Management of the irritable bowel syndrome

Review of the Patient Burden and Therapeutic Landscape of Irritable Bowel Syndrome with Constipation in the United States

Irritable bowel syndrome (IBS) is a common disorder of the gut-brain axis. IBS with constipation (IBS-C) accounts for approximately one-third of IBS cases and is associated with substantial burden of illness and decreased quality of life. This narrative review provides an overview of the current and upcoming treatment options and disease management for IBS-C from a US perspective and discusses the importance of the relationship between patient and health care provider in diagnosis and treatment. A positive diagnostic strategy for IBS-C is recommended, based on clinical history, physical examination, and minimal laboratory tests. An effective communication strategy between patients and health care professionals is essential to ensure early diagnosis and reduce both health care costs and overall disease burden. Treatment typically begins with lifestyle interventions and nonpharmacologic options, such as dietary interventions, fiber supplements, and osmotic laxatives. In patients with inadequate response to these therapies, 4 currently available therapies (lubiprostone, linaclotide, plecanatide, and tenapanor) approved by the US Food and Drug Administration may relieve IBS-C symptoms. These agents are generally well tolerated and efficacious in improving IBS-C symptoms, including constipation and abdominal pain. In patients with persistent abdominal pain and/or psychological symptoms, brain-gut behavioral therapy or neuromodulator therapy may be beneficial.

Development and Validation of a High-Performance Liquid Chromatography Method to Quantify Marker Compounds in Lysimachia vulgaris var. davurica and Its Effects in Diarrhea-Predominant Irritable Bowel Syndrome

Irritable bowel syndrome (IBS), a common gastrointestinal disorder worldwide, is characterized by chronic abdominal pain, bloating, and disordered defecation. IBS is associated with several factors, including visceral hypersensitivity, gut motility, and gut-brain interaction disorders. Because currently available pharmacological treatments cannot adequately improve symptoms and may cause adverse effects, the use of herbal therapies for managing IBS is increasing. Lysimachia vulgaris var. davurica (LV) is a medicinal plant used in traditional medicine to treat diarrhea. However, information on whether LV can effectively improve diarrhea-predominant IBS (IBS-D) remains limited. In this study, using an experimental mouse model of IBS-D, we elucidated the effects of the LV extract. The methanol extract of LV decreased fecal pellet output in the restraint stress- or 5-hydroxytryptamine (5-HT)-induced IBS mouse model and inhibited 5-HT-mediated [Ca2+]i increase in a dose-dependent manner. Furthermore, we developed and validated a high-performance liquid chromatography method using two marker compounds, namely, chlorogenic acid and rutin, for quality control analysis. Our study results suggest the feasibility of the methanol extract of LV for developing therapeutic agents to treat IBS-D by acting as a 5-HT3 receptor antagonist.

Role of Baseline Gut Microbiota on Response to Fiber Intervention in Individuals with Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is one of the most prevalent functional gut disorders in the world. Partially hydrolyzed guar gum, a low-viscosity soluble fiber, has shown promise in the management of IBS-related symptoms. In this study, we aimed to determine if an individual's baseline gut microbiota impacted their response to a partially hydrolyzed guar gum intervention. Patients diagnosed with IBS undertook a 90-day intervention and follow-up. IBS symptom severity, tolerability, quality-of-life, and fecal microbiome composition were recorded during this study. Patients with normal microbiota diversity (Shannon index ≥ 3) showed significant improvements to IBS symptom scores, quality-of-life, and better tolerated the intervention compared to patients with low microbiota diversity (Shannon index < 3). Our findings suggest that an individual's baseline microbiome composition exerts a substantial influence on their response to fiber intervention. Future investigations should explore a symbiotic approach to the treatment of IBS.

Prevalence and risk factors of belching disorders: A cross-sectional study among freshman college students

OBJECTIVES

Belching disorders seriously affect quality of life; however, their prevalences and risk factors remain unknown. The aim of our study was to determine the prevalence and risk factors, particularly lifestyle factors, of belching disorders among freshman college students in central China.

METHODS

A cross-sectional study was conducted in September 2019 in Huazhong University of Science and Technology (Wuhan, Hubei Province, China). The subjects were asked to complete a self-administered questionnaire for data collection, including sociodemographic information, lifestyle factors, and gastrointestinal symptoms. Belching disorder was diagnosed based on the Rome IV criteria. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for belching disorders.

RESULTS

A total of 3335 subjects were enrolled, and 78.26% were men. Among them, 1.95% (65/3335) reported belching disorders. Significant differences in the Pittsburgh Sleep Quality Index (PSQI), Student-Life Stress Inventory (SLSI) scores, and consumption of whole grains, black tea, coffee were found between the belching and non-belching groups. Multivariate logistic regression analysis showed that coffee consumption at least once weekly and a high total SLSI score (over mean + standard deviation) were independent risk factors for belching disorders, while intake of whole grains at least once weekly was a protective factor.

CONCLUSIONS

Excessive belching is a common disorder among freshman college students in central China. Lifestyle factors, including consumption of whole grains and coffee, and stress, were associated with belching disorders. Therefore, dietary intervention may be a potential management for belching disorders.

Physical activity for treatment of irritable bowel syndrome

BACKGROUND

Current recommendations for people with irritable bowel syndrome (IBS) to partake in physical activity are based on low-level evidence, do not incorporate evidence from all available randomised controlled trials (RCTs) and provide little information regarding potential adverse effects.

OBJECTIVES

To assess the benefits and harms of physical activity interventions in adults diagnosed with irritable bowel syndrome and to explore possible effect moderators including type, setting and nature of physical activity interventions.

SEARCH METHODS

We searched nine electronic databases including CENTRAL, MEDLINE and Embase to 5 November 2021. We handsearched reference lists and sought unpublished studies through trial registries.

SELECTION CRITERIA

We included RCTs involving adults (aged 18 years or older) diagnosed with IBS and conducted in any setting comparing a physical activity intervention with no intervention, usual care or wait-list control group or another physical activity intervention group and assessing a validated measure of symptoms, quality of life or bowel movement.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected studies for inclusion, extracted study data, and performed risk of bias and GRADE assessments to assess the certainty of evidence. We pooled studies that evaluated similar outcomes using a random-effects meta-analysis, and synthesised data from other studies narratively.

MAIN RESULTS

We included 11 RCTs with data for 622 participants. Most (10/11) were set in high- or middle- to high-income countries, with five involving supervised physical activity, three unsupervised activity and three a mix of supervised and unsupervised activity. No trial was at low risk of bias. Four trials specified a minimally important difference for at least one assessed outcome measure. Data for 10 trials were obtained from published journal articles, with data for one obtained from an unpublished Masters degree thesis. Irritable bowel syndrome symptoms Six RCTs assessed the effectiveness of a physical activity intervention compared with usual care on global symptoms of IBS. Meta-analysis of five studies showed an observed improvement in reported symptoms following physical activity (standardised mean difference (SMD) -0.93, 95% confidence interval (CI) -1.44 to -0.42; 185 participants). We rated the certainty of evidence for this outcome as very low due to unclear and high risk of bias, inconsistency and imprecision from sparse data. This means physical activity may improve IBS symptoms but the evidence is very uncertain. The results of the remaining study supported the meta-analysis but were at unclear risk of bias and sample size was small. Two studies assessed the effectiveness of a yoga intervention compared with a walking intervention on global IBS symptoms. Meta-analysis of these two studies found no conclusive evidence of an effect of yoga compared with walking on IBS symptoms (SMD -1.16, 95% CI -3.93 to 1.62; 124 participants). We rated the certainty of evidence as very low, meaning the evidence is very uncertain about the effect of yoga interventions compared with walking interventions on IBS symptoms. Two studies assessed the effectiveness of a physical activity intervention (yoga) compared with medication. One reported no observed difference in global IBS symptoms, though CIs were wide, suggesting uncertainty in the observed estimates and risk of bias was high (MD -1.20, 95% CI -2.65 to 0.25; 21 participants). We excluded IBS symptom data for the remaining study as it used a non-validated method. One study compared a yoga intervention with a dietary intervention and reported an observed improvement in symptoms with both interventions but neither intervention was superior to the other. Quality of life Five RCTs assessed the impact of physical activity on self-reported quality of life compared with usual care. Meta-analysis of data from four studies found no improvement in quality of life following a physical activity intervention (SMD 1.17, 95% CI -0.30 to 2.64; 134 participants; very low certainty due to risk of bias, inconsistency and imprecision). We rated the certainty of evidence as very low, meaning the evidence is very uncertain about the effect of physical activity interventions on quality-of-life outcomes in people with IBS. One study assessed the impact on quality of life of a yoga intervention compared with walking and observed an improvement in the yoga group (MD 53.45, 95% CI 38.85 to 68.05; 97 participants ).  One study reported no observed difference in quality of life between a yoga and a dietary intervention. Abdominal pain Two trials assessed the impact of physical activity compared with usual care on reported abdominal pain. Meta-analysis found no improvement in abdominal pain with physical activity compared with usual care (SMD 0.01, 95% CI -0.48 to 0.50; 64 participants). We rated the certainty of the evidence as very low due to risk of bias and imprecision, meaning the evidence is very uncertain about the effect of physical activity interventions on abdominal pain in people with IBS. One study assessing the impact of a yoga intervention compared with walking advice reported no observed differences between groups on abdominal pain. One study comparing a yoga intervention with a dietary intervention found neither intervention had a more beneficial impact than the other and both interventions did not conclusively reduce abdominal pain. There was insufficient evidence to adequately assess adverse effects associated with physical activity due to a lack of reporting in trials. One study reported a musculoskeletal injury in a yoga intervention group but this did not result in withdrawal from the study.

AUTHORS' CONCLUSIONS

Findings from a small body of evidence suggest that physical activity comprising of yoga, treadmill exercise or support to increase physical activity may improve symptoms but not quality of life or abdominal pain in people diagnosed with IBS but we have little confidence in these conclusions due to the very low certainty of evidence. The numbers of reported adverse events were low and the certainty of these findings was very low for all comparisons, so no conclusions can be drawn. Discussions with patients considering physical activity as part of symptom management should address the uncertainty in the evidence to ensure fully informed decisions. If deemed sufficiently important to patients and healthcare providers, higher quality research is needed to enable more certain conclusions.

Tegaserod for the Treatment of Irritable Bowel Syndrome

Background: Tegaserod (Zelnorm®) is a 5-hydroxytryptamine (serotonin) type 4 receptor agonist for the treatment of hypomotility disorders of the lower gastrointestinal tract associated with the irritable bowel syndrome with constipation (IBS-C).

Objective: The authors provide the reader with a better understanding on tegaserod mechanism of action, on its pharmacodynamics and pharmacokinetic properties, on safety and tolerability, with a summary of the key published clinical trials conducted in patients with irritable bowel syndrome (IBS). Its effects on colon inflammation have also been described.

Results: Tegaserod was withdrawn in 2007 due to increased risks of cardiovascular adverse effects. The manufacturer denied this, because pre-existing cardiovascular disease or risk factors were attributed to all affected patients. Thus, no causal relationship between tegaserod use and cardiovascular events was clearly shown. A matched case-control study of tegaserod-treated with untreated patients found no association between tegaserod and adverse cardiovascular outcomes. Despite its adverse effects, tegaserod resulted to be effective in treating chronic constipation in adult women aged < 65 years with IBS-C, while the safety and effectiveness of tegaserod in men with IBS-C have not been established.

Conclusion: Tegaserod was resubmitted to the Food and Drug Administration in 2018 for use in a low-risk population. Moreover, tegaserod has also been shown to improve symptoms, enhance gastric accommodation and significantly attenuate visceral pain arising from the colon in functional dyspepsia patients. Treatment with tegaserod seems also to exert a protective effect in inflamed colons, reducing the severity of colitis in animal models.

Targeting the 5-HT system: Potential side effects

Targeting the serotonin (5-HT) system is no simple task: there are at least 15 5-HT receptors, in addition to a number of transporters and metabolizing enzymes. Multiple 5-HT receptor variants exist due to genetic variations and/or post translational modifications, splice variants or editing variants. Some receptors may form homo and heteromers. The 5-HT system is targeted by multiple drugs to treat a variety of diseases. Given the homology amongst the 5-HT and neighbouring receptor classes, only few drugs are actually selective for a single target. In fact, many 5-HT drugs act on a combination of targets, i.e. several receptors and/or transporters or enzymes. For instance, a number of antidepressants or antipsychotics act on 5-HT and other transmitter systems. Recently developed drugs may show target selectivity by design, based on the current state of knowledge, whereas many older compounds hit multiple targets since they were developed using phenotypic screens, as was done well into the 1980's. Ergot analogues, antipsychotics or antidepressants, fall into this category. As our knowledge developed over the last 25-30 years, some targets have very well-defined liabilities: for instance, 5HT_2B or 5-HT_2A receptor agonists, will produce valvulopathies or hallucinations, respectively, whereas 5-HT₃ receptor antagonists, may lead to constipation. This short review will be limited in scope as there are multiple targets and even more compounds to discuss. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.

Gastrointestinal Disorders and Metabolic Syndrome: Dysbiosis as a Key Link and Common Bioactive Dietary Components Useful for their Treatment

Gastrointestinal (GI) diseases, which include gastrointestinal reflux disease, gastric ulceration, inflammatory bowel disease, and other functional GI disorders, have become prevalent in a large part of the world population. Metabolic syndrome (MS) is cluster of disorders including obesity, hyperglycemia, hyperlipidemia, and hypertension, and is associated with high rate of morbidity and mortality. Gut dysbiosis is one of the contributing factors to the pathogenesis of both GI disorder and MS, and restoration of normal flora can provide a potential protective approach in both these conditions. Bioactive dietary components are known to play a significant role in the maintenance of health and wellness, as they have the potential to modify risk factors for a large number of serious disorders. Different classes of functional dietary components, such as dietary fibers, probiotics, prebiotics, polyunsaturated fatty acids, polyphenols, and spices, possess positive impacts on human health and can be useful as alternative treatments for GI disorders and metabolic dysregulation, as they can modify the risk factors associated with these pathologies. Their regular intake in sufficient amounts also aids in the restoration of normal intestinal flora, resulting in positive regulation of insulin signaling, metabolic pathways and immune responses, and reduction of low-grade chronic inflammation. This review is designed to focus on the health benefits of bioactive dietary components, with the aim of preventing the development or halting the progression of GI disorders and MS through an improvement of the most important risk factors including gut dysbiosis.

A colon-specific prodrug of metoclopramide ameliorates colitis in an experimental rat model

Background

We examined whether metoclopramide (MCP), a modulator of dopamine and serotonin receptors, alleviated colitis and had synergistic effects when coadministered with 5-aminosalicylic acid (5-ASA) in an experimental model of colitis.

Methods

MCP azo-linked to 5-ASA (5-[4-chloro-2-{2-(diethylamino)ethylcarbamoyl}– 1-methoxyphenyl]azosalicylic acid, MCP-azo-ASA) was synthesized, where 5-ASA was used as a colon-targeting carrier and an anti-colitic agent, and the ability of MCP-azo-ASA to target the colon in vitro and in vivo was evaluated.

Results

Our results indicate that MCP-azo-ASA was cleaved to MCP and 5-ASA in the cecal contents, but not in the contents of the small intestine. Oral gavage with equimolar concentrations of MCP-azo-ASA and sulfasalazine (SSZ, a colon-specific prodrug of 5-ASA widely used clinically) demonstrated that the two prodrugs delivered comparable amounts of 5-ASA to the cecum. MCP was barely detected in the blood after oral gavage with MCP-azo-ASA. In a rat model of 2,4-dinitrobenzene sulfonic acid hydrate (DNBS)-induced colitis, MCP-azo-ASA alleviated colonic damage in a dose-dependent manner. Moreover, MCP-azo-ASA reduced the concentrations of inflammatory mediators in the inflamed colon. At low equimolar doses, MCP-azo-ASA, but not SSZ, resulted in significant anti-colitic effects, which indicates that MCP has anti-colitic activity. MCP-azo-ASA had anti-colitic effects equal to those of SSZ at high equimolar doses.

Conclusion

Thus, our results indicate that MCP-azo-ASA is a colon-specific prodrug of MCP. Targeted delivery of MCP to the colon ameliorated DNBS-induced colitis in rats, and we did not observe any synergistic effects of MCP after co-delivery with 5-ASA.

Recent insights into the role of ChREBP in intestinal fructose absorption and metabolism

Fructose in the form of sucrose and high fructose corn syrup is absorbed by the intestinal transporter and mainly metabolized in the small intestine. However, excess intake of fructose overwhelms the absorptive capacity of the small intestine, leading to fructose malabsorption. Carbohydrate response element-binding protein (ChREBP) is a basic helix-loop-helix leucine zipper transcription factor that plays a key role in glycolytic and lipogenic gene expression in response to carbohydrate consumption. While ChREBP was initially identified as a glucose-responsive factor in the liver, recent evidence suggests that ChREBP is essential for fructoseinduced lipogenesis and gluconeogenesis in the small intestine as well as in the liver. We recently identified that the loss of ChREBP leads to fructose intolerance via insufficient induction of genes involved in fructose transport and metabolism in the intestine. As fructose consumption is increasing and closely associated with metabolic and gastrointestinal diseases, a comprehensive understanding of cellular fructose sensing and metabolism via ChREBP may uncover new therapeutic opportunities. In this mini review, we briefly summarize recent progress in intestinal fructose metabolism, regulation and function of ChREBP by fructose, and delineate the potential mechanisms by which excessive fructose consumption may lead to irritable bowel syndrome.

Estrogen signaling deregulation related with local immune response modulation in irritable bowel syndrome

The etiology and pathogenesis underlying irritable bowel syndrome (IBS), a common gastrointestinal disorder are still unclear. Cumulating data suggest dysregulation of inflammatory and immune response pathways and changes of epithelial barrier function. The role of estrogens albeit varied, in responses of immune system is well documented. The aim of this study was to investigate estrogen receptors engagment in IBS subtypes, i.e. constipation predominant (IBS-C) and diarrhea predominant (IBS-D). Furthermore, we analyzed whether estrogen signaling is accompanied by alteration in expression of pro- and anti-inflammatory cytokines and microRNAs that can regulate among others genes involved in immune responses. It was found that estrogen receptor α (ERα) and G protein-coupled estrogen receptor (GPER) expression is up-regulated in IBS while estrogen receptor β (ERβ) appears to be down-regulated at mRNA but up-regulated at the protein level. When gender and female age were included statistically significant overexpression of ERα in IBS-D women under the age of 50, while of GPER in IBS-D men was stated. In all studied IBS samples disturbances in expression of cytokines IL-6, IL-10 and TNF-α as well as miR-145, miR-148-5p and miR-592 were observed. This research reveals the association of estrogen receptors with IBS. Simultaneous alterations of studied immunomodulatory cytokines and microRNAs suggest that in IBS dysregulation of local immune response may involve estrogen-dependent way.

Chronic abdominal pain in irritable bowel syndrome - current and future therapies

INTRODUCTION

Irritable bowel syndrome (IBS) is a functional gut disorder that typically manifests in early adult years. One of the two major symptoms of the disease is chronic, visceral pain. The patients report pain as the most distressing symptom with the greatest impact on quality of life, challenging both to patients and healthcare providers. Areas covered: This review focuses on the pathophysiology of abdominal pain in IBS and describes current treatment possibilities. It also covers latest findings that may lead to novel pharmacological options in IBS pain management. Expert commentary: Pain is the main contributor to severity in IBS. Seeking pain alleviation is the most common reason that IBS sufferers consult with their physicians. Not all patients report being satisfied with available treatments for pain in IBS and there is a pressing need to find new, more efficient therapies for this syndrome.

Therapeutic Effects of Low-dose Bismuth Subcitrate on Symptoms and Health-related Quality of Life in Adult Patients with Irritable Bowel Syndrome: A Clinical Trial

Objective:

Irritable bowel syndrome (IBS) is a chronic functional disorder of the gastrointestinal tract that causes abdominal pain or discomfort and alters bowel with no organic abnormalities. Treatment options for IBS have increased in number in the past decade, and clinicians should not be limited to use only conventional treatments to cure it. This article is a placebo-controlled clinical trial to assess the therapeutic effects of low-dose bismuth subcitrate on symptoms and the health-related quality of life in adult patients with IBS.

Methods:

This clinical trial was done during July 2015 to January 2016 in Isfahan, Iran. For each of three subtypes (IBS-constipation dominant, IBS-diarrhea dominant [IBS-D], and IBS-mixed), we included patients with IBS aged 18–70 years, diagnosed according to the Rome III criteria. In this study, 129 eligible patients were enrolled, of which 119 continued on the protocol to the end of study. They were allocated in placebo group (Group A) and intervention group (Group B). The medication for Group B was mebeverine and bismuth subcitrate and for Group A was mebeverine and placebo of bismuth subcitrate. Initially, the patients of both groups completed IBS-related questionnaires (IBS-quality of life, IBS-severity scoring system), then given drugs for a 4-week period (1^st on-drug period). Then, both groups were given only mebeverine hydrochloride 200 mg capsule for another 4 weeks (off-drug period). At last, Group A and Group B were given medication (2^nd on-drug period), the same as 1^st on-drug period.

Findings:

With respect to quality of life, the trend of IBS-QOL score changed significantly during the study period in both the intervention and placebo groups; however, no significant differences were observed between the two groups (P < 0.005). In subgroups analysis, quality of life significantly improved in IBS-D during the study from the first measurement to the end of study (P = 0.004). The trends of changes in the severity of pain during the study between the intervention and control group were significantly different (P = 0.018).

Conclusion:

According to our study, IBS-D patients' symptoms improved significantly with bismuth therapy. We found that adding low-dose bismuth to mebeverine in nonresponsive IBS patients in conventional treatment could be helpful.

Fecal microbiota transplantation for managing irritable bowel syndrome

Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11.2% of the world adult population. The intestinal microbiome is thought to play a pivotal role in the pathophysiology of IBS. The composition of the fecal microbiome in IBS patients differs from that in healthy individuals, but the exact bacteria species involved in the development of IBS remain to be determined. There is also an imbalance between useful and harmful bacteria (dysbiosis) in the intestinal microbiome in patients with IBS. Consuming prebiotics, probiotics, or synbiotics has a limited effect on IBS symptoms. In contrast, fecal microbiome transplantation (FMT) in IBS patients reverses the dysbiosis to normobiosis and reduces the IBS symptoms in about 70% of patients, and is not associated with any serious adverse events. Area covered: The available data on the microbiome and FMT in IBS regarding the efficacy of FMT in managing IBS were found using a PubMed search of these topics. Expert commentary: FMT is a promising tool for managing irritable syndrome. It appears to be effective, easy, and inexpensive procedure. However, more controlled studies involving larger cohorts of IBS are needed before FMT can be used as a routine procedure in the clinic.

Risk of Pancreatitis Following Treatment of Irritable Bowel Syndrome With Eluxadoline

BACKGROUND & AIMS

The Food and Drug Administration approved eluxadoline for the treatment of diarrhea-predominant irritable bowel syndrome despite cases of pancreatitis in early stage trials. We investigated the frequency of pancreatitis attributed to eluxadoline in postmarketing surveillance.

METHODS

We extracted reports on eluxadoline submitted to the Federal Adverse Event Reporting System from January through September 2016. We collected data on patient age and sex, event date, reporting entity (consumer, physician, pharmacist, legal worker, or other), medications, dosages, presumed role in the event (coinciding, primary, or secondary suspect), treatment indication, and outcome (death, life threatening, hospitalization, disability, or other).We compared data for eluxadoline with data from antidiarrheals, oxycodone, and rifaximin using the κ² test, Kruskal-Wallis rank test, and analysis of variance; findings with P < .05 were considered statistically significant.

RESULTS

Pancreatitis accounted for 16.4% of the 597 reports of adverse events linked to eluxadoline; 53 cases required hospitalization. Pancreatitis was listed as treatment complication of other agents in significantly lower proportions of cases (loperamide, 0.3%; diphenoxylate, 0.4%; oxycodone, 0.2%; rifaximin, 0.5%), with 75% of these submissions not considering the agent as causal.

CONCLUSIONS

In an analysis of reports on eluxadoline submitted to the Federal Adverse Event Reporting System, we confirmed a previously reported risk of pancreatitis associated with eluxadoline. The need for hospitalization in at least half of these instances and a recent report of 2 fatalities should prompt reassessments of the agent's risk-benefit ratio.

Effects of Noninvasive Skin Stimulation with Microcones on Constipation: A Double-Blinded Controlled Study

Objective: The use of noninvasive skin stimulation with microcones for constipation is promising. However, no double-blinded study has assessed the effects of this approach on constipation. The goal of this research was to assess the effects on constipation when using noninvasive skin stimulation with microcones. Materials and Methods: This double-blinded, controlled study included 44 subjects, each with a score of 5 points or higher on the Japanese version of the Constipation Assessment Scale (CAS-J). The subjects were randomly divided into 2 groups: (1) a stimulation group (skin-stimulation device with microcones; n = 23; group S) and (2) a placebo group (identical device without microcones; n = 21; group P). The subjects were required to attach the skin-stimulation devices to both cavum conchae with dedicated bandages every day for 2 months by themselves. Main Outcome Measures: This study assessed the severity of constipation, total mood disturbance (TMD) score, and salivary amylase activity (SAA) in each subject. Measurements were obtained before, during, and after the intervention. Results: With regard to the CAS-J score, significant differences were observed in both groups; however, no significant differences were observed between the groups. With regard to the TMD score, significant differences were observed in group S but not in group P. With regard to SAA, there were no significant differences in both groups; however, significant differences were noted after the intervention between the groups. Conclusions: Noninvasive skin stimulation with microcones could relieve constipation and improve TMD scores and SAA activity. This procedure may be used as a self-care option.

Food consumption and dietary intakes in 36,448 adults and their association with irritable bowel syndrome: Nutrinet-Santé study

INTRODUCTION

Diet plays an important role for patients with irritable bowel syndrome (IBS). The aim of this study was to compare the diets in terms of food consumption and nutrient intake between subjects with IBS and controls in a large French population.

METHODS

This study included 36,448 subjects from the Nutrinet-Santé cohort study, who completed a questionnaire pertaining to functional bowel disorders based on the Rome III criteria. Dietary data were obtained from at least three self-administered 24 h records via the internet. Association between IBS and diet was evaluated by comparison tests controlled for gender, age and total energy intake (ANCOVA tests).

RESULTS

Subjects included were mainly women (76.9%) and the mean age was 50.2 ± 14.2 years. Among these individuals, 1870 (5.1%) presented with IBS. Compared to healthy controls, they had significantly lower consumption of milk (74.6 versus 88.4 g/day; p < 0.0001), yogurt (108.4 versus 115.5 g/day; p = 0.001), fruits (192.3 versus 203.8 g/day; p < 0.001), and higher soft non-sugared beverages (1167.2 versus 1122.9 ml/day; p < 0.001). They had higher total energy intake (2028.9 versus 1995.7 kcal/day; p < 0.001), with higher intakes of lipids (38.5 versus 38.1% of total energy intake; p = 0.001) and lower intakes of proteins (16.4 versus 16.8% of total energy intake; p < 0.0001), as well as micronutrients (calcium, potassium, zinc and vitamins B2, B5 and B9, all p < 0.0001).

CONCLUSIONS

In this large sample, these findings suggest that dietary intake of subjects suffering from IBS differs from that of control subjects. They may have adapted their diet according to symptoms following medical or non-medical recommendations.

Ramosetron for the treatment of irritable bowel syndrome with diarrhea: a systematic review and meta-analysis of randomized controlled trials

Background

Ramosetron is a potent and selective serotonin type 3 receptor antagonist. This meta-analysis aimed to analyze the efficacy and safety of ramosetron for irritable bowel syndrome with diarrhea (IBS-D).

Methods

Pubmed, MEDLINE, EMBASE and the Cochrane Library were searched for randomized controlled trials investigating the efficacy and safety of ramosetron for IBS-D. Risk of bias was assessed as described in the Cochrane handbook. A random effects model was used to calculate the effects of ramosetron vs placebo on symptomatic improvements, including relief of overall IBS symptoms, relief of abdominal discomfort/pain, improvement in abnormal bowel habits, and improvement in stool consistency, expressed as pooled relative risks (RRs) with 95% confidence interval (CI). Adverse events data were also summarized with RRs.

Results

Four randomized controlled trials involving 1623 participants were included. Compared with placebo, ramosetron could lead to relief of overall IBS symptoms (RR 1.70; 95%CI 1.48, 1.95), relief of abdominal discomfort/pain (RR 1.41; 95%CI, 1.24, 1.59), improvement in abnormal bowel habits (RR 1.72; 95%CI, 1.50, 1.98) and improvement in stool consistency (RR 1.71; 95%CI 1.40, 2.08). Ramosetron could lead to relief of overall IBS symptoms in both male and female patients (RR; 95%CI: 1.94; 1.58, 2.38 and 1.49; 1.25, 1.79). The RR (95%CI) for reported adverse events of ramosetron vs placebo was 1.10 (0.97, 1.26) across all studies. No serious adverse events (e.g., ischemic colitis) were reported. The incidences of hard stool and constipation were higher in ramosetron group compared with placebo group (RR; 95%CI: 4.74; 3.00, 7.51 and 2.53; 1.57, 4.10, respectively).

Conclusions

Ramosetron had beneficial effects to both male and female IBS-D patients. Treatment with ramosetron could cause more hard stool and constipation, without severe adverse events.

Perioperative morbidity, bowel function and oncologic outcome after radical cystectomy and ileal orthotopic neobladder reconstruction: Studer-pouch versus I-pouch

OBJECTIVE

To investigate whether the length of ileum used for ileal orthotopic neobladder (ONB) reconstruction (60 cm vs. 40 cm) after radical cystectomy (RC) for bladder cancer (BC) impacts on bowel function, postoperative complications or survival outcome.

MATERIAL AND METHODS

In this retrospective study, we included 56 patients who received an ONB (Studer (S)-Pouch: 23 patients; I-Pouch: 33 patients) after RC for BC between 2003 and 2011. Preoperative comorbidities were assessed by the Charlson Comorbidity Index (CCI) and surgical complications as graded by the Clavien-Dindo classification. Changes of perioperative bowel habits were retrospectively evaluated by the validated Gastrointestinal Quality of Life Index (GIQLI). Kaplan-Meier analyses calculated survival outcomes between both ONB types.

RESULTS

Preoperative CCI was comparable between S- and I-pouch patients. No significant differences were observed for 30-day major- (p = 0.33) and minor (p = 0.96) complication rates between both neobladder types. S-Pouch patients reported higher preoperative stool frequencies (S-pouch: mean 2.7; I-pouch: mean 3.4; p = 0.049) and tended to suffer from urgency (S: mean 2.9; I: mean 3.4; p = 0.059). No significant differences in postoperative bowel disorders were found between both neobladder types (S-Pouch: 15.9, IQR; I-Pouch: 16.6 IQR; p = 0.84). Furthermore, we observed no overall-, cancer specific- or recurrence free survival advantage for either of both ONB variants (p = 0.81; 0.65 and 0.78), respectively.

CONCLUSION

Comorbidities, perioperative complication rates and bowel habits were similar between both ONB substitutes and did not influence survival outcomes. These stratified data suggest that the length of ileum used for ONB reconstruction (60- vs. 40 cm) does not impact per se on postoperative bowel function.

Dietary fiber in irritable bowel syndrome (Review)

Irritable bowel syndrome (IBS) is a common chronic gastrointestinal disorder. It is widely believed that IBS is caused by a deficient intake of dietary fiber, and most physicians recommend that patients with IBS increase their intake of dietary fiber in order to relieve their symptoms. However, different types of dietary fiber exhibit marked differences in physical and chemical properties, and the associated health benefits are specific for each fiber type. Short-chain soluble and highly fermentable dietary fiber, such as oligosaccharides results in rapid gas production that can cause abdominal pain/discomfort, abdominal bloating/distension and flatulence in patients with IBS. By contrast, long-chain, intermediate viscous, soluble and moderately fermentable dietary fiber, such as psyllium results in a low gas production and the absence of the symptoms related to excessive gas production. The effects of type of fiber have been documented in the management of IBS, and it is known to improve the overall symptoms in patients with IBS. Dietary fiber acts on the gastrointestinal tract through several mechanisms, including increased fecal mass with mechanical stimulation/irritation of the colonic mucosa with increasing secretion and peristalsis, and the actions of fermentation byproducts, particularly short-chain fatty acids, on the intestinal microbiota, immune system and the neuroendocrine system of the gastrointestinal tract. Fiber supplementation, particularly psyllium, is both safe and effective in improving IBS symptoms globally. Dietary fiber also has other health benefits, such as lowering blood cholesterol levels, improving glycemic control and body weight management.

Moxibustion treatment for diarrhea-predominant irritable bowel syndrome: study protocol for a randomized controlled trial

BACKGROUND

Irritable bowel syndrome (IBS) is a worldwide disease with high morbidity. The effect of current treatment with Western medicine is not satisfactory. Although moxibustion treatment is widely used for gastrointestinal diseases, randomized controlled trials on the use of this treatment for IBS are limited. This study aims to evaluate the clinical efficacy and safety of moxibustion treatment in patients with diarrhea-predominant irritable bowel syndrome (IBS-D).

METHODS/DESIGN

A multi-center, randomized, single-blind and placebo-controlled trial is employed. 104 cases will be divided into two groups: (1) a mild-warm moxibustion group in which moxa stick is 3-5 cm away from acupuncture points and the skin temperature is maintained at 43 ± 1 °C; and (2) a placebo moxibustion group in which moxa stick is 8-10 cm away from acupuncture points and the skin temperature is maintained at 37 ± 1 °C. Moxibustion is performed on bilateral ST25 and ST36 in the two groups for 30 min each time, three times a week for 6 weeks. The patients are followed up at the 12th and 18th weeks. Adequate relief is used as a primary outcome measure; IBS symptom severity score, Bristol stool form scale, IBS quality-of-life questionnaire, and hospital anxiety and depression scale are used as secondary outcome measures.

DISCUSSION

This study aims to demonstrate the safety and efficacy of moxibustion treatment for IBS-D, which may validate moxibustion as an effective therapy for treating IBS-D.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT02421627 (8 April 2015).

Efficacy of the low FODMAP diet for treating irritable bowel syndrome: the evidence to date

This review summarizes the published clinical studies concerning the management of irritable bowel syndrome (IBS) using restriction of Fermentable Oligosaccharide, Disaccharide, Monosaccharide, and Polyols in the diet (low FODMAP diet). In recent years, the data supporting low FODMAP diet for the management of IBS symptoms have emerged, including several randomized controlled trials, case-control studies, and other observational studies. Unlike most dietary manipulations tried in the past to alleviate gastrointestinal symptoms of IBS, all studies on low FODMAP diet have consistently shown symptomatic benefits in the majority of patients with IBS. However, dietary adherence by the patients and clear dietary intervention led by specialized dietitians appear to be vital for the success of the diet. Up to 86% of patients with IBS find improvement in overall gastrointestinal symptoms as well as individual symptoms such as abdominal pain, bloating, constipation, diarrhea, abdominal distention, and flatulence following the diet. FODMAP restriction reduces the osmotic load and gas production in the distal small bowel and the proximal colon, providing symptomatic relief in patients with IBS. Long-term health effects of a low FODMAP diet are not known; however, stringent FODMAP restriction is not recommended owing to risks of inadequate nutrient intake and potential adverse effects from altered gut microbiota. In conclusion, the evidence to date strongly supports the efficacy of a low FODMAP diet in the treatment of IBS. Further studies are required to understand any potential adverse effects of long-term restriction of FODMAPs.

The signaling of amitriptyline-induced inhibitory effect on electrical field stimulation response in colon smooth muscle

Amitriptyline, a well-known antidepressant, exerts inhibitory effect on electrically stimulated rat colon smooth muscle contraction. In this study, we investigated the signaling pathway of amitriptyline-induced inhibitory effect. Changes in isometric force of colon muscle were recorded on polygraph, and data were analyzed by measuring the inhibitory extent induced by amitriptyline. Firstly, muscles were contracted by stimulation with electric field stimulation (EFS), and then, amitriptyline was added cumulatively to determine its influence effect on EFS. Amitriptyline significantly inhibited EFS-induced contraction dose dependently. Then, the mechanism of inhibitory effect of amitriptyline was evaluated by pretreating with various antagonists such as L-NAME, methylene blue, atropine, 5-HT receptors blockers, guanethidine, prazosin, guanabenz, isoprenaline, Y27632 (Rho-kinase inhibitor), ML9 (myosin light chain kinase (MLCK) inhibitor), U73122 (PLC inhibitor), and chelerythrine (PKC inhibitor). Then, Ca(2+) channel blocker (nifedipine) and K(+)channel blockers, tetraethylammonium (TEA), 4-aminopyridine (4-AP), and glybenclamide, were used to determine the involvement of ion channels. L-NAME, guanabenz, 5HT4 receptor blocker, ML9, and Y27632 enhanced the effect of amitriptyline. Meanwhile, methylene blue, atropine, guanethidine, prazosin, methylsergide, ondansetron, U73122, and chelerythrine blocked its effect. It was also shown that nifedipine enhanced but TEA and glybenclamide blocked amitriptyline-induced inhibitory effect on EFS. Our results indicated that amitriptyline may exert inhibitory effect in response to EFS by inhibiting muscarinic receptors and then PLC-mediated PKC pathway leading to opening of ATP-sensitive potassium channel.

Electroacupuncture versus Moxibustion for Irritable Bowel Syndrome: A Randomized, Parallel-Controlled Trial

Objective. To compare the impacts of electroacupuncture (EA) and mild moxibustion (Mox) on patients with irritable bowel syndrome (IBS). Method. Eighty-two IBS patients were randomly allocated into EA group (n = 41) and Mox group (n = 41) and received corresponding interventions for four weeks. Before and after the treatment, the Visual Analogue Scale for Irritable Bowel Syndrome (VAS-IBS) was used to evaluate the gastrointestinal symptoms and mental well-being; and the expression of serotonin (5-hydroxytryptamine, 5-HT), 5-HT₃ receptor (5-HT₃R), and 5-HT₄ receptor (5-HT₄R) in sigmoid mucosal tissue were detected. Results. Both EA and Mox can radically improve the total VAS-IBS score (P < 0.05), and EA was found to be more effective in ameliorating the symptom of constipation, while Mox was found to be more effective in ameliorating the symptom of diarrhoea. The abnormal expressions of 5-HT, 5-HT₃R, and 5-HT₄R in both groups were significantly improved after the treatments (all P < 0.05), and EA was superior to Mox in regulating the abnormally decreased 5-HT₄R expression in IBS patients with constipation (P < 0.05). Conclusion. Electroacupuncture and mild moxibustion were both effective in improving IBS symptoms and modulate abnormal expressions of 5-HT, 5-HT₃R, and 5-HT₄R in the colonic tissue.

The role of cannabinoids in regulation of nausea and vomiting, and visceral pain

Marijuana derived from the plant Cannabis sativa has been used for the treatment of many gastrointestinal (GI) disorders, including anorexia, emesis, abdominal pain, diarrhea, and others. However, its psychotropic side effects have often limited its use. Several cannabinoid receptors, which include the cannabinoid receptor 1 (CB1), CB2, and possibly GPR55, have been identified throughout the GI tract. These receptors may play a role in the regulation of food intake, nausea and emesis, gastric secretion and gastroprotection, GI motility, ion transport, visceral sensation, intestinal inflammation, and cell proliferation in the gut. However, the regulation of nausea and vomiting by cannabinoids and the endocannabinoid system has shed new knowledge in this field. Thus far, despite evidence of visceral sensitivity inhibition in animal models, data in irritable bowel syndrome (IBS) patients is scarce and not supportive. Furthermore, many compounds that either act directly at the receptor or increase (or reduce) ligand availability have the potential to affect other brain functions and cause side effects. Novel drug targets such as FAAH and monoacylglycerol lipase (MAGL) inhibitors appear to be promising in animal models, but more studies are necessary to prove their efficiency. The promise of emerging drugs that are more selective and peripherally acting suggest that, in the near future, cannabinoids will play a major role in managing an array of GI diseases.

Prebiotics and probiotics in irritable bowel syndrome and inflammatory bowel disease in children

Underlying pathophysiological mechanisms of irritable bowel syndrome (IBS), a common disorder characterized by abdominal pain associated to a change in stool consistency or frequency, include low-grade inflammation and intestinal microbiota changes. Few and disappointing data are available for prebiotics. A few controlled trials (RCTs) of probiotics are instead available with favourable effects, although most are limited by suboptimal design and small sample size. A recent report from the Rome foundation group included 32 RCTs of probiotics, most of which showed an overall modest improvement in symptoms, with the patients most benefitting from probiotics being those with predominant diarrhoea and those having a post-infectious IBS. A review focusing only on children with functional gastrointestinal disorders concluded that probiotics are more effective than placebo in the treatment of patients with abdominal pain-related functional gastrointestinal disorders, although no effect on constipation was evident. The role for probiotics in inflammatory bowel disease (IBD) appears logical: the endogenous intestinal microbiota plays a central role in their development, and various probiotics have been found effective in animal models of IBD. However, research in humans has been overall quite limited, and it would seem that after a phase of intense research in the first decade of this century, the pace has slowed down, with fewer clinical trials been published in the past 2-3 years. To summarize current evidence: no probiotic has proven successful in Crohn's disease. In ulcerative colitis, on the other hand, data are more promising, and a very recent meta-analysis, that included 23 randomized controlled trials, concluded that there is evidence of efficacy for the probiotic mixture VSL#3 in helping inducing and maintaining remission, as well as in maintaining remission in patients with pouchitis. It is fair to state that for both IBD and IBS, more well-designed, rigorous, randomized clinical trials must be performed.

Therapeutic effects of Lactobacillus in treating irritable bowel syndrome: a meta-analysis

OBJECTIVE

As the lack of reliable treatment for irritable bowel syndrome (IBS) prompts interest in the development of new therapies, we aimed to systematically evaluate the effect of Lactobacillus in treating this disease.

METHODS

We searched MEDLIINE, PubMed, Scopus, Web of Science and the Cochrane Central Register of Controlled Trials for the period from 1966 to August 2013 for double-blind, placebo-controlled trials investigating the efficacy of Lactobacillus treatment in the management of IBS. The studies were screened for inclusion based on randomization, controls and reported measurable outcomes. We used the Jadad score to assess the quality of the articles. The STATA 11.0 and Revman 5.0 software packages were used for the meta-analysis. The STATA 11.0 software program was also used to assess indicators of publication bias according to Begg's and Egger's tests.

RESULTS

Six randomized, placebo-controlled clinical trials met the criteria and were included in the meta-analysis. The Jadad score of the articles was >3, and three articles were of high quality. We analyzed the heterogeneity of the studies and found no heterogeneity in the meta-analysis. In the forest plot, the diamond was on the right side of the vertical line and did not intersect with the line. The pooled relative risk for clinical improvement with Lactobacillus treatment was 7.69 (95% confidence interval: 2.33-25.43, p=0.0008). For adults, the pooled relative risk for clinical improvement with Lactobacillus treatment was 17.62 (95% confidence interval: 5.12-60.65, p<0.00001). For children, the pooled relative risk for clinical improvement with Lactobacillus treatment was 3.71 (95% confidence interval:1.05-13.11, p=0.04). Using the STATA 10.0 and Revman 5.0 software programs, we confirmed that Lactobacillus exhibited significant efficacy in treating IBS.

CONCLUSION

Compared with the placebo, Lactobacillus treatment was found to be associated with a significantly higher rate of treatment responders in the overall population with IBS, without any side effects. As to limitations of the analysis, additional research is needed.

The mind-body connection in irritable bowel syndrome: A randomised controlled trial of hypnotherapy as a treatment

BACKGROUND

Hypnotherapy has been reported as being beneficial in the treatment of irritable bowel syndrome (IBS). We aimed to test the hypothesis that patients with IBS treated 'holistically' by hypnosis (i.e. by combined psychological and physiological symptom imagery) would have greater improvement in their IBS symptoms than patients treated by hypnosis using standard 'gut-directed' hypnotherapy, and both would be superior to simple relaxation therapy.

METHODS

Patients (n = 51) with Rome II criteria were randomised to 'individualised' (holistic) hypnotherapy, standard 'gut-directed' hypnotherapy or relaxation therapy for a period of 11 weeks with two follow-up assessments at 2 weeks and at 3 months after the completion of the trial. The primary outcome was bowel symptom severity scale (BSSS).

RESULTS

All the participants in this study improved their IBS symptoms (pain, bloating, constipation and diarrhoea) and physical functioning at the end of the treatment from baseline, but this was not significantly different across the treatment arms.

CONCLUSION

Neither 'individualised' nor 'gut-directed' hypnotherapy is superior to relaxation therapy in IBS.

Brain and gut interactions in irritable bowel syndrome: new paradigms and new understandings

Irritable bowel syndrome (IBS) is characterized by abdominal pain and altered bowel habits. Visceral hypersensitivity is believed to be a key underlying mechanism that causes pain. There is evidence that interactions within the brain and gut axis (BGA), that involves both the afferent-ascending and the efferent-descending pathways, as well as the somatosensory cortex, insula, amygdala, anterior cingulate cortex, and hippocampus, are deranged in IBS showing both the activation and inactivation. Clinical manifestations of IBS such as pain, altered gut motility, and psychological dysfunction may each be explained, in part, through the changes in the BGA, but there is conflicting information, and its precise role is not fully understood. A better understanding of the BGA may shed more knowledge regarding the pathophysiology of IBS that in turn may lead to the discovery of novel therapies for this common disorder.

Irritable bowel syndrome is positively related to metabolic syndrome: a population-based cross-sectional study

Irritable bowel syndrome is a common gastrointestinal disorder that may affect dietary pattern, food digestion, and nutrient absorption. The nutrition-related factors are closely related to metabolic syndrome, implying that irritable bowel syndrome may be a potential risk factor for metabolic syndrome. However, few epidemiological studies are available which are related to this potential link. The purpose of this study is to determine whether irritable bowel syndrome is related to metabolic syndrome among middle-aged people. We designed a cross-sectional study of 1,096 subjects to evaluate the relationship between irritable bowel syndrome and metabolic syndrome and its components. Diagnosis of irritable bowel syndrome was based on the Japanese version of the Rome III Questionnaire. Metabolic syndrome was defined according to the criteria of the American Heart Association scientific statements of 2009. Dietary consumption was assessed via a validated food frequency questionnaire. Principal-components analysis was used to derive 3 major dietary patterns: “Japanese”, “sweets-fruits”, and “Izakaya (Japanese Pub) “from 39 food groups. The prevalence of irritable bowel syndrome and metabolic syndrome were 19.4% and 14.6%, respectively. No significant relationship was found between the dietary pattern factor score tertiles and irritable bowel syndrome. After adjustment for potential confounders (including dietary pattern), the odds ratio (95% confidence interval) of having metabolic syndrome and elevated triglycerides for subjects with irritable bowel syndrome as compared with non-irritable bowel syndrome are 2.01(1.13–3.55) and 1.50(1.03–2.18), respectively. Irritable bowel syndrome is significantly related to metabolic syndrome and it components. This study is the first to show that irritable bowel syndrome was significantly related to a higher prevalence of metabolic syndrome and elevated triglycerides among an adult population. The findings suggest that the treatment of irritable bowel syndrome may be a potentially beneficial factor for the prevention of metabolic syndrome. Further study is needed to clarify this association.

Are probiotics or prebiotics useful in pediatric irritable bowel syndrome or inflammatory bowel disease?

Treatment options for irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are notoriously either inadequate (IBS) or loaded with potentially serious side effects and risks (IBD). In recent years, a growing interest in effective and safer alternatives has focused on the potential role of probiotics and their metabolic substrates, prebiotics. It is in fact conceivable that the microbiome might be targeted by providing the metabolic fuel needed for the growth and expansion of beneficial microorganisms (prebiotics) or by administering to the host such microorganisms (probiotics). This review presents a concise update on currently available data, with a special emphasis on children. Data for prebiotics in IBS are scarce. Low doses have shown a beneficial effect, while high doses are counterproductive. On the contrary, several controlled trials of probiotics have yielded encouraging results. A meta-analysis including nine randomized clinical trials in children showed an improvement in abdominal pain for Lactobacillus GG, Lactobacillus reuteri DSM 17938, and the probiotic mixture VSL#3. The patients most benefiting from probiotics were those with predominant diarrhea or with a post-infectious IBS. In IBD, the use of prebiotics has been tested only rarely and in small scale clinical trials, with mixed results. As for probiotics, data in humans from about three dozens clinical trials offer mixed outcomes. So far, none of the tested probiotics has proven successful in Crohn’s disease, while in ulcerative colitis a recent meta-analysis on 12 clinical trials (1 of them in children) showed efficacy for the probiotic mixture VSL#3 in contributing to induce and to maintain remission. It is evident that this is a rapidly evolving and promising field; more data are very likely to yield a better understanding on what strains should be used in different specific clinical settings and in what doses.

On-demand treatment with alverine citrate/simeticone compared with standard treatments for irritable bowel syndrome: results of a randomised pragmatic study

BACKGROUND

In routine practice, irritable bowel syndrome (IBS) symptoms are often difficult to be relieved and impair significantly patients' quality of life (QoL). A randomised, double-blind, placebo-controlled study has shown the efficacy of alverine citrate/simeticone (ACS) combination for IBS symptom relief.

AIM

As IBS symptoms are often intermittent, this pragmatic study was designed to compare the efficacy of an on-demand ACS treatment vs. that of usual treatments.

METHODS

Rome III IBS patients were enrolled by 87 general practitioners who were randomly allocated to one of two therapeutic strategies: on-demand ACS or usual treatment chosen by the physician. The primary outcome measure was the improvement of the IBSQoL score between inclusion and month 6.

RESULTS

A total of 436 patients (mean age: 54.4 years; women: 73.4%) were included, 222 in the ACS arm and 214 patients in the usual treatment arm, which was mainly antispasmodics. At 6 months, improvement of IBSQoL was greater with ACS than with the usual treatment group (13.8 vs. 8.4; p < 0.0008). The IBS-severity symptom score (IBS-SSS) was lower with ACS than in the usual treatment arm with a mean (SE) decrease of 170.0 (6.6) vs. 110.7 (6.7), respectively (p = 0.0001). An IBS-SSS < 75 was more frequent in the ACS group (37.7% vs. 16.0%; p < 0.0001). Improvement of both abdominal pain and bloating severity was also greater with the on-demand ACS treatment, which was associated with both lower direct and indirect costs.

CONCLUSIONS

After 6 months, on-demand ACS treatment led to a greater improvement of QoL, reduced the burden of the disease and was more effective for IBS symptom relief than usual treatments.

Neuroanatomy of lower gastrointestinal pain disorders

Chronic abdominal pain accompanying intestinal inflammation emerges from the hyperresponsiveness of neuronal, immune and endocrine signaling pathways within the intestines, the peripheral and the central nervous system. In this article we review how the sensory nerve information from the healthy and the hypersensitive bowel is encoded and conveyed to the brain. The gut milieu is continuously monitored by intrinsic enteric afferents, and an extrinsic nervous network comprising vagal, pelvic and splanchnic afferents. The extrinsic afferents convey gut stimuli to second order neurons within the superficial spinal cord layers. These neurons cross the white commissure and ascend in the anterolateral quadrant and in the ipsilateral dorsal column of the dorsal horn to higher brain centers, mostly subserving regulatory functions. Within the supraspinal regions and the brainstem, pathways descend to modulate the sensory input. Because of this multiple level control, only a small proportion of gut signals actually reaches the level of consciousness to induce sensation or pain. In inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) patients, however, long-term neuroplastic changes have occurred in the brain-gut axis which results in chronic abdominal pain. This sensitization may be driven on the one hand by peripheral mechanisms within the intestinal wall which encompasses an interplay between immunocytes, enterochromaffin cells, resident macrophages, neurons and smooth muscles. On the other hand, neuronal synaptic changes along with increased neurotransmitter release in the spinal cord and brain leads to a state of central wind-up. Also life factors such as but not limited to inflammation and stress contribute to hypersensitivity. All together, the degree to which each of these mechanisms contribute to hypersensitivity in IBD and IBS might be disease- and even patient-dependent. Mapping of sensitization throughout animal and human studies may significantly improve our understanding of sensitization in IBD and IBS. On the long run, this knowledge can be put forward in potential therapeutic targets for abdominal pain in these conditions.

Irritable bowel syndrome and migraine: bystanders or partners?

Irritable bowel syndrome (IBS) and migraine are distinct clinical disorders. Apart from the characteristics of chronic and recurrent pain in nature, these pain-related disorders apparently share many similarities. For example, IBS is female predominant with community prevalence about 5-10%, whereas that of migraine is 1-3% also showing female predominance. They are often associated with many somatic and psychiatric comorbidities in terms of fibromyaglia, chronic fatigue syndrome, interstitial cystitis, insomnia and depression etc., even the IBS subjects may have coexisted migraine with an estimated odds ratio of 2.66. They similarly reduce the quality of life of victims leading to the social, medical and economic burdens. Their pathogeneses have been somewhat addressed in relation to biopsychosocial dysfunction, heredity, genetic polymorphism, central/visceral hypersensitivity, somatic/cutaneous allodynia, neurolimbic pain network, gonadal hormones and abuses etc. Both disorders are diagnosed according to the symptomatically based criteria. Multidisciplinary managements such as receptor target new drugs, melantonin, antispasmodics, and psychological drugs and measures, complementary and alternatives etc. are recommended to treat them although the used agents may not be necessarily the same. Finally, the prognosis of IBS is pretty good, whereas that of migraine is less fair since suicide attempt and stroke are at risk. In conclusion, both distinct chronic pain disorders to share many similarities among various aspects probably suggest that they may locate within the same spectrum of a pain-centered disorder such as central sensitization syndromes. The true pathogenesis to involve these disorders remains to be clarified in the future.

Structure activity relationship of synaptic and junctional neurotransmission

Chemical neurotransmission may include transmission to local or remote sites. Locally, contact between 'bare' portions of the bulbous nerve terminal termed a varicosity and the effector cell may be in the form of either synapse or non-synaptic contact. Traditionally, all local transmissions between nerves and effector cells are considered synaptic in nature. This is particularly true for communication between neurons. However, communication between nerves and other effectors such as smooth muscles has been described as nonsynaptic or junctional in nature. Nonsynaptic neurotransmission is now also increasingly recognized in the CNS. This review focuses on the relationship between structure and function that orchestrate synaptic and junctional neurotransmissions. A synapse is a specialized focal contact between the presynaptic active zone capable of ultrafast release of soluble transmitters and the postsynaptic density that cluster ionotropic receptors. The presynaptic and the postsynaptic areas are separated by the 'closed' synaptic cavity. The physiological hallmark of the synapse is ultrafast postsynaptic potentials lasting milliseconds. In contrast, junctions are juxtapositions of nerve terminals and the effector cells without clear synaptic specializations and the junctional space is 'open' to the extracellular space. Based on the nature of the transmitters, postjunctional receptors and their separation from the release sites, the junctions can be divided into 'close' and 'wide' junctions. Functionally, the 'close' and the 'wide' junctions can be distinguished by postjunctional potentials lasting ~1s and tens of seconds, respectively. Both synaptic and junctional communications are common between neurons; however, junctional transmission is the rule at many neuro-non-neural effectors.

Fiber and functional gastrointestinal disorders

Despite years of advising patients to alter their dietary and supplementary fiber intake, the evidence surrounding the use of fiber for functional bowel disease is limited. This paper outlines the organization of fiber types and highlights the importance of assessing the fermentation characteristics of each fiber type when choosing a suitable strategy for patients. Fiber undergoes partial or total fermentation in the distal small bowel and colon leading to the production of short-chain fatty acids and gas, thereby affecting gastrointestinal function and sensation. When fiber is recommended for functional bowel disease, use of a soluble supplement such as ispaghula/psyllium is best supported by the available evidence. Even when used judiciously, fiber can exacerbate abdominal distension, flatulence, constipation, and diarrhea.

A meta-analysis of the therapeutic effects of amitriptyline for treating irritable bowel syndrome

OBJECTIVE

We aimed to evaluate the efficacy of amitriptyline as a therapeutic option for irritable bowel syndrome (IBS) through a meta-analysis of randomized controlled trials.

METHODS

For the years from 1966 until May 2012, PubMed, Scopus, Web of Science and the Cochrane Central Register of Controlled Trials were searched for double-blind, placebo-controlled trials investigating the efficacy of amitriptyline in the management of IBS.

RESULTS

Four randomized, placebo-controlled clinical trials met our criteria and were included in the meta-analysis. The pooled relative risk for clinical improvement with amitriptyline therapy was 4.18 (95% CI: 2.00 to 8.77, p=0.0001).

CONCLUSION

It was thus concluded that amitriptyline exhibits a clinically and statistically significant control of IBS symptoms.

In Vivo and In Vitro Antinociceptive Effect of Fagopyrum cymosum (Trev.) Meisn Extracts: A Possible Action by Recovering Intestinal Barrier Dysfunction

Fagopyrum cymosum (Trev.) Meisn (Fag) is a herb rhizome which has been widely used to treat diseases. To investigate the effects and mechanisms of the Fag on irritable bowel syndrome (IBS), in vivo neonatal pups maternal separation (NMS) combined with intracolonic infusion of acetic acid (AA) was employed to establish IBS rat models. Fag reduced their visceral hyperalgesia and the whole gut permeability, ameliorated colonic mucosa inflammation and injury, and upregulated the expression of decreased tight junction proteins (TJs) of claudin-1, occludin, and ZO-1 (except ZO-2) in colonic epithelium. Caco-2 monolayer cells were incubated with TNF-α and IFN-γ   in vitro to establish an epithelial barrier dysfunction model whose transepithelial electrical resistance (TER) depended more on dose of Fag than that of the controls, and whose TJs levels were lower than those of the controls. Fag upregulated the NP-40 insoluble and soluble components of the four TJs markedly in a dose-dependent manner. These data suggest that Fag alleviated the hyperalgesia of IBS rats by reducing intestinal inflammation and enhancing mucosal epithelial function after regulating the structure and function of TJs.

Effect of composite yogurt enriched with acacia fiber and Bifidobacterium lactis

AIM: To investigate whether composite yogurt with acacia dietary fiber and Bifidobacterium lactis (B. lactis) has additive effects in irritable bowel syndrome (IBS).

METHODS: A total of 130 patients were randomly allocated to consume, twice daily for 8 wk, either the composite yogurt or the control product. The composite yogurt contained acacia dietary fiber and high-dose B. lactis together with two classic yogurt starter cultures. Patients were evaluated using the visual analog scale via a structured questionnaire administered at baseline and after treatment.

RESULTS: Improvements in bowel habit satisfaction and overall IBS symptoms from baseline were significantly higher in the test group than in the control group (27.16 vs 15.51, P = 0.010, 64.2 ± 17.0 vs 50.4 ± 20.5, P < 0.001; respectively). In constipation-predominant IBS, improvement in overall IBS symptoms was significantly higher in the test group than in the control group (72.4 ± 18.4 vs 50.0 ± 21.8, P < 0.001). In patients with diarrhea-predominant IBS, improvement in bowel habit satisfaction from baseline was significantly higher in the test group than in the control group (32.90 vs 7.81, P = 0.006).

CONCLUSION: Our data suggest that composite yogurt enriched with acacia fiber and B. lactis has greater therapeutic effects in patients with IBS than standard yogurt.

Mucosal immune cell numbers and visceral sensitivity in patients with irritable bowel syndrome: is there any relationship?

OBJECTIVES

Repeated exposure to stress leads to mast cell degranulation, microscopic inflammation, and subsequent visceral hypersensitivity in animal models. To what extent this pathophysiological pathway has a role in patients with the irritable bowel syndrome (IBS) has not been properly investigated. The objective of this study was to assess the relationship between visceral hypersensitivity, microscopic inflammation, and the stress response in IBS.

METHODS

Microscopic inflammation of the colonic mucosa was evaluated by immunohistochemistry in 66 IBS patients and 20 healthy volunteers (HV). Rectal sensitivity was assessed by a barostat study using an intermittent pressure-controlled distension protocol. Salivary cortisol to a psychological stress was measured to assess the stress response.

RESULTS

Compared with HV, mast cells, T cells, and macrophages were decreased in IBS patients. Similarly, λ-free light chain (FLC)-positive mast cells were decreased but not immunoglobulin E (IgE)- and IgG-positive mast cells. There were no differences between hypersensitive and normosensitive IBS patients. No relation was found between any of the immune cells studied and the thresholds of discomfort, urge, first sensation, or IBS symptoms (e.g., abdominal pain, stool-related complaints, bloating). Finally, stress-related symptoms and the hypothalamic-pituitary-adrenal-axis response to stress were not correlated with the number of mast cells or the presence of visceral hypersensitivity.

CONCLUSIONS

Although the number of mast cells, macrophages, T cells, and λFLC-positive mast cells is decreased in IBS compared with HV, this is not associated with the presence of visceral hypersensitivity or abnormal stress response. Our data question the role of microscopic inflammation as an underlying mechanism of visceral hypersensitivity, but rather suggest dysregulation of the mucosal immune system in IBS.

A double-blind placebo-controlled trial to study therapeutic effects of probiotic Escherichia coli Nissle 1917 in subgroups of patients with irritable bowel syndrome

PURPOSE

To study the therapeutic effects of probiotic Escherichia coli Nissle 1917 (EcN) in irritable bowel syndrome (IBS) and identify subgroups benefiting most.

BACKGROUND

Some trials investigating therapeutic effects in irritable bowel syndrome have shown benefits in IBS subgroups only. Probiotic treatment seems to be promising.

METHODS

Patients with irritable bowel syndrome (120; Rome II) were recruited to a prospective double-blind study and randomized to either EcN (n = 60) or placebo (n = 60) given for 12 weeks. Objectives were to describe efficacy and safety of EcN in different groups of irritable bowel syndrome. Outcome was assessed by 'Integrative Medicine Patient Satisfaction Scale'.

RESULTS

Altogether, the responder rate was higher in the EcN than in the placebo group. However, only after 10 and 11 weeks, the differences were significant (Δ 20.0% points [95% CI 2.6; 37.4], p = 0.01 and Δ 18.3% points [95% CI 1.0; 35.7], p = 0.02, respectively). The best response was observed in the subgroup of patients with gastroenteritis or antibiotics prior to irritable bowel syndrome onset (Δ 45.7% points, p = 0.029). No significant differences were observed in any other subgroup. Both treatment groups showed similar adverse events and tolerance.

CONCLUSIONS

Probiotic EcN shows effects in irritable bowel syndrome, especially in patients with altered enteric microflora, e.g. after gastroenterocolitis or administration of antibiotics.

The efficacy and safety of rifaximin for the irritable bowel syndrome: a systematic review and meta-analysis

OBJECTIVES

Irritable bowel syndrome (IBS) affects 10-15% of the population, and treatment options are limited. Rifaximin is a minimally absorbed antibiotic that has shown efficacy in IBS patients. The objective of our study was to perform a meta-analysis and systematic review of available randomized, placebo controlled trials evaluating the efficacy and tolerability of rifaximin in patients with IBS.

METHODS

We performed a systematic literature search of multiple online electronic databases regardless of language. Inclusion criteria entailed randomized, placebo controlled trials and IBS defined by accepted symptom-based criteria. Meta-analysis was conducted to evaluate the summary odds ratios (ORs) and 95% confidence intervals (CIs) of combined studies for the primary and secondary outcomes using a random-effects model based on the DerSimonian and Laird method to reflect both within- and between study variability. We assessed heterogeneity using χ(2) test and the inconsistency index statistic (I(2)). Significant heterogeneity was defined as I(2) ≥25%. Meta-regression was performed using generalized linear mixed-effects model and study as random effects to estimate the summary OR adjusting for covariate differences across studies and treatment group. Publication bias was assessed by funnel plot analysis.

RESULTS

Systematic review identified 13,700 citations. Eighteen were deemed to be potentially relevant, of which five articles met eligibility. Meta-analysis found rifaximin to be more efficacious than placebo for global IBS symptom improvement (OR=1.57; 95% CI=1.22, 2.01; therapeutic gain=9.8%; number needed to treat (NNT)=10.2), with mild heterogeneity (P=0.25, I(2)=26%). For the key secondary outcome of bloating, raw data were available for four studies. Rifaximin was significantly more likely to improve bloating than placebo (OR=1.55; 95% CI=1.23-1.96; therapeutic gain=9.9%; NNT=10.1), with no significant heterogeneity (P=0.27, I(2)=23%). We found that studies with older patients and more females demonstrated higher response rates, which was consistent regardless of treatment group. In addition, studies with higher cumulative dose tended to report a higher response rate. Of the covariates evaluated, we found age to be most predictive of response, with a correlation coefficient of 0.97 between aggregate response rate and mean age in the placebo groups. Although studies with higher cumulative dose tended to show increased response rates, this was also seen consistently in both the treated and placebo groups. Adverse effects were similar among patients receiving rifaximin or placebo in all studies. The most common adverse events (AEs) (≤10%) with rifaximin were headache, upper respiratory infection, nausea, nasopharygitis, diarrhea, and abdominal pain. Serious AEs were rare (<1%) and similar with rifaximin and placebo.

CONCLUSIONS

Rifaximin proved more effective than placebo for global symptoms and bloating in IBS patients. The modest therapeutic gain was similar to that yielded by other currently available therapies for IBS. AEs were similar between rifaximin and placebo.

Gut memories: towards a cognitive neurobiology of irritable bowel syndrome

The brain and the gut are engaged in continual crosstalk along a number of pathways collectively termed the 'brain-gut axis'. Over recent years it has become increasingly clear that dysregulation of the axis at a number of levels can result in disorders such as irritable bowel syndrome (IBS). With recent advances in neuroimaging technologies, insights into the neurobiology of IBS are beginning to emerge. However the cognitive neurobiology of IBS has remained relatively unexplored to date. In this review we summarise the available data on cognitive function in IBS. Moreover, we specifically address three key pathophysiological factors, namely; stress, immune activation and chronic pain, together with other factors involved in the manifestation of IBS, and explore how each of these components may impact centrally, what neurobiological mechanisms might be involved, and consider the implications for cognitive functioning in IBS. We conclude that each factor addressed could significantly impinge on central nervous system function, supporting the view that future research efforts must be directed towards a detailed assessment of cognitive function in IBS.