Treating Chronic Abdominal Pain in Patients with Chronic Abdominal Pain and/or Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is probably the most common diagnosis in gastroenterology involving the brain-gut axis. By definition, pain is the most frequent symptom experienced by patients. It is important to understand the biopsychosocial and physiologic aspects of the disease when discussing treatment of IBS. Such therapies as lifestyle modifications, changes in diet, and cognitive behavioral therapy should be used in conjunction with pharmacotherapy rather than pharmacotherapy alone. The pathophysiologic mechanisms are reviewed in this article along with the current treatments available, in the era of growing demand for more effective treatments for the pain component of IBS.

Sex Hormones, BDNF, Leptin, and TGF-β1 in Females With IBS: A Pilot Investigation

BACKGROUND

Irritable bowel syndrome (IBS) is a chronic gastrointestinal condition predominantly affecting the female sex, and is characterized by brain-gut axis dysregulation. Relevance of hormones along the hypothalamic-pituitary gonadal axis and hypothalamic-pituitary adrenal axis to IBS symptomatology remain unclear, as does the significance of other modulators including brain derived neurotrophic factor (BDNF), leptin, and transforming growth factor βeta 1 (TGF-β1).

METHODS

Females with IBS were compared with female healthy controls (HC) on age, race, hormonal contraceptive use, body mass index, adrenocorticotropic hormone, cortisol, estradiol, follicular stimulating hormone, luteinizing hormone, progesterone, total cholesterol, Center for Epidemiological Studies Depression Scale (CES-D) and Perceived Stress Scale (PSS). BDNF, leptin, and TGF-β1 were quantified using enzyme-linked immunosorbent assay. Descriptive statistics, non-parametric techniques, and regression analyses were performed.

RESULTS

Participants with IBS (n = 12) displayed higher estradiol (p = .027) than did HC (n = 21). Direction of associations among study variables often differed between groups: BDNF and progesterone in HC (r_s = .623) and in IBS (r_s = -.723). The relationship between log (CES-D) and log (estradiol) varied by IBS status (interaction term p = 0.019).

DISCUSSION

Elevated estradiol in participants with IBS, and differential patterns of biological and psychological indices between groups, encourages further inquiry on the relevance of sex hormones, BDNF, leptin, and TGF-β1 to symptoms of IBS. Future research endeavors should conduct longitudinal quantification of sex hormones with subjective symptom assessment to facilitate insight on the pathophysiology and female sex bias in IBS.

Food-symptom diaries can generate personalized lifestyle advice for managing gastrointestinal symptoms: A pilot study

BACKGROUND

Gastrointestinal (GI) symptoms have a heterogeneous pathophysiology. Yet, clinical management uses group-level strategies. There is a need for studies exploring personalized management options in patients with GI symptoms. From diaries of GI symptoms, food intake, and psychological distress, we extracted and validated personalized lifestyle advice. Secondly, we investigated group-level GI symptom triggers using meta-analysis.

METHODS

We collected 209 diaries of GI symptoms, food intake, and psychological distress, coming from 3 cohorts of patients with GI symptoms (n = 20, 26, and 163, median lengths 24, 17, and 38 days). Diaries were split into training and test data, analyzed, and the triggers emerging from the training data were tested in the test data. In addition, we did a random effects meta-analysis on the full data to establish the most common GI symptom triggers.

KEY RESULTS

Analysis of the training data allowed us to predict symptom triggers in the test data (r = 0.27, P < .001), especially in the subset of patients with a strong global association between lifestyle factors and symptoms (r = 0.45, P < .001). Low exposure to these triggers in the test data was associated with symptom reduction (P = .043). Meta-analysis showed that caloric intake in the late evening or night predicted an increase in GI symptoms, especially bloating. Several food-symptom associations were found, whereas psychological distress did not clearly lead to more severe GI symptoms.

CONCLUSIONS & INFERENCES

Diaries of GI symptoms, food intake, and psychological distress can lead to meaningful personalized lifestyle advice in subsets of patients.

TRPM8 Channel Activation Reduces the Spontaneous Contractions in Human Distal Colon

The transient receptor potential-melastatin 8 (TRPM8) is a non-selective Ca²⁺-permeable channel, activated by cold, membrane depolarization, and different cooling compounds. TRPM8 expression has been found in gut mucosal, submucosal, and muscular nerve endings. Although TRPM8 plays a role in pathological conditions, being involved in visceral pain and inflammation, the physiological functions in the digestive system remain unclear as yet. The aims of the present study were: (i) to verify the TRPM8 expression in human distal colon; (ii) to examine the effects of TRPM8 activation on colonic contractility; (iii) to characterize the mechanism of action. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting were used to analyze TRPM8 expression. The responses of human colon circular strips to different TRPM8 agonists [1-[Dialkyl-phosphinoyl]-alkane (DAPA) 2–5, 1-[Diisopropyl-phosphinoyl]-alkane (DIPA) 1–7, DIPA 1–8, DIPA 1–9, DIPA 1–10, and DIPA 1–12) were recorded using a vertical organ bath. The biomolecular analysis revealed gene and protein expression of TRPM8 in both mucosal and smooth muscle layers. All the agonists tested, except-DIPA 1–12, produced a concentration-dependent decrease in spontaneous contraction amplitude. The effect was significantly antagonized by 5-benzyloxytryptamine, a TRPM8 antagonist. The DIPA 1–8 agonist resulted in the most efficacious and potent activation among the tested molecules. The DIPA 1–8 effects were not affected by tetrodotoxin, a neural blocker, but they were significantly reduced by tetraethylammonium chloride, a non-selective blocker of K⁺ channels. Moreover, iberiotoxin, a blocker of the large-conductance Ca²⁺-dependent K⁺-channels, but not apamin, a blocker of small-conductance Ca²⁺-dependent K⁺ channels, significantly reduced the inhibitory DIPA 1–8 actions. The results of the present study demonstrated that TRPM8 receptors are also expressed in human distal colon in healthy conditions and that ligand-dependent TRPM8 activation is able to reduce the colonic spontaneous motility, probably by the opening of the large-conductance Ca²⁺-dependent K⁺-channels.

Usefulness of Machine Learning-Based Gut Microbiome Analysis for Identifying Patients with Irritable Bowels Syndrome

Irritable bowel syndrome (IBS) is diagnosed by subjective clinical symptoms. We aimed to establish an objective IBS prediction model based on gut microbiome analyses employing machine learning. We collected fecal samples and clinical data from 85 adult patients who met the Rome III criteria for IBS, as well as from 26 healthy controls. The fecal gut microbiome profiles were analyzed by 16S ribosomal RNA sequencing, and the determination of short-chain fatty acids was performed by gas chromatography-mass spectrometry. The IBS prediction model based on gut microbiome data after machine learning was validated for its consistency for clinical diagnosis. The fecal microbiome alpha-diversity indices were significantly smaller in the IBS group than in the healthy controls. The amount of propionic acid and the difference between butyric acid and valerate were significantly higher in the IBS group than in the healthy controls (p < 0.05). Using LASSO logistic regression, we extracted a featured group of bacteria to distinguish IBS patients from healthy controls. Using the data for these featured bacteria, we established a prediction model for identifying IBS patients by machine learning (sensitivity >80%; specificity >90%). Gut microbiome analysis using machine learning is useful for identifying patients with IBS.

Clinical Response and Changes of Cytokines and Zonulin Levels in Patients with Diarrhoea-Predominant Irritable Bowel Syndrome Treated with Bifidobacterium Longum ES1 for 8 or 12 Weeks: A Preliminary Report

Bifidobacterium longum (B. longum) ES1 is a probiotic strain capable of modulating microbiome composition, anti-inflammatory activity and intestinal barrier function. We investigated the use of B. Longum ES1 in the treatment of patients with diarrhoea-predominant irritable bowel syndrome (IBS-D). Sixteen patients were treated for 8 or 12 weeks with B. Longum ES1 (1 × 10⁹ CFU/day). Serum zonulin and cytokines were measured at baseline (T0) and at the end of therapy (T1). Clinical response to therapy was assessed by IBS Severity Scoring System. Interleukin (IL)-6, IL-8, IL-12p70 and tumor necrosis factor (TNF) α levels decreased from T0 to T1, irrespective of treatment duration (p < 0.05), while zonulin levels diminished only in patients treated for 12 weeks (p = 0.036). Clinical response was observed in 5/16 patients (31%): 4/8 (50%) treated for 12 weeks and 1/8 (13%) treated for 8 weeks. Abdominal pain improved only in patients treated for 12 weeks (5/8 vs. 0/8, p = 0.025), while stool consistency improved regardless of therapy duration (p < 0.001). In conclusion, the results of this pilot study showed, in IBS-D patients treated for 12 weeks with B. longum ES1, a reduction in the levels of pro-inflammatory cytokines, and intestinal permeability as well as an improvement in gastrointestinal symptoms, but further studies including a placebo-control group are necessary to prove a causal link.

Randomised Controlled Trial: Partial Hydrolysation of Casein Protein in Milk Decreases Gastrointestinal Symptoms in Subjects with Functional Gastrointestinal Disorders

Unspecific gastrointestinal symptoms associated with milk consumption are common. In addition to lactose, also other components of milk may be involved. We studied whether the partial hydrolysation of milk proteins would affect gastrointestinal symptoms in subjects with functional gastrointestinal disorders. In a randomised, placebo-controlled crossover intervention, subjects (n = 41) were given ordinary or hydrolysed high-protein, lactose-free milkshakes (500 mL, 50 g protein) to be consumed daily for ten days. After a washout period of ten days, the other product was consumed for another ten days. Gastrointestinal symptoms were recorded daily during the study periods, and a validated irritable bowel syndrome-symptom severity scale (IBS-SSS) questionnaire was completed at the beginning of the study and at the end of both study periods. Blood and urine samples were analysed for markers of inflammation, intestinal permeability and immune activation. Both the IBS-SSS score (p = 0.001) and total symptom score reported daily (p = 0.002) were significantly reduced when participants consumed the hydrolysed product. Less bloating was reported during both study periods when compared with the baseline (p < 0.01 for both groups). Flatulence (p = 0.01) and heartburn (p = 0.03) decreased when consuming the hydrolysed product but not when drinking the control product. No significant differences in the levels of inflammatory markers (tumor necrosis factor alpha, TNF-α and interleukin 6, IL-6), intestinal permeability (fatty acid binding protein 2, FABP2) or immune activation (1-methylhistamine) were detected between the treatment periods. The results suggest that the partial hydrolysation of milk proteins (mainly casein) reduces subjective symptoms to some extent in subjects with functional gastrointestinal disorders. The mechanism remains to be resolved.

[Therapeutic management of irritable bowel syndrome in the family doctor's practice - probiotics and phytotherapeutics are often used successfully]

BACKGROUND

Irritable bowel syndrome (RDS) is one of the most common functional disorders of the gastrointestinal tract in primary care. As pathophysiology is still insufficiently understood and there is no causal therapeutic approach, therapy is still a challenge in daily practice.

METHOD

As part of a nationwide survey in written form, primary care physicians (general practitioners and internists) were contacted by postal service and asked to complete a questionnaire on RDS. The focus was on the therapeutic management of RDS patients and personal experience with the various drug therapy options.

RESULTS

A total of 487 doctors from all federal states participated in this survey. According to the doctors, more than 70% of RDS patients present with multiple symptoms and report a severe to very severe reduction in quality of life (78%). Doctors considered stress (76%), a change in the intestinal microbiome (56%), poor nutrition (35%) and visceral hypersensitivity (26%) to be the main causes of RDS. The drugs most commonly recommended by the specialist were antispasmodics (44%), phytotherapeutics (38%) and probiotics (37%). In contrast, only 54% of the GPs surveyed were satisfied with the success of spasmolytic therapy, but 75% were satisfied with phytotherapeutic agents and probiotics. More than 60% of the respondents were dissatisfied with tricyclic antidepressants. The high consultation intensity (72%) and expectations of the patients (73%) as well as their changing symptoms (49%) were identified by the doctors as the greatest challenges in daily practice.

CONCLUSION

Probiotics and phytotherapeutics are often a successful option for treating patients with irritable bowel syndrome in primary care.

Association Between Irritable Bowel Syndrome and Sleep Disturbance in Adolescents

Introduction

Sleep disorder in adolescents is a problem that is rarely considered by both parents and healthcare professionals. Ignorance of sleep disorders is likely caused by the very rare occurrence of associated sporadic or emergency cases. Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain and changes in the defecation pattern. Previous research has demonstrated IBS as one of the many causes of sleep disorders. Difficulty sleeping, frequent awakening, and difficulty returning to sleep after awakening are the symptoms often experienced by adolescents with IBS. The high incidence of IBS in adolescents and the large proportion of sleep disorders in IBS affect the quality of life and disrupt physical development, behaviour, and learning achievement. The relationship between IBS and sleep disorders in adolescents needs to be studied. This study aims to determine the relationship between sleep disorders and IBS in high school adolescents in Palembang.

Methods

This is a cross-sectional study conducted on 294 high school adolescents in Palembang in June 2018. Random sampling method was used and the presence of IBS and sleep disturbances were assessed using a questionnaire.

Results

Among all subjects, we found 113 subjects (38.4%) with IBS. Of these 113 subjects with IBS, only 60 subjects (53.1%) experienced sleep disorders.

Conclusion

No correlation found between sleep disorders and IBS in adolescents.

The relationship between dectin-1 and mast cells in patients with diarrhea-predominant irritable bowel syndrome

Background/Aims: Currently, the role of the microbiome GBA is being widely studied in the pathogenesis of visceral hypersensitivity in IBS. To investigate the role of fungus, the current study aimed to i) investigate the expression of Syk/CARD9-coupled Dectin-1 receptors in the ileocecal mucosa in D-IBS patients and (ii) explore the relationships between Dectin-1 and plasma MCT levels as well as anorectal sensory function in patients with D-IBS.Methods: Thirty-eight D-IBS patients who met the Rome III criteria and 2 groups of age- and sex-matched asymptomatic healthy controls were recruited from March 2015 to January 2017. Anorectal sensory function was quantified by HR-ARM. Plasma MCT titers were identified by ELISA, while the expression of Syk/CARD9 Dectin-1 receptors in ileocecal mucosa was identified by RT-qPCR.Results: (i) The expression of Syk/CARD9-coupled Dectin-1 receptors was significantly higher in D-IBS patients than in controls (p < .001). ii) The threshold values of first sensation and desire to defecate were significantly lower in D-IBS patientsthan in controls (the P value was0.007 and 0.001 respectively). (iii) There were negative correlations between plasma MCT levels and first sensation thresholds in D-IBS patients (r = -0.513, p = .012) and the desire to defecate thresholds (r = -0.423, p = .044). (iiii) There was a positive correlation between plasma MCT titers and the expression of Dectin-1 receptors in D-IBS patients (r = 0.565, p = .005).Conclusions: These results suggested that fungi may partially participate in the genesis of visceral hypersensitivity by activating mast cells, which is mediated by activation of the Dectin-1 receptor-mediated Syk/CARD9 signaling pathway.

Pomegranate Mesocarp against Colitis-Induced Visceral Pain in Rats: Effects of a Decoction and Its Fractions

The management of chronic visceral pain related to Inflammatory Bowel Diseases or Irritable Bowel Syndrome is still a clinical problem and new therapeutic strategies continue to be investigated. In the present study, the efficacy of a pomegranate decoction and of its polysaccharide and ellagitannin components in preventing the development of colitis-induced abdominal pain in rats was evaluated. After colitis induction by 2,4-dinitrobenzenesulfonic acid (DNBS), the pomegranate decoction (300 mg kg-1), polysaccharides (300 mg kg-1), and ellagitannins (45 mg kg-1) were orally administered for 14 days. Repeated treatment with decoction reduced visceral hypersensitivity in the colitic animals both at 7 and 14 days. Similar efficacy was shown by polysaccharides, but with lower potency. Ellagitannins administered at dose equivalent to decoction content showed higher efficacy in reducing the development of visceral pain. Macroscopic and microscopic evaluations performed on the colon 14 days after the damage showed that all three preparations reduced the overall amount of mast cells, the number of degranulated mast cells, and the density of collagen fibers in the mucosal stroma. Although ellagitannins seem to be responsible for most of the beneficial effects of pomegranate on DNBS-induced colitis, the polysaccharides support and enhance its effect. Therefore, pomegranate mesocarp preparations could represent a complementary approach to conventional therapies for promoting abdominal pain relief.

Risk of irritable bowel syndrome in patients who underwent appendectomy: A nationwide population-based cohort study

BACKGROUND

Appendectomy is one of the most common surgical procedures; however, the possible long-term consequences have not been fully explored. The appendix has been associated with microflora of the gut and immune functions. However, literature examining the relationship between prior appendectomy and the risk of irritable bowel syndrome (IBS) is lacking. The aim of this study was to evaluate the risk of irritable bowel syndrome for patients who underwent appendectomy by using a nationwide longitudinal population-based cohort.

METHODS

Data from this study was collected from Taiwan's National Health Insurance Research Database (NHIRD), a population-based database. We identified 12,760 patients who underwent appendectomy between January 1, 2000 and December 31, 2012. A total of 9236 patients who had appendectomy (case group) were randomly matched with 9236 patients who had not undergone appendectomy (control group) in a ratio of 1:1 by means of propensity scores. The hazard ratio (HR) of IBS was calculated by multiple Cox regression. Furthermore, sensitivity test and stratified analysis were performed.

FINDINGS

The incidence rate of IBS was 51.30 per 10,000 person-years in patients having appendectomy, more than the 35.28 per 10,000 person-years in patients not having appendectomy. Patients who underwent appendectomy had 1.46-fold risk of IBS compared to patients not having appendectomy (HR, 1.46; 95% CI, 1.24-1.72). Stratified analysis revealed that the higher HR of 1.55 (95% CI, 1.18-2.04) in patients <40 years old, and particularly within the first 5 years follow-up period of undergoing appendectomy. In addition, patients diagnosed with fibromyalgia had a greater risk of suffering IBS after appendectomy (HR, 1.41; 95% CI, 1.04-1.92).

INTERPRETATION

Patients with appendectomy have a higher incidental risk of IBS than the control population. The risk is higher for patients under 40 years old and those who received appendectomy within 5 years. Physicians could take this into consideration for treatment plans of patients who have underwent this surgery. Further research on the pathogenesis of this association is required.

FUNDING

This work was supported by grants from the Ministry of Health and Welfare, Taiwan (MOHW108-TDU-B-212-133004), China Medical University Hospital, Academia Sinica Stroke Biosignature Project (BM10701010021), MOST Clinical Trial Consortium for Stroke (MOST 108-2321-B-039-003-), Tseng-Lien Lin Foundation, Taichung, Taiwan, and Katsuzo and Kiyo Aoshima Memorial Funds, Japan.

Parasitic infections in irritable bowel syndrome patients: evidence to propose a possible link, based on a case-control study in the south of Iran

OBJECTIVES

The current study aimed to evaluate the prevalence of parasitic infections and their possible association with irritable bowel syndrome (IBS), through a case-control study. Stool samples were collected from patients with IBS and healthy subjects and were examined microscopically to detect intestinal parasites.

RESULTS

A total of 200 subjects were enrolled in the study including 100 patients with IBS and 100 healthy controls. The patients were selected based on the Rome III criteria. Of the 100 patients with IBS, 65 (65%) were female and 35 (35%) were male, with a mean age of 42.57 (± 4.07) years. Of these, 30 (30%) were infected with at least one intestinal parasite; the most common ones were Blastocystis hominis and Giardia lamblia. Of the control cases, 64 (64%) were female and 36 (36%) were male, with a mean age of 41.82 (± 11.75) years. Of these, 16 (16%) were infected with at least one intestinal parasite; the most common were B. hominis and Endolimax. There was a significant difference between the rate of parasitic infections between the patients with IBS and the control in particular, B. hominis and G. lamblia. The findings of the study support a possible link between parasitic infections and IBS.

Inhibition of Microglial Activation in the Amygdala Reverses Stress-Induced Abdominal Pain in the Male Rat

BACKGROUND & AIMS

Psychological stress is a trigger for the development of irritable bowel syndrome and associated symptoms including abdominal pain. Although irritable bowel syndrome patients show increased activation in the limbic brain, including the amygdala, the underlying molecular and cellular mechanisms regulating visceral nociception in the central nervous system are incompletely understood. In a rodent model of chronic stress, we explored the role of microglia in the central nucleus of the amygdala (CeA) in controlling visceral sensitivity. Microglia are activated by environmental challenges such as stress, and are able to modify neuronal activity via synaptic remodeling and inflammatory cytokine release. Inflammatory gene expression and microglial activity are regulated negatively by nuclear glucocorticoid receptors (GR), which are suppressed by the stress-activated pain mediator p38 mitogen-activated protein kinases (MAPK).

METHODS

Fisher-344 male rats were exposed to water avoidance stress (WAS) for 1 hour per day for 7 days. Microglia morphology and the expression of phospho-p38 MAPK and GR were analyzed via immunofluorescence. Microglia-mediated synaptic remodeling was investigated by quantifying the number of postsynaptic density protein 95-positive puncta. Cytokine expression levels in the CeA were assessed via quantitative polymerase chain reaction and a Luminex assay (Bio-Rad, Hercules, CA). Stereotaxic infusion into the CeA of minocycline to inhibit, or fractalkine to activate, microglia was followed by colonic sensitivity measurement via a visceromotor behavioral response to isobaric graded pressures of tonic colorectal distension.

RESULTS

WAS induced microglial deramification in the CeA. Moreover, WAS induced a 3-fold increase in the expression of phospho-p38 and decreased the ratio of nuclear GR in the microglia. The number of microglia-engulfed postsynaptic density protein 95-positive puncta in the CeA was increased 3-fold by WAS, while cytokine levels were unchanged. WAS-induced changes in microglial morphology, microglia-mediated synaptic engulfment in the CeA, and visceral hypersensitivity were reversed by minocycline whereas in stress-naïve rats, fractalkine induced microglial deramification and visceral hypersensitivity.

CONCLUSIONS

Our data show that chronic stress induces visceral hypersensitivity in male rats and is associated with microglial p38 MAPK activation, GR dysfunction, and neuronal remodeling in the CeA.

Impact of symptom severity in patients with diarrhoea-predominant irritable bowel syndrome (IBS-D): results from two separate surveys of HCPs and patients with IBS-D

BACKGROUND

Management of diarrhoea-predominant irritable bowel syndrome (IBS-D) is generally based on patient-reported symptoms; however, limited information on symptom severity exists. The objective of the study was to assess the impact of IBS-D severity on patient burden and patient and healthcare professional attitudes towards IBS.

METHODS

We conducted two web-based surveys of healthcare professionals and patients from Australia, Canada and Europe. We analysed patient characteristics and attitudes by IBS-D severity, which was assessed retrospectively using a composite of four variables: worst abdominal pain, IBS symptom frequency, Bristol Stool Form Scale and quality of life.

RESULTS

Of 679 healthcare professional respondents, one-third routinely classified patients by severity. The patient survey was completed by 513 patients with mild (26%), moderate (33%) and severe (41%) IBS-D, classified using the composite scale. Age, sex and treatment satisfaction did not change with severity; however, 19% of patients classified with severe IBS-D agreed with the statement: 'When my IBS is bad, I wish I was dead' versus 4 and 7% of patients with mild and moderate IBS-D, respectively (p < 0.05). Significantly more patients classified with severe IBS-D reported medication use versus mild IBS-D.

CONCLUSION

Compared with milder symptoms, severe IBS-D was associated with increased medication use and a negative perspective of IBS-D. This highlights the need for a validated severity scale to inform treatment decisions.

Efficacy of Lactobacillus paracasei HA-196 and Bifidobacterium longum R0175 in Alleviating Symptoms of Irritable Bowel Syndrome (IBS): A Randomized, Placebo-Controlled Study

Specific probiotic strains can alleviate the gastrointestinal (GI) symptoms and psychiatric comorbidities of irritable bowel syndrome (IBS). In this randomized, double-blind, placebo-controlled study, the efficacy of Lactobacillus paracasei HA-196 (L. paracasei) and Bifidobacterium longum R0175 (B. longum) in reducing the GI and psychological symptoms of IBS was evaluated in 251 adults with either constipation (IBS-C), diarrhea (IBS-D), or mixed-pattern (IBS-M). Following a 2-week run-in period, participants were randomized to one of three interventions: L. paracasei (n = 84), B. longum (n = 83) or placebo (n = 81). IBS symptoms, stool frequency and consistency and quality of life were assessed by questionnaires. The differences from baseline in the severity of IBS symptoms at 4 and 8 weeks were similar between groups. Participants in this study were classified, after randomization, into subtypes according to Rome III. Within the L. paracasei group, complete spontaneous and spontaneous bowel movement frequency increased in participants with IBS-C (n = 10) after 8 weeks of supplementation (both p < 0.05) and decreased in participants with IBS-D (n = 10, p = 0.013). Both L. paracasei and B. longum supplementation improved the quality of life in emotional well-being and social functioning compared with baseline (all p < 0.05). In conclusion, L. paracasei and B. longum may reduce GI symptom severity and improve the psychological well-being of individuals with certain IBS subtypes.

Volatomics in inflammatory bowel disease and irritable bowel syndrome

Volatile organic compounds (VOCs) are produced by the human metabolism, inflammation and gut microbiota and form the basis of innovative volatomics research. VOCs detected through breath and faecal analysis hence serve as attractive, non-invasive biomarkers for diagnosing and monitoring irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). This review describes the clinical applicability of volatomics in discriminating between IBS, IBD and healthy volunteers with acceptable accuracy in breath (70%-100%) and faecal (58%-85%) samples. Promising compounds are propan-1-ol for diagnosing and monitoring of IBD patients, and 1-methyl-4-propan-2-ylcyclohexa-1,4-diene as biomarker for IBS diagnosis. However, these VOCs often seem to be related to inflammation and probably will need to be used in conjunction with other clinical evidence. Furthermore, three interventional studies underlined the potential of VOCs in predicting treatment outcome and patient follow-up. This shows great promise for future use of VOCs as non-invasive breath and faecal biomarkers in personalised medicine. However, properly designed studies that correlate VOCs to IBD/IBS pathogenesis, while taking microbial influences into account, are still key before clinical implementation can be expected.

Potential neuro-immune therapeutic targets in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by recurring abdominal pain and disturbed bowel habits. The aetiology of IBS is unknown but there is evidence that genetic, environmental and immunological factors together contribute to the development of the disease. Current treatment of IBS includes lifestyle and dietary interventions, laxatives or antimotility drugs, probiotics, antispasmodics and antidepressant medication. The gut-brain axis comprises the central nervous system, the hypothalamic pituitary axis, the autonomic nervous system and the enteric nervous system. Within the intestinal mucosa there are close connections between immune cells and nerve fibres of the enteric nervous system, and signalling between, for example, mast cells and nerves has shown to be of great importance during GI disorders such as IBS. Communication between the gut and the brain is most importantly routed via the vagus nerve, where signals are transmitted by neuropeptides. It is evident that IBS is a disease of a gut-brain axis dysregulation, involving altered signalling between immune cells and neurotransmitters. In this review, we analyse the most novel and distinct neuro-immune interactions within the IBS mucosa in association with already existing and potential therapeutic targets.

Update on Eluxadoline for the Treatment of Irritable Bowel Syndrome with Diarrhea: Patient Selection and Perspectives

Irritable bowel syndrome (IBS) is a functional gastrointestinal (GI) disorder characterized by chronic abdominal pain associated with changes in bowel habits. It is the most common GI problem seen by gastroenterologists. IBS is a heterogenous disorder encompassing a spectrum of underlying mechanisms and clinical presentations. The pathophysiology of diarrhea-predominant form of IBS (IBS-D) remains poorly understood, and current available therapeutic options for IBS-D are limited. Eluxadoline is a novel, locally acting mixed μ- and κ-opioid receptor agonist and δ-receptor antagonist approved by the Food and Drug Administration (FDA) for treatment of adults with IBS-D. Data from two phase III clinical trials showed that approximately 25–30% of the eluxadoline-treated patients achieved composite clinical response, defined by a reduction of abdominal pain and improvement in stool consistency. Patients who achieve composite response during the first month of therapy were significantly more likely to demonstrate sustained clinical response. The most common adverse events reported with eluxadoline use were constipation, nausea and abdominal pain. The risk of abuse, dependence, or withdrawal is low. Serious adverse events associated with eluxadoline include sphincter of Oddi spasm (SOS) and pancreatitis particularly in patients without a gallbladder. Development of pancreatitis is likely secondary to SOS, but it remains unclear why pancreatitis occurs so quickly after initial doses. This adverse event profile helps guide proper selection of IBS-D patients for eluxadoline use, with important contraindications including absence of a gallbladder, biliary duct obstruction or sphincter of Oddi dysfunction, alcoholism, history of pancreatitis, or structural diseases of the pancreas. With the recent clinical trials demonstrating its efficacy, eluxadoline provides an additional option to the few existing pharmacologic interventions available for IBS-D. In this review, we discuss the drug development, efficacy and safety of eluxadoline, as well as selection criteria for identifying appropriate candidates for this medication.

Mucosal Microbiome Profiles Polygenic Irritable Bowel Syndrome in Mestizo Individuals

Irritable bowel syndrome (IBS) is the most frequent functional gastrointestinal disorder, worldwide, with a high prevalence among Mestizo Latin Americans. Because several inflammatory disorders appear to affect this population, a further understanding of host genomic background variants, in conjunction with colonic mucosa dysbiosis, is necessary to determine IBS physiopathology and the effects of environmental pressures. Using a simple polygenic model, host single nucleotide polymorphisms (SNPs) and the taxonomic compositions of microbiota were compared between IBS patients and healthy subjects. As proof of concept, five IBS-Rome III patients and five healthy controls (HCs) were systematically studied. The human and bacterial intestinal metagenome of each subject was taxonomically annotated and screened for previously annotated IBS, ulcerative colitis, and Crohn's disease-associated SNPs or taxon abundance. Dietary data and fecal markers were collected and associated with the intestinal microbiome. However, more than 1,000 variants were found, and at least 76 SNPs differentiated IBS patients from HCs, as did associations with 4 phyla and 10 bacterial genera. In this study, we found elements supporting a polygenic background, with frequent variants, among the Mestizo population, and the colonic mucosal enrichment of Bacteroides, Alteromonas, Neisseria, Streptococcus, and Microbacterium, may serve as a hallmark for IBS.

Gender of partner affects the interaction pattern during group creative idea generation

This study aimed to determine how gender composition affects the group creative process. Participants were recruited into dyads with different gender compositions (female-male dyad, F-M; female-female, F-F; male-male, and M-M) to solve two problems. One problem demanded creativity alternative use task (AUT) and the other did not object characteristic task. Functional near-infrared spectroscopy (fNIRS)-based hyperscanning was used to record interpersonal neural responses. Results demonstrated no significant difference in creative performance among the three types of dyads. However, the F-F dyad showed higher levels of cooperative behaviour (i.e. the index of convergence) and collective flexibility than the other dyads. Also, in the fNIRS data, the F-F dyad showed higher interpersonal brain synchronization (IBS) increments in the right posterior parietal cortex during the AUT than the other dyads, which covaried with their creative performance. These findings indicate that while solving a creativity problem together, females are more likely than males to consider others' perspectives. This gender difference might be due to the enhanced IBS increment in the right posterior parietal cortex.

Ephrin-B2 signaling in the spinal cord as a player in post-inflammatory and stress-induced visceral hypersensitivity

BACKGROUND

Ephrin-B2/EphB receptor signaling contributes to persistent pain states such as postinflammatory and neuropathic pain. Visceral hypersensitivity (VHS) is a major mechanism underlying abdominal pain in patients with irritable bowel syndrome (IBS) and inflammatory bowel diseases (IBD) in remission, but the underlying pathophysiology remains unclear. Here, we evaluated the spinal ephrin-B2/EphB pathway in VHS in 2 murine models of VHS, that is, postinflammatory TNBS colitis and maternal separation (MS).

METHODS

Wild-type (WT) mice and mice lacking ephrin-B2 in Na_v 1.8 nociceptive neurons (cKO) were studied. VHS was induced by: 1. intracolonic instillation of TNBS or 2. water avoidance stress (WAS) in mice that underwent maternal separation (MS). VHS was assessed by quantifying the visceromotor response (VMRs) during colorectal distention. Colonic tissue and spinal cord were collected for histology, gene, and protein expression evaluation.

KEY RESULTS

In WT mice, but not cKO mice, TNBS induced VHS at day 14 after instillation, which returned to baseline perception from day 28 onwards. In MS WT mice, WAS induced VHS for up to 4 weeks. In cKO however, visceral pain perception returned to basal level by week 4. The development of VHS in WT mice was associated with significant upregulation of spinal ephrin-B2 and EphB1 mRNA expression or protein levels in the TNBS model and upregulation of spinal ephrin-B2 protein in the MS model. No changes were observed in cKO mice. VHS was not associated with persistent intestinal inflammation.

CONCLUSIONS AND INFERENCES

Overall, our data indicate that the ephrin-B2/EphB1 spinal signaling pathway is involved in VHS and may represent a novel therapeutic target.

Plasma levels of guanylins are reduced in patients with Crohn's disease

Background: Guanylin (GN) and uroguanylin (UGN) are endogenous ligands for the intestinal receptor guanylate cyclase C (GC-C), an important regulator of intestinal fluid homeostasis. Gene expression and protein levels of GN are suppressed in inflamed intestinal tissue from patients with inflammatory bowel disease (IBD), but knowledge about plasma levels of guanylins in these conditions is sparse. We aimed to investigate the fasting plasma levels of the prohormones proGN and proUGN in patients with Crohn's Disease (CD) and relate these to levels found in persons with other diarrheal conditions, as well as persons with normal bowel habits.Methods: Plasma from patients with CD, patients with Familial GUCY2C Diarrheal Disease (FGDS), diarrhea-predominant irritable bowel syndrome (IBS-D) and healthy controls (HC) was analyzed using ELISA assays.Results: Significantly lower fasting plasma levels of proguanylins were found in CD and FGDS patients, compared to HC. In CD patients, plasma proGN levels correlated negatively with Harvey Bradshaw Index and with number of stools/24 h.Conclusion: Our data indicate that diarrhea may be a determinant for levels of proGN in plasma, and should be further explored in studies of different diarrheal disorders.