Fecal assays detect hypersensitivity to cow's milk protein and gluten in adults with irritable bowel syndrome

Fecal calprotectin levels in patients with non-celiac wheat sensitivity: a proof of concept

Some data suggest the existence of intestinal inflammation in patients with non-celiac wheat sensitivity (NCWS). We aimed to verify whether fecal calprotectin (FCP), a marker of intestinal inflammation, could be used to confirm this inflammatory status and to test its diagnostic performance in differentiating NCWS from irritable bowel syndrome/functional dyspepsia (IBS/FD). We conducted a multicenter study, comparing NCWS patients, diagnosed by a double-blind placebo-controlled wheat challenge, with IBS/FD subjects. In the retrospective phase, FCP values were analyzed to define the prevalence of its positivity and its role as a NCWS diagnostic biomarker. In the prospective phase we tested the effects of a strict 6-month wheat-free diet (WFD) on FCP values. 31.3% (n = 63/201) of NCWS patients had above normal FCP values (NCWS FCP +), whereas all IBS/FD patients proved negative (P = 0.0001). FCP using a cut-off value > 41 µg/g showed a 58.6% sensitivity and a 98.0% specificity (AUC 0.755, 95% C.I. 0.702-0.837) in distinguishing NCWS from IBS/FD patients. Of the 63 NCWS FCP+, 65.1% had negative FCP values after ≥ 6 months of WFD, with a significant reduction in FCP values (P < 0.0001). All NCWS FCP- subjects still preserved negative FCP values after ≥ 6 months of WFD. Our study showed that FCP can be a useful but supplementary diagnostic marker for differentiating between NCWS and IBS/FD. Strict WFD adherence reduced FCP values, normalizing them in 65.1% of NCWS FCP + subjects. These data suggest the existence of two NCWS subgroups: NCWS FCP + characterized by a probable predominantly inflammatory/immunologic pattern and NCWS FCP- featuring non-immuno-mediated etiopathogenetic mechanisms. (Registration number NCT01762579).

Emerging Role of Alarmins in Food Allergy: An Update on Pathophysiological Insights, Potential Use as Disease Biomarkers, and Therapeutic Implications

Food allergies are immuno-mediated adverse reactions to ingestion or contact with foods, representing a widespread health problem. The immune response can be IgE-mediated, non-IgE-mediated, or with a mixed mechanism. The role of innate immunity and alarmins in the pathogenesis of diseases such as asthma and atopic dermatitis is well known. Some authors have investigated the correlation between alarmins and food allergies, often obtaining interesting results. We analyzed articles published in English from the last 22 years present on PubMed concerning the role of alarmins in the pathogenesis of food allergies and their potential use as disease biomarkers, response biomarkers to therapy, or potential therapeutic targets. Nuclear alarmins (TSLP, IL-33, IL-25) appear to have a critical role in IgE-mediated allergies but are also implicated in entities such as eosinophilic esophagitis. Calprotectin and defensins may play a role as disease biomarkers and could help predict response to therapy, although results in the literature are often conflicting. Despite the promising results, more studies on humans still need to be conducted. Deepening our knowledge regarding alarmins and their involvement in food allergies could lead to the development of new biological therapies, significantly impacting patients' quality of life.

Is it time to rethink the burden of non-coeliac gluten sensitivity? A systematic review

INTRODUCTION

Non-coeliac gluten sensitivity (NCGS) is still a poorly defined clinical condition. This review aims to describe the clinical features of subjects with a symptomatic response to gluten intake, and to estimate the prevalence of NCGS.

EVIDENCE ACQUISITION

Literature search was conducted in accordance with PRISMA recommendations. The PubMed database was searched for original articles until 1^st June 2020.

EVIDENCE SYNTHESIS

We identified 30 relevant articles, including 14 studies that investigated NCGS through a double-blind, placebo-controlled crossover trial (DBPCC), and 16 that examined the role of gluten in causing symptoms without a DBPCC. We found that regardless of the diagnostic work up, gluten-sensitive patients were predominately middle-aged females complaining of abdominal pain, bloating and diarrhea. The pooled prevalence of NCGS after DBPCC was 24% (5-34%). Subjects with irritable bowel syndrome or self-reporting gluten intolerance accounted for the vast majority of the patients who did not start a DBPCC. A symptomatic response to a gluten-free diet (GFD) occurred in between 7% and 93% of patients. No data on long-term outcomes of NCGS individuals were reported.

CONCLUSIONS

Clinical features of NCGS patients did not differ among all the included studies, whereas prevalence figures are rather heterogeneous. Long-term benefit of a GFD on these patients still needs to be ascertained.

Cow’s milk-induced gastrointestinal disorders: From infancy to adulthood

Milk is related to many gastrointestinal disorders from the cradle to the grave due to the many milk ingredients that can trigger gastrointestinal discomfort and disorders. Cow’s milk protein allergy (CMPA) is the most common food allergy, especially in infancy and childhood, which may persist into adulthood. There are three main types of CMPA; immunoglobulin E (IgE)-mediated CMPA, non-IgE-mediated CMPA, and mixed type. CMPA appears before the first birthday in almost all cases. Symptoms may start even during the neonatal period and can be severe enough to simulate neonatal sepsis. CMPA (often non-IgE mediated) can present with symptoms of gastroesophageal reflux, eosinophilic esophagitis, hemorrhagic gastritis, food protein-induced protein-losing enteropathy, and food protein-induced enterocolitis syndrome. Most CMPAs are benign and outgrown during childhood. CMPA is not as common in adults as in children, but when present, it is usually severe with a protracted course. Lactose intolerance is a prevalent condition characterized by the development of many symptoms related to the consumption of foods containing lactose. Lactose intolerance has four typical types: Developmental, congenital, primary, and secondary. Lactose intolerance and CMPA may be the underlying pathophysiologic mechanisms for many functional gastrointestinal disorders in children and adults. They are also common in inflammatory bowel diseases. Milk consumption may have preventive or promoter effects on cancer development. Milk may also become a source of microbial infection in humans, causing a wide array of diseases, and may help increase the prevalence of antimicrobial resistance. This editorial summarizes the common milk-related disorders and their symptoms from childhood to adulthood.

A Non-Invasive Neonatal Signature Predicts Later Development of Atopic Diseases

Background: Preterm birth is a major cause of morbidity and mortality in infants and children. Non-invasive methods for screening the neonatal immune status are lacking. Archaea, a prokaryotic life domain, comprise methanogenic species that are part of the neonatal human microbiota and contribute to early immune imprinting. However, they have not yet been characterized in preterm neonates. Objective: To characterize the gut immunological and methanogenic Archaeal (MA) signature in preterm neonates, using the presence or absence of atopic conditions at the age of one year as a clinical endpoint. Methods: Meconium and stool were collected from preterm neonates and used to develop a standardized stool preparation method for the assessment of mediators and cytokines and characterize the qPCR kinetics of gut MA. Analysis addressed the relationship between immunological biomarkers, Archaea abundance, and atopic disease at age one. Results: Immunoglobulin E, tryptase, calprotectin, EDN, cytokines, and MA were detectable in the meconium and later samples. Atopic conditions at age of one year were positively associated with neonatal EDN, IL-1β, IL-10, IL-6, and MA abundance. The latter was negatively associated with neonatal EDN, IL-1β, and IL-6. Conclusions: We report a non-invasive method for establishing a gut immunological and Archaeal signature in preterm neonates, predictive of atopic diseases at the age of one year.

The prevalence and risk factors of irritable bowel syndrome in Saudi Arabia in 2019

Background:

Irritable bowel syndrome (IBS) is a common chronic functional gastrointestinal (GI) disorder. The aim of this study is to assess the prevalence of IBS and its risk factors among the general population of Saudi Arabia, as there is no previous study has done so.

Methods:

A cross-sectional study was carried out to evaluate the prevalence of IBS, IBS subtypes and IBS risk factors among the general population of Saudi Arabia from June 22 to November 30, 2019. A designed questionnaire that is based on ROME IV criteria and licensed from Rome Foundation was used. A total of 1,680 eligible individuals from different parts of Saudi Arabia took part in this national survey and were included in the statistical analysis. The statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) program (version 22).

Results:

The prevalence of IBS in the study was 18.2%. IBS-M was the most common subtype among IBS patients (42.3%). Risk factors that are significantly associated with IBS were shown to be smoking habits, gastroesophageal reflux disease (GERD), food allergy, anxiety, psychological stress, family history of IBS, regular use of non-steroidal anti-inflammatory drugs (NSAIDs), history of infection before occurrence of symptoms and residence in the south of Saudi Arabia (P < 0.05*).

Conclusions:

IBS is prevalent in Saudi Arabia. The most common risk factor among IBS patients is a positive family history of IBS (80%). Raising public awareness and further prospective studies are both advocated and needed.

Elevated F-EDN correlates with mucosal eosinophil degranulation in patients with IBS-A possible association with microbiota?

Eosinophils have been linked to functional dyspepsia; however, less is known about their role in irritable bowel syndrome (IBS). This study tested the hypothesis of alterations in levels of fecal eosinophil-derived neurotoxin (F-EDN) and eosinophil density and degranulation within the colonic mucosa of IBS patients compared with healthy controls (HC). Colonic biopsies were collected from 37 IBS patients and 20 HC and analyzed for eosinophil numbers and local degranulation of eosinophil cationic protein (ECP) by histologic procedures. Fecal samples were collected for F-EDN and microbiota analysis. Differentiated 15HL-60 cells were used in vitro to investigate the direct effect of live bacteria on eosinophil activation measured by a colorimetric assay with o-phenylenediamine (OPD) substrate. We observed a higher number of eosinophils and increased extracellular ECP in the mucosa of IBS patients compared with HC. Moreover, F-EDN levels in IBS samples were elevated compared with HC and positively correlated to extracellular ECP. Metagenomic analysis showed significant correlations between bacterial composition and eosinophil measurements in both HC and IBS patients. In vitro experiments revealed an increased degranulation of 15HL-60 after stimulation with Salmonella typhimurium, Salmonella enterica, and Yersinia enterocolitica. To conclude, we could demonstrate alterations related to eosinophils in IBS, and, for the first time, a positive correlation between F-EDN levels and degranulated eosinophils in the colonic mucosa of IBS patients. Together our results suggest that eosinophils play a role in the pathophysiology of IBS and the mechanisms might be linked to an altered microbiota.

Noninvasive and minimally invasive techniques for the diagnosis and management of allergic diseases

Allergic diseases of the (upper and lower) airways, the skin and the gastrointestinal tract, are on the rise, resulting in impaired quality of life, decreased productivity, and increased healthcare costs. As allergic diseases are mostly tissue-specific, local sampling methods for respective biomarkers offer the potential for increased sensitivity and specificity. Additionally, local sampling using noninvasive or minimally invasive methods can be cost-effective and well tolerated, which may even be suitable for primary or home care sampling. Non- or minimally invasive local sampling and diagnostics may enable a more thorough endotyping, may help to avoid under- or overdiagnosis, and may provide the possibility to approach precision prevention, due to early diagnosis of these local diseases even before they get systemically manifested and detectable. At the same time, dried blood samples may help to facilitate minimal-invasive primary or home care sampling for classical systemic diagnostic approaches. This EAACI position paper contains a thorough review of the various technologies in allergy diagnosis available on the market, which analytes or biomarkers are employed, and which samples or matrices can be used. Based on this assessment, EAACI position is to drive these developments to efficiently identify allergy and possibly later also viral epidemics and take advantage of comprehensive knowledge to initiate preventions and treatments.

Does a Minority of Children With Functional Gastrointestinal Disorders Receive Formal Diet Advice?

BACKGROUND

Diet therapies may be recommended for pediatric functional gastrointestinal disorders (FGIDs). However, little is known about the frequency with which diet therapy is recommended in FGIDs. Our aims were to determine and contrast the frequency and types of diet recommendations provided to children with FGIDs by pediatric gastroenterologists (PGIs) versus primary care pediatricians (PCPs).

METHODS

A retrospective chart review was performed using data from a large, metropolitan children's academic healthcare system to identify subjects meeting Rome IV criteria for functional abdominal pain, functional dyspepsia, irritable-bowel syndrome (IBS), and/or abdominal migraine over a period of 23 months.

RESULTS

Of 1929 patient charts reviewed, 268 were included for further analyses. Of these, 186 patients (69%) were seen by a PGI and 82 (31%) by a PCP. The most common diagnosis was IBS (49% for PGIs and 71% for PCPs). Diet recommendations were provided to 115 (43%) patients (PGI group: 86 [75%] vs PCP group: 29 [25%]; P < .1). The most frequent recommendations were high fiber (PGI: 15%; PCP: 14%) and low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) diet (PGI: 12%; PCP: 4%). Of those provided with diet recommendations, only 20% (n = 23) received an educational consult by a dietitian. Provision of diet recommendations was not affected by years in practice.

CONCLUSION

Despite increasing awareness of the role of diet in the treatment of childhood FGIDs, a minority of patients receive diet recommendations in tertiary care or primary care settings. When diet recommendations were given, there was great variability in the guidance provided.

Factors associated with irritable bowel syndrome among medical students at Ain Shams University

BACKGROUND

Irritable bowel syndrome (IBS) is one of the most common and potentially disabling gastrointestinal disorders. The pathogenesis of this disorder remains obscure. However, many etiological explanations point toward bacterial etiology. Also, several studies have documented that psychological and social factors may play a role. Medical education is among the most challenging and stressful education, and this may predispose to high rates of IBS.

OBJECTIVES

The aims of this study are to estimate the frequency of IBS in a selected sample of students of Faculty of Medicine in Ain Shams University and to find out the determinants associated with this disorder.

STUDY DESIGN

A cross-sectional study was carried out among medical students from October 2017 to February 2018 at Faculty of Medicine-Ain Shams University. All participants were asked to complete a confidential self-administered questionnaire. An interview questionnaire was used for diagnosis of IBS according to Rome III criteria, while morbid anxiety and depression were diagnosed by using the Arabic version of Hospital Anxiety and Depression Scale (HADS).

RESULTS

Three hundred eighty-two students completed the questionnaire. The frequency of IBS was 31.7% with higher proportion among females and among students with positive family history of IBS. However, IBS was significantly less prevalent among students practicing regular exercise. Lastly, based on (HADS), there was a statistical significant relationship between IBS and anxiety (p < 0.05), but not depression.

CONCLUSION

The study revealed that around 31% of the studied group was suffering from IBS. Female gender, suffering from anxiety, and positive family history of IBS were the main associated factors for IBS. Screening of all medical students in the faculty for IBS is suggested. Providing psychological and emotional support along with stress management is highly recommended.

Fecal Eosinophil Cationic Protein Is a Diagnostic and Predictive Biomarker in Young Adults with Inflammatory Bowel Disease

BACKGROUND AND AIMS

Fecal biomarkers are important non-invasive markers monitoring disease activity in inflammatory bowel disease (IBD). We compared the significance of fecal eosinophil cationic protein (fECP) and fecal calprotectin (fCal).

METHODS

fECP and fCal were measured in patients with Crohn's disease (CD, n = 97), ulcerative colitis (UC, n = 53), Clostridioides difficile infection (CDI, n = 9), primary food allergy (PFA, n = 11), pollen-associated food allergy (n = 25) and non-inflammatory controls (n = 78). Results were correlated with clinical and endoscopic IBD activity scores.

RESULTS

fECP was significantly elevated in CD, UC, CDI and PFA compared to controls. fCal was significantly increased in CD, UC and CDI. fECP had lower diagnostic accuracy than fCal (area under the curve (AUC) = 0.88) in differentiating between endoscopically active and inactive patients with IBD (AUC = 0.77, ROC analysis). In contrast to fCal, fECP correlated negatively with age and levels were also elevated in clinically and endoscopically inactive patients with IBD <45 years (endoscopically inactive IBD vs controls; AUC for fECP = 0.86; AUC for fCal = 0.62). However, in those patients with low inflammatory activity (fCal <250 mg/kg), high fECP indicated the need for treatment modification or surgery (fECP <200 µg/kg = 22%; 200-600 µg/kg = 44%; >600 µg/kg = 82%) at month 48 of follow-up.

CONCLUSIONS

fECP is a diagnostic and prognostic marker in young patients with IBD in remission.

Non-Celiac Gluten Sensitivity: A Review

Background and objectives: Grain food consumption is a trigger of gluten related disorders: celiac disease, non-celiac gluten sensitivity (NCGS) and wheat allergy. They demonstrate with non-specific symptoms: bloating, abdominal discomfort, diarrhea and flatulence. Aim: The aim of the review is to summarize data about pathogenesis, symptoms and criteria of NCGS, which can be helpful for physicians. Materials and Methods: The PubMed and Google Scholar databases were searched in January 2019 with phrases: 'non-celiac gluten sensitivity', non-celiac gluten sensitivity', non-celiac wheat gluten sensitivity', non-celiac wheat gluten sensitivity', and gluten sensitivity'. More than 1000 results were found. A total of 67 clinical trials published between 1989 and 2019 was scanned. After skimming abstracts, 66 articles were chosen for this review; including 26 clinical trials. Results: In 2015, Salerno Experts' Criteria of NCGS were published. The Salerno first step is assessing the clinical response to gluten free diet (GFD) and second is measuring the effect of reintroducing gluten after a period of treatment with GFD. Several clinical trials were based on the criteria. Conclusions: Symptoms of NCGS are similar to other gluten-related diseases, irritable bowel syndrome and Crohn's disease. With Salerno Experts' Criteria of NCGS, it is possible to diagnose patients properly and give them advice about nutritional treatment.

Duodenal and Rectal Mucosa Inflammation in Patients With Non-celiac Wheat Sensitivity

BACKGROUND & AIMS

Studies of non-celiac gluten or wheat sensitivity (NCGWS) have increased but there are no biomarkers of this disorder. We aimed to evaluate histologic features of colon and rectal tissues from patients with NCGWS.

METHODS

We performed a prospective study of 78 patients (66 female; mean age, 36.4 years) diagnosed with NCGWS by double-blind wheat challenge at 2 tertiary care centers in Italy, from January 2015 through September 2016. Data were also collected from 55 patients wither either celiac disease or self-reported NCGWS but negative results from the wheat-challenge test (non-NCGWS controls). Duodenal and rectal biopsies were collected and analyzed by immunohistochemistry to quantify intra-epithelial CD3⁺ T cells, lamina propria CD45⁺ cells, CD4⁺ and CD8⁺ T cells, mast cells, and eosinophils and to determine the presence and size of lymphoid nodules in patients with NCGWS vs patients with celiac disease or non-NCGWS controls.

RESULTS

Duodenal tissues from patients with NCGWS had significantly higher numbers of intra-epithelial CD3⁺ T cells, lamina propria CD45⁺ cells, and eosinophils than duodenal tissues from non-NCGWS controls. Duodenal tissues from patients with NCGWS and dyspepsia had a higher number of lamina propria eosinophils than patients with NCGWS without upper digestive tract symptoms. Rectal mucosa from patients with NCGWS had a larger number of enlarged lymphoid follicles, intra-epithelial CD3⁺ T cells, lamina propria CD45⁺ cells, and eosinophils than rectal mucosa from non-NCGWS controls. Duodenal and rectal mucosal tissues from patients with celiac disease had more immunocytes (CD45⁺ cells, CD3⁺ cells, and eosinophils) than tissues from patients with NCGWS or non-NCGWS controls.

CONCLUSIONS

We identified markers of inflammation, including increased numbers of eosinophils, in duodenal and rectal mucosa from patients with NCGWS. NCGWS might therefore involve inflammation of the entire intestinal tract. Eosinophils could serve as a biomarker for NCGWS and be involved in its pathogenesis. Clinicaltrials.gov: NCT01762579.

An integrative review of dietetic and naturopathic approaches to functional bowel disorders

OBJECTIVES

Naturopathy and dietetics have evolved as two separate but parallel professions that use diet to promote optimal health and manage many illnesses and diseases. Given the increasing recognition of the influence of diet on health outcomes, there is increasing demand for the services of both professions. The aim of this research was to investigate similarities and differences between naturopathic and dietetic approaches to functional bowel disorders (FBDs).

DESIGN

For this integrative review AMED, CINAHL, the Cochrane Database of Systematic Reviews, EMBASE, Medline and PubMed databases were searched for articles that focused on dietetic or naturopathic diagnosis and treatment of food intolerance expressing as a FBD in adults. (Registration: PROSPERO 2016 CRD42016049469).

RESULTS

Of the 55 papers in the final review, 10 discussed complementary medicine approaches to FBDs. Both dietitians and naturopaths used similar holistic approaches to diagnosis and treatment, adjusted diets as a primary treatment approach, and individualised treatment for their patients. The professions differed in their use of vitamin, mineral and herbal supplements and in their willingness to recommend other treatments like osteopathy and acupuncture.

CONCLUSIONS

There is much overlap between dietetic and naturopathic approaches to assessment and treatment of FBDs. Further publications that describe naturopathic treatments for FBDs are needed to confirm these results and to provide opportunities for increased recognition and scrutiny of any distinctively naturopathic approaches. Without doing so, naturopathic practices are likely to remain marginalised and poorly understood. Moreover, the opportunity to fully contribute to the management of lifestyle-related diseases will be missed.

Upregulation of calprotectin in mild IgE-mediated ovalbumin hypersensitivity

Calprotectin, also known as S100A8/A9, has been linked to gut inflammation caused by IgE-mediated food hypersensitivities, but the pathophysiologic abnormalities it causes remain to be determined. We created a mild food hypersensitivity model through oral gavage of ovalbumin in Norway brown rats without using immune adjuvant. Changes in the levels of calprotectin and inflammation-associated cytokines were then observed over time. We found that fecal calprotectin as well as jejunal and liver TLR4, TNF-α, NF-κB, IL-1β, and IL-6 were upregulated in hypersensitive rats. Additionally, the influence of calprotectin on CD4⁺ T and dendritic cells was observed by co-culturing CD4⁺ T cells with dendritic cells, which revealed a shift toward increased Th2 T cells in calprotectin-treated cultures. These results suggest that calprotectin, along with other inflammatory factors, promotes the inflammation seen in mild food allergy.

Suspected Nonceliac Gluten Sensitivity Confirmed in Few Patients After Gluten Challenge in Double-Blind, Placebo-Controlled Trials

A double-blind, placebo-controlled, gluten challenge has been proposed to confirm a diagnosis of nonceliac gluten sensitivity (NCGS) in patients without celiac disease who respond to a gluten-free diet. To determine the accuracy of this approach, we analyzed data from 10 double-blind, placebo-controlled, gluten-challenge trials, comprising 1312 adults. The studies varied in the duration of the challenge (range, 1 d to 6 wk), daily doses for the gluten challenge (range, 2-52 g; 3 studies administered <8 g/d), and composition of the placebo (gluten-free products, xylose, whey protein, rice, or corn starch containing fermentable carbohydrates). Most of the studies found gluten challenge to significantly increase symptom scores compared with placebo. However, only 38 of 231 NCGS patients (16%) showed gluten-specific symptoms. Furthermore, 40% of these subjects had a nocebo response (similar or increased symptoms in response to placebo). These findings reveal heterogeneity and potential methodology flaws among studies of gluten challenge, cast doubt on gluten as the culprit food component in most patients with presumptive NCGS, and highlight the importance of the nocebo effect in these types of studies.

Pathophysiology, Evaluation, and Management of Chronic Watery Diarrhea

Chronic watery diarrhea poses a diagnostic and therapeutic challenge and is often a disabling condition for patients. Although acute diarrhea is likely to be caused by infection, the causes of chronic diarrhea (>4 weeks in duration) are more elusive. We review the pathophysiology, diagnosis, and treatment of chronic diarrhea. Drawing on recent insights into the molecular mechanisms of intestinal epithelial transport and barrier function, we discuss how diarrhea can result from a decrease in luminal solute absorption, an increase in secretion, or both, as well as derangements in barrier properties. We also describe the various extraepithelial factors that activate diarrheal mechanisms. Finally, clinical evaluation and tests used in the assessment of patients presenting with chronic diarrhea are reviewed, and an algorithm guiding therapeutic decisions and pharmacotherapy is presented.

Evaluation of an online “teachable moment” dietary intervention

Purpose

The purpose of this paper is to evaluate an online “teachable moment” intervention to promote healthy eating for overweight and food intolerance symptoms.

Design/methodology/approach

The study involves a 2×2 factorial design with two conditions: group (weight loss vs food intolerance) and condition (intervention vs control). The intervention aimed to generate a “teachable moment” by providing knowledge regarding the relationship between food and the problem (overweight or food intolerance), focussing on the negative aspects of the problem, creating a behavioural model, and encouraging hope and reinvention. Participants receiving the intervention (n=22) completed measures of dietary behaviour and either weight or food intolerance symptoms before receiving the intervention and again one month later. Control participants (n=20) provided measures but did not receive the intervention.

Findings

There were no significant reductions in weight or food intolerance symptoms. However, compared to control participants, participants in the intervention conditions reported greater intentions to eat healthily (p=0.01) and improved healthy eating behaviour over time, following both an intention-to-treat (p=0.046) and explanatory analysis (p=0.042).

Practical implications

Encouraging individuals to perceive their everyday situation as a time for change and adopt healthier behaviour early on, may prevent future diet-related medical events. This has benefits for both the individual and for health care costs.

Originality/value

A quick and easy-to-administer online “teachable moment” intervention improves dietary behaviour and can be minimally adapted to suit individuals with differing health needs.

Irritable Bowel Syndrome: A Global Challenge Among Medical Students

Irritable bowel syndrome (IBS) has been identified as one of the more highly prevalent and costly gastrointestinal disorders. Despite its uncertain etiology, risk factors, such as stress and academic load, are well correlated with the prevalence of the disease. Being in one of the most stressful and challenging environments, medical students are predisposed to have high rates of IBS. The socioeconomic burden of the disease on its sufferers is devastating as their quality of life is reduced, mandating additional health care precautions. The aim of this article, therefore, is to review the current literature about IBS among medical students, its prevalence, associated risk factors, and diagnostic criteria. Additionally, different solutions and management options are recommended to control the disease.

Faecal eosinophil cationic protein and serum immunoglobulin E in relation to infant feeding practices

Background To date, the effects of exclusive breastfeeding duration and timing of solid food introduction on allergy prevention are unclear. The aim of this study was to determine the effect of variable feeding practices on intestinal inflammation in infants using faecal eosinophil cationic protein as a surrogate marker and to assess whether faecal eosinophil cationic protein is associated with serum immunoglobulin E. Methods Subjects ( n = 206) were enrolled from the Prediction of Allergies in Taiwanese CHildren (PATCH) birth cohort study. Stool samples were collected at 6 and 12 months for determining eosinophil cationic protein, and blood was collected for determining total and allergen-specific immunoglobulin E at 12 months. We compared these biomarkers between infants with variable exclusive breastfeeding duration and infants introduced to solid foods at various periods. The association between faecal eosinophil cationic protein, total serum immunoglobulin E and specific immunoglobulin E was also analysed. Results Faecal eosinophil cationic protein was significantly higher in exclusively breastfed infants compared with formula-fed infants and infants who were not exclusively breastfed at 6 months of age ( P < 0.05). At 12 months, infants who were introduced to solid foods at 5-6 months had the lowest faecal eosinophil cationic protein compared with those who were introduced at earlier and later periods. There was no significant association between faecal eosinophil cationic protein and serum immunoglobulin E. Conclusion We found that breastfeeding exclusively for >6 months did not reduce serum immunoglobulin E, but rather increased intestinal inflammation. Faecal eosinophil cationic protein was not associated with total serum immunoglobulin E and specific immunoglobulin E and might not be a useful indictor of immunoglobulin E sensitization in infancy.

Irritable bowel syndrome among nurses working in King Abdulaziz University Hospital, Jeddah, Saudi Arabia

BACKGROUND

Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder that can cause disability and economic burden. Nurses are a vital part of the medical team and their well-being is an important issue. Yet, few studies have been done concerning IBS among nurses.

OBJECTIVES

To determine the prevalence, severity, and predictors of IBS among nurses working at King Abdulaziz University Hospital, Jeddah, Saudi Arabia.

MATERIALS AND METHODS

A cross-sectional study was conducted among 229 nurses who fulfilled the eligibility criteria. They were selected by stratified random sampling during 2014-2015. A validated, confidential, self-administered data collection sheet was used for collection of personal and sociodemographic data. Rome III Criteria, IBS Severity Scoring System (IBS-SSS), Hospital Anxiety and Depression Scale (HADS), and Pittsburgh Sleep Quality Index (PSQI) were included. Both descriptive and inferential statistics were done. A multiple logistic regression analysis was done to determine the predictors of IBS.

RESULTS

The prevalence of IBS among nurses was 14.4%, and IBS-Mixed type was the commonest variety (54.5%). Positive family history of IBS, working in outpatient clinics, having day shift, poor sleep quality, and high anxiety and depression scale scores were significantly associated with IBS. After controlling for confounding factors in regression analysis, the predictors of IBS were food hypersensitivity (aOR=4.52; 95% CI: 1.80-11.33), morbid anxiety (aOR=4.34; 95% CI: 1.49-12.67), and positive family history of IBS (aOR=3.38; 95% CI: 1.12-13.23).

CONCLUSION

The prevalence of IBS was 14.4%. Food hypersensitivity, morbid anxiety, and family history were the predictors of IBS. Screening and management of IBS, food hypersensitivity, and psychological problems among nurses are recommended.

Sensitivity to wheat, gluten and FODMAPs in IBS: facts or fiction?

IBS is one of the most common types of functional bowel disorder. Increasing attention has been paid to the causative role of food in IBS. Food ingestion precipitates or exacerbates symptoms, such as abdominal pain and bloating in patients with IBS through different hypothesised mechanisms including immune and mast cell activation, mechanoreceptor stimulation and chemosensory activation. Wheat is regarded as one of the most relevant IBS triggers, although which component(s) of this cereal is/are involved remain(s) unknown. Gluten, other wheat proteins, for example, amylase-trypsin inhibitors, and fructans (the latter belonging to fermentable oligo-di-mono-saccharides and polyols (FODMAPs)), have been identified as possible factors for symptom generation/exacerbation. This uncertainty on the true culprit(s) opened a scenario of semantic definitions favoured by the discordant results of double-blind placebo-controlled trials, which have generated various terms ranging from non-coeliac gluten sensitivity to the broader one of non-coeliac wheat or wheat protein sensitivity or, even, FODMAP sensitivity. The role of FODMAPs in eliciting the clinical picture of IBS goes further since these short-chain carbohydrates are found in many other dietary components, including vegetables and fruits. In this review, we assessed current literature in order to unravel whether gluten/wheat/FODMAP sensitivity represent 'facts' and not 'fiction' in IBS symptoms. This knowledge is expected to promote standardisation in dietary strategies (gluten/wheat-free and low FODMAP) as effective measures for the management of IBS symptoms.

Noncoeliac gluten sensitivity: a diagnostic dilemma

PURPOSE OF REVIEW

Noncoeliac gluten sensitivity (NCGS) has gained attention as an emerging clinical entity. Data regarding the epidemiology, pathogenesis, and management of NCGS are scattered in view of the diagnostic uncertainty surrounding the disorder. We aim to provide a current perspective of NCGS and its associated controversies.

RECENT FINDINGS

NCGS consists of a spectrum of intestinal and extraintestinal symptoms related to the ingestion of gluten-containing food, yet in the absence of coeliac disease or wheat allergy. To date, no specific biomarker exists for NCGS, thereby leaving the diagnosis to be confirmed by dietary elimination followed by double-blind placebo-controlled gluten-based rechallenges. Unfortunately, this technique is cumbersome, not readily-available in routine clinical practise, and can still leave the diagnosis of NCGS open to debate as to whether the effects demonstrated can be specifically attributed to the gluten-protein per se or rather coexisting nongluten components, such as fermentable carbohydrates and amylase-trypsin inhibitors.

SUMMARY

Physicians are increasingly being posed with the dilemma of patients presenting with self-reported NCGS. However, this appears to be the tip of the iceberg and future studies are in need of delineating which gluten-based component is responsible for each individual patient's complaint.

The spectrum of noncoeliac gluten sensitivity

The past 5 years have seen an increase in the use of a gluten-free diet outside a diagnosis of coeliac disease or IgE-mediated wheat allergy. This trend has led to the identification of a new clinical entity termed noncoeliac gluten sensitivity (NCGS). In this Review, we discuss the evidence for NCGS as demonstrated by the results of double-blind, placebo-controlled dietary rechallenge studies. Furthermore, the characteristic phenotype of individuals with NCGS is described as well as the symptom manifestations commonly reported after gluten exposure, which include intestinal symptoms consistent with IBS, and extraintestinal symptoms such as neurological dysfunction, psychological disturbances, fibromyalgia and skin rash. Moreover, emerging evidence suggests that NCGS can be associated with organic gastrointestinal pathologies, such as IBD, in which its presence might be a reflection of severe or stricturing disease. However, NCGS is not without its controversies and uncertainties, in particular pertaining to whether it is gluten or nongluten components of the grain evoking symptoms; evidence suggests that fermentable carbohydrates, amylase trypsin inhibitors and wheat-germ agglutinin can also be responsible culprits. Finally, we discuss the novel techniques that might help diagnose NCGS in the future.

The Effect of Dietary Intervention on Irritable Bowel Syndrome: A Systematic Review

OBJECTIVES

Elimination diets have been used for many years to treat irritable bowel syndrome (IBS). These approaches had fallen out of favor until a recent resurgence, which was based on new randomized controlled trial (RCT) data that suggested it might be effective. The evidence for the efficacy of dietary therapies has not been evaluated systematically. We have therefore conducted a systematic review to examine this issue.

METHODS

MEDLINE, EMBASE, and the Cochrane Controlled Trials Register were searched up to December 2013. Trials recruiting adults with IBS, which compared any form of dietary restriction or addition of an offending food group in patients already on a restricted diet vs. placebo, control therapy, or "usual management", were eligible. Dichotomous symptom data were pooled to obtain a relative risk of remaining symptomatic after therapy as well as the number needed to treat with a 95% confidence interval.

RESULTS

We identified 17 RCTs involving 1,568 IBS patients that assessed elimination diets. Only three RCTs involving 230 patients met our eligibility criteria, all of which evaluated different approaches, and thus a meta-analysis could not be conducted.

CONCLUSIONS

More evidence is needed before generally recommending elimination diets for IBS patients.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

Irritable bowel syndrome: contemporary nutrition management strategies

Irritable bowel syndrome is a complex disorder whose pathophysiology involves alterations in the enteric microbiota, visceral hypersensitivity, gut immune/barrier function, hypothalamic-pituitary-adrenal axis regulation, neurotransmitters, stress response, psychological factors, and more. The importance of diet in the management of irritable bowel syndrome has taken center stage in recent times as the literature validates the relationship of certain foods with the provocation of symptoms. Likewise, a number of elimination dietary programs have been successful in alleviating irritable bowel syndrome symptoms. Knowledge of the dietary management strategies for irritable bowel syndrome will help guide nutritionists and healthcare practitioners to deliver optimal outcomes. This tutorial reviews the nutrition management strategies for irritable bowel syndrome.

A comparison between two different in vitro basophil activation tests for gluten- and cow's milk protein sensitivity in irritable bowel syndrome (IBS)-like patients

BACKGROUND

The diagnosis of food hypersensitivity (FH) in adult patients with gastrointestinal symptoms, beyond the immediate IgE-mediated clinical manifestations, is very often difficult. The aims of our study were to: 1) evaluate the frequency of FH in patients with irritable bowel syndrome (IBS)-like clinical presentation; and 2) compare the diagnostic accuracy of two different methods of in vitro basophil activation tests.

METHODS

Three hundred and five patients (235 females, age range 18-66 years) were included and underwent a diagnostic elimination diet and successive double-blind placebo-controlled (DBPC) challenges. Two different methods of in vitro basophil activation tests (BAT) (CD63 expression after in vitro wheat or cow's milk proteins stimulation) were evaluated: one was performed on separated leukocytes, and the other on whole blood.

RESULTS

Ninety patients of the 305 studied (29.5%) were positive to the challenges and were diagnosed as suffering from FH. BAT on separate leukocytes showed a sensitivity of 86% and a specificity of 91% in FH diagnosis. BAT on whole blood showed a sensitivity of 15%-20% and a specificity of 73% in FH diagnosis (p<0.0001 compared to the other method).

CONCLUSIONS

About one third of the IBS patients included in the study were suffering from FH and were cured on the elimination diet. The BAT based on CD63 detection on whole blood samples did not work in FH diagnosis and showed a significantly lower sensitivity, specificity and diagnostic accuracy than the assay based on separated leukocytes.

The relationship of food intolerance and irritable bowel syndrome in adults

The purpose of this literature review is to develop a thorough understanding of the research on food intolerance and its relationship to irritable bowel syndrome. Knowledge of the connection between the two conditions will assist allied healthcare professionals in working with patients to better manage their symptoms. Reduced healthcare costs may also result if patients are able to identify problematic foods and experience symptom improvement with diet changes. The review consists of an overview of food intolerance including prevalence, specific foods implicated including an in-depth review of research on bulk sweeteners, as well as methods of diagnosis. In addition, prevalence, specific foods associated with food intolerance in irritable bowel syndrome patients such as carbohydrates and lipids, nutritional consequences of food intolerance, and possible food-related methods of treatment including increased fiber intake are discussed. Finally, suggestions for future research and possible directions allied healthcare professionals can start with in assisting patients are provided.

Irritable bowel syndrome: Emerging paradigm in pathophysiology

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, characterized by abdominal pain, bloating, and changes in bowel habits. These symptoms cannot be explained by structural abnormalities and there is no specific laboratory test or biomarker for IBS. Therefore, IBS is classified as a functional disorder with diagnosis dependent on the history taking about manifested symptoms and careful physical examination. Although a great deal of research has been carried out in this area, the pathophysiology of IBS is complex and not completely understood. Multiple factors are thought to contribute to the symptoms in IBS patients; altered gastrointestinal motility, visceral hypersensitivity, and the brain-gut interaction are important classical concepts in IBS pathophysiology. New areas of research in this arena include inflammation, postinfectious low-grade inflammation, genetic and immunologic factors, an altered microbiota, dietary factors, and enteroendocrine cells. These emerging studies have not shown consistent results, provoking controversy in the IBS field. However, certain lines of evidence suggest that these mechanisms are important at least a subset of IBS patients, confirming that IBS symptoms cannot be explained by a single etiological mechanism. Therefore, it is important to keep in mind that IBS requires a more holistic approach to determining effective treatment and understanding the underlying mechanisms.

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.

Prevalence and predictors of irritable bowel syndrome among medical students and interns in King Abdulaziz University, Jeddah

BACKGROUND

Irritable bowel syndrome (IBS) is a frequent, costly, and potentially disabling gastrointestinal disorder. Medical education is among the most challenging and the most stressful education, and this may predispose to high rates of IBS.

OBJECTIVE

To determine the prevalence and predictors of IBS among medical students and interns in King Abdulaziz University, Jeddah, Saudi Arabia.

METHODS

A cross-sectional study was conducted among 597 medical students and interns selected by multistage stratified random sample method in 2012. A confidential, anonymous, and self-administered questionnaire was used to collect personal and sociodemographic data, level of emotional stress, and food hypersensitivity during the past 6 months. Rome III Criteria and the Standardized Hospital Anxiety and Depression Scale were also used.

RESULTS

The prevalence of IBS was 31.8%. Multiple logistic regression analysis revealed that the first predictor of IBS was female gender (aOR=2.89; 95.0% CI: 1.65-5.05). The second predictor was presence of morbid anxiety (aOR=2.44; 95.0% CI: 1.30-4.55). Living in a school dormitory, emotional stress during 6 months preceding the study, and the academic year were the next predictors.

CONCLUSIONS

High prevalence of IBS prevailed among medical students and interns. Female gender, morbid anxiety, living in school dormitory, emotional stress, and higher educational level (grade) were the predictors of IBS. Screening of medical students for IBS, psychological problems, and reducing stress by stress management are recommended.

Advances in understanding the relationship between inflammatory immune response and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a chronic functional bowel disease with abdominal pain, abdominal distension and bowel habit changes. Studies in recent years have demonstrated that intestinal mucosal inflammatory and immune activation plays an important role in the pathogenesis of IBS. In this paper we will review recent advances in understanding the relationship between intestinal mucosal inflammatory immune response and IBS.

Oligo-antigenic diet in the treatment of chronic anal fissures. Evidence for a relationship between food hypersensitivity and anal fissures

OBJECTIVES

Patients with chronic constipation due to food hypersensitivity (FH) had an elevated anal sphincter resting pressure. No studies have investigated a possible role of FH in anal fissures (AFs). We aimed to evaluate (1) the effectiveness of diet in curing AFs and to evaluate (2) the clinical effects of a double-blind placebo-controlled (DBPC) challenge, using cow's milk protein or wheat.

METHODS

One hundred and sixty-one patients with AFs were randomized to receive a "true-elimination diet" or a "sham-elimination diet" for 8 weeks; both groups also received topical nifedipine and lidocaine. Sixty patients who were cured with the "true-elimination diet" underwent DBPC challenge in which cow's milk and wheat were used.

RESULTS

At the end of the study, 69% of the "true-diet group" and 45% of the "sham-diet group" showed complete healing of AFs (P<0.0002). Thirteen of the 60 patients had AF recurrence during the 2-week cow's milk DBPC challenge and 7 patients had AF recurrence on wheat challenge. At the end of the challenge, anal sphincter resting pressure significantly increased in the patients who showed AF reappearance (P<0.0001), compared with the baseline values. The patients who reacted to the challenges had a significantly higher number of eosinophils in the lamina propria and intraepithelial lymphocytes than those who did not react to the challenges.

CONCLUSIONS

An oligo-antigenic diet combined with medical treatment improved the rate of chronic AF healing. In more than 20% of the patients receiving medical and dietary treatment, AFs recurred on DBPC food challenge.

Design of clinical trials evaluating dietary interventions in patients with functional gastrointestinal disorders

Clear guiding principles for the design and conduct of dietary intervention trials in functional gastrointestinal disorders (FGID) are lacking. This narrative review examines the specific challenges associated with the design and reporting in dietary intervention trials. Dietary intervention trials need to address the collinearity between food, nutrients, and bioactive components that obscure the relationship between food and their effects in the gut. Randomized, double-blinded, placebo-controlled studies remain the gold standard for dietary trials, but are limited by difficulties in adequate masking of study food or inappropriate choice of placebo food/diets. Provision of study diets as the preferred delivery method can somewhat address these limitations, although allowing good adherence compared with education-based dietary interventions. Issues associated with participant expectancies and dietary behaviors can alter the true effectiveness of a diet. In addition, failure to adjust for or report baseline intake of nutrients of interest can reduce their magnitude of benefit. Bias in subjective reports and choice of measurement tools can preclude accurate assessment of food-intake data. In the design of elimination and rechallenge studies, sufficient time period and adequate exclusion of dietary triggers are essential to ensure symptoms are well-controlled before rechallenging. The route and frequency of challenging, design of test food, and/or placebo should match the aims of the rechallenge phase. Long-term efficacy data of such therapeutic diets has been poorly documented in most studies. Standardized guidelines that address many of the challenges outlined above are suggested to strengthen the quality of evidence for dietary therapies in FGID.

Tolerance to a new free amino acid-based formula in children with IgE or non-IgE-mediated cow's milk allergy: a randomized controlled clinical trial

Background

Amino acid-based formulas (Aaf) are increasingly used in children with cow’s milk allergy (CMA). To be labeled hypoallergenic these formulas must demonstrate in clinical studies that they don’t provoke reactions in 90% of subjects with confirmed CMA with 95% confidence when given in prospective randomized, double-blind, placebo-controlled challenge (DBPCFC) trials. The majority of available safety data on Aaf derived from patients with IgE-mediated CMA. Considering substantial differences in the immunologic mechanism and clinical presentation of non-IgE-mediated CMA it’s important to investigate the hypoallergenicity of these formulas also in these patients. We prospectively assessed the tolerance to a new commercially available Aaf in children affected by IgE- or non-IgE-mediated CMA.

Methods

Consecutive patients affected by IgE- or non-IgE-mediated CMA, aged ≤ 4 years, were enrolled. DBPCFC was carried out with increasing doses of the new Aaf (Sineall, Humana, Milan, Italy), using validated Aaf as placebo. Faecal concentrations of calprotectin (FC) and eosinophilic cationic protein (ECP) were monitored.

Results

Sixty patients (44 male, 73.3%, median age 37, 95%CI 34.5–39.6 months, IgE-mediated CMA 29, 48.3%) were enrolled. At the diagnosis clinical symptoms were gastrointestinal (46.6%), cutaneous (36.6%), respiratory (23.3%), and systemic (10.0%). After DBPCFC with the new Aaf, no patient presented early or delayed clinical reactions. Faecal concentration of calprotectin and of ECP remained stable after the exposure to the new Aaf.

Conclusions

The new Aaf is well tolerated in children with IgE- or non-IgE-mediated CMA, and it could be used as a safe dietotherapy regimen for children with this condition.

Trial registration

The trial was registered in the ClinicalTrials.gov Protocol Registration System (ID number: NCT01622426).

Diet-microbiota interactions and their implications for healthy living

It is well established that diet influences the health of an individual and that a diet rich in plant-based foods has many advantages in relation to the health and well-being of an individual. What has been unclear until recently is the large contribution of the gut microbiota to this effect. As well as providing basic nutritional requirements, the long-term diet of an animal modifies its gut microbiota. In adults, diets that have a high proportion of fruit and vegetables and a low consumption of meat are associated with a highly diverse microbiota and are defined by a greater abundance of Prevotella compared to Bacteroides, while the reverse is associated with a diet that contains a low proportion of plant-based foods. Furthermore, it is becoming increasingly clear that the effect of the microbial ecology of the gut goes beyond the local gut immune system and is implicated in immune-related disorders, such as IBS, diabetes and inflamm-ageing. In this review, we investigate the evidence that a balanced diet leads to a balanced, diverse microbiota with significant consequences for healthy ageing by focusing on conditions of interest.

Association of HLA-DQ gene with bowel transit, barrier function, and inflammation in irritable bowel syndrome with diarrhea

Patients with irritable bowel syndrome (IBS) with diarrhea (IBS-D) carrying human leukocyte antigen (HLA)-DQ2/8 genotypes benefit from gluten withdrawal. Our objective was to compare gastrointestinal barrier function, mucosal inflammation, and transit in nonceliac IBS-D patients and assess association with HLA-DQ2/8 status. In 45 IBS-D patients who were naive to prior exclusion of dietary gluten, we measured small bowel (SB) and colonic mucosal permeability by cumulative urinary lactulose and mannitol excretion (0-2 h for SB and 8-24 h for colon), inflammation on duodenal and rectosigmoid mucosal biopsies (obtained in 28 of 45 patients), tight junction (TJ) protein mRNA and protein expression in SB and rectosigmoid mucosa, and gastrointestinal and colonic transit by validated scintigraphy. SB mucosal biopsies were stained with hematoxylin-eosin to assess villi and intraepithelial lymphocytes, and immunohistochemistry was used to assess CD3, CD8, tryptase, and zonula occludens 1 (ZO-1); colonic biopsy intraepithelial lymphocytes were quantitated. Associations of HLA-DQ were assessed using Wilcoxon's rank-sum test. Relative to healthy control data, we observed a significant increase in SB permeability (P < 0.001), a borderline increase in colonic permeability (P = 0.10), and a decrease in TJ mRNA expression in rectosigmoid mucosa in IBS-D. In HLA-DQ2/8-positive patients, ZO-1 protein expression in the rectosigmoid mucosa was reduced compared with that in HLA-DQ2/8-negative patients and colonic transit was slower than in HLA-DQ2/8-negative patients. No other associations with HLA genotype were identified. There is abnormal barrier function (increased SB permeability and reduced mRNA expression of TJ proteins) in IBS-D relative to health that may be, in part, related to immunogenotype, given reduced ZO-1 protein expression in rectosigmoid mucosa in HLA-DQ2/8-positive relative to HLA-DQ2/8-negative patients.

The microbiota link to irritable bowel syndrome: an emerging story

Irritable Bowel Syndrome (IBS) is a clinically heterogeneous disorder which is likely to involve a number of causative factors. The contribution of altered intestinal microbiota composition or function to this disorder is controversial, and is the subject of much current research. Until recently, the technical limitations of the methodologies available have not permitted an adequate survey of low-abundance microbial species. Recent technological developments have enabled the analysis of the global population of the microbiome using high through-put, culture independent, 16S rRNA amplicon pyrosequencing. Using these new methodologies, we are able to gain important biological insights into the link between functional bowel disorders and the microbiome. This addendum contextualizes and summarizes the results of these studies, and defines the future challenges and opportunities in the field.

Irritable bowel syndrome: methods, mechanisms, and pathophysiology. The confluence of increased permeability, inflammation, and pain in irritable bowel syndrome

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal ailments among those seeking health care for gastrointestinal disorders. Despite its prevalence, IBS pathophysiology is still not completely understood. Continued elucidation of IBS etiological mechanisms will lead to a greater appreciation of possible therapeutic targets. In the past decade, there has been increasing focus on the possible connection between increased intestinal mucosal permeability, inflammation, and visceral hypersensitivity. Increased permeability in subsets of IBS patients has been observed and the possible mechanisms underlying this defect are just beginning to be understood. The objectives of this review are to summarize the role of the healthy intestinal epithelium as a barrier between the lumen and the rest of the body with a focus on tight junctions; to examine the lines of evidence that suggest that different triggers lead to increased intestinal mucosal permeability and disruption of tight junctions in IBS patients; and to explore how this increased permeability may elicit immune responses that affect afferent nerves, resulting in the pain associated with IBS.