Predictors of fibrostenotic Crohn's disease

Emodin reduces intestinal fibrosis in rats with TNBS-induced colitis

AIM: To investigate the anti-fibrotic effects of emodin in rats with experimental colitis, and to explore the possible mechanisms.

METHODS: Rats with colitis induced with trinitrobenzene sulphonic acid (TNBS) were used as the model of intestinal fibrosis. Thirty-four rats were randomly divided into normal group, model group and emodin group. Colitis was induced with TNBS in rats of the model group and emodin group. Rats in the emodin group were gavaged with 40 mg/kg of emodin daily, and the other groups were gavaged with an equal volume of 0.9% NaCl solution. Body weight loss and changes in stool and activities were observed, and DAI was calculated. At the end of the experiment, colon tissue samples were collected, and the general and histological scores were given. The injury and fibrosis of the colon were detected by HE staining and Masson collagen staining, respectively. Expression of transforming growth factor (TGF)-β1, collagenⅠ, collagen Ⅲ, Smad3 and α-SMA was determined by FQ-PCR.

RESULTS: Compared to the model group, the general condition, general and histological scores, and fibrosis were improved significantly in the emodin group. Expression of TGF-β1, collagenⅠ, collagen Ⅲ, Smad3 and α-SMA in colonic mucosa in the emodin group were significantly lower than that in the model group (1.27 ± 0.78 vs 4.56 ± 3.14; 0.60 ± 0.59 vs 2.15 ± 1.22; 0.92 ± 1.38 vs 3.34 ± 1.47; 3.11 ± 2.81 vs 8.77 ± 6.40; 0.87 ± 0.62 vs 2.40 ± 1.15, all P < 0.05), while expression of E-cad was higher in the emodin group (1.01 ± 0.34 vs 0.30 ± 0.23, P < 0.05).

CONCLUSION: Emodin reduces intestinal fibrosis in rats with TNBS-induced colitis possibly by down-regulation of TGF-β1/Smad3 signaling and inhibition of epithelial-mesenchymal transition.

Crucial steps in the natural history of inflammatory bowel disease

Inflammatory bowel diseases (IBD), including ulcerative colitis (UC) and Crohn’s disease (CD), are chronic, progressive and disabling disorders. Over the last few decades, new therapeutic approaches have been introduced which have led not only to a reduction in the mortality rate but also offered the possibility of a favorable modification in the natural history of IBD. The identification of clinical, genetic and serological prognostic factors has permitted a better stratification of the disease, thus allowing the opportunity to indicate the most appropriate therapy. Early treatment with immunosuppressive drugs and biologics has offered the opportunity to change, at least in the short term, the course of the disease by reducing, in a subset of patients with IBD, hospitalization and the need for surgery. In this review, the crucial steps in the natural history of both UC and CD will be discussed, as well as the factors that may change their clinical course. The methodological requirements for high quality studies on the course and prognosis of IBD, the true impact of environmental and dietary factors on the clinical course of IBD, the clinical, serological and genetic predictors of the IBD course (in particular, which of these are relevant and appropriate for use in clinical practice), the impact of the various forms of medical treatment on the IBD complication rate, the role of surgery for IBD in the biologic era, the true magnitude of risk of colorectal cancer associated with IBD, as well as the mortality rate related to IBD will be stressed; all topics that are extensively discussed in separate reviews included in this issue of World Journal of Gastroenterology.

Cellular and molecular mechanisms of intestinal fibrosis

Fibrosis is a chronic and progressive process characterized by an excessive accumulation of extracellular matrix (ECM) leading to stiffening and/or scarring of the involved tissue. Intestinal fibrosis may develop in several different enteropathies, including inflammatory bowel disease. It develops through complex cell, extracellular matrix, cytokine and growth factor interactions. Distinct cell types are involved in intestinal fibrosis, such as resident mesenchymal cells (fibroblasts, myofibroblasts and smooth muscle cells) but also ECM-producing cells derived from epithelial and endothelial cells (through a process termed epithelial- and endothelial-mesenchymal transition), stellate cells, pericytes, local or bone marrow-derived stem cells. The most important soluble factors that regulate the activation of these cells include cytokines, chemokines, growth factors, components of the renin-angiotensin system, angiogenic factors, peroxisome proliferator-activated receptors, mammalian target of rapamycin, and products of oxidative stress. It soon becomes clear that although inflammation is responsible for triggering the onset of the fibrotic process, it only plays a minor role in the progression of this condition, as fibrosis may advance in a self-perpetuating fashion. Definition of the cellular and molecular mechanisms involved in intestinal fibrosis may provide the key to developing new therapeutic approaches.

Endoscopic dilation is an efficacious and safe treatment of intestinal strictures in Crohn's disease

BACKGROUND

Bowel strictures are a major cause of morbidity, hospitalisation and surgery in Crohn's disease.

AIM

We report short- and long-term efficacy and safety of endoscopic balloon dilation of strictures due to Crohn's disease.

METHODS

Retrospective study of patients who underwent endoscopic balloon dilation between 1987 and 2009.

RESULTS

We performed 776 dilations, of which 621 (80%) were on anastomotic strictures, in 178 patients (94 women) with Crohn's disease. At first dilation, median (IQR) age of patients was 45 (37-56) years and disease duration 16 (8-22) years. Technical success rate was 689/776 (89%). A subset of 75 patients from the primary catchment area, with >5-year follow-up, underwent a total of 246 dilations. At 1-year follow-up, 60/75 (80%) patients had undergone no further intervention or one additional dilation only. At 3 and 5 years, corresponding figures were 43/75 (57%) and 39/75 (52%). Cumulative proportions of patients undergoing surgery at 1, 3 and 5 years were 13%, 28% and 36%. Complication rate per procedure for all 178 patients was 41/776 (5.3%), bowel perforation (n = 11, 1.4%), major bleeding requiring blood transfusion (n = 8, 1.0%), minor bleeding (n = 10, 1.3%) and abdominal pain or fever (n = 12, 1.5%). Ten patients underwent surgery due to complications (perforation n = 8, bleeding n = 2). There was no procedure-related mortality.

CONCLUSIONS

Endoscopic balloon dilation is an efficacious and safe alternative to surgical resection of intestinal strictures in Crohn's disease. At 5-year follow-up, 52% of patients required no further or one additional dilation only, whereas 36% had undergone surgical resection. Complication frequency was low.

Long-term alterations of cytokines and growth factors expression in irradiated tissues and relation with histological severity scoring

Purpose

Beside its efficacy in cancer treatment, radiotherapy induces degeneration of healthy tissues within the irradiated area. The aim of this study was to analyze the variations of proinflammatory (IL-1α, IL-2, IL-6, TNF-α, IFN-γ), profibrotic (TGF-β1), proangiogneic (VEGF) and stem cell mobilizing (GM-CSF) cytokines and growth factors in an animal model of radiation-induced tissue degeneration.

Materials and Methods

24 rats were irradiated unilaterally on the hindlimb at a monodose of 30 Gy. Six weeks (n = 8), 6 months (n = 8) and 1 year (n = 8) after irradiation the mediators expression in skin and muscle were analyzed using Western blot and the Bio-Plex® protein array (BPA) technology. Additional histological severity for fibrosis, inflammation, vascularity and cellularity alterations scoring was defined from histology and immnunohistochemistry analyses.

Results

A significant increase of histological severity scoring was found in irradiated tissue. Skin tissues were more radio-sensitive than muscle. A high level of TGF-β1 expression was found throughout the study and a significant relation was evidenced between TGF-β1 expression and fibrosis scoring. Irradiated tissue showed a chronic inflammation (IL-2 and TNF-α significantly increased). Moreover a persistent expression of GM-CSF and VEGF was found in all irradiated tissues. The vascular score was related to TGF-β1 expression and the cellular alterations score was significantly related with the level of IL-2, VEGF and GM-CSF.

Conclusion

The results achieved in the present study underline the complexity and multiplicity of radio-induced alterations of cytokine network. It offers many perspectives of development, for the comprehension of the mechanisms of late injuries or for the histological and molecular evaluation of the mode of action and the efficacy of rehabilitation techniques.

Diagnostic value, clinical utility and pathogenic significance of reactivity to the molecular targets of Crohn's disease specific-pancreatic autoantibodies

Pancreatic autoantibodies (PAB) giving characteristic staining patterns of the exocrine pancreas by indirect immunoflourescence appear to be specific markers of Crohn's disease (CrD), being present in approximately 30% of patients with CrD and in less than 5% of patients with ulcerative colitis (UC). Some studies have suggested that PAB are associated with specific disease phenotypes and that their detection may be of clinical significance. Thorough investigation of the role of PAB in the immunopathogenesis of inflammatory bowel diseases (IBD) has been hampered due to the lack of identity of their antigenic targets. The recent identification of the pancreatic zymogen granule protein 2 (GP2) as the major target of PAB has led to the development of an enzyme immunoassay that helps determine the diagnostic and clinical relevance of antigen-specific immune responses. Recent studies have demonstrated that GP2 is expressed on the apical surface of intestinal membranous cells of the follicle-associated epithelium, and is essential for host-microbial interaction and the initiation of bacteria-specific mucosal immune responses. This review critically discusses recent reports investigating the diagnostic and clinical utility of GP2-specific autoantibody responses in patients with IBD. Hints towards a better understanding of the immunogenicity of GP2 are also provided.