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BACKGROUND: Dolutegravir (DTG) is a novel yet preferential first- and -second-line treatment for persons living with HIV (PLH). Owing to its recent introduction, DTG-based regimens have not undergone a comprehensive, systematic evaluation regarding their real-world utilization and safety profile among a sizeable Indian population. OBJECTIVE: This study aimed to assess the 24 week immunovirological outcomes, anthropometric and metabolic changes, tolerability, and adverse events (AEs) of DTG-based antiretroviral (ART) regimens. METHODS: A single-centre phase-IV non-interventional observational study involving 322 ART naïve and treatment-experienced PLH initiating DTG-based-regimens until October 2022 were followed up for outcomes at 24 weeks. RESULTS: At 24 weeks, all PLH (n = 113) in the naïve group, all PLH (n = 67) in the first-line substitution group, 93.9% PLH (n = 46) in the first-line failure group, and 95.7% PLH (n = 89) in the second-line substitution group were virologically suppressed to plasma HIV-RNA <1000 copies/mL. Virological suppression rates to plasma HIV-RNA <200 copies/mL and <50 copies/mL were consistent among PLH who received DTG as first- or second-line ART. The mean-unadjusted weight gain observed was 3.5 kg (SE: 0.330), and it was significantly higher in PLH with poorer health at baseline (either HIV-RNA ≥ 1000 copies/ml or CD4 cell count <350 cells/µL). Overall, 27.3% PLH (n = 88) gained ≥10% of their baseline body weight, corresponding to 3.7% incidence (n = 12) of treatment-emergent clinical obesity. DTG had an overall lipid-neutral effect, with an advantageous effect being observed in PLH switching from non-nucleoside analogue reverse-transcriptase inhibitors (NNRTI) or ritonavir-boosted protease inhibitors (b/PI), especially in dyslipidemic pre-treated PLH (median change in total cholesterol: 28.5 mg/dL and triglycerides: 51 mg/dL), possibly emanating from the withdrawal of the offending ART. The incidence of DTG-specific AEs, including CNS AEs, was low. Two PLH developed proximal myopathy and one developed transaminitis, warranting DTG discontinuation. Asymptomatic serum-CPK elevation and drug-induced transaminitis were seen in 25.2% (n = 27) and 3.2% (n = 10) PLH, respectively. No apparent negative effects on renal function were detected. CONCLUSION: Our results from a large Indian cohort indicate a favourable virological and metabolic response, with good tolerance of DTG-based ART at 24 weeks.
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Infecciones por VIH , VIH-1 , Compuestos Heterocíclicos con 3 Anillos , Oxazinas , Piperazinas , Piridonas , Humanos , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/virología , Masculino , Adulto , Femenino , India/epidemiología , Compuestos Heterocíclicos con 3 Anillos/uso terapéutico , Compuestos Heterocíclicos con 3 Anillos/efectos adversos , Piridonas/uso terapéutico , VIH-1/efectos de los fármacos , Persona de Mediana Edad , Oxazinas/uso terapéutico , Piperazinas/uso terapéutico , Resultado del Tratamiento , Carga Viral/efectos de los fármacos , Fármacos Anti-VIH/uso terapéutico , Fármacos Anti-VIH/efectos adversos , Terapia Antirretroviral Altamente Activa/efectos adversos , Recuento de Linfocito CD4RESUMEN
Human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS), a lethal disease that is prevalent worldwide. According to the Joint United Nations Programme on HIV/AIDS (UNAIDS) data, 38.4 million people worldwide were living with HIV in 2021. Viral reverse transcriptase (RT) is an excellent target for drug intervention. Nucleoside reverse transcriptase inhibitors (NRTIs) were the first class of approved antiretroviral drugs. Later, a new type of non-nucleoside reverse transcriptase inhibitors (NNRTIs) were approved as anti-HIV drugs. Zidovudine, didanosine, and stavudine are FDA-approved NRTIs, while nevirapine, efavirenz, and delavirdine are FDA-approved NNRTIs. Several agents are in clinical trials, including apricitabine, racivir, elvucitabine, doravirine, dapivirine, and elsulfavirine. This review addresses HIV-1 structure, replication cycle, reverse transcription, and HIV drug targets. This study focuses on NRTIs and NNRTIs, their binding sites, mechanisms of action, FDA-approved drugs and drugs in clinical trials, their resistance and adverse effects, their molecular docking studies, and highly active antiretroviral therapy (HAART).
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Síndrome de Inmunodeficiencia Adquirida , Fármacos Anti-VIH , Infecciones por VIH , VIH-1 , Humanos , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/uso terapéutico , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Simulación del Acoplamiento Molecular , Infecciones por VIH/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida/inducido químicamente , Síndrome de Inmunodeficiencia Adquirida/tratamiento farmacológico , Transcriptasa Inversa del VIH/metabolismoRESUMEN
The identification and characterization of plasma proteins in drug resistant and drug sensitive in HIV-1 infected/AIDS patients were carried out using the SWATH-MS protocol. In total, 204 proteins were identified and quantified, 57 proteins were differentially expressed, out of which 25 proteins were down regulated and 32 proteins were up regulated in drug resistant patients. Six proteins such as complement C4-A, immunoglobulin heavy variable 1-2, carboxylic ester hydrolase, fibulin-1, immunoglobulin lambda constant7, secreted phosphoprotein 24 were differentially expressed in individuals with drug resistant HIV as compared to individuals with drug sensitive HIV. Gene ontology of 57 differentially expressed proteins was analysed and documented.
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Nucleoside reverse transcriptase inhibitors are the first class of drugs to be approved by the FDA for the suppression of HIV-1 and are widely used for this purpose in combination with drugs of other classes. Despite the progress in HIV-1 treatment, there is still the need to develop novel efficient antivirals. Here the efficiency of HIV-1 inhibition by a set of original 5-substituted uridine nucleosides was studied. We used the replication deficient human immunodeficiency virus (HIV-1)-based lentiviral particles and identified that among the studied compounds, 2',3'-isopropylidene-5-iodouridine was shown to cause anti-HIV-1 activity. Importantly, no toxic action of this compound against the cells of T-cell origin was found. We determined that this compound is significantly more efficient at suppressing HIV-1 compared to Azidothymidine (AZT) when taken at the high non-toxic concentrations. We did not find any profit when using AZT in combination with 2',3'-isopropylidene-5-iodouridine. 2',3'-Isopropylidene-5-iodouridine acts synergistically to repress HIV-1 when combined with the CDK4/6 inhibitor Palbociclib in low non-toxic concentration. No synergistic antiviral action was detected when AZT was combined with Palbociclib. We suggest 2',3'-isopropylidene-5-iodouridine as a novel perspective non-toxic compound that may be used for HIV-l suppression.
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The aim of this study was to investigate whether the use of nucleoside reverse transcriptase inhibitors (NRTIs) impacts the incidence of prediabetes or type 2 diabetes mellitus (T2DM) or the progression from prediabetes to T2DM in people living with HIV (PLWH). We conducted a retrospective cohort study using the U.S. Veterans Health Administration database among adult patients with an HIV diagnosis from the year 2000 until 2021 to determine the incidence of prediabetes and further progression to T2DM among NRTI exposed and unexposed patients. A multistate model was used to evaluate progression from normoglycemia to prediabetes and then to T2DM, and covariate adjustment with the Cox proportional hazards model was used to estimate the hazard ratios. Among 32,240 veterans diagnosed with HIV, prediabetes and T2DM were observed among 20.2% and 20.7% of patients, respectively. Among those diagnosed with prediabetes, 31.8% progressed to T2DM. Patients exposed to NRTIs at any time (86.6%), had a reduced risk of prediabetes [HR 0.50 (0.47-0.53 95% CI)] and among prediabetics, a lower risk of progression to T2DM [HR 0.73 (0.63-0.85 95% CI)] when compared to patients who never used NRTIs. In summary, NRTIs may reduce the risk of developing prediabetes and the progression from prediabetes to T2DM in PLWH.
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Hepatitis B virus (HBV) antiviral Resistance-Associated Mutations (RAMs) in human immunodeficiency virus (HIV) coinfected patients undergoing highly active antiretroviral therapy (HAART) are complex and incompletely understood. We aimed to determine the prevalence of HBV coinfection, HBV genotypes, and RAMs in a cohort of people living with HIV (PLWH) in the northeastern region of Colombia. This cross-sectional study was carried out between February 2013 and February 2014. Virological, immunological and HAART data were collected from clinical records. In-house nested PCR and Sanger sequencing of the HBV pol gene were used to identify coinfections, genotypes, RAMs and HBV s antigen (HBsAg) escape mutants. Among 275 PLWH, HBV coinfection was confirmed in 32 patients (11.6%), of whom nine (28.2%) were HBsAg positive (active hepatitis B), and 23 (71.8%) were occult hepatitis B infections (OBI). All HBV sequences (n = 23) belonged to the genotype F3. Among HIV/HBV coinfections, 71.9% had CD4+ T cell counts above 200 cells/mm3 and 37.5% had undetectable HIV viral loads. The RAMs rtL80I, rtL180M, and rtM204V, which confer resistance to Lamivudine/Telbivudine and partially resistant to Entecavir, were found in all HBV isolates. An unknown rt236Y mutation to Tenofovir was also identified. Most patients under HAART received first-generation HBV antiviral therapy with a low genetic barrier to resistance. Antiviral Drug-associated Potential Vaccine-escape Mutations (ADAPVEMs) in the S gene were observed in all isolates ranging from 1-20 amino acid substitutions. However, no vaccine escape mutants were detected. In Conclusion, these findings highlight the importance of HBV molecular screening, antiviral resistance monitoring and new guidelines for PLWH to overcome RAMs and prevent HBV-related liver disease.
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Human Immunodeficiency Virus (HIV) is one of the most common chronic infectious diseases in humans. Extending the expected lifetime of patients depends on the use of optimal antiretroviral therapies. Emergence of the drug-resistant strains can reduce the effectiveness of treatments and lead to Acquired Immunodeficiency Syndrome (AIDS), even with antiretroviral therapy. Investigating the genotype-phenotype relationship is a crucial process for optimizing the therapy protocols of the patients. Here, a mathematical modelling framework is proposed to address the impact of existing mutations, timing of initiation, and adherence levels of nucleotide reverse transcriptase inhibitors (NRTIs) on the evolutionary dynamics of the virus strains. For the first time, the existing Stanford HIV drug resistance data have been combined with a multi-strain within-host ordinary differential equation (ODE) model to track the dynamics of the most common NRTI-resistant strains. Overall, the D4T-3TC, D4T-AZT and TDF-D4T drug combinations have been shown to provide higher success rates in preventing treatment failure and further drug resistance. The results are in line with the genotype-phenotype data and pharmacokinetic parameters of the NRTI inhibitors. Moreover, we show that the undetectable mutant strains at the diagnosis have a significant effect on the success/failure rates of the NRTI treatments. Predictions on undetectable strains through our multi-strain within-host model yielded the possible role of viral evolution on the treatment outcomes. It has been recognized that the improvement of multi-scale models can contribute to the understanding of the evolutionary dynamics, and treatment options, and potentially increase the reliability of genotype-phenotype models.
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Fármacos Anti-VIH , Infecciones por VIH , VIH-1 , Humanos , Fármacos Anti-VIH/farmacología , Estavudina , Reproducibilidad de los Resultados , Infecciones por VIH/tratamiento farmacológicoRESUMEN
The manipulation of mitochondrial DNA (mtDNA) copy number in cultured cells, using substances that interfere with DNA replication, is a useful tool to investigate various aspects of mtDNA maintenance. Here we describe the use of 2',3'-dideoxycytidine (ddC) to induce a reversible reduction of mtDNA copy number in human primary fibroblasts and human embryonic kidney (HEK293) cells. Once the application of ddC is stopped, cells depleted for mtDNA attempt to recover normal mtDNA copy numbers. The dynamics of repopulation of mtDNA provide a valuable measure for the enzymatic activity of the mtDNA replication machinery.
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ADN Mitocondrial , Zalcitabina , Humanos , Zalcitabina/farmacología , ADN Mitocondrial/genética , Células HEK293 , Mitocondrias/genética , Células Cultivadas , Replicación del ADNRESUMEN
Background: Protease inhibitors (PIs) have been recommended as World Health Organization second-line antiretroviral therapy (ART) for low- to middle-income countries for two decades. As dolutegravir-based regimens have become widely available, the future role of PIs is uncertain. Objectives: To describe the characteristics of patients on PI-based ART (in first-line and second-line regimens), double-boosted protease inhibitors (DBPI) and patients who received recycled nucleoside reverse transcriptase inhibitors (NRTI) in second-line regimens at a tertiary level ART clinic. Method: We conducted a descriptive retrospective record review of adult patients on PI-based ART who attended Nthabiseng Adult Infectious Diseases Clinic at Chris Hani Baragwanath Academic Hospital in Soweto, South Africa, between January 2021 and April 2022. Results: Of the 900 patients sampled, 543 (60.3%) were female, the median age was 45 and 703 (79.1%) had viral loads (VL) below 1000 copies/mL. In contrast, 21 (58.3%) of 36 vertically infected patients had VLs below 1000 copies/mL. Thirty-seven (4.1%) patients were on DBPIs. The commonest reason for DBPI use in 24 (64.9%) patients was drug resistance test (DRT)-guided switch after virological failure. Forty-nine (5.4%) patients were on recycled NRTIs with no DRT, and 24 (2.6%) patients were on NRTIs to which there was documented resistance. Outcomes for these patients were similar to the total sample. Conclusion: PIs have long been a cornerstone of second-line ART. This study demonstrates the real-world utility of PIs, as well as their disadvantages. There was no difference in the outcomes of patients who received recycled NRTIs in second-line regimens.
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HIV reverse transcriptase (RT) inhibitors are the important components of highly active antiretroviral therapies (HAARTs) for anti-HIV treatment and pre-exposure prophylaxis in clinical practice. Many RT inhibitors and their combination regimens have been approved in the past ten years, but a review on their drug discovery, pharmacology, and clinical efficacy is lacking. Here, we provide a comprehensive review of RT inhibitors (tenofovir alafenamide, rilpivirine, doravirine, dapivirine, azvudine and elsulfavirine) approved in the past decade, regarding their drug discovery, pharmacology, and clinical efficacy in randomized controlled trials. Novel RT inhibitors such as islatravir, MK-8504, MK-8507, MK8583, IQP-0528, and MIV-150 will be also highlighted. Future development may focus on the new generation of novel antiretroviral inhibitors with higher bioavailability, longer elimination half-life, more favorable side-effect profiles, fewer drug-drug interactions, and higher activities against circulating drug-resistant strains.
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The urgent response to the COVID-19 pandemic required accelerated evaluation of many approved drugs as potential antiviral agents against the causative pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Using cell-based, biochemical, and modeling approaches, we studied the approved HIV-1 nucleoside/tide reverse transcriptase inhibitors (NRTIs) tenofovir (TFV) and emtricitabine (FTC), as well as prodrugs tenofovir alafenamide (TAF) and tenofovir disoproxilfumarate (TDF) for their antiviral effect against SARS-CoV-2. A comprehensive set of in vitro data indicates that TFV, TAF, TDF, and FTC are inactive against SARS-CoV-2. None of the NRTIs showed antiviral activity in SARS-CoV-2 infected A549-hACE2 cells or in primary normal human lung bronchial epithelial (NHBE) cells at concentrations up to 50 µM TAF, TDF, FTC, or 500 µM TFV. These results are corroborated by the low incorporation efficiency of respective NTP analogs by the SARS-CoV-2 RNA-dependent-RNA polymerase (RdRp), and lack of the RdRp inhibition. Structural modeling further demonstrated poor fitting of these NRTI active metabolites at the SARS-CoV-2 RdRp active site. Our data indicate that the HIV-1 NRTIs are unlikely direct-antivirals against SARS-CoV-2, and clinicians and researchers should exercise caution when exploring ideas of using these and other NRTIs to treat or prevent COVID-19.
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Fármacos Anti-VIH , Tratamiento Farmacológico de COVID-19 , Infecciones por VIH , VIH-1 , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Emtricitabina/farmacología , Emtricitabina/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Humanos , Nucleósidos/farmacología , Nucleósidos/uso terapéutico , Nucleótidos/farmacología , Pandemias , ARN Viral , ARN Polimerasa Dependiente del ARN , SARS-CoV-2 , Tenofovir/farmacología , Tenofovir/uso terapéuticoRESUMEN
HIV pre-exposure prophylaxis (HIV-PrEP) is effective in reducing the likelihood of HIV acquisition in HIV-negative people at high risk of exposure. Guidelines recommend testing for sexually transmitted infections (STIs) before starting, and periodically on PrEP, including bacterial infections, HIV, hepatitis C virus, and, for those who are non-immune, hepatitis B virus. Diagnosed infections can be promptly treated to reduce onward transmission. HTLV-1 is not mentioned; however, it is predominantly sexually transmitted, causes adult T-cell leukaemia/lymphoma (ATL) or myelopathy in 10% of those infected, and is associated with an increased risk of death in those without any classically HTLV-associated condition. The 2021 WHO Technical Report on HTLV-1 called for the strengthening of global public health measures against its spread. In this scoping review, we, therefore, (1) discuss the epidemiological context of HIV-PrEP and HTLV-1 transmission; (2) present current knowledge of antiretrovirals in relation to HTLV-1 transmission prevention, including nucleos(t)ide reverse transcriptase inhibitors (NRTIs) and integrase strand transfer inhibitors (INSTIs); and (3) identify knowledge gaps where data are urgently required to inform global public health measures to protect HIV-PrEP users from HTLV-1 acquisition. We suggest that systematic seroprevalence studies among PrEP-using groups, including men who have sex with men (MSM), people who inject drugs (PWIDs), and female sex workers (FSWs), are needed. Further data are required to evaluate antiretroviral efficacy in preventing HTLV-1 transmission from in vitro studies, animal models, and clinical cohorts. PrEP delivery programmes should consider prioritizing the long-acting injectable INSTI, cabotegravir, in HTLV-1 endemic settings.
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The enzyme reverse transcriptase (RT) plays a central role in the life cycle of human immunodeficiency virus (HIV), and RT has been an important drug target. Elucidations of the RT structures trapping and detailing the enzyme at various functional and conformational states by X-ray crystallography have been instrumental for understanding RT activities, inhibition, and drug resistance. The structures have contributed to anti-HIV drug development. Currently, two classes of RT inhibitors are in clinical use. These are nucleoside/nucleotide reverse transcriptase inhibitors (NRTIs) and non-nucleoside reverse transcriptase inhibitors (NNRTIs). However, the error-prone viral replication generates variants that frequently develop resistance to the available drugs, thus warranting a continued effort to seek more effective treatment options. RT also provides multiple additional potential druggable sites. Recently, the use of single-particle cryogenic electron microscopy (cryo-EM) enabled obtaining structures of NNRTI-inhibited HIV-1 RT/dsRNA initiation and RT/dsDNA elongation complexes that were unsuccessful by X-ray crystallography. The cryo-EM platform for the structural study of RT has been established to aid drug design. In this article, we review the roles of structural biology in understanding and targeting HIV RT in the past three decades and the recent structural insights of RT, using cryo-EM.
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Farmacorresistencia Viral , Infecciones por VIH , VIH-1 , Inhibidores de la Transcriptasa Inversa , Transcriptasa Inversa del VIH/genética , VIH-1/efectos de los fármacos , Humanos , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/uso terapéuticoRESUMEN
BACKGROUND & AIMS: HBV nucleos(t)ide reverse transcriptase inhibitors (NrtIs) do not completely suppress HBV replication. Previous reports indicate persistent viremia during NrtI treatment despite HBV DNA being undetectable. HBV core inhibitors may enhance viral suppression when combined with NrtIs. This phase II trial (NCT03576066) evaluated the efficacy and safety of the investigational core inhibitor, vebicorvir (VBR), in virologically- suppressed patients on NrtIs. METHODS: Non-cirrhotic, NrtI-suppressed patients with chronic HBV were randomised to VBR 300 mg once daily or matching placebo (PBO) for 24 weeks. Treatment was stratified by hepatitis B e antigen (HBeAg) status. The primary endpoint was change from Baseline in serum HBeAg or hepatitis B surface antigen (HBsAg) after 24 weeks. RESULTS: Of 73 patients enrolled, 47 were HBeAgâpositive and 26 were HBeAg negative. In HBeAg-positive and -negative patients, there were no differences in the change from Baseline at Week 24 for HBsAg or HBeAg. Using a novel, high-sensitivity assay to detect HBV DNA, a greater proportion of patients with detectable HBV DNA at Baseline achieved undetectable HBV DNA at Week 24 in the VBR+NrtI vs. PBO+NrtI group. In HBeAg-positive patients, a greater change from Baseline in HBV pregenomic (pg)RNA was observed at Week 24 with VBR+NrtI vs. PBO+NrtI. Treatment-emergent adverse events (TEAEs) in VBR+NrtI patients included upper respiratory tract infection, nausea, and pruritus. No serious adverse events, Grade 4 TEAEs, or deaths were reported. CONCLUSIONS: In this 24-week study, VBR+NrtI demonstrated a favourable safety and tolerability profile. While there were no significant changes in viral antigen levels, enhanced viral suppression was demonstrated by greater changes in DNA and pgRNA with the addition of VBR compared to NrtI alone. CLINICAL TRIALS NUMBER: NCT03576066. LAY SUMMARY: Core inhibitors represent a novel approach for the treatment of chronic hepatitis B virus (HBV) infection, with mechanisms of action distinct from existing treatments. In this study, vebicorvir added to existing therapy reduced HBV replication to a greater extent than existing treatment and was generally safe and well tolerated.
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Hepatitis B Crónica , Antivirales/efectos adversos , ADN Viral , Antígenos de Superficie de la Hepatitis B , Antígenos e de la Hepatitis B , Virus de la Hepatitis B/genética , HumanosRESUMEN
BACKGROUND: We report a case of sudden, lethal metabolic acidosis in a 70-year-old man on long-term nucleoside reverse transcriptase inhibitor (NRTI) -based antiretroviral therapy (ART) who had developed atypical necrotizing fasciitis 1 month after kidney transplantation. CASE PRESENTATION: The HIV infection of the patient was treated for the last four months with an integrase strand inhibitor (dolutegravir 50 mg/d) plus a NRTI backbone including lamivudine (150 mg/d) and abacavir (600 mg/d). In this renal transplant patient we hypothesize that the co-existence of sepsis, renal failure and an accumulation of lamivudine led to the development of fatal metabolic acidosis and hyperlactatemia. Although lamivudine is only rarely associated with hyperlactatemia, there is evidence that overdose may be a risk factor for developing it. In our patient the lamivudine concentration two days after stopping and during hemodiafiltration was more than 50 times higher than therapeutic target trough concentrations. Likely reasons for this were renal impairment and concurrent treatment with trimethoprim, known to inhibit the renal elimination of lamivudine. CONCLUSIONS: NRTIs could trigger the development of hyperlactatemia in septic patients. The use of NRTI sparing regimens might be considered in the presence of this critical condition.
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Acidosis Láctica , Fármacos Anti-VIH , Infecciones por VIH , Hiperlactatemia , Trasplante de Riñón , Lamivudine , Sepsis , Acidosis Láctica/inducido químicamente , Anciano , Fármacos Anti-VIH/efectos adversos , Infecciones por VIH/complicaciones , Infecciones por VIH/tratamiento farmacológico , Humanos , Hiperlactatemia/inducido químicamente , Trasplante de Riñón/efectos adversos , Lamivudine/efectos adversos , Masculino , Sepsis/tratamiento farmacológicoRESUMEN
Viral polymerase is an essential enzyme for the amplification of the viral genome and is one of the major targets of antiviral therapies. However, a serious concern to be solved in hepatitis B virus (HBV) infection is the difficulty of eliminating covalently closed circular (ccc) DNA. More recently, therapeutic strategies targeting various stages of the HBV lifecycle have been attempted. Although cccDNA-targeted therapies are attractive, there are still many problems to be overcome, and the development of novel polymerase inhibitors remains an important issue. Interferons and nucleos(t)ide reverse transcriptase inhibitors (NRTIs) are the only therapeutic options currently available for HBV infection. Many studies have reported that the combination of interferons and NRTI causes the loss of hepatitis B surface antigen (HBsAg), which is suggestive of seroconversion. Although NRTIs do not directly target cccDNA, they can strongly reduce the serum viral DNA load and could suppress the recycling step of cccDNA formation, improve liver fibrosis/cirrhosis, and reduce the risk of hepatocellular carcinoma. Here, we review recent studies on combination therapies using polymerase inhibitors and discuss the future directions of therapeutic strategies for HBV infection.
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Antivirales/uso terapéutico , ADN Polimerasa Dirigida por ADN/metabolismo , Quimioterapia Combinada/métodos , Virus de la Hepatitis B/efectos de los fármacos , Hepatitis B Crónica/tratamiento farmacológico , Inhibidores de la Síntesis del Ácido Nucleico/uso terapéutico , Ensayos Clínicos como Asunto , Virus de la Hepatitis B/enzimología , HumanosRESUMEN
The combination of the two nucleoside reverse transcriptase inhibitors (NRTI) tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is used in most highly active antiretroviral therapies for treatment of HIV-1 infection, as well as in pre-exposure prophylaxis against HIV acquisition. Administered as prodrugs, these drugs are taken up by HIV-infected target cells, undergo intracellular phosphorylation and compete with natural deoxynucleoside triphosphates (dNTP) for incorporation into nascent viral DNA during reverse transcription. Once incorporated, they halt reverse transcription. In vitro studies have proposed that TDF and FTC act synergistically within an HIV-infected cell. However, it is unclear whether, and which, direct drug-drug interactions mediate the apparent synergy. The goal of this work was to refine a mechanistic model for the molecular mechanism of action (MMOA) of nucleoside analogues in order to analyse whether putative direct interactions may account for the in vitro observed synergistic effects. Our analysis suggests that depletion of dNTP pools can explain apparent synergy between TDF and FTC in HIV-infected cells at clinically relevant concentrations. Dead-end complex (DEC) formation does not seem to significantly contribute to the synergistic effect. However, in the presence of non-nucleoside reverse transcriptase inhibitors (NNRTIs), its role might be more relevant, as previously reported in experimental in vitro studies.
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Emtricitabina/uso terapéutico , VIH-1/efectos de los fármacos , Tenofovir/uso terapéutico , Fármacos Anti-VIH/farmacología , Terapia Antirretroviral Altamente Activa/métodos , Desoxicitidina/análogos & derivados , Quimioterapia Combinada/métodos , Infecciones por VIH/tratamiento farmacológico , Transcriptasa Inversa del VIH/genética , VIH-1/patogenicidad , Humanos , Modelos Teóricos , Profilaxis Pre-Exposición/métodos , Transcripción Reversa/efectos de los fármacos , Tenofovir/metabolismoRESUMEN
There are about 2.1 million children infected with HIV globally and about 120,000 deaths annually. Nigeria has one of the highest rates of pediatric HIV infection globally. Pretreatment HIV drug resistance data inform the choice of first- and second-line antiretroviral therapy (ART) regimens. This study investigated the prevalence of HIV drug-resistant strains among ART-naive children in Ibadan, Nigeria. A total of 20 children aged <15 years were enrolled. Demographic, clinical, and laboratory data were documented. Total nucleic acid was extracted from blood samples after which amplification of HIV-1 pol gene was done using polymerase chain reaction. Amplified gene was sequenced using big dye sequencing method. The sequenced HIV-1 pol gene was typed and analyzed for identification of mutations indicative of drug resistance across the different classes of ART. HIV-1 RNA pol gene was successfully amplified in 12/20 (60%) children. All were identified as HIV-1 and the subtypes were G and CRF 02AG, recombinant of 02_AG/G and recombinant of 02_AG/A1. Drug-resistant mutations (DRMs) were identified in 4/12 (33%). Three out of the four mutations were identified as non-nucleoside reverse transcriptase inhibitors DRM (K103N), whereas the fourth had nucleoside reverse transcriptase inhibitors DRM (M184V). Results from this preliminary study show that drug resistance among ART-naive children is a problem in Ibadan. Pretreatment drug resistance testing is desirable in children before initiation of ART to guide effective treatment.
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Fármacos Anti-VIH , Infecciones por VIH , VIH-1 , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/uso terapéutico , Niño , Farmacorresistencia Viral/genética , Genotipo , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/epidemiología , VIH-1/genética , Humanos , Mutación , NigeriaRESUMEN
This article evaluates the evidence supporting use of the tenofovir disoproxil fumarate (TDF) plus lamivudine (3 âTC) combination as a dual nucleoside backbone within a triple drug antiretroviral regimen. Key trials that assess the relative efficacy, safety and resistance profile of 3 âTC and emtricitabine (FTC) are discussed. Clinical use of 3 âTC and FTC with two tenofovir prodrugs -TDF and tenofovir alafenamide (TAF) - is presented. Recommendations from various international guidelines for the construction of triple and emerging dual regimens are summarised. In conclusion, data suggest the therapeutic equivalence of 3 âTC and FTC, especially when 3 âTC is combined with TDF.
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The success of antiretroviral therapy (ART) has improved the survival of HIV-infected patients significantly. However, significant numbers of patients on ART whose HIV disease is well controlled show peripheral sensory neuropathy (PSN), suggesting that ART may cause PSN. Although the nucleoside reverse transcriptase inhibitors (NRTIs), one of the vital components of ART, are thought to contribute to PSN, the mechanisms underlying the PSN induced by NRTIs are unclear. In this study, we developed a Drosophila model of NRTI-induced PSN that recapitulates the salient features observed in patients undergoing ART: PSN and nociceptive hypersensitivity. Furthermore, our data demonstrate that pathways known to suppress PSN induced by chemotherapeutic drugs are ineffective in suppressing the PSN or nociception induced by NRTIs. Instead, we found that increased dynamics of a peripheral sensory neuron may possibly underlie NRTI-induced PSN and nociception. Our model provides a solid platform in which to investigate further mechanisms of ART-induced PSN and nociceptive hypersensitivity.This article has an associated First Person interview with the first author of the paper.