Pharmacokinetics and pharmacodynamics of antiretrovirals in the central nervous system

The central nervous system is a potential reservoir and possible origin of drug resistance in hepatitis B infection

Background

The significance of hepatitis B virus (HBV) in cerebrospinal fluid (CSF) is unclear.

Methods

Synchronous serum and CSF samples were collected from 13 patients. HBV DNA, full-length genome, quasispecies, phylogenetic tree, compartmentalization and mutation of the reverse transcriptase (RT) region were performed based on PCR and sequencing methods.

Results

HBV DNA was detected in the CSF of 3 antiviral-naïve individuals and 1 individual after successful antiviral therapy. Complete full-length HBV genomes were isolated from the CSF of 5 individuals, including 2 with undetectable serum HBV DNA. Ten individuals exhibited distinct CSF-serum quasispecies, 8 harbored independent CSF-serum genetic compartmentalization and phylogenetic trees, and 5 lamivudine/entecavir-associated resistance mutations only in the CSF. The frequencies of rtL180M and rtM204I/V mutations in both serum and CSF were higher in HIV-HBV-coinfected individuals than in the HBV-monoinfected ones (serum: rtL180M: 3.9% vs. 0, P = 0.004; rtM204I/V: 21.3% vs. 0, P < 0.001; CSF: rtL180M: 7.6% vs. 0, P = 0.026; rtM204I/V 7.6% vs. 1.6%, P = 0.097).

Conclusion

CSF is a potential HBV reservoir, and HBV in CSF harbors distinct evolution and mutation characteristics from those in serum. HIV infection increases the possibility of HBV rtL180M and rtM204I/V mutations in both serum and CSF.

Association of depression and suicidal behaviour reporting with HIV integrase inhibitors: a global pharmacovigilance study

OBJECTIVES

Concerns have been raised regarding neuropsychiatric adverse drug reactions of integrase inhibitors (INSTIs) in patients living with HIV. The aim of this study was to assess the risk of depression and suicidality reporting with INSTIs based on a global pharmacovigilance database.

METHODS

Depression and suicidality cases in patients treated with INSTIs were identified within the WHO global database of individual case safety reports, VigiBase. Risk of depression and suicidality reporting with INSTIs compared with other ART was assessed using disproportionality analyses (case/non-case statistical approach).

RESULTS

Of 19 991 410 reports over the study period, 124 184 reports concerned patients exposed to ART, including 22 661 patients exposed to an INSTI. Among patients treated with an INSTI, 547 cases of depression and 357 cases of suicidality were identified. Disproportionality analyses showed that depression [reporting OR (ROR) 3.6; 95% CI: 3.2-4.0] and suicidality (ROR 4.7; 95% CI: 4.1-5.4) were more reported with the use of INSTIs compared with other ART. Amongst INSTIs, depression reporting was significantly greater for bictegravir and dolutegravir, whereas suicidality reporting was significantly greater for dolutegravir only.

CONCLUSIONS

Our findings suggest that depression and suicidality are adverse drug reactions of all INSTI agents, especially dolutegravir, which may occur within the first months of therapy.

Persistent HIV transcription and variable antiretroviral drug penetration in lymph nodes during plasma viral suppression

OBJECTIVE

The ability of antiretroviral drugs to penetrate and suppress viral replication in tissue reservoir sites is critical for HIV remission. We evaluated antiretroviral concentrations in lymph nodes and their impact on HIV transcription.

METHODS

Participants of the RV254/SEARCH010 Acute HIV Infection Cohort in Thailand were enrolled. Group 1 (n  = 6) initiated and continued antiretrovirals with two nucleoside reverse transcriptase inhibitors (NRTIs), dolutegravir (DTG) and mar- aviroc (MVC). Group 2 (n = 12) initiated antiretrovirals with two NRTIs as well as efavirenz and were switched to two NRTIs as well as DTG. Antiretroviral concentrations were measured by mass spectroscopy. HIV RNA+ and DNA+ cells were measured by in-situ hybridization.

RESULTS

All participants were MSM. At lymph node biopsy, all had plasma HIV RNA less than 20 copies/ml. Group 2 had longer durations of antiretroviral and DTG use (medians of 135 and 63 weeks, respectively) compared with Group 1 (median 44 weeks for both). TFV-DP, 3TC-TP, DTG and MVC were quantifiable in all lymph node samples from participants receiving those drugs versus carbovir-triphosphate (CBV-TP) in four out of 14. Median ratios of lymph node to peripheral blood concentrations were DTG, 0.014; MVC, 6.9; CBV-TP, 0.38; 3TC-TP, 0.32; and TFV-DP, 3.78. Median inhibitory quotients [ratios of lymph node concentrations to in-vitro inhibitory levels (IC50-or-90)] were DTG, 0.8; MVC, 38.8; CBV-TP, 0.5; 3TC- TP, 4.1; and TFV-DP, 1.8. Ongoing viral transcription was detected in lymph node of all participants. Median lymph node RNA+ cells were 71 350 versus 99 750 cells/g for Groups 1 and 2, respectively (P = 0.111).

CONCLUSION

MVC has enhanced lymph node penetration and thereby may contribute to more complete viral suppression in the lymph node.

Alzheimer Dementia in People Living With HIV

Objective

Given the aging of people living with HIV (PLWH) and the high prevalence of HIV-associated neurocognitive disorders, we aimed at describing the clinical, instrumental, and CSF features of PLWH diagnosed with Alzheimer dementia (AD).

Methods

The databases of 3 large Italian outpatient clinics taking care of more than 9,000 PLWH were searched for the diagnosis of AD. After obtaining patients' or their next of kin's consent for publication, anonymous data were collected in an excel spreadsheet and described. Routinely collected CSF biomarkers and radiologic imaging results were recorded whether available.

Results

Four patients were included in this case series who were diagnosed with AD aged between 60 and 74 years. All participants were on highly active antiretroviral therapy and showed nondetectable serum HIV RNA. Memory impairment was the most prominent cognitive feature. The diagnosis was obtained considering the exclusion of other potential causes, MRI and fluorodeoxyglucose-PET features, and, in (in 2/4), CSF AD biomarkers levels. In 1 patient, longitudinal CSF tau/p-tau increased, and beta-amyloid_1-42 decreased over time despite antiretroviral therapy containing nucleotide reverse transcriptase inhibitors.

Conclusions

In older PLWH cognitive symptoms may represent the onset of AD: a multidisciplinary team may be needed for reaching a likely in vivo diagnosis.

CD4+ T cell-mimicking nanoparticles encapsulating DIABLO/SMAC mimetics broadly neutralize HIV-1 and selectively kill HIV-1-infected cells

HIV-1 is a major global health challenge. The development of an effective vaccine and a therapeutic cure are top priorities. The creation of vaccines that focus an antibody response toward a particular epitope of a protein has shown promise, but the genetic diversity of HIV-1 stymies this progress. Therapeutic strategies that provide effective and broad‐spectrum neutralization against HIV-1 infection are highly desirable.

Methods: We investigated the potential of nanoengineered CD4+ T cell membrane-coated nanoparticles (TNP) encapsulating the DIABLO/SMAC mimetics LCL-161 or AT-406 (also known as SM-406 or Debio 1143) to both neutralize HIV-1 and selectively kill HIV-1-infected resting CD4+ T cells and macrophages.

Results: DIABLO/SMAC mimetic-loaded TNP displayed outstanding neutralizing breadth and potency, and selectively kill HIV-1-infected cells via autophagy-dependent apoptosis while having no drug-induced off-target or cytotoxic effects on bystander cells. Genetic inhibition of early stages of autophagy abolishes this effect.

Conclusion: DIABLO/SMAC mimetic loaded TNP have the potential to be used as therapeutic agents to neutralize cell-free HIV-1 and to kill specifically HIV-1-infected cells as part of an HIV-1 cure strategy.

Intramuscular and subcutaneous administration of antiretroviral drugs, compared with oral, enhances delivery to lymphoid tissues in BALB/c mice

BACKGROUND

Multiple tissue reservoirs are established soon after HIV infection, and some tissues may also be pharmacological sanctuaries. Parenteral administration of antiretroviral (ARV) drugs for treatment and prevention of HIV infection is an active area of drug development. The influence of route of administration on ARV tissue pharmacokinetics is not known.

OBJECTIVES

To investigate ARV pharmacokinetics in lymphatic and select non-lymphatic tissues (e.g. brain and testes) after intramuscular and subcutaneous administration compared with oral in BALB/c mice.

METHODS

Tissue concentrations of cobicistat, efavirenz, elvitegravir, maraviroc, rilpivirine, tenofovir alafenamide and tenofovir disoproxil fumarate were determined. The tissue penetration ratio (TPR) was the primary measure for comparison; a change in TPR arises from factors affecting tissue distribution controlling for changes in systemic bioavailability.

RESULTS

Intramuscular and subcutaneous delivery increased TPRs in the lymph node and spleen for 27 of 28 (96%) drug administration events. Decreased TPRs, however, were found in some tissues such as the brain and testes.

CONCLUSIONS

These results demonstrate a change in route of drug administration from oral to intramuscular or subcutaneous can change tissue uptake. This has implications for HIV pharmacotherapy. For example, HIV persists in lymphoid tissues despite long-term oral ARV therapy, and low ARV concentrations have been found in lymphoid tissues. The improved ARV lymphatic tissue bioavailability with intramuscular and subcutaneous administration allows future studies to investigate these routes of drug administration as a therapeutic manoeuvre to limit viral persistence and eliminate viral sanctuaries in the lymphatic tissues, which is a prerequisite for eradication of HIV.

Antiretroviral Drugs Impact Autophagy with Toxic Outcomes

Antiretroviral drugs have dramatically improved the morbidity and mortality of people living with HIV (PLWH). While current antiretroviral therapy (ART) regimens are generally well-tolerated, risks for side effects and toxicity remain as PLWH must take life-long medications. Antiretroviral drugs impact autophagy, an intracellular proteolytic process that eliminates debris and foreign material, provides nutrients for metabolism, and performs quality control to maintain cell homeostasis. Toxicity and adverse events associated with antiretrovirals may be due, in part, to their impacts on autophagy. A more complete understanding of the effects on autophagy is essential for developing antiretroviral drugs with decreased off target effects, meaning those unrelated to viral suppression, to minimize toxicity for PLWH. This review summarizes the findings and highlights the gaps in our knowledge of the impacts of antiretroviral drugs on autophagy.

Pharmacology of HIV Cure: Site of Action

Despite significant advances in HIV treatment over the past 30 years, critical barriers to an HIV cure persist. The HIV reservoir, defined at both the cellular and anatomical level, constitutes the main barrier to cure. While the mechanisms underlying the reservoir are not yet well understood, one theory to explain persistence at the anatomical level is that subtherapeutic exposure to antiretroviral therapy (ART) within certain tissue compartments permits ongoing replication. Characterizing ART pharmacology throughout the body is important in the context of these potential pharmacologic sanctuaries and for maximizing the probability of success with forthcoming cure strategies that rely on latency reversal and require ART to prevent reseeding the reservoir. In this review, we provide a comprehensive overview of ART and latency reversal agent distribution at the site of action for HIV cure (i.e., anatomical sites commonly associated with HIV persistence, such as lymphoid organs and the central nervous system). We also discuss methodologic approaches that provide insight into HIV cure pharmacology, including experimental design and advances within the computational, pharmaceutical, and analytical chemistry fields. The information discussed in this review will assist in streamlining the development of investigational cure strategies by providing a roadmap to ensure therapeutic exposure within the site of action for HIV cure.

Triumeq Increases Excitability of Pyramidal Neurons in the Medial Prefrontal Cortex by Facilitating Voltage-Gated Ca2+ Channel Function

Combination antiretroviral therapy (cART) suppresses HIV-1 replication, improves immune function, and prolongs the life of people living with HIV (PLWH). However, cART also induces neurotoxicity that could complicate HIV-induced neurodegeneration while reduce its therapeutic efficacy in treating HIV/AIDS. Triumeq is a first-line cART regimen, which is co-formulated by three antiretroviral drugs (ARVs), lamivudine (3TC), abcavir (ABC), and dolutegravir (DTG). Little is known about potential side effects of ARVs on the brain (including those co-formulating Triumeq), and their mechanisms impacting neuronal activity. We assessed acute (in vitro) and chronic (in vivo) effects of Triumeq and co-formulating ARVs on pyramidal neurons in rat brain slices containing the medial prefrontal cortex (mPFC) using patch-clamp recording approaches. We found that acute Triumeq or 3TC in vitro significantly increased firing of mPFC neurons in a concentration- and time-dependent manner. This neuronal hyperactivity was associated with enhanced Ca2+ influx through voltage-gated Ca2+ channels (VGCCs). Additionally, chronic treatment with Triumeq in vivo for 4 weeks (4 wks) also significantly increased firing and Ca2+ influx via VGCCs in mPFC neurons, which was not shown after 2 wks treatment. Such mPFC neuronal hyperexcitability was not found after 4 weeks treatments of individual ARVs. Further, chronic Triumeq exposure in vivo significantly enhanced mRNA expression of low voltage-activated (LVA) L-type Ca2+ channels (Cav1.3 L-channels), while changes in high voltage-activated (HVA) Cav1.2 L-channels were not observed. Collectively, these novel findings demonstrate that chronic cART induces hyperexcitability of mPFC pyramidal neurons by abnormally promoting VGCC overactivation/overexpression of VGCCs (including, but may not limited to, LVA-Cav1.3 L-channels), which could complicate HIV-induced neurotoxicity, and ultimately may contribute to HIV-associated neurocognitive disorders (HAND) in PLWH. Determining additional target(s) of cART in mPFC pyramidal neurons may help to improve the therapeutic strategies by minimizing the side effects of cART for treating HIV/AIDS.

Dual antiretroviral therapies are effective and safe regimens in the central nervous system of neurologically symptomatic people living with HIV

OBJECTIVE

Aim of this study was to compare cerebrospinal fluid (CSF) virological control, biomarkers and neurocognition of neurologically symptomatic patients on dual antiretroviral therapies (dual therapy) vs. 2 nucleoside reverse transcriptase inhibitors-based three-drug regimens (triple therapy).

DESIGN

Retrospective monocentric cross-sectional study.

METHODS

We analysed data from people living with HIV undergoing lumbar puncture for clinical/research reasons with plasma HIV-RNA less than 200 copies/ml and neurological/neurocognitive symptoms without significant contributing comorbidities. We measured CSF HIV-RNA, inflammation, blood-brain barrier integrity, neuronal damage and astrocytosis biomarkers (five biomarkers by ELISA and five indices by immunoturbidimetry) and recorded the neurocognitive performance (14 tests). CSF escape was defined as any case of CSF HIV-RNA 0.5 Log10 higher than viraemia or any case of detectable CSF HIV-RNA coupled with undetectable viraemia.

RESULTS

A total of 78 patients on triple therapy and 19 on dual therapy were included. Overall, 75.3% male, median age 51 years (46-58), current CD4 count 545 cells/μl (349-735), time on current regimens 18 months (8-29), but length of plasma suppression 32 months (14-94). The two groups did not differ in terms of HIV-associated neurological diagnoses, demographic and viro-immunological features. Undetectable CSF HIV-RNA (73.7% in dual therapy vs. 78.2% in triple therapy, p.67) and CSF escape (21.1% in dual therapy vs. 19.2% in triple therapy, p.86) did not differ. No difference was observed in depression, anxiety, neurocognition (in 63 participants) nor in any tested biomarker.

CONCLUSION

In people living with HIV with neurological/neurocognitive symptoms, peripherally effective dual therapy can show CSF virosuppression, inflammation, neuronal and astrocyte integrity and neurocognition comparable to triple therapy.

Antiretroviral drug concentrations in brain tissue of adult decedents

OBJECTIVE

Determine concentrations of antiretroviral therapy (ART) drugs in the human brain.

DESIGN

Cohort study of persons with HIV who consented to antemortem assessment and postmortem autopsy.

METHODS

Eleven persons with HIV who were taking ART at the time of death and had detectable concentrations of at least one ART drug in intracardiac aspirate at autopsy were evaluated. Autopsies were performed within 24 h of death and brain tissue was stored at -80 °C. Concentrations of 11 ART drugs were measured in three brain regions (globus pallidus, cortical gray matter, white matter) by HPLC tandem mass spectrometry with a lower limit of quantification of 25 ng/ml.

RESULTS

Participants were mostly men (82%) with a mean age of 40.4 years. Drug concentrations in brain tissue were highly variable and exceeded published concentrations in cerebrospinal fluid for several drugs, including for tenofovir, efavirenz, and lopinavir. Drug concentrations correlated most strongly between cortical gray matter and globus pallidus (rho = 0.70) but less well between globus pallidus and white matter (rho = 0.43). Combining all drugs and brain regions (n = 89), higher drug concentrations in brain were associated with longer estimated duration of HIV infection (P = 0.015), lower HIV RNA in plasma (P = 0.0001), lower nadir CD4 T-cell count (P = 0.053), and worse neurocognitive performance (P = 0.017).

CONCLUSION

This is the first analysis of ART drug concentrations in human brain tissue. Concentrations of several drugs in this analysis were similar to published concentrations in cerebrospinal fluid but others exceeded published concentrations. The association between higher drug concentrations in the brain and worse neurocognitive performance may indicate ART neurotoxicity.

Zidovudine and lamivudine reach higher concentrations in ventricular than in lumbar human cerebrospinal fluid

OBJECTIVE

For the treatment of HIV-1-related brain disease and for the prevention of the brain becoming a viral reservoir, it is important that antiretroviral agents reach sufficient concentrations in the CNS. To date, human brain pharmacokinetic data are solely derived from lumbar cerebrospinal fluid (CSF) and mostly originate from single samples.

DESIGN

We determined concentrations of antiretroviral drugs in serial samples of ventricular CSF and compared these to the concentrations in serum and lumbar CSF of these patients.

METHODS

Two treatment-naïve HIV-1-infected patients received external ventricular drainage for obstructive hydrocephalus. Starting with a combination antiretroviral regimen (cART), ventricular CSF, and subsequently lumbar CSF, with parallel serum, was frequently collected. Drug concentrations were determined and CSF-to-serum ratios were calculated.

RESULTS

High concentrations, resulting in high CSF-to-serum ratios, were found in the ventricular CSF of the three substances zidovudine, lamivudine and indinavir, whereas this was not observed for stavudine, ritonavir, saquinavir and efavirenz. Concentrations of zidovudine and lamivudine were up to four times greater in CSF from the ventricles than in lumbar CSF of the same patient. The zidovudine concentrations in the ventricular CSF exceeded serum concentrations by a factor of 1.4.

CONCLUSION

Unexpectedly high concentrations of some antiretrovirals in the ventricular CSF, the site close to the brain parenchyma where HIV is located, should be considered when the cART regimen is aiming at CNS viral replication.

Pharmacologic approaches to HIV-associated neurocognitive disorders

Antiretroviral therapy in people living with HIV can achieve potent, long-term suppression of HIV plasma viremia and has increased life expectancy. The central nervous system is infected early after virus acquisition and remains a reservoir for HIV. HIV-associated neurocognitive disorders (HAND) are an end-organ manifestation of HIV infection. The need to address neurological complications caused by HAND is significant as approximately 50% of people living with HIV on suppressive antiretroviral therapy are estimated to have some form of HAND. This review discusses the pathophysiology of HAND, CSF/CNS penetration and clinical pharmacology of antiretrovirals including pharmacokinetic/pharmacodynamic relationships, the persistence of HIV in the brain, and future therapeutic approaches to preserve and improve sustained viral suppression in the brain.

Novel dual HIV maintenance therapy with nevirapine plus lamivudine retain viral suppression through 144 weeks-A proof-of-concept study

OBJECTIVES

The aim of this proof-of-concept study is to test feasibility and efficacy of NVP plus Lamivudine (3TC) as novel simplified HIV maintenance dual therapy (DT) strategy.

METHODS

Patients under combined antiretroviral treatment (cART) with fully suppressed HIV plasma viral load (pVL) >24 months-whereof >6 months on an NVP- containing regimen-were switched to oral NVP plus 3TC for 24 weeks. Patients could then decide whether to continue DT or return to the previous cART. HIV pVL was monitored monthly until week 144. The primary outcome was confirmed viral failure (RNA >100 copies/ml). Low-level detection of HIV-RNA in plasma was compared in each patient with pre-study viral load measurements.

RESULTS

Twenty patients were included, switched to DT and all completed week 24. One patient decided thereafter to discontinue study participation for personal reasons. After a total of 144 observation weeks, none of the patients failed. The frequency of low- level HIV-RNA detection was not different from the period before randomization.

CONCLUSIONS

Our findings are surprising but given the nature of a proof-of-concept study, the results do not support the use of this dual regimen. However, as this dual HIV maintenance strategy was feasible and effective, over a period of 144 weeks, we suggest NVP plus 3TC warrants further evaluation as potential maintenance option in patients tolerating nevirapine. A properly sized multicentre non-inferiority trial is ongoing to further evaluate the value of this DT maintenance strategy.

CD4+ T Cell-Mimicking Nanoparticles Broadly Neutralize HIV-1 and Suppress Viral Replication through Autophagy

HIV-1 is a major global health challenge. The development of an effective vaccine and/or a therapeutic cure is a top priority. The creation of vaccines that focus an antibody response toward a particular epitope of a protein has shown promise, but the genetic diversity of HIV-1 hinders this progress. Here we developed an approach using nanoengineered CD4⁺ T cell membrane-coated nanoparticles (TNP). Not only do TNP effectively neutralize all strains of HIV-1, but they also selectively bind to infected cells and decrease the release of HIV-1 particles through an autophagy-dependent mechanism with no drug-induced off-target or cytotoxic effects on bystander cells.

Therapeutic strategies that provide effective and broad‐spectrum neutralization against HIV-1 infection are highly desirable. Here, we investigate the potential of nanoengineered CD4⁺ T cell membrane-coated nanoparticles (TNP) to neutralize a broad range of HIV-1 strains. TNP displayed outstanding neutralizing breadth and potency; they neutralized all 125 HIV-1-pseudotyped viruses tested, including global subtypes/recombinant forms, and transmitted/founder viruses, with a geometric mean 80% inhibitory concentration (IC₈₀) of 819 μg ml⁻¹ (range, 72 to 8,570 μg ml⁻¹). TNP also selectively bound to and induced autophagy in HIV-1-infected CD4⁺ T cells and macrophages, while having no effect on uninfected cells. This TNP-mediated autophagy inhibited viral release and reduced cell-associated HIV-1 in a dose- and phospholipase D1-dependent manner. Genetic or pharmacological inhibition of autophagy ablated this effect. Thus, we can use TNP as therapeutic agents to neutralize cell-free HIV-1 and to target HIV-1 gp120-expressing cells to decrease the HIV-1 reservoir.

N-Acetylcysteine Reverses Antiretroviral-Mediated Microglial Activation by Attenuating Autophagy-Lysosomal Dysfunction

Successful suppression of viral replication by combined antiretroviral therapy (cART) in HIV-1 infected individuals is paradoxically also accompanied by an increased prevalence of HIV-associated neurocognitive disorders (HAND) in these individuals. HAND is characterized by a state of chronic oxidative stress and inflammation. Microglia are extremely sensitive to a plethora of stimuli, including viral proteins and cART. The current study aimed to assess the effects of cART-mediated oxidative stress on the induction of inflammatory responses in microglia. In the present study, we chose a combination of three commonly used antiretroviral drugs—tenofovir disoproxil fumarate, emtricitabine, and dolutegravir. We demonstrated that exposure of microglia to the chosen cART cocktail induced generation of reactive oxygen species, subsequently leading to lysosomal dysfunction and dysregulated autophagy, ultimately resulting in the activation of microglia. Intriguingly, the potent antioxidant, N-acetylcysteine, reversed the damaging effects of cART. These in vitro findings were further corroborated in vivo wherein cART-treated HIV transgenic (Tg) rats demonstrated increased microglial activation, exaggerated lysosome impairment, and dysregulated autophagy in the prefrontal cortices compared with HIV Tg rats not exposed to cART. Similar to in vitro findings, the treatment of HIV Tg rats with N-acetylcysteine also mitigated the deleterious effects of cART. Taken together, our findings suggest that oxidative stress-mediated lysosomal dysfunction plays a critical role in the pathogenesis of HAND in drug-treated HIV-infected individuals and that antioxidant-mediated mitigation of oxidative stress could thus be considered as an adjunctive therapeutic strategy for ameliorating/dampening some of the neurological complications of HAND.

HIV-1 Sanctuary Sites-the Role of Membrane-Associated Drug Transporters and Drug Metabolic Enzymes

Despite significant advances in the treatment of human immunodeficiency virus-1 (HIV) infection with highly active antiretroviral drug therapy, the persistence of the virus in cellular and anatomic reservoirs is a major obstacle preventing total HIV eradication. Viral persistence could result from a variety of contributing factors including, but not limited to, non-adherence to treatment and adverse drug reactions, latently infected cells carrying replication-competent virus, drug-drug interactions, and inadequate antiretroviral drug (ARV) concentrations reached in several anatomic sites such as the brain, testis, and gut-associated lymphoid tissues. The distribution of ARVs at specific sites of infection is primarily dependent on drug physicochemical properties and drug plasma protein binding, as well as drug efflux, influx, and metabolic processes. A thorough understanding of the functional roles of drug transporters and metabolic enzymes in the disposition of ARVs in immune cell types and tissues that are characterized as HIV reservoirs and sanctuaries is critical to overcome the challenge of suboptimal drug distribution at sites of persistent HIV infection. This review summarizes the current knowledge related to the expression and function of drug transporters and metabolic enzymes in HIV cellular and anatomic reservoirs, and their potential contribution to drug-drug interactions and insufficient drug concentration at these sites.

Ultrasensitive Human Immunodeficiency Virus Type 1 Viral Load as a Marker of Treatment Choice for Simplification Strategies

Background

Using 3 randomized Protease inhibitor (PI) monotherapy studies: Kalesolo, Dream and Monoi, we performed a pooled-analysis. Our objective was to determine in PI monotherapy and standard tritherapy: 1) distribution of ultrasensitive viral load (USVL) at week 96 (W96); 2) factors associated with virological failure (VF) at W96 and 3) factors associated with USVL<1 copy at W96.

Methods

VF was defined as 2 consecutive measurements of Human Immunodeficiency Virus Type 1 RNA viral load>50 copies/mL and analysed in Intention-To-Treat. A logistic model was used to investigate which variables were predictive of a VF and Fisher test to investigate differences in USVL at W96.

Results

Among 609 patients, 73% were male with median age of 44.4 years (IQR 39.8-52.1), baseline CD4/CD8 ratio was 0.8 (IQR 0.6-1.10), baseline CD4 was 564.5/mm3 (IQR 422-707) and 59% presented a baseline USVL<1 copy/mL. At W96, the proportion of USVL<1 copy/mL was significantly different between PI monotherapy and standard tritherapy in pooled-analysis (65% versus 74%; p=0.04). Overall, baseline USVL<1copy/mL, tritherapy and to be a female were associated with USVL<1 copy/mL at W96 (p<0.0001, p=0.049 and p=0.006). In PI monotherapy receiving DRV/r was associated with USVL<1 copy/mL at W96 (p=0.003). Factors associated to virological succes at W96 were higher baseline CD4 (p=0.034) and baseline USVL<1 copy/mL (p=0.0005).

Conclusion

Pooled-analysis of 3 PI monotherapy trials showed better efficacy of tritherapy in terms of USVL at W96. Furthermore regarding USVL at W96, to receive LPV/r seems to be more deleterious than DRV/r. Baseline USVL impacts VF at W96 more specifically in tritherapy arm.

Clinical Trials Registration

NCT00421551, NCT00946595, and NCT00140751.

Antiretroviral-Mediated Microglial Activation Involves Dysregulated Autophagy and Lysosomal Dysfunction

In the era of combined antiretroviral therapy (cART), as infected individuals continue to have longer lifespans, there is also an increased prevalence of HIV-associated neurocognitive disorders (HAND). Inflammation is one of the underlying features of HAND, with the role of viral proteins and antiretroviral drugs implicated in this process. Microglia are extremely sensitive to a plethora of stimuli, including viral products and cART. The current study was undertaken to understand the molecular mechanism(s) underlying cART-mediated activation of microglia. Herein we chose a combination of three commonly used drugs, tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and dolutegravir (DTG). We demonstrated that exposure of microglia to this cART cocktail induced lysosomal membrane permeabilization (LMP), which subsequently resulted in impaired lysosomal functioning involving elevated pH and decreased cathepsin D (CTSD) activity. cART exposure of microglia resulted in increased formation of autophagosomes as demonstrated by a time-dependent increase of autophagy markers, with a concomitant defect in the fusion of the lysosomes with the autophagosome. Taken together, our findings suggest a novel mechanism by which cART impairs lysosomal functioning, resulting in dysregulated autophagy and increased neuroinflammation. Interventions aimed at lysosome protection could likely be envisioned as promising therapeutic targets for abrogating cART-mediated microglia activation, which in turn, could thus be considered as adjunctive therapeutics for the treatment of HAND pathogenesis.

Cell-type specific differences in antiretroviral penetration and the effects of HIV-1 Tat and morphine among primary human brain endothelial cells, astrocytes, pericytes, and microglia

The inability to achieve adequate intracellular antiretroviral concentrations may contribute to HIV persistence within the brain and to neurocognitive deficits in opioid abusers. To investigate, intracellular antiretroviral concentrations were measured in primary human astrocytes, microglia, pericytes, and brain microvascular endothelial cells (BMECs), and in an immortalized brain endothelial cell line (hCMEC/D3). HIV-1 Tat and morphine effects on intracellular antiretroviral concentrations also were evaluated. After pretreatment for 24 h with vehicle, HIV-1 Tat, morphine, or combined Tat and morphine, cells were incubated for 1 h with equal concentrations of a mixture of tenofovir, emtricitabine, and dolutegravir at one of two concentrations (5 μM or 10 μM). Intracellular drug accumulation was measured using LC-MS/MS. Drug penetration differed depending on the drug, the extracellular concentration used for dosing, and cell type. Significant findings included: 1) Dolutegravir (at 5 μM or 10 μM) accumulated more in HBMECs than other cell types. 2) At 5 μM, intracellular emtricitabine levels were higher in microglia than other cell types; while at 10 μM, emtricitabine accumulation was greatest in HBMECs. 3) Tenofovir (5 or 10 μM extracellular dosing) displayed greater accumulation inside HBMECs than in other cell types. 4) After Tat and/or morphine pretreatment, the relative accumulation of antiretroviral drugs was greater in morphine-exposed HBMECs compared to other treatments. The opposite effect was observed in astrocytes in which morphine exposure decreased drug accumulation. In summary, the intracellular accumulation of antiretroviral drugs differed depending on the particular drug involved, the concentration of the applied antiretroviral drug, and the cell type targeted. Moreover, morphine, and to a lesser extent Tat, exposure also had differential effects on antiretroviral accumulation. These data highlight the complexity of optimizing brain-targeted HIV therapeutics, especially in the setting of chronic opioid use or misuse.

Simultaneous determination of intracellular concentrations of tenofovir, emtricitabine, and dolutegravir in human brain microvascular endothelial cells using liquid chromatography-tandem mass spectrometry (LC-MS/MS)

Combination antiretroviral therapy (cART) regimens are recommended for HIV patients to better achieve and maintain plasma viral suppression. Despite adequate plasma viral suppression, HIV persists inside the brain, which is, in part thought to result from poor brain penetration of antiretroviral drugs. In this study, a simple and ultra-sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of tenofovir, emtricitabine, and dolutegravir in cell lysates of an immortalized human brain microvascular endothelial cell line (hCMEC/D3) was developed and validated. Analytes were separated on a reverse phase C18 column using water and 0.1% formic acid in acetonitrile as mobile phases. The analytes were detected using positive electrospray ionization mode with multiple reaction monitoring (MRM). The assay was linear in the concentration range of 0.1-100 ng mL-1 for all analytes. Intra- and inter-assay precision and accuracy were within ±13.33% and ±10.53%, respectively. This approach described herein was used to determine the intracellular accumulation of tenofovir, emtricitabine, dolutegravir simultaneously in hCMEC/D3 cells samples.

Singularities of nevirapine metabolism: from sex-dependent differences to idiosyncratic toxicity

Nevirapine (NVP) is a first-generation non-nucleoside reverse transcriptase inhibitor widely used for the treatment and prophylaxis of human immunodeficiency virus infection. The drug is taken throughout the patient's life and, due to the availability of an extended-release formulation, it is administered once daily. This antiretroviral is one of the scarce examples of drugs with prescription criteria based on sex, in order to prevent adverse reactions. The therapy with NVP has been associated with potentially life-threatening liver and idiosyncratic skin toxicity. Multiple evidence has emerged regarding the formation of electrophilic NVP metabolites as crucial for adverse idiosyncratic reactions. The formation of reactive metabolites that yield covalent adducts with proteins has been demonstrated in patients under NVP-based treatment. Interestingly, several pharmacogenetic- and sex-related factors associated with NVP toxicity can be mechanistically explained by an imbalance toward increased formation of NVP-derived reactive metabolites and/or impaired detoxification capability. Moreover, the haptenation of self-proteins by these reactive species provides a plausible link between NVP bioactivation and immunotoxicity, further supporting the relevance of this toxicokinetics hypothesis. In the current paper, we review the existing knowledge and recent developments on NVP metabolism and their relation to NVP toxicity.

CNS penetration of ART in HIV-infected children

Background

Paediatric data on CNS penetration of antiretroviral drugs are scarce.

Objectives

To evaluate CNS penetration of antiretroviral drugs in HIV-infected children and explore associations with neurocognitive function.

Patients and methods

Antiretroviral drug levels were measured in paired CSF and blood samples of clinically stable HIV-infected children between 8 and 18 years old on long-term combined ART. Plasma drug concentrations were corrected for protein binding. We evaluated CNS penetration using CSF/plasma ratios and compared CSF concentrations with the IC50 as a surrogate marker for effectiveness. Blood-brain barrier permeability was assessed for possible confounding. Associations with neurocognitive function were explored using linear regression analysis.

Results

Median CSF/plasma ratios (IQR) were: lopinavir 0.059 (0.024-0.157, n = 7), efavirenz 0.681 (0.555-0.819, n = 12), tenofovir 0.021 (0.020-0.024, n = 4), lamivudine 0.464 (0.331-0.607, n = 17), emtricitabine 0.365 (0.343-0.435, n = 3), nevirapine 1.203 (n = 1), zidovudine 0.718 (0.711-1.227, n = 5) and abacavir 1.344 (0.670-2.450, n = 10). CSF concentrations were below the IC50 for tenofovir (100%), emtricitabine (100%), abacavir (50%) and zidovudine (17%). Lamivudine, lopinavir, efavirenz and nevirapine concentrations were all above the IC50. All participants were virologically suppressed in blood and CSF. CSF drug concentrations were not associated with blood-brain barrier permeability or neurocognitive function.

Conclusions

We showed adequate CSF concentrations of lamivudine, lopinavir, efavirenz and nevirapine, and potential suboptimal CSF concentrations of tenofovir, abacavir and emtricitabine in long-term treated HIV-infected children. None the less, the use of combined antiretroviral drugs led to adequate viral suppression.

The clinical pharmacology of integrase inhibitors

Introduction: Treatment of HIV infection has consistently evolved in the last three decades. A steady improvement in efficacy tolerability, safety, and practical aspects of treatment intake has made HIV infection much easier to manage over the long term, and in optimal treatment conditions the life expectancy of persons living with HIV infection now approaches the values of the general population. The last category of antiretrovirals to be fully developed for clinical use is the one of strand-transfer integrase inhibitors (INSTIs). Areas covered: In this review, the evolution of the knowledge on INSTIs use in the clinical setting is reviewed, analyzed, and interpreted. Emphasis is placed on the properties possibly accounting for several superiority results achieved by INSTIs in non-inferiority designed comparative clinical trials, which led to their inclusion as first line options in all versions of HIV therapeutic guidelines. Expert commentary: Some unprecedented clinical-pharmacological properties of INSTIs, such as their rapid and sustained action against HIV replication, the optimal tolerability and safety profile and a clinically proven robust genetic barrier are the main factors justifying the successful clinical use of INSTIs. Based on these unique features, novel INSTIs-based treatment modalities are being developed, including the reduction of antiretroviral regimens to two drugs only.

Antiretroviral concentrations and surrogate measures of efficacy in the brain tissue and CSF of preclinical species

1. Antiretroviral concentrations in cerebrospinal fluid (CSF) are used as surrogate for brain tissue, although sparse data support this. We quantified antiretrovirals in brain tissue across preclinical models, compared them to CSF, and calculated 90% inhibitory quotients (IQ₉₀) for nonhuman primate (NHP) brain tissue. Spatial distribution of efavirenz was performed by mass-spectrometry imaging (MSI). 2. HIV or RT-SHIV-infected and uninfected animals from two humanized mouse models (hemopoietic-stem cell/RAG2-, n = 36; bone marrow-liver-thymus/BLT, n =13) and an NHP model (rhesus macaque, n =18) were dosed with six antiretrovirals. Brain tissue, CSF (NHPs), and plasma were collected at necropsy. Drug concentrations were measured by LC-MS/MS. Rapid equilibrium dialysis determined protein binding in NHP brain. 3. Brain tissue penetration of most antiretrovirals were >10-fold lower (p < 0.02) in humanized mice than NHPs. NHP CSF concentrations were >13-fold lower (p <0.02) than brain tissue with poor agreement except for efavirenz (r = 0.91, p = 0.001). Despite 97% brain tissue protein binding, efavirenz achieved IQ₉₀>1 in all animals and 2-fold greater white versus gray matter concentration. 4. Brain tissue penetration varied across animal models for all antiretrovirals except raltegravir, and extrapolating brain tissue concentrations between models should be avoided. With the exception of efavirenz, CSF is not a surrogate for brain tissue concentrations.

Pharmaceutical Approaches to HIV Treatment and Prevention

Human immunodeficiency virus (HIV) infection continues to pose a major infectious disease threat worldwide. It is characterized by the depletion of CD4+ T cells, persistent immune activation, and increased susceptibility to secondary infections. Advances in the development of antiretroviral drugs and combination antiretroviral therapy have resulted in a remarkable reduction in HIV-associated morbidity and mortality. Antiretroviral therapy (ART) leads to effective suppression of HIV replication with partial recovery of host immune system and has successfully transformed HIV infection from a fatal disease to a chronic condition. Additionally, antiretroviral drugs have shown promise for prevention in HIV pre-exposure prophylaxis and treatment as prevention. However, ART is unable to cure HIV. Other limitations include drug-drug interactions, drug resistance, cytotoxic side effects, cost, and adherence. Alternative treatment options are being investigated to overcome these challenges including discovery of new molecules with increased anti-viral activity and development of easily administrable drug formulations. In light of the difficulties associated with current HIV treatment measures, and in the continuing absence of a cure, the prevention of new infections has also arisen as a prominent goal among efforts to curtail the worldwide HIV pandemic. In this review, the authors summarize currently available anti-HIV drugs and their combinations for treatment, new molecules under clinical development and prevention methods, and discuss drug delivery formats as well as associated challenges and alternative approaches for the future.

Persistent central nervous system immune activation following more than 10 years of effective HIV antiretroviral treatment

OBJECTIVE

Low-grade immune activation is common in people living with HIV (PLHIV), despite long-term viral suppression by antiretroviral therapy (ART). The clinical significance of this activation remains unclear. The aim of this study was to examine residual intrathecal immune activation in relation to signs of neuronal injury and neurocognitive impairment in PLHIV who had been virally suppressed on ART for more than 10 years.

DESIGN/METHODS

Twenty neuroasymptomatic PLHIV on suppressive ART for a median of 13.2 years were retrospectively identified from the longitudinal prospective Gothenburg HIV cerebrospinal fluid (CSF) study. HIV-RNA, neopterin, and neurofilament light protein (NFL) levels were measured in paired plasma and CSF samples. Pretreatment samples were available for 14 patients. Cognitive function was assessed by CogState at follow-up.

RESULTS

CSF neopterin decreased from a median (IQR) of 17.8 (10.6-29.7) to 6.1 (4.6-8.0) nmol/l during treatment (P < 0.001). In 11 out of 20 participants (55%), CSF neopterin levels were above the upper normal reference limit (5.8 nmol/l) at follow-up. Age-adjusted CSF NFL decreased to within-normal levels from a median of (IQR) 1179 (557-2707) to 415 (292-610) ng/l (P < 0.001). No significant correlations were found between CSF neopterin and CSF NFL or neurocognitive performance.

CONCLUSION

Although CSF neopterin decreased significantly, more than 50% of the patients had CSF concentrations above the upper normal reference value despite more than 10 years of suppressive ART. We found no correlation between CSF neopterin, CSF NFL or neurocognitive performance at follow-up, indicating that low-grade immune activation during suppressive ART may be clinically benign.

Clinical Pharmacokinetics and Pharmacodynamics of Drugs in the Central Nervous System

Despite contributing significantly to the burden of global disease, the translation of new treatment strategies for diseases of the central nervous system (CNS) from animals to humans remains challenging, with a high attrition rate in the development of CNS drugs. The failure of clinical trials for CNS therapies can be partially explained by factors related to pharmacokinetics/pharmacodynamics (PK/PD), such as lack of efficacy or improper selection of the initial dosage. A focused assessment is needed for CNS-acting drugs in first-in-human studies to identify the differences in PK/PD from animal models, as well as to choose the appropriate dose. In this review, we summarize the available literature from human studies on the PK and PD in brain tissue, cerebrospinal fluid, and interstitial fluid for drugs used in the treatment of psychosis, Alzheimer's disease and neuro-HIV, and address critical questions in the field. We also explore newer methods to characterize PK/PD relationships that may lead to more efficient dose selection in CNS drug development.

Determination of nucleosidic/tidic reverse transcriptase inhibitors in plasma and cerebrospinal fluid by ultra-high-pressure liquid chromatography coupled with tandem mass spectrometry

Nucleoside reverse transcriptase inhibitors (NRTIs) have been the first class of antiretroviral drugs used against HIV infection. Despite NRTI-free regimens have been eagerly sought over the years in an effort for treatment simplification, NRTIs remain in most antiretroviral combination treatment. There has been generally a limited interest for their therapeutic drug monitoring, arguably because NRTIs levels measured in plasma poorly predict the concentration of pharmacologically active metabolites in cells. Plasma concentrations do impact cellular levels, while large differences between NRTIs have been found with regard to their ability to distribute into the cerebrospinal fluid (CSF) compartment. The renewed interest for the measurements of NRTIs concentrations in plasma and CSF was raised by ongoing efforts to understand some instances of toxicity or for determining their actual implication in the development of HIV-associated neurological disorders. In this context, a 5-min multiplex ultra-high-pressure chromatography tandem mass spectrometry (UHPLC-MS/MS) analysis in human plasma and CSF was developed for NRTIs used in clinical practice: abacavir, emtricitabine, lamivudine, tenofovir and zidovudine along with zidovudine glucuronide (Gln-ZDV). The 200-fold dilution of blank human plasma was shown to be a reliable surrogate matrix for quantification of NRTIs and Gln-ZDV in CSF. Both methodologies were fully validated over the clinically relevant concentrations, and satisfactorily fulfilled all parameters for bioanalytical methods validation. This sensitive, rapid, and robust UHPLC-MS/MS assay offers a methodology for increasing our understanding of the ability of NRTIs to cross the blood-brain barrier and their potential implication in neuropsychological disorders observed in HIV-infected patients.

Induction of autophagy by PI3K/MTOR and PI3K/MTOR/BRD4 inhibitors suppresses HIV-1 replication

In this study, we investigated the effects of the dual phosphatidylinositol 3-kinase/mechanistic target of rapamycin (PI3K/MTOR) inhibitor dactolisib (NVP-BEZ235), the PI3K/MTOR/bromodomain-containing protein 4 (BRD4) inhibitor SF2523, and the bromodomain and extra terminal domain inhibitor JQ1 on the productive infection of primary macrophages with human immunodeficiency type-1 (HIV). These inhibitors did not alter the initial susceptibility of macrophages to HIV infection. However, dactolisib, JQ1, and SF2523 all decreased HIV replication in macrophages in a dose-dependent manner via degradation of intracellular HIV through autophagy. Macrophages treated with dactolisib, JQ1, or SF2523 displayed an increase in LC3B lipidation combined with SQSTM1 degradation without inducing increased cell death. LC3B-II levels were further increased in the presence of pepstatin A suggesting that these inhibitors induce autophagic flux. RNA interference for ATG5 and ATG7 and pharmacological inhibitors of autophagosome-lysosome fusion and of lysosomal hydrolases all blocked the inhibition of HIV. Thus, we demonstrate that the mechanism of PI3K/MTOR and PI3K/MTOR/BRD4 inhibitor suppression of HIV requires the formation of autophagosomes, as well as their subsequent maturation into autolysosomes. These data provide further evidence in support of a role for autophagy in the control of HIV infection and open new avenues for the use of this class of drugs in HIV therapy.

Treating HIV Infection in the Central Nervous System

Combination antiretroviral treatment is associated with clear benefits in HIV-positive subjects, and is also effective in the central nervous system (CNS), meaning HIV-associated dementia is now an uncommon event. Nevertheless, a significant number of patients show symptoms of neurocognitive impairment which may negatively affect their quality of life. Although several risk factors for HIV-associated neurocognitive disorders have been identified, there is no clear recommendation for their prevention and management. In this review, the penetration of drugs into the cerebrospinal fluid/CNS is discussed as well as the viral and clinical consequences associated with higher/lower compartmental exposure. We also review the potential interventions according to the currently identified underlying mechanisms, including persistent CNS immune activation, legacy effects, low-level viral replication and escape, co-morbidities, and antiretroviral-associated direct and indirect 'neurotoxicity'. Adjunctive therapies and interventions (including neuro-rehabilitation) are then briefly discussed. The treatment of HIV infection in the CNS is a complex area of therapeutics requiring multidisciplinary interventions and further study.

Current views on interferon therapy for HIV

INTRODUCTION

Knowledge of IFN-antiviral activity against HIV infection dates from the first years of the AIDS epidemic. Recombinant IFN had an inhibitory effect on HIV and was not toxic to peripheral blood mononuclear cells (PBMC), and this finding was the basis for the design of clinical trials that evaluated the potential role of IFN-alpha as an inhibitor of HIV replication.

AREAS COVERED

This review summarizes the history of IFN-alpha in the treatment of HIV infection with reviews of studies performed in different clinical settings; in the pre-highly active antiretroviral therapy (HAART) era, as part of a structured treatment interruption (STI) strategy, in acute HIV infection, as part of salvage therapy, and eliminating the HIV reservoir.

EXPERT OPINION

The role of IFN-alpha has been dismissed in the area of HIV therapy. For this reason, with the advent of HAART, which substantially reduced mortality and the appearance of AIDS, IFN-alpha ceased to be used as an antiretroviral agent in different strategies. In contrast, because of the promising results achieved with IFN-alpha therapy in eliminating the HIV viral reservoir, this may constitute the main research field for IFN-alpha in the HIV setting.

Discordant CSF/plasma HIV-1 RNA in patients with unexplained low-level viraemia

The central nervous system has been proposed as a sanctuary site where HIV can escape antiretroviral control and develop drug resistance. HIV-1 RNA can be at higher levels in CSF than plasma, termed CSF/plasma discordance. We aimed to examine whether discordance in CSF is associated with low level viraemia (LLV) in blood. In this MRC-funded multicentre study, we prospectively recruited patients with LLV, defined as one or more episode of unexplained plasma HIV-1 RNA within 12 months, and undertook CSF examination. Separately, we prospectively collected CSF from patients undergoing lumbar puncture for a clinical indication. Patients with durable suppression of viraemia and no evidence of CNS infection were identified as controls from this group. Factors associated with CSF/plasma HIV-1 discordance overall were examined. One hundred fifty-three patients were recruited across 13 sites; 40 with LLV and 113 undergoing clinical lumbar puncture. Seven of the 40 (18 %) patients with LLV had CSF/plasma discordance, which was significantly more than 0/43 (0 %) with durable suppression in blood from the clinical group (p = 0.005). Resistance associated mutations were shown in six CSF samples from discordant patients with LLV (one had insufficient sample for testing), which affected antiretroviral therapy at sampling in five. Overall discordance was present in 20/153 (13 %) and was associated with nadir CD4 but not antiretroviral concentrations in plasma or CSF. CSF/plasma discordance is observed in patients with LLV and is associated with antiretroviral resistance associated mutations in CSF. The implications for clinical practice require further investigation.

Screening for Neurocognitive Impairment in HIV-Infected Individuals at First Contact after HIV Diagnosis: The Experience of a Large Clinical Center in Northern Italy

Neurocognitive disorders are emerging, probably underestimated, complications in HIV-infected people. The aim of the study was to assess neurocognitive profiles of newly detected HIV-infected patients. We performed an observational retrospective single-cohort study. Illiterates and patients with neurologic symptoms or previous psychiatric diagnosis were excluded. Neuropsychological profiles were assessed using a validated battery of neuropsychological tests. We included 206 patients; with males representing the majority of them (85%). Risk factors for HIV acquisition were unprotected sexual intercourse (homo/bisexual in 39.8% and heterosexual in 60.2%). Thirty-nine patients (18.9%) were previous injection drug users, while 41 (19.9%) were alcohol abusers. Mean education was 11.1 years (SD--standard deviation--3.7). A high prevalence of HIV-associated neurocognitive disorders (HAND, 47.1%) was present in HIV-infected patients: particularly, asymptomatic neurocognitive impairment (ANI) was found in 30.6%, mild neurocognitive disorder (MND) in 15% and HIV-associated dementia (HAD) in 1.5%. Male gender, low degree of education, AIDS diagnosis and gepatitis B virus (HBV) co-infection were factors independently associated with HAND in a multivariable logistic regression model. Our data suggest that patient-specific factors and AIDS diagnosis have a certain kind of impact in HAND occurrence. A complete neuropsychological screening must be recommended in all patients at HIV-infection diagnosis.

Immuno-Pharmacological Targeting of Virus-Containing Compartments in HIV-1-Infected Macrophages

In addition to CD4 T lymphocytes, HIV-1 infects tissue macrophages that can actively accumulate infectious virions in vacuolar subcellular structures mostly connected to the plasma membrane and recently termed virus-containing compartments (VCCs). The VCC-associated HIV-1 reservoir of infected macrophages can be either increased or depleted by immunologic and pharmacologic agents, at least in vitro, thus suggesting that these factors (or related molecules) could be effective in curtailing the macrophage-associated HIV-1 reservoir in infected individuals receiving combination antiretroviral therapy (cART). Here we review evidence on the pathogenic role of tissue macrophages as long-term viral reservoirs in vivo and upon in vitro infection with a particular emphasis on the immuno-pharmacological modulation of VCCs.

HIV protease inhibitors disrupt astrocytic glutamate transporter function and neurobehavioral performance

Objective:

The neurotoxic actions of the HIV protease inhibitors, amprenavir (APV) and lopinavir (LPV) were investigated.

Design:

With combination antiretroviral therapy (cART), HIV-infected persons exhibit neurocognitive impairments, raising the possibility that cART might exert adverse central nervous system (CNS) effects. We examined the effects of LPV and APV using in-vitro and in-vivo assays of CNS function.

Methods:

Gene expression, cell viability and amino-acid levels were measured in human astrocytes, following exposure to APV or LPV. Neurobehavioral performance, amino-acid levels and neuropathology were examined in HIV-1 Vpr transgenic mice after treatment with APV or LPV.

Results:

Excitatory amino-acid transporter-2 (EAAT2) expression was reduced in astrocytes treated with LPV or APV, especially LPV (P < 0.05), which was accompanied by reduced intracellular l-glutamate levels in LPV-treated cells (P < 0.05). Treatment of astrocytes with APV or LPV reduced the expression of proliferating cell nuclear antigen (PCNA) and Ki-67 (P < 0.05) although cell survival was unaffected. Exposure of LPV to astrocytes augmented glutamate-evoked transient rises in [Ca_i] (P < 0.05). Vpr mice treated with LPV showed lower concentrations of l-glutamate, l-aspartate and l-serine in cortex compared with vehicle-treated mice (P < 0.05). Total errors in T-maze assessment were increased in LPV and APV-treated animals (P < 0.05). EAAT2 expression was reduced in the brains of protease inhibitor-treated animals, which was associated with gliosis (P < 0.05).

Conclusion:

These results indicated that contemporary protease inhibitors disrupt astrocyte functions at therapeutic concentrations with enhanced sensitivity to glutamate, which can lead to neurobehavioral impairments. ART neurotoxicity should be considered in future therapeutic regimens for HIV/AIDS.

In vivo platforms for analysis of HIV persistence and eradication

HIV persistence in patients undergoing antiretroviral therapy is a major impediment to the cure of HIV/AIDS. The molecular and cellular mechanisms underlying HIV persistence in vivo have not been fully elucidated. This lack of basic knowledge has hindered progress in this area. The in vivo analysis of HIV persistence and the implementation of curative strategies would benefit from animal models that accurately recapitulate key aspects of the human condition. This Review summarizes the contribution that humanized mouse models of HIV infection have made to the field of HIV cure research. Even though these models have been shown to be highly informative in many specific areas, their great potential to serve as excellent platforms for discovery in HIV pathogenesis and treatment has yet to be fully developed.

Peginterferon α-2a for the treatment of HIV infection

INTRODUCTION

Novel approaches are urgently needed to achieve the next level of control of HIV infection beyond antiretroviral medications that will lead to the ultimate goal of curing HIV infection. Exploiting the innate immune system control of HIV is one possible component of that strategy with pegylated interferon α representing a well-characterized agent that is being applied to this effort.

AREAS COVERED

In this review, the authors summarize the history of interferon α treatment in the setting of HIV infection with a focus on clinical trials that examined the downstream effects on innate immune responses. More recently, clinical trials that administered pegylated interferon α-2a have demonstrated which interferon-stimulated genes are associated with its antiviral effects and which of these host-restriction factors may play a role in limiting the magnitude of the HIV reservoir.

EXPERT OPINION

The potential to exploit interferon α as part of a cure strategy is provocative. Whether key interferon-induced antiviral factors can be upregulated sufficiently to affect the reservoir is unknown. Additional research employing pegylated interferon α-2a is needed to identify which innate immune pathways are candidate targets for novel biological therapies for the potential cure of HIV infection.

HIV-1 CNS in vitro infectivity models based on clinical CSF samples

BACKGROUND

The concentration of antiretrovirals in CSF is often utilized as a surrogate for CNS drug exposure. This measurement does not consider pharmacodynamic or combinative effects of ART. We have developed a novel endpoint measurement to assess antiretroviral activity of CSF from subjects on ART.

METHODS

CSF samples were obtained from patients receiving tenofovir/emtricitabine (245/200 mg once daily) with either rilpivirine (25 mg once daily) or lopinavir/ritonavir/maraviroc (400/100/150 mg twice daily) and HIV-uninfected controls. Antiviral activity of ART-containing CSF was assessed in cell cultures using PBMCs and neuro-derived glial (U87) and astrocyte (373) cell lines. Infectivity model half-maximal inhibitory concentration (IMIC50) values were calculated and expressed as -log2IMIC50. Results were correlated with CSF antiretroviral concentrations.

RESULTS

Compared with controls, CSF from both ART studies demonstrated in vitro antiretroviral activity in all models. CSF antiretroviral activity of patients on lopinavir/ritonavir/maraviroc was significantly greater than that of patients on rilpivirine [-log2IMIC50 (95% CI) 4.82 (4.74-4.89) versus 3.43 (3.33-3.54) in PBMCs, 3.06 (2.98-3.15) versus 2.56 (2.46-2.65) in U87 cells and 6.00 (6.11-5.88) versus 4.90 (5.09-4.72) in 373 cells, respectively]. Positive correlations were observed for individual CSF antiretroviral activity in different cellular models with CSF concentrations of rilpivirine (P = 0.040 in 373 cells) and lopinavir (P = 0.048 in 373 cells), but not maraviroc.

CONCLUSIONS

Antiviral activity of CSF from patients on ART was successfully calculated and was greater with a regimen containing four active drugs compared with three active drugs. The use of neuro-derived cell lines alongside PBMCs to assess the effect of ART on CSF may act as a useful future clinical research tool.

Induction of Heme Oxygenase-1 Deficiency and Associated Glutamate-Mediated Neurotoxicity Is a Highly Conserved HIV Phenotype of Chronic Macrophage Infection That Is Resistant to Antiretroviral Therapy

Expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) is significantly reduced in the brain prefrontal cortex of HIV-positive individuals with HIV-associated neurocognitive disorders (HAND). Furthermore, this HO-1 deficiency correlates with brain viral load, markers of macrophage activation, and type I interferon responses. In vitro, HIV replication in monocyte-derived macrophages (MDM) selectively reduces HO-1 protein and RNA expression and induces production of neurotoxic levels of glutamate; correction of this HO-1 deficiency reduces neurotoxic glutamate production without an effect on HIV replication. We now demonstrate that macrophage HO-1 deficiency, and the associated neurotoxin production, is a conserved feature of infection with macrophage-tropic HIV-1 strains that correlates closely with the extent of replication, and this feature extends to HIV-2 infection. We further demonstrate that this HO-1 deficiency does not depend specifically upon the HIV-1 accessory genes nef, vpr, or vpu but rather on HIV replication, even when markedly limited. Finally, antiretroviral therapy (ART) applied to MDM after HIV infection is established does not prevent HO-1 loss or the associated neurotoxin production. This work defines a predictable relationship between HIV replication, HO-1 loss, and neurotoxin production in MDM that likely reflects processes in place in the HIV-infected brains of individuals receiving ART. It further suggests that correcting this HO-1 deficiency in HIV-infected MDM could provide neuroprotection above that provided by current ART or proposed antiviral therapies directed at limiting Nef, Vpr, or Vpu functions. The ability of HIV-2 to reduce HO-1 expression suggests that this is a conserved phenotype among macrophage-tropic human immunodeficiency viruses that could contribute to neuropathogenesis.

IMPORTANCE

The continued prevalence of HIV-associated neurocognitive disorders (HAND) underscores the need for adjunctive therapy that targets the neuropathological processes that persist in antiretroviral therapy (ART)-treated HIV-infected individuals. To this end, we previously identified one such possible process, a deficiency of the antioxidative and anti-inflammatory enzyme heme oxygenase-1 (HO-1) in the brains of individuals with HAND. In the present study, our findings suggest that the HO-1 deficiency associated with excess glutamate production and neurotoxicity in HIV-infected macrophages is a highly conserved phenotype of macrophage-tropic HIV strains and that this phenotype can persist in the macrophage compartment in the presence of ART. This suggests a plausible mechanism by which HIV infection of brain macrophages in ART-treated individuals could exacerbate oxidative stress and glutamate-induced neuronal injury, each of which is associated with neurocognitive dysfunction in infected individuals. Thus, therapies that rescue the HO-1 deficiency in HIV-infected individuals could provide additional neuroprotection to ART.

Relevance of retrovirus quantification in cerebrospinal fluid for neurologic diagnosis

Different human retroviruses, such as Human Immunodeficiency Virus (HIV) and Human T-cell Lymphotropic Virus (HTLV), can cause neurologic infection. However, a definitive diagnosis may be hampered by several factors. Quantification of the viral or proviral load in cerebrospinal fluid (CSF) may be helpful in the diagnosis of nervous system disorders due to retroviral infection and may influence the treatment approach. The present work discusses retrovirus infection and neurologic impairment, as well as the usefulness of the determination of the HIV and HTLV proviral or viral load in cerebrospinal fluid in cases of neurologic disorder, in light of recent advances in this field. This study also discusses the different molecular techniques for quantifying the proviral load (real-time quantitative PCR, droplet digital PCR, and semi-nested real-time reverse transcription PCR) that are currently available.

HIV-1 Nef drives macrophages into hiding

In this issue of Blood, Vérollet et al show that expression of the HIV-1–derived protein Nef alters the migratory mode adopted by macrophages, enhancing macrophage tissue infiltration and explaining the observed accumulation of tissue-resident macrophages in some HIV-infected patients.