IAPs and RIPK1 mediate LPS-induced cytokine production in healthy subjects and Crohn's disease

Innate immune activity fuels intestinal inflammation in Crohn's disease (CD), an inflammatory bowel disease. Identification and targeting of new molecular regulators of the innate activity are warranted to control the disease. Inhibitor of apoptosis proteins (IAPs) regulate both cell survival and inflammatory signaling. We investigated the effects of IAP inhibition by second mitochondria-derived activator of caspases (SMAC) mimetics (SMs) on innate responses and cell death to pathogen-associated molecular patterns in peripheral blood mononuclear cells (PBMCs) and monocytes. IAPs inhibited lipopolysaccharide (LPS)-induced expression of proinflammatory interleukin (IL)-1β, IL-6. Likewise, LPS (but not muramyl dipeptide or Escherichia coli) induced TNF-α was inhibited in CD and control PBMCs. The SM effect was partially reversed by inhibition of receptor-interacting serine/threonine-protein kinase 1 (RIPK1). The effect was mainly cell death independent. Thus, IAP inhibition by SMs leads to reduced production of proinflammatory cytokines and may be considered in the efforts to develop new therapeutic strategies to control CD.

Intestinal ultrasound in inflammatory bowel disease

Intestinal ultrasound (IUS) is non-invasive, fast, cheap, and well-tolerated and requires no preparation and is thus applicable as a point-of-care monitoring tool of inflammatory bowel disease (IBD). Evidence suggests that IUS is comparable to other standard monitoring modalities, i.e., endoscopy, MRI, calprotectin, and C-reactive protein and might be more accurate in predicting response to treatment at an early stage consequently allowing for timely optimised treatment. This review finds that integrating IUS as the standard of care in every IBD outpatient clinic and as the primary outcome in future medical trials seems inevitable.

Tofacitinib for Acute Severe Ulcerative Colitis: A Systematic Review

BACKGROUND

Tofacitinib has emerged as a new potential treatment for acute severe ulcerative colitis [ASUC]. We conducted a systematic review to assess efficacy, safety and integration in ASUC algorithms.

METHODS

Systematic searching was done in MEDLINE, EMBASE, Cochrane Library and Clinicaltrials.gov until August 17, 2022, including all studies reporting original observations on tofacitinib for ASUC, preferably defined according to Truelove and Witts criteria. The primary outcome was colectomy-free survival.

RESULTS

Of 1072 publications identified, 21 studies were included of which three were ongoing clinical trials. The remaining comprised a pooled cohort originating from 15 case publications [n = 42], a GETAID cohort study [n = 55], a case-control study [n = 40 cases] and a paediatric cohort [n = 11]. Of these 148 reported cases, tofacitinib was used as second-line treatment after steroid failure in previous infliximab failures or third-line after sequential steroid and infliximab or cyclosporine failure, 69 [47%] were female, median age range was 17-34 years and disease duration was 0.7-10 years. Overall, 30-day colectomy-free survival was 85% [n = 123 of 145; n = 3 without colectomy had follow-up <30 days], 90-day 86% [n = 113 of 132; n = 16 follow-up <90 days] and 180-day 69% [n = 77 of 112; n = 36 follow-up <180 days]. Tofacitinib persistence at follow-up was 68-91%, clinical remission 35-69% and endoscopic remission 55%. Adverse events occurred in 22 patients, predominantly being infectious complications other than herpes zoster [n = 13], and resulted in tofacitinib discontinuation in seven patients.

CONCLUSION

Tofacitinib appears promising for treatment of ASUC with high short-term colectomy-free survival among refractory patients who are otherwise deemed to require colectomy. However, large high-quality studies are needed.

Comparative onset of effect of biologics and small molecules in moderate-to-severe ulcerative colitis: a systematic review and network meta-analysis

BACKGROUND

Onset of effect of advanced therapies is an important parameter due to symptom load and risk of disease complications in moderate-to-severe ulcerative colitis (UC), but comparative data are lacking. Therefore, we aimed to assess the comparative onset of efficacy of biological therapies and small molecules for this patient population.

METHODS

In this systematic review and network meta-analysis, we searched MEDLINE, Embase, and Cochrane Central Register of Controlled Trials from inception to 24 August 2022, for randomised controlled trials or open-label studies assessing the efficacy of biologics or small molecule drugs within the first six weeks of treatment in adults with UC. The co-primary outcomes were the induction of clinical response and clinical remission at week 2. Network meta-analyses was conducted under the Bayesian framework. This study is registered with PROSPERO: CRD42021250236.

FINDINGS

The systematic literature search identified 20,406 citations, of which 25 studies comprising 11,074 patients fulfilled the eligibility criteria. Upadacitinib ranked highest for induction of clinical response and clinical remission at week 2 and was significantly superior to all agents but tofacitinib, which ranked second highest. Although the rankings remained consistent, no differences between upadacitinib and biological therapies were demonstrated in the sensitivity analyses of partial Mayo clinic score response or resolution of rectal bleeding at week 2. Tumor necrosis factor-α (TNF) inhibitors were significantly superior to vedolizumab and ustekinumab for patient-reported outcome-2 (PRO-2) remission at week 2 in bio-naïve patients. Filgotinib 100 mg, ustekinumab, and ozanimod ranked lowest across all endpoints.

INTERPRETATION

In this network meta-analysis, we found upadacitinib to be significantly superior to all agents but tofacitinib for the induction of clinical response and clinical remission two weeks after treatment initiation. In contrast, ustekinumab and ozanimod ranked lowest. Our findings help to establish the evidence regarding the onset of efficacy of advanced therapies.

FUNDING

None.

Novel blood-based biomarker candidates in screening for colorectal cancer

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Background: Colorectal cancer (CRC) is the third most common cancer worldwide motivating national screening strategies utilizing fecal immunochemical tests (FIT). Blood-based biomarkers could be an alternative method to increase compliance in population-based screening programs for early detection of CRC. We aimed to identify new blood-based biomarkers that could be potential candidates for use in colorectal cancer screening. Methods: In a nested cohort study of 1967 FIT positive participants of the Danish CRC screening program serum levels of GDF-15, hepsin, IL-8, keratin1-10, L1CAM, MIA, monocyte MCP-1, NSE and OPG were measured using the Luminex xMAP immunoassay platform. Main outcomes were CRC vs non-CRC and CRC, high-risk adenomas (HRA) or medium-risk adenomas (MRA) vs low-risk adenomas (LRA) or clean colorectum. Odds ratios for associations between biomarker expressions and outcomes were calculated using logistic regression models and visualized by area under the receiver operating characteristic (ROC) curve (AUC). Analyses were made on the Luminex biomarkers alone and with addition of clinical and demographic information. Results: FIT-induced colonoscopies detected 240 CRCs and 625 HRA or MRA. Multivariate analyses using all biomarkers and age found hepsin, IL-8 and OPG significantly (p<0.001) associated in relation to the main outcome (CRC vs non-CRC) with odds ratios of 0.74 [0.59-0.92], 2.59 [2.12-3.15] and 0.90 [0.82-0.99], respectively. The full model using all biomarkers and age presented an AUC of 0.73 [0.70-0.77]. Conclusions: Changed serum levels of nine novel biomarkers seem to be potential predictors for early detection of CRC, especially hepsin, IL-8 and OPG. [Table: see text]

Systematic review with meta-analysis: The impact of cancer treatments on the disease activity of inflammatory bowel diseases

BACKGROUND AND AIMS

The association between cancer treatments and exacerbation of IBD is unclear. We aimed to evaluate the effects of cancer treatments on the disease activity of IBD.

METHODS

We performed a systematic review of the literature on cancer therapy in patients with pre-existing IBD. Electronic searches of PubMed, Cochrane Library, and Embase were combined with manual searches (September 2021). Meta-analysis was performed using the random-effects model. The primary outcome was flares of IBD following cancer therapy. Secondary outcomes were need for IBD-related hospitalization, surgery, and initiation or intensification of steroid or biological treatments to manage IBD flares.

RESULTS

In total, 33 studies were included in the systematic review, comprising 1,298 patients with IBD who received cancer treatment. The overall occurrence of IBD flares following cancer treatment was 30% (95% confidence interval (CI) 23-37%). IBD flares resulted in utilization of systemic steroids and biologic therapies among 25% and 10%, respectively, and in discontinuation of cancer treatment among 14% of patients. Finally, risk of gastrointestinal toxicity following immune check point inhibitor treatment (ICI) was increased in patients with IBD compared to patients without IBD (RR=3.62 (95%CI 2.57-5.09). Despite this, the studies generally reported that flares were manageable.

CONCLUSIONS

Current data indicate a high proportion of patients with IBD experiencing a flare following the start of cancer treatment. Patients with IBD were at increased risk of gastrointestinal toxicity following ICI treatment compared to those without IBD. However, cancer therapy-induced IBD flares were manageable and should not preclude appropriate cancer treatments.

Tofacitinib and faecal microbiota transplantation in treating checkpoint inhibitor-induced enterocolitis: case report

BACKGROUND

Immune checkpoint inhibitors (ICIs) can induce a wide range of immune-related adverse events (irAEs), potentially affecting any organ. ICI-induced colitis is a frequently reported irAE, whereas enteritis is rare and not well documented.

CASE PRESENTATION

We are presenting a patient with metastatic melanoma who developed severe ICI-induced enterocolitis multirefractory for glucocorticoids, infliximab and vedolizumab, partially responding to faecal microbiota transplantation and final complete response to tofacitinib.

CONCLUSION

This case supports that tofacitinib may be an(other) effective agent in managing multirefractory ICI-induced diarrhoea caused by colitis and/or enteritis.

Early Intestinal Ultrasound Predicts Intravenous Corticosteroid Response in Hospitalised Patients With Severe Ulcerative Colitis

BACKGROUND AND AIMS

Our aim was to determine if transabdominal intestinal ultrasound changes after 48 ± 24 h of intravenous corticosteroids can predict treatment outcomes in hospitalised patients with severe ulcerative colitis.

METHODS

We performed a blinded observational multicentre study. Ultrasound parameters were assessed before treatment initiation, after 48 ± 24 h, and 6 ± 1 days. Treatment response was determined within 7 days by two outcome measures: 1] partial Mayo score reduction; 2] no administration of rescue therapy.

RESULTS

Out of 69 recruited patients, 56 were included in the final analysis, with 37 responders. The colon segment with the highest baseline bowel wall thickness was analysed, being the sigmoid in all patients. There was no difference in baseline bowel wall thickness between responders and non-responders in the partial Mayo score outcome. At 48 ± 24 h, a significant difference between responders and non-responders was identified in both absolute bowel wall thickness [median 3.1 mm vs 4.9 mm; p <0.0001], absolute reduction [-1.9 mm vs -0.2 mm; p <0.001], and relative reduction [-35.9% vs -4.1%; p <0.0001]. A ≤20% reduction had a sensitivity of 84.2% (95% confidence interval [CI] 60.4, 96.6%) and a specificity of 78.4% [61.8, 90.2%] for determining non-response [area under the curve 0.85]. In the multivariable analysis, a >20% reduction had the highest odds ratio (22.6 [4.2, 201.2]; p = 0.001) for determining response. Similar results were seen for the rescue therapy outcome.

CONCLUSIONS

Changes in bowel wall thickness, after 48 ± 24 h following intravenous corticosteroid treatment in hospitalised patients with severe ulcerative colitis, identify responders with high accuracy and might be used as an early marker to guide accelerated rescue therapy.

Inflammatory Bowel Diseases Affect the Phenotype and Disease Course of Coexisting Immune-Mediated Inflammatory Diseases: A Systematic Review With Meta-Analysis

BACKGROUND

It is unclear whether inflammatory bowel diseases (IBDs) affect the phenotype and severity of co-occurring immune-mediated inflammatory diseases (IMIDs). We aimed to investigate the characteristics of IMIDs in relation to co-occurring IBD.

METHODS

We conducted a systematic review of Medline and EMBASE databases from inception to September 2020. We identified studies reporting the phenotype, severity, or disease course of IMIDs among patients with or without co-occurring IBD. A meta-analysis was conducted using random effects models.

RESULTS

The electronic search yielded 13 220 studies that we narrowed down to 73 eligible studies for full-text review, including 42 on primary sclerosing cholangitis, 12 on axial spondyloarthropathies, and 8 studies on psoriasis. In primary sclerosing cholangitis, IBD was associated with less frequent involvement of extrahepatic bile ducts (risk ratio [RR], 0.50; 95% confidence interval [CI], 0.33-0.75), longer liver transplantation-free survival (hazard ratio, 0.70; 95% CI, 0.60-0.82), and no increased risk of cholangiocarcinoma (RR, 0.88; 95% CI, 0.59-1.31). Patients with axial spondyloarthropathies and co-occurring IBD were characterized by an increased risk of dactylitis (RR, 2.06; 95% CI, 1.24-3.42), a lower Bath Ankylosing Spondylitis Radiology Index (mean difference [MD] = -2.28; 95% CI, -3.26 to -1.30), and better Schober's test results (MD = 1.07; 95% CI, 0.64-1.49). Psoriasis and co-occurring IBD was associated with reduced disease severity (RR, 1.41; 95% CI, 1.02-1.96) and less frequent presentation in nails (RR, 0.14; 95% CI, 0.05-0.42), with no apparent impact on psoriatic arthritis (RR, 0.94; 95% CI, 0.27-3.31).

CONCLUSIONS

This systematic review with meta-analysis found IBD is associated with a distinct disease phenotype among the IMIDs investigated. Our findings emphasize the importance of multidisciplinary approaches to patients with co-occurring IMIDs and IBD.

Safety and efficacy of infliximab and corticosteroid therapy in checkpoint inhibitor-induced colitis

BACKGROUND

Cancer patients treated with immune check point inhibitors are at risk of developing severe colitis. However, the efficacy and safety of treatment of severe colitis is poorly understood.

AIMS

To explore the safety and efficacy of infliximab and corticosteroids in severe immune-mediated enterocolitis (IMC) METHOD: We performed a nationwide retrospective cohort study on 140 cancer patients treated with infliximab due to IMC in Denmark from 2011 to 2021.

RESULTS

The rate of complete remission with infliximab was 52% after one dose, increasing to 73% after two or more doses. Thirteen patients (10%) required additional treatment with vedolizumab. Patients were heavily exposed to corticosteroids and received a median accumulated dose of 3978 mg (interquartile range [IQR] 2552-6414). Age- and cancer-adjusted Cox regression analysis found that a high dose of prednisolone at start of tapering ≥75 mg/day was associated with increased mortality (HR 1.67, 1.04-2.69, p = 0.035). Patients responding to infliximab experienced an improvement of symptoms after 3 days (IQR 2-4) and complete remission after 31 days (IQR 14-61). Twenty-four percent required hospitalisation for infection during treatment for IMC, lasting 7 days (median). Secondary gastrointestinal infections occurred in 16%, with Clostridioides difficile being most common (64%). Further, 10% had a thromboembolic event during the first 90 days after infliximab treatment.

CONCLUSIONS

Infliximab led to complete resolution of symptoms in 73% of patients with IMC. High prednisolone dose at tapering was associated with increased mortality rate and a high incidence of infections and hospitalisations in patients with severe IMC. We suggest optimised infliximab treatment before escalation of steroid doses.

Disease Activity Patterns of Inflammatory Bowel Disease - A Danish Nationwide Cohort Study 1995-2018

BACKGROUND AND AIMS

Few studies have assessed the contemporary patterns of disease activity in patients with inflammatory bowel disease (IBD). We aimed to describe the disease patterns and their long-term outcomes.

METHODS

All Danish individuals with IBD between 1995 and 2018 were identified using information about IBD-related hospitalizations, surgeries, and redeemed prescriptions. The disease activity patterns for 5- and 10-year periods were assessed.

RESULTS

In incident patients with Crohn's disease (CD), severe disease activity occurred in the year of diagnosis in 80% of patients; for ulcerative colitis (UC) this figure was 75%, in addition to 3.4% of UC patients who underwent a colectomy within the first year. After 20 years of disease, the proportion of CD and UC patients in remission increased to 89% and 72%, respectively. The proportion of prevalent patients in remission each year was stable, despite the introduction of biological therapies. A decreasing activity pattern was the most common in both CD and UC patients (both 45%). The distribution of the disease activity patterns was observed to be stable over time. A quiescent disease pattern was accompanied by a significantly higher risk of intestinal cancer (HR: 3.37, 95%CI: 1.23-9.19) for CD patients, according to a Cox proportional hazards model. In UC patients, increasing disease activity (HR: 0.67, 95%CI: 0.31-1.48) was associated with an increased risk of intestinal cancer.

CONCLUSIONS

We reported the distribution of disease patterns among IBD patients. Patients with quiescent CD, as well as UC patients with chronic continuous or increasing activity, were at increased risk of developing intestinal cancer.

Vedolizumab as the first line of biologic therapy for ulcerative colitis and Crohn's disease - a systematic review with meta-analysis

BACKGROUND

The efficacy and safety of vedolizumab in bio-naïve patients with ulcerative colitis (UC) and Crohn's disease (CD) remain unknown.

AIMS

To perform a meta-analysis regarding vedolizumab as first line of biological therapy for UC or CD.

METHODS

A systematic review of Medline, EMBASE, and Cochrane databases per December 2020 was undertaken. Meta-analysis was conducted using random-effects models.

RESULTS

This systematic review identified 79 eligible studies with 4,520 and 3,494 bio-naïve patients with UC and CD, respectively, and 8,105 and 11,140 bio-exposed patients. Among bio-naïve patients with UC, a total of 40.0% (95%CI 27.0-54.0, I²=86%) and 63.9% (95%CI 47.0-79.2, I²=36%) achieved clinical remission at weeks 14 and 52, respectively. The corresponding rates in CD were 54.0% (95%CI 42.0-66.0, I²=23%), and 61.7% (95%CI 55.2-68.1, I²=0%). Bio-naïvety was associated with a higher probability of clinical remission at week 52 in UC (relative risk (RR)=1.32 (95%CI 1.14-1.53)), while this was only apparent until week 26 in CD (RR=1.60 (95%CI 1.30-1.95)). Finally, bio-naïve UC patients had a lower risk of serious adverse events (RR=0.29 (95%CI 0.09-0.95)).

CONCLUSION

Vedolizumab was found to have a favorable efficacy and safety profile in bio-naïve patients with UC and CD. The findings have implications in the management of IBD.

Outcomes and Long-Term Effects of COVID-19 in Patients with Inflammatory Bowel Diseases - A Danish Prospective Population-Based Cohort Study with Individual-Level Data

BACKGROUND AND AIMS

The health consequences of coronavirus disease 2019 [COVID-19] among patients with ulcerative colitis [UC] and Crohn's disease [CD] remain largely unknown. We aimed to investigate the outcomes and long-term effects of COVID-19 in patients with UC or CD.

METHODS

We conducted a prospective, population-based study covering all Danish patients with CD or UC and confirmed COVID-19 between January 28, 2020 and April 1, 2021, through medical records and questionnaires.

RESULTS

All 319 patients with UC and 197 patients with CD who developed COVID-19 in Denmark were included in this study and compared with the Danish background population with COVID-19 [N = 230 087]. A significantly higher risk of COVID-19-related hospitalization was observed among patients with UC (N = 46 [14.4%], relative risk [RR] = 2.49 [95% confidence interval, CI, 1.91-3.26]) and CD (N = 24 [12.2%], RR = 2.11 [95% CI 1.45-3.07]) as compared with the background population (N = 13 306 [5.8%]). A similar pattern was observed for admission to intensive care (UC: N = 8 [2.51%], RR = 27.88 [95% CI 13.88-56.00]; CD: N = 3 [1.52%], RR = 16.92 [95% CI 5.46-52.46]). After a median of 5.1 months (interquartile range [IQR] 4.5-7.9), 58 [42.3%] and 39 [45.9%] patients with UC and CD, respectively, reported persisting symptoms which were independently associated with discontinuation of immunosuppressive therapies during COVID-19 (odds ratio [OR] = 1.50 [95% CI 1.07-10.22], p = 0.01) and severe COVID-19 (OR = 2.76 [95% CI 1.05-3.90], p = 0.04), but not with age or presence of comorbidities.

CONCLUSION

In this population-based study of 516 patients with IBD and COVID-19, 13.6% needed hospitalization and 2.1% required intensive care. Furthermore, sequelae were frequent, affecting 43.7% of COVID-19-infected patients. These findings might have implications for planning the healthcare of patients in the post-COVID-19 era.

Association Between the Clinical, Biochemical, and Endoscopic Activity of Inflammatory Bowel Diseases and Severity and Long-term Outcomes of Coronavirus Disease 2019-A Population-based Study

This brief report investigated the impact of clinical, biochemical, and endoscopic activity of IBD on the severity and long-term outcomes of COVID-19 in a prospective population-based cohort. The study did not identify any association between IBD activity and COVID-19 outcomes.

Lipidomic Trajectories Characterize Delayed Mucosal Wound Healing in Quiescent Ulcerative Colitis and Identify Potential Novel Therapeutic Targets

Improving the long-term prognosis of ulcerative colitis (UC) requires sustained deep mucosal colonic healing with histologic remission, making the study of colonic tissue regeneration essential. In experimental colitis models, lipid metabolites are recognized as pivotal components of this process. This study aimed to describe the kinetics of wound healing and lipid metabolites engaged in regeneration in the normal colonic mucosa and how they are affected in UC to reveal new therapeutic targets. Experimental colonic wounds were created endoscopically in quiescent UC (n=21) and controls (n=9), and the healing process was surveilled by serial endoscopies and cross-sectional wound biopsies post-wounding. Biopsies were analyzed by liquid chromatography coupled with mass spectrometry. Endoscopic wound scores were significantly higher in UC at day two (p=0.001) and seven (p<0.0001) post-wounding, demonstrating a prolonged wound healing process. The wound scores were correlated with lipid mediators crucial for normal regeneration and sustained UC-specific changes in key phospholipids and eicosanoids, i.e., lysophosphatidylcholine, phosphatidylcholine, lysophosphatidic acid, phosphatidylglycerol, phosphatidylinositol, prostaglandin D₂, and prostaglandin E₁, were observed. A prolonged wound healing process is identified in quiescent UC with altered disease specific lipidomic trajectories providing potential novel therapeutic avenues for stimulating mucosal regeneration as an add-on to the traditional immune suppression treatment.

Vedolizumab as first-line biological therapy in elderly patients and those with contraindications for anti-TNF therapy: a real-world, nationwide cohort of patients with inflammatory bowel diseases

BACKGROUND

Data from real-life populations about vedolizumab as first-line biological therapy for ulcerative colitis (UC) and Crohn's disease (CD) are emerging.

OBJECTIVE

To investigate the efficacy and safety of vedolizumab in bio-naïve patients with UC and CD.

METHODS

A Danish nationwide cohort study was conducted between November 2014 and November 2019. Primary outcomes were clinical remission, steroid-free clinical remission, and sustained clinical remission from weeks 14 through 52.

RESULTS

The study included 56 patients (UC:31, CD:25) who initiated treatment with vedolizumab mainly because of contraindications to anti-TNFs, of whom 54.8 and 24.0%, respectively received systemic steroids at the initiation. Rates of clinical remission at weeks 6, 14, and 52 were 32.0, 48.0, and 40.0%, respectively, in UC, and 36.8, 36.8, and 47.4% in CD. Steroid-free clinical remission at week 52 was achieved among 36.0 and 47.4% of UC and CD patients, while sustained clinical remission was achieved in 32.0 and 36.8%. Lack of remission was associated with being female (68.8 vs. 11.1%, p = .01) in UC and non-structuring, non-penetrating behavior in CD (90.0 vs. 44.4%, p = .03); however, this was not confirmed in multivariate analysis. Discontinuation due to primary non-response occurred in 20.0 and 5.3% of UC and CD patients, respectively, while rates of secondary loss of response were 12.0 and 5.3% after 52 weeks of follow-up. Vedolizumab was well-tolerated as only one UC patient experienced a serious adverse event.

CONCLUSION

Vedolizumab is effective in the achievement of short-term, long-term, and steroid-free clinical remission in bio-naïve UC and CD patients.

Acute Experimental Barrier Injury Triggers Ulcerative Colitis-Specific Innate Hyperresponsiveness and Ulcerative Colitis-Type Microbiome Changes in Humans

BACKGROUND AND AIMS

The trigger hypothesis opens the possibility of anti-flare initiation therapies by stating that ulcerative colitis (UC) flares originate from inadequate responses to acute mucosal injuries. However, experimental evidence is restricted by a limited use of suitable human models. We thus aimed to investigate the acute mucosal barrier injury responses in humans with and without UC using an experimental injury model.

METHODS

A standardized mucosal break was inflicted in the sigmoid colon of 19 patients with UC in endoscopic and histological remission and 20 control subjects. Postinjury responses were assessed repeatedly by high-resolution imaging and sampling to perform Geboes scoring, RNA sequencing, and injury niche microbiota 16S ribosomal RNA gene sequencing.

RESULTS

UC patients had more severe endoscopic postinjury inflammation than did control subjects (P < .01), an elevated modified Geboes score (P < .05), a rapid induction of innate response gene sets (P < .05) and antimicrobial peptides (P < .01), and engagement of neutrophils (P < .01). Innate lymphoid cell type 3 (ILC3) markers were increased preinjury (P < .01), and ILC3 activating cytokines were highly induced postinjury, resulting in an increase in ILC3-type cytokine interleukin-17A. Across groups, the postinjury mucosal microbiome had higher bacterial load (P < .0001) and lower α-diversity (P < .05).

CONCLUSIONS

UC patients in remission respond to mucosal breaks by an innate hyperresponse engaging resident regulatory ILC3s and a subsequent adaptive activation. The postinjury inflammatory bowel disease-like microbiota diversity decrease is irrespective of diagnosis, suggesting that the dysbiosis is secondary to host injury responses. We provide a model for the study of flare initiation in the search for antitrigger-directed therapies.

CDX2 regulates interleukin-33 gene expression in intestinal epithelial cells (LS174T)

Dysregulation of interleukin-33 (IL-33) has been implicated in the pathogenesis of several autoimmune and inflammatory diseases, but few studies have examined transcriptional regulation of the IL33 gene. In the intestines, gene regulation is controlled by a transcription factor network of which the intestinal-specific transcription factor CDX2 is a key component. In this study, we investigated whether CDX2 regulates IL33 mRNA expression. We examined IL33 mRNA expression in primary colonic epithelial cells from healthy humans and epithelial cell lines, revealing high expression levels in primary colonic and LS174T cells. Combining genomics data (ChIP-seq, RNA-seq) and IL33 promoter analyses in LS174T cells revealed intronic enhancer activity in the IL33 gene that is dependent on CDX2 expression. Western blotting and qRT-PCR confirmed that IL33 expression is upregulated in a CDX2 concentration-dependent manner, thereby providing the first evidence that CDX2 regulates the expression of IL33.

Efficacy of Ustekinumab for Active Perianal Fistulizing Crohn Disease: A Double-Center Cohort Study

This double-center cohort study found a high short-term and long-term efficacy of ustekinumab for perianal fistulizing Crohn disease that was also well tolerated.

Coronavirus disease 2019, immune-mediated inflammatory diseases and immunosuppressive therapies - A Danish population-based cohort study

BACKGROUND

Limited data exist regarding the disease course of coronavirus disease 2019 (COVID-19) and its relationship with immunosuppressants among patients with immune-mediated inflammatory diseases (IMIDs). Therefore, this study aims to investigate the association between COVID-19, frequent rheumatological, dermatological, gastrointestinal, and neurological IMIDs and immunosuppressants.

METHODS

We conducted a Danish population-based cohort study including all residents living within Capital Region of Denmark and Region Zealand from January 28th, 2020 until September 15th, 2020 with the only eligibility criterion being a test for SARS-CoV-2 via reverse transcription-polymerase chain-reaction. Main outcomes included development of COVID-19, COVID-19-related hospitalization and mortality.

RESULTS

COVID-19 was less common among patients with IMIDs than the background population (n = 328/20,513 (1.60%) and n = 10,792/583,788(1.85%), p < 0.01, respectively). However, those with IMIDs had a significantly higher risk of COVID-19-related hospitalization (31.1% and 18.6%, p < 0.01, respectively) and mortality (9.8% and 4.3%, p < 0.01, respectively), which were associated with patients older than 65 years, and presence of comorbidities. Furthermore, systemic steroids were independently associated with a severe course of COVID-19 (Odds ratio (OR) = 3.56 (95%CI 1.83-7.10), p < 0.01), while biologic therapies were associated with a reduced risk hereof (OR = 0.47 (95%CI 0.22-0.95), p = 0.04). Patients suspending immunosuppressants due to COVID-19 had an increased risk of subsequent hospitalization (OR = 3.59 (95%CI 1.31-10.78), p = 0.02).

CONCLUSION

This study found a lower occurrence, but a more severe disease course, of COVID-19 among patients with IMIDs, which was associated with the use of systemic steroids for IMIDs and suspension of other immunosuppressants. This study emphasizes the importance of weighing risks before suspending immunosuppressants during COVID-19.

The Incidence and Disease Course of Perianal Crohn's Disease: A Danish Nationwide Cohort Study, 1997-2015

BACKGROUND AND AIMS

Perianal Crohn's disease [CD] places a considerable burden on patients' quality of life and is complex to treat. Despite its impact and high frequency, few studies have investigated the incidence and disease course of perianal CD. The aim of this study was to assess the incidence and disease course of perianal CD in adult patients throughout a 19-year period.

METHODS

The cohort comprised all individuals aged 18 years or older who were diagnosed with CD in Denmark between January 1, 1997, and December 31, 2015, according to the National Patient Registry [NPR].

RESULTS

A total of 1812 [19%] out of 9739 patients with CD were found to have perianal CD. Perianal fistulas were the most common manifestation, accounting for 943 [52%] cases. The incidence of perianal CD remained stable over time. Patients with perianal CD were found to have an increased risk of undergoing major abdominal surgery compared with patients without perianal CD (hazard ratio: 1.51, 95% confidence interval [CI]: 1.40 to 1.64, p <0.001) in a multivariate Cox regression analysis. The incidence rate ratios of anal and rectal cancer in perianal CD patients were 11.45 [95% CI: 4.70 to 27.91, p <0.001] and 2.29 [95% CI: 1.25 to 4.20, p = 0.006], respectively, as compared with non-IBD matched controls.

CONCLUSIONS

In this nationwide study, 19% of CD patients developed perianal disease. Patients with perianal CD were at increased risk of undergoing major surgery compared with non-perianal CD patients. The risk of anal and rectal cancer was increased in patients with perianal CD compared with non-IBD matched controls.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Efficacy of ustekinumab for active perianal fistulizing Crohn's disease: a systematic review and meta-analysis of the current literature

BACKGROUND

Although the number of biological therapies for the treatment of Crohn's disease (CD) is rapidly increasing, their efficacy in inducing healing of fistulas in perianal Crohn's disease (pCD) is practically unknown, although they occur in up to 50% of patients with CD.

OBJECTIVE

We aimed to investigate the clinical effectiveness of ustekinumab for pCD in a systemic review and meta-analysis.

METHODS

Studies describing the efficacy of ustekinumab on fistulas in pCD in PubMed and EMBASE database from inception until 22 September 2020, were assessed in a systemic review and meta-analysis. The random-effect model was applied for the meta-analysis.

RESULTS

The systematic review of the current literature yielded 2,243 studies of which nine studies with a total of 396 patients were found eligible for inclusion. The pooled proportions of patients experiencing fistula response were 41.0% (95% CI 23.9-60.6%9), I ² = 85%, 39.7% (95% CI 24.3-57.4%), I ² = 69% and 55.9% (95% CI 40.8-69.9%, I ² = 67% at weeks 8, 24, and 52, respectively. Regarding fistula remission, the pooled proportions were 17.1% (95% CI 8.1-32.7%), I ² = 45%, 17.7% (95% CI 1.8-71.9%), I ² = 68%, and 16.7% (95% CI 3.0-56.5%, I ² = 51% at week 8, 24, and 52, respectively.

CONCLUSION

In this systematic review with meta-analysis, we found a signal of efficacy of ustekinumab on fistulizing pCD, emphasizing that these patients might benefit from this therapy.

Prevalence and Outcomes of COVID-19 Among Patients With Inflammatory Bowel Disease-A Danish Prospective Population-based Cohort Study

BACKGROUND AND AIMS

As no population-based study has investigated the susceptibility and disease course of COVID-19 among patients with inflammatory bowel diseases [IBD], we aimed to investigate this topic in a population-based setting.

METHODS

Two cohorts were investigated. First, a nationwide cohort of all IBD patients diagnosed with COVID-19 was prospectively followed to investigate the disease courses of both diseases. Second, within a population-based cohort of 2.6 million Danish citizens, we identified all individuals tested for SARS-CoV-2 to determine the occurrence of COVID-19 among patients with and without IBD and other immune-mediated inflammatory diseases [IMIDs].

RESULTS

Between January 28, 2020 and June 2, 2020, a total of 76 IBD patients with COVID-19 were identified in the national cohort and prospectively followed for 35 days (interquartile range [IQR]: 25-51). A large proportion [n = 19: 25%] required a COVID-19-related hospitalisation for 7 days [IQR: 2-8.5] which was associated with being 65 years or older (odds ratio [OR] = 23].80, 95% confidence interval [CI] 6.32-89.63, p <0.01) and presence of any non-IMID comorbidity [OR = 8.12, 95% CI 2.55-25.87, p <0.01], but not use of immunomodulators [p = 0.52] or biologic therapies [p = 0.14]. In the population-based study, 8476 of 231 601 [3.7%] residents tested positive for SARS-CoV-2; however, the occurrence was significantly lower among patients with IBD [62 of the 2486 patients = 2.5%, p <0.01] and other IMIDs [531 of 16 492 patients = 3.2%, p <0.01] as compared with patients without IMIDs.

CONCLUSIONS

Patients with IMIDs, including IBD, had a significantly lower susceptibility to COVID-19 than patients without IMIDs, and neither immunosuppressive therapies nor IBD activity were associated with the disease course of COVID-19.

A fully defined 3D matrix for ex vivo expansion of human colonic organoids from biopsy tissue

Intestinal organoids have widespread research and biomedical applications, such as disease modeling, drug testing and regenerative medicine. However, the transition towards clinical use has in part been hampered by the dependency on animal tumor-derived basement membrane extracts (BMEs), which are poorly defined and ill-suited for regulatory approval due to their origin and batch-to-batch variability. In order to overcome these limitations, and to enable clinical translation, we tested the use of a fully defined hydrogel matrix, QGel CN99, to establish and expand intestinal organoids directly from human colonic biopsies. We achieved efficient de novo establishment, expansion and organoid maintenance, while also demonstrating sustained genetic stability. Additionally, we were able to preserve stemness and differentiation capacity, with transcriptomic profiles resembling normal colonic epithelium. All data proved comparable to organoids cultured in the BME-benchmark Matrigel. The application of a fully defined hydrogel, completely bypassing the use of BMEs, will drastically improve the reproducibility and scalability of organoid studies, but also advance translational applications in personalized medicine and stem cell-based regenerative therapies.

Predictors of response and disease course in patients with inflammatory bowel disease treated with biological therapy-the Danish IBD Biobank Project: protocol for a multicentre prospective cohort study

INTRODUCTION

Inflammatory bowel diseases (IBDs) are chronic diseases of unknown cause characterised by a progressive and unpredictable disease course. In the last decade, biological treatment has become a cornerstone in the treatment of IBD. However, one-in-three-to-four patients do not respond to first-line biological agents and another third of patients see their response diminish over time. This highlights an unmet need for optimising the use of biologicals and the prediction of treatment response. Considering the multifaceted nature of IBD, we hypothesise that multiomics profiling of sequential samples from single patients could facilitate the discovery of predictive biomarkers of response to biological therapy and disease course.

METHODS

This is a multicentre prospective cohort study which will enrol 840 biological-naïve patients with IBD who initiate biological therapy in a 3-year period. Primary outcomes are the occurrence of primary non-response (evaluated at weeks 14-16) and loss of response (evaluated during entire follow-up in patients who obtain partial or full response after induction period). Each patient will be followed up for their clinical data for at least 1 year or till the end of study period (up to 4 years). Blood and stool samples will be collected sequentially during the first year of biological treatment. Intestinal tissue will be sampled after 1 year of treatment and whenever an endoscopy is performed. Samples will undergo transcriptomic, proteomic and microbial DNA analyses. Omics data will be integrated with clinical data to identify a panel of predictive biomarkers of response to biological therapy and disease behaviour in patients with IBD.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Danish Ethics Committee (H-18064178). Inclusion is ongoing at three study centres and will be initiated in two additional centres. Both positive and negative study results will be disseminated through peer-reviewed journals according to Strengthening the Reporting of Observational Studies in Epidemiology guidelines, as well as presented at international conferences.

SMAC mimetics and RIPK inhibitors as therapeutics for chronic inflammatory diseases

New therapeutic approaches for chronic inflammatory diseases such as inflammatory bowel disease, rheumatoid arthritis, and psoriasis are needed because current treatments are often suboptimal in terms of both efficacy and the risks of serious adverse events. Inhibitor of apoptosis proteins (IAPs) are E3 ubiquitin ligases that inhibit cell death pathways and are themselves inhibited by second mitochondria-derived activator of caspases (SMAC). SMAC mimetics (SMs), small-molecule antagonists of IAPs, are being evaluated as cancer therapies in clinical trials. IAPs are also crucial regulators of inflammatory pathways because they influence both the activation of inflammatory genes and the induction of cell death through the receptor-interacting serine-threonine protein kinases (RIPKs), nuclear factor κB (NF-κB)-inducing kinase, and mitogen-activated protein kinases (MAPKs). Furthermore, there is an increasing interest in specifically targeting the substrates of IAP-mediated ubiquitylation, especially RIPK1, RIPK2, and RIPK3, as druggable nodes in inflammation control. Several studies have revealed an anti-inflammatory potential of RIPK inhibitors that either block inflammatory signaling or block the form of inflammatory cell death known as necroptosis. Expanding research on innate immune signaling through pattern recognition receptors that stimulate proinflammatory NF-κB and MAPK signaling may further contribute to uncovering the complex molecular roles used by IAPs and downstream RIPKs in inflammatory signaling. This may benefit and guide the development of SMs or selective RIPK inhibitors as anti-inflammatory therapeutics for various chronic inflammatory conditions.

Putative biomarkers of vedolizumab resistance and underlying inflammatory pathways involved in IBD

Objectives

Characterise the circulating inflammatory cytokine pattern among patients failing consecutive anti-tumour necrosis factor (anti-TNF) and anti-integrin treatments to identify predictors of response.

Methods

A retrospective single-centre cohort study of 28 patients with inflammatory bowel disease (IBD) receiving anti-integrin therapy (vedolizumab) subsequent to the failure of anti-TNF treatment was conducted. Blood samples were obtained immediately prior to initiation of vedolizumab therapy, and the response to treatment was evaluated after completion of the 14-week induction regimen. Multiplex ELISA was applied to quantify 47 preselected plasma proteins based on their putative involvement in the inflammatory process in IBD.

Results

Anti-TNF and vedolizumab non-responders (n=20) had significantly higher levels of circulating interleukin (IL)-6 than anti-TNF non-responders with subsequent response to vedolizumab (n=8): median 9.5 pg/mL versus 5.9 pg/mL, p<0.05. Following stratification by diagnosis, patients with Crohn's disease who failed vedolizumab therapy (n=7) had higher soluble CD40 ligand (sCD40L) than responders (n=4): 153.0 pg/mL versus 45.5 pg/mL, p<0.01; sensitivity 100% (95% CI 59% to 100%), specificity 100% (95% CI 40% to 100%). Osteocalcin was higher among patients with ulcerative colitis responding to vedolizumab (n=4) compared with those not responding (n=13): 4219 pg/mL versus 2823 pg/mL, p=0.01; sensitivity 85% (95% CI 55% to 98%), specificity 100% (95% CI 40% to 100%).

Conclusions

Patients with IBD failing vedolizumab induction and anti-TNF therapy have persistent IL-6 pathway activity, which could be a potential alternative treatment target. sCD40L, osteocalcin and the IL-6 pathway activity might be predictors for response to vedolizumab.

Characterization of the enhancer and promoter landscape of inflammatory bowel disease from human colon biopsies

Inflammatory bowel disease (IBD) is a chronic intestinal disorder, with two main types: Crohn’s disease (CD) and ulcerative colitis (UC), whose molecular pathology is not well understood. The majority of IBD-associated SNPs are located in non-coding regions and are hard to characterize since regulatory regions in IBD are not known. Here we profile transcription start sites (TSSs) and enhancers in the descending colon of 94 IBD patients and controls. IBD-upregulated promoters and enhancers are highly enriched for IBD-associated SNPs and are bound by the same transcription factors. IBD-specific TSSs are associated to genes with roles in both inflammatory cascades and gut epithelia while TSSs distinguishing UC and CD are associated to gut epithelia functions. We find that as few as 35 TSSs can distinguish active CD, UC, and controls with 85% accuracy in an independent cohort. Our data constitute a foundation for understanding the molecular pathology, gene regulation, and genetics of IBD.

Many SNPs associated with inflammatory bowel disease are located in non-coding genomic regions. Here, the authors perform CAGE-sequencing on descending colon biopsies of Crohn’s disease and ulcerative colitis patients to map transcription start sites and enhancer activity for analysis of regulatory regions.

Asymptomatic Carriers Contribute to Nosocomial Clostridium difficile Infection: A Cohort Study of 4508 Patients

BACKGROUND & AIMS

Nosocomial infections with Clostridium difficile present a considerable problem despite numerous attempts by health care workers to reduce risk of transmission. Asymptomatic carriers of C difficile can spread their infection to other patients. We investigated the effects of asymptomatic carriers on nosocomial C difficile infections.

METHODS

We performed a population-based prospective cohort study at 2 university hospitals in Denmark, screening all patients for toxigenic C difficile in the intestine upon admittance, from October 1, 2012, to January 31, 2013. Screening results were blinded to patients, staff, and researchers. Patients were followed during their hospital stay by daily registration of wards and patient rooms. The primary outcomes were rate of C difficile infection in exposed and unexposed patients and factors associated with transmission.

RESULTS

C difficile infection was detected in 2.6% of patients not exposed to carriers and in 4.6% of patients exposed to asymptomatic carriers at the ward level (odds ratio for infection if exposed to carrier, 1.79; 95% confidence interval, 1.16-2.76). Amount of exposure correlated with risk of C difficile infection, from 2.2% in the lowest quartile to 4.2% in the highest quartile of exposed patients (P = .026). Combining the load of exposure to carriers and length of stay seemed to have an additive effect on the risk of contracting C difficile.

CONCLUSIONS

In a population-based prospective cohort study in Denmark, we found that asymptomatic carriers of toxigenic C difficile in hospitals increase risk of infection in other patients.

Relation between NOD2 genotype and changes in innate signaling in Crohn's disease on mRNA and miRNA levels

Crohn’s disease is associated with an altered innate immune response of pathogenic importance. This altered response can be associated to loss-of-function polymorphisms in the NOD2 (nucleotide-binding oligomerization domain-containing protein 2) gene, but also changes in transcriptional and post-transcriptional regulatory layers, including microRNA activity. Here, we characterized the link between NOD2 genotype and inflammatory-mediated changes in innate signaling by studying transcriptional and post-transcriptional activity in response to NOD2-agonist muramyl dipeptide in monocytes from healthy controls, and Crohn’s disease patients with and without NOD2 loss-of-function polymorphisms. We measured the expression of genes and microRNAs in monocytes from these subjects after stimulation with muramyl dipeptide. Gene expression profiles mainly distinguished the actual muramyl dipeptide response, but not the genotype. A hyper-responsive phenotype was found in Crohn’s disease patients without NOD2 mutations, characterized by upregulated cytokine receptors and general downregulation of microRNA expression. Conversely, microRNA expression could identify genotype-specific differences between subject groups but exhibited little change upon muramyl dipeptide treatment. Only two microRNAs showed muramyl dipeptide-induced response, including miR-155, which was found to regulate multiple genes and whose host gene was one of the highest muramyl dipeptide responders. miR-155 was upregulated in Crohn’s disease patients with NOD2 mutations following lipopolysaccharide and Escherichia coli treatment, but the upregulation was substantially reduced upon muramyl dipeptide treatment. While Crohn’s disease patients with NOD2 mutations on average showed a reduced muramyl dipeptide response, the cohort exhibited large individual variance: a small subset had inflammatory responses almost comparable to wild-type patients on both gene and miR-155 regulatory levels.

The genetics of people with Crohn’s disease affects the molecular drivers of their dysregulated immune responses. Some individuals with Crohn’s harbor mutations in the NOD2 gene, which encodes a pathogen recognition receptor that binds to a molecule called muramyl dipeptide (MDP). To better understand how alternations in NOD2 can lead to increased susceptibility to gut inflammation, Yun Chen, Mohammad Salem and colleagues from the University of Copenhagen and Herlev Hospital, Denmark, analyzed the expression patterns of both genes and small, regulatory microRNAs in blood cells from healthy controls and from Crohn’s patients with and without NOD2 mutations. They exposed the cells to MDP, and saw that although gene acticity changed dramatically as a response, there was little difference between subjects, regardless of genetics. Conversely, microRNA expression showed genotype-specific differences that weren not impacted by MDP treatment. The findings underscore the importance of microRNAs in Crohn’s disease.

Systemic and intestinal levels of factor XIII-A: the impact of inflammation on expression in macrophage subtypes

BACKGROUND

Subunit A of coagulation factor XIII (FXIII-A) is important for clot stability and acts in the subsequent wound healing process. Loss of plasma FXIII-A has been reported after surgery, sepsis, and inflammatory conditions. In the intestinal mucosa, FXIII-A is expressed by macrophages and cellular FXIII-A has been associated with phagocytosis and migration of macrophages. The objective was to evaluate the consequences of intestinal inflammation on resident mucosal macrophages, focusing on the level and distribution of FXIII-A.

METHODS

Plasma and colonic biopsies were collected from 67 patients with ulcerative colitis and controls. Intestinal samples were stained using immunohistochemistry for FXIII-A and macrophages (CD68, CD163 and iNOS). In situ hybridization were used to assess the intestinal expression of FXIII-A. FXIII-A antigen and activity levels were measured in plasma.

RESULTS

Increased infiltration of CD68 positive macrophages in the inflamed mucosa coincided with increased extracellular deposited FXIII-A and decreased expression and intracellular protein levels of FXIII-A. A decreased proportion of FXIII-A/CD68/CD163 triple-positive macrophages was observed in inflamed mucosa, indicating a reduction of the M2 phenotype with consequent loss of FXIII-A. No induction of iNOS positive macrophages was observed. Stimulation of naïve monocytes with physiological concentrations of pro-inflammatory mediators negatively affected the expression of FXIII-A. Measurements in plasma confirmed the loss of both FXIII antigen and activity during active disease.

CONCLUSIONS

Intestinal inflammation in UC induces loss of M2 macrophages with subsequent loss of FXIII-A synthesis. The loss of cellular FXIII-A may impact migration and phagocytosis, and hence limit pathogen eradication in UC.

Will novel oral formulations change the management of inflammatory bowel disease?

INTRODUCTION

The traditional management of inflammatory bowel disease (IBD) with sulphasalazine/5-aminosalicylic acid, glucocorticoids and immunomodulators (i.e., thiopurines and methotrexate) was nearly two decades ago extended with intravenously or subcutaneously administered biologics (i.e., tumor necrosis factor inhibitors and later gut-selective integrin antagonists). However, recently, orally administered treatments with simple, well-characterized, and stable structures consisting of either small molecules or anti-sense therapy have been devised.

AREAS COVERED

This review discusses the current approaches with promising new oral drugs with distinct modes of action, including: the Janus kinase inhibitors (i.e., tofacitinib, filgotinib and peficitinib); the immunomodulatory drug (laquinimod); a small α4 antagonist (AJM300); agonists for sphingosine-phosphate receptors (i.e., ozanimod, APD334, and amiselimod), as well as anti-sense therapy (mongersen) targeting SMAD7, drugs which directly target intracellular pathways of relevance for intestinal inflammation.

EXPERT OPINION

A new avenue using easily administered oral therapies for the management of IBD is being introduced. While their place in the clinical armamentarium remains to be proven, it is likely that many of these drugs will find their place in the treatment algorithm of IBD in the next few years. Thus, we will face times in which IBD therapy will be based on significantly more tablets than prescribed today.

ATG16L1: A multifunctional susceptibility factor in Crohn disease

Genetic variations in the autophagic pathway influence genetic predispositions to Crohn disease. Autophagy, the major lysosomal pathway for degrading and recycling cytoplasmic material, constitutes an important homeostatic cellular process. Of interest, single-nucleotide polymorphisms in ATG16L1 (autophagy-related 16-like 1 [S. cerevisiae]), a key component in the autophagic response to invading pathogens, have been associated with an increased risk of developing Crohn disease. The most common and well-studied genetic variant of ATG16L1 (rs2241880; leading to a T300A conversion) exhibits a strong association with risk for developing Crohn disease. The rs2241880 variant plays a crucial role in pathogen clearance, resulting in imbalanced cytokine production, and is linked to other biological processes, such as the endoplasmic reticulum stress/unfolded protein response. In this review, we focus on the importance of ATG16L1 and its genetic variant (T300A) within the elementary biological processes linked to Crohn disease.

Impact of T300A Variant of ATG16L1 on Antibacterial Response, Risk of Culture Positive Infections, and Clinical Course of Crohn's Disease

OBJECTIVES:

Autophagy-related 16-like 1 (ATG16L1) deficiency leads to impaired cellular autophagy and bacterial degradation as well as an altered cytokine production. The single-nucleotide polymorphism rs2241880 (T300A) is associated with an increased risk for Crohn's disease (CD). ATG16L1 polymorphisms could therefore have an impact on the risk of infectious complications and disease course in CD. We examined the impact of the T300A genotype on the antibacterial response toward a panel of pathogenic bacteria in vitro, as well as clinical infectious complications in vivo and the disease course in a Danish cohort of patients with CD.

METHODS:

A total of 236 CD patients were genotyped for ATG16L1^T300A; their clinical records were reviewed, and microbial, radiological, and surgical data were scrutinized. Peripheral blood mononuclear cells (PBMCs) were isolated from healthy controls and CD patients carrying the different ATG16L1 genotypes, and the production of tumor necrosis factor (TNF)-α and interleukin (IL)-1β was measured by enzyme-linked immunosorbent assay after stimulation with a panel of pathogenic bacteria of clinical relevance for the gastrointestinal tract, e.g., enteroinvasive Escherichia coli (EIEC), Listeria monocytogenes, Salmonella typhimurium, Staphylococcus aureus, or Mycobacterium avium paratuberculosis.

RESULTS:

Fifty-seven healthy controls (15, 29, 13) and 236 patients with CD (50, 108, 78) were genotyped for the T300A ATG16L1 polymorphism (AA homozygous, GG homozygous risk variant, AG heterozygous variant, respectively). The median duration of disease was 128 months (range, 30–175). The cumulative follow-up of this cohort was 2,366 patient-years. ATG16L1 gene variations interfered with the production of IL-1β, which was significantly increased in PBMCs from GG patients in response to all tested bacteria, whereas the TNF-α production was decreased in PBMCs from GG patients stimulated with EIEC, L. monocytogenes, and S. typhimurium, but unaffected by the other bacteria tested. Moreover, the GG variant showed a nonsignificant increase in the risk of bowel resections (P=0.07) and postsurgical infections (P=0.08), whereas the risk of non-disease-related infections was unaffected by genotype in the observation period. In addition, patients with AA and AG variants had a higher frequency of complicated fistulizing disease (P=0.03) with an overall more aggravated disease course with an increased number of surgical procedures for fistulous disease from a median 6.5 operations (2.0 in GG patients; P=0.002). This risk was independent on disease phenotype (penetrating vs. non-penetrating) and immunomodulating medication.

CONCLUSIONS:

The T300A variant in patients with CD strongly increases the risk for complicated fistulizing disease, and significantly affects antibacterial responses in vitro, but the latter effect seems to have a minor role for the infectious risk in CD.

Species-specific engagement of human nucleotide oligomerization domain 2 (NOD)2 and Toll-like receptor (TLR) signalling upon intracellular bacterial infection: role of Crohn's associated NOD2 gene variants

Recognition of bacterial peptidoglycan-derived muramyl-dipeptide (MDP) by nucleotide oligomerization domain 2 (NOD2) induces crucial innate immune responses. Most bacteria carry the N-acetylated form of MDP (A-MDP) in their cell membranes, whereas N-glycolyl MDP (G-MDP) is typical for mycobacteria. Experimental murine studies have reported G-MDP to have a greater NOD2-stimulating capacity than A-MDP. As NOD2 polymorphisms are associated with Crohn's disease (CD), a link has been suggested between mycobacterial infections and CD. Thus, the aim was to investigate if NOD2 responses are dependent upon type of MDP and further to determine the role of NOD2 gene variants for the bacterial recognition in CD. The response pattern to A-MDP, G-MDP, Mycobacterium segmatis (expressing mainly G-MDP) and M. segmatisΔnamH (expressing A-MDP), Listeria monocytogenes (LM) (an A-MDP-containing bacteria) and M. avium paratuberculosis (MAP) (a G-MDP-containing bacteria associated with CD) was investigated in human peripheral blood mononuclear cells (PBMCs). A-MDP and M. segmatisΔnamH induced significantly higher tumour necrosis factor (TNF)-α protein levels in healthy wild-type NOD2 PBMCs compared with G-MDP and M. segmatis. NOD2 mutations resulted in a low tumour necrosis factor (TNF)-α protein secretion following stimulation with LM. Contrary to this, TNF-α levels were unchanged upon MAP stimulation regardless of NOD2 genotype and MAP solely activated NOD2- and Toll-like receptor (TLRs)-pathway with an enhanced production of interleukin (IL)-1β and IL-10. In conclusion, the results indicate that CD-associated NOD2 deficiencies might affect the response towards a broader array of commensal and pathogenic bacteria expressing A-MDP, whereas they attenuate the role of mycobacteria in the pathogenesis of CD.

ATG16L1: A multifunctional susceptibility factor in Crohn disease

Genetic variations in the autophagic pathway influence genetic predispositions to Crohn disease. Autophagy, the major lysosomal pathway for degrading and recycling cytoplasmic material, constitutes an important homeostatic cellular process. Of interest, single-nucleotide polymorphisms in ATG16L1 (autophagy-related 16-like 1 [S. cerevisiae]), a key component in the autophagic response to invading pathogens, have been associated with an increased risk of developing Crohn disease. The most common and well-studied genetic variant of ATG16L1 (rs2241880; leading to a T300A conversion) exhibits a strong association with risk for developing Crohn disease. The rs2241880 variant plays a crucial role in pathogen clearance, resulting in imbalanced cytokine production, and is linked to other biological processes, such as the endoplasmic reticulum stress/unfolded protein response. In this review, we focus on the importance of ATG16L1 and its genetic variant (T300A) within the elementary biological processes linked to Crohn disease.

IL-33 promotes GATA-3 polarization of gut-derived T cells in experimental and ulcerative colitis

BACKGROUND

In the respiratory mucosa, interleukin (IL)-33, has been shown to enhance T helper 2 (TH2)-type responses through the master regulatory gene GATA-3. IL-33 is upregulated in ulcerative colitis (UC), and the aim was to assess if IL-33 holds a similar key position in the shaping of the immune response in experimental colitis (piroxicam-accelerated colitis (PAC) in IL-10 (-/-) mice, dextran sodium sulfate (DSS) model) and UC.

METHODS

Colonic IL-33 expression was determined in UC (8 active UC, 8 quiescent UC, and 7 controls) and experimental colitis. Mesenteric lymph node (MesLN) T cells were isolated from PAC IL-10 (-/-) mice and stimulated with IL-33.

RESULTS

The colonic IL-33 expression was significantly upregulated all forms of colitis (P < 0.01) and correlated with disease severity score and inflammation (P < 0.001), and with GATA-3 expression levels (P < 0.01); no correlation with the TH1-specific T-bet expression was observed. MesLN T cells stimulated with IL-33 had increased GATA-3 expression, and showed an IL-33 dose-dependent increase in secreted TH2-type cytokines, whereas this effect was abolished by blocking IL-33 signaling. The non-TH2-type cytokine IL-17 was upregulated by IL-33 but in a T cell receptor dependent manner, as opposed to TH2-type cytokines, which required only IL-33 stimulation.

CONCLUSIONS

The study demonstrates that intestinal IL-33 is capable of inducing GATA-3 in mucosal T cells, and suggests that IL-33 is a key mediator of pathological TH2 and non-TH2-type responses in intestinal inflammation. Blocking IL-33 signaling could be a feasible option in the treatment of UC.

Cellular inhibitor of apoptosis protein 2 controls human colonic epithelial restitution, migration, and Rac1 activation

Identification of pathways involved in wound healing is important for understanding the pathogenesis of various intestinal diseases. Cellular inhibitor of apoptosis protein 2 (cIAP2) regulates proliferation and migration in nonepithelial cells and is expressed in human colonocytes. The aim of the study was to investigate the role of cIAP2 for wound healing in the normal human colon. Wound tissue was generated by taking rectosigmoidal biopsies across an experimental ulcer in healthy subjects after 5, 24, and 48 h. In experimental ulcers, the expression of cIAP2 in regenerating intestinal epithelial cells (IECs) was increased at the wound edge after 24 h (P < 0.05), returned to normal after reepithelialization, and correlated with the inflammatory reaction in the experimental wounds (P < 0.001). cIAP2 was induced in vitro in regenerating Caco2 IECs after wound infliction (P < 0.01). Knockdown of cIAP2 caused a substantial impairment of the IEC regeneration through inhibition of migration (P < 0.005). cIAP2 overexpression lead to formation of migrating IECs and upregulation of expression of RhoA and Rac1 as well as GTP-activation of Rac1. Transforming growth factor-β1 enhanced the expression of cIAP2 but was not upregulated in wounds in vivo and in vitro. NF-κB and MAPK pathways did not affect cIAP2 expression. cIAP2 is in conclusion a regulator of human intestinal wound healing through enhanced migration along with activation of Rac1, and the findings suggest that cIAP2 could be a future therapeutic target to improve intestinal wound healing.

Identification of TNF-α-responsive promoters and enhancers in the intestinal epithelial cell model Caco-2

The Caco-2 cell line is one of the most important in vitro models for enterocytes, and is used to study drug absorption and disease, including inflammatory bowel disease and cancer. In order to use the model optimally, it is necessary to map its functional entities. In this study, we have generated genome-wide maps of active transcription start sites (TSSs), and active enhancers in Caco-2 cells with or without tumour necrosis factor (TNF)-α stimulation to mimic an inflammatory state. We found 520 promoters that significantly changed their usage level upon TNF-α stimulation; of these, 52% are not annotated. A subset of these has the potential to confer change in protein function due to protein domain exclusion. Moreover, we locate 890 transcribed enhancer candidates, where ∼50% are changing in usage after TNF-α stimulation. These enhancers share motif enrichments with similarly responding gene promoters. As a case example, we characterize an enhancer regulating the laminin-5 γ2-chain (LAMC2) gene by nuclear factor (NF)-κB binding. This report is the first to present comprehensive TSS and enhancer maps over Caco-2 cells, and highlights many novel inflammation-specific promoters and enhancers.

miR-20b, miR-98, miR-125b-1*, and let-7e* as new potential diagnostic biomarkers in ulcerative colitis

AIM: To use microarray-based miRNA profiling of colonic mucosal biopsies from patients with ulcerative colitis (UC), Crohn’s disease (CD), and controls in order to identify new potential miRNA biomarkers in inflammatory bowel disease.

METHODS: Colonic mucosal pinch biopsies from the descending part were obtained endoscopically from patients with active UC or CD, quiescent UC or CD, as well as healthy controls. Total RNA was isolated and miRNA expression assessed using the miRNA microarray Geniom Biochip miRNA Homo sapiens (Febit GmbH, Heidelberg, Germany). Data analysis was carried out by principal component analysis and projection to latent structure-discriminant analysis using the SIMCA-P+12 software package (Umetrics, Umea, Sweden). The microarray data were subsequently validated by quantitative real-time polymerase chain reaction (qPCR) performed on colonic tissue samples from active UC patients (n = 20), patients with quiescent UC (n = 19), and healthy controls (n = 20). The qPCR results were analyzed with Mann-Whitney U test. In silico prediction analysis were performed to identify potential miRNA target genes and the predicted miRNA targets were then compared with all UC associated susceptibility genes reported in the literature.

RESULTS: The colonic mucosal miRNA transcriptome differs significantly between UC and controls, UC and CD, as well as between UC patients with mucosal inflammation and those without. However, no clear differences in the transcriptome of patients with CD and controls were found. The miRNAs with the strongest differential power were identified (miR-20b, miR-99a, miR-203, miR-26b, and miR-98) and found to be up-regulated more than a 10-fold in active UC as compared to quiescent UC, CD, and controls. Two miRNAs, miR-125b-1* and let-7e*, were up-regulated more than 5-fold in quiescent UC compared to active UC, CD, and controls. Four of the seven miRNAs (miR-20b, miR-98, miR-125b-1*, and let-7e*) were validated by qPCR and found to be specifically upregulated in patients with UC. Using in silico analysis we found several predicted pro-inflammatory target genes involved in various pathways, such as mitogen-activated protein kinase and cytokine signaling, which are both key signaling pathways in UC.

CONCLUSION: The present study provides the first evidence that miR-20b, miR-98, miR-125b-1*, and let-7e* are deregulated in patients with UC. The level of these miRNAs may serve as new potential biomarkers for this chronic disease.

Tissue-regenerating functions of coagulation factor XIII

The protransglutaminase factor XIII (FXIII) has recently attracted attention within the field of tissue regeneration, as it has been found that FXIII significantly influences wound healing by exerting a multitude of functions. It supports hemostasis by enhancing platelet adhesion to damaged endothelium, and by its cross-linking activity it stabilizes the formed fibrin clot. Furthermore, FXIII limits bacterial dissemination from the wound and incorporates macromolecules of importance for cellular infiltration, supporting cell migration and survival. FXIII-mediated complex formation of the vascular endothelial growth factor receptor 2 and αV β3 integrin is important for angiogenesis, supporting the formation of granulation tissue. Chronic inflammatory conditions involving bleeding and activation of the coagulation cascade have been shown to lead to reduced FXIII levels in plasma. Of particular importance for this review is the fact that patients suffering from inflammatory bowel disease (IBD) have reduced FXIII antigen levels and activity. Furthermore, these patients show impaired mucosal healing, which supports the inflammatory state of the disease. This review summarizes the role of FXIII in the healing of wounds, and briefly summarizes the previous use of FXIII in clinical settings. Moreover, it addresses the potential role for FXIII as a therapeutic agent in the healing of persistent wounds during chronic conditions, with an emphasis on IBD.

Biological treatment of Crohn's disease

Introduction of biological agents for the treatment of Crohn's disease (CD) has led to a transformation of the treatment paradigm. Several biological compounds have been approved for patients with CD refractory to conventional treatment: infliximab, adalimumab and certolizumab pegol (and natalizumab in several countries outside the European Union). However, despite the use of biologics for more than a decade, questions still remain about the true efficacy and the best treatment regimens - especially about when to discontinue treatment. Furthermore, a need for optimizing treatment with biologics still exists, as 20-40% of patients with CD (depending on selection criteria) do not have any relevant response to the current biological agents (i.e. primary failures). A better patient selection might maximize the clinical outcome while minimizing the complications associated with this type of therapy. However, the clinical tools capable of identifying such patients are still unavailable, and the trough level strategy may help the clinician to optimize therapy and to avoid loss of response and/or immunogenicity (i.e. a low but measurable antibody level exists just before the periodic administration of the biological agent). On the other hand, peak levels and average levels should not exceed concentrations associated with increased toxicity. Randomized, controlled studies focusing on trough levels and antibodies towards the biological agent in routine clinical situations may add important pieces to the puzzle for a more rational treatment algorithm of CD patients. In some situations, the risks (i.e. immunogenicity, serious infections and the promotion of neoplasia) may, however, not outweigh the benefits of biological treatment.

MicroRNAs in inflammatory bowel disease - pathogenesis, diagnostics and therapeutics

The pathogenesis of inflammatory bowel disease (IBD) is complex and largely unknown. Until recently, research has focused on the study of protein regulators in inflammation to reveal the cellular and molecular networks in the pathogenesis of IBD. However, in the last few years, new and promising insights have been generated from studies describing an association between an altered expression of a specific class of non-coding RNAs, called microRNAs (miRs or miRNAs) and IBD. The short (approximately 22 nucleotides), endogenous, single-stranded RNAs are evolutionary conserved in animals and plants, and regulate specific target mRNAs at the post-transcriptional level. MiRNAs are involved in several biological processes, including development, cell differentiation, proliferation and apoptosis. Furthermore, it is estimated that miRNAs may be responsible for regulating the expression of nearly one-third of the genes in the human genome. Thus, miRNA deregulation often results in an impaired cellular function, and a disturbance of downstream gene regulation and signaling cascades, suggesting their implication in disease etiology. Despite the identification of more than 1900 mature human miRNAs, very little is known about their biological functions and functional targets. Recent studies have identified dysregulated miRNAs in tissue samples of IBD patients and have demonstrated similar differences in circulating miRNAs in the serum of IBD patients. Thus, there is great promise that miRNAs will aid in the early diagnosis of IBD, and in the development of personalized therapies. Here, we provide a short review of the current state-of-the-art of miRNAs in IBD pathogenesis, diagnostics and therapeutics.

Outcome after discontinuation of infliximab in patients with inflammatory bowel disease in clinical remission: an observational Danish single center study

OBJECTIVE

To investigate duration of remission, including risk factors for relapse and response to retreatment with infliximab (IFX), in patients with Crohn's disease (CD) and ulcerative colitis (UC) who had discontinued IFX while in clinical remission.

METHODS

Observational, single-center, retrospective study of all patients with a primary response to IFX who discontinued IFX therapy while in steroid-free remission. Relapse was defined as reintroduction of treatment with a biologic, systemic steroid or surgery.

RESULTS

Of 219, 53 (24%) CD patients, and 28 of 97 (30%) UC patients discontinued IFX while in clinical steroid-free remission. The proportion of patients in remission declined steadily with 61% of CD patients, and 75% of UC patients being in remission after 1 year. Half the patients maintained remission after median 2 years (680 days (412-948)) and 3.5 years (1334 days (995-1673)), respectively; p = 0.057. Twelve percent with CD and 40% with UC were in remission at the end of follow-up after 10 and 4.5 years, respectively. Longer disease duration was associated with relapse in univariate analysis in CD, OR 1.1 (1.0-1.1), p = 0.022. Of 25, 24 CD patients (96%), and 5 of 7 UC patients (71%) experienced complete clinical remission when retreated with IFX after relapse.

CONCLUSION

While the short-term prognosis seems favorable, the majority of patients who discontinue IFX while in remission relapse over time. The response to retreatment with IFX at relapse seems favorable in this subpopulation.