AIDS Research and Therapy - Latest Articles

Reduction of the HIV-1 reservoir in resting CD4+ T-lymphocytes by high dosage intravenous immunoglobulin treatment: a proof-of-concept study

Annica Lindkvist — 2009-07-01T00:00:00Z

Background: The latency of HIV-1 in resting CD4+ T-lymphocytes constitutes a major obstacle for the eradication of virus in patients on antiretroviral therapy (ART). As yet, no approach to reduce this viral reservoir has proven effective. Methods: Nine subjects on effective ART were included in the study and treated with high dosage intravenous immunoglobulin (IVIG) for five consecutive days. Seven of those had detectable levels of replication-competent virus in the latent reservoir and were thus possible to evaluate. Highly purified resting memory CD4+ T-cells were activated and cells containing replication-competent HIV-1 were quantified. HIV-1 from plasma and activated memory CD4+ T-cells were compared with single genome sequencing (SGS) of the gag region. T-lymphocyte activation markers and serum interleukins were measured. Results: The latent HIV-1 pool decreased with in median 68% after IVIG was added to effective ART. The reservoir decreased in five, whereas no decrease was found in two subjects with detectable virus. Plasma HIV-1 RNA [greater than or equal to] 2 copies/mL was detected in five of seven subjects at baseline, but in only one at follow-up after 8-12 weeks. The decrease of the latent HIV-1 pool and the residual plasma viremia was preceded by a transitory low-level increase in plasma HIV-1 RNA and serum interleukin 7 (IL-7) levels, and followed by an expansion of T regulatory cells. The magnitude of the viral increase in plasma correlated to the size of the latent HIV-1 pool and SGS of the gag region showed that viral clones from plasma clustered together with virus from activated memory T-cells, pointing to the latent reservoir as the source of HIV-1 RNA in plasma. Conclusion: The findings from this uncontrolled proof-of-concept study suggest that the reservoir became accessible by IVIG treatment through activation of HIV-1 gene expression in latently-infected resting CD4+ T-cells. We propose that IVIG should be further evaluated as an adjuvant to effective ART.

Comparison of metal-dependent catalysis by HIV-1 and ASV integrase proteins using a new and rapid, moderate throughput assay for joining activity in solution

Mark Andrake — 2009-06-29T00:00:00Z

Background: HIV-1 integrase (IN) is an attractive target for the development of drugs to treat AIDS, and inhibitors of this viral enzyme are already in the clinic. Nevertheless, there is a continuing need to devise new approaches to block the activity of this viral protein because of the emergence of resistant strains. To facilitate the biochemical analysis of wild-type IN and its derivatives, and to measure the potency of prospective inhibitory compounds, a rapid, moderate throughput solution assay was developed for IN-catalyzed joining of viral and target DNAs, based on the detection of a fluorescent tag. Results: A detailed, step-by-step description of the new joining assay is provided. The reactions are run in solution, the products captured on streptavidin beads, and activity is measured by release of a fluorescent tag. The procedure can be scaled up for the analysis of numerous samples, and is substantially more rapid and sensitive than the standard radioactive gel methods. The new assay is validated and its utility demonstrated via a detailed comparison of the Mg++- and Mn++-dependent activities of the IN proteins from human immunodeficiency virus type 1 (HIV-1) and the avian sarcoma virus (ASV). The results confirm that ASV IN is considerably more active than HIV IN, but with both enzymes the initial rates of joining, and the product yields, are higher in the presence of Mn++ than Mg++. Although the pH optima for these two enzymes are similar with Mn++, they differ significantly in the presence of Mg++, which is likely due to differences in the molecular environment of the binding region of this physiologically relevant divalent cation. This interpretation is strengthened by the observation that a compound that can inhibit HIV-1 IN in the presence of either metal cofactors is only effective against ASV in the presence of Mn++. Conclusion: A simplified, assay for measuring the joining activity of retroviral IN in solution is described, which offers several advantages over previous methods and the standard radioactive gel analyses. Based on comparisons of signal to background ratios, the assay is 10-30 times more sensitive than gel analysis, allows more rapid and accurate biochemical analyses of IN catalytic activity, and moderate throughput screening of inhibitory compounds. The assay is validated, and its utility demonstrated in a comparison of the metal-dependent activities of HIV and ASV IN proteins.

Serum lipid profiles among patients initiating ritonavir-boosted atazanavir versus efavirenz-based regimens

Anuradha Ganesan — 2009-06-22T00:00:00Z

Background: Antiretrovirals used to treat HIV-infected patients have the potential to adversely affect serum lipid profiles and increase the risk of cardiovascular disease which is an emerging concern among HIV-infected patients. Since boosted atazanavir and efavirenz are both considered preferred antiretrovirals, a head to head comparison of their effects on serum lipids is needed.Aim: The primary objective of the study was to compare the effects of atazanavir (boosted and unboosted) and efavirenz- based regimens on serum lipid profiles.Study Design: Prospective cohort study nested within three ongoing cohorts of HIV-infected individuals.Study Population and Methods: Participants initiating either atazanavir or efavirenz-based regimens, with documented pre- and post-initiation lipid values. Multivariate linear regression was conducted to estimate adjusted mean differences between treatment groups for high density lipoprotein cholesterol (HDL-c), non-HDL-c, and log total cholesterol (TC) to HDL-c ratio outcomes; log-linear regression models were used to estimate differences in prevalence of low HDL-c and desirable TC. Results: The final study population was comprised of 380 efavirenz and 281 atazanavir initiators. Both atazanavir and efavirenz users had increases in serum HDL-c and decreases in TC/HDL ratio. In comparison to individuals initiating efavirenz, boosted atazanavir users on average had lower HDL-c (-4.12 mg/dl, p<0.001) and non HDL-c (-5.75 mg/dl, p<0.01), but similar declines in TC/HDL ratio. Conclusion: Both efavirenz and atazanavir-based regimens (boosted and unboosted) resulted in similar beneficial declines in the TC/HDL ratio.

Effectiveness of antiretroviral therapy and development of drug resistance in HIV-1 infected patients in Mombasa, Kenya

Kim Steegen — 2009-06-16T00:00:00Z

Access to antiretroviral therapy (ART) is increasing in resource-limited settings (RLS) and can successfully reduce HIV-related morbidity and mortality. However, virologic failure and development of viral drug resistance can result in reduced treatment options and disease progression. Additionally, transmission of resistant virus, and particularly multi-drug resistance, could become a public health concern. This study evaluated treatment success and development of ART drug resistance after short-term treatment among patients attending the Comprehensive HIV Care Centre (CCC) of Coast Province General Hospital, Mombasa, Kenya. One hundred and fifty HIV-infected individuals receiving ART were consecutively recruited to participate in the study. After determination of plasma viral load, patients with detectable viral load levels were subjected to genotypic drug resistance testing. At the time of sampling, 132 of the 150 participants were on ART for more than 6 months (median 21 months, IQR = 12–26). An efficient viral load reduction to below 50 copies/ml was observed in 113 (85.6%) of them. Of the 19 patients with a detectable viral load, sequencing of the protease (PR) and reverse transcriptase (RT) gene was successful in 16. Eleven (11) of these 16 patients were infected with a subtype A1 virus. Major PR mutations were absent, but mutations associated with drug resistance in RT were detected in 14 of the 16 patients (87.5%). High-level resistance against at least 2 drugs of the ART regimen was observed in 9/14 (64.3%). The 3TC mutation M184V and the NNRTI mutation K103N were most frequent but also the multi-drug resistance Q151M and the broad NRTI cross-resistance K65R were observed. The results of this study revealed a high rate of treatment success after short term ART in patients treated at a public provincial hospital in a RLS. Nevertheless, the observed high risk of accumulation of resistance mutations among patients failing treatment and the selection of multi-drug resistance mutations in some, remains of great concern for future treatment options and potential transmission to partners.

Comparison of brachial and carotid artery ultrasound for assessing extent of subclinical atherosclerosis in HIV: a prospective cohort study

Adefowope Odueyungbo — 2009-06-11T00:00:00Z

Background: Non-invasive surrogate measures which are valid and responsive to change are needed to study cardiovascular risks in HIV. We compared the construct validity of two noninvasive arterial measures: carotid intima medial thickness (IMT), which measures anatomic disease; and brachial flow-mediated vasodilation (FMD), a measure of endothelial dysfunction. Methods: A sample of 257 subjects aged 35 years or older, attending clinics in five Canadian centres, were prospectively recruited into a study of cardiovascular risk among HIV subjects. The relationship between baseline IMT or FMD and traditional vascular risk factors was studied using regression analysis. We analyzed the relationship between progression of IMT or FMD and risk factors using fixed-effects models. We adjusted for use of statin medication and CD4 count in both models. Results: Baseline IMT was significantly associated with age (p < 0.001), male gender (p = 0.034), current smoking status (p < 0.001), systolic blood pressure (p < 0.001) and total:HDL cholesterol ratio (p = 0.004), but not statin use (p = 0.904) and CD4 count (p = 0.929) . IMT progression was significantly associated with age (p < 0.001), male gender (p = 0.0051) and current smoking status (p = 0.011), but not statin use (p = 0.289) and CD4 count (p = 0.927). FMD progression was significantly associated with current statin use (p = 0.019), but not CD4 count (p = 0.84). Neither extent nor progression of FMD was significantly associated with any of the examined vascular risk factors. Conclusions: IMT correlates better than FMD with established cardiovascular risk factors in this cohort of HIV patients. Standardization of protocols for FMD and IMT will facilitate the comparison of results across studies.

Adrenal suppression due to an interaction between ritonavir and injected triamcinolone: a case report

Kathryn Dort — 2009-06-08T00:00:00Z

Two HIV-1 infected patients developed signs and symptoms consistent with adrenal suppression after being exposed to intra-articular triamcinolone acetate while also receiving ritonavir as part of their highly active antiretroviral therapy. Laboratory evaluation confirmed secondary adrenal suppression in both cases. Both patients recovered without the need for chronic replacement steroids. Adrenal suppression has been described as an adverse outcome in patients treated with fluticasone and concomitant ritonavir. In the reported cases, the adrenal suppression likely developed as a result of increased systemic concentrations of triamcinolone due to an inhibition of cytochrome p450 3A4 metabolism. Practitioners of HIV medicine should be aware of the potential negative interaction of injected triamcinolone and ritonavir.

An alternative methodology for the prediction of adherence to anti HIV treatment.

I Richard Thompson — 2009-06-01T00:00:00Z

Background: Successful treatment of HIV-positive patients is fundamental to controlling the progression to AIDS. Causes of treatment failure are either related to drug resistance and/or insufficient drug levels in the blood. Severe side effects, coupled with the intense nature of many regimens, can lead to treatment fatigue and consequently to periodic or permanent non-adherence. Although non-adherence is a recognised problem in HIV treatment, it is still poorly detected in both clinical practice and research and often based on unreliable information such as self-reports, or in a research setting, Medication Events Monitoring System caps or prescription refill rates. To meet the need for having objective information on adherence, we propose a method using viral load and HIV genome sequence data to identify non-adherence amongst patients.Presentation of the hypothesisWith non-adherence operationally defined as a sharp increase in viral load in the absence of mutation, it is hypothesised that periods of non-adherence can be identified retrospectively based on the observed relationship between changes in viral load and mutation.Testing the hypothesisSpikes in the viral load (VL) can be identified from time periods over which VL rises above the undetectable level to a point at which the VL decreases by a threshold amount. The presence of mutations can be established by comparing each sequence to a reference sequence and by comparing sequences in pairs taken sequentially in time, in order to identify changes within the sequences at or around 'treatment change events'. Observed spikes in VL measurements without mutation in the corresponding sequence data then serve as a proxy indicator of non-adherence.Implications of the hypothesisIt is envisaged that the validation of the hypothesised approach will serve as a first step on the road to clinical practice. The information inferred from clinical data on adherence would be a crucially important feature of treatment prediction tools provided for practitioners to aid daily practice. In addition, distinct characteristics of biological markers routinely used to assess the state of the disease may be identified in the adherent and non-adherent groups. This latter approach would directly help clinicians to differentiate between non-responding and non-adherent patients.

Fat distribution and longitudinal anthropometric changes in HIV-infected men with and without clinical evidence of lipodystrophy and HIV-uninfected controls: A substudy of the Multicenter AIDS Cohort Study

Todd Brown — 2009-05-13T00:00:00Z

Background: Fat abnormalities are common among HIV-infected persons, but few studies have compared regional body fat distribution, including visceral fat, in HIV-infected and HIV-uninfected persons and their subsequent trajectories in body composition over time. Methods: Between 1999 and 2002, 33 men with clinical evidence of lipodystrophy (LIPO+), 23 HIV-infected men without clinical evidence of lipodytrophy (LIPO-), and 33 HIV-uninfected men were recruited from the four sites of the Multicenter AIDS Cohort Study (MACS). Participants underwent dual-energy x-ray absorptiometry, quantitative computerized tomography of the abdomen and thigh, and circumference measurements of the waist, hip and thigh. Circumference measurements at each semi-annual MACS visit between recruitment and 2008 were used to compare average annual anthropometric changes in the 3 groups. Results: Body mass index (BMI) was lower in LIPO+ men than in the LIPO- men and the HIV- uninfected controls (BMI: 23.6 ± 0.4 vs 26.8 ± 1.5 vs 28.7 ± 0.9 kg/m2, respectively, p < 0.001). The average amount of visceral adipose tissue (VAT) was similar in all three groups (p = 0.26), but after adjustment for BMI, VAT was higher in the LIPO+ group (169 ± 10 cm2) compared to the LIPO- men (129 ± 12 cm2, p = 0.03) and the HIV-uninfected group (133 ± 11 cm2, p = 0.07). Subcutaneous adipose tissue (thigh, abdomen) and total extremity fat were less in the HIV-infected men (LIPO+ and LIPO-) than in the HIV-uninfected men. Over an average of 6 years of follow-up, waist circumference increased at a faster rate in LIPO+ group, compared to the LIPO- men (0.51 cm/year vs 0.08 cm/year, p = 0.02) and HIV-uninfected control men (0.21 cm/year, p = 0.06). The annual changes in hip and thigh circumferences were similar in all three groups Conclusion: Subcutaneous lipoatrophy was observed in HIV-infected patients, even those without clinical evidence of lipodystrophy, compared to age-matched HIV-uninfected men. Despite markedly lower BMI, HIV-infected men with lipodystrophy had a similar amount of VAT as HIV-uninfected men and tended to have more rapid increases in waist circumference over 6 years of follow-up. These longitudinal increases in waist circumference may contribute to the development of cardiovascular risk in HIV-infected patients with lipodystrophy.

Adherence to anti-retroviral therapy among HIV patients in Bangalore, India

M Cauldbeck — 2009-04-28T00:00:00Z

IntroductionHuman Immunodeficiency Virus (HIV) has an estimated prevalence of 0.9% in India (5.2 million). Anti-retroviral drugs (ARV) are the treatments of choice and non-adherence is an important factor in treatment failure and development of resistance, as well as being a powerful predictor of survival. This study assesses adherence to ARV in HIV positive patients in Bangalore, India, a country where only 10% of those who need therapy are receiving it. Methods: A cross-sectional anonymous questionnaire survey of 60 HIV antibody positive patients was carried out with patients attending HIV outpatient services at two centres: The Chest and Maternity Centre, Rajajinagar, and Wockhardt Hospital and Heart Institute, Bangalore. Consent was obtained. Translation was done by a translator and doctors where required. Data was analysed using SPSS statistical analysis. Results: A response rate of 88% (53/60) was achieved. The mean patient age was 39.98 years, with 50% aged 30–40, and 73.6% of participants being male. Mean family size was 4.8 (1–13). 21% lived less than 50 kms and 21% greater than 400 kms from clinic.60% reported they were fully adherent. Adherence was statistically significantly linked to regular follow-up attendance (70.5%, p = 0.002). No other results were statistically significant but trends were found. "100% adherence" trends were seen in older patients, male gender, those from larger families, those who had a previous AIDS defining illness, those taking fewer tablets, and without food restrictions. Commonest side-effects causing non-adherence were metabolic reasons (66%) and GI symptoms (50%). No trends were seen for education level, family income, distance travelled to clinic, time since diagnosis, or time on ART. Conclusion: Regular attendance for follow up was statistically significant for 100% lifetime adherence. Positive trends were seen in those in larger families, older, those who had AIDS defining illness, simple regimes, and without side-effects. Education, income, distance travelled and length of time diagnosed or treated had no effect on adherence.

Ankle-brachial index in HIV infection.

Julian Olalla — 2009-04-27T00:00:00Z

Prognosis for patients with the human immunodeficiency virus (HIV) has improved with the introduction of highly active antiretroviral therapy (HAART). Evidence over recent years suggests that the incidence of cardiovascular disease is increasing in HIV patients. The ankle-brachial index (ABI) is a cheap and easy test that has been validated in the general population. Abnormal ABI values are associated with increased cardiovascular mortality. To date, six series of ABI values in persons with HIV have been published, but none was a prospective study. No agreement exists concerning the risk factors for an abnormal ABI, though its prevalence is clearly higher in these patients than in the general population. Whether this higher prevalence of an abnormal ABI is associated with a higher incidence of vascular events remains to be determined.