Sex-based differences in neurocognitive functioning in HIV-infected young adults

Cognitive impairment and neurocognitive profiles among people living with HIV and HIV-negative individuals older over 50 years: a comparison of IHDS, MMSE and MoCA

We aimed to examine the l differences in the assessment of neurocognitive impairment (NCI) using cognitive screening tools between PLWH and HIV-negative individuals and further compare the neurocognitive profiles between the two groups. This was baseline evaluation of Pudong HIV Aging Cohort, including 465 people living with HIV (PLWH) and 465 HIV-negative individuals aged over 50 years matched by age (± 3 years), sex and education. NCI was assessed using the Chinese version of Mini-mental State Examination (MMSE), the International HIV Dementia Scale (IHDS) and Beijing version of Montreal Cognitive Assessment (MoCA). In total, 258 (55.5%), 91 (19.6%), 273 (58.7%) of PLWH were classified as having NCI by the IHDS, MMSE and MoCA, compared to 90 (19.4%), 25 (5.4%), 135 (29.0%) of HIV-negative individuals, respectively (p < 0.05); such associations remained significant in multivariable analysis. PLWH showed a larger overlap of NCI detected by IHDS, MMSE, and MoCA. IHDS and MoCA detected almost all of the NCI detected by MMSE. IHDS-motor and psychomotor speeds and MoCA-executive function showed the greatest disparities between two groups. In multivariable analysis, older age and more depressive symptoms were positively associated with NCI regardless of the screening tools or HIV serostatus. PLWH over 50 years old display a higher prevalence of NCI and distinct neurocognitive profiles compared to HIV-negative individuals, despite viral suppression. Given the more considerable overlap in NCI classification in PLWH, it is advisable to choose one screening tool such as IHDS or MoCA to identify those potentially having NCI and then refer to more comprehensive neuropsychological assessment.

Sex differences in cognitive function among people with HIV-1 clade C infection in Northern India

Human immunodeficiency virus-1 (HIV-1) clade C is the most prevalent form of HIV-1 comprising nearly 46% of global infections and is the dominant subtype in India. Despite its predominance, the impact of HIV-1 clade C infection on cognitive function has been understudied in comparison with other subtypes, notably clade B, which is primarily found in Europe and North America. Few studies have assessed cognitive impairment in antiretroviral therapy (ART) naïve men and women with HIV-1 clade C infection. In this study conducted in Northern India, differences in neuropsychological functioning were compared between 109 participants (70 men, 39 women) with untreated HIV-1 clade C infection and 110 demographically matched healthy controls (74 men, 36 women). A comprehensive neuropsychological battery was used to examine depression, self-assessment of functioning, and cognitive performance in six domains of functioning. Group differences were assessed by HIV-1 status and sex, controlling for age and education. Results indicated that cognitive deficits were substantially greater among male participants with HIV-1 clade C compared to male controls in all domains of cognitive functioning; in contrast, women with HIV-1 clade C had only minor deficits compared to healthy female participants. In addition, a larger proportion of men with HIV-1 clade C exhibited high levels of depression than women with HIV-1 clade C. These findings suggest that untreated HIV-1 clade C infection in men can have debilitating effects on neuropsychological function and depression, and stress the importance of facilitating rapid access to treatment to reduce the impact of HIV-1 infection.

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

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

Sex Differences in the Cognitive Performance of a South African Cohort of People With HIV and Comorbid Major Depressive Disorder

Women with HIV (WWH) may be more vulnerable to cognitive impairment than men with HIV (MWH), which may be explained by the direct effects of HIV or by sociodemographic and psychiatric characteristics. We recruited 105 people with HIV (PWH; 76 women) with incomplete antiretroviral therapy adherence, comorbid major depressive disorder, and socioeconomically disadvantaged backgrounds. Participants completed neuropsychological testing and measures gathering sociodemographic, medical, and psychiatric information. We compared WWH and MWH cognitive performance using unadjusted and adjusted regressions, and within each respective group, we explored predictors of cognitive performance. Results showed no significant between-sex differences in cognitive performance, both globally and within domains. Fewer years of education (β = 0.94), illiteracy (β = 4.55), and greater food insecurity (β = -0.28) predicted lower cognitive performance in WWH but not MWH. We conclude that sex differences in PWH are likely due to sample characteristics representing broader inequalities, rather than true biological differences.

Difference in the neurocognitive functions of WLWH and MLWH in an Italian cohort of people living with HIV

Based on the available literature, women living with HIV (WLWH) seem to show greater cognitive and emotional disadvantages than men living with HIV (MLWH). Our aim was to compare the cognitive performance of MLWH and WLWH in an Italian cohort of People Living With HIV (PLWH) and to analyse factors potentially contributing to sex differences in cognitive function. We ran a retrospective, cross-sectional analysis of a monocentric dataset of PLWH who were administered a standardized neuropsychological test battery (SNB) during routine clinical care. We enrolled 161 Italian PLWH who are on combined antiretroviral therapy (cART): 114 (70.8%) MLWH and 47 (29.2%) WLWH.

Global cognitive performance (composite z score) (GCP) was significantly higher in MLWH than WLWH [mean 0.19 (SD 0.85) vs − 0.13 (SD 0.96); p = 0.039]. Moreover, WLWH obtained significantly higher scores on the Zung Depression Scale than MLWH [mean 41.8 (SD 10.9) vs 36.7 (SD 9.2); p = 0.003]. However, there was no statistically significant direct effect between male sex and better GCP (p = 0.692) in the context of a mediation model. On the contrary, the associations between male sex and better GCP were mediated by higher level of education (a*b =  + 0.15, Bootstrap CI95 = 0.05 and 0.27) and a lower Zung depression score (a*b =  + 0.10, Bootstrap CI95 = 0.02 and 0.21).

In conclusion, the global cognitive performance of WLWH is lower than that of MLWH. However, other demographic and clinical factors besides sex might help explain differences in their neurocognitive functions and make it possible for us to monitor them and identify those patients most in need.

Sex Differences in Non-AIDS Comorbidities Among People With Human Immunodeficiency Virus

Women are grossly underrepresented in human immunodeficiency virus (HIV) clinical and translational research. This is concerning given that people with HIV (PWH) are living longer, and thus accumulating aging-related non-AIDS comorbidities (NACMs); emerging evidence suggests that women are at higher risk of NACM development and progression compared with men. It is widely recognized that women vs men have greater immune activation in response to many viruses, including HIV-1; this likely influences sex-differential NACM development related to differences in HIV-associated chronic inflammation. Furthermore, many sociobehavioral factors that contribute to aging-related NACMs are known to differ by sex. The objectives of this review were to (1) synthesize sex-stratified data on 4 NACMs among PWH: bone disease, cardiovascular disease, metabolic dysfunction, and neurocognitive impairment; (2) evaluate the characteristics of key studies assessing sex differences in NACMs; and (3) introduce potential biological and psychosocial mechanisms contributing to emerging trends in sex-differential NACM risk and outcomes among PWH.

Development of a Nomogram-Based Tool to Predict Neurocognitive Impairment Among HIV-positive Charter Participants

Background:

Despite the widespread use of combination antiretroviral therapy (cART), HIV-associated neurocognitive impairment (NCI) persists in people living with HIV (PLWH). Studies have generated inconsistent results regarding etiological factors for NCI in PLWH. Furthermore, a user-friendly and readily available predictive tool is desirable in clinical practice to screen PLWH for NCI.

Objective:

This study aimed to identify factors associated with NCI using a large and diverse sample of PLWH and build a nomogram based on demographic, clinical, and behavioral variables.

Methods:

We performed Bayesian network analysis using a supervised learning technique with the Markov Blanket (MB) algorithm. Logistic regression was also conducted to obtain the adjusted regression coefficients to construct the nomogram.

Results:

Among 1,307 participants, 21.6% were neurocognitively impaired. During the MB analysis, age provided the highest amount of mutual information (0.0333). Logistic regression also showed that old age (>50 vs. ≤50 years) had the strongest association (OR=2.77, 95% CI=1.99-3.85) with NCI. The highest possible points on the nomogram were 626, translated to a nomogram-predicted probability of NCI to be approximately 0.95. The receiver operating characteristic (ROC) curve's concordance index was 0.75, and the nomogram's calibration plot exhibited an excellent agreement between observed and predicted probabilities.

Conclusion:

The nomogram used variables that can be easily measured in clinical settings and, thus, easy to implement within a clinic or web-interface platform. The nomogram may help clinicians screen for patients with a high probability of having NCI and thus needing a comprehensive neurocognitive assessment for early diagnosis and appropriate management.

Cognitive Differences between Men and Women with HIV: A Systematic Review and Meta-Analysis

OBJECTIVE

Although many studies report that women with HIV (WWH) are more vulnerable to cognitive impairment than men with HIV (MWH), this trend is not described consistently in the literature. In this systematic review and meta-analysis, we investigated whether the weight of evidence supports the existence of a significant sex difference in cognitive functioning among people with HIV and, if so, whether specific domains are affected.

METHOD

A systematic literature search retrieved 4,062 unique articles published between January 2000 and June 2019. Eligibility criteria were that studies directly compared adult WWH and MWH using a neuropsychological test battery. After extensive screening, we included 11 studies in the systematic review (N = 3,333) and 6 in the meta-analysis (N = 2,852).

RESULTS

Six studies included in the systematic review found WWH performed significantly more poorly on measures of cognitive performance than MWH; the other five found no sex differences. Meta-analytic results indicated that WWH performed significantly more poorly than MWH in three cognitive domains (psychomotor coordination, visuospatial learning, and memory), but magnitudes of effect sizes were small (d = -.16, -.43, and - .30, respectively). Analyses detected no sex differences in global cognitive functioning and in the other cognitive domains.

CONCLUSIONS

Sex differences in cognitive performance are small, and sociodemographic and psychiatric characteristics of WWH and MWH differ between studies. Cognitive differences between WWH and MWH may be explained by sex-based variation in these characteristics, the impact of which seems to outweigh that of HIV-related clinical variables (e.g., CD4 count and viral load).

Blood-Brain Barrier Impairment in Patients Living with HIV: Predictors and Associated Biomarkers

Despite the substantial changes resulting from the introduction of combination antiretroviral therapy (cART), the prevalence of HIV-associated neurocognitive disorders (HAND) remains substantial. Blood-brain barrier impairment (BBBi) is a frequent feature in people living with HIV (PLWH) and it may persist despite effective antiretroviral treatment. A cross-sectional study was performed in PLWH who underwent lumbar puncture for clinical reasons or research protocols and several cerebrospinal fluid biomarkers were studied. BBBi was defined as cerebrospinal fluid-to-serum albumin ratio (CSAR) >6.5 (<40 years) or >8 (>40 years). We included 464 participants: 147 cART-naïve and 317 on cART. Male sex was prevalent in both groups (72.1% and 72.2% respectively); median age was 44 (38-52) years in naïve and 49 (43-57) years in treated subjects. BBBi was observed in 35.4% naïve and in 22.7% treated participants; the use of integrase inhibitors was associated with a lower prevalence (18.3 vs. 30.9%, p = 0.050). At multivariate binary logistic regression (including age and sex) nadir CD4 cell count (p = 0.034), presence of central nervous system (CNS) opportunistic infections (p = 0.024) and cerebrospinal fluid (CSF) HIV RNA (p = 0.002) in naïve participants and male sex (p = 0.021), a history of CNS opportunistic infections (p = 0.001) and CSF HIV RNA (p = 0.034) in treated patients were independently associated with BBBi. CSF cells and neopterin were significantly higher in participants with BBBi. BBBi was prevalent in naïve and treated PLWH and it was associated with CSF HIV RNA and neopterin. Systemic control of viral replication seems to be essential for BBB integrity while sex and treatment influence need further studies.

Mini-review: The therapeutic role of cannabinoids in neuroHIV

In the era of combined antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) is considered a chronic disease with an inflammatory component that specifically targets the brain and causes a high prevalence of HIV-1-associated neurocognitive disorders (HAND). The endocannabinoid (eCB) system has attracted interest as a target for treatment of neurodegenerative disorders, due to the potential anti-inflammatory and neuroprotective properties of cannabinoids, including its potential therapeutic use in HIV-1 neuropathogenesis. In this review, we summarize what is currently known about the structural and functional changes of the eCB system under conditions of HAND. This will be followed by summarizing the current clinical and preclinical findings on the effects of cannabis use and cannabinoids in the context of HIV-1 infection, with specifically focusing on viral load, cognition, inflammation, and neuroprotection. Lastly, we present some potential future directions to better understand the involvement of the eCB system and the role that cannabis use and cannabinoids play in neuroHIV.

Sex Differences in the Patterns and Predictors of Cognitive Function in HIV

Despite advancements in antiretroviral therapy, mild cognitive deficits persist in nearly half of people with HIV (PWH). The profile of impairment in HIV is highly variable with deficits observed in a range of cognitive domains. Despite evidence of greater cognitive impairment among women with HIV (WWH) vs. men with HIV (MWH), it is unclear how MWH and WWH differ in the type of cognitive impairment and in risk factors associated with cognitive impairment profiles. In a large and well-characterized sample of PWH, we used machine learning to identify profiles of cognitive functioning and their associated factors overall and within sex. Participants included 1,666 PWH (201 WWH; 1,465 MMH) from the HIV Neurobehavioral Research Program who completed a neuropsychological test battery at their baseline visits. Using demographically-adjusted T-scores from 13 test outcomes assessing motor skills, executive functioning, attention/working memory, episodic learning and memory, verbal fluency, and processing speed, we used Kohonen self-organizing maps to identify patterns of high-dimensional data by mapping participants to similar nodes based on T-scores (MCLUST R package). Random forest models were used to determine how sociodemographic (e.g., age, education), clinical (e.g., depressive symptoms, substance use disorder), and biological (e.g., HIV disease characteristics) factors differentially related to membership within a cognitive profile. All analyses were repeated within sex. Three cognitive profiles were identified overall and within each sex. Overall and within MWH, there were unimpaired and global weakness profiles. The third profile in the total sample demonstrated relatively weak auditory attention whereas in MWH showed relative strengths in attention and processing speed. Conversely, there was no unimpaired profile among WWH. Rather, WWH demonstrated separate profiles reflecting weakness in motor skills, a relative weakness in learning and delayed recall, and global weaknesses with spared recognition memory. Despite different cognitive profiles by sex, the most discriminative factors were similar between men and women and included reading level (cognitive reserve), current and nadir CD4 count, plasma HIV viral load, duration of HIV disease, age, depressive symptoms, and race/ethnicity. Findings fill a knowledge gap concerning sex differences in cognitive impairment in PWH and inform personalized risk reduction and therapeutic strategies.

Immuno-inflammatory changes across phases of early psychosis: The impact of antipsychotic medication and stage of illness

INTRODUCTION

Research examining the role of inflammation in psychosis has produced inconsistent results. Variables that influence inflammation, including antipsychotic medication, are inconsistently controlled across studies and variation of inflammatory analytes across stages of psychosis may also influence findings. The purpose of this study was to assess for evidence of immuno-inflammatory dysregulation across the stages of early psychosis. We examined a immuno-inflammatory analytes in subjects at clinical high risk (CHR) for developing a psychotic disorder, antipsychotic-naïve (-n) and antipsychotic treated (-a) subjects in their first episode of psychosis (FEP), and healthy control (HC) subjects.

METHODS

A total of 11 subjects at CHR, 50 subjects within their FEP (40 FEP-n, 10 FEP-a), and 10 HC subjects were recruited from early psychosis programs in San Diego and Mexico City. Plasma was collected for biomarker assay.

RESULTS

Immuno-inflammatory analytes significantly differed between groups: Interferon-gamma (IFN-γ), Interleukin-10 (IL-10), Eotaxin-1, Interferon Gamma-Induced Protein-10 (IP-10), Monocyte Chemotactic Protein-1 (MCP-1), Macrophage-Derived Chemokine (MDC), Macrophage Inflammatory Protein-1 beta (MIP-1β), Thymus and Activation Regulated Chemokine (TARC), and Brain Derived Neurotropic Factor (BDNF). Post-hoc analyses revealed an overall pattern of higher levels of IL-10, MCP-1, MIP-1β, TARC, and BDNF in CHR as compared to FEP-a, FEP-n, and HC subjects.

CONCLUSIONS

Results reveal a profile of immuno-inflammatory dysregulation in early stages of psychosis prior to psychotic conversion and treatment with antipsychotic medication. The CHR phase of early psychosis may represent a period of increased immuno-inflammatory activation, but due to limited sample size, these results deserve replication in a well characterized early psychosis population.

Effects of HIV infection, antiretroviral therapy, and immune status on the speed of information processing and complex motor functions in adult Cameroonians

HIV-associated neurocognitive deficits include impaired speed-of-information processing (SIP) and motor functions. There is lack of Cameroonian adult norms for assessing SIP or motor functions. This study of 683 Cameroonians (320 HIV+, 363 HIV-) establishes demographically-adjusted norms for six SIP [Wechsler-Adult-Intelligence-Scale (WAIS)-III Digit Symbol (WAIS-IIIDS) and Symbol Search (WAIS-IIISS), Stroop Color-Naming, Stroop Word-Reading, Trail-Making Test-A (TMT-A), Color Trails-1 (CTT1)], and two motor function [Grooved Pegboard-dominant (GP-DH) and non-dominant (GP-NDH) hands] tests. We assessed viral effects on SIP and motor functions. HIV-infected persons had significantly lower (worse) T scores on GP-DH, WAIS-IIIDS, Stroop Word-Reading, TMT-A; lower motor and SIP summary T scores. Significantly higher proportion of cases (20.7%) than controls (10.3%) had impaired SIP. Male cases had better T scores than female cases on GP-NDH, WAIS-IIIDS, WAIS-IIISS, TMT-A, CTT1; better SIP summary T scores. Antiretroviral therapy (ART) was associated with significantly better T scores on GP-NDH, WAIS-IIIDS, Stroop Color-Naming; better motor and SIP summary T scores. Cases with higher CD4 had better T scores on WAIS-IIIDS, TMT-A, CTT1; better SIP summary T scores. Overall, we demonstrate that HIV infection in Cameroon is associated with deficits in SIP and motor functions; ART and higher CD4 are associated with better cognitive performance. We provide SIP and psychomotor functions normative standards, which will be useful for neurobehavioral studies in Cameroon of diseases affecting the brain.

Neurocognitive Impairment in the Combined Antiretroviral Therapy Era in a Romanian Cohort of Young Adults with Chronic HIV Infection

HIV-associated neurocognitive disorders (HAND) continue to be reported even in patients with successful antiretroviral treatment. We investigated the prevalence of neurocognitive impairment and possible HIV-associated determinants of cognition in a Romanian cohort of young adults, parenterally infected with HIV during their first years of life. Two hundred fourteen treatment-experienced HIV-positive individuals [median age: 24 years, males: 48%, median duration on combined antiretroviral therapy (cART): 12 years] underwent standard immunologic and virological monitoring and antiretroviral resistance testing using pol gene sequencing in both plasma and, when available, cerebrospinal fluid (CSF) paired samples. Neurocognitive impairment was assessed using a comprehensive neuropsychological test battery, and a global deficit score (GDS) was calculated (cutoff ≥0.5). Cognitive impairment was detected in 35% of the study participants, without any association with sex, median age, CD4 cell count (actual or nadir), CSF and plasma viral load (actual or zenith), AIDS diagnosis, duration of HIV infection, and cART characteristics. Participants carrying resistant viruses tended to be more frequently cognitively impaired (p = 0.36), with a higher median GDS value (p = 0.06) compared with participants harboring wild-type HIV, although the figures did not reach statistical significance. No signs of virological compartmentalization were observed based on CSF versus plasma viral load and on the profile of pol sequences. A moderate rate of mild neurocognitive impairment is still present in young adults with chronic HIV infection acquired in early childhood despite successful cART, without any association with classic markers of HIV infection. New biomarkers reflecting persistent central nervous system inflammation and neuronal injury may be more relevant for the development of HAND.

Greater Sensorimotor Deficits and Abnormally Lower Globus Pallidus Fractional Anisotropy in HIV+ Women than in HIV+ Men

AIMS

Cognitive impairment may be greater in HIV-positive (HIV+) women than in HIV+ men. Whether sex-specific differences exist in brain microstructure of HIV+ individuals is unknown and was evaluated.

METHOD

39 HIV+ (21 men, 18 women) and 45 seronegative (SN, 20 men, 25 women) participants were assessed with brain diffusion tensor imaging and cognitive assessments (7 neuropsychological domains). Fractional anisotropy (FA) and mean diffusivity (MD) were measured with an automated atlas in selected brain regions. Group comparisons were assessed with linear mixed effects models, with sub-regions and hemisphere (left/right) as repeated factors for each region.

RESULTS

HIV+ women, but not HIV+ men, were slower than sex-matched SN controls on sensorimotor function (Dominant-hand: interaction-p = 0.007; Non-dominant hand: interaction-p = 0.039). Similarly, only HIV+ women had lower FA in the globus pallidus (GP, interaction-p = 0.011). Additionally, regardless of sex, the HIV+ group had poorer Fluency, Speed, and Attention than SN-controls (p = 0.006-0.008), as well as lower FA and higher MD in multiple brain regions (p = <0.001-0.044). Across all participants, performance on Attention was predicted by uncinate-FA (p < 0.001, r = 0.5) and corpus callosum (CC)-FA (p = 0.038, r = 0.23), while the Speed of Information Processing was predicted by CC-FA (p = 0.009, r = 0.3). Furthermore, faster sensorimotor function correlated with higher CC-FA and uncinate-FA in men but not in women (Sex*DTI-interaction-p = 0.03-0.06).

CONCLUSIONS

The relatively poorer sensorimotor function and abnormally lower GP_FA, suggesting lesser neuronal integrity, in HIV+ women demonstrate sex-specific effects from HIV-infection on these measures. These findings may be related to the greater immune activation and neuroinflammation in HIV+ women compared to HIV+ men. Graphical Abstract.

HIV-1 infection alters energy metabolism in the brain: Contributions to HIV-associated neurocognitive disorders

The brain is particularly sensitive to changes in energy supply. Defects in glucose utilization and mitochondrial dysfunction are hallmarks of nearly all neurodegenerative diseases and are also associated with the cognitive decline that occurs as the brain ages. Chronic neuroinflammation driven by glial activation is commonly implicated as a contributing factor to neurodegeneration and cognitive impairment. Human immunodeficiency virus-1 (HIV-1) disrupts normal brain homeostasis and leads to a spectrum of HIV-associated neurocognitive disorders (HAND). HIV-1 activates stress responses in the brain and triggers a state of chronic neuroinflammation. Growing evidence suggests that inflammatory processes and bioenergetics are interconnected in the propagation of neuronal dysfunction. Clinical studies of people living with HIV and basic research support the notion that HIV-1 creates an environment in the CNS that interrupts normal metabolic processes at the cellular level to collectively alter whole brain metabolism. In this review, we highlight reports of abnormal brain metabolism from clinical studies and animal models of HIV-1. We also describe diverse CNS cell-specific changes in bioenergetics associated with HIV-1. Moreover, we propose that attention should be given to adjunctive therapies that combat sources of metabolic dysfunction as a mean to improve and/or prevent neurocognitive impairments.

Sex Differences in Neurocognitive Function in Adults with HIV: Patterns, Predictors, and Mechanisms

PURPOSE OF REVIEW

Sex differences in cognitive function are well documented yet few studies had adequate numbers of women and men living with HIV (WLWH; MLWH) to identify sex differences in neurocognitive impairment (NCI) and the factors contributing to NCI. Here, we review evidence that WLWH may be at greater risk for NCI.

RECENT FINDINGS

We conducted a systematic review of recent studies of NCI in WLWH versus MLWH. A power analysis showed that few HIV studies have sufficient power to address male/female differences in NCI but studies with adequate power find evidence of greater NCI in WLWH, particularly in the domains of memory, speed of information processing, and motor function. Sex is an important determinant of NCI in HIV, and may relate to male/female differences in cognitive reserve, comorbidities (mental health and substance use disorders), and biological factors (e.g., inflammation, hormonal, genetic).

Plasma CXCL10 correlates with HAND in HIV-infected women

HIV-associated neurocognitive disorder (HAND) is characterized by chronic immune activation. We aimed to identify biomarkers associated with HAND and to investigate their association with cognitive function and sex, in a homogenous cohort of HIV-infected (HIV+) young adults, parenterally infected during early childhood. One hundred forty-four HIV+ Romanian participants (51% women) without major confounders underwent standardized neurocognitive and medical evaluation in a cross-sectional study. IFN-γ, IL-1β, IL-6, CCL2, CXCL8, CXCL10, and TNF-α were measured in plasma in all participants and in cerebrospinal fluid (CSF) in a subgroup of 56 study participants. Biomarkers were compared with neurocognitive outcomes, and the influence of sex and HIV disease biomarkers was assessed. In this cohort of young adults (median age of 24 years), the rate of neurocognitive impairment (NCI) was 36.1%. Median current CD4+ count was 479 cells/mm³ and 36.8% had detectable plasma viral load. Women had better HIV-associated overall status. In plasma, controlling for sex, higher levels of IL-6 and TNF-α were associated with NCI (p < 0.05). Plasma CXCL10 showed a significant interaction with sex (p = 0.02); higher values were associated with NCI in women only (p = 0.02). Individuals with undetectable viral load had significantly lower plasma CXCL10 (p < 0.001) and CCL2 (p = 0.02) levels, and CSF CXCL10 (p = 0.01), IL-6 (p = 0.04), and TNF-α (p = 0.04) levels. NCI in young men and women living with HIV was associated with higher IL-6 and TNF-α in plasma, but not in the CSF. CXCL10 was identified as a biomarker of NCI specifically in women with chronic HIV infection.

Sex-specific neurogenic deficits and neurocognitive disorders in middle-aged HIV-1 Tg26 transgenic mice

Varying degrees of cognitive deficits affect over half of all HIV-1 infected patients. Because of antiretroviral treatment (ART) regimens, the HIV-1 patient population is increasing in age. Very few epidemiological studies have focused on sex-specific differences in HIV-1-associated neurocognitive disorders (HAND). The purpose of this study is to examine any possible differences between male and female mice in the progression of cognitive dementia during persistent low-level HIV-1 protein exposure, mimicking the typical clinical setting in the post-ART era. Eight to ten-month old HIV-1 Tg26(+/-) transgenic mice were utilized to assess for specific learning and memory modalities. Initial physiological screening and fear conditioning assessments revealed that Tg26 mice exhibited no significant differences in general behavioral function, contextual fear conditioning, or cued fear conditioning responses when compared to their wild-type (WT) littermates, regardless of sex. However, Barnes maze testing revealed significantly impaired short and long-term spatial memory in males, while females had impaired spatial learning abilities and short-term spatial memory. The potential cellular mechanism underlying these sex-specific neurocognitive deficits was explored with hippocampal neurogenic analysis. Compared to WT mice, both male and female Tg26(+/-) mice had fewer quiescent neural stem cells and neuroblasts in their hippocampi. Male Tg26(+/-) mice had a more robust reduction of the quiescent neural stem cell pool than female Tg26(+/-) mice. While female WT mice had a higher number of neural progenitor cells than male WT mice, only female Tg26(+/-) mice exhibited a robust reduction in the number of neural progenitor cells. Altogether, these results suggest that middle-aged male and female Tg26(+/-) mice manifest differing impairments in cognitive functioning and hippocampal neurogenesis. This study emphasizes the importance of understanding sex related differences in HAND pathology, which would aid in designing more optimized therapeutic regimens for the treatment of HAND.

Sex differences in neurocognitive screening among adults living with HIV in China

HIV-infected (HIV+) women may be more vulnerable to neurocognitive impairment (NCI) due to psychological and physiological factors but previous studies show mixed findings. We investigated the neurocognitive performances in HIV+ versus HIV- women and men. This cross-sectional analysis included 669 HIV+ patients (223 women) and 1338 HIV-uninfected (HIV-) controls (446 women) which were frequency matched on sex, education, and 5-year age categories. NCI was screened using the Mini-mental State Examination. Psychomotor speed was assessed using timed alternating hand sequence test. Prevalence of NCI was higher among women versus men in the HIV+ group (16.1% vs 10.5%) but not the HIV- group (4.3% vs 3.5%). HIV+ women performed worse compared to men on psychomotor speed, orientation, attention, and calculation, whereas HIV- women performed worse compared to men on attention and calculation. Adjusted interaction effects of HIV status × sex (women vs men) were significant on orientation, attention, and calculation, and marginally significant on psychomotor speed (p = 0.053). In multivariable models, among both HIV+ women and men, less years of education and depressive symptoms were associated with NCI. Waist-to-hip ratio above the cut-off was strongly associated with NCI among HIV+ women. HIV+ women perform worse on cognitive measures compared to HIV+ men. The association of central obesity with NCI in HIV+ women should be noted.

Neurocognitive Complications of HIV Infection in Women: Insights from the WIHS Cohort

Although sex differences in brain function and brain disorders are well documented, very few studies have had adequate number of women to address sex-related factors contributing to HIV-associated brain dysfunction. Compared to men living with HIV (MLWH), women living with HIV (WLWH) may be at greater risk for cognitive dysfunction and decline due to biological factors (e.g., hormonal, immunologic) and issues common in underserved communities including poverty, low literacy levels, mental health and substance abuse, barriers to health-care services, and environmental exposures. To address this issue, we review relevant cross-sectional and longitudinal findings from the Women's Interagency HIV Study (WIHS), the largest study of the natural and treated history of WLWH, as well as other studies focusing on cognitive complications of HIV in women. We provide evidence that WLWH are more cognitively vulnerable than MLWH and that there are differences in the pattern of cognitive impairment. We next discuss factors that contribute to these differences, including biological factors (e.g., inflammation, hormonal, genetic) as well as common comorbidities (mental health, substance use, vascular and metabolic risk factors, coinfections and liver function, non-antiretroviral medications, and genetic markers). These findings demonstrate the importance of considering sex as a biological factor in studies of cognitive dysfunction and suggest avenues for future research.

Interferon-α-Mediated Activation of T Cells from Healthy and HIV-Infected Individuals Is Suppressed by Δ9-Tetrahydrocannabinol

Patients with HIV routinely use medicinal cannabinoids to treat neuropathic pain, anxiety, and human immunodeficiency virus (HIV)-associated wasting. However, Δ⁹-tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in cannabis, suppresses T-cell function and secretion of interferons, both critically important in the antiviral immune response. Interferon-α (IFNα), a key cytokine in T-cell activation and peripheral control of HIV infection, can potentiate responsiveness to interleukin-7 (IL-7), a crucial homeostatic cytokine for peripheral T-cell maintenance. The objective of this investigation was to compare the response of T cells to stimulation by IFNα and IL-7 in T cells from healthy and HIV⁺ donors in the absence and presence of THC. To compare T-cell responses between healthy and HIV⁺ donors signaling through IFNα receptor, IFNα-induced expression of IL-7α receptor (IL-7Rα), cognate signaling through IL-7R, and on IL-7-mediated T-cell proliferation were measured by flow cytometry and real-time quantitative polymerase chain reaction. CD8⁺ T cells from HIV⁺ donors showed a diminished response to IFNα-induced phosphorylated signal transducer and activator of transcription-1 activation compared with CD8⁺ T cells from healthy donors, whereas CD4⁺ T cells from HIV⁺ donors and healthy donors were comparable. Treatment with IFNα promoted IL-7R expression and potentiated IL-7-induced STAT5 phosphorylation to augment IL-7-mediated proliferation by T cells from healthy and HIV⁺ donors. Finally, HIV⁺ donors exhibited reduced sensitivity to THC-mediated suppression by IFNα- and IL-7-mediated stimulation compared with healthy donors. These results further support THC as being immune suppressive while identifying putatively beneficial aspects of cannabinoid-based therapies in HIV⁺ patients.