Are we ready to use new endoscopic scores for ulcerative colitis?

For ulcerative colitis (UC), the variability in inflammatory activity along the colon poses a challenge in management. The focus on achieving endoscopic healing in UC is evident, where the UC Endoscopic Index of Severity and Mayo Endoscopic Subscore are commonly used for evaluation. However, these indices primarily consider the most severely affected region. Liu et al recent study validates the Toronto Inflammatory Bowel Disease Global Endoscopic Reporting (TIGER) score offering a comprehensive assessment of inflammatory activity across diverse segments of the colon and rectum and a reliable index correlating strongly with UC Endoscopic Index of Severity and moderately with Mayo Endoscopic Subscore (MES). Despite recommendation, certain aspects warrant further investigation. Fecal calprotectin, an intermediate target, correlates with TIGER and should be explored. Determining TIGER scores defining endoscopic remission and response, evaluating agreement with histological activity, and assessing inter-endoscopist agreement for TIGER require scrutiny. Exploring the correlation between TIGER and intestinal ultrasound, akin to MES, adds value.

Utility of Combined Use of Transabdominal Ultrasonography and Fecal Immunochemical Test Examinations in Ulcerative Colitis.

This study examined the utility of the combined use of transabdominal ultrasonography (TUS) and fecal immunochemical testing (FIT) to detect mucosal inflammation, vis-a-vis the Mayo endoscopic subscore (MES), in ulcerative colitis (UC). Sixty-three UC patients who underwent TUS and FIT were retrospectively enrolled. For TUS, the colon was divided into five segments, and the bowel wall thickness was measured and evaluated. The accuracy of FIT (> 100 ng/ml) in detecting mucosal inflammation (MES>0) was 0.93, whereas that of TUS (BWT>2 mm) in each segment was 0.84-0.97. The combined use of TUS and FIT may be helpful in noninvasive treatment strategies.

Endoscopic features of lymphoid follicles in the colonic mucosa using the image enhanced endoscopy and its association with colorectal adenoma.

BACKGROUND/AIM: Lymphoid follicles hyperplasia (LH) is sometimes observed in the normal colon as small, round, yellowish-white nodules. LH is associated with food hypersensitivity and bowel symptoms and histologically characterized as intense infiltration of lymphocytes or plasmacytes. It is suggested that LH represents inflammatory immune response in the colonic mucosa. We investigated the presence of LH in the normal colonic mucosa and its association with incidence of colorectal lesions including colorectal cancer, adenoma and hyperplastic polyp. PATIENTS/METHODS: 605 participants undergoing colonoscopy for various indications were enrolled. Presence of LH in the proximal colon (appendix, cecum and the ascending colon) was observed using the blue laser imaging (BLI) endoscopy, a new generation image enhanced endoscopy (IEE) system. LH was defined as well demarcated white nodules. Elevated LH with erythema was distinguished as LH severe. Association between presence of LH and occurrence of colorectal lesions was investigated. RESULTS: Prevalence of all colorectal lesions and adenoma were significantly lower in LH severe group compared to the LH negative group (P = 0.0008, 0.0009, respectively). Mean number of all colorectal lesions and adenoma were also lower in LH severe group compared to the LH negative group (P = 0.005, 0.003 respectively). The logistic regression with adjustment for gender and age demonstrated that presence of LH severe held significantly lower risk of all colorectal lesions (OR = 0.48, 95%CI = 0.27-0.86) and adenoma (OR = 0.47, 95%CI = 0.26-0.86). CONCLUSION: LH in the colonic mucosa visualized by IEE is useful endoscopic finding to predict risk of colorectal adenoma.

Early Intestinal Ultrasound Predicts Long-Term Endoscopic Response to Biologics in Ulcerative Colitis.

BACKGROUND AND AIMS: The Milan ultrasound criteria [MUC] is a validated score to assess endoscopic activity in ulcerative colitis [UC]. MUC > 6.2 detects Mayo endoscopic score [MES] > 1. In this study we evaluated the predictive value of MUC for biologic treatment response, using colonoscopy [CS] as a reference standard. METHODS: Consecutive UC patients starting biologic therapy were included, and underwent CS, IUS, clinical assessment and faecal calprotectin [FC] measurement at baseline and within 1 year. In addition, IUS, clinical and FC assessments were performed at week 12. The primary objective was to evaluate whether ultrasound improvement [MUC ≤ 6.2] at week 12 predicted endoscopic improvement at reassessment [MES ≤ 1]. Endoscopic remission was defined as MES = 0. RESULTS: Forty-nine patients were included [59% under infliximab, 29% under vedolizumab, 8% under adalimumab, 4% under ustekinumab]. MUC ≤ 6.2 at week 12 was the only independent predictor for MES ≤ 1 and MES = 0 at reassessment (odds ratio [OR] 5.80, p = 0.010; OR 10.41, p = 0.041; respectively). MUC ≤ 6.2 at week 12 showed a negative predictive value of 96% for detecting MES = 0. A ≥2 reduction of the MUC predicted MES = 0 (area under the curve [AUC] 0.816). MUC ≤ 4.3 was the most accurate cut-off value for MES = 0 [AUC 0.876]. Guyatt's responsiveness ratio for the MUC was 1.73 [>0.8]. CONCLUSION: MUC ≤ 6.2 at week 12 predicts long-term endoscopic response. MUC is accurate in monitoring treatment response and may be used in both clinical trials and routine practice.

Intestinal epithelial barrier integrity investigated by label-free techniques in ulcerative colitis patients.

The intestinal epithelial barrier, among other compartments such as the mucosal immune system, contributes to the maintenance of intestinal homeostasis. Therefore, any disturbance within the epithelial layer could lead to intestinal permeability and promote mucosal inflammation. Considering that disintegration of the intestinal epithelial barrier is a key element in the etiology of ulcerative colitis, further assessment of barrier integrity could contribute to a better understanding of the role of epithelial barrier defects in ulcerative colitis (UC), one major form of chronic inflammatory bowel disease. Herein, we employ fast, non-destructive, and label-free non-linear methods, namely coherent anti-Stokes Raman scattering (CARS), second harmonic generation (SHG), two-photon excited fluorescence (TPEF), and two-photon fluorescence lifetime imaging (2P-FLIM), to assess the morpho-chemical contributions leading to the dysfunction of the epithelial barrier. For the first time, the formation of epithelial barrier gaps was directly visualized, without sophisticated data analysis procedures, by the 3D analysis of the colonic mucosa from severely inflamed UC patients. The results were compared with histopathological and immunofluorescence images and validated using transmission electron microscopy (TEM) to indicate structural alterations of the apical junction complex as the underlying cause for the formation of the epithelial barrier gaps. Our findings suggest the potential advantage of non-linear multimodal imaging is to give precise, detailed, and direct visualization of the epithelial barrier in the gastrointestinal tract, which can be combined with a fiber probe for future endomicroscopy measurements during real-time in vivo imaging.

Feasibility and efficacy of endoscopic purse-string suture-assisted closure for mucosal defects induced by endoscopic manipulations.

BACKGROUND: Large or transmural defects induced by gastrointestinal endoscopic manipulations are difficult to close, although complete closure is recommended for better recovery. Endoscopic purse-string assisted suturing (EPSS) has been used in clinical practice and has proven to be an effective and safe technique for the closure of large mucosal defects. However, details regarding the efficacy of endoscopic pre-purse-string suture (P-EPSS) are unknown, especially that it offers several advantages over conventional EPSS (C-EPSS). AIM: To elucidate the outcomes of EPSS-assisted closure in different clinical situations, and evaluate the efficacy of P-EPSS. METHODS: This retrospective observational study included a total of 180 patients who underwent closure assisted by P-EPSS (n = 63) or C-EPSS (n = 117) between July 2014 and June 2020. The P-EPSS and C-EPSS groups were compared and the intergroup differences in aspects such as the lesion size, location, and mor-phology, incidence of complete closure, intraoperative perforation, and delayed adverse events were evaluated. Data on the features and clinical course of cases with adverse events were collected for further analysis. RESULTS: Patients with lesion size larger than 3 cm, lesions located at the fundus of stomach, or submucosal tumors originating from the deep mucosa were more likely to undergo P-EPSS-assisted closure. The P-EPSS group showed a sign-ificantly higher proportion of intraoperative perforation (56% vs 17%) and a much shorter procedure time (9.06 ± 6.14 min vs 14.84 ± 7.25 min). Among adverse events, the incidence of delayed perforation (5% vs 4%; P = 0.82) and delayed bleeding (3% vs 4%; P = 0.96) did not differ significantly between the groups. Multivariate analysis revealed that lesions with incomplete closure [odds ratio (OR) = 21.33; 95% confidence interval (CI): 5.45-83.45; P < 0.01] or size greater than 3 cm (OR = 3.14; 95%CI: 1.08-9.18; P = 0.039) showed a statistical tendency to result in an increase in delayed adverse events. CONCLUSION: The present study revealed that EPSS could achieve secure complete closure of mucosal defect. P-EPSS could shorten the procedure and yield complete closure of mucosal defects. Rather than closure-type selection, incomplete closure or lesion size larger than 3 cm were associated with worse outcomes.

Automated analysis of small intestinal lamina propria to distinguish normal, Celiac Disease, and Non-Celiac Duodenitis biopsy images.

BACKGROUND AND OBJECTIVE: Celiac Disease (CD) is characterized by gluten intolerance in genetically predisposed individuals. High disease prevalence, absence of a cure, and low diagnosis rates make this disease a public health problem. The diagnosis of CD predominantly relies on recognizing characteristic mucosal alterations of the small intestine, such as villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis. However, these changes are not entirely specific to CD and overlap with Non-Celiac Duodenitis (NCD) due to various etiologies. We investigated whether Artificial Intelligence (AI) models could assist in distinguishing normal, CD, and NCD (and unaffected individuals) based on the characteristics of small intestinal lamina propria (LP). METHODS: Our method was developed using a dataset comprising high magnification biopsy images of the duodenal LP compartment of CD patients with different clinical stages of CD, those with NCD, and individuals lacking an intestinal inflammatory disorder (controls). A pre-processing step was used to standardize and enhance the acquired images. RESULTS: For the normal controls versus CD use case, a Support Vector Machine (SVM) achieved an Accuracy (ACC) of 98.53%. For a second use case, we investigated the ability of the classification algorithm to differentiate between normal controls and NCD. In this use case, the SVM algorithm with linear kernel outperformed all the tested classifiers by achieving 98.55% ACC. CONCLUSIONS: To the best of our knowledge, this is the first study that documents automated differentiation between normal, NCD, and CD biopsy images. These findings are a stepping stone toward automated biopsy image analysis that can significantly benefit patients and healthcare providers.

Prevalence and Correlations of Gastrointestinal Symptoms With Endoscopic and Histologic Mucosal Healing in Crohn's Disease.

To characterize the associations between clinical disease activity with endoscopic and histologic (endohistologic) mucosal healing in Crohn's disease, we performed a secondary analysis of prospectively collected data on 424 ileocolonoscopies from 258 unique adults at a tertiary referral center from 2014 to 2021. One-third of patients (34%, 25/73) in endoscopic-histologic remission reported gastrointestinal symptoms. The 2-item patient-reported outcome measure for abdominal pain and stool frequency correlated weakly with endoscopic (Simple Endoscopic Score for Crohn's Disease; r = 0.17, 95% CI 0.08-0.26, P = 0.0003) and histologic disease activity (Global Histologic Disease Activity Score; r = 0.14, 95% CI 0.03-0.24, P = 0.015). Overall, gastrointestinal symptoms correlate poorly with endohistologic disease activity.

Endocytoscopy for assessing histologic inflammation in ulcerative colitis: development and prospective validation of the ELECT (ErLangen Endocytoscopy in ColiTis) score (with videos).

BACKGROUND AND AIMS: Apart from endoscopic healing as an established treatment goal in patients with inflammatory bowel disease (IBD), histologic remission is an emerging endpoint that might even better predict disease outcome, especially in ulcerative colitis (UC). Within this study, we aimed to evaluate whether endocytoscopy (EC) as an in vivo contact microscopy technology can accurately assess histologic inflammation and predict the further course of disease in UC patients. METHODS: Initially, a new and intuitive EC score reflecting the entire spectrum of microscopic disease activity in UC was consensually developed. Subsequently, this score was independently validated in 46 patients with UC who underwent close-meshed follow-up during which major adverse outcomes (MAOs; defined as disease flare, IBD-related hospitalization, IBD-related surgery, necessity for initiation or escalation therapy) were recorded. Results of EC grading of inflammatory activity were compared against 2 validated histologic scores in UC. Diagnostic performance of endoscopic remission under white-light endoscopy (Mayo Endoscopic Score and Ulcerative Colitis Endoscopic Index of Severity), EC, and histology were compared for the prediction of MAOs. RESULTS: Endocytoscopic assessment of inflammatory activity in UC based on the newly developed ErLangen Endocytoscopy in ColiTis score showed strong correlation with histopathologic scoring (Robarts Histopathology Index, r = .70; Nancy Histologic Index, r = .73) and was superior to white-light endoscopy for grading of microscopic disease activity, with a sensitivity of 88%, specificity of 95.2%, and area under the curve of .916. Furthermore, EC exhibited a high interobserver agreement for in vivo grading of microscopic inflammation and was comparably accurate as histopathology for forecasting the occurrence of MAOs in UC. CONCLUSIONS: Endocytoscopic grading of inflammatory activity along a newly developed scoring system enabled real-time histology in UC patients and better predicted clinical outcome in UC patients than endoscopic remission.

Possible Role of Image-Enhanced Endoscopy in the Evaluation of Mucosal Healing of Ulcerative Colitis.

BACKGROUND: Mucosal healing (MH) is recognized as a therapeutic target in ulcerative colitis (UC) because of evidence that it is associated with favorable clinical outcomes. Current endoscopic assessment of MH by conventional white-light endoscopy is subject to several important clinical issues including the subjective nature of assessment, intra- and interobserver variability, and persistent microscopic inflammation, even in mucosa it was observed as quiescent on conventional endoscopy. SUMMARY: Advances in image-enhancement technologies enable the provision of high-contrast images that emphasize the mucosal structures, blood vessel patterns, and color tones of the intestinal mucosa, and recently, several image-enhanced endoscopy (IEE) techniques have become available for the assessment of MH in UC. Narrow-band imaging and dual-red imaging facilitate visualization of mucosal vascular structures, which is useful for detecting minor inflammation and predicting relapse because of the capturing of information on incomplete vascular regeneration in patients with UC. Linked-color imaging (LCI) is optimized to emphasize the redness of the mucosa and blood vessels, and is superior for depicting subtle color changes arising from mucosal inflammation. LCI could possibly be used to stratify UC patients with MH on conventional endoscopy. Autofluorescence imaging and i-scan can also depict subtle histological changes underlying the healing of mucosa in UC, revealing them as simple color changes. KEY MESSAGES: Accumulating evidence suggests that IEE techniques could overcome current unmet needs in the endoscopic assessment of MH in UC and contribute to improving therapy based on treat-to-target strategies.

Beyond Neutrophils for Predicting Relapse and Remission in Ulcerative Colitis.

BACKGROUND AND AIMS: This study examines colonic histological features in ulcerative colitis [UC] in endoscopic remission to determine which cell types and biopsy sites best predict a patient's likelihood of remaining in remission. METHODS: This is a retrospective chart, endoscopy and histology review of 166 patients with UC in endoscopic remission followed in a single inflammatory bowel disease practice over a median of 6 years [range, 2-11 years]. Clinical remission was based on global physician assessment and colonoscopy reports, and clinical relapse on chart review. Histological features of previous injury and also number and location of plasma cells and eosinophils were assessed. We evaluated all of these features semi-quantitatively using a standard set of illustrations for the grade to maintain consistency. Multiple logistic regression and survival analyses were used to identify features associated with relapse. RESULTS: Clinical relapse occurred in 44 patients. Ulceration, especially in the left colon, was highly predictive of relapse. In the absence of acute inflammation of ulceration, the variables most predictive of relapse were increased plasma cells in the basal 20% of the lamina propria, and eosinophils in the left colon. The variable most predictive of persistent remission was the presence of intra-epithelial eosinophils whether in the surface epithelium or within crypts, especially in the right colon. Lamina propria eosinophils [grade > 2] throughout the colon predicted relapse. CONCLUSION: In the absence of neutrophils or ulceration, left-sided plasmacytosis in the basal 20% of the lamina propria and increased lamina propria eosinophils provide the best indicators of relapse in UC in clinical and endoscopic remission.

Association between Mucosal Healing and Lipid Profiles in Patients with Ulcerative Colitis: A Cross-Sectional Study.

INTRODUCTION: Recent meta-analysis showed that ulcerative colitis (UC) is a risk factor for cardiovascular disease (CVD). Dyslipidemia is a well-established risk factor for CVD. However, evidence regarding inflammatory bowel disease (IBD), including UC and lipid profiles, is limited. Additionally, no study has assessed the association between endoscopic activity and lipid profiles in patients with IBD. Therefore, we aimed to clarify the association between mucosal healing (MH) and lipid profiles in patients with UC. METHODS: A total of 221 Japanese patients with UC were enrolled in this analysis. Total cholesterol (T-chol), triglyceride (TG), and high-density lipoprotein cholesterol (HDL-C) were divided into tertiles (high, moderate, and low) based on the distributions, respectively. Self-administered questionnaire was used to obtain information regarding medication for dyslipidemia. Complete MH and MH are based on Mayo endoscopic subscore 0 and 0-1, respectively. RESULTS: The percentage of complete MH was 30.8%. In patients without medication for dyslipidemia, high HDL-C (>66 mg/dL) was significantly positively associated with complete MH (adjusted odds ratio [OR] 2.58, 95% CI: 1.04-6.64, p for trend = 0.037). In patients with nonproctitis, a positive association between HDL-C and complete MH was found (adjusted OR 3.54, 95% CI: 1.22-11.01, p for trend = 0.020). T-chol and TG were not associated with MH, regardless of medication for dyslipidemia. CONCLUSIONS: Complete MH was significantly positively associated with HDL-C in UC patients without medication for lipid. The disease extent might affect the association between complete MH and HDL-C.

Endoscopic mucosal resection-precutting vs conventional endoscopic mucosal resection for sessile colorectal polyps sized 10-20 mm.

BACKGROUND: The optimal method to remove sessile colorectal lesions sized 10-20 mm remains uncertain. Piecemeal and incomplete resection are major limitations in current practice, such as endoscopic mucosal resection (EMR) and cold or hot snare polypectomy. Recently, EMR with circumferential precutting (EMR-P) has emerged as an effective technique, but the quality of current evidence in comparative studies of conventional EMR (CEMR) and EMR-P is limited. AIM: To investigate whether EMR-P is superior to CEMR in removing sessile colorectal polyps. METHODS: This multicenter randomized controlled trial involved seven medical institutions in China. Patients with colorectal polyps sized 10-20 mm were enrolled and randomly assigned to undergo EMR-P or CEMR. EMR-P was performed following submucosal injection, and a circumferential mucosa incision (precutting) was conducted using a snare tip. Primary outcomes included a comparison of the rates of en bloc and R0 resection, defined as one-piece resection and one-piece resection with histologically assessed clear margins, respectively. RESULTS: A total of 110 patients in the EMR-P group and 110 patients in the CEMR group were finally evaluated. In the per-protocol analysis, the proportion of en bloc resections was 94.3% [95% confidence interval (CI): 88.2%-97.4%] in the EMR-P group and 86% (95%CI: 78.2%-91.3%) in the CEMR group (P = 0.041), while subgroup analysis showed that for lesions > 15 mm, EMR-P also resulted in a higher en bloc resection rate (92.0% vs 58.8% P = 0.029). The proportion of R0 resections was 81.1% (95%CI: 72.6%-87.4%) in the EMR-P group and 76.6% (95%CI: 68.8%-84.4%) in the CEMR group (P = 0.521). The EMR-P group showed a longer median procedure time (6.4 vs 3.0 min; P < 0.001). No significant difference was found in the proportion of patients with adverse events (EMR-P: 9.1%; CEMR: 6.4%; P = 0.449). CONCLUSION: In this study, EMR-P served as an alternative to CEMR for removing nonpedunculated colorectal polyps sized 10-20 mm, particularly polyps > 15 mm in diameter, with higher R0 and en bloc resection rates and without increasing adverse events. However, EMR-P required a relatively longer procedure time than CEMR. Considering its potential benefits for en bloc and R0 resection, EMR-P may be a promising technique in colorectal polyp resection.

New endoscopic tools in inflammatory bowel disease.

Endoscopic remission is now considered the ultimate long-term goal for treating inflammatory bowel disease (IBD). Recent advances in endoscopic techniques have progressively added new tools to the armamentarium of endoscopists for a deeper assessment and characterisation of the intestinal mucosa. Virtual Electronic chromoendoscopy is widely available in the endoscopic units, leading to a more accurate evaluation of the vascular and mucosal architecture of the colon, reducing the gap with histology, which is considered a favourable long-term measure. In addition, advanced, sophisticated techniques such as endocytoscope and confocal laser endomicroscopy provide insights into individualised and personalised IBD therapy. Finally, high expectations are placed on the advent of Artificial Intelligence (AI) with promising applications that have the potential to revolutionise IBD diagnosis and management. Here, we discuss state-of-the-art of endoscopic techniques and their applicability to accurate assess endoscopic and histological remission, predict response to therapy and detect, characterise and guide treatment of colonic dysplastic lesions. We are seeing the dawn of a new era wherein the applications of these new endoscopic tools, hand in hand with AI, offer the most incredible opportunity to deliver precision medicine to patients with IBD.

Deep learning-based automated quantification of goblet cell mucus using histological images as a predictor of clinical relapse of ulcerative colitis with endoscopic remission.

BACKGROUND: Mucin depletion is one of the histological indicators of clinical relapse among patients with ulcerative colitis (UC). Mucin depletion is evaluated semiquantitatively by pathologists using histological images. Therefore, the interobserver concordance is not extremely high, and an objective evaluation method is needed. This study was conducted to demonstrate that our automated quantitative method using a deep learning-based model is useful in predicting the prognosis of patients with UC. METHODS: Deep learning-based models were trained to detect goblet cell mucus area from whole slide images of biopsy specimens. This study involved 114 patients with UC in endoscopic remission with a partial Mayo score of ≤ 1. Biopsy specimens were collected during colonoscopy, and the ratio of goblet cell mucus area to the epithelial cell and goblet cell mucus area was calculated as goblet cell ratio (GCR). The follow-up time was 12 months, and the primary outcome was the relapse rate. Clinical relapse was defined as partial Mayo score of ≥ 3. RESULTS: Sixteen patients (14%) experienced clinical relapse. In the relapsed group, the GCRs of specimens obtained from the cecum, ascending colon, and rectum were significantly lower than those of specimens in the relapse-free group (p = 0.010, p = 0.027, p < 0.01). In the rectum, patients with a GCR of ≤ 12% had a significantly higher relapse rate than those with a GCR of > 12% (45% [10/22] vs. 6.5% [6/92]; p < 0.01). CONCLUSIONS: Quantifying goblet cell mucus areas using a deep learning-based model is useful in predicting the clinical relapse in patients with UC in clinical and endoscopic remission.

Histopathological assessment of the microscopic activity in inflammatory bowel diseases: What are we looking for?

Advances in diagnostics of inflammatory bowel diseases (IBD) and improved treatment strategies allowed the establishment of new therapeutic endpoints. Currently, it is desirable not only to cease clinical symptoms, but mainly to achieve endoscopic remission, a macroscopic normalization of the bowel mucosa. However, up to one-third of IBD patients in remission exhibit persisting microscopic activity of the disease. The evidence suggests a better predictive value of histology for the development of clinical complications such as clinical relapse, surgical intervention, need for therapy escalation, or development of colorectal cancer. The proper assessment of microscopic inflammatory activity thus became an important part of the overall histopathological evaluation of colonic biopsies and many histopathological scoring indices have been established. Nonetheless, a majority of them have not been validated and no scoring index became a part of the routine bioptic practice. This review summarizes a predictive value of microscopic disease activity assessment for the subsequent clinical course of IBD, describes the most commonly used scoring indices for Crohn's disease and ulcerative colitis, and comments on current limitations and unresolved issues.

An analysis of intestinal morphology and incretin-producing cells using tissue optical clearing and 3-D imaging.

Tissue optical clearing permits detailed evaluation of organ three-dimensional (3-D) structure as well as that of individual cells by tissue staining and autofluorescence. In this study, we evaluated intestinal morphology, intestinal epithelial cells (IECs), and enteroendocrine cells, such as incretin-producing cells, in reporter mice by intestinal 3-D imaging. 3-D intestinal imaging of reporter mice using optical tissue clearing enabled us to evaluate both detailed intestinal morphologies and cell numbers, villus length and crypt depth in the same samples. In disease mouse model of lipopolysaccharide (LPS)-injected mice, the results of 3-D imaging using tissue optical clearing in this study was consistent with those of 2-D imaging in previous reports and could added the new data of intestinal morphology. In analysis of incretin-producing cells of reporter mice, we could elucidate the number, the percentage, and the localization of incretin-producing cells in intestine and the difference of those between L cells and K cells. Thus, we established a novel method of intestinal analysis using tissue optical clearing and 3-D imaging. 3-D evaluation of intestine enabled us to clarify not only detailed intestinal morphology but also the precise number and localization of IECs and incretin-producing cells in the same samples.