High Smad7 sustains inflammatory cytokine response in refractory coeliac disease.

Refractory coeliac disease (RCD) is a form of coeliac disease (CD) resistant to gluten-free diet and associated with elevated risk of complications. Many effector cytokines over-produced in the gut of patients with RCD are supposed to amplify the tissue-destructive immune response, but it remains unclear if the RCD-associated mucosal inflammation is sustained by defects in counter-regulatory mechanisms. The aim of the present study was to determine whether RCD-related inflammation is marked by high Smad7, an intracellular inhibitor of transforming growth factor-ß1 (TGF-ß1 ) activity. Smad7 was evaluated in duodenal biopsy samples of patients with RCD, patients with active CD, patients with inactive CD and healthy controls by Western blotting, immunohistochemistry and real-time PCR. In the same samples, TGF-ß1 and phosphorylated (p)-Smad2/3 were evaluated by ELISA and immunohistochemistry, respectively. Pro-inflammatory cytokine expression was evaluated in RCD samples cultured with Smad7 sense or antisense oligonucleotide. Smad7 protein, but not RNA, expression was increased in RCD compared with active and inactive CD patients and healthy controls and this was associated with defective TGF-ß1 signalling, as marked by diminished p-Smad2/3 expression. TGF-ß1 protein content did not differ among groups. Knockdown of Smad7 in RCD biopsy samples reduced interleukin-6 and tumour necrosis factor-α expression. In conclusion, in RCD, high Smad7 associates with defective TGF-ß1 signalling and sustains inflammatory cytokine production. These results indicate a novel mechanism by which the mucosal cytokine response is amplified in RCD and suggest that targeting Smad7 can be therapeutically useful in RCD.

Frequency and Cause of Persistent Symptoms in Celiac Disease Patients on a Long-term Gluten-free Diet.

GOALS: To estimate the frequency and cause of nonresponsive celiac disease (CD). BACKGROUND: Treatment of CD is based on life-long adherence to a gluten-free diet (GFD). Some celiac patients experience persistence of symptoms despite a GFD. This condition is defined as nonresponsive CD. STUDY: Celiac patients on a GFD for at least 12 months underwent diet compliance assessment, laboratory tests, breath tests, endoscopic, and histologic evaluations according to the symptoms/signs reported. RESULTS: Seventy of 321 (21.8%) patients had persistent or recurrent symptoms/signs. The cause of symptom persistence was evaluated in 56 of 70 patients. Thirteen of 56 (23%) patients were antiendomysial antibody positive. Among the patients with negative serology, 1 had fibromyalgia, and 3 had evidence that disproved the diagnosis of CD. The remaining 39 patients with negative serology underwent duodenal biopsy sampling, which evidenced histologic alterations in 24 patients. Among the 15 patients with normal histology 3 were lactose intolerant, 9 had irritable bowel syndrome, 2 had gastroesophageal reflux disease, and in 1 patient a cause for the persistent symptom was not identified. In patients with confirmed diagnosis of CD, exposure to dietary gluten was the main cause of persistence of symptoms/signs, and consistently after dietary modification, symptoms resolved in 63% of the patients at later time points during follow-up. CONCLUSION: Nonresponsive CD occurs in nearly one fifth of celiac patients on GFD and its occurrence suggests further investigations to optimize the management of celiac patients.

Analysis of the cytokine profile in the duodenal mucosa of refractory coeliac disease patients.

RCD [refractory CD (coeliac disease)] is characterized by severe symptoms/signs of malabsorption and mucosal damage unresponsive to a GFD (gluten-free diet). The pathogenesis of RCD is not fully understood. In the present paper, we have characterized the mucosal profile of effector cytokines in RCD. Duodenal biopsies were taken from patients with RCD, patients with active CD and normal controls and were analysed for inflammatory cytokines by real-time PCR and ELISA. IFN (interferon)-γ and IL (interleukin)-21 transcripts were increased in active CD patients but not in RCD patients as compared with normal controls, whereas IL-17A RNA was up-regulated in both active CD and RCD. No significant increase in IL-15 transcripts was observed in both active CD and RCD, whereas IL-15 protein was increased in active CD. IL-6 and TNF (tumour necrosis factor)-α were up-regulated only in RCD. As a proof, we present the case of a woman affected by RCD who responded to anti-TNF-α treatment with improvement of malabsorptive symptoms/signs but no healing of mucosal lesions. The findings indicate that the profile of mucosal effector cytokines differs between RCD and active CD and suggest that TNF-α, IL-6 and IL-17A, but not Th1-type cytokines, could drive the detrimental response in this condition.

An overview of the role of innate lymphoid cells in gut infections and inflammation.

Innate lymphoid cells (ILCs) are a group of hematopoietic cells devoid of antigen receptors that have important functions in lymphoid organogenesis, in the defense against extracellular pathogens, and in the maintenance of the epithelial barrier. Three distinct groups of ILCs have been identified on the basis of phenotypic and functional criteria and termed ILCs1, ILCs2, and ILCs3. Specifically, ILCs1 express the transcription factor T-bet and secrete T helper type-1- (Th1-) related cytokines, ILCs2 are dependent on the transcription factor RORα and express Gata-3 and the chemokine receptor homologous molecule (CRTH2) and produce Th2-related cytokines, and ILCs3 express the transcription factor RORγt and synthesize interleukin- (IL-) 17, IL-22, and, under specific stimuli, interferon-γ. ILCs represent a relatively small population in the gut, but accumulating evidence suggests that these cells could play a decisive role in orchestrating both protective and detrimental immune responses. In this review, we will summarize the present knowledge on the distribution of ILCs in the intestinal mucosa, with particular focus on their role in the control of both infections and effector cytokine response in immune-mediated pathologies.

Pyoderma gangrenosum in refractory celiac disease: a case report.

BACKGROUND: Pyoderma gangrenosum is an inflammatory neutrophilic dermatosis characterized by painful cutaneous ulcerations and often associated with systemic inflammatory and neoplastic diseases. Here we report the first case of pyoderma gangrenosum in a patient with refractory celiac disease. CASE PRESENTATION: A 52-year-old woman with a previously diagnosed refractory celiac disease resistant to steroids and immunosuppressive drugs presented to our hospital for a rapidly growing, painful inflammatory skin lesion of the left leg. Physical examination revealed a painful lesion with focal ulceration, necrosis and pus discharge with active inflammatory borders at the external part of the left leg. Histological evaluation of a skin biopsy and analysis of inflammatory cytokines and matrix-degrading proteases in lesional skin samples confirmed the clinical suspicion of pyoderma gangrenosum. Treatment with oral prednisone was rapidly followed by a complete healing of the skin lesion but no improvement of symptoms/signs of malabsorption. CONCLUSION: Treatment of the patient with systemic steroids healed the skin lesion without improving the underlying refractory celiac disease. This observation raises the possibility that refractory celiac disease and pyoderma gangrenosum may be immunologically different.

Inflammatory cytokines: from discoveries to therapies in IBD.

Introduction: Although the etiology of inflammatory bowel diseases (IBD) remains unknown, accumulating evidence suggests that the intestinal tissue damage in these disorders is due to a dynamic interplay between immune cells and non-immune cells, which is mediated by cytokines produced within the inflammatory microenvironment. Areas covered: We review the available data about the role of inflammatory cytokines in IBD pathophysiology and provide an overview of the therapeutic options to block the function of such molecules. Expert opinion: Genome studies, in vitro experiments with patients' samples and animal models of colitis, have largely advanced our understanding of how cytokines modulate the ongoing mucosal inflammation in IBD. However, not all the cytokines produced within the damaged gut seem to play a major role in the amplification and perpetuation of the IBD-associated inflammatory cascade. Indeed, while some of the anti-cytokine compounds are effective in some subgroups of IBD patients, others have no benefit. In this complex scenario, a major unmet need is the identification of biomarkers that can predict response to therapy and facilitate a personalized therapeutic approach, which maximizes the benefits and limits the adverse events.

Targeting IL-23 in Crohn's disease.

INTRODUCTION: Interleukin (IL)-23, a cytokine produced by antigen presenting cells, targets both T cells and non-T cell types with the downstream effect of enhancing inflammatory pathways. Genome-wide association studies and data from human and mouse models of intestinal inflammation support the pathogenic role of IL-23 in Crohn's disease (CD), an immune-mediated disorder that can involve any part of the gastrointestinal tract. Areas covered: This review summarizes the available data on the role of IL-23 in CD and discusses the therapeutic relevance of blocking the function of IL-23 in this disorder. Expert commentary: The use of biologic drugs, such as anti-TNF and anti-integrins, has largely improved the management of CD patients. However, a significant proportion of CD patients taking these drugs continue to experience symptoms and have inflammation in the gut, thus suggesting a need for new agents, which block other inflammatory signals. Data emerging from trials with IL-23p40 and p19 blockers indicate that IL-23 is a valid therapeutic target. More studies are needed to optimize the therapeutic regimens, ascertain whether selective inhibition of IL-23p19 is more advantageous than blockade of p40, a subunit shared by IL-12 and IL-23, and evaluate the long-term risk of these approaches.

Oligonucleotide-Based Therapies for Inflammatory Bowel Disease.

The growing understanding of the immunopathogenesis of inflammatory bowel diseases (IBDs) has contributed to the identification of new targets whose expression/activity can be modulated for therapeutic purposes. Several approaches have been employed to develop selective pharmaceutical compounds; among these, antisense oligonucleotides (ASOs) or synthetic oligonucleotides represent a valid option for inhibiting or enhancing, respectively, the expression/function of molecules that have been implicated in the control of IBD-related inflammation. In this context, data have been accumulated for the following compounds: alicaforsen, an ASO targeting intercellular adhesion molecule-1, a transmembrane glycoprotein that regulates rolling and adhesion of leukocytes to inflamed intestine; DIMS0150 and BL-7040, two oligonucleotides that enhance Toll-like receptor-9 activity; Mongersen, an ASO that inhibits Smad7, thereby restoring transforming growth factor-ß1/Smad-associated signaling; STNM01, a double-stranded RNA oligonucleotide silencing carbohydrate sulfotransferase, an enzyme involved in fibrogenic processes, and hgd40, a specific DNAzyme inhibiting expression of the transcription factor GATA3. In this article, we review the rationale and the available data relative to the use of these agents in IBD. Although pre-clinical and phase II trials in IBD support the use of oligonucleotide-based therapies for treating the pathogenic process occurring in the gut of patients with these disorders, further work is needed to establish whether and which patients can benefit from specific ASOs and identify biomarkers that could help optimize treatment.

Follistatin-like protein 1 sustains colon cancer cell growth and survival.

Follistatin-like protein 1 (FSTL1) is a secreted glycoprotein, which controls several physiological and pathological events. FSTL1 expression is deregulated in many tumors, but its contribution to colon carcinogenesis is not fully understood. Here, we investigated the expression and functional role of FSTL1 in colorectal cancer (CRC). A significant increase of FSTL1 was seen in human CRC as compared to the surrounding non-tumor tissues and this occurred at both RNA and protein level. Knockdown of FSTL1 in CRC cells with a specific antisense oligonucleotide (AS) reduced expression of regulators of the late G1 phase, such as phosphorylated retinoblastoma protein, E2F-1, cyclin E and phospho-cyclin-dependent kinase-2, and promoted accumulation of cells in the G1 phase of the cell cycle thus resulting in diminished cell proliferation. Consistently, recombinant FSTL1 induced proliferation of normal intestinal epithelial cells through an ERK1/2-dependent mechanism. Cell cycle arrest driven by FSTL1 AS in CRC cells was accompanied by activation of caspases and subsequent induction of apoptosis. Moreover, FSTL1 knockdown made CRC cells more susceptible to oxaliplatin and irinotecan-induced death. Data indicate that FSTL1 is over-expressed in human CRC and suggest a role for this protein in favouring intestinal tumorigenesis.

Reciprocal Regulation Between Smad7 and Sirt1 in the Gut.

In inflammatory bowel disease (IBD) mucosa, there is over-expression of Smad7, an intracellular inhibitor of the suppressive cytokine transforming growth factor-ß1, due to post-transcriptional mechanisms that enhance Smad7 acetylation status thus preventing ubiquitination-mediated proteosomal degradation of the protein. IBD-related inflammation is also marked by defective expression of Sirt1, a class III NAD+-dependent deacetylase, which promotes ubiquitination-mediated proteosomal degradation of various intracellular proteins and triggers anti-inflammatory signals. The aim of our study was to determine whether, in IBD, there is a reciprocal regulation between Smad7 and Sirt1. Smad7 and Sirt1 were examined in mucosal samples of IBD patients and normal controls by Western blotting and immunohistochemistry, and Sirt1 activity was assessed by a fluorimetric assay. To determine whether Smad7 is regulated by Sirt1, normal or IBD lamina propria mononuclear cells (LPMC) were cultured with either Sirt1 inhibitor (Ex527) or activator (Cay10591), respectively. To determine whether Smad7 controls Sirt1 expression, ex vivo organ cultures of IBD mucosal explants were treated with Smad7 sense or antisense oligonucleotide. Moreover, Sirt1 expression was evaluated in LPMC isolated from Smad7-transgenic mice given dextran sulfate sodium (DSS). Upregulation of Smad7 was seen in both the epithelial and lamina propria compartments of IBD patients and this associated with reduced expression and activity of Sirt1. Activation of Sirt1 in IBD LPMC with Cay10591 reduced acetylation and enhanced ubiquitination-driven proteasomal-mediated degradation of Smad7, while inhibition of Sirt1 activation in normal LPMC with Ex527 increased Smad7 expression. Knockdown of Smad7 in IBD mucosal explants enhanced Sirt1 expression, thus suggesting a negative effect of Smad7 on Sirt1 induction. Consistently, mucosal T cells of Smad7-transgenic mice contained reduced levels of Sirt1, a defect that was amplified by induction of DSS colitis. The data suggest the existence of a reciprocal regulatory mechanism between Smad7 and Sirt1, which could contribute to amplify inflammatory signals in the gut.

Knockdown of Smad7 With a Specific Antisense Oligonucleotide Attenuates Colitis and Colitis-Driven Colonic Fibrosis in Mice.

Background: In Crohn's disease (CD), the pathogenic immune response is associated with high Smad7, an inhibitor of TGF-ß1 signaling. Smad7 knockdown with Mongersen, a specific antisense oligonucleotide-containing compound, restores TGF-ß1 activity leading to inhibition of inflammatory signals and associates with clinical benefit in CD patients. As TGF-ß1 is pro-fibrogenic, it remains unclear whether Mongersen-induced Smad7 inhibition increases the risk of intestinal fibrosis. We assessed the impact of Smad7 inhibition on the course of colitis-driven intestinal fibrosis in mice. Methods: BALB/c mice were rectally treated with increasing doses of trinitrobenzene sulfonic acid (TNBS) for 8 or 12 weeks. The effect of oral Smad7 antisense or control oligonucleotide, administered to mice starting from week 5 or week 8, respectively, on mucosal inflammation and colitis-associated colonic fibrosis was assessed. Mucosal samples were analyzed for Smad7 by immunoblotting and immunohistochemistry, TGF-ß1 by enzyme-linked immunosorbent assay, and collagen by immunohistochemistry. Results: TNBS-induced chronic colitis was associated with colonic deposition of collagen I and fibrosis, which were evident at week 8 and became more pronounced at week 12. TNBS treatment enhanced Smad7 in both colonic epithelial and lamina propria mononuclear cells. Colitic mice treated with Smad7 antisense oligonucleotide exhibited reduced signs of colitis, less collagen deposition, and diminished fibrosis. These findings were associated with diminished synthesis of TGF-ß1 and reduced p-Smad3 protein expression. Conclusion: Attenuation of colitis with Smad7 antisense oligonucleotide limits development of colonic fibrosis.

Smad7 knockdown activates protein kinase RNA-associated eIF2α pathway leading to colon cancer cell death.

Upregulation of Smad7, an inhibitor of transforming growth factor-ß1 (TGF-ß1), occurs in sporadic colorectal cancer (CRC) and knockdown of Smad7 inhibits CRC cell growth, a phenomenon that associates with decreased expression of cell division cycle 25 homolog A and arrest of cells in the S phase of the cell cycle. These findings occur in CRC cells unresponsive to TGF-ß1, thus suggesting the existence of a Smad7-mediated TGF-ß1-independent mechanism that controls CRC cell behavior. Here we show that Smad7 inhibition with a specific Smad7 antisense oligonucleotide upregulates eukaryotic translation initiation factor 2α (eIF2α) phosphorylation, a transcription factor involved in the regulation of cell cycle arrest and induction of cell death, and induces activating transcription factor 4 (ATF4) and CCAAT/enhancer binding protein homology protein (CHOP), two downstream targets of eIF2α. Among the upstream kinases that control eIF2α phosphorylation, the serine-threonine protein kinase RNA (PKR), but not general control non-derepressible 2 (GCN2) and protein kinase RNA-like endoplasmic reticulum kinase (PERK), is activated by Smad7 knockdown. PKR silencing abolishes Smad7 antisense-induced eIF2α phosphorylation and ATF4/CHOP induction, thereby preventing Smad7 antisense-driven cell death. Smad7 inhibition diminishes interaction of PKR with protein kinase inhibitor p58 (p58IPK), a cellular inhibitor of PKR, but does not change the expression and/or activity of other factors involved in the control of PKR activation. These findings delineate a novel mechanism by which Smad7 knockdown promotes CRC cell death.

Celiac Disease-Related Inflammation Is Marked by Reduction of Nkp44/Nkp46-Double Positive Natural Killer Cells.

INTRODUCTION AND AIM: Natural killer (NK) cells are a first line of defence against viruses and down-regulation of NK cell cytotoxic receptors represents one of the strategies by which viruses escape the host's immune system. Since onset of celiac disease (CD), a gluten-driven enteropathy, has been associated with viral infections, we examined whether CD-associated inflammation is characterized by abnormal distribution of NK cell receptors involved in recognition of viral-infected cells. MATERIALS AND METHODS: Intraepithelial mononuclear cells, isolated from duodenal biopsies of active and inactive CD patients and healthy controls (CTR) and jejunal specimens of obese subjects undergoing gastro-intestinal bypass, were analysed for NK cell markers by flow-cytometry. Expression of granzyme B, interleukin (IL)-22 and tumor necrosis factor (TNF)-α was as assessed in freshly isolated and toll-like receptor (TLR) ligand-stimulated cells. RESULTS: The percentages of total NK cells and NKT cells did not significantly differ between CD patients and CTR. In active CD, the fractions of NKp30+ NK cells, NKG2D+ NK cells and NKG2D+ NKT cells were significantly increased as compared to inactive CD patients and CTR. In contrast, CD-associated inflammation was marked by diminished presence of NKG2A+ NK cells and NKG2A+ NKT cells. The fractions of NK cells and NKT cells expressing either NKp44 or NKp46 did not differ between CD and controls, but in CD less NK cells and NKT cells co-expressed these receptors. NKp44/NKp46-double positive cells produced granzyme B and IL-22 but not TNF-α and responded to TLR ligands with enhanced expression of granzyme B. CONCLUSIONS: These data indicate that active phase of CD associates with reduced presence of NKp44/NKp46-double positive NK cells and NKT cells in the epithelial compartment.

The TGF-ß/Smad System in IBD Pathogenesis.

In Crohn's disease and ulcerative colitis, the tissue-damaging destructive immune response is sustained by defects of counterregulatory mechanisms, which normally attenuate inflammatory pathways and promote repair of mucosal injury. One such mechanism involves transforming growth factor-ß1 (TGF-ß1), a cytokine that is produced by multiple cell types and targets both immune and nonimmune cells. Both in vitro and in vivo studies strongly support the role of TGF-ß1 as a negative regulator of mucosal inflammation and indicate that defective production/activity of this cytokine can lead to the development of or exacerbate colitis. Interestingly, in the inflamed intestine of patients with inflammatory bowel disease, TGF-ß1 expression is upregulated but TGF-ß1-mediated immunosuppression is markedly impaired because of high Smad7, an intracellular inhibitor of TGF-ß1-associated signaling. Consistently, knockdown of Smad7 with a specific antisense oligonucleotide restores TGF-ß1 activity, thus leading to decreased production of inflammatory cytokines in both colitic mice and inflammatory bowel disease patients and attenuates clinical activity in Crohn's disease patients. In this article, we review data supporting the role of Smad7 in the pathogenesis of inflammatory bowel disease and discuss whether inhibition of Smad7 is therapeutically useful in Crohn's disease and how the benefit/risk of such an intervention should be monitored in the patients.

Antisense approach to inflammatory bowel disease: prospects and challenges.

Despite the great success of anti-tumour necrosis factor-based therapies, the treatment of Crohn's disease (CD) and ulcerative colitis (UC) still remains a challenge for clinicians, as these drugs are not effective in all patients, their efficacy may wane with time, and their use can increase the risk of adverse events and be associated with the development of new immune-mediated diseases. Therefore, new therapeutic targets are currently being investigated both in pre-clinical studies and in clinical trials. Among the technologies used to build new therapeutic compounds, the antisense oligonucleotide (ASO) approach is slowly gaining space in the field of inflammatory bowel diseases (IBDs), and three ASOs have been investigated in clinical trials. Systemic administration of alicaforsen targeting intercellular adhesion molecule-1, a protein involved in the recruitment of leukocytes to inflamed intestine, was not effective in CD, even though the same compound was of benefit when given as an enema to UC patients. DIMS0150, targeting nuclear factor (NF) κB-p65, a transcription factor that promotes pro-inflammatory responses, was very promising in pre-clinical studies and is currently being tested in clinical trials. Oral mongersen, targeting Smad7, an intracellular protein that inhibits transforming growth factor (TGF)-ß1 activity, was safe and well tolerated by CD patients, and the results of a phase II clinical trial showed the efficacy of the drug in inducing clinical remission in patients with active disease. In this leading article, we review the rationale and the clinical data available regarding these three agents, and we discuss the challenge of using ASOs in IBD.

Targeting integrins and adhesion molecules to combat inflammatory bowel disease.

: The etiologies of Crohn's disease and ulcerative colitis, the 2 major forms of inflammatory bowel disease in humans, remain unknown, but experimental studies suggest that inflammatory bowel disease results from interaction between environmental and genetic factors, which promotes an exaggerated and inappropriately controlled inflammatory response that is directed against normal components of the gut flora. There is also evidence that tissue damage is due to a dynamic interplay between immune and nonimmune cells, and recruitment of lymphocytes from the blood stream to the gut wall is crucial for amplifying and sustaining the ongoing mucosal inflammation. These advances have led to the development of several compounds blocking gut homing of effector lymphocytes, which have recently been used or are now ready to move into clinical practice. This article summarizes the recent data on the use of integrin-targeting and adhesion molecule-targeting therapeutics to attenuate the detrimental inflammatory response in inflammatory bowel disease.

Proteinase activated-receptors-associated signaling in the control of gastric cancer.

Gastric cancer (GC) is the fourth most common cancer in the world and the second cause of cancer-related death. Gastric carcinogenesis is a multifactorial process, in which environmental and genetic factors interact to activate multiple intracellular signals thus leading to uncontrolled growth and survival of GC cells. One such a pathway is regulated by proteinase activated-receptors (PARs), seven transmembrane-spanning domain G protein-coupled receptors, which comprise four receptors (i.e., PAR-1, PAR-2, PAR-3, and PAR-4) activated by various proteases. Both PAR-1 and PAR-2 are over-expressed on GC cells and their activation triggers and/or amplifies intracellular pathways, which sustain gastric carcinogenesis. There is also evidence that expression of either PAR-1 or PAR-2 correlates with depth of wall invasion and metastatic dissemination and inversely with the overall survival of patients. Consistently, data emerging from experimental models of GC suggest that both these receptors can be important targets for therapeutic interventions in GC patients. In contrast, PAR-4 levels are down-regulated in GC and correlate inversely with the aggressiveness of GC, thus suggesting a negative role of this receptor in the control of GC. In this article we review the available data on the expression and role of PARs in GC and discuss whether manipulation of PAR-driven signals may be useful for interfering with GC cell behavior.

Sampling of proximal and distal duodenal biopsies in the diagnosis and monitoring of celiac disease.

BACKGROUND: Since celiac disease-associated mucosal lesions are patchy, the diagnosis of the disease requires histological evaluation of multiple duodenal biopsies. AIM: To examine whether adequate biopsy sampling in either the bulb or distal duodenum is sufficient to diagnose celiac disease. METHODS: Twenty-five patients with positive celiac disease-specific serology and 17 patients with negative serology, who were on a gluten-containing diet, and 13 celiac disease patients on a gluten-free diet were consecutively and prospectively enrolled. Mucosal damage, anti-transglutaminase-2 IgA deposits, interferon-γ, interleukin-17A and interleukin-15 transcripts were evaluated in bulb and distal duodenal biopsies. RESULTS: All patients with positive celiac disease-specific serology exhibited villous atrophy in both duodenal sites. In this group, mucosal anti-transglutaminase-2 IgA deposits were found in 24/25 (96%) bulb samples and 22/25 (88%) distal duodenal samples. No villous atrophy was documented in patients with negative serology. Interferon-γ and interleukin-17A were over-expressed in both duodenal sites of patients with villous atrophy, unlike patients with normal duodenal morphology (p<0.001). Among treated celiac disease patients, 2 (15.4%) had villous atrophy exclusively in the bulb and 6 (46.2%) had minimal histological abnormalities at both sites. CONCLUSION: Sampling in the bulb and distal duodenum could be sufficient to diagnose/exclude celiac disease.

Smad7 antisense oligonucleotide-based therapy for inflammatory bowel diseases.

The aetiology of both Crohn's disease and ulcerative colitis, the major forms of inflammatory bowel diseases in human beings, remains unknown. However, compelling evidence suggests that the associated pathological process in inflammatory bowel disease is driven by an excessive immune response directed against normal components of the bacterial microflora and marked by defects in counter-regulatory mechanisms, such as those involving transforming growth factor-ß1. Indeed, a diminished activity of transforming growth factor-ß1, as indicated by a reduced phosphorylation of Smad3, a signalling molecule associated with the activated transforming growth factor-ß receptor, is evident in the inflamed gut of inflammatory bowel disease patients and this alteration is due to high Smad7, an intracellular inhibitor of Smad3 phosphorylation. Consistently, silencing of Smad7 with a specific antisense oligonucleotide restores transforming growth factor-ß1/Smad3 signalling, thereby leading to inhibition of inflammatory cytokine production and attenuation of experimental colitis in mice. These findings together with the demonstration that Smad7 antisense oligonucleotide is safe and well-tolerated in patients with Crohn's disease indicate that Smad7 antisense oligonucleotide-based pharmaceutical compounds could enter the therapeutic armamentarium of these disorders. In this article we review the available data supporting the pathogenic role of Smad7 in the gut and discuss why Smad7 antisense therapy could help dampen the mucosal inflammation in inflammatory bowel disease.

Distinct profiles of effector cytokines mark the different phases of Crohn's disease.

OBJECTIVE: Crohn's Disease (CD)-associated inflammation is supposed to be driven by T helper (Th)1/Th17 cell-derived cytokines, even though there is evidence that the mucosal profile of cytokine may vary with the evolution of the disease. We aimed at comparing the pattern of effector cytokines in early and established lesions of CD. DESIGN: Mucosal samples were taken from the neo-terminal ileum of CD patients undergoing ileocolonic resection, with (early lesions) or without post-operative recurrence, and terminal ileum of CD patients with long-standing disease undergoing intestinal resection (established lesions). Inflammatory cell infiltrate was examined by immunofluorescence and cytokine expression was analysed by real-time PCR, flow-cytometry and ELISA. RESULTS: Before the appearance of endoscopic lesions, the mucosa of the neo-terminal ileum contained high number of T cells and macrophages, elevated levels of Th1-related cytokines and TNF-α and slightly increased IL-17A expression. Transition from this stage to endoscopic recurrence was marked by abundance of Th1 cytokines, marked increase in IL-17A, and induction of IL-6 and IL-23, two cytokines involved in the control of Th17 cell responses. In samples with established lesions, there was a mixed Th1/Th17 response with no TNF-α induction. Expression of IL-4 and IL-5 was up-regulated in both early and established lesions even though the fraction of IL-4-producing cells was lower than that of cells producing either interferon-γ or IL-17A. CONCLUSIONS: Distinct mucosal profiles of cytokines are produced during the different phases of CD. A better understanding of the cytokines temporally regulated in CD tissue could help optimize therapeutic interventions in CD.