Exploring Asphodelus microcarpus as a source of xanthine oxidase inhibitors: Insights from in silico and in vitro studies.

Xanthine oxidase (XO) plays a critical role in purine catabolism, catalyzing the conversion of hypoxanthine to xanthine and xanthine to uric acid, contributing to superoxide anion production. This process is implicated in various human diseases, particularly gout. Traditional XO inhibitors, such as allopurinol and febuxostat, while effective, may present side effects. Our study focuses on Asphodelus microcarpus, a plant renowned for traditional anti-inflammatory uses. Recent investigations into its phenolic-rich flowers, notably abundant in luteolin derivatives, reveal its potential as a natural source of XO inhibitors. In the present research, XO inhibition by an ethanolic flowers extract from A. microcarpus is reported. In silico docking studies have highlighted luteolin derivatives as potential XO inhibitors, and molecular dynamics support that luteolin 7-O-glucoside has the highest binding stability compared to other compounds and controls. In vitro studies confirm that luteolin 7-O-glucoside inhibits XO more effectively than the standard inhibitor allopurinol, with an IC50 value of 4.8 µg/mL compared to 11.5 µg/mL, respectively. These findings underscore the potential therapeutic significance of A. microcarpus in managing conditions related to XO activity. The research contributes valuable insights into the health-promoting properties of A. microcarpus and its potential application in natural medicine, presenting a promising avenue for further exploration in disease management.

Adherence to Mediterranean Diet and Diet Quality in Patients with Inflammatory Bowel Disease: A Single-Center, Observational, Case-Control Study.

The nutritional status in inflammatory bowel disease (IBD) is often impaired, and adherence to the Mediterranean diet (MedDiet) remains under-investigated. The aim of this study was to assess diet quality (DQ) and adherence to MedDiet in a cohort of Sardinian IBD patients. We conducted a case-control study in which 50 Crohn's disease (CD) and 50 ulcerative colitis (UC) patients were matched with 100 healthy controls each. The Diet Quality Index (DQI-I) and Medi-Lite were used to assess DQ and adherence to MedDiet, respectively. Subgroup analysis by disease characteristics and use of advanced therapies were also carried out. DQI-I scored significantly lower in IBD, independently of disease localization and behavior (CD) and disease extent (UC): [DQI-I: CD 34.5 (IQR 33-37) vs. CTRL 40 (IQR 38.5-43) p < 0.0001; UC 34.5 (IQR 33-37) vs. CTRL 42 (IQR 40-44) p < 0.0001]. Medi-Lite scores were significantly lower in stricturing and ileo-colonic CD and in extensive UC: [Medi-Lite CD 7.5 (IQR 7-9)] vs. CTRL 9 (IQR 7-10) p = 0.0379]; [UC 8 (IQR7-10) vs. CTRL 9 (IQR 8-10.5) p = 0.0046]. IBD patients had a low DQ independently of disease type and phenotype. Patients with ileo-colonic stenosing CD or extensive UC had lower MedDiet adherence, suggesting that its benefits may be mitigated by low acceptance in specific subgroups.

Timing of proper introduction, optimization and maintenance of anti-TNF therapy in IBD: Results from a Delphi consensus.

BACKGROUND: Crohn's disease and ulcerative colitis are inflammatory bowel diseases (IBDs) with a rapidly growing worldwide incidence. The last decades presented rapid progress in pharmacological treatment leading in many cases to clinical and endoscopic remission, including biological treatment with anti-TNF agents. AIM: The exact timing of introduction, optimization and maintenance of anti-TNF therapy in IBDs is not thoroughly covered in current guidelines. METHODS: We used the Delphi panel methodology to gather the IBD experts' views and achieve consensus for clinical recommendations on introducing and maintaining anti-TNF therapy for patients with IBDs. RESULTS: Twelve recommendations achieved a high level of consensus in two assessment rounds by 52 (1st round) and 47 (2nd round) IBD experts. CONCLUSION: In many clinical situations, the early use of anti-TNF therapy is recommended. Nowadays, the cost-efficacy profile of anti-TNF biosimilars makes them the first-line drug in a substantial proportion of patients, thus providing the opportunity to increase access to biological therapy.

Personalize, participate, predict, and prevent: 4Ps in inflammatory bowel disease.

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is a complex, immune-mediated, disorder which leads to several gastrointestinal and systemic manifestations determining a poor quality of life, disability, and other negative health outcomes. Our knowledge of this condition has greatly improved over the last few decades, and a comprehensive management should take into account both biological (i.e., disease-related, patient-related) and non-biological (i.e., socioeconomic, cultural, environmental, behavioral) factors which contribute to the disease phenotype. From this point of view, the so called 4P medicine framework, including personalization, prediction, prevention, and participation could be useful for tailoring ad hoc interventions in IBD patients. In this review, we discuss the cutting-edge issues regarding personalization in special settings (i.e., pregnancy, oncology, infectious diseases), patient participation (i.e., how to communicate, disability, tackling stigma and resilience, quality of care), disease prediction (i.e., faecal markers, response to treatments), and prevention (i.e., dysplasia through endoscopy, infections through vaccinations, and post-surgical recurrence). Finally, we provide an outlook discussing the unmet needs for implementing this conceptual framework in clinical practice.

Comparison of two strategies for the management of postoperative recurrence in Crohn's disease patients with one clinical risk factor: A multicentre IG-IBD study.

BACKGROUND: The management of postoperative recurrence (POR) in Crohn's disease (CD) after ileo-colonic resection is a highly debated topic. Prophylactic immunosuppression after surgery is currently recommended in the presence of at least one clinical risk factor. OBJECTIVE: Our aim was to determine whether early immunosuppression can be avoided and guided by endoscopy in CD patients with only one risk factor. METHODS: CD patients with only one risk factor for POR, including previous intestinal resection, extensive small intestine resection (>50 cm), fistulising phenotype, history of perianal disease, and active smoking, were retrospectively included. Two groups were formed based on whether immunosuppression was started immediately after surgery ("prophylaxis group") or guided by endoscopy ("endoscopy-driven group"). Primary endpoints were rates of any endoscopic recurrence (Rutgeerts ≥ i2a) and severe endoscopic recurrence (i4) within 12 months after surgery. Secondary outcomes were clinical recurrence rates at 6, 12 and 24 months after surgery. RESULTS: A total of 195 patients were enroled, of whom 61 (31.3%) received immunoprophylaxis. No differences between immunoprophylaxis and the endoscopy-driven approach were found regarding any endoscopic recurrence (36.1% vs. 45.5%, respectively, p = 0.10) and severe endoscopic recurrence (9.8% vs. 15.7%, respectively, p = 0.15) at the first endoscopic evaluation. Clinical recurrence rates were also not statistically different (p = 0.43, p = 0.09, and p = 0.63 at 6, 12, and 24 months, respectively). CONCLUSIONS: In operated CD patients with only one risk factor for POR, immediate immunoprophylaxis does not decrease the rate of early clinical and endoscopic recurrence. Prospective studies are needed to confirm our results.

Use of biologics for the management of Crohn's disease: IG-IBD clinical guidelines based on the GRADE methodology.

A cure for Crohn's disease (CD), a chronic inflammatory disease of the gastrointestinal tract of unknown etiology, is not available, so patients require lifelong management to keep inflammation under control. The therapeutic armamentarium has expanded with approval of several biological drugs, including infliximab, adalimumab, vedolizumab and ustekinumab - monoclonal antibodies that target different inflammatory pathways - and darvadstrocel, a suspension of expanded human allogeneic, adipose-derived, mesenchymal stromal cells for the treatment of refractory complex perianal fistula. Notwithstanding existing practice guidelines on medical therapy for CD, the Italian Group for the Study of Inflammatory Bowel Disease felt the need to issue new guidelines focused on the use of biologics for managing the intestinal manifestations of CD and based on the GRADE methodology. This document presents recommendations regarding six clinical settings, from the induction to the maintenance of clinical remission, and from optimization and de-escalation of treatments to dealing with perianal CD and post-operative recurrence. The 19 evidence-based statements are supported by information on the quality of the evidence, agreement rate among panel members, and panel comments mainly based on evidence from real world studies.

Clinical and epidemiological features of ulcerative colitis patients in Sardinia, Italy: Results from a multicenter study.

BACKGROUND: There are little data on the epidemiological and clinical features of adult patients with ulcerative colitis (UC) in the different Italian regions, mainly derived from the absence of a national registry. This prevents correct interpretation of the disease burden. AIM: To assess the main clinical and epidemiological features of adult patients diagnosed with UC in Sardinia, Italy. METHODS: We performed a multicenter, observational, cross-sectional study that included adult patients with UC enrolled in seven gastroenterology unit centers in Sardinia. Data were obtained from the patients' medical records and from a questionnaire administered at the inclusion visit. RESULTS: Four hundred and forty-two patients with UC were included. The median age at diagnosis was 39 years (interquartile range 28-48). After a median disease duration of 10 years, 53 patients experienced proximal extension of proctitis or left-sided colitis. Seventy-five patients developed extraintestinal manifestations. Nineteen patients (4.3%) developed cancer: two with colorectal cancer and seventeen with extracolonic cancers. Mesalazine (5-ASA) remains the mainstay of treatment for UC. Overall, 95 patients (21.5%) were treated with one or more biologic agents, whereas 15 patients (3.4%) underwent surgery, mostly colectomy. CONCLUSION: Our results provide important insights into the clinical and epidemiological features of patients with UC, and while waiting for a national Italian registry, present eligible data on the UC population in Sardinia.

Advanced imaging and Crohn's disease: An overview of clinical application and the added value of artificial intelligence.

PURPOSE: The purpose of this narrative review is to describe the clinical applications of advanced computed tomography (CT) and magnetic resonance (MRI) techniques in patients affected by Crohn's disease (CD), giving insights about the added value of artificial intelligence (AI) in this field. METHODS: We performed a literature search comparing standardized and advanced imaging techniques for CD diagnosis. Cross-sectional imaging is essential for the identification of lesions, the assessment of active or relapsing disease and the evaluation of complications. RESULTS: The studies reviewed show that new advanced imaging techniques and new MRI sequences could be integrated into standard protocols, to achieve a reliable quantification of CD activity, improve the lesions' characterization and the evaluation of therapy response. These promising tools are: dual-energy CT (DECT) post-processing techniques, diffusion-weighted MRI (DWI-MRI), dynamic contrast-enhanced MRI (DCE-MRI), Magnetization Transfer MRI (MT-MRI) and CINE-MRI. Furthermore, AI solutions show a potential when applied to radiological techniques in these patients. Machine learning (ML) algorithms and radiomic features prove to be useful in improving the diagnostic accuracy of clinicians and in attempting a personalized medicine approach, stratifying patients by predicting their prognosis. CONCLUSIONS: Advanced imaging is crucial in the diagnosis, lesions' characterisation and in the estimation of the abdominal involvement in CD. New AI developments are promising tools that could support doctors in the management of CD affected patients.

From inflammation to colitis-associated colorectal cancer in inflammatory bowel disease: Pathogenesis and impact of current therapies.

The risk of colorectal cancer (CRC) is higher in patients with inflammatory bowel disease (IBD). Population-based data from patients with ulcerative colitis (UC) estimate that the risk of CRC is approximately 2- to 3-fold that of the general population; patients with Crohn's disease appear to have a similar increased risk. However, the true extent of colitis-associated cancer (CAC) in undertreated IBD is unclear. Data suggest that the size (i.e., severity and extent) and persistence of the inflammatory process is largely responsible for the development of CRC in IBD. As patients with IBD and CRC have a worse prognosis than those without a history of IBD, the impact of current therapies for IBD on CAC is of importance. Chronic inflammation of the gut has been shown to increase the risk of developing CAC in both UC and CD. Therefore, control of inflammation is pivotal to the prevention of CAC. This review presents an overview of the current knowledge of CAC in IBD patients, focusing on the role of inflammation in the pathogenesis of CAC and the potential for IBD drugs to interfere with the process of carcinogenesis by reducing the inflammatory process or by modulating pathways directly involved in carcinogenesis.

Multidimensional Impact of Mediterranean Diet on IBD Patients.

BACKGROUND & AIMS: Malnutrition with the accumulation of fat tissue and nonalcoholic fatty liver disease (NAFLD) are conditions associated with inflammatory bowel disease (IBD). Visceral fat and NAFLD-related liver dysfunction can both worsen intestinal inflammation. Because the Mediterranean diet (Md) has been shown to ameliorate both obesity and NAFLD, the aim of this study was to analyze the impact of Md on the nutritional state, liver steatosis, clinical disease activity, and quality of life (QoL) in IBD patients. METHODS: Patients with IBD, both Crohn's disease (CD) and ulcerative colitis (UC), followed Md for 6 months. Their body mass index (BMI), body tissue composition, liver steatosis and function, serum lipid profile, clinical disease activity, and inflammatory biomarkers (C-reactive protein and fecal calprotectin) were collected at baseline (T0) and compared with those obtained after 6 months (T180) to evaluate the impact of Md. RESULTS: One hundred forty-two IBD patients, 84 UC and 58 CD, followed Md for 6 months. At T180, diet-adherent CD and UC improved BMI (UC -0.42, P = 0.002; CD -0.48, P = 0.032) and waist circumference (UC -1.25 cm, P = 0.037; CD -1.37 cm, P = 0.041). Additionally, the number of patients affected by liver steatosis of any grade was significantly reduced in both groups (UC T0 31 of 84 [36.9%] vs T180 18 of 84 [21.4%], P = 0.0016; CD T0 27 of 58 [46.6%] vs T180 18 of 58 [31.0%], P < 0.001) after dietary intervention. Finally, after 6 months of the diet, fewer UC and CD patients with stable therapy had active disease (UC T0 14 of 59 [23.7%] vs T180 4 of 59 [6.8%], P = 0.004; CD T0 9 of 51 [17.6%] vs T180 2 of 51 [3.0%], P = 0.011) and elevated inflammatory biomarkers. Mediterranean diet improved QoL in both UC and CD, but neither serum lipid profile nor liver function were modified by the diet. CONCLUSIONS: A significant reduction of malnutrition-related parameters and liver steatosis was observed in both CD and UC patients after short-term dietary intervention based on the adoption of Md, and this was associated with a spontaneous improvement of disease activity and inflammatory markers.

Tumor Infiltrating Regulatory T Cells in Sporadic and Colitis-Associated Colorectal Cancer: The Red Little Riding Hood and the Wolf.

Regulatory T cells represent a class of specialized T lymphocytes that suppress unwanted immune responses and size the activation of the immune system whereby limiting collateral damages in tissues involved by inflammation. In cancer, the accumulation of Tregs is generally associated with poor prognosis. Many lines of evidence indicate that Tregs accumulation in the tumor microenvironment (TME) suppresses the immune response against tumor-associated antigens (TAA), thus promoting tumor progression in non-small cell lung carcinoma (NSLC), breast carcinoma and melanoma. In colorectal cancer (CRC) the effect of Tregs accumulation is debated. Some reports describe the association of high number of Tregs in CRC stroma with a better prognosis while others failed to find any association. These discordant results stem from the heterogeneity of the immune environment generated in CRC in which anticancer immune response may coexists with tumor promoting inflammation. Moreover, different subsets of Tregs have been identified that may exert different effects on cancer progression depending on tumor stage and their location within the tumor mass. Finally, Tregs phenotypic plasticity may be induced by cytokines released in the TME by dysplastic and other tumor-infiltrating cells thus affecting their functional role in the tumor. Here, we reviewed the recent literature about the role of Tregs in CRC and in colitis-associated colorectal cancer (CAC), where inflammation is the main driver of tumor initiation and progression. We tried to explain when and how Tregs can be considered to be the "good" or the "bad" in the colon carcinogenesis process on the basis of the available data concluding that the final effect of Tregs on sporadic CRC and CAC depends on their localization within the tumor, the subtype of Tregs involved and their phenotypic plasticity.

Immunological Variables Associated With Clinical and Endoscopic Response to Vedolizumab in Patients With Inflammatory Bowel Diseases.

BACKGROUND AND AIMS: Vedolizumab [VDZ] is a monoclonal antibody directed against the α4ß7 integrin heterodimer, approved for patients with inflammatory bowel diseases [IBD]. This study aimed at identifying immunological variables associated with response to vedolizumab in patients with ulcerative colitis [UC] and Crohn's disease [CD]. METHODS: This is a phase IV explorative prospective interventional trial. IBD patients received open-label VDZ at Weeks 0, 2, 6, and 14. Patients with a clinical response at Week 14 were maintained with VDZ up to Week 54. At Weeks 0 and 14, their peripheral blood was obtained and endoscopy with biopsies was performed. The Week 14 clinical response and remission, Week 54 clinical remission, and Week 14 endoscopic response were evaluated as endpoints of the study. The expression of surface markers, chemokine receptors, and α4ß7 heterodimer in peripheral blood and lamina propria lymphocytes was assessed by flow cytometry. A panel of soluble mediators was assessed in sera at baseline and at Week 14 by 45-plex. RESULTS: A total of 38 IBD patients [20 UC, 18 CD] were included in the study. At Week 14, the clinical response and remission rates were 87% and 66%, respectively. Higher baseline levels of circulating memory Th1 cells were strongly associated with clinical response at Week 14 [p = 0.0001], whereas reduced baseline levels of lamina propria memory Th17 and Th1/17 cells were associated with endoscopic response. Immunological clusters were found to be independently associated with vedolizumab outcomes at multivariable analysis. A panel of soluble markers, including IL17A, TNF, CXCL1, CCL19 for CD and G-CSF and IL7 for UC, associated with vedolizumab-induced Week 54 clinical remission. CONCLUSIONS: The results of this exploratory study uncovered a panel of circulating and mucosal immunological variables associated with response to treatment with vedolizumab.

Are we choosing wisely for inflammatory bowel disease care? The IG-IBD choosing wisely campaign.

BACKGROUND: The "Choosing Wisely" campaigns have the aim of promoting a better clinician-patient relationship. AIMS: The Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD) conducted a choosing wisely campaign for IBD. METHODS: Ten IG-IBD panellists conducted the campaign through a modified Delphi process. All IG-IBD members were asked to submit five statements starting with "Do not…" addressing any IBD-related procedure or treatment the necessity of which should be questioned. All recommendations were evaluated by the panellists who prioritised each item. The top ten recommendations were prioritised again by IG-IBD members, and the top five recommendations were identified. RESULTS: 110 members (mean age 42 ±â€¯12; 62 males) participated in the campaign. The top five recommendations were as follow: 1. Do not use corticosteroids for maintenance therapy, or without a clear indication; 2. Do not forget venous thromboembolism prophylaxis in hospitalised patients with active disease; 3. Do not treat perianal Crohn's disease with biologics without prior surgical evaluation; 4. Do not discontinue IBD-related medications during pregnancy unless specifically indicated; 5. Do not delay surgery. CONCLUSION: The IG-IBD promoted a campaign with a bottom-up approach, identifying five recommendations that could be useful for providing a better IBD care, especially among non-IBD experts.

Use of biosimilars in inflammatory bowel disease: a position update of the Italian Group for the Study of Inflammatory Bowel Disease (IG-IBD).

The first infliximab biosimilar for the treatment of inflammatory bowel disease (IBD) was introduced in 2013, and today eight anti-TNF alpha biosimilars (three for infliximab and five for adalimumab) have been approved and licensed by the European Medicines Agency. Biosimilars present great potential in terms of cost saving and possible consequential reinvestment in the health care system. The increasing knowledge about the process of biosimilar development and use in IBD and the publication of many prospective clinical studies and real-life clinical experiences have progressively changed the point of view of IBD physicians. In the present position paper, the Italian Group for the Study of Inflammatory Bowel Disease present and discuss their updated statements and positions on this topic, with emphasis on the concepts of biosimilarity and extrapolation across indications, safety and immunogenicity, interchangeability and switching, automatic substitution, and, finally, patient education about biosimilars.

Outcome in ulcerative colitis after switch from adalimumab/golimumab to infliximab: A multicenter retrospective study.

BACKGROUND: Anti-TNF therapies infliximab (IFX), adalimumab (ADA), and golimumab (GOL) are approved for treating moderate to severe ulcerative colitis (UC). In UC, only the switch from IFX to ADA has been investigated, reaching no more than 10-43% remission rates at 12 months. AIM: Of the present study was to investigate disease outcome after a switch from subcutaneous (SC) agents to the intravenous (IV) agent (IFX). METHODS: In this retrospective multicentre study, we analysed the charts of UC patients unresponsive/intolerant or with secondary loss of response (LOR) to ADA or GOL who were switched to IFX. We evaluated clinical response and remission together with adverse events at 3, 6, and 12 months follow-up. RESULTS: Seventy-six patients were included; 38 patients started ADA and 38 started GOL for a mean therapy duration of 6 ±â€¯6 months. Indications for switch were adverse events in 3%, primary failure in 79%, and LOR in 18% of patients. Clinical remission was reached by 47%, 50%, and 77% of patients, respectively. Patients that switched for LOR did numerically, but not statistically, better than patients who switched for primary failure. CONCLUSIONS: Our data show a superior remission rate in SC to IV anti-TNF switch in UC compared to the IV to SC switch reported in literature.

CCL20 Is Negatively Regulated by TGF-ß1 in Intestinal Epithelial Cells and Reduced in Crohn's Disease Patients With a Successful Response to Mongersen, a Smad7 Antisense Oligonucleotide.

BACKGROUND AND AIMS: The chemokine CCL20 is over-produced in epithelium of Crohn's disease [CD] patients and contributes to recruiting immune cells to inflamed gut. Tumour necrosis factor-α [TNF-α] is a powerful inducer of CCL20 in intestinal epithelial cells. In CD, high levels of Smad7 block the activity of transforming growth factor-ß1 [TGF-ß1], a negative regulator of TNF signalling. We investigated whether intestinal epithelial cell-derived CCL20 is negatively regulated by TGF-ß1 and whether Smad7 knock-down reduces CCL20 in CD. METHODS: CCL20 was evaluated in NCM460, a normal colonic epithelial cell line, stimulated with TGF-ß1 and TNF-α, and in Smad7 over-expressing NCM460 cells. CCL20 and Smad7 expression were assessed in sections of CD intestinal specimens by immunochemistry, and in CD colonic explants treated with mongersen, a Smad7 antisense oligonucleotide. CCL20 was examined in serum samples taken from 95 of 166 active CD patients receiving mongersen or placebo for 2 weeks and participating in a phase II, multicentre, double-blind, placebo-controlled study. RESULTS: CCL20 expression was increased by TNF-α, and this effect was inhibited by TGF-ß1 in NCM460 cells, but not in Smad7 over-expressing NCM460 cells. In CD, epithelium CCL20 and Smad7 co-localised, and treatment of CD explants with mongersen reduced CCL20 production. During follow-up, in responders to mongersen, serum CCL20 levels significantly decreased, whereas patients without response/remission to mongersen and placebo patients did not have change in CCL20. CONCLUSIONS: TGF-ß1 reduces intestinal epithelial cell-derived CCL20 production, an effect abrogated by Smad7. CD patients responding to mongersen demonstrated a reduction in serum CCL20.

Activation of TGF-ß-induced non-Smad signaling pathways during Th17 differentiation.

Although transforming growth factor-ß (TGF-ß) has been shown to positively regulate the development of murine T helper type 17 (Th17) cells, which of the intracellular signaling pathways are involved is controversial. We examined Smad-dependent and -independent signaling molecules downstream of the TGF-ß receptor (TGFßR) involved in Th17 differentiation of naive murine CD4(+)CD62L(+) T cells. During Th17 differentiation of wild-type T cells, Smad2/3 was phosphorylated, indicating activation of the canonical Smad pathway. T cells lacking TGFßRII did not differentiate into Th17, whereas T cells treated with a TGFßRI kinase inhibitor (SB-431542) or overexpression of inhibitory Smad7 retained a low amount of Th17 polarization despite absent Smad2/3 phosphorylation. Using protein antibody arrays we found an increase of expression and phosphorylation of the following Smad-independent signaling molecules in Th17-polarized wild-type T cells: AKT1(Tyr474), AKT2 (Ser474), ERK1-p44/42 MAPK(Tyr204), mTOR(Thr2446), p38 MAPK(Thr180), Rac1/cdc42(Ser71), SAPK/JNK(Tyr185) and SP1(Thr739). Pharmacological inhibition of AKT/mammalian target of rapamycin (mTOR) signaling with rapamycin or LY294002 decreased Th17 differentiation of wild-type T cells, and completely abolished interleukin-17 production in T cells with overexpression of Smad7. Rapamycin and LY294002 also decreased induced regulatory T cell differentiation, but only had minor additive effects to Smad7 overexpression. Finally, inhibitors of mitogen-activated protein kinase (MAPK) blocked in vitro polarization of Th17 cells. Our data show that Smad-dependent and -independent intracellular pathways contribute to murine Th17 differentiation.

Inhibition of colitis by IL-25 associates with induction of alternatively activated macrophages.

BACKGROUND: Interleukin (IL)-25, a Th2-related factor, inhibits the synthesis of inflammatory cytokines by macrophages and attenuates experimental colitis in mice. The mechanism underlying the counterregulatory effect of IL-25, however, remains unknown. Since Th2-cytokines can abrogate inflammatory pathways by inducing alternatively activated macrophages (AAMs), we evaluated whether AAMs are involved in the IL-25-mediated anticolitic effect. METHODS: AAM-related markers were evaluated in peritoneal and lamina propria mononuclear cells of mice with or without 2,4,6-trinitrobenzenesulphonic acid (TNBS)-induced colitis treated with IL-25 and/or neutralizing IL-4, IL-13, and transforming growth factor beta 1 (TGF-ß1) antibodies. Peritoneal AAMs induced in vivo by injecting mice with IL-25 were transferred to mice with TNBS colitis. Finally, we assessed the in vitro effect of IL-25 on the alternative activation of peritoneal F4/80+ cells. RESULTS: IL-25 enhanced the expression of AAM-related markers in F4/80(+) cells infiltrating the peritoneum and colon of naïve and colitic mice. Peritoneal F4/80(+) cells isolated from IL-25-treated mice reduced the severity of TNBS colitis when injected intraperitoneally to recipient mice. Since IL-25 did not directly induce AAM in vitro and in vivo in mice, IL-25 administration enhanced the expression of IL-4, IL-13, and TGF-ß1, which are known to promote AAM differentiation, we finally assessed whether such cytokines were involved in the IL-25-driven AAM induction. Blockade of IL-4, IL-13, and TGF-ß1 with neutralizing antibodies in mice did not inhibit the stimulatory effect of IL-25 on AAM gene expression. CONCLUSIONS: The IL-25-mediated anticolitic effect is associated with induction of AAMs, a subset of macrophages with antiinflammatory properties.

Involvement of interleukin-21 in the regulation of colitis-associated colon cancer.

Chronic inflammation is a major driving force in the development of cancer in many tissues, but the array of factors involved in this neoplastic transformation are not well understood. We have investigated the role of interleukin (IL)-21 in colitis-associated colon cancer (CAC), as this cytokine is overexpressed in the gut mucosa of patients with ulcerative colitis (UC), a chronic inflammatory disease associated with colon cancer. IL-21 was increased in the gut of patients with UC-associated colon cancer, and in mice with CAC induced by azoxymethane (AOM) and dextran sulfate sodium (DSS). After AOM+DSS treatment, IL-21 KO mice showed reduced mucosal damage, reduced infiltration of T cells, and diminished production of IL-6 and IL-17A. IL-21-deficient mice also developed fewer and smaller tumors compared with wild-type (WT) mice. Absence of IL-21 reduced signal transducer and activator of transcription 3 activation in tumor and stromal cells. Administration of a neutralizing IL-21 antibody to WT mice after the last DSS cycle decreased the colonic T cell infiltrate and the production of IL-6 and IL-17A and reduced the number of tumors. These observations indicate that IL-21 amplifies an inflammatory milieu that promotes CAC, and suggest that IL-21 blockade may be useful in reducing the risk of UC-associated colon cancer.

Intestinal inflammation and colorectal cancer: a double-edged sword?

Chronic inflammation is thought to be the leading cause of many human cancers including colorectal cancer (CRC). Accordingly, epidemiologic and clinical studies indicate that patients affected by ulcerative colitis and Crohn's disease, the two major forms of inflammatory bowel disease, have an increased risk of developing CRC. In recent years, the role of immune cells and their products have been shown to be pivotal in initiation and progression of colitis-associated CRC. On the other hand, activation of the immune system has been shown to cause dysplastic cell elimination and cancer suppression in other settings. Clinical and experimental data herein reviewed, while confirming chronic inflammation as a risk factor for colon carcinogenesis, do not completely rule out the possibility that under certain conditions the chronic activation of the mucosal immune system might protect from colonic dysplasia.