In recent years, we have seen a considerable increase in the number of patients with inflammatory bowel diseases of unknown etiology, including both Crohn's disease and ulcerative colitis. Inflammatory bowel diseases can cause intestinal lesions throughout the gastrointestinal tract, necessitating gastrointestinal endoscopy for examining all relevant aspects, especially lesion characteristics, for differential diagnosis and histological diagnosis, to select the appropriate treatment options, determine treatment effectiveness, etc. Specific guidelines are necessary to ensure that endoscopy can be performed in a safe and more tailored and efficient manner, especially since gastrointestinal endoscopy, including enteroscopy, is a common procedure worldwide, including in Japan. Within this context, the Japan Gastroenterological Endoscopy Society has formulated the "Guidelines for the Endoscopic Diagnosis and Treatment of Inflammatory Bowel Diseases" to provide detailed guidelines regarding esophagogastroduodenoscopy, enteroscopy, and colonoscopy procedures for definitive diagnosis, as well as determination of treatment effectiveness in clinical cases of inflammatory bowel diseases.

Intestinal ultrasound (IU) has emerged as an alternative to detect bowel wall inflammation. The aim of this study was to compare IU findings to clinical disease, fecal calprotectin (FC), and endoscopic findings in newly diagnosed pediatric inflammatory bowel disease (IBD) patients.

This study was a 1-year, single-center, prospective study. Any pediatric patient undergoing colonoscopy could be recruited. Following ileo-colonoscopy, subjects were divided into two groups: patients diagnosed with IBD and patients without IBD. Participants had an IU within 1 month. Endoscopists and radiologists were blinded to each other. The IU findings were compared with clinical disease activity, FC, and endoscopic findings.

A total of 50 subjects were enrolled in the study; 29 (58%) were females, median age was 13.5 years, and 25 (50%) were diagnosed with IBD. IU sensitivity was 76%, specificity 84%, positive predictive value (PPV) 83%, and negative predictive value (NPV) 78%. For detection of moderate to severe disease, sensitivity, specificity, PPV, and NPV were 91.3%, 86.21%, 84%, and 92.6%, respectively. A significant correlation was noted between IU and FC, Mayo score, and Simple Endoscopic Score (0.513, 0.565, and 0.731, respectively). Pediatric Ulcerative Colitis Activity Index and Pediatric Crohn's Disease Activity Index scores had Pearson correlations of 0.070 and -0.159, respectively.

IU can be considered a screening tool for pediatric IBD. It has reasonable sensitivity, specificity, PPV, and NPV, particularly for moderate-to-severe disease. The severity noted on IU correlated with FC and endoscopic disease activity but did not correlate with clinical disease activity.

The Montreal classification has been widely used in Crohn's disease since 2005 to categorize patients by the age of onset (A), disease location (L), behavior (B), and upper gastrointestinal tract and perianal involvement. With evolving management paradigms in Crohn's disease, we aimed to assess the performance of gastroenterologists in applying the Montreal classification.

An online survey was conducted among participants at an international educational conference on inflammatory bowel diseases. Participants classified 20 theoretical Crohn's disease cases using the Montreal classification. Agreement rates with the inflammatory bowel diseases board (three expert gastroenterologists whose consensus rating was considered the gold standard) were calculated for gastroenterologist specialists and fellows/specialists with ≤ 2 years of clinical experience. A majority vote < 75% among participants was considered a notable disagreement. The same cases were classified using three large language models (LLMs), ChatGPT-4, Claude-3, and Gemini-1.5, and assessed for agreement with the board and gastroenterologists. Fleiss Kappa was used to assess within-group agreement.

Thirty-eight participants from five countries completed the survey. In defining the Montreal classification as a whole, specialists (21/38 [55%]) had a higher agreement rate with the board compared to fellows/young specialists (17/38 [45%]) (58% vs. 49%, p = 0.012) and to LLMs (58% vs. 18%, p < 0.001). Disease behavior classification was the most challenging, with 76% agreement among specialists and fellows/young specialists and 48% among LLMs compared to the inflammatory bowel diseases board. Regarding disease behavior, within-group agreement was moderate (specialists: k = 0.522, fellows/young specialists: k = 0.532, LLMs: k = 0.577; p < 0.001 for all). Notable points of disagreement included: defining disease behavior concerning obstructive symptoms, assessing disease extent via video capsule endoscopy, and evaluating treatment-related reversibility of the disease phenotype.

There is significant inter-rater disagreement in applying the Montreal classification, particularly for disease behavior in Crohn's disease. Improved education or revisions to phenotype criteria may be needed to enhance consensus on the Montreal classification.

We aimed to establish a cohort of persons with Crohn's disease (CD) enrolled from 14 Canadian centers to describe the contemporary presentation of CD in Canada.

All enrollees were at least 18 years old and underwent chart review for phenotype documentation by Montreal Classification at time of enrollment, comorbidities, inflammatory bowel disease (IBD) and other surgeries, and use IBD and other therapies.

Of 2112 adults, 59% were female, and the mean age was 44.1 (+/-14.9SD) years. The phenotype distribution was B1 = 50.4%, B2 = 22.4%, B3 = 17.3%, and missing information = 9.9%. Perineal disease was present in 14.2%. Pertaining to disease location, 35.2% of patients had disease in L1, 16.8% in L2, 48% in L3, and 0.4% in L4. There was no difference in phenotype by gender, anxiety score, depression score. Disease duration was significantly different depending on disease behavior type (B1 = 12.2 ± 10.1; B2 = 19.4 ± 12.9; B3 = 18.9 ± 11.8, P < .0001). Isolated colonic disease was much less likely to be fibrostenotic or penetrating than inflammatory disease. Penetrating disease was more likely to be associated with ileocolonic location than other locations. Perineal disease was most commonly seen in persons with B3 disease behavior (24%) than other behaviors (11% B1; 20% B2 disease, P < .0001) and more likely to be seen in ileocolonic disease (L3;19%) vs L2 (17%) and L1 (11%; P < .0001). Surgery related to IBD occurred across each behavior types at the following rates: B1 = 23%, B2 = 64%, and B3 = 74%. Inflammatory bowel disease-related surgery rates by location of disease were L1 = 48%, L2 = 21%, and L3 = 51%.

In exploring this large contemporary CD cohort we have determined that inflammatory disease is the main CD phenotype in Canada and that CD-related surgery remains very common.

Intestinal fibrosis is one of the most frequent and severe complications of Crohn's disease. Accumulating studies have reported that adipose mesenchymal stem cell-derived small extracellular vesicles (AMSC-sEVs) could alleviate renal fibrosis, hepatic fibrosis, etc., while their potential for treating intestinal fibrosis remains uncertain. Therefore, this study aims to determine the therapeutic effects of AMSC-sEVs on intestinal fibrosis and identify the mechanisms underlying these effects.

AMSC-sEVs were characterized using transmission electron microscopy, nanoparticle tracking analysis, and western blot. Whether AMSC-sEVs exert antifibrotic effects was investigated in two different murine models of intestinal fibrosis. Besides, AMSC-sEVs were co-cultured with primary human fibroblasts and CCD18co during transforming growth factor (TGF)-β1 stimulation. Label-free proteomics and rescue experiments were performed to identify candidate molecules in AMSC-sEVs. Transcriptome sequencing revealed changes in mRNA levels among different groups. Lastly, proteins related to relevant signaling pathways were identified by western blotting, and their expression and activation status were assessed.

AMSC-sEVs positively expressed CD63 and Alix and presented a classical "rim of a cup" and granule shape with approximately 43-100 nm diameter. AMSCs significantly alleviated intestinal fibrosis through secreted sEVs in vitro and in vivo. The milk fat globule-EGF factor 8 (MFGE8) was stably enriched in AMSC-sEVs and was an active compound contributing to the treatment of intestinal fibrosis by AMSCs. Mechanistically, AMSC-sEV-based therapies attenuated intestinal fibrosis by inhibiting the FAK/Akt signaling pathway.

MFGE8-containing AMSC-sEVs attenuate intestinal fibrosis, partly through FAK/Akt pathway inhibition.

More than half of patients with Crohn's disease develop intestinal fibrosis induced intestinal obstruction with debilitating symptoms throughout their disease course. The incidence of stricture formation in CD has remained unchanged over the last several decades. Factors promoting intestinal fibrosis are currently unclear, but diet may represent an underestimated risk factor for intestinal fibrosis by modification of both the host immune response and intestinal microbial composition. Evaluating the impact of diet on the course of IBD is very complex. Sarcopenia is a common problem in IBD patients and correlates with an increased rate of disease. Skeletal muscle index (SMI) is an important parameter to measure sarcopenia and is an easily accessible tool for evaluating the likelihood of complications in individuals with CD.

Using a randomized and controlled pilot design, we aimed to investigate the efficacy of 12 months of short-term dietary intervention based on essential amino acid (EAA) and sodium butyrate (NaB) supplementation in the management of stricturing Crohn's disease patients.

After the treatment in the diet EAA/NaB group, we revealed a statistically significant improvement of muscle mass (61.49 ± 5.47 vs. control 86 ± 10.70, p = 0.01) and SMI index (9.97 ± 1.79 vs. control 7.60 ± 2.29, p = 0.02). In addition, the measurement of skeletal muscle mass in CD patients has been suggested to be crucial for predicting the disease course. Indeed, after one year, surgery was required in 4/10 control group patients (40%) and 1/10 study group (10%) patients, underlining the importance of body composition alterations and adequate dietary intake in the management of these patients.

Further prospective studies are needed to confirm these results; nonetheless this nutritional approach could become an integral part in the treatment of stricturing CD patients to improve disease outcomes and increase the quality of life in these patients.

Recent genetic and transcriptomic data highlight the need for improved molecular characterisation of inflammatory bowel disease (IBD). Proteomics may advance the delineation of IBD phenotypes since it accounts for post-transcriptional modifications.

We aimed to assess the IBD spectrum based on inflammatory serum proteins and identify discriminative patterns of underlying biological subtypes across multiple European cohorts.

Using proximity extension methodology, we measured 86 inflammation-related serum proteins in 1551 IBD patients and 312 healthy controls (HC). We screened for proteins exhibiting significantly different levels among IBD subtypes and between IBD and HC. Classification models for differentiating between Crohn's disease (CD) and ulcerative colitis (UC) were employed to explore the IBD spectrum based on estimated probability scores.

Levels of multiple proteins, such as IL-17A, MMP-10, and FGF-19, differed (fold-change>1.2; FDR<0.05) between ileal vs colonic IBD. Using multivariable models, a protein signature reflecting the IBD spectrum was identified, positioning colonic CD between UC and ileal CD, which were at opposite ends of the spectrum. Based on area under the curve (AUC) estimates, classification models more accurately differentiated UC from ileal CD (median AUCs>0.73) than colonic CD (median AUCs<0.62). Models differentiating colonic CD from ileal CD demonstrated intermediate performance (median AUCs 0.67-0.69).

Our findings in serum proteins support the presence of a continuous IBD spectrum rather than a clear separation of CD and UC. Within the spectrum, disease location may reflect a more similar disease than CD vs UC, as colonic CD resembled UC more closely than ileal CD.

Luminal strictures, common in inflammatory bowel disease (IBD), especially Crohn's disease (CD), are typically treated with endoscopic balloon dilatation (EBD). The newer endoscopic stricturotomy (ESt) approach shows promise, but data is limited. This systematic review and meta-analysis assess the effectiveness and safety of ESt in IBD-related strictures.

A comprehensive literature search was conducted until November 2023 for studies assessing ESt efficacy and safety in IBD. Primary outcomes were clinical and technical success, with secondary endpoints covering adverse events, subsequent stricture surgery, additional endoscopic treatments (ESt or EBD), medication escalation, disease-related emergency department visits, and hospitalization post-ESt. Technical success was defined as passing the scope through the stricture, and clinical success was defined as symptom improvement. Single-arm meta-analysis (CMA version 3) calculated the event rate per patient with a 95% confidence interval (CI). Heterogeneity was evaluated using I2.

Nine studies were included, involving 640 ESt procedures on 287 IBD patients (169 CD, 118 ulcerative colitis). Of these, 53.3% were men, with a mean age of 43.3 ± 14.3 years and a mean stricture length of 1.68 ± 0.84 cm. The technical success rate was 96.4% (95% CI 92.5-98.3, p-value < 0.0001), and the clinical success rate was 62% (95% CI 52.2-70.9, p-value = 0.017, I2 = 34.670). The bleeding rate was 10.5% per patient, and the perforation rate was 3.5%. After an average follow-up of 0.95 ± 1.1 years, 16.4% required surgery for strictures post-ESt, while 44.2% needed additional endoscopic treatment. The medication escalation rate after ESt was 14.7%. The disease-related emergency department visit rate was 14.7%, and the disease-related hospitalization rate post-procedure was 21.3%.

Our analysis shows that ESt is safe and effective for managing IBD-related strictures, making it a valuable addition to the armamentarium of endoscopists. Formal training efforts should focus on ensuring its widespread adoption.

The incidence of inflammatory bowel disease (IBD) is rising globally. We need more tools and techniques in our armamentarium for early diagnosis, tight monitoring, and to assess disease complications of IBD. This article reviews the role of cross-sectional imaging, mainly computed tomography, MRI, and intestinal ultrasound (IUS) in IBD and its advantages, disadvantages, and limitations. While popular in other parts of the world, IUS is underutilized in the United States. It is safe, accurate, can be repeated multiple times and provides quick and actionable results in IBD care without the risk of radiation and contrast.

Patients with Crohn's disease (CD) experience disease progression over time, including strictures/stenoses, penetrating fistulae, and abscesses.

This retrospective US population-based study aimed to characterize CD progression in newly diagnosed patients.

Patient-level data from the Optum® Market Clarity database from January 1, 2016, to June 30, 2020, were used. The study comprised a 12-month baseline period (pre-diagnosis), an index date (diagnosis date), and a follow-up period. The risk of, and time to, CD progression since CD diagnosis, dispensed treatment changes following CD progression, and healthcare resource utilization before and after CD progression were assessed.

Overall, 6804 newly diagnosed patients were included. Of these, 1714 (25.2%) experienced CD progression as follows: 19.3% (1183/6117) in the first 6 months, 21.6% (1188/5503) by 1 year, 24.6% (953/3875) by 2 years, and 26.6% (444/1668) by 3 years. Intestinal obstruction/stenosis was more common than fistula or abscess. Among patients with CD progression, the median (interquartile range) estimated time to progression was 2 (0-140) days; the shortest time to progression was seen with a first intestinal obstruction/stenosis (0 [0-137] days). The frequency of several dispensed treatments increased following CD progression. Among patients who experienced progression, CD-related inpatient hospital admissions/visits increased from 436 of 1714 patients (25.4%) in the month before progression to 965 (56.3%) in the month after progression.

Over one quarter of patients with newly diagnosed CD experienced CD progression and complications within 3 years of diagnosis, highlighting the importance of monitoring for progression and early intervention to limit progression.

Stricture formation leading to obstruction in Crohn's disease (CD) remains one of the largest unmet needs in the field of inflammatory bowel diseases (IBD). Despite this need no selective anti-stricture drug has been approved for use in CD patients. This contrasts with other fibrotic diseases, such as in the lung, liver or kidney, where multiple drug development programs crossed the starting line and two anti-fibrotics are now being approved for pulmonary fibrosis. Strictures are composed of a mix of inflammation, excessive deposition of extracellular matrix (ECM) and smooth muscle hyperplasia, likely all ultimately being responsible for the luminal narrowing driving patient symptoms. Our understanding of the pathogenesis of stricturing CD has evolved and indicates a multifactorial process involving immune and non-immune cells and their soluble mediators. This understanding has rendered target pathways for anti-stricture drug development. Significant progress was made in creating consensus definitions and tools to enable clinical trials with two clinical development programs having been conceived to date. In this chapter, we discuss stricture pathogenesis with a focus on the pathways being tested in clinical trials, and clinical trial endpoints developed for this indication.

The efficacy of ustekinumab (UST) and infliximab (IFX) in Crohn's disease (CD) patients with intestinal stenosis remains uncertain.

This study aims to compare the efficacy of UST and IFX in the treatment of CD patients with intestinal stenosis.

This was a retrospective and multicenter cohort study.

In this retrospective study, we included CD patients treated with IFX or UST at five centers. We assessed the clinical response rate at weeks 12 and 24, steroid-free clinical remission rate at weeks 24 and 52 for overall patients and those with stenosis, and objective examination (intestinal ultrasound and/or endoscopy) response rate at week 52 for stenosis patients.

A total of 211 CD patients (106 IFX and 105 UST) were included, with 119 (56 IFX and 63 UST) having intestinal stenosis. In the overall patient population, there were no significant differences in clinical response rate and steroid-free clinical remission rate at weeks 12, 24, and 52 between the IFX and UST groups. In patients with stenosis, the steroid-free clinical remission rate at week 52 was significantly lower in the IFX group compared to the UST group (51.79% IFX vs 69.84% UST, p = 0.044). The objective examination response rate did not significantly differ between the IFX and UST groups at week 52 (66.67% IFX vs 76.19% UST, p = 0.690). In the UST group, steroid-free clinical remission rate was higher in bio-naïve patients than bio-experienced patients at week 24 (75.00% bio-naïve vs 55.38% bio-experienced, p = 0.043).

UST may be considered a more advantageous treatment option for those CD patients with intestinal stenosis, as it has better steroid-free clinical remission rates compared to IFX.

Incidence of obesity and Crohn's disease (CD) is increasing globally. Therefore, understanding any associations between adiposity and disease phenotype is crucial. We aimed explore the relationship between nutritional status measured by body mass index (BMI) and phenotypes of CD using a large national recallable data set.

Using National Institute for Health and Care Research-IBD Bioresource data base, we retrospectively assessed the relationship between BMI and stenosing CD by logistic regression. BMI was the primary variable of interest; CD behaviour was the dependent variable; stenosing CD was the primary outcome. Confounders were adjusted for in a multivariate model.

8797 patients diagnosed between 1942 and 2020 were included. Mean overall BMI was 26.3 kg/m2 (SD5.5). 52.7 % had a BMI ≥25 kg/m2 (mean 30.2 kg/m2, SD 4.5). Majority had inflammatory CD (62.9 %) followed by stenosing (25.1 %) and penetrating CD (12 %). Stenosing and penetrating phenotypes were more common in the <25 kg/m2 BMI group (50.7 %, 50.3 % respectively) p < 0.001. Colonic disease location was more common (27.8 % vs 24.3 %, p = 0.001) in patients with high BMI. On univariate analysis, stenosing disease was positively associated with ileal disease location, disease duration, previous surgery, use of infliximab, ustekinumab, vedolizumab, adalimumab and azathioprine but negatively associated with BMI (OR 0.98, 95%CI [0.968-0.99]). On multivariate analyses, BMI remained negatively associated with stenosing CD (OR 0.98, 95%CI [0.97-0.99]); ileal disease location (OR 3.69, 95%CI [3.22-4.24]), adalimumab (OR 1.47, 95%CI [1.30-1.66]), ustekinumab usage (OR 1.51, 95%CI [1.14-2.01] and azathioprine (OR 1.35, 95%CI [1.19-1.53]).

After multivariate analyses, BMI, ileal disease location and biologic use was negatively associated with a stenosing disease phenotype. This might reflect a change in eating behaviour due to persistent postprandial symptoms related to stenosing disease. Large longitudinal studies are needed to investigate any possible temporal relationship between the obesogenic state and intestinal fibrosis.

Transmural healing (TH) is emerging as a potential Crohn's disease (CD) treatment target. Early biological treatment seems to be associated with improved disease outcomes, but its impact on TH remains unclear. We aimed to assess the impact of early biological treatment initiation on TH and its influence on CD prognosis.

This multicenter retrospective study included adult patients with CD starting biological therapy. TH was assessed using magnetic resonance enterography (MRE) at 12 ± 6 months post-therapy initiation, with radiological examinations reviewed by blinded expert radiologists. TH was defined as complete normalization of all MRE parameters. Timing of biological therapy initiation was analyzed as a continuous variable, with optimal cutoff determined using the Youden index and clinical relevance. Logistic regression with propensity score-adjusted analysis was used to assess the association between early biological therapy initiation and TH. Long-term outcomes (bowel damage progression, CD-related surgery, CD-flare hospitalization, and therapy escalation) were evaluated.

Among 154 patients with CD, early biological therapy initiation within 12 months of diagnosis was associated with significantly higher TH rates (adjusted odds ratio [aOR], 3.23; 95% confidence interval [CI], 1.36-7.70; P < .01), which persisted after adjusting for previous biological therapy use (aOR, 2.82; 95% CI, 1.13-7.06; P = .03). Time-to-event analysis demonstrated that TH was significantly associated with reduced risk of bowel damage progression (adjusted hazard ratio [aHR], 0.28; 95% CI, 0.10-0.79; P = .02), CD-related surgery (aHR, 0.21; 95% CI, 0.05-0.88; P = .03) and therapy escalation (aHR, 0.35; 95% CI, 0.14-0.88; P = .02), independently of early biological therapy.

Early initiation of biological therapy within 12 months of diagnosis significantly increases TH rates, leading to improved long-term outcomes in patients with CD.

Background Clinical decision making and drug development for fibrostenosing Crohn disease is constrained by a lack of imaging definitions, scoring conventions, and validated end points. Purpose To assess the reliability of MR enterography features to describe Crohn disease strictures and determine correlation with stricture severity. Materials and Methods A retrospective study of patients with symptomatic terminal ileal Crohn disease strictures who underwent MR enterography at tertiary care centers (Cleveland Clinic: September 2013 to November 2020; Mayo Clinic: February 2008 to March 2019) was conducted by using convenience sampling. In the development phase, blinded and trained radiologists independently evaluated 26 MR enterography features from baseline and follow-up examinations performed more than 6 months apart, with no bowel resection performed between examinations. Follow-up examinations closest to 12 months after baseline were selected. Reliability was assessed using the intraclass correlation coefficient (ICC). In the validation phase, after five features were redefined, reliability was re-estimated in an independent convenience sample using baseline examinations. Multivariable linear regression analysis identified features with at least moderate interrater reliability (ICC ≥0.41) that were independently associated with stricture severity. Results Ninety-nine (mean age, 40 years ± 14 [SD]; 50 male) patients were included in the development group and 51 (mean age, 45 years ± 16 [SD]; 35 female) patients were included in the validation group. In the development group, nine features had at least moderate interrater reliability. One additional feature demonstrated moderate reliability in the validation group. Stricture length (ICC = 0.85 [95% CI: 0.75, 0.91] and 0.91 [95% CI: 0.75, 0.96] in development and validation phase, respectively) and maximal associated small bowel dilation (ICC = 0.74 [95% CI: 0.63, 0.80] and 0.73 [95% CI: 0.58, 0.87] in development and validation group, respectively) had the highest interrater reliability. Stricture length, maximal stricture wall thickness, and maximal associated small bowel dilation were independently (regression coefficients, 0.09-3.97; P < .001) associated with stricture severity. Conclusion MR enterography definitions and scoring conventions for reliably assessing features of Crohn disease strictures were developed and validated, and feature correlation with stricture severity was determined. © RSNA, 2024 Supplemental material is available for this article. See also the article by Rieder and Ma et al in this issue. See also the editorial by Galgano and Summerlin in this issue.

Qingchang Tongluo Decoction (QTF) is clinically used for the treatment of intestinal fibrosis in Crohn's Disease (CD). However, the role of QTF in CD-associated fibrosis and its potential pharmacological mechanism remains unclear.

The objective of this study was to elucidate the potential mechanism of QTF in treating CD-associated fibrosis, employing a combination of bioinformatics approaches - encompassing network pharmacology and molecular docking - complemented by experimental validation.

To investigate the material basis and potential protective mechanism of QTF, a network pharmacology analysis was conducted. The core components and targets of QTF underwent molecular docking analysis to corroborate the findings obtained from network pharmacology. In vitro, a colon fibrotic model was established by stimulating IEC-6 cells with 10 ng/mL of transforming growth factor(TGF-β1). In vivo, an intestinal fibrosis model was induced in BALB/c mice by TNBS. The role of QTF in inhibiting the TGF-β1/Smad signaling pathway was investigated through RT-qPCR, Western blotting, immunohistochemistry staining, and immunofluorescence staining.

Network pharmacology analysis revealed that QTF could exert its protective effect. Bioinformatics analysis suggested that Flavone and Isoflavone might be the key components of the study. Additionally, AKT1, IL-6, TNF, and VEGFA were identified as potential therapeutic targets. Furthermore, experimental validation and molecular docking were employed to corroborate the results obtained from network pharmacology. RT-qPCR, Immunofluorescence, and Western blotting results demonstrated that QTF significantly improved colon function and inhibited pathological intestinal fibrosis in vivo and in vitro.

Through the application of network pharmacology, molecular docking, and experimental validation, QTF could be confirmed to inhibit the proliferation of intestinal fibroblasts associated with CD and reduce the expression of Collagen I and VEGFA. This effect is achieved through the attenuation of ECM accumulation, primarily via the inhibition of the TGF-β1/Smad signaling pathway.

At a clinical level, ileal and colonic Crohn's disease (CD) are considered as separate entities. These subphenotypes need to be better supported by biological data to develop personalised medicine in CD. To this end, we combined different technologies (proximity extension assay, selected reaction monitoring, and high-sensitivity turbidimetric immunoassay (hsCRP)) to measure 207 immune-related serum proteins in CD patients presenting no endoscopic lesions (endoscopic remission) (n = 23), isolated ileal ulcers (n = 17), or isolated colonic ulcers (n = 16). We showed that isolated ileal ulcers and isolated colonic ulcers were specifically associated with 6 and 18 serum proteins, respectively: (high level: JUN, CNTNAP2; low level: FCRL6, LTA, CLEC4A, NTF4); (high level: hsCRP, IL6, APCS, CFB, MBL2, IL7, IL17A, CCL19, CXCL10, CSF3, IL10, CLEC4G, MMP12, VEGFA; low level: CLEC3B, GSN, TNFSF12, TPSAB1). Isolated ileal ulcers and isolated colonic ulcers were detected by hsCRP with an area under the receiver operating characteristics curve of 0.64 (p-value = 0.07) and 0.77 (p-value = 0.001), respectively. We highlighted distinct serum proteome profiles associated with ileal and colonic ulcers in CD, this finding might support the development of therapeutics and biomarkers tailored to disease location. SIGNIFICANCE: Although ileal and colonic Crohn's disease present important clinical differences (eg, progression, response to treatment and reliability of biomarkers), these two entities are managed with the same therapeutic strategy. The biological specificities of ileal and colonic Crohn's disease need to be better characterised to develop more personalised approaches. The present study used robust technologies (selected reaction monitoring, proximity extension assays and turbidimetric immunoassay) to quantify precisely 207 serum immune-related proteins in three groups of Crohn's disease patients presenting: 1) no endoscopic lesions (endoscopic remission) (n = 23); 2) isolated ileal ulcers (n = 17); 3) isolated colonic ulcers (n = 16). We found distinct serum proteome signatures associated with ileal and colonic ulcers. Our findings could foster the development of biomarkers and treatments tailored to Crohn's disease location.

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.

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.

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.

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].

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.

Operative options for duodenal Crohn's disease include bypass, stricturoplasty, or resection. What factors are associated with operation selection and whether differences exist in outcomes is unknown.

Patients with duodenal Crohn's disease requiring operative intervention across a multi-state health system were identified. Patient and operative characteristics, short-term surgical outcomes, and the need for future endoscopic or surgical management of duodenal Crohn's disease were analyzed.

40 patients underwent bypass (n = 26), stricturoplasty (n = 8), or resection (n = 6). Median age of diagnosis of Crohn's disease was 23.5 years, and over half of the patients had undergone prior surgery for CD. Operation type varied by the most proximal extent of duodenal involvement. Patients with proximal duodenal CD underwent bypass operations more commonly than those with mid- or distal duodenal disease (p = 0.03). Patients who underwent duodenal stricturoplasty more often required concomitant operations for other sites of small bowel or colonic CD (63%) compared to those who underwent bypass (39%) or resection (33%). No patients required subsequent surgery for duodenal CD at a median follow-up of 2.8 years, but two patients required endoscopic dilation (n = 1 after stricturoplasty, n = 1 after resection).

Patients who require surgery for duodenal Crohn's disease appear to have an aggressive Crohn's disease phenotype, represented by a younger age of diagnosis and a high rate of prior resection for Crohn's disease. Choice of operation varied by proximal extent of duodenal Crohn's disease.

Intestinal fibrosis resulting in stricture formation and obstruction in Crohn's disease (CD) and increased wall stiffness leading to symptoms in ulcerative colitis (UC) is among the largest unmet needs in inflammatory bowel disease (IBD). Fibrosis is caused by a multifactorial and complex process involving immune and non-immune cells, their soluble mediators and exposure to luminal contents, such as microbiota and environmental factors. To date, no antifibrotic therapy is available. Some progress has been made in creating consensus definitions and measurements to quantify stricture morphology for clinical practice and trials, but approaches to determine the degree of fibrosis within a stricture are still lacking.

We herein describe the current state of stricture pathogenesis, measuring tools and clinical trial endpoints development.

Data presented and discussed in this review derive from the past and recent literature and the authors' own research and experience.

Significant progress has been made in better understanding the pathogenesis of fibrosis, but additional studies and preclinical developments are needed to define specific therapeutic targets.

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.

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.

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.

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.

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.

Background: Crohn's disease is a chronic ailment affecting the gastrointestinal tract. Mucosal healing, a marker of reduced disease activity, is currently assessed in the colonic sections using ileocolonoscopy and magnetic resonance enteroscopy. Video capsule endoscopy (VCE) offers visualization of the entire GI mucosae. Objective: To validate a Crohn's disease model estimating the budget impact of VCE compared with the standard of care (SOC) in Italy. Methods: A patient-level, discrete-event simulation was developed to estimate the budget impact of VCE compared with SOC for Crohn's disease surveillance over 5 years in the Italian setting. Input data were sourced from a physician-initiated study from Sant'Orsola-Malpighi Hospital in Bologna, Italy, and the literature. The care pathway followed hospital clinical practice. Comparators were the current SOC (ileocolonoscopy, with or without magnetic resonance enteroscopy) and VCE. Sensitivity analysis was performed using 500-patient bootstraps. A comparative analysis regarding clinical outcomes (biologics use, surgical interventions, symptom remission) was performed to explore the validity of the model compared with real-world data. Cumulative event incidences were compared annually and semi-annually. Bayesian statistical analysis further validated the model. Results: Implementing VCE yielded an estimated €67 savings per patient per year, with savings in over 55% of patients, compared with SOC. While annual costs are higher up to the second year, VCE becomes cost saving from the third year onward. The real-world validation analysis proved a good agreement between the model and real-world patient records. The highest agreement was found for biologics, where Bayesian analysis estimated an 80.4% probability (95% CI: 72.2%-87.5%) that a decision maker would accept the result as an actual reflection of real-world data. Even where trend data diverged (eg, for surgery [43.1% likelihood of acceptance, 95% CI: 33.7%-52.8%]), the cumulative surgery count over 5 years was within the margin of error of the real-world data. Conclusions: Implementing VCE in the surveillance of patients with Crohn's disease and small bowel involvement may be cost saving in Italy. The congruence between model predictions and real-world patient records supports using this discrete-event simulation to inform healthcare decisions.

Crohn's disease (CD) is regarded as a lifelong progressive disease affecting all segments of the intestinal tract and multiple organs. Based on genome-wide association studies (GWAS) and gene expression data, transcriptome-wide association studies (TWAS) can help identify susceptibility genes associated with pathogenesis and disease behavior. In this review, we overview seven reported TWASs of CD, summarize their study designs, and discuss the key methods and steps used in TWAS, which affect the prioritization of susceptibility genes. This article summarized the screening of tissue-specific susceptibility genes for CD, and discussed the reported potential pathological mechanisms of overlapping susceptibility genes related to CD in a certain tissue type. We observed that ileal lipid-related metabolism and colonic extracellular vesicles may be involved in the pathogenesis of CD by performing GO pathway enrichment analysis for susceptibility genes. We further pointed the low reproducibility of TWAS associated with CD and discussed the reasons for these issues, strategies for solving them. In the future, more TWAS are needed to be designed into large-scale, unified cohorts, unified analysis pipelines, and fully classified databases of expression trait loci.

Patients with inflammatory bowel diseases (IBD) require proactive monitoring both during the active phase to evaluate therapeutic response and during the remission phase to evaluate relapse or colorectal cancer surveillance. However, monitoring may vary between patients with ulcerative colitis (UC) and Crohn's disease (CD), with distinct tools and intervals.

This narrative review aims to focus on modern approaches to IBD monitoring, considering international guidelines and expert consensus.

The most recent European diagnostic guidelines advocate a combination of clinical, laboratory, endoscopic, and radiological parameters to evaluate the disease course of patients with IBD. Unfortunately, the conventional symptom-based therapeutic approach does not improve long-term outcomes and there is no single ideal biomarker available. Endoscopy plays a key role in evaluating response to therapy as well as monitoring disease activity. Recently, bedside intestinal ultrasound (IUS) has gained increasing interest and diffusion as it appears to offer several advantages including the monitoring of therapeutic response.

In light of growing clinical advances, we present a schematic evidence-based monitoring algorithm that can be easily applied in clinical practice which combines all major monitoring modalities, including noninvasive tools such as IUS and video-capsule endoscopy.

The evolution of complicated pediatric Crohn's disease (CD) in the era of anti-tumor necrosis factor (aTNF) therapy continues to be described. Because CD progresses from inflammatory to stricturing (B2) and penetrating (B3) disease behaviors in a subset of patients, we aimed to understand the risk of developing complicated disease behavior or undergoing surgery in relation to aTNF timing and body mass index z-score (BMIz) normalization.

Multicenter, 5-year longitudinal data from 1075 newly diagnosed CD patients were analyzed. Descriptive statistics, univariate and stepwise multivariate Cox proportional hazard regression (CPHR), and log-rank analyses were performed for risk of surgery and complicated disease behaviors. Differential gene expression from ileal bulk RNA sequencing was correlated with outcomes.

Stricturing complications had the largest increase: from 2.98% to 10.60% over 5 years. Multivariate CPHR showed aTNF exposure within 3 months from diagnosis (hazard ratio [HR], 0.33; 95% CI, 0.15-0.71) and baseline L2 disease (HR, 0.29; 95% CI, 0.09-0.92) to be associated with reduced B1 to B2 progression. For children with a low BMIz at diagnosis (n = 294), multivariate CPHR showed BMIz normalization within 6 months of diagnosis (HR, 0.47; 95% CI, 0.26-0.85) and 5-aminosalicyclic acid exposure (HR, 0.32; 95% CI, 0.13-0.81) were associated with a decreased risk for surgery while B2 (HR, 4.20; 95% CI, 1.66-10.65) and B2+B3 (HR, 8.24; 95% CI, 1.08-62.83) at diagnosis increased surgery risk. Patients without BMIz normalization were enriched for genes in cytokine production and inflammation.

aTNF exposure up to 3 months from diagnosis may reduce B2 progression. In addition, lack of BMIz normalization within 6 months of diagnosis is associated with increased surgery risk and a proinflammatory transcriptomic profile.

Intestinal ultrasonography (US) allows for the characterization of the intestinal lesions and provides information on transmural inflammation. The aim of the study was to assess the clinical relevance of echopattern and correlation with Crohn's disease (CD) behavior and activity.

We performed a prospective study including CD patients assessed by intestinal US. The echopattern was classified as hypoechoic, hyperechoic and stratified. Color-doppler US was also performed in the thickest segment.

One hundred CD patients were enrolled. The hypoechoic echopattern was significantly correlated with penetrating behavior (r = 0.44, p<0.0001), active disease (r = 0.21, p = 0.034), C-reactive protein/Fecal Calprotectin (r = 0.31, p = 0.004; r = 0.34, p = 0.031, respectively) and steroids (r = 0.33, p = 0.0008). Hypoechoic echopattern was associated with younger age than stratified (p = 0.046) and hyperechoic (p = 0.018) echopatterns. Bowel wall thickness was greater in the hypoechoic group than in the hyperechoic/stratified groups (p = 0.011 and p<0.0001, respectively). Hypoechoic echopattern was associated with fistulas (r = 0.52, p<0.0001) and increased vascularization (r = 0.32, p = 0.001). The hyperechoic echopattern showed a significant correlation with stricturing disease and an inverse correlation with fistulas. During a follow up period of 6 months, patients with hypoechoic echopattern had an increased risk of biological therapy need or surgery.

The characterization of bowel wall echopattern allows for the identification of different CD behaviors.

Early biologic therapy within the first 18-24 months after diagnosis is associated with improved clinical outcomes in Crohn's disease [CD]. However, the definition of the best time to initiate biologic therapy remains unclear. We aimed to assess if there is an optimal timing for early biologic therapy initiation.

This was a multicentre retrospective cohort study including newly diagnosed CD patients who started anti-tumour necrosis factor [TNF] therapy within 24 months from diagnosis. The timing of initiation of biologic therapy was categorised as ≤6, 7-12, 13-18, and 19-24 months. The primary outcome was CD-related complications defined as a composite of progression of Montreal disease behaviour, CD-related hospitalisations, or CD-related intestinal surgeries. Secondary outcomes included clinical, laboratory, endoscopic, and transmural remission.

We included 141 patients where 54%, 26%, 11%, and 9% started biologic therapy at ≤6, 7-12, 13-18, and 19-24 months after diagnosis, respectively. A total of 34 patients [24%] reached the primary outcome: 8% had progression of disease behaviour, 15% were hospitalised, and 9% required surgery. There was no difference in the time to a CD-related complication according to the time of initiation of biologic therapy within the first 24 months. Clinical, endoscopic, and transmural remission was achieved in 85%, 50%, and 29%, respectively, but no differences were found according to the time of initiation of biologic therapy.

Starting anti-TNF therapy within the first 24 months after diagnosis was associated with a low rate of CD-related complications and high rates of clinical and endoscopic remission, although we found no differences with earlier initiation within this window of opportunity.

Background: There is limited real-world evidence on treatment patterns of patients with Crohn's disease (CD) initiating biologics with an extensive follow-up period. This study describes persistence and dose titration among CD patients with 3 years of follow-up. Methods: This retrospective observational study was conducted using the STATinMED RWD Insights all-payer medical and pharmacy data. Adult patients with at least 1 CD medical claim and at least 1 medical/pharmacy claim for a biologic (adalimumab [ADA], certolizumab pegol (CZP), infliximab [IFX] and its biosimilar products [IFX-BS], ustekinumab [UST], and vedolizumab [VDZ]) between September 2016 and October 2018 were identified. Commercially insured patients with continuous capture for at least 12 months before and at least 36 months after biologics initiation were selected. Confirmed CD patients were included in the final cohort. Baseline patient characteristics and treatment patterns over the 3-year follow-up period were evaluated. Results were summarized using means and SD or counts and percentages. Results: A total of 2309 confirmed patients with CD were identified (847 [36.7%] IFX, 534 [23.1%] ADA, 486 [21.1%] VDZ, 394 [17.1%] UST, 85 [3.7%] CZP, and 72 [3.1%] IFX-BS). CZP and IFX-BS were excluded due to small sample sizes. Approximately half of CD patients were between ages 35 and 54. Patients on UST had a higher Charlson Comorbidity Index score. Common comorbidities (>10%) included anemia, anxiety, depression, and hypertension. Persistence over 3 years' follow-up was highest for UST (61.4%) patients, followed by VDZ (58.0% ), ADA (52.1% , and IFX (48.1%). The discontinuation rate without switch or restart was highest for ADA (37.3%), followed by UST (30.7%), IFX (28.1%), and VDZ (25.3%). Over the 3 years of follow-up, the dose titration rate was highest for IFX (76.5%) and lowest for UST (50.8%). In particular, UST had the lowest dose escalation rate (35.5%) and highest dose-reduction rate (16.5%). Conclusions: Patients with CD on UST had the highest persistence and lowest dose escalation across different biologic users over the 3-year follow-up period, possibly suggesting a better clinical response of UST. Future studies with longer follow-up adjusting for confounders are needed to better understand treatment patterns among biologics users.

Crohn's disease (CD) is a type of inflammatory bowel disease. The number of IBD cases worldwide was estimated to be 4.9 million in 2019. CD exhibits heterogeneity in clinical presentation, anatomical involvement, disease behaviour, clinical course and response to treatment. The classical description of CD involves transmural inflammation with skip lesions anywhere along the entire gastrointestinal tract. The complexity and heterogeneity of Crohn's disease is not currently reflected in the conventional classification system. Though the knowledge of Crohn's pathophysiology remains far from understood, the established complex interplay of the omics-genomics, transcriptomics, proteomics, epigenomics, metagenomics, metabolomics, lipidomics and immunophenomics-provides numerous targets for potential molecular markers of disease. Advancing technology has enabled identification of small molecules within these omics, which can be extrapolated to differentiate types of Crohn's disease. The multi-omic future of Crohn's disease is promising, with potential for advancements in understanding of its pathogenesis and implementation of personalised medicine.

The objective of this study was to estimate the effectiveness of early biologics compared to conventional treatment in the management of Crohn's disease among pediatric and adolescent patients.

A comprehensive literature search was conducted in four electronic databases to identify relevant studies published from inception to 2023. The inclusion criteria comprised randomized controlled trials (RCTs) and cohort studies that reported on the efficacy and clinical outcomes of early biologic therapy compared to late/conventional therapy in children with Crohn's disease. The quality of the studies was assessed using the Cochrane Risk of Bias tool and the Newcastle Ottawa scale.

A total of 13 studies (2 RCTs and 11 cohort studies), involving 861 patients, were included in the meta-analysis. The results demonstrated that early biologic therapy was associated with a significantly higher rate of clinical remission (risk ratio [RR] 1.30, 95% confidence interval [CI] 1.10-1.54), lower relapse rates (RR 0.33, 95% CI 0.21-0.53), and improved mucosal healing (RR 1.47, 95% CI 1.10-1.97) compared to late/conventional therapy. However, it should be noted that there was evidence of publication bias among studies reporting clinical remission.

In conclusion, early biologic therapy is significantly more effective in achieving clinical remission (within two years of diagnosis), promoting mucosal healing, and reducing relapse rates in pediatric and adolescent patients with Crohn's disease, compared to late/conventional therapy. These findings emphasize the importance of initiating biological therapy early in the treatment of Crohn's disease in this patient population.