Yasuharu Kakizaki’s research while affiliated with Yamagata University and other places

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis. Although chemotherapy has become increasingly important in recent years, there are no practical markers to predict therapeutic efficacy. Here, we have aimed to identify novel markers that predict resistance to chemotherapy drugs using patient-derived organoids (PDOs) of PDAC. PDOs were established using endoscopic ultrasound - guided fine needle aspiration (EUS-FNA) specimens. Drug sensitivity tests were performed on 15 PDOs and the correlation between drug sensitivity and transcriptome analysis were evaluated. BARD1 and RAD50 have been identified as genes associated with gemcitabine resistance. Additionally, SLC25A10 and MAP3K9 were identified as genes associated with gemcitabine + paclitaxel resistance.PDOs derived from EUS-FNA specimens can be used to assess individual drug resistance and to identify predictive factors for chemotherapy resistance.

Objectives Localized autoimmune pancreatitis is difficult to differentiate from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. In recent years, deep learning methods have improved the diagnosis of diseases. Hence, we developed a special cross‐validation framework to search for effective methodologies of deep learning in distinguishing autoimmune pancreatitis from pancreatic ductal adenocarcinoma on endoscopic ultrasound images. Methods Data from 24 patients diagnosed with localized autoimmune pancreatitis (8751 images) and 61 patients diagnosed with pancreatic ductal adenocarcinoma (20,584 images) were collected from 2016 to 2022. We applied transfer learning to a convolutional neural network called ResNet152, together with our innovative imaging method contributing to data augmentation and temporal data process. We divided patients into five groups according to different factors for 5‐fold cross‐validation, where the ordered and balanced datasets were created for the performance evaluations. Results ResNet152 surpassed the endoscopists in all evaluation metrics with almost all datasets. Interestingly, when the dataset is balanced according to the factor of the endoscopists’ diagnostic accuracy, the area under the receiver operating characteristic curve and accuracy were highest at 0.85 and 0.80, respectively. Conclusions It is deduced that image features useful for ResNet152 correlate with those used by endoscopists for their diagnoses. This finding may contribute to sample‐efficient dataset preparation to train convolutional neural networks for endoscopic ultrasonography‐imaging diagnosis.

Although liver regeneration has been extensively studied, the effects of bile-derived extracellular vesicles (bile EVs) on hepatocytes has not been elucidated. We examined the influence of bile EVs, collected from a rat model of 70% partial hepatectomy (PH), on hepatocytes. We produced bile-duct-cannulated rats. Bile was collected over time through an extracorporeal bile duct cannulation tube. Bile EVs were extracted via size exclusion chromatography. The number of EVs released into the bile per liver weight 12 h after PH significantly increased. Bile EVs collected 12 and 24 h post-PH, and after sham surgery (PH12-EVs, PH24-EVs, sham-EVs) were added to the rat hepatocyte cell line, and 24 h later, RNA was extracted and transcriptome analysis performed. The analysis revealed that more upregulated/downregulated genes were observed in the group with PH24-EVs. Moreover, the gene ontology (GO) analysis focusing on the cell cycle revealed an upregulation of 28 types of genes in the PH-24 group, including genes that promote cell cycle progression, compared to the sham group. PH24-EVs induced hepatocyte proliferation in a dose-dependent manner in vitro, whereas sham-Evs showed no significant difference compared to the controls. This study revealed that post-PH bile Evs promote the proliferation of the hepatocytes, and genes promoting cell cycles are upregulated in hepatocytes.

Fish bone migration into the bile duct in patients with surgically altered anatomy is a very rare cause of bile duct stones. Recently, balloon-assisted endoscopic retrograde cholangiopancreatography (BAERCP) is performed for biliary lesions in patients with surgically altered anatomy. We report on a 73-year-old Japanese man with a history of pancreaticoduodenectomy for intraductal papillary mucinous adenoma. A 20 mm long linear hyperattenuating structure in the left intrahepatic bile duct was noted on routine follow-up computed tomography 14 years postoperatively. The linear structure persisted until follow-up computed tomography performed 15 years postoperatively, and the left intrahepatic bile duct was shown to be dilated. We performed BAERCP for the diagnosis and treatment of the linear structure but could not visualize the linear structure in the left intrahepatic bile duct via enteroscopy and fluoroscopy. We removed the enteroscope, leaving the overtube, and inserted the cholangioscope through the overtube over the guide wire. We observed a brown rod-shaped linear structure in the left intrahepatic bile duct and removed it under direct visualization via overtube-assisted cholangioscopy. We conclude that overtube-assisted cholangioscopy was useful for assessing undiagnosed biliary lesions using conventional BAERCP and removing fish bones in the bile duct of the patient with altered gastrointestinal anatomy.

Covered self-expandable metal stents (CSEMS) are often used for palliative endoscopic biliary drainage; however, the unobstructed period is limited because of sludge occlusion. The present study aimed to evaluate the biosafety of a novel poly(2-methoxyethyl acrylate)-coated CSEMS (PMEA-CSEMS) for sludge resistance and examine its biosafety in vivo. Using endoscopic retrograde cholangiopancreatography, we placed the PMEA-CSEMS into six normal porcine bile ducts and conventional CSEMS into three normal porcine bile ducts. We performed serological examination and undecalcified histological analysis at 1, 3, and 6 months during follow-up. In the bile ducts with PMEA-CSEMS or conventional CSEMS, we observed no increase in liver enzyme or inflammatory marker levels in the serological investigations and mild fibrosis but no inflammatory response in the histopathological analyses. Thus, we demonstrated the biosafety of PMEA-CSEMS in vivo.

Extracellular vesicles (EVs) are released from all cells. Bile directly contacts bile duct tumor; bile-derived EVs may contain high concentrations of cancer biomarkers. We performed a proteomic analysis of human bile-derived EVs and identified a novel biomarker of cholangiocarcinoma (CCA). EVs were isolated using ultracentrifugation, and chelating agents, ethylenediaminetetraacetic acid and ethylene glycol tetraacetic acid (EDEG) and phosphate buffered saline (PBS) were used as dissolution solutions. Bile was collected from 10 CCA and 10 choledocholithiasis (stones) cases. Proteomic analysis was performed; subsequently, ELISA was performed using the candidate biomarkers in a verification cohort. The vesicles isolated from bile had a typical size and morphology. The expression of exosome markers was observed. RNA was more abundant in the EDEG group. The proportion of microRNA was higher in the EDEG group. EDEG use resulted in the removal of more contaminants. Proteomic analysis identified 166 proteins as CCA-specific. ELISA for Claudin-3 revealed statistically significant difference. The diagnostic accuracy was AUC 0.945 and sensitivity and specificity were 87.5%. We report the first use of EDEG in the isolation of EVs from human bile and the proteomic analysis of human bile-derived EV-proteins in CCA. Claudin-3 in bile-derived EVs is a useful biomarker for CCA.

Treatments for hepatolithiasis include peroral endoscopy, percutaneous cholangioscopy, and surgery. Balloon-assisted endoscopic retrograde cholangiopancreatography (BAERCP) has been widely performed in recent years for patients with hepatolithiasis after biliary reconstruction. However, accidental bowel perforation caused by BAERCP may need emergency surgery. Here, we describe a 77-year-old Japanese woman diagnosed with acute cholangitis due to hepatolithiasis after biliary reconstruction (a biliary diversion operation for pancreaticobiliary maljunction). She underwent BAERCP for treatment of hepatolithiasis, however, a small-bowel perforation occurred. She underwent an emergency operation to suture the perforation and add a catheter jejunostomy. She had no postoperative complications after surgery and was discharged 11 days after surgery. One month later, she was readmitted and underwent percutaneous transjejunal cholangioscopy-guided lithotripsy with complete removal of the calculi. Although endoscopists should be careful to avoid small-bowel perforation during BAERCP, if perforation occurs, addition of a catheter jejunostomy during emergency surgery can be easily transitioned to subsequent treatment of the hepatolithiasis.

Pancreatic cancer (PC) is a highly lethal malignancy, with a 5-year survival rate of 6%. Cancer gene panel testing is expected to allow selection of suitable therapeutic drugs in individual patients with PC and improve their prognosis. Although somatic mutations can be identified in formalin-fixed, paraffin-embedded samples derived from surgical specimen, the rate of surgical indication among patients with PC is only 20%. To acquire genome information with a less invasive method, we used rapid on-site evaluation (ROSE) specimens from endoscopic ultrasound-guided fine-needle aspiration. The present study aimed to retrospectively evaluate the utility of comprehensive cancer gene panel testing with ROSE specimens. DNA was extracted from preserved ROSE specimens of 26 patients diagnosed with PC between 2011 and 2017. DNA sequences of oncogenes and cancer-related genes were determined using the Ion AmpliSeq Comprehensive Caner Panel. We compared KRAS mutations between cancer gene panel testing by next-generation sequencing (NGS) and KRAS mutation analysis by polymerase chain reaction. The mean yield of DNA per extraction from ROSE specimens was 171 ng (range, 34–478 ng). On cancer gene panel testing, we noted KRAS mutations (92%), TP53 mutations (50%), CDKN2A mutations (15%), and SMAD4 mutations (31%). The concordance rate of KRAS mutations between cancer gene panel testing by NGS using ROSE specimens and KRAS mutation analysis by the companion diagnostics using residual materials was 81%. Among five cases of KRAS discordance, three showed KRAS mutations in cancer gene panel testing but not in KRAS mutation analysis. Cancer gene panel testing with ROSE specimens can help stratify unresectable PC patients without additional invasive approaches, and it can be used for therapeutic drug selection.