Lipid-induced colonic hypersensitivity in irritable bowel syndrome: the role of 5-HT3 receptors

Protective effect of Pediococcus pentosaceus Li05 on diarrhea-predominant irritable bowel syndrome in rats

Pediococcus pentosaceus Li05 (Li05) has demonstrated potential benefits in various intestinal and liver diseases, but its potential and mechanisms in relieving diarrhea have not been understood. The objective of this research was to examine the effects and mechanisms of Li05 in rats with diarrhea-predominant irritable bowel syndrome (IBS-D) induced by wrap restrain stress (WRS) and 4% acetic acid. The results demonstrated that Li05 effectively alleviated weight loss, visceral sensitivity and diarrhea in rats with IBS-D. It also improved intestinal and systemic inflammation by reducing the levels of chemokines and proinflammatory cytokines (GRO/KC, RANTES, IL-1β, IL-7, and IL-18). The 5-hydroxytryptamine (5-HT) signaling pathway is involved in regulating excessive intestinal motility and secretion in IBS-D. Li05 effectively reduced the expression levels of the 5-HT3B receptor (5-HT3BR) (p < 0.01) in the intestine. Additionally, Li05 intervention had a regulatory effect on the gut composition, with a decrease in the abundance of [Ruminococcus] gauvreauii group, Dubosiella, Erysipelatoclostridium and Blautia, and an increase in the abundance of Alloprevotella, Anaerotruncus and Mucispirillum. Furthermore, Li05 induced significant changes in fatty acid and amino acid metabolism in the gut of rats with IBS-D. These findings indicate that Li05 exhibits an effective improvement in IBS-D symptoms by reducing inflammation and modulating gut microbiota and metabolism. Based on the above results, Li05 holds promise as a potential probiotic for managing IBS-D.

Food intolerance related to gastrointestinal symptoms amongst adults living with bile acid diarrhoea: A cross-sectional study

BACKGROUND

The role of food in managing bile acid diarrhoea (BAD) is poorly understood. The present study explored the prevalence of food intolerance amongst adults with BAD.

METHODS

The study comprised a cross-sectional survey of adults with BAD determined by the 75 selenium homotaurocholic acid test (SeHCAT) living in the UK. Participants anonymously completed an online questionnaire on 39 food items. Frequency of food in general affecting BAD symptoms, as well as frequencies of diarrhoea, abdominal pain, bloating, flatulence and consequential food avoidance after food item ingestion, were assessed. Food group avoidance was also assessed.

RESULTS

There were 434 participants who completed the questionnaire between April and May 2021 of whom 80% reported moderate to severe chronic diarrhoea. Food intolerances were reported by 88.0% (95% confidence interval [CI] = 84.6-90.9) of participants. Diarrhoea was reported most frequently after take-away food, fish and chips, creamy sauces, cream and large quantities of fruit (range 41.0%-33.6%). Lowest frequencies were for potato, avocado, mango, watermelon and pear (range 3.7%-7.4%) for the foods listed in the questionnaire. Similar trends were found for abdominal pain, bloating, flatulence and consequential food avoidance. Symptom-triggering within 30 min of ingestion was more prevalence than after 30 min for almost all foods. Food group avoidance was highest for fatty foods (81.2%; 95% CI = 77.8-85.3) followed by dairy (53.9%; 95% CI = 49.1-58.7).

CONCLUSIONS

Perceived food intolerance amongst adults with BAD and persisting diarrhoeal symptoms is high. Important triggers were meals with a higher fat content and higher-fat dairy products. Diets amongst those with persisting diarrhoeal symptoms may be overly restrictive.

Intestinal chemosensitivity in irritable bowel syndrome associates with small intestinal TRPV channel expression

BACKGROUND

Irritable bowel syndrome (IBS) patients often experience meal-associated symptoms. However, the underlying mechanisms are unclear.

AIM

To determine small intestinal mechanisms of lipid-induced symptoms and rectal hypersensitivity in IBS METHODS: We recruited 26 IBS patients (12 IBS-C, 14 IBS-D) and 15 healthy volunteers (HV). In vivo permeability was assessed using saccharide excretion assay. Rectal sensitivity was assessed using a barostat before and after small bowel lipid infusion; symptoms were assessed throughout. Next, an extended upper endoscopy with probe-based confocal laser endomicroscopy (pCLE) was performed with changes induced by lipids. Duodenal and jejunal mucosal biopsies were obtained for transcriptomics.

RESULTS

Following lipid infusion, a higher proportion of HV than IBS patients reported no pain, no nausea, no fullness and no urgency (P < 0.05 for all). In a model adjusted for sex and anxiety, IBS-C and IBS-D patients had lower thresholds for first rectal sensation (P = 0.0007) and pain (P = 0.004) than HV. In vivo small intestinal permeability and mean pCLE scores were similar between IBS patients and HV. Post-lipid, pCLE scores were higher than pre-lipid but were not different between groups. Baseline duodenal transient receptor potential vanilloid (TRPV) 1 and 3 expression was increased in IBS-D, and TRPV3 in IBS-C. Duodenal TRPV1 expression correlated with abdominal pain (r = 0.51, FDR = 0.01), and inversely with first rectal sensation (r = -0.48, FDR = 0.01) and pain (r = -0.41, FDR = 0.02) thresholds.

CONCLUSION

Lipid infusion elicits a greater symptom response in IBS patients than HV, which is associated with small intestinal expression of TRPV channels. TRPV-mediated small intestinal chemosensitivity may mediate post-meal symptoms in IBS.

Sacral Nerve Modulation Has No Effect on the Postprandial Response in Irritable Bowel Syndrome

Purpose

Irritable bowel syndrome is a common gastrointestinal disorder with a global prevalence of approximately 11%. Onset or worsening of symptoms following digestion is one of the characteristics of the condition. The present study aimed at evaluating the postprandial sensory and motor response before and after treatment with sacral nerve modulation.

Patients and Methods

Twenty-one irritable bowel syndrome patients, 12 diarrhea-predominant and 9 mixed, were eligible for a 6-week sacral nerve modulation test period. Patients were investigated with multimodal impedance planimetry including a standardized meal at baseline and at the end of 2 weeks of suprasensory stimulation embedded in the 6-week sacral nerve modulation period.

Results

There was no statistical significant difference in the sensory response to heat or cold before and after sacral nerve modulation, p>0.05. At baseline, wall tension increased after the meal (mean 124.79 [range 82.5 to 237.3] mmHg.mm before the meal, mean 207.76 [range, 143.5 to 429] mmHg.mm after the meal), p=0.048 indicating a postprandial response. During sacral nerve modulation, the postprandial increase in wall tension did not reach statistical significance (mean 86.79 [range 28.8 to 204.5] mmHg.mm before the meal, mean 159.71 [range 71.3 to 270.8] mmHg.mm after the meal), p=0.277. However, there was no statistically significant difference between the postprandial wall tension at baseline and during sacral nerve modulation, p=0.489. Likewise, we found no difference between pressure or stretch ratio at baseline and during sacral nerve modulation, p>0.05.

Conclusion

Sacral nerve modulation does not exert its positive treatments effects in diarrhea-predominant and mixed irritable bowel syndrome through a modulation of the postprandial response.

Irritable bowel syndrome and food interaction

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders in Western countries. Despite the high prevalence of this disorders, the therapeutic management of these patients is often unsatisfactory. A number of factors have been suggested to be involved in the pathogenesis of IBS, including impaired motility and sensitivity, increased permeability, changes in the gut microbiome and alterations in the brain-gut axis. Also food seems to play a critical role: the most of IBS patients report the onset or the exacerbation of their symptoms after the meals. Recently, an increasing attention has been paid to the role of food in IBS. In this review we summarize the most recent evidences about the role of diet on IBS symptoms. A diet restricted in fermentable, poorly absorbed carbohydrates and sugar alcohols has beneficial effects on IBS symptoms. More studies are needed to improve our knowledge about the relationship between food and IBS. However, in the foreseeable future, dietary strategies will represent one of the key tools in the therapeutic management of patients with IBS.

Irritable bowel syndrome: methods, mechanisms, and pathophysiology. Methods to assess visceral hypersensitivity in irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, characterized by recurrent abdominal pain or discomfort in combination with disturbed bowel habits in the absence of identifiable organic cause. Visceral hypersensitivity has emerged as a key hypothesis in explaining the painful symptoms in IBS and has been proposed as a "biological hallmark" for the condition. Current techniques of assessing visceral perception include the computerized barostat using rectal distensions, registering responses induced by sensory stimuli including the flexor reflex and cerebral evoked potentials, as well as brain imaging modalities such as functional magnetic resonance imaging and positron emission tomography. These methods have provided further insight into alterations in pain processing in IBS, although the most optimal method and condition remain to be established. In an attempt to give an overview of these methods, a literature search in the electronic databases PubMed and MEDLINE was executed using the search terms "assessment of visceral pain/visceral nociception/visceral hypersensitivity" and "irritable bowel syndrome." Both original articles and review articles were considered for data extraction. This review aims to discuss currently used modalities in assessing visceral perception, along with advantages and limitations, and aims also to define future directions for methodological aspects in visceral pain research. Although novel paradigms such as brain imaging and neurophysiological recordings have been introduced in the study of visceral pain, confirmative studies are warranted to establish their robustness and clinical relevance. Therefore, subjective verbal reporting following rectal distension currently remains the best-validated technique in assessing visceral perception in IBS.

First evidence for an association of a functional variant in the microRNA-510 target site of the serotonin receptor-type 3E gene with diarrhea predominant irritable bowel syndrome

Diarrhea predominant irritable bowel syndrome (IBS-D) is a complex disorder related to dysfunctions in the serotonergic system. As cis-regulatory variants can play a role in the etiology of complex conditions, we investigated the untranslated regions (UTRs) of the serotonin receptor type 3 subunit genes HTR3A and HTR3E. Mutation analysis was carried out in a pilot sample of 200 IBS patients and 100 healthy controls from the UK. The novel HTR3E 3'-UTR variant c.*76G>A (rs62625044) was associated with female IBS-D (P = 0.033, OR = 8.53). This association was confirmed in a replication study, including 119 IBS-D patients and 195 controls from Germany (P = 0.0046, OR = 4.92). Pooled analysis resulted in a highly significant association of c.*76G>A with female IBS-D (P = 0.0002, OR = 5.39). In a reporter assay, c.*76G>A affected binding of miR-510 to the HTR3E 3'-UTR and caused elevated luciferase expression. HTR3E and miR-510 co-localize in enterocytes of the gut epithelium as shown by in situ hybridization and RT-PCR. This is the first example indicating micro RNA-related expression regulation of a serotonin receptor gene with a cis-regulatory variant affecting this regulation and appearing to be associated with female IBS-D.

New insights into the pathogenesis and pathophysiology of irritable bowel syndrome

The pathogenesis and pathophysiology of irritable bowel syndrome is complex and still incompletely known. Potential pathogenetic factors include genes, infectious events, psychological symptoms and other loosely defined environmental factors. Both alterations at the central and peripheral level are thought to contribute to the symptoms of irritable bowel syndrome, including psychosocial factors, abnormal gastrointestinal motility and secretion, and visceral hypersensitivity. Today irritable bowel syndrome is viewed upon as a disorder of dysregulation of the so-called brain-gut axis, involving abnormal function in the enteric, autonomic and/or central nervous systems, with peripheral abnormalities probably dominating in some patients and disturbed central processing of signals from the periphery in others. Lines of evidence also suggest that inflammation within the gastrointestinal tract may be of great importance in at least subgroups of irritable bowel syndrome patients. To conclude, a complex picture of the pathogenesis and pathophysiology of irritable bowel syndrome is emerging, with interactions between several different alterations resulting in the divergent symptom pattern in these patients.

Lipid-induced colonic hypersensitivity in the irritable bowel syndrome: the role of bowel habit, sex, and psychologic factors

BACKGROUND & AIMS

Duodenal lipid infusion increases colonic hypersensitivity in irritable bowel syndrome (IBS). Whether this is affected by bowel habit, psychologic factors, or sex is unknown.

METHODS

We included 61 patients with IBS (50 women, 11 men), 25 with diarrhea-predominant IBS, 17 with constipation-predominant IBS, 19 with alternating-type IBS, and 20 healthy controls (15 women, 5 men). A colonic distension trial was performed with a barostat before and after a 1-hour duodenal lipid infusion (3 kcal/min). Colonic thresholds, colonic tone, and the viscerosomatic referral pattern were assessed and compared between groups. Patients also completed the Hospital Anxiety and Depression scale.

RESULTS

The reduction in colonic pressure thresholds after vs before duodenal lipids was greater in patients than in controls for discomfort (P = .006) and pain (P < .0001). An increased viscerosomatic referral area for pain and discomfort during colonic distensions after vs before duodenal lipids was observed in patients but not in controls. The response was similar in IBS subgroups based on the predominant bowel habit, in patients with vs without anxiety and/or depression, and in women and men with IBS. The colonic tone response during lipid infusion was similar in IBS patients and controls, and in the different IBS subgroups.

CONCLUSIONS

IBS patients show increased colonic sensitivity and altered viscerosomatic referral pattern after duodenal lipids. This response is largely unaffected by the predominant bowel habit, psychologic factors, or sex, but seems to be related to IBS per se.

Nutrient-dependent enhancement of rectal sensitivity in irritable bowel syndrome (IBS)

Food-related gastrointestinal symptoms are common in irritable bowel syndrome (IBS), but the mechanisms behind this are unclear. Enhanced colorectal sensitivity after duodenal lipid administration in IBS patients has been demonstrated. However, the effects of a regular meal on colorectal sensitivity in these patients and the importance of the composition of the meal are not known. On two separate days, 10 IBS patients and 11 controls randomly received a liquid meal (800 kcal), containing 60% calories from fat (fatty meal) or carbohydrate (carbohydrate meal). Using a barostat rectal sensitivity was assessed during four separate distension sequences before, immediately after and 30 and 60 min after the meal. In the patients, the discomfort (P = 0.04) and the pain thresholds (P = 0.007) were gradually reduced after the fatty meal, whereas only a tendency in the same direction was seen after the carbohydrate meal. In patients VAS ratings for pain increased after the fatty meal (P = 0.03), but not after carbohydrates. In the controls, sensory thresholds were not affected by the meals. In IBS, a liquid meal enhances rectal sensitivity, and this seems to be partly nutrient dependent as a fatty meal has more pronounced effects than a carbohydrate meal. This might be of relevance for their postprandial symptoms.

Serotonergic and non-serotonergic targets in the pharmacotherapy of visceral hypersensitivity

Visceral hypersensitivity is considered a key mechanism in the pathogenesis of functional gastrointestinal (GI) disorders. Targeting visceral hypersensitivity seems an attractive approach to the development of drugs for functional GI disorders. This review summarizes current knowledge on targets for the treatment of visceral hypersensitivity, and the status of current and future drug and probiotic treatment development, and the role of pharmacogenomic factors.

The serotonin signaling system: from basic understanding to drug development for functional GI disorders

Serotonin is an important gastrointestinal signaling molecule. It is a paracrine messenger utilized by enterochromaffin (EC) cells, which function as sensory transducers. Serotonin activates intrinsic and extrinsic primary afferent neurons to, respectively, initiate peristaltic and secretory reflexes and to transmit information to the central nervous system. Serotonin is also a neurotransmitter utilized by a system of long descending myenteric interneurons. Serotonin is synthesized through the actions of 2 different tryptophan hydroxylases, TpH1 and TpH2, which are found, respectively, in EC cells and neurons. Serotonin is inactivated by the serotonin reuptake transporter (SERT)-mediated uptake into enterocytes or neurons. The presence of many serotonin receptor subtypes enables selective drugs to be designed to therapeutically modulate gastrointestinal motility, secretion, and sensation. Current examples include tegaserod, a 5-HT(4) partial agonist, which has been approved for treatment of irritable bowel syndrome (IBS) with constipation in women and for chronic constipation in men and women. The 5-HT(3) antagonists, granisetron and ondansetron, are useful in combating the nausea associated with cancer chemotherapy, and alosetron is employed in the treatment of IBS with diarrhea. Serotonergic signaling abnormalities have also been putatively implicated in the pathogenesis of functional bowel diseases. Other compounds, for which efficacy has not been rigorously established, but which may have value, include tricyclic antidepressants and serotonin selective reuptake inhibitors to combat IBS, and 5-HT(1) agonists, which enhance gastric accommodation, to treat functional dyspepsia. The initial success encountered with serotonergic agents holds promise for newer and more potent insights and therapies of brain-gut disorders.

Hypnosis for irritable bowel syndrome: the quest for the mechanism of action

Irritable bowel syndrome (IBS) is a very common condition in the Western part of the world, and it accounts for a large proportion of the workload of a gastroenterologist. Unfortunately, the pathogenesis and pathophysiology of the syndrome are incompletely understood, and the treatment options are limited. However, hypnotherapy is one treatment option that has proven to be very useful in IBS. The mechanisms of action explaining why hypnosis is effective for IBS are not altogether known, but recent studies have shed some light on this issue. These studies, and what can be learned from them about how hypnosis impacts IBS, are reviewed in this article. Hypnosis may affect IBS partly through changes in colorectal sensitivity and improvement in psychological factors. The effects on GI motility and the autonomic nervous system are less clear and need further evaluation.

Food hypersensitivity-immunologic (peripheral) or cognitive (central) sensitisation?

Patients with food hypersensitivity suffer poor quality of life and several unexplained health complaints, both abdominal and extra-abdominal. Part of the suffering is due to healthcare providers' neglect and poor insight, allowing a strong position for alternative medicine. Distinguishing food allergy from functional and organic disorders can be extremely difficult. We have found examination of faecal calprotectin and gut permeability to be useful for excluding organic disease, whilst conventional provocation tests for positive diagnosis of food hypersensitivity are cumbersome. Our new ultrasound provocation test has been promising, but we acknowledge that much work remains to be done before its sensitivity and specificity can be finally established. The majority of patients with self-reported food hypersensitivity have a non-allergic hypersensitivity disorder. We suggest that cognitive-emotional sensitisation at the brain level, and not peripheral (immunological) sensitisation, is a major pathogenetic mechanism by which the patients' various abdominal and extra-abdominal health complaints are generated. Extensive activation of cognitive networks might be triggered by peripheral sensory mechanisms, often misinterpreted as 'food allergy'. Clearly, the approach to patients with food hypersensitivity should be interdisciplinary.

Review article: drugs interfering with visceral sensitivity for the treatment of functional gastrointestinal disorders--the clinical evidence

At present, the concept of visceral hypersensitivity provides the leading hypothesis regarding the generation of symptoms in functional gastrointestinal disorders. This paper discusses the current clinical evidence for drugs that have been proposed to interfere with visceral sensitivity in functional gastrointestinal disorders. Several possible pharmacological targets have been identified to reduce visceral pain and to reverse the processes underlying the persistence of visceral hypersensitivity. However, most of the available evidence comes from experimental animal models and cannot simply be extrapolated to patients with functional gastrointestinal disorders. In this review, we selected five drug classes that have been shown to exhibit visceral analgesic properties in experimental studies, and of which data were available regarding their clinical efficacy. These included opioid substances, serotonergic agents, antidepressants, somatostatin analogues and alpha(2)-adrenergic agonists. Although clinical trials show a limited benefit, in particular for serotonergic agents, the evidence illustrating that these effects result from normalization of visceral sensation is currently lacking. Therefore, we conclude that the concept of targeting visceral hypersensitivity as a treatment for functional gastrointestinal disorders is still controversial. Future evaluations require patient selection based on the presence of visceral hypersensitivity and application of compounds that exhibit 'true' viscerosensory effects.

Association of upper and lower gastrointestinal tract symptoms with body mass index in an Australian cohort

Food modulates gastrointestinal (GI) function and GI symptoms could alter food intake, but it is not established whether or not obese people experience more or less GI symptoms. We aimed at evaluating the association between body mass index (BMI) and specific GI symptoms in the community. Population-based random samples from Sydney, Australia (n = 777) completed a validated questionnaire. The association of each GI symptom with BMI (kg m(-2)) categories was assessed using logistic regression analysis adjusting for potential confounders. The prevalence of obesity (BMI > or =30 kg m(-2)) was 22%. There were univariate associations (adjusting for age, sex, education level, alcohol and smoking) between increased BMI category and heartburn (OR = 1.9, 95% CI 1.4, 2.5), acid regurgitation (OR = 2.1, 95% CI 1.4, 2.9), increased bloating (OR = 1.3, 95%CI 1.1, 1.6), increased stool frequency (OR = 1.4, 95% CI 1.1, 1.7), loose and watery stools (OR = 1.5, 95% CI 1.1, 2.0) and upper abdominal pain (OR = 1.3, 95% CI 1.03, 1.6). Early satiety was associated with a lower BMI category but this was not significant after adjustment (OR = 0.8, 95% CI 0.6, 1.1). Lower abdominal pain, postprandial fullness, nausea and vomiting were not associated with BMI category. In a regression model adjusting for sex, education, smoking, alcohol and all GI symptoms, older age, less early satiety and increased stool frequency and heartburn were all independently associated with increasing BMI (all P < 0.01). Heartburn and diarrhoea were associated with increased BMI, while early satiety was associated with a lower BMI in this population.

Oxytocin stimulates colonic motor activity in healthy women

The effects of oxytocin in the gastrointestinal tract are unclear. The aim of this study was to examine the effect of infusion of oxytocin on colonic motility and sensitivity in healthy women. Fourteen healthy women were investigated twice. A 6-channel perfusion catheter, with three recording points (2 cm apart) proximally and three recording points distally to a barostat balloon, was inserted to the splenic flexure. An intestinal feeding tube was placed in the mid-duodenum. A 90-min duodenal lipid infusion of 3 kcal min(-1) was administered. Thirty minutes after the start of the lipid infusion, the subject randomly received either 20 or 40 mU min(-1) of oxytocin, or isotonic saline as intravenous infusions for 90 min. Meanwhile, the colonic motility was recorded. During the last 30 min of oxytocin and saline infusion, the visceral sensitivity to balloon distensions was examined. During lipid infusion the number of antegrade contractions per hour was 0.7 +/- 0.3 after saline and 3.9 +/- 1.4 after oxytocin (P = 0.03), indicating more pronounced lumen-occlusive contractile activity after oxytocin administration. Some of these consisted of high-amplitude (> 103 mmHg in amplitude) antegrade contractions. Lipid infusion evoked a decrease of the balloon volume, reflecting increased colonic tone, but there was no difference between saline and oxytocin. Sensory thresholds did not differ significantly between saline and oxytocin. Infusion of oxytocin stimulates antegrade peristaltic contractions in stimulated colon in healthy women. The effects of oxytocin on colonic motor activity deserve to be further explored, especially in patients with colonic peristaltic dysfunction.

Treatment with hypnotherapy reduces the sensory and motor component of the gastrocolonic response in irritable bowel syndrome

OBJECTIVE

Postprandial symptoms in irritable bowel syndrome are common and relate to an exaggerated motor and sensory component of the gastrocolonic response. We investigated whether this response can be affected by hypnotherapy.

METHODS

We included 28 patients with irritable bowel syndrome refractory to other treatments. They were randomized to receive gut-directed hypnotherapy 1 hour per week for 12 weeks (N = 14) or were provided with supportive therapy (control group; N = 14). Before randomization and after 3 months, all patients underwent a colonic distension trial before and after a 1-hour duodenal lipid infusion. Colonic sensory thresholds and tonic and phasic motor activity were assessed.

RESULTS

Before randomization, reduced thresholds after vs. before lipid infusion were seen in both groups for all studied sensations. At 3 months, the colonic sensitivity before duodenal lipids did not differ between groups. Controls reduced their thresholds after duodenal lipids for gas (22 +/- 1.7 mm Hg vs. 16 +/- 1.6 mm Hg, p <.01), discomfort (29 +/- 2.9 mm Hg vs. 22 +/- 2.6 mm Hg, p <.01), and pain (33 +/- 2.7 mm Hg vs. 26 +/- 3.3 mm Hg, p <.01), whereas the hypnotherapy group reduced their thresholds after lipids only for pain (35 +/- 4.0 mm Hg vs. 29 +/- 4.7 mm Hg, p <.01). The colonic balloon volumes and tone response at randomization were similar in both groups. At 3 months, baseline balloon volumes were lower in the hypnotherapy group than in controls (83 +/- 14 ml vs. 141 +/- 15 ml, p <.01). In the control group, reduced balloon volumes during lipid infusion were seen (141 +/- 15 ml vs. 111 +/- 19 ml, p <.05), but not after hypnotherapy (83 +/- 14 ml vs. 80 +/- 16 ml, p >.20).

CONCLUSION

Hypnotherapy reduces the sensory and motor component of the gastrocolonic response in patients with irritable bowel syndrome. These effects may be involved in the clinical efficacy of hypnotherapy in IBS.