Texture and color enhancement imaging versus high definition white-light endoscopy for detection of colorectal neoplasia: a randomized trial.

BACKGROUND: Texture and color enhancement imaging (TXI) was recently proposed as a substitute for standard high definition white-light imaging (WLI) to increase lesion detection during colonoscopy. This international, multicenter randomized trial assessed the efficacy of TXI in detection of colorectal neoplasia. METHODS: Consecutive patients aged ≥ 40 years undergoing screening, surveillance, or diagnostic colonoscopies at five centers (Italy, Germany, Japan) between September 2021 and May 2022 were enrolled. Patients were randomly assigned (1:1) to TXI or WLI. Primary outcome was adenoma detection rate (ADR). Secondary outcomes were adenomas per colonoscopy (APC) and withdrawal time. Relative risks (RRs) adjusted for age, sex, and colonoscopy indication were calculated. RESULTS: We enrolled 747 patients (mean age 62.3 [SD 9.5] years, 50.2 % male). ADR was significantly higher with TXI (221/375, 58.9 %) vs. WLI (159/372, 42.7 %; adjusted RR 1.38 [95 %CI 1.20-1.59]). This was significant for ≤ 5 mm (RR 1.42 [1.16-1.73]) and 6-9 mm (RR 1.36 [1.01-1.83]) adenomas. A higher proportion of polypoid (151/375 [40.3 %] vs. 104/372 [28.0 %]; RR 1.43 [1.17-1.75]) and nonpolypoid (136/375 [36.3 %] vs. 102/372 [27.4 %]; RR 1.30 [1.05-1.61]) adenomas, and proximal (143/375 [38.1 %] vs. 111/372 [29.8 %]; RR 1.28 [1.05-1.57]) and distal (144/375 [38.4 %] vs. 98/372 [26.3 %]; RR 1.46 [1.18-1.80]) lesions were found with TXI. APC was higher with TXI (1.36 [SD 1.79] vs. 0.89 [SD 1.35]; incident rate ratio 1.53 [1.25-1.88]). CONCLUSIONS: TXI increased ADR and APC among patients undergoing colonoscopy for various indications. TXI increased detection of polyps < 10 mm, both in the proximal and distal colon, and may help to improve colonoscopy quality indicators.

GATA6 Deficiency Leads to Epithelial Barrier Dysfunction and Enhances Susceptibility to Gut Inflammation.

BACKGROUND AND AIMS: Intestinal barrier dysfunction is a hallmark of inflammatory bowel diseases [IBD], but the mechanisms that lead to such a defect are not fully understood. This study was aimed at characterising the factors involved in the defective barrier function in IBD. METHODS: Transcriptome analysis was performed on colon samples taken from healthy controls [CTR] and IBD patients. Expression of GATA-binding factor 6 [GATA6], a transcription factor involved in intestinal epithelial cell differentiation, was evaluated in colon samples taken from CTR and IBD patients by real-time polymerase chain reaction [PCR] and immunohistochemistry. Intestinal sections of wild-type and Gata6del mice, which exhibit a conditional Gata6 deletion in intestinal epithelial cells and which are either left untreated or receive subcutaneous indomethacin or rectal trinitrobenzene sulphonic acid, were stained with haematoxylin and eosin. In parallel, some Gata6del mice received antibiotics to deplete intestinal flora. Mucosal inflammatory cell infiltration and cytokine production were evaluated by flow cytometry and real-time PCR, respectively, and tight junction proteins were examined by immunofluorescence. Intestinal barrier integrity was assessed by fluorescein isothiocyanate [FITC]-dextran assay. RESULTS: Multiple genes involved in cell commitment/proliferation and wound healing were differentially expressed in IBD compared with CTR. Among these, GATA6 was significantly decreased in the IBD epithelium compared with CTR. In mice, conditional deletion of GATA6 in the intestinal epithelium induced primarily epithelial damage, diminished zonula occludens-1 expression, and enhanced intestinal permeability, ultimately resulting in bacteria-driven local immune response and enhanced susceptibility to gut inflammation. CONCLUSIONS: Reduced expression of GATA6 promotes intestinal barrier dysfunction, thus amplifying intestinal inflammatory pathology.

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.

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.

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.

Advances in understanding the role of cytokines in inflammatory bowel disease.

INTRODUCTION: Cytokines represent the key pathophysiologic elements that govern the initiation, progression, and, in some circumstances, the resolution of the inflammation occurring in inflammatory bowel disease (IBD). Areas covered: In this review, we will focus on the main effector and anti-inflammatory cytokines produced in IBD and discuss the results of recent trials in which cytokine-based therapy has been used for treating IBD patients. Expert commentary: The possibility to sample mucosal biopsies from IBD patients and analyze which molecular pathways are prominent during the active phases of the disease and the easy access to various models of experimental colitis has largely advanced our understanding about the role of cytokines in IBD. These progresses have facilitated the development of several therapeutic compounds, which either target inflammatory cytokines or enhance the regulatory function of immunosuppressive cytokines. While some of such drugs are effective in the induction and maintenance of remission of the disease, other compounds are not useful for attenuating the ongoing mucosal inflammation, thus establishing a hierarchical scale of the relevance of cytokines in IBD. Further work is needed to identify biomarkers, which could help personalize cytokine-targeted therapy and minimize potential side effects.

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.

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.

Interleukin-34 sustains pro-tumorigenic signals in colon cancer tissue.

Interleukin-34 (IL-34), a cytokine produced by a wide range of cells, binds to the macrophage colony-stimulating factor receptor (M-CSFR-1) and receptor-type protein-tyrosine phosphatase zeta (PTP-z) and controls myeloid cell differentiation, proliferation and survival. various types of cancers over-express IL-34 but the role of the cytokine in colorectal cancer (CRC) remains unknown. We here investigated the expression and functional role of IL-34 in CRC. A more pronounced expression of IL-34 was seen in CRC samples as compared to matched normal/benign colonic samples and this occurred at both RNA and protein level. Immunohistochemical analysis of CRC tissue samples showed that both cancer cells and lamina propria mononuclear cells over-expressed IL-34. Additionally, CRC cells expressed both M-CSFR-1 and PTP-z, thus suggesting that CRC cells can be responsive to IL-34. Indeed, stimulation of DLD-1 cancer cells with IL-34, but not with MSCF1, enhanced the cell proliferation and cell invasion without affecting cell survival. Analysis of intracellular signals underlying the mitogenic effect of IL-34 revealed that the cytokine enhanced activation of ERK1/2 and pharmacologic inhibition of ERK1/2 abrogated IL-34-driven cell proliferation. Consistently, IL-34 knockdown in HT-29 cells with a specific IL-34 antisense oligonucleotide reduced ERK1/2 activation, cell proliferation and enhanced the susceptibility of cells to Oxaliplatin-induced death. This is the first study showing up-regulation of IL-34 in CRC and suggesting a role for this cytokine in colon tumorigenesis.

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.

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.

Mongersen, an oral Smad7 antisense oligonucleotide, in patients with active Crohn's disease.

In Crohn's disease (CD), the tissue-damaging inflammation is sustained by defects of counter-regulatory mechanisms, which normally inhibit immune-inflammatory signals and promote repair of mucosal injury. In particular, in inflamed gut of CD patients there are elevated levels of Smad7, an intracellular protein that inhibits the function of transforming growth factor (TGF)-ß1. Knockdown of Smad7 with a specific antisense oligonucleotide, named mongersen, restores TGF-ß1 activity thus leading to suppression of inflammatory pathways and resolution of colitis in mice. Consistently, oral administration of mongersen to patients with active CD induces clinical remission. In this article, we review the available data supporting the pathogenic role of Smad7 in CD and discuss the results of recent phase I and II trials assessing the efficacy and safety of mongersen in CD patients.

Tofacitinib for the treatment of ulcerative colitis.

INTRODUCTION: Management of patients with active ulcerative colitis (UC), one of the most frequent inflammatory bowel diseases in human beings, is mainly based on the use of mesalamine and corticosteroids. Since in the long-term, these two drugs may be ineffective in nearly one third of the patients, immunosuppressants and/or biologics are needed to control disease activity. AREAS COVERED: The marked activation of JAK/STAT molecules in inflamed mucosa of UC patients and the demonstration that UC-associated mucosal injury is driven by soluble factors that signal through JAK/STAT pathways led to investigation of JAK inhibitors for the treatment of active UC. Tofacitinib, an oral inhibitor of the cytokine-driven JAK-STAT signalling cascade, has recently been proposed for the treatment of moderate-to-severe UC. Phase 2 study showed the efficacy of tofacitinib to induce clinical and endoscopic improvement/remission and the safety profile of the drug. Herein the authors review this compound. EXPERT OPINION: The results obtained from clinical trials with tofacitinib suggest that this drug could be a new treatment option for patients with moderate to severe UC. However, further experimentation is needed to assess the efficacy of this drug in selected subgroups of patients as well as to maintain remission and to determine the long-term safety profile of the drug.

Impact of endoscopic ultrasound-guided fine-needle aspiration and multidisciplinary approach in the management of abdominal or mediastinal mass.

BACKGROUND: Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a useful tool for the diagnosis of suspected abdominal or mediastinal neoplastic lesions. AIM: To evaluate the impact of EUS-FNA and multidisciplinary approach on the diagnostic work-up and therapeutic management of patients with abdominal or mediastinal neoplastic lesions. PATIENTS AND METHODS: One hundred and twenty patients (69 men, median age 65 years) with a suspected abdominal or mediastinal neoplastic mass at computed tomography or MRI underwent EUS-FNA. All EUS-FNA findings and clinical data were evaluated by a multidisciplinary team (oncologists, surgeons, and gastroenterologists). EUS-FNA findings were compared with the final diagnosis made by histological evaluation of the surgical specimen or clinical outcome at follow-up. RESULTS: A correct diagnosis was obtained by EUS-FNA in 96/120 patients (80%), indicating benignancy of the lesion in 21 (18%) cases and confirming malignancy in 75 (62%). On the basis of EUS-FNA findings, chemotherapy was tailored in 57/75 (76%) patients with malignancy whereas the surgical strategy was changed in 21/120 (18%) of patients. Overall, the diagnostic accuracy of EUS-FNA was 85%. A multidisciplinary team approach enabled a correct diagnosis in patients in whom EUS-FNA was nondiagnostic and to identify five cases with false-negative EUS-FNA findings. CONCLUSION: EUS-FNA has a relevant impact on the management of suspected abdominal or mediastinal neoplastic lesions. A multidisciplinary team approach enables to overcome the EUS-FNA methodological limitations. The combination of EUS-FNA and multidisciplinary team approach could help to diagnose and tailor therapeutic options in such patients.

A sonographic lesion index for Crohn's disease helps monitor changes in transmural bowel damage during therapy.

BACKGROUND & AIMS: Therapeutic antibodies against tumor necrosis factor α (anti-TNF) are effective in patients with Crohn's disease (CD). Mucosal healing is a surrogate marker of efficacy, but little is known about the effects of anti-TNF agents on structural damage in the intestine. Small-intestine contrast ultrasonography (SICUS) is a valuable tool for assessing CD lesions. A new sonographic quantitative index (the sonographic lesion index for CD [SLIC]) was developed to quantify changes in CD lesions detected by SICUS. We explored whether the SLIC can be used to monitor transmural bowel damage in CD patients during anti-TNF therapy. METHODS: We performed a prospective study of 29 patients with ileal or ileocolonic CD treated with anti-TNF agents; patients underwent SICUS before and after scheduled induction and maintenance therapy. To determine whether changes that can be detected by SICUS occur independently of anti-TNF therapy, 7 patients with ileal CD treated with mesalamine were enrolled as controls. A clinical response was defined as steroid-free remission, with CD activity index scores less than 150. RESULTS: We observed significant improvements in SLIC scores and subscores after induction and maintenance therapy with anti-TNFs, compared with before therapy. SLIC scores and subscores and index classes were improved significantly in patients with vs without clinical responses. Controls had no improvements in terms of CD activity index or SLIC scores, or index classes. CONCLUSIONS: Sonographic assessment using the quantitative index SLIC can be used to monitor changes in transmural bowel damage during anti-TNF therapy for CD.