Amir Shlomai

New therapies for chronic hepatitis B

Approximately 350 million people worldwide are chronically infected with hepatitis B virus (HBV), representing a significant public health challenge. Nucleos/tide analogues (NUCs) and interferon alpha (IFNα), the current standard of care for chronic infection, aim at preventing progression of the disease to cirrhosis, hepatocellular carcinoma (HCC) and death. However, in contrast to the case of hepatitis C virus infection, in which novel antiviral drugs cure the vast majority of treated patients, in regard to HBV, cure is rare due to the unusual persistence of viral DNA in the form of covalently closed circular DNA (cccDNA) within the nucleus of infected cells. Available therapies for HBV require lifelong treatment and surveillance, as reactivation frequently occurs following medication cessation and the occurrence of HCC is decreased but not eliminated, even after years of successful viral suppression. Progress has been made in the development of new therapeutics, and it is likely that only a combination of immune modulators, inhibitors of gene expression and replication and cccDNA‐targeting drugs will eradicate chronic infection. This review aims to summarize the state of the art in HBV drug research highlighting those agents with the greatest potential for success based on in vitro as well as on data from clinical studies.

Dipeptidyl Peptidase 4-Deficient Rats Have Improved Bile Secretory Function in High Fat Diet-Induced Steatosis

Background/AimsRodent obesity models have been shown to display impaired bile secretory functions. We have shown that glucagon-like peptide 1 (GLP-1) attenuates hepatic lipogenesis, and in the present study we investigated whether GLP-1 also improves high fat diet-associated cholestatic injury.MethodsWild type (WT) and dipeptidyl peptidase 4-deficient rats (DPP4-) with chronic elevated serum levels of active GLP-1 were fed regular chow and a Western diet for 2xa0months. Primary hepatocytes were used to assess GLP-1 effects on mRNA expression and transcription of genes encoding bile acid synthesis enzymes and transporters.ResultsDPP4- exhibited attenuated liver injury as expressed by lower serum AST and ALT after 2xa0months of a Western diet. In addition, DPP4- had better insulin sensitivity, lower serum triglycerides, cholesterol and bile acids. Hepatic expression of cyp7A1, the rate limiting enzyme in conversion of cholesterol into bile acids, was strongly attenuated in DPP4- fed with a Western diet. Moreover, hepatic expression of bile transporter, ABCB11, was increased, facilitating a higher rate of bile secretion. Mechanistically, we showed that GLP-1 directly reduced basal and LXR-induced cyp7A1 mRNA expression and suppressed cyp7A1 transcription in transient transfection assays in primary hepatocytes. However, GLP-1 and its analog exendin 4 also induced mRNA expression of bile acid transporter ABCC3 in primary rat hepatocyte cultures.ConclusionsOur data suggest that GLP-1 analogs may serve as a novel therapeutic drug to alleviate obesity-induced liver injury by reducing bile acid synthesis and improving liver bile secretory function.

Diagnostic and Prognostic Value of Thrombocytosis in Admitted Medical Patients

Introduction:Whether secondary thrombocytosis is a distinguishing clinical biomarker of various diseases, and whether it is an independent predictor of short-term outcome of admitted medical patients is unknown and has never been examined. Methods:A cohort of all 138 patients with secondary thrombocytosis (platelets count ≥ 5 x 105/&mgr;L) admitted to the department of medicine during the last 2 years was analyzed. Epidemiological and clinical data, and the final diagnosis and outcome were recorded and compared with a cohort of 684 consecutive admitted patients without thrombocytosis. Results:Thrombocytosis was not a non-specific marker of inflammation, because uncomplicated infections and most admission causes were not associated with thrombocytosis, except for inflammatory rheumatic diseases (6% versus 1%), along with anemia (9.4% versus 2.5%) and tumor comorbidity (25% versus 14%). In contrast, thrombocytosis was a distinguishing biomarker for severe pyogenic infections, especially empyema (5% vs. 0%), any abscesses (14% versus 3%), and soft tissue infections (7% versus 3%). Moreover, the thrombocytosis group had significantly more admission days, infections (45% versus 33%), sepsis (21% versus 6%), in-hospital major complications (15% versus 3%) and mortality (19% versus 5%). Finally, thrombocytosis was found to be an independent predictor of mortality, in a multivariate regression analysis. Conclusions:Thrombocytosis is not a simple marker of inflammation. Its presence warrants thorough investigation for the presence of severe underlying disease, mostly complicated pyogenic infections, inflammatory rheumatic diseases and malignancy. Moreover, thrombocytosis is a marker for major complications and is an independent predictor of mortality in admitted medical patients.

Advances and Challenges in Studying Hepatitis B Virus In Vitro

Hepatitis B virus (HBV) is a small DNA virus that infects the liver. Current anti-HBV drugs efficiently suppress viral replication but do not eradicate the virus due to the persistence of its episomal DNA. Efforts to develop reliable in vitro systems to model HBV infection, an imperative tool for studying HBV biology and its interactions with the host, have been hampered by major limitations at the level of the virus, the host and infection readouts. This review summarizes major milestones in the development of in vitro systems to study HBV. Recent advances in our understanding of HBV biology, such as the discovery of the bile-acid pump sodium-taurocholate cotransporting polypeptide (NTCP) as a receptor for HBV, enabled the establishment of NTCP expressing hepatoma cell lines permissive for HBV infection. Furthermore, advanced tissue engineering techniques facilitate now the establishment of HBV infection systems based on primary human hepatocytes that maintain their phenotype and permissiveness for infection over time. The ability to differentiate inducible pluripotent stem cells into hepatocyte-like cells opens the door for studying HBV in a more isogenic background, as well. Thus, the recent advances in in vitro models for HBV infection holds promise for a better understanding of virus-host interactions and for future development of more definitive anti-viral drugs.

AST to Platelet Ratio Index and fibrosis 4 calculator scores for non-invasive assessment of hepatic fibrosis in patients with non-alcoholic fatty liver disease

BACKGROUND & AIMSnLiver fibrosis is the single most important prognostic factor in patients with non-alcoholic fatty liver disease (NAFLD). The predictive value of the AST to Platelet Ratio Index (APRI) score, originally developed for fibrosis assessment in hepatitis C virus (HCV) patients, is much less known in the context of NAFLD patients.nnnMETHODSnWe retrospectively compared the performance of APRI and fibrosis 4 calculator (FIB-4) scores in NAFLD patients with documented liver biopsies, to their performance in chronic HCV patients.nnnRESULTSn153 patients with biopsy-proven NAFLD and 297 patients with biopsy-proven chronic HCV infection were included. The APRI score was a good predictor for advanced fibrosis in NAFLD patients (area under the ROC curve 0.8307) although it was modestly inferior as compared to the well-validated FIB-4 score (area under the ROC curve 0.8959). The predictive value of APRI score in NALFD patients was inferior as compared to its predictive value in HCV patients (area under the ROC curve of 0.8307 versus 0.9965). In contrast to FIB-4, APRI score was not a good discriminator between intermediate stages of fibrosis in NAFLD patients.nnnCONCLUSIONSnAPRI and Fib-4 scores are reasonable tools to allocate NAFLD patients with advanced fibrosis. FIB-4 may better discriminate between intermediate fibrosis stages.

Patients' Age Rather Than Model of End-Stage Liver Disease Score Predicts Survival After Liver Transplantation.

AbstractBackgroundnThe model of end-stage liver disease (MELD) score is the standard tool for prioritizing patients awaiting liver transplantation. There is currently no definite high cutoff score reflecting disease severity that might exclude patients from transplantation. Furthermore, the age limit that used to disqualify patients from eligibility to transplantation was recently withdrawn in several countries.nAimsnThe aims of this study were to assess the effects of MELD score and age at time of transplantation on patients’ short- and long-term survival.MethodsWe conducted a retrospective single-center study on a cohort of patients transplanted for the first time due to non-fulminant liver failure.ResultsFour hundred and seventeen patients (mean age 50.2xa0years, 63% males) who underwent liver transplantation for the first time were included. Both higher patients’ and donors’ age were significantly associated with increased long-term mortality (pxa0=xa00.007, 95% CI 1.006–1.038 for patient age, pxa0=xa00.02, 95% CI 1.002–1.023 for donor age). Patients’ age remained significantly associated with survival at 1xa0year post-transplantation, as well. We found no association between higher MELD score at transplantation and long-term mortality (pxa0=xa00.189, 95% CI 0.99–1.051) irrespective of patients’ age. Specifically, when patients were divided according to their MELD score at transplantation (MELDxa0<xa015, MELD 15–25 and MELDxa0>xa025), no significant differences in long-term survival were detected between these three subgroups. Results did not differ significantly in a subgroup analysis of patients without hepatocellular carcinoma at the time of transplantation.ConclusionsPatients’ and donors’ age rather than patients’ MELD score at transplantation determine survival following liver transplantation.

Inhibition of pMAPK14 Overcomes Resistance to Sorafenib in Hepatoma Cells with Hepatitis B Virus

Hepatitis B virus (HBV) targets the liver and is a major driver for liver cancer. Clinical data suggest that HBV infection is associated with reduced response to treatment with the multi-kinase inhibitor sorafenib, the first available molecularly targeted anti-hepatocellular carcinoma (HCC) drug. Given that Raf is one of the major targets of sorafenib, we investigated the activation state of the Raf-Mek-Erk pathway in the presence of HBV and in response to sorafenib. Here we show that hepatoma cells with replicating HBV are less susceptible to sorafenib inhibitory effect as compared to cells in which HBV expression is suppressed. However, although HBV replication is associated with increased level of pErk, its blockade only modestly augments sorafenib effect. In contrast, the phosphorylated form of the pro-oncogenic Mitogen-Activated Protein Kinase 14 (pMAPK14), a protein kinase that was recently linked to sorafenib resistance, is induced in sorafenib-treated hepatoma cells in association with HBV X protein expression. Knocking down pMAPK14 results in augmentation of the therapeutic efficacy of sorafenib and largely alleviates resistance to sorafenib in the presence of HBV. Thus, this study suggests that HBV promotes HCC resistance to sorafenib. Combining pMAPK14 inhibitors with sorafenib may be beneficial in patients with HBV-associated HCC.

The antiviral protein Viperin suppresses T7 promoter dependent RNA synthesis–possible implications for its antiviral activity

Viperin is a multifunctional interferon-inducible broad-spectrum antiviral protein. Viperin belongs to the S-Adenosylmethionine (SAM) superfamily of enzymes known to catalyze a wide variety of radical-mediated reactions. However, the exact mechanism by which viperin exerts its functions is still unclear. Interestingly, for many RNA viruses viperin was shown to inhibit viral RNA accumulation by interacting with different viral non-structural proteins. Here, we show that viperin inhibits RNA synthesis by bacteriophage T7 polymerase in mammalian cells. This inhibition is specific and occurs at the RNA level. Viperin expression significantly reduced T7-mediated cytoplasmic RNA levels. The data showing that viperin inhibits the bacteriophage T7 polymerase supports the conservation of viperin’s antiviral activity between species. These results highlight the possibility that viperin might utilize a broader mechanism of inhibition. Accordingly, our results suggest a novel mechanism involving polymerase inhibition and provides a tractable system for future mechanistic studies of viperin.

Noninvasive scoring systems predict hepatic and extra-hepatic cancers in patients with nonalcoholic fatty liver disease

Background Liver fibrosis predicts liver-related morbidity and mortality in patients with non-alcoholic fatty liver disease (NAFLD). Non-invasive scores correlate with the degree of liver fibrosis in these patients. Aims and methods To investigate the accuracy of noninvasive scoring systems in predicting long-term outcomes and cancer incidence of patients with NAFLD, we performed a single-center retrospective study of patients with biopsy proven NAFLD. Mean follow up period was 100 months. Outcomes included liver-related complications, hospitalizations, overall mortality and the development of any malignancies. Results 32 patients had advanced fibrosis (F3-F4) per biopsy at baseline and 121 patients had mild to moderate fibrosis (F0-F2). Both advanced histologic fibrosis stage as well as higher non-invasive scores predicted repeated hospitalizations and longer hospitalization stays. In a multivariate analysis, liver fibrosis (p = 0.002), FIB-4 score (p<0.001), NFS (p<0.001) but not APRI score (p = 0.07) were predictors of overall mortality, and the occurrence of malignancies was associated with higher APRI (p<0.001), FIB-4 (p<0.001) and NFS (p = 0.008) scores, but not with advanced fibrosis, as determined by liver biopsy (p = 0.105). Conclusions In NAFLD patients, noninvasive scoring systems are good predictors of morbidity and mortality and may have an additive value in predicting the development of hepatic and extra-hepatic cancers.

The effect of cause, timing, kidney function recovery, and recurrent events on the prognosis of acute kidney injury in kidney transplant recipients

To assess the incidence of acute kidney injury (AKI) and its common etiologies in kidney transplant recipients and the effect of AKIs characteristics on graft survival.