Effect of Resistant Dextrin on Intestinal Gas Homeostasis and Microbiota

Previous studies have shown that a resistant dextrin soluble fibre has prebiotic properties with related health benefits on blood glucose management and satiety. Our aim was to demonstrate the effects of continuous administration of resistant dextrin on intestinal gas production, digestive sensations, and gut microbiota metabolism and composition. Healthy subjects (n = 20) were given resistant dextrin (14 g/d NUTRIOSE ®, Roquette Frères, Lestrem, France) for four weeks. Outcomes were measured before, at the beginning, end, and two weeks after administration: anal evacuations of gas during daytime; digestive perception, girth, and gas production in response to a standard meal; sensory and digestive responses to a comfort meal; volume of colonic biomass by magnetic resonance; taxonomy and metabolic functions of fecal microbiota by shotgun sequencing; metabolomics in urine. Dextrin administration produced an initial increase in intestinal gas production and gas-related sensations, followed by a subsequent decrease, which magnified after discontinuation. Dextrin enlarged the volume of colonic biomass, inducing changes in microbial metabolism and composition with an increase in short chain fatty acids-producing species and modulation of bile acids and biotin metabolism. These data indicate that consumption of a soluble fibre induces an adaptative response of gut microbiota towards fermentative pathways with lower gas productio

Mecanismo de producción de los síntomas digestivos funcionales

En esta tesis se abordan los mecanismos que producen los síntomas digestivos funcionales haciendo uso de técnicas no invasivas como son la tomografía computarizada y la resonancia magnética nuclear. Para el análisis de las imágenes y estudio de su contenido se han diseñado softwares especiales en nuestro laboratorio. En el primer estudio, empleando una metodología original y técnicas de inteligencia artificial se ha estudiado una cohorte grande de sujetos sanos para establecer el patrón de normalidad en la distribución de gas dentro del tubo digestivo. Además se incluyeron 88 enfermos con síntomas atribuidos al gas intestinal, a quienes se les estudió en situación basal y durante un episodio de distensión máxima. Los volúmenes medidos cuando el paciente se encontraba asintomático fueron similares a los de la cohorte de voluntarios sanos, sin embargo durante los episodios sintomáticos algunos pacientes presentaron un patrón de gas en el tubo digestivo fuera del rango de la normalidad. En el segundo estudio se midió el componente no gaseoso a nivel del colon tanto en sujetos sanos como en enfermos con distensión abdominal, observándose que el contenido sólido presenta una distribución uniforme con variaciones en relación a la ingesta. Los síntomas abdominales funcionales no se relacionan con variaciones del contenido no gaseoso del colon. En el tercer estudio, haciendo uso de imágenes abdominales obtenidas por resonancia magnética nuclear, se obtuvo una valoración fiable del colon y su contenido. Es así que el contenido no gaseoso presenta variaciones circadianas con un recambio sustancial producidas por la ingesta y la defecación. La ingesta de residuos no absorbibles en la dieta tiene una influencia marcada sobre el contenido no gaseoso del colon.In this thesis we have studied the mechanisms that produce functional gastrointestinal symptoms using non-invasive techniques such as computed tomography and magnetic resonance imaging. For image analysis and study of its contents we created special softwares in our laboratory. In the first study, using an original methodology and techniques of artificial intelligence we have studied a large cohort of healthy subjects to establish the pattern of normality in the distribution of gas within the digestive tract. In addition, 88 patients with symptoms attributed to intestinal gas were studied at baseline and during an episode of maximum distension. Volumes measured when the patient was asymptomatic were similar to those of the cohort of healthy volunteers, however during symptomatic episodes some patients had a pattern of gas in the digestive tract outside the range of normal. In the second study the non-gaseous component in the colon in both healthy subjects and in patients with abdominal distention was measured, showing that the solid content has a uniform distribution with variations related to ingestion of meals. Functional abdominal symptoms not related to changes in non-gaseous contents of the colon. In the third study, using abdominal images obtained by nuclear magnetic resonance, a reliable assessment of the colon and its contents was obtained. Thus the non-gaseous content presents circadian variations with substantial parts produced by ingestion and defecation. Intake nonabsorbable residues in the diet has a marked influence on colon nongaseous content

Mecanismo de producción de los síntomas digestivos funcionales

En esta tesis se abordan los mecanismos que producen los síntomas digestivos funcionales haciendo uso de técnicas no invasivas como son la tomografía computarizada y la resonancia magnética nuclear. Para el análisis de las imágenes y estudio de su contenido se han diseñado softwares especiales en nuestro laboratorio. En el primer estudio, empleando una metodología original y técnicas de inteligencia artificial se ha estudiado una cohorte grande de sujetos sanos para establecer el patrón de normalidad en la distribución de gas dentro del tubo digestivo. Además se incluyeron 88 enfermos con síntomas atribuidos al gas intestinal, a quienes se les estudió en situación basal y durante un episodio de distensión máxima. Los volúmenes medidos cuando el paciente se encontraba asintomático fueron similares a los de la cohorte de voluntarios sanos, sin embargo durante los episodios sintomáticos algunos pacientes presentaron un patrón de gas en el tubo digestivo fuera del rango de la normalidad. En el segundo estudio se midió el componente no gaseoso a nivel del colon tanto en sujetos sanos como en enfermos con distensión abdominal, observándose que el contenido sólido presenta una distribución uniforme con variaciones en relación a la ingesta. Los síntomas abdominales funcionales no se relacionan con variaciones del contenido no gaseoso del colon. En el tercer estudio, haciendo uso de imágenes abdominales obtenidas por resonancia magnética nuclear, se obtuvo una valoración fiable del colon y su contenido. Es así que el contenido no gaseoso presenta variaciones circadianas con un recambio sustancial producidas por la ingesta y la defecación. La ingesta de residuos no absorbibles en la dieta tiene una influencia marcada sobre el contenido no gaseoso del colon.In this thesis we have studied the mechanisms that produce functional gastrointestinal symptoms using non-invasive techniques such as computed tomography and magnetic resonance imaging. For image analysis and study of its contents we created special softwares in our laboratory. In the first study, using an original methodology and techniques of artificial intelligence we have studied a large cohort of healthy subjects to establish the pattern of normality in the distribution of gas within the digestive tract. In addition, 88 patients with symptoms attributed to intestinal gas were studied at baseline and during an episode of maximum distension. Volumes measured when the patient was asymptomatic were similar to those of the cohort of healthy volunteers, however during symptomatic episodes some patients had a pattern of gas in the digestive tract outside the range of normal. In the second study the non-gaseous component in the colon in both healthy subjects and in patients with abdominal distention was measured, showing that the solid content has a uniform distribution with variations related to ingestion of meals. Functional abdominal symptoms not related to changes in non-gaseous contents of the colon. In the third study, using abdominal images obtained by nuclear magnetic resonance, a reliable assessment of the colon and its contents was obtained. Thus the non-gaseous content presents circadian variations with substantial parts produced by ingestion and defecation. Intake nonabsorbable residues in the diet has a marked influence on colon nongaseous content

Mecanismo de producción de los síntomas digestivos funcionales /

En esta tesis se abordan los mecanismos que producen los síntomas digestivos funcionales haciendo uso de técnicas no invasivas como son la tomografía computarizada y la resonancia magnética nuclear. Para el análisis de las imágenes y estudio de su contenido se han diseñado softwares especiales en nuestro laboratorio. En el primer estudio, empleando una metodología original y técnicas de inteligencia artificial se ha estudiado una cohorte grande de sujetos sanos para establecer el patrón de normalidad en la distribución de gas dentro del tubo digestivo. Además se incluyeron 88 enfermos con síntomas atribuidos al gas intestinal, a quienes se les estudió en situación basal y durante un episodio de distensión máxima. Los volúmenes medidos cuando el paciente se encontraba asintomático fueron similares a los de la cohorte de voluntarios sanos, sin embargo durante los episodios sintomáticos algunos pacientes presentaron un patrón de gas en el tubo digestivo fuera del rango de la normalidad. En el segundo estudio se midió el componente no gaseoso a nivel del colon tanto en sujetos sanos como en enfermos con distensión abdominal, observándose que el contenido sólido presenta una distribución uniforme con variaciones en relación a la ingesta. Los síntomas abdominales funcionales no se relacionan con variaciones del contenido no gaseoso del colon. En el tercer estudio, haciendo uso de imágenes abdominales obtenidas por resonancia magnética nuclear, se obtuvo una valoración fiable del colon y su contenido. Es así que el contenido no gaseoso presenta variaciones circadianas con un recambio sustancial producidas por la ingesta y la defecación. La ingesta de residuos no absorbibles en la dieta tiene una influencia marcada sobre el contenido no gaseoso del colon.In this thesis we have studied the mechanisms that produce functional gastrointestinal symptoms using non-invasive techniques such as computed tomography and magnetic resonance imaging. For image analysis and study of its contents we created special softwares in our laboratory. In the first study, using an original methodology and techniques of artificial intelligence we have studied a large cohort of healthy subjects to establish the pattern of normality in the distribution of gas within the digestive tract. In addition, 88 patients with symptoms attributed to intestinal gas were studied at baseline and during an episode of maximum distension. Volumes measured when the patient was asymptomatic were similar to those of the cohort of healthy volunteers, however during symptomatic episodes some patients had a pattern of gas in the digestive tract outside the range of normal. In the second study the non-gaseous component in the colon in both healthy subjects and in patients with abdominal distention was measured, showing that the solid content has a uniform distribution with variations related to ingestion of meals. Functional abdominal symptoms not related to changes in non-gaseous contents of the colon. In the third study, using abdominal images obtained by nuclear magnetic resonance, a reliable assessment of the colon and its contents was obtained. Thus the non-gaseous content presents circadian variations with substantial parts produced by ingestion and defecation. Intake nonabsorbable residues in the diet has a marked influence on colon nongaseous content

Differential effects of western and mediterranean-type diets on gut microbiota : a metagenomics and metabolomics approach

Our aim was to determine the effect of diet on gut microbiota, digestive function and sensations, using an integrated clinical, metagenomics and metabolomics approach. We conducted a cross-over, randomised study on the effects of a Western-type diet versus a fibre-enriched Mediterranean diet. In 20 healthy men, each diet was administered for 2 weeks preceded by a 2-week washout diet. The following outcomes were recorded: (a) number of anal gas evacuations; (b) digestive sensations; (c) volume of gas evacuated after a probe meal; (d) colonic content by magnetic resonance imaging; (e) gut microbiota taxonomy and metabolic functions by shotgun sequencing of faecal samples; (f) urinary metabolites using untargeted metabolomics. As compared to a Western diet, the Mediterranean diet was associated with (i) higher number of anal gas evacuations, (ii) sensation of flatulence and borborygmi, (iii) larger volume of gas after the meal and (iv) larger colonic content. Despite the relatively little difference in microbiota composition between both diets, microbial metabolism differed substantially, as shown by urinary metabolite profiles and the abundance of microbial metabolic pathways. The effects of the diet were less evident in individuals with robust microbiotas (higher beta-diversity). To conclude, healthy individuals tolerate dietary changes with minor microbial modifications at the composition level but with remarkable variation in microbial metabolism