Is irritable bowel syndrome a low-grade inflammatory bowel disease?

Serum Leucine-Rich α2 Glycoprotein Could Be a Useful Biomarker to Differentiate Patients with Normal Colonic Mucosa from Those with Inflammatory Bowel Disease or Other Forms of Colitis

(1) Background: Serum leucine-rich α2 glycoprotein (LRG) has been reported as a useful biomarker for monitoring disease activity in patients with inflammatory bowel disease (IBD). We investigated whether serum LRG can differentiate patients with normal colonic mucosa from those with IBD or other forms of colitis. (2) Methods: Patients with diarrhea, abdominal pain, or bloody stools were consecutively enrolled at their initial visit to our hospital. Serum LRG and C-reactive protein were measured, and a colonoscopy and histology were performed. (3) Results: We enrolled 317 patients (181 men, 136 women; median age: 51 years). Based on the endoscopic and histological criteria, 260 patients were diagnosed with ulcerative colitis (n = 134), Crohn's disease (n = 10), infectious colitis (n = 43), diverticular colitis (n = 17), or nonspecific colitis (n = 56). The remaining 57 patients were diagnosed with normal colonic mucosa including histology. The latter group's median LRG value (9.5 µg/mL, range: 5.8-13.5) was significantly lower than that of the other 260 patients (13.6 µg/mL, range: 6.8-62.7, p < 0.0001). The optimal LRG cut-off value of <10.4 µg/mL was derived from the receiver operating characteristic (ROC) curve, showing a 91% sensitivity and 77% specificity for identifying patients with normal colonic mucosa. (4) Conclusions: serum LRG values < 10.4 µg/mL could be a useful biomarker for predicting patients with normal colonic mucosa.

Effect of pine bark extract and its phenolic compounds on selected pathogenic and probiotic bacterial strains

Introduction

Inflammatory bowel disease (IBD) comprises a heterogeneous group of chronic diseases as ulcerative colitis (UC) and Crohn's disease (CD). IBD is the result of a dysregulation of intestinal homeostasis with a host's loss of tolerance toward normal enteric microflora. Plant-based extracts as phenolic compounds can play a role by modulating the intestinal inflammation response.

Methods

The in vitro antimicrobial activity of French maritime pine bark extract (PBE) and its phenolic constituents has been investigated in this study. Furthermore, the ability of PBE and phenolic compounds (caffeic acid, chlorogenic acid, ferulic acid, gallic acid and taxifolin) to modulate the microbiota has been assessed.

Results

Phenolic compounds and PBE showed a great inhibitory effect on the pathogens growth at the highest concentration assessed (1.25 mg/mL). The growth of E. sakazakii and E. faecalis were affected by the effect of caffeic acid and ferulic acid. Taxifolin showed a very strong activity against Listeria sp. (with a reduction ~98%). Gallic acid revealed antibacterial effect on S. aureus at different concentrations. The inhibitory effect of PBE was highly significant on the growth of E. coli O157:H7. PBE, caffeic acid and chlorogenic acid seem to provide the greatest beneficial effect on the probiotic bacteria. However, the highest concentrations of taxifolin may have impaired the growth of beneficial microbiota.

Conclusion

Present findings could be of interest for considering PBE and/or its phenolic constituents as protectors against gastrointestinal disturbances which lead to ulcerative colitis and Crohn's disease.

Cannabidiol and Intestinal Motility: a Systematic Review

Cannabidiol (CBD) is a non-intoxicating cannabinoid extracted from the cannabis plant that is used for medicinal purposes. Ingestion of CBD is claimed to address several pathologies, including gastrointestinal disorders, although limited evidence has been generated thus far to substantiate many of its health claims. Nevertheless, CBD usage as an over-the-counter treatment for gastrointestinal disorders is likely to expand in response to increasing commercial availability, permissive legal status, and acceptance by consumers. This systematic review critically evaluates the knowledge boundaries of the published research on CBD, intestinal motility, and intestinal motility disorders. Research on CBD and intestinal motility is currently limited but does support the safety and efficacy of CBD for several therapeutic applications, including seizure disorders, inflammatory responses, and upper gastrointestinal dysfunction (i.e., nausea and vomiting). CBD, therefore, may have therapeutic potential for addressing functional gastrointestinal disorders. The results of this review show promising in vitro and preclinical data supporting a role of CBD in intestinal motility. This includes improved gastrointestinal-related outcomes in murine models of colitis. These studies, however, vary by dose, delivery method, and CBD-extract composition. Clinical trials have yet to find a conclusive benefit of CBD on intestinal motility disorders, but these trials have been limited in scope. In addition, critical factors such as CBD dosing parameters have not yet been established. Further research will establish the efficacy of CBD in applications to address intestinal motility.

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.

Relationships between body mass index and constipation, gastroesophageal reflux disease, stool forms based on the Bristol Stool Form Scale, and education level: results from an internet survey in Japan

Detailed evaluations of body mass index (BMI) and stool form based on the Bristol Stool Form Scale (BSFS) in individuals with constipation, gastroesophageal reflux disease (GERD), and concomitant constipation and GERD have not been performed in Japan. This study was an internet survey conducted to examine the relationships between BMI and constipation, GERD, stool forms based on the BSFS, and education level. This internet-based survey recruited participants from general public survey panels. 10,000 individuals meeting the eligibility criteria were enrolled. Questions included demographics, medical data, and assessments based on validated measures for constipation and GERD. BMI was significantly lower in males with versus without constipation. BMI was significantly higher with GERD both males and females. Mean BMI increased from the BSFS-1/2 group through the BSFS-3/4/5 to the BSFS-6/7 groups in both sexes. BMI was highest in individuals with a maximum education level of junior high school and second highest in individuals completing high school. This is the first real-world survey that closely examines the relationship between BMI and stool forms of individuals in Japan. When the BMI increased, stool forms varied from hard to watery in Japanese people. BMI was related with education level in Japan. (Trial registration: UMIN000039688).

Factors influencing rectal hypersensitivity in irritable bowel syndrome: A systematic review and meta-analysis

BACKGROUND

A frequent, although not universal, feature of irritable bowel syndrome (IBS) is heightened sensitivity to mechanical stimulation of the rectum, termed rectal hypersensitivity (RH). Differences in RH-based on sex, IBS subtype, IBS diagnostic criteria and age of population studied are incompletely understood. We aimed to determine whether IBS population had lower pain thresholds than healthy controls.

METHODS

We searched MEDLINE and EMBASE databases (1970-2021). Prospective studies that compared pain/discomfort thresholds to mechanical rectal stimuli in IBS and healthy controls were included. Data were pooled for meta-analyses and effect sizes were calculated with 95% confidence interval (CIs).

RESULTS

Our search strategy identified 809 studies of which 32 studies met the inclusion criteria. Reduced rectal pain thresholds was more common in IBS patients compared to healthy controls with an effect size of 1.00 95% CIs (0.77-1.24) (p < 0.0001) (I²  = 78.6%). The pediatric IBS population had lower pain thresholds than adult IBS populations (p = 0.05) but no difference based on IBS diagnostic criteria, subtype or sex.

CONCLUSION & INFERENCES

The results suggest that reduced rectal pain threshold to experimental stimulation is far more common in IBS patients than healthy controls. Further research is required to understand the pathophysiological and therapeutic implications of rectal sensitivity such as its role in measuring response to treatment and prognosis in IBS.

Italian guidelines for the management of irritable bowel syndrome: Joint Consensus from the Italian Societies of: Gastroenterology and Endoscopy (SIGE), Neurogastroenterology and Motility (SINGEM), Hospital Gastroenterologists and Endoscopists (AIGO), Digestive Endoscopy (SIED), General Medicine (SIMG), Gastroenterology, Hepatology and Pediatric Nutrition (SIGENP) and Pediatrics (SIP)

The irritable bowel syndrome (IBS) is a chronic disorder of gut-brain interaction. IBS is still associated with areas of uncertainties, especially regarding the optimal diagnostic work-up and the more appropriate management. Experts from 7 Italian Societies conducted a Delphi consensus with literature summary and voting process on 27 statements. Recommendations and quality of evidence were evaluated using the grading of recommendations, assessment, development, and evaluation (GRADE) criteria. Consensus was defined as >80% agreement and reached for all statements. In terms of diagnosis, the consensus supports a positive diagnostic strategy with a symptom-based approach, including the psychological comorbidities assessment and the exclusion of alarm symptoms, together with the digital rectal examination, full blood count, C-reactive protein, serology for coeliac disease, and fecal calprotectin assessment. Colonoscopy should be recommended in patients with alarm features. Regarding treatment, the consensus strongly supports a dietary approach for patients with IBS, the use of soluble fiber, secretagogues, tricyclic antidepressants, psychologically directed therapies and, only in specific IBS subtypes, rifaximin. A conditional recommendation was achieved for probiotics, polyethylene glycol, antispasmodics, selective serotonin reuptake inhibitors and, only in specific IBS subtypes, 5-HT3 antagonists, 5-HT4 agonists, bile acid sequestrants.

The association between dietary acid load and odds and severity of irritable bowel syndrome in adults

No study has been conducted to investigate the association between dietary acid load and irritable bowel syndrome (IBS). So, this cross-sectional study was performed to investigate the association between dietary acid load and odds of IBS, its severity, and IBS subtypes. A sample of 3362 Iranian subjects was selected from health centers in Isfahan province. A validated semi-quantitative food frequency questionnaire (DS-FFQ) was applied to estimate dietary intakes. The dietary acid load was measured using net endogenous acid production (NEAP), dietary acid load (DAL), and potential renal acid load (PRAL) scores. In crude models, the highest compared with the lowest category of the PRAL score was significantly associated with increased odds of IBS severity in participants with BMI ≥ 25 (kg/m²) (OR = 1.54; 95% CI = (1.03-2.32). Also, the results indicated a significant positive association between the PARL and odds of mixed subtype of IBS (OR = 1.74; 95% CI = (1.11-2.74); P trend = 0.02). In propensity score-adjusted model with potential confounders, only a positive association was found between PRAL and odds of mixed subtype of IBS (OR = 1.78; 95% CI = (1.05-3.00); P trend = 0.03). The DAL and NEAP scores tended to show non-significant similar findings. This study indicates that dietary acid load might be associated with odds of mixed type of IBS. However, further research is warranted to infer these findings.

Unraveling the role of Epac1-SOCS3 signaling in the development of neonatal-CRD-induced visceral hypersensitivity in rats

Aims

Visceral hypersensitivity in irritable bowel syndrome (IBS) is widespread, but effective therapies for it remain elusive. As a canonical anti‐inflammatory protein, suppressor of cytokine signaling 3 (SOCS3) reportedly relays exchange protein 1 directly activated by cAMP (Epac1) signaling and inhibits the intracellular response to inflammatory cytokines. Despite the inhibitory effect of SOCS3 on the pro‐inflammatory response and neuroinflammation in PVN, the systematic investigation of Epac1‐SOCS3 signaling involved in visceral hypersensitivity remains unknown. This study aimed to explore Epac1‐SOCS3 signaling in the activity of hypothalamic paraventricular nucleus (PVN) corticotropin‐releasing factor (CRF) neurons and visceral hypersensitivity in adult rats experiencing neonatal colorectal distension (CRD).

Methods

Rats were subjected to neonatal CRD to simulate visceral hypersensitivity to investigate the effect of Epac1‐SOCS3 signaling on PVN CRF neurons. The expression and activity of Epac1 and SOCS3 in nociceptive hypersensitivity were determined by western blot, RT‐PCR, immunofluorescence, radioimmunoassay, electrophysiology, and pharmacology.

Results

In neonatal‐CRD‐induced visceral hypersensitivity model, Epac1 and SOCS3 expressions were downregulated and IL‐6 levels elevated in PVN. However, infusion of Epac agonist 8‐pCPT in PVN reduced CRF neuronal firing rates, and overexpression of SOCS3 in PVN by AAV‐SOCS3 inhibited the activation of PVN neurons, reduced visceral hypersensitivity, and precluded pain precipitation. Intervention with IL‐6 neutralizing antibody also alleviated the visceral hypersensitivity. In naïve rats, Epac antagonist ESI‐09 in PVN increased CRF neuronal firing. Consistently, genetic knockdown of Epac1 or SOCS3 in PVN potentiated the firing rate of CRF neurons, functionality of HPA axis, and sensitivity of visceral nociception. Moreover, pharmacological intervention with exogenous IL‐6 into PVN simulated the visceral hypersensitivity.

Conclusions

Inactivation of Epac1‐SOCS3 pathway contributed to the neuroinflammation accompanied by the sensitization of CRF neurons in PVN, precipitating visceral hypersensitivity and pain in rats experiencing neonatal CRD.

Comparison of five diarrhea-predominant irritable bowel syndrome (IBS-D) rat models in the brain-gut-microbiota axis

The brain-gut-microbiota (BGM) axis is known to be essential for diarrhea-predominant irritable bowel syndrome (IBS-D). In order to evaluate the effects of IBS-D rat models (the central sensitization model, the peripheral sensitization model and the compound model) on the BGM axis, five models were induced in Wistar rats with 4% acetic acid (AD, dissolved 0.4 ml of AD in 9.6 ml of ultrapure water) + wrap restrain stress (WRS), 4% AD, colorectal distention (CRD), WRS, and neonatal maternal separation (NMS). Abdominal withdrawal reflex (AWR) scale scores and the moisture content of feces (MCF) were evaluated on the day of completing modeling. Body weight was measured every 7 days during modeling. Brain gut peptides, cytokine levels, the activity of spinal cord neurons, intestinal mucosal barrier function, and gut microbiota were determined after induction of IBS-D. We found intervention with 4% AD + WRS, 4% AD, CRD, WRS, and NMS induced a similar course of effects on the BGM axis. Among the five models, AWR scores (60 mmHg, 80 mmHg) were all increased. The levels of 5-hydroxytryptamine, corticotropin-releasing factor, substance P, and calcitonin gene-related protein in serum rapidly increased, whereas that of neuropeptide Y decreased. C-fos in the spinal cord showed increased neuronal activity. The intestinal permeability was increased and the composition and structure of gut microbiota were changed. In conclusion, the five models could cause changes in BGM axis, but the 4% AD + WRS model was closer to the changes BGM axis of post-inflammatory models of IBS-D.

ROS-responsive thioketal-linked alginate/chitosan carriers for irritable bowel syndrome with diarrhea therapy

A colon-specific carrier that can protect drugs from the destruction in the gastrointestinal tract is critical for treating irritable bowel syndrome with diarrhea (IBS-D). In this study, chitosan was cross-linked by the thioketal (TK) bond to serve as a ROS-sensitive core of microspheres. Then the chitosan core was coated with an alginate shell. The alginate/chitosan microspheres can protect puerarin against the destruction and elimination in the gastrointestinal tract and release puerarin at the lesion sites in large quantities. The microspheres were characterized using differential scanning calorimetry, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The swelling study showed that microspheres would shrink in an acidic environment. The in vitro release analysis indicated that little puerarin was released at gastric pH but burst release was observed in simulated colonic fluid containing H₂O₂. Fluorescent tracer revealed that the fluorescence of microspheres lasted up to 30 h in the colon, which was beneficial to prolong the action time between puerarin and colon. The in vivo studies indicated that puerarin-loaded microspheres are more effective in the treatment of IBS-D than free puerarin. Altogether, the ROS-responsive alginate/chitosan microspheres may be a promising strategy for IBS-D.

Identification of a Pain-Specific Gene Expression Profile for Pediatric Recurrent Abdominal Pain

Objectives: Functional Abdominal Pain (FAP) and Irritable Bowel Syndrome (IBS) are common recurrent abdominal pain diagnoses with the hallmark, lack of inflammation. To identify a biological signature for IBS/FAP in the colon, this study used genetic profiling to uncover gene expression changes associated with IBS/FAP and abdominal pain. Methods: Patients (8 to 17 years) newly diagnosed with IBS or FAP were enrolled in the study. At diagnostic colonoscopy, three rectal biopsies were collected, and gene expression analysis was performed using a Qiagen PCR Array. Relative fold difference in gene expression for 84 pain-associated genes was calculated using the 2-ΔΔ Cq method compared with pain-free controls. Factors affecting pain burden (Pain Burden Interview; PBI) were analyzed, including age, sex, rectal inflammation, and gene expression. Data were analyzed using multiple stepwise linear regression and 2-tailed t tests (P ≤ 0.05). Results: Of the 22 total patients in the study, 19 were diagnosed with either IBS-Constipation (frequency of 5.26%), IBS-Diarrhea (47.37%), IBS-Mixed (10.53%), or FAP (36.84%). IBS/FAP patients reported significantly higher pain burden at the time of diagnosis compared to pain-free controls (p < 0.001), as well as significantly higher abdominal pain (p = 0.01). Of the 84 genes, expression of GRIN1 (p = 0.02), MAPK3 (p = 0.04), P2X4 (p = 0.04), and PTGES3 (p = 0.02) were all significantly associated with PBI score. Discussion: Abdominal pain associated with IBS/FAP in pediatric patients may be linked to the expression of GRIN1, MAPK3, P2X4, and PTGES3, pointing to potential novel therapeutic targets for management of recurring abdominal pain.

Incidence of Cancer in Patients with Irritable Bowl Syndrome

(1) Background: Irritable bowel syndrome (IBS) represents one of the most common disorders of gut–brain interaction (DGBI). As recent data has suggested an increased cancer incidence for IBS patients, there is an ongoing debate whether IBS might be associated with a risk of cancer development. In the present study, we evaluated and compared incidence rates of different malignancies including gastrointestinal cancer in a large cohort of outpatients, with or without IBS, treated in general practices in Germany. (2) Methods: We matched a cohort of 21,731 IBS patients from the IQVIA Disease Analyzer database documented between 2000 and 2019 in 1284 general practices to a cohort of equal size without IBS. Incidence of cancer diagnoses were evaluated using Cox regression models during a 10-year follow-up period. (3) Results: In 11.9% of patients with IBS compared to 8.0% without IBS, cancer of any type was diagnosed within 10 years following the index date (p < 0.001). In a regression analysis, this association was confirmed in female (HR: 1.68, p < 0.001) and male (HR = 1.57, p < 0.001) patients as well as in patients of all age groups. In terms of cancer entity, 1.9% of patients with and 1.3% of patients without IBS were newly diagnosed with cancer of digestive organs (p < 0.001). Among non-digestive cancer entities, the strongest association was observed for skin cancer (HR = 1.87, p < 0.001), followed by prostate cancer in men (HR = 1.81, p < 0.001) and breast cancer in female patients (HR = 1.80, p < 0.001). (4) Conclusion: Our data suggest that IBS might be associated with cancer of the digestive organs as well as with non-digestive cancer entities. However, our findings do not prove causality and further research is warranted as the association could be attributed to life style factors that were not documented in the database.

Rectal Hypersensitivity in Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Abdominal pain is a key symptom of inflammatory bowel disease (IBD), particularly in active IBD, but also occurs in patients with quiescent disease suggesting that mechanisms other than active inflammation may be responsible. Putative hypothesis to explain chronic abdominal pain in patients with quiescent IBD includes crossover with irritable bowel syndrome where rectal hypersensitivity is common and has pathophysiological implications. In contrast, in IBD, the role of rectal hypersensitivity has not been established. We aimed to determine if rectal hypersensitivity was more common in IBD compared to a healthy control population. We searched MEDLINE and EMBASE databases (1970-2018). Prospective studies that measured pain/discomfort thresholds to mechanical rectal stimuli in IBD and healthy controls were included. Data were pooled for meta-analysis and effect sizes were calculated with 95% confidence intervals (CIs). Our search strategy identified 222 citations of which 8 met the inclusion criteria, covering 133 individuals with IBD (67 men), aged between 10 and 77 compared to 99 healthy controls (55 men), aged between 10 and 67. The prevalence of rectal hypersensitivity in IBD compared to healthy controls was similar with an effect size of 0.59 (95% CIs: -0.27 to 1.44, P = .16, I ² = 87.3%). Subgroup analysis did show a significant effect size for patients compared to healthy controls with active disease (1.32) but not for quiescent disease (-0.02). These results suggest that reduced rectal pain thresholds to experimental stimulation are not seen in IBD populations except during active flares of the disease. Further research is required to understand the pathophysiology of chronic abdominal pain in quiescent IBD populations with and without chronic abdominal pain to identify appropriate management strategies.

Irritable Bowel Syndrome and Me: A Sworn Rivalry

“Three more hours”, I tell myself as I find my way to the exam hall. I see a bunch of my classmates cramming for the last minute, and here I am, in a corner, reminding myself that it's just three more hours till I get away from this horror. Irritable Bowel Syndrome is a gastrointestinal disorder in which there is dull achy lower abdominal pain associated with either diarrhea or constipation. Though it has high prevalence, it is still an underrated disease which can be easily missed in clinical settings.

Effects of Rifaximin on Luminal and Wall-Adhered Gut Commensal Microbiota in Mice

Rifaximin is a broad-spectrum antibiotic that ameliorates symptomatology in inflammatory/functional gastrointestinal disorders. We assessed changes in gut commensal microbiota (GCM) and Toll-like receptors (TLRs) associated to rifaximin treatment in mice. Adult C57BL/6NCrl mice were treated (7/14 days) with rifaximin (50/150 mg/mouse/day, PO). Luminal and wall-adhered ceco-colonic GCM were characterized by fluorescent in situ hybridization (FISH) and microbial profiles determined by terminal restriction fragment length polymorphism (T-RFLP). Colonic expression of TLR2/3/4/5/7 and immune-related markers was assessed (RT-qPCR). Regardless the period of treatment or the dose, rifaximin did not alter total bacterial counts or bacterial biodiversity. Only a modest increase in Bacteroides spp. (150 mg/1-week treatment) was detected. In control conditions, only Clostridium spp. and Bifidobacterium spp. were found attached to the colonic epithelium. Rifaximin showed a tendency to favour their adherence after a 1-week, but not 2-week, treatment period. Minor up-regulation in TLRs expression was observed. Only the 50 mg dose for 1-week led to a significant increase (by 3-fold) in TLR-4 expression. No changes in the expression of immune-related markers were observed. Rifaximin, although its antibacterial properties, induces minor changes in luminal and wall-adhered GCM in healthy mice. Moreover, no modulation of TLRs or local immune systems was observed. These findings, in normal conditions, do not rule out a modulatory role of rifaximin in inflammatory and or dysbiotic states of the gut.

ACG Clinical Guideline: Management of Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a highly prevalent, chronic disorder that significantly reduces patients' quality of life. Advances in diagnostic testing and in therapeutic options for patients with IBS led to the development of this first-ever American College of Gastroenterology clinical guideline for the management of IBS using Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. Twenty-five clinically important questions were assessed after a comprehensive literature search; 9 questions focused on diagnostic testing; 16 questions focused on therapeutic options. Consensus was obtained using a modified Delphi approach, and based on GRADE methodology, we endorse the following: We suggest that a positive diagnostic strategy as compared to a diagnostic strategy of exclusion be used to improve time to initiating appropriate therapy. We suggest that serologic testing be performed to rule out celiac disease in patients with IBS and diarrhea symptoms. We suggest that fecal calprotectin be checked in patients with suspected IBS and diarrhea symptoms to rule out inflammatory bowel disease. We recommend a limited trial of a low fermentable oligosaccharides, disacchardies, monosaccharides, polyols (FODMAP) diet in patients with IBS to improve global symptoms. We recommend the use of chloride channel activators and guanylate cyclase activators to treat global IBS with constipation symptoms. We recommend the use of rifaximin to treat global IBS with diarrhea symptoms. We suggest that gut-directed psychotherapy be used to treat global IBS symptoms. Additional statements and information regarding diagnostic strategies, specific drugs, doses, and duration of therapy can be found in the guideline.

IBS-Symptoms in IBD Patients-Manifestation of Concomitant or Different Entities

Irritable bowel syndrome (IBS) is a functional heterogenous disease with a multifactorial pathogenesis. It is characterized by abdominal pain, discomfort, and alteration in gut motility. The occurrence of similar symptoms was observed in patients in clinical remission of inflammatory bowel diseases (IBD) that is Crohn's disease (CD) and ulcerative colitis (UC), which pathogenesis is also not fully understood. Hence, arose the question if these symptoms are "true IBS" imposed on IBD, or is it a subclinical form of IBD or even pre-IBD? In this article, based on a narrative overview of the literature, we try to find an answer to this query by discussing the pathogenesis and overlaps between these conditions.

Diagnostic accuracy of faecal calprotectin in a symptom-based algorithm for early diagnosis of inflammatory bowel disease adjusting for differential verification bias using a Bayesian approach

BACKGROUND

Diagnostic delay in IBD is a major problem and diagnosis is frequently arrived when irreversible damage has already occurred. This study evaluated accuracy of faecal calprotectin (fCAL) integrated with diagnostic criteria for early diagnosis of IBD in a primary care setting.

METHODS

General practitioners (GPs) were trained to recognize alarm symptoms for IBD classified as major and minor criteria. Fulfilment of one major or at least two minor criteria was followed by free fCAL testing and a visit by an IBD specialist and follow-up over 12 months. All patients with positive fCAL testing, i.e., ≥70 μg/g underwent colonoscopy. The diagnostic accuracy of fCAL was estimated after adjusting for differential-verification bias following a Bayesian approach.

RESULTS

Thirty-four GPs participated in the study and 133 patients were tested for fCAL between July 2016 and August 2017. Positivity of fCAL was seen in 45/133 patients (34%) and a final IBD diagnosis was made in 10/45 (22%). According to the threshold of 70 μg/g, fCAL achieved a sensitivity of 74.8% (95%CI: 39.10-96.01%), a specificity of 70.4% (95%CI: 61.76-78.16%) and an overall diagnostic accuracy of 70.6% (95%CI: 61.04-78.37%). As for prognostic accuracy, despite positive predictive value being low, 21.9% (95%CI: 11.74-35.18%), the negative predictive value was definitely higher: 96.2% (95%CI: 84.96-99.51%).

CONCLUSIONS

fCAL with a threshold set at 70 μg/g seems to represent a potentially reliable negative test to be used in primary care settings for patients with symptoms suggestive of IBD.

Acute stress disrupts intestinal homeostasis via GDNF-RET

Objectives

Enterochromaffin (EC) cells have been associated with functional gastrointestinal disorders such as IBS. Recently, we found that glial cell‐derived neurotrophic factor (GDNF)‐rearranged during transfection (RET) localized in EC cells in human colonic epithelia. Here, we examine the role of GDNF‐RET in the pathophysiology of diarrhoea‐predominant irritable bowel syndrome (IBS‐D).

Materials and Methods

GDNF was assessed by ELISA and immunohistochemistry in biopsies from IBS‐D patients and healthy controls. Stress was induced by using a wrap‐restraint stress (WRS) procedure to serve as an acute stress‐induced IBS model. The function of GDNF‐RET axis to intestinal stem cell (ISC) homeostasis, and EC cell numbers were assessed in vivo and in vitro.

Results

GDNF‐RET was expressed in EC cells in human colon. GDNF was significantly increased in IBS‐D patients. WRS mice showed increased GDNF‐RET levels in colon. WRS induced visceral hypersensitivity by expanding of ISC and differentiation of EC cell via GDNF‐RET. Furthermore, GDNF‐treated mice recapitulated the phenotype of WRS mice. In vitro, GDNF treatment amplified Wnt signal and increased serotonin levels in colonic organoids in a dose‐dependent manner.

Conclusions

We identified GDNF‐RET was presented in colonic epithelium of patients with IBS‐D. GDNF‐RET played important roles in regulating ISC and EC cell differentiation. Our findings, thus, provide RET inhibitor as new therapeutic targets for treatment of patients with IBS‐D.

Targeting gut barrier dysfunction with phytotherapies: Effective strategy against chronic diseases

The intestinal epithelial layer serves as a physical and functional barrier between the microbe-rich lumen and immunologically active submucosa; it prevents systemic translocation of microbial pyrogenic products (e.g. endotoxin) that elicits immune activation upon translocation to the systemic circulation. Loss of barrier function has been associated with chronic 'low-grade' systemic inflammation which underlies pathogenesis of numerous no-communicable chronic inflammatory disease. Thus, targeting gut barrier dysfunction is an effective strategy for the prevention and/or treatment of chronic disease. This review intends to emphasize on the beneficial effects of herbal formulations, phytochemicals and traditional phytomedicines in attenuating intestinal barrier dysfunction. It also aims to provide a comprehensive understanding of intestinal-level events leading to a 'leaky-gut' and systemic complications mediated by endotoxemia. Additionally, a variety of detectable markers and diagnostic criteria utilized to evaluate barrier improving capacities of experimental therapeutics has been discussed. Collectively, this review provides rationale for targeting gut barrier dysfunction by phytotherapies for treating chronic diseases that are associated with endotoxemia-induced systemic inflammation.

Tryptophan Metabolites Along the Microbiota-Gut-Brain Axis: An Interkingdom Communication System Influencing the Gut in Health and Disease

The ‘microbiota-gut-brain axis’ plays a fundamental role in maintaining host homeostasis, and different immune, hormonal, and neuronal signals participate to this interkingdom communication system between eukaryota and prokaryota. The essential aminoacid tryptophan, as a precursor of several molecules acting at the interface between the host and the microbiota, is fundamental in the modulation of this bidirectional communication axis. In the gut, tryptophan undergoes 3 major metabolic pathways, the 5-HT, kynurenine, and AhR ligand pathways, which may be directly or indirectly controlled by the saprophytic flora. The importance of tryptophan metabolites in the modulation of the gastrointestinal tract is suggested by several preclinical and clinical studies; however, a thorough revision of the available literature has not been accomplished yet. Thus, this review attempts to cover the major aspects on the role of tryptophan metabolites in host-microbiota cross-talk underlaying regulation of gut functions in health conditions and during disease states, with particular attention to 2 major gastrointestinal diseases, such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), both characterized by psychiatric disorders. Research in this area opens the possibility to target tryptophan metabolism to ameliorate the knowledge on the pathogenesis of both diseases, as well as to discover new therapeutic strategies based either on conventional pharmacological approaches or on the use of pre- and probiotics to manipulate the microbial flora.

Serum patterns of mir-23a and mir-181b in irritable bowel syndrome and colorectal cancer - A pilot study

Emerging evidence demonstrates that microRNAs (miRNAs) could serve as reliable biomarkers of inflammation and oncogenesis. The aim of this study was to determine whether miR-23a and miR-181b were suitable as biomarkers of irritable bowel syndrome (IBS) and colorectal cancer (CRC). Forty patients with IBS (29 females, 11 males), 33 with CRC (14 females, 19 males), and 33 healthy controls (17 females, 16 males) were prospectively included. Serum levels of miRNAs were evaluated by quantitative real-time PCR. The serum levels of miR-23a and miR-181b were significantly higher in the IBS group (p = 0.0009 and 0.004, respectively) and CRC group (p = 0.002 and 0.029, respectively) than in the control group. Serum levels of miR-23a and miR-181b were upregulated in CRC vs. IBS, but the differences did not reach statistical significance (p = 0.169 and 0.179, respectively). The miRNet and Reactome databases identified phosphatase and tensin homolog as a major common pathway, indicating inflammation as a central hallmark. Although miRNAs could serve as reliable biomarkers in clinical practice, future studies are needed to establish appropriate cut-off limits.

Influence Of Narrative Medicine-Based Health Education Combined With An Online Patient Mutual Assistance Group On The Health Of Patients With Inflammatory Bowel Disease and Arthritis

Background

Inflammatory bowel disease arthritis (IBDA) threatens patients' physical and mental health. Therefore, patients need not only physical therapy, but also adequate health education and psychological support. This study was designed to explore the effect of health education based on narrative medicine combined with an online patient mutual assistance group that was based on the physical and mental health of patients with IBDA.

Methods

A total of 120 patients with IBDA were randomly divided into four groups (30 patients per group). Patients in the control group were given routine health education on the premise of routine treatment. The three treatment groups were given health education based on narrative medicine, online patient mutual assistance group intervention, or combined intervention. Depression, sleep, arthralgia, irritable bowel syndrome (IBS) symptoms, and inflammatory factors were measured and compared before and 1 month after the intervention.

Results

Before the intervention, no significant differences were observed in baseline data between the four groups. However, after the intervention, the physical and mental health of patients who received health education based on narrative medicine or online patient mutual assistance groups was improved. Our data showed that patients in the combined intervention group experienced a better outcome.

Conclusion

Narrative medicine-based health education combined with an online patient mutual assistance group is beneficial to the physical and mental health of IBDA patients. Taken together, this model needs to be further deepened and popularized in clinical practice.

Masked bolus gluten challenge low in FODMAPs implicates nausea and vomiting as key symptoms associated with immune activation in treated coeliac disease

BACKGROUND

In patients with coeliac disease, FODMAPs in gluten-containing foods, and participant anticipation of a harmful ('nocebo') effect, may contribute to acute symptoms after gluten challenge.

AIM

To establish acute gluten-specific symptoms linked to immune activation in coeliac disease METHODS: We included 36 coeliac disease patients on a gluten-free diet receiving placebo in the RESET CeD trial. Double-blind, bolus vital wheat gluten (~6-g gluten protein) and sham challenges low in FODMAPs were consumed 2 weeks apart. Assessments included daily Coeliac Disease Patient Reported Outcome (CeD PRO) symptom scores (0-10), adverse events and serum interleukin-2 (baseline and 4 hours).

RESULTS

Median CeD PRO score for nausea increased most (sham: 0 vs gluten: 5.5; P < .001). Apart from tiredness (1 vs 4, P = .005) and headache (0 vs 2, P = .002), changes in other symptoms were small or absent. Only nausea increased significantly in occurrence with gluten (11% vs 69%, P < .001). Without nausea, only tiredness and flatulence were common after gluten. Nausea (6% vs 61%, P < .001; median onset: 1:34 hours) and vomiting (0% vs 44%, P < .001; 1:51 hours) were the only adverse events more common with gluten than sham. Interleukin-2 was always below the level of quantitation (0.5 pg/mL) at baseline, and after sham. Interleukin-2 was elevated after gluten in 97% of patients (median fold-change: 20), and correlated with severity of nausea (r_s  = .49, P = .0025) and occurrence of vomiting (P = .0005).

CONCLUSIONS

Nausea and vomiting are relatively specific indicators of acute gluten ingestion, and correlate with immune activation. IBS-like symptoms without nausea are unlikely to indicate recent gluten exposure.

Can the CalproQuest predict a positive Calprotectin test? A prospective diagnostic study

Background

Diagnosis of inflammatory bowel disease (IBD) in primary care (PC) is challenging and associated with a considerable diagnostic delay. Using a calprotectin test for any PC patient with abdominal complaints would cause significant costs. The 8-item-questionnaire CalproQuest was developed to increase the pre-test probability for a positive Calprotectin. It is a feasible instrument to assess IBD in PC, but has not yet been evaluated in clinical routine. This study, therefore, aimed to validate whether the CalproQuest increases pretest-probability for a positive fecal Calprotectin.

Methods

Prospective diagnostic trial. The CalproQuest consists of 4 major and 4 minor questions suggestive for IBD. It is considered positive if ≥ 2 major or 1 major and 2 minor criteria are positive. Primary outcome: Sensitivity and specificity of the CalproQuest for Calprotectin levels ≥ 50 μg/g and for positive IBD diagnosis among patients referred to endoscopic evaluation at secondary care level. Secondary finding: Patient-reported diagnostic delay.

Results

156 patients from 7 study centers had a complete CalproQuest and fecal Calprotectin test. The sensitivity and specificity of CalproQuest for Calprotectin ≥ 50 μg/g was 36% and 57%. The sensitivity and specificity of the CalproQuest for positive IBD diagnosis was 37% and 67%. The diagnostic delay was 61 months (SD 125.2).

Conclusion

In this prospective diagnostic study, the sensitivity and specificity of CalproQuest for Calprotectin levels ≥ 50 μg/g and positive IBD diagnosis were poor. Additional prospective studies concerning the ideal cut-off values, validity and cost-effectiveness of a combined use with the Calprotectin test in the PC setting are necessary.

Hypothesis: Mechanism of irritable bowel syndrome in inflammatory bowel disease

Functional bowel symptoms can be occurred during remission from inflammatory bowel disease. In this case, a low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet is effective for the amelioration or prevention of symptoms. However, the reason is not fully explained. This report proposes a hypothesis regarding the entire process in which inflammatory bowel disease with IBS-like symptoms (IBD-IBS) causes symptoms. A detailed process was assumed, starting from high pressure in the lumen and finally to abdominal symptoms. In this process, relationships were linked based on interactions such as ischemia, compliance, pain threshold, visceral hypersensitivity, mast cells, and permeability reported in IBD-IBS. In the process mapping, to understand the relationship between the amount of gas increased by FODMAP and ischemia, the hydrodynamic hypothesis and Ritchie's hypothesis were adapted. Ischemia in dilated intestines due to an increase in gas volume can induce excessive spasms via the mast cells and show the whole process of lowering the pain threshold. From the standpoint of the mechanism of IBD-IBS, the origin trigger may be FODMAP. Therefore, a low-FODMAP diet is recommended to relieve and prevent IBD-IBS symptoms.

Identification of an intestinal microbiota signature associated with hospitalized patients with diarrhea

As an important global health challenge, diarrhea kills nearly two million people each year. Postinfectious irritable bowel syndrome (IBS) usually manifests itself as the diarrhea-predominant subtype. Small intestinal bacterial overgrowth has been observed more frequently in patients with IBS compared to healthy controls. However, the pathophysiology of IBS is not fully understood, and based on recent evidences, altered gut microbiota is involved in the pathogenesis of IBS. Therefore, we aimed to compare the microbiome in hospitalized patients with diarrhea and healthy individuals. Thirty patients and 10 healthy controls were included into this case-control study. Microbial count was performed using quantitative real-time polymerase chain reaction method using bacterial 16S rRNA gene. Clostridium cluster IV and Bacteroides were significantly more frequent in the patients compared with the healthy individuals (p = 0.02 and 0.023, respectively). However, the quantity of Enterococcus and Bifidobacterium groups were significantly higher in healthy controls than in diarrheal group (p = 0.000076 and 0.001, respectively). The results showed that the number of bacteria in all bacterial groups was significantly different between healthy individuals and diabetic group, whereas the difference between the healthy group and IBS was not significant for Bifidobacterium group. The findings of this study outlined the relationship between diarrhea, IBS, and diabetes disease and bacterial composition. It could be concluded that modifying the bacterial composition by probiotics can be helpful in the control and management of the mentioned disease.

Feasibility of an 8-item questionnaire for early diagnosis of inflammatory bowel disease in primary care

AIMS

Diagnosis of inflammatory bowel disease (IBD) is often associated with a diagnostic delay. Although faecal calprotectin is a helpful screening tool, the widespread use in primary care (PC) may not be appropriate due to the low prevalence of IBD in this setting. To increase pretest probability for a positive calprotectin test, an 8-item questionnaire (CalproQuest) was tested for its feasibility and acceptability in PC.

METHODS

Population: PC patients with unspecific gastrointestinal complaints for at least 2 weeks. The CalproQuest consists of four major and four minor questions specific for IBD. It is considered positive if greater than or equal to two major or one major and two minor criteria are positive.

PRIMARY OUTCOME

feasibility of CalproQuest, secondary outcome: patient's acceptance of stool sampling.

RESULTS

Of 95 patients with a complete CalproQuest 52 (54.7%) were positive, 39 (41.1%) fulfilled two major and 13 (13.7%) one major and greater than or equal to two minor criteria. Twenty-seven general practitioners completed 83 (87.4%) questionnaires on feasibility which was assessed positive. Eighty-two patients (86.3%) completed questionnaires on acceptance which was high.

CONCLUSION

The CalproQuest is a feasible instrument for assessing IBD in PC. Further prospective studies concerning validity and cost effectiveness of a combined use with the calprotectin test in this setting are necessary.

The role of the microbiota in infectious diseases

The human body is colonized by a diverse community of microorganisms collectively referred to as the microbiota. Here, we describe how the human microbiota influences susceptibility to infectious diseases using examples from the respiratory, gastrointestinal and female reproductive tract. We will discuss how interactions between the host, the indigenous microbiota and non-native microorganisms, including bacteria, viruses and fungi, can alter the outcome of infections. This Review Article will highlight the complex mechanisms by which the microbiota mediates colonization resistance, both directly and indirectly, against infectious agents. Strategies for the therapeutic modulation of the microbiota to prevent or treat infectious diseases will be discussed, and we will review potential therapies that directly target the microbiota, including prebiotics, probiotics, synbiotics and faecal microbiota transplantation.

The possible role of bacteria, viruses, and parasites in initiation and exacerbation of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a prolonged and disabling functional gastrointestinal disorder with the incidence rate of 18% in the world. IBS could seriously affect lifetime of patients and cause high economic burden on the community. The pathophysiology of the IBS is hardly understood, whereas several possible mechanisms, such as visceral hypersensitivity, irregular gut motility, abnormal brain-gut relations, and the role of infectious agents, are implicated in initiation and development of this syndrome. Different studies demonstrated an alteration in B-lymphocytes, mast cells (MC), T-lymphocytes, and cytokine concentrations in intestinal mucosa or systemic circulation that are likely to contribute to the formation of the IBS. Therefore, IBS could be developed in those with genetic predisposition. Infections' role in initiation and exacerbation of IBS has been investigated by quite several clinical studies; moreover, the possible role of some pathogens in development and exacerbation of this disease has been described. It appears that the main obligatory pathogens correspond with the IBS disease, Clostridium difficile, Escherichia coli, Mycobacterium avium subspecies paratuberculosis, Campylobacter concisus, Campylobacter jejuni, Chlamydia trachomatis, Helicobacter pylori, Pseudomonas aeruginosa, Salmonella spp, Shigella spp, and viruses, particularly noroviruses. A number of pathogenic parasites (Blastocystis, Dientamoeba fragilis, and Giardia lamblia) may also be involved in the progression and exacerbation of the disease. Based on the current knowledge, the current study concludes that the most common bacterial, viral, and parasitic pathogens may be involved in the development and progression of IBS.

Oral treatment with plecanatide or dolcanatide attenuates visceral hypersensitivity via activation of guanylate cyclase-C in rat models

AIM

To investigate the effects of plecanatide and dolcanatide on maintenance of paracellular permeability, integrity of tight junctions and on suppression of visceral hypersensitivity.

METHODS

Transport of fluorescein isothiocyanate (FITC)-dextran was measured to assess permeability across cell monolayers and rat colon tissues. Effects of plecanatide and dolcanatide on the integrity of tight junctions in Caco-2 and T84 monolayers and on the expression and localization of occludin and zonula occludens-1 (ZO-1) were examined by immunofluorescence microscopy. Anti-nociceptive activity of these agonists was evaluated in trinitrobenzene sulfonic acid (TNBS)-induced inflammatory as well as in non-inflammatory partial restraint stress (PRS) rat models. Statistical significance between the treatment groups in the permeability studies were evaluated using unpaired t-tests.

RESULTS

Treatment of T84 and Caco-2 monolayers with lipopolysaccharide (LPS) rapidly increased permeability, which was effectively suppressed when monolayers were also treated with plecanatide or dolcanatide. Similarly, when T84 and Caco-2 monolayers were treated with LPS, cell surface localization of tight junction proteins occludin and ZO-1 was severely disrupted. When cell monolayers were treated with LPS in the presence of plecanatide or dolcanatide, occludin and ZO-1 were localized at the cell surface of adjoining cells, similar to that observed for vehicle treated cells. Treatment of cell monolayers with plecanatide or dolcanatide without LPS did not alter permeability, integrity of tight junctions and cell surface localization of either of the tight junction proteins. In rat visceral hypersensitivity models, both agonists suppressed the TNBS-induced increase in abdominal contractions in response to colorectal distension without affecting the colonic wall elasticity, and both agonists also reduced colonic hypersensitivity in the PRS model.

CONCLUSION

Our results suggest that activation of GC-C signaling might be involved in maintenance of barrier function, possibly through regulating normal localization of tight junction proteins. Consistent with these findings, plecanatide and dolcanatide showed potent anti-nociceptive activity in rat visceral hypersensitivity models. These results imply that activation of GC-C signaling may be an attractive therapeutic approach to treat functional constipation disorders and inflammatory gastrointestinal conditions.

Risk factors for diagnostic delay in Crohn's disease and their impact on long-term complications: how do they differ in a tuberculosis endemic region?

BACKGROUND

The diagnosis of Crohn's disease (CD) can be delayed in clinical practice. In tuberculosis endemic areas, empirical anti-tubercular therapy further delays treatment.

AIM(S)

To assess risk factors for diagnostic delay and its impact on the long-term complications of Crohn's disease in India where tuberculosis is endemic.

METHODS

Data from a large prospectively established inflammatory bowel disease registry were analysed retrospectively. The time from onset of symptoms to diagnosis (diagnostic delay) was calculated and categorised into two groups based on median diagnostic delay. The risk factors for delay including anti-tubercular therapy were analysed. Logistic regression analysis was done to assess impact of diagnostic delay on development of stenotic and fistular complications including need for surgery.

RESULTS

Seven hundred and twenty Crohn's disease patients (60.3% male, median: 28 years) were included. Main outcome measures were stenosis, fistula and need for surgery. Subjects with diagnostic delay >18 months (median) developed significantly higher stenotic complications and surgery (OR 4.12; 95% CI: 2.74-6.33, P < 0.001 and OR 2.41, 95% CI: 1.68-3.42, P < 0.001), respectively, compared to those ≤18 months. There was no difference in the development of fistulous complications. 193/720 (27%) received anti-tubercular therapy which significantly contributed to diagnostic delay (OR: 2.47; 95% CI: 1.76-3.47, P < 0.001) with 47% showing initial clinical response (Crohn's disease activity index- CDAI decrease >100). Moreover, the incidence of stenotic complications was significantly higher in patients who had received prior anti-tubercular therapy (55/193 (28.49%) vs 78/527 (14.8%), P < 0.001, OR: 2.60, 95% CI: 1.64-4.12).

CONCLUSIONS

Diagnostic delay in Crohn's disease is associated with significantly higher stenotic complications and need for surgery. Empirical anti-tubercular therapy is the single largest contributor to diagnostic delay in tuberculosis endemic areas. Despite initial clinical response to anti-tubercular therapy, long-term stenotic complications are higher.

Glucagon-like peptide-1 analog, liraglutide, improves visceral sensation and gut permeability in rats

BACKGROUND AND AIM

A glucagon-like peptide-1 analog, liraglutide, has been reported to block inflammatory somatic pain. We hypothesized that liraglutide attenuates lipopolysaccharide (LPS)-induced and repeated water avoidance stress (WAS)-induced visceral hypersensitivity and tested the hypothesis in rats.

METHODS

The threshold of the visceromotor response induced by colonic balloon distention was measured to assess visceral sensation. Colonic permeability was determined in vivo by quantifying the absorbed Evans blue spectrophotometrically, which was instilled in the proximal colon for 15 min. The interleukin-6 level in colonic mucosa was also quantified using ELISA.

RESULTS

Subcutaneously injected LPS (1 mg/kg) reduced the visceromotor response threshold after 3 h. Liraglutide (300 μg/kg subcutaneously) at 15 h and 30 min before injecting LPS eliminated LPS-induced allodynia. It also blocked the allodynia induced by repeated water avoidance stress for 1 h for three consecutive days. Neither vagotomy nor naloxone altered the antinociceptive effect of liraglutide, but N^G -nitro-L-arginine methyl ester, a nitric oxide synthesis inhibitor, blocked it. LPS increased colonic permeability and the interleukin-6 level, and the analog significantly inhibited these responses.

CONCLUSIONS

This study suggests that liraglutide blocked LPS-induced visceral allodynia, which may be a nitric oxide-dependent response, and was probably mediated by inhibiting pro-inflammatory cytokine production and attenuating the increased gut permeability. Because the LPS-cytokine system is considered to contribute to altered visceral sensation in irritable bowel syndrome, these results indicate the possibility that liraglutide can be useful for treating this disease.

The role of inflammation in irritable bowel syndrome (IBS)

Irritable bowel syndrome (IBS) is a complex, functional gastrointestinal disorder characterized by chronic abdominal pain or discomfort and altered bowel habits. Despite the global prevalence and disease burden of IBS, its underlying pathophysiology remains unclear. Inflammation may play a pathogenic role in IBS. Studies have highlighted the persistence of mucosal inflammation at the microscopic and molecular level in IBS, with increased recruitment of enteroendocrine cells. Substantial overlaps between IBS and inflammatory bowel disease have also been reported. This review thus aimed to discuss the body of evidence pertaining to the presence of mucosal inflammation in IBS, its putative role in the disease process of IBS, and its clinical relevance. Increased mast cell density and activity in the gut may correlate with symptoms of visceral hypersensitivity. As evidenced by patients who develop postinfectious IBS, infective gastroenteritis could cause systemic inflammation and altered microbiome diversity, which in turn perpetuates a cycle of chronic, low-grade, subclinical inflammation. Apart from mucosal inflammation, neuroinflammation is probably involved in the pathophysiology of IBS via the "gut-brain" axis, resulting in altered neuroendocrine pathways and glucocorticoid receptor genes. This gives rise to an overall proinflammatory phenotype and dysregulated hypothalamic-pituitary-adrenal axis and serotonergic (5-HT) functioning, which could, at least in part, account for the symptoms of IBS. Although a definite and reproducible pattern of immune response has yet to be recognized, further research into anti-inflammatories may be of clinical value.

Repeated water avoidance stress induces visceral hypersensitivity: Role of interleukin-1, interleukin-6, and peripheral corticotropin-releasing factor

BACKGROUND AND AIM

Repeated water avoidance stress (WAS) induces visceral hypersensitivity. Additionally, it is also known to activate corticotropin-releasing factor (CRF), mast cells, and pro-inflammatory cytokines systems, but their precise roles on visceral sensation have not been determined definitely. The aim of the study was to explore this issue.

METHODS

Abdominal muscle contractions induced by colonic balloon distention, that is, visceromotor response (VMR) was detected electrophysiologically in conscious rats. WAS or sham stress as control for 1 h daily was loaded, and the threshold of VMR was determined before and at 24 h after the stress.

RESULTS

Repeated WAS for three consecutive days reduced the threshold of VMR, but sham stress did not induce any change. Astressin, a CRF receptor antagonist (50 μg/kg) intraperitoneally (ip) at 10 min before each WAS session, prevented the visceral allodynia, but the antagonist (200 μg/kg) ip at 30 min and 15 h before measurement of the threshold after completing 3-day stress session did not modify the response. Ketotifen, a mast cell stabilizer (3 mg/kg), anakinra, an interleukin (IL)-1 receptor antagonist (20 mg/kg) or IL-6 antibody (16.6 μg/kg) ip for two times before the measurement abolished the response.

CONCLUSIONS

Repeated WAS for three consecutive days induced visceral allodynia, which was mediated through mast cells, IL-1, and IL-6 pathways. Inhibition of peripheral CRF signaling prevented but did not reverse this response, suggesting that peripheral CRF may be an essential trigger but may not contribute to the maintenance of repeated WAS-induced visceral allodynia.

Epidemiological and clinical perspectives on irritable bowel syndrome in India, Bangladesh and Malaysia: A review

Irritable bowel syndrome (IBS) is a chronic gastrointestinal disorder, common in clinic and in the community. It has a significant impact on both society and patients' quality of life. The epidemiology, clinical presentation, and management of IBS may vary in different geographical regions due to differences in diet, gastrointestinal infection, socio-cultural and psycho-social factors, religious and illness beliefs, symptom perception and reporting. Although previous reviews and consensus reports on IBS in Asia have been published, Asia is quite diverse socio-demographically. In this context, India, Bangladesh and Malaysia share some similarities, including: (1) large proportion of the population living in rural areas; (2) rapid development and associated lifestyle changes in urban areas; and (3) dietary, cultural and religious practices. The present review explores the clinical and epidemiological data on IBS from these three major nations in South and South-East Asia. In-depth review of the literature revealed important differences between IBS in the East, as revealed by studies from these three countries, and the West; these include a predominantly rural profile, differences in bowel habit and symptom profile, raising concern with regards to diagnostic criteria and subtyping of IBS, higher dietary fiber consumption, frequent lactose malabsorption, parasitosis, and possible overlap between post-infectious IBS and tropical sprue. Moreover, the current perception on difference in prevalence of the disorder in these countries, as compared to the West, might be related to variation in survey methods.

Psychological stress-induced colonic barrier dysfunction: Role of immune-mediated mechanisms

BACKGROUND

Evidence suggests that patients with irritable bowel syndrome (IBS) exhibit increases in gut permeability and alterations in tight junction (TJ) protein expression. Although psychological stress worsens IBS symptoms, the mechanisms by which stress enhances gut permeability and affects TJ protein expression remain to be determined. Here, we test the hypothesis that chronic intermittent psychological stress activates the release of proinflammatory cytokines to alter TJ proteins and promotes increased gut permeability.

METHODS

Male Fischer-344 rats were subjected to 1 hour of water avoidance stress (WAS) or SHAM stress per day for 7 days. Following the stress protocol, colonic permeability was measured via transepithelial electrical resistance (TEER) and macromolecular flux of horseradish peroxidase (HRP). In tissue isolated from rats exposed to the WAS or SHAM stress, TJ proteins claudin-2, junctional adhesion molecule-A (JAM-A) and zonula occluden-1 (ZO-1) were measured via Western blotting, histological appearance of the colonic segments was assessed via hematoxylin and eosin staining, and an inflammatory cytokine panel was quantified via quantitative reverse transcription-polymerase chain reaction.

KEY RESULTS

Repetitive daily exposure to WAS decreased the TEER, increased the macromolecular flux of HRP, and altered the expression of claudin-2, JAM-A and ZO-1 proteins within colonic tissue compared to SHAM controls. In the absence of a histologically defined inflammation, the cytokine profiles of WAS-treated animals revealed an increase in interleukin-1β and tumor necrosis factor (TNF)-α. Subsequent analysis revealed a significant positive correlation between TNF-α and expression of TJ protein claudin-2.

CONCLUSIONS & INFERENCES

Our findings suggest that chronic stress increases colonic permeability via sub-inflammatory cytokine-mediated remodeling of TJ protein expression.

Mind-Body Interventions for Pediatric Inflammatory Bowel Disease

Pediatric inflammatory bowel disease is an autoimmune disease that causes chronic inflammation of the gastrointestinal mucosa. There is emerging evidence that the brain–gut connection affects inflammatory bowel disease (IBD) patients more than previously thought. This is evidenced by comorbid mood disorders, irritable bowel symptoms concurrent with quiescent IBD, and the potential of psychosocial stressors to trigger IBD flares. Mind–body interventions such as psychotherapy, relaxation, mindfulness, biofeedback, yoga, and clinical hypnosis offer an adjunct to standard medical treatment for IBD. We will review the current evidence base for these mind–body interventions in the treatment of pediatric IBD, illustrate a case study, and offer suggestions for future research for this promising field.

Lipopolysaccharide induces visceral hypersensitivity: role of interleukin-1, interleukin-6, and peripheral corticotropin-releasing factor in rats

BACKGROUND

Lipopolysaccharide (LPS) induces visceral hypersensitivity, and corticotropin-releasing factor (CRF) also modulates visceral sensation. Besides, LPS increases CRF immunoreactivity in rat colon, which raises the possibility of the existence of a link between LPS and the CRF system in modulating visceral sensation. The present study tried to clarify this possibility.

METHODS

Visceral sensation was assessed by abdominal muscle contractions induced by colonic balloon distention, i.e., visceromotor response, electrophysiologically in conscious rats. The threshold of visceromotor response was measured before and after administration of drugs.

RESULTS

LPS at a dose of 1 mg/kg subcutaneously (sc) decreased the threshold at 3 h after the administration. Intraperitoneal (ip) administration of anakinra (20 mg/kg), an interleukin-1 (IL-1) receptor antagonist, or interleukin-6 (IL-6) antibody (16.6 µg/kg) blocked this effect. Additionally, IL-1β (10 µg/kg, sc) or IL-6 (10 µg/kg, sc) induced visceral allodynia. Astressin (200 µg/kg, ip), a non-selective CRF receptor antagonist, abolished the effect of LPS, but astressin₂-B (200 µg/kg, ip), a CRF receptor type 2 (CRF2) antagonist, did not alter it. Peripheral CRF receptor type 1 (CRF1) stimulation by cortagine (60 µg/kg, ip) exaggerated the effect of LPS, but activation of CRF2 by urocortin 2 (60 µg/kg, ip) abolished it.

CONCLUSIONS

LPS induced visceral allodynia possibly through stimulating IL-1 and IL-6 release. In addition, this effect was mediated through peripheral CRF signaling. Since the LPS-cytokine system is thought to contribute to altered visceral sensation in the patients with irritable bowel syndrome, these results may further suggest that CRF plays a crucial role in the pathophysiology of this disease.

Dietary Triggers in Irritable Bowel Syndrome: Is There a Role for Gluten?

A tight link exists between dietary factors and irritable bowel syndrome (IBS), one of the most common functional syndromes, characterized by abdominal pain/discomfort, bloating and alternating bowel habits. Amongst the variety of foods potentially evoking "food sensitivity", gluten and other wheat proteins including amylase trypsin inhibitors represent the culprits that recently have drawn the attention of the scientific community. Therefore, a newly emerging condition termed non-celiac gluten sensitivity (NCGS) or nonceliac wheat sensitivity (NCWS) is now well established in the clinical practice. Notably, patients with NCGS/NCWS have symptoms that mimic those present in IBS. The mechanisms by which gluten or other wheat proteins trigger symptoms are poorly understood and the lack of specific biomarkers hampers diagnosis of this condition. The present review aimed at providing an update to physicians and scientists regarding the following main topics: the experimental and clinical evidence on the role of gluten/wheat in IBS; how to diagnose patients with functional symptoms attributable to gluten/wheat sensitivity; the importance of double-blind placebo controlled cross-over trials as confirmatory assays of gluten/wheat sensitivity; and finally, dietary measures for gluten/wheat sensitive patients. The analysis of current evidence proposes that gluten/wheat sensitivity can indeed represent a subset of the broad spectrum of patients with a clinical presentation of IBS.

Irritable bowel syndrome and inflammatory bowel disease overlap syndrome: pieces of the puzzle are falling into place

Irritable bowel syndrome (IBS), a common gastrointestinal disorder involving the gut-brain axis, and inflammatory bowel disease (IBD), a chronic relapsing inflammatory disorder, are both increasing in incidence and prevalence in Asia. Both have significant overlap in terms of symptoms, pathophysiology, and treatment, suggesting the possibility of IBS and IBD being a single disease entity albeit at opposite ends of the spectrum. We examined the similarities and differences in IBS and IBD, and offer new thoughts and approaches to the disease paradigm.

Immune response in irritable bowel syndrome: A systematic review of systemic and mucosal inflammatory mediators

OBJECTIVE

To systematically review the available data on cytokine and immune cells in the peripheral blood and mucosal biopsy samples from patients with irritable bowel syndrome (IBS).

METHODS

From a review of the literature, data on cytokines and immune cells that had been assayed in at least three independent studies were collated and trends examined.

RESULTS

Levels of interleukin (IL)-10 tended to be decreased and those of IL-6, IL-8, tumor necrosis factor-α and IL-1β increased in the systemic circulation in IBS, while in the mucosa, IL-10 was decreased and IL-8, mast cells, enterochromaffin cells and CD3⁺ T lymphocytes were increased. However, these findings were not consistent across all studies and, in some instances, were limited to certain IBS sub-populations.

CONCLUSIONS

The interpretation of this literature is limited by several factors, such as the intrinsic heterogeneity of IBS and a lack of standardization in study design. While a number of intriguing immunological observations have been made in IBS, more work is needed before a compelling case can be made for a role for immune-mediated events in the etiology of IBS.

Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal disease with a high population prevalence. The disorder can be debilitating in some patients, whereas others may have mild or moderate symptoms. The most important single risk factors are female sex, younger age and preceding gastrointestinal infections. Clinical symptoms of IBS include abdominal pain or discomfort, stool irregularities and bloating, as well as other somatic, visceral and psychiatric comorbidities. Currently, the diagnosis of IBS is based on symptoms and the exclusion of other organic diseases, and therapy includes drug treatment of the predominant symptoms, nutrition and psychotherapy. Although the underlying pathogenesis is far from understood, aetiological factors include increased epithelial hyperpermeability, dysbiosis, inflammation, visceral hypersensitivity, epigenetics and genetics, and altered brain-gut interactions. IBS considerably affects quality of life and imposes a profound burden on patients, physicians and the health-care system. The past decade has seen remarkable progress in our understanding of functional bowel disorders such as IBS that will be summarized in this Primer.

Pathophysiology and Therapeutic Strategies for Symptomatic Uncomplicated Diverticular Disease of the Colon

Colonic diverticulosis imposes a significant burden on industrialized societies. The current accepted causes of diverticula formation include low fiber content in the western diet with decreased intestinal content and size of the lumen, leading to the transmission of muscular contraction pressure to the wall of the colon, inducing the formation of diverticula usually at the weakest point of the wall where penetration of the blood vessels occurs. Approximately 20 % of the patients with colonic diverticulosis develop abdominal symptoms (i.e., abdominal pain and discomfort, bloating, constipation, and diarrhea), a condition which is defined as symptomatic uncomplicated diverticular disease (SUDD). The pathogenesis of SUDD symptoms remains uncertain and even less is known about how to adequately manage bowel symptoms. Recently, low-grade inflammation, altered intestinal microbiota, visceral hypersensitivity, and abnormal colonic motility have been identified as factors leading to symptom development, thus changing and improving the therapeutic approach. In this review, a comprehensive search of the literature regarding on SUDD pathogenetic hypotheses and pharmacological strategies was carried out. The pathogenesis of SUDD, although not completely clarified, seems to be related to an interaction between colonic microbiota alterations, and immune, enteric nerve, and muscular system dysfunction (Cuomo et al. in United Eur Gastroenterol J 2:413-442, 2014). Greater understanding of the inflammatory pathways and gut microbiota composition in subjects affected by SUDD has increased therapeutic options, including the use of gut-directed antibiotics, mesalazine, and probiotics (Bianchi et al. in Aliment Pharmacol Ther 33:902-910, 2011; Comparato et al. in Dig Dis Sci 52:2934-2941, 2007; Tursi et al. in Aliment Pharmacol Ther 38:741-751, 2013); however, more research is necessary to validate the safety, effectiveness, and cost-effectiveness of these interventions.