Defects in mucosal immunity leading to Crohn's disease

The role of bacteriophage in inflammatory bowel disease and its therapeutic potential

Inflammatory bowel disease (IBD) refers to a group of chronic inflammatory disorders impacting the gastrointestinal (GI) tract. It represents a significant public health challenge due to its rising global incidence and substantial impact on patients' quality of life. Emerging research suggests a pivotal role of the human microbiome in IBD pathogenesis. Bacteriophages, integral components of the human microbiome, are indicated to influence the disease onset, progression, and therapeutic strategies. Here, we review the effect of bacteriophages on the pathogenesis of IBD and, more specifically, on the gut bacteria, the systemic immunity, and the susceptibility genes. Additionally, we explore the potential therapeutic use of the bacteriophages to modify gut microbiota and improve the health outcomes of IBD patients. This review highlights the potential of therapeutic bacteriophages in regulating gut microbiota and modulating the immune response to improve health outcomes in IBD patients. Future studies on personalized bacteriophage therapy and its integration into clinical practice could advance treatment strategies for IBD.

Interplay between creeping fat and gut microbiota: A brand-new perspective on fecal microbiota transplantation in Crohn's disease

Inflammatory bowel disease, particularly Crohn's disease (CD), has been linked to modifications in mesenteric adipose tissue (MAT) and the phenomenon known as "creeping fat" (CrF). The presence of CrF is believed to serve as a predictor for early clinical recurrence following surgical intervention in patients with CD. Notably, the incorporation of the mesentery during ileocolic resection for CD has been correlated with a decrease in surgical recurrence, indicating the significant role of MAT in the pathogenesis of CD. While numerous studies have indicated that dysbiosis of the gut microbiota is a critical factor in the development of CD, the functional implications of translocated microbiota within the MAT of CD patients remain ambiguous. This manuscript commentary discusses a recent basic research conducted by Wu et al. In their study, intestinal bacteria from individuals were transplanted into CD model mice, revealing that fecal microbiota transplantation (FMT) from healthy donors alleviated CD symptoms, whereas FMT from CD patients exacerbated these symptoms. Importantly, FMT was found to affect intestinal permeability, barrier function, and the levels of proinflammatory factors and adipokines. Collectively, these findings suggest that targeting MAT and CrF may hold therapeutic potential for patients with CD. However, the study did not evaluate the composition of the intestinal microbiota of the donors or the subsequent alterations in the gut microbiota. Overall, the gut microbiota plays a crucial role in the histopathology of CD, and thus, targeting MAT and CrF may represent a promising avenue for treatment in this patient population.

Opportunities and challenges in the therapeutic exploitation of histamine and histamine receptor pharmacology in inflammation-driven disorders

Inflammation-driven diseases encompass a wide array of pathological conditions characterised by immune system dysregulation leading to tissue damage and dysfunction. Among the myriad of mediators involved in the regulation of inflammation, histamine has emerged as a key modulatory player. Histamine elicits its actions through four rhodopsin-like G-protein-coupled receptors (GPCRs), named chronologically in order of discovery as histamine H1, H2, H3 and H4 receptors (H1-4R). The relatively low affinity H1R and H2R play pivotal roles in mediating allergic inflammation and gastric acid secretion, respectively, whereas the high affinity H3R and H4R are primarily linked to neurotransmission and immunomodulation, respectively. Importantly, however, besides the H4R, both H1R and H2R are also crucial in driving immune responses, the H2R tending to promote yet ill-defined and unexploited suppressive, protective and/or resolving processes. The modulatory action of histamine via its receptors on inflammatory cells is described in detail. The potential therapeutic value of the most recently discovered H4R in inflammatory disorders is illustrated via a selection of preclinical models. The clinical trials with antagonists of this receptor are discussed and possible reasons for their lack of success described.

Exploring the role of IL-1β in inflammatory bowel disease pathogenesis

Interleukin 1β (IL-1β) is a significant mediator of inflammation and tissue damage in IBD. The balance between IL-1β and its endogenous inhibitor-IL-1Ra-, plays a critical role in both initiation and regulation of inflammation. However, the precise role of IL-1β as a causative factor in IBD or simply a consequence of inflammation remains unclear. This review summarizes current knowledge on the molecular and cellular characteristics of IL-1β, describes the existing evidence on the role of this cytokine as a modulator of intestinal homeostasis and an activator of inflammatory responses, and also discusses the role of microRNAs in the regulation of IL-1β-related inflammatory responses in IBD. Current evidence indicates that IL-1β is involved in several aspects during IBD as it greatly contributes to the induction of pro-inflammatory responses through the recruitment and activation of immune cells to the gut mucosa. In parallel, IL-1β is involved in the intestinal barrier disruption and modulates the differentiation and function of T helper (Th) cells by activating the Th17 cell differentiation, known to be involved in the pathogenesis of IBD. Dysbiosis in the gut can also stimulate immune cells to release IL-1β, which, in turn, promotes inflammation. Lastly, increasing evidence pinpoints the central role of miRNAs involvement in IL-1β-related signaling during IBD, particularly in the maintenance of homeostasis within the intestinal epithelium. In conclusion, given the crucial role of IL-1β in the promotion of inflammation and immune responses in IBD, the targeting of this cytokine or its receptors represents a promising therapeutic approach. Further research into the IL-1β-associated post-transcriptional modifications may elucidate the intricate role of this cytokine in immunomodulation.

Gut-brain axis interacts with immunomodulation in inflammatory bowel disease

The brain and the gastrointestinal (GI) tract are important sensory organs in the body and the two-way interaction that exists between them regulates key physiological and homeostatic functions. A growing body of research suggests that this bidirectional communication influences the development and progression of functional GI disorders and plays an important role in the treatment of central nervous system (CNS) disorders. Inflammatory bowel disease (IBD) is a classic intestinal disorder with a high prevalence but still unclear pathogenesis that has been widely discussed in recent years. However, in the studies available to date, we find that many authors have chosen to discuss the influence of the brain on intestinal disorders from the top down, starting with physical and psychological disorders. Coming very naturally, based on these substantial research evidence, we focus on exploring the links between bidirectional communication in the gut-brain axis and IBD, and highlight the role of the gut microbiota, vagus nerve (VN), receptors and immune cells involved in regulating IBD through the gut-brain axis in this review.

FMT rescues mice from DSS-induced colitis in a STING-dependent manner

Fecal microbiota transplantation (FMT) is currently a promising therapy for inflammatory bowel disease (IBD). However, clinical studies have shown that there is an obvious individual difference in the efficacy of FMT. Therefore, it is a pressing issue to identify the factors that influence the efficacy of FMT and find ways to screen the most suitable patients for this therapy. In this work, we targeted the stimulator of interferon genes (STING), a DNA-sensing protein that regulates host-defense. By comparing the differential efficacy of FMT in mice with different expression level of STING, it is revealed that FMT therapy provides treatment for DSS-induced colitis in a STING-dependent manner. Mechanistically, FMT exerts a regulatory effect on the differentiation of intestinal Th17 cells and macrophages, splenic Th1 and Th2 cells, as well as Th1 cells of the mesenteric lymph nodes via STING, down-regulating the colonic M1/M2 and splenic Th1/Th2 cell ratios, thereby improving the imbalanced immune homeostasis in the inflamed intestine. Meanwhile, based on the 16SrDNA sequencing of mice fecal samples, STING was found to facilitate the donor strain colonization in recipients' gut, mainly Lactobacillales, thereby reshaping the gut microbiota disturbed by colitis. Consequently, we proposed that STING, as a key target of FMT therapy, is potentially a biomarker for screening the most suitable individuals for FMT to optimize treatment regimens and enhance clinical benefit.

Biological functions of connexins in the development of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of chronic intestinal inflammatory diseases with unknown etiology. Gap junctions composed of connexins (Cxs) have been recently validated as an important factor in the development of IBD. Under IBD-induced inflammatory response in the gut, gap junctions connect multiple signaling pathways involved in the interaction between inflammatory cells with other intestinal cells, which altogether mediate the development of IBD. This paper is a narrative review aiming to comprehensively elucidate the biological function of connexins, especially the ubiquitously and predominantly expressed Cx43, in the pathogenesis of IBD.

Selected Cytokines and Metalloproteinases in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a collective term for two diseases: ulcerative colitis (UC) and Crohn's disease (CD). There are many factors, e.g., genetic, environmental and immunological, that increase the likelihood of these diseases. Indicators of IBDs include extracellular matrix metalloproteinases (MMPs). The aim of this review is to present data on the role of selected cytokines and metalloproteinases in IBD. In recent years, more and more transcriptomic studies are emerging. These studies are improving the characterization of the cytokine microenvironment inside inflamed tissue. It is observed that the levels of several cytokines are consistently increased in inflamed tissue in IBD, both in UC and CD. This review shows that MMPs play a major role in the pathology of inflammatory processes, cancer, and IBD. IBD-associated inflammation is associated with increased expression of MMPs and reduced ability of tissue inhibitors of metalloproteinases (TIMPs) to inhibit their action. In IBD patients in tissues that are inflamed, MMPs are produced in excess and TIMP activity is not sufficient to block MMPs. This review is based on our personal selection of the literature that was retrieved by a selective search in PubMed using the terms "Inflammatory bowel disease" and "pathogenesis of Inflammatory bowel diseases" that includes systematic reviews, meta-analyses, and clinical trials. The involvement of the immune system in the pathophysiology of IBD is reviewed in terms of the role of the cytokines and metalloproteinases involved.

Recent Advances in Cell-Based In Vitro Models to Recreate Human Intestinal Inflammation

Inflammatory bowel disease causes a major burden to patients and healthcare systems, raising the need to develop effective therapies. Technological advances in cell culture, allied with ethical issues, have propelled in vitro models as essential tools to study disease aetiology, its progression, and possible therapies. Several cell-based in vitro models of intestinal inflammation have been used, varying in their complexity and methodology to induce inflammation. Immortalized cell lines are extensively used due to their long-term survival, in contrast to primary cultures that are short-lived but patient-specific. Recently, organoids and organ-chips have demonstrated great potential by being physiologically more relevant. This review aims to shed light on the intricate nature of intestinal inflammation and cover recent works that report cell-based in vitro models of human intestinal inflammation, encompassing diverse approaches and outcomes.

Prussian blue nanozymes: progress, challenges, and opportunities

Prussian Blue Nanozymes (PBNZs) have emerged as highly efficient agents for reactive oxygen species (ROS) elimination, owing to their multiple enzyme-like properties encompassing catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) activities. As a functional nanomaterial mimicking enzyme, PBNZs not only surmount the limitations of natural enzymes, such as instability and high manufacturing costs, but also exhibit superior stability, tunable activity, low storage expenses, and remarkable reusability. Consequently, PBNZs have gained significant attention in diverse biomedical applications, including disease diagnosis and therapy. Over the past decade, propelled by advancements in catalysis science, biotechnology, computational science, and nanotechnology, PBNZs have witnessed remarkable progress in the exploration of their enzymatic activities, elucidation of catalytic mechanisms, and wide-ranging applications. This comprehensive review aims to provide a systematic overview of the discovery and catalytic mechanisms of PBNZ, along with the strategies employed to modulate their multiple enzyme-like activities. Furthermore, we extensively survey the recent advancements in utilizing PBNZs for scavenging ROS in various biomedical applications. Lastly, we analyze the existing challenges of translating PBNZs into therapeutic agents for clinical use and outline future research directions in this field. By presenting a comprehensive synopsis of the current state of knowledge, this review seeks to contribute to a deeper understanding of the immense potential of PBNZs as an innovative therapeutic agent in biomedicine.

Intestinal Immune Imbalance is an Alarm in the Development of IBD

Immune regulation plays a crucial role in human health and disease. Inflammatory bowel disease (IBD) is a chronic relapse bowel disease with an increasing incidence worldwide. Clinical treatments for IBD are limited and inefficient. However, the pathogenesis of immune-mediated IBD remains unclear. This review describes the activation of innate and adaptive immune functions by intestinal immune cells to regulate intestinal immune balance and maintain intestinal mucosal integrity. Changes in susceptible genes, autophagy, energy metabolism, and other factors interact in a complex manner with the immune system, eventually leading to intestinal immune imbalance and the onset of IBD. These events indicate that intestinal immune imbalance is an alarm for IBD development, further opening new possibilities for the unprecedented development of immunotherapy for IBD.

Immunomodulatory Properties of Natural Extracts and Compounds Derived from Bidens pilosa L.: Literature Review

Bidens pilosa L. has been used in different parts of the world mainly to treat diseases associated with immune response disorders, such as autoimmunity, cancer, allergies, and infectious diseases. The medicinal properties of this plant are attributed to its chemical components. Nevertheless, there is little conclusive evidence that describes the immunomodulatory activity of this plant. In this review, a systematic search was carried out in the PubMed-NLM, EBSCO Host and BVS databases focused on the pre-clinical scientific evidence of the immunomodulatory properties of B. pilosa. A total of 314 articles were found and only 23 were selected. The results show that the compounds or extracts of Bidens modulate the immune cells. This activity was associated with the presence of phenolic compounds and flavonoids that control proliferation, oxidative stress, phagocytosis, and the production of cytokines of different cells. Most of the scientific information analyzed in this paper supports the potential use of B. pilosa mainly as an anti-inflammatory, antioxidant, antitumoral, antidiabetic, and antimicrobial immune response modulator. It is necessary that this biological activity be corroborated through the design of specialized clinical trials that demonstrate the effectiveness in the treatment of autoimmune diseases, chronic inflammation, and infectious diseases. Until now there has only been one clinical trial in phase I and II associated with the anti-inflammatory activity of Bidens in mucositis.

Interplay of broccoli/broccoli sprout bioactives with gut microbiota in reducing inflammation in inflammatory bowel diseases

Inflammatory Bowel Diseases (IBD) are chronic, reoccurring, and debilitating conditions characterized by inflammation in the gastrointestinal tract, some of which can lead to more systemic complications and can include autoimmune dysfunction, a change in the taxonomic and functional structure of microbial communities in the gut, and complicated burdens in a person's daily life. Like many diseases based in chronic inflammation, research on IBD has pointed towards a multifactorial origin involving factors of the person's lifestyle, immune system, associated microbial communities, and environmental conditions. Treatment currently exists only as palliative care, and seeks to disrupt the feedback loop of symptoms by reducing inflammation and allowing as much of a return to homeostasis as possible. Various anti-inflammatory options have been explored, and this review focuses on the use of diet as an alternative means of improving gut health. Specifically, we highlight the connection between the role of sulforaphane from cruciferous vegetables in regulating inflammation and in modifying microbial communities, and to break down the role they play in IBD.

miRNA Molecules-Late Breaking Treatment for Inflammatory Bowel Diseases?

MicroRNAs (miRNAs) are a group of non-coding RNAs that play a critical role in regulating epigenetic mechanisms in inflammation-related diseases. Inflammatory bowel diseases (IBDs), which primarily include ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic recurrent inflammation of intestinal tissues. Due to the multifactorial etiology of these diseases, the development of innovative treatment strategies that can effectively maintain remission and alleviate disease symptoms is a major challenge. In recent years, evidence for the regulatory role of miRNAs in the pathogenetic mechanisms of various diseases, including IBD, has been accumulating. In light of these findings, miRNAs represent potential innovative candidates for therapeutic application in IBD. In this review, we discuss recent findings on the role of miRNAs in regulating inflammatory responses, maintaining intestinal barrier integrity, and developing fibrosis in clinical and experimental IBD. The focus is on the existing literature, indicating potential therapeutic application of miRNAs in both preclinical experimental IBD models and translational data in the context of clinical IBD. To date, a large and diverse data set, which is growing rapidly, supports the potential use of miRNA-based therapies in clinical practice, although many questions remain unanswered.

Molecular Mechanisms Underlying IL-33-Mediated Inflammation in Inflammatory Bowel Disease

Interleukin-33 (IL-33) is a cytokine defined by its pleiotropic function, acting either as a typical extracellular cytokine or as a nuclear transcription factor. IL-33 and its receptor, suppression of tumorigenicity 2 (ST2), interact with both innate and adaptive immunity and are considered critical regulators of inflammatory disorders. The IL-33/ST2 axis is involved in the maintenance of intestinal homeostasis; on the basis of their role as pro- or anti-inflammatory mediators of first-line innate immunity, their expression is of great importance in regard to mucosal defenses. Mucosal immunity commonly presents an imbalance in inflammatory bowel disease (IBD). This review summarizes the main cellular and molecular aspects of IL-33 and ST2, mainly focusing on the current evidence of the pro- and anti-inflammatory effects of the IL-33/ST2 axis in the course of ulcerative colitis and Crohn's disease, as well as the molecular mechanisms underlying the association of IL-33/ST2 signaling in IBD pathogenesis. Although IL-33 modulates and impacts the development, course, and recurrence of the inflammatory response, the exact role of this molecule is elusive, and it seems to be associated with the subtype of the disease or the disease stage. Unraveling of IL-33/ST2-mediated mechanisms involved in IBD pathology shows great potential for clinical application as therapeutic targets in IBD treatment.

Identification of immune infiltration and cuproptosis-related subgroups in Crohn's disease

Background

Crohn's disease (CD) is a type of heterogeneous, dysfunctional immune-mediated intestinal chronic and recurrent inflammation caused by a variety of etiologies. Cuproptosis is a newly discovered form of programmed cell death that seems to contribute to the advancement of a variety of illnesses. Consequently, the major purpose of our research was to examine the role of cuproptosis-related genes in CD.

Methods

We obtained two CD datasets from the gene expression omnibus (GEO) database, and immune cell infiltration was created to investigate immune cell dysregulation in CD. Based on differentially expressed genes (DEGs) and the cuproptosis gene set, differentially expressed genes of cuproptosis (CuDEGs) were found. Then, candidate hub cuproptosis-associated genes were found using machine learning methods. Subsequently, using 437 CD samples, we explored two distinct subclusters based on hub cuproptosis-related genes. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, Gene set variation analysis (GSVA) and immune infiltration analysis studies were also used to assess the distinct roles of the subclusters.

Results

Overall, 25 CuDEGs were identified, including ABCB6, BACE1, FDX1, GLS, LIAS, MT1M, PDHA1, etc. And most CuDEGs were expressed at lower levels in CD samples and were negatively related to immune cell infiltration. Through the machine learning algorithms, a seven gene cuproptosis-signature was identified and two cuproptosis-related subclusters were defined. Cluster-specific differentially expressed genes were found only in one cluster, and functional analysis revealed that they were involved in several immune response processes. And the results of GSVA showed positive significant enrichment in immune-related pathways in cluster A, while positive significant enrichment in metabolic pathways in cluster B. In addition, an immune infiltration study indicated substantial variation in immunity across different groups. Immunological scores were higher and immune infiltration was more prevalent in Cluster A.

Conclusion

According to the current research, the cuproptosis phenomenon occurs in CD and is correlated with immune cell infiltration and metabolic activity. This information indicates that cuproptosis may promote CD progression by inducing immunological response and metabolic dysfunction. This research has opened new avenues for investigating the causes of CD and developing potential therapeutic targets for the disease.

Early life administration of Bifidobacterium bifidum BD-1 alleviates long-term colitis by remodeling the gut microbiota and promoting intestinal barrier development

Inflammatory bowel disease (IBD) is a chronic intestinal disease characterized by microbiota disturbance and intestinal mucosal damage. The current study aimed to investigate the preventive effects of Bifidobacterium bifidum BD-1 (BD-1) against long-term IBD and possible mechanism by which it alters the gut microbiota, immune response, and mucosal barrier. Our study found that early treatment of BD-1 + Ceftri (ceftriaxone followed by BD-1) and BD-1 confers a certain protective effect against the occurrence of long-term Dextran sulfate sodium-induced colitis, which manifests as a decrease in inflammation scores and MPO activity levels, as well as a relatively intact intestinal epithelial structure. Moreover, compared to BD-1, Ceftri, and NS, early treatment with BD-1 + Ceftri promoted greater expression levels of mucosal barrier-related proteins [KI67, MUC2, ZO-1, secretory immunoglobulin A (slgA), Clauding-1, and Occludin], better local immune responses activation, and moderately better modulation of systemic immune responses during long-term colitis. This may be due to the fact that BD-1 + Ceftri can deliberately prolong the colonization time of some beneficial microbiota (e.g., Bifidobacterium) and reduce the relative abundance of inflammation-related microbiota (e.g., Escherichia/Shigella and Ruminococcus). Interestingly, we found that the changes in the gut barrier and immunity were already present immediately after early intervention with BD-1 + Ceftri, implying that early effects can persist with appropriate intervention. Furthermore, intervention with BD-1 alone in early life confers an anti-inflammatory effect to a certain degree in the long-term, which may be due to the interaction between BD-1 and the host’s native gut microbiota affecting intestinal metabolites. In conclusion, BD-1 was not as effective as BD-1 + Ceftri in early life, perhaps due to its failure to fully play the role of the strain itself under the influence of the host’s complex microbiota. Therefore, further research is needed to explore specific mechanisms for single strain and native microbiota or the combination between probiotics and antibiotics.

Where Do We Stand in the Behavioral Pathogenesis of Inflammatory Bowel Disease? The Western Dietary Pattern and Microbiota-A Narrative Review

Despite the increasing knowledge with regard to IBD (inflammatory bowel disease), including ulcerative colitis (UC) and Crohn’s disease (CD), the etiology of these conditions is still not fully understood. Apart from immunological, environmental and nutritional factors, which have already been well documented, it is worthwhile to look at the possible impact of genetic factors, as well as the composition of the microbiota in patients suffering from IBD. New technologies in biochemistry allow to obtain information that can add to the current state of knowledge in IBD etiology.

Involvement of Proinflammatory Arachidonic Acid (ARA) Derivatives in Crohn’s Disease (CD) and Ulcerative Colitis (UC)

Recently, an increase in the incidence of inflammatory bowel disease (IBD) has been observed, especially among children and adolescents. Currently, few studies focus on the differentiation of inflammation in IBD subunits, i.e., Crohn’s Disease (CD) and Ulcerative Colitis (UC). The aim of this study was to compare the concentrations of proinflammatory mediators of arachidonic acid (ARA) and linoleic acid (LA) in patients with CD (n = 34) and UC (n = 30), in order to identify differences in inflammation in both diseases and within the same entity, according to disease activity. Sixty-four adolescents with a mean age of 13.76 ± 2.69 and 14.15 ± 3.31, for CD and UC, respectively, were enrolled in the study. Biochemical analysis of ARA and LA derivatives was performed using a liquid chromatography. A trend was observed in the concentration of 15S-HETE (hydroxyeicosatetraenoic acids) in CD relative to UC. The active phase of both diseases showed a higher 15S-HETE concentration in active CD relative to active UC. Comparing patients with CD with active and inactive disease showed a trend of increased levels of thromboxane B2, leukotriene B4 and 9S-HODE (hydroxyoctadecadienoic acid) in the active versus the inactive disease. We also observed statistically significantly higher levels of 12S-HETE in inactive CD relative to active CD. In the UC group, on the other hand, statistically significantly higher levels of prostaglandin E2 and 16RS-HETE were observed in active UC relative to inactive UC. Moreover, significantly higher concentrations of LTX A4 5S, 6R were observed in inactive UC relative to the active phase. In conclusion, the present study indicated the activity of the 15-LOX pathway in CD. Further studies involving lipid mediators in patients with IBD may contribute to the development of new therapies for the treatment of IBD. The identification of differences in the course of inflammation may help to target therapy in CD and UC, and perhaps allow the introduction of an additional diagnostic marker between the two main IBD subtypes.

The Complex Relationship Between Microbiota, Immune Response and Creeping Fat in Crohn's Disease

In the last decade, there has been growing interest in the pathological involvement of hypertrophic mesenteric fat attached to the serosa of the inflamed intestinal segments involved in Crohn's disease [CD], known as creeping fat. In spite of its protective nature, creeping fat harbours an aberrant inflammatory activity which, in an already inflamed intestine, may explain why creeping fat is associated with a greater severity of CD. The transmural inflammation of CD facilitates the interaction of mesenteric fat with translocated intestinal microorganisms, contributing to activation of the immune response. This may be not the only way in which microorganisms alter the homeostasis of this fatty tissue: intestinal dysbiosis may also impair xenobiotic metabolism. All these CD-related alterations have a functional impact on nuclear receptors such as the farnesoid X receptor or the peroxisome proliferator-activated receptor γ, which are implicated in regulation of the immune response, adipogenesis and the maintenance of barrier function, as well as on creeping fat production of inflammatory-associated cells such as adipokines. The dysfunction of creeping fat worsens the inflammatory course of CD and may favour intestinal fibrosis and fistulizing complications. However, our current knowledge of the pathophysiology and pathogenic role of creeping fat is controversial and a better understanding might provide new therapeutic targets for CD. Here we aim to review and update the key cellular and molecular alterations involved in this inflammatory process that link the pathological components of CD with the development of creeping fat.

The role of diosgenin in crohn’s disease

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammation that can grossly affect the entire gastrointestinal tract (GIT) from the mouth to the anus. Crohn’s disease is the most known type of IBD and has been the focus of attention due to its increase in prevalence worldwide. Although the etiology is yet to be elucidated, recent studies have pointed out Crohn’s disease to arise from a complex interaction between environmental influences, genetic predisposition, and altered gut microbiota, resulting in dysregulated adaptive and innate responses. The presenting hallmarks of Crohn’s disease may include weight loss, nausea, vomiting, abdominal pain, diarrhea, fever, or chills. Treatment is usually done with many approved immunosuppressive drugs and surgery. However, a promising avenue from natural compounds is a safer therapy due to its safe natural active ingredients and the strong activity it shows in the treatment and management of diseases. Diosgenin, “a major biologically active natural steroidal sapogenin found in Chinese yam,” has been widely reported as a therapeutic agent in the treatment of various classes of disorders such as hyperlipidemia, inflammation, diabetes, cancer, infection, and immunoregulation. In this review, an analysis of literature data on diosgenin employed as a therapeutic agent for the treatment of Crohn’s disease is approached, to strengthen the scientific database and curtail the dreadful impact of Crohn’s disease.

Short-Chain Naphthoquinone Protects Against Both Acute and Spontaneous Chronic Murine Colitis by Alleviating Inflammatory Responses

Ulcerative colitis (UC) is characterised by chronic, relapsing, idiopathic, and multifactorial colon inflammation. Recent evidence suggests that mitochondrial dysfunction plays a critical role in the onset and recurrence of this disease. Previous reports highlighted the potential of short-chain quinones (SCQs) for the treatment of mitochondrial dysfunction due to their reversible redox characteristics. We hypothesised that a recently described potent mitoprotective SCQ (UTA77) could ameliorate UC symptoms and pathology. In a dextran sodium sulphate- (DSS-) induced acute colitis model in C57BL/6J mice, UTA77 substantially improved DSS-induced body weight loss, disease activity index (DAI), colon length, and histopathology. UTA77 administration also significantly increased the expression of tight junction (TJ) proteins occludin and zona-occludin 1 (ZO-1), which preserved intestinal barrier integrity. Similar responses were observed in the spontaneous Winnie model of chronic colitis, where UTA77 significantly improved DAI, colon length, and histopathology. Furthermore, UTA77 potently suppressed elevated levels of proinflammatory cytokines and chemokines in colonic explants of both DSS-treated and Winnie mice. These results strongly suggest that UTA77 or its derivatives could be a promising novel therapeutic approach for the treatment of human UC.

Magnetic Living Hydrogels for Intestinal Localization, Retention, and Diagnosis

Natural microbial sensing circuits can be rewired into new gene networks to build living sensors that detect and respond to disease-associated biomolecules. However, synthetic living sensors, once ingested, are cleared from the gastrointestinal (GI) tract within 48 hours; retaining devices in the intestinal lumen is prone to intestinal blockage or device migration. To localize synthetic microbes and safely extend their residence in the GI tract for health monitoring and sustained drug release, an ingestible magnetic hydrogel carrier is developed to transport diagnostic microbes to specific intestinal sites. The magnetic living hydrogel is localized and retained by attaching a magnet to the abdominal skin, resisting the peristaltic waves in the intestine. The device retention is validated in a human intestinal phantom and an in vivo rodent model, showing that the ingestible hydrogel maintains the integrated living bacteria for up to seven days, which allows the detection of heme for GI bleeding in the harsh environment of the gut. The retention of microelectronics is also demonstrated by incorporating a temperature sensor into the magnetic hydrogel carrier.

The Function of the Histamine H4 Receptor in Inflammatory and Inflammation-Associated Diseases of the Gut

Histamine is a pleiotropic mediator involved in a broad spectrum of (patho)-physiological processes, one of which is the regulation of inflammation. Compounds acting on three out of the four known histamine receptors are approved for clinical use. These approved compounds comprise histamine H1-receptor (H₁R) antagonists, which are used to control allergic inflammation, antagonists at H₂R, which therapeutically decrease gastric acid release, and an antagonist at H₃R, which is indicated to treat narcolepsy. Ligands at H₄R are still being tested pre-clinically and in clinical trials of inflammatory diseases, including rheumatoid arthritis, asthma, dermatitis, and psoriasis. These trials, however, documented only moderate beneficial effects of H₄R ligands so far. Nevertheless, pre-clinically, H₄R still is subject of ongoing research, analyzing various inflammatory, allergic, and autoimmune diseases. During inflammatory reactions in gut tissues, histamine concentrations rise in affected areas, indicating its possible biological effect. Indeed, in histamine-deficient mice experimentally induced inflammation of the gut is reduced in comparison to that in histamine-competent mice. However, antagonists at H₁R, H₂R, and H₃R do not provide an effect on inflammation, supporting the idea that H₄R is responsible for the histamine effects. In the present review, we discuss the involvement of histamine and H₄R in inflammatory and inflammation-associated diseases of the gut.

Colonisation with endogenous Lactobacillus reuteri R28 and exogenous Lactobacillus plantarum AR17-1 and the effects on intestinal inflammation in mice

The beneficial effects of probiotics on inflammatory bowel disease (IBD) are well known, although an understanding of colonisation by endogenous and exogenous bacterial strains and the effects on intestinal inflammation remains elusive. In this study, the colonisation of endogenous Lactobacillus reuteri R28 and exogenous Lactobacillus plantarum AR17-1 was investigated in healthy or PEG-treated mice using a 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (cFDA-SE) labelling technique. The effects of these strains on mice with colitis induced by DSS and treated with PEG + DSS were also studied. Endogenous L. reuteri R28 and exogenous L. plantarum AR17-1 exhibited no significant differences in colonisation in healthy mice, whereas after PEG treatment, colonisation of the intestinal mucosa by L. reuteri R28 was greatly enhanced. L. reuteri R28 more effectively reduced diarrhoea caused by PEG, and L. plantarum AR17-1 more effectively reduced the colitis induced by PEG + DSS and downregulated the expression of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-6. These results suggest that endogenous L. reuteri R28 may easily adapt to the intestinal environment, leading to better colonisation, whereas L. plantarum AR17-1 has a stronger inhibitory effect on inflammation. This finding is relevant to the selection of probiotics.

Enhanced IL-36R signaling promotes barrier impairment and inflammation in skin and intestine

Deficiency in interleukin-36R (IL-36R) antagonist caused by loss-of-function mutations in IL-36RN leads to DITRA (deficiency of IL-36 receptor antagonist), a rare inflammatory human disease that belongs to a subgroup of generalized pustular psoriasis (GPP). We report a functional genetic mouse model of DITRA with enhanced IL-36R signaling analogous to that observed in patients with DITRA, which provides new insight into our understanding of the IL-36 family of molecules in regulating barrier integrity across multiple tissues. Humanized DITRA-like mice displayed increased skin inflammation in a preclinical model of psoriasis, and in vivo blockade of IL-36R pathway using anti-human IL-36R antibody ameliorated imiquimod-induced skin pathology as both prophylactic and therapeutic treatments. Deeper characterization of the humanized DITRA-like mice revealed that deregulated IL-36R signaling promoted tissue pathology during intestinal injury and led to impairment in mucosal restoration in the repair phase of chronic dextran sulfate sodium (DSS)-induced colitis. Blockade of IL-36R pathway significantly ameliorated DSS-induced intestinal inflammation and rescued the inability of DITRA-like mice to recover from mucosal damage in vivo. Our results indicate a central role for IL-36 in regulating proinflammatory responses in the skin and epithelial barrier function in the intestine, suggesting a new therapeutic potential for targeting the IL-36R axis in psoriasis and at the later stages of intestinal pathology in inflammatory bowel disease.

Interleukin-22 and intestinal homeostasis: Protective or destructive?

Interleukin (IL)-22 is a member of IL-10 family cytokines with various immunologic functions. As its name implies, IL-22 is known to be secreted mainly by Th22 cells, a recently discovered lineage of CD4+ T cells. Also, Th17, Th1, natural killer cells, γδT cells, and innate immune cells along with some nonlymphoid cells have been confirmed as secondary cellular sources of IL-22. Different cell types such as bronchial and intestinal epithelial cells, keratinocytes, hepatocytes, dermal fibroblasts, and tubular epithelial cells are affected by IL-22. Both pathologic and protective roles have been attributed to IL-22 in maintaining gut homeostasis and inflammation. According to the latest fast-growing investigations, IL-22 is significantly involved in various pathologies including allergic diseases, infection, autoimmunity, and cancer development. Regulating gut immune responses, barrier integrity, and inflammation is dependent on a diverse complex of cytokines and mediators which are secreted by mucosal immune cells. Several investigations have been designed to recognize the role of IL-22 in gastrointestinal immunity. This article tries to discuss the latest knowledge on this issue and clarify the potential of IL-22 to be used in the future therapeutic approaches of intestinal disorders including inflammatory bowel diseases and colon cancer.

Crohn's Disease Differentially Affects Region-Specific Composition and Aerotolerance Profiles of Mucosally Adherent Bacteria

BACKGROUND

The intestinal microbiota play a key role in the onset, progression, and recurrence of Crohn disease (CD). Most microbiome studies assay fecal material, which does not provide region-specific information on mucosally adherent bacteria that directly interact with host systems. Changes in luminal oxygen have been proposed as a contributor to CD dybiosis.

METHODS

The authors generated 16S rRNA data using colonic and ileal mucosal bacteria from patients with CD and without inflammatory bowel disease. We developed profiles reflecting bacterial abundance within defined aerotolerance categories. Bacterial diversity, composition, and aerotolerance profiles were compared across intestinal regions and disease phenotypes.

RESULTS

Bacterial diversity decreased in CD in both the ileum and the colon. Aerotolerance profiles significantly differed between intestinal segments in patients without inflammatory bowel disease, although both were dominated by obligate anaerobes, as expected. In CD, high relative levels of obligate anaerobes were maintained in the colon and increased in the ileum. Relative abundances of similar and distinct taxa were altered in colon and ileum. Notably, several obligate anaerobes, such as Bacteroides fragilis, dramatically increased in CD in one or both intestinal segments, although specific increasing taxa varied across patients. Increased abundance of taxa from the Proteobacteria phylum was found only in the ileum. Bacterial diversity was significantly reduced in resected tissues of patients who developed postoperative disease recurrence across 2 independent cohorts, with common lower abundance of bacteria from the Bacteroides, Streptococcus, and Blautia genera.

CONCLUSIONS

Mucosally adherent bacteria in the colon and ileum show distinct alterations in CD that provide additional insights not revealed in fecal material.

The relationship between the commensal microbiota levels and Crohn's disease activity

Background and aim

Human gut microbiota play an important role in metabolism and host physiology. Perturbations of the gut microbial communities lead to the development of various diseases such as inflammatory bowel disease, celiac disease, allergic diseases, and metabolic diseases. Crohn's disease is a chronic inflammatory bowel disease characterized by periods of remission and relapse. Several studies suggest that intestinal inflammation arises due to an abnormal response of the intestinal immune system to the fecal microbiota. The goal of the study was to evaluate the relative amount of four bacterial groups in fecal samples of Crohn's disease patients and their relation to the inflammatory activity.

Methods

We studied stool samples of 105 individuals, 54 with Crohn's disease and 51 as a control group. The DNA extracted from the stool samples was subjected to real‐time polymerase chain reaction (qPCR) for quantification of the Bacteroidetes phylum, class Bacilli, and Bifidobacteriaceae and Enterobacteriaceae families.

Results

We found a significant increase in Bacteroidetes in Crohn's disease samples when compared to the control group (14 650 and 2060 CFU/ng DNA, respectively) (P = 0.014). On the other hand, we observed a significant reduction in Bacilli and Bifidobacteriaceae (13 and 58 CFU/ng DNA, respectively) (P < 0.0001). In contrast, patients without any drug treatment presented an increase of Bacilli and Bifidobacteriaceae (102 521 and 6235 CFU/ng DNA, respectively) (P < 0.0001).

Conclusion

The commensal bacteria were decreased in fecal samples of participants with Crohn's disease when compared to the control group. There was no relation between the disease location and/or disease activity with the microbiota.

Probiotic mixture VSL#3: An overview of basic and clinical studies in chronic diseases

Probiotics are known as “live microorganisms” and have been proven to have a health effect on hosts at the proper dose. Recently, a kind of probiotic mixture including eight live bacterial strains, VSL#3, has attracted considerable attention for its combined effect. VSL#3 is the only probiotic considered as a kind of medical food; it mainly participates in the regulation of the intestinal barrier function, including improving tight junction protein function, balancing intestinal microbial composition, regulating immune-related cytokine expression and so on. The objective of this review is to discuss the treatment action and mechanism for the administration of VSL#3 in chronic diseases of animals and humans (including children). We found that VSL#3 has a therapeutic or preventive effect in various systemic diseases per a large number of studies, including digestive systemic diseases (gastrointestinal diseases and hepatic diseases), obesity and diabetes, allergic diseases, nervous systemic diseases, atherosclerosis, bone diseases, and female reproductive systemic diseases.

The role of the gut microbiota in the treatment of inflammatory bowel diseases

The human intestinal microbiota coevolves with its host through a symbiotic relationship and exerts great influence on substantial functions including aspects of physiology, metabolism, nutrition and regulation of immune responses leading to physiological homeostasis. Over the last years, several studies have been conducted toward the assessment of the host-gut microbiota interaction, aiming to elucidate the mechanisms underlying the pathogenesis of several diseases. A defect on the microbiota-host crosstalk and the concomitant dysregulation of immune responses combined with genetic and environmental factors have been implicated in the pathogenesis of inflammatory bowel diseases (IBD). To this end, novel therapeutic options based on the gut microbiota modulation have been an area of extensive research interest. In this review we present the recent findings on the association of dysbiosis with IBD pathogenesis, we focus on the role of gut microbiota on the treatment of IBD and discuss the novel and currently available therapeutic strategies in manipulating the composition and function of gut microbiota in IBD patients. Applicable and emerging microbiota treatment modalities, such as the use of antibiotics, prebiotics, probiotics, postbiotics, synbiotics and fecal microbiota transplantation (FMT) constitute promising therapeutic options. However, the therapeutic potential of the aforementioned approaches is a topic of investigation and further studies are needed to elucidate their position in the present treatment algorithms of IBD.

Bovine κ-Casein Fragment Induces Hypo-Responsive M2-Like Macrophage Phenotype

Immunomodulatory nutraceuticals have garnered special attention due to their therapeutic potential for the amelioration of many chronic inflammatory conditions. Macrophages are key players in the induction, propagation and resolution of inflammation, actively contributing to the pathogenesis and resolution of inflammatory disorders. As such, this study aimed to investigate the possible therapeutic effects bovine casein derived nutraceuticals exert on macrophage immunological function. Initial studies demonstrated that sodium caseinate induced a M2-like macrophage phenotype that was attributed to the kappa-casein subunit. Kappa-casein primed macrophages acquired a M2-like phenotype that expressed CD206, CD54, OX40L, CD40 on the cell surface and gene expression of Arg-1, RELM-α and YM1, archetypical M2 markers. Macrophages stimulated with kappa-casein secreted significantly reduced TNF-α and IL-10 in response to TLR stimulation through a mechanism that targeted the nuclear factor-κB signal transduction pathway. Macrophage proteolytic processing of kappa-casein was required to elicit these suppressive effects, indicating that a fragment other than C-terminal fragment, glycomacropeptide, induced these modulatory effects. Kappa-casein treated macrophages also impaired T-cell responses. Given the powerful immuno-modulatory effects exhibited by kappa-casein and our understanding of immunopathology associated with inflammatory diseases, this fragment has the potential as an oral nutraceutical and therefore warrants further investigation.

Apolipoprotein A-I mimetics mitigate intestinal inflammation in COX2-dependent inflammatory bowel disease model

Cyclooxygenase 2 (Cox2) total knockout and myeloid knockout (MKO) mice develop Crohn's-like intestinal inflammation when fed cholate-containing high fat diet (CCHF). We demonstrated that CCHF impaired intestinal barrier function and increased translocation of endotoxin, initiating TLR/MyD88-dependent inflammation in Cox2 KO but not WT mice. Cox2 MKO increased pro-inflammatory mediators in LPS-activated macrophages, and in the intestinal tissue and plasma upon CCHF challenge. Cox2 MKO also reduced inflammation resolving lipoxin A4 (LXA4) in intestinal tissue, while administration of an LXA4 analog rescued disease in Cox2 MKO mice fed CCHF. The apolipoprotein A-I (APOA1) mimetic 4F mitigated disease in both the Cox2 MKO/CCHF and piroxicam-accelerated Il10-/- models of inflammatory bowel disease (IBD) and reduced elevated levels of pro-inflammatory mediators in tissue and plasma. APOA1 mimetic Tg6F therapy was also effective in reducing intestinal inflammation in the Cox2 MKO/CCHF model. We further demonstrated that APOA1 mimetic peptides: i) inhibited LPS and oxidized 1-palmitoyl-2-arachidonoyl-sn-phosphatidylcholine (oxPAPC) dependent pro-inflammatory responses in human macrophages and intestinal epithelium; and ii) directly cleared pro-inflammatory lipids from mouse intestinal tissue and plasma. Our results support a causal role for pro-inflammatory and inflammation resolving lipids in IBD pathology and a translational potential for APOA1 mimetic peptides for the treatment of IBD.

An H2S-activated ratiometric CO photoreleaser enabled by excimer/monomer conversion

Based on the excimer-monomer conversion of a pyrene-flavone hybrid, a ratiometric CO photoreleaser, PFN, was constructed for simultaneous H2S quantification and CO release in inflammatory cells.

Application of Proteomics to Inflammatory Bowel Disease Research: Current Status and Future Perspectives

Inflammatory bowel disease (IBD) is a chronic relapsing/remitting inflammatory illness of the gastrointestinal tract of unknown aetiology. Despite recent advances in decoding the pathophysiology of IBD, many questions regarding disease pathogenesis remain. Genome-wide association studies (GWAS) and knockout mouse models have significantly advanced our understanding of genetic susceptibility loci and inflammatory pathways involved in IBD pathogenesis. Despite their important contribution to a better delineation of the disease process in IBD, these genetic findings have had little clinical impact to date. This is because the presence of a given gene mutation does not automatically correspond to changes in its expression or final metabolic or structural effect(s). Furthermore, the existence of these gene susceptibility loci in the normal population suggests other driving prerequisites for the disease manifestation. Proteins can be considered the main functional units as almost all intracellular physiological functions as well as intercellular interactions are dependent on them. Proteomics provides methods for the large-scale study of the proteins encoded by the genome of an organism or a cell, to directly investigate the proteins and pathways involved. Understanding the proteome composition and alterations yields insights into IBD pathogenesis as well as identifying potential biomarkers of disease activity, mucosal healing, and cancer progression. This review describes the state of the art in the field with respect to the study of IBD and the potential for translation from biomarker discovery to clinical application.

IL-33 Protects Mice against DSS-Induced Chronic Colitis by Increasing Both Regulatory B Cell and Regulatory T Cell Responses as Well as Decreasing Th17 Cell Response

BACKGROUND

Previously, we have reported that IL-33 functioned as a protective modulator in dextran sulfate sodium- (DSS-) induced chronic colitis by suppressing Th17 cell response in colon lamina propria and IL-33 induced both regulatory B cells (Bregs) and regulatory T cells (Tregs) in mesenteric lymph nodes (MLNs) of mice with DSS-induced acute colitis. Moreover, we speculated that IL-33 would promote the Treg or Breg responses leading to the attenuation of DSS-induced chronic colitis. So, we investigated the role of IL-33 on Bregs and Tregs in the MLN of DSS-induced chronic colitis mice.

METHODS

IL-33 was administered by intraperitoneal injection to mice with DSS-induced chronic colitis. Clinical symptoms, colon length, and histological changes were determined. The production of cytokines was measured by ELISA. The T and B cell subsets were measured by flow cytometry. The expression of mRNA of transcription factors was measured by quantitative real-time PCR.

RESULTS

We show that IL-33 treatment increases both Breg and Treg responses in the MLN of mice with DSS-induced chronic colitis. Moreover, IL-33 treatment also decreases Th17 cell response in the MLN of mice with DSS-induced chronic colitis.

CONCLUSION

Our data provide clear evidence that IL-33 plays a protective role in DSS-induced chronic colitis, which is closely related to increasing Breg and Treg responses in the MLN of mice as well as suppressing Th17 cell responses.

Clinical Efficacy of Serum-Derived Bovine Immunoglobulin in Patients With Refractory Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel disease (IBD) can have autoimmunity and/or intestinal barrier dysfunction as part of pathophysiology and may be refractory to all available treatment options. Serum-derived bovine immunoglobulin (SBI) binds microbial components with postulated downstream effects of normalized gut immune and barrier function, which may be useful for managing IBD. The purpose of our study was to evaluate the effectiveness of SBI in the management of refractory IBD, particularly symptoms of chronic diarrhea and loose stools.

METHODS

We retrospectively analyzed charts for patients diagnosed with IBD (n = 40) who were refractory to standard treatment. Patients received oral SBI 5 g daily for a period of at least 6 weeks. Twelve patients with IBD fulfilled study inclusion criteria. Each patient graded the severity and frequency of gastrointestinal symptoms before starting SBI and at 6 weeks of treatment using a standardized patient assessment form. Means and standard deviations for all symptom scores at baseline and week 6 of treatment were analyzed.

RESULTS

Mean symptom scores decreased significantly for nausea (P = 0.02 for severity and P = 0.03 for mean symptom score) and diarrhea (P = 0.0006, P = 0.0001 and P = 0.0001 for severity, frequency and mean symptom score, respectively).

CONCLUSIONS

Therapy with SBI alleviated some refractory gastrointestinal symptoms in patients with IBD, including nausea and diarrhea. Increased duration, dosage and/or frequency of SBI might provide additional symptom improvement and could be tested through controlled clinical trials with larger sample sizes and longer follow-up.

NOD2 up-regulates TLR2-mediated IL-23p19 expression via NF-κB subunit c-Rel in Paneth cell-like cells

IL-23p19 plays important roles in intestinal antimicrobial immunity, while its over-expression can lead to intestinal inflammation. However, the bacterial compounds and the type of pattern recognition receptor involved in the inducible expression of IL-23p19 in Paneth cells remain unclear. Here we show that the mRNA expression of IL-23p19 was increased in Paneth cell (PC)-like cells stimulated by Toll-like receptor 2 (TLR2) ligands, peptidoglycan (PGN) and Pam3CSK4, and was further increased in the presence of nucleotide-binding oligomerization domain 2 (NOD2)-ligand muramyl dipeptide (MDP). However, its mRNA expression was decreased in NOD2-knockdown PC-like cells. Additionally, the c-Rel activation was increased in Pam3CSK4- or PGN-stimulated PC-like cells, but the PGN-induced c-Rel activation was decreased in NOD2-knockdown PC-like cells and had no significant difference compared with Pam3CSK4-induced c-Rel activation. Our results suggest that NOD2 up-regulates TLR2-mediated IL-23p19 expression via increasing c-Rel activation in PC-like cells. This finding might provide us with a novel therapeutic target for inflammatory bowel disease to inhibit IL-23p19 over-expression via the NOD2-c-Rel pathway.

l-Glutamine Attenuates DSS-Induced Colitis via Induction of MAPK Phosphatase-1

Inflammatory bowel disease (IBD), encompassing ulcerative colitis and Crohn’s disease, is a multifactorial inflammatory disease of the small intestine and colon. Many investigators have reported that l-glutamine (Gln) therapy improves outcomes of experimental colitis models, although the mechanism is not fully understood. Regarding the anti-inflammatory properties of Gln, we have shown that Gln can effectively deactivate cytosolic phospholipase A₂ (cPLA₂) by rapid induction of MAPK phosphatase (MKP)-1. In this study, we explore the possibility that Gln ameliorates dextran sulfate sodium (DSS)-induced colitis via MKP-1 induction, resulting in inhibition of cPLA₂, which has been reported to play a key role in the pathogenesis of IBD. Oral Gln intake attenuated DSS-induced colitis. Gln inhibited cPLA₂ phosphorylation, as well as colonic levels of TNF-α and leukotriene (LT)B₄. Gln administration resulted in early and enhanced MKP-1 induction. Importantly, MKP-1 small interfering RNA (siRNA), but not control siRNA, significantly abrogated the Gln-mediated (1) induction of MKP-1; (2) attenuation of colitis (colon length, histological abnormality, and inflammation; and (3) inhibition of cPLA₂ phosphorylation and colonic levels of TNF-α and LTB₄. These data indicated that Gln ameliorated DSS-induced colitis via MKP-1 induction.

Updated review on immune factors in pathogenesis of Crohn's disease

Although the incidence of Crohn's disease (CD) in China is not as high as that in European and American countries, there has been a clear increasing trend in recent years. Little is known about its pathogenesis, cause of deferment, and the range of complications associated with the disease. Local and international scholars have presented many hypotheses about CD pathogenesis based on experimental and clinical studies, including genetic susceptibility, immune function defects, intestinal microflora disorders, delayed hypersensitivity, and food antigen stimulation. However, the specific mechanism leading to this immune imbalance, which causes persistent intestinal mucosal damage, and the source of the inflammatory cascade reaction are still unclear. So far, the results of research studies differ locally and internationally. This paper presents the most current research on immune factors in the pathogenesis of CD.

Serum Interleukin 9 Levels Predict Disease Severity and the Clinical Efficacy of Infliximab in Patients with Crohn's Disease

BACKGROUND

Interleukin (IL)-9 drives gut inflammation, but its role in Crohn's disease (CD) is unclear. We aimed to analyze correlations between serum IL-9 levels and disease severity and to evaluate their predictive value in relation to the clinical efficacy of infliximab (IFX) in patients with CD.

METHODS

Between January 2013 and December 2015, 100 consecutive patients with active CD and 50 age- and sex-matched control individuals were recruited from a tertiary center. Their serum IL-9 levels were measured using an enzyme-linked immunosorbent assay. Correlations between the serum IL-9 levels and disease severity were examined. The serum IL-9 level was explored as a predictor of clinical remission and mucosal healing at week 30 in 50 patients for whom IFX therapy was administered.

RESULTS

The serum IL-9 levels were significantly higher in the patients with active CD (22.0 pg/mL) than in the control individuals (6.3 pg/mL) (P < 0.001); they differed according to disease severity (moderate-to-severe CD: 29.1 pg/mL versus mild CD: 12.9 pg/mL) (P < 0.001), and they correlated well with the clinical activity of CD. IFX lowered the serum IL-9 level in patients who achieved efficacy at week 30. The areas under the curves for the IL-9 levels at weeks 14 and 30 that could predict clinical remission and mucosal healing at week 30 were 0.803 and 0.752 and 0.746 and 0.781, respectively.

CONCLUSIONS

Serum IL-9 levels correlate with disease severity and the clinical efficacy of IFX in patients with CD, and IL-9 may be a promising novel biomarker for CD monitoring.

Clinical remission in patients with moderate-to-severe Crohn's disease treated with filgotinib (the FITZROY study): results from a phase 2, double-blind, randomised, placebo-controlled trial

BACKGROUND

Filgotinib (GLPG0634, GS-6034) is a once-daily, orally administered, Janus kinase 1 (JAK1)-selective inhibitor. The FITZROY study examined the efficacy and safety of filgotinib for the treatment of moderate-to-severe Crohn's disease.

METHODS

We did a randomised, double-blind, placebo-controlled phase 2 study, which recruited patients from 52 centres in nine European countries. We enrolled eligible patients aged 18-75 years with a documented history of ileal, colonic, or ileocolonic Crohn's disease for 3 months or more before screening, as assessed by colonoscopy and supported by histology, and a Crohn's Disease Activity Index (CDAI) score during screening between 220 and 450 inclusive. Patients were randomly assigned (3:1) to receive filgotinib 200 mg once a day or placebo for 10 weeks. Patients were stratified according to previous anti-tumour necrosis factor alpha exposure, C-reactive protein concentration at screening (≤10 mg/L or >10 mg/L), and oral corticosteroid use at baseline, using an interactive web-based response system. The primary endpoint was clinical remission, defined as CDAI less than 150 at week 10. After week 10, patients were assigned based on responder status to filgotinib 100 mg once a day, filgotinib 200 mg once a day, or placebo for an observational period lasting a further 10 weeks. The filgotinib and placebo treatment groups were compared using ANCOVA models and logistic regression models containing baseline values and randomisation stratification factors as fixed effects. Analyses were done on the intention-to-treat non-responder imputation set. The trial was registered at ClinicalTrials.gov, number NCT02048618.

FINDINGS

Between Feb 3, 2014, and July 10, 2015, we enrolled 174 patients with active Crohn's disease confirmed by centrally read endoscopy (130 in the filgotinib 200 mg group and 44 in the placebo group). In the intention-to-treat population, 60 (47%) of 128 patients treated with filgotinib 200 mg achieved clinical remission at week 10 versus ten (23%) of 44 patients treated with placebo (difference 24 percentage points [95% CI 9-39], p=0·0077). In a pooled analysis of all periods of filgotinib and placebo exposure over 20 weeks, serious treatment-emergent adverse effects were reported in 14 (9%) of 152 patients treated with filgotinib and three (4%) of 67 patients treated with placebo.

INTERPRETATION

Filgotinib induced clinical remission in significantly more patients with active Crohn's disease compared with placebo, and had an acceptable safety profile.

FUNDING

Galapagos.

Association between Polymorphisms in Antioxidant Genes and Inflammatory Bowel Disease

Inflammation is the driving force in inflammatory bowel disease (IBD) and its link to oxidative stress and carcinogenesis has long been accepted. The antioxidant system of the intestinal mucosa in IBD is compromised resulting in increased oxidative injury. This defective antioxidant system may be the result of genetic variants in antioxidant genes, which can represent susceptibility factors for IBD, namely Crohn's disease (CD) and ulcerative colitis (UC). Single nucleotide polymorphisms (SNPs) in the antioxidant genes SOD2 (rs4880) and GPX1 (rs1050450) were genotyped in a Portuguese population comprising 436 Crohn's disease and 367 ulcerative colitis patients, and 434 healthy controls. We found that the AA genotype in GPX1 is associated with ulcerative colitis (OR = 1.93, adjusted P-value = 0.037). Moreover, we found nominal significant associations between SOD2 and Crohn's disease susceptibility and disease subphenotypes but these did not withstand the correction for multiple testing. These findings indicate a possible link between disease phenotypes and antioxidant genes. These results suggest a potential role for antioxidant genes in IBD pathogenesis and should be considered in future association studies.

Inflammatory Bowel Disease: Pathophysiology and Current Therapeutic Approaches

Inflammatory bowel diseases, most commonly categorized as Crohn's disease and ulcerative colitis, are immune mediated chronic inflammatory disorders of the gastrointestinal tract. The etiopathogenesis is multifactorial with different environmental, genetic, immune mediated, and gut microbial factors playing important role. The current goals of therapy are to improve clinical symptoms, control inflammation, prevent complications, and improve quality of life. Different therapeutic agents, with their indications, mechanisms of action, and side effects are discussed in this chapter. Anti-integrin therapy, a newer therapeutic class, with its potential beneficial role in both Crohn's disease and ulcerative colitis is also mentioned. In the end, therapeutic algorithms for both diseases are reviewed.

Evaluation of therapeutic effect of low dose naltrexone in experimentally-induced Crohn's disease in rats

BACKGROUND AND AIM

Crohn's disease is a relapsing inflammatory condition afflicting the digestive tract. Drugs used for treatment of Crohn's disease may be associated with serious side effects. Endogenous opioid peptides modulate inflammatory cytokine production. Opioid antagonists have been shown to play a role in healing and repair of tissues. This work was designed to detect the possible beneficial effects of opioid antagonist naltrexone in indomethacin-induced Crohn's disease in rats.

EXPERIMENTAL APPROACH

Enteritis was induced in male albino rats by two subcutaneous injection of indomethacin in a dose of 7.5mg/kg 24h apart started on day one. Salfasalazine, naltrexone and their combination were administered orally from day one of induction of enteritis to day 10. Disease activity index, serum levels of C-reactive protein and tumor necrosis factor-α, macroscopic and microscopic pathological scores and in vitro motility studies were evaluated.

RESULTS

Induction of enteritis resulted in significant increase of disease activity index, significant elevation of serum levels of C-reactive protein and tumor necrosis factor-α, significant deterioration of pathological scores and significant increase in the mean contractility response of the isolated ileal segments compared with normal untreated rats. Treatment with sulfasalazine, low dose of natrexone or their combination resulted in significant improvement of all measured parameters compared with enteritis group.

CONCLUSION

The current finding could provide new interesting opportunity for developing new therapeutic approaches for treatment of Crohn's disease. Use of naltrexone, especially in small dose, has little side effects making it of interest for treatment of Crohn's disease. Also, it provides the possibility of reduced doses of other drugs if it is used as combined therapy.

Circadian rhythm abnormalities - Association with the course of inflammatory bowel disease

Crohn's disease (CD) and ulcerative colitis (UC) are the main representatives of inflammatory bowel diseases (IBD), a group of chronic, immune system-mediated inflammatory diseases of the gastrointestinal (GI) tract. The pathogenesis of the intestinal lesions in IBD is not entirely identified and understood: excessive activation of the immune system may come as a result of the interaction of various environmental and infectious factors, genetic predisposition, and the mediation of abnormal intestinal flora. The main objective of the current study is to further identify the risk factors for the development of IBD. Currently, there is very little knowledge about circadian rhythm and IBD and there are only a few studies on the relationship between sleep disturbances and the course of the disease, as well as pro- and anti-inflammatory cytokine profile and general immune system functioning. Furthermore, the relationship between the expression of circadian rhythm genes and severe course of IBD is still unknown. The aim of this review is to show the current state of knowledge about the relationship between circadian rhythm disorders, sleep disturbance and inflammation in the GI tract and to analyze the possibility of employing this knowledge in diagnosis and treatment of IBD.