Focus on Achalasia in the Omics Era.

Achalasia is a rare and complex esophageal disease of unknown etiology characterized by difficulty in swallowing due to the lack of opening of the lower esophageal sphincter and the absence of esophageal peristalsis. Recent advancements in technology for analyzing DNA, RNA and biomolecules in high-throughput techniques are offering new opportunities to better understand the etiology and the pathogenetic mechanisms underlying achalasia. Through this narrative review of the scientific literature, we aim to provide a comprehensive assessment of the state-of-the-art knowledge on omics of achalasia, with particular attention to those considered relevant to the pathogenesis of the disease. The notion and importance of the multi-omics approach, its limitations and future directions are also introduced, and it is highlighted how the integration of single omics data will lead to new insights into the development of achalasia and offer clinical tools which will allow early diagnosis and better patient management.

Artificial intelligence: A new tool in the pathologist's armamentarium for the diagnosis of IBD.

Inflammatory bowel diseases (IBD) are classified into two entities, namely Crohn's disease (CD) and ulcerative colitis (UC), which differ in disease trajectories, genetics, epidemiological, clinical, endoscopic, and histopathological aspects. As no single golden standard modality for diagnosing IBD exists, the differential diagnosis among UC, CD, and non-IBD involves a multidisciplinary approach, considering professional groups that include gastroenterologists, endoscopists, radiologists, and pathologists. In this context, histological examination of endoscopic or surgical specimens plays a fundamental role. Nevertheless, in differentiating IBD from non-IBD colitis, the histopathological evaluation of the morphological lesions is limited by sampling and subjective human judgment, leading to potential diagnostic discrepancies. To overcome these limitations, artificial intelligence (AI) techniques are emerging to enable automated analysis of medical images with advantages in accuracy, precision, and speed of investigation, increasing interest in the histological analysis of gastrointestinal inflammation. This review aims to provide an overview of the most recent knowledge and advances in AI methods, summarizing its applications in the histopathological analysis of endoscopic biopsies from IBD patients, and discussing its strengths and limitations in daily clinical practice.

Inflammatory bowel disease genomics, transcriptomics, proteomics and metagenomics meet artificial intelligence.

Various extrinsic and intrinsic factors such as drug exposures, antibiotic treatments, smoking, lifestyle, genetics, immune responses, and the gut microbiome characterize ulcerative colitis and Crohn's disease, collectively called inflammatory bowel disease (IBD). All these factors contribute to the complexity and heterogeneity of the disease etiology and pathogenesis leading to major challenges for the scientific community in improving management, medical treatments, genetic risk, and exposome impact. Understanding the interaction(s) among these factors and their effects on the immune system in IBD patients has prompted advances in multi-omics research, the development of new tools as part of system biology, and more recently, artificial intelligence (AI) approaches. These innovative approaches, supported by the availability of big data and large volumes of digital medical datasets, hold promise in better understanding the natural histories, predictors of disease development, severity, complications and treatment outcomes in complex diseases, providing decision support to doctors, and promising to bring us closer to the realization of the "precision medicine" paradigm. This review aims to provide an overview of current IBD omics based on both individual (genomics, transcriptomics, proteomics, metagenomics) and multi-omics levels, highlighting how AI can facilitate the integration of heterogeneous data to summarize our current understanding of the disease and to identify current gaps in knowledge to inform upcoming research in this field.

Deciphering Microbial Composition in Patients with Inflammatory Bowel Disease: Implications for Therapeutic Response to Biologic Agents.

Growing evidence suggests that alterations in the gut microbiome impact the development of inflammatory bowel diseases (IBDs), including Crohn's disease (CD) and ulcerative colitis (UC). Although IBD often requires the use of immunosuppressant drugs and biologic therapies to facilitate clinical remission and mucosal healing, some patients do not benefit from these drugs, and the reasons for this remain poorly understood. Despite advancements, there is still a need to develop biomarkers to help predict prognosis and guide treatment decisions. The aim of this study was to investigate the gut microbiome of IBD patients using biologics to identify microbial signatures associated with responses, following standard accepted criteria. Microbiomes in 66 stool samples from 39 IBD patients, comprising 20 CD and 19 UC patients starting biologic therapies, and 29 samples from healthy controls (HCs) were prospectively analyzed via NGS and an ensemble of metagenomics analysis tools. At baseline, differences were observed in alpha and beta metrics among patients with CD, UC and HC, as well as between the CD and UC groups. The degree of dysbiosis was more pronounced in CD patients, and those with dysbiosis exhibited a limited response to biological drugs. Pairwise differential abundance analyses revealed an increasing trend in the abundance of an unannotated genus from the Clostridiales order, Gemmiger genus and an unannotated genus from the Rikenellaceae family, which were consistently identified in greater abundance in HC. The Clostridium genus was more abundant in CD patients. At baseline, a greater abundance of the Odoribacter and Ruminococcus genera was found in IBD patients who responded to biologics at 14 weeks, whereas a genus identified as SMB53 was more enriched at 52 weeks. The Collinsella genus showed a higher prevalence among non-responder IBD patients. Additionally, a greater abundance of an unclassified genus from the Barnesiellaceae family and one from Lachnospiraceae was observed in IBD patients responding to Vedolizumab at 14 weeks. Our analyses showed global microbial diversity, mainly in CD. This indicated the absence or depletion of key taxa responsible for producing short-chain fatty acids (SCFAs). We also identified an abundance of pathobiont microbes in IBD patients at baseline, particularly in non-responders to biologic therapies. Furthermore, specific bacteria-producing SCFAs were abundant in patients responding to biologics and in those responding to Vedolizumab.

Follow-up evaluation and management of anemia in inflammatory bowel disease: A study by the Italian Group for Inflammatory Bowel Diseases (IG-IBD).

BACKGROUND: The RIDART I study found a 13.6% prevalence of anemia in Italian patients with inflammatory bowel disease (IBD); most cases were due to iron-deficiency anemia (IDA). AIMS: To evaluate changes in hemoglobin concentration during a 24-week follow-up of anemic patients with IBD. METHODS: Follow-up laboratory and clinical data were obtained from RIDART I study patients with anemia. Factors affecting hemoglobin concentration, the impact of anemia on fatigue and quality of life (QoL), and its relationship with treatment, disease activity and disease complications were investigated. RESULTS: Hemoglobin was 108 g/L at baseline, increased to 121 g/L at follow-up week 12 (p < 0.001) and then stabilized until week 24, but most patients remained anemic, with IDA, throughout the study. Hemoglobin improvement was greater in patients receiving either oral or parenteral iron supplementation. Following hemoglobin normalization, anemia relapse rate during follow-up was 30%. Oral iron did not cause disease reactivation. Lower follow-up hemoglobin was associated with a higher probability of having active disease, clinical complications, increased fatigue and reduced QoL. CONCLUSIONS: In anemic patients with IBD, anemia represents a long-lasting problem, in most cases persisting for up to 24 weeks, with high relapse rate and a negative impact on fatigue and QoL.

Switching from VEDOlizumab intravenous to subcutaneous formulation in ulcerative colitis patients in clinical remission: The SVEDO Study, an IG-IBD study.

BACKGROUND: The administration of biological drugs in inflammatory bowel diseases (IBD) is increasingly moving from intravenous to subcutaneous formulations. AIMS: To evaluate the efficacy and safety of vedolizumab subcutaneous administration after switching from intravenous administration in ulcerative colitis (UC) patients in corticosteroid-free clinical remission. METHODS: An observational, multicentre, prospective study was conducted by the Italian Group for the study of IBD (IG-IBD). UC patients in clinical remission (pMAYO < 2) not receiving steroids for > 8 months before the switch, and with at least 6 months of follow-up were included. Switch from intravenous to subcutaneous vedolizumab was defined as successful in patients not experiencing a disease flare (pMAYO ≥ 2) or needing oral steroids or stopping subcutaneous vedolizumab during the 6 months of follow-up after the switch. RESULTS: Overall, 168 patients were included. The switch was a success in 134 patients (79.8%). Vedolizumab retention rate was 88.7% at month six. C-reactive protein and faecal calprotectin values did not change after the switch (p = 0.07 and p = 0.28, respectively). Ten of the 19 patients who stopped subcutaneous formulation switched back to intravenous formulation recapturing clinical remission in 80%. Side effects were observed in 22 patients (13.1%). CONCLUSION: Effectiveness of switching from intravenous to subcutaneous vedolizumab formulation in UC patients in steroid-free clinical remission is confirmed in a real-world setting.

Gut virome-colonising Orthohepadnavirus genus is associated with ulcerative colitis pathogenesis and induces intestinal inflammation in vivo.

OBJECTIVES: Ulcerative colitis (UC) is a chronic inflammatory disorder of unknown aetiology. Gut virome dysbiosis is fundamental in UC progression, although its role in the early phases of the disease is far from fully understood. Therefore, we sought to investigate the role of a virome-associated protein encoded by the Orthohepadnavirus genus, the hepatitis B virus X protein (HBx), in UC aetiopathogenesis. DESIGN: HBx positivity of UC patient-derived blood and gut mucosa was assessed by RT-PCR and Sanger sequencing and correlated with clinical characteristics by multivariate analysis. Transcriptomics was performed on HBx-overexpressing endoscopic biopsies from healthy donors.C57BL/6 mice underwent intramucosal injections of liposome-conjugated HBx-encoding plasmids or the control, with or without antibiotic treatment. Multidimensional flow cytometry analysis was performed on colonic samples from HBx-treated and control animals. Transepithelial electrical resistance measurement, proliferation assay, chromatin immunoprecipitation assay with sequencing and RNA-sequencing were performed on in vitro models of the gut barrier. HBx-silencing experiments were performed in vitro and in vivo. RESULTS: HBx was detected in about 45% of patients with UC and found to induce colonic inflammation in mice, while its silencing reverted the colitis phenotype in vivo. HBx acted as a transcriptional regulator in epithelial cells, provoking barrier leakage and altering both innate and adaptive mucosal immunity ex vivo and in vivo. CONCLUSION: This study described HBx as a contributor to the UC pathogenesis and provides a new perspective on the virome as a target for tailored treatments.

Prevalence, Pathogenesis and Management of Anemia in Inflammatory Bowel Disease: An IG-IBD Multicenter, Prospective, and Observational Study.

BACKGROUND: Anemia is a common extraintestinal manifestation of inflammatory bowel disease (IBD), with a 6% to 74% prevalence and a negative impact on patient survival and quality of life, although the prevalence is apparently declining due to improved disease treatment. We aimed to investigate the prevalence, pathogenesis, and clinical correlates of anemia in Italian patients with IBD. METHODS: A multicenter, prospective, observational study, involving 28 Italian gastroenterology centers, was conducted to investigate the epidemiology and consequences of IBD-associated anemia. Clinical and laboratory data of anemic patients were obtained at study enrolment. RESULTS: Anemia was diagnosed in 737 of 5416 adult IBD outpatients (prevalence 13.6%); females were more commonly affected than males (odds ratio, 1.5; 95% confidence interval [CI], 1.2-1.7) and had more severe anemia. In the majority of cases, anemia was due to iron deficiency (62.5% of cases; 95% CI, 58.3%-66.6%), either isolated or in association with inflammation and/or vitamin deficiencies; anemia of inflammation accounted for only 8.3% of cases. More severe anemia was associated with increasing fatigue and worse quality of life. Only 68.9% of anemic patients with iron deficiency (95% CI, 63.4%-73.8%) and 34.6% of those with vitamin deficiencies (95% CI, 26.2%-44.2%) were properly treated with supplementation therapy. CONCLUSIONS: In Italy, the prevalence of IBD-associated anemia is lower than previously reported. Anemia of IBD is most commonly due to iron deficiency and contributes to fatigue and poor quality of life, but remains untreated in a large proportion of patients with iron and/or vitamin deficiencies. This study is registered at clinicaltrials.gov as NCT02872376.

The prevalence of inflammatory bowel disease­associated anemia is 13.6%. The prevalence is higher among females younger than 50. Anemia is usually due to iron deficiency and adversely affects fatigue and quality of life. Many patients with iron or vitamin deficiency (31% and 65%, respectively) remain untreated.

Clinic, Endoscopic and Histological Features in Patients Treated with ICI Developing GI Toxicity: Some News and Reappraisal from a Mono-Institutional Experience.

Background: Immune checkpoint inhibitors (ICIs) have widened the therapeutic scenario of different solid tumors over the last ten years. Gastrointestinal (GI) adverse events (AEs), such as diarrhea and colitis, occur in up to 50% of patients treated with ICIs. Materials and methods: We conducted a single-center retrospective analysis in patients with solid tumors treated with ICIs in a 6-year period, from 2015 to 2021, developing GI AEs, for which an endoscopic analysis was performed, with available histological specimens or surgery. Results: Twenty-one patients developed GI AEs under ICIs. The median time from the start of ICIs to the onset of GI AEs was 5 months. Diarrhea was the most frequent symptom (57.2%), upper GI symptoms presented in four patients (19%), while three patients (14.3%) had no symptoms and were diagnosed occasionally. Two patients underwent surgical resection for acute abdomen. Histological findings observed in endoscopic sampling were eosinophilic-pattern gastro-enterocolitis, apoptotic damage, IBD-like features, and ischemic-like changes. Histological damage was also documented in patients with unremarkable endoscopy. Conclusions: Under ICI therapy, GI toxicity is an expected event. Since GIAEs can mimic a broad range of primary GI diseases, a multidisciplinary approach is advocated with upper and lower GI mucosal sampling to remodel therapy and avoid complications.

Pattern-based Histologic Approach in Very Early Onset IBD: Main Features and Differential Diagnosis.

Very early onset inflammatory bowel disease (VEO-IBD) is a clinical umbrella classification composed of IBD-like diseases encompassing both classic IBD (Crohn's disease and ulcerative colitis) and monogenic disorder, both arising before 6 years of age. VEO-IBD patients present significant clinical differences from IBD occurring in older children and in adults, including more severe disease, often unresponsive to conventional IBD therapy and a greater proportion of cases featuring an underlying genetic alteration. Histologic findings of gastrointestinal biopsies can show an IBD-like pattern (both Crohn's disease-like and ulcerative colitis-like pattern), an apoptotic-like and enterocolitis-like pattern. Findings of specific morphologic alterations, such as villous blunting, apoptosis, dense eosinophilic infiltrates, lack of plasma cells and severe glandular atrophy, can suggest a monogenic disorder. Moreover, individuals with monogenic disorders may develop significant problems such as primary immunodeficiency, impacting treatment options. Finally, IBD histology in childhood can differ from that in older patients and adults. This complexity makes a differential diagnosis between IBD and other pediatric diseases involving the gastrointestinal tract difficult, especially considering that histologic features can be similar between different diseases. Without an appropriate diagnosis, the clinical course of VEO-IBD has greater potential for escalated treatment regimens involving extensive surgery and more intensive medical therapies rather than specific therapy directed toward the underlying defect. For these reasons, a pattern-based histologic approach correlated with clinical and laboratory findings with a multidisciplinary approach is fundamental to reach a correct diagnosis in an adequate clinical context.

Germline Alterations in Patients With IBD-associated Colorectal Cancer.

BACKGROUND: Patients with inflammatory bowel diseases (IBD), both ulcerative colitis (UC) and Crohn's disease (CD), are at risk of developing a colorectal cancer (CRC). No information is available on the contribution of patients' genetic background to CRC occurrence. This study investigates germline alterations in patients with IBD-associated CRC. METHODS: We profiled a panel of 39 genes potentially involved in cancer predisposition and searched for germline variants in IBD patients with CRC or high-grade dysplasia. RESULTS: After clinical exclusion of genetic cancer syndromes, 25 IBD patients (4 CD and 21 UC) with CRC or high-grade dysplasia were studied. After excluding variants with low likelihood of pathogenicity (classes 1 or 2 according the International Agency for Research on Cancer [IARC]), the panel identified pathogenic variants, likely pathogenic, or variants with unknown significance in 18 patients (72%). Six patients (24%) carried pathogenic or likely variants (IARC class 5 or 4). Of the identified variants, 4 encompassed the APC region, 3 the MLH1 gene, and the remaining ones the MSH2, MSH3, monoallelic MUTYH, EPCAM, BRCA1, CHEK2, POLD1, POLE, CDKN2A, and PDGFRA genes. Four patients carried at least 2 variants in different genes. Duration of IBD was significantly shorter in carriers of 4 or 5 IARC variants (7 years; range 0-21; P = .002) and in those with variants with unknown significance (12 years; range 0-22; P = .005) compared with patients without or with only benign variations (23.5 years; range 15-34). CONCLUSIONS: In silico analysis and sequence-based testing of germline DNA from IBD patients with CRC or high-grade dysplasia detected 24% of variants positioned in pathogenic classes. In patients with type 3, 4, and 5 variants, the onset of high-grade dysplasia or CRC was significantly earlier than in patients with benign or unidentified variants. The screening for these genes could identify IBD patients requiring a more intensive endoscopic surveillance for earlier detection of dysplastic changes.

Microbiome Analysis of Mucosal Ileoanal Pouch in Ulcerative Colitis Patients Revealed Impairment of the Pouches Immunometabolites.

The pathogenesis of ulcerative colitis (UC) is unknown, although genetic loci and altered gut microbiota have been implicated. Up to a third of patients with moderate to severe UC require proctocolectomy with ileal pouch ano-anastomosis (IPAA). We aimed to explore the mucosal microbiota of UC patients who underwent IPAA. METHODS: For microbiome analysis, mucosal specimens were collected from 34 IPAA individuals. Endoscopic and histological examinations of IPAA were normal in 21 cases, while pouchitis was in 13 patients. 19 specimens from the healthy control (10 from colonic and 9 from ileum) were also analyzed. Data were analyzed using an ensemble of software packages: QIIME2, coda-lasso, clr-lasso, PICRUSt2, and ALDEx2. RESULTS: IPAA specimens had significantly lower bacterial diversity as compared to normal. The microbial composition of the normal pouch was also decreased also when compared to pouchitis. Faecalibacterium prausnitzii, Gemmiger formicilis, Blautia obeum, Ruminococcus torques, Dorea formicigenerans, and an unknown species from Roseburia were the most uncommon in pouch/pouchitis, while an unknown species from Enterobacteriaceae was over-represented. Propionibacterium acnes and Enterobacteriaceae were the species most abundant in the pouchitis and in the normal pouch, respectively. Predicted metabolic pathways among the IPAA bacterial communities revealed an important role of immunometabolites such as SCFA, butyrate, and amino acids. CONCLUSIONS: Our findings showed specific bacterial signature hallmarks of dysbiosis and could represent bacterial biomarkers in IPAA patients useful to develop novel treatments in the future by modulating the gut microbiota through the administration of probiotic immunometabolites-producing bacterial strains and the addition of specific prebiotics and the faecal microbiota transplantation.

One-year effectiveness and safety of ustekinumab in ulcerative colitis: a multicenter real-world study from Italy.

BACKGROUND: Efficacy and safety of ustekinumab for the treatment of ulcerative colitis (UC) has been demonstrated in clinical trials, but few real-world data are available so far. The aim of this study was to assess effectiveness and safety of ustekinumab in a cohort of refractory UC patients. METHODS: Data of patients with moderate to severe UC treated with ustekinumab were retrospectively collected. Primary endpoint was steroid-free clinical remission at weeks 24 and 52 of therapy. Secondary endpoints were treatment response, endoscopic remission, treatment persistence at 12 months and safety. RESULTS: A total of 68 patients [males 63%; median (range) age 42 (16-72) years] were included. Almost all patients (97%) were biologics experienced. At weeks 24 and 52, 31% and 50% of patients achieved steroid-free clinical remission, 84% and 82% had clinical response, respectively. At the end of follow-up, there was a significant reduction of pMS from baseline (p < 0.001) and of steroid use (p < 0.001). At week 52, 22% of the available endoscopies (18/38) showed mucosal healing. The probability to persist in therapy at week 52 was 87%. Only one adverse event occurred. CONCLUSIONS: Data from our real-life cohort of refractory UC patients suggest satisfactory effectiveness and a good safety of ustekinumab.

Effectiveness and Safety of A Nutraceutical Formulation for the Treatment of Functional Dyspepsia in Primary Care.

BACKGROUND: Although FD may affect up to 10% of the general population, the therapy for FD is not standard. Recently, ginger-based food supplements have been proposed in order to restore FD symptoms. Our aim was to assess the efficacy of a new nutraceutical formulation containing extract of gingerol and thymus as a possible natural treatment in managing the symptoms of functional dyspepsia (FD). METHODS: We retrospectively analyzed the efficacy and safety profiles of a nutraceutical formulation containing Zingiber officinalis root extract and a standardized Thymus extract. It was administered as 1 ml/day twice a day for 90 days. Patients were assessed at baseline and after 1, 2 and 3 months of treatment, following a month of pharmacological washout by completing a questionnaire reporting the trend of the following symptoms: epigastric pain, epigastric heaviness, early satiety, belching, and regurgitation. Every symptom was assessed by a Visual Analogic Scale (VAS), ranging from 0= absence to 10= maximal severity. RESULTS: We enrolled 272 patients (99 males and 173 females; median IQR age 49.5, 36-64 yrs). Obesity (BMI>30) was present in 28 (12.5%) patients; smokers were 83 (30.5%); and comorbidities were present in 107 (39.3%) patients. Improvement of symptom scores during treatment and one month after its suspension was extremely significant (p<0.000). CONCLUSION: This large study found that nutraceutical formulation could be one of the tools for an empirical approach to treat patients with FD, especially when a non-conventional drug treatment is preferable for the patient and considered suitable by the physician.

Inverted colonic diverticulum (ICD): report of two cases and literature review of a not that unusual endoscopic challenge.

Inverted colonic diverticulum (ICD) is a rare intraluminal lesion occurring in about 0.7-1.7% of people, often endoscopically indistinguishable from polyps. Some unspecific endoscopic features may assist to distinguish polypoid ICD from true polyps. This differentiation bears relevance for the therapeutic approach, as colonic polyps require snare polypectomy, a practice which may be associated with colonic perforation in case of true ICD. The endoscopist, therefore, should be aware of the likelihood of detecting these lesions during colonoscopy. A close inspection and a gentle probing could assist in a correct diagnosis and avoid risky procedures such as biopsy or polypectomy. Rarely, a neoplasm arising over an ICD and its treatment has been described. We reported two cases, one of which with dysplasia, and their treatment, and reviewed all the ICD endoscopic cases so far reported in the literature, remarking the possibility of finding pedunculated ICDs or neoplasm arising over an ICD.

Interobserver agreement of the Paris and simplified classifications of superficial colonic lesions: a Western study.

Background and study aims The Paris classification of superficial colonic lesions has been widely adopted, but a simplified description that subgroups the shape into pedunculated, sessile/flat and depressed lesions has been proposed recently. The aim of this study was to evaluate the accuracy and inter-rater agreement among 13 Western endoscopists for the two classification systems. Methods Seventy video clips of superficial colonic lesions were classified according to the two classifications, and their size estimated. The interobserver agreement for each classification was assessed using both Cohen k and AC1 statistics. Accuracy was taken as the concordance between the standard morphology definition and that made by participants. Sensitivity analyses investigated agreement between trainees (T) and staff members (SM), simple or mixed lesions, distinct lesion phenotypes, and for laterally spreading tumors (LSTs). Results Overall, the interobserver agreement for the Paris classification was substantial (κ = 0.61; AC1 = 0.66), with 79.3 % accuracy. Between SM and T, the values were superimposable. For size estimation, the agreement was 0.48 by the κ-value, and 0.50 by AC1. For single or mixed lesions, κ-values were 0.60 and 0.43, respectively; corresponding AC1 values were 0.68 and 0.57. Evaluating the several different polyp subtypes separately, agreement differed significantly when analyzed by the k-statistics (0.08-0.12) or the AC1 statistics (0.59-0.71). Analyses of LSTs provided a κ-value of 0.50 and an AC1 score of 0.62, with 77.6 % accuracy. The simplified classification outperformed the Paris classification: κ = 0.68, AC1 = 0.82, accuracy = 91.6 %. Conclusions Agreement is often measured with Cohen's κ, but we documented higher levels of agreement when analyzed with the AC1 statistic. The level of agreement was substantial for the Paris classification, and almost perfect for the simplified system.

Accuracy and inter-observer agreement of the nice and kudo classifications of superficial colonic lesions: a comparative study.

PURPOSE: For superficial colonic lesions, the NICE and Kudo classifications are used in the in vivo prediction of histology and as guide to therapy. The NICE system derives information from unmagnified NBI endoscopic images. The Kudo one necessitates a magnification, but, as this tool is not commonly available, it is applied also to characterize unmagnified pictures to compare their diagnostic performances. METHODS: We conducted a prospective comparison of the NICE versus the Kudo classification for the differential diagnosis of colonic polyps taking histology as the gold standard. The inter-observer agreement for both classifications among 11 colonoscopists was also evaluated. Short unmagnified NBI videoclips of 64 colonic polyps were sent twice to the participants. In the first round, they classified the lesions according to the NICE classification; 4 months later, the same videos were assessed with the Kudo system. The diagnosis provided by the participants was grouped in non-neoplastic, non-invasive neoplasia, invasive neoplasia. RESULTS: Overall, the diagnostic accuracy was 82% (95%CI: 79-85) with the NICE system and 81% (95%CI: 78-84) with the Kudo one (ρ = 0.78). The accuracy of the NICE classification for non-neoplastic lesions was greater compared with the Kudo's (ρ = 0.03). Sensitivity sub-analyses revealed a higher ability of the NICE in distinguishing between neoplastic vs. non-neoplastic lesions (ρ = 0.01). The overall inter-rater agreement did not differ when the classifications were compared. CONCLUSION: The NICE and the Kudo classifications might be considered comparable. Our data could allow the use of the NBI Kudo classification even in those centers where magnification is not available.