Mari Yamagami

Efficacy of tolvaptan in patients with refractory ascites in a clinical setting

AIM To elucidate the efficacies of tolvaptan (TLV) as a treatment for refractory ascites compared with conventional treatment. METHODS We retrospectively enrolled 120 refractory ascites patients between January 1, 2009 and September 31, 2014. Sixty patients were treated with oral TLV at a starting dose of 3.75 mg/d in addition to sodium restriction (> 7 g/d), albumin infusion (10-20 g/wk), and standard diuretic therapy (20-60 mg/d furosemide and 25-50 mg/d spironolactone) and 60 patients with large volume paracentesis in addition to sodium restriction (less than 7 g/d), albumin infusion (10-20 g/wk), and standard diuretic therapy (20-120 mg/d furosemide and 25-150 mg/d spironolactone). Patient demographics and laboratory data, including liver function, were not matched due to the small number of patients. Continuous variables were analyzed by unpaired t-test or paired t-test. Fishers exact test was applied in cases comparing two nominal variables. We analyzed factors affecting clinical outcomes using receiver operating characteristic curves and multivariate regression analysis. We also used multivariate Coxs proportional hazard regression analysis to elucidate the risk factors that contributed to the increased incidence of ascites. RESULTS TLV was effective in 38 (63.3%) patients. The best cut-off values for urine output and reduced urine osmolality as measures of refractory ascites improvement were > 1800 mL within the first 24 h and > 30%, respectively. Multivariate regression analysis indicated that > 25% reduced urine osmolality [odds ratio (OR) = 20.7; P < 0.01] and positive hepatitis C viral antibodies (OR = 5.93; P = 0.05) were positively correlated with an improvement of refractory ascites, while the total bilirubin level per 1.0 mg/dL (OR = 0.57; P = 0.02) was negatively correlated with improvement. In comparing the TLV group and controls, only the serum sodium level was significantly lower in the TLV group (133 mEq/L vs 136 mEq/L; P = 0.02). However, there were no significant differences in the other parameters between the two groups. The cumulative incidence rate was significantly higher in the control group with a median incidence time of 30 d in the TLV group and 20 d in the control group (P = 0.01). Cox hazard proportional multivariate analysis indicated that the use of TLV (OR = 0.58; P < 0.01), uncontrolled liver neoplasms (OR = 1.92; P < 0.01), total bilirubin level per 1.0 mg/dL (OR = 1.10; P < 0.01), and higher sodium level per 1.0 mEq/L (OR = 0.94; P < 0.01) were independent factors that contributed to incidence. CONCLUSION Administration of TLV results in better control of refractory ascites and reduced the incidence of additional invasive procedures or hospitalization compared with conventional ascites treatments.

MicroRNAs and liver disease.

The biological roles of microRNAs (miRNAs) have been extensively studied. miRNA122 represents more than half of the miRNAs expressed in the liver and has various physiological and pathological functions, which include enhancing hepatitis virus replication, regulating lipid metabolism and suppressing hepatocellular carcinoma. miRNAs, whether globally or individually, have been linked with hepatocarcinogenesis. Furthermore, some miRNAs have been shown to be involved in the pathogenesis of nonalcoholic steatohepatitis. Using nucleotide-based strategies, these miRNAs may be developed as potential therapeutic targets. Because changes in miRNA expression can be measured in sera, they may be used as non-invasive biomarkers if they correctly reflect the pathological state of the liver. In this review, we show the biological roles of representative miRNAs in liver disease and discuss the current issues that remain to be clarified for future clinical applications.

DHX9 regulates production of hepatitis B virus-derived circular RNA and viral protein levels

Hepatitis B virus (HBV) infection, which is a major health concern worldwide, can lead to liver cirrhosis and hepatocellular carcinoma. Although current nucleos(t)ide analogs efficiently inhibit viral reverse transcription and viral DNA load clinically, episomal viral covalently closed circular DNA (cccDNA) minichromosomes and transcripts from cccDNA continue to be expressed over the long term. We hypothesized that, under these conditions, viral transcripts may have biological functions involved in pathogenesis. Here, we show that the host protein DExH-box helicase 9 (DXH9) is associated with viral RNAs. We also show that viral-derived circular RNA is produced during HBV replication, and the amount is increased by knockdown of the DHX9 protein, which, in turn, results in decreased viral protein levels but does not affect the levels of HBV DNA. These phenomena were observed in the HBV-producing cell culture model and HBV mini-circle model mimicking HBV cccDNA, as well as in human primary hepatocytes infected with HBV. Based on these results, we conclude that, in HBV infection, the RNA binding factor DHX9 is a novel regulator of viral circular RNA and viral protein levels.

Satellite RNA Increases DNA Damage and Accelerates Tumor Formation in Mouse Models of Pancreatic Cancer

Highly repetitive tandem arrays such as satellite sequences in the centromeric and pericentromeric regions of chromosomes, which were previously considered to be silent, are actively transcribed in various biological processes, including cancers. In the pancreas, this aberrant expression occurs even in Kras-mutated pancreatic intraepithelial neoplasia (PanIN) tissues, which are precancerous lesions. To determine the biological role of satellite RNAs in carcinogenesis in vivo, we constructed mouse major satellite (MajSAT) RNA-expressing transgenic mice. However, these transgenic mice did not show spontaneous malignant tumor formation under normal breeding. Importantly, however, DNA damage was increased in pancreatic tissues induced by caerulein treatment or high-fat diet, which may be due to impaired nuclear localization of Y-Box Binding Protein 1 (YBX1), a component of the DNA damage repair machinery. In addition, when crossed with pancreas-specific Kras-mutant mice, MajSAT RNA expression resulted in an earlier increase in PanIN formation. These results suggest that aberrant MajSAT RNA expression accelerates oncogenesis by increasing the probability of a second driver mutation, thus accelerating cells to exit from the breakthrough phase to the expansion phase. Implications: Aberrant expression of satellite RNAs accelerates oncogenesis through a mechanism involving increased DNA damage. Mol Cancer Res; 16(8); 1255–62. ©2018 AACR.

RASAL1 is a potent regulator of hepatic stellate cell activity and liver fibrosis

Liver fibrosis, leading to cirrhosis and liver failure, can occur after chronic liver injury. The transition of hepatic stellate cells (HSCs) from quiescent cells into proliferative and fibrogenic cells is a central event in liver fibrosis. Here, we show that RAS protein activator like-1 (RASAL1), a RAS-GTPase-activating protein, which switches off RAS activity, is significantly decreased during HSC activation, and that HSC activation can be antagonized by forced expression of the RASAL1 protein. We demonstrate that RASAL1 suppresses HSC proliferation by regulating the Ras-MAPK pathway, and that RASAL1 suppresses HSC fibrogenic activity by regulating the PKA-LKB1-AMPK-SRF pathway by interacting with angiotensin II receptor, type 1. We also show that RASAL1-deficient mice are more susceptible to liver fibrosis. These data demonstrate that deregulated RASAL1 expression levels and the affected downstream intracellular signaling are central mediators of perpetuated HSC activation and fibrogenesis in the liver.Liver fibrosis, leading to cirrhosis and liver failure, can occur after chronic liver injury. The transition of hepatic stellate cells (HSCs) from quiescent cells into proliferative and fibrogenic cells is a central event in liver fibrosis. Here, we show that RAS protein activator like-1 (RASAL1), a RAS-GTPase-activating protein, which switches off RAS activity, is significantly decreased during HSC activation, and that HSC activation can be antagonized by forced expression of the RASAL1 protein. We demonstrate that RASAL1 suppresses HSC proliferation by regulating the Ras-MAPK pathway, and that RASAL1 suppresses HSC fibrogenic activity by regulating the PKA-LKB1-AMPK-SRF pathway by interacting with angiotensin II receptor, type 1. We also show that RASAL1-deficient mice are more susceptible to liver fibrosis. These data demonstrate that deregulated RASAL1 expression levels and the affected downstream intracellular signaling are central mediators of perpetuated HSC activation and fibrogenesis in the liver.

Hepatitis B virus pathogenesis: Fresh insights into hepatitis B virus RNA

Hepatitis B virus (HBV) is still a worldwide health concern. While divergent factors are involved in its pathogenesis, it is now clear that HBV RNAs, principally templates for viral proteins and viral DNAs, have diverse biological functions involved in HBV pathogenesis. These functions include viral replication, hepatic fibrosis and hepatocarcinogenesis. Depending on the sequence similarities, HBV RNAs may act as sponges for host miRNAs and may deregulate miRNA functions, possibly leading to pathological consequences. Some parts of the HBV RNA molecule may function as viral-derived miRNA, which regulates viral replication. HBV DNA can integrate into the host genomic DNA and produce novel viral-host fusion RNA, which may have pathological functions. To date, elimination of HBV-derived covalently closed circular DNA has not been achieved. However, RNA transcription silencing may be an alternative practical approach to treat HBV-induced pathogenesis. A full understanding of HBV RNA transcription and the biological functions of HBV RNA may open a new avenue for the development of novel HBV therapeutics.

Circular RNA and exosomes in pancreatic cancer progression

Circular RNA (circRNA) is a type of noncoding RNA that forms a covalently closed continuous loop. CircRNAs were discovered in the 1980s but were thought to be an artifact of aberrant RNA splicing or specific to a few pathogens such as hepatitis delta virus (1). The development of next-generation sequencing and bioinformatics tools has led to the discovery of numerous endogenous circRNAs, the expression of which is considerably higher than previously thought.

Inhibition of HBV transcription from cccDNA with nitazoxanide by targeting the HBx–DDB1 interaction

Background & Aims Hepatitis B virus (HBV) infection is a major health concern worldwide. Although currently used nucleos(t)ide analogs efficiently inhibit viral replication, viral proteins transcribed from the episomal viral covalently closed circular DNA (cccDNA) minichromosome continue to be expressed long-term. Because high viral RNA or antigen loads may play a biological role during this chronicity, the elimination of viral products is an ultimate goal of HBV treatment. HBV regulatory protein X (HBx) was recently found to promote transcription of cccDNA with degradation of Smc5/6 through the interaction of HBx with the host protein DDB1. Here, this protein–protein interaction was considered as a new molecular target of HBV treatment. Methods To identify candidate compounds that target the HBx–DDB1 interaction, a newly constructed split luciferase assay system was applied to comprehensive compound screening. The effects of the identified compounds on HBV transcription and cccDNA maintenance were determined using HBV minicircle DNA, which mimics HBV cccDNA, and the natural HBV infection model of human primary hepatocytes. Results We show that nitazoxanide (NTZ), a thiazolide anti-infective agent that has been approved by the FDA for protozoan enteritis, efficiently inhibits the HBx–DDB1 protein interaction. NTZ significantly restores Smc5 protein levels and suppresses viral transcription and viral protein production in the HBV minicircle system and in human primary hepatocytes naturally infected with HBV. Conclusions These results indicate that NTZ, which targets an HBV-related viral–host protein interaction, may be a promising new therapeutic agent and a step toward a functional HBV cure.

A tiny but crucial player bridging microbes and colonic carcinogenesis

Colorectal cancer (CRC) is one of the most common malignancies in the world (1). The probability of suffering from CRC is approximately 4–5%, and the risk of developing CRC is associated with characteristics such as age, chronic disease history, and lifestyle (2). CRC is caused by mutations in oncogenes, tumor-suppressor genes, and genes related to DNA repair mechanisms. The underlying pathogenic mechanisms are threefold; namely, chromosomal instability (CIN), microsatellite instability (MSI), and CpG island methylator phenotype (CIMP). In CRC, common mutations, chromosomal changes, and translocations reportedly affect important intracellular signaling pathways [WNT, mitogen activated protein kinase (MAPK)/phosphoinositide 3-kinase (PI3K), transforming growth factor (TGF)-β, and TP53] (2). In addition to genetic mutations, alterations in non-coding RNAs, such as microRNAs, also contribute to carcinogenesis.

Sa1097 Analysis of Weekend Admission on Upper Gastrointestinal Bleeding; Is Weekend Effect Demonstrated in Japan?

Background and Aims: Whether weekend admission influences the mortality of upper gastrointestinal bleeding(UGIB) remains unclear in Japan. In Europe and North-America, some previous studies identified worse outcomes of weekend admission, however the opposite results were reported from Hong-Kong, Korea and Taiwan. The outcomes may vary considerably between each nation. This study was conducted to assess the weekend effect in patients with UGIB on the basis of a 10-year single-center experience in Japan. Methods and Patients:595 hospitalized patients, who were diagnosed with UGIB between January 2004 and March 2014, were enrolled. We divided those patients into two groups, variceal and nonvariceal UGIB. Bivariate analyses and multivariate logistic regression models were used to evaluate predicting variables of the in-hospital mortality, included patient characteristics, waiting time for endoscopy, and weekend admission. Results: 595 patients consisted of 484 nonvariceal and 111 variceal UGIB. 169 out of 484 Patients with nonvariceal UGIB were weekend admission and had similar mortality rates compared to the weekday group (2.96% vs 2.54%;odds ratio[OR],1.17;confidence interval[CI],0.38-3.63; P=0.79). The waiting time for endoscopy was also not different (9.97 hours versus 9.19 hours, P=0.55). There was no statistical difference in baseline characteristics. In the multivariate logistic regression model, mortality was correlated with Blatchford score ([OR],1.32 per point;[CI],1.05-1.72;P= 0.015) and waiting time to endoscopy ([OR],1.04 per hour;[CI],1.009-1.07; P=0.014). 34 out of 111 Patients with variceal UGIB were weekend admission and had relatively higher mortality rates compared to the weekday group (17.7% vs 10.4%;[OR],1.85;[CI],0.595.81;P=0.29), but not significant. The waiting time for endoscopy was not different (3.35 hours versus 5.3 hours, P =0.09). There was no statistical difference in baseline characteristics, except Child-Pugh scores. Child-Pugh scores of patients with variceal UGIB on weekend admission were significantly higher than those on weekday admission (9.29 vs 8.3; P=0.01). In the multivariate logistic regression model, mortality was correlated with Child-Pugh scores ([OR],1.83 per point;[CI],1.16-3.22; P=0.008). Conclusion:In Japan, quality of care did not appear to differ between week/weekend admission of patients with UGIB and weekend effect was not demonstrated in this study. Patient characteristics and waiting time for endoscopy were correlated with the risk of the in-hospital mortality.