Interleukin-35 and Interleukin-37 anti-inflammatory effect on inflammatory bowel disease: Application of non-coding RNAs in IBD therapy

Inflammatory bowel disease (IBD) is a widespread autoimmune disease that may even be life-threatening. IBD is divided into two major subtypes: ulcerative colitis and Crohn's disease. Interleukin (IL)-35 and IL-37 are anti-inflammatory cytokines that belong to IL-12 and IL-1 families, respectively. Their recruitment relieves inflammation in various autoimmune diseases, including psoriasis, multiple sclerosis, rheumatoid arthritis, and IBD. Regulatory T cells (Tregs) and regulatory B cells (Bregs) are the primary producers of IL-35/IL-37. IL-35 and IL-37 orchestrate the regulation of the immune system through two main strategies: Blocking nuclear transcription factor kappa-B (NF-kB) and mitogen-activated protein kinase (MAPK) signaling pathways or promoting the proliferation of Tregs and Bregs. Moreover, IL-35 and IL-37 can also inhibit inflammation by adjusting the T helper (Th)17/Treg ratio balance. Among the anti-inflammatory cytokines, IL-35 and IL-37 have significant potential to reduce intestinal inflammation. Therefore, administering IL-35/IL-37-based drugs or blocking their inhibitor microRNAs could be a promising approach to alleviate IBD symptoms. Overall, in this review article, we summarized the therapeutic application of IL-35 and IL-37 in both human and experimental models of IBD. Also, it is hoped that this practical information will reach beyond IBD therapy and shed some light on treating all intestinal inflammations.

Gut community alterations associated with Clostridioides difficile colonization in hospitalized gastroenterological patients with or without inflammatory bowel disease

Clostridioides difficile colonization and development of infection commonly occur in inflammatory bowel disease (IBD) patients and can trigger flare-ups. Both conditions are inherently linked to disrupted gut microbiota. This study included 149 hospitalized gastrointestinal patients, which were divided into IBD (n = 48) and non-IBD patients (n = 101). Patients were tested for C. difficile colonization (qPCR and selective plating), and gut bacterial communities were analyzed with 16S amplicon sequencing. Blood test results were retrospectively collected from the medical records. IBD and non-IBD patients had comparable C. difficile colonization rates (31.7 and 33.3%, respectively). Compared to non-IBD C. difficile-non-colonized patients, IBD and C. difficile-colonized patients shared multiple common bacterial community characteristics including decreased diversity and reduced abundance of strict anaerobic bacteria. Furthermore, certain microbiota alterations were enhanced when IBD was accompanied by C. difficile colonization, indicating a synergistic effect between both medical complications. Conversely, certain microbial patterns were specific to C. difficile colonization, e.g., co-occurrence with Enterococcus, which was most common in IBD patients (81.3%).

Trends in Morbidity and Mortality Following Colectomy Among Patients with Ulcerative Colitis in the Biologic Era (2002-2013): A Study Using the National Inpatient Sample

BACKGROUND

Total abdominal colectomy (TAC) is a treatment modality of last recourse for patients with severe and/or refractory ulcerative colitis (UC). The goal of this study is to evaluate temporal trends and treatment outcomes following TAC among hospitalized UC patients in the biologic era.

METHODS

We queried the National Inpatient Sample (NIS) to identify patients older than 18 years with a primary diagnosis of ulcerative colitis (UC) who underwent TAC between 2002 and 2013. We evaluated postoperative morbidity and mortality as outcomes of interest. Logistic regression was used to explore factors associated with postoperative morbidity and mortality after TAC.

RESULTS

A weighted total of 307,799 UC hospitalizations were identified. Of these, 27,853 (9%) resulted in TAC. Between 2002 and 2013, hospitalizations for UC increased by over 70%; however, TAC rates dropped significantly from 111.1 to 77.1 colectomies per 1000 UC admissions. Overall, 2.2% of patients died after TAC. Mortality rates after TAC decreased from 3.5% in 2002 to 1.4% in 2013. Conversely, morbidity rates were stable throughout the study period. UC patients with emergent admissions, higher comorbidity scores and who had TAC in low volume colectomy hospitals had poorer outcomes. Regardless of admission type, outcomes were worse if TAC was performed more than 24 h after admission.

CONCLUSIONS

Despite increased hospitalizations for UC, rates of TAC have declined during the post-biologic era. For UC patients who undergo TAC, mortality has declined significantly while morbidity remains stable. Older age, race, emergent admissions and delayed surgery are predictive factors of both postoperative morbidity and mortality.

The Juncture Between Clostridioides difficile Infection and Inflammatory Bowel Diseases

The detection of Clostridioides difficile in inflammatory bowel disease (IBD) patients is a common occurrence, in part due to the standard clinical practice of testing for the presence of C. difficile during acute IBD exacerbations. Given the clinical overlap between C. difficile infections and acute IBD exacerbations (ie, increased frequency of loose stools, abdominal pain), it is hard to differentiate C. difficile infections versus colonizations in patients with underlying IBD who test positive for C. difficile. Here, we review the epidemiology, clinical presentation, risk factors, diagnosis, treatment, and outcomes of IBD patients with positive C. difficile tests.

A new target for the treatment of inflammatory bowel disease: Interleukin-37

Interleukin (IL)-37 belongs to the IL-1 cytokine family. It has anti-inflammatory effects on numerous autoimmune diseases such as asthma, psoriasis, inflammatory bowel disease (IBD), systemic lupus erythematosus (SLE), multiple sclerosis (MS) and rheumatoid arthritis (RA). Mechanistically, IL-37 plays an anti-inflammatory role by regulating the expression of inflammatory factors in two ways: binding extracellular receptors IL-18R or transferring into the nucleus with Smad3. IBD is a kind of idiopathic intestinal inflammatory disease with unknown etiology and pathogenesis. Recent researches had proved that IL-37 is negatively involved in the pathogenesis and development of IBD. Among various inflammatory diseases, IL-37 has been shown to regulate inflammatory development by acting on various immune cells such as neutrophils, macrophages (Mϕ), dendritic cells (DCs), T cells and intestinal epithelial cells. This review summarizes the biological role of IL-37, and its immunoregulatory effects on the immune cells, especially anti-inflammatory function in both human and experimental models of IBD.

Prevalence of Clostridium difficile infection among hospitalized inflammatory bowel disease patients in Greece

BACKGROUND

Inflammatory bowel disease (IBD) is an independent risk factor for Clostridium difficile infection (CDI), which is associated significantly with disease severity. We aimed to determine the rates of CDI among hospitalized IBD patients in major tertiary referral hospitals in Greece.

PATIENTS AND METHODS

A retrospective analysis was carried out of stool cultures from hospitalized patients investigated for diarrhea, during 2016, tested for CDI with glutamate dehydrogenase (GDH) and toxins A and B.

RESULTS

In total, 6932 patients were tested for CDI; 894 were positive for GDH (12.89%) and 339 were also positive for C. difficile toxin (4.89%). The prevalence of CDI among all hospitalized patients was 1.6/1000 patient-days. Among these, there were 401 IBD patients, and 62 were positive for GDH (15.46%) and 30 were also positive for C. difficile toxin (7.48%). The prevalence of CDI in IBD patients was 2.5/1000 patient-days, significantly higher than in non-IBD hospitalized patients (30/401 vs. 309/6531, P=0.013). Among the 30 IBD patients (ulcerative colitis=18, Crohn's disease=12) with CDI, six were receiving biologics, three were on corticosteroids [one combined with azathioprine (AZA) and one combined with 5-ASA], nine were on AZA monotherapy and 12 were on 5-ASA monotherapy. The prevalence of CDI among patients receiving AZA monotherapy was significantly higher than in patients receiving other medications (9/68 vs. 21/333, P=0.047). Mild CDI (n=28) was treated with metronidazole and/or vancomycin, whereas severe CDI (n=2) was treated with vancomycin.

CONCLUSION

The prevalence of CDI is higher in hospitalized IBD patients than those without IBD and AZA monotherapy increases the risk of CDI.

Time-resolved transcriptome analysis of Clostridium difficile R20291 response to cysteine

The incidence of Clostridium difficile infection has been steadily rising over the past decade. The increase in the rate of incidence is associated with the specific NAP1/BI/027 strains which are "hypervirulent" and have led to several large outbreaks since their emergence. However, the relation between these outbreaks and virulence regulation mechanisms remains unclear. It has been reported that the major virulence factor TcdA and TcdB in C. difficile could be repressed by cysteine. Here, we investigated the functional and virulence-associated regulation of C. difficile R20291 response to cysteine by using a time-resolved genome-wide transcriptome analysis. Dramatic changes of gene expression in C. difficile revealed functional processes related to transport, metabolism, and regulators in the presence of cysteine during different phases of growth. Flagellar and ribosomal genes were significantly down-regulated in long-term response to cysteine. Many NAP1/BI/027- specific genes were also modulated by cysteine. In addition, cdsB inactivation in C. difficile R20291 could remove the repression of toxin synthesis but could not remove the repression of butyrate production in the presence of cysteine. This suggests that toxin synthesis and butyrate production might have different regulatory controls in response to cysteine. Altogether, our research provides important insights into the regulatory mechanisms of C. difficile response to cysteine.

Influence of Microbiota on Intestinal Immune System in Ulcerative Colitis and Its Intervention

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) with chronic and recurrent characteristics caused by multiple reasons. Although the pathogenic factors have not been clarified yet, recent studies have demonstrated that intestinal microbiota plays a major role in UC, especially in the immune system. This review focuses on the description of several major microbiota communities that affect UC and their interactions with the host. In this review, eight kinds of microbiota that are highly related to IBD, including Faecalibacterium prausnitzii, Clostridium clusters IV and XIVa, Bacteroides, Roseburia species, Eubacterium rectale, Escherichia coli, Fusobacterium, and Candida albicans are demonstrated on the changes in amount and roles in the onset and progression of IBD. In addition, potential therapeutic targets for UC involved in the regulation of microbiota, including NLRPs, vitamin D receptor as well as secreted proteins, are discussed in this review.