A concise panel of biomarkers identifies neurocognitive functioning changes in HIV-infected individuals

Cerebrospinal Fluid and Peripheral Blood Lymphomonocyte Single-Cell Transcriptomics in a Subject with Multiple Sclerosis Acutely Infected with HIV

Signatures of neurodegeneration in clinical samples from a subject with multiple sclerosis (MS) acutely infected with HIV were investigated with single-cell transcriptomics using 10X Chromium technology. Sequencing was carried out on NovaSeq-TM, and the analysis was performed with Cell Ranger software (v 7.1.0) associated with a specifically established bioinformatic pipeline. A total of 1446 single-cell transcriptomes in cerebrospinal fluid (CSF) and 4647 in peripheral blood mononuclear cells (PBMCs) were obtained. In the CSF, many T-cell lymphocytes with an enriched amount of plasma cells and plasmacytoid dendritic (pDC) cells, as compared to the PBMCs, were detected. An unsupervised cluster analysis, putting together our patient transcriptomes with those of a publicly available MS scRNA-seq dataset, showed up-regulated microglial neurodegenerative gene expression in four clusters, two of which included our subject's transcriptomes. A few HIV-1 transcripts were found only in the CD4 central memory T-cells of the CSF compartment, mapping to the gag-pol, vpu, and env regions. Our data, which describe the signs of neurodegenerative gene expression in a very peculiar clinical situation, did not distinguish the cause between multiple sclerosis and HIV infection, but they can give a glimpse of the high degree of resolution that may be obtained by the single-cell transcriptomic approach.

Tryptophan-Kynurenine Pathway Activation and Cognition in Virally Suppressed Women With HIV

BACKGROUND

Immune and cognitive dysfunction persists even in virally suppressed women with HIV (VS-WWH). Since inflammation and HIV proteins induce the enzyme indoleamine 2,3-dioxygenase (IDO), converting tryptophan (T) to kynurenine (K) while producing downstream neurotoxic metabolites, we investigated IDO activation (KT ratio) in relation to cognition in VS-WWH and demographically similar women without HIV (WWoH).

METHODS

Ninety-nine VS-WWH on stable antiretroviral therapy and 102 WWoH (median age 52 vs 54 years; 73% vs 74% Black, respectively) from the New York and Chicago sites of the Women's Interagency HIV Study (WIHS) completed a neuropsychological test battery assessing motor function, processing speed, attention/working memory, verbal fluency, verbal learning and memory, and executive function and had plasma measured for tryptophan-kynurenine metabolites through liquid chromatography-tandem mass spectrometry and monocyte-derived [soluble cluster of differentiation-14 (sCD14), soluble cluster of differentiation-163 (sCD163), monocyte chemoattractant protein-1 (MCP-1)] plus general inflammatory markers [tumor necrosis factor alpha-2 receptor (TNF-R2), high-sensitivity C-reactive protein, high-sensitivity interleukin-6] through enzyme-linked immunosorbent assays between 2017 and 2020.

RESULTS

VS-WWH had a higher KT ratio (P < 0.01) and higher sCD14 levels (P < 0.05) compared with WWoH. Higher sCD163 was associated with higher KT ratio (R = 0.29, P < 0.01) and worse fine motor function in VS-WWH; after adjusting for sCD163 and sCD14 in multivariable regressions, higher KT ratio remained significantly associated with impaired fine motor function in VS-WWH only (standardized β = -0.29, P < 0.05). IDO activation was not associated with cognition in WWoH.

CONCLUSIONS

IDO activation (K:T) was associated with worse fine motor control in VS-WWH independent of measured systemic inflammation. Further studies investigating biological mechanisms linking IDO activation to fine motor function among VS-WWH are warranted.

Multimodal Approach to Neurocognitive Function in People Living with HIV in the cART Era: A Comprehensive Review

Combination antiretroviral treatment (cART) has revolutionized the management of human immunodeficiency virus (HIV) and has markedly improved the disease burden and life expectancy of people living with HIV. HIV enters the central nervous system (CNS) early in the course of infection, establishes latency, and produces a pro-inflammatory milieu that may affect cognitive functions, even in the cART era. Whereas severe forms of neurocognitive impairment (NCI) such as HIV-associated dementia have declined over the last decades, milder forms have become more prevalent, are commonly multifactorial, and are associated with comorbidity burdens, mental health, cART neurotoxicity, and ageing. Since 2007, the Frascati criteria have been used to characterize and classify HIV-associated neurocognitive disorders (HAND) into three stages, namely asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), and HIV-associated dementia (HAD). These criteria are based on a comprehensive neuropsychological assessment that presupposes the availability of validated, demographically adjusted, and normative population data. Novel neuroimaging modalities and biomarkers have been proposed in order to complement NCI assessments, elucidate neuropathogenic mechanisms, and support HIV-associated NCI diagnosis, monitoring, and prognosis. By integrating neuropsychological assessments with biomarkers and neuroimaging into a holistic care approach, clinicians can enhance diagnostic accuracy, prognosis, and patient outcomes. This review interrogates the value of these modes of assessment and proposes a unified approach to NCI diagnosis.

Inflammation and lipid metabolism as potential biomarkers of memory impairment across type 2 diabetes mellitus and severe mental disorders

INTRODUCTION

Neurocognitive impairment is a transdiagnostic feature across several psychiatric and cardiometabolic conditions. The relationship between inflammatory and lipid metabolism biomarkers and memory performance is not fully understood. This study aimed to identify peripheral biomarkers suitable to signal memory decline from a transdiagnostic and longitudinal perspective.

METHODS

Peripheral blood biomarkers of inflammation, oxidative stress and lipid metabolism were assessed twice over a 1-year period in 165 individuals, including 30 with schizophrenia (SZ), 42 with bipolar disorder (BD), 35 with major depressive disorder (MDD), 30 with type 2 diabetes mellitus (T2DM), and 28 healthy controls (HCs). Participants were stratified by memory performance quartiles, taking as a reference their global memory score (GMS) at baseline, into categories of high memory (H; n = 40), medium to high memory (MH; n = 43), medium to low memory (ML; n = 38) and low memory (L; n = 44). Exploratory and confirmatory factorial analysis, mixed one-way analysis of covariance and discriminatory analyses were performed.

RESULTS

L group was significantly associated with higher levels of tumor necrosis factor-alpha (TNF-α) and lower levels of apolipoprotein A1 (Apo-A1) compared to those from the MH and H groups (p < 0.05; η2p = 0.06-0.09), with small to moderate effect sizes. Moreover, the combination of interleukin-6 (IL-6), TNF-α, c-reactive protein (CRP), Apo-A1 and Apo-B compounded the transdiagnostic model that best discriminated between groups with different degrees of memory impairment (χ2 = 11.9-49.3, p < 0.05-0.0001).

CONCLUSIONS

Inflammation and lipid metabolism seem to be associated with memory across T2DM and severe mental illnesses (SMI). A panel of biomarkers may be a useful approach to identify individuals at greater risk of neurocognitive impairment. These findings may have a potential translational utility for early intervention and advance precision medicine in these disorders.

The comorbidity of depression and neurocognitive disorder in persons with HIV infection: call for investigation and treatment

Depression and neurocognitive disorder continue to be the major neuropsychiatric disorders affecting persons with HIV (PWH). The prevalence of major depressive disorder is two to fourfold higher among PWH than the general population (∼6.7%). Prevalence estimates of neurocognitive disorder among PWH range from 25 to over 47% - depending upon the definition used (which is currently evolving), the size of the test battery employed, and the demographic and HIV disease characteristics of the participants included, such as age range and sex distribution. Both major depressive disorder and neurocognitive disorder also result in substantial morbidity and premature mortality. However, though anticipated to be relatively common, the comorbidity of these two disorders in PWH has not been formally studied. This is partly due to the clinical overlap of the neurocognitive symptoms of these two disorders. Both also share neurobehavioral aspects - particularly apathy - as well as an increased risk for non-adherence to antiretroviral therapy. Shared pathophysiological mechanisms potentially explain these intersecting phenotypes, including neuroinflammatory, vascular, and microbiomic, as well as neuroendocrine/neurotransmitter dynamic mechanisms. Treatment of either disorder affects the other with respect to symptom reduction as well as medication toxicity. We present a unified model for the comorbidity based upon deficits in dopaminergic transmission that occur in both major depressive disorder and HIV-associated neurocognitive disorder. Specific treatments for the comorbidity that decrease neuroinflammation and/or restore associated deficits in dopaminergic transmission may be indicated and merit study.

Association of Plasma Eicosanoid Levels With Immune, Viral, and Cognitive Outcomes in People With HIV

BACKGROUND AND OBJECTIVES

To determine whether plasma eicosanoid levels are associated with immune, viral, and cognitive outcomes in people with HIV (PWH).

METHODS

We measured 42 eicosanoids in a longitudinal study of 95 PWH and 25 demographically comparable uninfected participants. Routine clinical chemistry, virologic, immune markers, and a neuropsychological test battery assessing 7 cognitive domains were administered to all participants at 2 study visits over an average of 6.5 months.

RESULTS

Plasma eicosanoid concentrations were elevated in PWH (n = 95) compared with seronegative controls (n = 25) (100% prediction power at 5% false discovery rate [FDR], α = 0.0531) and were negatively associated with lower current and nadir CD4 lymphocyte counts. Higher levels of eicosanoids were associated with impairments in working memory, verbal fluency, and executive function. Higher plasma viral load was associated with elevated proinflammatory eicosanoids (24% prediction power at 5% FDR and 42.4% prediction power at 10% FDR, α = 0.10). Longitudinal analyses showed that eicosanoid levels were correlated with viral load and with plasma creatinine. Despite associations of eicosanoids with viral loads, elevated plasma eicosanoids were similar in virally suppressed and not fully suppressed PWH.

DISCUSSION

These data show that HIV infection is associated with a robust production of eicosanoids that are not substantially reduced by antiretroviral therapy (ART). The sustained elevation of these oxylipins in PWH despite ART may contribute to an accelerated aging phenotype that includes earlier than expected brain and peripheral organ damage.

HIV viral transcription and immune perturbations in the CNS of people with HIV despite ART

People with HIV (PWH) on antiretroviral therapy (ART) experience elevated rates of neurological impairment, despite controlling for demographic factors and comorbidities, suggesting viral or neuroimmune etiologies for these deficits. Here, we apply multimodal and cross-compartmental single-cell analyses of paired cerebrospinal fluid (CSF) and peripheral blood in PWH and uninfected controls. We demonstrate that a subset of central memory CD4+ T cells in the CSF produced HIV-1 RNA, despite apparent systemic viral suppression, and that HIV-1-infected cells were more frequently found in the CSF than in the blood. Using cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq), we show that the cell surface marker CD204 is a reliable marker for rare microglia-like cells in the CSF, which have been implicated in HIV neuropathogenesis, but which we did not find to contain HIV transcripts. Through a feature selection method for supervised deep learning of single-cell transcriptomes, we find that abnormal CD8+ T cell activation, rather than CD4+ T cell abnormalities, predominated in the CSF of PWH compared with controls. Overall, these findings suggest ongoing CNS viral persistence and compartmentalized CNS neuroimmune effects of HIV infection during ART and demonstrate the power of single-cell studies of CSF to better understand the CNS reservoir during HIV infection.

Soluble CD14 is subtype-dependent in serum but not in cerebrospinal fluid in people with HIV

Monocytes and macrophages activation are crucial in human immunodeficiency virus (HIV) central nervous system (CNS) infection and HIV associated neurocognitive disorders (HAND) pathogenesis. The soluble form of CD14 (sCD14) is a marker of monocyte activation. We hypothesized that sCD14 levels would be lower in people with HIV-1 subtype C (HIV-1C) than in HIV-1B owing to a variant Tat cysteine dimotif (C30S31) with reduced chemotactic activity. A total of 68 paired cerebrospinal fluid (CSF) and blood samples from people with HIV (PWH); 27 samples of the HIV-1B subtype and 40 of the non-B HIV-1 subtypes (including 26,HIV-1C), and 18 HIV-negative controls were included. sCD14 levels were quantified using a high-sensitivity enzyme-linked immunosorbent assay. sCD14 increase in serum, but not in CSF, was higher in samples from HIV-1B than HIV-1C (p = 0.002; Cohen's d, 0.7). CSF or serum sCD14 values were not correlated with global deficit score or specific cognitive domains. The impact of HIV-1 on monocyte stimulation biomarkers evaluated by sCD14 in serum was subtype-dependent, higher in HIV-1B than HIV-1C, consistent with reduced chemotactic activity as hypothesized.

Immune Dysregulation Is Associated with Neurodevelopment and Neurocognitive Performance in HIV Pediatric Populations-A Scoping Review

HIV-1 is known for its complex interaction with the dysregulated immune system and is responsible for the development of neurocognitive deficits and neurodevelopmental delays in pediatric HIV populations. Considering that HIV-1-induced immune dysregulation and its association with neurodevelopmental and neurocognitive impairments in pediatric populations are not well understood, we conducted a scoping review on this topic. The study aimed to systematically review the association of blood and cerebrospinal fluid (CSF) immune markers with neurocognitive deficits and neurodevelopmental delays in pediatric HIV populations. PubMed, Scopus, and Web of Science databases were searched using a search protocol designed specifically for this study. Studies were selected based on a set eligibility criterion. Titles, abstracts, and full texts were assessed by two independent reviewers. Data from the selected studies were extracted and analyzed by two independent reviewers. Seven studies were considered eligible for use in this context, which included four cross-sectional and three longitudinal studies. An average of 130 (±70.61) children living with HIV, 138 (±65.37) children exposed to HIV but uninfected and 90 (±86.66) HIV-negative participants were included across the seven studies. Results indicate that blood and CSF immune markers are associated with neurocognitive development/performance in pediatric HIV populations. Only seven studies met the inclusion criteria, therefore, these limited the number of significant conclusions which could have been made by using such an approach. All considered, the evidence suggests that immune dysregulation, as in the case of adult HIV populations, also has a significant association with neurocognitive performance in pediatric HIV populations.

Soluble Biomarkers of Cognition and Depression in Adults with HIV Infection in the Combination Therapy Era

PURPOSE OF REVIEW

Cognitive impairment and depression continue to be common among people with HIV (PWH) in the combination antiretroviral therapy (ART) era. A better understanding of the biological mechanisms that may underpin these disorders is needed. The purpose of this review is to describe published findings on soluble biomarkers from blood and cerebrospinal fluid (CSF) that have been associated with either cognition or depression among PWH in the setting of ART.

RECENT FINDINGS

Several biomarkers, including those that reflect viral persistence, monocyte/macrophage activation, and other processes, are associated with cognition and depressive symptoms. Some but not all results have been consistent across multiple studies. More research has been published on biomarkers of cognition relative to biomarkers of depression (particularly from CSF). More studies are needed that investigate multiple biomarkers to understand the role of distinct but additive pathways in these disorders and to guide the development of new therapies.

Low-Level HIV RNA in Cerebrospinal Fluid and Neurocognitive Performance: A Longitudinal Cohort Study

BACKGROUND

Cognitive complications persist in persons with HIV during suppressive antiretroviral therapy (ART). Low levels of HIV during ART could contribute to these complications. In this study, we measured cerebrospinal fluid (CSF) HIV using a single-copy assay (SCA) to investigate a possible relationship between low-level HIV and cognition.

DESIGN/METHODS

SCA data were analyzed from 3 consecutively paired CSF-plasma specimens collected over a mean of 456 days from 96 participants on suppressive ART. Using mixed models, the presence of CSF HIV by SCA as a risk factor for worse neurocognitive performance was examined.

RESULTS

At baseline on the SCA, 45.8% of participants had detectable plasma HIV RNA (median 8 copies/mL and interquartile range = 3-17 among detectable values) and 17.7% had detectable CSF HIV RNA (median CSF concentration= 3 copies/mL and interquartile range= 2-13 among detectable values). The frequency of CSF HIV RNA detection declined over time in CSF (P = 0.018) with a trend toward decline in plasma (P = 0.064). Detectable CSF HIV RNA during the study was associated with worse performance in the domains of recall (P = 0.014) and motor (P = 0.040) and a trend with worse overall global performance (P = 0.078). Integrase inhibitor use, although very infrequent in this cohort, was associated with better performance in 2 domains.

CONCLUSIONS

Low-level CSF HIV RNA declines with time but is associated with worse cognitive performance in 2 domains. Additional research is needed to better understand the relationship between HIV RNA persistence during long-term ART and central nervous system complications in persons with HIV.

Neurologic Complications of Human Immunodeficiency Virus

PURPOSE OF REVIEW

This article reviews the neurologic complications associated with human immunodeficiency virus (HIV) infection.

RECENT FINDINGS

Neurologic complications of HIV may be caused by direct virally mediated pathology, immune-mediated phenomena in response to viral infection, or opportunistic infections secondary to depletion of lymphocytes. These neurologic disorders may be influenced by the degree of immunosuppression (ie, CD4+ T-cell lymphocyte count) and stage of infection (early versus late), as well as use of antiretroviral therapy, and may manifest as a variety of central and peripheral neurologic syndromes, including the more commonly encountered HIV-associated cognitive disorders and length-dependent sensorimotor polyneuropathy, respectively. Immune dysregulation underlies the majority of these neurologic phenomena, as well as other HIV-associated conditions including immune reconstitution inflammatory syndrome (IRIS), CD8 lymphocytosis, and potentially the development of compartmentalized infection within the CSF, also referred to as CSF escape.

SUMMARY

This article reviews a spectrum of clinical syndromes and related neuropathologic states associated with HIV infection.

Cerebrospinal fluid immune markers and HIV-associated neurocognitive impairments: A systematic review

HIV-1 is responsible for the development of a spectrum of cognitive impairments known as HIV-associated neurocognitive disorder (HAND). In the era of antiretroviral therapy (ART), HAND remains prevalent in people living with HIV (PLWH), despite low or undetectable viral loads. Persistent neuroinflammation likely plays an important role in the contributing biological mechanisms. Multiple cerebrospinal fluid (CSF) immune markers have been studied but it is unclear which markers most consistently correlate with neurocognitive impairment. We therefore conducted a systematic review of studies of the association of CSF immune markers with neurocognitive performance in ART-experienced PLWH. We aimed to synthesize the published data to determine consistent findings and to indicate the most noteworthy CSF markers of HAND. Twenty-nine studies were included, with 20 cross-sectional studies and 9 longitudinal studies. From the group of markers most often assayed, specific monocyte activation (higher levels of Neopterin, sCD163, sCD14) and neuroinflammatory markers (higher levels of IFN-γ, IL-1α, IL-7, IL-8, sTNFR-II and lower levels of IL-6) showed a consistent direction in association with HIV-associated neurocognitive impairment. Furthermore, significant differences exist in CSF immune markers between HIV-positive people with and without neurocognitive impairment, regardless of viral load and nadir/current CD4⁺ count. These markers may be useful in furthering our understanding of the neuropathology, diagnosis and prognosis of HAND. Studies using prospective designs (i.e. pre- and post-interventions), "multi-modal" methods (e.g. imaging, inflammation and neurocognitive evaluations) and utilizing a combination of the markers most commonly associated with HAND may help delineate the mechanisms of HAND.

Compartmentalization of cerebrospinal fluid inflammation across the spectrum of untreated HIV-1 infection, central nervous system injury and viral suppression

OBJECTIVE

To characterize the evolution of central nervous system (CNS) inflammation in HIV-1 infection applying a panel of cerebrospinal fluid (CSF) inflammatory biomarkers to grouped subjects representing a broad spectrum of systemic HIV-1 immune suppression, CNS injury and viral control.

METHODS

This is a cross-sectional analysis of archived CSF and blood samples, assessing concentrations of 10 functionally diverse soluble inflammatory biomarkers by immunoassays in 143 HIV-1-infected subjects divided into 8 groups: untreated primary HIV-1 infection (PHI); four untreated groups defined by their blood CD4+ T lymphocyte counts; untreated patients presenting with subacute HIV-associated dementia (HAD); antiretroviral-treated subjects with ≥1 years of plasma viral suppression; and untreated elite controllers. Twenty HIV-1-uninfected controls were included for comparison. Background biomarkers included blood CD4+ and CD8+ T lymphocytes, CSF and blood HIV-1 RNA, CSF white blood cell (WBC) count, CSF/blood albumin ratio, CSF neurofilament light chain (NfL), and CSF t-tau.

FINDINGS

HIV-1 infection was associated with a broad compartmentalized CSF inflammatory response that developed early in its course and changed with systemic disease progression, development of neurological injury, and viral suppression. CSF inflammation in untreated individuals without overt HAD exhibited at least two overall patterns of inflammation as blood CD4+ T lymphocytes decreased: one that peaked at 200-350 blood CD4+ T cells/μL and associated with lymphocytic CSF inflammation and HIV-1 RNA concentrations; and a second that steadily increased through the full range of CD4+ T cell decline and associated with macrophage responses and increasing CNS injury. Subacute HAD was distinguished by a third inflammatory profile with increased blood-brain barrier permeability and robust combined lymphocytic and macrophage CSF inflammation. Suppression of CSF and blood HIV-1 infections by antiretroviral treatment and elite viral control were associated with reduced CSF inflammation, though not fully to levels found in HIV-1 seronegative controls.

Cognitive and Neuronal Link With Inflammation: A Longitudinal Study in People With and Without HIV Infection

BACKGROUND

Across many settings, lack of virologic control remains common in people with HIV (PWH) because of late presentation and lack of retention in care. This contributes to neuronal damage and neurocognitive impairment, which remains prevalent. More evidence is needed to understand these outcomes in both PWH and people without HIV (PWOH).

METHODS

We recruited PWH initiating antiretroviral therapy and PWOH at 2 sites in the United States. One hundred eight adults were enrolled (56 PWOH and 52 PWH), most of whom had a second assessment at least 24 weeks later (193 total assessments). Tumor necrosis factor alpha, monocyte chemotactic protein-1 (MCP-1), neopterin, soluble CD14, and neurofilament light chain protein (NFL) were measured in plasma and cerebrospinal fluid (CSF). Using multivariate models including Bayesian model averaging, we analyzed factors associated with global neuropsychological performance (NPT-9) and CSF NFL at baseline and over time.

RESULTS

At baseline, higher CSF MCP-1 and plasma sCD14 were associated with worse NPT-9 in PWH, while CSF HIV RNA decrease was the only marker associated with improved NPT-9 over time. Among PWH, higher CSF neopterin was most closely associated with higher NFL. Among PWOH, higher CSF MCP-1 was most closely associated with higher NFL. After antiretroviral therapy initiation, decrease in CSF MCP-1 was most closely associated with NFL decrease.

CONCLUSION

Monocyte-associated CSF biomarkers are highly associated with neuronal damage in both PWH and PWOH. More research is needed to evaluate whether therapies targeting monocyte-associated inflammation may ameliorate HIV-associated neurobehavioral diseases.

Sex-specific associations between cerebrospinal fluid inflammatory marker levels and cognitive function in antiretroviral treated people living with HIV in rural Uganda

People with HIV (PWH) taking antiretroviral therapy (ART) have persistent cognitive impairment. The prevalence of cognitive impairment is higher in women with HIV (WWH) compared to men with HIV (MWH), possibly due to sex differences in immune function. Here we report sex differences in cerebrospinal fluid (CSF) immune markers in relation to cognitive performance. A subset of 83 PWH on ART (52% WWH; mean age = 37.6 years, SD = 7.9) from the Rakai community cohort study Cohort and Rakai Health Sciences Program supported clinics in rural Uganda completed a neuropsychological (NP) assessment and a lumbar puncture. CSF was used to measure 16 cytokines/chemokines. Individual NP test z-scores were generated based on local normative data. A series of least absolute shrinkage and selection operator (lasso) regressions examined associations between CSF inflammatory markers and NP outcomes. Overall, there were no sex differences in CSF inflammatory marker levels. However, MWH displayed more associations between inflammatory markers and cognitive performance than WWH. Among MWH, inflammatory markers were associated with a number of cognitive domains, including attention, processing speed, fluency, executive function, learning and memory. MIP-1β, INF-γ, GM-CSF, IL-7 and IL-12p70 were associated with multiple domains. Among WWH, few inflammatory markers were associated cognition. Degree of associations between CSF inflammatory biomarkers and cognitive performance varied by sex in this young, ART-treated, Ugandan cohort. Further investigation into sex-specific inflammatory mechanisms of cognitive impairment among PWH is warranted to inform sex-specific management strategies.

Neurocognitive impairment in Spanish-speaking Latinos living with HIV in the US: Application of the neuropsychological norms for the US-Mexico border region in Spanish (NP-NUMBRS)

Objective Latinos in the US are at increased risk for HIV-associated neurocognitive impairment (NCI). Most studies of US Latinos living with HIV have included primarily English-speakers only. We investigated the rate, pattern, and correlates of HIV-associated NCI in native Spanish-speaking Latinos living in the US near the Mexican border. Methods Participants included 407 native Spanish-speaking Latinos (Age: M = 37.65, SD = 10.0; Education: M = 10.75, SD = 4.1; 53% male): 153 persons living with HIV (PLWH; 56% AIDS) and 254 healthy controls. All participants completed comprehensive neuropsychological assessments in Spanish. Raw neuropsychological test scores from seven domains were converted to demographically-adjusted T-scores using norms developed with healthy controls. Global and domain NCI were defined per established criteria. Among PLWH we applied norms developed for non-Hispanic (NH) Whites and Blacks, and investigated correlates of global NCI, including HIV disease characteristics and psychiatric comorbidities. Results Utilizing population specific norms, rates of global NCI were significantly higher among PLWH (39%) than healthy controls (17%), comparable to previously published rates. In contrast, rates of global NCI in the same group of PLWH were significantly different when NH White norms (63%, p < 0.0001) and NH Black norms were used (18%, p < 0.0001). Among PLWH without a history of lifetime substance use disorder, more years of antiretroviral exposure were significantly associated with decreased rates of global NCI. Conclusions Present findings lend support to the validity of newly developed norms for native Spanish-speakers living near the US-Mexico border, and underscore the importance of utilizing appropriate norms to accurately identify HIV-associated NCI.

Peripheral immune dysregulation in the ART era of HIV-associated neurocognitive impairments: A systematic review

Human immunodeficiency virus-associated neurocognitive impairment (HANI) remains problematic despite the effective use of antiretroviral therapy (ART) and viral suppression. A dysregulated immune response contributes to the development of HANI but findings on the association between peripheral blood immune markers and HANI have been inconsistent. We therefore conducted a systematic review of studies of the association of peripheral blood immune markers with neurocognitive performance in ART experienced HIV-positive participants. Thirty-seven studies were eligible, including 12 longitudinal studies and 25 cross-sectional studies. Findings consistently show that HIV-positive participants have altered immune marker levels, including elevated markers of monocyte activation (neopterin, sCD14, sCD163) and inflammation (CCL2, IL-8, IL-18, IP-10, IFN-α, sTNFR-II and TNF-α). These elevated levels persist in HIV-positive participants despite ART. The majority of studies found associations of HANI with immune markers, including those linked to monocyte activation (sCD14 and sCD163) and inflammation (IL-18 and IP-10). Despite the heterogeneity of studies reviewed, due to the presence of raised peripheral markers, our narrative review provides evidence of chronic inflammation despite ART. The raised levels of these markers may suggest certain mechanisms are active, potentially those involved in the neuropathophysiology of HANI.

Afternoon distraction: a high-saturated-fat meal and endotoxemia impact postmeal attention in a randomized crossover trial

BACKGROUND

Saturated-fat intake and endotoxemia can impair cognition. However, their acute impact on cognitive performance is unknown.

OBJECTIVE

This study assessed the impact of 2 high-fat meals and endotoxemia on attention.

METHODS

In this double-blind, randomized crossover trial, 51 women (n = 32 breast cancer survivors, n = 19 noncancer controls; mean ± SD age: 53 ± 8 y) completed the Continuous Performance Test (CPT) and had their blood drawn to assess endotoxemia markers LPS binding protein (LBP), soluble CD14 (sCD14), and the LBP to sCD14 ratio 1 h prior to eating either a high-saturated-fat meal or a high-oleic-sunflower-oil meal. Women again completed the CPT 5 h postmeal. At 1 to 4 wk later, women completed the same protocol but consumed the other meal.

RESULTS

In adjusted models, women had more difficulty distinguishing target stimuli from distractors after consuming the high-saturated-fat meal than they did after the oleic-sunflower-oil meal (B = 4.44, SE = 1.88, P = 0.02). Women with higher baseline LBP had less consistent response times (B = 0.002, SE = 0.0008, P = 0.04). Those with higher LBP and LBP:sCD14 were less able to sustain their attention throughout the entire CPT, as reflected by their progressively slower (B = 0.002, SE = 0.0006, P = 0.003; and B = 2.43, SE = 0.090, P = 0.008, respectively) and more erratic (B = 0.003, SE = 0.0008, P < 0.0001; and B = 3.29, SE = 1.17, P = 0.006, respectively) response times. Additionally, women with higher baseline LBP or sCD14 were less able to maintain or increase response speeds at higher interstimulus intervals (B = 0.002, SE = 0.0006, P = 0.02; and B = 0.006, SE = 0.003, P = 0.03, respectively), indicating greater difficulty adapting to changing task demands. Significant meal type by LBP and LBP:sCD14 interactions emerged (P < 0.05), such that high LBP and LBP:sCD14 erased between-meal cognitive differences, uniformly impairing performance.

CONCLUSIONS

These results suggest that higher LBP, sCD14, and LBP:sCD14 and saturated-fat intake individually and jointly influence attention. Endotoxemia may override the relative cognitive benefit of healthier oil choices.This trial is registered at clinicaltrials.gov as NCT04247763.

Elevated Plasma Levels of sCD14 and MCP-1 Are Associated With HIV Associated Neurocognitive Disorders Among Antiretroviral-Naive Individuals in Nigeria

BACKGROUND

Mononuclear cells play key roles in the pathogenesis of HIV-associated neurocognitive disorders (HAND). Limited studies have looked at the association of markers of monocyte activation with HAND in Africa. We examined this association among HIV-1-infected patients in Nigeria.

METHOD

A total of 190 HIV-infected treatment-naive participants with immune marker data were included in this cross-sectional study. Plasma levels of soluble CD14 (sCD14), soluble CD163, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), and neopterin were measured. Demographically adjusted T scores obtained from a 7-domain neuropsychological test battery were generated, and functional status was assessed using activities of daily living questionnaire. Participants were classified as unimpaired, having asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND), or HIV-associated dementia (HAD) in line with the "Frascati" criteria.

RESULTS

Thirty-two participants (16.8%) had ANI, 14 (7.4%) had MND, whereas none had HAD. In multivariable linear regression analyses, after adjusting for age, gender, education, CD4 count, and viral load, mean levels of sCD14 were higher among those with ANI and MND as compared with the unimpaired (P = 0.033 and 0.023, respectively). Similarly, the mean level of MCP-1 was greater among those with HAND as compared with the unimpaired (P = 0.047). There were also trends for higher levels of sCD163 and TNF-α among females with MND in univariable analyses.

CONCLUSIONS

Levels of monocyte activation markers correlate with the severity of impairment among individuals with HAND. The mechanisms that underlie these effects and the potential role of gender require further study.

Early Inflammatory Signatures Predict Subsequent Cognition in Long-Term Virally Suppressed Women With HIV

Immunologic function is an important determinant of cognition. Here we examined the contribution of early immune signatures to cognitive performance among HIV-infected, virally suppressed women (HIV+VS) and in HIV-uninfected (HIV-) women. Specifically, we measured serum inflammatory markers, developed combinatory immune signatures, and evaluated their associations with cognition. Forty-nine HIV+VS women in the Women’s Interagency HIV Study (WIHS) who achieved viral suppression shortly after effective antiretroviral therapy (ART) initiation, and 56 matched HIV− women were selected. Forty-two serum inflammatory markers were measured within 2 years of effective ART initiation for HIV+VS women, and at an initial timepoint for HIV− women. The same inflammatory markers were also measured approximately 1, 7, and 12 years later for all women. Of the 105 women with complete immune data, 83 (34 HIV+VS, 49 HIV−) also had cognitive data available 12 years later at ≥1 time points (median = 3.1). We searched for combinatory immune signatures by adapting a dynamic matrix factorization analytic method that builds upon Tucker decomposition followed by Ingenuity^® Pathway Analysis to facilitate data interpretation. Seven combinatory immune signatures emerged based on the Frobenius residual. Three signatures were common between HIV+VS and HIV− women, while four signatures were unique. These inflammatory signatures predicted subsequent cognitive performance in both groups using mixed-effects modeling, but more domain-specific associations were significant in HIV+VS than HIV− women. Leukocyte influx into brain was a major contributor to cognitive function in HIV+VS women, while T cell exhaustion, inflammatory response indicative of depressive/psychiatric disorders, microglial activity, and cytokine signaling predicted both global and domain-specific performance for HIV− women. Our findings suggest that immune signatures may be useful diagnostic, prognostic, and immunotherapeutic targets predictive of subsequent cognitive performance. Importantly, they also provide insight into common and distinct inflammatory mechanisms underlying cognition in HIV− and HIV+VS women.

Plasma Cystatin C Associates With HIV-Associated Neurocognitive Disorder but Is a Poor Diagnostic Marker in Antiretroviral Therapy-Treated Individuals

OBJECTIVE

To examine associations between plasma cystatin C and neurocognitive impairment (NCI) and its performance as a diagnostic marker before and during initial antiretroviral therapy (ART).

METHODS

Multivariable logistic regression and generalized estimating equations examined associations with NCI, determined by neuropsychological measurements, in participants of a 48-week randomized clinical trial of initial ART. Receiver operator characteristic curves examined diagnostic models of NCI.

RESULTS

Cystatin C was associated with NCI before ART [odds ratio (OR) 3.4 (95% CI: 1.2 to 9.4) for each 2-fold increase in baseline levels] and during 48 weeks of ART, in models that excluded baseline measurements [OR 3.0 (1.2 to 7.8) for each 2-fold increase in time-updated levels]. The strength of association increased with more severe impairment using HIV-associated neurocognitive disorder criteria [OR 2.2 (0.8 to 6.0) with asymptomatic NCI and OR 4.0 (1.5 to 11.0) with mild neurocognitive disorder or HIV-associated dementia vs. no impairment, for each 2-fold increase in time-updated levels] or by global development score [OR 2.6 (1.1 to 6.3) with mild impairment and OR 4.6 (1.1 to 18.9) with moderate or severe impairment vs. no impairment]. Cystatin C performed poorly as a diagnostic marker for NCI, however, with an area under the receiver operator characteristic curve of 0.58 at baseline and 0.54 at week 48.

CONCLUSIONS

Higher plasma cystatin C levels were significantly associated with NCI, but these levels did not seem to be useful as a diagnostic marker for this condition.

Brief Report: Body Mass Index and Cognitive Function Among HIV-1-Infected Individuals in China, India, and Nigeria

BACKGROUND

Risk of cognitive impairment is increased among persons with high or low body mass index in HIV- and HIV+ populations in resource-rich settings. We examined this association among HIV+ patients in 3 resource-limited settings.

METHODS

This secondary analysis included data of 761 HIV+ volunteers pooled from 3 prospective cohort studies conducted in China (n = 404; 53%), India (n = 200; 26%), and Nigeria (n = 157; 21%). World Health Organization (WHO) weight classifications were based on body mass index. T scores, adjusted for demographics and practice effects, were derived from a 7-domain neuropsychological battery. Neurocognitive impairment (NCI) was defined as global deficit score of ≥0.5.

RESULTS

Overall, prevalence of NCI at baseline was 27.7% (similar across all cohorts). The overweight/obese and underweight constituted 37.3% and 15.5% of the total participants, respectively. In a multivariable logistic regression of pooled longitudinal data, adjusting for clinical and demographic variables, the odds of global NCI were 38% higher among the overweight/obese as compared to normal weight participants [odds ratio: 1.38 (95% confidence interval: 1.1 to 1.72); P = 0.005]. Similarly, the odds of global NCI were 39% higher among the underweight as compared to normal weight participants [odds ratio: 1.39 (95% confidence interval: 1.03 to 1.87); P = 0.029].

CONCLUSIONS

NCI among HIV-1-infected patients was more prevalent in both overweight/obese and underweight than normal weight individuals in 3 resource-limited settings, confirming observations in resource-rich settings. Mechanisms underlying these associations are unclear but likely differ for underweight and overweight persons.

HIV-Associated Neurocognitive Impairment in the Modern ART Era: Are We Close to Discovering Reliable Biomarkers in the Setting of Virological Suppression?

The prevalence of the most severe forms of HIV-associated neurocognitive disorders (HAND) is decreasing due to worldwide availability and high efficacy of antiretroviral treatment (ART). However, several grades of HIV-related cognitive impairment persist with effective ART and remain a clinical concern for people with HIV (PWH). The pathogenesis of these cognitive impairments has yet to be fully understood and probably multifactorial. In PWH with undetectable peripheral HIV-RNA, the presence of viral escapes in cerebrospinal fluid (CSF) might explain a proportion of cases, but not all. Many other mechanisms have been hypothesized to be involved in disease progression, in order to identify possible therapeutic targets. As potential indicators of disease staging and progression, numerous biomarkers have been used to characterize and implicate chronic inflammation in the pathogenesis of neuronal injuries, such as certain phenotypes of activated monocytes/macrophages, in the context of persistent immune activation. Despite none of them being disease-specific, the correlation of several CSF cellular biomarkers to HIV-induced neuronal damage has been investigated. Furthermore, recent studies have been evaluating specific microRNA (miRNA) profiles in the CSF of PWH with neurocognitive impairment (NCI). The aim of the present study is to review the body of evidence on different biomarkers use in research and clinical settings, focusing on PWH on ART with undetectable plasma HIV-RNA.

Neurocognitive dysfunction in HIV-infected youth: investigating the relationship with immune activation

BACKGROUND

HIV-infected individuals are at increased risk of neurocognitive impairment compared to the general population. Studies suggest that, despite combination antiretroviral therapy (cART), HIV infection causes immune activation which results in neural damage; however, few data exist in HIV-infected youth.

METHODS

HIV-infected youth 8-26-years-old on cART with virological suppression were prospectively enrolled along with healthy controls. Neurocognitive performance was assessed by age-appropriate Wechsler Intelligence Scales. Soluble and cellular markers of T-lymphocyte and monocyte activation were measured by ELISA and flow cytometry, respectively.

RESULTS

45 HIV-infected subjects and 21 controls were enrolled. Markers of T-cell and monocyte activation were higher in the HIV-infected subjects compared to controls, but proportions of inflammatory and patrolling monocytes were similar. Although there were no significant differences in neurocognitive scores between the HIV-infected and control groups, scores were low-average for four of five testing domains for the HIV-infected subjects and average for all five in the controls, and % of HIV-infected subjects with scores classified as 'low average' or below was higher than in the controls. Variables most associated with neurocognitive performance among HIV-infected subjects included activated CD4⁺ T-cells (% CD4+CD38+HLA-DR), monocyte activation (soluble CD14), HIV duration, age and sex.

CONCLUSIONS

HIV-infected youth on cART with virological suppression show subtle evidence of neurocognitive impairment compared to healthy controls, and increased immune activation appears to play a role. Additional studies are needed to develop strategic interventions beyond cART to potentially improve neurocognitive performance and/or minimize further impairment in this vulnerable population. ClinicalTrials.gov Identifier: NCT01523496.

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.

Cerebrospinal fluid extracellular vesicles and neurofilament light protein as biomarkers of central nervous system injury in HIV-infected patients on antiretroviral therapy

Objective:

The relationship of cerebrospinal fluid (CSF) extracellular vesicles to neurocognitive impairment (NCI) in HIV-infected individuals is unclear. Here, we characterize CSF extracellular vesicles and their association with central nervous system (CNS) injury related biomarkers [neurofilament light (NFL), S100B, neopterin] and NCI in HIV-positive individuals on combination antiretroviral therapy (cART).

Design:

A cross-sectional and longitudinal study of CSF samples from HIV-positive individuals on cART.

Methods:

NFL, S100B and neopterin were measured by ELISA in 190 CSF samples from 112 individuals (67 HIV-positive and 45 HIV-negative). CSF extracellular vesicles were isolated and characterized by electron microscopy, nanoparticle tracking analysis, immunoblotting for exosome markers (CD9, CD63, CD81, FLOT-1) and ELISA for HLA-DR.

Results:

HIV-positive individuals had median age 52 years, 67% with suppressed plasma viral load (< 50 copies/ml), median CD4⁺ nadir 66 cells/μl and CD4⁺ cell count 313 cells/μl. CSF NFL, S100B and neopterin levels were higher in HIV-positive vs. HIV-negative individuals, and nonsuppressed vs. suppressed HIV-positive individuals. Although CSF NFL and S100B levels were higher in NCI vs. unimpaired HIV-positive individuals (P < 0.05), only NFL was associated with NCI in adjusted models (P < 0.05). CSF extracellular vesicles were increased in HIV-positive vs. HIV-negative individuals, and NCI vs. unimpaired HIV-positive individuals (P < 0.05), and correlated positively with NFL (P < 0.001). HLA-DR was enriched in CSF extracellular vesicles from HIV-positive individuals with NCI (P < 0.05), suggesting that myeloid cells are a potential source of CSF extracellular vesicles during HIV infection.

Conclusion:

Increased CSF extracellular vesicles correlate with neuronal injury biomarker NFL in cART-treated HIV-positive individuals with neurocognitive impairment, suggesting potential applications as novel biomarkers of CNS injury.

Impaired insulin sensitivity is associated with worsening cognition in HIV-infected patients

OBJECTIVE

To determine the association of insulin sensitivity and metabolic status with declining cognition in HIV-infected individuals.

METHODS

We conducted targeted clinical and metabolic measures in longitudinal plasma samples obtained from HIV-infected patients enrolled in the Central Nervous System HIV Anti-Retroviral Therapy Effects Research Study (CHARTER). Findings were validated with plasma samples from the Multicenter AIDS Cohort Study (MACS). Patients were grouped according to longitudinally and serially assessed cognitive performance as having stably normal or declining cognition.

RESULTS

Patients with declining cognition exhibited baseline hyperinsulinemia and elevated plasma c-peptide levels with normal c-peptide/insulin ratios, suggesting that insulin production was increased, but insulin clearance was normal. The association of hyperinsulinemia with worsening cognition was further supported by low high-density lipoprotein (HDL), high low-density lipoprotein/HDL ratio, and elevated cholesterol/HDL ratio compared to patients with stably normal cognition.

CONCLUSIONS

These findings suggest that hyperinsulinemia and impaired insulin sensitivity are associated with cognitive decline in antiretroviral therapy-treated HIV-infected patients.

Cognitive Function Among Antiretroviral Treatment-Naive Individuals Infected With Human Immunodeficiency Virus Type 1 Subtype G Versus CRF02_AG in Nigeria

Background

Human immunodeficiency virus type 1 (HIV-1) subtype has been shown to be associated with disease progression. We compared cognitive function between individuals infected with HIV-1 subtype G and CRF02_AG in Nigeria.

Methods

For this cross-sectional study, samples were analyzed from 146 antiretroviral-naive participants. Genotypic analysis of plasma HIV RNA was performed by nested polymerase chain reaction of protease and reverse transcriptase genes, and sequences were aligned with curated HIV-1 subtype references. Cognitive status was determined using demographically adjusted T scores and global deficit score (GDS) obtained from a comprehensive neuropsychological test battery.

Results

A total of 76 (52.1%) participants were infected with CRF02_AG, 48 (32.8%) with subtype G, and 22 (15.1%) with other HIV-1 strains. In a multivariable linear regression adjusting for plasma HIV RNA, CD4 count, and depression score, mean global T score was lower among subtype G-infected compared with CRF02_AG-infected participants (mean difference, -3.0 [95% confidence interval {CI}, -5.2, to -.7]; P = .011). Also, T scores were significantly lower among subtype G- than CRF02_AG-infected participants for the speed of information processing, executive function, and verbal fluency ability domains. Adjusting for similar variables in a logistic regression, the odds of global cognitive impairment (GDS ≥0.5) were 2.2 times higher among subtype G compared with CRF02_AG-infected participants (odds ratio, 2.2 [95% CI, .9-5.4]; P = .078).

Conclusions

Cognitive performance was significantly worse among antiretroviral-naive individuals with HIV-1 subtype G vs CRF02_AG infection. Further studies are required to characterize the mechanistic basis for these differences.

Aged Chinese-origin rhesus macaques infected with SIV develop marked viremia in absence of clinical disease, inflammation or cognitive impairment

BACKGROUND

Damage to the central nervous system during HIV infection can lead to variable neurobehavioral dysfunction termed HIV-associated neurocognitive disorders (HAND). There is no clear consensus regarding the neuropathological or cellular basis of HAND. We sought to study the potential contribution of aging to the pathogenesis of HAND. Aged (range = 14.7-24.8 year) rhesus macaques of Chinese origin (RM-Ch) (n = 23) were trained to perform cognitive tasks. Macaques were then divided into four groups to assess the impact of SIVmac251 infection (n = 12) and combined antiretroviral therapy (CART) (5 infected; 5 mock-infected) on the execution of these tasks.

RESULTS

Aged SIV-infected RM-Ch demonstrated significant plasma viremia and modest CSF viral loads but showed few clinical signs, no elevations of systemic temperature, and no changes in activity levels, platelet counts or weight. Concentrations of biomarkers of acute and chronic inflammation such as soluble CD14, CXCL10, IL-6 and TNF-α are known to be elevated following SIV infection of young adult macaques of several species, but concentrations of these biomarkers did not shift after SIV infection in aged RM-Ch and remained similar to mock-infected macaques. Neither acute nor chronic SIV infection or CART had a significant impact on accuracy, speed or percent completion in a sensorimotor test.

CONCLUSIONS

Viremia in the absence of a chronic elevated inflammatory response seen in some aged RM-Ch is reminiscent of SIV infection in natural disease resistant hosts. The absence of cognitive impairment during SIV infection in aged RM-Ch might be in part attributed to diminishment of some facets of the immunological response. Additional study encompassing species and age differences is necessary to substantiate this hypothesis.

Markers of Microbial Translocation and Immune Activation Predict Cognitive Processing Speed in Heavy-Drinking Men Living with HIV

HIV infection and alcohol use disorder are associated with deficits in neurocognitive function. Emerging evidence points to pro-inflammatory perturbations of the gut-brain axis as potentially contributing to neurocognitive impairment in the context of HIV and chronic heavy alcohol use. This study examined whether plasma markers of microbial translocation (LPS) from the gastrointestinal tract and related immune activation (sCD14, EndoCAb) were associated with neurocognition in 21 men living with HIV who were virally suppressed on antiretroviral therapy. All participants met federal criteria for heavy drinking and were enrolled in a randomized controlled trial (RCT) of a brief alcohol intervention. This secondary analysis utilized blood samples and cognitive scores (learning, memory, executive function, verbal fluency, and processing speed) obtained at baseline and three-month follow-up of the RCT. In generalized estimating equation models, LPS, sCD14, and EndoCAb individually were significant predictors of processing speed. In a model with all biomarkers, higher LPS and sCD14 both remained significant predictors of lower processing speed. These preliminary findings suggest that inflammation stemming from HIV and/or alcohol could have negative effects on the gut-brain axis, manifested as diminished processing speed. Associations of microbial translocation and immune activation with processing speed in heavy-drinking PLWH warrant further investigation in larger-scale studies.

Modifications in acute phase and complement systems predict shifts in cognitive status of HIV-infected patients

BACKGROUND

The prevalence of HIV-associated neurocognitive disorders (HAND) has not changed considerably in the last two decades. Potent antiretroviral therapy has shifted the severity of HAND to milder phenotypes, but excess morbidity and mortality continue to be associated with HAND. Changes in numerous markers of immune function, inflammation, and cellular stress have been repeatedly associated with HAND, but the underlying systems that drive these changes have not been identified.

METHOD

In this study, we used systems informatics to interrogate the cerebrospinal fluid proteomic content of longitudinal samples obtained from HIV-infected adults with stably unimpaired, stably impaired, worsening, or improving neurocognitive performance.

RESULTS AND CONCLUSION

The patterns of change in cerebrospinal fluid protein content implicated the induction of acute phase and complement systems as important regulators of neurocognitive status. Worsening neurocognitive performance was preceded by induction of acute phase and complement systems, whereas improving neurocognitive performance was preceded by a downregulation of these systems.

Genome-wide association study of HIV-associated neurocognitive disorder (HAND): A CHARTER group study

HIV-associated neurocognitive disorder (HAND) often complicates HIV infection despite combination antiretroviral therapy (ART) and may be influenced by host genomics. We performed a genome-wide association study (GWAS) of HAND in 1,050 CNS HIV Anti-Retroviral Therapy Effects Research (CHARTER) Study participants. All participants underwent standardized, comprehensive neurocognitive, and neuromedical assessments to determine if they had cognitive impairment as assessed by the Global Deficit Score (GDS), and individuals with comorbidities that could confound diagnosis of HAND were excluded. Neurocognitive outcomes included GDS-defined neurocognitive impairment (NCI; binary GDS, 366 cases with GDS ≥ 0.5 and 684 controls with GDS < 0.5, and GDS as a continuous variable) and Frascati HAND definitions that incorporate assessment of functional impairment by self-report and performance-based criteria. Genotype data were obtained using the Affymetrix Human SNP Array 6.0 platform. Multivariable logistic or linear regression-based association tests were performed for GDS-defined NCI and HAND. GWAS results did not reveal SNPs meeting the genome-wide significance threshold (5.0 × 10-8 ) for GDS-defined NCI or HAND. For binary GDS, the most significant SNPs were rs6542826 (P = 8.1 × 10-7 ) and rs11681615 (1.2 × 10-6 ), both located on chromosome 2 in SH3RF3. The most significant SNP for continuous GDS was rs11157436 (P = 1.3 × 10-7 ) on chromosome 14 in the T-cell-receptor alpha locus; three other SNPs in this gene were also associated with binary GDS (P ≤ 2.9 × 10-6 ). This GWAS, conducted among ART-era participants from a single cohort with robust neurological phenotyping, suggests roles for several biologically plausible loci in HAND that deserve further exploration. © 2017 Wiley Periodicals, Inc.

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.

European Mitochondrial DNA Haplogroups are Associated with Cerebrospinal Fluid Biomarkers of Inflammation in HIV Infection

Background:

Mitochondrial DNA (mtDNA) haplogroups are ancestry-related patterns of single-nucleotide polymorphisms that are associated with differential mitochondrial function in model systems, neurodegenerative diseases in HIV-negative populations, and chronic complications of HIV infection, including neurocognitive impairment. We hypothesized that mtDNA haplogroups are associated with neuroinflammation in HIV-infected adults.

Methods:

CNS HIV Antiretroviral Therapy Effects Research (CHARTER) is a US-based observational study of HIV-infected adults who underwent standardized neurocognitive assessments. Participants who consented to DNA collection underwent whole blood mtDNA sequencing, and a subset also underwent lumbar puncture. IL-6, IL-8, TNF-α (high-sensitivity), and IP-10 were measured in cerebrospinal fluid (CSF) by immunoassay. Multivariable regression of mtDNA haplogroups and log-transformed CSF biomarkers were stratified by genetic ancestry using whole-genome nuclear DNA genotyping (European [EA], African [AA], or Hispanic ancestry [HA]), and adjusted for age, sex, antiretroviral therapy (ART), detectable CSF HIV RNA, and CD4 nadir. A total of 384 participants had both CSF cytokine measures and genetic data (45% EA, 44% AA, 11% HA, 22% female, median age 43 years, 74% on ART).

Results:

In analyses stratified by the 3 continental ancestry groups, no haplogroups were significantly associated with the 4 biomarkers. In the subgroup of participants with undetectable plasma HIV RNA on ART, European haplogroup H participants had significantly lower CSF TNF-α (P = 0.001).

Conclusions:

Lower CSF TNF-α may indicate lower neuroinflammation in the haplogroup H participants with well-controlled HIV on ART.

Immune activation and neuroinflammation in alcohol use and HIV infection: evidence for shared mechanisms

BACKGROUND

Emerging research points to innate immune mechanisms in the neuropathological and behavioral consequences of heavy alcohol use. Alcohol use is common among people living with HIV infection (PLWH), a chronic condition that carries its own set of long-term effects on brain and behavior. Notably, neurobiological and cognitive profiles associated with heavy alcohol use and HIV infection share several prominent features. This observation raises questions about interacting biological mechanisms as well as compounded impairment when HIV infection and heavy drinking co-occur.

OBJECTIVE AND METHOD

This narrative overview discusses peer-reviewed research on specific immune mechanisms of alcohol that exhibit apparent potential to compound the neurobiological and psychiatric sequelae of HIV infection. These include microbial translocation, systemic immune activation, blood-brain barrier compromise, microglial activation, and neuroinflammation.

RESULTS

Clinical and preclinical evidence supports overlapping mechanistic actions of HIV and alcohol use on peripheral and neural immune systems. In preclinical studies, innate immune signaling mediates many of the detrimental neurocognitive and behavioral effects of alcohol use. Neuropsychopharmacological research suggests potential for a feed-forward cycle in which heavy drinking induces innate immune signaling, which in turn stimulates subsequent alcohol use behavior.

CONCLUSION

Alcohol-induced immune activation and neuroinflammation are a serious health concern for PLWH. Future research to investigate specific immune effects of alcohol in the context of HIV infection has potential to identify novel targets for therapeutic intervention.

Alcohol use predicts elevation in inflammatory marker soluble CD14 in men living with HIV

Independently, HIV infection and heavy alcohol use increase microbial translocation (MT) of gut products into systemic circulation. MT and consequent immune response have been linked to chronic inflammation and a host of negative health outcomes in individuals living with HIV. However, previous research has not systematically investigated the immune correlates of heavy drinking specifically within the HIV-positive population. This pilot study investigated MT and immune activation as a function of alcohol use in 21 HIV-positive men who met NIAAA criteria for heavy drinking. Participants averaged 46.7 ± 8.5 (mean ± standard deviation) years of age, 12.2 ± 9.2 years since HIV diagnosis, 337 ± 158 CD4 nadir, and 643 ± 245 current CD4 count. All participants were virologically suppressed on antiretroviral therapy. Data on alcohol use and immune function were collected at baseline and three-month follow-up. Plasma concentrations of markers of MT and immune activation (lipopolysaccharide (LPS), soluble CD14 (sCD14), endotoxin core antibody immunoglobulin M (EndoCAb)) were measured using enzyme-linked immunosorbent assays. Generalized estimating equation models tested alcohol use variables as predictors of LPS, sCD14, and EndoCAb levels. Greater quantity and frequency of drinking significantly predicted higher sCD14 levels (p's < .01). Conversely, longer duration of abstinence from alcohol significantly predicted lower sCD14 levels (p < .001). These results remained significant after controlling for age, HIV duration, smoking status, current CD4 count, CD4 nadir, and antiretroviral drug type. In addition, participants with ≥50% relative reduction in drinks per week showed a significant decrease (p < .05) in sCD14 from baseline to three-month follow-up. This pilot study provides preliminary evidence that heavy drinking may increase a key inflammatory marker in HIV-infected individuals with suppressed infection.

Latent Toxoplasma Infection and Higher Toxoplasma gondii Immunoglobulin G Levels Are Associated With Worse Neurocognitive Functioning in HIV-Infected Adults

BACKGROUND

 Human immunodeficiency virus (HIV)-associated neurocognitive disorders persist despite suppressive antiretroviral therapy (ART). Because latent Toxoplasma infection (LTI) may adversely impact brain function, we investigated its impact on neurocognitive impairment (NCI) in people living with HIV disease.

METHODS

 Two hundred sixty-three HIV-infected adults underwent comprehensive neurocognitive assessments and had anti-Toxoplasma gondii immunoglobulin G (anti-Toxo IgG) measured by qualitative and quantitative enzyme-linked immunosorbent assays.

RESULTS

 Participants were mostly middle-aged white men who were taking ART (70%). LTI was detected in 30 (11.4%) participants and was associated with a significantly greater prevalence of global NCI (LTI positive [LTI⁺] = 57% and LTI negative [LTI^-] = 34%) (odds ratio, 1.67; 95% confidence interval, 1.17-2.40; P = .017). Deficits were more prevalent in the LTI⁺ vs the LTI^- group in 6 of 7 cognitive domains with statistical significance reached for delayed recall (P < .01). The probability of NCI increased with higher CD4⁺ T-cell counts among LTI⁺ individuals but with lower CD4⁺ T-cell counts in LTI^- persons. A strong correlation (r = .93) between anti-Toxo IgG levels and global deficit score was found in a subgroup of 9 patients. Biomarkers indicative of central nervous system inflammation did not differ between LTI⁺ and LTI^- participants.

CONCLUSIONS

 In this cross-sectional analysis, LTI was associated with NCI, especially in those with higher CD4⁺ T-cell counts. Longitudinal studies to investigate the role of neuroinflammation and neuronal injury in LTI patients with NCI and trials of anti-Toxoplasma therapy should be pursued.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cerebrospinal fluid interferon alpha levels correlate with neurocognitive impairment in ambulatory HIV-Infected individuals

HIV-associated neurocognitive disorders (HANDs) continue to be common and are associated with increased morbidity and mortality. However, the underlying mechanisms in the combination antiretroviral therapy (cART) era are not fully understood. Interferon alpha (IFNα) is an antiviral cytokine found to be elevated in the cerebrospinal fluid (CSF) of individuals with advanced HIV-associated dementia in the pre-cART era. In this cross-sectional study, we investigated the association between IFNα and neurocognitive performance in ambulatory HIV-infected individuals with milder impairment. An eight-test neuropsychological battery representing six cognitive domains was administered. Individual scores were adjusted for demographic characteristics, and a composite neuropsychological score (NPT-8) was calculated. IFNα and CSF neurofilament light chain (NFL) levels were measured using enzyme-linked immunosorbent assay (ELISA). There were 15 chronically infected participants with a history of significant immunocompromise (median nadir CD4+ of 49 cells/μl). Most participants were neurocognitively impaired (mean global deficit score of 0.86). CSF IFNα negatively correlated with three individual tests (Trailmaking A, Trailmaking B, and Stroop Color-Word) as well as the composite NPT-8 score (r = -0.67, p = 0.006). These negative correlations persisted in multivariable analyses adjusting for chronic hepatitis B and C. Additionally, CSF IFNα correlated strongly with CSF NFL, a marker of neuronal damage (rho = 0.748, p = 0.0013). These results extend findings from individuals with severe HIV-associated dementia in the pre-cART era and suggest that IFNα may continue to play a role in HAND pathogenesis during the cART era. Further investigation into the role of IFNα is indicated.

CSF/plasma HIV-1 RNA discordance even at low levels is associated with up-regulation of host inflammatory mediators in CSF

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Discordant HIV in CSF is associated with raised inflammatory mediators in CSF.

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CSF mediators are raised with discordance both at high and low levels.

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Discordance on ultrasensitive testing can also be also associated with raised mediators.

Introduction

HIV-1 RNA can be found at higher levels in cerebrospinal fluid (CSF) than in plasma, termed CSF/plasma discordance. The clinical significance of CSF/plasma discordance is not known and the degree of discordance considered important varies. We aimed to determine whether a panel of CSF cytokines, chemokines and associated mediators were raised in patients with CSF/plasma discordance at different levels.

Methods

A nested case-control study of 40 CSF samples from the PARTITION study. We used a cytometric bead array to measure CSF mediator concentrations in 19 discordant and 21 non-discordant samples matched for plasma HIV-1 RNA. Discordant samples were subdivided into ‘high discordance’ (>1log₁₀) and ‘low discordance’ (0.5–1log₁₀, or ultrasensitive discordance). CSF mediators significant in univariate analysis went forward to two-way unsupervised hierarchical clustering based on the patterns of relative mediator concentrations.

Results

In univariate analysis 19 of 21 CSF mediators were significantly higher in discordant than non-discordant samples. There were no significant differences between samples with high versus low discordance. The samples grouped into two clusters which corresponded to CSF/plasma discordance (p < 0.0001). In cluster one all mediators had relatively high abundance; this included 18 discordant samples and three non-discordant samples. In cluster two all mediators had relatively low abundance; this included 18 non-discordant samples and one non-discordant sample with ultrasensitive discordance only.

Conclusions

CSF/plasma discordance is associated with potentially damaging neuroinflammatory process. Patients with discordance at lower levels (ie. 0.5–1log₁₀) should also be investigated as mediator profiles were similar to those with discordance >1log₁₀. Sensitive testing may have a role to determine whether ultrasensitive discordance is present in those with low level CSF escape.

HIV-associated neurocognitive disorder--pathogenesis and prospects for treatment

In the past two decades, several advancements have improved the care of HIV-infected individuals. Most importantly, the development and deployment of combination antiretroviral therapy (CART) has resulted in a dramatic decline in the rate of deaths from AIDS, so that people living with HIV today have nearly normal life expectancies if treated with CART. The term HIV-associated neurocognitive disorder (HAND) has been used to describe the spectrum of neurocognitive dysfunction associated with HIV infection. HIV can enter the CNS during early stages of infection, and persistent CNS HIV infection and inflammation probably contribute to the development of HAND. The brain can subsequently serve as a sanctuary for ongoing HIV replication, even when systemic viral suppression has been achieved. HAND can remain in patients treated with CART, and its effects on survival, quality of life and everyday functioning make it an important unresolved issue. In this Review, we describe the epidemiology of HAND, the evolving concepts of its neuropathogenesis, novel insights from animal models, and new approaches to treatment. We also discuss how inflammation is sustained in chronic HIV infection. Moreover, we suggest that adjunctive therapies--treatments targeting CNS inflammation and other metabolic processes, including glutamate homeostasis, lipid and energy metabolism--are needed to reverse or improve HAND-related neurological dysfunction.

The Interleukin-1 Balance During Encephalitis Is Associated With Clinical Severity, Blood-Brain Barrier Permeability, Neuroimaging Changes, and Disease Outcome

BACKGROUND

Encephalitis is parenchymal brain inflammation, commonly due to herpes simplex virus (HSV). Key host inflammatory mediators and their relationship to blood-brain barrier (BBB) permeability, neuroimaging changes, and disease outcome are poorly understood.

METHODS

We measured levels of 38 mediators in serum (n = 78) and cerebrospinal fluid (n = 37) specimens from patients with encephalitis, including 17 with disease due to HSV infection. Outcome measures were Glasgow coma and outcome scores; CSF to serum albumin ratio, reflecting BBB permeability; and, in patients with HSV infection, magnetic resonance imaging-based temporal lobe volume.

RESULTS

Serum interleukin 1 receptor antagonist (IL-1RA) levels were elevated in patients with a good outcome (P= .004). Among patients infected with HSV, the ratio of CSF IL-1β to IL-1RA was associated with a worse outcome (P= .009); a ratio of ≥0.55 pg/mL had high specificity and sensitivity for a poor outcome (100% and 83%;P= .015). Temporal lobe volume had a negative correlation with serum IL-1RA level (P= .012) and a positive correlation with serum IL-1α level (P= .0003) and CSF IL-1β level (P= .007). A normal coma score was associated with an elevated interleukin 10 (IL-10) level in serum specimens from HSV-infected patients (P= .007) and CSF specimens from all patients (P= .016); the IL-10 level correlated inversely with BBB permeability (P= .005).

CONCLUSIONS

A proinflammatory cytokine response is associated with greater clinical severity, BBB permeability, and neuroimaging damage during encephalitis. IL-1 antagonists should be investigated as adjunctive treatment in encephalitis.

Plasma and Cerebrospinal Fluid Biomarkers Predict Cerebral Injury in HIV-Infected Individuals on Stable Combination Antiretroviral Therapy

OBJECTIVES

HIV-associated brain injury persists despite combination antiretroviral therapy, but contributing factors remain poorly understood. We postulated that inflammation-associated biomarkers will be associated with cerebral injury on proton magnetic resonance spectroscopy in chronically HIV-infected subjects.

METHODS

Five biomarkers were measured in 197 HIV-infected subjects: soluble CD14, MCP-1, IP-10, MIP-1β, and fractalkine. Levels of N-acetyl aspartate (NAA), Choline (Cho), Myoinositol (MI), Glutamate + Glutamine (Glx), and Creatine (Cr) were acquired in the midfrontal cortex (MFC), frontal white matter, and basal ganglia (BG). Predictive models were built through linear regression, and the best models were chosen using the Akaike Information Criterion.

RESULTS

Increases in plasma or CSF MCP-1 were associated with lower NAA/Cr in the MFC and BG, whereas metabolite changes in the frontal white matter for NAA/Cr, GlxCr, and Cho/Cr were explained almost exclusively by a single factor, sCD14. Plasma and CSF levels of this factor were also significantly associated with Glx/Cr in MFC and BG. Higher CSF FKN was associated with higher NAA/Cr in BG. Best predictors for higher Cho/Cr in BG and MFC were CSF sCD14 and CSF MIP-1β. Plasma and CSF IP-10 were only associated with Cho/Cr in MFC. Of the 3 models that simultaneously accounted for both plasma and CSF, there were more associations between CSF biomarkers and magnetic resonance spectroscopy metabolites.

CONCLUSIONS

Markers of inflammation and immune activation, in particular MCP-1 and sCD14, predominantly reflecting CNS sources, contribute to the persistence of brain injury in a metabolite and region-dependent manner in chronically HIV-infected patients on stable combination antiretroviral therapy.

CSF biomarkers of monocyte activation and chemotaxis correlate with magnetic resonance spectroscopy metabolites during chronic HIV disease

Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) persist despite combination antiretroviral therapy (cART), supporting the need to better understand HIV neuropathogenesis. Magnetic resonance spectroscopy (MRS) of the brain has demonstrated abnormalities in HIV-infected individuals despite cART. We examined the associations between MRS metabolites and selected cerebrospinal fluid (CSF) biomarkers reflecting monocyte/macrophage activation and chemotaxis. A multicenter cross-sectional study involving five sites in the USA was conducted. The following CSF biomarkers were measured: soluble CD14 (sCD14), monocyte chemotactic protein-1 (MCP-1), interferon inducible protein 10 (IP-10), and stromal cell-derived growth factor 1 alpha (SDF-1α). The following MRS metabolites were measured from basal ganglia (BG), frontal white matter (FWM), and frontal gray matter (FGM): N-acetylaspartate (NAA), myo-inositol (MI), choline (Cho), and creatine (Cr). CSF biomarkers were compared to absolute MRS metabolites as well as metabolite/Cr ratios using linear regression. Eighty-three HIV-infected individuals were included, 78 % on cART and 37 % with HAND. The most robust positive correlations were between MCP-1 and Cho in BG (R (2) 0.179, p < 0.001) as well as MCP-1 and MI in FWM (R (2) 0.137, p = 0.002). Higher Cr levels in FWM were associated with MCP-1 (R (2) 0. 075, p = 0.01) and IP-10 (R (2) 0.106, p = 0.003). Comparing biomarkers to MRS metabolite/Cr ratios impacted some relationships, e.g., higher sCD14 levels were associated with lower Cho/Cr ratios in FGM (R (2) 0.224, p < 0.001), although higher MCP-1 levels remained associated with Cho/Cr in BG. These findings provide evidence that monocyte activation and chemotaxis continue to contribute to HIV-associated brain abnormalities in cART-treated individuals.

Activation of Cannabinoid Type Two Receptors (CB2) Diminish Inflammatory Responses in Macrophages and Brain Endothelium

Chronic neuroinflammatory disorders (such as HIV associated neurodegeneration) require treatment that decreases production of inflammatory factors by activated microglia and macrophages and protection of blood brain barrier (BBB) injury secondary to activation of brain endothelium. Cannabioid type 2 receptor (CB2) is highly expressed on macrophages and brain microvasular enndothelial cells (BMVEC) and is upregulated in inflammation and HIV infection. It has been shown that CB2 activation dampened inflammatory responses in macrophages and BMVEC. In this study, we assessed by PCR array the expression of a wide range of genes increased in macrophages and BMVEC in inflammation. TNFα treatment upregulated 33 genes in primary human BMVEC, and two highly selective CB2 agonists diminished expression of 31 and 32 genes. These results were confirmed by functional assays (BBB protection after inflammatory insult and decreased migration of monocytes across BMVEC monolayers after CB2 stimulation). Similarly, CB2 stimulation in primary human macrophages led to the suppression of 35 genes out of the 50 genes upregulated by LPS. Such changes in gene expression paralleled diminished secretion of proinflammatory factors. These results indicate the potential utility of CB2 agonists for the treatment of neuroinflammation.

Cerebrospinal fluid metabolomics implicate bioenergetic adaptation as a neural mechanism regulating shifts in cognitive states of HIV-infected patients

OBJECTIVES

To identify prognostic surrogate markers for change in cognitive states of HIV-infected patients.

DESIGN

Longitudinal cerebrospinal fluid (CSF) samples were collected from 98 HIV-infected patients identified by temporal change in cognitive states classified as normal, stably impaired, improving and worsening.

METHODS

The metabolic composition of CSF was analysed using H nuclear magnetic resonance (H NMR) spectroscopy that focused on energy metabolites. Metabolic biomarkers for cognitive states were identified using multivariate partial least squares regression modelling of the acquired spectra, combined with nonparametric analyses of metabolites with clinical features.

RESULTS

Multivariate modelling and cross-validated recursive partitioning identified several energy metabolites that, when combined with clinical variables, classified patients based on change in neurocognitive states. Prognostic identification for worsening was achieved with four features that included no change in a detectable plasma viral load, elevated citrate and acetate; decreased creatine, to produce a model with a predictive accuracy of 92%, sensitivity of 88% and 96% specificity. Prognosis for improvement contained seven features that included first visit age less than 47 years, new or continued use of antiretrovirals, elevated glutamine and glucose; decreased myo-inositol, β-glucose and creatinine to generate a model with a predictive accuracy of 92%, sensitivity of 100% and specificity of 84%.

CONCLUSION

These CSF metabolic results suggest that worsening cognitive status in HIV-infected patients is associated with increased aerobic glycolysis, and improvements in cognitive status are associated with a shift to anaerobic glycolysis. Dietary, lifestyle and pharmacologic interventions that promote anaerobic glycolysis could protect the brain in setting of HIV infection with combined antiretroviral therapy.

Investigating the role of ankyrin-rich membrane spanning protein in human immunodeficiency virus type-1 Tat-induced microglia activation

Long-term persistence of human immunodeficiency virus type-1 (HIV) in the central nervous system (CNS) results in mild to severe neurocognitive impairment in a significant proportion of the HIV-infected population. These neurological deficits are known as HIV-associated neurocognitive disorders (HAND). Microglia are CNS-resident immune cells that are directly infected by HIV and consequently secrete proinflammatory molecules that contribute to HIV-induced neuroinflammation. Indeed, the number of activated macrophage and microglia in the brain is more highly correlated with cognitive impairment than the amount of neuronal apoptosis. Ankyrin-rich membrane spanning protein (ARMS/Kidins220) is a multidomain transmembrane protein that is involved with neurotrophin signaling in the CNS. We have previously established the role of ARMS in mediating neuronal survival via a neurotrophin-dependent mechanism. Recent reports also have suggested that ARMS is involved with cell signaling in multiple immune cell types. In this study, we aim to investigate the role of ARMS in HIV Tat-mediated microglial cell activation by employing in vitro methods. Following ARMS depletion by a lentivirus encoding ARMS-specific short hairpin RNA (shRNA), we observed a marked reduction in the HIV Tat-induced proinflammatory response, associated with loss of tumor necrosis factor alpha production and nuclear factor-kappa B (NF-κB) activation. Furthermore, co-immunoprecipitation studies suggested that ARMS physically interacts with inhibitory kappa B kinase subunits in order to facilitate NF-κB activation. Our results establish the role of ARMS in microglial activation by HIV Tat and warrant additional studies to better understand these molecular mechanisms, which may uncover novel therapeutic targets for the treatment of HAND.

Reduced neural specificity in middle-aged HIV+ women in the absence of behavioral deficits

In the post combination antiretroviral therapy (cART) era, the prevalence of mild forms of HIV-associated neurocognitive disorders (HAND) in individuals with HIV-infection remains high. There is a pressing need to find biomarkers that can aid clinical assessment of HAND, especially in those with mild or no neurocognitive symptoms. Here we hypothesized that a reduction in neural specificity, or the specificity of neuronal tuning, could serve as a potential biomarker of asymptomatic HAND. To directly test this hypothesis, we applied two advanced fMRI techniques to examine the difference in neural specificity between middle-aged HIV+ women and age-matched negative controls, with a focus on the fusiform face area (FFA), a critical region in face processing. Face discrimination performance was assessed outside of the scanner. While the behavioral performance of face discrimination was comparable between the two groups, a reduced neural specificity in the FFA of HIV-positive women was revealed by a novel fMRI analysis technique, local regional heterogeneity analysis, or H_corr, as well as an established technique, fMRI-rapid adaptation. In contrast, conventional fMRI techniques were insensitive to these early changes. These results suggest that, prior to the onset of detectable behavioral deficits, significant neuronal dysfunctions are already present in HIV+ individuals, and these early neuronal dysfunctions can be detected and assessed via neural specificity, which, in combining with the novel H_corr technique, has a strong potential to serve as a biomarker of asymptomatic HAND and other neurodegenerative diseases.

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We investigate early neuronal dysfunctions in cognitively normal HIV+ women.

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Conventional fMRI technique reveals normal neural activity in the FFA of HIV+ women.

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fMRI-adaptation reveals a decrease in neural specificity in the FFA of HIV+ women.

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H_corr, a novel fMRI technique, confirms the fMRI-adaptation results

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H_corr-estimated neural specificity might serve as a biomarker of asymptomatic HAND