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Background/Purpose: The usefulness of endoscopic biliary stenting by deploying a plastic stent suprapapillary, called inside‐stent (IS) placement, as preoperative biliary drainage (PBD) for perihilar biliary malignancy (PHBM) has been demonstrated. This study investigated risk factors for recurrent biliary obstruction (RBO) after IS placement. Methods: Consecutive patients with potentially resectable PHBM treated with IS placement as PBD between 2017 and 2023 at Nagoya University Hospital were retrospectively reviewed. Results: A total of 157 patients were included, with RBO occurring in 34 (22%) patients. The non‐RBO rates were 83% at 30 days, 77% at 60 days, and 57% at 90 days. The most common cause of RBO was stent occlusion (n = 14), followed by segmental cholangitis (n = 12) and stent migration (n = 8). Stent migration and occlusion occurred more frequently within and after 1 week post‐stenting, respectively. In multivariate analysis, biliary infection before IS was the sole risk factor for RBO, with a hazard ratio of 2.404 (95% confidence interval 1.163–4.972; p =.018). This risk was reduced by temporary endoscopic nasobiliary drainage prior to definitive IS placement. Conclusions: Biliary infection before IS was identified as an independent risk factor for RBO in patients with PHBM with IS as PBD. Clinical Trial Register: Clinical trial registration number: UMIN000025631. [ABSTRACT FROM AUTHOR]

Introduction: Inflammation in ulcerative colitis (UC) originates in the colorectal mucosa. Transcriptome sequencing analysis of the colorectal mucosa allows the identification of potential neuropeptides related to local neurotransmission. The intestinal mucus lining the surface of the mucosa may harbor biomarkers of mucosal inflammation; however, this has not been sufficiently investigated, given the difficulty in obtaining human samples. We previously reported the feasibility of obtaining mucin samples for proteomic analysis by brushing during colonoscopy. Herein, we aimed to investigate the composition of the intestinal mucus and detect neuropeptides characteristic of UC. Methods: Mucus and mucosal samples were collected from patients with UC from the colorectum in areas showing remission or active UC using a brush catheter and biopsy forceps during colonoscopy. RNA sequencing findings of mucus samples of active and remission areas were compared. RNA and protein expression levels of significantly upregulated neuropeptides were analyzed. Results: Of the neuropeptides associated with UC, somatostatin (SST) was significantly elevated in areas of remission, according to RNA sequencing results of mucus and expression levels in mucus RNA and proteins. Conversely, SST expression in the mucosa was increased in the inflamed areas. Flow cytometry revealed that the fluorescence intensity of SST-positive cells in the remission zone was higher in the mucus than in the mucosa. Conclusion: SST expression in the mucus is considered to be an important factor associated with UC activity. [ABSTRACT FROM AUTHOR]

Objectives: In this study we aimed to develop an artificial intelligence‐based model for predicting postendoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP). Methods: We retrospectively reviewed ERCP patients at Nagoya University Hospital (NUH) and Toyota Memorial Hospital (TMH). We constructed two prediction models, a random forest (RF), one of the machine‐learning algorithms, and a logistic regression (LR) model. First, we selected features of each model from 40 possible features. Then the models were trained and validated using three fold cross‐validation in the NUH cohort and tested in the TMH cohort. The area under the receiver operating characteristic curve (AUROC) was used to assess model performance. Finally, using the output parameters of the RF model, we classified the patients into low‐, medium‐, and high‐risk groups. Results: A total of 615 patients at NUH and 544 patients at TMH were enrolled. Ten features were selected for the RF model, including albumin, creatinine, biliary tract cancer, pancreatic cancer, bile duct stone, total procedure time, pancreatic duct injection, pancreatic guidewire‐assisted technique without a pancreatic stent, intraductal ultrasonography, and bile duct biopsy. In the three fold cross‐validation, the RF model showed better predictive ability than the LR model (AUROC 0.821 vs. 0.660). In the test, the RF model also showed better performance (AUROC 0.770 vs. 0.663, P = 0.002). Based on the RF model, we classified the patients according to the incidence of PEP (2.9%, 10.0%, and 23.9%). Conclusion: We developed an RF model. Machine‐learning algorithms could be powerful tools to develop accurate prediction models. [ABSTRACT FROM AUTHOR]

Background/Purpose: Data on the prognosis of endoscopic papillectomy (EP) for ampullary carcinoma (AC) is limited; therefore, we aimed to identify the factors associated with endoscopically controlled AC. Methods: Between January 2003 and October 2022, 75 patients underwent EP for ampullary tumors and were diagnosed with AC based on the pathological features of the resected tissue. The factors associated with additional surgery after EP were also evaluated. Results: A total of 67 patients had ACs ranging from carcinoma in situ to tumors limited to the mucosa (M group), and eight patients had ACs ranging from those limited to the sphincter of Oddi to those invading the duodenal muscularis propria (OD group). The 3‐year endoscopic tumor control (condition not requiring additional surgery) rates in the M and OD groups were 90.8% and 84.6% (p =.033), respectively. In the M group, the presence of tumor components in the resection margins was the only significant factor associated with additional surgeries (p =.010) in the univariate analysis. The 3‐year endoscopic tumor control rates were 100% for negative and uncertain resection margins and 76.6% for positive margins (p =.009). Conclusions: If the AC is confined to the mucosa and the resection margins are negative or uncertain, the tumor can be well‐controlled endoscopically. [ABSTRACT FROM AUTHOR]

Pancreatic stellate cells (PSCs) are stromal cells in the pancreas that play an important role in pancreatic pathology. In chronic pancreatitis (CP) and pancreatic ductal adenocarcinoma (PDAC), PSCs are known to get activated to form myofibroblasts or cancer‐associated fibroblasts (CAFs) that promote stromal fibroinflammatory reactions. However, previous studies on PSCs were mainly based on the findings obtained using ex vivo expanded PSCs, with few studies that addressed the significance of in situ tissue‐resident PSCs using animal models. Their contributions to fibrotic reactions in CP and PDAC are also lesser‐known. These limitations in our understanding of PSC biology have been attributed to the lack of specific molecular markers of PSCs. Herein, we established Meflin (Islr), a glycosylphosphatidylinositol‐anchored membrane protein, as a PSC‐specific marker in both mouse and human by using human pancreatic tissue samples and Meflin reporter mice. Meflin‐positive (Meflin+) cells contain lipid droplets and express the conventional PSC marker Desmin in normal mouse pancreas, with some cells also positive for Gli1, the marker of pancreatic tissue‐resident fibroblasts. Three‐dimensional analysis of the cleared pancreas of Meflin reporter mice showed that Meflin+ PSCs have long and thin cytoplasmic protrusions, and are localised on the abluminal side of vessels in the normal pancreas. Lineage tracing experiments revealed that Meflin+ PSCs constitute one of the origins of fibroblasts and CAFs in CP and PDAC, respectively. In these diseases, Meflin+ PSC‐derived fibroblasts showed a distinctive morphology and distribution from Meflin+ PSCs in the normal pancreas. Furthermore, we showed that the genetic depletion of Meflin+ PSCs accelerated fibrosis and attenuated epithelial regeneration and stromal R‐spondin 3 expression, thereby implying that Meflin+ PSCs and their lineage cells may support tissue recovery and Wnt/R‐spondin signalling after pancreatic injury and PDAC development. Together, these data indicate that Meflin may be a marker specific to tissue‐resident PSCs and useful for studying their biology in both health and disease. © 2023 The Pathological Society of Great Britain and Ireland. [ABSTRACT FROM AUTHOR]