Incidence and prevalence of neurological disorders associated with HIV since the introduction of highly active antiretroviral therapy (HAART)

Contribution of CNS and extra-CNS infections to neurodegeneration: a narrative review

Central nervous system infections have been suggested as a possible cause for neurodegenerative diseases, particularly sporadic cases. They trigger neuroinflammation which is considered integrally involved in neurodegenerative processes. In this review, we will look at data linking a variety of viral, bacterial, fungal, and protozoan infections to Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis and unspecified dementia. This narrative review aims to bring together a broad range of data currently supporting the involvement of central nervous system infections in the development of neurodegenerative diseases. The idea that no single pathogen or pathogen group is responsible for neurodegenerative diseases will be discussed. Instead, we suggest that a wide range of susceptibility factors may make individuals differentially vulnerable to different infectious pathogens and subsequent pathologies.

Kynurenic acid blunts A1 astrocyte activation against neurodegeneration in HIV-associated neurocognitive disorders

Despite extensive astrocyte activation in patients suffering from HIV-associated neurocognitive disorders (HAND), little is known about the contribution of astrocytes to HAND neuropathology. Here, we report that the robust activation of neurotoxic astrocytes (A1 astrocytes) in the CNS promotes neuron damage and cognitive deficits in HIV-1 gp120 transgenic mice. Notably, knockout of α7 nicotinic acetylcholine receptors (α7nAChR) blunted A1 astrocyte responses, ultimately facilitating neuronal and cognitive improvement in the gp120tg mice. Furthermore, we provide evidence that Kynurenic acid (KYNA), a tryptophan metabolite with α7nAChR inhibitory properties, attenuates gp120-induced A1 astrocyte formation through the blockade of α7nAChR/JAK2/STAT3 signaling activation. Meanwhile, compared with gp120tg mice, mice fed with tryptophan showed dramatic improvement in cognitive performance, which was related to the inhibition of A1 astrocyte responses. These initial and determinant findings mark a turning point in our understanding of the role of α7nAChR in gp120-mediated A1 astrocyte activation, opening up new opportunities to control neurotoxic astrocyte generation through KYNA and tryptophan administration.

17⍺-Estradiol Protects against HIV-1 Tat-Induced Endolysosome Dysfunction and Dendritic Impairments in Neurons

HIV-1 Tat continues to play an important role in the development of HIV-associated neurocognitive disorders (HAND), which persist in 15-55% of people living with HIV even with virological control. In the brain, Tat is present on neurons, where Tat exerts direct neuronal damaging effects by, at least in part, disrupting endolysosome functions, a pathological feature present in HAND. In this study, we determined the protective effects of 17α-estradiol (17αE2), the predominant form of estrogen in the brain, against Tat-induced endolysosome dysfunction and dendritic impairment in primary cultured hippocampal neurons. We demonstrated that pre-treatment with 17αE2 protected against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Estrogen receptor alpha (ERα) knockdown impairs the ability of 17αE2 to protect against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Furthermore, over-expressing an ERα mutant that fails to localize on endolysosomes impairs 17αE2's protective effects against Tat-induced endolysosome dysfunction and reduction in dendritic spine density. Our findings demonstrate that 17αE2 protects against Tat-induced neuronal injury via a novel ERα-mediated and endolysosome-dependent pathway, and such a finding might lead to the development of novel adjunct therapeutics against HAND.

Physiological Corticosterone Attenuates gp120-Mediated Microglial Activation and Is Associated with Reduced Anxiety-Like Behavior in gp120-Expressing Mice

Despite the benefits of combinatorial antiretroviral therapies (cART), virotoxic HIV proteins are still detectable within the central nervous system. Approximately half of all cART-treated patients contend with neurological impairments. The mechanisms underlying these effects likely involve virotoxic HIV proteins, including glycoprotein 120 (gp120). Glycoprotein-120 is neurotoxic due to its capacity to activate microglia. Corticosterone has been found to attenuate neuronal death caused by gp120-induced microglial cytokine production in vitro. However, the concentration-dependent effects of corticosterone on microglial activation states and the associated behavioral outcomes are unclear. Herein, we conducted parallel in vitro and in vivo studies to assess gp120-mediated effects on microglial activation, motor function, anxiety- and depression-like behavior, and corticosterone's capacity to attenuate these effects. We found that gp120 activated microglia in vitro, and corticosterone attenuated this effect at an optimal concentration of 100 nM. Transgenic mice expressing gp120 demonstrated greater anxiety-like behavior on an elevated plus maze, and a greater duration of gp120 exposure was associated with motor deficits and anxiety-like behavior. Circulating corticosterone was lower in gp120-expressing males and diestrous females. Greater circulating corticosterone was associated with reduced anxiety-like behavior. These findings may demonstrate a capacity for glucocorticoids to attenuate gp120-mediated neuroinflammation and anxiety-like behavior.

Investigating neurological symptoms of infectious diseases like COVID-19 leading to a deeper understanding of neurodegenerative disorders such as Parkinson's disease

Apart from common respiratory symptoms, neurological symptoms are prevalent among patients with COVID-19. Research has shown that infection with SARS-CoV-2 accelerated alpha-synuclein aggregation, induced Lewy-body-like pathology, caused dopaminergic neuron senescence, and worsened symptoms in patients with Parkinson's disease (PD). In addition, SARS-CoV-2 infection can induce neuroinflammation and facilitate subsequent neurodegeneration in long COVID, and increase individual vulnerability to PD or parkinsonism. These findings suggest that a post-COVID-19 parkinsonism might follow the COVID-19 pandemic. In order to prevent a possible post-COVID-19 parkinsonism, this paper reviewed neurological symptoms and related findings of COVID-19 and related infectious diseases (influenza and prion disease) and neurodegenerative disorders (Alzheimer's disease, PD and amyotrophic lateral sclerosis), and discussed potential mechanisms underlying the neurological symptoms and the relationship between the infectious diseases and the neurodegenerative disorders, as well as the therapeutic and preventive implications in the neurodegenerative disorders. Infections with a relay of microbes (SARS-CoV-2, influenza A viruses, gut bacteria, etc.) and prion-like alpha-synuclein proteins over time may synergize to induce PD. Therefore, a systematic approach that targets these pathogens and the pathogen-induced neuroinflammation and neurodegeneration may provide cures for neurodegenerative disorders. Further, antiviral/antimicrobial drugs, vaccines, immunotherapies and new therapies (e.g., stem cell therapy) need to work together to treat, manage or prevent these disorders. As medical science and technology advances, it is anticipated that better vaccines for SARS-CoV-2 variants, new antiviral/antimicrobial drugs, effective immunotherapies (alpha-synuclein antibodies, vaccines for PD or parkinsonism, etc.), as well as new therapies will be developed and made available in the near future, which will help prevent a possible post-COVID-19 parkinsonism in the 21st century.

Shock and kill within the CNS: A promising HIV eradication approach?

The most studied HIV eradication approach is the "shock and kill" strategy, which aims to reactivate the latent reservoir by latency reversing agents (LRAs) and allowing elimination of these cells by immune-mediated clearance or viral cytopathic effects. The CNS is an anatomic compartment in which (persistent) HIV plays an important role in HIV-associated neurocognitive disorder. Restriction of the CNS by the blood-brain barrier is important for maintenance of homeostasis of the CNS microenvironment, which includes CNS-specific cell types, expression of transcription factors, and altered immune surveillance. Within the CNS predominantly myeloid cells such as microglia and perivascular macrophages are thought to be a reservoir of persistent HIV infection. Nevertheless, infection of T cells and astrocytes might also impact HIV infection in the CNS. Genetic adaptation to this microenvironment results in genetically distinct, compartmentalized viral populations with differences in transcription profiles. Because of these differences in transcription profiles, LRAs might have different effects within the CNS as compared with the periphery. Moreover, reactivation of HIV in the brain and elimination of cells within the CNS might be complex and could have detrimental consequences. Finally, independent of activity on latent HIV, LRAs themselves can have adverse neurologic effects. We provide an extensive overview of the current knowledge on compartmentalized (persistent) HIV infection in the CNS and on the "shock and kill" strategy. Subsequently, we reflect on the impact and promise of the "shock and kill" strategy on the elimination of persistent HIV in the CNS.

The choroid plexus and its role in the pathogenesis of neurological infections

The choroid plexus is situated at an anatomically and functionally important interface within the ventricles of the brain, forming the blood-cerebrospinal fluid barrier that separates the periphery from the central nervous system. In contrast to the blood–brain barrier, the choroid plexus and its epithelial barrier have received considerably less attention. As the main producer of cerebrospinal fluid, the secretory functions of the epithelial cells aid in the maintenance of CNS homeostasis and are capable of relaying inflammatory signals to the brain. The choroid plexus acts as an immunological niche where several types of peripheral immune cells can be found within the stroma including dendritic cells, macrophages, and T cells. Including the epithelia cells, these cells perform immunosurveillance, detecting pathogens and changes in the cytokine milieu. As such, their activation leads to the release of homing molecules to induce chemotaxis of circulating immune cells, driving an immune response at the choroid plexus. Research into the barrier properties have shown how inflammation can alter the structural junctions and promote increased bidirectional transmigration of cells and pathogens. The goal of this review is to highlight our foundational knowledge of the choroid plexus and discuss how recent research has shifted our understanding towards viewing the choroid plexus as a highly dynamic and important contributor to the pathogenesis of neurological infections. With the emergence of several high-profile diseases, including ZIKA and SARS-CoV-2, this review provides a pertinent update on the cellular response of the choroid plexus to these diseases. Historically, pharmacological interventions of CNS disorders have proven difficult to develop, however, a greater focus on the role of the choroid plexus in driving these disorders would provide for novel targets and routes for therapeutics.

Childhood trauma and genetic variation in the DAT 40-bp VNTR contribute to HIV-associated neurocognitive disorders

HIV/AIDS is a major public health burden in South Africa, currently affecting an estimated 13.5% of the population. Despite improved access to antiretroviral therapies, HIV-associated neurocognitive disorders (HAND), characterised by a spectrum of neurocognitive impairment, emotional disturbances and motor abnormalities, continue to persist. Gene-environment interactions contribute to HAND pathophysiology and previous research has identified childhood trauma as an environmental risk factor. Dopaminergic signalling in the prefrontal cortex plays a key role in cognitive function. Thus, variants in genes encoding the dopamine transporter (DAT) and catechol-O-methyltransferase (COMT), which are responsible for dopamine transport and metabolism, could represent genetic risk factors for HAND. This study investigated whether the DAT variable number of tandem repeats (VNTR) and COMT Val158Met (rs4680) polymorphisms are associated with longitudinal change in cognitive function in the context of childhood trauma and HIV. Participants (n = 49 HIV-negative and n = 64 HIV-positive women) completed the Childhood Trauma Questionnaire - Short Form (CTQ-SF) and provided blood for genetic analyses. Global cognitive scores were generated from baseline and one-year follow-up assessments. Following polymerase chain reaction, genotypes were determined using gel electrophoresis and confirmed by Sanger sequencing. Baseline global cognitive scores, genotype, HIV status and CTQ-SF scores were regressed on one-year global cognitive scores in regression models. Analysis of variance was used to examine the effect of including predictor variable interactions on model fit. HIV seropositivity was associated with poorer cognitive performance at one-year follow-up (p = 2.46 ×10-4). The combination of HIV and DAT 10-repeat homozygosity (DAT 10/10) was associated with reduced global cognitive scores in longitudinal models (p = 0.010). Including the interaction between DAT 10/10, childhood trauma, and HIV explained significantly more of the variance in longitudinal cognitive scores (p = 0.008). There were no significant associations with the COMT genotype. Our research indicates that childhood trauma and genetic variation in DAT contribute toward the aetiology of HAND. Future studies in larger cohorts are warranted to verify these results.

HIV Dementia: A Bibliometric Analysis and Brief Review of the Top 100 Cited Articles

Dementia is a syndrome of cognitive impairment that affects an individual’s ability to live independently. The number of people living with dementia worldwide in 2015 was estimated at 47.47 million. The American Academy of Neurology (AAN) criteria for human immunodeficiency virus (HIV)-associated dementia (HAD) require an acquired abnormality in at least two cognitive (non-motor) domains and either an abnormality in motor function or specified neuropsychiatric/psychosocial domains. HIV is the most common cause of dementia below 60 years of age.

Citation frequencies are commonly used to assess the scholarly impact of any scientific publication in bibliometric analyses. It helps depict areas of higher interest in terms of research frequency and trends of citations in the published literature and identify under-explored domains of any field, providing useful insight and guidance for future research avenues. We used the database “Web of Science” (WOS) to search for the top 100 cited articles on HIV-associated dementia. The keywords “HIV dementia” and “HIV-associated neurocognitive disorders” (HAND) were used. The list was generated by two authors after excluding articles not pertaining to HIV dementia. The articles were then assigned to authors to extract data to make tables and graphical representations. Finally, the manuscript was organized and written describing the findings of the bibliometric study.

These 100 most cited articles on HIV dementia were published between years 1986 and 2016. The highest number of the articles was from 1999 (n=9). The year 1993-2007 contributed consistently two publications to the list. The articles are from 42 journals, and among them, the Annals of Neurology (n=16) and the Journal of Neurology (n=15) published most of the articles. Justin C. McArthur with 25 publications contributed the highest number of papers to the list by any author. The USA collaborated in the highest number of publications (n=87). American institutes were leading the list with the most publications. The Johns Hopkins University collaborated on 37 papers. The most widely studied aspect of HIV dementia was pathogenesis. Incidence and prevalence, clinical features, and pre- and post-highly active antiretroviral therapy (HAART) era were also discussed in the articles.

Beyond America, the research should be expanded to low-income countries and those affected more by HIV. Therefore, other countries and their institutes should participate more in HIV-associated dementia research. Anticipating the rising resistance to existing antiretrovirals, we should develop new therapeutic options. There is room for research in many aspects of HIV dementia care.

Impact of HIV-associated cognitive impairment on functional independence, frailty and quality of life in the modern era: a meta-analysis

HIV-associated neurocognitive disorder (HAND) is an important sequela of HIV infection. Combined antiretroviral therapy (cART) has improved the health outcomes of many people living with HIV but has given rise to a less severe but limiting form of HAND. The study aimed to evaluate the impact of HAND on medication adherence, activities of daily living (ADL), quality of life and frailty. This systematic review adheres to the guidelines for Preferred Reporting Items for Systematic Reviews and Meta-Analyses. We searched MEDLINE, PubMed, CINAHL, Academic Search Complete, and PsycINFO online databases. Studies were included if they examined the relationship between HAND and medication adherence, ADL, quality of life and frailty, and were conducted between 1997 and 2021. We used a random-effects meta-analysis model to assess the impact of HAND on outcome variables. Forty papers, totaling 11,540 participants, were included in the narrative and quantitative syntheses. Cognitive impairment was associated with poorer medication adherence (r = 0.601, CI 0.338 to 0.776, p = 0.001, I² = 94.66). Cognitive impairment did not influence ADL (r = 0.167, CI-0.215 to 0.505, p = 0.393) and quality of life (r = 0.244, CI 0.117 to 0.548, p = 0.182). In the cART era, HAND appears to be associated with adherence to medication, which may influence future health outcomes. In PLWHIV who are adherent to cART, cognitive impairment does not appear to interfere with ADL and quality of life.

Epigenome-wide epidemiologic studies of human immunodeficiency virus infection, treatment, and disease progression

Despite significant advances in the treatment and care of people with HIV (PWH), several challenges remain in our understanding of disease pathogenesis to improve patient care. HIV infection can modify the host epigenome and as such can impact disease progression, as well as the molecular processes driving non-AIDS comorbidities in PWH. Epigenetic epidemiologic studies including epigenome-wide association studies (EWAS) offer a unique set of tools to expand our understanding of HIV disease and to identify novel strategies applicable to treatment and diagnosis in this patient population. In this review, we summarize the current state of knowledge from epigenetic epidemiologic studies of PWH, identify the main challenges of this approach, and highlight future directions for the field. Emerging epigenetic epidemiologic studies of PWH can expand our understanding of HIV infection and health outcomes, improve scientific validity through collaboration and replication, and increase the coverage of diverse populations affected by the global HIV pandemic. Through this review, we hope to highlight the potential of EWAS as a tool for HIV research and to engage more investigators to explore its application to important research questions.

Endolysosome Localization of ERα Is Involved in the Protective Effect of 17α-Estradiol against HIV-1 gp120-Induced Neuronal Injury

Neurotoxic HIV-1 viral proteins contribute to the development of HIV-associated neurocognitive disorder (HAND), the prevalence of which remains high (30-50%) with no effective treatment available. Estrogen is a known neuroprotective agent; however, the diverse mechanisms of estrogen action on the different types of estrogen receptors is not completely understood. In this study, we determined the extent to which and mechanisms by which 17α-estradiol (17αE2), a natural less-feminizing estrogen, offers neuroprotection against HIV-1 gp120-induced neuronal injury. Endolysosomes are important for neuronal function, and endolysosomal dysfunction contributes to HAND and other neurodegenerative disorders. In hippocampal neurons, estrogen receptor α (ERα) is localized to endolysosomes and 17αE2 acidifies endolysosomes. ERα knockdown or overexpressing an ERα mutant that is deficient in endolysosome localization prevents 17αE2-induced endolysosome acidification. Furthermore, 17αE2-induced increases in dendritic spine density depend on endolysosome localization of ERα. Pretreatment with 17αE2 protected against HIV-1 gp120-induced endolysosome deacidification and reductions in dendritic spines; such protective effects depended on endolysosome localization of ERα. In male HIV-1 transgenic rats, we show that 17αE2 treatment prevents the development of enlarged endolysosomes and reduction in dendritic spines. Our findings demonstrate a novel endolysosome-dependent pathway that governs the ERα-mediated neuroprotective actions of 17αE2, findings that might lead to the development of novel therapeutic strategies against HAND.SIGNIFICANCE STATEMENT Extranuclear presence of membrane-bound estrogen receptors (ERs) underlie the enhancing effect of estrogen on cognition and synaptic function. The estrogen receptor subtype ERα is present on endolysosomes and plays a critical role in the enhancing effects of 17αE2 on endolysosomes and dendritic spines. These findings provide novel insight into the neuroprotective actions of estrogen. Furthermore, 17αE2 protected against HIV-1 gp120-induced endolysosome dysfunction and reductions in dendritic spines, and these protective effects of 17αE2 were mediated via endolysosome localization of ERα. Such findings provide a rationale for developing 17αE2 as a therapeutic strategy against HIV-associated neurocognitive disorders.

HIV-Associated Neurotoxicity: The Interplay of Host and Viral Proteins

HIV-1 can incite activation of chemokine receptors, inflammatory mediators, and glutamate receptor-mediated excitotoxicity. The mechanisms associated with such immune activation can disrupt neuronal and glial functions. HIV-associated neurocognitive disorder (HAND) is being observed since the beginning of the AIDS epidemic due to a change in the functional integrity of cells from the central nervous system (CNS). Even with the presence of antiretroviral therapy, there is a decline in the functioning of the brain especially movement skills, noticeable swings in mood, and routine performance activities. Under the umbrella of HAND, various symptomatic and asymptomatic conditions are categorized and are on a rise despite the use of newer antiretroviral agents. Due to the use of long-lasting antiretroviral agents, this deadly disease is becoming a manageable chronic condition with the occurrence of asymptomatic neurocognitive impairment (ANI), symptomatic mild neurocognitive disorder, or HIV-associated dementia. In-depth research in the pathogenesis of HIV has focused on various mechanisms involved in neuronal dysfunction and associated toxicities ultimately showcasing the involvement of various pathways. Increasing evidence-based studies have emphasized a need to focus and explore the specific pathways in inflammation-associated neurodegenerative disorders. In the current review, we have highlighted the association of various HIV proteins and neuronal cells with their involvement in various pathways responsible for the development of neurotoxicity.

Distinguishing cytomegalovirus meningoencephalitis from other viral central nervous system infections

BACKGROUND

Hallmarks of cytomegalovirus (CMV) meningoencephalitis include fever, altered mental status, or meningismus with pleocytosis, elevated protein and hypoglycorrhachia on cerebrospinal fluid (CSF) analysis. Magnetic resonance imaging may show ventriculitis, ependymitis or periventricular enhancement. Studies are limited comparing clinical and laboratory characteristics to other viral etiologies.

OBJECTIVES

This multi-center, retrospective cohort analysis reviewed patients with CMV meningitis or encephalitis and compared clinical features, laboratory findings and outcomes to the most common viral causes of meningoencephalitis.

STUDY DESIGN

Patients with encephalitis or aseptic meningitis and detectable genetic material by polymerase chain reaction were identified. Clinical characteristics, laboratory findings and neuroimaging were collected from the electronic medical record. Data analysis was performed comparing CMV to other viral etiologies.

RESULTS

485 patients were evaluated and included cases of CMV (n = 36) which were compared with herpes simplex virus (n = 114), enterovirus (n = 207), varicella zoster virus (n = 41) and West Nile virus (n = 81). Human immunodeficiency virus (HIV) infection was seen more frequently in CMV infection compared with all other viral etiologies. Clinical presentations and CSF findings of other viral etiologies differ compared with CMV. Hypoglycorrhacia occurred more often with CMV compared with other viral pathogens. Outcomes were significantly worse compared with enterovirus, herpes simplex virus and varicella zoster virus but not West Nile virus.

CONCLUSIONS

CMV meningoencephalitis occurs most often in patients with HIV and encephalitis occurs more frequently than meningitis. Clinical and laboratory findings differ compared with other viral etiologies and can support consideration of CMV in the differential diagnosis of patients with meningoencephalitis.

Development of a novel in vitro primary human monocyte-derived macrophage model to study reactivation of HIV-1 transcription

Latent HIV reservoirs persist in people living with HIV despite effective antiretroviral therapy and contribute to rebound viremia upon treatment interruption. Macrophages are an important reservoir cell-type, but analysis of agents that modulate latency in macrophages is limited by lack of appropriate in vitro models. We therefore generated an experimental system to investigate this by purifying non-productively-infected human monocyte-derived macrophages (MDM) following in vitro infection with an M-tropic EGFP reporter HIV clone, and quantified activation of HIV transcription using live-cell fluorescence microscopy. The proportion of HIV-infected MDM was quantified by qPCR detection of HIV DNA, and GFP expression was validated as a marker of productive HIV infection by co-labelling of HIV Gag protein. HIV transcription spontaneously reactivated in latently-infected MDM at a rate of 0.22% ± 0.04 cells per day (mean ± SEM, n=10 independent donors), producing infectious virions able to infect heterologous T cells in coculture experiments, and both T cells and TZM-bl cells in a cell-free infection system using MDM culture supernatants. Polarization to an M1 phenotype with IFNγ + TNF resulted in a 2.3 fold decrease in initial HIV infection of MDM (p<0.001, n=8) and 1.4 fold decrease in spontaneous reactivation (p=0.025, n=6) whereas M2 polarization using IL-4 prior to infection led to a 1.6 fold decrease in HIV infectivity (p=0.028, n=8), but a 2.0 fold increase in the rate of HIV reactivation in latently-infected MDM (p=0.023, n=6). The latency reversing agents bryostatin and vorinostat, but not panobinostat, significantly induced HIV reactivation in latently infected MDM (p=0.031 and p=0.038, respectively, n=6). Importance: Agents which modulate latent HIV reservoirs in infected cells are of considerable interest to HIV cure strategies. The present study characterizes a robust, reproducible model enabling quantification of HIV reactivation in primary HIV-infected human MDM which is relatively insensitive to the monocyte donor source and hence suitable for evaluating latency modifiers in MDM. The rate of initial viral infection was greater than the rate of HIV reactivation, suggesting different mechanisms regulate these processes. HIV reactivation was sensitive to macrophage polarization, suggesting cellular and tissue environments influence HIV reactivation in different macrophage populations. Importantly, latently infected MDM showed different susceptibility to certain latency reversing agents known to be effective in T cells, indicating dedicated strategies may be required to target latently-infected macrophage populations in vivo.

Telomere Length Shortening in Microglia: Implication for Accelerated Senescence and Neurocognitive Deficits in HIV

The widespread use of combination antiretroviral therapy (cART) has led to the accelerated aging of the HIV-infected population, and these patients continue to have a range of mild to moderate HIV-associated neurocognitive disorders (HAND). Infection results in altered mitochondrial function. The HIV-1 viral protein Tat significantly alters mtDNA content and enhances oxidative stress in immune cells. Microglia are the immune cells of the central nervous system (CNS) that exhibit a significant mitotic potential and are thus susceptible to telomere shortening. HIV disrupts the normal interplay between microglia and neurons, thereby inducing neurodegeneration. HIV cART contributes to the inhibition of telomerase activity and premature telomere shortening in activated peripheral blood mononuclear cells (PBMC). However, limited information is available on the effect of cART on telomere length (TL) in microglia. Although it is well established that telomere shortening induces cell senescence and contributes to the development of age-related neuro-pathologies, the effect of HIV-Tat on telomere length in human microglial cells and its potential contribution to HAND are not well understood. It is speculated that in HAND intrinsic molecular mechanisms that control energy production underlie microglia-mediated neuronal injury. TL, telomerase and mtDNA expression were quantified in microglial cells using real time PCR. Cellular energetics were measured using the Seahorse assay. The changes in mitochondrial function were examined by Raman Spectroscopy. We have also examined TL in the PBMC obtained from HIV-1 infected rapid progressors (RP) on cART and those who were cART naïve, and observed a significant decrease in telomere length in RP on cART as compared to RP's who were cART naïve. We observed a significant decrease in telomerase activity, telomere length and mitochondrial function, and an increase in oxidative stress in human microglial cells treated with HIV Tat. Neurocognitive impairment in HIV disease may in part be due to accelerated neuro-pathogenesis in microglial cells, which is attributable to increased oxidative stress and mitochondrial dysfunction.

Early prediction of putamen imaging features in HIV-associated neurocognitive impairment syndrome

Background

To explore the correlation between the volume of putamen and brain cognitive impairment in patients with HIV and to predict the feasibility of early-stage HIV brain cognitive impairment through radiomics.

Method

Retrospective selection of 90 patients with HIV infection, including 36 asymptomatic neurocognitive impairment (ANI) patients and 54 pre-clinical ANI patients in Beijing YouAn Hospital. All patients received comprehensive neuropsychological assessment and MRI scanning. 3D Slicer software was used to acquire volume of interest (VOI) and radiomics features. Clinical variables and volume of putamen were compared between patients with ANI and pre-clinical ANI. The Kruskal Wallis test was used to analysis multiple comparisons between groups. The relationship between cognitive scores and VOI was compared using linear regression. For radiomics, principal component analysis (PCA) was used to reduce model overfitting and calculations and then a support vector machine (SVM) was used to build a binary classification model. For model performance evaluation, we used an accuracy, sensitivity, specificity and receiver operating characteristic curve (ROC).

Result

There were no significant differences in clinical variables between ANI group and pre-clinical-ANI group (P>0.05). The volume of bilateral putamen was significantly different between AHI group and pre-clinical group (P<0.05), but there was only a trend in the left putamen between ANI-treatment group and pre-clinical treatment group(P = 0.063). Reduced cognitive scores in Verbal Fluency, Attention/Working Memory, Executive Functioning, memory and Speed of Information Processing were negatively correlated with the increased VOI (P<0.05), but the correlation was relatively low. In diagnosing the ANI from pre-clinical ANI, the mean area under the ROC curves (AUC) were 0.85 ± 0.22, the mean sensitivity and specificity were 63.12 ± 5.51 and 94.25% ± 3.08%.

Conclusion

The volumes of putamen in patients with ANI may be larger than patients with pre-clinical ANI, the change of the volume of the putamen may have a certain process; there is a relationship between putamen and cognitive impairment, but the exact mechanism is unclear. Radiomics may be a useful tool for predicting early stage HAND in patients with HIV.

The Increase of HIV-1 Infection, Neurocognitive Impairment, and Type 2 Diabetes in The Rio Grande Valley

The Human Immunodeficiency Virus (HIV-1) infection remains a persistent predicament for the State of Texas, ranking seventh among the most documented HIV cases in the United States. In this regard, the Rio Grande Valley (RGV) in South Texas is considered as one of the least investigated areas of the state with respect to HIV infection and HIV associated comorbidities. Considering the 115% increase in average HIV incidence rates per 100,000 within the RGV from 2007-2015, it is worth characterizing this population with respect to their HIV-1 infection, HIV-1 Associated Neurocognitive Disorders (HAND), and the association of treatment with combined antiretroviral therapy (cART). Moreover, the increased rate of Type-2 Diabetes (T2D) in the RGV population is intertwined with that of HIV-1 infection facing challenges due to the lack of knowledge about prevention to inadequate access to healthcare. Hence, the role of T2D in the development of HAND among the people living with HIV (PLWH) in the RGV will be reviewed to establish a closer link between T2D and HAND in cART-treated patients of the RGV.

Brain tissue transcriptomic analysis of SIV-infected macaques identifies several altered metabolic pathways linked to neuropathogenesis and poly (ADP-ribose) polymerases (PARPs) as potential therapeutic targets

Despite improvements in antiretroviral therapy, human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) remain prevalent in subjects undergoing therapy. HAND significantly affects individuals' quality of life, as well as adherence to therapy, and, despite the increasing understanding of neuropathogenesis, no definitive diagnostic or prognostic marker has been identified. We investigated transcriptomic profiles in frontal cortex tissues of Simian immunodeficiency virus (SIV)-infected Rhesus macaques sacrificed at different stages of infection. Gene expression was compared among SIV-infected animals (n = 11), with or without CD8+ lymphocyte depletion, based on detectable (n = 6) or non-detectable (n = 5) presence of the virus in frontal cortex tissues. Significant enrichment in activation of monocyte and macrophage cellular pathways was found in animals with detectable brain infection, independently from CD8+ lymphocyte depletion. In addition, transcripts of four poly (ADP-ribose) polymerases (PARPs) were up-regulated in the frontal cortex, which was confirmed by real-time polymerase chain reaction. Our results shed light on involvement of PARPs in SIV infection of the brain and their role in SIV-associated neurodegenerative processes. Inhibition of PARPs may provide an effective novel therapeutic target for HIV-related neuropathology.

Alzheimer's disease-like perturbations in HIV-mediated neuronal dysfunctions: understanding mechanisms and developing therapeutic strategies

Excessive exposure to toxic substances or chemicals in the environment and various pathogens, including viruses and bacteria, is associated with the onset of numerous brain abnormalities. Among them, pathogens, specifically viruses, elicit persistent inflammation that plays a major role in Alzheimer's disease (AD) as well as dementia. AD is the most common brain disorder that affects thought, speech, memory and ability to execute daily routines. It is also manifested by progressive synaptic impairment and neurodegeneration, which eventually leads to dementia following the accumulation of Aβ and hyperphosphorylated Tau. Numerous factors contribute to the pathogenesis of AD, including neuroinflammation associated with pathogens, and specifically viruses. The human immunodeficiency virus (HIV) is often linked with HIV-associated neurocognitive disorders (HAND) following permeation through the blood-brain barrier (BBB) and induction of persistent neuroinflammation. Further, HIV infections also exhibited the ability to modulate numerous AD-associated factors such as BBB regulators, members of stress-related pathways as well as the amyloid and Tau pathways that lead to the formation of amyloid plaques or neurofibrillary tangles accumulation. Studies regarding the role of HIV in HAND and AD are still in infancy, and potential link or mechanism between both is not yet established. Thus, in the present article, we attempt to discuss various molecular mechanisms that contribute to the basic understanding of the role of HIV-associated neuroinflammation in AD and HAND. Further, using numerous growth factors and drugs, we also present possible therapeutic strategies to curb the neuroinflammatory changes and its associated sequels.

Prevalence and Predictors of Neurocognitive Impairment in Ethiopian Population Living with HIV

BACKGROUND

Modern antiretroviral therapy has extended the life expectancies of people living with HIV; however, the prevention and treatment of their associated neurocognitive decline have remained a challenge. Consequently, it is desirable to investigate the prevalence and predictors of neurocognitive impairment to help in targeted screening and disease prevention.

MATERIALS AND METHODS

Two hundred and forty-four people living with HIV were interviewed in a study using a cross-sectional design and the International HIV Dementia Scale (IHDS). Additionally, the sociodemographic, clinical, and psychosocial characteristics of the patients were recorded. Chi-square and binary logistic regression analysis were used to determine the level of significance among the independent risk factors and probable neurocognitive impairment.

RESULTS

The point prevalence of neurocognitive impairment was found to be 39.3%. Participants' characteristics of being older than 40 years (AOR= 2.81 (95% CI; 1.11-7.15)), having a history of recreational drug use (AOR= 13.67 (95% CI; 6.42-29.13)), and being non-compliant with prescribed medications (AOR= 2.99 (95% CI; 1.01-8.87)) were independent risk factors for neurocognitive impairment.

CONCLUSION

The identification of predictors, in the Ethiopian people living with HIV, may help in the targeted screening of vulnerable groups during cART follow-up visits. This may greatly help in strategizing and implementation of the prevention program, more so, because (i) HIV-associated neurocognitive impairment is an asymptomatic condition for considerable durations, and (ii) clinical trials on neurocognitive impairment therapies have been unsuccessful.

Opioid and neuroHIV Comorbidity - Current and Future Perspectives

With the current national opioid crisis, it is critical to examine the mechanisms underlying pathophysiologic interactions between human immunodeficiency virus (HIV) and opioids in the central nervous system (CNS). Recent advances in experimental models, methodology, and our understanding of disease processes at the molecular and cellular levels reveal opioid-HIV interactions with increasing clarity. However, despite the substantial new insight, the unique impact of opioids on the severity, progression, and prognosis of neuroHIV and HIV-associated neurocognitive disorders (HAND) are not fully understood. In this review, we explore, in detail, what is currently known about mechanisms underlying opioid interactions with HIV, with emphasis on individual HIV-1-expressed gene products at the molecular, cellular and systems levels. Furthermore, we review preclinical and clinical studies with a focus on key considerations when addressing questions of whether opioid-HIV interactive pathogenesis results in unique structural or functional deficits not seen with either disease alone. These considerations include, understanding the combined consequences of HIV-1 genetic variants, host variants, and μ-opioid receptor (MOR) and HIV chemokine co-receptor interactions on the comorbidity. Lastly, we present topics that need to be considered in the future to better understand the unique contributions of opioids to the pathophysiology of neuroHIV.

Graphical Abstract

Novel elvitegravir nanoformulation for drug delivery across the blood-brain barrier to achieve HIV-1 suppression in the CNS macrophages

The use of antiretroviral therapy (ART) has remarkably decreased the morbidity associated with HIV-1 infection, however, the prevalence of HIV-1-associated neurocognitive disorders (HAND) is still increasing. The blood-brain barrier (BBB) is the major impediment for penetration of antiretroviral drugs, causing therapeutics to reach only suboptimal level to the brain. Conventional antiretroviral drug regimens are not sufficient to improve the treatment outcomes of HAND. In our recent report, we have developed a poloxamer-PLGA nanoformulation loaded with elvitegravir (EVG), a commonly used antiretroviral drug. The nanoformulated EVG is capable of elevating intracellular drug uptake and simultaneously enhance viral suppression in HIV-1-infected macrophages. In this work, we identified the clinical parameters including stability, biocompatibility, protein corona, cellular internalization pathway of EVG nanoformulation for its potential clinical translation. We further assessed the ability of this EVG nanoformulation to cross the in vitro BBB model and suppress the HIV-1 in macrophage cells. Compared with EVG native drug, our EVG nanoformulation demonstrated an improved BBB model penetration cross the in vitro BBB model and an enhanced HIV-1 suppression in HIV-1-infected human monocyte-derived macrophages after crossing the BBB model without altering the BBB model integrity. Overall, this is an innovative and optimized treatment strategy that has a potential for therapeutic interventions in reducing HAND.

Cognitive and Motor Impairment Severity Related to Signs of Subclinical Wernicke's Encephalopathy in HIV Infection

BACKGROUND

Wernicke's encephalopathy (WE) is a neurological condition resulting from thiamine deficiency. Although commonly associated with alcoholism, nonalcoholic WE has been described in individuals with HIV infection, but subclinical WE may be underdiagnosed. The current study questioned whether the presence of subclinical WE signs underlies cognitive and motor deficits in HIV individuals as observed in alcoholism.

SETTING

Fifty-six HIV-positive individuals (HIV+) and 53 HIV-negative controls (HIV-) were assessed on 6 cognitive and motor domains: attention/working memory, production, immediate and delayed episodic memory, visuospatial abilities, and upper-limb motor function.

METHODS

Based on a rating scheme by Caine et al, HIV+ individuals were categorized by subclinical WE risk factors (dietary deficiency, oculomotor abnormality, cerebellar dysfunction, and altered mental state). Performance was expressed as age- and education-corrected Z-scores standardized on controls.

RESULTS

Sorting by Caine criteria yielded 20 HIV+ as Caine 0 (ie, meeting no criteria), 22 as Caine 1 (ie, meeting one criterion), and 14 as Caine 2 (ie, meeting 2 criteria). Comparison among HIV+ Caine subgroups revealed a graded effect: Caine 0 performed at control levels, Caine 1 showed mild to moderate deficits on some domains, and Caine 2 showed the most severe deficits on each domain.

CONCLUSION

This graded severity pattern of performance among Caine subgroups suggests that signs of subclinical WE can partly explain the heterogeneity in HIV-related cognitive and motor impairment. This study highlights the utility of Caine criteria in identifying potential causes of HIV-related neurocognitive disorders and has implications for disease management.

Selective peroxisome proliferator-activated receptor-gamma modulator, INT131 exhibits anti-inflammatory effects in an EcoHIV mouse model

Despite the use of antiretroviral therapy for the treatment of HIV-1 infection, cognitive impairments, that is, HIV-1-associated neurocognitive disorders remain prevalent potentially due to persistent viral replication, production of viral proteins, associated brain inflammation or in certain instances, antiretroviral neurotoxicity. Cellular targets in the brain include microglia which in response to infection release inflammatory markers and viral proteins. Evidence suggests that PPARγ agonists exert anti-inflammatory properties in neurological disorders. However, these agonists namely, thiazolidinediones have limited use in the clinic due to reported adverse side effects. INT131 is a novel non-thiazolidinedione compound that belongs to a new class of drugs known as selective PPARγ modulators. INT131 is considered to have a safer profile; however, its neuroprotective role in vivo is not known.The goal of this study was to examine the effect of INT131 in the context of EcoHIV-induced inflammation in vitro, in primary cultures of mouse glial cells and in vivo, in a mouse model of EcoHIV-associated brain inflammation, as well as characterize its pharmacokinetic properties and brain penetration. In primary cultures of glial cells and in the in vivo mouse model, EcoHIV exposure resulted in a significant elevation of inflammatory markers such as TNFα, IL-1β, CCL3, and C3 which were attenuated with INT131 treatment. Pharmacokinetic analyses revealed that INT131 penetrates into the brain with a brain to blood partition ratio Kp value of 8.5%. Overall, this is the first report to demonstrate that INT131 could be a potential candidate for the treatment of HIV-1-associated brain inflammation.

New Challenges of HIV-1 Infection: How HIV-1 Attacks and Resides in the Central Nervous System

Acquired immunodeficiency syndrome (AIDS) has become one of the most devastating pandemics in recorded history. The main causal agent of AIDS is the human immunodeficiency virus (HIV), which infects various cell types of the immune system that express the CD4 receptor on their surfaces. Today, combined antiretroviral therapy (cART) is the standard treatment for all people with HIV; although it has improved the quality of life of people living with HIV (PLWH), it cannot eliminate the latent reservoir of the virus. Therefore HIV/AIDS has turned from a fatal disease to a chronic disease requiring lifelong treatment. Despite significant viral load suppression, it has been observed that at least half of patients under cART present HIV-associated neurocognitive disorders (HAND), which have been related to HIV-1 infection and replication in the central nervous system (CNS). Several studies have focused on elucidating the mechanism by which HIV-1 can invade the CNS and how it can generate the effects seen in HAND. This review summarizes the research on HIV-1 and its interaction with the CNS with an emphasis on the generation of HAND, how the virus enters the CNS, the relationship between HIV-1 and cells of the CNS, and the effect of cART on these cells.

HIV-1 Tat-Induced Astrocytic Extracellular Vesicle miR-7 Impairs Synaptic Architecture

Although combination antiretroviral therapy (cART) has improved the health of millions of those living with HIV-1 (Human Immunodeficiency Virus, Type 1), the penetration into the central nervous system (CNS) of many such therapies is limited, thereby resulting in residual neurocognitive impairment commonly referred to as NeuroHIV. Additionally, while cART has successfully suppressed peripheral viremia, cytotoxicity associated with the presence of viral Transactivator of transcription (Tat) protein in tissues such as the brain, remains a significant concern. Our previous study has demonstrated that both HIV-1 Tat as well as opiates such as morphine, can directly induce synaptic alterations via independent pathways. Herein, we demonstrate that exposure of astrocytes to HIV-1 protein Tat mediates the induction and release of extracellular vesicle (EV) microRNA-7 (miR-7) that is taken up by neurons, leading in turn, to downregulation of neuronal neuroligin 2 (NLGN2) and ultimately to synaptic alterations. More importantly, we report that these impairments could be reversed by pretreatment of neurons with a neurotrophic factor platelet-derived growth factor-CC (PDGF-CC).

Peroxisome Proliferator-Activated Receptor-gamma agonists exhibit anti-inflammatory and antiviral effects in an EcoHIV mouse model

The widespread use of combination antiretroviral therapy (cART) has resulted in significantly reduced deaths from HIV-1 associated complications and opportunistic infections. However, it is estimated that up to 50% of HIV-1 infected individuals still develop HIV-1 associated neurocognitive disorders (HAND). With no treatment currently available for patients, there is a critical need to identify therapeutic approaches that can treat this disorder. Evidence suggests that targeting Peroxisome Proliferator-Activated Receptor-gamma (PPARγ) can be anti-inflammatory in neurological disorders. Here we show that treatment with PPARγ agonists (rosiglitazone or pioglitazone) in primary cultures of mouse glial cells reversed EcoHIV-induced inflammatory genes (TNFα, IL-1β, CCL2, CCL3, CXCL10) and indicator of oxidative stress (iNOS). Furthermore, in vivo, mice administered with EcoHIV through intracranial injection resulted in upregulation of inflammatory genes (TNFα, IL-1β, IFNγ, CCL2, CCL3, CXCL10) and oxidative stress marker (iNOS) in the brain which was reversed through intraperitoneal administration of PPARγ agonists (rosiglitazone or pioglitazone). Finally, we demonstrated that treatment with these compounds in vivo reduced EcoHIV p24 protein burden in the brain. Our results suggest that treatment with PPARγ agonists are anti-inflammatory and antiviral in an in vivo model of EcoHIV infection. These drugs hold promise as potential candidates for HAND treatment in the future.

Sex Influences SAMHD1 Activity and Susceptibility to Human Immunodeficiency Virus-1 in Primary Human Macrophages

BACKGROUND

Macrophages are major targets for HIV-1, contribute to viral propagation in vivo, and are instrumental in the pathogenesis of HAND. While it is known that host sex affects HIV-1 viremia and influences the severity of HIV-1-associated neurocognitive disease, a cellular or molecular basis for these findings remains elusive.

METHODS

We explored whether sex affects HIV-1 infectivity of primary human macrophages and CD4+ T cells in vitro.

RESULTS

Macrophages derived from female donors were less susceptible to HIV-1 infection than those derived from males. This sex-dependent difference in macrophage infectivity was independent of the requirement for CD4/CCR5-mediated virus entry and was not observed in CD4+ T cells. Investigations into the mechanism governing these sex-dependent differences revealed that the host restriction factor SAMHD1 exists in a hyperphosphorylated, less active state in male-derived macrophages. In addition, the major kinase responsible for SAMHD1 phosphorylation, CDK1, exhibited lower levels of expression in female-derived macrophages in all tested donor pairs. The sex-dependent differences in viral restriction imposed by SAMHD1 were abrogated upon its depletion.

CONCLUSIONS

We conclude that SAMHD1 is an essential modulator of infectivity in a sex-dependent manner in macrophages, constituting a novel component of sex differences in innate immune control of HIV-1.

A central role for glial CCR5 in directing the neuropathological interactions of HIV-1 Tat and opiates

BACKGROUND

The collective cognitive and motor deficits known as HIV-associated neurocognitive disorders (HAND) remain high even among HIV+ individuals whose antiretroviral therapy is optimized. HAND is worsened in the context of opiate abuse. The mechanism of exacerbation remains unclear but likely involves chronic immune activation of glial cells resulting from persistent, low-level exposure to the virus and viral proteins. We tested whether signaling through C-C chemokine receptor type 5 (CCR5) contributes to neurotoxic interactions between HIV-1 transactivator of transcription (Tat) and opiates and explored potential mechanisms.

METHODS

Neuronal survival was tracked in neuronal and glial co-cultures over 72 h of treatment with HIV-1 Tat ± morphine using cells from CCR5-deficient and wild-type mice exposed to the CCR5 antagonist maraviroc or exogenously-added BDNF (analyzed by repeated measures ANOVA). Intracellular calcium changes in response to Tat ± morphine ± maraviroc were assessed by ratiometric Fura-2 imaging (analyzed by repeated measures ANOVA). Release of brain-derived neurotrophic factor (BDNF) and its precursor proBDNF from CCR5-deficient and wild-type glia was measured by ELISA (analyzed by two-way ANOVA). Levels of CCR5 and μ-opioid receptor (MOR) were measured by immunoblotting (analyzed by Student's t test).

RESULTS

HIV-1 Tat induces neurotoxicity, which is greatly exacerbated by morphine in wild-type cultures expressing CCR5. Loss of CCR5 from glia (but not neurons) eliminated neurotoxicity due to Tat and morphine interactions. Unexpectedly, when CCR5 was lost from glia, morphine appeared to entirely protect neurons from Tat-induced toxicity. Maraviroc pre-treatment similarly eliminated neurotoxicity and attenuated neuronal increases in [Ca²⁺]_i caused by Tat ± morphine. proBDNF/BDNF ratios were increased in conditioned media from Tat ± morphine-treated wild-type glia compared to CCR5-deficient glia. Exogenous BDNF treatments mimicked the pro-survival effect of glial CCR5 deficiency against Tat ± morphine.

CONCLUSIONS

Our results suggest a critical role for glial CCR5 in mediating neurotoxic effects of HIV-1 Tat and morphine interactions on neurons. A shift in the proBDNF/BDNF ratio that favors neurotrophic support may occur when glial CCR5 signaling is blocked. Some neuroprotection occurred only in the presence of morphine, suggesting that loss of CCR5 may fundamentally change signaling through the MOR in glia.

HIV Neuroinfection and Alzheimer's Disease: Similarities and Potential Links?

Environmental factors such as chemicals, stress and pathogens are now widely believed to play important roles in the onset of some brain diseases, as they are associated with neuronal impairment and acute or chronic inflammation. Alzheimer’s disease (AD) is characterized by progressive synaptic dysfunction and neurodegeneration that ultimately lead to dementia. Neuroinflammation also plays a prominent role in AD and possible links to viruses have been proposed. In particular, the human immunodeficiency virus (HIV) can pass the blood-brain barrier and cause neuronal dysfunction leading to cognitive dysfunctions called HIV-associated neurocognitive disorders (HAND). Similarities between HAND and HIV exist as numerous factors involved in AD such as members of the amyloid and Tau pathways, as well as stress-related pathways or blood brain barrier (BBB) regulators, seem to be modulated by HIV brain infection, leading to the accumulation of amyloid plaques or neurofibrillary tangles (NFT) in some patients. Here, we summarize findings regarding how HIV and some of its proteins such as Tat and gp120 modulate signaling and cellular pathways also impaired in AD, suggesting similarities and convergences of these two pathologies.

Nicotinic Acetylcholine Receptors in HIV: Possible Roles During HAND and Inflammation

Infection with the human immunodeficiency virus (HIV) remains a threat to global health. Since its discovery, many efforts have been directed at understanding the mechanisms and consequences of infection. Although there have been substantial advances since the advent of antiretroviral therapy, there are still complications that significantly compromise the health of infected patients, particularly, chronic inflammation and HIV-associated neurocognitive disorders (HAND). In this review, a new perspective is addressed in the field of HIV, where the alpha7 nicotinic acetylcholine receptor (α7-nAChR) is the protagonist. We comprehensively discuss the available evidence implicating α7-nAChRs in the context of HIV and provide possible explanations about its role in HAND and inflammation in both the central nervous system and the periphery.

Methamphetamine augment HIV-1 Tat mediated memory deficits by altering the expression of synaptic proteins and neurotrophic factors

Methamphetamine (METH) abuse is common among individuals infected with HIV-1 and has been shown to affect HIV replication and pathogenesis. These HIV-1 infected individuals also exhibit greater neuronal injury and higher cognitive decline. HIV-1 proteins, specifically gp120 and HIV-1 Tat, have been earlier shown to affect neurocognition. HIV-1 Tat, a viral protein released early during HIV-1 replication, contributes to HIV-associated neurotoxicity through various mechanisms including production of pro-inflammatory cytokines, reactive oxygen species and dysregulation of neuroplasticity. However, the combined effect of METH and HIV-1 Tat on neurocognition and its potential effect on neuroplasticity mechanisms remains largely unknown. Therefore, the present study was undertaken to investigate the combined effect of METH and HIV-1 Tat on behavior and on the expression of neuroplasticity markers by utilizing Doxycycline (DOX)-inducible HIV-1 Tat (1-86) transgenic mice. Expression of Tat in various brain regions of these mice was confirmed by RT-PCR. The mice were administered with an escalating dose of METH (0.1 mg/kg to 6 mg/kg, i.p) over a 7-day period, followed by 6 mg/kg, i.p METH twice a day for four weeks. After three weeks of METH administration, Y maze and Morris water maze assays were performed to determine the effect of Tat and METH on working and spatial memory, respectively. Compared with controls, working memory was significantly decreased in Tat mice that were administered METH. Moreover, significant deficits in spatial memory were also observed in Tat-Tg mice that were administered METH. A significant reduction in the protein expressions of synapsin 1, synaptophysin, Arg3.1, PSD-95, and BDNF in different brain regions were also observed. Expression levels of Calmodulin kinase II (CaMKII), a marker of synaptodendritic integrity, were also significantly decreased in HIV-1 Tat mice that were treated with METH. Together, this data suggests that METH enhances HIV-1 Tat-induced memory deficits by reducing the expression of pre- and postsynaptic proteins and neuroplasticity markers, thus providing novel insights into the molecular mechanisms behind neurocognitive impairments in HIV-infected amphetamine users.

T cells establish and maintain CNS viral infection in HIV-infected humanized mice

The human brain is an important site of HIV replication and persistence during antiretroviral therapy (ART). Direct evaluation of HIV infection in the brains of otherwise healthy individuals is not feasible; therefore, we performed a large-scale study of bone marrow/liver/thymus (BLT) humanized mice as an in vivo model to study HIV infection in the brain. Human immune cells, including CD4+ T cells and macrophages, were present throughout the BLT mouse brain. HIV DNA, HIV RNA, and/or p24+ cells were observed in the brains of HIV-infected animals, regardless of the HIV isolate used. HIV infection resulted in decreased numbers of CD4+ T cells, increased numbers of CD8+ T cells, and a decreased CD4+/CD8+ T cell ratio in the brain. Using humanized T cell-only mice (ToM), we demonstrated that T cells establish and maintain HIV infection of the brain in the complete absence of human myeloid cells. HIV infection of ToM resulted in CD4+ T cell depletion and a reduced CD4+/CD8+ T cell ratio. ART significantly reduced HIV levels in the BLT mouse brain, and the immune cell populations present were indistinguishable from those of uninfected controls, which demonstrated the effectiveness of ART in controlling HIV replication in the CNS and returning cellular homeostasis to a pre-HIV state.

Is the History of Substance Abuse Correlated with Neuropsychiatric Disorders and Co-morbid HIV Infection? An Urban Population Study

BACKGROUND

Human immunodeficiency virus (HIV) infection remains a serious immunological disease with new infections in the U.S. disproportionately reported in minority populations. For many years, the District of Columbia (DC) has reported the highest HIV infection rate in the nation. Drug abuse and addiction is also prevalent in DC and has traditionally been linked to HIV/AIDS because of the likelihood for opportunistic infections. Despite this data, the relationship between HIV status, drugs of abuse, and the incidence of neurological disorders are scarcely reported for minority populations.

METHOD

We carried out a retrospective study on the prevalence of substance abuse in HIV and their association with neuropsychiatric comorbidities in an African American subpopulation in Washington DC.

FINDINGS

Our data suggests an 86 percent prevalence of drug use in the HIV patients with neuropsychiatric comorbidities, with cocaine use being significantly higher in patients with major depressive disorder (MDD) and bipolar disorder (BD), whereas PCP use was associated with patients with schizophrenia. The mean CD4 count was elevated in patients with neuropsychiatric disease, and specifically in MDD patients. CD8 counts were elevated as expected for HIV status but were not influenced by disease diagnosis. A majority (2/3) of patients were on HAART therapy, however the records did not account for adherence.

CONCLUSION

These data suggest that neuropsychiatric comorbidities are independent of HIV disease progression but are correlated with certain illicit drugs of abuse.

Prevalence of MMP-8 gene polymorphisms in HIV-infected individuals and its association with HIV-associated neurocognitive disorder

Matrix metalloproteinases (MMPs) are well-known as mediators of neuroinflammation in HIV-associated neurocognitive disorder (HAND). Increased levels of MMP-8 have been observed in the HIV-infected patients. Thus, the aim of this study was to evaluate the association of MMP-8 gene polymorphisms with modulation of HAND severity and its prevalence in HIV-infected and healthy individuals. We enrolled a total of 150 HIV-infected individuals, 50 HAND patients, 100 HIV-infected and 150 healthy individuals. MMP-8 (-799C/T, +17C/G) polymorphisms were genotyped by PCR-RFLP. MMP-8 -799TT genotype and +17G allele showed the higher risk for modulation of HAND severity (OR=2.20, P=0.19; OR=1.97, P=0.23). MMP-8 -799TT genotype differed significantly in HIV-infected individuals compared to healthy controls (20.0% vs. 11.3%, OR=2.36, P=0.048). Haplotype TG increased the risk for modulation of HAND severity (OR=2.29, P=0.29). MMP-8 -799TT and +17CG genotypes were overrepresented in the intermediate HIV disease stage compared with healthy controls (25.9% vs. 11.3%, OR=4.34, P=0.021, 14.8% vs. 9.3%, OR=2.88, P=0.11). MMP-8 +17CG genotype enhanced the risk for modulation of HAND severity in tobacco using HAND patients (OR=5.01, P=0.17). MMP-8 -799TT genotype was more frequent in tobacco using HIV-infected individuals compared with nonusers (26.3% vs. 16.7%, OR=2.08, P=0.32). MMP-8 +17CG genotype increased the risk for modulation of HAND severity in alcohol using HAND patients (OR=4.99, P=0.18). In conclusion, MMP-8 polymorphisms independently and with alcohol and tobacco usage revealed a trend of higher risk for the modulation of HAND severity. MMP-8 -799TT genotype was associated with the advancement of HIV disease.

Exosomal miR-9 Released from HIV Tat Stimulated Astrocytes Mediates Microglial Migration

Chronic neuroinflammation still remains a common underlying feature of HIV-infected patients on combined anti-retroviral therapy (cART). Previous studies have reported that despite near complete suppression of virus replication by cART, cytotoxic viral proteins such as HIV trans-activating regulatory protein (Tat) continue to persist in tissues such as the brain and the lymph nodes, thereby contributing, in part, to chronic glial activation observed in HIV-associated neurological disorders (HAND). Understanding how the glial cells cross talk to mediate neuropathology is thus of paramount importance. MicroRNAs (miR) also known as regulators of gene expression, have emerged as key paracrine signaling mediators that regulate disease pathogenesis and cellular crosstalk, through their transfer via the extracellular vesicles (EV). In the current study we have identified a novel function of miR-9, that of mediating microglial migration. We demonstrate that miR-9 released from Tat-stimulated astrocytes can be taken up by microglia resulting in their migratory phenotype. Exposure of human astrocytoma (A172) cells to HIV Tat resulted in induction and release of miR-9 in the EVs, which, was taken up by microglia, leading in turn, increased migration of the latter cells, a process that could be blocked by both an exosome inhibitor GW4869 or a specific target protector of miR-9. Furthermore, it was also demonstrated that EV miR-9 mediated inhibition of the expression of target PTEN, via its binding to the 3'UTR seed sequence of the PTEN mRNA, was critical for microglial migration. To validate the role of miR-9 in this process, microglial cells were treated with EVs loaded with miR-9, which resulted in significant downregulation of PTEN expression with a concomitant increase in microglial migration. These findings were corroborated by transfecting microglia with a specific target protector of PTEN, that blocked miR-9-mediated downregulation of PTEN as well as microglial migration. In vivo studies wherein the miR-9 precursor-transduced microglia were transplanted into the striatum of mice, followed by assessing their migration in response to a stimulus administered distally, further validated the role of miR-9 in mediating microglial migration. Collectively, our findings provide evidence that glial crosstalk via miRs released from EVs play a vital role in mediating disease pathogenesis and could provide new avenues for development of novel therapeutic strategies aimed at dampening neuropathogenesis.

Systematic review of the prevalence of psychiatric illness and sleep disturbance as co-morbidities of HIV infection in the UK

Psychiatric illness and sleeping disorders are important co-morbidities of human immunodeficiency virus (HIV) infection, which impact both the individual and antiretroviral therapy (ART) selection. This systematic review aimed to assess the prevalence of psychiatric illness and sleep disturbance in people living with HIV (PLHIV) in the UK. Systematic searches for publications reporting epidemiological data for psychiatric co-morbidities and sleep disturbance with HIV were conducted in Embase, MEDLINE, Cochrane Library, eight key conferences (2013-2015), and by hand-searching references of included publications. Data were extracted from publications (2000 onwards) reporting the UK prevalence of depression, anxiety, suicide ideation, or sleep disturbance as a co-morbidity of HIV infection. Comparative UK general population data were obtained from the 2007 Adult Psychiatric Morbidity in England household survey, the 2012 Health Survey for England, and 'PatientBase' (epidemiological database). Sixteen publications met the inclusion criteria. Amongst PLHIV in the UK, the prevalence of depression varied from 17-47%, compared with a reported 2-5% prevalence for the UK general population. A similar disparity was observed in the prevalence of anxiety (22-49% PLHIV versus 4-5% general population), depression or anxiety (50-58% PLHIV versus 27% general population), difficulty sleeping (61% PLHIV versus 10% population), and suicide ideation (31% PLHIV versus 1% general population). This systematic review of UK data demonstrates that rates of psychiatric illness and sleep disturbance are substantially higher amongst PLHIV than in the general population. These data underline the importance of fully considering sleep and psychiatric issues prior to selection and prescription of antiretroviral drugs, as well as the need for ongoing psychiatric and psychological support for PLHIV on ART.

A Review of the Literature Regarding Sleep and Cardiometabolic Disease in African Descent Populations

In the twenty-first century, African descent populations on both the continent of Africa and throughout the world are experiencing a high rate of both sleep disturbances and cardiometabolic diseases. The most common sleep disturbances are reduced sleep duration, insomnia, disordered circadian rhythm, and obstructive sleep apnea. Cardiometabolic diseases include hypertension, coronary artery disease, diabetes, hyperlipidemia, and the metabolic syndrome. This review seeks to call attention to new insights regarding the impact of sleep disturbance on cardiometabolic risk factors and outcomes and then apply these concepts to African descent populations, a relatively understudied population. Initial data suggest disparities in sleep quality may have an important role in current and emerging patterns of cardiometabolic disease for African descent populations both in the United States and abroad.

CLINICALTRIALSGOV IDENTIFIER

Not applicable.

A study of neuropsychological profile of human immunodeficiency virus-positive children and adolescents on antiretroviral therapy

AIMS

The aim is to study the neuropsychological and functional profile of children and adolescents with human immunodeficiency virus (HIV) infection on antiretroviral therapy (ART) and the association between the neuropsychological status and medical illness variables, treatment variables, and functional status in the cases of the sample and compare with normal controls.

MATERIALS AND METHODS

Forty-two HIV-positive children and adolescents on ART were evaluated and compared with 40 matched controls not known to be HIV-positive. The tools used were the Wechsler Intelligence Scale for Children-III R for neuropsychological evaluation, the Brief Impairment Scale to assess functional impairment, and a semi-structured questionnaire to obtain other relevant details.

RESULTS

There were significant differences between the verbal, performance intelligence quotients (IQs), global IQ score, and several individual subtests between cases and controls. The HIV group was also found to have a significant functional impairment.

CONCLUSION

Our findings show that HIV infection is associated with significant cognitive and functional impairment. The role of ART in these impairments requires further study. Such understanding can help to introduce wholesome and relatively safer management strategies for youngsters with HIV infection and improve their quality of life.

HIV, Tat and dopamine transmission

Human Immunodeficiency Virus (HIV) is a progressive infection that targets the immune system, affecting more than 37 million people around the world. While combinatorial antiretroviral therapy (cART) has lowered mortality rates and improved quality of life in infected individuals, the prevalence of HIV associated neurocognitive disorders is increasing and HIV associated cognitive decline remains prevalent. Recent research has suggested that HIV accessory proteins may be involved in this decline, and several studies have indicated that the HIV protein transactivator of transcription (Tat) can disrupt normal neuronal and glial function. Specifically, data indicate that Tat may directly impact dopaminergic neurotransmission, by modulating the function of the dopamine transporter and specifically damaging dopamine-rich regions of the CNS. HIV infection of the CNS has long been associated with dopaminergic dysfunction, but the mechanisms remain undefined. The specific effect(s) of Tat on dopaminergic neurotransmission may be, at least partially, a mechanism by which HIV infection directly or indirectly induces dopaminergic dysfunction. Therefore, precisely defining the specific effects of Tat on the dopaminergic system will help to elucidate the mechanisms by which HIV infection of the CNS induces neuropsychiatric, neurocognitive and neurological disorders that involve dopaminergic neurotransmission. Further, this will provide a discussion of the experiments needed to further these investigations, and may help to identify or develop new therapeutic approaches for the prevention or treatment of these disorders in HIV-infected individuals.

HIV-associated synaptic degeneration

Human immunodeficiency virus (HIV) infection induces neuronal injuries, with almost 50% of infected individuals developing HIV-associated neurocognitive disorders (HAND). Although highly activate antiretroviral therapy (HAART) has significantly reduced the incidence of severe dementia, the overall prevalence of HAND remains high. Synaptic degeneration is emerging as one of the most relevant neuropathologies associate with HAND. Previous studies have reported critical roles of viral proteins and inflammatory responses in this pathogenesis. Infected cells, including macrophages, microglia and astrocytes, may release viral proteins and other neurotoxins to stimulate neurons and cause excessive calcium influx, overproduction of free radicals and disruption of neurotransmitter hemostasis. The dysregulation of neural circuits likely leads to synaptic damage and loss. Identification of the specific mechanism of the synaptic degeneration may facilitate the development of effective therapeutic approaches to treat HAND.

Interplay between Autophagy, Exosomes and HIV-1 Associated Neurological Disorders: New Insights for Diagnosis and Therapeutic Applications

The autophagy–lysosomal pathway mediates a degradative process critical in the maintenance of cellular homeostasis as well as the preservation of proper organelle function by selective removal of damaged proteins and organelles. In some situations, cells remove unwanted or damaged proteins and RNAs through the release to the extracellular environment of exosomes. Since exosomes can be transferred from one cell to another, secretion of unwanted material to the extracellular environment in exosomes may have an impact, which can be beneficial or detrimental, in neighboring cells. Exosome secretion is under the influence of the autophagic system, and stimulation of autophagy can inhibit exosomal release and vice versa. Neurons are particularly vulnerable to degeneration, especially as the brain ages, and studies indicate that imbalances in genes regulating autophagy are a common feature of many neurodegenerative diseases. Cognitive and motor disease associated with severe dementia and neuronal damage is well-documented in the brains of HIV-infected individuals. Neurodegeneration seen in the brain in HIV-1 infection is associated with dysregulation of neuronal autophagy. In this paradigm, we herein provide an overview on the role of autophagy in HIV-associated neurodegenerative disease, focusing particularly on the effect of autophagy modulation on exosomal release of HIV particles and how this interplay impacts HIV infection in the brain. Specific autophagy–regulating agents are being considered for therapeutic treatment and prevention of a broad range of human diseases. Various therapeutic strategies for modulating specific stages of autophagy and the current state of drug development for this purpose are also evaluated.

Measuring and managing cognitive impairment in HIV

: Cognitive impairment remains a frequently reported complaint in HIV-positive patients despite virologically suppressive antiretroviral therapy. Rates of cognitive impairment in antiretroviral treated HIV-positive cohorts vary and strongly depend on definitions utilized.The underlying pathogenesis is likely to be multifactorial and includes immune activation, neuroinflammation, antiretroviral neurotoxicity, the presence of noninfectious comorbidities such as vascular disease and depression and patient lifestyle factors such as recreational drug use.Contributing factors to cognitive impairment may change over time with ageing HIV-positive populations. Cerebrovascular disease and neurodegenerative causes of cognitive impairment may become more common with advancing age; how these factors interact with HIV-associated cognitive impairment is not yet known.Cerebrospinal fluid HIV RNA escape may occur in up to 10% of patients undergoing lumbar puncture clinically and can be associated with compartmentalized and resistant virus.Changes in antiretroviral therapy in patients with cognitive impairment should be based on current and historic resistance profiles of cerebrospinal fluid and plasma virus, or on potential antiretroviral drug neurotoxicity. Whether and how antiretroviral therapy should be changed in the absence of these factors is not known and requires study in adequately powered randomized trials in carefully selected clinical cohorts.

A Simplified Approach to Encephalitis and Its Mimics: Key Clinical Decision Points in the Setting of Specific Imaging Abnormalities

RATIONALE AND OBJECTIVES

Infectious encephalitis is a relatively common cause of morbidity and mortality. Treatment of infectious encephalitis with antiviral medication can be highly effective when administered promptly. Clinical mimics of encephalitis arise from a broad range of pathologic processes, including toxic, metabolic, neoplastic, autoimmune, and cardiovascular etiologies. These mimics need to be rapidly differentiated from infectious encephalitis to appropriately manage the correct etiology; however, the many overlapping signs of these various entities present a challenge to accurate diagnosis. A systematic approach that considers both the clinical manifestations and the imaging findings of infectious encephalitis and its mimics can contribute to more accurate and timely diagnosis.

MATERIALS AND METHODS

Following an institutional review board approval, a health insurance portability and accountability act (HIPAA)-compliant search of our institutional imaging database (teaching files) was conducted to generate a list of adult and pediatric patients who presented between January 1, 1995 and October 10, 2013 for imaging to evaluate possible cases of encephalitis. Pertinent medical records, including clinical notes as well as surgical and pathology reports, were reviewed and correlated with imaging findings. Clinical and imaging findings were combined to generate useful flowcharts designed to assist in distinguishing infectious encephalitis from its mimics. Key imaging features were reviewed and were placed in the context of the provided flowcharts.

RESULTS

Four flowcharts were presented based on the primary anatomic site of imaging abnormality: group 1: temporal lobe; group 2: cerebral cortex; group 3: deep gray matter; and group 4: white matter. An approach that combines features on clinical presentation was then detailed. Imaging examples were used to demonstrate similarities and key differences.

CONCLUSIONS

Early recognition of infectious encephalitis is critical, but can be quite complex due to diverse pathologies and overlapping features. Synthesis of both the clinical and imaging features of infectious encephalitis and its mimics is critical to a timely and accurate diagnosis. The use of the flowcharts presented in this article can further enable both clinicians and radiologists to more confidently differentiate encephalitis from its mimics and improve patient care.

Serum levels of adiponectin and leptin in asthmatic patients and its relation with asthma severity, lung function and BMI

INTRODUCTION

Asthma is one of the diseases which has a high prevalence in developed and developing countries. The relationship between asthma and obesity has always been focused by researchers. In this field, adipokines, especially adiponectin and leptin have highly attended by the scientist. The aim of this study was to determine the serum level of adiponectin, leptin and the leptin/adiponectin ratio in asthmatic patients and its relationship with disease severity, lung function and BMI (body mass index).

METHODS

In this cross-sectional study, 90 asthmatic women admitted to the tertiary referral hospital in Kurdistan province - Iran, were examined. First, BMI was measured and then pulmonary function tests were performed in all asthmatics patient. Forced expiratory volume in 1s (FEV1), forced vital capacity (FVC), and FEV1/FVC, were measured. At the end, blood samples were collected and serum level of adiponectin and leptin were measured by ELISA method.

RESULT

Serum leptin and leptin/adiponectin levels correlated positively with asthma severity and BMI (p=0.0001), but there was no correlation between adiponectin level with asthma severity and BMI (p>0.05), also serum leptin and leptin/adiponectin levels inversely correlated with FEV1 and FVC in patient (p=0.0001).

CONCLUSION

Asthma is linked with obesity, and there is an association between asthma severity and BMI with serum leptin and leptin/adiponectin levels, but our results do not support a significant role of adiponectin in obesity or asthma.

HIV-Associated Neurocognitive Disorder (HAND) and the Prospect of Brain-Penetrating Protease Inhibitors for Antiretroviral Treatment

The advent of combined active antiretroviral therapy (cART) dramatically improved HIV management and patient care of HIV-infected individuals. This treatment regimen resulted in a significant reduction of HIV/AIDS-related mortality and greatly improved life expectancies of those patients with access to cART. However, among many HIV-related complications, neurocognitive dysfunction, known as HIV-associated neurocognitive disorder (HAND) has been a major issue. While the cART regimen has been effective in reduction of HAND in many patients, the prevalence of HAND is increasing as HIV/AIDS patients live longer. HIV infection and its subsequent manifestation of HAND is complex. It is evident that the brain can serve as a sanctuary for HIV replication and HAND can remain in patients even with cART treatment due to poor blood-brain barrier permeability of the majority of current antiretroviral agents. Conceivably, cART needs to have improved CNS penetration properties for effective treatment and possible prevention of HAND. Therefore, design and development of new antiretroviral agents that can penetrate into the CNS effectively, could block HIV replication and significantly reduce the viral load in cerebrospinal fluid. This may prevent HAND and related symptoms. HIV protease inhibitors (PIs) are a critical component of cART. Over the years, we have designed and synthesized a range of highly potent and novel PIs including the FDA approved drug, darunavir, which is used as a first-line treatment. In an effort to improve CNS penetration, we have been involved in the design and development of potent PIs with improved in vitro brain penetration properties. Herein we provide a brief review that cover insights and discussion of HAND and our work on PI development to ameliorate HIV-associated neurocognitive disorders.

HIV-1 Tat Primes and Activates Microglial NLRP3 Inflammasome-Mediated Neuroinflammation

Neuroinflammation associated with HIV-1 infection is a problem affecting ∼50% of HIV-infected individuals. NLR family pyrin domain containing 3 (NLRP3) inflammasome has been implicated in HIV-induced microglial activation, but the mechanism(s) remain unclear. Because HIV-1 Transactivator of Transcription (Tat) protein continues to be present despite antiretroviral therapy and activates NF-kB, we hypothesized that Tat could prime the NLRP3 inflammasome. We found a dose- and time-dependent induction of NLRP3 expression in microglia exposed to Tat compared with control. Tat exposure also time-dependently increased the mature caspase-1 and IL-1β levels and enhanced the IL-1β secretion. These in vitro findings were validated in archival brain tissues from Simian Immunodeficiency Virus (SIV)-infected and uninfected rhesus macaques. Further validation of NLRP3 priming in vivo involved administration of lipopolysaccharide (LPS) to HIV transgenic (Tg) rats followed by assessment of IL-1β mRNA expression and inflammasome activation (ASC oligomers and mature IL-1β). Intriguingly, LPS potentiated upregulation of IL-1β mRNA and inflammasome activation in HIV-Tg rats compared with the wild-type controls. Interestingly, we found an inverse relationship in the expression of NLRP3 and its negative regulator, miR-223, suggesting a miR-223-mediated mechanism for Tat-induced NLRP3 priming. Furthermore, blockade of NLRP3 resulted in decreased IL-1β secretion. Collectively, these findings suggest a novel role of Tat in priming and activating the NLRP3 inflammasome. Therefore, NLRP3 can be envisioned as a therapeutic target for ameliorating Tat-mediated neuroinflammation.SIGNIFICANCE STATEMENT Despite successful suppression of viremia with increased longevity in the era of combined antiretroviral therapy, chronic inflammation with underlying neurocognitive impairment continues to afflict almost 50% of infected individuals. Viral, bacterial, and cellular products have all been implicated in promoting the chronic inflammation found in these individuals. Understanding the molecular mechanism(s) by which viral proteins such as HIV-1 Transactivator of Transcription (Tat) protein can activate microglia is thus of paramount importance. Herein, we demonstrate a novel role of Tat in priming and activating NLR family pyrin domain containing 3 (NLRP3) inflammasomes in microglial cells and in HIV-Tg rats administered lipopolysaccharide. Targeting NLRP3 inflammasome pathway mediators could thus be developed as therapeutic interventions to alleviate or prevent neuroinflammation and subsequent cognitive impairment in HIV-positive patients.