Plexitis as a predictive factor of early postoperative clinical recurrence in Crohn's disease

Outcomes and Endpoints of Postoperative Recurrence in Crohn's Disease: Systematic Review and Consensus Conference

BACKGROUND

Outcomes after ileocolonic resection in Crohn's disease [CD] are heterogeneous, and a clear definition of postoperative recurrence remains to be determined. Our Endpoints Working Group of the International Organization for the study of Inflammatory Bowel Disease [IOIBD] aimed to standardise postoperative outcomes, to discuss which endpoints should be used for postoperative clinical trials, and to define those which could be used in trials or registries.

METHODS

Based on a systematic review of the literature, recommendations and statements were drafted and sent to all IOIBD members for a first round of voting. Recommendations and statements were revised based on the voters' comments during a consensus hybrid conference open to all IOIBD members. If no agreement was reached after two rounds of voting, the statement was excluded.

RESULTS

In the systematic review, 3071 manuscripts were screened of which 434 were included. Sixteen recommendations were identified, of which 11 were endorsed. Recommendations and statements include that endoscopy remains the gold standard and should be used as a short-term primary endpoint in both observational cohorts and randomised controlled trials. Clinical symptoms classically used in clinical trials for luminal CD are not reliable in this specific situation. For that reason, longer-term endpoints should be based on the evidence of macroscopic inflammation assessed by imaging techniques, endoscopy, or as reflected by the presence of complications.

CONCLUSIONS

Agencies recommend the use of clinical evaluations, as in the case of luminal CD, and do not recognise primary endpoints based solely on endoscopy. This consensus has led to agreement on the need to define postoperative endoscopy-based and/or imaging-based endpoints.

Enteric Nervous System Alterations in Inflammatory Bowel Disease: Perspectives and Implications

The enteric nervous system (ENS), consisting of neurons and glial cells, is situated along the gastrointestinal (GI) tract's wall and plays a crucial role in coordinating digestive processes. Recent research suggests that the optimal functioning of the GI system relies on intricate connections between the ENS, the intestinal epithelium, the immune system, the intestinal microbiome, and the central nervous system (CNS). Inflammatory bowel disease (IBD) encompasses a group of chronic inflammatory disorders, such as Crohn's disease (CD) and ulcerative colitis (UC), characterized by recurring inflammation and damage to the GI tract. This review explores emerging research in the dynamic field of IBD and sheds light on the potential role of ENS alterations in both the etiology and management of IBD. Specifically, we delve into IBD-induced enteric glial cell (EGC) activation and its implications for persistent enteric gliosis, elucidating how this activation disrupts GI function through alterations in the gut-brain axis (GBA). Additionally, we examine IBD-associated ENS alterations, focusing on EGC senescence and the acquisition of the senescence-associated secretory phenotype (SASP). We highlight the pivotal role of these changes in persistent GI inflammation and the recurrence of IBD. Finally, we discuss potential therapeutic interventions involving senotherapeutic agents, providing insights into potential avenues for managing IBD by targeting ENS-related mechanisms. This approach might represent a potential alternative to managing IBD and advance treatment of this multifaceted 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.

First Mexican Consensus on Crohn's disease

INTRODUCTION

Crohn's disease (CD) is a subtype of chronic and incurable inflammatory bowel disease. It can affect the entire gastrointestinal tract and its etiology is unknown.

OBJECTIVE

The aim of this consensus was to establish the most relevant aspects related to definitions, diagnosis, follow-up, medical treatment, and surgical treatment of Crohn's disease in Mexico.

MATERIAL AND METHODS

Mexican specialists in the areas of gastroenterology and inflammatory bowel disease were summoned. The consensus was divided into five modules, with 69 statements. Applying the Delphi panel method, the pre-meeting questions were sent to the participants, to be edited and weighted. At the face-to-face meeting, all the selected articles were shown, underlining their level of clinical evidence; all the statements were discussed, and a final vote was carried out, determining the percentage of agreement for each statement.

RESULTS

The first Mexican consensus on Crohn's disease was produced, in which recommendations for definitions, classifications, diagnostic aspects, follow-up, medical treatment, and surgical treatment were established.

CONCLUSIONS

Updated recommendations are provided that focus on definitions, classifications, diagnostic criteria, follow-up, and guidelines for conventional medical treatment, biologic therapy, and small molecule treatment, as well as surgical management.

Bone marrow-derived mesenchymal stem cells mitigate chronic colitis and enteric neuropathy via anti-inflammatory and anti-oxidative mechanisms

Current treatments for inflammatory bowel disease (IBD) are often inadequate due to limited efficacy and toxicity, leading to surgical resection in refractory cases. IBD's broad and complex pathogenesis involving the immune system, enteric nervous system, microbiome, and oxidative stress requires more effective therapeutic strategies. In this study, we investigated the therapeutic potential of bone marrow-derived mesenchymal stem cell (BM-MSC) treatments in spontaneous chronic colitis using the Winnie mouse model which closely replicates the presentation and inflammatory profile of ulcerative colitis. The 14-day BM-MSC treatment regimen reduced the severity of colitis, leading to the attenuation of diarrheal symptoms and recovery in body mass. Morphological and histological abnormalities in the colon were also alleviated. Transcriptomic analysis demonstrated that BM-MSC treatment led to alterations in gene expression profiles primarily downregulating genes related to inflammation, including pro-inflammatory cytokines, chemokines and other biomarkers of inflammation. Further evaluation of immune cell populations using immunohistochemistry revealed a reduction in leukocyte infiltration upon BM-MSC treatment. Notably, enteric neuronal gene signatures were the most impacted by BM-MSC treatment, which correlated with the restoration of neuronal density in the myenteric ganglia. Moreover, BM-MSCs exhibited neuroprotective effects against oxidative stress-induced neuronal loss through antioxidant mechanisms, including the reduction of mitochondrial-derived superoxide and attenuation of oxidative stress-induced HMGB1 translocation, potentially relying on MSC-derived SOD1. These findings suggest that BM-MSCs hold promise as a therapeutic intervention to mitigate chronic colitis by exerting anti-inflammatory effects and protecting the enteric nervous system from oxidative stress-induced damage.

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.

Potential roles of enteric glial cells in Crohn's disease: A critical review

Enteric glial cells in the enteric nervous system are critical for the regulation of gastrointestinal homeostasis. Increasing evidence suggests two-way communication between enteric glial cells and both enteric neurons and immune cells. These interactions may be important in the pathogenesis of Crohn's disease (CD), a chronic relapsing disease characterized by a dysregulated immune response. Structural abnormalities in glial cells have been identified in CD. Furthermore, classical inflammatory pathways associated with CD (e.g., the nuclear factor kappa-B pathway) function in enteric glial cells. However, the specific mechanisms by which enteric glial cells contribute to CD have not been summarized in detail. In this review, we describe the possible roles of enteric glial cells in the pathogenesis of CD, including the roles of glia-immune interactions, neuronal modulation, neural plasticity, and barrier integrity. Additionally, the implications for the development of therapeutic strategies for CD based on enteric glial cell-mediated pathogenic processes are discussed.

Schaumann bodies deposited along myenteric plexus of the muscularis propria is a unique histopathological feature of Crohn's disease

AIMS

Schaumann bodies were first identified in sarcoidosis by Dr Schaumann in 1941. They were also detected in 10% of Crohn's disease (CD) cases in a study involving patients with surgically resected CD. However, the characteristics and significance of Schaumann bodies in CD have yet to be fully elucidated. This study aimed to determine the pathological features and diagnostic significance of Schaumann bodies in various bowel diseases.

METHODS

Overall, 278 bowel specimens were collected from patients with CD, intestinal tuberculosis, ulcerative colitis, intestinal schistosomiasis, diverticulosis and idiopathic mesenteric vasculopathy. The frequency, pathology and clinical features of patients with Schaumann bodies were studied.

RESULTS

Schaumann bodies were present exclusively in CD (27.0%, 38 of 141) and were not detected in other intestinal diseases within the series. In CD, Schaumann bodies were deposited along the myenteric plexus of the muscularis propria (84.2%, 32 of 38). These bodies were small (diameter: 60.3±32.7 µm) and exhibited a low density in the intestinal wall (1.1±0.4 per low-power field). The majority were located within the cytoplasm of multinucleated giant cells (84.2%, 32 of 38) and were not found within or adjacent to granulomas. Notably, the number of female patients with CD and Schaumann bodies was higher than that of males.

CONCLUSION

Schaumann bodies are common in resected CD specimens, and their characteristic deposition pattern may serve as a diagnostic indication for CD.

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.

Guardians of the gut: influence of the enteric nervous system on the intestinal epithelial barrier

The intestinal mucosal surface forms one of the largest areas of the body, which is in direct contact with the environment. Co-ordinated sensory functions of immune, epithelial, and neuronal cells ensure the timely detection of noxious queues and potential pathogens and elicit proportional responses to mitigate the threats and maintain homeostasis. Such tuning and maintenance of the epithelial barrier is constantly ongoing during homeostasis and its derangement can become a gateway for systemic consequences. Although efforts in understanding the gatekeeping functions of immune cells have led the way, increasing number of studies point to a crucial role of the enteric nervous system in fine-tuning and maintaining this delicate homeostasis. The identification of immune regulatory functions of enteric neuropeptides and glial-derived factors is still in its infancy, but has already yielded several intriguing insights into their important contribution to the tight control of the mucosal barrier. In this review, we will first introduce the reader to the current understanding of the architecture of the enteric nervous system and the epithelial barrier. Next, we discuss the key discoveries and cellular pathways and mediators that have emerged as links between the enteric nervous, immune, and epithelial systems and how their coordinated actions defend against intestinal infectious and inflammatory diseases. Through this review, the readers will gain a sound understanding of the current neuro-immune-epithelial mechanisms ensuring intestinal barrier integrity and maintenance of intestinal homeostasis.

The Interface between Inflammatory Bowel Disease, Neuroinflammation, and Neurological Disorders

Inflammatory Bowel Disease (IBD) is a complex, chronic inflammatory condition affecting the gastrointestinal tract. IBD has been associated with a variety of neurologic manifestations including peripheral nerve involvement, increased risk of thrombotic, demyelinating and events. Furthermore, an evolving association between IBD and neurodegenerative disorders has been recognized, and early data suggests an increased risk of these disorders in patients diagnosed with IBD. The relationship between intestinal inflammatory disease and neuroinflammation is complex, but the bidirectional interaction between the brain-gut-microbiome axis is likely to play an important role in the pathogenesis of these disorders. Identification of common mechanisms and pathways will be key to developing potential therapies. In this review, we discuss the evolving interface between IBD and neurological conditions, with a focus on clinical, mechanistic, and potentially therapeutic implications.

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.

Mise au point de l’utilisation de l’intelligence artificielle dans la prise en charge des maladies inflammatoires chroniques de l’intestin

Complexity of inflammatory bowel diseases (IBD) lies on their management and their biology. Clinics, blood and fecal samples tests, endoscopy and histology are the main tools guiding IBD treatment, but they generate a large amount of data, difficult to analyze by clinicians. Because of its capacity to analyze large number of data, artificial intelligence is currently generating enthusiasm in medicine, and this technology could be used to improve IBD management. In this review, after a short summary on IBD management and artificial intelligence, we will report pragmatic examples of artificial intelligence utilisation in IBD. Lastly, we will discuss the limitations of this technology.

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.

Constrictive and Hypertrophic Strictures in Ileal Crohn's Disease

BACKGROUND & AIMS

Strictures in Crohn's disease (CD) are classically attributed to fibromuscular hypertrophy of the intestinal wall. We have identified and characterized CD-related ileal strictures that result instead from mural constriction (ie, reduced external circumference).

METHODS

Twenty-four strictures and internal controls from 17 adults with obstructive CD were analyzed by cross-sectional morphometry.

RESULTS

The stricture-to-control circumference ratios (CRs) ranged from 0.53 to 1.7. Six strictures with CR ≥1.0, designated hypertrophic, had concentrically thickened walls, mean 3-fold increases in cross-sectional area and stainable fibromucular tissue, and high transmural inflammation scores. In contrast, 18 strictures with CR <1.0, designated constrictive, had thin, pliant walls, cross-sectional areas and stainable fibromuscular tissue comparable with control values, and low transmural inflammation scores. Eight mildly constrictive strictures also showed mild fibromuscular mural expansion that fell short of statistical significance. Twelve of 18 constrictive strictures (67%) occurred multiply (2-4 strictures per specimen) in contrast with hypertrophic strictures, all of which occurred singly (P = .01). Constriction correlated quantitatively with circumferential serosal fat wrapping (P = .003) and was associated with myenteric lymphocytic plexitis (P = .02). Disease duration was shortest among subjects with constrictive strictures and correlated with increasing circumference (CR ≤0.8, 6.3 ± 6.2 years; CR >0.8, 8.7 ± 6.4 years; and CR ≥1.00, 13.7 ± 5.0 years, respectively; P = .03).

CONCLUSIONS

Constrictive ileal strictures in CD differ pathologically and clinically from hypertrophic strictures, featuring little or no fibromuscular mural expansion, frequent multiplicity, and earlier onset. Mesenteric fat wrapping and myenteric plexitis may contribute to their pathogenesis. Pathologic manifestations of constriction and hypertrophy can coexist, suggesting that stricture heterogeneity may be shaped in part by the dynamics of constrictive and hypertrophic processes.

Composite outcomes in observational studies of Crohn's disease: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aims to assess composite and aggregate outcomes of observational studies in Crohn's disease and to evaluate whether the number and type of variables included affect the frequency of the outcome.

METHODS

MEDLINE [via PubMed], Scopus and Web of Science were searched to identify observational studies that enrolled patients with Crohn's disease and evaluated a composite or aggregate outcome. The proportion of patients achieving the outcome was determined and a random-effects meta-analysis was performed to evaluate how the frequency of each outcome varies according to the reporting of predefined variables.

RESULTS

From 10,257 identified records, 46 were included in the qualitative analysis and 38 in the meta-analysis. The frequency for composite and aggregate outcomes was 0.445 [95% confidence interval (CI): 0.389-0.501] and 0.140 (95% CI: 0.000-0.211), respectively. When comparing composite outcomes by number of included variables, the frequency was 0.271 (95% CI: 0.000-0.405) and 0.698 (95% CI: 0.651-0.746), for one and six variables, respectively. The frequency of the composite outcome varied according to the identity of the variables being reported. Specific pairs of predefined variables had a significant effect in the frequency of composite outcomes.

CONCLUSION

Composite outcomes with increasing number of predefined variables show an increase in frequency. Outcomes including variables such as 'Surgery' and 'Steroids' had higher frequencies when compared with the ones that did not include these variables. These results show that the frequency of composite outcomes is dependent on the number and type of variables being reported.

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.

Enteric glial cell heterogeneity regulates intestinal stem cell niches

The high turnover and regenerative capacity of the adult intestine relies on resident stem cells located at the bottom of the crypt. The enteric nervous system consists of an abundant network of enteric glial cells (EGCs) and neurons. Despite the close proximity of EGCs to stem cells, their in vivo role as a stem cell niche is still unclear. By analyzing the mouse and human intestinal mucosa transcriptomes at the single-cell level, we defined the regulation of EGC heterogeneity in homeostasis and chronic inflammatory bowel disease. Ablation of EGC subpopulations revealed that the repair potential of intestinal stem cells (ISCs) is regulated by a specific subset of glial fibrillary acidic protein (GFAP)⁺ EGCs. Mechanistically, injury induces expansion of GFAP⁺ EGCs, which express several WNT ligands to promote LGR5⁺ ISC self-renewal. Our work reveals the dynamically regulated heterogeneity of EGCs as a key part of the intestinal stem cell niche in regeneration and disease.

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.

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.

The enteric nervous system in gastrointestinal disease etiology

A highly conserved but convoluted network of neurons and glial cells, the enteric nervous system (ENS), is positioned along the wall of the gut to coordinate digestive processes and gastrointestinal homeostasis. Because ENS components are in charge of the autonomous regulation of gut function, it is inevitable that their dysfunction is central to the pathophysiology and symptom generation of gastrointestinal disease. While for neurodevelopmental disorders such as Hirschsprung, ENS pathogenesis appears to be clear-cut, the role for impaired ENS activity in the etiology of other gastrointestinal disorders is less established and is often deemed secondary to other insults like intestinal inflammation. However, mounting experimental evidence in recent years indicates that gastrointestinal homeostasis hinges on multifaceted connections between the ENS, and other cellular networks such as the intestinal epithelium, the immune system, and the intestinal microbiome. Derangement of these interactions could underlie gastrointestinal disease onset and elicit variable degrees of abnormal gut function, pinpointing, perhaps unexpectedly, the ENS as a diligent participant in idiopathic but also in inflammatory and cancerous diseases of the gut. In this review, we discuss the latest evidence on the role of the ENS in the pathogenesis of enteric neuropathies, disorders of gut-brain interaction, inflammatory bowel diseases, and colorectal cancer.

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.

The Predictive Value of Inflammation at Ileocecal Resection Margins for Postoperative Crohn's Recurrence: A Cohort Study

BACKGROUND

Resections for Crohn's disease should be limited and only resect macroscopically affected bowel. However, recent studies suggest microscopic inflammation at resection margins as a predictor for postoperative recurrence. The clinical impact remains unclear, as non-uniform pathological criteria have been used. The aim of this study was to assess the predictive value of pathological characteristics at ileocecal resection margins for recurrence.

METHODS

Both resection margins of 106 consecutive patients undergoing ileocecal resection for Crohn's disease between 2002 and 2009 were revised and scored for active inflammation, myenteric plexitis, and granulomas. Pathological findings were correlated to recurrence, defined as recurrent disease activity demonstrated by endoscopy (modified Rutgeerts score ≥i2) requiring upscaling medical treatment, using multivariate analysis.

RESULTS

Active inflammation was found at the proximal and distal resection margin in 27% and 15% of patients, respectively, myenteric plexitis in 37% and 32%, respectively, and granulomas in 4% and 6%, respectively. In total, 47 out of 106 patients developed recurrence. Only active inflammation at the distal colonic resection margin was an independent significant predictor for recurrence (88% vs 43% vs 51% for distal, proximal, and no involved margins, respectively; P < 0.01).

CONCLUSION

Active inflammation at the distal colonic resection margin after ileocecal resection identifies a patient group at high risk for postoperative recurrence both at the anastomotic site and the colon because it identifies undiagnosed L3 disease. These patients have a different and more aggressive natural history and require more intense medical treatment. Therefore, pathological evaluation of the distal resection margin should be implemented in daily practice.

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.

Prominence of ileal mucosa-associated microbiota to predict postoperative endoscopic recurrence in Crohn's disease

OBJECTIVE

Following ileal resection for Crohn's disease (CD), recurrence is very frequent. Although several clinical risk factors of recurrence have been identified, predicting relapse remains challenging. Performing an ileocolonoscopy within the first year after surgery is currently recommended to assess endoscopic recurrence and to adjust the treatment. We took advantage of a large prospective multicentric cohort to investigate the role of the ileal mucosa-associated microbiota in postoperative endoscopic recurrence.

PATIENTS AND METHODS

Ileal mucosa-associated microbiota was analysed by 16S sequencing at the time of surgery and/or of endoscopic evaluation in 201 patients (288 samples in total) prospectively recruited in France.

RESULTS

Ileal mucosa-associated microbiota exhibits profound changes following surgery in CD. Compared with non-recurrence setting, endoscopic recurrence is associated with strong changes in ileal mucosa-associated microbiota that are highly reminiscent of those observed generally in ileal CD compared with healthy subjects with a reduction in alpha diversity, an increase in several members of the Proteobacteria phylum and a decrease in several members of the Lachnospiraceae and the Ruminococcaceae families within the Firmicutes phylum. At the time of surgery, we identified several bacterial taxa associated with endoscopic recurrence and that can better predict relapse than usual clinical risk factors.

CONCLUSION

Surgery has an important impact on ileal mucosa-associated microbiota. Postoperative endoscopic recurrence is associated with changes in microbiota composition and alpha diversity. The gut microbiota has the potential to predict postoperative evolution and recurrence.

Histopathology Scoring Systems of Stenosis Associated With Small Bowel Crohn's Disease: A Systematic Review

BACKGROUND & AIMS

Stenosis is a common complication of Crohn's disease (CD) that has no effective medical therapy. Development of antifibrotic agents will require testing in randomized controlled trials. Computed tomography enterography- and magnetic resonance enterography-based technologies might be used to measure outcomes in these trials. These approaches have been validated in studies of patients with symptomatic strictures who underwent imaging evaluations followed by resection with histopathologic grading of the intestinal tissue for inflammation and/or fibrosis (the reference standard). Imaging findings have correlated with findings from quantitative or semiquantitative histologic evaluation of the degree of fibromuscular stenosis and/or inflammation on the resection specimen. However, it is not clear whether histologic findings are an accurate reference standard. We performed a systematic review of all published histologic scoring systems used to assess stenosing CD.

METHODS

We performed a comprehensive search of Embase and MEDLINE of studies through March 13, 2019, that used a histologic scoring system to characterize small bowel CD and assessed inflammatory and fibrotic alterations within the same adult individual. All scores fitting the criteria were included in our analysis, independent of the presence of stricturing disease, as long as inflammation and fibrosis were evaluated separately but in the same scoring system.

RESULTS

We observed substantial heterogeneity among the scoring systems, which were not derived from modern principles for evaluative index development. None had undergone formal validity or reliability testing. None of the existing indices had been constructed according to accepted methods for the development of evaluative indices. Basic knowledge regarding their operating properties were lacking. Specific indices for evaluating the important pathologic component of myofibroblast hypertrophy or hyperplasia have not been proposed.

CONCLUSIONS

In a systematic review of publications, we found a lack of validated histopathologic scoring systems for assessment of fibromuscular stenosis. Data that describe the operating properties of existing cross-sectional imaging techniques for stenosing CD should be questioned. Development and validation of a histopathology index is an important research priority.

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.

Endoscopy in Postoperative Patients with Crohn's Disease or Ulcerative Colitis. Does It Translate to Better Outcomes?

This article discusses the use of endoscopy in patients with Crohn disease and ulcerative colitis in the postoperative setting. Endoscopy is the most sensitive and validated tool available in the diagnosis of recurrence of Crohn disease in the postoperative setting. It is also the most effective diagnostic modality available for evaluating complications of pouch anatomy in patients with ulcerative colitis. In addition to diagnosis, management postoperatively can be determined through endoscopy.

What is the role of histopathology in the evaluation of disease activity in Crohn's disease?

Assessment of disease activity is essential for developing and determining appropriate therapy in patients with Crohn's disease. Currently, clinical and endoscopic treatment targets have been proposed, whereas histologic assessment of disease activity is not recommended in expert guidelines. Histologic assessment of disease activity has emerged as an important tool in ulcerative colitis as persistent histological inflammation is associated with clinical relapse, corticosteroid use, hospitalisation, and development of dysplasia. Similar data for Crohn's disease is limited but emerging literature suggests that histologic evaluation of disease activity may have value. This review summarizes the recent literature regarding histologic evaluation of disease activity in Crohn's disease. Correlation between histologic, endoscopic, and other markers of disease activity are discussed. Histologic scoring systems in Crohn's disease are described and practical guidance is provided to gastroenterologists and pathologists on how to report and interpret histologic data.

Increased nerve twigs in small intestinal mucosa with programmed cell death-ligand 1 and somatostatin receptor type 2A expression in recurrent Crohn disease: A case report

RATIONALE

Inflammatory bowel disease (IBD) patients manifest symptoms of disturbed gut function, such as neural sensory-motor changes. Programmed cell death-ligand 1 (PD-L1), normally present in neural tissue, exists in close apposition to the mucosal immune system and intestinal epithelium, and a bi-directional communication is known to occur at these interfaces. Somatostatin has been shown to suppress the inflammatory reaction, and has been used in several clinical trials to treat inflammatory disorders, such rheumatoid arthritis. Recently, somatostatin receptor type 2A, that regulates neurotransmission, proliferation, and apoptosis, has been recognized in IBD. Although prominent abnormalities in the morphology of the enteric nervous system have been observed in idiopathic IBD, they are more marked in Crohn disease.

PATIENT CONCERNS

A 55-year-old woman with recurrent Crohn disease, just surgically treated for ileal resection, have a stenotic complication.

INTERVENTIONS

At surgery 5 cm of preterminal ileum with stenosis and anastomotic ileocolic block was removed.

DIAGNOSES

The histopathology showed a recurrent Crohn in fistulo-stenotic phase; the stenosis was mainly sustained by mass-forming, ganglioneuromatous hyperplasia. Normally very rare, fine nerve twigs extend up into mucosa but we found a new-formed fibrillary network, extending into the inflammation area at the subepithelial luminal site of the mucosa, that was positive to PD-L1 and somatostatin receptor type 2A (SSTR2A) immunostaining but not visualized in routinary stained slides.

OUTCOMES

After surgery the patient was semestrally followed with clinical endoscopic evaluation that results uneventfully.

LESSONS

Our case shows that before surgery neuromatous abnormalities can be predicted by immunostained new-formed twigs in the mucosa.

Mesenteric Lymphatic Vessel Density Is Associated with Disease Behavior and Postoperative Recurrence in Crohn's Disease

PURPOSE

The aims of the present study were to examine the density of lymphatic vessels in the mesentery and to assess the predictive value of the mesenteric lymphatic vessel density for postoperative clinical recurrence.

METHODS

Ileocolonic resection specimens were obtained from 53 patients with Crohn's disease and 10 non-inflammatory bowel disease control subjects. Mesentery adipose tissues adjacent to the bowel wall were used for the histological quantification of lymphatic vessels using immunohistochemistry with the D2-40 antibody. The relationships between lymphatic vessel density and disease behavior, the presence of granulomas, the presence of creeping fat, and postoperative clinical recurrence were assessed.

RESULTS

Median lymphatic vessel density in the mesentery adjacent to inflamed or non-inflamed intestine was lower in control subjects than in Crohn's disease patients (2.13‰; interquartile range [IQR], 1.83-2.61; 8.34‰; IQR, 6.39-10.22; 4.43‰; IQR, 3.32-5.78; P ˂ 0.001). Increased mesenteric lymphatic vessel density was significantly associated with stricturing behavior, the presence of intestinal granulomas, the presence of creeping fat, and bowel thickness. Interestingly, patients with disease recurrence had an increased mesenteric lymphatic vessel density of the proximal mesenteric margin at the time of resection compared with those who did not have disease recurrence (6.23‰; IQR, 5.43-6.75 vs. 3.28‰; IQR, 2.93-4.29; P ˂ 0.001).

CONCLUSIONS

In addition to its correlation with disease behavior, bowel thickness, and the presence of intestinal granulomas and creeping fat, increased mesenteric lymphatic vessel density in the proximal margin is predictive of early clinical recurrence after surgery in patients with Crohn's disease.

The Clinical Significance of Crohn Disease Activity at Resection Margins

Context.—

Conflicting data about the clinical significance of microscopic Crohn disease (CD) activity at resection margins have led to varying practice patterns for routine reporting by pathologists.

Objective.—

To characterize the association between active disease at resection margins with postoperative CD recurrence and time-to-recurrence in the era of anti–tumor necrosis factor therapy.

Design.—

We performed a multicenter retrospective cohort study of 101 consecutive CD bowel resections during 10 years. Margin slides were reviewed, and CD activity at the margins was graded as none, mild, moderate, or severe. The association between microscopic CD activity at the margin with postoperative recurrence and time-to-recurrence were evaluated with logistic regression and Cox regression analyses, respectively.

Results.—

Crohn disease activity at resection margins was reported in 43% of pathology reports. Resection margins had CD involvement in 39.6% of cases, 20 of which were classified as mild, 6 as moderate, and 12 with severe CD activity. Although patients with mild (odds ratio, 1.14; 95% CI, 0.40–3.20) and moderate to severe (odds ratio, 1.97; 95% CI, 0.62–6.35) activity were at increased risk of disease recurrence, the differences were not statistically significant. Patients with mild (hazard ratio, 0.97; 95% CI, 0.50–1.91) and moderate to severe (hazard ratio, 1.29; 95% CI, 0.65–2.55) disease activity at margins did not have significantly different time-to-recurrence compared with those without disease activity.

Conclusions.—

Our study suggests CD activity at resection margins is not significantly associated with postoperative CD recurrence.

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.

Increased enteric glial cells in proximal margin of resection is associated with postoperative recurrence of Crohn's disease

BACKGROUND AND AIM

The enteric nervous system can amplify or modulate intestinal inflammation through secretion of neuropeptides, and enteric glial cells have been implicated in the pathophysiology of Crohn's disease. The goal of the study was to search for an association between the density of neurons, neuropeptides, and enteric glial cells and postoperative recurrence.

METHODS

The ileal proximal uninflamed section from ileocolonic sample was studied using immunohistochemistry with antibodies directed against vasoactive intestinal polypeptide (VIP), substance P (SP), neuron-specific enolase (NSE), and the glial marker protein S100. The density in the submucosa was calculated, and the relationship of the density of VIP, SP, NSE, and S100 and postoperative disease recurrence was assessed.

RESULTS

There were no significant differences between patients with and without postoperative endoscopic recurrence or clinical recurrence for the density of NSE-positive, VIP-positive, or SP-positive neurons in the proximal margin. Interestingly, the density of S100-positive enteric glial cells was significantly increased in patients with endoscopic and clinical recurrence than in subjects without disease recurrence (P ˂ 0.001). The density of S100-positive enteric glial cells was independently associated with postoperative disease recurrence.

CONCLUSIONS

Increased S100-positive enteric glial cells are associated with a high risk of both endoscopic and clinical recurrence after surgery. These findings have implications in individualized postoperative prophylaxis for Crohn's disease.

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.

Analysis of risk factors - especially different types of plexitis - for postoperative relapse in Crohn’s disease

AIM

To evaluate the presence of submucosal and myenteric plexitis and its role in predicting postoperative recurrence.

METHODS

Data from all patients who underwent Crohn’s disease (CD)-related resection at the University of Szeged, Hungary between 2004 and 2014 were analyzed retrospectively. Demographic data, smoking habits, previous resection, treatment before and after surgery, resection margins, neural fiber hyperplasia, submucosal and myenteric plexitis were evaluated as possible predictors of postoperative recurrence. Histological samples were analyzed blinded to the postoperative outcome and the clinical history of the patient. Plexitis was evaluated based on the appearance of the most severely inflamed ganglion or nerve bundle. Patients underwent regular follow-up with colonoscopy after surgery. Postoperative recurrence was defined on the basis of endoscopic and clinical findings, and/or the need for additional surgical resection.

RESULTS

One hundred and four patients were enrolled in the study. Ileocecal, colonic, and small bowel resection were performed in 73.1%, 22.1% and 4.8% of the cases, respectively. Mean disease duration at the time of surgery was 6.25 years. Twenty-six patients underwent previous CD-related surgery. Forty-three point two percent of the patients were on 5-aminosalicylate, 20% on corticosteroid, 68.3% on immunomodulant, and 4% on anti-tumor necrosis factor-alpha postoperative treatment. Postoperative recurrence occurred in 61.5% of the patients; of them 39.1% had surgical recurrence. 92.2% of the recurrences developed within the first five years after the index surgery. Mean disease duration for endoscopic relapse was 2.19 years. The severity of submucosal plexitis was a predictor of the need for second surgery (OR = 1.267, 95%CI: 1.000-1.606, P = 0.050). Female gender (OR = 2.21, 95%CI: 0.98-5.00, P = 0.056), stricturing disease behavior (OR = 3.584, 95%CI: 1.344-9.559, P = 0.011), and isolated ileal localization (OR = 2.671, 95%CI: 1.033-6.910, P = 0.043) were also predictors of postoperative recurrence. No association was revealed between postoperative recurrence and smoking status, postoperative prophylactic treatment and the presence of myenteric plexitis and relapse.

CONCLUSION

The presence of severe submucosal plexitis with lymphocytes in the proximal resection margin is more likely to result in postoperative relapse in CD.

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.

Surgical Management of Crohn Disease in Children: Guidelines From the Paediatric IBD Porto Group of ESPGHAN

The incidence of Crohn disease (CD) has been increasing and surgery needs to be contemplated in a substantial number of cases. The relevant advent of biological treatment has changed but not eliminated the need for surgery in many patients. Despite previous publications on the indications for surgery in CD, there was a need for a comprehensive review of existing evidence on the role of elective surgery and options in pediatric patients affected with CD. We present an expert opinion and critical review of the literature to provide evidence-based guidance to manage these patients. Indications, surgical options, risk factors, and medications in pre- and perioperative period are reviewed in the light of available evidence. Risks and benefits of surgical options are addressed. An algorithm is proposed for the management of postsurgery monitoring, timing for follow-up endoscopy, and treatment options.

The neuroprotective effects of human bone marrow mesenchymal stem cells are dose-dependent in TNBS colitis

Background

The incidence of inflammatory bowel diseases (IBD) is increasing worldwide with patients experiencing severe impacts on their quality of life. It is well accepted that intestinal inflammation associates with extensive damage to the enteric nervous system (ENS), which intrinsically innervates the gastrointestinal tract and regulates all gut functions. Hence, treatments targeting the enteric neurons are plausible for alleviating IBD and associated complications. Mesenchymal stem cells (MSCs) are gaining wide recognition as a potential therapy for many diseases due to their immunomodulatory and neuroprotective qualities. However, there is a large discrepancy regarding appropriate cell doses used in both clinical trials and experimental models of disease. We have previously demonstrated that human bone marrow MSCs exhibit neuroprotective and anti-inflammatory effects in a guinea-pig model of 2,4,6-trinitrobenzene-sulfonate (TNBS)-induced colitis; but an investigation into whether this response is dose-dependent has not been conducted.

Methods

Hartley guinea-pigs were administered TNBS or sham treatment intra-rectally. Animals in the MSC treatment groups received either 1 × 10⁵, 1 × 10⁶ or 3 × 10⁶ MSCs by enema 3 hours after induction of colitis. Colon tissues were collected 72 hours after TNBS administration to assess the effects of MSC treatments on the level of inflammation and damage to the ENS by immunohistochemical and histological analyses.

Results

MSCs administered at a low dose, 1 × 10⁵ cells, had little or no effect on the level of immune cell infiltrate and damage to the colonic innervation was similar to the TNBS group. Treatment with 1 × 10⁶ MSCs decreased the quantity of immune infiltrate and damage to nerve processes in the colonic wall, prevented myenteric neuronal loss and changes in neuronal subpopulations. Treatment with 3 × 10⁶ MSCs had similar effects to 1 × 10⁶ MSC treatments.

Conclusions

The neuroprotective effect of MSCs in TNBS colitis is dose-dependent. Increasing doses higher than 1 × 10⁶ MSCs demonstrates no further therapeutic benefit than 1 × 10⁶ MSCs in preventing enteric neuropathy associated with intestinal inflammation. Furthermore, we have established an optimal dose of MSCs for future studies investigating intestinal inflammation, the enteric neurons and stem cell therapy in this model.