Peroxisome Proliferator-Activated Receptor-α (PPARα) Expression in a Clinical Population of Pakistani Patients with Type 2 Diabetes and Dyslipidemia.

Poor glycemic control and dyslipidemia are hallmarks of type 2 diabetes mellitus (T2DM), which predispose to cardiovascular diseases. Peroxisome proliferator-activated receptor-α (PPARα) has been associated with atherosclerosis, but its role in T2DM is less clear. Previously, we studied PPARα expression levels in diabetics with and without dyslipidemia (DD). In this study we described the association with fasting blood glucose, HbA1c levels and lipid levels of the study population. Patient demography and biochemical data were collected from hospitals in Islamabad, Pakistan, and RT-PCR data of PPARα expression were retrieved from our previous study from the same cohort. We performed t-tests and regression analysis to evaluate the relationships between PPARα expression and demographic and clinical variables. As expected, body mass index and HbA1c were elevated in T2DM and DD patients compared to controls. Blood lipids (total cholesterol, triglycerides, LDL and HDL) were significantly higher in the DD group compared to the other two groups. In the T2DM and DD groups, the PPARα expression was not associated with any of the physical and biochemical parameters measured in this study. Expression of the PPARα gene was independent of blood lipids and glycemic control in this study. Further research is necessary to better understand the biological parameters of PPARα expression.

SB 9200, a novel agonist of innate immunity, shows potent antiviral activity against resistant HCV variants.

SB 9200 is a novel, first-in-class oral modulator of innate immunity that is believed to act via the activation of the RIG-I and NOD2 pathways. SB 9200 has broad-spectrum antiviral activity against RNA viruses including hepatitis C virus (HCV), norovirus, respiratory syncytial virus, and influenza and has demonstrated activity against hepatitis B virus (HBV) in vitro and in vivo. In phase I clinical trials in chronically infected HCV patients, SB 9200 has been shown to reduce HCV RNA by up to 1.9 log10 . Here, we demonstrate the antiviral activity of SB 9200 against a HCV replicon system and patient derived virus. Using the HCV capture-fusion assay, we show that SB 9200 is active against diverse HCV genotypes and is also effective against HCV derived from patients who relapse following direct-acting antiviral treatment, including viruses containing known NS5A resistance-associated sequences. These data confirm the broad antiviral activity of SB 9200 and indicate that it may have clinical utility in HCV patients who have failed to respond to current antiviral regimens.

Transcriptomic Analysis of Alzheimer's Disease Pathways in a Pakistani Population.

Background: Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder that is most prevalent in elderly individuals, especially in developed countries, and its prevalence is now increasing in developing countries like Pakistan. Objective: Our goal was to characterize key genes and their levels of expression and related molecular transcriptome networks associated with AD pathogenesis in a pilot case-control study in a Pakistani population. Methods: To obtain the spectrum of molecular networks associated with pathogenesis in AD patients in Pakistan (comparing cases and controls), we used high-throughput qRT-PCR (TaqMan Low-Density Array; n = 33 subjects) coupled with Affymetrix Arrays (n = 8) and Ingenuity Pathway Analysis (IPA) to identify signature genes associated with Amyloid processing and disease pathways. Results: We confirmed 16 differentially expressed AD-related genes, including maximum fold changes observed in CAPNS2 and CAPN1. The global gene expression study observed that 61% and 39% of genes were significantly (p-value 0.05) up- and downregulated, respectively, in AD patients compared to healthy controls. The key pathways include, e.g., Amyloid Processing, Neuroinflammation Signaling, and ErbB4 Signaling. The top-scoring networks in Diseases and Disorders Development were Neurological Disease, Organismal Injury and Abnormalities, and Psychological Disorders. Conclusions: Our pilot study offers a non-invasive and efficient way of investigating gene expression patterns by combining TLDA and global gene expression method in AD patients by utilizing whole blood. This provides valuable insights into the expression status of genes related to Amyloid Processing, which could play potential role in future studies to identify sensitive, early biomarkers of AD in general.

Reshaping an Acyclic Nucleoside Phosphonate into a Selective Anti-hepatitis B Virus Compound.

Minor structural modifications of acyclic nucleoside phosphonates can dramatically affect their antiviral properties. This work discloses a shift in the selectivity spectrum of 3-hydroxy-2-(phosphonomethoxy)propyl (HPMP) nucleotides from herpesviruses toward hepatitis B virus (HBV) induced by their acyclic chain 2-substitution with a nonpolar group. Two series of racemic (R,S)-2-methyl-3-hydroxy-2-(phosphonomethoxy)propyl (MHPMP) and (R,S)-2-ethynyl-3-hydroxy-2-(phosphonomethoxy)propyl (EHPMP) nucleotides were initially synthesized. Among these, guanine-containing derivatives exhibited significant anti-HBV activities in the submicromolar range. Enantioenriched MHPMPG and EHPMPG analogues were subsequently obtained by Sharpless asymmetric epoxidation. The (S)-enantiomers possessed an 8- to 26-fold higher potency than the relative (R)-forms. A further comparison of the EC90 values indicated that (S)-EHPMPG inhibited HBV replication more effectively than its 2-methyl analogue. A phosphonodiamidate prodrug of (S)-EHPMPG was thus prepared and found to exert a remarkably high anti-HBV activity (EC50 = 9.27 nM) with excellent selectivity (SI50 > 10,787), proving to be a promising candidate for anti-HBV drug development.

Orally bioavailable anti-HBV dinucleotide acyloxyalkyl prodrugs.

The acyloxyalkyl derivatives of a model anti-HBV dinucleotide were synthesized and evaluated as orally bioavailable prodrugs. Our studies have led to the identification of the first orally bioavailable dinucleotide prodrugs for further therapeutic development against the hepatitis B virus (HBV).

Small Animal Models for Human Immunodeficiency Virus (HIV), Hepatitis B, and Tuberculosis: Proceedings of an NIAID Workshop.

The main advantage of animal models of infectious diseases over in vitro studies is the gain in the understanding of the complex dynamics between the immune system and the pathogen. While small animal models have practical advantages over large animal models, it is crucial to be aware of their limitations. Although the small animal model at least needs to be susceptible to the pathogen under study to obtain meaningful data, key elements of pathogenesis should also be reflected when compared to humans. Well-designed small animal models for HIV, hepatitis viruses and tuberculosis require, additionally, a thorough understanding of the similarities and differences in the immune responses between humans and small animals and should incorporate that knowledge into the goals of the study. To discuss these considerations, the NIAID hosted a workshop on 'Small Animal Models for HIV, Hepatitis B, and Tuberculosis' on May 30, 2019. Highlights of the workshop are outlined below.

The octadecyloxyethyl ester of (S)-9-[3-hydroxy-2-(phosphonomethoxy) propyl]adenine is a potent and selective inhibitor of hepatitis C virus replication in genotype 1A, 1B, and 2A replicons.

The octadecyloxyethyl (ODE) and hexadecyloxypropyl (HDP) esters of (S)-9-[3-hydroxy-2-(phosphonomethoxy)propyl]adenine (HPMPA) are potent inhibitors of orthopoxvirus, herpesvirus, human immunodeficiency virus type 1, and hepatitis B virus replication in vitro. HDP and ODE esters of (S)-HPMPA and (R)-HPMPA were evaluated for their activity in hepatitis C virus (HCV) replicon assays using luciferase (1B and 2A replicons) or RNA (1B) quantification. The ODE ester of (S)-HPMPA [ODE-(S)-HPMPA] was the most active compound, with 50% effective concentrations (EC(50)s) in the 0.69 to 1.31 microM range. HDP and ODE esters of (R)-HPMPA were severalfold less active, while (S)-HPMPA and (R)-HPMPA were inactive. In genotype 1A and 1B replicons analyzed by HCV RNA analysis, ODE-(S)-HPMPA was the most active compound, with EC(50)s of 1.8 and 2.1 microM, respectively.

Alkoxyalkyl esters of 9-(s)-(3-hydroxy-2-phosphonomethoxypropyl) adenine are potent and selective inhibitors of hepatitis B virus (HBV) replication in vitro and in HBV transgenic mice in vivo.

Alkoxyalkyl esters of acyclic nucleoside phosphonates have previously been shown to have increased antiviral activity when they are administered orally in animal models of viral diseases, including lethal infections with vaccinia virus, cowpox virus, ectromelia virus, murine cytomegalovirus, and adenovirus. 9-(S)-(3-Hydroxy-2-phosphonomethoxypropyl)adenine [(S)-HPMPA] was previously shown to have activity against hepatitis B virus (HBV) in vitro. To assess the effect of alkoxyalkyl esterification of (S)-HPMPA, we prepared the hexadecyloxypropyl (HDP), 15-methyl-hexadecyloxypropyl (15M-HDP), and octadecyloxyethyl (ODE) esters and compared their activities with the activity of adefovir dipivoxil in vitro and in vivo. Alkoxyalkyl esters of (S)-HPMPA were 6 to 20 times more active than unmodified (S)-HPMPA on the basis of their 50% effective concentrations in 2.2.15 cells. The increased antiviral activity appeared to be due in part to the increased uptake and conversion of HDP-(S)-HPMPA to HPMPA diphosphate observed in HepG2 cells in vitro. HDP-(S)-HPMPA retained full activity against HBV mutants resistant to lamivudine (L180M, M204V), but cross-resistance to a mutant resistant to adefovir (N236T) was detected. HDP-(S)-HPMPA is orally bioavailable and provides excellent liver exposure to the drug. Oral treatment of HBV transgenic mice with HDP-(S)-HPMPA, 15M-HDP-(S)-HPMPA, and ODE-(S)-HPMPA for 14 days reduced liver HBV DNA levels by roughly 1.5 log units, a response equivalent to that of adefovir dipivoxil.

Potential for hepatitis C virus resistance to nitazoxanide or tizoxanide.

Nitazoxanide and its primary metabolite, tizoxanide, inhibit hepatitis C virus (HCV) replication in HCV replicon systems. To study the potential for resistance, we subjected Huh7 cells harboring HCV replicons to serial passage in 250 muM G418 and increasing concentrations of nitazoxanide or tizoxanide. Passage of the replicon-containing cell lines in either compound resulted in increases in the 50% effective concentrations (EC(50)s) (7- to 13-fold), EC(90)s (14- to 36-fold), and 50% cytotoxic concentrations (2- to 4-fold) of both compounds. Serial passage in either compound did not alter the susceptibility of HCV replicons to ribavirin or 2'-C-methylcytidine. Interestingly, serial passage in nitazoxanide or tizoxanide resulted in increased sensitivity to alpha interferon 2b: EC(50)s and EC(90)s were reduced three- and eightfold, respectively. Replicons isolated from these cell lines had no greater ability to confer tizoxanide resistance, or increased susceptibility to alpha interferon, than replicons isolated from the parental cell line that had not previously been exposed to nitazoxanide or tizoxanide. These findings are indicative of a cell-mediated activity differing from that of other anti-HCV drugs but complementary with interferon and are consistent with the enhanced response rates observed clinically when nitazoxanide is combined with pegylated interferon therapy. Finally, unlike data for other compounds in advanced clinical development for HCV, these data are consistent with resistance in HCV replicon-containing cell lines conferred by changes in the host and not by mutations in the virus.

Nitazoxanide, tizoxanide and other thiazolides are potent inhibitors of hepatitis B virus and hepatitis C virus replication.

Nitazoxanide (NTZ), a thiazolide anti-infective, is active against anaerobic bacteria, protozoa, and a range of viruses in cell culture models, and is currently in phase II clinical development for treating chronic hepatitis C. In this report, we characterize the activities of NTZ and its active metabolite, tizoxanide (TIZ), along with other thiazolides against hepatitis B virus (HBV) and hepatitis C virus (HCV) replication in standard antiviral assays. NTZ and TIZ exhibited potent inhibition of both HBV and HCV replication. NTZ was equally effective at inhibiting replication of lamivudine (LMV) and adefovir dipovoxil (ADV)-resistant HBV mutants and against 2'-C-methyl cytidine (2'CmeC) and telaprevir (VX-950)-resistant HCV mutants. NTZ displayed synergistic interactions with LMV or ADV against HBV, and with recombinant interferon alpha-2b (IFN) or 2'CmeC against HCV. Pre-treatment of HCV replicon-containing cells with NTZ potentiated the effect of subsequent treatment with NTZ plus IFN, but not NTZ plus 2'CmeC. NTZ induced reductions in several HBV proteins (HBsAg, HBeAg, HBcAg) produced by 2.2.15 cells, but did not affect HBV RNA transcription. NTZ, TIZ, and other thiazolides are promising new antiviral agents that may enhance current or future anti-hepatitis therapies.

Fluorinated methylenecyclopropane analogues of nucleosides. Synthesis and antiviral activity of (Z)- and (E)-9-{[(2-fluoromethyl-2-hydroxymethyl)-cyclopropylidene]methyl}adenine and -guanine.

Synthesis and antiviral activity of the title fluoromethylenecyclopropane analogues 15a, 15b, 16a, and 16b is described. Methylenecyclopropane carboxylate was first transformed to 2,2-bis-hydroxymethylmethylenecyclopropane. Selective monoacetylation followed by introduction of fluorine gave 2-acetoxymethyl-2-fluoromethylmethylenecyclopropane as the key intermediate. The synthesis of analogues 15a, 15b, 16a, and 16b then followed alkylation-elimination procedure as described previously for other methylenecyclopropane analogues [corrected] Compounds 15a, 15b, 16a and 16b were not active against Epstein-Barr virus (EBV) [corrected] Analogue 15a inhibited hepatitis C virus by virtue of its cytotoxicity and it moderately inhibited replication of the Towne strain of human cytomegalovirus (HCMV). The E-isomer 16a was a substrate for adenosine deaminase, whereas the Z-isomer 15a was not deaminated.

Nucleotide analogs as novel anti-hepatitis B virus agents.

During the past decade, nucleotide analogs have emerged as novel antiviral agents against hepatitis B virus. Adefovir dipivoxil, a prototype phosphonate analog, has been approved for chronic hepatitis B virus therapy, and additional phosphonate analogs and di- and tri-nucleotides are under development. Several innovative prodrug derivatizations have also been reported to improve the oral bioavailability of nucleotide analogs, which usually carry a negative charge.

Enhancement of antiviral activity against hepatitis C virus in vitro by interferon combination therapy.

Alpha, beta, and gamma interferons (IFN-alpha, IFN-beta, IFN-gamma) have been shown to be effective inhibitors of HCV replication in human cell lines carrying HCV replicons. To help define the divergent cellular processes involved in the control of intracellular HCV replication by these agents, we have characterized the activity of monotherapies and combination therapies with the major types of human interferons against HCV replication in the HCV replicon-containing cell line, AVA5. IFN-alpha, IFN-beta, and omega interferon (IFN-omega) were equally effective at inhibiting HCV replication, while IFN-gamma was approximately 10-fold more potent. In kinetic experiments, IFN-beta and IFN-gamma inhibited HCV replication more rapidly, and for a more prolonged period following the removal of treatment, than IFN-alpha. Combination interferon therapies produced enhanced anti-HCV activity in most cases, and displayed a diverse range of interactions. Mixtures of IFN-alpha and IFN-beta exhibited generally additive to slightly antagonistic interactions, IFN-alpha or IFN-beta combined with IFN-omega were strongly antagonistic, while IFN-alpha/IFN-gamma and IFN-beta/IFN-gamma combinations displayed the most enhanced and strongly synergistic antiviral effects. Simultaneous administration of interferons in the combination treatments was found to be superior to sequential administration. Ribavirin did not exhibit any selective anti-HCV activity in cell culture, consistent with in vivo monotherapies, and did not influence the effectiveness of IFN-alpha in combination treatments. A panel of human cytokines and immune response modifiers induced by interferon and ribavirin therapies in vivo did not demonstrate anti-HCV activity in HCV replicon-containing cultures. Combination therapy can be effectively modeled using HCV replicon technology yielding potentially more effective treatment regimens. HCV replicon technology has potential utility in designing combination therapies to significantly enhance the anti-HCV activity of IFN-alpha.

Clevudine therapy with vaccine inhibits progression of chronic hepatitis and delays onset of hepatocellular carcinoma in chronic woodchuck hepatitis virus infection.

We examined a rational approach to therapy of chronic hepatitis B virus (HBV) infection that utilized the reduction of viral load combined with appropriately timed immune modulation/stimulation. In a placebo-controlled study, chronic woodchuck hepatitis virus (WHV) carrier woodchucks received clevudine (L-FMAU), previously shown to have especially potent and sustained antiviral activity in woodchucks, for 32 weeks followed by WHV surface antigen (WHsAg) alum-adjuvanted vaccine at 32, 36, 40 and 48 weeks. Clevudine induced significant reductions in viraemia, surface antigenaemia, hepatic WHV nucleic acids, and hepatic core and surface antigens. Viral replication markers remained markedly suppressed in 75% of the clevudine-treated woodchucks following drug withdrawal, but remained at high levels in the vaccine monotherapy and placebo groups. Combination drug and vaccine therapy had benefits based on sustained reduction of viraemia, antigenaemia, and hepatic WHV DNA and RNA; inhibition of progression of chronic hepatitis; reduced frequency of chronic liver injury; and delayed onset of hepatocellular carcinoma (HCC). Combination therapy contributed to prevention of HCC in up to 38% of treated carriers, although the growth rate of established HCC was not affected. This study demonstrates enhanced benefits of combination chemo-immunotherapy against viral load and disease progression in chronic hepadnaviral infection, and provides a platform for further development of such treatment regimens.

Suppression of lamivudine-resistant B-domain mutants by adefovir dipivoxil in the woodchuck hepatitis virus model.

Adult woodchucks (Marmota monax) chronically infected with woodchuck hepatitis virus (WHV) were treated orally with lamivudine (15 mg/kg per day) for 57 weeks. After 20 weeks of treatment a 2-3 log reduction in serum WHV DNA was detected. Serum titers of WHV then increased gradually, in the presence of lamivudine treatment, reaching pre-treatment values by week 40. Viral recrudescence was associated with development of mutations in the B domain of the WHV polymerase gene. Mutations observed in the highly conserved FLLA motif of the B domain were L564V, L565M, and A566T, with A566T being the most frequently observed. Beginning on week 57 of lamivudine treatment, one group (n = 3) was treated orally with adefovir dipivoxil at a dose of 15 mg/kg per day plus lamivudine, and a second group (n = 3) was treated with H2O placebo plus lamivudine. In woodchucks treated with adefovir dipivoxil, two had the A566T mutation, and one had both A566T and L565V. In the group maintained on lamivudine monotherapy, A566T alone was present in one animal, another carried both A566T and L565V, and in the third, no B-domain mutations were detected. There was a 4.5 log reduction in serum WHV DNA after 12 weeks of treatment with the adefovir/lamivudine combination, while in the lamivudine monotherapy controls, WHV DNA decreased by only 0.83 log (P > 0.001). A slight recurrence in serum titers of WHV DNA was observed one week after withdrawal of adefovir treatment but no further increase in viral load was observed during the remainder of the 12-week post-treatment follow-up period. The results demonstrate that supplemental adefovir dipivoxil treatment is effective in suppressing replication of lamivudine-resistant B-domain mutants in the woodchuck model of hepatitis B virus infection.

Novel ring-expanded nucleoside analogs exhibit potent and selective inhibition of hepatitis B virus replication in cultured human hepatoblastoma cells.

Novel ring-expanded nucleoside (REN) analogs (1-3) containing 5:7 fused ring systems as the heterocyclic base were found to be potent and selective inhibitors of hepatitis B virus (HBV) replication in cultured human hepatoblastoma 2.2.15 cells. The most active compound, 6-amino-4,5-dihydro-8H-1-(beta-D-ribofuranosyl)imidazo[4,5-e][1,3]diazepine-4,8-dione (1), inhibited the synthesis of intracellular HBV replication intermediates and extracellular virion release in 2.2.15 cells with 50% effective concentration (EC50) of 0.604 and 0.131 microM, respectively. All three compounds had no effect on the synthesis of viral ribonucleic acids (RNA) in 2.2.15 cells. These compounds also exhibited low cellular toxicity in stationary and rapidly growing cell systems.

Mutations in the conserved woodchuck hepatitis virus polymerase FLLA and YMDD regions conferring resistance to lamivudine.

During more than 104 weeks of treatment with lamivudine (3TC) in chronic woodchuck hepatitis virus (WHV) carrier woodchucks, viral recrudescence occurred. Analysis of WHV DNA polymerase from woodchuck serum samples by PCR followed by DNA sequencing demonstrated that all samples were wild type at the conserved YMDD motif in domain C. Four of the six 3TC-treated woodchucks showed a mixture of the wild-type Ala (GCT) and the mutant Thr (ACT) at the conserved amino acid residue 566 (FLLA) in domain B of the WHV polymerase region. The appearance of the A566T mutation was temporally associated with viral recrudescence. This change is analogous with the amino acid 181 (FLLA) in HBV where 3TC selects for a change from Ala to Thr in humans. In the woodchuck, the Ala to Thr change in the polymerase gene results in a mutation of the WHV surface protein (amino acid 377) from Trp (TGG) to an opal codon (TGA), which may prematurely terminates the polypeptide. Three WHV molecular infectious clones were constructed to study this mutation in greater detail in vitro: A566T, analogous to A181T in HBV; M589V, analogous to the M204V in HBV; and the double mutant A566T/M589V, analogous to A181T/M204V in HBV. These mutants exhibited drug-sensitivity and replication profiles that paralleled those reported for analogous HBV variants. In transfected Huh7 cells, WHV containing the M589V mutation conferred at least 100-fold increased resistance to 3TC, but replicated approximately 5-fold less efficiently than wild-type virus as judged by both extracellular virus production and intracellular DNA replicative forms. In contrast, A566T mutant was approximately 10-fold more resistant to 3TC, replicated intracellularly as well as wild type, but produced 10-fold lower levels of virions than wild type. These findings are consistent with the observation that the A566T mutation alters the overlapping WHV surface antigen reading frame. WHV carrying mutations in the conserved YMDD motif, while not directly selected during lamivudine therapy in WHV carrier woodchucks, are replication competent in cell culture indicating the potential for their emergence in treated animals. These results further illustrate the utility of the WHV/woodchuck model to studies of HBV-drug resistance.

Viral pharmacodynamic model for (-)-beta-2',3'-dideoxy-5-fluoro-3'-thiacytidine (emtricitabine) in chronically infected woodchucks.

There is a need for adequate models of virus depletion in animals and humans as a function of drug dose in order to plan starting dose regimens in the clinic for new antiretroviral nucleoside agents. An indirect response pharmacodynamic model was fitted to link the plasma pharmacokinetics from a 28 day treatment with the nucleoside reverse transcription inhibitor emtricitabine [(-)-FTC], with the resulting virus depletion and recovery profiles in woodchucks chronically infected with woodchuck hepatitis B virus. In this approach it is assumed that the virus is eliminated from serum in a first order fashion and that the fraction of serum virus load produced per day is inhibited by the accumulation of nucleoside triphosphate in a manner that could be described using a Hill equation. Nadir virus load values were inversely related to pretreatment virus load levels within each dose group. A median inhibitory concentration value of 1.5 microM for (-)-FTC triphosphate, previously measured against the isolated viral polymerase of woodchuck hepatitis, was used in model fitting. The fitted value for concentration exponent eta of 3.46 indicated a greater than linear sensitivity of virus inhibition with dose. Since the post-treatment virus rebound was much greater than predictions of an initial model, a dose-dependent rebound factor was incorporated in the final model. The rebound factor was maximal at the end of (-)-FTC treatment and decayed mono-exponentially with a rate constant Kreb of 0.11/day. The model inferred decay half-life of (-)-FTC triphosphate in the apparent 'effect compartment' of the model was similar to the half-life value previously estimated for human hepatitis B virus-infected hepatocytes. The model described adequately the virus depletion and recovery profiles for the dose range tested and could be adapted for the selection of starting doses for future animal and human studies with emtricitabine and other nucleoside analogues in development.

Korean medicinal plant extracts exhibit antiviral potency against viral hepatitis.

OBJECTIVES: Investigation of natural ethnopharmacologic extracts exhibiting antiviral potential may lead to the discovery of new therapeutics for the treatment of chronic viral hepatitis infections. Traditional Korean medicinal herbs have been identified that exhibit potency against hepatitis B virus (HBV) and hepatitis C virus (HCV) infections. Research on the antiviral potential of naturally derived extracts is facilitated through the use of appropriate animal and liver cell culture models for these hepatotrophic pathogens. Objectives of this study were to demonstrate antiviral activity of an aqueous extract of herbal formulation KYH-1 in surrogate in vitro assays for HBV and HCV and identify mechanisms of action. METHODS: Antiviral potency of KYH-1 was measured in tissue culture systems that support replication of the woodchuck hepatitis virus (WHV), and the bovine viral diarrhea virus (BVDV). These assays serve as surrogate models for HBV and HCV, respectively. A recombinant HBV polymerase gene expression assay was used to define a molecular target. RESULTS: KYH-1 exhibited potent antiviral activity against WHV and to a lesser extent against BVDV. KYH-1 and its constituent components inhibited HBV polymerase priming in vitro. Additionally, KYH-1 suppressed HBV replication in a human hepatoblastoma cell line. CONCLUSION: Evaluation of naturally derived products for antiviral activity against HBV and HCV in standardized surrogate assays provides a scientific basis for potential use as complementary or alternative medicines. This study provides significant results justifying preclinical evaluation of KYH-1 as an antiviral therapy for HBV infections.

Treatment of norovirus infections: moving antivirals from the bench to the bedside.

Noroviruses (NV) are the most common cause of acute gastrointestinal illness in the United States and worldwide. The development of specific antiviral countermeasures has lagged behind that of other viral pathogens, primarily because norovirus disease has been perceived as brief and self-limiting and robust assays suitable for drug discovery have been lacking. The increasing recognition that NV illness can be life-threatening, especially in immunocompromised patients who often require prolonged hospitalization and intensive supportive care, has stimulated new research to develop an effective antiviral therapy. Here, we propose a path forward for evaluating drug therapy in norovirus-infected immunocompromised individuals, a population at high risk for serious and prolonged illness. The clinical and laboratory features of norovirus illness in immunocompromised patients are reviewed, and potential markers of drug efficacy are defined. We discuss the potential design of clinical trials in these patients and how an antiviral therapy that proves effective in immunocompromised patients might also be used in the setting of acute outbreaks, especially in confined settings such as nursing homes, to block the spread of infection and reduce the severity of illness. We conclude by reviewing the current status of approved and experimental compounds that might be evaluated in a hospital setting.