Visualization of Absorbed Lipid in the Normal Duodenal Epithelium Using Magnifying Endoscopy with Narrow-Band Imaging

Endoscopic Diagnosis of Epithelial Subtypes of Superficial Non-Ampullary Duodenal Epithelial Tumors using Magnifying Narrow-Band Imaging

INTRODUCTION

Superficial non-ampullary duodenal epithelial tumors (SNADETs) include low-grade adenoma (LGA) and high-grade adenoma or carcinoma (HGA/Ca) and are classified into two different epithelial subtypes, gastric-type (G-type) and intestinal-type (I-type). We attempted to distinguish them by endoscopic characteristics including magnifying endoscopy with narrow-band imaging (M-NBI).

METHODS

Various endoscopic and M-NBI findings of 286 SNADETs were retrospectively reviewed and compared between G- and I-types and histological grades. M-NBI findings were divided into four patterns based on the following vascular patterns; absent, network, intrastructural vascular (ISV), and unclassified. Lesions displaying a single pattern were classified as mono-pattern and those displaying multiple patterns as mixed-pattern. Lesions showing CDX2 positivity were categorized as I-types and those showing MUC5AC or MUC6 positivity were categorized as G-types based on immunohistochemistry.

RESULTS

Among 286 lesions, 23 (8%) were G-type and 243 (85%) were I-type. More G-type lesions were located oral to papilla (91.3 vs. 45.6%, p < 0.001), and had protruding morphology compared to those of I-types (65.2 vs. 14.4%, p < 0.001). The major M-NBI pattern was ISV in G-type (78.2 vs. 26.3%, p < 0.001), and absent for I-type (0 vs. 34.5%, p = 0.003). Three endoscopic characteristics; location oral to papilla, protruding morphology, and major M-NBI pattern (ISV) were independent predictors for G-type. Mixed-pattern was more common in HGA/Ca than LGA for I-type (77.0 vs. 58.8%, p = 0.01); however, there was no difference for those in G-type.

CONCLUSION

Endoscopic findings including M-NBI are useful to differentiate epithelial subtypes.

Delineation of the healthy rabbit duodenum by immunohistochemistry - A short communication

The duodenum acts as a vital organ that performs fundamental physiological functions like digestion and nutrient absorption. Situated in the lower abdomen, the duodenum is located between the stomach and the jejunum. Usually, the duodenum is divided into four anatomical portions. We here compare paraffin embedded and cryosections of the healthy rabbit duodenum for research purposes. This analysis evaluates the differential outcomes resulting from the application of these fixation methodologies in conjunction with immunohistochemical assays targeting extracellular matrix markers collagen I, collagen III, fibronectin, α-smooth muscle actin (α-SMA), and proliferation marker ki67 as well as inflammatory marker PAR-2. Subsequent recommendations are provided based on our findings. Furthermore, the advantage of an antigen retrieval step in immunohistochemical labelling of paraffin sections was demonstrated and confirmed with an isotype negative control. Basic classical histological stainings as HE, GT and elastin were also performed. Comparison of different stainings and labellings was performed in serial sections, showing that adjacent to the circular muscle of the duodenum, the connective tissue was composed of collagen I and fibronectin, while the artery and vein walls were predominantly α-SMA positive. Moreover, PAR-2 immunohistochemical staining was performed, where particularly a type of gland adjacent to Brunner's glands showed prominent PAR-2 positive areas, while the Brunner's glands themselves were PAR-2 negative. Proliferating ki67 positive cells facing the lumen were highly abundant in all kinds of glands except for the Brunner's glands. This effort serves to furnish the research community with reference imagery pertinent to scientists opting for the rabbit duodenum model. The diversity of staining techniques employed herein establishes a foundational repository of images, primed for comparative analysis against pathological conditions. Furthermore, these images hold the potential to illustrate inter-species variations. For instance, they can be juxtaposed against murine or rat intestinal tracts, or even offer insights into the human context.