The increasing prevalence of acquired and transmitted HIV-1 drug resistance is an obstacle to successful antiretroviral therapy (ART) in the low- and middle-income countries (LMICs) hardest hit by ...the HIV-1 pandemic. Genotypic drug resistance testing could facilitate the choice of initial ART in areas with rising transmitted drug resistance (TDR) and enable care-providers to determine which individuals with virological failure (VF) on a first- or second-line ART regimen require a change in treatment. An inexpensive near point-of-care (POC) genotypic resistance test would be useful in settings where the resources, capacity, and infrastructure to perform standard genotypic drug resistance testing are limited. Such a test would be particularly useful in conjunction with the POC HIV-1 viral load tests that are currently being introduced in LMICs. A POC genotypic resistance test is likely to involve the use of allele-specific point mutation assays for detecting drug-resistance mutations (DRMs). This study proposes that two major nucleoside reverse transcriptase inhibitor (NRTI)-associated DRMs (M184V and K65R) and four major NNRTI-associated DRMs (K103N, Y181C, G190A, and V106M) would be the most useful for POC genotypic resistance testing in LMIC settings. One or more of these six DRMs was present in 61.2% of analyzed virus sequences from ART-naïve individuals with intermediate or high-level TDR and 98.8% of analyzed virus sequences from individuals on a first-line NRTI/NNRTI-containing regimen with intermediate or high-level acquired drug resistance. The detection of one or more of these DRMs in an ART-naïve individual or in a individual with VF on a first-line NRTI/NNRTI-containing regimen may be considered an indication for a protease inhibitor (PI)-containing regimen or closer virological monitoring based on cost-effectiveness or country policy.
HIV infection is often associated with liver failure, which alters the pharmacokinetics of many drugs. In this study we investigated whether acute liver failure （ALF） altered the pharmacokinetics of ...the first-line anti-HIV agent zidovudine （AZT）, a P-gp/BCRP substrate, in rats. ALF was induced in rats by injecting thioacetamide （TAA, 300 mg·kg1·d-1, ip） for 2 days. On the second day after the last injection of TAA, the pharmacokinetics of AZT was investigated following both oral （20 mg/kg） and intravenous （10 mg/kg） administration. ALF significantly increased the plasma concentrations of AZT after both oral and intravenous doses of AZT, but without affecting the urinary excretion of AZT. AZT metabolism was studied in rat hepatic microsomes in vitro, which revealed that hepatic UGT2B7 was the main enzyme responsible for the formation of AZT O-glucuronide （GAZT）; ALF markedly impaired AZT metabolism in hepatic microsomes, which was associated with the significantly decreased hepatic UGT2B7 expression. Intestinal absorption of AZT was further studied in rats via in situ single-pass intestinal perfusion. Intestinal P-gp function and intestinal integrity were assessed with rhodamine 123 and FD-70, respectively. We found that ALF significantly downregulated intestinal P-gp expression, and had a smaller effect on intestinal BCRP. Further studies showed that ALF significantly increased the intestinal absorption of both rhodamine 123 and AZT without altering intestinal integrity, thus confirming an impairment of intestinal P-gp function. In conclusion, ALF significantly increases the oral plasma exposure of AZT in rats, a result partly attributed to the impaired function and expression of hepatic UGT2B7 and intestinal P-gp.
One of the most frequent comorbidities of HIV infection is depression, with a lifetime prevalence of 22 to 45%. Therefore, it was decided to study a potential pharmacokinetic interaction between the ...nonnucleoside reverse transcriptase inhibitor nevirapine (NVP) and the tricyclic antidepressant nortriptyline (NT). NVP and NT were administered to rats either orally, intraduodenally, or intravenously, and the changes in plasma levels and pharmacokinetic parameters were analyzed. Experiments with rat and human hepatic microsomes were carried out to evaluate the inhibitory effects of NT on NVP metabolism. NVP plasma concentrations were significantly higher when this drug was coadministered with NT. The maximum plasma concentrations of NVP were increased 2 to 5 times and the total plasma clearance was decreased 7-fold in the presence of NT. However, statistically significant differences in the pharmacokinetic parameters of NT in the absence and presence of NVP were not found. In vitro studies with rat and human hepatic microsomes confirmed the inhibition of NVP hepatic metabolism by NT in a concentration-dependent way, with the inhibition being more intense in the case of rat microsomes. In conclusion, a pharmacokinetic interaction between NVP and NT was detected. This interaction was a consequence of the inhibition of hepatic metabolism of NVP by NT. In vivo human studies are required to evaluate the effects of this interaction on the pharmacokinetics of NVP before it can be taken into account for patients receiving NVP.
The combined pharmacological approach to the treatment of HIV infection, known as highly active antiretroviral therapy (HAART), has dramatically reduced AIDS-related morbidity and mortality. However, ...its use has been associated with serious adverse reactions, of which those resulting from mitochondrial dysfunction are particularly widespread. Nucleos(t)ide-reverse transcriptase inhibitors (NRTIs) have long been considered the main source of HAART-related mitochondrial toxicity due to their ability to inhibit Pol-γ, the DNA polymerase responsible for the synthesis of mitochondrial DNA. Nevertheless, accumulating evidence points to a more complex relationship between these organelles and NRTIs. Also, alternative pathways by which other groups of anti-HIV drugs (non-nucleoside reverse transcriptase inhibitors and protease inhibitors) interfere with mitochondria have been suggested, although their implications, both pharmacological and clinical, are open to debate. This review aims to provide a comprehensive overview of the mechanisms and factors which influence the mitochondrial involvement in the toxicity of all three major classes of anti-HIV drugs.
Background:
With the increasing coverage of antiretroviral therapy, concerns for the emergence and transmission of HIV drug resistance (HIVDR) are arising. HIVDR was divided into 5 levels: sensitive, ...potentially resistant, low resistant, intermediate resistant, and high resistant. Most of the articles on HIVDR involved low-level, intermediate-level, and high-level drug resistance to antiretroviral drug, and few articles deal with potential drug resistance. Treatment failure associated with the level of low-level, intermediate-level, and high-level resistance to antiretroviral drug has been reported. However, whether virological failure (VF) is related to potential resistance remains unclear. In this study, we aimed to describe the situation of potential resistance to antiretroviral drug and whether it is related to VF.
Methods:
We analyzed the demographic, behavioral information, medical history, and drug resistance–associated mutation data from subjects. Drug resistance mutations at baseline and time of failure in patients suffering VF were detected by using the Vela automated next-generation sequencing platform. The χ
2
test or Fisher exact test and logistic regression were used to assess the risk factors that contribute to VF in the potential drug-resistant people.
Results:
The prevalence of overall pretreatment drug resistance was 7.06% (233/3300), and the prevalence of pretreatment potential resistance was 8.79% (290/3300). All these patients with pretreatment potential first-line drugs resistance showed potential resistance to nonnucleoside reverse transcriptase inhibitors (NNRTIs), and some of them had potential drug resistance to NNRTIs and NRTIs or NNRTIs and PIs; among these patients, 94.71% (179/189) had V179 D/E mutations. The VF rate of first-line treatment for potentially resistant people is 17.99%. CD4
+
T-cell count ≤200 cells/L at antiretroviral therapy initiation are risk factors for the failure of first-line treatment.
Conclusions:
The prevalence of potential drug resistance among individuals with HIV and the VF rate of first-line treatment for potential drug-resistant people were high. To better optimize clinical management, prevention, and control of HIV, attention should be devoted to the potential resistance of nonnucleoside drugs.
Telomere DNA in human cells shortens during each round of DNA replication. In cancer cells, telomere shortening is compensated by telomerase or the alternative lengthening of telomere (ALT) mechanism ...to maintain cell division potential. The G-rich strand of telomere DNA can fold into a G-quadruplex structure and disrupt these two processes. Therefore, stabilization of the G-quadruplex by chemical ligands is emerging as a promising anticancer strategy. So far, in vitro studies on such ligands are exclusively carried out in dilute solutions. However, the intracellular environment is highly crowded with biomolecules. How G-quadruplex ligands behave under molecular crowding condition is critical for their in vivo anticancer effect. In this work, we studied several ligands for their ability to stabilize the telomere G-quadruplex and inhibit telomerase under both dilute and crowding conditions. Surprisingly, the ligands became significantly less effective or even lost the ability to stabilize the G-quadruplex and inhibit telomerase under crowding conditions. Our data attributed this consequence to the decreased binding affinity of ligands to the G-quadruplex as a result of reduced water activity and increased viscosity of the medium associated with molecular crowding. This effect is irrelevant to and overweighs the influences from other factors such as the G-quadruplex structure, cation, and ligand species. Our work illustrates a possibility that molecular crowding inside cells may reduce or limit the potency of ligands although they may be effective in dilute solution, thus strongly arguing for the necessity of evaluating ligands under more physiologically relevant conditions and designing drugs with this concern in mind.
Numerous structurally different non-nucleoside compounds have been evaluated for their inhibitory effects against HIV replication, in which DABO derivatives, bearing the ...dihydro-alkoxyl-benzyl-oxopyrimidine scaffold, have been identified as a particular class of non-nucleoside reverse transcriptase inhibitors (NNRTIs). The S-DABO, NH-DABO, -N-DABO, DATNO and DACO analogs represent various structural chemical modifications of the substituents on C2, C6 and C5 of the pyrimidine ring to obtain potentially higher potency and lower cytotoxicity. This review article describes the recent progress of the chemical modifications and structure-activity relationship studies of DABO derivatives and provides new clues for the design of new DABO congeners.
A novel series of uracil-bearing DAPYs derivatives were designed and synthesized via structure-based molecular hybridization to discover compounds with improved anti-resistance profiles. Anti-HIV ...activity of the designed compounds was tested in MT-4 cell cultures. The most promising compound 16d showed excellent activity with EC50 value of 5.6 nM against wide-type HIV-1 and low cytotoxicity (SI > 50000). Activity against the clinic prevalent mutant strains was also tested, suggesting that 16d was sensitive to E138K (EC50 = 34.2 nM). Primary drug-like properties, such as water solubility and logP, were evaluated by experiment or calculation, which indicated that introducing an uracil can improve solubility. The molecular modeling accompanied with the preliminary SAR correlations paved the way for the next round of rational design of potent anti-HIV agents.
By structure-based molecular hybridization, a new HIV-1 NNRTI 16d was discovered with excellent activity and high selectivity. Display omitted
•Novel uracil-bearing DAPYs derivatives were identified.•16d exhibited best activity with EC50 values of 5.6 nM (wt) and 34.2 nM (E138K).•LogP and water solubility of representative compounds were measured.•Preliminary SARs and molecular simulation of these new analogues were detailed.
Introduction
A potential concern with the use of dapivirine (DPV) for HIV prevention is the selection of a drug‐resistant virus that could spread and reduce the effectiveness of non‐nucleoside ...reverse transcriptase (NNRTI)‐based first‐line antiretroviral therapy. We evaluated HIV‐1 seroconversions in MTN‐020/ASPIRE for selection of drug resistance and evaluated the genetic basis for observed reductions in susceptibility to DPV.
Methods
MTN‐020/ASPIRE was a placebo‐controlled, Phase III safety and effectiveness study of DPV ring for HIV‐1 prevention conducted at 15 sites in South Africa, Zimbabwe, Malawi and Uganda between 2012 and 2015. Plasma from individuals who seroconverted in ASPIRE was analysed for HIV‐1 drug resistance using both population Sanger sequencing and next‐generation sequencing (NGS) with unique molecular identifiers to report mutations at ≥1% frequency. DPV susceptibility of plasma‐derived recombinant HIV‐1 containing bulk‐cloned full‐length reverse transcriptase sequences from MTN‐020/ASPIRE seroconversions was determined in TZM‐bl cells. Statistical significance was calculated using the Fisher's exact test.
Results
Plasma from all 168 HIV seroconversions were successfully tested by Sanger sequencing; 57 of 71 DPV arm and 82 of 97 placebo (PLB) arm participants had NGS results at 1% sensitivity. Overall, 18/168 (11%) had NNRTI mutations including K101E, K103N/S, V106M, V108I, E138A/G, V179D/I/T and H221Y. Five samples from both arms had low‐frequency NNRTI mutations that were not detected by Sanger sequencing. The frequency of NNRTI mutations from the DPV arm (11%) was not different from the PLB arm (10%; p = 0.80). The E138A mutation was detected in both the DPV (3 of 71 4.2%) and PLB arm (5 of 97 5.2%) and conferred modest reductions in DPV susceptibility in some reverse transcriptase backgrounds but not others.
Conclusions
HIV‐1 drug resistance including NNRTI resistance did not differ between the DPV and placebo arms of the MTN‐020/ASPIRE study, indicating that drug resistance was not preferentially acquired or selected by the DPV ring and that the preventive benefit of DPV ring outweighs resistance risk.
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