Megumi Kimura

Prevalence and characteristics of naturally occurring sofosbuvir resistance-associated variants in patients with hepatitis C virus genotype 1b infection.

Sofosbuvir (SOF), a nucleotide analog pro‐drug, targets hepatitis C virus (HCV) NS5B polymerase and shows potential for treating HCV infection, given its high efficacy and good barrier to resistance. However, in addition to the rare resistant‐associated variant (RAV) of non‐structural protein NS5B S282T, several new potential RAVs of SOF have been reported, especially related to HCV genotype 1b. However, the prevalence and characteristics of these RAVs have not been clarified.

Safety and efficacy of daclatasvir and asunaprevir in hepatitis C virus‐infected patients with renal impairment

Hepatitis C virus (HCV) infection is a risk factor for end‐stage renal disease, renal graft failure, and hemodialysis patient mortality. However, the efficacy of direct‐acting antiviral therapy for HCV‐infected patients with renal impairment is unclear. Additionally, the promising NS5B inhibitor sofosbuvir has not been recommended for patients with severe renal impairment. In this prospective, multicenter study, we evaluated the efficacy and safety of daclatasvir and asunaprevir combination therapy, with a focus on patients with renal impairment.

Comparing the risk of hepatitis B virus reactivation between direct-acting antiviral therapies and interferon-based therapies for hepatitis C

Hepatitis B virus (HBV) reactivation has been reported during antihepatitis C treatment in patients with hepatitis C virus (HCV) and HBV co‐infection. We aimed to evaluate the frequency and risk factors of HBV reactivation during anti‐HCV therapy and compared those between interferon (IFN)‐free direct‐acting antiviral (DAA) therapies and IFN‐based therapies. Three hundred and twenty‐two patients with HCV infection receiving anti‐HCV therapy were retrospectively screened. The baseline HBV infection statuses of all eligible patients and the HBV‐DNA level of all patients with current or previous HBV infection were examined at the end of treatment. In patients with baseline anti‐HBs positivity, changes in anti‐HBs titre were evaluated. Of 287 patients who met the inclusion criteria, 157 had current (n=4) or previous (n=153) HBV infection; 85 were treated with IFN‐free DAA therapies and 72 were treated with IFN‐based therapies. Six patients experienced HBV reactivation (n=2) or HBV reappearance (n=4) after IFN‐free DAA therapies, while no patient developed HBV reactivation after IFN‐based therapies. The risk factors of HBV reactivation or reappearance were DAA therapies and a reduction in anti‐HBs titre to <12 mIU mL−1 by the end of treatment. The decline changes of anti‐HBs titre were significantly higher in patients treated with DAA therapies. Although HBV reactivation hepatitis was not observed, three of four patients with HBV reactivation or reappearance after achieving HCV eradication had viremia 8 weeks after completion of therapy. A significant proportion of patients develop HBV reactivation or reappearance without hepatitis after IFN‐free DAA therapies. Low levels of anti‐HBs and their decrease to <12 mIU mL−1 after treatment are significant risk factors for HBV reactivation or reappearance.

Hepatitis B virus X protein impairs α-interferon signaling via up-regulation of suppressor of cytokine signaling 3 and protein phosphatase 2A.

Hepatitis B Virus (HBV) causes liver cirrhosis and hepatocellular carcinoma. Standard therapy includes treatment with interferon (IFN); however, its efficacy is limited. HBV has been reported to impair IFN signaling; however, the mechanism is unclear. Here, the relationship between HBV X protein (HBx) and IFN signaling was investigated by establishing HepG2 cells, stably expressing HBx (HepG2/HBx) via retrovirus‐mediated gene transfer. Subsequently, IFN negative‐regulator expression and its mechanism were studied. HepG2/HBx cells showed reduced expression of IFN‐stimulated genes and expressed higher levels of suppressor of cytokine signaling 3 (SOCS3) and protein phosphatase 2A (PP2A) suppressor compared with control cells. Knockdown of SOCS3 and PP2A restored IFN sensitivity. Moreover, HepG2/HBx cells showed higher phosphorylation levels of signal transducers and activators of transcription 3 and endoplasmic reticulum stress, which are inducers of SOCS3 and PP2A, respectively. Additionally, HBx‐knockdown restored IFN sensitivity in HepG2.2.15.7 cells. It was also confirmed that SOCS3 and PP2A expression levels were up‐regulated in the liver of patients with HBV infection. The results of this study demonstrated that HBx impairs IFN signaling via increased expression of SOCS3 and PP2A, a novel mechanistic insight, providing a potential therapeutic target to enhance the efficiency of IFN therapy. J. Med. Virol. 89:267–275, 2017.

Fibroblast growth factor-2–mediated FGFR/Erk signaling supports maintenance of cancer stem-like cells in esophageal squamous cell carcinoma

In esophageal squamous cell carcinoma (ESCC), a subset of cells defined by high expression of CD44 and low expression of CD24 has been reported to possess characteristics of cancer stem-like cells (CSCs). Novel therapies directly targeting CSCs have the potential to improve prognosis of ESCC patients. Although fibroblast growth factor-2 (FGF-2) expression correlates with recurrence and poor survival in ESCC patients, the role of FGF-2 in regulation of ESCC CSCs has yet to be elucidated. We report that FGF-2 is significantly upregulated in CSCs and significantly increases CSC content in ESCC cell lines by inducing epithelial-mesenchymal transition (EMT). Conversely, the FGFR inhibitor, AZD4547, sharply diminishes CSCs via induction of mesenchymal-epithelial transition. Further experiments revealed that MAPK/Erk kinase (Mek)/extracellular signal-regulated kinases (Erk) pathway is crucial for FGF-2-mediated CSC regulation. Pharmacological inhibition of FGF receptor (FGFR)-mediated signaling via AZD4547 did not affect CSCs in Ras mutated cells, implying that Mek/Erk pathway, downstream of FGFR signaling, might be an important regulator of CSCs. Indeed, the Mek inhibitor, trametinib, efficiently suppressed ESCC CSCs even in the context of Ras mutation. Consistent with these findings in vitro, xenotransplantation studies demonstrated that inhibition of FGF-2-mediated FGFR/Erk signaling significantly delayed tumor growth. Taken together, these findings indicate that FGF-2 is an essential factor regulating CSCs via Mek/Erk signaling in ESCC. Additionally, inhibition of FGFR and/or Mek signaling represents a potential novel therapeutic option for targeting CSCs in ESCC.

Safety and efficacy of sofosbuvir and ribavirin for genotype 2 hepatitis C Japanese patients with renal dysfunction: SOF/RBV for patients with renal dysfunction

The safety and efficacy of sofosbuvir (SOF) and ribavirin (RBV) have not been well clarified in patients with renal dysfunction because clinical trials have not included such patients. We evaluated the safety and efficacy of SOF and RBV for genotype 2 hepatitis C virus (HCV)‐infected patients with renal dysfunction.

Anti-adipogenic and antiviral effects of l-carnitine on hepatitis C virus infection.

Hepatitis C virus (HCV) has been reported to hijack fatty acid metabolism in infected hepatocytes, taking advantage of lipid droplets for virus assembly. In this study, we analyzed the anti‐HCV activity of l‐carnitine, a substance involved in the transport of fatty acids into mitochondria. JFH‐1 or HCV replicon‐transfected Huh7.5.1 cells were treated with or without l‐carnitine to examine its anti‐HCV effects. The effects of l‐carnitine on HCV entry, HCV‐induced adipogenesis and lipid droplet formation, and HCV‐induced oxidative stress were examined. Treatment of JFH‐1‐infected cells with l‐carnitine inhibited HCV propagation in a concentration‐dependent manner. In contrast, l‐carnitine had no anti‐HCV activity in the HCV replicon system, which is lacking viral assembly. In addition, l‐carnitine did not affect HCV entry. However, l‐carnitine treatment decreased intracellular lipid droplets, which are crucial for HCV assembly in JFH‐1‐infected cells. The expression level of CPT‐1 was decreased in JFH‐1‐infected cells, and l‐carnitine treatment restored this expression. HCV‐infected cells exhibited increased production of reactive oxygen species and glutathione oxidation. l‐carnitine decreased oxidative stress induced by JFH‐1‐infection, as shown by glutathione/glutathione disulfide assays and MitoSOX staining. l‐carnitine exhibited anti‐HCV activity, possibly by inhibiting HCV assembly and through its anti‐adipogenic activity in HCV‐infected cells. Moreover, l‐carnitine has antioxidant properties in HCV‐infected hepatocytes. Overall, these results indicated that l‐carnitine may be an effective adjunctive agent in antiviral therapies to treat chronic hepatitis C. J. Med. Virol. 89:857–866, 2017.

Add-on effects of fluvastatin in simeprevir/pegylated-interferon/ribavirin combination therapy for patients with genotype 1 hepatitis C virus infection: A randomized controlled study: FLV add-on SMV/Peg-IFN/RBV therapy

The Japan Society of Hepatology guidelines indicate that hepatitis C virus (HCV) protease inhibitor combination therapy with simeprevir (SMV), pegylated‐interferon (Peg‐IFN), and ribavirin (RBV) is a therapeutic option for patients who fail to respond to a direct direct‐acting antiviral‐containing regimen. However, treatment outcomes have room for improvement. Fluvastatin (FLV) add‐on treatment in Peg‐IFN and RBV combination therapy for HCV‐infected patients significantly improved the sustained virologic response (SVR), but the add‐on effect of FLV on SMV combination therapy is not well understood.

L‐Carnitine Suppresses Loss of Skeletal Muscle Mass in Patients With Liver Cirrhosis

Liver cirrhosis (LC) is a major cause of secondary sarcopenia. Sarcopenia makes the prognosis worse; thus, novel therapeutic options for sarcopenia in patients with LC are urgently required as they are currently limited. In this retrospective study, 158 patients with LC were screened, and 35 of those patients who were treated with L‐carnitine for more than 6 months and for whom skeletal muscle mass changes could be evaluated by computer tomography were enrolled. Of the 158 patients, 79 patients who did not receive L‐carnitine supplementation served as controls. Cases and controls were propensity score matched for age, sex, presence of hepatocellular carcinoma, and branched chain amino acid administration, and changes in skeletal muscle mass and clinical data were compared. The 35 patients who received L‐carnitine supplementation and 35 propensity score‐matched patients who did not receive carnitine supplementation comprised the final enrollment. Compared with control patients, patients who received L‐carnitine had significantly worse liver function, which is associated with rapid progress of skeletal muscle depletion. However, loss of skeletal muscle mass was significantly suppressed in patients receiving L‐carnitine, and a significant effect was observed in patient subgroups stratified by age, sex, presence of hepatocellular carcinoma, and branched chain amino acid administration. The change ratios of most laboratory data, including vitamin D and insulin‐like growth factor 1 levels, were similar in the two groups, but ammonia levels were significantly less in those receiving L‐carnitine. However, even in patients receiving L‐carnitine but not showing an ammonia decrease, loss of skeletal muscle was significantly suppressed. Conclusion: L‐carnitine suppresses loss of skeletal muscle mass and may therefore be a novel therapeutic option for sarcopenia in patients with LC. (Hepatology Communications 2018; 00:000‐000)

Combination of neutrophil-to-lymphocyte ratio and early des-γ-carboxyprothrombin change ratio as a useful predictor of treatment response for hepatic arterial infusion chemotherapy against advanced hepatocellular carcinoma.

Hepatic arterial infusion chemotherapy (HAIC) is a potent therapeutic option for advanced hepatocellular carcinoma (HCC). However, there are few known predictive factors of treatment response to HAIC. We clarified the most accurate predictive factors early on in treatment.