Myenteric plexitis at the proximal resection margin is a predictive marker for surgical recurrence of ileocaecal Crohn's disease

Resolving Resident Colonic Muscularis Macrophage Diversity and Plasticity During Colitis

BACKGROUND

Immune cell populations in the intestinal muscularis propria during colitis are poorly resolved. Maintaining homeostasis in this niche is critical, highlighted by the poorer prognosis of inflammatory bowel disease associated with muscularis propria inflammation.

METHODS

This study utilizes single-cell RNA sequencing to survey the immune cell populations within the muscularis propria of normal colon and dextran sodium sulfate-induced colitis. Findings are validated by immunohistochemistry, flow cytometry and cell-lineage tracing in vivo, and in vitro assays with muscularis macrophages (MMφ).

RESULTS

In naïve conditions, transcriptional duality is observed in MMφs with 2 major subpopulations: conventional resident Cx3cr1+ MMφs and Lyve1+ MMφs. The Lyve1+ population is phagocytic and expresses several known MMφ markers in mouse and human, confirming their identity as a bona fide MMφ subset. Single-cell transcriptomics indicate that resident MMφs are retained during colitis and exhibit plasticity toward an inflammatory profile. Lyve1+ MMφs, which express anti-inflammatory marker CD163, are absent during colitis, as confirmed by flow cytometry. In contrast, lineage tracing finds that resident Cx3cr1+ MMφs remain during colitis and are not completely replaced by the inflammatory infiltrating monocytes. In vitro studies provide biological evidence of the plasticity of resident Cx3cr1+ MMφs in response to lipopolysaccharide (LPS), mirroring transcriptional observations in vivo of their inflammatory plasticity. Potential markers for colitic MMφs, validated in animal models and in individuals with ulcerative colitis, are identified.

CONCLUSIONS

Our findings contribute to the understanding of the immune system in the muscularis propria niche during colitis by resolving the heterogeneity and origins of colitic MMφs.

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.

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.

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.

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.

The Usefulness of Tissue Calprotectin in Pediatric Crohn’s Disease—A Pilot Study

Background: Fecal calprotectin (FCP) is a highly sensitive biomarker of intestinal inflammation widely used in diagnostics and monitoring of inflammatory bowel disease (IBD). Immunohistochemical assessment of calprotectin in the bowel mucosa is not a diagnostic standard. Therefore, the aim of this study was to evaluate tissue calprotectin (TCP) as a potential marker providing added insight for pediatric patients with Crohn’s disease (CD). Methods: Fecal and tissue calprotectin were measured in children with CD. The values were correlated with disease activity and histopathological changes of the patients’ endoscopic biopsies. Disease activity was assessed using the Pediatric Crohn’s Disease Activity Index (PCDAI); fecal calprotectin (FCP) was measured with the ELISA test. Immunohistochemical (IHC) staining for calprotectin antigen was performed on the biopsy samples from six bowel segments, and the number of TCP cells was counted per high power field (HPF). Non-parametric statistical tests were used for data analysis. Results: Fifty-seven children with CD with a median age of 10.5 (1–17) years (yrs) were examined for fecal and tissue calprotectin. The patients’ median PCDAI score was 10 (0–63.5), while median FCP was 535 (30–600) μg/g. We observed a correlation between disease activity (PCDAI) and FCP, TCP in inflammatory lesions and in crypts. There was no association either between FCP and TCP or between TCP in epithelium and PCDAI. Conclusion: It seems that IHC detection of calprotectin in bowel mucosa to assess disease behavior may be useful. FCP is a gold-standard biomarker in the diagnosis, monitoring and prognosis of IBD, and its levels correlated well with clinical activity in our study group.

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.

Intriguing Role of the Mesentery in Ileocolic Crohn's Disease

Crohn's disease (CD) is a chronic relapsing inflammatory bowel disease with unknown etiology. Up to 80% of patients will eventually require surgery throughout their lifetime, and often repeated resections are required for disease recurrence. Observations of “creeping fat” surrounding the diseased intestine renewed interest in the mesentery, recently defined as an organ with endocrine and immune functions. According to the inside-out model, the mesentery may be primarily affected in CD and subsequent cause alterations in the mucosa. Recently, lower surgical recurrence rates have been reported with en-bloc excision of the mesentery adjoining the diseased intestine. Results of ongoing randomized controlled trials may clarify the role of the mesentery in CD and possibly lead to its adoption as standard during surgery for Crohn's disease.

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.

Predictive value of tissue calprotectin for disease recurrence after ileocecal resection in pediatric Crohn's disease

AIM

Detection of possible predictive factors of endoscopic recurrence after ileocecal resection in Crohn's disease could be very beneficial for the individual adjustment of postoperative therapy. The aim of this study was to verify, whether immunohistochemical detection of calprotectin in resection margins is useful in diagnostics of endoscopic recurrence.

METHODS

In this study we included pediatric patients with Crohn's disease who underwent ileocecal resection, regardless of pre-operative or post-operative therapy (n=48). We collected laboratory, clinical, surgical, endoscopic and histopathological data at the time of surgery and at 6 months after surgery. The immunohistochemical staining of calprotectin antigen was performed on all paraffin blocks from the resection margins.

RESULTS

Out of 48 patients 52% had endoscopic recurrence in the anastomosis (defined by Rutgeerts score) within 6 months after surgery. The number of cells positive for calprotectin in the proximal resection margin was negatively associated with recurrence (P=0.008), as was the elevated level of total calprotectin (from both resection margins). There was no correlation of calprotectin in distal resection margin and endoscopic recurrence. Fecal calprotectin over 100 ug/g (P=0.0005) and high CRP (P<0.001) at 6 months after ileocecal resection and peritonitis (P=0.048) were associated with endoscopic recurrence.

CONCLUSION

Approximately half of the patients developed endoscopic recurrence within 6 months after ileocecal resection. The predictive value of tissue calprotectin is questionable, as it is negatively associated with endoscopic recurrence. There are other potentially useful predictors, such as CRP and fecal calprotectin at 6 months after resection and the presence of peritonitis.

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.

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.

Temporary faecal diversion in ileocolic resection for Crohn's disease: is there an impact on long-term surgical recurrence?

AIM

Temporary faecal diversion after ileocolic resection (ICR) for Crohn's disease reduces postoperative anastomotic complications in high-risk patients. The aim of this study was to assess if this approach also reduces long-term surgical recurrence.

METHOD

This was a multicentre retrospective review of prospectively maintained databases. Patient demographics, medical and surgical details were collected by three specialist centres. All patients had undergone an ICR between 2000 and 2012. The primary end-point was surgical recurrence.

RESULTS

Three hundred and twelve patients (80%) underwent an ICR without covering ileostomy (one stage). Seventy-seven (20%) had undergone an ICR with end ileostomy/double-barrel ileostomy/enterocolostomy followed by closure (two stage). The median follow-up was 105 months [interquartile range (IQR) 76-136 months]. The median time to ileostomy closure was 9 months (IQR 5-12 months). There was no significant difference in surgical recurrence between the one- and two-stage groups (18% vs 16%, P = 0.94). We noted that smokers (20% vs 34%, P = 0.01) and patients with penetrating disease (28% vs 52%, P < 0.01) were more likely to be defunctioned. A reduced recurrence rate was observed in the small high-risk group of patients who were smokers with penetrating disease behaviour treated with a two-stage strategy (0/10 vs 4/7, P = 0.12).

CONCLUSION

Despite having higher baseline risk factors, the results in terms of rate of surgical recurrence over 9 years are similar for patients having a two-stage compared with a one-stage procedure.

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.

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.

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 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.

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.

Submucosal Plexitis as a Predictive Factor for Postoperative Endoscopic Recurrence in Patients with Crohn's Disease Undergoing a Resection with Ileocolonic Anastomosis: Results from a Prospective Single-centre Study

AIM

Ileocolonoscopy allows early detection of recurrence after surgical resection for Crohn's disease [CD]. Plexitis, defined as presence of inflammatory cells in or around enteric ganglia or nerve bundles, in the proximal surgical margin has been associated with an increased overall recurrence risk. We investigated prospectively whether plexitis can predict endoscopic recurrence [ER] in a consecutive cohort of CD patients undergoing ileocolonic resection.

METHODS

All CD patients undergoing ileocolonic resection in our institution between October 2009 and December 2012 were eligible for this study. Clinical data were obtained prospectively from the patients' files, and biopsies from the proximal surgical margins were analysed immunohistochemically for inflammation at the myenteric and submucosal plexus [lymphocytes, mast cells, eosinophils]. The degree of plexitis was correlated with the presence of ER at 6 months, defined as a modified Rutgeerts' score of ≥ i2b. Multivariate models were developed and tested to predict posterior probability of ER.

RESULTS

A total of 74 patients were included. Six months after ileocolonic resection, 50% showed ER. Known risk factors such as penetrating disease, previous resections, and active smoking, showed no relation with ER. On the other hand, submucosal lymphocytic plexitis was associated with ER [p = 0.020]. The predictive value of lymphocytic cell count increased with more extensive biopsy sampling and with application of immunohistochemistry.

CONCLUSIONS

Submucosal lymphocytic plexitis in the proximal surgical margin was significantly related with a higher risk for ER after ileocolonic resection. These data support development of a postoperative prevention trial with vedolizumab, which may block lymphocytic trafficking in the postoperative bowel.

Complications and Disease Recurrence After Primary Ileocecal Resection in Pediatric Crohn's Disease: A Multicenter Cohort Analysis

BACKGROUND

Studies on the outcome of ileocecal resection in pediatric Crohn's disease (CD) have a limited follow-up and fail to assign predictors of adverse outcomes. Therefore, we aimed to investigate (I) the complication and disease recurrence rates and (II) identify risk factors for these adverse outcomes after ileocecal resection for pediatric CD.

METHODS

This is a retrospective cohort analysis of all children (<18 years) that underwent ileocecal resection as first intestinal resection for CD derived from 7 tertiary hospitals in the Netherlands (1990-2015). Risk factors were identified using multivariable analysis.

RESULTS

In total, 122 children were included (52% male; median age 15.5 years [interquartile range 14.0-16.0]). Severe postoperative complications rate was 10%. Colonic disease (odds ratio: 5.6 [95% confidence interval {CI}: 1.3-26.3], P = 0.024), microscopically positive resection margins (odds ratio: 10.4 [95% CI: 1.1-100.8] P = 0.043), and emergency surgery (odds ratio: 6.8 [95% CI: 1.1-42.2], P = 0.038) were risk factors for severe complications. Clinical and surgical recurrence rates after 1, 5 and 10 years were 19%, 49%, 71% and 2%, 12%, 22%, respectively. Female sex (hazard ratio [HR]: 2.1 [95% CI: 1.1-3.8], P = 0.023) was a risk factor for clinical recurrence, whereas ileocecal disease (HR: 3.9 [95% CI: 1.2-12.5], P = 0.024) and microscopically positive resection margins (HR: 9.6 [95% CI: 1.2-74.5], P = 0.031) were risk factors for surgical recurrence. Immediate postoperative therapy reduced the risk of both clinical (HR: 0.3 [95% CI: 0.1-0.6], P = 0.001) and surgical (HR: 0.5 [95% CI: 0.1-0.9], P = 0.035) recurrence.

CONCLUSIONS

Ileocecal resection is an effective and durable treatment of pediatric CD, although postoperative complications occur frequently. Postoperative therapy may be started immediately to prevent disease recurrence.

Factors affecting the incidence of early endoscopic recurrence after ileocolonic resection for Crohn's disease: a multicentre observational study

AIM

Early endoscopic recurrence is frequently observed in patients following resection for Crohn's disease (CD). However, factors affecting the incidence of an early postoperative endoscopic recurrence (EPER) have not been fully determined. The aim of this study was to evaluate risk factors for EPER after ileocolonic resection for CD.

METHOD

This was a retrospective, international multicentre study, in which 127 patients with a first ileocolonoscopy conducted between 6 and 12 months after ileocolonic resection for CD were included. Endoscopic recurrence was defined as a Rutgeerts score of ≥ i2. The following variables were investigated as potential risk factors for EPER: gender, age at surgery, location and behaviour of CD, smoking, concomitant perianal lesions, preoperative use of steroids, immunomodulators and biologics, previous resection, blood transfusion, surgical procedure (open vs laparoscopic approach), length of resected bowel, type of anastomosis (side-to-side vs end-to-end), postoperative complications, granuloma and postoperative biological therapy. Variables related to the patient, disease and surgical procedure were investigated as potential risk factors for EPER, with univariate and multivariate (logistic regression) analyses.

RESULTS

43/127 (34%) patients had EPER at the time of the first postoperative ileocolonoscopy. In univariate analysis, only preoperative steroid use was significantly associated with a higher rate of EPER [21/45 patients (47%) on steroids and 22/82 patients (27%) without steroids (P = 0.04)]. In multivariate analysis, only preoperative steroid use was a significant independent risk factor for EPER (odds ratio 3.28, 95% confidence interval: 1.30-8.28; P = 0.01).

CONCLUSIONS

This study found that only preoperative steroid use was a significant risk factor for EPER after ileocolonic resection for CD. Prospective studies are necessary to evaluate precisely the impact of perioperative medications on EPER rates.

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

BACKGROUND

As surgical resection is not curative in Crohn's disease, postoperative recurrence remains a crucial issue. The selection of patients, according to available risk factors, remains disappointing in clinical practice highlighting the need for better criteria, such as histologic features.

AIMS

To investigate whether submucosal and myenteric plexitis increase the risk of endoscopic, clinical and surgical postoperative recurrence in Crohn's disease.

METHODS

From the pathology department database, we retrospectively retrieved the data of all the patients who have undergone ileocolonic resection for Crohn's disease. Two pathologists, blinded from clinical data, reviewed all specimens to evaluate the presence of plexitis at the proximal resection margin.

RESULTS

Of the 75 included CD patients, 19 (25.3%) had histological involvement of resection margin. Inflammatory cells count for myenteric and submucosal plexus were performed in 56 patients. In multivariate analysis, the myenteric plexitis was a risk factor for endoscopic postoperative recurrence (HR 8.83 CI95% [1.6-48.6], p=0.012), and the presence of at least one myenteric lymphocyte (HR 4.02 CI95% [1.4-11.2], p=0.008) was predictive of clinical postoperative recurrence. We observed no histologic predictor for surgical postoperative recurrence.

CONCLUSION

Myenteric plexitis in proximal margins of ileocolonic resection specimens is independently associated with endoscopic and clinical postoperative recurrence in Crohn's disease.

Kono-S Anastomosis for Surgical Prophylaxis of Anastomotic Recurrence in Crohn's Disease: an International Multicenter Study

INTRODUCTION

The Kono-S (antimesenteric functional end-to-end handsewn) anastomosis has been used for Crohn's disease in Japan and the USA since 2003 and 2010, respectively. This technique was designed to reduce the risk of anastomotic surgical recurrence. This study reviews the outcomes a decade after the introduction of the Kono-S anastomosis to clinical practice.

METHODS

This study was conducted at five hospitals (four in Japan and one in the USA). A total of 187 patients in Japan (144 patients, group J) and the USA (43 patients, group US) who underwent Kono-S anastomosis for Crohn's disease between September 2003 and September 2011 were included.

RESULTS

With a median follow-up of 65 months, two surgical anastomotic recurrences have occurred in group J. Kaplan-Meier analysis showed that 5 and 10 years surgical recurrence-free survival rate was 98.6% in group J. No surgical anastomotic recurrences have been detected in group US with a median follow-up of 32 months. The Kono-S anastomosis was technically feasible and performed in all patients.

CONCLUSION

The Kono-S anastomosis appears to be safe and effective in reducing the risk of surgical recurrence in Crohn's disease.

How to predict clinical relapse in inflammatory bowel disease patients

Inflammatory bowel diseases have a natural course characterized by alternating periods of remission and relapse. Disease flares occur in a random way and are currently unpredictable for the most part. Predictors of benign or unfavourable clinical course are required to facilitate treatment decisions and to avoid overtreatment. The present article provides a literature review of the current evidence on the main clinical, genetic, endoscopic, histologic, serologic and fecal markers to predict aggressiveness of inflammatory bowel disease and discuss their prognostic role, both in Crohn’s disease and ulcerative colitis. No single marker seems to be reliable alone as a flare predictor, even in light of promising evidence regarding the role of fecal markers, in particular fecal calprotectin, which has reported good results recently. In order to improve our daily clinical practice, validated prognostic scores should be elaborated, integrating clinical and biological markers of prognosis. Finally, we propose an algorithm considering clinical history and biological markers to intercept patients with high risk of clinical relapse.