Unravelling the triad of neuroinvasion, neurodissemination, and neuroinflammation of human immunodeficiency virus type 1 in the central nervous system.

Since the identification of human immunodeficiency virus type 1 (HIV-1) in 1983, many improvements have been made to control viral replication in the peripheral blood and to treat opportunistic infections. This has increased life expectancy but also the incidence of age-related central nervous system (CNS) disorders and HIV-associated neurodegeneration/neurocognitive impairment and depression collectively referred to as HIV-associated neurocognitive disorders (HAND). HAND encompasses a spectrum of different clinical presentations ranging from milder forms such as asymptomatic neurocognitive impairment or mild neurocognitive disorder to a severe HIV-associated dementia (HAD). Although control of viral replication and suppression of plasma viral load with combination antiretroviral therapy has reduced the incidence of HAD, it has not reversed milder forms of HAND. The objective of this review, is to describe the mechanisms by which HIV-1 invades and disseminates in the CNS, a crucial event leading to HAND. The review will present the evidence that underlies the relationship between HIV infection and HAND. Additionally, recent findings explaining the role of neuroinflammation in the pathogenesis of HAND will be discussed, along with prospects for treatment and control.

Neurocognitive Disorders in HIV-positive Patients.

Human immunodeficiency viruses (HIV) associated neurocognitive disorders (HAND) encompasses a group of syndromes of various degrees of impairment in cognition and daily functioning of HIV positive individuals. Although the widespread use of highly active antiretroviral therapy (HAART) has drastically reduced the prevalence of severe form of HAND, like HIV associated dementia (HAD), the prevalence of HAND and associated morbidity remains high. OBJECTIVES: (1) To know the prevalence of HAND in HIV-infected patients of a multi-ethnic population. (2) To describe various types of neurocognitive impairment among patients of HAND and study the factors affecting HAND. STUDY DESIGN: This study was a cross-sectional descriptive study conducted on 250 HIV-positive patients in outpatient department (OPD) of a tertiary care center in Mumbai, conducted over a period of 12 months. Patients with HIV-1 attending the OPD and having a minimal formal education of 4 years were included. Patients with concomitant delirium, any known central nervous system (CNS) disorder, any psychiatric disorder, and pregnant females were excluded. Outcome measures-the test batteries used were (1) International HIV Dementia Scale (IHDS) and (2) Addenbrookes cognitive examination-revised (ACE-R) scale. RESULTS: Of 250 subjects studied, 55.6% (139) were males and 44.4 % (111) were females. The mean age of study population was 39.42 years. The mean years of education were 8.32 years. The mean duration of infection (diagnosis of HIV-positive state) was 64.49 months and the mean duration of HAART intake in our patients was 52.30 months. The mean cluster of differentiation 4 (CD4) counts of our subjects were 527.13 per cumm [standard deviation (SD) of 234.13]. The mean nadir CD4 counts were 224.35 per cumm (SD of 115.09). Using the ACE-R scale, the prevalence of HAND was 71.60%, of which 37.20% had an asymptomatic neurological impairment, 29.60% had mild cognitive dysfunction, and 4.80% had HAD. Memory, verbal fluency and visuospatial abilities were the most affected domains on the ACE-R and memory recall and psychomotor speed were affected more on the IHDS. The prevalence of HAND was more with increasing age (p = 0.020), lesser education (p < 0.00) and lesser nadir CD4 counts (p < 0.00). However, it was not affected by the duration of the disease and the current CD4 counts (p > 0.05). CONCLUSION: Human immunodeficiency viruses (HIV) associated neurocognitive disorders HAND is common in HIV-positive patients, most of whom are asymptomatic. Older patients with less education and severe disease, having lower nadir counts are at the highest risk of HAND. Memory, verbal fluency, and visuospatial abilities were the most commonly affected domains.

Prevalence and 1-year incidence of HIV-associated neurocognitive disorder (HAND) in adults aged ≥50 years attending standard HIV clinical care in Kilimanjaro, Tanzania.

OBJECTIVES: HIV-associated neurocognitive disorders (HANDs) are prevalent in older people living with HIV (PLWH) worldwide. HAND prevalence and incidence studies of the newly emergent population of combination antiretroviral therapy (cART)-treated older PLWH in sub-Saharan Africa are currently lacking. We aimed to estimate HAND prevalence and incidence using robust measures in stable, cART-treated older adults under long-term follow-up in Tanzania and report cognitive comorbidities. DESIGN: Longitudinal study. PARTICIPANTS: A systematic sample of consenting HIV-positive adults aged ≥50 years attending routine clinical care at an HIV Care and Treatment Centre during March-May 2016 and followed up March-May 2017. MEASUREMENTS: HAND by consensus panel Frascati criteria based on detailed locally normed low-literacy neuropsychological battery, structured neuropsychiatric clinical assessment, and collateral history. Demographic and etiological factors by self-report and clinical records. RESULTS: In this cohort (n = 253, 72.3% female, median age 57), HAND prevalence was 47.0% (95% CI 40.9-53.2, n = 119) despite well-managed HIV disease (Mn CD4 516 (98-1719), 95.5% on cART). Of these, 64 (25.3%) were asymptomatic neurocognitive impairment, 46 (18.2%) mild neurocognitive disorder, and 9 (3.6%) HIV-associated dementia. One-year incidence was high (37.2%, 95% CI 25.9 to 51.8), but some reversibility (17.6%, 95% CI 10.0-28.6 n = 16) was observed. CONCLUSIONS: HAND appear highly prevalent in older PLWH in this setting, where demographic profile differs markedly to high-income cohorts, and comorbidities are frequent. Incidence and reversibility also appear high. Future studies should focus on etiologies and potentially reversible factors in this setting.

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

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

Biotypes of HIV-associated neurocognitive disorders based on viral and immune pathogenesis.

PURPOSE OF REVIEW: HIV-associated neurocognitive disorders (HAND) continues to be prevalent in people living with HIV despite antiretroviral therapy. However, understanding disease mechanisms and identifying therapeutic avenues has been challenging. One of the challenges is that HAND is a heterogeneous disease and that patients identified with similar impairments phenotypically may have very different underlying disease processes. As the NeuroAIDS field is re-evaluating the approaches used to identify patients with HIV-associated neurological impairments, we propose the subtyping of patients into biotypes based on viral and immune pathogenesis. RECENT FINDINGS: Here we review the evidence supporting subtyping patients with HIV-associated neurological complications into four biotypes: macrophage-mediated HIV encephalitis, CNS viral escape, T-cell-mediated HIV encephalitis, and HIV protein-associated encephalopathy. SUMMARY: Subtyping patients into subgroups based on biotypes has emerged as a useful approach for studying heterogeneous diseases. Understanding biotypes of HIV-associated neurocognitive impairments may therefore enable better understanding of disease mechanisms, allow for the development of prognostic and diagnostic markers, and could ultimately guide therapeutic decisions.

HIV-Associated Neurocognitive Disorders: The First Longitudinal Follow-Up of a cART-Treated Cohort of Older People in Sub-Saharan Africa.

BACKGROUND: HIV-associated neurocognitive disorders (HAND) are a highly prevalent chronic complication in older people living with HIV (PLWH) in high-income countries. Although sub-Saharan Africa has a newly emergent population of older combination antiretroviral therapy (cART)-treated PLWH, HAND have not been studied longitudinally. We assessed longitudinal prevalence of HAND and have identified possible modifiable factors in a population of PLWH aged 50 years or older, over 3 years of follow-up. METHODS: Detailed neuropsychological and clinical assessment was completed annually in the period 2016-2019 in a systematic sample of cART-treated PLWH in Kilimanjaro, Tanzania. A consensus panel defined HAND using American Academy of Neurology criteria for asymptomatic neurocognitive impairment, mild neurocognitive disorder, and HIV-associated dementia. HIV disease severity and other factors associated with HAND progression, improvement, and stability were evaluated in individuals fully assessed at baseline and in 2019. RESULTS: At baseline, 47% of the cohort (n = 253, 72.3% female individuals) met HAND criteria despite good HIV disease control [Y1 59.5% (n = 185), Y2 61.7% (n = 162), and Y3 57.9% (n = 121)]. Of participants fully assessed at baseline and year 3 (n = 121), HAND remained stable in 54% (n = 57), improved in 15% (n = 16), and declined in 31% (n = 33). Older age and lower education level significantly predicted HAND progression, whereas HIV-specific factors did not. Male sex and shorter cART duration were associated with improvement. CONCLUSIONS: In this first longitudinal study characterizing clinical course of HAND in older cART-treated PLWH in sub-Saharan Africa, HAND was highly prevalent with variable progression and reversibility. Progression may be more related to cognitive reserve than HIV disease in cART-treated PLWH.

Contemporary trends in HIV-associated neurocognitive disorders in Ghana.

BACKGROUND: Widespread introduction of early combination antiretroviral therapy (cART) for People Living with HIV (PLWH) will influence the burden, profile, and trajectory of HIV-associated neurocognitive disorders (HAND) in the 21st century. OBJECTIVES: To assess the prevalence and trajectory of HAND among PLWH in a Ghanaian tertiary medical center. METHODS: We analyzed the dataset of a study involving PLWH established on cART (n = 256) and PLWH not initially on cART (n = 244). HIV-negative individuals (n = 246) served as normative controls for neurocognitive assessments. HAND was defined according to the Frascati criteria into asymptomatic neurocognitive impairment (ANI), mild neurocognitive disorder (MND) and HIV-associated dementia (HAD) at enrollment and at month 12. Multivariate logistic regression models were fitted to identify factors associated with HAND. RESULTS: Among PLWH on cART, 21.5%, 3.5% and 0.0% had ANI, MND and HAD respectively compared with 20.1%, 9.8% and 2.0% among PLWH cART naïve, p < 0.0001. Overall, 71.6%, 20.8%, 6.6% and 1.0% had no cognitive impairment, ANI, MND and HAD at baseline. Among participants who completed month 12 follow-up, 55.2% had no cognitive impairment, 43.5%, 1.2%, 0.0% had ANI, MND and HAD respectively, p < 0.0001. Adjusted odds ratio (95% CI) of six independent predictors of HAND at month 12 were no education (3.29;1.81-6.00), stage 4 disease (4.64;1.37-15.69), hypertension (2.28;1.10-4.73), nevirapine use (2.05;1.04-4.05), baseline viral load (0.66;0.56-0.77), and cigarette use (0.10; 0.03-0.42). CONCLUSION: Most Ghanaian patients in the post-cART era with HAND had mild neurocognitive impairments. The impact of hypertension on progression of HAND warrants further evaluation in our settings.

Application of Data Mining Algorithms for Dementia in People with HIV/AIDS.

Dementia interferes with the individual's motor, behavioural, and intellectual functions, causing him to be unable to perform instrumental activities of daily living. This study is aimed at identifying the best performing algorithm and the most relevant characteristics to categorise individuals with HIV/AIDS at high risk of dementia from the application of data mining. Principal component analysis (PCA) algorithm was used and tested comparatively between the following machine learning algorithms: logistic regression, decision tree, neural network, KNN, and random forest. The database used for this study was built from the data collection of 270 individuals infected with HIV/AIDS and followed up at the outpatient clinic of a reference hospital for infectious and parasitic diseases in the State of Ceará, Brazil, from January to April 2019. Also, the performance of the algorithms was analysed for the 104 characteristics available in the database; then, with the reduction of dimensionality, there was an improvement in the quality of the machine learning algorithms and identified that during the tests, even losing about 30% of the variation. Besides, when considering only 23 characteristics, the precision of the algorithms was 86% in random forest, 56% logistic regression, 68% decision tree, 60% KNN, and 59% neural network. The random forest algorithm proved to be more effective than the others, obtaining 84% precision and 86% accuracy.

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

OBJECTIVES: Although the advent of Combination Antiretroviral Therapy (cART) has greatly reduced the prevalence of HIV-Associated Dementia, the most severe form of HIV-Associated Neurocognitive Disorder (HAND), the incidence of the milder forms of HAND have risen. The explanations proposed include persistent central nervous system (CNS) viraemia and the neurotoxicity of chronic cART regimens. Nonetheless, controversies in HAND prevalence estimates, alongside a lack of consensus on the significance of CNS Penetration Effectiveness (CPE) have added to the complexity of elucidating the role of cART in HAND. The present review will evaluate the evidence underlying these explanations, as well as highlighting the need for improved trial designs and the incorporation of emerging biomarkers and neuroimaging tools. METHODS: A review of the current literature investigating cART neurotoxicity, controversies in HAND prevalence estimates, CNS Penetration Effectiveness, and neuroprotective adjuvant therapies. CONCLUSIONS: Ultimately, the inadequacy of cART in achieving complete preservation of the CNS underscores the imminent need for neuroprotective adjuvant therapies, where the efficacy of combining multiple adjuvant classes presents a potential therapeutic frontier which must be interrogated.

Asymptomatic neurocognitive impairment is a risk for symptomatic decline over a 3-year study period.

OBJECTIVE: To examine whether persons with asymptomatic neurocognitive impairment (ANI) were more likely to show progression to mild neurocognitive disorder or HIV-associated dementia than those who were neuropsychologically normal (NP-N). DESIGN: Longitudinal observational cohort study. METHODS: Study sample included 720 HIV-1 seropositive persons (317 with ANI and 403 NP-N) receiving care in Toronto, Canada [83% were on antiretroviral treatment; 71% had undetectable (<50 copies/ml) plasma HIVRNA]. Neuropsychological assessments were conducted at 12 months intervals for a median follow-up time of 34 months. Neuropsychological data were corrected for age, education, sex, and race/ethnicity, and corrected for practice effect at follow-ups. Progression to mild neurocognitive disorder and HIV-associated dementia at each time point was determined using the Global Deficit Score and presence of cognitive symptoms. RESULTS: Over the follow-up period, 170 individuals (24%) progressed to symptomatic HIV-associated neurocognitive disorders (HAND). Persons with ANI were more likely to progress to symptomatic HAND than persons with NP-N after adjusting for baseline and time-varying confounders (adjusted hazards ratio: 1.88; 95% confidence interval: 1.37-2.60; P < 0.001). Female sex, depression, and cigarette smoking were associated with higher risk of progression to symptomatic HAND, but traditional HIV markers and antiretroviral treatment were not. CONCLUSION: ANI is associated with a two-fold increased risk of progression to symptomatic HAND in a cohort with universal healthcare access. This represents the largest replication of comparable US results. Reproducibility of these findings indicate that routine monitoring of persons with ANI and exploration of clinical interventions to prevent or delay progression to symptomatic HAND are imperative. SEARCH TERMS: HIV, HAND, HIV-associated dementia, cohort study, replicability, reproducibility.

Prevalence of HIV-associated neurocognitive disorder (HAND) in Turkey and assessment of Addenbrooke's Cognitive Examination Revised (ACE-R) test as a screening tool.

OBJECTIVES: We aimed to assess the Addenbrooke's Cognitive Examination Revised (ACE-R) and three questions (3Qs, European Aids Clinical Society Guidelines) as potential screening tools for HIV-associated neurocognitive disorder (HAND). In addition, we tried to determine the prevalence and associated factors for HAND among people living with HIV (PLWH) in Turkey. METHODS: Persons living with HIV were enrolled from two teaching hospitals between March 2018 and September 2018. Participants underwent screening tools, a neuropsychological test battery (NTB) and an assessment of activities of daily living. HAND was diagnosed according to Frascati's criteria and applying the Global Deficit Score (GDS) approach. A receiver operating characteristic (ROC) curve analysis was performed to compare the predictive accuracy of ACE-R to that of the NP test battery. Factors associated with HAND were evaluated using multivariate logistic regression analysis. RESULTS: The study sample included 162 participants (94% male). The HAND prevalence was 45.7% [asymptomatic neurocognitive impairment (ANI), 37.7%; mild neurocognitive disorder (MND), 7.4%; HIV-associated dementia (HAD), 0.6%] according to the Frascati criteria and 31.5% (ANI, 25.9%; MND, 4.9%; HAD, 0.6%) using the GDS. In the ROC analysis, the ACE-R showed an area under the curve of 0.68 at a cut-off score of 89. The sensitivity, specificity and correct classification rate of screening tests for HAND diagnosis were as follows: ACE-R (62.2%, 67%, 64.8%) and 3Qs (10.8%, 88.6%, 53%). In multivariate analysis, only education level (adjusted odds ratio [aOR] = 0.84, 95% CI: 0.76-0.92, P ≤ 0.001) was an independent risk factor for HAND. CONCLUSIONS: HAND is a common comorbidity in PLWH in Turkey. The sensitivities and specificities of 3Qs and the ACE-R as screening tools are lower than desired.

The far-reaching HAND of cART: cART effects on astrocytes.

Following the introduction of combination antiretroviral therapy (cART), the morbidity and mortality from human immunodeficiency virus (HIV) infection has been drastically curtailed and HIV has now become a chronic manageable disease. Persons living with HIV (PLWH) are living longer and experiencing significant co-morbidities and conditions of aging. NeuroHIV, clinically defined as HIV-Associated Neurocognitive Disorders (HAND) and pathologically manifested by persistent inflammation in the CNS despite cART, is a significant co-morbid condition for PLWH. In the pre-cART era, HIV mediated much of the pathogenesis in the Central Nervous System (CNS); in the cART era, with low to undetectable viremia, other mechanisms may be contributing to persistent neuroinflammation. Emerging data point to the adverse effects at the cellular level of cART, independent of HIV. Astrocytes are the most abundant cells in the CNS, playing vital roles in maintaining CNS homeostasis (e.g. metabolic support to neurons, clearance of neurotransmitters, ion balance, modulation of synaptic functions and maintaining the structural integrity of the blood brain barrier (BBB). Therefore, any disruption of their function will have wide repercussions in the CNS. In this review, we will address current knowledge and gaps on the impact of antiretrovirals (ARVs) on astrocytes and physiologic consequences in the CNS. Understanding the status of this field, will provide a practical framework to elucidate the potential role of cART-mediated dysregulation of astrocytes in neuroHIV pathogenesis and inform therapeutic strategies that are "neuro-friendly". Graphical abstract CNS-penetrating cART have the potential to cause resting astrocytes to become activated into an A1 or neurotoxic phenotype. These cells can in turn secrete inflammatory cytokines that affect surrounding microglia macrophages, as well as neurotoxic factors that impact nearby neurons. In addition, impairment in the physiologic functions of astrocytes will result in altered BBB permeability and disrupted metabolic homeostasis. CNS=Central Nervous System; cART=combined antiretroviral therapy; BBB=blood brain barrier.

HIV-Associated Neurocognitive Disorder (HAND): Relative Risk Factors.

This chapter will address the issue of risk for HIV-associated neurocognitive disorder (HAND), focusing on HIV-associated dementia (HAD), among persons living with HIV in relationship to the risk for other dementias. Advances in effective antiretroviral therapy (ART) have led to an increase in the prevalence of older persons surviving with HIV - in addition to older persons who become infected by HIV later in life. Hence, HIV is no longer a disease of younger persons, and additional attention has been brought to bear against the plight of older persons living with HIV - not only as it pertains to treatment but also to prevention. The additional risk caused by aging among older persons living with HIV is complex to asses, and HIV infection is a research area that requires a robust approach to multiple other factors causing neurocognitive impairment with older age. The long-term and potentially neurotoxic exposure to ART and the deleterious consequences of chronic infection with HIV and its associated neuro-inflammation have been described for health. This aids in the understanding of dementia risk factors in this patient population, but the comorbidities (HIV- and non-HIV-associated) occurring among older persons living with HIV must also be addressed to properly assess the overall impact on dementia risk in this group. This need also warrants our examination of the risk factors for other dementias (and comorbid dementias) in persons living with HIV versus the general population through the assessment and quantification of modifiable and non-modifiable risk factors identified as major contributors toward dementia.

Screening for HIV-Associated Neurocognitive Disorders: Sensitivity and Specificity.

HIV-associated neurocognitive disorder (HAND) remains prevalent among people living with HIV (PLWH), especially the mild forms, even those with well-controlled HIV. Recommendations from the literature suggest routine and regular screening for HAND to detect it early and manage it effectively and adjust treatments, if warranted, when present. However, screening for HAND is not routinely done, as there are no current guidelines on when to screen and which test or tests to use. Furthermore, many of the available screening tools for HAND often cannot accurately detect the mild forms of HAND and require highly trained healthcare professionals to administer and score the tests, a requirement that is not feasible for those low- and middle-income countries with the highest HIV incidence and prevalence rates. The purpose of this chapter was to review recent research on screening tests to detect HAND and report on the strengths, limitations, and psychometric properties of those tests to detect HAND.

Is the use of the QPC cognitive complaints questionnaire relevant for the screening strategy of HIV-Associated neurocognitive disorders?

BACKGROUND: The screening strategy for HIV-Associated Neurocognitive Disorders (HAND) is challenging. The French Expert Report recommend the use of the Cognitive Complaints Questionnaire (QPC) and the Montreal Cognitive assessment. However, the QPC has never been studied in People Living with HIV (PLWH). This study aims to determine the degree of agreement between QPC and the presence of HAND according to Frascati criteria, established by a battery of neuropsychological tests. METHODS: Data from patients who performed both a QPC and a battery of neuropsychological tests over a six-month follow-up period were evaluated retrospectively. RESULTS: A total of 121 patients were selected, with a median age of 53.1 years old. Among participants, 92.6% had an undetectable plasma viral load, 49.6% had a nadir CD4 less than 200/mm3 and 23.1% had a CDC stage C. Median CD4 cell count was 686/mm3. Prevalence of HAND was 57%, including 28.9% of Asymptomatic Neurocognitive Impairment, 24.8% of Mild Neurocognitive Disorder and 3.3% of HIV-associated Dementia. This analyze shows no agreement between QPC and HIV-associated neurocognitive disorders (kappa = -0.007). CONCLUSIONS: The QPC is not relevant in the screening for HAND. Thus, it urges to develop a specific tool to assess cognitive complaints among PLWH.

Screening for HIV-Associated Neurocognitive Disorder (HAND) in Adults Aged 50 and Over Attending a Government HIV Clinic in Kilimanjaro, Tanzania. Comparison of the International HIV Dementia Scale (IHDS) and IDEA Six Item Dementia Screen.

Validated screening tools for HIV-associated neurocognitive disorders (HAND) are lacking for the newly emergent ageing population of people living with HIV (PLWH) in sub-Saharan Africa (SSA). We aimed to validate and compare diagnostic accuracy of two cognitive screening tools, the International HIV dementia scale (IHDS), and the Identification and Interventions for Dementia in Elderly Africans (IDEA) screen, for identification of HAND in older PLWH in Tanzania. A systematic sample of 253 PLWH aged ≥ 50 attending a Government clinic in Tanzania were screened with the IHDS and IDEA. HAND were diagnosed by consensus American Academy of Neurology (AAN) criteria based on detailed clinical neuropsychological assessment. Strict blinding was maintained between screening and clinical evaluation. Both tools had limited diagnostic accuracy for HAND (area under the receiver operating characteristic (AUROC) curve 0.639-0.667 IHDS, 0.647-0.713 IDEA), which was highly-prevalent (47.0%). Accurate HAND screening tools for older PLWH in SSA are needed.

RESUMEN: Faltan pruebas cognitivas válidas para los trastornos neurocognitivos asociados al VIH (según sus siglas en inglés, HIV-Associated Neurocognitive Disorder (HAND) en la población emergente de personas mayores que viven con el VIH en el África subsahariana. Nuestro objetivo era validar y comparar la precisión diagnóstica de dos pruebas cognitivas, la escala internacional de demencia por VIH (según sus siglas en ingles International HIV dementia scale (IHDS) y la prueba 'IDEA', para el cribado de trastornos neurocognitivos asociados al VIH (HAND) en personas mayores viviendo con VIH en Tanzania. Una muestra sistemática de 253 personas de ≥50 años que asistieron a una clínica gubernamental en Tanzania se examinó con el IHDS y la IDEA. HAND fueron diagnosticados por consenso según los criterios de la Academia Americana de Neurología (AAN) basados en una detallada evaluación neuropsicológica y clínica. Las fases de cribado y de evaluación clínica se realizaron de forma independiente y a ciegas. Ambas herramientas tenían una precisión de diagnóstico limitada para HAND (área bajo la característica de funcionamiento del receptor (AUROC) curva 0.639 ­ 0.667 IHDS, 0.647-0.713 IDEA). HAND era altamente frecuente (47%). Se necesitan pruebas cognitivas por cribado de deterioro cognitivo en personas mayores con VIH en el África subsahariana.

Psycho-behavioral factors associated with neurocognitive performance among people living with HIV on antiretroviral therapy in Accra, Ghana.

BACKGROUND: It is estimated that almost half of all people living with HIV have some form of neurocognitive impairment, but few studies have looked at the risk of neurocognitive impairment and its associated factors in Ghana, due in part to limited resources for such testing. OBJECTIVES: To examine neurocognitive performance in a group of Ghanaians living with HIV and possible factors that contribute to their performance. METHODS: One hundred and four patients were assessed using a selection of brief non-invasive neuropsychological assessments as well as the International HIV Dementia Scale. Psycho-behavioural factors (alcohol use, depression, and medication adherence) as well as demographic characteristics and functional daily activities were assessed to determine their association with neurocognitive performance, using linear regression and receiver operating characteristic analyses. RESULT: About 48% of the participants met the criteria for risk of neurocognitive impairment. Age, education, and symptoms of depression were found to be significantly associated with the risk of impairment. CONCLUSION: Some people living with HIV showed risk of neurocognitive impairment, which was significantly associated with education, age and depressive symptoms. It is therefore important to consider routine neurocognitive screening in HIV management to recognize any risks for early interventions.

Unraveling neuroHIV in the Presence of Substance Use Disorders.

This special issue contains 10 invited review papers that highlighted and extended the presentations at the NIDA-sponsored workshop "Unraveling NeuroAIDS in the Presence of Substance Use Disorders" at the 25th Society on NeuroImmune Pharmacology conference in 2019. The topics covered by these papers focused on the interactive, additive or synergistic effects of substance use disorders (SUD) with HIV infection on the immune system and on neuropathogenesis. These papers reviewed four categories of substances of abuse (opioids, tobacco, stimulants, and cannabis) and how comorbid HIV infection (including models with HIV proteins, HIV transgenic rodent models and SIV) might further impact the dysregulated dopaminergic and immune systems, and the subsequent neuropathogenesis and behavioral disorders known as HIV-associated neurological disorders (HAND). These reviews provided detailed background knowledge regarding how each of these addictive substances and HIV individually or collectively affected the immune system at the cellular, molecular and system levels, and the subsequent clinical and behavioral outcomes. The authors also identified gaps, confounds or constraints in the current disease models and approaches, and proposed future research directions.

Global prevalence and burden of HIV-associated neurocognitive disorder: A meta-analysis.

OBJECTIVE: To characterize the prevalence and burden of HIV-associated neurocognitive disorder (HAND) and assess associated factors in the global population with HIV. METHODS: We searched PubMed and Embase for cross-sectional or cohort studies reporting the prevalence of HAND or its subtypes in HIV-infected adult populations from January 1, 1996, to May 15, 2020, without language restrictions. Two reviewers independently undertook the study selection, data extraction, and quality assessment. We estimated pooled prevalence of HAND by a random effects model and evaluated its overall burden worldwide. RESULTS: Of 5,588 records identified, we included 123 studies involving 35,513 participants from 32 countries. The overall prevalence of HAND was 42.6% (95% confidence interval [CI] 39.7-45.5) and did not differ with respect to diagnostic criteria used. The prevalence of asymptomatic neurocognitive impairment, mild neurocognitive disorder, and HIV-associated dementia were 23.5% (20.3-26.8), 13.3% (10.6-16.3), and 5.0% (3.5-6.8) according to the Frascati criteria, respectively. The prevalence of HAND was significantly associated with the level of CD4 nadir, with a prevalence of HAND higher in low CD4 nadir groups (mean/median CD4 nadir <200 45.2% [40.5-49.9]) vs the high CD4 nadir group (mean/median CD4 nadir ≥200 37.1% [32.7-41.7]). Worldwide, we estimated that there were roughly 16,145,400 (95% CI 15,046,300-17,244,500) cases of HAND in HIV-infected adults, with 72% in sub-Saharan Africa (11,571,200 cases, 95% CI 9,600,000-13,568,000). CONCLUSIONS: Our findings suggest that people living with HIV have a high burden of HAND in the antiretroviral therapy (ART) era, especially in sub-Saharan Africa and Latin America. Earlier initiation of ART and sustained adherence to maintain a high-level CD4 cell count and prevent severe immunosuppression is likely to reduce the prevalence and severity of HAND.

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.