Co-factors in HIV neurobehavioural disturbances: substance abuse, hepatitis C and aging

Effects of comorbidity burden and age on brain integrity in HIV

OBJECTIVE

The influence of confounding neurocognitive comorbidities in people living with HIV (PLWH) on neuroimaging has not been systematically evaluated. We determined associations between comorbidity burden and brain integrity and examined the moderating effect of age on these relationships.

DESIGN

Observational, cross-sectional substudy of the CNS HIV Antiretroviral Therapy Effects Research cohort.

METHODS

A total of 288 PLWH (mean age = 44.2) underwent structural MRI and magnetic resonance spectroscopy as well as neurocognitive and neuromedical assessments. Consistent with Frascati criteria for HIV-associated neurocognitive disorders (HAND), neuromedical and neuropsychiatric comorbidity burden was classified as incidental (mild), contributing (moderate), or confounding (severe-exclusionary) to a diagnosis of HAND. Multiple regression modeling predicted neuroimaging outcomes as a function of comorbidity classification, age, and their interaction.

RESULTS

Comorbidity classifications were 176 incidental, 77 contributing, and 35 confounded; groups did not differ in HIV disease characteristics. Relative to incidental and contributing participants, confounded participants had less cortical gray matter and more abnormal white matter and ventricular cerebrospinal fluid, alongside more neuroinflammation (choline, myo-inositol) and less neuronal integrity (N-acetylaspartate). Older age exacerbated the impact of comorbidity burden: to a greater extent in the confounded group, older age was associated with more abnormal white matter (P = 0.017), less total white matter (P = 0.015), and less subcortical gray matter (P = 0.014).

CONCLUSION

Neuroimaging in PLWH reveals signatures associated with confounding neurocognitive conditions, emphasizing the importance of evaluating these among individuals with suspected HAND. Older age amplifies subcortical and white matter tissue injury, especially in PLWH with severe comorbidity burden, warranting increased attention to this population as it ages.

The effects of HIV and aging on subcortical shape alterations: A 3D morphometric study

Standard volumetric neuroimaging studies have demonstrated preferential atrophy of subcortical structures among individuals with HIV. However, to our knowledge, no study has investigated subcortical shape alterations secondary to HIV and whether advancing age impacts that relationship. This study employed 3D morphometry to examine the independent and interactive effects of HIV and age on shape differences in nucleus accumbens, amygdala, caudate, hippocampus, pallidum, putamen, and thalamus in 81 participants ranging in age from 24 to 76 including 59 HIV+ individuals and 22 HIV-seronegative controls. T1-weighted MRI underwent a preprocessing pipeline followed by automated subcortical segmentation. Parametric statistical analyses were used to determine independent effects of HIV infection and age on volume and shape in each region of interest (ROI) and the interaction between age and HIV serostatus in predicting volume/shape in each ROI. Significant main effects for HIV were found in the shape of right caudate and nucleus accumbens, left pallidum, and hippocampus. Age was associated with differences in shape in left pallidum, right nucleus accumbens and putamen, and bilateral caudate, hippocampus, and thalamus. Of greatest interest, an age × HIV interaction effect was found in the shape of bilateral nucleus accumbens, amygdala, caudate, and thalamus as well as right pallidum and putamen such that increasing age in HIV participants was associated with greater shape alterations. Traditional volumemetric analyses revealed main effects for both HIV and age but no age × HIV interaction. These findings may suggest that age and HIV infection conferred additional deleterious effects on subcortical shape abnormalities beyond the independent effects of these factors. Hum Brain Mapp 38:1025-1037, 2017. © 2016 Wiley Periodicals, Inc.

Multilevel analysis of neuropathogenesis of neurocognitive impairment in HIV

The neuropathogenesis of HIV-associated neurocognitive disorders (HAND) remains puzzling. We interrogated several levels of data (host genetic, histopathology, brain viral load, and neurocognitive) to identify histopathological changes most relevant to HAND. The design of the study is a clinicopathological study employing genetic association analyses. Data and brain tissue from 80 HIV-infected adults were used. Markers in monocyte chemoattractant protein-1 (MCP-1), interleukin 1-alpha (IL1-α), macrophage inflammatory protein 1-alpha (MIP1-α), DRD3, DRD2, and apolipoprotein E (ApoE) were genotyped. Microtubule associated protein 2 (MAP2), synaptophysin (SYP), human leukocyte antigen-DR (HLA-DR), glial fibrillary acidic protein (GFAP), amyloid beta (A-Beta), and ionized calcium-binding adaptor molecule-1 (Iba-1) immunoreactivity were quantified in the frontal cortex, putamen, and hippocampus. A composite score for each marker (mean of the three brain regions) was used. Neurocognitive functioning and other clinical variables were determined within 1 year of death. Brain HIV RNA viral load was available for a subset of cases. MAP2 and SYP proved most relevant to neurocognitive functioning. Immunoreactivity of these markers, as well as A-Beta and Iba-1, was correlated with brain HIV RNA viral load. Several genetic markers in combination with other factors predicted histopathology: HIV blood viral load, MIP1-α genotype, and DRD3 genotype predicted Iba-1 immunoreactivity; the duration of infection and IL1-α genotype predicted GFAP immunoreactivity; ApoE genotype and age at death predicted A-Beta immunoreactivity. These data indicate that HIV replication in the brain is the primary driving force leading to neuroinflammation and dysfunctional protein clearance, as reflected by A-Beta and Iba-1. Downstream to these changes are synaptodendritic degeneration, which is the immediate histopathological substrate of the neurocognitive impairment characteristic of HAND. These intermediate histopathological phenotypes are influenced by host genetic polymorphisms in genes encoding cytokines/chemokines, neuronal protein clearance pathways, and dopaminergic factors.

Evidence informing the intersection of HIV, aging and health: a scoping review

The growing number of people over age 50 with HIV requires research, policy, and practice to develop a more comprehensive understanding of the health consequences of HIV in older individuals. We conducted a scoping review of peer-reviewed and grey literature published since 1996 to explore the impacts of aging on the health of older people with HIV (50 years or older). We included 209 studies (two systematic reviews, 174 quantitative studies, 28 qualitative studies, and five mixed methods studies). Health topics addressed include: HIV- and aging-related comorbidities, disease progression, neurocognitive functioning, mental health conditions, psychological well-being, social supports, stigma, antiretroviral adherence, health care utilization/access, and sexual risk behaviour. We recommend that future research takes a broader view of health, looks at aging from a strength-based perspective and examines the issue using diverse perspectives (i.e., geographic location, multiple methods, time of diagnosis, time on antiretroviral therapy (ART), demographic diversity).

Neuroprotective maraviroc monotherapy in simian immunodeficiency virus-infected macaques: reduced replicating and latent SIV in the brain

OBJECTIVE

HIV-associated neurocognitive deficits remain a challenge despite suppressive combined antiretroviral therapy. Given the association between HIV-induced central nervous system (CNS) disease and replication of HIV in immune-activated macrophages, CCR5 antagonists may attenuate CNS disease by modulating inflammatory signaling and by limiting viral replication.

DESIGN

To establish whether initiating CCR5 inhibition during early infection altered CNS disease progression, outcomes were compared between simian immunodeficiency virus (SIV)-infected macaques treated with maraviroc (MVC) versus untreated SIV-infected macaques.

METHODS

Six SIV-infected rhesus macaques were treated with MVC monotherapy for 5 months beginning 24 days postinoculation; 22 SIV-infected animals served as untreated controls. SIV RNA levels in plasma, cerobrospinal fluid, and brain, and CNS expression of TNFα and CCL2 were measured by qRT-PCR. Immunostaining for CD68 and amyloid precursor protein in the brain was measured by image analysis. Plasma sCD163 was measured by ELISA.

RESULTS

SIV RNA and proviral DNA levels in brain were markedly lower with MVC treatment, demonstrating CCR5 inhibition reduces CNS replication of SIV and may reduce the CNS latent viral reservoir. MVC treatment also lowered monocyte and macrophage activation, represented by CNS CD68 immunostaining and plasma sCD163 levels, and reduced both TNFα and CCL2 RNA expression in brain. Treatment also reduced axonal amyloid precursor protein immunostaining to levels present in uninfected animals, consistent with neuroprotection.

CONCLUSION

CCR5 inhibitors may prevent neurologic disorders in HIV-infected individuals by reducing inflammation and by limiting viral replication in the brain. Furthermore, CCR5 inhibitors may reduce the latent viral reservoir in the CNS. Adding CCR5 inhibitors to combined antiretroviral regimens may offer multiple neuroprotective benefits.

Isolating cognitive and neurologic HIV effects in substance-dependent, confounded cohorts: a pilot study

Controversy exists as to whether effects of HIV infection can be detected in the cognitive profiles of substance users, with methodological differences in degree of control for confounding factors a major contributor to empirical discrepancies. To address this shortcoming, we conducted a small but well-controlled study aimed at isolating HIV neurocognitive (NC) effects in a group of chronic substance users. Thirty HIV-negative substance users were individually matched to 30 HIV-positive substance users on relevant medical and demographic factors, including reading level and methadone therapy status. Results revealed that reading level, methadone maintenance therapy, and positive urine toxicology each exerted significant influence on NC function, and that HIV status was a significant predictor of learning and speeded processing after these control factors were considered. The HIV-positive group also displayed significantly more neurologically assessed motor impairment (p < .05), which was specifically related to impaired cognition in this group and independent of degree of immunocompromise. These data demonstrate the need for increased attention to clinical/demographic characteristics of groups under study. They also show that with applied methodological rigor, the deleterious effects of HIV on cognition can be parsed from substance use, even in small samples with chronic and active use histories.

Genome-wide association study of neurocognitive impairment and dementia in HIV-infected adults

The neuropathogenesis of HIV-associated neurocognitive disorders (HAND) is unclear. Candidate gene studies have implicated genetic susceptibility loci within immune-related genes; however, these have not been reliably validated. Here, we employed genome-wide association (GWA) methods to discover novel genetic susceptibility loci associated with HAND, and validate susceptibility loci implicated in prior candidate gene studies. Data from 1,287 participants enrolled in the Multicenter AIDS Cohort Study between 1985 and 2010 were used. Genotyping was conducted with Illumina 1M, 1MDuo, or 550K platform. Linear mixed models determined subject-specific slopes for change over time in processing speed and executive functioning, considering all visits including baseline and the most recent study visit. Covariates modeled as fixed effects included: time since the first visit, depression severity, nadir CD4+ T-cell count, hepatitis C co-infection, substance use, and antiretroviral medication regimen. Prevalence of HIV-associated dementia (HAD) and neurocognitive impairment (NCI) was also examined as neurocognitive phenotypes in a case-control analysis. No genetic susceptibility loci were associated with decline in processing speed or executive functioning among almost 2.5 million single nucleotide polymorphisms (SNPs) directly genotyped or imputed. No association between the SNPs and HAD or NCI were found. Previously reported associations between specific genetic susceptibility loci, HIV-associated NCI, and HAD were not validated. In this first GWAS of HAND, no novel or previously identified genetic susceptibility loci were associated with any of the phenotypes examined. Due to the relatively small sample size, future collaborative efforts that incorporate this dataset may still yield important findings.

Regional brain structural dysmorphology in human immunodeficiency virus infection: effects of acquired immune deficiency syndrome, alcoholism, and age

BACKGROUND

Human immunodeficiency virus (HIV) infection and alcoholism each carries liability for disruption of brain structure and function integrity. Despite considerable prevalence of HIV-alcoholism comorbidity, few studies examined the potentially heightened burden of disease comorbidity.

METHODS

Participants were 342 men and women: 110 alcoholics, 59 with HIV infection, 65 with HIV infection and alcoholism, and 108 healthy control subjects. This design enabled examination of independent and combined effects of HIV infection and alcoholism along with other factors (acquired immune deficiency syndrome [AIDS]-defining events, hepatitis C infection, age) on regional brain volumes derived from T1-weighted magnetic resonance images.

RESULTS

Brain volumes, expressed as Z scores corrected for intracranial volume and age, were measured in 20 tissue and 5 ventricular and sulcal regions. The most profound and consistent volume deficits occurred with alcohol use disorders, notable in the cortical mantle, insular and anterior cingulate cortices, thalamus, corpus callosum, and frontal sulci. The HIV-only group had smaller thalamic and larger frontal sulcal volumes than control subjects. HIV disease-related factors associated with greater volume abnormalities included CD4 cell count nadir, clinical staging, history of AIDS-defining events, infection age, and current age. Longer sobriety and less lifetime alcohol consumption were predictive of attenuated brain volume abnormalities in both alcohol groups.

CONCLUSIONS

Having HIV infection with alcoholism and AIDS had an especially poor outcome on brain structures. That longer periods of sobriety and less lifetime alcohol consumption were predictive of attenuated brain volume abnormalities encourages the inclusion of alcohol recovery efforts in HIV/AIDS therapeutic settings.

"It's a hidden issue": exploring the experiences of women with HIV-associated neurocognitive challenges using a disability framework

PURPOSE

To use the World Health Organization's International Classification of Functioning, Disability and Health (ICF) to explore the experiences of women living with self-identified HIV-associated neurocognitive challenges.

METHOD

This interpretive, qualitative study involved key informant interviews with 16 women with self-identified HIV-associated neurocognitive challenges. Data were collected through 60-90 min, in-depth, semi-structured interviews. Thematic analysis was performed using an inductive approach. Theoretical analysis then used the ICF to reconceptualize the data using a disability lens.

RESULTS

Participants perceived impairments (e.g. memory loss, difficulty multi-tasking) and participation restrictions (e.g. parenting, work roles) resulting from their neurocognitive challenges as having a larger impact on their daily lives than activity limitations (e.g. difficulty with chores). Participants held contrasting views about parenting: women with children drew strength from parenting whereas women without children worried that parenting could compromise their health. Participation in work and volunteering roles was viewed as integral to managing neurocognitive challenges and health overall.

CONCLUSIONS

Conceptualizing neurocognitive challenges through a disability lens focuses attention on how impairments interact with other realities in these women's lives. This exploratory study reveals the need for future research exploring perceptions among people living with HIV-associated neurocognitive challenges with attention to aging and among other vulnerable groups.

Neurotoxic effects of the HCV core protein are mediated by sustained activation of ERK via TLR2 signaling

Hepatitis C virus (HCV) infection is a serious problem among those co-infected with human immunodeficiency virus; however, its impact in the central nervous system (CNS) remains unclear. This study aimed to investigate the mechanisms underlying HCV core protein-mediated neurodegeneration. Analysis of human HCV seropositive cases demonstrated widespread damage to neuronal dendritic processes and sustained activation of extracellular signal-related kinase (ERK); analogous pathologies were observed in wild type injected with HCV core protein into the hippocampus. In vitro analysis in neuronal cells exposed to HCV core demonstrated retraction of the neuronal processes in an ERK/Signal Transducer and Activator of Transcription 3 (STAT3)-dependent manner dependent on toll-like receptor 2 (TLR2) signaling activation. These results indicate that HCV core protein neurotoxicity may be mediated by the sustained activation of ERK/STAT3 via TLR2-IRAK1 signaling pathway. These pathways provide novel targets for development of neuroprotective treatments for HCV involvement of the CNS.

Impact of HIV and a history of marijuana dependence on procedural learning among individuals with a history of substance dependence

Marijuana (MJ) use and HIV infection are both associated with neurocognitive deficits, yet there is little research to date examining their interactions, specifically how they pertain to procedural learning (PL). We examined a sample of 86 individuals with a history of dependence for multiple substances who underwent a comprehensive evaluation including measures of mental health, substance use history, and three measures of PL: the photoelectric Rotary Pursuit Task (RPT), the Star Mirror Tracing Task (SMT), and the Weather Prediction Task (WPT). We found that a positive HIV serostatus and a history of marijuana dependence were both independently associated with overall poorer performance on the SMT and RPT in this sample of individuals with a history of dependence for multiple substances. Rate of improvement across trial blocks did not differ as a function of HIV serostatus or history of marijuana dependence. Although we found no significant HIV × MJ interaction for any of the PL tasks, we did observe evidence of additive negative effects from HIV and a history of marijuana dependence on overall performance on the SMT and RPT, but not the WPT. The findings suggest that complex motor skills are adversely affected among abstinent polysubstance users with a history of marijuana dependence and that such deficits are compounded by HIV.

Symptom disclosure by older HIV-infected persons

The life expectancy for persons living with HIV infection is markedly increasing, largely because of the advances made with antiretroviral therapy. In comparison with other older individuals, those infected with HIV tend to have higher rates of liver-related conditions, diabetes, and dyslipidemia, as well as substance use and psychiatric disorders. Although these multimorbidities contribute to the symptom burden, older persons with HIV tend not to disclose symptoms to their health care providers. Culture, religion, age, and race can profoundly affect the way in which symptoms are perceived, and reasons for nondisclosure include attributing symptoms to the "normal" aging process. The purpose of this article is to highlight the unique situation of older patients with HIV regarding symptom disclosure and the need for an integrated treatment plan that includes an environment that promotes patient-provider communication, better day-to-day self-care, and self-management strategies.

Prescription use disorders in older adults

The number of older adults needing substance abuse treatment is projected to rise significantly in the next few decades. This paper will focus on the epidemic of prescription use disorders in older adults. Particular vulnerabilities of older adults to addiction will be considered. Specifically, the prevalence and patterns of use of opioids, stimulants, and benzodiazepines will be explored, including the effects of these substances on morbidity and mortality. Treatment intervention strategies will be briefly discussed, and areas for future research are suggested.

HIV+ men and women show different performance patterns on procedural learning tasks

The literature suggests that nondeclarative, or nonconscious, learning might be impaired among HIV-seropositive (HIV+) individuals compared with HIV-seronegative (HIV-) matched control groups, but these studies have included relatively few women. We administered measures of motor skill and probabilistic learning, tasks with a nondeclarative or procedural learning component that are dependent on integrity of prefrontal-striatal systems, to well-matched groups of 148 men and 65 women with a history of substance dependence that included 45 men and 30 women seropositive for HIV. All participants were abstinent at testing. Compared to HIV- women, HIV+ women performed significantly more poorly on both tasks, but HIV+ men's performance did not differ significantly from that of HIV- men on either task. These different patterns of performance indicate that features of HIV-associated neurocognitive disorder (HAND) cannot always be generalized from men to women. Additional studies are needed to address directly the possibility of sex differences in HAND and the possibility that women might be more vulnerable to the effects of HIV and substance dependence on some neurocognitive functions.

Iowa Gambling Task performance and emotional distress interact to predict risky sexual behavior in individuals with dual substance and HIV diagnoses

HIV+ substance-dependent individuals (SDIs) show emotional distress and executive impairment, but in isolation these poorly predict sexual risk. We hypothesized that an executive measure sensitive to emotional aspects of judgment (Iowa Gambling Task; IGT) would identify HIV+ SDIs whose sexual risks were influenced by emotional distress. We assessed emotional distress and performance on several executive tasks in 190 HIV+ SDIs. IGT performance interacted significantly with emotional distress, such that only in better performers were distress and risk related. Our results are interpreted using the somatic marker hypothesis and indicate that the IGT identifies HIV+ SDIs for whom psychological distress influences HIV risk.

Influence of procedural learning on Iowa Gambling Task performance among HIV+ individuals with history of substance dependence

HIV+ individuals have been shown to demonstrate deficits on the Iowa Gambling Task (IGT), a complex measure of "decision-making." Little remains known about what other neurocognitive processes may account for variability in IGT performance among HIV+ samples or the role of procedural learning (PL) in IGT performance. A sample of 49 HIV+ individuals with a history of substance use disorders was examined to explore the relationship between IGT performance and three measures of PL: The Rotary Pursuit, Mirror Star Tracing, and Weather Prediction tasks. We found no statistically significant relationships between IGT performance and any of the PL tasks, despite finding significant correlations among the PL tasks. This pattern of results persisted when analyzing IGT performance in various ways (e.g., performance on earlier trial blocks or impairment classifications). Although other nondeclarative processes (e.g., somatic markers) may be important for IGT performance, these findings do not support PL as an important component neurocognitive process for the IGT. Similarly, these results suggest that differences in PL performance does not account for the decision-making deficits or variability in performances observed on the IGT among HIV+ individuals with a history of substance dependence.