Post-Infectious Irritable Bowel Syndrome, an Inflammation-Immunological Model with Relevance for Other IBS and Functional Dyspepsia

Unmet needs of drugs for irritable bowel syndrome and inflammatory bowel diseases: interest of vagus nerve stimulation and hypnosis

The gut and the brain communicate bidirectionally through the autonomic nervous system. The vagus nerve is a key component of this gut-brain axis, and has numerous properties such as anti-inflammatory, antinociceptive, anti-depressive effects. A perturbation of this gut-brain communication is involved in the pathogeny of functional digestive disorders, such as irritable bowel syndrome, and inflammatory bowel diseases. Stress plays a role in the pathogeny of these diseases, which are biopsychosocial models. There are presently unmet needs of pharmacological treatments of these chronic debilitating diseases. Treatments are not devoid of side effects, cost-effective, do not cure the diseases, can lose effects over time, thus explaining the poor satisfaction of patients, their lack of compliance, and their interest for non-drug therapies. The gut-brain axis can be targeted for therapeutic purposes in irritable bowel syndrome and inflammatory bowel disease through non-drug therapies, such as hypnosis and vagus nerve stimulation, opening up possibilities for responding to patient expectations.

Postinfection Irritable Bowel Syndrome Following Clostridioides difficile Infection: A Systematic-review and Meta-analysis

BACKGROUND

Postinfection irritable bowel syndrome (PI-IBS) affects ~14% patients after acute bacterial enterocolitis.

AIM

The aim of this study was to conduct a systematic review and meta-analysis to find the prevalence of PI-IBS following Clostridioides difficile infection (CDI).

METHODS

We systematically searched Medline, Embase, and Web of Science from inception through January 20, 2020 for cohort studies assessing PI-IBS following CDI. Primary outcome was pooled prevalence calculated using inverse variance heterogeneity model [MetaXL (v. 5.3)]. A priori subgroup analyses were done [by irritable bowel syndrome (IBS) diagnostic criteria-Rome vs. others, time of IBS diagnosis-<6 or >6 mo, exclusion or inclusion of pre-existing IBS and CDI treatment-antibiotic with fecal microbiota transplantation vs. antibiotic only]. Heterogeneity was considered substantial if I2>50%.

RESULTS

From 2007 to 2019, 15 studies were included (10 prospective, 5 retrospective; 9 full-text, 6 abstracts). Data from 1218 patients were included in the quantitative analysis. Risk of bias was low in 7, medium in 4 and high in 4 studies. Pooled prevalence of PI-IBS was 21.1% (95% confidence interval, 8.2%-35.7%), I2=96%. Common PI-IBS subtypes were diarrhea-predominant in 46.3% (50) patients, and mixed in 33.3% (36) patients. Subgroup analyses by IBS diagnostic criteria, time of IBS diagnosis or CDI treatment did not significantly change the primary outcome (all P>0.05), nor decrease heterogeneity. Funnel plot analysis revealed publication bias.

CONCLUSIONS

Over 20% of patients develop PI-IBS after CDI. Factors such as diagnostic criteria for IBS and CDI treatment did not affect prevalence, though small numbers limit the confidence in these conclusions. Larger, well conducted studies are needed to study PI-IBS in CDI.

Circulating Anti-cytolethal Distending Toxin B and Anti-vinculin Antibodies as Biomarkers in Community and Healthcare Populations With Functional Dyspepsia and Irritable Bowel Syndrome

OBJECTIVES

Anti-cytolethal distending toxin B (CdtB) and anti-vinculin antibodies have been proposed as biomarkers that discriminate irritable bowel syndrome (IBS) diarrhea from inflammatory bowel disease; however, it is unknown whether they can also discriminate patients with IBS and IBS subtypes and functional dyspepsia (FD) from healthy individuals in the general population. We aimed to determine whether anti-CdtB and anti-vinculin can discriminate IBS and FD from health and from organic gastrointestinal (GI) disease.

METHODS

Adults were enrolled from 2 Australian studies: (i) a random, population-based study (n = 331) with subjects diagnosed with IBS (n = 63) or FD (n = 61) by modified Rome III criteria or healthy control subjects (n = 246) who did not meet criteria for IBS and/or FD and (ii) an outpatient-based study with subjects diagnosed with IBS (n = 256) and/or FD (n = 55) or organic GI disease (n = 182) by an independent clinician. Serum levels of anti-CdtB/anti-vinculin antibodies were determined by enzyme-linked immunosorbent assay.

RESULTS

There was a significantly higher mean value of anti-CdtB in FD vs healthy controls (mean = 2.46 [SD = 0.72] vs mean = 2.14 [SD = 0.77]; P = 0.005) and IBS/FD overlap vs healthy controls (mean = 2.47 [SD = 0.78] vs mean = 2.14 [SD = 0.77]; P = 0.02). There were no significant differences in anti-CdtB in IBS and FD outpatients or IBS/FD subgroups compared with patients with organic GI disease. In terms of anti-vinculin, there were no significant differences between IBS and FD and healthy controls or between IBS and FD and organic GI disease controls.

DISCUSSION

We did not confirm that anti-CdtB/anti-vinculin discriminated IBS diarrhea from organic GI disease in Australian subjects. However, we did find higher anti-CdtB in FD and IBS/FD overlap vs healthy controls. Postinfectious FD may be more common than currently recognized.

Comorbidities of Patients with Functional Somatic Syndromes Before, During and After First Diagnosis: A Population-based Study using Bavarian Routine Data

Functional somatic syndromes (FSS) are characterised by the presence of one or multiple chronic symptoms that cannot be attributed to a known somatic disease. They are thought to arise though a complex interaction of biological and psychosocial factors, but it is unclear whether they share a common aetiology. One hypothesis supported by recent studies is that the FSS are postinfectious disorders, as is widely recognised for a subset of patients with irritable bowel syndrome. Our study used claims data submitted by office-based physicians to compare groups of patients with different FSS in the five years before and after the point of first diagnosis. Even five years prior to diagnosis, FSS patients consulted more frequently for a range of psychological and somatic conditions than did controls. Following diagnosis, consultation rates increased further and remained persistently high. Five years after diagnosis, between 34% (somatization disorder) and 66% (fibromyalgia) of patients were still being treated for the condition. Both prior gastrointestinal and upper-respiratory infection were associated with an increased risk of developing an FSS. We therefore recommend that patients at risk should be identified at an early stage and the underlying psychosocial and somatic issues addressed to prevent progression of the condition.

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.

Alleviation of Irritable Bowel Syndrome-Like Symptoms and Control of Gut and Brain Responses with Oral Administration of Dolichos lablab L. in a Mouse Model

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder manifesting as unexplained abdominal pain and bowel habit changes. The pathogenesis of post-infectious IBS is associated with gut–brain axis dysfunction, including low-grade colonic inflammation and anxiety-related long-term brain changes. This study analyzed the efficacy of a standardized extract of Dolichos lablab L. extract (DL), a bean species, in an IBS mouse model resembling post-infectious, diarrhea-dominant IBS. Using a zymosan-induced animal IBS model, we found that oral administration of DL significantly attenuated zymosan-induced increases in colonic macroscopic scores and minimized weight loss without affecting food intake. In the DL-treated mice, the mast cell count and tumor necrosis factor-α level in the colon markedly decreased, similar to results in sulfasalazine-treated mice and in mice with lipopolysaccharide-stimulated bone marrow-derived mast cells. The number of visceral pain-related behaviors was much lower in the DL-treated mice. Anxiety-like behaviors significantly improved, comparable to that after treatment with amitriptyline. The c-Fos expression level in the prefrontal cortex was significantly reduced. Our data suggest that DL could be beneficial for treating IBS by acting on the gut and brain.

Incidence of irritable bowel syndrome and chronic fatigue following GI infection: a population-level study using routinely collected claims data

OBJECTIVES

To investigate the occurrence of postinfectious IBS in routine outpatient care, comparing different types of GI infection and its interaction with psychosomatic comorbidity.

DESIGN

Retrospective cohort study using routinely collected claims data covering statutorily insured patients in Bavaria, Germany. Cases were defined as patients without prior record of functional intestinal disorder with a first-time diagnosis of GI infection between January 2005 and December 2013 and classed according to the type of infection. Each case was matched by age, sex and district of residence to a patient without history of GI infection. Prior psychological disorder (depression, anxiety or stress reaction disorder) was assessed in the 2 years prior to inclusion. Proportional hazards regression models were used to estimate the HRs for GI infection and psychological disorder. Chronic fatigue syndrome (CFS) was assessed as a comparator outcome.

RESULTS

A total of 508 278 patients with first diagnosis of GI infection were identified, resulting in a matched cohort of 1 016 556 patients. All infection types were associated with an increased risk of IBS (HR: 2.19-4.25) and CFS (HR 1.35-1.82). Prior psychological disorder was a distinct risk factor for IBS (HR: 1.73) and CFS (HR: 2.08). Female sex was a further risk factor for both conditions.

CONCLUSION

Psychological disorder and GI infections are distinct risk factors for IBS. The high incidence of non-specific GI infection suggests that postinfectious IBS is a common clinical occurrence in primary care. Chronic fatigue is a further significant sequela of GI infection.

A randomized placebo-controlled clinical trial of a multi-strain probiotic formulation (Bio-Kult®) in the management of diarrhea-predominant irritable bowel syndrome

Background

Accumulating evidence supports the view that an imbalance of gut bacteria contributes to IBS, and that increasing the mass of beneficial species may reduce the numbers of pathogenic bacteria and help alleviate symptoms.

Methods

In this double-blind trial 400 adult patients with moderate-to-severe symptomatic diarrhea-predominant IBS (IBS-D) were randomized to treatment with the multi-strain probiotic Bio-Kult® (14 different bacterial strains) or placebo for 16 weeks. The change in severity and frequency of abdominal pain was the primary outcome measure.

Results

Probiotic treatment significantly improved the severity of abdominal pain in patients with IBS-D. A 69% reduction for probiotic versus 47% for placebo (p < 0.001) equates to a 145 point reduction on the IBS-severity scoring system (IBS-SSS). The proportion of patients who rated their symptoms as moderate-to-severe was reduced from 100% at baseline to 14% for the multi-strain probiotic at follow-up (month 5) versus 48% for placebo (p < 0.001). Also, the number of bowel motions per day from month 2 onwards was significantly reduced in the probiotic group compared with the placebo group (p < 0.05). In addition to relieving symptoms, the probiotic markedly improved all dimensions of quality of life in the 34-item IBS-Quality of Life (IBS-QoL) questionnaire. No serious adverse events were reported.

Conclusions

The multi-strain probiotic was associated with significant improvement in symptoms in patients with IBS-D and was well-tolerated. These results suggest that probiotics confer a benefit in IBS-D patients which deserves further investigation.

Trial registration

[Clinicaltrials.gov NCT03251625; retrospectively registered on August 9, 2017].

Electronic supplementary material

The online version of this article (doi:10.1186/s12876-018-0788-9) contains supplementary material, which is available to authorized users.

Prevalence and risk factors for functional bowel disorders in South China: a population based study using the Rome III criteria

BACKGROUND

Functional bowel disorders (FBDs) such as irritable bowel syndrome (IBS) impact on quality of life and health care resources. It is uncertain whether patients with functional digestive symptoms have similar characteristics in different populations. This population-based study assessed the prevalence and identified risk factors for these disorders in South-East China.

METHODS

Five communities were selected at random and invitations distributed to a representative sample (block randomization). Questionnaires were completely supervised by investigators. Demographic and medical data with FBD symptoms (Rome III criteria), psychological condition, life event stress, and quality of life were collected.

KEY RESULTS

Functional bowel disorder prevalence was 41.6% in 1999/2115 (94.5%) completed questionnaires: 9.9% functional constipation (FC), 6.8% bloating (FB), 6.5% diarrhea (FD), 5.9% IBS (IBS-D 47.1%, IBS-M 23.9%, IBS-C 12.8%, IBS-U 16.2%), and 12.6% unspecified. Similar numbers of men and women had FBDs or IBS (overall; 51.3% male vs 48.7% female, P=.796); however, there was female predominance in FC (62.1%, P<.001) and FB (58.5%, P=.038). FBDs were associated with greater anxiety, depression, life event stress, and a lower quality of life compared with those without symptoms (all, P<.0001). Logistic regression identified medical co-morbidity, anxiety/depression, and life event stress as independent risk factors for these disorders.

CONCLUSIONS & INFERENCES

Functional bowel disorders are as common in South China as in western populations. A similar number of men and women report FBDs and IBS. Only FC and FB are more prevalent in females. Independent risk factors associated with FBDs included physical and psychosocial stressors.

Long-term Clinical Course of Post-infectious Irritable Bowel Syndrome After Shigellosis: A 10-year Follow-up Study

Background/Aims

A limited number of studies are available regarding the long-term natural history of post-infectious irritable bowel syndrome (PI-IBS). We aimed to investigate the long-term clinical course of PI-IBS.

Methods

A prospective cohort study was conducted from a 2001 shigellosis outbreak in a Korean hospital with about 2000 employees. A cohort of 124 hospital employees who were infected by Shigella sonnei due to contaminated food in the cafeteria, and 105 sex- and age-matched, non-infected, controls were serially followed for their bowel symptoms by questionnaire surveys for 10 years.

Results

The Shigella-infected cohort showed significantly higher odds ratio for irritable bowel syndrome (IBS) at 1-year (11.90; 95% CI, 1.49–95.58) and 3-year (3.93; 95% CI, 1.20–12.86) follow-up, compared to their controls. However, corresponding odds ratio for PI-IBS was not significantly increased at 5-year (1.88; 95% CI, 0.64–5.54) and 8-year (1.87; 95% CI, 0.62–5.19) follow-up. At 10-year follow-up survey, the prevalence of IBS was similar for the Shigella-infected cohort and their controls (23.3% versus 19.7%, P = 0.703). Risk factors which were independently associated with PI-IBS among the Shigella-infected cohort included younger age, previous history of functional bowel disorder, and longer duration of diarrhea at baseline.

Conclusions

Patients who were infected by Shigella sonnei experienced significantly increased risk of IBS until 3 years after shigellosis, and modestly increased risk until 8 years, but showed similar risk of IBS with uninfected controls at 10 years post-infection. PI-IBS is quite a chronic disorder, and follows a long-term natural course.

Functional dyspepsia and dyspepsia associated with Helicobacter pylori infection: Do they have different clinical characteristics?

BACKGROUND

Helicobacter pylori causes motor, secretory, and inflammatory gastrointestinal disorders and therefore the term "functional" has been questioned when referring to dyspepsia associated with this bacterium. Patients with dyspepsia and Helicobacter pylori infection could have clinical characteristics that differentiate them a priori from those with true functional dyspepsia.

AIMS

To determine whether there are clinical differences between patients with functional dyspepsia and Helicobacter pylori-associated dyspepsia that enable their a priori identification and to know the prevalence of Helicobacter pylori infection in patients with functional dyspepsia.

PATIENTS AND METHODS

A total of 578 patients with dyspepsia with no significant lesions detectable through endoscopy were divided into 2 groups according to the presence of Helicobacter pylori. The clinical characteristics, medical history, comorbidities, and use of health resources were compared between the two groups. A sub-analysis pairing the groups by age and sex in a 1:1 ratio was carried out to reduce bias.

RESULTS

A total of 336 patients infected with Helicobacter pylori were compared with 242 non-infected patients. The prevalence of infection in the patients with dyspeptic symptoms and no endoscopically detectable lesions was 58%. The initial analysis showed that the cases with dyspepsia and Helicobacter pylori infection were more frequently associated with overweight, obesity, high blood pressure, diabetes mellitus, and metabolic syndrome, but the paired analysis nullified all these differences.

CONCLUSIONS

The patients with dyspepsia infected with Helicobacter pylori had similar clinical characteristics to the non-infected patients and could not be differentiated a priori. The prevalence of Helicobacter pylori infection in patients with functional dyspepsia was 58% and increased with age.

Post-infectious and non post-infectious irritable bowel syndrome: A comparative study

Objective:

To compare the post-infectious irritable bowel syndrome (PI-IBS) and none post-infectious irritable bowel syndrome (NPI-IBS) clinically and experimentally.

Methods:

From May 2013 to January 2015, eighty-nine patients with irritable bowel syndrome (IBS)were recruited in the internal department of the affiliated hospital of Shandong University of Traditional Chinese Medicine. The clinical data were collected for all the patients, and a blood sample was collected to detect the level of C-reactive protein (CRP) and intestinal fatty acid binding protein (IFABP), an investigation questionnaire of gastrointestinal symptom rating scale (GSRS) and self-rating anxiety scale (SAS) were carried out to evaluate the gastrointestinal function and anxiety status.

Results:

In the study, forty-eight patients were included in PI-IBS group and 41 in Non-PI-IBS group. There was no significant difference in age, gender and GSRS between the two groups (p>0.05). In PI-IBS group 70.8% patients presented with the primary symptom of diarrhea and 60.4% presented with a SAS scores over 50, but in Non-PI-IBS group, the values were only 19% (p<0.05) and 34.1% (p<0.05). The level of IFABP and CRP were significantly higher in PI-IBS group than those in Non-PI-IBS group (p<0.05).

Conclusion:

The PI-IBS may be different from Non-PI-IBS in mechanism and should be treated using different strategies.

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.

Effectiveness of osteopathic manipulative therapy for managing symptoms of irritable bowel syndrome: a systematic review

CONTEXT

Irritable bowel syndrome (IBS) is a common and often lifelong functional gastrointestinal disorder. There is a scarcity of effective management options for IBS.

OBJECTIVE

To assess the effectiveness of osteopathic manipulative therapy (OMTh) for managing the symptoms of IBS.

DATA SOURCES

Articles without language or publication-date restriction were searched in PubMed, Embase, Cochrane Library, PEDro, OSTMED.DR, and Osteopathic Research Web. Search terms included irritable bowel syndrome, IBS, functional colonic disease, colon irritable, osteopath*, osteopathic manipulation, osteopathic medicine, clinical trial, and randomized clinical trial. Experts in the field of visceral osteopathy were also contacted to identify additional studies.

STUDY SELECTION

The authors evaluated randomized controlled trials (RCTs) of OMTh for IBS in adults in whom IBS was diagnosed using Rome (I-III) criteria. If OMTh was not the sole intervention in the intervention group and if the same additional interventions were not applied to the control group, the study was excluded.

DATA EXTRACTION

Citation identification, study selection, and data extraction were independently undertaken by 2 reviewers with a data extraction form from the Cochrane Collaboration. A consensus method was used to resolve disagreements concerning the assessment of the methodologic quality of the RCTs that were reviewed.

RESULTS

The search identified 10 studies that examined OMTh for patients with IBS; 5 studies (204 patients) met the inclusion criteria. All studies were assessed as having low risk of bias according to the Cochrane Collaboration criteria, although there was heterogeneity in the outcome measures and control interventions. Three studies used visual analog scales for abdominal pain, whereas others used the IBS severity score and the Functional Bowel Disorder Severity Index. A variety of secondary outcomes were used. All studies reported more pronounced short-term improvements with OMTh compared with sham therapy or standard care only. These differences remained statistically significant after variable lengths of follow-up in 3 studies.

CONCLUSION

The present systematic review provides preliminary evidence that OMTh may be beneficial in the treatment of patients with IBS. However, caution is required in the interpretation of these findings because of the limited number of studies available and the small sample sizes.

Mast Cell-dependent Mesenteric Afferent Activation by Mucosal Supernatant From Different Bowel Segments of Guinea Pigs With Post-infectious Irritable Bowel Syndrome

Background/Aims

Mesenteric afferent nerves (MANs) play a pivotal role in the visceral-nociceptive perception. Inappropriate activation of MANs may be involved in the pathogenesis of post-infectious irritable bowel syndrome (PI-IBS). However, the underlying mechanisms remain unclear. We assessed the effects of mucosal mediators from different bowel segments of guinea pigs with PI-IBS on MAN firing and the role of mast cells.

Methods

PI-IBS was induced in guinea pigs by Trichinella spiralis infection. Inflammation in terminal ileum, proximal and distal colon was scored with hematoxylin-eosin staining, and mast cell infiltration was assessed with immunofluorescence. We determined the effects of supernatant extracted from the mucosa of different bowel segments of PI-IBS on MANs activity, and assessed the role of mast cells in this process.

Results

Eight weeks after infection, intestinal inflammation resolved, whereas mast cell numbers increased significantly in terminal ileum and proximal colon (P < 0.05) compared with findings in controls. Mucosal supernatant from different bowel segments of PI-IBS models, but not from controls, significantly enhanced the frequency of MAN firing (terminal ileum 41.01 ± 7.60 Hz vs. 26.55 ± 0.67 Hz, P = 0.001; proximal colon 45.90 ± 11.20 Hz vs. 30.88 ± 6.92 Hz, P = 0.002; distal colon 48.25 ± 9.70 Hz vs. 29.47 ± 6.13 Hz, P < 0.001). In addition, the excitatory effects were inhibited by mast cell stabilizer Nasmil (terminal ileum, 32.71 ± 2.52 Hz, P = 0.030; proximal colon, 30.94 ± 4.44 Hz, P = 0.002; distal colon, 27.15 ± 5.83 Hz, P < 0.001).

Conclusions

Supernatant from the intestinal mucosa of different bowel segments of PI-IBS models markedly enhanced the MAN firing in a mast cell-dependent manner, indicating that mast cell-mediated MAN activation plays an important role in the pathogenesis of PI-IBS.

Associations between IL-1RA polymorphisms and small intestinal bacterial overgrowth among patients with irritable bowel syndrome from India

BACKGROUND

Low-grade inflammation (controlled by pro and anti-inflammatory molecules), induced by gut microbes in patients with small intestinal bacterial overgrowth (SIBO), may be associated with irritable bowel syndrome (IBS). Polymorphisms of IL-RA gene (anti-inflammatory) was evaluated in IBS and healthy subjects (HS); small intestinal mucosal IL-1α and β levels (pro-inflammatory) in relation to the presence of SIBO were evaluated in a subset of patients.

METHODS

Two hundred and twenty-one IBS patients and 273 age- and gender-matched HS were included. Exactly 209 of 221 patients (Rome III) and 273 HS were genotyped (PCR) for IL-1RA polymorphism. Mucosal IL-1α and β levels (pg/mg of biopsy) were estimated (ELISA) in 82/221 patients with and without SIBO (≥10(5)  CFU/mL upper gut aspirate bacteria).

KEY RESULTS

Genotype 1/1 (IL-1RA over-producer) was less frequent among patients than controls (p = 0.007); genotypes 1/3 (p = 0.012, OR = 3.301, 95% CI = 1.31-8.35) and 2/3 (both under-producers; p = 0.009, OR = 7.703, 95% CI = 1.66-35.82) were commoner among IBS. Fifteen of 82 (18.3%) patients had SIBO. Levels of IL-1α and β were higher among patients with SIBO than without (IL-1α: 35.4 [20.1-66.8] vs 25.5 [4.2-65.3], p < 0.001; IL-1β: 206.8 [133.5-365.9] vs 93.1 [25.5-197.7], p < 0.001) and those with bloating than without (p = 0.012; p = 0.015). IL-1β was higher among patients with Bristol stool type 6 than those with type 1-2 (p = 0.002) and type 3-5 (p = 0.007).

CONCLUSIONS & INFERENCES

Polymorphisms 1/1 (IL-1RA over-producer) was infrequent and 1/3 and 2/3 (under-producers) frequent among IBS. Increased IL-1α and β levels were associated with SIBO. Increased IL-1β level was predominantly associated with bloating and loose stools (Bristol type 6).

[Current issues in functional dyspepsia]

Functional dyspepsia is one of the most common gastrointestinal disorders encountered in clinical practice. Functional dyspepsia is currently defined by Rome III criteria as the chronic dyspeptic symptoms (postprandial fullness, early satiety, epigastric pain or burning) in the absence of underling structural or metabolic disease that readily explain the symptoms. According to the Rome III consensus, functional dyspepsia can be subdivided into postprandial distress syndrome (PDS) and epigastric pain syndrome (EPS). Although the Rome III criteria have been published more than 8 years ago, not much effort has been put into validating these criteria and direct scientific evidence supporting the validity of the subdividing functional dyspepsia into PDS and EPS are lacking. This article is intended to review the validity of the Rome III criteria on the subdivisions of functional dyspepsia, i.e. PDS and EPS. The impact of sleep disorder, Helicobacter pylori-associated dyspepsia, and the emerging drug therapies in functional dyspepsia will also be discussed in this article.

Irritable bowel syndrome: recent developments in diagnosis, pathophysiology, and treatment

The diagnosis of irritable bowel syndrome (IBS) remains a diagnosis of exclusion, whereby an extensive investigation is performed to exclude other organic diseases that may explain the symptoms of patients. Attempts to have a positive diagnosis based on symptom assessments failed to achieve widely use in clinical practice. Abnormalities in the gastrointestinal endocrine cells in IBS patients have been reported recently, providing evidence that IBS is an organic disorder, and opening the door to the use of these abnormalities as markers for a positive diagnosis of IBS. New and promising drugs for the treatment of IBS with constipation as the predominant symptom are currently on the market, and the treatment results have been satisfactory thus far.

Rome III criteria cannot distinguish patients with chronic gastritis from those functional dyspepsia patients

BACKGROUND

Functional dyspepsia is thought to be a diagnosis made after excluding endoscopically detectable lesions by the current Rome III criteria. However, whether these "functional dyspepsia" patients were diagnosed appropriately is still controversial.

MATERIALS AND METHODS

A total of 223 patients diagnosed with functional dyspepsia by Rome III criteria were enrolled. All patients were submitted to endoscopic examination, rapid urease test, and histologic evaluation. We also appraised the effect of a 7-day treatment based on the Glasgow Dyspepsia Severity Score.

RESULTS

Helicobacter pylori infection and neutrophil infiltration were found in 37.7% and 36.3% cases, respectively, and were both more frequent in the subgroup with epigastric pain symptom (EPS) than in the other two subgroups. In addition, neutrophil infiltration was more common and severe in the H. pylori-positive individuals than in the patients without infection (Mann-Whitney U-test = 431.500, p < .001). The treatment was useful in symptom improvement of all three subgroups, and the EPS subgroup had the greatest change of symptom scores before and after treatment as compared with the subgroup with postprandial distress symptom (PDS) and PDS/EPS subgroup (χ(2) = 42.745, p < .001), and the eradication of H. pylori revealed a statistical significant difference in different subgroups (χ(2) = 11.300, p = .001).

CONCLUSIONS

Our findings showed that many H. pylori-positive subjects diagnosed as "functional dyspepsia" were actually chronic gastritis patients, especially the EPS cases who are more likely to be patients with "active gastritis under microscope," and also benefit most from the treatment of proton-pump inhibitors or eradication of H. pylori.

Is irritable bowel syndrome an organic disorder?

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that is generally considered to be functional because there appears to be no associated anatomical defect. Stress and psychological factors are thought to play an important role in IBS. The gut neuroendocrine system (NES), which regulates all functions of the gastrointestinal tract, consists of endocrine cells that are scattered among the epithelial cells of the mucosa, and the enteric nervous system. Although it is capable of operating independently from the central nervous system (CNS), the gut NES is connected to and modulated by the CNS. This review presents evidence for the presence of an anatomical defect in IBS patients, namely in the gastrointestinal endocrine cells. These cells have specialized microvilli that project into the lumen and function as sensors for the luminal content and respond to luminal stimuli by releasing hormones into the lamina propria, which starts a chain reaction that progresses throughout the entire NES. The changes in the gastrointestinal endocrine cells observed in IBS patients are highly consistent with the other abnormalities reported in IBS patients, such as visceral hypersensitivity, dysmotility, and abnormal secretion.

[Functional gastrointestinal diseases]

Functional dyspepsia (FD) and irritable bowel syndrome (IBS) are the most important functional gastrointestinal diseases (FGID), and both affect about 5-15 % of the German population. The patients' symptoms are caused by disturbances of gastrointestinal (GI) motility, secretion and sensitivity. Central processing of visceral afferences is disturbed, and the course of the disease and individual symptom perception are influenced by psychosocial factors. Diagnosis of FD and IBS is based on a compatible symptom pattern, absence of alarm symptoms and exclusion of relevant differential diagnoses. The diagnosis of FD requires a normal upper GI endoscopy. Current German guidelines also demand a normal colonoscopy for diagnosis of IBS. Basic therapeutic measures include explanation of the nature of the disease and its harmlessness quo ad vitam . Individual trigger factors should be identified and eliminated if possible. Drug therapy of persisting complaints is guided by the dominant symptom.

The inhibitory effect of tongxieyaofang on rats with post infectious irritable bowel syndrome through regulating colonic par-2 receptor

Background

The aims of this study were to evaluate the effect and mechanism of a traditional Chinese medicine formula: Tongxieyaofang (TXYF) on Rats with Post Infectious Irritable Bowel Syndrome (PI-IBS).

Methods

SD male rats in adult were used to model PI-IBS and treated with TXYF at three dosage for 14 consecutive days, and then visceral sensation and the frequency of stool in PI-IBS rats were investigated. In addition, the contents of SP, TNF- α and IL-6 in colonic mucosal were analyzed by ELISA. Moreover faecal serine protease activity and PAR-2 mRNA expression were measured by ultraviolet spectrophotometry and RT-PCR, respectively.

Results

Our study showed that TXYF attenuated visceral hyperalgesia and inhibited stool frequency in Campylobacter-stimulated Post Infectious Irritable Bowel Syndrome (PI-IBS) rats. Furthermore, TXYF decreased the colonic SP, TNF- α and IL-6 content in PI-IBS rats. In addition, the up-regulated colonic mucosa PAR-2 mRNA expression in PI-IBS rats was significantly suppressed by orally TXYF.

Conclusions

TXYF attenuated PI-IBS symptom by attenuating behavioral hyperalgesia and anti-diarrhea, the underlying mechanism was mediated by inhibiting PAR-2 receptor expression, reducing the levels of SP, TNF- α and IL-6 in colonic mucosa and decreasing faecal serine protease activity.

High-potency sucralfate prevents and rapidly reverses chemo-radiation mucositis in a patient with stage 4b head and neck cancer

AIM: To study usefulness of high-potency sucralfate (HPS) in a patient with chemoradiation mucositis and discuss its mechanism of action.

METHODS: HPS, a non-covalently cross-link of sucralfate, cations and bidentate anionic chelators, has a maintains a surface concentration of sucralfate 3 h following administration that is 7-23 fold that possible with standard-potency sucralfate. The accelerated mucosal healing and pain alleviation of HPS in patients with erosive esophageal reflux, prompted its use in this patient with chemoradiation mucositis of the oropharynx and alimentary tract. A literature-based review of the immuno-modulatory effects of sucralfate is discussed.

RESULTS: Within 48 h of intervention: (1) there was complete disappearance of oral mucositis lesions; tenderness with (2) patient-reported disappearance of pain, nausea and diarrhea; patient required (3) no opiate analgesia and (4) no tube-feeding supplements to regular diet. Dysgeusia and xerostomia persisted. A modified Naranjo Questionnaire score of 10 supported the likelihood that HPS intervention caused the observed clinical effects. No adverse reactions noted.

CONCLUSION: In this patient HPS was useful to treat chemo-radiation mucositis of the oropharynx and alimentary tract. HPS may directly or indirectly facilitate an immunomodulatory mechanism involving accelerated growth factor activation, which may be a new target for therapeutic intervention in such patients.

Low prevalence of 'classical' microscopic colitis but evidence of microscopic inflammation in Asian irritable bowel syndrome patients with diarrhoea

Background

There is increasing evidence for the role of microscopic inflammation in patients with IBS. We aimed to examine the prevalence of microscopic colitis and inflammation in Malaysian IBS patients with diarrhoea (IBS-D).

Methods

Consecutive patients who met the Rome III criteria for IBS-D and asymptomatic controls were prospectively recruited. Colonoscopy was performed in all study subjects and systematic biopsies taken from all segments of the colon. The diagnosis of lymphocytic colitis and collagenous colitis was made using previously defined criteria. Patients with post infectious IBS were excluded.

Results

120 subjects (74 IBS-D, 46 controls) were recruited during the study period. In the IBS-D group, the colonoscopic (macroscopic) findings were as follows; normal findings n = 58 (78.4%), diverticula disease n = 5 (6.8%), diminutive polyps n = 9 (12.2%) and haemorrhoids n = 2(2.7%). No subject under the age of 40 had any significant findings. Microscopically, there was only one case (1.3%) with histology consistent with collagenous colitis. However, the IBS-D patients had a higher prevalence of moderate microscopic inflammation (n = 11, 14.9%) compared to controls (n = 1, 2.2%) (p = 0.005).

Conclusions

‘Classical’ microscopic colitis is uncommon in Malaysian patients with IBS-D but a significant number of adults showed evidence of microscopic inflammation.

Postinfectious functional gastrointestinal disorders: a focus on epidemiology and research agendas

Epidemiologic research is fundamental and complementary to our understanding of disease and development of primary, secondary, and tertiary interventions. To put the current evidence into context and identify gaps and research priorities in the areas of disease attribution, burden of disease, clinical characterization, and management of postinfectious functional gastrointestinal disorders (PI-FGDs), we took a multidisciplinary approach from the domains of infectious disease, gastroenterology, epidemiology, and public health. Our review of data from these disciplines found that, despite a complete understanding of pathoetiology, studies continue to accumulate and point toward evidence of a causal association for FGD. For some FGDs, Bradford Hill's criteria for causality yield more certainty than other criteria. In addition, the growing recognition of the impact of acute foodborne illness on economics and society is leading to exploration of the potential long-term health effects and disease burden of PI-FGDs, although a paucity of data exist in terms of pathogen-specific risk, disability duration, and relevant disability weights. Lastly, the understanding of PI-FGDs is changing the way research is approached and suggests a need for a more expansive exploration of biologic mechanisms and how FGDs are categorized. Areas of research priorities are catalogued in this paper and will hopefully provide inspiration for future studies and contributions to the field of gastroenterology.

Cytokine gene polymorphisms are associated with irritable bowel syndrome: a systematic review and meta-analysis

BACKGROUND

Low-grade inflammation has been increasingly implicated in the pathophysiology of irritable bowel syndrome (IBS). Imbalances of pro- and anti-inflammatory cytokines and polymorphisms in cytokine genes have been reported in IBS; however, these findings have not been consistently observed. This may be due to small sample sizes and differences in ethnicities. Therefore, we performed a meta-analysis on the studies that investigated cytokine gene polymorphisms in IBS patients compared to healthy controls.

METHODS

A PubMed and EMBASE search was performed, and cytokine gene polymorphisms, which had been investigated in at least two case-control studies, were evaluated. Pooled odds ratios (OR) for the genotypes were calculated using random- or fixed-effects models.

KEY RESULTS

Five studies that investigated interleukin-10 (IL-10; -1082 G/A), transforming growth factor-β1 (TGF-β1; +869 T/C and +915 G/C) and tumor necrosis factor (TNF; -308 G/A) polymorphisms in IBS patients and controls were included. High producer IL-10 (-1082 G/G; OR: 0.64 [95% CI: 0.48-0.87]) was significantly associated with a decreased risk of IBS. The intermediate producer TGF-β1 (+915 G/C) genotype showed a tendency toward decreasing the risk of IBS. No associations were found between TNF (-308 G/A) genotypes and IBS in the whole meta-analysis although an analysis of Asian studies revealed an association between TNF (-308 G/A and G/G) genotypes and IBS (OR: 0.50 [95% CI: 0.29-0.85]), and 1.82 [95% CI: 1.08-3.07], respectively).

CONCLUSIONS & INFERENCES

This meta-analysis indicates a role for IL-10 polymorphisms in IBS in general and TNF in Asian populations. Whether or not gene polymorphisms are associated with alterations in cytokine levels leading to functional effects at the level of the gut needs further investigation.

Trimebutine as a potential antimicrobial agent: a preliminary in vitro approach

AIM

The aim of this preliminary study was to investigate the in vitro effect of "non-antibiotic" trimebutine against reference strains Staphylococcus aureus ATCC 29213, ATCC 25923, Escherichia coli ATCC 25922, ATCC 35218, Pseudomonas aeruginosa ATCC 27853 and Enterococcus faecalis ATCC 29212; microbiota that are potentially involved in the pathophysiology of post-infectious functional gastrointestinal disorders.

METHODS

Trimebutine activity was assessed by the broth microdilution method according to Clinical and Laboratory Standards Institute recommendations against reference strains S. aureus ATCC 29213 and ATCC 25923, E. coli ATCC 25922 and ATCC 35218, P. aeruginosa ATCC 27853 and E. faecalis ATCC 29212. Bactericidal activity of the compound was determined by spreading a 10 μL aliquot on Mueller-Hinton agar from each dilution showing non-visible growth. All tests were carried out in triplicate.

RESULTS

Trimebutine was active against all strains tested presenting with MIC ranging from 1024 to 4000 mg/L. MIC and MBC were similar for E. coli ATCC 25922 and P. aeruginosa ATCC 27853 whereas for Gram-positive isolates and E. coli ATCC 35218 the MBC was higher.

CONCLUSIONS

We demonstrated the in vitro bacteriostatic/bactericidal activity of trimebutine against bacteria frequently colonizing the gastrointestinal tract and potentially involved in human gastrointestinal infections that might trigger post-infectious functional gastrointestinal disorders.

Imbalanced shift of cytokine expression between T helper 1 and T helper 2 (Th1/Th2) in intestinal mucosa of patients with post-infectious irritable bowel syndrome

Background

Irritable bowel syndrome (IBS) is a common functional bowel disorder. The post-infectious IBS (PI-IBS) occurs in IBS patients with a history of intestinal infection preceding the onset of symptoms. However, the underlying cause of PI-IBS is not fully understood, and the purpose of this study was to investigate the immune regulatory mechanism of PI-IBS.

Methods

Participants enrolled in this study were divided into three groups including PI-IBS patients (n = 20), IBS patients without a history of infection (non-PI-IBS, n = 18), and healthy controls (n = 20). The expression levels of the Th1-derived cytokines IFN-γ and IL-12, and the Th2-derived cytokines IL-4 and IL-10 in the mucosal specimens, and in the ascending colon, the descending colon, and the rectal segments were measured by RT-PCR and western blot.

Results

The IFN-γ mRNA levels in the intestinal mucosa were significantly higher in the PI-IBS group than in the non-PI-IBS or control group (both P < 0.05), but there was no difference between the non-PI-IBS and control groups. A trend toward IFN-γ protein upregulation was found in the PI-IBS group, while the IL-12 and IL-4 mRNA and protein levels were not different between any groups. The IL-10 mRNA and protein levels in the PI-IBS group were both significantly lower than in the non-PI-IBS or control groups (P < 0.05, respectively), but there was no difference between the non-PI-IBS and control groups. There were no differences in the cytokine mRNA and protein levels among the ascending colon, the descending colon, and the rectum of all groups.

Conclusions

An increase in IFN-γ levels and a decrease in IL-10 levels were found in the intestinal mucosa of PI-IBS patients, suggesting that the infection may affect the Th1/Th2 balance. Thus, the dysregulation of the immune response is likely an important cause of IBS.

Chronic gastrointestinal consequences of acute infectious diarrhea: evolving concepts in epidemiology and pathogenesis

Acute infectious diarrhea is a frequent occurrence both in the developing world, where it results in considerable mortality, and in developed countries, where it accounts for a significant number of health visits, hospitalizations, and medical and non-medical losses. Recent evidence in basic, clinical, and epidemiological science domains has emerged that suggest that the burden caused by these infections is not limited to the acute illness, but may result in triggering or contributing to the pathogenesis of a number of chronic health problems. This review considers the breadth of this information for the purpose of consolidating what is currently known, identifying gaps in knowledge, and describing future directions and policy implications related to the chronic consequences of acute infectious diarrhea. A unifying hypothesis of this review is that infections may trigger a number of long-lasting changes in gut physiology and immunity that can increase the risk to a variety of chronic gastrointestinal diseases, particularly in genetically susceptible individuals.

A global perspective on irritable bowel syndrome: a consensus statement of the World Gastroenterology Organisation Summit Task Force on irritable bowel syndrome

Irritable bowel syndrome (IBS) is common in western Europe and North America, and many aspects of its epidemiology, risk factors, and natural history have been described in these regions. Recent data suggest, however, that IBS is also common in the rest of the world and there has been some evidence to suggest some differences in demographics and presenting features between IBS in the west and as it is experienced elsewhere. The World Gastroenterology Organization, therefore, established a Task Force comprising experts on the topic from all parts of the world to examine IBS from a global perspective. IBS does, indeed, seem to be common worldwide though with some significant variations in prevalence rates between regions and countries and there may well be some potentially interesting variations in presenting symptoms and sex distribution. The global map of IBS is far from complete; community-based prevalence data is not available from many areas. Furthermore, while some general trends are evident in terms of IBS impact and demographics, international comparisons are hampered by differences in diagnostic criteria, study location and methodology; several important unanswered questions have been identified that should form the basis for future collaborative research and have the potential to shed light on this challenging disorder.

Lower serum IL-10 is an independent predictor of IBS among volunteers in Mexico

OBJECTIVES

Studies suggest that altered immune activation, manifested by an imbalance in anti- and pro-inflammatory cytokine levels, exists in a subgroup of irritable bowel syndrome (IBS) patients. However, similar studies have not been conducted in Latin populations. The objective of this study was to measure serum levels of interleukin (IL)-10 and tumor necrosis factor (TNF)-α in subjects fulfilling symptom criteria for IBS and controls.

METHODS

Volunteers (n=178) from a university population in Mexico City, participated in the study. Of the sample, 34.8% met Rome II criteria for IBS and 65.2% were designated as controls. Serum cytokines were measured by enzyme-linked immunoabsorbent assay. Analysis of covariance models were used to test main effects between gender, IBS symptoms, and bowel habit subtype to explain the cytokine serum levels. Statistical models were tested using body mass index as a covariate.

RESULTS

IL-10 levels were significantly lower in IBS vs. controls (mean (95% confidence interval): 15.6 (14.8, 16.3) vs. 18.6 (17.9, 19.4) pg/ml, P<0.001), while TNF-α levels were higher in IBS (20.9 (19.1, 23.0) vs. 17.9 (16.7, 19.3) pg/ml, P=0.010). IBS and female gender were independent predictors for IL-10 (P<0.05). In contrast, female gender was an independent predictor for TNF-α. In addition, women with IBS-D had the lowest IL-10 (P<0.001) and highest TNF-α (P=0.021) vs. other subtypes.

CONCLUSIONS

The lower serum IL-10 in our subjects fulfilling IBS Rome II symptom criteria suggests an altered immune regulation. Further studies are needed to elucidate if a lower serum IL-10 may be useful as a biomarker for IBS in the Mexican population, especially for women with IBS-D.

Erythrocyte sedimentation rate - possible role in determining the existence of the low grade inflammation in Irritable Bowel Syndrome patients

Irritable Bowel Syndrome (IBS), the most prevalent functional gastrointestinal disorder, is best described by the presence of recurrent symptoms of abdominal pain, diarrhea and/or constipation. It has been thought that IBS is stress-related disorder with no known structural abnormalities, e.g. infectious, biochemical or metabolic causes. But, recent evidence suggests that inflammation within the gastrointestinal tract may be of great importance in the pathogenesis of IBS. Our question is could the conventional and widely available general biological markers of inflammation such as erythrocyte sedimentation rate (ESR) be indicator of microscopic inflammatory process in some IBS patients? We hypothesize that mild inflammation in IBS patients could be detected by meaning of a sensitive but cheap and ubiquitous test - ESR. Furthermore we assume that ESR would be related with the disease severity index and decreased general and disease-specific health-related quality of life (HRQoL). A pilot study has been conducted with 86 outpatients (65% female) with IBS, average age 47.76 (SD=13.68). The preliminary results were partly in favor of our hypothesis. They showed that IBS patients with higher ESR expressed lower disease-specific HRQoL (e.g. they expressed more bowel symptoms, social and emotional disturbances related to disease). No significant correlations were found between ESR and the disease severity as well as general HRQoL.

The role of human defensins in gastrointestinal diseases

In clarifying the pathogenesis of inflammatory bowel diseases, a dysregulation of the adaptive immune function was the main focus of research in the last decade. With increasing knowledge of antimicrobial peptides, a primary disturbed barrier function and the system of innate immunity has recently received increasing attention. Contrary to the common understanding of irritable bowel syndrome as a functional disorder, there is first evidence for an involvement of innate immunity for this condition. Peptides with high relevance seem to be the class of human defensins. This article will thus discuss current advances in immunologic research of inflammatory bowel disease and irritable bowel syndrome, focusing on defensins and their possible role as biomarkers of these diseases.

Abnormal immune regulation and low-grade inflammation in IBS: does one size fit all?

Evidences suggest that there is low-grade inflammation in the colonic mucosa and/or a state of immune activation in patients with irritable bowel syndrome (IBS). Results from available studies are inconsistent mainly because of differences in measures, methodologies and study populations. In this issue, Chang et al. evaluated a comprehensive set of cytokines, immune markers and immune-related cells in patients with non post infectious IBS (non PI-IBS) and controls. The main finding was a lower expression of the mRNA of the anti-inflammatory IL-10 cytokine in the colonic mucosa of women with non PI-IBS without any differences in the cell counts. These results suggest that in non PI-IBS, there is altered immune regulation/activation without evidence of low-grade mucosal inflammation. Further, PI and non PI-IBS may be associated with different alterations in immune function/activation.

Acute experimental endotoxemia induces visceral hypersensitivity and altered pain evaluation in healthy humans

Growing evidence suggests that systemic immune activation plays a role in the pathophysiology of pain in functional bowel disorders. By implementing a randomized crossover study with an injection of endotoxin or saline, we aimed to test the hypothesis that endotoxin-induced systemic inflammation increases visceral pain sensitivity in humans. Eleven healthy men (mean ± standard error of the mean age 26.6 ± 1.1 years) received an intravenous injection of either lipopolysaccharide (LPS; 0.4 ng/kg) or saline on 2 otherwise identical study days. Blood samples were collected 15 min before and 1, 2, 3, 4, and 6h after injection to characterize changes in immune parameters including proinflammatory cytokines. Rectal sensory and pain thresholds and subjective pain ratings were assessed with barostat rectal distensions 2h after injection. LPS administration induced an acute inflammatory response indicated by transient increases in tumor necrosis factor alpha, interleukin 6, and body temperature (all P<.001). The LPS-induced immune activation increased sensitivity to rectal distensions as reflected by significantly decreased visceral sensory and pain thresholds (both P<.05) compared to saline control. Visceral stimuli were rated as more unpleasant (P<.05) and inducing increased urge to defecate (P<.01). Pain thresholds correlated with interleukin 6 at +1h (r=0.60, P<.05) and +3h (r=0.67, P<.05) within the LPS condition. This report is novel in that it demonstrates that a transient systemic immune activation results in decreased visceral sensory and pain thresholds and altered subjective pain ratings. Our results support the relevance of inflammatory processes in the pathophysiology of visceral hyperalgesia and underscore the need for studies to further elucidate immune-to-brain communication pathways in gastrointestinal disorders.

Restless legs syndrome--theoretical roles of inflammatory and immune mechanisms

Theories for restless legs syndrome (RLS) pathogenesis include iron deficiency, dopamine dysregulation and peripheral neuropathy. Increased prevalence of small intestinal bacterial overgrowth (SIBO) in controlled studies in RLS and case reports of post-infectious RLS suggest potential roles for inflammation and immunological alterations. A literature search for all conditions associated with RLS was performed. These included secondary RLS disorders and factors that may exacerbate RLS. All of these conditions were reviewed with respect to potential pathogenesis including reports of iron deficiency, neuropathy, SIBO, inflammation and immune changes. A condition was defined as highly-associated if there was a prevalence study that utilized an appropriate control group. Small case reports were recorded but not included as definite RLS-associated conditions. Fifty four diseases, syndromes and conditions have been reported to cause and/or exacerbate RLS. Of these, 38 have been reported to have a higher prevalence than age-matched controls, 9 have adequate sized reports and have general acceptance as RLS-associated conditions and 7 have been reported in case report form. Overall, 42 of the 47 RLS-associated conditions (89%) have also been associated with inflammatory and/or immune changes. In addition, 43% have been associated with peripheral iron deficiency, 40% with peripheral neuropathy and 32% with SIBO. Most of the remaining conditions have yet to be studied for these factors. The fact that 95% of the 38 highly-associated RLS conditions are also associated with inflammatory/immune changes suggests the possibility that RLS may be mediated or affected through these mechanisms. Inflammation can be responsible for iron deficiency and hypothetically could cause central nervous system iron deficiency-induced RLS. Alternatively, an immune reaction to gastrointestinal bacteria or other antigens may hypothetically cause RLS by a direct immunological attack on the central or peripheral nervous system.

Gastrointestinal infections and the development of irritable bowel syndrome

PURPOSE OF REVIEW

Approximately 10% of the millions of persons with functional gastrointestinal disorders (FGDs) including irritable bowel syndrome (IBS) had their illness onset following an acute bout of infectious diarrhea and are referred to as having postinfectious (PI) FGD or PI-IBS. Recent studies have helped to identify the pathogenesis and natural history of these disorders.

RECENT FINDINGS

Groups of patients with acute diarrhea or dysentery (passage of grossly bloody stools) are being followed for development of PI-IBS. Persistent mucosal inflammation, air trapping in the gut, and alteration of intestinal motility contribute to the disease symptoms in genetically susceptible persons. The prognosis of postinfectious forms of IBS is more favorable compared with people with idiopathic forms of the disorder.

SUMMARY

With full characterization of postdiarrhea forms of FGDs, we should be able to define the mechanisms of disease early in the course of chronic illness and to better understand the more common idiopathic forms of the disease. We are likely to identify specific alteration of gut pathophysiology in postinfectious FGDs and to then classify them not as a poorly characterized group of functional disorders but as specific gastrointestinal disorders.

The role of eosinophils and mast cells in intestinal functional disease

Functional gastrointestinal disorders (FGIDs) are common and currently defined by a symptom-based classification with no discernable pathology. In functional dyspepsia (FD), the duodenum is now implicated as a key area where symptoms originate.This is attributed to immune activation with increasing evidence indicating a role for duodenal eosinophilia. In irritable bowel syndrome (IBS), mastocytosis has been documented throughout the small and large intestine. Eosinophils and mast cells are an important link between innate and adaptive immunity, and are important in allergic type TH2 inflammation. Eosinophils may give rise to symptoms due to release of preformed cytokine proteins, which trigger neural excitation, muscle spasm, and pain. The close relationship of mast cells to nerves in IBS may similarly give rise to symptoms. Genetic studies also support of the role of innate immunity in FGIDs. The data supporting a prime role for eosinophils and mast cells in subsets of FD and IBS has become credible, and these data should be used to implement advances in diagnosis and therapeutic trials.

Irritable bowel syndrome, gut microbiota and probiotics

Irritable bowel syndrome (IBS) is a complex disorder characterized by abdominal symptoms including chronic abdominal pain or discomfort and altered bowel habits. The etiology of IBS is multifactorial, as abnormal gut motility, visceral hypersensitivity, disturbed neural function of the brain-gut axis and an abnormal autonomic nervous system are all implicated in disease progression. Based on recent experimental and clinical studies, it has been suggested that additional etiological factors including low-grade inflammation, altered gut microbiota and alteration in the gut immune system play important roles in the pathogenesis of IBS. Therefore, therapeutic restoration of altered intestinal microbiota may be an ideal treatment for IBS. Probiotics are live organisms that are believed to cause no harm and result in health benefits for the host. Clinical efficacy of probiotics has been shown in the treatment or prevention of some gastrointestinal inflammation-associated disorders including traveler's diarrhea, antibiotics-associated diarrhea, pouchitis of the restorative ileal pouch and necrotizing enterocolitis. The molecular mechanisms, as cause of IBS pathogenesis, affected by altered gut microbiota and gut inflammation-immunity are reviewed. The effect of probiotics on the gut inflammation-immune systems and the results from clinical trials of probiotics for the treatment of IBS are also summarized.

Prevalence and risk factors for irritable bowel syndrome among middle school teachers in areas affected by Wenchuan earthquake

AIM: To analyze the prevalence, clinical characteristics, and risk factors for irritable bowel syndrome (IBS) among middle school teachers in areas affected by Wenchuan earthquake.

METHODS: Multi-stage random sampling was adopted to select 269 teachers from three middle schools in earthquake-affected areas and three in non-affected areas to conduct epidemiological investigation of IBS.

RESULTS: The overall prevalence of IBS, which was diagnosed according to the revised Rome II criteria, was 22.5% (95%CI: 17.3%-24.7%). The prevalence of IBS among teachers in earthquake-affected areas was significantly higher than that in non-affected areas (27.9% vs 15.7%, P < 0.05). No significant difference was found in the prevalence of anxiety and depression between teachers in earthquake-affected areas and those in non-affected areas. However, the prevalence of anxiety and depression was significantly higher in teachers with IBS than in those without IBS (P < 0.05).

CONCLUSION: The prevalence of IBS among teachers was higher in earthquake-affected areas than in non-affected areas. The prevalence of anxiety and depression was higher in teachers with IBS than in those without IBS. Earthquake experience might increase the prevalence of IBS among middle school teachers.

What is the difference between Helicobacter pylori-associated dyspepsia and functional dyspepsia?

Advances in basic and clinical research have revealed that Helicobacter pylori (H. pylori) infection plays an important role in the development of gastroduodenal dysmotility and hypersensitivity, as also in dyspepsia symptoms. In addition, recent studies have proposed an inflammation-immunological model for the pathogenesis of functional dyspepsia. Since H. pylori is the major microbe that provokes a gastroduodenal inflammatory response, it should not be overlooked when considering the pathophysiology of dyspepsia symptoms. In fact, population-based studies have demonstrated that H. pylori is detected more frequently in dyspepsia patients. However, although many clinical studies tried to reveal the association of H. pylori infection with gastric motility dysfunction or hypersensitivity, the results have been conflicting. On the other hand, many etiological features were revealed for the development of H. pylori-associated dyspepsia, such as abnormal ghrelin or leptic secretion, altered expression of muscle-specific microRNAs, and duodenal inflammatory cell infiltration. In addition, therapeutic strategy for H. pylori-associated dyspepsia would be different from H. pylori-negative functional dyspepsia. This review focuses the issue of whether H. pylori-associated dyspepsia should be considered as a different disease entity from functional dyspepsia.

Duodenal administered seal oil for patients with subjective food hypersensitivity: an explorative open pilot study

Short-term duodenal administration of n-3 polyunsaturated fatty acid (PUFA)-rich seal oil may improve gastrointestinal complaints in patients with subjective food hypersensitivity, as well as joint pain in patients with inflammatory bowel disease (IBD). The aim of the present explorative pilot study was to investigate whether 10-day open treatment with seal oil, 10 mL self-administrated via a nasoduodenal tube 3 times daily, could also benefit nongastrointestinal complaints and quality of life (QoL) in patients with subjective food hypersensitivity. Twenty-six patients with subjective food hypersensitivity, of whom 25 had irritable bowel syndrome (IBS), were included in the present study. Before and after treatment and 1 month posttreatment, patients filled in the Ulcer Esophagitis Subjective Symptoms Scale (UESS) and the Gastrointestinal Symptom Rating Scale (GSRS) for gastrointestinal symptoms and subjective health complaints (SHC) inventory for nongastrointestinal symptoms in addition to short form of the Nepean dyspepsia index (SF-NDI) for evaluation of QoL. Compared with baseline, gastrointestinal, as well as nongastrointestinal, complaints and QoL improved significantly, both at end of treatment and 1 month posttreatment. The consistent improvements following seal oil administration warrant further placebo-controlled trials for confirmation of effect.

From cytokines to toll-like receptors and beyond - current knowledge and future research needs in irritable bowel syndrome

The irritable bowel syndrome (IBS) is a complex disorder in which psychosocial, cultural and biological factors, interact. Recent knowledge in the pathophysiology of IBS, seem to combine issues such as a low grade inflammation or immune activation and dysbiosis that can trigger or exacerbate IBS. On the other hand, stress mediated through the hypothalamic-pituitary-adrenal axis can produce motility abnormalities that can modify the microbiota as well, with the subsequent immune activation in the mucosa and stimulation of nerve terminals, generating symptoms of IBS. Also, we speculate that, stress, dysbiosis or an underlying genetic predisposition, may increase the epithelial permeability leading to a contact between pathogens-associated molecular patterns and toll-like receptors in the deeper layers of the gut, developing a host immunity response and IBS generation. We believe that the role of toll-like receptors in IBS and elucidating the communication processes between the immune and the nervous system, warrant future research.

Do psychological factors predict symptom severity in patients with subjective food hypersensitivity?

OBJECTIVE

We examined whether psychological factors such as general and gastrointestinal symptom-specific anxiety and depression could predict symptom severity in patients with unexplained, self-reported (subjective) food hypersensitivity. For the purpose, we translated and validated the Visceral Sensitivity Index (VSI).

MATERIAL AND METHODS

Seventy consecutive patients completed questionnaires for Hospital Anxiety and Depression Scale, VSI, Irritable Bowel Syndrome Symptom Questionnaire, and Subjective Health Complaints Inventory. Relationship between scores on psychological factors and scores on somatic symptoms were studied by multiple regression analyses.

RESULTS

Most patients reported non-gastrointestinal symptoms in addition to their irritable bowel syndrome complaints, but general and symptom-specific anxiety, and depression could not explain a significant amount of the variance in somatic complaints. Gastrointestinal symptom-specific anxiety was a significant predictor of gastrointestinal complaints (p = 0.02), and age was the sole significant predictor of non-gastrointestinal complaints (p = 0.01). Approximately 90% of the total variance in symptom severity remained unexplained by the psychological factors. The Norwegian version of the VSI had satisfactory validity (Cronbach alfa = 0.93). Symptom-specific and general anxiety were significantly correlated (r = 0.48, p < or = 0.0001).

CONCLUSIONS

Psychological factors were not major predictors of symptom severity in patients with subjective food hypersensitivity. The Norwegian version of VSI had satisfactory validity.