Perianal fistulising Crohn's disease: utilising the TOpClass classification in clinical practice to provide targeted individualised care.

BACKGROUND AND AIMS: Perianal fistulation is a challenging phenotype of Crohn's disease with significant impact on quality of life. Historically, fistulae have been classified anatomically in relation to the sphincter complex, and management guidelines have been generalised, with lack of attention to the clinical heterogenicity seen. The recent 'TOpClass classification system' for perianal fistulising Crohn's disease (PFCD) addresses this issue, and classifies patients into defined groups, which provide a focus for fistula management that aligns with disease characteristics and patient goals. In this article, we discuss the clinical applicability of the TOpClass model and provide direction on its use in clinical practice. METHODS: An international group of perianal clinicians participated in an expert consensus to define how the TOpClass system can be incorporated into real-life practice. This included gastroenterologists, IBD surgeons, and radiologists specialised in PFCD. The process was informed by the multi-disciplinary team management of eight high-volume fistula centres in North America, Europe, and Australia. RESULTS: The process produced position statements to accompany the classification system and guide PFCD management. The statements range from the management of patients with quiescent perianal disease to those with severe PFCD requiring diverting-ostomy and/or proctectomy. The optimisation of medical therapies, as well as the use of surgery, in fistula closure and symptom management is explored across each classification group. CONCLUSION: This article provides an overview of the system's use in clinical practice. It aims to enable clinicians to have a pragmatic and patient-goal centred approach to medical and surgical management options for individual patients with PFCD.

Preoperative optimization: Review on nutritional assessment and strategies in IBD.

Inflammatory bowel diseases (IBD), encompassing conditions like Crohn's disease and ulcerative colitis, present multifaceted challenges requiring a comprehensive management approach. Patients often necessitate a combination of medical therapy, surgical interventions, and nutritional support. Despite advancements in medical and dietary therapies, the prevalence of surgery remains high among the IBD population, alongside the persistent risk of malnutrition. Preoperative nutritional optimization has thus become a critical element in the perioperative pathway, given its association with improved surgical outcomes. However, standardized protocols for preoperative optimization of IBD patients are lacking, and available data are mainly retrospective. This review provides an overview of the current knowledge on preoperative nutritional screening and optimization in IBD patients and identifies avenues for future research and clinical practice. Interdisciplinary collaboration among healthcare professionals, including gastroenterologists, surgeons, dietitians, physiotherapists, and psychologists, is crucial for comprehensive preoperative nutritional management in IBD patients. By addressing the interplay between inflammation, malnutrition, and surgical risk, clinicians can strive to enhance surgical care and postoperative outcomes. In conclusion, while recognizing the importance of preoperative nutritional optimization in improving surgical outcomes for IBD patients, challenges persist in standardizing management protocols. Prospective studies are needed to establish such protocols and evaluate the effectiveness of different nutritional strategies.

Intercellular interaction between FAP+ fibroblasts and CD150+ inflammatory monocytes mediates fibrostenosis in Crohn's disease.

Crohn's disease (CD) is marked by recurring intestinal inflammation and tissue injury, often resulting in fibrostenosis and bowel obstruction, necessitating surgical intervention with high recurrence rates. To elucidate the mechanisms underlying fibrostenosis in CD, we analyzed the transcriptome of cells isolated from the transmural ileum of patients with CD, including a trio of lesions from each patient: non-affected, inflamed, and stenotic ileum samples, and compared them with samples from patients without CD. Our computational analysis revealed that profibrotic signals from a subset of monocyte-derived cells expressing CD150 induced a disease-specific fibroblast population, resulting in chronic inflammation and tissue fibrosis. The transcription factor TWIST1 was identified as a key modulator of fibroblast activation and extracellular matrix (ECM) deposition. Genetic and pharmacological inhibition of TWIST1 prevents fibroblast activation, reducing ECM production and collagen deposition. Our findings suggest that the myeloid-stromal axis may offer a promising therapeutic target to prevent fibrostenosis in CD.

Perianal Fistulizing Crohn's Disease-Associated Anorectal and Fistula Cancers: Systematic Review and Expert Consensus.

BACKGROUND & AIMS: Perianal fistulizing Crohn's disease (PFCD)-associated anorectal and fistula cancers are rare but often devastating diagnoses. However, given the low incidence and consequent lack of data and clinical trials in the field, there is little to no guidance on screening and management of these cancers. To inform clinical practice, we developed consensus guidelines on PFCD-associated anorectal and fistula cancers by multidisciplinary experts from the international TOpClass consortium. METHODS: We conducted a systematic review by standard methodology, using the Newcastle-Ottawa Scale quality assessment tool. We subsequently developed consensus statements using a Delphi consensus approach. RESULTS: Of 561 articles identified, 110 were eligible, and 76 articles were included. The overall quality of evidence was low. The TOpClass consortium reached consensus on 6 structured statements addressing screening, risk assessment, and management of PFCD-associated anorectal and fistula cancers. Patients with long-standing (>10 years) PFCD should be considered at small but increased risk of developing perianal cancer, including squamous cell carcinoma of the anus and anorectal carcinoma. Risk factors for squamous cell carcinoma of the anus, notably human papilloma virus, should be considered. New, refractory, or progressive perianal symptoms should prompt evaluation for fistula cancer. There was no consensus on timing or frequency of screening in patients with asymptomatic perianal fistula. Multiple modalities may be required for diagnosis, including an examination under anesthesia with biopsy. Multidisciplinary team efforts were deemed central to the management of fistula cancers. CONCLUSIONS: Inflammatory bowel disease clinicians should be aware of the risk of PFCD-associated anorectal and fistula cancers in all patients with PFCD. The TOpClass consortium consensus statements outlined herein offer guidance in managing this challenging scenario.

ECCO Guidelines on Therapeutics in Crohn's Disease: Surgical Treatment.

This article is the second in a series of two publications on the European Crohn's and Colitis Organisation [ECCO] evidence-based consensus on the management of Crohn's disease. The first article covers medical management; the present article addresses surgical management, including preoperative aspects and drug management before surgery. It also provides technical advice for a variety of common clinical situations. Both articles together represent the evidence-based recommendations of the ECCO for Crohn's disease and an update of prior ECCO guidelines.

A global consensus on the definitions, diagnosis and management of fibrostenosing small bowel Crohn's disease in clinical practice.

Fibrostenosis of the small bowel is common in patients with Crohn's disease. No consensus recommendations on definition, diagnosis and management in clinical practice are currently available. In this Consensus Statement, we present a clinical practice RAND/UCLA appropriateness study on the definition, diagnosis and clinical management of fibrostenosing Crohn's disease. It was conducted by a panel of 28 global experts and one patient representative. Following a systematic literature review, 526 candidate items grouped into 136 questions were generated and subsequently evaluated for appropriateness. Strictures are best defined as wall thickening, luminal narrowing and prestenotic dilation. Cross-sectional imaging is required for accurate diagnosis of fibrostenosing Crohn's disease, and it is recommended before making treatment decisions. It should also assess the degree of inflammation in the bowel wall. Multiple options for medical anti-inflammatory, endoscopic and surgical therapies were suggested, including follow-up strategies following therapy. This Consensus Statement supports clinical practice through providing guidance on definitions, diagnosis and therapeutic management of patients with fibrostenosing small bowel Crohn's disease.

Efficacy and Safety of Ustekinumab for Chronic Pouchitis: A Prospective Open-label Multicenter Study.

BACKGROUND & AIMS: Seventeen percent of patients with ulcerative colitis that undergo proctocolectomy with pouch surgery will develop chronic pouchitis. We evaluated the efficacy of ustekinumab for these patients. METHODS: We performed a prospective study of patients with chronic pouchitis receiving ustekinumab intravenously at baseline (∼6 mg/kg) and 90 mg ustekinumab subcutaneously every 8 weeks thereafter. The Modified Pouchitis Disease Activity Index (mPDAI) was assessed at baseline and weeks 16 and 48. The primary endpoint was the proportion of patients achieving steroid-free remission (mPDAI <5 and reduction by ≥2 points) at week 16. Secondary endpoints included the proportion of patients achieving remission at week 48, the proportion of patients achieving response (reduction of mPDAI by ≥2 points) at weeks 16 and 48, and change in mPDAI. RESULTS: We enrolled 22 patients (59% male; median age, 42.2 years). Remission was achieved in 27.3% at week 16 and 36.4% at week 48. Response was achieved in 54.5% both at weeks 16 and 48. The median mPDAI decreased from 8 (interquartile range [IQR], 7-10) to 7 (IQR, 4-9) at week 16 (P = .007) and 4 (IQR, 1.75-7.25) at week 48 (P < .001). The clinical mPDAI subscore decreased from 3.5 (IQR, 2-4) to 2 (IQR, 1-3) at week 16 (P = .009) and 1 (IQR, 0-2.25) at week 48 (P = .001). The endoscopic mPDAI subscore decreased from 5.5 (IQR, 4-6) to 4 (IQR, 3-6) at week 16 (P = .032) and 3 (IQR, 1.75-4.25) at week 48 (P = .001). CONCLUSION: Ustekinumab was efficacious in one-half of the patients suffering from chronic pouchitis. Ustekinumab should therefore be positioned in the treatment algorithm of chronic pouchitis. (ClinicalTrials.gov Number NCT04089345).

Fibrostricturing Crohn's Disease Is Marked by an Increase in Active Eosinophils in the Deeper Layers.

INTRODUCTION: Approximately 50% of patients with Crohn's disease (CD) develop intestinal strictures necessitating surgery. The immune cell distribution in these strictures remains uncharacterized. We aimed to identify the immune cells in intestinal strictures of patients with CD. METHODS: During ileocolonic resections, transmural sections of terminal ileum were sampled from 25 patients with CD and 10 non-inflammatory bowel disease controls. Macroscopically unaffected, fibrostenotic, and inflamed ileum was collected and analyzed for immune cell distribution (flow cytometry) and protein expression. Collagen deposition was assessed through a Masson Trichrome staining. Eosinophil and fibroblast colocalization was assessed through immunohistochemistry. RESULTS: The Masson Trichrome staining confirmed augmented collagen deposition in both the fibrotic and the inflamed regions, though with a significant increased collagen deposition in the fibrotic compared with inflamed tissue. Distinct Th1, Th2, regulatory T cells, dendritic cells, and monocytes were identified in fibrotic and inflamed CD ileum compared with unaffected ileum of patients with CD as non-inflammatory bowel disease controls. Only minor differences were observed between fibrotic and inflamed tissue, with more active eosinophils in fibrotic deeper layers and increased eosinophil cationic protein expression in inflamed deeper layers. Last, no differences in eosinophil and fibroblast colocalization were observed between the different regions. DISCUSSION: This study characterized immune cell distribution and protein expression in fibrotic and inflamed ileal tissue of patients with CD. Immunologic, proteomic, and histological data suggest inflammation and fibrosis are intertwined, with a large overlap between both tissue types. However strikingly, we did identify an increased presence of active eosinophils only in the fibrotic deeper layers, suggesting their potential role in fibrosis development.

Disease Acceptance, but not Perceived Control, is Uniquely Associated with Inflammatory Bowel Disease-related Disability.

BACKGROUND AND AIMS: Disability, an important aspect of disease burden in patients with inflammatory bowel disease [IBD], has been suggested as a valuable clinical endpoint. We aimed to investigate how disease acceptance and perceived control, two psychological predictors of subjective health, are associated with IBD-related disability. METHODS: In this cross-sectional study, adult IBD patients from the University Hospitals Leuven received a survey with questions about clinical and demographic characteristics, disease acceptance and perceived control [Subjective Health Experience model questionnaire], and IBD-related disability [IBD Disk]. Multiple linear regressions assessed predictors of IBD-related disability in the total sample and in the subgroups of patients in clinical remission or with active disease. RESULTS: In the total sample (N = 1250, 54.2% female, median [interquartile range: IQR] age 51 [39-61] years, 61.3% Crohn's disease, 34.9% active disease), adding the psychological predictors to the model resulted in an increased explained variance in IBD-related disability of 19% compared with a model with only demographic and clinical characteristics [R2adj 38% vs 19%, p <0.001]. The increase in explained variance was higher for patients in clinical remission [ΔR2adj 20%, p <0.001] compared with patients with active disease [ΔR2adj 10%, p <0.001]. Of these predictors, disease acceptance was most strongly associated with disability in the total sample [ß = -0.44, p <0.001], as well as in both subgroups [ß = -0.47, p <0.001 and ß = -0.31, p <0.001 respectively]. Perceived control was not significantly associated with disability when accounting for all other predictors. CONCLUSIONS: Disease acceptance is strongly associated with IBD-related disability, supporting further research into disease acceptance as a treatment target.

Accuracy of Information given by ChatGPT for Patients with Inflammatory Bowel Disease in Relation to ECCO Guidelines.

BACKGROUND: As acceptance of artificial intelligence [AI] platforms increases, more patients will consider these tools as sources of information. The ChatGPT architecture utilizes a neural network to process natural language, thus generating responses based on the context of input text. The accuracy and completeness of ChatGPT3.5 in the context of inflammatory bowel disease [IBD] remains unclear. METHODS: In this prospective study, 38 questions worded by IBD patients were inputted into ChatGPT3.5. The following topics were covered: [1] Crohn's disease [CD], ulcerative colitis [UC], and malignancy; [2] maternal medicine; [3] infection and vaccination; and [4] complementary medicine. Responses given by ChatGPT were assessed for accuracy [1-completely incorrect to 5-completely correct] and completeness [3-point Likert scale; range 1-incomplete to 3-complete] by 14 expert gastroenterologists, in comparison with relevant ECCO guidelines. RESULTS: In terms of accuracy, most replies [84.2%] had a median score of ≥4 (interquartile range [IQR]: 2) and a mean score of 3.87 [SD: ±0.6]. For completeness, 34.2% of the replies had a median score of 3 and 55.3% had a median score of between 2 and <3. Overall, the mean rating was 2.24 [SD: ±0.4, median: 2, IQR: 1]. Though groups 3 and 4 had a higher mean for both accuracy and completeness, there was no significant scoring variation between the four question groups [Kruskal-Wallis test p > 0.05]. However, statistical analysis for the different individual questions revealed a significant difference for both accuracy [p < 0.001] and completeness [p < 0.001]. The questions which rated the highest for both accuracy and completeness were related to smoking, while the lowest rating was related to screening for malignancy and vaccinations especially in the context of immunosuppression and family planning. CONCLUSION: This is the first study to demonstrate the capability of an AI-based system to provide accurate and comprehensive answers to real-world patient queries in IBD. AI systems may serve as a useful adjunct for patients, in addition to standard of care in clinics and validated patient information resources. However, responses in specialist areas may deviate from evidence-based guidance and the replies need to give more firm advice.

Crohn's Patient Serum Proteomics Reveals Response Signature for Infliximab but not Vedolizumab.

BACKGROUND: Crohn's disease is a chronic inflammatory bowel disease that affects the gastrointestinal tract. Common biologic families used to treat Crohn's are tumor necrosis factor (TNF)-α blockers (infliximab and adalimumab) and immune cell adhesion blockers (vedolizumab). Given their differing mechanisms of action, the ability to monitor response and predict treatment efficacy via easy-to-obtain blood draws remains an unmet need. METHODS: To investigate these gaps in knowledge, we leveraged 2 prospective cohorts (LOVE-CD, TAILORIX) and profiled their serum using high-dimensional isobaric-labeled proteomics before treatment and 6 weeks after treatment initiation with either vedolizumab or infliximab. RESULTS: The proportion of patients endoscopically responding to treatment was comparable among infliximab and vedolizumab cohorts; however, the impact of vedolizumab on patient sera was negligible. In contrast, infliximab treatment induced a robust response including increased blood-gas regulatory response proteins, and concomitant decreases in inflammation-related proteins. Further analysis comparing infliximab responders and nonresponders revealed a lingering innate immune enrichments in nonresponders and a unique protease regulation signature related to clotting cascades in responders. Lastly, using samples prior to infliximab treatment, we highlight serum protein biomarkers that potentially predict a positive response to infliximab treatment. CONCLUSIONS: These results will positively impact the determination of appropriate patient treatment and inform the selection of clinical trial outcome metrics.

Endoscopic and Histological Placebo Rates in Crohn's Disease Clinical Trials: A Systematic Review and Meta-analysis.

BACKGROUND: Precise estimates of placebo response rates help efficient clinical trial design. In this systematic review and meta-analysis, we assessed contemporary placebo endoscopic and histological response rates in Crohn's disease (CD) clinical trials. METHODS: MEDLINE, EMBASE, and Cochrane CENTRAL were searched from inception to April 2022 to identify placebo-controlled studies of pharmacological interventions for CD. Endoscopic response, remission, and mucosal healing rates for participants assigned to placebo in induction and maintenance studies were pooled using a random-effects model. Point estimates and associated 95% confidence intervals (CIs) were calculated. RESULTS: In total, 16 studies (11 induction, 3 maintenance, 2 induction and maintenance) that randomized 1646 participants to placebo were eligible. For induction trials, the pooled placebo endoscopic response, endoscopic remission, and mucosal healing rates in participants assigned to placebo were 13% (95% CI, 10-16; I2 = 14.1%; P = .14), 6% (95% CI, 3-11; I2 = 74.7%; P < .001), and 6% (95% CI, 4-9; I2 = 26.9%; P = .29), respectively. The pooled endoscopic remission rate in patients who were bio-naïve was 10% (95% CI, 4-23) compared with only 4% (95% CI, 3-7) in bio-experienced patients. For maintenance trials, the pooled endoscopic response, remission, and mucosal healing rates were 7% (95% CI, 1-31; I2 = 78.2%; P = .004), 11% (95% CI, 4-27; I2 = 70.8%; P = .06), and 7% (95% CI, 3-15; I2 = 29.7; P = .23), respectively. Only 3 trials assessed histological outcomes. CONCLUSIONS: Endoscopic placebo rates vary according to trial phase and prior biologic exposure. These contemporary data will serve to inform CD trial design, sample size calculation, and end point selection for future trials.

Dysbiosis and Associated Stool Features Improve Prediction of Response to Biological Therapy in Inflammatory Bowel Disease.

BACKGROUND & AIMS: Dysbiosis of the gut microbiota is considered a key contributor to inflammatory bowel disease (IBD) etiology. Here, we investigated potential associations between microbiota composition and the outcomes to biological therapies. METHODS: The study prospectively recruited 296 patients with active IBD (203 with Crohn's disease, 93 with ulcerative colitis) initiating biological therapy. Quantitative microbiome profiles of pretreatment and posttreatment fecal samples were obtained combining flow cytometry with 16S amplicon sequencing. Therapeutic response was assessed by endoscopy, patient-reported outcomes, and changes in fecal calprotectin. The effect of therapy on microbiome variation was evaluated using constrained ordination methods. Prediction of therapy outcome was performed using logistic regression with 5-fold cross-validation. RESULTS: At baseline, 65.9% of patients carried the dysbiotic Bacteroides2 (Bact2) enterotype, with a significantly higher prevalence among patients with ileal involvement (76.8%). Microbiome variation was associated with the choice of biological therapy rather than with therapeutic outcome. Only anti-tumor necrosis factor-α treatment resulted in a microbiome shift away from Bact2, concomitant with an increase in microbial load and butyrogen abundances and a decrease in potentially opportunistic Veillonella. Remission rates for patients hosting Bact2 at baseline were significantly higher with anti-tumor necrosis factor-α than with vedolizumab (65.1% vs 35.2%). A prediction model, based on anthropometrics and clinical data, stool features (microbial load, moisture, and calprotectin), and Bact2 detection predicted treatment outcome with 73.9% accuracy for specific biological therapies. CONCLUSION: Fecal characterization based on microbial load, moisture content, calprotectin concentration, and enterotyping may aid in the therapeutic choice of biological therapy in IBD.

The assessment of segmental healing by the Modified Mayo Endoscopic Score (MMES) complements the prediction of long-term clinical outcomes in patients with ulcerative colitis.

BACKGROUND AND AIMS: Current endoscopic scoring systems for ulcerative colitis (UC) do not consider the extent of mucosal inflammation. The modified Mayo endoscopic score (MMES) was developed to detect segmental endoscopic improvement. We evaluated the ability of the MMES to predict long-term clinical outcomes and compared it to the widely used Mayo endoscopic subscore (MES). METHODS: Consecutive patients with moderate to severe UC starting biological therapy were enrolled between January 2014 and September 2017 in this prospective observational study. A clinical and endoscopic evaluation was performed at baseline and at week 8/14. A modified Mayo score was used to grade clinical activity, MES and MMES were used to evaluate endoscopic activity. Patients were divided into 3 groups according to the evolution of endoscopic activity, namely endoscopic improvement (MES ≤ 1), segmental endoscopic response only (MES > 1, but decrease in MMES ≥ 30%) or no endoscopic response (all others). Over the follow-up period clinical relapse-, discontinuation- and colectomy-free survival were assessed. RESULTS: A total of 150 patients were included (48% female, median age 42 years, median disease duration 7 years) with a median follow-up of 61 months. We identified 69 patients with endoscopic improvement, 27 with segmental endoscopic response and 54 without endoscopic response. Patients with segmental endoscopic response showed intermediate long-term clinical outcomes as compared to the other two groups (log rank p = 0.003 for clinical relapse-, and p < 0.001 for both discontinuation- and colectomy-free survival). CONCLUSIONS: The MMES exhibited a benefit in predicting long-term outcome in UC even though endoscopic improvement remains the strongest predictor.

Role of artificial intelligence in imaging and endoscopy for the diagnosis, monitoring and prognostication of inflammatory bowel disease: a scoping review protocol.

INTRODUCTION: Inflammatory bowel diseases (IBD) are immune-mediated conditions that are increasing in incidence and prevalence worldwide. Their assessment and monitoring are becoming increasingly important, though complex. The best disease control is achieved through tight monitoring of objective inflammatory parameters (such as serum and stool inflammatory markers), cross-sectional imaging and endoscopic assessment. Considering the complexity of the information obtained throughout a patient's journey, artificial intelligence (AI) provides an ideal adjunct to existing tools to help diagnose, monitor and predict the course of disease of patients with IBD. Therefore, we propose a scoping review assessing AI's role in diagnosis, monitoring and prognostication tools in patients with IBD. We aim to detect gaps in the literature and address them in future research endeavours. METHODS AND ANALYSIS: We will search electronic databases, including Medline, Embase, Cochrane CENTRAL, CINAHL Complete, Web of Science and IEEE Xplore. Two reviewers will independently screen the abstracts and titles first and then perform the full-text review. A third reviewer will resolve any conflict. We will include both observational studies and clinical trials. Study characteristics will be extracted using a data extraction form. The extracted data will be summarised in a tabular format, following the imaging modality theme and the study outcome assessed. The results will have an accompanying narrative review. ETHICS AND DISSEMINATION: Considering the nature of the project, ethical review by an institutional review board is not required. The data will be presented at academic conferences, and the final product will be published in a peer-reviewed journal.

Effect of anastomotic configuration on Crohn's disease recurrence after primary ileocolic resection: a comparative monocentric study of end-to-end versus side-to-side anastomosis.

There is ongoing debate whether the type of anastomosis following intestinal resection for Crohn's disease (CD) can impact on complications and postoperative recurrence. The aim of the present study is to describe the outcomes of side-to-side (S-S) vs end-to-end (E-E) anastomosis after ileocecal resection for CD. A retrospective comparative study was conducted in consecutive CD patients who underwent primary ileocecal resection between 2005 and 2013. All patients underwent colonoscopy 6 months postoperatively to assess endoscopic recurrence, defined as Rutgeerts' score (RS) ≥ i2. Surgical recurrence implied reoperation due to CD activity at the anastomotic site. Modified surgical recurrence was defined as the need for reoperation or balloon-dilation. Perioperative factors related to recurrence were evaluated. Of the 127 patients included, 51 (40.2%) received an E-E anastomosis. Median follow-up was longer in the E-E group (8.62 vs 13.68 years). Apart from the microscopic resection margins, patient, disease and surgical characteristics were similar between both groups. Anastomotic complications were comparable (S-S 5.3% vs E-E 5.8%, p = 1.00)0. Postoperatively, biologicals were used in 55.3% and 62.7% (p = 0.47) in S-S and E-E patients, respectively. Endoscopic recurrence did not differ between S-S and E-E patients (78.9 vs 72.9%, p = 0.37), with no significant difference in RS values between both groups (p = 0.87). Throughout follow-up, a higher surgical (p = 0.04) and modified surgical recurrence (p = 0.002) rate was observed in the E-E anastomosis group. Type of anastomosis was an independent risk factor for modified surgical recurrence. The type of anastomosis did not influence endoscopic recurrence and immediate postoperative disease complications. However, the wide diameter and the morphologic characteristic of the stapled S-S anastomosis resulted in a significant reduced risk for surgical and endoscopic reintervention on the long term.

IL-12 and IL-23 pathway inhibition in inflammatory bowel disease.

Interleukin-12 (IL-12) and interleukin-23 (IL-23), which belong to the IL-12 family of cytokines, have a key role in intestinal homeostasis and inflammation and are implicated in the pathogenesis of inflammatory bowel disease. Upon their secretion by antigen-presenting cells, they exert both pro-inflammatory and anti-inflammatory receptor-mediated effects. An increased understanding of these biological effects, particularly the pro-inflammatory effects mediated by IL-12 and IL-23, has led to the development of monoclonal antibodies that target a subunit common to IL-12 and IL-23 (p40; targeted by ustekinumab and briakinumab), or the IL-23-specific subunit (p19; targeted by risankizumab, guselkumab, brazikumab and mirikizumab). This Review provides a summary of the biology of the IL-12 family cytokines IL-12 and IL-23, discusses the role of these cytokines in intestinal homeostasis and inflammation, and highlights IL-12- and IL-23-directed drug development for the treatment of Crohn's disease and ulcerative colitis.

Results of the Eighth Scientific Workshop of ECCO: Pathophysiology and Risk Factors of Postoperative Crohn's Disease Recurrence after an Ileocolonic Resection.

Postoperative recurrence [POR] after an ileocolonic resection with ileocolonic anastomosis is frequently encountered in patients with Crohn's disease. The 8th Scientific Workshop of ECCO reviewed the available evidence on the pathophysiology and risk factors for POR. In this paper, we discuss published data on the role of the microbiome, the mesentery, the immune system and the genetic background. In addition to investigating the causative mechanisms of POR, identification of risk factors is essential to tailor preventive strategies. Potential clinical, surgical and histological risk factors are presented along with their limitations. Emphasis is placed on unanswered research questions, guiding prevention of POR based on individual patient profiles.