References of "Nollevaux, Geraldine"
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See detailReducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines
Poelaert, Christine; Nollevaux, Geraldine; Boudry, Christelle et al

in Animal (in press)

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by ... [more ▼]

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na2S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na2S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO2 and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na2S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar ( P>0.10) for the three reducing agents whereas the maximum rate of gas production ( Rmax) was reduced ( P<0.05) when carbohydrate ingredients were fermented with cysteine-HCl in comparison to Na2S and the control. For all ingredients, total SCFA production was similar ( P>0.10) after 24 h of fermentation with Na2S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher ( P<0.05) for protein (36.5% and 9.7% for casein and soybean proteins, respectively) than for carbohydrate (<4%) ingredients. Only fermentation residues of casein showed a possible cytotoxic effect regardless of the reducing agent ( P<0.05). Concerning the microbial composition of the fermentation broth, most significant differences in phyla and in genera ascribable to the reducing agent were found with potato starch and casein. In conclusion, saturating the incubation media with CO2 seems sufficient to generate a suitable anaerobic environment for intestinal microbes and the use of a reducing agent can be omitted. [less ▲]

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See detailRapport scientifique et technique final du projet HYDRASANTE
Boudry, Christelle ULiege; François, Emmanuelle ULiege; Nollevaux, Géraldine et al

Report (2013)

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See detailRapport scientifique et technique du projet HYDRASANTE (annee 3)
Boudry, Christelle ULiege; François, Emmanuelle ULiege; Nollevaux, Géraldine et al

Report (2013)

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See detailDevelopment of a serum-free co-culture of human intestinal epithelium cell-lines (Caco-2/HT29-5M21)
Nollevaux, Géraldine; Deville, Christelle ULiege; Elmoualij, Benaïssa ULiege et al

in BMC Cell Biology (2006), 7

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel ... [more ▼]

Background: The absorptive and goblet cells are the main cellular types encountered in the intestine epithelium. The cell lineage Caco-2 is a model commonly used to reproduce the features of the bowel epithelium. However, there is a strong debate regarding the value of Caco-2 cell culture to mimick in vivo situation. Indeed, some authors report in Caco-2 a low paracellular permeability and an ease of access of highly diffusible small molecules to the microvilli, due to an almost complete lack of mucus. The HT29-5M21 intestinal cell lineage is a mucin-secreting cellular population. A co-culture system carried out in a serum-free medium and comprising both Caco-2 and HT29-5M21 cells was developed. The systematic use of a co-culture system requires the characterization of the monolayer under a given experimental procedure. Results: In this study, we investigated the activity and localization of the alkaline phosphatase and the expression of IAP and MUC5AC genes to determine a correlation between these markers and the cellular composition of a differentiated monolayer obtained from a mixture of Caco-2 and HT29-5M21 cells. We observed that the culture conditions used ( serum-free medium) did not change the phenotype of each cell type, and produced a reproducible model. The alkaline phosphatase expression characterizing Caco-2 cells was influenced by the presence of HT29-5M21 cells. Conclusion: The culture formed by 75% Caco-2 and 25% HT29-5M21 produce a monolayer containing the two main cell types of human intestinal epithelium and characterized by a reduced permeability to macromolecules. [less ▲]

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See detailIn vitro transport studies of nifedipine nanoparticles across Caco-2/HT29- 5M21 cultures and co-cultures
Hecq, Julien; Nollevaux, Géraldine; Deleers, M. et al

Poster (2006)

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See detailNifedipine nanocrystals: pharmacokinetic evaluation in the rat and permeability studies in Caco-2/HT29-5M21 (co)-cultures
Hecq, Julien; Nollevaux, Géraldine; Deleers, M. et al

in Journal of Drug Delivery Science and Technology (2006), 16(6, NOV-DEC), 437-442

Poorly water-soluble drugs such as nifedipine (NIF) (similar to 20 mu g/mL) offer challenging problems in drug formulation as poor solubility is generally associated with poor dissolution characteristics ... [more ▼]

Poorly water-soluble drugs such as nifedipine (NIF) (similar to 20 mu g/mL) offer challenging problems in drug formulation as poor solubility is generally associated with poor dissolution characteristics and thus with poor oral bioavailability (BCS class H drugs). In order to enhance these characteristics, formulation of NIF as nanocrystals was carried out. NIF nanoparticles (NP) were prepared using high-pressure homogenization (HPH). Solubility and dissolution characteristics have been reported in previous work to be significantly enhanced for NIF NP. Influence of NIF particle size on NIF permeation rate across intestinal cell models (Caco-2 and HT29-5M21 cultures and co-cultures) was investigated in order to complement these promising in vitro data. Apical to basolateral transfer studies were carried out across Caco-2 and HT29-5M21 cultures and co-cultures. Caco-2/HT29-5M21 co-cultures (seeding ratio 3: 1) were evaluated to better represent in vivo intestinal conditions. The influence of chitosan in the NIF NP formulation with regard to in vitro NIF permeation rate was also evaluated. These studies showed that NIF permeation rate across the different in vitro models evaluated can be significantly enhanced (approximate to 6-fold) by formulation of NIF as nanoparticles. No significant difference was observed either in the presence of chitosan in the formulation or between the three cell models evaluated. To complement these observations, preliminary in vivo pharmacokinetic evaluations in Sprague-Dawley rats, in the fed and fasted states, were also carried out for both un-milled NIF and NIF NP. [less ▲]

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See detailModulation of intestinal urea cycle by dietary spermine in suckling rat
Gharbi, Myriam ULiege; Powroznik, Brigitte; Mazzucchelli, Gabriel ULiege et al

in Biochemical and Biophysical Research Communications (2005), 336(4), 1119-1124

Argininosuccinate synthetase, an ubiquitous enzyme in mammals, catalyses the formation of argininosuccinate, the precursor of arginine. Arginine is recognised as an essential amino acid in foetuses and ... [more ▼]

Argininosuccinate synthetase, an ubiquitous enzyme in mammals, catalyses the formation of argininosuccinate, the precursor of arginine. Arginine is recognised as an essential amino acid in foetuses and neonates, but also as a conditionally essential amino acid in adults. Argininosuccinate synthetase is initially expressed in enterocytes during the developmental period, it disappeared from this organ then appeared in the kidneys. Although the importance of both intestinal and renal argininosuccinate synthetases has been recognised for a long time, nutrients have not yet been identified as inducers of the gene expression. In the context of a proteomic screening of intestinal modifications induced by dietary spermine in suckling rats, we showed that argininosuccinate synthetase and carbamoyl phosphate synthase disappeared from enterocytes after this treatment. The disappearance of argininosuccinate synthetase in small intestine was confirmed by immunodetection. Expression of carbamoyl phosphate synthase and argininosuccinate synthetase coding genes decreased also after spermine administration. Expression of other urea cycle enzyme coding genes was modulated by spermine administration: argininosuccinate lyase decreased and arginase increased. Our results fit with the developmental variation of argininosuccinate synthetase and carbamoyl phosphate synthase. Modulation of the gene expression for several urea cycle enzymes suggests a coordination between all the pathway steps and switch toward polyamine (or proline and glutamate) biosynthesis from ornithine. (c) 2005 Elsevier Inc. All rights reserved. [less ▲]

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