Intestin grêle

Résumé

vignette|Schéma de l'intestin grêle dans le système digestif L'intestin grêle est la partie de l'appareil digestif humain située entre l'estomac et le gros intestin (côlon). Il comprend un segment fixe, le duodénum, suivi de deux segments mobiles intrapéritonéaux, le jéjunum puis l'iléon. Anatomie Morphologie L'intestin grêle présente trois segments successifs :

le duodénum, intra-péritonéal, faisant suite au pylore ;
le jéjunum ;
l'iléon, sa portion terminale s'achevant par la valvule iléo-cæcale, qui le met en communication avec le cæcum puis le côlon.

L'intestin grêle est formé de sorte à amplifier les processus d'absorption :

sa longueur moyenne est et peut varier de 4 à , selon la technique de mesure utilisée. Ses différentes parties sont le duodénum (« douze » travers de doigt = ), le jéjunum (), et l'iléum (), avec un axe très sinueux ;
l'accroissement de sa surface par les valvules conniventes ou valvules de Kerckring, plis de la muqueuse et

Source officielle

https://fr.wikipedia.org/wiki/Intestin_gr%C3%AAle

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Intestinal organoid cocultures with microbes

Devanjali Dutta

This protocol comprises various methods to coculture organoids (particularly human small intestinal and colon organoids) with microbes, including microinjection into the lumen and periphery of 3D organoids and exposure of organoids to microbes in a 2D layer. Adult-stem-cell-derived organoids model human epithelial tissues ex vivo, which enables the study of host-microbe interactions with great experimental control. This protocol comprises methods to coculture organoids with microbes, particularly focusing on human small intestinal and colon organoids exposed to individual bacterial species. Microinjection into the lumen and periphery of 3D organoids is discussed, as well as exposure of organoids to microbes in a 2D layer. We provide detailed protocols for characterizing the coculture with regard to bacterial and organoid cell viability and growth kinetics. Spatial relationships can be studied by fluorescence live microscopy, as well as scanning electron microscopy. Finally, we discuss considerations for assessing the impact of bacteria on gene expression and mutations through RNA and DNA sequencing. This protocol requires equipment for standard mammalian tissue culture, or bacterial or viral culture, as well as a microinjection device.

NATURE PORTFOLIO2021

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SPROUTY2 is a β-catenin and FOXO3a target gene indicative of poor prognosis in colon cancer

Anja Irmisch, Paloma Ordonez Moran

SPROUTY2 (SPRY2) is an intracellular regulator of receptor tyrosine kinase signaling involved in cell growth, differentiation and tumorigenesis. Here, we show that SPRY2 is a target gene of the Wnt/beta-catenin pathway that is abnormally activated in more than 90% of colon carcinomas. In human colon cancer cells, SPRY2 expression is induced by beta-catenin in co-operation with the transcription factor FOXO3a instead of lymphoid enhancer factor/T-cell factor proteins. We found binding of beta-catenin to the SPRY2 promoter at FOXO3a response elements. In vivo, cells marked by nuclear beta-catenin and FOXO3a express SPRY2 in proliferative epithelial tissues, such as intestinal mucosa and epidermis. Consistently, inducible beta-catenin deletion in mice reduced Spry2 expression in the small intestine. Moreover, SPRY2 protein expression correlated with nuclear beta-catenin and FOXO3a colocalization in human colon carcinomas. Importantly, the amount of SPRY2 protein correlated with shorter overall survival of colon cancer patients. Our data reveal SPRY2 as a novel Wnt beta-catenin and FOXO3a target gene indicative of poor prognosis in colon cancer.

Nature Publishing Group2014

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Colorectal carcinoma (CRC) as a major health problem in industrialized countries is highly preventable and can be successfully treated in the early stages. However, incidence and mortality of CRC has increased over the last two decades. The reason could be that the current recommended options for screening are costly, unpleasant for patients, have low sensitivity and poor accessibility for screening. These reasons provide a strong rationale for the development of a new method. Opto-magnetic imaging spectroscopy (OMIS) as a new imaging method for the characterisation of various materials, including human tissues, is based on light-matter interaction, using a Poincare sphere for light properties and a Bloch sphere for electron properties, and allows the detection of biophysical characteristics within human tissue samples. Compared with histopathology examination, the OMIS method achieved an accuracy of 92.59% using Multilayer Perceptron Neural Network as a classifier, and 89.87% using Naive-Bayes, respectively. The obtained results, based on the investigation of 316 samples, both tumour and normal mucosa (162 cancer cases), strongly suggest that the new non-invasive OMIS method might be used for tissue characterization ex vivo to discriminate between the healthy and carcinoma state of the colon. However, it opens up the possibility of using the same method in in vivo studies to assist physicians in targeting biopsies of colorectal tissue.

2019

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