Crohn's disease associated strictures

Invasive Therapeutic Strategies for Stricturing Crohn's Disease in Childhood: A Systematic Review and Meta-Analysis

BACKGROUND

Crohn's disease (CD) is a chronic inflammatory condition of the gastrointestinal tract. Current drugs are not effective for treating the primary fibrotic component of CD. Recommended invasive treatments include endoscopic balloon dilation, surgery with resection, or strictureplasty. This meta-analysis compared invasive treatment techniques for CD-related strictures in the pediatric population.

METHODS

The MEDLINE, EMBASE, and LILACS databases were searched from inception to December 2023. This meta-analysis was performed as per the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The outcome was measured by the rate of stenosis recurrence and the adverse events of the techniques. Eligibility criteria were studies that involved the analysis of the recurrence rate of stenosis in pediatric patients with CD requiring surgical intervention after undergoing any of the previously proposed therapies. Additionally, adverse events were analyzed.

RESULTS

Three studies comprising a total of 106 endoscopic balloon dilations demonstrated a combined rate of stricture recurrence in patients with CD requiring surgical intervention of 0.171 (95% confidence interval [CI], 0.110-0.255). Three studies comprising a total of 49 surgical resections demonstrated a pooled event rate of 0.100 (95% CI, 0.038-0.240). Finally, 2 studies comprising a total of 38 strictureplasties demonstrated a pooled event rate of 0.347 (95% CI, 0.070-0.789). Concerning adverse events, the most common occurrences were found after surgical resection.

CONCLUSIONS

Surgical resection is the best option for treating strictures in pediatric CD patients in terms of recurrence rate, compared with endoscopic balloon dilation and strictureplasty. Nevertheless, surgical resection is associated with more adverse events.

Radiology of fibrosis part II: abdominal organs

Fibrosis is the aberrant process of connective tissue deposition from abnormal tissue repair in response to sustained tissue injury caused by hypoxia, infection, or physical damage. It can affect almost all organs in the body causing dysfunction and ultimate organ failure. Tissue fibrosis also plays a vital role in carcinogenesis and cancer progression. The early and accurate diagnosis of organ fibrosis along with adequate surveillance are helpful to implement early disease-modifying interventions, important to reduce mortality and improve quality of life. While extensive research has already been carried out on the topic, a thorough understanding of how this relationship reveals itself using modern imaging techniques has yet to be established. This work outlines the ways in which fibrosis shows up in abdominal organs and has listed the most relevant imaging technologies employed for its detection. New imaging technologies and developments are discussed along with their promising applications in the early detection of organ fibrosis.

Dihydromyricetin alleviates inflammatory bowel disease associated intestinal fibrosis by inducing autophagy through the PI3K/AKT/mTOR signaling pathway

Intestinal fibrosis is a common complication of inflammatory bowel disease and is characterized by tissue stiffening and luminal narrowing. Dihydromyricetin (DHM) can alleviate liver fibrosis and renal interstitial fibrosis by inducing autophagy. However, whether DHM can alleviate intestinal fibrosis remains unclear. This study is aimed at evaluating the role and mechanism of action of DHM in inflammatory bowel disease-associated intestinal fibrosis. Mice were administered dextran sulfate sodium (DSS) in drinking water to induce inflammatory bowel disease-associated intestinal fibrosis. HE staining, qPCR, and Western blotting were used to analyze colon inflammation. Masson's trichrome staining, qPCR, Western blotting, and immunofluorescence staining were used to evaluate the severity of fibrosis. Transmission electron microscopy and Western blotting were used to assess the activation of autophagosomes. The human colonic fibroblast line CCD-18Co was cultured in the presence of TGF-β1 to develop a fibrotic phenotype. Immunofluorescence staining, Western blotting, and qPCR were used to assess the alteration of fibrosis markers and used to investigate whether DHM-induced autophagy was involved in the inactivation of CCD-18Co cells. Additionally, the role of the PI3K/AKT/mTOR pathway was investigated. DHM alleviated intestinal inflammation and inhibited the progression of intestinal fibrosis. Additionally, DHM induced the activation of autophagy, thereby alleviating intestinal fibrosis, and downregulated the PI3K/AKT/mTOR signaling pathway in vitro. Overall, this study demonstrated that DHM can inhibit the progression of intestinal fibrosis and activation of colonic fibroblasts by inducing autophagy through the PI3K/AKT/mTOR signaling pathway, thereby playing a preventive and therapeutic role in intestinal fibrosis.

Single cell sequencing data identify distinct B cell and fibroblast populations in stricturing Crohn's disease

Single cell RNA sequencing of human full thickness Crohn's disease (CD) small bowel resection specimens was used to identify potential therapeutic targets for stricturing (S) CD. Using an unbiased approach, 16 cell lineages were assigned within 14,539 sequenced cells from patient-matched SCD and non-stricturing (NSCD) preparations. SCD and NSCD contained identical cell types. Amongst immune cells, B cells and plasma cells were selectively increased in SCD samples. B cell subsets suggested formation of tertiary lymphoid tissue in SCD and compared with NSCD there was an increase in IgG, and a decrease in IgA plasma cells, consistent with their potential role in CD fibrosis. Two Lumican-positive fibroblast subtypes were identified and subclassified based on expression of selectively enriched genes as fibroblast clusters (C) 12 and C9. Cells within these clusters expressed the profibrotic genes Decorin (C12) and JUN (C9). C9 cells expressed ACTA2; ECM genes COL4A1, COL4A2, COL15A1, COL6A3, COL18A1 and ADAMDEC1; LAMB1 and GREM1. GO and KEGG Biological terms showed extracellular matrix and stricture organization associated with C12 and C9, and regulation of WNT pathway genes with C9. Trajectory and differential gene analysis of C12 and C9 identified four sub-clusters. Intra sub-cluster gene analysis detected 13 co-regulated gene modules that aligned along predicted pseudotime trajectories. CXCL14 and ADAMDEC1 were key markers in module 1. Our findings support further investigation of fibroblast heterogeneity and interactions with local and circulating immune cells at earlier time points in fibrosis progression. Breaking these interactions by targeting one or other population may improve therapeutic management for SCD.

LncRNA MSC-AS1 regulates SNIP1 SUMOylation-mediated EMT by binding to SENP1 to promote intestinal fibrosis in Crohn's disease

As a common complication of Crohn's disease (CD), the mechanism underlying CD intestinal fibrosis remains unclear. Studies have shown that epithelial-mesenchymal transition (EMT) is a key step in the development of intestinal fibrosis in CD. It is currently known that the long non-coding RNA (lncRNA) MSC-AS1 plays an important role in regulating the secretion of inflammatory mediators and EMT; however, its role in intestinal fibrosis remains unclear. MSC-AS1 was significantly upregulated in the CD intestinal tissue and intestinal tissue of mice treated with 2,4,6-trinitrobenzenesulfonic acid. Downregulation of its expression can inhibit EMT and alleviates intestinal fibrosis by regulating SNIP1. In addition, MSC-AS1 directly interacted with SENP1, blocking the deSUMOylation of SNIP1 and inhibiting its activity. Furthermore, we found that SENP1 enhanced the expression of SNIP1 and reduced intestinal fibrosis. In summary, MSC-AS1 regulates EMT through the SENP1/SNIP1 axis to promote fibrosis, and may be considered a potential molecular target for the treatment of CD and intestinal fibrosis.

Efficacy of exclusive enteral nutrition on the mucosal healing of different gastrointestinal segments in children with Crohn's disease

OBJECTIVE

To investigate the association between disease location and segmental mucosal healing (SMH) following exclusive enteral nutrition (EEN) in children with Crohn's disease (CD).

METHODS

Treatment-naive pediatric patients with endoscopically active CD treated with EEN alone as induction therapy were retrospectively enrolled from January 1, 2017 to June 30, 2022. The simple endoscopic score for CD (SES-CD) was employed to score disease activity in the upper gastrointestinal (GI) tract (esophagus, stomach, duodenum), rectum, left colon, transverse colon, right colon, and terminal ileum. While the Lewis score assessed that of the small bowel from the jejunum to the proximal ileum (except the terminal ileum). The variation in the total scores for each segment and SES-CD subscores for each ileocolonic segment from baseline to 1 year after EEN therapy and the segmental endoscopic outcomes and potential predictors associated with SMH for the segments scored by SES-CD were evaluated.

RESULTS

Overall, 82 children with CD were enrolled. Except for the upper GI segment, scores in other segments declined significantly from baseline to EEN completion (all P < 0.001). We analyzed 486 segments (79, 80, 81, 82, 82 and 82 from upper GI tract, terminal ileum, right colon, transverse colon, left colon, and rectum) and found that the segmental SES-CD at baseline (odds ratio [OR] 0.62, 95% confidence interval [CI] 0.55-0.70, P < 0.001) and upper GI location (OR 0.25, 95% CI 0.11-0.55, P = 0.001) were associated with SMH at EEN completion.

CONCLUSION

Disease location of the upper GI segment in pediatric CD was associated with SMH following EEN therapy.

Bridging autoimmunity and epigenetics: The influence of lncRNA MALAT1

Autoimmune disorders represent a heterogeneous spectrum of conditions defined by an immune system's atypical reactivity against endogenous constituents. In the complex anatomy of autoimmune pathogenesis, lncRNAs have appeared as pivotal arbiters orchestrating the mechanisms of ailment initiation, immune cascades, and transcriptional modulation. One such lncRNA, MALAT1, has garnered attention for its potential association with the aetiology of several autoimmune diseases. MALAT1 has been shown to influence a wide spectrum of cellular processes, which include cell multiplication and specialization, as well as apoptosis and inflammation. In autoimmune diseases, MALAT1 exhibits both disease-specific and shared patterns of dysregulation, often correlating with disease severity. The molecular mechanisms underlying MALAT1's impact on autoimmune disorders include epigenetic modifications, alternative splicing, and modulation of gene expression networks. Additionally, MALAT1's intricate interactions with microRNAs, other lncRNAs, and protein-coding genes further underscore its role in immune regulation and autoimmune disease progression. Understanding the contribution of MALAT1 in autoimmune pathogenesis across different diseases could offer valuable insights into shared pathways, thereby clearing a path for the creation of innovative and enhanced therapeutic approaches to address these complex disorders. This review aims to elucidate the complex role of MALAT1 in autoimmune disorders, encompassing rheumatoid arthritis, multiple sclerosis, inflammatory bowel disease (Crohn's disease and ulcerative colitis), type 1 diabetes, systemic lupus erythematosus, and psoriasis. Furthermore, it discusses the potential of MALAT1 as a diagnostic biomarker, therapeutic target, and prognostic indicator.

Comprehensive review and update of stricturing Crohn's disease

Up to 50% of patients with Crohn's disease develop a stricture within 10 years of diagnosis. Crohn's strictures can compose of inflammation, fibrosis or smooth muscle expansion and usually a combination of these. There have been numerous new developments in imaging modalities in determining the composition of Crohn's strictures. Magnetic resonance imaging remains the best upfront imaging modality to characterize Crohn's strictures. Gastrointestinal ultrasound (GIUS) has an increasing role in clinical practice, particularly for monitoring stricture response as a treat-to-target tool. Novel imaging techniques to differentiate between fibrosis and inflammatory strictures have been developed including contrast-enhanced GIUS, strain or shear wave elastography with GIUS and multiple new magnetic resonance imaging (MRI) protocols, including diffusion weighted, delayed contrast enhancement and magnetization transfer MR protocols. However, these techniques require further validation and standardization. Regarding therapeutics, anti-tumor necrosis agents with a treat-to-target strategy have the highest quality evidence in treating strictures and can lead to stricture regression in some cases. Endoscopic balloon dilatation remains a mainstay in the treatment algorithm of treating predominantly fibrostenotic Crohn's strictures, particularly those which are symptomatic, < 5 cm in length and not causing prestenotic dilatation. Endoscopic balloon dilatation has greater effectiveness in anastomotic strictures. Surgery remains an important treatment option in Crohn's strictures, with segmental resection and stricturoplasty having their own advantages and disadvantages. Kono-S anastomosis may be superior to conventional anastomosis for endoscopic recurrence; however, further high-quality studies are required to confirm this. Using risk stratification models such as the BACARDI risk model is important to guide management decisions between a medical and surgical approach. Early post-operative medical prophylaxis with an advanced therapy is an important consideration to prevent disease recurrence. This review expands on the above topics, highlights research gaps and provides a suggested investigation and management pathway in stricturing Crohn's disease.

Stromal Cell Regulation of Intestinal Inflammatory Fibrosis

Intestinal inflammatory fibrosis is a severe consequence of inflammatory bowel diseases (IBDs). There is currently no cure for the treatment of intestinal fibrosis in IBD. Although inflammation is necessary for triggering fibrosis, the anti-inflammatory agents used to treat IBD are ineffective in preventing the progression of intestinal fibrosis and stricture formation once initiated, suggesting that inflammatory signals are not the sole drivers of fibrosis progression once it is established. Among multiple mechanisms involved in the initiation and progression of intestinal fibrosis in IBD, stromal cells play critical roles in mediating the process. In this review, we summarize recent progress on how stromal cells regulate intestinal fibrosis in IBD and how they are regulated by focusing on immune regulation and gut microbiota. We also outline the challenges moving forward in the field.

Sinapic Acid Attenuates Chronic DSS-Induced Intestinal Fibrosis in C57BL/6J Mice by Modulating NLRP3 Inflammasome Activation and the Autophagy Pathway

Ulcerative colitis (UC) is a chronic gastrointestinal disease that results from repeated inflammation and serious complications. Sinapic acid (SA) is a hydroxycinnamic acid present in a variety of plants that has antioxidant, anti-inflammatory, anticancer, and other protective effects. This study investigated the antifibrotic effect of SA on chronic colitis induced by dextran sulfate sodium salt (DSS) in mice. We observed that SA could significantly reduce clinical symptoms (such as improved body weight loss, increased colon length, and decreased disease activity index score) and pathological changes in mice with chronic colitis. SA supplementation has been demonstrated to repair intestinal mucosal barrier function and maintain epithelial homeostasis by inhibiting activation of the NLRP3 inflammasome and decreasing the expression of IL-6, TNF-α, IL-17A, IL-18, and IL-1β. Furthermore, SA could induce the expression of antioxidant enzymes (Cat, Sod1, Sod2, Mgst1) by activating the Nrf2/keap1 pathway, thus improving antioxidant capacity. Additionally, SA could increase the protein expression of downstream LC3-II/LC3-I and Beclin1 and induce autophagy by regulating the AMPK-Akt/mTOR signaling pathway, thereby reducing the production of intestinal fibrosis-associated proteins Collagen-I and α-SMA. These findings suggest that SA can enhance intestinal antioxidant enzymes, reduce oxidative stress, expedite intestinal epithelial repair, and promote autophagy, thereby ameliorating DSS-induced colitis and intestinal fibrosis.

A comprehensive metabolite fingerprint of fibrostenosis in patients with Crohn's disease

Intestinal fibrostenosis in patients with Crohn's disease (CD) is a common and untreatable comorbidity that is notoriously difficult to monitor. We aimed to find metabolites associated with the presence of fibrostenosis in patients with CD using targeted and untargeted metabolomics analyses of serum and primary cell cultures using hyphenated ultra-high performance liquid chromatography high-resolution mass spectrometry. Targeted metabolomics revealed 11 discriminating metabolites in serum, which were enriched within the arginine and proline metabolism pathway. Based on untargeted metabolomics and discriminant analysis, 166 components showed a high predictive value. In addition, human intestinal fibroblasts isolated from stenotic tissue were characterized by differential levels of medium-chain dicarboxylic acids, which are proposed as an energy source through beta-oxidation, when oxidative phosphorylation is insufficient. Another energy providing pathway in such situations is anaerobic glycolysis, a theory supported by increased expression of hexokinase 2 and solute carrier family 16 member 1 in stenotic fibroblasts. Of interest, four (unannotated) metabolic components showed a negative correlation with hexokinase 2 gene expression. Together, this study provides a discriminative metabolic fingerprint in the serum and in intestinal fibroblasts of stenotic and non-stenotic patients with CD suggestive for increased production of building blocks for collagen synthesis and increased glycolysis.

Anastomotic Configuration and Temporary Diverting Ileostomy Do Not Increase Risk of Anastomotic Stricture in Postoperative Crohn's Disease

INTRODUCTION

Surgical management of Crohn's disease (CD) is common. Postoperative complications include anastomotic stricturing (AS). The natural history and risk factors for AS have not been elucidated.

METHODS

A retrospective cohort study of patients with CD who underwent ileocolonic resection (ICR) with ≥1 postoperative ileocolonoscopy between 2009 and 2020. Postoperative ileocolonoscopies with corresponding cross-sectional imaging were evaluated for evidence of AS without neoterminal ileal extension. Severity of AS and endoscopic intervention at time of detection were collected. Primary outcome was development of AS. Secondary outcome was time to AS detection.

RESULTS

A total of 602 adult patients with CD underwent ICR with postoperative ileocolonoscopy. Of these, 426 had primary anastomosis, and 136 had temporary diversion at time of ICR. Anastomotic configuration consisted of 308 side-to-side, 148 end-to-side, and 136 end-to-end. One hundred ten (18.3%) patients developed AS with median time of 3.2 years to AS detection. AS severity at time of detection was associated with need for repeat surgical resection for AS. On multivariable Cox proportional hazard regression, anastomotic configuration and temporary diversion were not associated with risk of or time to AS. Preoperative stricturing disease was associated with decreased time to AS (adjusted hazard ratio 1.8; P = 0.049). Endoscopic ileal recurrence before AS was not associated with subsequent AS detection.

DISCUSSION

AS is a relatively common postoperative CD complication. Patients with previous stricturing disease behavior are at increased risk of AS. Anastomotic configuration, temporary diversion, and ileal CD recurrence do not increase risk of AS. Early detection and intervention for AS may help prevent progression to repeat ICR.

Imaging of Strictures in Crohn's Disease

Crohn's disease (CD) is a chronic inflammation of the digestive tract, and it frequently affects young patients. It can involve any intestinal segment, even though it frequently affects the distal ileum. Up to 80% of patients with CD present with inflammatory behavior, and 5% to 28% develop stricturing disease. Based on the predominant mechanism causing them, strictures can be categorized as inflammatory, fibrotic, or mixed. Determining the relative amounts of inflammation and fibrosis in a stricture can influence treatment decisions. Imaging is an extremely useful tool in patients with small bowel stricturing CD to confirm the diagnosis and to evaluate disease characteristics, usually using CT or MRI. The aim of this paper is to describe how imaging can evaluate a patient with small bowel CD stricture.

Downregulation of Heat Shock Protein 72 Contributes to Fibrostenosis in Crohn's Disease

Background/Aims

Crohn's disease (CD) with recurrent inflammation can cause intestinal fibrostenosis due to dysregulated deposition of extracellular matrix. However, little is known about the pathogenesis of fibrostenosis. Here, we performed a differential proteomic analysis between normal, inflamed, and fibrostenotic specimens of patients with CD and investigated the roles of the candidate proteins in myofibroblast activation and fibrosis.

Methods

We performed two-dimensional difference gel electrophoresis and identified candidate proteins using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and orbitrap liquid chromatography-mass spectrometry. We also verified the levels of candidate proteins in clinical specimens and examined their effects on 18Co myofibroblasts and Caco-2 intestinal epithelial cells.

Results

We identified five of 30 proteins (HSP72, HSPA5, KRT8, PEPCK-M, and FABP6) differentially expressed in fibrostenotic CD. Among these proteins, the knockdown of heat shock protein 72 (HSP72) promoted the activation and wound healing of myofibroblasts. Moreover, knockdown of HSP72 induced the epithelial-mesenchymal transition of intestinal epithelial cells by reducing E-cadherin and inducing fibronectin and α-smooth muscle actin, which contribute to fibrosis.

Conclusions

HSP72 is an important mediator that regulates myofibroblasts and epithelial-mesenchymal transition in fibrosis of CD, suggesting that HSP72 can serve as a target for antifibrotic therapy.

Crohn's disease: an update

Crohn's disease (CD) is a chronic, relapsing and remitting inflammatory bowel disease (IBD) that is increasing in incidence and prevalence globally. Management aims to achieve endoscopic healing, symptom resolution and improvement in quality of life. Therapeutic approaches in CD vary depending on disease phenotype. Thiopurines are important in steroid-sparing maintenance therapy, while anti-tumour necrosis factor agents play a fundamental role, especially in fistulising CD. Suboptimal response to these medications may require escalation to other immunosuppressive and biologic therapies, and surgical intervention is still required in a proportion of patients. Tailoring treatment to target specific patient phenotypes, disease severity and patient wishes is becoming more feasible with the growing array of therapeutic options in CD.

High-Density IgG4+ Plasma Cells Infiltration Is Associated With Fibroplasia in Fibrostenotic Crohn's Disease

Transmural fibrosis and stricture formation are key pathogenic processes for Crohn's disease that underlies clinical refractoriness, resulting in severe morbidity. The mechanisms for fibroplasia in Crohn's are not fully elucidated. In this study, we identified a cohort of refractory Crohn's disease with surgically resected bowel specimens including cases with bowel stricture and age-/sex-matched refractory disease without bowel stricture. Via immunohistochemistry, density and distribution of IgG4+ plasma cells in resected cases were analyzed. The histologic severity of fibrosis and association with gross evidence of stricture formation and IgG4+ plasma cells were comprehensively analyzed. Our results showed that density of IgG4+ plasma cells/high-power field (IgG4+ PCs/HPF) was significantly associated with increasing histologic fibrosis score (15 IgG4+ PCs/HPF in specimens with fibrosis score 0 vs 31 IgG4+ PC/HPF in fibrosis score 2 and 3, P = .039). Patients with gross evidence of stricture had significantly higher fibrosis scores compared to those without gross evidence of stricture (P = .044). There was a trend that mean IgG4+ plasma cell count was higher in Crohn's disease with gross stricture formation (P = .26), although it did not reach statistical significance (likely due to multiple pathogenesis events involved in bowel stricture formation besides IgG4+ plasma cells; such as transmural fibrosis, muscular hypertrophy, transmural ulcer/scar formation, and muscular-neural dysfunction). Our findings indicate IgG4+ plasma cells are associated with increasing histologic fibrosis in Crohn's. Further research is needed to establish a role for IgG4+ plasma cells in fibroplasia with an eye toward potential medical therapies targeting IgG4+ plasma cells to prevent transmural fibrosis.

Exosomal miR-103a-3p from Crohn's Creeping Fat-Derived Adipose-Derived Stem Cells Contributes to Intestinal Fibrosis by Targeting TGFBR3 and Activating Fibroblasts

BACKGROUND AND AIMS

Mesenteric adipose tissue hypertrophy is a hallmark of Crohn's disease [CD], and creeping fat [CF] is unique to CD. Adipose-derived stem cells [ASCs] from inflammatory tissue exhibited altered biological functions. The role of ASCs isolated from CF in intestinal fibrosis and the potential mechanism remain unclear.

METHODS

ASCs were isolated from CF [CF-ASCs] and disease-unaffected mesenteric adipose tissue [Ctrl-ASCs] of patients with CD. A series of in vitro and in vivo experiments were conducted to study the effects of exosomes from CF-ASCs [CF-Exos] on intestinal fibrosis and fibroblast activation. A micro-RNA microarray analysis was performed. Western blot, luciferase assay and immunofluorescence were performed to further detect the underlying mechanisms.

RESULTS

The results indicated that CF-Exos promoted intestinal fibrosis by activating fibroblasts in a dose-dependent manner. They continuously promoted progression of intestinal fibrosis even after dextran sulphate sodium withdrawal. Further analysis showed that exosomal miR-103a-3p was enriched in CF-Exos and participated in exosome-mediated fibroblast activation. TGFBR3 was identified as a target gene of miR-103a-3p. Mechanistically, CF-ASCs released exosomal miR-103a-3p and promoted fibroblast activation by targeting TGFBR3 and promoting Smad2/3 phosphorylation. We also found that the expression of miR-103a-3p in diseased intestine was positively associated with the degree of CF and fibrosis score.

CONCLUSION

Our findings show that exosomal miR-103a-3p from CF-ASCs promotes intestinal fibrosis by activating fibroblasts via TGFBR3 targeting, suggesting that CF-ASCs are potential therapeutic targets for intestinal fibrosis in CD.

Surgical management of duodenal Crohn's disease

BACKGROUND

The case of Crohn's disease involving the duodenum is rare, and its surgical management requires a thorough understanding.

AIM

To investigate the surgical management of duodenal Crohn’s disease.

METHODS

We systematically reviewed patients diagnosed with duodenal Crohn's disease who underwent surgery in the Department of Geriatrics Surgery of the Second Xiangya Hospital of Central South University from January 1, 2004, to August 31, 2022. The general information, surgical procedures, prognosis, and other information of these patients were collected and summarized.

RESULTS

A total of 16 patients were diagnosed with duodenal Crohn’s disease, where 6 cases had primary duodenal Crohn’s disease, and 10 had secondary duodenal Crohn’s disease. Among patients with primary disease, 5 underwent duodenal bypass and gastrojejunostomy, and 1 received pancreaticoduodenectomy. Among those with a secondary disease, 6 underwent closure of duodenal defect and colectomy, 3 received duodenal lesion exclusion and right hemicolectomy, and 1 underwent duodenal lesion exclusion and double-lumen ileostomy.

CONCLUSION

Crohn's disease involving the duodenum is a rare condition. Different surgical management should be applied for patients with Crohn's disease presenting with different clinical manifestations.

The Promise of Single-Cell RNA Sequencing to Redefine the Understanding of Crohn's Disease Fibrosis Mechanisms

Crohn's disease (CD) is a chronic inflammatory bowel disease with a high prevalence throughout the world. The development of Crohn's-related fibrosis, which leads to strictures in the gastrointestinal tract, presents a particular challenge and is associated with significant morbidity. There are currently no specific anti-fibrotic therapies available, and so treatment is aimed at managing the stricturing complications of fibrosis once it is established. This often requires invasive and repeated endoscopic or surgical intervention. The advent of single-cell sequencing has led to significant advances in our understanding of CD at a cellular level, and this has presented opportunities to develop new therapeutic agents with the aim of preventing or reversing fibrosis. In this paper, we discuss the current understanding of CD fibrosis pathogenesis, summarise current management strategies, and present the promise of single-cell sequencing as a tool for the development of effective anti-fibrotic therapies.

Causal Relationship between Physiological and Pathological Processes in the Brain and in the Gastrointestinal Tract: The Brain-Intestine Axis

The brain and gastrointestinal tract are the most important organs responsible for detecting, transmitting, integrating, and responding to signals coming from the internal and external environment. A bidirectional system of neurohumoral communication (the "intestine-brain" axis) combines the activity of the intestine and brain (or brain and intestine) of a person. It affects human development and behavior. This paper analyzes the literature data on the existence of a relationship between the central and enteral nervous systems. Based on data on the number of neurons in the enteral nervous system (approximately 250 million nerve cells), the concept of a "second brain" in the intestine has been proposed in foreign literature, which, by its influence on the brain, can have a more powerful influence than the spinal cord (approximately 10 million neurons) with its autonomic nervous system. However, it turned out that Russian scientists, academicians of the Academy of Sciences of the Soviet Union I.P. Pavlov, K.M. Bykov, and A.M. Ugolev, analyzed cortical-visceral relationships in the 20th century and wrote about the existence of a connection between the central and enteral nervous systems. One of the urgent problems of modern physiology, pathophysiology, biophysics, biochemistry, and medicine is to clarify the causal relationship between the central and enteral nervous systems, as well as between neurological, mental, and gastrointestinal diseases in order to combine the efforts of specialists of various medical and biological profiles to solve urgent medical problems.

Factors affecting the development of complications in Crohn's disease in patients undergoing intestinal resection

Surgery is a common form of management for Crohn disease (CD) in the presence of intra-abdominal complications. In this study, we investigated the effect of various factors on the development of postoperative complications in patients who underwent surgery for complicated CD. Patients who underwent surgery between 2011 and 2018 were included in this study. Information on age, sex, presence of extraintestinal findings, operation indications, operation type, and postoperative complications was obtained. Groups with and without postoperative complications were compared according to body mass index, American Society of Anesthesiologists score, comorbidities, smoking status, preoperative drug use, presence of perianal disease, presence of a stoma, synchronous small intestine resection surgery, duration of hospital stay, and preoperative biochemical parameters. A total of 192 patients were included, of which 53.1% were female and 46.9% were male. Patients were indicated for surgery for reasons such as stricture, abscess, fistula, and tumor development. As the surgical method, patients were operated on by open or laparoscopic method (86% and 14%, respectively). Postoperative complications occurred in 30 female and 33 male patients (15.6% and 17.1%, respectively). Patient age, smoking status, steroid use, perianal disease, presence of stoma, and presence of extra intestinal findings were significantly higher in the complicated group. Surgery may be inevitable for CD in the presence of complications. In cases of patient age, smoking, steroid use, perianal disease, stoma opening, and presence of extra intestinal findings, patients with CD who undergo surgery should be followed up closely in terms of the development of complications.

Orally administration of cerium oxide nanozyme for computed tomography imaging and anti-inflammatory/anti-fibrotic therapy of inflammatory bowel disease

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic nonspecific disease with unknown etiology. Currently, the anti-inflammatory therapeutic approaches have achieved a certain extent of effects in terms of inflammation alleviation. Still, the final pathological outcome of intestinal fibrosis has not been effectively improved yet.

RESULTS

In this study, dextran-coated cerium oxide (D-CeO₂) nanozyme with superoxide dismutase (SOD) and catalase (CAT) activities was synthesized by chemical precipitation. Our results showed that D-CeO₂ could efficiently scavenge reactive oxide species (ROS) as well as downregulate the pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, and iNOS) to protect cells from H₂O₂-induced oxidative damage. Moreover, D-CeO₂ could suppress the expression of fibrosis-related gene levels, such as α-SMA, and Collagen 1/3, demonstrating the anti-fibrotic effect. In both TBNS- and DSS-induced colitis models, oral administration of D-CeO₂ in chitosan/alginate hydrogel alleviated intestinal inflammation, reduced colonic damage by scavenging ROS, and decreased inflammatory factor levels. Notably, our findings also suggested that D-CeO₂ reduced fibrosis-related cytokine levels, predicting a contribution to alleviating colonic fibrosis. Meanwhile, D-CeO₂ could also be employed as a CT contrast agent for noninvasive gastrointestinal tract (GIT) imaging.

CONCLUSION

We introduced cerium oxide nanozyme as a novel therapeutic approach with computed tomography (CT)-guided anti-inflammatory and anti-fibrotic therapy for the management of IBD. Collectively, without appreciable systemic toxicity, D-CeO₂ held the promise of integrated applications for diagnosis and therapy, pioneering the exploration of nanozymes with ROS scavenging capacity in the anti-fibrotic treatment of IBD.

Guidelines for endoscopic balloon dilation in treating Crohn's disease-associated small intestinal strictures (supplement to the Clinical Practice Guidelines for Enteroscopy)

Balloon-assisted enteroscopy allows endoscopic treatments in the deeper segments of the small bowel. Endoscopic balloon dilation has become a popular minimally invasive alternative for the treatment of Crohn's disease-associated small intestinal strictures. As a supplement to the Clinical Practice Guidelines for Enteroscopy, the Japan Gastroenterological Endoscopy Society's Working Committee has developed the present "Guidelines for endoscopic balloon dilation in treating Crohn's disease-associated small intestinal strictures," based on new scientific techniques and evidence. The guidelines cover standard procedures for the insertion route of the balloon endoscope, bowel preparation, indications, procedure-related complications, efficacy, target diameter and duration, management of multiple strictures, and the current state of combined and alternative treatments. Unresolved future research questions are also listed in this guideline.

Endoscopic Treatment of Postoperative Bleeding, Bezoars, and Foreign Bodies

Altered gastrointestinal anatomy is common in patients with inflammatory bowel disease, particularly in those who underwent bowel surgery. Commonly performed surgeries are bowel resection and anastomosis and strictureplasty for Crohn's disease; and restorative proctocolectomy with ileal pouch-anal anastomosis for ulcerative colitis. The area of anastomosis and suture line is at the greatest risk for the development of postoperative bleeding. Altered bowel anatomy, especially the presence of strictures, strictureplasty, or structural or functional pouch outlet obstruction, puts these patients at risk for bezoar formation and foreign body retention, including video endoscopy capsule. This article will focus on postoperative bleeding, bezoar formation, and video capsule retention in patients with inflammatory bowel disease. Endoscopic management of these conditions is useful and is becoming an increasingly popular alternative to surgery.

MiR-21 regulates epithelial-mesenchymal transition in intestinal fibrosis of Crohn's disease by targeting PTEN/mTOR

BACKGROUND

Previous studies suggested miR-21 regulated epithelial-mesenchymal transition (EMT) and fibrosis in organs. The aim of this study was to explore the role and mechanism of miR-21 in EMT process of CD(Crohn's disease)-associated intestinal fibrosis.

METHODS

Tissue biopsies from fibrotic and nonfibrotic intestine of CD patients, and non-CD patients were obtained; chronic intestinal fibrosis model established by TNBS was treated with antagonist of miR-21; human intestinal epithelial cell, NCM460, were transfected with miR-21 mimics or inhibitor. The expressions of PTEN and mTOR, EMT-related markers and severity of colitis and fibrosis were examined.

RESULTS

Compared to the controls, miR-21 was significantly upregulated in the intestinal tissues from CD patients with fibro stenosis, followed by decreased PTEN expression, increased EMT markers, and mTOR expression, and imbalanced ratio of MMP9(matrix metalloproteinase 9)/TIMP1(tissue inhibitor of metalloproteinase 1). MiR-21 downregulated the expression of PTEN and upregulated mTOR signal in NCM460 cell. Also, knocking miR-21 down reduced EMT in vitro. Inhibiting miR-21 with antagonists reversed TNBS-induced intestinal fibrosis in vivo, through suppressing EMT and balancing MMPs/TIMPs.

CONCLUSION

We identified the involvement of miR-21 in EMT during intestinal fibrosis via targeting PTEN and mTOR, and miR-21 inhibition relieved intestinal fibrosis by regulating extracellular matrix (ECM) remodeling . Our results indicated miR-21 as a potential new target for the treatment of fibrosis complication in CD.

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.

The endoscopic prediction model of simple endoscopic score for Crohn’s disease (SES-CD) as an effective predictor of intestinal obstruction in Crohn’s disease: A multicenter long-term follow-up study

Background

The simple endoscopic score for Crohn's disease (SES-CD) is a widely used index to evaluate clinical and endoscopic activity. However, the association and predictive value of SES-CD for intestinal obstruction in Crohn's disease (CD) remains unclear. We aimed to establish the best cut-off indicators of SES-CD for early clinical intervention and subsequent prevention of intestinal obstruction in CD.

Methods

Data on patients with CD evaluated at our institute from January 2016 to January 2022 were retrospectively collected. The SES-CD and Crohn's Disease Activity Index scores used in the analysis indicated the results of the first clinical and colonoscopy evaluations after hospitalization. The primary outcome was the occurrence of intestinal obstruction during admission and follow-up.

Results

A total of 248 patients with a median follow-up time of 2 years [interquartile range: 1.0–4.0] were enrolled, of which 28.2% developed intestinal obstruction. An SES-CD score of 8 was the most significant threshold evaluation, and SES-CD ≥8 had the largest area under the receiver operating characteristic curve (0.705), with a sensitivity of 52.9% and specificity of 88.2% in predicting intestinal obstruction. Furthermore, SES-CD ≥8 had the greatest risk factor for intestinal obstruction (odds ratio: 7.731; 95% confidence interval: 3.901–15.322; p < 0.001) and significantly decreased the overall intestinal obstruction-free survival (p < 0.001).

Conclusion

The SES-CD endoscopic prediction model could be an effective predictor of intestinal obstruction in patients with CD. More frequent follow-up and colonoscopic surveillance should be considered in patients with SES-CD score ≥8 to prevent the development of intestinal obstruction.

Intestinal Ultrasound for Differentiating Fibrotic or Inflammatory Stenosis in Crohn's Disease: A Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Intestinal ultrasound [IUS] has been increasingly reported to distinguish inflammatory or fibrotic intestinal stenosis in Crohn's disease [CD] patients. However, the diagnostic value is unclear. This systematic review and meta-analysis aimed to assess the diagnostic role of different modes of IUS parameters.

METHODS

We searched PubMed, Embase, Web of Science, and Cochrane Library from inception to August 2021. Regarding effect sizes, weighted mean differences [WMDs] or standardised mean differences [SMDs] were used. We pooled data using a random-effects or fixed-effects model according to heterogeneity. The diagnostic accuracy of IUS for distinguishing fibrosis was pooled.

RESULTS

A total of 19 studies were retained for qualitative analysis, and 14 were included in the meta-analysis [with 511 total subjects and 635 bowel segments]. In patients with fibrotic stenosis, the pooled WMDs for bowel wall thickness were 1.30 mm (95% confidence interval [CI]: 0.69-1.91) thicker than in patients with inflammatory stenosis, and the pooled SMDs for strain value and strain ratio were 0.80 [95% CI: 0.41-1.20] and 1.08 [95% CI: 0.55-1.60] harder than in patients with inflammatory stenosis, respectively. The percentage of maximal enhancement of fibrotic stenosis was lower than that of inflammatory stenosis [WMD -10.03; 95% CI: -17.91- -2.16]. The diagnostic accuracy of IUS was not performed because only a few studies provided relevant diagnostic indicators, and these studies used different modes and parameters.

CONCLUSIONS

IUS currently is inaccurate to differentiate fibrotic or inflammatory stenosis in CD patients, and more studies assessing the significance of each parameter and its cut-off value in different modes of IUS are needed to be conducted in the future.

Therapeutic efficacy of human adipose mesenchymal stem cells in Crohn's colon fibrosis is improved by IFN-γ and kynurenic acid priming through indoleamine 2,3-dioxygenase-1 signaling

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic relapsing-remitting inflammatory diseases of the gastrointestinal tract that are typically categorized into two subtypes: Crohn's disease (CD) and ulcerative colitis (UC). Although MSCs therapy has achieved encouraging outcomes in IBD therapy, objective responses are limited in colon fibrosis stenosis owing to the complicated microenvironment of CD and MSCs heterogeneity of quality. Here, we chose IFN-γ and kynurenic acid (KYNA) to overcome the low response and heterogeneity of human adipose-derived MSCs (hADSCs) to treat IBD and expand the therapeutic effects based on the excellent ability of IFN-γ and KYNA to promote indoleamine 2,3-dioxygenase-1 (IDO-1) signaling, providing a potential protocol to treat IBD and fibrosis disease.

METHODS

hADSCs were isolated, cultured, and identified from human abdominal adipose tissue. The CD pathology-like acute colitis and chronic colon fibrosis rat model was induced by 2,4,6-trinitrobenzen sulfonic acid (TNBS). hADSCs were pretreated in vitro with IFN-γ and KYNA and then were transplanted intravenously at day 1 and 3 of TNBS administration in colitis along with at day 1, 15, and 29 of TNBS administration in chronic colonic fibrosis. Therapeutic efficacy was evaluated by body weights, disease activity index, pathological staining, real-time PCR, Western blot, and flow cytometry. For knockout of IDO-1, hADSCs were transfected with IDO-1-targeting small gRNA carried on a CRISPR-Cas9-lentivirus vector.

RESULTS

hADSCs treated with IFN-γ and KYNA significantly upregulated the expression and secretion of IDO-1, which has effectively ameliorated CD pathology-like colitis injury and fibrosis. Notably, the ability of hADSCs with IDO-1 knockout to treat colitis was significantly impaired and diminished the protective effects of the primed hADSCs with IFN-γ and KYNA.

CONCLUSION

Inflammatory cytokines IFN-γ- and KYNA-treated hADSCs more effectively alleviate TNBS-induced colitis and colonic fibrosis through an IDO-1-dependent manner. Primed hADSCs are a promising new strategy to improve the therapeutic efficacy of MSCs and worth further research.

Mesenteric Adipose Tissue Contributes to Intestinal Fibrosis in Crohn's Disease Through the ATX-LPA Axis

BACKGROUND AND AIMS

Intestinal fibrostenosis is an important cause of surgical intervention in patients with Crohn's disease [CD]. Hypertrophic mesenteric adipose tissue [MAT] is associated with the disease process of CD. The purpose of this study was to investigate the contribution of MAT to intestinal fibrosis.

METHODS

MAT from surgical specimens of fibrostenotic CD patients and controls was collected for measurement of the levels of autotaxin [ATX] and lysophosphatidic acid [LPA]. ATX was inhibited in vivo in DNBS [dinitrobenzene sulfonic acid]-induced colitis mice, which were evaluated for colonic inflammation and fibrosis. 3T3-L1 cells and primary colonic fibroblasts were used in vitro to investigate the interaction between MAT and intestinal fibrosis, as well as the molecular mechanism underlying this interaction.

RESULTS

MAT adjacent to the fibrostenotic intestine in CD patients showed an activated ATX-LPA axis. An in vivo study indicated that inhibition of ATX was associated with the improvement of morphology and function of diseased MAT, which was combined with ameliorated intestinal inflammation and fibrosis in DNBS-instilled mice. In vitro studies showed that hypoxia stimulated adipocyte ATX expression and that LPA stabilized adipocyte HIF-1α protein, forming an ATX-LPA-HIF-1α amplification loop and aggravating adipocyte dysfunction. LPA secreted by adipocytes bound to LPA1 on the surface of fibroblasts, promoted their proliferation and differentiation, and increased the expression of fibrosis-related factors.

CONCLUSIONS

The ATX-LPA axis regulated intestinal fibrosis by influencing the proliferation and differentiation of intestinal fibroblasts. Inhibiting this axis may be a therapeutic target for intestinal fibrosis in CD.

Endoscopic small bowel balloon dilations in patients with Crohn's disease: a Danish nationwide cohort study, 1997-2015

OBJECTIVE

Small bowel strictures are a common complication in Crohn's disease. Endoscopic balloon dilation (EBD) is an emerging therapeutic approach that is minimally invasive and helps to preserve the bowel. The aim of this study was to describe the use of EBD in adult Crohn's disease patients with small bowel strictures.

METHODS

This nationwide cohort comprised individuals ≥18 years old, diagnosed with Crohn's disease in Denmark between 1 January 1997 and 31 December 2015, according to the National Patient Registry (NPR).

RESULTS

The cohort consisted of 9737 incident Crohn's disease patients that were followed for a median of 8.2 years [interquartile range (IQR) = 4.1-13.3]. During the observation period, a total of 90 (1%) patients underwent a small bowel-related EBD. After a follow-up period of a median of 3.4 (IQR = 1.8-5.0) years, primary small bowel strictures treated only with one dilation and no subsequent small bowel surgery accounted for 29 (59%) of 49 cases. A median of 7.2 (IQR = 2.4-13.2) months after their first dilation, 13 (27%) of those 49 patients underwent small bowel surgery. Forty-one patients with postsurgical strictures were dilated after a median of 6.5 (IQR = 2.5-10.2) years following small bowel surgery. Postsurgical strictures treated with only one dilation and no further small bowel surgery accounted for 20 (49%) of the 41 cases.

CONCLUSION

The frequency of EBD in this Danish nationwide cohort was low. During a median follow-up of 5 years after EBD, most patients did not require further surgery. This suggests that EBD is an effective treatment and could be offered to more patients with Crohn's disease.

Inflammation and tissue remodeling contribute to fibrogenesis in stricturing Crohn’s disease: image processing and analysis study

Background

Inflammation and structural remodeling may contribute to fibrogenesis in Crohn’s disease (CD). We quantified the immunoexpression of calretinin, CD34, and calprotectin as a surrogate for mucosal innervation, telocytes (interstitial cells playing a role in networking), and inflammation, respectively, and correlated them with bowel alterations in stricturing CD.

Methods

Primary resection specimens for ileal CD (n = 44, 31 stricturing CD, 13 inflammatory CD) were identified. Left-sided ulcerative colitis and trauma cases were used as controls. Proximal and distal margin and middle (diseased) sections were stained for calretinin, CD34, and calprotectin. Microscopic images were captured from the mucosa (calretinin), submucosa (calprotectin), and myenteric plexus (CD34), and the immunostaining was quantified using image processing and analysis. Bowel thickness at the corresponding sections were measured and correlated with the amount of immunoexpression.

Results

A total of 2,037 images were analyzed. In stricturing CD, submucosal alteration/thickening at the stricture site correlated with calprotectin staining and inversely correlated with calretinin staining at the proximal margin. Muscularis propria alteration/thickening at the stricture site correlated with mucosal calretinin staining at the proximal margin. Submucosal alteration/thickening at the proximal margin correlated with calretinin and CD34 staining at the proximal margin and inversely correlated with CD34 staining at the stricture site. Calretinin immunostaining at the distal margin was significantly higher in stricturing CD than the controls.

Conclusions

Inflammation and tissue remodeling appear to contribute to fibrogenesis in stricturing CD. Increased mucosal calretinin immunostaining distal to the diseased segment could be helpful in diagnosing CD in the right clinical context.

Metformin Ameliorates Chronic Colitis-Related Intestinal Fibrosis via Inhibiting TGF-β1/Smad3 Signaling

Intestinal fibrosis is considered to be a chronic complication of inflammatory bowel disease (IBD) and seriously threatening human health. Effective medical therapies or preventive measures are desirable but currently unavailable. Metformin has been proved to have a satisfactory anti-inflammatory effects in ulcerative colitis (UC) patients. Whether metformin can ameliorate chronic colitis-related intestinal fibrosis and the possible mechanisms remain unclear. Here, we established colitis-related intestinal fibrosis in mice by repetitive administration of TNBS or DSS. Preventive and therapeutic administration of metformin to chronic TNBS or DSS colitis mice indicated that metformin significantly attenuated intestinal fibrosis by suppressing Smad3 phosphorylation. In vitro studies with human colon fibroblast cell line (CCD-18Co) and primary human intestinal fibroblast treated with TGF-β1 confirmed the anti-fibrotic function of metformin for fibroblast activation, proliferation and collagen production. Mechanistically, metformin particularly inhibited phosphorylation and nuclear translocation of Smad3 by blocking the interaction of Smad3 with TβRI. These findings suggest that metformin will be an attractive anti-fibrotic drug for intestinal fibrosis in future therapies.

Effect of smoking on the development and outcomes of inflammatory bowel disease in Taiwan: a hospital-based cohort study

Smoking influences the risks of inflammatory bowel disease (IBD). A hospital-based cohort was conducted to evaluate the effect of smoking on the development and outcomes of IBD, with age, sex and comorbidities matched non-IBD controls from the National Health Interview Survey database of Taiwan. 700 IBD patients (360 ulcerative colitis (UC), 340 Crohn’s disease (CD)) were analyzed for outcomes; and 575 patients (297 UC, 278 CD) were analyzed for prevalence. Smoking prevalence was significantly lower in UC patients than controls (20.9% vs. 30.4%, p < 0.01), but no difference between CD patients and controls (19.8% vs. 22.1%, p = 0.60). UC smokers had fewer admissions (1.6 vs. 2.5, p < 0.05) but higher rates of new cancer development (16% vs. 6.7%, p < 0.05) and mortality (16% vs. 4.9%, p < 0.01) than nonsmokers. CD smokers tended to have higher rates of stricturing and penetrating diseases (p < 0.05), and higher surgery risk (60.3% vs. 38.3%, p < 0.01) than nonsmokers. Smoking prevents UC occurrence and is associated with fewer hospitalization but increases risks of cancer and mortality. By contrast, smoking does not affect CD occurrence but is related to more aggressive behavior which results in a higher surgical rate.

Association of Circulating Fibrocytes With Fibrostenotic Small Bowel Crohn's Disease

BACKGROUND

Fibrocytes are hematopoietic cells with features of mesenchymal cells found in the circulation and inflammatory sites implicated in promoting fibrosis in many fibroinflammatory diseases. However, their role(s) in the development of intestinal fibrosis is poorly understood. Here, we investigated a potential role of fibrocytes in the development of fibrosis in Crohn's disease (CD) and sought factors that may impact their development and function.

METHODS

Plasma and mononuclear cells were collected from patients with and without fibrostenotic CD. Fibrocytes defined as CD11b+, CD34+, and Collagen 1+ were correlated with clinical assessments of fibrosis, including evaluation using intestinal ultrasound. We measured the levels of relevant circulating molecules via Luminex and studied the effect of patient plasma proteins on fibrocyte differentiation.

RESULTS

Fibrocyte numbers were increased in CD patients with stricturing Crohn's disease compared with patients with an inflammatory phenotype (P = .0013), with strong correlation between fibrocyte numbers and acoustic radiation force impulse (ARFI), a measure of bowel elasticity on intestinal ultrasound (R = .8383, P = .0127). Fibrostenotic plasma was a more potent inducer of fibrocyte differentiation in both primary human monocytes and cell line and contained increased levels of cytokines implicated in fibrocyte differentiation compared with plasma from inflammatory patients. Interestingly, increased fibrocyte numbers at time of ultrasound were associated with escalation of medical therapy and endoscopic/surgical management of small bowel strictures at 30 months follow-up.

CONCLUSIONS

Circulating fibrocytes strongly correlate with fibrostenotic disease in CD, and they may serve as predictors for escalation of medical +/- surgical therapy.

The Possible Pathogenic Role of IgG4-Producing Plasmablasts in Stricturing Crohn's Disease

BACKGROUND

Crohn's disease (CD) is a condition on the spectrum of inflammatory bowel disease that affects up to 20 people per 100,000 in the US annually, and with incidence increasing. One of the most significant sources of morbidity in CD is the formation of strictures, with resultant intestinal blockage a common indication for hospitalization and surgical intervention in these patients. The pathophysiology of stricture formation is not fully understood. However, the fibroplasia that leads to fibrostenotic stricture formation may have shared pathophysiology with IgG4-related fibrosis.

SUMMARY

Initial intestinal inflammation recruits innate immune cells, such as neutrophils, that secrete IL-1β and IL-23, which induces a type 17 CD4+ T-helper T-cell (Th17)-mediated adaptive immune response. These CD4+ Th17 T cells also contribute to inflammation by secreting proinflammatory cytokines such as IL-17 and IL-21. IL-21 recruits and stimulates CD4+ T follicular helper (Tfh) cells, which secrete more IL-21. This causes ectopic germinal center formation, recruiting and stimulating naïve B cells. The IL-17 and IL-21 produced by Th17 cells and Tfh cells also induce IgG4 plasmablast differentiation. Finally, these IgG4-producing plasmablasts secrete platelet-derived growth factor (PDGF), which activates local PDGF-receptor expressing fibroblasts and myofibroblasts, resulting in uncontrolled fibroplasia.

A Novel Cause of Bowel Obstruction in a Patient with Long-Standing Crohn's Disease

Solitary fibrous tumors are rare tumors of mesenchymal origin. Although most often observed in the lung pleura, they have been reported in varied extrapleural sites. A 70-year-old male with complicated Crohn's disease presented with 3 days of nausea, emesis, constipation, and abdominal pain. Computed Tomography (CT) demonstrated mucosal thickening of the middescending colon, consistent with fibrosing stricture. Surgical excision revealed an unusual, 5 cm mass originating in the subserosa. Histopathology of the lesion was notable for a proliferation of cells with spindle and stellate-shaped nuclei and no appreciable mitotic figures, which extended into the muscularis and submucosa. Immunohistochemistry was STAT6 nuclear positive and cytoplasmic CD34 positive, diagnostic for solitary fibrous tumor (SFT). In this case, the SFT infiltrating into the muscularis propria and subserosa caused the stricture and bowel obstruction. This illustrates that while fibrosing strictures are usually the etiology of bowel obstruction in the setting of Crohn's disease, other rare possible causes should be considered.

Outcomes of Passable and Non-passable Strictures in Clinical Trials of Crohn's Disease: A Post-hoc Analysis

BACKGROUND AND AIMS

There is paucity of evidence on the reversibility of Crohn's disease [CD]-related strictures treated with therapies. We aimed to describe the clinical and endoscopic outcomes of CD patients with non-passable strictures.

METHODS

This was a post-hoc analysis of three large CD clinical trial programmes examining outcomes with infliximab, ustekinumab, and azathioprine, which included data on 576 patients including 105 with non-passable strictures and 45 with passable strictures, as measured using the Simple Endoscopic Score for Crohn's Disease [SES-CD]. The impact of non-passable strictures on achieving clinical remission [CR] and endoscopic remission [ER] was assessed using multivariate logistic regression models. CR was defined as a Crohn's Disease Activity Index [CDAI] <150, clinical response as a CDAI reduction of ≥100 points, and ER as SES-CD score <3.

RESULTS

After 1 year of treatment, patients with non-passable strictures demonstrated the ability to achieve passable or no strictures in 62.5% of cases, with 52.4% and 37.5% attaining CR and ER, respectively. However, patients with non-passable strictures at baseline were less likely to demonstrate symptom improvement compared with those with passable or no strictures, with reduced odds of 1-year CR (adjusted odds ratio [aOR] 0.17, 95% CI 0.03-0.99, p = 0.048). No significant differences were observed between patients with non-passable strictures at baseline and those with passable or no strictures in rates of ER [aOR 0.82, 95% CI 0.23-2.85, p = 0.751] at 1 year.

CONCLUSIONS

Patients with non-passable strictures can achieve symptomatic and endoscopic remission when receiving therapies used to treat CD, although they are less likely to obtain CR compared with patients without non-passable strictures. These findings support the importance of balancing the presence of non-passable strictures in trial arms.

CT and MRI Evaluations in Crohn's Complications: A Guide for the Radiologist

Inflammatory bowel diseases (IBD) are a group of chronic inflammatory intestinal conditions with unknown etiology. Crohn's disease (CD) and ulcerative colitis (UC) are the two main types of IBD and they have some interchangeable and some different clinical and pathological characteristics. When diagnosis is performed for the first time, the majority of CD patients have a predominant inflammatory condition. As the disease progresses most patients experience the development of complications, such as abscesses, fistulas, perforation, strictures, and others. Both computed tomography (CT) and Magnetic Resonance Imaging (MRI) allow great view of the whole length of the intestinal tract together with the eventual extra-and intra-intestinal complications. MR enterography (MRE) and CT enterography (CTE), performed after oral administrations of contrast medium, have similar diagnostic accuracy for the diagnosis of CD and its complications. Even though CT is still the most familiar diagnostic technique used for studying CD worldwide, MRE have several important benefits that are leading to rapid increase in its employment in the last years. In particular, MRE allows a superior soft tissue contrast resolution compared to CT, offering a better visualization of bowel wall and its inflammatory and fibrotic characteristics. Moreover, Pelvic Magnetic Resonance is the principal technique in patients with perianal disease due to its ability of providing precise and fine detail images of the sphincter complex, which are crucial for evaluating pelvic disease. In this paper we describe common and uncommon complications in patients with CD, and explain how to identify their findings in CT and MR exams.

NOD/scid IL-2Rγnull mice reconstituted with peripheral blood mononuclear cells from patients with Crohn's disease reflect the human pathological phenotype

Introduction

Crohn's disease (CD) is characterized by pronounced intestinal fibrosis and severe mucosal damage and conventional animal models are limited to reflect these pathological manifestations. The aim of this study was to examine whether the combination of patient immune‐profiling and preclinical studies in a mouse model based on NOD/scid IL‐2Rγ^null (NSG) reconstituted with peripheral blood mononuclear cells (PBMC) from CD patients has the capacity to harmonize ex vivo human and in vivo animal studies.

Methods

Immunological profiles of CD (n = 24) and ulcerative colitis (UC) patients (n = 47) were established by flow cytometry of subgroups of immune cells and subjected to hierarchical cluster and estimation graphics analyses. Pathological phenotypes of NSG mice, which were reconstituted with PBMC from CD, UC, and non‐IBD donors (NSG‐CD, NSG‐UC, and NSG‐non‐IBD) were compared. Readouts were the clinical, colon, and histological scores; subtypes of immune cells from spleen and colon; and levels of inflammatory markers, such as c‐reactive protein (CRP), monocyte chemotactic protein (MCP)‐3, transforming growth factor‐beta (TGFß), and hepatocyte growth factor (HGF). Fibrocytes were identified by immunohistochemistry in colonic sections.

Results

CD patients were significantly clustered in a group characterized by increased levels of TH1, TH2 cells, and decreased levels of CD14+ CD163+ monocytes (p = .003). In contrast to NSG‐UC mice, NSG‐CD mice exhibited an immune‐remodeling phenotype characterized by enhanced collagen deposition, elevated levels of CD14+ CD163+ monocytes, HGF, and TGFß. This phenotype was further corroborated by the presence of human fibrocytes as components of fibrotic areas.

Conclusion

The NSG‐CD model partially reflects the human disease and allows for studying the development of fibrosis.

Shear Wave and Strain Elastography in Crohn's Disease-A Systematic Review

One modern imaging technique used in the diagnosis of Crohn’s disease (CD) is sonoelastrography of the intestine. Guidelines regarding the use of bowel sonoelastography in CD have still not been specified. The aim of our research was to conduct a systematic review of the use of sonoelastography in the diagnosis, assessment, and monitoring of strictures in the course of CD. A systematic review was conducted according to the PRISMA guidelines statement. The following databases were searched in January 2021: MEDINE via PubMed, Embase and Scopus. The search utilised the following MeSH tags: ‘Ultrasound Shear Wave’, ‘Elastography’, ‘elastogram’, ‘elastographies’ AND ‘Crohn disease’. The inclusion criteria were as follows: from 2010 or later, articles with abstracts, articles in English, human-based studies and original articles. Articles were assessed independently by two reviewers. Out of 181 articles, only 15 met the criteria and were included in the review. Due to a small number of studies and significant methodological differences, the feasibility of using sonoelastography for Crohn’s disease must be proven through further research and analysis. In the future, standardised assessment criteria and cut-off points should be established for both strain elastography (SE) and shear wave elastography (SWE).

Therapeutic Targeting of Nrf2 Signaling by Maggot Extracts Ameliorates Inflammation-Associated Intestinal Fibrosis in Chronic DSS-Induced Colitis

Intestinal fibrosis is induced by excessive myofibroblast proliferation and collagen deposition, which has been regarded as a general pathological feature in inflammatory bowel disease (IBD). Therefore, identifying clinical markers and targets to treat and prevent intestinal fibrosis is urgently needed. The traditional Chinese medicine maggot, commonly known as “wu gu chong”, has been shown to reduce oxidative stress and alleviate inflammation in chronic colitis. This study investigated the mechanisms underlying the effects of maggot extract (ME) on inflammation-associated intestinal fibrosis in TGF-β1-stimulated human intestinal fibroblasts (CCD-18Co cells) and dextran sodium sulphate (DSS)-induced chronic colitis murine model. To assess the severity of inflammation and fibrosis, histological and macroscopic evaluation were carried out. The results showed that ME was a significant inhibitor of body weight loss and colon length shortening in mice with chronic colitis. In addition, ME suppressed the intestinal fibrosis by downregulating TGF-β1/SMADs pathway via upregulation of Nrf2 expression at both protein and mRNA levels. ME markedly increased the expression of Nrf2, thus resulting in a higher level of HO-1. After treatment with Nrf2 inhibitor (ML385) or siRNA-Nrf2 for deactivating Nrf2 pathway, the protective effects of ME were abolished both in vitro and in vivo. Moreover, the histopathological results for the major organs of DSS mice treated with ME showed no signs of clinically important abnormalities. Treatment with ME had no effect on the viability of CCD-18Co cells, suggesting its low in vitro cytotoxicity. Furthermore, ME could mediate intestine health by keeping the balance of the gut microbes through the enhancement of beneficial microbes and suppression of pathogenic microbes. In conclusion, this is the first ever report demonstrating that ME ameliorates inflammation-associated intestinal fibrosis by suppressing TGF-β1/SMAD pathway via upregulation of Nrf2 expression. Our findings highlight the potential of Nrf2 as an effective therapeutic target for alleviating intestinal fibrosis.

Bowel stiffness associated with histopathologic scoring of stenosis in patients with Crohn's disease

BACKGROUND AND AIMS

Intestinal stenosis is a common complication of Crohn's Disease (CD). Stenosis is associated with alteration of bowel mechanical properties. This study aims to quantitate the mechanical properties of the intestinal stenosis and to explore associations between histology and mechanical remodeling at stenotic intestinal sites in CD patients.

METHODS

Intestinal segments from stenotic sites were studied in vitro from 19 CD patients. A luminal catheter with a bag was used to stepwise pressurize the intestinal segments from 0-100 cmH₂O with 10 cmH₂O increments. B-mode ultrasound images were obtained at the narrowest part of the stenosis at each pressure level and morphometric parameters were obtained from ultrasound images. The mechanical behavior of the stenotic tissue were characterized by using an isotropic three dimensional strain energy function in Demiray model form, the mechanical constants were obtained by fitting the model to the recorded intraluminal pressure and the inner radius of the stenotic segment of the small bowel. Grading scores were used for histological analysis of inflammation, fibrosis, muscular hypertrophy and adipocyte proliferation in the intestinal layers. The collagen area fraction in intestinal layers was also calculated. Associations between histological and the mechanical constants (stiffness) were analyzed.

RESULTS

Chronic inflammation was mainly located in mucosa whereas fibrosis was found in submucosa. The mechanical remodeling was performed with changed mechanical constants ranged between 0.35-13.68kPa. The mechanical properties changes were associated mainly with chronic inflammation, fibrosis and combination of inflammation and fibrosis (R>0.69, P<0.001). Furthermore, the mechanical properties correlated with the collagen fraction in submucosa and muscular layers (R>0.53, P<0.05).

CONCLUSIONS

We quantitated the intestinal stenosis stiffness. Associations were found between bowel mechanical remodeling and histological changes at the stenotic site in CD patients.

STATEMENT OF SIGNIFICANCE

Although intestinal ultrasonography, CT and MRI can be used to diagnose Crohn's Disease (CD)-associated bowel strictures, these techniques may not have sufficient accuracy and resolution to differentiate predominantly inflammatory strictures from predominantly fibrotic strictures. The present study aims to quantitate the mechanical remodeling of intestinal stenosis and to explore the associations between histological parameters and mechanical properties at the intestinal stenotic sites in CD patients. For the first time, we quantitatively demonstrated that the mechanical properties of the intestinal wall in CD stenosis are associated with the chronic inflammation, fibrosis and collagen fraction in the intestinal layers. The results of this study may facilitate design and development of artificial biomaterials for gastrointestinal organs. The potential clinical implication of this study is that the histological characteristics in patients with CD can be predicted clinically by means of inflammation and fibrosis assessment in conjunction with tissue stiffness measurement.

[Position paper on endoscopic reporting in IBD]

The complete and reliable documentation of endoscopic findings make up the crucial foundation for the treatment of patients with inflammatory bowel diseases such as Crohn´s disease and ulcerative colitis. These findings are, on the one hand, a prerequisite for therapeutic decisions and, on the other hand, important as a tool for assessing the response to ongoing treatments. Endoscopic reports should, therefore, be recorded according to standardized criteria to ensure that the findings of different endoscopists can be adequately compared and that changes in the course of the disease can be traced back. In consideration of these necessities, fifteen members of the Imaging Working Group of the German Kompetenznetz Darmerkrankungen have created a position paper proposing a structure and specifications for the documentation of endoscopic exams. In addition to the formal report structure, the recommendations address a large number of attributes of acute and chronic inflammatory alterations as well as endoscopically detectable complications, which are explained in detail and illustrated using exemplary images. In addition, more frequently used endoscopic activity indices are presented and their use in everyday clinical practice is discussed.

Intestinal stricture in Crohn's disease: A 2020 update

Crohn's disease (CD) is a chronic and relapsing-remitting inflammatory disorder of the gastrointestinal tract. Approximately 70% of patients inevitably develop fibrosis-associated intestinal stricture after 10 years of CD diagnosis, which seriously affects their quality of life. Current therapies play limited role in preventing or reversing the process of fibrosis and no specific anti-fibrotic therapy is yet available. Nearly half of patients thus have no alternative but to receive surgery. The potential mechanisms of intestinal fibrosis remain poorly understood; extracellular matrix remodeling, aberrant immune response, intestinal microbiome imbalance and creeping fat might exert fundamental influences on the multiple physiological and pathophysiological processes. Recently, the emerging new diagnostic techniques have markedly promoted an accurate assessment of intestinal stricture by distinguishing fibrosis from inflammation, which is crucial for guiding treatment and predicting prognosis. In this review, we concisely summarized the key studies published in the year 2020 covering pathogenesis, diagnostic modalities, and therapeutic strategy of intestinal stricture. A comprehensive and timely review of the updated researches in intestinal stricture could provide insight to further elucidate its pathogenesis and identify novel drug targets with anti-fibrotic potentiality.

Noncoding RNAs as Promising Diagnostic Biomarkers and Therapeutic Targets in Intestinal Fibrosis of Crohn's Disease: The Path From Bench to Bedside

Fibrosis is a major pathway to organ injury and failure, accounting for more than one-third of deaths worldwide. Intestinal fibrosis causes irreversible and serious clinical complications, such as strictures and obstruction, secondary to a complex pathogenesis. Under the stimulation of profibrotic soluble factors, excessive activation of mesenchymal cells causes extracellular matrix deposition via canonical transforming growth factor-β/Smads signaling or other pathways (eg, epithelial-to-mesenchymal transition and endothelial-to-mesenchymal transition) in intestinal fibrogenesis. In recent studies, the importance of noncoding RNAs (ncRNAs) stands out in fibrotic diseases in that ncRNAs exhibit a remarkable variety of biological functions in modulating the aforementioned fibrogenic responses. In this review, we summarize the role of ncRNAs, including the emerging long ncRNAs and circular RNAs, in intestinal fibrogenesis. Notably, the translational potential of ncRNAs as diagnostic biomarkers and therapeutic targets in the management of intestinal fibrosis is discussed based on clinical trials from fibrotic diseases in other organs. The main points of this review include the following: • Characteristics of ncRNAs and mechanisms of intestinal fibrogenesis • Wide participation of ncRNAs (especially the emerging long ncRNAs and circular RNAs) in intestinal fibrosis, including transforming growth factor-β signaling, epithelial-to-mesenchymal transition/endothelial-to-mesenchymal transition, and extracellular matrix remodeling • Translational potential of ncRNAs in the diagnosis and treatment of intestinal fibrosis based on clinical trials from fibrotic diseases in other organs.