The association of intestinal microbiota with obesity La microbiota intestinal: Un nuevo actor en el desarrollo de la obesidad

Intestinal microbiota (IM) plays a role in the development of obesity and its associated low-grade inflammation. Bacterial colonization of the gastrointestinal tract of germ-free mice (without microbiota) increases by 60% their fat mass, alters their fasting glucose and insulin levels, triples their hepatic triglycerides and induces adipocyte hypertrophy. IM favors fat storage in adipocytes through the inhibition of Fiaf (Fasting-Induced Adipocyte Factor), an inhibitor of lipoprotein lipase. Compared with normal weight subjects, the IM from obese exhibits a higher proportion of Firmicutes/Bacteroidetes and is more efficient in extracting energy from foodstuffs. The loss of bodyweight by a hypocaloric diet reverts the proportion of bacteria to that of lean subjects. The intake of a high fat diet also alters the IM, affecting intestinal barrier function and favoring endotoxinemia. These events increase oxidative and pro-inflammatory processes in plasma and peripheral tissues and increme

Phytochemicals: a new class of prebiotics

La microbiota intestinal (MI) es considerada como un nuevo blanco para la prevención y manejo nutricional de las alteraciones inflamatorias y metabólicas asociadas a las enfermedades crónicas no-transmisibles. Los prebióticos son principalmente fibras solubles cuyo consumo favorece el crecimiento de poblaciones bacterianas beneficiosas de la MI e impacta favorablemente la salud del consumidor. Esta revisión presenta a los fitoquímicos dietarios, que incluyen a más de 8.000 compuestos, como una nueva clase de prebióticos debido a su capacidad de estimular poblaciones de Lactobacillus, Bifidobacterium, Akkermansia y de bacterias productoras de butirato en el colon, a expensa de bacterias potencialmente dañinas como C. histolyticum. Además, los fitoquímicos son transformados por la MI en múltiples metabolitos que ejercen actividades biológicas a veces más potentes que la molécula inicial de la cual provienen. Individuos con distintos metabotipos han sido descritos de acuerdo a su capacidad de responder al consumo de isoflavonas, lignanos o elagitaninos, dependiendo de la presencia en su MI de bacterias capaces de transformar dichos polifenoles en equol, enterolactona/enterodiol y urolitinas, respectivamente, los cuales exhiben actividades biológicas. Valerolactonas y ácidos aromáticos también son producidos por la MI a través del metabolismo de las proantocianidinas. El efecto prebiótico de los fitoquímicos contribuiría a explicar los efectos saludables del consumo de frutas y verduras ricos en fitoquímicos.Intestinal microbiota (IM) is considered as a new target for the prevention and nutritional management of inflammatory and metabolic alterations associated with non-transmissible chronic diseases. Prebiotics are mainly soluble fibers whose consumption favors the growth of beneficial bacterial populations of the IM and positively impacts health. This review discusses dietary phytochemicals, which include more than 8,000 compounds, as a new class of prebiotics due to its ability to stimulate populations of Lactobacillus, Bifidobacterium, Akkermansia and butyrate producing bacteria in the colon at the expense of potentially harmful bacteria, such as C. histolyticum. In addition, phytochemicals are transformed by IM into a great array of metabolites exerting biological activities and are sometimes more potent than the initial molecule from which they are derived. Individuals with different metabotypes have been described according to their ability to respond to the consumption of isoflavones, lignans or ellagitannins, depending on the presence in their IM of bacteria capable of transforming these polyphenols into equol, enterolactone/enterodiol and urolithins, respectively, which exhibit biological activities. Valerolactones and aromatic acids are also produced by the IM through proanthocyanidin metabolism. The prebiotic effect of phytochemicals would help to explain the healthy effects associated with the consumption of fruits and vegetables rich in phytochemicals

Local and systemic liberation of cytokines in ulcerative colltis

Determination of plasmatic and tissular cytokine concentrations in inflammatory bowel diseases have frequently resulted in conflicting data. The aim of this study is to determine, in patients with ucerative colitis (UC), the levels of the proinflammatory cytokines IL-1β, IL-6, IFNγ and TNFα, liberated by peripheral blood mononuclear cells (PBMC) and lamina propria mononuclear cells (LPMC). Peripheral blood and colonic biopsies (5-10) were collected from 10 normal controls and 8 patients with UC. LPMC were isolated by collagenase digestion. LPMC and PBMC were cultured for 48h with pokeweed mitogen (PW) to induce cytokine production. Presence of IL-1β, IL-6, IFNγ and TNFα in the supernatant was detected using ELISA kits. Spontaneous production of IL-6 by PBMC were higher in UC than in controls (2029 pg/ml IC95[-165 - 4223] vs 572 pg/ml [-383 -1527] respectively, p=0.05) and also after activation with PW (14995 pg/ml [7759 - 22230] vs 6598 pg/ml [3240 - 9956] respectively, p=0.05). TNFα

Butyrate and the Fine-Tuning of Colonic Homeostasis: Implication for Inflammatory Bowel Diseases

This review describes current evidence supporting butyrate impact in the homeostatic regulation of the digestive ecosystem in health and inflammatory bowel diseases (IBDs). Butyrate is mainly produced by bacteria from the Firmicutes phylum. It stimulates mature colonocytes and inhibits undifferentiated malignant and stem cells. Butyrate oxidation in mature colonocytes (1) produces 70–80% of their energetic requirements, (2) prevents stem cell inhibition by limiting butyrate access to crypts, and (3) consumes oxygen, generating hypoxia and maintaining luminal anaerobiosis favorable to the microbiota. Butyrate stimulates the aryl hydrocarbon receptor (AhR), the GPR41 and GPR109A receptors, and inhibits HDAC in different cell types, thus stabilizing the gut barrier function and decreasing inflammatory processes. However, some studies indicate contrary effects according to butyrate concentrations. IBD patients exhibit a lower abundance of butyrate-producing bacteria and butyrate content. Additionally, colonocyte butyrate oxidation is depressed in these subjects, lowering luminal anaerobiosis and facilitating the expansion of Enterobacteriaceae that contribute to inflammation. Accordingly, gut dysbiosis and decreased barrier function in IBD seems to be secondary to the impaired mitochondrial disturbance in colonic epithelial cells

Aspetti strutturali e congiunturali della domanda vinicola nel Veneto

L'analisi della domanda al consumo di vino è effettuata attraverso l'approccio metodologico Almost Ideal Demand System, idoneo ad offrire una descrizione sintetica delle modalità di scelta al consumo delle singole tipologie vinicole all'interno della regione Veneto

Amoxicillin treatment modifies the composition of Bifidobacterium species in infant intestinal microbiota

Objectives: Amoxicillin is a beta-lactam antibiotic largely used in childhood. However only few studies described its impact on composition of children gut microbiota, in particular on Bifidobacterium populations considered as beneficial microorganisms. In this study, the impact on faecal Bifidobacterium species of a seven-day amoxicillin treatment was quantitatively and qualitatively assessed in infants during an episode of acute respiratory infection. Methods: Faecal samples from 31 infants were obtained on day 0 (just before amoxicillin therapy) and on day 7 (the end of therapy). Total DNA was extracted and bifidobacteria were quantified using real-time PCR. Predominant Bifidobacterium species were then identified using specific PCR-TTGE. Results: Bifidobacteria concentrations were not significantly altered by amoxicillin compared to the healthy group. However, amoxicillin treatment induced a complete disappearance of Bifidobacterium adolescentis species (occurrence rate of 0% versus 36.4% in healthy group, P < 0.001), a significant decrease in the occurrence rate of Bifidobacterium bifidum (23% versus 54.5% in healthy group, P < 0.05), but did not affect Bifidobacterium longum (93.5% versus 100% in healthy group) and Bifidobacterium pseudocatenulatum/B. catenulatum (about 55% in both groups). The number of Bifidobacterium species per microbiota significantly decreased from 2.5 1 for healthy group to 1.8 0.9 for treated infants (P < 0.05). Conclusions: This study showed that a 7 day amoxicillin treatment did not alter the counts of Bifidobacterium. However amoxicillin can have an impact by changing the microbiota at the species level and decreased the diversity of this population.This work was supported by Ecos (grant number C01S03)

Anti-inflammatory effect of microbial consortia during the utilization of dietary polysaccharides

© 2018 Elsevier Ltd The gut microbiome has a significant impact on host health, especially at the metabolic level. Dietary compounds arriving at the colon have a large influence on the composition of the gut microbiome. High fiber diets have been associated to health benefits that are mediated in great part by short chain fatty acids (SCFA). Gut microbial interactions are relevant for the utilization of complex carbohydrates in the gut microbiome. In this work we characterized the utilization of two dietary polysaccharides by combinations of representative adult gut microbes, and the impact of their activities on a cellular inflammation model. Paired combinations of Bifidobacterium adolescentis, Bacteroides dorei, Lactobacillus plantarum, Escherichia coli and Clostridium symbiosum were grown in inulin or xylan as carbon source. Their relative abundance, substrate consumption and major SCFAs produced were determined. Higher cell growth was observed during inulin consumption, and B. ado

Interleukin-6 and interferon-γ release from peripheral blood mononuclear cells and colonic lamina propria mononuclear cells from patients with ulcerative colitis Liberación de interleuquina-6 e interferón-γ por células mononucleares de la sangre y de muco

Background: Cytokines are involved in the pathogenesis of inflammatory bowel diseases such as ulcerative colitis and Crohn disease. Aim: To measure cytokine release by mononuclear cells of patients with ulcerative colitis. Patients and methods: Twelve patients subjected to a diagnostic colonoscopy were studied. Six had an ulcerative colitis and six did not have inflammatory changes in the colonic mucosa and were considered as control. Mononuclear cells were isolated from biopsies of colonic mucosa and from peripheral blood cultivated during 48 hours with pokeweed mitogen, and Interleukin 6 and interferon-γ were measured in their supernatants. Results: In patients with ulcerative colitis, interleukin 6 secretion by peripheral blood mononuclear cells was higher than in control subjects in the basal period (2212 ± 424 and 443 ± 174 pg/ml respectively p= 0.03) and after stimulation with pokeweed mitogen (16328 ± 1275 and 5462 ± 322 pg/ml respectively p = 0.03). No differences in interleuk

Gastric mucosal interleukin-8 in children colonized by Helicobacter pylori Niveles de interleuquina-8 en biopsias gástricas de niños colonizados por Helicobacter pylori

Background: Helicobacter pylori produces a gastric mucosal inflammation characterized by neutrophil infiltration, due to the liberation of interleukin-8. Aim: To measure interleukin-8 levels in gastric mucosa samples from children colonized by H. pylori. Patients and methods: Thirty one children that required an upper gastrointestinal endoscopy for diagnostic purpose were studied. Antral biopsies were obtained for pathological study, H. pylori detection using CLO-test and interleukin-8 determination by ELISA. Results: Nine children were not infected with H. pylori. Of these, six had a pathologically normal gastric mucosa and three had a mild chronic gastritis. Twenty two children were infected by H. pylori and all had a chronic gastritis with activity signs in 13. Mucosal interleukin-8 was higher in infected than in non infected children (59.7 (range 6.1-379.7) and 15.8 (range 3.9-104.1) pg/mg respectively p=0.029). Colonized children with an active chronic gastritis had higher interl