Assessment of high-sensitivity CRP as a marker of micro-inflammation in irritable bowel syndrome

Evaluation of the Symptom-Based Diagnostic Criteria for Irritable Bowel Syndrome in Conjunction With Clinical Examinations and Laboratory Investigations

Background Irritable bowel syndrome (IBS) is a chronic condition characterized by persistent abdominal pain or discomfort and impaired bowel function. Symptoms often vary in onset and severity, are worse during flare-ups, and affect the patient's quality of life. A positive diagnosis of IBS based on clinical symptoms may lead to a better outcome. There are different diagnostic criteria like Kruis score, Manning criteria, Rome I, II, III, and IV criteria, and each new one addresses the deficiencies of the previous ones. We analyze the effectiveness of the most commonly used diagnostic criteria associated with clinical examinations and laboratory tests in treating IBS in these studies. Methodology This is a retrospective study in which data from IBS subjects were collected by simple random sampling and compared using Manning criteria, Kruis score, and Rome IV criteria. Laboratory tests included complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP). Results Of the 130 patients, IBS is more prevalent in adults aged 30-50 years, with a male predominance. The Kruis score outperformed the Manning criterion in distinguishing between organic bowel disease and IBS. This, together with the Rome IV criteria, increases the likelihood of identifying IBS. Conclusions Differentiating IBS from functional and organic gastrointestinal problems is critical. Irritable bowel syndrome can be diagnosed using symptom-based diagnostic criteria. Clinical observation and physical examination should be supplemented with laboratory indicators.

Functional gastrointestinal disorders. Overlap syndrome Clinical guidelines of the Russian Scientific Medical Society of Internal Medicine and Gastroenterological Scientific Society of Russia

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Burnout, but not job strain, is associated with irritable bowel syndrome in working adults

OBJECTIVE

Although stress is an important component of irritable bowel syndrome (IBS) pathophysiology, the possibility that work-related stress is implicated in the pathophysiology of IBS has not been widely studied. This study aimed to examine whether job strain (a combination of high job demands and low control at work) and/or burnout, the outcome of a gradual depletion of energetic resources resulting from chronic exposure to work-related stress, are associated with IBS.

METHODS

Fifty-five patients fulfilling the Rome III criteria for IBS and 214 matched healthy controls (HC) participated in this cross-sectional study. All participants completed a job strain measure, the Shirom - Melamed Burnout Measure (SMBM), and dietary and health questionnaires.

RESULTS

There was no significant difference in the prevalence of job strain between IBS patients and HC (25.5% vs. 23.0%, respectively). Job strain was not associated with increased IBS prevalence (adjusted OR = 1.99, 95% CI: 0.54-7.33). In contrast, the mean burnout score in the IBS group was significantly higher than in HC (2.9 ± 1.1 vs. 2.1 ± 0.8, p < .001). Burnout was associated with a 2.41-fold elevated prevalence of IBS (95% CI: 1.16-5.02), after adjusting for potential confounding variables including job strain. Moreover, the odds of having IBS increased in patients with a high burnout level (adjusted OR = 3.3, 95% CI:1.09-10.03).

CONCLUSION

Burnout, but not job strain, is associated with the prevalence of IBS in working adults.

Plasma AXIN1 expression exhibit negative correlations with inflammatory biomarkers and is associated with gastrointestinal symptoms in endometriosis

The cytoplasmic protein AXIN1 is involved in the Wnt signalling pathway and its expression is increased in patients with endometriosis compared with healthy controls. The aim of the present cross-sectional study was to further assess the levels of AXIN1 and other inflammatory biomarkers in patients with endometriosis. Patients with laparoscopy-verified endometriosis were recruited (n=172) and completed a questionnaire regarding socioeconomic factors, lifestyle habits and medical history. Plasma AXIN1 and high-sensitivity C-reactive protein (hs-CRP) levels were analysed by ELISA. The levels of calprotectin were determined in the faeces, and the haemoglobin concentration and number of erythrocytes, leukocytes and platelets were determined in the blood in a subgroup of 64 patients during clinical routine procedures. F-calprotectin expression was detected in 18 women (28.1%), who had more severe constipation and more frequently experienced incomplete evacuation when defecating, and 5 women (7.8%) exhibited elevated levels. P-AXIN1 levels were higher in patients who received hormonal treatment, and correlated inversely with faecal-calprotectin levels (P=0.003), B-haemoglobin levels (P=0.030) and the numbers of B-erythrocytes (P=0.033) and B-platelets (P=0.017), but were not correlated with hs-CRP levels (P=0.818). Higher levels of AXIN1 were associated with the duration of the gastrointestinal symptoms and with diarrhoea, constipation, vomiting and nausea and the intestinal symptoms' effect on quality of life, and tended to be associated with the duration of endometriosis. Hs-CRP expression was not associated with the clinical characteristics or symptoms of endometriosis, but higher levels were associated with obesity (P=0.002) and hormonal treatment (P=0.011). In conclusion, P-AXIN1 expression was negatively correlated with certain inflammatory biomarkers and was positively associated with gastrointestinal symptoms. P-AXIN1 levels were increased in patients who received hormonal treatment, highlighting the importance of obtaining native samples for future studies regarding its role in the development and presentation of endometriosis. However, hs-CRP and other studied biomarkers seemed to be of no value for the assessment and diagnosis of endometriosis.

A clinical model for identifying an inflammatory phenotype in mood disorders

Increasingly, clinical research has found inflammatory correlates of psychiatric disorders, particularly mood symptomatology. Biological measures may provide greater precision in many cases and may capture clinically-relevant inflammatory signposts, such as central obesity risk, inflammation-associated co-morbid medical conditions, or proinflammatory lifestyle choices. In order to expand understanding of the role of inflammation in mood disorders, we propose a more inclusive clinical model for capturing an inflammatory phenotype of depression by identifying clinically-relevant inflammatory phenotypes grounded in biology. Our model includes chronic conditions and lifestyle behaviors associated with clinically elevated inflammation in mood disorders. Elements of this "inflamed depression" model include: obesity, low HDL concentrations, elevated triglyceride concentrations, chronically elevated blood pressure, clinical diagnosis of hypothyroidism, migraines, rheumatoid arthritis, adult onset diabetes, inflammatory bowel diseases, inflammatory skin conditions, and lifestyle factors including smoking cigarettes and chronic stress.

Serum cholinesterase activity is elevated in female diarrhea-predominant irritable bowel syndrome patients compared to matched controls

BACKGROUND

Micro-inflammation is involved in the pathogenesis of irritable bowel syndrome (IBS). The parasympathetic nervous system, via acetylcholine (ACh), and its hydrolytic enzymes, plays a role in regulating inflammation. Increased serum cholinesterase activity, named cholinergic Status (CS), is associated with decreased inflammatory inhibition (ie, pro-inflammation). We assessed the association between IBS diarrhea-predominant (IBS-D) symptoms, CS, and inflammatory biomarkers.

METHODS

Women with IBS-D were prospectively recruited. Serum acetylcholinesterase (AChE), CS, and high-sensitivity C-reactive protein (hs-CRP) levels were analyzed and fecal calprotectin (FC) in a subgroup of patients. The control group included women attending routine health checkups (matched by age and BMI).

KEY RESULTS

Ninety-four women with IBS-D were compared to matched controls (1:1). Serum CS, AChE, and the AChE/butyrylcholinesterase (BChE) ratios were significantly increased in the IBS-D group compared to matched controls (P = 0.018, P = 0.001, and P = 0.004, respectively). Using a multiple logistic regression model, IBS-D was almost twice as likely in women with high CS compared to women with low CS (adjusted OR=1.84 (95% CI: 1.01-3.33), P = 0.045). Furthermore, IBS-D patients with higher hs-CRP levels demonstrated lower CS and BChE activity and elevated AChE and AChE/BChE ratios compared to patients with lower hs-CRP levels (P = 0.026, P = 0.036, P = 0.002; and P = 0.0007, respectively). CS was not correlated with the IBS symptoms score.

CONCLUSIONS AND INFERENCES

This is the first study to explore the potential role of serum CS in IBS-D. The findings emphasize the possible role of the autonomic nervous system and its anti-inflammatory properties in IBS.

Comparison and Assessment of Flixweed and Fig Effects on Irritable Bowel Syndrome with Predominant Constipation: A Single-Blind Randomized Clinical Trial

BACKGROUND

Irritable bowel syndrome with predominant constipation (IBS-C) is a common digestive disorder. The current therapy is inadequate and evidence regarding the effect of herbal therapies on the relief of affected individuals is insufficient. The aim of this study was to investigate the beneficial effects of flixweed and fig consumption on IBS-C symptoms.

METHODS

150 patients with IBS-C were enrolled in this randomized, controlled trial. All patients were randomly assigned to three groups and received an intervention for four months. The IBS severity score system and quality-of-life questionnaires were used for evaluating IBS-C symptoms. C-reactive protein levels, frequency of defecation and hard stool were also assessed.

RESULTS

Consumption of flixweed or fig, compared to a control group, caused a significant improvement in IBS symptoms including frequency of pain, distention, frequency of defecation and hard stool. Also, the findings showed a significant increase in quality of life, as well as satisfaction with overall bowel habits. However, flixweed and fig intake had no significant effects on abdominal pain severity and C-reactive protein levels.

CONCLUSIONS

In conclusion, consumption of flixweed or fig for four months would be a useful therapy for alleviating IBS-C symptoms and can be a beneficial option for first-line treatment.

Estrogen signaling deregulation related with local immune response modulation in irritable bowel syndrome

The etiology and pathogenesis underlying irritable bowel syndrome (IBS), a common gastrointestinal disorder are still unclear. Cumulating data suggest dysregulation of inflammatory and immune response pathways and changes of epithelial barrier function. The role of estrogens albeit varied, in responses of immune system is well documented. The aim of this study was to investigate estrogen receptors engagment in IBS subtypes, i.e. constipation predominant (IBS-C) and diarrhea predominant (IBS-D). Furthermore, we analyzed whether estrogen signaling is accompanied by alteration in expression of pro- and anti-inflammatory cytokines and microRNAs that can regulate among others genes involved in immune responses. It was found that estrogen receptor α (ERα) and G protein-coupled estrogen receptor (GPER) expression is up-regulated in IBS while estrogen receptor β (ERβ) appears to be down-regulated at mRNA but up-regulated at the protein level. When gender and female age were included statistically significant overexpression of ERα in IBS-D women under the age of 50, while of GPER in IBS-D men was stated. In all studied IBS samples disturbances in expression of cytokines IL-6, IL-10 and TNF-α as well as miR-145, miR-148-5p and miR-592 were observed. This research reveals the association of estrogen receptors with IBS. Simultaneous alterations of studied immunomodulatory cytokines and microRNAs suggest that in IBS dysregulation of local immune response may involve estrogen-dependent way.

Fecal and Mucosa-Associated Intestinal Microbiota in Patients with Diarrhea-Predominant Irritable Bowel Syndrome

BACKGROUND

Irritable bowel syndrome (IBS) has been associated with changes in the intestinal microbiota. Only a few studies have explored differences in the mucosa-associated microbiota between IBS patients and healthy controls (HC).

AIMS

To characterize and compare the microbiota in mucosal and fecal samples from carefully selected patients with IBS-D and HC.

METHODS

The cohort was composed of 23 diarrhea-predominant IBS (IBS-D) patients and 24 HC. Fresh stool samples were collected from participants prior to the collection of colonic mucosal samples from an unprepped bowel. After DNA extraction, 16S rRNA genes were sequenced by 454 pyrosequencing and analyzed using the QIIME pipeline.

RESULTS

The fecal microbiota (luminal niche) of IBS-D patients was found to have reduced enteric richness compared to HC (P < 0.05), whereas no differences were observed between the two groups within the mucosal microbiota. Within the luminal niche, the relative proportions of Faecalibacterium genus were found to be lower in IBS-D than in HC and the Dorea genus was higher in IBS-D. None of the taxa proportions were significantly different in IBS-D patients versus HC using an FDR of ≤ 0.1 when analyzing samples that appeared in > 25% samples of either niche.

CONCLUSION

Fecal and mucosal microbiota of IBS-D patients and HC are very similar and are not sufficient to explain the reported altered physiology and symptomatology of IBS-D. Future studies should investigate intestinal microbiome-dependent functional activity in addition to the fecal and mucosal-associated microbial composition.

Evaluation of chronic diarrhea and irritable bowel syndrome with diarrhea in adults in the era of precision medicine

Chronic diarrhea is a common clinical problem, affecting roughly 5% of the population in any given year. Evaluation and management of these patients can be difficult due to the extensive differential diagnosis of this symptom. Many patients with chronic diarrhea have structural problems, such as inflammatory bowel disease or celiac disease, that can be readily identified. Others do not, and often are given a diagnosis of irritable bowel syndrome with diarrhea (IBS-D). When based on generally accepted clinical criteria, a diagnosis of IBS-D identifies a group of patients who are unlikely to have disorders producing anatomical changes in the gut. It is less clear that a diagnosis of IBS-D identifies a specific pathophysiology or leads to better management of symptoms. Disorders such as small intestinal bacterial overgrowth, bile acid malabsorption, food intolerance, and motility disorders may account for symptoms in patients with IBS-D. More effective tests are being developed to identify the clinical problems underlying IBS-D and may lead to more specific diagnoses that may improve the results of therapy. Application of the principles of precision medicine (identifying a specific mechanism for disease and applying treatments that work on that mechanism) should lead to more expeditious diagnosis and treatment for patients with chronic diarrhea including IBS-D, but currently is limited by the availability of sufficiently sensitive and specific tests for underlying mechanisms that can predict response to treatment.

Interleukin-6 in irritable bowel syndrome: A systematic review and meta-analysis of IL-6 (-G174C) and circulating IL-6 levels

BACKGROUND

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder which presents with abdominal pain and alterations of the bowel habits. The pathophysiology of IBS is not well-recognized. Low grade inflammation has been suggested as one of the underlying mechanisms of IBS. Variations in the circulating pro-inflammatory interleukin-6 (IL-6) levels and IL-6 gene polymorphisms have been demonstrated in IBS. However, the results of published studies are not consistent, probably due to their small sample sizes. To address this inconsistency, we conducted the current systematic review and meta-analysis on serum/plasma IL-6 levels and IL-6 (-G174C; rs1800795) gene polymorphism in IBS.

METHODS

PubMed was searched in July 2016. Case-control studies on serum/plasma IL-6 levels and IL-6 (-G174C) gene polymorphisms in IBS versus control were retrieved. The quality of studies was evaluated based on the modified Newcastle-Ottawa Scale (NOS) with 0 indicating the lowest and 9 as the highest score. Results were pooled using: (a) the standardized mean difference (SMD) for IL-6 levels which was considered statistically significant when the 0 value was not within the 95% confidence interval (CI), or (b) odds ratio (OR; 95% CI) through converting and pooling the IL-6 (-G174C) genotypes and alleles data into individual 2×2 tables. Heterogeneity was assessed based on I² values; where I²≤50% and I²>50% designated using fixed and random effect models, respectively.

RESULTS

Circulating IL-6 levels are higher in IBS patients compared to controls (SMD: 2.40 [95%CI: 0.53-4.28]; p=0.01). Categorizing data based on IBS subtypes, showed that IL-6 level is significantly higher in diarrhea predominant IBS (IBS-D) compared to control (SMD: 2.62 [95%CI: 0.29-4.95]; p=0.03), while it is comparable in constipation predominant IBS (IBS-C) and alternating IBS (IBS-A) patients with healthy controls. The meta-analysis of IL-6 (-G174C) polymorphism in IBS and based on IBS subtypes showed no difference in the distribution of genotypes or alleles compared to control.

CONCLUSION

The higher IL-6 levels in IBS and more specifically in IBS-D suggests a pro-inflammatory phenotype in these patients, while this phenomenon is not supported by the polymorphism of IL-6 (-G174C). Increased IL-6 in IBS might be an acquired phenomenon or mediated by other genotypes. Any potential association between gene polymorphisms and IL-6 levels in IBS should be tested by assessing both IL-6 levels and IL-6 (-G174C) simultaneously in the same IBS subjects compared to their healthy controls. Categorizing patients based on their circulating IL-6 levels may introduce a new opportunity for personalized anti-inflammatory therapies of IBS.

A double-blind, placebo-controlled study to assess the effect of a probiotic mixture on symptoms and inflammatory markers in women with diarrhea-predominant IBS

BACKGROUND

Micro-inflammation is considered an element in the pathogenesis of irritable bowel syndrome (IBS). High-sensitivity C reactive protein (hs-CRP) was previously shown to be higher in IBS compared to healthy controls, albeit within the normal range. Since probiotics may suppress micro-inflammation in the gut, we tested if they reduce symptoms and inflammatory markers (hs-CRP and fecal calprotectin (FC) in diarrhea-predominant IBS (IBS-D). The aim of this study was to assess the clinical and laboratory effects of BIO-25, a multispecies probiotic, in women with IBS-D.

METHODS

A double-blind, placebo-controlled study. Following a 2-week run-in, eligible women were assigned at random to a probiotic capsule or an indistinguishable placebo, twice daily for 8 weeks. IBS symptoms and stool consistency were rated daily by Visual Analogue Scales (VAS) and the Bristol Stool Scale (BSS). High-sensitivity C reactive protein was tested at baseline, 4 and 8 weeks. FC was tested at baseline and 8 weeks.

KEY RESULTS

One hundred and seventy-two IBS-D patients were recruited and 107 eligible patients were allocated to the intervention (n=54) or placebo (n=53) group. All symptoms improved in both groups with no significant difference between them in symptom improvement, hs-CRP or FC levels.

CONCLUSIONS & INFERENCES

An 8-week treatment with BIO-25 improved symptoms in women with IBS-D, but was not superior to placebo. This rigorously designed and executed study supports the findings of other studies that did not demonstrate superiority of probiotics over placebo in IBS. High quality clinical studies are necessary to examine the efficacy of other specific probiotics in IBS-D patients since data are still conflicting.

Prevalence and predictors of irritable bowel syndrome in patients with morbid obesity: a cross-sectional study

BACKGROUND

Irritable bowel syndrome has been reported as more common in patients with morbid obesity than in the general population. The reason for this association is unknown. The aims of this study were to study the prevalence of irritable bowel syndrome and other functional bowel disorders in patients with morbid obesity, and to search for predictors of irritable bowel syndrome.

METHODS

Patients opting for bariatric surgery at two obesity centers in South-Eastern Norway were included. Functional bowel disorders were diagnosed according to the Rome III criteria. Predictors were evaluated in a multivariable logistic regression analysis with irritable bowel syndrome as the dependent variable.

RESULTS

A total of 350 (58%) out of 603 consecutive patients were included. The prevalence rates of irritable bowel syndrome at the two centers were 17/211 (8%) and 37/139 (27%) respectively. High low-density lipoprotein (OR 2.10; 95% CI 1.34-3.29), self-reported psychiatric disorders (OR 2.39; 95% CI 1.12-5.08) and center (OR 5.22; 95% CI 2.48-10.99) were independent predictors of irritable bowel syndrome.

CONCLUSIONS

At one of the two obesity centers, the prevalence of irritable bowel syndrome was threefold higher than in the general population in the same region. The high prevalence appears to be related to dietary differences or altered absorption or metabolism of fat. Attention to irritable bowel syndrome is important in the care of patients with morbid obesity.

High-sensitive C-Reactive Protein as a Marker for Inflammation in Irritable Bowel Syndrome

BACKGROUND

Recent studies demonstrated low-grade inflammation in patients with irritable bowel syndrome (IBS). However, these studies have been relatively small and do not enable examination of this factor in different subtypes of IBS and the possibility of confounding effects of comorbidities that may be associated with inflammatory responses.

GOALS

To investigate the association between high-sensitive C-reactive protein (hs-CRP) and the diagnosis of IBS, IBS subtypes, symptoms' severity, and IBS-associated comorbidities.

STUDY

This cross-sectional study uses data from a large matched case-control study of IBS subjects and healthy controls (HC). hs-CRP levels were measured in all subjects. IBS diagnosis was determined by Rome III criteria, negative screening blood tests, and normal colonoscopy. Subjects were evaluated for IBS severity and associated pain and psychological comorbidities.

RESULTS

A total of 242 IBS patients and 244 HC were studied. Median hs-CRP levels in the IBS group were significantly higher than in HC (1.80; interquartile range, 0.7 to 4.04 mg/L vs. 1.20, interquartile range, 0.5 to 2.97 mg/L respectively, P<0.006). Levels were highest in IBS-D patients with greater disease severity. Hs-CRP levels mildly correlated with symptoms severity (r=0.169, P=0.009); this correlation was stronger for the IBS-D patients (r=0.27, P=0.006). IBS was a significant independent predictor (P=0.025) for higher hs-CRP levels, whereas other pain and psychological comorbidities were not.

CONCLUSIONS

Given these observations of cross-sectional differences in hs-CRP between IBS subtypes and severity, independent of pain and comorbidities, more research is needed to explore a possible role of low-grade inflammation in the pathogenesis and/or clinical presentation of IBS.

Immunological Biomarkers in Postinfectious Irritable Bowel Syndrome

BACKGROUND

There is a recognized need for biological markers to facilitate diagnoses of irritable bowel syndrome (IBS) and to distinguish it from other functional and organic disorders. As postinfectious IBS (PI-IBS) is believed to account for as many as one third of all IBS cases, here we sought to identify differences in specific cytokines and serologic responses across patients with idiopathic IBS and PI-IBS and healthy controls.

METHODS

At total of 120 US military personnel were identified from the Defense Medical Surveillance System-based International Classification of Diseases, 9th Revision, Clinical Modification (ICD9-CM) codes recorded during medical encounters and were grouped based on infectious gastroenteritis (IGE) episode (Shigella, Campylobacter, Salmonella, or an unspecified pathogen) followed by IBS, IBS without antecedent IGE, or IGE without subsequent IBS within 2 years of the IGE exposure. Sera from subjects were assayed for cytokine levels and antibodies against a panel of microbiome antigens.

RESULTS

In total, 10 of 118 markers considered were shown to differ between IBS patients and healthy controls, including cytokines interleukin-6 (IL-6), IL-8, IL-1β, and macrophage inflammatory protein-1β (MIP-1β), as well as antibody responses to microbial antigens. Antimicrobial antibody response profiles also differed between PI-IBS cases compared with IBS cases without an antecedent episode of acute IGE. Comparisons also suggest that immunoglobulin A (IgA) and IgG profiles may point to pathogen-specific origins among PI-IBS cases.

CONCLUSION

Taken together, these results provide further evidence as to the molecular distinctness of classes of IBS cases and that serum biomarkers may prove useful in elucidating their pathobiological pathways.

Diagnosis of Irritable Bowel Syndrome: Role of Potential Biomarkers

Irritable bowel syndrome is a disorder diagnosed on symptom-based criteria without inclusion of any objective parameter measurable by known diagnostic methods. Heterogeneity of the disorder and overlapping with more serious organic diseases increase uncertainty for the physician's work and increase the cost of confirming the diagnosis. This paper is an attempt to summarize the efforts to find adequate biomarkers for irritable bowel syndrome, which should shorten the time to diagnosis and reduce the cost. Most of the reviewed papers were observational studies from secondary care institutions. Since publication of the Rome III criteria in 2006, most recent studies use these for the recruitment of IBS patients. This is a positive step forward as future studies should use the same criteria, facilitating comparison of their results. Among the studied biomarkers, most evidence is provided for fecal calprotectin. Cutoff values for fecal calprotectin have still to be investigated prior to inclusion in the irritable bowel syndrome diagnostic algorithm.

Soluble mediators in plasma from irritable bowel syndrome patients excite rat submucosal neurons

BACKGROUND

Episodic bouts of abdominal pain and altered bowel habit are characteristic of irritable bowel syndrome (IBS). Although a comprehensive understanding of IBS pathophysiology remains elusive, support is growing for a primary role for immune activation in disease severity as evidenced by altered cytokine profiles in IBS plasma. Additionally, aberrant stimulation of the stress axis is likely to result in altered plasma constituents.

METHODS

Whole-mount preparations of submucosal plexus from adult male Sprague Dawley rats were exposed to plasma from IBS patients and healthy controls. Ratiometric calcium imaging recordings were used to measure changes in intracellular calcium ([Ca(2+)]i) as a marker of neuronal excitability.

KEY RESULTS

IBS plasma stimulated a robust increase in [Ca(2+)]i (0.09 ± 0.02) whereas plasma from healthy volunteers had little effect (-0.02 ± 0.02, n=24, p<0.001). The neuromodulatory actions of IBS plasma were reduced by pre-neutralisation with anti-interleukin (IL)-6 (p<0.01) but not IL-8, immunoglobulin G or C-reactive protein. Moreover, IBS plasma-evoked responses (0.22 ± 0.06) were inhibited by the corticotrophin releasing factor receptor (CRFR) 1 antagonist, antalarmin (1μM, 0.015 ± 0.02, n=14, p<0.05), but not the CRFR2 antagonist, astressin 2B. Neuronal activation was mediated by ERK/MAPK signalling.

CONCLUSIONS

These data provide evidence that factors present in IBS plasma modulate neuronal activity in the submucosal plexus and that this is likely to involve CRFR1 activation and IL-6 signalling. These neuromodulatory actions of stress and immune factors indicate a potential mechanism by which immune activation during periods of stress may lead to symptom flares in IBS.

Is fecal microbiota transplantation (FMT) an effective treatment for patients with functional gastrointestinal disorders (FGID)?

BACKGROUND

Despite its high prevalence and significant effect on quality of life, the etiology of functional gastrointestinal disorders (FGID), and specifically irritable bowel syndrome (IBS), has yet to be fully elucidated. While alterations in immunity, motility, and the brain-gut axis have been implicated in disease pathogenesis, the intestinal microbiota are increasingly being shown to play a role and numerous studies have demonstrated significant differences from normal in the intestinal flora of patients with FGID, and between types of FGID. Fecal microbiota transplantation (FMT) is a curative therapy for Clostridium difficile infection (CDI), a disease hallmarked by intestinal dysbiosis, and FMT is now being explored as a means to also restore intestinal homeostasis in FGID.

PURPOSE

This review aims to investigate the role of intestinal microbiota in the pathogenesis of FGID, the implications of FMT for the treatment of FGID, and the challenges encountered in measuring response to a specific intervention in patients with FGID.

Abdominal pain and the neurotrophic system in ulcerative colitis

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Intestinal microbiota and immune function in the pathogenesis of irritable bowel syndrome

The pathophysiology of irritable bowel syndrome (IBS) is believed to involve alterations in the brain-gut axis; however, the etiological triggers and mechanisms by which these changes lead to symptoms of IBS remain poorly understood. Although IBS is often considered a condition without an identified "organic" etiology, emerging evidence suggests that alterations in the gastrointestinal microbiota and altered immune function may play a role in the pathogenesis of the disorder. These recent data suggest a plausible model in which changes in the intestinal microbiota and activation of the enteric immune system may impinge upon the brain-gut axis, causing the alterations in gastrointestinal function and the clinical symptoms observed in patients with IBS. This review summarizes the current evidence for altered intestinal microbiota and immune function in IBS. It discusses the potential etiological role of these factors, suggests an updated conceptual model for the pathogenesis of the disorder, and identifies areas for future research.

The Crohn's disease activity index (CDAI) is similarly elevated in patients with Crohn's disease and in patients with irritable bowel syndrome

BACKGROUND

While the Crohn's disease activity index (CDAI) is the gold standard for defining clinical endpoints in Crohn's disease (Crohn's) clinical trials, its ability to distinguish symptoms due to inflammation from those that are non-inflammatory has been questioned.

AIM

To compare CDAI scores in patients with Crohn's and those with Irritable Bowel Syndrome (IBS).

METHODS

This was a prospective, cross-sectional cohort study of 91 patients with either Crohn's (n = 44) or IBS (n = 47). Total CDAI and individual component scores were recorded and comparisons were made between Crohn's and IBS patients.

RESULTS

Mean CDAI scores were higher in the IBS patients (183 vs. 157, P = 0.1). Sixty-two per cent (n = 29) of IBS patients had CDAI scores greater than 150. Mean CDAI haematocrit score (35.9 vs. 23.0, P = 0.02) and CRP level (6.8 vs. 2.0, P = 0.002) were higher in the Crohn's group. Analysis of CDAI sub-scores demonstrated that IBS patients had significantly higher pain (mean 1.7 vs. 0.8, P = 0.0007) and well-being scores (mean 1.2 vs. 0.8, P = 0.04) relative to patients with Crohn's. Specifically evaluating patients with CDAI greater than 150 (n = 51), IBS patients had higher pain sub-scores (mean 2.4 vs. 1.4, P = 0.002), whereas patients with Crohn's had higher CRP (mean 8.4 vs. 1.8, P = 0.001).

CONCLUSIONS

Our study demonstrates that the CDAI does not discriminate patients with symptoms due to active Crohn's from patients with IBS. Patients with IBS can have CDAI scores in the clinically meaningful range. Objective measures, such as CDAI haematocrit score and CRP, are more specific markers of inflammation.

Experimental endotoxemia as a model to study neuroimmune mechanisms in human visceral pain

The administration of bacterial endotoxin (i.e., lipopolysaccharide, LPS) constitutes a well-established experimental approach to study the effects of an acute and transient immune activation on physiological, behavioral, and emotional aspects of sickness behavior in animals and healthy humans. However, little is known about possible effects of experimental endotoxemia on pain in humans. This knowledge gap is particularly striking in the context of visceral pain in functional as well as chronic-inflammatory gastrointestinal disorders. Although inflammatory processes have been implicated in the pathophysiology of visceral pain, it remains incompletely understood how inflammatory mediators interact with bottom-up (i.e., increased afferent input) and top-down (i.e., altered central pain processing) mechanisms of visceral hyperalgesia. Considering the recent findings of visceral hyperalgesia after LPS application in humans, in this review, we propose that experimental endotoxemia with its complex peripheral and central effects constitutes an experimental model to study neuroimmune communication in human pain research. We summarize and attempt to integrate relevant animal and human studies concerning neuroimmune communication in visceral and somatic pain, discuss putative mechanisms, and conclude with future research directions.