Histological Remission in Ulcerative Colitis: Under the Microscope Is the Cure

Molecular Activity of Inflammation and Epithelial-Mesenchymal Transition in the Microenvironment of Ulcerative Colitis

Background/Aims

: The genetic expression in the active inflammatory regions is increased in ulcerative colitis (UC) with endoscopic activity. The aim of this study was to investigate the molecular activity of inflammation and tissue remodeling markers in endoscopically inflamed and uninflamed regions of UC.

Methods

: Patients with UC (n=47) and controls (n=20) were prospectively enrolled at the Seoul National University Bundang Hospital. Inflamed tissue was obtained at the most active lesion, and uninflamed tissue was collected from approximately 15 cm above the upper end of the active lesion via colonoscopic biopsies. The messenger RNA expression levels of transforming growth factor β (TGF-β), interleukin (IL)-1β, IL-6, IL-17A, E-cadherin, olfactomedin-4 (OLFM4), leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), vimentin, fibroblast-specific protein-1 (FSP1), and α-smooth muscle actin (SMA) were evaluated. Mucosal healing (MH) was defined according to a Mayo endoscopic score of 0, 1 or non-MH (Mayo endoscopic score of 2 or 3).

Results

: The messenger RNA expressions of TGF-β, IL-1β, OLFM4, FSP1, vimentin, and α-SMA were significantly higher, and that of E-cadherin was significantly lower in inflamed and uninflamed regions of patients with UC than those in controls. In the inflamed regions, patients in the non-MH group had significantly increased genetic expression of TGF-β, FSP1, vimentin, and α-SMA compared to patients in the MH group. Similarly, the non-MH group had significantly higher genetic expression of TGF-β, IL-1β, IL-6, vimentin, and α-SMA than the MH group in the uninflamed regions.

Conclusions

: Endoscopic activity in UC suggests inflammation and tissue remodeling of uninflamed regions similar to inflamed regions (ClinicalTrials.gov, NCT05653011).

Predictors of histologic remission in patients with biologic-naïve, moderate-to-severe ulcerative colitis treated with first-line biologic agents and small-molecule drugs: a single-center, retrospective cohort study

BACKGROUND/AIMS

The prevalence and incidence of ulcerative colitis (UC) in Korea is increasing. Each patient has a different disease course and treatment response. Recently, with the development of biologic agents, histological remission has become a treatment goal. In this study, we aimed to identify the predictors of histological remission after first-line biologic agent treatment in patients with biologic agent-naïve UC.

METHODS

We retrospectively analyzed the medical records of 92 patients who had been diagnosed with UC and treated with first-line biologic agent treatment at our center, between 2015 and 2022. The clinical characteristics, laboratory test results, and endoscopic and biopsy findings were analyzed. Histological remission was defined as the absence of cryptitis, crypt abscesses, and inflammatory cells on histology. Univariate and multivariate logistic regression analyses were performed to identify the predictors of histological remission after first-line treatment.

RESULTS

Of the total 92 patients, 25 (27.2%) achieved histological remission. Each cohort had a varied body mass index (BMI) distribution, with a statistically significant overweight ratio, as defined by the Asian-Pacific BMI category of 23-25 kg/m2, of 48.0% in the histological remission cohort (P= 0.026). A causal correlation between the overweight category and histological remission was confirmed (odds ratio, 3.883; 95% confidence interval, 1.141-13.212; P= 0.030).

CONCLUSIONS

We confirmed that the overweight category was a predictor of histological remission after first-line treatment with a biological agent. However, as BMI does not account for skeletal muscle mass, future studies are required to confirm the correlation between skeletal muscle mass and histological remission.

Deep mucosal healing in ulcerative colitis: how deep is better?

Ulcerative colitis (UC), characterized by its recurrent nature, imposes a significant disease burden and compromises the quality of life. Emerging evidence suggests that achieving clinical remission is not sufficient for long-term remission. In pursuit of a favorable prognosis, mucosal healing (MH) has been defined as the target of therapies in UC. This paradigm shift has given rise to the formulation of diverse endoscopic and histological scoring systems, providing distinct definitions for MH. Endoscopic remission (ER) has been widely employed in clinical practice, but it is susceptible to subjective factors related to endoscopists. And there's growing evidence that histological remission (HR) might be associated with a lower risk of disease flares, but the incorporation of HR as a routine therapeutic endpoint remains a debate. The integration of advanced technology has further enriched the definition of deep MH. Up to now, a universal standardized definition for deep MH in clinical practice is currently lacking. This review will focus on the definition of deep MH, from different dimensions, and analyze strengths and limitations, respectively. Subsequent multiple large-scale trials are needed to validate the concept of deep MH, offering valuable insights into potential benefits for UC patients.

Evaluation of the sensitivity and specificity of sigmoidoscopy in comparison to colonoscopy regarding the detection of intestinal inflammatory activity in the follow-up of patients with ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic disease characterized by periods of inflammatory activity and remission, which vary from the rectum to the proximal colon. Currently, mucosal healing is a long-term goal in the management of inflammatory bowel disease, with colonoscopy and sigmoidoscopy being the recommended tools for evaluation.

OBJECTIVE

To assess the effectiveness of both examinations in determining the presence of inflammatory activity in the follow-up of patients with UC.

METHODS

Retrospective observational study analyzing colonoscopies performed as part of the follow-up of UC patients between January 2021 and July 2023 by gastroenterologists from the Inflammatory Bowel Disease Program at the Clínica Universidad de los Andes. The study compared endoscopic and histological activity observed in the rectosigmoid region with that found in the rest of the colon. Sensitivity and specificity were determined using concordance and correlations tests.

RESULTS

A very good concordance and correlation were observed regarding endoscopic findings, with a Kappa index of 0.97 and a Spearman coefficient of 0.97. The Positive Predictive Value (PPV) of sigmoidoscopy for endoscopic activity was 1, and the Negative Predictive Value (NPV) was 0.96. In relation to histological activity, the concordance had a Kappa index of 0.93 and a Spearman coefficient of 0.93, with a PPV of sigmoidoscopy for histological activity being 1 and an NPV of 0.91.

CONCLUSION

This cohort suggests that sigmoidoscopy is a cost-effective option for evaluating mucosal healing in UC patients in symptomatic and biomarker remission. However, complete colonoscopy should be considered in cases of discrepancies with the clinical picture or in colorectal cancer surveillance.

Recent steroid use and the relapse risk in ulcerative colitis patients with endoscopic healing

BACKGROUND

Endoscopic healing (EH) is a therapeutic target in ulcerative colitis (UC). However, even patients who have achieved EH relapse frequently.

AIMS

To investigate the association between recent steroid use and relapse risk in UC patients with EH.

METHODS

This multi-centre cohort study included 1212 UC patients with confirmed EH (Mayo endoscopic subscore ≤1). We excluded patients with current systemic steroid use or history of advanced therapy. We divided patients into a recent steroid group (last systemic steroid use within 1 year; n = 59) and a non-recent or steroid-naïve group (n = 1153). We followed the patients for 2 years to evaluate relapse, defined as induction of systemic steroids or advanced therapy. We used logistic regression to estimate the odds ratio (OR) of relapse.

RESULTS

Relapse occurred in 28.8% of the recent steroid group and 5.6% of the non-recent/steroid-naïve group (multi-variable-adjusted OR 5.53 [95% CI 2.85-10.7]). The risk of relapse decreased with time since the last steroid use: 28.8% for less than 1 year after steroid therapy, 22.9% for 1 year, 16.0% for 2 years and 7.9% beyond 3 years, approaching 4.0% in steroid-naïve patients. (ptrend <0.001).

CONCLUSIONS

Even for patients with UC who achieved EH, the risk of relapse remains high following recent steroid therapy. Physicians need to consider the duration since last steroid use to stratify the relapse risk in UC patients with EH.

Residual Disease Burden Among European Patients With Inflammatory Bowel Disease: A Real-World Survey

BACKGROUND

Understanding disease burden is imperative for improving inflammatory bowel disease (IBD) management. This real-world survey investigated residual disease burden and treatment satisfaction among European patients with moderate-to-severe ulcerative colitis (UC) and Crohn's disease (CD).

METHODS

The Adelphi Real World IBD Disease Specific Programme was a multinational, cross-sectional survey with retrospective collection of patient- and physician-reported data on disease burden and management. Between October 2020 and March 2021, participating gastroenterologists recruited their next 7 (UC) and 8 (CD) eligible patients and reported demographics and clinical characteristics. Patients completed symptom, health-related quality of life (HRQoL), and treatment satisfaction questionnaires. Data were adjusted for confounding variables and compared between patients in remission (clinical remission, endoscopic remission, or both) and not in remission.

RESULTS

Overall, 1040 patients (UC, n = 502; CD, n = 538) were included. Although most patients were in remission (UC, 66.1%; CD, 69.5%), most still reported symptoms (UC, 63.7%; CD, 74.1%), including flatulence, fatigue/tiredness, and abdominal pain/distension. In UC, there were no significant differences in the likelihood of experiencing 7 of 23 symptoms between patients in remission and not in remission. In CD, there was no significant difference in 19 of 23 symptoms between patients in remission and not in remission. Several symptoms were significantly associated with reduced HRQoL. HRQoL was significantly better among patients in remission than not in remission.

CONCLUSIONS

Patients with IBD, both in remission and not in remission, experience residual symptoms that impair HRQoL. Comprehensive endpoints, incorporating HRQoL and patients' perspectives, and improved treatments are needed to address residual disease and patients' needs.

Monomeric C-Reactive Protein Potential Utilization in the Histological Assessment of Inflammatory Bowel Disease (IBD) Patients

Introduction Inflammatory bowel diseases (IBDs), including ulcerative colitis (UC) and Crohn's disease (CD), represent chronic progressive inflammatory gastrointestinal disorders, without a single reference standard for their diagnosis. The histological assessment gained an important role in accurately measuring disease activity, and mucosal healing (MH) was recently proposed to be an ideal treatment goal for patients with IBD because of its favorable prognosis, with a lower risk of recurrence or surgical treatment. This paper aims to add to the histological classical findings for IBD patients the identification of the monomeric form of the C-reactive protein (mCRP) as a supplementary marker that could be stained at the level of tissue samples and could be correlated with the pathogenic mechanism. Methods Two groups of 10 patients were each selected for the study, for both UC and CD, together with a control group. All samples collected through digestive endoscopy were analyzed by using H&E-stained slides, followed by immunohistochemical examination with antibodies to mCRP (M8C10), and markers of inflammatory activity through CD3, CD45(leukocyte common antigen (LCA)), CD138/syndecan-1 and CD68. Results For the CD study group, all histological elements identified with H&E and afterward stained with CD138, CD68, CD3, and CD45/LCA were correlated with the standards imposed by the European Crohn's and Colitis Organization (ECCO). For the group of patients with UC, histological images obtained with H&E and IHC stainings also confirmed the recommendation of ECCO. The main cells considered in the literature as histological markers for IBD are neutrophils, lymphocytes, and plasmocytes, stained in our study with CD45/LCA, CD3, and CD138. For all 20 cases of IBD (UC and CD), the staining with anti-Ab8C10 antibodies for mCRP was positive, while negative results were noticed within the control group. An mCRP protein visualized with anti-Ab8C10 antibodies presented an intracytoplasmatic localization in the neutrophils, plasma cells, lymphocytes, and macrophages from the lamina propria and glandular epithelium, without expression in endothelial cells. Conclusions Our study represents one of the first papers that identifies the localization of mCRP molecules within the intestinal mucosa of patients with IBD (both UC and CD) by using immunohistochemistry (IHC) staining. This finding opens a new perspective for considering mCRP as a marker correlated with histological disease activity and/or definition of histological remission in IBD.

Definitions of Histological Abnormalities in Inflammatory Bowel Disease: an ECCO Position Paper

Histological assessment of endoscopic biopsies in inflammatory bowel disease [IBD] plays an important role in clinical management, investigative studies, and clinical trials. Scoring schemes consisting of multiple histological items and offering considerable precision are widely available. However, definitions of histological abnormalities are often inconsistent. Furthermore, interobserver variability for their recognition and assessment may be high. The European Crohn's and Colitis Organisation [ECCO] formed an expert panel to explore definitions of histological abnormalities in IBD, with the aim of improving the quality of diagnosis and facilitating development of scoring schemes. The process confirmed that the current definitions often have no evidence base and vary between sources. Using available evidence and expert knowledge, the panel produced a series of ECCO consensus position statements on histological features in IBD.

Porcine Intestinal Mucosal Peptides Target Macrophage-Modulated Inflammation and Alleviate Intestinal Homeostasis in Dextrose Sodium Sulfate-Induced Colitis in Mice

Porcine intestinal mucosal proteins are novel animal proteins that contain large amounts of free amino acids and peptides. Although porcine intestinal mucosal proteins are widely used in animal nutrition, the peptide bioactivities of their enzymatic products are not yet fully understood. In the present study, we investigated the effect of porcine intestinal mucosal peptides (PIMP) on the RAW264.7 cell model of LPS-induced inflammation. The mRNA expression of inflammatory factors (interleukin 6, tumor necrosis factor-α, and interleukin-1β) and nitrous oxide levels were all measured by quantitative real-time PCR and cyclooxygenase-2 protein expression measured by Western blot. To investigate the modulating effect of PIMP and to establish a model of dextran sodium sulfate (DSS)-induced colitis in mice, we examined the effects of hematoxylin-eosin staining, myeloperoxidase levels, pro-inflammatory factor mRNA content, tight junction protein expression, and changes in intestinal flora. Nuclear factor κB pathway protein levels were also assessed by Western blot. PIMP has been shown in vitro to control inflammatory responses and prevent the activation of key associated signaling pathways. PIMP at doses of 100 and 400 mg/kg/day also alleviated intestinal inflammatory responses, reduced tissue damage caused by DSS, and improved intestinal barrier function. In addition, PIMP at 400 mg/kg/day successfully repaired the dysregulated gut microbiota and increased short-chain fatty acid levels. These findings suggest that PIMP may positively influence inflammatory responses and alleviate colitis. This study is the first to demonstrate the potential of PIMP as a functional food for the prevention and treatment of colitis.

Histologic assessments in ulcerative colitis: the evidence behind a new endpoint in clinical trials

INTRODUCTION

Treatment goals for ulcerative colitis (UC) are evolving from the achievement of clinical remission to more rigorous goals defined by endoscopic and histologic healing. Achievement of deeper remission targets aims to reduce the risk of colectomy, hospitalizations, and colorectal cancer.

AREAS COVERED

This review covers histologic assessments, histologic remission as a clinical trial endpoint, and the association between histologic disease activity and clinical outcomes. Future directions are also discussed, including the use of advanced imaging and artificial intelligence technologies, as well as potential future treatment targets beyond histologic remission.

EXPERT OPINION

Histologic assessments are used for their sensitivity in measuring mucosal inflammatory changes in UC. Due to correlation with disease activity, histologic assessments may support clinical decision-making regarding treatment decisions as such assessments can be associated with rates of clinical relapse, hospitalization, colectomy, and neoplasia. While histologic remission is limited by varying definitions and multiple histologic indices, work is ongoing to create a consensus on the use of histologic assessments in clinical trials. As research advances, aspirational targets beyond histologic remission, such as molecular healing and disease clearance, are being explored.

Evaluation of Disease Activity in Inflammatory Bowel Disease: Diagnostic Tools in the Assessment of Histological Healing

Inflammatory bowel disease (IBD) comprises two types of chronic intestinal disorders: Crohn's disease and ulcerative colitis. In long-standing ulcerative colitis disease activity, histological persistent inflammation has been linked to an increased risk of relapse, and long-term corticosteroid use, even when endoscopic remission is reached. In Crohn's disease, the discontinuous nature of lesions and transmural inflammation have limited the standardized histological assessment. The current evidence from research proposes that besides clinical and endoscopic healing, the achievement of histological healing constitutes an endpoint to assess disease activity and remission in IBD patients concerning better long-term disease outcomes. Histological alterations may persist even in the absence of endoscopic lesions. For these reasons, new advanced techniques promise to revolutionize the field of IBD by improving the endoscopic and histologic assessment, disease characterization, and ultimately patient care, with an established role in daily practice for objective assessment of lesions. This review outlines the importance of including microscopic evaluation in IBD, highlighting the clinical benefits of a deep state of disease remission using validated diagnostic methods and scoring systems for daily clinical practice.

Density of Biopsy Sampling Required to Ensure Accurate Histological Assessment of Inflammation in Active Ulcerative Colitis

BACKGROUND

Histological response to treatment is an important outcome in patients with ulcerative colitis (UC). The accuracy of biopsy-based measurements of inflammation may be limited by error imposed by natural microscopic heterogeneity on the scale of individual biopsies. We determined the magnitude of this error, its histological correlates, and the density of biopsy sampling within mucosal regions of interest required to meet specified benchmarks for accuracy.

METHODS

A total of 994 sequential 1-mm digital microscopic images (virtual biopsies) from consecutive colectomies from patients with clinically severe UC were scored by 2 pathologists. Agreement statistics for Geboes subscores and Nancy (NHI) and Robarts Histological Indices (RHI) between random samples from 1 to 10 biopsies and a reference mean score across a 2-cm region of mucosa were calculated using bootstrapping with 2500 iterations.

RESULTS

The agreement statistics improved across all indices as the biopsy density increased, with the largest proportional gains occurring with addition of the second and third biopsies. One biopsy achieved moderate to good agreement with 95% confidence for NHI and RHI corresponding to scale-specific errors of 0.40 (0.25-0.66) and 3.02 (2.08-5.36), respectively; and 3 biopsies achieved good agreement with 95% confidence corresponding to scale-specific errors of 0.22 (0.14-0.39) and 1.87 (1.19-3.25), respectively. Of the individual histological features, erosions and ulcers had the greatest impact on the agreement statistics.

CONCLUSIONS

In the setting of active colitis, up to 3 biopsy samples per region of interest may be required to overcome microscopic heterogeneity and ensure accurate histological grading.

Wheat Germ-Derived Peptide Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice

This study explores the protective properties and potential mechanisms of wheat-germ-derived peptide APEPEPAF (APE) against ulcerative colitis. Colitis mice induced by dextran sulfate sodium (DSS) were used as the animal model. The results showed that the APE peptide could alleviate colitis symptoms including weight loss, colon shortening, and histopathological changes. This peptide attenuated the generation of inflammatory cytokines by inhibiting the phosphorylation of protein kinase PKCζ (Thr410) and NF-κB transcriptional activity in DSS-induced mice, suggesting that APE ameliorates colitis inflammation by regulating the PKCζ/NF-κB signaling pathway. APE also preserved the barrier function of the colon by dose-dependently promoting the expression of tight junction proteins (claudin-1, zonula occluded-1, and occludin). In addition, APE significantly decreased the abundance of Bacteroides and increased the abundance of Dubosiella and Lachnospiraceae_UCG-006 to improve the intestinal flora imbalance in DSS-induced colitis mice. Therefore, wheat germ peptide APE can be used as a novel agent and dietary supplement to treat ulcerative colitis..

Correlation of mucosal healing endpoints with long-term clinical and patient-reported outcomes in ulcerative colitis

BACKGROUND

We evaluated the clinical relevance of achieving histologic endoscopic mucosal improvement (HEMI) and the more stringent target of histologic endoscopic mucosal remission (HEMR) in the phase 3 maintenance trial of upadacitinib for moderately to severely active ulcerative colitis.

METHODS

Clinical and patient-reported outcomes were assessed in patients with clinical response after 8- or 16-week upadacitinib induction who received 52-week upadacitinib maintenance treatment. Cross-sectional and predictive analyses evaluated the relationship between HEMR or HEMI at Week 8/16 and Week 52, respectively, and outcomes at Week 52. Adjusted odds ratios (aOR) were derived from logistic regressions for patients achieving HEMR or HEMI without HEMR versus those not achieving HEMI.

RESULTS

Cross-sectional analyses showed that patients with HEMR had greater odds of achieving all clinical and patient-reported outcomes at Week 52 than those not achieving HEMI. In predictive analyses, patients with HEMR at Week 8/16 had significantly greater odds of achieving clinical remission (aOR = 3.6, p = 0.001) and endoscopic remission (aOR = 3.9, p < 0.001) at Week 52 than patients not achieving HEMI and HEMR. For patients achieving HEMI without HEMR, these odds were lower: clinical remission (aOR = 3.2, p < 0.001) and endoscopic remission (aOR = 2.4, p = 0.010). The odds of achieving clinically meaningful improvements in most patient-reported outcomes were directionally similar between HEMI and HEMR, but not statistically different to patients not achieving HEMI. No hospitalizations or surgeries were observed in patients with HEMR at Week 52.

CONCLUSIONS

Achievement of HEMR or HEMI is clinically relevant with HEMR being associated with greater likelihood of improvement in long-term clinical and patient-reported outcomes. https://www.

CLINICALTRIALS

gov NCT02819635.

Quantitative Phase Imaging Using Digital Holographic Microscopy to Assess the Degree of Intestinal Inflammation in Patients with Ulcerative Colitis

Ulcerative colitis (UC) is characterized by chronic inflammation of the colorectum. Histological remission has emerged as a potential future treatment goal; however, the histopathological assessment of intestinal inflammation in UC remains challenging with a multitude of available scoring systems and the need for a pathologist with expertise in inflammatory bowel disease (IBD). In previous studies, quantitative phase imaging (QPI) including digital holographic microscopy (DHM) was successfully applied as an objective method for stain-free quantification of the degree of inflammation in tissue sections. Here, we evaluated the application of DHM for the quantitative assessment of histopathological inflammation in patients with UC. In our study, endoscopically obtained colonic and rectal mucosal biopsy samples from 21 patients with UC were analyzed by capturing DHM-based QPI images that were subsequently evaluated using the subepithelial refractive index (RI). The retrieved RI data were correlated with established histological scoring systems including the Nancy index (NI) as well as with endoscopic and clinical findings. As a primary endpoint, we found a significant correlation between the DHM-based retrieved RI and the NI (R² = 0.251, p < 0.001). Furthermore, RI values correlated with the Mayo endoscopic subscore (MES; R² = 0.176, p < 0.001). An area under the receiver operating characteristics (ROC) curve of 0.820 confirms the subepithelial RI as a reliable parameter to distinguish biopsies with histologically active UC from biopsies without evidence of active disease as determined by conventional histopathological examination. An RI higher than 1.3488 was found to be the most sensitive and specific cut-off value to identify histologically active UC (sensitivity of 84% and specificity of 72%). In conclusion, our data demonstrate DHM to be a reliable tool for the quantitative assessment of mucosal inflammation in patients with UC.

Study of the roles of caspase-3 and nuclear factor kappa B in myenteric neurons in a P2X7 receptor knockout mouse model of ulcerative colitis

BACKGROUND

The literature indicates that the enteric nervous system is affected in inflammatory bowel diseases (IBDs) and that the P2X7 receptor triggers neuronal death. However, the mechanism by which enteric neurons are lost in IBDs is unknown.

AIM

To study the role of the caspase-3 and nuclear factor kappa B (NF-κB) pathways in myenteric neurons in a P2X7 receptor knockout (KO) mouse model of IBDs.

METHODS

Forty male wild-type (WT) C57BL/6 and P2X7 receptor KO mice were euthanized 24 h or 4 d after colitis induction by 2,4,6-trinitrobenzene sulfonic acid (colitis group). Mice in the sham groups were injected with vehicle. The mice were divided into eight groups (n = 5): The WT sham 24 h and 4 d groups, the WT colitis 24 h and 4 d groups, the KO sham 24 h and 4 d groups, and the KO colitis 24 h and 4 d groups. The disease activity index (DAI) was analyzed, the distal colon was collected for immunohistochemistry analyses, and immunofluorescence was performed to identify neurons immunoreactive (ir) for calretinin, P2X7 receptor, cleaved caspase-3, total caspase-3, phospho-NF-κB, and total NF-κB. We analyzed the number of calretinin-ir and P2X7 receptor-ir neurons per ganglion, the neuronal profile area (µm²), and corrected total cell fluorescence (CTCF).

RESULTS

Cells double labeled for calretinin and P2X7 receptor, cleaved caspase-3, total caspase-3, phospho-NF-κB, or total NF-κB were observed in the WT colitis 24 h and 4 d groups. The number of calretinin-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (2.10 ± 0.13 vs 3.33 ± 0.17, P < 0.001; 2.92 ± 0.12 vs 3.70 ± 0.11, P < 0.05), but was not significantly different between the KO groups. The calretinin-ir neuronal profile area was increased in the WT colitis 24 h group compared to the WT sham 24 h group (312.60 ± 7.85 vs 278.41 ± 6.65, P < 0.05), and the nuclear profile area was decreased in the WT colitis 4 d group compared to the WT sham 4 d group (104.63 ± 2.49 vs 117.41 ± 1.14, P < 0.01). The number of P2X7 receptor-ir neurons per ganglion was decreased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (19.49 ± 0.35 vs 22.21 ± 0.18, P < 0.001; 20.35 ± 0.14 vs 22.75 ± 0.51, P < 0.001), and no P2X7 receptor-ir neurons were observed in the KO groups. Myenteric neurons showed ultrastructural changes in the WT colitis 24 h and 4 d groups and in the KO colitis 24 h group. The cleaved caspase-3 CTCF was increased in the WT colitis 24 h and 4 d groups compared to the WT sham 24 h and 4 d groups, respectively (485949 ± 14140 vs 371371 ± 16426, P < 0.001; 480381 ± 11336 vs 378365 ± 4053, P < 0.001), but was not significantly different between the KO groups. The total caspase-3 CTCF, phospho-NF-κB CTCF, and total NF-κB CTCF were not significantly different among the groups. The DAI was recovered in the KO groups. Furthermore, we demonstrated that the absence of the P2X7 receptor attenuated inflammatory infiltration, tissue damage, collagen deposition, and the decrease in the number of goblet cells in the distal colon.

CONCLUSION

Ulcerative colitis affects myenteric neurons in WT mice but has a weaker effect in P2X7 receptor KO mice, and neuronal death may be associated with P2X7 receptor-mediated caspase-3 activation. The P2X7 receptor can be a therapeutic target for IBDs.

Biopsies from ulcer edge yield higher histological activity scores than biopsies from non-ulcerated mucosa in active ulcerative colitis

BACKGROUND

The appropriate location for biopsy collection in ulcerative colitis is unknown.

OBJECTIVES

We aimed to determine the location for biopsy collection in the presence of ulcers which yields the highest histopathological score.

DESIGN AND METHODS

This prospective cross-sectional study enrolled patients with ulcerative colitis and ulcers in the colon. Biopsy specimens were obtained at the edge of the ulcer; at a distance of one open forceps (7-8 mm) from the ulcer edge; at a distance of three open forceps (21-24 mm) from the ulcer edge; further referred to as locations 1, 2 and 3 respectively. Histological activity was assessed using Robarts Histopathology Index and the Nancy Histological Index. Statistical analysis was performed using mixed effects models.

RESULTS

A total of 19 patients were included. Decreasing trends with distance from the ulcer edge ( P  < 0.0001) were observed. Biopsies procured from the edge of the ulcer (location 1) yielded a higher histopathological score compared to biopsies procured at locations 2 and 3 ( P  ≤ 0.001).

CONCLUSION

Biopsies from the ulcer edge yield higher histopathological scores than biopsies next to the ulcer. In clinical trials with histological endpoints, biopsies should be obtained from the ulcer edge (if ulcers are present) to reliably assess histological disease activity.

Comparative study between histochemical mucus volume, histopathological findings, and endocytoscopic scores in patients with ulcerative colitis

Ulcerative colitis (UC) causes a reduction in goblet cells. However, there have been few reports on the relationship between endoscopic and pathological findings and mucus volume. In this study, we quantitatively evaluated histochemical colonic mucus volume by fixing biopsied tissue sections taken from patients with UC in Carnoy's solution and compared it with endoscopic and pathological findings to determine whether there is a correlation between them. Observational study. A single-center, university hospital in Japan. Twenty-seven patients with UC (male/female, 16/11; mean age, 48.4 years; disease median duration, 9 years) were included in the study. The colonic mucosa of the most inflamed area and the surrounding less inflamed area were evaluated separately by local MES and endocytoscopic (EC) classification. Two biopsies were taken from each area; one was fixed with formalin for histopathological evaluation, and the other was fixed with Carnoy's solution for the quantitative evaluation of mucus via histochemical Periodic Acid Schiff and Alcian Blue staining. The relative mucus volume was significantly reduced in the local MES 1-3 groups, with worsening findings in EC-A/B/C and in groups with severe mucosal inflammation, crypt abscess, and severe reduction in goblet cells. The severity of inflammatory findings in UC by EC classification correlated with the relative mucus volume suggesting functional mucosal healing. We found a correlation between the colonic mucus volume and endoscopic and histopathological findings in patients with UC, and a stepwise correlation with disease severity, particularly in EC classification.

Artificial intelligence and inflammatory bowel disease: Where are we going?

Inflammatory bowel diseases, namely ulcerative colitis and Crohn's disease, are chronic and relapsing conditions that pose a growing burden on healthcare systems worldwide. Because of their complex and partly unknown etiology and pathogenesis, the management of ulcerative colitis and Crohn's disease can prove challenging not only from a clinical point of view but also for resource optimization. Artificial intelligence, an umbrella term that encompasses any cognitive function developed by machines for learning or problem solving, and its subsets machine learning and deep learning are becoming ever more essential tools with a plethora of applications in most medical specialties. In this regard gastroenterology is no exception, and due to the importance of endoscopy and imaging numerous clinical studies have been gradually highlighting the relevant role that artificial intelligence has in inflammatory bowel diseases as well. The aim of this review was to summarize the most recent evidence on the use of artificial intelligence in inflammatory bowel diseases in various contexts such as diagnosis, follow-up, treatment, prognosis, cancer surveillance, data collection, and analysis. Moreover, insights into the potential further developments in this field and their effects on future clinical practice were discussed.

Knowledge and attitudes towards the use of histological assessments in ulcerative colitis by gastroenterologists vs pathologists

BACKGROUND

Histological remission is increasingly accepted as a treatment endpoint in the management of ulcerative colitis (UC). However, the knowledge of histology guidelines and the attitudes towards their use in clinical practice by gastroenterologists and pathologists is unknown.

AIM

To evaluate the knowledge of histology guidelines and attitudes towards the use of histology in UC by gastroenterologists and pathologists.

METHODS

A prospective, cross-sectional nationwide survey of gastroenterologists and pathologists who analyse UC specimens was conducted. The survey consisted of 34 questions to assess gastroenterologists’ and pathologists’ knowledge (score out of 19) and attitudes towards histological assessment in UC. Survey questions were formulated using the European Crohn’s and Colitis position paper on histopathology and the British Society of Gastroenterology biopsy reporting guidelines. It included knowledge of histological assessment of disease activity and dysplasia, knowledge of histological scoring systems for ulcerative colitis, uptake of histology scoring systems in routine practice, attitudes towards the role of histological activity, and the use of histological activity in clinical scenarios.

RESULTS

Of 89 responders (77 gastroenterologists, 12 pathologists), there was almost universal acceptance that histological assessment should form part of UC evaluation [95% gastroenterologists, 92% pathologists]. However, gastroenterologists reported that 92% of their pathologists do not use a histological scoring system. Utilisation of a formal histological scoring system was preferred by 77% of gastroenterologists and 58% of pathologists. Both groups lacked awareness of the Geboes Score, Nancy Index and Robarts Histopathological Index scoring systems with 91%, 87%, and 92% of gastroenterologists respectively; and 83%, 83%, and 92% pathologists respectively, being uncertain of scoring systems’ remission definitions. Histology knowledge score was not significantly different between gastroenterologists and pathologists [9/19 (IQR: 8-11) vs 8/19 (IQR: 7-10), P = 0.54]. Higher knowledge scores were predicted by hospital attending gastroenterologists (P = 0.004), participation in inflammatory bowel disease (IBD) multidisciplinary teams (P = 0.009), and self-declared IBD sub-specialist (P = 0.03).

CONCLUSION

Histological remission is a recognised target for both gastroenterologists and pathologists. Despite this, knowledge of histological scoring systems and their utilisation is poor.

Intestinal Ultrasound Is Accurate to Determine Endoscopic Response and Remission in Patients With Moderate to Severe Ulcerative Colitis: A Longitudinal Prospective Cohort Study

BACKGROUND & AIMS

Intestinal ultrasound (IUS) is noninvasive, cost-effective, and accurate to determine disease activity in ulcerative colitis (UC). In this study, we prospectively evaluated IUS for treatment response in a longitudinal cohort by using endoscopy and histology as gold standards.

METHODS

Consecutive patients with moderate to severe UC (endoscopic Mayo score [EMS] ≥2) starting tofacitinib treatment were included. Patients were evaluated at baseline and after 8 weeks of tofacitinib induction by means of clinical, biochemical, endoscopic (EMS and UC endoscopic index for severity), histologic (Robarts Histopathologic Index) and IUS assessments. Readers of IUS, endoscopy, and histology were blinded for all other outcomes. The primary outcome was difference in bowel wall thickness (BWT) for endoscopic improvement vs no endoscopic improvement. Endoscopic remission was defined as EMS = 0, improvement as EMS ≤1, and response as a decrease of EMS ≥1.

RESULTS

Thirty patients were included, with 27 patients completing follow-up. BWT correlated with EMS (ρ = 0.68, P < .0001), UC endoscopic index for severity (ρ = 0.73, P < .0001) and Robarts Histopathologic Index (ρ = 0.49, P = .002) at both time points. BWT in the sigmoid was lower in patients with endoscopic remission (1.4 mm vs 4.0 mm, P = .016), endoscopic improvement (1.8 mm vs 4.5 mm, P < .0001) and decrease in BWT was more pronounced in patients with endoscopic response (-58.1% vs -13.4%, P = .018). The most accurate cutoff values for BWT were 2.8 mm (area under the curve [AUC] 0.87) for endoscopic remission, 3.9 mm (AUC 0.92) for improvement, and decrease of 32% (AUC 0.87) for response. The submucosa was the most responsive wall layer.

CONCLUSION

IUS, importantly BWT as the single most important parameter, is highly accurate to detect treatment response when evaluated against endoscopic outcomes.

Histopathological assessment of the microscopic activity in inflammatory bowel diseases: What are we looking for?

Advances in diagnostics of inflammatory bowel diseases (IBD) and improved treatment strategies allowed the establishment of new therapeutic endpoints. Currently, it is desirable not only to cease clinical symptoms, but mainly to achieve endoscopic remission, a macroscopic normalization of the bowel mucosa. However, up to one-third of IBD patients in remission exhibit persisting microscopic activity of the disease. The evidence suggests a better predictive value of histology for the development of clinical complications such as clinical relapse, surgical intervention, need for therapy escalation, or development of colorectal cancer. The proper assessment of microscopic inflammatory activity thus became an important part of the overall histopathological evaluation of colonic biopsies and many histopathological scoring indices have been established. Nonetheless, a majority of them have not been validated and no scoring index became a part of the routine bioptic practice. This review summarizes a predictive value of microscopic disease activity assessment for the subsequent clinical course of IBD, describes the most commonly used scoring indices for Crohn's disease and ulcerative colitis, and comments on current limitations and unresolved issues.

(Re)Appraising Remission in Ulcerative Colitis

As the therapeutic targets in ulcerative colitis (UC) shift from control of symptoms to mucosal healing and prevention of disease complications like disability, colectomy, and cancer, the definition of remission has evolved. The current definition of clinical remission is variable and is determined by the clinical context in which it is being used. This results in skepticism and uncertainty about the true meaning of the term "clinical remission." In this review, the authors reexamine the definition of clinical remission and propose a novel approach to define remission in UC.

Robust Colonic Epithelial Regeneration and Amelioration of Colitis via FZD-Specific Activation of Wnt Signaling

BACKGROUND AND AIMS

Current management of inflammatory bowel disease leaves a clear unmet need to treat the severe epithelial damage. Modulation of Wnt signaling might present an opportunity to achieve histological remission and mucosal healing when treating IBD. Exogenous R-spondin, which amplifies Wnt signals by maintaining cell surface expression of Frizzled (Fzd) and low-density lipoprotein receptor-related protein receptors, not only helps repair intestine epithelial damage, but also induces hyperplasia of normal epithelium. Wnt signaling may also be modulated with the recently developed Wnt mimetics, recombinant antibody-based molecules mimicking endogenous Wnts.

METHODS

We first compared the epithelial healing effects of RSPO2 and a Wnt mimetic with broad Fzd specificity in an acute dextran sulfate sodium mouse colitis model. Guided by Fzd expression patterns in the colon epithelium, we also examined the effects of Wnt mimetics with subfamily Fzd specificities.

RESULTS

In the DSS model, Wnt mimetics repaired damaged colon epithelium and reduced disease activity and inflammation and had no apparent effect on uninjured tissue. We further identified that the FZD5/8 and LRP6 receptor-specific Wnt mimetic, SZN-1326-p, was associated with the robust repair effect. Through a range of approaches including single-cell transcriptome analyses, we demonstrated that SZN-1326-p directly impacted epithelial cells, driving transient expansion of stem and progenitor cells, promoting differentiation of epithelial cells, histologically restoring the damaged epithelium, and secondarily to epithelial repair, reducing inflammation.

CONCLUSIONS

It is feasible to design Wnt mimetics such as SZN-1326-p that impact damaged intestine epithelium specifically and restore its physiological functions, an approach that holds promise for treating epithelial damage in inflammatory bowel disease.

PICaSSO Histologic Remission Index (PHRI) in ulcerative colitis: development of a novel simplified histological score for monitoring mucosal healing and predicting clinical outcomes and its applicability in an artificial intelligence system

Histological remission is evolving as an important treatment target in UC. We aimed to develop a simple histological index, aligned to endoscopy, correlated with clinical outcomes, and suited to apply to an artificial intelligence (AI) system to evaluate inflammatory activity.

METHODS

Using a set of 614 biopsies from 307 patients with UC enrolled into a prospective multicentre study, we developed the Paddington International virtual ChromoendoScopy ScOre (PICaSSO) Histologic Remission Index (PHRI). Agreement with multiple other histological indices and validation for inter-reader reproducibility were assessed. Finally, to implement PHRI into a computer-aided diagnosis system, we trained and tested a novel deep learning strategy based on a CNN architecture to detect neutrophils, calculate PHRI and identify active from quiescent UC using a subset of 138 biopsies.

RESULTS

PHRI is strongly correlated with endoscopic scores (Mayo Endoscopic Score and UC Endoscopic Index of Severity and PICaSSO) and with clinical outcomes (hospitalisation, colectomy and initiation or changes in medical therapy due to UC flare-up). A PHRI score of 1 could accurately stratify patients' risk of adverse outcomes (hospitalisation, colectomy and treatment optimisation due to flare-up) within 12 months. Our inter-reader agreement was high (intraclass correlation 0.84). Our preliminary AI algorithm differentiated active from quiescent UC with 78% sensitivity, 91.7% specificity and 86% accuracy.

CONCLUSIONS

PHRI is a simple histological index in UC, and it exhibits the highest correlation with endoscopic activity and clinical outcomes. A PHRI-based AI system was accurate in predicting histological remission.

Early Change in Epithelial Neutrophilic Infiltrate Predicts Long-Term Response to Biologics in Ulcerative Colitis

BACKGROUND & AIMS

The prognostic value of histologic scores, grades, and individual histologic subcomponents, alone or in combination with endoscopy, for predicting endoscopic improvement (EI) and histoendoscopic mucosal improvement (HEMI) during maintenance therapy in ulcerative colitis remains uncertain.

METHODS

We performed a post hoc analysis of participants from the VARSITY trial (n = 734 with histology). Receiver operating characteristic and multivariate logistic regression analyses were performed to assess whether baseline and/or week 14 assessments for the Robarts Histopathology Index, Geboes score, individual histologic subcomponents, and baseline disease characteristics, including endoscopic severity and biomarkers, could predict the achievement of EI and HEMI at week 52.

RESULTS

Changes in epithelial neutrophil involvement from baseline to week 14 had the best performance for predicting week 52 EI (area under the curve, 0.83; 95 % confidence interval [CI], 0.74-0.91) and HEMI (area under the curve, 0.85; 95 % CI, 0.76-0.94). On multivariate analyses, improvement of neutrophils in the epithelium was the only histologic parameter associated with increased odds of week 52 EI (odds ratio, 3.63; 95 % CI, 1.45-9.08; P = .0059) and HEMI (odds ratio, 6.88; 95 % CI, 3.29-14.36; P < .0001). Patients with more than 50 % of crypts involved with neutrophils at week 14 were significantly less likely to achieve week 52 HEMI irrespective of week 14 Mayo endoscopic scores (week 14 Mayo endoscopic score of 2-3: 9.9 % vs 22.4 %; P = .001; week 14 Mayo endoscopic score of 0-1: 33 % vs 62.4 %; P = .044).

CONCLUSIONS

Our results on epithelial neutrophilic infiltrate after induction therapy as the only independent predictor for achievement of maintenance EI or HEMI helps clarify the clinical relevance of measuring histologic disease activity in ulcerative colitis. Epithelial neutrophilic infiltrate poses a means to stratify patients according to their likelihood of response to biologic treatment.

Baseline Histological Findings Do Not Predict the Risk of Subsequent Extension in Patients with Limited Ulcerative Colitis

BACKGROUND

Among patients with limited ulcerative colitis (UC), 30% ultimately extend to pancolitis and are at increased risk of adverse clinical outcomes. Risk of endoscopic extension has been found to correlate with clinical features such as early age of onset.

AIMS

We sought to determine whether histologic features correlate with disease extension.

METHODS

The study population consisted of 40 patients with UC from two large academic centers diagnosed between 2006 and 2017. Eligible cases had a diagnosis of endoscopically limited UC (Montreal E1 or E2) at baseline and ≥ 2 subsequent endoscopic examinations with biopsies. Severity of inflammation was scored using both the Mount Sinai Activity Index and Nancy Histological Index.

RESULTS

Patients were divided into two cohorts: those who progressed to pancolitis (Montreal E3) were defined as "Extenders" (n = 21), whereas "Non-extenders" (n = 19) were cases without progression in the follow-up period. The median follow-up time was 58.4 months. The histologic scores in the endoscopically involved mucosa of the index biopsies were not associated with subsequent extension of disease, overall. However, among extender cohort, the index histology scores correlated with biopsy scores at extension (r = 0.455, P = 0.044) and index severity was associated with a shorter time to extension (r =  - 0.611, P = 0.003). Furthermore, female patients had a shorter time to extension (P = 0.013).

CONCLUSIONS

Histological severity of limited UC is not an independent predictor of extension in UC. However, among patients who subsequently extend, severe inflammation at baseline correlates with shorter progression time and severe inflammation when extension occurs. Patients with limited UC but severe histologic inflammation may warrant more frequent endoscopic surveillance.

Multicentre derivation and validation of a colitis-associated colorectal cancer risk prediction web tool

OBJECTIVE

Patients with ulcerative colitis (UC) diagnosed with low-grade dysplasia (LGD) have increased risk of developing advanced neoplasia (AN: high-grade dysplasia or colorectal cancer). We aimed to develop and validate a predictor of AN risk in patients with UC with LGD and create a visual web tool to effectively communicate the risk.

DESIGN

In our retrospective multicentre validated cohort study, adult patients with UC with an index diagnosis of LGD, identified from four UK centres between 2001 and 2019, were followed until progression to AN. In the discovery cohort (n=246), a multivariate risk prediction model was derived from clinicopathological features using Cox regression. Validation used data from three external centres (n=198). The validated model was embedded in a web tool to calculate patient-specific risk.

RESULTS

Four clinicopathological variables were significantly associated with AN progression in the discovery cohort: endoscopically visible LGD >1 cm (HR 2.7; 95% CI 1.2 to 5.9), unresectable or incomplete endoscopic resection (HR 3.4; 95% CI 1.6 to 7.4), moderate/severe histological inflammation within 5 years of LGD diagnosis (HR 3.1; 95% CI 1.5 to 6.7) and multifocality (HR 2.9; 95% CI 1.3 to 6.2). In the validation cohort, this four-variable model accurately predicted future AN cases with overall calibration Observed/Expected=1.01 (95% CI 0.64 to 1.52), and achieved 100% specificity for the lowest risk group over 13 years of available follow-up.

CONCLUSION

Multicohort validation confirms that patients with large, unresected, multifocal LGD and recent moderate/severe inflammation are at highest risk of developing AN. Personalised risk prediction provided via the Ulcerative Colitis-Cancer Risk Estimator ( www.UC-CaRE.uk ) can support treatment decision-making.

Histological Scores in Patients with Inflammatory Bowel Diseases: The State of the Art

The histological assessment has been advocated as a detailed and accurate measure of disease activity in inflammatory bowel diseases (IBD). In ulcerative colitis (UC), histological activity has been demonstrated to be associated with higher rates of relapse, prolonged corticosteroid use and long-term complications, even when endoscopic remission is achieved. Therefore, histological healing may represent a potential treatment target. Several histological scores have been developed and are available today. The Robarts histopathology index (RHI) and the Nancy index (NI) are the only two recommended by the European Crohn’s and Colitis Organization (ECCO) for use in patients with UC. Conversely, in Crohn’s disease (CD), the discontinuous nature of lesions has limited standardized histological assessment. Most of the available histological scoring systems in CD are complex and not validated. The aim of this review is to comprehensively summarize the latest evidence regarding histological scoring systems in IBD. We guide the reader through understanding the importance of an accurate microscopic evaluation using validated scoring systems, highlighting the strengths and pitfalls of each score. The priorities of future research needs are also addressed.

Randomised clinical trial: a phase 1b study of GB004, an oral HIF-1α stabiliser, for treatment of ulcerative colitis

BACKGROUND

Epithelial barrier dysfunction contributes to a dysregulated intestinal immune response in ulcerative colitis (UC). GB004 is an orally administered, small molecule, gut-targeted stabiliser of hypoxia-inducible factor-1α, a transcription factor with protective roles at the epithelial layer of the inflamed gut.

AIMS

To evaluate safety, pharmacokinetics, pharmacodynamics and efficacy of GB004 in patients with active UC.

METHODS

This double-blind, placebo-controlled study randomised patients 2:1 to receive an oral solution of GB004 120 mg or placebo once daily for 28 days. Eligible patients had a Robarts Histopathology Index score ≥4 with neutrophils in the epithelium, total Mayo Clinic score 3-12, Mayo Clinic endoscopic subscore ≥1, and blood in the stool, despite treatment with 5-aminosalicylates, corticosteroids or immunosuppressants.

RESULTS

Thirty-four patients were randomised. GB004 120 mg for 28 days was generally well-tolerated. Adverse events occurred in 27.3% (3/11) and 39.1% (9/23) of patients in the placebo and GB004 groups respectively. Nausea and dysgeusia were most commonly reported in the GB004 group (0% for placebo and 21.7% [5/23] and 13.0% [3/23] respectively for GB004). There were no treatment-related serious adverse events or deaths. GB004 exhibited minimal accumulation, with higher colonic concentrations relative to plasma. Exploratory pharmacodynamic and efficacy analyses demonstrated GB004 target engagement and numerically higher proportions of patients achieving improvement in multiple measures of disease activity, respectively, at day 28 for GB004 compared to placebo.

CONCLUSION

Results from this phase 1b trial support evaluation of the full therapeutic potential of GB004 for the treatment of UC. A phase 2 study (NCT04556383) is ongoing. Clinicaltrials.gov NCT03860896.

Combined Histo-endoscopic Remission but not Endoscopic Healing Alone in Ulcerative Colitis is Associated with a Mucosal Transcriptional Profile Resembling Healthy Mucosa

BACKGROUND AND AIMS

A composite endpoint of histological and endoscopic remission is proposed to be the most complete measure of mucosal healing in ulcerative colitis [UC]. We aim to establish the prognosis, and transcriptional and microbial features of histo-endoscopic remission and activity.

METHODS

A cross-sectional endoscopic rectosigmoid colon sample collection from UC patients and healthy controls [HC] was performed for histopathology and host genome-wide RNA-sequencing. Histo-endoscopic remission and histo-endoscopic activity were defined as Mayo endoscopic subscore [MES] 0-1 with and without histological activity, respectively. UC relapse, defined as symptomatic and endoscopic worsening, was retrospectively recorded for survival analysis. Unsupervised and differential gene expression analyses were performed, and the interaction between transcriptomics and mucosal gut microbiota was analysed based on the 16S rRNA gene sequencing profile.

RESULTS

UC patients with histo-endoscopic remission showed a significantly lower risk of relapse compared to histo-endoscopic activity. Unsupervised analysis of the transcriptomic profile showed that histo-endoscopic remission and histo-endoscopic activity samples clustered with HC and MES 2-3 samples, respectively. A total of 452 host genes enriched for humoral immune response, antimicrobial defence, chemokine and TH17 signalling pathway were upregulated in histo-endoscopic activity compared to histo-endoscopic remission. A set of host genes with antimicrobial properties showed significant associations with mucosal microbiota.

CONCLUSIONS

The rectosigmoid mucosa transcriptional profile of UC patients in histo-endoscopic remission resembles that of HC mucosa and confers a lower risk of relapse. These data support that the combination of histo-endoscopic remission could be the most appropriate definition of mucosal healing in UC.

Sampling and Reporting of Inflammatory Bowel Disease

Pathologists have an important and expanding role in the diagnosis and management of inflammatory bowel disease. This role includes the initial diagnosis of the disease, assessment of the response to treatment and the identification of short-term complications such as cytomegalovirus infection and long-term complications such as dysplasia. Furthermore, the assessment of resection specimens for complication of disease is important to determining the risk of subsequent disease or inflammation within an ileal pouch. Adequate sampling of the disease at endoscopy and from the surgical resection specimen is vital to determining the ultimate information that can be provided by the pathologist. This sampling is determined by the clinical scenario. Similarly, a standardized approach to reporting and synthesizing the histologic findings will improve patient management. This is best exemplified by the increasing interest in histologic activity indices, such as the Nancy index in ulcerative colitis, and in the standardized reporting for inflammatory bowel disease dysplasia recommended by the SCENIC international consensus.

Measuring Histologic Activity in Inflammatory Bowel Disease: Why and How

Histology is used to confirm the diagnosis of inflammatory bowel disease, exclude superimposed infections, and to evaluate for dysplasia. Histology has rarely been used to measure disease activity and guide therapy despite evidence that histologic measurements have value in predicting important clinical outcomes. More recently, there have been numerous studies supporting a role for histologic disease activity measurements in predicting a variety of outcomes including relapse, hospitalizations, steroid use, and dysplasia. The histologic assessment was superior to endoscopic measurements in many of these studies. This review will summarize the recent literature regarding histologic disease activity measurements in ulcerative colitis and Crohn disease. A detailed description of histologic scoring systems will also be provided to provide pathologists with the necessary tools to accurately measure disease activity.

Polysaccharides from Sargassum fusiforme after UV/H2O2 degradation effectively ameliorate dextran sulfate sodium-induced colitis

In this study, degraded polysaccharides from Sargassum fusiforme (PSF-T2) were prepared by UV/H2O2 treatment for 2 h, and its effects on ameliorating dextran sulfate sodium-induced colitis were evaluated using a mouse model. Results showed that PSF-T2 relieved colitis symptoms, characterized by increasing the colon length and body weight, decreasing disease activity index and relieving colon damage. In addition, PSF-T2 decreased the secretion and expression of IL-1β, IL-6 and TNF-α, and increased the expression of MUC-2, ZO-1 and occludin. Besides, PSF-T2 promoted the production of short-chain fatty acids and modulated gut microbiota composition (increasing the abundance of Lactobacillaceae, Lachnospiraceae, Oscillospiraceae and Desulfovibrionaceae, and decreasing Bacteroidaceae and Erysipelotrichaceae). These results suggested that polysaccharides from Sargassum fusiforme after UV/H2O2 degradation could ameliorate colitis by decreasing inflammation, protecting the intestinal barrier and modulating gut microbiota. It can provide a theoretical basis for the preparation of bioactive polysaccharides by free radical degradation.

Treatment Targets in Ulcerative Colitis: Is It Time for All In, including Histology?

The main therapeutic goal of ulcerative colitis (UC) is to induce and maintain remission to prevent long-term disease progression. Treat-to-target strategies, first introduced by the STRIDE consensus and updated in 2021, have shifted focus from symptomatic control toward more stringent objective endpoints. Today, patient monitoring should be based on a combination of biomarkers and clinical scores, while patient-reported outcomes could be used as short-term targets in monitoring disease activity and therapeutic response. In addition, endoscopic healing was the preferred long-term goal in UC. A Mayo endoscopic score (MES) ≤ 1 can be recommended as a minimum target. However, recent evidence suggests that more stringent endoscopic goals (MES of 0) are associated with superior outcomes. Recently, emerging data support that histological remission (HR) is a superior prognostic factor to endoscopic healing in predicting long-term remission. Despite not yet being recommended as a target, HR may become an important potential therapeutic goal in UC. However, it remains questionable if histological healing should be used as a routine assessment in addition to clinical, biomarker, and endoscopic targets in all patients. Therefore, in this review, our aim was to discuss the current evidence for the different treatment targets and their value in everyday clinical practice.

The endoscopic diagnosis of mucosal healing and deep remission in inflammatory bowel disease

The therapeutic goal in inflammatory bowel disease (IBD) patients has shifted from controlling the clinical activity alone to managing other associated problems. The concept of mucosal healing (MH) and deep remission (DR) are advocated and regarded as new therapeutic goals in IBD. However, the definition of MH still remains controversial. It is unclear whether or not the histological structures or functional factors should be included in the definition of DR in addition to clinical remission and MH. The classifications of white-light imaging (e.g. Mayo endoscopic subscore, UCEIS, CD Endoscopic Index of Severity, simple Endoscopic Score-CD) have been proposed and are now widely used to assess the severity as well as the MH of inflammation in IBD. In ulcerative colitis, magnifying chromoendoscopy has been shown to be useful to assess the MH of inflammation while other types of image-enhanced endoscopy, such as narrow-band imaging, have not. Endocytoscopy and confocal laser endomicroscopy (CLE) are also applied to assess the activity in IBD. These endoscopic procedures can estimate MH with more precision through observing the details of superficial structures, such as crypt openings. In addition, CLE can partially assess the mucosal function by detecting fluorescence leakage. Molecular imaging can possibly detect the molecules associated with inflammation, intestinal regeneration and differentiation, and various functions including the intestinal barrier and mucus secretion. These novel procedures may improve the diagnosis strategy of DR through the assessment of DR-associated factors such as the histological structures and functional factors in the near future.

Application of Artificial Intelligence to Clinical Practice in Inflammatory Bowel Disease - What the Clinician Needs to Know

Artificial intelligence [AI] techniques are quickly spreading across medicine as an analytical method to tackle challenging clinical questions. What were previously thought of as highly complex data sources, such as images or free text, are now becoming manageable. Novel analytical methods merge the latest developments in information technology infrastructure with advances in computer science. Once primarily associated with Silicon Valley, AI techniques are now making their way into medicine, including in the field of inflammatory bowel diseases [IBD]. Understanding potential applications and limitations of these techniques can be difficult, in particular for busy clinicians. In this article, we explain the basic terminologies and provide a particular focus on the foundations behind state-of-the-art AI methodologies in both imaging and text. We explore the growing applications of AI in medicine, with a specific focus on IBD to inform the practising gastroenterologist and IBD specialist. Finally, we outline possible future uses of these technologies in daily clinical practice.

Artificial intelligence application in diagnostic gastrointestinal endoscopy - Deus ex machina?

The close relationship of medicine with technology and the particular interest in this symbiosis in recent years has led to the development of several computed artificial intelligence (AI) systems aimed at various areas of medicine. A number of studies have demonstrated that those systems allow accurate diagnoses with histological precision, thus facilitating decision-making by clinicians in real time. In the field of gastroenterology, AI has been applied in the diagnosis of pathologies of the entire digestive tract and their attached glands, and are increasingly accepted for the detection of colorectal polyps and confirming their histological classification. Studies have shown high accuracy, sensitivity, and specificity in relation to expert endoscopists, and mainly in relation to those with less experience. Other applications that are increasingly studied and with very promising results are the investigation of dysplasia in patients with Barrett's esophagus and the endoscopic and histological assessment of colon inflammation in patients with ulcerative colitis. In some cases AI is thus better than or at least equal to human abilities. However, additional studies are needed to reinforce the existing data, and mainly to determine the applicability of this technology in other indications. This review summarizes the state of the art of AI in gastroenterological pathology.

Novel trends with biologics in inflammatory bowel disease: sequential and combined approaches

Inflammatory bowel disease (IBD) management has changed dramatically over the past 20 years, after the introduction of targeted biological therapies. However, the impact of these new drugs in changing the natural history of disease is still under debate. Recent evidence seems to suggest that the extent of their efficacy might be, at least partially, dependent on the timing of their introduction and on the subsequent management strategy. In this complex landscape, the potential role for a more dynamic approach with treatments based on sequencing and combining targeted therapies has been explored only minimally so far. In this review, we aim to explore the potential biological rationale behind the use of sequential and combination therapies in IBD, to summarise the current knowledge on this topic and to propose a management algorithm that combines these notions.

Variability in the Distribution of Histological Disease Activity in the Colon of Patients with Ulcerative Colitis

BACKGROUND AND AIMS

Histological activity scores have been developed and validated. However, data on the distribution of histological inflammation within one segment in patients with ulcerative colitis [UC] are lacking. This impacts on the reliability of histological activity scores. The aim of this study was to assess the variability in histological activity within one endoscopic segment in patients with UC.

METHODS

Biopsies were taken in sequential patients with UC in three adjacent contiguous regions within a macroscopically homogeneous colonic segment. Biopsies were scored for Geboes score [GS], Robarts histological index [RHI] and Nancy histological index [NHI]. Variability was assessed by Kappa statistics for categorical outcomes and intraclass correlation coefficient [ICC] for continuous outcomes.

RESULTS

A total of 161 biopsy sets from 55 endoscopic segments of 21 patients were analysed. Endoscopically active disease was present in 45% of segments. The continuous histological scores showed excellent agreement between the different regions. The ICC for RHI in all segments was 0.974 (95% confidence interval [CI] 0.958-0.984; p < 0.0001) and 0.98 [95% CI: 0.968-0.988; p < 0.0001] for the numerically converted GS. The categorical NHI showed higher variability: κ = 0.574 [95% CI: 0.571-0.577; p < 0.0001]. In all segments the highest variability was seen in samples with NHI = 2. When dichotomizing based on histological remission, substantial agreement was seen for all scores, with κ > 0.734 for all cut-offs. The homogeneity in the distribution of histological disease activity was comparable between colonic segments.

CONCLUSION

The distribution of histological disease activity in UC follows a homogeneous pattern in different locations of one segment.

A Practical Guide for Faecal Calprotectin Measurement: Myths and Realities

BACKGROUND AND AIMS

Faecal calprotectin [FC] is a valid and non-invasive marker of mucosal inflammation. It is widely used both in clinical trials and in daily clinical practice for patients with inflammatory bowel diseases, but currently no accepted standardization for FC testing is available. Our primary aim here was to provide a clinician's guide containing all the practical information on FC measurement in order to avoid any confounding factors, to minimize intra- and inter-individual variability in dosage, and to ensure a better and adequate interpretation of the results.

METHODS

We conducted a detailed search of the scientific literature in the PubMed/MEDLINE, EMBASE and Cochrane databases up to January 2020 to find all relevant and available articles on pre-analytical and analytical phases of FC measurement.

RESULTS

FC testing is a multi-step procedure consisting of a pre-analytical phase aimed to collect and process the stool sample and a subsequent analytical phase of FC measurement. Several factors can influence test results determining false positives or false negatives. Importantly, this faecal marker is mostly used for patient follow-up and as a predictor of treatment response. For this reason, any altered data may affect the physicians' decisions, negatively impacting on patient management.

CONCLUSIONS

This review provides for the first time practical advice to minimize dosage variability, although further dedicated studies are needed to compare commercially available tests and identify the best tools for the most precise and accurate FC measurement.

Select animal models of colitis and their value in predicting clinical efficacy of biological therapies in ulcerative colitis

Introduction: Advancing new therapies from discovery to development usually requires proof-of-concept in animal models to justify the costs of continuing the program. While animal models are useful for understanding the mechanism of action (MOA) of a target, limitations of many published colitis models restrict their value to predict clinical efficacy.Areas covered: The authors focused their literature search on published studies of chronic animal models used to evaluate the pre-clinical efficacy of therapeutic molecules subsequently evaluated in clinical trials for UC. The UC therapies evaluated were anti-α4β7, anti-IL13, anti-IL12p40, and anti-IL23p19. The models of chronic colitis evaluating these molecules were: mdra1a-/-, chronic dextran sulfate sodium (DSS), chronic 2,4,6-trinitrobenzene sulfonic acid (TNBS), and the T cell transfer model.Expert opinion: While some models provide insight into target MOA in UC, none is consistently superior in predicting efficacy. Evaluation of multiple models, with varying mechanisms of colitis induction, is needed to understand potential drug efficacy. Additional models of greater complexity, reflecting the disease chronicity/heterogeneity seen in humans, are needed. Although helpful in prioritizing targets, animal models alone will likely not improve outcomes of UC clinical trials. Transformational changes to clinical efficacy will likely only occur when precision medicine approaches are employed.

Early microscopic findings in preclinical inflammatory bowel disease

BACKGROUND

The immune response involved in the pathogenesis of Inflammatory Bowel Disease (IBD) may be present years before the diagnosis, but the characteristics of the disease during the preclinical period have been scarcely investigated.

AIM

To describe the microscopic findings of preclinical IBD and its relationship with the natural history of the disease.

METHODS

Medical records from all patients with an incidental diagnosis of IBD during a screening colonoscopy were included in this multicentric and retrospective study. We assessed 15 histologic items in the biopsy samples at diagnosis, and the Geboes score was calculated in patients with Ulcerative Colitis (UC). The main outcome was the development of gastrointestinal symptoms during follow-up.

RESULTS

We included 110 patients (79 UC, 24 Crohn's Disease (CD) and 7 with unclassified disease). In UC the most common histologic findings were acute or chronic inflammatory infiltrate and crypt epithelial polymorphs, while in CD we observed acute or chronic neutrophilic infiltrate and epithelial irregularity. Granuloma were only observed in 4% of CD patients. Crypt distortion and the infiltration of neutrophils in the epithelium were associated with a higher risk of developing symptomatic disease.

CONCLUSIONS

Preclinical IBD shows specific microscopic findings and they are associated with the progression to symptomatic disease.

Relationship Between Combined Histologic and Endoscopic Endpoints and Efficacy of Ustekinumab Treatment in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Ustekinumab induces and maintains histologic improvement in patients with ulcerative colitis (UC). The clinical relevance of this endpoint alone, and in combination with endoscopic improvement, is unknown.

METHODS

Histologic disease activity was evaluated in 2630 colonic biopsy samples from patients with UC treated in the UNIFI phase 3 UC clinical studies of ustekinumab. We evaluated associations between histologic improvement (defined as the composite of neutrophil infiltration in less than 5% of crypts and no crypt destruction, erosions, ulcerations, or granulation tissue) and clinical endpoints at the end of induction (week 8 and 16) and maintenance (week 44) periods. We assessed the validity of a combined histologic and endoscopic (Mayo endoscopy subscore, 0 or 1) improvement endpoint, which we called histo-endoscopic mucosal healing (or histo-endoscopic mucosal improvement).

RESULTS

Histologic improvement was significantly (P < .0001) associated with clinical remission, lower mean disease activity scores, and greater improvement in disease activity at the end of induction and maintenance studies. Ustekinumab induced and maintained significantly higher rates of histologic improvement at induction week 8 and maintenance week 44 than placebo when more stringent definitions of histologic improvement were used. Histologic improvement and endoscopic improvement following induction were associated with 10% to 20% higher rates of histo-endoscopic mucosal healing, clinical remission, and corticosteroid-free remission at week 44 (all P < .05) in patients who received ustekinumab maintenance therapy. At week 44, 61% of patients (56/92) with histo-endoscopic mucosal healing after induction therapy achieved clinical remission, versus 39% of patients (9/23, P = .0983) and 34% of patients (24/71, P = .0009) with endoscopic or histologic improvement alone after induction, respectively.

CONCLUSION

Data from the UNIFI program of ustekinumab in patients with UC treated with ustekinumab indicated the achievement of histo-endoscopic mucosal healing after induction therapy is associated with lower disease activity at the end of maintenance therapy than either histologic or endoscopic improvement alone. ClinicalTrials.gov number: NCT02407236.

ECCO Position Paper: Harmonization of the Approach to Ulcerative Colitis Histopathology

Currently, the main targets of drug therapy for ulcerative colitis [UC] are endoscopic and clinical remission. However, there is active discussion about the additional advantages of including histological remission as a target. Accumulating evidence indicates that microscopic activity persists in endoscopically quiescent UC, that histological changes may lag behind clinical remission after treatment, and that absence of histological activity predicts lower rates of relapse, hospitalization, surgery and subsequent neoplasia. Obtaining useful information from mucosal biopsies in this setting depends on accurate and consistent evaluation of histological features. However, there is no standardization of biopsy procedures, histological sample processing technique or histological scoring systems, and there is no agreement on the definitions of histological remission, response or activity. Accordingly, a consensus expert panel convened by the European Crohn's and Colitis Organisation [ECCO] reviewed the literature and agreed a number of position statements regarding harmonization of UC histopathology. The objective was to provide evidence-based guidance for the standardization and harmonization of procedures, definitions and scoring systems for histology in UC, and to reach expert consensus where possible. We propose the absence of intraepithelial neutrophils, erosion and ulceration as a minimum requirement for the definition of histological remission. For randomized control trials we recommend the use of the Robarts histopathology index [RHI] or the Nancy index [NI]. For observational studies or in clinical practice we recommend the use of the NI. To predict the risk of future neoplasia in UC, cumulative histological scores over time are more useful than single scores.

Incremental Benefit of Achieving Endoscopic and Histologic Remission in Patients With Ulcerative Colitis: A Systematic Review and Meta-Analysis

BACKGROUND & AIMS

Clinical remission, defined by a composite of patient reported outcomes and Mayo endoscopy subscore (MES) 0 or 1 is a recommended treatment target in patients with ulcerative colitis (UC). We estimated whether incorporating more rigorous remission definitions, of endoscopic remission (MES 0) and histologic remission, affects risk of relapse.

METHODS

Through a systematic review, we identified cohort studies in adults with UC in clinical remission that reported a minimum 12-month risk of clinical relapse, based on MES (0 vs 1) and/or histologic disease activity, in patients with endoscopic remission. Using random effects meta-analysis, we calculated relative and absolute risk of clinical relapse in patients with UC achieving different treatment targets.

RESULTS

In a meta-analysis of 17 studies that included 2608 patients with UC in clinical remission, compared to patients achieving MES 1, patients achieving MES 0 had a 52% lower risk of clinical relapse (relative risk, 0.48; 95% CI, 0.37-0.62). The median 12-month risk of clinical relapse in patients with MES 1 was 28.7%; the estimated annual risk of clinical relapse in patients with MES 0 was 13.7% (95% CI, 10.6-17.9). In a meta-analysis of 10 studies in patients in endoscopic remission (MES 0), patients who achieved histologic remission had a 63% lower risk of clinical relapse vs patients with persistent histologic activity (relative risk, 0.37; 95% CI, 0.24-0.56). Estimated annual risk of clinical relapse in who achieved achieving histologic remission was 5.0% (95% CI, 3.3-7.7).

CONCLUSIONS

In a systematic review and meta-analysis of patients with UC in clinical remission, we observed that patients achieving more rigorous treatment endpoints (endoscopic and histologic remission) have a substantially lower risk of clinical relapse compared with patients achieving clinical remission.