’une gastrostomie mise en place par voie percutanée ont reçu du 5e au 18e jour de vie (sevrage), une alimentation entérale exclusive à l’aide d’un substitut de lait de rat, supplémenté ou non, après ran-domisation, en galacto- et fructo-oligosaccharides (GOS/FOS). Au 18e jour de vie, ils ont reçu en phase nourrie une perfusion entérale de L-[U-13C] valine durant 2 h avant sacrifice. Les enrichissements isotopiques ont été mesurés par spectrométrie de masse couplée à la chromatographie gazeuse. Le turnover protéique du corps entier a été calculé à partir de la 13C-valine libre sanguine, et la vitesse fractionnelle de synthèse (FSR) protéique, mesurée par l’incorporation du traceur dans les protéines de la muqueuse, rapportée à l’enrichissement de la valine libre intracellulaire de la muqueuse. Résultats Les résultats des 2 groupes (Tableau) ont été comparés par test de t non apparié. Conclusions Sur un modèle animal de nouveau-né prématuré, la supplémentation en prébiotiques GOS/FOS a un effet trophiqueTableau 1Poids corporel à J18, gTurnover protéiq g/kg/jPoids caceum mgFSR caecum % / jFSR colon prox,þ%/jFSR colon distal,þ%/jTémoins34 ±352±170,155± 0,003239 ±139215 ± 113221±125GOS/FOS33 ±439±90,223 ± 0,030265 ± 173177± 163153± 108P0,480,100,000040,680,510,14 sur le côlon, mais n’a pas d’effet sur la croissance, le turnover protéique du corps entier, et la vitesse fractionnelle de synthèse protéique dans la muqueuse.

Research paper thumbnail of Supplementation With Galactooligosaccharides and Inulin Increases Bacterial Translocation in Artificially Reared Newborn Rats

Pediatric Research, 2008

Supplementation of formulas with prebiotics enhances the growth of lactate producing bacteria, an... more Supplementation of formulas with prebiotics enhances the growth of lactate producing bacteria, and fecal lactate, and acetate levels in infants. High concentrations of organic acids in intestinal lumen have, however, been shown to impair the intestinal barrier function. To determine whether stimulating the colonic microbiotal metabolism with prebiotics would impair the neonatal intestinal barrier function, artificially reared rats were fed milk formula with or without a mixture of galactooligosaccharides/inulin (GOS/Inulin, 88/12; 5.6 g/L) from the 7th d of life (d7) until weaning (d20). At d18, GOS/inulin supplementation had increased the concentrations of acetate and lactate in colonic lumen. Although neither ileumassociated microbiota nor colonic permeability (assessed in Ussing chambers), nor the expression of tight junction claudin-2 and claudin-3 mRNA were altered, GOS/inulin supplementation was associated with increased bacterial translocation (BT) toward spleen. None of these effects persisted at d40. We conclude that GOS/inulin supplementation may increase BT in an immature gut. The balance between the potential infectious risk of BT vs. its putative beneficial effect on the maturation of neonatal immune system clearly warrants further study. Animals. Experiments were carried out in accordance with the recommendations of the local Animal Care and Use Committee of Nantes (France). The animal facilities were approved by the government agency in charge of experimental facilities at the French Department of Agriculture, the investigators were accredited by the National Veterinary Agency, and the "pup in the cup" model was approved as well by a veterinary practitioner from the National School of Veterinary Medicine. Male newborn rats, originated from 30 pregnant time-dated Sprague-Dawley dams (Elevage Janvier, Le Genest St Isle, France), were used in three consecutive sets of experiments. Ninety-five male pups (n ϭ 30; n ϭ 30; and n ϭ 35 in sets no. 1, 2, and 3, respectively) underwent noninvasive gastrostomy 5 d after delivery (d5) as described earlier . Four times a day, urination and defecation were induced by gentle stimulation of the anal/genital area of each rat pup. The amount of feces excreted was evaluated semiquantitatively according to a 0 -3 scale from d7 until d16, at which time the rats were able to defecate alone. During the third set of experiments, seven male pups from the same litters as gastrostomized pups and raised by their mother were also included for comparison.

Research paper thumbnail of Repeatability and relative validity of a quantitative food-frequency questionnaire among French adults

Food & Nutrition Research, 2012

Background: A 50-item self-administered food frequency questionnaire (FFQ) was developed for Fren... more Background: A 50-item self-administered food frequency questionnaire (FFQ) was developed for French adults, to assess the intake of energy, 10 macronutrients, 11 vitamins, and 11 minerals, and to be used in the context of a medical consultation. Objective: To assess the repeatability and relative validity of this FFQ compared to a 7-day diet record (7-DR). Design: A total of 54 and 100 French adults were included in the repeatability and validation studies, respectively. Repeatability was assessed using two FFQs, the second carried out 3 weeks after the first. In the validation study, subjects first completed the FFQ, then the 7-DR the following week. Energy and nutrient intakes were compared using Pearson correlation. The degree of misclassification by the FFQ, compared to the 7-DR, was calculated by a contingency table of quintiles. BlandÁAltman plots assessed the correlation between FFQ and 7-DR across the intake range. Results: Repeatability for intake, explored by Pearson correlation, was 0.62Á0.90 (median: 0.81). Relative validity, as determined by Pearson correlation for the nutrient intake derived from the FFQ and 7-DR, was 0.36Á0.80 (0.64). The FFQ tended to report higher fiber and micronutrient intake than 7-DR. Misclassification into opposite quintiles ranged 0Á6% (1%), whereas classification into same or adjacent quintiles ranged 59Á83% (74%). BlandÁAltman plots showed good agreement for most nutrients across the range of intake. Conclusion: This new FFQ showed a high repeatability and good relative validity, and thanks to its short length, should be a useful tool for rapidly evaluating the nutrient intake of French adults.