The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study: baseline participant profile

Self-reported neurocognitive complaints in the Swiss HIV Cohort Study: a viral genome-wide association study

People with HIV may report neurocognitive complaints, with or without associated neurocognitive impairment, varying between individuals and populations. While the HIV genome could play a major role, large systematic viral genome-wide screens to date are lacking. The Swiss HIV Cohort Study biannually enquires neurocognitive complaints. We quantified broad-sense heritability estimates using partial 'pol' sequences from the Swiss HIV Cohort Study resistance database and performed a viral near full-length genome-wide association study for the longitudinal area under the curve of neurocognitive complaints. We performed all analysis (i) restricted to HIV Subtype B and (ii) including all HIV subtypes. From 8547 people with HIV with neurocognitive complaints, we obtained 6966 partial 'pol' sequences and 2334 near full-length HIV sequences. Broad-sense heritability estimates for presence of memory loss complaints ranged between 1% and 17% (Subtype B restricted 1-22%) and increased with the stringency of the phylogenetic distance thresholds. The genome-wide association study revealed one amino acid (Env L641E), after adjusting for multiple testing, positively associated with memory loss complaints (P = 4.3 * 10-6). Other identified mutations, while insignificant after adjusting for multiple testing, were reported in other smaller studies (Tat T64N, Env *291S). We present the first HIV genome-wide association study analysis of neurocognitive complaints and report a first estimate for the heritability of neurocognitive complaints through HIV. Moreover, we could identify one mutation significantly associated with the presence of memory loss complaints. Our findings indicate that neurocognitive complaints are polygenetic and highlight advantages of a whole genome approach for pathogenicity determination.

A high-throughput screening assay for silencing established HIV-1 macrophage infection identifies nucleoside analogs that perturb H3K9me3 on proviral genomes

HIV-infected macrophages are long-lived cells that represent a barrier to functional cure. Additionally, low-level viral expression by central nervous system (CNS) macrophages contributes to neurocognitive deficits that develop despite antiretroviral therapy (ART). We recently identified H3K9me3 as an atypical epigenetic mark associated with chronic HIV infection in macrophages. Thus, strategies are needed to suppress HIV-1 expression in macrophages, but the unique myeloid environment and the responsible macrophage/CNS-tropic strains require cell/strain-specific approaches. Here, we generated an HIV-1 reporter virus from a CNS-derived strain with intact auxiliary genes expressing destabilized luciferase. We employed this reporter virus in polyclonal infection of primary human monocyte-derived macrophages (MDM) for a high-throughput screen (HTS) to identify compounds that suppress virus expression from established macrophage infection. Screening ~6,000 known drugs and compounds yielded 214 hits. A secondary screen with 10-dose titration identified 24 meeting criteria for HIV-selective activity. Using three replication-competent CNS-derived macrophage-tropic HIV-1 isolates and viral gene expression readout in MDM, we confirmed the effect of three purine analogs, nelarabine, fludarabine, and entecavir, showing the suppression of HIV-1 expression from established macrophage infection. Nelarabine inhibited the formation of H3K9me3 on HIV genomes in macrophages. Thus, this novel HTS assay can identify suppressors of HIV-1 transcription in established macrophage infection, such as nucleoside analogs and HDAC inhibitors, which may be linked to H3K9me3 modification. This screen may be useful to identify new metabolic and epigenetic agents that ameliorate HIV-driven neuroinflammation in people on ART or prevent viral recrudescence from macrophage reservoirs in strategies to achieve ART-free remission. IMPORTANCE Macrophages infected by HIV-1 are a long-lived reservoir and a barrier in current efforts to achieve HIV cure and also contribute to neurocognitive complications in people despite antiretroviral therapy (ART). Silencing HIV expression in these cells would be of great value, but the regulation of HIV-1 in macrophages differs from T cells. We developed a novel high-throughput screen for compounds that can silence established infection of primary macrophages, and identified agents that downregulate virus expression and alter provirus epigenetic profiles. The significance of this assay is the potential to identify new drugs that act in the unique macrophage environment on relevant viral strains, which may contribute to adjunctive treatment for HIV-associated neurocognitive disorders and/or prevent viral rebound in efforts to achieve ART-free remission or cure.

Single nucleotide polymorphisms in aquaporin-4 associate with cognitive impairment status in people with HIV

Neurocognitive impairments are more frequent in people with HIV (PWH) compared to their uninfected counterparts. HIV-associated neurocognitive disorder (HAND) is a spectrum disorder and up to 50% of PWH are reported to suffer from HAND. Altered waste clearance from the brain, chronic neuroinflammation and impaired metabolic processes may contribute to abnormal aging in PWH and are more common among those who suffer from HAND. Thus, it is important to identify earlier predictors for development of HAND. A key contributor to cognitive impairment in HIV and in Alzheimer's disease (AD) is formation and accumulation of aberrant proteins including hyperphosphorylated Tau (pTau). Previous data from AD and traumatic brain injury studies report that impaired waste clearance from the brain contributes in part to cognitive impairments. Evidence suggests that the aquaporin 4 (aqp4) gene may have an important role in waste clearance from the brain as single nucleotide polymorphisms (SNPs) in aqp4 have been reported to associate with changes in cognitive decline in AD patients. Given some similarities between HAND and AD, we assessed potential associations of several aqp4 SNPS with cognitive impairment in PWH. Our data show that homozygous carriers of the minor allele in SNPs rs3875089 and rs3763040 had significantly lower neuropsychological test Z-scores in multiple domains compared to the other genotypes. Interestingly, this decrease in Z-scores was only observed in PWH and not in HIV-control participants. Conversely, homozygosity of the minor allele of rs335929 associated with better executive function in PWH. Based on these data, tracking large cohorts of PWH to determine if the presence of these SNPs associate with cognitive changes during disease progression is of interest. Furthermore, screening PWH for SNPs that may be associated with cognitive impairment risk after diagnosis could be considered in alignment with traditional treatment plans to potentially work on skills in areas shown to have cognitive decline with these SNPs present.

One for all, all for one: neuro-HIV multidisciplinary platform for the assessment and management of neurocognitive complaints in people living with HIV

BACKGROUND

With ageing, comorbidities such as neurocognitive impairment increase among people living with HIV (PLWH). However, addressing its multifactorial nature is time-consuming and logistically demanding. We developed a neuro-HIV clinic able to assess these complaints in 8 h using a multidisciplinary approach.

METHODS

People living with HIV with neurocognitive complaints were referred from outpatient clinics to Lausanne University Hospital. Over 8 h participants underwent formal infectious disease, neurological, neuropsychological and psychiatric evaluations, with opt-out magnetic resonance imaging (MRI) and lumbar puncture. A multidisciplinary panel discussion was performed afterwards, with a final report weighing all findings being produced.

RESULTS

Between 2011 and 2019, a total of 185 PLWH (median age 54 years) were evaluated. Of these, 37 (27%) had HIV-associated neurocognitive impairment, but they were mainly asymptomatic (24/37, 64.9%). Most participants had non-HIV-associated neurocognitive impairment (NHNCI), and depression was prevalent across all participants (102/185, 79.5%). Executive function was the principal neurocognitive domain affected among both groups (75.5% and 83.8% of participants impaired, respectively). Polyneuropathy was found in 29 (15.7%) participants. Abnormalities in MRI were found in 45/167 participants (26.9%), being more common among NHNCI (35, 77.8%), and HIV-1 RNA viral escape was detected in 16/142 participants (11.2%). Plasma HIV-RNA was detectable in 18.4% out of 185 participants.

CONCLUSIONS

Cognitive complaints remain an important problem among PLWH. Individual assessment from a general practitioner or HIV specialist is not enough. Our observations show the many layers of HIV management and suggest that a multidisciplinary approach could be helpful in determining non-HIV causes of NCI. A 1-day evaluation system is beneficial for both participants and referring physicians.

Anticholinergic and sedative medications are associated with neurocognitive performance of well-treated people living with HIV

Background

We previously showed that anticholinergic (ACH) medications contribute to self-reported neurocognitive impairment (NCI) in elderly people with human immunodeficiency virus (PWH). The current cross-sectional study further evaluated the effect of ACH and sedative drugs on neurocognitive function in PWH who underwent comprehensive neuropsychological evaluation.

Methods

A medication review was performed in PWH enrolled in the prospective Neurocognitive Assessment in Metabolic and Aging Cohort within the Swiss HIV Cohort Study. Neurocognitive functions were analyzed in 5 domains (motor skills, speed of information, attention/working memory, executive functions, and verbal learning memory). The effect of ACH and sedative medications on neurocognitive functioning was evaluated using linear regression models for the continuous (mean z-score) outcome and multivariable logistic regression models for the binary (presence/absence) outcome.

Results

A total of 963 PWH (80% male, 92% Caucasian, 96% virologically suppressed, median age 52) were included. Fourteen percent of participants were prescribed ≥1 ACH medication and 9% were prescribed ≥1 sedative medication. Overall, 40% of participants had NCI. Sedative medication use was associated with impaired attention/verbal learning and ACH medication use with motor skills deficits both in the continuous (mean z-score difference −0.26 to −0.14, P < .001 and P = .06) and binary (odds ratio [OR], ≥1.67; P < .05) models. Their combined use was associated with deficits in overall neurocognitive functions in both models (mean z-score difference −0.12, P = .002 and OR = 1.54, P = .03). These associations were unchanged in a subgroup analysis of participants without depression (n = 824).

Conclusions

Anticholinergic and sedative medications contribute to NCI. Clinicians need to consider these drugs when assessing NCI in PWH.

Declining Prevalence of Human Immunodeficiency Virus (HIV)-Associated Neurocognitive Disorders in Recent Years and Associated Factors in a Large Cohort of Antiretroviral Therapy-Treated Individuals With HIV

BACKGROUND

HIV-associated neurocognitive disorders (HAND) have been suggested as persistent even with effective antiretroviral therapy (ART). Aims were to evaluate HAND prevalence and associated factors, in a large cohort of people-with-HIV (PWH).

METHODS

ART-treated PWH, underwent a neuropsychological examination through a battery of 12 tests exploring 5 different domains, between 2009 and 2020, were included in this cross-sectional analysis. HAND were classified according to Frascati's criteria. Participants were defined as complaining or not-complaining if a cognitive complaint was reported or not. Chi-square for trend and multivariable logistic regression were fitted.

RESULTS

Overall, 1424 PWH were enrolled during four three-years periods. HAND prevalence was 24%; among complainers (572/1424), it was 38%, higher than among not-complainers (15%). Over the study period, a decreasing HAND prevalence was found in the entire population (P < 0.001) and in complaining (P < 0.001); in not-complaining it remained stable (P = 0.182). Factors associated with HAND were older age, lower educational level, lower current CD4+ T-cell count and HCV co-infection. Compared to nonnucleoside reverse transcriptase inhibitors, receiving dual and integrase strand transfer inhibitor (INSTI)-based therapies was associated with a decreased risk of HAND, as well as being tested in more recent years.

CONCLUSIONS

In this large cohort of ART-treated PWH, mostly virologically suppressed, a remarkable decreasing HAND prevalence was observed. Besides HIV- and patient-related factors, the reduced risk of HAND found with dual and INSTI-based regimens along with a more recent ART initiation, could suggest a potential role of new treatment strategies in this decline, due to their greater virologic efficacy and better tolerability.

Correlations between cerebrospinal fluid biomarkers, neurocognitive tests, and resting-state electroencephalography (rsEEG) in patients with HIV-associated neurocognitive disorders

HIV-associated neurocognitive disorders (HAND) are highly prevalent in people living with HIV (PLWH) despite successful treatment with combination antiretroviral therapy (cART). HAND pathogenesis is complex and definitive surrogate biomarkers are not clearly defined. Brain function has been assessed through the evaluation of cortical source rhythms with delta waves associated with neurological impairment. The aim of this study was to assess the correlation between EEG cortical sources, cerebrospinal fluid (CSF) biomarkers, and neurocognitive tests in PLWH with HAND. PLWH with HAND without significant comorbidities were enrolled. Baseline rsEEG-LORETA waves, CSF biomarkers (t-tau, p-tau, β-amiloid₄₂, neopterin, S100β), and neurocognitive tests were correlated and compared through non-parametric tests (Spearman's rho and Mann-Whitney); data are presented as medians (interquartile ranges). Fifty-four patients were enrolled. Median time of suppressed HIV-RNA and CD4⁺ T-lymphocyte were 10 years (5.5-15) and 691/uL (477-929). Thirty-nine participants (72%) underwent CSF collection: abnormal biomarkers were found in a small percentage. Only neopterin showed a statistically significant correlation with delta activity [parietal (rho 0.579; p < 0.001), occipital (rho 0.493; p = 0.007), and global sources (rho 0.464 p = 0.011)]. Seven patients (12.9%) showed an abnormal neopterin level (> 1.5 ng/mL) with significantly higher delta source activity compared to the ones with in-range concentrations. We observed a statistically significant correlation between working memory test Trail Making B with both CSF neopterin levels and delta waves (p values < 0.05). In a small sample of PLWH with HAND, we observed that higher CSF neopterin levels were associated with higher EEG delta waves and worse working memory tests.

Neurocognitive course at 2-year follow-up in a Swiss cohort of people with well-treated HIV

Objective:

The aim of this study was to examine neurocognitive course over time among people with well treated HIV.

Design:

The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study is an ongoing, prospective, longitudinal, multicenter and multilingual study within the Swiss HIV Cohort Study (SHCS). Participants undergo neuropsychological assessment at baseline and two-yearly follow-up.

Setting:

Seven SHCS centres.

Participants:

Patients aged at least 45 years enrolled in the SHCS with fluency in the local language (French, German or Italian) and agreeing to participate in the NAMACO study: 981 participants at baseline, 720 at 2-year follow-up of whom 644 had complete data sets.

Intervention:

Standardized neuropsychological assessment at baseline and 2-year follow-up.

Main outcome measure:

Neurocognitive performance using Frascati criteria and mean z-scores.

Results:

Four participants (of 644, 0.6%) had plasma HIV-1 RNA more than 50 copies/ml; median CD4⁺ cell count was 660 cells/μl. According to Frascati criteria, 204 participants (31.7%) had neurocognitive impairment (NCI) at baseline. NCI severity in these participants changed little over 2 years and comprehensive models based on Frascati criteria were not feasible. Examining mean z-scores, however, we observed neurocognitive stability or improvement over two years in five of seven neurocognitive domains assessed. Age at least 65 years (P = 0.02) and cognitive complaints (P = 0.004) were associated with neurocognitive decline, while black race (P = 0.01) and dolutegravir treatment (P = 0.002) were associated with improvement.

Conclusion:

Frascati criteria were less sensitive in measuring NCI change and therefore unsuitable for following neurocognitive course in our cohort of people with well treated HIV. Examining neurocognitive course by mean z-score change, we observed stability or improvement.

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.

Predicting occupational outcomes from neuropsychological test performance in older people with HIV

OBJECTIVE

The ability to work is amongst the top concerns of people living with well treated HIV. Cognitive impairment has been reported in many otherwise asymptomatic persons living with HIV and even mild impairment is associated with higher rates of occupational difficulties. There are several classification algorithms for HIV-associated neurocognitive disorder (HAND) as well as overall scoring methods available to summarize neuropsychological performance. We asked which method best explained work status and productivity.

DESIGN

Participants (N = 263) drawn from a longitudinal Canadian cohort underwent neuropsychological testing.

METHODS

: Several classification algorithms were applied to establish a HAND diagnosis and two summary measures (NPZ and Global Deficit Score) were computed. Self-reported work status and productivity was assessed at each study visit (four visits, 9 months apart). The association of work status with each diagnostic classification and summary measure was estimated using logistic regression. For those working, the value on the productivity scale was regressed within individuals over time, and the slopes were regressed on each neuropsychological outcome.

RESULTS

The application of different classification algorithms to the neuropsychological data resulted in rates of impairment that ranged from 28.5 to 78.7%. Being classified as impaired by any method was associated with a higher rate of unemployment. None of the diagnostic classifications or summary methods predicted productivity, at time of testing or over the following 36 months.

CONCLUSION

Neuropsychological diagnostic classifications and summary scores identified participants who were more likely to be unemployed, but none explained productivity. New methods of assessing cognition are required to inform optimal workforce engagement.

Clinical Utility of β-Amyloid PET Imaging in People Living With HIV With Cognitive Symptoms

BACKGROUND

Imaging with β-amyloid (Aβ) positron emission tomography (PET) has the potential to aid the diagnosis of the cause of cognitive impairment affecting people living with HIV (PLWH) when neurodegenerative disorders are considered. We evaluated the clinical utility of [18F]Florbetaben (FBB) in PLWH with cognitive symptoms.

METHODS

Imaging with FBB PET was performed in 20 patients with cognitive concerns about dementia. Neuropsychological testing, plasma neurofilament light protein, plasma Aβ40, Aβ42, and cerebrospinal fluid Aβ42, tau, and HIV RNA were obtained. FBB PET images were assessed visually by 3 readers blinded to the clinical diagnosis and quantitatively by obtaining a composite cortical to cerebellar cortex standardized uptake value ratio (SUVR). FBB SUVR from 10 age-matched healthy controls was compared with SUVR of PLWH.

RESULTS

Most participants were men (90%) of white ethnicity (90%) with a median age (interquartile range) of 59 (43-79) years. Median CD4 count was 682 (74-1056). All patients were on combination antiretroviral therapy with plasma and cerebrospinal fluid HIV RNA <40 copies/mL. Fourteen patients had objective cognitive impairment including 2 who met clinical criteria for a diagnosis of dementia. No significant differences in composite SUVRs between PLWH and controls [mean (SD): 1.18 (0.03) vs. 1.16 (0.09); P = 0.37] were observed. Four patients were FBB+ with the highest SUVR in the posterior cingulate, superior temporal, and frontal superior lobe. Amyloid PET results contributed to a change in diagnosis and treatment for 10 patients.

CONCLUSION

[18F]Florbetaben PET has potential as an adjunctive tool in the diagnosis of PLWH with cognitive impairment, increasing diagnostic certainty and optimizing management.

HIV Increases Sleep-based Brain Age Despite Antiretroviral Therapy

STUDY OBJECTIVES

Age-related comorbidities and immune activation raise concern for advanced brain aging in people living with HIV (PLWH). The brain age index (BAI) is a machine learning model that quantifies deviations in brain activity during sleep relative to healthy individuals of the same age. High BAI was previously found to be associated with neurological, psychiatric, cardiometabolic diseases, and reduced life expectancy among people without HIV. Here, we estimated the effect of HIV infection on BAI by comparing PLWH and HIV-controls.

METHODS

Clinical data and sleep EEGs from 43 PLWH on antiretroviral therapy (HIV+) and 3,155 controls (HIV-) were collected from Massachusetts General Hospital. The effect of HIV infection on BAI, and on individual EEG features, was estimated using causal inference.

RESULTS

The average effect of HIV on BAI was estimated to be +3.35 years (p < 0.01, 95% CI = [0.67, 5.92]) using doubly robust estimation. Compared to HIV- controls, HIV+ participants exhibited a reduction in delta band power during deep sleep and rapid eye movement sleep.

CONCLUSION

We provide causal evidence that HIV contributes to advanced brain aging reflected in sleep EEG. A better understanding is greatly needed of potential therapeutic targets to mitigate the effect of HIV on brain health, potentially including sleep disorders and cardiovascular disease.

Alcohol consumption and neurocognitive deficits in people with well-treated HIV in Switzerland

Background

Hazardous alcohol consumption and HIV infection increase the risk of neurocognitive impairment (NCI). We examined the association between alcohol consumption and specific neurocognitive domain function in people with HIV (PWH) taking modern antiretroviral therapy.

Methods

The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study is a prospective, longitudinal, multicentre and multilingual (French, German and Italian) study of patients aged ≥45 years old enrolled in the Swiss HIV Cohort Study (SHCS). Baseline data from 981 study participants were examined. Five neurocognitive domains were evaluated: motor skills, speed of information processing, attention/working memory, executive function and verbal episodic memory. NCI was examined as binary (presence/absence) and continuous (mean z-score) outcomes against Alcohol Use Disorders Identification Test for Consumption (AUDIT-C) scores using logistic and linear regression models, respectively.

Results

Most participants (96.2%) had undetectable viral loads and 64% were aged >50 years old. Hazardous alcohol consumption was observed in 49.4% of participants and binge drinking in 4.2%. While alcohol consumption frequency and quantity were not associated with NCI, the practice of binge drinking was significantly associated with impaired motor skills and overall neurocognitive function in both binary (odds ratio, OR ≥2.0, P <0.05) and continuous (mean z-score difference -0.2 to -0.4, P ≤0.01) outcomes. A significant U-shaped distribution of AUDIT-C score was also observed for motor skills and overall neurocognitive function.

Conclusions

In this cohort of PWH with well-controlled HIV infection, NCI was associated with the practice of binge drinking rather than alcohol consumption frequency or quantity. Longitudinal analysis of alcohol consumption and NCI in this population is currently underway.

The association between depressive symptoms and neurocognitive impairment in people with well-treated HIV in Switzerland

BACKGROUND

Depression may contribute to neurocognitive impairment (NCI) in people with HIV (PWH). Attributing NCI to depression rather than to HIV is complicated as depression may be both a causal factor and an effect of NCI. This study aimed to determine the association between depressive symptoms and NCI among PWH with well-controlled infection.

METHODS

The Neurocognitive Assessment in the Metabolic and Ageing Cohort study is an ongoing, prospective, longitudinal study of PWH aged ≥45 years old nested within the Swiss HIV Cohort Study. Neurocognitive Assessment in the Metabolic and Ageing Cohort study participants underwent neurocognitive assessment and grading of depressive symptoms using the Centre for Epidemiological Studies Depression Scale. Neurocognitive impairment categories were defined using Frascati criteria. Participants with NCI related to neurological or psychiatric confounders other than depression were excluded. The cross-sectional association between the Centre for Epidemiological Studies Depression score and neurocognitive impairment was examined taking Centre for Epidemiological Studies Depression score as a continuous variable and then as a binary variable using two score thresholds, 16 and 27.

RESULTS

Excluding 79 participants with confounding factors, 902 participants were studied: 81% were men; 96% had plasma viral loads <50 copies/ml; 35% had neurocognitive impairment; 28% had Centre for Epidemiological Studies Depression scores ≥16. Higher Centre for Epidemiological Studies Depression scores were associated with female sex (p = 0.0003), non-Caucasian origin (p = 0.011) and current/past intravenous drug use (p = 0.002). Whilst neurocognitive impairment was associated with higher Centre for Epidemiological Studies Depression scores, the Centre for Epidemiological Studies Depression score was a poor predictor of having neurocognitive impairment (area under the ROC curve 0.604). Applying a Centre for Epidemiological Studies Depression score threshold of 16 predicted the presence of neurocognitive impairment with a sensitivity of 38.3% (specificity 77.2%), increasing the threshold to 27 lowered sensitivity to 15.4% (specificity 93.6%).

CONCLUSION

In this large cohort of PWH in Switzerland, we did not observe a Centre for Epidemiological Studies Depression score threshold that was sensitive in predicting neurocognitive impairment. As neurocognitive impairment was however associated with higher Centre for Epidemiological Studies Depression scores, the data support the screening for and treatment of depression among PWH diagnosed with neurocognitive impairment.

Astrocytes, HIV and the Glymphatic System: A Disease of Disrupted Waste Management?

The discovery of the glial-lymphatic or glymphatic fluid clearance pathway in the rodent brain led researchers to search for a parallel system in humans and to question the implications of this pathway in neurodegenerative diseases. Magnetic resonance imaging studies revealed that several features of the glymphatic system may be present in humans. In both rodents and humans, this pathway promotes the exchange of interstitial fluid (ISF) and cerebrospinal fluid (CSF) through the arterial perivascular spaces into the brain parenchyma. This process is facilitated in part by aquaporin-4 (AQP4) water channels located primarily on astrocytic end feet that abut cerebral endothelial cells of the blood brain barrier. Decreased expression or mislocalization of AQP4 from astrocytic end feet results in decreased interstitial flow, thereby, promoting accumulation of extracellular waste products like hyperphosphorylated Tau (pTau). Accumulation of pTau is a neuropathological hallmark in Alzheimer's disease (AD) and is accompanied by mislocalization of APQ4 from astrocyte end feet to the cell body. HIV infection shares many neuropathological characteristics with AD. Similar to AD, HIV infection of the CNS contributes to abnormal aging with altered AQP4 localization, accumulation of pTau and chronic neuroinflammation. Up to 30% of people with HIV (PWH) suffer from HIV-associated neurocognitive disorders (HAND), and changes in AQP4 may be clinically important as a contributor to cognitive disturbances. In this review, we provide an overview and discussion of the potential contributions of NeuroHIV to glymphatic system functions by focusing on astrocytes and AQP4. Although HAND encompasses a wide range of neurocognitive impairments and levels of neuroinflammation vary among and within PWH, the potential contribution of disruption in AQP4 may be clinically important in some cases. In this review we discuss implications for possible AQP4 disruption on NeuroHIV disease trajectory and how HIV may influence AQP4 function.

A review of the potential mechanisms of neuronal toxicity associated with antiretroviral drugs

Highly active antiretroviral treatment has led to unprecedented efficacy and tolerability in people living with HIV. This effect was also observed in the central nervous system with the nowadays uncommon observation of dementias; yet in more recent works milder forms are still reported in 20-30% of optimally treated individuals. The idea of a subclinical neuronal toxicity induced by antiretrovirals has been proposed and was somehow supported by the late-emerging effects associated with efavirenz use. In this manuscript we are reviewing all the potential mechanisms by which antiretroviral drugs have been associated with in vitro, ex vivo, or in vivo toxicity to cells pertaining to the central nervous system (neurons, astrocytes, oligodendrocytes, and endothelial cells). These include direct or indirect effects and pathological pathways such as amyloid deposition, damage to small cerebral vessels, and impairment in neurotransmission. The aim of this review is therefore to provide a detailed description of the available literature in order to guide further clinical research for improving patients' neurocognition and quality of life.

How helpful are the European AIDS Clinical Society cognitive screening questions in predicting cognitive impairment in an aging, well-treated HIV-positive population?

Objectives

Diagnosing neurocognitive impairment (NCI) in HIV infection requires time‐consuming neuropsychological assessment. Screening tools are needed to identify when neuropsychological referral is indicated. We examined the positive and negative predictive values (PPVs and NPVs, respectively) of the three European AIDS Clinical Society (EACS) screening questions in identifying NCI.

Methods

The Neurocognitive Assessment in the Metabolic and Aging Cohort (NAMACO) study recruited patients aged ≥45 years enrolled in the Swiss HIV Cohort Study between 1 May 2013 and 30 November 2016. NAMACO participants (1) answered EACS screening questions, (2) underwent standardized neuropsychological assessment and (3) completed self‐report forms [Center for Epidemiologic Studies Depression Scale (CES‐D)] rating mood. NCI categories were defined using Frascati criteria. PPVs and NPVs of the EACS screening questions in identifying NCI categories were calculated.

Results

Of 974 NAMACO participants with complete EACS screening question data, 244 (25.1%) expressed cognitive complaints in answer to at least one EACS screening question, of whom 51.3% had NCI (26.1% HIV‐associated and 25.2% related to confounding factors). The PPV and NPV of the EACS screening questions in identifying HIV‐associated NCI were 0.35 and 0.7, respectively. Restricting analysis to NCI with functional impairment or related to confounding factors, notably depression, the NPV was 0.90. Expressing cognitive complaints for all three EACS screening questions was significantly associated with depression (P < 0.001).

Conclusions

The EACS screening questions had an NPV of 0.7 for excluding patients with HIV‐associated NCI as defined by Frascati criteria. The PPV and NPV may improve if NCI diagnoses are based on new criteria.