Current HIV Research - Volume 8, Issue 3, 2010

Objective: The primary objective of this study was to investigate the impact of HCV infection and of HCV genotypes on immune restoration in HIV-infected patients on a successful HAART regimen. Methods: Patients from the MASTER Study were included in this current longitudinal study if they met the following criteria: being on any successful HAART, and availability of CD4+ cell count and HIV RNA level before starting the suppressive HAART and 12 months after suppressive therapy, and availability of HCV antibodies. The primary endpoints of the study were defined as achieving a difference above 100 cell/mmc between CD4+ at baseline and at time of HIV RNA suppression while on therapy (Δ CD4+early), or 12 month after a suppressive therapy (Δ CD4+late). Results: 844 HIV-positive patients were included in the analysis: 673 were HCV-negative and 171 were HCV-positive [92 (53.8%) subjects had HCV genotype 1; 58 (33.9%), genotype 3; 21 (12.3%), genotype 4]. Plasma HIV RNA (both baseline as highest value), nadir CD4+, being naive, time to reach undetectable plasma HIV RNA, treatment with PI vs NNRTI being associated with an early immunological recovery; the occurrence of previous AIDS event, a history of injection drug use, and HCV infection being associated with failure to achieve an early immunological recovery. Variables associated with Δ CD4+late immune recovery were baseline CD4+ value, plasma HIV RNA (both baseline as highest value), being naive and time to reach undetectable plasma HIV RNA. HCV infection per se was not associated with a worse probability to reach late immunologic response, although among HCV infected patients, having a genotype 3 was associated with a worse immune recovery. At multivariable analysis, factors that remained associated with failure to achieve an early immunological response were being HCV infected and history of injection drug use, while those associated with a failure to achieve a late immunological response were infection with HCV genotype 3 and older age. Conclusions: A blunted early immune recovery was observed in HCV infected patients, compared with HCV negative subjects, while late immune recovery was not different among HCV infected as a whole and not infected subjects; only the subgroup of subjects infected with genotype 3 showed an impaired late immune recovery.

Objective: The primary objective of this study was to estimate etravirine activity in a cohort of patients infected with non-B subtype HIV-1 and failing nevirapine-based therapy. Materials and Methods: Genotypic resistance testing was performed if viral load was ® 1,000 copies/ml after receiving at least six months of therapy. Suboptimal response to etravirine was predicted by a score ® 2.5 on the Tibotec weighting schema, ® 4 in the Monogram schema, or classification as high to low-level resistant by a modification of the Stanford HIVdb algorithm (Version 5.1.2). Bivariate and multivariate analyses were conducted to determine the risk factors for suboptimal etravirine activity. Results: The patients (n=91) were receiving nevirapine and lamivudine plus stavudine (57.1%) or zidovudine (42.9%). Median duration of nevirapine exposure was 53 weeks (IQR 46-101 weeks). The most common etravirine resistance associated mutations were Y181C (42.9%), G190A (25.3%), H221Y (19.8%), A98G (18.7%), K101E (16.5%), and V90I (12.1%). Suboptimal etravirine activity was predicted in 47.3 to 56.0%. There were disparities in mutations listed in Tibotec vs Monogram Schemas. Predicted suboptimal activity was not associated with nucleoside reverse transcriptase inhibitor (NRTI) used, gender, pretreatment or current CD4 cell count or viral load, subtype or NRTI mutations. Conclusion: Etravirine has compromised activity in approximately half of the patients failing nevirapine-based first-line treatment in this cohort, which supports guidelines that caution against using it with NRTIs alone in such patients.

Efficient expression of HIV-1 structural gene involves regulation by viral Rev and Rev-responsive elements (RRE). Messenger RNAs of wild-type HIV-1 structural genes are either retained in the nucleus or degraded rapidly in the absence of Rev/RRE; therefore little protein can be expressed. Modifying HIV-1 genes is an excellent approach to circumvent this problem, but it is a laborious and costly process. Using certain vectors to deliver wild-type genes may be a promising approach. In this study, the wild-type and modified gag genes, derived from Chinese HIV-1 isolates, were separately constructed in both plasmid DNA and recombinant Sendai virus vectors (rSeV). The expression and immunogenicity of the wild-type and modified gag genes were compared. The results showed that efficient expression of the modified gag gene could be achieved by transfection with DNA and infection with rSeV, but the efficient expression of wild-type gag could only be achieved by rSeV. In addition, the rSeV expressing wild-type gag elicited similar Gagspecific immune responses with modified gag in both SeV/SeV and DNA-prime/rSeV-boost schemes. However, SeV/SeV failed to produce Gag-specific responses as robust as DNA/rSeV. Then the SeV-specific humoral and cellular immune responses were evaluated just before the second rSeV vaccine immunization. It was found that anti-SeV neutralizing antibody was very low but the SeV-specific cellular response was strong. Efficient expression of wild-type HIV-1 structural genes may make the SeV vector a useful tool for the HIV-1 vaccine research, but the strong SeV-specific cellular immune responses may impair the efficacy of SeV-SeV vaccination scheme.

Objectives: We tested the association between specific values and beliefs, cultural representations of HIV/AIDS and high-risk sexual and drug-use behaviours in the Former Soviet Republic of Georgia. Methods: We questioned 2880 adolescents aged 14-17 in Georgia using a three-stage stratified probability sample. Respondents were from nine regions sampled across the country. Participants completed an inventory measuring demographic variables and openness to change values, fatalism, specific societal beliefs, sexual contact, drug taking and condom use. Results: Sexual intercourse was reported by 40% of males, 3% of females; drug injection by 4% males, 1% of females. Those living in urban locations were more likely to report having had sex, have used condoms regularly, and tried noninjection drugs. In multivariate logistic analyses, openness to change values was associated with having had sex, and fatalistic beliefs with having had sex, irregular condom use and drug injection. Particular beliefs (e.g. that “mainly gay people get AIDS”) were associated with irregular condom use and a greater likelihood of drug injection. Conclusions: Location and specific values and beliefs are important risk factors for increased sexual risk-taking and drug use amongst adolescents in Georgia..

Background: Non-acquired immune-deficiency syndrome (AIDS) defining malignancies (especially lung cancer) and bacterial infections as well as cardiovascular diseases now account for almost one third of deaths and morbid events in treated patients infected by the Human Immunodeficiency Virus (HIV). Tobacco smoking is a major modifiable risk factor of these emergent conditions and almost half of these patients are regular smokers in resource-rich countries. Objective: To estimate the effect of HIV infection characteristics on smoking cessation attempts among HIV-infected smokers. Methods: All smokers of the ANRS CO3 Aquitaine Cohort with at least two visits between 2000 and 2005 were included in this analysis. The probability of smoking cessation attempts was estimated using survival analyses for recurrent events (frailty model). Covariates were CD4 cell count, gender, age, HIV transmission categories, duration since HIV-diagnosis, AIDS stage, antiretroviral therapy, and cardiovascular history. Results: Among 2223 smokers, 743 attempted to quit smoking at least once. The incidence of smoking cessation attempt was lower among patients infected through injection drug use (IDU) and was higher among patients aged 50 or older (HR=1.4), those with a known duration of HIV infection ®15 years (HR=1.5), and those who had already tried to quit smoking once (HR=4.2) or more (HR=5.8). Discussion: Traditional characteristics associated with smoking cessation attempts are the most important to explain smoking cessation attempts in HIV-infected patients.These results indicate that strategies successfully implemented in other populations should be reinforced to fit the needs of HIV-infected patients.

Background: Although FOLFOX4 is considered the standard chemotherapy regimen for colorectal cancer (CRC), few data are available on its results in human immunodeficiency (HIV)-related CRC. The results were analyzed to evaluate feasibility and activity of FOLFOX4 plus highly active antiretroviral therapy (HAART) in metastatic CRC (mCRC) HIV-seropositive patients. Patients and Methods: From January 2002 to March 2007, 24 patients were selected among the CRC HIV-seropositive patients treated with FOLFOX4 and concomitant HAART within the Italian Cooperative Group on AIDS and Tumors (GICAT). Results: Four median cycles of chemotherapy were administered; the most common severe toxicity was neutropenia (37.5%). An overall response rate of 50% was observed; 4.2% of patients achieved complete response and 45.8% partial response. No opportunistic infections occurred during or immediately after chemotherapy. The medi+ count was 380 (range 220-570) at diagnosis. Conclusions: To our knowledge, this is the largest study describing activity and tolerability of FOLFOX4 and HAART, in this setting. FOLFOX4 plus concomitant HAART resulted feasible and active also in HIV-seropositive patients. Moreover, the concomitant use of HAART did not seem to increase the FOLFOX4 toxicity. This study suggests the good tolerability of the FOLFOX4, making it a reasonable option for combination with HAART.

Pediatric HIV is scarce in developed countries; 90% of pediatric HIV patients are in developing countries. In contrast, children represent 15% of the new infections in poor countries. Approximately 90% of the HIV-positive children do not have access to antiretrovirals (ARVs). Without treatment, 50% of the patients die before the 2 years of age. Efavirenz (EFV, aqueous solubility ~4 μg/mL, 40-45% bioavailability), a non-nucleoside reverse transcriptase inhibitor (NNRTI), is a first-choice pediatric AμV. To assure therapeutic plasma concentrations, the low oral bioavailability demands the administration of relatively high EFV doses. Aqueous EFV irritates the oral mucosa, causing a Burning Mouth Syndrome (BMS). A triglyceride-based liquid formulation of EFV (30 mg/mL) is not commercially available worldwide, making the appropiate dose adjustment and the swallowing difficult. More importantly, clinical trials indicated that the oral bioavailability of this oily solution is lower than that of the solid one. Moreover, a relatively high inter-subject variability has been found. The present work reports the development and full characterization of a concentrated (20 mg/mL, 2%) and taste-masked aqueous formulation of EFV for a more appropriate management of the pediatric anti-HIV therapy. Formulations displayed high physicochemical stability over time under regular storage conditions. Release assays in vitro showed a burst effect (2 h) and zero-order kinetics later on (between 2 and 24 h), compatible with the oral administration route and release. Finally, taste tests performed by adult healthy volunteers indicated that the unique combination of flavors and sweeteners employed (i) reduced the intensity of the BMS and (ii) shortened its duration significantly. Overall results indicate that the cost-effective and scalable nanotechnological strategy proposed could enable the more covenient and compliant administration of lower EFV doses. Due to a better pharmacokinetic profile, this would result in similar plasma levels than higher doses administered in solid or triglyceridesoluble form. In this context, some reduction of the treatment cost can be envisioned. This could improve the access of less affluent pediatric patients to medication in poor countries.

Background: Peripheral neuropathy is the dose-limiting toxicity of stavudine and didanosine (nucleoside analogs used in HIV treatment) and is attributed to mitochondrial toxicity from these drugs. Acetyl L-carnitine (ALC) and co-enzyme Q10 are proposed as neuropathy treatments, but evidence to support these is limited. Methods: We examined ALC and a water-soluble formulation of co-enzyme Q10 (HQO™) for the prevention of d4T and ddI neurotoxicity using cultured fetal rat DRG as an in vitro model. Results: DdI (33μM) and d4T (50μM) caused clear toxicity (impaired neurite growth) by day 8 of DRG culture. HQO™ at concentrations 1-100μM completely prevented the toxicity of 33μM ddI in vitro and ALC at concentrations 1-100 μM substantially (but incompletely) prevented ddI toxicity in this model. In contrast, ALC was ineffective at all concentrations tested for preventing the toxicity of 50μM d4T. HQO™ showed dose-dependent efficacy for preventing d4T toxicity. HQO™ (1μM) partially prevented d4T toxicity while 10 and 100μM HQO™ completely prevented d4T toxicity in this model. Conclusions: We find HQO™ is superior to ALC for preventing the neurotoxicity of d4T (the HIV treatment most associated with neuropathy) and ddI in vitro. Further study is needed to clarify any clinical role for co-enzyme Q10 coadministration with d4T and ddI and to assess whether this compound may have a role in treating established cases of neuropathy.

Human immunodeficiency virus type 1 (HIV-1) and several simian immunodeficiency viruses (SIV) encode for a transmembrane protein known as Vpu (viral protein U). While one of the smallest of the HIV-1 proteins, it has two important functions within virus-infected cells. The first of these functions is the down-regulation of the CD4 receptor to prevent its interaction with the HIV-1 envelope glycoprotein. Vpu interacts with the CD4 receptor in the rough endoplasmic reticulum (RER), resulting in its re-translocation across the RER and subsequent degradation via the proteasomal pathway. The second major function of the Vpu protein is to facilitate release of virus from infected cells. Previous studies have shown that virus release is cell type specific, suggesting that certain cells may express a restriction factor that inhibits virus release in the absence of Vpu. Recently, bone marrow stromal antigen 2 (BST- 2/HM1.24/CD317/tetherin) has been identified as this factor. This review will focus on new findings within the last four years on the role of Vpu in CD4 down-regulation and the restriction of virus release from cells. We will relate these findings to virus pathogenesis and propose questions regarding BST-2 as a restriction factor.

Introduction: Tuberculosis (TB) is a pandemic infectious disease especially frequent in HIV-infected patients. Toll-like receptor (TLR) 4 has been described to play a main role in the innate immunity against TB. In fact, single nucleotide polymorphisms (SNPs) in TLRs may influence AIDS disease progression. The association between two particular SNPs in human TLR4 (Asp299Gly and Thr399Ile) and active TB has been studied in non-HIV Africans with contradictory results. However, studies focusing on the effect of these TLR4 SNPs in active TB within a Caucasian HIV population are lacking. Objectives: To analyze the association between TLR4 Asp299Gly and Thr399Ile SNPs and active TB, in Caucasian Mediterranean HIV-infected individuals. Methods: 468 HIV-infected patients were analyzed. TLR4 genotyping was performed by real-time PCR and melting curve technology. Results: TB was diagnosed in 59 (12,6%) patients. In a bivariate analysis several variables resulted significantly associated with active TB; intravenous drugs use (OR= 2.2; 95% CI [1.2-3.8]), hepatitis C virus (HCV) co-infection (OR= 3.4; 95% CI [1.6-7.1]), CD4 count (p<0.001), HIV viral load (p=0.003), latent TB prophylaxis (OR= 0.3; 95% CI [0.1- 0.5]), and TLR4 Asp299Gly (OR= 2.0; 95% CI [1.1-4.2]). No statistical association was found for the TLR4 Thr399Ile. After a multivariate analysis, HCV co-infection (OR= 3.8; 95% CI [2.2-6.5]), baseline CD4 count (OR= 0.996; 95% CI [0.994-0.998]), TLR4 Asp299Gly (OR= 2.57; 95% CI [1.18-5.61]) were independently associated with active TB and inversely with latent TB prophylaxis (OR= 0.24; 95% CI [0.01-0.60]). Conclusions: We describe an independent association between TLR4 Asp299Gly SNP and active TB in Caucasian Mediterranean HIV-infected patients.

In Malaysia, co-circulation of CRF01_AE and subtype B has resulted in the emergence of the second generation derivative; CRF33_01B in approximately 20% of its HIV-1 infected individuals. Our objective was to identify possible biological advantages that CRF33_01B possesses over its progenitors. Biological and molecular comparisons of CRF33_01B against its parental subtypes clearly show that CRF33_01B replicated better in activated whole peripheral blood mononuclear cells (PBMCs) and CD4+ T-lymphocytes, but not monocyte-derived macrophages (MDMs). Also, its acquired fitness was greater than CRF01_AE but not subtype B. Moreover, CRF33_01B has higher rate of apoptotic cell death and syncytia induction compared to subtype B. These adaptive and survival abilities could have been acquired by CRF33_01B due to the incorporation of subtype B fragments into the gag-RT region of its full-length genome. Our studies confirm the previously held belief that HIV-1 strains may harbor enhanced biological fitness upon recombination. We therefore estimate a possible gradual replacement of the current predominance of CRF01_AE, as well as wider dissemination of CRF33_01B, together with the identification of other new CRF01_AE/B inter-subtype recombinants in Malaysia.