Antibiotics,gut microbiota,and irritable bowel syndrome:What are the relations?

Irritable bowel syndrome(IBS)is a functional gastrointestinal disorder in which recurrent abdominal pain is associated with defecation or a change in bowel habits(constipation,diarrhea,or both),and it is often accompanied by symptoms of abdominal bloating and distension.IBS is an important health care issue because it negatively affects the quality of life of patients and places a considerable financial burden on health care systems.Despite extensive research,the etiology and underlying pathophysiology of IBS remain incompletely understood.Proposed mechanisms involved in its pathogenesis include increased intestinal permeability,changes in the immune system,visceral hypersensitivity,impaired gut motility,and emotional disorders.Recently,accumulating evidence has highlighted the important role of the gut microbiota in the development of IBS.Microbial dysbiosis within the gut is thought to contribute to all aspects of its multifactorial pathogenesis.The last few decades have also seen an increasing interest in the impact of antibiotics on the gut microbiota.Moreover,antibiotics have been suggested to play a role in the development of IBS.Extensive research has established that antibacterial therapy induces remarkable shifts in the bacterial community composition that are quite similar to those observed in IBS.This suggestion is further supported by data from cohort and case-control studies,indicating that antibiotic treatment is associated with an increased risk of IBS.This paper summarizes the main findings on this issue and contributes to a deeper understanding of the link between antibiotic use and the development of IBS.

Factors that impact health-related quality of life in adults with celiac disease:A multicenter study

AIM: To evaluate the factors involved in the impairment of health-related quality of life (HRQOL) in patients with celiac disease.METHODS: A multicenter, cross-sectional prospective study was performed in patients with celiac disease who completed two HRQOL questionnaires: the gastrointestinal quality of life index (GIQLI) and the EuroQol-5D (EQ).RESULTS: Three hundred and forty patients (163 controlled with a gluten-free diet, and 177 newly diagnosed with a normal diet) were included. The GIQLI score was significantly better in patients on a gluten-free diet (GFD) than in non-treated patients on their usual diet, both in terms of the overall score (3.3 vs 2.7, respectively; P < 0.001), as well as on the individual questionnaire dimensions. Both the preference value of the EQ as the visual analogue scale were significantly better in treated than in non-treated patients (0.93 vs 0.72 P < 0.001 and 80 vs 70 P < 0.001, respectively). Variables significantly associated with a worse HRQOL score were female gender, failure to adhere to a GFD, and symptomatic status.CONCLUSION: In untreated celiac disease, the most important factors that influence patient perception of health are the presence of symptoms and a normal diet. HRQOL improves to levels similar to those described in the general population in celiac disease patients well controlled with a GFD.

Modulation of gastric accommodation by duodenal nutrients

AIM： To determine the relative potency and contribution of intestinal nutrients to net gastric accommodative relaxation and conscious perception. METHODS： In 12 healthy subjects, we randomly tested duodenal loads of lipids and carbohydrates （12 mL administered in 4 rain） at various caloric concentrations （0.0125-0.8 kcal/mL） separated by 12-24 rain wash-out periods of saline infusion. Maximal gastric relaxation was induced at the end of each experiment by i.v glucagon （5 μg/kg）, as reference. The reflex gastric response was measured by a barostat, and symptom perception by a 0-6 score questionnaire. RESULTS： Upids induced a dose-response gastric relaxation with a steep and early rise. Maximal effect （179±42 mL relaxation） reached at a relatively low concentration （0.2 kcal/mL）, maximal lipid-induced relaxation was 61±6% of the glucagon effect. By contrast, duodenal infusion of carbohydrates induced weaker relaxation that became significant only at the high end of the physiological concentration range （65±14 ml with 0.8 kcal/mL）. Intestinal nutrient loads, either of lipid or carbohydrates, did not induce significant changes in perception （0.6±0.4 and 0.1±0.4 score increase for the highest concentrations, respectively）. CONCLUSION： Chyme entering the small bowel induces nutrient-spedfic gastric relaxatory reflexes by a physiologically saturable mechanism. Normally, neither the intestinal nutrient load nor the gastric accommodative response is perceived.

肛门性便秘对生物反馈疗法的反应

Objective. Biofeedback is considered an effective treatment for anal constipa tion, but a substantial proportion of patients fail to improve. Our aim was to i dentify the key predictors of outcome using a comprehensive standardized evaluat ion of anorectal function. Material and methods. We retrospectively analysed the clinical and physiological data of 148 patients consecutively treated for const ipation due to functional outlet obstruction by biofeedback. Clinical evaluation was performed by means of a structured questionnaire. Anorectal evaluation incl uded anal pressure, neural reflexes, defecatory dynamics, rectal compliance, rec tal sensitivity and balloon expulsion test. Biofeedback treatment was performed using a manometric technique. The clinical response to biofeedback treatment was evaluated as good (improvement of constipation) or poor (no improvement or wors ening). Results. Of the 148 patients included, 112 (86 F, 26 M; age range 8- 67 years) were followed- up for between 1 and 44 months, and 66% had a good res ponse to treatment. The response depended on the severity of the defecatory dysf unction. Thus, lack of anal relaxation during straining and inability to evacuat e a 1 ml intrarectal balloon were inversely related to physiological variables r elated to therapeutic success. Among the 49 patients with absent anal relaxation , 51% had a good response to treatment (versus 78% in patients with partial relaxation; p < 0.01), and among the 29 patients with failed balloon expulsion, 48% responded to treatment (versus 74% in patients able to evacuate ≥ 1 ml intrarectal balloon; p < 0.05). Conclusions. Even in the presence of negative p redictors, biofeedback is a valuable treatment option in a substantial proportio n of constipated patients.

腹部胀气患者的肠道气体反射控制受损

Background: Patients with abdominal bloating and distension exhibit impaired transit of intestinal gas which may lead to excessive gas retention and symptoms . Furthermore, we have previously shown that intestinal gas transit is normally accelerated by rectal distension. We hypothesise that in patients with functiona l bloating this modulatory mechanism fails and impairs gas transit. Methods: In 12 healthy subjects and eight patients with abdominal bloating we compared, by p aired studies, the effect of rectal versus sham distension on intestinal gas tra nsit. Gas was infused into the jejunum (12 ml/min) for three hours with simultan eous perfusion of lipids into the duodenum (Intralipid 1 kcal/min) while measuri ng evacuation of gas per rectum. Results: In healthy subjects, duodenal lipid in fusion produced gas retention (409 (68) ml) which was prevented by rectal disten sion (90 (90) ml; p<0.05 v sham distension). In contrast, rectal distension in p atients with abdominal bloating failed to reduce lipid induced gas retention (77 1 (217) ml retention during rectal distension v 730 (183) ml during sham distens ion; NS; p<0.05 v healthy controls for both). Conclusion: Failure of distension related reflexes impairs intestinal gas propulsion and clearance in patients wit h abdominal bloating.