Endoscopic imaging of angiogenesis in vivo

pCLE detects mucosal neoplastic vascular pattern in gastric linitis plastica

Linitis plastica (LP) is a very aggressive and rare carcinoma with a scirrhous stroma that affects the submucosal and muscular layers of the stomach even without mucosal alterations. Lack of timely diagnosis is a crucial problem related to its prognosis and treatment. In this study, we investigated the LP-associated vascular pattern as a possible means to improve the diagnosis of these patients. During standard endoscopy, mucosal architecture, tortuosity and enlargement of vessels, as well as the presence of vascular leakage and efficiency of the blood flow were assessed in six LP patients using probe-based Confocal Laser Endomicroscopy (pCLE). In all LP patients, we detected abnormal changes in vasculature. The aberrant features of the vascular network were common to all LP patients examined and consisted of vessel enlargement, tortuosity, and leakage associated with the affected submucosal layer. This is the first study to highlight the presence of marked vascularization associated with LP, characterized by the presence of abnormal and non-functional vessels, similar to what is observed in neoplastic tissues. Therefore, the analysis of LP by pCLE may provide a new endoscopic approach and strategy to better define these patients.

pCLE highlights distinctive vascular patterns in early gastric cancer and in gastric diseases with high risk of malignant complications

Endoscopy is widely used to detect and diagnose precancerous lesions and gastric cancer (GC). The probe-based Confocal Laser Endomicroscopy (pCLE) is an endoscopic technique suitable for subcellular resolution and for microvasculature analyses. The aim of this study was to use pCLE to identify specific vascular patterns in high-risk and early stage GC. Mucosal architecture, vessel tortuosity, enlargements and leakage were assessed in patients with autoimmune gastritis and early gastric cancer (EGC). We were able to stratify gastritis patients by identifying distinct vascular profiles: gastritis was usually associated with increased vascularization characterized by a high number of tortuous vessels, which were also found in atrophic autoimmune disease. Leaky and tortuous vessels, distributed in a spatially irregular network, characterized the atrophic metaplastic mucosa. The mucosal vasculature of EGC patients displayed tortuous vessels, but unlike what detected in atrophic gastritis, they appeared patchy, as is in neoplastic gastric tissue. Very importantly, we detected vascular changes even in areas without lesions, supporting the contention that vascular alterations may provide a favorable microenvironment for carcinogenesis. This report confirms that pCLE is a valid endoscopic approach to improve the definition of patients with malignant lesions or at increased risk for GC by assessing vascular changes.

A positive feedback loop consisting of C12orf59/NF-κB/CDH11 promotes gastric cancer invasion and metastasis

Background

Metastasis remains the main cause of cancer-related death for gastric cancer (GC) patients, but the mechanisms are poorly understood. Using The Cancer Genome Atlas (TCGA) data base and bioinformatics analyses, we identified C12orf59 might act as a potential oncogenic protein in GC.

Methods

We investigate the expression pattern and clinical significance of C12orf59 in two independent cohorts of GC samples. In the training cohort, we used the X-tile program software to generate the optimal cutoff value for C12orf59 expression in order to classify patients accurately according to clinical outcome. In the validation cohort, this derived cutoff score was applied to exam the association of C12orf59 expression with survival outcome. A series of in vivo and in vitro assays were then performed to investigate the function of C12orf59 in GC.

Results

C12orf59 was significantly upregulated, and associated with poor survival outcome in two cohorts of GC samples. Gain- and loss of- function studies demonstrated C12orf59 promotes GC cell invasive and metastatic capacity both in vitro and in vivo, and induces epithelial–mesenchymal transition and angiogenesis. Mechanically, C12orf59 exerts oncogenic functions by up-regulating CDH11 expression via NF-κB signaling. Interesting, CDH11 could in turn promote NF-κB bind to C12orf59’s promoter and form a positive feedback loop to sustain the metastatic ability of GC cells. Additionally, downregulation of miR-654-5p is another important mechanism for C12orf59 overexpression in GC.

Conclusion

Our finding suggested the newly identified C12orf59/NF-κB/CDH11 feedback loop may represent a new strategy for GC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1114-2) contains supplementary material, which is available to authorized users.

Probe-based confocal laser endomicroscopy for in vivo evaluation of the tumor vasculature in gastric and rectal carcinomas

Probe-based Confocal Laser Endomicroscopy (pCLE) is a powerful imaging technique that allows to perform gastrointestinal endomicroscopy at subcellular resolution. The aim of this study was to assess the use of pCLE to evaluate tumor angiogenesis in rectal and gastric cancers. A total of 35 consecutive patients with gastric and 91 with rectal carcinomas underwent endoscopy and pCLE during the same examination. Vascular assessment was based on vessel shape and size, vessel permeability and blood flow, and allowed the creation of an angiogenic score ranging from 0, for normal vasculature, to 4, for aberrant vasculature. A significant difference for the presence of vessels with large diameter and defective blood flow was found between rectal and gastric cancers. Overall, rectal cancers displayed a higher angiogenic score compared to gastric cancers. Conventional therapy induced a striking reduction in the angiogenic score only in rectal cancer patients. Taken together, our findings suggest that the pCLE technology is suitable for the evaluation of the tumor microvasculature abnormalities. Therefore, the real-time assessment of the vasculature status may represent a promising approach to predict the efficacy of the treatments and improve the clinical management of patients with gastric or rectal carcinomas.

In vivo assessment of tumour angiogenesis in colorectal cancer: the role of confocal laser endomicroscopy

AIM

Tumour neoangiogenesis is a key factor in tumour progression and metastatic spread and the possibility to assess tumour angiogenesis might provide prognostic information. The aim of this study was to establish the role of probe-based confocal laser endomicroscopy (p-CLE) in the identification of vascular architecture and specific morphological patterns in normal colorectal mucosa and malignant lesions during routine endoscopy.

METHOD

Fourteen consecutive patients with colorectal cancer were included. The following features were identified and then compared between normal and neoplastic mucosa on p-CLE images: vessel shape (straight vs irregular) vessel diameter the 'branching patterns' vessel permeability (fluorescein leakage) and blood flow (normal vs defective flux). Immunohistochemistry was used to confirm the presence and to study the morphology of vascular structures (CD-34 staining) and 'neo-vessels' (WT-1 staining) on tumour and normal mucosal sections.

RESULTS

Tumour vessels appeared as irregular, ectatic and with a highly variable calibre and branching patterns on p-CLE images. The mean diameter of tumour vessels was significantly larger than those in normal mucosa (weighted mean difference 3.38, 95% CI 2.65-4.11, P = 0.01). Similarly, 'vessel branching' (OR 2.74, 95% CI 1.23-6.14, P = 0.01), fluorescent dye 'extravasation' (OR 3.46, 95% CI 1.39-8.57, P = 0.01) were significantly more frequent in colorectal cancer than in normal colorectal mucosa. Immunohistochemistry corroborated the p-CLE findings, showing higher vascularity in tumour sections due to neoformed vessels, presenting irregular patterns.

CONCLUSION

Probe-based confocal laser endomicroscopy provides a noninvasive characterization of the microvascular architecture of colonic mucosa. Different morphological patterns have been described, discriminating normal and malignant microvascular networks in colorectal mucosa.

Probe based confocal laser endomicroscopy of the pancreatobiliary system

AIM

To review applications of confocal laser endomicroscopy (CLE) in pancreatobiliary lesions and studies that assessed training and interpretation of images.

METHODS

A computerized literature search was performed using OVID MEDLINE, EMBASE, Cochrane library, and the ISI Web of Knowledge from 1980 to October 2014. We also searched abstracts from major meetings that included the Digestive Disease Week, Canadian Digestive Disease Week and the United European Gastroenterology Week using a combination of controlled vocabulary and text words related to pCLE, confocal, endomicroscopy, probe-based confocal laser endomicroscopy, and bile duct to identify reports of trials. In addition, recursive searches and cross-referencing was performed, and manual searches of articles identified after the initial search was also completed. We included fully published articles and those in abstract form. Given the relatively recent introduction of CLE we included randomized trials and cohort studies.

RESULTS

In the evaluation of indeterminate pancreatobiliary strictures CLE with ERCP compared to ERCP alone can increase the detection of cancerous strictures with a sensitivity of (98% vs 45%) and has a negative predictive value (97% vs 69%), but decreased the specificity (67% vs 100%) and the positive predictive value (71% vs 100%) when compared to index pathology. Modifications in the classification systems in indeterminate biliary strictures have increased the specificity of pCLE from 67% to 73%. In pancreatic cystic lesions there is a need to develop similar systems to interpret and characterize lesions based on CLE images obtained. The presence of superficial vascular network predicts serous cystadenomas accurately. Also training in acquiring and interpretation of images is feasible in those without any prior knowledge in CLE in a relatively simple manner and computer-aided diagnosis software is a promising innovation.

CONCLUSION

The role of pCLE in the evaluation of pancreatobiliary disorders might be better suited for those with an intermediate and low probability.

Evaluation of new morphometric parameters of neoangiogenesis in human colorectal cancer using confocal laser endomicroscopy (CLE) and targeted panendothelial markers

The tumor microcirculation is characterized by an abnormal vascular network with dilated, tortuous and saccular vessels. Therefore, imaging the tumor vasculature and determining its morphometric characteristics represent a critical goal for optimizing the cancer treatment that targets the blood vessels (i.e. antiangiogenesis therapy). The aim of this study was to evaluate new vascular morphometric parameters in colorectal cancer, difficult to achieve through conventional immunohistochemistry, by using the confocal laser endomicroscopy method. Fresh biopsies from tumor and normal tissue were collected during colonoscopy from five patients with T3 colorectal carcinoma without metastasis and were marked with fluorescently labeled anti-CD31 antibodies. A series of optical slices spanning 250 µm inside the tissue were immediately collected for each sample using a confocal laser endomicroscope. All measurements were expressed as the mean ± standard error. The mean diameter of tumor vessels was significantly larger than the normal vessels (9.46±0.4 µm vs. 7.60±0.3 µm, p = 0.0166). The vessel density was also significantly higher in the cancer vs. normal tissue samples (5541.05±262.81 vs. 3755.79±194.96 vessels/mm3, p = 0.0006). These results were confirmed by immunohistochemistry. In addition, the tortuosity index and vessel lengths were not significantly different (1.05±0.016 and 28.30±3.27 µm in normal tissue, vs. 1.07±0.008 and 26.49±3.18 µm in tumor tissue respectively, p = 0.5357 and p = 0.7033). The daughter/mother ratio (ratio of the sum of the squares of daughter vessel radii over the square of the mother vessel radius) was 1.15±0.09 in normal tissue, and 1.21±0.08 in tumor tissue (p = 0.6531). The confocal laser endomicroscopy is feasible for measuring more vascular parameters from fresh tumor biopsies than conventional immunohistochemistry alone. Provided new contrast agents will be clinically available, future in vivo use of CLE could lead to identification of novel biomarkers based on the morphometric characteristics of tumor vasculature.

Microscopic imaging in endoscopy: endomicroscopy and endocytoscopy

Performing real-time microscopy has been a vision of endoscopists since the very early phases of gastrointestinal endoscopy. Confocal endomicroscopy, an adaption of confocal laser scanning microscopy, and endocytoscopy, an adaption of white-light microscopy, have been introduced into the endoscopic armamentarium in the past decade. Both techniques yield on-site histological information. Multiple trials have demonstrated the ability of gastroenterologists to obtain and interpret microscopic images from the upper and lower gastrointestinal tract, and also the hepatobiliary-pancreatic system, during endoscopy. Such microscopic information has been successfully used in expert hands to minimize sampling error by 'smart', microscopically targeted biopsies and to guide endoscopic interventions. However, endomicroscopy is also unique in its ability to dynamically visualize cellular processes in their native environment free of artefacts. This ability enables fundamental insights into mechanisms of human diseases in clinical and translational science.

Confocal Laser Endomicroscopy: Applications in Clinical and Translational Science—A Comprehensive Review

Confocal laser endomicroscopy (CLE) is a novel tool in the endoscopist’s armamentarium. It allows on-site histological information. The ability of gastroenterologists to interpret such microscopic information has been demonstrated in multiple studies from the upper and lower gastrointestinal tract. Recently, the field of application has expanded to provide hepatobiliary and intra-abdominal CLE imaging. CLE allows “smart,” targeted biopsies and is able to guide endoscopic interventions. But CLE is also translational in its approach and permits functional imaging that significantly impacts on our understanding of gastrointestinal diseases. Molecular imaging with CLE allows detection and characterization of lesions and may even be used for prediction of response to targeted therapy. This paper provides a comprehensive review over current applications of CLE in clinical applications and translational science.

Confocal laser endomicroscopy for the morphometric evaluation of microvessels in human colorectal cancer using targeted anti-CD31 antibodies

INTRODUCTION

Numerous anti-angiogenic agents are currently developed to limit tumor growth and metastasis. While these drugs offer hope for cancer patients, their transient effect on tumor vasculature is difficult to assess in clinical settings. Confocal laser endomicroscopy (CLE) is a novel endoscopic imaging technology that enables histological examination of the gastrointestinal mucosa. The aim of the present study was to evaluate the feasibility of using CLE to image the vascular network in fresh biopsies of human colorectal tissue. For this purpose we have imaged normal and malignant biopsy tissue samples and compared the vascular network parameters obtained with CLE with established histopathology techniques.

MATERIALS AND METHODS

Fresh non-fixed biopsy samples of both normal and malignant colorectal mucosa were stained with fluorescently labeled anti-CD31 antibodies and imaged by CLE using a dedicated endomicroscopy system. Corresponding biopsy samples underwent immunohistochemical staining for CD31, assessing the microvessel density (MVD) and vascular areas for comparison with CLE data, which were measured offline using specific software.

RESULTS

The vessels were imaged by CLE in both normal and tumor samples. The average diameter of normal vessels was 8.5±0.9 µm whereas in tumor samples it was 13.5±0.7 µm (p = 0.0049). Vascular density was 188.7±24.9 vessels/mm(2) in the normal tissue vs. 242.4±16.1 vessels/mm(2) in the colorectal cancer samples (p = 0.1201). In the immunohistochemistry samples, the MVD was 211.2±42.9/mm(2) and 351.3±39.6/mm(2) for normal and malignant mucosa, respectively. The vascular area was 2.9±0.5% of total tissue area for the normal mucosa and 8.5±2.1% for primary colorectal cancer tissue.

CONCLUSION

Selective imaging of blood vessels with CLE is feasible in normal and tumor colorectal tissue by using fluorescently labeled antibodies targeted against an endothelial marker. The method could be translated into the clinical setting for monitoring of anti-angiogenic therapy.

Endomicroscopy and cancer: a new approach to the visualization of neoangiogenesis

Probe-based Confocal Laser Endomicroscopy (pCLE) is a novel imaging technique for gastrointestinal endoscopy providing in vivo microscopy at subcellular resolution. It offers the possibility to analyze neoangiogenesis and vessel density in vivo. Angiogenetic switch is essential in cancer progression. Aim of the paper was to review the use of this imaging tool to analyze colorectal and gastric cancers vascularization in vivo. The aim is to provide the possibility of combining diagnostic evidences with vascularization and molecular profile to evaluate the efficacy of an antiangiogenic treatment in association with conventional therapy. pCLE can be considered a revolutionary method for real-time assessment of changes in vascularization pattern in this tumors and it may open the possibility to address the use of anti-angiogenic therapy in order to improve the outcome of the treatment.

Direct visualization of indeterminate pancreaticobiliary strictures with probe-based confocal laser endomicroscopy: a multicenter experience

BACKGROUND

Because of the low sensitivity of current ERCP-guided tissue sampling methods, management of patients with indeterminate pancreaticobiliary strictures is a challenge. Probe-based confocal laser endomicroscopy (pCLE) enables real-time microscopic visualization of strictures during an ongoing ERCP.

OBJECTIVE

To document the utility, performance, and accuracy of real-time pCLE diagnosis compared with histopathology.

DESIGN

Prospective observational study within the framework of a multicenter registry.

SETTING

Five academic centers.

PATIENTS

This study involved 102 patients with indeterminate pancreaticobiliary strictures.

INTERVENTION

Clinical information, ERCP findings, tissue sampling results, and pCLE videos were collected prospectively. Investigators were asked to provide a presumptive diagnosis based on pCLE during the procedure before pathology results were available. All patients received at least 30 days of follow-up until definitive diagnosis of malignancy was established or 1-year follow-up if index tissue sampling was benign.

MAIN OUTCOME MEASUREMENTS

Diagnostic accuracy, sensitivity, specificity of ERCP-guided pCLE compared with ERCP with tissue acquisition.

RESULTS

There were no pCLE-related adverse events in the study. We were able to evaluate 89 patients, of whom 40 were proven to have cancer. The sensitivity, specificity, positive-predictive value, and negative-predictive value of pCLE for detecting cancerous strictures were 98%, 67%, 71%, and 97%, respectively, compared with 45%, 100%, 100%, and 69% for index pathology. This resulted in an overall accuracy of 81% for pCLE compared with 75% for index pathology. Accuracy for combination of ERCP and pCLE was significantly higher compared with ERCP with tissue acquisition (90% vs 73%; P = .001).

LIMITATIONS

Investigators had access to all relevant clinical information, which may have biased the predictive characteristics of pCLE.

CONCLUSION

Probe-based CLE provides reliable microscopic examination and has excellent sensitivity and negative predictive value. The significantly higher accuracy of ERCP and pCLE compared with ERCP with tissue acquisition may support supplementing ERCP with pCLE.

Ultrasound-mediated optical tomography: a review of current methods

Ultrasound-mediated optical tomography (UOT) is a hybrid technique that is able to combine the high penetration depth and high spatial resolution of ultrasound imaging to overcome the limits imposed by optical scattering for deep tissue optical sensing and imaging. It has been proposed as a method to detect blood concentrations, oxygenation and metabolism at depth in tissue for the detection of vascularized tumours or the presence of absorbing or scattering contrast agents. In this paper, the basic principles of the method are outlined and methods for simulating the UOT signal are described. The main detection methods are then summarized with a discussion of the advantages and disadvantages of each. The recent focus on increasing the weak UOT signal through the use of the acoustic radiation force is explained, together with a summary of our results showing sensitivity to the mechanical shear stiffness and optical absorption properties of tissue-mimicking phantoms.

Confocal laser endomicroscopy in gastrointestinal diseases

Confocal laser endomicroscopy (CLE) is a novel endoscopic technique permitting in vivo microscopy (optical biopsies) of the gastrointestinal mucosa. CLE has been studied in a multitude of diseases of the upper and lower gastrointestinal tract, including Barrett's esophagus, gastric inflammation and cancer, celiac disease, colorectal adenoma and carcinoma, and inflammatory bowel diseases. CLE has recently evolved and been studied for bile duct and liver imaging. CLE has shown overall high accuracy and enabled smart, targeted biopsies rather than untargeted sampling. Furthermore, the availability of real time microscopic information during endoscopy has immediate impact on therapeutic decisions and guides endoscopic interventions. CLE is also a unique tool for observation of (patho-)physiologic events in their natural environment (functional imaging) and has been linked to molecular imaging of gastrointestinal neoplasia in vivo, thereby broadening our understanding of mucosal pathology in clinical and basic science.

Advances in endoscopic imaging of colorectal neoplasia

Colon cancer screening is arguably the most important activity performed by gastroenterologists. Recent decreases in rates of death from colorectal cancer indicate that screening methods such as colonoscopy have a positive impact. There is still room for improvement, however, particularly in prevention of right-sided colon cancer. Practice issues, such as making colonoscopy more comfortable, safer, and less costly, are keys to continued success in cancer prevention. Colonoscopy techniques, technologies, and quality control measures have advanced to improve detection, classification, and removal of early neoplasias. In particular, slow, careful inspection of the colon by gastroenterologists who have been trained in lesion recognition has improved rates of detection of polypoid and flat neoplasias. Image enhancement methods such as chromoendoscopy have greatly improved neoplasia detection in patients with chronic colitis, but are not widely used because they are perceived as inconvenient. More convenient methods, such as "digital" chromoendoscopy, show promise but have had mixed results. Ultra-high magnification systems, including optical magnification and confocal endomicroscopy, can be used during the colonoscopy examination to evaluate small polyps, allowing physicians to make immediate diagnoses and decisions about whether to remove polyps. In patients with inflammatory bowel disease, improved imaging techniques could eliminate the needs for analysis of randomly selected biopsy samples and resection of all (neoplastic and non-neoplastic) polyps. It is important to maintain high standards of quality for colonoscopy examination, detection, and removal of high-risk lesions, as well as to make colon cancer screening more widely accepted and affordable for the entire at-risk population.

The potential of biophotonic techniques in stem cell tracking and monitoring of tissue regeneration applied to cardiac stem cell therapy

The use of injected stem cells, leading to regeneration of ischemic heart tissue, for example, following coronary artery occlusion, has emerged as a major new option for managing 'heart attack' patients. While some clinical trials have been encouraging, there have also been failures and there is little understanding of the multiplicity of factors that lead to the outcome. In this overview paper, the opportunities and challenges in applying biophotonic techniques to regenerative medicine, exemplified by the challenge of stem cell therapy of ischemic heart disease, are considered. The focus is on optical imaging to track stem cell distribution and fate, and optical spectroscopies and/or imaging to monitor the structural remodeling of the tissue and the resulting functional changes. The scientific, technological, and logistics issues involved in moving some of these techniques from pre-clinical research mode ultimately into the clinic are also highlighted.

Confocal endomicroscopy

The preoperative diagnosis of biliary neoplasms is associated with a low sensitivity. To overcome this limitation, probe-based confocal laser endomicroscopy was further developed to enable in vivo microscopic imaging, with confocal miniprobes further miniaturized to such an extent to enable their use even via the instrumentation channel of cholangioscopes. The current data available suggest that this new technology represents a promising approach for further differentiation of strictures and stenosis in the biliary, and perhaps also pancreatic system. Nevertheless, those results are based on a limited number of patients; further studies involving more patients examined at various centers are necessary and already under way to prove the true clinical importance of this new imaging modality.

Fibered confocal microscopy of bladder tumors: an ex vivo study

BACKGROUND AND PURPOSE

The inadequacy of white-light cystoscopy to detect flat bladder tumors is well recognized. Great interest exists in developing other imaging technologies to augment or supplant conventional cystoscopy. Fibered confocal microscopy offers the promise of providing in vivo histopathologic information to help distinguish malignant from benign bladder lesions. We report the initial use of this technology to visualize tumors in the human bladder.

MATERIALS AND METHODS

We performed ex vivo fibered confocal imaging of fresh radical cystectomy specimens using the Mauna Kea Technologies Cellvizio system. The findings were compared with results from standard histopathology.

RESULTS

The bladders of four patients were imaged using the fibered confocal microscope. Normal and neoplastic urothelium manifested differences in cellular and vascular density.

CONCLUSION

This study demonstrates the feasibility of using fibered confocal microscopy to detect histologic differences between normal and neoplastic urothelium, and establishes a foundation for the use of fiber-based confocal microscopy in clinical studies.

Confocal endomicroscopy

PURPOSE OF REVIEW

Confocal laser endomicroscopy is an emerging field of endoscopic imaging allowing gastroenterologists to obtain in-vivo histology of the gastrointestinal mucosa. The present review will address the more recent advances in confocal laser endomicroscopy and discuss its future.

RECENT FINDINGS

Interest in confocal laser endomicroscopy and in-vivo diagnosis of gastrointestinal disorders has increased in the last few years. Confocal laser endomicroscopy can localize intraepithelial neoplasia in chronic ulcerative colitis and enable 'smarter' mucosal biopsy when combined with chromoendoscopy. Confocal laser endomicroscopy may accurately diagnose neoplasia in the esophagus, stomach, colon, and bile duct. Moreover, in-vivo visualization of morphologic epithelial abnormalities, such as intraepithelial bacteria and 'gaps in the gut', may increase our understanding of the possible pathogenic mechanisms of disease. Fluorescent peptide markers that target neoplasia are also being developed as a complementary approach to visualization of in-vivo histopathology.

SUMMARY

Confocal endomicroscopy is a developing area of gastrointestinal endoscopy with expanding clinical and research applications. The present review focuses on recent advances in confocal endomicroscopy.