Tamito Sasaki

Angiotensin II type 1 receptor expression in human pancreatic cancer and growth inhibition by angiotensin II type 1 receptor antagonist.

We investigated the expression of angiotensin II type 1 receptor (AT1) in pancreatic cancer. Both AT1 mRNA and protein were expressed in human pancreatic cancer tissues and cell lines. Binding assays showed that pancreatic cancer cells have specific binding sites for angiotensin II and that binding could be eliminated by treatment with a selective AT1 antagonist in a dose‐dependent fashion. Surprisingly, the growth of cancer cells was significantly suppressed by treatment with antagonist, also in a dose‐dependent manner. These observations suggest AT1 plays an important role in pancreatic cancer growth. Furthermore, ligand‐induced inhibition of AT1 may be a useful therapeutic strategy.

Expressions of Angiogenic Factors in Pancreatic Ductal Carcinoma : A Correlative Study with Clinicopathologic Parameters and Patient Survival

Introduction It has been reported that angiogenic factors play an important role in proliferation and metastasis in various cancers. Aim To investigate the expression of angiogenic factors and microvessel density (MVD) in pancreatic ductal carcinoma and to examine the correlations among expression of angiogenic factors, clinicopathologic parameters, and clinical prognosis. Methodology Paraffin-embedded specimens from 55 patients with pancreatic ductal carcinoma were immunostained for vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), platelet-derived endothelial cell growth factor (PD-ECGF), and CD34. The correlations among the expression of individual angiogenic factors and MVD, the clinicopathologic features, and the clinical prognoses were analyzed statistically. Results Immunostaining demonstrated that 70.8% of pancreatic ductal carcinomas were positive for VEGF, 60.9% for FGF-2, and 57.2% for PD-ECGF. A significant correlation was observed between VEGF expression and MVD (p < 0.05) but not between FGF-2 or PD-ECGF and MVD. Although the expression of each angiogenic factor had no correlation with clinicopathologic features, the patients with tumors that showed high expression of VEGF and FGF-2 had significantly shorter survival times than those with low or no such expression (p < 0.05). Conclusions These observations suggest that the expression of VEGF closely correlates with MVD and with a poor prognosis in pancreatic ductal carcinoma.

Multicenter study of serous cystic neoplasm of the Japan pancreas society.

Objectives There have been only a few reports on follow-up results of serous cystic neoplasm (SCN) of the pancreas. The frequency of malignancy and surgical indication of SCN are not determined yet. Methods In this multi-institutional study of the Japan Pancreas Society, a total of 172 patients with SCN were enrolled. The mean follow-up period was 4.5 years. Surgical resection was performed in 90 patients, whereas the remaining 82 were simply observed. Results Of all patients, 20% were symptomatic. The tumor was located in the pancreatic head (39%), body (35%), and tail (22%). The mean diameter of the tumor was 4.1 cm. None of the patients showed distant or lymph node metastasis except for liver metastasis found in 2 patients (1.2%). No patient died during the follow-up. The preoperative diagnosis did not correctly identify SCN in 57 (63%) of 90 resected cases. A honeycomb appearance, which is one of the most characteristic findings of SCN, could be diagnosed better by endoscopic ultrasonography than by other imaging diagnostic modalities. Conclusions Surgical resection should be considered only when clear distinction from other surgical diseases is difficult, when symptoms or mass effects are present, and when the tumor size is large.

Management of intraductal papillary-mucinous neoplasm of the pancreas: treatment strategy based on morphologic classification.

Goals The aim of this study was to examine and clarify the preoperative markers that are useful for differentiating between benign and malignant lesions of intraductal papillary-mucinous neoplasms (IPMN) of the pancreas, grouped according to morphologic classification. Background There are various stages of pathology in IPMN, ranging from benign to malignant lesions. Although the determination of appropriate treatment guidelines to deal with IPMN is a critical issue, no such guidelines have been established. Patients and Methods One hundred twenty cases of IPMN were classified morphologically into either main or branch duct types. We compared the morphologic classification with histopathologic diagnosis using indicators of malignancy detected by imaging such as main duct diameter, the number and diameter of cysts, and the presence or absence of mural nodules. We also examined the usefulness of pancreatic juice cytology and measurement of telomerase activity as indicators of malignancy. Finally, we performed a survival analysis on the basis of morphologic classification to determine prognosis of IPMN. Results Whereas a high incidence (64%) of malignant lesions was seen in main duct type IPMN, benign lesions were dominant (80.5%) in branch duct type IPMN. Survival analysis showed that the prognosis was significantly worse in main duct type than in branch duct type IPMN. The lesions were aggravated in all patients with main duct type who did not undergo resection, resulting in death due to progression of the pancreatic lesion. The incidence of mural nodules was a useful indicator in main duct type, whereas main duct diameter and incidence of mural nodules were useful indicators in branch duct type. Although pancreatic juice cytology showed a high accuracy rate with low sensitivity for determining malignancy, measurement of telomerase activity in this juice was very effective for differentiating between benign and malignant lesions. Conclusions The incidence of malignant lesions was extremely high in main duct type IPMN, indicating that surgery is required in all these patients. However, to determine whether surgery is indicated in branch duct type IPMN it is necessary to obtain an appropriate image diagnosis focusing on main duct diameter and mural nodules and also to carry out cytology and measurement of telomerase activity in samples of pancreatic juice.

Gene mutations of K-ras in gallbladder mucosae and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct

ObjectiveIn this study, we examined the mutational spectrum of K-ras in cases of gallbladder and gallbladder carcinoma with an anomalous junction of the pancreaticobiliary duct (AJPBD).MethodsWe examined 35 gallbladders with AJPBD (20 with hyperplasia, 15 with carcinoma) and 38 gallbladders without AJPBD (four normal gallbladders, four with hyperplasia, six with adenoma, 24 with carcinoma). Polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and direct sequencing were performed to detect mutations in codon 12 or 13 of K-ras.ResultsIn the cases with AJPBD, the prevalences of K-ras mutation were 15% (3/20) in hyperplasia, 60% (6/10) in stage I carcinoma, and 100% (5/5) in stage II–IV carcinoma. In the cases without AJPBD, the prevalences of K-ras mutation were 0% (0/4) in normal gallbladder, 0% (0/4) in hyperplasia, 17% (1/6) in adenoma, 7% (1/16) in stage I carcinoma, and 38% (3/8) in stage II–IV carcinoma. Prevalences of K-ras mutation in hyperplasia and carcinoma with AJPBD were greater than those without AJPBD (p < 0.05). The point mutation of GGT to GAT in codon 12 was frequently observed in the cases with AJPBD.ConclusionsThese results suggest that the specific K-ras mutation in codon 12 (GGT to GAT) may contribute to the early stage of carcinogenesis in the gallbladder with AJPBD.

Biliary Complications after Duct-to-duct Biliary Reconstruction in Living-donor Liver Transplantation: Causes and Treatment

BackgroundIn living-donor liver transplantation (LDLT), biliary complications are recognized as a significant cause of post-transplantation morbidity.MethodsEighty patients who underwent LDLT with duct-to-duct biliary reconstruction at Hiroshima University Hospital were enrolled in this study. The mean follow-up was 24 months (range, 3–72 months). Eighteen patients underwent the basiliximab-based immunosuppressive therapy, and 62 patients underwent non-basiliximab-based immunosuppressive therapy. The development of biliary complications after LDLT was retrospectively analyzed. Biliary complications were initially treated by endoscopic or radiological modalities.ResultsBiliary leakages and strictures occurred in 12 (15%) and 20 (25%) of the 80 patients, respectively. Stepwise multivariate analysis demonstrated bile leakage to be an independent risk factor for the development of biliary stricture (p = 0.001) and basiliximab-based immunosuppressive therapy to be an independent protective factor for postoperative biliary leakage (p = 0.005). The 1-week total doses of steroids were significantly lower in the basiliximab-based immunosuppressive regimes (mean dose: 573mg) than in the non-basiliximab-based ones (mean dose: 1,121mg) (p = 0.01). All patients with biliary leakage were successfully treated with endoscopic or radiological modalities, except one patient who was treated by surgical treatment. Endoscopic or radiological modalities were successful as primary treatment modalities in 12 (60%) of 20 patients with biliary strictures. Lastly, six patients were treated surgically with long-term success, except for one patient with chronic cholangitis who died after 16 months.ConclusionsSteroid-sparing basiliximab-based immunosuppressive therapy reduced the incidence of biliary leakage, and biliary leakage was the independent factor for biliary stricture. The non-surgical and surgical treatments for biliary complications were satisfactory.

A multicenter, prospective, randomized study of selective bile duct cannulation performed by multiple endoscopists: the BIDMEN study

BACKGROUND Wire-guided cannulation (WGC) with a sphincterotome (S) for selective bile duct cannulation (SBDC) has been reported to have a higher success rate and lower incidence of post-ERCP pancreatitis (PEP) than conventional methods in some randomized, controlled trials (RCTs) that were both single center and limited to only a few endoscopists. OBJECTIVE To estimate the difference in SBDC according to the method and catheter used in a multicenter and multiendoscopist study. DESIGN A prospective, multicenter RCT with a 2 × 2 factorial design. SETTING Fifteen referral endoscopy units. PATIENTS In total, 400 consecutive patients with naive papillae who were candidates for ERCP were enrolled and randomized. INTERVENTIONS Patients were assigned to 4 groups according to combined catheter (S or catheter [C]) and method (with/without guidewire [GW]). MAIN OUTCOME MEASUREMENTS Success rate of SBDC performed in 10 minutes, SBDC time, fluoroscopy time, and incidence of complications. RESULTS There was no significant difference in the SBDC success rate between the groups with and without GW, between C and S, or among the 4 groups (C+GW, C, S+GW, S). WGC had a tendency to significantly shorten cannulation and fluoroscopy times only in approximately 70% of patients in this study in whom SBDC was achieved in 10 minutes or less (P = .036 and .00004, respectively). All 4 groups resulted in similar outcomes in PEP (4%, 5.9%, 2%, and 2.1%, respectively). LIMITATIONS Non-double-blind study. CONCLUSIONS WGC appears to significantly shorten cannulation and fluoroscopy times. However, neither the method nor type of catheter used resulted in significant differences in either SBDC success rate or incidence of PEP in this RCT. ( CLINICAL TRIAL REGISTRATION NUMBER UMIN000002572.).

Long term persistence of NS5A inhibitor-resistant hepatitis C virus in patients who failed daclatasvir and asunaprevir therapy.

Although interferon‐free antiviral treatment is expected to improve treatment of hepatitis C, it is unclear to what extent pre‐existing drug‐resistant amino acid substitutions influence response to therapy. The impact of pre‐existing drug‐resistant substitutions on virological response to daclatasvir and asunaprevir combination therapy was studied in genotype 1b hepatitis C virus (HCV)‐infected patients. Thirty‐one patients were treated with daclatasvir and asunaprevir for 24 weeks. Twenty‐six patients achieved sustained virological response (SVR), three patients experienced viral breakthrough, and two patients relapsed. Direct sequencing analysis of HCV showed the existence of daclatasvir‐resistant NS5A‐L31M or ‐Y93H/F variants in nine out of 30 patients (30%) prior to treatment, while asunaprevir‐resistant NS3‐D168 mutations were not detected in any patient. All 21 patients with wild‐type NS5A‐L31 and ‐Y93 achieved SVR, whereas only four out of nine patients (44%) with L31M or Y93F/H substitutions achieved SVR (P = 0.001). Ultra‐deep sequencing analysis showed that treatment failure was associated with the emergence of both NS5A‐L31/Y93 and NS3‐D168 variants. NS5A‐L31/Y93 variants remained at high frequency through post‐treatment weeks 103 through 170, while NS3‐D168 variants were replaced by wild‐type in all patients. In conclusion, pre‐existence of NS5A inhibitor‐resistant substitutions compromised the response to daclatasvir and asunaprevir combination therapy, and treatment failure was associated with the emergence of both NS5A‐L31/Y93 and NS3‐D168 variants. While asunaprevir‐resistant variants that emerged during therapy returned to wild‐type, daclatasvir‐resistant variants tended to persist in the absence of the drug. J. Med. Virol. 87:1913–1920, 2015.

A novel TK-NOG based humanized mouse model for the study of HBV and HCV infections.

The immunodeficient mice transplanted with human hepatocytes are available for the study of the human hepatitis viruses. Recently, human hepatocytes were also successfully transplanted in herpes simplex virus type-1 thymidine kinase (TK)-NOG mice. In this study, we attempted to infect hepatitis virus in humanized TK-NOG mice and urokinase-type plasminogen activator-severe combined immunodeficiency (uPA-SCID) mice. TK-NOG mice were injected intraperitoneally with 6 mg/kg of ganciclovir (GCV), and transplanted with human hepatocytes. Humanized TK-NOG mice and uPA/SCID mice were injected with hepatitis B virus (HBV)- or hepatitis C virus (HCV)-positive human serum samples. Human hepatocyte repopulation index (RI) estimated from human serum albumin levels in TK-NOG mice correlated well with pre-transplantation serum ALT levels induced by ganciclovir treatment. All humanized TK-NOG and uPA-SCID mice injected with HBV infected serum developed viremia irrespective of lower replacement index. In contrast, establishment of HCV viremia was significantly more frequent in TK-NOG mice with low human hepatocyte RI (<70%) than uPA-SCID mice with similar RI. Frequency of mice spontaneously in early stage of viral infection experiment (8weeks after injection) was similar in both TK-NOG mice and uPA-SCID mice. Effects of drug treatment with entecavir or interferon were similar in both mouse models. TK-NOG mice thus useful for study of hepatitis virus virology and evaluation of anti-viral drugs.

Comparison of partially covered nitinol stents with partially covered stainless stents as a historical control in a multicenter study of distal malignant biliary obstruction: the WATCH study

BACKGROUND Covered self-expandable metal stents (CSEMSs) were developed to prevent tumor ingrowth, but stent migration is one of the problems with CSEMSs. OBJECTIVE To evaluate a new, commercially available CSEMS with flared ends and low axial force compared with a commercially available CSEMS without the anti-migration system and high axial force. DESIGN Multicenter, prospective study with a historical cohort. SETTING Twenty Japanese referral centers. PATIENTS This study involved patients with unresectable distal malignant biliary obstruction. INTERVENTION Placement of a new, commercially available, partially covered SEMS. MAIN OUTCOME MEASUREMENTS Recurrent biliary obstruction rate, time to recurrent biliary obstruction, stent-related complications, survival. RESULTS Between April 2009 and March 2010, 141 patients underwent partially covered nitinol stent placement, and between May 2001 and January 2007, 138 patients underwent placement of partially covered stainless stents as a historical control. The silicone cover of the partially covered nitinol stents prevented tumor ingrowth. There were no significant differences in survival (229 vs 219 days; P = .250) or the rate of recurrent biliary obstruction (33% vs 38%; P = .385) between partially covered nitinol stents and partially covered stainless stents. Stent migration was less frequent (8% vs 17%; P = .019), and time to recurrent biliary obstruction was significantly longer (373 vs 285 days; P = .007) with partially covered nitinol stents. Stent removal was successful in 26 of 27 patients (96%). LIMITATIONS Nonrandomized, controlled trial. CONCLUSION Partially covered nitinol stents with an anti-migration system and less axial force demonstrated longer time to recurrent biliary obstruction with no tumor ingrowth and less stent migration.