Randomised controlled trial of mesalazine in IBS

Randomized double-blind placebo-controlled study to evaluate the effect of long-acting mesalamine on postinfectious irritable bowel syndrome with diarrhea

BACKGROUND

A subset of patients with irritable bowel syndrome (IBS) develop their symptoms after gastroenteritis, referred to as postinfectious IBS (PI-IBS). PI-IBS is associated with low-grade intestinal inflammation. Previous studies have evaluated mesalamine, an anti-inflammatory drug, in patients with IBS. We evaluated the efficacy of long-acting mesalamine in patients with PI-IBS.

METHODS

Sixty-one patients who developed diarrhea-predominant IBS (IBS-D) after gastroenteritis were randomized to receive either 2.4 g of long-acting mesalamine or placebo daily for 8-weeks. The symptoms assessed were abdominal pain, bloating, stool frequency, stool consistency, severity of diarrhea and constipation, satisfaction with bowel habits, and IBS affecting or interfering with life. Quality-of-life (QOL) was assessed using the IBS-QOL questionnaire. The prespecified primary outcome variable was the overall bowel symptom score (BSS) after 8-weeks of treatment. Effect sizes were expressed as standardized mean differences (Cohen's d).

RESULTS

Fifty-four patients completed the 8-week treatment (n = 28 mesalamine, n = 26 placebo), 49 (91%) were male, and age range 23-71 years (mean ± SD 43 ± 13). Mesalamine demonstrated superior efficacy compared to placebo on the primary outcome variable, overall BSS (Cohen's d = 0.57, p = 0.042). Mesalamine was also superior for the secondary outcome of how much IBS affects your life in general (d = 0.72, p = 0.01). For the secondary outcomes of IBS symptoms, 7 of the 7 symptoms had trends of mesalamine superiority. For the secondary outcomes of IBS-QOL subscales, 8 of 9 had trends of mesalamine superiority.

CONCLUSION

In patients with PI-IBS, long-acting mesalamine demonstrated to be effective in reducing IBS symptoms and improving QOL.

Journal of Clinical Gastroenterology Lectureship Dubai 2022 : Management of Irritable Bowel Syndrome With Diarrhea

Irritable bowel syndrome (IBS) with diarrhea (IBS-D) affects ~1% of the general population and is characterized by abdominal pain associated with diarrhea. IBS-D symptoms significantly impact the quality of life of patients. Major uncertainties remain regarding the optimal management of these patients. Several therapies have been investigated over the years for the treatment of IBS-D. In the initial management, commonly prescribed approaches with an effect on global IBS symptoms include a low Fermentable Oligo-, Di-, Mono-Saccharides and Polyols diet and probiotics, while antispasmodics are used for targeting abdominal pain and loperamide for diarrhea only. Additional therapeutic options for the relief of global IBS symptoms include rifaximin, 5-HT 3 antagonists, gut-directed psychological therapies, and eluxadoline, while tricyclic antidepressants can target abdominal pain and bile acid sequestrants diarrhea. Promising evidence exists for the use of mesalazine and fecal microbiota transplantation in IBS-D, although further evidence is needed for definitive conclusions regarding their efficacy.

Systematic Review and Meta-analysis: Efficacy of Mesalamine in Irritable Bowel Syndrome

BACKGROUND & AIMS

Some patients with irritable bowel syndrome (IBS) demonstrate low-grade inflammation in the intestine. Mesalamine, which has anti-inflammatory effects, may be an efficacious treatment for IBS, but studies are conflicting. We conducted a systematic review and meta-analysis to assess efficacy and safety of mesalamine in IBS.

METHODS

We searched the medical literature up to September 14, 2022, to identify randomized controlled trials (RCTs) of mesalamine in IBS. We judged efficacy and safety using dichotomous assessments of effect on global IBS symptoms, abdominal pain, bowel habit or stool frequency, and occurrence of any adverse event. We pooled data using a random effects model, with efficacy and safety reported as pooled relative risks (RRs) with 95% confidence intervals (CIs).

RESULTS

We identified 8 eligible RCTs (820 patients). Mesalamine was more efficacious than placebo for global IBS symptoms (RR of global symptoms not improving, 0.86; 95% CI, 0.79-0.95; number needed to treat = 10; 95% CI, 6-27), but not for abdominal pain or bowel habit or stool frequency. Subgroup analyses demonstrated efficacy of mesalamine in IBS with diarrhea for global IBS symptoms (RR, 0.88; 95% CI, 0.79-0.99), but not patients with other predominant bowel habits or those with post-infection IBS. Adverse event rates were no higher with mesalamine (RR, 1.20; 95% CI, 0.89-1.63) but were reported in only 5 trials.

CONCLUSIONS

Mesalamine may be modestly efficacious for global symptoms in IBS, particularly IBS with diarrhea, but quality of evidence was low. Adequately powered high quality RCTs of mesalamine in IBS are needed.

Mast Cell Disorders of the Gastrointestinal Tract: Clarity out of Chaos

Pathologists are increasingly asked to evaluate mast cell infiltrates in the gastrointestinal tract when there is clinical concern for systemic mastocytosis or a variety of functional disorders, including irritable bowel syndrome and mast cell activation syndrome. Neoplastic mast cells have established quantitative, morphologic, and immunohistochemical features that facilitate their identification in gastrointestinal mucosal biopsies. Specific qualitative and quantitative findings are lacking for inflammatory mast cell-mediated disorders. This review covers histopathologic features of mast cell disorders that affect the gastrointestinal tract and offers practical guidance for their assessment in mucosal biopsies.

Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) are an extremely common set of more than 50 disorders characterized by persistent and recurring gastrointestinal symptoms. Most of these patients can be diagnosed and managed by primary care physicians. Treatment includes patient education and reassurance, eliminating triggers, dietary modification, and pharmacologic management. Primary care physicians should consider referral to gastroenterologists when patients exhibit red flag symptoms such as blood in stool, abnormal laboratory findings, involuntary weight loss, age of presentation greater than 50 years, or certain concerning family history.

Understanding neuroimmune interactions in disorders of gut-brain interaction: from functional to immune-mediated disorders

Functional gastrointestinal disorders-recently renamed into disorders of gut-brain interaction-such as irritable bowel syndrome and functional dyspepsia are highly prevalent conditions with bothersome abdominal symptoms in the absence of structural abnormalities. While traditionally considered as motility disorders or even psychosomatic conditions, our understanding of the pathophysiology has evolved significantly over the last two decades. Initial observations of subtle mucosal infiltration with immune cells, especially mast cells and eosinophils, are since recently being backed up by mechanistic evidence demonstrating increased release of nociceptive mediators by immune cells and the intestinal epithelium. These mediators can activate sensitised neurons leading to visceral hypersensitivity with bothersome symptoms. The interaction between immune activation and an impaired barrier function of the gut is most likely a bidirectional one with alterations in the microbiota, psychological stress and food components as upstream players in the pathophysiology. Only few immune-targeting treatments are currently available, but an improved understanding through a multidisciplinary scientific approach will hopefully identify novel, more precise treatment targets with ultimately better outcomes.

Insights into Mesalazine Use in Clinical Practice of Young Gastroenterologists

BACKGROUND

Mesalazine is among the medications most prescribed by gastroenterologists, with variable and controversial use in different settings. We aimed to explore the use of mesalazine in the clinical practice of young gastroenterologists.

METHODS

A web-based electronic survey was distributed to all participants of the National Meeting of the Italian Young Gastroenterologist and Endoscopist Association.

RESULTS

A total of 101 participants took part in the survey, with a majority (54.4%) being aged >30 years, 63.4% of whom were trainees in academic hospitals, and 69.3% of whom were involved in the clinical management of inflammatory bowel disease (IBD). While both non-dedicated and IBD physicians generally agreed on the appropriate dose of mesalazine for mild ulcerative colitis (UC), significant differences were observed between the two groups for moderate-severe ulcerative colitis (UC). Additionally, in IBD patients who were starting immuno-modulators and/or biologics, 80% of IBD-dedicated physicians continued to prescribe mesalazine, compared to 45.2% of non-dedicated physicians (p = 0.002). Indeed, 48.4% of non-dedicated IBD physicians did not acknowledge mesalazine for colorectal cancer chemoprevention. With regards to Crohn's disease, it is mainly used by 30.1% of IBD physicians for preventing postoperative recurrence of Crohn's disease. Finally, 57.4% used mesalazine for symptomatic uncomplicated diverticular disease, and 84.2% did not recommend its use for irritable bowel syndrome.

CONCLUSIONS

This survey showed heterogeneous behaviors in the daily use of mesalazine, mainly in the management of IBD. Educational programs and novel studies are needed to clarify its use.

Irritable bowel syndrome: treatment based on pathophysiology and biomarkers

OBJECTIVE

To appraise the evidence that pathophysiological mechanisms and individualised treatment directed at those mechanisms provide an alternative approach to the treatment of patients with irritable bowel syndrome (IBS).

DESIGN

A PubMED-based literature review of mechanisms and treatment of IBS was conducted independently by the two authors, and any differences of perspective or interpretation of the literature were resolved following discussion.

RESULTS

The availability of several noninvasive clinical tests can appraise the mechanisms responsible for symptom generation in IBS, including rectal evacuation disorders, abnormal transit, visceral hypersensitivity or hypervigilance, bile acid diarrhoea, sugar intolerances, barrier dysfunction, the microbiome, immune activation and chemicals released by the latter mechanism. The basic molecular mechanisms contributing to these pathophysiologies are increasingly recognised, offering opportunities to intervene with medications directed specifically to food components, receptors and potentially the microbiome. Although the evidence supporting interventions for each mechanism is not at the same level of proof, the current state-of-the-art provides the opportunity to advance the practice from treatment based on symptoms to individualisation of treatment guided by pathophysiology and clinically identified biomarkers.

CONCLUSION

These advances augur well for the implementation of evidence-based individualised treatment for patients with IBS based on actionable biomarkers or psychological disturbances.

Role of inflammation in pediatric irritable bowel syndrome

BACKGROUND

IBS affects a large number of children throughout the world and is thought to be the result of disturbed neuroimmune function along with the brain-gut axis. Although the underlying pathophysiologic mechanisms are not clear, the role of low-grade inflammation and mucosal immune activation in IBS symptom generation has become evident also in subsets of pediatric patients. Animal models provided meaningful insight in the causal relationship between abnormal mucosal immune activation and changes in gastrointestinal (GI) sensory-motor function. Likewise, the development of long-standing GI symptoms fulfilling the current criteria for functional GI disorders after infection gastroenteritis and in patients with IBD or celiac disease in remission further supports this hypothesis. Immune activation, its impact on gut sensory-motor function, and potential implications for symptom generation emerged in both children and adults with IBS.

PURPOSE

The aim of this review is to summarize the main evidence on the presence of low-grade inflammation and immune activation in children with IBS, its possible role in symptom generation, and its potential implication for new therapeutic strategies.

What Is the Value of Counting Mast Cells in Gastrointestinal Mucosal Biopsies?

Neoplastic and nonneoplastic mast cell disorders can cause diarrhea, nausea, and abdominal pain that result from heightened release of mast cell mediators. Systemic mastocytosis is characterized by neoplastic mast cell aggregates in the bone marrow and other sites, particularly the skin and gastrointestinal tract. In this situation, extramedullary mast cell aggregates display atypical morphology, with aberrant immunostaining for CD25 in addition to staining for other mast cell markers, such as mast cell tryptase and CD117. Morphologically normal mast cells have also been implicated in nonneoplastic conditions. For example, increased mast cell numbers have been reported in the mucosal biopsy samples from patients with irritable bowel syndrome and hereditary alpha-tryptasemia. Patients with mast cell activation syndrome presumably experience symptoms related to the aberrant elaboration of histamine and other mediators from normal-appearing mast cells present in normal numbers. Unfortunately, similarities in terminology among these biologically distinct clinical conditions have caused considerable diagnostic confusion among clinical colleagues, resulting in frequent requests for pathologists to quantify and characterize mast cells in normal gastrointestinal biopsy samples from patients with diarrheal symptoms. The purpose of this review is to summarize the available data related to mast cell assessment in the gastrointestinal tract and provide pathologists with practical information so that they can help their clinical colleagues manage patients with presumed mast cell disorders.

MicroRNA-155-5p inhibition alleviates irritable bowel syndrome by increasing claudin-1 and ZO-1 expression

Background

Irritable bowel syndrome (IBS) is a common gastrointestinal disease. Emerging studies have demonstrated that microRNAs (miRNAs) are commonly dysregulated in patients with IBS, and aberrant miRNAs are implicated in IBS occurrence. Although miR-155-5p participates in inflammatory bowel disease (IBD) and intestinal barrier dysfunction, the role of miR-155-5p in IBS is unclear.

Methods

In the present study, colon samples were obtained from IBS patients and IBS mice induced by trinitrobenzenesulfonic acid (TNBS), and the levels of miR-155-5p, claudin-1 (CLDN1), and zonula occludens-1 (ZO-1) were assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemical analysis. The regulatory role of miR-155-5p in CLDN1 and ZO-1 expression was validated using dual luciferase reporter assay.

Results

We found that miR-155-5p levels were upregulated in colon samples of IBS patients and mice compared with healthy subjects and normal mice, respectively. Meanwhile, the levels of CLDN1 and ZO-1 were decreased in colon samples of IBS patients and mice. Importantly, forced expression of miR-155-5p inhibited CLDN1 and ZO-1 expression. In IBS mice, intraperitoneal injection with miR-155-5p inhibitor increased CLDN1 and ZO-1 expression in intestinal mucosal epithelium, enhanced visceral response thresholds, and decreased myeloperoxidase (MPO) activity.

Conclusions

In summary, these results suggested that miR-155-5p participated in the pathogenesis of IBS, at least in part by inhibiting CLDN1 and ZO-1 expression, indicating that miR-155-5p may be a potential therapeutic target for IBS.

Randomised clinical trial and meta-analysis: mesalazine treatment in irritable bowel syndrome-effects on gastrointestinal symptoms and rectal biomarkers of immune activity

BACKGROUND

Low-grade immune activation in the gut is a potential treatment target in irritable bowel syndrome (IBS).

AIMS

To determine improvement in IBS symptoms after mesalazine treatment, and the utility of measures of immune activity in the rectal mucosa METHODS: This was a randomised, double-blind, placebo-controlled, parallel-arm, multicentre trial in subjects with IBS (Rome III criteria), with an eight-week treatment period of mesalazine 2400 mg or plcebo once-daily. The primary endpoint was the global assessment of satisfactory relief of IBS symptoms in ≥50% of weeks during intervention. IBS symptoms were also measured with the IBS severity scoring system; immune activity was measured by mucosal patch technology. A post hoc meta-analysis of randomised placebo-controlled trials of mesalazine in IBS was added.

RESULTS

Of 181 included patients, 91 received mesalazine and 90 received placebo. The primary endpoint was met by 32 (36%) patients after mesalazine and 27 (30%) after placebo (p = 0.40). There were no differences in response rates related to IBS subtype or post-infection symptom onset. More reduction of abdominal bloating was noted in the mesalazine group (p = 0.02). The meta-analysis showed no effect of mesalazine on IBS symptoms. No mucosal patch technology measure could predict response to mesalazine, and found no differences in the effects of intervention on levels of immune markers.

CONCLUSIONS

Mesalazine is ineffective in reducing IBS symptoms. Rectal measures of immune activity by the mucosal patch technology cannot predict a higher chance of response to mesalazine.

Mast cell mediation of visceral sensation and permeability in irritable bowel syndrome

Abnormalities of mast cell structure or function may play prominent roles in irritable bowel syndrome (IBS) symptom genesis. Mast cells show close apposition to sensory nerves and release bioactive substances in response to varied stimuli including infection, stress, and other neuroendocrine factors. Most studies focus on patients who develop IBS after enteric infection or who report diarrhea-predominant symptoms. Three topics underlying IBS pathogenesis have been emphasized in recent investigations. Visceral hypersensitivity to luminal stimulation is found in most IBS patients and may contribute to abdominal pain. Mast cell dysfunction also may disrupt epithelial barrier function which alters mucosal permeability potentially leading to altered bowel function and pain. Mast cell products including histamine, proteases, prostaglandins, and cytokines may participate in hypersensitivity and permeability defects, especially with diarrhea-predominant IBS. Recent experimental evidence indicates that the pronociceptive effects of histamine and proteases are mediated by the generation of prostaglandins in the mast cell. Enteric microbiome interactions including increased mucosal bacterial translocation may activate mast cells to elicit inflammatory responses underlying some of these pathogenic effects. Therapies to alter mast cell activity (mast cell stabilizers) or function (histamine antagonists) have shown modest benefits in IBS. Future investigations will seek to define patient subsets with greater potential to respond to therapies that address visceral hypersensitivity, epithelial permeability defects, and microbiome alterations secondary to mast cell dysfunction in IBS.

A Nonviable Probiotic in Irritable Bowel Syndrome: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Study

BACKGROUND & AIMS

The aim of this study was to investigate the effectiveness of oral treatment with a nonviable probiotic lysate (BL) of Escherichia coli (DSM 17252) and Enterococcus faecalis (DSM 16440) in patients with irritable bowel syndrome (IBS).

METHODS

A phase IV, randomized, double-blind, placebo-controlled, multicenter (30 study sites), parallel group study was conducted in 389 patients of both sexes with IBS according to Rome III criteria. The treatment period was 26 weeks. The participants were allocated to either placebo or BL after a 2-week baseline period. The primary outcome was based on the European Medicines Agency IBS guideline: improvement in global assessment (GAI) and improvement in abdominal pain.

RESULTS

Patients (BL, n = 191; placebo, n = 198) had similar baseline values and dropout rates. Overall, the response was similar between BL and placebo for IBS-GAI (17.4% and 14.4%, respectively; P = ·4787) and abdominal pain (42.0% and 35.4%, respectively; P = ·1419). Some secondary outcome measures and sensitivity analyses pointed toward potentially higher sensitivity of the abdominal pain measures in diarrhea-predominant IBS (IBS-D) but not the other subtypes. For the GAI, no subgroup differences were detected. For IBS-D, post hoc analyses for abdominal pain response over time and stool consistency showed potentially promising effects of BL. Finally, the treatment with BL was well-tolerated.

CONCLUSIONS

BL is not effective across all IBS subtypes. However, BL may offer a treatment option for IBS-D that needs verification by an adequately powered drug trial; EudraCT-No.: 2012-002741-38.

Placebo Response Rates in Trials of Licensed Drugs for Irritable Bowel Syndrome With Constipation or Diarrhea: Meta-analysis

BACKGROUND & AIMS

There are several licensed drugs for irritable bowel syndrome (IBS) that have proven efficacy in randomized controlled trials (RCTs), but placebo response rates are high. We conducted a systematic review and meta-analysis of licensed drugs to estimate magnitude of placebo response rate according to Food and Drug Administration (FDA)-recommended endpoints and to assess how this varies with stringency of the endpoint used to define response.

METHODS

We searched MEDLINE, EMBASE CLASSIC and EMBASE, and the Cochrane central register of controlled trials (through January 2021) to identify RCTs comparing licensed drugs with placebo in adult IBS patients. Studies assessed efficacy according to at least one of composite response, abdominal pain response, or stool response. Data were extracted as intention-to-treat analyses, with dropouts assumed to be treatment failures and pooled using a random-effects model.

RESULTS

There were 17 RCTs of licensed drugs versus placebo in IBS with constipation (4603 patients placebo) and 17 trials in IBS with diarrhea (3908 patients placebo). In IBS with constipation, according to FDA criteria, pooled composite, abdominal pain, and stool response rates with placebo over ≥6 of 12 weeks were 18.9%, 34.6%, and 30.1%, respectively. Evaluating response rates over ≥9 of 12 weeks led to placebo response rates of 4.3% for the composite endpoint, 24.5% for abdominal pain, and 7.7% for stool. In IBS with diarrhea, pooled placebo response rates according to FDA criteria were 16.2% for the composite endpoint, 40.2% for abdominal pain, and 16.2% for stool. Increasing the threshold used to define abdominal pain response from ≥30% improvement to ≥40% or ≥50% led to lower placebo response rates of 34.5% and 23.4%.

CONCLUSIONS

Future RCTs should adhere to current FDA-recommended endpoints for IBS because these lead to lower placebo response rates. However, consideration should be given to further refining some of these to better differentiate between active drug and placebo.

Immune activation in irritable bowel syndrome: what is the evidence?

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder that is characterized by abdominal pain and an altered defecation pattern. It affects between 5 and 20% of the general population and can seriously impact quality of life. The pathophysiology of IBS is rather complex and multifactorial including, for example, altered signalling by the gut-brain axis, dysbiosis, abnormal visceral pain signalling and intestinal immune activation. The latter has gained particular interest in recent years, with growing insight into the bidirectional communication between the nervous system and the immune system. In this Review, we detail the current evidence suggesting that immune activation contributes to the pathology seen in patients with IBS and discuss the potential mechanisms involved. Moreover, we describe how immune mediators, particularly those released by mast cells, can directly activate or sensitize pain-transmitting nerves, leading to increased pain signalling and abdominal pain. Finally, we discuss the potential of interventions targeting immune activation as a new therapeutic strategy for patients suffering from IBS.

Current Treatment Options and Therapeutic Insights for Gastrointestinal Dysmotility and Functional Gastrointestinal Disorders

Functional gastrointestinal disorders (FGIDs) have been re-named as disorders of gut-brain interactions. These conditions are not only common in clinical practice, but also in the community. In reference to the Rome IV criteria, the most common FGIDs, include functional dyspepsia (FD) and irritable bowel syndrome (IBS). Additionally, there is substantial overlap of these disorders and other specific gastrointestinal motility disorders, such as gastroparesis. These disorders are heterogeneous and are intertwined with several proposed pathophysiological mechanisms, such as altered gut motility, intestinal barrier dysfunction, gut immune dysfunction, visceral hypersensitivity, altered GI secretion, presence and degree of bile acid malabsorption, microbial dysbiosis, and alterations to the gut-brain axis. The treatment options currently available include lifestyle modifications, dietary and gut microbiota manipulation interventions including fecal microbiota transplantation, prokinetics, antispasmodics, laxatives, and centrally and peripherally acting neuromodulators. However, treatment that targets the pathophysiological mechanisms underlying the symptoms are scanty. Pharmacological agents that are developed based on the cellular and molecular mechanisms underlying pathologies of these disorders might provide the best avenue for future pharmaceutical development. The currently available therapies lack long-term effectiveness and safety for their use to treat motility disorders and FGIDs. Furthermore, the fundamental challenges in treating these disorders should be defined; for instance, 1. Cause and effect cannot be disentangled between symptoms and pathophysiological mechanisms due to current therapies that entail the off-label use of medications to treat symptoms. 2. Despite the knowledge that the microbiota in our gut plays an essential part in maintaining gut health, their exact functions in gut homeostasis are still unclear. What constitutes a healthy microbiome and further, the precise definition of gut microbial dysbiosis is lacking. More comprehensive, large-scale, and longitudinal studies utilizing multi-omics data are needed to dissect the exact contribution of gut microbial alterations in disease pathogenesis. Accordingly, we review the current treatment options, clinical insight on pathophysiology, therapeutic modalities, current challenges, and therapeutic clues for the clinical care and management of functional dyspepsia, gastroparesis, irritable bowel syndrome, functional constipation, and functional diarrhea.

Evaluation of bowel habits in patients with acne vulgaris

PURPOSE

To evaluate the bowel habits of patients with acne vulgaris.

METHOD

In this case-control study, socio-demographical characteristics of the participants (age, gender, marital status, educational status, profession, economic status, smoking-alcohol habits, chronic diseases, previous operations, people they live with and diet) were questioned and the global acne grading scores of the patients were calculated. Bristol Stool Scale, Rome III IBS Criteria, International Physical Activity Questionnaire-Short Form, Hospital Anxiety Depression and KADF (dietary fibre information) scales were completed.

RESULTS

The patient group consisted of 102 participants and the control group consisted of 104 participants. The mean age was 20.9 ± 3.9 years old in the case group and 21.8 ± 5.0 years old in the control group. Patient and control groups were similar in terms of age and gender. Smoking rates were significantly higher in the patient group (P = .035). The amount of coffee consumed/day was significantly higher in the patient group (P = .040). According to the global acne grading scores, 55.9% (n = 57) had medium, 39.2% (n = 40) had mild, 3.9% (n = 4) had severe and 1% (n = 1) had very severe acne. Anxiety scores were found to be significantly higher in the patient group (P = .005). When the case and control groups were compared for IBS presence, no significant difference was found (P = .317). Also, IBS was not related to acne severity (P = .162).

CONCLUSION

Further large sample sized studies are needed on this subject, as there is strong evidence about brain-gut-skin axis existence.

The placebo response rate in pharmacological trials in patients with irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Clinical trials in irritable bowel syndrome are associated with high placebo response rates. We aimed to identify the magnitude of the placebo response and the contributing factors to this occurrence.

METHODS

We did a systematic review and meta-analysis with a search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials between April 1, 1959, and April 30, 2020. We included all randomised controlled trials that compared an active pharmacotherapeutic agent with placebo and had a dichotomous outcome of response to therapy (in terms of global improvement or improvement in abdominal pain) in adults (aged ≥18 years) with irritable bowel syndrome. Exclusion criteria were trials reporting on treatment satisfaction as a dichotomous outcome of response to therapy or clinician-reported outcomes and a treatment duration of less than 4 weeks. Our main outcome was identification of the magnitude of the pooled placebo response rate for the following endpoints: global improvement, abdominal pain, and US Food and Drug Administration (FDA) endpoints. We extracted information from published reports and pooled proportions through meta-analysis with random effects. The study was registered with PROSPERO, CRD42020170908.

FINDINGS

Of the 6863 publications identified, 70 articles describing 73 randomised controlled trials were included in our analysis. The pooled placebo response rate was 27·3% (95% CI 24·3-30·9) using the global improvement endpoint, 34·4% (31·2-37·8) using the abdominal pain endpoint, and 17·9% (15·2-21·0) using the composite FDA endpoint responder definition, all with substantial heterogeneity between the trials. Studies published before 2006, and those done in Europe, with a parallel design, a run-in period of 2 weeks or less, a dose schedule of three times a day or more, or a smaller sample size of the control group were significantly associated with an increased pooled placebo response rate.

INTERPRETATION

More than a quarter of patients with irritable bowel syndrome had a placebo response in terms of global improvement, with multiple associated moderators. We recommend future trials apply a run-in period of at least 2 weeks and dose once or twice a day to minimise the placebo response rate.

FUNDING

None.

Colonic Gene Expression and Fecal Microbiota in Diarrhea-predominant Irritable Bowel Syndrome: Increased Toll-like Receptor 4 but Minimal Inflammation and no Response to Mesalazine

Background/Aims

Diarrhea-predominant irritable bowel syndrome (IBS-D) has been previously associated with evidence of immune activation and altered microbiota. Our aim is to assess the effect of the anti-inflammatory agent, mesalazine, on inflammatory gene expression and microbiota composition in IBS-D.

Methods

We studied a subset of patients (n = 43) from a previously published 12-week radomized placebo-controlled trial of mesalazine. Mucosal biopsies were assessed by immunohistochemistry and reverse transcription-polymerase chain reaction for a range of markers of inflammation, altered permeability, and sensory receptors including Toll-like receptors (TLRs) at randomization after treatment. All biopsy data were compared to 21 healthy controls. Patient’s stool microbiota composition was analysed through 16S ribosomal RNA sequencing.

Results

We found no evidence of increased immune activation compared to healthy controls. However, we did find increased expression of receptors in both sensory pathways and innate immune response including TLR4. Higher TLR4 expression was associated with greater urgency. TLR4 expression correlated strongly with the expression of the receptors bradykinin receptor B2, chemerin chemokine-like receptor 1, and transient receptor potential cation channel, subfamily A, member 1 as well as TLR4’s downstream adaptor myeloid differentiation factor 88. Mesalazine had minimal effect on either gene expression or microbiota composition.

Conclusions

Biopsies from a well-characterized IBS-D cohort showed no substantial inflammation. Mesalazine has little effect on gene expression and its previous reported effect on fecal microbiota associated with much greater inflammation found in inflammatory bowel diseases is likely secondary to reduced inflammation. Increased expression of TLR4 and correlated receptors in IBS may mediate a general increase in sensitivity to external stimuli, particularly those that signal via the TLR system.

Inflammation and Overlap of Irritable Bowel Syndrome and Functional Dyspepsia

Irritable bowel syndrome (IBS) and functional dyspepsia (FD) are common functional gastrointestinal disorders (FGIDs) and account for a large proportion of consulting patients. These 2 disorders overlap with each other frequently. The pathogenesis of IBS or FD is complicated and multi-factors related, in which infectious or non-infectious inflammation and local or systemic immune response play significant roles. There are few studies focusing on the mechanism of inflammation in patients with overlap syndrome of irritable bowel syndrome and functional dyspepsia (IBS-FD). This review focuses on current advances about the role of inflammation in the pathogenesis of IBS and FD and the possible mechanism of inflammation in IBS-FD.

The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions

Functional gastrointestinal disorders (FGIDs), characterized by chronic abdominal complaints without a structural or biochemical cause, are common diseases that are frequently encountered by specialists in internal medicine. Collectively, irritable bowel syndrome (IBS) and functional dyspepsia are estimated to affect up to 22% of the population, and are often associated with additional somatic and pain complaints, all without an obvious structural source [1,2]. An appreciation of the current understanding of the mechanistic basis for these disorders is key to developing treatment goals and optimization of patient management strategies. In recent years, the brain-gut axis increasingly has been recognized as a central factor in the experience of functional abdominal pain disorders, including the most recent Rome IV guidelines which identify FGIDs as disorders of gut-brain interaction [3]. The brain-gut axis (BGA), simply defined, is a complex network of bidirectional communication between the central and enteric nervous systems. This axis broadly includes all the systems involved with communication between the GI tract and central nervous system (CNS), with principle inputs into this network occurring between the CNS, enteric nervous system (ENS), and autonomic nervous systems (ANS), but also includes interfaces with numerous other factors, including endocrine hormones and immune effector cells as well as interactions with the gut microbiota. Perturbances to this system have been found to play a critical role in the development of visceral hypersensitivity, bowel dysregulation, and mood. This review will summarize the principle processes involved in the neurologic and biologic function of the brain-gut axis, our current understanding of its role in functional GI disorders, and potential targets for therapeutic intervention.

Therapeutic, Prophylactic, and Functional Use of Probiotics: A Current Perspective

Probiotics are considered as the twenty-first century panpharmacon due to their competent remedial power to cure from gastrointestinal dysbiosis, systematic metabolic diseases, and genetic impairments up to complicated neurodegenerative disorders. They paved the way for an innovative managing of various severe diseases through palatable food products. The probiotics' role as a "bio-therapy" increased their significance in food and medicine due to many competitive advantages over traditional treatment therapies. Their prophylactic and therapeutic potential has been assessed through hundreds of preclinical and clinical studies. In addition, the food industry employs probiotics as functional and nutraceutical ingredients to enhance the added value of food product in terms of increased health benefits. However, regardless of promising health-boosting effects, the probiotics' efficacy still needs an in-depth understanding of systematic mechanisms and factors supporting the healthy actions.

The anti-inflammatory and immune-modulatory effects of OEA limit DSS-induced colitis in mice

Fatty acid ethanolamides acting on proliferator-activated receptor (PPAR)-α are among the endogenous lipid molecules that attenuate inflammatory processes and pain sensitivity. Whereas these properties are well-known for palmitoylethanolamide (PEA), the efficacy of oleoylethanolamide (OEA, first described as a satiety hormone synthesized in the jejunum) has been overlooked. In this study, we aimed to evaluate the effect of OEA administration in a mouse model of colitis. C57BL/6J mice were exposed to 2.5% dextran sodium sulphate (DSS) in drinking water for 5 days. Daily i.p. administration of 10 mg/kg OEA started 3 days before DSS and lasted for 12 days. The DSS-untreated control group received only ultrapure water. DSS mice treated with OEA had a significant improvement of disease score. OEA restored mRNA transcription of PPAR-α, of tight junctions and protective factors of colon integrity disrupted by DSS. The improvement correlated with significant decrease of colonic and systemic levels of pro-inflammatory cytokines compared to the DSS group. OEA antiinflammatory effects were mediated by the selective targeting of the TLR4 axis causing a downstream inhibition of nuclear factor kappa B (NF-κB)- MyD88-dependent and NLRP3 inflammation pathways. OEA treatment also inhibited DSS-induced increase of inflammatory cytokines levels in the mesenteric lymph nodes. CONCLUSIONS AND IMPLICATIONS: These results underscore the validity of OEA as a potent protective and anti-inflammatory agent in ulcerative colitis that may be exploited to broaden the pharmacological strategies against inflammatory bowel disease.

The relationship between acne vulgaris and irritable bowel syndrome: A preliminary study

BACKGROUND

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease characterized by chronic abdominal pain and changes in bowel movements without underlying organic pathology. Many skin diseases have been reported to be more common in individuals with functional bowel diseases.

AIMS

In this study, we aimed to investigate a possible relationship between acne vulgaris (AV) and IBS.

PATIENTS/METHODS

This prospective controlled study included patients with AV and healthy volunteers. All the subjects were evaluated in terms of the presence of IBS. The diagnosis of IBS was made based on the ROME IV diagnostic criteria. The clinical severity of AV was calculated using the global acne grading system (GAGS).

RESULTS

A total of 300 patients with acne vulgaris and 300 age and gender-matched healthy controls were included in the study. The majority of the patients were female (n = 175, 58.3%). The mean ages of the patients and controls were 20.22 ± 5.24 years and 20.49 ± 5.36 years, respectively. A total of 183 patients (61.0%) and 84 (28.0%) controls were diagnosed with IBS based on the Rome IV diagnostic criteria. The frequency of IBS was statistically significantly higher in the patient group than in the control group. (P = .001). There was also statistically significant relationship between the GAGS scores and IBS diagnosis (P = .001), abnormal stool form (P = .001), abdominal distention (P = .001), and feeling of incomplete evacuation (P = .001).

CONCLUSION

Our study showed that IBS is significantly more common in patients with AV than in healthy controls. Additionally, GAGS scores were higher in patients diagnosed with IBS. To the best of our knowledge, this is the first study focusing on the subject.

Confocal laser endomicroscopy detects colonic inflammation in patients with irritable bowel syndrome: a prospective study

Background and aims  Irritable bowel syndrome (IBS) is considered to be a functional disease, but recent data indicate measurable organic alterations. We aimed to determine the presence of colorectal mucosa microinflammation in vivo via probe-confocal laser endomicroscopy (pCLE) and histological evaluation in IBS patients. Methods  This was a prospective, controlled, nonrandomized single-blind diagnostic trial performed in a tertiary institution. pCLE images and targeted biopsy of each colon segment obtained during colonoscopies of IBS patients and controls were analyzed for inflammatory changes. Biopsies were classified using the Geboes scale, and the odds ratio and overall diagnostic accuracy were calculated. Results  During the 15-month study period, 37 patients were allocated to each group. The mean age was 53.1 ± 14.3 years; 64.9 % were female. Signs of colonic mucosa inflammation were evident on 65.8 % of pCLE images from IBS patients compared to 23.4 % of images from controls (OR 6.28; 4.14-9.52; P  < 0.001). In total, 20/37 patients had microinflammation via pCLE in ≥ 3 colon segments in the IBS group, compared to 1/37 in the control group. A Geboes score > 0 was attributed to 60.8 % of biopsies from patients in the IBS group compared to 27.5 % of biopsies from the control group. The sensitivity, specificity, positive and negative predictive values, observed and interrater agreement of pCLE-detected inflammatory changes in IBS using histology as gold standard were 76 %, 91 %, 76 %, 91 %, 86.5 %, and 66.8 %, respectively. Conclusions  Patients with IBS have a six-fold higher prevalence of colorectal mucosa microinflammation than healthy controls. pCLE might be a reliable method to detect colorectal mucosa microinflammation in IBS patients.

New advances in the treatment of paediatric functional abdominal pain disorders

This Review summarises recent pharmacological and upcoming alternative interventions for children with functional abdominal pain disorders (FAPDs). Pharmacological targets include prokinetics and drugs affecting gastric accommodation to treat postprandial distress and nausea. Similarly, anti-inflammatory agents, junctional protein regulators, analgesics, secretagogues, and serotonin antagonists have a therapeutic role for irritable bowel syndrome. Non-pharmacological treatments include peripheral electrical nerve field stimulation to the external ear, gastric electrical stimulation, dietary interventions such as low fructose and fibre based diets, and nutraceuticals, which include probiotics, prebiotics, and synbiotics. Newer psychological advances such as exposure-based cognitive behavioural therapy, acceptance and commitment therapy, and mindfulness meditation are being investigated for paediatric functional pain. Lastly, alternative therapies such as acupuncture, moxibustion, yoga, and spinal manipulation are also gaining popularity in the treatment of FAPDs.

Inflammatory Bowel Diseases and Irritable Bowel Syndrome: Overlap of Two Nosological Forms or Two Variants of the Same Disease?

Aim. To review available literature data on the relationship between inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS).

Key findings. Current publications on IBD and IBS present different viewpoints on their relationship. Thus, researchers have noted a high incidence of IBD against the background of IBS, frequent persistence of IBS-like symptoms after achieving IBD remission, as well as the possibility of overlapping the diseases. According to literature data, IBD and IBS should be treated as different forms of the same disease. An opinion is expressed that IBS-like complaints in patients with IBD remission should be considered as a separate disease referred to as “irritated inflammatory intestinal syndrome”. Treatment of IBS-like symptoms in patients with IBD remission has thus far not been developed.

Conclusion. The problem of the relationship between IBD and IBS is currently controversial, thus requiring further clarification.

Gastrointestinal hypoalgesia in inflammatory bowel disease

Background:

Pain perception is critical for detection of noxious bodily insults. Gastrointestinal hypoalgesia in inflammatory bowel disease (IBD) is a poorly understood phenomenon previously linked to poor patient outcomes. We aimed to evaluate the risk factors associated with this condition and to discern characteristics that might differentiate these patients from pain-free quiescent counterparts.

Methods:

We performed a retrospective analysis using an IBD natural history registry based in a single tertiary care referral center. We compared demographic and clinical features in 3 patient cohorts defined using data from simultaneous pain surveys and ileocolonoscopy: a) active IBD without pain (hypoalgesic IBD); b) active IBD with pain; and c) inactive IBD without pain.

Results:

One hundred fifty-three IBD patients had active disease and 43 (28.1%) exhibited hypoalgesia. Hypoalgesic IBD patients were more likely to develop non-perianal fistulae (P=0.03). On logistic regression analysis, hypoalgesic IBD was independently associated with male sex, advancing age and mesalamine use, and inversely associated with anxious/depressed state and opiate use. Hypoalgesic IBD patients were demographically and clinically similar to the pain-free quiescent IBD cohort (n=59). Platelet count and C-reactive protein were more likely to be pathologically elevated in hypoalgesic IBD (P=0.03), though >25% did not exhibit elevated inflammatory markers.

Conclusions:

Hypoalgesia is common in IBD, particularly in male and older individuals, and is associated with an increased incidence of fistulae and corticosteroid use. Novel noninvasive diagnostic tools are needed to screen for this population, as inflammatory markers are not always elevated.

Atopic Dermatitis in Adults and Irritable Bowel Syndrome: A Cross-sectional Study

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder affecting a large number of people in the world. Atopic dermatitis (AD) is a common inflammatory skin condition characterized by relapsing eczematous lesions in a typical distribution. It was first described in 1933 but exists since antiquity.

AIM AND OBJECTIVES

To determine the relationship between AD and IBS.

MATERIALS AND METHODS

A total of 109 patients with AD and 100 healthy controls were included in the study. They were defined for diagnosis of IBS according to ROME-III diagnostic criteria. Supporting findings, Bristol stool scale, frequency of defecation and history of AD and IBS were also evaluated. AD severity was assessed using Severity Scoring of Atopic Dermatitis index.

RESULTS

A total of 62 patients (56.9%) in the AD group and 28 patients (28%) in the control group were diagnosed with IBS (P<0.001). Supportive findings excluding abnormal stool frequency and passage of mucus were more frequent in AD patients. There was no significant relationship between disease severity according to SCORAD index and variables in AD patients.

CONCLUSIONS

This is a rather uncultivated area in the field of AD. We observed that IBS was more common in AD group. Also, supporting findings like abnormal stool form, abdominal distension, feeling of incomplete evacuation, and straining were found more frequently in AD patients. These results may indicate the association between AD and IBS. In our opinion, patients with atopic dermatitis should be questioned in terms of IBS.

Utility of Diagnostic Tests in Children With Functional Abdominal Pain Disorders

Functional gastrointestinal disorders (FGIDs) and functional abdominal pain disorders (FAPDs) are common in pediatric patients. The prevalence of FGIDs using the Rome IV criteria ranges from 21.1% to 25.0% in children. The Rome IV criteria specify that the decision of testing is left to the clinician, giving him or her freedom to decide on the necessary workup. The clinician should consider all of the functional and organic diseases that manifest with chronic abdominal pain, as well as alarm features that should prompt testing. Societal guidelines and reports do not recommend routine evaluations for FAPDs, particularly in the absence of alarm features. Studies have reported variable results upon assessing the diagnostic yields of different tests. Furthermore, these evaluations considerably increase costs for the health care system. This article examines the current evidence on the utility of diagnostic testing in pediatric patients with FAPDs.

Twitter debate: controversies in functional gastrointestinal disorders

The new 'Controversies In…' series for the Frontline Gastroenterology Twitter debates addressed the difficult area of functional gastrointestinal disorders, facilitated by the former editor-in-chief Anton Emmanuel. Key topics discussed included distinguishing functional dyspepsia from genuine gastroparesis, when we should investigate for bile acid malabsorption, the current treatments for constipation-predominant irritable bowel syndrome and, importantly, how to manage consultations with complex patients presenting with functional bowel disease. The debate generated over a million impressions on twitter and this article aims to summarise the key educational points from the event.

Does Irritable Bowel Syndrome Exist? Identifiable and Treatable Causes of Associated Symptoms Suggest It May Not

Significant shortcomings in irritable bowel syndrome (IBS) diagnosis and treatment may arise from IBS being an “umbrella” diagnosis that clusters several underlying identifiable and treatable causes for the same symptom presentation into one classification. This view is compatible with the emerging understanding that the pathophysiology of IBS is heterogeneous with varied disease mechanisms responsible for the central pathological features. Collectively, these converging views of the pathophysiology, assessment and management of IBS render the traditional diagnosis and treatment of IBS less relevant; in fact, they suggest that IBS is not a disease entity per se and posit the question “does IBS exist?” The aim of this narrative review is to explore identifiable and treatable causes of digestive symptoms, including lifestyle, environmental and nutritional factors, as well as underlying functional imbalances, that may be misinterpreted as being IBS.

Effectiveness of mesalazine to treat irritable bowel syndrome: A meta-analysis

AIM

Accumulating evidence has explored the effect of mesalazine on irritable bowel syndrome (IBS). However, these studies remain inconsistent. Thus, a meta-analysis was conducted to estimate the role of mesalazine on IBS.

METHODS

PubMed, Medline, Embase, Web of Science, and the Cochrane Library Database were searched for all relevant randomized, controlled, blinded trials on mesalazine in patients with IBS between January 1980 and October 2018. All statistical analyses were performed using Revman 5.3 software. A fixed-effects model was adopted, 95% confidence intervals for SMD was calculated. Heterogeneity was evaluated by χ test and I statistic.

RESULTS

Five studies involving 387 participants were finally included in this meta-analysis. The results showed that the SMD for clinical efficacy on abdominal pain in IBS patients treated with mesalazine in comparison to placebo was 0.19 (95% CI = -0.01 to 0.39, P = .06), which was statistically non-significant but clinically important. For beneficial effect of abdominal bloating, the SMD was 0.05 (95% CI = -0.20 to 0.30, P = .70), which was statistically non-significant. In regard to clinical efficacy on defecation frequency per day, the results revealed that the SMD was 0.29 (95% CI = -0.14 to 0.73, P = .18), which was statistically non-significant but clinically important. As for beneficial effect of general well-being, we found that the SMD was 0.41 (95% CI = -0.75 to 1.58, P = .49), which was statistically non-significant. With respect to stool consistency, the SMD was 0.01 (95% CI = -0.31 to 0.33, P = .96), which was statistically non-significant. For the effect of defecation urgency severity in IBS patients treated with mesalazine in comparison to placebo, we detected a surprising result with an SMD of 0.54 (95% CI = 0.05-1.04, P = .03), which was statistically significant. There was no significant difference between mesalazine group and placebo group on total mucosal immune cell counts of the patients with IBS with an SMD of -1.64 (95% CI = -6.17 to 2.89, P = .48) and there was also no significant difference in adverse reactions between two groups with an SMD of 1.05 (95% CI = 0.76-1.46 P = .77).

CONCLUSION

Mesalazine is not superior to placebo in relieving clinical symptoms of abdominal pain, abdominal bloating, and general well-being of IBS and has no advantage of reducing defecation frequency per day and immune cell infiltration and improving stool consistency though without adverse reactions of mesalazine compared with placebo. For defecation urgency severity, placebo is even superior to mesalazine for IBS patients. Thus, mesalazine might be a cost burden to patients without providing good effectiveness. In view of the small sample size of the current study and the differences in every experimental designs, this study has high heterogeneity and requires subsequent verification.

Effects of Auricular Acupressure on Women With Irritable Bowel Syndrome

The purpose of this study was to examine the effect of auricular acupressure on bowel symptoms, stress, mental health, and heart rate variability in women with irritable bowel syndrome (IBS). A quasi-experimental study design with a nonequivalent control group assessed a total sample of 56 women diagnosed with IBS according to Rome III criteria. There were 29 women in the experimental group who received auricular acupressure; 27 women were in the control group. Semen sinapis albae seeds were used to administer acupressure to four auricular points: endocrine, large intestine, lung, and Shenmen for 5 days/week for 4 weeks; the control group received no treatment. Bowel symptoms, stress, mental health, and heart rate variability were measured twice, once before and once after the intervention. Chi-square tests, t tests, and paired t tests were used for analysis. The experimental group had decreased loose stools, abdominal pain, diarrhea, abdominal discomfort, stress, and heart rate variability compared with the control group (p < .05). Auricular acupressure was effective for symptom improvement in patients with IBS.

Expression of immune-related genes in rectum and colon descendens of Irritable Bowel Syndrome patients is unrelated to clinical symptoms

BACKGROUND

Mucosal immune activation has been postulated to play an important role in the pathogenesis of irritable bowel syndrome (IBS). However, data are conflicting and often based on small patient cohorts. Here, we aimed to evaluate the gene expression of a large set of immune-related genes in mucosal biopsies from IBS patients and healthy volunteers (HV).

METHODS

A total of 171 IBS patients and 127 HV were included in the study. Rectum biopsies were collected from a cohort of 70 HV and 77 IBS patients (Rome III) and colon descendens biopsies from another cohort of 57 HV and 94 IBS patients (Rome II). Gene expression was assessed using OpenArray technology, and validated questionnaires were used to evaluate clinical characteristics (GI symptoms, somatization, anxiety, and depression).

KEY RESULTS

A subset of IBS patients (33%) with increased immune activation in the colon descendens was identified using multivariate analysis and displayed increased gene expression of IL1B (3-fold change), prostaglandin synthase PTGS2 (2.1-fold change), and the G-protein-coupled receptor MRGPRX2 (10.7-fold change). Clinical characteristics in this subgroup were however similar to the rest of the patient cohort. Analysis of rectal biopsies failed to identify such subgroup of "immuno-active" IBS patients in the other patient cohort.

CONCLUSION

A subset of IBS patients reveals evidence of immune activation in the colon descendens, but not in the rectum; however, gene expression is unrelated to clinical symptoms. To what extent this subgroup might however respond to anti-inflammatory therapy remains to be investigated.

IBS clinical management in Italy: The AIGO survey

BACKGROUND

Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal disorder, both in primary and secondary care.

AIMS

(1) To describe diagnostic tools and treatments suggested to IBS patients by Italian gastroenterologists; (2) To evaluate patients' quality of life and psychological involvement and the relationship of these factors with symptom severity.

METHODS

Twenty-six gastroenterologists recorded the demographic and clinical data of 677 IBS patients. Diagnostic and treatment measures taken in the previous year and those suggested by gastroenterologists were analysed.

RESULTS

IBS with constipation was found in 43.4%, with diarrhoea in 21.6%, mixed-IBS in 35.0%. Routine blood tests, ultrasonography, colonoscopy, barium enema and CT were more frequently requested in the previous year than by the gastroenterologists (p < 0.001). Colonoscopy (11%), and ultrasonography (20.4%) were also suggested by the gastroenterologists in a non-negligible number of patients. Abdominal pain and distension, bowel dissatisfaction, anxiety and depression were more severe in females than in males. Quality of life decreased with increasing IBS-symptom severity.

CONCLUSIONS

IBS diagnosis is still largely based on exclusion criteria even if gastroenterologists try to improve diagnostic appropriateness. However, therapy remains symptom-based also in the gastroenterological setting even if gastroenterologists use a wide variety of approaches, including innovative therapies such as linaclotide and psychotherapy.

Activation of Peripheral Blood CD4+ T-Cells in IBS is not Associated with Gastrointestinal or Psychological Symptoms

Immune activation may underlie the pathogenesis of irritable bowel syndrome (IBS), but the evidence is conflicting. We examined whether peripheral CD4+ T-cells from IBS patients demonstrated immune activation and changes in cytokine production. To gain mechanistic insight, we examined whether immune activation correlated with psychological stress and changing symptoms over time. IBS patients (n = 29) and healthy volunteers (HV; n = 29) completed symptom and psychological questionnaires. IBS patients had a significant increase in CD4+ T-cells expressing the gut homing marker integrin β7 (p = 0.023) and lymphoid marker CD62L (p = 0.026) compared to HV. Furthermore, phytohaemagglutinin stimulated CD4+ T-cells from IBS-D patients demonstrated increased TNFα secretion when compared to HV (p = 0.044). Increased psychological scores in IBS did not correlate with TNFα production, while stress hormones inhibited cytokine secretion from CD4+ T-cells of HV in vitro. IBS symptoms, but not markers of immune activation, decreased over time. CD4+ T-cells from IBS-D patients exhibit immune activation, but this did not appear to correlate with psychological stress measurements or changing symptoms over time. This could suggest that immune activation is a surrogate of an initial trigger and/or ongoing parallel peripheral mechanisms.

Overlapping irritable bowel syndrome and inflammatory bowel disease

The pathogenesis of irritable bowel-type symptoms occurring in patients with inflammatory bowel disease who are in apparent remission continues to generate scientific controversy and the interpretation and management of these symptoms, so distressing to the sufferer, represent major challenges for the clinician. On the one hand, these symptoms often satisfy Rome IV criteria for IBS and their occurrence correlates highly with anxiety, a known trigger for IBS. On the other hand, recent studies have shown that many of these patients exhibit subtle inflammatory changes. These observations beg the question: are these symptoms "true" IBS superimposed on IBD, or an active but subclinical form of IBD? While it is certain that earlier studies failed to detect subclinical inflammation, it is also evident that even with the use of sensitive biomarkers for inflammation, such as calprotectin and lactoferrin backed up by pan-endoscopy and biopsy to exclude ongoing inflammatory activity in its most subtle form, the prevalence of IBS-type symptoms remains higher than expected in the IBD patient. Pending further definition of its etiology and pathology, we coined the term irritable inflammatory bowel syndrome (IIBS) to refer to this phenomenon. Here we explore the risk factors for this entity, sift through clues to its pathogenesis and attempt to provide, albeit bereft of a robust evidence base, an approach to its management.

Irritable bowel syndrome and colonic diverticular disease: overlapping symptoms and overlapping therapeutic approaches

PURPOSE OF REVIEW

Irritable bowel syndrome (IBS) is a common symptomatic disorder in the Western world and colonic diverticula are also prevalent; however, relationships between IBS-type symptoms and diverticula have been a source of much debate. Our goal was to reassess these relationships in the light of new data.

RECENT FINDINGS

On removing from consideration clinical scenarios which are directly related to diverticula (i.e., diverticulitis, diverticular hemorrhage, and complications of diverticulitis, such as stricture and fistula), relationships between IBS and diverticula can be seen to revolve around a number of questions. First, are IBS and symptomatic uncomplicated diverticular disease (SUDD) the same condition? Or, in other words is SUDD no more than IBS in an individual who just happens to have diverticula? Although coincident IBS and diverticula inevitably do occur there is some evidence to indicate that SUDD may be somewhat distinctive with SUDD being characterized by more frequent and severe pain. Second, and analogous to interactions between IBS and inflammatory bowel disease or celiac disease, can an episode of acute diverticulitis lead to the de novo development of IBS? There is now epidemiological and pathophysiological evidence to support this occurrence.

SUMMARY

Although relationships between uncomplicated diverticular disease and IBS have been reexamined their status remains unclear. As yet, however, none of the newer concepts related to this relationship have led to new therapeutic approaches in IBS or diverticular disease.

New treatments and therapeutic targets for IBS and other functional bowel disorders

Functional bowel disorders (FBDs) are a spectrum of disorders characterized by combinations of symptoms attributable to the lower gastrointestinal tract. Most current first-line therapies for IBS and other FBDs target the predominant symptom and mainly affect one symptom in the symptom complex. Additional broadly effective treatment alternatives targeting the entire symptom complex are needed. New drugs for FBDs (such as lubiprostone, linaclotide, plecanatide, prucalopride, eluxadoline and rifaximin) target key mechanisms in the pathophysiology of these disorders and improve both the abnormal bowel habit and other key symptoms, such as abdominal pain and bloating. The current development of new treatment alternatives is focusing on different aspects of the complex pathophysiology of IBS and other FBDs: gut microenvironment (via diet and modulation of gut microbiota), enterohepatic circulation of bile acids, gastrointestinal secretion, motility and sensation, gut-brain interactions, gut barrier function and the immune system within the gastrointestinal tract. Studies also suggest that personalized treatment of IBS and other FBDs is possible using various diagnostic markers.

Systemic cytokines are elevated in a subset of patients with irritable bowel syndrome but largely unrelated to symptom characteristics

BACKGROUND

Serum levels of pro-inflammatory cytokines tend to be increased in irritable bowel syndrome (IBS) patients, or subgroups thereof. Still, the link between cytokine levels and IBS symptoms is unclear. We aim to determine systemic cytokine levels in IBS patients and healthy subjects (HS), confirm the presence of a subset of patients with an increased immune activity and to establish if cytokines are linked to IBS symptoms and pathophysiological factors.

METHODS

Serum levels of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF), and IL-10 were measured. All subjects reported IBS symptoms using validated questionnaires and underwent colonic sensorimotor testing. Multivariate supervised orthogonal partial least squares-discriminant analysis (OPLS-DA) and unsupervised principal component analysis (PCA) and hierarchical cluster analysis (HCA) were implemented.

KEY RESULTS

Irritable bowel syndrome patients (n = 246) had higher serum levels of IL-1β, IL-6, IL-8, TNF, and IL-10 compared to HS (n = 21); however, serum cytokine profiles could not discriminate patients from HS. Moreover, cytokine levels were not correlated with symptoms among patients. Supervised OPLS-DA identified 104 patients (40% of patients) and unsupervised HCA analysis identified 49 patients (20%) with an increased immune activity indicated by elevated levels of serum cytokines compared to HS and the other patients. However, irrespective of how patients with increased immune activity were identified they were symptomatically similar to patients with no indication of increased immune activity.

CONCLUSIONS & INFERENCES

Serum cytokines are elevated in IBS patients compared to HS. Immune activation characterizes a subset of patients, but modest associations between cytokine profile and symptoms suggest immune activity does not directly influence symptoms in IBS.

Guidelines on the management of irritable bowel syndrome: In memory of Professor Witold Bartnik

These guidelines constitute an update of the previous "Recommendations on the management of irritable bowel syndrome" issued in 2008. They have been developed by a Task Force organized by the Governing Board of the Polish Society of Gastroenterology. They discuss, with particular emphasis on new scientific data covering papers published since 2008, the aetiology, epidemiology, clinical presentation, diagnostic principles and criteria for the diagnosis, and recommendations for the treatment of irritable bowel syndrome (IBS). The English-language acronym for the syndrome (IBS) has become popular in medical and popular scientific language. It is also widely recognized by patients who identify with this diagnosis. Therefore, in the discussed guidelines, this is what we will use.

Cytokine Profile and Immunoglobulin E-mediated Serological Food Hypersensitivity in Patients With Irritable Bowel Syndrome With Diarrhea

Background/Aims

Food interaction, including food hypersensitivity, plays a key role in the pathogenesis of irritable bowel syndrome with diarrhea (IBS-D). Since only a few studies have been reported about the relationship between food hypersensitivity and IBS-D, we elucidate the prevalence of serological food hypersensitivity in patients with IBS-D and the characteristics of gastrointestinal symptoms and serum cytokine profiles in patients with IBS-D and serological food hypersensitivity.

Methods

Immunoglobulin E (Ig E)-mediated serological food hypersensitivity and serum cytokine levels were evaluated using the multiple allergen simultaneous test evaluating food allergen-specific serum IgE and Luminex Milliplex Panel containing multiple fluorescence-labeled beads. Class 2 or above was considered as IgE-mediated food hypersensitivity positive. The gastrointestinal symptom rating scale was used to evaluate symptoms.

Results

We enrolled 92 subjects, including 60 with IBS-D and 32 healthy controls. The percentages of patients with IgE-mediated serological food hypersensitivity were not significantly different between the groups (controls = 28.1% and IBS-D = 33.3%). Serum IL-1β, IL-6, IL-8, macrophage inflammatory protein-1alpha, and TNF-α levels were higher in patients with IBS-D than in controls. Serum concentration of TNF-α (43.4 vs 21.8 pg/mL, P = 0.009) was higher in patients with IBS-D without IgE-mediated serological food hypersensitivity than those with food hypersensitivity.

Conclusions

One-third of Japanese patients with IBS-D showed IgE-mediated serological food hypersensitivity. The serum cytokine profile differed and was characterized by lower inflammatory cytokine levels in IBS-D with IgE-mediated serological food hypersensitivity. Serological test regarding IgE-mediated food hypersensitivity can detect a certain cluster of IBS-D.

Current insights into the innate immune system dysfunction in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional bowel disorder associated with abdominal pain and alterations in bowel habits. The presence of IBS greatly impairs patients' quality of life and imposes a high economic burden on the community; thus, there is intense pressure to reveal its elusive pathogenesis. Many etiological mechanisms have been implicated, but the pathophysiology of the syndrome remains unclear. As a result, novel drug development has been slow and no pharmacological intervention is universally accepted. A growing evidence implicates the role of low-grade inflammation and innate immune system dysfunction, although contradictory results have frequently been presented. Mast cells (MC), eosinophils and other key immune cells together with their mediators seem to play an important role, at least in subgroups of IBS patients. Cytokine imbalance in the systematic circulation and in the intestinal mucosa may also characterize IBS presentation. Toll-like receptors and their emerging role in pathogen recognition have also been highlighted recently, as dysregulation has been reported to occur in patients with IBS. This review summarizes the current knowledge regarding the involvement of any immunological alteration in the development of IBS. There is substantial evidence to support innate immune system dysfunction in several IBS phenotypes, but additional studies are required to better clarify the underlying pathogenetic pathways. IBS heterogeneity could potentially be attributed to multiple causes that lead to different disease phenotypes, thus explaining the variability found between study results.

Increased intestinal mucosal leptin levels in patients with diarrhea-predominant irritable bowel syndrome

AIM

To measure the leptin levels in patients with diarrhea-predominant irritable bowel syndrome (IBS-D) and analyze the relationship of leptin with clinical features, visceral sensitivity, mast cells, and nerve fibers.

METHODS

Forty-two patients with IBS-D fulfilling the Rome III criteria and 20 age- and sex-matched healthy controls underwent clinical and psychological evaluations using validated questionnaires (including IBS Symptom Severity Scale, IBS-specific Quality of Life, Hamilton Anxiety Scale, and Hamilton Depression Scale), along with colonoscopy, colonic mucosal biopsy, and visceral sensitivity testing. Serum leptin levels were assayed using enzyme-linked immunosorbent assay. Mucosal leptin expression and localization were evaluated using immunohistochemistry and immunofluorescence. Mucosal leptin mRNA levels were quantified using quantitative real-time reverse transcription polymerase chain reaction. Mast cell counts and activation rates were investigated by toluidine blue staining. Correlation analyses between these parameters were performed.

RESULTS

There were no statistically significant differences in age, gender, or body mass index between the IBS-D group and the control group. The median IBS Symptom Severity Scale score in the IBS-D group was 225.0 (range, 100-475). IBS-D patients had significantly increased anxiety [IBS-D: median, 6.5; interquartile range (IQR), 3.3; control: median, 2.0; IQR, 2.0; P < 0.001] and depression (IBS-D: median, 7.0; IQR, 3.0; control: median, 3.0; IQR, 2.0; P < 0.001) scores. IBS-D patients had significantly lower first sensation threshold (IBS-D: median, 50.6; IQR, 25.9; control: median, 80.5; IQR, 18.6; P < 0.001), defecation sensation threshold (IBS-D: median, 91.5; IQR, 29.3; control: median, 155.0; IQR, 21.1; P < 0.001) and maximum tolerable threshold (IBS-D: median, 163.2; IQR, 71.2; control: median, 226.2; IQR, 39.3; P < 0.001). Mucosal leptin expression, as reflected by integrated optical density (IBS-D: median, 4424.71; IQR, 4533.63; control: median, 933.65; IQR, 888.10; P < 0.001), leptin mRNA expression (IBS-D: median, 1.1226; IQR, 1.6351; control: median, 0.8947; IQR, 0.4595; P = 0.009), and mast cell activation rate (IBS-D: median, 71.2%; IQR, 12.9%; control group: median, 59.4%; IQR, 18.88%; P < 0.001) were significantly increased in IBS-D patients. The colocalization of leptin and leptin receptors was observed on mast cells and PGP9.5-positive nerve fibers in the intestinal mucosa. Also, leptin expression was positively correlated with anxiety, depression, and the mast cell activation rate, but negatively correlated with the defecation sensation threshold and the maximum tolerance threshold during visceral sensitivity testing (adjusted P < 0.0038).

CONCLUSION

Increased levels of mucosal leptin may interact with mast cells and the nervous system to contribute to the pathogenesis of IBS-D.

Review article: transient receptor potential channels as possible therapeutic targets in irritable bowel syndrome

BACKGROUND

Abdominal pain in irritable bowel syndrome (IBS) remains challenging to treat effectively. Researchers have attempted to elucidate visceral nociceptive processes in order to guide treatment development. Transient receptor potential (TRP) channels have been implied in the generation (TRPV1, TRPV4, TRPA1) and inhibition (TRPM8) of visceral pain signals. Pathological changes in their functioning have been demonstrated in inflammatory conditions, and appear to be present in IBS as well.

AIM

To provide a comprehensive review of the current literature on TRP channels involved in visceral nociception. In particular, we emphasise the clinical implications of these nociceptors in the treatment of IBS.

METHODS

Evidence to support this review was obtained from an electronic database search via PubMed using the search terms "visceral nociception," "visceral hypersensitivity," "irritable bowel syndrome" and "transient receptor potential channels." After screening the abstracts the articles deemed relevant were cross-referenced for additional manuscripts.

RESULTS

Recent studies have resulted in significant advances in our understanding of TRP channel mediated visceral nociception. The diversity of TRP channel sensitization pathways is increasingly recognised. Endogenous TRP agonists, including poly-unsaturated fatty acid metabolites and hydrogen sulphide, have been implied in augmented visceral pain generation in IBS. New potential targets for treatment development have been identified (TRPA1 and TRPV4,) and alternative means of affecting TRP channel signalling (partial antagonists, downstream targeting and RNA-based therapy) are currently being explored.

CONCLUSIONS

The improved understanding of mechanisms involved in visceral nociception provides a solid basis for the development of new treatment strategies for abdominal pain in IBS.