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CD4+ T-helper 22 (Th22) cells are a phenotypically distinct lymphocyte subset that produces high levels of interleukin (IL)-22 without co-production of IL-17A. However, the developmental origin and lineage classification of Th22 cells, their interrelationship to Th17 cells, and potential for plasticity at sites of infection and inflammation remain largely undefined. An improved understanding of the mechanisms underpinning the outgrowth of Th22 cells will provide insights into their regulation during homeostasis, infection, and disease. To address this knowledge gap we generated 'IL-17A-fate-mapping IL-17A/IL-22 reporter transgenic mice' and show that Th22 cells develop in the gastrointestinal tract and lung during bacterial infection without transitioning via an Il17a-expressing intermediate, although in some compartments alternative transition pathways exist. Th22-cell development was not dependent on T-bet; however, this transcription factor functioned as a promiscuous T-cell-intrinsic regulator of IL-17A and IL-22 production, in addition to regulating the outgrowth, phenotypic stability, and plasticity of Th22 cells. Thus, we demonstrate that at sites of mucosal bacterial infection Th22 cells develop as a distinct lineage independently of Th17 cells; though both lineages exhibit bidirectional phenotypic flexibility within infected tissues and their draining lymph nodes, and that T-bet plays a critical regulatory role in Th22-cell function and identity.

The prevalence of chronic immune and metabolic disorders is increasing rapidly. In particular, inflammatory bowel diseases, obesity, diabetes, asthma and chronic obstructive pulmonary disease have become major healthcare and economic burdens worldwide. Recent advances in microbiome research have led to significant discoveries of associative links between alterations in the microbiome and health, as well as these chronic supposedly noncommunicable, immune/metabolic disorders. Importantly, the interplay between diet, microbiome and the mucous barrier in these diseases has gained significant attention. Diet modulates the mucous barrier via alterations in gut microbiota, resulting in either disease onset/exacerbation due to a "poor" diet or protection against disease with a "healthy" diet. In addition, many mucosa-associated disorders possess a specific gut microbiome fingerprint associated with the composition of the mucous barrier, which is further influenced by host-microbiome and inter-microbial interactions, dietary choices, microbe immigration and antimicrobials. Our review focuses on the interactions of diet (macronutrients and micronutrients), gut microbiota and mucous barriers (gastrointestinal and respiratory tract) and their importance in the onset and/or progression of major immune/metabolic disorders. We also highlight the key mechanisms that could be targeted therapeutically to prevent and/or treat these disorders.

Background Inflammation results in significant shifts in tissue metabolism. Recent studies indicate that inflammation and hypoxia occur concomitantly. We examined whether circulating and tissue markers of hypoxia could serve as surrogate indicators of disease severity in adult and pediatric patients with inflammatory bowel disease (IBD). Methods Serum and colonic biopsies were obtained from pediatric subjects with active IBD colitis and adult subjects with active and inactive ulcerative colitis, along with healthy non-colitis controls of all ages. Disease activity was evaluated by endoscopy and histopathology. Levels of serum hypoxia markers (macrophage inflammatory protein-3α [MIP-3α], vascular endothelial growth factor [VEGF], and erythropoietin [EPO]) were measured. Results Children with active IBD colitis had higher levels of serum MIP-3α and VEGF compared to non-colitis controls (p

In this study, the intestinal permeability of metal(loid)s (MLs) such as arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) was examined, as influenced by gut microbes and chelating agents using an in vitro gastrointestinal/Caco-2 cell intestinal epithelium model. The results showed that in the presence of gut microbes or chelating agents, there was a significant decrease in the permeability of MLs (As-7.5%, Cd-6.3%, Pb-7.9% and Hg-8.2%) as measured by apparent permeability coefficient value (Papp), with differences in ML retention and complexation amongst the chelants and the gut microbes. The decrease in ML permeability varied amongst the MLs. Chelating agents reduce intestinal absorption of MLs by forming complexes thereby making them less permeable. In the case of gut bacteria, the decrease in the intestinal permeability of MLs may be associated to a direct protection of the intestinal barrier against the MLs or indirect intestinal ML sequestration by the gut bacteria through adsorption on bacterial surface. Thus, both gut microbes and chelating agents can be used to decrease the intestinal permeability of MLs, thereby mitigating their toxicity.

We read with interest the recent work by Stevens et al 1 showing the association between zonulin, fatty acid binding protein 2 (FABP2) and lipopolysaccharide (LPS) plasma levels and increased gut permeability in asymptomatic gastroenterology patients with depression and anxiety disorders, when compared with controls. Zonulin is a regulator of intestinal permeability and a marker of intestinal barrier impairment,2 which is reported in the irritable bowel syndrome (IBS) and functional dyspepsia (FD),3 both of which are associated with anxiety and depression.4 5 The tight junctional protein zonulin (ZO-1) is significantly reduced in these patients possibly driving a low-grade immune response.3 6 The utility of serum zonulin as a biomarker is controversial. One study observed higher serum zonulin levels in coeliac disease (CD) (mean 0.033 ng/mg total proteins), non-coeliac gluten sensitivity (NCGS) (mean 0.030 ng/mg total proteins) and IBS-diarrhoea (mean 0.012 ng/mg total proteins) patients, versus healthy controls,7 but the Malmo Diet and Cancer cardiovascular cohort showed no association between serum zonulin and reported GI symptoms or IBS and FD.8 We aimed to examine serum zonulin as a biomarker for IBS and FD. Adult participants were recruited from two sources9; (1) a population-based study (n=242; mean age 62.1 (SD=11.9) years; 45.9% female) and (2) a two-site hospital-based study (n=102; mean age 45.0 (SD=16.2) years; 67.4% female). In the population-based study, IBS (n=40) and FD (n=42) were diagnosed according to modified Rome III criteria, while CD (n=6), gluten intolerance (n=6) and NCGS (n=44) had self-reported doctor diagnoses. Healthy controls (n=182) did not meet Rome …

Subtle histopathologic features such as eosinophilia and increased mast cells have been observed in functional gastrointestinal disorders (FGIDs), including functional dyspepsia (FD) and the irritable bowel syndrome (IBS). The mechanisms that drive recruitment of these cells to the gastrointestinal tract remain unexplained, largely due to the heterogeneity in phenotypes among patients diagnosed with such conditions. We aimed to systematically review the literature and collate the evidence for immune activation in FD and IBS, and where possible, detail the nature of activation.Seven literature databases were searched using the keywords: 'functional gastrointestinal disorder', FGID, 'functional dyspepsia', 'non-ulcer dyspepsia', 'idiopathic dyspepsia', 'irritable bowel syndrome', IBS and 'immun*'.Fifty-one papers reporting discordant immune features met the selection criteria for this review. Changes in lymphocyte populations, including B and T lymphocyte numbers and activation status were reported in IBS and FD, in conjunction with duodenal eosinophilia in FD and increased colonic mast cells in IBS. Increases in circulating α4+β7+ gut-homing T cells appear to be linked to the pathophysiology of both FD and IBS. Studies in the area are complicated by poor phenotyping of patients into subgroups and the subtle nature of the immune activity involved in FD and IBS.Alterations in proportions of gut-homing T lymphocytes in both FD and IBS indicate that a loss of mucosal homeostasis may drive the symptoms of FD and IBS. There is indirect evidence that Th17 responses may play a role in FGIDs, however the evidence for a Th2 immune phenotype in FD and IBS is limited. Although immune involvement is evident, large, well-characterised patient cohorts are required to elucidate the immune mechanisms driving the development of FGIDs.

Functional dyspepsia (FD) is a common disorder of gut-brain interaction, characterised by upper gastrointestinal symptom profiles that differentiate FD from the irritable bowel syndrome (IBS), although the two conditions often co-exist. Despite food and eating being implicated in FD symptom induction, evidence-based guidance for dietetic management of FD is limited. The aim of this narrative review is to collate the possible mechanisms for eating-induced and food-related symptoms of FD for stratification of dietetic management. Specific carbohydrates, proteins and fats, or foods high in these macronutrients have all been reported as influencing FD symptom induction, with removal of ‘trigger’ foods or nutrients shown to alleviate symptoms. Food additives and natural food chemicals have also been implicated, but there is a lack of convincing evidence. Emerging evidence suggests the gastrointestinal microbiota is the primary interface between food and symptom induction in FD, and is therefore a research direction that warrants substantial attention. Objective markers of FD, along with more sensitive and specific dietary assessment tools will contribute to progressing towards evidence-based dietetic management of FD.

Globally, more than one-third of adults are overweight. Overweight and obesity are complex and multifaceted conditions, associated with an increased risk of chronic illness and early mortality. While there are known risk factors, these alone do not fully explain the varying outcomes between individuals. Recently, taste receptors have been proposed to have a role in the risk for obesity. These receptors are expressed throughout the gastrointestinal tract. In this system, they may be involved in modulating dietary intake and metabolic processes. The taste 2 family of receptors (T2Rs) detects bitter compounds. Receptors T2R4 and T2R5 detect (-)-epicatechin (epicatechin), an antioxidant polyphenol, which may have protective effects against obesity. However, the potential role for taste receptors in this association has not been explored. This study assessed whether polymorphisms in TAS2R4 (rs2233998 and rs2234001) and TAS2R5 (rs2227264) were associated with body mass index (BMI). Genotyping (Taqman qPCR assays) was performed on DNA extracted from blood samples (n = 563) from an elderly cohort. Homozygosity for the minor allele of all polymorphisms was significantly associated with a lower BMI in males. The TAS2R4-rs2233998 CC genotype, the TAS2R4-rs2234001 CC genotype and the TAS2R5-rs2227264 TT genotype were associated with lower BMI (2.1, 2.1 and 2.2 units, p = 0.002, 0.003 and 0.001, respectively). Epicatechin intake was not associated with BMI and genotype was not associated with epicatechin intake. This suggests that the association between TAS2R genotype and elevated BMI risk occurs through altered extra-oral responses and not directly via altered epicatechin intake.

Background & Aims: Excessive shedding of apoptotic enterocytes into the intestinal lumen is observed in inflammatory bowel disease and is correlated with disease relapse. Based on their cytolytic capacity and surveillance behavior, we investigated whether intraepithelial lymphocytes expressing the γδ T cell receptor (γδ IELs) are actively involved in the shedding of enterocytes into the lumen. Methods: Intravital microscopy was performed on GFP γδ T cell reporter mice treated with intraperitoneal lipopolysaccharide (10 mg/kg) for 90 minutes to induce tumor necrosis factor–mediated apoptosis. Cell shedding in various knockout or transgenic mice in the presence or absence of blocking antibody was quantified by immunostaining for ZO-1 funnels and cleaved caspase-3 (CC3). Granzyme A and granzyme B release from ex vivo–stimulated γδ IELs was quantified by enzyme-linked immunosorbent assay. Immunostaining for γδ T cell receptor and CC3 was performed on duodenal and ileal biopsies from controls and patients with Crohn's disease. Results: Intravital microscopy of lipopolysaccharide-treated mice revealed that γδ IELs make extended contact with shedding enterocytes. These prolonged interactions require CD103 engagement by E-cadherin, and CD103 knockout or blockade significantly reduced lipopolysaccharide-induced shedding. Furthermore, we found that granzymes A and B, but not perforin, are required for cell shedding. These extracellular granzymes are released by γδ IELs both constitutively and after CD103/E-cadherin ligation. Moreover, we found that the frequency of γδ IEL localization to CC3-positive enterocytes is increased in Crohn's disease biopsies compared with healthy controls. Conclusions: Our results uncover a previously unrecognized role for γδ IELs in facilitating tumor necrosis factor–mediated shedding of apoptotic enterocytes via CD103-mediated extracellular granzyme release.

Intense sweeteners (IS) are often marketed as a healthier alternative to sugars, with the potential to aid in combating the worldwide rise of diabetes and obesity. However, their use has been counterintuitively associated with impaired glucose homeostasis, weight gain and altered gut microbiota. The nature of these associations, and the mechanisms responsible, are yet to be fully elucidated. Differences in their interaction with taste receptors may be a potential explanatory factor. Like sugars, IS stimulate sweet taste receptors, but due to their diverse structures, some are also able to stimulate bitter taste receptors. These receptors are expressed in the oral cavity and extra-orally, including throughout the gastrointestinal tract. They are involved in the modulation of appetite, glucose homeostasis and gut motility. Therefore, taste genotypes resulting in functional receptor changes and altered receptor expression levels may be associated with metabolic conditions. IS and taste receptors may both interact with the gastrointestinal microbiome, and their interactions may potentially explain the relationship between IS use, obesity and metabolic outcomes. While these elements are often studied in isolation, the potential interactions remain unexplored. Here, the current evidence of the relationship between IS use, obesity and metabolic outcomes is presented, and the potential roles for interactions with taste receptors and the gastrointestinal microbiota in modulating these relationships are explored.

Introduction: Functional dyspepsia (FD) is one of the most common functional gastrointestinal disorders and is classified into postprandial distress and epigastric pain syndrome. Despite the recognition of duodenal inflammation as a potential trigger of symptoms, only limited anti-inflammatory therapies exist.Areas covered: This narrative review summarizes the recent advances in the pathophysiology and treatment of FD; it identifies potential therapeutic targets and gaps in the field. An electronic literature search was conducted in Pubmed up to 31st of December 2019.Expert opinion: There is compelling evidence for the role of duodenal inflammation and the eosinophil-mast cell axis in the pathogenesis of dyspeptic symptoms. Traditional prokinetic drugs and neuromodulators target gastric dysmotility and visceral hypersensitivity but are hampered by limited efficacy and side effects. Independent of acid suppression, the anti-inflammatory action of proton pump inhibitors, which remain the first-line therapy in FD, may also explain their therapeutic effect. Other existing and newly established anti-inflammatory drugs should be investigated while trials including probiotics and selective antibiotics should examine the host microbiome and immune activation. Targeted treatments for potential causes of duodenal pathology, such as impaired permeability and dysbiosis, are likely to emerge in the future.

Background and aim: Managing patients with a chronic condition such as inflammatory bowel disease (IBD), requires a multidiscipline approach. The pharmacist might be the first point of contact for patients with initial symptoms or relapsing flares, yet there is no available literature on the role of pharmacists in IBD management. We conducted a survey to explore pharmacists&rsquo, confidence in and potential barriers to managing IBD and assess the impact of IBD education on their confidence in IBD management. Methods: Surveys assessing confidence levels in managing IBD, additional learning opportunities about IBD and barriers to their learning of IBD management were provided to pharmacists for completion before and after attending an IBD-specific education session at a national conference. Results: Of the 195 attendees, 125 participants completed the survey (64%). Most respondents reported a low to mid-range level of confidence with managing IBD. Specifically, they were only slightly confident in decision making on patient care, addressing patient needs and providing additional support for IBD patients, and somewhat confident with understanding, management and providing relevant information on IBD. Whist the education session improved pharmacists perceived level of confidence, most respondents indicated a need to learn more about IBD. Areas of additional learning included science, drug therapy, treatments (includes non-pharmacological options as well) and guidelines. A majority of pharmacists identified time constraints as a key barrier to learning. Conclusion: Pharmacists lack sufficient confidence about managing inflammatory bowel disease. These data indicate support within the pharmacy profession to play a more active role in the management of IBD.

Background: Small intestinal bacterial overgrowth may play a role in gastrointestinal and non-gastrointestinal diseases. Aims: To use quantitative polymerase chain reaction (qPCR) to determine and compare bacterial loads of duodenal biopsies in asymptomatic controls, and patients with functional gastrointestinal disorders (FGIDs) and inflammatory bowel disease (IBD) including ulcerative colitis (UC) and Crohn’s disease (CD). To define effects of gastric acid inhibition on bacterial load, explore links of bacterial load and gastrointestinal symptoms in response to a standardised nutrient challenge and compare bacterial load with glucose breath test results. Methods: In 237 patients (63 controls, 84 FGID and 90 IBD), we collected mucosal samples under aseptic conditions during endoscopy extracted and total DNA. Bacterial load metric was calculated utilising qPCR measurements of the bacterial 16S rRNA gene, normalised to human beta-actin expression. Standard glucose breath test and nutrient challenge test were performed. Results: The duodenal microbial load was higher in patients with FGID (0.22 ± 0.03) than controls (0.07 ± 0.05; P = 0.007) and patients with UC (0.01 ± 0.05) or CD (0.02 ± 0.09), (P = 0.0001). While patients treated with proton pump inhibitors (PPI) had significantly higher bacterial loads than non-users (P < 0.05), this did not explain differences between patient groups and controls. Bacterial load was significantly (r = 0.21, P < 0.016) associated with the symptom response to standardised nutrient challenge test. Methane, but not hydrogen values on glucose breath test were associated with bacterial load measured utilising qPCR. Conclusions: Utilising qPCR, a diagnosis of FGID and treatment with PPI were independently associated with increased bacterial loads. Increased bacterial loads are associated with an augmented symptom response to a standardised nutrient challenge.

Incidence rates of inflammatory bowel disease (IBD) are increasing worldwide. This correlates with increased consumption of red meats, alcohol, refined sugars, oils and animal fats, typical of a “Western” diet. Poor dietary habits are the most ubiquitous environmental factor implicated in IBD, along with gastrointestinal dysbiosis. Taste genetics and oral receptor expression levels determine dietary preferences and therefore, nutritional intake. Taste receptors (TRs) are also expressed throughout the gastrointestinal tract, where they are involved in modulating metabolic processes and gastrointestinal function. Importantly, these receptors are known to be involved in the modulation of inflammatory processes in the respiratory tract. In this system, TRs detect and respond to bacteria and bacterial signalling molecules and initiate protective responses. We propose that TRs play a similar role in the gastrointestinal tract, thereby modulating risk for IBD. TRs may indirectly affect risk for IBD by altering dietary intake, and therefore microbial composition and function. Alternatively, TRs may directly detect and respond to gastrointestinal bacterial components. Overall, there is evidence to suggest an emerging role for TRs in the aetiology of IBD. Furthermore, targeting these receptors via dietary modulation may have therapeutic potential. Keywords: Taste receptors, Nutrition, Microbiome, Inflammatory bowel disease, Diet

© 2018 Wolters Kluwer Health, Inc. All rights reserved. BACKGROUND Cell-free mitochondrial DNA (mtDNA) is proinflammatory and has been detected in high concentrations in trauma patients' plasma. Deoxyribonuclease (DNAse) is the free plasma enzyme responsible for the digestion of extracellular DNA. The relationship between mtDNA and DNAse after major trauma is unknown. We hypothesized that DNAse activity would be elevated after injury and trauma surgery and would be associated with high concentrations of extracellular DNA. METHODS Two-year prospective study was performed on 103 consecutive trauma patients (male, 81%; age, 38 years [interquartile range, 30-59 years]; injury severity score, 18 [interquartile range, 12-26 years]) who underwent standardized major orthopedic trauma surgical interventions. Blood was collected at five perioperative time points (preoperative, postoperative, 7 hours, 24 hours, and 3 days postoperatively). Healthy control subjects (n = 20) were also sampled. Cell-free mtDNA and nuclear DNA (nDNA) were measured using quantitative polymerase chain reaction. Deoxyribonuclease was also assayed in the same plasma samples. RESULTS Increased levels of mtDNA (from preoperative 163 ± 86 ng/mL to 3 days 282 ± 201 ng/mL, p < 0.0001) and nDNA (from preoperative 28 ± 20 ng/mL to 3 days 37 ± 27 ng/mL, p < 0.05) were present in trauma patients at all perioperative time points compared with healthy controls (mtDNA: 4 ± 2 ng/mL; nDNA: 10 ± 5 ng/mL). Deoxyribonuclease activity was lower in the trauma cohort (from preoperative 0.06 ± 0.04U/mL to 3 days 0.08 ± 0.04U/mL, p < 0.0001) compared with healthy controls (DNAse: 0.17 ± 0.03U/mL). There was no correlation between DNAse and perioperative DNA concentrations. Elevated mtDNA (but not nDNA) correlated with the development of systemic inflammatory response syndrome (SIRS) (p = 0.026) but not multiple organ failure. CONCLUSIONS The significant perioperative elevation in plasma-free mtDNA concentration is associated with the development of SIRS. The fact that increased cell-free DNA concentrations present with significantly lower than healthy control DNAse activity suggests a potential therapeutic opportunity with DNAse administration to modulate postinjury severe SIRS. LEVEL OF EVIDENCE Prognostic/Epidemiological, level II.

The global population has more than doubled over the past 40 years, supported by the ‘green revolution’ in agriculture producing high-yield grain varieties, including wheat, that are central to the modern diet.1 Wheat covers more than 200 million hectares of land,2 is the third most produced cereal behind rice and maize,3 and is responsible for one-fifth of the world’s calorific input.2 Wheat contains gluten proteins, predominantly made of equal parts of glutenins and gliadins, which are resistant to digestion, and their partially digested epitopes are immunogenic and central to the process that leads to coeliac disease,3 4 an autoimmune condition characterised by an aberrant immune response to ingested gluten in genetically susceptible individuals, which results in small bowel inflammation, enteropathy and potential malabsorption.5 The prevalence of coeliac disease in the past 50 years has risen to approximately 0.7%–2%, a phenomenon attributed to increased awareness and detection, as well as a true increase in prevalence.6 7 The sole and current only curative treatment, a lifelong gluten-free diet, considered central to the management of coeliac disease has also seen increasing popularity in the general population; there is a widespread underlying belief that a gluten-free diet may be ‘healthier’, despite a lack of evidence to support this notion and even evidence that it may be harmful to the non-coeliac population.8 This has seen the gluten-free food industry boom to an estimated US$6 billion per year industry.5 Gluten, or more generally wheat, has also been associated with other GI disease. In the absence of coeliac disease and under the guise of the increasingly fashionable but controversial label ‘non-coeliac gluten/wheat sensitivity’ (NCG/WS), gluten has been popularised in the press as a potential cause of almost all possible conceivable physiological complaints, ranging from GI to neurological, dermatological, psychological and musculoskeletal …

© 2018 American Society for Investigative Pathology Inflammatory bowel disease (IBD) is associated with several immune-mediated extraintestinal manifestations. More than half of all IBD patients have some form of respiratory pathology, most commonly neutrophil-mediated diseases, such as bronchiectasis and chronic bronchitis. Using murine models of colitis, we aimed to identify the immune mechanisms driving pulmonary manifestations of IBD. We found increased neutrophil numbers in lung tissue associated with the pulmonary vasculature in both trinitrobenzenesulfonic acid– and dextran sulfate sodium–induced models of colitis. Analysis of systemic inflammation identified that neutrophilia was associated with bacteremia and pyrexia in animal models of colitis. We further identified IL-6 as a systemic mediator of neutrophil recruitment from the bone marrow of dextran sulfate sodium animals. Functional inhibition of IL-6 led to reduced systemic and pulmonary neutrophilia, but it did not attenuate established colitis pathology. These data suggest that systemic bacteremia and pyrexia drive IL-6 secretion, which is a critical driver for pulmonary manifestation of IBD. Targeting IL-6 may reduce neutrophil-associated extraintestinal manifestations in IBD patients.

The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T84cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50–150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl−channels, whereas inhibition of CFTR activity with either CFTR-inh-172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50–150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment.NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes wound healing, suggesting it may provide an alternative approach to prevent the losses of barrier function that are associated with mucosal inflammation in IBD patients.

Objectives: Gastrointestinal (GI) inflammation and GI integrity deficits are common comorbidities of neuropsychiatric disorders. Ongoing research suggests that these aberrations may be contributing to heightened immune signals that have the potential to disrupt neuronal homeostasis and exacerbate behavioural deficits. The current study aimed to determine whether the well-characterized animal model of neuropsychopathology, the maternal immune activation (MIA) model, produced GI inflammation and integrity disruptions in association with anxiety-like behaviour. Methods: Pregnant Wistar rats were exposed to the viral mimetic polyriboinosinic:polyribocytidilic acid (polyI:C) on gestational days (GD) 10 and 19. Evidence of ANS activation, GI inflammation, and GI barrier integrity was assessed in both neonatal (postnatal day, P7) and adult (P84) offspring. Anxiety-like behaviour was assessed at P100. Results: Neonatal MIA offspring exhibited an altered intestinal inflammatory profile and evidence of an increase in lymphoid aggregates. MIA neonates also displayed disruptions to GI barrier tight junction protein mRNA. In addition, adult MIA offspring exhibited an increase in anxiety-like behaviours. Conclusion: These results indicate that the MIA rat model, which is well documented to produce behavioural, neurochemical, and neuroanatomical abnormalities, also produces GI inflammation and integrity disruptions. We suggest that this model may be a useful tool to elucidate biological pathways associated with neuropsychiatric disorders.

Visceral pain in inflammatory and functional gastrointestinal conditions is a major clinical problem. The exact mechanisms underlying the development of pain, during and after visceral inflammation are unknown. However, clinical and pre-clinical evidence suggests plasticity within the spinal cord dorsal horn is a contributing factor. Here we use an in vivo preparation and patch-clamp electrophysiology to test whether the synaptic and intrinsic properties of superficial dorsal horn (SDH) neurons are altered 5days after the induction of mild colitis in adult male mice (i.e. during acute inflammation of the colon). Whole-cell recordings were made from lumbosacral (L6-S1) superficial dorsal horn neurons (SDH), in animals under isoflurane anesthesia. Noxious colorectal distension (CRD) was used to identify SDH neurons with colonic inputs, while stimulation of the hind paw and tail was employed to assess convergent cutaneous input. Following inflammation, a significantly increased proportion of SDH neurons received both colonic and cutaneous inputs, compared to neurons in naïve animals. In addition, the nature and magnitude of responses to CRD and cutaneous stimulation differed in inflamed animals, as was spontaneous excitatory synaptic drive. Conversely, several measures of intrinsic excitability were altered in a manner that would decrease SDH network excitability following colitis. We propose that during inflammation, sensitization of colonic afferents results in increased signaling to the SDH. This is accompanied by plasticity in SDH neurons whereby their intrinsic properties are changed to compensate for altered afferent activity.

Food ingestion is heavily implicated in inducing symptoms of irritable bowel syndrome (IBS) and functional dyspepsia (FD), which affect over one-third of adults in developed countries. The primary aim of this paper was to assess the alignment of dietary assessment and symptom-reporting capture periods in diet-related studies on IBS or FD in adults. Secondary aims were to compare the degree of alignment, validity of symptom-reporting tools and reported significant associations between food ingestion and symptoms. A five-database systematic literature search resulted in 40 included studies, from which data were extracted and collated. The food/diet and symptom capture periods matched exactly in 60% (n = 24/40) of studies, overlapped in 30% (n = 12/40) of studies and were not aligned in 10% (n = 4/40) of studies. Only 30% (n = 12/40) of studies that reported a significant association between food and global gastrointestinal symptoms used a validated symptom-reporting tool. Of the thirty (75%) studies that reported at least one significant association between individual gastrointestinal symptoms and dietary intake, only four (13%) used a validated symptom tool. Guidelines to ensure that validated symptom-reporting tools are matched with fit-for-purpose dietary assessment methods are needed to minimise discrepancies in the alignment of food and symptom tools, in order to progress functional gastrointestinal disorder research.

Background Anastomotic leak rates have not improved over several decades despite improvements in surgical techniques and patient care. The gut microbiome has been implicated in the development of leaks. The exact mechanisms by which tissue oxygenation affects gut microbial composition and anastomotic healing physiology are unclear. Also, commonly used carbon dioxide (CO2) is a known vasodilator that improves tissue oxygen tension. We performed a systematic review to determine the influence of hyperoxia, hypoxia, and hypercapnia on the gut microbiome and anastomotic healing. Methods A literature search was performed in MEDLINE, EMBASE, and COCHRANE to identify studies investigating the effects of hyperoxia, hypoxia, and hypercapnia on anastomotic healing and gut microbiota published between 1998 and 2018. Two reviewers screened the articles for eligibility and quality. Fifty-three articles underwent full text review, and a narrative synthesis was undertaken. Results Hyperoxia is associated with better anastomotic healing, increased gastrointestinal oxygen tension, and may reduce gut anaerobes. Hypoxia is associated with poor healing and increased gut anaerobes. However, it is unclear if hypoxia is the most important predictor of anastomotic leaks. Low pressure CO2 pneumoperitoneum and mild systemic hypercapnia are both associated with increased gastrointestinal oxygen tension and may improve anastomotic healing. We found no studies which investigated the effect of hypercapnia on gut microbiota in the context of anastomotic healing. Conclusions Tissue oxygenation influences gut anastomotic healing, but little evidence exists to demonstrate the influence on the gut microbiome in the context of healing. Further studies are needed to determine if anastomotic microbiome changes with altered tissue oxygenation and if this affects healing and leak rates. If confirmed, altering tissue oxygenation through hyperoxia or hypercapnia could be feasible means of altering the microbiome such that anastomotic leak rates reduce.

The authors conducted a systematic review and meta-analysis to assess the effect of antibiotic therapy in primary sclerosing cholangitis (PSC). Effect of antibiotic therapy on Mayo PSC Risk Score (MRS), serum alkaline phosphatase (ALP), total serum bilirubin (TSB), and adverse events (AEs) rates were calculated and expressed as standardized difference of means or proportions. Five studies including 124 PSC patients who received antibiotics were included. Overall, antibiotic treatment was associated with a statistically significant reduction in ALP, MRS, and TSB by 33.2, 36.1, and 28.8%, respectively. ALP reduction was greatest for vancomycin (65.6%, p

Liver inflammation is a common extraintestinal manifestation in inflammatory bowel disease (IBD), yet, the mechanisms driving gut-liver axis inflammation remain poorly understood. IBD leads to a breakdown in the integrity of the intestinal barrier causing an increase in portal and systemic gut-derived antigens, which challenge the liver. Here, we examined the role of platelet activating factor receptor (PAFR) in colitis-associated liver damage using dextran sulfate sodium (DSS) and anti-CD40-induced colitis models. Both DSS and anti-CD40 models exhibited liver inflammation associated with colitis. Colitis reduced global PAFR protein expression in mouse livers causing an exclusive re-localization of PAFR to the portal triad. The global decrease in liver PAFR was associated with increased sirtuin 1 while relocalized PAFR expression was limited to Kupffer cells (KCs) and co-localized with toll-like receptor 4. DSS activated the NLRP3-inflammasome and increased interleukin (IL)-1β in the liver. Antagonism of PAFR amplified the inflammasome response by increasing NLRP3, caspase-1, and IL-1β protein levels in the liver. LPS also increased NLRP3 response in human hepatocytes, however, overexpression of PAFR restored the levels of NLPR3 and caspase-1 proteins. Interestingly, KCs depletion also increased IL-1β protein in mouse liver after DSS challenge. These data suggest a protective role for PAFR-expressing KCs during colitis and that regulation of PAFR is important for gut-liver axis homeostasis.

Primary atopic disorders can be classified as heritable genetic disorders presenting with deregulated pathogenic allergic effector responses irrespective of sensitization. In the last decade, there are parallel rises in the burden of atopic and gastrointestinal (GI) diseases. Areas covered: There is increasing recognition of an association between atopy and GI disease through immune dysregulation, the microbiome and shared genetic pathways. Since the first article on atopy and the GI tract in 2014 in this journal, many more studies have shed light on the shared pathways in these diseases, particularly in the field of eosinophilic GI disease, functional GI disorders, and inflammatory bowel disease. Expert opinion: Understanding the links with common mechanisms in atopy and GI diseases that may lead to better targeting of treatment through manipulation of immune mechanisms, the microbiome, genetics, food allergens and specific GI diseases such as inflammatory bowel disease, functional GI disorders.

Asthma is a common, heterogeneous and serious disease with high prevalence globally. Poorly controlled, steroid-resistant asthma is particularly important as there are no effective therapies and it exerts substantial healthcare and societal burden. The role of microbiomes, particularly in chronic diseases has generated considerable interest in recent times. Existing evidence clearly demonstrates an association between asthma initiation and the microbiome, both respiratory and gastro-intestinal, although its' roles are poorly understood when assessing the asthma progression or heterogeneity (i.e. phenotypes/endotypes) across different geographical locations. Moreover, modulating microbiomes could be preventive and/or therapeutic in patients with asthma warrants urgent attention. Here, we review recent advances in assessing the role of microbiomes in asthma and present the challenges associated with the potential therapeutic utility of modifying microbiomes in management.

Objectives: To determine the incidence of self-reported non-coeliac wheat sensitivity (SR-NCWS) and factors associated with its onset and resolution; to describe the prevalence of factors associated with gluten avoidance. Design: Longitudinal cohort study; analysis of responses to self-administered validated questionnaires (Digestive Health and Wellbeing surveys, 2015 and 2018). Setting, participants: Subset of an adult population sample randomly selected in 2015 from the electoral rolls for the Newcastle and Gosford regions of New South Wales. Main outcome measures: Prevalence of SR-NCWS (2015, 2018) and incidence and resolution of SR-NCWS, each by demographic and medical factors; prevalence of gluten avoidance and reasons for gluten avoidance (2018). Results: 1322 of 2185 eligible participants completed the 2018 survey (response rate, 60.5%). The prevalence of SR-NCWS was similar in 2015 (13.8%; 95% CI, 12.0–15.8%) and 2018 (13.9%; 95% CI, 12.1–15.9%); 69 of 1301 respondents (5.3%) reported developing new onset (incident) SR-NCWS between 2015 and 2018 (incidence, 1.8% per year). Incident SR-NCWS was significantly associated with a diagnosis of functional dyspepsia, and negatively associated with being male or older. Gluten avoidance was reported in 2018 by 24.2% of respondents (20.5% partial, 3.8% complete avoidance); general health was the most frequent reason for avoidance (168 of 316 avoiders, 53%). All 13 participants with coeliac disease, 56 of 138 with irritable bowel syndrome (41%), and 69 of 237 with functional dyspepsia (29%) avoided dietary gluten. Conclusions: The prevalence of SR-NCWS was similar in 2015 and 2018. Baseline (2015) and incident SR-NCWS (2018) were each associated with functional gastrointestinal disorders. The number of people avoiding dietary gluten exceeds that of people with coeliac disease or SR-NCWS, and general health considerations and abdominal symptoms are the most frequently reported reasons for avoidance.

The gastrointestinal epithelium is a highly regenerative organ, where each cell is replaced in a cycle of 4-6 days, depending on the mammalian species. This highly proliferative state is driven by gastrointestinal stem and progenitor cells, located at the base of crypts. These cells give rise to at least six types of differentiated epithelial cells, each with a distinct function in maintaining homeostasis between the intestinal interface and the luminal environment. The isolation and culture of these cells from mammalian gastrointestinal tissue is a novel technique, which allows for the generation and maintenance of an in vitro culture system for adult epithelial cells. There are two predominant methods for isolation and propagation of gastrointestinal epithelial cells, the first is the organoid system developed in 2009, and the second is a later version known as the L-WRN spheroid system. In this chapter, we describe the method to isolate and culture human gastrointestinal stem and progenitor cells and culture them as three-dimensional spheroids using L-WRN cell conditioned media.

Background and aims: Chronic disease, particularly inflammatory bowel disease (IBD), requires a multifaceted approach to managing patients, but it is apparent that primary care pharmacists are being underutilized. To demonstrate the benefits of pharmacist interventions in primary care, a systematic review was conducted of interventions in asthma and type 2 diabetes where pharmacists have a defined role in chronic disease management. We also explored potential opportunities for primary care pharmacists to deliver tailored care to patients with inflammatory bowel disease. Methods: The search strategy retrieved original research articles from seven databases; eligible articles were assessed for inclusion. Quality appraisal was performed independently by two reviewers. Results: Thirty-seven included studies were grouped into four categories of interventions: education/counseling (43%), medication management (34%), monitoring/follow-up (17%), and screening/risk prevention (6%). Education plus counseling was reported as the main intervention delivered by pharmacists. Three measurable outcomes were identified: clinical, humanistic (e.g., quality of life), and economic. Clinical outcomes (63%) were reported more commonly than humanistic (26%) and economic (11%) outcomes. Pharmacist interventions led to statistically significant improvements in control of disease, severity, and medication adherence, as well as improvements in overall patient satisfaction, quality of life among patients with asthma and type 2 diabetes. Conclusion: As one of the most accessible sources of primary health care, pharmacists are well-placed to minimize the impact of chronic diseases on patients and communities. Evidence suggests there are opportunities for primary care pharmacists to play a more active role in the management of chronic diseases such as IBD.

Genetics, Mucosal Inflammation, and the Environment in Post-Infectious Chronic Gut Syndromes

Chronic abdominal pain is a common symptom of inflammatory bowel disease and often persists in the absence of gut inflammation. Although the mechanisms responsible for ongoing pain are unknown, clinical and preclinical evidence suggests lumbosacral spinal cord dorsal horn neurons contribute to these symptoms. At present, we know little about the intrinsic and synaptic properties of this population of neurons in either normal or inflammed conditions. Therefore, we developed an in vivo preparation to make patch-clamp recordings from superficial dorsal horn (SDH) neurons receiving colonic inputs in naive male mice. Recordings were made in the lumbosacral spinal cord (L6-S1) under isoflurane anesthesia. Noxious colorectal distension (CRD) was used to determine whether SDH neurons received inputs from mechanical stimulation/distension of the colon. Responses to hind paw/tail cutaneous stimulation and intrinsic and synaptic properties were also assessed, as well as action potential discharge properties. Approximately 11% of lumbosacral SDH neurons in the cohort of neurons sampled responded to CRD and a majority of these responses were subthreshold. Most CRD-responsive neurons (80%) also responded to cutaneous stimuli, compared with

Crohn's disease (CD) is a chronic disease characterized by episodic and disabling inflammation of the gastrointestinal tract in genetically susceptible individuals. The incidence and prevalence of CD is rising rapidly across the world emphasising that disease risk is also influenced by environmental and lifestyle factors, as well as the microbial community resident in the gut. Childhood-onset CD is associated with an aggressive disease course that can adversely impact patient growth and development. There is no cure for CD however new onset and recurrent cases of paediatric CD are often responsive to exclusive enteral nutrition (EEN) treatment. EEN treatment involves the exclusive consumption of an elemental or polymeric formula for several weeks and it is well established as a primary intervention strategy. EEN treatments typically achieve remission rates of over 80% and importantly they are associated with a high rate of mucosal healing, far superior to steroids, which is prognostic of improved long-term health outcomes. Furthermore, they are safe, have few side effects, and improve nutritional status and linear growth. Surprisingly, despite the utility of EEN our understanding of the host-microbe-diet interactions that underpin clinical remission and mucosal healing are limited. Here, we review the current state of knowledge and propose that the induction of autophagy, in addition to modulation of the microbiota and coordinated effects on inflammation and epithelial cell biology, may be critical for the therapeutic effects associated with EEN. A better understanding of EEN treatment will provide new opportunities to restore gut homeostasis and prolong periods of remission, as well as provide new insights into the factors that trigger and perhaps prevent CD.

Introduction: Functional dyspepsia (FD), characterised by symptoms of epigastric pain or early satiety and post prandial distress, has been associated with duodenal eosinophilia, raising the possibility that it is driven by an environmental allergen. Non-coeliac gluten or wheat sensitivity (NCG/WS) has also been associated with both dyspeptic symptoms and duodenal eosinophilia, suggesting an overlap between these two conditions. The aim of this study was to evaluate the role of wheat (specifically gluten and fructans) in symptom reduction in participants with FD in a pilot randomized double-blind, placebo controlled, dietary crossover trial. Methods: Patients with Rome III criteria FD were recruited from a single tertiary centre in Newcastle, Australia. All were individually counselled on a diet low in both gluten and fermentable oligo-, di-, mono-saccharides, and polyols (FODMAPs) by a clinical dietitian, which was followed for four weeks (elimination diet phase). Those who had a &gt, 30% response to the run-in diet, as measured by the Nepean Dyspepsia Index, were then re-challenged with &lsquo, muesli&rsquo, bars containing either gluten, fructan, or placebo in randomised order. Those with symptoms which significantly reduced during the elimination diet, but reliably reappeared (a mean change in overall dyspeptic symptoms of &gt, 30%) with gluten or fructan re-challenge were deemed to have wheat induced FD. Results: Eleven participants were enrolled in the study (75% female, mean age 43 years). Of the initial cohort, nine participants completed the elimination diet phase of whom four qualified for the rechallenge phase. The gluten-free, low FODMAP diet led to an overall (albeit non-significant) improvement in symptoms of functional dyspepsia in the diet elimination phase (mean NDI symptom score 71.2 vs. 47.1, p = 0.087). A specific food trigger could not be reliably demonstrated. Conclusions: Although a gluten-free, low-FODMAP diet led to a modest overall reduction in symptoms in this cohort of FD patients, a specific trigger could not be identified. The modified Salerno criteria for NCG/WS identification trialled in this dietary rechallenge protocol was fit-for-purpose. However, larger trials are required to determine whether particular components of wheat induce symptoms in functional dyspepsia.

Background The pathogenesis of functional GI disorders (FGIDs) is uncertain. However, underlying immune activation and psychological distress has been documented in irritable bowel syndrome (IBS) and functional dyspepsia (FD). Epidemiological data from the UK suggest that FGIDs are linked to atopy and certain autoimmune diseases but this has not been confirmed. Aim To test if allergic or autoimmune diseases are independently associated with FGIDs, irrespective of psychological distress in a large population based study. Methods A total of 3542 people (mean age 57.9 years and 52.7% females) randomly selected from the Australian population, returned a mail survey (response rate = 43%). The survey asked about a physician diagnosis of autoimmune disease (scleroderma, psoriasis, rheumatoid arthritis and diabetes mellitus) or allergic conditions (asthma, food, pollen and/or animal allergy). The questionnaire assessed psychological distress and Rome III criteria for FD and IBS. Results Asthma, food, pollen and animal allergies, psoriasis and rheumatoid arthritis were univariately significantly associated with IBS and FD. Food allergy (OR = 1.66; 95% CI = 1.15-2.40, P = 0.007), psoriasis (OR = 1.81; 95% CI = 1.19-2.74, P = 0.006) and rheumatoid arthritis (OR = 1.68; 95% CI = 1.15-2.4, P = 0.007) were independent risk factors for IBS, controlling for age, gender and psychological distress. In FD, asthma (OR = 1.32; 95% CI = 1.04-1.68, P = 0.025) and food allergy (OR = 1.78; 95% CI = 1.28-2.49, P = 0.001) were independent predictors, controlling for age, sex and psychological distress. Conclusions There is evidence that both atopic and autoimmune diseases are risk factors for FGIDs, independent of psychological distress, differing in IBS and FD. This provides evidence that different peripheral pathways may be involved in the pathogenesis of certain FGIDs.

The type 2 family of taste receptors (T2Rs) detect and respond to bitter tastants. These receptors are expressed throughout the gastrointestinal (GI) tract, with location dependant roles. In the oral cavity, T2Rs are involved in the conscious perception of bitter tastants, while in the lower GI tract they have roles in chemoreception and regulation of GI function. Through these diverse roles, these receptors may be involved in modulating appetite and diet, with consequences for weight regulation and obesity. Interestingly, the concentration of T2Rs in the GI tract is greatest in the large intestine, the organ with the densest colonisation of bacteria. The gut microbiome has been the subject of intense research, as a plethora of roles linking microbiota to human health continue to be uncovered. Of particular interest is the microbial signature associated with obesity. Obesity is a leading health concern, and advances in our understanding of this disease are needed. Diet is a known modifiable factor in the development of obesity. However, diet only partially explains disease risk. Changes in microbial energy harvesting by the microbiota plays a role in obesity, and the composition of these energy harvesting populations may be controlled by taste receptors. This review explores T2Rs as a potential link between obesity and the human GI microbiome.

Wheat avoidance in the absence of celiac disease (CD) is common but occurrence of concurrent functional gastrointestinal disorders (FGIDs) in this group is uncertain. The aims of this study were to determine the prevalence of self-reported wheat or gluten sensitivity and doctor diagnosed CD in an Australian population, define the associated gastrointestinal (GI) symptoms and FGIDs, and determine the relationship between self-reported wheat sensitivity, demographic and medical factors. A total of 3542 people randomly selected from the Australian population returned a mail survey which contained questions on wheat avoidance, GI symptoms, demographic, medical, and lifestyle factors. We defined self-reported wheat sensitivity as people who reported gastrointestinal symptoms on ingestion of wheat based foods, but did not suffer from celiac disease, inflammatory bowel disease or colorectal cancer. Functional dyspepsia (FD) and irritable bowel syndrome (IBS) were diagnosed by Rome III criteria. CD status was self-reported. The prevalence of self-reported wheat sensitivity in this cohort was 14.9% (95% CI 13.7–16.2). The prevalence of CD was 1.2% (95%CI 0.8–1.6). Doctor diagnosed CD was significantly associated with a diagnosis of FD (OR 3.35, 95%CI 1.72–6.52) and IBS (OR 2.28, 95%CI 1.08–4.81). Those with self-reported wheat sensitivity were more likely to report multiple abdominal symptoms (of the 18 assessed) than those without (3.9 symptoms with self-reported wheat sensitivity vs. 1.6 without, p = 0.0001). In a multivariate analysis, self-reported wheat sensitivity was independently associated with IBS (OR 3.55, 95%CI 2.71–4.65) and FD (1.48, 95%CI 1.13–1.94). Self-reported wheat sensitivity is common, with a prevalence of 14.9% in this cohort. There is a strong association between both celiac disease and self-reported wheat sensitivity, and chronic gastrointestinal symptoms, as well as a diagnosis of FD and IBS.

There is a major unmet clinical need to identify pathways in inflammatory bowel disease (IBD) to classify patient disease activity, stratify patients that will benefit from targeted therapies such as anti-tumor necrosis factor (TNF), and identify new therapeutic targets. In this study, we conducted global transcriptome analysis to identify IBD-related pathways using colon biopsies, which highlighted the coagulation gene pathway as one of the most enriched gene sets in patients with IBD. Using this gene-network analysis across 14 independent cohorts and 1800 intestinal biopsies, we found that, among the coagulation pathway genes, plasminogen activator inhibitor-1 (PAI-1) expression was highly enriched in active disease and in patients with IBD who did not respond to anti-TNF biologic therapy and that PAI-1 is a key link between the epithelium and inflammation. Functionally, PAI-1 and its direct target, the fibrinolytic protease tissue plasminogen activator (tPA), played an important role in regulating intestinal inflammation. Intestinal epithelial cells produced tPA, which was protective against chemical and mechanical-mediated colonic injury in mice. In contrast, PAI-1 exacerbated mucosal damage by blocking tPA-mediated cleavage and activation of anti-inflammatory TGF-β, whereas the inhibition of PAI-1 reduced both mucosal damage and inflammation. This study identifies an immune-coagulation gene axis in IBD where elevated PAI-1 may contribute to more aggressive disease.

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract (GIT). Cigarette smoke (CS) exposure and chronic obstructive pulmonary disease (COPD) are risk factors for CD, although the mechanisms involved are poorly understood. We employed a mouse model of CS-induced experimental COPD and clinical studies to examine these mechanisms. Concurrent with the development of pulmonary pathology and impaired gas exchange, CS-exposed mice developed CD-associated pathology in the colon and ileum, including gut mucosal tissue hypoxia, HIF-2 stabilization, inflammation, increased microvasculature, epithelial cell turnover, and decreased intestinal barrier function. Subsequent smoking cessation reduced GIT pathology, particularly in the ileum. Dimethyloxaloylglycine, a pan-prolyl hydroxylase inhibitor, ameliorated CS-induced GIT pathology independently of pulmonary pathology. Prior smoke exposure exacerbated intestinal pathology in 2,4,6-trinitrobenzenesulfonic acid-induced (TNBS-induced) colitis. Circulating vascular endothelial growth factor, a marker of systemic hypoxia, correlated with CS exposure and CD in mice and humans. Increased mucosal vascularisation was evident in ileum biopsies from CD patients who smoke compared with nonsmokers, supporting our preclinical data. We provide strong evidence that chronic CS exposure and, for the first time to our knowledge, associated impaired gas exchange cause systemic and intestinal ischemia, driving angiogenesis and GIT epithelial barrier dysfunction, resulting in increased risk and severity of CD.

BACKGROUND: Eosinophilic esophagitis (EoE) is understood in terms of quantifiable histologic, endoscopic, and molecular features. There are limited data on interrelations of these features and their potential to identify distinct disease endotypes. METHODS: In this cross-sectional study, esophageal biopsies (n=185) from pediatric and adult EoE subjects across 10 sites associated with the Consortium of Eosinophilic Gastrointestinal Disease Researchers (CEGIR) were analyzed using the EoE Diagnostic Panel (EDP), a set of 95 informative transcripts. Histologic and endoscopic features were assessed by quantification of esophageal eosinophils, the EoE histology scoring system (HSS), and the EoE endoscopic reference score (EREFS). Associations among the various histologic, endoscopic, and molecular features were analyzed with Spearman correlation. Results were replicated in a biologically independent single center validation cohort of active EoE subjects (n=100). FINDINGS: The EDP showed intersite consistency, significant correlation with esophageal eosinophils (p

OBJECTIVES: Anti-cytolethal distending toxin B (CdtB) and anti-vinculin antibodies have been proposed as biomarkers that discriminate irritable bowel syndrome (IBS) diarrhea from inflammatory bowel disease; however, it is unknown whether they can also discriminate patients with IBS and IBS subtypes and functional dyspepsia (FD) from healthy individuals in the general population. We aimed to determine whether anti-CdtB and anti-vinculin can discriminate IBS and FD from health and from organic gastrointestinal (GI) disease. METHODS: Adults were enrolled from 2 Australian studies: (i) a random, population-based study (n = 331) with subjects diagnosed with IBS (n = 63) or FD (n = 61) by modified Rome III criteria or healthy control subjects (n = 246) who did not meet criteria for IBS and/or FD and (ii) an outpatient-based study with subjects diagnosed with IBS (n = 256) and/or FD (n = 55) or organic GI disease (n = 182) by an independent clinician. Serum levels of anti-CdtB/anti-vinculin antibodies were determined by enzyme-linked immunosorbent assay. RESULTS: There was a significantly higher mean value of anti-CdtB in FD vs healthy controls (mean = 2.46 [SD = 0.72] vs mean = 2.14 [SD = 0.77]; P = 0.005) and IBS/FD overlap vs healthy controls (mean = 2.47 [SD = 0.78] vs mean = 2.14 [SD = 0.77]; P = 0.02). There were no significant differences in anti-CdtB in IBS and FD outpatients or IBS/FD subgroups compared with patients with organic GI disease. In terms of anti-vinculin, there were no significant differences between IBS and FD and healthy controls or between IBS and FD and organic GI disease controls. DISCUSSION: We did not confirm that anti-CdtB/anti-vinculin discriminated IBS diarrhea from organic GI disease in Australian subjects. However, we did find higher anti-CdtB in FD and IBS/FD overlap vs healthy controls. Postinfectious FD may be more common than currently recognized.

© 2016 American Academy of Allergy, Asthma & Immunology Background Severe steroid-insensitive asthma is a substantial clinical problem. Effective treatments are urgently required, however, their development is hampered by a lack of understanding of the mechanisms of disease pathogenesis. Steroid-insensitive asthma is associated with respiratory tract infections and noneosinophilic endotypes, including neutrophilic forms of disease. However, steroid-insensitive patients with eosinophil-enriched inflammation have also been described. The mechanisms that underpin infection-induced, severe steroid-insensitive asthma can be elucidated by using mouse models of disease. Objective We sought to develop representative mouse models of severe, steroid-insensitive asthma and to use them to identify pathogenic mechanisms and investigate new treatment approaches. Methods Novel mouse models of Chlamydia, Haemophilus influenzae, influenza, and respiratory syncytial virus respiratory tract infections and ovalbumin-induced, severe, steroid-insensitive allergic airway disease (SSIAAD) in BALB/c mice were developed and interrogated. Results Infection induced increases in the levels of microRNA (miRNA)-21 (miR-21) expression in the lung during SSIAAD, whereas expression of the miR-21 target phosphatase and tensin homolog was reduced. This was associated with an increase in levels of phosphorylated Akt, an indicator of phosphoinositide 3-kinase (PI3K) activity, and decreased nuclear histone deacetylase (HDAC)2 levels. Treatment with an miR-21–specific antagomir (Ant-21) increased phosphatase and tensin homolog levels. Treatment with Ant-21, or the pan-PI3K inhibitor LY294002, reduced PI3K activity and restored HDAC2 levels. This led to suppression of airway hyperresponsiveness and restored steroid sensitivity to allergic airway disease. These observations were replicated with SSIAAD associated with 4 different pathogens. Conclusion We identify a previously unrecognized role for an miR-21/PI3K/HDAC2 axis in SSIAAD. Our data highlight miR-21 as a novel therapeutic target for the treatment of this form of asthma.

The epithelial barrier is the first innate defense of the gastrointestinal tract and selectively regulates transport from the lumen to the underlying tissue compartments, restricting the transport of smaller molecules across the epithelium and almost completely prohibiting epithelial macromolecular transport. This selectivity is determined by the mucous gel layer, which limits the transport of lipophilic molecules and both the apical receptors and tight junctional protein complexes of the epithelium. In vitro cell culture models of the epithelium are convenient, but as a model, they lack the complexity of interactions between the microbiota, mucous-gel, epithelium and immune system. On the other hand, in vivo assessment of intestinal absorption or permeability may be performed, but these assays measure overall gastrointestinal absorption, with no indication of site specificity. Ex vivo permeability assays using "intestinal sacs" are a rapid and sensitive method of measuring either overall intestinal integrity or comparative transport of a specific molecule, with the added advantage of intestinal site specificity. Here we describe the preparation of intestinal sacs for permeability studies and the calculation of the apparent permeability (Papp) of a molecule across the intestinal barrier. This technique may be used as a method of assessing drug absorption, or to examine regional epithelial barrier dysfunction in animal models of gastrointestinal disease.

Results from these studies reveal that some strains of Gram-positive bacteria exploit hypoxia-inducible factor-regulated platelet-activating factor receptor as a means for translocation through intestinal epithelial cells., Mucosal surfaces, such as the lung and intestine, are lined by a monolayer of epithelia that provides tissue barrier and transport function. It is recently appreciated that a common feature of inflammatory processes within the mucosa is hypoxia (so-called inflammatory hypoxia). Given the strong association between bacterial translocation and mucosal inflammatory disease, we hypothesized that intestinal epithelial hypoxia influences bacterial translocation. Initial studies revealed that exposure of cultured intestinal epithelia to hypoxia (pO2, 20 torr; 24–48 h) resulted in a increase of up to 40-fold in the translocation of some strains of Gram-positive bacteria, independently of epithelial barrier function. A screen of relevant pathway inhibitors identified a prominent role for the platelet-activating factor receptor (PAFr) in hypoxia-associated bacterial translocation, wherein pharmacologic antagonists of PAFr blocked bacterial translocation by as much as 80 ± 6%. Extensions of these studies revealed that hypoxia prominently induces PAFr through a hypoxia-inducible factor (HIF)-dependent mechanism. Indeed, HIF and PAFr loss of function studies (short hairpin RNA) revealed that apically expressed PAFr is central to the induction of translocation for the Gram-positive bacteria Enterococcus faecalis. Together, these findings reveal that some strains of Gram-positive bacteria exploit HIF-regulated PAFr as a means for translocation through intestinal epithelial cells.