HIV Associated Neurocognitive Disorders in the Modern Antiviral Treatment Era: Prevalence, Characteristics, Biomarkers, and Effects of Treatment

Current clinical presentations of AIDS dementia in a tropical environment: study of 26 observations in the neurology department of the University Hospital of Conakry

INTRODUCTION

In sub-Saharan Africa (SSA), the clinical and progressive diagnostic certainty of AIDS dementia is difficult to establish due to under-medicalization and delays in consultation and especially the diversity of etiologies of demented states.

MATERIAL AND METHODS

We carried out a retrospective study of 196 patients hospitalized for dementia syndrome between 2016 and 2021 in the neurology department of the University Hospital of Conakry. The criteria labeled in this study are those retained by the DSM-IV and the classification of the American Academy of Neurology (AAN) developed in accordance with the WHO.

RESULTS

HIV etiology was identified in patients aged 44-67 years (17 women and 19 men). The clinical picture was dominated by severe cognitive disorders, slowed ideation, memory disorders and reduced motor skills associated with personality changes. Neurological examination revealed dysphoric disorders in most patients, sphincter abnormalities in 13 cases and labio-lingual tremor in 11 cases. Diagnosis was based on positive serological tests for HIV1 antibodies (25 cases) and HIV2 antibodies (1 case) using the Elisa and Western blot techniques, and the presence of discretely hypercellular CSF. Magnetic resonance imaging contributed to the diagnosis, showing diffuse white matter abnormalities with hyper signals on T2-weighted or FLAIR sequences.

CONCLUSION

This study shows a non-stereotype clinical picture of AIDS dementia requiring a differential diagnosis with other infectious dementias. These results are important for the therapeutic and prognostic discussion.

Neuropsychological Test Norms for the Assessment of HIV-Associated Neurocognitive Impairment Among South African Adults

Reliable and valid neurocognitive (NC) test batteries that assess multiple domains of cognitive functioning are vital tools in the early detection of HIV-associated NC impairment. The HIV Neurobehavioral Research Center's International Neurobehavioral Battery (HNRC Battery) is one such diagnostic tool and has shown cultural validity in several international neuroHIV studies. However, no published norms are currently available for the full HNRC Battery in South Africa. To accurately interpret NC test results, appropriate reference norms are required. In light of this challenge, data were collected from 500 healthy, HIV-uninfected participants to develop demographically corrected South African norms. When demographically corrected United States of America (U.S.) norms were applied to the performance scores of our neurologically intact, HIV-negative sample, an impairment rate of 62.2% was observed compared to a 15.0% impairment rate when the newly generated South African norms were applied. These results reiterate the findings of other low- and middle-income countries, highlighting the need for localized, country-specific norms when interpreting NC performance.

Assessment and Diagnosis of HIV-Associated Dementia

The modern combined antiretroviral treatment (cART) for human immunodeficiency virus (HIV) infection has substantially lowered the incidence of HIV-associated dementia (HAD). The dominant clinical features include deficits in cognitive processing speed, concentration, attention, and memory. As people living with HIV become older, with high rates of comorbidities and concomitant treatments, the prevalence and complexity of cognitive impairment are expected to increase. Currently, the management of HAD and milder forms of HAND is grounded on the best clinical practice, as there is no specific, evidence-based, proven intervention for managing cognitive impairment. The present article acknowledges the multifactorial nature of the cognitive impairments found in HIV patients, outlining the current concepts in the field of HAD. Major areas of interest include neuropsychological testing and neuroimaging to evaluate CNS status, focusing on greater reliability in the exclusion of associated diseases and allowing for earlier diagnosis. Additionally, we considered the evidence for neurological involvement in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the impact of the coronavirus (COVID-19) pandemic, with wider consequences to population health than can be attributed to the virus itself. The indirect effects of COVID-19, including the increased adoption of telehealth, decreased access to community resources, and social isolation, represent a significant health burden, disproportionately affecting older adults with dementia who have limited social networks and increased functional dependence on the community and health system. This synopsis reviews these aspects in greater detail, identifying key gaps and opportunities for researchers and clinicians; we provide an overview of the current concepts in the field of HAD, with suggestions for diagnosing and managing this important neurological complication, which is intended to be applicable across diverse populations, in line with clinical observations, and closely representative of HIV brain pathology.

Misdiagnosis of HIV With Toxoplasmosis Encephalopathy With Progressive Memory Loss as the Initial Symptom: A Case Report

Toxoplasmosis encephalopathy (TE) is a kind of encephalopathy parasitic disease caused by Toxoplasma gondii. It is the most common opportunistic for central system infection in patients with acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus. Without early diagnosis and proper treatment, this opportunistic infection can be life-threatening. The common clinical manifestations of the disease include altered mental state, epilepsy, cranial nerve damage, paresthesia, cerebellar signs, meningitis, motor disorders, and neuropsychiatry. The most common presentation in about 75% of cases is a subacute episode of focal neurological abnormalities such as hemiplegia, personality changes, or aphasia. Imaging needs to be differentiated from multiple sclerosis, lymphoma, and metastases. We report a case of acquired immune deficiency syndrome complicated with toxoplasma encephalopathy with rapid progressive memory loss as the initial symptom and misdiagnosed as multiple sclerosis. Through the comprehensive analysis of the clinical symptoms and imaging examination of this disease, we hope to enhance the confidence of clinicians in the diagnosis of this disease.

Evidence for neuropsychological health disparities in Black Americans with HIV disease

OBJECTIVE

Black Americans are at high risk for HIV disease and associated morbidity. The impact and clinical correlates of HIV-associated neurocognitive impairment among Black Americans is not fully understood. The current study uses a full factorial design to examine the independent and combined effects of race and HIV disease on neurocognitive functioning, including its associations with everyday functioning and clinical disease markers in Black and White persons with HIV (PWH).

METHOD

Participants included 40 Black PWH, 83 White PWH, 28 Black HIV- and 64 White HIV- individuals. Neurocognition was measured by raw sample-based z-scores from a clinical battery. Everyday functioning was assessed using self- and clinician-rated measures of cognitive symptoms and activities of daily living. HIV-associated neurocognitive disorders were also classified using demographically adjusted normative standards and the Frascati criteria.

RESULTS

We observed a significant three-way interaction between HIV, race, and domain on raw neurocognitive z-scores. This omnibus effect was driven by medium and large effect size decrements in processing speed and semantic memory, respectively, in Black PWH compared to other study groups. Black PWH also demonstrated higher frequencies of HIV-associated neurocognitive disorders as compared to White PWH. Unexpectedly, global neurocognitive performance was negatively related to everyday functioning impairments for White PWH, but not for Black PWH.

CONCLUSIONS

Systemic disadvantages for Black Americans may combine with HIV disease to compound some neurocognitive impairments in this under-served population. Prospective studies are needed to identify better ways to prevent, measure, diagnose, and manage HIV-associated neurocognitive disorders among Black Americans.

Worldwide Occurrence of HIV-Associated Neurocognitive Disorders and Its Associated Factors: A Systematic Review and Meta-Analysis

BACKGROUND

HIV-associated neurocognitive disorders are common in people living with HIV/AIDS and affect the adherence of patients to prescriptions, activities of daily living, and quality of life of patients. However, there is a lack of summative evidence in the area. The present meta-analysis was therefore addressing this gap.

METHODS

We did our electronic search in Psych-Info, EMBASE, Scopus, and PubMed. The retrieved articles were stored with the endnote reference manager and data was extracted using Meta-XL version 5.3. The quality of studies was evaluated with the modified Newcastle-Ottawa Scale (NOS). A random-effect model and STATA-16 were used to compute the average estimate of HAND. Heterogeneity was weighed with I² statistics. A sensitivity analysis and subgroup analysis were employed. The existence/nonexistence of a publication bias was checked with the Eggers test of publication bias.

RESULTS

The average prevalence of HAND was 50.41% (95% CI: 45.56, 55.26). The average estimate of HAND in Europe was found to be 50.015% whereas in Africa, Asia, and the United States of America (USA) it was 49.566, 52.032, and 50.407% respectively. The prevalence of HAND in studies that used the HIV Dementia Scale (IHDS) was 36.883% and 59.956% at cutoff points of IHDS <9.5 and IHDS <10 respectively. Besides, the estimated average of HAND with the global dementia scale (GDS) was 40.766%. The prevalence of HAND in cross-sectional, cohort, and case-control studies was 49.52, 54.087, and 44.45% in that order. Socio-demographic variables; low level of education and older age, clinical and HIV related variables; the advanced stage of the illness and CD4 count of 500 cells/dl or less and psychological variables such as comorbidity of depression increases the risk of HAND.

CONCLUSION

The prevalence of HIV-associated neurocognitive disorders was about 50.41%. Low level of education and older age, clinical and HIV related variables such as the advanced stage of the illness and CD4 count of 500 cells/dl or less, and comorbidity of depression were associated with HIV associated neurocognitive disorders. Public health interventions for HIV patients should target these essential problems.

International HIV Dementia Scale for HIV-Associated Neurocognitive Disorders: A Systematic Review and Meta-Analysis

The present study aims to systematically review the evidence on the accuracy of the International HIV Dementia Scale (IHDS) test for diagnosing human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) and outline the quality and quantity of research evidence available on the accuracy of IHDS in people living with HIV. We conducted a systematic literature review, searching five databases from inception until July 2020. We extracted dichotomized positive and negative test results at various thresholds and calculated the sensitivity and specificity of IHDS. Quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) criteria. Fifteen cross-sectional studies, published between 2011 and 2018, met the inclusion criteria for meta-analysis. Overall, 3760 patients were included, but most studies recruited small samples. We assessed most studies as being applicable to the review question, though we had concerns about the selection of participants in three studies. The accuracy of IHDS was investigated at thirteen cut-off points (scores 6-12). The threshold of 10 is the most useful for optimal HAND screening (including asymptomatic neurocognitive disorder, symptomatic HAND, and HIV-associated dementia) with fair diagnostic accuracy.

Mini review: Promotion of substance abuse in HIV patients: Biological mediation by HIV-1 Tat protein

Despite successful viral suppression by combinatorial anti-retroviral therapy, HIV infection continues to negatively impact the quality of life of patients by promoting neuropathy and HIV-Associated Neurocognitive Disorders (HAND), where substance use disorder (SUD) is highly comorbid and known to worsen health outcomes. While substance abuse exacerbates the progression of HIV, emerging evidence also suggests the virus may potentiate the rewarding effect of abused substances. As HIV does not infect neurons, these effects are theorized to be mediated by viral proteins. Key among these proteins are HIV-1 Tat, which can continue to be produced under viral suppression in patients. This review will recap the behavioral evidence for HIV-1 Tat mediation of a potentiation of cocaine, opioid and alcohol reward, and explore the neurochemical dysfunction associated by Tat as potential mechanisms underlying changes in reward. Targeting rampant oxidative stress, inflammation and excitotoxicity associated with HIV and Tat protein exposure may prove useful in combating persistent substance abuse comorbid with HIV in the clinic.

Modulation of BRD4 in HIV epigenetic regulation: implications for finding an HIV cure

Following reverse transcription, HIV viral DNA is integrated into host cell genomes and establishes a stable latent infection, which has posed a major obstacle for obtaining a cure for HIV. HIV proviral transcription is regulated in cellular reservoirs by complex host epigenetic and transcriptional machineries. The Bromodomain (BD) and Extra-Terminal Domain (ET) protein, BRD4, is an important epigenetic reader that interacts with acetyl-histones and a variety of chromatin and transcriptional regulators to control gene expression, including HIV. Modulation of BRD4 by a pan BET inhibitor (JQ1) has been shown to activate HIV transcription. Recent studies by my group and others indicate that the function of BRD4 is versatile and its effects on HIV transcription may depend on the partner proteins or pathways engaged by BRD4. Our studies have reported a novel class of small-molecule modulators that are distinct from JQ1 but induce HIV transcriptional suppression through BRD4. Herein, we reviewed recent research on the modulation of BRD4 in HIV epigenetic regulation and discussed their potential implications for finding an HIV cure.

Comprehensive Geriatric Assessment in Older Persons With HIV

With increased longevity related to the advent of antiretroviral therapy, there are increasing proportions of older persons with HIV (PWH). Prior studies have demonstrated increased prevalence of geriatric syndromes in older PWH and recommended the Comprehensive Geriatric Assessment (CGA) in this population. However, there is currently no peer-reviewed literature that outlines how to perform the CGA in PWH in the clinical setting. In this article, we offer a review on how to perform the CGA in PWH, outline domains of the CGA and their importance in PWH, and describe screening tools for each domain focusing on tools that have been validated in PWH, are easy to administer, and/or are already commonly used in the field of geriatrics.

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.

Epigenetic Suppression of HIV in Myeloid Cells by the BRD4-Selective Small Molecule Modulator ZL0580

Brain-resident microglia and myeloid cells (perivascular macrophages) are important HIV reservoirs in vivo, especially in the central nervous system (CNS). Despite antiretroviral therapy (ART), low-level persistent HIV replication in these reservoirs remains detectable, which contributes to neuroinflammation and neurological disorders in HIV-infected patients. New approaches complementary to ART to repress residual HIV replication in CNS reservoirs are needed. Our group has recently identified a BRD4-selective small molecule modulator (ZL0580) that induces the epigenetic suppression of HIV. Here, we examined the effects of this compound on HIV in human myeloid cells. We found that ZL0580 induces potent and durable suppression of both induced and basal HIV transcription in microglial cells (HC69) and monocytic cell lines (U1 and OM10.1). Pretreatment of microglia with ZL0580 renders them more refractory to latent HIV reactivation, indicating an epigenetic reprogramming effect of ZL0580 on HIV long terminal repeat (LTR) in microglia. We also demonstrate that ZL0580 induces repressive effect on HIV in human primary monocyte-derived macrophages (MDMs) by promoting HIV suppression during ART treatment. Mechanistically, ZL0580 inhibits Tat transactivation in microglia by disrupting binding of Tat to CDK9, a process key to HIV transcription elongation. High-resolution micrococcal nuclease mapping showed that ZL0580 induces a repressive chromatin structure at the HIV LTR. Taken together, our data suggest that ZL0580 represents a potential approach that could be used in combination with ART to suppress residual HIV replication and/or latent HIV reactivation in CNS reservoirs, thereby reducing HIV-associated neuroinflammation.IMPORTANCE Brain-resident microglia and perivascular macrophages are important HIV reservoirs in the CNS. Persistent viral replication and latent HIV reactivation in the CNS, even under ART, are believed to occur, causing neuroinflammation and neurological disorders in HIV-infected patients. It is critical to identify new approaches that can control residual HIV replication and/or latent HIV reactivation in these reservoirs. We here report that the BRD4-selective small molecule modulator, ZL0580, induces potent and durable suppression of HIV in human microglial and monocytic cell lines. Using an in vitro HIV-infected, ART-treated MDM model, we show that ZL0580 also induces suppressive effect on HIV in human primary macrophages. The significance of our research is that it suggests a potential new approach that has utility in combination with ART to suppress residual HIV replication and/or HIV reactivation in CNS reservoirs, thereby reducing neuroinflammation and neurological disorders in HIV-infected individuals.

Heme oxygenase-1 promoter (GT) n polymorphism associates with HIV neurocognitive impairment

Objective

To determine whether regulatory variations in the heme oxygenase-1 (HO-1) promoter (GT)_n dinucleotide repeat length could identify unique population genetic risks for neurocognitive impairment (NCI) in persons living with HIV (PLWH), we genotyped 528 neurocognitively assessed PLWH of European American and African American descent and linked genotypes to cognitive status.

Methods

In this cross-sectional study of PLWH (the CNS HIV Antiretroviral Therapy Effect Research cohort), we determined HO-1 (GT)_n repeat lengths in 276 African Americans and 252 European Americans. Using validated criteria for HIV-associated NCI (HIV NCI), we found associations between allele length genotypes and HIV NCI and between genotypes and plasma markers of monocyte activation and inflammation. For comparison of HO-1 (GT)_n allele frequencies with another population of African ancestry, we determined HO-1 (GT)_n allele lengths in African PLWH from Botswana (n = 428).

Results

PLWH with short HO-1 (GT)_n alleles had a lower risk for HIV NCI (OR = 0.63, 95% CI: 0.42–0.94). People of African ancestry had a lower prevalence of short alleles and higher prevalence of long alleles compared with European Americans, and in subgroup analyses, the protective effect of the short allele was observed in African Americans and not in European Americans.

Conclusions

Our study identified the short HO-1 (GT)_n allele as partially protective against developing HIV NCI. It further suggests that this clinical protective effect is particularly relevant in persons of African ancestry, where the lower prevalence of short HO-1 (GT)_n alleles may limit induction of HO-1 expression in response to inflammation and oxidative stress. Therapeutic strategies that enhance HO-1 expression may decrease HIV-associated neuroinflammation and limit HIV NCI.

Gross motor developmental delay in human immunodeficiency virus-infected children under 2 years of age

Background:

Human immunodeficiency virus (HIV) infection has significant effects on child development. We report the outcome of gross motor developmental assessment in HIV-infected children <2 years compared with that of uninfected children.

Materials and Methods:

Every child <2 years of age presenting for the first time to the pediatric outpatient department of the hospital over 3 months was studied. Each child had a physical examination with gross motor milestone assessment, as well as initial double rapid HIV antibody tests with confirmatory tests for those with positive or discordant results. Children with evidence of motor delay were booked for reassessment after 1 month. The milestone performance criteria of the Multicenter Growth Reference Study of the World Health Organization were used as a standard.

Results:

One hundred and eight children were studied. Male-to-female ratio was 1:1. Fourteen children (13.0%) were HIV infected. Nine children (8.3%) had delayed development of gross motor milestones, of which five were HIV infected and four were uninfected (P = 0.001). Each motor milestone was attained at a significantly later mean age by the HIV-infected children when compared to the uninfected. Evidence of delay in gross motor milestones was apparent by the first 6 months of life.

Conclusions:

A tendency to poorer motor development is apparent in young children infected by HIV and can manifest as early as the first 6 months of life. Routine HIV screening as well as early developmental assessment of all children should be encouraged.

An Empirical Mediation Analysis of Mechanisms Underlying HIV-1-Associated Neurocognitive Disorders

HIV-1-associated neurocognitive disorders (HAND), characterized by alterations in the core components of cognitive function and age-related disease progression, persist in the post-cART era. However, the neurobehavioral mechanisms that mediate alterations in the core components of cognitive function and the progression of neurocognitive impairments have yet to be systematically evaluated. To address this knowledge gap, statistical mediation analysis was assessed, providing a critical opportunity to empirically evaluate putative neurobehavioral mechanisms underlying HAND. Neurocognitive assessments, conducted in HIV-1 transgenic (Tg) and control animals across the functional lifespan (i.e., Postnatal Day (PD) 30 to PD 600), tapped multiple cognitive domains including preattentive processes, learning, sustained attention, and long-term episodic memory. Three longitudinal mediation models were utilized to assess whether deficits in preattentive processes mediate alterations in learning, sustained attention and/or long-term episodic memory over time. Preattentive processes partially mediated the relationship between genotype and learning, genotype and sustained attention, and genotype and long-term episodic memory across the functional lifespan, explaining between 44% and 58% of the HIV-1 transgene effect. Understanding the neurobehavioral mechanisms mediating alterations in HAND may provide key targets for the development of a diagnostic biomarker, novel therapeutics, and cure/restoration strategies.

Montreal Cognitive Assessment (MoCA) for HIV-Associated Neurocognitive Disorders

This study aims to systematically review the evidence on the accuracy of the Montreal Cognitive Assessment (MoCA) test for diagnosing HIV-associated neurocognitive disorders (HAND) and to outline the quality and quantity of research evidence available about the accuracy of MoCA in populations infected with HIV. We conducted a systematic literature review, searching five databases from inception until January 2019. We extracted dichotomized positive and negative test results at various thresholds and calculated the sensitivity and specificity of MoCA. Quality assessment was performed according to the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) criteria. Eight cross-sectional studies met the inclusion criteria for meta-analysis. Overall, 1014 patients were included but most studies recruited small samples. Recruitment period ranged from 2009 to 2015. We assessed most studies as being applicable to the review question though we had concerns about the selection of participants in three studies. The accuracy of MoCA for diagnosing HAND was reported at six cut-off points (scores 22-27). The MoCA test provides information about general cognitive functioning disturbances that contribute to a diagnosis of HAND. A lower threshold than the original cut-off of 26 is probably more useful for optimal screening of HAND, as it lowers false positive rates and improves diagnostic accuracy. Nonetheless, the choice of cut-off always comes with a sensitivity-specificity trade-off, the preferred cut point depending on whether sensitivity or specificity is more valuable in a given context.

Helix-A peptide prevents gp120-mediated neuronal loss

Aim

The human-immunodeficiency virus (HIV) envelope protein gp120 promotes synaptic damage similar to that observed in people living with HIV who have neurocognitive disorders. The neurotoxic effect of gp120 appears to occur through the α-helix motif that binds to neuronal microtubules (MTs). In this study, we examined the ability of short peptide derivatives from Helix-A, a peptide synthesized based on α-helix structure of gp120, to displace gp120 from binding to MTs and prevent its neurotoxic effects.

Methods

Surface plasmon resonance was used to determine the binding of Helix-A and its modifications to MTs. Helix-A peptide and derivatives were delivered inside rat primary cortical neurons by mesoporous silica nanoparticles (MSN). Neuronal processes and survival were evaluated by microtubule associated protein 2-immunostaining and Hoechst/Propidium iodide, respectively.

Results

Surface plasmon resonance analysis revealed that Helix-A but not its modifications binds to MTs. Also, only Helix-A MSN but not other peptides prevented the ability of gp120 to reduce neuronal processes as well as neuronal survival. Thus, the amino acid structure of Helix-A is key for its neuroprotective activity.

Altered Immunity and Microbial Dysbiosis in Aged Individuals With Long-Term Controlled HIV Infection

The introduction of highly active antiretroviral therapy (HAART) resulted in a significant increase in life expectancy for HIV patients. Indeed, in 2015, 45% of the HIV+ individuals in the United States were ≥55 years of age. Despite improvements in diagnosis and treatment of HIV infection, geriatric HIV+ patients suffer from higher incidence of comorbidities compared to age-matched HIV- individuals. Both chronic inflammation and dysbiosis of the gut microbiome are believed to be major contributors to this phenomenon, however carefully controlled studies investigating the impact of long-term (>10 years) controlled HIV (LTC-HIV) infection are lacking. To address this question, we profiled circulating immune cells, immune mediators, and the gut microbiome from elderly (≥55 years old) LTC-HIV+ and HIV- gay men living in the Palm Springs area. LTC-HIV+ individuals had lower frequency of circulating monocytes and CD4+ T-cells, and increased frequency CD8+ T-cells. Moreover, levels of systemic INFγ and several growth factors were increased while levels of IL-2 and several chemokines were reduced. Upon stimulation, immune cells from LTC-HIV+ individuals produced higher levels of pro-inflammatory cytokines. Last but not least, the gut microbiome of LTC-HIV+ individuals was enriched in bacterial taxa typically found in the oral cavity suggestive of loss of compartmentalization, while levels of beneficial butyrate producing taxa were reduced. Additionally, prevalence of Prevotella negatively correlated with CD4+ T-cells numbers in LTC-HIV+ individuals. These results indicate that despite long-term adherence and undetectable viral loads, LTC-HIV infection results in significant shifts in immune cell frequencies and gut microbial communities.

The Glucocorticoid Receptor Is a Critical Regulator of HIV Latency in Human Microglial Cells

We have developed models of HIV latency using microglia derived from adult human patient brain cortex and transformed with the SV40 T large and hTERT antigens. Latent clones infected by HIV reporter viruses display high levels of spontaneous HIV reactivation in culture. BrainPhys, a medium highly representative of the CNS extracellular environment, containing low glucose and 1% FBS, reduced, but did not prevent, HIV reactivation. We hypothesized that spontaneous HIV reactivation in culture was due to the expression of pro-inflammatory genes, such as TNF-α, taking place in the absence of the natural inhibitory signals from astrocytes and neurons. Indeed, expression and secretion of TNF-α is strongly reduced in HIV-latently infected microglia compared to the subset of cells that have undergone spontaneous HIV reactivation. Whereas inhibitors of NF-κB or of macrophage activation only had a short-term silencing effect, addition of dexamethasone (DEXA), a glucocorticoid receptor (GR) agonist and mediator of anti-inflammation, silenced the HIV provirus in a long-term, and shRNA-mediated knock-down of GR activated HIV. DEXA also decreased secretion of a number of cytokines, including TNF-α. Chromatin immunoprecipitation analysis revealed that DEXA strongly increased GR occupancy at the HIV promoter, and reduced histone 3 acetylated levels. Moreover, TNF-α expression inhibitors in combination with DEXA induced further HIV silencing and increased the histone 3 lysine 27 tri-methylated epigenetic mark of repression at the HIV promoter region. We conclude that GR is a critical repressor of HIV transcription in microglia, and a novel potential pharmacological target to restrict HIV expression in the CNS.

Diagnostic and prognostic biomarkers for HAND

In 2007, the nosology for HIV-1-associated neurocognitive disorders (HAND) was updated to a primarily neurocognitive disorder. However, currently available diagnostic tools lack the sensitivity and specificity needed for an accurate diagnosis for HAND. Scientists and clinicians, therefore, have been on a quest for an innovative biomarker to diagnose (i.e., diagnostic biomarker) and/or predict (i.e., prognostic biomarker) the progression of HAND in the post-combination antiretroviral therapy (cART) era. The present review examined the utility and challenges of four proposed biomarkers, including neurofilament light (NFL) chain concentration, amyloid (i.e., sAPPα, sAPPβ, amyloid β) and tau proteins (i.e., total tau, phosphorylated tau), resting-state functional magnetic resonance imaging (fMRI), and prepulse inhibition (PPI). Although significant genotypic differences have been observed in NFL chain concentration, sAPPα, sAPPβ, amyloid β, total tau, phosphorylated tau, and resting-state fMRI, inconsistencies and/or assessment limitations (e.g., invasive procedures, lack of disease specificity, cost) challenge their utility as a diagnostic and/or prognostic biomarker for milder forms of neurocognitive impairment (NCI) in the post-cART era. However, critical evaluation of the literature supports the utility of PPI as a powerful diagnostic biomarker with high accuracy (i.e., 86.7-97.1%), sensitivity (i.e., 89.3-100%), and specificity (i.e., 79.5-94.1%). Additionally, the inclusion of multiple CSF and/or plasma markers, rather than a single protein, may provide a more sensitive diagnostic biomarker for HAND; however, a pressing need for additional research remains. Most notably, PPI may serve as a prognostic biomarker for milder forms of NCI, evidenced by its ability to predict later NCI in higher-order cognitive domains with regression coefficients (i.e., r) greater than 0.8. Thus, PPI heralds an opportunity for the development of a brief, noninvasive diagnostic and promising prognostic biomarker for milder forms of NCI in the post-cART era.

The integrated National NeuroAIDS Tissue Consortium database: a rich platform for neuroHIV research

Herein we present major updates to the National NeuroAIDS Tissue Consortium (NNTC) database. The NNTC's ongoing multisite clinical research study was established to facilitate access to ante-mortem and post-mortem data, tissues and biofluids for the neurohuman immunodeficiency virus (HIV) research community. Recently, the NNTC has expanded to include data from the central nervous system HIV Antiretroviral Therapy Effects Research (CHARTER) study. The data and biospecimens from CHARTER and NNTC cohorts are available to qualified researchers upon request. Data generated by requestors using NNTC biospecimens and tissues are returned to the NNTC upon the conclusion of requestors' work, and this external, experimental data are annotated and curated in the publically accessible NNTC database, thereby extending the utility of each case. A flexible and extensible database ontology allows the integration of disparate data sets, including external experimental data, clinical neuropsychological and neuromedical testing data, tissue pathology and neuroimaging data.

Comorbid depression and apathy in HIV-associated neurocognitive disorders in the era of chronic HIV infection

This chapter provides an overview of the current research on the question of depression and apathy in HIV-associated neurocognitive disorders (HAND) in the era of chronic HIV infection. After presenting the epidemiology of each condition showing that depression and apathy are the two most frequent psychiatric comorbidities of HAND, we review the current research, particularly in relation to the milder forms of HAND that characterize treated HIV cohorts. Doing so, we include findings on depression and apathy in non-HIV aging population and the risk of dementia, findings that are relevant to the aging HIV cohorts carrying a high burden of psychiatric comorbidities. We then present a review of the research pertaining to the differentiation between depression and apathy. A section is dedicated to the question of suicidality in chronic HIV infection, which is underappreciated. An overview of the pharmacologic and psychosocial interventions relevant to depression and apathy in HIV cohorts treated with antiretroviral treatment is provided. The chapter concludes with future directions for the research on apathy and depression with emphasis on the question of aging and the need for longitudinal studies.

Tenofovir disoproxil fumarate induces pheochromocytoma cells apoptosis

Despite the triumph of highly active antiretroviral therapy (HAART) in anti-HIV infection, more than half of the HIV infection individuals receiving antiretroviral therapy acquire HIV-associated neurocognitive disorder (HAND). Previously researches had reported that the HAART neurotoxicity is implicated in HAND-related morbidity. The molecular mechanism of HAND is not clear. Tenofovir disoproxil fumarate (TDF) is a novel nucleotide reverse transcriptase inhibitor (NRTI), which was recommended as first-line therapeutic schedule for free AIDS antiviral drugs. Whether the neurotoxicity of TDF is associated with HAND is not well known. In this study, the cell viability of TDF-treated pheochromocytoma cells (PC-12) line was detected using MTT assay, while apoptosis was evaluated by Hoechst 33342 staining, TUNEL assay, as well as flow cytometry. In addition, the level of reactive oxygen species and BAX protein expression were evaluated using DCFH-DA staining and western blotting. The results showed that the proliferation of PC-12 cells was significantly inhibited by TDF. The morphological assay, TUNEL assay and flow cytometry showed that TDF efficiently triggered apoptosis in PC-12 cells. The reactive oxygen species levels were BAX expression was markedly up-regulated in PC-12 cells after treatment with TDF. These findings indicated that TDF may induce PC-12 cell apoptosis. TDF has neural toxicity effect that is relevant to the cell apoptosis, which may be related to the increasing prevalence of HAND.

Role of Macrophage Dopamine Receptors in Mediating Cytokine Production: Implications for Neuroinflammation in the Context of HIV-Associated Neurocognitive Disorders

Despite the success of combination anti-retroviral therapy (cART), around 50% of HIV-infected individuals still display a variety of neuropathological and neurocognitive sequelae known as NeuroHIV. Current research suggests these effects are mediated by long-term changes in CNS function in response to chronic infection and inflammation, and not solely due to active viral replication. In the post-cART era, drug abuse is a major risk-factor for the development of NeuroHIV, and increases extracellular dopamine in the CNS. Our lab has previously shown that dopamine can increase HIV infection of primary human macrophages and increase the production of inflammatory cytokines, suggesting that elevated dopamine could enhance the development of HIV-associated neuropathology. However, the precise mechanism(s) by which elevated dopamine could exacerbate NeuroHIV, particularly in chronically-infected, virally suppressed individuals remain unclear. To determine the connection between dopaminergic alterations and HIV-associated neuroinflammation, we have examined the impact of dopamine exposure on macrophages from healthy and virally suppressed, chronically infected HIV patients. Our data show that dopamine treatment of human macrophages isolated from healthy and cART-treated donors promotes production of inflammatory mediators including IL-1β, IL-6, IL-18, CCL2, CXCL8, CXCL9, and CXCL10. Furthermore, in healthy individuals, dopamine-mediated modulation of specific cytokines is correlated with macrophage expression of dopamine-receptor transcripts, particularly DRD5, the most highly-expressed dopamine-receptor subtype. Overall, these data will provide more understanding of the role of dopamine in the development of NeuroHIV, and may suggest new molecules or pathways that can be useful as therapeutic targets during HIV infection.

United States National Trends in Mortality, Length of Stay (LOS) and Associated Costs of Cognitive Impairment in HIV Population from 2005 to 2014

We evaluated national trends of in-hospital discharge rates, mortality outcomes, health care costs, length of stay in HIV patients with cognitive disorders. Neurological involvement in HIV is commonly associated with cognitive impairment termed as HIV-associated neurocognitive disorder (HAND) which includes a spectrum of neurocognitive dysfunction associated with HIV infection. Although severe and progressive neurocognitive impairment has become rare in HIV patients in the era of potent antiretroviral therapy, a majority of HIV patients have mild to moderate degree of neurocognitive impairment. Study population for this analysis was derived from the Nationwide Inpatient Sample from 2005 to 2014. Patients with ICD-9 code of HIV (042) with discharge diagnosis (Dx) listed top 1 through 5 were included in the analysis. Within this population, we identified patients with cognitive impairment using ICD-9 codes of 294 (persistent mental disorders; organic psychotic brain syndromes (chronic), 323.9 (encephalitis, myelitis, and encephalomyelitis), 331.83 (mild cognitive impairment) with Dx listed from 1 to 25. Patient variables obtained included: age, race, gender, length of stay, in-hospital mortality and insurance status. Hospital level variables included teaching status, location and region of country. SAS 9.4 software was used for data analysis. Comparisons of variables between hospitalized HIV patients with and without HAND showed significant increase in cost per hospital admissions, longer hospital stay and higher risk of mortality in patients with HAND.

Induction of a Senescence-Like Phenotype in Cultured Human Fetal Microglia During HIV-1 Infection

HIV-1 causes premature aging in chronically infected patients. Despite effective anti-retroviral therapy, around 50% of patients suffer HIV-associated neurocognitive disorders (HAND), which likely potentiate aging-associated neurocognitive decline. Microglia support productive HIV-1 infection in the brain. Elevated markers of cellular senescence, including p53 and p21, have been detected in brain tissues from patients with HAND, but the potential for microglia senescence during HIV-1 infection has not been investigated. We hypothesized that HIV-1 can induce senescence in microglia. Primary human fetal microglia were exposed to single-round infectious HIV-1 pseudotypes or controls, and examined for markers of senescence. Post-infection, microglia had significantly elevated: senescence-associated β-galactosidase activity, p21 levels, and production of cytokines such as IL-6 and IL-8, potentially indicative of a senescence-associated secretory phenotype. We also found increased detection of p53-binding protein foci in microglia nuclei post-infection. Additionally, we examined mitochondrial reactive oxygen species (ROS) and respiration, and found significantly increased mitochondrial ROS levels and decreased ATP-linked respiration during HIV-1 infection. Supernatant transfer from infected cultures to naïve microglia resulted in elevated p21 and caveolin-1 levels, and IL-8 production. Finally, nucleoside treatment reduced senescence markers induction in microglia. Overall, HIV-1 induces a senescence-like phenotype in human microglia, which could play a role in HAND.

Executive Functions Rating Scale and Neurobiochemical Profile in HIV-Positive Individuals

The set of complex cognitive processes, that are necessary for the cognitive control of behavior, known as executive functions (EF), are traditionally associated with the prefrontal cortex and commonly assessed with laboratory based tests and conventional neuroimaging. In an effort to produce a more complete and ecologically valid understanding of executive functioning, the rating scales have been developed in order to assess the behavioral aspects of EF within an everyday real-world context. The main objective of this study was to examine the relationship between behavioral aspects of EF measured by rating scale and neurometabolic profile in neurologically asymptomatic HIV-positive individuals under cART, measured using multi-voxel magnetic resonance spectroscopy (mvMRS). The sample comprised 39 HIV-positive adult male participants, stable on cART and 39 healthy HIV-negative volunteers. Both groups completed the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A). HIV-positive group additionally underwent long-echo three-dimensional mvMRS to determine neurobiochemical profile in the anterior cingulate gyrus (ACG) of both hemispheres. Three dominant neurometabolites were detected: N-acetyl aspartate (NAA), the neuronal marker; choline (Cho), the marker of membrane metabolism and gliosis and creatine (Cr), the reference marker. Ratios of NAA/Cr and Cho/Cr were analyzed. The initially detected significant correlations between age, current CD4, BRIEF-A subscales Inhibit, Shift, Emotional Control, Plan/Organize, Self Monitoring and ratios of NAA/Cr and Cho/Cr in the dorsal and ventral part of the ACG, were lost after the introduction of Bonferroni corrections. Also, there were no significant differences between HIV–positive and HIV–negative group on any of BRIEF-A subscales. Such results possibly imply that stable cART regimen contributes to preservation of behavioral aspects of EF in asymptomatic HIV-positive individuals. Even though a subtle deficit in some aspects of EF might exist, it would not be manifest if behavioral aspect was assessed using EF rating scale. Further explanation might be that expected HIV-related changes in neurometabolic profile of the ACG under cART are not reflected in those behavioral aspects that are measurable by EF rating scale.

Correlation between inner retinal layer thickness and cognitive function in HIV: new insights from an exploratory study

OBJECTIVE

To compare retinal layer thickness in HIV-infected subjects with (CI-HIV) and without (NCI-HIV) cognitive impairment, with a control population and to correlate this with the cognitive status of the patient and other clinical parameters.

DESIGN

Single-center cross-sectional study.

METHODS

Participants with controlled HIV infection aged between 40 and 70 years and sex-matched and age-matched controls were enrolled. Retinal nerve fiber layer (RNFL), ganglion cell layer (GCL) and inner plexiform layer (IPL) thickness were assessed using optical coherence tomography. These measurements in HIV patients were compared with those in controls. Age-related and sex-related changes were compared in both groups. Other variables studied in HIV patients included: duration of HIV infection, CD4 cell count nadir, antiretroviral therapy regimen and cognitive status using the Montreal Cognitive Assessment (MoCA) test.

RESULTS

Sixty-nine individuals, 34 with and 35 without cognitive impairment, and 70 controls were enrolled. GCL was significantly thinner in CI-HIV patients compared with NCI-HIV patients and controls (P = 0.01 and P = 0.02, respectively). GCL and IPL thickness significantly decreased with age in patients with HIV (P = 0.0003, P = 0.02, respectively, for the entire cohort). This change was not seen in controls. MoCA test score significantly decreased with age in HIV patients and controls. GCL thickness positively correlated with cognitive function across the entire HIV cohort (P = 0.02).

CONCLUSION

GCL was thinner in HIV patients with cognitive impairment. GCL thickness correlated positively with cognitive function and negatively with age in HIV patients. GCL thickness may reflect accelerated cognitive aging in HIV.

Temporal/compartmental changes in viral RNA and neuronal injury in a primate model of NeuroAIDS

Despite the advent of highly active anti-retroviral therapy HIV-associated neurocognitive disorders (HAND) continue to be a significant problem. Furthermore, the precise pathogenesis of this neurodegeneration is still unclear. The objective of this study was to examine the relationship between infection by the simian immunodeficiency virus (SIV) and neuronal injury in the rhesus macaque using in vivo and postmortem sampling techniques. The effect of SIV infection in 23 adult rhesus macaques was investigated using an accelerated NeuroAIDS model. Disease progression was modulated either with combination anti-retroviral therapy (cART, 4 animals) or minocycline (7 animals). Twelve animals remained untreated. Viral loads were monitored in the blood and cerebral spinal fluid, as were levels of activated monocytes in the blood. Neuronal injury was monitored in vivo using magnetic resonance spectroscopy. Viral RNA was quantified in brain tissue of each animal postmortem using reverse transcription polymerase chain reaction (RT-PCR), and neuronal injury was assessed by immunohistochemistry. Without treatment, viral RNA in plasma, cerebral spinal fluid, and brain tissue appears to reach a plateau. Neuronal injury was highly correlated both to plasma viral levels and a subset of infected/activated monocytes (CD14+CD16+), which are known to traffic the virus into the brain. Treatment with either cART or minocycline decreased brain viral levels and partially reversed alterations in in vivo and immunohistochemical markers for neuronal injury. These findings suggest there is significant turnover of replicating virus within the brain and the severity of neuronal injury is directly related to the brain viral load.

Patient perspectives on de-simplifying their single-tablet co-formulated antiretroviral therapy for societal cost savings

OBJECTIVES

The incremental costs of expanding antiretroviral (ARV) drug treatment to all HIV-infected patients are substantial, so cost-saving initiatives are important. Our objectives were to determine the acceptability and financial impact of de-simplifying (i.e. switching) more expensive single-tablet formulations (STFs) to less expensive generic-based multi-tablet components. We determined physician and patient perceptions and acceptance of STF de-simplification within the context of a publicly funded ARV budget.

METHODS

Programme costs were calculated for patients on ARVs followed at the Southern Alberta Clinic, Canada during 2016 (Cdn$). We focused on patients receiving Triumeq® and determined the savings if patients de-simplified to eligible generic co-formulations. We surveyed all prescribing physicians and a convenience sample of patients taking Triumeq® to see if, for budgetary purposes, they felt that de-simplification would be acceptable.

RESULTS

Of 1780 patients receiving ARVs, 62% (n = 1038) were on STF; 58% (n = 607) of patients on STF were on Triumeq®. The total annual cost of ARVs was $26 222 760. The cost for Triumeq® was $8 292 600. If every patient on Triumeq® switched to generic abacavir/lamivudine and Tivicay® (dolutegravir), total costs would decrease by $4 325 040. All physicians (n = 13) felt that de-simplifying could be safely achieved. Forty-eight per cent of 221 patients surveyed were agreeable to de-simplifying for altruistic reasons, 27% said no, and 25% said maybe.

CONCLUSIONS

De-simplifying Triumeq® generates large cost savings. Additional savings could be achieved by de-simplifying other STFs. Both physicians and patients agreed that selective de-simplification was acceptable; however, it may not be acceptable to every patient. Monitoring the medical and cost impacts of de-simplification strategies seems warranted.

Insulin Resistance in HIV-Patients: Causes and Consequences

Here we review how immune activation and insulin resistance contribute to the metabolic alterations observed in HIV-infected patients, and how these alterations increase the risk of developing CVD. The introduction and evolution of antiretroviral drugs over the past 25 years has completely changed the clinical prognosis of HIV-infected patients. The deaths of these individuals are now related to atherosclerotic CVDs, rather than from the viral infection itself. However, HIV infection, cART, and intestinal microbiota are associated with immune activation and insulin resistance, which can lead to the development of a variety of diseases and disorders, especially with regards to CVDs. The increase in LPS and proinflammatory cytokines circulating levels and intracellular mechanisms activate serine kinases, resulting in insulin receptor substrate-1 (IRS-1) serine phosphorylation and consequently a down regulation in insulin signaling. While lifestyle modifications and pharmaceutical interventions can be employed to treat these altered metabolic functions, the mechanisms involved in the development of these chronic complications remain largely unresolved. The elucidation and understanding of these mechanisms will give rise to new classes of drugs that will further improve the quality of life of HIV-infected patients, over the age of 50.

Verbal episodic memory profiles in HIV-Associated Neurocognitive Disorders (HAND): A comparison with Huntington's disease and mesial temporal lobe epilepsy

HIV-associated neurocognitive disorders (HAND) commonly feature verbal episodic memory impairment historically characterized by a retrieval deficit, consistent with a classic "subcortical" presentation; however, there are hints of a subtle shift toward a more "cortical" memory profile characterized by a primary encoding deficit. The current study evaluated this possibility by comparing the pattern of HAND-associated verbal episodic memory deficits to those of traditional "subcortical" (i.e., Huntington's disease; HD) versus "cortical" (i.e., left temporal lobe epilepsy with mesial temporal sclerosis; L-MTLE) profiles. Seventy-seven individuals with HAND, 47 individuals with HD, 21 individuals with L-MTLE, and 45 healthy participants were administered the California Verbal Learning Test - 2^nd Edition (CVLT-II). CVLT-II profiles were classified as reflecting a primary encoding deficit, retrieval deficit, or a normal profile. Among participants with a deficit profile, the HAND group showed the highest rates of retrieval versus encoding profiles (71% vs. 29%), followed by HD (59% vs. 41%), L-MTLE (46% vs. 54%), and healthy (50% vs. 50%) groups. While significant profile heterogeneity was observed across clinical groups, findings suggest that HIV-associated verbal episodic memory impairments are most consistent with a traditional "subcortical," retrieval deficit profile, consistent with the primary frontostriatal neuropathogenesis of HIV disease.

Mechanisms of Cognitive Aging in the HIV-Positive Adult

PURPOSE OF REVIEW

As of the year 2016, an estimated 50% of the United States' HIV-Positive population is aged 50 years or older. Due to a combination of increased rates of infection in older adults, and successful anti-retroviral (ART) regimens allowing HIV-positive adults to survive for decades with the disease, we are now faced with a steadily graying HIV-positive population, with only limited knowledge of how the cognitive and physiological effects of aging intersect with those of chronic HIV-infection.

RECENT FINDINGS

Age-related changes to mood, cognition, and neurological health may be experienced differently in those living with HIV, and research concerning quality of life, mental health, and cognitive aging needs to account for and explore these factors more carefully in the coming years.

SUMMARY

This review will explore the topic of cognitive aging with HIV: 1. Central nervous system (CNS) infection of HIV and how the virus affects brain integrity and function; 2. Cognitive and behavioral symptoms of HIV-Associated Neurocognitive Disorders (HAND); 3. Neurobiological theories of Cognitive Aging and how these processes may be exacerbated by HIV-infection; 4: Clinical implications and complications of aging with HIV and factors that may result in poorer cognitive outcomes.

Selective impairments of alerting and executive control in HIV-infected patients: evidence from attention network test

BACKGROUND

Attention ability can be subdivided into three functionally independent networks, i.e., alerting network, orienting network, and executive network. Previous literature has documented that deficits in attention are a common consequence of HIV infection. However, the precise nature of deficits of attention in HIV-infected patients is poorly understood. Accordingly, the aim of the study was to identify whether the HIV-infected patients showed a specific attention network deficit or a general attentional impairment.

METHODS

We investigated 27 HIV-infected patients and 31 normal controls with the Attention Network Test (ANT).

RESULTS

The patients exhibited less efficient alerting network and executive network than controls. No significant difference was found in orienting network effect between groups. Our results also indicate a tendency for poorer efficiency on alerting attention and executive attention in patients with CD4 ≤ 200.

CONCLUSIONS

Our findings suggest that HIV-infected patients exhibited selective impairments of attention network of alerting and executive control. The link between lower CD4 T cell count and poorer attention network function imply the importance of starting antiretroviral therapy earlier to avoid irreversible neurocognitive impairment.

Reliability of White Matter Microstructural Changes in HIV Infection: Meta-Analysis and Confirmation

BACKGROUND

Diffusion tensor imaging has been widely used to measure HIV effects on white matter microarchitecture. While many authors have reported reduced fractional anisotropy and increased mean diffusivity in HIV, quantitative inconsistencies across studies are numerous.

PURPOSE

Our aim was to evaluate the consistency across studies of HIV effects on DTI measures and then examine the DTI reliability in a longitudinal seropositive cohort.

DATA SOURCES

Published studies and investigators.

STUDY SELECTION

The meta-analysis included 16 cross-sectional studies reporting fractional anisotropy and 12 studies reporting mean diffusivity in the corpus callosum.

DATA ANALYSIS

Random-effects meta-analysis was used to estimate study standardized mean differences and heterogeneity. DTI longitudinal reliability was estimated in seropositive participants studied before and 3 and 6 months after beginning treatment.

DATA SYNTHESIS

Meta-analysis revealed lower fractional anisotropy (standardized mean difference, -0.43; P < .001) and higher mean diffusivity (standardized mean difference, 0.44; P < .003) in seropositive participants. Nevertheless, between-study heterogeneity accounted for 58% and 66% of the observed variance (P < .01). In contrast, the longitudinal cohort fractional anisotropy was higher and mean diffusivity was lower in seropositive participants (both, P < .001), and fractional anisotropy and mean diffusivity measures were very stable during 6 months, with intraclass correlation coefficients all >0.96.

LIMITATIONS

Many studies pooled participants with varying treatments, ages, and disease durations.

CONCLUSIONS

HIV effects on WM microstructure had substantial variations that could result from acquisition, processing, or cohort-selection differences. When acquisition parameters and processing were carefully controlled, the resulting DTI measures did not show high temporal variation. HIV effects on WM microstructure may be age-dependent. The high longitudinal reliability of DTI WM microstructure measures makes them promising disease-activity markers.

A Gap in Time: Extending our Knowledge of Temporal Processing Deficits in the HIV-1 Transgenic Rat

Approximately 50 % of HIV-1 seropositive individuals develop HIV-1 associated neurocognitive disorders (HAND), which commonly include alterations in executive functions, such as inhibition, set shifting, and complex problem solving. Executive function deficits in HIV-1 are fairly well characterized, however, relatively few studies have explored the elemental dimensions of neurocognitive impairment in HIV-1. Deficits in temporal processing, caused by HIV-1, may underlie the symptoms of impairment in higher level cognitive processes. Translational measures of temporal processing, including cross-modal prepulse inhibition (PPI), gap-prepulse inhibition (gap-PPI), and gap threshold detection, were studied in mature (ovariectomized) female HIV-1 transgenic (Tg) rats, which express 7 of the 9 HIV-1 genes constitutively throughout development. Cross-modal PPI revealed a relative insensitivity to the manipulation of interstimulus interval (ISI) in HIV-1 Tg animals in comparison to control animals, extending previously reported temporal processing deficits in HIV-1 Tg rats to a more advanced age, suggesting the permanence of temporal processing deficits. In gap-PPI, HIV-1 Tg animals exhibited a relative insensitivity to the manipulation of ISI in comparison to control animals. In gap-threshold detection, HIV-1 Tg animals displayed a profound differential sensitivity to the manipulation of gap duration. Presence of the HIV-1 transgene was diagnosed with 91.1 % accuracy using gap threshold detection measures. Understanding the generality and permanence of temporal processing deficits in the HIV-1 Tg rat is vital to modeling neurocognitive deficits observed in HAND and provides a key target for the development of a diagnostic screening tool.

HMGB1/anti-HMGB1 antibodies define a molecular signature of early stages of HIV-Associated Neurocognitive Isorders (HAND)

BACKGROUND

HIV-associated neurocognitive disorders (HAND) persist in the post-HAART era, characterized by asymptomatic neurocognitive impairment (ANI) and mild neurocognitive disorders (MND). High mobility group box 1 (HMGB1) is a non-histone chromosomal protein widely expressed in the nucleus of all eukaryotic cells, including brain cells, which acts as a potent proinflammatory cytokine when actively secreted from immune cells. Recent reports suggested that HMGB1 acts on microglial cells to promote neuroinflammation. In this study, our aim was to determine whether HMGB1 is involved in HAND, but also to identify early new markers of neurological impairment in HIV-infected patients.

METHODS

CSF and serum were collected from 103 HIV-1-infected patients enrolled in Neuradapt, a prospective study of the prevalence of HAND in HIV-1 infected patients at Nice University Hospital. Stored fluids were assessed for immunological, virological, and brain metabolite parameters. In addition to HIV RNA and DNA measurements, expression of T-cell surface markers of activation (CD38 and HLA-DR) was analyzed on whole blood. Concentration of 27 cytokines and chemokines was measured using multiplex bead assays on serum and CSF. Concentration of HMGB1 and anti-HMGB1 IgG autoantibodies were also measured on the same samples. Changes in cerebral metabolites N-acetyl aspartate (NAA), Choline (Cho) and creatinine (Cr) were assessed by magnetic resonance microscopy (MRS).

RESULTS

Clinical, virological and immunological characteristics were comparable between HAND (n = 30) and no HAND (n = 73) patients, except the absolute numbers of CD8⁺ T cells, which were higher in patients with HAND. Among the 29 molecules tested, only 4 of them were significantly upregulated in the CSF from HAND patients as compared to healthy donors i.e. HMGB1, anti-HMGB1 IgG antibodies, IP-10 and MCP1. CSF HMGB1 levels were positively correlated with HIV-1 DNA in aviremic HAND patients, suggesting a positive impact of HMGB1 on HIV reservoirs. Moreover, in contrast to NAA/Cr and Cho/NAA ratios, circulating anti-HMGB1 IgG antibody levels could discriminate patients with no HAND from patients with no HAND and a single deficit (average ROC-AUC = 0.744, p = 0.03 for viremic patients), thus enabling the identification of a very early stage of neurocognitive impairment.

CONCLUSION

We report that brain injury in chronically HIV-infected patients on stable HAART is strongly associated with persistent CNS inflammation, which is correlated with increased levels of HMGB1 and anti-HMGB1 IgG in the CSF. Moreover, we identified circulating anti-HMGB1 IgG as a very early biomarker of neurological impairment in patients without HAND. These results might have important implication for the identification of patients who are at high risk of developing neurological disorders.

A comparison of the sensitivity, stability, and reliability of three diagnostic schemes for HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) occur in approximately 50% of HIV-infected individuals, yet available diagnostic criteria yield varying prevalence rates. This study examined the frequency, reliability, and sensitivity to everyday functioning problems of three HAND diagnostic criteria (DSM-5, Frascati, Gisslén). Participants included 361 adults with HIV disease and 199 seronegative adults. Neurocognitive status as defined by each of the three diagnostic systems was determined via a comprehensive neuropsychological battery. Everyday functioning was evaluated through self-report and clinician ratings. Results of logistic regressions revealed an association of HIV serostatus with Frascati-defined neurocognitive impairment (p = .027, OR = 1.7[1.1, 2.7]), but not DSM-5 or Gisslén-defined criteria (ps > .05). Frascati and DSM-5 criteria demonstrated agreement on 71% of observations, Frascati and Gisslén showed agreement on 80%, and DSM-5 and Gisslén criteria showed agreement on 46%, though reliability across the three criteria was poor. Only Frascati-defined neurocognitive impairment significantly predicted everyday functioning problems (p = .002, OR = 2.3[1.4, 3.8]). However, when both neurocognitive and complaint criteria were considered, the DSM-5 guidelines demonstrated significant relationships to everyday functioning, serostatus, and also increased reliability overtime compared to neurocognitive criteria alone (all ps < .05). A subset (n = 118) of the HIV+ group was assessed again after 14.0 (2.2) months. DSM-5 criteria evidenced significantly higher rates of incident neurocognitive disorder compared to both Frascati (p = .003) and Gisslén (p = .021) guidelines, while there were fewer remitting neurocognitive disorder diagnoses when Gisslén criteria were applied to the study sample compared to Frascati (p = .04). Future studies should aim to identify gold standard biological markers (e.g., neuropathology) and clinical outcomes associated with specific diagnostic criteria.

Temporal processsing demands in the HIV-1 transgenic rat: Amodal gating and implications for diagnostics

Despite the success of combination antiretroviral therapy (cART), approximately 50% of HIV-1 seropositive individuals develop HIV-1 associated neurocognitive disorders (HAND). Unfortunately, point-of-care screening tools for HAND lack sensitivity and specificity, especially in low-resource countries. Temporal processing deficits have emerged as a critical underlying dimension of neurocognitive impairments observed in HIV-1 and may provide a key target for the development of a novel point-of-care screening tool for HAND. Cross-modal prepulse inhibition (PPI; i.e., auditory, visual, or tactile prepulse stimuli) and gap-prepulse inhibition (gap-PPI; i.e., auditory, visual or tactile prepulse stimuli), two translational experimental paradigms, were used to assess the nature of temporal processing deficits in the HIV-1 transgenic (Tg) rat. Cross-modal PPI revealed a relative insensitivity to the manipulation of interstimulus interval (ISI) in HIV-1 Tg rats in comparison to controls, regardless of prestimulus modality. Gap-PPI revealed differential sensitivity to the manipulation of ISI, independent of modality, in HIV-1 Tg rats in comparison to control animals. Manipulation of context (i.e., concurrent visual or tactile stimulus) in auditory PPI revealed a differential sensitivity in HIV-1 Tg animals compared to controls. The potential utility of amodal temporal processing deficits as an innovative point-of-care screening tool was explored using a discriminant function analysis, which diagnosed the presence of the HIV-1 transgene with 97.4% accuracy. Thus, the presence of amodal temporal processing deficits in the HIV-1 Tg rat supports the hypothesis of a central temporal processing deficit in HIV-1 seropositive individuals, heralding an opportunity for the development of a point-of-care screening tool for HAND.

Fate of microglia during HIV-1 infection: From activation to senescence?

Microglia support productive human immunodeficiency virus type 1 (HIV-1) infection and disturbed microglial function could contribute to the development of HIV-associated neurocognitive disorders (HAND). Better understanding of how HIV-1 infection and viral protein exposure modulate microglial function during the course of infection could lead to the identification of novel therapeutic targets for both the eradication of HIV-1 reservoir and treatment of neurocognitive deficits. This review first describes microglial origins and function in the normal central nervous system (CNS), and the changes that occur during aging. We then critically discuss how HIV-1 infection and exposure to viral proteins such as Tat and gp120 affect various aspects of microglial homeostasis including activation, cellular metabolism and cell cycle regulation, through pathways implicated in cellular stress responses including p38 mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB). We thus propose that the functions of human microglia evolve during both healthy and pathological aging. Aging-associated dysfunction of microglia comprises phenotypes resembling cellular senescence, which could contribute to cognitive impairments observed in various neurodegenerative diseases. In addition, microglia seems to develop characteristics that could be related to cellular senescence post-HIV-1 infection and after exposure to HIV-1 viral proteins. However, despite its potential role as a component of HAND and likely other neurocognitive disorders, microglia senescence has not been well characterized and should be the focus of future studies, which could have high translational relevance. GLIA 2017;65:431-446.

Latent toxoplasmosis is associated with neurocognitive impairment in young adults with and without chronic HIV infection

We evaluated the impact of latent toxoplasmosis (LT) on neurocognitive (NC) and neurobehavioural functioning in young adults with and without chronic HIV infection, using a standardised NC test battery, self-reported Beck Depression Inventory, Frontal System Behavior Scale, MINI-International Neuropsychiatric Interview and risk-assessment battery. 194 young adults (median age 24years, 48.2% males) with chronic HIV infection (HIV+) since childhood and 51 HIV seronegative (HIV-) participants were included. HIV+ individuals had good current immunological status (median CD4: 479 cells/μl) despite a low CD4 nadir (median: 93 cells/μl). LT (positive anti-Toxoplasma IgG antibodies) was present in one third of participants. The impairment rates in the HIV- with and without Toxo were not significantly different (p=0.17). However, we observed an increasing trend (p<0.001) in impairment rates with HIV and LT status: HIV-/LT- (6.1%); HIV-/LT+ (22%), HIV+/LT- (31%), HIV+/LT+ (49%). In a multivariable analysis using the entire study group there were main effects on cognition for HIV and also for LT. Within the HIV+ group LT was associated with worse performance globally (p=0.006), in memory (p=0.009), speed of information processing (p=0.01), verbal (p=0.02) and learning (p=0.02) domains. LT was not associated with depressive symptoms, frontal systems dysfunction or risk behaviors in any of the groups. HIV participants with lower Toxoplasma antibody concentration had worse NC performance, with higher GDS values (p=0.03) and worse learning (p=0.002), memory (p=0.006), speed of information processing (p=0.01) T scores. Latent Toxoplasmosis may contribute to NC impairment in young adults, including those with and without chronic HIV infection.

A Comparison of Five Brief Screening Tools for HIV-Associated Neurocognitive Disorders in the USA and South Africa

Screening for HIV-associated neurocognitive disorders (HAND) is important to improve clinical outcomes. We compared the diagnostic sensitivity and specificity of the mini-mental state examination, International HIV dementia scale (IHDS), Montreal cognitive assessment, Simioni symptom questionnaire and cognitive assessment tool-rapid version (CAT-rapid) to a gold standard neuropsychological battery. Antiretroviral-experienced participants from Cape Town, South Africa, and Baltimore, USA, were recruited. The sensitivity and specificity of the five tools, as well as those of the combined IHDS and CAT-rapid, were established using 2 × 2 contingency tables and ROC analysis. More than a third (65165) had symptomatic HAND. In detecting HIV-D, the CAT-Rapid had good sensitivity (94 %) and weak specificity (52 %) (cut-point ≤10), while the IHDS showed fair sensitivity (68 %) and good specificity (86 %) (cut-point ≤10). The combined IHDS and CAT-rapid showed excellent sensitivity and specificity for HIV-D at a cut-off score of ≤16 (out of 20; 89 and 82 %). No tool was adequate in screening for any HAND. The combination IHDS and CAT-rapid tool appears to be a good screener for HIV-D but is only fairly sensitive and poorly specific in screening for any HAND. Screening for milder forms of HAND continues to be a clinical challenge.

Short Communication: Do Cytomegalovirus Antibody Levels Associate with Age-Related Syndromes in HIV Patients Stable on Antiretroviral Therapy?

HIV(+) persons stable on antiretroviral therapy (ART) face early onset of age-related diseases. This may arise from a high burden of cytomegalovirus (CMV). To address the role of CMV, we investigated univariate and multivariate associations between markers of systemic and endothelial inflammation, vascular damage, insulin resistance (IR), neurocognitive decline, and antibodies reactive with CMV. In this study, HIV(+) participants (n = 91) aged >45 years with <50 copies HIV RNA/ml plasma after >2 years on ART were assessed for cardiovascular risk (the D:A:D algorithm), type II diabetes (the HOMA-IR index), and neurocognitive performance. Blood samples were assayed for lipids, T cells, insulin, glucose, C-reactive protein, CX3CL1, sTNF-R1, total immunoglobulin G (IgG), and antibodies reactive with CMV lysate, glycoprotein B, or immediate-early-1. Levels of antibodies detected with the three antigens were tightly correlated. Levels of CMV lysate antibody were higher in patients than in age-matched healthy controls and reflected their nadir CD4 T-cell count (p = .001), total IgG (p = .02), and age (p = .08). Levels of CMV lysate antibody correlated with D:A:D score (p = .04), neurocognitive performance (p = .045), and fasting insulin (p = .02). In multivariable analyses, some associations reflected the effect of age, but CMV lysate antibody and CD8 T-cell counts were significant predictors of the HOMA-IR index (R(2) = 0.09, p = .01) independent of age. We conclude that associations between levels of CMV antibodies, cardiovascular risk, and neurocognitive health in HIV(+) patients stable on ART are moderated by age-associated increases in response to CMV, while CMV antibodies may be independently linked with IR.

Expression of gp120 in mice evokes anxiety behavior: Co-occurrence with increased dendritic spines and brain-derived neurotrophic factor in the amygdala

Human immunodeficiency virus type 1 (HIV) infection of the brain produces cognitive and motor disorders. In addition, HIV positive individuals exhibit behavioral alterations, such as apathy, and a decrease in spontaneity or emotional responses, typically seen in anxiety disorders. Anxiety can lead to psychological stress, which has been shown to influence HIV disease progression. These considerations underscore the importance of determining if anxiety in HIV is purely psychosocial, or if by contrast, there are the molecular cascades associated directly with HIV infection that may mediate anxiety. The present study had two goals: (1) to determine if chronic exposure to viral proteins would induce anxiety-like behavior in an animal model and (2) to determine if this exposure results in anatomical abnormalities that could explain increased anxiety. We have used gp120 transgenic mice, which display behavior and molecular deficiencies similar to HIV positive subjects with cognitive and motor impairments. In comparison to wild type mice, 6 months old gp120 transgenic mice demonstrated an anxiety like behavior measured by open field, light/dark transition task, and prepulse inhibition tests. Moreover, gp120 transgenic mice have an increased number of spines in the amygdala, as well as higher levels of brain-derived neurotrophic factor and tissue plasminogen activator when compared to age-matched wild type. Our data support the hypothesis that HIV, through gp120, may cause structural changes in the amygdala that lead to maladaptive responses to anxiety.

Evolution of changes in cognitive function after the initiation of antiretroviral therapy

BACKGROUND

Cognitive function is reported to improve after the initiation of combination antiretroviral therapy (cART). Data on the evolution of such changes are limited. We assessed the dynamics of changes in cognitive parameters, in HIV-positive subjects initiating cART.

METHODS

Cognitive function in seven domains was evaluated for HIV-infected patients without clinically significant cognitive impairment prior to the initiation of cART, and 24 and 48 weeks after. Cognitive scores were transformed using standardised z-scores according to the pooled baseline standard deviation. Global, speed, and accuracy composite z-scores were calculated with changes calculated using a paired t test.

RESULTS

In 14 subjects, change in global cognitive z-scores from baseline was by 0.08 at week 24 (p = 0.59) and 0.15 at week 48 (p = 0.43). Change in composite speed and accuracy z-scores from baseline at weeks 24/48 were 0.07/0.05 (p = 0.45/0.82) and 0.13/0.23 (p = 0.47/0.45), respectively. In two of the cognitive domains assessing speed (learning and monitoring time), a continued improvement from baseline to weeks 24 and 48 was observed (changes of 0.06-0.08 and 0.10-0.19, respectively), whereas in two domains (detection and identification) an initial improvement at week 24 (changes of -0.10 and 0.04 from baseline, respectively) was followed by a deterioration in score at week 48 (changes of -0.12 and -0.08 from baseline, respectively). None of these changes were statistically significant.

CONCLUSIONS

A trend for improvement in cognitive function was observed in naïve HIV-positive patients starting cART. The dynamics of this improvement differed both between cognitive domains and the time-points assessed.

Lipid Management in Human Immunodeficiency Virus

The development and use of antiretroviral medications to treat patients infected with human immunodeficiency virus (HIV) has dramatically changed the course of this disease from one that was fatal to a chronic and more manageable condition. Recommendations and guidelines for the general population are presented in this review with suggestions as to how they may be applied to this patient population. Issues for which there is little or no information available are noted to highlight the many gaps in our knowledge regarding diagnosis and management of dyslipidemia for patients living with HIV.

Gene Expression in HIV-Associated Neurocognitive Disorders: A Meta-Analysis

OBJECTIVES

To identify differentially expressed (DE) genes in HIV-associated neurocognitive disorders (HAND) patients in comparison with HIV-infected patients without HAND and controls.

DESIGN

A meta-analysis of publicly available gene expression data from HIV postmortem brain tissue studies.

METHODS

We selected studies using clearly defined inclusion and exclusion criteria. Within study data preprocessing and individual analyses were performed for each brain region. The following meta-analytic methods were applied: combining P values, combining effect sizes with and without a permutation method. The DE genes were defined with a false discovery rate less than 5% using Benjamini-Hochberg method.

RESULTS

Our meta-analysis on 3 studies encompasses analyses of over 48 postmortem brains [25 HAND, 7 HIV encephalitis (HIVE), 8 HIV-infected patients, and 8 controls]. Overall, 411 genes in white matter were DE in HAND with HIVE patients when comparing with controls. Of these, 94 genes were significantly expressed in all statistical methods. These 94 genes participate in significant pathways such as immune system, interferon response, or antigen presentation. Sixty-six of the 94 genes were significantly upregulated with log2 intensities greater than 2-fold. Strong examples of the highly upregulated genes were PSMB8-AS1, APOL6, TRIM69, PSME1, CTSB, HLA-E, GPNMB, UBE2L6, PSME2, NET1, CAPG, B2M, RPL38, GBP1, and PLSCR1. Only BTN3A2 was expressed in HAND with HIVE patients as compared with HAND patients without HIVE.

CONCLUSION

A number of genes were DE in our meta-analysis that were not identified in the individual analyses. The meta-analytic approach has increased statistical power for identifying DE genes in HAND.

Neuropsychological Impairment in Acute HIV and the Effect of Immediate Antiretroviral Therapy

OBJECTIVE

To investigate neuropsychological performance (NP) during acute HIV infection (AHI) before and after combination antiretroviral therapy (cART).

DESIGN

Prospective study of Thai AHI participants examined at 3 and 6 months after initiation of cART.

METHODS

Thirty-six AHI participants were evaluated pre-cART at median 19 days since HIV exposure and 3 and 6 months after cART with the Grooved Pegboard test, Color Trails 1 & 2 (CT1, CT2), and Trail Making Test A. Raw scores were standardized to 251 age- and education-matched HIV-uninfected Thais. To account for learning effects, change in NP performance was compared with that of controls at 6 months. Analyses included multivariable regression, nonparametric repeated measures analysis of variance, and Mann-Whitney U test.

RESULTS

Baseline NP scores for the AHI group were within normal range (z-scores range: -0.26 to -0.13). NP performance improved on CT1, CT2, and Trail Making Test A in the initial 3 months (P < 0.01) with no significant change during the last 3 months. Only improvement in CT1 was greater than that seen in controls at 6 months (P = 0.018). Participants who performed >1 SD below normative means on ≥2 tests (n = 8) exhibited higher baseline cerebrospinal fluid HIV RNA (P = 0.047) and had no improvement after cART.

CONCLUSIONS

Most AHI individuals had normal NP performance, and early cART slightly improved their psychomotor function. However, approximately 25% had impaired NP performance, which correlated with higher cerebrospinal fluid HIV RNA, and these abnormalities were not reversed by early cART possibly indicating limited reversibility of cognitive impairment in a subset of AHI individuals.