Confocal laser endomicroscopy for the detection of mucosal changes in ileal pouch after restorative proctocolectomy

Clinically Available Optical Imaging Technologies in Endoscopic Lesion Detection: Current Status and Future Perspective

Endoscopic optical imaging technologies for the detection and evaluation of dysplasia and early cancer have made great strides in recent decades. With the capacity of in vivo early detection of subtle lesions, they allow modern endoscopists to provide accurate and effective optical diagnosis in real time. This review mainly analyzes the current status of clinically available endoscopic optical imaging techniques, with emphasis on the latest updates of existing techniques. We summarize current coverage of these technologies in major hospital departments such as gastroenterology, urology, gynecology, otolaryngology, pneumology, and laparoscopic surgery. In order to promote a broader understanding, we further cover the underlying principles of these technologies and analyze their performance. Moreover, we provide a brief overview of future perspectives in related technologies, such as computer-assisted diagnosis (CAD) algorithms dealing with exploring endoscopic video data. We believe all these efforts will benefit the healthcare of the community, help endoscopists improve the accuracy of diagnosis, and relieve patients' suffering.

Advanced endoscopy imaging in inflammatory bowel diseases

BACKGROUND AND AIMS

Rapid assessment of mucosal inflammation is of crucial importance for the initial diagnosis and the assessment of mucosal healing in inflammatory bowel disease (IBD). Moreover, the identification of intraepithelial neoplasias in IBD is of key relevance for clinical management. Here, we systematically analyzed the utility of advanced endoscopic imaging techniques for optimized diagnosis in IBD.

METHODS

PubMed/Medline, Web of Knowledge, and Cochrane library were searched twice for diagnostic studies on advanced endoscopic imaging in IBD. Clinical and technical information was retrieved and subsequently analyzed. Main outcome parameters consisted of the quality of the results, adverse events, and diagnostic yield.

RESULTS

Fifty-six clinical studies with a total of 3296 patients were selected for final analysis. Filter technologies permitted a more detailed analysis of mucosal inflammation in IBD. In spite of substantial heterogeneity across studies, dye-based chromoendoscopy with targeted biopsy sampling yielded higher detection rates of intraepithelial neoplasias in ulcerative colitis as compared with white-light endoscopy with random biopsy sampling. Moreover, endocytoscopy and endomicroscopy allowed subsurface imaging of inflamed or neoplastic mucosa in IBD at subcellular resolution. Finally, endomicroscopy-aided molecular imaging enabled the identification of membrane-bound tumor necrosis factor on mucosal cells as a potential driver of disease activity in Crohn's disease. No relevant adverse events were reported.

CONCLUSIONS

Advanced endoscopic imaging technologies are feasible, safe, and partially effective tools for detailed diagnosis of mucosal inflammation and detection of neoplasias in IBD. Results obtained from these advanced techniques may provide a rational basis for individualized, optimized therapy for IBD patients.

Early Transcriptomic Changes in the Ileal Pouch Provide Insight into the Molecular Pathogenesis of Pouchitis and Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC) only involves the colonic mucosa. Yet, nearly 50% of patients with UC who undergo total proctocolectomy with ileal pouch anal anastomosis develop UC-like inflammation of the ileal pouch (pouchitis). By contrast, patients with familial adenomatous polyposis (FAP) with ileal pouch anal anastomosis develop pouchitis far less frequently. We hypothesized that pathogenic events associated with the development of UC are recapitulated by colonic-metaplastic transcriptomic reprogramming of the UC pouch.

METHODS

We prospectively sampled pouch and prepouch ileum mucosal biopsies in patients with UC with ileal pouch anal anastomosis 4, 8, and 12 months after their pouch was in continuity. Mucosal samples were also obtained from patients with FAP. Transcriptional profiles of the UC and FAP pouch and prepouch ileum were investigated via RNA sequencing and compared with data from a previously published microarray study.

RESULTS

Unlike patients with FAP, subjects with UC exhibited a large set of differentially expressed genes between the pouch and prepouch ileum as early as 4 months after pouch functionalization. Functional pathway analysis of differentially expressed genes in the UC pouch revealed an enhanced state of immune/inflammatory response and extracellular matrix remodeling. Moreover, >70% of differentially expressed genes mapped to published inflammatory bowel diseases microarray data sets displayed directional changes consistent with active UC but not with Crohn's disease.

CONCLUSIONS

The UC pouch, well before histologic inflammation, already displays a systems-level gain of colon-associated genes and loss of ileum-associated genes. Patients with UC exhibit a unique transcriptomic response to ileal pouch creation that can be observed well before disease and may in part explain their susceptibility to the development of pouchitis.

Confocal Laser Endomicroscopy in Gastrointestinal and Pancreatobiliary Diseases: A Systematic Review and Meta-Analysis

Confocal laser endomicroscopy (CLE) is an endoscopic-assisted technique developed to obtain histopathological diagnoses of gastrointestinal and pancreatobiliary diseases in real time. The objective of this systematic review is to analyze the current literature on CLE and to evaluate the applicability and diagnostic yield of CLE in patients with gastrointestinal and pancreatobiliary diseases. A literature search was performed on MEDLINE, EMBASE, Scopus, and Cochrane Oral Health Group Specialized Register, using pertinent keywords without time limitations. Both prospective and retrospective clinical studies that evaluated the sensitivity, specificity, or accuracy of CLE were eligible for inclusion. Of 662 articles identified, 102 studies were included in the systematic review. The studies were conducted between 2004 and 2015 in 16 different countries. CLE demonstrated high sensitivity and specificity in the detection of dysplasia in Barrett's esophagus, gastric neoplasms and polyps, colorectal cancers in inflammatory bowel disease, malignant pancreatobiliary strictures, and pancreatic cysts. Although CLE has several promising applications, its use has been limited by its low availability, high cost, and need of specific operator training. Further clinical trials with a particular focus on cost-effectiveness and medicoeconomic analyses, as well as standardized institutional training, are advocated to implement CLE in routine clinical practice.

The role of endoscopy in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of chronic immune-mediated disorders of the gastrointestinal tract. It is often the result of the interaction of genetic and environmental factors. The role of endoscopy in disease surveillance is unprecedented. However, there is considerable debate in therapeutic goals in IBD patients, ranging from the resolution of clinical symptoms to mucosal healing. Furthermore, deep remission has recently been advocated for altering disease course in these patients. Additionally, neoplasia continues to be a significant cause of morbidity and mortality in IBD patients. This review discussed the role of several endoscopic techniques in assessing mucosal healing and neoplasia with emphasis on novel non-invasive endoscopic techniques.

Confocal Laser Endomicroscopy in Inflammatory Bowel Disease--A Systematic Review

BACKGROUND AND AIMS

Confocal laser endomicroscopy is an endoscopic method that provides in vivo real-time imaging of the mucosa at a cellular level, elucidating mucosal changes that are undetectable by white light endoscopy. This paper systematically reviews current indications and perspectives of confocal laser endomicroscopy for inflammatory bowel disease.

METHODS

Available literature was searched systematically for studies applying confocal laser endomicroscopy in Crohn's disease or ulcerative colitis. Relevant literature was reviewed and only studies reporting original clinical data were included. Next, eligible studies were analysed with respect to several parameters, such as technique and clinical aim and definitions of outcomes.

RESULTS

Confocal laser endomicroscopy has been used for a wide range of purposes in inflammatory bowel disease, covering assessment of inflammatory severity, prediction of therapeutic response and relapse and adenoma surveillance in patients with ulcerative colitis. Methods for measurement of the histological changes ranged from subjective grading to objective quantification analysed by computer-aided models. The studies derived their conclusions from assessment of histological features such as colonic crypts, epithelial gaps and epithelial leakiness to fluorescein.

CONCLUSIONS

Confocal laser endomicroscopy remains an experimental but emerging tool for assessment of inflammatory bowel disease. It is the only method that enables in vivo functional assessment of intestinal barrier function. There is great heterogeneity in the literature and no single approach has been validated and reproduced to the level of general acceptance.

Differential diagnosis in inflammatory bowel disease colitis: State of the art and future perspectives

Distinction between Crohn’s disease of the colon-rectum and ulcerative colitis or inflammatory bowel disease (IBD) type unclassified can be of pivotal importance for a tailored clinical management, as each entity often involves specific therapeutic strategies and prognosis. Nonetheless, no gold standard is available and the uncertainty of diagnosis may frequently lead to misclassification or repeated examinations. Hence, we have performed a literature search to address the problem of differential diagnosis in IBD colitis, revised current and emerging diagnostic tools and refined disease classification strategies. Nowadays, the differential diagnosis is an untangled issue, and the proper diagnosis cannot be reached in up to 10% of patients presenting with IBD colitis. This topic is receiving emerging attention, as medical therapies, surgical approaches and leading prognostic outcomes require more and more disease-specific strategies in IBD patients. The optimization of standard diagnostic approaches based on clinical features, biomarkers, radiology, endoscopy and histopathology appears to provide only marginal benefits. Conversely, emerging diagnostic techniques in the field of gastrointestinal endoscopy, molecular pathology, genetics, epigenetics, metabolomics and proteomics have already shown promising results. Novel advanced endoscopic imaging techniques and biomarkers can shed new light for the differential diagnosis of IBD, better reflecting diverse disease behaviors based on specific pathogenic pathways.

Systematic review of cuff and pouch cancer in patients with ileal pelvic pouch for ulcerative colitis

BACKGROUND

Ileal pouch-anal anastomosis (IPAA) is the procedure of choice for refractory or complicated ulcerative colitis (UC). Since 1990, pouch-related adenocarcinomas have been described. The aim of this study was to review the literature to evaluate the burden of this complication, seeking for risk factors, prevention, and ideal management.

METHODS

We performed a systematic review of the literature to identify all described pouch-related adenocarcinoma in patients operated on with IPAA for UC. Studies were thoroughly evaluated to select authentic de novo pouch carcinomas. Some authors were contacted for additional information. Data of patients were pooled. Meta-analyses of suitable studies were attempted to identify risk factors.

RESULTS

Thirty-four articles reported on 49 patients (2:1, male:female) who developed unequivocal pouch-related adenocarcinoma, 14 (28.6%) and 33 (67.3%) arising from the pouch and anorectal mucosa, respectively. Origin was not reported in 2 (4%). Pooled cumulative incidence of pouch-related adenocarcinoma was 0.33% (95% confidence interval [CI], 0.31-0.34) 50 years after the diagnosis and 0.35% (95% CI, 0.34-0.36) 20 years after IPAA. Primary pouch cancer incidence was below 0.02% 20 years after IPAA. Neoplasia on colectomy specimen was the strongest risk factor (odds ratio, 8.8; 95% CI, 4.61-16.80). Mucosectomy did not abolish the risk of subsequent cancer but avoiding it increased 8 times the risk of cancer arising from the residual anorectal mucosa (odds ratio, 8; 95% CI, 1.3-48.7; P = 0.02). Surveillance is currently performed yearly starting 10 years since diagnosis, but cancers escaping this pathway are reported. In patients receiving mucosectomy, a 5-year delay for surveillance could be proposed.

CONCLUSIONS

Pouch-related adenocarcinomas are rare. Diagnosis of Crohn's disease in the long term may further decrease the rates in UC. Presumed evolution from dysplasia might offer a time window for cancer prevention. Abdominoperineal excision should be recommended for pouch-related adenocarcinomas.

Advanced endoscopic imaging techniques in Crohn's disease

BACKGROUND

Endoscopy is of pivotal importance in Crohn's disease (CD) patients for diagnosis, surveillance and assessment of disease activity and extent. Device-assisted enteroscopy (DAE) and small-bowel capsule endoscopy (SBCE) have recently changed our endoscopic approach to small-bowel imaging. Furthermore, new advanced endoscopic imaging techniques have been implemented into clinical practice to improve both characterization of mucosal inflammation and detection of dysplastic lesions.

AIM

To provide readers with a review about the concept of advanced endoscopic imaging for the diagnosis and characterization of CD.

METHODS

A literature search on the use of advanced endoscopy techniques in IBD patients was performed.

RESULTS

DAE and SBCE allow for deep enteroscopy with high diagnostic yields and low complication's rate but their collocation in the diagnostic algorithm is still not clearly defined. Dye-based chromoendoscopy (DBC) and magnification chromoendoscopy improved dysplasia's detection in long standing colitis and prediction of inflammatory activity and extent. Dye-less chromoendoscopy (DLC) might offer the potential to replace conventional DBC for surveillance. However, both narrow band imaging and i-scan have already shown to significantly improve activity and extent assessment in comparison to white-light endoscopy. Confocal laser endomicroscopy (CLE) can detect more dysplastic lesions in surveillance colonoscopy and predict neoplastic and inflammatory changes with high accuracy compared to histology. Moreover, CLE-based molecular imaging may anticipate the therapeutic responses to biological therapy. Endocytoscopy can identify in vivo inflammatory mucosal cells harboring a new method to assess the mucosal activity.

CONCLUSIONS

Recent progresses in small-bowel enteroscopy offer several potential benefits to improve both diagnosis and characterization of CD. New advanced endoscopic imaging techniques can improve detection of dysplasia and refine mucosal healing assessment, even looking beyond the morphological parameters revealed by conventional endoscopic imaging.

Endomicroscopy and endocytoscopy in IBD

Two types of endomicroscopy systems exist. One is integrated into a standard, high-resolution endoscope and one is probe-based, capable of passage through the working channel of a standard endoscope. Endocytoscopy allows visualization of the superficial mucosal layer. Endoscope-integrated and probe-based devices allow magnification of the mucosa up to 1400-fold. Endomicroscopy can differentiate histologic changes of Crohn disease and ulcerative colitis in vivo in real time. Endocytoscopy can discriminate mucosal inflammatory cells, allowing determination of histopathologic activity of ulcerative colitis. Molecular imaging with fluorescence-labeled probes against disease-specific receptors will enable individualized management of inflammatory bowel diseases.

Histopathological evaluation and risk factors related to the development of pouchitis in patients with ileal pouches for ulcerative colitis

OBJECTIVE

Many changes in mucosal morphology are observed following ileal pouch construction, including colonic metaplasia and dysplasia. Additionally, one rare but potential complication is the development of adenocarcinoma of the reservoir. The aim of this study was to evaluate the most frequently observed histopathological changes in ileal pouches and to correlate these changes with potential risk factors for complications.

METHODS

A total of 41 patients were enrolled in the study and divided into the following three groups: a non-pouchitis group (group 1) (n = 20; 8 males; mean age: 47.5 years) demonstrating optimal outcome; a pouchitis without antibiotics group (group 2) (n = 14; 4 males; mean age: 47 years), containing individuals with pouchitis who did not receive treatment with antibiotics; and a pouchitis plus antibiotics group (group 3) (n = 7; 3 males; mean age: 41 years), containing those patients with pouchitis who were administered antibiotics. Ileal pouch endoscopy was performed, and tissue biopsy samples were collected for histopathological analysis.

RESULTS

Colonic metaplasia was found in 15 (36.6%) of the 41 patients evaluated; of these, five (25%) were from group 1, eight (57.1%) were from group 2, and two (28.6%) were from group 3. However, no correlation was established between the presence of metaplasia and pouchitis (p = 0.17). and no differences in mucosal atrophy or the degree of chronic or acute inflammation were observed between groups 1, 2, and 3 (p>0.45). Moreover, no dysplasia or neoplastic changes were detected. However, the degree of mucosal atrophy correlated well with the time of postoperative follow-up (p = 0.05).

CONCLUSIONS

The degree of mucosal atrophy, the presence of colonic metaplasia, and the degree of acute or chronic inflammation do not appear to constitute risk factors for the development of pouchitis. Moreover, we observed that longer postoperative follow-up times were associated with greater degrees of mucosal atrophy.

Technicalities of colonoscopy: endoscopic microscopy - where are we heading?

Confocal laser endomicroscopy (CLE) is a new endoscopic imaging tool enabling in vivo histology during ongoing endoscopy. Basically, three different patterns can be seen in the colon: normal, neoplastic and inflammatory mucosa. Several pilot studies have shown an excellent correlation with classical histology. However, what could be the future indications of CLE? (1) Differentiating neoplastic from inflammatory changes constitutes a promising diagnostic tool in screening for dysplasia in ulcerative colitis. This can help to further increase the efficacy of chromoendoscopy in dysplasia detection and reduce the number of biopsies. The possibility to differentiate sporadic adenoma from dysplasia-associated lesion or mass could have an immediate impact on patient management. (2) The diagnosis of collagenous colitis depends on multiple random biopsies. Case series have shown that CLE can guide the endoscopist to take more representative biopsies to make the diagnosis. Large prospective trials are needed to confirm this finding. (3) An interesting clinical application is graft-versus-host disease (GVHD). A pilot study showed that it was possible to predict the presence of GVHD in 14/19 patients with GVHD out of 35 patients who were referred for diarrhea after stem cell transplantation. (4) CLE for standard polyp surveillance is probably redundant since it will not change patient management at this stage. Moreover, it can currently not differentiate between classical hyperplastic and sessile serrated adenomas. (5) Future additional technological improvements of the system with faster Z-scanning, deeper light penetration and 3D reconstruction will help to improve the quality of CLE. Reports on in vivo molecular imaging and assessment of physiological changes provide a promising glance at the future possibilities of CLE imaging.