Natural history, diagnosis and treatment approach to fibrostenosing Crohn's disease

Radiomics to Detect Inflammation and Fibrosis on Magnetic Resonance Enterography in Stricturing Crohn's Disease

BACKGROUND AND AIMS

Non-invasive cross-sectional imaging via magnetic resonance enterography [MRE] offers excellent accuracy for the diagnosis of stricturing complications in Crohn's disease [CD] but is limited in determining the degrees of fibrosis and inflammation within a stricture. We developed and validated a radiomics-based machine-learning model for separately characterizing the degree of histopathological inflammation and fibrosis in CD strictures and compared it to centrally read visual radiologist scoring of MRE.

METHODS

This single-centre, cross-sectional study included 51 CD patients [n = 34 for discovery; n = 17 for validation] with terminal ileal strictures confirmed on diagnostic MRE within 15 weeks of resection. Histopathological specimens were scored for inflammation and fibrosis and spatially linked with corresponding pre-surgical MRE sequences. Annotated stricture regions on MRE were scored visually by radiologists as well as underwent 3D radiomics-based machine learning analysis; both were evaluated against histopathology.

RESULTS

Two distinct sets of radiomic features capturing textural heterogeneity within strictures were linked with each of severe inflammation or severe fibrosis across both the discovery (area under the curve [AUC = 0.69, 0.83] and validation [AUC = 0.67, 0.78] cohorts. Radiologist visual scoring had an AUC = 0.67 for identifying severe inflammation and AUC = 0.35 for severe fibrosis. Use of combined radiomics and radiologist scoring robustly augmented identification of severe inflammation [AUC = 0.79] and modestly improved assessment of severe fibrosis [AUC = 0.79 for severe fibrosis] over individual approaches.

CONCLUSIONS

Radiomic features of CD strictures on MRE can accurately identify severe histopathological inflammation and severe histopathological fibrosis, as well as augment performance of the radiologist visual scoring in stricture characterization.

KONO-S Anastomosis Is Not Superior to Conventional Anastomosis for the Reduction of Postoperative Endoscopic Recurrence in Crohn's Disease

BACKGROUND

Surgical resection rates remain high in Crohn's disease (CD). Reducing postoperative recurrence (POR) is challenging. Besides drug therapy, the surgical anastomosis technique may reduce POR. We aimed to compare the endoscopic POR rate after Kono-S vs standard ileocolic anastomosis.

METHODS

The study included all consecutive CD patients operated on for ileocolic resection with a Kono-S anastomosis between February 2020 and March 2022. These patients were prospectively followed, and colonoscopy was performed 6 to 12 months after surgery. Patients were compared with a historical cohort of patients operated on with a conventional anastomosis in the same center. The primary end point was endoscopic POR (Rutgeerts score ≥i2). Factors associated with POR were assessed by univariate and multivariable analyses.

RESULTS

A total of 85 patients were included, 30 in the Kono-S group and 55 in the control group. At baseline, there was no significant difference between the 2 groups regarding CD characteristics or known POR risk factors, including previous exposure to biologics. At 6 to 12 months, endoscopic POR rate did not differ significantly between groups (56.7% in the Kono-S group vs 49.1% in the control group; P = .50), nor did endoscopic POR according to the modified Rutgeerts score ≥i2b (46.7% in the Kono-S group vs 40% in the control group; P = .55). Severe endoscopic POR rates were 23.3% and 18.2% in each group, respectively. Clinical recurrence rate was similar in both groups, and no recurrent surgery occurred. By multivariable analysis, the type of anastomosis was not associated with endoscopic POR (OR, 1.229; 95% CI, 0.461-3.274, P = .68); however, postoperative treatment with anti-TNF was (OR, 0.337; 95% CI, 0.131-0.865 P = .02).

CONCLUSIONS

Kono-S anastomosis was not associated with a reduced rate of endoscopic POR. These results warrant confirmation in prospective, randomized, multicenter studies.

Imaging and clinical predictors of surgery in stricturing ileal Crohn's disease: a retrospective study from a large pediatric hospital

PURPOSE

(1) To determine the frequency of surgical management in children with Crohn's Disease (CD) and a new radiologic ileal stricture, and (2) to identify imaging and clinical features that predict the need for surgery.

METHODS

This retrospective study included pediatric patients (< 21 years old) with CD and a new ileal stricture diagnosed by MRE, CTE, or CT between July 2018 and June 2023. Three board-certified radiologists recorded stricture length, maximum mural thickness, minimum lumen diameter, maximum upstream diameter, and simplified magnetic resonance index of activity (sMaRIA) score. Anthropometrics, laboratory data, and surgical interventions performed after stricture diagnosis were also recorded. Multivariable logistic regression was used to identify imaging and clinical variables associated with the need for surgery.

RESULTS

44 pediatric CD patients (median age 16.5 years) presented with a new ileal stricture during the study period. 30 (68.2%) patients required surgery, with a median time of 87.5 days between stricture diagnosis and surgery. Median stricture measurements were length: 7.0 cm, maximum mural thickness: 7.3 mm, minimum lumen diameter: 0.2 cm, and maximum upstream diameter: 3.3 cm. Median sMaRIA score was 3.0, and 14 (31.8%) strictures had associated internal penetrating disease. Stricture ratio (ratio of maximum upstream lumen diameter to minimum lumen diameter) (OR = 1.15 [95% CI 1.02-1.30]; p = 0.02) and sMaRIA (OR = 2.12 [95% CI 0.87-5.17; p = 0.10) were associated with need for surgery.

CONCLUSION

Surgery remains common in stricturing pediatric CD, with increasing stricture ratio and sMaRIA score associated with need for surgical management.

Muscular hyperplasia in Crohn's disease strictures: through thick and thin

Fibrostenosing Crohn's disease (CD) represents a challenging clinical condition characterized by the development of symptomatic strictures within the gastrointestinal tract. Despite therapeutic advancements in managing inflammation, the progression of fibrostenotic complications remains a significant concern, often necessitating surgical intervention. Recent investigations have unveiled the pivotal role of smooth muscle cell hyperplasia in driving luminal narrowing and clinical symptomatology. Drawing parallels to analogous inflammatory conditions affecting other organs, such as the airways and blood vessels, sheds light on common underlying mechanisms of muscular hyperplasia. This review synthesizes current evidence to elucidate the mechanisms underlying smooth muscle cell proliferation in CD-associated strictures, offering insights into potential therapeutic targets. By highlighting the emerging significance of muscle thickening as a novel therapeutic target, this review aims to inform future research endeavors and clinical strategies with the goal to mitigate the burden of fibrostenotic complications in CD and other conditions.

Interventional endoscopy in inflammatory bowel disease: a comprehensive review

Interventional endoscopy can play a key role in the multidisciplinary management of complex inflammatory bowel disease (IBD) as an adjunct to medical and surgical therapy. The primary role of interventional IBD (IIBD) includes the treatment of Crohn's disease-related stricture, fistula, and abscess. Endoscopic balloon dilation (EBD), endoscopic stricturotomy, and placement of endoscopic stents are different forms of endoscopic stricture therapy. EBD is the most widely used therapy whereas endoscopic stricturotomy has higher long-term efficacy than EBD. Fully covered and partially covered self-expanding metal stents are useful in long and refractory strictures whereas lumen-apposing metal stents can be used in short, and anastomotic strictures. Endoscopic fistula/abscess therapy includes endoscopic fistulotomy, seton placement, endoscopic ultrasound-guided drainage of rectal/pelvic abscess, and endoscopic injection of filling agents (fistula plug/glue/stem cell). Endoscopic seton placement and fistulotomy are mainly feasible in short, superficial, single tract fistula and in those with prior surgical seton placement. Similarly, endoscopic fistulotomy is usually feasible in short, superficial, single-tract fistula. Endoscopic closure therapies like over-the-scope clips, suturing, and self-expanding metal stent should be avoided for de novo/bowel to hollow organ fistulas. Other indications include management of postoperative complications in IBD such as management of surgical leaks and complications of pouchitis in ulcerative colitis. Additional indications include endoscopic resection of ulcerative colitis-associated neoplasia (by endoscopic mucosal resection, endoscopic submucosal dissection, and endoscopic full-thickness resection), retrieval of retained capsule endoscope, and control of bleeding. IIBD therapies can potentially act as a bridge between medical and surgical therapy for properly selected IBD patients.

Aryl Hydrocarbon Receptor Activation Limits the Fatty Acid Synthesis and Subsequent "miR-193a-3p-HDAC3-FASN" Signals to Alleviate Intestinal Fibrosis

Intestinal fibrosis is a common complication of Crohn's disease and characterized by excessive extracellular matrix (ECM) deposition. The aryl hydrocarbon receptor (AhR) detects micronutrients and microbial metabolites in diet and can attenuate intestinal fibrosis with unclear mechanisms. In this study, AhR activation was demonstrated to downregulate the transcription of collagen I and fibronectin in a Sp1- but not Sp3- or AP-1-dependent manner. A suppressed fatty acid synthesis was highlighted using untargeted metabolomics analyses, and synthetic products, palmitic acid (PA), were used as the intermediary agent. After a screening study, fatty acid synthase (FASN) was identified as the main targeted protein, and AhR activation regulated "HDAC3-acetylation" signals but not glycosylation to enhance FASN degradation. Furthermore, results of bioinformatics analysis and others showed that after being activated, AhR targeted miR-193a-3p to control HDAC3 transcription. Collectively, AhR activation inhibited ECM deposition and alleviated intestinal fibrosis by limiting fatty acid synthesis subsequent to the inhibition of "miR-193a-3p-HDAC3-FASN" signals.

Inflammatory Bowel Disease: Immune Function, Tissue Fibrosis and Current Therapies

Inflammatory Bowel Disease (IBD) is a complex and challenging health problem that exerts a significant impact on the quality of life of millions of individuals worldwide [...].

Fibrostenosing Crohn's Disease: Pathogenetic Mechanisms and New Therapeutic Horizons

Bowel strictures are well recognized as one of the most severe complications in Crohn's disease, with variable impacts on the prognosis and often needing surgical or endoscopic treatment. Distinguishing inflammatory strictures from fibrotic ones is of primary importance due to the different therapeutic approaches required. Indeed, to better understand the pathogenesis of fibrosis, it is crucial to investigate molecular processes involving genetic factors, cytokines, alteration of the intestinal barrier, and epithelial and endothelial damage, leading to an increase in extracellular matrix synthesis, which ultimately ends in fibrosis. In such a complex mechanism, the gut microbiota also seems to play a role. A better comprehension of molecular processes underlying bowel fibrosis, in addition to radiological and histopathological findings, has led to the identification of high-risk patients for personalized follow-up and testing of new therapies, primarily in preclinical models, targeting specific pathways involving Transforming Growth Factor-β, interleukins, extracellular matrix balance, and gut microbiota. Our review aims to summarize current evidence about molecular factors involved in intestinal fibrosis' pathogenesis, paving the way for potential diagnostic biomarkers or anti-fibrotic treatments for stricturing Crohn's disease.

Does Kono-S Anastomosis Reduce Recurrence in Crohn's Disease Compared with Conventional Ileocolonic Anastomosis? A Nationwide Propensity Score-matched Study from GETAID Chirurgie Group [KoCoRICCO Study]

BACKGROUND AND AIMS

Postoperative recurrence is a major concern in Crohn's disease. The Kono-S anastomosis has been described to reduce the rate of recurrence. However, the level of evidence for its effectiveness remains low. The KoCoRICCO study aimed to compare outcomes between Kono-S anastomosis and conventional anastomosis in two nationwide, prospective cohorts.

METHODS

Adult patients with Crohn's disease, who underwent ileocolonic resection with Kono-S anastomosis, were prospectively included in seven referral centres between 2020 and 2022. Patients with conventional side-to-side anastomosis were enrolled from a previously published cohort. A propensity score analysis was performed to compare recurrence at first endoscopy in a matched 1:2 ratio population.

RESULTS

A total of 433 patients with ileocolonic anastomosis were enrolled, of whom 155 had a Kono-S anastomosis. Before matching, both groups were unbalanced for preoperative, intraoperative, and postoperative characteristics. After matching patients with available endoscopic follow-up, endoscopic recurrence ≥i2 was found in 47.5% of the Kono-S group and 44.3% of the conventional side-to-side group [p = 0.6745].

CONCLUSIONS

The KoCoRICCO study suggests that Kono-S anastomosis does not reduce the risk of endoscopic recurrence in Crohn's disease compared with conventional side-to-side anastomosis. Further research with a longer follow-up is necessary to determine whether there is a potential benefit on surgical recurrence.

Recent advances in intestinal fibrosis

Despite many progresses have been made in the treatment of inflammatory bowel disease, especially due to the increasing number of effective therapies, the development of tissue fibrosis is a very common occurrence along the natural history of this condition. To a certain extent, fibrogenesis is a physiological and necessary process in all those conditions characterised by chronic inflammation. However, the excessive deposition of extracellular matrix within the bowel wall will end up in the formation of strictures, with the consequent need for surgery. A number of mechanisms have been described in this process, but some of them are not yet clear. For sure, the main trigger is the presence of a persistent inflammatory status within the mucosa, which in turn favours the occurrence of a pro-fibrogenic environment. Among the main key players, myofibroblasts, fibroblasts, immune cells, growth factors and cytokines must be mentioned. Although there are no available therapies able to target fibrosis, the only way to prevent it is by controlling inflammation. In this review, we summarize the state of art of the mechanisms involved in gut fibrogenesis, how to diagnose it, and which potential targets could be druggable to tackle fibrosis.

Crohn's disease and clinical management today: How it does?

Crohn's Disease (CD) is an Inflammatory Bowel Disease and is characterized by an immune-mediated nature. Its etiology results from the interaction between genetic, enviromental and microbial factors. Regarding pathophysiology, it involves high levels of interleukin (IL)-12, IL-17, and Th1 profile, along with loss of tolerance mechanisms, an increase in pro-inflammatory interleukins, beyond the possibility to affect any part of the gastrointestinal tract. Its symptoms include abdominal pain, chronic diarrhea, weight loss, anorexia, and fatigue, as well as blood in the stool or rectum. Additionally, conditions comprising musculoskeletal, cutaneous, ocular, hepatic, and hematological alterations may be associated with this scenario and extra-intestinal presentation, such as erythema nodosum, anterior uveitis, osteoporosis, and arthritis can also occur. Today, clinical history, exams as fecal calprotectin, ileocolonocopy, and capsule endoscopy can be performed in the diagnosis investigation, along with treatments to induce and maintain remission. In this sense, anti-inflammatory drugs, such as corticosteroids, immunomodulators, and biological agents, as well as surgery and non-pharmacological interventions plays a role in its therapy. The aim of this review is to bring more current evidence to clinical management of CD, as well as to briefly discuss aspects of its pathophysiology, surveillance, and associated disorders.

Stricturing Crohn's disease: what is the role of endoscopic stenting? A systematic review

BACKGROUND/AIMS

Endoscopic stenting for stricturing Crohn's disease (CD) is an emerging treatment that achieves more persistent dilatation of the stricture over time than endoscopic balloon dilatation (EBD). We aimed to explore the efficacy and safety of stenting for the treatment of CD strictures.

METHODS

A systematic electronic literature search was performed (PROSPERO; no. CRD42022308033). The primary outcomes were technical success, efficacy, complication rate, and the need for further interventions due to reobstruction. The outcomes of partially covered self-expanding metal stents (PCSEMS) with scheduled retrieval after seven days were also analyzed.

RESULTS

Eleven eligible studies were included in the review. Overall, 173 patients with CD were included in this study. Mean percentage of technical success was 95% (range, 80%-100%), short-term efficacy was 100% in all studies, and long-term efficacy was 56% (range, 25%-90%). In patients with a scheduled PCSEMS retrieval, the long-term efficacy was 76% (range, 59%-90%), the mean complication rate was 35% (range, 15%-57%), and the major complication rate was 11% (range, 0%-29%).

CONCLUSION

Endoscopic stenting with scheduled PCSEMS retrieval may be considered a feasible second-line treatment for short CD strictures to postpone surgery. However, larger head-to-head prospective studies are needed to understand the role of stenting as an alternative or additional treatment to EBD in CD.

SIRT4 protects against intestinal fibrosis by facilitating GLS1 degradation

Intestinal fibrosis is a prevalent complication of Crohn's disease (CD), characterized by excessive deposition of extracellular matrix (ECM), and no approved drugs are currently available for its treatment. Sirtuin 4 (SIRT4), a potent anti-fibrosis factor in mitochondria, has an unclear role in intestinal fibrosis. In this study, fibroblasts isolated from biopsies of stenotic ileal mucosa in CD patients were analyzed to identify the most down-regulated protein among SIRT1-7, and SIRT4 was found to be the most affected. Moreover, in vivo and in vitro models of intestinal fibrosis, SIRT4 expression was significantly decreased in a TGF-β dependent manner, and its decrease was negatively associated with disease severity. SIRT4 impeded ECM deposition by inhibiting glutaminolysis, but not glycolysis, and α-ketoglutarate (α-KG) was identified as the key metabolite. Specifically, SIRT4 hinders SIRT5's stabilizing interaction with glutaminase 1 (GLS1), thereby facilitating the degradation of GLS1. KDM6, rather than KDM4, is a potential mediator for α-KG-induced transcription of ECM components, and SIRT4 enhances the enrichment of H3K27me3 on their promotors and enhancers. These findings indicate that the activation of TGF-β signals decreases the expression of SIRT4 in intestinal fibrosis, and SIRT4 can facilitate GLS1 degradation, thereby resisting glutaminolysis and alleviating intestinal fibrosis, providing a novel therapeutic target for intestinal fibrosis.

Factors associated with the efficacy and safety of endoscopic dilatation of symptomatic strictures in Crohn's disease: a retrospective cohort study

OBJECTIVE

Endoscopic balloon dilatation (EBD) is a standard treatment for intestinal strictures in Crohn's disease (CD). No evidence-based guidelines exist regarding the balloon diameter or the balloon pressure to be used, with recent studies suggesting the use of a smaller diameter than classically used. We sought to analyze the factors associated with safety and efficacy of EBD in CD strictures, particularly looking at balloon diameter and dilatation pressure.

METHODS

We conducted a monocentric retrospective study of patients who underwent EBD between 2005 and 2020.

RESULTS

Our endoscopy department performed EBD in 94 CD patients during the considered period. The mean size of balloon dilatation was 16 mm (±2.5; including 21 patients with balloon <14 mm) and the mean dilatation pressure was 5.3 atm (±1.5). No perforation was observed. Over a median follow-up of 5.6 years, the probability of being operated was 5.4% at 1 year and 10.4% at 3 years. Smaller height (HR = 0.90, p = 0.022) and a higher BMI (HR = 1.23, p = 0.014) were associated with the risk of operation. The probability of being operated or redilated was 30.1% at 1 year and 52.5% at 3 years. No factor was significantly associated with this risk. The size of the balloon had no impact on outcomes.

CONCLUSION

In this retrospective cohort, including a significant proportion of CD patients dilated with balloon <14 mm, no perforation was observed and the size of the balloon or the dilatation pressure had no impact on the risk of surgery or redilatation.

Fibro-Stenosing Crohn's Disease: What Is New and What Is Next?

Fibro-stenosing Crohn's disease (CD) is a common disease presentation that leads to impaired quality of life and often requires endoscopic treatments or surgery. From a pathobiology perspective, the conventional view that intestinal fibro-stenosis is an irreversible condition has been disproved. Currently, there are no existing imaging techniques that can accurately quantify the amount of fibrosis within a stricture, and managing patients is challenging, requiring a multidisciplinary team. Novel therapies targeting different molecular components of the fibrotic pathways are increasing regarding other diseases outside the gut. However, a large gap between clinical need and the lack of anti-fibrotic agents in CD remains. This paper reviews the current state of pathobiology behind fibro-stenosing CD, provides an updated diagnostic and therapeutic approach, and finally, focuses on clinical trial endpoints and possible targets of anti-fibrotic therapies.

Long-Term Outcomes of Biological Therapy in Crohn's Disease Complicated With Internal Fistulizing Disease: BIOSCOPE Study From GETECCU

INTRODUCTION

The prevalence of penetrating complications in Crohn's disease (CD) increases progressively over time, but evidence on the medical treatment in this setting is limited. The aim of this study was to evaluate the effectiveness of biologic agents in CD complicated with internal fistulizing disease.

METHODS

Adult patients with CD-related fistulae who received at least 1 biologic agent for this condition from the prospectively maintained ENEIDA registry were included. Exclusion criteria involved those receiving biologics for perianal disease, enterocutaneous, rectovaginal, anastomotic, or peristomal fistulae. The primary end point was fistula-related surgery. Predictive factors associated with surgery and fistula closure were evaluated by multivariate logistic regression and survival analyses.

RESULTS

A total of 760 patients from 53 hospitals (673 receiving anti-tumor necrosis factors, 69 ustekinumab, and 18 vedolizumab) were included. After a median follow-up of 56 months (interquartile range, 26-102 months), 240 patients required surgery, with surgery rates of 32%, 41%, and 24% among those under anti-tumor necrosis factor, vedolizumab, or ustekinumab, respectively. Fistula closure was observed in 24% of patients. Older patients, ileocolonic disease, entero-urinary fistulae, or an intestinal stricture distal to the origin of the fistula were associated with a higher risk of surgery, whereas nonsmokers and combination therapy with an immunomodulator reduced this risk.

DISCUSSION

Biologic therapy is beneficial in approximately three-quarters of patients with fistulizing CD, achieving fistula closure in 24%. However, around one-third still undergo surgery due to refractory disease. Some patient- and lesion-related factors can identify patients who will obtain more benefit from these drugs.

Co-expression of fibrotic genes in inflammatory bowel disease; A localized event?

Introduction

Extracellular matrix turnover, a ubiquitous dynamic biological process, can be diverted to fibrosis. The latter can affect the intestine as a serious complication of Inflammatory Bowel Diseases (IBD) and is resistant to current pharmacological interventions. It embosses the need for out-of-the-box approaches to identify and target molecular mechanisms of fibrosis.

Methods and results

In this study, a novel mRNA sequencing dataset of 22 pairs of intestinal biopsies from the terminal ileum (TI) and the sigmoid of 7 patients with Crohn's disease, 6 with ulcerative colitis and 9 control individuals (CI) served as a validation cohort of a core fibrotic transcriptomic signature (FIBSig), This signature, which was identified in publicly available data (839 samples from patients and healthy individuals) of 5 fibrotic disorders affecting different organs (GI tract, lung, skin, liver, kidney), encompasses 241 genes and the functional pathways which derive from their interactome. These genes were used in further bioinformatics co-expression analyses to elucidate the site-specific molecular background of intestinal fibrosis highlighting their involvement, particularly in the terminal ileum. We also confirmed different transcriptomic profiles of the sigmoid and terminal ileum in our validation cohort. Combining the results of these analyses we highlight 21 core hub genes within a larger single co-expression module, highly enriched in the terminal ileum of CD patients. Further pathway analysis revealed known and novel inflammation-regulated, fibrogenic pathways operating in the TI, such as IL-13 signaling and pyroptosis, respectively.

Discussion

These findings provide a rationale for the increased incidence of fibrosis at the terminal ileum of CD patients and highlight operating pathways in intestinal fibrosis for future evaluation with mechanistic and translational studies.

Validation of stricture length, duration and obstructive symptoms as predictors for intervention in ileal stricturing Crohn's disease

BACKGROUND

Risk factors for intervention in terminal ileal (TI) stricturing Crohn's disease (CD) are poorly defined. Novel and rigorous definitions for TI strictures recently became available.

OBJECTIVE

We aimed to describe the rates of symptoms or need for endoscopic balloon dilation (EBD) or surgery as well as risk factors of progression in a well-defined stricturing CD cohort.

METHODS

Consecutive adult patients with non-penetrating stricturing TI CD, as defined by centrally-read magnetic resonance enterography CONSTRICT criteria, were separated into a derivation and validation cohort. Clinical and imaging characteristics were collected following prespecified scoring conventions. Primary outcome was a composite endpoint of EBD or surgery ("intervention"). Multivariable analysis was performed.

RESULTS

Eighty-six patients (48.8% female, median age 36 years) met selection criteria, 17.4% had prior EBD, 59.3% previously received biologics and 58.1% of strictures were anastomotic. Median follow-up was 63.4 [95% CI: 57, 68.9] months. In the derivation cohort, at 12 and 48 months, 26% and 45% of patients had intervention, respectively. Multivariable analysis showed obstructive symptoms (Hazard ratio [HR] 1.444; 95% CI 1.126-1.852), stricture duration (HR 0.974; 95% CI, 0.954-0.995) and length (HR 1.039; 95% CI, 1.011-1.069) predicted intervention. The concordance index for split-sample validation was 0.74 and 0.67, respectively. Biologics were not associated with intervention. An online risk calculator was constructed.

CONCLUSION

In patients with TI stricturing CD, 26% and 45% required intervention at 1 and 4 years. Obstructive symptoms, stricture duration and length were independent and validated predictors of the need for intervention. These findings are important for clinical practice and aid in the design of future trials for CD strictures.

Endoscopic Balloon Dilation of Strictures: Techniques, Short- and Long-Term Outcomes, and Complications

EBD is safe and effective for the treatment of strictures. Here we describe the technique of endoscopic balloon dilation (EBD) of strictures including preprocedure considerations, indications, contraindications, and postprocedure complications. The short- and long-term outcomes of EBD including factors associated with improved outcomes are also discussed.

Multi-utility of therapeutic drug monitoring in inflammatory bowel diseases

Inflammatory bowel disease (IBD) treatment targets have progressed over time from clinical response to clinical and endoscopic remission. Several data have shown a positive correlation between serum biologic drug concentrations and favorable therapeutic outcomes. Therapeutic drug monitoring (TDM) has evolved as an important approach for optimizing the use of immunobiologics, especially antitumor necrosis factor therapy, in patients with IBD. The use of TDM is supported by medical societies and IBD experts in different contexts; however, challenges remain due to knowledge gaps that limit the widespread use of it. The aim of this review is to assess the role of TDM in IBD, focusing on the implementation of this strategy in different scenarios and demonstrating the multi-utility aspects of this approach in clinical practice.

Therapeutic Drug Monitoring of Biologics in IBD: Essentials for the Surgical Patient

Despite significant development in the pharmacological treatment of inflammatory bowel diseases (IBD) along with the evolution of therapeutic targets and treatment strategies, a significant subset of patients still requires surgery during the course of the disease. As IBD patients are frequently exposed to biologics at the time of abdominal and perianal surgery, it is crucial to identify any potential impact of biological agents in the perioperative period. Even though detectable serum concentrations of biologics do not seem to increase postoperative complications after abdominal procedures in IBD, there is increasing evidence on the role of therapeutic drug monitoring (TDM) in the perioperative setting. This review aims to provide a comprehensive summary of published studies reporting the association of drug concentrations and postoperative outcomes, postoperative recurrence (POR) after an ileocolonic resection for Crohn’s disease (CD), colectomy rates in ulcerative colitis (UC), and perianal fistulizing CD outcomes in patients treated with biologics. Current data suggest that serum concentrations of biologics are not associated with an increased risk in postoperative complications following abdominal procedures in IBD. Moreover, higher concentrations of anti-TNF agents are associated with a reduction in colectomy rates in UC. Finally, higher serum drug concentrations are associated with reduced rates of POR after ileocolonic resections and increased rates of perianal fistula healing in CD. TDM is being increasingly used to guide clinical decision making with favorable outcomes in many clinical scenarios. However, given the lack of high quality data deriving mostly from retrospective studies, the evidence supporting the systematic application of TDM in the perioperative setting is still inconclusive.

Ultrasound Elastography in the Assessment of the Intestinal Changes in Inflammatory Bowel Disease-Systematic Review

Inflammatory bowel disease (IBD) is a chronic condition affecting primarily the gastrointestinal tract and characterized by growing incidence worldwide. Complex diagnostic process of IBD as well as evaluation of disease activity and intestinal complications that are crucial for the therapeutic decisions, require repetitive, invasive, expensive, time-consuming and poorly tolerated tests. In contrast to endoscopy and computed tomography, ultrasound elastography (UE) is non-invasive, non-radiating and non-contrasting dependent tool which might be utilized in IBD patients for the assessment of the intestinal changes. Therefore, we performed the systematic review to evaluate the possible application of the ultrasound elastography for assessment of the intestinal changes in IBD. After the search of three databases: PubMed, World of Knowledge and Scopus, we identified 12 papers which were included in the final analysis. The majority of the studies were focused on the evaluation of the symptomatic ileal/ileocolonic strictures in Crohn's disease patients that required surgical resection. Only one study concerned ulcerative colitis. The authors evaluated different UE techniques: strain elastography (SE), acoustic radiation force impulse (ARFI) and shear wave elastography (SWE). Results were expressed with semi-quantitative color mapping and strain measurement. Histological scores of inflammation and fibrosis in Crohn's disease were used as a reference test in the majority of studies. Ultrasound elastography seems to be a promising novel imaging technique supporting evaluation of the intestinal strictures in Crohn's disease patients in respect to fibrosis detection as well as differentiation between fibrosis and inflammation. However, further research is needed to establish the position of ultrasound elastography in IBD management.

The role of small-bowel endoscopy in inflammatory bowel disease: an updated review on the state-of-the-art in 2021

The impact of small-bowel (SB) capsule endoscopy and device-assisted enteroscopy on clinical practice, since their introduction 2 decades ago, has been remarkable. These disruptive technologies have transformed the investigation and management of SB pathology and now have a firmly established place in guidelines and clinical algorithms. Furthermore, recent years have witnessed innovations, driven by the demand of new goals in the management of inflammatory bowel disease (IBD), such as mucosal healing and evolving strategies based on tight monitoring and accelerated escalation of care. These developments in SB endoscopy have also been paralleled by refinement in dedicated radiological SB imaging technologies. This updated review highlights the current state of the art and more recent innovations with a focus on their role in IBD.

Molecular targets and the use of biologics in the management of small bowel fibrosis in inflammatory bowel disease

PURPOSE OF REVIEW

Small bowel fibrosis is a significant burden on Crohn's disease patients with limited effective medical treatments that then requires surgery. A better understanding of the molecular mechanisms causing fibrosis and the evidence of benefit of available biologics will potentially lighten this burden and avoid the need for surgery.

RECENT FINDINGS

Transforming growth factor-beta and it's associated pathways remain the central cog in the wheel of fibrosis formation. Various new enzymes, cellular pathways, interleukins and molecules have been associated with beneficial modification of the fibrotic process. Licensed biologics such as antitumour necrosis factors continue to show evidence of efficacy in the treatment of fibrostenotic small bowel disease as well as the newer biologics ustekinumab and vedolizumab.

SUMMARY

Fibrostenotic disease of the small bowel is a significant and common debilitating complication in Crohn's disease patients. Multiple new molecular targets have been identified that may prove to become effective therapies in future. Antitumour necrosis factors remain the treatment with the best available evidence to date in fibrostenotic Crohn's disease.

Prevention and Treatment of Stricturing Crohn's Disease - Perspectives and Challenges

Introduction: Fibrostenosis is a hallmark of Crohn's disease (CD), remains a challenge in today's clinical management of inflammatory bowel disease patients and represents a key event in the disease course necessitating improved preventative strategies and a multidisciplinary approach to diagnosis and management. With the advent of anti-fibrotic therapies and well-defined clinical endpoints for stricturing CD, there is promise to impact the natural history of disease.Areas covered: This review summarizes current evidence in the natural history of stricturing Crohn's disease, discusses management approaches as well as future perspectives on intestinal fibrosis.Expert opinion: Currently, there are no specific therapies to prevent progression to fibrosis or to treat it after it becomes clinically apparent. In addition to the international effort by the Stenosis Therapy and Anti-Fibrotic Research (STAR) consortium to standardize definitions and propose endpoints in the management of stricturing CD, further research to improve our understanding of mechanisms of intestinal fibrosis will help pave the way for the development of future anti-fibrotic therapies.