PegIFN-α2a for the treatment of chronic hepatitis B and C: a 10-year history

Chronic HBV and HCV are progressive diseases leading to cirrhosis and liver transplantation. Persistent viral eradication or suppression can positively affect the natural course of the infection, by preventing disease progression. Since its introduction more than 30 years ago, IFN-α has represented the foundation of HBV and, lately, anti-HCV treatment. Pegylation of the IFN-α molecule (PegIFN-α2a) has provided improvements in both efficacy and administration schedule, thus becoming part of the standard-of-care regimen for HCV and HBV therapy in the last 10 years. Currently, treatment of finite duration with PegIFN-α2a may achieve a sustained virological response off-treatment and HBsAg seroconversion. PegIFN-α2a will most likely remain the backbone of HCV treatment for the next few years, despite the availability of direct-acting antivirals that are expected to improve cure rates. However, many efforts are concentrated on developing new compounds, with the goal of administrating all oral regimens and eliminating PegIFN from anti-HCV treatment.     

Mechanism of interaction of human mitochondrial DNA polymerase γ with the novel nucleoside reverse transcriptase inhibitor 4'-ethynyl-2-fluoro-2'-deoxyadenosine indicates a low potential for host toxicity

The potent antiretroviral 4'-ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a promising experimental agent for treating HIV infection. Pre-steady-state kinetics were used to characterize the interaction of EFdA-triphosphate (EFdA-TP) with human mitochondrial DNA polymerase γ (Pol γ) to assess the potential for toxicity. Pol γ incorporated EFdA-TP 4,300-fold less efficiently than dATP, with an excision rate similar to ddATP. This strongly indicates EFdA is a poor Pol γ substrate, suggesting minimal Pol γ-mediated toxicity, although this should be examined under clinical settings.     

Effects of aspirin on the expression of nuclear factor-κB in a rat model of acute pulmonary embolism

BACKGROUND:

Acute pulmonary embolism (APE) is a disorder involving the pulmonary circulation resulting from a blockage of the pulmonary artery. The present study aimed to investigate the effects of aspirin on the nuclear factor-κB (NF-κB) activity in a rat model of APE.

METHODS:

A total of 108 healthy male Sprague-Dawley rats were randomly assigned into six groups (n=18 rats per group): control group, sham operation group, APE model group, and low-, medium- and high-dose aspirin groups. Six, 24, and 72 hours after the induction of APE, rats in the low-, medium- and high-dose aspirin groups were given aspirin at a respective daily dose of 150, 300, and 600 mg/kg by gavage for three consecutive days. Rats in the other groups were treated with equal volumes of normal saline. Six rats in each group were anesthetized with 10% chloral hydrate solution at each time point, and then the lung tissues were collected and analyzed using immunohistochemical staining.

RESULTS:

Positive immunohistochemical staining was present in the bronchial epithelial cells, alveolar cells, macrophages, and surrounding bronchial smooth muscle cells. When compared with the APE model group, the number of positive cells was significantly lower in the other groups at each time point (P<0.001). Statistically significant differences were also observed among the aspirin-treated groups at 6 hours (P<0.05, P<0.001). Compared with the APE model group, NF-κB protein expression was reduced in the other groups at each time point (P<0.05, P<0.001). Rats from the APE model group had thrombosis, damaged alveolar walls, and pulmonary hemorrhage, along with different degrees of inflammatory cellular infiltration at each time point. However, pathological changes such as pulmonary hemorrhage and infiltration of inflammatory cells were attenuated after the aspirin treatment.

CONCLUSION:

Aspirin can significantly inhibit NF-κB activity in the lung of rats with APE in a dose-dependent manner, and can alleviate lung injury after APE.KEY WORDS: Aspirin, Acute pulmonary embolism, Nuclear factor-κB     

Quantitative assessment of left ventricular myocardial work in chronic kidney disease patients by a novel non-invasive pressure–strain loop analysis method

The International Journal of Cardiovascular Imaging - This study aimed to quantitatively evaluate myocardial work (MW) in advanced stage 3–5 chronic kidney disease (CKD) by a novel...     

Effect of thymosin-α(1) on T-helper 1 cell and T-helper 2 cell cytokine synthesis in patients with hepatitis B virus e antigen-positive chronic hepatitis B

Thymosin-α(1) (TA(1)) has been shown to be effective treatment for chronic hepatitis B virus (HBV) infection. This study investigated the immune response after TA(1) monotherapy in 25 HBV e antigen (HBeAg)-positive patients randomized to receive either 1.6 mg active TA(1) (group A), 1.6 mg recombinant TA(1) (group B) or 3.2 mg recombinant TA(1) (group C) monotherapy for 52 weeks. The percentages of T-helper 1 (T(h)1) cytokine-producing T-cells (interleukin-2 [IL-2], interferon-γ [IFN-γ], tumour necrosis factor-α) and T(h)2 cytokine-producing T-cells (IL-4) were analysed using flow cytometry. In all patients treated with TA(1), cytokine levels and the proportion of peripheral blood mononuclear cells producing these cytokines were significantly increased, compared with baseline and healthy controls. The proportions of each cytokine-producing cell increased gradually over time and were restored to normal levels, and proportions of IFN-γ and IL-4-producing cells reached higher levels than in normal (healthy) controls. The results showed that treatment with TA(1) increased cytokine production, especially IFN-γ, and higher-dose TA(1) exhibited better efficacy against HBV, compared with other treatments studied.     

Aspartate aminotransferase to platelet ratio index – a reliable predictor of therapeutic efficacy and improvement of Ishak score in chronic hepatitis B patients treated with nucleoside analogues

Background No studies have investigated the predictive and monitoring efficacy of aspartate aminotransferase to platelet ratio index in chronic hepatitis B patients undergoing antiviral therapy based on paired Ishak biopsies pre- and post-treatment. We evaluated the efficacy of aspartate aminotransferase to platelet ratio index in monitoring fibrosis improvement in chronic hepatitis B patients treated with nucleoside analogue or interferon. Methods Pre- and post-treatment Ishak fibrosis scores of 86 nucleoside-analogue- and 42 interferon-treated patients were retrospectively analyzed. The area under the receiver operating characteristic curve was calculated. Results In nucleoside-analogue-treated patients, the area under the receiver operating characteristic curve was 0.80 and 0.91 when aspartate aminotransferase to platelet ratio index was used to diagnose fibrosis and cirrhosis, respectively. When the decreased magnitude of aspartate aminotransferase to platelet ratio index was ≥ 0.35, the sensitivity and specificity of predicting fibrosis improvement were 75.8% and 75.0%, respectively. The area under the receiver operating characteristic curve was 0.53 when aspartate aminotransferase to platelet ratio index was used to diagnose fibrosis in 20 interferon-treated patients, while an insufficient patient number in the cirrhosis group prevented the calculation of the area under the receiver operating characteristic curve. The same is true for the remaining 22 interferon-treated patients. Conclusions Our study is the first to demonstrate the aspartate aminotransferase to platelet ratio index as a reliable marker in diagnosing and monitoring fibrosis improvement in nucleoside-analogue-treated patients based on paired Ishak biopsies pre- and post-treatment, but the test is not applicable in interferon therapy.     

Cardiovascular disease is associated with high-fat-diet-induced liver damage and up-regulation of the hepatic expression of hypoxia-inducible factor 1α in a rat model

CVD (cardiovascular disease) is associated with abnormal liver enzymes, and NAFLD (non-alcoholic fatty liver disease) is independently associated with cardiovascular risk. To gain insights into the molecular events underlying the association between liver enzymes and CVD, we developed an HFD (high-fat diet)-induced NAFLD in the SHR (spontaneously hypertensive rat) and its control WKY (Wistar-Kyoto) rat strain. We hypothesized that hepatic induction of Hif1a (hypoxia-inducible factor 1α) might be the link between CVD and liver injury. Male SHRs (n=13) and WKY rats (n=14) at 16?weeks of age were divided into two experimental groups: standard chow diet and HFD (10?weeks). HFD-fed rats, irrespective of the strain, developed NAFLD; however, only HFD-SHRs had focus of lobular inflammation and high levels of hepatic TNFα (tumour necrosis factor α). SHRs had significantly higher liver weight and ALT (alanine aminotransferase) levels, irrespective of NAFLD. Liver abundance of Hif1a mRNA and Hif1α protein were overexpressed in SHRs (P<0.04) and were significantly correlated with ALT levels (R=0.50, P<0.006). This effect was not reverted by a direct acting splanchnic vasodilator (hydralazine). Angiogenesis may be induced by the HFD, but the disease model showed significantly higher hepatic Vegf (vascular endothelial growth factor) levels (P<0.025) even in absence of dietary insult. Hif1a mRNA overexpression was not observed in other tissues. Liver mRNA of Nr1d1 (nuclear receptor subfamily 1, group D, member 1; P<0.04), Ppara [Ppar (peroxisome-proliferatoractivated receptor) α; P<0.05], Pparg (Pparγ; P<0.001) and Sirt1 (Sirtuin 1; P<0.001) were significantly upregulated in SHRs, irrespective of NAFLD. Sirt1 and Hif1a mRNAs were significantly correlated (R=0.71, P<0.00002). In conclusion, CVD is associated with Hif1a-related liver damage, hepatomegaly and reprogramming of liver metabolism, probably to compensate metabolic demands.     

Pegylated-IFNα2a for HIV/hepatitis C virus coinfected patients: out with the old,in with the new

Introduction: Liver disease is a major burden in patients co-infected with HIV and hepatitis C virus (HCV). From the time of its approval, pegylated-IFNα-2a (pegIFN-α2a) has played a major role in treatment of HCV in HIV/HCV co-infection.

Areas covered: This article briefly summarizes the epidemiology of HCV/HIV co-infection, the pharmacokinetic, and pharmacodynamic properties of pegIFN-α2a. Results from clinical trials investigating therapies containing pegIFN-α2a for HIV/HCV co-infected patients will be discussed with a focus on efficacy and safety.

Expert opinion: PegIFN-α2a has improved rates of sustained virologic response for co-infected patients. In combination with direct-acting antivirals (DAA), the disparity between mono- and co-infected patients is beginning to disappear. For the first time, IFN-free regimens are available in clinical practice. It is unlikely that pegIFN-α2a will continue to be a critical component in treatments for HCV in the general co-infected population.     

β2-microglobulin, a novel biomarker of peripheral arterial disease, independently predicts aortic stiffness in these patients

Arterial stiffness is a prominent feature of vascular ageing and strongly predicts cardiovascular and total mortality. The β2-microglobulin, (β2M) a newly identified biomarker of peripheral arterial disease (PAD), is related to renal insufficiency, inflammatory and neoplastic diseases, but may also play a role in vascular dysfunction. However, the relationship between arterial stiffness and β2M has not been previously studied in patients with atherosclerosis. In the present study we examined a possible association between β2M and arterial stiffness in patients with PAD and in healthy subjects. Plasma β2M levels and parameters of arterial stiffness such as aortic pulse wave velocity (aPWV) and augmentation index (AIx) were measured in 66 patients with PAD and in 66 apparently healthy subjects. Plasma levels of β2M, aPWV and AIx were significantly increased in patients with PAD compared with controls (1858.1 ± 472.8 vs 1554.5 ± 277.9 μg/L, p < 0.001; 9.9 ± 2.2 m/s vs 7.6 ± 1.6 m/s, p < 0.001; 28 ± 8 vs 14 ± 11%, p < 0.001; respectively). There existed significant correlation between aPWV and β2M for the patient group (R = 0.47; p < 0.001), but not for the controls (R = 0.14; p = 0.26). In multivariate analysis, β2M remained independently associated with aPWV, fetuin-A, age and glomerular filtration rate in patients (R(2) = 0.5, p < 0.001). We found no relationship between β2M and AIx in either group. We demonstrated that among patients with PAD elevated plasma β2M levels were associated with higher aortic stiffness irrespective of cardiovascular disease risk factors. These data suggest that β2M may influence the pathogenesis of aortic stiffness in atherosclerosis.     

Expression of c‐kit protooncogen in hepatitis B virus‐induced chronic hepatitis,cirrhosis and hepatocellular carcinoma: has it a diagnostic role?

Aim: There are more than 350 million people worldwide chronically infected with hepatitis B virus (HBV), who are at high risk for the development of hepatitis, cirrhosis and hepatocellular carcinoma (HCC). Because of the conflicting results about c‐kit expression in HCC and the key role played by c‐kit in gastrointestinal stromal tumours (GIST) and other solid tumours, the aim of this study was to determine c‐kit expression in the course of hepatitis B infection. Materials and methods: Paraffin‐embedded tissues in Cukurova University Faculty of Medicine Department of Pathology between January 2002 and February 2006 were searched restrospectively to investigate this issue. We performed immunohistochemistry on biopsies of 125 patients with HBV infection, grouped as: mild, moderate and severe hepatitis, cirrhosis and HCC, 25 patients in each of them, using anti c‐kit monoclonal antibody. The severity of parenchymal inflammation and of interface hepatitis was semiquantitatively graded on a haematoxylin and eosin stained paraffin sections. Additionally, 50 more HCC, formed on HBV basis, were studied to determine the prevalence of c‐kit overexpression. Results: In cirrhotic liver, lower intensity of staining and rarely c‐kit positivity were present. The greatest number of the c‐kit positivity and higher intensity of staining was found in the livers of patients with severe hepatitis and HCC. In chronic hepatitis B infection, the staining intensity was parallel with the grade and stage of the disease. In the areas where fibrosis was seen, c‐kit positivity was rare or absent. In the HCC specimens, c‐kit positivity appeared both inside and around the cancerous nodes. C‐kit expression was observed in 62 of 75 HCC tissue specimens (82%) (p < 0.001). Conclusions: C‐kit positivity was observed in the mitotic, proliferating and also dysplastic hepatic cells. These results suggest that c‐kit expression may be used as an early diagnostic indicator for HBV induced HCC.     

Attenuation of the side effect profile of regadenoson: a randomized double-blind placebo-controlled study with aminophylline in patients undergoing myocardial perfusion imaging and have severe chronic kidney disease—the ASSUAGE-CKD trial

A subgroup analysis of the ASSUAGE trial suggested that the standardized intravenous aminophylline administration following regadenoson-stress leads to substantial attenuation of regadenoson adverse-effects in patients with severe chronic kidney disease (CKD). In a randomized, double-blinded, placebo-controlled clinical trial of patients with stage 4 and 5 CKD, we compared the frequency and severity of regadenoson adverse-effects in those who received 75 mg of intravenous aminophylline versus a matching placebo administered 90 s post-radioisotope injection. Consecutive 300 patients with severe CKD (36 % women; 86 % end-stage renal disease; age 55 (±13) years) were randomized to receive aminophylline (n = 150) or placebo (n = 150). In the aminophylline arm, there was 65 % reduction in the incidence of the primary endpoint of diarrhea (9 (6.0 %) vs. 26 (17.3 %), P = 0.002), 51 % reduction in the secondary endpoint of any regadenoson adverse-effect (47 (31.3 %) vs. 96 (64 %), P < 0.001) and 70 % reduction in headache (16 (10.7 %) vs. 54 (36 %), P < 0.001). The stress protocol was better tolerated in the aminophylline group (P = 0.008). The quantitative summed difference score, as a measure of stress-induced ischemic burden, was similar between the study groups (P = 0.51). In conclusion, the routine standardized administration of intravenous aminophylline in patients with severe CKD substantially reduces the frequency and severity of the adverse-effects associated with regadenoson-stress without changing the ischemic burden. [NCT01336140]     

Cellular Pharmacology of the Anti-Hepatitis B Virus Agent β-l-2′,3′-Didehydro-2′,3′-Dideoxy-N4-Hydroxycytidine: Relevance for Activation in HepG2 Cells

ß-l-2′,3′-Didehydro-2′,3′-dideoxy-N⁴-hydroxycytidine (l-Hyd4C) was demonstrated to be an effective and highly selective inhibitor of hepatitis B virus (HBV) replication in HepG2.2.15 cells (50% effective dose [ED₅₀] = 0.03 μM; 50% cytotoxic dose [CD₅₀] = 2,500 μM). In the present study, we investigated the intracellular pharmacology of tritiated l-Hyd4C in HepG2 cells. l-[³H]Hyd4C was shown to be phosphorylated extensively and rapidly to the 5′-mono-, 5′-di-, and 5′-triphosphate derivatives. Other metabolites deriving from a reduction or removal of the NHOH group of l-Hyd4C could not be detected, although both reactions were described as the primary catabolic pathways of the stereoisomer ß-d-N⁴-hydroxycytidine in HepG2 cells. Also, the formation of liponucleotide metabolites, such as the 5′-diphosphocholine derivative of l-Hyd4C, as described for some l-deoxycytidine analogues, seems to be unlikely. After incubation of HepG2 cells with 10 μM l-[³H]Hyd4C for 24 h, the 5′-triphosphate accumulated to 19.4 ± 2.7 pmol/10⁶ cells. The predominant peak belonged to 5-diphosphate, with 43.5 ± 4.3 pmol/10⁶ cells. The intracellular half-life of the 5′-triphosphate was estimated to be 29.7 h. This extended half-life probably reflects a generally low affinity of 5′-phosphorylated l-deoxycytidine derivatives for phosphate-degrading enzymes but may additionally be caused by an efficient rephosphorylation of the 5′-diphosphate during a drug-free incubation. The high 5′-triphosphate level and its extended half-life in HepG2 cells are consistent with the potent antiviral activity of l-Hyd4C.A large number of nucleoside analogues have been described as inhibitors of hepatitis B virus (HBV) and HIV replication. Recently l-nucleoside analogues in particular have gained increasing interest. They are characterized by an opposite configuration from that of the natural d-nucleoside analogues and represent one of the most attractive groups of antiretroviral compounds, including ß-l-2′,3′-dideoxy-3-thiacytidine (3TC) and its 5-fluoro derivative (FTC), ß-l-2′,3′-didehydro-2′,3′-dideoxy-cytidine (l-d4C) and its 5-fluoro derivative (l-d4FC), ß-l-thymidine, ß-l-fluoroarabinosylyluracil (l-FMAU), and ß-l-2′,3′-didehydro-2′,3′-dideoxy-2′-fluoro-cytidine (l-2′Fd4C) (3, 5, 22).Some of them not only have been found to be more potent than their corresponding d-nucleosides but seem to exhibit lower cytotoxicity and have been proved to be effective and selective agents for the treatment of chronic hepatitis B virus infections (4). However, only long-term therapy with a single nucleoside for several years was shown to be able to completely suppress HBV DNA in serum of patients and to reverse the progression of the disease. The disadvantage connected with such therapy regimens is the development of drug-resistant HBV strains (22). Therefore, the challenge will be to develop more-efficient drugs for shorter treatment regimens and to combine them to reach synergistic or at least additive drug action. This approach has been described not only as being highly efficient for the treatment of HIV infections but also as preventing the development of resistant mutants. Therefore, AIDS therapy is considered a model for future therapy of chronic HBV infections (17).Recently we described a series of new ß-l-N⁴-hydroxydeoxycytidine and ß-l-5-methyl-deoxycytidine derivatives as inhibitors of HBV replication. Between them, ß-l-2′,3′-didehydro-2′,3′-dideoxy-N⁴-hydroxycytidine (l-Hyd4C) (Fig. ​(Fig.1)1) emerged as the most effective in suppression of virus production in HepG2.2.15 cells (50% effective dose [ED₅₀] = 0.03 μM), displaying an extremely low cytotoxicity (50% cytotoxic dose [CD₅₀] for HepG2 cells = 2,500 μM) (12).Open in a separate windowFIG. 1.Structure of l-Hyd4C and possible metabolites formed by reduction (l-d4C) or by deamination (l-d4U).These encouraging features have prompted us to investigate the cellular pharmacology of l-Hyd4C in a hepatic cell line. This included the activation of this unnatural l-deoxycytidine nucleoside to its 5′-mono-, 5′-di-, and 5′-triphosphate, the search for other metabolites, and the estimation of the intracellular half-lives (t_1/2) of the 5′-di- and 5′-triphosphate of l-Hyd4C.(This work was presented in part at BIT''s 5th Anniversary Congress of International Drug Discovery Science and Technology, 7 to 13 November 2007, Xi''an and Beijing, China.)     

Does an enzyme other than thrombin contribute to unexpected changes in the levels of the different forms of thrombin activatable fibrinolysis inhibitor in patients with hemophilia A, hemophilia B and von Willebrand disease?

Pro-thrombin activatable fibrinolysis inhibitor (pro-TAFI), also called plasma procarboxypeptidase B or U, is one of the modulators of fibrinolysis in blood. Pro-TAFI is activated by thrombin/thrombomodulin complex or by plasmin to a carboxypeptidase B-like enzyme (TAFI) of 35.8 kD molecular weight. TAFI spontaneously becomes inactive as a result of a temperature-dependent conformational change in the protein (TAFIi). In this study, pro-TAFI, total TAFI antigen and TAFI-TAFIi antigen levels were measured in 32 patients with hemophilia A, 4 patients with hemophilia B, 21 patients with von Willebrand disease (VWD) and 13 healthy controls. A statistically significant decrease in pro-TAFI was found in all groups (10.72+/-4.57 mg/L (p<0.001); 8.00+/-2.35 mg/L (p<0.01) and 8.98+/-2.33 mg/L (p <0.001) for hemophilia A, hemophilia B and VWD, respectively) compared to controls (17.85+4.61 mg/L). A statistically significant increase in TAFI-TAFIi antigen was found in hemophilia A (1.05+/-1.01 mg/L) (p<0.05) and in VWD patients (0.96+/-1.01 mg/L) (p<0.05) compared to controls (0.55+/-0.36 mg/L). There was no difference in total TAFI antigen levels between any group of patients and the controls. Neither did pro-TAFI nor TAFI-TAFIi levels differ within the group of hemophilia A patients in relation to severity (mild, moderate and severe) or among the VWD patients in relation to subtype (type 1, type 2A and type 3). These findings indicate an increased conversion of pro-TAFI to TAFI and/or TAFIi in patients with bleeding disorders. As thrombin generation is seriously impaired in these patients and almost absent in hemophilia A and B and in type 3 VWD, it is possible that plasmin mediates pro-TAFI activation in these patients. Enhanced fibrinolysis via generation of plasmin has previously been reported in hemophilia and VWD. Activation of pro-TAFI by plasmin may be a feedback mechanism that counterbalances increased fibrinolysis in patients with bleeding disorders. The relationship between the TAFI activation pathway and bleeding complications associated with hemophilia A, hemophilia B and VWD requires further investigation.     

Evaluation of the dose—response relationship of aliskiren,a direct renin inhibitor,in an 8-week,multicenter, randomized,double-blind,parallel-group,placebo-controlled study in adult patients with stage 1 or 2 essential hypertension

Background: Aliskiren is approved for the treatment of hypertension at once-daily doses of 150 or 300 mg by the US Food and Drug Administration and the European Commission. It is generally well tolerated and provides 24-hour, dose-dependent blood pressure (BP) reduction; however, the effect of the 75-mg dose has been inconsistent in previous trials.Objectives: This study was designed to assess the efficacy and tolerability of once-daily administration of aliskiren 75 mg and to evaluate the dose-response relationship across all 3 doses of aliskiren (75, 150, and 300 mg).Methods: In this 8-week, multicenter, randomized, double-blind, parallel-group, placebo-controlled study, patients aged ≥18 years with stage 1 or 2 essential hypertension entered a 3- to 4-week, single-blind, placebo run-in period. Eligible patients were randomized (1:1:1:1) to receive oral, once-daily doses of aliskiren 75, 150, or 300 mg or placebo. The primary efficacy variable was the change from baseline in mean sitting diastolic BP (msDBP) at the week-8 end point. Tolerability was assessed by monitoring and recording all adverse events (AEs).Results: A total of 642 patients (mean [SD] age, 52.0 [10.73] years; 60.0% male; 80.8% white; mean body weight, 89.2 [18.4] kg [range, 50–160 kg]) were included in the study. Overall, 576 patients (89.7%) completed the double-blind treatment period. The most frequent reasons for discontinuation were unsatisfactory therapeutic effect (27/642 randomized patients [4.2%]) and AEs (17/642 [2.6%]). At end point, aliskiren 150 and 300 mg significantly reduced msDBP (both, P < 0.001) and mean sitting systolicConclusions: This study found a positive linear dose-response relationship in BP reduction with aliskiren 75, 150, and 300 mg dosed once daily, but only aliskiren 150 and 300 mg provided statistically significant reductions from baseline compared with placebo. All 3 doses of aliskiren were generally well tolerated.     

Inhibition of Human Hepatitis B Virus Replication by AT-61, a Phenylpropenamide Derivative,Alone and in Combination with (?)β-l-2′,3′-Dideoxy-3′-Thiacytidine

AT-61, a member of a novel class of phenylpropenamide derivatives, was found to be a highly selective and potent inhibitor of human hepatitis B virus (HBV) replication in four different human hepatoblastoma cell lines which support the replication of HBV (i.e., HepAD38, HepAD79, 2.2.15, and transiently transfected HepG2 cells). This compound was equally effective at inhibiting both the formation of intracellular immature core particles and the release of extracellular virions, with 50% effective concentrations ranging from 0.6 to 5.7 μM. AT-61 (27 μM) was able to reduce the amount of HBV covalently closed circular DNA found in the nuclei of HepAD38 cells by >99%. AT-61 at concentrations of >27 μM had little effect on the amount of viral RNA found within the cytoplasms of induced HepAD38 cells but reduced the number of immature virions which contained pregenomic RNA by >99%. The potency of AT-61 was not affected by one of the mutations responsible for (−)-β-l-2′,3′-dideoxy-3′ thiacytidine (3TC) resistance in HBV, and AT-61 acted synergistic with 3TC to inhibit HBV replication. AT-61 (81 μM) was not cytotoxic or antiproliferative to several cell lines and had no antiviral effect on woodchuck or duck HBV, human immunodeficiency virus type 1, herpes simplex virus type 1, vesicular stomatitis virus, or Newcastle disease virus. Therefore, we concluded that the antiviral activity of AT-61 is specific for HBV replication and most likely occurs at one of the steps between the synthesis of viral RNA and the packaging of pregenomic RNA into immature core particles.Hepatitis B virus (HBV) is estimated to chronically infect approximately 300 million people worldwide. These individuals are at increased risk for the development of liver failure, cirrhosis, and hepatocellular carcinoma (3, 23). In addition, it is estimated that of those chronically infected, approximately 1 million die annually from HBV-induced liver disease (19).At the present, interferon (IFN) is the only available treatment for chronic hepatitis in the United States. However, its efficacy is partial and of limited duration, with less than 30% of the chronic carriers being treated with IFN responding to treatment. In addition, approximately 50% of those who initially respond to IFN therapy experience a recurrence of viremia after the cessation of treatment (6, 29). In clinical trials, two nucleoside analogs, lamivudine [(−)-β-l-2′,3′-dideoxy-3′-thiacytidine; 3TC] and ganciclovir, have proven to be effective in decreasing the levels of HBV DNA in the serum of chronically infected patients (4, 7–9). However, many patients relapsed shortly after the cessation of therapy. In addition, there are now reports of the isolation of 3TC-resistant variants of HBV from the serum of immunosuppressed patients undergoing 3TC therapy (2, 20, 30).Here we report that AT-61, a member of a class of phenylpropenamide derivatives with antiviral activity against HBV replication (22), is a potent inhibitor of the replication of both wild-type and 3TC-resistant HBV in HepAD38, HepAD79, 2.2.15, and transiently transfected HepG2 cell lines. This compound does not inhibit the replication of duck HBV (DHBV), woodchuck HBV (WHBV), human immunodeficiency virus (HIV) type 1 (HIV-1), herpes simplex virus (HSV) type 1, (HSV-1), vesicular stomatitis virus (VSV), or Newcastle disease virus (NDV) and has very low toxicity in a number of cell lines. Moreover, when used in combination with 3TC, AT-61 acted synergistically to inhibit HBV replication in HepAD38 cells. Finally, the data suggest that this compound may exert its antiviral effect by interfering with the packaging of the pregenomic RNA into the immature core particle.     

Urine 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG), a specific marker of oxidative stress,using direct,isocratic LC–MS/MS: Method evaluation and application in study of biological variation in healthy adults

BackgroundUrine 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is a specific biomarker of oxidative stress. We evaluated a modified LC–MS/MS assay for urine 8-oxodG and determined biological variation in healthy adults.MethodUntreated urine was injected into an isocratic LC–MS/MS system (positive-ion MRM mode). Urine 8-oxodG in 51 healthy volunteers was measured; within- and between-day variations in 23 healthy volunteers were investigated.ResultsDose–response was linear to 452 nmol/l; limit of detection = 2.3 nmol/l; within-run and between-run CVs were < 3.0% and < 4.7%, respectively; recovery = 97%–101%; accuracy = 97.7–103.5%. Urine 8-oxodG (median, mean [SD]): 1.70, 1.70[0.60]nmol/mmol creatinine (n = 51). Men had higher (p = 0.027) concentrations than women matched for age and body mass index: mean [SD]: 1.90[1.60]; n = 26 vs. 1.50[0.55]; n = 25. Within- and between-day variations were wide but random. No significant differences were seen overall across time-points within 1 day or at the same time-point across 5 consecutive days.ConclusionsThe method has advantages of speed and relative simplicity as it does not require sample pre-treatment for 8-oxodG extraction, the use of internal standard or gradient LC elution and has high linearity, specificity, precision and recovery. Biological variation in urine 8-oxodG is wide, but no within- or between-day differences at the group concentration were seen in healthy adults.