Immunology of inflammatory bowel disease and molecular targets for biologics

Macrophage Tim-3 maintains intestinal homeostasis in DSS-induced colitis by suppressing neutrophil necroptosis

T-cell immunoglobulin domain and mucin domain-3 (Tim-3) is a versatile immunomodulator that protects against intestinal inflammation. Necroptosis is a type of cell death that regulates intestinal homeostasis and inflammation. The mechanism(s) underlying the protective role of macrophage Tim-3 in intestinal inflammation is unclear; thus, we investigated whether specific Tim-3 knockdown in macrophages drives intestinal inflammation via necroptosis. Tim-3 protein and mRNA expression were assessed via double immunofluorescence staining and single-cell RNA sequencing (sc-RNA seq), respectively, in the colonic tissues of patients with inflammatory bowel disease (IBD) and healthy controls. Macrophage-specific Tim3-knockout (Tim-3M-KO) mice were generated to explore the function and mechanism of Tim-3 in dextran sodium sulfate (DSS)-induced colitis. Necroptosis was blocked by pharmacological inhibitors of receptor-interacting protein kinase (RIP)1, RIP3, and reactive oxygen species (ROS). Additionally, in vitro experiments were performed to assess the mechanisms of neutrophil necroptosis induced by Tim-3 knockdown macrophages. Although Tim-3 is relatively inactive in macrophages during colon homeostasis, it is highly active during colitis. Compared to those in controls, Tim-3M-KO mice showed increased susceptibility to colitis, higher colitis scores, and increased pro-inflammatory mediator expression. Following the administration of RIP1/RIP3 or ROS inhibitors, a significant reduction in intestinal inflammation symptoms was observed in DSS-treated Tim-3M-KO mice. Further analysis indicated the TLR4/NF-κB pathway in Tim-3 knockdown macrophages mediates the TNF-α-induced necroptosis pathway in neutrophils. Macrophage Tim-3 regulates neutrophil necroptosis via intracellular ROS signaling. Tim-3 knockdown macrophages can recruit neutrophils and induce neutrophil necroptosis, thereby damaging the intestinal mucosal barrier and triggering a vicious cycle in the development of colitis. Our results demonstrate a protective role of macrophage Tim-3 in maintaining gut homeostasis by inhibiting neutrophil necroptosis and provide novel insights into the pathogenesis of IBD.

The role of neurotransmitters in mediating the relationship between brain alterations and depressive symptoms in patients with inflammatory bowel disease

A growing body of evidence from neuroimaging studies suggests that inflammatory bowel disease (IBD) is associated with functional and structural alterations in the central nervous system and that it has a potential link to emotional symptoms, such as anxiety and depression. However, the neurochemical underpinnings of depression symptoms in IBD remain unclear. We hypothesized that changes in cortical gamma-aminobutyric acid (GABA+) and glutamine (Glx) concentrations are related to cortical thickness and resting-state functional connectivity in IBD as compared to healthy controls. To test this, we measured whole-brain cortical thickness and functional connectivity within the medial prefrontal cortex (mPFC), as well as the concentrations of neurotransmitters in the same brain region. We used the edited magnetic resonance spectroscopy (MRS) with the MEGA-PRESS sequence at a 3 T scanner to quantitate the neurotransmitter levels in the mPFC. Subjects with IBD (N = 37) and healthy control subjects (N = 32) were enrolled in the study. Compared with healthy controls, there were significantly decreased GABA+ and Glx concentrations in the mPFC of patients with IBD. The cortical thickness of patients with IBD was thin in two clusters that included the right medial orbitofrontal cortex and the right posterior cingulate cortex. A seed-based functional connectivity analysis indicated that there was higher connectivity of the mPFC with the left precuneus cortex (PC) and the posterior cingulate cortex, and conversely, lower connectivity in the left frontal pole was observed. The functional connectivity between the mPFC and the left PC was negatively correlated with the IBD questionnaire score (r = -0.388, p = 0.018). GABA+ concentrations had a negative correlation with the Hamilton Depression Scale (HAMD) score (r = -0.497, p = 0.002). Glx concentration was negatively correlated with the HAMD score (r = -0.496, p = 0.002) and positively correlated with the Short-Form McGill Pain Questionnaire score (r = 0.330, p = 0.046, uncorrected). There was a significant positive correlation between the ratio of Glx to GABA+ and the HAMD score (r = 0.428, p = 0.008). Mediation analysis revealed that GABA+ significantly mediated the main effect of the relationship between the structural and functional alterations and the severity of depression in patients with IBD. Our study provides initial evidence of neurochemistry that can be used to identify potential mechanisms underlying the modulatory effects of GABA+ on the development of depression in patients with IBD.

Differential Gene Expression of Checkpoint Markers and Cancer Markers in Mouse Models of Spontaneous Chronic Colitis

The presence of checkpoint markers in cancer cells aids in immune escape. The identification of checkpoint markers and early cancer markers is of utmost importance to gain clarity regarding the relationship between colitis and progressive inflammation leading to cancer. Herein, the gene expression levels of checkpoint makers, cancer-related pathways, and cancer genes in colon tissues of mouse models of chronic colitis (Winnie and Winnie-Prolapse mice) using next-generation sequencing are determined. Winnie mice are a result of a Muc2 missense mutation. The identification of such genes and their subsequent expression and role at the protein level would enable novel markers for the early diagnosis of cancer in IBD patients. The differentially expressed genes in the colonic transcriptome were analysed based on the Kyoto Encyclopedia of Genes and Genomes pathway. The expression of several oncogenes is associated with the severity of IBD, with Winnie-Prolapse mice expressing a large number of key genes associated with development of cancer. This research presents a number of new targets to evaluate for the development of biomarkers and therapeutics.

Ulcerative Colitis Concomitant with Cytomegalovirus Infection, Bullous Sweet's Syndrome, and Acute Myeloid Leukemia: A Case Report and Literature Review

Background

Ulcerative colitis (UC) is a chronic, relapsing progressive inflammatory immune disease. There is still no cure for it. Even worse, UC may predispose patients to opportunistic infections, and several extra-intestinal manifestations (EIMs) and comorbidities may antedate, occur with, or postdate the onset of UC, which may increase the mortality risk. But case reports of UC patients simultaneously concomitant with opportunistic infection, EIM, and comorbidity are extremely rare.

Case Presentation

We report a case of 51-year-old male patient with incipient UC accompanied by cytomegalovirus (CMV) infection and bullous Sweet's syndrome (bSS, a cutaneous EIM of UC) after treatment with oral mesalazine and prednisolone for 3 weeks. After clearance of the CMV infection by using ganciclovir, the patient was administered two cycles of infliximab to cure UC and bSS; however, he developed acute myeloid leukemia (AML) a month later and died after two cycles of chemotherapy.

Conclusion

Based on this rare case of UC concomitant with CMV infection, bSS and AML, we recommend that it is important to distinguish between an acute UC flare and opportunistic infections, especially in patients receiving immunosuppressive therapy, and monitor EIMs and comorbidities timely. Particular attention should be paid to cancer surveillance. Clinicians should be mindful of these facts to adopt optimal therapeutic options to address all aspects of UC. Early initiation of biological therapy may be of benefit to patients with newly diagnosed severe UC.

Hypoxia in the Pathophysiology of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic disease of disordered chronic inflammation in the intestines that affects many people across the world. While the disease is still being better characterized, greater progress has been made in understanding the many components that intersect in the disease. Among these components are the many pieces that compose the intestinal epithelial barrier, the various cytokines and immune cells, and the population of microbes that reside in the intestinal lumen. Since their discovery, the hypoxia-inducible factors (HIFs) have been found to play an expansive role in physiology as well as diseases such as inflammation due to their role in oxygen sensing-related gene transcription, and metabolic control. Making use of existing and developing paradigms in the immuno-gastroenterology of IBD, we summarized that hypoxic signaling plays as another component in the status and progression of IBD, which may include possible functions at the origins of inflammatory dysregulation. © 2023 American Physiological Society. Compr Physiol 13:4767-4783, 2023.

The diet-microbiota axis: a key regulator of intestinal permeability in human health and disease

The intestinal barrier orchestrates selective permeability to nutrients and metabolites while excluding noxious stimuli. Recent scientific advances establishing a causal role for the gut microbiota in human health outcomes have generated a resurgent interest toward intestinal permeability. Considering the well-established role of the gut barrier in protection against foreign antigens, there is mounting evidence for a causal link between gut permeability and the microbiome in regulating human health. However, an understanding of the dynamic host-microbiota interactions that govern intestinal barrier functions remains poorly defined. Furthermore, the system-level mechanisms by which microbiome-targeted therapies, such as probiotics and prebiotics, simultaneously promote intestinal barrier function and host health remain an area of active investigation. This review summarizes the recent advances in understanding the dynamics of intestinal permeability in human health and its integration with gut microbiota. We further summarize mechanisms by which probiotics/prebiotics influence the gut microbiota and intestinal barrier functions.

Serum and Mucosal CD30 in Pediatric Inflammatory Bowel Diseases: Useful Biomarker for Diagnosis and Disease Activity Monitoring?

BACKGROUND

Inflammatory bowel diseases (IBD) frequently manifest in pediatric age, but may have atypical clinical, histological and laboratory features. Their underlying immune pathophysiology is incompletely understood, rendering quick diagnosis followed by tailored therapy difficult. The tumor necrosis factor superfamily receptor CD30 has been proposed as a potential marker of ulcerative colitis (UC) and has also been associated with elevated Th2 helper T cells.

METHODS

A cohort of pediatric patients with UC and Crohn's disease (CD) was evaluated for serum soluble CD30 (sCD30) using ELISA and expression of CD30 and subpopulations of Th1/Th2/Th17 lymphocytes in the gastrointestinal mucosa using flow cytometry (FCM). The dataset is supported by endoscopic and microscopic activity of the disease and basic laboratory markers of inflammation.

RESULTS

The cohort consisted of 102 observations from 94 patients. sCD30 levels did not differ between patients with CD or UC. However, sCD30 levels correlated with levels of CRP, ESR, fecal calprotectin and albumin and also with clinical activity of the disease in patients with both UC and CD. FCM was not helpful in evaluation of mucosal CD30, which was lowly expressed and not associated with the diagnosis or disease activity. We show augmented Th2 and Th1/17 response in terminal ileum and right-sided colon and decreased Th1/17 response in left-sided colon of UC patients. T lymphocyte subsets were also affected by anti-TNF treatment and patients' age.

CONCLUSIONS

Neither sCD30 nor mucosal CD30 expression was helpful in differentiating between UC and CD. sCD30 seems to reflect a degree of systemic inflammation and clinical activity in IBD.

Preclinical evidence for quercetin against inflammatory bowel disease: a meta-analysis and systematic review

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic, potentially cancerous disease with limited treatment options. Quercetin may be a novel treatment for IBD. However, its efficacy and safety are unknown. Our goal was to conduct a systematic evaluation to summarize the preclinical effects of quercetin, which may help guide future studies.

METHODS

The literature was drawn from three English databases (PubMed, Embase, and Web of Science), and the quality of the included literature was assessed using the SYRCLE list (10 items). The meta-analysis was performed using STATA 15.1 software.

RESULTS

A total of 11 animal studies with 199 animals were involved. The current meta-analysis showed that quercetin could reduce histological score (HS), Disease Activity Index (DAI), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), nitric oxide(NO), malondialdehyde (MDA), myeloperoxidase (MPO) activity and increase colon length (CL), weight change degree (WCD), interleukin-10 (IL-10), glutathione (GSH), superoxide dismutase (SOD) activity and catalase (CAT) activity, which may involve anti-inflammatory, anti-oxidative stress, cytoprotective, barrier protection, flora regulation.

CONCLUSIONS

In conclusion, preclinical evidence suggests that quercetin is an ideal agent for IBD treatment. However, the validity of the findings may be compromised by the low methodological quality and the small number of studies included. There may be some discrepancies between the results of the current analysis and the real situation. More rigorous experimental designs and more comprehensive studies are needed to test the protection of quercetin against IBD.

CARD9 in neutrophils protects from colitis and controls mitochondrial metabolism and cell survival

OBJECTIVES

Inflammatory bowel disease (IBD) results from a combination of genetic predisposition, dysbiosis of the gut microbiota and environmental factors, leading to alterations in the gastrointestinal immune response and chronic inflammation. Caspase recruitment domain 9 (Card9), one of the IBD susceptibility genes, has been shown to protect against intestinal inflammation and fungal infection. However, the cell types and mechanisms involved in the CARD9 protective role against inflammation remain unknown.

DESIGN

We used dextran sulfate sodium (DSS)-induced and adoptive transfer colitis models in total and conditional CARD9 knock-out mice to uncover which cell types play a role in the CARD9 protective phenotype. The impact of Card9 deletion on neutrophil function was assessed by an in vivo model of fungal infection and various functional assays, including endpoint dilution assay, apoptosis assay by flow cytometry, proteomics and real-time bioenergetic profile analysis (Seahorse).

RESULTS

Lymphocytes are not intrinsically involved in the CARD9 protective role against colitis. CARD9 expression in neutrophils, but not in epithelial or CD11c+cells, protects against DSS-induced colitis. In the absence of CARD9, mitochondrial dysfunction increases mitochondrial reactive oxygen species production leading to the premature death of neutrophilsthrough apoptosis, especially in oxidative environment. The decreased functional neutrophils in tissues might explain the impaired containment of fungi and increased susceptibility to intestinal inflammation.

CONCLUSION

These results provide new insight into the role of CARD9 in neutrophil mitochondrial function and its involvement in intestinal inflammation, paving the way for new therapeutic strategies targeting neutrophils.

Impacts of Gut Microbiota on the Immune System and Fecal Microbiota Transplantation as a Re-Emerging Therapy for Autoimmune Diseases

The enormous and diverse population of microorganisms residing in the digestive tracts of humans and animals influence the development, regulation, and function of the immune system. Recently, the understanding of the association between autoimmune diseases and gut microbiota has been improved due to the innovation of high-throughput sequencing technologies with high resolutions. Several studies have reported perturbation of gut microbiota as one of the factors playing a role in the pathogenesis of many diseases, such as inflammatory bowel disease, recurrent diarrhea due to Clostridioides difficile infections. Restoration of healthy gut microbiota by transferring fecal material from a healthy donor to a sick recipient, called fecal microbiota transplantation (FMT), has resolved or improved symptoms of autoimmune diseases. This (re)emerging therapy was approved for the treatment of drug-resistant recurrent C. difficile infections in 2013 by the U.S. Food and Drug Administration. Numerous human and animal studies have demonstrated FMT has the potential as the next generation therapy to control autoimmune and other health problems. Alas, this new therapeutic method has limitations, including the risk of transferring antibiotic-resistant pathogens or transmission of genes from donors to recipients and/or exacerbating the conditions in some patients. Therefore, continued research is needed to elucidate the mechanisms by which gut microbiota is involved in the pathogenesis of autoimmune diseases and to improve the efficacy and optimize the preparation of FMT for different disease conditions, and to tailor FMT to meet the needs in both humans and animals. The prospect of FMT therapy includes shifting from the current practice of using the whole fecal materials to the more aesthetic transfer of selective microbial consortia assembled in vitro or using their metabolic products.

Pro-inflammatory effects of silver nanoparticles in the intestine

Nanotechnology is a promising technology of the twenty-first century, being a rapidly evolving field of research and industrial innovation widely applied in our everyday life. Silver nanoparticles (AgNP) are considered the most commercialized nanosystems worldwide, being applied in diverse sectors, from medicine to the food industry. Considering their unique physical, chemical and biological properties, AgNP have gained access into our daily life, with an exponential use in food industry, leading to an increased inevitable human oral exposure. With the growing use of AgNP, several concerns have been raised, in recent years, about their potential hazards to human health, more precisely their pro-inflammatory effects within the gastrointestinal system. Therefore a review of the literature has been undertaken to understand the pro-inflammatory potential of AgNP, after human oral exposure, in the intestine. Despite the paucity of information reported in the literature about this issue, existing studies indicate that AgNP exert a pro-inflammatory action, through generation of oxidative stress, accompanied by mitochondrial dysfunction, interference with transcription factors and production of cytokines. However, further studies are needed to elucidate the mechanistic pathways and molecular targets involved in the intestinal pro-inflammatory effects of AgNP.

Inflammatory Bowel Disease Does Not Impact Mortality but Increases Length of Hospitalization in Patients with Acute Myocardial Infarction

BACKGROUND AND AIM

Inflammatory bowel diseases (IBD) have been associated with increased risk of cardiovascular events. We aimed to investigate the outcomes of myocardial infarction (MI) in patients with IBD.

METHODS

We performed a cross-sectional study utilizing data from the Nationwide Inpatient Sample from the years 1998 to 2010. ICD-9-CM codes were used to identify patients with Crohn's disease (CD) (555.X), ulcerative colitis (UC) (556.X), and acute MI (410.X). Outcomes in patients with MI with and without IBD were compared. Univariate analysis was performed. Multivariate logistic regression was used to determine the effect of UC and CD on in-hospital MI mortality after adjusting for confounders.

RESULTS

A total of 2,629,161 MI, 3,607 UC and 3784 CD patients were analyzed. UC (odds ratio [OR], 1.12; 95% CI 0.98-1.29) and CD (OR 0.99; 95% CI 0.86-1.15) did not affect in-hospital mortality in patients with MI. There was no difference between in-hospital mortality in patients with MI with or without UC (7.75% vs. 7.05%; p = 0.25) or in patients with MI with or without CD (6.50% vs. 6.59%; p = 0.87). The length of stay (LOS) was higher in IBD patients and total charges were statistically higher in patients with UC as compared to non-IBD patients ($65,182 vs. $53,542; p < 0.001).

CONCLUSIONS

This study shows that IBD does not impact in-hospital mortality from MI. However, patients with MI with IBD have longer LOS. Patients with UC have higher total hospitalization charges than patients with MI without IBD. Further prospective studies are needed to assess the outcomes of MI in IBD patients.

Therapeutic effects of stem cells in different body systems, a novel method that is yet to gain trust: A comprehensive review

Stem cell therapy has been used to treat several types of diseases, and it is expected that its therapeutic uses shall increase as novel lines of evidence begin to appear. Furthermore, stem cells have the potential to make new tissues and organs. Thus, some scientists propose that organ transplantation will significantly rely on stem cell technology and organogenesis in the future. Stem cells and its robust potential to differentiate into specific types of cells and regenerate tissues and body organs, have been investigated by numerous clinician scientists and researchers for their therapeutic effects. Degenerative diseases in different organs have been the main target of stem cell therapy. Neurodegenerative diseases such as Alzheimer's, musculoskeletal diseases such as osteoarthritis, congenital cardiovascular diseases, and blood cell diseases such as leukemia are among the health conditions that have benefited from stem cell therapy advancements. One of the most challenging parts of the process of incorporating stem cells into clinical practice is controlling their division and differentiation potentials. Sometimes, their potential for  uncontrolled growth will make these cells tumorigenic. Another caveat in this process is the ability to control the differentiation process. While stem cells can easily differentiate into a wide variety of cells,  a paracrine effect controlled activity, being in an appropriate medium will cause abnormal differentiation leading to treatment failure. In this review, we aim to provide an overview of the therapeutic effects of stem cells in diseases of various organ systems. In order to advance this new treatment to its full potential, researchers should focus on establishing methods to control the differentiation process, while policymakers should take an active role in providing adequate facilities and equipment for these projects. Large population clinical trials are a necessary tool that will help build trust in this method. Moreover, improving social awareness about the advantages and adverse effects of stem cell therapy is required to develop a rational demand in the society, and consequently, healthcare systems should consider established stem cell-based therapeutic methods in their treatment algorithms.

The Role of Immune and Epithelial Stem Cells in Inflammatory Bowel Disease Therapy

BACKGROUND

Inflammatory Bowel Disease (IBD) is categorized as Crohn's disease (CD) and Ulcerative colitis (UC) and is characterized by chronic inflammation in the gastrointestinal (GI) tract. Relapsing symptoms, including abdominal pain, increased stool frequency, loss of appetite as well as anemia contribute to significant deterioration of quality of life. IBD treatment encompasses chemotherapy (e.g. corticosteroids, thiopurines) and biological agents (e.g. antibodies targeting tumour necrosis factor α, interleukin 12/23) and surgery. However, efficacy of these therapies is not satisfactory. Thus, scientists are looking for new options in IBD treatment that could induce and maintain remission.

OBJECTIVE

To summarize previous knowledge about role of different intestinal cells in IBD pathophysiology and application of stem cells in the IBD treatment.

RESULTS

Recent studies have emphasized an important role of innate lymphoid cells (ILCs) as well as intestinal epithelial cells (IECs) in the IBD pathophysiology suggesting that these types of cells can be new targets for IBD treatment. Moreover, last studies show that stem cells transplantation reduces inflammation in patients suffering from IBD, which are resistant to conventional therapies.

CONCLUSION

Both hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) are able to restore damaged tissue and regulate the immune system. Autologous HSCs transplantation eliminates autoreactive cells and replace them with new T-cells resulting a long-time remission. Whereas MSCs transplantation is effective therapy in one of the major complications of IBD, perianal fistulas.

Fecal microbiota transplantation for Crohn's disease: a systematic review and meta-analysis

BACKGROUND

Crohn's disease (CD) is a chronic idiopathic inflammatory intestinal disorder associated with fecal dysbiosis. Fecal microbiota transplantation (FMT) is an emerging treatment approach for CD. But its efficacy and safety remain controversial. We performed a systematic review and meta-analysis to evaluate the efficacy and safety of FMT in CD patients.

METHODS

Electronic databases were searched for studies that reported efficacy and/or safety of FMT for CD. Clinical remission was established as the primary outcome. Secondary outcome was clinical response. Odds ratios with 95% confidence intervals (CIs) were reported.

RESULTS

In all, 12 trials were included in our study. Pooled analysis showed that 0.62 (95% CI 0.48, 0.81) of CD patients achieved clinical remission and 0.79 (95% CI 0.71, 0.89) of CD patients achieved clinical response post-FMT. Sub-analyses suggested the rate of clinical remission with fresh stool FMT was higher than with frozen stool FMT (73% vs 43%; p < 0.05). Most adverse events were minor and self-resolving and no major FMT-related adverse event has been reported so far.

CONCLUSIONS

The evidence showed that FMT is an effective and safe therapy for CD. FMT may be successful because it increases the overall diversity of enteric microbiome. Additional randomized controlled studies are needed.

Inflammatory bowel disease: tri-directional relationship between microbiota, immune system and intestinal epithelium

Human gut microbiota contributes to host nutrition and metabolism, sustains intestinal cell proliferation and differentiation, and modulates host immune system. The alterations in their composition lead to severe gut disorders, including inflammatory bowel disease (IBD) or inflammatory bowel syndrome (IBS). IBD including ulcerative colitis (UC) and Crohn's disease (CD) are gamut of chronic inflammatory disorders of gut, mediated by complex interrelations among genetic, environmental, and internal factors. IBD has debateable aetiology, however in recent years, exploring the central role of a tri-directional relationship between gut microbiota, mucosal immune system, and intestinal epithelium in pathogenesis is getting the most attention. Increasing incidences and early onset explains the exponential rise in IBD burden on health-care systems. Industrialization, hypersensitivity to allergens, lifestyle, hygiene hypothesis, loss of intestinal worms, and gut microbial composition, explains this shifted rise. Hitherto, the interventions modulating gut microbiota composition, microfluidics-based in vitro gastrointestinal models, non-allergic functional foods, nutraceuticals, and faecal microbiota transplantation (FMT) from healthy donors are some of the futuristic approaches for the disease management.

Gastrointestinal complications after kidney transplantation

Gastrointestinal complications are common after renal transplantation, and they have a wide clinical spectrum, varying from diarrhoea to post-transplant inflammatory bowel disease (IBD). Chronic immunosuppression may increase the risk of post-transplant infection and medication-related injury and may also be responsible for IBD in kidney transplant re-cipients despite immunosuppression. Differentiating the various forms of post-transplant colitis is challenging, since most have similar clinical and histological features. Drug-related colitis are the most frequently encountered colitis after kidney transplantation, particularly those related to the chronic use of mycophenolate mofetil, while de novo IBDs are quite rare. This review will explore colitis after kidney transplantation, with a particular focus on different clinical and histological features, attempting to clearly identify the right treatment, thereby improving the final outcome of patients.

Mapping global research trends in stem cell therapy for inflammatory bowel disease: a bibliometric analysis from 1991 to 2019

BACKGROUND

Inflammatory bowel disease (IBD) represents a series of digestive system abnormalities and parenteral manifestations. Stem cell therapy has been regarded as a promising treatment for IBD.

METHODS

We searched Web of Science Core Collection for publications of interest from 1991 to 2019. Publication performance was analyzed using several bibliometric parameters, including Statplanet to reveal the geographic distribution of the publications, VOSviewer to identify the research landscape of hot topics, and CiteSpace to show keywords with the strongest citation bursts.

RESULTS

A total of 1230 publications were identified, of which 674 articles were analyzed further. The United States was the most productive country and Spanish researchers published the highest quality articles. At a journal level, Gastroenterology published the greatest number of articles, while articles from Gut had the highest citation number. Results from the research landscape analysis of hot topics and the top 20 terms with the strongest citation bursts indicated that animal experiments, immunocytes, intestinal epithelial cells, cytokine expression, and clinical efficacy were the main focuses of research.

CONCLUSION

Stem cell therapy for IBD is currently receiving increasing attention by researchers, with focuses on animal experiments, immunocytes, intestinal epithelial cells, cytokine expression, and clinical efficacy.

Intestinal Stem Cell Niche Defects Result in Impaired 3D Organoid Formation in Mouse Models of Crohn's Disease-like Ileitis

Intestinal epithelial barrier dysfunction is a risk factor in the pathogenesis of Crohn’s disease (CD); however, no corrective FDA-approved therapies exist. We used an enteroid (EnO)-based system in two murine models of experimental CD, SAMP1/YitFc (SAMP) and TNF^ΔARE/+ (TNF). While severely inflamed SAMP mice do not generate EnOs, “inflammation-free” SAMP mice form EnO structures with impaired morphology and reduced intestinal stem cell (ISC) and Paneth cell viability. We validated these findings in TNF mice concluding that inflammation in intestinal tissues impedes EnO generation and suppressing inflammation by steroid administration partially rescues impaired formation in SAMP mice. We generated the first high-resolution transcriptional profile of the SAMP ISC niche demonstrating that alterations in multiple key pathways contribute to niche defect and targeting them may partially rescue the phenotype. Furthermore, we correlated the defects in formation and the rescue of EnO formation to reduced viability of ISCs and Paneth cells.

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Enteroid (EnO) formation is impaired in inflammation-free SAMP mice

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SAMP EnOs maintain impaired functions ex vivo recapitulating epithelial CD defect

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Inflammation impedes EnO formation, which is partially restored by steroid treatment

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Reduced number of viable intestinal stem and Paneth cells correlate with EnO defect

Opportunistic Infections Are More Prevalent in Crohn's Disease and Ulcerative Colitis: A Large Population-Based Study

BACKGROUND

Opportunistic infections (OIs) are more common in patients with inflammatory bowel disease (IBD); however, there have been limited large-scale studies of OIs in IBD. We investigated the epidemiological characteristics of OI in Crohn's disease (CD) and ulcerative colitis (UC) using a large population-based database.

METHODS

Data were collected from a commercial database (Explorys Inc., Cleveland, OH, USA) that provided electronic health records from 26 major integrated US health care systems from 1999 to March 2018. In this data set, we identified all CD and UC patients, based on Systemized Nomenclature of Medicine-Clinical Terms. Within these cohorts, we identified a variety of OIs and compared the prevalence rate of OI in individuals with IBD with that of controls (patients in the database between March 2013 and March 2018 without the diagnosis of IBD).

RESULTS

Explorys included 153,290 patients with CD and 128,540 patients with UC between March 2013 and March 2018. The prevalence of OIs was 17.8% in CD, 19.2% in UC, and 7% in non-IBD controls. When compared with non-IBD controls, all OIs were more common in CD (prevalence ratio [PR], 2.54; 95% confidence interval [CI], 2.51-2.57) and UC (PR, 2.74; 95% CI, 2.71-2.77). Overall, viral infections were numerically more common, whereas bacterial infections had the highest PRs in CD and UC when compared with controls without IBD.

CONCLUSIONS

We found significantly higher rates of OI in IBD. Our study suggests the need for close follow-up of IBD patients to diagnose and provide vaccinations where applicable for prevention of infections.

THE INFLAMMATORY BOWEL DISEASE-FATIGUE PATIENT SELF-ASSESSMENT SCALE: TRANSLATION, CROSS-CULTURAL ADAPTATION AND PSYCHOMETRIC PROPERTIES OF THE BRAZILIAN VERSION (IBD-F BRAZIL)

BACKGROUND

Fatigue is a common symptom in patients with inflammatory bowel diseases (IBD). A translated and culturally adapted, instrument with robust psychometric for measuring fatigue in Brazilian patients with IBD is needed.

OBJECTIVE

To translate and cross-culturally adapt the inflammatory Bowel Disease Fatigue Scale (IBD-F) into Brazilian-Portuguese and to test its measurement properties in Brazilian patients with IBD.

METHODS

Data from 123 patients with IBD were collected. In addition to IBD-F, the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) was used. The measurement properties tested were: internal consistency, reproducibility (reliability and agreement), construct validity, internal and external responsiveness, and ceiling and floor effects.

RESULTS

The Brazilian-Portuguese version of the IBD-F showed excellent internal consistency (Cronbach's alpha of 0.95), excellent reproducibility (ICC=0.97) and a minimal detectable change of 6.0 points. The construct validity was demonstrated with a good correlation between the IBD-F and FACIT-F (r=- 0.46). Effect sizes used for measuring internal responsiveness were moderate among those with Crohn's (0.66) disease and low in patients with ulcerative colitis (0.24). The Brazilian-Portuguese version of the IBD-F presented with high external responsiveness for Crohn's disease (0.84) and with low external responsiveness for ulcerative colitis (0.33). The area under the curve considered for responsiveness was 0.84. Twenty-five percent of floor effects and no ceiling effect were recorded.

CONCLUSION

The Brazilian-Portuguese version of IBD-F has adequate measurement properties and its use can be recommended in clinical practice and research.

Mesenchymal stem cell-gut microbiota interaction in the repair of inflammatory bowel disease: an enhanced therapeutic effect

BACKGROUND

Several investigations affirm that, patients with inflammatory bowel disease (IBD) exhibit dysbiosis characterized by restricted biodiversity and imbalanced bacterial composition intertwined with immune dysregulation. The interaction between stem cells and gut microbiota is a novel and highly promising field that could add up to a better understanding of the gut physiology, as well as therapeutic improvement towards diseases like IBD. Through direct contact or release of products and/or metabolites, gut bacteria regulate gut homeostasis, damage repair, regeneration and differentiation of stem cells. In the same way, mesenchymal stem cells (MSCs) produce similar effects including restoration of gut-microbiome composition. BODY: We reviewed the anti-inflammatory, antimicrobial, pathogenic bacterial clearance, proliferation and tissue remodeling effects of mesenchymal stem cells (MSCs) and fecal microbiota transplantation (FMT) as separate transplants in IBD, and the outcome of the interaction between MSCs and gut microbiota.

CONCLUSION

The two therapies share several points of connection in therapeutics with enhanced functionalities in their interaction with each other. Focused investigations of MSC-gut bacteria interactions could lead to a novel discovery in therapeutics. We also anticipate an improved clinical remission rate in a combined FMT-MSC transplantation approach in IBD than the current single FMT or MSC approach.

Vaccine-Preventable Diseases in Hospitalized Patients With Inflammatory Bowel Disease: A Nationwide Cohort Analysis

BACKGROUND

Inflammatory bowel disease (IBD) entails a higher risk of infections, including those that could be prevented with immunizations. Current Advisory Committee on Immunization Practices and American College of Gastroenterology vaccine recommendations for patients with IBD are based on low levels of evidence.

METHODS

We conducted a population-based descriptive cohort study using the US National Inpatient Sample ICD-9 codes from 2012 to 2015. We measured the frequency of patients with IBD who were admitted to the hospital with a vaccine-preventable disease (VPD). Frequencies and demographics were determined and compared between patients with IBD and patients without IBD.

RESULTS

Of discharges, 596,485 (2.08%) were secondary to a VPD, and 7180 (1.2%) were found to have both a VPD and IBD (including Crohn disease and ulcerative colitis). The most common VPDs among patients with IBD were herpes zoster virus (HZV) (34.9%) and hepatitis B virus (31.6%), followed by influenza (22.1%). Pneumococcal pneumonia (9.1%) and hepatitis A virus (2.4%) were less common. Inpatients with IBD were twice as likely to have HZV when compared to non-IBD inpatients (odds ratios [OR] = 2.30 [95% CI, 2.06-2.58], P < 0.0001) This finding was consistent for every study year. Pneumococcal pneumonia [OR = 0.62 (95% CI, 0.52-0.74), P < 0.0001] and influenza [OR = 0.72 (95% CI, 0.63-0.81), P < 0.0001] were significantly lower in the IBD population. There was no difference for other VPDs.

CONCLUSIONS

HZV was the most frequent VPD in IBD inpatients. Patients with IBD have a higher rate of hospital admissions with HZV and a lower rate of pneumococcal pneumonia and influenza admissions when compared with non-IBD patients. For other VPDs, patients with IBD have the same rate of admission as the general population.

Immunohistochemical Assessment of CD30+ Lymphocytes in the Intestinal Mucosa Facilitates Diagnosis of Pediatric Ulcerative Colitis

BACKGROUND

Diagnosis of pediatric inflammatory bowel diseases (IBD) remains challenging. We aimed at the value of immunohistochemical assessment of CD30+ lymphocytes in the intestinal mucosa in differential diagnosis between pediatric Crohn's disease (CD) and ulcerative colitis (UC) and its utility as a predictor of future differentiation in patients with IBD unclassified (IBDU).

METHODS

Seventy-four treatment naive pediatric patients with IBD (33 CD, 30 UC and 11 IBDU) were enrolled into the study. Biopsy samples from six different regions (terminal ileum, cecum, ascending colon, transverse colon, descending colon and rectum) were immunohistochemically stained with anti-CD30 antibody, and the number of positive cells per one high power field was quantified.

RESULTS

Significant differences between CD and UC were found when compared total counts of CD30+ cells in median numbers, mean values and maximal numbers and also for separate counts in terminal ileum, transverse colon, descending colon and rectum. The most profound difference between CD and UC was shown for total median values of CD30+ cells and for the values in rectal localization. The difference was independent on the intensity of inflammation. A cutoff value of 2.5 CD30+ cells with sensitivity 83% and specificity 90% was found for the rectum. There was no difference between patients with CD and IBDU, but a marked difference between UC and IBDU patients was revealed.

CONCLUSION

Histopathological assessment of biopsy with rectal CD30+ count is reliable and simple method that could help in differential diagnosis among IBD subtypes in children with IBD.

Granulomatous response to invasive pulmonary aspergillosis in an immunotherapy-naive host, a maladaptive response?

Pulmonary aspergillosis causes a wide spectrum of disease, ranging from asymptomatic airway colonization to severe invasive disease, contingent on the host's immune status and underlying pulmonary anatomy. The invasive form of aspergillosis is a rare occurrence in the immunocompetent population. Nevertheless, patients with a compromised innate immune response are at greatest risk. We present a case of a patient with known Crohn's disease who developed invasive pulmonary aspergillosis. His clinical picture was further complicated by an uncommon immune response characterized by the development of granulomas encasing the Aspergillus forms found on his lung biopsy, likely representing a maladaptive response, possibly related to the effects of his granulomatous disease in the lungs. He was successfully treated with antifungal therapy and video assisted thoracoscopic surgery with placement of thoracostomy tube drainage for a parapneumonic effusion. We will discuss the factors leading to his atypical presentation and clinical outcome.

In-patient outcomes of Hematopoietic Stem Cell Transplantation in Patients with Immune Mediated Inflammatory Diseases: A Nationwide Study

The impact of underlying immune-mediated inflammatory diseases (IMID) in patients undergoing hematopoietic stem cell transplant (HSCT) is unclear. Hematopoietic cell transplantation co-morbidity index (HCT-CI) is gaining acceptance as a reliable clinical method to score pre-transplant co-morbidities. Higher HCT-CI from a co-morbid IMID implies higher NRM. However, HCT-CI integrates many IMIDs with different pathogenesis and treatment together which may lead to spurious results. We performed a cross-sectional study using Nationwide Inpatient Sample dataset from 1998 to 2011 to compare the outcomes of HSCT in patients with different co-morbid IMIDs with patients without any co-morbid IMIDs. In both our multivariate and stringent matched-pair analysis, ulcerative colitis (UC) was associated with increased mortality while rheumatoid arthritis and psoriasis were associated with lower mortality as compared to no IMID group. Furthermore, in allogeneic HSCT subgroup, UC was associated with higher mortality and psoriasis was associated with lower mortality. In conclusion, we found that depending on the type of HSCT, each IMID has a different impact on outcomes of HSCT. Furthermore, UC patients had increased mortality if they had primary sclerosing cholangitis and had a higher risk of opportunistic infections like tuberculosis and cytomegalovirus suggesting the need for increased vigilance in this cohort.

Inflammatory Bowel Disease: Updates on Molecular Targets for Biologics

Therapy for inflammatory bowel disease (IBD) has changed, with several new agents being evaluated. The era of anti-tumor necrosis factor (anti-TNF) antibody therapy saw remarkable progress in IBD therapy. Some patients, however, do not respond to anti-TNF treatment, or their response decreases over time. This phenomenon highlights the need to identify new molecular targets for therapy in IBD. The targets of new therapeutic molecules in IBD must aim to restore immune dysregulation by the inhibition of proinflammatory cytokines (TNF-α, interleukin [IL]-6, IL-13, IL-17, IL-18, and IL-21) and augmentation of the effect of anti-inflammatory cytokines (IL-10, IL-11, and transforming growth factor β) and to pursue new anti-inflammatory targets, such as regulatory T-cell therapy, Smad7 antisense, Janus-activated kinase inhibition, Toll-like receptor stimulation, leukocyte adhesion, and blockade of T-cell homing via integrins and mucosal addressin cellular adhesion molecule-1. In addition, potential molecular targets could restore mucosal barrier function and stimulate mucosal healing. Despite these potential targets, the value and clinical significance of most new molecules remain unclear, and clinical efficacy and safety must be better defined before their implementation in clinical practice. This article aims to review the promising and emerging molecular targets that could be clinically meaningful for novel therapeutic approaches.

Adipose-derived stem cells ameliorate colitis by suppression of inflammasome formation and regulation of M1-macrophage population through prostaglandin E2

Inflammatory bowel disease (IBD) is an idiopathic disease caused by a dysregulated immune response to intestinal microbes in an individual with a genetic predisposition. Therefore, alleviation of inflammation is very important to treat IBD. Mesenchymal stem cells (MSCs) have been highlighted as new candidates for treating autoimmune disease based on their immunomodulatory properties. In this study, we investigated the anti-inflammatory mechanism and therapeutic effects of adipose tissue-derived MSCs (ASCs) using THP-1 macrophages and dextran sodium sulfate (DSS)-induced mice with chronic colitis. LPS-treated THP-1 cells expressed mRNA of CD11b, an M1 macrophage marker, at day 2. However, THP-1 co-cultured with ASCs expressed mRNA of CD206, CD68, CCL18, legumain, and IL-10, markers of M2 macrophages. In THP-1 cells co-cultured with ASCs, precursor (pro)-IL-1β, Cox-2, and NLRP3 increased dramatically compared to LPS-treated THP-1 cells. Secretion of IL-1β and IL-18 was significantly inhibited by ASCs, but PGE2 production was highly increased in co-culture conditions of THP-1 and ASCs. IL-18 secretion was inhibited by PGE2 treatment, and PGE2 inhibited inflammasome complex (ASC/Cas-1/NLRP3) formation in THP-1 cells. In the DSS-induced chronic colitis model, ASCs ameliorated colitis by decreasing the total number of macrophages and the M1 macrophage population. Our results suggest that ASCs can suppress the inflammatory response by controlling the macrophage population, and ASCs may be therapeutically useful for the treatment of IBD.

Clinical utility of ustekinumab in Crohn's disease

The introduction of anti-tumor necrosis factor (TNF) therapy marked an important milestone in the management of moderate-to-severe Crohn's disease (CD). However, there remains a pressing demand for alternative therapeutic options for patients with primary nonresponse, secondary loss of response, or intolerable side effects to conventional treatment and TNF antagonists. Ustekinumab (UST) is a fully human IgG1κ monoclonal antibody that inhibits the p40 subunit shared by the proinflammatory cytokines, the interleukin (IL)-12 and -23. This blockade leads to dampening of the inflammatory cascade and differentiation of inflammatory T cells. The clinical development program for UST in CD includes dose finding Phase II (Crohn's Evaluation of Response to Ustekinumab Anti-Interleukin-12/23 for Induction [CERTIFI]) and the pivotal Phase III (UNITI) trials that demonstrated both the clinical efficacy and safety in anti-TNF-naive and anti-TNF-exposed patients. Real-world evidence has further defined the role of UST in CD management. In this review, we discuss the mechanism of action of UST, describe the results of the randomized controlled trials with this agent, and review the real-world efficacy and safety data from observational cohorts. Finally, we identify areas of future research in the IL-12/23 inflammatory pathway and discuss the positioning of this novel therapeutic option in CD treatment algorithms.

Role of DDX3 in the pathogenesis of inflammatory bowel disease

When crypt stem cells of the gastrointestinal tract become injured, the result is increased synthesis of pro-inflammatory cytokines and matrix metalloproteinases by their progeny – the colonic epithelium. Chronic inflammation of the gastrointestinal tract is a characteristic of inflammatory bowel disease, which includes Crohn’s Disease and Ulcerative Colitis. In our ongoing investigation to decipher the characteristic functions of a RNA helicase gene, DDX3, we identified high DDX3 expression by immunohistochemistry of colon biopsy samples, which included chronic/mild Morbus Crohn, active Morbus Crohn, Chronic/mild Colitis Ulcerosa and active Colitis Ulcerosa in epithelium and stromal compartments. We used a small molecule inhibitor of DDX3, RK-33, on two human colonic epithelial cell lines, HCEC1CT and HCEC2CT and found that RK-33 was able to decrease expression of MMP-1, MMP-2, MMP-3, and MMP-10. Moreover, forced differentiation of a human colonic cancer cell line, HT29, resulted in decreased DDX3 levels, indicating that DDX3 contributes to the modulation of colonic epithelium differentiation. In conclusion, our results revealed novel functions of DDX3 in inflammatory bowel disease and indicate a potential for using RK-33 as a systemic therapy to promote not only differentiation of transformed colonic epithelium but also to reduce MMP expression and thus elicit a decreased inflammatory response.

Differentiating Posttransplant Inflammatory Bowel Disease and Other Colitides in Renal Transplant Patients

Renal transplant recipients who present with gastrointestinal complaints may have symptoms related to their underlying renal disease or secondary to their immunosuppressive regimen. Immunosuppression increases patients' risk for infection and medication-induced injury, and a subset of transplant patients develop a form of inflammatory bowel disease (IBD) despite being immunosuppressed. In this study, we present the spectrum of changes in colonic biopsy histology that occur in the postrenal transplant population, with emphasis on the clinical and histologic features that may allow distinction between several common disorders. Over a 15-year period, 51 postrenal transplant patients underwent colonoscopy with biopsy. Eleven (22%) patients had infectious colitis, and 10 of these had biopsy proven acute colitis. Another 17 (33%) patients were determined to have a medication-related injury based on resolution of symptoms following drug cessation. The majority (53%) of these colonic biopsies demonstrated crypt epithelial cell apoptosis and/or architectural distortion, although 41% were histologically normal. Four (8%) patients were ultimately diagnosed with a form of IBD after exclusion of other etiologies; biopsies from these patients demonstrated chronic active colitis or enteritis with plasma cell-rich expansion of the lamina propria and basal lymphoplasmacytosis. The increased prevalence of IBD in this patient cohort (4/700) compared with that reported in the overall North American population (1 to 2/700) is in line with prior studies and is likely related to the therapeutic regimen and associated immune dysregulation that occurs in solid-organ transplant recipients. We demonstrate that a combination of clinical, endoscopic, and histologic features are useful to distinguish among causes of gastrointestinal symptoms in this high risk population.

Anti-inflammatory effects of Fagopyrum cymosum administered as a potential drug for ulcerative colitis

Fagopyrum cymosum (Trev.) Meisn (Fag), which belongs to the Polygonaceae family, has been widely used to treat inflammatory diseases. Previous studies have revealed that Fag components exhibit anti-inflammatory activities; however, their potential use in treating inflammatory bowel disease (IBD) has not been explored. In the present study, mice with 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis were used as a model of IBD. Fag extract was orally administered for 3 days following the induction of colitis and the conventional drug, salicylazosulfapyridine (SASP), was used as a control. The results revealed that Fag significantly ameliorated TNBS-induced body weight loss and colonic shortening in mice (P<0.05). Furthermore, Fag suppressed levels of proinflammatory cytokines and reduced macrophage infiltration into colonic tissues (P<0.05). To further verify the anti-inflammatory effects of Fag at the molecular level, a murine macrophage cell line, Raw264.7, was used. Nuclear translocation of nuclear factor (NF)-κB p65 and the phosphorylation of inhibitor of NF-κB (IκB) were assessed using western blotting. The results demonstrated that Fag inhibited the production of proinflammatory cytokines via inhibiting NF-κB p65 nuclear translocation and IκB phosphorylation (P<0.05). Furthermore, the clinical study results revealed that Fag had significantly fewer side effects (P<0.05) and served as a better anti-inflammatory drug for ulcerative colitis compared with SASP.

Ultrasound-guided Intracardiac Injection of Human Mesenchymal Stem Cells to Increase Homing to the Intestine for Use in Murine Models of Experimental Inflammatory Bowel Diseases

Crohn's disease (CD) is a common chronic inflammatory disease of the small and large intestines. Murine and human mesenchymal stem cells (MSCs) have immunosuppressive potential and have been shown to suppress inflammation in mouse models of intestinal inflammation, even though the route of administration can limit their homing and effectiveness ^1,3,4,5. Local application of MSCs to colonic injury models has shown greater efficacy at ameliorating inflammation in the colon. However, there is paucity of data on techniques to enhance the localization of human bone marrow-derived MSCs (hMSCs) to the small intestine, the site of inflammation in the SAMP-1/YitFc (SAMP) model of experimental Crohn's disease. This work describes a novel technique for the ultrasound-guided intracardiac injection of hMSCs in SAMP mice, a well-characterized spontaneous model of chronic intestinal inflammation. Sex- and age-matched, inflammation-free AKR/J (AKR) mice were used as controls. To analyze the biodistribution and the localization, hMSCs were transduced with a lentivirus containing a triple reporter. The triple reporter consisted of firefly luciferase (fl), for bioluminescent imaging; monomeric red fluorescent protein (mrfp), for cell sorting; and truncated herpes simplex virus thymidine kinase (ttk), for positron emission tomography (PET) imaging. The results of this study show that 24 h after the intracardiac administration, hMSCs localize in the small intestine of SAMP mice as opposed to inflammation-free AKR mice. This novel, ultrasound-guided injection of hMSCs in the left ventricle of SAMP mice ensures a high success rate of cell delivery, allowing for the rapid recovery of mice with minimal morbidity and mortality. This technique could be a useful method for the enhanced localization of MSCs in other models of small-intestinal inflammation, such as TNFΔRE⁶. Future studies will determine if the increased localization of hMSCs by intra-arterial delivery can lead to increased therapeutic efficacy.

Understanding the Cautions and Contraindications of Immunomodulator and Biologic Therapies for Use in Inflammatory Bowel Disease

Ulcerative colitis and Crohn's disease are chronic inflammatory bowel diseases for which there are no cures. These diseases are immunopathogenic, and medical treatment is centered on the temperance of a dysregulated immune response to allow mucosal healing and prevent the sequelae of fistulation and stenosis. Accordingly, the armamentarium of medications, which has expanded immensely in recent history, is not without significant infectious and neoplastic risks. Many of these untoward effects can be mitigated by screening and avoidance of contraindicated medications. This review seeks to highlight the cautions for use of immunomodulators, anticytokine, and α4-integrin antagonists. The potential adverse events are further complicated by substantial heterogeneity in disease phenotype in the inflammatory bowel disease population. Large patient registries and databases provide considerable experience and knowledge to calculate the incidence of safety outcomes. To identify rarer outcomes after prolonged therapy, more prospective studies and continued adverse event reporting will aid safe application and minimize potential harms.

Mesenchymal stem/stromal cell therapy for inflammatory bowel disease: an updated review with maintenance of remission

PURPOSE OF REVIEW

There is a need for novel therapies for inflammatory bowel diseases (IBDs) that are well tolerated and effective. Currently, mesenchymal stem/stromal cells (MSCs) are being investigated in clinical trials for treatment of IBD. In this review, we update the recently published studies with an emphasis on the long-term efficacy of MSC therapy for IBD.

RECENT FINDINGS

A cumulative body of data, including a recent phase III randomized controlled trial demonstrated excellent fistula healing in patients with refractory Crohn's perianal fistulae treated via local injections of MSCs and with a good safety profile. Follow-up studies suggest long-term efficacy of MSC therapy for complex perianal Crohn's disease fistulae; however, the efficacy decreases over time and may necessitate repeat treatment. Systemic (intravenous) therapy for luminal IBD offers a relatively well tolerated alternative but its efficacy remains unclear.

SUMMARY

Recent studies demonstrate that MSCs are well tolerated and have an excellent short-term efficacy for the management of refractory fistulizing perianal Crohn's disease. The current data suggest that its influence may 'wear off' over time. More data on larger number of patients with longer duration of follow-up in the setting of a randomized placebo controlled trial are needed to confirm these promising results. For luminal IBD, there is a need for more mechanistic studies in representative preclinical murine models, and the results of an ongoing phase III randomized controlled trial are eagerly awaited.

Animal models of inflammatory bowel disease: how useful are they really?

PURPOSE OF REVIEW

Inflammatory bowel diseases (IBDs) are idiopathic chronic relapsing disorders of the gastrointestinal tract of unknown origin, characterized by heterogeneity and a multifactorial nature of their pathogenesis. Despite the recent improved options for treatment, patients with IBD still have an impaired quality of life, and require hospitalization and surgery. This review examines the contribution of animal models to the understanding and treatment of IBD.

RECENT FINDINGS

During the last decades, a large number of experimental models of intestinal inflammation have been developed. These models have proved to be helpful tools for obtaining new insights in the pathogenesis of the disease and for the preclinical evaluation of new therapies. However, even with the development of many new animal models in recent years, there are still limitations in the study of IBD because of lack of suitable animal models to cover all the requirements of basic research and preclinical studies.

SUMMARY

There is a need for a better interpretation of the data we obtain from the study of IBD animal models, in order to better understand the underlying pathogenetic mechanisms and improve the quality of the preclinical studies, and to develop more appropriate models to cover the research requirements.

Modulation of the microbiota-gut-brain axis by probiotics in a murine model of inflammatory bowel disease

Anxiety, depression, and altered memory are associated with intestinal diseases, including inflammatory bowel disease (IBD). Understanding the link between these behavioral changes and IBD is important clinically since concomitant mood disorders often increase a patient's risk of requiring surgery and developing secondary functional gastrointestinal diseases. Anxiety-like behavior (light/dark box test) and recognition memory (novel object recognition task) were determined at the peak and during resolution of inflammation in the dextran sodium sulfate (DSS) mouse model of acute colitis. DSS (5 days) was administered via drinking water followed by 3 or 9 days of normal drinking water to assess behavior during active or resolving inflammation, respectively. Disease (weight, colon length, and histology) was assessed and the composition of the gut microbiota was characterized by using qPCR on fecal pellet DNA. In a subset of mice, pretreatment with probiotics was started 1 wk prior to commencing DSS. During active inflammation (8 days), mice demonstrated impaired recognition memory and exhibited anxiety-like behavior vs.

CONTROLS

These behavioral defects were normalized by 14 days post-DSS. Shifts in the composition of the gut microbiota were evident during active inflammation, notably as decreases in lactobacilli and segmented filamentous bacteria, which were also reversed once the disease had resolved. Administration of probiotics could prevent the behavioral defects seen in acute DSS. Taken together, our findings indicate that changes in mood and behavior are present during acute inflammation in murine IBD and associated with dysbiosis and that these outcomes can be prevented by the administration of probiotics.

Extracellular ATP mediates inflammatory responses in colitis via P2 × 7 receptor signaling

Extracellular purinergic products, particularly ATP, have recently been implicated to regulate immune cell functions and contribute to aberrant inflammatory responses of immune diseases. However, regulation of immune responses of colitis by extracellular ATP and its main receptor, P2 × 7, remains to be elucidated. In the study, we induced murine colitis by feeding mice with 4% dextran sulfate sodium (DSS), and noted dramatically heightened extracellular ATP levels in colon tissues during the progression of experimental colitis. Blockade of ATP release by carbenoxolone (CBX) treatment, or promoting ATP degradation by ATP diphosphohydrolase (apyrase), decreased extracellular ATP levels in colon tissues, attenuated DSS-induced colitis, whereas inhibition of extracellular ATP degradation by sodium metatungstate (POM-1) exacerbated tissue damage in the mice with colitis. Moreover, treatment with inhibitor of P2 × 7 receptor, A438079, decreased NFκB activation and active caspase-1 expression in lamina propria immune cells, downregulated proinflammatory cytokine production in colon tissues, and attenuated murine colitis. Collectively, these data suggest extracellular ATP participates in regulation of inflammatory responses of experimental colitis, through P2 × 7 receptor and inflammasome and NFκB signaling, which provides potential alternatives to the current clinical approaches to suppress extracellular ATP-mediated immune responsiveness.

Intestinal Behçet's Disease: A True Inflammatory Bowel Disease or Merely an Intestinal Complication of Systemic Vasculitis?

Behçet's disease (BD) is a multi-systemic inflammatory disorder of an unknown etiology and shows a chronic recurrent clinical course. When the disease involves the alimentary tract, it is called intestinal BD because of its clinical importance. Intestinal BD is more frequently reported in East Asian countries than in Western or Middle Eastern countries. While any part of the gastrointestinal tract can be involved, the most common location of intestinal BD is the ileocecal area. A few, large, deep ulcerations with discrete border are characteristic endoscopic findings of intestinal BD. Currently, there is no single gold standard test or pathognomonic finding of intestinal BD. However, recently developed novel diagnostic criteria and a disease activity index have helped in assessing intestinal BD. As intestinal BD shares a lot of characteristics with inflammatory bowel disease, including genetic background, clinical manifestations, and therapeutic strategies, distinguishing between the two diseases in clinical practice is quite difficult. However, biologic agents such as anti-tumor necrosis factor α antibody shows a considerable efficacy similar to inflammatory bowel disease cases. It is important to distinguish and treat those two disease entities separately from the standpoint of precise medicine. Clinicians should require comprehensive knowledge regarding the similarities and differences between intestinal BD and inflammatory bowel disease for making an accurate clinical decision.

Mesenchymal Stem Cell Therapy for Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Recent advances in inflammatory bowel disease (IBD) therapeutics include novel medical, surgical, and endoscopic treatments. Among these, stem cell therapy is still in its infancy, although multiple studies suggest that the immunomodulatory effect of stem cell therapy may reduce inflammation and tissue injury in patients with IBD. This review discusses the novel avenue of stem cell therapy and its potential role in the management of ulcerative colitis and Crohn's disease. We conducted a comprehensive literature search to identify studies examining the role of stem cell therapy (without conditioning and immunomodulatory regimens) in IBD. Taken together, these studies suggest a promising role for stem cell therapy in IBD although the substantial challenges, such as cost and inadequate/incomplete characterization of effect, limit their current use in clinical practice.

Stem cells for murine interstitial cells of cajal suppress cellular immunity and colitis via prostaglandin E2 secretion

BACKGROUND & AIMS

After allogeneic transplantation, murine stem cells (SCs) for interstitial cells of Cajal (ICCs), electrical pacemaker, and neuromodulator cells of the gut, were incorporated into gastric ICC networks, indicating in vivo immunosuppression. Immunosuppression is characteristic of bone marrow- and other non-gut-derived mesenchymal stem cells (MSCs), which are emerging as potential therapeutic agents against autoimmune diseases, including inflammatory bowel disease. Therefore, we investigated whether gut-derived ICC-SCs could also mitigate experimental colitis and studied the mechanisms of ICC-SC-mediated immunosuppression in relation to MSC-induced pathways.

METHODS

Isolated ICC-SCs were studied by transcriptome profiling, cytokine assays, flow cytometry, mixed lymphocyte reaction, and T-cell proliferation assay. Mice with acute and chronic colitis induced by dextran sulfate sodium and T-cell transfer, respectively, were administered ICC-SCs intraperitoneally and evaluated for disease activity by clinical and pathological assessment and for ICC-SC homing by live imaging.

RESULTS

Unlike strain-matched dermal fibroblasts, intraperitoneally administered ICC-SCs preferentially homed to the colon and reduced the severity of both acute and chronic colitis assessed by clinical and blind pathological scoring. ICC-SCs profoundly suppressed T-cell proliferation in vitro. Similar to MSCs, ICC-SCs strongly expressed cyclooxygenase 1/2 and basally secreted prostaglandin E2. Indomethacin, a cyclooxygenase inhibitor, countered the ICC-SC-mediated suppression of T-cell proliferation. In contrast, we found no role for regulatory T-cell-, programmed death receptor-, and transforming growth factor-β-mediated mechanisms reported in MSCs; and transcriptome profiling did not support a relationship between ICC-SCs and MSCs.

CONCLUSIONS

Murine ICC-SCs belong to a class different from MSCs and potently mitigate experimental colitis via prostaglandin E2-mediated immunosuppression.