The role of antiretrovirals and drug resistance in vertical transmission of HIV-1 infection

HIV-1 proteins, Tat and gp120, target the developing dopamine system

In 2014, 3.2 million children (< 15 years of age) were estimated to be living with HIV and AIDS worldwide, with the 240,000 newly infected children in the past year, i.e., another child infected approximately every two minutes [1]. The primary mode of HIV infection is through mother-to-child transmission (MTCT), occurring either in utero, intrapartum, or during breastfeeding. The effects of HIV-1 on the central nervous system (CNS) are putatively accepted to be mediated, in part, via viral proteins, such as Tat and gp120. The current review focuses on the targets of HIV-1 proteins during the development of the dopamine (DA) system, which appears to be specifically susceptible in HIV-1-infected children. Collectively, the data suggest that the DA system is a clinically relevant target in chronic HIV-1 infection, is one of the major targets in pediatric HIV-1 CNS infection, and may be specifically susceptible during development. The present review discusses the development of the DA system, follows the possible targets of the HIV-1 proteins during the development of the DA system, and suggests potential therapeutic approaches. By coupling our growing understanding of the development of the CNS with the pronounced age-related differences in disease progression, new light may be shed on the neurological and neurocognitive deficits that follow HIV-1 infection.

Toward hyperpolarized molecular imaging of HIV: synthesis and longitudinal relaxation properties of (15) N-Azidothymidine

Previously unreported (15) N labeled Azidothymidine (AZT) was prepared as an equimolar mixture of two isotopomers: 1-(15) N-AZT and 3-(15) N-AZT. Polarization decay of (15) N NMR signal was studied in high (9.4 T) and low (~50 mT) magnetic fields. (15) N T1 values were 45 ± 5 s (1-(15) N-AZT) and 37 ± 2 s (3-(15) N-AZT) at 9.4 T, and 140 ± 16 s (3-(15) N-AZT) at 50 mT. (15) N-AZT can be potentially (15) N hyperpolarized by several methods. These sufficiently long (15) N-AZT T1 values potentially enable hyperpolarized in vivo imaging of (15) N-AZT, because of the known favorable efficient (i.e., of the time scale shorter than the longest reported here (15) N T1 ) kinetics of uptake of injected AZT. Therefore, 3-(15) N-AZT can be potentially used for HIV molecular imaging using hyperpolarized magnetic resonance imaging.

Trends in prevalence of HIV-1 drug resistance in Thailand 2009-2010

BACKGROUND

Treatment failure of antiretroviral therapy in HIV-1 infection is increasing due to development of viral resistance. Trends of resistance-associated mutation lead to the ineffective treatment in HIV-infected individuals.

METHODS

Extracted viral RNA from HIV-infected subjects in 2009 to 2010 was performed. The genotypic resistance testing was investigated for HIV-1 drug resistance in RT and PR genes. Frequencies of mutation were compared by a Fischer's exact test.

RESULTS

Three hundred and sixty-nine samples (147 in 2009 and 222 in 2010) were genotyped. At least one mutation was found in 90.8% (335/369) in PR gene and 87.0% (321/369) in RT gene. Three sequences in PR gene, M36I, H69K, and L90M, were decreased significantly in 2010 when compared to 2009. Mutations associated with resistance to nucleoside analogue reverse transcriptase inhibitors (NRTI's) were found in 61.0% and 64.2% in nonnucleoside analogue reverse transcriptase inhibitors (NNRTI's). A total of 49.6% was found in combined NRTI and NNRTI. In 2010, M41L was increased significantly from 7.5% to 14.9%. However, there was a decrease in the frequency of the mutations at position 67, 70, and 184 between 2009 and 2010.

CONCLUSIONS

In 2010, three mutations in PR gene, M36I, H69K, and L90M, were decreased significantly. However, only one mutation in RT gene, M41L was significantly increased.

A radiolabeled oligonucleotide ligation assay demonstrates the high frequency of nevirapine resistance mutations in HIV type 1 quasispecies of NVP-treated and untreated mother-infant pairs from Uganda

This study explores the levels of NVP and AZT resistance mutations in untreated, NVP- or AZT-treated mother-infant pairs in Uganda. PCR-amplified reverse transcriptase (RT) gene fragments derived from PBMC samples of 85 mothers (10 AZT treated, 35 NVP treated, and 40 untreated) and their 52 infected infants (5 AZT, 9 NVP, and 38 untreated) were classified as subtype A (59%), D (29%), C (3%), and recombinant forms (9%) by population sequencing. Only 16% of the NVP-treated infected mothers and infants harbored either the K103N or the Y181C at 6 weeks postdelivery. The majority of these samples (n = 107) were then analyzed using a radiolabeled oligonucleotide ligation assay (OLA) specific for K70R, K103N, and Y181C, using nonstandard bases to accommodate sequence heterogeneity. By OLA, 43% of the NVP-treated group had K103N and/or Y181C mutations in their HIV-1 population, using >0.6% cutoff based on a comparative clonal analysis of clinical isolates. Surprisingly, an equal fraction of the untreated and NVP-treated mother-infant group had the K103N mutation in their HIV-1 population in the range of 0.6-5%. These findings suggest a relatively high frequency of K103N mutation in the drug-naive, subtype A and D infected Ugandan population as compared to the very low frequency of the Y181C and K70R mutation (<0.6%). The prevalence of the K103N mutations may be related to its low fitness cost and high genetic stability. The persistence of these mutations may reduce the effectiveness of subsequent NVP use in treatment or prevention of perinatal transmission.

Sensitive oligonucleotide ligation assay for low-level detection of nevirapine resistance mutations in human immunodeficiency virus type 1 quasispecies

This study has adapted the oligonucleotide ligation assay (OLA) to probe for low-level nevirapine (NVP) resistance mutations K103N and Y181C in the human immunodeficiency virus type 1 (HIV-1) population of infected mother-infant pairs from Uganda. When NVP is used to prevent perinatal transmission, NVP-resistant HIV-1 clones may be rapidly selected due to a low barrier for mutation and a relatively high level of fitness (compared to that of other drug-resistant HIV-1 clones). Monitoring for even a low frequency of NVP resistance mutations may help predict the success of subsequent treatment or warrant the use of another regimen to prevent transmission in a subsequent pregnancy. The standard OLA was optimized by using nonstandard bases in oligonucleotides to allow promiscuous base pairing and accommodate significant HIV-1 heterogeneity. Radiolabeled as opposed to fluorescently tagged oligonucleotides increased the sensitivity, whereas alteration of the template, oligonucleotides, salt, and thermostable DNA ligase concentrations increased the specificity for the detection of minority codons. This modified OLA is now capable of detecting mutants with the K103N or the Y181C mutation present in an HIV-1 population at a frequency of approximately 0.4% and is at least 10- to 30-fold more sensitive than the original protocol. A cohort of 19 Ugandan mothers who received NVP treatment perinatally were sampled 6 weeks postdelivery. Ten of 19 HIV-1 DNA samples extracted from peripheral blood mononuclear cells had a detectable K103N (0.5 to 44%) or Y181C (0.8 to 92.5%) mutation, but only one plasma HIV-1 RNA sample had a viral population with the Y181C mutation. These findings suggest that OLA is a robust, sensitive, and specific method for the detection of low-frequency drug resistance mutations in an intrapatient HIV-1 population.

“Nanobacterium sanguineum” – Is it a new life-form in search of human ailment or commensal: Overview of its transmissibility and chemical means of intervention

Morphological, cultural, and immuno-histochemical characteristics of "Nanobacterium sanguineum" (NB) described in the literature are reviewed. NB is reported to be a motile, Gram negative organism that divides by binary fission within a calcium-coated slimy shell; this yeast-like shell replicates by budding. It measures between 20 and 200 nm with a unique structure containing 16S ribosomal RNA. NB has been observed by electron microscopy in coronary artery plaques (CAD) and in kidney stones (KS) found in renal diseases. On the basis of supportive literature, we suggest that NB is not only present in the human body but also has auxiliary association with human ailments without a specific etiological role; anti-NB antibody has been detected in subjects with calcified lesions and inflammation in diverse ailments including choriodecidual inflammation in pregnancy, ovarian cancers, arthritis and even Alzheimer's disease. More recent report on the detection and vertical transmission of NB antigen and anti-NB antibody in HIV-infected mothers supports the view that NB might be an important opportunistic infective agent contributing to HIV pathology; we note that the presence of viable and transmitting NB was not studied and suggest further studies to establish vertical transmission of NB in HIV-infected persons. On the basis of the foregoing we suggest that NB possibly exacerbates human ailments and raise the question: Is NB a new life-form in search of human ailment or a commensal organism? Recognizing the presence of NB in the human body, we discuss clinical trials, reported in the literature relevant to its eradication, with a rectal suppository containing very high amounts of disodium EDTA and tetracycline. We suggest that tetracycline in this formulation acted in combination with EDTA, more as a chelating agent than an antibiotic; oxytetracycline- a non-chelating form of tetracycline-does not inhibit or kill NB. Evaluation of anti-NB effect of orally administrable and potentially safer as well as therapeutically more acceptable chelating agent -ascorbic acid, acting alone or in combination with antibiotics-that eradicates another slime forming bacterium - Pseudomonas aeruginosa - in children with cystic fibrosis, is suggested.

[HIV drug resistance and optimization of antiviral treatment in resource-poor countries]

HIV drug resistance has been associated with treatment failure in Western countries but the lessons learned can be useful in optimization of highly active antiretroviral treatment (HAART) in resource-poor settings. There is a need to improve access to HAART in such regions, but appropriate strategies must be rapidly implemented, such as adapted programs to facilitate adherence to therapy, rational use of genotypic drug resistance monitoring in specific situations, and use of alternative treatment regimens. The implications of HIV genetic diversity must also be considered in management of drug resistance.

Diversity of human immunodeficiency virus type 1 subtype A and CRF03_AB protease in Eastern Europe: selection of the V77I variant and its rapid spread in injecting drug user populations

To characterize polymorphisms of the subtype A protease in the former Soviet Union, proviral DNA samples were obtained, with informed consent, from 119 human immunodeficiency virus type 1 (HIV-1)-positive untreated injecting drug users (IDUs) from 16 regions. All individuals studied have never been treated with antiretroviral drugs. The isolates were defined as IDU-A (n = 115) and CRF03_AB (n = 4) by using gag/env HMA/sequencing. The pro region was analyzed by using sequencing and original HIV-ProteaseChip hybridization technology. The mean of pairwise nucleotide distance between 27 pro sequences (23 IDU-A and 4 CRF03_AB) was low (1.38 +/- 0.79; range, 0.00 to 3.23). All sequences contained no primary resistance mutations. However, 13 of 23 (56.5%) subtype A isolates bore the V77I substitution known as the secondary protease mutation. V77I was associated with two synonymous substitutions in triplets 31 and 78, suggesting that all V77I-bearing viruses evolved from a single source in 1997. Hybridization analysis showed that 55 of 115 (47.8%) HIV-1 isolates contained V77I, but this variant was not found in any of 31 DNA samples taken from regions, where the HIV-1 epidemic among IDUs started earlier 1997, as well as in any of four CRF03_AB isolates. The results of analysis of 12 additional samples derived from epidemiologically linked subjects showed that in all four epidemiological clusters the genotype of the donor and the recipients was the same irrespective of the route of transmission. This finding demonstrates the transmission of the V77I mutant variant, which is spreading rapidly within the circulating viral pool in Russia and Kazakhstan. The continued molecular epidemiological and virological monitoring of HIV-1 worldwide thus remains of great importance.

Developing a directly administered antiretroviral therapy intervention for HIV-infected drug users: implications for program replication

Directly administered antiretroviral therapy (DAART) is one approach to improving adherence to among human immunodeficiency virus (HIV)-infected drug users. We evaluated the essential features of a community-based DAART intervention in a randomized, controlled trial of DAART versus self-administered therapy. Of the initial 72 subjects, 78% were racial minorities, and 32% were women. Social and medical comorbidities among subjects included homelessness (35% of subjects), lack of interpersonal support (86%), major depression (57%), and alcoholism (36%). At baseline, the median CD4+ cell count was 403 cells/mL and the median HIV-1 RNA load was 146,333 copies/mL (log10 5.31 copies/mL). During the prior 6 months, 33% of subjects had missed a medical appointment, and 47% had visited an emergency department. Although most subjects (67%) preferred to take their own medications, 76% would accept DAART if it were made compulsory. A methadone clinic was the DAART venue acceptable to the fewest subjects (36%), and a mobile syringe-exchange program was acceptable to the most subjects (83%). Adherence was higher for supervised than for unsupervised medication administration (P<.0001), a finding that supports use of daily supervision of once-daily regimens. Moreover, DAART should incorporate enhanced elements such as convenience, flexibility, confidentiality, cues and reminders, responsive pharmacy and medical services, and specialized training for staff.

Jewish religious ethics mandate access to antiretroviral drugs in developing countries

The plight of millions of HIV-infected individuals without access to antiretroviral (ARV) medications constitutes an enormous problem. Religious values can influence policymakers in public and personal health issues. This article posits that Jewish religious law mandates the broadest possible access to ARV medications for HIV-infected individuals, and argues that wealthy countries must assist poorer ones to facilitate access.

Rates of transmission of antiretroviral drug resistant strains of HIV-1

BACKGROUND

It is clear that transmission of drug resistant HIV-1 is possible and occurs regularly. However, there is a lack of clarity concerning the true rate of this transmission in a given population, the impact of combination therapies on this rate, and the contribution of transmitted resistant virus to treatment failure either in an individual or on a population basis.

OBJECTIVES

To provide a review of our current understanding of rates of transmission of drug resistant HIV-1 in various populations and to report the results of a study conducted to determine this rate in Sydney, Australia in the years 1992-2000.

STUDY DESIGN

A review of the literature combined with a prospective study of antiretroviral drug resistance in 130 individuals who were diagnosed with symptomatic primary infection at St. Vincent's Hospital, Sydney, Australia between 1992 and 2000. Sequencing of reverse transcriptase (RT) and protease (PR) was performed by the TruGene HIV-1 genotyping kit (Visible Genetics Inc.).

RESULTS

The results found in the Sydney population contrast with much of the literature. The prevalence of mutations that conferred primary resistance to protease inhibitors (PIs) was only 0.8% at position V82I. Secondary mutations/polymorphisms were seen in the PR at position L10I/V, K20R, M36I, L63P, A71T/V, or V77I in 60%. L63P was the most frequently found mutation (46.3%). The incidence of protease-resistant strains of HIV in primary HIV-1 infection did not change after the introduction of PIs in 1996. The distribution of the most common resistance mutations in the RT was as follows; M41L (8.5%) and T215Y (8.5%) and K70R (4.8%). The frequency of mutations associated with NRTI resistance was significantly lower in the post 1995 samples (43.9 vs. 19.1%, P < 0.05). Moreover, both M41L and K70R, but not T215Y, occurred with significantly decreased frequency in the post 1995 samples.

CONCLUSIONS

In contrast to other studies we found no increase in the rate of PR resistance and a decrease in the rate of RT resistance in recently transmitted virus over the period 1992-2000. The reasons for the differences between these results and those reported from elsewhere may relate to treatment regimens used in the transmitting population and may have implications for treatment policies in this country.

Zidovudine (AZT) treatment suppresses granulocyte-monocyte colony stimulating factor receptor type alpha (GM-CSFR alpha) gene expression in murine bone marrow cells

In vitro exposure of murine bone marrow cells to increasing concentrations of zidovudine (AZT, 0.1-50 microM) had a concentration dependent suppressive effect on the growth of granulocyte-monocyte colony forming unit (CFU-GM) derived colonies. In our previous published study, the mechanism of AZT-induced suppression of erythroid colony forming unit (CFU-E) derived colonies was linked to a decrease in erythropoitin receptor (Epo-R) gene expression. In this study, we have observed that AZT exposure also induced a concentration dependent suppressive effect (35-90%) on GM-CSF receptor type alpha (GM-CSFR alpha) gene expression. The suppression of GM-CSFR alpha mRNA expression was specific, since AZT caused a much lower decrease (15-22%) on the IL-3 receptor type alpha (IL-3R alpha) message level, and had an insignificant effect on glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and c-myc message levels. Erythropoietin (Epo) therapy has been used for reversal of AZT induced erythroid toxicity. Exposure to increasing concentrations (10-500 U/ml) of GM-CSF was unable to override the suppressive effect of AZT on CFU-GM derived colonies, however, treatment in combination with IL-3 (10-250 U/ml) ameliorated the suppressive effects of AZT on CFU-GM and on GM-CSFR alpha and IL-3R alpha gene expression. These findings suggest a mechanism via which AZT may suppress granulocyte-monocyte specific differentiation in murine bone marrow cells. These data also suggest that a combination of GM-CSF and IL-3 may be a superior therapeutic intervention for AZT-induced neutropenia.

HIV drug resistance and implications for the introduction of antiretroviral therapy in resource-poor countries

The development and transmission of HIV drug-resistant viruses is of serious concern and has been shown to significantly diminish the effectiveness of antiretroviral therapy. In addition, cross-resistance between drugs of the same class can seriously limit therapeutic options and may potentially be most problematic in resource-poor settings where new drugs are not widely available. Strategies based on avoidance of virological failure are therefore essential for the long-term success of therapy. In this regard, regionally adapted programs to facilitate proper adherence with therapy need to be urgently implemented, concomitant with expanded access to new antiretroviral drugs. The value of genotypic resistance testing as a prognostic tool to help guide therapeutic decisions has been established. However, the relatively high cost of this novel technology does not warrant its routine utilization at this time in resource-poor countries. Lastly, the genetic barrier of the antiretroviral agents that are prescribed is also an important consideration that needs to be integrated with knowledge of HIV-1 subtypes, drug pharmacology, and medical management of concurrent illnesses. The selection of appropriate first-line antiretroviral combination regimens may be an even more important consideration in developing than developed countries, given that options in the aftermath of treatment failure may be more limited in such settings.