New gel immersion endoscopic ultrasonography technique for accurate periampullary evaluation.

BACKGROUND: Visualization of the pancreatobiliary junction is one of the challenges faced by endoscopic ultrasonography (EUS). The water-filling technique, which allows for the observation of the ampulla at a suitable distance by injecting water into the lumen of the duodenum, was used for this purpose. However, a new gel immersion technique has recently been introduced for visualizing the gastrointestinal tract. This study investigated the effectiveness of visualizing the pancreatobiliary junction in EUS by comparing both water filling and the new gel immersion technique in identical cases. METHODS: The study ran from June to December 2021. Ten images from each technique were retrospectively compared by three independent researchers. The primary result of the study was the number of images depicting the "Pancreatic and Biliary Ducts Penetrating the Duodenal Muscularis Propria" (defined as Excellent observation) in each technique. The secondary outcome was defined as gel immersion technique's safety and impact on duodenal lumen distension. RESULTS: Ten patients used the gel immersion technique. All patients underwent the water-filling technique first, followed by gel injection after the water was completely aspirated. The average number of pictures rated as "Excellent observation," which is the primary outcome, was significantly higher with the gel immersion technique than with water filling, and no adverse events were observed. The subanalysis revealed that both convex and radial echoendoscopes are equally effective at depicting the ampulla with the gel immersion technique. CONCLUSIONS: The ability to depict the pancreatobiliary junction using the gel immersion technique is superior to that of the water-filling method, which may allow for a more detailed assessment of the ampullary region with both radial and convex echoendoscopes. This can be a useful EUS technique for diagnosing pancreaticobiliary maljunction or periampullary tumors.

Liquid Biopsy for Pancreatic Cancer by Serum Extracellular Vesicle-Encapsulated Long Noncoding RNA HEVEPA.

OBJECTIVES: The role of long noncoding RNAs (lncRNAs) in pancreatic ductal adenocarcinoma (PDAC) remain unclear. Extracellular vesicle (EV)-encapsulated RNAs could be effective targets for liquid biopsy. We aimed to identify previously unknown EV-encapsulated lncRNAs in PDAC and establish highly accurate methods for isolating EVs. MATERIALS AND METHODS: Extracellular vesicles were isolated using existing and newly developed methods, namely, PEViA-UC and PEViA-IP, from serum samples of 20 patients with PDAC, 22 patients with intraductal papillary mucinous neoplasms, and 21 healthy individuals. Extracellular vesicle lncRNA expression was analyzed using digital PCR. RESULTS: Gene expression analysis using cDNA microarray revealed a highly expressed lncRNA, HEVEPA , in serum EVs from patients with PDAC. We established PEViA-UC and PEViA-IP using PEViA reagent, ultracentrifugation, and immunoprecipitation. Although detection of EV-encapsulated HEVEPA using existing methods is challenging, PEViA-UC and PEViA-IP detected EV HEVEPA , which was highly expressed in patients with PDAC compared with non-PDAC patients. The detection sensitivity for discriminating PDAC from non-PDAC using the combination of HEVEPA and HULC , which are highly expressed lncRNAs in PDAC, and carbohydrate antigen 19-9 (CA19-9), was higher than that of HEVEPA , HULC , or CA19-9 alone. CONCLUSIONS: Extracellular vesicle lncRNAs isolated using PEViA-IP and CA19-9 together could be effective targets in liquid biopsy for PDAC diagnosis.