Underlying molecular and cellular mechanisms in childhood irritable bowel syndrome

Expert review of child and caregiver critiques of a therapeutic guided imagery therapy mobile application targeting disorders of gut-brain interaction in children

Background

A guided imagery therapy mobile application (GIT App) is a novel platform for treating children with disorders of gut-brain interaction (DGBI). Previous feedback from child/caregiver dyads suggested modifications for our App prototype. However, their feedback had the potential to affect the intervention's efficacy. Thus, we aimed to have their critiques vetted by relevant experts prior to further App refinement.

Objective

Compare expert reviews of the GIT App with end-users' (i.e., child/caregiver dyads') feedback.

Methods

This mixed-methods study with experts included a hands-on App evaluation, a survey assessing usability, and focus groups comparing their perspectives with those previously provided by end-users.

Results

Eight medical and technology experts were enrolled. Their average usability survey score of the GIT App was 69.0 ± 27.7, which was marginally above the 50th percentile. While the expert and end-user usability assessments were generally favorable, both groups agreed that the App's reminder notification feature location was not intuitive, detracting from its usability. Experts agreed with end-users that the App's aesthetics were acceptable and suggested increasing icon and font sizes. Like the end-users, the experts did not achieve consensus regarding the ideal session length or inclusion of background sounds and screen animations. Lastly, the experts agreed with end-users that gamification techniques (e.g., gift cards and virtual badges) would promote user engagement.

Conclusion

An expert review of our therapeutic App revealed findings consistent with end-users and provided insight for modifying the interface and GIT sessions. Based on this experience, we recommend expert vetting of end-user suggestions as a routine checkpoint when developing therapeutic Apps.

The Use of Pictograms in the Evaluation of Functional Abdominal Pain Disorders in Children

OBJECTIVE

To evaluate whether the use of pictograms improves symptom evaluation for children with functional abdominal pain disorders (FAPDs).

STUDY DESIGN

This survey study was conducted in 2 academic centers and included patients aged 8-18 years visiting the outpatient clinic for FAPD symptom evaluation. Patients were randomized to fill out the questionnaire without or with accompanying pictograms to assess gastrointestinal symptoms. Afterwards, patients underwent clinical health assessment by the healthcare professional (HCP). Subsequently, the HCP filled out the same questionnaire without pictograms, while blinded to the questionnaire completed by the patient. Primary outcome was the level of agreement between identified symptoms as assessed by patients and HCP.

RESULTS

We included 144 children (questionnaire without accompanying pictograms [n = 82] and with accompanying pictograms [n = 62]). Overall agreements rates were not significantly different (without pictograms median, 70% vs with pictograms median, 70%). Accompanying pictograms did not significantly improve the assessment of abdominal pain symptoms. Accompanying pictograms were beneficial for concordance rates for nausea and vomiting symptoms (without pictograms median, 67% vs with pictograms median, 100%; P = .047). Subgroup analyses for children aged 8-12 years of age revealed similar results (concordance on the presence of nausea and vomiting without pictograms median, 67% vs with pictograms median, 100%; P = .015). Subgroup analyses for children ages 12-18 years showed no significant differences in concordance rates.

CONCLUSIONS

Pictograms do not seem to improve the assessment of FAPDs. However, the use of pictograms improves the evaluation of nausea and vomiting, especially for children aged 8-12 years. Therefore, HCPs could consider using pictograms in that setting during consultations.

Diagnostic Utility of Mucosal Biopsies Taken During Colonoscopy-Guided Colonic Manometry Catheter Placement

OBJECTIVES

The diagnostic utility of mucosal biopsies taken during colonoscopy-guided colonic manometry catheter placement is unknown. The aims of our study were to determine the frequency and histopathology results of mucosal biopsies during these procedures and to assess whether there were any associations between the histology or gross findings with manometry results.

METHODS

We performed a retrospective chart review of children who had a colonic manometry study completed between 2008 and 2020 at a quaternary children's hospital. We captured patient demographics, biopsy locations, histopathology results, gross endoscopy findings, and manometry results. The chi-squared test and when appropriate Fisher exact test was used to evaluate categorical associations.

RESULTS

One hundred forty-eight patients were included. One hundred eighteen (80%) had colonic biopsy and 63 (43%) had ileal biopsy. Colonic histology findings, which patients could have multiple, included lymphonodular hyperplasia (34%), normal (27%), chronic inflammation (24%), melanosis coli (21%), colonic eosinophilia (10%), and acute inflammation (8%). Ileal histology findings included increased Peyer patches (44%), normal (44%), acute inflammation (11%), chronic inflammation (3%), eosinophilia (5%), and eosinophilic ileitis (3%). The majority of acute and chronic inflammation was graded as mild. There were no statistically significant associations of histology to gross endoscopy or manometry findings.

CONCLUSIONS

Colonic biopsies are obtained in the majority of patients presenting for colonic manometry evaluation with ileal biopsies obtained less frequently. Histopathology findings are noted frequently, but the majority are the result of or did not impact clinical care. There were no associations between abnormal histopathology or abnormal gross endoscopy findings with colonic manometry results.

The prevalence and risk factors of irritable bowel syndrome (PRIBS study) among adults in low- and middle-income countries: A multicenter cross-sectional study

Background and Aims

Because of the plenty and abundance of risk factors and the expected increase in the prevalence of irritable bowel syndrome (IBS) in the world in general and in low- and middle-income countries in particular, this international cross-sectional study was conducted in 15 low- and middle-income countries according to our previous protocol, NCT05340400.

Methods

Participants were recruited in the period from April 22, 2022 to June 14, 2022. The diagnosis of IBS was according to ROME IV. We determined the physical activity, daily stress, and fatigue of the participants. A large number of collaborators were chosen from different regions and institutions within each country to achieve diversity within the sample and reduce the probability of bias.

Results

The prevalence of IBS appears to be higher in low- and middle-income countries (mean = 25.2%, range [6.2%-44.2%]) than in high-income countries, with a higher prevalence among Africans than Caucasians and Asians. The prevalence of IBS increased in the fourth decade by 32.1% and in the fifth decade by 31.1% (p-value < 0.001). In addition to the previously known risk factors for IBS such as female sex, smoking, psychological stress, and chronic fatigue, other risk factors were discovered such as chronic diseases, including high blood pressure and diabetes, allergies to some substances, previous infection with COVID-19, and the participant having a first-degree relative with a patient. There are also some other modifiable risk factors, such as an abnormal body mass index (whether high or low), smoking, a protein- or fat-rich diet, drinking caffeine-containing beverages, and poor physical activity.

Conclusions

Highlighting the prevalence and increasing risk factors of IBS in developing countries should draw the attention of those responsible for health care in these countries and reduce the risk factors.

Pediatric Rome IV diagnosis agreement is greater than agreement on diagnostic testing

BACKGROUND

Pediatric Rome IV criteria are used to diagnose childhood functional gastrointestinal disorders (FGIDs). This study of pediatric gastroenterology physicians measured their agreement in (1) Making a pediatric Rome IV FGID diagnosis; and (2) Diagnostic testing for patients with FGIDs.

METHODS

Pediatric gastroenterologists and pediatric gastroenterology fellows at two medical centers completed a survey containing clinical FGID vignettes. For each vignette, raters identified the most likely Rome IV diagnosis(es) and selected which diagnostic test(s) (if any) they typically would obtain. The survey was re-administered within 3 months. Inter-rater and intra-rater weighted percent agreement was determined. Linear mixed modeling identified sources of variability in diagnostic testing.

KEY RESULTS

Thirty-four raters completed the initial survey of whom thirty-one (91%) completed the repeat survey. Overall inter-rater agreement on Rome IV diagnoses was 68% for initial and repeat surveys whereas intra-rater agreement was 76%. In contrast, overall inter-rater agreement on diagnostic testing was <30% for both initial and repeat surveys and intra-rater agreement was only 57%. Between-physician differences accounted for 43% of the variability in the number of tests selected. Rater identified use of Rome criteria in clinical practice was associated with 1.1 fewer diagnostic tests on average (95% CI 0.2-2.0, p = 0.015). Higher intra-rater agreement was noted for diagnostic testing in faculty when compared to fellows (p = 0.009).

CONCLUSIONS & INFERENCES

In a multicenter evaluation among pediatric gastroenterology physicians, pediatric Rome IV diagnostic agreement was higher than that reported for previous Rome versions, and higher than agreement on diagnostic testing.

LMWP (S3-3) from the Larvae of Musca domestica Alleviate D-IBS by Adjusting the Gut Microbiota

Diarrhea-based Irritable Bowel Syndrome (D-IBS) and diarrhea are both associated with ecological imbalance of the gut microbiota. Low Molecular Weight Peptides (LMWP) from the larvae of Musca domestica have been shown to be effective in the treatment of diarrhea and regulation of gut microbiota. Meanwhile, the single polypeptide S3-3 was successfully isolated and identified from LMWP in our previous studies. It remains unclear exactly whether and how LMWP (S3-3) alleviate D-IBS through regulating gut microbiota. We evaluated the gut microbiota and pharmacology to determine the regulation of gut microbiota structure and the alleviating effect on D-IBS through LMWP (S3-3). The rates of loose stools, abdominal withdrawal reflex (AWR) and intestinal tract motility results revealed that LMWP (S3-3) from the larvae of Musca domestica had a regulating effect against diarrhea, visceral hypersensitivity and gastrointestinal (GI) dysfunction in D-IBS model mice. Additionally, 16S rRNA gene sequencing was utilized to examine the gut microbiota, which suggests that LMWP induce structural changes in the gut microbiota and alter the levels of the following gut microbiota: Bacteroidetes, Proteobacteria and Verrucomicrobia. LMWP putatively functioned through regulating 5-HT, SERT, 5-HT2AR, 5-HT3AR and 5-HT4R according to the results of ELISA, qRT-PCR and IHC. The findings of this study will contribute to further understanding how LMWP (S3-3) attenuate the effects of D-IBS on diarrhea, visceral hypersensitivity and GI dysfunction.

Pediatric Aspects of Nutrition Interventions for Disorders of Gut-Brain Interaction

Dietary factors may play an important role in the generation of symptoms in children with disorders of gut-brain interaction (DGBIs). Although dietary modification may provide successful treatment, there is a relative paucity of controlled trials that have shown the effectiveness of dietary interventions. This study is a narrative review that explores the existing literature on food and pediatric DGBIs. The following have been shown to be beneficial: (i) in infants with colic, removing cow's milk from the infant's diet or from the maternal diet in those who are breastfed; (ii) in infants with regurgitation, adding thickeners to the formula or removing cow's milk protein from the infant's diet or the maternal diet in those who are breastfed; and (iii) in children with pain-predominant DGBIs, using soluble fiber supplementation or a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols diet. In children with functional constipation, there is no evidence that adding fiber is beneficial. Given that most dietary interventions include restriction of different foods in children, a thoughtful approach and close follow-up are needed.

Effects of probiotic supplementation on abdominal pain severity in pediatric patients with irritable bowel syndrome: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Probiotic supplementation has been used to alleviate abdominal pain in children and adolescents with irritable bowel syndrome (IBS), but the evidence is not compelling. Thus, a systematic review and meta-analysis of randomized clinical trials (RCTs) were performed to investigate the effects of probiotic supplementation on abdominal pain in pediatric patients with IBS.

METHODS

PubMed/MEDLINE, Web of Science, Scopus, Cochrane Library, and Embase were the available databases searched to find relevant randomized clinical trials up to April 2021. The effect size was expressed as weighted mean difference (WMD) and 95% confidence interval (CI).

RESULTS

Seven RCTs with 441 participants were included, from which the meta-analysis demonstrated that probiotic supplementation has a significant effect on reducing abdominal pain in pediatric patients with IBS (WMD = - 2.36; 95% CI - 4.12 to - 0.60; P = 0.009). Although our study involved children and adolescents (≤ 18 years), the effects of probiotic supplementation seem to be more potent in patients under 10 years old (WMD = - 2.55; 95% CI - 2.84 to - 2.27) compared to patients aged 10-18 years (WMD = - 1.70; 95% CI - 2.18 to - 1.22). The length of supplementation longer than four weeks was more effective (WMD = - 2.43; 95% CI - 2.76 to - 2.09).

CONCLUSION

Probiotic supplementation can reduce abdominal pain in pediatric patients with IBS.

Dietary interventions for functional abdominal pain disorders in children: a systematic review and meta-analysis

BACKGROUND

Functional abdominal pain disorders (FAPDs) are common among children and are associated with decreased quality of life and school attendance. Several dietary interventions have been suggested to improve symptoms of FAPDs. This systematic review assessed the efficacy and safety of dietary interventions for pediatric FAPDs.

DESIGN AND METHODS

Electronic databases were searched (inception-October 2021). Systematic reviews or RCTs were included if children (4-18 years) with FAPDs were treated with dietary interventions and compared to placebo, no diet or any other diet. Data extraction and assessment of quality of evidence based on GRADE system was independently performed by two review authors. Outcomes were treatment success, pain intensity and frequency, and withdrawal due to adverse events.

RESULTS

Twelve articles were included, representing data of 819 pediatric FAPD patients. Trials investigating fibers, FODMAP diet, fructans, fructose-restricted diet, prebiotic (inulin), serum-derived bovine immunoglobulin, and vitamin D supplementation were included. We found very low-certainty evidence that the use of fibers leads to higher treatment success (NNT = 5).

CONCLUSION

Based on current evidence, the use of fibers can be discussed in daily practice. High-quality intervention trials are highly needed to investigate if other dietary interventions are effective in the treatment of pediatric FAPD.

Fructan-sensitive children with irritable bowel syndrome have distinct gut microbiome signatures

BACKGROUND

Dietary fructans may worsen gastrointestinal symptoms in children with irritable bowel syndrome (IBS).

AIM

To determine whether gut microbiome composition and function are associated with childhood IBS fructan-induced symptoms.

METHODS

Faecal samples were collected from 38 children aged 7-17 years with paediatric Rome III IBS, who previously completied a double-blind, randomised, placebo-controlled crossover (fructan vs maltodextrin) trial. Fructan sensitivity was defined as an increase of ≥30% in abdominal pain frequency during the fructan diet. Gut microbial composition was determined via 16Sv4 rDNA sequencing. LEfSe evaluated taxonomic composition differences. Tax4Fun2 predicted microbial fructan metabolic pathways.

RESULTS

At baseline, 17 fructan-sensitive (vs 21 fructan-tolerant) subjects had lower alpha diversity (q < 0.05) and were enriched in the genus Holdermania. In contrast, fructan-tolerant subjects were enriched in 14 genera from the class Clostridia. During the fructan diet, fructan-sensitive (vs tolerant) subjects were enriched in both Agathobacter (P = 0.02) and Cyanobacteria (P = 0.0001). In contrast, fructan-tolerant subjects were enriched in three genera from the Clostridia class. Comparing the fructan vs maltodextrin diet, fructan-sensitive subjects had a significantly increased relative abundance of Bifidobacterium (P = 0.02) while fructan-tolerant subjects had increased Anaerostipes (P = 0.03) during the fructan diet. Only fructan-sensitive subjects had a trend towards increased predicted β-fructofuranosidase during the fructan vs maltodextrin diet.

CONCLUSIONS

Fructan-sensitive children with IBS have distinct gut microbiome signatures. These microbiome signatures differ both at baseline and in response to a fructan challenge.

The relationship between mucosal inflammatory cells, specific symptoms, and psychological functioning in youth with irritable bowel syndrome

Both mucosal inflammation and psychologic dysfunction have been implicated in irritable bowel syndrome (IBS). While some relationships between inflammation (mast cells and eosinophils) and depression have been reported in adults with IBS, relationships between inflammation and psychologic function have not been studied in children and adolescents. The aims of the current study were to: (1) assess densities of colonic mast cells, eosinophils, and TH17 cells in youth with IBS; and, (2) explore relationships between these cells and specific IBS symptoms and psychologic functioning. Utilizing previously obtained biopsies from the descending and rectosigmoid colons, densities were determined for mast cells, eosinophils, and TH17 cells, respectively, in 37 youth with IBS and 10 controls. In IBS patients, densities were assessed in relation to specific IBS symptoms and in relation to self-report anxiety and depression scores. In both the descending and rectosigmoid colons, densities of mast cells, eosinophils, and TH17 cells were higher in IBS patients as compared to controls. In IBS patients, rectosigmoid mast cell density was higher in those reporting pain relief with defecation. Also, in IBS patients, rectosigmoid eosinophilia was associated with higher anxiety scores and eosinophil density correlated with depression scores. In the descending colon, eosinophil and mast cell densities both correlated with depression scores. In conclusion, mucosal inflammation (mast cells and eosinophils) is associated with pain relief with defecation and with anxiety and depression in youth with IBS.

Hypomorphic SI genetic variants are associated with childhood chronic loose stools

OBJECTIVE

The SI gene encodes the sucrase-isomaltase enzyme, a disaccharidase expressed in the intestinal brush border. Hypomorphic SI variants cause recessive congenital sucrase-isomaltase deficiency (CSID) and related gastrointestinal (GI) symptoms. Among children presenting with chronic, idiopathic loose stools, we assessed the prevalence of CSID-associated SI variants relative to the general population and the relative GI symptom burden associated with SI genotype within the study population.

METHODS

A prospective study conducted at 18 centers enrolled 308 non-Hispanic white children ≤18 years old who were experiencing chronic, idiopathic, loose stools at least once per week for >4 weeks. Data on demographics, GI symptoms, and genotyping for 37 SI hypomorphic variants were collected. Race/ethnicity-matched SI data from the Exome Aggregation Consortium (ExAC) database was used as the general population reference.

RESULTS

Compared with the general population, the cumulative prevalence of hypomorphic SI variants was significantly higher in the study population (4.5% vs. 1.3%, P < .01; OR = 3.5 [95% CI: 6.1, 2.0]). Within the study population, children with a hypomorphic SI variant had a more severe GI symptom burden than those without, including: more frequent episodes of loose stools (P < .01), higher overall stool frequency (P < .01), looser stool form (P = .01) and increased flatulence (P = .02).

CONCLUSION

Non-Hispanic white children with chronic idiopathic loose stools have a higher prevalence of CSID-associated hypomorphic SI variants than the general population. The GI symptom burden was greater among the study subjects with a hypomorphic SI variant than those without hypomorphic SI variants.

Literature Review: Dietary Intervention Adherence and Adherence Barriers in Functional Gastrointestinal Disorder Studies

Dietary management is key in controlling functional gastrointestinal disorders (FGIDs) symptoms. However, the degree to which patients with FGIDs in clinical studies adhere to dietary recommendations is unknown. Our aim was to evaluate adherence, dietary education, and adherence-related factors in FGIDs dietary intervention trials. A literature search was performed using MEDLINE, Google Scholar, and SCOPUS for clinical trials evaluating dietary management of FGIDs. Full manuscripts published from January 2000 through August 2018 were reviewed. Data including definitions of adherence and rates, study design, dietary education, use of a dietitian, provision of study foods, potential adherence barriers, and dropouts were captured. A total of 21 publications were included. Fifteen (67%) focused on the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, 5 (24%) on fiber supplementation, and 1 (9%) on a low carbohydrate diet. Fifteen (71%) were randomized controlled trials. Meals/supplements were provided to the study participants in 27%, 80%, and 100%, of the low FODMAP, fiber, and low carbohydrate studies, respectively, which appeared to significantly enhance adherence (P<0.03). Eighteen studies (81%) provided either written or oral diet information to study participants. Overall, only 10 publications (48%) provided adherence data. Nine (60%) of the low FODMAP studies provided adherence data (range, 30% to 100%); ranges could not be calculated for the other dietary trials. The most common method to measure adherence was via food diaries. Therefore, adherence is not often measured in FGIDs dietary intervention clinical trials; when reported, rates of adherence range widely. Studies providing food had the highest adherence rates.

The gut microbiome as a predictor of low fermentable oligosaccharides disaccharides monosaccharides and polyols diet efficacy in functional bowel disorders

PURPOSE OF REVIEW

Fermentable oligosaccharides disaccharides monosaccharides and polyols (FODMAP) dietary restriction ameliorates irritable bowel syndrome (IBS) symptoms; however, not all individuals with IBS respond. Given the gut microbiome's role in carbohydrate fermentation, investigators have evaluated whether the gut microbiome may predict low FODMAP diet efficacy.

RECENT FINDINGS

Gut microbiome fermentation, even to the same carbohydrate, is not uniform across all individuals with several factors (e.g. composition) playing a role. In both children and adults with IBS, studies are emerging suggesting the gut microbiome may predict low FODMAP diet efficacy. However, there is significant heterogeneity in the approaches (study population, microbiome assessment methods, statistical techniques, etc.) used amongst these studies.

SUMMARY

The gut microbiome holds promise as a predictor of low FODMAP diet efficacy. However, further investigation using standardized approaches to evaluate the microbiome while concomitantly assessing other potential predictors are needed to more rigorously evaluate this area.

Abdominal Pain in Children Develops With Age and Increases With Psychosocial Factors

BACKGROUND & AIMS

Functional gastrointestinal disorders are highly prevalent, cause significant suffering, and are costly to society. Pain is a central feature of 2 of the most common functional gastrointestinal disorders: irritable bowel syndrome and functional dyspepsia. Although these disorders have been well studied in adults, their etiology is poorly understood. We sought to identify early life factors associated with the development of abdominal pain in children (age, 2-12 y).

METHODS

We collected data from the All Babies in Southeast Sweden study of 1781 children, born from October 1, 1997, through October 31, 1999, whose families answered questions about abdominal pain and risk factors at birth, 1 year, 2.5 years, 5 years, 8 years, and 10 to 12 years. We used latent growth curve models to evaluate risk factors for development of abdominal pain. The primary outcomes were prevalence of abdominal pain and associated factors.

RESULTS

The prevalence of abdominal pain increased linearly with age in the study cohort, increasing by approximately 6% per year. Psychosocial variables associated with slope of the growth curve included lower emotional control at age 2 years (P = .005), parental concern for the child at age 2 years (P = .02), and measures of parental stress (P = .004). Nonvaginal birth was associated with a reduced slope of the growth curve (P = .03).

CONCLUSIONS

In a study of children in Sweden, we found early psychosocial environment and mode of delivery at birth was associated with development of childhood abdominal pain. Factors associated with development of the early immune system, identified in previous recall-based research, were not supported by data from this study. These findings have important implications for the prevention of abdominal pain in children and later in life.

Irritable Bowel Syndrome between Molecular Approach and Clinical Expertise-Searching for Gap Fillers in the Oxidative Stress Way of Thinking

Irritable bowel syndrome (IBS) remains to date an intriguing functional gastrointestinal disorder. Recent studies described a multitude of exogenous factors that work together in IBS, gradually impairing intestinal lining cellular metabolism, including oxidative status balance, with or without a genetic background. Although the current biomarkers support the differentiation between IBS subtypes and other functional gastrointestinal disorder, they are mostly non-specific, referring to clinical, biochemical, and inflammatory imbalances. Since IBS could be also the result of deficient signaling pathways involving both gastrointestinal secretion and neuro-vegetative stimulation, IBS makes no exception from the oxidative hypothesis in the pathological mechanisms. Regarding the oxidative stress implication in IBS, the previous research efforts showed controversial results, with some animal models and patient studies reporting clear oxidative imbalance both on systemic and local levels, but still with no concrete evidence to point to a direct correlation between oxidative stress and IBS. Additionally, it seems that a major role could be also attributed to gut microbiota and their ability to shape our bodies and behaviors. Moreover, the genetic features study in IBS patients showed that several genetic similarities point to a possible correlation of IBS with affective spectrum disorders. Thus, we focus here the discussion on the assumption that IBS could in fact be more likely a stress-related disorder rather than a gastrointestinal one.

'Rapid transit' constipation in children: a possible genesis for irritable bowel syndrome

Children with chronic idiopathic constipation (CIC) often end up at the surgeon when medical treatments have failed. This opinion piece discusses a recently described pattern of CIC called 'Rapid transit constipation (RTC)' first identified in 2011 as part of surgical workup. RTC was identified using a nuclear medicine gastrointestinal transit study (NMGIT or nuclear transit study) to determine the site of slowing within the bowel and to inform surgical treatment. Unexpectedly, we found that RTC occured in 29% of 1000 transit studies in a retrospective audit. Irritable bowel syndrome (IBS) occurs in 7-21% of the population, with a higher prevalence in young children and with constipation type dominating in the young. While 60% improve with time, 40% continue with symptoms. First-line therapy for IBS in adults is a diet low in fermentable oligosaccharides, disaccharides, monosaccharides and polyols which reduces symptoms in > 70% of patients. In children with functional gastrointestinal disorders, fructose intolerance occurs in 35-55%. Reducing fructose produced significant improvement in 77-82% of intolerant patients. In children with RTC and a positive breath test upon fructose challenge, we found that exclusion of fructose significantly improved constipation, abdominal pain, stool consistency and decreased laxative use. We hypothesise that positive breath tests and improvement of pain and bowel frequency with sugar exclusion diets in RTC suggest these children have IBS-C. These observations raise the possibility that many children with CIC could be treated by reducing fructose early in their diet and this might prevent the development of IBS in later life.

Leveraging Human Microbiome Features to Diagnose and Stratify Children with Irritable Bowel Syndrome

Accurate diagnosis and stratification of children with irritable bowel syndrome (IBS) remain challenging. Given the central role of recurrent abdominal pain in IBS, we evaluated the relationships of pediatric IBS and abdominal pain with intestinal microbes and fecal metabolites using a comprehensive clinical characterization and multiomics strategy. Using rigorous clinical phenotyping, we identified preadolescent children (aged 7 to 12 years) with Rome III IBS (n = 23) and healthy controls (n = 22) and characterized their fecal microbial communities using whole-genome shotgun metagenomics and global unbiased fecal metabolomic profiling. Correlation-based approaches and machine learning algorithms identified associations between microbes, metabolites, and abdominal pain. IBS cases differed from controls with respect to key bacterial taxa (eg, Flavonifractor plautii and Lachnospiraceae bacterium 7_1_58FAA), metagenomic functions (eg, carbohydrate metabolism and amino acid metabolism), and higher-order metabolites (eg, secondary bile acids, sterols, and steroid-like compounds). Significant associations between abdominal pain frequency and severity and intestinal microbial features were identified. A random forest classifier built on metagenomic and metabolic markers successfully distinguished IBS cases from controls (area under the curve, 0.93). Leveraging multiple lines of evidence, intestinal microbes, genes/pathways, and metabolites were associated with IBS, and these features were capable of distinguishing children with IBS from healthy children. These multi-omics features, and their links to childhood IBS coupled with nutritional interventions, may lead to new microbiome-guided diagnostic and therapeutic strategies.

Elimination of Fermentable Carbohydrates to Reduce Gastrointestinal Symptoms in Pediatric Patients With Irritable Bowel Syndrome: A Narrative Review

Irritable bowel syndrome (IBS) is classified as a functional gastrointestinal (GI) disorder characterized by abdominal pain, bloating, and changes in bowel function. Although the pathophysiology of IBS is incompletely understood, fermentable carbohydrates are implicated as a potential cause of symptoms. An elimination diet, such as a low-FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet, represents a potential intervention for reducing GI symptoms in patients with IBS. The role of fermentable carbohydrates in symptom onset is well studied in adult patients with IBS; however, less research exists in the pediatric population. This review sought to explore evidence for the role of dietary fermentable carbohydrate elimination to reduce GI symptoms (abdominal pain, stool changes, abdominal bloating) in children and adolescents (4-19 years of age) diagnosed with IBS based on Rome III or IV criteria. Five studies of neutral to positive quality rating were identified and analyzed using the Academy of Nutrition and Dietetics Evidence Analysis Process. These studies demonstrate that dietary elimination of fermentable carbohydrates, such as through a low-FODMAP diet, reduces the severity of 1 or more GI symptoms in about one-quarter to one-half of pediatric patients with IBS. Patients without improvement are considered "nonresponders" and may require an alternative intervention. More research is needed to establish the best way to identify patients who would respond to elimination diets vs other IBS treatment strategies.

Update on Dietary Management of Childhood Functional Abdominal Pain Disorders

Diet plays a significant role for children with functional abdominal pain disorders. A large majority of these children identify at least 1 food that exacerbates their symptoms. Malabsorbed carbohydrates may have both direct and microbiome-mediated physiologic effects. There are several factors associated with carbohydrate symptom generation, including (1) the amount ingested, (2) ingestion with a meal, (3) small intestinal enzymatic activity, (4) consuming the carbohydrate with microorganisms capable of breaking down the carbohydrate, (5) the gut microbiome, and (6) host factors. Therapies include carbohydrate (single and/or comprehensive) restriction, selective prebiotic and/or enzyme supplementation. Fiber supplementation may also be beneficial.

Tong-Xie-Yao-Fang Regulates 5-HT Level in Diarrhea Predominant Irritable Bowel Syndrome Through Gut Microbiota Modulation

Tong-Xie-Yao-Fang (TXYF) has been widely used for the treatment of diarrhea-predominant irritable bowel syndrome (IBS-D) in traditional Chinese medicine. However, its mechanism of action in the treatment of IBS-D remains to be fully understood. Recent reports have shown that Clostridium species in the gut can induce 5-HT production in the colon, which then contributes to IBS-D. Due to the wide use of TXYF in the clinical treatment of IBS-D and the close relationship between gut microbiota and IBS-D, we hypothesize that TXYF treats IBS-D by modulating gut microbiota and regulating colonic 5-HT levels. In this study, variation analysis of 16S rRNA was conducted to evaluate changes in the distribution of gut microbiota in IBS-D model rats after TXYF treatment. Moreover, we investigated whether TXYF could affect colonic 5-HT levels in IBS-D model rats. We then performed fecal transplantation experiments to confirm the effects of TXYF on gut microbiota and 5-HT levels. We found that TXYF treatment can ameliorate IBS-D and regulate 5-HT levels in colon tissue homogenates. TXYF treatment also affected the diversity of gut microbiota and altered the relative abundance of Akkermansia and Clostridium sensu stricto 1 in gut flora populations. Finally, we showed that fecal transplantation from TXYF-treated rats could relieve IBS-D and regulate 5-HT levels in colon tissue homogenates. In conclusion, the present study demonstrates that TXYF treatment diminishes colonic 5-HT levels and alleviates the symptoms of IBS-D by favorably affecting microbiota levels in gut flora communities.

Evaluation of FODMAP Carbohydrates Content in Selected Foods in the United States

We analyzed the fermentable oligosaccharide, disaccharide, monosaccharide, and polyols (FODMAP) content of several foods potentially low in FODMAP which are commonly consumed by children. We determined that several processed foods (eg, gluten-free baked products) had unlabeled FODMAP content. Determining FODMAP content within foods distributed in the US may support educational and dietary interventions.

[Implementation of a low FODMAP diet for functional abdominal pain]

INTRODUCTION

The low FODMAP diet (fermentable oligosaccharides, monosaccharides, disaccharides, and polyols) has shown to be effective in adult patients with irritable bowel syndrome, but there are few studies on paediatric patients. The aim of this study is to assess the implementation and the outcomes of a low FODMAP diet in the treatment of functional abdominal pain in children from a Mediterranean area.

MATERIAL AND METHODS

A table was designed in which foods were classified according to their FODMAP content, as well as a 'Symptoms and Stools Diary'. A prospective study was conducted on children with functional abdominal pain in our Paediatric Gastroenterology Unit.

RESULTS

A total of 22 patients were enrolled in the trial, and 20 completed it. Data were collected of the abdominal pain features over a period of 3 days, and then patients followed a two-week low FODMAP diet. Afterwards, information about abdominal pain features was collected again. After the diet, they showed fewer daily abdominal pain episodes compared to baseline (1.16 [IQR: 0.41-3.33] versus 2 [IQR: 1.33-6.33] daily episodes, P=.024), less pain severity compared to baseline (1.41cm [IQR: 0.32-5.23] versus 4.63cm [IQR: 2.51-6.39] measured by 10-cm Visual Analogue Scale, P=.035), less interference with daily activities, and less gastrointestinal symptoms. Only 15% of patients found it difficult to follow the diet.

CONCLUSIONS

The implementation of a low FODMAP diet for 2 weeks in a Mediterranean paediatric population diagnosed with functional abdominal pain is possible with adapted diets. It was highly valued by patients, and they showed an improvement in abdominal pain symptoms assessed by objective methods.

Allergic Proctocolitis Is a Risk Factor for Functional Gastrointestinal Disorders in Children

OBJECTIVE

To test the hypothesis that allergic proctocolitis, a cause of self-limiting rectal bleeding in infants, can predispose to the development of functional gastrointestinal disorders (FGIDs) later in childhood.

STUDY DESIGN

We studied a cohort of 80 consecutive patients diagnosed with allergic proctocolitis. Their sibling or matched children presenting to the same hospital for minor trauma served as controls. Parents of the patients with allergic proctocolitis and controls participated in a telephone interview every 12 months until the child was at least 4 years old. At that time, they were asked to complete the parental Questionnaire on Pediatric Gastrointestinal Symptoms, Rome III version.

RESULTS

Sixteen of the 160 subjects (10.0%) included in the study met the Rome III criteria for FGIDs. Among the 80 patients with allergic proctocolitis, 12 (15.0%) reported FGIDs, compared with 4 of 80 (5.0%) controls (P = .035). After adjustment for age and sex, the OR for FGIDs in allergic proctocolitis group was 4.39 (95% CI, 1.03-18.68). FGIDs were significantly associated with iron deficiency anemia, duration of hematochezia, and younger age at presentation. In a multivariate analysis, only the duration of hematochezia was significantly associated with the development of FGIDs (OR, 3.14; 95% CI,1.72-5.74).

CONCLUSIONS

We have identified allergic proctocolitis as a new risk factor for the development of FGIDs in children. Our data suggest that not only infection, but also a transient early-life allergic inflammatory trigger may induce persistent digestive symptoms, supporting the existence of "postinflammatory" FGIDs.

The Role of Bacteria, Probiotics and Diet in Irritable Bowel Syndrome

Irritable bowel syndrome is a highly prevalent gastrointestinal disorder that threatens the quality of life of millions and poses a substantial financial burden on healthcare systems around the world. Intense research into the human microbiome has led to fascinating discoveries which directly and indirectly implicate the diversity and function of this occult organ in irritable bowel syndrome (IBS) pathophysiology. The benefit of manipulating the gastrointestinal microbiota with diet and probiotics to improve symptoms has been demonstrated in a wealth of both animal and human studies. The positive and negative mechanistic roles bacteria play in IBS will be explored and practical probiotic and dietary choices offered.

Irritable bowel syndrome - from etiopathogenesis to therapy

Irritable bowel syndrome (IBS) is a chronic and relapsing functional gastrointestinal disorder that affects 9-23% of the population across the world. Patients with IBS are often referred to gastroenterology, undergo various investigations, take various medicines, take time off work and have a poor quality of life. The pathophysiology of IBS is not yet completely understood and seems to be multifactorial. Many pathogenetic factors, in various combinations, and not all necessarily present in each patient, can play an important role. Discomfort or abdominal pain relieived by defacation, asociated with a change in stool form, is a typical clinical manifestation of IBS. Many factors, such as emotional stress and eating, may exacerbate the symptoms. A timely diagnosis of IBS is important so that treatment which will provide adequate symptomatic relief (diarrhoea, constipation, pain and boaring) can be introduced. The diagnosis of IBS is not confirmed by a specific test or structural abnormality. It is made using criteria based on clinical symptoms such as Rome criteria, unless the symptoms are thought to be atypical. Today the Rome Criteria IV is the current gold-standard for the diagnoses of IBS. Treatment of patients with IBS requires a multidisciplinary approach. Some patients respond well to non-pharmacological treatment, while others also require pharmacological treatment. This review will provide a summary of pathophysiology, diagnostic criteria and therapies for IBS.

Treatment of Chronic Atopy and Irritable Bowel Syndrome in a 7-year-old: A Case Report

Irritable bowel syndrome and atopic conditions can co-occur in children and appear to be associated with alterations in the gut microbiota and immune function. A 7-y-old girl was frequently sent home from school due to symptoms related to her long-standing urticaria and gastrointestinal complaints. She was evaluated by pediatric gastroenterologists and allergists; however, she did not respond to treatment. The successful approach to this patient's treatment included dietary modifications and probiotics guided by clinical insight gleaned from often-overlooked diagnostic biomarkers.

Luminal contents from the gut of colicky infants induce visceral hypersensitivity in mice

BACKGROUND

The pathophysiology of infantile colic is poorly understood, though various studies report gut microbiota dysbiosis in colicky infants. We aimed to test the hypothesis that colic-related dysbiosis is associated with visceral hypersensitivity triggered by an altered luminal milieu.

METHODS

Fecal samples from seven colicky and seven non-colicky infants were studied. Fecal supernatants (FS) were infused into the colons of C57/Bl6 mice (n=10/specimen). Visceral sensitivity was subsequently assessed in the animals by recording their abdominal muscle response to colorectal distension (CRD) by electromyography (EMG). Serine and cysteine protease activities were assessed in FS with specific substrates. Infant fecal microbiota composition was analyzed by DNA extraction and 16S rRNA gene pyrosequencing.

KEY RESULTS

FS from colicky infants triggered higher EMG activity than FS from non-colicky infants in response to both the largest CRD volumes and overall, as assessed by the area under the curve of the EMG across all CRD volumes. Infant crying time strongly correlated with mouse EMG activity. Microbiota richness and phylogenetic diversity were increased in the colicky group, without showing prominent microbial composition alterations. Only Bacteroides vulgatus and Bilophila wadsworthia were increased in the colicky group. Bacteroides vulgatus abundance positively correlated with visceral sensitivity. No differences were found in protease activities.

CONCLUSIONS & INFERENCES

Luminal contents from colicky infants trigger visceral hypersensitivity, which may explain the excessive crying behavior of these infants. Additional studies are required to determine the nature of the compounds involved, their mechanism of action, and the potential implications of intestinal microbiota in their generation.

Chronic Early-life Stress in Rat Pups Alters Basal Corticosterone, Intestinal Permeability, and Fecal Microbiota at Weaning: Influence of Sex

Background/Aims

Wistar rat dams exposed to limited nesting stress (LNS) from post-natal days (PND) 2 to 10 display erratic maternal behavior, and their pups show delayed maturation of the hypothalamic-pituitary-adrenal axis and impaired epithelial barrier at PND10 and a visceral hypersensitivity at adulthood. Little is known about the impact of early life stress on the offspring before adulthood and the influence of sex. We investigated whether male and female rats previously exposed to LNS displays at weaning altered corticosterone, intestinal permeability, and microbiota.

Methods

Wistar rat dams and litters were maintained from PND2 to 10 with limited nesting/bedding materials and thereafter reverted to normal housing up to weaning (PND21). Control litters had normal housing. At weaning, we monitored body weight, corticosterone plasma levels (enzyme immunoassay), in vivo intestinal to colon permeability (fluorescein isothiocyanate-dextran 4 kDa) and fecal microbiota (DNA extraction and amplification of the V4 region of the 16S ribosomal RNA gene).

Results

At weaning, LNS pups had hypercorticosteronemia and enhanced intestinal permeability with females > males while body weights were similar. LNS decreased fecal microbial diversity and induced a distinct composition characterized by increased abundance of Gram positive cocci and reduction of fiber-degrading, butyrate-producing, and mucus-resident microbes.

Conclusions

These data indicate that chronic exposure to LNS during the first week post-natally has sustained effects monitored at weaning including hypercorticosteronemia, a leaky gut, and dysbiosis. These alterations may impact on the susceptibility to develop visceral hypersensitivity in adult rats and have relevance to the development of irritable bowel syndrome in childhood.

Activation of 5-HT and NR2B contributes to visceral hypersensitivity in irritable bowel syndrome in rats

The roles of 5-hydroxytryptamine (5-HT) and spinal N-methyl-D-aspartic acid receptor 2B (NR2B) in visceral hypersensitivity were investigated. A rat model with irritable bowel syndrome (IBS) was established by intracolonic injections of acetic acid onpost-natal days 8-21. Rats were randomly divided into five groups: normal intact (control) group, IBS model group, Ro25-6981-treated IBS rats (Ro25-6981, a NR2B antagonist) group, amitriptyline-treated IBS rats (amitriptyline, a 5-HT antagonist) and Ro25-6981 plus amitriptyline-treated IBS rats (Ro25-6981+amitriptyline) group. The expressions of 5-HT, NR2B, 5-HT2AR, 5-HT7R, SERT, TNF-α and IL-1β in colon, dorsal root ganglion (DRG) and hypothalamus, respectively, were measured by Immunohistochemical staining, Real-Time Reverse Transcription-PCR and Western blotting. Our results showed increased DRG and hypothalamus expression of 5-HT, NR2B, 5-HT2AR, 5-HT7R in IBS model group and decreased expression of those in Ro25-6981 and amitriptyline alone or both treatment groups. Moreover, SERT expression was decreased in colorectal, DRG and hypothalamus of ISB model rats, but increased by Ro25-6981 and amitriptyline alone or both treatments. Ro25-6981 and amitriptyline treatment also decreased colorectal expression of TNF-α and IL-1β induced by IBS model. In conclusion, activation of 5-HT and NR2B may play a crucial role in visceral hypersensitivity in irritable bowel syndrome in rats.

Age and cellular context influence rectal prolapse formation in mice with caecal wall colorectal cancer xenografts

In patients with rectal prolapse is the prevalence of colorectal cancer increased, suggesting that a colorectal tumor may induce rectal prolapse. Establishment of tumor xenografts in immunodeficient mice after orthotopic inoculations of human colorectal cancer cells into the caecal wall is a widely used approach for the study of human colorectal cancer progression and preclinical evaluation of therapeutics. Remarkably, 70% of young mice carrying a COLO320DM caecal tumor showed symptoms of intussusception of the large bowel associated with intestinal lumen obstruction and rectal prolapse. The quantity of the COLO320DM bioluminescent signal of the first three weeks post-inoculation predicts prolapse in young mice. Rectal prolapse was not observed in adult mice carrying a COLO320DM caecal tumor or young mice carrying a HT29 caecal tumor. In contrast to HT29 tumors, which showed local invasion and metastasis, COLO320DM tumors demonstrated a non-invasive tumor with pushing borders without presence of metastasis. In conclusion, rectal prolapse can be linked to a non-invasive, space-occupying COLO320DM tumor in the gastrointestinal tract of young immunodeficient mice. These data reveal a model that can clarify the association of patients showing rectal prolapse with colorectal cancer.