Increased collagen type III synthesis by fibroblasts isolated from strictures of patients with Crohn's disease

Aspergillus awamori: potential antioxidant, anti-inflammatory, and anti-apoptotic activities in acetic acid-induced ulcerative colitis in rats

Ulcerative colitis (UC) is a chronic colonic inflammation with a significant health hazard. Aspergillus awamori (A. awamori) is a microorganism with various bioactive compounds with natural antioxidant and anti-inflammatory properties. The present work aimed to elucidate the protective and therapeutic effects of varying concentrations of A. awamori against acetic acid (AA)-induced ulcerative colitis (UC) in rats. Nine groups of albino male rats were established: a control negative group (G1), a control positive group (G2,AA), and preventive protocol groups (including G3A, G4A, and G5A) that received 100 mg, 50 mg, and 25 mg/kg b.w, respectively, of A. awamori orally and daily from the 1st day of the experiment and for 7 consecutive days. Then, they were subjected to one dose of AA intrarectally on day 8th. G3B, G4B, and G5B were termed as curative protocol groups that received one dose of AA on day 8th and then administered 100 mg, 50 mg, and 25 mg/kg b.w. of A. awamori, respectively, on day 9th and continued receiving these doses daily until day 16th. Rats in the AA group exhibited marked histopathological alterations of the distal colon, with an exaggeration of the DAI. In addition, a remarkable increase in oxidative stress was represented by the elevation of MDA and NO levels with a decline in SOD and GPx activities. In addition, upregulation of TNF-α, IL-6, and IL-1β mRNA expressions and downregulation of Muc2 and Nrf2 levels were detected. Unambiguously, a remarkable anti-inflammatory effect was noticed either in A. awamori prevented or treated groups expounded by reducing and regulating TNF-α, IL-6, and IL-1β with improved pathological lesion scoring. The Muc2, Nrf2, and bcl-2 gene levels were upregulated and restored also. In summary, the findings in this work reveal that A. awamori supplementation successfully alleviated the UC induced by AA, which had a better effect when administered before colitis induction.

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

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

Single Nucleotide Polymorphisms of the MEFV Gene E148Q Are Highly Associated With Disease Phenotype in Crohn's Disease

BACKGROUND

Single nucleotide polymorphisms (SNPs) of the MEFV gene may modify inflammatory bowel disease (IBD) activity. The prevalence of MEFV gene SNPs in IBD patients and their involvement in IBD pathophysiology remains unclear.

METHODS

We analyzed 12 MEFV gene SNPs in peripheral leukocytes of Japanese IBD patients (Crohn's disease [CD]: 69 patients, ulcerative colitis: 32 patients) by polymerase chain reaction using next-generation DNA sequencing and evaluated their prevalence and association with the disease characteristics. Inflammasome activity and mature interleukin (IL)-1β and IL-18 production were evaluated in peripheral blood mononuclear cells obtained from CD patients stimulated with lipopolysaccharides and adenosine triphosphate, and compared between those with and without the E148Q SNP. COL1A1 and HSP47 gene expression was analyzed in CCD-18Co cells costimulated with IL-1β and other inflammatory cytokines.

RESULTS

The prevalence of MEFV gene SNPs in IBD patients was similar to that in the human gene database. E148Q was the most common SNP. Compared with CD patients without E148Q, those with E148Q had a significantly greater frequency of the stricture phenotype, and their peripheral blood mononuclear cells exhibited significantly higher IL-1β and IL-18 levels and higher caspase-1 activity. IL-1β and IL-17A synergistically increased COL1A1 and HSP47 gene expression.

CONCLUSIONS

MEFV gene SNPs, including E148Q, modify the behavior of CD. IL-1β and IL-18 are produced through enhanced caspase-1 activity in monocytes of CD patients with E148Q. IL-1β promotes gene expression of fibrosis-related genes by cooperating with IL-17A in myofibroblasts. Therefore, E148Q might be a disease-modifying gene associated with the fibrostenosis phenotype in CD patients.

Fibrosis-related transcriptome unveils a distinctive remodeling matrix pattern in penetrating ileal Crohn's disease

BACKGROUND AND AIMS

Stricturing (B2) and penetrating (B3) ileal Crohn's disease have been reported to present similar levels of histopathological transmural fibrosis. This study aimed to compare the fibrosis-related transcriptomic profiles of penetrating and stricturing ileal Crohn's disease.

METHODS

Using Nanostring technology and comparative bioinformatics, we analyzed the expression of 787 fibrosis-related genes in 36 ileal surgical specimens, 12 B2 and 24 B3, the latter including 12 cases with associated stricture(s) (B3s) and 12 without (B3o). Quality control of extracted RNA was performed according to Nanostring parameters and principal component analysis for the distribution analysis. For the selection of the differentially expressed genes a p-adjusted <0.05 and Fold Change ≤-1.5 or ≥ 1.5 was adopted. qPCR and immunohistochemistry analyses were used to validate selected differentially expressed genes.

RESULTS

We included 34 patients with B2 and B3 phenotypes, balanced for age at diagnosis, age at surgery, gender, Crohn's disease localization, perianal disease and therapy. Inflammation and fibrosis histopathological scoring were similar in all cases. B2 and B3 groups showed a very good clustering regarding 30 significantly differentially expressed genes, all being remarkably upregulated in B3. More than half of these genes were involved in Crohn's disease fibrogenesis, while eight differentially expressed genes were so in other organs. The most significantly active biologic processes and pathways in penetrating disease were response to TGFβand matrix organization and degradation, as validated by immunohistochemistry.

CONCLUSIONS

Despite the histopathological similarities in fibrosis between stricturing and penetrating ileal Crohn's disease, their fibrosis-related transcriptomic profiles are distinct. Penetrating disease exhibits a distinctive transcriptomic landscape related to enhanced matrix remodeling.

Serum TGF-β1 and CD14 Predicts Response to Anti-TNF-α Therapy in IBD

Background

Tumor necrosis factor-alpha (TNF-α) agonists revolutionized therapeutic algorithms in inflammatory bowel disease (IBD) management. However, approximately every third IBD patient does not respond to this therapy in the long term, which delays efficient control of the intestinal inflammation.

Methods

We analyzed the power of serum biomarkers to predict the failure of anti-TNF-α. We collected serum of 38 IBD patients at therapy prescription and 38 weeks later and analyzed them with relation to therapy response (no-, partial-, and full response). We used enzyme-linked immunosorbent assay to quantify 16 biomarkers related to gut barrier (intestinal fatty acid-binding protein, liver fatty acid-binding protein, trefoil factor 3, and interleukin (IL)-33), microbial translocation, immune system regulation (TNF-α, CD14, lipopolysaccharide-binding protein, mannan-binding lectin, IL-18, transforming growth factor-β1 (TGF-β1), osteoprotegerin (OPG), insulin-like growth factor 2 (IGF-2), endocrine-gland-derived vascular endothelial growth factor), and matrix metalloproteinase system (MMP-9, MMP-14, and tissue inhibitors of metalloproteinase-1).

Results

We found that future full-responders have different biomarker profiles than non-responders, while partial-responders cannot be distinguished from either group. When future non-responders were compared to responders, their baseline contained significantly more TGF-β1, less CD14, and increased level of MMP-9, and concentration of these factors could predict non-responders with high accuracy (AUC = 0.938). Interestingly, during the 38 weeks, levels of MMP-9 decreased in all patients, irrespective of the outcome, while OPG, IGF-2, and TGF-β1 were higher in non-responders compared to full-responders both at the beginning and the end of the treatment.

Conclusions

The TGF-β1 and CD14 can distinguish non-responders from responders. The changes in biomarker dynamics during the therapy suggest that growth factors (such as OPG, IGF-2, and TGF-β) are not markedly influenced by the treatment and that anti-TNF-α therapy decreases MMP-9 without influencing the treatment outcome.

Xanthohumol Interferes with the Activation of TGF-β Signaling in the Process Leading to Intestinal Fibrosis

Fibrosis has various biological processes and affects almost every organ, especially in patients with inflammatory bowel disease, including Crohn's disease, who experience discomfort caused by intestinal fibrosis, which is a problem that needs to be resolved. TGF-β signaling is known to act as a key regulator of intestinal fibrosis, and its modulation could be an excellent candidate for fibrosis therapy. Xanthohumol (XN) has various effects, including anti-inflammation and anti-cancer; however, the detailed mechanism of TGF-β signaling has not yet been studied. The purpose of this study was to investigate the mechanism underlying the anti-fibrotic effect of XN on TGF-β1-induced intestinal fibrosis using primary human intestinal fibroblasts (HIFs). In this study, to check the anti-fibrotic effects of XN on intestinal fibrosis, we assessed the expression of fibrosis-related genes in TGF-β1-stimulated HIFs by qPCR, immunoblotting, and immunofluorescence staining. As a result, XN showed the ability to reduce the expression of fibrosis-associated genes increased by TGF-β1 treatment in HIFs and restored the cell shape altered by TGF-β1. In particular, XN repressed both NF-κB- and Smad-binding regions in the α-SMA promoter, which is important in fibrosis. In addition, XN inhibited NF-κB signaling, including phosphorylated-IkBα and cyclooxygenase-2 expression, and TNF-α-stimulated transcriptional activity of NF-κB. XN attenuated TGF-β1-induced phosphorylation of Smad2 and Smad3, and the transcriptional activity of CAGA. Particularly, XN interfered with the binding of TGF-Receptor I (TβRI) and Smad3 by binding to the kinase domain of the L45 loop of TβRI, thereby confirming that the fibrosis mechanism did not proceed further. In conclusion, XN has an inhibitory effect on TGF-β1-induced intestinal fibrosis in HIFs, significantly affecting TGF-β/Smad signaling.

Stem Cells from Healthy and Tendinopathic Human Tendons: Morphology, Collagen and Cytokines Expression and Their Response to T3 Thyroid Hormone

The aim of this study was to investigate the effect of triiodothyronine (T3) on tendon specific markers and cytokines expression of stem cells extracted from human tendons. Indeed, thyroid hormones have been reported to be protective factors, maintaining tendons' homeostasis, whereas tendinopathy is believed to be related to a failed healing response. Healthy and tendinopathic human tendons were harvested to isolate tendon stem/progenitor cells (TSPCs). TSPCs obtained from pathological samples showed gene expression and morphological modifications at baseline in comparison with cells harvested from healthy tissues. When cells were maintained in a medium supplemented with T3 (10-6 M), only pathological populations showed a significant upregulation of tenogenic markers (DCN, TNC, COL1A1, COL3A1). Immunostaining revealed that healthy cells constantly released type I collagen, typical of tendon matrix, whereas pathological ones overexpressed and secreted type III collagen, typical of scarred and impaired tissue. Pathological cells also overexpressed pro- and anti-inflammatory cytokines, suggesting an impaired balance in the presence of T3, without STAT3 activation. Moreover, DKK-1 was significantly high in the culture medium of pathological cell cultures and was reversed by T3. This study opens perspectives on the complex biochemical alteration of cells from pathological tendons, which may lead to the chronic disease context with an impaired extracellular matrix.

Surgical Management of Small Bowel Crohn's Disease

Crohn's disease in the small bowel could present itself as an inflammatory stricture, a fibrotic stricture as penetrating disease or a combination of both. It is pertinent to differentiate the disease process as well as its extent to effectively manage the disease. Currently, a combination of medical and surgical therapies forms part of the treatment plan while the debate of which therapy is better continues. In managing the strictures, identification of the disease process through imaging plays a pivotal role as inflammatory strictures respond to anti-tumor necrosis factor (TNF) and biological agents, while fibrotic strictures require endoscopic or surgical intervention. Recent evidence suggests a larger role for surgical excision, particularly in ileocolic disease, while achieving a balance between disease clearance and bowel preservation. Several adaptations to the surgical technique, such as wide mesenteric excision, side to side or Kono-S anastomosis, and long-term metronidazole therapy, are being undertaken even though their absolute benefit is yet to be determined. Penetrating disease requires a broader multidisciplinary approach with a particular focus on nutrition, skincare, and intestinal failure management. The current guidance directs toward early surgical intervention for penetrating disease when feasible. Accurate preoperative imaging, medical management of active diseases, and surgical decision-making based on experience and evidence play a key role in success.

IL-36γ and IL-36Ra Reciprocally Regulate Colon Inflammation and Tumorigenesis by Modulating the Cell-Matrix Adhesion Network and Wnt Signaling

Inflammatory bowel disease and colorectal cancer are associated with dysregulation of cytokine networks. However, it is challenging to target cytokines for effective intervention because of the overlapping functions and unpredictable interactions of cytokines in such diverse networks. Here, it is shown that IL-36γ and IL-36Ra, an agonist and an antagonist for IL-36R signaling respectively, reciprocally regulate the experimental colitis and the colon cancer development in mice. Knockout or neutralization of IL-36γ alleviates dextran sulfate sodium (DSS)-induced colitis and inhibits colon cancer development, whereas knockout of IL-36Ra exacerbates DSS-induced colitis and promotes colonic tumorigenesis in multiple colon cancer models in mice. Mechanistically, IL-36γ upregulates extracellular matrix and cell-matrix adhesion molecules and facilitates Wnt signaling, which is mitigated by IL-36Ra or IL-36γ neutralizing antibody. Consistently, IL-36γ levels are positively correlated with extracellular matrix levels and β-catenin levels in human colorectal tumor biopsies. These findings suggest the critical role of IL-36γ and IL-36Ra in gut inflammation and tumorigenesis and indicate that targeting the IL-36γ/IL-36Ra signal balance provides potential therapeutic strategy for inflammatory bowel disease and gastrointestinal cancers.

Diagnostic biomarkers of dilated cardiomyopathy

BACKGROUND

Dilated cardiomyopathy (DCM) is a condition involving dilation of cardiac chambers, which results in contraction impairment. Besides invasive and non-invasive diagnostic procedures, cardiac biomarkers are of great importance in both diagnosis and prognosis of the disease. These biomarkers are categorized into three groups based on their site; cardiomyocyte biomarkers, microenvironmental biomarkers and macroenvironmental biomarkers.

AIMS

In this review, an overview of characteristics, epidemiology, etiology and clinical manifestations of DCM is provided. In addition, the most important biomarkers, of all three categories, and their diagnostic and prognostic values are discussed.

CONCLUSION

Considering the association of DCM with conditions such as infections and autoimmunity, which are prevalent among the population, introducing efficient diagnostic tools is of high value for the early detection of DCM to prevent its severe complications. The three discussed classes of biomarkers are potential candidates for the detection of DCM. However, further studies are necessary in this regard.

Development of Anti-fibrotic Therapy in 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 anti-fibrotic 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 summarized data from randomized controlled trials (RCT) of anti-fibrotic therapies in these conditions. Multiple compounds have been tested for the anti-fibrotic effects in other organs. According to their mechanisms, they were categorized into growth factor modulators, inflammation modulators, 5-hydroxy-3-methylgultaryl-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.

Beyond biologics: advanced therapies in inflammatory bowel diseases

Inflammatory bowel diseases (IBDs) are conditions characterized by persistent and relapsing inflammation involving the gastrointestinal tract at various levels. Although the etiopathogenesis of IBDs is partially understood, a deregulated activation of intestinal immune cells in genetically susceptible patients is thought to be key for the disease onset and evolution. Artificial Nutrition might affect favorably on inflammation and related cytokine storm. However, the discovery of monoclonal antibodies blocking pro-inflammatory cytokines (e.g., tumor necrosis factor-α - TNF-α) changed radically the management of IBDs. Anti-TNF-α agents represent the prototype molecule of the so-called 'biologics' / 'biologicals'. These compounds have significantly improved the therapeutic management of IBDs refractory to standard medications, achieving clinical remission, mucosal healing and preventing extra-intestinal manifestations. However, about 50% of patients treated with biologicals experienced drawbacks, such as primary failure or loss of response, requiring new effective treatments. Translational studies have identified other pathways, different from the TNF-α blockade, and new molecules, e.g. sphingosine-1-phosphate agonists and the JAK kinase inhibitors, have been proposed as potential therapeutic options for IBDs. These novel therapeutic approaches represent a "new era" of IBD management, especially for patients poorly responsive to biologicals. In this review, we will summarize the new pharmacological strategies to treat IBDs, and discuss their effectiveness and safety, along with future perspectives for IBD treatment.

Intestinal Fibrosis and Gut Microbiota: Clues From Other Organs

Fibrosis is a complex and difficult to elucidate pathological process with no available therapies. Growing evidence implicates intestinal microbiota in the occurrence and development of fibrosis, and the potential mechanisms involved in different organs have been explored in several studies. In this review, we summarize the causative and preventive effects of gut microbiota on intestinal fibrosis, as well as the relationships between gut microbiota and fibrosis in other organs. Interestingly, several colonized microbes are associated with fibrosis via their structural components and metabolic products. They may also play essential roles in regulating inflammation and fibroblast activation or differentiation, which modulates extracellular matrix formation. While the relationships between intestinal fibrosis and gut microbiota remain unclear, lessons can be drawn from the effects of gut microbiota on hepatic, cardiac, nephritic, and pulmonary fibrosis. Various intestinal microbes alterations have been detected in different fibrotic organs; however, the results were heterogeneous. Mechanisms by which the intestinal microbiota regulate fibrotic processes in other organs, such as novel metabolic products or specific microbes, are also discussed. The specific microbiota associated with fibrosis in other organs could instruct future studies aiming to discover prospective mechanisms regulating intestinal fibrosis.

Distinctive roles of fibrillar collagen I and collagen III in mediating fibroblast-matrix interaction: A nanoscopic study

One major goal in tissue engineering is to create functional materials, mimicking scaffolds in native tissues, to modulate cell function for tissue repair. Collagen is the most abundant structural protein in human body. Though collagen I (COLI) and collagen III (COLIII) are the predominant collagen types in connective tissues and they form stable hybrid fibrils at varied ratios, cell responses to the hybrid matrices are underinvestigated. In this work, we aim to explicate the distinctive roles of COLI and COLIII in fibroblast activation. Unidirectionally aligned COLI, COLIII and COLI-COLIII hybrid nanofibrils were generated via epitaxial growth of collagen on mica. AFM analyses revealed that, with the increase of COLI/COLIII ratio, the fibril width and stiffness increased and the binding affinity of cells to the matrix decreased. A hybrid matrix was found to activate fibroblasts the most effectively, characterized by extensive cell polarization with rigid stress fiber bundles and high α-SMA expression, and by the highest-level of collagen synthesis. It is ascribed to the fine balance between biochemical and biophysical cues achieved on the hybrid matrix. Thus, matrices of aligned COLI-COLIII hybrid fibrils and their derived multifunctional composites can be good candidates of implantation scaffolds for tissue regeneration.

Lumenato protects normal human dermal fibroblasts from neutrophil-induced collagen-3 damage in co-cultures

Collagen is the major structural protein in the extracellular matrix of skin produced by fibroblasts. UV exposure results in infiltration of neutrophils within the epidermis and dermis, inducing collagen damage and contributing to the process of photo-aging. Collagen-3 is an integral structural component with collagen-1, and is an important regulator of collagen-1 fibrillogenesis. Addition of neutrophils activated with TNFα to normal human dermal fibroblast cultures, but not their supernatant, caused significant collagen-3 damage. To study whether Lumenato can protect from collagen-3 damage, it was added to co-cultures of Normal human dermal fibroblasts and neutrophils activated with TNFα. Lumenato prevented collagen-3 damage induced by activated neutrophils in a dose-dependent manner in the co-cultures. Lumenato also induced a low rate of collagen-3 synthesis in a dose-dependent manner detected by pro-collagen-3 secretion, but did not affect fibroblast cell number. Although Lumenato inhibited MMP-8, MMP-9, and elastase secreted from neutrophils, its main effect was in inhibiting both NADPH oxidase-producing superoxides and MPO activity-producing halides in a dose-dependent manner that correlated with protection from collagen-3 damage. In conclusion, the results suggest that Lumenato induces low levels of collagen-3 that may contribute for skin health and is very effective in defending the co-cultures from collagen-3 damage by inhibiting free radicals secreted from neutrophils, thus, indicating Lumenato's possible potential for skin protection.

Fibrotic Strictures in Crohn's Disease: Mechanisms and Predictive Factors

Fibrotic strictures are one of the most severe complications of Crohn's Disease (CD). They occur in about 50% of patients at five years and in 70% at ten years of the diagnosis. The only treatment available for symptomatic fibrotic strictures is surgical resection and endoscopic dilation. Both strategies are associated with a high rate of recurrence, and with multiple surgical resections, which pose the threat of surgical morbidity and short bowel syndrome. Therefore, it is crucial to identify, early, the patients more prone to develop intestinal fibrosis to intensify follow-ups, switch to more aggressive treatments, and suggest lifestyle modifications. Scarce data are available concerning biomarkers and genetic determinants to predict which patient will develop intestinal fibrosis. Biologic or clinical markers would be useful to determine this subgroup of CD patients and to predict the onset of intestinal fibrosis and, ideally, its severity. Furthermore, the identification of environmental risk factors may suggest lifestyle changes aimed at modifying the natural course, thus decreasing the risk of complicated CD. In this review, we will critically revise clinical, environmental, genetic, and serologic factors that have been associated with a complicated CD course with a particular focus on the fibrostenosing phenotype and their possible implications as predictive factors of intestinal fibrosis.

Role of TGF-Beta and Smad7 in Gut Inflammation, Fibrosis and Cancer

The human gastrointestinal tract contains the largest population of immune cells in the body and this is a reflection of the fact that it is continuously exposed to a myriad of dietary and bacterial antigens. Although these cells produce a variety of inflammatory cytokines that could potentially promote tissue damage, in normal conditions the mucosal immune response is tightly controlled by counter-regulatory factors, which help induce and maintain gut homeostasis and tolerance. One such factor is transforming growth factor (TGF)-β1, a cytokine produced by multiple lineages of leukocytes, stromal cells and epithelial cells, and virtually targets all the gut mucosal cell types. Indeed, studies in animals and humans have shown that defects in TGF-β1 production and/or signaling can lead to the development of immune-inflammatory pathologies, fibrosis and cancer in the gut. Here, we review and discuss the available evidence about the role of TGF-β1 and Smad7, an inhibitor of TGF-β1 activity, in gut inflammation, fibrosis and cancer with particular regard to the contribution of these two molecules in the pathogenesis of inflammatory bowel diseases and colon cancer.

Mechanism of fibrosis and stricture formation in Crohn's disease

Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract that leads to substantial suffering for millions of patients. In some patients, the chronic inflammation leads to remodelling of the extracellular matrix and fibrosis. Fibrosis, in combination with expansion of smooth muscle layers, leaves the bowel segment narrowed and stiff resulting in strictures, which often require urgent medical intervention. Although stricture development is associated with inflammation in the affected segment, anti‐inflammatory therapies fall far short of treating strictures. At best, current therapies might allow some patients to avoid surgery in a shorter perspective and no anti‐fibrotic therapy is yet available. This likely relates to our poor understanding of the mechanism underlying stricture development. Chronic inflammation is a prerequisite, but progression to strictures involves changes in fibroblasts, myofibroblasts and smooth muscle cells in a poorly understood interplay with immune cells and environmental cues. Much of the experimental evidence available is from animal models, cell lines or non‐strictured patient tissue. Accordingly, these limitations create the basis for many previously published reviews covering the topic. Although this information has contributed to the understanding of fibrotic mechanisms in general, in the end, data must be validated in strictured tissue from patients. As stricture formation is a serious complication of CD, we endeavoured to summarize findings exclusively performed using strictured tissue from patients. Here, we give an update of the mechanism driving this serious complication in patients, and how the strictured tissue differs from adjacent unaffected tissue and controls.

Synthesis and Formulation of Four-Arm PolyDMAEA-siRNA Polyplex for Transient Downregulation of Collagen Type III Gene Expression in TGF-β1 Stimulated Tenocyte Culture

The natural healing process for tendon repair is associated with high upregulation of collagen type III, leading to scar tissue and tendon adhesions with functionally deficient tendons. Gene delivery systems are widely reported as potential nanotherapeutics to treat diseases, providing a promising approach to modulate collagen type III synthesis. This work investigates a proof-of-concept four-arm cationic polymer-siRNA polyplex to mediate a transient downregulation of collagen type III expression in a tendon cell culture system. The tendon culture system was first supplemented with TGF-β1 to stimulate the upregulation of collagen type III prior to silencing experiments. The four-arm poly[2-(dimethylamino) ethyl acrylate] (PDMAEA) polymer was successfully synthesized via RAFT polymerization and then mixed with siRNA to formulate the PDMAEA-siRNA polyplexes. The formation of the polyplex was optimized for the N:P ratio (10:1) and confirmed by agarose gel electrophoresis. The size and solution behavior of the polyplex were analyzed by dynamic light scattering and zeta potential, showing a hydrodynamic diameter of 155 ± 21 nm and overall positive charge of +30 mV at physiological pH. All the polyplex concentrations used had a minimal effect on the metabolic activity of cultured cells, indicating good biocompatibility. The dose and time effects of the TGF-β1 on collagen type III gene expressions were analyzed by qPCR, showing an optimal dose of 10 ng mL^-1 TGF-β1 and 3-fold increase of COL3α1 expression at 48 h in cultured tenocytes. The PDMAEA-siRNA polyplex concept observed a limited yet successful and promising efficiency in silencing collagen type III at 48 h compared to PEI-siRNA. Therefore, this concept is a promising approach to reduce tissue scarring and adhesion following injuries.

Exploring organ-specific features of fibrogenesis using murine precision-cut tissue slices

Fibrosis is the hallmark of pathologic tissue remodelling in most chronic diseases. Despite advances in our understanding of the mechanisms of fibrosis, it remains uncured. Fibrogenic processes share conserved core cellular and molecular pathways across organs. In this study, we aimed to elucidate shared and organ-specific features of fibrosis using murine precision-cut tissue slices (PCTS) prepared from small intestine, liver and kidneys. PCTS displayed substantial differences in their baseline gene expression profiles: 70% of the extracellular matrix (ECM)-related genes were differentially expressed across the organs. Culture for 48 h induced significant changes in ECM regulation and triggered the onset of fibrogenesis in all PCTS in organ-specific manner. TGFβ signalling was activated during 48 h culture in all PCTS. However, the degree of its involvement varied: both canonical and non-canonical TGFβ pathways were activated in liver and kidney slices, while only canonical, Smad-dependent, cascade was involved in intestinal slices. The treatment with galunisertib blocked the TGFβRI/SMAD2 signalling in all PCTS, but attenuated culture-induced dysregulation of ECM homeostasis and mitigated the onset of fibrogenesis with organ-specificity. In conclusion, regardless the many common features in pathophysiology of organ fibrosis, PCTS displayed diversity in culture-induced responses and in response to the treatment with TGFβRI kinase inhibitor galunisertib, even though it targets a core fibrosis pathway. A clear understanding of the common and organ-specific features of fibrosis is the basis for developing novel antifibrotic therapies.

Inflammatory Bowel Disease Types Differ in Markers of Inflammation, Gut Barrier and in Specific Anti-Bacterial Response

Crohn’s disease (CD), ulcerative colitis (UC) and inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC-IBD), share three major pathogenetic mechanisms of inflammatory bowel disease (IBD)-gut dysbiosis, gut barrier failure and immune system dysregulation. While clinical differences among them are well known, the underlying mechanisms are less explored. To gain an insight into the IBD pathogenesis and to find a specific biomarker pattern for each of them, we used protein array, ELISA and flow cytometry to analyze serum biomarkers and specific anti-microbial B and T cell responses to the gut commensals. We found that decrease in matrix metalloproteinase (MMP)-9 and increase in MMP-14 are the strongest factors discriminating IBD patients from healthy subjects and that PSC-IBD patients have higher levels of Mannan-binding lectin, tissue inhibitor of metalloproteinases 1 (TIMP-1), CD14 and osteoprotegerin than patients with UC. Moreover, we found that low transforming growth factor-β1 (TGF-β1) is associated with disease relapse and low osteoprotegerin with anti-tumor necrosis factor-alpha (TNF-α) therapy. Patients with CD have significantly decreased antibody and increased T cell response mainly to genera Eubacterium, Faecalibacterium and Bacteroides. These results stress the importance of the gut barrier function and immune response to commensal bacteria and point at the specific differences in pathogenesis of PSC-IBD, UC and CD.

Type III collagen (COL3A1): Gene and protein structure, tissue distribution, and associated diseases

Collagen alpha-1(III) chain, also known as the alpha 1 chain of type III collagen, is a protein that in humans is encoded by the COL3A1 gene. Three alpha 1 chains are required to form the type III collagen molecule which has a long triple-helical domain. Type III collagen, an extracellular matrix protein, is synthesized by cells as a pre-procollagen. It is found as a major structural component in hollow organs such as large blood vessels, uterus and bowel. Other functions of type III collagen include interaction with platelets in the blood clotting cascade and it is also an important signaling molecule in wound healing. Mutations in the COL3A1 gene cause the vascular type of Ehlers-Danlos syndrome (vEDS; OMIM 130050). It is the most serious form of EDS, since patients often die suddenly due to a rupture of large arteries. Inactivation of the murine Col3a1 gene leads to a shorter life span in homozygous mutant mice. The mice die prematurely from a rupture of major arteries mimicking the human vEDS phenotype. The biochemical and cellular effects of COL3A1 mutations have been studied extensively. Most of the glycine mutations lead to the synthesis of type III collagen with reduced thermal stability, which is more susceptible for proteinases. Intracellular accumulation of this normally secreted protein is also found. Ultrastructural analyses have demonstrated dilated rough endoplasmic reticulum and changes in the diameter of collagen fibers. Other clinical conditions associated with type III collagen are several types of fibroses in which increased amounts of type III collagen accumulate in the target organs.

Smad7 and Colorectal Carcinogenesis: A Double-Edged Sword

Colorectal carcinogenesis is a complex process in which many immune and non-immune cells and a huge number of mediators are involved. Among these latter factors, Smad7, an inhibitor of the transforming growth factor (TGF)-β1 signaling that has been involved in the amplification of the inflammatory process sustaining chronic intestinal inflammation, is supposed to make a valid contribution to the growth and survival of colorectal cancer (CRC) cells. Smad7 is over-expressed by tumoral cells in both sporadic CRC and colitis-associated CRC, where it sustains neoplastic processes through activation of either TGFβ-dependent or non-dependent pathways. Consistently, genome-wide association studies have identified single nucleotide polymorphisms of the Smad7 gene associated with CRC and shown that either amplification or deletion of the Smad7 gene associates with a poor prognosis or better outcome, respectively. On the other hand, there is evidence that over-expression of Smad7 in immune cells infiltrating the inflamed gut of patients with inflammatory bowel disease can elicit anti-tumor responses, with the down-stream effect of attenuating CRC cell growth. Taken together, these observations suggest a double role of Smad7 in colorectal carcinogenesis, which probably depends on the cell subset and the biological context analyzed. In this review, we summarize the available evidences about the role of Smad7 in both sporadic and colitis-associated CRC.

Toxoplasma gondii causes increased ICAM-1 and serotonin expression in the jejunum of rats 12 h after infection

OBJECTIVE

To analyze the remodeling dynamics of total collagen, type I and III, the expression of ICAM-1 and 5-HT in the jejunum of rats.

METHODS

Twenty-eight Wistar rats were randomly assigned to two experimental groups: the control group (CG, n = 7) and the infected group (receiving 5,000 sporulated T. gondii oocysts - ME49 strain, genotype II, n = 21). Seven infected rats each at 6 (G6), 12 (G12), and 24 (G24) hours post infection were sacrificed and segments of jejunum were collected for standard histological, histochemical, and immunohistochemistry processing techniques.

RESULTS

The infection promoted ICAM-1 and 5-HT expression, type III collagen, and total mast cell increases. However, it also caused a reduction in the area occupied by type I collagen fibers, and in submucosa thickness, and caused ganglion and peri-ganglion alterations.

CONCLUSION

The structural damage caused by toxoplasmic infection is intense during the first 24 h post inoculation. At peak dissemination, from 12 to 24 h, there is an increase in ICAM-1 and 5-HT expression, with intense migration of mast cells to the site of infection. There was also a reduction in submucosa thickness, and an effective loss of extracellular matrix (ECM) organization, which included changes in the dynamics of type I and III total collagen deposition.

Transforming Growth Factor-β1/Smad7 in Intestinal Immunity, Inflammation, and Cancer

In physiological conditions, the activity of the intestinal immune system is tightly regulated to prevent tissue-damaging reactions directed against components of the luminal flora. Various factors contribute to maintain immune homeostasis and diminished production and/or function of such molecules trigger and/or propagate detrimental signals, which can eventually lead to chronic colitis and colon cancer. One such a molecule is transforming growth factor-β1 (TGF-β1), a cytokine produced by many inflammatory and non-inflammatory cells and targeting virtually all the intestinal mucosal cell types, with the down-stream effect of activating intracellular Smad2/3 proteins and suppressing immune reactions. In patients with inflammatory bowel diseases (IBD), there is defective TGF-β1/Smad signaling due to high Smad7, an inhibitor of TGF-β1 activity. Indeed, knockdown of Smad7 with a specific antisense oligonucleotide restores endogenous TGF-β1 activity, thereby inhibiting inflammatory pathways in patients with IBD and colitic mice. Consistently, mice over-expressing Smad7 in T cells develop severe intestinal inflammation in various experimental models. Smad7 expression is also upregulated in colon cancer cells, in which such a protein controls positively intracellular pathways that sustain neoplastic cell growth and survival. We here review the role of TGF-β1 and Smad7 in intestinal immunity, inflammation, and cancer.

Structural and functional failure of fibrillin‑1 in human diseases (Review)

Fibrillins (FBNs) are key relay molecules that form the backbone of microfibrils in elastic and non‑elastic tissues. Interacting with other components of the extracellular matrix (ECM), these ubiquitous glycoproteins exert pivotal roles in tissue development, homeostasis and repair. In addition to mechanical support, FBN networks also exhibit regulatory activities on growth factor signalling, ECM formation, cell behaviour and the immune response. Consequently, mutations affecting the structure, assembly and stability of FBN microfibrils have been associated with impaired biomechanical tissue properties, altered cell‑matrix interactions, uncontrolled growth factor or cytokine activation, and the development of fibrillinopathies and associated severe complications in multiple organs. Beyond a panoramic overview of structural cues of the FBN network, the present review will also describe the pathological implications of FBN disorders in the development of inflammatory and fibrotic conditions.

TGF-β in inflammatory bowel disease: a key regulator of immune cells, epithelium, and the intestinal microbiota

Inflammatory bowel disease (IBD) is defined as chronic intestinal inflammation, and includes ulcerative colitis and Crohn's disease. Multiple factors are involved in the pathogenesis of IBD, and the condition is characterized by aberrant mucosal immune reactions to intestinal microbes in genetically susceptible hosts. Transforming growth factor-β (TGF-β) is an immune-suppressive cytokine produced by many cell types and activated by integrins. Active TGF-β binds to its receptor and regulates mucosal immune reactions through the TGF-β signaling pathway. Dysregulated TGF-β signaling is observed in the intestines of IBD patients. TGF-β signal impairment in specific cell types, such as T-cells and dendritic cells, results in spontaneous colitis in mouse models. In addition, specific intestinal microbes contribute to immune homeostasis by modulating TGF-β production. In this review, we describe the role of TGF-β in intestinal immunity, focusing on immune cells, epithelium, and intestinal microbes. In addition, we present potential therapeutic strategies for IBD that target TGF-β.

The extracellular matrix in IBD: a dynamic mediator of inflammation

PURPOSE OF REVIEW

The extracellular matrix (ECM) is a frequently overlooked component of the pathogenesis of inflammatory bowel disease (IBD). However, the functional and clinically significant interactions between immune as well as nonimmune cells with the ECM have important implications for disease pathogenesis. In this review, we discuss how the ECM participates in process associated with IBD that involves diverse cell types of the intestine.

RECENT FINDINGS

Remodeling of the ECM is a consistent feature of IBD, and studies have implicated key ECM molecules in IBD pathogenesis. While the majority of prior studies have focused on ECM degradation by proteases, more recent studies have uncovered additional degrading enzymes, identified fragments of ECM components as potential biomarkers, and revealed that ECM synthesis is increased in IBD. These new studies support the notion that the ECM, rather than acting as a passive element, is an active participant in promoting inflammation.

SUMMARY

New studies have offered exciting clues about the function of the ECM during IBD pathogenesis. The balance of ECM synthesis and turnover is altered in IBD, and the molecules involved exhibit discreet biological functions that regulate inflammation on the basis of specific cell type and matrix molecule.

Protective effect of Averrhoa bilimbi L. fruit extract on ulcerative colitis in wistar rats via regulation of inflammatory mediators and cytokines

Ulcerative Colitis (UC) is a lingering type of Inflammatory Bowel Disease (IBD) which affects the colon mucosa. Ulcerative colitis is majorly associated with oxidative stress and inflammation in colon tissue leading to damage. Averrhoa bilimbi L. fruit is rich in antioxidant phytochemicals including Vitamin C. In the current research, we have evaluated the defence mechanism of Averrhoa bilimbi L. on Ulcerative Colitis (UC). Male wistar rats were treated with Averrhoa bilimbi L. fruit extract (50mg/kg/bwt and 100mg/kg/bwt) and a standard drug Sulfasalazine (100mg/kg/bwt) for 6 consecutive days via intra peritoneally. After one day fasting, rats were given single dose of 3% 2ml of acetic acid through anal (intra-anal) region to induce Ulcerative Colitis. The protective and therapeutic effect of fruit extract on UC was assessed by comparing the relevant changes observed in the normal and treated group. In treated group the level of mucosal injury was decreased (ulcer score - 2) when compared to the control group (ulcer score - 9). The abnormal increase observed in the inflammation mediator cytokines in control rats, i.e IL-1β, IL-6, TNF-α levels were decreased significantly (**p<0.01) in the Averrhoa bilimbi L. fruit extract treated groups. The increase in weights of the colon tissue and spleen of the control rats were found to be reduced in treated groups. The levels of inflammatory markers iNOS and COX-2 were also decreased in treated group significantly (**p<0.01) when compared with the control. Furthermore, the treatment with Averrhoa bilimbi L. fruit extract has shown a significant antioxidant activity in the UC condition by reducing the levels of NO and enhancing the levels of SOD and GSH in the colon tissue. These results demonstrate the effective anti-ulcerative colitis activity of the Averrhoa bilimbi L. fruit extract in experimental wistar rats.

Mechanisms, Management, and Treatment of Fibrosis in Patients With Inflammatory Bowel Diseases

In the last 10 years, we have learned much about the pathogenesis, diagnosis, and management of intestinal fibrosis in patients with inflammatory bowel diseases. Just a decade ago, intestinal strictures were considered to be an inevitable consequence of long-term inflammation in patients who did not respond to anti-inflammatory therapies. Inflammatory bowel diseases-associated fibrosis was seen as an irreversible process that frequently led to intestinal obstructions requiring surgical intervention. This paradigm has changed rapidly, due to the antifibrotic approaches that may become available. We review the mechanisms and diagnosis of this serious complication of inflammatory bowel diseases, as well as factors that predict its progression and management strategies.

Smooth Muscle Hyperplasia/Hypertrophy is the Most Prominent Histological Change in Crohn's Fibrostenosing Bowel Strictures: A Semiquantitative Analysis by Using a Novel Histological Grading Scheme

BACKGROUND

The simplistically and ambiguously termed 'fibrostenosis' of bowel is a hallmark of severe Crohn's disease [CD] and a major contributor to medical treatment failure. Non-invasive imaging assessment and novel medical therapy targeting this condition are under investigation, which particularly requires a better understanding of the underlying histological basis.

METHODS

We analysed 48 patients with stricturing Crohn's ileitis or/and colitis that required surgical resection. The most representative sections of the fibrostenotic, non-stenotic and uninvolved regions were reviewed for histological analysis. For each layer of bowel wall (mucosa including muscularis mucosae [MU], submucosa [SM], muscularis propria [MP], subserosal adventitia [SS]), histological abnormalities were evaluated individually, including active and chronic inflammation, fibrosis, smooth muscle hyperplasia or hypertrophy, neuronal hypertrophy and adipocyte proliferation. A novel semiquantitative histological grading scheme was created.

RESULTS

The most significant histopathological features characterizing the stricturing intestines were smooth muscle hyperplasia of SM, hypertrophy of MP and chronic inflammation. The muscular alteration was predominant in all layers. The overall muscular hyperplasia/hypertrophy was positively correlated with chronic inflammation and negatively correlated with fibrosis, whereas SM muscular hyperplasia was also associated with MU active inflammation. Similar changes, to a lesser extent, occurred in the adjacent non-stenotic inflamed bowel as well.

CONCLUSIONS

In CD-associated 'fibrostenosis', it is the smooth muscle hyperplasia/hypertrophy that contributes most to the stricturing phenotype, whereas fibrosis is less significant. The 'inflammation-smooth muscle hyperplasia axis' may be the most important in the pathogenesis of Crohn's strictures.

Anti-TNFα alters the natural history of experimental Crohn's disease in rats when begun early, but not late, in disease

Anti-TNFα therapy decreases inflammation in Crohn's disease (CD). However, its ability to decrease fibrosis and alter the natural history of CD is not established. Anti-TNF-α prevents inflammation and fibrosis in the peptidoglycan-polysaccharide (PG-PS) model of CD. Here we studied anti-TNF-α in a treatment paradigm. PG-PS or human serum albumin (HSA; control) was injected into bowel wall of anesthetized Lewis rats at laparotomy. Mouse anti-mouse TNF-α or vehicle treatment was begun day (d)1, d7, or d14 postlaparotomy. Rats were euthanized d21-23. Gross abdominal and histologic findings were scored. Cecal levels of relevant mRNAs were measured by quantitative real-time PCR. There was a stepwise loss of responsiveness when anti-TNFα was begun on d7 and d14 compared with d1 that was seen in the percent decrease in the median gross abdominal score and histologic inflammation score in PG-PS-injected rats [as %decrease; gross abdominal score: d1 = 75% (P = 0.003), d7 = 57% (P = 0.18), d14 = no change (P = 0.99); histologic inflammation: d1 = 57% (P = 0.006), d7 = 50% (P = 0.019), d14 = no change (P = 0.99)]. This was also reflected in changes in IL-1β, IL-6, TNF-α, IGF-I, TGF-β1, procollagen I, and procollagen III mRNAs that were decreased or trended downward in PG-PS-injected animals given anti-TNF-α beginning d1 or d7 compared with vehicle-treated rats; there was no effect if anti-TNF-α was begun d14. This change in responsiveness to anti-TNFα therapy was coincident with a major shift in the cytokine milieu observed on d14 in the PG-PS injected rats (vehicle treated). Our data are consistent with the clinical observation that improved outcomes occur when anti-TNF-α therapy is initiated early in the course of CD.

Prevalence of Colonic Diverticulosis in Patients Affected by Ulcerative Colitis: A Prospective Study

BACKGROUND

Diverticulosis of the colon is an acquired condition that results from herniation of the mucosa and submucosa through defects in the muscular layer. The true prevalence of colonic diverticulosis is difficult to measure because most individuals are asymptomatic. In particularly, in literature, there are few studies about the prevalence of colonic diverticulosis in patients affected by ulcerative colitis (UC).

GOALS

To investigate the prevalence of colonic diverticulosis in UC and in adult patients referred in a single center.

STUDY

Consecutive patients, referred to our institution to undergo a colonoscopy for colorectal cancer screening and/or for UC assessment, between January 1, 2014 and December 31, 2014, were studied.

RESULTS

Six hundred five consecutive patients were studied: 438 (72.4%) due to colorectal cancer screening (group A) and 167 (27.6%) for UC assessment (group B). Prevalence of colonic diverticulosis was higher in group A than group B (27.8% vs. 10.8%, P<0.0001). Female gender in patients with colonic diverticulosis was higher in group A than group B (55.7% vs. 22.2%, P=0.0106). Sigma and left colon was mainly involved in group A than group B (97.6% vs. 66.7%, P=0.0001), whereas in group B the right colon was mainly involved in group B versus group A (22.2% vs. 0.8%, P=0.0009).

CONCLUSIONS

Prevalence of colonic diverticulosis was significantly lower in patients with UC than in control group. UC may, therefore, be a protective factor for colonic diverticulosis occurrence.

European Crohn's and Colitis Organisation Topical Review on Prediction, Diagnosis and Management of Fibrostenosing Crohn's Disease

This ECCO topical review of the European Crohn's and Colitis Organisation [ECCO] focused on prediction, diagnosis, and management of fibrostenosing Crohn's disease [CD]. The objective was to achieve evidence-supported, expert consensus that provides guidance for clinical practice.

RAGE and TGF-β1 Cross-Talk Regulate Extracellular Matrix Turnover and Cytokine Synthesis in AGEs Exposed Fibroblast Cells

AGEs accumulation in the skin affects extracellular matrix (ECM) turnover and triggers diabetes associated skin conditions and accelerated skin aging. The receptor of AGEs (RAGE) has an essential contribution to cellular dysfunction driven by chronic inflammatory responses while TGF-β1 is critical in both dermal homeostasis and inflammation. We investigated the contribution of RAGE and TGF-β1 to the modulation of inflammatory response and ECM turnover in AGEs milieu, using a normal fibroblast cell line. RAGE, TGF-β1, collagen I and III gene and protein expression were upregulated after exposure to AGEs-BSA, and MMP-2 was activated. AGEs-RAGE was pivotal in NF-κB dependent collagen I expression and joined with TGF-β1 to stimulate collagen III expression, probably via ERK1/2 signaling. AGEs-RAGE axis induced upregulation of TGF-β1, TNF-α and IL-8 cytokines. TNF-α and IL-8 were subjected to TGF-β1 negative regulation. RAGE’s proinflammatory signaling also antagonized AGEs-TGF-β1 induced fibroblast contraction, suggesting the existence of an inhibitory cross-talk mechanism between TGF-β1 and RAGE signaling. RAGE and TGF-β1 stimulated anti-inflammatory cytokines IL-2 and IL-4 expression. GM-CSF and IL-6 expression appeared to be dependent only on TGF-β1 signaling. Our data also indicated that IFN-γ upregulated in AGEs-BSA milieu in a RAGE and TGF-β1 independent mechanism. Our findings raise the possibility that RAGE and TGF-β1 are both involved in fibrosis development in a complex cross-talk mechanism, while also acting on their own individual targets. This study contributes to the understanding of impaired wound healing associated with diabetes complications.

Pathogenic aspects and therapeutic avenues of intestinal fibrosis in Crohn's disease

In Crohn's disease, one of the two major forms of inflammatory bowel diseases in human beings, persistent and chronic inflammation promotes fibrotic processes thereby facilitating formation of strictures, the most common indication for surgical intervention in this disorder. The pathogenesis of Crohn's disease-associated fibrosis is not fully understood, but variants of genes involved in the recognition of microbial components/products [e.g. CARD15 (caspase-activating recruitment domain 15) and ATG16L1 (autophagy-related 16-like 1)] are associated with this phenotype, and experimental evidence suggests that intestinal fibrosis results from an altered balance between deposition of ECM (extracellular matrix) and degradation of ECM by proteases. Studies have also contributed to identify the main phenotypic and functional alterations of cells involved in the fibrogenic process, as well as molecules that stimulate such cells to produce elevated amounts of collagen and other ECM-related proteins. In the present review, we assess the current knowledge about cellular and molecular mediators of intestinal fibrosis and describe results of recent studies aimed at testing the preventive/therapeutic effect of compounds in experimental models of intestinal fibrosis.

US-based Real-time Elastography for the Detection of Fibrotic Gut Tissue in Patients with Stricturing Crohn Disease

PURPOSE

To assess whether ultrasonography (US)-based real-time elastography (RTE) can be used to detect gut fibrosis.

MATERIALS AND METHODS

In this institutional review board-approved, prospective, proof-of-concept study, unaffected and affected gut segments in 10 patients with Crohn disease (four women, six men; median age, 49 years) were examined pre-, intra-, and postoperatively with US, including RTE to assess strain. Disease activity was scored by using the Limberg index on the basis of (a) bowel wall thickness and (b) size and extent of Doppler signal. After surgical resection, strain of full gut wall segments was measured with direct tensiometry. Gut wall layers, fibrosis, and collagen content were quantified histologically. Aggregated data per patient, disease status, and available measurements were assessed with mixed-effects models.

RESULTS

Unaffected versus affected gut segments yielded higher RTE (mean ± standard deviation, 169.0 ± 27.9 vs 43.0 ± 25.9, respectively) and tensiometry (mean, 77.1 ± 21.4 vs 13.3 ± 11.2, respectively) values used to assess strain (both P < .001). There was good correlation between pre-, intra-, and postoperative RTE values of unaffected (intraclass correlation coefficient, 0.572) and affected (intraclass correlation coefficient, 0.830) segments. RTE was not associated with pre- or intraoperative Limberg scores (median, 1 vs 2; P = .255 and .382, respectively). Affected internal (median, 2011 vs 1363 μm; P = .011) and external (median, 929 vs 632 μm; P = .013) muscularis propria, serosa (median, 245 vs 64 μm; P = .019), and muscularis mucosae (median, 451 vs 80 μm; P = .031) were wider than unaffected segments. Width differences of internal muscularis propria and mucularis mucosae were associated with RTE-assessed strain (P = .044 and .012, respectively) and tensiometry-assessed strain (P = .006 and .014, respectively). Masson trichrome (median, 4 vs 0; P < .001) and elastica-van Gieson (median, 805 346 μm(2) vs 410 649 μm(2); P < .001) stains and western blotting (median, 2.01 vs 0.87; P = .009) demonstrated a higher collagen content in affected versus unaffected segments and were associated with RTE-assessed strain (both P < .001) and tensiometry-assessed strain (P < .001 and 0.025, respectively).

CONCLUSION

RTE can be used to detect fibrosis in human Crohn disease. Online supplemental material is available for this article.

Protective effect of Xuebijing injection on paraquat-induced pulmonary injury via down-regulating the expression of p38 MAPK in rats

Background

Exposure to paraquat results in acute lung injury. A systemic inflammatory response has been widely established as a contributor to paraquat-induced acute lung injury. Recent studies have reported that consumption of Xuebijing prevents inflammatory response-induced diseases. This study investigated whether consumption of Xuebijing protected rats against paraquat-induced acute lung injury.

Methods

Adult male Sprague Dawley rats were randomly divided into four groups: control group; paraquat group; paraquat + Xuebijing group; and paraquat + dexamethasone group. Rats in the paraquat, paraquat + Xuebijing and paraquat + dexamethasone groups were intraperitoneally injected with paraquat (30 mg/kg) or administered paraquat and Xuebijing at 8 mL/kg or dexamethasone at 5 mg/kg, respectively, via an injection into the tail vein. Lung p38 MAPK, NF-κB65, IkB, p-IκB-α, HIF-1α, Nrf2 and TGF-β1 expression were essayed using western blotting. IL-6, TNF-α, IL-1β, IL-10, TGF-β1 and PIIIP were measured using ELISA. ROS, oxidised glutathione and glutathione activity were measured.

Results

After inducing acute lung injury with paraquat for 24 h, Xuebijing was observed to block lung p-p38 MAPK, NF-κB65, HIF-1α, p-IκB-α and TGF-β1 expression, and increased Nrf2 and IkB expression. The numbers of neutrophils and lymphocytes and total number of cells were significantly lower in the Xuebijing group compared with the control group. IL-6, TNF-α, IL-1β, TGF-β1 and PIIIP levels were significantly decreased in the Xuebijing group. ROS and oxidised glutathione activity were markedly inhibited by Xuebijing. Histological evaluation showed attenuation of the effects of Xuebijing on paraquat-induced lung injury. Compared with the paraquat + dexamethasone group, the Xuebijing + paraquat group showed no significant differences.

Conclusions

Inhibiting the expression of p38 MAPK and NF-κB65 was crucial for the protective effects of Xuebijing on paraquat-induced acute lung injury. The findings suggest that Xuebijing could effectively ameliorate paraquat-induced acute lung injury in rats. Xuebijing was as effective as dexamethasone at improving paraquat-induced lung injury by regulating lung inflammation, lung function and oxidative stress responses.

The multifaceted mast cell in inflammatory bowel disease

Mast cells (MCs) are tissue-resident immune cells that carry out protective roles against pathogens. In disease states, such as inflammatory bowel disease, these granulocytes release a diverse array of mediators that contribute to inflammatory processes. They also participate in wound repair and tissue remodeling. In this review, the composition of MCs and how their phenotypes can be altered during inflammation of the gastrointestinal tract is detailed. Animal and human clinical studies that have implicated the participation of MCs in inflammatory bowel disease are reviewed, including the contribution of the cell's mediators to clinical symptoms, stress-triggered inflammation, and fistula and strictures. Studies that have focused on negating the proinflammatory roles of MCs and their mediators in animal models suggest new targets for therapies for patients with inflammatory bowel disease.

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.

Persistent infection with Crohn's disease-associated adherent-invasive Escherichia coli leads to chronic inflammation and intestinal fibrosis

Crohn’s disease is a chronic inflammatory condition of the gastrointestinal tract in which alterations to the bacterial community contribute to disease. Adherent-invasive E. coli (AIEC) are associated with human Crohn’s disease, however their role in intestinal immunopathology is unclear due to the lack of an animal model compatible with chronic timescales. Here we establish chronic AIEC infection in streptomycin-treated conventional mice (CD-1, DBA/2, C3HeN, 129e, C57BL/6), enabling the study of host response and immunopathology. AIEC induces an active Th17 response, heightened levels of proinflammatory cytokines and fibrotic growth factors, with transmural inflammation and fibrosis. Depletion of CD8+ T cells increases cecal bacterial load, pathology and intestinal fibrosis in C57BL/6 mice suggesting a protective role. Our findings provide evidence that chronic AIEC infections result in immunopathology similar to that seen in Crohn’s disease. With this model, research into the host and bacterial genetics associated with AIEC-induced disease becomes more widely accessible.

The role of transforming growth factor (TGF)-β in modulating the immune response and fibrogenesis in the gut

Transforming growth factor (TGF)-β, a pleiotropic cytokine released by both immune and non-immune cells in the gut, exerts an important tolerogenic action by promoting regulatory T cell differentiation. TGF-β also enhances enterocyte migration and regulates extracellular matrix turnover, thereby playing a crucial role in tissue remodeling in the gut. In this review we describe the mechanisms by which abnormal TGF-β signaling impairs intestinal immune tolerance and tissue repair, thus predisposing to the onset of immune-mediated bowel disorders, such as inflammatory bowel disease and celiac disease. Additionally, we will discuss potential therapeutic strategies aiming at restoring physiologic TGF-β signaling in chronic intestinal diseases.

Proinflammatory cytokines induce crosstalk between colonic epithelial cells and subepithelial myofibroblasts: implication in intestinal fibrosis

BACKGROUND AND AIMS

Colonic epithelial cells and adjacent subepithelial myofibroblasts are important counterparts in the pathogenesis of intestinal inflammation and fibrosis. We investigated the possible crosstalk between them, whilst focusing on the mucosal inflammation pathways that potentially trigger intestinal fibrosis.

METHODS

We studied the effects of proinflammatory cytokines (IL-1α, TNF-α, IFN-γ) on human colonic epithelial cell lines and the effects of epithelial cell-conditioned media on primary human colonic subepithelial myofibroblasts isolated from normal controls or patients with inflammatory Crohn's disease along with the corresponding 18CO cell line. Readouts included production of TGF-β and TIMP-1, total collagen synthesis, matrix metalloproteinases MMP-2 and MMP-9 and myofibroblast migration/mobility.

RESULTS

Proinflammatory cytokines upregulated TGF-β and TIMP-1 in colonic epithelial cells. Conditioned medium from these epithelial cell cultures induced production of MMP-9 and collagen and inhibited the migration/mobility of subepithelial myofibroblasts. MMP-9 production depended on endothelin receptor A signalling on responding myofibroblasts. Collagen up-regulation was independent of TGF-β, CTGF, TF and endothelin. Subepithelial myofibroblasts isolated from Crohn's disease patients had similar responses to those isolated from normal controls, with the exception of higher basal collagen production.

CONCLUSIONS

Our study indicates that colonic epithelial cells may respond to an inflammatory milieu by inducing myofibroblast functions similar to those observed during intestinal fibrosis.

Losartan reduces trinitrobenzene sulphonic acid-induced colorectal fibrosis in rats

BACKGROUND

Intestinal fibrosis is a challenging clinical condition in several fibrostenosing enteropathies, particularly Crohn's disease. Currently, no effective preventive measures or medical therapies are available for intestinal fibrosis. Fibrosis, due to an abnormal accumulation of extracellular matrix proteins, is a chronic and progressive process mediated by cell⁄matrix⁄cytokine and growth factor interactions, but may be a reversible phenomenon. Of the several molecules regulating fibrogenesis, transforming growth factor-beta 1 (TGF-b1) appears to play a pivotal role; it is strongly induced by the local activation of angiotensin II. The levels of both TGF-b1 and angiotensin II are elevated in fibrostenosing Crohn's disease.

AIMS

To evaluate the in vivo effect of losartan - an angiotensin II receptor antagonist - on the course of chronic colitis-associated fibrosis and on TGF-b1 expression.

METHODS

Colitis was induced by intrarectal instillation of trinitrobenzene sulphonic acid (TNBS) (15 mg⁄mL) while losartan was administered orally daily by gavage (7 mg⁄kg⁄day) for 21 days. Three groups of rats were evaluated: control (n=10); TNBS treated (n=10); and TNBS + losartan treated (n=10). Inflammation and fibrosis of the colon were evaluated by macro- and microscopic score analysis. Colonic TGF-b1 levels was measured using ELISA.

RESULTS

Twenty-one days after induction, losartan significantly improved the macro- and microscopic scores of fibrosis in the colonic wall and reduced TGF-b1 concentration.

CONCLUSIONS

Prophylactic oral administration of losartan reduces the colorectal fibrosis complicating the TNBS-induced chronic colitis, an effect that appears to be mediated by a downregulation of TGF-b1 expression.

Simvastatin attenuates intestinal fibrosis independent of the anti-inflammatory effect by promoting fibroblast/myofibroblast apoptosis in the regeneration/healing process from TNBS-induced colitis

BACKGROUND

Intestinal deformity and stenosis are induced by fibrosis during the process healing of intestinal chronic inflammation in inflammatory bowel disease (IBD). Potent anti-inflammatory treatment of patients with Crohn's disease (CD) may induce fibrous stenosis, and this is often difficult to treat in clinical practice. Therefore, it is necessary to develop a treatment strategy that concomitantly exhibits repair/regenerative and anti-fibrotic effects, in addition to the current anti-inflammatory effect, for the treatment of inflammatory bowel diseases. However, the relationship between the course of inflammatory activity and the healing process and fibrogenesis has not been elucidated; although the complex involvement of various factors in the mechanism of biological fibrosis has been investigated. Simvastatin (SIMV), an HMG-CoA reductase inhibitor, exhibits anti-inflammatory and anti-fibrotic effects. The current study established a model of the regeneration/healing process from TNBS-induced colitis and investigated the anti-inflammatory and anti-fibrotic effects of SIMV.

SUBJECTS AND METHODS

Four groups of TNBS-induced colitis model were prepared using male SJL/J mice: A: Normal control group, B: control group, and C and D: treatment groups. The mucosal healing process was classified into three phases (an early phase: inflammation period, a mid-phase: regeneration promoting period, and a late phase: regeneration-converging period), and inflammation, the expression of fibrosis-related growth factors, and induction of apoptosis of fibrosis-related cells were compared in each period.

RESULTS

(1) The clinical findings showed that SIMV showed anti-inflammatory effects with body weight gain and improvement of epithelial injury in the late phase. Histological (macroscopic/microscopic) improvement was noted in the mid- and late phases. The inflammatory cytokine (TNF-α) level significantly decreased in the mid- and late phases in the high-dose treatment group. (2) SIMV also had anti-fibrotic effects characterized by a dose-dependent decrease in the level of a fibrosis-related growth factor (CTGF) in the early and mid-phases, irrespective of inflammation or changes in the TGF-β(1) level. Dose-dependent induction of apoptosis was noted in both fibroblasts and myofibroblasts from a relatively early stage.

CONCLUSIONS

The results suggested that SIMV induces anti-fibrotic activity that is not directly involved in the anti-inflammatory effect from a relatively early stage the healing process of TNBS-induced colitis.

Inflammation-induced endothelial-to-mesenchymal transition: a novel mechanism of intestinal fibrosis

In addition to mesenchymal cells, endothelial cells may contribute to fibrosis through the process of endothelial-to-mesenchymal transition (EndoMT). We investigated whether human intestinal microvascular endothelial cells (HIMEC) undergo EndoMT and contribute to fibrosis in human and experimental inflammatory bowel disease (IBD). HIMEC were exposed to TGF-β1, IL-1β, and TNF-α or supernatants of lamina propria mononuclear cells (LPMC) and evaluated for morphological, phenotypic, and functional changes compatible with EndoMT. Genomic analysis was used to identify transcription factors involved in the transformation process. Evidence of in situ and in vivo EndoMT was sought in inflamed human and murine intestine. The combination of TGF-β1, IL-1β and TNF-α, or activated LPMC supernatants induced morphological and phenotypic changes consistent with EndoMT with a dominant effect by IL-1. These changes persisted after removal of the inducing agents and were accompanied by functional loss of acetylated LDL-uptake and migratory capacity, and acquisition of de novo collagen synthesis capacity. Sp1 appeared to be the main transcriptional regulator of EndoMT. EndoMT was detected in microvessels of inflammatory bowel disease (IBD) mucosa and experimental colonic fibrosis of Tie2-green fluorescent protein (GFP) reporter-expressing mice. In conclusion, chronic inflammation induces transdifferentiation of intestinal mucosal microvascular cells into mesenchymal cells, suggesting that the intestinal microvasculature contributes to IBD-associated fibrosis through the novel process of EndoMT.