The functional-organic dichotomy: postinfectious irritable bowel syndrome and inflammatory bowel disease-irritable bowel syndrome

Immune cell signatures and causal association with irritable bowel syndrome: A mendelian randomization study

BACKGROUND

The mucosal barrier's immune-brain interactions, pivotal for neural development and function, are increasingly recognized for their potential causal and therapeutic relevance to irritable bowel syndrome (IBS). Prior studies linking immune inflammation with IBS have been inconsistent. To further elucidate this relationship, we conducted a Mendelian randomization (MR) analysis of 731 immune cell markers to dissect the influence of various immune phenotypes on IBS. Our goal was to deepen our understanding of the disrupted brain-gut axis in IBS and to identify novel therapeutic targets.

AIM

To leverage publicly available data to perform MR analysis on 731 immune cell markers and explore their impact on IBS. We aimed to uncover immunophenotypic associations with IBS that could inform future drug development and therapeutic strategies.

METHODS

We performed a comprehensive two-sample MR analysis to evaluate the causal relationship between immune cell markers and IBS. By utilizing genetic data from public databases, we examined the causal associations between 731 immune cell markers, encompassing median fluorescence intensity, relative cell abundance, absolute cell count, and morphological parameters, with IBS susceptibility. Sensitivity analyses were conducted to validate our findings and address potential heterogeneity and pleiotropy.

RESULTS

Bidirectional false discovery rate correction indicated no significant influence of IBS on immunophenotypes. However, our analysis revealed a causal impact of IBS on 30 out of 731 immune phenotypes (P < 0.05). Nine immune phenotypes demonstrated a protective effect against IBS [inverse variance weighting (IVW) < 0.05, odd ratio (OR) < 1], while 21 others were associated with an increased risk of IBS onset (IVW ≥ 0.05, OR ≥ 1).

CONCLUSION

Our findings underscore a substantial genetic correlation between immune cell phenotypes and IBS, providing valuable insights into the pathophysiology of the condition. These results pave the way for the development of more precise biomarkers and targeted therapies for IBS. Furthermore, this research enriches our comprehension of immune cell roles in IBS pathogenesis, offering a foundation for more effective, personalized treatment approaches. These advancements hold promise for improving IBS patient quality of life and reducing the disease burden on individuals and their families.

'Symptom-free' when inflammatory bowel disease is in remission: Expectations raised by online resources

OBJECTIVES

Up to 60% of patients with inflammatory bowel disease (IBD) experience symptoms when in remission. Qualitative research suggests patients seldom feel they receive adequate explanations for these. This study explores how, and how often, ongoing symptoms during remission are represented on readily searchable patient websites.

METHODS

Bing, Google, and Yahoo were searched for websites providing medical information about IBD. Thematic analysis was used to inductively explore themes around symptoms during quiescent IBD, followed by deductive content analysis to quantify core themes.

RESULTS

Results indicated that remission is commonly defined as "few or no symptoms" and that there is limited information available on symptoms during remission. 55.6% of IBD websites provided a definition of remission based on symptom control only, while 44.4% also incorporated inflammatory control. The few websites that mentioned that symptoms may continue during remission (21.7%) related these to IBS.

CONCLUSIONS

Current website information is predominantly biomedical and fails to adequately explain how symptoms may persist during remission and how IBS and IBD may be linked.

PRACTICE IMPLICATIONS

Lack of explanatory models of symptoms in remission may lead to distress and increase anxiety about symptoms. Clearer explanations of these symptoms are needed.

Normal or diseased? Navigating indeterminate gut behaviour

Introduction Delayed diagnosis of gut disease is a continuing problem, variously attributed to a range of patient, doctor, and health system factors. Gut disease often begins with indeterminate gut behaviours that are hard to classify. Aim This study aimed to investigate delayed diagnosis from the point of view of the patient, or prospective patient. How gut and gut disease was understood, what might prompt them to seek care, and their experiences of seeking care. Methods Using a qualitative design, we interviewed 44 people in New Zealand. Thirty-three had a diagnosis of gut disease, and 11 did not, though some of the patients in this latter group had symptoms. Results Some participants had a smooth trajectory from first noticing gut symptoms to diagnosis. However, a subgroup of 22 participants experienced long periods of troublesome gut behaviours without a diagnosis. For this subgroup of 22 participants, we found people struggled to work out what was normal, thus influencing when they sought health care. Once they sought health care, experiences of that care could be frustrating, and achieving a diagnosis protracted. Some who remained undiagnosed felt abandoned, though had developed strategies to self-manage. Discussion Indeterminate gut behaviours remain complex to deal with and it can difficult for both patients and doctors to assess when a symptom or group of symptoms need further investigation, watchful waiting or the use of other supportive strategies. Effectively communicating with healthcare staff can be a significant problem and there is currently a gap in support for patients in this regard.

Irritable bowel syndrome and mental health comorbidity - approach to multidisciplinary management

Irritable bowel syndrome (IBS) affects 5-10% of the global population. Up to one-third of people with IBS also experience anxiety or depression. Gastrointestinal and psychological symptoms both drive health-care use in people with IBS, but psychological comorbidity seems to be more important for long-term quality of life. An integrated care approach that addresses gastrointestinal symptoms with nutrition and brain-gut behaviour therapies is considered the gold standard. However, best practice for the treatment of individuals with IBS who have a comorbid psychological condition is unclear. Given the rising prevalence of mental health disorders, discussion of the challenges of implementing therapy for people with IBS and anxiety and depression is critical. In this Review, we draw upon our expertise in gastroenterology, nutrition science and psychology to highlight common challenges that arise when managing patients with IBS and co-occurring anxiety and depression, and provide recommendations for tailoring clinical assessment and treatment. We provide best practice recommendations, including dietary and behavioural interventions that could be applied by non-specialists and clinicians working outside an integrated care model.

Diagnostic Implications of Irritable Bowel Syndrome Is an Independent Risk Factor for Undergoing Surgical Interventions in Patients with Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) can present with overlapping symptoms, making diagnosis and management challenging. Patients with IBD in remission may continue to experience IBS symptoms. Patients with IBS were found to have a disproportionately higher prevalence of abdominal and pelvic surgeries than the general population.

AIMS

The aim of this study was to determine whether IBS is a risk factor for undergoing surgical interventions in patients with IBD and explore the diagnostic implications of these findings.

METHODS

A population-based cohort analysis was performed using TriNetX. Patients with Crohn's disease + IBS (CD + IBS) and ulcerative colitis + IBS (UC + IBS) were identified. The control groups consisted of patients with CD or UC alone without IBS. The main outcome was to compare the risks of undergoing surgical interventions between the cohorts. The secondary outcomes were to compare the risks of developing gastrointestinal symptoms and IBD-related complications between the cohorts.

RESULTS

Patients with IBD who subsequently developed IBS were more likely to experience gastrointestinal symptoms than those without IBS (p < 0.0001). Patients with concomitant IBD and IBS were more likely to develop IBD-related complications, including perforation of the intestine, gastrointestinal bleeding, colon cancer, and abdominal abscess (p < 0.05). Patients with concomitant IBD and IBS were more likely to undergo surgical interventions than patients without IBS, including colectomy, appendectomy, cholecystectomy, exploratory laparotomy, and hysterectomy (p < 0.05).

CONCLUSIONS

IBS appears to be an independent risk factor for patients with IBD to develop IBD-related complications and undergo surgical interventions. Patients with concomitant IBD and IBS could represent a unique subgroup of IBD patients with more severe symptoms, highlighting the importance of accurate diagnosis and management in this population.

A Novel Digital Self-management Intervention for Symptoms of Fatigue, Pain, and Urgency in Inflammatory Bowel Disease: Describing the Process of Development

Background

Empirical studies and systematic reviews have demonstrated the role of biological, cognitive, behavioral, and emotional factors in fatigue, pain, and urgency in inflammatory bowel disease (IBD). Behavioral management that addresses the cognitive, behavioral, and emotional factors offered alongside medical treatment is seldom available to people with IBD. Digital interventions provide a potentially scalable and cost-effective way of providing behavioral support to patients.

Objective

This paper aimed to describe the process of developing a supported digital self-management intervention for fatigue, pain, and urgency in IBD using theory and evidence-based approaches and stakeholder input.

Methods

The Medical Research Council framework for complex health interventions and a person-based approach were used to guide intervention development, consulting with 87 patients with IBD and 60 nurses. These frameworks informed the selection and use of a theoretical model that subsequently guided cognitive behaviorally based intervention content. They also guided the design of tailored digital intervention pathways for individuals with IBD that matched the predominant symptoms.

Results

A transsymptomatic cognitive behavioral framework of symptom perpetuation was developed for the symptoms of fatigue, pain, and urgency in IBD. A logic model was used to define the intervention techniques. Patient feedback and qualitative interviews refined the website content and functionalities, including the use of visual aids, email reminders, and graphical tracking of symptoms. Nurse focus groups informed the volume and delivery model of the therapist facilitator support. Ratings of acceptability out of 10 following feasibility testing (31/87, 36%) demonstrated accessibility (scoring 9.43, SD 1.040), ease (scoring 8.07, SD 3.205), clarity, and the relevant tone of the intervention. The final intervention comprised 12 web-based sessions (8 core and 4 symptom-specific), with one 30-minute facilitator phone call following session 1 and subsequent on-site messaging.

Conclusions

The use of theory and integration of stakeholders’ views throughout informed the development of an evidence-based digital intervention for fatigue, pain, and urgency in IBD. This is the first web-based self-management intervention designed to address these multiple symptoms with the aim of improving the quality of life and reducing the symptom burden of IBD. The intervention is being tested in a large multicenter randomized controlled trial.

Trial Registration

ISRCTN Registry ISRCTN71618461; https://www.isrctn.com/ISRCTN71618461

Suppression of PTRF Alleviates Post-Infectious Irritable Bowel Syndrome via Downregulation of the TLR4 Pathway in Rats

Background: Accumulating evidence suggests that the polymerase I and transcript release factor (PTRF), a key component of the caveolae structure on the plasma membrane, plays a pivotal role in suppressing the progression of colorectal cancers. However, the role of PTRF in the development of functional gastrointestinal (GI) disorders remains unclear. Post-infectious irritable bowel syndrome (PI-IBS) is a common functional GI disorder that occurs after an acute GI infection. Here, we focused on the role of PTRF in the occurrence of PI-IBS and investigated the underlying mechanisms. Methods: Lipopolysaccharide (LPS) (5 μg/ml) was used to induce inflammatory injury in human primary colonic epithelial cells (HCoEpiCs). Furthermore, a rat model of PI-IBS was used to study the role of PTRF. Intestinal sensitivity was assessed based on the fecal water content. A two-bottle sucrose intake test was used to evaluate behavioral changes. Furthermore, shRNA-mediated knockdown of PTRF was performed both in vitro and in vivo. We detected the expression of PTRF in colonic mucosal tissues through immunohistochemistry (IHC), western blotting (WB), and immunofluorescence (IF) analysis. Luciferase activity was quantified using a luciferase assay. Co-localization of PTRF and Toll-like receptor 4 (TLR4) was detected using IF analysis. The activation of the signaling pathways downstream of TLR4, including the iNOs, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) pathways, was detected via WB. The levels of NO, IL-1β, IL-6, and TNF-α were measured using enzyme-linked immunosorbent assays. Results: LPS significantly induced PTRF expression and signaling downstream of TLR4, including p38, ERK, and JNK pathways, in HCoEpiCs. Moreover, shRNA-mediated knockdown of PTRF in HCoEpiCs significantly decreased the phosphorylation of JNK, ERK, and p38 and iNOS expression. In PI-IBS rats, the lack of PTRF not only reduced fecal water content and suppressed depressive behavior but also increased the body weight. Furthermore, we found a strong co-localization pattern for PTRF and TLR4. Consistently, the lack of PTRF impaired TLR4 signaling, as shown by the decreased levels of p-JNK, p-ERK, and p-p38, which are upstream factors involved in iNOS expression. Conclusion: PTRF promoted PI-IBS and stimulated TLR4 signaling both in vitro and in vivo. The results of this study not only enlighten the pathogenesis of PI-IBS but also help us understand the biological activity of PTRF and provide an important basis for the clinical treatment of PI-IBS by targeting PTRF.

A putative anti-inflammatory role for TRPM8 in irritable bowel syndrome-An exploratory study

BACKGROUND

Chronic and recurring pain is a characteristic symptom in irritable bowel syndrome (IBS). Altered signaling between immune cells and sensory neurons within the gut may promote generation of pain symptoms. As transient receptor potential melastatin 8 (TRPM8) agonists, such as L-menthol in peppermint oil, have shown to attenuate IBS pain symptoms, we began investigating potential molecular mechanisms.

METHODS

Colonic biopsy tissues were collected from patients with IBS and controls, in two separate cohorts. Immunohistochemistry was performed to identify TRPM8 localization. Quantitative PCR was performed to measure mucosal mRNA levels of TRPM8. In addition, functional experiments with the TRPM8 agonist icilin were performed ex vivo to examine cytokine release from biopsies. Daily diaries were collected to ascertain pain symptoms.

RESULTS

In biopsy tissue from IBS patients, we showed that TRPM8 immunoreactivity is colocalized with immune cells predominantly of the dendritic cell lineage, in close approximation to nerve endings, and TRPM8 protein and mRNA expression was increased in IBS patients compared to controls (p < 0.001). TRPM8 mRNA expression showed a significant positive association with abdominal pain scores (p = 0.015). Treatment of IBS patient biopsies with icilin reduced release of inflammatory cytokines IL-1β, IL-6, and TNF-α (p < 0.05).

CONCLUSIONS AND INFERENCES

These data indicate TRPM8 may have important anti-inflammatory properties and by this virtue can impact neuro-immune disease mechanisms in IBS.

A Prospective Multicenter Study on the Prevalence of Fructose Malabsorption in Patients with Chronic Inflammatory Bowel Disease

BACKGROUND AND AIMS

Patients with chronic inflammatory bowel disease (IBD) might have a higher prevalence of fructose malabsorption than healthy controls. This study's aim was to determine the prevalence and symptom severity of fructose malabsorption in patients with active and inactive IBD.

METHODS

The present study was a multicenter noninterventional diagnostic pilot trial. Two hundred fifty-one participants were recruited from 12 outpatient clinics for internal medicine across Germany and from the University of Kiel. Fructose malabsorption was diagnosed by hydrogen breath testing. Patients diagnosed with bacterial overgrowth, non-H2 producers, and patients who were tested positive for lactose malabsorption were excluded. Gastrointestinal symptoms during breath testing were evaluated using four-point subjective items to determine severity of bloating, abdominal pain, and diarrhea.

RESULTS

Two hundred five patients (45 with active IBD, 80 with IBD in remission, and 81 healthy controls) were analyzed. The number of patients diagnosed with fructose malabsorption - 35/44 (79.6%) in patients with active IBD, 59/80 (73.8%) inactive IBD, and 66/81 (81.5%) in healthy controls - did not differ between the groups (χ2 [2, N = 205] = 1.48, p = 0.48). However, abdominal pain was more frequent in patients with active IBD than patients with IBD in remission (z = -2.936, p = 0.010), and diarrhea was more frequent in patients with active IBD than in healthy controls (z = 2.489, p = 0.038).

CONCLUSIONS

Fructose malabsorption is not more common among patients with IBD than healthy subjects. However, the greater prevalence of patient-reported symptoms among patients with IBD may be of pathological and therapeutic relevance.

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.

Visceral hypersensitivity is together with psychological distress and female gender associated with severity of IBS-like symptoms in quiescent ulcerative colitis

BACKGROUND

A subset of ulcerative colitis (UC) patients in remission demonstrate IBS-like symptoms. Visceral hypersensitivity is a key pathophysiological mechanism in IBS, but its relevance to IBS-like symptoms in inactive UC remains unclear.

METHODS

UC patients in remission (UCR) were screened for IBS-like symptoms. Rectal sensitivity was assessed with rectal balloon distensions, with determination of sensory thresholds and unpleasantness/pain intensity ratings. Patients completed questionnaires evaluating gastrointestinal (GI) and psychological symptoms. Age- and gender-matched IBS subjects and healthy controls (HC) also underwent a rectal sensitivity test.

KEY RESULTS

We included 36 UCR patients (18 with IBS-like symptoms (UCR + IBS) and 18 without (UCR - IBS)), 36 IBS subjects, and 14 HC. UCR and IBS patients were more sensitive to rectal balloon distensions than HC, but no differences between UCR and IBS patients were observed. UCR + IBS patients had lower sensory thresholds and higher unpleasantness ratings than UCR - IBS. In UCR patients, the overall GI symptom severity, pain, and bloating, but not diarrhea, constipation or satiety, were associated with rectal sensitivity. In multivariate analyses, rectal sensitivity, psychological distress, and female gender were identified as factors independently associated with GI symptom severity. 61% of UCR patients demonstrated rectal hypersensitivity, and these patients more commonly reported at least mild bloating and pain, and overall GI symptoms, compared to those with normal rectal sensitivity.

CONCLUSION & INFERENCES

Visceral hypersensitivity was associated with IBS-like symptoms, in particular pain and bloating, in inactive UC. Together with psychological factors and female gender, visceral hypersensitivity seems to be involved in GI symptom generation in quiescent UC.

Critical evaluation of animal models of visceral pain for therapeutics development: A focus on irritable bowel syndrome

The classification of chronic visceral pain is complex, resulting from persistent inflammation, vascular (ischemic) mechanisms, cancer, obstruction or distension, traction or compression, and combined mechanisms, as well as unexplained functional mechanisms. Despite the prevalence, treatment options for chronic visceral pain are limited. Given this unmet clinical need, the development of novel analgesic agents, with defined targets derived from preclinical studies, is urgently needed. While various animal models have played an important role in our understanding of visceral pain, our knowledge is far from complete. Due to the complexity of visceral pain, this document will focus on chronic abdominal pain, which is the major complaint in patients with disorders of the gut-brain interaction, also referred to as functional gastrointestinal disorders, such as irritable bowel syndrome (IBS). Models for IBS are faced with challenges including a complex clinical phenotype, which is comorbid with other conditions including anxiety, depression, painful bladder syndrome, and chronic pelvic pain. Based upon the multifactorial nature of IBS with complicated interactions between biological, psychological, and sociological variables, no single experimental model recapitulates all the symptoms of IBS. This position paper will contextualize chronic visceral pain using the example of IBS and focus on its pathophysiology while providing a critical review of current animal models that are most relevant, robust, and reliable in which to screen promising therapeutics to alleviate visceral pain and delineate the gaps and challenges with these models. We will also highlight, prioritize, and come to a consensus on the models with the highest face/construct validity.

Lived experience in people with inflammatory bowel disease and comorbid anxiety and depression in the United Kingdom and Australia

This study explored the lived experience of people with inflammatory bowel disease and anxiety/depression. It utilised a deductive biopsychosocial framework. Overall, 24 patients and 20 healthcare professionals from two countries participated. In the United Kingdom, the main themes included (1) bidirectional relationship between inflammatory bowel disease and mental health, (2) the need for healthcare integration and (3) lack of awareness about the disease. In Australia, (1) the 'vicious cycle' of inflammatory bowel disease and psychosocial health, (2) the need for biopsychosocial healthcare integration and (3) the stigma of a hidden disease. Better communication around mental illness is essential in improving inflammatory bowel disease healthcare.

Antidepressants in inflammatory bowel disease

Gut-brain dysregulation has been recognized by the scientific community as being crucial to the understanding of chronic gastrointestinal conditions, and this has translated into the practice of a newly established discipline, psychogastroenterology. Along with psychotherapy, antidepressants (a subtype of central neuromodulators) have been proposed as treatments for gut-brain disorders that might benefit both psychological and gastrointestinal health. Antidepressants have been found to be effective for the treatment of comorbid anxiety and depression, pain and impaired sleep. Although the efficacy of antidepressants is well established in disorders of gut-brain interaction (DGBI), evidence is only now emerging in IBD. This Perspective discusses the use of antidepressants in DGBI and IBD, focusing on how what we have learnt about the role of antidepressants in DGBI could be applied to help optimize the management of IBD.

Distinct Microbial Populations Exist in the Mucosa-associated Microbiota of Diarrhea Predominant Irritable Bowel Syndrome and Ulcerative Colitis

GOALS

The goal of this study was to observe the bacterial colonization in the intestinal mucosa in the patients with diarrhea predominant irritable bowel syndrome (IBS-D) and ulcerative colitis (UC), and compare the mucosa-associated microbiota among the IBS-D patients, UC patients and the healthy control, and explore the correlation of the mucosa-associated microbiota with clinical manifestations.

STUDY

A total of 20 IBS-D patients, 28 patients with UC (16 active, 12 inactive) and 16 healthy subjects were enrolled in the study. They all underwent colonoscopies in the Gastrointestinal Endoscopy Center in the Second Affiliated Hospital of Xi'an Jiaotong University from June 2016 to October 2016. The mucosa specimens were taken at the junction of rectum and sigmoid colon for fluorescent in situ hybridization (FISH). Then the observed mucosa-associated microbiota was counted and compared.

RESULTS

(1) In the IBS-D patients, the mucosa-associated bacteria were found to colonize in the surface of mucosa and the adjacent mucin layer. And in active UC, Escherichia coli, and Bacteroides were found in the lamina propria, in addition to bacterial colonization in the above-mentioned areas. (2) The total count of mucosa-associated bacteria and the individual counts of E. coli, Clostridium, and Bacteroides were significantly increased, and Bifidobacteria significantly decreased (P<0.05) in the IBS-D patients and UC patients. Counts of Lactobacillus were decreased only in UC patients compared with the healthy control. And a significantly larger variation of the above-mentioned bacterial counts was found in the patients with UC, particularly in those with active UC, compared with those with IBS-D (P<0.05); the counts in the UC group were 1.3 to 5.3 times more or less than those in the IBS-D group. (3) Compared with healthy controls and IBS-D, the total count of bacteria and the individual counts of E. coli and Bacteroides in the lamina propria in active UC were significantly increased (P<0.05). (4) A significant negative correlation of the counts of Lactobacillus and Bifidobacteria with the defecation frequency and fecal characteristics (P<0.05) was found in the IBS-D patients; in those with UC, both the total count of bacteria and the individual counts of E. coli, Clostridium, Bacteroides, Lactobacillus, and Bifidobacteria were significantly correlated, positively or negatively, with the related clinical manifestations and the activity of the disease (P<0.05).

CONCLUSIONS

Compared with the healthy control, intestinal microecology was changed most obviously in UC with much smaller differences though in the same direction in IBS-D. The translocation of some bacteria into the lamina propria was found in UC, particularly in active UC. The changes of mucosa-associated microbiota were related more or less to some clinical manifestations in IBS-D and UC.

Symptoms compatible with functional bowel disorders are common in patients with quiescent ulcerative colitis and influence the quality of life but not the course of the disease

BACKGROUND

Whether patients with inactive ulcerative colitis (UC) have symptoms compatible with functional bowel disorders (FBDs) other than irritable bowel syndrome (IBS) is unclear. Our aim was to investigate the prevalence and burden of these symptoms and determine impact on the UC course.

METHODS

We used Mayo score, sigmoidoscopy and calprotectin (f-cal) to define remission in 293 UC patients. Presence of symptoms compatible with FBD, severity of gastrointestinal, extraintestinal and psychological symptoms, stress levels and quality of life (QoL) were measured with validated questionnaires. At 1 year later, remission was determined by modified Mayo score and f-cal in 171 of these patients. They completed the same questionnaires again.

RESULTS

A total of 18% of remission patients had symptoms compatible with FBD other than IBS, and 45% subthreshold symptoms compatible with FBD. The total burden of gastrointestinal symptoms in patients with symptoms compatible with FBD was higher than in patients without FBD (p < 0.001), which had negative impact on QoL (p = 0.02). These symptoms were not correlated with psychological distress, systemic immune activity or subclinical colonic inflammation and were not a risk factor for UC relapse during follow up.

CONCLUSION

Symptoms compatible with FBD other than IBS are common during UC remission influencing patients' QoL but not the UC course.

The "Biology-First" Hypothesis: Functional disorders may begin and end with biology-A scoping review

While it is generally accepted that gastrointestinal infections can cause functional disturbances in the upper and lower gastrointestinal tract-known as postinfectious irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD)-it has still not been widely recognized that such an infection can also initiate functional non-intestinal diseases, and that non-intestinal infections can provoke both intestinal and non-intestinal functional disturbances. We conducted a scoping review of the respective literature and-on the basis of these data-hypothesize that medically unexplained functional symptoms and syndromes following an infection may have a biological (genetic, endocrine, microbiological) origin, and that psychological and social factors, which may contribute to the disease "phenotype," are secondary to this biological cause. If this holds true, then the search for psychological and social theories and factors to explain why one patient develops a chronic functional disorder while another does not is-at least for postinfectious states-misleading and detracts from exploring and identifying the true origins of these essentially biological disorders. The biopsychosocial model may, as the term implies, always begin with biology, also for functional (somatoform) disorders.

Long-Term Gastrointestinal Consequences are Frequent Following Sporadic Acute Infectious Diarrhea in a Tropical Country: A Prospective Cohort Study

BACKGROUND

Postinfection irritable bowel syndrome (PI-IBS) and functional dyspepsia (PI-FD), though reported from the temperate countries, have not been studied in the tropics; PI-malabsorption syndrome (MAS), which mimics PI-IBS, is reported from the tropics. No report till date on PI-IBS excluded PI-MAS. We studied: (i) the frequency of continuing bowel dysfunction after acute gastroenteritis (AG), (ii) its predictors, and (iii) PI-MAS among patients with PI-IBS.

METHODS

345 consecutive subjects each, with AG and age- and gender-matched healthy controls were followed up 3-monthly for 12 months using a translated-validated questionnaire and functional gastrointestinal disorders (FGIDs) were diagnosed by Rome III criteria. Symptom duration >3 months but <6 months was diagnosed as chronic bowel dysfunction (CBD) and dyspeptic symptoms, respectively. MAS was diagnosed if 2/3 tests (D-xylose H₂ breath test, Sudan III-stained stool microscopy, and duodenal histology) were abnormal. Fecal microbiological studies were performed in 245/345 (71%) patients.

RESULTS

AG patients more often developed PI-IBS and PI-FD than controls (16.5 vs. 2.6% and 7.4 vs. 0.6%, respectively; p<0.001). Presence of FD was a risk factor for PI-IBS and IBS for PI-FD. On multivariate analysis, dyspeptic symptoms, CBD, and weight loss were the risk factors for PI-FGIDs. The frequency of PI-IBS following Vibrio cholera and other bacterial infection was comparable. Malabsorption was present among 2/23 (9%) patients with PI-IBS.

CONCLUSION

FGIDs are common after AG; dyspeptic symptoms, CBD, and weight loss were risk factors for PI-FGIDs. Vibrio cholerae infection caused PI-FGID, which was never reported. About 9 % patients fulfilling the criteria for PI-IBS had PI-MAS.

Systematic review: psychosocial factors associated with pain in inflammatory bowel disease

BACKGROUND

Pain is a frequently reported symptom of inflammatory bowel disease (IBD) experienced by patients in active disease and remission. Psychological factors play a significant role in pain, but have not been systematically reviewed in IBD.

AIM

To review psychosocial factors associated with pain in adults diagnosed with IBD.

METHODS

Electronic (PsycInfo, MEDLINE, EMBASE, Cochrane Library, CINAHL, Web of Science), and hand-searching were conducted February-May 2017. Two authors carried out screening and data extraction.

RESULTS

Fifteen studies including 5539 IBD patients were identified. Emotional, cognitive-behavioural and personality factors were associated with IBD-pain. Depression and anxiety were the most commonly explored constructs, followed by perceived stress and pain catastrophising, all of which were positively associated with greater pain. Greater abdominal pain was associated with a concurrent mood disorder over fivefold (OR 5.76, 95% CI 1.39, 23.89). Coping strategies and pain fear avoidance correlated with pain levels. Perceived social support (r = .26) and internal locus of control (r = .33) correlated with less pain. Patients reporting pain in IBD remission more frequently had an existing diagnosis of a mood disorder, a chronic pain disorder and irritable bowel syndrome. Six studies controlled for disease activity, of which 4 found that psychosocial factors significantly predicted pain. The majority of studies (n = 10) were of high quality.

CONCLUSION

Psychosocial factors appear to play a significant role in IBD-pain. Further research is required to explore psychosocial constructs in relation to IBD-pain, with use of validated pain measures, large sample sizes and clearer characterisation of disease activity.

Psychological Distress and Quality of Life in Pediatric Crohn Disease: Impact of Pain and Disease State

OBJECTIVES

For patients with Crohn disease (CD), symptom reporting may not coincide with disease state; patients in remission may continue to report symptoms and pain, whereas other patients may be symptom-free despite a flare. This phenomenon has been documented in adults but only recently assessed in pediatric patients. The present study assessed the role of pain reporting and disease state in pediatric patients with CD in understanding psychological distress and quality of life.

METHODS

Participants included 116 children and adolescents ages 8 to 18 years with CD who completed self-report questionnaires assessing pain, disease symptoms, depression, anxiety, functional disability, and quality of life. Physicians completed the Pediatric Crohn's Disease Activity Index to assess disease activity (scores ≤10 = remission, scores >10 = flare).

RESULTS

Approximately two thirds of participants reported pain concordant with disease state. For patients in remission, those with pain experienced significantly increased disability and decreased quality of life compared to patients in remission without pain. For patients in a flare, those without pain experienced significantly decreased disability and depressive symptoms, and improved quality of life compared to patients in a flare with pain.

CONCLUSIONS

For pediatric patients with CD, report of pain, while in remission or a flare, is associated with increased disability and reduced quality of life. Although levels of depression did not differ by disease state, depressive symptoms did differ by pain report (presence or absence) for those in a flare. Pain reporting in CD appears to be associated with both physical and psychological state and should be assessed regardless of disease activity.

Stress and brain functional changes in patients with Crohn's disease: A functional magnetic resonance imaging study

BACKGROUND

In Crohn's disease (CD) patients, stress is believed to influence symptoms generation. Stress may act via central nervous system pathways to affect visceral sensitivity and motility thus exacerbating gastrointestinal symptoms. The neural substrate underpinning these mechanisms needs to be investigated in CD. We conducted an explorative functional magnetic resonance imaging (fMRI) study in order to investigate potential differences in the brain stress response in CD patients compared to controls.

METHODS

17 CD patients and 17 healthy controls underwent a fMRI scan while performing a stressful task consisting in a Stroop color-word interference task designed to induce mental stress in the fMRI environment.

KEY RESULTS

Compared to controls, in CD patients the stress task elicited greater blood oxygen level dependent (BOLD) signals in the midcingulate cortex (MCC).

CONCLUSIONS & INFERENCES

The MCC integrate "high" emotional processes with afferent sensory information ascending from the gut. In light of these integrative functions, the stress-evoked MCC hyperactivity in CD patients might represent a plausible neural substrate for the association between stress and symptomatic disease. The MCC dysfunction might be involved in mechanisms of central disinhibition of nociceptive inputs leading to amplify the visceral sensitivity. Finally, the stress-evoked MCC hyperactivity might affect the regulation of intestinal motility resulting in exacerbation of disease symptoms and the autonomic and neuroendocrine regulation of inflammation resulting in enhanced inflammatory activity.

P2Y1R is involved in visceral hypersensitivity in rats with experimental irritable bowel syndrome

AIM

To evaluate the role of P2Y1R in visceral hypersensitivity in rats with experimental irritable bowel syndrome.

METHODS

A rat model of irritable bowel syndrome was generated by intra-colonic administration of acetic acid (AA) and assessed by histology and myeloperoxidase (MPO) activity assay. Then P2Y1R expression in the colonic tissue was detected by Western blot. In order to explore the regulatory role of P2Y1R in visceral hypersensitivity, an agonist (MRS2365) and an antagonist (MRS2179) of P2Y1R were intra-colonically administered and effects were tested through a colorectal distension test. The abdominal withdrawal reflex and abdominal electromyography were tested during the course.

RESULTS

Model assessment tests showed an obvious inflammatory reaction that appeared on the 2^nd d after the AA injection, and the inflammatory reaction gradually recovered and almost disappeared on the 7^th d. The model finished on day 8 and showed a clear feature of IBS that had no organic lesion. The average expression of P2Y1R was significantly higher in the AA group than in the naïve group (0.319 ± 0.02 vs 0.094 ± 0.016, P < 0.001). MRS2365 could effectively raise the colonic hypersensitivity status at intervention doses of 10 (AUC value from 0.30 ± 0.089 to 1.973 ± 0.127 mv·s, P < 0.01) and 100 μmol/L (AUC value from 0.290 ± 0.079 to 1.983 ± 0.195 mv·s, P < 0.01); MRS2179 could effectively reduce the hypersensitivity status at intervention dose of 100 μmol/L (from a mean baseline AUC value of 1.587 ± 0.099 mv·s to 0.140 ± 0.089 mv·s, P < 0.0001). Differences between the MRS2179 group (1.88 ± 1.45) and either the MRS2365 group (3.96 ± 0.19) or the combined treatment (MRS2179 and MRS2365) group (3.28 ± 0.11) were significant (P < 0.01).

CONCLUSION

P2Y1R plays a regulatory role in visceral hypersensitivity in rats with experimental IBS. Specific antagonists of P2Y1R may have potential therapeutic value in treating abdominal pain in IBS.

What's new in Rome IV?

The functional gastrointestinal disorders (FGIDs) are the most common disorders seen in Gastroenterology clinical practice. The Rome process has generated consensus definitions of FGIDS, allowing to subdivide patients into diagnostic categories based on the symptom pattern. The Rome IV consensus, presented in 2016, is the most recent update of this diagnostic scheme. This article summarizes the main changes, which include the use of epidemiology-based symptom thresholds to define FGIDs, characterization of FGIDS as disorders of Gut-Brain interaction, and updates of criteria for esophageal disorders, irritable bowel syndrome and Biliary and Sphincter of Oddi disorders based on scientific and technical progress made over the last decade. The Rome IV consensus provides a standard for clinical and research approach to FGIDS for the coming years.

Opioid Medications in the Management of Chronic Abdominal Pain

PURPOSE OF REVIEW

Chronic abdominal pain is a complex medical condition. The causes of chronic abdominal pain are extremely diverse ranging from chronic pancreatitis, Crohn's disease, to chronic pain with no clear etiology. Treatment of chronic abdominal pain remains a challenge in our clinical practice. While current interventions with celiac plexus blocks and pain medications provide some relief for these patients, but these treatments are typically less efficacious and limited by various adverse effects. Opioid medications are commonly used to manage chronic pain syndromes that are refectory to other pain management interventions. The potential problems related to opioids include misuse, abuse, constipation, nausea pruritus, et al. Moreover, according to the recent centers for disease (CDC) control report, opioid abuse has reached epidemic proportions in the USA (LJ P. Centers for Disease Control and Prevention. 2016) and accounted for 28,000 deaths in 2014. Rudd et al. (MMWR Morb Mortal Wkly Rep 64(50-51):1378-82, 2016) Given this current situation, it is apparent that a careful review of clinical evidences supporting the use of opioid medications is necessary to guide our treatment approaches in the management of complex chronic abdominal pain patients. This review is set out to analyze efficacy of opioid medications for chronic abdominal pain.

RECENT FINDINGS

The literature referenced was obtained via a computer search with Google Scholar, Pubmed, Medline, and EMbase. The search terms used included Opioid, Oxycodone, Buprenorphine, Morphine, Fentanyl, Oxymorphone, Hydromorphone, chronic abdominal pain, Crohn's disease, and pancreatitis. All studies were considered eligible for inclusion if they were clinical studies evaluating the efficacy of opioid medications for chronic abdominal pain. Two studies were found according to these criteria. Chronic abdominal pain is a challenging medical condition in our daily practice. This condition often requires opioid medications when other treatments fail. This review provided very limited clinical evidence to support long-term opioid use for chronic abdominal pain. Given recent CDC report of opioid epidemic, it is prudent to use the best medical practice with appropriate evaluation of psychological comorbidities, urine drug screening, prescription drug monitor, and opioid treatment agreements to minimize adverse side effects related to opioids. Furthermore, well-designed clinical trials are needed to evaluate the effectiveness of long-term use of opioid medications, and more clinical research on which opioid medication is more effective for chronic abdominal pain.

Prevalence and Impact of Functional Abdominal Pain Disorders in Children With Inflammatory Bowel Diseases (IBD-FAPD)

OBJECTIVES

We sought to describe the prevalence of the overlap of functional abdominal pain disorders (FAPDs) in children with inflammatory bowel diseases (IBDs), a condition we have designated as IBD-FAPD. We also aimed to describe the psychological profile of this group, and to assess predictors of disease and the impact of IBD-FAPD on quality of life.

METHODS

This cross-sectional prospective study included patients ages 8 to 18 years with a diagnosis of IBD. Disease activity was assessed by physician's global assessment, laboratory studies, and abbreviated Pediatric Crohn's Disease Activity Index or Pediatric Ulcerative Colitis Activity Index scoring. Age-appropriate validated questionnaires were used to diagnose FAPDs according to the Rome III criteria, depression, anxiety symptoms, and quality of life.

RESULTS

There were 128 patients recruited. Eighty-one (63%) completed questionnaires (36 girls; 45 boys; mean age 14.4 ± 2.6 years) (62 Crohn disease, 19 ulcerative colitis). The prevalence of IBD-FAPD in clinical remission was 26% (17 Crohn disease, 4 ulcerative colitis; 95% confidence interval: 20.6%-79.4%), with significantly more girls having IBD-FAPD (P = 0.038). Anxiety symptoms were in 14.3% of patients with IBD-FAPD (P = 0.06) and depression in 23.8% (P = 0.006). The average Pediatric Quality of Life Inventory Gastrointestinal Symptoms score for the IBD-FAPD group was significantly lower than those without FAPDs (71 vs 86.5, P = 0.008).

CONCLUSIONS

In our cohort, the prevalence of IBD-FAPD was 26%. This is the first study to assess all FAPDs using the Rome III criteria and to demonstrate increased anxiety, depression, and worse quality of life in children with IBD-FAPD. The identification of patients predisposed to IBD-FAPD may allow implementing strategies that could improve symptoms and quality of life.

Modifiable Risk Factors for Hospital Readmission Among Patients with Inflammatory Bowel Disease in a Nationwide Database

BACKGROUND

Previous studies suggest that disease activity alone does not reliably predict hospital readmission among patients with inflammatory bowel diseases (IBDs). Using a national database, we aimed to further describe the burden of readmissions for IBD and identify modifiable risk factors.

METHODS

We performed a retrospective cohort study using 2013 data from the Nationwide Readmission Database (NRD). Using International Classification of Diseases, ninth Revision, Clinical Modification (ICD-9-CM) codes, we identified adult patients with discharge diagnoses of ulcerative colitis or Crohn's disease and ascertained diagnoses of anxiety, depression, chronic pain, tobacco use, and other comorbidities during index admission. Logistic regression was used to estimate factors associated with hospital readmission.

RESULTS

Among 52,498 hospitalizations of patients with IBD (63% Crohn's disease and 37% ulcerative colitis), 12,407 (24%) were readmitted within 90 days of the index hospitalization, resulting in roughly $576 million in excess charges. In multivariable analysis of patients with Crohn's disease, anxiety (odds ratio [OR] 1.31, 95% confidence interval [CI], 1.21-1.43), depression (OR 1.27, 95% CI, 1.07-1.50), chronic pain (OR 1.31, 95% CI, 1.18-1.46), and tobacco abuse (OR 1.13, 95% CI, 1.06-1.22) were associated with a significant increase in odds of readmission. Among patients with ulcerative colitis, anxiety (OR 1.28, 95% CI, 1.14-1.45), depression (OR 1.35, 95% CI, 1.07-1.70), and chronic pain (OR 1.44, 95% CI, 1.21-1.73) were associated with a significant increase in odds of readmission.

CONCLUSIONS

Readmission occurs frequently in patients with IBD and is costly. Anxiety, depression, and chronic pain may represent targets for interventions to prevent 90-day hospital readmission in this population.

Prevalence and Impact of Inflammatory Bowel Disease-Irritable Bowel Syndrome on Patient-reported Outcomes in CCFA Partners

BACKGROUND

Inflammatory bowel disease (IBD) patients with persistent symptoms despite no or minimal inflammation are frequently described as having an overlap of IBD and irritable bowel syndrome (IBD-IBS). Limited data are available on how IBS impacts the individual patient with IBD. In this study, we aimed to evaluate the prevalence of IBD-IBS and investigate its impact on patient-reported outcomes.

METHOD

We performed a cross-sectional analysis within the CCFA Partners Study. Bivariate analyses and logistic regression models were used to investigate associations between IBD-IBS and various demographic, disease factors, and patient-reported outcomes including anxiety, depression, sleep disturbances, pain interference, and social satisfaction.

RESULTS

Of the 6309 participants included, a total of 1279 (20%) reported a coexisting IBS diagnosis. The prevalence of IBD-IBS in this cohort was similar within disease subtypes. A diagnosis of IBD-IBS was associated with higher narcotic use compared with those with no IBS diagnosis for both Crohn's disease, 17% versus 11% (P < 0.001) and ulcerative colitis/indeterminate colitis, 9% versus 5% (P < 0.001). Quality of life, as measured by Short Inflammatory Bowel Disease Questionnaire (SIBDQ) was lower in patients with IBD-IBS compared with those without. IBD-IBS diagnosis was associated with anxiety, depression, fatigue, sleep disturbances, pain interference, and decreased social satisfaction.

CONCLUSIONS

In this sample of patients with IBD, high prevalence of concomitant IBS diagnosis was observed. IBD-IBS diagnosis was associated with increased narcotic use and adverse patient-reported outcome. Appropriate diagnosis, treatment, and counseling may help improve the functional status of IBD-IBS patients and decrease narcotic use.

Acute colitis chronically alters immune infiltration mechanisms and sensory neuro-immune interactions

OBJECTIVE

Little is understood regarding how disease progression alters immune and sensory nerve function in colitis. We investigated how acute colitis chronically alters immune recruitment and the impact this has on re-activated colitis. To understand the impact of disease progress on sensory systems we investigated the mechanisms underlying altered colonic neuro-immune interactions after acute colitis.

DESIGN

Inflammation was compared in mouse models of health, acute tri-nitrobenzene sulphonic acid (TNBS) colitis, Remission and Reactivated colitis. Cytokine concentrations were compared by ELISA in-situ and in explanted colon tissue. Colonic infiltration by CD11b/F4-80 macrophage, CD4 T_HELPER (T_H) and CD8 T_CYTOTOXIC (T_C) and α₄β₇ expression on mesenteric lymph node (MLN) T_H and T_C was determined by flow cytometry. Cytokine and effector receptor mRNA expression was determined on colo-rectal afferent neurons and the mechanisms underlying cytokinergic effects on high-threshold colo-rectal afferent function were investigated using electrophysiology.

RESULTS

Colonic damage, MPO activity, macrophage infiltration, IL-1β and IL-6 concentrations were lower in Reactivated compared to Acute colitis. T_H infiltration and α₄β₇ expression on T_H MLN was increased in Remission but not Acute colitis. IFN-γ concentrations, T_H infiltration and α₄β₇ expression on T_H and T_C MLN increased in Reactivated compared to Acute colitis. Reactivated explants secreted more IL-1β and IL-6 than Acute explants. IL-6 and TNF-α inhibited colo-rectal afferent mechanosensitivity in Remission mice via a BK_Ca dependent mechanism.

CONCLUSIONS

Acute colitis persistently alters immune responses and afferent nerve signalling pathways to successive episodes of colitis. These findings highlight the complexity of viscero-sensory neuro-immune interactions in painful remitting and relapsing diseases.

P2Y Receptors Sensitize Mouse and Human Colonic Nociceptors

Activation of visceral nociceptors by inflammatory mediators contributes to visceral hypersensitivity and abdominal pain associated with many gastrointestinal disorders. Purine and pyrimidine nucleotides (e.g., ATP and UTP) are strongly implicated in this process following their release from epithelial cells during mechanical stimulation of the gut, and from immune cells during inflammation. Actions of ATP are mediated through both ionotropic P2X receptors and metabotropic P2Y receptors. P2X receptor activation causes excitation of visceral afferents; however, the impact of P2Y receptor activation on visceral afferents innervating the gut is unclear. Here we investigate the effects of stimulating P2Y receptors in isolated mouse colonic sensory neurons, and visceral nociceptor fibers in mouse and human nerve-gut preparations. Additionally, we investigate the role of Nav1.9 in mediating murine responses. The application of UTP (P2Y2 and P2Y4 agonist) sensitized colonic sensory neurons by increasing action potential firing to current injection and depolarizing the membrane potential. The application of ADP (P2Y1, P2Y12, and P2Y13 agonist) also increased action potential firing, an effect blocked by the selective P2Y1 receptor antagonist MRS2500. UTP or ADP stimulated afferents, including mouse and human visceral nociceptors, in nerve-gut preparations. P2Y1 and P2Y2 transcripts were detected in 80% and 56% of retrogradely labeled colonic neurons, respectively. Nav1.9 transcripts colocalized in 86% of P2Y1-positive and 100% of P2Y2-positive colonic neurons, consistent with reduced afferent fiber responses to UTP and ADP in Na(v)1.9(-/-) mice. These data demonstrate that P2Y receptor activation stimulates mouse and human visceral nociceptors, highlighting P2Y-dependent mechanisms in the generation of visceral pain during gastrointestinal disease.

Investigation of faecal volatile organic metabolites as novel diagnostic biomarkers in inflammatory bowel disease

BACKGROUND

The aetiology of inflammatory bowel disease (IBD) remains poorly understood. Recent evidence suggests an important role of gut microbial dysbiosis in IBD, and this may be associated with changes in faecal volatile organic metabolites (VOMs).

AIM

To describe the changes in the faecal VOMs of patients with IBD and establish their diagnostic potential as non-invasive biomarkers.

METHODS

Faecal samples were obtained from 117 people with Crohn's disease (CD), 100 with ulcerative colitis (UC), and 109 healthy controls. Faecal VOMs were extracted using solid-phase micro-extraction and analysed by gas chromatography mass spectrometry. Data analysis was carried out using partial least squares-discriminate analysis (PLS-DA) to determine class membership based on distinct metabolomic profiles.

RESULTS

The PLS-DA model showed clear separation of active CD from inactive disease and healthy controls (P < 0.001). Heptanal, 1-octen-3-ol, 2-piperidinone and 6-methyl-2-heptanone were up-regulated in the active CD group [variable important in projection (VIP) score 2.8, 2.7, 2.6 and 2.4, respectively], while methanethiol, 3-methyl-phenol, short-chain fatty acids and ester derivatives were found to be less abundant (VIP score of 3.5, 2.6, 1.5 and 1.2, respectively). The PLS-DA model also separated patients with small bowel CD from healthy controls and those with colonic CD from UC (P < 0.001). In contrast, less distinct separation was observed between active UC, inactive UC and healthy controls.

CONCLUSIONS

Analysis of faecal volatile organic metabolites can provide an understanding of gut metabolomic changes in IBD. It has the potential to provide a non-invasive means of diagnosing IBD, and can differentiate between UC and CD.

Overlapping irritable bowel syndrome and inflammatory bowel disease: less to this than meets the eye?

Though distinct in terms of pathology, natural history and therapeutic approach, irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) have some features in common. These include shared symptomatology and largely similar demographics. However, in most instances, clinical presentation, together with laboratory, imaging and endoscopic findings will readily permit the differentiation of active IBD from IBS. More problematic is the situation where a subject with IBD, in apparent remission, continues to complain of symptoms which, in aggregate, satisfy commonly employed criteria for the diagnosis of IBS. Access to methodologies, such the assay for levels of calprotectin in feces, now allows identification of ongoing inflammation in some such individuals and prompts appropriate therapy. More challenging is the IBD patient with persisting symptoms and no detectable evidence of inflammation; is this coincident IBS, IBS triggered by IBD or an even more subtle level of IBD activity unrecognized by available laboratory or imaging methods? Arguments can be advanced for each of these proposals; lacking definitive data, this issue remains unresolved. The occurrence of IBS-type symptoms in the IBD patient, together with some data suggesting a very subtle level of 'inflammation' or 'immune activation' in IBS, raises other questions: is IBS a prodromal form of IBD; and are IBS and IBD part of the spectrum of the same disease? All of the available evidence indicates that the answer to both these questions should be a resounding 'no'. Indeed, the whole issue of overlap between IBS and IBD should be declared moot given their differing pathophysiologies, contrasting natural histories and divergent treatment paths. The limited symptom repertoire of the gastrointestinal tract may well be fundamental to the apparent confusion that has, of late, bedeviled this area.

The voltage-gated sodium channel NaV 1.9 in visceral pain

BACKGROUND

Visceral pain is a common symptom for patients with gastrointestinal (GI) disease. It is unpleasant, debilitating, and represents a large unmet medical need for effective clinical treatments. Recent studies have identified NaV 1.9 as an important regulator of afferent sensitivity in visceral pain pathways to mechanical and inflammatory stimuli, suggesting that NaV 1.9 could represent an important therapeutic target for the treatment of visceral pain. This potential has been highlighted by the identification of patients who have an insensitivity to pain or painful neuropathies associated with mutations in SCN11A, the gene encoding voltage-gated sodium channel subtype 1.9 (NaV 1.9).

PURPOSE

Here, we address the role of NaV 1.9 in visceral pain and what known human NaV 1.9 mutants can tell us about NaV 1.9 function in gut physiology and pathophysiology.

Diagnosis and management of functional symptoms in inflammatory bowel disease in remission

Inflammatory bowel disease (IBD) patients in remission may suffer from gastrointestinal symptoms that resemble irritable bowel syndrome (IBS). Knowledge on this issue has increased considerably in the last decade, and it is our intention to review and summarize it in the present work. We describe a problematic that comprises physiopathological uncertainties, diagnostic difficulties, as IBS-like symptoms are very similar to those produced by an inflammatory flare, and the necessity of appropriate management of these patients, who, although in remission, have impaired quality of life. Ultimately, from almost a philosophical point of view, the presence of IBS-like symptoms in IBD patients in remission supposes a challenge to the traditional functional-organic dichotomy, suggesting the need for a change of paradigm.

Immune dysregulation in the functional gastrointestinal disorders

Gastrointestinal conditions may be broadly classified into two: organic and functional disease, with functional disorders accounting for the majority of patients with chronic gastrointestinal symptoms. Functional gastrointestinal disorders (FGIDs) present with no obvious pathology or well-accepted biochemical mechanism and, as such, treatment strategies are limited and focus on symptoms rather than cure. Irritable bowel syndrome and functional dyspepsia are the most widely recognised FGIDs, and there is a growing body of evidence to suggest an underlying inflammatory phenotype in subsets with these conditions. Here, we discuss the current knowledge of immune involvement in FGIDs and the commonalities between the different manifestations of FGIDs and propose a new hypothesis, potentially defining an underlying immunopathological basis of these conditions.

Infectious Gastroenteritis as a Risk Factor for Tropical Sprue and Malabsorption: A Case-Control Study

BACKGROUND

Previous studies have linked an increase in functional and pathological gastrointestinal (GI) disorders following antecedent infectious gastroenteritis (IGE), yet studies of other chronic GI disorders such as tropical sprue (TS) and intestinal malabsorption (IM) are lacking. This study was performed to evaluate the association between documented IGE and the risk of TS and IM using a matched case-control study.

METHODS

The odds of IGE (exposure) among subjects with TS and IM were compared to the odds of exposure in matched controls. Data were obtained from the Defense Medical Surveillance System. Incidence was estimated based on the number of active duty military personnel, and conditional logistic regression models were used to evaluate the relationship between IGE and TS/IM while adjusting for potential confounders.

RESULTS

The overall incidence of TS and IM was 0.24 and 1.98 per 100,000 person-years, respectively. After adjusting for important covariates, prior IGE was associated with an increase in the odds of TS (odds ratio (OR) 36.64) and IM (OR 3.93) (p < 0.001). Other covariates demonstrating an increased risk were being of Caucasian race, having greater than high school education, and service in military branches other than the Army.

CONCLUSION

Overall, this study demonstrates the first significant estimates that a case of antecedent IGE is associated with an increased risk of TS and IM in an active duty military population. Ultimately, acquisition of TS or IM has the potential to decrease operational efficiency, which may have a significant impact on deployed military missions.

Hypnotherapy for Inflammatory Bowel Disease Across the Lifespan

Inflammatory bowel disease (IBD) is an autoimmune disorder characterized by lifelong relapsing gastrointestinal symptoms and associated with high rates of chronic pain, depression, and anxiety. In this review the author covers the existing literature including randomized controlled studies, open trials, and case reports as well as expert opinion in evaluating how hypnotherapy can be most beneficial in adolescents and adults with IBD. Hypnotherapy evidence for functional gastrointestinal disorders (FGIDs) is also reviewed as many of the gut-focused hypnotherapy (GHT) approaches used in IBD trials were developed for this latter population. Collectively, the strongest evidence of use of hypnotherapy is its association with reduced IBD-related inflammation and improved health-related quality of life with mixed results in terms of its effects on psychological and pain outcomes in adults with IBD. Studies of hypnotherapy for FGID symptoms show consistently more positive results. Post-operative hypnotherapy may also be helpful based on findings in other surgical samples. Adolescents with IBD have not been as systematically studied but small case series support the use of hypnotherapy to improve inflammation and pain. Future studies are needed to better delineate the specific brain-gut pathways which are most influenced by hypnotherapy in the IBD population and to investigate the longer-term course of the positive short-term findings.

Proinflammatory and anti-inflammatory cytokine profile in pediatric patients with irritable bowel syndrome

BACKGROUND AND OBJECTIVES

There is evidence that patients with irritable bowel syndrome (IBS) have a low degree of inflammation in the intestinal mucosa. The aim of the study was to evaluate the profile of pro- and anti-inflammatory cytokines in plasma in Mexican pediatric patients with IBS.

PATIENTS AND METHODS

Fifteen patients with IBS according to Rome III criteria for childhood and 15 healthy children, matched by age and sex, were included in the study. Plasma levels of tumoral necrosis factor alpha (TNF-α), interleukins 10 and 12 (IL-10, IL-12) and transforming growth factor beta (TGF-β) were quantified and compared between groups.

RESULTS

Plasma levels of IL-10 were lower in patients with IBS (86.07+21.3 pg/mL vs. 118.71+58.62 pg/mL: P=.045) and IL-12 levels were higher in patients with IBS compared to the control group of healthy children (1,204.2±585.9 pg/mL vs. 655.04±557.80 pg/mL; P=.011). The IL-10/IL-12 index was lower in patients with IBS (0.097±0.07 vs. 0.295±0.336; P=.025). Plasma concentration of TGF-β was higher in patients with IBS (545.67±337.69 pg/mL vs. 208.48±142.21 pg/mL; P=.001). There was no difference in plasma levels of TNF-α between groups.

CONCLUSIONS

This study suggests that children with IBS have a state of altered immune regulation. This is consistent with the theory of low-grade inflammatory state in these patients. Further studies are needed to elucidate the role played by these cytokines, specifically TGF-β in the pathogenesis of IBS.

Persistent pain in chronically ill children without detectable disease activity

Children with organic diseases may experience persistent pain in the presence of controlled disease, as evidenced by little or no measurable disease activity or inflammation. Historically, dualistic definitions of pain have informed standard diagnostic approaches to persistent pain; aggressive investigation and treatment targeting underlying disease, even in the absence of evidence indicating disease escalation. Evidence across disease populations, in children with inflammatory bowel disease, sickle cell disease, and juvenile idiopathic arthritis indicates that persistent pain in these conditions may be better conceptualized as functional in nature, potentially resulting from disordered somatosensory processing including central sensitization. Applying a biopsychosocial understanding of persistent pain and multidisciplinary functional pain management strategies may lead to improved health outcomes.

Abdominal pain and the neurotrophic system in ulcerative colitis

BACKGROUND

We undertook a study to test the hypothesis that inflammation alters peripheral sensory mechanisms, thereby contributing to chronic abdominal pain in ulcerative colitis (UC).

METHODS

Patients with UC and healthy individuals rated abdominal pain using a visual analog scale and completed surveys describing anxiety or depression (Hospital Anxiety and Depression Score) and gastrointestinal symptoms (Rome III questionnaire). Patient age, sex, and severity of inflammation were determined. Rectal biopsies were processed using immunohistochemical techniques to assess nerve fiber density and real-time PCR to determine transcript expression of neurotrophins (nerve growth factor, glial cell-derived neurotrophic factor, artemin, neurturin), ion channels (transient receptor potential vanilloid type 1, transient receptor potential ankyrin 1) and inflammatory mediators (tumor necrosis factor-α, interleukin [IL]-1β, IL-6, IL-10, IL-17).

RESULTS

A total of 77 patients with UC (27 female, 50 male) and 21 controls (10 female, 11 male) were enrolled. Patients with UC with pain had significantly higher depression scores than controls and patients with UC without pain (P < 0.05). There was no correlation between any of the inflammatory markers and pain scores. Visual analog scale pain scores significantly correlated with younger age, higher depression scores, increased expression of neurturin and decreased expression of transient receptor potential ankyrin 1 in the mucosa. Mucosal nerve fiber density did not correlate with any measures of inflammation or pain. Only higher depression scores independently predicted pain in UC (r > 0.5).

CONCLUSIONS

We did not observe changes in mucosal innervation and did not see a significant relationship between nerve fiber density, inflammatory mediators, neurotrophic factors, or mucosal ion channel expression and pain. In contrast, the importance of depression as the only independent predictor of pain ratings mirrors functional disorders, where central processes significantly contribute to symptom development and/or perpetuation.

Relationship between vagal tone, cortisol, TNF-alpha, epinephrine and negative affects in Crohn's disease and irritable bowel syndrome

Crohn's disease (CD) and irritable bowel syndrome (IBS) involve brain-gut dysfunctions where vagus nerve is an important component. The aim of this work was to study the association between vagal tone and markers of stress and inflammation in patients with CD or IBS compared to healthy subjects (controls). The study was performed in 73 subjects (26 controls, 21 CD in remission and 26 IBS patients). The day prior to the experiment, salivary cortisol was measured at 8:00 AM and 10:00 PM. The day of the experiment, subjects completed questionnaires for anxiety (STAI) and depressive symptoms (CES-D). After 30 min of rest, ECG was recorded for heart rate variability (HRV) analysis. Plasma cortisol, epinephrine, norepinephrine, TNF-alpha and IL-6 were measured in blood samples taken at the end of ECG recording. Compared with controls, CD and IBS patients had higher scores of state-anxiety and depressive symptomatology. A subgroup classification based on HRV-normalized high frequency band (HFnu) as a marker of vagal tone, showed that control subjects with high vagal tone had significantly lower evening salivary cortisol levels than subjects with low vagal tone. Such an effect was not observed in CD and IBS patients. Moreover, an inverse association (r =  -0.48; p<0.05) was observed between the vagal tone and TNF-alpha level in CD patients exclusively. In contrast, in IBS patients, vagal tone was inversely correlated with plasma epinephrine (r =  -0.39; p<0.05). No relationship was observed between vagal tone and IL-6, norepinephrine or negative affects (anxiety and depressive symptomatology) in any group. In conclusion, these data argue for an imbalance between the hypothalamus-pituitary-adrenal axis and the vagal tone in CD and IBS patients. Furthermore, they highlight the specific homeostatic link between vagal tone and TNF-alpha in CD and epinephrine in IBS and argue for the relevance of vagus nerve reinforcement interventions in those diseases.

Diagnosis and treatment of narcotic bowel syndrome

With increased prescription of opioids has come increased recognition of adverse consequences, including narcotic bowel syndrome (NBS). Characterized by incompletely controlled abdominal pain despite continued or increasing doses of opioids, NBS is estimated to occur in 4.2-6.4% of patients chronically taking opioids. Patients with NBS have a high degree of comorbid psychiatric illness, catastrophizing and disability; comorbid substance abuse must also be considered among this population. NBS should be distinguished from opioid-induced bowel disorder, which results from the effects of opioids on gastrointestinal motility and secretion. By contrast, the mechanisms of NBS are probably centrally mediated and include glial cell activation, bimodal opioid modulation in the dorsal horn, descending facilitation of pain and the glutaminergic system. Few treatments have been rigorously studied. A trial of opioid detoxification resulted in complete detoxification for the vast majority of patients with reduction in pain symptoms; however, despite improvement in pain, approximately half of patients returned to opioid use within 3 months. Improved strategies are needed to identify patients who will respond to detoxification and remain off opioids. Comorbid psychiatric and substance abuse disorders are barriers to durable response after detoxification and should be actively sought out and treated accordingly. An effective patient-physician relationship is essential.

Involvement of interleukin-17A-induced hypercontractility of intestinal smooth muscle cells in persistent gut motor dysfunction

BACKGROUND AND AIM

The etiology of post-inflammatory gastrointestinal (GI) motility dysfunction, after resolution of acute symptoms of inflammatory bowel diseases (IBD) and intestinal infection, is largely unknown, however, a possible involvement of T cells is suggested.

METHODS

Using the mouse model of T cell activation-induced enteritis, we investigated whether enhancement of smooth muscle cell (SMC) contraction by interleukin (IL)-17A is involved in postinflammatory GI hypermotility.

RESULTS

Activation of CD3 induces temporal enteritis with GI hypomotility in the midst of, and hypermotility after resolution of, intestinal inflammation. Prolonged upregulation of IL-17A was prominent and IL-17A injection directly enhanced GI transit and contractility of intestinal strips. Postinflammatory hypermotility was not observed in IL-17A-deficient mice. Incubation of a muscle strip and SMCs with IL-17A in vitro resulted in enhanced contractility with increased phosphorylation of Ser19 in myosin light chain 2 (p-MLC), a surrogate marker as well as a critical mechanistic factor of SMC contractility. Using primary cultured murine and human intestinal SMCs, IκBζ- and p38 mitogen-activated protein kinase (p38MAPK)-mediated downregulation of the regulator of G protein signaling 4 (RGS4), which suppresses muscarinic signaling of contraction by promoting inactivation/desensitization of Gαq/11 protein, has been suggested to be involved in IL-17A-induced hypercontractility. The opposite effect of L-1β was mediated by IκBζ and c-jun N-terminal kinase (JNK) activation.

CONCLUSIONS

We propose and discuss the possible involvement of IL-17A and its downstream signaling cascade in SMCs in diarrheal hypermotility in various GI disorders.

Long-term prognosis of clinical symptoms and health-related quality of life in microscopic colitis: a case-control study

BACKGROUND

Microscopic colitis, comprising collagenous colitis (CC) and lymphocytic colitis (LC), is a common cause of chronic diarrhoea. The long-term prognosis is not well described.

AIM

To study outcome of symptoms and health-related quality of life (HRQoL).

METHODS

A case-control study using a postal questionnaire with three population-based controls per patient matched for age, sex and municipality. HRQoL was assessed by the Short Health Scale (SHS). Patients in clinical remission, defined as a mean of <3 stools/day, were evaluated separately (CC; n = 72, LC; n = 60).

RESULTS

The study included 212 patients and 627 matched controls. Median disease duration was 5.9 (range 0.5-27) years and 6.4 (0.3-14.8) years for CC and LC respectively. Abdominal pain, fatigue, arthralgia, myalgia, faecal incontinence and nocturnal defecation were significantly more prevalent in CC patients compared with controls. These differences persisted in CC patients in clinical remission with respect to abdominal pain (36% vs. 21%), fatigue (54% vs. 34%), arthralgia (61% vs. 41%) and myalgia (53% vs. 37%). In LC patients, abdominal pain, fatigue, faecal incontinence and nocturnal defecation were more prevalent compared with controls. In LC patients in clinical remission, fatigue was more prevalent compared with controls (54% vs. 37%). These differences were statistically significant (P < 0.05). All four HRQoL dimensions (symptom burden, social function, disease-related worry, general well-being) were impaired in patients with active CC and LC.

CONCLUSIONS

Although considered to be in clinical remission, patients with microscopic colitis suffer from persisting symptoms such as abdominal pain, fatigue, arthralgia or myalgia several years after diagnosis.