Drug advances in inflammatory bowel disease

Fat and proteolysis due to methionine, tryptophan, and niacin deficiency leads to alterations in gut microbiota and immune modulation in inflammatory bowel disease

Inflammatory bowel disease (IBD) is one of the intractable diseases. Nutritional components associated with IBD have been identified, and it is known that excessive methionine intake exacerbates inflammation, and that tryptophan metabolism is involved in inflammation. Analysis of the gut microbiota has also progressed, where Lactobacillus regulate immune cells in the intestine and suppress inflammation. However, whether the methionine and tryptophan metabolic pathways affect the growth of intestinal Lactobacillus is unknown. Here we show how transient methionine, tryptophan, and niacin deficiency affects the host and gut microbiota in mouse models of colitis (induced by dextran sodium sulfate) fed a methionine-deficient diet (1K), tryptophan and niacin-deficient diet (2K), or methionine, tryptophan, and niacin-deficient diet (3K). These diets induced body weight decrease and 16S rRNA analysis of mouse feces revealed the alterations in the gut microbiota, leading to a dramatic increase in the proportion of Lactobacillus in mice. Intestinal RNA sequencing data confirmed that the expression of several serine proteases and fat-metabolizing enzymes were elevated in mice fed with methionine, tryptophan, and niacin (MTN) deficient diet. In addition, one-carbon metabolism and peroxisome proliferator-activated receptor (PPAR) pathway activation were also induced with MTN deficiency. Furthermore, changes in the expression of various immune-related cytokines were observed. These results indicate that methionine, tryptophan, and niacin metabolisms are important for the composition of intestinal bacteria and host immunity. Taken together, MTN deficiencies may serve as a Great Reset of gut microbiota and host gene expression to return to good health.

Perceptions, behaviours and barriers towards exercise practices in inflammatory bowel disease

Inflammatory bowel disease (IBD), a chronic disease affecting the digestive tract, has a significant impact on health-related quality of life. Pharmaceutical treatment is typically adopted, yet exercise is increasingly becoming recognized as an adjunct therapy. This study aimed to explore the perspectives, behaviours, and barriers of IBD patients in terms of their exercise habits. A 16-item closed-ended questionnaire was completed by 463 adult IBD patients (Ulcerative colitis = 57.02%, Crohn's dis-ease = 40.60% and Other = 2.38%) (Female = 76.67%, Male = 22.46 and Non-binary = 0.86%). The questionnaire was divided into three sections: baseline/demographic characteristics, disease characteristics, and exercise perceptions, beliefs, and behaviours. Significantly (P<0.001) more participants (63.07%) reported that they engage regularly with exercise compared to those who do not; however, engagement was significantly lower in female patients (59.72%) compared to males (74.04%). Respondents also rated significantly (P<0.001) that a combination of factors prevents engagement in exercise (74.30%). Moderate intensity exercise was the predominant (P<0.001) aerobic modality (39.04%), the majority (P<0.001) response was that patients undertake no resistance training (27.74%), and significantly more (P<0.001) patients indicated that they don't know whether resistance training can influence IBD either positively (57.53%) or negatively (62.33%). Whilst it is encouraging that IBD patients are engaging regularly with exercise, the reduced levels of engagement in females and lack of knowledge/ engagement with resistance training, indicate that future implementation and educational developments are necessary to enhance exercise in females and resistance training engagement in all IBD patients.

Chlorogenic Acid Attenuates Dextran Sodium Sulfate-Induced Ulcerative Colitis in Mice through MAPK/ERK/JNK Pathway

Objective

Observe the protective effect of chlorogenic acid on dextran sulfate-induced ulcerative colitis in mice and explore the regulation of MAPK/ERK/JNK signaling pathway.

Methods

Seventy C57BL/6 mice (half males and half females) were randomly divided into 7 groups, 10 in each group: control group (CON group), UC model group (UC group), and sulfasalazine-positive control group (SASP group), chlorogenic acid low dose group (CGA-L group), chlorogenic acid medium dose group (CGA-M group), chlorogenic acid high dose group (CGA-H group), and ERK inhibitor + chlorogenic acid group (E+CGA group). The effects of chlorogenic acid on UC were evaluated by colon mucosa damage index (CMDI), HE staining, immunohistochemistry, ELISA, and Western blot. The relationship between chlorogenic acid and MAPK/ERK/JNK signaling pathway was explored by adding ERK inhibitor.

Results

The UC models were established successfully by drinking DSS water. Chlorogenic acid reduces DSS-induced colonic mucosal damage, inhibits DSS-induced inflammation, oxidative stress, and apoptosis in colon, and reduces ERK1/2, p -ERK, p38, p-p38, JNK, and p-JNK protein expression. ERK inhibitor U0126 reversed the protective effect of chlorogenic acid on colon tissue.

Conclusion

Chlorogenic acid can alleviate DSS-induced ulcerative colitis in mice, which can significantly reduce tissue inflammation and apoptosis, and its mechanism is related to the MAPK/ERK/JNK signaling pathway.

Luteolin suppresses the JAK/STAT pathway in a cellular model of intestinal inflammation

Current treatment strategies for inflammatory bowel diseases (IBDs) are associated with a lower efficacy and with several side effects that strongly affect the quality of life of IBD patients. Consequently, the development of new therapies, combining efficacy and safety is an important goal in the field of intestinal inflammation. In this context, evidence supports that polyphenols can be promising candidates due to their ability to modulate intracellular inflammatory signalling cascades. Luteolin, a naturally occurring flavonoid, exhibits anti-inflammatory properties in several models of inflammation. However, its action against intestinal inflammation has been poorly explored. Therefore, there is a lack of scientific knowledge about the potential impact of luteolin in the intestinal inflammation, particularly regarding the underlying molecular mechanisms by which luteolin can exert its anti-inflammatory action. We assessed the potential anti-inflammatory effect of luteolin in a cellular model of intestinal inflammation using cytokine-stimulated HT-29 colon epithelial cells, and the underlying key molecular mechanisms were identified. Luteolin significantly inhibited interleukine-8 (IL-8) production, cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression and nitric oxide (˙NO) overproduction induced by cytokines, indicating that luteolin negatively modulates key inflammatory signalling cascades underlying intestinal inflammation. Mechanistically, the inhibition of the JAK/STAT pathway was identified as a critical mechanism by which luteolin exerts its intestinal anti-inflammatory action. This study uncovers novel molecular mechanisms by which luteolin may act against intestinal inflammation, which might support the use of luteolin as a future therapeutic strategy in IBD.

Anatomical Road Mapping Using CT and MR Enterography for Ultrasound Molecular Imaging of Small Bowel Inflammation in Swine

OBJECTIVES

To evaluate the feasibility and time saving of fusing CT and MR enterography with ultrasound for ultrasound molecular imaging (USMI) of inflammation in an acute small bowel inflammation of swine.

METHODS

Nine swine with ileitis were scanned with either CT (n = 3) or MR (n = 6) enterography. Imaging times to load CT/MR images onto a clinical ultrasound machine, fuse them to ultrasound with an anatomical landmark-based approach, and identify ileitis were compared to the imaging times without anatomical road mapping. Inflammation was then assessed by USMI using dual selectin-targeted (MB_Selectin) and control (MB_Control) contrast agents in diseased and healthy control bowel segments, followed by ex vivo histology.

RESULTS

Cross-sectional image fusion with ultrasound was feasible with an alignment error of 13.9 ± 9.7 mm. Anatomical road mapping significantly reduced (P < 0.001) scanning times by 40%. Localising ileitis was achieved within 1.0 min. Subsequently performed USMI demonstrated significantly (P < 0.001) higher imaging signal using MB_Selectin compared to MB_Control and histology confirmed a significantly higher inflammation score (P = 0.006) and P- and E-selectin expression (P ≤ 0.02) in inflamed vs. healthy bowel.

CONCLUSIONS

Fusion of CT and MR enterography data sets with ultrasound in real time is feasible and allows rapid anatomical localisation of ileitis for subsequent quantification of inflammation using USMI.

KEY POINTS

• Real-time fusion of CT/MRI with ultrasound to localise ileitis is feasible. • Anatomical road mapping using CT/MRI significantly decreases the scanning time for USMI. • USMI allows quantification of inflammation in swine, verified with ex vivo histology.

Mucosal healing did not predict sustained clinical remission in patients with IBD after discontinuation of one-year infliximab therapy

Aim

To assess the endoscopic activity and Clinical activity after a one-year period of infliximab therapy and to evaluate the association between mucosal healing and need for retreatment after stopping infliximab in patients with Inflammatory bowel disease (IBD).

Methods

The data from 109 patients with Crohn’s disease (CD) and 107 patients with Ulcerative colitis (UC) received one-year infliximab were assessed. The primary endpoint of the study was the proportion of clinical remission, mucosal healing and full remission in IBD after the one-year period of maintenance infliximab therapy. The secondary endpoint was the frequency of relapses in the next year.

Results

A total of 84.4% (92/109) CD patients and 81.3% (87/107) UC patients achieved clinical remission, 71.56% (78/109) of CD patients and 69.16% (74/107) of UC patients achieved mucosal healing, 56.88% (62/109) of CD patients and 54.21% (58/107) of UC patients achieved full remission at the end of the year of infliximab therapy. Infliximab therapy was restarted in the 10.19% (22/216) patients (13 CD, 9 UC) who achieved mucosal healing, and 13.89% (30/216) patients (18 CD, 12 UC) who achieved clinical remission and 6.48% (14/216) patients (8 CD, 6 UC) who achieved full remission had to be retreated within the next year. Neither clinical remission nor mucosal healing was associated with the time to restarting Infliximab therapy in IBD.

Conclusion

Mucosal healing did not predict sustained clinical remission in patients with IBD in whom the infliximab therapies had been stopped. And stopping or continuing infliximab therapy may be determined by assessing the IBD patient’s general condition and the clinical activity.

Worm proteins of Schistosoma mansoni reduce the severity of experimental chronic colitis in mice by suppressing colonic proinflammatory immune responses

Although helminthic therapy as a possible new option to treat inflammatory bowel disease is a well-established concept by now, the search for immunomodulatory helminth-derived compounds and their mechanisms of action is still ongoing. We investigated the therapeutic potential and the underlying immunological mechanisms of Schistosoma mansoni soluble worm proteins (SmSWP) in an adoptive T cell transfer mouse model of chronic colitis. Both a curative and a preventive treatment protocol were included in this study. The curative administration of SmSWP (started when colitis was established), resulted in a significant improvement of the clinical disease score, colonoscopy, macroscopic and microscopic inflammation score, colon length and myeloperoxidase activity. The therapeutic potential of the preventive SmSWP treatment (started before colitis was established), was less pronounced compared with the curative SmSWP treatment but still resulted in an improved clinical disease score, body weight loss, colon length and microscopic inflammation score. Both the curative and preventive SmSWP treatment downregulated the mRNA expression of the proinflammatory cytokines IFN-γ and IL-17A and upregulated the mRNA expression of the anti-inflammatory cytokine IL-4 in the colon at the end of the experiment. This colonic immunomodulatory effect of SmSWP could not be confirmed at the protein level. Moreover, the effect of SmSWP appeared to be a local colonic phenomenon, since the flow cytometric T cell characterization of the mesenteric lymph nodes and the cytokine measurements in the serum did not reveal any effect of SmSWP treatment. In conclusion, SmSWP treatment reduced the severity of colitis in the adoptive transfer mouse model via the suppression of proinflammatory cytokines and the induction of an anti-inflammatory response in the colon.

Mangiferin attenuates the symptoms of dextran sulfate sodium-induced colitis in mice via NF-κB and MAPK signaling inactivation

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gastrointestinal (GI) tract, and currently no curative treatment is available. Mangiferin, a natural glucosylxanthone mainly from the fruit, leaves and stem bark of a mango tree, has a strong anti-inflammatory activity. We sought to investigate whether mangiferin attenuates inflammation in a mouse model of chemically induced IBD. Pre-administration of mangiferin significantly attenuated dextran sulfate sodium (DSS)-induced body weight loss, diarrhea, colon shortening and histological injury, which correlated with the decline in the activity of myeloperoxidase (MPO) and the level of tumor necrosis factor-α (TNF-α) in the colon. DSS-induced degradation of inhibitory κBα (IκBα) and the phosphorylation of nuclear factor-kappa B (NF-κB) p65 as well as the mRNA expression of pro-inflammatory mediators (inducible NO synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), TNF-α, interleukin-1β (IL-1β) and IL-6) in the colon were also downregulated by mangiferin treatment. Additionally, the phosphorylation/activation of DSS-induced mitogen-activated protein kinase (MAPK) proteins was also inhibited by mangiferin treatment. In accordance with the in vivo results, mangiferin exposure blocked TNF-α-stimulated nuclear translocation of NF-κB in RAW264.7 mouse macrophage cells. Transient transfection gene reporter assay performed in TNF-α-stimulated HT-29 human colorectal adenocarcinoma cells indicated that mangiferin inhibits NF-κB transcriptional activity in a dose-dependent manner. The current study clearly demonstrates a protective role for mangiferin in experimental IBD through NF-κB and MAPK signaling inhibition. Since mangiferin is a natural compound with little toxicity, the results may contribute to the effective utilization of mangiferin in the treatment of human IBD.

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.