Advanced endoscopic imaging for diagnosis of inflammatory bowel diseases: Present and future perspectives

Advanced Endoscopic Imaging for Assessing Mucosal Healing and Histologic Remission in Inflammatory Bowel Diseases

Recent advances in the field of endoscopy have found fertile ground for application in inflammatory bowel diseases (IBD). Mucosal healing is a primary goal of IBD therapy, and current evidence shows that histologic remission (HR) is an additional desirable outcome. However, with the use of standard endoscopy, a considerable number of patients with histologically active disease go unrecognized. This narrative article examines the role, current or potential, of each endoscopic technique, from standard white-light endoscopy to molecular imaging, in the assessment of mucosal healing and HR in IBD.

Crohn's disease and clinical management today: How it does?

Crohn's Disease (CD) is an Inflammatory Bowel Disease and is characterized by an immune-mediated nature. Its etiology results from the interaction between genetic, enviromental and microbial factors. Regarding pathophysiology, it involves high levels of interleukin (IL)-12, IL-17, and Th1 profile, along with loss of tolerance mechanisms, an increase in pro-inflammatory interleukins, beyond the possibility to affect any part of the gastrointestinal tract. Its symptoms include abdominal pain, chronic diarrhea, weight loss, anorexia, and fatigue, as well as blood in the stool or rectum. Additionally, conditions comprising musculoskeletal, cutaneous, ocular, hepatic, and hematological alterations may be associated with this scenario and extra-intestinal presentation, such as erythema nodosum, anterior uveitis, osteoporosis, and arthritis can also occur. Today, clinical history, exams as fecal calprotectin, ileocolonocopy, and capsule endoscopy can be performed in the diagnosis investigation, along with treatments to induce and maintain remission. In this sense, anti-inflammatory drugs, such as corticosteroids, immunomodulators, and biological agents, as well as surgery and non-pharmacological interventions plays a role in its therapy. The aim of this review is to bring more current evidence to clinical management of CD, as well as to briefly discuss aspects of its pathophysiology, surveillance, and associated disorders.

Predicting Histological Healing and Recurrence in Ulcerative Colitis by Assessing Mucosal Vascular Pattern Under Narrow-Band Imaging Endoscopy

This study investigated the predictive value of narrow-band imaging (NBI) endoscopic staging of different mucosal vascular patterns (MVPs) in patients with ulcerative colitis (UC) for histological healing or clinical recurrence of patients with UC. A total of 124 patients with UC in clinical remission attending the First Affiliated Hospital of Weifang Medical College were included in the study and underwent NBI colonoscopy. Inflammatory activity was assessed in the intestine using the Mayo endoscopic score (MES) and the MVP. Mucosal inflammation was histologically graded using the Nancy index (NI). The colons of 124 patients with UC were staged according to NBI endoscopic MVP staging criteria. The differences between NBI colonoscopy MVP typing and white light endoscopic MES in assessing histological healing (HH) were statistically significant (p < 0.001), and there was a moderate correlation between MES and the degree of HH (r = 0.471, p < 0.001). In addition, there was a significant correlation between the severity of mucosal activity determined by white light endoscopy (WLE) and MVP staging (r = 0.811, p < 0.001). The differences between NBI endoscopic MVP staging and white light endoscopic MES in assessing UC recurrence were statistically significant (p < 0.001). Spearman's correlation analysis showed a moderate correlation between NBI endoscopic MVP staging and clinical recurrence. NBI endoscopic MVP staging can predict HH and clinical recurrence status better than WLE.

HucMSC-Ex carrying miR-203a-3p.2 ameliorates colitis through the suppression of caspase11/4-induced macrophage pyroptosis

BACKGROUND

Inflammatory bowel disease (IBD) is a kind of chronic, idiopathic, and recurrent inflammation, associated with dysregulated intestinal mucosal immunity. Caspase (casp) 11/4-induced macrophage pyroptosis contributes to the development of inflammation, while human umbilical cord mesenchymal stem cell-secreted exosomes (hucMSC-Ex) play a reparative role in IBD.

OBJECTIVE

The present study focused on the treatment of IBD with hucMSC-Ex and its regulatory mechanism via the casp11/4 pathway.

METHODS

BALB/c mice were used to establish a dextran sulfate sodium (DSS)-induced colitis model, and hucMSC-Ex was administered intravenously to estimate its therapeutic effect. In vitro, RAW264.7 cells line, THP-1 cells line, and mouse peritoneal macrophages (MPMs) were stimulated with lipopolysaccharides (LPS) to activate an inflammatory environment of pyroptosis, followed by repairing with hucMSC-Ex. MicroRNA mimics and inhibitors were provided to verify the role of miR-203a-3p.2 from hucMSC-Ex in inflammation. The results were analyzed by Western blot, RT-qPCR、ELISA, and LDH secretion.

RESULTS

HucMSC-Ex inhibited the activation of casp11 and reduced the secretion of interleukin (IL)-1β, IL-6, and casp11, which relieved macrophage pyroptosis to alleviate murine colitis. A consistent outcome was revealed in the cell experiments, where hucMSC-Ex contributed to a decreased casp11/4 expression, and lactate dehydrogenase (LDH) release, as a marker of cell damage. Moreover, miR-203a-3p.2 from hucMSC-Ex functioned as an effective mediator in the interaction with casp4 in THP-1 macrophage pyroptosis.

CONCLUSION

HucMSC-Ex ameliorates colitis through the suppression of casp11/4-induced macrophage pyroptosis, and hucMSC-Ex carrying miR-203a-3p.2 inhibits casp4-induced macrophage pyroptosis in an inflammatory environment.

The classification of gastric antral vascular ectasia in cirrhotic patients by Versatile Intelligent Staining Technology

Background

Portal hypertensive gastropathy (PHG) and gastric antral vascular ectasia (GAVE) are two different pathologies that cause bleeding in cirrhotic patients. These two pathologies are still difficult to be distinguished by white light endoscopy (conventional), as they both appear as red spots in the gastric antral mucosa in the case of severe PHG. The aim of our study was to assess the efficacy of Versatile Intelligent Staining Technology (VIST) in comparison to histopathology in the diagnosis and classification of GAVE.

Methods

A cross-sectional study included 50 patients with liver cirrhosis recruited from Alexandria Main University Hospital. Patients with connective tissue diseases and chronic kidney disease were excluded. All patients were examined by both conventional white light endoscopy (WLE) and image enhancement technology (VIST) using Sonoscape HD500 endoscope. GAVE was diagnosed as tortuous columns of ectatic vessels in the gastric antrum. Histopathological examination was used as the standard tool for the diagnosis of GAVE.

Results

A total of 50 patients were included, 28 patients (56 %) were diagnosed as GAVE by pathology vs 22 (44 %) as non-GAVE. Twenty-three of 28 (78.6 %) cases of GAVE were detected by VIST. VIST had superior sensitivity than WLE in the detection of GAVE, 82.1 % vs 7.1 %, while WLE had higher specificity 95.5 % vs 59.1 % by VIST. There was statistical significance between VIST and pathology in the diagnosis of GAVE, p<0.035, but no statistical significance between WLE and pathology. VIST has identified two types of GAVE: focal in 12/28 cases and diffuse in 11/28, and five were not diagnosed by VIST.

Conclusions

Versatile Intelligent Staining Technology could be used as an alternative tool to histopathological diagnosis of GAVE. GAVE can present as a focal group of ectatic vessels which adds a new class to GAVE classification that was previously misdiagnosed.

Endocytoscopic intramucosal capillary network changes and crypt architecture abnormalities can predict relapse in patients with an ulcerative colitis Mayo endoscopic score of 1

OBJECTIVES

Recent studies have suggested the necessity of therapeutic intervention for patients with ulcerative colitis at high risk of clinical relapse with a Mayo endoscopic score (MES) of 1. The aim of this retrospective cohort study was to demonstrate the impact of intramucosal capillary network changes and crypt architecture abnormalities to stratify the risk of relapse in patients with an MES of 1.

METHODS

All included patients had an MES of ≤1 and confirmed sustained clinical remission between October 2016 and April 2019. We classified patients with an MES of 1 as "intramucosal capillary/crypt (ICC)-active" or "ICC-inactive" using endocytoscopic evaluation. We followed patients until October 2019 or until relapse; the main outcome measure was the difference in clinical relapse-free rates between ICC-active and ICC-inactive patients with an MES of 1.

RESULTS

We included 224 patients and analyzed data for 218 (82 ICC-active and 54 ICC-active with an MES of 1 and 82 with an MES of 0). During follow-up, among the patients with an MES of 1, 30.5% (95% confidence interval 20.8-41.6; 25/82) of the patients relapsed in the ICC-active group and 5.6% (95% confidence interval 1.2-15.4; 3/54) of the patients relapsed in the ICC-inactive group. The ICC-inactive group had a significantly higher clinical relapse-free rate compared with the ICC-active group (P < 0.01).

CONCLUSIONS

In vivo intramucosal capillary network and crypt architecture patterns stratified the risk of clinical relapse in patients with an MES of 1 (UMIN 000032580; UMIN 000036359).

Colon polyp detection using linked color imaging compared to white light imaging: Systematic review and meta-analysis

BACKGROUND AND AIM

Linked color imaging (LCI) is a novel image-enhancing technology which enhances color differences between a colorectal lesion and surrounding mucosa with enough brightness to illuminate the wide colorectal lumen. The aim of this study is to compare colorectal polyp detection using LCI with that using white light imaging (WLI).

METHODS

Randomized controlled trials and prospective studies comparing LCI with WLI for colorectal polyp detection were selected. Outcomes included overall polyp/adenoma detection and additional polyp detection at a second observation. Outcomes were documented by pooled risk ratios (RR) with 95% confidence interval (CI) using the Mantel-Haenszel random effect model.

RESULTS

Seven studies were included. LCI showed significant superiority for polyp and adenoma detection compared with WLI (RR 1.16, 95% CI 1.09-1.25, P < 0.001 for polyp detection; RR 1.26, 95% CI 1.14-1.39 P < 0.001 for adenoma detection). LCI significantly increased the number of polyps detected per patient compared with WLI (mean difference 0.27, 95% CI 0.01-0.53, P = 0.040). LCI significantly increased the number of adenomas detected per patient compared with WLI (mean difference 0.22, 95% CI 0.08-0.36, P = 0.002). LCI significantly increased the number of flat polyps detected per patient compared with WLI (mean difference 0.14, 95% CI 0.01-0.27, P = 0.040). LCI had a significantly higher rate of additional polyp detection compared with WLI in the right colon (RR 2.68, 95% CI 1.71-4.19, P < 0.001).

CONCLUSIONS

Linked color imaging has significantly greater polyp and adenoma detection rates and detection rate of previously missed polyps compared with WLI. We recommend the initial use of LCI for routine colonoscopy.

Endoscopic alterations in Peyer's patches in patients with ulcerative colitis: A prospective, multicenter study

BACKGROUND AND AIM

Peyer's patches (PPs) play a major role in intestinal mucosal immunity; however, their role in ulcerative colitis (UC) is not well investigated. We evaluated endoscopic features of PPs on narrow-band imaging with magnifying endoscopy (NBI-ME) and investigated their association with clinical factors.

METHODS

We prospectively recruited 105 patients with UC, 18 with Crohn's disease, 16 with disease control, and 33 healthy control subjects at three institutions from 2014 to 2017. NBI-ME images of the villi of PPs were evaluated according to the Villi Index, and patients were divided into the Villi Index low (L) and high (H) types. The 1-year sustained clinical remission rate was evaluated between L-type and H-type PPs in patients with UC.

RESULTS

The proportions of patients with H-type PPs were significantly higher among UC, Crohn's disease, and disease control patients than among healthy control patients (P = 0.0125, 0.018, 0.0007). In UC, age, gender, endoscopic score, and extent of disease involvement were not significantly different between L-type and H-type PPs, whereas the sustained clinical remission rate was significantly higher in L-type PPs than in H-type PPs (88% [57/65] vs 65% [17/26], P = 0.019). Multivariate analysis revealed that the L type of PPs was a significant factor for sustained clinical remission (odds ratio 3.8, 95% confidence interval 1.1-12.9, P = 0.033).

CONCLUSIONS

Patients with UC showed endoscopic alterations in PPs on NBI-ME, and highly altered appearance of PPs can be associated with a high risk of clinical relapse in patients with UC.

Objective evaluation of the visibility of colorectal lesions using eye tracking

BACKGROUND AND AIM

To assess the visibility of colorectal lesions using blue laser imaging (BLI)-bright and linked-color imaging (LCI) with an eye-tracking system.

METHODS

Eleven endoscopists evaluated 90 images of 30 colorectal lesions. The lesions were randomly selected. Three images of each lesion comprised white light imaging (WLI), BLI-bright, and LCI in the same position. Participants gazed at the images, and their eye movements were tracked by the eye tracker. We analyzed whether the participants could detect the lesion and how long they took to detect the lesion. We assessed the miss rate and detection time among the imaging modalities.

RESULTS

One endoscopist was excluded, and 10 endoscopists were assessed. Overall, 12.6% of lesions were missed with WLI, 6.0% with BLI-bright, and 4.3% with LCI; the miss rate of BLI-bright and LCI was significantly lower than that of WLI (P < 0.01), with no significant difference between the former modalities (P = 0.54). Mean (± SD) detection times were 1.58 ± 1.60 s for WLI, 1.01 ± 1.21 s for BLI-bright, and 1.10 ± 1.16 s for LCI. Detection time for BLI-bright and LCI was significantly shorter than that for WLI (P < 0.0001), with no significant difference between the former modalities (P = 0.34). Regarding the miss rate and detection time between the expert and the non-experts, there was a significant difference with WLI but not with BLI-bright and LCI.

CONCLUSION

Blue laser imaging-bright and LCI improved the detection of colorectal lesions compared with WLI using an eye-tracking system.

Can advanced endoscopic techniques for assessment of mucosal inflammation and healing approximate histology in inflammatory bowel disease?

The targets of therapy in inflammatory bowel disease have transformed in the last few years. The standard definition of mucosal healing assessed using white light standard definition endoscopy is being challenged because even when endoscopy suggests mucosal healing, the presence of histological activity can often still be observed. Of note, microscopic signs of inflammation correlate with clinical outcomes such as risk of relapse, hospitalization and colorectal cancer. Therefore, histological healing has increasingly become an important target to achieve. Advanced endoscopic technologies have been developed and many are starting to be adopted in daily clinical practice. They can provide a more detailed view of the mucosal and vascular architecture almost at the histology level, including crypt, vessel architecture and cellular infiltration. So, these can provide a more accurate definition of mucosal and histological healing. In this review we focus on new advanced endoscopic techniques, and how these have the potential to reduce the gap between histological and mucosal healing.

Role of endoscopy in the surveillance and management of colorectal neoplasia in inflammatory bowel disease

Endoscopy has become increasingly fundamental in the management of patients with inflammatory bowel disease (IBD). It is required for diagnosis, assessment of therapeutic response, postoperative follow up and in the surveillance of dysplasia. With rapid advances in technology, including high definition colonoscopy and chromoendoscopy, questions have arisen regarding the most appropriate surveillance and management strategies of colorectal neoplasia in IBD. We aim to review current surveillance strategies, explore the utility of new technologies, and examine the role of endoscopic resection, with the aim of clarifying these questions.