Redefining Aging in HIV Infection Using Phenotypes

Alzheimer's Disease Pathology in Middle Aged and Older People with HIV: Comparisons with Non-HIV Controls on a Healthy Aging and Alzheimer's Disease Trajectory and Relationships with Cognitive Function

We determined the prevalence of Alzheimer's disease (AD) pathological hallmarks, amyloid-β and phosphorylated-Tau, in autopsied brains of 49 people with HIV (PWH) (ages: 50-68; mean age = 57.0) from the National NeuroAIDS Tissue Consortium and in a comparative cohort of 55 people without HIV (PWoH) from the UC San Diego Alzheimer's Disease Research Center (17 controls, 14 mild cognitive impairment, 24 AD; ages: 70-102, mean age = 88.7). We examined how AD pathology relates to domain-specific cognitive functions in PWH overall and in sex-stratified samples. Amyloid-β and phosphorylated-Tau positivity (presence of pathology of any type/density) was determined via immunohistochemistry in AD-sensitive brain regions. Among PWH, amyloid-β positivity ranged from 19% (hippocampus) to 41% (frontal neocortex), and phosphorylated-Tau positivity ranged from 47% (entorhinal cortex) to 73% (transentorhinal cortex). Generally, AD pathology was significantly less prevalent, and less severe when present, in PWH versus PWoH regardless of cognitive status. Among PWH, positivity for AD pathology related most consistently to memory-related domains. Positivity for p-Tau pathology related to memory-related domains in women with HIV only, although the sample size of women with HIV was small (n = 10). Results indicate that AD pathology is present in a sizable portion of middle aged and older PWH, although not to the extent in older PWoH. Studies with better age-matched PWoH are needed to examine the effect of HIV status on AD pathology.

Epigenetic aging is associated with aberrant neural oscillatory dynamics serving visuospatial processing in people with HIV

BACKGROUND

Despite effective antiretroviral therapy, cognitive impairment and other aging-related comorbidities are more prevalent in people with HIV (PWH) than in the general population. Previous research examining DNA methylation has shown PWH exhibit accelerated biological aging. However, it is unclear how accelerated biological aging may affect neural oscillatory activity in virally suppressed PWH, and more broadly how such aberrant neural activity may impact neuropsychological performance.

METHODS

In the present study, participants (n = 134) between the ages of 23 - 72 years underwent a neuropsychological assessment, a blood draw to determine biological age via DNA methylation, and a visuospatial processing task during magnetoencephalography (MEG). Our analyses focused on the relationship between biological age and oscillatory theta (4-8 Hz) and alpha (10 - 16 Hz) activity among PWH (n=65) and seronegative controls (n = 69).

RESULTS

PWH had significantly elevated biological age when controlling for chronological age relative to controls. Biological age was differentially associated with theta oscillations in the left posterior cingulate cortex (PCC) and with alpha oscillations in the right medial prefrontal cortex (mPFC) among PWH and seronegative controls. Stronger alpha oscillations in the mPFC were associated with lower CD4 nadir and lower current CD4 counts, suggesting such responses were compensatory. Participants who were on combination antiretroviral therapy for longer had weaker theta oscillations in the PCC.

CONCLUSIONS

These findings support the concept of interactions between biological aging and HIV status on the neural oscillatory dynamics serving visuospatial processing. Future work should elucidate the long-term trajectory and impact of accelerated aging on neural oscillatory dynamics in PWH.

Identification of Youthful Neurocognitive Trajectories in Adults Aging with HIV: A Latent Growth Mixture Model

Despite the neurocognitive risks of aging with HIV, initial cross-sectional data suggest a subpopulation of older people with HIV (PWH) possess youthful neurocognition (NC) characteristic of SuperAgers (SA). Here we characterize longitudinal NC trajectories of older PWH and their convergent validity with baseline SA status, per established SuperAging criteria in PWH, and baseline biopsychosocial factors. Growth mixture modeling (GMM) identified longitudinal NC classes in 184 older (age ≥ 50-years) PWH with 1–5 years of follow-up. Classes were defined using ‘peak-age’ global T-scores, which compare performance to a normative sample of 25-year-olds. 3-classes were identified: Class 1_{Stable Elite} (n = 31 [16.8%], high baseline peak-age T-scores with flat trajectory); Class 2_{Quadratic Average} (n = 100 [54.3%], intermediate baseline peak-age T-scores with u-shaped trajectory); Class 3_{Quadratic Low} (n = 53 [28.8%], low baseline peak-age T-scores with u-shaped trajectory). Baseline predictors of Class 1_{Stable Elite} included SA status, younger age, higher cognitive and physiologic reserve, and fewer subjective cognitive difficulties. This GMM analysis supports the construct validity of SuperAging in older PWH through identification of a subgroup with longitudinally-stable, youthful neurocognition and robust biopsychosocial health.

The association between benzodiazepine use and greater risk of neurocognitive impairment is moderated by medical burden in people with HIV

Benzodiazepine use is linked to neurocognitive impairment (NCI) in the general population and people with HIV (PWH); however, this relationship may depend on age-related factors such as medical comorbidities, which occur at an elevated rate and manifest earlier in PWH. We retrospectively examined whether chronological age or medical burden, a clinical marker for aging, moderated the relationship between benzodiazepine use and NCI in PWH. Participants were 435 PWH on antiretroviral therapy who underwent neurocognitive and medical evaluations, including self-reported current benzodiazepine use. A medical burden index score (proportion of accumulated multisystem deficits) was calculated from 28 medical deficits. Demographically corrected cognitive deficit scores from 15 neuropsychological tests were used to calculate global and domain-specific NCI based on established cut-offs. Logistic regressions separately modeled global and domain-specific NCI as a function of benzodiazepine x age and benzodiazepine x medical burden interactions, adjusting for current affective symptoms and HIV disease characteristics. A statistically significant benzodiazepine x medical burden interaction (p = .006) revealed that current benzodiazepine use increased odds of global NCI only among those who had a high medical burden (index score > 0.3 as indicated by the Johnson–Neyman analysis), which was driven by the domains of processing speed, motor, and verbal fluency. No age x benzodiazepine interactive effects on NCI were present. Findings suggest that the relationship between BZD use and NCI among PWH is specific to those with greater medical burden, which may be a greater risk factor for BZD-related NCI than chronological age.

Current Considerations for Clinical Management and Care of People with HIV: Findings from the 11th Annual International HIV and Aging Workshop

The number of people with HIV (PWH) aged 50 years or older continues to steadily increase. The convergence of age- and HIV-related complications in these individuals presents a challenge for both patients and clinicians alike. New findings continue to emerge, as numerous researchers evaluate the combined impact of these two factors on quality of life, physiological systems, and mental health in PWH. Since its first occurrence in 2009, the International Workshop on HIV and Aging has served as a multidisciplinary meeting to share basic biomedical data, clinical trial results, treatment strategies, and epidemiological recommendations, toward better understanding and outcomes among like-minded scientific professionals. In this article, we share a selection of key findings presented in plenary talks at the 11th Annual International Workshop on HIV and Aging, held virtually from September 30, 2020 to October 2, 2020. We will also address the future directions of HIV and aging research, to further assess how the aging process intersects with chronic HIV.

Global burden of hypertension among people living with HIV in the era of increased life expectancy: a systematic review and meta-analysis

BACKGROUND

Although HIV infection and antiretroviral therapy (ART) increase the risk for hypertension in people living with HIV (PLHIV), the global and regional burden of hypertension in PLHIV is not well characterized.

METHODS

In this systematic review and meta-analysis, we searched multiple databases for studies reporting on hypertension in PLHIV and conducted between 2007 and 2018. Meta-analysis through random-effect models served to obtain the pooled prevalence estimates. Heterogeneity was assessed via the χ test on Cochran's Q statistic.

RESULTS

We included 194 studies (396 776 PLHIV from 61 countries). The global prevalence of hypertension was 23.6% [95% confidence interval (95% CI: 21.6-25.5)] with substantial heterogeneity. The regional distribution was Western and Central Europe and North America [28.1% (95% CI: 24.5-31.9)], West and Central Africa [23.5% (16.6-31.0)], Latin America and the Caribbean [22.0% (17.8-26.5)], Eastern and Southern Africa [19.9% (17.2-22.8)], and Asia and Pacific [16.5% (12.5-21.0)]; P = 0.0007. No study originated from the Middle East and North Africa, and Eastern Europe and Central Asia regions. The prevalence was higher in high-income countries than others (P = 0.0003) and higher in PLHIV taking ART than those ART-naive (P = 0.0003). The prevalence increased over time (mainly driven by Eastern and Southern Africa) and with age. There was no difference between men and women. We estimated that in 2018, there were 8.9 (95% CI: 8.3-9.6) million cases of hypertension in PLHIV globally, among whom 59.2% were living in Sub-Saharan Africa.

CONCLUSION

Cost-effective strategies to curb the dreadful burden of hypertension among PLHIV are needed.

Patterns and Predictors of Cognitive Function Among Virally Suppressed Women With HIV

Cognitive impairment remains frequent and heterogeneous in presentation and severity among virally suppressed (VS) women with HIV (WWH). We identified cognitive profiles among 929 VS-WWH and 717 HIV-uninfected women from 11 Women's Interagency HIV Study sites at their first neuropsychological (NP) test battery completion comprised of: Hopkins Verbal Learning Test-Revised, Trail Making, Symbol Digit Modalities, Grooved Pegboard, Stroop, Letter/Animal Fluency, and Letter-Number Sequencing. Using 17 NP performance metrics (T-scores), we used Kohonen self-organizing maps to identify patterns of high-dimensional data by mapping participants to similar nodes based on T-scores and clustering those nodes. Among VS-WWH, nine clusters were identified (entropy = 0.990) with four having average T-scores ≥45 for all metrics and thus combined into an "unimpaired" profile (n = 311). Impaired profiles consisted of weaknesses in: (1) sequencing (Profile-1; n = 129), (2) speed (Profile-2; n = 144), (3) learning + recognition (Profile-3; n = 137), (4) learning + memory (Profile-4; n = 86), and (5) learning + processing speed + attention + executive function (Profile-5; n = 122). Sociodemographic, behavioral, and clinical variables differentiated profile membership using Random Forest models. The top 10 variables distinguishing the combined impaired vs. unimpaired profiles were: clinic site, age, education, race, illicit substance use, current and nadir CD4 count, duration of effective antiretrovirals, and protease inhibitor use. Additional variables differentiating each impaired from unimpaired profile included: depression, stress-symptoms, income (Profile-1); depression, employment (Profile 2); depression, integrase inhibitor (INSTI) use (Profile-3); employment, INSTI use, income, atazanavir use, non-ART medications with anticholinergic properties (Profile-4); and marijuana use (Profile-5). Findings highlight consideration of NP profile heterogeneity and potential modifiable factors contributing to impaired profiles.

Distinguishing Amnestic Mild Cognitive Impairment From HIV-Associated Neurocognitive Disorders

BACKGROUND

Memory impairment occurs in human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) and amnestic mild cognitive impairment (aMCI), the precursor to Alzheimer disease (AD). Methods are needed to distinguish aMCI-associated from HAND-associated impairment in people with HIV (PWH). We developed a neuropsychological method of identifying aMCI in PWH and tested this by relating AD neuropathology (β-amyloid, phospho-Tau) to aMCI versus HAND classification.

METHODS

Seventy-four HIV-positive cases (aged 50-68 years) from the National NeuroAIDS Tissue Consortium had neurocognitive data within 1 year of death and data on β-amyloid and phospho-Tau pathology in frontal brain tissue. High aMCI risk was defined as impairment (<1.0 SD below normative mean) on 2 of 4 delayed recall or recognition outcomes from a verbal and nonverbal memory test (at least 1 recognition impairment required). Differences in β-amyloid and phospho-Tau by aMCI and HAND classification were examined.

RESULTS

High aMCI risk was more common in HAND (69.0%) versus no HAND (37.5%) group. β-amyloid pathology was 4.75 times more likely in high versus low aMCI risk group. Phospho-Tau pathology did not differ between aMCI groups. Neither neuropathological feature differed by HAND status.

CONCLUSIONS

Amnestic mild cognitive impairment criteria that include recognition impairment may help to detect AD-like cognitive/biomarker profiles among PWH.

HIV and three dimensions of Wisdom: Association with cognitive function and physical and mental well-being: For: Psychiatry Research

Wisdom is a unique human personality trait with cognitive, affective or compassionate, and reflective dimensions. We evaluated relationships of three specific dimensions of wisdom with cognitive function and physical and mental well-being in people with HIV (PWH) and HIV-negative (HIV-) participants. Subjects included 138 adults (61 PWH, 77 HIV-) from the San Diego community. Validated measures were used to assess wisdom and well-being. Cognitive function was assessed via the Montreal Cognitive Assessment. We conducted multivariate linear regressions to evaluate the associations of wisdom dimensions with cognitive function and physical and mental well-being. Compared to the HIV- group, PWH had lower mean scores on cognitive function, and physical and mental well-being, and cognitive and reflective dimensions of wisdom, but similar scores on affective or compassionate wisdom. Among PWH, higher total wisdom scores were associated with older age, lower likelihood of substance dependence, greater mental well-being, better cognitive function, higher resilience, social support, and optimism scores, as well as lower levels of perceived stress and nadir CD4 count. Our findings of an association of different dimensions of wisdom with physical and/or mental well-being in PWH would point to a possibility that enhancing these dimensions of wisdom might improve health outcomes in PWH.

[Establishment of a vimentin knockout and HIV-1 gp120 transgenic mouse model]

OBJECTIVE

To construct a HIV-1 gp120 transgenic mice (gp120 Tg) with vimentin (VIM) gene knockout.

METHODS

Female HIV-1 gp120 Tg mice were mated to VIM heterozygote mice (F0). All the offspring mice were derived from these original founders so that both genotypes had the same mixed genetic background. The F1 mice were bred to generate of VIM^+/+, VIM^-/-, VIM^+/+/gp120 Tg and VIM^-/-/gp120 Tg mice. PCR was performed for genotyping of the mice, and the expressions of VIM and gp120 in the brain tissues were examined using immunoblotting.

RESULTS

The results of PCR showed the presence of the target bands in VIM^+/+, VIM^-/-, VIM^+/+/gp120 Tg and VIM^-/-/gp120 Tg mice. In VIM^-/-/gp120 Tg mice, gp120 expression was detected throughout the brain regions while no VIM expression was detected.

CONCLUSIONS

We generated gp120 transgenic mouse models with VIM gene knockout, which facilitate the exploration of the role of VIM in gp120-induced neurotoxicity.

Understanding Comorbidities and Their Contribution to Predictors of Medical Resource Utilization for an Age- and Sex-Matched Patient Population Living With HIV: Cross-Sectional Study

BACKGROUND

More than 60% of people aging with HIV are observed to have multiple comorbidities, which are attributed to a variety of factors (eg, biological and environmental), with sex differences observed. However, understanding these differences and their contribution to medical resource utilization remains challenging as studies conducted exclusively and predominantly among males do not translate well to females, resulting in inconsistent findings across study cohorts and limiting our knowledge of sex-specific comorbidities.

OBJECTIVE

The objective of the study was to provide further insight into aging-related comorbidities, their associated sex-based differences, and their contribution to medical resource utilization, through the analysis of HIV patient data matched by sex.

METHODS

International Classification of Disease 9/10 diagnostic codes that comprise the electronic health records of males (N=229) and females (N=229) were categorized by individual characteristics, chronic and mental health conditions, treatment, high-risk behaviors, and infections and the codes were used as predictors of medical resource utilization represented by Charlson comorbidity scores.

RESULTS

Significant contributors to high Charlson scores in males were age (beta=2.37; 95% CI 1.45-3.29), longer hospital stay (beta=.046; 95% CI 0.009-0.083), malnutrition (beta=2.96; 95% CI 1.72-4.20), kidney failure (beta=2.23; 95% CI 0.934-3.52), chemotherapy (beta=3.58; 95% CI 2.16-5.002), history of tobacco use (beta=1.40; 95% CI 0.200-2.61), and hepatitis C (beta=1.49; 95% CI 0.181-2.79). Significant contributors to high Charlson scores in females were age (beta=1.37; 95% CI 0.361-2.38), longer hospital stay (beta=.042; 95% CI 0.005-0.078), heart failure (beta=2.41; 95% CI 0.833-3.98), chemotherapy (beta=3.48; 95% CI 1.626-5.33), and substance abuse beta=1.94; 95% CI 0.180, 3.702).

CONCLUSIONS

Our findings identified sex-based differences in medical resource utilization. These include kidney failure for men and heart failure for women. Increased prevalence of comorbidities in people living long with HIV has the potential to overburden global health systems. The development of narrower HIV phenotypes and aging-related comorbidity phenotypes with greater clinical validity will support intervention efficacy.

Current Challenges and Solutions in Research and Clinical Care of Older Persons Living with HIV: Findings Presented at the 9th International Workshop on HIV and Aging

In the era of effective antiretroviral therapy, the number of older people with HIV (PWH) is increasing, and those aging with HIV are experiencing an increasing burden of age-associated comorbidities. Life expectancy among older PWH is approaching that of demographically comparable HIV-uninfected (HIV-) adults. With this changing demographic of PWH come new challenges for researchers and clinicians in how to identify, address, and manage the complex interplay of treated HIV infection and aging-associated factors. In response to these challenges, the annual International Workshop on HIV and Aging was initiated in 2009 as a multidisciplinary platform for scientific discourse on the research and clinical complications arising from the aging population of PWH. The multidisciplinary nature of the workshop has resulted in a wide range of topics addressed over the past 9 years, from basic mechanisms in aging and HIV pathogenesis, to epidemiology of aging within large cohorts, interventions, and implementation of clinical programs. Herein, we summarize the key topics discussed at the 9th Annual International Workshop on HIV and Aging 2018, including "inflammaging," mitochondrial dysfunction, exercise interventions, HIV-associated neurocognitive impairment, metabolic dysfunction, menopause, and polypharmacy. In addition to recent developments in research and clinical care, we discuss open questions and future research directions required to better understand the interaction of HIV and aging.

Cognitive Trajectory Phenotypes in Human Immunodeficiency Virus-Infected Patients

OBJECTIVE

The presentation of cognitive impairments in HIV-infected individuals has transformed since the introduction of antiretroviral therapies. Although the overall prevalence of cognitive impairments has not changed considerably, frank dementia is now infrequent, and milder forms of cognitive impairments predominate. Mechanistic insights to the underlying causes of these residual cognitive impairments have been elusive, in part due to the heterogenous etiology of cognitive dysfunction in this population. Here, we sought to categorize longitudinal change in HIV-infected patients based on the performance in specific cognitive domains.

DESIGN

This study consisted of 193 participants from the CHARTER cohort with detailed demographic, clinical, and neuropsychological testing data obtained from 2 study visits interspersed by ∼6 months. Cognitive testing assessed executive function, learning and delayed recall, working memory, verbal fluency, speed of information processing, and motor skills. Change scores were calculated for each domain between the 2 study visits. Dimension reduction and clustering was accomplished by principal component analysis of change scores and k-means clustering to identify cognitive domains that group together and groups of subjects with similar patterns of change.

RESULTS

We identified 4 distinct cognitive change phenotypes that included declines in: (1) verbal fluency, (2) executive function (3) learning and recall, and (4) motor function, with approximately equal numbers of participants in each phenotype.

CONCLUSIONS

Each of the 4 cognitive change phenotypes identify deficits that imply perturbations in specific neural networks. Future studies will need to validate if cognitive change phenotypes are associated with alterations in associated neural pathways.

The current understanding of overlap between characteristics of HIV-associated neurocognitive disorders and Alzheimer's disease

The advent of effective antiretroviral medications (ARVs) has led to an aging of the HIV population with approximately 50% of people with HIV (PWH) being over the age of 50 years. Neurocognitive complications, typically known as HIV-associated neurocognitive disorders (HAND), persist in the era of ARVs and, in addition to risk of HAND, older PWH are also at risk for age-associated, neurodegenerative disorders including Alzheimer's disease (AD). It has been postulated that risk for AD may be greater among PWH due to potential compounding effects of HIV and aging on mechanisms of neural insult. We are now faced with the challenge of disentangling AD from HAND, which has important prognostic and treatment implications given the more rapidly debilitating trajectory of AD. Herein, we review the evidence to date demonstrating both parallels and differences in the profiles of HAND and AD. We specifically address similarities and difference of AD and HAND as it relates to (1) neuropsychological profiles (cross-sectional/longitudinal), (2) AD-associated neuropathological features as evidenced from neuropathological, cerebrospinal fluid and neuroimaging assessments, (3) biological mechanisms underlying cortical amyloid deposition, (4) parallels in mechanisms of neural insult, and (5) common risk factors. Our current understanding of the similarities and dissimilarities of AD and HAND should be further delineated and leveraged in the development of differential diagnostic methods that will allow for the early identification of AD and more suitable and effective treatment interventions among graying PWH.

Psychosocial Correlates of Frailty Among HIV-Infected and HIV-Uninfected Adults

Frailty is a geriatric condition characterized by increased vulnerability to physical impairments and limitations that may lead to disabilities and mortality. Although studies in the general population suggest that psychosocial factors affect frailty, less is known about whether similar associations exist among people living with HIV (PLWH). The purpose of this study was to examine psychosocial correlates of frailty among PLWH and HIV-uninfected adults. Our sample included 127 adults (51% PLWH) participating in the Multi-Dimensional Successful Aging among HIV-Infected Adults study at the University of California San Diego (average age 51 years, 80% male, 53% White). Frailty was assessed via the Fried Frailty Index. Psychosocial variables significant in bivariate models were included in principal component analysis to generate factor variables summarizing psychosocial correlates. Multivariate logistic regression models were fit to examine the independent effects of factor variables and their interaction terms with HIV status. In bivariate models, frailty was associated with multiple psychosocial variables, for example, grit, optimism, personal mastery, social support, emotional support. Factor analysis revealed that psychosocial variables loaded on two factors-Positive Resources/Outlook and Support by Others. The multivariate model showed significant main effects of Support by Others and HIV status, and interactive effects HIV X Positive Resources/Outlook, such that Positive Resources/Outlook was negatively associated with frailty for PLWH but not for HIV-uninfected individuals. These analyses indicate that psychosocial factors may be associated with frailty among PLWH. Positive resources and outlook may play a role in frailty prevention. Future longitudinal studies are needed to establish causal links.