Overlap between functional GI disorders and other functional syndromes: what are the underlying mechanisms?

Prevalence of functional disorders across Europe: a systematic review and meta-analysis

Functional Disorders (FD) refer to persistent somatic symptoms caused by changes in the functioning of bodily processes. Previous findings suggest that FD are highly prevalent, but overall prevalence rates for FD in European countries are scarce. Therefore, the aim of the present work was to estimate the point prevalence of FD in adult general populations. PubMed and Web of Science were searched from inception to June 2022. A generalized linear mixed-effects model for statistical aggregation was used for statistical analyses. A standardized quality assessment was performed, and PRISMA guidelines were followed. A total of 136 studies were included and systematically synthesized resulting in 8 FD diagnoses. The large majority of studies was conducted in the Northern Europe, Spain, and Italy. The overall point prevalence for FD was 8.78% (95% CI from 7.61 to 10.10%) across Europe, with the highest overall point prevalence in Norway (17.68%, 95% CI from 9.56 to 30.38%) and the lowest in Denmark (3.68%, 95% CI from 2.08 to 6.43%). Overall point prevalence rates for specific FD diagnoses resulted in 20.27% (95% CI from 16.51 to 24.63%) for chronic pain, 9.08% (95% CI from 7.31 to 11.22%) for irritable bowel syndrome, and 8.45% (95% CI from 5.40 to 12.97%) for chronic widespread pain. FD are highly prevalent across Europe, which is in line with data worldwide. Rates implicate the need to set priorities to ensure adequate diagnosis and care paths to FD patients by care givers and policy makers.

Functional neurological disorder is common in patients attending chronic pain clinics

BACKGROUND AND PURPOSE

Chronic pain is a common comorbidity in those with functional neurological disorder (FND); however, the prevalence and characteristics of FND in those with chronic pain is unknown.

METHODS

A retrospective electronic records review was made of consecutive new patients attending a chronic pain clinic of a regional service. Clinical features, medication for and outcome of chronic pain, any lifetime diagnoses of functional disorders, FND, and psychiatric disorders, and undiagnosed neurological symptoms were recorded.

RESULTS

Of 190 patients attending the chronic pain clinic, 32 (17%) had a lifetime diagnosis of FND and an additional 11 (6%) had undiagnosed neurological symptoms. Pain patients with comorbid FND were more likely to have chronic primary pain (88% with FND, 44% without FND, p < 0.0001), widespread chronic primary pain (53%, 15%, p < 0.00001), and depression (84%, 52%, p < 0.005) and less likely to have a pain-precipitating event (19% vs. 56%, p < 0.001). However, there was no significant difference between these patients in opiate prescription, benzodiazepine prescription, or pain outcome.

CONCLUSIONS

This first study of FND in a chronic pain patient population found a remarkably high prevalence of FND (17%) and is possibly an underestimation. The size of the overlap indicates that FND and chronic pain research fields are likely to have a lot to learn from each other.

Intestinal bacteria associated with irritable bowel syndrome and chronic fatigue

The etiology of irritable bowel syndrome (IBS) is unknown. Abnormal intestinal bacterial profiles and low bacterial diversity appear to play important roles in the pathophysiology of IBS. This narrative review was designed to present recent observations made relating to fecal microbiota transplantation (FMT), which implicate possible roles of 11 intestinal bacteria in the pathophysiology of IBS. The intestinal abundances of nine of these bacteria increased after FMT in patients with IBS, and these increases were inversely correlated with IBS symptoms and fatigue severity. These bacteria were Alistipes spp., Faecalibacterium prausnitzii, Eubacterium biforme, Holdemanella biformis, Prevotella spp., Bacteroides stercoris, Parabacteroides johnsonii, Bacteroides zoogleoformans, and Lactobacillus spp. The intestinal abundances of two bacteria were decreased in patients with IBS after FMT and were correlated with the severity of IBS symptoms and fatigue (Streptococcus thermophilus and Coprobacillus cateniformis). Ten of these bacteria are anaerobic and one (Streptococcus thermophilus) is facultative anaerobic. Several of these bacteria produce short-chain fatty acids, especially butyrate, which is used as an energy source by large intestine epithelial cells. Moreover, it modulates the immune response and hypersensitivity of the large intestine and decreases intestinal cell permeability and intestinal motility. These bacteria could be used as probiotics to improve these conditions. Protein-rich diets could increase the intestinal abundance of Alistipes, and plant-rich diet could increase the intestinal abundance of Prevotella spp., and consequently improve IBS and fatigue.

Deficient butyrate-producing capacity in the gut microbiome is associated with bacterial network disturbances and fatigue symptoms in ME/CFS

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by unexplained debilitating fatigue, cognitive dysfunction, gastrointestinal disturbances, and orthostatic intolerance. Here, we report a multi-omic analysis of a geographically diverse cohort of 106 cases and 91 healthy controls that revealed differences in gut microbiome diversity, abundances, functional pathways, and interactions. Faecalibacterium prausnitzii and Eubacterium rectale, which are both recognized as abundant, health-promoting butyrate producers in the human gut, were reduced in ME/CFS. Functional metagenomics, qPCR, and metabolomics of fecal short-chain fatty acids confirmed a deficient microbial capacity for butyrate synthesis. Microbiome-based machine learning classifier models were robust to geographic variation and generalizable in a validation cohort. The abundance of Faecalibacterium prausnitzii was inversely associated with fatigue severity. These findings demonstrate the functional nature of gut dysbiosis and the underlying microbial network disturbance in ME/CFS, providing possible targets for disease classification and therapeutic trials.

Persistent Pelvic Pain in Patients With Endometriosis

As our understanding of chronic pain conditions, including endometriosis-related pain and chronic pelvic pain evolves, the evaluation and management of patients should reflect our increasing appreciation of the role of central sensitization, comorbid conditions and biopsychosocial factors on the pain experience and treatment outcomes. This review provides a systematic approach to persistent pain in patients with endometriosis. Expanding the evaluation and treatment of endometriosis-related pain by all health care providers could limit unnecessary surgical interventions and best meet our patient's needs.

Overlaps with bladder pain syndrome and irritable bowel syndrome are associated with higher symptom burden and reduced quality of life in functional dyspepsia

BACKGROUND

Functional dyspepsia and bladder pain syndrome are well-known to overlap with irritable bowel syndrome. Whether functional dyspepsia overlaps with bladder pain syndrome remains unknown. Our aim was to evaluate the presence of bladder pain syndrome in functional dyspepsia patients and its impact.

METHODS

All consecutive patients with investigated dyspeptic symptoms in our tertiary care center between March 2015 and November 2018 were studied. Functional dyspepsia and irritable bowel syndrome were diagnosed according to Rome III and IV criteria while bladder pain syndrome was diagnosed using ESSIC criteria. Validated questionnaires were filled to assess quality of life (GIQLI), anxiety and depression (HADS), sleep (PSQI), and insomnia (ISI). Dyspeptic symptoms severity was assessed individually for eight dyspeptic complaints.

KEY RESULTS

Among 1453 patients with dyspeptic symptoms, 61.4% fulfilled Rome criteria for functional dyspepsia. Bladder pain syndrome was present in 16.0% of the patients not fulfilling diagnostic criteria for functional dyspepsia, 22.2% of patients with functional dyspepsia alone, and 36.4% of patients with overlapping functional dyspepsia and irritable bowel syndrome (p-values &lt;0.0001). In patients with bladder pain syndrome overlapping with functional dyspepsia, dyspeptic symptoms severity, anxiety, depression, and insomnia levels were higher while quality of life and sleep quality were reduced (p-values &lt;0.0001). These results were even more pronounced in case of overlap with irritable bowel syndrome (p-values &lt;0.0001).

CONCLUSIONS AND INFERENCES

Bladder pain syndrome is present in 26.9% of functional dyspepsia patients and is associated with higher gastrointestinal, psychological distresses, and sleep symptom burdens, and with reduced quality of life.

Review article: diagnostic and therapeutic approach to persistent abdominal pain beyond irritable bowel syndrome

BACKGROUND

Persistent abdominal pain (PAP) poses substantial challenges to patients, physicians and healthcare systems. The possible aetiologies of PAP vary widely across organ systems, which leads to extensive and repetitive diagnostic testing that often fails to provide satisfactory answers. As a result, widely recognised functional disorders of the gut-brain interaction, such as irritable bowel syndrome and functional dyspepsia, are often diagnosed in patients with PAP. However, there are a number of less well-known differential diagnoses that deserve consideration.

AIM

To provide a comprehensive update on causes of PAP that are relatively rare in occurrence.

METHODS

A literature review on the diagnosis and management of some less well-known causes of PAP.

RESULTS

Specific algorithms for the diagnostic work-up of PAP do not exist. Instead, appropriate investigations tailored to patient medical history and physical examination findings should be made on a case-by-case basis. After a definitive diagnosis has been reached, some causes of PAP can be effectively treated using established approaches. Other causes are more complex and may benefit from a multidisciplinary approach involving gastroenterologists, pain specialists, psychologists and physiotherapists. This list is inclusive but not exhaustive of all the rare or less well-known diseases potentially associated with PAP.

CONCLUSIONS

Persistent abdominal pain (PAP) is a challenging condition to diagnose and treat. Many patients undergo repeated diagnostic testing and treatment, including surgery, without achieving symptom relief. Increasing physician awareness of the various causes of PAP, especially of rare diseases that are less well known, may improve patient outcomes.

Altered Effective Connectivity of Resting-State Networks by Tai Chi Chuan in Chronic Fatigue Syndrome Patients: A Multivariate Granger Causality Study

Numerous evidence has shown that patients with chronic fatigue syndrome (CFS) have changes in resting brain functional connectivity, but there is no study on the brain network effect of Tai Chi Chuan intervention in CFS. To explore the influence of Tai Chi Chuan exercise on the causal relationship between brain functional networks in patients with CFS, 21 patients with CFS and 19 healthy controls were recruited for resting-state functional magnetic resonance imaging (rs-fMRI) scanning and 36-item Short-Form Health Survey (SF-36) scale assessment before and after 1month-long training in Tai Chi Chuan. We extracted the resting brain networks using the independent component analysis (ICA) method, analyzed the changes of FC in these networks, conducted Granger causality analysis (GCA) on it, and analyzed the correlation between the difference causality value and the SF-36 scale. Compared to the healthy control group, the SF-36 scale scores of patients with CFS were lower at baseline. Meanwhile, the causal relationship between sensorimotor network (SMN) and default mode network (DMN) was weakened. The above abnormalities could be improved by Tai Chi Chuan training for 1 month. In addition, the correlation analyses showed that the causal relationship between SMN and DMN was positively correlated with the scores of Role Physical (RP) and Bodily Pain (BP) in CFS patients, and the change of causal relationship between SMN and DMN before and after training was positively correlated with the change of BP score. The findings suggest that Tai Chi Chuan is helpful to improve the quality of life for patients with CFS. The change of Granger causality between SMN and DMN may be a readout parameter of CFS. Tai Chi Chuan may promote the functional plasticity of brain networks in patients with CFS by regulating the information transmission between them.

Review article: rethinking the "ladder" approach to reflux-like symptom management in the era of PPI "resistance" - a multidisciplinary perspective

BACKGROUND

Despite widespread adoption of potent acid suppression treatment with proton pump inhibitors (PPI) for reflux-like symptoms, persistent symptoms are commonly reported in primary care and community studies.

AIMS

This multidisciplinary review critically evaluates how the management of reflux-like symptoms could better reflect their multifactorial pathophysiology.

METHODS

A panel of experts (from general practice, gastroenterology and gastropsychology) attended a series of workshops to review current management and propose a framework for the provision of more individualised care.

RESULTS

It was agreed that the perceptual (as well as the physiological) causes of reflux-like symptoms should be considered at the start of management, not as a last resort when all else has failed. A short course of PPI is a pragmatic approach to address reflux-like symptoms, but equally important is counselling about the gut-brain axis and provision of symptom-specific behavioural interventions for those who show signs of somatisation, hypervigilance or co-existing disorders of gut-brain interaction. Other low-harm interventions such as lifestyle and dietary advice, should also be better integrated into care at an early stage. Multidisciplinary care management programmes (including dietary, weight loss, exercise and behavioural intervention) should be developed to promote greater self-management and take advantage of the general shift toward the use of remotely accessed health care resources.

CONCLUSIONS

Management of reflux-like symptoms should be adapted to reflect the advances in knowledge about the multifactorial aetiology of these symptoms, addressing both acid-related and behavioural components early in management. The time has come to treat the patient, not the "disease".

Kappa Opioid Receptor Blockade in the Amygdala Mitigates Pain Like-Behaviors by Inhibiting Corticotropin Releasing Factor Neurons in a Rat Model of Functional Pain

Functional pain syndromes (FPS) occur in the absence of identifiable tissue injury or noxious events and include conditions such as migraine, fibromyalgia, and others. Stressors are very common triggers of pain attacks in various FPS conditions. It has been recently demonstrated that kappa opioid receptors (KOR) in the central nucleus of amygdala (CeA) contribute to FPS conditions, but underlying mechanisms remain unclear. The CeA is rich in KOR and encompasses major output pathways involving extra-amygdalar projections of corticotropin releasing factor (CRF) expressing neurons. Here we tested the hypothesis that KOR blockade in the CeA in a rat model of FPS reduces pain-like and nocifensive behaviors by restoring inhibition of CeA-CRF neurons. Intra-CeA administration of a KOR antagonist (nor-BNI) decreased mechanical hypersensitivity and affective and anxiety-like behaviors in a stress-induced FPS model. In systems electrophysiology experiments in anesthetized rats, intra-CeA application of nor-BNI reduced spontaneous firing and responsiveness of CeA neurons to peripheral stimulation. In brain slice whole-cell patch-clamp recordings, nor-BNI increased feedforward inhibitory transmission evoked by optogenetic and electrical stimulation of parabrachial afferents, but had no effect on monosynaptic excitatory transmission. Nor-BNI decreased frequency, but not amplitude, of spontaneous inhibitory synaptic currents, suggesting a presynaptic action. Blocking KOR receptors in stress-induced FPS conditions may therefore represent a novel therapeutic strategy.

Gastric herpes simplex virus type 1 infection is associated with functional gastrointestinal disorders in the presence and absence of comorbid fibromyalgia: a pilot case-control study

PURPOSE

Animal studies have linked gastric herpesvirus infections to symptoms associated with functional gastrointestinal disorders (FGIDs). Herpesviruses have also been hypothesized to contribute to fibromyalgia (FM), a chronic pain syndrome frequently comorbid with FGIDs. The purpose of this study was to compare the prevalence of gastric herpesvirus infection in patients with FGIDs, with and without comorbid FM, to that of controls.

METHODS

For this pilot case-control study, we enrolled 30 patients who met both the Rome IV diagnostic criteria for one or more FGIDs and the American College of Rheumatology 2010 criteria for FM, 15 patients with one or more FGIDs without comorbid FM, and 15 control patients. Following endoscopic examination, gastric biopsies were analyzed for herpesvirus DNA and protein, Helicobacter pylori infection, and histological evidence of gastritis. Importantly, the viral nonstructural protein ICP8 was used as a marker to differentiate cell-associated actively replicating virus from latent infection and/or free virus passing through the GI tract.

RESULTS

Gastric herpes simplex virus type 1 (HSV-1) infection, as indicated by ICP8 presence, was significantly associated with FGIDs in the presence (OR 70.00, 95% CI 7.42-660.50; P < .001) and absence (OR 38.50, 95% CI 3.75-395.40; P < .001) of comorbid FM. Neither histological gastritis nor H. pylori infection were found to be associated with FGIDs or FM.

CONCLUSIONS

HSV-1 infection was identified in gastric mucosal biopsies from patients with diverse FGIDs, with and without comorbid FM. Larger, multi-center studies investigating the prevalence of this association are warranted.

GABAB Receptors and Pain

A substantial fraction of the human population suffers from chronic pain states, which often cannot be sufficiently treated with existing drugs. This calls for alternative targets and strategies for the development of novel analgesics. There is substantial evidence that the G protein-coupled GABA_B receptor is involved in the processing of pain signals and thus has long been considered a valuable target for the generation of analgesics to treat chronic pain. In this review, the contribution of GABA_B receptors to the generation and modulation of pain signals, their involvement in chronic pain states as well as their target suitability for the development of novel analgesics is discussed.

[Individuals with sub-health status have obviously unbalanced structure of the intestinal flora: analysis of 150 nursing staff members]

OBJECTIVE

To explore the difference in intestinal flora composition between individuals with sub-health status and healthy subjects.

METHODS

From November, 2020 to May, 2021, a total of 150 nursing staff members in Nanfang Hospital were selected for this study, including 75 participants with sub-health status (SHS group) and 75 healthy participants (control group). Fecal samples were collected from all the participants for analysis of the diversity and species composition of the intestinal flora using high-throughput sequencing for V3-V4 region of 16S rRNA gene.

RESULTS

The results of α diversity analysis showed no significant difference in Chao1 index between the two groups (P=0.619), but the Shannon index was significantly higher in SHS group than in the control group (P < 0.001). The results of β diversity analysis showed significant differences in the community structure between the SHS group and the control group (R=0.227, P=0.001). At the phylum level, the intestinal flora in the two groups were composed mainly of Bacteroidota, Firmicutes and Actinobacteriata, and of Prevotella, Bacteroides, Blautia and Faecalibacterium at the genus level. Species difference analysis identified significant differences in the relative abundance between the two groups in 4 phyla, 3 classes, 3 orders, 3 families and 3 genera (P < 0.05).

CONCLUSION

Compared with healthy subjects, the individuals with sub-health status have obviously unbalanced structure of the intestinal flora.

Review article: irritable bowel syndrome: natural history, bowel habit stability and overlap with other gastrointestinal disorders

Symptoms of irritable bowel syndrome (IBS) characteristically fluctuate over time. We aimed to review the natural history of IBS and IBS subgroups including bowel habit disturbances, and the overlap of IBS with other gastrointestinal disorders. The community incidence of IBS is approximately 67 per 1000 person years. The prevalence of IBS is stable over time because symptoms fluctuate and there is a portion who experience resolution of their GI symptoms similar in number to those developing new-onset IBS. The proportion who report resolution of symptoms varies amongst population-based studies from 17% to 55%. There is evidence of substantial movement between subtypes of IBS. For example in a clinical trial cohort, only one in four patients retained their baseline classification throughout the study periods, two in three moved between IBS-C (constipation) and IBS-M (mixed), while over half switched between IBS-D (diarrhoea) and IBS-M. The least stable group was IBS-M. There are very limited data on drivers of bowel habit change in IBS. There are emerging evidence fluctuations in intestinal immune activity might account for symptom variability over time. It is of clinical importance to recognise the substantial overlap of IBS symptoms with other gastrointestinal syndromes including gastro-oesophageal reflux disease. This is important to ensure the correct clinical diagnosis of IBS is made and patients are not over investigated. Knowledge of the natural history, stability of subgroups and overlap of IBS with other gastrointestinal conditions should be considered in therapeutic decision making.

Central sensitization and severity of gastrointestinal symptoms in irritable bowel syndrome, chronic pain syndromes, and inflammatory bowel disease

BACKGROUND

Central sensitization has been suggested as an explanation of the wide range of gastrointestinal and extraintestinal symptoms commonly seen in irritable bowel syndrome (IBS). In this study, the presence and level of central sensitization, and its association to gastrointestinal (GI) symptoms were explored in IBS in comparison with control groups.

METHODS

We investigated patients with IBS (n = 215), chronic pain disorders (n = 36), and inflammatory bowel disease (IBD) (n = 40) and volunteers without chronic diseases (n = 112). The Central Sensitization Inventory (CSI) was translated and validated in Swedish and used together with the Highly Sensitive Person (HSP) scale to measure the presence and level of central sensitization. Furthermore, severity of GI symptoms (GSRS-IBS and IBS-SSS), and anxiety and depression (HAD) were determined.

KEY RESULTS

The Swedish translation of CSI demonstrated excellent validity. Central sensitization, defined by validated cut-off levels for CSI and HSP, was common in the whole cohort (40% and 28%) and in IBS (57% and 35%). Study participants with central sensitization had more severe GI symptoms, anxiety and depression, than participants without central sensitization. Strong associations were seen between CSI and GI symptom severity in the whole cohort (GSRS-IBS: partial η²  = 0.455, p < 0.001; IBS-SSS: partial η²  = 0.408, p < 0.001), with decreasing strength in patients with chronic pain, IBD, IBS, and volunteers.

CONCLUSION AND INFERENCES

Central sensitization was common in IBS and associated with GI symptom severity, but with stronger associations in chronic pain disorders and IBD. This implies that other mechanisms may be of equal or greater importance for GI symptom severity in IBS.

Physiological mechanisms of unexplained (functional) gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) encompass a range of complex conditions with similar clinical characteristics and no overt pathology. Recent recognition of sub-clinical pathologies in FGIDs, in conjunction with physiological and biochemical abnormalities including increased intestinal permeability, microbial profile alterations, differences in metabolites and extra-intestinal manifestations of disease, call into question the designation of these conditions as 'functional'. This is despite significant heterogeneity in both symptom profile and specifics of reported physiological abnormalities hampering efforts to determine defined mechanisms that drive onset and chronicity of symptoms. Instead, the literature demonstrates these conditions are disorders of homeostatic imbalance, with disruptions in both host and microbial function and metabolism. This imbalance is also associated with extraintestinal abnormalities including psychological comorbidities and fatigue that may be a consequence of gastrointestinal disruption. Given the exploitation of such abnormalities will be crucial for improved therapeutic selection, an enhanced understanding of the relationship between alterations in function of the gastrointestinal tract and the response of the immune system is of interest in identifying mechanisms that drive FGID onset and chronicity. Considerations for future research should include the role of sex hormones in regulating physiological functions and treatment responses in patients, as well as the importance of high-level phenotyping of clinical, immune, microbial and physiological parameters in study cohorts. There is opportunity to examine the functional contribution of the microbiota and associated metabolites as a source of mechanistic insight and targets for therapeutic modulation.

Individuals requiring orthognathic surgery have more depression and pain than controls

The objective of this study was to evaluate if individuals with dentofacial deformities (DFD) who require orthognathic surgery are affected more by depression and pain. A case-control study was performed with 195 individuals. In the DFD group, 145 individuals with Class II and III malocclusion requiring orthognathic surgery were selected. The control group was composed of 50 individuals with no DFD. All patients were diagnosed according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Data were analyzed with a significance level of 0.05. The DFD group more often presented severe depression (p = 0.020) and chronic pain (p = 0.017). They also presented higher prevalence of Nonspecific Physical Symptoms Including Pain (P = 0.002) and Nonspecific Physical Symptoms Excluding Pain (p = 0.002). Concerning TMD symptoms, the DFD group had more myofascial (p = 0.002) and articular pain (p = 0.041). Therefore, the results of this study suggest that depression and pain are more common in individuals with DFD requiring orthognathic surgery compared with individuals without DFD.

Amygdala microglia modify neuronal plasticity via complement C1q/C3-CR3 signaling and contribute to visceral pain in a rat model

Stress can trigger symptoms in patients with irritable bowel syndrome (IBS). Previously we demonstrated that chronic psychological stress induced microglial remodeling in the central nucleus of amygdala (CeA) and contributed to the development of visceral hypersensitivity via synaptic engulfment. However, the specific signaling mechanisms that microglia depend upon to recognize target neurons to facilitate visceral pain remain unknown. Here, we test the hypothesis that the microglia in the CeA contribute to chronic stress-induced visceral hypersensitivity via complement C1q/C3-CR3 signaling-mediated synaptic remodeling. In male and female Fischer-344 rats, micropellets of corticosterone (CORT) or cholesterol (control) were stereotaxically implanted bilaterally onto the CeA. After 7 days, microglial C1q, complement receptor 3 (CR3) expression, and microglia-mediated synaptic engulfment were assessed via RNAscope, quantitative PCR, and immunofluorescence. The microglial inhibitor minocycline, CR3 antagonist neutrophil inhibitory factor (NIF), or vehicle were daily infused into the CeA following CORT implantations. Visceral sensitivity was assessed via a visceromotor response (VMR) to graded pressures of isobaric colorectal distension (CRD). Our results suggest that chronic exposure to elevated CORT in the CeA induced visceral hypersensitivity and amygdala microglial morphological remodeling. CORT increased microglial C1q and CR3 expression and increased microglia-mediated synaptic engulfment. Both groups of animals with minocycline or NIF infusions reversed microglia-mediated synaptic remodeling and attenuated CORT-induced visceral hypersensitivity. Our findings demonstrate that C1q/C3-CR3 signaling is critical for microglia-mediated synaptic remodeling in the CeA and contributes to CORT-induced visceral hypersensitivity.NEW & NOTEWORTHY Patients with irritable bowel syndrome (IBS) show altered amygdala activity. We showed previously that stress induces visceral hypersensitivity partially through microglia-modulated synaptic plasticity in the central nucleus of the amygdala (CeA). Our current data suggest that the C1q/C3-CR3 cascade initiates microglia-mediated synaptic remodeling in the CeA. Blocking C3-CR3 interaction attenuates stress-induced visceral hypersensitivity. These findings uncover a role of microglia-synapse signaling in the brain-gut regulation and support a future therapeutic target to treat visceral pain.

The Natural History of Chronic Unexplained Gastrointestinal Disorders and Gastroesophageal Reflux During 20 Years: A US Population-Based Study

OBJECTIVE

To explore the natural history of chronic unexplained gastrointestinal (GI) symptoms and to determine the longitudinal trends of prevalence during a 20-year period in a single US community.

METHODS

Between January 1, 1990, and December 31, 2009, valid self-report questionnaires of GI symptoms were mailed to randomly selected cohorts of a community. The study used respondents who answered questions on 1 or more of 3 surveys (initial, 1990-1992; second, 2003-2004; and third, 2008-2009). The trends of prevalence of GI symptoms over time were analyzed in responders who completed 3 surveys, and the natural history or transition was evaluated.

RESULTS

The overall prevalence of major symptom groupings including gastroesophageal reflux disease was consistent among residents in a community on 3 survey time points (1990-1992, 2003-2004, and 2008-2009). The transitions of GI symptoms were common in 228 patients who responded to all 3 surveys; only 29% had the same symptom category in 3 surveys; otherwise, symptoms changed over time, resolving, recurring, or transitioning to another disorder. Observed proportions of symptom transitions were significantly different from expected during 20 years (P<.001). Higher non-GI somatic symptom scores were significantly associated with both symptom transitions (odds ratio, 3.9; 95% CI, 1.38 to 10.77) and having sustained symptoms (odds ratio, 12.7; 95% CI, 4.62 to 34.90).

CONCLUSION

The overall population prevalence of chronic unexplained GI symptoms is stable, but in individuals, transitions seem to be the rule. As these various GI syndromes appear to be so intimately interconnected, the common underlying pathogenesis may account for a major subgroup of chronic unexplained GI disorders.

Is Irritable Bowel Syndrome Considered in Clinical Trials on Physical Therapy Applied to Patients with Temporo-Mandibular Disorders? A Scoping Review

The aim of the current scoping review was to identify if the presence of irritable bowel syndrome was included as eligibility criteria of participants included in clinical trials investigating the effects of physical therapy in individuals with temporomandibular pain disorders (TMDs). A systematic electronic literature search in the Web of Science database was conducted. Scientifically relevant, randomized clinical trials (those cited in other studies at least 5 times, or clinical trials published in high-impact journals, i.e., first and second quartiles (Q1-Q2) of any category of the Journal Citation Report (JCR)) evaluating the effects of any physical therapy intervention in patients with TMDs were included. The Physiotherapy Evidence Database (PEDro) scale was used to evaluate the methodological quality of the selected trials. Authors affiliated to a clinical or non-clinical institution, total number of citations, objective, sex/gender, age, and eligibility criteria in each article were extracted and analyzed independently by two authors. From a total of 98 identified articles, 12 and 19 clinical trials were included according to the journal citation criterion or JCR criterion, respectively. After removing duplicates, a total of 23 trials were included. The PEDro score ranged from 4 to 8 (mean: 6.26, SD: 1.48). Based on the eligibility criteria of the trials systematically reviewed, none considered the presence of comorbid irritable bowel syndrome in patients with TMDs. The comorbidity between TMDs and irritable bowel syndrome is not considered within the eligibility criteria of participants in highly cited clinical trials, or published in a high-impact journal, investigating the effects of physical therapy in TMDs.

NUTRITIONAL STATUS, QUALITY OF LIFE AND LIFE HABITS OF WOMEN WITH IRRITABLE BOWEL SYNDROME: A CASE-CONTROL STUDY

BACKGROUND

Irritable bowel syndrome is a functional and chronic gastrointestinal disorder that may cause abdominal pain and altered bowel habits, affecting the nutritional status and quality of life of its carriers. Its prevalence is high, affecting about 10% to 15% of the general population in developed countries, being more prevalent in women than in men in the proportion 2:1.

OBJECTIVE

The aim of our study was to compare the profile of body adiposity, life habits, and the quality of life of women with irritable bowel syndrome with a healthy control group.

METHODS

Case-control study on 70 women, 34 with irritable bowel syndrome and 36 healthy. We applied the "Irritable Bowel Syndrome Quality of Life Questionnaire"to assess quality of life. Body adiposity was assessed from body mass index, waist circumference, and waist-to-hip ratio. We investigated the self-reporting of gastrointestinal symptoms with food deemed as problematic for carriers of irritable bowel syndrome and the presence of typical comorbidities. Assessment of life habits included: practice of physical activities, alcoholism, smoking, daytime sleepiness, and exclusion of foods from the feeding routine. For statistical analysis we used the IBM SPSS program, with a significance level at 5%.

RESULTS

There was higher volume of central and general adiposity in the case group compared with the control group (P<0.05). Cases presented a higher chance of developing IBS-related comorbidities (P<0.05). About of 80% of patients with irritable bowel syndrome have excluded some food from the diet (P<0.01) and the total amount of troublesome foods varied from 7 to 21 (P<0.01). The case group featured worse quality of life compared with the control (P<0.05).

CONCLUSION

Compared to the control group, women with irritable bowel syndrome showed greater body adiposity, higher frequency of comorbidities, greater restriction on the consumption of problematic foods and worse quality of life.

Associations among gastroesophageal reflux disease, mental disorders, sleep and chronic temporomandibular disorder: a case-control study

BACKGROUND

Temporomandibular disorders (TMDs) are a family of pain-related disorders associated with impaired function in the jaw, temporomandibular joint and muscles of mastication. Our objectives were to evaluate the association between chronic TMD and gastresophageal reflux disease (GERD) and to determine whether mental disorders or undermined sleep mediates this association.

METHODS

We conducted a case-control study involving 1522 consecutive adult patients with chronic TMD and 1522 matched controls from 2 hospitals in China. All participants were aged between 18 and 70 years and were recruited from July 2017 to April 2018 Chronic TMD was diagnosed by trained dentists using the criteria in the Orofacial Pain Prospective Evaluation and Risk Assessment Study. Trained gastroenterologists made blinded diagnoses of GERD according to the Montreal definition and classification (at least 2 d of mild symptoms, or 1 d of moderate or severe symptoms per week). We used validated questionnaires to evaluate psychological status and sleep quality.

RESULTS

Of the study participants, we identified 132 patients and 61 controls with GERD. Using conditional logistic regression analysis, we identified GERD as a risk factor for TMD (odds ratio 2.74, 95% confidence interval 1.88 to 3.98). Mediation analyses identified that somatization, anxiety and undermined sleep moderately mediated the relation between TMD and GERD.

INTERPRETATION

Our study suggests that symptomatic GERD is associated with chronic, painful TMD, and somatization, anxiety and undermined sleep mediate this association to a certain extent. Due consideration should be given to the evaluation and management of gastrointestinal symptoms and mental disorders in the combined therapy for painful TMD.

Distinct associations of DSM-5 Somatic Symptom Disorder, the Diagnostic Criteria for Psychosomatic Research-Revised (DCPR-R) and symptom severity in patients with irritable bowel syndrome

OBJECTIVE

The clinical management of high symptom severity is a challenging task with patients with functional somatic disorders. We investigated the extent to which DCPR-revised (DCPR-R) syndromes and the DSM-5 category of Somatic Symptom Disorder (SSD) were able to predict symptom severity in 203 consecutive tertiary care patients with irritable bowel syndrome (IBS).

METHOD

Semistructured interview were used for assessing DCPR-R and validated scales for SSD (combining PHQ-12 and WI-7), severity of symptoms (IBS-SSS), psychological distress (HADS), and psychosocial functioning (SF-12).

RESULTS

Compared to moderate severity (IBS-SSS = 175-300), patients in the high range of severity (IBS-SSS > 300) had significantly more DCPR-R syndromes (particularly alexithymia and persistent somatization), higher psychological distress, and poorer psychosocial functioning, but showed no difference for SSD. DCPR-R, particularly alexithymia and persistent somatization, significantly and independently predicted IBS severity by explaining 18.5% of the IBS-SSS variance with large effect size (d = 1.18), after controlling for covariables. Conversely, SSD was not able to significantly predict IBS severity.

CONCLUSIONS

This study highlights the need of an integrative approach in the medical setting. Psychosomatic factors play a relevant role in the individual perception of symptom severity and should be carefully evaluated for clinical management of functional syndromes.

Prevalence of functional dyspepsia-like symptoms in ulcerative colitis patients in clinical remission and overlap with irritable bowel syndrome-like symptoms

Objective: Quiescent ulcerative colitis (UC) patients often have irritable bowel syndrome (IBS)-like symptoms and we recently showed that the prevalence of IBS-like symptoms in UC patients in clinical remission was significantly higher as compared to healthy control subjects. However, the prevalence of functional dyspepsia (FD)-like symptoms in quiescent UC patients remains unknown. The purpose of this study was to evaluate the prevalence of FD-like symptoms and the overlap with IBS-like symptoms in such patients.Materials and Methods: We reanalyzed the records of UC patients in remission using the subject cohort from our previous study. Clinical remission was defined as a clinical activity index (CAI) value ≤4 for at least 6 months. Diagnoses of FD- and IBS-like symptoms were evaluated by questionnaire according to the Rome III criteria.Results: One hundred seventy-two UC patients in clinical remission and 330 healthy control subjects were analyzed. Of the 172 patients, 9 (5.2%) met the criteria of FD, which was comparable with the controls (22/330, 6.7%). The prevalence rate of FD-like symptoms in UC patients with IBS-like symptoms (7/46, 15.2%) was lower as compared to that of the control subjects (6/16, 37.5%). On the other hand, a high percentage of the UC patients with FD-like symptoms also had IBS-like symptoms (7/9, 77.8%).Conclusions: Although the prevalence of FD-like symptoms in quiescent UC patients with IBS-like symptoms was low, UC patients with FD-like symptoms frequently had IBS-like symptoms.

Epigenetic Mechanisms in Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a brain-gut axis disorder characterized by abdominal pain and altered bowel habits. IBS is a multifactorial, stress-sensitive disorder with evidence for familial clustering attributed to genetic or shared environmental factors. However, there are weak genetic associations reported with IBS and a lack of evidence to suggest that major genetic factor(s) contribute to IBS pathophysiology. Studies on animal models of stress, including early life stress, suggest a role for environmental factors, specifically, stress associated with dysregulation of corticotropin releasing factor and hypothalamus-pituitary-adrenal (HPA) axis pathways in the pathophysiology of IBS. Recent evidence suggests that epigenetic mechanisms, which constitute molecular changes not driven by a change in gene sequence, can mediate environmental effects on central and peripheral function. Epigenetic alterations including DNA methylation changes, histone modifications, and differential expression of non-coding RNAs (microRNA [miRNA] and long non-coding RNA) have been associated with several diseases. The objective of this review is to elucidate the molecular factors in the pathophysiology of IBS with an emphasis on epigenetic mechanisms. Emerging evidence for epigenetic changes in IBS includes changes in DNA methylation in animal models of IBS and patients with IBS, and various miRNAs that have been associated with IBS and endophenotypes, such as increased visceral sensitivity and intestinal permeability. DNA methylation, in particular, is an emerging field in the realm of complex diseases and a promising mechanism which can provide important insights into IBS pathogenesis and identify potential targets for treatment.

Necrotizing enterocolitis: It's not all in the gut

Necrotizing enterocolitis is the leading cause of death due to gastrointestinal disease in preterm neonates, affecting 5–12% of neonates born at a very-low birth weight. Necrotizing enterocolitis can present with a slow and insidious onset, with some neonates displaying early symptoms such as feeding intolerance. Treatment during the early stages includes bowel rest and careful use of antibiotics, but surgery is required if pneumoperitoneum and intestinal perforation occur. Mortality rates among neonates requiring surgery are estimated to be 20–30%, mandating the development of non-invasive and reliable biomarkers to predict necrotizing enterocolitis before the onset of clinical signs. Such biomarkers would allow at-risk neonates to receive maximal preventative therapies such as careful nutritional consideration, probiotics, and increased skin-to-skin care.

Impact statement

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease; its high mortality rate mandates the development of non-invasive biomarkers to predict NEC before its onset. This review summarizes the pathogenesis, prevention, unresolved issues, and long-term outcomes of NEC.

Effects of a comprehensive self-management intervention on extraintestinal symptoms among patients with IBS

OBJECTIVE

Adults with irritable bowel syndrome (IBS) often report extraintestinal pain, fatigue, and sleep disturbances in addition to abdominal pain. Few interventions have sought to reduce these extraintestinal symptoms within the IBS population. To address this, we compared the effects of a comprehensive self-management (CSM) intervention to a control intervention (usual care) on extraintestinal pain, fatigue, and sleep disturbances among patients with IBS.

METHOD

Data were obtained from 243 IBS patients participating in two CSM intervention trials. Daily symptom diaries were collected at baseline, 3 and 6 months post-randomization. Daily symptoms of headache, backache, muscle pain, joint pain, fatigue, sleepiness during the day, sleep quality, and refreshed by sleep were analyzed. Analysis of covariance was used to determine the effects of the intervention on each symptom at 3 and 6 months controlling for 'study' and baseline symptom levels.

RESULTS

Patients in the CSM intervention group reported decreased symptoms of fatigue, sleep disturbances, backache and headache compared to usual care at 3 and 6 months. The CSM group also reported significantly decreased joint pain at 3 months compared to usual care, but not 6 months. No significant difference was found for muscle pain.

CONCLUSIONS

An existing CSM intervention is effective in reducing fatigue and sleep disturbances. However, mixed results for extraintestinal pain indicates a need to better differentiate between underlying mechanisms. Addressing such symptoms is important to decrease the overall burden of IBS, reduce health care expenditures, and improve patients' quality of life.

TRIAL REGISTRATION

NCT00907790; NCT00167635.

Coexistence of Alterations of Gastrointestinal Function and Mechanical Allodynia in the Reserpine-Induced Animal Model of Fibromyalgia

BACKGROUND

Fibromyalgia (FM) is a disorder characterized by widespread chronic pain as core symptom and a broad range of comorbidities. Despite the prevalence of gastrointestinal (GI) comorbidities in patients with FM, GI functions have rarely been investigated in animal models of FM.

AIMS

The purpose of the present study is to investigate the coexistence of alterations of GI function in the reserpine-induced myalgia (RIM) rat, a validated FM model associated with disruption of monoamine system.

METHODS

Paw withdrawal threshold (von Frey hair test) was assessed as pain-associated indicator. Gastric emptying (¹³C breath test), small intestinal transit (charcoal meal test), and fecal water content were investigated as GI functions.

RESULTS

The specific regimen of reserpine for the RIM rat, i.e., 1 mg/kg s.c., once daily for three consecutive days, caused a reduction of paw withdrawal threshold (i.e., mechanical allodynia) on days 3, 5, and 7 after the first injection. The ¹³CO₂ excreted from the RIM rat was significantly increased on day 7. The RIM rat exhibited an acceleration of small intestinal transit on day 5. Fecal water content collected from the RIM rat was significantly increased on days 3 and 5. The amount of noradrenaline was significantly decreased in GI tissues on days 3, 5, and 7 in the RIM rat. Conclusions This study revealed that accelerated gastric emptying, accelerated small intestinal transit, and increase in fecal water content coexist with mechanical allodynia in the RIM rat, simulating the coexistence of chronic pain and alterations of GI function in patients with FM.

Review article: the incidence and risk factors for irritable bowel syndrome in population-based studies

BACKGROUND

In the absence of prior gastrointestinal infection, the risk factors for irritable bowel syndrome (IBS) are not well established.

AIM

To identify the incidence and risk factors for IBS in general population samples METHODS: Narrative review of population-based studies. Electronic databases were searched using the keywords "incidence," "onset," "epidemiology," "population," "risk factors" with "irritable bowel syndrome" with subsequent hand searching. Inclusion criteria were: population-based, adults, prospective design (including retrospective case cohorts), clinical or research diagnosis of IBS and exclusion of individuals who had IBS prior to recruitment.

RESULTS

Of 1963 papers, 38 were included; all provided data on risk factors, 27 reported incidence. The median incidence of physician-diagnosed IBS in 19 general population cohorts was 38.5 per 10 000 person-years (interquartile range = 20-45.3). In 14 cohorts with specific medical disorders, median incidence was 92 per 10 000 person-years (IQR: 73.9-119). Apart from gastroenteritis, the most common risk factors were other medical disorders, female sex, age (both young and old), anxiety and depression, life events/stress, frequent healthcare use, pain and sleep disorders. The results were conflicting for alcohol consumption, smoking and BMI. Incidence rates were similar in different countries but risk factors differed.

CONCLUSIONS

Incidence rates were generally lower than previous estimates reflecting physician-diagnosed IBS. The results highlight the importance of other medical and psychosocial problems in the onset of IBS in addition to prior gastrointestinal infections. Aetiological research could be enhanced by studying the underlying mechanisms relating to all of these risk factors.

Correlation between the motility of the proximal antrum and the high-frequency power of heart rate variability in freely moving rats

BACKGROUND

Cardiac vagal tone can be monitored non-invasively via electrocardiogram measurements of the high-frequency power spectrum of heart rate variability (HF-HRV). Vagal inputs to the upper GI tract are cumbersome to measure non-invasively. Although cardiac and GI vagal outputs arise from distinct brainstem nuclei, the nucleus ambiguus, and the dorsal motor nucleus of the vagus, respectively, we aim to test the hypotheses that in freely moving rats HF-HRV power is correlated to proximal antral motility and can be altered by high levels of circulating estrogen and vagal-selective treatments known to affect antral motility.

METHODS

Male and female Sprague-Dawley rats were implanted with a miniaturized strain gauge on the proximal gastric antrum and ECG electrodes to collect simultaneous antral motility and electrocardiogram. After recovery, male rats underwent baseline recordings before and after administration of saline (N = 8), cholecystokinin (CCK; N = 7), ghrelin (N = 6), or food (N = 6). Female rats (N = 6) underwent twice-daily recordings to determine baseline correlations during estrous cycle stages.

KEY RESULTS

There was a significant positive correlation between HF-HRV and proximal antral motility at baseline in males and females with low, but not high, estrogen levels. In male rats, the significant positive correlation was maintained following CCK, but not ghrelin or food administration.

CONCLUSIONS AND INFERENCES

Our data suggest that in rodents, HF-HRV positively correlates to proximal antral motility at baseline conditions in males and low-estrogen females or following interventions, such as CCK, known to affect vagal tone. This correlation is not observed when antral motility is influenced by more complex events.

Myalgia and chronic fatigue syndrome following immunization: macrophagic myofasciitis and animal studies support linkage to aluminum adjuvant persistency and diffusion in the immune system

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a multifactorial and poorly undersood disabling disease. We present epidemiological, clinical and experimental evidence that ME/CFS constitutes a major type of adverse effect of vaccines, especially those containing poorly degradable particulate aluminum adjuvants. Evidence has emerged very slowly due to the multiplicity, lack of specificity, delayed onset, and frequent medical underestimation of ME/CFS symptoms. It was supported by an epidemiological study comparing vaccinated vs unvaccinated militaries that remained undeployed during Gulf War II. Affected patients suffer from cognitive dysfunction affecting attention, memory and inter-hemispheric connexions, well correlated to brain perfusion defects and associated with a stereotyped and distinctive pattern of cerebral glucose hypometabolism. Deltoid muscle biopsy performed to investigate myalgia typically yields macrophagic myofasciitis (MMF), a histological biomarker assessing longstanding persistency of aluminum agglomerates within innate immune cells at site of previous immunization. MMF is seemingly linked to altered mineral particle detoxification by the xeno/autophagy machinery. Comparing toxicology of different forms of aluminum and different types of exposure is misleading and inadequate and small animal experiments have turned old dogma upside down. Instead of being rapidly solubilized in the extracellular space, injected aluminum particles are quickly captured by immune cells and transported to distant organs and the brain where they elicit an inflammatory response and exert selective low dose long-term neurotoxicity. Clinical observations and experiments in sheep, a large animal like humans, confirmed both systemic diffusion and neurotoxic effects of aluminum adjuvants. Post-immunization ME/CFS represents the core manifestation of "autoimmune/inflammatory syndrome induced by adjuvants" (ASIA).

No moderating impact of a medically unexplained etiology on the relationship between psychological profile and chronic pain

OBJECTIVES

The objective of the present study was to test the moderating impact of an unknown pain etiology on the relationship between psychological factors and chronic pain intensity and disability.

METHODS

N = 471 chronic pain sufferers presented to an online Cognitive Behavioral Therapy randomized control trial, known as the Pain Course. Participants' etiology was classified as medically unexplained or medically explained via interview and self-reported data. Standardized psychological measures at baseline were used in a non-hierarchical cluster analysis, which allocated chronic pain participants into mutually exclusive groups.

RESULTS

Four distinct clusters were identified: Psychologically healthy, mild psychological distress, high psychological distress, and average. The profile with high psychological distress experienced the greatest pain intensity (mean: 6.44 (SD = 1.66)) and disability (mean: 17.53 (SD: 3.65)). This relationship was not moderated by preceding pain etiology being medically explained or unexplained (χ² (3) = 0.45, p = 0.93 and χ² (3) = 7.07, p = 0.07 respectively).

CONCLUSION

These findings indicate that an unknown pain etiology has little role in altering the relationship between psychological factors and pain disability in individuals experiencing chronic pain. This suggests that the psychological association with pain disability and intensity experienced by people with medically unexplained symptoms is similar to people with medically explained symptoms.

Antinuclear antibody and rheumatoid factor positivity in temporomandibular disorders

Background

To investigate the differences in clinical characteristics and long-term treatment outcomes according to antinuclear antibody(ANA) and rheumatoid factor(RF) positivity and the correlation between pain-related and hematological indices in temporomandibular disorders(TMD) patients.

Methods

Clinical examinations were done following the Research Diagnostic Criteria for TMD in 257 patients. Comprehensive screening along with psychological and hematological evaluations (ANA, RF, complete blood cell count, C-reactive protein[CRP] and erythrocyte sedimentation rate[ESR]) were conducted. Clinical characteristics and treatment outcomes were statistically compared between ANA/RF positive and negative groups.

Results

Thirty-nine patients showed ANA/RF positivity. Male patients had smaller comfortable mouth opening(CMO)(p = 0.033) and maximum mouth opening(MMO)(p = 0.016) ranges with more painful neck muscles on palpation when RF/ANA positive. Pain duration, intensity, disability days and psychological distress levels were also higher in RF/ANA positive male patients. Significant correlation was shown in ESR with pain duration(p < 0.05) and numeric rating scale(NRS) before treatment(p < 0.05), CRP with NRS before treatment(p < 0.01), and red blood cell (RBC) with pain intensity(p < 0.05), NRS before treatment(p < 0.01), CMO(p < 0.01), pain on palpation of cervical muscles(p < 0.01), CMO(p < 0.05), and MMO(p < 0.05) 6 months after treatment.

Conclusions

These results may point towards a nonspecific autoimmune disposition in a subgroup of TMD patients. RF and ANA could be considered as a screening test for the detection of autoimmune phenomena in TMD.

Insights into myalgic encephalomyelitis/chronic fatigue syndrome phenotypes through comprehensive metabolomics

The pathogenesis of ME/CFS, a disease characterized by fatigue, cognitive dysfunction, sleep disturbances, orthostatic intolerance, fever, irritable bowel syndrome (IBS), and lymphadenopathy, is poorly understood. We report biomarker discovery and topological analysis of plasma metabolomic, fecal bacterial metagenomic, and clinical data from 50 ME/CFS patients and 50 healthy controls. We confirm reports of altered plasma levels of choline, carnitine and complex lipid metabolites and demonstrate that patients with ME/CFS and IBS have increased plasma levels of ceramide. Integration of fecal metagenomic and plasma metabolomic data resulted in a stronger predictive model of ME/CFS (cross-validated AUC = 0.836) than either metagenomic (cross-validated AUC = 0.745) or metabolomic (cross-validated AUC = 0.820) analysis alone. Our findings may provide insights into the pathogenesis of ME/CFS and its subtypes and suggest pathways for the development of diagnostic and therapeutic strategies.

Prodrome and Non-prodrome Phenotypes of Bladder Pain Syndrome/Interstitial Cystitis

OBJECTIVE

To test the hypothesis that risk factors for bladder pain syndrome/interstitial cystitis (BPS/IC) in women differ between those with and without the BPS/IC prodrome.

MATERIALS AND METHODS

Incident cases of BPS/IC and healthy controls were recruited nationally. More than half the BPS/IC cases reported subsyndromal urinary symptoms for decades before onset of BPS/IC and were identified as having the prodrome. Risk factors for BPS/IC were examined separately for cases with and without the prodrome using a set of matched controls.

RESULTS

Two risk factors distinguished 178 prodrome from 134 non-prodrome cases. One was "UTIs" in the year before BPS/IC onset, possibly a manifestation of the prodrome itself. The other was the presence of the maximal number of nonbladder syndromes (NBSs): prodrome cases were 12 times more likely than non-prodrome cases to have ≥4 NBSs. Additional risk factors for prodrome and/or non-prodrome cases were the direct association of exogenous female hormones, as well as 3 inverse associations: type 2 diabetes mellitus, multiple pregnancies, and current daily smoking.

CONCLUSION

Prodrome cases developed urinary symptoms in their early 20s (ie, the prodrome) and were at very high risk of numerous NBSs. Non-prodrome cases developed urinary symptoms in their early 40s (ie, full-blown BPS/IC) and were no more likely than controls to have the maximal number of NBSs. These findings are consistent with recent suggestions of two BPS/IC phenotypes: one with systemic and psychosocial manifestations and the other more specific to the bladder. Additionally, several risk factors identified here might be hints of related or causal nervous system pathophysiologies.

Assemblages A and B of Giardia duodenalis reduce enteric glial cells in the small intestine in mice

Infection of Giardia duodenalis is one of the most common human parasitic disease worldwide. This infection may be related to important changes in the enteric nervous system. The objective of this study was to evaluate the myenteric and submucosal plexuses, the intestinal muscle layer, and gastrointestinal transit in mice infected with assemblages A and B of G. duodenalis. Swiss albino mice (Mus musculus) were infected with assemblages A and B of G. duodenalis for 15 days. Gastrointestinal transit time was evaluated before euthanasia. Duodenum and jejunum were removed for histological and immunohistochemical analyses. It was observed a reduction in the enteric glial cell count and a decrease in the ratio of enteric glial cells to neurons. The number of neurons did not change, but morphological changes were observed in the duodenum and jejunum in both plexuses, including an increase in the nuclear area and a reduction of cell bodies in the myenteric plexus and a decrease in the nuclear area in the submucosal plexus. A reduction of the thickness of the muscle layer was observed in the duodenum, with no significant differences in the gastrointestinal transit times. Assemblages A and B of G. duodenalis decrease the number of enteric glial cells in the myenteric and submucosal plexuses, decrease the thickness of the muscle layer, and change the morphology of neurons. Graphical abstract ᅟ.

Vagally mediated gastric effects of brain stem α2-adrenoceptor activation in stressed rats

Chronic stress exerts vagally dependent effects to disrupt gastric motility; previous studies have shown that, among other nuclei, A2 neurons are involved in mediating these effects. Several studies have also shown robust in vitro and in vivo effects of α2-adrenoceptor agonists on vagal motoneurons. We have demonstrated previously that brainstem vagal neurocircuits undergo remodeling following acute stress; however, the effects following brief periods of chronic stress have not been investigated. Our aim, therefore, was to test the hypothesis that different types of chronic stress influence gastric tone and motility by inducing plasticity in the response of vagal neurocircuits to α2-adrenoreceptor agonists. In rats that underwent 5 days of either homotypic or heterotypic stress loading, we applied the α2-adrenoceptor agonist, UK14304, either by in vitro brainstem perfusion to examine its ability to modulate GABAergic synaptic inputs to vagal motoneurons or in vivo brainstem microinjection to observe actions to modulate antral tone and motility. In neurons from naïve rats, GABAergic currents were unresponsive to exogenous application of UK14304. In contrast, GABAergic currents were inhibited by UK14304 in all neurons from homotypic and, in a subpopulation of neurons, heterotypic stressed rats. In control rats, UK14304 microinjection inhibited gastric tone and motility via withdrawal of vagal cholinergic tone; in heterotypic stressed rats, the larger inhibition of antrum tone was due to a concomitant activation of peripheral nonadrenergic, noncholinergic pathways. These data suggest that stress induces plasticity in brainstem vagal neurocircuits, leading to an upregulation of α2-mediated responses. NEW & NOTEWORTHY Catecholaminergic neurons of the A2 area play a relevant role in stress-related dysfunction of the gastric antrum. Brief periods of chronic stress load induce plastic changes in the actions of adrenoceptors on vagal brainstem neurocircuits.

Gastrointestinal and Hepatic Disease in Fibromyalgia

Fibromyalgia (FM) has historically been associated with several diseases in gastroenterology and hepatology. The most substantiated evidence pertains to irritable bowel syndrome (IBS). The pathogeneses of FM and IBS remain unclear, but it is likely related to dysregulation within the brain-gut axis, resulting in a hyperalgesic state. IBS and FM share other similarities, including a female predominance, fatigue, insomnia, and susceptibility to psychiatric state. These common manifestations and pathogeneses serve as a foundation for overlapping, multidisciplinary treatment modalities.

Amygdala-mediated mechanisms regulate visceral hypersensitivity in adult females following early life stress: importance of the glucocorticoid receptor and corticotropin-releasing factor

Alterations in amygdala activity are apparent in women who report a history of early life stress (ELS) and those diagnosed with chronic pain disorders. Chronic stress in adulthood induces visceral hypersensitivity by alterations in glucocorticoid receptor (GR) and corticotropin-releasing factor (CRF) expression within the central amygdala (CeA). Here, we hypothesized that unpredictable ELS, previously shown to induce visceral hypersensitivity in adult female rats, alters GR and CRF expression in the CeA. After neonatal ELS, visceral sensitivity and GR and CRF gene expression were quantified in adult female rats. After unpredictable ELS, adult female rats exhibited visceral hypersensitivity and increased expression of GR and CRF in the CeA. After predictable ELS, adult female rats demonstrated normosensitive behavioral pain responses and upregulation of GR but not CRF in the CeA. After the ELS paradigms, visceral sensitivity and gene expression within the CeA were unaffected in adult male rats. The role of GR and CRF in modulating visceral sensitivity in adult female rats after ELS was investigated using oligodeoxynucleotide sequences targeted to the CeA for knockdown of GR or CRF. Knockdown of GR increased visceral sensitivity in all rats but revealed an exaggerated visceral hypersensitivity in females with a history of predictable or unpredictable ELS compared with that of controls. Knockdown of CRF expression or antagonism of CRF1R in the CeA attenuated visceral hypersensitivity after unpredictable ELS. This study highlights a shift in GR and CRF regulation within the CeA after ELS that underlies the development of visceral hypersensitivity in adulthood.

Nationwide Multicenter Study for Overlaps of Common Functional Gastrointestinal Disorders in Korean Patients With Constipation

Background/Aims

In spite of increased concerns about the overlaps among the various functional gastrointestinal disorders (FGIDs), studies for the overlap between constipation and other common FGIDs are rare. Therefore, we investigated the patterns of overlaps between constipation and other common FGIDs.

Methods

This study was designed as a prospective nationwide multi-center questionnaire study using Rome III questionnaires for functional dyspepsia (FD), irritable bowel syndrome (IBS), and functional constipation (FC), as well as various questionnaires about patients' information, degree of symptoms, and quality of life. For the evaluation of gastroesophageal reflux disease (GERD), GERD-Q was used.

Results

From 19 centers, 759 patients with constipation were enrolled. The proportions of FC and IBS subtypes of constipation (IBS-C) were 59.4% and 40.6%, respectively. Among them, 492 (64.8%) showed no overlap. One hundred and thirty-six patients (17.9%) presented overlapping GERD, and 80 patients (10.5%) presented overlapping FD. Fifty one (6.7%) of patients were overlapped by both GERD and FD. Coincidental herniated nucleus pulposus (HNP) (P = 0.026) or pulmonary diseases (P = 0.034), reduced fiber intake (P = 0.013), and laxative use (P < 0.001) independently affected the rate of overlaps. These overlapping conditions negatively affected the constipation-associated quality of life, general quality of life, and degree of constipation.

Conclusions

The overlap of GERD or FD was common in patients with constipation. Coincidental HNP or pulmonary diseases, reduced fiber intake, and laxatives use were found to be independent associated factors for overlapping common FGIDs in Korean patients with constipation.

The management of functional dyspepsia in clinical practice: what lessons can be learnt from recent literature?

Functional dyspepsia is a prevalent functional gastrointestinal disorder that can significantly erode the quality of life of sufferers and places a major cost burden on healthcare services. In this article, we review the recent literature, selecting the information we consider relevant since it has changed our clinical management of patients with functional dyspepsia.

Multiple functional gastrointestinal disorders linked to gastroesophageal reflux and somatization: A population-based study

BACKGROUND

It is unknown why functional gastrointestinal disorders (FGIDs) overlap and limited information exists on risk factors for those with overlap. Our aim was to estimate the prevalence of combinations of FGIDs including reflux (FGIDs-gastroesophageal reflux [GER]), and evaluate potential risk factors for people with multiple disorders in a representative US community.

METHODS

A population-based study was conducted by mailing a valid GI symptom questionnaire to an age- and gender-stratified random sample of residents of Olmsted County, MN. Rome III definitions were used to identify people with FGIDs, and GER was defined by weekly or more frequent heartburn or acid regurgitation. The prevalence of people meeting multiple symptom complexes was estimated. Moreover, potential risk factors for people with multiple disorders were evaluated.

KEY RESULTS

A total of 3548 people provided data for each of the necessary symptom questions (mean age: 61±16 years, 54% female). Among these 3548 subjects, 2009 (57%) had no FGIDs-GER, 906 (26%) had a pure FGID-GER, 372 (10%) had 2 FGIDs-GER, and 261 (7%) had 3 or more FGIDs-GER. Somatization as assessed by a higher Somatic Symptom Checklist score (OR=3.3, 95% CI [2.7,4.1]) was associated with an increased odds for those with 3 or more FGIDs-GER compared to subjects with a pure FGID-GER adjusting for age and gender.

CONCLUSIONS AND INFERENCES

Symptom complex overlap is common rather than rare in the community. GER is an integral symptom complex associated with both upper and lower FGIDs. Somatization is a strong risk factor for multiple FGIDs.

High risk of lower urinary tract symptoms in patients with irritable bowel syndrome

BACKGROUND

The aim of the present study was to investigate the prevalence of urinary tract infection (UTI) and the risk of lower urinary tract symptoms (LUTS) in women with irritable bowel syndrome (IBS) (including each subtype: constipation, diarrhea, and mixed) compared to women in the general population.

METHODS

Between January 2014 and December 2015, consecutive adult female patients diagnosed with IBS at the outpatient clinic of the University of Salerno and healthy women with regular bowel habits were enrolled in the study. At baseline, we checked for UTI with a dipstick test and questioned patients about the presence of LUTS in the previous 24 h.

RESULTS

We enrolled 141 IBS patients and 91 healthy controls in the study. There was no difference in the prevalence of UTI between IBS patients and healthy controls (4.9 vs 3.3%, p = 0.5). When we excluded patients with UTI, we found a 2.79 higher risk of increased urinary frequency [odds ratio (OR) 2.79, 95% confidence interval (CI) 1.37-5.68], a 2.68 higher risk of urinary urgency (OR 2.68, 95% CI 1.04-6.91), and more than three times the risk of having dysuria (OR 3.25, 95% CI 1.06-9.97) in IBS women compared to healthy controls. The risk of having at least one urinary symptom was independent of IBS subtype and IBS severity.

CONCLUSIONS

Our study shows that IBS women have a similar risk of UTI compared to healthy women even if they complain more of LUTS, independently of IBS subtype and severity.

Central Neuromodulators for Treating Functional GI Disorders: A Primer

Patients with functional GI disorders (FGIDs) are commonplace in the gastroenterologist's practice. A number of these patients may be refractory to peripherally acting agents, yet respond to central neuromodulators. There are benefits and potential adverse effects to using TCAs, SSRIs, SNRIs, atypical antipsychotics, and miscellaneous central neuromodulators in these patients. These agents can benefit mood, pain, diarrhea, constipation, nausea, sleep, and depression. The mechanisms by which they work, the differences between classes and individual agents, and the various adverse effects are outlined. Dosing, augmentation strategies, and treatment scenarios specifically for painful FGIDs, FD with PDS, and chronic nausea and vomiting syndrome are outlined.

Fecal metagenomic profiles in subgroups of patients with myalgic encephalomyelitis/chronic fatigue syndrome

BACKGROUND

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is characterized by unexplained persistent fatigue, commonly accompanied by cognitive dysfunction, sleeping disturbances, orthostatic intolerance, fever, lymphadenopathy, and irritable bowel syndrome (IBS). The extent to which the gastrointestinal microbiome and peripheral inflammation are associated with ME/CFS remains unclear. We pursued rigorous clinical characterization, fecal bacterial metagenomics, and plasma immune molecule analyses in 50 ME/CFS patients and 50 healthy controls frequency-matched for age, sex, race/ethnicity, geographic site, and season of sampling.

RESULTS

Topological analysis revealed associations between IBS co-morbidity, body mass index, fecal bacterial composition, and bacterial metabolic pathways but not plasma immune molecules. IBS co-morbidity was the strongest driving factor in the separation of topological networks based on bacterial profiles and metabolic pathways. Predictive selection models based on bacterial profiles supported findings from topological analyses indicating that ME/CFS subgroups, defined by IBS status, could be distinguished from control subjects with high predictive accuracy. Bacterial taxa predictive of ME/CFS patients with IBS were distinct from taxa associated with ME/CFS patients without IBS. Increased abundance of unclassified Alistipes and decreased Faecalibacterium emerged as the top biomarkers of ME/CFS with IBS; while increased unclassified Bacteroides abundance and decreased Bacteroides vulgatus were the top biomarkers of ME/CFS without IBS. Despite findings of differences in bacterial taxa and metabolic pathways defining ME/CFS subgroups, decreased metabolic pathways associated with unsaturated fatty acid biosynthesis and increased atrazine degradation pathways were independent of IBS co-morbidity. Increased vitamin B6 biosynthesis/salvage and pyrimidine ribonucleoside degradation were the top metabolic pathways in ME/CFS without IBS as well as in the total ME/CFS cohort. In ME/CFS subgroups, symptom severity measures including pain, fatigue, and reduced motivation were correlated with the abundance of distinct bacterial taxa and metabolic pathways.

CONCLUSIONS

Independent of IBS, ME/CFS is associated with dysbiosis and distinct bacterial metabolic disturbances that may influence disease severity. However, our findings indicate that dysbiotic features that are uniquely ME/CFS-associated may be masked by disturbances arising from the high prevalence of IBS co-morbidity in ME/CFS. These insights may enable more accurate diagnosis and lead to insights that inform the development of specific therapeutic strategies in ME/CFS subgroups.

Current and emergent pharmacologic treatments for irritable bowel syndrome with diarrhea: evidence-based treatment in practice

Irritable bowel syndrome with diarrhea (IBS-D) is a common, chronic functional gastrointestinal disorder with symptoms that can be distressing for patients and often result in substantially impaired quality of life. This review focuses on providing clinicians with information on practical, evidence-based treatment for IBS-D. Current therapies commonly used for the treatment of IBS-D, including pharmacologic and nonpharmacologic interventions, are briefly reviewed, followed by discussion of the emergent pharmacologic treatments (rifaximin and eluxadoline) and medical foods (IBgard® and EnteraGam®). Given the lack of a standard treatment algorithm for IBS-D and the emergence of new pharmacologic therapies, treatment needs to be tailored to the individual patient and take into account the severity of disease. In this context, the latter part of this manuscript examines how treatments for IBS-D can be used in clinical practice by presenting three patient case scenarios with varying degrees of IBS-D severity. For each case, the patient's medical history and clinical presentation are related to the Rome Foundation multidimensional clinical profile (MDCP) and potential treatment options with current and emergent therapies are reviewed. The interplay of gastrointestinal symptoms and their psychosocial impact, as well as the importance of a patient-centered approach to therapy, are discussed. Consideration is given to the potential need for combination therapies and how emergent treatments could fit into the treatment pathway for mild, moderate, and severe cases of IBS-D in clinical practice.

Symptoms and the body: Taking the inferential leap

The relationship between the conscious experience of physical symptoms and indicators of objective physiological dysfunction is highly variable and depends on characteristics of the person, the context and their interaction. This relationship often breaks down entirely in the case of "medically unexplained" or functional somatic symptoms, violating the basic assumption in medicine that physical symptoms have physiological causes. In this paper, we describe the prevailing theoretical approach to this problem and review the evidence pertaining to it. We then use the framework of predictive coding to propose a new and more comprehensive model of the body-symptom relationship that integrates existing concepts within a unifying framework that addresses many of the shortcomings of current theory. We describe the conditions under which a close correspondence between the experience of symptoms and objective physiology might be expected, and when they are likely to diverge. We conclude by exploring some theoretical and clinical implications of this new account.

Psychological factors influence the overlap syndrome in functional gastrointestinal disorders (FGIDs) among middle-aged women in South Korea

This study investigated the psychological factors related to the overlap syndrome, i.e., multiple gastrointestinal conditions that are part of functional gastrointestinal disorders (FGIDs) in the same individual and potentially related to quality of life (QOL) among women aged 45-60 years (n = 627) in South Korea. The study was undertaken between July 2014 and March 2015. Depressive and anxiety symptoms were ascertained using the Center for Epidemiologic Studies Depression scale (CES-D) and the Beck Anxiety Inventory (BAI), respectively. Negative cognition and the cognitive triad were identified using the Automatic Thoughts Questionnaire-Negative (ATQ-N) and the Cognitive Triad Inventory (CTI), respectively. Resilience and QOL were assessed using the Connor-Davidson Resilience Scale (CD-RISC) and World Health Organization Quality of Life scale abbreviated version (WHOQOL-BREF). Women with the overlap syndrome had the highest CES-D (mean = 16.66 ± 11.79, p < .001), BAI (mean = 17.46 ± 12.67, p < .001), and ATQ-N scores (mean = 53.61 ± 20.88, p < .001), followed by women with gastrointestinal disorders but without the overlap syndrome and healthy controls. Healthy controls had the highest WHOQOL-BREF score (mean = 77.69 ± 12.53, p < .001). After stepwise selection, the final model explained 61.8 percent of the variance in QOL. Thus, depressive symptoms, anxiety, negative cognition, cognitive triad, and resilience were significantly related to QOL in women with the overlap syndrome.

Functional urological disorders: a sensitized defence response in the bladder-gut-brain axis

Functional urological and gastrointestinal disorders are interrelated and characterized by a chronic course and considerable treatment resistance. Urological disorders associated with a sizeable functional effect include overactive bladder (OAB), interstitial cystitis/bladder pain syndrome (IC/BPS), and chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Poor treatment outcomes might be attributable to untreated underlying psychological and psychiatric disorders, as the co-occurrence of functional urological and gastrointestinal disorders with mood and anxiety disorders is common. The hypothetical bladder-gut-brain axis (BGBA) is a useful framework under which this interaction can be studied, suggesting that functional disorders represent a sensitized response to earlier threats such as childhood adversity or previous traumatic events, resulting in perceived emotional and bodily distress - the symptoms of functional disorders. Psychological and physical stress pathways might contribute to such alarm falsification, and neuroticism could be a risk factor for the co-occurrence of functional disorders and affective conditions. Additionally, physical threat - either from external sources or internal sources such as infection - might contribute to alarm falsification by influencing body-brain crosstalk on homeostasis and, therefore, affecting mood, cognition, and behaviour. Multidisciplinary research and an integrated care approach is, therefore, required to further elucidate and remediate functional urological and gastrointestinal polymorphic phenotypes.