NLRP3 Inhibition Leads to Impaired Mucosal Fibroblast Function in Patients with Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Inflammatory bowel diseases (IBD) are characterized by mucosal inflammation and sequential fibrosis formation, but the exact role of the hyperactive NLRP3 inflammasome in these processes is unclear. Thus, we studied the expression and function of the NLRP3 inflammasome in the context of inflammation and fibrosis in IBD.

METHODS

We analysed intestinal NLRP3 expression in mucosal immune cells and fibroblasts from IBD patients and NLRP3-associated gene expression via single-cell RNA sequencing and microarray analyses. Furthermore, cytokine secretion of NLRP3 inhibitor treated blood and mucosal cells, as well as proliferation, collagen production, and cell death of NLRP3 inhibitor treated intestinal fibroblasts from IBD patients were studied.

RESULTS

We found increased NLRP3 expression in the inflamed mucosa of IBD patients and NLRP3 inhibition led to reduced IL-1β and IL-18 production in blood cells and diminished the bioactive form of mucosal IL-1β. Single cell analysis identified overlapping expression patterns of NLRP3 and IL-1β in classically activated intestinal macrophages and we also detected NLRP3 expression in CD163+ macrophages. In addition, NLRP3 expression was also found in intestinal fibroblasts from IBD patients. Inhibition of NLRP3 led to reduced proliferation of intestinal fibroblasts, which was associated with a marked decrease in production of collagen type I and type VI in IBD patients. Moreover, NLRP3 inhibition in intestinal fibroblasts induced autophagy, a cellular process involved in collagen degradation.

CONCLUSIONS

In the presented study, we demonstrate that inhibiting NLRP3 might pave the way for novel therapeutic approaches in IBD, especially to prevent the severe complication of intestinal fibrosis formation.

IL-20 controls resolution of experimental colitis by regulating epithelial IFN/STAT2 signalling

OBJECTIVE

We sought to investigate the role of interleukin (IL)-20 in IBD and experimental colitis.

DESIGN

Experimental colitis was induced in mice deficient in components of the IL-20 and signal transducer and activator of transcription (STAT)2 signalling pathways. In vivo imaging, high-resolution mini-endoscopy and histology were used to assess intestinal inflammation. We further used RNA-sequencing (RNA-Seq), RNAScope and Gene Ontology analysis, western blot analysis and co-immunoprecipitation, confocal microscopy and intestinal epithelial cell (IEC)-derived three-dimensional organoids to investigate the underlying molecular mechanisms. Results were validated using samples from patients with IBD and non-IBD control subjects by a combination of RNA-Seq, organoids and immunostainings.

RESULTS

In IBD, IL20 levels were induced during remission and were significantly higher in antitumour necrosis factor responders versus non-responders. IL-20RA and IL-20RB were present on IECs from patients with IBD and IL-20-induced STAT3 and suppressed interferon (IFN)-STAT2 signalling in these cells. In IBD, experimental dextran sulfate sodium (DSS)-induced colitis and mucosal healing, IECs were the main producers of IL-20. Compared with wildtype controls, Il20-/-, Il20ra-/- and Il20rb-/- mice were more susceptible to experimental DSS-induced colitis. IL-20 deficiency was associated with increased IFN/STAT2 activity in mice and IFN/STAT2-induced necroptotic cell death in IEC-derived organoids could be markedly blocked by IL-20. Moreover, newly generated Stat2ΔIEC mice, lacking STAT2 in IECs, were less susceptible to experimental colitis compared with wildtype controls and the administration of IL-20 suppressed colitis activity in wildtype animals.

CONCLUSION

IL-20 controls colitis and mucosal healing by interfering with the IFN/STAT2 death signalling pathway in IECs. These results indicate new directions for suppressing gut inflammation by modulating IL-20-controlled STAT2 signals.

Long-term outcomes of cyclosporin induction and ustekinumab maintenance combination therapy in patients with steroid-refractory acute severe ulcerative colitis

Background

Effective management of patients with acute severe ulcerative colitis (ASUC) is a major challenge and there remains a paucity of available maintenance treatment options after efficacious cyclosporin induction therapy.

Objectives

We investigated the long-term effectiveness and safety of cyclosporin and ustekinumab combination therapy in patients with steroid refractory ASUC.

Design

Monocentric, prospective study.

Methods

We included patients with steroid refractory ASUC with multiple failed prior advanced therapies, who were treated with cyclosporin and ustekinumab combination therapy.

Results

Among the 11 included patients, 10 had prior failure to infliximab and 8 failed at least three previous biological therapies. The mean baseline Mayo and Lichtiger scores were 10.9 (9-12) and 13.3 (11-14), respectively. Ustekinumab was initiated 3.2 weeks (1-8) after initiation of cyclosporin treatment and combination therapy was continued for a mean of 11.5 (4-20) weeks. Clinical response was achieved in six patients at week 16 and clinical steroid-free clinical remission in five patients at week 48. Endoscopic remission was achieved in five patients at week 16 and together with histological remission in five patients at week 52. Intestinal ultrasound demonstrated mean bowel wall thickening in the sigmoid colon of 5.5 mm at baseline and 3.5 mm at week 52, respectively. Two patients had to undergo colectomy (mean 4.5 months, range 3-6) and three stopped ustekinumab therapy due to ineffectiveness. Overall, combination therapy was well tolerated.

Conclusion

Combination of cyclosporin and ustekinumab therapy allowed nearly half of ASUC patients to reach clinical and endoscopic remission after 52 weeks, warranting further studies.

Trial registration

Not applicable.

Healing of the epithelial barrier in the ileum is superior to endoscopic and histologic remission for predicting major adverse outcomes in ulcerative colitis

Background

Achieving endoscopic remission is a key therapeutic goal in patients with ulcerative colitis (UC) that is associated with favorable long-term disease outcomes. Here, we prospectively compared the predictive value of endoscopic and/or histologic remission against ileal barrier healing for predicting long-term disease behavior in a large cohort of UC patients in clinical remission.

Methods

At baseline, UC patients in clinical remission underwent ileocolonoscopy with assessment of ileal barrier function by confocal endomicroscopy. Endoscopic and histologic disease activity and ileal barrier healing were scored using validated scores. During subsequent follow-up (FU), patients were closely monitored for clinical disease activity and occurrence of major adverse outcomes (MAO) defined as the following: disease relapse; UC-related hospitalization; UC-related surgery; necessity for initiation or dose escalation of systemic steroids, immunosuppressants, small molecules or biological therapy.

Results

Of the 73 UC patients included, 67% experienced MAO during a mean FU of 25 months. The probability of MAO-free survival was significantly higher in UC patients with endoscopic and/or histologic remission compared to patients with endoscopically and/or histologically active disease. Ileal barrier healing on endomicroscopy was highly accurate for predicting the further course of UC and outcompeted endoscopic and histologic remission for predicting MAO-free survival.

Conclusion

Ileal barrier healing in clinically remittent UC patients can accurately predict future MAO development and is superior in its predictive capabilities than endoscopic and histologic remission. Ileal barrier healing therefore represents a novel and superior surrogate parameter for stratification of UC patients according to their risk for development of complicated disease behavior.

Clinical trial registration

https://classic.clinicaltrials.gov/ct2/show/NCT05157750, identifier NCT05157750.

A spotlight on intestinal permeability and inflammatory bowel diseases

INTRODUCTION

The intestinal barrier is a multi-faced structure lining the surface of the intestinal mucosa of the GI tract. To exert its main functions as a physical and immunological defense barrier, several components of the intestinal barrier act in a concerted and cooperative manner.

AREAS COVERED

Herein, we first introduce to the basic organization of the intestinal barrier and then summarize different methods to assess barrier function in and ex vivo. Finally, we provide an in-depth overview of the relevance of intestinal barrier dysfunction in inflammatory bowel diseases.

EXPERT OPINION

In parallel to a more fundamental understanding of the intestinal barrier as a key component for intestinal integrity is the notion that intestinal barrier defects are associated with a variety of diseases such as inflammatory bowel diseases. Recent research has fueled and perpetuated the concept that barrier defects are critical components of disease development, disease behavior, and potentially also an area of therapeutic intervention in IBD patients. Although being far away from standard, new technologies can be used to easily assess barrier healing in IBD and to derive clinical consequences from these findings such as more accurate forecasting of future disease behavior or the identification of novel therapeutic targets.

Current and Emerging Targeted Therapies for Ulcerative Colitis

Background

Ulcerative colitis is one of the main entities of inflammatory bowel diseases. The clinical course of this immune-mediated disorder is marked by unpredictable exacerbations and asymptomatic remission, causing lifelong morbidity. Optimized anti-inflammatory treatment is a prerequisite to not only restore the quality of life of the affected patients but also halt progressive bowel damage and reduce the risk for colitis-associated neoplasia. Advances in understanding the underlying immunopathogenesis of ulcerative colitis have led to the advent of targeted therapies that selectively inhibit crucial molecular structures or signaling pathways that perpetuate the inflammatory reaction.

Summary

We will delineate the mode of action and summarize efficacy and safety data of current and emerging targeted therapies in ulcerative colitis, which encompasses representatives of the drug classes of antibodies, small molecules, and oligonucleotides. These substances have already been approved for induction and maintenance treatment or are being tested in late-stage clinical trials in moderately-to-severely active ulcerative colitis patients. These advanced therapies have enabled us to define and achieve novel therapeutic outcomes, such as clinical and endoscopic remission, histological remission, mucosal healing, and recently, also barrier healing as an emerging outcome measure.

Key Messages

Established and emerging targeted therapies and monitoring modalities broaden our therapeutic armamentarium and have enabled us to define novel therapeutic outcomes that have the potential to modify the individual disease course of patients with ulcerative colitis.

Artificial Intelligence enabled histological prediction of remission or activity and clinical outcomes in ulcerative colitis

BACKGROUND

Microscopic inflammation has significant prognostic value in ulcerative colitis (UC); however, its assessment is complex with high interobserver variability. We aimed to develop and validate an artificial intelligence (AI) Computer-Aided Diagnosis System to evaluate UC biopsies and predict prognosis.

METHODS

535 digitalized biopsies (273 patients) were graded according to the PICaSSO Histologic Remission Index (PHRI), Robarts' (RHI), and Nancy Histological Index (NHI). A convolutional neural network classifier was trained to distinguish remission from activity on a subset of 118 biopsies, calibrated on 42 and tested on 375. The model was additionally tested to predict the corresponding endoscopic assessment and occurrence of flares at 12 months. The system output was compared with human assessment. Diagnostic performance was reported as sensitivity, specificity; prognostic prediction through Kaplan-Meier and hazard ratios of flares between active and remission groups. We externally validated the model in 154 biopsies (58 patients) with similar characteristics but more histologically active patients.

RESULTS

The system distinguished histological activity/remission with sensitivity and specificity of 89% and 85% (PHRI), 94% and 76% (RHI), and 89% and 79% (NHI). The model predicted the corresponding endoscopic remission/activity with 79% and 82% accuracy for UCEIS and PICaSSO, respectively. The hazard ratio for disease flare-up between histological activity/remission groups according to pathologist-assessed PHRI was 3.56, and 4.64 for AI-assessed PHRI. Both histology and outcome prediction were confirmed in the external validation cohort.

CONCLUSION

We developed and validated an AI model that distinguishes histological remission/activity in biopsies of UC and predicts flare-ups. This can expedite, standardize and enhance histological assessment in practice and trials.

Intestinal Barrier Healing Is Superior to Endoscopic and Histologic Remission for Predicting Major Adverse Outcomes in Inflammatory Bowel Disease: The Prospective ERIca Trial

BACKGROUND & AIMS

Endoscopic and histologic remission have emerged as key therapeutic goals in the management of inflammatory bowel diseases (IBD) that are associated with favorable long-term disease outcomes. Here, we prospectively compared the predictive value of barrier healing with endoscopic and histologic remission for predicting long-term disease behavior in a large cohort of patients with IBD in clinical remission.

METHODS

At baseline, patients with IBD in clinical remission underwent ileocolonoscopy with assessment of intestinal barrier function by confocal endomicroscopy. Endoscopic and histologic disease activity, as well as barrier healing, was prospectively assessed along established scores. During subsequent follow-up, patients were closely monitored for clinical disease activity and the occurrence of major adverse outcomes (MAOs): disease flares, IBD-related hospitalization or surgery, and initiation or dose escalation of systemic steroids, immunosuppressants, small molecules, or biological therapy.

RESULTS

The final analysis included 181 patients, 100 with Crohn's disease [CD] and 81 with ulcerative colitis (UC). During a mean follow-up of 35 (CD) and 25 (UC) months, 73% of patients with CD and 69% of patients with UC experienced at least 1 MAO. The probability of MAO-free survival was significantly higher in patients with IBD with endoscopic remission compared with endoscopically active disease. In addition, histologic remission predicted MAO-free survival in patients with UC but not CD. Barrier healing on endomicroscopy was superior to endoscopic and histologic remission for predicting MAO-free survival in both UC and CD.

CONCLUSIONS

Barrier healing is associated with decreased risk of disease progression in patients with clinically remittent IBD, with superior predictive performance compared with endoscopic and histologic remission. Analysis of barrier function might be considered as a future treatment target in clinical trials.

CLINICALTRIALS

gov number, NCT05157750.

Endocytoscopy for assessing histologic inflammation in ulcerative colitis: development and prospective validation of the ELECT (ErLangen Endocytoscopy in ColiTis) score (with videos)

BACKGROUND AND AIMS

Apart from endoscopic healing as an established treatment goal in patients with inflammatory bowel disease (IBD), histologic remission is an emerging endpoint that might even better predict disease outcome, especially in ulcerative colitis (UC). Within this study, we aimed to evaluate whether endocytoscopy (EC) as an in vivo contact microscopy technology can accurately assess histologic inflammation and predict the further course of disease in UC patients.

METHODS

Initially, a new and intuitive EC score reflecting the entire spectrum of microscopic disease activity in UC was consensually developed. Subsequently, this score was independently validated in 46 patients with UC who underwent close-meshed follow-up during which major adverse outcomes (MAOs; defined as disease flare, IBD-related hospitalization, IBD-related surgery, necessity for initiation or escalation therapy) were recorded. Results of EC grading of inflammatory activity were compared against 2 validated histologic scores in UC. Diagnostic performance of endoscopic remission under white-light endoscopy (Mayo Endoscopic Score and Ulcerative Colitis Endoscopic Index of Severity), EC, and histology were compared for the prediction of MAOs.

RESULTS

Endocytoscopic assessment of inflammatory activity in UC based on the newly developed ErLangen Endocytoscopy in ColiTis score showed strong correlation with histopathologic scoring (Robarts Histopathology Index, r = .70; Nancy Histologic Index, r = .73) and was superior to white-light endoscopy for grading of microscopic disease activity, with a sensitivity of 88%, specificity of 95.2%, and area under the curve of .916. Furthermore, EC exhibited a high interobserver agreement for in vivo grading of microscopic inflammation and was comparably accurate as histopathology for forecasting the occurrence of MAOs in UC.

CONCLUSIONS

Endocytoscopic grading of inflammatory activity along a newly developed scoring system enabled real-time histology in UC patients and better predicted clinical outcome in UC patients than endoscopic remission.

Autologous regulatory T-cell transfer in refractory ulcerative colitis with concomitant primary sclerosing cholangitis

OBJECTIVE

Ulcerative colitis (UC) is a chronic, debilitating immune-mediated disease driven by disturbed mucosal homeostasis, with an excess of intestinal effector T cells and an insufficient expansion of mucosal regulatory T cells (Tregs). We here report on the successful adoptive transfer of autologous, ex vivo expanded Tregs in a patient with refractory UC and associated primary sclerosing cholangitis (PSC), for which effective therapy is currently not available.

DESIGN

The patient received a single infusion of 1×10⁶ autologous, ex vivo expanded, polyclonal Tregs per kilogram of body weight, and the clinical, biochemical, endoscopic and histological responses were assessed 4 and 12 weeks after adoptive Treg transfer.

RESULTS

The patient showed clinical, biochemical, endoscopic and histological signs of response until week 12 after adoptive Treg transfer, which was associated with an enrichment of intestinal CD3⁺/FoxP3⁺ and CD3⁺/IL-10⁺ T cells and increased mucosal transforming growth factor beta and amphiregulin levels. Moreover, there was marked improvement of PSC with reduction of liver enzymes. This pronounced effect lasted for 4 weeks before values started to increase again.

CONCLUSION

These findings suggest that adoptive Treg therapy might be effective in refractory UC and might open new avenues for clinical trials in PSC.

TRIAL REGISTRATION NUMBER

NCT04691232.

Motorized spiral enteroscopy: results of an international multicenter prospective observational clinical study in patients with normal and altered gastrointestinal anatomy

BACKGROUND : Motorized spiral enteroscopy (MSE) has been shown to be safe and effective for deep enteroscopy in studies performed at expert centers with limited numbers of patients without previous abdominal surgery. This study aimed to investigate the safety, efficacy, and learning curve associated with MSE in a real-life scenario, with the inclusion of patients after abdominal surgery and with altered anatomy. METHODS : Patients with indications for deep enteroscopy were enrolled in a prospective observational multicenter study. The primary objective was the serious adverse event (SAE) rate; secondary objectives were the diagnostic and therapeutic yield, procedural success, time, and insertion depth. Data analysis was subdivided into training and core (post-training) study phases at centers with different levels of MSE experience. RESULTS : 298 patients (120 women; median age 68, range 19-92) were enrolled. In the post-training phase, 21.5 % (n = 54) had previous abdominal surgery, 10.0 % (n = 25) had surgically altered anatomy. Overall, SAEs occurred in 2.3 % (7/298; 95 %CI 0.9 %-4.8 %). The SAE rate was 2.0 % (5/251) in the core group and 4.3 % (2/47) in the training group, and was not increased after abdominal surgery (1.9 %). Total enteroscopy was achieved in half of the patients (n = 42) undergoing planned total enteroscopy. In 295/337 procedures (87.5 %), the anatomical region of interest could be reached. CONCLUSIONS : This prospective multicenter study showed that MSE was feasible and safe in a large cohort of patients in a real-life setting, after a short learning curve. MSE was shown to be feasible in postsurgical patients, including those with altered anatomy, without an increase in the SAE rate.

Constrained multiple instance learning for ulcerative colitis prediction using histological images

BACKGROUND AND OBJECTIVE

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) affecting the colon and the rectum characterized by a remitting-relapsing course. To detect mucosal inflammation associated with UC, histology is considered the most stringent criteria. In turn, histologic remission (HR) correlates with improved clinical outcomes and has been recently recognized as a desirable treatment target. The leading biomarker for assessing histologic remission is the presence or absence of neutrophils. Therefore, the finding of this cell in specific colon structures indicates that the patient has UC activity. However, no previous studies based on deep learning have been developed to identify UC based on neutrophils detection using whole-slide images (WSI).

METHODS

The methodological core of this work is a novel multiple instance learning (MIL) framework with location constraints able to determine the presence of UC activity using WSI. In particular, we put forward an effective way to introduce constraints about positive instances to effectively explore additional weakly supervised information that is easy to obtain and enjoy a significant boost to the learning process. In addition, we propose a new weighted embedding to enlarge the relevance of the positive instances.

RESULTS

Extensive experiments on a multi-center dataset of colon and rectum WSIs, PICASSO-MIL, demonstrate that using the location information we can improve considerably the results at WSI-level. In comparison with prior MIL settings, our method allows for 10% improvements in bag-level accuracy.

CONCLUSION

Our model, which introduces a new form of constraints, surpass the results achieved from current state-of-the-art methods that focus on the MIL paradigm. Our method can be applied to other histological concerns where the morphological features determining a positive WSI are tiny and similar to others in the image.

PICaSSO Histologic Remission Index (PHRI) in ulcerative colitis: development of a novel simplified histological score for monitoring mucosal healing and predicting clinical outcomes and its applicability in an artificial intelligence system

Histological remission is evolving as an important treatment target in UC. We aimed to develop a simple histological index, aligned to endoscopy, correlated with clinical outcomes, and suited to apply to an artificial intelligence (AI) system to evaluate inflammatory activity.

METHODS

Using a set of 614 biopsies from 307 patients with UC enrolled into a prospective multicentre study, we developed the Paddington International virtual ChromoendoScopy ScOre (PICaSSO) Histologic Remission Index (PHRI). Agreement with multiple other histological indices and validation for inter-reader reproducibility were assessed. Finally, to implement PHRI into a computer-aided diagnosis system, we trained and tested a novel deep learning strategy based on a CNN architecture to detect neutrophils, calculate PHRI and identify active from quiescent UC using a subset of 138 biopsies.

RESULTS

PHRI is strongly correlated with endoscopic scores (Mayo Endoscopic Score and UC Endoscopic Index of Severity and PICaSSO) and with clinical outcomes (hospitalisation, colectomy and initiation or changes in medical therapy due to UC flare-up). A PHRI score of 1 could accurately stratify patients' risk of adverse outcomes (hospitalisation, colectomy and treatment optimisation due to flare-up) within 12 months. Our inter-reader agreement was high (intraclass correlation 0.84). Our preliminary AI algorithm differentiated active from quiescent UC with 78% sensitivity, 91.7% specificity and 86% accuracy.

CONCLUSIONS

PHRI is a simple histological index in UC, and it exhibits the highest correlation with endoscopic activity and clinical outcomes. A PHRI-based AI system was accurate in predicting histological remission.

Endoscopic remission assessed with PICaSSO virtual electronic chromendoscopy accurately predicts clinical outcomes in ulcerative colitis

BACKGROUND AND AIMS

A composite endoscopic-histologic remission is increasingly explored as an important endpoint in ulcerative colitis (UC). We investigated combined endoscopic-histologic remission for predicting clinical outcomes at 12 months compared with endoscopic remission alone using the high definition virtual chromoendoscopy (VCE) Paddington International virtual ChromoendoScopy ScOre (PICaSSO) and histology scores.

METHODS

Ulcerative colitis patients, prospectively enrolled from 11 international centres, underwent VCE with targeted biopsies and followed up for 12 months. Endoscopic activity was assessed by Mayo Endoscopic Score (MES), Ulcerative Colitis Endoscopic Index Severity (UCEIS) followed by VCE-PICaSSO. Robarts Histopathological Index|Robarts Histological index≤3 without neutrophils in mucosa, and Nancy Histological index (NHI)≤ 1 were used to define histologic remission. Combined endoscopic-histologic remission was compared with endoscopic remission alone by Cox proportional hazards model and by two- and three-proportion analysis using pre-specified clinical outcomes.

RESULTS

307 patients were recruited and 302 analysed. There was no difference in survival without specified clinical outcomes between PICaSSO defined endoscopic remission alone and endoscopic plus histologic remission in the rectum (HR 0.42, 95%CI 0.16-1.11 and HR 1.03, 95%CI 0.42-2.52 for Robarts Histological index and NHI respectively) at 12 months. There was however a significant survival advantage without specified clinical outcome events for UCEIS combined with histology compared with UCEIS alone (HR 0.30, 95%CI 0.12-0.75, p = 0.02) at 12 months (but not combined with NHI). For MES there was no advantage for predicting specified clinical outcomes at 12 months for endoscopy alone versus endoscopy plus histology, but there were differences in two and three proportion analysis at 6 months.

CONCLUSION

Endoscopic remission by VCE-PICaSSO alone was similar to combined endoscopic and histologic remission for predicting specified clinical outcomes at 12 months. Larger studies with specific therapeutic interventions are required to further confirm the findings.

Real-time colorectal polyp detection using a novel computer-aided detection system (CADe): a feasibility study

BACKGROUND AND AIMS

Colonoscopy aims to early detect and remove precancerous colorectal polyps, thereby preventing development of colorectal cancer (CRC). Recently, computer-aided detection (CADe) systems have been developed to assist endoscopists in polyp detection during colonoscopy. The aim of this study was to investigate feasibility and safety of a novel CADe system during real-time colonoscopy in three European tertiary referral centers.

METHODS

Ninety patients undergoing colonoscopy assisted by a real-time CADe system (DISCOVERY; Pentax Medical, Tokyo, Japan) were prospectively included. The CADe system was turned on only at withdrawal, and its output was displayed on secondary monitor. To study feasibility, inspection time, polyp detection rate (PDR), adenoma detection rate (ADR), sessile serrated lesion (SSL) detection rate (SDR), and the number of false positives were recorded. To study safety, (severe) adverse events ((S)AEs) were collected. Additionally, user friendliness was rated from 1 (worst) to 10 (best) by endoscopists.

RESULTS

Mean inspection time was 10.8 ± 4.3 min, while PDR was 55.6%, ADR 28.9%, and SDR 11.1%. The CADe system users estimated that < 20 false positives occurred in 81 colonoscopy procedures (90%). No (S)AEs related to the CADe system were observed during the 30-day follow-up period. User friendliness was rated as good, with a median score of 8/10.

CONCLUSION

Colonoscopy with this novel CADe system in a real-time setting was feasible and safe. Although PDR and SDR were high compared to previous studies with other CADe systems, future randomized controlled trials are needed to confirm these detection rates. The high SDR is of particular interest since interval CRC has been suggested to develop frequently through the serrated neoplasia pathway.

CLINICAL TRIAL REGISTRATION

The study was registered in the Dutch Trial Register (reference number: NL8788).

Current Endoscopic Resection Techniques for Gastrointestinal Lesions: Endoscopic Mucosal Resection, Submucosal Dissection, and Full-Thickness Resection

Background

Endoscopic resection of dysplastic lesions in early stages of cancer reduces mortality rates and is recommended by many national guidelines throughout the world. Snare polypectomy and endoscopic mucosal resection (EMR) are established techniques of polyp removal. The advantages of these methods are their relatively short procedure times and acceptable complication rates. The latter include delayed bleeding in 0.9% and a perforation risk of 0.4-1.3%, depending on the size and location of the resected lesion. EMR is a recent modification of endoscopic resection. A limited number of studies suggest that larger lesions can be removed en bloc with low complication rates and short procedure times. Novel techniques such as endoscopic submucosal dissection (ESD) are used to enhance en bloc resection rates for larger, flat, or sessile lesions. Endoscopic full-thickness resection (EFTR) is employed for non-lifting lesions or those not easily amenable to resection. Procedures such as ESD or EFTR are emerging standards for lesions inaccessible to EMR techniques.

Summary

Endoscopic treatment is now regarded as first-line therapy for benign lesions.

Key Message

Endoscopic resection of dysplastic lesions or early stages of cancer is recommended. A plethora of different techniques can be used dependent on the lesions.

Validation of the 'Inflammatory Bowel Disease-Distribution, Chronicity, Activity [IBD-DCA] Score' for Ulcerative Colitis and Crohn´s Disease

BACKGROUND AND AIMS

Histological scoring plays a key role in the assessment of disease activity in ulcerative colitis [UC] and is also important in Crohn´s disease [CD]. Currently, there is no common scoring available for UC and CD. We aimed to validate the Inflammatory Bowel Disease [IBD]-Distribution [D], Chronicity [C], Activity [A] score [IBD-DCA score] for histological disease activity assessment in IBD.

METHODS

Inter- and intra-rater reliability were assessed by 16 observers on biopsy specimens from 59 patients with UC and 25 patients with CD. Construct validity and responsiveness to treatment were retrospectively evaluated in a second cohort of 30 patients.

RESULTS

Inter-rater reliability was moderate to good for the UC cohort (intraclass correlation coefficients [ICCs] = 0.645, 0.623, 0.767 for D, C, and A, respectively) and at best moderate for the CD cohort [ICC = 0.690, 0.303, 0.733 for D, C, and A, respectively]. Intra-rater agreement ranged from good to excellent in both cohorts. Correlation with the Nancy Histological Index [NHI] was moderate and strong with the Simplified Geboes Score [SGS] and a Visual Analogue Scale [VAS], respectively. Large effect sizes were obtained for all three parameters. External responsiveness analysis revealed correlated changes between IBD-DCA score and NHI, SGS and VAS.

CONCLUSIONS

The IBD-DCA score is a simple histological activity score for UC and CD, agreed and validated by a large group of IBD specialists. It provides reliable information on treatment response. Therefore, it has potential value for use in routine diagnostics as well as clinical studies.

Targeting of the Tec Kinase ITK Drives Resolution of T Cell-Mediated Colitis and Emerges as Potential Therapeutic Option in Ulcerative Colitis

BACKGROUND & AIMS

The molecular checkpoints driving T cell activation and cytokine responses in ulcerative colitis (UC) are incompletely understood. Here, we studied the Tec kinase ITK in UC.

METHODS

We analyzed patients with inflammatory bowel disease (n = 223) and evaluated ITK activity as well as the functional effects of cyclosporine-A (CsA). In addition, 3 independent murine colitis models were used to investigate the functional role of ITK. Finally, the activity of ITK was blocked via pharmacological inhibitors and genetically engineered mice. Readout parameters were mini-endoscopy, histopathology, mucosal T cell apoptosis, and cytokine production.

RESULTS

We found an expansion of pITK-expressing mucosal CD4+ T cells in UC rather than Crohn's disease that correlated with disease severity. CsA suppressed activation of ITK in cultured CD4+ T cells and calcineurin-containing microclusters adjacent to the T cell receptor signaling complex. Functionally, the capacity of CsA to suppress activity of experimental colitis was critically dependent on ITK. Genetic inactivation of Itk via gene targeting or induction of allele-sensitive Itk mutants prevented experimental colitis in 3 colitis models, and treatment with pharmacological ITK blockers suppressed established colitis. In addition, ITK controlled apoptosis and activation of mucosal Th2 and Th17 lymphocytes via NFATc2 signaling pathways.

CONCLUSIONS

ITK activation was detected in UC and could be down-regulated in cultured T cells by CsA administration. Selective targeting of ITK emerges as an attractive approach for treatment of chronic intestinal inflammation and potentially UC by driving resolution of mucosal inflammation.

Mucosal Biofilms Are an Endoscopic Feature of Irritable Bowel Syndrome and Ulcerative Colitis

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) and inflammatory bowel diseases result in a substantial reduction in quality of life and a considerable socioeconomic impact. In IBS, diagnosis and treatment options are limited, but evidence for involvement of the gut microbiome in disease pathophysiology is emerging. Here we analyzed the prevalence of endoscopically visible mucosal biofilms in gastrointestinal disease and associated changes in microbiome composition and metabolism.

METHODS

The presence of mucosal biofilms was assessed in 1426 patients at 2 European university-based endoscopy centers. One-hundred and seventeen patients were selected for in-depth molecular and microscopic analysis using 16S ribosomal RNA gene amplicon-sequencing of colonic biopsies and fecal samples, confocal microscopy with deep learning-based image analysis, scanning electron microscopy, metabolomics, and in vitro biofilm formation assays.

RESULTS

Biofilms were present in 57% of patients with IBS and 34% of patients with ulcerative colitis compared with 6% of controls (P < .001). These yellow-green adherent layers of the ileum and right-sided colon were microscopically confirmed to be dense bacterial biofilms. 16S-sequencing links the presence of biofilms to a dysbiotic gut microbiome, including overgrowth of Escherichia coli and Ruminococcus gnavus. R. gnavus isolates cultivated from patient biofilms also formed biofilms in vitro. Metabolomic analysis found an accumulation of bile acids within biofilms that correlated with fecal bile acid excretion, linking this phenotype with a mechanism of diarrhea.

CONCLUSIONS

The presence of mucosal biofilms is an endoscopic feature in a subgroup of IBS and ulcerative colitis with disrupted bile acid metabolism and bacterial dysbiosis. They provide novel insight into the pathophysiology of IBS and ulcerative colitis, illustrating that biofilm can be seen as a tipping point in the development of dysbiosis and disease.

The Ominous Ouzo Party - A Case Series of Four Patients with Accidental Alkali Ingestion

Background

Ingestion of alkaline fluids is a common problem, which can lead to perforations, strictures and malignancy. We present a rare case series of several patients who accidentally ingested the same alkaline substance in different doses.

Methods

We investigated four patients with accidental ingestion of dishwashing liquid. All patients underwent gastroscopy within 24h after inpatient admission. Gastroesophageal lesions were classified according to the Zargar classification for corrosive ingestions.

Results

Esophagogastric lesions were predominantly found at the distal esophagus and the small curvature of the stomach. The severity of these lesions ranged from mild erosions (Zargar 2A) to marked necrosis (Zargar 3A). Our data suggest that the degree of these lesions correlated with the amount of ingested toxin and duration of the inpatient stay. However, a low symptom severity or inconspicuous otolaryngologic examination did not exclude severe gastroesophageal lesions.

Conclusion

Our data suggest that the severity of gastroesophageal lesions correlates with the amount of ingested alkaline substance. Symptom burden and an otolaryngologic examination are not sufficiently predictive for the severity of gastroesophageal lesions. The composition and quantity of the swallowed liquid should be determined.

Innovative Diagnostic Endoscopy in Inflammatory Bowel Diseases: From High-Definition to Molecular Endoscopy

High-definition endoscopy is one essential step in the initial diagnosis of inflammatory bowel disease (IBD) characterizing the extent and severity of inflammation, as well as discriminating ulcerative colitis (UC) from Crohn's disease (CD). Following general recommendations and national guidelines, individual risk stratification should define the appropriate surveillance strategy, biopsy protocol and frequency of endoscopies. Beside high-definition videoendoscopy the application of dyes applied via a spraying catheter is of additional diagnostic value with a higher detection rate of intraepithelial neoplasia (IEN). Virtual chromoendoscopy techniques (NBI, FICE, I-scan, BLI) should not be recommended as a single surveillance strategy in IBD, although newer data suggest a higher comparability to dye-based chromoendoscopy than previously assumed. First results of oral methylene blue formulation are promising for improving the acceptance rate of classical chromoendoscopy. Confocal laser endomicroscopy (CLE) is still an experimental but highly innovative endoscopic procedure with the potential to contribute to the detection of dysplastic lesions. Molecular endoscopy in IBD has taken application of CLE to a higher level and allows topical application of labeled probes, mainly antibodies, against specific target structures expressed in the tissue to predict response or failure to biological therapies. First pre-clinical and in vivo data from label-free multiphoton microscopy (MPM) are now available to characterize mucosal and submucosal inflammation on endoscopy in more detail. These new techniques now have opened the door to individualized and highly specific molecular imaging in IBD in the future and pave the path to personalized medicine approaches. The quality of evidence was stated according to the Oxford Center of evidence-based medicine (March 2009). For this review a Medline search up to January 2021 was performed using the words “inflammatory bowel disease,” “ulcerative colitis,” “crohn's disease,” “chromoendoscopy,” “high-definition endoscopy,” “confocal laser endomicroscopy,” “confocal laser microscopy,” “molecular imaging,” “multiphoton microscopy.”

Is histological healing a feasible endpoint in ulcerative colitis?

INTRODUCTION

Currently, treatment goals in ulcerative colitis aim to achieve clinical remission and endoscopic mucosal healing. Emerging evidence suggests that histologic assessment of inflammation is a sensitive marker that can outcompete mucosal healing in predicting the clinical course of disease in patients with ulcerative colitis. Based on this, histologic healing is frequently included as a secondary endpoint in pharmacological trials.

AREAS COVERED

We introduce currently used clinical and endoscopic treatment goals, summarize commonly used histologic scoring systems and then provide an overview on the relevance of histologic healing on the outcome in patients with ulcerative colitis. Finally, we review the efficacy of existing UC therapies for inducing histologic remission.

EXPERT OPINION

Histologic healing is achievable in a substantial portion of UC patients. Further, histologic healing is, as consolidated by several meta-analyses, associated with better disease outcome compared to clinical remission and/or endoscopic healing. However, before becoming a widely acceptable treatment endpoint, consensus definitions for histologic healing and the technical aspects as well as for the timing for obtaining biopsies are needed. And finally, we need more evidence to show that resolution of microscopic inflammation as a means of therapy change or dose escalation is indeed a superior endpoint.

Multicenter cohort study of patients with buried bumper syndrome treated endoscopically with a novel, dedicated device

BACKGROUND AND AIMS

Buried bumper syndrome (BBS) is a rare adverse event of percutaneous endoscopic gastrostomy (PEG) placement in which the internal bumper migrates through the stomal tract to become embedded within the gastric wall. Excessive tension between the internal and external bumpers, causing ischemic necrosis of the gastric wall, is believed to be the main etiologic factor. Several techniques for endoscopic management of BBS have been described using off-label devices. The Flamingo set is a novel, sphincterotome-like device specifically designed for BBS management. We aimed to evaluate the effectiveness of the Flamingo device in a large, homogeneous cohort of patients with BBS.

METHODS

A guidewire was inserted through the external access of the PEG tube into the gastric lumen. The Flamingo device was then introduced into the stomach over the guidewire. This dedicated tool can be flexed by 180 degrees, exposing a sphincterotome-like cutting wire, which is used to incise the overgrown tissue until the PEG bumper is exposed. A retrospective, international, multicenter cohort study was conducted on 54 patients between December 2016 and February 2019.

RESULTS

The buried bumper was successfully removed in 53 of 55 procedures (96.4%). The median time for the endoscopic removal of the buried bumper was 22 minutes (range, 5-60). Periprocedural endoscopic adverse events occurred in 7 procedures (12.7%) and were successfully managed endoscopically. A median follow-up of 150 days (range, 33-593) was performed in 29 patients (52.7%), during which no significant adverse events occurred.

CONCLUSIONS

Through our experience, we found this dedicated novel device to be safe, quick, and effective for minimally invasive, endoscopic management of BBS.

An International Multicenter Real-Life Prospective Study of Electronic Chromoendoscopy Score PICaSSO in Ulcerative Colitis

BACKGROUND & AIMS

Endoscopic and histologic remission are important goals in the treatment of ulcerative colitis (UC). We investigated the correlation of the recently developed Paddington International Virtual ChromoendoScopy ScOre (PICaSSO) and other established endoscopic scores against multiple histological indices and prospectively assessed outcomes.

METHODS

In this prospective multicenter international study, inflammatory activity was assessed with high-definition and virtual chromoendoscopy in the rectum and sigmoid using the Mayo Endoscopic Score (MES), UC Endoscopic Index of Severity (UCEIS), and PICaSSO. Targeted biopsies were taken for assessment using Robarts Histological Index (RHI), Nancy Histological index (NHI), ECAP (Extent, Chronicity, Activity, Plus score), Geboes, and Villanacci. Follow-up data were obtained at 6 and 12 months after colonoscopy.

RESULTS

A total of 307 patients were recruited. There was strong correlation between PICaSSO and histology scores, significantly superior to correlation coefficients of MES and UCEIS with histology scores. A PICaSSO score of ≤3 detected histologic remission by RHI (≤3 + absence of neutrophils) with area under the receiver operating characteristic curve (AUROC) 0.90 (95% confidence interval [CI] 0.86-0.94) and NHI (≤1) AUROC 0.82 (95% CI 0.77-0.87). The interobserver agreement for PICaSSO was 0.88 (95% CI 0.83-0.92). At 6- and 12-months follow-up, PICaSSO score ≤3 predicted better outcomes than PICaSSO >3 (hazard ratio [HR] 0.19 [0.11-0.33] and 0.22 [0.13-0.34], respectively),} as well as PICaSSO 4-8 (HR 0.25 [0.12-0.53] and 0.22 (0.12-0.39), respectively) and similar to histologic remission.

CONCLUSION

In this first real-life multicenter study, the PICaSSO score correlated strongly with multiple histological indices. Furthermore, PICaSSO score predicted specified clinical outcomes at 6 and 12 months, similar to histology. Thus, PICaSSO can be a useful endoscopic tool in the therapeutic management of UC.

FcRn is a CD32a coreceptor that determines susceptibility to IgG immune complex-driven autoimmunity

IgG immune complexes (ICs) promote autoimmunity through binding fragment crystallizable (Fc) γ-receptors (FcγRs). Of these, the highly prevalent FcγRIIa (CD32a) histidine (H)-131 variant (CD32a^H) is strongly linked to human autoimmune diseases through unclear mechanisms. We show that, relative to the CD32a arginine (R)-131 (CD32a^R) variant, CD32a^H more avidly bound human (h) IgG1 IC and formed a ternary complex with the neonatal Fc receptor (FcRn) under acidic conditions. In primary human and mouse cells, both CD32a variants required FcRn to induce innate and adaptive immune responses to hIgG1 ICs, which were augmented in the setting of CD32a^H. Conversely, FcRn induced responses to IgG IC independently of classical FcγR, but optimal responses required FcRn and FcγR. Finally, FcRn blockade decreased inflammation in a rheumatoid arthritis model without reducing circulating autoantibody levels, providing support for FcRn’s direct role in IgG IC-associated inflammation. Thus, CD32a and FcRn coregulate IgG IC-mediated immunity in a manner favoring the CD32a^H variant, providing a novel mechanism for its disease association.

Food Intolerance of Unknown Origin: Caused by Mucosal Inflammation? A Pilot Study

INTRODUCTION

The prevalence of patients with food intolerance (FI) has increased significantly. Immunoglobulin (Ig)E-mediated food allergies (FAs) are detected by determining IgE antibodies and skin prick test. Carbohydrate malabsorptions are clarified with breath tests. However, these diagnostic measures cannot capture all intolerances and have limitations in case of gut-mediated FI. The aims of this pilot study were to evaluate different methods to determine intestinal mucosal IgE in patients with FA and to characterize the intestinal mucosa in patients with FI of unknown origin (FH).

METHODS

Patients with FA and FH were compared with healthy controls. To determine the IgE antibodies and the cytokines tumor necrosis factor (TNF)-α and interferon (IFN)-γ of the intestinal mucosal, a lavage was performed as part of an ileocolonoscopy and samples were taken using the cytobrush and biopsy forceps. In a subgroup, mucosal samples were also taken from the duodenum.

RESULTS

Data in homogenates of intestinal mucosal samples yielded the highest sensitivity for IgE antibody titers compared with lavage and cytobrush. Patients with FA presented increased intestinal TNF-α and low IFN-γ values. This was in contrast to FH patients, who showed low intestinal IgE antibodies and TNF-α levels, but increased IFN-γ values.

DISCUSSION

The determination of IgE antibodies to diagnose intestinal IgE-mediated FA is most reliable in intestinal mucosal samples. Increased TNF-α and low IFN-γ levels in patients with FA characterize an allergic reaction. Decreased TNF-α and increased IFN-γ levels in patients with FH indicate an inflammation-related intolerance reaction (see Visual Abstract, Supplementary Digital Content 1, http://links.lww.com/CTG/A520).

Endoscopic recanalization of complete esophageal obstruction

BACKGROUND AND AIMS

Complete esophageal obstruction (CEO) is a rare complication after radiochemotherapy that dramatically impairs quality of life. Within this study, we assessed the outcome of two different endoscopic techniques for lumen restoration in patients with CEO.

METHODS

17 patients were included. Esophageal recanalization was performed in an antegrade approach (Group A) or through combined antegrade and retrograde recanalization and dilatation (CARD, Group B). Technical success, complications, and dysphagia development during follow-up (FU) were compared between the groups.

RESULTS

In Group A (n = 6), esophageal recanalization was performed by a single endoscopist with a median duration of 47 min. In two patients, antegrade recanalization led to formation of a false lumen (i.e., submucosal tunneling) followed by mediastinitis. In Group B, 21 CARD procedures were performed in 11 patients with a technical success rate of 100%. Procedure time was longer compared to Group A; however, no intra- or postprocedural complications were observed in Group B.

CONCLUSIONS

In our experience and cohort, CARD was a successful procedure for recanalization of CEO, which exhibits a more favorable safety profile over antegrade recanalization. Further randomized studies to evaluate the treatment of CEO with CARD are needed.

Long-term effectiveness, safety and immunogenicity of the biosimilar SB2 in inflammatory bowel disease patients after switching from originator infliximab

BACKGROUND

Long-term data on inflammatory bowel disease (IBD) patients switched from originator to biosimilar infliximab SB2 are lacking. The aim of the conducted study was to investigate the effectiveness, immunogenicity and safety of a large prospectively followed-up IBD patient cohort that was entirely switched from originator infliximab to biosimilar SB2 treatment.

METHODS

This was a prospective, single-center, longitudinal, observational study describing clinical outcomes in IBD patients, over an 80-week period following switch from originator infliximab to SB2. Primary outcome measures were change of disease activity [Harvey-Bradshaw Index for Crohn's disease (CD), partial Mayo Score for ulcerative colitis (UC)], C-reactive protein (CRP), infliximab trough levels (TLs), anti-drug antibodies (ADAs) and adverse events.

RESULTS

One hundred and forty-four IBD patients (94 CD, 50 UC), with median duration of 30.5 months' (range 2-110) treatment with originator infliximab were evaluated. Mean change of disease activity compared with baseline was -0.9 (SD 2.6), -0.4 (2.2) and -0.4 (2.0) in CD; 0.1 (1.1), 0.1 (1.1) and 0.1 (1.3) in UC patients at weeks 24, 48 and 72. Median infliximab TLs were 6.2 µg/ml (interquartile range 2.3-12.2), 5.0 µg/ml (2.7-10.0), 6.6 µg/ml (3.5-12.4) and 5.1 µg/ml (2.7-10.9) at baseline and weeks 24, 48 and 72. Median CRP levels were within normal ranges throughout the study. After the switch, 9.8% of the patients developed new ADAs. Persistence on SB2 was 90% (95% confidence interval 0.85-0.95), 79% (0.72-0.86), 72% (0.64-0.80) at weeks 26, 52 and 78. Serious adverse events occurred in 11 patients.

CONCLUSION

Over the individual patient follow-up of 80 weeks, switch to biosimilar SB2 from originator infliximab does not result in increased disease activity or changed immunogenicity patterns. The switch to SB2 was well tolerated.

Successful cyclosporin and ustekinumab combination therapy in a patient with severe steroid-refractory ulcerative colitis

The therapeutic management of patients with severe steroid-refractory ulcerative colitis still represents a critical clinical challenge. In this setting, cyclosporin is an effective and rapidly acting induction treatment that is applied in combination with maintenance therapeutic agents like thiopurines or vedolizumab. Here, we present the case of a 33-year-old ulcerative colitis patient with severe steroid-refractory ulcerative colitis who refused surgical intervention and previously demonstrated no long-term benefit to anti-TNF antibody, vedolizumab, cyclosporin, thiopurines or tofacitinib treatment. Intravenous cyclosporin therapy was re-initiated in the patient and, after signs of clinical response, therapy with ustekinumab was additionally applied. After 11 weeks of well tolerated cyclosporin and ustekinumab combination therapy, cyclosporin was discontinued upon clinical and endoscopic remission. Subsequently, ustekinumab treatment has been effective in maintaining remission during the follow-up period of 195 days.

The JAK1/3 inhibitor tofacitinib suppresses T cell homing and activation in chronic intestinal inflammation

BACKGROUND & AIMS

The molecular mechanism of action of the Janus kinase (JAK) inhibitor tofacitinib is poorly understood.

METHODS

Here, we analysed the inhibitory effect of tofacitinib on mucosal and blood T cells from patients with ulcerative colitis (UC). Furthermore tofacitinib treatment was analysed in experimental colitis models and wound healing. Additionally, tofacitinib effects were analysed in bioassays.

RESULTS

Tofacitinib significantly reduced T cell derived inflammatory cytokine production (Th2, Th9, Th17) in patients with active UC. Additionally, impaired expression of the homing receptors alpha4/beta1 and alpha4/beta7 as well as reduced gut homing capacity of T cells in a humanized mouse model of colitis were observed. Tofacitinib suppressed acute and chronic oxazolone colitis compared to untreated wild-type mice associated with downregulation of cytokines produced by Th2, Th9 and Th17 cells. Functionally, tofacitinib induced apoptosis of intestinal epithelial cells and prevented mucosal wound healing in vivo at higher concentration. Thus, our findings suggest that tofacitinib is quite effective in protecting from colitis by inhibition of a bundle of T cell derived cytokines like IL-5, IL-6, IL-9, IL-13 and IL-17A.

CONCLUSION

Application of tofacitinib emerges as an attractive concept for treatment of chronic intestinal inflammation at lower concentrations, whereas higher concentrations require attention due to prolonged wound healing.

Technical success, resection status, and procedural complication rate of colonoscopic full-wall resection: a pooled analysis from 7 hospitals of different care levels

Introduction

Endoscopic full-thickness resection (eFTR) using the full-thickness resection device (FTRD®) is a novel minimally invasive procedure that allows the resection of various lesions in the gastrointestinal tract including the colorectum. Real-world data outside of published studies are limited. The aim of this study was a detailed analysis of the outcomes of colonoscopic eFTR in different hospitals from different care levels in correlation with the number of endoscopists performing eFTR.

Material and methods

In this case series, the data of all patients who underwent eFTR between November 2014 and June 2019 (performed by a total of 22 endoscopists) in 7 hospitals were analyzed retrospectively regarding rates of technical success, R0 resection, and procedure-related complications.

Results

Colonoscopic eFTR was performed in 229 patients (64.6% men; average age 69.3 ± 10.3 years) mainly on the basis of the following indication: 69.9% difficult adenomas, 21.0% gastrointestinal adenocarcinomas, and 7.9% subepithelial tumors. The average size of the lesions was 16.3 mm. Technical success rate of eFTR was achieved in 83.8% (binominal confidence interval 78.4–88.4%). Overall, histologically complete resection (R0) was achieved in 77.2% (CI 69.8–83.6%) while histologically proven full-wall excidate was confirmed in 90.0% (CI 85.1–93.7%). Of the resectates obtained (n = 210), 190 were resected en bloc (90.5%). We did not observe a clear improvement of technical success and R0 resection rate over time by the performing endoscopists. Altogether, procedure-related complications were observed in 17.5% (mostly moderate) including 2 cases of acute gangrenous appendicitis requiring operation.

Discussion

In this pooled analysis, eFTR represents a feasible, effective, and safe minimally invasive endoscopic technique.

Electronic supplementary material

The online version of this article (10.1007/s00464-020-07772-5) contains supplementary material, which is available to authorized users.

IFN-γ drives inflammatory bowel disease pathogenesis through VE-cadherin-directed vascular barrier disruption

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with rising incidence. Diseased tissues are heavily vascularized. Surprisingly, the pathogenic impact of the vasculature in IBD and the underlying regulatory mechanisms remain largely unknown. IFN-γ is a major cytokine in IBD pathogenesis, but in the context of the disease, it is almost exclusively its immune-modulatory and epithelial cell-directed functions that have been considered. Recent studies by our group demonstrated that IFN-γ also exerts potent effects on blood vessels. Based on these considerations, we analyzed the vessel-directed pathogenic functions of IFN-γ and found that it drives IBD pathogenesis through vascular barrier disruption. Specifically, we show that inhibition of the IFN-γ response in vessels by endothelial-specific knockout of IFN-γ receptor 2 ameliorates experimentally induced colitis in mice. IFN-γ acts pathogenic by causing a breakdown of the vascular barrier through disruption of the adherens junction protein VE-cadherin. Notably, intestinal vascular barrier dysfunction was also confirmed in human IBD patients, supporting the clinical relevance of our findings. Treatment with imatinib restored VE-cadherin/adherens junctions, inhibited vascular permeability, and significantly reduced colonic inflammation in experimental colitis. Our findings inaugurate the pathogenic impact of IFN-γ-mediated intestinal vessel activation in IBD and open new avenues for vascular-directed treatment of this disease.

THU0379 REDUCTION OF ANTERIOR UVEITIS FLARES IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS FOLLOWING ONE YEAR OF TREATMENT WITH CERTOLIZUMAB PEGOL: 48-WEEK INTERIM RESULTS FROM A 96-WEEK OPEN-LABEL STUDY

Background:

Acute anterior uveitis (AAU), inflammation of the anterior uveal tract, is reported in up to 40% of patients (pts) with axial spondyloarthritis (axSpA).1AAU is associated with significant clinical burden; symptoms include blurred vision, photophobia and pain.2Previous studies have shown that TNF inhibitors (TNFi) can reduce AAU flare incidence in pts with radiographic axSpA,3-5but few have focused on pts across the full axSpA spectrum.

Objectives:

To analyse the impact of certolizumab pegol (CZP) treatment on AAU in pts with active radiographic and non-radiographic axSpA and a recent history of AAU.

Methods:

C-VIEW (NCT03020992) is an ongoing multicentre, open-label, phase 4 study. Pts had active axSpA according to the ASAS classification, a history of recurrent AAU (≥2 AAU flares in total and ≥1 AAU flare in the year prior to study entry), were HLA-B27 positive, and were eligible for TNFi treatment (previous failure of ≥2 NSAIDs, biologic naïve or had failed ≤1 TNFi). Pts received CZP 400 mg at Weeks (Wks) 0/2/4, then 200 mg every two wks (Q2W) to Wk 96. The primary variable was incidence of AAU flares compared to historic rates. A pre-specified interim analysis compared AAU incidence in the 48 wks prior to CZP treatment with the 48 wks of treatment, using Poisson regression adjusted for possible within-pt correlations, with period (pre- and post-baseline) and axSpA disease duration as covariates. Incidence rates (IR) were calculated based on the number of cases/pts at risk over 48 wks. Observed data are reported.

Results:

Of 115 enrolled pts, 89 initiated CZP treatment; 85 completed Wk 48. Baseline characteristics are shown in the Table. The 48-wk interim analysis revealed significantly fewer AAU flares/pt during CZP treatment vs before treatment (Figure; Poisson-adjusted IR: 0.2 vs 1.5, p<0.001). The number of pts experiencing 1 and ≥2 AAU flares (64.0% and 31.5% respectively) substantially reduced during CZP treatment (12.4% and 2.2%). After 48 wks CZP treatment, disease activity improved substantially (mean ± SD Ankylosing Spondylitis Disease Activity Score [ASDAS]: 2.0 ± 0.9; Bath Ankylosing Spondylitis Disease Activity Index [BASDAI]: 3.3 ± 2.1), with 31.4% pts achieving ASAS partial remission and 29.1% ASDAS major improvement. No new safety signals were identified.

Table.

Baseline characteristics

CZP 200 mg Q2W (N=89)Age (years), mean ± SD46.5 ± 11.2Male, n (%)56 (62.9)Racial group, n (%) Caucasian87 (97.8) Other2 (2.2)Diagnosis, n (%) Radiographic axSpA76 (85.4) Non-radiographic axSpA13 (14.6)Duration of axSpA (years), mean ± SD8.6 ± 8.4Time since onset of first uveitis flare (years), mean ± SD9.9 ± 9.0ASDAS, mean ± SD3.5 ± 0.9BASDAI, mean ± SD6.5 ± 1.5

Conclusion:

In this open-label study, AAU flare rate significantly reduced in axSpA pts with a history of recurrent AAU during the first 48 wks of CZP. Pts also experienced substantial improvements in axSpA disease activity.

References:

[1]Martin TM. Curr Opin Rheumatol 2002;14:337–41

[2]Bacchiega ABS. Rheumatology (Oxford) 2017;56:2060–7

[3]van der Heijde D. Rheumatology (Oxford) 2017;56:1498–509

[4]van Bentum RE. J Rheumatol 2019;46:153–9

[5]van Denderen JC. J Rheumatol 2014;41:1843–8

Acknowledgments:

This study was funded by UCB Pharma. Editorial services were provided by Costello Medical.

Disclosure of Interests:

Irene van der Horst-Bruinsma Grant/research support from: AbbVie, Novartis, Eli Lilly, Bristol-Myers Squibb, MSD, Pfizer, UCB Pharma, Consultant of: AbbVie, Novartis, Eli Lilly, Bristol-Myers Squibb, MSD, Pfizer, UCB Pharma, Rianne van Bentum: None declared, Frank Verbraak Grant/research support from: Bayer, Novartis, IDxDR, UCB Pharma, Consultant of: Bayer, Novartis, IDxDR, UCB Pharma, Thomas Rath Grant/research support from: AbbVie, Bristol-Myers Squibb, Chugai, Eli Lilly, MSD, Novartis, Pfizer, Roche, UCB Pharma, James Rosenbaum Consultant of: AbbVie, Corvus, Eyevensys, Gilead, Novartis, Janssen, Roche, UCB Pharma; royalties from UpToDate, Maria Misterska-Skora: None declared, Bengt Hoepken Employee of: UCB Pharma, Oscar Irvin-Sellers Employee of: UCB Pharma, Brenda VanLunen Employee of: UCB Pharma, Lars Bauer Employee of: UCB Pharma, Martin Rudwaleit Consultant of: AbbVie, BMS, Celgene, Janssen, Eli Lilly, MSD, Novartis, Pfizer, Roche, UCB Pharma

Functional Molecular Network Analysis Enables Prediction of Response to Vedolizumab Therapy in Anti-TNF Refractory IBD Patients

Background

We applied for the first time 2 label-free technologies, physiological intermolecular modulation spectroscopy (PIMS) and nematic protein organization technic (NPOT) in anti-tumor necrosis factor (TNF) refractory inflammatory bowel disease (IBD) patients to identify clinical responders to vedolizumab therapy and elucidate their underlying functional molecular network.

Methods

PIMS analysis was performed in peripheral blood taken prior to the first vedolizumab application in 20 IBD patients (Crohn disease n = 13; ulcerative colitis n = 7) refractory to at least 1 previous anti-TNF agent therapy. Peripheral blood taken from clinical responders and nonresponders at week 14 of vedolizumab therapy were additionally subjected to NPOT analysis. Response to therapy was assessed by respective clinical disease activity scores (partial Mayo Score and Harvey-Bradshaw Index).

Results

Clinical response to vedolizumab treatment was observed in 7 of 13 Crohn disease and 4 of 7 ulcerative colitis patients at week 14. Response to therapy was accurately predicted by PIMS blood analysis in 100% of ulcerative colitis and 77% of Crohn disease patients. Overall prediction of clinical response with PIMS blood analysis was achieved with a 89% positive predictive value and a 82% negative predictive value. NPOT analysis revealed the heightened expression of the proteins ITGB7, ITGAV, ITG3, PF4, and ASGH in the peripheral blood of vedolizumab responders compared to nonresponders.

Conclusions

PIMS analysis of the blood of anti-TNF refractory IBD patients was able to stratify responders to vedolizumab therapy with high accuracy and specificity. NPOT technology could decipher underling molecular networks in the blood of responders, enabling subsequent personalized therapeutic approaches in IBD.

Use of Fluorescent Dyes in Endoscopy and Diagnostic Investigation

Background

The advancement of innovative endoscopic technology in terms of improving the visualization of the mucosa has been of significant benefit.

Summary

Advancements in image resolution, software processing, and optical filter technology have resulted in several techniques complemental to traditional white light endoscopy. These new techniques provide a real-time optical diagnosis as well as virtual histology of detected lesions. Optical molecular imaging permits a functional assessment within cells.

Key Message

Optical molecular imaging provides an understanding of cellular processes and permits validation of the specificity of fluorescent tracers and the possibility of quantifying the signal.

The TLR9 Agonist Cobitolimod Induces IL10-Producing Wound Healing Macrophages and Regulatory T Cells in Ulcerative Colitis

BACKGROUND AND AIMS

The topically applied Toll-like receptor 9 [TLR9] agonist cobitolimod is a first-in-class DNA-based oligonucleotide with demonstrated therapeutic efficacy in clinical trials with ulcerative colitis [UC] patients. We here characterized its anti-inflammatory mechanism in UC.

METHODS

Luminal cobitolimod administration was evaluated in an experimental dextran sodium sulfate [DSS]-induced colitis model. Cultured blood and mucosal cells from UC patients were treated with cobitolimod and analysed via microarray, quantitative real-time PCR, ELISA and flow cytometry. Intestinal slides of cobitolimod-treated UC patients were analysed by immunohistochemistry.

RESULTS

Cobitolimod administration markedly suppressed experimental colitis activity, and microarray analyses demonstrated mucosal IL10 upregulation and suppression of IL17 signalling pathways. Cobitolimod treatment was associated with significant induction of mucosal IL10+Tr1 and Treg cells and suppression of Th17 cells. TLR9 knockout mice indicated that cobitolimod requires TLR9 signalling for IL10 induction. In UC patients, mucosal TLR9 levels correlated with severity of inflammation. Cobitolimod inhibited IL17A and IL17F, but increased IL10 and FoxP3 expression in cultured intestinal UC T cells. Cobitolimod-mediated suppression of intestinal IL17+T cells was abrogated by IL10 blockade. Furthermore, cobitolimod led to heightened IL10 production by wound healing macrophages. Immunohistochemistry in intestinal biopsies of cobitolimod-treated UC patients indicated increased presence of IL10+mononuclear and regulatory T cells, as well as reduction of IL17+cells.

CONCLUSION

Activation of TLR9 via cobitolimod might represent a novel therapeutic approach in UC, as it suppresses Th17 cells and induces anti-inflammatory IL10+macrophages and regulatory T cells, thereby modifying the dysregulated intestinal cytokine balance.

PODCAST

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

Retrograde inspection vs standard forward view for the detection of colorectal adenomas during colonoscopy: A back-to-back randomized clinical trial

BACKGROUND

The adenoma detection rate (ADR) is inversely associated with the incidence of interval colorectal cancer and serves as a benchmark quality criterion during screening colonoscopy. However, adenoma miss rates reach up to 26% and studies have shown that a second inspection of the right colon in retroflected view (RFV) can increase ADR.

AIM

To assess whether inspection of the whole colon in RFV compared to standard forward view (SFV) can increase ADR.

METHODS

Patients presenting for screening or surveillance colonoscopy were invited to participate in this randomized controlled trial and randomized into two arms. In RFV arm colonoscopy was initially performed with SFV, followed by a second inspection of the whole colon in RFV. In the SFV arm first withdrawal was performed with SFV, followed by a second inspection of the whole colon again with SFV. Number, size and morphology of polyps found during first and second inspection in each colonic segment were recorded and all polyps were removed and sent for histopathology in separate containers.

RESULTS

Two hundred and five patients were randomly assigned to the RFV (n = 101) and SFV (n = 104) arm. In the RFV arm, both polyp detection rate (PDR) and ADR were increased under second inspection in RFV (PDR 1^st SFV: 39.8%, PDR 2^nd RFV: 46.6%; ADR 1^st SFV: 35.2%, ADR 2^nd RFV: 42%). Likewise, in the SFV arm, PDR and ADR were increased under second inspection (PDR 1^st SFV: 37.5%, PDR 2^nd SFV: 46.6%; ADR 1^st SFV: 34.1%, ADR 2^nd SFV: 44.3%) with no significant differences in ADR and PDR between the SFV and RFV arm. Mean number of adenomas per patient (APP) was increased in the RFV and SFV (APP RFV arm: 1^st SFV: 1.71; 2^nd RFV: 2.38; APP SFV arm: 1^st SFV: 1.83, 2^nd SFV:2.2). The majority of adenomas additionally found during second inspection in RFV or in SFV were located in the transverse and left-sided colon and were > 5 mm in size.

CONCLUSION

Second inspection of the whole colon leads to increased adenoma detection with no differences between SFV and RFV. Hence, increased detection is most likely a feature of the second inspection itself but not of the inspection mode.

Non-classical monocyte homing to the gut via α4β7 integrin mediates macrophage-dependent intestinal wound healing

OBJECTIVE

To study the role of α4β7 integrin for gut homing of monocytes and to explore the biological consequences of therapeutic α4β7 inhibition with regard to intestinal wound healing.

DESIGN

We studied the expression of homing markers on monocyte subsets in the peripheral blood and on macrophage subsets in the gut of patients with IBD and controls with flow cytometry and immunohistochemistry. Integrin function was addressed with dynamic adhesion assays and in vivo gut homing assays. In vivo wound healing was studied in mice deficient for or depleted of α4β7 integrin.

RESULTS

Classical and non-classical monocytes were clearly dichotomous regarding homing marker expression including relevant expression of α4β7 integrin on human and mouse non-classical monocytes but not on classical monocytes. Monocyte-expressed α4β7 integrin was functionally important for dynamic adhesion to mucosal vascular addressin cell adhesion molecule 1 and in vivo gut homing. Impaired α4β7-dependent gut homing was associated with reduced (effect size about 20%) and delayed wound healing and suppressed perilesional presence of wound healing macrophages. Non-classical monocytes in the peripheral blood were increased in patients with IBD under clinical treatment with vedolizumab.

CONCLUSION

In addition to reported effects on lymphocytes, anti-α4β7 therapy in IBD also targets non-classical monocytes. Impaired gut homing of such monocytes might lead to a reduction of wound healing macrophages and could potentially explain increased rates of postoperative complications in vedolizumab-treated patients, which have been observed in some studies.

Advanced Endoscopic Imaging in Colonic Neoplasia

Background

Endoscopic imaging is a rapidly evolving field with a constant influx of new concepts and technologies. Since the introduction of video endoscopy and subsequently high-definition imaging as the first revolutions in gastrointestinal endoscopy, several technologies of virtual chromoendoscopy have been developed and brought to the market in the past decade, which have shaped and revolutionized for a second time our approach to endoscopic imaging. In parallel to these developments, microscopic imaging technologies, such as endomicroscopy and endocytoscopy, allow us to examine single cells within the mucosa in real time, thereby enabling histological diagnoses during ongoing endoscopy.

Summary

In this review, we provide an overview on the technical background of different technologies of advanced endoscopic imaging, and then review and discuss their role and applications for the diagnosis and management of colorectal neoplasms as well as limitations and challenges that exist despite all technological improvements.

Key Messages

Technologies of advanced endoscopic imaging have profound impact not only on our imaging capabilities, they are also about to fundamentally change our approach to managing lesions in the gastrointestinal tract: not every lesion found during colonoscopy has to be excised or sent for histopathologic evaluation. However, before this becomes widespread reality, major obstacles such as patient acceptance, adoption by less trained endoscopists, and also legal aspects need to carefully addressed. The development of computer-aided diagnosis and artificial intelligence algorithms hold the potential to overcome the obstacles associated with the concept of optical biopsy and will most likely fundamentally facilitate, shape, and change decision making in the management of colorectal lesions.

Magnification endoscopy with optical chromoendoscopy shows strong correlation with histologic inflammation in patients with inflammatory bowel disease

Background and study aims  Apart from mucosal healing as an established treatment goal in inflammatory bowel diseases (IBD), recent evidence suggests that histologic healing may become another key prognostic parameter in IBD patients. We aimed to evaluate whether magnification endoscopy with optical chromoendoscopy can accurately assess histologic inflammation in IBD patients. Patients and methods  In this prospective study, 82 patients with IBD (30 UC, 52 CD) were included. In all patients, magnification endoscopy in conjunction with optical chromoendoscopy was performed and rated on a novel magnification endoscopy score by three independent endoscopists. Targeted biopsies of the imaged areas were obtained and results were compared against two histological scores in UC (Robarts Histopathology Index, RHI; Nancy Histology Index, NHI) and one score in CD (modified Riley index, mRI). Moreover, interobserver agreement was calculated. Results  Magnification endoscopy showed strong correlation with histopathologic scoring in both UC (RHI: r = 0.83, NHI: r = 0.78, P  < 0.05) and CD (mRI: r = 0.74, P  < 0.05) with high accuracy, sensitivity, and specificity. Further, 25 % of patients with mucosal healing on standard endoscopy showed signs of microinflammation on magnification endoscopy with optical chromoendoscopy, while none of the patients with mucosal and vascular healing under magnification endoscopy with optical chromoendoscopy exhibited microscopic inflammation. Interobserver agreement for grading intestinal inflammation by magnification endoscopy with optical chromoendoscopy was substantial (κ > 0.7). Conclusion  Magnification endoscopy in combination with optical chromoendoscopy shows strong correlation with histologic inflammation in patients with IBD. This approach has potential to reduce physical biopsies for monitoring of inflammatory activity in patients with IBD during colonoscopy.

Targeting mucosal healing in Crohn's disease: what the clinician needs to know

In recent years, mucosal healing has emerged as a key therapeutic goal in the clinical management of patients with Crohn's disease, as it has been associated with improved long-term clinical outcomes. With the vast improvements in endoscopic imaging techniques and the increase in available treatment options, which reportedly are able to induce mucosal healing, the practising physician is left to wonder: how is endoscopic mucosal healing exactly defined in Crohn's disease, and how can it effectively be achieved and monitored in daily clinical practice? Within this review, we will give an overview of the ongoing debate about the definition of mucosal healing and the modalities to monitor inflammation, and finally present available therapies with the capacity to induce mucosal healing.