Central nervous system penetration effectiveness of antiretroviral drugs and neuropsychological impairment in the Ontario HIV Treatment Network Cohort Study

Antiretroviral drugs from multiple classes induce loss of excitatory synapses between hippocampal neurons in culture

Introduction: Antiretroviral (ARV) drugs have improved prognoses for people living with HIV. However, HIV-associated neurocognitive disorders (HAND) persist despite undetectable viral loads. Some ARVs have been linked to neuropsychiatric effects that may contribute to HAND. Synapse loss correlates with cognitive decline in HAND and synaptic deficits may contribute to the neuropsychiatric effects of ARV drugs. Methods: Using an automated high content assay, rat hippocampal neurons in culture expressing PSD95-eGFP to label glutamatergic synapses and mCherry to fill neuronal structures were imaged before and after treatment with 25 clinically used ARVs. Results and Discussion: At a concentration of 10 μM the protease inhibitors nelfinavir and saquinavir, the non-nucleoside reverse transcriptase inhibitors etravirine and the 8-OH metabolite of efavirenz, the integrase inhibitor bictegravir, and the capsid inhibitor lenacapavir produced synaptic toxicity. Only lenacapavir produced synapse loss at the nanomolar concentrations estimated free in the plasma, although all 4 ARV drugs induced synapse loss at Cmax. Evaluation of combination therapies did not reveal synergistic synaptic toxicity. Synapse loss developed fully by 24 h and persisted for at least 3 days. Bictegravir-induced synapse loss required activation of voltage-gated Ca2+ channels and bictegravir, etravirine, and lenacapavir produced synapse loss by an excitotoxic mechanism. These results indicate that select ARV drugs might contribute to neuropsychiatric effects in combination with drugs that bind serum proteins or in disease states in which synaptic function is altered. The high content imaging assay used here provides an efficient means to evaluate new drugs and drug combinations for potential CNS toxicity.

Deep analysis of CD4 T cells in the rhesus CNS during SIV infection

Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic inflammation in the central nervous system (CNS)-known as Neuro-HIV- persist. As primary targets for HIV-1 with the ability to survey and populate the CNS and interact with myeloid cells to co-ordinate neuroinflammation, CD4 T cells are pivotal in Neuro-HIV. Despite their importance, our understanding of CD4 T cell distribution in virus-targeted CNS tissues, their response to infection, and potential recovery following initiation of ART remain limited. To address these gaps, we studied ten SIVmac251-infected rhesus macaques using an ART regimen simulating suboptimal adherence. We evaluated four macaques during the acute phase pre-ART and six during the chronic phase. Our data revealed that HIV target CCR5+ CD4 T cells inhabit both the brain parenchyma and adjacent CNS tissues, encompassing choroid plexus stroma, dura mater, and the skull bone marrow. Aligning with the known susceptibility of CCR5+ CD4 T cells to viral infection and their presence within the CNS, high levels of viral RNA were detected in the brain parenchyma and its border tissues during acute SIV infection. Single-cell RNA sequencing of CD45+ cells from the brain revealed colocalization of viral transcripts within CD4 clusters and significant activation of antiviral molecules and specific effector programs within T cells, indicating CNS CD4 T cell engagement during infection. Acute infection led to marked imbalance in the CNS CD4/CD8 ratio which persisted into the chronic phase. These observations underscore the functional involvement of CD4 T cells within the CNS during SIV infection, enhancing our understanding of their role in establishing CNS viral presence. Our findings offer insights for potential T cell-focused interventions while underscoring the challenges in eradicating HIV from the CNS, particularly in the context of sub-optimal ART.

Antiretroviral Therapy Intensification for Neurocognitive Impairment in Human Immunodeficiency Virus

BACKGROUND

Neurocognitive impairment (NCI) in people with HIV (PWH) on antiretroviral therapy (ART) is common and may result from persistent HIV replication in the central nervous system.

METHODS

A5324 was a randomized, double-blind, placebo-controlled, 96-week trial of ART intensification with dolutegravir (DTG) + MVC, DTG + Placebo, or Dual - Placebo in PWH with plasma HIV RNA <50 copies/mL on ART and NCI. The primary outcome was the change on the normalized total z score (ie, the mean of individual NC test z scores) at week 48.

RESULTS

Of 357 screened, 191 enrolled: 71% male, 51% Black race, 22% Hispanic ethnicity; mean age 52 years; mean CD4+ T-cells 681 cells/µL. Most (65%) had symptomatic HIV-associated NC disorder. Study drug was discontinued due to an adverse event in 15 (8%) and did not differ between arms (P = .17). Total z score, depressive symptoms, and daily functioning improved over time in all arms with no significant differences between them at week 48 or later. Adjusting for age, sex, race, study site, efavirenz use, or baseline z score did not alter the results. Body mass index modestly increased over 96 weeks (mean increase 0.32 kg/m2, P = .006) and did not differ between arms (P > .10).

CONCLUSIONS

This is the largest, randomized, placebo-controlled trial of ART intensification for NCI in PWH. The findings do not support empiric ART intensification as a treatment for NCI in PWH on suppressive ART. They also do not support that DTG adversely affects cognition, mood, or weight.

CD4 T cell Responses in the CNS during SIV infection

Virologic suppression with antiretroviral therapy (ART) has significantly improved health outcomes for people living with HIV, yet challenges related to chronic inflammation in the central nervous system (CNS) - known as Neuro-HIV- persist. As primary targets for HIV-1 with the ability to survey and populate the CNS and interact with myeloid cells to co-ordinate neuroinflammation, CD4 T cells are pivotal in Neuro-HIV. Despite their importance, our understanding of CD4 T cell distribution in virus-targeted CNS tissues, their response to infection, and potential recovery following initiation of ART remain limited. To address these gaps, we studied ten SIVmac251-infected rhesus macaques using an ART regimen simulating suboptimal adherence. We evaluated four macaques during the acute phase pre-ART and six during the chronic phase. Our data revealed that HIV target CCR5+ CD4 T cells inhabit both the brain parenchyma and adjacent CNS tissues, encompassing choroid plexus stroma, dura mater, and the skull bone marrow. Aligning with the known susceptibility of CCR5+ CD4 T cells to viral infection and their presence within the CNS, high levels of viral RNA were detected in the brain parenchyma and its border tissues during acute SIV infection. Single-cell RNA sequencing of CD45+ cells from the brain revealed colocalization of viral transcripts within CD4 clusters and significant activation of antiviral molecules and specific effector programs within T cells, indicating CNS CD4 T cell engagement during infection. Despite viral suppression with ART, acute infection led to significant depletion of CNS CD4 T cells, persisting into the chronic phase. These findings underscore the functional involvement of CD4 T cells within the CNS during SIV infection, enhancing our understanding of their role in establishing CNS viral presence. Our results offer insights for potential T cell-focused interventions while also underscoring the challenges in eradicating HIV from the CNS, even with effective ART.

Association of combination antiretroviral therapy with risk of neurological diseases in patients with HIV/AIDS in Taiwan: a nested case-control study

Heterogeneous neurocognitive impairment remains an important issue, even in the era of combination antiretroviral therapy (cART), with an incidence ranging from 15% to 65%. Although ART drugs with higher penetration scores to the central nervous system (CNS) show better HIV replication control in the CNS, the association between CNS penetration effectiveness (CPE) scores and neurocognitive impairment remains inconclusive. To explore whether ART exposure is associated with the risk of neurological diseases among patients with HIV/AIDS, this study in Taiwan involved 2,571 patients with neurological diseases and 10,284 matched, randomly selected patients without neurological diseases between 2010 and 2017. A conditional logistic regression model was used in this study. The parameters for ART exposure included ART usage, timing of exposure, cumulative defined daily dose (DDD), adherence, and cumulative CPE score. Incident cases of neurological diseases, including CNS infections, cognitive disorders, vasculopathy, and peripheral neuropathy, were obtained from the National Health Insurance Research Database in Taiwan. Odds ratios (ORs) for the risk of neurological diseases were conducted using a multivariate conditional logistic regression model. Patients with a history of past exposure (OR: 1.68, 95% confidence interval [CI]:1.22-2.32), low cumulative DDDs (< 2,500) (OR: 1.28, 95% CI: 1.15-1.42), low adherence (0 < adherence (ADH) ≤ 0.8) (OR: 1.46, 95% CI: 1.30-1.64), or high cumulative CPE scores (>14) (OR: 1.34, 95% CI: 1.14-1.57) had a high risk of neurological diseases. When stratified by classes of ART drugs, patients with low cumulative DDDs or low adherence had a high risk of neurological diseases, including NRTIs, PIs, NNRTIs, INSTIs, and multi-drug tablets. Subgroup analyses also suggested that patients with low cumulative DDDs or low adherence had a high risk of neurological diseases when they had high cumulative CPE scores. Patients with high cumulative DDDs or medication adherence were protected against neurological diseases only when they had low cumulative CPE scores (≤ 14). Patients may be at risk for neurological diseases when they have low cumulative DDDs, low adherence, or usage with high cumulative CPE scores. Continuous usage and low cumulative CPE scores of ART drugs may benefit neurocognitive health in patients with HIV/AIDS.

In Utero Antiretroviral Exposure and Risk of Neurodevelopmental Problems in HIV-Exposed Uninfected 5-Year-Old Children

Studies have observed neurodevelopmental (ND) challenges among young children perinatally HIV-exposed yet uninfected (CHEU) with in utero antiretroviral (ARV) exposure, without clear linkage to specific ARVs. Atazanavir (ATV) boosted with ritonavir has been a preferred protease inhibitor recommended for pregnant women, yet associations of ATV with ND problems in CHEU have been reported. Studies among early school-age children are lacking. The pediatric HIV/AIDS cohort study (PHACS) surveillance monitoring for antiretroviral therapy (ART) toxicities (SMARTT) study evaluated 5-year-old monolingual English-speaking CHEU using the behavior assessment system for children, Wechsler preschool and primary scales of intelligence, and test of language development-primary. A score ≥1.5 standard deviations worse than population norms defined a signal within each domain. Analyses of risk for signals were stratified by timing of any ARV initiation. Associations between ARV exposure and risk of ND signals were assessed using proportional odds models, adjusting for confounders. Among 230 children exposed to ARVs at conception, 15% had single and 8% had multiple ND problems; ATV exposure was not associated with higher risk of signals [adjusted cumulative odds ratio (cOR) = 0.66, confidence interval (CI): 0.28-1.56]. However, among 461 children whose mothers initiated ARVs during pregnancy, 21% had single and 12% had multiple ND problems; ATV exposure was associated with higher risk of signals (cOR = 1.70, CI: 0.82-3.54). The specific regimen tenofovir/emtricitabine/ATV was associated with higher risk (cOR = 2.31, CI: 1.08-4.97) relative to regimens using a zidovudine/lamivudine backbone combined with non-ATV ARVs. It remains important to monitor neurodevelopment of CHEU during early childhood and investigate the impact and the role of timing of in utero exposure to specific ARVs.

HIV-Associated Dementia: Associated Factors and Characteristics of Cognitive Domain Abnormalities in Elderly People Living with HIV Treated with Highly Active Antiretroviral Therapy

This study aimed to evaluate the prevalence and associated factors of HIV-associated dementia (HAD) in people living with HIV (PLWH) aged ≥ 60 years who are currently treated with highly active antiretroviral therapy. A cross-sectional study was conducted on adult (age ≥ 60 years) PLWH at the infectious clinic, Vajira Hospital, Navamindradhiraj University, Thailand, between August 2019 and March 2021. We collected the patients' characteristics and performed Montreal Cognitive Assessment and Instrumental Activities of Daily Living test to determine whether they have HIV-associated neurocognitive disorders (HAND), which we further classified into asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), and HAD. Finally, we evaluated the prevalence, associated factors, and characteristics of cognitive domain abnormalities in these patients. We enrolled 84 elderly PLWH patients consisting of 43 (51.2%) males. The mean patient age was 63 years (SD ± 3.9), and the median duration of HIV infection was 13 (SD ± 5.7) years. All the patients had undetectable HIV viral load. Among them, seven (8.3%) had no neurocognitive impairment, 61 (72.6%) had ANI, three (3.6%) had MND, and 13 (15.5%) had HAD. After confounder adjustment, the patient age of ≥ 65 years was found to be significantly associated with dementia (odds ratio = 5.97, 95% CI: 1.51-23.57). Significant difference in the mean score of all cognitive domains was observed between the patients with HAD and those with normal cognitive status. HAND is common in PLWH. Age older than ≥ 65 years is a risk factor of HAD.

Nanodelivery of antiretroviral drugs to nervous tissues

Despite the development of effective combined antiretroviral therapy (cART), the neurocognitive impairments associated with human immunodeficiency virus (HIV) remain challenging. The presence of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCFB) impedes the adequate penetration of certain antiretroviral drugs into the brain. In addition, reports have shown that some antiretroviral drugs cause neurotoxicity resulting from their interaction with nervous tissues due to long-term systemic exposure. Therefore, the research into the effective therapeutic modality that would cater for the HIV-associated neurocognitive disorders (HAND) and ART toxicity is now receiving broad research attention. Thus, this review explores the latest information in managing HAND using a nanoparticle drug delivery system (NDDS). We discussed the neurotoxicity profile of various approved ART. Also, we explained the applications of silver nanoparticles (AgNPs) in medicine, their different synthesis methods and their interaction with nervous tissues. Lastly, while proposing AgNPs as useful nanoparticles in properly delivering ART to enhance effectiveness and minimize neurocognitive disorders, we hypothesize that the perceived toxicity of AgNPs could be minimized by taking appropriate precautions. One such precaution is using appropriate reducing and stabilizing agents such as trisodium citrate to reduce silver ion Ag + to ground state Ag0 during the synthesis. Also, the usage of medium-sized, spherical-shaped AgNPs is encouraged in AgNPs-based drug delivery to the brain due to their ability to deliver therapeutic agents across BBB. In addition, characterization and functionalization of the synthesized AgNPs are required during the drug delivery approach. Putting all these factors in place would minimize toxicity and enhance the usage of AgNPs in delivering therapeutic agents across the BBB to the targeted brain tissue and could cater for the HIV-associated neurocognitive disorders and neurotoxic effects of antiretroviral drugs (ARDs).

Neuropathogenesis of HIV and emerging therapeutic targets

INTRODUCTION

HIV infection causes a wide range of neurological complications, many of which are among the most common complications of chronic HIV infection in the era of combined antiretroviral therapy. These neurological conditions arise due to complex interactions between HIV viral proteins and neuronal and glial cells that lead to the activation of various inflammatory and neurotoxic pathways across the nervous system.

AREAS COVERED

This review summarizes the current literature on the pathogenesis and clinical manifestations of neurological injuries associated with HIV in the brain, spinal cord, and peripheral nervous system. Molecular pathways relevant for possible therapeutic targets or advancements are emphasized. Gaps in knowledge and current challenges in therapeutic design are also discussed.

EXPERT OPINION

Several challenges exist in the development of therapeutic targets for HIV-associated cognitive impairments. However, recent developments in drug delivery systems and treatment strategies are encouraging. Treatments for HIV-associated pain and peripheral sensory neuropathies currently consist of symptomatic management, but a greater understanding of their pathogenesis can lead to the development of targeted molecular therapies and disease-modifying therapies. HIV-associated autonomic dysfunction may affect the course of systemic disease via disrupted neuro-immune interactions; however, more research is needed to facilitate our understanding of how these processes present clinically.

HIV Antiretroviral Medication Neuropenetrance and Neurocognitive Outcomes in HIV+ Adults: A Review of the Literature Examining the Central Nervous System Penetration Effectiveness Score

This literature review summarizes the existing research examining the CNS penetration effectiveness (CPE) score and neurocognitive outcomes (i.e., neuropsychological assessment and neurocognitive screening) in HIV+ individuals. Despite the effectiveness of Combined Antiretroviral Therapy (CART) in reducing mortality and morbidity in HIV and controlling viral replication, HIV often persists in the Central Nervous System (CNS), and rates of neurocognitive impairment remain higher than predicted in the post-CART era. The CPE score was developed to rank antiretroviral regimens on their ability to penetrate the CNS and potency in inhibiting the virus, and it has been examined in relation to neurocognitive functioning for over a decade. Based on the results of 23 studies, we conclude that CPE is not as strongly associated with neurocognitive outcomes as initially hypothesized, although higher CPE ARV regimens may be associated with modest, improved outcomes in global neurocognitive functioning, and to a lesser extent attention/working memory and learning/memory. Conclusions, however, are limited by the heterogeneity in study design and methods, and the lack of a more recent CPE metric update. It is recommended that future research in this area employ comprehensive, standardized neuropsychological test batteries and examine domain-level performance, and use the newer 2010 CPE metric, although an updated CPE ranking is urgently needed.

Anti-HIV Drugs Cause Mitochondrial Dysfunction in Monocyte-Derived Macrophages

Combination antiretroviral therapy (cART) dramatically changed the face of the HIV/AIDS pandemic, making it one of the most prominent medical breakthroughs of the past 3 decades. However, as the life span of persons living with HIV (PLWH) continues to approach that of the general population, the same cannot be said regarding their quality of life. PLWH are affected by comorbid conditions such as high blood pressure, diabetes, and neurocognitive impairment at a higher rate and increased severity than their age-matched counterparts. PLWH also have higher levels of inflammation, the drivers of which are not entirely clear. As cART treatment is lifelong, we assessed here the effects of cART, independent of HIV, on primary human monocyte-derived macrophages (MDMs). MDMs were unskewed or skewed to an alternative phenotype and treated with Atripla or Triumeq, two first-line cART treatments. We report that Triumeq skewed alternative MDMs toward an inflammatory nonsenescent phenotype. Both Atripla and Triumeq caused mitochondrial dysfunction, specifically efavirenz and abacavir. Additionally, transcriptome sequencing (RNA-seq) demonstrated that both Atripla and Triumeq caused differential regulation of genes involved in immune regulation and cell cycle and DNA repair. Collectively, our data demonstrate that cART, independent of HIV, alters the MDM phenotype. This suggests that cART may contribute to cell dysregulation in PLWH that subsequently results in increased susceptibility to comorbidities.

Multimodal Investigation of Neuroinflammation in Aviremic Patients With HIV on Antiretroviral Therapy and HIV Elite Controllers

BACKGROUND AND OBJECTIVES

The presence of HIV in the CNS has been related to chronic immune activation and cognitive dysfunction. The aim of this work was to investigate (1) the presence of neuroinflammation in aviremic people with HIV (PWH) on therapy and in nontreated aviremic PWH (elite controllers [ECs]) using a translocator protein 18 kDa radioligand; (2) the relationship between neuroinflammation and cognitive function in aviremic PWH; and (3) the relationship between [¹¹C]-PBR28 signal and quantitative MRI (qMRI) measures of brain tissue integrity such as T1 and T2 relaxation times (rts).

METHODS

[¹¹C]-PBR28 (standard uptake value ratio, SUVR) images were generated in 36 participants (14 PWH, 6 ECs, and 16 healthy controls) using a statistically defined pseudoreference region. Group comparisons of [¹¹C]-PBR28 SUVR were performed using region of interest-based and voxelwise analyses. The relationship between inflammation, qMRI measures, and cognitive function was studied.

RESULTS

In region of interest analyses, ECs exhibited significantly lower [¹¹C]-PBR28 signal in the thalamus, putamen, superior temporal gyrus, prefrontal cortex, and cerebellum compared with the PWH. In voxelwise analyses, differences were observed in the thalamus, precuneus cortex, inferior temporal gyrus, occipital cortex, cerebellum, and white matter (WM). [¹¹C]-PBR28 signal in the WM and superior temporal gyrus was related to processing speed and selective attention in PWH. In a subset of PWH (n = 12), [¹¹C]-PBR28 signal in the thalamus and WM regions was related to a decrease in T2 rt and to an increase in T1 rt suggesting a colocalization of increased glial metabolism, decrease in microstructural integrity, and iron accumulation.

DISCUSSION

This study casts a new light onto the role of neuroinflammation and related microstructural alterations of HIV infection in the CNS and shows that ECs suppress neuroinflammation more effectively than PWH on therapy.

Chemical exchange saturation transfer for detection of antiretroviral drugs in brain tissue

OBJECTIVE

Antiretroviral drug theranostics facilitates the monitoring of biodistribution and efficacy of therapies designed to target HIV type-1 (HIV-1) reservoirs. To this end, we have now deployed intrinsic drug chemical exchange saturation transfer (CEST) contrasts to detect antiretroviral drugs within the central nervous system (CNS).

DESIGN AND METHODS

CEST effects for lamivudine (3TC) and emtricitabine (FTC) were measured by asymmetric magnetization transfer ratio analyses. The biodistribution of 3TC in different brain sub-regions of C57BL/6 mice treated with lipopolysaccharides was determined using MRI. CEST effects of 3TC protons were quantitated by Lorentzian fitting analysis. 3TC levels in plasma and brain regions were measured using ultraperformance liquid chromatography tandem mass spectrometry to affirm the CEST test results.

RESULTS

CEST effects of the hydroxyl and amino protons in 3TC and FTC linearly correlated to drug concentrations. 3TC was successfully detected in vivo in brain sub-regions by MRI. The imaging results were validated by measurements of CNS drug concentrations.

CONCLUSION

CEST contrasts can be used to detect antiretroviral drugs using MRI. Such detection can be used to assess spatial--temporal drug biodistribution. This is most notable within the CNS where drug biodistribution may be more limited with the final goal of better understanding antiretroviral drug-associated efficacy and potential toxicity.

HIV Associated Neurocognitive Disorders Subsidence Through Citalopram Addition in Anti-retroviral Therapy (HANDS-CARE): A Concept Note

There is a pressing need to effectively manage HIV Associated Neurocognitive Disorders (HAND) in sub-Saharan Africa (SSA) where the burden is among the highest in the world. Contemporary approaches based on the use of Highly Active Antiretroviral Therapy (HAART) alone are inadequate interventions for HAND, especially in SSA where there is limited availability of the required combinations of HAART for effective central nervous system penetration and where many currently prescribed agents, including efavirenz, have neurotoxicity as a major drawback. This article reviews data supporting the rationale for additive citalopram in antiretroviral therapy as a latent approach to abate HAND. It proposes the conduct of a HIV Associated Neurocognitive Disorders Subsidence through Citalopram addition in Anti-Retroviral therapy (HANDS-CARE) pilot feasibility trial (RCT) to assess whether the adjunctive use of citalopram, a widely prescribed serotonergic antidepressant, will lead to a meaningful improvement in neurocognitive functioning and quality of life in patients with HAND who are receiving HAART. A preliminarily feasible and efficacy-suggesting HANDS-CARE trial could generate statistical, clinical and operational data necessary to design and conduct a future definitive RCT. If successful, this intervention will be applicable to resource-limited settings as well as developed countries. Effective management of HAND will improve the quality of life of HIV patients, and reduce the cost of managing the disease.

Interrogating the impact of combination antiretroviral therapies on HIV-associated neurocognitive disorders

OBJECTIVES

Although the advent of Combination Antiretroviral Therapy (cART) has greatly reduced the prevalence of HIV-Associated Dementia, the most severe form of HIV-Associated Neurocognitive Disorder (HAND), the incidence of the milder forms of HAND have risen. The explanations proposed include persistent central nervous system (CNS) viraemia and the neurotoxicity of chronic cART regimens. Nonetheless, controversies in HAND prevalence estimates, alongside a lack of consensus on the significance of CNS Penetration Effectiveness (CPE) have added to the complexity of elucidating the role of cART in HAND. The present review will evaluate the evidence underlying these explanations, as well as highlighting the need for improved trial designs and the incorporation of emerging biomarkers and neuroimaging tools.

METHODS

A review of the current literature investigating cART neurotoxicity, controversies in HAND prevalence estimates, CNS Penetration Effectiveness, and neuroprotective adjuvant therapies.

CONCLUSIONS

Ultimately, the inadequacy of cART in achieving complete preservation of the CNS underscores the imminent need for neuroprotective adjuvant therapies, where the efficacy of combining multiple adjuvant classes presents a potential therapeutic frontier which must be interrogated.

Antiretroviral therapy administration reduces neuroinflammation without restoring brain-derived neurotrophic factor signaling in alcohol-administered simian immunodeficiency virus-infected macaques

OBJECTIVE

The present study examined interactions between simian immunodeficiency virus (SIV), chronic binge alcohol (CBA), and antiretroviral therapy (ART) on growth factor signaling, neuroinflammatory markers, viral loads (VL), and CD4+ cell counts.

DESIGN

Adult male rhesus macaques were administered CBA (13-14 g ethanol (EtOH)/kg per week) or sucrose (SUC) 3 months prior to SIVmac251 infection until the study endpoint. At viral setpoint, a subset of CBA/SIV+ and SUC/SIV+ macaques were randomized to receive daily ART (9-[2-Phosphonyl-methoxypropyly]adenine [PMPA] 20 mg/kg, 2',3'-dideoxy-5-fluoro-3'-thiacytidine (FTC), 30 mg/kg). Frontal cortex (FC) and basal ganglia (BG) were collected for gene and protein expression.

METHODS

Relationships between brain and plasma VL or CD4+ cell counts were determined using linear regression. Effects of SIV, CBA, and ART on markers of neuroinflammation and brain-derived neurotrophic factor (BDNF) signaling were determined by ANOVA and linear regression.

RESULTS

SIV increased FC and BG neuroinflammatory and glial cell gene expression (CX3CR1, B2M), and reduced FC protein kinase B phosphorylation. CBA decreased FC and BG tropomyosin receptor kinase B (TrkB) phosphorylation, and increased full-length TrkB (TrkB-FL) and SLC1A3 expression in FC and BG, respectively. ART suppressed plasma and brain VL, reduced neuroinflammatory gene expression in FC (IBA1, CX3CR1, and GFAP), and BG (CD74 and CD11ß), and did not restore FC or BG BDNF signaling deficits.

CONCLUSIONS

Results show ART-mediated reduction in VL and neuroinflammatory gene expression, irrespective of CBA administration. ART did not attenuate SIV- and CBA-mediated BDNF signaling deficits, suggesting these deficits, despite effective neuroinflammation suppression, may explain CBA- and SIV-associated neurocognitive deficits. Therapeutics targeting growth factor signaling may be important adjuvants in treating HIV-associated neurocognitive decline.

Non-human Primate Models to Investigate Mechanisms of Infection-Associated Fetal and Pediatric Injury, Teratogenesis and Stillbirth

A wide array of pathogens has the potential to injure the fetus and induce teratogenesis, the process by which mutations in fetal somatic cells lead to congenital malformations. Rubella virus was the first infectious disease to be linked to congenital malformations due to an infection in pregnancy, which can include congenital cataracts, microcephaly, hearing impairment and congenital heart disease. Currently, human cytomegalovirus (HCMV) is the leading infectious cause of congenital malformations globally, affecting 1 in every 200 infants. However, our knowledge of teratogenic viruses and pathogens is far from complete. New emerging infectious diseases may induce teratogenesis, similar to Zika virus (ZIKV) that caused a global pandemic in 2016-2017; thousands of neonates were born with congenital microcephaly due to ZIKV exposure in utero, which also included a spectrum of injuries to the brain, eyes and spinal cord. In addition to congenital anomalies, permanent injury to fetal and neonatal organs, preterm birth, stillbirth and spontaneous abortion are known consequences of a broader group of infectious diseases including group B streptococcus (GBS), Listeria monocytogenes, Influenza A virus (IAV), and Human Immunodeficiency Virus (HIV). Animal models are crucial for determining the mechanism of how these various infectious diseases induce teratogenesis or organ injury, as well as testing novel therapeutics for fetal or neonatal protection. Other mammalian models differ in many respects from human pregnancy including placentation, labor physiology, reproductive tract anatomy, timeline of fetal development and reproductive toxicology. In contrast, non-human primates (NHP) most closely resemble human pregnancy and exhibit key similarities that make them ideal for research to discover the mechanisms of injury and for testing vaccines and therapeutics to prevent teratogenesis, fetal and neonatal injury and adverse pregnancy outcomes (e.g., stillbirth or spontaneous abortion). In this review, we emphasize key contributions of the NHP model pre-clinical research for ZIKV, HCMV, HIV, IAV, L. monocytogenes, Ureaplasma species, and GBS. This work represents the foundation for development and testing of preventative and therapeutic strategies to inhibit infectious injury of human fetuses and neonates.

Beneficial and Adverse Effects of cART Affect Neurocognitive Function in HIV-1 Infection: Balancing Viral Suppression against Neuronal Stress and Injury

HIV-associated neurocognitive disorders (HAND) persist despite the successful introduction of combination antiretroviral therapy (cART). While insufficient concentration of certain antiretrovirals (ARV) may lead to incomplete viral suppression in the brain, many ARVs are found to cause neuropsychiatric adverse effects, indicating their penetration into the central nervous system (CNS). Several lines of evidence suggest shared critical roles of oxidative and endoplasmic reticulum stress, compromised neuronal energy homeostasis, and autophagy in the promotion of neuronal dysfunction associated with both HIV-1 infection and long-term cART or ARV use. As the lifespans of HIV patients are increased, unique challenges have surfaced. Longer lives convey prolonged exposure of the CNS to viral toxins, neurotoxic ARVs, polypharmacy with prescribed or illicit drug use, and age-related diseases. All of these factors can contribute to increased risks for the development of neuropsychiatric conditions and cognitive impairment, which can significantly impact patient well-being, cART adherence, and overall health outcome. Strategies to increase the penetration of cART into the brain to lower viral toxicity may detrimentally increase ARV neurotoxicity and neuropsychiatric adverse effects. As clinicians attempt to control peripheral viremia in an aging population of HIV-infected patients, they must navigate an increasingly complex myriad of comorbidities, pharmacogenetics, drug-drug interactions, and psychiatric and cognitive dysfunction. Here we review in comparison to the neuropathological effects of HIV-1 the available information on neuropsychiatric adverse effects and neurotoxicity of clinically used ARV and cART. It appears altogether that future cART aiming at controlling HIV-1 in the CNS and preventing HAND will require an intricate balancing act of suppressing viral replication while minimizing neurotoxicity, impairment of neurocognition, and neuropsychiatric adverse effects. Graphical abstract Schematic summary of the effects exerted on the brain and neurocognitive function by HIV-1 infection, comorbidities, psychostimulatory, illicit drugs, therapeutic drugs, such as antiretrovirals, the resulting polypharmacy and aging, as well as the potential interactions of all these factors.

Treating viruses in the brain: Perspectives from NeuroAIDS

Aggressive use of antiretroviral therapy has led to excellent viral suppression within the systemic circulation. However, despite these advances, HIV reservoirs still persist. The persistence of HIV within the brain can lead to the development of HIV-associated neurocognitive disorders (HAND). Although the causes of the development of neurocognitive disorders is likely multifactorial, the inability of antiretroviral therapy to achieve adequate concentrations within the brain is likely a major contributing factor. Information about antiretroviral drug exposure within the brain is limited. Clinically, drug concentrations within the cerebrospinal fluid (CSF) are used as markers for central nervous system (CNS) drug exposure. However, significant differences exist; CSF concentration is often a poor predictor of drug exposure within the brain. This article reviews the current information regarding antiretroviral exposure within the brain in humans as well as preclinical animals and discusses the impact of co-morbidities on antiretroviral efficacy within the brain. A more thorough understanding of antiretroviral penetration into the brain is an essential component to the development of better therapeutic strategies for neuroAIDS.

Neuroimaging Advances in Diagnosis and Differentiation of HIV, Comorbidities, and Aging in the cART Era

In the "cART era" of more widely available and accessible treatment, aging and HIV-related comorbidities, including symptoms of brain dysfunction, remain common among HIV-infected individuals on suppressive treatment. A better understanding of the neurobiological consequences of HIV infection is essential for developing thorough treatment guidelines and for optimizing long-term neuropsychological outcomes and overall brain health. In this chapter, we first summarize magnetic resonance imaging (MRI) methods used in over two decades of neuroHIV research. These methods evaluate brain volumetric differences and circuitry disruptions in adults living with HIV, and help map clinical correlations with brain function and tissue microstructure. We then introduce and discuss aging and associated neurological complications in people living with HIV, and processes by which infection may contribute to the risk for late-onset dementias. We describe how new technologies and large-scale international collaborations are helping to disentangle the effect of genetic and environmental risk factors on brain aging and neurodegenerative diseases. We provide insights into how these advances, which are now at the forefront of Alzheimer's disease research, may advance the field of neuroHIV. We conclude with a summary of how we see the field of neuroHIV research advancing in the decades to come and highlight potential clinical implications.

CSF HIV RNA Escape in Opsoclonus-Myoclonus-Ataxia Syndrome: Case Report and Review of the Literature

Background: Human immunodeficiency viruses (HIV) infection is associated with a broad range of neurological manifestations, including opsoclonus-myoclonus ataxia syndrome (OMAS) occurring in primary infection, immune reconstitution syndrome or in case of opportunistic co-infection.

Case: We report the exceptional case of a 43-year-old female under HIV treatment for 10 years who presented initially with suspected epileptic seizure. Although the clinical picture slightly improved under anti-epileptic treatment, it was rapidly attributed to OMAS. The patient exhibited marked opsoclonus, mild dysarthria, upper limbs intermittent myoclonus, ataxia in 4 limbs, truncal ataxia, and a severe gait ataxia (SARA score: 34). The diagnostic work-up showed radiological and biological signs of central nervous system (CNS) inflammation and cerebral venous sinus thromboses. The HIV viral load was higher in cerebrospinal fluid (CSF) than in the blood (4,560 copies/ml vs. 76 copies/ml). She was treated for 5 days with pulsed corticotherapy. Dolutegravir and anticoagulation administration were initiated. Follow-ups at 2 and 4 months showed a dramatic improvement of clinical neurologic status (SARA score at 4 months: 1), reduction of CNS inflammation and revealed undetectable CSF and serum viral loads.

Conclusion: This case underlines the importance of the evaluation of the CSF viral load in HIV patients developing OMAS and suggests CSF HIV RNA escape as a novel cause for OMAS.

Changes in neurocognitive assessment scores after initiating dolutegravir- versus elvitegravir-based antiretroviral therapy

This prospective cohort study enrolled people living with HIV initiating antiretroviral therapy (ART) containing the integrase inhibitors, dolutegravir (DTG) or elvitegravir (EVG) and administered the Montreal Cognitive Assessment (MoCA) at baseline and again after approximately six months to compare changes in MoCA scores. The proportion of patients found to have cognitive impairment, as indicated by a MoCA score <26/30, on each agent were also compared and comparisons were made between changes in each domain assessed by the MoCA (visuospatial/executive, naming, attention, language, abstraction, delayed recall, and orientation). Thirty-five evaluable participants were enrolled, 18 on DTG and 17 on EVG. The median [interquartile range(IQR)] age was 44 (32 to 54) years, 63% were male, 57% were African American. The median (IQR) MoCA score at baseline was 25 (23 to 27) with no difference between groups (p=0.249). The median (IQR) change in MoCA score was 0 (-1 to 2) for DTG and 1 (0 to 3) for EVG (p = 0.183). Of those on DTG, 8 (44%) had MoCA scores <26 on follow-up compared to 11 (65%) on EVG (p = 0.229). There were no significant differences in changes in any of the individual MoCA domains.

Potential pharmacological approaches for the treatment of HIV-1 associated neurocognitive disorders

HIV associated neurocognitive disorders (HAND) are the spectrum of cognitive impairments present in patients infected with human immunodeficiency virus type 1 (HIV-1). The number of patients affected with HAND ranges from 30 to 50% of HIV infected individuals and although the development of combinational antiretroviral therapy (cART) has improved longevity, HAND continues to pose a significant clinical problem as the current standard of care does not alleviate or prevent HAND symptoms. At present, the pathological mechanisms contributing to HAND remain unclear, but evidence suggests that it stems from neuronal injury due to chronic release of neurotoxins, chemokines, viral proteins, and proinflammatory cytokines secreted by HIV-1 activated microglia, macrophages and astrocytes in the central nervous system (CNS). Furthermore, the blood-brain barrier (BBB) not only serves as a route for HIV-1 entry into the brain but also prevents cART therapy from reaching HIV-1 brain reservoirs, and therefore could play an important role in HAND. The goal of this review is to discuss the current data on the epidemiology, pathology and research models of HAND as well as address the potential pharmacological treatment approaches that are being investigated.

New Potential Axes of HIV Neuropathogenesis with Relevance to Biomarkers and Treatment

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) affect approximately half of people living with HIV despite viral suppression with antiretroviral therapies and represent a major cause of morbidity. HAND affects activities of daily living including driving, using the Internet and, importantly, maintaining drug adherence. Whilst viral suppression with antiretroviral therapies (ART) has reduced the incidence of severe dementia, mild neurocognitive impairments continue to remain prevalent. The neuropathogenesis of HAND in the context of viral suppression remains ill-defined, but underlying neuroinflammation is likely central and driven by a combination of chronic intermittent low-level replication of whole virus or viral components, latent HIV infection, peripheral inflammation possibly from a disturbed gut microbiome or chronic cellular dysfunction in the central nervous system. HAND is optimally diagnosed by clinical assessment with imaging and neuropsychological testing, which can be difficult to perform in resource-limited settings. Thus, the identification of biomarkers of disease is a key focus of the field. In this chapter, recent advances in the pathogenesis of HAND and biomarkers that may aid its diagnosis and treatment will be discussed.

The Role of Brain Derived Neurotrophic Factor in HIV-Associated Neurocognitive Disorder: From the Bench-Top to the Bedside

Human immunodeficiency virus (HIV)-associated neurocognitive disorder (HAND) remains prevalent in the anti-retroviral (ART) era. While there is a complex interplay of many factors in the neuropathogenesis of HAND, decreased neurotrophic synthesis has been shown to contribute to synaptic degeneration which is a hallmark of HAND neuropathology. Brain derived neurotrophic factor (BDNF) is the most abundant and synaptic-promoting neurotrophic factor in the brain and plays a critical role in both learning and memory. Reduced BDNF levels can worsen neurocognitive impairment in HIV-positive individuals across several domains. In this paper, we review the evidence from pre-clinical and clinical studies showing the neuroprotective roles of BDNF against viral proteins, effect on co-morbid mental health disorders, altered human microbiome and ART in HAND management. Potential applications of BDNF modulation in pharmacotherapeutic, cognitive and behavioral interventions in HAND are also discussed. Finally, research gaps and future research direction are identified with the aim of helping researchers to direct efforts to make these BDNF driven interventions improve the quality of life of patients living with HAND.

Clinical Treatment Options and Randomized Clinical Trials for Neurocognitive Complications of HIV Infection: Combination Antiretroviral Therapy, Central Nervous System Penetration Effectiveness, and Adjuvants

The etiology and pathogenesis of human immunodeficiency virus type-I (HIV)-associated neurocognitive disorders (HAND) remain undetermined and are likely the produce of multiple mechanisms. This can mainly include neuronal injury from HIV, inflammatory processes, and mental health issues. As a result, a variety of treatment options have been tested including NeuroHIV-targeted regimens based on the central nervous system (CNS) penetration effectiveness (CPE) of antiretroviral therapy (ART) and adjuvant therapies for HAND. NeuroHIV-targeted ART regimens have produced consistent and statistically significant HIV suppression in the CNS, but this is not the case for cognitive and functional domains. Most adjuvant therapies such as minocycline, memantine, and selegiline have negligible benefit in the improvement of cognitive function of people living with HIV (PLWH) with mild to moderate neurocognitive impairment. Newer experimental treatments have been proposed to target cognitive and functional symptoms of HAND as well as potential underlying pathogenesis. This review aims to provide an analytical overview of the clinical treatment options and clinical trials for HAND by focusing on NeuroHIV-targeted ART regimen development, CPE, and adjuvant therapies.

Machine learning models reveal neurocognitive impairment type and prevalence are associated with distinct variables in HIV/AIDS

Neurocognitive impairment (NCI) among HIV-infected patients is heterogeneous in its reported presentations and frequencies. To determine the prevalence of NCI and its associated subtypes as well as predictive variables, we investigated patients with HIV/AIDS receiving universal health care. Recruited adult HIV-infected subjects underwent a neuropsychological (NP) test battery with established normative (sex-, age-, and education-matched) values together with assessment of their demographic and clinical variables. Three patient groups were identified including neurocognitively normal (NN, n = 246), HIV-associated neurocognitive disorders (HAND, n = 78), and neurocognitively impaired-other disorders (NCI-OD, n = 46). Univariate, multiple logistic regression and machine learning analyses were applied. Univariate analyses showed variables differed significantly between groups including birth continent, quality of life, substance use, and PHQ-9. Multiple logistic regression models revealed groups again differed significantly for substance use, PHQ-9 score, VACS index, and head injury. Random forest (RF) models disclosed that classification algorithms distinguished HAND from NN and NCI-OD from NN with area under the curve (AUC) values of 0.87 and 0.77, respectively. Relative importance plots derived from the RF model exhibited distinct variable rankings that were predictive of NCI status for both NN versus HAND and NN versus NCI-OD comparisons. Thus, NCI was frequently detected (33.5%) although HAND prevalence (21%) was lower than in several earlier reports underscoring the potential contribution of other factors to NCI. Machine learning models uncovered variables related to individual NCI types that were not identified by univariate or multiple logistic regression analyses, highlighting the value of other approaches to understanding NCI in HIV/AIDS.

Evaluating Neurodevelopmental Consequences of Perinatal Exposure to Antiretroviral Drugs: Current Challenges and New Approaches

As antiretroviral therapy (ART) becomes increasingly affordable and accessible to women of childbearing age across the globe, the number of children who are exposed to Human Immunodeficiency Viruses (HIV) but remain uninfected is on the rise, almost all of whom were also exposed to ART perinatally. Although ART has successfully aided in the decline of mother-to-child-transmission of HIV, the long-term effects of in utero exposure to ART on fetal and postnatal neurodevelopment remain unclear. Evaluating the safety and efficacy of therapeutic drugs for pregnant women is a challenge due to the historic limitations on their inclusion in clinical trials and the dynamic physiological states during pregnancy that can alter the pharmacokinetics of drug metabolism and fetal drug exposure. Thus, much of our data on the potential consequences of ART drugs on the developing nervous system comes from preclinical animal models and clinical observational studies. In this review, we will discuss the current state of knowledge and existing approaches to investigate whether ART affects fetal brain development, and describe novel human stem cell-based strategies that may provide additional information to better predict the impact of specific drugs on the human central nervous system. Graphical Abstract Approaches to evaluate the impact of drugs on the developing brain. Dysregulation of the developing nervous system can lead to long-lasting changes. Integration of data from animal models, clinical observations, and cell culture studies is needed to predict the safety of therapeutic antiretroviral drugs during pregnancy. New approaches include human induced pluripotent stem cell (iPSC)-based 2D and 3D models of neuronal networks and brain regions, as well as single cell profiling in response to drug exposure.

Cross-Sectional and Cumulative Longitudinal Central Nervous System Penetration Effectiveness Scores Are Not Associated With Neurocognitive Impairment in a Well Treated Aging Human Immunodeficiency Virus-Positive Population in Switzerland

Background

Neurocognitive impairment (NCI) in people with human immunodeficiency virus (PWH) remains a concern despite potent antiretroviral therapy (ART). Higher central nervous system (CNS) penetration effectiveness (CPE) scores have been associated with better CNS human immunodeficiency virus (HIV) replication control, but the association between CPE and NCI remains controversial.

Methods

The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study is a subgroup of the Swiss HIV Cohort Study (SHCS) that invited patients aged ≥45 years enrolled in the SHCS and followed-up at NAMACO-affiliated centers in Switzerland to participate between May 2013 and November 2016. In total, 981 patients were enrolled, all of whom underwent standardized neurocognitive assessment. Neurocognitive impairment, if present, was characterized using Frascati criteria. The CPE scores of NAMACO study participants with undetectable plasma HIV-ribonucleic acid at enrollment (909 patients) were analyzed. Cross-sectional CPE scores (at neurocognitive assessment) were examined as potential predictors of NCI in multivariate logistic regression models. The analysis was then repeated taking CPE as a cumulative score (summarizing CPE scores from ART initiation to the time of neurocognitive assessment).

Results

Most patients were male (80%) and Caucasian (92%). Neurocognitive impairment was present in 40%: 27% with HIV-associated NCI (mostly asymptomatic neurocognitive impairment), and 13% with NCI related to other factors. None of the CPE scores, neither cross-sectional nor cumulative, was statistically significantly associated with NCI.

Conclusions

In this large cohort of aviremic PWH, we observed no association between NCI, whether HIV-associated or related to other factors, and CPE score, whether cross-sectional or cumulative.

Targeting the HIV-infected brain to improve ischemic stroke outcome

HIV-associated cerebrovascular events remain highly prevalent even in the current era of antiretroviral therapy (ART). We hypothesize that low-level HIV replication and associated inflammation endure despite antiretroviral treatment and affect ischemic stroke severity and outcomes. Using the EcoHIV infection model and the middle cerebral artery occlusion as the ischemic stroke model in mice, we present in vivo analysis of the relationship between HIV and stroke outcome. EcoHIV infection increases infarct size and negatively impacts tissue and functional recovery. Ischemic stroke also results in an increase in EcoHIV presence in the affected regions, suggesting post-stroke reactivation that magnifies pro-inflammatory status. Importantly, ART with a high CNS penetration effectiveness (CPE) is more beneficial than low CPE treatment in limiting tissue injury and accelerating post-stroke recovery. These results provide potential insight for treatment of HIV-infected patients that are at risk of developing cerebrovascular disease, such as ischemic stroke.

No Association Between Human Immunodeficiency Virus Infections And Dementia: A Nationwide Cohort Study In Taiwan

BACKGROUND

The associations between the human immunodeficiency virus (HIV) and dementias are as yet to be studied in Taiwan. The aim of this study is to clarify as to whether HIV infections are associated with the risk of dementia.

METHODS

A total of 1,261 HIV-infected patients and 3,783 controls (1:3) matched for age and sex were selected between January 1 and December 31, 2000 from Taiwan's National Health Insurance Research Database (NHIRD). Fine and Gray's survival analysis (competing with mortality) analyzed the risk of dementias during the 15-year follow up. The association between the highly active antiretroviral therapy (HAART) and dementia was analyzed by stratifying the HAART status among the HIV subjects.

RESULTS

During the follow-up period, 25 in the HIV group (N= 1,261) and 227 in the control group (N= 3,783) developed dementia (656.25 vs 913.15 per 100,000 person-years). Fine and Gray's survival analysis revealed that the HIV patients were not associated with an increased risk of dementia, with the adjusted hazard ratio (HR) as 0.852 (95% confidence interval [CI]: 0.189-2.886, p=0.415) after adjusting for sex, age, comorbidities, geographical region, and the urbanization level of residence. There was no significant difference between the two groups of HIV-infected patients with or without HAART in the risk of dementia.

CONCLUSION

This study found that HIV infections, either with or without HAART, were not associated with increased diagnoses of neurodegenerative dementias in patients older than 50 in Taiwan.

The role of exosomal transport of viral agents in persistent HIV pathogenesis

Human immunodeficiency virus (HIV) infection, despite great advances in antiretroviral therapy, remains a lifelong affliction. Though current treatment regimens can effectively suppress viral load to undetectable levels and preserve healthy immune function, they cannot fully alleviate all symptoms caused by the presence of the virus, such as HIV-associated neurocognitive disorders. Exosomes are small vesicles that transport cellular proteins, RNA, and small molecules between cells as a mechanism of intercellular communication. Recent research has shown that HIV proteins and RNA can be packaged into exosomes and transported between cells, to pathogenic effect. This review summarizes the current knowledge on the diverse mechanisms involved in the sorting of viral elements into exosomes and the damage those exosomal agents can inflict. In addition, potential therapeutic options to counteract exosome-mediated HIV pathogenesis are reviewed and considered.

Impact of Antiretroviral Regimens on Cerebrospinal Fluid Viral Escape in a Prospective Multicohort Study of Antiretroviral Therapy-Experienced Human Immunodeficiency Virus-1-Infected Adults in the United States

Background

Cerebrospinal fluid (CSF) viral escape occurs in 4%-20% of human immunodeficiency virus (HIV)-infected adults, yet the impact of antiretroviral therapy (ART) on CSF escape is unclear.

Methods

A prospective study of 1063 participants with baseline plasma viral load (VL) ≤400 copies/mL between 2005 and 2016. The odds ratio (OR) for ART regimens (protease inhibitor with nucleoside reverse transcriptase inhibitor [PI + NRTI] vs other ART) and CSF escape was estimated using mixed-effects models.

Results

Baseline mean age was 46 years, median plasma VL, and CD4 count were 50 copies/mL, and 424 cells/μL, respectively. During median follow-up of 4.4 years, CSF escape occurred in 77 participants (7.2%). PI + NRTI use was an independent predictor of CSF escape (OR, 3.1; 95% confidence interval, 1.8-5.0) in adjusted analyses and models restricted to plasma VL ≤50 copies/mL (P < .001). Regimens that contained atazanavir (ATV) were a stronger predictor of CSF viral escape than non-ATV PI + NRTI regimens. Plasma and CSF M184V/I combined with thymidine-analog mutations were more frequent in CSF escape vs no escape (23% vs 2.3%). Genotypic susceptibility score-adjusted central nervous system (CNS) penetration-effectiveness (CPE) values were calculated for CSF escape with M184V/I mutations (n = 34). Adjusted CPE values were low (<5) for CSF in 27 (79%), indicating suboptimal CNS drug availability.

Conclusions

PI + NRTI regimens are independent predictors of CSF escape in HIV-infected adults. Reduced CNS ART bioavailability may predispose to CSF escape in patients with M184V/I mutations.

Evaluation of Oral Antiretroviral Drugs in Mice With Metabolic and Neurologic Complications

Antiretroviral (ART) drugs has previously been associated with lipodystrophic syndrome, metabolic consequences, and neuropsychiatric complications. ART drugs include three main classes of protease inhibitors (PIs), nucleoside analog reverse transcriptase inhibitors (NRTIs), and non-nucleoside reverse transcriptase inhibitors (NNRTIs). Our previous work demonstrated that a high risk of hyperlipidemia was observed in HIV-1-infected patients who received ART drugs in Taiwan. Patients receiving ART drugs containing either Abacavir/Lamivudine (Aba/Lam; NRTI/NRTI), Lamivudine/Zidovudine (Lam/Zido; NRTI/NRTI), or Lopinavir/Ritonavir (Lop/Rit; PI) have the highest risk of hyperlipidemia. The aim of this study was to investigate the effects of Aba/Lam (NRTI/NRTI), Lam/Zido (NRTI/NRTI), and Lop/Rit (PI) on metabolic and neurologic functions in mice. Groups of C57BL/6 mice were administered Aba/Lam, Lam/Zido, or Lop/Rit, orally, once daily for a period of 4 weeks. The mice were then extensively tested for metabolic and neurologic parameters. In addition, the effect of Aba/Lam, Lam/Zido, and Lop/Rit on lipid metabolism was assessed in HepG2 hepatocytes and during the 3T3-L1 preadipocyte differentiation. Administration with Aba/Lam caused cognitive and motor impairments in mice, as well as their metabolic imbalances, including alterations in leptin serum levels. Administration with Lop/Rit also caused cognitive and motor impairments in mice, as well as their metabolic imbalances, including alterations in serum levels of total cholesterol, and HDL-c. Treatment of mice with Aba/Lam and Lop/Rit enhanced the lipid accumulation in the liver, and the decrease in AMP-activated protein kinase (AMPK) phosphorylation and/or its downstream target acetyl-CoA carboxylase (ACC) protein expression. In HepG2 hepatocytes, Aba/Lam, Lam/Zido, and Lop/Rit also enhanced the lipid accumulation and decreased phosphorylated AMPK and ACC proteins. In 3T3-L1 pre-adipocyte differentiation, Aba/Lam and Lop/Rit reduced adipogenesis by decreasing expression of transcription factor CEBPb, implicating the lipodystrophic syndrome. Our results demonstrate that daily oral administration of Aba/Lam and Lop/Rit may produce cognitive, motor, and metabolic impairments in mice, regardless of HIV-1 infection.

CSF inflammatory markers and neurocognitive function after addition of maraviroc to monotherapy darunavir/ritonavir in stable HIV patients: the CINAMMON study

CINAMMON is a phase IV, open-label, single-arm, pilot study assessing maraviroc (MVC) in the central nervous system (CNS) when added to darunavir/ritonavir monotherapy (DRV/r) in virologically suppressed HIV-infected subjects. CCR5 tropic participants on DRV/r were recruited. Participants remained on DRV/r for 12 week (w) (control phase). MVC 150 mg qd was added w12-w36 (intervention phase). Lumbar puncture (LP) and neurocognitive function (Cogstate) examinations scheduled at baseline, w12 and w36; MRI before w12, again at w36. Primary endpoint was CSF inflammatory marker changes during intervention phase. Secondary endpoints included changes in NC function and MRI parameters. CSF/plasma DRV/r concentrations measured at w12 and w36, MVC at w36. Nineteen patients recruited, 15 completed (17M, 2F). Dropouts: headache (2), knee problem (could not attend, 1), personal reasons (1). Mean age (range) 45.4 years (27.2-65.1), 13/19 white, 10/19 MSM. No changes in selected CSF markers were seen w12-w36. Overall NC function did not improve w12-w36: total age adjusted z score improved by 0.27 (weighted paired t test; p = 0.11); for executive function only, age adjusted z score improved by 0.54 (p = 0.03). MRI brain parameters unchanged. DRV plasma:CSF concentration ratio unchanged between w12 (132) and w36 (112; p = 0.577, Wilcoxon signed-rank). MVC plasma:CSF concentration ratio was 35 at w36. No changes in neuroinflammatory markers seen. In this small study, addition of 24w MVC 150 mg qd to stable DRV/r monotherapy showed possible improvement in executive function with no global NC effect. Learning effect cannot be excluded. This effect should be further evaluated.

Neuropsychiatric Effects of HIV Antiviral Medications

The development of antiretroviral therapy (ART) has dramatically increased the lifespan of HIV patients but treatment is complicated by numerous adverse effects and toxicities. ART complications include neuropsychiatric, metabolic, gastrointestinal, cardiac, and numerous other toxicities, and clinicians often have to choose one toxicity over another to offer the best medication regimen for a patient. Some antiviral drugs cause significant neuropsychiatric complications, including depression, cognitive impairment, and sleep disturbance. Even in careful studies, it may be difficult to determine which effects are related to the virus, the immune system, or the treatment. Of the six currently marketed classes of antiviral drugs, the nucleoside reverse transcriptase inhibitors and the non-nucleoside reverse transcriptase inhibitors have been most commonly associated with neuropsychiatric complications. Within these classes, certain drugs are more likely to cause difficulty than others. We review the contention regarding the central nervous system (CNS) complications of efavirenz, as well as debate about the role of CNS penetration in drug effectiveness and toxicity. A thorough working knowledge of the neuropsychiatric consequences of ART allows clinicians to tailor treatment more successfully to individual patients as well as to identify ART more quickly as the source of a problem or symptom.

Cognitive trajectories over 4 years among HIV-infected women with optimal viral suppression

OBJECTIVE

To determine whether persistent viral suppression alters cognitive trajectories among HIV-infected (HIV+) women on combination antiretroviral therapy (cART) by investigating performance longitudinally in uninfected (HIV-) and 3 groups of HIV+ women: those with consistent viral suppression after continuous cART use (VS), those without consistent virologic suppression despite continuous cART use (NVS), and those without consistent virologic suppression after intermittent cART use (Int NVS).

METHODS

Two hundred thirty-nine VS, 220 NVS, 172 Int NVS, and 301 HIV- women from the Women's Interagency HIV Study (WIHS) completed neuropsychological testing every 2 years for 3 visits between 2009 and 2013. Mixed-effects regressions were used to examine group differences on continuous T scores and categorical measures of impairment (T score <40).

RESULTS

On global function, VS women demonstrated lower scores and were more likely to score in the impaired range than HIV- women (p = 0.01). These differences persisted over time (group × time, p > 0.39). VS women demonstrated lower learning and memory scores than HIV- women (p < 0.05) and lower attention/working memory and fluency scores than HIV- and NVS women (p < 0.05). Group differences in scores persisted over time. Categorically, VS women were more likely to be impaired on attention/working memory and executive function than HIV- women (p < 0.05). On motor skills, VS and NVS women showed a greater decline and were more likely to be impaired than HIV- women (p < 0.05).

CONCLUSIONS

Cognitive difficulties remain among HIV+ women despite persistent viral suppression. In some instances, VS women are worse than NVS women, reinforcing the need for novel adjunctive therapies to attenuate cognitive problems.

Differential Effects of Antiretroviral Drugs on Neurons In Vitro: Roles for Oxidative Stress and Integrated Stress Response

Mounting evidence suggests that antiretroviral drugs may contribute to the persistence of HIV-associated neurocognitive disorders (HAND), which impact 30%-50% of HIV-infected patients in the post-antiretroviral era. We previously reported that two first generation HIV protease inhibitors, ritonavir and saquinavir, induced oxidative stress, with subsequent neuronal death in vitro, which was reversed by augmentation of the endogenous antioxidant response by monomethyl fumarate. We herein determined whether two newer-generation PIs, darunavir and lopinavir, were deleterious to neurons in vitro. Further, we expanded our assessment to include three integrase strand transfer inhibitors, raltegravir, dolutegravir, and elvitegravir. We found that only lopinavir and elvitegravir were neurotoxic to primary rat neuroglial cultures as determined by the loss of microtubule-associated protein 2 (MAP2). Intriguingly, lopinavir but not elvitegravir led to oxidative stress and induced the endogenous antioxidant response (EAR). Furthermore, neurotoxicity of lopinavir was blocked by pharmacological augmentation of the endogenous antioxidant heme oxygenase-1 (HO-1), expanding our previous finding that protease inhibitor-induced neurotoxicity was mediated by oxidative stress. Conversely, elvitegravir but not lopinavir led to increased eIF2α phosphorylation, indicating the activation of a common adaptive pathway termed the integrated stress response (ISR), and elvitegravir-mediated neurotoxicity was partially alleviated by the ISR inhibitor trans-ISRIB, suggesting ISR as a promoter of elvitegravir-associated neurotoxicity. Overall, we found that neurotoxicity was induced only by a subset of protease inhibitors and integrase strand transfer inhibitors, providing evidence for class- and drug-specific neurotoxic effects of antiretroviral drugs. Future in vivo studies will be critical to confirm the neurotoxicity profiles of these drugs for incorporation of these findings into patient management. The EAR and ISR pathways are potential access points for the development of adjunctive therapies to complement antiretroviral therapies and limit their contribution to HAND persistence.

HIV-1-associated neurocognitive disorder: epidemiology, pathogenesis, diagnosis, and treatment

The modern antiretroviral treatment of human immunodeficiency virus (HIV-1) infection has considerably lowered the incidence of opportunistic infections. With the exception of the most severe dementia manifestations, the incidence and prevalence of HIV-associated neurocognitive disorders (HAND) have not decreased, and HAND continues to be relevant in daily clinical practice. Now, HAND occurs in earlier stages of HIV infection, and the clinical course differs from that before the widespread use of combination antiretroviral treatment (cART). The predominant clinical feature is a subcortical dementia with deficits in the domains concentration, attention, and memory. Motor signs such as gait disturbance and impaired manual dexterity have become less prominent. Prior to the advent of cART, the cerebral dysfunction could at least partially be explained by the viral load and by virus-associated histopathological findings. In subjects where cART has led to undetectable or at least very low viral load, the pathogenic virus-brain interaction is less direct, and an array of poorly understood immunological and probably toxic phenomena are discussed. This paper gives an overview of the current concepts in the field of HAND and provides suggestions for the diagnostic and therapeutic management.

Cerebrospinal fluid viral load and neopterin in HIV-positive patients with undetectable viraemia

BACKGROUND

Cerebrospinal fluid (CSF) HIV RNA is commonly used as a marker of compartmental antiviral activity in HIV-positive patients. Undetectable CSF HIV RNA levels have been associated with low CSF neopterin levels and better neurocognitive performances. The aim of this study was to analyse the prevalence and predictors of non-detectable CSF HIV RNA using a commercial assay.

METHODS

In adult HIV-positive HAART-treated patients with confirmed plasma HIV RNA <50 copies/ml, CSF HIV RNA (with Roche Amplicor Assay) and neopterin were measured.

RESULTS

112 adult patients were included. Plasma and CSF HIV RNA were non-detectable (target not detected [TND]) in 29 (25.9%) and 36 (32.1%) patients, respectively. CSF TND was observed more frequently in patients with plasma TND (P=0.005, OR=3.87). CSF neopterin levels were associated with age (rho =0.333, P=0.002) and current (rho= -0.272, P=0.015) and nadir (rho =-0.240, P=0.038) CD4⁺ T-lymphocytes; the lowest CSF neopterin concentration was observed in patients with CSF TND versus other viral load strata (0.62 mg/dl versus 0.78 mg/dl; P=0.048).

CONCLUSIONS

Efficaciously treated HIV-positive patients with detectable plasma HIV RNA might imperfectly control CSF viral replication. Prospective studies addressing the management and neurocognitive consequences of CSF low-level viraemia are warranted.

Prevalence and Correlates of Persistent HIV-1 RNA in Cerebrospinal Fluid During Antiretroviral Therapy

BACKGROUND

 Neurocognitive disorders remain common among human immunodeficiency virus (HIV)-positive adults, perhaps owing to persistent HIV-1 RNA in cerebrospinal fluid (CSF) during antiretroviral therapy (ART).

METHODS

 Using a single-copy assay, we measured HIV-1 RNA levels in CSF and plasma specimens from 220 HIV-positive adults who were taking suppressive ART. Fifty-five participants were tested twice.

RESULTS

 HIV-1 RNA was detected in 42.3% of CSF and 65.2% of plasma samples. Correlates of higher CSF HIV-1 RNA levels included higher nadir and current CD4⁺ T-cell counts, a plasma HIV-1 RNA level of ≥ 1 copy/mL, and a lower central nervous system penetration-effectiveness score (model P < .001). Worse neurocognitive performance was associated with discordance in HIV-1 RNA detection between plasma and CSF, lower overall CSF HIV-1 RNA level, and longer ART duration, among others (model P < .001). In the longitudinal subgroup, CSF HIV-1 RNA persisted in most participants (69%) over 7 months.

CONCLUSIONS

 Low-level HIV-1 RNA in CSF is common during suppressive ART and is associated with low-level HIV-1 RNA in blood, better immune status, and lower ART drug distribution into CSF. The association between HIV-1 RNA discordance and HIV-associated neurocognitive disorder (HAND) may reflect compartmentalization. The relationship between HAND, lower HIV-1 RNA levels in CSF, and lower CD4⁺ T-cell counts may reflect disturbances in the immune response to HIV-1 in the CNS.

HIV-associated motor neuron disease: HERV-K activation and response to antiretroviral therapy

OBJECTIVE

To determine whether there is activation of human endogenous retrovirus K (HERV-K) in amyotrophic lateral sclerosis in HIV infection and whether it might respond to treatment with antiretroviral drugs.

METHODS

In this case series, we present 5 patients with HIV infection who subsequently developed motor neuron disease involving both upper and lower motor neurons. We monitored HERV-K levels in plasma of 4 of these patients.

RESULTS

Three patients who received antiretroviral therapy had reversal of symptoms within 6 months of onset of neurologic symptoms and the other 2 had slow neurologic progression over several years. Three patients in whom the levels were measured at onset of neurologic symptoms showed elevated HERV-K levels that responded to optimization of antiretroviral therapy for CNS penetration.

CONCLUSIONS

Thus, motor neuron disease in individuals with HIV infection may a treatable entity, but early treatment with CNS-penetrating antiretroviral therapy may be necessary. Monitoring of HERV-K levels may help guide treatment.

Neurotoxicity in the Post-HAART Era: Caution for the Antiretroviral Therapeutics

Despite the advent of highly active antiretroviral therapy (HAART), HIV-associated neurological disorders (HAND) remain a major challenge in human immunodeficiency virus (HIV) treatment. The early implementation of HAART in the infected individuals helps suppress the viral replication in the plasma and other compartments. Several studies also report the beneficial effect of drugs that successfully penetrate central nervous system (CNS). However, recent data in both clinical setup and in in vitro studies indicate CNS toxicity of the antiretrovirals (ARVs). Although the evidence is limited, correlation between prolonged use of ARVs and neurotoxicity strongly suggests that it is essential to study the underlying mechanisms responsible for such toxicity. Furthermore, closer attention toward clinical outcomes is required to screen various ARV regimens for their association with HAND and other comorbidities. A growing body of literature also indicates a possible role of accelerated aging in the antiretroviral therapy-associated neurotoxicity. Lastly, owing to high pill burden, multiple drugs in the HIV treatment also invite a possible role of drug-drug interaction via various cytochrome P450 enzymes. The particular emphasis of this review is to highlight the need to identify alternative approaches in reducing the CNS toxicity of the ARV drugs in HIV-infected individuals.

HIV-Associated Neurocognitive Disorders—An Issue of Growing Importance

Introduction: HIV-associated neurocognitive disorders (HAND) comprise a wide spectrum of cognitive, motor, and mood abnormalities prevalent in people living with HIV and AIDS (PLWHAs). This field of HIV medicine has gained renewed prominence in recent years with evidence contending that anti-retroviral agents with increased central nervous system (CNS) penetration may improve neurocognitive outcomes in those affected. This review aims at evaluating the available evidence and postulating further study direction in Singapore. Materials and Methods: A PubMed search was carried out for original articles and systematic reviews on the subject of HIV-associated neurocognitive disorders, and the results reviewed by the authors. Results: There is a growing body of evidence that HAND is not uncommon, and the advent of highly active anti-retroviral therapy has increased its prevalence by improving the prognosis of HIV infection, and hence increasing the likelihood of diagnosing of this neurocognitive condition. Screening and diagnosing HAND is important, and requires clinical suspicion as well as validated test batteries for optimal accuracy. The authors recommend strategies for detection in the local context involving stepwise targeted screening. Anti-retroviral agents with good CNS penetration and activity, as well as adjunctive neuro-rehabilitative interventions, may improve the impairments experienced by affected individuals. Conclusion: Increased awareness of HAND, with earlier diagnosis and targeted, multi-disciplinary management of this challenging condition, may lead to better all-round outcomes for people living with HIV and AIDS in Singapore. Key words: AIDS, Cognition, Dementia, HAART