Effects of PAR2 Gene Knockout on Visceral Sensitivity, Stress Behaviors, and Colonic Electrical Activities in Irritable Bowel Syndrome

BACKGROUND

Irritable bowel syndrome (IBS) could seriously affect the patient's health quality by its recurrence. There is a great medical and social need to explore the mechanisms and new treatment strategies of IBS.

OBJECTIVE

To explore the influence of protease-activated receptor 2 (PAR2) gene knockout on IBS visceral sensitivity, stress behaviors, and colonic electrical activities.

METHODS

The PAR2 gene knockout and IBS model rats were generated and divided into PAR2+/+ wild control (WC) group, PAR2+/+ wild IBS model (WM) group, PAR2-/- knockout control (KC) group and PAR2-/- knockout IBS model (KM) group. The stress behaviors scores, minimum rectal fluid injection capacity threshold value of abdominal withdrawal reflex (AWR) = 3, and the colonic electrical activities indexes were recorded and the experimental results were analyzed statistically.

RESULTS

(1) PAR2 gene deletion and IBS models were successfully generated. (2) The scores of aggressive and exploratory behaviors in WM and KM groups were higher than WC and KC groups (p < 0.05). The grooming behavior scores in WC and KC groups were higher than the WM and KM groups (p < 0.05). WM group had the highest aggressive and exploratory behavior scores; WC group had the highest grooming behavior scores. (3) The minimum rectal fluid injection capacity threshold value of AWR = 3 in WM and KM groups were lower than WC and KC groups (p < 0.05); WM group had the lowest value. (4) The maximum amplitude and wave frequency of colonic fast and slow waves in WM and WC groups were greater than in the KM and KC groups, respectively (p < 0.05). The amplitude index and number of colonic contraction waves in WM and KM groups were greater than the WC and KC groups (p < 0.05). Colonic electrical activity indexes were highest in the WM group.

CONCLUSIONS

The PAR2 gene deletion could have a beneficial effect on visceral sensitivity, stress behaviors and colonic electrical activities in rats with IBS.

Best Parameters of Heart Rate Variability for Assessing Autonomic Responses to Brief Rectal Distention in Patients with Irritable Bowel Syndrome

Heart rate variability (HRV) has been used to measure autonomic nervous system (ANS) activity noninvasively. The purpose of this study was to identify the most suitable HRV parameters for ANS activity in response to brief rectal distension (RD) in patients with Irritable Bowel Syndrome (IBS). IBS patients participated in a five-session study. During each visit, an ECG was recorded for 15 min for baseline values and during rectal distension. For rectal distension, a balloon was inflated in the rectum and the pressure was increased in steps of 5 mmHg for 30 s; each distension was followed by a 30 s rest period when the balloon was fully deflated (0 mmHg) until either the maximum tolerance of each patient was reached or up to 60 mmHg. The time-domain, frequency-domain and nonlinear HRV parameters were calculated to assess the ANS activity. The values of each HRV parameter were compared between baseline and RD for each of the five visits as well as for all five visits combined. The sensitivity and robustness/reproducibility of each HRV parameter were also assessed. The parameters included the Sympathetic Index (SI); Root Mean Square of Successive Differences (RMSSD); High-Frequency Power (HF); Low-Frequency Power (LF); Normalized HF Power (HFn); Normalized LF Power (LFn); LF/HF; Respiratory Sinus Arrhythmia (RSA); the Poincare Plot's SD1, SD2 and their ratio; and the pNN50, SDSD, SDNN and SDNN Index. Data from 17 patients were analyzed and compared between baseline and FD and among five sessions. The SI was found to be the most sensitive and robust HRV parameter in detecting the ANS response to RD. Out of nine parasympathetic parameters, only the SDNN and SDNN Index were sensitive enough to detect the parasympathetic modulation to RD during the first visit. The frequency-domain parameters did not show any change in response to RD. It was also observed that the repetitive RD in IBS patients resulted in a decreased autonomic response due to habituation because the amount of change in the HRV parameters was the highest during the first visit but diminished during subsequent visits. In conclusion, the SI and SDNN/SDNN Index are most sensitive at assessing the autonomic response to rectal distention. The autonomic response to rectal distention diminishes in repetitive sessions, demonstrating the necessity of randomization for repetitive tests.

Prevalence of Fibromyalgia and Chronic Fatigue Syndrome among Individuals with Irritable Bowel Syndrome: An Analysis of United States National Inpatient Sample Database

Background and Aim: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder associated with other somatic disorders. We studied the prevalence and predictors of fibromyalgia and chronic fatigue syndrome (CFS) in IBS patients. Methods: We used the National Inpatient Sample and included hospitalization of individuals with IBS, using ICD-10 codes, from 2016-2019. The prevalence and predictors of fibromyalgia and CFS in IBS patients were studied. Univariate and multivariate patient- and hospital-level regression models were used to calculate the adjusted odds of fibromyalgia and CFS in the IBS patient population. Results: Of 1,256,325 patients with an ICD-10 code of IBS included in the study, 10.73% (134,890) also had ICD-10 codes for fibromyalgia and 0.42% (5220) for CFS. The prevalence of fibromyalgia and CFS was significantly higher in IBS patients (adjusted odds ratio (AOR) 5.33, 95% confidence interval (CI) 5.24-5.41, p < 0.001, and AOR 5.40, 95% CI 5.04-5.78, p < 0.001, respectively) compared to the general adult population without IBS. IBS-diarrhea, IBS-constipation, and IBS-mixed types were independently associated with increased odds of fibromyalgia and CFS. Increasing age (AOR 1.02, 95% CI 1.01-1.04, p 0.003; AOR 1.02, 95% CI 1.01-1.03, p 0.001), female gender (AOR 11.2, 95% CI 11.1-11.4, p < 0.001; AOR 1.86, 95% CI 1.78-1.93, p < 0.001) and white race (AOR 2.04, 95% CI 1.95-2.12, p < 0.001; AOR 1.69, 95% CI 1.34-2.13, p < 0.001) were independent predictors of increased odds of fibromyalgia and CFS, respectively. Conclusions: It appears that IBS is associated with an increased prevalence of somatic disorders such as fibromyalgia and CFS.

Gut Dysbiosis in Irritable Bowel Syndrome: A Narrative Review on Correlation with Disease Subtypes and Novel Therapeutic Implications

Irritable bowel syndrome (IBS) is a prevalent functional gastrointestinal disorder characterized by chronic abdominal pain and altered bowel habits. It can be subclassified in different subtypes according to the main clinical manifestation: constipation, diarrhea, mixed, and unclassified. Over the past decade, the role of gut microbiota in IBS has garnered significant attention in the scientific community. Emerging research spotlights the intricate involvement of microbiota dysbiosis in IBS pathogenesis. Studies have demonstrated reduced microbial diversity and stability and specific microbial alterations for each disease subgroup. Microbiota-targeted treatments, such as antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation, and even diet, offer exciting prospects for managing IBS. However, definitive conclusions are hindered by the heterogeneity of these studies. Further research should focus on elucidating the mechanisms, developing microbiome-based diagnostics, and enabling personalized therapies tailored to an individual's microbiome profile. This review takes a deep dive into the microscopic world inhabiting our guts, and its implications for IBS. Our aim is to elucidate the complex interplay between gut microbiota and each IBS subtype, exploring novel microbiota-targeted treatments and providing a comprehensive overview of the current state of knowledge.

The Effect of Polyphenols, Minerals, Fibers, and Fruits on Irritable Bowel Syndrome: A Systematic Review

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder characterized by abdominal pain, bloating, and changes in bowel habits. Various dietary factors have been implicated in the pathogenesis and management of IBS symptoms. This systematic review aims to evaluate the effects of polyphenols, minerals, fibers, and fruits on the symptoms and overall well-being of individuals with IBS.

MATERIALS AND METHODS

A comprehensive literature search was conducted in several electronic databases, including PubMed, Scopus, and Web of Science. Studies published up until July 2023 were included.

RESULTS

The selected studies varied in terms of study design, participant characteristics, intervention duration, and outcome measures. Overall, the findings suggest that dietary interventions involving polyphenols, minerals, fibers, and fruits can have a positive impact on IBS symptoms. Dietary fiber supplementation, particularly soluble fiber, has been associated with reduced bloating and enhanced stool consistency.

CONCLUSIONS

This systematic review provides evidence supporting the beneficial effects of polyphenols, minerals, fibers, and fruits in IBS patients. These dietary components hold promise as complementary approaches for managing IBS symptoms. However, due to the heterogeneity of the included studies and the limited number of high-quality randomized controlled trials, further well-designed trials are warranted to establish the optimal dosages, duration, and long-term effects of these interventions. Understanding the role of specific dietary components in IBS management may pave the way for personalized dietary recommendations and improve the quality of life for individuals suffering from this complex disorder.

Misinterpreting Diarrhea-Predominant Irritable Bowel Syndrome and Functional Diarrhea: Pathophysiological Highlights

Irritable bowel syndrome with predominant diarrhea (IBS-D) and functional diarrhea (FD) are disorders of gut-brain interaction characterized by recurring symptoms which have a serious impact on the patient's quality of life. Their pathophysiology is far from being completely understood. In IBS-D growing evidence suggests that bile acid malabsorption (BAM) could be present in up to 30% of patients. Microscopic colitis (MC) is a well-known cause of watery diarrhea and some patients, at first, can be diagnosed as IBS-D or FD. Both BAM and MC are often responsible for the lack of response to conventional treatments in patients labelled as "refractory". Moreover, because BAM and MC are not mutually exclusive, and can be found in the same patient, they should always be considered in the diagnostic workout when a specific treatment for BAM or MC is unsatisfactory. In the present review the possible shared pathogenetic mechanisms between BAM and MC are discussed highlighting how MC can induce a secondary BAM. Moreover, a brief overview of the current literature regarding the prevalence of their association is provided.

The Socioeconomic Impact of Irritable Bowel Syndrome: An Analysis of Direct and Indirect Health Care Costs

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is associated with substantial costs to society. Extensive data on direct costs (health care consumption) and indirect costs (health-related productivity loss) are lacking. Hence, we examined the socioeconomic costs of IBS and assessed which patient characteristics are associated with higher costs.

METHODS

Cross-sectional data from 3 Rome-defined Dutch IBS patient cohorts (n = 419) were collected. Bootstrapped mean direct and indirect costs were evaluated per patient with IBS using validated questionnaires (ie, medical cost questionnaire and productivity cost questionnaire, respectively). Multivariable regression analyses were performed to identify variables associated with higher costs.

RESULTS

Quarterly mean total costs per patient were €2.156 (95% confidence interval (CI), €1793-€2541 [$2444]), consisting of €802 (95% CI, €625-€1010 [$909]) direct costs and €1.354 (95% CI, €1072-€1670 [$1535]) indirect costs. Direct costs consisted primarily of health care professional consultations, with costs related to gastrointestinal clinic visits accounting for 6% and costs related to mental health care visits for 20%. Higher direct costs were significantly associated with older age (P = .007), unemployment (P = .001), IBS subtypes other than constipation (P = .033), lower disease-specific quality of life (P = .027), and more severe depressive symptoms (P = .001). Indirect costs consisted of absenteeism (45%), presenteeism (42%), and productivity loss related to unpaid labor (13%) and were significantly associated with the male sex (P = .014) and more severe depressive symptoms (P = .047).

CONCLUSIONS

Productivity loss is the main contributor to the socioeconomic burden of IBS. Direct costs were not predominantly related to gastrointestinal care, but rather to mental health care. Awareness of the nature of costs and contributing patient factors should lead to significant socioeconomic benefits for society.

Diagnosis of Irritable Bowel Syndrome: Primary Care Physicians Compared with Gastroenterologists

Objective: To examine disparities between primary care provider (PCP) and gastroenterologist diagnosis and management of irritable bowel syndrome (IBS).Design: Retrospective cross-sectional study.Setting: A 547-bed quaternary-care hospital within the Loyola University Healthcare System.Participants: 1000 patients aged 18-65 with an ICD-10 diagnosis of IBSMethods: We randomly selected 1000 patients aged 18 to 65 years within the Loyola University Healthcare System's electronic medical record with an ICD-10 diagnosis of IBS. Physician notes and diagnostic results were reviewed for documentation of symptoms fulfilling Rome IV criteria and resolution of symptoms. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of primary diagnoses assigned by PCPs and gastroenterologists were assessed along with number of diagnostic tests ordered.Results: The mean age (SD) was 45 (12) years, and 76.9% were female. Sensitivity of an IBS diagnosis by a PCP was 77.6% (95% CI 73.3-81.9), compared with 60.1% (95% CI 54.7-65.6) for a gastroenterologist. Specificity of an IBS diagnosis by a PCP was 27.5% (95% CI 23.5-31.5), compared with 71.1% (95% CI 64.6-77.5) for a gastroenterologist diagnosis of IBS. A gastroenterologist diagnosis of IBS carried a high PPV (77.3%, 95% CI 72.0-82.6) compared with 44.6% (95% CI 40.7-48.5) for a PCP. Of 180 patients with outcome data, 69.4% had resolution of symptoms at follow-up.Conclusion: The sensitivity of gastroenterologist diagnosis of IBS closely matches the sensitivity of Rome IV criteria in validation studies. The high specificity and PPV of gastroenterologists suggest more cautious diagnosis by gastroenterologists, with PCPs more likely to assign a diagnosis of IBS incorrectly or without sufficient documentation of symptoms fulfilling Rome IV criteria. Reported resolution rates suggest primary care management of IBS is appropriate, but PCPs may benefit from gastroenterologist consultation and diagnostic guidelines for greater specificity in diagnosing IBS.

Nutrition, Physical Activity and Supplementation in Irritable Bowel Syndrome

Irritable Bowel Syndrome (IBS) is a chronic, recurrent functional disorder of the intestine diagnosed based on the Rome IV criteria. Individuals suffering from IBS often associate the severity of their symptoms with the food they consume, leading them to limit the variety of foods they eat and seek information that could help them determine the appropriate selection of dietary items. Clear nutritional recommendations have not been established thus far. NICE recommends a rational approach to nutrition and, if necessary, the short-term implementation of a low FODMAP diet. Currently, the FODMAP diet holds the greatest significance among IBS patients, although it does not yield positive results for everyone affected. Other unconventional diets adopted by individuals with IBS lack supporting research on their effectiveness and may additionally lead to a deterioration in nutritional status, as they often eliminate foods with high nutritional value. The role of physical activity also raises questions, as previous studies have shown its beneficial effects on the physical and mental well-being of every individual, and it can further help alleviate symptoms among people with IBS. Supplementation can be a supportive element in therapy. Attention is drawn to the use of probiotics, vitamin D, and psyllium husk/ispaghula. This review aims to analyze the existing scientific research to determine the impact of various food items, physical activity, and dietary supplementation with specific components through dietary supplements on the course of IBS.

The Impact of a Twelve-Week Moderate Aerobic Exercise Program on Gastrointestinal Symptom Profile and Psychological Well-Being of Irritable Bowel Syndrome Patients: Preliminary Data from a Southern Italy Cohort

Walking is popular moderate-intensity aerobic exercise that improves mental and gastrointestinal (GI) health. It can relieve symptoms associated with irritable bowel syndrome (IBS), e.g., intestinal gas, abdominal distension, and bowel disturbances. This study examined the impact of a moderate-intensity aerobic exercise program on the clinical and psychological parameters of IBS patients. In total, 40 IBS patients (11 males and 29 females; mean age 51.9 ± 7.8 years) participated in a 12-week aerobic exercise program. Participants completed questionnaires assessing GI symptoms, psychological profiles, and quality of life (QoL) before and after the intervention. Field tests, anthropometric measurements, and bioimpedance assessments were also conducted. The present findings confirmed a significant improvement in IBS symptoms after the aerobic exercise program. Bloating was the most common symptom and, together with abdominal pain, was significantly reduced after treatment. Psychological and QoL questionnaires indicated decreased anxiety, depression, somatization, and stress levels. Correlations were found between anxiety/depression and the severity of abdominal pain as well as between stress and the severity of abdominal distension. Moderate-intensity aerobic exercise positively impacted GI symptoms and psychological well-being, complementing dietary and psychological support as a non-pharmacological therapy for the management of IBS. These findings emphasize the importance of alternative approaches for IBS treatment.

The Effects of Agave Fructans in a Functional Food Consumed by Patients with Irritable Bowel Syndrome with Constipation: A Randomized, Double-Blind, Placebo-Controlled Trial

Irritable bowel syndrome displays three different subtypes: constipation (IBS-C), diarrhea (IBS-D), and mixed (IBS-M). Treatment with dietary fiber is used, with consideration given both to the chemical composition of the fiber and to the different subtypes of IBS. The IBS-D subtype is usually treated with a low-FODMAPs diet, whereas the IBS-C subtype suggests prebiotics and probiotics to promote microbiota restoration. The aim of this study was to assess the effects of employing agave fructans as the soluble fiber of a jelly (Gelyfun®gastro) containing 8 g per serving in the IBS-C group (n = 50), using a randomized, double-blind, time-limited trial for four weeks. We evaluated changes in the frequency and types of bowel movements through the Bristol scale, and the improvement of the condition was evaluated using quality of life (IBS-QOL) and anxiety-depression (HADS) scales. The main results were that the number of bowel movements increased by more than 80%, with at least one stool per day from fifteen days onwards, without a laxative effect for the group treated. Finally, the quality of life with the prebiotic jelly was significantly improved compared to the placebo in all specific domains, in addition to significantly reducing anxiety and depression.

Faecal and urine metabolites, but not gut microbiota, may predict response to low FODMAP diet in irritable bowel syndrome

BACKGROUND

The low FODMAP diet (LFD) leads to clinical response in 50%-80% of patients with irritable bowel syndrome (IBS). It is unclear why only some patients respond.

AIMS

To determine if differences in baseline faecal microbiota or faecal and urine metabolite profiles may separate clinical responders to the diet from non-responders allowing predictive algorithms to be proposed.

METHODS

We recruited adults fulfilling Rome III criteria for IBS to a blinded randomised controlled trial. Patients were randomised to sham diet with a placebo supplement (control) or LFD supplemented with either placebo (LFD) or 1.8 g/d B-galactooligosaccharide (LFD/B-GOS), for 4 weeks. Clinical response was defined as adequate symptom relief at 4 weeks after the intervention (global symptom question). Differences between responders and non-responders in faecal microbiota (FISH, 16S rRNA sequencing) and faecal (gas-liquid chromatography, gas-chromatography mass-spectrometry) and urine (1 H NMR) metabolites were analysed.

RESULTS

At 4 weeks, clinical response differed across the 3groups with adequate symptom relief of 30% (7/23) in controls, 50% (11/22) in the LFD group and 67% (16/24) in the LFD/B-GOS group (p = 0.048). In the control and the LFD/B-GOS groups, microbiota and metabolites did not separate responders from non-responders. In the LFD group, higher baseline faecal propionate (sensitivity 91%, specificity 89%) and cyclohexanecarboxylic acid esters (sensitivity 80%, specificity 78%), and urine metabolite profile (Q2 0.296 vs. randomised -0.175) predicted clinical response.

CONCLUSIONS

Baseline faecal and urine metabolites may predict response to the LFD.

Characteristics of ginsenoside Rd-induced effects on rat intestinal contractility with irritable bowel syndrome

Irritable bowel syndrome (IBS) is a very common refractory disease. Its exact pathophysiological mechanism is still unclear. Despite the availability of plentiful drugs to control IBS, most patients do not respond well. Ginsenoside Rd is one of the major active components of Panax ginseng, which has been verified to produce various pharmacological actions. However, the role of ginsenoside Rd in modulating smooth muscle contractility is still undefined. The aim of this study is to investigate the effects of ginsenoside Rd on intestinal contractility and related mechanisms in IBS.

Disordered eating and eating competence in members of online irritable bowel syndrome support groups

BACKGROUND

This study seeks to evaluate eating competence and disordered eating likelihood among members of online support groups for irritable bowel syndrome (IBS) and determine whether eating competence and disordered eating likelihood varies according to IBS symptom severity and subtype.

METHODS

This cross-sectional study is based on an anonymous survey conducted from August to September 2021. Adults with IBS (N = 225) were recruited from online and social media IBS support forums. IBS symptom severity was assessed using the validated IBS Severity Scoring System (IBS-SSS), likelihood of disordered eating was assessed using the validated Eating Attitudes Test (EAT-26), and eating competence was assessed using the validated Satter Eating Competence Inventory (ecSI 2.0™). Multiple linear regression was used to predict EAT-26 total score from IBS-SSS score, age, and IBS subtype. ANOVAs were used to examine the relationships between IBS severity level, IBS subtype, and ecSI 2.0™ total score.

KEY RESULTS

Eating competence among the sample was low at 17% while 27% was classified as likely or very likely disordered eating. IBS severity was positively associated with EAT-26 score (p = 0.011) and ecSI 2.0™ score was significantly lower in the severe IBS group compared to the moderate IBS group (p = 0.016). No relationship was detected between IBS subtype and EAT-26 or ecSI 2.0™ scores.

CONCLUSIONS & INFERENCES

IBS severity was positively associated with disordered eating likelihood and negatively associated with eating competence. This sheds light on the importance of assessing eating competence and screening for disordered eating prior to selecting therapies for patients with IBS, particularly in females with severe symptoms.

Role of Nutrition in Gastroesophageal Reflux, Irritable Bowel Syndrome, Celiac Disease, and Inflammatory Bowel Disease

There remains a paucity of data on the efficacy of nutritional interventions in luminal gastrointestinal disorders. This review appraises the evidence supporting dietary modification in gastroesophageal reflux disease (GERD), irritable bowel syndrome, Celiac disease, and inflammatory bowel disease. Alhough the use of elimination diets; high fat/low carb; low fermentable oligosaccharides, disaccharides, monosaccharides and polyols; and lactose-free diets in GERD have been studied, the evidence supporting their efficacy remains weak and mixed. Patients with GERD should avoid eating within 3 hours of lying recumbent. Studied dietary interventions for disorders of gut-brain interaction include low fermentable oligosaccharides, disaccharides, monosaccharides and polyols and gluten-restricted and lactose-free diets. While all can be effective in carefully, individually selected patients, the evidence for each intervention remains low. In patients with inflammatory bowel disease, enteral nutrition is established in pediatric populations as useful in reducing inflammation and partial enteral nutrition has a growing evidence base for use in adults and children. Specific carbohydrate diets and the Crohn's disease exclusion diet show promising evidence but require further study to validate their efficacy prior to recommendation. Overall, the evidence supporting nutritional therapy across luminal gastrointestinal disorders is mixed and often weak, with few well-designed randomized controlled trials (RCTs) demonstrating consistent efficacy of interventions. RCTs, particularly cross-over RCTs, show potential to compare dietary interventions.

Like clockwork? (Re)imagining rhythms and routines when living with irritable bowel syndrome (IBS)

Temporal trajectories of health, illness and disability-from biographical change to micro-embodied practices within social time-are important strands within medical sociology and disability studies. Drawing upon a UK-based qualitative study using diaries and follow-up interviews to explore everyday life with irritable bowel syndrome (IBS), this article explores routines when living with the condition. It focuses specifically on accounts of routines being anticipated, slowed down and stretched out to accommodate and/or care for bodies, with personal and social rhythms weaved in, out and with each other. Such reflections are told through participants' accounts of knowing routines and rhythms, stretching out and pacing morning routines to care for the body and how everyday practices are reimagined as the body and the social meet. Drawing upon the concept of 'Crip Time' where the social bends to meet with the body, this article seeks to illuminate important intersections between medical sociology and disability studies through accounts of living with IBS. This article demonstrates the entanglement of structural, disabling temporal rhythms and embodied temporalities, through an acknowledgement of routines reimagined. It offers a contribution to both medical sociology and disability studies in reimagining social lives with embodied temporalities in mind.

Pain Catastrophizing and Clinical Outcomes Among Patients Receiving a Novel Cognitive-Behavioral Therapy for Irritable Bowel Syndrome: An Experimental Therapeutics Approach

Irritable bowel syndrome (IBS) is the most common gastrointestinal (GI) condition treated by GI and primary care physicians. Although IBS symptoms (abdominal pain, bowel problems) are generally refractory to medical therapies, consistent research has shown that they improve following cognitive-behavioral therapy (CBT). Notwithstanding empirical support for CBT, there is less research explicating the reasons for why or how it works. Like other pain disorders, the focus on change mechanisms for behavioral pain treatments has focused on pain-specific cognitive-affective processes that modulate pain experience, few of which are more important than pain catastrophizing (PC). The fact that PC changes are seen across treatments of differing theoretical and technical orientation, including CBT, yoga, and physical therapy, suggests that it may be a nonspecific (vs. theory-based) change mechanism akin to therapeutic alliance and treatment expectancy. Therefore, the current study examined change in PC as a concurrent mediator of IBS symptoms severity, global GI symptom improvement, and quality of life among 436 Rome III-diagnosed IBS patients enrolled in a clinical trial undergoing two dosages of CBT versus a nonspecific comparator emphasizing education and support. Results from structural equation modeling parallel process mediation analyses suggest that reduction in PC during treatment are significantly associated with improvement in IBS clinical outcomes through 3-month follow-up. Results from the current study provide evidence that PC may be an important, albeit nonspecific change mechanism, during CBT for IBS. Overall, reducing the emotional unpleasantness of pain through cognitive processes is associated with improved outcomes for IBS.

Fibromyalgia and Irritable Bowel Syndrome Interaction: A Possible Role for Gut Microbiota and Gut-Brain Axis

Fibromyalgia (FM) is a serious chronic pain syndrome, characterised by muscle and joint stiffness, insomnia, fatigue, mood disorders, cognitive dysfunction, anxiety, depression and intestinal irritability. Irritable Bowel Syndrome (IBS) shares many of these symptoms, and FM and IBS frequently co-exist, which suggests a common aetiology for the two diseases. The exact physiopathological mechanisms underlying both FM and IBS onset are unknown. Researchers have investigated many possible causes, including alterations in gut microbiota, which contain billions of microorganisms in the human digestive tract. The gut-brain axis has been proven to be the link between the gut microbiota and the central nervous system, which can then control the gut microbiota composition. In this review, we will discuss the similarities between FM and IBS. Particularly, we will focus our attention on symptomatology overlap between FM and IBS as well as the similarities in microbiota composition between FM and IBS patients. We will also briefly discuss the potential therapeutic approaches based on microbiota manipulations that are successfully used in IBS and could be employed also in FM patients to relieve pain, ameliorate the rehabilitation outcome, psychological distress and intestinal symptoms.

Efficacy of Different Dietary Patterns in the Treatment of Functional Gastrointestinal Disorders in Children and Adolescents: A Systematic Review of Intervention Studies

Functional gastrointestinal disorders (FGIDs) are common in children and adolescents. In recent years, interest in the role of diet in the treatment of FGIDs has increased. Currently, interest focuses on the low-FODMAP diet (LFD), the fructose- or lactose-restricted diet (FRD or LRD), the gluten-free diet (GFD), and the Mediterranean diet (MD). In this review, we focus on the role of these dietary patterns in the FGIDs most commonly diagnosed in clinical practice, namely irritable bowel syndrome (IBS), functional abdominal pain (FAP), functional dyspepsia (FD), and functional constipation (FC). Fifteen clinical trials were systematically reviewed (both RCTs and single-arm clinical trials). We demonstrated the lack of high-quality intervention trials. Based on current evidence, low-FODMAP diet, LRD, FRD, and GFD have no place in daily clinical practice for the management of children and adolescents with FGIDs. Nevertheless, some patients with IBS or RAP may experience some benefit from the use of a low-FODMAP diet or FRD/LRD. Limited data suggest that MD may be promising in the management of FGIDs, especially in IBS patients, but more data are required to investigate the mechanisms of its protective effects.

Tenapanor in the Treatment of Irritable Bowel Syndrome with Constipation: Discovery, Efficacy, and Role in Management

Irritable bowel syndrome (IBS) is a common disorder of gut-brain interaction (DGBI). IBS significantly impacts the quality of life of patients. Since its pathogenesis is unclear and can be multifactorial, it highlights the need for new and improved pharmaceutical drugs that not only improve bowel symptoms, but also address global IBS symptoms, such as abdominal pain. Tenapanor, a recently Food & Drug Administration (FDA)-approved medication for IBS with constipation (IBS-C), is a small molecule inhibitor of the sodium/hydrogen exchanger isoform 3 (NHE₃) that inhibits the absorption of sodium and phosphate in the gastrointestinal tract, resulting in fluid retention and softer stool. Furthermore, tenapanor reduces intestinal permeability to improve visceral hypersensitivity and abdominal pain. Due to its recent approval, tenapanor was not included in the recent IBS guidelines, however, it may be considered for IBS-C patients failing first-line treatment of soluble fiber. In this review article, we aim to provide in-depth information to the reader regarding the design of tenapanor, its development through Phase I, II and III randomized clinical trials, and its role in the treatment of IBS-C.

Fecal microbiota transplant delivered via invasive routes in irritable bowel syndrome: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

Irritable bowel syndrome (IBS) results in significant loss of quality of life. Management guidelines do not recommend fecal microbiota transplant (FMT) for IBS based on weak evidence as refined data is lacking. We performed a systematic review and meta-analysis to ascertain the pooled clinical outcomes of FMT in IBS, delivered via invasive routes.

METHODS

Multiple databases were searched through January 2023 to identify studies that reported on FMT treatment in IBS by invasive routes. Standard meta-analysis methodology using the random-effects model was used. Heterogeneity was assessed by I2% and 95% predication interval.

RESULTS

Five studies were included. As many as 377 IBS patients were assessed, of which 238 received FMT and 139 received placebo. One study used nasojejunal tubes, one esophagogastroduodenoscopy and three colonoscopy for FMT delivery. FMT via colonoscopy was performed as a one-time procedure instilled into the cecum. Two studies used 30 g of stool from a single universal donor and one study used 50-80 g of pooled donor feces. The pooled odds ratio of improvement in IBS symptoms with FMT was significantly better as compared to that of placebo OR = 2.9 (95% CI [1.6-5.2, I2 = 62%, p < 0.001]). This was true for studies that exclusively used colonoscopy (OR = 2.1 [1.1-4.2, p = 0.04]). In the FMT arm, 10 patients (10.6%) reported abdomen pain and worsening of symptoms with bloating and six patients (6.3%) reported diarrhea.

CONCLUSION

FMT delivered via invasive routes, especially colonoscopy, demonstrated significant improvement in IBS symptoms. A single FMT consisting of 30 g or more of single universal donor feces instilled into the cecum is the predominant modality.

Assessment of Self-Reported Executive Function in Patients with Irritable Bowel Syndrome Using a Machine-Learning Framework

Introduction: Irritable bowel syndrome (IBS) is characterized as a disorder of the gut-brain interaction (DGBI). Here, we explored the presence of problems related to executive function (EF) in patients with IBS and tested the relative importance of cognitive features involved in EF. Methods: A total of 44 patients with IBS and 22 healthy controls (HCs) completed the Behavior Rating Inventory of Executive Function (BRIEF-A), used to identify nine EF features. The PyCaret 3.0 machine-learning library in Python was used to explore the data, generate a robust model to classify patients with IBS versus HCs and identify the relative importance of the EF features in this model. The robustness of the model was evaluated by training the model on a subset of data and testing it on the unseen, hold-out dataset. Results: The explorative analysis showed that patients with IBS reported significantly more severe EF problems than the HC group on measures of working memory function, initiation, cognitive flexibility and emotional control. Impairment at a level in need of clinical attention was found in up to 40% on some of these scales. When the nine EF features were used as input to a collection of different binary classifiers, the Extreme Gradient Boosting algorithm (XGBoost) showed superior performance. The working memory subscale was consistently selected with the strongest importance in this model, followed by planning and emotional control. The goodness of the machine-learning model was confirmed in an unseen dataset by correctly classifying 85% of the IBS patients. Conclusions: The results showed the presence of EF-related problems in patients with IBS, with a substantial impact of problems related to working memory function. These results suggest that EF should be part of an assessment procedure when a patient presents other symptoms of IBS and that working memory function should be considered a target when treating patients with the disorder. Further studies should include measures of EF as part of the symptom cluster characterizing patients with IBS and other DGBIs.