Takumi Onoyama

Therapeutic effects of the dipeptidyl peptidase-IV inhibitor, sitagliptin, on non-alcoholic steatohepatitis in FLS-ob/ob male mice

Non-alcoholic steatohepatitis is characterized by hepatic fat accumulation, inflammation and varying degrees of fibrosis. The dipeptidyl peptidase‑IV enzyme is important in glucose metabolism, as well as lipid accumulation, extracellular matrix metabolism and immune stimulation. Furthermore, the enzyme activity of dipeptidyl peptidase‑IV is known to be increased in non‑alcoholic steatohepatitis. Therefore, dipeptidyl peptidase‑IV inhibitors are potential therapeutic agents for non‑alcoholic steatohepatitis. The present study assessed the therapeutic effects of sitagliptin, a dipeptidyl peptidase‑IV inhibitor, on non‑alcoholic steatohepatitis using fatty liver Shionogi‑ob/ob male mice. Sitagliptin (2 mg/kg/day; n=10) or placebo (control; n=10) was orally administered to fatty liver Shionogi‑ob/ob mice for 12 weeks, and hepatic steatosis, fibrosis, inflammation and oxidative stress were assessed in comparison with the controls. Sitagliptin administration reduced body weight and blood glucose levels, and improved hepatic fibrosis. It also inhibited the gene expression levels of fatty acid synthase, transforming growth factor‑β1, tissue inhibitor of metalloproteinases‑1, procollagen‑type 1, tumor necrosis factor‑α, monocyte chemoattractant protein‑1 and enhanced peroxisome proliferator activated receptor‑α. Furthermore, a marked attenuation of hepatic stellate cell activation and Kupffer cells was observed in the sitagliptin group. A decrease in oxidative stress and apoptosis was also observed. Sitagliptin attenuated the progression of hepatic fibrosis by improving lipid metabolism, inflammation and oxidative stress in non-alcoholic steatohepatitis.

Antifibrotic effects of ambrisentan,an endothelin-A receptor antagonist,in a non-alcoholic steatohepatitis mouse model

AIM To examine the effects of the endothelin type A receptor antagonist ambrisentan on hepatic steatosis and fibrosis in a steatohepatitis mouse model. METHODS Fatty liver shionogi (FLS) FLS-ob/ob mice (male, 12 wk old) received ambrisentan (2.5 mg/kg orally per day; n = 8) or water as a control (n = 5) for 4 wk. Factors were compared between the two groups, including steatosis, fibrosis, inflammation, and endothelin-related gene expression in the liver. RESULTS In the ambrisentan group, hepatic hydroxyproline content was significantly lower than in the control group (18.0 μg/g ± 6.1 μg/g vs 33.9 μg/g ± 13.5 μg/g liver, respectively, P = 0.014). Hepatic fibrosis estimated by Sirius red staining and areas positive for α-smooth muscle actin, indicative of activated hepatic stellate cells, were also significantly lower in the ambrisentan group (0.46% ± 0.18% vs 1.11% ± 0.28%, respectively, P = 0.0003; and 0.12% ± 0.08% vs 0.25% ± 0.11%, respectively, P = 0.047). Moreover, hepatic RNA expression levels of procollagen-1 and tissue inhibitor of metalloproteinase-1 (TIMP-1) were significantly lower by 60% and 45%, respectively, in the ambrisentan group. Inflammation, steatosis, and endothelin-related mRNA expression in the liver were not significantly different between the groups. CONCLUSION Ambrisentan attenuated the progression of hepatic fibrosis by inhibiting hepatic stellate cell activation and reducing procollagen-1 and TIMP-1 gene expression. Ambrisentan did not affect inflammation or steatosis.

Role of the preoperative usefulness of the pathological diagnosis of pancreatic diseases.

Pancreatic cancer is the fifth leading cause of cancer death and has the lowest survival rate of any solid cancer. Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) is currently capable of providing a cytopathological diagnosis of pancreatic malignancies with a higher diagnostic power, with a sensitivity and specificity of 85%-89% and 98%-99%, compared to pancreatic juice cytology (PJC), whose sensitivity and specificity are only 33.3%-93% and 83.3%-100%. However, EUS-FNA is not effective in the cases of carcinoma in situ and minimally invasive carcinoma because both are undetectable by endoscopic ultrasonography, although PJC is able to detect them. As for the frequency of complications such as post endoscopic retrograde cholangiopancreatography pancreatitis, EUS-FNA is safer than PJC. To diagnose pancreatic cancer appropriately, it is necessary for us to master both procedures so that we can select the best methods of sampling tissues while considering the patient’s safety and condition.

Development of a device for detecting target specimens from EUS-guided FNA samples

Background and study aims: Specimens collected by fine needle are microscopic and contain blood; therefore, the presence of a target specimen within a sample is often difficult to confirm. Although rapid on-site evaluation (ROSE) during endoscopic ultrasound-guided fine needle aspiration biopsy (EUS-FNA) is beneficial, many health care facilities are unable to apply this technique due to a lack of cytopathologists. The aim of this study was to develop and validate a device that detects the target specimen within pancreatic tumor EUS-FNA samples. Patients and methods: Fifty-eight consecutive patients with solid pancreatic masses were studied for a preliminary case series at a tertiary-care university hospital (Tottori University Hospital, Yonago, Japan). The material collected was checked with a target sample check illuminator (TSCI) and was evaluated by one cytopathologist. Results: The agreement rate between the TSCI and histopathology was 93.7 %. Further testing procedures were not needed in 91.4 % of patients, and the mean number of needle punctures was 1.2 after a single pass using TSCI. No adverse events were encountered with the procedure. Conclusions: With the introduction of the TSCI in EUS-FNA, it became possible to both collect the minimum necessary target samples by EUS-FNA and to end further procedures, even without performing ROSE.

Clinical Impact of the KL-6 Concentration of Pancreatic Juice for Diagnosing Pancreatic Masses.

Background and Aim. Pancreatic juice cytology (PJC) is considered optimal for differentially diagnosing pancreatic masses, but the accuracy of PJC ranges from 46.7% to 93.0%. The aim of this study was to evaluate the clinical impact of measuring the KL-6 concentration of pancreatic juice for diagnosing pancreatic masses. Methods. PJC and the KL-6 concentration measurements of pancreatic juice were performed for 70 consecutive patients with pancreatic masses (39 malignancies and 31 benign). Results. The average KL-6 concentration of pancreatic juice was significantly higher for pancreatic ductal adenocarcinomas (PDACs) (167.7 ± 396.1 U/mL) and intraductal papillary mucinous carcinomas (IPMCs) (86.9 ± 21.1 U/mL) than for pancreatic inflammatory lesions (17.5 ± 15.7 U/mL, P = 0.034) and intraductal papillary mucinous neoplasms (14.4 ± 2.0 U/mL, P = 0.026), respectively. When the cut-off level of the KL-6 concentration of pancreatic juice was 16 U/mL, the sensitivity, specificity, and accuracy of the KL-6 concentration of pancreatic juice alone were 79.5%, 64.5%, and 72.9%, respectively. Adding the KL-6 concentration of pancreatic juice to PJC when making a diagnosis caused the values of sensitivity and accuracy of PJC to increase by 15.3% (P = 0.025) and 8.5% (P = 0.048), respectively. Conclusions. The KL-6 concentration of pancreatic juice may be as useful as PJC for diagnosing PDACs.

Diagnostic usefulness of KL-6 concentration of bile in biliary tract cancer

The sensitivity of bile cytology for biliary tract cancer varies from 6-64%, and hence remains unsatisfactory. Sialylated carbohydrate antigen KL-6 mucin is positive in biliary tract cancer tissues and serum KL-6 levels are significantly increased in intrahepatic ductal adenocarcinoma patients compared with healthy individuals. The aim of the present study was to evaluate the usefulness of the KL-6 concentration of bile for the diagnosis of biliary tract cancer. Bile cytology and measurements of bile KL-6 concentration were conducted for 43 patients (25 biliary tract cancers and 18 benign biliary disease). The concentration of KL-6 in the bile of the biliary tract cancer group was compared with the benign biliary disease group. The diagnostic ability was assessed by using receiver operating characteristic curves (ROC). The mean KL-6 concentration of bile for biliary tract cancer (34.6±51.6 U/ml) was increased compared with benign biliary disease (5.2±3.9 U/ml, P<0.001). The area under the ROC for diagnosis of biliary tract cancer was 0.84 for benign biliary disease. When the cut-off level of the KL-6 concentration of bile was 8.6 U/ml, the sensitivity, specificity, and accuracy of the KL-6 concentration of bile alone for the diagnosis of biliary tract cancer were 72, 89, and 79%, respectively. Adding the bile KL-6 concentration to bile cytology measurements, the sensitivity for the diagnosis of biliary tract cancer was increased significantly (100%, P=0.0184). The KL-6 concentration of bile may strengthen the sensitivity of bile cytology for biliary tract cancer.

Efficacy and safety of pancreatic juice cytology by using synthetic secretin in the diagnosis of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is difficult to detect in its early stages with the poorest prognosis of all cancers. To improve the prognosis, a precise diagnosis is needed when we suspect PDAC. Although endoscopic ultrasound‐guided fine‐needle aspiration biopsy (EUS‐FNA) is a widely accepted modality for the diagnosis of PDAC, its sensitivity is 85–89%, and approximately 10% of PDAC cases cannot be diagnosed. The main causes that interrupt the diagnosis of PDAC by using EUS‐FNA are tumor size, presence of a vessel or the main pancreatic duct along the puncture route, and difficulty in withdrawing anticoagulant. Pancreatic juice cytology (PJC), the sensitivity of which is 33.3–65.8%, is a method for the diagnosis of PDAC cases in which carrying out of EUS‐FNA is difficult. To diagnose PDAC appropriately, we need to improve the diagnostic ability of PJC.

Utility of virtual touch quantification in the diagnosis of pancreatic ductal adenocarcinoma

This study aimed to compare the tissue stiffness of pancreatic ductal adenocarcinoma (PDAC) with that of pancreatic parenchyma using virtual touch quantification (VTQ). SWV was measured in 34 PDAC lesions and in pancreatic parenchyma of both controls and patients. SWVs in PDAC lesions were significantly higher than in pancreatic parenchyma in both healthy controls and in patients with PDAC. The area under the ROC for diagnosis of PDAC was 0.94 for pancreatic parenchyma in healthy controls, and 0.85 for pancreatic parenchyma in patients with PDAC. VTQ can provide a useful and additional information for diagnosis of PDAC.