Altered Th1/Th2 cytokine profiles in the intestinal mucosa of patients with inflammatory bowel disease as assessed by quantitative reversed transcribed polymerase chain reaction (RT-PCR)

Marine Algae and Deriving Biomolecules for the Management of Inflammatory Bowel Diseases: Potential Clinical Therapeutics to Decrease Gut Inflammatory and Oxidative Stress Markers?

The term "inflammatory bowel disease" (IBD) describes a class of relapse-remitting conditions that affect the gastrointestinal (GI) tract. Among these, Crohn's disease (CD) and ulcerative colitis (UC) are two of the most globally prevalent and debilitating conditions. Several articles have brought attention to the significant role that inflammation and oxidative stress cooperatively play in the development of IBD, offering a different viewpoint both on its etiopathogenesis and on strategies for the effective treatment of these conditions. Marine ecosystems may be a significant source of physiologically active substances, supporting the search for new potential clinical therapeutics. Based on this evidence, this review aims to comprehensively evaluate the activity of marine algae and deriving biomolecules in decreasing pathological features of CD and UC. To match this purpose, a deep search of the literature on PubMed (MEDLINE) and Google Scholar was performed to highlight primary biological mechanisms, the modulation of inflammatory and oxidative stress biochemical parameters, and potential clinical benefits deriving from marine species. From our findings, both macroalgae and microalgae have shown potential as therapeutic solutions for IBD due to their bioactive compounds and their anti-inflammatory and antioxidant activities which are capable of modulating markers such as cytokines, the NF-κB pathway, reactive oxidative and nitrosative species (ROS and RNS), trefoil factor 3 (TFF3), lactoferrin, SIRT1, etc. However, while we found promising preclinical evidence, more extensive and long-term clinical studies are necessary to establish the efficacy and safety of marine algae for IBD treatment.

Fibrosis in IBD: from pathogenesis to therapeutic targets

BACKGROUND

Intestinal fibrosis resulting in stricture formation and obstruction in Crohn's disease (CD) and increased wall stiffness leading to symptoms in ulcerative colitis (UC) is among the largest unmet needs in inflammatory bowel disease (IBD). Fibrosis is caused by a multifactorial and complex process involving immune and non-immune cells, their soluble mediators and exposure to luminal contents, such as microbiota and environmental factors. To date, no antifibrotic therapy is available. Some progress has been made in creating consensus definitions and measurements to quantify stricture morphology for clinical practice and trials, but approaches to determine the degree of fibrosis within a stricture are still lacking.

OBJECTIVE

We herein describe the current state of stricture pathogenesis, measuring tools and clinical trial endpoints development.

DESIGN

Data presented and discussed in this review derive from the past and recent literature and the authors' own research and experience.

RESULTS AND CONCLUSIONS

Significant progress has been made in better understanding the pathogenesis of fibrosis, but additional studies and preclinical developments are needed to define specific therapeutic targets.

Metabolomics study reveals increased deoxycholic acid contributes to deoxynivalenol-mediated intestinal barrier injury

AIMS

Deoxynivalenol (DON), namely vomitoxin, is one of the most prevalent fungal toxins in cereal crops worldwide. However, the underlying toxic mechanisms of DON remain largely unknown.

MAIN METHODS

DON exposure-caused changes in the murine plasma metabolome and gut microbiome were investigated by an LC-MS/MS-based nontargeted metabolomics approach and sequencing of 16S rRNA in fecal samples, respectively. Cellular models were then used to validate the findings from the metabolomics study.

KEY FINDINGS

DON exposure increased intestinal barrier permeability evidenced by its-mediated decrease in colonic Claudin 5 and E-cadherin, as well as increases in colonic Ifn-γ, Cxcl9, Cxcl10, and Cxcr3. Furthermore, DON exposure resulted in a significant increase in murine plasma levels of deoxycholic acid (DCA). Also, DON exposure led to gut microbiota dysbiosis, which was associated with DON exposure-caused increase in plasma DCA. In addition, we found not only DON but also DCA dose-dependently caused a significant increase in the levels of IFN-γ, CXCL9, CXCL10, and/or CXCR3, as well as a significant decrease in the expression levels of Claudin 5 and/or E-cadherin in the human colonic epithelial cells (NCM460).

SIGNIFICANCE

DON-mediated increase in DCA contributes to DON-caused intestinal injury. DCA may be a potential therapeutic target for DON enterotoxicity.

Beneficial effects of alpha-1 antitrypsin therapy in a mouse model of colitis-associated colon cancer

BACKGROUND

It is widely accepted that chronic inflammatory bowel diseases significantly higher a risk for colorectal cancer development. Among different types of treatments for patients with colon cancer, novel protein-based therapeutic strategies are considered.

AIM

To explore the effect of human plasma alpha-1 antitrypsin (AAT) protein in the chemically induced mouse model of colorectal cancer.

METHODS

BALB/c mice with azoxymethane/dextran sodium sulfate (AOM/DSS)-induced colitis-associated colorectal cancer (CAC), we intraperitoneally treated with commercial preparation of human plasma AAT (4 mg per mouse). Effects of this therapy were evaluated histologically, and by immunohistochemical and gene expression assays.

RESULTS

When compared with non-treated controls, AOM/DSS mice receiving AAT therapy exhibited significantly longer colons, and less anal bleeding. Concurrently, AAT-treated mice had significantly fewer polyps, and lower numbers of large colon tumors. Immunohistochemical examinations of colon tissues showed significantly lower neutrophil counts, more granzyme B-positive but fewer MMP9 (gelatinase B)-positive cancer cells and lower numbers of apoptotic cells in mice receiving AAT therapy. The expression levels of IL4 were significantly higher while TNFA was slightly reduced in tumor tissues of AOM/DSS mice treated with AAT than in AOM/DSS mice.

CONCLUSION

Human AAT is an acute phase protein with a broad-protease inhibitory and immunomodulatory activities used as a therapeutic for emphysema patients with inherited AAT deficiency. Our results are consistent with previous findings and support an idea that AAT alone and/or in combination with available anti-cancer therapies may represent a new personalized approach for patients with colitis-induced colon cancer.

Collagen VI promotes recovery from colitis by inducing lymphangiogenesis and drainage of inflammatory cells

Despite a number of studies providing evidence that the extracellular matrix (ECM) is an active player in the pathogenesis of intestinal inflammation, knowledge on the actual contribution of specific ECM molecules in the progression of inflammatory bowel disease (IBD) remains scant. Here, we investigated the role of a major ECM protein, collagen VI (ColVI), in gut homeostasis and elucidated the impact of its deregulation on the pathophysiology of IBD. To this end, we combined in vivo and ex vivo studies on wild type and ColVI-deficient (Col6a1-/- ) mice both under physiological conditions and during experimentally induced acute colitis and its subsequent recovery, by means of gut histology and immunostaining, gene expression, bone marrow transplantation, flow cytometry of immune cell subpopulations, and lymph flow assessment. We found that ColVI displayed dynamic expression and ECM deposition during the acute inflammatory and recovery phases of experimentally induced colitis, whereas the genetic ablation of ColVI in Col6a1 null mice impaired the functionality of lymphatic vessels, which in turn affected the resolution of inflammation during colitis. Based on these findings, we investigated ColVI expression and deposition in ileal specimens from two cohorts of patients affected by Crohn's disease (CD) and correlated ColVI abundance to clinical outcome. Our results show that high ColVI immunoreactivity in ileal biopsies of CD patients at diagnosis correlates with increased risk of surgery and that ColVI expression in biopsies taken at the resection margin during surgery, and showing inactive disease, predict disease recurrence. Our data unveil a key role for ColVI in the intestinal microenvironment, where it is involved in lymphangiogenesis and intestinal inflammation. Altogether, these findings point at the dysregulation of ColVI expression as a novel factor contributing to the onset and maintenance of inflammation in CD via mechanisms impinging on the modulation of inflammatory cell recruitment and function. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Mucosal Interleukin-10 depletion in steroid-refractory Crohn's disease patients

BACKGROUND

Previous studies suggested that Interleukin-10 (IL-10) depletion in Crohn's disease (CD) could predict outcome.

AIM

To determine IL-10 in blood and at different intestinal locations in patients with active CD and to assess its potential prognostic capacity to identify aggressive CD.

METHODS

Twenty-three patients with CD were included. Ulcerative colitis (UC), infectious colitis and healthy individuals acted as controls. Serum and mucosal samples were taken at baseline and 1 month after steroid initiation in CD patients. Patients were classified according to steroid response. Control samples were obtained from different intestinal locations. IL-10 expression was measured with real-time polymerase chain reaction, immunofluorescence (intestine) and ELISA (serum, biopsy cultures' supernatants and tissue homogenates).

RESULTS

CD and UC showed an increase in IL-10 messenger RNA (mRNA) versus controls (p < .0001) in mucosa, whereas IL-10 protein secretion was increased in all types of intestinal inflammation (p < .001). No differences in IL-10 mRNA were found in CD at baseline regarding steroid response, but levels decreased in non-responders versus responders (p = .027) and were restored with rescue therapy. Serum IL-10 was increased in steroid-refractory CD at baseline and after treatment.

CONCLUSIONS

Abnormal IL-10 levels in refractory patients in both mucosa and blood have physiopathological relevance and may have potential clinical applications.

The regulatory mechanism and potential application of IL-23 in autoimmune diseases

IL-23 is a heterodimeric pro-inflammatory cytokine secreted by dendritic cells and macrophages that belongs to the IL-12 family. It has pro-inflammatory effects and is a key cytokine and upstream regulatory cytokine involved in protective immune responses, stimulating the differentiation and proliferation of downstream effectors such as Th17 cells. It is expressed in various autoimmune diseases such as psoriasis, systemic lupus erythematosus (SLE), rheumatoid arthritis (RA). The IL-23/TH17 axis formed by IL-23 and TH17 has been confirmed to participate in autoimmune diseases pathogenesis. IL-23R is the receptor for IL-23 and plays an activating role. Targeting IL-23 is currently the main strategy for the treatment of various autoimmune diseases. In this review we summarized the mechanism of action and clinical application potential of IL-23 in autoimmune diseases by summarizing the latest research results and reviewing the literature, which would help to further understand IL-23 and provide a theoretical basis for future clinical targeting and drug development.

Cytokine Mixtures Mimicking the Local Milieu in Patients with Inflammatory Bowel Disease Impact Phenotype and Function of Mesenchymal Stromal Cells

Locally applied mesenchymal stromal cells (MSCs) have the capacity to promote the healing of perianal fistulas in Crohn’s disease (CD) and are under clinical development for the treatment of proctitis in ulcerative colitis (UC). Despite these clinical advances, the mechanism of action of local MSC therapy in inflammatory bowel disease (IBD) is largely unknown. We hypothesized that the local cytokine environment in IBD patients affects the immunomodulatory properties of MSCs. To evaluate this, 11 cytokines were analyzed in inflamed tissues obtained from CD and UC patients. Based on the identified cytokine profiles 4 distinct cytokine mixtures that mimic various inflammatory IBD environments were established. Next, MSCs were cultured in the presence of either of these 4 cytokine mixtures after which the expression of immunomodulatory and tissue regenerative molecules and the capacity of MSCs to modulate T-cell proliferation and dendritic cell (DC) differentiation were assessed. Our data show that MSCs respond, in a cytokine-specific manner, by upregulation of immunomodulatory and tissue regenerative molecules, including cyclooxygenase-2, indoleamine 2,3-dioxygenase, and transforming growth factor-β1. Functional studies indicate that MSCs exposed to a cytokine profile mimicking one of the 2 UC cytokine milieus were less effective in inhibition of DC differentiation. In conclusion, our data indicate that cytokine mixes mimicking the local cytokine milieus of inflamed UC colonic or CD fistulas tissues can differentially affect the immunomodulatory and tissue regenerative characteristics of MSCs. These data support the hypothesis that the local intestinal cytokine milieu serves as a critical factor in the efficacy of local MSC treatment.

Inflammatory bowel disease and immune-mediated inflammatory diseases: looking at the less frequent associations

Patients with inflammatory bowel disease (IBD) often have other immune-mediated inflammatory diseases (IMIDs), and the prevalence of any IMID is higher in IBD patients than in the general population. IBD and other IMIDs involve alterations in innate and adaptive immune responses. Their co-occurrence depends on shared immune and inflammatory processes, pathogenic mechanisms, and genetic and environmental risk factors, including drugs, especially tumor necrosis factor inhibitors. The more common IMIDs associated with IBD have been widely described, so this review focuses on the less frequent associations. The IMIDs discussed here are skin disorders (psoriasis, atopic dermatitis, vitiligo, epidermolysis bullosa acquisita, cutaneous polyarteritis nodosa, and hidradenitis suppurativa), hepato-pancreatic diseases (autoimmune hepatitis, granulomatous hepatitis, and autoimmune pancreatitis), endocrine diseases (autoimmune thyroid diseases, and type 1 diabetes mellitus), multiple sclerosis, and respiratory diseases (asthma, bronchiectasis, and interstitial pneumonia). The early detection of IMIDs in IBD patients is important to prevent their deleterious clinical course and limit their psychological impact. Care for IBD patients with IMIDs should be multispecialist, with a single therapeutic strategy instead of treating each disease separately.

Gene expression analysis of intestinal IL-8, IL-17 A and IL-10 in patients with celiac and inflammatory bowel diseases

BACKGROUND

Celiac disease (CeD) and inflammatory bowel disease (IBD) are accompanied by impaired immune responses. To study the immune regulation of these diseases, we evaluated the expression levels of pro-inflammatory (IL-8 and IL-17 A) and anti-inflammatory (IL-10) cytokines in intestinal biopsy specimens of CeD and IBD patients in comparison to healthy subjects.

METHODS AND RESULTS

Intestinal biopsies were collected from 33 patients with IBD, 47 patients with CeD, and 20 healthy individuals. Total RNA was extracted and mRNA expression levels of IL-8, IL-17 A and IL-10 were assessed by qPCR. P-value < 0.05 was considered statistically significant. The expression levels of IL-8 and IL-17 A were higher in biopsies of IBD (UC and CD) and CeD patients compared to the control group (P < 0.05). IBD patients (UC and CD) had higher IL-8 intestinal level than CeD patients (P < 0.0001 and P = 0.0007, respectively). The expression of IL-10 was significantly down-regulated in intestinal biopsies of CeD and IBD patients compared with controls (P < 0.001). In addition, the expression level of this cytokine was significantly lower in IBD patients (P < 0.001 for UC patients and P < 0.0001 for CD patients) than CeD group.

CONCLUSIONS

The three selected pro- and anti-inflammatory cytokines showed a similar expression pattern in both IBD and CeD patients. As IBD and CeD are immune-mediated disorders and are accompanied by inflammatory events, the understanding of the similarities and differences among them can help researchers to find out useful candidate therapeutic protocols. We suggest that larger cohort studies be organized to achieve more insights into this regulation.

Enteric Glial Cells in Immunological Disorders of the Gut

Enteric glial cells (EGCs) are one of the major cell types of neural crest lineage distributed in the gastrointestinal tract. EGCs represent an integral part of the enteric nervous system (ENS) and significantly outnumber ENS neurons. Studies have suggested that EGCs would exert essential roles in supporting the survival and functions of the ENS neurons. Notably, recent evidence has begun to reveal that EGCs could possess multiple immune functions and thereby may participate in the immune homeostasis of the gut. In this review article, we will summarize the current evidence supporting the potential involvement of EGCs in several important immunological disorders, including inflammatory bowel disease, celiac disease, and autoimmune enteropathy. Further, we highlight critical questions on the immunological aspects of EGCs that warrant future research attention.

Down-regulation of the expression of cyclooxygenase-2 and prostaglandin E2 by interleukin-4 is mediated via a reduction in the expression of prostanoid EP4 receptors in HCA-7 human colon cancer cells

Chronic inflammatory bowel disease (IBD), which is characterized by prolonged inflammation of the gastrointestinal tract is associated with an increased risk of colorectal cancer. Recent studies revealed that the pathology of IBD is caused by hyperactivated immune responses mediated by differentiated CD4⁺ naïve helper T cells, such as Th1 and Th17 cells, but not Th2 cells. The human E-type prostanoid 4 (EP4) receptor and its pathways have also been implicated in and/or associated with the early developmental stages of colorectal cancer along with increases in the levels of prostaglandin E₂ (PGE₂) and cyclooxygenase-2 (COX-2), the hallmarks of colorectal carcinogenesis. In the present study, using an in silico analysis and pharmacological experiments, we demonstrated that interleukin (IL)-4, a signature cytokine of Th2 cells, down-regulated the expression of COX-2 and PGE₂ in the human colon cancer cell line, HCA-7. This result may be attributed to a reduction in the expression of prostanoid EP4 receptors through the induction of hypoxia inducible factor-1α via the interleukin-4 receptor-stimulated activation of signal transducer and activator of transcription 6. However, another major Th2 cytokine IL-13 had no effect on the expression of COX-2 or prostanoid EP4 receptors in HCA-7 cells. Therefore, instead of the hyperactivation of Th1/Th17 cells, the deactivation/down-regulation of Th2 cells followed by a decrease in the production of IL-4 in IBD may play a role in the cancerous transformation of cells, at least in prostanoid EP4 receptor-overactivated tumorigenesis.

FOXP3 variants are independently associated with transforming growth factor Β1 plasma levels in female patients with inflammatory bowel disease

OBJECTIVE

The aim of this study was to evaluate the association of -924 G>A (rs2232365) and -3279 C>A (rs3761548) FOXP3 variants with IBD susceptibility, clinical and endoscopic activity, and IL-10 and TGF-β1 plasma levels.

METHOD

The study included 110 IBD female patients, 60 with Ulcerative Colitis (UC) and 50 with Crohn's Disease (CD), and 154 female controls. FOXP3 variants were determined with Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Plasma levels of IL-10 and TGF-β1 were determined using immunofluorimetric assay.

RESULTS

AA genotype of rs2232365 and rs3761548 was associated with CD (OR = 3.147, 95% CI 1.015-9.758, p = 0.047) and UC (OR = 3.221, 95% CI 1.050-9.876, p = 0.041) susceptibility, respectively. However, were not associated with TGF-β1 and IL-10 levels, and endoscopic/clinical activity disease. GAGA haplotype was associated with IBD (OR = 4.003, 95% CI 1.100-14.56, p = 0.035) and UC susceptibility (OR = 6.107, 95% CI 1.609-23.18, p = 0.008). In addition, IBD patients with the GAGA haplotype had lower TGF-β1 levels (p = 0.041). Moreover, G/C haplotype (dominant model) had a protective effect of 60% in CD susceptibility and lower Endoscopic Severity Index.

CONCLUSIONS

These results suggest that FOXP3 variants could exert a role in the Treg, which could be one of the factors involved in the susceptibility and pathogenesis of IBD.

Present and Future Therapeutic Approaches to Barrier Dysfunction

There is converging and increasing evidence, but also uncertainty, for the role of abnormal intestinal epithelial barrier function in the origin and development of a growing number of human gastrointestinal and extraintestinal inflammatory disorders, and their related complaints. Despite a vast literature addressing factors and mechanisms underlying changes in intestinal permeability in humans, and its connection to the appearance and severity of clinical symptoms, the ultimate link remains to be established in many cases. Accordingly, there are no directives or clinical guidelines related to the therapeutic management of intestinal permeability disorders that allow health professionals involved in the management of these patients to carry out a consensus treatment based on clinical evidence. Instead, there are multiple pseudoscientific approaches and commercial propaganda scattered on the internet that confuse those affected and health professionals and that often lack scientific rigor. Therefore, in this review we aim to shed light on the different therapeutic options, which include, among others, dietary management, nutraceuticals and medical devices, microbiota and drugs, and epigenetic and exosomes-manipulation, through an objective evaluation of the scientific publications in this field. Advances in the knowledge and management of intestinal permeability will sure enable better options of dealing with this group of common disorders to enhance quality of life of those affected.

The effects of twenty-four nutrients and phytonutrients on immune system function and inflammation: A narrative review

BACKGROUND AND AIM

Recently, optimal immune function has become a primary focus of worldwide attention not only in the prevention of chronic disease but also as one strategy to reduce the severity of acute illness. Inflammation, a process largely controlled by the immune system, has long been studied and recognized for its role in chronic disease. Optimizing immune function or managing inflammation using individual nutrients and phytonutrients is not well understood by the average person. Thus, this narrative literature review summarizes many of the more recent findings about how certain nutrients and phytonutrients affect immune function and inflammation, and how they may best be utilized considering the growing worldwide interest in this topic.

METHODS

A comprehensive literature search of PubMed was performed to find clinical trials in humans that assessed the effect of nutrients and phytonutrients on immune function and inflammation, in individuals with acute and chronic health conditions, published in English between 2000 and 2020. Two independent reviewers evaluated the articles for their inclusion.

RESULTS

Eighty-seven articles were summarized in this narrative review. In total 24 nutrients and phytonutrients were included in the study, that is, acetyl-L-carnitine, Aloe vera polysaccharides, beta-glucans, bilberry, black seed oil, coenzyme Q10, curcumin (turmeric), frankincense, garlic, ginger, hydrolyzed rice bran, isoflavones, lipoic acid, mistletoe, N-acetyl cysteine, omega-3 fatty acids, resveratrol, selenium, shiitake mushroom and its derivatives, Vitamin B12, Vitamin C, Vitamin D3 (cholecalciferol), Vitamin E (d-alpha- and gamma-tocopherol), and zinc. Some of the noteworthy immune function and anti-inflammatory responses to these interventions included modulation of nuclear factor-Kappa B, tumor necrosis factor-a, interferon-g, interleukin-6, and CD4+ T cells, among others. These findings are not completely consistent or ubiquitous across all patient populations or health status.

CONCLUSIONS

Based on this review, many nutrients and phytonutrients are capable of significantly modulating immune function and reducing inflammation, according to multiple biomarkers in clinical trials in different populations of adults with varying health statuses. Thus, dietary supplementation may serve as an adjunct to conventional pharmaceutical or medical therapies, but evaluation of risks and benefits for each person and health status is necessary. Additional larger studies are also needed to investigate the safety and efficacy of nutritional compounds in various health conditions, with emphases on potential drug-supplement interactions and clinical endpoints.

RELEVANCE FOR PATIENTS

As demonstrated in the reviewed clinical trials, patients of various health challenges with a wide range of severity may benefit from select nutrients and phytonutrients to improve their immune function and reduce inflammation.

Novel mechanisms and clinical trial endpoints in intestinal fibrosis

The incidence of inflammatory bowel diseases (IBD) worldwide has resulted in a global public health challenge. Intestinal fibrosis leading to stricture formation and bowel obstruction is a frequent complication in Crohn's disease (CD), and the lack of anti-fibrotic therapies makes elucidation of fibrosis mechanisms a priority. Progress has shown that mesenchymal cells, cytokines, microbial products, and mesenteric adipocytes are jointly implicated in the pathogenesis of intestinal fibrosis. This recent information puts prevention or reversal of intestinal strictures within reach through innovative therapies validated by reliable clinical trial endpoints. Here, we review the role of immune and non-immune components of the pathogenesis of intestinal fibrosis, including new cell clusters, cytokine networks, host-microbiome interactions, creeping fat, and their translation for endpoint development in anti-fibrotic clinical trials.

Factors Associated with Inflammatory Bowel Disease Flare During Pregnancy Among Women with Preconception Remission

BACKGROUND

The factors associated with inflammatory bowel diseases (IBD) relapse throughout gestation in those with preconception remission remain unknown.

AIMS

We aimed to investigate disease and pregnancy course among IBD women with quiescent disease at conception.

METHODS

Women with IBD attending a multidisciplinary clinic for preconception, antenatal and postnatal treatment were prospectively recruited during 2011-2018.

RESULTS

Overall, 298 women with IBD with quiescent disease at the time of conception constituted the study cohort. Of these, 112 (37.6%) women experienced disease flare during pregnancy. The risk of disease relapse was higher in those with ulcerative colitis (UC) as compared to those with Crohn's disease (CD) (48.1% vs. 31.8%, P = 0.005). The proportion of women with prior IBD-related gastrointestinal surgery was lower in those who experienced disease flare up (13.4% vs. 26.3%, P = 0.009). The use of biologic therapy at the time of conception was associated with lower rates of disease relapse (25.0% vs. 43.9%, P = 0.001). In multivariate analysis, use of conventional medications or no treatment (aOR [95% CI]: 2.0 (1.12, 3.57), P = 0.02) and lack of prior history of IBD-related surgery (aOR [95% CI]: 3.13 (1.37, 7.14), P = 0.007) were independently positively associated with disease relapse. Rates of hospitalization during pregnancy (21.4% vs. 2.2%, P < 0.001) and preterm delivery (22.3% vs. 9.1%, P = 0.002) were higher, and birthweight was lower (median 2987 vs. 3153 grams, P = 0.05) in those with disease flare as compared to those who maintained remission.

CONCLUSION

Prior IBD-related surgery and biologic therapy were found as independent protective factors against relapse during pregnancy among women with quiescent disease at conception.

Glucocorticoid-Induced Leucine Zipper as a Druggable Target in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders with a complex pathogenesis, affecting people of all ages. They are characterized by alternating phases of clinical relapse and remission, depending on the fine balance between immune cells and the gut microbiota. The cross talk between cells of the immune system and the gut microbiota can result in either tolerance or inflammation, according to multifactorial triggers, ranging from environmental factors to genetic susceptibility. Glucocorticoid (GC) administration remains the first-line treatment for IBDs, although long-term use is limited by development of serious adverse effects. Recently, new alternative pharmacological therapies have been developed, although these are not always effective in IBD patients. There is a constant demand for effective new drug targets to guarantee total remission and improve the quality of life for IBD patients. The glucocorticoid-induced leucine zipper (GILZ) has been implicated as a promising candidate for this purpose, in view of its powerful anti-inflammatory effects that mimic those of GCs while avoiding their unwanted adverse reactions. Here we present and discuss the latest findings about the involvement of GILZ in IBDs.

The role of cytokine and immune responses in intestinal fibrosis

The rapidly increasing incidence of inflammatory bowel disease (IBD) in South America, eastern Europe, Asia, and Africa has resulted in a global public health challenge. Intestinal fibrosis is a common complication in patients with long-term IBD, which may develop into stenosis and subsequent obstruction. Hitherto, the origin of IBD is unclear and several factors may be involved, including genetic, immune, environmental and microbial influences. Little is known about how the recurrent inflammation in patients with IBD develops into intestinal fibrosis and currently, there is no suitable treatment to reverse intestinal fibrosis in these patients. Here, we review the role of immune components in the pathogenesis of IBD and intestinal fibrosis, including cytokine networks, host-microbiome interactions, and immune cell trafficking.

Characteristics and Long-Term Outcomes of Pregnancy-Onset Inflammatory Bowel Disease: A Case-Control Study

BACKGROUND

Inflammatory bowel disease (IBD) frequently affects women during their reproductive years. Although the impact of pregnancy in patients with established IBD has been widely studied, the characteristics and outcomes of patients who develop a new diagnosis of IBD during pregnancy or the postpartum year ("pregnancy-onset") is not well characterized.

METHODS

We identified all patients with pregnancy-onset IBD between 2006 and 2018 at 2 major academic referral centers. Patient and disease characteristics were abstracted and compared to those of control patients with IBD not diagnosed during pregnancy or postpartum. Diagnostic and therapeutic interventions were noted, as were long-term outcomes including disease treatment course, hospitalizations, and surgery.

RESULTS

We identified 50 patients with pregnancy-onset IBD and 100 control patients matched for year of diagnosis. The mean age of diagnosis and duration of follow-up was similar among both patients and control patients (aged 30.4 vs 28.5 years). Among patients with pregnancy-onset disease, 30% noted symptom onset in the first trimester, 22% in the second, 24% in the third, and 24% in the postpartum year. Patients with pregnancy-onset IBD were more likely to be diagnosed with ulcerative colitis compared with control patients (76% vs 56%; P = 0.02). On multivariable analysis, pregnancy onset-disease had a 4-fold increase in the risk of hospitalization (28% vs 13%; adjusted odds ratio 4.18; 95% confidence interval, 1.26-13.91). This increased risk persisted even after excluding any index hospitalizations during pregnancy.

CONCLUSIONS

Patients with pregnancy-onset IBD more commonly develop ulcerative colitis and have a higher risk of disease-related hospitalizations.

Interplay between Cytokine Circuitry and Transcriptional Regulation Shaping Helper T Cell Pathogenicity and Plasticity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic disorder manifested as Crohn’s disease (CD) and ulcerative colitis (UC) characterized by intestinal inflammation and involves a dysregulated immune response against commensal microbiota through the activation of CD4 T helper cells. T helper cell differentiation to effector or regulatory phenotypes is controlled by cytokine networks and transcriptional regulators. Distinct polarized T helper cells are able to alter their phenotypes to adapt to diverse and fluctuating physiological environments. T helper cells exhibit intrinsic instability and flexibility to express cytokines of other lineages or transdifferentiate from one T helper cell type to another in response to various perturbations from physiological cytokine milieu as a means of promoting local immunity in response to injury or ensure tissue homeostasis. Furthermore, functional plasticity and diversity of T helper cells are associated with pathogenicity and are critical for immune homeostasis and prevention of autoimmunity. In this review, we provide deeper insights into the combinatorial extrinsic and intrinsic signals that control plasticity and transdifferentiation of T helper cells and also highlight the potential of exploiting the genetic reprogramming plasticity of T helper cells in the treatment of IBD.

Impact of smoking cigarette on the mRNA expression of cytokines in mucosa of inflammatory bowel disease

It is well known that smoking is the risk factor in the development and clinical course of Crohn s disease (CD), but on the other hand, smoking is a protective factor against ulcerative colitis (UC). The pathways that are influenced by smoking in CD and UC are poorly understood. The aim of our study was to analyse the influence of smoking on the mRNA expression of cytokines in mucosa in patients with CD and UC. We performed a cross-sectional study. The cohort consisted of 86 IBD patients (48 CD patients and 38 UC patients) and took place at the IBD Centre at the University Hospital Bratislava-Ružinov. We took the demographic and clinical data of each patient, including information about their smoking habits. We performed a colonoscopy on each patient and took biopsies from both inflamed and non-inflamed sigma (CD, UC) and terminal ileum (CD). mRNA was extracted from mucosal biopsy samples for each cytokine and was normalized to a housekeeping gene (GAPDH). Finally, we compared the mRNA expression of target cytokines in the mucosa of smokers and non-smokers in IBD patients. Smokers with Crohn s disease have a significantly higher mRNA expression of pro-inflammatory cytokine TNF ? (p=0.003) in inflamed mucosa in sigma compared with non-smokers. In smokers with ulcerative colitis, we observed significantly higher mRNA expression of anti-inflammatory cytokine IL 10 (p=0.022) in non-inflamed mucosa of sigma. Similarly, smokers with UC have a significantly decreased mRNA expression of cytokine TLR 2 (p=0.024) and CCR1 (p=0.049) in non-inflamed mucosa of sigma. Based on our results, smoking has a positive influence on cessation and the clinical course of UC due to the stimulation of anti-inflammatory cytokine IL 10 in mucosa. On the other hand, smokers with CD have a higher expression of pro-inflammatory cytokine TNF ?, which could be associated with a worsening of the disease and response to therapy.

Specific T-Cell Subsets Can Predict the Efficacy of Anti-TNF Treatment in Inflammatory Bowel Diseases

The effect of TNF-blockers on T-lymphocyte subsets is largely unknown in inflammatory bowel diseases (IBDs). The aim of the present study was to analyze the prevalence of T-cell subtypes and their correlation to therapeutic response. Sixty-eight patients with Crohn’s disease (CD), 46 with ulcerative colitis (UC) were enrolled. (1) The clinical course was followed after the initiation of TNF-blockers (prospective study). (2) The immunophenotype was also compared between long-term anti-TNF treated-responders and non-responders (cross-sectional study). The results were compared with those of therapy-naïve patients with active disease and those in remission with non-biological immunosuppressive therapy, and with healthy controls. Fourteen subtypes of peripheral blood T cells were measured with flow cytometry. The prevalence of Th2 and Th17 cells, of HLA-DR- and CD69-positive CD4 and CD8 cells, was higher, whereas the percentage of CD45RA-positive CD4 and CD8 cells was lower in both IBDs than in controls. CD8CD69 cell frequency was lower in remission, and decreased during anti-TNF therapy in CD responders. CD8CD45RO memory cells had higher prevalence in UC non-responders than in those starting anti-TNF. CD4CD45RO percentage < 49.05 at the initiation of TNF-blockers was predictive of a subsequent therapeutic response in CD, and Th2 and Th17 prevalence correlated with the duration of remission on TNF-blockers in UC. This study provided a detailed description of the T-cell composition in IBDs. CD8CD69 prevalence may be an activity marker in CD, and CD4CD45RO, Th2 and Th17 levels could be predictive for a therapeutic response to anti-TNF.

Alpha-linolenic acid given as an anti-inflammatory agent in a mouse model of colonic inflammation

This study examined the relationship between the high-fat, high-sugar diet (HFHSD) and trinitrobenzene sulfonic acid (TNBS) induced mouse colitis, the therapeutic effect of alpha-linolenic acid (ALA) on mouse colitis, and the relationship between HFHSD and hyperlipidemia. We also examined the possible underlying mechanisms behind their interactions. Female BABL/c mice were fed with HFHSD for the 9 weeks. At the same time, ALA treatment (150 or 300 mg/kg) was administered on a daily basis. At the end of the 9 weeks, experimental colitis was induced by the intra-colonic administration of TNBS. Body weight, spleen weight, disease activity index (DAI), histological changes, T-cell-related cytokine level, and lipid profiles were measured after treatment. TNBS induced severe clinical manifestations of colitis and histological damage. Low-ALA (150 mg/kg) administration profoundly ameliorated TNBS-induced clinical manifestations, body weight loss, spleen weight loss, and histological damage. On the contrary, the high-ALA (300 mg/kg) administration did not ameliorate colitis and even exacerbated the symptoms. HFHSD consumption assisted TNBS in changing IL-12, IFN-γ, IL-2, and IL-17A in the liver. As expected, these changes were recovered through low-ALA. In addition, HFHSD had a significant impact on the total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglyceride (TG), which related to the increased risk of hyperlipidemia. In summation, HFHSD exacerbated the TNBS-induced colitis via the Th1/Th17 pathway. The Low-ALA (150 mg/kg) exhibited protective effects against the TNBS-induced colitis via the Th1/Th2/Th17 pathway.

Intratracheal Ovalbumin Administration Induces Colitis Through the IFN-γ Pathway in Mice

Recent studies have reported an increased incidence of inflammatory bowel disease (IBD) in patients with pulmonary diseases. Despite clinical and epidemiological studies of the interplay between colitis and asthma, the diseases' related underlying mechanisms remain unclear. In this study, we evaluated the development of colitis in a model of allergic airway inflammation. We revealed that intratracheal chronic ovalbumin (OVA) exposure induces colitis and allergic airway inflammation. Interestingly, induction of colitis was largely regulated by Th1, rather than Th2 responses, whereas allergic airway inflammation was primarily mediated by Th2 responses. Experiments in Tbx21 (T-bet) and Ifng (IFN-γ) deficient mice have confirmed that IFN-γ is a major mediator involved in OVA-induced colitis. These findings broaden current understanding of allergen induced colitis pathology and could play a role in the development of novel clinical treatment strategies for asthmatic patients who are at risk of developing colitis.

Lower Abundance and Impaired Function of CD71+ Erythroid Cells in Inflammatory Bowel Disease Patients During Pregnancy

BACKGROUND AND AIMS

CD71+ erythroid cells are enriched during pregnancy with immuno suppressive properties. We investigated the frequency and functionality of CD71+ erythroid cells in peripheral blood, cord blood, and placenta of inflammatory bowel disease [IBD] patients versus healthy controls [HCs]. We aimed to determine their role in IBD pathogenesis during pregnancy.

METHODS

Peripheral blood was collected at preconception, the first, second and third trimesters, and postpartum. Cord blood and placental tissues were collected at the time of birth. Cells from different specimens were subjected to immune-phenotyping and functional assays. CD71+ erythroid cells were purified for quantitative polymerase chain reaction [qPCR] analysis. Using an allogeneic mouse model of pregnancy, the effects of CD71+ erythroid cells depletion on intestinal homeostasis and dysbiosis was studied.

RESULTS

IBD patients had lower CD71+ erythroid cells during pregnancy compared with HCs. Placenta and cord blood CD71+ erythroid cells from IBD patients exhibited impaired functionality and expressed lower inhibitory molecules including VISTA, TGF-β, and reactive oxygen species [ROS]. Lower CD71+ erythroid cells were correlated with reduced regulatory T cells and increased immune-activation in IBD patients. Depletion of CD71+ erythroid cells in an allogeneic pregnancy model resulted in upregulation of TLRs, IL-6, and CXCL-1, and enhanced production of TNF-α, in intestinal tissues. In contrast, TGF-β gene expression was reduced. Excessive inflammatory response in the gut [e.g. TNF-α] affects intestinal integrity and CD71+ erythroid cells impact on the gut's bacterial composition.

CONCLUSIONS

Reduced frequency and/or impaired functionality of CD71+ erythroid cells during pregnancy may predispose IBD patients to a more pro-inflammatory milieu in their gastrointestinal tract, characterised by lower Tregs, higher IL-6, and TNF-α, and dysbiosis.

The intestinal microbiota in the pathogenesis of inflammatory bowel diseases: new insights into complex disease

Inflammatory bowel diseases (IBD) are a group of chronic diseases of increasing worldwide prevalence characterized by gastrointestinal (GI) inflammation leading to debilitating symptoms and complications. The contribution of the intestinal microbiota to the pathogenesis and etiology of these diseases is an area of active research interest. Here, we discuss key mechanisms underlying the chronic inflammation seen in IBD as well as evidence implicating the intestinal microbiota in the development and potentiation of that inflammation. We also discuss recently published work in areas of interest within the field of microbial involvement in IBD pathogenesis - the importance of proper microecology within the GI tract, the evidence that the intestinal microbiota transduces environmental and genetic risk factors for IBD, and the mechanisms by which microbial products contribute to communication between microbe and host. There is an extensive body of published research on the evidence for microbial involvement in IBD; the goal of this review is to highlight the growing edges of the field where exciting and innovative research is pushing the boundaries of the conceptual framework of the role of the intestinal microbiota in IBD pathogenesis.

Epithelial MHC Class II Expression and Its Role in Antigen Presentation in the Gastrointestinal and Respiratory Tracts

As the primary barrier between an organism and its environment, epithelial cells are well-positioned to regulate tolerance while preserving immunity against pathogens. Class II major histocompatibility complex molecules (MHC class II) are highly expressed on the surface of epithelial cells (ECs) in both the lung and intestine, although the functional consequences of this expression are not fully understood. Here, we summarize current information regarding the interactions that regulate the expression of EC MHC class II in health and disease. We then evaluate the potential role of EC as non-professional antigen presenting cells. Finally, we explore future areas of study and the potential contribution of epithelial surfaces to gut-lung crosstalk.

Genome-wide association studies of inflammatory bowel disease in German shepherd dogs

Canine Inflammatory Bowel Disease (IBD) is considered a multifactorial disease caused by complex interactions between the intestinal immune system, intestinal microbiota and environmental factors in genetically susceptible individuals. Although IBD can affect any breed, German shepherd dogs (GSD) in the UK are at increased risk of developing the disease. Based on previous evidence, the aim of the present study was to identify single nucleotide polymorphisms (SNPs), which may confer genetic susceptibility or resistance to IBD using a genome-wide association study (GWAS). Genomic DNA was extracted from EDTA blood or saliva samples of 96 cases and 98 controls. Genotyping of cases and controls was performed on the Canine Illumina HD SNP array and data generated was analyzed using PLINK. Several SNPs and regions on chromosomes 7,9,11 and 13 were detected to be associated with IBD using different SNP-by-SNP association methods and FST windows approach. Searching one Mb up-and down-stream of the most significant SNPs, as identified by single SNP analysis as well as 200Kb before and after the start and the end position of the associated regions identified by FST windows approach, we identified 63 genes. Using a combination of pathways analysis and a list of genes that have been reported to be involved in human IBD, we identified 16 candidate genes potentially associated with IBD in GSD.

Pregnancy-Onset Inflammatory Bowel Disease: A Subtle Diagnosis

BACKGROUND

Inflammatory bowel diseases (IBDs) are commonly diagnosed during the reproductive years. IBD first manifested during pregnancy (pregnancy-onset IBD [POIBD]) is still an undescribed entity. The aim of the study was to evaluate the characteristics and maternal and neonatal outcomes of patients with POIBD.

METHODS

Data of all pregnant women with IBD within a single multidisciplinary referral clinic, IBD-MOM, between 2011-2016, were analyzed. Maternal and neonatal characteristics and outcomes were compared between the POIBD group and those diagnosed before pregnancy (non-POIBD).

RESULTS

We identified 237 women, 31 (15%) from the POIBD group and 206 (85%) from the non-POIBD group. Eight (3.5%) patients experienced early spontaneous pregnancy loss, all in the non-POIBD group. The POIBD diagnosis occurred in 16 (52%) patients during the first trimester, 10 (32%) in second trimester, and 5 (16%) during third trimester. Diagnosis of ulcerative colitis (UC) was significantly more common in the POIBD group compared with the non-POIBD group (22/31, 71% vs 50/206, 24%, respectively, P < 0.001). More UC than Crohn's disease patients had active disease during pregnancy (69% vs 50%, P = 0.03, respectively). POIBD patients experienced vaginal delivery in 100% of births, compared with 164 (79.6%) in the non-POIBD group (P = 0.017). The mean gestational age at birth and the neonatal weight were similar among the study groups; 38.6 weeks and 3040 g for POIBD patients, compared with 38.7 weeks and 3055 g in the non-POIBD group.

CONCLUSIONS

POIBD is a unique clinical entity, and the diagnosis is mostly UC. However, the maternal and neonatal outcomes are similar.

Interleukin-4 and Interleukin-10 Gene Polymorphisms in Patients with Inflammatory Bowel Disease

BACKGROUND

Changes in cytokine expression have been frequently found in patients with inflammatory bowel disease (IBD). Cytokine values outside the normal range may be somewhat related to common polymorphisms within cytokine genes.

OBJECTIVE

The present study was designed to investigate the possible association between polymorphisms within Interleukin IL-4 and IL-10 genes and susceptibility to and clinical features of IBD.

METHODS

The study population was composed of 140 healthy controls and 75 patients with IBD (40 patients with Crohn's disease (CD) and 35 patients with ulcerative colitis (UC)). Genotyping was performed using polymerase chain reaction with sequence-specific primers.

RESULTS

Higher frequencies for the C allele of IL-4-590 polymorphism (P < 0.0001; odds ratio [OR], 5.68; 95% confidence interval [95% CI], 3.28-9.83) and for the T allele of IL-4-1098 polymorphism (P = 0.016; OR, 1.83; 95% CI, 1.11-3.02) were observed in the whole group of IBD patients. The IL-4-590 C allele was also significantly overrepresented when IBD patients were subdivided into CD and UC (P < 0.0001; OR, 5.2-6.28). While the IL-4-1098 T allele was present at higher frequencies in patients with UC (P = 0.05; OR, 1.95), but not in CD (P = 0.09). Multiple pairwise comparisons indicated that genotypes of all polymorphisms investigated within IL-4 gene are correlated with IBD, CD, and UC. Haplotype analysis showed that the IL-4-1098/-590 TC haplotype might predispose individuals to IBD, CD, and UC whereas the IL-4-1098/-590 TT and GC haplotypes have a protective effect. On the contrary, neither allele nor genotype frequencies of IL-10 polymorphisms (IL-10-1082 A > G, IL-10-592 A > C, and IL-10-819 T > C) were associated with IBD, CD, or UC.

CONCLUSIONS

The present study suggests that IL-4 polymorphisms might play a role in susceptibility to IBD and its major subtypes in the Iranian population.

Differential Contribution of Adhesion Molecules to Th1 and Th2 Cell-Mediated Lung and Bowel Inflammation

CD4⁺ T cells play a critical role in the development of allergic inflammation in several target organs. Various adhesion molecules are involved in the local recruitment of T cells and other inflammatory cells. We investigated the differential contribution of adhesion molecules to T helper 1 (Th1) and Th2 cell-mediated allergic lung and bowel inflammation by employing their neutralizing antibodies. BALB/c mice transferred with in vitro-differentiated antigen-specific Th1 and Th2 cells were intratracheally or intrarectally challenged with a relevant antigen. Infiltration of infused T cells occurred, along with the accumulation of neutrophils and eosinophils in the lungs of Th1 and Th2 cell-transferred recipients, respectively. Th1-mediated neutrophil and Th2-mediated eosinophil accumulation in the large intestine, which occurred after intrarectal challenge with the antigen, was indicated by the significant elevation of myeloperoxidase (MPO) and eosinophil peroxidase (EPO) activity. Blocking experiments with neutralizing antibodies indicated that intercellular cell adhesion molecule (ICAM)-1; vascular cell adhesion molecule (VCAM)-1; and αL, β2, and β7 integrins participate in the accumulation of Th2 cells and eosinophils in the lungs. In contrast, the migration of Th1 cells and neutrophils was diminished by blockage of αL/β2-integrin and ICAM-1, respectively. Mucosal addressin cell adhesion molecule (MadCAM)-1, vascular cell adhesion molecule (VCAM)-1, α4, β1, and β7 contributed to Th1-mediated neutrophilic inflammation in the bowel, though only MadCAM-1, α4, αL, and β2 were involved in Th2-mediated eosinophilic inflammation. We conclude that distinct sets of adhesion molecules are involved in Th1- and Th2-mediated allergic lung and bowel inflammation.

Effector T Helper Cell Subsets in Inflammatory Bowel Diseases

The gastrointestinal tract is a site of high immune challenge, as it must maintain a delicate balance between tolerating luminal contents and generating an immune response toward pathogens. CD4⁺ T cells are key in mediating the host protective and homeostatic responses. Yet, CD4⁺ T cells are also known to be the main drivers of inflammatory bowel disease (IBD) when this balance is perturbed. Many subsets of CD4⁺ T cells have been identified as players in perpetuating chronic intestinal inflammation. Over the last few decades, understanding of how each subset of Th cells plays a role has dramatically increased. Simultaneously, this has allowed development of therapeutic innovation targeting specific molecules rather than broad immunosuppressive agents. Here, we review the emerging evidence of how each subset functions in promoting and sustaining the chronic inflammation that characterizes IBD.

Cannabinoid Receptor 2 Functional Variant Contributes to the Risk for Pediatric Inflammatory Bowel Disease

GOALS

We conducted a case-control association analysis to establish the role of a common CB2 functional variant, Q63R, in the susceptibility to inflammatory bowel disease (IBD).

BACKGROUND

Endocannabinoids may limit intestinal inflammation through cannabinoid receptor 1 and/or 2 (CB1, CB2).

STUDY

We genotyped 217 pediatric IBD patients [112 Crohn's disease (CD), 105 ulcerative colitis (UC)] and 600 controls for the CB2-Q63R variant by Taqman assay. Data were collected from clinical records on age at diagnosis, disease activity, duration and location, extraintestinal manifestations, therapy, clinical relapses, and need for surgery.

RESULTS

We found a significant association of the CB2-R63 variant with IBD (allele frequencies, P=0.04; genotype distributions, P=0.0006), in particular with CD (allele frequencies, P=0.002; genotype distributions, P=0.00005) and with UC only for genotype distributions (P=0.03). RR carriers showed an increased risk for developing IBD [odds ratio (OR)=1.82; P=0.0002 for IBD; OR=2.02; P=10 for CD; OR=1.63; P=0.02 for UC at 95% confidence interval]. Upon genotype-phenotype evaluation, RR patients showed an increased frequency of moderate-to-severe disease activity at diagnosis in the case of both CD and UC (P=0.01 and P=0.02, respectively) and also an earlier clinical relapse in UC (P=0.04). In UC, all the clinical features related to the CB2 risk allele were still significantly associated with the variant when analyzed using a multivariate logistic regression model (P=0.001).

CONCLUSIONS

The CB2-Q63R variant contributes to the risk for pediatric IBD, in particular CD. The R63 variant is associated with a more severe phenotype in both UC and CD. Taken together, our data point toward the involvement of the CB2 receptor in the pathogenesis and clinical features of pediatric IBD.

The colonic epithelium plays an active role in promoting colitis by shaping the tissue cytokine profile

Inflammatory bowel disease (IBD) is a chronic condition driven by loss of homeostasis between the mucosal immune system, the commensal gut microbiota, and the intestinal epithelium. Our goal is to understand how these components of the intestinal ecosystem cooperate to control homeostasis. By combining quantitative measures of epithelial hyperplasia and immune infiltration with multivariate analysis of inter- and intracellular signaling, we identified epithelial mammalian target of rapamycin (mTOR) signaling as a potential driver of inflammation in a mouse model of colitis. A kinetic analysis of mTOR inhibition revealed that the pathway regulates epithelial differentiation, which in turn controls the cytokine milieu of the colon. Consistent with our in vivo analysis, we found that cytokine expression of organoids grown ex vivo, in the absence of bacteria and immune cells, was dependent on differentiation state. Our study suggests that proper differentiation of epithelial cells is an important feature of colonic homeostasis because of its effect on the secretion of inflammatory cytokines.

Genome-wide association studies in Crohn's disease: Past, present and future

Over the course of the past decade, genome-wide association studies (GWAS) have revolutionised our understanding of complex disease genetics. One of the diseases that has benefitted most from this technology has been Crohn's disease (CD), with the identification of autophagy, the IL-17/IL-23 axis and innate lymphoid cells as key players in CD pathogenesis. Our increasing understanding of the genetic architecture of CD has also highlighted how a failure to suppress aberrant immune responses may contribute to disease development - a realisation that is now being incorporated into the design of new treatments. However, despite these successes, a significant proportion of disease heritability remains unexplained. Similarly, most of the causal variants at associated loci have not yet been identified, and even fewer have been functionally characterised. Because of the inarguable rise in the incidence of CD in regions of the world that previously had low disease rates, GWAS studies will soon have to shift from a largely Caucasian focus to include populations from other ethnic backgrounds. Future studies should also move beyond conventional studies of disease susceptibility into phenotypically driven 'within-cases' analyses in order to explore the role of genetics in other important aspects of disease biology. These studies are likely to include assessments of prognosis and/or response to treatments and may be critical if personalised medicine is ever to become a reality.

Altered calcium influx of peripheral Th2 cells in pediatric Crohn's disease: infliximab may normalize activation patterns

Objective

Crohn's disease is a chronic inflammation of the gastrointestinal tract with an abnormal immune phenotype. We investigated how intracellular calcium kinetics of Th1 and Th2 lymphocytes alter upon specific inhibition of Kv1.3 and IKCa1 channels in pediatric Crohn's disease.

Study design

Blood was taken from 12 healthy and 29 Crohn's disease children. Of those, 6 were switched to infliximab and re-sampled after the 4th infliximab treatment. Intracellular calcium levels were monitored using flow cytometry in the presence or absence of specific inhibitors of Kv1.3 and IKCa1 potassium channels.

Results

In Crohn's disease treated with standard therapy, calcium response during activation was higher than normal in Th2 cells. This was normalized in vitro by inhibition of Kv1.3 or IKCa1 potassium channels. After the switch to infliximab, potassium channel function and expression in Th2 lymphocytes were comparable to those in Th1 cells.

Conclusion

These results may indicate that potassium channels are potential immune modulatory targets in Crohn's disease.

Higher serum vitamin D levels are associated with protective serum cytokine profiles in patients with ulcerative colitis

BACKGROUND & AIMS

Vitamin D has immune modulating effects on cytokines. Serum vitamin D levels are associated with the risk of relapse in patients with ulcerative colitis (UC), through unknown mechanisms. We tested the hypothesis that this beneficial role of vitamin D on UC is mediated through anti-inflammatory serum cytokine profiles.

METHODS

Serum samples from a prospective cohort of seventy UC patients in clinical remission were collected and baseline histological and endoscopic scores were recorded at enrollment. Clinical relapse events were recorded over the 12-month follow-up period. Serum vitamin D and cytokines levels (IL-6, IL-8, IL-17A, TNF-α, IFN-γ, IL-4, IL-10) were quantified using ELISA. Linear regression was used to determine correlation between vitamin D and cytokine profiles. Logistic regression models were used to determine the association between serum cytokine profiles and baseline histologic mucosal healing and clinical relapse.

RESULTS

Higher serum vitamin D levels positively correlated with higher ratios of IL-4 + IL-10/IL-17A + TNF-α (r = 0.37, P < .01), and IL-4 + IL-10/IL-6 + TNF-α (r = 0.32, P < .01). In multivariate analysis, IL-4 + IL-10/IL-17A + TNF-α ratios at baseline were associated with the presence of histologic mucosal healing (O.R. 1.29, 95% CI 1.02-1.62, P = .03). A higher ratio of serum IL-4 + IL-10 to IL-6 + TNF-α was associated with a reduced risk of clinical relapse (O.R. 0.72, 95% CI 0.58-0.89, P = .003), and longer time to relapse (p = .03), over the 12-month follow-up period. This ratio during remission had an AUC of 0.7 in predicting later clinical relapse.

CONCLUSIONS

Vitamin D is associated with anti-inflammatory serum cytokine profiles. Anti-inflammatory cytokine patterns may mediate the protective effects of higher serum vitamin D levels in patients with ulcerative colitis.

Triterpenoid herbal saponins enhance beneficial bacteria, decrease sulfate-reducing bacteria, modulate inflammatory intestinal microenvironment and exert cancer preventive effects in ApcMin/+ mice

Saponins derived from medicinal plants have raised considerable interest for their preventive roles in various diseases. Here, we investigated the impacts of triterpenoid saponins isolated from Gynostemma pentaphyllum (GpS) on gut microbiome, mucosal environment, and the preventive effect on tumor growth. Six-week old ApcMin/+ mice and their wild-type littermates were fed either with vehicle or GpS daily for the duration of 8 weeks. The fecal microbiome was analyzed by enterobacterial repetitive intergenic consensus (ERIC)-PCR and 16S rRNA gene pyrosequencing. Study showed that GpS treatment significantly reduced the number of intestinal polyps in a preventive mode. More importantly, GpS feeding strikingly reduced the sulfate-reducing bacteria lineage, which are known to produce hydrogen sulfide and contribute to damage the intestinal epithelium or even promote cancer progression. Meanwhile, GpS also boosted the beneficial microbes. In the gut barrier of the ApcMin/+ mice, GpS treatment increased Paneth and goblet cells, up-regulated E-cadherin and down-regulated N-cadherin. In addition, GpS decreased the pro-oncogenic β-catenin, p-Src and the p-STAT3. Furthermore, GpS might also improve the inflamed gut epithelium of the ApcMin/+ mice by upregulating the anti-inflammatory cytokine IL-4, while downregulating pro-inflammatory cytokines TNF-α, IL-1β and IL-18. Intriguingly, GpS markedly stimulated M2 and suppressed M1 macrophage markers, indicating that GpS altered mucosal cytokine profile in favor of the M1 to M2 macrophages switching, facilitating intestinal tissue repair. In conclusion, GpS might reverse the host's inflammatory phenotype by increasing beneficial bacteria, decreasing sulfate-reducing bacteria, and alleviating intestinal inflammatory gut environment, which might contribute to its cancer preventive effects.

Comparison of Cytokine and Efflux Transporter Expression in Pediatric Versus Adult-onset Ulcerative Colitis

OBJECTIVES

Ulcerative colitis (UC), a chronic inflammation of the colon, is often more severe in children than adults. Identification of altered expression of efflux transporters, cytokines, and suppressor of cytokine signaling (SOCS) molecules in pediatric versus adult patients could provide insight into the differential molecular patterns related to the age and disease pathology.

METHODS

Mucosal samples from terminal ileum and colon in pediatric (9 UC-New, 4 UC-Remission) and adult (9 UC-New, 8 UC-Remission) patients were compared with healthy subjects (15 children and 10 adults) for mRNA expressions of several efflux transporters, cytokines, and SOCS molecules.

RESULTS

The inflamed colon interleukin (IL)-6, IL-17A, and interferon-γ levels were elevated in UC-New subgroups but close to control values in UC-Remission. IL-1β expression was increased only in UC-New children. Interestingly, uninflamed ileum also showed increased IL-6 and IL-1β levels in UC-New subgroups. SOCS1/SOCS3 expression pattern followed a trend observed for inflammatory cytokines only in children. Both children and adults had decreased multidrug resistance protein 1 expression in colon, which inversely correlated with disease score, IL-6 and interferon-γ levels in UC-New children. IL-2 expression was upregulated in UC-Remission, compared with controls.

CONCLUSIONS

Efflux transporter expression varies between UC children and adults except for decreased multidrug resistance protein 1. UC is characterized by a dysregulated TH1 and TH17 cytokine response irrespective of age at disease onset, with higher cytokine levels detected in children. Increased IL-2 levels in remission imply a protective role for regulatory T cells (Tregs).

Helminth Regulation of Immunity: A Three-pronged Approach to Treat Colitis

By reputation, the parasite is a pariah, an unwelcome guest. Infection with helminth parasites evokes stereotypic immune responses in humans and mice that are dominated by T helper (Th)-2 responses; thus, a hypothesis arises that infection with helminths would limit immunopathology in concomitant inflammatory disease. Although infection with some species of helminths can cause devastating disease and affect the course of microbial infections, analyses of rodent models of inflammatory disease reveal that infection with helminth parasites, or treatment with helminth extracts, can limit the severity of autoinflammatory disease, including colitis. Intriguing, but fewer, studies show that adoptive transfer of myeloid immune cells treated with helminth products/extracts in vitro can suppress inflammation. Herein, 3 facets of helminth therapy are reviewed and critiqued: treatment with viable ova or larvae, treatment with crude extracts of the worm or purified molecules, and cellular immunotherapy. The beneficial effect of helminth therapy often converges on the mobilization of IL-10 and regulatory/alternatively activated macrophages, while there are reports on transforming growth factor (TGF)-β, regulatory T cells and dendritic cells, and recent data suggest that helminth-evoked changes in the microbiota should be considered when defining anticolitic mechanisms. We speculate that if the data from animal models translate to humans, noting the heterogeneity therein, then the choice between use of viable helminth ova, helminth extracts/molecules or antigen-pulsed immune cells could be matched to disease management in defined cohorts of patients with inflammatory bowel disease.

Crosstalk between Inflammation and ROCK/MLCK Signaling Pathways in Gastrointestinal Disorders with Intestinal Hyperpermeability

The barrier function of the intestine is essential for maintaining the normal homeostasis of the gut and mucosal immune system. Abnormalities in intestinal barrier function expressed by increased intestinal permeability have long been observed in various gastrointestinal disorders such as Crohn's disease (CD), ulcerative colitis (UC), celiac disease, and irritable bowel syndrome (IBS). Imbalance of metabolizing junction proteins and mucosal inflammation contributes to intestinal hyperpermeability. Emerging studies exploring in vitro and in vivo model system demonstrate that Rho-associated coiled-coil containing protein kinase- (ROCK-) and myosin light chain kinase- (MLCK-) mediated pathways are involved in the regulation of intestinal permeability. With this perspective, we aim to summarize the current state of knowledge regarding the role of inflammation and ROCK-/MLCK-mediated pathways leading to intestinal hyperpermeability in gastrointestinal disorders. In the near future, it may be possible to specifically target these specific pathways to develop novel therapies for gastrointestinal disorders associated with increased gut permeability.

Regional Specialisation of T Cell Subsets and Apoptosis in the Human Gut Mucosa: Differences Between Ileum and Colon in Healthy Intestine and Inflammatory Bowel Diseases

BACKGROUND AND AIMS

There is very limited information regarding region-specific immunological response in human intestine. We aimed to determine differences in immune compartmentalisation between ileum and colon in healthy and inflamed mucosa.

METHODS

T cell profile and its apoptosis were measured by flow cytometry, Th1, Th17, Treg [CD4(+)CD25(+)FOXP3(+)], double positive [DP, CD3(+)CD4(+)CD8(+)] and double negative T cells [DN, CD3(+)CD4(-)CD8(-)], immunohistochemistry [FOXP3, caspase-3], and real-time polymerase chain reaction [PCR] [IFN-γ, IL-17-A, and FOXP3] on biopsies from different regions of healthy intestine and of intestine in inflammatory bowel diseases.

RESULTS

Healthy colon showed higher percentages of Treg, Th17, and DN, and lower numbers of DP T cells compared with ileum [p < 0.05]. Some but not all region-specific differences were lost in inflammatory conditions. Disease-specific patterns were found: a Th1/Th17 pattern and a Th17 pattern in Crohn's disease and ulcerative colitis respectively, whereas a reduction in Th1/Th17 was found in microscopic colitis. In colonic Crohn's disease and microscopic colitis, DN T cells had a pattern inverse to that of Th1/Th17 (increase in microscopic colitis [p < 0.05] and decrease in Crohn's disease [p < 0.005]). Higher levels of lymphocyte apoptosis were found in healthy colon compared with the ileal counterparts [p = 0.001]. All forms of colonic inflammation presented a dramatic decrease in apoptosis compared with healthy colon. By contrast ileal Crohn's disease showed higher levels of cleaved-Caspase(+) CD3(+) cells.

CONCLUSIONS

Immunological differences exist in healthy gastrointestinal tract. Inflammatory processes overwhelm some location-specific differences, whereas others are maintained. Care has to be taken when analysing immune response in intestinal inflammation, as location-specific differences may be relevant.

Regulation of antiapoptotic and cytoprotective pathways in colonic epithelial cells in ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease involving the colon resulting in bloody diarrhea and increased risk of colorectal cancer in certain patient subgroups. Increased apoptosis in the epithelial cell layer causes increased permeability, especially during flares; this leads to translocation of luminal pathogens resulting in a continued inflammatory drive. The present work investigates how epithelial apoptosis is regulated in ulcerative colitis. The main results are that Fas mediated apoptosis is inhibited during flares of ulcerative colitis, probably by an upregulation of cellular inhibitor of apoptosis protein 2 (cIAP2) and cellular FLICE-like inhibitory protein. cIAP2 is upregulated in regenerative epithelial cells both in ulcerative colitis and in experimental intestinal wounds. Inhibition of cIAP2 decreases wound healing in vitro possibly through inhibition of migration. Altogether, it is shown that epithelial cells in ulcerative colitis responds to the hostile microenvironment by activation of cytoprotective pathways that tend to counteract the cytotoxic effects of inflammation. However, the present studies also show that epithelial cells produce increased amounts of reactive oxygen species during stimulation with tumor necrosis factor-α and interferon-γ resulting in DNA instability. The combined effect of increased DNA-instability and decreased apoptosis responses could lead to neoplasia.

Mucosal Interactions between Genetics, Diet, and Microbiome in Inflammatory Bowel Disease

Numerous reviews have discussed gut microbiota composition changes during inflammatory bowel diseases (IBD), particularly Crohn’s disease (CD). However, most studies address the observed effects by focusing on studying the univariate connection between disease and dietary-induced alterations to gut microbiota composition. The possibility that these effects may reflect a number of other interconnected (i.e., pantropic) mechanisms, activated in parallel, particularly concerning various bacterial metabolites, is in the process of being elucidated. Progress seems, however, hampered by various difficult-to-study factors interacting at the mucosal level. Here, we highlight some of such factors that merit consideration, namely: (1) the contribution of host genetics and diet in altering gut microbiome, and in turn, the crosstalk among secondary metabolic pathways; (2) the interdependence between the amount of dietary fat, the fatty acid composition, the effects of timing and route of administration on gut microbiota community, and the impact of microbiota-derived fatty acids; (3) the effect of diet on bile acid composition, and the modulator role of bile acids on the gut microbiota; (4) the impact of endogenous and exogenous intestinal micronutrients and metabolites; and (5) the need to consider food associated toxins and chemicals, which can introduce confounding immune modulating elements (e.g., antioxidant and phytochemicals in oils and proteins). These concepts, which are not mutually exclusive, are herein illustrated paying special emphasis on physiologically inter-related processes.

Cytokine Networks and T-Cell Subsets in Inflammatory Bowel Diseases

Pathogenesis of the inflammatory bowel diseases (IBDs), such as ulcerative colitis (UC) and Crohn's disease (CD), involve proinflammatory changes within the microbiota, chronic immune-mediated inflammatory responses, and epithelial dysfunction. Converging data from genome-wide association studies, mouse models of IBD, and clinical trials indicate that cytokines are key effectors of both normal homeostasis and chronic inflammation in the gut. Yet many questions remain concerning the role of specific cytokines in different IBDs within distinct regions of the gut, and regarding cellular mechanisms of action. In this article, we review current and emerging concepts concerning the role of cytokines in IBD with a focus on immune regulation, T cell subsets, and potential clinical applications.