Predicting complications in pediatric Crohn's disease patients followed in CEDATA-GPGE registry.

Background: Complications of Crohn's disease (CD) often impair patients' quality of life. It is necessary to predict and prevent these complications (surgery, stricturing [B2]/penetrating [B3] disease behavior, perianal disease, growth retardation and hospitalization). Our study investigated previously suggested and additional predictors by analyzing data of the CEDATA-GPGE registry. Methods: Pediatric patients (< 18 years) diagnosed with CD with follow up data in the registry were included in the study. Potential risk factors for the selected complications were evaluated by performing Kaplan-Meier survival curves and cox regression models. Results: For the complication surgery, the potential risk factors older age, B3 disease, severe perianal disease and initial therapy with corticosteroids at the time of diagnosis were identified. Older age, initial therapy with corticosteroids, low weight-for-age, anemia and emesis predict B2 disease. Low weight-for-age and severe perianal disease were risk factors for B3 disease. Low weight-for-age, growth retardation, older age, nutritional therapy, and extraintestinal manifestations (EIM) of the skin were identified as risk factors for growth retardation during the disease course. High disease activity and treatment with biologicals were predictors for hospitalization. As risk factors for perianal disease, the factors male sex, corticosteroids, B3 disease, a positive family history and EIM of liver and skin were identified. Conclusion: We confirmed previously suggested predictors of CD course and identified new ones in one of the largest registries of pediatric CD patients. This may help to better stratify patients' according to their individual risk profile and choose appropriate treatment strategies.

New Insights on CD8+ T Cells in Inflammatory Bowel Disease and Therapeutic Approaches.

CD8+ T cells are involved in the pathogenesis of inflammatory bowel disease (IBD), a complex multifactorial chronic disease. Here, we present an overview of the current research with the controversial findings of CD8+ T cell subsets and discuss some possible perspectives on their therapeutic value in IBD. Studies on the role of CD8+ T cells in IBD have contradictory outcomes, which might be related to the heterogeneity of the cells. Recent data suggest that cytotoxic CD8+ T cells (Tc1) and interleukin (IL) 17-producing CD8+ (Tc17) cells contribute to the pathogenesis of IBD. Moreover, subsets of regulatory CD8+ T cells are abundant at sites of inflammation and can exhibit pro-inflammatory features. Some subsets of tissue resident memory CD8+ T cells (Trm) might be immunosuppressant, whereas others might be pro-inflammatory. Lastly, exhausted T cells might indicate a positive outcome for patients. The function and plasticity of different subsets of CD8+ T cells in health and IBD remain to be further investigated in a challenging field due to the limited availability of mucosal samples and adequate controls.

Risk Factors of Growth Retardation and Developmental Deficits in Very Preterm Infants in a German Tertiary Neonatal Unit.

Over the last two decades, improvements in perinatology have led to increased survival rates of preterm infants. A large number of studies and meta-analyses have investigated of preterm infants and/or the influence of developmental care. However, the combined influence of the most frequent risk factors and developmental care on the long-term somatic, motor, and cognitive outcome of preterm infants remains unclear. This retrospective, single-center cohort study includes 256 children treated in a tertiary neonatal intensive care unit in Rostock, Germany, between 2008 and 2013. Follow-up examinations (somatic, psychomotor, and mental development) were performed at (corrected) 24 months using Bayley Scales of Infant Development II (BSID-II). Developmental care was carried out according to the legal framework and national guidelines (physiotherapy and/or early education). Bronchopulmonary dysplasia (BPD) and an exclusive formula feeding showed a 2.8-4.6-fold higher risk (95% Confidence Interval: Mental Developmental Index 1.73-7.58; Psychomotor Developmental Index 1.44-14.54; body length 1.20-6.41) for developmental deficits (mental and psychomotor developmental index; body length). Developmental care after discharge according to national guidelines did not prevent this. Since this is a retrospective pilot study, no recommendations can be made based on this analysis. Therefore, future research should evaluate whether standard developmental care should be extended by tailored measures depending on individual risk factors.

Predicting Outcomes in Pediatric Crohn's Disease for Management Optimization: Systematic Review and Consensus Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.

BACKGROUND & AIMS: A better understanding of prognostic factors within the heterogeneous spectrum of pediatric Crohn's disease (CD) should improve patient management and reduce complications. We aimed to identify evidence-based predictors of outcomes with the goal of optimizing individual patient management. METHODS: A survey of 202 experts in pediatric CD identified and prioritized adverse outcomes to be avoided. A systematic review of the literature with meta-analysis, when possible, was performed to identify clinical studies that investigated predictors of these outcomes. Multiple national and international face-to-face meetings were held to draft consensus statements based on the published evidence. RESULTS: Consensus was reached on 27 statements regarding prognostic factors for surgery, complications, chronically active pediatric CD, and hospitalization. Prognostic factors for surgery included CD diagnosis during adolescence, growth impairment, NOD2/CARD15 polymorphisms, disease behavior, and positive anti-Saccharomyces cerevisiae antibody status. Isolated colonic disease was associated with fewer surgeries. Older age at presentation, small bowel disease, serology (anti-Saccharomyces cerevisiae antibody, antiflagellin, and OmpC), NOD2/CARD15 polymorphisms, perianal disease, and ethnicity were risk factors for penetrating (B3) and/or stenotic disease (B2). Male sex, young age at onset, small bowel disease, more active disease, and diagnostic delay may be associated with growth impairment. Malnutrition and higher disease activity were associated with reduced bone density. CONCLUSIONS: These evidence-based consensus statements offer insight into predictors of poor outcomes in pediatric CD and are valuable when developing treatment algorithms and planning future studies. Targeted longitudinal studies are needed to further characterize prognostic factors in pediatric CD and to evaluate the impact of treatment algorithms tailored to individual patient risk.

Predicting Outcomes in Pediatric Ulcerative Colitis for Management Optimization: Systematic Review and Consensus Statements From the Pediatric Inflammatory Bowel Disease-Ahead Program.

BACKGROUND & AIMS: A better understanding of prognostic factors in ulcerative colitis (UC) could improve patient management and reduce complications. We aimed to identify evidence-based predictors for outcomes in pediatric UC, which may be used to optimize treatment algorithms. METHODS: Potential outcomes worthy of prediction in UC were determined by surveying 202 experts in pediatric UC. A systematic review of the literature, with selected meta-analysis, was performed to identify studies that investigated predictors for these outcomes. Multiple national and international meetings were held to reach consensus on evidence-based statements. RESULTS: Consensus was reached on 31 statements regarding predictors of colectomy, acute severe colitis (ASC), chronically active pediatric UC, cancer and mortality. At diagnosis, disease extent (6 studies, N = 627; P = .035), Pediatric Ulcerative Colitis Activity Index score (4 studies, n = 318; P < .001), hemoglobin, hematocrit, and albumin may predict colectomy. In addition, family history of UC (2 studies, n = 557; P = .0004), extraintestinal manifestations (4 studies, n = 526; P = .048), and disease extension over time may predict colectomy, whereas primary sclerosing cholangitis (PSC) may be protective. Acute severe colitis may be predicted by disease severity at onset and hypoalbuminemia. Higher Pediatric Ulcerative Colitis Activity Index score and C-reactive protein on days 3 and 5 of hospital admission predict failure of intravenous steroids. Risk factors for malignancy included concomitant diagnosis of primary sclerosing cholangitis, longstanding colitis (>10 years), male sex, and younger age at diagnosis. CONCLUSIONS: These evidence-based consensus statements offer predictions to be considered for a personalized medicine approach in treating pediatric UC.

Large Duodenal Hematoma Causing an Ileus after an Endoscopic Duodenal Biopsy in a 6-Year-Old Child: A Case Report.

Intramural duodenal hematoma (IDH) in children is a rare complication after esophagogastroduodenoscopy. It is commonly described in patients with additional disorders or risk factors, such as coagulopathy. We present a case of a previously healthy 6-year-old boy with a large obstructing intramural duodenal hematoma and concomitant pancreatitis after an elective esophagogastroduodenoscopy. The patient presented with typical symptoms of an IDH, such as abdominal pain and distension, nausea and vomiting. IDH was diagnosed using ultrasound and magnetic resonance imaging examination. Conservative management with gastric decompression using a nasogastric feeding tube, bowel rest, total parenteral nutrition and analgesia was performed. After three weeks, the patient was discharged from the hospital without any complaints. Interventional management of IDH in pediatric patients with a lack of response to conservative therapy or complicating IDH should be discussed in an interdisciplinary team.

Limitations and Off-Target Effects of Tryptophan-Related IDO Inhibitors in Cancer Treatment.

Immunooncology is still a growing area in cancer therapy. Drugs within this therapeutic approach do not directly target/attack the tumor but interfere with immune checkpoints and target or reprogram key metabolic pathways critical for anti-cancer immune defense. Indolamine 2,3-dioxygenase 1 (IDO1) and the tryptophan (TRP)-kynurenine pathway were identified as critical mechanisms in cancer immune escape and their inhibition as an approach with promising therapeutic potential. Particularly, a multitude of IDO1 inhibiting tryptophan analogs are widely applied in several clinical trials. However, this therapy results in a variety of implications for the patient's physiology. This is not only due to the inhibition of an enzyme important in almost every organ and tissue in the body but also because of the general nature of the inhibitor as an analog of a proteinogenic amino acid as well as the initiation of cellular detoxification known to affect inflammatory pathways. In this review we provide a deeper insight into the physiological consequences of an IDO1 inhibiting therapy based on TRP related molecules. We discuss potential side and off-target effects that contribute to the interpretation of unexpected positive as well as negative results of ongoing or discontinued clinical studies while we also highlight the potential of these inhibitors independent of the IDO1 signaling pathway.

Long-term implications of structured transition of adolescents with inflammatory bowel disease into adult health care: a retrospective study.

BACKGROUND: We aimed to evaluate the long-term clinical and socioeconomic outcome of structured transition care in adolescents with inflammatory bowel disease (IBD). METHODS: We compared the clinical long-term course of 24 patients with and 11 patients without structured transition care within 24 months before and 24 months after transfer from paediatric to adult health care. Socio-economic parameters and quality of life were assessed by IBD Questionnaire (IBDQ-32) and additional items. Treatment costs were calculated for medication, surgery and hospitalisation. RESULTS: The percentage of transfer group patients with an IBD-related intestinal complication was higher compared to the transition group (64% vs. 21%, p = 0.022). We also found a tendency towards a higher number of IBD-related surgery in the transfer group compared to the transition group (46% vs. 13%, p = 0.077). Transfer group patients received higher mean cumulated doses of radiation compared with the transition group (4.2 ± 5.3 mSv vs. 0.01 ± 0.01 mSv, p = 0.036). Delayed puberty was only noted in the transfer group (27%, p = 0.025). Mean expenditures for surgeries and hospitalisation tended to be lower in the transition group compared to transfer group patients (744 ± 630€ vs. 2,691 ± 4,150€, p = 0.050). Sexual life satisfaction was significantly higher (p = 0.023) and rates of loose bowel movements tended to be lower (p = 0.053) in the transition group. CONCLUSIONS: Structured transition of adolescents with IBD from paediatric into adult health care can lead to important clinical and economic benefits.

Somatic development at birth as influenced by maternal characteristics - an analysis of the German Perinatal Survey.

We investigated the effects of maternal age, body weight, body height, weight gain during pregnancy, smoking during pregnancy, previous live births and being a single mother on somatic development at birth. We analysed data from the German Perinatal Survey for the years 1998-2000 from eight German federal states. We had available data on 508,926 singleton pregnancies and neonates in total; for 508,893 of which we could classify the neonates as small, appropriate or large for gestational age (SGA, AGA or LGA) based on the 10th and 90th birth weight percentiles. Multivariable regression analyses found statistically significant effects of a clinically relevant magnitude for smoking during pregnancy [odds ratio (OR) 2.9 for SGA births for women smoking >10 cigarettes per day], maternal height (OR 1.4 for SGA births for women <162 cm; OR 1.4 for LGA births for women >172 cm), maternal weight (OR 1.5 for SGA births for women <59 kg; OR 1.9 for LGA births for women >69 kg), weight gain during pregnancy (OR 1.9 for SGA births for women with a weight gain <8 kg; OR 2.0 for LGA births for women with a weight gain >18 kg) and previous live births (OR 2.1 for LGA births for women with one or more previous live births). Maternal age and being a single mother also had significant effects but their magnitude was small. Our analysis confirms the clinically relevant effects of smoking, maternal anthropometric measures and weight gain during pregnancy on neonatal somatic development.

Inflammatory Bowel Disease in Childhood and Adolescence.

BACKGROUND: The incidence of inflammatory bowel disease (IBD) in childhood and adolescence is 5-11 cases per 100 000 persons per year, corresponding to a new diagnosis of IBD in 800-1470 patients in Germany each year. METHODS: This review is based on pertinent publications retrieved by a selective search in PubMed, including guidelines from Germany and abroad. RESULTS: Children and adolescents with IBD often have extensive involvement and an aggressive course of disease. Nonetheless, infliximab and adalimumab are the only biological agents that have been approved for this group of patients. In Crohn's disease, exclusive enteral nutrition is the treatment of first choice for inducing a remission. Patients with (peri-)anal fistulae are treated primarily with infliximab. Corticosteroids and aminosalicylates should be used with caution. In contrast, children and adolescents with ulcerative colitis are treated with either aminosalicylates or prednisolone to induce a remission. As a rule, maintenance pharmacotherapy with thiopurines in Crohn's disease and severe ulcerative colitis, or with aminosalicylates in mild to moderate ulcerative colitis, is indicated for several years, at least until the end of puberty. Patients with refractory disease courses are treated with methylprednisolone, anti-TNF-α-antibodies, and/or calcineurin inhibitors. The spectrum of surgical interventions is the same as for adults. Specific aspects of the treatment of children and adolescents with IBD include adverse drug effects, the areas of nutrition, growth, and development, and the structured transition to adult medicine. CONCLUSION: Children and adolescents with IBD or suspected IBD should be cared for by pediatric gastroenterologists in a center where such care is provided. Individualized treatment with multidisciplinary, family-oriented longterm care is particularly important. Drug trials in children and adolescents are needed so that the off-label use of drugs to patients in this age group can be reduced.

Protease-activated Receptor 1 Plays a Proinflammatory Role in Colitis by Promoting Th17-related Immunity.

BACKGROUND: Proteolytic cleavage of protease-activated receptor 1 (PAR1) can result in potent downstream regulatory effects on inflammation. Although PAR1 is expressed throughout the gastrointestinal tract and activating proteases are increased in inflammatory bowel disease, the effect of PAR1 activation on colitis remains poorly understood, and has not previously been studied in pediatric disease. METHODS: Expression of PAR1 and inflammatory cytokines in colonic biopsies from pediatric patients with Crohn's disease exhibiting active moderate to severe colitis was measured by quantitative PCR. The functional relevance of these clinical data was further studied in a mouse model of Citrobacter rodentium-induced colitis. RESULTS: PAR1 expression was significantly upregulated in the inflamed colons of pediatric patients with Crohn's disease, with expression levels directly correlating to disease severity. In patients with severe colitis, PAR1 expression uniquely correlated with Th17-related (IL17A, IL22, and IL23A) cytokines. Infection of PAR1-deficient (PAR1) and wildtype mice with colitogenic C. rodentium revealed that disease severity and colonic pathology were strongly attenuated in mice lacking PAR1. Furthermore, Th17-type immune response was completely abolished in the colons of infected PAR1 but not wildtype mice. Finally, PAR1 was shown to be essential for secretion of the Th17-driving cytokine IL-23 by C. rodentium-stimulated macrophages. CONCLUSIONS: This study demonstrates a strong link between PAR1 expression, Th17-type immunity, and disease severity in both pediatric patients with Crohn's disease and C. rodentium-induced colitis in mice. The data presented suggest PAR1 exerts a proinflammatory role in colitis in both humans and mice by promoting a Th17-type immune response, potentially by supporting the production of IL-23.

Activation-dependent cell death of human monocytes is a novel mechanism of fine-tuning inflammation and autoimmunity.

In patients with juvenile idiopathic arthritis (JIA), increased release of IFN-γ and GM-CSF in cells infiltrating synovial tissue can be a potent driver of monocyte activation. Given the fundamental role of monocyte activation in remodeling the early phases of inflammatory responses, here we analyze the GM-CSF/IFN-γ induced activity of human monocytes in such a situation in vitro and in vivo. Monocytes from healthy donors were isolated and stimulated with GM-CSF ± IFN-γ. Monocyte activation and death were analyzed by flow cytometry, immunofluorescence microscopy, ELISA, and qPCR. T-cell GM-CSF/IFN-γ expression and monocyte function were determined in synovial fluid and peripheral blood from 15 patients with active JIA and 21 healthy controls. Simultaneous treatment with GM-CSF and IFN-γ induces cell death of monocytes. This cell death is partly cathepsin B-associated and has morphological characteristics of necrosis. Monocytes responding to costimulation with strong proinflammatory activities are consequently eliminated. Monocytes surviving this form of hyperactivation retain normal cytokine production. Cathepsin B activity is increased in monocytes isolated from synovial fluid from patients with active arthritis. Our data suggest GM-CSF/IFN-γ induced cell death of monocytes as a novel mechanism to eliminate overactivated monocytes, thereby potentially balancing inflammation and autoimmunity in JIA.

Loss of gastrokine-2 drives premalignant gastric inflammation and tumor progression.

Chronic mucosal inflammation is associated with a greater risk of gastric cancer (GC) and, therefore, requires tight control by suppressive counter mechanisms. Gastrokine-2 (GKN2) belongs to a family of secreted proteins expressed within normal gastric mucosal cells. GKN2 expression is frequently lost during GC progression, suggesting an inhibitory role; however, a causal link remains unsubstantiated. Here, we developed Gkn2 knockout and transgenic overexpressing mice to investigate the functional impact of GKN2 loss in GC pathogenesis. In mouse models of GC, decreased GKN2 expression correlated with gastric pathology that paralleled human GC progression. At baseline, Gkn2 knockout mice exhibited defective gastric epithelial differentiation but not malignant progression. Conversely, Gkn2 knockout in the IL-11/STAT3-dependent gp130F/F GC model caused tumorigenesis of the proximal stomach. Additionally, gastric immunopathology was accelerated in Helicobacter pylori-infected Gkn2 knockout mice and was associated with augmented T helper cell type 1 (Th1) but not Th17 immunity. Heightened Th1 responses in Gkn2 knockout mice were linked to deregulated mucosal innate immunity and impaired myeloid-derived suppressor cell activation. Finally, transgenic overexpression of human gastrokines (GKNs) attenuated gastric tumor growth in gp130F/F mice. Together, these results reveal an antiinflammatory role for GKN2, provide in vivo evidence that links GKN2 loss to GC pathogenesis, and suggest GKN restoration as a strategy to restrain GC progression.

Altered gp130 signalling ameliorates experimental colitis via myeloid cell-specific STAT3 activation and myeloid-derived suppressor cells.

STAT3 regulates the expansion of myeloid-derived suppressor cells (MDSCs) during inflammation, infection and cancer. Hyperactivation of STAT3 in gp130(757F/F) mice is associated with protection from experimental colitis. This study determined mechanisms for this protection and compared this to mice with myeloid-specific STAT3-deficiency (LysMcre/STAT3(flox); gp130(757F/F) LysMcre/STAT3(flox)). Acute and chronic colitis was induced and colons were removed for histological, mRNA and protein analysis. Cell populations from spleen, mesenteric lymph node and colon were analyzed for different myeloid cell populations using flow cytometry. Functions of MDSCs and LPS-stimulated peritoneal macrophages were further characterized by in vitro and in vivo assays. Here we show that the resistance to experimental colitis in gp130(757F/F) mice is via myeloid-cell specific STAT3 activation, MDSC expansion and increased production of suppressive and protective cytokines.

Immunoregulatory Role of Myeloid-derived Cells in Inflammatory Bowel Disease.

As the frontiers of immunological research expand, new insights into the pathogenesis of long poorly understood diseases, such as inflammatory bowel disease (IBD), are opening up new possible avenues for treatment. Myeloid-derived cells (i.e., monocytes, macrophages, neutrophils, and dendritic cells), long believed to be effector cells driving the initiation of inflammation, have been increasingly shown to have immunoregulatory effects previously underappreciated. Dysfunction in the immunoregulatory roles of these cells may play a part in the pathogenesis of a subset of patients with IBD. The role of myeloid-derived suppressor cells, initially described in cancer, have been shown to play an important role in the balancing of effector and regulatory T cells in inflammation as well, and their role in IBD is also explored. The potential for future cell-based therapies for IBD is enhanced by the advances being made in the understanding of the innate immune system in the intestine.

Reprogramming of monocytes by GM-CSF contributes to regulatory immune functions during intestinal inflammation.

Human and murine studies showed that GM-CSF exerts beneficial effects in intestinal inflammation. To explore whether GM-CSF mediates its effects via monocytes, we analyzed effects of GM-CSF on monocytes in vitro and assessed the immunomodulatory potential of GM-CSF-activated monocytes (GMaMs) in vivo. We used microarray technology and functional assays to characterize GMaMs in vitro and used a mouse model of colitis to study GMaM functions in vivo. GM-CSF activates monocytes to increase adherence, migration, chemotaxis, and oxidative burst in vitro, and primes monocyte response to secondary microbial stimuli. In addition, GMaMs accelerate epithelial healing in vitro. Most important, in a mouse model of experimental T cell-induced colitis, GMaMs show therapeutic activity and protect mice from colitis. This is accompanied by increased production of IL-4, IL-10, and IL-13, and decreased production of IFN-γ in lamina propria mononuclear cells in vivo. Confirming this finding, GMaMs attract T cells and shape their differentiation toward Th2 by upregulating IL-4, IL-10, and IL-13 in T cells in vitro. Beneficial effects of GM-CSF in Crohn's disease may possibly be mediated through reprogramming of monocytes to simultaneously improved bacterial clearance and induction of wound healing, as well as regulation of adaptive immunity to limit excessive inflammation.

TFF2 deficiency exacerbates weight loss and alters immune cell and cytokine profiles in DSS colitis, and this cannot be rescued by wild-type bone marrow.

The trefoil factor TFF2 is a member of a tripartite family of small proteins that is produced by the stomach and the colon. Recombinant TFF2, when applied intrarectally in a rodent model of hapten colitis, hastens mucosal healing and reduces inflammatory indexes. Additionally, TFF2 is expressed in immune organs, supporting a potential immunomodulatory and reparative role in the bowel. In this study we confirm that TFF2 is expressed in the colon and is specifically enriched in epithelial cells relative to colonic leukocytes. TFF2-deficient, but not TFF1-deficient, mice exhibit a more severe response to acute or chronic dextran sulfate (DSS)-induced colitis that correlates with a 50% loss of expression of TFF3, the principal colonic trefoil. In addition, the response to acute colitis is associated with altered expression of IL-6 and IL-33, but not other inflammatory cytokines. While TFF2 can reduce macrophage responsiveness and block inflammatory cell recruitment to the colon, the major role in limiting the susceptibility to acute colitis appears to be maintenance of barrier function. Bone marrow transfer experiments demonstrate that leukocyte expression of TFF2 is not sufficient for prevention of colitis induction but, rather, that the gastrointestinal epithelium is the primary source of TFF2. Together, these findings illustrate that epithelial TFF2 is an important endogenous regulator of gut mucosal homeostasis that can modulate immune and epithelial compartments. Because of its extreme stability, even in the corrosive gut lumen, TFF2 is an attractive candidate as an oral therapeutic scaffold for future drug development in the treatment of inflammatory bowel disease.

Granulocyte Macrophage Colony-Stimulating Factor-Activated CD39+/CD73+ Murine Monocytes Modulate Intestinal Inflammation via Induction of Regulatory T Cells.

BACKGROUND & AIMS: Granulocyte macrophage colony-stimulating factor (GM-CSF) treatment induces clinical response in patients with active Crohn's disease. To explore whether monocytes mediate GM-CSF effects in vivo, we used a mouse model of chronic colitis induced by dextran sulfate sodium (DSS). METHODS: Murine bone marrow-derived monocytes were activated with GM-CSF in vitro, and gene expression, phenotype, and function of GM-CSF-activated monocytes (GMaM) were analyzed. Therapeutic effects of GMaM were assessed in a model of chronic colitis induced by repeated cycles of DSS. Monocytes were administered intravenously and their immunomodulatory functions were evaluated in vivo by clinical monitoring, histology, endoscopy, immunohistochemistry, and expression of inflammatory markers in the colon. The distribution of injected monocytes in the intestine was measured by in vivo imaging. RESULTS: GMaM expressed significantly higher levels of anti-inflammatory molecules. Production of reactive oxygen species was also increased while phagocytosis and adherence were decreased. GMaM up-regulated CD39 and CD73, which allows the conversion of adenosine triphosphate into adenosine and coincided with the induction of Foxp3+ (forkhead-box-protein P3 positive) regulatory T cells (Treg) in cocultures of GMaM and naive T cells. In chronic DSS-induced colitis, adoptive transfer of GMaM led to significant clinical improvement, as demonstrated by reduced weight loss, inflammatory infiltration, ulceration, and colon shrinkage. As GMaM migrated faster and persisted longer in the inflamed intestine compared with control monocytes, their presence induced Treg generation in vivo. CONCLUSIONS: GM-CSF leads to specific monocyte activation that modulates experimental colitis via mechanisms that include the induction of Treg. We demonstrate a possible mechanism of Treg induction through CD39 and CD73 expression on monocytes.

Linking immunity, epigenetics, and cancer in inflammatory bowel disease.

Most of what is known about the pathogenesis of inflammatory bowel disease (IBD) pertains to complex interplay between host genetics, immunity, and environmental factors. Epigenetic modifications play pivotal roles in intestinal immunity and mucosal homeostasis as well as mediating gene-environment interactions. In this article, we provide a historical account of epigenetic research either directly related or pertinent to the pathogenesis and management of IBD. We further collate emerging evidence supporting roles for epigenetic mechanisms in relevant aspects of IBD biology, including deregulated immunity, host-pathogen recognition and mucosal integrity. Finally, we highlight key epigenetic mechanisms that link chronic inflammation to specific IBD comorbidities, including colitis-associated cancer and discuss their potential utility as novel biomarkers or pharmacologic targets in IBD therapy.

Granulocyte macrophage colony-stimulating factor and the intestinal innate immune cell homeostasis in Crohn's disease.

Current literature consolidates the view of Crohn's disease (CD) as a form of immunodeficiency highlighting dysregulation of intestinal innate immunity in the pathogenesis of CD. Intestinal macrophages derived from blood monocytes play a key role in sustaining the innate immune homeostasis in the intestine, suggesting that the monocyte/macrophage compartment might be an attractive therapeutic target for the management of CD. Granulocyte macrophage colony-stimulating factor (GM-CSF) is a hematopoietic growth factor that also promotes myeloid cell activation, proliferation, and differentiation. GM-CSF has a protective effect in human CD and mouse models of colitis. However, the role of GM-CSF in immune and inflammatory reactions in the intestine is not well defined. Beneficial effects exerted by GM-CSF during intestinal inflammation could relate to modulation of the mucosal barrier function in the intestine, including epithelial cell proliferation, survival, restitution, and immunomodulatory actions. The aim of this review is to summarize potential mechanistic roles of GM-CSF in intestinal innate immune cell homeostasis and to highlight its central role in maintenance of the intestinal immune barrier in the context of immunodeficiency in CD.