Elevation of cell-associated HIV-1 transcripts in CSF CD4+ T cells, despite effective antiretroviral therapy, is linked to brain injury.

Antiretroviral therapy (ART) can attain prolonged undetectable HIV-1 in plasma and cerebrospinal fluid (CSF), but brain injury remains prevalent in people living with HIV-1 infection (PLHIV). We investigated cell-associated (CA)-HIV-1 RNA transcripts in cells in CSF and blood, using the highly sensitive Double-R assay, together with proton Magnetic Resonance Spectroscopy (1H MRS) of major brain metabolites, in sixteen PLHIV. 14/16 CSF cell samples had quantifiable CA-HIV-1 RNA, at levels significantly higher than in their PBMCs (median 9,266 vs 185 copies /106 CD4+ T-cells; p<0.0001). In individual PLHIV, higher levels of HIV-1 transcripts in CSF cells were associated with greater brain injury in the frontal white matter (Std ß=-0.73; p=0.007) and posterior cingulate (Std ß=-0.61; p=0.03). 18-colour flow cytometry revealed that the CSF cells were 91% memory T-cells, equally CD4+ and CD8+ T-cells, but fewer B cells (0.4 %), and monocytes (3.1%). CXCR3+CD49d+integrin ß7-, CCR5+CD4+ T-cells were highly enriched in CSF, compared with PBMC (p <0.001). However, CA-HIV-1 RNA could not be detected in 10/16 preparations of highly purified monocytes from PBMC, and was extremely low in the other six. Our data show that elevated HIV-1 transcripts in CSF cells were associated with brain injury, despite suppressive ART. The cellular source is most likely memory CD4+ T cells from blood, rather than trafficking monocytes. Future research should focus on inhibitors of this transcription to reduce local production of potentially neurotoxic and inflammatory viral products.

HIV associated neurocognitive disorder screening and diagnosis pathways in Australia: a scoping review and international implications.

Symptomatic HIV-associated neurocognitive disorder (HAND) is a complication of HIV (cognitive impairment, difficulties with everyday functioning). If detected early, interventions assist with optimizing care, avoiding rapid decline and enhancing coping. There remains inconsistency surrounding screening/diagnosis information within Australian healthcare professionals and community settings. A scoping review of academic literature, government policies and non-government organisations (NGOs) was conducted to map existing screening/diagnosis information using the guidelines of Joanna Briggs Institute. A literature search of EBSCOhost and Medline (dates: 2015-2021), the Australian government NGO web domains, Google and unpublished academic works was conducted (July 2021) and updated (December 2022) to identify Australian items (past 5 years). Seventeen items met the inclusion criteria. No government guidelines were identified. Various HIV-related organisations proposed different diagnostic guidelines. Most HAND research originated in Sydney. The most accessible information was from Dementia Australia, with some inaccuracies noted. There is scant Australian research/information on HAND screening/diagnosis. HAND translational research and screening/diagnosis standards are urgently needed to inform best practices. The Australian context is used to discuss international implications regarding higher-income countries with similar patterns/healthcare.

The Evolution of Assessing Central Nervous System Complications in Human Immunodeficiency Virus: Where Do We Go From Here?

In this fifth decade of the human immunodeficiency virus (HIV) epidemic, central nervous system (CNS) complications including cognitive impairment and mental health remain a burden for people with HIV (PWH) on antiretroviral therapy. Despite the persistence of these complications, which often co-occur, the underlying pathophysiology remains elusive and consequently treatments remain limited. To continue to grow our understanding of the underlying mechanisms of CNS complications among PWH, there is a need to reexamine our current approaches, which are now more than 2 decades old. At the 2021 National Institutes of Health-sponsored meeting on Biotypes of CNS Complications in PWH, the Neurobehavioral Working Group addressed the following: (1) challenges inherent to determining CNS complications; (2) heterogeneity in CNS complications; and (3) problems and solutions for examining integrated biotypes. The review below provides a summary of the main points presented and discussed by the Neurobehavioral Working Group at the meeting.

Low incidence of advanced neurological burden but high incidence of age-related conditions that are dementia risk factors in aging people living with HIV: a data-linkage 10-year follow-up study.

Although increasing research is focusing on age-related comorbidities (ARC) among people living with HIV (PLHIV), no studies have concomitantly assessed non-HIV age-related neurological disorders (e.g., Alzheimer's dementia). A total of 254 PLHIV and 69 HIV-negative controls completed baseline medical history and cognitive testing. ARC data were collected from medical records over the subsequent 9-10 years and included all types of strokes, all types of dementia, mild cognitive impairment, Parkinson's disease, motor neuron disease (grouped into a non-HIV age-related neurological category), cardiovascular disease, chronic kidney disease, chronic liver disease, chronic lung disease, non-AIDS cancers, osteoporosis, and diabetes. Kaplan-Meier curves assessed differences in the incident rates (per 1000 person year) of groups of ARC as defined above and combined ARC (i.e., development of any of the ARC) among younger (baseline age < 50) and older (baseline age ≥ 50) PLHIV and younger and older controls. Cox-proportional hazard models assessed the individual and interaction effects of HIV status and chronological age, in addition to a range of demographic and clinical variables including historical and baseline HIV brain involvement on the risk of developing combined ARC. Older PLHIV had a higher incidence of cardiovascular disease, osteoporosis, and combined ARC compared to other groups (p < 0.05). Incident rate of non-HIV age-related neurological disorders was 2.3 [0.93, 4.79] per 1000 person year. While this incident rate was higher in older PLHIV (5.37 [1.97, 11.92]) than older HIV-negative participants (3.58 [0.18-17.67]), this was not significant. In multivariate analyses, HIV status and chronological age, but not their interaction, and smoking were associated with higher risk of combined ARC (p < 0.05). In analyses focusing on PLHIV, older age and taking abacavir/efavirenz/atazanavir/darunavir containing antiretroviral treatments at the time of diagnosis were associated with greater ARC (p < 0.05). Non-HIV age-related neurological disorders are uncommon in older PLHIV, where the majority were < 70 years of age at the end of follow-up. However, the greater burden of ARC among older PLHIV, most of which are established dementia risk factors, warrants the establishment of commensurate prevention strategies and greater attention to neurocognitive screening.

Psychosocial risk factors and cognitive decline in people living with HIV: results from the Malaysian HIV and aging (MHIVA) study.

HIV-associated mortality has improved with the advent of antiretroviral therapy, yet neurocognitive decline persists. We assessed the association between psychosocial risk factors and cognitive function among Malaysian PLWH. Data of virally suppressed PLWH (n = 331) on stable ART, from the Malaysian HIV and Aging study was assessed. Psychosocial factors were assessed using the Lubben Social Network Scale-6 (social isolation) and Depression Anxiety Stress Scale-21 (DASS-21). The Montreal Cognitive Assessment (MoCA) with normative standards for the Malaysian population was used to determine cognitive function. Linear and logistic regression were used to assess the associations between cognition, and psychosocial risk factors. Median age of participants was 43.8 years (IQR 37.7-51.0). Participants were predominantly male (82.8%), with secondary education or higher (85.2%). Participants were on ART for 5.7 years (IQR 3.0-9.7), with a mean MoCA score of 24.6 (±3.7). Social isolation was found in 34.6% of participants, and severe depression, severe stress, and severe anxiety in 10.6%, 15.4%, and 6.0% respectively. After adjusting for demographic, clinical, and HIV parameters, MoCA scores were significantly associated with severe stress (ß = -0.11, p = 0.02) and having marginal friendship ties (ß = -0.13, p = 0.03). Social isolation and severe stress are associated with neurocognitive impairment in PLWH.

Central Nervous System Manifestations of COVID-19: A Critical Review and Proposed Research Agenda.

OBJECTIVE: On March 11, 2020, the World Health Organization declared an outbreak of a new viral entity, coronavirus 2019 (COVID-19), to be a worldwide pandemic. The characteristics of this virus, as well as its short- and long-term implications, are not yet well understood. The objective of the current paper was to provide a critical review of the emerging literature on COVID-19 and its implications for neurological, neuropsychiatric, and cognitive functioning. METHOD: A critical review of recently published empirical research, case studies, and reviews pertaining to central nervous system (CNS) complications of COVID-19 was conducted by searching PubMed, PubMed Central, Google Scholar, and bioRxiv. RESULTS: After considering the available literature, areas thought to be most pertinent to clinical and research neuropsychologists, including CNS manifestations, neurologic symptoms/syndromes, neuroimaging, and potential long-term implications of COVID-19 infection, were reviewed. CONCLUSION: Once thought to be merely a respiratory virus, the scientific and medical communities have realized COVID-19 to have broader effects on renal, vascular, and neurological body systems. The question of cognitive deficits is not yet well studied, but neuropsychologists will undoubtedly play an important role in the years to come.

Assessment of Neurocognitive Functions, Olfaction, Taste, Mental, and Psychosocial Health in COVID-19 in Adults: Recommendations for Harmonization of Research and Implications for Clinical Practice.

OBJECTIVE: To propose a set of internationally harmonized procedures and methods for assessing neurocognitive functions, smell, taste, mental, and psychosocial health, and other factors in adults formally diagnosed with COVID-19 (confirmed as SARS-CoV-2 + WHO definition). METHODS: We formed an international and cross-disciplinary NeuroCOVID Neuropsychology Taskforce in April 2020. Seven criteria were used to guide the selection of the recommendations' methods and procedures: (i) Relevance to all COVID-19 illness stages and longitudinal study design; (ii) Standard, cross-culturally valid or widely available instruments; (iii) Coverage of both direct and indirect causes of COVID-19-associated neurological and psychiatric symptoms; (iv) Control of factors specifically pertinent to COVID-19 that may affect neuropsychological performance; (v) Flexibility of administration (telehealth, computerized, remote/online, face to face); (vi) Harmonization for facilitating international research; (vii) Ease of translation to clinical practice. RESULTS: The three proposed levels of harmonization include a screening strategy with telehealth option, a medium-size computerized assessment with an online/remote option, and a comprehensive evaluation with flexible administration. The context in which each harmonization level might be used is described. Issues of assessment timelines, guidance for home/remote assessment to support data fidelity and telehealth considerations, cross-cultural adequacy, norms, and impairment definitions are also described. CONCLUSIONS: The proposed recommendations provide rationale and methodological guidance for neuropsychological research studies and clinical assessment in adults with COVID-19. We expect that the use of the recommendations will facilitate data harmonization and global research. Research implementing the recommendations will be crucial to determine their acceptability, usability, and validity.

Lack of cognitive impairment in long-term survivors of colorectal cancer.

BACKGROUND: Our longitudinal study reported cognitive impairment in 43% of people following diagnosis of localised colorectal cancer (CRC) versus 15% in healthy controls (p < 0.001) and 50% versus 13% 1-2 years later (p < 0.001). Here we evaluate cognitive function and neuroimaging in a subgroup at long-term follow-up. PATIENTS AND METHODS: Cancer-free Australian participants in the study, and controls, completed cognitive and functional assessments. Neuroimaging was optional. Blood tests included inflammatory markers, clotting factors, sex hormones and apolipoprotein E genotype. The primary endpoint was demographically and practice effect-corrected cognitive scores comparing CRC survivors with controls over time examined using a linear mixed model, adjusted for baseline performance. Secondary endpoints included cognitive impairment rate using the Global Deficit Score [GDS > 0.5], Functional Deficit Score, blood results and neuroimaging. RESULTS: The study included 25 CRC survivors (60% men, median age 72) at mean 9 years after baseline (9 received adjuvant chemotherapy) and 25 controls (44% men, median age 68) at mean 6 years after baseline. There were no significant differences in cognitive scores or proportion with cognitive impairment (16 vs. 8%) between survivors and controls and no evidence of accelerated ageing in CRC survivors. Baseline cognitive performance predicted for subsequent cognitive function. There were no differences in functional tests or blood tests between groups. In 18 participants undergoing neuroimaging, 10 CRC survivors had higher myoinositol levels than 8 controls, and lower volume in the right amygdala and caudate and left hippocampal regions. CONCLUSIONS: There was no difference in cognitive capacity and function between CRC survivors and controls 6-12 years after diagnosis. Differences in neuroimaging require confirmation in a larger sample. HIGHLIGHTS: • No evidence of long term cognitive impairment in colorectal cancer survivors compared to controls 6-12 years after diagnosis • No evidence of accelerated cognitive ageing in colorectal cancer survivors • No evidence of long-term functional impairment in colorectal cancer survivors.

Is There Any Evidence of Premature, Accentuated and Accelerated Aging Effects on Neurocognition in People Living with HIV? A Systematic Review.

Despite evidence of premature, accentuated and accelerated aging for some age-related conditions such as cardiovascular diseases in people living with HIV (PLHIV), the evidence for these abnormal patterns of aging on neurocognition remains unclear. Further, no systematic review has been dedicated to this issue. Using PRISMA guidelines, we searched standard databases (PubMed, EMBASE, CINAHL and PsycINFO). Articles were included if they analyzed and reported the effect of age on neurocognition among PLHIV as one of their major findings, if they were conducted in the combination anti-retroviral therapy era (after 1996) and published in a peer-reviewed journal in English. Quality appraisal was conducted using the Joanna Briggs Institute (JBI) appraisal tools. To systematically target the abnormal patterns of neurocognitive aging, we define premature cognitive aging as significant interaction effect of HIV status and age on cross-sectional neurocognitive test performance covering both the normal and abnormal performance range; accentuated cognitive aging as significant interaction effect of HIV status and age on cross-sectional neurocognitive impairment (NCI) rate, thus covering the abnormal performance range only; accelerated cognitive aging as significant interaction effect of HIV status and age on longitudinal neurocognitive test performance or incidence of NCI. Because these definitions require an age-comparable HIV-negative (HIV-) control group, when no controls were included, we determined the range of the age effect on neurocognitive test performance or NCI among PLHIV. A total of 37 studies originating from the US (26), UK (2), Italy (2), Poland (2), China (2), Japan (1), Australia (1), and Brazil (1) were included. Six studies were longitudinal and 14 included HIV- controls. The quality appraisal showed that 12/37 studies neither used an age-matched HIV- controls nor used demographically corrected cognitive scores. A meta-analysis was not possible because study methods and choice of neurocognitive measurement methods and outcomes were heterogeneous imposing a narrative synthesis. In studies with an HIV- control sample, premature neurocognitive aging was found in 45% of the cross-sectional analyses (9/20), while accelerated neurocognitive aging was found in 75% of the longitudinal analyses (3/4). There was no evidence for accentuated aging, but this was tested only in two studies. In studies without an HIV- control sample, the age effect was always present but wide (NCI OR = 1.18-4.8). While large sample size (> 500) was associated with abnormal patterns of cognitive aging, most of the studies were under powered. Other study characteristics such as longitudinal study design and higher proportion of older participants were also associated with the findings of abnormal cognitive aging. There is some support for premature and accelerated cognitive aging among PLHIV in the existing literature especially among large and longitudinal studies and those with higher proportion of older samples. Future HIV and cognitive aging studies need to harmonize neuropsychological measurement methods and outcomes and use a large sample from collaborative multi-sites to generate more robust evidences.

Vascular cognitive impairment and HIV-associated neurocognitive disorder: a new paradigm.

In this review, we propose that vascular cognitive impairment (VCI), with relevance for the global HIV population, is fundamentally and clinically linked to the persistence of mild forms of HIV-associated neurocognitive disorders (HAND) in ageing people living with HIV infection (PLWH). After placing our review within the context of the general literature on HIV and ageing, we review non-VCI risks for dementia in ageing PLWH. We then present the recently updated VCI nomenclature and show that the neuropsychological and neuroimaging phenotypes of VCI and HAND are largely overlapping, suggesting that further research is needed to accurately distinguish them. We further link VCI and HAND at the mechanistic level by advancing the innovative proposal that the neuro-vascular unit (NVU) may represent the primary target of HIV-related brain injury in treated HIV infection. To this, we add the fundamental impact of mild and major VCI on the NVU. Importantly, we show that the potential contribution of vascular damage to overall brain damage in ageing PLWH is probably much higher than currently estimated because of methodological limitations, and because this research is only emerging. Finally, because all VCI risk factors are more prevalent, premature, and sometimes accelerated in the HIV population at large, we conclude that the probable total burden of VCI in the global HIV population is higher than in the general population and would need to be compared to chronic conditions such as type I diabetes and multiple sclerosis to account for the disease chronicity and lifelong treatment effects. Therefore, this review is also a call to action. Indeed, it is fully established that this amount of VCI burden is a major risk factor for dementia at aged 60+.

Utility of Using the Montreal Cognitive Assessment (MoCA) as a Screening Tool for HIV-Associated Neurocognitive Disorders (HAND) In Multi-Ethnic Malaysia.

This study determines the optimal cut-off scores for the Montreal Cognitive Assessment (MoCA) to detect HIV-associated neurocognitive disorders (HAND) in a multi-ethnic Malaysian HIV-positive cohort by developing demographically corrected normative standards among 283 HIV-negative community-based controls with overlapping demographic characteristics. The norms (corrected for age, sex, education, ethnicity) were applied to 342 HIV-positive virally suppressed individuals on cART. Impairment rates were classified using the Global Deficit Score (GDS ≥ .5) method. The MoCA was also scored according to the recommended cut-off of ≤ 26, and functional decline was applied to both impairment definitions to classify HAND per the Frascati criteria. The ≤ 26 cut-off considerably overestimated cognitive impairment in both samples (59.4% HIV-negative; 69.3% HIV-positive). In contrast, corrected scores yielded impairment rates consistent with what has been reported internationally in virally suppressed cohorts (23.4% with 83.3% mild impairment, 16.7% moderate impairment). A supplemental file allowing the computation of corrected MoCA scores and impairment status is included.

White matter measures are near normal in controlled HIV infection except in those with cognitive impairment and longer HIV duration.

The objective of the current study was to quantify the degree of white matter (WM) abnormalities in chronic and virally suppressed HIV-infected (HIV+) persons while carefully taking into account demographic and disease factors. Diffusion tensor imaging (DTI) was conducted in 40 HIV- and 82 HIV+ men with comparable demographics and life style factors. The HIV+ sample was clinically stable with successful viral control. Diffusion was measured across 32 non-colinear directions with a b-value of 1000 s/mm2; fractional anisotropy (FA) and mean diffusivity (MD) maps were quantified with Itrack IDL. Using the ENIGMA DTI protocol, FA and MD values were extracted for each participant and in 11 skeleton regions of interest (SROI) from standard labels in the JHU ICBM-81 atlas covering major striato-frontal and parietal tracks. We found no major differences in FA and MD values across the 11 SROI between study groups. Within the HIV+ sample, we found that a higher CNS penetrating antiretroviral treatment, higher current CD4+ T cell count, and immune recovery from the nadir CD4+ T cell count were associated with increased FA and decreased MD (p < 0.05-0.006), while HIV duration, symptomatic, and asymptomatic cognitive impairment were associated with decreased FA and increased MD (p < 0.01-0.004). Stability of HIV treatment and antiretroviral CNS penetration efficiency in addition to current and historical immune recovery were related to higher FA and lower MD (p = 0.04-p < 0.01). In conclusion, WM DTI measures are near normal except for patients with neurocognitive impairment and longer HIV disease duration.

Monitoring HIV-Associated Neurocognitive Disorder Using Screenings: a Critical Review Including Guidelines for Clinical and Research Use.

Screening tools to identify HIV-associated neurocognitive disorder (HAND) are primarily devised to detect cognitive impairment on a single occasion. With the chronicity of HIV infection and the risk of HAND developing or progressing despite viral control, it may be pertinent to repeat HAND screening at more than one time point. Despite this, there are limited data on longitudinal use of such screening tools, particularly with regard to the role of practice effects. Additionally, no guidelines currently exist on the timeframe between testing intervals, or recommendation of the magnitude of baseline impairment that warrants follow-up testing. The aim of the current paper was to review existing evidence for longitudinal validity of HAND screening tools. Only those HAND screening tools previously found to have high cross-sectional criterion validity were included. Preliminary recommendations for clinical use and future research are proposed including in international settings.

HIV-Associated Neurocognitive Disorders: A Global Perspective.

The present review on HIV-associated neurocognitive disorders (HAND) provides a worldwide overview of studies that have investigated the rate and neuropsychological (NP) profile of HAND research since the inception of the 2007 HAND diagnostic nomenclature. In the first part, the review highlights some of the current controversies around HAND prevalence rates. In the second part, the review critically assesses some solutions to move the field forward. In the third part, we present the cross-sectional NP profile in non-Western HIV+ cohorts and in relation to Western cohorts' findings. The adopted global perspective highlights the successful expansion of NP studies in HIV infection to culturally diverse low- to medium-income countries with high HIV burden. These studies have produced interestingly similar rates of HAND whether patients were naïve or treated and/or virally suppressed compared to the rich income countries where the NP research in NeuroHIV has originated. The perspective also demonstrates that globally, the group which is the most representative of the HIV epidemic, and thus at risk for HAND are persons with chronic HIV infection and survivors of past immunosuppression, while in relative terms, those who have been treated early with long-term viral suppression represent a minority. In the last part, we present a review of the naturalistic longitudinal NP global studies in HIV+cohorts, discuss the role of longitudinal design in solving issues around the question of asymptomatic neurocognitive impairment, and the question of biomarker discovery. Finally, we conclude by calling for greater methods and data harmonization at a global level. (JINS, 2017, 23, 860-869).

A Screening Strategy for HIV-Associated Neurocognitive Disorders That Accurately Identifies Patients Requiring Neurological Review.

BACKGROUND: Human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) are not routinely assessed due to the lack of an adequate screening strategy. We aimed to develop a clinically relevant screening procedure for symptomatic HAND, validated against a gold standard neuropsychological (NP) test battery. METHODS: Representative HIV-infected (HIV+) and demographically matched HIV-uninfected (HIV-) participants in an observational study completed a standard evaluation for mood, drug and/or alcohol use, and activities of daily living and a newly designed 20-minute computerized CogState battery that assessed 5 cognitive domains. A subset completed standard NP assessment for 8 cognitive domains. HAND definition on screening and gold standard NP was determined using demographically corrected z scores and the global deficit score (≥ 0.5), applying the Frascati criteria. Participants were blinded to screening results, and the NP examiner was blinded to screening and HIV status. RESULTS: A total of 254 HIV+ participants were enrolled-mean age, 48.9 ± 10.2 years; median nadir CD4, 270 cells/mL; tertiary educated, 54%; and HIV- controls, 72. HIV+ HAND screening prevalence was 30.7% (HIV-associated dementia, 3.2%; mild neurocognitive disorder, 12.6%; and asymptomatic neurocognitive disorder, 15.0%; HIV- group: 13.9%; P = .004). Of the 75 participants who completed the NP battery, the HAND rate in the HIV+ group was 50.9% vs 43.4% by screening (P > .50). HAND screening vs gold standard NP sensitivity was 76% and specificity was 71%. Clinically relevant HIV-associated dementia and mild neurocognitive disorder sensitivity was 100% and specificity was 98% (positive predictive value 0.92). CONCLUSIONS: Symptomatic HAND warranting neurological review was accurately predicted using a CogState-based screening procedure.

The role of depression chronicity and recurrence on neurocognitive dysfunctions in HIV-infected adults.

Research assessing whether major depressive disorders (MDD) impacts neurocognitive functions in HIV+ persons has yielded inconsistent results. However, none have considered the role of MDD remission, chronicity, and stability on treatment. Ninety-five HIV+ adults clinically stable on combined antiretroviral treatment completed a psychiatric interview, a depression scale, a neuropsychological, daily living, and cognitive complaints assessments at baseline and 18 months. Participants were screened for current (within 12 months of study entry) alcohol and/or substance use disorder. History of alcohol and/or substance abuse disorder prior to the 12 months entry screen and MDD treatments were recorded. Participants were grouped into two psychiatric nomenclatures: (1) lifetime: no MD episode (MDE), single MDE life-event treated and fully remitted, chronic MDD treated and stable, chronic MDD treated and unstable, and baseline untreated MDE; (2) recent: last 2 years MDE (yes or no). We found that lifetime and recent psychiatric history were more strongly associated with decreased in independence in daily living and cognitive complaints than with baseline neuropsychological performance. However, lack of full remission, instability on treatment in chronic MDD, and severity of symptoms in current MDE were factors in whether MDD impacted baseline neuropsychological performance. Depressive symptoms improved at follow-up in those with baseline moderate-severe symptoms, and MDD was not associated with neurocognitive change at 18 months. A history of alcohol and/or substance abuse disorder was significantly more frequent in those with treated and unstable chronic MDD but it was not associated with neuropsychological performance. MDD recurrence, chronicity profiles, and associated comorbidities are keys factors to understand any potential impact on neurocognitive abilities in HIV infection. More comprehensive consideration of these complex effects could serve at constructively updating the HAND diagnostic criteria.

APOE ε4 moderates abnormal CSF-abeta-42 levels, while neurocognitive impairment is associated with abnormal CSF tau levels in HIV+ individuals - a cross-sectional observational study.

BACKGROUND: Cerebrospinal fluid (CSF) biomarkers Aß1-42, t-tau and p-tau have a characteristic pattern in Alzheimer's Disease (AD). Their roles in HIV-associated neurocognitive disorder (HAND) remains unclear. METHODS: Adults with chronic treated HIV disease were recruited (n = 43, aged 56.7 ± 7.9; 32% aged 60+; median HIV duration 20 years, >95% plasma and CSF HIV RNA <50 cp/mL, on cART for a median 24 months). All underwent standard neuropsychological testing (61% had HAND), APOE genotyping (30.9% carried APOE ε4 and 7.1% were ε4 homozygotes) and a lumbar puncture. Concentrations of Aß1-42, t-tau and p-tau were assessed in the CSF using commercial ELISAs. Current neurocognitive status was defined using the continuous Global Deficit Score, which grades impairment in clinically relevant categories. History of HAND was recorded. Univariate correlations informed multivariate models, which were corrected for nadir CD4-T cell counts and HIV duration. RESULTS: Carriage of APOE ε4 predicted markedly lower levels of CSF Aß1-42 in univariate (r = -.50; p = .001) and multivariate analyses (R(2) = .25; p < .0003). Greater levels of neurocognitive impairment were associated with higher CSF levels of p-tau in univariate analyses (r = .32; p = .03) and multivariate analyses (R(2) = .10; p = .03). AD risk prediction cut-offs incorporating all three CSF biomarkers suggested that 12.5% of participants had a high risk for AD. Having a CSF-AD like profile was more frequent in those with current (p = .05) and past HIV-associated dementia (p = .03). CONCLUSIONS: Similarly to larger studies, APOE ε4 genotype was not directly associated with HAND, but moderated CSF levels of Aß1-42 in a minority of participants. In the majority of participants, increased CSF p-tau levels were associated with current neurocognitive impairment. Combined CSF biomarker risk for AD in the current HIV+ sample is more than 10 times greater than in the Australian population of the same age. Larger prospective studies are warranted.

HIV-associated neurocognitive disorder in Australia: a case of a high-functioning and optimally treated cohort and implications for international neuroHIV research.

The Australian HIV-infected (HIV+) population is largely comprised of high-functioning men who have sex with men (MSM). Like other English-speaking countries, Australia mostly relies on US neuropsychological normative standards to detect and determine the prevalence of neurological disorders. Whether the US neuropsychological (NP) normative standards are appropriate in Australian HIV+ MSM has not been established. Ninety virally suppressed HIV+ and 49 HIV-uninfected (HIV-) men (respectively 86 and 85 % self-reported MSM; mean age 54 and 56 years, mean premorbid verbal IQ estimate 110 and 111) undertook standard NP testing. The raw neuropsychological data were transformed using the following: (1) US standards as uncorrected scaled scores and demographically corrected T scores (US norms); and (2) z scores (without demographic corrections) derived from Australian comparison group scaled scores (local norms). To determine HIV-associated neurocognitive disorder prevalence, we used a standard definition of impairment based upon a battery-wide summary score: the global deficit score (GDS). Impairment classification (GDS ≥ 0.5) based on the local norms was best at discriminating between the two groups (HIV- = 14.3 % vs. HIV+ = 53.3 %; p < 0.0001). This definition was significantly associated with age. Impairment classification based on the US norms yielded much lower impairment rate regardless of the HIV status (HIV- = 4.1 % vs. HIV+ = 14.7 %; p = 0.05), but was associated with historical AIDS, and not age. Both types of summary scores were associated with reduced independence in activities of daily living (p ≤ 0.03). Accurate neuropsychological classifications of high (or low) functioning individuals may need country-specific norms that correct for performance-based (e.g., reading) estimates of premorbid cognition in addition to the traditional demographic factors.