Irritable Bowel Syndrome: Straightening the road from the Rome criteria

Metabolic biomarkers in irritable bowel syndrome diagnosis

Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) disorder characterized by altered bowel habits and abdominal discomfort during defecation. It significantly impacts life quality and work productivity for those affected. Global data suggests a slightly higher prevalence in females than in males. Today, unambiguous diagnosis of IBS remains challenging due to the absence of a specific biochemical, histopathological, or radiological test. Current diagnosis relies heavily on thorough symptom evaluation. Efforts by the Rome committees have established standardized diagnostic criteria (Rome I-IV), improving consistency and clinical applicability. Recent studies in this framework, seem to have successfully employed metabolomics techniques to identify distinct metabolite profiles in breath and stool samples of IBS patients, differentiating them from healthy controls and those with other functional GI disorders, such as inflammatory bowel disease (IBD). Building on this success, researchers are investigating the presence of similar metabolites in easily accessible biofluids such as urine, potentially offering a less invasive diagnostic approach. Accordingly, this review focuses on key metabolites specifically detected in IBS patients' biological specimens, with a focus on urinary metabolites, using various methods, particularly mass spectrometry (MS)-based techniques, including gas chromatography-MS (GC-MS), liquid chromatography-tandem MS (LC-MS/MS), and capillary electrophoresis-MS (CE-MS) metabolomics assays. These findings may make provision for a new set of non-invasive biomarkers for IBS diagnosis and management.

Assessing the relationship between gut microbiota and irritable bowel syndrome: a two-sample Mendelian randomization analysis

BACKGROUND

Growing evidence has suggested that gut microbiota is closely related to the risk of irritable bowel syndrome (IBS), but whether there is a causal effect remains unknown. We adopted a Mendelian randomization (MR) approach to evaluate the potential causal relationships between gut microbiota and the risk of IBS.

METHODS

Genetic instrumental variables for gut microbiota were identified from a genome-wide association study (GWAS) of 18,340 participants. Summary statistics of IBS were drawn from a GWAS including 53,400 cases and 433,201 controls. We used the inverse-variance weighted (IVW) method as the primary analysis. To test the robustness of our results, we further performed the weighted-median method, MR-Egger regression, and MR pleiotropy residual sum and outlier test. Finally, reverse MR analysis was performed to evaluate the possibility of reverse causation.

RESULTS

We identified suggestive associations between three bacterial traits and the risk of IBS (odds ratio (OR): 1.08; 95% confidence interval (CI): 1.02, 1.15; p = 0.011 for phylum Actinobacteria; OR: 0.95; 95% CI: 0.91, 1.00; p = 0.030 for genus Eisenbergiella and OR: 1.10; 95% CI: 1.03, 1.18; p = 0.005 for genus Flavonifractor). The results of sensitivity analyses for these bacterial traits were consistent. We did not find statistically significant associations between IBS and these three bacterial traits in the reverse MR analysis.

CONCLUSIONS

Our systematic analyses provide evidence to support a potential causal relationship between several gut microbiota taxa and the risk of IBS. More studies are required to show how the gut microbiota affects the development of IBS.

Fecal Calprotectin Elevations Associated with Food Intolerance/Malabsorption Are Significantly Reduced with Targeted Diets

Inflammatory bowel disease (IBD) involves two clinically defined entities, namely Crohn's disease and ulcerative colitis. Fecal calprotectin (FCAL) is used as a marker to distinguish between organic IBD and functional bowel disease in disorders of the irritable bowel syndrome (IBS) spectrum. Food components may affect digestion and cause functional abdominal disorders of the IBS spectrum. In this retrospective study, we report on FCAL testing to search for IBD in 228 patients with disorders of the IBS spectrum caused by food intolerances/malabsorption. Included were patients with fructose malabsorption (FM), histamine intolerance (HIT), lactose intolerance (LIT), and H. pylori infection. We found elevated FCAL values in 39 (17.1%) of 228 IBS patients with food intolerance/malabsorption and H. pylori infection. Within these, fourteen patients were lactose intolerant, three showed fructose malabsorption, and six had histamine intolerance. The others had combinations of the above conditions: five patients had LIT and HIT, two patients had LIT and FM, and four had LIT and H. pylori. In addition, there were individual patients with other double or triple combinations. In addition to LIT, IBD was suspected in two patients due to continuously elevated FCAL, and then found via histologic evaluation of biopsies taken during colonoscopy. One patient with elevated FCAL had sprue-like enteropathy caused by the angiotensin receptor-1 antagonist candesartan. When screening for study subjects concluded, 16 (41%) of 39 patients with initially elevated FCAL agreed to voluntarily control FCAL measurements, although symptom-free and -reduced, following the diagnosis of intolerance/malabsorption and/or H. pylori infection. After the initiation of a diet individualized to the symptomatology and eradication therapy (when H. pylori was detected), FCAL values were significantly lowered or reduced to be within the normal range.

Chaihu-Guizhi-Ganjiang Decoction is more efficacious in treating irritable bowel syndrome than Dicetel according to metabolomics analysis

Background

Chaihu-Guizhi-Ganjiang Decoction (CGGD) is a traditional Chinese medicine (TCM) prescription used to treat viral influenza. There is evidence that CGGD can be used to treat irritable bowel syndrome (IBS) but the potential mechanism of action and metabolites produced upon CGGD treatment remains elusive.

Methods

Patients with IBS were treated with pinaverium bromide (Dicetel™) and then CGGD after a washout period of 1 week. Both treatments lasted for 30 days. The efficacy and changes of metabolites in plasma after the two treatments were compared. Plasma samples were acquired before and after each treatment, and untargeted metabolics analysis was performed.

Results

Efficacy was measured according to the Rome IV criteria and TCM theory. Our results indicated that CGGD showed significantly better efficacy than Dicetel in the treatment of IBS utilizing each criterion. CGGD exerted greater effects on plasma metabolism than Dicetel. Dicetel treatment led to increased tryptophan metabolism (increased levels of 5-Hydroxyindoleacetaldehyde) and increased protein metabolism (increased levels of L-arginine). CGGD treatment significantly (p < 0.05) increased carnitine metabolism, with elevated levels of L-carnitine and acylcarnitine in plasma. Such changes in these metabolites could exert effects against IBS by improving gastrointestinal motility and suppressing pain, depression, and inflammation.

Conclusions

CGGD appeared to be more efficacious than Dicetel for treating patients with IBS. The findings provide a sound support for the underlying biomolecular mechanism of CGGD in the prevention and treatment of IBS.

Effect of oat or rice flour on pulse-induced gastrointestinal symptoms and breath hydrogen in subjects sensitive to pulses and controls - a randomised cross-over trial with two parallel groups

Pulses are healthy and sustainable but induce gut symptoms in people with a sensitive gut. Oats, on the contrary, have no fermentable oligo- di-, monosaccharides and polyols compounds and are known for the health effects of their fibres. This 4-day cross-over trial investigated the effects of oat and rice flour ingested with pulses on gut symptoms and exhaled gases (4th day only) in subjects with a sensitive gut or IBS (n 21) and controls (n 21). The sensitive group perceived more symptoms after both meals than controls (P = 0·001, P = 0·001). Frequency, intensity or quality of the symptoms did not differ between meals during the first 3 d in either group. More breath hydrogen was produced after an oat than rice containing meal in both groups (AUC, P = 0·001, P = 0·001). No between-group difference was seen in breath gases. During day 4, both sensitive and control groups perceived more symptoms after the oat flour meal (P = 0·001, P = 0·0104, respectively) as mainly mild flatulence. No difference in moderate or severe symptoms was detected. Increased hydrogen production correlated to a higher amount of perceived flatulence after the oat flour meal in both the sensitive and the control groups (P = 0·042, P = 0·003, respectively). In summary, ingestion of oat flour with pulses increases breath hydrogen levels compared with rice flour, but gastrointestinal symptoms of subjects sensitive to pulses were not explained by breath hydrogen levels. Additionally, consumer mindsets towards pulse consumption and pulse-related gut symptoms were assessed by an online survey, which implied that perceived gut symptoms hinder the use of pulses in sensitive subjects.

Belgian consensus on irritable bowel syndrome

BACKGROUND

Irritable bowel syndrome (IBS) is characterised by recurrent abdominal pain related to defaecation or associated with altered stool frequency or consistency. Despite its prevalence, major uncertainties in the diagnostic and therapeutic management persist in clinical practice.

METHODS

A Delphi consensus was conducted by 20 experts from Belgium, and consisted of literature review and voting process on 78 statements. Grading of recommendations, assessment, development and evaluation criteria were applied to evaluate the quality of evidence. Consensus was defined as > 80 % agreement.

RESULTS

Consensus was reached for 50 statements. The Belgian consensus agreed as to the multifactorial aetiology of IBS. According to the consensus abdominal discomfort also represents a cardinal symptom, while bloating and abdominal distension often coexist. IBS needs subtyping based on stool pattern. The importance of a positive diagnosis, relying on history and clinical examination is underlined, while additional testing should remain limited, except when alarm features are present. Explanation of IBS represents a crucial part of patient management. Lifestyle modification, spasmolytics and water-solube fibres are considered first-line agents. The low FODMAP diet, selected probiotics, cognitive behavioural therapy and specific treatments targeting diarrhoea and constipation are considered appropriate. There is a consensus to restrict faecal microbiota transplantation and gluten-free diet, while other treatments are strongly discouraged.

CONCLUSIONS

A panel of Belgian gastroenterologists summarised the current evidence on the aetiology, symptoms, diagnosis and treatment of IBS with attention for the specificities of the Belgian healthcare system.

Quality of life and sleep in individuals with irritable bowel syndrome according to different diagnostic criteria and inflammatory bowel diseases: A comparison using data from a population-based survey

BACKGROUND

A proportion of irritable bowel syndrome (IBS) affected patients does not fulfil Rome criteria despite considerable impairment similarly to that in patients with organic gastrointestinal diseases.This investigation aims to examine differences regarding Mental (MQoL), Physical Quality of Life (PQoL), and sleep between IBS according to Rome III (IBS Rome), clinically defined IBS, inflammatory bowel diseases (IBD), and non-IBS/non-IBD individuals.

METHODS

Data from SHIP-Trend (Study of Health in Pomerania, 2008-2012), a population-based cohort study in Germany, were used.

RESULTS

Response was 50.1% (N = 4420). Prevalence was 3.5% for IBS Rome (95% confidence interval (CI): 3.0 - 4.1%, n = 148), 0.6% for clinically defined IBS (CI: 0.4 - 0.9%, n = 27), and 0.8% for IBD (CI: 0.6 - 1.1%, n = 34). Individuals with IBS Rome (4.54 (CI: -5.92; -3.17)) and clinically defined IBS (4.69 (CI: -7.82; -1.56)) had lower scores for MQoL compared to the non-IBS/non-IBD group. PQoL scores were lowered in IBS Rome (6.39 (CI: -7.89; -4.88)) and IBD (5.37 (CI: -8.51; -2.22)), but not in clinically defined IBS compared to the non-IBS/non-IBD group. IBS Rome was the only gastroenterological condition with higher odds of sleeping problems (odds ratio (OR) "falling asleep": 1.74; CI: 1.29; 2.36; OR "remaining asleep": 1.73; CI: 1.26; 2.38).

CONCLUSIONS

IBS Rome is associated with reduced MQoL, PQoL, and sleep problems. Clinically defined IBS is associated only with reduced MQoL. Heterogeneity within IBS affected patients should be considered in clinical routine and screening for daily life impairment should be performed.

Effect of Bifidobacterium longum 35624 on disease severity and quality of life in patients with irritable bowel syndrome

BACKGROUND

Bifidobacterium longum 35624 has shown efficacy in improving irritable bowel syndrome (IBS) symptoms compared with placebo in double-blind randomized studies. However, few data are available from real-life clinical practice or from studies that used Rome IV criteria to diagnose IBS.

AIM

To assess the effect of B. longum 35624 on IBS severity and quality of life in a real-life setting.

METHODS

From November 2018 to January 2020, 278 patients with IBS (according to Rome IV criteria) were enrolled in a prospective, open-label, multicenter observational study by private practice gastroenterologists to received one capsule of B. longum 35624 (10⁹ colony-forming units) per day for 30 d. Participation in the study was independently proposed to patients during spontaneous consultations. Disease severity (assessed by the IBS severity scoring system) and patient quality of life (assessed by the IBS quality of life questionnaire) were compared between the inclusion visit (baseline) and the visit at the end of 30 d of treatment. The characteristics of patients were described at baseline. Continuous variables comparisons between inclusion and end-of-treatment visits were performed using the t-test and Kruskal-Wallis test. Categorical variables comparisons were performed using the χ2 test.

RESULTS

A total of 233 patients, with a mean age of 51.4 years and composed of 71.2% women, were included in the study. Of these patients, 48.1% had moderate IBS and 46.4% had severe IBS. After a 30-d treatment period with one B. longum 35624 capsule per day, a significant decrease in IBS severity was observed compared to baseline (mean ± SD, IBS severity scoring system scores: 208 ± 104 vs 303 ± 81, P < 0.001) and 57% of patients moved to lower severity categories or achieved remission. The quality of life of patients was also improved by the treatment (IBS Quality of Life questionnaire score: 68.8 ± 20.9 vs 60.2 ± 20.5; P < 0.001) and 63.8% of patients were satisfied with the treatment.

CONCLUSION

Thirty days of treatment with B. longum 35624 reduces disease severity and improves the quality of life of patients with IBS, particularly those with the most severe forms of IBS.

Prevalence, clinical characteristics, and management of irritable bowel syndrome in Vietnam: A scoping review

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders worldwide. Its prevalence varies significantly from country to country, largely due to heterogeneity in the available data. Recent studies show that the prevalence of IBS in Asia is on the rise. However, there are very limited data regarding its prevalence in the Vietnamese population. This review aims to offer an overview of the prevalence and clinical characteristics of IBS in the Vietnamese population; and to discuss the current management of IBS in Vietnam-taking into account the available medical resources and the local spectrum of lower gastrointestinal disorders that may mimic IBS.

Diagnosis and Treatment of Irritable Bowel Syndrome: A Review

IMPORTANCE

The prevalence of irritable bowel syndrome (IBS) in the United States is between 7% and 16%, most common in women and young people, with annual direct costs estimated at more than $1 billion dollars in the United States. Traditionally, the diagnosis of IBS has been based on the positive identification of symptoms that correlate with several different syndromes associated with disorders such as IBS diarrhea, IBS constipation, functional diarrhea, functional constipation, chronic functional abdominal pain, or bloating. Several peripheral and central mechanisms initiate gastrointestinal motor and sensory dysfunctions leading to IBS symptoms. Those dysfunctions may require evaluation in patients whose symptoms do not respond to first-line treatments.

OBSERVATIONS

Validation studies of consensus symptom-based criteria have identified deficiencies that favor a simpler identification of the predominant symptoms of abdominal pain, bowel dysfunction, and bloating and exclusion of alarm symptoms such as unintentional weight loss, rectal bleeding, or recent change in bowel function. Symptom-based diagnosis of IBS is enhanced with additional history for symptoms of somatoform and psychological disorders and alarm symptoms, physical examination including digital rectal examination, and screening tests to exclude organic disease (by measuring hemoglobin and C-reactive protein concentrations). The initial treatment plan should include patient education, reassurance, and first-line treatments such as fiber and osmotic laxatives for constipation, opioids for diarrhea, antispasmodics for pain and for management of associated psychological disorders. For patients who do not respond to those IBS treatments, testing for specific functional disorders may be required in a minority of patients with IBS. These disorders include rectal evacuation disorder, abnormal colonic transit, and bile acid diarrhea. Their identification is followed by individualized treatment, such as pelvic floor retraining for rectal evacuation disorders, sequestrants for bile acid diarrhea, and secretory agents for constipation, although there is only limited evidence that this individualized management approach is effective.

CONCLUSIONS AND RELEVANCE

Advances in the identification of specific dysfunctions as causes of individual symptoms in the "IBS spectrum" leads to the potential to enhance the diagnosis and management of symptoms for the majority of patients for whom first-line therapies of IBS and management of comorbid psychological disorders are insufficient.

Obesity Exacerbates Irritable Bowel Syndrome-Related Sleep and Psychiatric Disorders in Women With Polycystic Ovary Syndrome

BACKGROUND/OBJECTIVES

Polycystic ovary syndrome (PCOS) and irritable bowel syndrome (IBS) share similar clinical and psychosocial features. We aimed to investigate the clinical characteristics of IBS in women with PCOS, and its relationship with obesity, metabolic and hormonal profiles, as well as sleep and psychiatric disorders.

SUBJECTS/METHODS

This is a cross-sectional case-control study of 431 untreated women with PCOS and 259 healthy volunteers. All participants were assessed with a comprehensive clinical evaluation and two questionnaires: the Athens Insomnia Scale (AIS) and the Brief Symptom Rating Scale (BSRS-5). IBS was diagnosed using the Rome III criteria. Obesity was defined as a BMI ≥30 kg/m². Anthropometric measurements, metabolic, hormonal profiles, and psychosocial morbidities were compared.

RESULTS

Women with PCOS were more likely to have IBS (10.7% vs 5.8%, p=0.029) and obesity (29% vs 4%, p<0.001) than healthy volunteers. Mixed-type IBS (IBS-M) was the most common subtype (74%) among patients with PCOS and IBS. There was a higher prevalence of psychiatric morbidities (total BSRS-5 score ≥10) in women with PCOS than in healthy women (11.4% vs 3.5%, p<0.001). Women with PCOS and IBS were more likely to have sleep difficulties (67.4% vs 30.9%, p<0.001) and psychiatric morbidities (21.7% vs 10.1%, p=0.019) than those without IBS. Anthropometrics, metabolic and hormonal profiles were similar between PCOS women with and without IBS. Among women with PCOS, those with both IBS and obesity had the highest risk of developing sleep difficulties (odds ratio: 5.91; 95% confidence interval: 1.77-19.77) and psychiatric distress (odds ratio: 4.39; 95% confidence interval: 1.26-15.29) than those without.

CONCLUSION

Women with PCOS have increased IBS, obesity, sleep and psychiatric disturbances. The presence of IBS in PCOS women is associated with sleep and psychiatric disorders. The coexistence of obesity and IBS exacerbates sleep difficulties and psychiatric distress. Screening and management of IBS and obesity might be warranted to improve sleep and psychiatric disturbances in women with PCOS.