Immunologic and molecular mechanisms in inflammatory bowel disease

Linderanine C regulates macrophage polarization by inhibiting the MAPK signaling pathway against ulcerative colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory disease involving the mucosa and submucosa of the rectum and colon. Lindera aggregate (Sims) Kosterm is a traditional Chinese herb used for thousands of years in the treatment of gastrointestinal diseases. Previously, we have demonstrated that the extracts of Lindera aggregate have good anti-UC effects, but their pharmacodynamic active components have not been fully clarified. Therefore, we explored the therapeutic effect of Linderanine C (LDC), a characteristic component of Lindera aggregata, on UC and its mechanism in this study. Firstly, we found that LDC could significantly reduce the disease activity index of UC and improve shortened colon and pathological changes in vivo. Colon tissue transcriptomics suggested that the anti-UC effect of LDC might be related to its anti-inflammatory activity. Cellular experiments revealed that LDC could inhibit the expression of the M1 cell marker CD86 in RAW264.7 cells, reduce the production of inflammatory mediators such as IL-6 and TNF-α, and have good anti-inflammatory activity in vitro. Cellular transcriptomics reveal the potential involvement of the MAPK signaling pathway in the anti-inflammatory effect of LDC. The co-culture assay confirmed that LDC could significantly reduce inflammation-mediated intestinal epithelial cell injury. In conclusion, LDC was able to inhibit macrophage M1 polarization and reduce inflammatory mediator production by inhibiting the MAPK signaling pathway, effectively improving UC.

The Effect of Protein Nutritional Support on Inflammatory Bowel Disease and Its Potential Mechanisms

Inflammatory bowel disease (IBD), a complex chronic inflammatory bowel disorder that includes Crohn's disease (CD) and Ulcerative Colitis (UC), has become a globally increasing health concern. Nutrition, as an important factor influencing the occurrence and development of IBD, has attracted more and more attention. As the most important nutrient, protein can not only provide energy and nutrition required by patients, but also help repair damaged intestinal tissue, enhance immunity, and thus alleviate inflammation. Numerous studies have shown that protein nutritional support plays a significant role in the treatment and remission of IBD. This article presents a comprehensive review of the pathogenesis of IBD and analyzes and summarizes the potential mechanisms of protein nutritional support in IBD. Additionally, it provides an overview of the clinical effects of protein nutritional support in IBD and its impact on clinical complications. Research findings reveal that protein nutritional support demonstrates significant benefits in improving clinical symptoms, reducing the risk of complications, and improving quality of life in IBD patients. Therefore, protein nutritional support is expected to provide a new approach for the treatment of IBD.

Mechanistic insight: Linking cardiovascular complications of inflammatory bowel disease

Cardiovascular diseases (CVD) are the leading cause of mortality worldwide despite an aggressive reduction of traditional cardiovascular risk factors. Underlying inflammatory conditions such as inflammatory bowel disease (IBD) increase the risk of developing CVD. A broad understanding of the underlying pathophysiological processes between IBD and CVD is required to treat and prevent cardiovascular events in patients with IBD. This review highlights the commonality between IBD and CVD, including dysregulated immune response, genetics, environmental risk factors, altered gut microbiome, stress, endothelial dysfunction and abnormalities, to shed light on an essential area of modern medicine.

Biodegradable Polymeric Nanoparticles Loaded with Flavonoids: A Promising Therapy for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of disorders that cause chronic non-specific inflammation in the gastrointestinal (GI) tract, primarily affecting the ileum and colon. The incidence of IBD has risen sharply in recent years. Despite continuous research efforts over the past decades, the aetiology of IBD is still not fully understood and only a limited number of drugs are available for its treatment. Flavonoids, a ubiquitous class of natural chemicals found in plants, have been widely used in the prevention and treatment of IBD. However, their therapeutic efficacy is unsatisfactory due to poor solubility, instability, rapid metabolism, and rapid systemic elimination. With the development of nanomedicine, nanocarriers can efficiently encapsulate various flavonoids and subsequently form nanoparticles (NPs), which greatly improves the stability and bioavailability of flavonoids. Recently, progress has also been made in the methodology of biodegradable polymers that can be used to fabricate NPs. As a result, NPs can significantly enhance the preventive or therapeutic effects of flavonoids on IBD. In this review, we aim to evaluate the therapeutic effect of flavonoid NPs on IBD. Furthermore, we discuss possible challenges and future perspectives.

Dietary Intake and Systemic Inflammation: Can We Use Food as Medicine?

PURPOSE OF REVIEW

This review summarizes the current literature regarding the association between diet and systemic inflammation.

RECENT FINDINGS

Data in humans suggests that consumption of plant-based nutrients is associated with a reduction in systemic inflammation, while consumption of red meat and excessive dairy has the opposite effect and may increase risk of acute flares in those that suffer from certain chronic diseases like inflammatory bowel disease or psoriasis and certain cancers. There is a known association between diet and systemic inflammation; thus, we recommend that clinicians discuss plant-based, whole food diets with patients, particularly those that suffer from chronic inflammatory diseases as an adjunct treatment for these conditions. Future research should evaluate whether adherence to these types of diets is sustainable in the long term and how these changes affect important quality of life concerns.

Modern drug discovery for inflammatory bowel disease: The role of computational methods

Inflammatory bowel diseases (IBDs) comprising ulcerative colitis, Crohn’s disease and microscopic colitis are characterized by chronic inflammation of the gastrointestinal tract. IBD has spread around the world and is becoming more prevalent at an alarming rate in developing countries whose societies have become more westernized. Cell therapy, intestinal microecology, apheresis therapy, exosome therapy and small molecules are emerging therapeutic options for IBD. Currently, it is thought that low-molecular-mass substances with good oral bio-availability and the ability to permeate the cell membrane to regulate the action of elements of the inflammatory signaling pathway are effective therapeutic options for the treatment of IBD. Several small molecule inhibitors are being developed as a promising alternative for IBD therapy. The use of highly efficient and time-saving techniques, such as computational methods, is still a viable option for the development of these small molecule drugs. The computer-aided (in silico) discovery approach is one drug development technique that has mostly proven efficacy. Computational approaches when combined with traditional drug development methodology dramatically boost the likelihood of drug discovery in a sustainable and cost-effective manner. This review focuses on the modern drug discovery approaches for the design of novel IBD drugs with an emphasis on the role of computational methods. Some computational approaches to IBD genomic studies, target identification, and virtual screening for the discovery of new drugs and in the repurposing of existing drugs are discussed.

The Intestinal Barrier-Shielding the Body from Nano- and Microparticles in Our Diet

Nano- and microparticles are an implicit part of the human diet. They are unknowingly ingested with our food that contains them as additives or pollutants. However, their impact on human health is not yet understood and controversially discussed. The intestinal epithelial barrier shields our body against exogenous influences, such as commensal bacteria, pathogens, and body-foreign particles and, therefore, protects our body integrity. Breakdown of the intestinal epithelial barrier and aberrant immune responses are key events in the pathogenesis of inflammatory bowel disease (IBD). Epithelial lesions might enable systemic translocation of nano- and microparticles into the system, eventually triggering an excessive immune response. Thus, IBD patients could be particularly vulnerable to adverse health effects caused by the ingestion of synthetic particles with food. The food-additive titanium dioxide (TiO2) serves as a coloring agent in food products and is omnipresent in the Western diet. TiO2 nanoparticles exacerbate intestinal inflammation by activation of innate and adaptive immune response. Because of serious safety concerns, the use of TiO2 as a food additive was recently banned from food production within the European Union. Due to environmental pollution, plastic has entered the human food chain, and plastic microparticles have been evidenced in the drinking water and comestible goods. The impact of plastic ingestion and its resulting consequences on human health is currently the subject of intense research. Focusing on TiO2 and plastic particles in the human diet and their impact on epithelial integrity, gut homeostasis, and intestinal inflammation, this review is addressing contemporary hot topics which are currently attracting a lot of public attention.

Impact of intrarectal chromofungin treatment on dendritic cells-related markers in different immune compartments in colonic inflammatory conditions

BACKGROUND

Chromofungin (CHR: chromogranin-A 47-66) is a chromogranin-A derived peptide with anti-inflammatory and anti-microbial properties. Ulcerative colitis (UC) is characterized by a colonic decrease of CHR and a dysregulation of dendritic CD11c⁺ cells.

AIM

To investigate the association between CHR treatment and dendritic cells (DCs)-related markers in different immune compartments in colitis.

METHODS

A model of acute UC-like colitis using dextran sulphate sodium (DSS) was used in addition to biopsies collected from UC patients.

RESULTS

Intrarectal CHR treatment reduced the severity of DSS-induced colitis and was associated with a significant decrease in the expression of CD11c, CD40, CD80, CD86 and interleukin (IL)-12p40 in the inflamed colonic mucosa and CD11c, CD80, CD86 IL-6 and IL-12p40 within the mesenteric lymph nodes and the spleen. Furthermore, CHR treatment decreased CD80 and CD86 expression markers of splenic CD11c⁺ cells and decreased NF-κB expression in the colon and of splenic CD11c⁺ cells. In vitro, CHR decreased CD40, CD80, CD86 IL-6 and IL-12p40 expression in naïve bone marrow-derived CD11c⁺ DCs stimulated with lipopolysaccharide. Pharmacological studies demonstrated an impact of CHR on the NF-κB pathway. In patients with active UC, CHR level was reduced and showed a negative linear relationship with CD11c and CD86.

CONCLUSION

CHR has protective properties against intestinal inflammation via the regulation of DC-related markers and CD11c⁺ cells. CHR could be a potential therapy of UC.

Potential Roles of Exosomal lncRNAs in the Intestinal Mucosal Immune Barrier

The intestinal mucosal immune barrier protects the host from the invasion of foreign pathogenic microorganisms. Immune cells and cytokines in the intestinal mucosa maintain local and systemic homeostasis by participating in natural and adaptive immunity. Deficiency of the intestinal mucosal immune barrier is associated with a variety of intestinal illnesses. Exosomes are phospholipid bilayer nanovesicles that allow cell-cell communication by secreting physiologically active substances including proteins, lipids, transcription factors, mRNAs, micro-RNAs (miRNAs), and long noncoding RNAs (lncRNAs). Exosomal lncRNAs are involved in immune cell differentiation and the modulation of the immune response. This review briefly introduces the potential role of exosomal lncRNAs in the intestinal mucosal immune barrier and discusses their relevance to intestinal illnesses.

Effect of T. spiralis Serine protease inhibitors on TNBS-induced experimental colitis mediated by Macrophages

Inflammatory bowel disease (IBD) is an autoimmune disease with increasing incidence rate, and divided into ulcerative colitis (UC) and Crohn’s disease (CD). And more and more experimental evidence supports that immune disorder is important in the pathogenesis of IBD. Our previous experiments have confirmed that TsKaSPI and TsAdSPI recombinant proteins could relieve TNBS (2,4,6-Trinitrobenzenesulfonic acid solution)-induced colitis. Therefore, we speculate that macrophages play a certain role in the process of recombinant protein relieving colitis. In this experiment, 96 male BALB/c mice aged 6–8 weeks were randomly divided into two groups: the prevention group and the therapy group. Changes of the ratio of M1/M2 phenotypic macrophages in spleens and MLNs, key factors in the IL-33/ST2 and IL-6/JAK2/STAT3 signaling pathway were detected. The purpose is to analyze the specific role played by macrophages and their secreted cytokines in the immunomodulation of colitis by Trichinella spiralis (T. spiralis) Serine protease inhibitors. The results showed that the percentage of M1 phenotypic macrophages was decreased and M2 phenotypic macrophages was increased in the TsKaSPI + TNBS, TsAdSPI + TNBS group compared with the PBS + TNBS group in the prevention group. Meanwhile, the expression of IL-33 and ST2 were significantly decreased. The key factors of IL-6/JAK2/STAT3 signaling pathway were all significantly increased. In addition, in the therapy group, we found similar results. This experiment demonstrated that macrophages have a certain impact during this process of recombinant protein relieving mouse CD model.

A Comprehensive Review and Update on the Pathogenesis of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and life-threating inflammatory disease of gastroenteric tissue characterized by episodes of intestinal inflammation. The pathogenesis of IBD is complex. Recent studies have greatly improved our knowledge of the pathophysiology of IBD, leading to great advances in the treatment as well as diagnosis of IBD. In this review, we have systemically reviewed the pathogenesis of IBD and highlighted recent advances in host genetic factors, gut microbiota, and environmental factors and, especially, in abnormal innate and adaptive immune responses and their interactions, which may hold the keys to identify novel predictive or prognostic biomarkers and develop new therapies.

Caenorhabditis elegans as a Model Host to Monitor the Candida Infection Processes

C. elegans has several advantages as an experimental host for the study of infectious diseases. Worms are easily maintained and propagated on bacterial lawns. The worms can be frozen for long term storage and still maintain viability years later. Their short generation time and large brood size of thousands of worms grown on a single petri dish, makes it relatively easy to maintain at a low cost. The typical wild type adult worm grows to approximately 1.5 mm in length and are transparent, allowing for the identification of several internal organs using an affordable dissecting microscope. A large collection of loss of function mutant strains are readily available from the C. elegans genetic stock center, making targeted genetic studies in the nematode possible. Here we describe ways in which this facile model host has been used to study Candida albicans, an opportunistic fungal pathogen that poses a serious public health threat.

Herb-partitioned moxibustion alleviates colon injuries in ulcerative colitis rats

AIM

To observe the effect of herb-partitioned moxibustion (HPM) on expression of colonic cytokines in ulcerative colitis (UC) rats.

METHODS

A UC rat model was established by protein immunization in combination with topical chemical stimulation. Rats in the HPM group (n = 8) received HPM at bilateral Tianshu (ST25) points. The gross injury and pathological scores of the colon were recorded. The expression profile of colonic cytokines was assayed using the protein microarray technique. Specific differential cytokines were selected and verified by ELISA. The corresponding UniProt Accessions of the differentially expressed cytokines were retrieved in the UniProt database. The pathways involved were analyzed with the help of the KEGG PATHWAY database. The DAVID database was used for functional cluster and pathway analysis.

RESULTS

HPM improved colon injuries in UC rats, manifested by accelerated repair of ulcers and alleviation of inflammation, and the gross injury and pathological scores both significantly decreased (P < 0.01). Fold change > 1.3 or < 0.77 was taken as the screening standard. There were 77 down-regulated and 9 up-regulated differentially expressed colonic cytokines in the HPM group compared with the model group, and expression of 20 differed significantly (P < 0.05). Twelve of the 20 significantly differentially expressed cytokines [β-catenin, interleukin-1 receptor 6 (IL-1R6), IL-1β, B7-1, nerve growth factor receptor, AMP-activated protein kinase-α1, neuropilin-2, orexin A, adipocyte differentiation-related protein, IL-2, Fas and FasL] were up-regulated in the model group (n = 3, compared with the normal group) but down-regulated in the HPM group (n = 3, compared with the model group). Functional cluster analysis showed that the differentially expressed colonic cytokines in the HPM group regulated apoptosis and protein phosphorylation. KEGG pathway analysis showed that 52 down-regulated and 7 up-regulated differentially expressed colonic cytokines in the HPM group had pathways. The pathways that interacted between the cytokines and their receptors accounted for the largest proportion (28 of the down-regulated and 5 of the up-regulated cytokines).

CONCLUSION

HPM promotes the repair of colon injuries in UC rats, which is related to the regulation of several abnormally expressed cytokines.

Portulaca Extract Attenuates Development of Dextran Sulfate Sodium Induced Colitis in Mice through Activation of PPARγ

Portulaca oleracea L. is a traditional Chinese medicine, which has been used as adjuvant therapy for inflammatory bowel disease (IBD). However, the mechanism of its activity in IBD still remains unclear. Since previous studies have documented the anti-inflammatory effect of peroxisome proliferator activated receptors-γ (PPAR-γ), Portulaca regulation of PPAR-γ in inflammation was examined in current study. Ulcerative colitis (UC) was generated by 5% dextran sulfate sodium (DSS) in mice and four groups were established as normal control, DSS alone, DSS plus mesalamine, and DSS plus Portulaca. Severity of UC was evaluated by body weight, stool blood form, and length of colorectum. Inflammation was examined by determination of inflammatory cytokines (TNF-a, IL-6, and IL-1a). Portulaca extract was able to attenuate development of UC in DSS model similar to the treatment of mesalazine. Moreover, Portulaca extract inhibited proinflammatory cytokines release and reduced the level of DSS-induced NF-κB phosphorylation. Furthermore, Portulaca extract restored PPAR-γ level, which was reduced by DSS. In addition, Portulaca extract protected DSS induced apoptosis in mice. In conclusion, Portulaca extract can alleviate colitis in mice through regulation of inflammatory reaction, apoptosis, and PPAR-γ level; therefore, Portulaca extract can be a potential candidate for the treatment of IBD.

Larval Echinococcus multilocularis infection reduces dextran sulphate sodium-induced colitis in mice by attenuating T helper type 1/type 17-mediated immune reactions

The tumour‐like growth of larval Echinococcus multilocularis tissue (causing alveolar echinococcosis, AE) is directly linked to the nature/orientation of the periparasitic host immune‐mediated processes. Parasite‐mediated immune suppression is a hallmark triggering infection outcome in both chronic human and murine AE. So far, little is known about secondary systemic immune effects of this pathogen on other concomitant diseases, e.g. endogenous gut inflammation. We examined the influence of E. multilocularis infection on murine dextran sodium sulphate (DSS) ‐induced colitis. At 3 months after E. multilocularis infection (chronic stage), the mice were challenged with 3% DSS in the drinking water for 5 days plus subsequently with tap water (alone) for another 4 days. After necropsy, fixed tissues/organs were sectioned and stained with haematoxylin & eosin for assessing inflammatory reactions. Cytokine levels were measured by flow cytometry and quantitative RT‐PCR. Colitis severity was assessed (by board‐certified veterinary pathologists) regarding (i) colon length, (ii) weight loss and (iii) a semi‐quantitative score of morphological changes. The histopathological analysis of the colon showed a significant reduction of DSS‐induced gut inflammation by concomitant E. multilocularis infection, which correlated with down‐regulation of T helper type 1 (Th1)/Th17 T‐cell responses in the colon tissue. Echinococcus multilocularis infection markedly reduced the severity of DSS‐induced gut inflammation upon down‐regulation of Th1/Th17 cytokine expression and attenuation of CD11b⁺ cell activation. In conclusion, E. multilocularis infection remarkably reduces DSS‐induced colitis in mice by attenuating Th1/Th17‐mediated immune reactions.

Anti-inflammatory effects and corresponding mechanisms of cirsimaritin extracted from Cirsium japonicum var. maackii Maxim

In this study, we investigated the anti-inflammatory effects and mechanisms of cirsimaritin isolated from an ethanol extract of the aerial parts of Cirsium japonicum var. maackii Maxim. using RAW264.7 cells. The extract and its flavonoid cirsimaritin inhibited nitric oxide (NO) production and inducible nitric oxide synthase expression in RAW264.7 cells. Cirsimaritin inhibited interleukin-6, tumor necrosis factor-α, and NO production in a concentration-dependent manner in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. From a western blot study, pretreatment with cirsimaritin inhibited phosphorylation/degradation of IκBα and phosphorylation of Akt in LPS-stimulated RAW264.7 cells. Moreover, cirsimaritin suppressed activation of LPS-induced transcription factors, such as c-fos and signal transducer and activator of transcription 3 (STAT3), in RAW264.7 cells. Collectively, these results show that cirsimaritin possesses anti-inflammatory activity, which is regulated by inhibition of c-fos and STAT3 phosphorylation in RAW264.7 cells.

Effect of TGF-β1 neutralizing antibody on intestinal fibrosis in a mouse model of chronic colitis induced with trinitrobenzene sulfonic acid

AIM

To evaluate the effect of transforming growth factor-β₁ (TGF-β₁) neutralizing antibody on intestinal fibrosis in a mouse model of chronic colitisinduced with trinitrobenzene sulfonic acid (TNBS).

METHODS

Forty-eight Balb/c mice were randomly divided into a normal control group, a model control group, a treatment control group, and a TGF-β₁ antibody group. Chronic colitis and intestinal fibrosis were induced with TNBS/ethanol enema for 6 wk. Mice in the TGF-β₁ antibody group and treatment control group were administered with TGF-β₁ neutralizing antibody and physiological saline, respectively, at 24 h after the administration of TNBS/ethanol enema. The pathological changes in intestine tissue were detected by HE and VG collage staining. Expression of TGF-β₁ and collagen types Ⅰ, Ⅲ, and Ⅴ mRNAs in the colon was detected.

RESULTS

HE and VG collage staining showed that pathologic histology was improved in the TGF-β₁ antibody group. The expression of collagen types Ⅰ, Ⅲ, and Ⅴ and TGF-β₁ mRNAs decreased significantly in the TGF-β₁ antibody group compared with the model control group and the treatment control group (P < 0.05). The protein expression of TGF-β₁ also decreased significantly in the TGF-β₁ antibody group compared with the model control group and the treatment control group (P < 0.05).

CONCLUSION

TGF-β₁ neutralizing antibody can effectively down-regulate the expression of TGF-β₁ and collagen in mice with chronic colitis, and intestinal fibrosis can be abrogated by targeting TGF-β₁.

Recent Advances: The Imbalance of Cytokines in the Pathogenesis of Inflammatory Bowel Disease

Cytokines play an important role in the immunopathogenesis of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, where they drive and regulate multiple aspects of intestinal inflammation. The imbalance between proinflammatory and anti-inflammatory cytokines that occurs in IBD results in disease progression and tissue damage and limits the resolution of inflammation. Targeting cytokines have been novel strategies in the treatment of IBD. Recent studies show the beneficial effects of anticytokine treatments to IBD patients, and multiple novel cytokines are found to be involved in the pathogenesis of IBD. In this review, we will discuss the recent advances of novel biologics in clinics and clinical trials, and novel proinflammatory and anti-inflammatory cytokines found in IBD with focusing on IL-12 family and IL-1 family members as well as their relevance to the potential therapy of IBD.

Progress in medical treatment of ulcerative colitis

Ulcerative colitis (UC) is a kind of chronic inflammatory disease and its etiology and pathogenesis are not clear. Accumulating evidence has indicated that the interactions among genotype, immune system and intestinal microbiota of patients play a significant role in the pathogenesis of UC. At present, it is difficult to cure UC. The main goals of UC treatment include inducing remission rapidly, maintaining the remission stage for a long time and preventing the occurrence of complications. As the incidence of UC keeps rising sharply in the recent 20 years, and a portion of patients have no response to the treatments or the effects are not satisfying, it is necessary to make further research for the treatment of UC. There are some main medical treatments for UC, such as 5-ASA, immune inhibitors, biological agents, Chinese herbal medicine, antibiotics and probiotics. In recent years, some new treatments such as stem cell transplantation, fecal bacteria transplantation and CO enema treatment are becoming the hot spot of research. This article will make a summary of the progress in medical treatment of UC in recent years.

Loss of NHE8 expression impairs intestinal mucosal integrity

The newest member of the Na(+)/H(+) exchanger (NHE) family, NHE8, is abundantly expressed at the apical membrane of the intestinal epithelia. We previously reported that mucin 2 expression was significantly decreased in the colon in NHE8(-/-) mice, suggesting that NHE8 is involved in intestinal mucosal protection. In this study, we further evaluated the role of NHE8 in intestinal epithelial protection after dextran sodium sulfate (DSS) challenge. Compared with wild-type mice, NHE8(-/-) mice have increased bacterial adhesion and inflammation, especially in the distal colon. NHE8(-/-) mice are also susceptible to DSS treatment. Real-time PCR detected a remarkable increase in the expression of IL-1β, IL-6, TNF-α, and IL-4 in DSS-treated NHE8(-/-) mice compared with DSS-treated wild-type littermates. Immunohistochemistry showed a disorganized epithelial layer in the colon of NHE8(-/-) mice. Periodic acid-Schiff staining showed a reduction in the number of mature goblet cells and the area of the goblet cell theca in NHE8(-/-) mice. Phyloxine/tartrazine staining revealed a decrease in functional Paneth cell population in the NHE8(-/-) small intestinal crypt. The expression of enteric defensins was also decreased in NHE8(-/-) mice. The reduced mucin production in goblet cells and antimicrobial peptides production in Paneth cells lead to disruption of the intestinal mucosa protection. Therefore, NHE8 may be involved in the establishment of intestinal mucosal integrity by regulating the functions of goblet and Paneth cells.

Decrease of CD4(+) CD25(+) CD127(low) FoxP3(+) regulatory T cells with impaired suppressive function in untreated ulcerative colitis patients

Regulatory T (Treg) cells take part in immune homeostasis and play a pivotal role in maintaining peripheral tolerance. The aim of this study was to evaluate the frequency and function of Treg cells in active and untreated ulcerative colitis (UC) patients. Thirty-two subjects with newly diagnosed UC and 31 age-matched healthy controls were included in this survey. The frequency of Tregs was analyzed with flow cytometry using CD4, CD25, CD127 and FoxP3 markers. We used surface expression of CD4(+), CD25(+) and CD127(low) markers for isolation of a relatively pure Treg population. Suppressive activity of Tregs was determined by measuring their ability to inhibit the proliferation of T responder cells. UC patients had a lower frequency of CD4(+) CD25(+) CD127(low) FoxP3(+) Treg cells. Additionally, Treg cell-mediated suppression was lower in UC patients compared to controls. The frequency and suppressive capacity of Tregs and MFI of FoxP3 were inversely correlated with disease activity. These results suggest that CD4(+) CD25(+) CD127(low) FoxP3(+) Treg cells may contribute to immunopathogenesis of UC, and assessment of Treg cell frequency and function may have clinical value.

Of worms, mice and man: an overview of experimental and clinical helminth-based therapy for inflammatory bowel disease

The incidence of inflammatory and autoimmune disorders is highest in well-developed countries which is directly related to their higher hygienic standards: it is suggested that the lack of exposure to helminths contributes to the susceptibility for immune-related diseases. Epidemiological, experimental and clinical data support the idea that helminths provide protection against immune-mediated diseases such as inflammatory bowel disease (IBD). The most likely mechanism for the suppression of immune responses by helminths is the release of helminth-derived immunomodulatory molecules. This article reviews the experimental and clinical studies investigating the therapeutic potential of helminth-based therapy in IBD and also focuses on the current knowledge of its immunomodulatory mechanisms of action highlighting innate as well as adaptive immune mechanisms. Identifying the mechanisms by which these helminths and helminth-derived molecules modulate the immune system will help in creating novel drugs for the treatment of IBD and other disorders that result from an overactive immune response.

Natural products as a source of anti-inflammatory agents associated with inflammatory bowel disease

Accumulating epidemiological and clinical study indicates that inflammation is a significant risk factor to develop various human diseases such as inflammatory bowel disease (IBD), chronic asthma, rheumatoid arthritis, multiple sclerosis, and psoriasis. Suppressing inflammation is therefore important to control or prevent various diseases. Among them, IBD is one of the major problems affecting people worldwide. IBD affects at least one in a thousand persons in many Western countries. Various natural products have been shown to safely suppress pro-inflammatory pathway and control IBD. In vivo and/or in vitro studies indicate that anti-IBD effects of natural products occur by inhibition of the expression of pro-inflammatory cytokines (for example, tumor necrosis factor-α (TNF-α), intercellular adhesion molecule expression and pro-inflammatory mediators (such as inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2), master transcription factors (such as nuclear factor-κB (NF-κB)), reactive oxygen species (ROS) and by improving the antioxidant activity. In this review, we summarize recent research focused on IBD and the effects that natural products have on IBD factors.

NHE8 plays an important role in mucosal protection via its effect on bacterial adhesion

The Na⁺/H⁺ exchanger NHE8 is expressed on the apical membrane of intestinal epithelial cells and is particularly abundant in the colon. Our previous study showed that Muc2 expression was significantly reduced in NHE8-knockout (NHE8-/-) mice, suggesting that NHE8 plays a role in mucosal protection in the colon. The current study confirms and extends our studies on the role of NHE8 in mucosal protection. The number of bacteria attached on the distal colon was significantly increased in NHE8-/- mice compared with their wild-type littermates. As expected, IL-4 expression was markedly increased in NHE8-/- mice compared with wild-type mice. Immunohistochemistry showed disorganization in the mucin layer of NHE8-/- mice, suggesting a possible direct bacteria-epithelia interaction. Furthermore, NHE8-/- mice were susceptible to dextran sodium sulfate-induced mucosal injury. In wild-type mice, dextran sodium sulfate treatment inhibited colonic NHE8 expression. In Caco-2 cells, the absence of NHE8 expression resulted in higher adhesion rates of Salmonella typhimurium but not Lactobacillus plantarum. Similarly, in vivo, S. typhimurium adhesion rate was increased in NHE8-/- mice compared with wild-type mice. Our study suggests that NHE8 plays important roles in protecting intestinal epithelia from infectious bacterial adherence.

Genetic polymorphisms of interleukin 20 (IL-20) in patients with ulcerative colitis

Interleukin (IL)-20 belongs to the IL-10 family and is a potent immunomodulatory cytokine with implications for pathogenesis in the inflammatory bowel disease (IBD). The interleukin 20 gene is located within a 200kb region of q31-32 locus of chromosome 1. No previous studies have reported this novel association between ulcerative colitis (UC) and IL-20 polymorphisms. In the present work, we evaluated the role of IL-20 gene polymorphisms as susceptibility markers for UC. Three polymorphisms of IL-20 gene (rs2981573, rs2232360, rs1518108) were genotyped by 5' exonuclease TaqMan genotyping assays on an ABI Prism 7900 HT Fast Real-Time PCR system in a group of 198 Mexican Mestizo patients with UC and 698 ethnically matched healthy unrelated individuals with no family history of UC. We found significant decreased frequencies of two IL-20 genotypes: GG (rs2981573) [10.6% vs. 17.6%, p=0.017, OR=0.55, 95% CI: 0.33-0.93] and GG (rs2232360) [10.6% vs. 17.6%, p=0.017, OR=0.55, 95% CI: 0.33-0.93] in UC patients as compared to healthy controls. No significant differences of gene frequencies were found between UC patients and healthy controls in the rs1518108 polymorphism. In the subgroup analysis, no differences were found between the IL-20 genotypes and the clinical characteristics of UC. The results suggest that the GG genotypes of the IL-20 polymorphisms (rs2981573 and rs2232360) might have an important role in the development of UC in the Mexican population.

Increased expression of chemokine receptor CCR3 and its ligands in ulcerative colitis: the role of colonic epithelial cells in in vitro studies

Human colonic epithelial cells express T helper type 1 (Th1)-associated chemoattractants, yet little is known about the production of Th2-associated chemoattractants. CCL11/eotaxin-1, CCL24/eotaxin-2 and CCL26/eotaxin-3 are known to attract CCR3-expressing, Th2-polarized lymphocytes. We studied constitutive and inflammation-induced expression and production of CCR3 together with its ligands in the colon and peripheral blood of patients with inflammatory bowel disease (IBD) by flow cytometry, reverse transcription–polymerase chain reaction (RT–PCR) and enzyme-linked immunosorbent assay (ELISA). We further defined the regulated expression of these chemokines by RT–PCR and ELISA using cultured human epithelial cell lines. A higher fraction of peripheral T lymphocytes were found to be positive for CCR3 in patients with ulcerative colitis (UC) compared to Crohn’s disease (CD), while almost no CCR3(+) T cells were found in normal controls (NC). Similarly, higher and more frequent expression of CCR3 was observed in colonic biopsies from patients with UC, regardless of the disease activity, when compared to CD or NCs. Serum CCL11/eotaxin-1 was increased significantly in UC (306 ± 87 pg/ml) and less so in CD (257 ± 43 pg/ml), whereas CCL24/eotaxin-2, and CCL26/eotaxin-3 were increased only in UC. Colonic expression of the three chemokines was minimal in NCs but high in inflammatory bowel diseases (especially UC) and was independent of disease activity. Th2, and to a lesser extent Th1, cytokines were able to induce expression and production of all three eotaxins from colonic epithelial cells in culture. CCR3 and ligands over-expression would appear to be a characteristic of UC. The production of CCR3 ligands by human colonic epithelial cells suggests further that epithelium can play a role in modulating pathological T cell-mediated mucosal inflammation.

A review of the efficacy of traditional Iranian medicine for inflammatory bowel disease

The etiology of inflammatory bowel disease (IBD) is not yet known, but many factors such as defects in the immune system, oxidative stress, microbial content in the gastrointestinal tract, nuclear factor (NF)-κB, nitric oxide (NO), cyclooxygenase-2 (Cox-2), and leukotriene B4 (LB4) are thought to play a role in its pathogenesis. In traditional Iranian medicine (TIM), several medicinal plants are thought to be effective for the treatment of IBD. In this study, information on all of these remedies were derived from all available old sources such as documents or notes and books and were added to the information derived from modern medical databases covering all in vitro, in vivo and clinical trials. For some of these plants, only one or two mechanisms of action have been found such as in Cassia fistula, Lepidium sativum, and Bunium persicum. However, for some plants various mechanisms of action are known. For example, Commiphora mukul is effective in IBD due to its immunomodulatory, antioxidant, and antibacterial properties and it decreases NF-κB, NO and Cox-2. Another herb, Plantago ovata, has immunomodulatory, antioxidant, anti-inflammatory and wound healing activities and decreases NO and LB4. Considering the mechanisms of action of these plants, the combination of some of them may be useful because of their many mechanisms of action such as Pistacia lentiscus, Bunium persicum, Solanum nigrum, Plantago ovata, Boswellia, Solanum nigrum, Plantago ovata and Commiphora mukul. For some of the herbal products used in TIM such as oleogum resin from Commiphora myrrha, seeds of Ocimum basilicum, seeds of Linum usitatissimum, gum resin of Dracaena cinnabari, seeds of Plantago major, seeds of Lallementia royleana, and seeds of Allium porrum, there is no or not enough studies to confirm their benefits in IBD. It is suggested that an evaluation of the effects of these plants on different aspects of IBD should be performed.

Reciprocal changes of Foxp3 expression in blood and intestinal mucosa in IBD patients responding to infliximab

BACKGROUND

Immune therapies may act in inflammatory bowel diseases (IBD) by modulating regulatory T cells (Tregs). Therefore, we investigated the effect of infliximab (IFX) therapy on Forkhead box protein3 (Foxp3) T cells in blood and intestinal mucosa from Crohn's disease (CD) and ulcerative colitis (UC).

METHODS

Forty patients with active IBD (23 CD / 17 UC) were treated with IFX 5 mg/kg intravenously at weeks 0, 2, 6, and each 8 weeks thereafter. Blood samples were obtained before every infusion and T-lymphocyte subsets were characterized by flow cytometry. Foxp3 expression in intestinal biopsies from 43 patients with active IBD (19 CD / 24 UC) before and after IFX infusion and from 6 controls were assessed by quantitative reverse-transcription polymerase chain reaction and immunohistochemistry. Plasma C-reactive protein (CRP), clinical response, and endoscopic healing data were collected in parallel.

RESULTS

IFX therapy resulted in a significant and sustained relative increase of CD4(+)CD25(+)Foxp3(+) Treg and of CD4(+)CD25(-)Foxp3(+) Treg cells in peripheral blood (both P < 0.0001 compared to baseline), particularly in responders (both P < 0.05 compared to nonresponders). The change in CRP over time inversely correlated with the increase of CD25(+)Foxp3(+) cells (P < 0.001, r = -0.39) and durable clinical response was associated with a sustained increase of circulating Foxp3(+) cells. Surprisingly, IFX therapy downregulated mucosal mRNA and protein expression of Foxp3 in UC and CD responders (both P < 0.001) but not in nonresponders.

CONCLUSIONS

IFX therapy has opposite effects in Foxp3(+) Treg cells in blood and gut mucosa, which suggests a redistribution of this important T-cell subset.

Alterations of peripheral blood CD5+ B cells in inflammatory bowel disease

OBJECTIVE

CD5(+) B cells comprise a unique subset of B cells that modulates innate as well as autoimmune systems. The aim of this study was to investigate alterations of the circulating CD5(+) B-cell subset in patients with inflammatory bowel disease (IBD) by evaluating various clinical parameters, including therapeutic regimens.

MATERIAL AND METHODS

Thirty-four patients with ulcerative colitis (UC), 19 patients with Crohn's disease (CD), and 46 healthy control subjects were enrolled in this study. CD5(+) B cells in peripheral blood collected from each subject were analyzed by flow cytometry. Multiple regression analysis was carried out to evaluate the factors related to the circulating CD5(+) B-cell subset in the IBD patients. In an in vitro examination, dexamethasone-induced apoptosis in peripheral blood B cells was examined by detecting cell surface binding of the annexin-V antibody.

RESULTS

Age and gender in the control subjects did not influence the circulating CD5(+) B-cell subset. Multiple regression analysis showed that the presence of UC, corticosteroid therapy, and number of white blood cells in peripheral blood each had a significant influence in decreasing the number of circulating CD5(+) B cells in the IBD patients. Furthermore, in vitro results showed that dexamethasone treatment significantly induced apoptosis in CD5(+) B cells, though apoptosis was similarly observed in CD5(-) B cells.

CONCLUSIONS

CD5(+) B cells may be involved in the pathogenesis of UC, and modulation of this subset by corticosteroid therapy may play a role in the treatment of IBD patients.

Ibuprofen and hydrogel-released ibuprofen in the reduction of inflammation-induced migration in melanoma cells

BACKGROUND

There is growing evidence that inflammation may exacerbate cancer metastasis and several clinical studies show that taking nonsteroidal anti-inflammatory drugs appears to reduce metastases.

OBJECTIVES

The aims of this study were: (i) to examine the effects of ibuprofen on the major proinflammatory cytokine tumour necrosis factor (TNF)-alpha induction of migration of C8161 and HBL human melanoma cells; (ii) to develop ibuprofen-releasing hydrogels (Pluronics F127) for future topical use in reducing metastatic spread of primary melanoma; and (iii) to examine whether the actions of ibuprofen might be explained by induction of apoptosis.

METHODS

Melanoma cells were exposed to 300 U mL(-1) TNF-alpha for a 24-h period prior to making a scratch wound to which ibuprofen or ibuprofen-loaded hydrogels were then added. The effects of relevant concentrations of ibuprofen on cell viability and apoptosis were examined.

RESULTS

Ibuprofen at 10(-3) mol L(-1) significantly reduced TNF-alpha-stimulated migration of both cell types to that of nonstimulated cells (P < 0.001). TNF-alpha-unstimulated cell migration was not significantly affected. Cells responded similarly to SS and SR forms of ibuprofen. Cells treated with ibuprofen sodium salt-loaded hydrogels showed a significant reduction in migration when compared with unloaded hydrogels. Ibuprofen induced apoptosis in HBL cells but had no effect on C8161 melanoma cells apoptosis at concentrations that reduced migration.

CONCLUSIONS

These results demonstrate that TNF-alpha upregulated malignant melanoma migration in vitro and that this could be reduced by ibuprofen both in solution and delivered from a hydrogel. These effects of ibuprofen cannot be attributed simply to induction of apoptosis.

Research progress in mechanisms of intestinal fibrosis in Crohn's disease

The relationship between fibrosis and normal repair are not understood. Acute injury may cause normal mesenchymal cells to convert to fibrogenic phenotype that may lead to fibrosis when inappropriately sustained. Crohn's disease (CD)-associated fibrosis results from chronic transmural inflammation. Intestinal inflammation in CD is transmural, often associated with extracellular matrix changes, luminal narrowing and stricture formation. But the pathogenesis of stricture formation remains unclear. Current therapies do not alter its progression to intestinal fibrosis and obstruction. The aim of this review is to discuss the current understanding of fibrogenesis in CD.

Role of cytokines in inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), represents a group of chronic disorders characterized by inflammation of the gastrointestinal tract, typically with a relapsing and remitting clinical course. Mucosal macrophages play an important role in the mucosal immune system, and an increase in the number of newly recruited monocytes and activated macrophages has been noted in the inflamed gut of patients with IBD. Activated macrophages are thought to be major contributors to the production of inflammatory cytokines in the gut, and imbalance of cytokines is contributing to the pathogenesis of IBD. The intestinal inflammation in IBD is controlled by a complex interplay of innate and adaptive immune mechanisms. Cytokines play a key role in IBD that determine T cell differentiation of Th1, Th2, T regulatory and newly described Th17 cells. Cytokines levels in time and space orchestrate the development, recurrence and exacerbation of the inflammatory process in IBD. Therefore, several cytokine therapies have been developed and tested for the treatment of IBD patients.

Worms and the treatment of inflammatory bowel disease: are molecules the answer?

The lack of exposure to helminth infections, as a result of improved living standards and medical conditions, may have contributed to the increased incidence of IBD in the developed world. Epidemiological, experimental, and clinical data sustain the idea that helminths could provide protection against IBD. Studies investigating the underlying mechanisms by which helminths might induce such protection have revealed the importance of regulatory pathways, for example, regulatory T-cells. Further investigation on how helminths influence both innate and adaptive immune reactions will shed more light on the complex pathways used by helminths to regulate the hosts immune system. Although therapy with living helminths appears to be effective in several immunological diseases, the disadvantages of a treatment based on living parasites are explicit. Therefore, the identification and characterization of helminth-derived immunomodulatory molecules that contribute to the protective effect could lead to new therapeutic approaches in IBD and other immune diseases.

Interleukin-23 and its receptor in Crohn's disease

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract and clinically presents either as Crohn's disease (CD) or as ulcerative colitis (UC). The incidence of IBD has increased in recent years and there is an increased risk for developing IBD in cohorts with a higher socioeconomic class. The underlying cause for the disease remains unknown. Studies have shown that IBD is associated with environmental, genetic and immunological factors. Immunoregulation disorder lays a key role in the development of IBD. IBD is a bacteria and cytokine-driven pathologic immune response and CD is mainly involved in the immune reaction mediated by type 1 helper T-cells (Th1). IL-23 plays an important role in the immune reaction mediated by Th1 cells. In this paper, we review the molecular immunologic pathogenesis of IL-23 and IL-23R in CD for a better understanding of the etiology of and the therapy for IBD.