Marianela Mego

Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study

Prebiotics have been shown to reduce abdominal symptoms in patients with functional gut disorders, despite that they are fermented by colonic bacteria and may induce gas‐related symptoms.

Intestinal gas homeostasis: disposal pathways

Patients with functional gut disorders frequently complain of gas‐related symptoms, but the role of intestinal gas in this context is not clear, because intestinal gas homeostasis is incompletely understood. Our aim was to compare the proportion of the gas produced by colonic fermentation that is evacuated per anus and that eliminated via alternative pathways.

Accumulative effect of food residues on intestinal gas production

As mean transit time in the colon is longer than the interval between meals, several consecutive meal loads accumulate, and contribute to colonic biomass. Our aim was to determine the summation effect of fermentable food residues on intestinal gas production.

Colonic content: effect of diet, meals, and defecation

The metabolic activity of colonic microbiota is influenced by diet; however, the relationship between metabolism and colonic content is not known. Our aim was to determine the effect of meals, defecation, and diet on colonic content.

High Resolution Esophageal Manometry in Patients with Chagas Disease: A Cross-Sectional Evaluation.

Introduction Gastrointestinal involvement affects 30–40% of the patients with chronic Chagas disease. Esophageal symptoms appear once the structural damage is established. Little is known about the usefulness of high resolution manometry to early identification of esophageal involvement. Method We performed a cross-sectional study at the Vall d’Hebron University Hospital (Barcelona, Spain) between May 2011 and April 2012. Consecutive patients diagnosed with Chagas disease in the chronic phase were offered to participate. All patients underwent a structured questionnaire about digestive symptoms, a barium esophagogram (Rezende classification) and an esophageal high resolution manometry (HRM). A control group of patients with heartburn who underwent an esophageal HRM in our hospital was selected. Results 62 out of 73 patients that were included in the study fulfilled the study protocol. The median age of the Chagas disease group (CG) was 37 (IQR 32–45) years, and 42 (67.7%) patients were female. Twenty-seven (43.5%) patients had esophageal symptoms, heartburn being the most frequent. Esophagogram was abnormal in 5 (8.77%). The esophageal HRM in the CG showed a pathological motility pattern in 14 patients (22.6%). All of them had minor disorders of the peristalsis (13 with ineffective esophageal motility and 1 with fragmented peristalsis). Hypotonic lower esophageal sphincter was found more frequently in the CG than in the control group (21% vs 3.3%; p<0.01). Upper esophageal sphincter was hypertonic in 22 (35.5%) and hypotonic in 1 patient. When comparing specific manometric parameters or patterns in the CG according to the presence of symptoms or esophagogram no statistically significant association were seen, except for distal latency. Conclusion The esophageal involvement measured by HRM in patients with chronic Chagas disease in our cohort is 22.6%. All the patients with esophageal alterations had minor disorders of the peristalsis. Symptoms and esophagogram results did not correlate with the HRM results.

Colonic gas homeostasis: Mechanisms of adaptation following HOST-G904 galactooligosaccharide use in humans

We have shown that a galactooligosaccharide prebiotic administration (HOST‐G904) initially increased intestinal gas production and this increase declined back to baseline after 2 week administration. Our aim was to determine the mechanism of microbiota adaptation; i.e., to determine whether the net reduction is due to decreased overall production or increased gas consumption.

Semi-automatic colonic content analysis for diagnostic

The analysis of the morphology and content of the gut is necessary in order to understand metabolic and functional gut activity and for diagnostic purposes. Magnetic resonance imaging (MRI) has become an important modality technique since it is able to visualize soft tissues using no ionizing radiation, and hence removes the need for any contrast agents. In the last few years, MRI of gastrointestinal function has advanced substantially, although scarcely any publication has been devoted to the analysis of the colon content. This paper presents a semi-automatic segmentation tool for the quantitative assessment of the unprepared colon from MRI images. This application has allowed for the analysis of the colon content in various clinical experiments. The results of the assessment have contributed to a better understanding of the functionality of the colon under different diet conditions. The last experiment carried out by medical doctors showed a marked influence of diet on colonic content, accounting for about 30% of the volume variations.

Effect of Chicory-derived Inulin on Abdominal Sensations and Bowel Motor Function

Goal: To determine the effect of a prebiotic chicory-derived inulin-type fructan on the tolerance of intestinal gas. Background: Subjects with gas-related complaints exhibit impaired handling of intestinal gas loads and we hypothesized that inulin would have a beneficial effect. Study: Placebo-controlled, parallel, randomized, double-blind trial. Subjects with abdominal symptoms and reduced tolerance of intestinal gas (selected by a pretest) received either inulin (8 g/d, n=18) or maltodextrin as a placebo (8 g/d, n=18) for 4 weeks. A gas challenge test (4 h jejunal gas infusion at 12 mL/min while measuring abdominal symptoms and gas retention for 3 h) was performed before and at the end of the intervention phase. Gastrointestinal symptoms and bowel habits (using daily questionnaires for 1 wk) and fecal bifidobacteria counts were measured before and at the end of the intervention. Results: Inulin decreased gas retention during the gas challenge test (by 22%; P=0.035 vs. baseline), while the placebo did not, but the intergroup difference was not statistically significant (P=0.343). Inulin and placebo reduced the perception of abdominal sensations in the gas challenge test to a similar extent (by 52% and 43%, respectively). Participants reported moderate gastrointestinal symptoms and normal bowel habits during baseline examination, and these findings remained unchanged in both groups during the intervention. Inulin led to a higher relative abundance of bifidobacteria counts (P=0.01 vs. placebo). Conclusions: A daily dose of inulin that promotes bifidobacteria growth and may improve gut function, is well tolerated by subjects with gastrointestinal complaints.

Assessment of Rectocolonic Morphology and Function in Patients with Chagas Disease in Barcelona (Spain)

The aim of this study was to determine the relationship between colonic symptoms, radiological abnormalities, and anorectal dysfunction in patients with Chagas disease. We performed a cross-sectional study of untreated patients diagnosed with Chagas disease. All patients were evaluated clinically (by a questionnaire for colonic symptoms based on Rome III criteria) and underwent a barium enema and anorectal manometry. A control group of patients with functional constipation and without Chagas disease was included in the study. Overall, 69 patients were included in the study: 42 patients were asymptomatic and 27 patients had abdominal symptoms according to Rome III criteria. Anorectal manometry showed a higher proportion of abnormalities in symptomatic patients than in asymptomatic ones (73% versus 21%, respectively; P < 0.0001). Megarectum was detected in a similar proportion in the different subgroups regardless of the presence of symptoms or abnormalities in anorectal functions. Among non-Chagas disease patients with functional constipation, 90% had an abnormal anorectal manometry study. Patients with Chagas disease present a high proportion of constipation with dyssynergic defecation in anorectal manometry but a low prevalence of impaired rectoanal inhibitory reflex, although these abnormalities may be nonspecific for Chagas disease. The presence of megarectum is a nonspecific finding.