Myenteric plexitis is a risk factor for endoscopic and clinical postoperative recurrence after ileocolonic resection in Crohn's disease

Histological Image-based Ensemble Model to Identify Myenteric Plexitis and Predict Endoscopic Postoperative Recurrence in Crohn's Disease: A Multicentre, Retrospective Study

BACKGROUND AND AIMS

Myenteric plexitis is correlated with postoperative recurrence of Crohn's disease when relying on traditional statistical methods. However, comprehensive assessment of myenteric plexus remains challenging. This study aimed to develop and validate a deep learning system to predict postoperative recurrence through automatic screening and identification of features of the muscular layer and myenteric plexus.

METHODS

We retrospectively reviewed 205 patients who underwent bowel resection surgery from two hospitals. Patients were divided into a training cohort [n = 108], an internal validation cohort [n = 47], and an external validation cohort [n = 50]. A total of 190 960 patches from 278 whole-slide images of surgical specimens were analysed using the ResNet50 encoder, and 6144 features were extracted after transfer learning. We used five robust algorithms to construct classification models. The performances of the models were evaluated based on the area under the receiver operating characteristic curve [AUC] in three cohorts.

RESULTS

The stacking model achieved satisfactory accuracy in predicting postoperative recurrence of CD in the training cohort (AUC: 0.980; 95% confidence interval [CI] 0.960-0.999), internal validation cohort [AUC: 0.908; 95% CI 0.823-0.992], and external validation cohort [AUC: 0.868; 95% CI 0.761-0.975]. The accuracy for identifying the severity of myenteric plexitis was 0.833, 0.745, and 0.694 in the training, internal validation and external validation cohorts, respectively.

CONCLUSIONS

Our work initially established an interpretable stacking model based on features of the muscular layer and myenteric plexus extracted from histological images to identify the severity of myenteric plexitis and predict postoperative recurrence of CD.

Management of Post-Operative Crohn's Disease: Knowns and Unknowns

Crohn's disease (CD) is a chronic inflammatory disorder of the gastrointestinal tract characterized by relapsing-remission phases. CD often requires surgical intervention during its course, mainly ileo-cecal/ileo-colonic resection. However, surgery in CD is not curative and post-operative recurrence (POR) can happen. The management of CD after surgery presents challenges. Ensuring timely, effective, and safe therapy to prevent POR is essential but difficult, considering that approximately 20-30% of subjects may not experience endoscopic POR and that 40-50% will only exhibit intermediate lesions, which carry a low risk of mid- and long-term clinical and surgical POR. Currently, there are two accepted intervention strategies: early post-operative prophylactic therapy (systematically or based on the patient's risk of recurrence) or starting therapy after confirming endoscopic POR 6-12 months after surgery (endoscopy-driven prophylactic therapy). The risk of overtreatment lies in exposing patients to undesired adverse events, along with the costs associated with medications. Conversely, undertreatment may lead to missed opportunities to prevent bowel damage and the necessity for additional surgery. This article aims to perform a comprehensive review regarding the optimal strategy to reduce the risk of POR in CD patients and the current therapeutic options.

Histology of IBD and related colitides in the elderly

Inflammatory bowel disease (IBD) are chronic relapsing diseases, affecting both children and adults with a life-long duration. An increased co-morbidity gives raise to fragility in the elderly. In this regard it should consider that several non-IBD colitides may mimic both ulcerative colitis and Crohn's disease. Moreover, chronic diseases represent a clinical challenge, mostly about treatment effectiveness. Finally, it is worth noting that patients with long-standing diseases - and elderly patients among them - have an increased malignancy risk when compared to general (non-IBD) population. Our paper aims to review the three main histological topics that play a role in the clinical management of IBD in the elderly, namely differential diagnosis, mucosal healing and IBD-associated dysplasia.

Role of ICAM-1 in the Adhesion of T Cells to Enteric Glia: Perspectives in the Formation of Plexitis in Crohn's Disease

BACKGROUND & AIMS

The presence of myenteric plexitis in the proximal resection margins is a predictive factor of early postoperative recurrence in Crohn's disease. To decipher the mechanisms leading to their formation, T-cell interactions with enteric neural cells were studied in vitro and in vivo.

METHODS

T cells close to myenteric neural cells were retrospectively quantified in ileocolonic resections from 9 control subjects with cancer and 20 patients with Crohn's disease. The mechanisms involved in T-cell adhesion were then investigated in co-cultures of T lymphocytes with enteric glial cells (glia). Finally, the implication of adhesion molecules in the development of plexitis and colitis was studied in vitro but also in vivo in Winnie mice.

RESULTS

The mean number of T cells close to glia, but not neurons, was significantly higher in the myenteric ganglia of relapsing patients with Crohn's disease (2.42 ± 0.5) as compared with controls (0.36 ± 0.08, P = .0007). Co-culture experiments showed that exposure to proinflammatory cytokines enhanced T-cell adhesion to glia and increased intercellular adhesion molecule-1 (ICAM-1) expression in glia. We next demonstrated that T-cell adhesion to glia was inhibited by an anti-ICAM-1 antibody. Finally, using the Winnie mouse model of colitis, we showed that the blockage of ICAM-1/lymphocyte function-associated antigen-1 (LFA-1) with lifitegrast reduced colitis severity and decreased T-cell infiltration in the myenteric plexus.

CONCLUSIONS

Our present work argues for a role of glia-T-cell interaction in the development of myenteric plexitis through the adhesion molecules ICAM-1/LFA-1 and suggests that deciphering the functional consequences of glia-T-cell interaction is important to understand the mechanisms implicated in the development and recurrence of Crohn's disease.

Macroscopic pathology and all that: a personal view

I hope that this treatise adds to the excellent reviews by Varma and colleagues, emphasising the importance of accurate macroscopic assessment and report provision. I have especially highlighted the importance of not divorcing the clinical data and the macroscopic analysis from the microscopic assessment as all are required to provide an accurate and cogent overall composition. The review has also identified areas where the evolution of pathological practice has gone a little awry and requires to be modified and/or justified with evidence base. There is also an emphasis on block economy, as there is no doubt that considerable savings can be made if more attention is paid to more judicious block selection. It is also commended that subspecialties other than gastrointestinal pathology introduce reporting quality standards, like lymph node harvest numbers and other important prognostic and management indicators, to improve the quality of macroscopic pathology worldwide to the benefit of our service users and their patients.

Depletion of muscularis macrophages ameliorates inflammation-driven dysmotility in murine colitis model

Previously, the presence of a blood-myenteric plexus barrier and its disruption was reported in experimentally induced colitis via a macrophage-dependent process. The aim of this study is to reveal how myenteric barrier disruption and subsequent neuronal injury affects gut motility in vivo in a murine colitis model. We induced colitis with dextran sulfate sodium (DSS), with the co-administration of liposome-encapsulated clodronate (L-clodronate) to simultaneously deplete blood monocytes contributing to macrophage infiltration in the inflamed muscularis of experimental mice. DSS-treated animals receiving concurrent L-clodronate injection showed significantly decreased blood monocyte numbers and colon muscularis macrophage (MM) density compared to DSS-treated control (DSS-vehicle). DSS-clodronate-treated mice exhibited significantly slower whole gut transit time than DSS-vehicle-treated animals and comparable to that of controls. Experiments with oral gavage-fed Evans-blue dye showed similar whole gut transit times in DSS-clodronate-treated mice as in control animals. Furthermore, qPCR-analysis and immunofluorescence on colon muscularis samples revealed that factors associated with neuroinflammation and neurodegeneration, including Bax1, Hdac4, IL-18, Casp8 and Hif1a are overexpressed after DSS-treatment, but not in the case of concurrent L-clodronate administration. Our findings highlight that MM-infiltration in the muscularis layer is responsible for colitis-associated dysmotility and enteric neuronal dysfunction along with the release of mediators associated with neurodegeneration in a murine experimental model.

Positive margins and plexitis increase the risk of recurrence after ileocecal resection: A systematic review and meta-analysis

INTRODUCTION

There is debate over the impact of residual microscopic disease after ileocecal resection in Crohn's disease (CD) to predict recurrence. We conducted a meta-analysis to evaluate the impact of positive histological margins and plexitis after ileocecal resection on the risk of postoperative recurrence.

METHODS

Using a systematic search, we identified. 30 studies evaluating the impact of inflammatory margins on CD recurrence. The primary outcome was the postoperative clinical recurrence and secondary outcomes were surgical, and endoscopic recurrence. We performed random-effects meta-analysis and estimated odds ratio (OR) and 95% CIs.

RESULTS

Thirty studies were analyzed, seven focused on myenteric plexitis, six on submucosal plexitis and twenty-three on positive margins. Inflammatory margins were associated with a higher rate of clinical and surgical recurrences: respectively 14 studies - OR 2.38; 95% CI, 1.54 - 3.68- I2 = 68.2%, Q test-p = 0.0003 and 8 studies - OR, 1.52; 95% CI, 1.07-2.16 - I2 =0%; Q test-p = 0.43. The presence of myenteric plexitis was associated with a higher rate of clinical recurrence (4 studies- OR, 1.60; 95%CI, 1.12-2.29; I2= 0%, Q-test-p = 0.61), and of endoscopic recurrence (4 studies - OR, 4.25; 95%CI; 2.06-8.76; I2= 0%, Q test-p = 0.97). Submucosal plexitis was not associated with an increased risk of endoscopic recurrence (4 studies - OR, 0.94; 95%CI; 0.58-1.52; I2= 0%, Q test-p = 0.79).

CONCLUSION

Inflammatory margins and/or plexitis were associated with postoperative recurrence after ileocecal resection for CD. These elements should be taken into account in future algorithm for prevention of postoperative recurrence.

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.

Stemming the tide with ileocecal Crohn's disease: when is pharmacotherapy enough?

INTRODUCTION

Crohn's disease (CD) mostly affects the terminal ileum and ileocecal region and up to 80% of patients end up requiring surgery. Previously reserved for complicated or refractory forms, surgery is now considered as an alternative to medical treatment in localized ileocecal disease.

AREAS COVERED

This review examines factors associated with response to medical treatment and those associated with the need for surgery in ileocecal CD to identify the patients' profile for whom pharmacotherapy might be enough. Factors associated with the recurrence and the postoperative complications are also reviewed to help the clinician identify patients for whom medical therapy might be preferred.

EXPERT’S OPINION

LIR!C study long-term follow-up data show that 38% of infliximab-treated patients were still treated with infliximab at the end of their follow-up, while 14% had switched to another biologic or had received immunomodulator or corticosteroid and 48% had CD-related surgery. Only the combination with an immunomodulator was associated with a greater likelihood of continuing infliximab. Patients with ileocecal CD for whom pharmacotherapy might be sufficient are probably those with no risk factors for CD-related surgery.In addition, patients with high risk of recurrence or of post-operative complications may benefit more from medical treatment than from surgery.

Crohn’s disease: Why the ileum?

Crohn’s disease (CD) is an inflammatory bowel disease characterized by immune-mediated flares affecting any region of the intestine alternating with remission periods. In CD, the ileum is frequently affected and about one third of patients presents with a pure ileal type. Moreover, the ileal type of CD presents epidemiological specificities like a younger age at onset and often a strong link with smoking and genetic susceptibility genes. Most of these genes are associated with Paneth cell dysfunction, a cell type found in the intestinal crypts of the ileum. Besides, a Western-type diet is associated in epidemiological studies with CD onset and increasing evidence shows that diet can modulate the composition of bile acids and gut microbiota, which in turn modulates the susceptibility of the ileum to inflammation. Thus, the interplay between environmental factors and the histological and anatomical features of the ileum is thought to explain the specific transcriptome profile observed in CD ileitis. Indeed, both immune response and cellular healing processes harbour differences between ileal and non-ileal CD. Taken together, these findings advocate for a dedicated therapeutic approach to managing ileal CD. Currently, interventional pharmacological studies have failed to clearly demonstrate distinct response profiles according to disease site. However, the high rate of stricturing disease in ileal CD requires the identification of new therapeutic targets to significantly change the natural history of this debilitating disease.

Prophylactic Treatment with Vedolizumab in the Prevention of Postoperative Recurrence (POR) in High-Risk Crohn's Patients

About 50% of Crohn's Disease (CD) patients undergo an intestinal resection during their lifetime. Although the patients experience a fairly long period of well-being after the intestinal resection, they presented a postoperative recurrence (POR) in 40% of cases within 5 years. In this case series, we aimed to evaluate the incidence of POR in CD patients with high risk for early POR, prophylactically treated with Vedolizumab. All consecutive CD patients (followed from 2017 to 2020) who underwent ileocolonic resection after the loss of response at anti-Tumor Necrosis Factor α (anti-TNFα) and with one or more risk factors for early POR were included. POR was defined as a Rutgeerts score (Ri) > 1 at the colonoscopic evaluation. All the included patients underwent a Magnetic resonance enterography (MRE) at least one year after the surgical resection. Six patients (4 Female; 2 Males) were included. At the first endoscopic evaluation, all patients were in endoscopic remission (5 patients Ri 0; 1 patient Ri 1). No stenosis nor other intestinal wall changes or complications were observed at MRE. Five patients underwent colonoscopy over two years of follow-up (median: 32 months; range 25-33). The Ri score was 0 in four patients, while the fifth patient showed severe endoscopic relapse. The same patient presented a clinical relapse (Harvey-Bradshaw index = 10) with a flare of disease in the colonic mucosa. These data suggest that early post-operative treatment with Vedolizumab could be a valuable strategy to be submitted to a prospective controlled trial for preventing POR.

Precision medicine and drug optimization in adult inflammatory bowel disease patients

Inflammatory bowel diseases (IBD) encompass two main entities including ulcerative colitis and Crohn's disease. Although having a common global pathophysiological mechanism, IBD patients are characterized by a significant interindividual heterogeneity and may differ by their disease type, disease locations, disease behaviours, disease manifestations, disease course as well as treatment needs. Indeed, although the therapeutic armamentarium for these diseases has expanded rapidly in recent years, a proportion of patients remains with a suboptimal response to medical treatment due to primary non-response, secondary loss of response or intolerance to currently available drugs. Identifying, prior to treatment initiation, which patients are likely to respond to a specific drug would improve the disease management, avoid unnecessary side effects and reduce the healthcare expenses. Precision medicine classifies individuals into subpopulations according to clinical and molecular characteristics with the objective to tailor preventative and therapeutic interventions to the characteristics of each patient. Interventions would thus be performed only on those who will benefit, sparing side effects and expense for those who will not. This review aims to summarize clinical factors, biomarkers (genetic, transcriptomic, proteomic, metabolic, radiomic or from the microbiota) and tools that could predict disease progression to guide towards a step-up or top-down strategy. Predictive factors of response or non-response to treatment will then be reviewed, followed by a discussion about the optimal dose of drug required for patients. The time at which these treatments should be administered (or rather can be stopped in case of a deep remission or in the aftermath of a surgery) will also be addressed. IBD remain biologically complex, with multifactorial etiopathology, clinical heterogeneity as well as temporal and therapeutic variabilities, which makes precision medicine especially challenging in this area. Although applied for many years in oncology, it remains an unmet medical need in IBD.

Post-operative prevention and monitoring of Crohn's disease recurrence

Crohn's disease (CD) and ulcerative colitis (UC) are relapsing and remitting chronic inflammatory diseases of the gastrointestinal tract. Although surgery for UC can provide a cure, surgery for CD is rarely curative. In the past few decades, research has identified risk factors for postsurgical CD recurrence, enabling patient risk stratification to guide monitoring and prophylactic treatment to prevent CD recurrence. A MEDLINE literature review identified articles regarding post-operative monitoring of CD recurrence after resection surgery. In this review, we discuss the evidence on risk factors for post-operative CD recurrence as well as suggestions on post-operative management.

Benefit of risk-stratified prophylactic treatment on clinical outcome in post-operative Crohn's disease

BACKGROUND AND AIMS

While immediate post-operative treatment has shown effectiveness in reducing endoscopic post-operative recurrence (POR), evidence regarding the clinical benefit is limited. We compared rates of clinical POR in Crohn's disease (CD) patients receiving immediate prophylactic treatment with patients receiving endoscopy-driven treatment.

METHODS

We retrospectively collected data from 376 consecutive CD patients that underwent an ileocecal resection with anastomosis between 2007 and 2018 with at least 3 years of follow-up at 3 sites. Subsequently, high- and low-risk patients categorized by established guidelines who underwent endoscopy within 12 months postoperatively were grouped according to a prophylactic- or endoscopy-driven approach and compared for incidence and time till endoscopic- and clinical POR.

RESULTS

Prophylactic treatment reduced rates of- and time till endoscopic POR within 1 year in high-risk (HR 0.48, 95% CI 0.27-0.86, p=0.04, NNT=5) but not low-risk (HR 0.90, 95%CI 0.32-2.56, p=0.85) patients. Conversely, no significant differences in clinical POR within 3 years between prophylactic- and endoscopy-driven low-risk (HR 1.17, 95%CI 0.41-3.29, p=0.75) and high-risk patients were observed (HR 1.06, 95%CI 0.63-1.79, p=0.82, NNT=22). However, a large numerical albeit not statistical significant difference in 3 year clinical POR (28.6% vs. 62.5%, p=0.11) in a subset of high-risk patients with ≥3 or more ECCO-defined risk factors was observed, indicating a cumulative effect of having multiple risk factors.

CONCLUSION

Our observations favor step-up treatment guided by early endoscopic evaluation with prophylactic treatment reserved for carefully selected high-risk patients in order to avoid potential overtreatment of a significant number of patients.

Specific Neuropeptide Expression in Crohn's Disease Ileocolonic Resection Specimens Is Not Associated with Plexitis at the Ileal Margin or Postoperative Recurrence

BACKGROUND

Myenteric plexitis is considered a risk factor for postoperative recurrence (POR) in Crohn's disease (CD). The primary purpose of this study was to evaluate the association between neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and substance P (SP) expression and plexitis at the proximal resection margin. The secondary aim was to identify risk factors for POR.

METHODS

A retrospective, single-center study on CD patients who underwent ileocolonic resection (ICR) between January 2010 and December 2016 was conducted. The presence and severity of plexitis were evaluated by hematoxylin and eosin stain. Mast cells were highlighted by Giemsa stain. Immunohistochemistry was used to identify T lymphocytes and NPY-, VIP-, and SP-ergic neurons. Neuropeptide expression was quantified using image analysis.

RESULTS

Seventy-nine patients were included. No association was detected between NPY, VIP, and SP expression and plexitis. Similarly, the number of involved inflammatory cells, T lymphocytes or mast cells was not correlated with neuropeptide expression. Smoking (hazard ratio [HR] 4.07; 95% confidence interval [CI] 2.08-7.94; p < 0.001), moderate (HR 3.68; 95%CI 1.06-12.73; p = 0.040), and severe myenteric plexitis (HR 7.36; 95%CI 1.12-48.30; p = 0.037) were independent risk factors for endoscopic POR, whereas smoking (HR 2.78; 95%CI 1.01-7.67; p = 0.049), severe myenteric plexitis (HR 20.03; 95%CI 1.09-368.28; p = 0.044), and involved ileal margin (HR 3.45; 95%CI 1.33-8.96; p = 0.011) for clinical POR.

CONCLUSIONS

Smoking, moderate or severe myenteric plexitis, and involved ileal margin negatively affect POR in CD patients undergoing ICR. Submucosal and myenteric plexitis at the proximal resection margin is not related to the expression of specific neuropeptides.

Targeting Enteric Neurons and Plexitis for the Management of Inflammatory Bowel Disease

Ulcerative colitis (UC) and Crohn's disease (CD) are pathological conditions with an unknown aetiology that are characterised by severe inflammation of the intestinal tract and collectively referred to as inflammatory bowel disease (IBD). Current treatments are mostly ineffective due to their limited efficacy or toxicity, necessitating surgical resection of the affected bowel. The management of IBD is hindered by a lack of prognostic markers for clinical inflammatory relapse. Intestinal inflammation associates with the infiltration of immune cells (leukocytes) into, or surrounding the neuronal ganglia of the enteric nervous system (ENS) termed plexitis or ganglionitis. Histological observation of plexitis in unaffected intestinal regions is emerging as a vital predictive marker for IBD relapses. Plexitis associates with alterations to the structure, cellular composition, molecular expression and electrophysiological function of enteric neurons. Moreover, plexitis often occurs before the onset of gross clinical inflammation, which may indicate that plexitis can contribute to the progression of intestinal inflammation. In this review, the bilateral relationships between the ENS and inflammation are discussed. These include the effects and mechanisms of inflammation-induced enteric neuronal loss and plasticity. Additionally, the role of enteric neurons in preventing antigenic/pathogenic insult and immunomodulation is explored. While all current treatments target the inflammatory pathology of IBD, interventions that protect the ENS may offer an alternative avenue for therapeutic intervention.

Positive histologic margins is a risk factor of recurrence after ileocaecal resection in Crohn's disease

INTRODUCTION

Surgical resection is not curative in Crohn's disease (CD) and, recurrence after surgery is a common situation. The identification of patients at high risk of recurrence remains disappointing in clinical practice.

OBJECTIVE

To evaluate the impact of residual microscopic disease on margins on the risk of recurrence after ileocaecal resection in CD.

PATIENTS AND METHODS

All patients who underwent ileocaecal resection between January 1992 and December 2016 were prospectively identified. Demographic data, clinical, surgical and histological variables were retrospectively collected. Positive histologic margin was assessed prospectively and defined by the presence of acute inflammatory lesions on margins: erosion, ulceration, chorion infiltration by neutrophils, cryptic abscesses or cryptitis.

RESULTS

One hundred twenty five patients were included, with a median follow-up of 8 years (Interquartile Range (IQR), 4.3-15.2). Half (49.6%, n = 62) were women, and the median age at surgery was 33 years (IQR, 24-42). Fifty-six (44.8%) had positive inflammatory margins. Five years after surgery, respectively 29 (51%) and 23 (34%) patients with positive and negative margins had clinical recurrence (p = 0.034). At the end of the follow-up, respectively 60% (n = 34) and 47% (n = 33) patients had clinical recurrence (p = 0.07). CD-related hospitalizations were observed in respectively 37.5% (n = 21) and 18.8% (n = 13) with positive and negative margins (p = 0.02). Fourteen patients (25%) with positive intestinal margins had surgical recurrence at the end of the follow-up compared to 5 patients (7%) with negative margins (p = 0.04). Multivariate analysis confirmed that positive intestinal margin was independently associated with surgical recurrence (OR, 4.7 (CI95%, 1.4-15.3), p = 0.01).

CONCLUSION

Positive histologic margin was associated with an increased risk of clinical and surgical recurrence after ileocaecal resection for Crohn's disease.

Evidence of a Myenteric Plexus Barrier and Its Macrophage-Dependent Degradation During Murine Colitis: Implications in Enteric Neuroinflammation

BACKGROUND & AIMS

Neuroinflammation in the gut is associated with many gastrointestinal (GI) diseases, including inflammatory bowel disease. In the brain, neuroinflammatory conditions are associated with blood-brain barrier (BBB) disruption and subsequent neuronal injury. We sought to determine whether the enteric nervous system is similarly protected by a physical barrier and whether that barrier is disrupted in colitis.

METHODS

Confocal and electron microscopy were used to characterize myenteric plexus structure, and FITC-dextran assays were used to assess for presence of a barrier. Colitis was induced with dextran sulfate sodium, with co-administration of liposome-encapsulated clodronate to deplete macrophages.

RESULTS

We identified a blood-myenteric barrier (BMB) consisting of extracellular matrix proteins (agrin and collagen-4) and glial end-feet, reminiscent of the BBB, surrounded by a collagen-rich periganglionic space. The BMB is impermeable to the passive movement of 4 kDa FITC-dextran particles. A population of macrophages is present within enteric ganglia (intraganglionic macrophages [IGMs]) and exhibits a distinct morphology from muscularis macrophages, with extensive cytoplasmic vacuolization and mitochondrial swelling but without signs of apoptosis. IGMs can penetrate the BMB in physiological conditions and establish direct contact with neurons and glia. Dextran sulfate sodium-induced colitis leads to BMB disruption, loss of its barrier integrity, and increased numbers of IGMs in a macrophage-dependent process.

CONCLUSIONS

In intestinal inflammation, macrophage-mediated degradation of the BMB disrupts its physiological barrier function, eliminates the separation of the intra- and extra-ganglionic compartments, and allows inflammatory stimuli to access the myenteric plexus. This suggests a potential mechanism for the onset of neuroinflammation in colitis and other GI pathologies with acquired enteric neuronal dysfunction.

ECCO Topical Review Optimising Reporting in Surgery, Endoscopy, and Histopathology

BACKGROUND AND AIMS

Diagnosis and management of inflammatory bowel diseases [IBD] requires a lifelong multidisciplinary approach. The quality of medical reporting is crucial in this context. The present topical review addresses the need for optimised reporting in endoscopy, surgery, and histopathology.

METHODS

A consensus expert panel consisting of gastroenterologists, surgeons, and pathologists, convened by the European Crohn's and Colitis Organisation, performed a systematic literature review. The following topics were covered: in endoscopy: [i] general IBD endoscopy; [ii] disease activity and surveillance; [iii] endoscopy treatment in IBD; in surgery: [iv] medical history with surgical relevance, surgical indication, and strategy; [v] operative approach; [vi] intraoperative disease description; [vii] operative steps; in pathology: [viii] macroscopic assessment and interpretation of resection specimens; [ix] IBD histology, including biopsies, surgical resections, and neoplasia; [x] IBD histology conclusion and report. Statements were developed using a Delphi methodology incorporating two consecutive rounds. Current practice positions were set when ≥ 80% of participants agreed on a recommendation.

RESULTS

Thirty practice positions established a standard terminology for optimal reporting in endoscopy, surgery, and histopathology. Assessment of disease activity, surveillance recommendations, advice to surgeons for operative indication and strategies, including margins and extent of resection, and diagnostic criteria of IBD, as well as guidance for the interpretation of dysplasia and cancer, were handled. A standardised report including a core set of items to include in each specialty report, was defined.

CONCLUSIONS

Interdisciplinary high-quality care requires thorough and standardised reporting across specialties. This topical review offers an actionable framework and practice recommendations to optimise reporting in endoscopy, surgery, and histopathology.

Ileal or Colonic Histologic Activity Is Not Associated With Clinical Relapse in Patients With Crohn's Disease in Endoscopic Remission

BACKGROUND & AIMS

Goals of treatment for Crohn's disease (CD) are clinical and endoscopic remission. It is not clear whether histologic markers of healing associate with endoscopic remission in patients with CD.

METHODS

We identified patients with CD from a single institutional registry, and collected data from 129 patients (46.5% female; mean age 25 y; mean CD duration 14.5 y) who underwent colonoscopy evaluation and had simple endoscopic scores for CD below 3 (the definition of endoscopic remission). Histologic signs of CD activity were graded in 192 biopsies (90 ileum and 102 colon), and disease was classified as active (presence of crypt destruction, neutrophils, erosions or ulcerations), quiescent (presence of architectural distortion and chronic inflammatory infiltrate), or normal histology (none of these). The primary outcome was clinical relapse within 2 y (dose escalation, change in therapy, need for systemic steroids, or CD-related hospitalization or surgery). We performed multivariable regression adjusting for relevant confounders to examine the independent predictive value of histologic activity.

RESULTS

Within 2 y of endoscopic evaluation, 42 patients (32.6%) had a clinical relapse. There were no significant differences in proportions of patients with active ileal CD (23.8%), quiescent CD (28.6%), or normal histology (37%) between those who relapsed and those remaining in remission (P = .43). There were no significant differences in proportions of relapses among patients with active colonic disease (38.1%), quiescent disease (35.0%), or normal histology (27.9%, P = .73). A linear regression analysis found no association between histologic features of active disease in ileal histology biopsies and symptom scores (Harvey Bradshaw index and simple inflammatory bowel disease questionnaire scores).

CONCLUSIONS

In an analysis of biopsies from patients with CD who had achieved clinical and endoscopic remission, histologic remission was not associated with clinical relapse within 2 years.

Risk factors for symptomatic anastomotic postoperative recurrence following ileo-colic resection in Crohn's disease

AIM

Crohn's disease is a chronic inflammatory bowel disease characterized by alternating periods of exacerbation and remission. Surgical resection is not curative and postoperative recurrence (POR) remains a challenge in these patients. The aim of this study was to identify clinical variables that influence the risk of symptomatic anastomotic POR in patients with ileo-colonic Crohn's disease.

METHOD

A retrospective study of Crohn's disease patients who had undergone ileo-colic resection between January 2014 and December 2018 was performed. For each patient, data including demographic information, Crohn's disease clinical setting, preoperative radiological data, operative and histological data, pre- and postoperative medication history and postoperative clinical course, including recurrence of disease, were extracted. Symptomatic anastomotic POR was defined as symptoms of Crohn's disease in the presence of confirmed anastomotic POR (endoscopic and/or radiological POR).

RESULTS

For the study period, 104 patients were eligible and included for analysis. The cumulative probability of symptomatic anastomotic POR was 14%, 30%, 42%, 50% and 50% at 1, 2, 3, 4 and 5 years, respectively. Two clinical variables on multivariate analysis were associated with increased risk of symptomatic anastomotic POR, namely age <17 years at diagnosis [hazard ratio (HR) 2.17, p = 0.019] and gastrointestinal involvement (extent) >30 cm (HR 1.85, p = 0.048).

CONCLUSION

This study describes the natural history of POR after ileo-colic resection for Crohn's disease, as defined by endoscopic, radiological and clinical outcomes. Age <17 years at diagnosis and gastrointestinal involvement (extent) >30 cm were independent risk factors for symptomatic anastomotic POR.

Conservative management of spontaneous intra-abdominal abscess in Crohn's disease: Outcome and prognostic factors

OBJECTIVE

To compare the outcomes of different treatments for spontaneous intra-abdominal abscesses (IAA) in active Crohn's disease (CD).

METHODS

A retrospective analysis of patients with CD between January 2007 and December 2018 was performed in two Belgian inflammatory bowel disease centers. Successful conservative management was defined as complete resolution of abscesses without the need for bowel resection. The primary outcome was suboptimal evolution, defined as a composite outcome of recurrence of abscess, postoperative complications or the need for a non-elective resection.

RESULTS

Forty CD patients presenting with 43 independent episodes of spontaneous IAA development were included. One underwent immediate bowel resection. In all other 42 cases a conservative approach was taken, which led to a complete abscess resolution rate of 28.6% (12/42). The remaining abscesses required bowel resection. Anti-tumor necrosis factor (TNF) agent use was associated with successful conservative management (odds ratio [OR] 13.36, 95% confidence interval [CI] 11.19-15.52, P = 0.006), while the opposite trend was found for corticosteroids (OR 0.14, 95% CI 0.02-1.26, P = 0.055). There was a trend towards suboptimal evolution in case of previous bowel resection (OR 4.77, 95% CI 0.77-29.66, P = 0.094) or in patients aged above 50 years (OR 5.17, 95% CI 0.86-30.91, P = 0.072).

CONCLUSIONS

Bowel resection appears to be inevitable in most CD patients presenting with IAA. An attempt at conservative treatment may be particularly successful with anti-TNF agents in younger patients who have not undergone previous bowel resection. Large-scale prospective studies are needed to confirm these findings.

Active Margins, Plexitis, and Granulomas Increase Postoperative Crohn's Recurrence: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Rates of postoperative Crohn's disease recurrence remain high, although the ability to predict this risk of recurrence remains limited. As such, we aimed to determine the association of histologic features at the time of resection with postoperative recurrence.

METHODS

Electronic databases were searched through February 2020 for studies that reported risk of clinical, endoscopic, or surgical postoperative recurrence in patients with positive resection margins, plexitis, or granulomas in the index specimen. Pooled risk ratios (RRs) with 95% CIs were calculated for this risk in patients with and without these histologic features.

RESULTS

Twenty-one studies (2481 patients) assessed positive resection margins, 10 studies (808 patients) assessed plexitis, and 19 studies (1777 patients) assessed granulomas. Positive resection margins increased the risk of clinical (RR, 1.26; 95% CI, 1.06-1.49; I² = 41%) and surgical (RR, 1.87; 95% CI, 1.14-3.08; I² = 71%) recurrence, with a trend toward endoscopic recurrence (RR, 1.56; 95% CI, 0.79-3.05; I² = 85%). Granulomas increased the risk of clinical (RR, 1.31; 95% CI, 1.05-1.64; I² = 36%) and endoscopic (RR, 1.37; 95% CI, 1.00-1.87; I² = 49%) recurrence, with a trend toward surgical recurrence (RR, 1.58; 95% CI, 0.89-2.80; I² = 75%). Plexitis increased the risk of endoscopic recurrence (RR, 1.31; 95% CI, 1.00-1.72; I² = 20%), with a trend toward clinical recurrence (RR, 1.34; 95% CI, 0.95-1.91; I² = 46%).

CONCLUSIONS

Positive resection margins, granulomas, and plexitis are predictive of postoperative Crohn's disease recurrence and should be recorded at the time of index resection.

Histopathology of IBD Colitis. A practical approach from the pathologists of the Italian Group for the study of the gastrointestinal tract (GIPAD)

Inflammatory bowel diseases (IBDs) are lifelong disorders in which an interaction between genetic and environmental factors is involved. IBDs include two entities: Crohn's disease (CD) and ulcerative colitis (UC); these can be adequately diagnosed and distinguished with a correct methodological approach based on communicating exhaustive clinical, endoscopic and laboratory information to the pathologist and performing adequate bioptic sampling and precise morphological signs including crypt architecture, distribution of inflammation and granulomas, when present. IBD needs to be distinguished from non-IBD colitis, mostly at its onset. Moreover, IBDs are associated with an increased risk of developing colorectal adenocarcinoma. In daily pathological practice, correct diagnosis of IBD and its subclassification as well as a correct detection of dysplasia is imperative to establish the best therapeutic approach.

T cells show preferential adhesion to enteric neural cells in culture and are close to neural cells in the myenteric ganglia of Crohn's patients

Plexitis in the proximal margin of intestinal resections are associated with post-operative recurrence of Crohn's disease. To understand their formation, in vitro analyzes were performed. T cells adhered preferentially to neuron and glial cells in mixed primary cultures of enteric nervous system and T cell activation increased their adhesion capacity. Higher number of T lymphocytes in close proximity to enteric glial cells was also observed in the myenteric ganglia of Crohn's patients as compared to control. These data show that close proximity between lymphocytes and enteric neural cells exists and may contribute to the formation of plexitis.

Inflammatory bowel disease position statement of the Italian Society of Colorectal Surgery (SICCR): Crohn's disease

The Italian Society of Colorectal Surgery (SICCR) promoted the project reported here, which consists of a position statement of Italian colorectal surgeons to address the surgical aspects of Crohn's disease management. Members of the society were invited to express their opinions on several items proposed by the writing committee, based on evidence available in the literature. The results are presented, focusing on relevant points. The present paper is not an alternative to available guidelines; rather, it offers a snapshot of the attitudes of SICCR surgeons about the surgical treatment of Crohn's disease. The committee was able to identify some points of major disagreement and suggested strategies to improve quality of available data and acceptance of guidelines.

Histopathology of inflammatory bowel disease - Position statement of the Pathologists of the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) and Italian Group of Gastrointestinal Pathologists (GIPAD-SIAPEC)

Diagnosis of the inflammatory bowel diseases ulcerative colitis (UC) and Crohn's disease (CD) relies mainly on the histopathological examination of endoscopic biopsies of the gastrointestinal tract. To facilitate the accurate diagnosis of these two conditions, this paper addresses key issues on the: (A) gastrointestinal biopsy procedure, (B) histomorphological characteristics of UC and CD, and (C) diagnosis of dysplasia. The 13 statements presented here represent the consensus of two groups of Italian pathologists (IG-IBD and GIPAD).

Association Between Microscopic Lesions at Ileal Resection Margin and Recurrence After Surgery in Patients With Crohn's Disease

BACKGROUND AND AIMS

Different types of histologic lesions at the ileal margin, detected by histology, have been associated with increased rates of recurrence after ileocaecal surgery in patients with Crohn's disease (CD). We aimed to characterize histologic features of the ileal margin and to evaluate their association with disease recurrence.

METHODS

We collected histologic data from 211 patients with ileal or ileocolonic CD who underwent ileocolonic resections at hospitals in France from September 2010 through December 2016. Ileal margins were analyzed. Early endoscopic recurrence was defined by a Rutgeerts score of i2 or more, 6 months after surgery. We also collected data from 10 adults with healthy ileum who underwent ileocecal resection for colonic tumors (controls). Clinical relapse was defined by CD-related symptoms confirmed by imaging, endoscopy, therapy intensification, CD-related complication, or subsequent surgery.

RESULTS

Six months after surgery, 49% of patients had endoscopic recurrence; 5 years after surgery, 57% of patients had clinical relapse. Ileal margins were macroscopically affected in 20.9% of patients. CD transmural lesions at the margin (defined by mucosal ulceration or cryptitis, submucosal fibrosis and lymphoplasmacytic infiltrate of the subserosa) were observed in 13.6% of patients. Endoscopic recurrence was observed in 75% of patients with CD transmural lesions vs 46% of patients without (P =.005). In multivariate analysis, CD transmural lesions at the margin were independently associated with early endoscopic recurrence (OR, 3.83; 95% CI, 1.47-11.05; P =.008) and clinical recurrence (OR 2.04; 95% CI, 1.09-3.99; P =.026).

CONCLUSION

In patients with CD, transmural lesions at the ileal margin were associated with an increased risk of post-operative recurrence. Histologic features of the ileal margin should be included in making decisions about post-operative therapy.

Meta-analysis of Histological Margin Positivity in the Prediction of Recurrence After Crohn's Resection

BACKGROUND

Despite significant advances in the medical management of Crohn's disease, many patients will require intestinal resection during their lifetime. It is disappointing that many will also develop disease recurrence.

OBJECTIVES

The current study utilizes meta-analytical techniques to determine the effect of positive histological margins at the time of index resection on disease recurrence.

DATA SOURCES

Embase, Medline, PubMed, PubMed Central, and Cochrane databases were searched using a Boolean search algorithm for articles published up to August 2017.

STUDY SELECTION

Meta-analysis was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

MAIN OUTCOME MEASURES

Databases were searched for studies reporting the outcomes for patients with Crohn's disease undergoing primary resection that correlated resection margin status with disease recurrence. Results were reported as pooled ORs with 95% CI.

RESULTS

A total of 176 citations were reviewed; 18 studies comprising 1833 patients were ultimately included in the analysis, with a mean rate of histopathological margin positivity of 41.7 ± 17.4% and a pooled mean follow-up of 69 ± 39 months. Histopathological margin positivity was associated with a higher rate of overall recurrence (OR, 1.7; 95% CI, 1.3-2.1; p < 0.001), clinical recurrence (OR, 1.7; 95% CI, 1.0-2.8; p = 0.04), and anastomotic recurrence (OR, 1.6; 95% CI, 1.0-2.3; p = 0.03). In studies reporting plexitis specifically at the resection margin, there was an increase in recurrence (OR, 2.3; 95% CI, 1.1-4.9; p = 0.02).

LIMITATIONS

The definitions of histological margin positivity and postoperative recurrence vary between the studies and follow-up durations vary.

CONCLUSIONS

The presence of involved histological margins at the time of index resection in Crohn's disease is associated with recurrence, and plexitis shows promise as a marker of more aggressive disease. Further studies with homogeneity of histopathological and recurrence reporting are required.

The Role of Histology in Determining Disease Activity, Treatment, and Prognosis: Are We There yet?

Histologic activity in inflammatory bowel disease is associated with an increased risk of clinical relapse, surgery, hospitalizations, and disease-associated dysplasia independent of clinical or endoscopic activity. Several histologic scoring systems exist to capture disease activity. However, none has been validated to assess prognosis or response to therapy and there is no universally accepted definition of histologic healing or remission. Although histologic healing is not a current recommended target for treatment, it may be a more sensitive marker of disease activity. Future studies are needed to determine standardized definitions of disease activity, healing, and evaluating normalization of histology as clinical trial outcomes.

The Association of Coloproctology of Great Britain and Ireland consensus guidelines in surgery for inflammatory bowel disease

AIM

There is a requirement of an expansive and up to date review of surgical management of inflammatory bowel disease (IBD) that can dovetail with the medical guidelines produced by the British Society of Gastroenterology.

METHODS

Surgeons who are members of the ACPGBI with a recognised interest in IBD were invited to contribute various sections of the guidelines. They were directed to produce a procedure based document using literature searches that were systematic, comprehensible, transparent and reproducible. Levels of evidence were graded. An editorial board was convened to ensure consistency of style, presentation and quality. Each author was asked to provide a set of recommendations which were evidence based and unambiguous. These recommendations were submitted to the whole guideline group and scored. They were then refined and submitted to a second vote. Only those that achieved >80% consensus at level 5 (strongly agree) or level 4 (agree) after 2 votes were included in the guidelines.

RESULTS

All aspects of surgical care for IBD have been included along with 157 recommendations for management.

CONCLUSION

These guidelines provide an up to date and evidence based summary of the current surgical knowledge in the management of IBD and will serve as a useful practical text for clinicians performing this type of surgery.

Predictive value of myenteric and submucosal plexitis for postoperative Crohn's disease recurrence

Objectives: To assess the predictive values of myenteric and submucosal plexitis for postoperative endoscopic recurrence of Crohn's disease (CD). Methods: A retrospective study of CD patients who underwent intestinal resection between 1995 and 2013 in the Department of Surgery 2, Tokyo Women's Medical University was performed. Proximal resection margins were analyzed and plexitis was evaluated by counting the number of inflammatory cells in myenteric and submucosal plexuses. The sizes of the most severely inflamed ganglion (MIG) were measured. Multiple regression analysis was used to identify independent risk factors for postoperative endoscopic recurrence. Results: Of the 51 included patients, 40 patients underwent colonoscopy after surgery. Endoscopic recurrence was observed in 21 patients (52.5%). Mean duration (±standard deviation) from surgery to recurrence was 49.7±34.7 months. Endoscopic recurrence rates at 1, 3, and 5 years were 5.0%, 24.1%, and 45.1%, respectively. Submucosal plexitis and myenteric plexitis were observed in 36 (90.0%) and 37 patients (92.5%), respectively. On multivariate analysis, initial intestinal resection, rate of plexitis <50%, size of the MIG in the myenteric plexus ≥867 μm², and total number of inflammatory cells in the submucosal plexus ≥8 were independent risk factors for postoperative endoscopic recurrence. Conclusions: Pathological findings of proximal resection margins, especially submucosal plexitis and large sizes of myenteric plexus, are predictive of postoperative endoscopic recurrence in CD.

Risk factors for postoperative recurrence of Crohn's disease with emphasis on surgical predictors

Intestinal resection for Crohn’s disease is not curative and postoperative recurrence rates remain high. Early detection of indices associated with recurrence and risk stratification are fundamental for the postoperative management of patients. Early endoscopy at 6-12 months is the “gold standard” procedure, whereas other modalities such as fecal calprotectin and imaging techniques can contribute to the diagnosis of recurrence. The purpose of this review is to summarize current data regarding risk factors correlated with postoperative relapse. Smoking is a well-established, modifiable risk factor. There are sufficient data that correlate penetrating disease, perianal involvement, extensive resections, prior surgery, histological features (plexitis and granulomas), and improper management after resection with high rates for recurrence. The literature provides conflicting data for other possible predictors, such as age, sex, family history of inflammatory bowel disease, location of disease, strictureplasties, blood transfusions, and postoperative complications, necessitating further evidence. On the other hand, surgical factors such as anastomotic configuration, open or laparoscopic approach, and microscopic disease at specimen margins when macroscopic disease is resected, seem not to be related with an increased risk of recurrence. Further recognition of histological features as well as gene-related factors are promising fields for research.

Disease activity and mucosal healing in inflammatory bowel disease: a new role for histopathology?

Histologic evaluation of disease activity in the setting of inflammatory bowel disease is gaining interest within the gastroenterology community. Recent data suggests that histologic measurements of inflammation in ulcerative colitis are more sensitive at detecting disease activity and perform better than endoscopic measurements in predicting clinical outcomes. Histologic measurements are also increasingly used in ulcerative colitis clinical trials to assess response to new therapies. Histologic measurements of disease activity are less well studied in Crohn's disease, but are gaining attention. Current published treatment algorithms in inflammatory bowel disease do not take into consideration histologic activity; however, this may change in the near future. In order for histologic measurements to be included in clinical decision-making, validated, reliable, and responsive histologic scoring systems are needed. In this review, the recent literature on the significance of histologic activity in both ulcerative colitis and Crohn's disease is summarized. Histologic scoring systems are also briefly discussed.

Visceral adiposity predicts post-operative Crohn's disease recurrence

BACKGROUND

Excessive visceral adipose tissue has been associated with poorer outcomes in patients with inflammatory bowel disease.

AIM

To determine whether body composition is associated with outcome in a prospective study of post-operative Crohn's disease patients.

METHODS

The POCER study evaluated management strategies for prevention of post-operative Crohn's disease recurrence; subjects were enrolled after resection of all macroscopic Crohn's disease and were randomised to early endoscopy and possible treatment escalation, or standard care. The primary endpoint was endoscopic recurrence at 18 months. 44 subjects with cross-sectional abdominal imaging were studied, and body composition analysis performed using established techniques to measure visceral adipose tissue area, subcutaneous adipose tissue area, and skeletal muscle area.

RESULTS

The body composition parameter with the greatest variance was visceral adipose tissue. Regardless of treatment, all subjects with visceral adipose tissue/height² >1.5 times the gender-specific mean experienced endoscopic recurrence at 18 months (compared to 47%) [relative risk 2.1, 95% CI 1.5-3.0, P = 0.012]. Waist circumference correlated strongly with visceral adipose tissue area (ρ = 0.840, P < 0.001). Low skeletal muscle was prevalent (41% of patients), but did not predict endoscopic recurrence; however, appendicular skeletal muscle indices correlated inversely with faecal calprotectin (ρ = 0.560, P = 0.046).

CONCLUSIONS

Visceral adiposity is an independent risk factor for endoscopic recurrence of Crohn's disease after surgery. Sarcopenia correlates with inflammatory biomarkers. Measures of visceral adipose tissue may help to stratify risk in post-operative management strategies.

Management of post-operative Crohn's disease in 2017: where do we go from here?

Postoperative recurrence (POR) of Crohn's disease is common after surgical resection. How to best manage POR remains uncertain. Areas covered: In this review, we will first describe the natural course and the best modalities to diagnose this surgical sequela. We will then focus on the potential risk factors for relapse and highlight the main shortcomings in the current study designs and endoscopic and clinical scoring systems, which may partly explain the unexpected outcomes of recent clinical trials. Finally, we will propose a strategy to address the management of POR. Expert commentary: Anti-tumor necrosis factor (Anti-TNF) agents are the most effective therapy to prevent POR in Crohn's disease. Patient risk stratification and active monitoring with scheduled ileocolonoscopy are cornerstones of optimal POR management. Further studies are needed to address areas of uncertainty including timing and duration of therapy and the role of therapeutic drug monitoring in this setting.