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OBJECTIVES: Colorectal carcinoma remains one of the most common malignancies worldwide. Colonoscopy screening is most effective for early detection and tumour prevention and is currently recommended in Europe for adults aged over 50 years. However, given that an increasing proportion of patients are diagnosed before the age of 50, we set out to determine the detection rate of colorectal carcinoma in patients younger than 50 years and to determine the best threshold for starting colonoscopy screening. METHODS: Single-centre, retrospective cohort study of all colonoscopies performed, regardless of indication, in our department at a tertiary Swiss university hospital in patients aged ≥18 and

Commensal intestinal bacteria shape our microbiome and have decisive roles in preserving host metabolic and immune homeostasis. They conspicuously impact disease development and progression, including amyloid-beta (Aβ) and alpha (α)-synuclein pathology in neurodegenerative diseases, conveying the importance of the brain–gut–microbiome axis in such conditions. However, little is known about the longitudinal microbiome landscape and its potential clinical implications in other protein misfolding disorders, such as prion disease. We investigated the microbiome architecture throughout prion disease course in mice. Fecal specimens were assessed by 16S ribosomal RNA sequencing. We report a temporal microbiome signature in prion disease and uncovered alterations in Lachnospiraceae, Ruminococcaceae, Desulfovibrionaceae, and Muribaculaceae family members in this disease. Moreover, we determined the enrichment of Bilophila, a microorganism connected to cognitive impairment, long before the clinical manifestation of disease symptoms. Based on temporal microbial abundances, several associated metabolic pathways and resulting metabolites, including short-chain fatty acids, were linked to the disease. We propose that neuroinflammatory processes relate to perturbations of the intestinal microbiome and metabolic state by an interorgan brain–gut crosstalk. Furthermore, we describe biomarkers possibly suitable for early disease diagnostics and anti-prion therapy monitoring. While our study is confined to prion disease, our discoveries might be of equivalent relevance in other proteinopathies and central nervous system pathologies.

Background: The increasing presence of plastics in the human diet is raising public concern about the potential risks posed by nanoplastic (NP) particles, which can emerge from the degradation of plastic debris. NP ingestion poses particular risks to individuals with inflammatory bowel disease (IBD), as compromised epithelial barriers may facilitate NP translocation. Methods: In vitro, bone-marrow-derived macrophages (BMDMs) were exposed to 25 nm polymethacrylate (PMMA) or 50 nm polystyrene (PS) particles to assess morphological changes and alterations in pro- and anti-inflammatory gene expression. In vivo, mice received PMMA NP particles for 6 months before acute dextran sodium sulfate (DSS) colitis was induced to investigate NP impacts on intestinal health and inflammation. Results: PMMA and PS NP exposure in BMDMs induced morphological changes indicative of a proinflammatory phenotype characterized by enlarged amoeboid cell shapes. It also triggered an inflammatory response, indicated by increased expression of proinflammatory cytokines such as Tnfa and Il6. Unexpectedly, long-term PMMA NP administration did not affect the intestinal epithelial barrier or exacerbate acute DSS-induced colitis in mice. Colonoscopy and histological analysis revealed no NP-related changes, suggesting adverse effects on intestinal health or inflammation. Conclusion: Our findings from animal models offer some reassurance to IBD patients regarding the effects of NP ingestion. However, variations in lifestyle and dietary habits may lead to significantly higher plastic intake in certain individuals, raising concerns about potential long-term gastrointestinal effects of lifelong plastic consumption.

Background & Aims: Glycoprotein (GP)96 is an endoplasmic reticulum–resident master chaperone for cell surface receptors including the Wnt co-receptors low-density lipoprotein-receptor–related protein 5/6. Intestinal epithelial cell (IEC)-specific deletion of Gp96 is embryonically lethal. However, the role of GP96 in adult intestinal tissue and especially within the intestinal stem cell (ISC) niche is unknown. Here, we investigated how GP96 loss interferes with intestinal homeostasis by compromising viability, proliferation, and differentiation of IECs. Methods: Tamoxifen was used to induce Cre-mediated deletion of Gp96 in GP96-VillincreERT2 (Cre recombinase-Estrogen-Receptor Transgene 2) mice and intestinal organoids. With H&E and immunofluorescence staining we assessed alterations in intestinal morphology and the presence and localization of IEC types. Real-time polymerase chain reaction and Western blot analysis were performed to explore the molecular mechanisms underlying the severe phenotype of Gp96 KO mice and organoids. Results: IEC-specific deletion of Gp96 in adult mice resulted in a rapid degeneration of the stem cell niche, followed by complete eradication of the epithelial layer and death within a few days. These effects were owing to severe defects in ISC renewal and premature ISC differentiation, which resulted from defective Wnt and Notch signaling. Furthermore, depletion of GP96 led to massive induction of endoplasmic reticulum stress. Although effects on ISC renewal and adequate differentiation were partly reversed upon activation of Wnt/Notch signaling, viability could not be restored, indicating that reduced viability was mediated by other mechanisms. Conclusions: Our work shows that GP96 plays a fundamental role in regulating ISC fate and epithelial regeneration and therefore is indispensable for maintaining intestinal epithelial homeostasis.

The overall pathogenesis of bladder cancer is still unknown. The microbiota has been shown to play a critical role in the development of different types of cancer. Nevertheless, the role of the microbiota in the development of bladder cancer is still not fully discovered. This review aims to assess the urinary, vaginal, and intestinal microbiota analyzed from the bacterial, viral, and fungal compartments of bladder cancer patients compared with the microbiota of controls to reveal possible differences. A systematic review according to the PRISMA guidelines will be performed. The findings will be presented in narrative form as well as in tables and graphs.

Abstract Background Genetic variations within the regulatory region of the gene encoding NOD-like receptor pyrin domain containing 3 (NLRP3) have been associated with Crohn’s Disease (CD). NLRP3 is part of the NLRP3-inflammasome that mediates the maturation of IL-1β and IL-18. Carrying the major allele of the single nucleotide polymorphisms (SNPs) rs10733113, rs4353135 and rs55646866 is associated with an increased risk for CD. We here studied the impact of these polymorphisms on clinical characteristics in patients of the Swiss IBD Cohort Study (SIBDCS). Methods We included 981 Crohn’s disease (CD) patients and 690 ulcerative colitis (UC) patients of the SIBDCS. We analyzed whether three CD-associated NLRP3 polymorphisms have an impact on the clinical disease course in these patients. Results In CD patients presence of the major allele (G) of rs10733113 was associated with less surgeries and lower maximal CDAI and a similar trend was observed for rs55646866 and rs4353135. Presence of the major allele of all three SNPs was negatively correlated to maximal CDAI. In UC patients homozygous genotype for the major allele (CC) for rs55646866 was associated with a higher age at diagnosis and a higher MTWAI index. Homozygous genotype for the major allele of all three polymorphisms was associated with a higher number of ambulatory visits and longer hospital stays. Conclusions In CD patients presence of the major allele of all three polymorphisms was associated with markers of a less severe disease course, while in UC the homozygous genotype for all major alleles suggested a more severe disease activity.

Background and Aims: Local extracellular acidification is associated with several conditions, such as ischemia, cancer, metabolic disease, respiratory diseases, and inflammatory bowel disease (IBD). Several recent studies reported a link between IBD and a family of pH-sensing G protein-coupled receptors. Our previous studies point to an essential role for OGR1 (GPR68) in the modulation of intestinal inflammation and fibrosis. In the current study, we evaluated the effects of a novel OGR1 inhibitor in murine models of colitis. Methods: The effects of a novel small-molecule OGR1 inhibitor were assessed in the acute and chronic dextran sulfate sodium (DSS) murine models of colitis. Macroscopic disease indicators of intestinal inflammation were evaluated, and epithelial damage and immune cell infiltration and proliferation were assessed by immunohistochemistry. Results: The OGR1 inhibitor ameliorated clinical parameters in acute and chronic DSS-induced colitis. In mice treated with the OGR1 inhibitor, endoscopy showed no thickening and normal vascularity, while fibrin was not detected. Histopathological findings revealed a decrease in severity of colonic inflammation in the OGR1 inhibitor group when compared to vehicle-DSS controls. In OGR1 inhibitor-treated mice, staining for the macrophage marker F4/80 and cellular proliferation marker Ki-67 revealed a reduction of infiltrating macrophages and slightly enhanced cell proliferation, respectively. This was accompanied by a reduction in pro-inflammatory cytokines, TNF and IL-6, and the fibrosis marker TGF-β1. Conclusion: This is the first report providing evidence that a pharmacological inhibition of OGR1 has a therapeutic effect in murine colitis models. Our data suggest that targeting proton-sensing OGR1 using specific small-molecule inhibitors may be a novel therapeutic approach for the treatment of IBD.

Introduction The human microbiota, the community of micro-organisms in different cavities, has been increasingly linked with inflammatory and neoplastic diseases. While investigation into the gut microbiome has been robust, the urinary microbiome has only recently been described. Investigation into the relationship between bladder cancer (BC) and the bladder and the intestinal microbiome may elucidate a pathophysiological relationship between the two. The bladder or the intestinal microbiome or the interplay between both may also act as a non-invasive biomarker for tumour behaviour. While these associations have not yet been fully investigated, urologists have been manipulating the bladder microbiome for treatment of BC for more than 40 years, treating high grade non-muscle invasive BC (NMIBC) with intravesical BCG immunotherapy. Neither the association between the microbiome sampled directly from bladder tissue and the response to BCG-therapy nor the association between response to BCG-therapy with the faecal microbiome has been studied until now. A prognostic tool prior to initiation of BCG-therapy is still needed.Methods and analysis In patients with NMIBC bladder samples will be collected during surgery (bladder microbiome assessment), faecal samples (microbiome assessment), instrumented urine and blood samples (biobank) will also be taken. We will analyse the microbial community by 16S rDNA gene amplicon sequencing. The difference in alpha diversity (diversity of species within each sample) and beta diversity (change in species diversity) between BCG-candidates will be assessed. Subgroup analysis will be performed which will lead to the development of a clinical prediction model estimating risk of BCG-response.Ethics and dissemination The study has been approved by the Cantonal Ethics Committee Zurich (2021-01783) and it is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice. Study results will be disseminated through peer-reviewed journals and national and international scientific conferences.Trial registration number NCT05204199.

Background and Aims: The majority of patients treated with anti-tumor necrosis factor (TNF) therapy develop anti-drug antibodies (ADAs), which might result in loss of treatment efficacy. Strict guidelines on measuring trough levels (TLs) and ADA in clinical routine do not exist. To provide real-world data, we took advantage of our tertiary inflammatory bowel disease (IBD) center patient cohort and determined indicators for therapeutic drug monitoring (TDM) and actual consequences in patient care. Methods: We retrospectively collected clinical data of 104 IBD patients treated with infliximab or adalimumab in our IBD clinic. Patients with TL and ADA measurements between June 2015 and February 2018 were included. Results: The main reason for determining TL was increased clinical disease. Subtherapeutic TLs were found in 33 patients, therapeutic TLs in 33 patients, and supratherapeutic TLs in 38 patients. Adjustments in anti-TNF therapy occurred more frequently (p = 0.01) in patients with subtherapeutic TL (24 of 33 patients; 73%) as compared to patients with therapeutic and supratherapeutic TLs (26 of 71 patients; 37%). No correlation could be found between TL and disease activity (p = 0.16). Presence of ADA was found in 16 patients, correlated with the development of infusion reactions (OR: 10.6, RR: 5.4, CI: 2.9–38.6), and was associated with subtherapeutic TL in 15 patients (93.8%). Treatment adaptations were based on TL and/or ADA presence in 36 of 63 patients. Conclusions: TDM showed significant treatment adaptations in patients with subtherapeutic TL. Conversely, in patients with therapeutic and supratherapeutic TLs, reasons for adaptations were based on considerations other than TL, such as clinical disease activity. Further studies should focus on decision-making in patients presenting with supratherapeutic TL in remission.

Introduction: The pathophysiology of inflammatory bowel disease (IBD) is incompletely understood. Current concepts imply that environmental factors (EFs) trigger disease onset as well as flares in genetically susceptible individuals. Objective: The objective of this study is to analyze the association between IBD and various EFs, which may influence the pathogenesis of the disease. Methods: 2,294 patients from the Swiss IBD Cohort Study (SIBDCS) received a questionnaire regarding EF including mode of delivery, breastfeeding, animals in household, and place of residence. The control group comprised patients’ childhood friends, who grew up in a similar environment (“friends cohort”). Results: A total of 1,111 questionnaires were returned from SIBDCS patients (response rate: 48.4%). Breastfeeding for

Background/Aims: Among the severe immune-related adverse events (irAEs) that occur with immune checkpoint inhibitor (ICI) therapy, colitis is the most frequent one. This study aimed at describing the experience from the largest gastroenterology unit in Switzerland with immune checkpoint inhibitor-associated colitis (ICIAC), its clinical presentation, management, and outcomes. Methods: We performed a retrospective review of patients who were referred for the evaluation of ICIAC between January 2011 and October 2018 to the Division of Gastroenterology and Hepatology, University Hospital Zurich. Results: Thirty-three patients with immune-related colitis grade 3 or 4 met the inclusion criteria and were analyzed in detail: All patients had diarrhea, 64% had abdominal pain, 42% had bloody stool, 27% had emesis, and 18% developed fever. In total, 33% were successfully treated with corticosteroids alone; 66% were steroid-refractory and treated with infliximab or vedolizumab. Two of these patients developed severe complications requiring surgery. All patients reached complete remission of ICIAC and its symptoms. At colonoscopy, ulcerations were seen in 37% of steroid-refractory versus 63% of steroid-responsive cases. Deep histological ulcerations invading the submucosa were only present in steroid-refractory cases. Conclusion: ICIAC is a severe irAE which frequently requires high-dose steroids and a close follow-up due to deleterious complications. The detection of histologically diagnosed deep ulcerations may predict a steroid-refractory course and may warrant early application of infliximab. However, larger studies are required to confirm our findings.

Background Integrin αvβ6 is a heterodimeric cell surface protein whose cellular expression is determined by the availability of the integrin β6 subunit (ITGB6). It is expressed at very low levels in most organs during tissue homeostasis but shows highly upregulated expression during the process of tumorigenesis in many cancers of epithelial origin. Notably, enhanced expression of integrin αvβ6 is associated with aggressive disease and poor prognosis in numerous carcinoma entities. Integrin αvβ6 is one of the major physiological activators of transforming growth factor-β (TGF-β), which has been shown to inhibit the antitumor T-cell response and cause resistance to immunotherapy in mouse models of colorectal and mammary cancer. In this study, we investigated the effect of ITGB6 expression and antibody-mediated integrin αvβ6 inhibition on the tumor immune response in colorectal cancer.Methods Using orthotopic and heterotopic tumor cell injection, we assessed the effect of ITGB6 on tumor growth and tumor immune response in wild type mice, mice with defective TGF-β signaling, and mice treated with anti-integrin αvβ6 antibodies. To examine the effect of ITGB6 in human colorectal cancer, we analyzed RNAseq data from the colon adenocarcinoma dataset of The Cancer Genome Atlas (TCGA-COAD).Results We demonstrate that expression of ITGB6 is an immune evasion strategy in colorectal cancer, causing inhibition of the antitumor immune response and resistance to immune checkpoint blockade therapy by activating latent TGF-β. Antibody-mediated inhibition of integrin αvβ6 sparked a potent cytotoxic T-cell response and overcame resistance to programmed cell death protein 1 (PD-1) blockade therapy in ITGB6 expressing tumors, provoking a drastic increase in anti-PD-1 treatment efficacy. Further, we show that the majority of tumors in patients with colorectal cancer express sufficient ITGB6 to provoke inhibition of the cytotoxic T-cell response, indicating that most patients could benefit from integrin αvβ6 blockade therapy.Conclusions These findings propose inhibition of integrin αvβ6 as a promising new therapy for colorectal cancer, which blocks tumor-promoting TGF-β activation, prevents tumor exclusion of cytotoxic T-cells and enhances the efficacy of immune checkpoint blockade therapy.

BackgroundLittle is known about the impact of ostomy formation in inflammatory bowel disease patients on course of disease, psychological well-being, quality of life and working capacity.MethodsWe analyzed patients over a follow-up of up to 16 years in the Swiss inflammatory bowel disease cohort study (SIBDCS) with prospective data collection. We compared Ulcerative colitis and Crohn's disease patients with and without ostomy as well as permanent and closed stoma formation before and after surgery, investigating disease activity, psychological wellbeing and working capacity in a case-control design.ResultsOf 3825 SIBDCS patients, 176 with ostomy were included in the study and matched with 176 patients without ostomy using propensity score, equaling 352 patients for the analysis. As expected, we observed a lower mean and maximal disease activity in patients after stoma surgery compared with control patients without stoma. Overall, psychological wellbeing in patients with stomas vs. controls as well as patients with permanent vs. closed stoma was similar in terms of disease-specific quality of life (total score of the Inflammatory Bowel Disease Quality of Life questionnaire), psychological distress (total score of the Hospital Anxiety and Depression Scale), and stress at work (effort-reward-imbalance ratio), with the exception of a higher Posttraumatic Diagnostic Scale total score in patient with vs. without stoma. Compared to IBD patients without stoma, the adverse impact on working capacity in overall stoma IBD patients appeared to be modest. However we observe a significantly higher reduction in working capacity in permanent vs. closed stoma in CD but not UC patients.ConclusionAs to be expected, IBD patients may benefit from closed and permanent stoma application. Stoma surgery appears to only modestly impact working capacity. Importantly, stoma surgery was not associated with adverse psychological outcomes, with comparable psychological well-being regardless of presence and type of stoma.

Abstract Asthma is a heterologous disease that is influenced by complex interactions between multiple environmental exposures, metabolism, and host immunoregulatory processes. Specific metabolites are increasingly recognized to influence respiratory inflammation. However, the role of protein‐derived metabolites in regulating inflammatory responses in the lung are poorly described. The aims of the present study were to quantify polyamine levels in bronchoalveolar lavages (BALs) from healthy volunteers and asthma patients, and to evaluate the impact of each polyamine on inflammatory responses using in vitro models and in a house dust mite (HDM)‐induced respiratory allergy model. Spermidine levels were decreased, while cadaverine levels were increased in BALs from asthma patients compared to healthy controls, using Ultra Performance Liquid Chromatography (UPLC). Both spermine and spermidine inhibit lipopolysaccharide (LPS)‐induced cytokine secretion from human peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) in vitro. In addition, oral gavage with spermine or spermidine modulate HDM‐induced cell infiltration, cytokine secretion, and epithelial cell tight junction expression in murine models. Spermidine also reduces airway hyper‐responsiveness. These results suggest that modulation of polyamine metabolism, in particular spermidine, is associated with respiratory inflammation and these molecules and pathways should be further explored as biomarkers of disease and potential targets for novel therapies.

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers and leading cause of cancer-related deaths worldwide. In recent years, there has been a growing realisation that lifestyle plays a major role for CRC development and that intestinal microbiota, which are shaped by lifestyle and nutrition habits, may be critically involved in the pathogenesis of CRC. Although the precise mechanisms for how the microbiota contribute to CRC development and progression remain elusive, increasing evidence suggests a direct causative role for the intestinal microbiota in modulating signalling pathways, anti-tumour immune responses and cell proliferation. Recent advances in understanding host-microbe interactions have shed light onto the putative use of intestinal microbiota as a powerful tool in CRC diagnosis and therapy. Here, we will discuss the role of the intestinal microbiota in CRC pathogenesis, their potential utility as diagnostic markers, and consider how microbes could be used in therapeutic approaches for the treatment of CRC. Keywords: Colorectal cancer (CRC), Intestinal microbiota, Nutrition, Pathogenesis, Diagnosis, Therapy

Nonalcoholic steatohepatitis (NASH), a primary cause of liver disease, leads to complications such as fibrosis, cirrhosis, and carcinoma, but the pathophysiology of NASH is incompletely understood. Epstein-Barr virus-induced G protein-coupled receptor 2 (EBI2) and its oxysterol ligand 7α,25-dihydroxycholesterol (7α,25-diHC) are recently discovered immune regulators. Several lines of evidence suggest a role of oxysterols in NASH pathogenesis, but rigorous testing has not been performed. We measured oxysterol levels in the livers of NASH patients by LC-MS and tested the role of the EBI2-7α,25-diHC system in a murine feeding model of NASH. Free oxysterol profiling in livers from NASH patients revealed a pronounced increase in 24- and 7-hydroxylated oxysterols in NASH compared with controls. Levels of 24- and 7-hydroxylated oxysterols correlated with histological NASH activity. Histological analysis of murine liver samples demonstrated ballooning and liver inflammation. No significant genotype-related differences were observed in Ebi2−/− mice and mice with defects in the 7α,25-diHC synthesizing enzymes CH25H and CYP7B1 compared with wild-type littermate controls, arguing against an essential role of these genes in NASH pathogenesis. Elevated 24- and 7-hydroxylated oxysterol levels were confirmed in murine NASH liver samples. Our results suggest increased bile acid synthesis in NASH samples, as judged by the enhanced level of 7α-hydroxycholest-4-en-3-one and impaired 24S-hydroxycholesterol metabolism as characteristic biochemical changes in livers affected by NASH.

Background & Aims: Hypoxia-associated pathways influence the development of inflammatory bowel disease. Adaptive responses to hypoxia are mediated through hypoxia-inducible factors, which are regulated by iron-dependent hydroxylases. Signals reflecting oxygen tension and iron levels in enterocytes regulate iron metabolism. Conversely, iron availability modulates responses to hypoxia. In the present study we sought to elucidate how iron influences the responses to hypoxia in the intestinal epithelium. Methods: Human subjects were exposed to hypoxia, and colonic biopsy specimens and serum samples were collected. HT-29, Caco-2, and T84 cells were subjected to normoxia or hypoxia in the presence of iron or the iron chelator deferoxamine. Changes in inflammatory gene expression and signaling were assessed by quantitative polymerase chain reaction and Western blot. Chromatin immunoprecipitation was performed using antibodies against nuclear factor (NF)-κB and primers for the promoter of tumor necrosis factor (TNF) and interleukin (IL)1β. Results: Human subjects presented reduced levels of ferritin in the intestinal epithelium after hypoxia. Hypoxia reduced iron deprivation–associated TNF and IL1β expression in HT-29 cells through the induction of autophagy. Contrarily, hypoxia triggered TNF and IL1β expression, and NF-κB activation in Caco-2 and T84 cells. Iron blocked autophagy in Caco-2 cells, while reducing hypoxia-associated TNF and IL1β expression through the inhibition of NF-κB binding to the promoter of TNF and IL1β. Conclusions: Hypoxia promotes iron mobilization from the intestinal epithelium. Hypoxia-associated autophagy reduces inflammatory processes in HT-29 cells. In Caco-2 cells, iron uptake is essential to counteract hypoxia-induced inflammation. Iron mobilization into enterocytes may be a vital protective mechanism in the hypoxic inflamed mucosa. Keywords: Inflammatory Bowel Disease, Autophagy, Deferoxamine, Caco-2

Abstract Background Tissue inflammation in inflammatory bowel diseases (IBD) is associated with a decrease in local pH. The gene encoding G-protein-coupled receptor 65 (GPR65) has recently been reported to be a genetic risk factor for IBD. In response to extracellular acidification, proton activation of GPR65 stimulates cAMP and Rho signalling pathways. We aimed to analyse the clinical and functional relevance of the GPR65 associated single nucleotide polymorphism (SNP) rs8005161. Methods 1138 individuals from a mixed cohort of IBD patients and healthy volunteers were genotyped for SNPs associated with GPR65 (rs8005161, rs3742704) and galactosylceramidase (rs1805078) by Taqman SNP assays. 2300 patients from the Swiss IBD Cohort Study (SIBDC) were genotyped for rs8005161 by mass spectrometry based SNP genotyping. IBD patients from the SIBDC carrying rs8005161 TT, CT, CC and non-IBD controls (CC) were recruited for functional studies. Human CD14+ cells were isolated from blood samples and subjected to an extracellular acidic pH shift, cAMP accumulation and RhoA activation were measured. Results In our mixed cohort, but not in SIBDC patients, the minor variant rs8005161 was significantly associated with UC. In SIBDC patients, we observed a consistent trend in increased disease severity in patients carrying the rs8005161-TT and rs8005161-CT alleles. No significant differences were observed in the pH associated activation of cAMP production between IBD (TT, CT, WT/CC) and non-IBD (WT/CC) genotype carriers upon an acidic extracellular pH shift. However, we observed significantly impaired RhoA activation after an extracellular acidic pH shift in IBD patients, irrespective of the rs8005161 allele. Conclusions The T allele of rs8005161 might confer a more severe disease course in IBD patients. Human monocytes from IBD patients showed impaired pH associated RhoA activation upon an acidic pH shift.

Human studies show that in addition to skin barrier and immune cell dysfunction, both the cutaneous and the gut microbiota can influence the pathogenesis of atopic diseases. There is currently no data on the gut-skin axis in allergic canines. Therefore, the aim of this study was to assess the bacterial diversity and composition of the gut microbiome in dogs with atopic dermatitis (AD). Stool samples from adult beagle dogs (n = 3) with spontaneous AD and a healthy control group (n = 4) were collected at Days 0 and 30. After the first sampling, allergic dogs were orally dosed on a daily basis with oclacitinib for 30 days, and then re-sampled. Sequencing of the V3–V4 region of the 16S rRNA gene was performed on the Illumina MiSeq platform and the data were analyzed using QIIME2. The atopic dogs had a significantly lower gut microbiota alpha-diversity than healthy dogs (p = 0.033). In healthy dogs, a higher abundance of the families Lachnospiraceae (p = 0.0006), Anaerovoracaceae (p = 0.006) and Oscillospiraceae (p = 0.021) and genera Lachnospira (p = 0.022), Ruminococcustorques group (p = 0.0001), Fusobacterium (p = 0.022) and Fecalibacterium (p = 0.045) was seen, when compared to allergic dogs. The abundance of Conchiformibius (p = 0.01), Catenibacterium spp. (p = 0.007), Ruminococcus gnavus group (p = 0.0574) and Megamonas (p = 0.0102) were higher in allergic dogs. The differences in alpha-diversity and on the compositional level remained the same after 1 month, adding to the robustness of the data. Additionally, we could also show that a 4-week treatment course with oclacitinib was not associated with changes in the gut microbiota diversity and composition in atopic dogs. This study suggests that alterations in the gut microbiota diversity and composition may be associated with canine AD. Large-scale studies preferably associated to a multi-omics approach and interventions targeting the gut microbiota are needed to confirm these results.

Lipid emulsions are crucial for life-saving total parenteral nutrition (TPN). Their composition provides a high amount of essential fatty acids and calories for millions of patients with serious diseases. Nevertheless, several TPN-mediated side-effects have been reported in over 90% of patients. This project aimed to investigate the effect of a high amount of ω3 fatty acids (Omegaven®) emulsion vs. a high amount of ω6 fatty acids (Intralipid®) emulsions on the endothelial barrier function. EA.hy926 cell line was cultured and incubated with 0.01, 0.1, and 1 mM lipid emulsions. The influence of these lipid emulsions on the barrier function was assessed using ECIS technology, immunofluorescent microscopy, viability measurements by flow cytometry, multiplex cytokines analysis, and qRT-PCR. BODIPY staining confirmed the uptake of fatty acids by endothelial cells. ECIS measurements demonstrated that a high concentration of Omegaven® prevents barrier formation and impairs the barrier function by inducing cell detachment. Moreover, the expression of VE-cadherin and F-actin formation showed a reorganization of the cell structure within 2 h of 1 mM Omegaven® addition. Interestingly, the study’s findings contradict previous studies and revealed that Omegaven® at high concentration, but not Intralipid, induces cell detachments, impairing endothelial cells’ barrier function. In summary, our studies shed new light on the effect of lipid emulsions on the endothelium.

Colorectal cancers (CRCs) remain one of the most common and challenging neoplasia in the Western world. The response rate of immunotherapeutic treatment approaches in a subset of advanced CRCs is remarkable and has sustainably changed treatment regimens. Unfortunately, currently available immunotherapeutics only displayed significant antitumoral activity – in terms of progression free survival (PFS) and objective response rate (ORR) – in microsatellite instability-high (MSI-H)/DNA mismatch repair deficient (dMMR) CRCs. Subsequently, these remarkable results had led to the US Food and Drug Administration’s approval of both immune checkpoint inhibitors (ICIs) pembrolizumab and nivolumab in the treatment of advanced MSI-H/dMMR CRCs. However, in microsatellite stable (MSS)/DNA mismatch repair proficient (pMMR) CRCs, ICIs have clearly failed to meet their expectations and are therefore not considered effective. As the vast majority of CRCs display a molecular MSS/pMMR profile, current treatment approaches endeavor to improve tumor immunogenicity that consecutively leads to increased proinflammatory cytokine levels as well as tumor infiltrating T-cells, which in turn may be targeted by various immunotherapeutic agents. Therefore, ongoing studies are investigating novel synergistic therapy modalities and approaches to overcome a “cold” to “hot” tumor conversion in MSS/pMMR CRCs. In this review, we summarize the efficacy and possible immune-related adverse events as well as novel therapeutic approaches of ICIs in the treatment of MSI-H/dMMR and MSS/pMMR CRCs.

Crohn’s disease (CD) is a major form of inflammatory bowel disease characterized by transmural inflammation along the alimentary tract. Changes in the microbial composition and reduction in species diversity are recognized as pivotal hallmarks in disease dynamics, challenging the gut barrier function and shaping a pathological immune response in genetically influenced subjects. The purpose of this review is to delve into the modification of the gut microbiota cluster network during CD progression and to discuss how this shift compromises the gut barrier integrity, granting the translocation of microbes and their products. We then complete the scope of the review by retracing gut microbiota dysbiosis interactions with the main pathophysiologic factors of CD, starting from the host’s genetic background to the immune inflammatory and fibrotic processes, providing a standpoint on the lifestyle/exogenous factors and the potential benefits of targeting a specific gut microbiota.

Background: Crohn’s disease (CD) may progress from an inflammatory to a stricturing or penetrating disease phenotype. The aim of our study was to identify single nucleotide polymorphisms (SNPs) that predict disease progression in patients of the Swiss IBD Cohort Study (SIBDCS). Methods: We applied a multi-state Markov model for progression behavior of CD with three behavioral states according to the Montreal classification. The model considered transition from B1 to B2/B3 or from B2 to B3 stage. Model dynamics were summarized with transition intensities by including the effect of SNPs and calculating transition intensities for each SNP. Results: We included 1276 CD patients [669 (52.4%) B1, 248 (19.4%) B2, 359 (28.1%) B3 patients] with a median follow-up of 6.8 (interquartile range = 3.6–9.1; range 0–11.6) years. Probability for a B1 patient to develop a stenosis (B1 to B2, q = 0.033) was twice as much as compared to developing a penetrating complication (B3) during the disease course. In contrast, the probability of entering B3 stage was similar regardless of whether antecedent stricture was present (B2 to B3, q = 0.016) or not (B1 to B3, q = 0.016). We identified SNPs within the gene loci encoding ZMIZ1, LOC105373831 and KSR1 as carrying the highest risk for progression to B3, while the presence of SNPs within gene loci TNFSF15 and CEBPB-PTPN1 protected from progression to B2 or B3. Conclusion: We identified new genetic risk factors that can predict disease course in CD patients. A closer understanding on the functional impact of these genetic variations might improve our treatment options finally to prevent disease progression in CD patients.

Protein tyrosine phosphatase non-receptor type 2 (PTPN2) plays a pivotal role in immune homeostasis and has been associated with human autoimmune and chronic inflammatory diseases. Though PTPN2 is well-characterized in lymphocytes, little is known about its function in innate immune cells. Our findings demonstrate that dendritic cell (DC)-intrinsic PTPN2 might be the key to explain the central role for PTPN2 in the immune system to maintain immune tolerance. Partial genetic PTPN2 ablation in DCs resulted in spontaneous inflammation, particularly in skin, liver, lung and kidney 22 weeks post-birth. DC-specific PTPN2 controls steady-state immune cell composition and even incomplete PTPN2 deficiency in DCs resulted in enhanced organ infiltration of conventional type 2 DCs, accompanied by expansion of IFNγ-producing effector T-cells. Consequently, the phenotypic effects of DC-specific PTPN2 deficiency were abolished in T-cell deficient Rag knock-out mice. Our data add substantial knowledge about the molecular mechanisms to prevent inflammation and maintain tissue tolerance.

Background: Inflammatory bowel disease (IBD) needs early interventions and an individual specialist–patient relationship. Distance from a tertiary IBD center might affect patient’s disease course and outcome. We investigated whether the patient-to-specialist distance has an impact on the disease course using the well-defined patient collective of the Swiss Inflammatory Bowel Disease Cohort Study (SIBDCS). Methods: Patient’s home address at diagnosis (postal zip code) was extracted from the SIBDCS database. Distance between each zip code and the nearest located IBD specialist center was calculated and classified into the following three sections based on proximity: 35 km (group 3). Results: Our study included in total 408 IBD patients [234 Crohn’s disease (CD), 154 ulcerative colitis (UC), 20 IBD unclassified (IBDU)]. Median age was lowest in group 2 at diagnosis (G1: 28 years; G2: 21 years, G3: 26 years, p

Summary: Variants in the gene locus encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) are associated with inflammatory disorders, including inflammatory bowel diseases, rheumatoid arthritis, and type 1 diabetes. The anti-inflammatory role of PTPN2 is highlighted by the fact that PTPN2-deficient mice die a few weeks after birth because of systemic inflammation and severe colitis. However, the tissues, cells, and molecular mechanisms that contribute to this phenotype remain unclear. Here, we demonstrate that myeloid cell-specific deletion of PTPN2 in mice (PTPN2-LysMCre) promotes intestinal inflammation but protects from colitis-associated tumor formation in an IL-1β-dependent manner. Elevated levels of mature IL-1β production in PTPN2-LysMCre mice are a consequence of increased inflammasome assembly due to elevated phosphorylation of the inflammasome adaptor molecule ASC. Thus, we have identified a dual role for myeloid PTPN2 in directly regulating inflammasome activation and IL-1β production to suppress pro-inflammatory responses during colitis but promote intestinal tumor development.

Background: The single nucleotide polymorphism (SNP) rs1042058 within the gene locus encoding tumor progression locus 2 (TPL2) has been recently identified as a risk gene for inflammatory bowel disease (IBD). TPL2 has been shown to regulate pro-inflammatory signaling and cytokine secretion, while inhibition of TPL2 decreases intestinal inflammation in vivo. However, the clinical and molecular implications of this disease-associated TPL2 variation in IBD patients have not yet been studied. Methods: We analyzed the impact of the IBD-associated TPL2 variation using clinical data of 2145 genotyped patients from the Swiss IBD Cohort Study (SIBDCS). Furthermore, we assessed the molecular consequences of the TPL2 variation in ulcerative colitis (UC) and Crohn’s disease (CD) patients by real-time PCR and multiplex ELISA of colon biopsies or serum, respectively. Results: We found that presence of the SNP rs1042058 within the TPL2 gene locus results in significantly higher numbers of CD patients suffering from peripheral arthritis. In contrast, UC patients carrying this variant feature a lower risk for intestinal surgery. On a molecular level, the presence of the rs1042058 (GG) IBD-risk polymorphism in TPL2 was associated with decreased mRNA levels of IL-10 in CD patients and decreased levels of IL-18 in the intestine of UC patients. Conclusions: Our data suggest that the presence of the IBD-associated TPL2 variation might indicate a more severe disease course in CD patients. These results reveal a potential therapeutic target and demonstrate the relevance of the IBD-associated TPL2 SNP as a predictive biomarker in IBD.

Gut microbiota appears to be involved in the pathogenesis of primary sclerosing cholangitis (PSC). The protein tyrosine phosphatase nonreceptor 2 (PTPN2) gene risk variant rs1893217 is associated with gut dysbiosis in inflammatory bowel disease (IBD), and PTPN2 was mentioned as a possible risk gene for PSC. This study assessed the microbial profile of ulcerative colitis (UC) patients with PSC and without PSC (non-PSC). Additionally, effects of the PTPN2 risk variant were assessed. In total, 216 mucosal samples from ileum, colon, and rectum were collected from 7 PSC and 42 non-PSC patients, as well as 28 control subjects (non-IBD). The microbial composition was derived from 16S rRNA sequencing data. Overall, bacterial richness was highest in PSC patients, who also had a higher relative abundance of the genus Roseburia compared to non-PSC, as well as Haemophilus, Fusobacterium, Bifidobacterium, and Actinobacillus compared to non-IBD, as well as a lower relative abundance of Bacteroides compared to non-PSC and non-IBD, respectively. After exclusion of patients with the PTPN2 risk variant, Brachyspira was higher in PSC compared to non-PSC, while, solely in colon samples, Eubacterium and Tepidimonas were higher in PSC vs. non-IBD. In conclusion, this study underlines the presence of gut mucosa-associated microbiome changes in PSC patients and rather weakens the role of PTPN2 as a PSC risk gene.

An acute sigmoid volvulus is due to the torsion of the sigmoid colon around its mesenteric axis. It mainly occurs in elderly patients and represents an abdominal emergency requiring urgent treatment. A 53-year-old male patient with severe craniocerebral injury and traumatic subarachnoidal bleeding 3 weeks prior presented on the ward with distended abdomen without abdominal pain, muscular defense, or resistances. He featured large volume diarrhea within the last few hours without signs of bleeding. A plain abdominal X-ray demonstrated a coffee bean sign indicating a sigmoid volvulus. A consequent CT scan of the abdomen revealed a deep outlet obstruction with massively dilated, elongated and twisted loop of the sigmoid colon and no signs of perforation. We performed emergency colonoscopy under the assumption of an acute sigmoid volvulus. After careful insertion of the endoscope completely refraining from insufflation of air or CO2, endoscopic reposition of the sigma could be achieved and a colonic drainage was placed over an inserted guide wire up to the proximal transverse colon. No relapse occurred and a diagnostic colonoscopy after 4 weeks revealed no tumor or polyps. Our report describes a classic case of acute sigmoid volvulus and undermines the potential of colonoscopy as conservative primary treatment of choice.

Background: The knowledge about risk factors for the onset of uveitis manifestations in patients with inflammatory bowel disease (IBD) is still limited. Here, we aimed to provide an overview of the clinical factors associated with the onset of uveitis in the Swiss IBD Cohort Study (SIBDCS). Methods: We included epidemiological and clinical data from 1840 patients with Crohn’s disease (CD) and 1426 patients with ulcerative colitis (UC) followed up in the SIBDCS between 2006 and 2018. Associations between disease characteristics and uveitis were assessed in univariate and multivariate analyses. Results: Overall, we identified 285 patients with uveitis. Uveitis was more frequent in patients with CD (11.1%; 205 of 1635) than UC (5.6%; 80 of 1346; odds ratio 2.11, p

Murine models are valuable tools to study the role of gut microbiota in health or disease. However, murine and human microbiota differ in species composition, so further investigation of the murine gut microbiota is important to gain a better mechanistic understanding. Continuous in vitro fermentation models are powerful tools to investigate microbe-microbe interactions while circumventing animal testing and host confounding factors, but are lacking for murine gut microbiota. We therefore developed a novel continuous fermentation model based on the PolyFermS platform adapted to the murine caecum and inoculated with immobilized caecal microbiota. We followed a stepwise model development approach by adjusting parameters [pH, retention time (RT), growth medium] to reach fermentation metabolite profiles and marker bacterial levels similar to the inoculum. The final model had a stable and inoculum-alike fermentation profile during continuous operation. A lower pH during startup and continuous operation stimulated bacterial fermentation (115 mM short-chain fatty acids at pH 7 to 159 mM at pH 6.5). Adjustments to nutritive medium, a decreased pH and increased RT helped control the in vitro Enterobacteriaceae levels, which often bloom in fermentation models, to 6.6 log gene copies/mL in final model. In parallel, the Lactobacillus, Lachnospiraceae, and Ruminococcaceae levels were better maintained in vitro with concentrations of 8.5 log gene copies/mL, 8.8 log gene copies/mL and 7.5 log gene copies/mL, respectively, in the final model. An independent repetition with final model parameters showed reproducible results in maintaining the inoculum fermentation metabolite profile and its marker bacterial levels. Microbiota community analysis of the final model showed a decreased bacterial diversity and compositional differences compared to caecal inoculum microbiota. Most of the caecal bacterial families were represented in vitro, but taxa of the Muribaculaceae family were not maintained. Functional metagenomics prediction showed conserved metabolic and functional KEGG pathways between in vitro and caecal inoculum microbiota. To conclude, we showed that a rational and stepwise approach allowed us to model in vitro the murine caecal microbiota and functions. Our model is a first step to develop murine microbiota model systems and offers the potential to study microbiota functionality and structure ex vivo.

The aberrant regulation of the epithelial barrier integrity is involved in many diseases of the digestive tract, including inflammatory bowel diseases and colorectal cancer. Intestinal epithelial cell organoid cultures provide new perspectives for analyses of the intestinal barrier in vitro. However, established methods of barrier function analyses from two dimensional cultures have to be adjusted to the analysis of three dimensional organoid structures. Here we describe the methodology for analysis of epithelial barrier function and molecular regulation in intestinal organoids. Barrier responses to interferon-γ of intestinal organoids with and without epithelial cell-specific deletion of the interferon-γ-receptor 2 gene were used as a model system. The established method allowed monitoring of the kinetics of interferon-γ-induced permeability changes in living organoids. Proteolytic degradation and altered localization of the tight junction proteins claudin-2, −7, and − 15 was detected using confocal spinning disc microscopy with 3D reconstruction. Hessian analysis was used for quantification of re-localization of claudins. In summary, we provide a novel methodologic approach for quantitative analyses of intestinal epithelial barrier functions in the 3D organoid model. Keywords: Inflammatory bowel disease, Interferon-gamma, Intestinal organoids, 3D imaging, Permeability, Tight junction

BACKGROUND/AIMS:Extraintestinal cutaneous manifestations of IBD represent a severe disease complication and an early and accurate treatment might positively influence the disease course. Using the patient collective of the Swiss IBD Cohort Study (SIBDCS), we analysed epidemiological as well as clinical factors being associated with the onset of pyoderma gangrenosum, erythema nodosum and aphthous ulcers in IBD patients. METHODS:We included 3266 SIBDCs patients, 1840 with Crohn's disease (CD) and 1426 with ulcerative colitis (UC) or IBD unclassified (IBDU) and analysed the association of cutaneous manifestations with age, age at diagnosis time, type of disease, gender, family history, HLA-allotype, smoking, intestinal disease activity, therapy and other extraintestinal manifestations (EIM). RESULTS:354 CD patients and 136 UC/IBDU patients presented with skin manifestations at any time during their disease course. In both, CD and UC, female gender and younger age at IBD diagnosis were significantly associated with extraintestinal skin manifestations. For CD, we also detected a positive family history as associated factor. As an indicator of more intensive intestinal disease activity, patients with cutaneous manifestations of IBD needed more frequently therapy with antibiotics, steroids, immunomodulators and anti-TNF. Multivariate analysis revealed female gender, younger age at diagnosis and presence of other extraintestinal manifestations as factors being associated with skin EIM in IBD patients and anti-TNF as well as immunomodulatory treatment in CD patients. CONCLUSION:Our results suggest that young females with a positive family history of IBD might be at increased risk for the onset of skin manifestations and require a careful screening for such complications.

Background/aimsExtraintestinal manifestations (EIM) involving joints, skin, eyes and liver represent an important problem in the treatment of IBD patients. The aim of this study was to identify factors that are associated with the occurrence of joint EIM and therefore allow an early diagnosis and guide medical treatment.MethodsWe studied clinical and epidemiological data from 3298 patients included in the Swiss IBD Cohort Study (SIBDCS), 1860 suffered from Crohn's disease (CD) and 1438 from ulcerative colitis or IBD unclassified (UC/IBDU).ResultsWe found female gender as well as a longer disease duration and activity (specified as CDAI or MTWAI, respectively) to be related to the appearance of arthritis/arthralgia, but also sacroiliitis/ankylosing spondylitis in IBD patients. IBD patients with arthritis/arthralgia or sacroiliitis/ankylosing spondylitis were more often treated with anti-TNF and patients with arthritis/arthralgia underwent more often IBD-related surgeries. We revealed that eye or skin EIM were more frequent in patients with arthritis/arthralgia or sacroiliitis/ankylosing spondylitis. In multivariate analysis, we confirmed female gender, longer disease duration, IBD-related surgery, presence of other EIM and treatment with anti-TNF to be independent risk factors for the onset of arthritis/arthralgia in CD and UC/IBDU patients.ConclusionIn this study, we demonstrated that markers for a more severe disease course were associated with the onset of joint EIM in IBD patients. Our data suggest that in particular females under anti-TNF treatment and patients suffering from non-joint and/or IBD-related surgery should be close and carefully monitored for presence of arthritis or sacroiliitis/ankylosing spondylitis.

BackgroundExtraintestinal manifestations (EIM) contribute significantly to the burden of disease in inflammatory bowel disease (IBD). Pain is a leading symptom in IBD and could be seen as an EIM itself. Treatment of IBD associated pain is challenging and insufficiently studied. A better knowledge on the association of pain and IBD specific treatment is warranted to improve the management of IBD patients.MethodsAll patients of the Swiss IBD Cohort Study (SIBDCS) (n = 2152) received a questionnaire regarding pain localization, pain character, and the use of IBD specific medication.Results1263 completed questionnaires were received. Twenty-one out of 184 patients (10%) receiving anti-TNF treatment compared to 142 out of 678 patients (21%) not receiving anti-TNF medication reported elbow pain (p = 0.002) while 28 out of 198 patients (14%) receiving steroid treatment significantly more often reported elbow pain compared to 59 from 696 patients (8%) not receiving steroids (p = 0.021). Furthermore, we found significantly more female patients under anti-TNF treatment to report knee/ lower leg pain and ankle/ foot pain compared to their male counterparts (36% vs. 20% and 22% vs. 10%, respectively, p = 0.015 for both comparisons). The frequency of knee, lower leg, ankle and foot pain was especially low in male patients under anti-TNF treatment, indicating a high benefit of male patients from anti-TNF therapy regarding EIM.ConclusionsThe frequency of elbow pain was lower in IBD patients treated with anti-TNF but higher in patients treated with steroids.

Hepatitis C is frequently accompanied by immune-related extrahepatic manifestations affecting the skin, kidneys, central and peripheral nervous system and exocrine glands. We present the case of a 40-year-old man with left-sided ptosis, exophthalmos and headache. MRI demonstrated left-sided orbital pseudotumor with lacrimal and retro-orbital contrast enhancement extending to the cavernous sinus and the vestibulocochlear nerve. Immunological tests of serum and cerebrospinal fluid identified hepatitis C virus (HCV) as a potential causative agent but did not indicate any additional infectious, malignant or immunological disorder. Hepatological evaluation revealed no signs of advanced liver disease. After initial spontaneous improvement, the patient subsequently developed vestibulocochlear failure with gait disorder, tinnitus and transient left-parietal sensory loss. Lacrimal biopsy demonstrated lymphocytic infiltrate, prompting steroid treatment. After initial improvement, steroids could not be tapered below 40 mg daily for several months due to recurrent symptoms. Twelve months after the initial presentation, the patient’s chronic HCV infection was successfully treated with sofosbuvir, simeprevir and ribavirin and he remains now free of symptoms without steroids. In patients with chronic hepatitis C, lymphocytic infiltrate of the salivary and lacrimal glands is a frequent phenomenon. However, the extent of the lymphocytic infiltrate beyond the lacrimal gland to the tip of the orbit, cavernous sinus and vestibulocochlear nerve as in our patient is highly unusual. For all symptomatic extrahepatic manifestations of hepatitis C infection, treatment of HCV as the underlying immune stimulus is recommended, and it helped to control the symptoms in our patient. In addition, long-term follow-up for recurrent lymphocyte infiltrate and development of lymphoma is warranted.

The pathogenesis of Crohn’s disease-associated fibrostenosis and fistulas imply the epithelial-to-mesenchymal transition (EMT) process. As succinate and its receptor (SUCNR1) are involved in intestinal inflammation and fibrosis, we investigated their relevance in EMT and Crohn’s disease (CD) fistulas. Succinate levels and SUCNR1-expression were analyzed in intestinal resections from non-Inflammatory Bowel Disease (non-IBD) subjects and CD patients with stenosing-B2 or penetrating-B3 complications and in a murine heterotopic-transplant model of intestinal fibrosis. EMT, as increased expression of Snail1, Snail2 and vimentin and reduction in E-cadherin, was analyzed in tissues and succinate-treated HT29 cells. The role played by SUCNR1 was studied by silencing its gene. Succinate levels and SUCNR1 expression are increased in B3-CD patients and correlate with EMT markers. SUCNR1 is detected in transitional cells lining the fistula tract and in surrounding mesenchymal cells. Grafts from wild type (WT) mice present increased succinate levels, SUCNR1 up-regulation and EMT activation, effects not observed in SUCNR1−/− tissues. SUCNR1 activation induces the expression of Wnt ligands, activates WNT signaling and induces a WNT-mediated EMT in HT29 cells. In conclusion, succinate and its receptor are up-regulated around CD-fistulas and activate Wnt signaling and EMT in intestinal epithelial cells. These results point to SUCNR1 as a novel pharmacological target for fistula prevention.

Disruption of epithelial junctional complex (EJC), especially tight junctions (TJ), resulting in increased intestinal permeability, is supposed to activate the enhanced immune response to gluten and to induce the development of celiac disease (CD). This study is aimed to present the role of EJC in CD pathogenesis. To analyze differentially expressed genes the next-generation mRNA sequencing data from CD326+ epithelial cells isolated from non-celiac and celiac patients were involved. Ultrastructural studies with morphometry of EJC were done in potential CD, newly recognized active CD, and non-celiac controls. The transcriptional analysis suggested disturbances of epithelium and the most significant gene ontology enriched terms in epithelial cells from CD patients related to the plasma membrane, extracellular exome, extracellular region, and extracellular space. Ultrastructural analyses showed significantly tighter TJ, anomalies in desmosomes, dilatations of intercellular space, and shorter microvilli in potential and active CD compared to controls. Enterocytes of fetal-like type and significantly wider adherence junctions were observed only in active CD. In conclusion, the results do not support the hypothesis that an increased passage of gluten peptides by unsealing TJ precedes CD development. However, increased intestinal permeability due to abnormality of epithelium might play a role in CD onset.

The relevance of genetic and epigenetic alterations in the pathogenesis of inflammatory bowel disease (IBD) is still poorly understood. So far, 240 risk gene loci have been associated with IBD. They are mainly involved in regulating innate and adaptive immunity, as well as maintaining intestinal epithelial barrier function. However, the functional consequences of the identified genetic polymorphisms for IBD pathogenesis in vivo are often unknown. Even less is known about the role for epigenetic modifications in IBD pathogenesis. Though a number of epigenetic events seem to be causatively involved IBD pathogenesis, our knowledge about the functional relevance of those epigenetic modifications is scanty. This opens up a broad research field that generates novel insights into the pathophysiology of intestinal and chronic inflammatory disease. Patterns of DNA methylation and histone modifications might serve not only as biomarkers of disease activity or disease course, but also as new targets in therapeutic interventions in IBD patients.

We have recently demonstrated that macrophage-specific loss of Protein tyrosine phosphatase non-receptor type 2 (PTPN2) promotes inflammasome activation, resulting in protection from colorectal cancer. Here we place these findings in context with the role of inflammasomes in colorectal carcinoma, and with a recent study indicating that PTPN2-silencing promotes anti-cancer immunotherapy.

Due to its particulate material, mono-sodium urate (MSU) crystals are potent activators of the NOD-like receptor NLRP3. Upon activation, NLRP3 induces the formation of inflammasome complexes, which lead to the production and release of mature IL-1β. Bioactive IL-1β is a potent activator of innate immune responses and promotes recruitment of inflammatory cells, including neutrophils from the blood into damaged/inflamed tissues. This protocol describes a method to study in vivo inflammasome activation via intraperitoneal injection of MSU crystals. MSU-injection results in a drastic increase of intraperitoneal IL-1β levels, promoting neutrophil infiltration. Early-stage neutrophil numbers correlate with the amount of released IL-1β and can be used as a read-out for the extent of in vivo inflammasome activation. In addition, this protocol might also be used as a sterile peritonitis model, to investigate mechanisms of neutrophil recruitment to the peritoneum, or as a means to obtain large numbers of in vivo activated neutrophils.

The exact pathophysiology of inflammatory bowel disease (IBD) is still unknown. However, over the years important insights allowed the development of novel therapeutic approaches that are at the threshold of introduction into clinical practice, or at least in clinical trials. After being first described by Burrill B. Crohn, Crohn’s disease, one of the two major forms of IBD, was perceived as an infectious disease. When the concept of autoimmune diseases was formulated, Crohn’s disease and ulcerative colitis were thought to be members of this disease group. T cells certainly contribute to the chronification of the intestinal inflammation and targeting T cell migration has been introduced some years ago as a successful therapeutic approach in IBD. Despite the development of successful therapy based on this pathophysiological concept, IBD is no longer seen as a typical autoimmune disease. After the millennium, genome wide association studies on genetic variants and risk factors in these polygenetic diseases have told us a lot about pathogenetic pathways. However, genetic susceptibility explains only up to one third of the cases. Environmental factors also must play a role. Those environmental factors may “transfer” their disease-promoting potential into pathophysiological pathways with the intestinal microbiota as mediator. Hence, the intestinal microbiota has gained much attention as an important factor in disease development. Microbial factors, as well as other direct environmental influences, have been shown to affect epigenetic signatures, intestinal epithelial cells and the innate immune system, providing another important concept on how these diseases originate and can cause repeated flares at the same gut segments even after years of remission and after intermediate complete mucosal healing. Current pathophysiological concepts of IBD not only help us to better understand these diseases and develop new therapies. They also illustrate the evolution of basic scientific concepts over time and that sometimes partially or even largely abandoned concepts persistently influence out current thinking/clinical practice.

Background: Zinc deficiency (ZD) in Crohn’s disease (CD) is considered a frequent finding and may exacerbate CD activity. ZD is associated with depression in non-CD patients. We aimed to assess the prevalence of ZD in CD patients in clinical remission, its association with mood disturbances and to analyze a potential impact on future disease course. Methods: Zinc levels from CD patients in clinical remission at baseline and an uncomplicated disease course within the next 3 years ( n = 47) were compared with those from patients developing complications ( n = 50). Baseline symptoms of depression and anxiety were measured with the Hospital Anxiety and Depression scale. Results: Mean zinc level in the 97 patients (40.4 ± 15.7 years, 44.3% males) was 18.0 ± 4.7 μmol/l. While no ZD (

BACKGROUND AND AIMS:Lactulose is a common food ingredient and widely used as a treatment for constipation or hepatic encephalopathy and a substrate for hydrogen breath tests. Lactulose is fermented by the colon microbiota resulting in the production of hydrogen (H2). H2 is a substrate for enteropathogens including Salmonella Typhimurium (S. Typhimurium) and increased H2 production upon lactulose ingestion might favor the growth of H2-consuming enteropathogens. We aimed to analyze effects of single-dose lactulose ingestion on the growth of intrinsic Escherichia coli (E. coli), which can be efficiently quantified by plating and which share most metabolic requirements with S. Typhimurium. METHODS:32 healthy volunteers (18 females, 14 males) were recruited. Participants were randomized for single-dose ingestion of 50 g lactulose or 50 g sucrose (controls). After ingestion, H2 in expiratory air and symptoms were recorded. Stool samples were acquired at days -1, 1 and 14. We analyzed 16S microbiota composition and abundance and characteristics of E. coli isolates. RESULTS:Lactulose ingestion resulted in diarrhea in 14/17 individuals. In 14/17 individuals, H2-levels in expiratory air increased by ≥20 ppm within 3 hours after lactulose challenge. H2-levels correlated with the number of defecations within 6 hours. E. coli was detectable in feces of all subjects (2 x 10(2)-10(9) CFU/g). However, the number of E. coli colony forming units (CFU) on selective media did not differ between any time point before or after challenge with sucrose or lactulose. The microbiota composition also remained stable upon lactulose exposure. CONCLUSION:Ingestion of a single dose of 50 g lactulose does not significantly alter E. coli density in stool samples of healthy volunteers. 50 g lactulose therefore seems unlikely to sufficiently alter growth conditions in the intestine for a significant predisposition to infection with H2-consuming enteropathogens such as S. Typhimurium (www.clinicaltrials.gov NCT02397512).

BACKGROUND:Genetic risk factors, intestinal microbiota and a dysregulated immune system contribute to the pathogenesis of inflammatory bowel disease (IBD). We have previously demonstrated that dysfunction of protein tyrosine phosphatase non-receptor type 2 (PTPN2) and PTPN22 contributes to alterations of intestinal microbiota and the onset of chronic intestinal inflammation in vivo. Here, we investigated the influence of PTPN2 and PTPN22 gene variants on intestinal microbiota composition in IBD patients. METHODS:Bacterial DNA from mucosa-associated samples of 75 CD and 57 UC patients were sequenced using 16S rRNA sequencing approach. Microbial analysis, including alpha diversity, beta diversity and taxonomical analysis by comparing to PTPN2 (rs1893217) and PTPN22 (rs2476601) genotypes was performed in QIIME, the phyloseq R package and MaAsLin pipeline. RESULTS:In PTPN2 variant UC patients, we detected an increase in relative abundance of unassigned genera from Clostridiales and Lachnospiraceae families and reduction of Roseburia when compared to PTPN2 wild-type (WT) patients. Ruminoccocus was increased in PTPN22 variant UC patients. In CD patients with severe disease course, Faecalibacterium, Bilophila, Coprococcus, unclassified Erysipelotrichaeceae, unassigned genera from Clostridiales and Ruminococcaceae families were reduced and Bacteroides were increased in PTPN2 WT carriers, while Faecalibacterium, Bilophila, Coprococcus, and Erysipelotrichaeceae were reduced in PTPN22 WT patients when compared to patients with mild disease. In UC patients with severe disease, relative abundance of Lachnobacterium was reduced in PTPN2 and PTPN22 WT patients, Dorea was increased in samples from PTPN22 WT carriers and an unassigned genus from Ruminococcaceae gen. was increased in patients with PTPN2 variant genotype. CONCLUSIONS:We identified that IBD-associated genetic risk variants, disease severity and the interaction of these factors are related to significant alterations in intestinal microbiota composition of IBD patients.

Gp96 is an endoplasmic reticulum chaperone for multiple protein substrates. Its lack in intestinal macrophages of Crohn's disease (CD) patients is correlated with loss of tolerance against the host gut flora. Gp96 has been stablished to be an essential chaperone for Toll-like receptors (TLRs). We studied the impact of gp96-knockdown on TLR-function in macrophages. TLR2 and TLR4 expression was only decreased but not abolished when gp96 was knocked-down in cell lines, whereas in a monocyte/macrophage specific knock-out mouse model (LysMCre) TLR4 was abolished, while TLR2 was still present. Lipopolysaccharide (LPS)-induced NF-κB activation was still observed in the absence of gp96, and gp96-deficient macrophages were able to up-regulate surface TLR4 upon LPS treatment, suggesting that there is another chaperone involved in the folding of TLR4 upon stress responses. Moreover, LPS-dependent pro-inflammatory cytokines were still expressed, although to a lesser extent in the absence of gp96, which reinforces the fact that gp96 is involved in regulating signaling cascades downstream of TLR4 are impaired upon loss of gp96. In addition, we have also found a reduced phosphorylation of ERK and p38 kinases and an impaired response upon CSF1R activation in gp96 deficient macrophages. Our findings indicate that the loss of gp96 not only impairs TLR4 signaling, but is also associated with a diminished phosphorylation of ERK and mitogen-activated stress kinases resulting in an impaired signalling through several receptors, including CSF1R.

[This corrects the article DOI: 10.1371/journal.pone.0147682.].

Gallstones and kidney stones are known complications of inflammatory bowel diseases (IBD). Risk factors have been insufficiently studied and explanatory studies date back up to 30 years. It remains unclear, whether improved treatment options also influenced risk factors for these complications.Identifying risk factors for gallstones and kidney stones in IBD patients.Using data from the Swiss Inflammatory Bowel Disease Cohort Study we assessed associations of diseases characteristics with gallstones and kidney stones in univariate and multivariate logistic regression analyses.Out of 2323 IBD patients, 104 (7.8%) Crohn's disease (CD) and 38 (3.8%) ulcerative colitis (UC) patients were diagnosed with gallstones. Significant risk factors for gallstones were diagnosis of CD, age at diagnosis, disease activity and duration, NSAID intake, extra-intestinal manifestations and intestinal surgery. Kidney stones were described in 61 (4.6%) CD and 30 (3.0%) UC patients. Male gender, disease activity, intestinal surgery, NSAID usage and reduced physical activity were significant risk factors. Hospitalization was associated with gallstones and kidney stones. The presence of gallstones increased the risk for kidney stones (OR 4.87, p