Treatment Of Intestinal Fibrosis Research Articles

The Diagnosis of Intestinal Fibrosis in Crohn's Disease-Present and Future.

Crohn's disease (CD) progresses with periods of remission and exacerbations. During exacerbations, chronic inflammation leads to tissue destruction. As a result, intestinal fibrosis may develop in response to the ongoing inflammatory process. Fibrosis in CD should be considered the result of the response of the intestinal wall (over) to the presence of inflammation in the deep structures of the intestinal wall. In the absence of ideal noninvasive methods, endoscopic evaluation in combination with biopsy, histopathological analysis, stool analysis, and blood analysis remains the gold standard for assessing both inflammation and fibrosis in CD. On the contrary, the ability to identify markers of intestinal fibrosis would help to develop new diagnostic and therapeutic methods to detect early stages of fibrosis. It is speculated that miRNAs may, in the future, become biomarkers for early noninvasive diagnosis in the treatment of intestinal fibrosis. The purpose of this review is to summarise existing diagnostic methods for Crohn's disease and present recent scientific reports on molecular testing.

Mechanisms and therapeutic research progress in intestinal fibrosis.

Intestinal fibrosis is a common complication of chronic intestinal diseases with the characteristics of fibroblast proliferation and extracellular matrix deposition after chronic inflammation, leading to lumen narrowing, structural and functional damage to the intestines, and life inconvenience for the patients. However, anti-inflammatory drugs are currently generally not effective in overcoming intestinal fibrosis making surgery the main treatment method. The development of intestinal fibrosis is a slow process and its onset may be the result of the combined action of inflammatory cells, local cytokines, and intestinal stromal cells. The aim of this study is to elucidate the pathogenesis [e.g., extracellular matrix (ECM), cytokines and chemokines, epithelial-mesenchymal transition (EMT), differentiation of fibroblast to myofibroblast and intestinal microbiota] underlying the development of intestinal fibrosis and to explore therapeutic advances (such as regulating ECM, cytokines, chemokines, EMT, differentiation of fibroblast to myofibroblast and targeting TGF-β) based on the pathogenesis in order to gain new insights into the prevention and treatment of intestinal fibrosis.

Natural compound fraxinellone ameliorates intestinal fibrosis in mice via direct intervention of HSP47-collagen interaction in the epithelium.

Intestinal fibrosis is a common complication of inflammatory bowel disease. There is still a lack of effective drugs for the prevention or treatment of intestinal fibrosis. Heat shock protein 47 (HSP47) plays a key role in the development of intestinal fibrosis. In this study we investigated the therapeutic potential and underlying mechanisms of fraxinellone, a degraded limonoid isolated from the root bark of Dictamnus dasycarpus, in the treatment of intestinal fibrosis. Intestinal fibrosis was induced in mice by dextran sodium sulfate (DSS) treatment. DDS-treated mice were administered fraxinellone (7.5, 15, 30 mg·kg-1·d-1, i.g.) for 45 days. We showed that fraxinellone administration dose-dependently alleviated DSS-induced intestinal impairments, and reduced the production of intestinal fibrosis biomarkers such as α-smooth muscle actin (SMA), collagen I, hydroxyproline, fibronectin and laminin, and cytokines such as TGF-β, TNF-α and IL-β. We then established in vitro intestinal fibrosis cell models in SW480 and HT-29 cells, and demonstrated that treatment with fraxinellone (3, 10, 30 μM) significantly relieved TGF-β-induced fibrosis responses by inhibiting the TGF-β/Smad2/3 signaling pathway. Molecular docking suggested that the fraxinellone might disrupt the interaction between HSP47 and collagen, which was confirmed by coimmunoprecipitation experiments. SPR analysis showed that fraxinellone had a high affinity for HSP47 with a Kd value of 3.542 × 10-5 M. This study provides a new example of HSP47-collagen intervention by a natural compound and has important implications for the clinical treatment of inflammation-induced issue fibrosis.

Gut Microbiota, Macrophages and Diet: An Intriguing New Triangle in Intestinal Fibrosis.

Intestinal fibrosis is a common complication in inflammatory bowel disease (IBD) without specific treatment. As macrophages are the key actors in inflammatory responses and the wound healing process, they have been extensively studied in chronic diseases these past decades. By their exceptional ability to integrate diverse stimuli in their surrounding environment, macrophages display a multitude of phenotypes to underpin a broad spectrum of functions, from the initiation to the resolution of inflammation following injury. The hypothesis that distinct macrophage subtypes could be involved in fibrogenesis and wound healing is emerging and could open up new therapeutic perspectives in the treatment of intestinal fibrosis. Gut microbiota and diet are two key factors capable of modifying intestinal macrophage profiles, shaping their specific function. Defects in macrophage polarisation, inadequate dietary habits, and alteration of microbiota composition may contribute to the development of intestinal fibrosis. In this review, we describe the intriguing triangle between intestinal macrophages, diet, and gut microbiota in homeostasis and how the perturbation of this discreet balance may lead to a pro-fibrotic environment and influence fibrogenesis in the gut.

Challenges in the Pathophysiology, Diagnosis, and Management of Intestinal Fibrosis in Inflammatory Bowel Disease

Intestinal fibrosis is a common complication of inflammatory bowel disease (IBD) that is usually the consequence of chronic inflammation. Although the currently available anti-inflammatory therapies have had little impact on intestinal fibrosis in Crohn's disease (CD), increased understanding of the pathophysiology and the development of therapies targeting fibrogenic pathways hold promise for the future. One of the critical challenges is how reduction or reversal of intestinal fibrosis should be defined and measured in the setting of clinical trials and drug approval. The International Organization for Inflammatory Bowel Disease (IOIBD) organized a workshop in Amsterdam, The Netherlands, on December 19th and 20th, 2018 in an attempt to review the current knowledge of the biological background, diagnosis, treatment of intestinal fibrosis and clinical trial endpoints. Basic and clinical scientists discussed the pathophysiology of intestinal fibrosis, the current status of biomarkers and imaging modalities in stenosing CD, and recent clinical studies in this area. Researchers from outside of the IBD field presented advances in the understanding of fibrotic processes in other organs, such as the skin, liver and lungs. Lastly, the design of clinical trials with antifibrotic therapy for IBD was discussed, with priority on patient populations, patient reported outcomes (PROs) and imaging. This report summarizes the key findings, discussions and conclusions of the workshop.

Inhibiting Interleukin 36 Receptor Signaling Reduces Fibrosis in Mice With Chronic Intestinal Inflammation

Intestinal fibrosis is a long-term complication in inflammatory bowel diseases (IBD) that frequently results in functional damage, bowel obstruction, and surgery. Interleukin (IL) 36 is a group of cytokines in the IL1 family with inflammatory effects. We studied the expression of IL36 and its receptor, interleukin 1 receptor like 2 (IL1RL2 or IL36R) in the development of intestinal fibrosis in human tissues and mice. We obtained intestinal tissues from 92 patients with Crohn's disease (CD), 48 patients with ulcerative colitis, and 26 patients without inflammatory bowel diseases (control individuals). Tissues were analyzed by histology to detect fibrosis and by immunohistochemistry to determine the distribution of fibroblasts and levels of IL36R ligands. Human and mouse fibroblasts were incubated with IL36 or control medium, and transcriptome-wide RNA sequences were analyzed. Mice were given neutralizing antibodies against IL36R, and we studied intestinal tissues from Il1rl2-/- mice; colitis and fibrosis were induced in mice by repetitive administration of DSS or TNBS. Bone marrow cells were transplanted from Il1rl2-/- to irradiated wild-type mice and intestinal tissues were analyzed. Antibodies against IL36R were applied to mice with established chronic colitis and fibrosis and intestinal tissues were studied. Mucosal and submucosal tissue from patients with CD or ulcerative colitis had higher levels of collagens, including type VI collagen, compared with tissue from control individuals. In tissues from patients with fibrostenotic CD, significantly higher levels of IL36A were noted, which correlated with high numbers of activated fibroblasts that expressed α-smooth muscle actin. IL36R activation of mouse and human fibroblasts resulted in expression of genes that regulate fibrosis and tissue remodeling, as well as expression of collagen type VI. Il1rl2-/- mice and mice given injections of an antibody against IL36R developed less severe colitis and fibrosis after administration of DSS or TNBS, but bone marrow cells from Il1rl2-/- mice did not prevent induction of colitis and fibrosis. Injection of antibodies against IL36R significantly reduced established fibrosis in mice with chronic intestinal inflammation. We found higher levels of IL36A in fibrotic intestinal tissues from patients with IBD compared with control individuals. IL36 induced expression of genes that regulate fibrogenesis in fibroblasts. Inhibition or knockout of the IL36R gene in mice reduces chronic colitis and intestinal fibrosis. Agents designed to block IL36R signaling could be developed for prevention and treatment of intestinal fibrosis in patients with IBD.

Transforming growth factor β1-induced collagen production in myofibroblasts is mediated by reactive oxygen species derived from NADPH oxidase 4

Intestinal fibrosis with stricture formation is a severe complication of Crohn's disease (CD). Though new therapeutic targets to enable the prevention or treatment of intestinal fibrosis are needed, markers of this condition and the basic mechanisms responsible have not been established. NADPH oxidase (NOX) 4 has already been reported to play a key role in models of fibrogenesis, including that of the lung. However, its importance in intestinal fibrogenesis remains unclear. In this study, we examined the role of NOX4 in collagen production by intestinal myofibroblasts stimulated with transforming growth factor (TGF)-β1. Using LmcMF cells, an intestinal subepithelial myofibroblast (ISEMF) line, we first examined the induction of collagen production by TGF-β1. Subsequently, we investigated the role of NOX4 in TGF-β1-induced collagen I production in these cells using SB525334 (an SMAD2/3 inhibitor), diphenyleneiodonium (an NOX inhibitor), and Nox4 small interfering RNA (siRNA). Production of collagen was assessed with Sirius red staining, and Nox4 expression was measured by quantitative real-time PCR. Reactive oxygen species (ROS) production was determined using DCFDA and fluorescent microscopy. We observed that TGF-β1 induced collagen production via NOX4 activation and ROS generation in LmcMF cells. Nox4 siRNA and inhibitors of TGF-β1 receptor and NOX significantly reduced TGF-β1-induced ROS and collagen production. Thus, in the present study, we revealed that collagen production in ISEMFs is induced via an NOX4-dependent pathway. This work supports a function for NOX4 in intestinal fibrogenesis and identifies it as a potential therapeutic target in recalcitrant fibrotic disorders of CD patients.

Treatment of Intestinal Fibrosis in Experimental Inflammatory Bowel Disease by the Pleiotropic Actions of a Local Rho Kinase Inhibitor

Intestinal fibrosis resulting in (sub)obstruction is a common complication of Crohn's disease (CD). Rho kinases (ROCKs) play multiple roles in TGFβ-induced myofibroblast activation that could be therapeutic targets. Because systemic ROCK inhibition causes cardiovascular side effects, we evaluated the effects of a locally acting ROCK inhibitor (AMA0825) on intestinal fibrosis. Fibrosis was assessed in mouse models using dextran sulfate sodium (DSS) and adoptive T-cell transfer. The invitro and exvivo effects of AMA0825 were studied in different cell types and in CD biopsy cultures. ROCK is expressed in fibroblastic, epithelial, endothelial, and muscle cells of the human intestinal tract and is activated in inflamed and fibrotic tissue. Prophylactic treatment with AMA0825 inhibited myofibroblast accumulation, expression of pro-fibrotic factors, and accumulation of fibrotic tissue without affecting clinical disease activity and histologic inflammation in 2 models of fibrosis. ROCK inhibition reversed established fibrosis in a chronic DSS model and impeded exvivo pro-fibrotic protein secretion from stenotic CD biopsies. AMA0825 reduced TGFβ1-induced activation of myocardin-related transcription factor (MRTF) and p38 mitogen-activated protein kinase (MAPK), down-regulating matrix metalloproteinases, collagen, and IL6 secretion from fibroblasts. In these cells, ROCK inhibition potentiated autophagy, which was required for the observed reduction in collagen and IL6 production. AMA0825 did not affect pro-inflammatory cytokine secretion from other ROCK-positive cell types, corroborating the selective invivo effect on fibrosis. Local ROCK inhibition prevents and reverses intestinal fibrosis by diminishing MRTF and p38 MAPK activation and increasing autophagy in fibroblasts. Overall, our results show that local ROCK inhibition is promising for counteracting fibrosis as an add-on therapy for CD.

Features of intestinal lesions in the clinical course of inflammatory bowel diseases.

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), are chronic, progressive and relapsing inflammatory disorders of unknown etiology. UC is characterized by inflammation of the large bowel mucosa and submucosa, whereas in CD inflammation is transmural and may involve various sites of the gastrointestinal tract. Superficial mucosal lesions are most prone to heal, whereas deep ulcers or transmural fissures may heal with more difficulty and may be followed by the development of fibrosis and strictures requiring surgery. Inflammation appears to be necessary to trigger the onset of the fibrotic process, but subsequently plays a minor role in its progression. In IBD, anti-inflammatory treatment does not prevent evolution of fibrosis once the process has started. Therefore, the mechanisms that regulate fibrosis appear to be distinct from those regulating inflammation. Intestinal fibrosis is due to an abnormal accumulation of extracellular matrix proteins producted by activated intestinal myofibroblasts. Increased evidence indicate that a number of molecules are involved in the development of the disease and a crosstalk between TGFbeta/Smads pathway and alphavbeta6 integrin, mTOR and PPARgamma could play a crucial role in the development of intestinal fibrosis. Animal models represent a useful tool to investigate the molecular and cellular mechanisms of intestinal inflammation and fibrosis and to test the effectiveness of novel therapeutic strategies for the prevention and treatment of intestinal fibrosis that still remain the major cause of surgical intervention.

A New Heterotopic Transplant Animal Model of Intestinal Fibrosis

Severe mucosal tissue damage requiring efficient wound healing is a main feature of inflammatory bowel disease but excessive tissue repair promotes fibrosis. The clinical investigation of fibrosis is confined to the limited amount of biological material available from patients. This makes the establishment of a new animal model, a highly desirable goal. We investigated whether intestinal fibrosis occurs after heterotopic transplantation of small bowel resections in rats. Donor (Brown Norway or Lewis rats) small bowel resections were transplanted subcutaneously into the neck of recipients (Lewis rats). Grafts were explanted 2, 7, 14, and 21 days after transplantation. Heterotopic intestinal transplants remained viable for 21 days. Rapid loss of crypt structures at day 2 after intestinal transplantation was followed by lymphocyte infiltration and obliteration of the intestinal lumen by fibrous tissue at day 21. Loss of the intestinal epithelium was confirmed by the lack of cytokeratin staining in immunohistochemistry. Collagen expression was increased with time after transplantation as confirmed by real-time PCRs, Elastica van Gieson, and Sirius Red staining. Lumen obliteration was connected with increased expression of potent mediators of fibrosis such as α5β6 integrin, interleukin (IL)-13, and transforming growth factor β. Myofibroblast phenotype was demonstrated by the presence of both α-smooth muscle actin and vimentin in the obliterated lumen. We established a method for heterotopic transplantation of small bowel resections. A variety of histologic and molecular features of fibrosis were observed in the heterotopic intestinal grafts which suggests, that this new in vivo model will be instrumental in studying pathogenesis and treatment of intestinal fibrosis.

The effect of Adiponectin on Intestinal Fibroblasts

Intestinal fibrosis is a common complication of inflammatory bowel disease ((IBD), dysregulated intestinal inflammation with an unknown etiology). During fibrosis, over‐active fibroblasts produce aberrant collagen, which leads to the formation of fistulas, intestinal strictures, and bowel obstructions. Adiponectin (APN), a member of the C1q/Tumor necrosis factor related proteins (CTRP), is a cytokine that is released by adipocytes and is reported as having a dual role in metabolism and immunity. Interestingly, intestinal fibrosis patients have increased levels of APN and IL‐6 (inflammatory, pro‐fibrotic cytokine). For this study, we examined the effect that APN exerts on intestinal fibroblasts. Results show that the expression of the APN receptor on fibroblasts was varied with treatment of IL‐6, IL‐10 (anti‐inflammatory cytokine) and interferon‐γ (inflammatory cytokine), and co‐immunoprecipitation results reveal that the APN receptor is linked to CD11b on the fibroblast surface. Furthermore, cellular treatment with APN caused increased adhesion of fibroblasts to type I collagen and facilitated the release IL‐6 in a concentration dependent manner. Results identify a mechanism that is initially mediated by APN, and potentially may lead to a hyper fibro proliferative‐phenotype indicative of fibrosis. This study highlights APN as a potential target molecule in the treatment of intestinal fibrosis.

P056 GED-0507–34 Levo, a novel modulator of PPARgamma as new therapeutic strategy in the treatment of intestinal fibrosis

protein were collected. Cytokine levels in cell supernatants were determined using the Bioplex 3D suspension array system (Bio-Rad). Preadipocyte supernatants were also applied on cultures of human colonic NCM-460 cells for 24hs and RNA and protein were collected. Inflammatory molecule mRNA expression and activation of intracellular kinases were evaluated with Luminex inflammatory panels (FlexScript LDA), and phospho-protein multiplex panels, respectively. Results: Preadipocytes isolated from IBD patients demonstrated differential mediator secretion patterns compared to preadipocytes from control and obese patients. Of the 42 proinflammatory cytokines and growth factors tested, IL-7/IL-8/Gro/MCP3/VEGF/ PDGF-AA showed statistically significant differences between control, obese and IBD preadipocytes (p ,0.05). Notably, there were significant differences in mediator secretion between preadipocytes isolated from UC and CD patients, in particular VEGF and PDGF (p , 0.01 for both). NCM-460 cells had distinct GSK-3, AKT kinase activation (p , 0.05 for both) and cytokine mRNA expression patterns of TNF, IL-2, IL-3, IL-17, VEGF, MIP-1 β, MIP-3, RANTES (p,0.05) following exposure to preadipocyte supernatants from all three pathological conditions compared to controls. Conclusions: Our data suggest the existence of preadipocyte-disease-dependent mediators contributing to the generation of differential colonocyte responses. Together with reports indicating altered levels of several adipokines during IBD, our results provide the first direct evidence for the importance of adipose tissue homeostasis during obesity in determining the outcome of IBD. Supported by NIH P50 DK064539 (CP & IK), DK047343, DK060729 (CP), The Broad Foundation (BMRP) (IK, RA), and the Blinder Research Foundation for Crohn's Disease (AS).

Treatment of Intestinal Fibrosis With Tocotrienols in an Optimized Rat Model

Treatment of Intestinal Fibrosis With Tocotrienols in an Optimized Rat Model

Simvastatin impairs smad-3 phosphorylation and modulates transforming growth factor β1-mediated activation of intestinal fibroblasts

Transforming growth factor (TGF) beta1, acting through the smad pathway, is critical to fibroblast-mediated intestinal fibrosis. Simvastatin exhibits antifibrotic properties. This study assessed the effects of simvastatin on TGF-beta1-mediated intestinal fibroblast activation. Human intestinal fibroblasts were activated with TGF-beta1 with or without simvastatin or the cholesterol pathway intermediates farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). Collagen-Ialpha2 expression was assessed by reverse transcriptase-polymerase chain reaction. Connective tissue growth factor (CTGF) and smad phosphorylation were evaluated by western blot, and plasminogen activator inhibitor (PAI) 1 activity by enzyme-linked immunosorbent assay. Fibroblast filamentous (F)-actin accumulation was assessed by confocal microscopy and contraction by a fibroblast-populated collagen lattice (FPCL) model. TGF-beta1 treatment of fibroblasts induced smad-2/3 phosphorylation, CTGF and collagen-Ialpha2 production, F-actin bundling, FPCL contraction and PAI-1 activation. Pretreatment with simvastatin inhibited the induction of CTGF and collagen-Ialpha2, PAI-1 activation, F-actin bundling and FPCL contraction. The inhibitory effect of simvastatin on PAI-1 activation was reversed by GGPP and FPP. Simvastatin pretreatment inhibited TGF-beta1-mediated phosphorylation of smad-3. Simvastatin abrogates TGF-beta1-mediated intestinal fibroblast activation by inhibition of smad-3 phosphorylation. These findings offer a mechanism for the antifibrotic effects of simvastatin and a therapeutic entry point in the treatment of intestinal fibrosis.

Prevention and treatment of intestinal fibrosis: up‐regulate smad7 or inhibit smad3 expression?

Prevention and treatment of intestinal fibrosis: up‐regulate smad7 or inhibit smad3 expression?

Clinical study on the prevention and treatment of intestinal fibrosis in ulcerative colitis by moxibustion

Objective To observe the therapeutic effects and action mechanism of moxibustion in the treatment of intestinal fibrosis in ulcerative colitis.Methods Tianshu (ST25) and Qihai (CV6) were the main acupoint; other points were used according to syndrome differentiation. Sixty-five patients were randomized into two groups: Group A in which 32 cases were treated by herbpartitioned moxibustion and group B in which 33 cases were treated by bran-partitioned moxibustion. The therapeutic effects and TGF-β1, I and III collagen expressions were measured before and after treatment.Results In group A, 17 cases were cured, 12 cases improved and 3 failed; in group B, 11 cases were cured, 16 cases improved and 6 cases failed. I, III collagen expressions were obviously inhibited in the two groups, in group A in particular.Conclusion In the prevention and treatment of intestinal fibrosis, moxibustion may reduce the expression of TGF-β1, and hence to block or inhibit the synthesis of I, III collagens, and improve the structure and function.