RESUMO
Leishmania is a trypanosomatid parasite that causes skin lesions in its cutaneous form. Current therapies rely on old and expensive drugs, against which the parasites have acquired considerable resistance. Trypanosomatids are unable to synthesize purines relying on salvaging from the host, and nucleoside analogues have emerged as attractive antiparasitic drug candidates. 4-Methyl-7-ß-D-ribofuranosyl-7H-pyrrolo[2,3-d]pyrimidine (CL5564), an analogue of tubercidin in which the amine has been replaced by a methyl group, demonstrates activity against Trypanosoma cruzi and Leishmania infantum. Herein, we investigated its in vitro and in vivo activity against L. amazonensis. CL5564 was 6.5-fold (P = 0.0002) more potent than milteforan™ (ML) against intracellular forms in peritoneal mouse macrophages, and highly selective, while combination with ML gave an additive effect. These results stimulated us to study the activity of CL5564 in mouse model of cutaneous Leishmania infection. BALB/c female and male mice infected by L. amazonensis treated with CL5564 (10 mg kg−1, intralesional route for five days) presented a >93% reduction of paw lesion size likely ML given orally at 40 mg kg−1, while the combination (10 + 40 mg kg−1 of CL5564 and ML, respectively) caused >96% reduction. The qPCR confirmed the suppression of parasite load, but only the combination approach reached 66% of parasitological cure. These results support additional studies with nucleoside derivatives.
Assuntos
Modelos Animais de Doenças , Leishmania mexicana , Leishmaniose Cutânea , Camundongos Endogâmicos BALB C , Animais , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/parasitologia , Camundongos , Feminino , Masculino , Leishmania mexicana/efeitos dos fármacos , Tubercidina/farmacologia , Tubercidina/análogos & derivados , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Antiprotozoários/administração & dosagem , Macrófagos Peritoneais/parasitologia , Macrófagos Peritoneais/efeitos dos fármacos , Leishmania/efeitos dos fármacosRESUMO
Current therapies for chronic hepatitis B (CHB) include nucleos(t)ide analogues (NAs) and interferon (IFN), but their relative efficacy as monotherapy or in combination has not been examined systematically for HBsAg loss (functional cure). Hence, we systematically reviewed the evidence for HBsAg loss in CHB patients treated with IFN, NA or the combination. We searched PubMed, EMBASE and abstracts from EASL, Asia Pacific Association for study of the Liver and American Association for the Study of Liver Disease for randomized controlled trials of CHB patients, comparing NA, IFN or the combination. The Cochrane Risk of Bias tool v2.0 and GRADE method were used. Analyses were stratified by NA genetic barrier, cirrhosis, type of combination therapy, HBeAg, treatment naivety, IFN dosage/duration and outcome duration. Sensitivity analysis was performed for selected strata, and HBsAg loss was measured at the end-of-study (EOS), end-of-treatment (EOT) or end-of-follow-up (EOF). Effects were reported as risk differences (RD) with 95% confidence intervals (CI) using a random-effects model. Forty-five studies were included, all with low risk of bias. For HBsAg loss at EOS, when comparing combination vs IFN, RD = 1%, 95%CI-1%, 2%; combination vs NA, RD = 5%, 95%CI 3%,7%; IFN vs NA, RD = 3%, 95%CI 2%,5%. Subgroup analysis showed a significant effect of standard IFN dose vs nonstandard; IFN duration ≥48 weeks vs <48 weeks, and loss of efficacy >2 years of follow-up. Similar findings were seen in HBsAg seroconversion, but only three studies reported HBsAg seroreversion. In conclusion, IFN monotherapy/combination had a small but significant increase in HBsAg loss over NA, associated with standard dose of IFN and ≥48 weeks of therapy, although this effect faded over time.
Assuntos
Antivirais , Antígenos de Superfície da Hepatite B , Hepatite B Crônica , Antivirais/uso terapêutico , Ásia , DNA Viral , Antígenos E da Hepatite B , Vírus da Hepatite B , Hepatite B Crônica/tratamento farmacológico , Humanos , Resultado do TratamentoRESUMO
Nucleos(t)ide analogues (NAs) are the main drug category used in chronic hepatitis B (CHB) treatment. Despite the fact that NAs have a favourable safety profile, undesired adverse events (AEs) may occur during the treatment of CHB. Given the eminent number of patients currently receiving NAs, even a small risk of any of these toxicities can represent a major medical issue. The main objective of this review was to analyse information available on AEs associated with the use of NAs in published studies. We choose the following MesH terms for this systematic review: chronic hepatitis B, side effects and treatment. All articles published from 1 January 1990 up to 19 February 2018 in MEDLINE of PubMed, EMBASE, the Cochrane Library and LILACS databases were searched. A total of 120 articles were selected for analysis, comprising 6419 patients treated with lamivudine (LAM), 5947 with entecavir (ETV), 3566 with tenofovir disoproxil fumarate (TDF), 3096 with telbivudine (LdT), 1178 with adefovir dipivoxil (ADV) and 876 with tenofovir alafenamide (TAF). The most common AEs in all NAs assessed were abdominal pain/discomfort, nasopharyngitis/upper respiratory tract infections, fatigue, and headache. TAF displays the highest density of AEs per patient treated among NAs (1.14 AE/treated patient). In conclusion, treatment of CHB with NAs is safe, with a low incidence of AEs. Despite the general understanding TAF being safer than TDF, the number of patients treated with TAF still is too small in comparison to other NAs to consolidate an accurate safety profile. PROSPERO Registration No. CRD42018086471.
Assuntos
Antivirais/efeitos adversos , Hepatite B Crônica/tratamento farmacológico , Antivirais/administração & dosagem , Humanos , Nucleosídeos/administração & dosagem , Nucleosídeos/efeitos adversos , Nucleotídeos/administração & dosagem , Nucleotídeos/efeitos adversosRESUMO
INTRODUCTION AND OBJECTIVE: The aim of the present study was to investigate the significance of serum HBsAg levels in treatment cessation of nucleoside analogues (NAs) in patients with chronic hepatitis B (CHB) infection. METHODS: In 158 CHB patients with long-term NAs treatment, 74 patients were in HBeAg negative and had a HBsAg level <1500IU/mL, 36 of whom were informed and consented to cease NAs. HBsAg, HBV DNA and liver function were examined in the 1st, 3rd, 6th, 9th and 12th month after treatment cessation. RESULTS: The sustained response rate was 88.89% (32/36) within one year after NAs cessation. Sub-group analysis was based on HBsAg levels of patients with NAs cessation, there was no relapse case in 11 patients whose HBsAg <50IU/mL, and the negative predictive value (NPV) was 100%. Seroconversion of HBsAg occurred in 3 patients. 2 patients from 21 cases whose HBsAg was between 50IU/mL and 1000IU/mL relapsed. 2 of 4 patients whose in HBsAg >1000IU/mL relapsed. HBsAg of patients with a sustained response decreased slowly. In contrast, HBsAg levels increased gradually in relapsed patients, and the increase of HBsAg was precedent to relapses of HBV DNA and ALT. Multivariate analysis suggested that only HBsAg level showed a close correlation with HBV DNA relapses. ROC curve analysis suggested that the increase of HBsAg level in the 3rd and 6th month after NAs cessation had a great predictive value for relapses. CONCLUSION: Monitoring of base line HBsAg level can predict outcomes of NAs cessation in HBeAg-negative chronic hepatitis B. HBsAg <50IU/mL has higher predictive values of better sustained responses in HBeAg-negative CHB patients.
Assuntos
Antivirais/uso terapêutico , Antígenos de Superfície da Hepatite B/sangue , Hepatite B Crônica/tratamento farmacológico , Resposta Viral Sustentada , Adenina/análogos & derivados , Adenina/uso terapêutico , Idoso , Alanina Transaminase/sangue , DNA Viral , Desprescrições , Duração da Terapia , Feminino , Guanina/análogos & derivados , Guanina/uso terapêutico , Antígenos E da Hepatite B/sangue , Hepatite B Crônica/sangue , Humanos , Lamivudina/uso terapêutico , Masculino , Pessoa de Meia-Idade , Nucleosídeos , Organofosfonatos/uso terapêutico , Recidiva , Estudos Retrospectivos , Telbivudina/uso terapêuticoRESUMO
Here, we report a convenient synthetic procedure for the preparation of four novel indanyl carbanucleoside derivatives in the racemic form. The action of these compounds against hepatitis C virus was evaluated in vitro using the replicon cell line, Huh7.5 SG. Contrary to our expectations, all these compounds did not inhibit, but rather promoted HCV genotype 1b (HCVg1b) replication. Similar effects have been reported for morphine in the replicon cell lines, Huh7 and Huh8. Several biological experiments and computational studies were performed to elucidate the effect of these compounds on HCVg1b replication. Based on all the experiments performed, we propose that the increase in HCVg1b replication could be mediated, at least in part, by a similar mechanism to that of morphine on the enhancement of this replication. The presence of opioid receptors in Huh7.5 SG cells was indirectly determined for the first time in this work.
Assuntos
Antivirais/síntese química , Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Hepacivirus/fisiologia , Nucleosídeos/síntese química , Nucleosídeos/farmacologia , Replicação Viral/efeitos dos fármacos , Antivirais/química , Técnicas de Cultura de Células , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Química Sintética , Relação Dose-Resposta a Droga , Hepatite C/virologia , Humanos , Modelos Moleculares , Conformação Molecular , Estrutura Molecular , Nucleosídeos/análogos & derivadosRESUMO
The present study developed and characterized microparticles formulations containing acyclovir and curcumin co-encapsulated in order to overcome the biopharmaceutical limitations and increase the antiviral effect of both drugs. The microparticles were prepared by a spray drying methodology following the ratio 1:3 (drug:polymer), which were made by hydroxypropylmethylcellulose (HPMC) and/or Eudragit® RS100 (EUD). The MP-1 formulation was composed of HPMC and EUD (1:1), MP-2 formulation was composed only of HPMC and MP-3 formulation was composed only of EUD. All formulations showed yielding around 50% and acceptable powder flowability. Drug content determination around 82.1-96.8% and 81.8-87% for acyclovir and curcumin, respectively. The microparticles had spherical shape, size within 11.5-15.3⯵m, unimodal distribution and no chemical interactions among the components of the formulations. Of particular importance, the polymeric composition considerably influenced on the release profile of the drugs. The in vitro release experiment demonstrated that the microencapsulation provided a sustained release of acyclovir as well as increased the solubility of curcumin. Besides, mathematical modeling indicated that the experimental fit biexponential equation. Importantly, drugs microencapsulation promoted superior antiviral effect against BoVH-1 virus in comparison to their free form, which could be attributed to the improvement in the aforementioned physicochemical parameters. Therefore, these formulations could be promising technological drug carriers for acyclovir and curcumin, which highlight the great offering a potential alternative treatment for viral herpes.
Assuntos
Aciclovir , Antivirais , Curcumina , Portadores de Fármacos , Resinas Acrílicas/administração & dosagem , Resinas Acrílicas/química , Aciclovir/administração & dosagem , Aciclovir/química , Animais , Antivirais/administração & dosagem , Antivirais/química , Bovinos , Linhagem Celular , Curcumina/administração & dosagem , Curcumina/química , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/química , Composição de Medicamentos , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Herpesvirus Bovino 1/efeitos dos fármacos , Derivados da Hipromelose/administração & dosagem , Derivados da Hipromelose/químicaRESUMO
INTRODUCTION: Quantitative hepatitis B surface antigen (qHBsAg) combined with HBV DNA may be useful for predicting chronic hepatitis B (CHB) activity and nucleoside analogue (NA) response. MATERIAL AND METHODS: In this retrospective cohort study we evaluated qHBsAg levels according to CHB disease phase and among patients on treatment. Random effect logistic regression analysis was used to analyze qHBsAg change with time in the NA-treated cohort. RESULTS: 545 CHB carriers [56% M, median age 48 y (IQR 38-59), 73% Asian] had qHBsAg testing. In the untreated group (44%), 8% were classified as immune tolerant, 10% immune clearance, 40% inactive, and 43% had HBeAg- CHB and the median HBsAg levels were 4.6 (IQR 3.4-4.9), 4.0 (IQR 3.4-4.5), 2.9 (IQR 1.4-3.8), and 3.2 log IU/mL (IQR 2.6-4.0), respectively; p < 0.001. In the NA-treated group (28% entecavir, 68% tenofovir, 4% lamivudine), no significant change in qHBsAg levels occured with time. However, 19% of patients on long-term NA had sustained qHBsAg < 2 log10 IU/mL. CONCLUSION: qHBsAg titers were associated with CHB phase and remained stable in those on long-term NA. A significant number of treated patients had low-level qHBsAg, of which some may be eligible for treatment discontinuation without risk of flare.
Assuntos
Antivirais/uso terapêutico , Monitoramento de Medicamentos/métodos , Antígenos de Superfície da Hepatite B/sangue , Vírus da Hepatite B/efeitos dos fármacos , Hepatite B Crônica/tratamento farmacológico , Adulto , Biomarcadores/sangue , Canadá/epidemiologia , DNA Viral/genética , Feminino , Seguimentos , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Hepatite B Crônica/diagnóstico , Hepatite B Crônica/epidemiologia , Hepatite B Crônica/virologia , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento , Carga ViralRESUMO
Processes catalyzed by enzymes offer numerous advantages over chemical methods although in many occasions the stability of the biocatalysts becomes a serious concern. Traditionally, synthesis of nucleosides using poorly water-soluble purine bases, such as guanine, xanthine, or hypoxanthine, requires alkaline pH and/or high temperatures in order to solubilize the substrate. In this work, we demonstrate that the 2'-deoxyribosyltransferase from Leishmania mexicana (LmPDT) exhibits an unusually high activity and stability under alkaline conditions (pH 8-10) across a broad range of temperatures (30-70 °C) and ionic strengths (0-500 mM NaCl). Conversely, analysis of the crystal structure of LmPDT together with comparisons with hexameric, bacterial homologues revealed the importance of the relationships between the oligomeric state and the active site architecture within this family of enzymes. Moreover, molecular dynamics and docking approaches provided structural insights into the substrate-binding mode. Biochemical characterization of LmPDT identifies the enzyme as a type I NDT (PDT), exhibiting excellent activity, with specific activity values 100- and 4000-fold higher than the ones reported for other PDTs. Interestingly, LmPDT remained stable during 36 h at different pH values at 40 °C. In order to explore the potential of LmPDT as an industrial biocatalyst, enzymatic production of several natural and non-natural therapeutic nucleosides, such as vidarabine (ara A), didanosine (ddI), ddG, or 2'-fluoro-2'-deoxyguanosine, was carried out using poorly water-soluble purines. Noteworthy, this is the first time that the enzymatic synthesis of 2'-fluoro-2'-deoxyguanosine, ara G, and ara H by a 2'-deoxyribosyltransferase is reported.
Assuntos
Leishmania mexicana/enzimologia , Nucleosídeos/biossíntese , Pentosiltransferases/metabolismo , Purinas/química , Sequência de Aminoácidos , Biocatálise , Clonagem Molecular , Biologia Computacional , Enzimas Imobilizadas , Concentração de Íons de Hidrogênio , Leishmania mexicana/genética , Pentosiltransferases/genética , Conformação Proteica , Alinhamento de Sequência , Especificidade por Substrato , TemperaturaRESUMO
Nos últimos anos, houve um grande progresso no tratamento da hepatite B crônica. Cinco drogas são hoje aprovadas para tratamento dessa virose: intérferon alfa, lamivudina, adefovir, entecavir e telbivudina. Os intérferons (convencionais ou peguilados) foram as primeiras drogas utilizadas no tratamento dessas infecções podendo levar a resposta sustentada (perda do DNA-VHB e do AgHbe) em até um terço dos casos tratados. Um grande número de análogos de nucleosídeos/nucleotídeos estão no momento, disponíveis para tratar a hepatite B; a eficácia da lamivudina, o primeiro análogo de nucleosídeo utilizado, é limitada pela elevada incidência de resistência. O adefovir tem eficácia comparável à lamivudina porém baixa freqüência de resistência. Entecavir e tenofovir também se mostram muito ativos em controlar a replicação do vírus da hepatite B, e estão associados com mínimo desenvolvimento de resistência, mesmo em tratamento prolongados. Outras drogas, tais como telbivudina, emtricitabina e clevudine, se tornarão em futuro próximo, novas armas no controle dessa virose. Co-infectados HIV/VHB representam um grupo de doentes de difícil manuseio e que hoje se beneficiam com combinações de drogas no esquema anti-retroviral potente que devem atuar em ambas as viroses. O desenvolvimento de antivirais mais potentes e novas associações de medicamentos, conjuntamente com a melhor compreensão dos mecanismos de resistência do vírus da hepatite B a terapia são importantes conquistas para melhorar a eficácia do tratamento e diminuir no futuro, a carga global de portadores do vírus da hepatite B.
Over the last years there has been considerable progress in the treatment of chronic hepatitis B. Five drugs are now approved for the treatment of this virosis: interferon alpha, lamivudine, adefovir, entecavir and telbivudine. Interferons (conventional or PEG) were the first medicine used in the treatment of hepatitis being able to lead the persistent response (loss of DNA-HBV and of AgHbe) to up to one third of treated cases. A large number of nucleoside/nucleotide analogues are, at present, available to treat hepatitis B. The efficacy of lamivudine, the first nucleoside analogue used, is limited by the high rate of resistance. Adefovir has efficacy comparable to that of lamivudine, but with low resistance rate. Entecavir and tenofovir have also been particularly active in the control of hepatitis B virus replication and are associated with minimal resistance development, even during long treatment regimens. Other drugs, such as telbivudine, emtricitabine and clevudine, will become new treatment options in the near future. Individuals co-infected with HIV/HBV are particularly difficult to manage and are nowadays able to benefit from combinations of drugs of the HAART therapy, which should be effective towards both viruses. The development of more potent antiviral drugs as well as new drug combinations, together with a better understanding of hepatitis B virus resistance mechanisms are important milestones to improve treatment efficacy and to diminish, in the future, the global burden of hepatitis B virus.