Taizo Hibi

Chromatin remodeling at Alu repeats by epigenetic treatment activates silenced microRNA-512-5p with downregulation of Mcl-1 in human gastric cancer cells.

Epigenetic therapy using DNA methylation inhibitors and histone deacetylase (HDAC) inhibitors has clinical promise for the treatment of human malignancies. To investigate roles of microRNAs (miRNAs) on epigenetic therapy of gastric cancer, the miRNA expression profile was analysed in human gastric cancer cells treated with 5-aza-2′-deoxycytidine (5-Aza-CdR) and 4-phenylbutyric acid (PBA). miRNA microarray analysis shows that most of miRNAs activated by 5-Aza-CdR and PBA in gastric cancer cells are located at Alu repeats on chromosome 19. Analyses of chromatin modification show that DNA demethylation and HDAC inhibition at Alu repeats activates silenced miR-512-5p by RNA polymerase II. In addition, activation of miR-512-5p by epigenetic treatment induces suppression of Mcl-1, resulting in apoptosis of gastric cancer cells. These results suggest that chromatin remodeling at Alu repeats plays critical roles in the regulation of miRNA expression and that epigenetic activation of silenced Alu-associated miRNAs could be a novel therapeutic approach for gastric cancer.

Laparoscopic surgery for recurrent Crohn's disease†

The aim of this study was to assess the feasibility of laparoscopic surgery for recurrent Crohns disease, and the role of repeated laparoscopy in reoperation.

When and why portal vein thrombosis matters in liver transplantation: A critical audit of 174 cases

Objective:To identify complications associated with different techniques utilized to treat portal vein thrombosis (PVT) during primary liver transplantation and their impact on survival. Background:PVT remains an intricate problem in liver transplantation, and the long-term outcomes of patients with PVT who undergo transplantation are not well defined. Methods:We performed a retrospective cohort analysis of all consecutive adult patients who underwent primary isolated liver transplantation from 1998 to 2009 (median follow-up period, 89 months). The outcomes of patients with PVT were compared with those without PVT. Results:Among 1379 recipients, 174 (12.6%) had PVT at the time of transplantation [83 (48%) complete and 91 (52%) partial]. Among PVT patients with reestablished physiological portal inflow (PVT: physiological group; n = 149), 123 underwent thrombectomies, 16 received interpositional vein grafts, and 10 received mesoportal jump grafts. In 25 patients, physiological portomesenteric venous circulation was not reconstituted (PVT: nonphysiological group; 18 underwent cavoportal hemitranspositions, 6 renoportal anastomoses, and 1 arterialization). The PVT: nonphysiological group suffered a significantly increased incidence of rethrombosis of the portomesenteric veins and gastrointestinal bleeding, with a marginal 10-year overall survival rate of 42% (no PVT, 61%; P = 0.002 and PVT: physiological, 55%; P = 0.043). The PVT: physiological and no PVT groups exhibited comparable survival rates (P = 0.13). No significant differences in survival were observed between complete and partial PVT as long as physiological portal flow was reestablished. Conclusions:The subset of PVT patients requiring nonphysiological portal vein reconstruction was associated with higher complication rates and suffered diminished long-term prognoses. For the most severe PVT cases, a comprehensive approach is critical to further improve outcomes.

Synuclein-γ Is Closely Involved in Perineural Invasion and Distant Metastasis in Mouse Models and Is a Novel Prognostic Factor in Pancreatic Cancer

Purpose: Perineural invasion is associated with the high incidence of local recurrence and a dismal prognosis in pancreatic cancer. We previously reported a novel perineural invasion model and distinguished high– and low–perineural invasion groups in pancreatic cancer cell lines. This study aimed to elucidate the molecular mechanism of perineural invasion. Experimental Design: To identify key biological markers involved in perineural invasion, differentially expressed molecules were investigated by proteomics and transcriptomics. Synuclein-γ emerged as the only up-regulated molecule in high–perineural invasion group by both analyses. The clinical significance and the biological property of synuclein-γ were examined in 62 resected cases of pancreatic cancer and mouse models. Results: Synuclein-γ overexpression was observed in 38 (61%) cases and correlated with major invasive parameters, including perineural invasion and lymph node metastasis (P < 0.05). Multivariate analyses revealed synuclein-γ overexpression as the only independent predictor of diminished overall survival [hazard ratio, 3.4 (95% confidence interval, 1.51-7.51)] and the strongest negative indicator of disease-free survival [2.8 (1.26-6.02)]. In mouse perineural invasion and orthotopic transplantation models, stable synuclein-γ suppression by short hairpin RNA significantly reduced the incidence of perineural invasion (P = 0.009) and liver/lymph node metastasis (P = 0.019 and P = 0.020, respectively) compared with the control. Conclusions: This is the first study to provide in vivo evidence that synuclein-γ is closely involved in perineural invasion/distant metastasis and is a significant prognostic factor in pancreatic cancer. Synuclein-γ may serve as a promising molecular target of early diagnosis and anticancer therapy.

CD44 variant 9 expression in primary early gastric cancer as a predictive marker for recurrence

Background:Multiple early gastric cancers (EGCs) may develop in 6–14% of patients even after achieving curative endoscopic submucosal dissection (ESD); however, a useful biomarker for predicting recurrence is not available. The present study investigated whether the expression of CD44 variant 9 (CD44v9), a functional cancer stem cell marker, in the primary gastric cancer tissue represents an indicator of recurrence.Methods:Eighty-eight patients who underwent ESD for EGC from 2008 to 2010 were enrolled and monitored for recurrence for 3 years. The expression levels of CD44v9 in the tissue of initial EGCs were evaluated by immunohistochemistry, and the recurrence rate was compared between CD44v9-positive and CD44v9-negative groups. The mucin phenotype and expression of microRNA-21 (miR-21) and programmed cell death protein 4 (PDCD4) were also analysed.Results:The recurrence rate of EGC was significantly higher in the CD44v9-positive group than in the CD44v9-negative group (hazard ratio (HR), 21.8; 95% confidence interval (CI), 5.71–83.1). However, mucin phenotypes and the expression of miR-21 and PDCD4 did not predict recurrence after ESD. Meanwhile, grade of gastric atrophy was also identified as a significant marker of multiple recurrence (HR, 4.95; 95% CI, 1.30–18.8).Conclusion:CD44 variant 9 expression represents a potential predictive marker for recurrence in EGC.

Randomized clinical trial: rikkunshito in the treatment of functional dyspepsia—a multicenter, double-blind, randomized, placebo-controlled study

Rikkunshito, a standardized Japanese herbal medicine, is thought to accelerate gastric emptying and relieve dyspepsia, although no large‐scale, randomized, placebo‐controlled trials of rikkunshito have been conducted. This study aimed to determine the efficacy and safety of rikkunshito for treating functional dyspepsia (FD).

Effect of dietary anti‐Helicobacter pylori‐urease immunoglobulin Y on Helicobacter pylori infection

Recently, chicken egg yolk was recognized as an inexpensive antibody source, and the therapeutic usefulness of egg yolk immunoglobulin Y (IgY) in oral passive immunization has been investigated. Although multiple antibiotic treatments eradicate most Helicobacter pylori (H. pylori) infections, therapy fails in 10–15% of cases due to the development of drug resistance. Consequently, it is important that new, more broadly based therapies for the treatment of H. pylori infection should be identified. The present study evaluated the effect, on H. pylori infection, of IgY prepared from egg yolk of hens immunized with H. pylori urease (anti‐HpU IgY). Seventeen asymptomatic volunteers diagnosed as H. pylori‐positive by the 13C‐urea breath test (UBT) were orally administered anti‐HpU IgY for 4 weeks. Four weeks later, UBT values were significantly decreased although no case showed H. pylori eradication. An H. pylori‐positive 53‐year‐old female gastritis patient administered anti‐HpU IgY plus lansoprazole for 8 weeks showed a decrease in serum pepsinogen (PG) I and UBT values as well as an increase in the PG I/II ratio. In conclusion, anti‐HpU IgY may mitigate H. pylori‐associated gastritis and partially attenuate gastric urease activity. Furthermore, anti‐HpU IgY combined with antacids appears to ameliorate gastric inflammation. These encouraging results may represent a novel approach to the management of H. pylori‐associated gastroduodenal disease.

Adenylate cyclase-associated protein 1 overexpressed in pancreatic cancers is involved in cancer cell motility

Pancreatic cancer has the worst prognosis among cancers due to the difficulty of early diagnosis and its aggressive behavior. To characterize the aggressiveness of pancreatic cancers on gene expression, pancreatic cancer xenografts transplanted into severe combined immunodeficient mice served as a panel for gene-expression profiling. As a result of profiling, the adenylate cyclase-associated protein 1 (CAP1) gene was shown to be overexpressed in all of the xenografts. The expression of CAP1 protein in all 73 cases of pancreatic cancer was recognized by immunohistochemical analyses. The ratio of CAP1-positive tumor cells in clinical specimens was correlated with the presence of lymph node metastasis and neural invasion, and also with the poor prognosis of patients. Immunocytochemical analyses in pancreatic cancer cells demonstrated that CAP1 colocalized to the leading edge of lamellipodia with actin. Knockdown of CAP1 by RNA interference resulted in the reduction of lamellipodium formation, motility, and invasion of pancreatic cancer cells. This is the first report demonstrating the overexpression of CAP1 in pancreatic cancers and suggesting the involvement of CAP1 in the aggressive behavior of pancreatic cancer cells.

Clinical usefulness of microsatellite instability for the prediction of gastric adenoma or adenocarcinoma in patients with chronic gastritis

To assess a role of microsatellite instability (MSI) in the development of gastric adenocarcinoma or adenoma from chronic gastritis, we analysed mutations of five microsatellite loci in gastritis, adenoma and adenocarcinoma retrospectively. Gastric mucosa was biopsied from the same area in each patient at different periods and examined for MSI. Only one of 55 patients with chronic gastritis revealed MSI-H phenotype and the other 54 patients showed microsatellite stable (MSS) phenotypes. In six of 17 patients with gastric adenoma or well-differentiated adenocarcinoma, MSI-positive phenotypes were demonstrated. Interestingly, all of six patients showing MSI, including three high-level MSI (MSI-H) cases and three low-level (MSH-L) cases, had already revealed MSI at the stage of chronic gastritis. In two of three MSI-H cases, the identical MSI patterns had been observed at the stage of gastritis 1.5–7 years before the final diagnosis of adenocarcinoma. The adjacent gastritis mucosa within 10 mm from the carcinoma demonstrated MSI as well. MSI was not found in any of 35 patients with Helicobacter pylori infection, but found in one of 30 patients without infection. Moreover, two of three cases of gastric adenoma or well-differentiated adenocarcinoma with MSI-H at the stage of chronic gastritis showed no evidence of Helicobacter pylori infection throughout the observation periods. These results indicate that MSI in biopsy specimens at the stage of chronic gastritis may predict the risk of the progression to adenoma and well-differentiated adenocarcinoma, and that Helicobacter pylori infection itself may not induce MSI directly in the gastric mucosa.

The influence of donor age on liver regeneration and hepatic progenitor cell populations.

BACKGROUND Recent reports suggest that donor age might have a major impact on recipient outcome in adult living donor liver transplantation (LDLT), but the reasons underlying this effect remain unclear. The aims of this study were to compare liver regeneration between young and aged living donors and to evaluate the number of Thy-1+ cells, which have been reported to be human hepatic progenitor cells. METHODS LDLT donors were divided into 2 groups (Group O, donor age ≥ 50 years, n = 6 and Group Y, donor age ≤ 30 years, n = 9). The remnant liver regeneration rates were calculated on the basis of computed tomography volumetry on postoperative days 7 and 30. Liver tissue samples were obtained from donors undergoing routine liver biopsy or patients undergoing partial hepatectomy for metastatic liver tumors. Thy-1+ cells were isolated and counted using immunomagnetic activated cell sorting (MACS) technique. RESULTS Donor liver regeneration rates were significantly higher in young donors compared to old donors (P = .042) on postoperative day 7. Regeneration rates were significantly higher after right lobe resection compared to rates after left lobe resection. The MACS findings showed that the number of Thy-1+ cells in the human liver consistently tended to decline with age. CONCLUSION Our study revealed that liver regeneration is impaired with age after donor hepatectomy, especially after right lobe resection. The declining hepatic progenitor cell population might be one of the reasons for impaired liver regeneration in aged donors.