Fully covered versus partially covered self-expandable metal stents for palliation of distal malignant biliary obstruction: a systematic review and meta-analysis.

BACKGROUND AND AIMS: Self-expandable metal stents (SEMSs) are standardly used for distal malignant biliary obstruction (dMBO). Although data suggest that covered versus uncovered SEMSs increase the time to recurrent biliary obstruction (TRBO), no data are available for fully covered (FC) versus partially covered (PC) designs. METHODS: PubMed, Scopus, and Cochrane databases were screened up to January 2023 for studies concerning dMBO treated by an FC- or PC-SEMS and describing adverse events (AEs), recurrences, or TRBO for specific design subpopulations. Pooled proportions or means were calculated using a random-effects model. Several subanalyses were preplanned, including a subanalysis restricted to prospective studies and unresectable diseases. Heterogeneity and publication bias were explored. Standardized differences (d-values) were calculated between groups. RESULTS: From 1290 records, 62 studies (3327 using FC-SEMSs and 2322 using PC-SEMSs) were included. FC- versus PC-SEMSs showed negligible differences in the rate of total AEs (12% vs 9.9%) and all specific AEs, including cholecystitis (2.5% vs 2.6%). In a subanalysis restricted to prospective studies and unresectable diseases, the rate of RBO was comparable between FC-SEMSs (27.3% [95% confidence interval {CI}, 23.7-31.2], I2 = 35.34%) and PC-SEMSs (25.3% [95% CI, 20.2-30.7], I2 = 85.09%), despite small differences (d-values between .186 and .216) in the rate of ingrowth (.5% vs 2.9%) favoring FC-SEMSs and migration (9.8% vs 4.3%) favoring PC-SEMSs. TRBO was shorter for FC-SEMSs (238 days [95% CI, 191-286], I2 = 63.1%) versus PC-SEMSs (369 days [95% CI, 290-449], I2 = 71.9%; d-value = .116). CONCLUSIONS: Despite considerable heterogeneity and small standardized differences, PC-SEMSs consistently exhibited longer TRBO than FC-SEMSs across analyses, without any other differences in AE rates, potentially proposing PC-SEMSs as the standard comparator and TRBO as the primary outcome for future randomized studies on dMBO. (Clinical trial registration number: CRD42023393965.).

Efficacy and safety of endoscopic ultrasound-guided hepaticogastrostomy: a meta-regression analysis.

BACKGROUND: Endoscopic ultrasound-guided hepaticogastrostomy (EUS-HGS) is a valid option for EUS-guided biliary drainage that has been increasingly used in the last decade. The aims of this study were to provide a systematic review with meta-analysis and meta-regression of the features and outcomes of this procedure. METHODS: The MEDLINE, Scopus, Web of Science, and Cochrane databases were searched for literature pertinent to EUS-HGS. Meta-analysis of the proportions and meta-regression of potential modifiers of the main outcome measures were applied. The main outcome was technical success; secondary outcomes were clinical success and procedure-related adverse events (AEs). RESULTS: 33 studies, including 1644 patients, were included in the meta-analysis. Malignant biliary obstruction (MBO) was the underlying cause in almost all cases (99.6%); the main indications for EUS-HGS were duodenal/papillary invasion (34.8%), surgically altered anatomy (18.4%), and hilar stenosis (16.0%). The pooled technical success of EUS-HGS was 97.7% (95%CI 96.1%-99.0%; I 2 = 0%), the intention-to-treat clinical success rate was 88.1% (95%CI 84.7%-91.2%; I 2 = 33.9%), and procedure-related AEs occurred in 12.0% (95%CI 9.8%-14.5%; I 2 = 20.4%), with cholangitis/sepsis (2.8%) and bleeding (2.3%) the most frequent. The rate of procedure-related AEs was lower with the use of dedicated stents on univariable meta-regression analysis. Meta-regression showed that technical success and clinical success rates were modified by the centers' experience (>4/year). CONCLUSIONS: EUS-HGS represents an effective and safe procedure for EUS-guided biliary drainage in patients with MBO. Future studies should address the impact of center experience, patient selection, and the use of dedicated stents to improve performance of this technique.

Endoscopic Ultrasound-Guided Drainage of Pancreatic Fluid Collections: Not All Queries Are Already Solved.

Pancreatic fluid collections (PFCs) are well-known complications of acute pancreatitis. The overinfection of these collections leads to a worsening of the prognosis with an increase in the morbidity and mortality rate. The primary strategy for managing infected pancreatic necrosis (IPN) or symptomatic PFCs is a minimally invasive step-up approach, with endosonography-guided (EUS-guided) transmural drainage and debridement as the preferred and less invasive method. Different stents are available to drain PFCs: self-expandable metal stents (SEMSs), double pigtail stents (DPPSs), or lumen-apposing metal stents (LAMSs). In particular, LAMSs are useful when direct endoscopic necrosectomy is needed, as they allow easy access to the necrotic cavity; however, the rate of adverse events is not negligible, and to date, the superiority over DPPSs is still debated. Moreover, the timing for necrosectomy, the drainage technique, and the concurrent medical management are still debated. In this review, we focus attention on indications, timing, techniques, complications, and particularly on aspects that remain under debate concerning the EUS-guided drainage of PFCs.

Endoscopic Management of Postoperative Esophageal and Upper GI Defects-A Narrative Review.

Anastomotic defects are deleterious complications after either oncologic or bariatric surgery, leading to high morbidity and mortality. Besides surgical revision in early stages or instable patients, endoscopic treatment has become the mainstay. To date, many options for endoscopic treatment in this setting exist, including fully covered metal stent placement, endoscopic vacuum therapy (EVT), endoscopic internal drainage with pigtail placement (EID), leak closure with through the scope or over the scope clips, endoluminal suturing, fibrin glue sealing and a combination of all these techniques. Current evidence is mostly based on retrospective single and multicenter studies. No guidelines exist in this important field. Treatment options have to be chosen upon each case individually, taking into account clinical and anatomic criteria, such as timing, size, infectious wound complications and hemodynamic stability. Local expertise and availability of treatment devices need to be taken into account whenever choosing a treatment strategy. This review aimed to present current treatment options in terms of effectiveness, advantages and disadvantages in order to guide the clinician for his decision making. Additionally, we aimed to provide a treatment algorithm.

Endoscopic Management of Bleeding in Altered Anatomy after Upper Gastrointestinal Surgery.

Postoperative non variceal upper gastrointestinal haemorrhage may occur early or late and affect a variable percentage of patients-up to about 2%. Most cases of intraluminal bleeding are an indication for urgent Esophagogastroduodenoscopy (EGD) and require endoscopic haemostatic treatment. In addition to the approach usually adopted in non-variceal upper haemorrhages, these cases may be burdened with difficulties in terms of anastomotic tissue, angled positions, and the risk of further complications. There is also extreme variability related to the type of surgery performed, in the context of oncological disease or bariatric surgery. At the same time, the world of haemostatic devices available in digestive endoscopy is increasing, meeting high efficacy rates and attempting to treat even the most complex cases. Our narrative review summarises the current evidence in terms of different approaches to endoscopic haemostasis in upper bleeding in altered anatomy after surgery, proposing an up-to-date guidance for endoscopic clinicians and at the same time, highlighting areas of future scientific research.

A Serological Biomarker of Laminin Gamma 1 Chain Degradation Reflects Altered Basement Membrane Remodeling in Crohn's Disease and DSS Colitis.

BACKGROUND: The laminin gamma 1 chain (LMγ1) is abundant along the crypt-villus axis in the intestinal basement membrane. AIMS: We investigated whether a serological biomarker of laminin degradation was associated with disease activity in patients with Crohn's disease (CD) and in rats with dextran sulfate sodium (DSS)-induced colitis. METHODS: Serum samples from CD patients (n = 43), healthy subjects (n = 19), and Sprague Dawley rats receiving 5-6% DSS water for five days and regular drinking water for 11 days were included in this study. The LG1M biomarker, a neo-epitope degradation fragment of the LMγ1 chain generated by matrix metalloproteinases-9 (MMP-9), was measured in serum to estimate the level of laminin degradation. RESULTS: Serum LG1M was elevated in CD patients with active and inactive disease compared to healthy subjects (p < 0.0001). LG1M distinguished CD patients from healthy subjects, with an area under the curve (AUC) of 0.81 (p < 0.0001). Serum LG1M was decreased in DSS rats compared to controls 2 days after DSS withdrawal, and increased upon reversal of the disease. CONCLUSIONS: Increased serum LG1M in active and inactive CD patients supports the evidence of altered LM expression in both inflamed and non-inflamed tissue. Moreover, lower LG1M levels in the early healing phase of DSS-induced colitis may reflect ongoing mucosal repair.

Multidimensional Prognostic Index Predicts Clinical Outcome and Mortality in Hospitalised Older Patients with Diverticular Disease.

INTRODUCTION: The Multidimensional Prognostic Index (MPI) is a validated tool for assessing mortality risk in hospitalised patients. We aimed to evaluate whether the MPI predicted mortality and the risk of developing diverticular disease (DD) complications in older patients. METHODS: This is a multicentre study conducted in January 2016-March 2018. All patients with DD aged 65 years and older were included. Patients were stratified into three groups according to MPI groups (1, low risk; 2, moderate risk; 3, high risk). Risk of developing DD complications and mortality rate were assessed. Bivariate models were fitted. RESULTS: One hundred hospitalised patients with DD (mean age 77.9 ± 10.6 years, 53 female patients) were included. Patients with higher MPI groups were more likely to develop DD complications. In particular, 12 (46.2%), 21 (52.5%), and 28 (82.4%) patients with complicated DD were distributed to the MPI 1, MPI 2, and MPI 3 groups (p = 0.0063), respectively. Two patients died in the MPI 1, 4 in the MPI 2, and 29 in the MPI 3 group, with mortality rates of 4.0 per 100 person-year (95% confidence interval [CI] 1.0-15.9), 5.6 (95% CI 2.1-15.0), and 89.2 (95% CI 62-130), respectively (log-rank test p < 0.001). In bivariate analysis, after adjustment for age >80 years, Charlson Comorbidity Index >4, DD complications, and the presence of thromboembolism, higher MPI group was independently associated with higher mortality. Those in the MPI 3 group experienced a greater risk of 1-year hospital readmission (p < 0.001). CONCLUSION: MPI predicted mortality in patients with DD and also correlated with the risk of developing DD complications. Studies focussing on possible pathophysiological mechanisms between DD complications and MPI are needed.

Direct-acting antiviral agents and risk of Hepatocellular carcinoma: Critical appraisal of the evidence.

Direct-acting antivirals (DAAs) revolutionized the treatment of chronic HCV-related disease achieving high rates of sustained virological response (SVR), even in advanced cirrhosis, with modest contraindications and a low rate of adverse events. However, the risk of hepatocellular carcinoma (HCC) persists due to the underlying chronic liver disease, both in patients with and without history of HCC. Although some initial studies reported a presumptive high risk of HCC development after DAA therapy, more recent observational studies denied this hypothesis. The residual risk for HCC occurrence after HCV eradication seems being progressively reduced with time after SVR. Data on recurrence of HCC after DAA exposure in patients with previously treated carcinoma initially reported conflicting results too, this being also due to methodological issues in analysis of retrospective multicenter studies. Anyway, current evidence support the use of DAAs in HCV-HCC treated patients, without any higher risk of tumor recurrence linked to antiviral therapy. Less effort has been made to evaluate the efficacy of DAA therapy in patients with untreated active HCC and it has been questioned whether a lower rate of SVR would be obtained among patients with active HCC. Studies conducted in this perspective concluded that HCC status does not influence the likelihood to obtain SVR with DAAs, making DAAs appropriate in HCC-active patients. As far as survival is concerned, recent studies conducted in cirrhotic HCV-related early-stage HCC found that DAAs improved overall survival, a benefit probably due to the reduction of hepatic decompensation.

Prognostic Role of Mismatch Repair Status, Histotype and High-Risk Pathologic Features in Stage II Small Bowel Adenocarcinomas.

BACKGROUND: Small bowel adenocarcinoma is a relatively rare cancer, often diagnosed in an advanced stage. In localized and resectable disease, surgery alone or in combination with adjuvant chemotherapy is the mainstay of treatment. In the recently published National Comprehensive Cancer Network Clinical Practice guidelines, criteria for selecting patients with stage II small bowel adenocarcinoma to receive adjuvant chemotherapy are provided, and they are mainly extrapolated from studies on colorectal cancer. PATIENTS AND METHODS: In the present study, we aimed to verify whether mismatch repair deficiency phenotype, high-risk pathologic features (including T4, positive resection margins and a low number of lymph nodes harvested), as well as tumor histologic subtype, were associated with cancer-specific survival in 66 stage II non-ampullary small bowel adenocarcinoma patients, collected through the Small Bowel Cancer Italian Consortium. A central histopathology review was performed. Mismatch repair deficiency was tested by immunohistochemistry for MLH1, MSH2, MSH6 and PMS2, and confirmed by polymerase chain reaction for microsatellite instability. RESULTS: We identified mismatch repair deficiency, glandular/medullary histologic subtype, and celiac disease as significant predictors of favorable cancer-specific survival using univariable analysis with retained significance in bivariable models adjusted for pT stage. Among the high-risk features, only T4 showed a significant association with an increased risk of death; however, its prognostic value was not independent of mismatch repair status. CONCLUSIONS: Mismatch repair protein expression, histologic subtype, association with celiac disease, and, in the mismatch repair proficient subset only, T stage, may help identify patients who may benefit from adjuvant chemotherapy.

Are radiological endpoints surrogate outcomes of overall survival in hepatocellular carcinoma treated with transarterial chemoembolization?

BACKGROUND& AIMS: Time to progression (TTP) and progression-free survival (PFS) are commonly used as surrogate endpoints in oncology trials. We aimed to assess the surrogacy relationship of TTP and PFS with overall survival (OS) in studies of transarterial chemoembolization (TACE) for unresectable hepatocellular carcinoma (u-HCC) by innovative methods. METHODS: A search of databases for studies of TACE for u-HCC reporting both OS and TTP or PFS was performed. Individual patient data were extracted from TTP/PFS and OS Kaplan-Meier curves of TACE arms. Pooled median TTP and OS were obtained from random-effect model. The surrogate relationships of hazard ratios (HRs) and median TTP for OS were evaluated by the coefficient of determination R2 . RESULTS: We identified 13 studies comparing TACE vs systemic therapy or vs TACE plus systemic therapy and including 1932 TACE-treated patients. Pooled median OS was 11.2 months (95% confidence interval [95%CI] 7.9-17.8), and pooled median TTP was 5.4 months (95%CI 3.8-8.0). Heterogeneity among studies was highly significant for both outcomes. The correlation between HR TTP and HR OS was moderate (R2  = 0.65. 95%CI 0.08-0.81). R2 value was 0.04 (95%CI 0.00-0.35) between median TTP and median OS. CONCLUSION: In studies of TACE for u-HCC, the surrogate relationship of radiology-based endpoints with OS is moderate. Multiple endpoints including hepatic decompensation, macrovascular invasion and extrahepatic spread are needed for future trials comparing systemic therapies or combination of TACE with systemic therapies vs TACE alone.

Proteomics signature of autoimmune atrophic gastritis: towards a link with gastric cancer.

BACKGROUND: Autoimmune atrophic gastritis (AAG) is a chronic disease that can progress to gastric cancer (GC). To better understand AAG pathology, this proteomics study investigated gastric proteins whose expression levels are altered in this disease and also in GC. METHODS: Using two-dimensional difference gel electrophoresis (2D-DIGE), we compared protein maps of gastric corpus biopsies from AAG patients and controls. Differentially abundant spots (|fold change|≥ 1.5, P < 0.01) were selected and identified by LC-MS/MS. The spots were further assessed in gastric antrum biopsies from AAG patients (without and with Helicobacter pylori infection) and from GC patients and unaffected first-degree relatives of GC patients. RESULTS: 2D-DIGE identified 67 differentially abundant spots, with 28 more and 39 less abundant in AAG-corpus than controls. LC-MS/MS identified these as 53 distinct proteins. The most significant (adjusted P < 0.01) biological process associated with the less abundant proteins was "tricarboxylic acid cycle". Of the 67 spots, 57 were similarly differentially abundant in AAG-antrum biopsies irrespective of H. pylori infection status. The differential abundance was also observed in GC biopsies for 14 of 28 more abundant and 35 of 39 less abundant spots, and in normal gastric biopsies of relatives of GC patients for 6 and 25 spots, respectively. Immunoblotting confirmed the different expression levels of two more abundant proteins (PDIA3, GSTP gene products) and four less abundant proteins (ATP5F1A, PGA3, SDHB, PGC). CONCLUSION: This study identified a proteomics signature of AAG. Many differential proteins were shared by GC and may be involved in the progression of AAG to GC.

Serum zonulin and its diagnostic performance in non-coeliac gluten sensitivity.

OBJECTIVE: Non-coeliac gluten sensitivity (NCGS) is characterised by intestinal and extraintestinal symptoms related to the ingestion of gluten-containing foods, in the absence of coeliac disease (CD) and wheat allergy. No biomarkers are available to diagnose NCGS and the gold standard double-blind placebo-controlled gluten challenge is clinically impractical. The aim of our work was to investigate the role of serum zonulin as a diagnostic biomarker of NCGS and to develop a diagnostic algorithm. DESIGN: In a multicentre study, we enrolled 86 patients with either self-reported or double-blind confirmed NCGS, 59 patients with diarrhoea-predominant IBS (IBS-D), 15 patients with CD and 25 asymptomatic controls (AC). Zonulin serum levels were assessed and the associated diagnostic power calculated. Clinical and symptomatic data were recorded. The effect of diet on zonulin levels was evaluated in a subgroup of patients with NCGS. RESULTS: Compared with ACs, the NCGS, irrespective of modality of diagnosis, and patients with CD had significantly increased levels of zonulin, as did both NCGS and patients with CD compared with participants with IBS-D. Self-reported NCGS showed increased zonulin levels compared with double-blind confirmed and not-confirmed NCGS. Six-month wheat avoidance significantly reduced zonulin levels only in HLA-DQ2/8-positive participants with NCGS. The diagnostic accuracy of zonulin levels in distinguishing NCGS from IBS-D was 81%. After exclusion of CD, a diagnostic algorithm combining zonulin levels, symptoms and gender improved the accuracy to 89%. CONCLUSION: Zonulin can be considered a diagnostic biomarker in NCGS and combined with demographic and clinical data differentiates NCGS from IBS-D with high accuracy. Wheat withdrawal was associated with a reduction in zonulin levels only in NCGS carrying HLA genotype.

Correction: PD-L1 in small bowel adenocarcinoma is associated with etiology and tumor-infiltrating lymphocytes, in addition to microsatellite instability.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

PD-L1 in small bowel adenocarcinoma is associated with etiology and tumor-infiltrating lymphocytes, in addition to microsatellite instability.

Small bowel adenocarcinomas (SBAs) are often associated with poor prognosis and have limited therapeutic options. Programmed cell death protein-1 (PD-1)/programmed cell death ligand 1 (PD-L1) pathway blockade is an effective treatment in many microsatellite instability-high (MSI-H) solid tumors. We aimed at investigating PD-L1 and PD-1 expression in non-hereditary, non-ampullary SBAs, associated with celiac disease (CeD), Crohn's disease (CrD), or sporadic, recruited through the Small Bowel Cancer Italian Consortium. We assessed PD-L1 and PD-1 by immunohistochemistry in a series of 121 surgically resected SBAs, including 34 CeD-SBAs, 49 CrD-SBAs, and 38 sporadic SBAs. PD-L1 and PD-1 expression was correlated with several clinico-pathological features, such as the etiology, microsatellite instability status, and tumor-infiltrating lymphocyte (TIL) density. The prevalence of PD-L1 positivity according to combined positive score (CPS) was 26% in the whole cohort of SBAs, with significantly (p = 0.001) higher percentage (35%) in both CeD-SBAs and CrD-SBAs in comparison with sporadic SBAs (5%). CPS ≥ 1 SBAs were significantly (p = 0.013) more frequent in MSI-H cases (41%) than in non-MSI-H ones (18%); however, 15 CPS ≥ 1 microsatellite stable SBAs were also identified. CPS ≥ 1 SBAs showed higher TIL and PD-1+ immune cell density, more frequently medullary histotype, as well as a better outcome in comparison with CPS < 1 cases. This study demonstrates an increased proportion of PD-L1+ cases in both CeD-SBAs and CrD-SBAs in comparison with sporadic SBAs. In addition, the identification of a subset of PD-L1+ microsatellite stable SBAs supports the need to ascertain additional biomarkers of response to immune checkpoint inhibitors along with MSI-H.

Targeting T cells in inflammatory bowel disease.

T cells play a pivotal role in the immune response underlying inflammatory bowel disease (IBD) pathogenesis. On this basis, over the past 25 years several drugs have assessed to target T cells in IBD patients. Amongst anti-CD3 antibodies, visilizumab and foralumab did not show clinical efficacy in ulcerative colitis (UC) and Crohn's disease (CD) patients, respectively, whereas otelixizumab has been tested in vitro only. The anti-CD4 BF-5 and cM-T412, and the anti-CD25 basiliximab and daclizumab were not effective in CD and UC patients, respectively. The anti-NKG2D antibody NNC0142-0002 showed clinical benefit in CD patients, in particular in biologic naïve ones, in a randomized, double-blind, parallel-group, placebo-controlled trial. The anti-CD40L M90 and the GSK1349571A blocking calcium release-activated calcium (CRAC) channels, which are involved in the T cell activation and proliferation, were tested only in ex vivo/in vitro experiments. Apart from ustekinumab, all the other drugs targeting T cell-derived cytokines failed. The reinduction of lamina propria T cell apoptosis is a mechanism to modulate T cell survival exploited by cyclosporin A, azathioprine and anti-tumor necrosis factor-α agents, such as infliximab, adalimumab and golimumab. In this article, we review the drugs targeting T cells via surface receptors, via T cell-derived cytokines, via CRAC channels or by inducing apoptosis.

Old and New Lymphocyte Players in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic intestinal inflammatory disorder characterized by diffuse accumulation of lymphocytes in the gut mucosa as a consequence of over-expression of endothelial adhesion molecules. The infiltrating lymphocytes have been identified as subsets of T cells, including T helper (Th)1 cells, Th17 cells, and regulatory T cells. The function of these lymphocyte subpopulations in the development of IBD is well-known, since they produce a number of pro-inflammatory cytokines, such as interferon-γ and interleukin-17A, which in turn activate mucosal proteases, thus leading to the development of intestinal lesions, i.e., ulcers, fistulas, abscesses, and strictures. However, the immune mechanisms underlying IBD are not yet fully understood, and knowledge about the function of newly discovered lymphocytes, including Th9 cells, innate lymphoid cells, mucosal-associated invariant T cells, and natural killer T cells, might add new pieces to the complex puzzle of IBD pathogenesis. This review summarizes the recent advances in the understanding of the role of mucosal lymphocytes in chronic intestinal inflammation and deals with the therapeutic potential of lymphocyte-targeting drugs in IBD patients.

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.

Abnormal thymic stromal lymphopoietin expression in the duodenal mucosa of patients with coeliac disease.

OBJECTIVE: The short isoform of thymic stromal lymphopoietin (TSLP), a cytokine constitutively expressed by epithelial cells, is crucial in preserving immune tolerance in the gut. TSLP deficiency has been implicated in sustaining intestinal damage in Crohn's disease. We explored mucosal TSLP expression and function in refractory and uncomplicated coeliac disease (CD), a T-cell-mediated enteropathy induced by gluten in genetically susceptible individuals. DESIGN: TSLP isoforms-long and short-and receptors-TSLPR and interleukin (IL)-7Rα-were assessed by immunofluorescence, immunoblotting and qRT-PCR in the duodenum of untreated, treated, potential and refractory patients with CD. The ability of the serine protease furin or CD biopsy supernatants to cleave TSLP was evaluated by immunoblotting. The production of interferon (IFN)-γ and IL-8 by untreated CD biopsies cultured ex vivo with TSLP isoforms was also assessed. RESULTS: Mucosal TSLP, but not TSLPR and IL-7Rα, was reduced in untreated CD and refractory CD in comparison to treated CD, potential CD and controls. Transcripts of both TSLP isoforms were decreased in active CD mucosa. Furin, which was overexpressed in active CD biopsies, was able to cleave TSLP in vitro. Accordingly, refractory and untreated CD supernatants showed higher TSLP-degrading capacity in comparison to treated CD and control supernatants. In our ex vivo model, both TSLP isoforms significantly downregulated IFN-γ and IL-8 production by untreated CD biopsies. CONCLUSIONS: Reduced mucosal TSLP expression may contribute to intestinal damage in refractory and untreated CD. Further studies are needed to verify whether restoring TSLP might be therapeutically useful especially in refractory patients with CD.

Interferon-γ is increased in the gut of patients with irritable bowel syndrome and modulates serotonin metabolism.

Mucosal immune activation and altered serotonin metabolism participate in the pathophysiology of irritable bowel syndrome (IBS). However, the reciprocal interplay between these two systems remains unknown. We evaluated the expression and release of interferon (IFN)-γ from the colonic mucosa of patients with IBS and its impact on serotonin reuptake transporter (SERT) gene expression in Caco-2 cells. qPCR was used to evaluate IFN-γ gene expression in colonic mucosal biopsies, whereas IFN-γ protein amount was assessed by ELISA. Colonic T box expressed in T cells (T-bet) and phosphorylated signal transducer and activator of transcription 4 protein amount were evaluated by Western blot. The impact of colonic mucosal mediators on SERT gene expression was evaluated in Caco-2 cells using qPCR. IFN-γ receptor was silenced in Caco-2 cells to determine the effect of IFN-γ released by mucosal biopsies. Compared with asymptomatic controls (ACs), the expression of IFN-γ gene and its transcription factor T-bet were markedly increased in the colonic mucosa of patients with IBS. Compared with ACs, IFN-γ protein tissue levels and its release by mucosal biopsies were significantly increased in IBS. The exposure of Caco-2 cells to IBS supernatants induced a significant decrease in SERT gene expression, independently of IBS subtypes, compared with AC mucosal supernatants. In Caco-2 cells, IFN-γ receptor silencing reversed the reduction of SERT expression evoked by IBS supernatants vs. nonsilenced cell lines. IFN-γ gene, its transcription factor T-bet, IFN-γ protein expression, and its release are increased in the colonic mucosa of patients with IBS and downregulate SERT gene expression in vitro. These results suggest that IFN-γ downregulates SERT expression, hence likely playing a role in altered serotonin metabolism of patients with IBS.