Intestinal Fibrosis In Crohn's Disease Research Articles

Multiomics reveals microbial metabolites as key actors in intestinal fibrosis in Crohn's disease.

Intestinal fibrosis is the primary cause of disability in patients with Crohn's disease (CD), yet effective therapeutic strategies are currently lacking. Here, we report a multiomics analysis of gut microbiota and fecal/blood metabolites of 278 CD patients and 28 healthy controls, identifying characteristic alterations in gut microbiota (e.g., Lachnospiraceae, Ruminococcaceae, Muribaculaceae, Saccharimonadales) and metabolites (e.g., L-aspartic acid, glutamine, ethylmethylacetic acid) in moderate-severe intestinal fibrosis. By integrating multiomics data with magnetic resonance enterography features, putative links between microbial metabolites and intestinal fibrosis-associated morphological alterations were established. These potential associations were mediated by specific combinations of amino acids (e.g., L-aspartic acid), primary bile acids, and glutamine. Finally, we provided causal evidence that L-aspartic acid aggravated intestinal fibrosis both in vitro and in vivo. Overall, we offer a biologically plausible explanation for the hypothesis that gut microbiota and its metabolites promote intestinal fibrosis in CD while also identifying potential targets for therapeutic trials.

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.

A NEW MODEL TO STUDY INTESTINAL FIBROSIS USING IPSC-DERIVED HUMAN EPITHELIAL AND MESENCHYMAL CELLS FROM CROHN’S DISEASE PATIENTS

Abstract INTRODUCTION Intestinal fibrosis is a serious complication of Crohn's disease (CD) and is caused by the excess deposition of extracellular matrix protein. There are no therapies to prevent or treat this and surgical intervention remains the only treatment option. Numerous cell types, including intestinal epithelial and mesenchymal cells, are implicated in this but research efforts are impaired by a lack of in vitro models. Human intestinal organoids (HIOs), derived from induced pluripotent stem cells (iPSCs), are comprised of both of these cell types; therefore iPSC-derived HIOs represent an approach in which an unlimited number of patient specific cells could be generated for such models. Our goal was to confirm the feasibility of using iPSC-derived epithelial and mesenchymal cells from CD patients to model intestinal fibrosis METHODS iPSCs from CD patients with and without fibrotic complications were directed to form HIOs. As iPSC-derived HIOs contain epithelial and mesenchymal cells, the organoids were dissociated to generate purified cultures of epithelial-only HIOs (eHIOs) and mesenchymal cells. Both cell types were cultured with TNFα and TGFβ, and responses were assayed after 8, 24 and 48 hrs. Further assessment on the transcriptomic profile of the cultures was conducted using the Nanostring nCounter Fibrosis Panel. RESULTS Mesenchymal cells treated with TNFα for 48 hrs showed a significant increase in MMP9 expression, whereas TGFβ elicited an upregulation in COL1A1 and COL5A1. Further analysis via Nanostring identified the upregulation of numerous other fibrosis-related genes in response to TNFα stimulation, mainly: CCL2, IL6, MMP7, and MMP9. In eHIO cultures, after 24 hrs of cytokine exposure, we detected a significant upregulation in EMT (NCAD, VIM, and SNAI2) and fibrosis genes (COL1A1, COL5A1, and MMP9), mainly in response to TGFβ and the combination TNFα/TGFβ. Nanostring further identified a total of 121 differentially expressed genes, mostly in response to these treatments, particularly: CCL2, IL11, MMP9, MMP10. Overall, Nanostring analysis found an upregulation in pathways associated with ECM production and remodeling, immunomodulation, and ligands associated with EMT and cell migration. CONCLUSION We have successfully generated a system to assay intestinal fibrosis in a patient-specific manner using iPSC-derived epithelial and mesenchymal cells from CD patients. Our model elicited a reliable and reproducible response to inflammatory and fibrogenic stimuli, measured by the differential expression of key fibrosis-associated genes. Future studies will focus on a broader analysis of these data via RNA-seq to investigate a potential fibrogenic phenotype and to identify novel genes/pathways that may play in role in the pathophysiology of intestinal fibrosis in CD.

Contribution of the Gut Microbiota to Intestinal Fibrosis in Crohn's Disease.

In Crohn's disease (CD), intestinal fibrosis is a critical determinant of a patient's prognosis. Although inflammation may be a prerequisite for the initiation of intestinal fibrosis, research shows that the progression or continuation of intestinal fibrosis can occur independently of inflammation. Thus, once initiated, intestinal fibrosis may persist even if medical treatment controls inflammation. Clearly, an understanding of the pathophysiological mechanisms of intestinal fibrosis is required to diminish its occurrence. Accumulating evidence suggests that the gut microbiota contributes to the pathogenesis of intestinal fibrosis. For example, the presence of antibodies against gut microbes can predict which CD patients will have intestinal complications. In addition, microbial ligands can activate intestinal fibroblasts, thereby inducing the production of extracellular matrix. Moreover, in various animal models, bacterial infection can lead to the development of intestinal fibrosis. In this review, we summarize the current knowledge of the link between intestinal fibrosis in CD and the gut microbiota. We highlight basic science and clinical evidence that the gut microbiota can be causative for intestinal fibrosis in CD and provide valuable information about the animal models used to investigate intestinal fibrosis.

Development of antifibrotic therapy for stricturing Crohn's disease: lessons from randomized trials in other fibrotic diseases.

Intestinal fibrosis is considered an inevitable complication of Crohn's disease (CD) that results in symptoms of obstruction and stricture formation. Endoscopic or surgical treatment is required to treat the majority of patients. Progress in the management of stricturing CD is hampered by the lack of effective antifibrotic therapy; however, this situation is likely to change because of recent advances in other fibrotic diseases of the lung, liver, and skin. In this review, we summarize data from randomized controlled trials (RCTs) of antifibrotic therapies in these conditions. Multiple compounds have been tested for antifibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, intracellular enzymes and kinases, renin-angiotensin system (RAS) modulators, and others. From our review of the results from the clinical trials and discussion of their implications in the gastrointestinal tract, we have identified several molecular candidates that could serve as potential therapies for intestinal fibrosis in CD.

From good to bad fibroblasts: New promising targets to cure Crohn's disease.

From good to bad fibroblasts: New promising targets to cure Crohn's disease.

Development and Validation of a Novel Computed-Tomography Enterography Radiomic Approach for Characterization of Intestinal Fibrosis in Crohn’s Disease

No reliable method for evaluating intestinal fibrosis in Crohn's disease (CD) exists; therefore, we developed a computed-tomography enterography (CTE)-based radiomic model (RM) for characterizing intestinal fibrosis in CD. This retrospective multicenter study included 167 CD patients with 212 bowel lesions (training, 98 lesions; test, 114 lesions) who underwent preoperative CTE and bowel resection at 1 of the 3 tertiary referral centers from January 2014 through June 2020. Bowel fibrosis was histologically classified as none-mild or moderate-severe. In the training cohort, 1454 radiomic features were extracted from venous-phase CTE and a machine learning-based RM was developed based on the reproducible features using logistic regression. The RM was validated in an independent external test cohort recruited from 3 centers. The diagnostic performance of RM was compared with 2 radiologists' visual interpretation of CTE using receiver operating characteristic (ROC) curve analysis. In the training cohort, the area under the ROC curve (AUC) of RM for distinguishing moderate-severe from none-mild intestinal fibrosis was 0.888 (95% confidence interval [CI], 0.818-0.957). In the test cohort, the RM showed robust performance across 3 centers with an AUC of 0.816 (95% CI, 0.706-0.926), 0.724 (95% CI, 0.526-0.923), and 0.750 (95% CI, 0.560-0.940), respectively. Moreover, the RM was more accurate than visual interpretations by either radiologist (radiologist 1, AUC= 0.554; radiologist 2, AUC= 0.598; both, P < .001) in the test cohort. Decision curve analysis showed that the RM provided a better net benefit to predicting intestinal fibrosis than the radiologists. A CTE-based RM allows for accurate characterization of intestinal fibrosis in CD.

Cross-sectional imaging for assessing intestinal fibrosis in Crohn's disease.

More than 30% of patients with Crohn's disease (CD) develop fibrotic strictures in the bowel as the disease progresses. Excessive deposition of extracellular matrix components in the submucosa and smooth muscle hypertrophy or hyperplasia are the main features of fibrosis in CD. Cross-sectional imaging technology provides a wealth of information on the anatomy, histological composition, and physiological function of the bowel, allowing for a non-invasive and complete evaluation of associated abnormalities. This review summarizes recent advances in and the potential technologies of cross-sectional imaging for assessing intestinal fibrosis in CD, including ultrasound imaging, computed tomography, and magnetic resonance imaging.

Comparison of Three Magnetization Transfer Ratio Parameters for Assessment of Intestinal Fibrosis in Patients with Crohn's Disease.

ObjectiveTo establish a novel standardized magnetization transfer ratio (MTR) parameter which considers the element of the normal bowel wall and to compare the efficacy of the MTR, normalized MTR, and standardized MTR in evaluating intestinal fibrosis in Crohn's disease (CD).Materials and MethodsAbdominal magnetization transfer imaging from 20 consecutive CD patients were analyzed before performing elective operations. MTR parameters were calculated by delineating regions of interest in specified segments on MTR maps. Specimens with pathologically confirmed bowel fibrosis were classified into one of four severity grades. The correlation between MTR parameters and fibrosis score was tested by Spearman's rank correlation. Differences in MTR, normalized MTR, and standardized MTR across diverse histologic fibrosis scores were analyzed using the independent sample t test or the Mann-Whitney U test. The area under the receiver operating characteristic curve (AUC) was computed to test the efficacies of the MTR parameters in differentiating severe intestinal fibrosis from mild-to-moderate fibrosis.ResultsNormalized (r = 0.700; p < 0.001) and standardized MTR (r = 0.695; p < 0.001) showed a strong correlation with bowel fibrosis scores, followed by MTR (r = 0.590; p < 0.001). Significant differences in MTR (t = −4.470; p < 0.001), normalized MTR (Z = −5.003; p < 0.001), and standardized MTR (Z = −5.133; p < 0.001) were found between mild-to-moderate and severe bowel fibrosis. Standardized MTR (AUC = 0.895; p < 0.001) had the highest accuracy in differentiating severe bowel fibrosis from mild-to-moderate bowel wall fibrosis, followed by normalized MTR (AUC = 0.885; p < 0.001) and MTR (AUC = 0.798; p < 0.001).ConclusionStandardized MTR is slightly superior to MTR and normalized MTR and therefore may be an optimal parameter for evaluating the severity of intestinal fibrosis in CD.

Parathyroid Hormone–Like Hormone Induces Epithelial-to-Mesenchymal Transition of Intestinal Epithelial Cells by Activating the Runt-Related Transcription Factor 2

Epithelial-to-mesenchymal transition (EMT) is a key contributor to fibroblast activation in fibrosis of multiple organs, including the intestine. Parathyroid hormone-like hormone (PTHLH) is an important factor in renal fibrosis and regulates several processes, including EMT. Herein, we investigated the role of PTHLH-induced EMT in intestinal fibrosis associated with Crohn disease. The expression levels of the EMT-related proteins, PTHLH, and parathyroid hormone receptor 1 (PTH1R) in intestinal tissues were determined by immunohistochemistry, and our results revealed that PTHLH and PTH1R were significantly elevated and associated with EMT marker expression. Moreover, neutralizing PTH1R and antagonizing PTHLH bioactivity prevented transforming growth factor-β1-induced EMT. PTH1R can propagate the protein kinase A (PKA) signal and activate downstream nuclear transcription factors, including runt-related transcription factor 2 (Runx2). In addition, lentiviral vector-PTHLH-treated mice were highly sensitive to 2,4,6-trinitrobenzene sulfonic acid, and analysis of the PTHLH-PTH1R axis revealed the involvement of PKA-Runx2 in PTHLH-induced EMT. Our results indicate that PTHLH triggered EMT in intestinal epithelial cells through the PKA-Runx2 pathway, which might serve as a therapeutic target for intestinal fibrosis in Crohn disease.

Susceptibility genes and serum markers of intestinal fibrosis in Crohn disease

Crohn disease (CD) is a chronic inflammatory disease which progressively affects the digestive tract with unknown etiology. During the disease course, intestinal fibrosis will gradually develop in many CD patients and results in irreversible fibrosis stricture, causing refractory abdominal pain and even intestinal obstruction, and necessitating one or more surgical interventions. Thus far the exact etiology of CD remains unknown. It is believed that genetic, environmental and immunologic factors are involved, which may also predict the development of intestinal fibrosis. Recent studies have found the association of mutations in genes, such as NOD2, ATG16L1, CX3CR1, IL-23R and MMP3 with the fibrogenic phenotype of CD. In addition, serum extracellular matrix molecules, growth factors, miRNAs and microbial antibodies have also been linked to the fibrogenesis in CD patients, however the results of researches were divergent. Therefore it is of significance to explore noninvasive markers of intestinal fibrosis with high sensitivity and specificity, and the high-throughput proteomic technique may be an approach that deserves further investigation. Screening the high-risk patients for the fibrostenotic phenotype of CD by susceptibility genes, and early detection of intestinal fibrosis using noninvasive serum markers, will help improve the treatment outcomes and reduce the surgical rates. The article aims at summarizing the current susceptibility genes and serum markers of intestinal fibrosis in CD.

Crohn's disease-associated mucosal factors regulate the expression of TNF-like cytokine 1A and its receptors in primary subepithelial intestinal myofibroblasts and intestinal epithelial cells

Intestinal subepithelial myofibroblasts (SEMFs) exert a profibrotic role in Crohn's disease (CD). Tumor necrosis factor-like cytokine 1A (TL1A) and its receptors, death-domain receptor 3 (DR3) and decoy receptor 3 (DcR3), are mucosal factors with significant involvement in experimental inflammation and CD. We aimed to determine the regulation of expression of this system of proteins in SEMFs and intestinal epithelial cells. The relative amount of mRNA transcripts for TL1A, DR3, and DcR3 was measured by real-time reverse transcription polymerase chain reaction in cultured primary SEMFs, colonic myofibroblast cell line 18CO, and epithelial cell line HT29. Protein expression was determined by immunofluorescence. The effect of various proinflammatory stimuli in mRNA and protein expression was studied. TL1A mRNA and protein expression in primary SEMFs (and 18CO cells) was significantly upregulated after stimulation with interleukin 1-alpha and/or tumor necrosis factor alpha (TNF-α) (32- to 44-fold increase, P<0.05 vs unstimulated). Following stimulation with interleukin 1-alpha + TNF-α + IFN-γ, HT-29cells highly expressed DR3 (4.1-fold over unstimulated, P=0.008) and DcR3 (56-fold, P=0.009) and secreted soluble factors that led to induction of TL1A mRNA in primary SEMFs (28-fold, P=0.008). Activated epithelial cells significantly upregulated IL-8 expression in response to stimulation with recombinant TL1A. Supernatants from mucosal cultures of patients with CD were able to stimulate theexpression of TL1A in cultured primary SEMFs, in comparison to supernatants from healthy controls (3.8-fold increase, P<0.05) or culture media alone (P<0.05). In conclusion, we found that proinflammatory cytokines are important regulators ofthe expression of TL1A in SEMFs and of its receptors in intestinal epithelial cells. Our results raise the possibility for involvement of TL1A/DR3/DR3-mediated mechanismsin epithelial-mesenchymal interactions and the development of inflammation-induced intestinal fibrosis in CD.

In Crohn's disease fibrosis-reduced expression of the miR-29 family enhances collagen expression in intestinal fibroblasts

Intestinal fibrosis with stricture formation is a complication of CD (Crohn's disease) that may mandate surgical resection. Accurate biomarkers that reflect the relative contribution of fibrosis to an individual stricture are an unmet need in managing patients with CD. The miRNA-29 (miR-29) family has been implicated in cardiac, hepatic and pulmonary fibrosis. In the present study, we investigated the expression of miR-29a, miR-29b and miR-29c in mucosa overlying a stricture in CD patients (SCD) paired with mucosa from non-strictured areas (NSCD). There was significant down-regulation of the miR-29 family in mucosa overlying SCD compared with mucosa overlying NSCD. miR-29b showed the largest fold-decrease and was selected for functional analysis. Overexpression of miR-29b in CD fibroblasts led to a down-regulation of collagen I and III transcripts and collagen III protein, but did not alter MMP (matrix metalloproteinase)-3, MMP-12 and TIMP (tissue inhibitor of metalloproteinase)-1 production. TGF (transforming growth factor)-β1 up-regulated collagen I and III transcripts and collagen III protein as a consequence of the down-regulation of miR-29b, and TGF-β1-induced collagen expression was reversed by exogenous overexpression of miR-29b. Furthermore, serum levels of miR-29 were lower in patients with stricturing disease compared with those without. These findings implicate the miR-29 family in the pathogenesis of intestinal fibrosis in CD and provide impetus for the further evaluation of the miR-29 family as biomarkers.

Involvement of interleukin-17A-induced expression of heat shock protein 47 in intestinal fibrosis in Crohn's disease

ObjectiveIntestinal fibrosis is a clinically important issue in Crohn's disease (CD). Heat shock protein (HSP) 47 is a collagen-specific molecular chaperone involved in fibrotic diseases. The molecular mechanisms of HSP47...

Effect of moxibustion on expressions of TGF-β and Smad4 in colonic mucosa of rats with intestinal fibrosis in Crohn disease

Objective To observe the effect of moxibustion on the expressions of transforming growth factor-β (TGF-β) protein, and Smad4 protein and mRNA in rats with intestinal fibrosis in Crohn disease (CD), and to discuss the action mechanism of acupuncture-moxibustion in treating intestinal fibrosis in CD from the perspective of TGF-β/Smads signal pathway.

MiR-200b is involved in intestinal fibrosis of Crohn’s disease

Intestinal fibrosis is one of the major serious complications of Crohn’s disease (CD). However, there are no effective antifibrotic drugs to treat intestinal fibrosis in CD. Therefore, it is important to understand the pathogenesis of fibrosis in CD. It has been reported that members of the miR-200 family are essential in the regulation of renal fibrogenesis. In this study, we analyzed the function of miR-200a and miR-200b in intestinal fibrosis, which was induced by transforming growth factor β1 (TGF-β1) in vitro. Furthermore, we detected the expression of miR-200a and miR-200b in CD specimens, which were divided into groups of fibrosis and no-fibrosis. The results of this study showed that administration of miR-200b could partially protect intestinal epithelial cells from fibrogenesis in vitro. Furthermore, we found that miR-200b was overexpressed in the serum of the fibrosis group. The results suggest that miR-200b has potential value for diagnostic and therapeutic applications for CD patients with fibrosis complications.

Acupuncture on the basic fibroblast growth factor and type I collagen in colons of rats with Crohn’s disease

To observe the impacts of herb-partitioned moxibustion, warm moxibustion and electroacupuncture on the basic fibroblast growth factor (bFGF) and collagen type I (Col I) in colons of rats with Crohn’ disease (CD), and discuss the mechanism of acupuncture therapy on the intestinal fibrosis in CD. The model rats were developed by TNBS as multiple proinflammatory method. The rats were randomly divided into 5 groups: a normal group, a model group, a warm moxibustion group, an electroacupuncture group and a herb-partitioned moxibustion group. The treatments were carried out at Tianshu (ST 25) (bilateral) and Qihai (CV 6) in different treatments. The immunohistochemistry was used to detect the expression position of Col I and bFGF. The expressions of Col I and bFGF in colons of rats in the model group significantly increased (compared with the normal group, P<0.01). After the herb-partitioned moxibustion, warm moxibustion and electroacupuncture, the expressions of Col I and bFGF reduced markedly in the rats with CD (P<0.01). The expression of bFGF and Col Iin the colons had an obvious correlation in the Spearman rank correlation analysis. Acupuncture treatment reduced the abnormally high levels of expressions for Col I and bFGF in colons. Col I and bFGF participated in the fibrosis. Acupuncture treatment may reduce the bFGF expression in colons to regulate the excessive deposition, treating the intestinal fibrosis in CD.