| 1. |
- da Silva, Stéphanie
(författare)
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Conséquences d’un stress chronique sur la barrière de mucus intestinal chez le rat : effet du probiotique Lactobacillus farciminis
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background. Despite a large body of literature incriminating mucus alterations in the pathogenesis of Intestinal Bowel Diseases (IBD), structural and physical changes in the mucus layer remain poorly understood in the micro-inflammatory context of Irritable Bowel Syndrome (IBS). Moreover, some probiotic treatments prevent stress-induced intestinal epithelial barrier impairment but little is known about their influence on intestinal mucin structural modifications and mucus properties induced by stress. Thereby, this study aimed at evaluating whether (i) a chronic stress modified the number of gut goblet cells and Muc2 expression and O-glycosylation, (ii) L. farciminis (LF) treatment prevented these alterations and (iii) observed effects were related to the in vivo colonization capacity of LF.Main results and conclusions. Water Avoidance Stress (WAS) did not modify neither the number of intestinal goblet cells nor Muc2 expression. Mass Spectrometry analysis demonstrated that O-glycosylation of mucins was strongly affected by WAS, and confirmed in another model of IBS (maternal deprivation model). Under stress conditions, the mucus layer, showed a flattened morphology, probably indicative of a loss in its cohesive properties. The mucus layer alteration was, thus, in relation with epithelial barrier impairment and visceral hypersensitivity. LF administration prevented WAS-induced functional, biochemical and physical changes of mucus. The presence of LF in the ileum and colon was confirmed and we observed that Segmented Filamentous Bacteria (SFB) population was reduced by LF.Chronic stress induced functional changes in rats, as well as a shift in mucin O-glycosylation rather than changes in mucin expression, resulting in a loss of mucus layer cohesive properties. These results confirm that LF is a valuable probiotic in the IBS management.Methods. IBS Animal model (WAS and maternal deprivation), histological, Mass Spectrometry, Microscopy (Fluorescence, AFM, SEM and TEM), bacterial localization by Fluorescence In Situ Hybridization (FISH), qPCR, intestinal paracellular permeability, visceral sensitivity.
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| 2. |
- Dolo, A, et al.
(författare)
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Réponse humorale anti-Plasmodium falciparum AMA1 et MSP1 dans deux groupes ethniques vivant en sympatrie au Mali : [Humoral immune anti-Plasmodium falciparum AMA1 and MSP1 response in two ethnic groups living in sympatry in Mali].
- 2012
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Ingår i: Bulletin de la Société de Pathologie Exotique. - : Lavoisier. - 0037-9085 .- 1961-9049. ; 105:5, s. 364-369
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Tidskriftsartikel (refereegranskat)abstract
- Fulani of Mali are known for their lower susceptibility to Plasmodium falciparum malaria than their neighbours, the Dogon, despite similar transmission conditions. However, the mechanisms underlying these differences are poorly understood, particularly those concerning antigenspecific immune responses. The Apical Membrane Antigen 1 (AMA1) and the Merozoite Surface Antigen 1 (MSP1) are two malaria vaccine candidates, which play a pivotal role during the invasion of parasites into erythrocytes, and in the case of AMA1, of hepatocytes. Therefore, we analyzed the level of anti-AMA1 and anti-MSP1 antibodies (FVO and 3D7 alleles), by using ELISA (Enzyme Linked Immuno Sorbent Assay) to investigate whether there are differences between the two ethnic groups. Our results show that the splenic rate, the level of anti-AMA1 and anti-MSP1 were significantly higher in Fulani compared to Dogon; while the parasite rate was lower in Fulani group compared to Dogon. Our results suggest that the lower susceptibility of Fulani to malaria could be due to the higher specific humoral responses against AMA1 and MSP 1 in Fulani's ethnic group compared to Dogon.
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