Neuropathological sequelae of Human Immunodeficiency Virus and apathy: A review of neuropsychological and neuroimaging studies

Methamphetamine Enhancement of HIV-1 gp120-Mediated NLRP3 Inflammasome Activation and Resultant Proinflammatory Responses in Rat Microglial Cultures

Human Immunodeficiency Virus type 1 (HIV-1)-associated neurocognitive disorders (HANDs) remain prevalent in HIV-1-infected individuals despite the evident success of combined antiretroviral therapy (cART). The mechanisms underlying HAND prevalence in the cART era remain perplexing. Ample evidence indicates that HIV-1 envelope glycoprotein protein 120 (gp120), a potent neurotoxin, plays a pivotal role in HAND pathogenesis. Methamphetamine (Meth) abuse exacerbates HANDs, but how this occurs is not fully understood. We hypothesize that Meth exacerbates HANDs by enhancing gp120-mediated neuroinflammation. To test this hypothesis, we studied the effect of Meth on gp120-induced microglial activation and the resultant production of proinflammatory cytokines in primary rat microglial cultures. Our results show that Meth enhanced gp120-induced microglial activation, as revealed by immunostaining and Iba-1 expression, and potentiated gp120-mediated NLRP3 expression and IL-1β processing and release, as assayed by immunoblotting and ELISA. Meth also augmented the co-localization of NLRP3 and caspase-1, increased the numbers of NLRP3 puncta and ROS production, increased the levels of iNOS expression and NO production, and increased the levels of cleaved gasderminD (GSDMD-N; an executor of pyroptosis) in gp120-primed microglia. The Meth-associated effects were attenuated or blocked by MCC950, an NLRP3 inhibitor, or Mito-TEMPO, a mitochondrial superoxide scavenger. These results suggest that Meth enhances gp120-associated microglial NLRP3 activation and the resultant proinflammatory responses via mitochondria-dependent signaling.

Motivation levels and white matter microstructure in children living with HIV

Central nervous system involvement in HIV infection leads to neurobehavioural sequelae. Although apathy is a well-recognised symptom in adults living with HIV linked to alterations in brain structure, there is scarce research examining motivation in children living with HIV (CLWH). We used the Children's Motivation Scale (CMS; normative mean = 50, SD = 10) to assess motivation levels in 76 CLWH aged 6-16 years (63 on antiretroviral therapy [ART]; 13 ART-naïve slow progressors) in South Africa. Overall, CLWH scored low on the CMS (mean = 35.70 [SD = 5.87]). Motivation levels were significantly reduced in children taking ART compared to ART-naïve slow progressors (p = 0.02), but were not correlated with markers of HIV disease (CD4 + cell count or viral load), or neurocognitive function (p > 0.05). CMS scores were correlated with diffusion tensor imaging metrics of white matter microstructure in specific frontostriatal brain regions (p < 0.05). On multiple regression, associations with the anterior limb of the internal capsule, a subcortical white matter region, remained significant after adjusting for potential confounders. These findings suggest that reduced motivation may be an important neurobehavioural symptom in CLWH and may reflect changes in white matter microstructure of frontostriatal brain regions.

Methamphetamine enhancement of HIV-1 gp120-mediated NLRP3 inflammasome activation and resultant proinflammatory responses in rat microglial cultures

Background

Human Immunodeficiency Virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) remain prevalent in HIV-1-infected individuals despite the evident success of combined antiretroviral therapy (cART). The mechanisms under HAND prevalence in the cART era remain perplexing. Ample evidence indicates that HIV-1 envelope glycoprotein protein 120 (gp120), a potent neurotoxin, plays a pivotal role in the HAND pathogenesis. Methamphetamine (Meth) abuse exacerbates HAND. How Meth exacerbates HAND is not fully understood. This study was to test the hypothesis that Meth exacerbates HAND by enhancing gp120-mediated proinflammatory responses in the brain, worsening the pathogenesis of HAND.

Methods

Experiments were carried out on primary microglial cultures prepared from neonatal SD rats. The purity of microglia was determined by staining with anti-CD11b. Meth and gp120 were applied to microglial cultures. Microglial activation was revealed by immunostaining and Iba-1 expression. The protein expression levels of Pro-IL-1β, Il-1β, Iba-1, iNOS, NLRP3, GSDMD and GSDMD-N were detected by western blotting analyses. The levels of proinflammatory cytokine and NO production in the microglia culture supernatants were assayed by ELISA and Griess reagent systems, respectively. NLRP3 activation was uncovered by fluorescent microscopy images displaying NLRP3 puncta labeled by anti-NLRP3 antibody. NLRP3 co-localization with caspase-1 was labeled with antibodies. One-way ANOVA with post hoc Tukey's multiple comparison tests was employed for statistical analyses.

Results

Meth enhanced gp120-induced microglia activation revealed by immunostaining and Iba-1 expression, and potentiated gp120-mediated NLRP3 expression, IL-1β processing and release assayed by immunoblot and ELISA. Meth also augmented the co-localization of NLRP3 and caspase-1, increased the numbers of NLRP3 puncta and ROS production, elevated levels of iNOS expression and NO production, and enhanced levels of cleaved gasderminD (GSDMD-N, an executor of pyroptosis) in gp120-primed microglia. The Meth-associated effects were attenuated or blocked by MCC950, an NLRP3 inhibitor, or Mito-TEMPO, a mitochondrial superoxide scavenger, indicating the involvement of mitochondria in Meth enhancement of NLRP3 inflammasome activation in gp120-primed microglia.

Conclusions

These results suggest that Meth enhanced gp120-associated microglial NLRP3 activation and resultant proinflammatory responses via mitochondria-dependent signaling.

Anterior Insula Activation During Cardiac Interoception Relates to Depressive Symptom Severity in HIV-Positive and HIV-Negative Postmenopausal Women

OBJECTIVE

This study aimed to determine whether subclinical symptoms of depression in postmenopausal women are associated with blood oxygen level-dependent (BOLD) activity within the anterior insula during cardiac interoceptive awareness and whether this association differs for persons living with the human immunodeficiency virus (PWH).

METHOD

Twenty-three postmenopausal (mean [standard deviation] age = 56.5 [4.8] years) and 27 HIV-negative women (mean [standard deviation] age = 56.4 [8.0]) underwent functional magnetic resonance imaging while performing a heartbeat detection task. BOLD activation within the bilateral anterior insula based on the contrast of a heartbeat detection condition with and without a distracting tone was entered along with age, HIV status, and psychological stress into two multivariate regression models with self-reported depressive symptom severity as the outcome.

RESULTS

Depressive symptoms did not vary by HIV status, nor was there a main effect or interaction for PWH on insula BOLD activation. Depressive symptoms were positively associated with psychological stress for the left ( β = 0.310, t (49) = 2.352, p = .023) and right brain models ( β = 0.296, t (49) = 2.265, p = .028) as well as the magnitude of BOLD activation in the left insula ( β = 0.290, t (49) = 2.218, p = .032) and right insula ( β = 0.318, t (49) = 2.453, p = .018), respectively. Exploratory analyses revealed that greater magnitude of BOLD activation attributed to exteroceptive noise (tone) was also correlated with self-reported distrust and preoccupation with interoceptive sensations.

CONCLUSIONS

Results support an active interference model for interoceptive awareness wherein greater BOLD signal in the anterior insula in the presence of distracting exteroceptive stimuli may reflect greater prediction error, a feature of depression.

Relationship between reward-related evoked potentials and real-world motivation in older people living with human immunodeficiency virus

Apathy, a clinical disorder characterized by low motivation, is prevalent in people living with Human Immunodeficiency Virus (HIV). It affects mental and physical health-related quality-of-life, medication adherence, and is associated with cognitive decline. However, the causes of apathy and the underlying brain mechanisms in HIV are unknown. Brain responses to reward may be relevant to understanding apathy and might serve as biomarkers for diagnosis or treatment response. Electroencephalogram (EEG) responses to gain and loss feedback in simple guessing tasks have been related to apathy in neurodegenerative conditions and healthy individuals. The primary aim of this study is to contribute evidence regarding the relationship between two EEG correlates of reward processing, the Reward Positivity, and the Feedback-P300, and real-world motivated behavior indicated by self-reported hours engaged in goal-directed leisure activities per week, in older individuals with well-controlled HIV infection. High-density EEG was collected from 75 participants while they performed a guessing task with gain or loss feedback. We found that a later component of reward processing, the Feedback-P300, was related to real-world engagement, while the earlier Reward Positivity was not. The Feedback-P300 measured with EEG holds promise as a biomarker for motivated behavior in older people living with HIV. These findings lay the groundwork for a better understanding of the neurobiology of apathy in this condition.

Does effort-cost decision-making relate to real-world motivation in people living with HIV?

INTRODUCTION

Low motivation is frequent in older people with HIV, yet poorly understood. Effort-cost decision-making (ECDM) tasks inspired by behavioral economics have shown promise as indicators of motivation or apathy. These tasks assess the willingness to exert effort to earn a monetary reward, providing an estimate of the subjective "cost" of effort for each participant. Here we sought evidence for a relationship between ECDM task performance and self-reported motivation in a cross-sectional study involving 80 middle-aged and older people with well-controlled HIV infection, a chronic health condition with a high burden of mental and cognitive health challenges.

METHODS

Participants attending a regular follow-up visit for a Canadian longitudinal study of brain health in HIV completed a computerized ECDM task and a self-report measure of motivation. Other brain health measures were available, collected for the parent study (cognition, depression, anxiety, and vitality, as well as self-reported time spent on real-world leisure activities).

RESULTS

Contrary to our hypothesis, we found no relationship between ECDM performance and self-reported motivation. However, those willing to accept higher effort in the ECDM task also reported more time engaged in real-world activities. This association had a small-to-moderate effect size.

CONCLUSIONS

The behavioral economics construct of subjective cost of effort, measured with a laboratory ECDM task, does not relate to motivation in people living with chronic HIV. However, the task shows some relationship with real-world goal-directed behavior, suggesting this construct has potential clinical relevance. More work is needed to understand how the subjective cost of effort plays out in clinical symptoms and everyday activities.

Methamphetamine augments HIV-1 gp120 inhibition of synaptic transmission and plasticity in rat hippocampal slices: Implications for methamphetamine exacerbation of HIV-associated neurocognitive disorders

Methamphetamine (Meth) abuse and human immunodeficiency virus type 1 (HIV-1) infection are two major public health problems worldwide. Being frequently comorbid with HIV-1 infection, Meth abuse exacerbates neurocognitive impairment in HIV-1-infected individuals even in the era of combined antiretroviral therapy. While a large body of research have studied the individual effects of Meth and HIV-1 envelope glycoprotein 120 (gp120) in the brain, far less has focused on their synergistic influence. Moreover, it is well-documented that the hippocampus is the primary site of spatial learning and long-term memory formation. Dysregulation of activity-dependent synaptic transmission and plasticity in the hippocampus is believed to impair neurocognitive function. To uncover the underlying mechanisms for increased incidence and severity of HIV-1-associated neurocognitive disorders (HAND) in HIV-1-infected patients with Meth abuse, we investigated acute individual and combined effects of Meth (20 μM) and gp120 (200 pM) on synaptic transmission and plasticity in the CA1 region of young adult male rat hippocampus, a brain region known to be vulnerable to HIV-1 infection. Our results showed that acute localized application of Meth and gp120 each alone onto the CA1 region reduced short-term dynamics of input-output responses and frequency facilitation, and attenuated long-term potentiation (LTP) induced by either high frequency stimulation or theta burst stimulation. A synergistic augmentation on activity-dependent synaptic plasticity was observed when Meth and gp120 were applied in combination. Paired-pulse facilitation results exhibited an altered facilitation ratio, suggesting a presynaptic site of action. Further studies revealed an involvement of microglia NLRP3 inflammasome activation in Meth augmentation of gp120-mediated attenuation of LTP. Taken together, our results demonstrated Meth augmented gp120 attenuation of LTP in the hippocampus. Since LTP is the accepted experimental analog of learning at the synaptic level, such augmentation may underlie Meth exacerbation of HAND observed clinically.

Apathy is not associated with a panel of biomarkers in older adults with HIV disease

OBJECTIVE

Apathy is prevalent in HIV disease and can significantly impact personal well-being; however, little is known about its neurobiological substrates in persons with HIV (PWH) disease.

METHODS

This cross-sectional, correlational study examined the association between apathy and several plasma biomarkers (tumor necrosis factor alpha, kynurenine, tryptophan, quinolinic acid, brain-derived neurotrophic factor, glial fibrillary acidic protein, neurofilament light chain, and phosphorylated tau at position threonine 181) in 109 PWH and 30 seronegative participants ages 50 and older. Apathy was measured with a composite score derived from subscales of the Frontal Systems Behavior Scale and the Profile of Mood States.

RESULTS

Multiple regressions showed that PWH had significantly greater severity of apathy symptoms, independent of both data-driven and conceptually-based covariates. Pairwise correlations in the PWH sample indicated that apathy was not significantly associated with any of the measured biomarkers and all of the effect sizes were small.

CONCLUSION

Findings suggest that apathy is not strongly associated with peripheral biomarkers of inflammation, neurotrophic support, or neurodegeneration in older PWH. Limitations of this study include the cross-sectional design, the use of self-report measures of apathy, and low rates of viremia. Longitudinal studies in more representative samples of PWH that include a more comprehensive panel of fluid biomarkers, informant and behavioral indicators of apathy, and relevant psychosocial factors might help to further clarify the neurobiological substrates of this complex neuropsychiatric phenomenon.

Apathetic symptoms and white matter integrity after traumatic brain injury

PRIMARY OBJECTIVE

The aim of the study was twofold. First, to study the relationship among apathy in the long term, initial clinical measures, and standard outcome scores after traumatic brain injury (TBI). Second, to describe white matter integrity correlates of apathy symptoms.

RESEARCH DESIGN

Correlational study. Methods and Procedures: Correlation and Bayesian networks analyses were performed in a sample of 40 patients with moderate to severe TBI in order to identify the relationship among clinical variables, functionality, and apathy. A diffusion tensor imaging study was developed in 25 participants to describe correlations between fractional anisotropy (FA) measures and apathetic symptoms.

MAIN OUTCOMES AND RESULTS

Correlation analysis revealed associations between pairs of variables as apathy in the long term and functional score at discharge from hospital. Bayesian network illustrated the relevant role of axonal injury mediating the relationship between apathy and initial clinical variables. FA in the superior longitudinal fasciculus, the inferior longitudinal fasciculus, and the internal capsule were negatively correlated with apathy measures. Widespread brain areas showed positive correlations between FA and apathy.

CONCLUSIONS

These results highlight the relevance of white matter integrity measures in initial assessment after TBI and its relationship with apathetic manifestations in the chronic phase.

Neuropsychiatric Disorders, Emotional Disturbances, and Their Associations with HIV-Associated Neurocognitive Disorder

The current chapter provides a critical and narrative review of recent research on the neuropsychiatric disorders, emotional disturbances, and their associations with neurocognitive functioning in people living with HIV infection. We review a range of neuropsychiatric disorders including depression and anxiety disorders, but also emotional disturbances, which can be partly distinguished from depression and anxiety (apathy, alexithymia, and emotional processing impairment). While reviewing the research into the neuropsychiatric disorders and HIV-associated neurocognitive disorders, we also cover the questions of self-reported cognitive symptoms evaluation and interpretation. The chapter includes research on the role of coping skills, perceived stress and response to stressful life events, and connections to neurocognitive impairment in people living with HIV. Promising non-pharmacological interventions are highlighted. The chapter concludes with the clinical implications on how to best consider neuropsychiatric disorders and cognitive symptoms for the diagnosis of HIV-associated neurocognitive disorders, as well as future research directions.

Chronic SSRI treatment reverses HIV-1 protein-mediated synaptodendritic damage

HIV-1 infection affects approximately 37 million individuals, and approximately 50% of seropositive individuals will develop symptoms of clinical depression and/or apathy. Dysfunctions of both serotonergic and dopaminergic neurotransmission have been implicated in the pathogenesis of motivational alterations. The present study evaluated the efficacy of a SSRI (escitalopram) in the HIV-1 transgenic (Tg) rat. Behavioral, neurochemical, and neuroanatomical outcomes with respect to HIV-1 and sex were evaluated to determine the efficacy of chronic escitalopram treatment. Escitalopram treatment restored function in each of the behavioral tasks that were sensitive to HIV-1-induced impairments. Further, escitalopram treatment restored HIV-1-mediated synaptodendritic damage in the nucleus accumbens; treatment with escitalopram significantly increased dendritic proliferation in HIV-1 Tg rats. However, restoration did not consistently occur with the neurochemical analysis in the HIV-1 rat. Taken together, these results suggest a role for SSRI therapies in repairing long-term HIV-1 protein-mediated neuronal damage and restoring function.

Atypical Resting-State Functional Connectivity Dynamics Correlate With Early Cognitive Dysfunction in HIV Infection

Purpose: Previous studies have shown that HIV affects striato-cortical regions, leading to persisting cognitive impairment in 30-70% of the infected individuals despite combination antiretroviral therapy. This study aimed to investigate brain functional dynamics whose deficits might link to early cognitive decline or immunologic deterioration. Methods: We applied sliding windows and K-means clustering to fMRI data (HIV patients with asymptomatic neurocognitive impairment and controls) to construct dynamic resting-state functional connectivity (RSFC) maps and identify states of their reoccurrences. The average and variability of dynamic RSFC, and the dwelling time and state transitioning of each state were evaluated. Results: HIV patients demonstrated greater variability in RSFC between the left pallidum and regions of right pre-central and post-central gyri, and between the right supramarginal gyrus and regions of the right putamen and left pallidum. Greater variability was also found in the frontal RSFC of pars orbitalis of the left inferior frontal gyrus and right superior frontal gyrus (medial). While deficits in learning and memory recall of HIV patients related to greater striato-sensorimotor variability, deficits in attention and working memory were associated with greater frontal variability. Greater striato-parietal variability presented a strong link with immunologic function (CD4+/CD8+ ratio). Furthermore, HIV-infected patients exhibited longer time and reduced transitioning in states typified by weaker connectivity in specific networks. CD4+T-cell counts of the HIV-patients were related to reduced state transitioning. Conclusion: Our findings suggest that HIV alters brain functional connectivity dynamics, which may underlie early cognitive impairment. These findings provide novel insights into our understanding of HIV pathology, complementing the existing knowledge.

Neuropsychological and neurophysiological correlates of fatigue in post-acute patients with neurological manifestations of COVID-19: Insights into a challenging symptom

More than half of patients who recover from COVID-19 experience fatigue. We studied fatigue using neuropsychological and neurophysiological investigations in post-COVID-19 patients and healthy subjects. Neuropsychological assessment included: Fatigue Severity Scale (FSS), Fatigue Rating Scale, Beck Depression Inventory, Apathy Evaluation Scale, cognitive tests, and computerized tasks. Neurophysiological examination was assessed before (PRE) and 2 min after (POST) a 1-min fatiguing isometric pinching task and included: maximum compound muscle action potential (CMAP) amplitude in first dorsal interosseous muscle (FDI) following ulnar nerve stimulation, resting motor threshold, motor evoked potential (MEP) amplitude and silent period (SP) duration in right FDI following transcranial magnetic stimulation of the left motor cortex. Maximum pinch strength was measured. Perceived exertion was assessed with the Borg-Category-Ratio scale. Patients manifested fatigue, apathy, executive deficits, impaired cognitive control, and reduction in global cognition. Perceived exertion was higher in patients. CMAP and MEP were smaller in patients both PRE and POST. CMAP did not change in either group from PRE to POST, while MEP amplitudes declined in controls POST. SP duration did not differ between groups PRE, increased in controls but decreased in patients POST. Patients' change of SP duration from PRE to POST was negatively correlated to FSS. Abnormal SP shortening and lack of MEP depression concur with a reduction in post-exhaustion corticomotor inhibition, suggesting a possible GABA_B-ergic dysfunction. This impairment might be related to the neuropsychological alterations. COVID-19-associated inflammation might lead to GABAergic impairment, possibly representing the basis of fatigue and explaining apathy and executive deficits.

HIV Infection and Neurocognitive Disorders in the Context of Chronic Drug Abuse: Evidence for Divergent Findings Dependent upon Prior Drug History

The fronto-striatal circuitry, involving the nucleus accumbens, ventral tegmental area, and prefrontal cortex, mediates goal-directed behavior and is targeted by both drugs of abuse and HIV-1 infection. Acutely, both drugs and HIV-1 provoke increased dopamine activity within the circuit. However, chronic exposure to drugs or HIV-1 leads to dysregulation of the dopamine system as a result of fronto-striatal adaptations to oppose the effects of repeated instances of transiently increased dopamine. Specifically, chronic drug use leads to reduced dopaminergic tone, upregulation of dopamine transporters, and altered circuit connectivity, sending users into an allosteric state in which goal-directed behaviors are dysregulated (i.e., addiction). Similarly, chronic exposure to HIV-1, even with combination antiretroviral therapy (cART), dysregulates dopamine and dopamine transporter function and alters connectivity of the fronto-striatal circuit, contributing to apathy and clinical symptoms of HIV-1 associated neurocognitive disorders (HAND). Thus, in a drug user also exposed to HIV-1, dysregulation of the fronto-striatal dopamine circuit advances at an exacerbated rate and appears to be driven by mechanisms unique from those seen with chronic drug use or HIV-1 exposure alone. We posit that the effects of drug use and HIV-1 infection on microglia interact to drive the progression of motivational dysfunction at an accelerated rate. The current review will therefore explore how the fronto-striatal circuit adapts to drug use (using cocaine as an example), HIV-1 infection, and both together; emphasizing proper methods and providing future directions to develop treatments for pathologies disrupting goal-directed behaviors and improve clinical outcomes for affected patients. Graphical Abstract Drug use and HIV-1 in the fronto-striatal circuit. Drugs of abuse and HIV-1 infection both target the fronto-striatal circuit which mediates goal-directed behavior. Acutely, drugs and HIV-1 increase dopamine activity; in contrast chronic exposure produces circuit adaptions leading to dysregulation, addiction and/or apathy. Comorbid drug use and HIV-1 infection may interact with microglia to exacerbate motivational dysregulation.

Cortical Thickness in Alcohol Dependent Patients With Apathy

OBJECTIVES

Many studies reported structural brain changes in patients with alcohol dependence (PADs). However, no studies identified structural correlates of apathy that might aggravate alcohol misuse. Here, we explored regional differences in cortical thickness in PADs relative to healthy controls (HCs), and examined the potential correlation of regional thickness with the severity of apathy.

METHODS

Magnetic resonance imaging data were collected from 33 male PADs and 35 male age- and education-matched HCs. We used the FreeSurfer software to investigate group differences in cortical thickness across 148 regions. Apathy was evaluated using the Lille Apathy Rating Scale-Informant (LARS-I). Regression analyses examined the relationship between cortical thickness of regions of interest and apathy score in PADs.

RESULTS

Compared to HCs, PADs showed significant decreases in the cortical thickness of occipito-temporal cortex (OTC), including the left middle occipital gyrus and occipital pole, right superior occipital gyri, and bilateral lingual gyrus; bilateral superior parietal cortex (SPC), including the right intraparietal sulcus; and bilateral inferior parietal cortex (IPC). Furthermore, the cortical thickness of all of the three regions was negatively correlated with the apathy total scores. The cortical thickness of the IPC was also negatively correlated with the action initiation subscore of the LARS-I.

CONCLUSIONS

The current results suggest the thickness of bilateral parietal and occipital temporal cortices as neural markers of apathy in PADs. These findings add to the literature by identifying the neural bases of a critical clinical feature of individuals with alcoholism.

Selective monoaminergic and histaminergic circuit dysregulation following long-term HIV-1 protein exposure

Between 30 and 60% of HIV-seropositive individuals develop symptoms of clinical depression and/or apathy. Dopamine and serotonin are associated with motivational alterations; however, histamine is less well studied. In the present study, we used fast-scan cyclic voltammetry in HIV-1 transgenic (Tg) rats to simultaneously analyze the kinetics of nucleus accumbens dopamine (DA), prefrontal cortical serotonin (5-HT), and hypothalamic histamine (HA). For voltammetry, subjects were 15 HIV-1 Tg (7 male, 8 female) and 20 F344/N (11 male, 9 female) adult rats. Both serotonergic and dopaminergic release and reuptake kinetics were decreased in HIV-1 Tg animals relative to controls. In contrast, rates of histamine release and reuptake increased in HIV-1 Tg rats. Additionally, we used immunohistochemical (IHC) methods to identify histaminergic neurons in the tuberomammillary nucleus (TMN) of the hypothalamus. For IHC, subjects were 9 HIV-1 Tg (5 male, 4 female) and 9 F344/N (5 male, 4 female) adult rats. Although the total number of TMN histaminergic cells did not differ between HIV-1 Tg rats and F344/N controls, a significant sex effect was found, with females having an increased number of histaminergic neurons, relative to males. Collectively, these findings illustrate neurochemical alterations that potentially underlie or exacerbate the pathogenesis of clinical depression and/or apathy in HIV-1.

Optimal treatment of HIV-associated neurocognitive disorders: myths and reality. A critical review

Background:

The aim of this study was to review the clinical data on the effectiveness of the pharmacotherapy of HIV-associated neurocognitive disorders (HANDs).

Methods:

A literature search of PubMed was performed (from January 1996 to October 2018) using the terms: ‘HIV-associated neurocognitive disorders’, ‘HIV-associated dementia’, ‘mild neurocognitive disorder (MND)’, ‘asymptomatic neurocognitive impairment (ANI)’, ‘adjuvant therapies’, ‘antiretroviral treatment (cART)’, ‘neurotoxicity’, ‘cART intensification’, ‘fluid markers’, ‘cerebrospinal fluid’, ‘protease inhibitors’, ‘nonnucleoside reverse transcriptase inhibitor’, ‘nucleoside reverse transcriptase inhibitors’, and ‘integrase strand transfer inhibitors’. Additional references were identified from a review of literature citations. All English language clinical studies of adjunctive therapies and neuronal markers were selected in order to evaluate a closer relationship between the early involvement and the onset of cognitive decline. We identified 407 relevant studies, of which 248 were excluded based on abstract analysis. Finally, we analyzed 35 articles, organizing the results by cART, adjuvant and neuronal markers (total of 7716 participants).

Results:

It is important to inform clinicians about the importance of accurate phenotyping of HIV patients, incorporating an array of markers relevant to HAND pathophysiology, in order to assess the individual’s risk and potential response to future personalized antiretroviral treatment

Conclusion:

So far, no clinical trials of HAND therapies are effective beyond optimal suppression of HIV replication in the central nervous system. Combination of validated neuronal markers should be used to distinguish between milder HAND subtypes and improve efficiency of clinical trials, after strict control of confounders.

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

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

Therapy Adherence and Emotional Awareness and Regulation in Persons With Human Immunodeficiency Virus

Adherence to antiretroviral therapy (ART) is a key issue for people with human immunodeficiency virus. Optimal adherence leads to benefits in terms of survival and quality of life, which do not occur with incomplete adherence. One factor that may influence adherence to ART is emotional unawareness deficits. To explore this possibility, we assessed emotional deficits and measured adherence in 100 adults using both self-report and viral load testing. Results showed that people classified as adherent in both measurements were more likely to have a greater awareness of their own emotions. Participants classified as nonadherent were more likely to have a reduced ability to recognize the emotions of others. Difficulty in recognizing one's own emotions, otherwise known as alexithymia, and impairment of the ability to recognize other's emotions may contribute to nonadherence to ART. Consequently, after repeated studies to confirm the findings, it can be considered a target for psychological therapies aimed at increasing adherence.

Mechanisms of neuropathogenesis in HIV and HCV: similarities, differences, and unknowns

HIV and hepatitis C virus (HCV) have both been associated with cognitive impairment. Combination antiretroviral therapy (cART) has dramatically changed the nature of cognitive impairment in HIV-infected persons, while the role of direct-acting antivirals (DAA) in neurocognition of HCV-infected individuals remains unclear. Also, whether HIV and HCV interact to promote neurocognitive decline or whether they each contribute an individual effect continues to be an open question. In this work, we review the virally mediated mechanisms of HIV- and HCV-mediated neuropathogenesis, with an emphasis on the role of dual infection, and discuss observed changes with HIV viral suppression and HCV functional cure on neurocognitive impairments.

The anatomy of apathy: A neurocognitive framework for amotivated behaviour

Apathy is a debilitating syndrome associated with many neurological disorders, including several common neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease, and focal lesion syndromes such as stroke. Here, we review neuroimaging studies to identify anatomical correlates of apathy, across brain disorders. Our analysis reveals that apathy is strongly associated with disruption particularly of dorsal anterior cingulate cortex (dACC), ventral striatum (VS) and connected brain regions. Remarkably, these changes are consistent across clinical disorders and imaging modalities. Review of the neuroimaging findings allows us to develop a neurocognitive framework to consider potential mechanisms underlying apathy. According to this perspective, an interconnected group of brain regions - with dACC and VS at its core - plays a crucial role in normal motivated behaviour. Specifically we argue that motivated behaviour requires a willingness to work, to keep working, and to learn what is worth working for. We propose that deficits in any one or more of these processes can lead to the clinical syndrome of apathy, and outline specific approaches to test this hypothesis. A richer neurobiological understanding of the mechanisms underlying apathy should ultimately facilitate development of effective therapies for this disabling condition.

HIV-1 proteins dysregulate motivational processes and dopamine circuitry

Motivational alterations, such as apathy, in HIV-1+ individuals are associated with decreased performance on tasks involving frontal-subcortical circuitry. We used the HIV-1 transgenic (Tg) rat to assess effect of long-term HIV-1 protein exposure on motivated behavior using sucrose (1–30%, w/v) and cocaine (0.01–1.0 mg/kg/infusion) maintained responding with fixed-ratio (FR) and progressive-ratio (PR) schedules of reinforcement. For sucrose-reinforced responding, HIV-1 Tg rats displayed no change in EC₅₀ relative to controls, suggesting no change in sucrose reinforcement but had a downward shifted concentration-response curves, suggesting a decrease in response vigor. Cocaine-maintained responding was attenuated in HIV-1 Tg rats (FR1 0.33 mg/kg/infusion and PR 1.0 mg/kg/infusion). Dose-response tests (PR) revealed that HIV-1 Tg animals responded significantly less than F344 control rats and failed to earn significantly more infusions of cocaine as the unit dose increased. When choosing between cocaine and sucrose, control rats initially chose sucrose but with time shifted to a cocaine preference. In contrast, HIV-1 disrupted choice behaviors. DAT function was altered in the striatum of HIV-1 Tg rats; however, prior cocaine self-administration produced a unique effect on dopamine homeostasis in the HIV-1 Tg striatum. These findings of altered goal directed behaviors may determine neurobiological mechanisms of apathy in HIV-1+ patients.

Associations between Depressive Symptomatology and Neurocognitive Impairment in HIV/AIDS

OBJECTIVE

Mood disorders and neurocognitive impairments are debilitating conditions among patients with HIV/AIDS. How these comorbidities interact and their relationships to systemic factors remain uncertain. Herein, we investigated factors contributing to depressive symptomatology (DS) in a prospective cohort of patients with HIV/AIDS in active care that included neuropsychological assessment.

METHODS

Among patients with HIV/AIDS receiving combination antiretroviral therapy (cART) and ongoing clinical assessments including measures of sleep, health-related quality of life (HQoL), neuropsychological testing, and mood evaluation (Patient Health Questionnaire-9 [PHQ-9]) were performed. Univariate and multivariate analyses were applied to the data.

RESULTS

In 265 persons, 3 categories of DS were established: minimal (PHQ-9: 0-4; n = 146), mild (PHQ-9: 5-9; n = 62), and moderate to severe (PHQ-9: 10+; n = 57). Low education, unemployment, diabetes, reduced adherence to treatment, HIV-associated neurocognitive disorders (HAND), low health-related quality of life (HQoL), reduced sleep times, and domestic violence were associated with higher PHQ-9 scores. Motor impairment was also associated with more severe DS. In a multinomial logistic regression model, only poor HQoL and shorter sleep duration were predictive of moderate to severe depression. In this multivariate model, the diagnosis of HAND and neuropsychological performance (NPz) were not predictive of DS.

CONCLUSIONS

Symptoms of depression are common (45%) in patients with HIV/AIDS and represent a substantial comorbidity associated with multiple risk factors. Our results suggest that past or present immunosuppression and HAND are not linked to DS. In contrast, sleep quality and HQoL are important variables to consider in screening for mood disturbances among patients with HIV/AIDS and distinguishing them from neurocognitive impairments.

Incidence of Neurological Disorders Among HIV-Infected Individuals With Universal Health Care in Taiwan From 2000 to 2010

OBJECTIVE

To determine the incidence of and factors associated with neurological disorders in a large Taiwanese cohort of HIV-infected persons with free access to highly active antiretroviral therapy (HAART).

DESIGN

A retrospective population-based cohort study was conducted using the National Health Insurance Research Database for the years 2000-2010.

METHODS

We identified 13,316 HIV-positive persons from 2000 through 2010. We used direct standardization to calculate age-adjusted and sex-adjusted incidence rates based on the 2000 World Health Organization world standard population. Factors associated with neurological disorders were analyzed using a Cox proportional hazards model.

RESULTS

The standardized incidence of neurological disorders among HIV-infected persons increased from 22.16 per 1000 person-years in 2000 to 25.23 per 1000 person-years in 2010. Cognitive disorders increased significantly from 0.36 per 1000 person-years in 2001 to 7.44 per 1000 person-years in 2010 (trend P < 0.001). The rate of neurological disorders increased with age ≥55 years [adjusted hazard ratios (AHRs) 2.54, 95% confidence interval (CI): 1.89 to 3.40], hypertension (AHR 1.41, 95% CI: 1.12 to 1.76), substance abuse (AHR 1.65, 95% CI: 1.36 to 2.02), opportunistic infection (AHR 1.76, 95% CI: 1.47 to 2.11), syphilis (AHR 1.27, 95% CI: 1.10 to 1.47), and emergency department visits >5 (AHR 2.41, 95% CI: 1.96 to 2.97). The incidence of neurological disorders was negatively associated with adherence to HAART (adherence ≥85% AHR: 0.79, 95% CI: 0.64 to 0.97).

CONCLUSIONS

The rising incidence of cognitive disorders among HIV-positive persons highlights the need to provide routine neurological evaluations at clinical visits. Receiving HAART with adherence ≥85% contributes to a reduced risk of neurological disorders.

Effort and neuropsychological performance in HIV-infected individuals on stable combination antiretroviral therapy

The expression of cognitive symptoms associated with HIV varies over time and across individuals. This pattern may reflect transient contextual factors, including the degree of effort exerted by individuals undergoing cognitive testing. The present study examined whether effort corresponds to the expression of persistent HIV-related cognitive impairment among individuals receiving combination antiretroviral therapy (cART). HIV+ individuals (n = 111) averaged 48.2 (14.9) years of age and 13.0 (2.7) years of education and HIV- individuals (n = 92) averaged 34.9 (17.2) years of age and 13.5 (1.9) years of education. Participants completed a neuropsychological battery and a clinically validated measure of effort (Test of Memory Malingering, trial 1). Results revealed that the vast majority of HIV+ (85%) and HIV- (89%) individuals performed above published guidelines for adequate effort. Furthermore, the expression of cognitive impairment in HIV was not related to effort performance. The results were unchanged when examining HIV+ individuals with and without viral suppression. Finally, disability and disability-seeking status, and a proxy measure of apathy did not correspond to effort levels in HIV+ individuals. These findings suggest that variability in the expression of cognitive impairment in the cART era is unlikely to represent overt effort failures or other confounds unrelated to the disease. Persistent cognitive impairment in HIV likely represents historical and/or ongoing disease mechanisms despite otherwise successful treatment.

Neural Correlates for Apathy: Frontal-Prefrontal and Parietal Cortical- Subcortical Circuits

Apathy is an uncertain nosographical entity, which includes reduced motivation, abulia, decreased empathy, and lack of emotional involvement; it is an important and heavy-burden clinical condition which strongly impacts in everyday life events, affects the common daily living abilities, reduced the inner goal directed behavior, and gives the heaviest burden on caregivers. Is a quite common comorbidity of many neurological disease, However, there is no definite consensus on the role of apathy in clinical practice, no definite data on anatomical circuits involved in its development, and no definite instrument to detect it at bedside. As a general observation, the occurrence of apathy is connected to damage of prefrontal cortex (PFC) and basal ganglia; “emotional affective” apathy may be related to the orbitomedial PFC and ventral striatum; “cognitive apathy” may be associated with dysfunction of lateral PFC and dorsal caudate nuclei; deficit of “autoactivation” may be due to bilateral lesions of the internal portion of globus pallidus, bilateral paramedian thalamic lesions, or the dorsomedial portion of PFC. On the other hand, apathy severity has been connected to neurofibrillary tangles density in the anterior cingulate gyrus and to gray matter atrophy in the anterior cingulate (ACC) and in the left medial frontal cortex, confirmed by functional imaging studies. These neural networks are linked to projects, judjing and planning, execution and selection common actions, and through the basolateral amygdala and nucleus accumbens projects to the frontostriatal and to the dorsolateral prefrontal cortex. Therefore, an alteration of these circuitry caused a lack of insight, a reduction of decision-making strategies, and a reduced speedness in action decision, major responsible for apathy. Emergent role concerns also the parietal cortex, with its direct action motivation control. We will discuss the importance of these circuits in different pathologies, degenerative or vascular, acute or chronic.

Vocal emotion processing deficits in HIV-infected individuals

We aimed to explore the brain imaging correlates of vocal emotion processing in a group of HIV+ individuals and to compare the vocal emotion processing of HIV+ individuals with a group of healthy adults. We conducted multiple linear regressions to determine the cerebral correlates of a newly designed vocal emotion processing test in a sub-group of HIV+ individuals who completed the cerebral magnetic resonance scan (n = 36). Separately, we test whether the association between our test scores and each cerebral measure persisted regardless of the presence of neurocognitive impairment. We also calculated differences in average test scores between the total HIV+ group (n = 100) and a healthy adult group (n = 46). We found a positive association between the test scores and several brain area volumes: right frontal, temporal and parietal lobes, bilateral thalamus, and left hippocampus. We found a negative association between inflammatory markers in frontal white matter and the test scores. After controlling by neurocognitive impairment, several brain area volumes remained positively associated to the prosody test scores. Moreover, the whole HIV+ sample had significantly poorer test scores than healthy adults, but only in the subset of HIV+ individuals with neurocognitive impairment. For the first time, our results suggest that cerebral dysfunctions in particular brain areas involved in the processing of emotional auditory stimuli may occur in HIV+ individuals. These results highlight the need for broad characterization of the neuropsychological consequence of HIV brain damages.

Neurobehavioral Manifestations of Human Immunodeficiency Virus/AIDS: Diagnosis and Treatment

Behavioral disorders are common in persons infected with human immunodeficiency virus (HIV). The differential includes preexisting psychiatric diseases, substance abuse, direct effects of HIV infection, opportunistic infection, and the adverse effects of medical therapies. Many patients have more than one contributing or comorbid problem to explain these behavioral changes. The differential should always include consideration of psychosocial, genetic, and medical causes of disease. Treatment strategies must take into account the coadministration of antiretroviral therapy and the specific neurologic problems common in patients infected with HIV.

PTSD co-morbid with HIV: Separate but equal, or two parts of a whole?

Approximately 30 million people currently live with HIV worldwide and the incidence of stress-related disorders, such as post-traumatic stress disorder (PTSD), is elevated among people living with HIV as compared to those living without the virus. PTSD is a severely debilitating, stress-related psychiatric illness associated with trauma exposure. Patients with PTSD experience intrusive and fearful memories as well as flashbacks and nightmares of the traumatic event(s) for much of their lives, may avoid other people, and may be constantly on guard for new negative experiences. This review will delineate the information available to date regarding the comorbidity of PTSD and HIV and discuss the biological mechanisms which may contribute to the co-existence, and potential interaction of, these two disorders. Both HIV and PTSD are linked to altered neurobiology within areas of the brain involved in the startle response and altered function of the hypothalamic-pituitary-adrenal axis. Collectively, the data highlighted suggest that PTSD and HIV are more likely to actively interact than to simply co-exist within the same individual. Multi-faceted interactions between PTSD and HIV have the potential to alter response to treatment for either independent disorder. Therefore, it is of great importance to advance the understanding of the neurobiological substrates that are altered in comorbid PTSD and HIV such that the most efficacious treatments can be administered to improve both mental and physical health and reduce the spread of HIV.

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.

Alexithymia, Assertiveness and Psychosocial Functioning in HIV: Implications for Medication Adherence and Disease Severity

Psychosocial function and adherence to antiretroviral regimen are key factors in human immunodeficiency virus (HIV) disease management. Alexithymia (AL) is a trait deficit in the ability to identify and describe feelings, emotions and bodily sensations. A structural equation model was used to test whether high levels of AL indirectly relate to greater non-adherent behavior and HIV disease severity via psychosocial dysfunction. Blood draws for HIV-1 viral load and CD4 T-lymphocyte, along with psychosocial surveys were collected from 439 HIV positive adults aged 18-73 years. The structural model supports significant paths from: (1) AL to non-active patient involvement, psychological distress, and lower social support, (2) psychological distress and non-active involvement to non-adherent behavior, and (3) non-adherence to greater HIV disease severity (CFI = .97, RMSEA = .04, SRMR = .05). A second model confirmed the intermediary effect of greater patient assertiveness on the path from AL to social support and non-active patient involvement (CFI = .94, RMSEA = .04, SRMR = .05). Altogether, AL is indirectly linked with HIV disease management through it's association with poor psychosocial function, however greater patient assertiveness buffers the negative impact of AL on relationship quality with healthcare providers and members of one's social support network.