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Background: sCD163< a biomarker of monocyte-macrophage activation< has been identified as a predictor of all-cause mortality in treated HIV-infected individuals. Nevertheless< little is known about whether different antiretroviral drugs differentially regulate sCD163 levels and monocyte activation. Methods: A total of 123 patients receiving zidovudine (ZDV)- based (n = 55) or tenofovir disoproxil fumarate (TDF)-based (n = 68) antiretroviral regimens were enrolled< and their viral loads< CD4 counts< as well as plasma sCD163 and sCD14 levels were quantified. Twenty-eight (14 in each group) patients donated additional blood samples for flow cytometry and gene expression analyses using purified monocytes. THP-1 cultures were also used to investigate the effect of ZDV on ADAM17< which is responsible for CD163 shedding. Results: As compared to the TDF-treated group< the ZDV-treated group had lower plasma sCD163 levels and higher CD163 expression on CD14++CD16- monocytes. Five metabolicinflammatory genes exhibited significantly different expression levels between purified monocytes of the ZDV and TDF groups (IL-6< 2.90-fold lower in ZDV group< P < 0.001; iNOS< 1.81-fold higher; CX3CR1< 1.72-fold lower; MIP-1b< 1.10-fold lower; and PPARg-1< 1.36-fold higher< P < 0.05). Moreover< we show that ZDV treatment increases the surface expression of CD163 in cultured THP-1 cells< accompanied by the inhibition of glycosylation and surface expression of ADAM17. Conclusions: Compared with TDF treatment< ZDV treatment causes lower plasma sCD163 levels< probably by inhibiting the glycosylation of ADAM17 and CD163 shedding. Our results show that ZDV functions as an ADAM17 inhibitor in vivo and extend our understanding of its immune-modulatory effects and adverse effects. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the efficacy of the antiretrovirals: Zidovudine (ZDV) alone; ZDV + Recombinant Human Interferon-α (rHuIFN-α); ZDV + Lamivudine (3TC) and ZDV + valproic acid (Valp) on naturally feline immunodeficiency virus (FIV)-infected cats, in the late phase of the asymptomatic stage of infection. The follow-up was performed over one year, through clinical evaluation and the determination of viral loads and CD4+/CD8+ ratios. Neurological signs were studied by visual and auditory evoked potentials (VEP, AEP) and the responses were abnormal in 80% of the FIV-infected cats. After one year, an improvement in VEP and AEP was observed in the ZDV + Valp group and a worsening in the group receiving ZDV + rHuIFN-α. The CD4+/CD8+ ratio showed a significant increase (both intra and inter-groups) only in ZDV and ZDV + 3TC, between their pre-treatment and one year values, as well as among the other groups. Viral load only showed a significant decrease in ZDV and ZDV + 3TC groups, when comparing the values at one year of treatment vs. pre-treatment values and when the different groups were compared. In addition, the viral load decrease was significantly more pronounced in the ZDV + 3TC vs. ZDV group. We conclude that ZDV and ZDV + 3TC produce significant reductions in viral load and stimulate a recovery of the CD4+/CD8+ ratio, compared with the other protocols. It is clear that the addition of 3TC resulted in a greater reduction in viral load than use of ZDV as a single drug. Therefore, the combination ZDV + 3TC could be more effective than the sole use of ZDV.

Background: Antiretroviral drugs including zidovudine (ZDV) are effective in reducing HIV mother to child transmission (MTCT), however safety concern remains. The optimal duration of postnatal ZDV has not been established in clinical studies and there is a lack of consensus regarding optimal management. The objective of this study was to investigate the effectiveness and safety of a risk adapted two week course of oral postnatal ZDV as part of a combined intervention to reduce MTCT. Methods: 118 mother infant pairs were treated according to the German-Austrian recommendations for HIV therapy in pregnancy and in HIV exposed newborns between 2000-2010. In the absence of factors associated with an increased HIV-1 transmission risk, children were assigned to the low risk group and treated with an abbreviated postnatal regimen with oral ZDV for 2 weeks. In the presence of risk factors, postnatal ZDV was escalated accordingly. Results: Of 118 mother-infant pairs 79 were stratified to the low risk group, 27 to the high risk group and 11 to the very high risk group for HIV-1 MTCT. 4 children were lost to follow up. Overall Transmission risk in the group regardless of risk factors and completion of prophylaxis was 1.8% (95% confidence interval (CI) 0.09-6.6). If transmission prophylaxis was complete, transmission risk was 0.9% (95% CI 0.01-5.7). In the low risk group receiving two week oral ZDV transmission risk was 1.4% (95% CI 0.01-8.4) Conclusion: These data demonstrate the effectiveness of a short neonatal ZDV regimen in infants of women on stable ART and effective HIV-1 suppression. Further evaluation is needed in larger studies [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the efficacy of the antiretrovirals: Zidovudine (ZDV) alone; ZDV + Recombinant Human Interferon-α (rHuIFN-α); ZDV + Lamivudine (3TC) and ZDV + valproic acid (Valp) on naturally feline immunodeficiency virus (FIV)-infected cats, in the late phase of the asymptomatic stage of infection. The follow-up was performed over one year, through clinical evaluation and the determination of viral loads and CD4+/CD8+ ratios. Neurological signs were studied by visual and auditory evoked potentials (VEP, AEP) and the responses were abnormal in 80% of the FIV-infected cats. After one year, an improvement in VEP and AEP was observed in the ZDV + Valp group and a worsening in the group receiving ZDV + rHuIFN-α. The CD4+/CD8+ ratio showed a significant increase (both intra and inter-groups) only in ZDV and ZDV + 3TC, between their pre-treatment and one year values, as well as among the other groups. Viral load only showed a significant decrease in ZDV and ZDV + 3TC groups, when comparing the values at one year of treatment vs. pre-treatment values and when the different groups were compared. In addition, the viral load decrease was significantly more pronounced in the ZDV + 3TC vs. ZDV group. We conclude that ZDV and ZDV + 3TC produce significant reductions in viral load and stimulate a recovery of the CD4+/CD8+ ratio, compared with the other protocols. It is clear that the addition of 3TC resulted in a greater reduction in viral load than use of ZDV as a single drug. Therefore, the combination ZDV + 3TC could be more effective than the sole use of ZDV. [ABSTRACT FROM AUTHOR]

The remarkable sensitivity of accelerator mass spectrometry (AMS) is finding many new applications in pharmacology. In this study AMS was used to measure [14C]-Zidovudine (ZDV) concentrations at the drug's site of action (peripheral blood mononuclear cells, PBMCs) following a dose of 520 ng (less than one-millionth of the standard daily dose) to a healthy volunteer. In addition, the pharmacokinetics of this microdose were determined and compared to previously published parameters for therapeutic doses. Microdose ZDV pharmacokinetic parameters fell within reported 95% confidence intervals or standard deviations of most previously published values for therapeutic doses. Blood, urine, stool, saliva, and isolated PBMCs were collected periodically through 96 h postdose and analyzed for ZDV and metabolite concentrations. The results showed that ZDV is rapidly absorbed and eliminated, has one major metabolite, and is sequestered in PBMCs. 14C mass balance assessments indicated a significant portion of ZDV remained after 96 h with a much prolonged elimination half-life. Results of this study demonstrate the usefulness of microdosing and AMS as a tool for studying the pharmacokinetic characteristics, including PBMC concentrations, of ZDV and underscore the value of AMS as a tool with which to perform pharmacokinetic and mass balance studies using trace amounts of radiolabeled compound. © 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 97:2833–2843, 2008 [ABSTRACT FROM AUTHOR]

AZT remains an important drug to combat HIV infection in combination with other nucleoside analogs. However, long-term treatment with nucleoside analogs can result in mitochondrial toxicity, which can be fatal in some forms. We review the metabolic pathway for AZT transport and phosphorylation within mitochondria and its interaction with the mitochondrial DNA polymerase, Pol-γ. Suggested mechanisms for the mitochondrial toxicity of AZT related to this metabolism are discussed. Finally we review recent evidence that the HIV virus itself is involved in the toxicity of AZT. iubmb Life , 58: 403–408, 2006 [ABSTRACT FROM AUTHOR]

Cellular efflux and uptake transports of several anti-HIV agents are mediated by plasma membrane-localized solute transporters. However, transporters involved in raltegravir disposition have not been fully characterized. Here, we performed in vitro studies to identify transporters mediating transcellular transport of raltegravir. Transepithelial raltegravir transport was examined using porcine kidney epithelial cell line (LLC-PK1) and LLC-PK1 cells stably transfected with P-glycoprotein (also known as Multiple drug resistance 1) (L-MDR1). Transepithelial transport of raltegravir in Caco-2 cell monolayers, and intracellular accumulation of raltegravir in the MT-2 and MT-4 (CD4+ T-) cells were measured in the presence or absence of anti-HIV agents. The uptake of raltegravir was investigated in HEK-293 cells expressing each of several solute carrier family transporters. The apical-to-basal raltegravir transport was significantly decreased in L-MDR1 as compared to that in LLC-PK1 monolayers. In HEK-293 cells expressing breast cancer resistance protein (BCRP), raltegravir accumulation was lower than that in the mock-transfected cells. In Caco-2 cells, protease inhibitors including nelfinavir, ritonavir and lopinavir enhanced the apical-to-basal transport of raltegravir. By contrast, reverse transcriptase inhibitors such as zidovudine, efavirenz, and nevirapine, had no effect on raltegravir transport. The cellular accumulation of raltegravir in MT-2 cells, which express P-glycoprotein, was significantly increased in the presence of protease inhibitors. By contrast, protease inhibitors only marginally increased the accumulation of raltegravir in MT-4 cells, in which P-glycoprotein is not expressed. The present findings suggest that raltegravir is a substrate of both P-glycoprotein and BCRP. Protease inhibitors increase the absorptive transport of raltegravir in Caco-2 cells, and the cellular accumulation in T-cells, at least in part, by P-glycoprotein-mediated interaction., (Copyright © 2013 Elsevier Inc. All rights reserved.)