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

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.

High-throughput omics technologies in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal disease. Elucidation of the pathogenic mechanisms of IBD requires high-throughput technologies (HTTs) to effectively obtain and analyze large amounts of data. Recently, HTTs have been widely used in IBD, including genomics, transcriptomics, proteomics, microbiomics, metabolomics and single-cell sequencing. When combined with endoscopy, the application of these technologies can provide an in-depth understanding on the alterations of intestinal microbe diversity and abundance, the abnormalities of signaling pathway-mediated immune responses and functionality, and the evaluation of therapeutic effects, improving the accuracy of early diagnosis and treatment of IBD. This review comprehensively summarizes the development and advancement of HTTs, and also highlights the challenges and future directions of these technologies in IBD research. Although HTTs have made striking breakthrough in IBD, more standardized methods and large-scale dataset processing are still needed to achieve the goal of personalized medicine.

In-Depth Assessment of Endoscopic Remission in Inflammatory Bowel Disease Treated by Anti-TNF or Vedolizumab

BACKGROUND AND AIMS

Confocal endomicroscopy is a technique allowing the in vivo assessment of the superficial layers of the mucosa. Preliminary studies have already suggested its added value in the assessment of endoscopic remission in inflammatory bowel disease. However, most of these studies were performed on patients still having incomplete mucosal healing. Our aim was to disclose persisting endomicroscopic anomalies in patients with full endoscopic remission and to compare them between vedolizumab- and anti-tumor necrosis factor-treated patients.

METHODS

We screened patients with Crohn's disease (CD) or ulcerative colitis (UC) treated for more than 6 months with biologic therapy, and being in steroid-free clinical and biological remission. White light endoscopy and probe-based confocal laser endomicroscopy (pCLE) analysis were performed in the ileum, right colon, transverse colon, left colon, and rectum. Full endoscopic remission was defined by a Mayo endoscopic score of 0 in UC and no remaining ulcer or erosion in CD. Patients were prospectively followed up and clinical relapses were recorded.

RESULTS

Seventy-two CD and UC patients treated by biologic therapy and in clinical and biological remission were screened. A total of 37 were also in full endoscopic remission and were included in our study; 183 intestinal segments were analyzed. We found residual pCLE anomalies in most of the patients. These anomalies were not significantly associated with any demographic or clinical characteristic including the treatment received, nor were they associated with histological parameters, levels of C-reactive protein or fecal calprotectin. Among the 37 patients, 7 (18.9%) relapsed over a median follow-up of 33.7 months. The risk of relapse was not associated with any clinical, biological, histologic, or pCLE feature at baseline.

CONCLUSION

Despite endoscopic, biological, and even histological remission, we found a high prevalence of endomicroscopic abnormalities, which were not different between anti-tumor necrosis factor- and vedolizumab-treated patients. The clinical significance of these anomalies remains to be clarified.

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.

Computer-Aided Imaging Analysis of Probe-Based Confocal Laser Endomicroscopy With Molecular Labeling and Gene Expression Identifies Markers of Response to Biological Therapy in IBD Patients: The Endo-Omics Study

BACKGROUND

We aimed to predict response to biologics in inflammatory bowel disease (IBD) using computerized image analysis of probe confocal laser endomicroscopy (pCLE) in vivo and assess the binding of fluorescent-labeled biologics ex vivo. Additionally, we investigated genes predictive of anti-tumor necrosis factor (TNF) response.

METHODS

Twenty-nine patients (15 with Crohn's disease [CD], 14 with ulcerative colitis [UC]) underwent colonoscopy with pCLE before and 12 to 14 weeks after starting anti-TNF or anti-integrin α4β7 therapy. Biopsies were taken for fluorescein isothiocyanate-labeled infliximab and vedolizumab staining and gene expression analysis. Computer-aided quantitative image analysis of pCLE was performed. Differentially expressed genes predictive of response were determined and validated in a public cohort.

RESULTS

In vivo, vessel tortuosity, crypt morphology, and fluorescein leakage predicted response in UC (area under the receiver-operating characteristic curve [AUROC], 0.93; accuracy 85%, positive predictive value [PPV] 89%; negative predictive value [NPV] 75%) and CD (AUROC, 0.79; accuracy 80%; PPV 75%; NPV 83%) patients. Ex vivo, increased binding of labeled biologic at baseline predicted response in UC (UC) (AUROC, 83%; accuracy 77%; PPV 89%; NPV 50%) but not in Crohn's disease (AUROC 58%). A total of 325 differentially expressed genes distinguished responders from nonresponders, 86 of which fell within the most enriched pathways. A panel including ACTN1, CXCL6, LAMA4, EMILIN1, CRIP2, CXCL13, and MAPKAPK2 showed good prediction of anti-TNF response (AUROC >0.7).

CONCLUSIONS

Higher mucosal binding of the drug target is associated with response to therapy in UC. In vivo, mucosal and microvascular changes detected by pCLE are associated with response to biologics in inflammatory bowel disease. Anti-TNF-responsive UC patients have a less inflamed and fibrotic state pretreatment. Chemotactic pathways involving CXCL6 or CXCL13 may be novel targets for therapy in nonresponders.

ZnUMBA - a live imaging method to detect local barrier breaches

Epithelial barrier function is commonly analyzed using transepithelial electrical resistance, which measures ion flux across a monolayer, or by adding traceable macromolecules and monitoring their passage across the monolayer. Although these methods measure changes in global barrier function, they lack the sensitivity needed to detect local or transient barrier breaches, and they do not reveal the location of barrier leaks. Therefore, we previously developed a method that we named the zinc-based ultrasensitive microscopic barrier assay (ZnUMBA), which overcomes these limitations, allowing for detection of local tight junction leaks with high spatiotemporal resolution. Here, we present expanded applications for ZnUMBA. ZnUMBA can be used in Xenopus embryos to measure the dynamics of barrier restoration and actin accumulation following laser injury. ZnUMBA can also be effectively utilized in developing zebrafish embryos as well as cultured monolayers of Madin-Darby canine kidney (MDCK) II epithelial cells. ZnUMBA is a powerful and flexible method that, with minimal optimization, can be applied to multiple systems to measure dynamic changes in barrier function with spatiotemporal precision.

Impaired Intestinal Permeability Assessed by Confocal Laser Endomicroscopy-A New Potential Therapeutic Target in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD) represent a global phenomenon, with a continuously rising prevalence. The strategies concerning IBD management are progressing from clinical monitorization to a targeted approach, and current therapies strive to reduce microscopic mucosal inflammation and stimulate repair of the epithelial barrier function. Intestinal permeability has recently been receiving increased attention, as evidence suggests that it could be related to disease activity in IBD. However, most investigations do not successfully provide adequate information regarding the morphological integrity of the intestinal barrier. In this review, we discuss the advantages of confocal laser endomicroscopy (CLE), which allows in vivo visualization of histological abnormalities and targeted optical biopsies in the setting of IBD. Additionally, CLE has been used to assess vascular permeability and epithelial barrier function that could correlate with prolonged clinical remission, increased resection-free survival, and lower hospitalization rates. Moreover, the dynamic evaluation of the functional characteristics of the intestinal barrier presents an advantage over the endoscopic examination as it has the potential to select patients at risk of relapses. Along with mucosal healing, histological or transmural remission, the recovery of the intestinal barrier function emerges as a possible target that could be included in the future therapeutic strategies for IBD.

Confocal laser endomicroscopy in gastro-intestinal endoscopy: technical aspects and clinical applications

Confocal laser endomicroscopy (CLE) is an advanced endoscopic imaging technology that provides a magnified, cellular level view of gastrointestinal epithelia. In conjunction with topical or intravenous fluorescent dyes, CLE allows for an "optical biopsy" for real-time diagnosis. Two different CLE system have been used in clinical endoscopy, probe-based CLE (pCLE) and endoscope-based CLE (eCLE). Using pCLE, the device can be delivered: (I) into the luminal gastrointestinal tract through the working channel of standard endoscopes; (II) into extraluminal cystic and solid parenchymal lesions through an endoscopic ultrasound (EUS) needle; or (III) into the biliary system through an endoscopic retrograde cholangiopancreatography (ERCP) accessory channel. With eCLE, the probe is directly integrated into the tip of a conventional endoscope, however, these endoscopes are no longer commercially available. CLE has moderate to high diagnostic accuracy for neoplastic and inflammatory conditions through the gastrointestinal tract including: oesophageal, gastric and colonic neoplasia, pancreatic cysts and solid lesions, malignant pancreatobiliary strictures and inflammatory bowel disease. Some studies have demonstrated the diagnostic benefit of CLE imaging when combined with either conventional white light endoscopy or advanced imaging technologies. Therefore, optical biopsies using CLE can resolve diagnostic dilemmas in some cases where conventional imaging fails to achieve conclusive results. CLE could also reduce the requirement for extensive tissue sampling during surveillance procedures. In the future, CLE in combination with molecular probes, could allow for the molecular characterization of diseases and assess response to targeted therapy. However, the narrow field of view, high capital costs and specialized operator training requirements remain the main limitations. Future multi-center, randomized trials with a focus on conventional diagnostic applications, cost-effectiveness and standardized training will be required for definitive evidence. The objective of this review is to evaluate the technical aspects and current applications of CLE in patients with gastrointestinal and pancreatobiliary diseases and discuss future directions for this technique.

Visualising and quantifying intestinal permeability -where do we stand

Intestinal permeability is getting more and more attention in gastrointestinal research. Although well recognized, its exact role in health and disease is yet to be defined. There are many methods of quantifying intestinal permeability, but most of them fail to deliver tangible information about the morphological integrity of the intestinal barrier. In this review we aim to describe imaging options for the assessment of intestinal barrier integrity and their potential relevance for clinical practice. Our focus is on confocal laser endomicroscopy, which is at this time the only method for visualizing not only functional but also morphological aspects of the gut barrier in vivo.

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.

Intracolic ultrasound molecular imaging: a novel method for assessing colonic tumor necrosis factor-α expression in inflammatory bowel disease

BACKGROUND

While anti-tumor necrosis factor alpha (TNF-α) therapy has been proven effective in inflammatory bowel disease (IBD), approximately 40% of patients lose the response. Transmembrane TNF-α (mTNF-α) expression in the intestinal mucosa is correlated with therapeutic efficacy, and quantification of mTNF-α expression is significant for predicting response. However, conventional intravenous application of microbubbles is unable to assess mTNF-α expression in intestinal mucosa. Herein, we proposed intracolic ultrasound molecular imaging with TNF-α-targeted microbubbles (MBTNF-α) to quantitatively detect mTNF-α expression in the intestinal mucosa.

METHODS

MBTNF-α was synthesized via a biotin-streptavidin bridging method. TNF-α-targeted ultrasound imaging was performed by intracolic application of MBTNF-α to detect mTNF-α expression in surgical specimens from a murine model and patients with IBD. Linear regression analyses were performed to confirm the accuracy of quantitative targeted ultrasound imaging.

RESULTS

On quantitative TNF-α-targeted ultrasound images, a greater signal intensity was observed in the mouse colons with colitis ([1.96 ± 0.45] × 106 a.u.) compared to that of the controls ([0.56 ± 0.21] × 106 a.u., P < 0.001). Targeted US signal intensities and inflammatory lesions were topographically coupled in mouse colons. Linear regression analyses in specimens of mice and patients demonstrated significant correlations between the targeted ultrasound signal intensity and mTNF-α expression (both P < 0.001). Furthermore, TNF-α-targeted ultrasound imaging qualitatively distinguished the varying inflammatory severity in intestinal specimens from IBD patients.

CONCLUSION

Intracolic ultrasound molecular imaging with MBTNF-α enables quantitative assessment of mTNF-α expression. It may be a potential tool for facilitating the implementation of personalized medicine in IBD.

Diagnosis of visceral pleural invasion using confocal laser endomicroscopy during lung cancer surgery

Background

Visceral pleural invasion (VPI) in lung cancer is a significant prognostic factor; however, it is difficult to diagnose preoperatively or intraoperatively. In this study, we examined the possibility of intraoperative diagnosis of VPI using confocal laser endomicroscopy (CLE).

Methods

Among patients with primary lung cancer who underwent surgery between April 2018 and August 2019, those in whom the tumor was in contact with the pleura on chest computed tomography and whose pleural changes were intraoperatively confirmed were enrolled in this study. In the 35 patients who underwent lung resection (6 cases with visceral pleural infiltration), the area where pleural change was noted was observed and a short video was recorded using CLE. Based on the video images, three evaluators determined the defect ratio (0%, 25%, 50%, 75%, and 100%) of the autofluorescence-positive structure. The area under the receiver operating characteristic curve was used to evaluate the diagnostic performance for VPI. In 15 cases (3 cases with VPI), a validation study was performed for intraoperative VPI according to the cutoff value of the defect ratio of the autofluorescence-positive structure.

Results

The areas under the receiver operating characteristic curve for the defect ratio of the autofluorescence-positive structure were 0.86–0.91 for the three readers. Using defect ratio of autofluorescence-positive structure cutoff of ≥50% as predictor of VPI, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 83.3–100.0%, 57.7–73.1%, 35.3–41.7%, 95.0–100.0%, and 75.0–78.1%, respectively, for the three readers. In the validation study, the sensitivity was 100%, the specificity was 83.3%, and the diagnostic accuracy rate was 86.7%.

Conclusions

The diagnosis of VPI through CLE is simple, non-invasive, and has high diagnostic accuracy rates. This method may be applicable for determining surgical procedures.

Clinical relevance of intestinal barrier dysfunction in common gastrointestinal diseases

The intestinal barrier is a complex and well-controlled physiological construct designed to separate luminal contents from the bowel wall. In this review, we focus on the intestinal barrier’s relationship with the host’s immune system interaction and the external environment, specifically the microbiome. The bowel allows the host to obtain nutrients vital to survival while protecting itself from harmful pathogens, luminal antigens, or other pro-inflammatory factors. Control over barrier function and the luminal milieu is maintained at the biochemical, cellular, and immunological level. However, disruption to this highly regulated environment can cause disease. Recent advances to the field have progressed the mechanistic understanding of compromised intestinal barrier function in the context of gastrointestinal pathology. There are numerous examples where bowel barrier dysfunction and the resulting interaction between the microbiome and the immune system has disease-triggering consequences. The purpose of this review is to summarize the clinical relevance of intestinal barrier dysfunction in common gastrointestinal and related diseases. This may help highlight the importance of restoring barrier function as a therapeutic mechanism of action in gastrointestinal pathology.

SAGES TAVAC safety and efficacy analysis confocal laser endomicroscopy

BACKGROUND

Confocal laser endomicroscopy (CLE) is a novel endoscopic adjunct that allows real-time in vivo histological examination of mucosal surfaces. By using intravenous or topical fluorescent agents, CLE highlights certain mucosal elements that facilitate an optical biopsy in real time. CLE technology has been used in different organ systems including the gastrointestinal tract. There has been numerous studies evaluating this technology in gastrointestinal endoscopy, our aim was to evaluate the safety, value, and efficacy of this technology in the gastrointestinal tract.

METHODS

The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) Technology and Value Assessment Committee (TAVAC) performed a PubMed/Medline database search of clinical studies involving CLE in May of 2018. The literature search used combinations of the keywords: confocal laser endomicroscopy, pCLE, Cellvizio, in vivo microscopy, optical histology, advanced endoscopic imaging, and optical diagnosis. Bibliographies of key references were searched for relevant studies not covered by the PubMed search. Case reports and small case series were excluded. The manufacturer's website was also used to identify key references. The United States Food and Drug Administration (U.S. FDA) Manufacturer And User facility and Device Experience (MAUDE) database was searched for reports regarding the device malfunction or injuries.

RESULTS

The technology offers an excellent safety profile with rare adverse events related to the use of fluorescent agents. It has been shown to increase the detection of dysplastic Barrett's esophagus, gastric intraepithelial neoplasia/early gastric cancer, and dysplasia associated with inflammatory bowel disease when compared to standard screening protocols. It also aids in the differentiation and classification of colorectal polyps, indeterminate biliary strictures, and pancreatic cystic lesions.

CONCLUSIONS

CLE has an excellent safety profile. CLE can increase the diagnostic accuracy in a number of gastrointestinal pathologies.

Image computing for fibre-bundle endomicroscopy: A review

Endomicroscopy is an emerging imaging modality, that facilitates the acquisition of in vivo, in situ optical biopsies, assisting diagnostic and potentially therapeutic interventions. While there is a diverse and constantly expanding range of commercial and experimental optical biopsy platforms available, fibre-bundle endomicroscopy is currently the most widely used platform and is approved for clinical use in a range of clinical indications. Miniaturised, flexible fibre-bundles, guided through the working channel of endoscopes, needles and catheters, enable high-resolution imaging across a variety of organ systems. Yet, the nature of image acquisition though a fibre-bundle gives rise to several inherent characteristics and limitations necessitating novel and effective image pre- and post-processing algorithms, ranging from image formation, enhancement and mosaicing to pathology detection and quantification. This paper introduces the underlying technology and most prevalent clinical applications of fibre-bundle endomicroscopy, and provides a comprehensive, up-to-date, review of relevant image reconstruction, analysis and understanding/inference methodologies. Furthermore, current limitations as well as future challenges and opportunities in fibre-bundle endomicroscopy computing are identified and discussed.

Confocal Laser Endomicroscopy in the Evaluation of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, can be effectively monitored with the use of endoscopy. The additional application of small field imaging technology such as confocal laser endomicroscopy CLE during ongoing endoscopic evaluation has led to real-time visualization of mucosal abnormalities and thus in vivo histology. The endomicroscopy (CLE) can improve IBD endoscopic evaluation by identifying seemingly normal-appearing mucosa, assessing the function of the intestinal barrier of the epithelium and vascular permeability, and by characterizing any mucosal lesions, including dysplastic lesions. CLE used during conventional endoscopy could especially facilitate the evaluation of mucosal healing in IBD. In addition, future developments in molecular imaging in IBD may optimize therapeutic approaches by identifying mucosal targets for therapy and determining the reasons for lack of response to specific therapy or subsequent loss of the response.

Fluorescence-based tracing of transplanted intestinal epithelial cells using confocal laser endomicroscopy

Background

Intestinal stem cell transplantation has been shown to promote mucosal healing and to engender fully functional epithelium in experimental colitis. Hence, stem cell therapies may provide an innovative approach to accomplish mucosal healing in patients with debilitating conditions such as inflammatory bowel disease. However, an approach to label and trace transplanted cells, in order to assess engraftment efficiency and to monitor wound healing, is a key hurdle to overcome prior to initiating human studies. Genetic engineering is commonly employed in animal studies, but may be problematic in humans due to potential off-target and long-term adverse effects.

Methods

We investigated the applicability of a panel of fluorescent dyes and nanoparticles to label intestinal organoids for visualization using the clinically approved imaging modality, confocal laser endomicroscopy (CLE). Staining homogeneity, durability, cell viability, differentiation capacity, and organoid forming efficiency were evaluated, together with visualization of labeled organoids in vitro and ex vivo using CLE.

Results

5-Chloromethylfluorescein diacetate (CMFDA) proved to be suitable as it efficiently stained all organoids without transfer to unstained organoids in co-cultures. No noticeable adverse effects on viability, organoid growth, or stem cell differentiation capacity were observed, although single-cell reseeding revealed a dose-dependent reduction in organoid forming efficiency. Labeled organoids were easily identified in vitro using CLE for a duration of at least 3 days and could additionally be detected ex vivo following transplantation into murine experimental colitis.

Conclusions

It is highly feasible to use fluorescent dye-based labeling in combination with CLE to trace intestinal organoids following transplantation to confirm implantation at the intestinal target site.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1246-5) contains supplementary material, which is available to authorized users.

The Value of Confocal Laser Endoscopy in Assessing the Quality of Duodenal Ulcer Healing

BACKGROUND AND OBJECTIVE

Confocal laser endomicroscopy (CLE) is a novel endoscopic technique that can image cells and subcellular layers of the gastric mucosa in vivo. We aimed to investigate the value of CLE in assessing the quality of ulcer healing (QOUH) and preliminarily establish evaluation criteria.

MATERIALS AND METHODS

Patients with duodenal ulcers were enrolled. After duodenal ulcer healing, we compared the value of CLE and white light endoscopy (WLE) in assessing the QOUH by using the histopathological diagnosis as the gold standard. At the same time, immunohistochemistry was performed to examine the expressions of transforming growth factor β1 (TGF-β1) and fibroblast growth factor 2 (FGF-2) in normal and scar tissues.

RESULTS

In assessing the QOUH classified as poor, good, and excellent by the pathological classification, the sensitivity of WLE was 57.14%, 50%, and 47.06%, the specificity was 87.80%, 52.38%, and 81.58%, and the accuracy was 80.00%, 50.91%, and 70.91%, respectively. Meanwhile, the sensitivity of CLE was 73.33%, 85.19%, and 92.31%, the specificity was 95%, 85.71%, and 92.86%, and the accuracy was 89.09%, 85.45%, and 92.73%, respectively. The κ value for the correlation with pathological diagnosis grade was 0.38 for WLE vs. 0.74 for CLE. The assessment of the QOUH in the CLE image classification showed great improvement compared with that in the WLE image classification. The image classification of CLE was not associated with the immunohistochemical expression of TGF-β1 or FGF-2 according the Spearman rank correlation (P > 0.05).

CONCLUSION

Compared with WLE, CLE has a higher value in assessing the QOUH. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.

Papaverine adjuvant therapy for microcirculatory disturbance in severe ulcerative colitis complicated with CMV infection: a case report

Ulcerative colitis has hypercoagulable state and high risk of thrombosis; so mucosal disturbance of microcirculation may be mediate and amplify the inflammation of ulcerative colitis. A 56-year-old female patient was admitted in hospital for discontinuously mucous bloody stool for more than 1 year. Ulcerative colitis was determined after colonoscopy and pathologic examination. Mesalazine was effective during the year, but her symptoms recurred three times due to her bad compliance. One month before admission, the patient had severe recurrence after mesalazine withdrawal. At this time, the result of quantitative fluorescence PCR of colonic histic CMV-DNA was 1.6 × 10⁴ copies/mL positive, CMV colitis was accompanied. After 4 weeks of ganciclovir and 6 weeks of mesalazine usage and nutrition support, the symptoms of diarrhea and abdominal cramp did not improve; stool frequency was more than twenty times a day. Probe-based confocal laser endomicroscopy revealed local microcirculation disturbance. Papaverine 90-mg slow drip for at least 10 h a day was added. The symptoms dramatically disappeared after 3 days of papaverine treatment. The patient had yellow mushy stool 2–3 times a day. Pathological findings showed diffuse submucosal hemorrhage and transparent thrombosis in capillaries. Treatment of microcirculatory disturbance in severe UC is a promising adjuvant therapy. Confocal laser endomicroscopy may be an effective method for microcirculation judgment.

Multiscale imaging of colitis in mice using confocal laser endomicroscopy, light-sheet fluorescence microscopy, and magnetic resonance imaging

The objective of our study is to develop a multimodality approach by combining magnetic resonance imaging (MRI) and optical imaging methods to assess acute murine colitis at the macro- and microscopic level. In vivo MRI is used to measure the cross-sectional areas of colons at the macroscopic level. Dual-color confocal laser endomicroscopy (CLE) allows in vivo examination of the fluorescently labeled epithelial cells and microvessels in the mucosa with a spatial resolution of ∼1.4  μm during ongoing endoscopy. To further validate the structural changes of the colons in three-dimensions, ex vivo light-sheet fluorescence microscopy (LSFM) is applied for in-toto imaging of cleared colon sections. MRI, LSFM, and CLE findings are significantly correlated with histological scoring (p  <  0.01) and the inflammation-associated activity index (p  <  0.01). Our multimodality imaging technique permits visualization of mucosa in colitis at different scales, which can enhance our understanding of the pathogenesis of inflammatory bowel diseases.

Outcomes of vedolizumab therapy in patients with immune checkpoint inhibitor-induced colitis: a multi-center study

BACKGROUND

Immune-mediated diarrhea and colitis (IMDC) can limit immune checkpoint inhibitors (ICIs) treatment, which is efficacious for advanced malignancies. Steroids and infliximab are commonly used to treat it. These agents induce systemic immunosuppression, with its associated morbidity. We assessed clinical outcomes of vedolizumab as an alternative treatment for IMDC.

METHODS

We analyzed a retrospective case series of adults who had IMDC refractory to steroids and/or infliximab and received vedolizumab from 12/2016 through 04/2018.

RESULTS

Twenty-eight patients were included. The median time from ICI therapy to IMDC onset was 10 weeks. Fifteen patients (54%) had grade 2 and 13 (46%) had grade 3 or 4 IMDC. Mucosal ulceration was present in 8 patients (29%), and nonulcerative inflammation was present in 13 (46%). All patients had features of active histologic inflammation; 14 (50%) had features of chronicity, and 10 (36%) had features of microscopic colitis concurrently. The mean duration of steroid therapy was 96 days (standard deviation 74 days). Nine patients received infliximab in addition to steroids and their IMDC was refractory to it. Among these, the duration of steroid use was 131 days compared with 85 days in patients who did not receive infliximab. Likewise, patients who failed infliximab before vedolizumab had a clinical success rate of 67% compared to 95% for patients that did not receive infliximab. The median number of vedolizumab infusions was 3 (interquartile range 1-4). The mean duration of follow-up was 15 months. Twenty-four patients (86%) achieved and sustained clinical remission. Repeat endoscopic evaluation was performed in 17 patients. Endoscopic remission was attained in 7 (54%) of the 13 patients who had abnormal endoscopic findings initially; 5/17 patients (29%) reached histologic remission as well.

CONCLUSIONS

Vedolizumab can be appropriate for the treatment of steroid-refractory IMDC, with favorable outcomes and a good safety profile.

Molecular Pathophysiology of Epithelial Barrier Dysfunction in Inflammatory Bowel Diseases

Over the years, the scientific community has explored myriads of theories in search of the etiology and a cure for inflammatory bowel disease (IBD). The cumulative evidence has pointed to the key role of the intestinal barrier and the breakdown of these mechanisms in IBD. More and more scientists and clinicians are embracing the concept of the impaired intestinal epithelial barrier and its role in the pathogenesis and natural history of IBD. However, we are missing a key tool that bridges these scientific insights to clinical practice. Our goal is to overcome the limitations in understanding the molecular physiology of intestinal barrier function and develop a clinical tool to assess and quantify it. This review article explores the proteins in the intestinal tissue that are pivotal in regulating intestinal permeability. Understanding the molecular pathophysiology of impaired intestinal barrier function in IBD may lead to the development of a biochemical method of assessing intestinal tissue integrity which will have a significant impact on the development of novel therapies targeting the intestinal mucosa.

Endoscopic ultrasound guided needle-based confocal laser endomicroscopy in solid pancreatic masses - a prospective validation study

BACKGROUND AND STUDY AIMS

 Endoscopic ultrasound fine-needle aspiration (EUS-FNA) is a keystone in diagnosing and staging of pancreatic masses. Recently, a microfiber that can pass through a 19-gauge needle has been introduced for confocal laser endomicroscopy (nCLE). The aims of this study were to evaluate the diagnostic value and the reproducibility of nCLE criteria for solid malignant lesions.

PATIENTS AND METHODS

 This prospective dual-center study included patients with pancreatic masses suspicious of malignancy referred for EUS-FNA. Endomicroscopic imaging was performed under EUS-guidance until organ-specific structures were obtained. Afterwards, standard cytology was obtained and patients were followed for up to 12 months. All nCLE parameters included in former studies were correlated with the final diagnosis (dark lobular structures/normal acinar cells, dark cell aggregates > 40 µm, dilated irregular vessels with fluorescein leakage, fine white fibrous bands, small black cell movements, pseudoglandular structures). Finally, three CLE novices and three CLE experts assessed the unedited movies from all patients.

RESULTS

 Twenty-eight patients were enrolled in the study. A final diagnosis was obtained in 24 patients (86 %). One patient (3 %) died before a diagnosis was obtained, while 3 were lost to follow-up (11 %). In 18/24 patients (74 %) the diagnosis was malignant. The mean sensitivity, specificity, and accuracy for the nCLE parameters ranged from 19 - 93 %, 0 - 56 %, 26 - 69 %, respectively. The inter-observer values ranged from κ = 0.20 - 0.41 for novices and κ = -0.02 - 0.38 for experts.

CONCLUSIONS

 The diagnostic value of nCLE in solid pancreatic masses is questionable and the inter-observer agreement for both novices and CLE experts appears limited.

Endomicroscopy and Molecular Tools to Evaluate Inflammatory Bowel Disease

Endoscopy is an essential tool for effective care of patients with inflammatory bowel disease (IBD), including Crohn disease and ulcerative colitis. The newest endoscopic small-field imaging technologies with confocal endomicroscopy have allowed real-time imaging of gastrointestinal mucosal during ongoing endoscopic evaluation and in vivo histology. Thus, endomicroscopy has a potential to further enhance the endoscopic evaluation of IBD. Advances in molecular in vivo imaging in IBD may be used not only to better understand the pathophysiology of IBD but also to guide optimized therapy and thus to allow a personalized, new approach to the IBD management.

From bench to bedside: molecular imaging in inflammatory bowel diseases

PURPOSE OF REVIEW

Standard structural imaging procedures such as endoscopy, ultrasonography, or MRI are an integral part of the rational management of patients with inflammatory bowel diseases (IBDs). There is nevertheless the need for further refined imaging approaches that are able to overcome the limitations of currently used formats. The advent of molecular imaging modalities that allow real-time visualization of cellular processes not only in the preclinical setting but also in clinical trials has demonstrated its ability to improve current therapeutic strategies. The purpose of this review is to present and discuss advancements in the field of molecular imaging approaches in the IBD field.

RECENT FINDINGS

Recent preclinical and clinical studies have addressed the applicability of molecular imaging for improving the differentiation between benign and malignant mucosal alterations, increasing the detection of dysplastic intestinal lesions, and predicting individual responses to biological therapies.

SUMMARY

Molecular imaging in IBD represents an exciting and evolving field that has the potential to impact on current diagnostic and therapeutic algorithms in the treatment of IBD patients by analyzing and visualizing the molecular mechanisms that drive mucosal inflammation. It might enable us to base individualized therapeutic decisions on preceded molecular level analysis by suitable imaging modalities.

Advanced gastrointestinal endoscopic imaging for inflammatory bowel diseases

Gastrointestinal luminal endoscopy is of paramount importance for diagnosis, monitoring and dysplasia surveillance in patients with both, Crohn’s disease and ulcerative colitis. Moreover, with the recent recognition that mucosal healing is directly linked to the clinical outcome of patients with inflammatory bowel disorders, a growing demand exists for the precise, timely and detailed endoscopic assessment of superficial mucosal layer. Further, the novel field of molecular imaging has tremendously expanded the clinical utility and applications of modern endoscopy, now encompassing not only diagnosis, surveillance, and treatment but also the prediction of individual therapeutic responses. Within this review, we describe how novel endoscopic approaches and advanced endoscopic imaging methods such as high definition and high magnification endoscopy, dye-based and dye-less chromoendoscopy, confocal laser endomicroscopy, endocytoscopy and molecular imaging now allow for the precise and ultrastructural assessment of mucosal inflammation and describe the potential of these techniques for dysplasia detection.