Image-enhanced endoscopy is critical in the surveillance of patients with colonic IBD

Moxifloxacin promotes two-photon microscopic imaging for discriminating different stages of DSS-induced colitis on mice

BACKGROUND

Accurate diagnosis of patients with ulcerative colitis (UC) can reduce their risk of developing colorectal cancer. This study intended to explore whether moxifloxacin, an agent with fluorescence potential, could promote two-photon microscopy (TPM) diagnosis for mice with dextran sodium sulfate (DSS)-induced colitis, which could imitate human UC.

METHODS

32 Balb/c mice were randomly divided into 4 groups: control, acute colitis, remission colitis and chronic colitis. Fluorescence parameters, imaging performance, and tissue features of different mouse models were compared under moxifloxacin-assisted TPM and label-free TPM.

RESULTS

Excitation wavelength of 720 nm and moxifloxacin labeling time of 2 min was optimal for moxifloxacin-assisted TPM. With moxifloxacin labeling for colonic tissues, excitation power was decreased to 1/10 of that without labeling while fluorescence intensity was increased to 10-fold of that without labeling. Photobleaching was negligible after moxifloxacin labeling and moxifloxacin fluorescence kept stable within 2 h. Compared with the control group, moxifloxacin fluorescence was reduced in the three colitis groups (P < 0.05). Meanwhile, the proportion of enhanced moxifloxacin fluorescence regions was (22.4 ± 1.6)%, (7.7 ± 1.0)%, (13.5 ± 1.7)% and (5.0 ± 1.3)% in the control, acute, remission and chronic groups respectively, with significant reduction in the three colitis groups (P < 0.05). Besides, variant tissue features of experimental colitis models were presented under moxifloxacin-assisted TPM, such as crypt opening, glandular structure, adjacent glandular space and moxifloxacin distribution.

CONCLUSIONS

With unique biological interaction between moxifloxacin and colonic mucosa, moxifloxacin-assisted TPM imaging is feasible and effective for accurate diagnosis of different stages of experimental colitis.

Augmented Endoscopy for Surveillance of Colonic Inflammatory Bowel Disease: Systematic Review With Network Meta-analysis

INTRODUCTION

Considering the high risk of dysplasia and cancer in inflammatory bowel disease [IBD], surveillance is advocated. However, international guidelines do not reach a uniform recommendation on the way to perform surveillance. We performed a systematic review with a meta-analysis to assess the best endoscopic surveillance strategy in colonic IBD.

METHODS

The systematic review was performed in PubMed/MEDLINE, EMBASE, SCOPUS, and Cochrane databases to identify studies comparing white light endoscopy [WLE] and augmented endoscopy [AE] in the detection of dysplasia/neoplasia in colonic IBD. A sub-analysis between dye-spray chromoendoscopy [DCE], narrow-band imaging [NBI], I-SCAN, full-spectrum endoscopy [FUSE], and auto-fluorescence imaging [AFI] was also performed. Furthermore, a meta-regression and a network meta-analysis were also performed.

RESULTS

A total of 27 studies [6167 IBD patients with 2024 dysplastic lesions] met the inclusion criteria. There was no publication bias. AE showed a higher likelihood of detecting dysplasia than WLE (19.3% vs 8.5%, odds ratio [OR] = 2.036), with an incremental yield [IY] of 10.8%. DCE [OR = 2.605] and AFI [OR = 3.055] had higher likelihood of detecting dysplasia than WLE; otherwise, I-SCAN [OR = 1.096], NBI [OR = 0.650], and FUSE [OR = 1.118] were not superior to WLE. Dysplasia was found in 1256/7267 targeted biopsies [17.3%] and in 363/110 040 random biopsies [0.33%] [OR = 66.559, IY = 16.9%]. Meta-regression found no variable impacting on the efficacy of AE techniques. Network meta-analysis identified a significant superiority of DCE to WLE in detecting dysplasia [OR 2.12], but no other single technique was found to be superior to all others in dysplasia detection.

CONCLUSIONS

DCE was associated with higher likelihood of discovering dysplastic lesions than WLE. Chromoendoscopy is the best supported endoscopic technique for IBD surveillance.

Chromoendoscopy for Dysplasia Surveillance in Inflammatory Bowel Disease

Long-standing ulcerative colitis (UC) and extensive Crohn's colitis confer increased risk for development of colorectal cancer. Screening and surveillance colonoscopy programs aim to identify, resect, or detect dysplasia or colorectal cancer. Dysplastic lesions can be removed by endoscopic resection and patients with unresectable lesions can be referred for colectomy at an earlier stage, with the goal of reducing overall morbidity and mortality from colorectal cancer. Surveillance colonoscopy for patients with inflammatory bowel disease (IBD) is endorsed by multiple specialty societies. High-definition endoscopy systems provide improved image resolution, and application of dilute indigo carmine or methylene blue for chromoendoscopy can provide increased contrast. International specialty society guidelines differ in their recommendations regarding use of chromoendoscopy for dysplasia surveillance, with some guidelines advocating a risk-stratified surveillance strategy. In this review, we discuss chromoendoscopy technique, training, implementation, yield as compared with standard-definition and high-definition white light colonoscopy, and positioning of this technique in clinical practice.

Surveillance strategies for colitis-associated cancer: state of the art and future perspectives

Colitis-associated cancer (CAC) represents a concrete risk of morbidity and mortality in patients with long lasting inflammatory bowel diseases. Surveillance colonoscopy is a rapidly evolving research field with profound changes from the traditional approach based on scheduled controls and random biopsy protocols. Areas covered: A literature search was performed using PubMed/Embase to review the latest evidence supporting the need for surveillance colonoscopy. By focusing on the most promising recent advances in this field, we provide a state-of-the-art overview of the current gold standards for the diagnosis and management of colitis-associated dysplasia. Expert commentary: Evidence-based and emerging data have questioned the efficacy and effectiveness of both standard surveillance colonoscopy and random biopsy protocols. The latest guidelines endorse early initiation of surveillance programs, risk-profiling assessment of colonoscopy intervals and standardized use of advanced imaging modalities to detect early dysplasia. Current trends clearly reveal increased attention to direct visualization and endoscopic management of visible dysplastic lesions, even in patients with longstanding colitis. Emerging technological advances in gastrointestinal endoscopy are expected to change the endoscopic surveillance protocols in the near future.

Crohn's disease: risk factor for colorectal cancer

Background Crohn's disease is an inflammatory disease that can reach any part of the gastrointestinal tract. This disease has been associated with an increased neoplastic risk, including colorectal carcinoma.

Objective The objective of this work is to describe the mechanisms present in two diseases, and that are responsible for the increased risk in Crohn's disease.

Methods A bibliographic research was conducted in PubMed database. In addition to the articles obtained with an inserted query in Pubmed, other references relevant to the topic in question were included.

Results Colorectal cancer risk varies according to the presence of certain factors, and an example of this is Crohn's disease. Chronic inflammation seems to be an important contribution to carcinogenesis, since it creates a microenvironment suitable for the onset and progression of the disease. There are molecular changes that are common to two conditions, thus justifying the fact of Crohn's disease being a risk factor for colorectal carcinoma. The disease control with an appropriate therapy and with surveillance are two ways to control this risk.

Conclusions A proinflammatory state is the cornerstone in the association between Crohn's disease and colorectal carcinoma. The implementation of surveillance strategies allowed a decrease in morbidity and mortality associated with this cancer.

Advanced imaging in colonoscopy: contemporary approach to dysplasia surveillance in inflammatory bowel disease

Inflammatory bowel disease (IBD) (ulcerative colitis (UC) and Crohn's disease (CD)) is a chronic relapsing/remitting condition characterised by intestinal inflammation. One of the main concerns in patients with longstanding ulcerative and Crohn's colitis is development of colonic dysplasia and colorectal cancer (CRC), a risk higher than that of the general population. Colonoscopy surveillance programmes have been developed by major societies worldwide to improve early dysplasia detection and treatment, thus preventing progression to colorectal cancer. Colonoscopy is an imperfect tool as lesions can be missed, an issue even more relevant to colitic patients, where mucosal inspection and lesion recognition may prove challenging. Extensive research has been undertaken on performance improvement in this area while technical advances in optical imaging, such as high-definition, have made their way into modern endoscopy units. Techniques and technologies available to enhance optical diagnosis of dysplasia in inflammatory bowel disease are reviewed in this paper, focusing on those that are realistic, widely available and feasible for everyday practice.

Advances in endoscopic imaging in ulcerative colitis

Modern strategies for the treatment of ulcerative colitis require more accurate tools for gastrointestinal imaging to better assess mucosal disease activity and long-term prognostic clinical outcomes. Recent advances in gastrointestinal luminal endoscopy are radically changing the role of endoscopy in every-day clinical practice and research trials. Advanced endoscopic imaging techniques including high-definition endoscopes, optical magnification endoscopy, and various chromoendoscopy techniques have remarkably improved endoscopic assessment of ulcerative colitis. More recently, optical biopsy techniques with either endocytoscopy or confocal laser endomicroscopy have shown great potential in predicting several histological changes in real time during ongoing endoscopy. Here, we review current applications of advanced endoscopic imaging techniques in ulcerative colitis and present the most promising upcoming headways in this field.

Endoscopy in the Diagnosis and Management of Complications of Inflammatory Bowel Disease

The role of endoscopy in inflammatory bowel disease (IBD) has grown over the last decade in both diagnostic and therapeutic realms. It aids in the initial diagnosis of the disease and also in the assessment of the extent and severity of disease. IBD is associated with development of multiple complications such as strictures, fistulae, and colon cancers. Endoscopy plays a pivotal role in the diagnosis of colon cancer in patients with IBD through incorporation of chromoendoscopy for surveillance. In addition, endoscopic resection with surveillance is recommended in the management of polypoid dysplastic lesions without flat dysplasia. IBD-associated benign strictures with obstructive symptoms amenable to endoscopic intervention can be managed with endoscopic balloon dilation both in the colon and small intestine. In addition, endoscopy plays a major role in assessing the neoterminal ileum after surgery to risk-stratify patients after ileocolonic resection and assessment of a patient with ileoanal pouch anastomosis surgery and management of postsurgical complications. Our article summarizes the current evidence in the role of endoscopy in the diagnosis and management of complications of IBD.

Novel Hexosaminidase-Targeting Fluorescence Probe for Visualizing Human Colorectal Cancer

Precise tumor diagnosis and evaluation of disease extent are crucial for treatment of solid cancers. In order to complement the limited ability of the unaided human eye to discriminate tumor tissue and normal tissue, we have developed a series of fluorescence probes activatable specifically in cancer tissues. Here, we describe the design, synthesis, and application of a new fluorescence probe targeting hexosaminidase (HMRef-βGlcNAc), which is located in lysosomes and is overexpressed in several carcinomas, including colorectal cancer. This probe could sensitively detect intracellular hexosaminidase activity in human colorectal cancer cell lines, and could visualize tiny metastatic nodules (smaller than 1 mm) in a mouse model of disseminated human peritoneal colorectal cancer (HCT116). In human colorectal cancer specimens obtained at surgery, the probe showed high tumor sensitivity/specificity, together with a high tumor-to-normal signal ratio. HMRef-βGlcNAc is a promising candidate for clinical application during surgical or endoscopic procedures to treat colorectal cancer.

Advanced endoscopic features of ulcerative colitis-associated neoplasias: Quantification of autofluorescence imaging

Ulcerative colitis (UC) patients are well known to carry a higher risk of developing colorectal dysplasia/cancer. However, it is hard to detect the lesion in the early phase during colonoscopy. This pilot study was conducted to analyze the endoscopic characteristics of neoplastic lesions associated with UC using advanced imaging techniques. This is a retrospective analysis of 15 colorectal neoplastic lesion obtained from 11 UC patients during remission who underwent white-light- and advanced endoscopic imaging techniques, including chromoendoscopy, narrow-band imaging and autofluorescence imaging (AFI), and were treated with surgery. These lesions were analyzed for histology, location, size, shape, color and endoscopic features. The green/red ratio was also assessed to quantify the AFI intensity. All 11 patients had extensive colitis with the median disease duration of 14.0 years. A total of 15 lesions, consisting of 8 high-grade dysplasia and 7 cancer, was mostly located in the distal colon (86.7%, 13/15) with the mean size of 8.6 mm. The shape was protruding in 46.7% (7/15), flat elevated in 40.0% (6/15) and flat in 13.3% (2/15) and the color was red in 60.0% (9/15), same colored in 33.3% (5/15) and discolored in 6.7% (1/15). The lesion predominantly showed Kudo's neoplastic pit pattern in 86.7% (13/15; 5 type IIIL, 7 type IV and 1 type VI) on chromoendoscopy and Sano's neoplastic capillary pattern (type IIIa) in 63.6% (7/11) on narrow-band imaging, but were colored purple as neoplastic lesions in only 37.5% (3/8) on AFI. Of note, the AFI green/red ratio was significantly lower in the neoplastic lesions than UC-involved areas (p=0.00014) and UC-uninvolved areas (p=0.00651) irrespective of the lesion's size and histological type. In conclusion, endoscopic analysis based on advanced imaging, in particular AFI quantitation, may be helpful to detect early stage neoplastic lesions in long standing UC. Large-scale, prospective studies are needed.

Advances in the Endoscopic Assessment of Inflammatory Bowel Diseases: Cooperation between Endoscopic and Pathologic Evaluations

Endoscopic assessment has a crucial role in the management of inflammatory bowel disease (IBD). It is particularly useful for the assessment of IBD disease extension, severity, and neoplasia surveillance. Recent advances in endoscopic imaging techniques have been revolutionized over the past decades, progressing from conventional white light endoscopy to novel endoscopic techniques using molecular probes or electronic filter technologies. These new technologies allow for visualization of the mucosa in detail and monitor for inflammation/dysplasia at the cellular or sub-cellular level. These techniques may enable us to alter the IBD surveillance paradigm from four quadrant random biopsy to targeted biopsy and diagnosis. High definition endoscopy and dye-based chromoendoscopy can improve the detection rate of dysplasia and evaluate inflammatory changes with better visualization. Dye-less chromoendoscopy, including narrow band imaging, iScan, and autofluorescence imaging can also enhance surveillance in comparison to white light endoscopy with optical or electronic filter technologies. Moreover, confocal laser endomicroscopy or endocytoscopy have can achieve real-time histology evaluation in vivo and have greater accuracy in comparison with histology. These new technologies could be combined with standard endoscopy or further histologic confirmation in patients with IBD. This review offers an evidence-based overview of new endoscopic techniques in patients with IBD.

Chromocolonoscopy

Chromoendoscopy techniques improve the visualization of mucosal structures. This article reviews and summarizes key studies addressing the impact of chromoendoscopy on colonic neoplasia detection and differentiation of neoplastic from non-neoplastic polyps in average and high-risk populations, including patients with colonic inflammatory bowel disease (IBD). In this context, there are convincing data that chromoendoscopy differentiates neoplastic from non-neoplastic polyps in average-risk populations with high accuracy. Moreover, dye-based chromoendoscopy improves neoplasia detection in colonic IBD surveillance.