Biomarkers and neurodevelopment in perinatally HIV-infected or exposed youth: a structural equation model analysis

Pro-inflammatory and anti-inflammatory immune biomarkers as predictors of neurodevelopment in young children exposed to HIV

OBJECTIVE

Higher inflammation and lower neurodevelopmental outcomes have been reported in children exposed to HIV but uninfected (CHEU) compared to children unexposed to HIV (CHU) during infancy, but whether these differences persist in early childhood is unclear. We assessed pro-inflammatory and anti-inflammatory biomarkers and their associations with neurodevelopmental outcomes in CHEU and CHU aged 18-36 months.

DESIGN

Cross-sectional study of 45 CHEU and 36 CHU aged 18-36 months enrolled in Eldoret, Kenya.

METHODS

Plasma levels of 65 cytokines, chemokines, growth factors, and soluble receptors, and 16 soluble immune checkpoints (ICPs) were quantified using multiplex immunoassays. Monocyte activation (sCD14, sCD163) and endothelial activation (CD146, ICAM-1, VCAM-1) plasma levels were measured by ELISAs. Neurodevelopmental outcomes were assessed using the culturally adapted developmental assessment of cognition, language, and motor function. Predictors of neurodevelopmental outcomes were assessed using Bayesian Model Averaging of the linear regression model.

RESULTS

CHEU exhibited lower levels of several chemokine and growth factors and four inflammatory cytokines compared to CHU: A proliferation inducing ligand (APRIL) ( P  = 0.03), IL-12p70 ( P  < 0.001), macrophage migration inhibitory factor (MIF) ( P  = 0.002), and Tweak ( P  = 0.003). Conversely, two soluble ICPs, CD40 ( P  = 0.02) and TIM3 ( P  = 0.001), were higher in CHEU compared to CHU. IL-22 and SDF-1α emerged as the strongest predictors of neurodevelopment in CHEU and CHU, respectively.

CONCLUSION

In early childhood, CHEU exhibited an immunosuppressive rather than inflammatory biomarker profile. Immune biomarkers more frequently predicted neurodevelopmental outcomes than social and demographic factors, and the predictors of cognitive, motor, and language outcomes differed between CHU and CHEU. Further research is necessary to explore the connection between childhood neurodevelopment and immune biomarkers.

Plasma galectin-9 relates to cognitive performance and inflammation among adolescents with vertically acquired HIV

OBJECTIVE

Adolescents with perinatally acquired HIV (AWH) are at an increased risk of poor cognitive development yet the underlying mechanisms remain unclear. Circulating galectin-9 (Gal-9) has been associated with increased inflammation and multimorbidity in adults with HIV despite antiretroviral therapy (ART); however, the relationship between Gal-9 in AWH and cognition remain unexplored.

DESIGN

A cross-sectional study of two independent age-matched cohorts from India [AWH on ART ( n  = 15), ART-naive ( n  = 15), and adolescents without HIV (AWOH; n  = 10)] and Myanmar [AWH on ART ( n  = 54) and AWOH ( n  = 22)] were studied. Adolescents from Myanmar underwent standardized cognitive tests.

METHODS

Plasma Gal-9 and soluble mediators were measured by immunoassays and cellular immune markers by flow cytometry. We used Mann-Whitney U tests to determine group-wise differences, Spearman's correlation for associations and machine learning to identify a classifier of cognitive status (impaired vs. unimpaired) built from clinical (age, sex, HIV status) and immunological markers.

RESULTS

Gal-9 levels were elevated in ART-treated AWH compared with AWOH in both cohorts (all P  < 0.05). Higher Gal-9 in AWH correlated with increased levels of inflammatory mediators (sCD14, TNFα, MCP-1, IP-10, IL-10) and activated CD8 + T cells (all P  < 0.05). Irrespective of HIV status, higher Gal-9 levels correlated with lower cognitive test scores in multiple domains [verbal learning, visuospatial learning, memory, motor skills (all P  < 0.05)]. ML classification identified Gal-9, CTLA-4, HVEM, and TIM-3 as significant predictors of cognitive deficits in adolescents [mean area under the curve (AUC) = 0.837].

CONCLUSION

Our results highlight a potential role of Gal-9 as a biomarker of inflammation and cognitive health among adolescents with perinatally acquired HIV.

Cognitive impairment in children and adolescents living with perinatal HIV disease in the ART era: a meta-analysis

Background

Despite improved survival and overall health outcomes from modern antiretroviral therapy (ART), children and adolescents living with HIV are facing pervasive impairments in neurodevelopment including cognitive impairment, but there remains a lack of consensus on the cognitive domains that are affected in those children and adolescents. The objective of this meta-analysis was to evaluate the impact of perinatal HIV-infection on executive function, working memory, and speed of information processing in the ART era.

Methods

The PubMed database was searched for studies published between 1997 and 2024, plus additional search with the ScienceDirect, bioRxiv, and medRxiv databases. A meta-analysis was conducted on thirty-five studies published between 2012 and 2023 that encompassed a total of 4066 perinatally-infected HIV patients, 2349 HIV-exposed uninfected (HEU) controls, and 2466 HIV-unexposed, uninfected (HUU) controls. Performance scores on executive function, working memory, and processing speed were pooled using random-effects meta-analysis.

Findings

Compared to HEU and HUU controls, perinatally HIV-infected children and adolescents presented with significant impairments in processing speed (Hedges g = -0.64, p < 0.00001), working memory (Hedges g = -0.69, p < 0.00001), and to a lesser degree, executive function (Hedges g = -0.35, p = 0.02). Meta-regression analysis suggested that the effect estimate of processing speed impairment negatively correlated with Gross National Income (GNI) per capita of the study countries (CALHIV vs HUU, p = 0.0016; CALHIV vs HEU, p = 0.0019), even though HIV-infected cases were compared to sociodemographically matched HUU controls from the same countries. Sub-group meta-analyses with participants from high-income or low-/middle-income countries provided further evidence suggesting that the performance gap between HIV-infected cases and HUU/HEU controls may be larger in low-/middle-income countries than high-income countries.

Interpretation

In the ART era, cognitive impairment (especially reduced processing speed and working memory) persists in children and adolescents living with HIV. These impairments may be more pronounced among those children and adolescents living with HIV in low-income countries, suggesting that there may be global health inequities in treatment outcomes with perinatal HIV-infection. However, meta-analysis and meta-regression analysis have their limitations, which calls for future collaborative multi-country international studies to directly investigate this important topic. Nevertheless, there is an unmet need to assure equity in timely assessments and interventions to optimize neurocognitive development and outcomes among children and adolescents with perinatal HIV globally.

Funding

This research was supported in part by NIH R01MH108466, NIH R56NS124422, and NIH R01NS124422.

Influence of HIV infection on cognition and overall intelligence in HIV-infected individuals: advances and perspectives

It is now well understood that HIV-positive individuals, even those under effective ART, tend to develop a spectrum of cognitive, motor, and/or mood conditions which are contemporarily referred to as HIV-associated neurocognitive disorder (HAND), and which is directly related to HIV-1 infection and HIV-1 replication in the central nervous system (CNS). As HAND is known to induce difficulties associated with attention, concentration, and memory, it is thus legitimate and pertinent to speculate upon the possibility that HIV infection may well influence human cognition and intelligence. We therefore propose herein to review the concept of intelligence, the concept of cells of intelligence, the influence of HIV on these particular cells, and the evidence pointing to differences in observed intelligence quotient (IQ) scores between HIV-positive and HIV-negative individuals. Additionally, cumulative research evidence continues to draw attention to the influence of the gut on human intelligence. Up to now, although it is known that HIV infection profoundly alters both the composition and diversity of the gut microbiota and the structural integrity of the gut, the influence of the gut on intelligence in the context of HIV infection remains poorly described. As such, we also provide herein a review of the different ways in which HIV may influence human intelligence via the gut-brain axis. Finally, we provide a discourse on perspectives related to HIV and human intelligence which may assist in generating more robust evidence with respect to this issue in future studies. Our aim is to provide insightful knowledge for the identification of novel areas of investigation, in order to reveal and explain some of the enigmas related to HIV infection.

Longitudinal Cognitive Outcomes in Children With HIV in Zambia: 2-Year Outcomes From the HIV-Associated Neurocognitive Disorders in Zambia (HANDZ) Study

OBJECTIVE

To describe longitudinal outcomes and predictors of cognitive outcomes in children with HIV in Zambia.

BACKGROUND

Multiple studies have shown that children with HIV are at risk for impaired cognition. However, there are limited data on longitudinal cognitive outcomes in children with HIV.

METHODS

We conducted a prospective cohort study of 208 perinatally infected children with HIV ages 8-17 years, all treated with antiretroviral therapy, and 208 HIV-exposed uninfected controls. Participants were followed for 2 years. Cognition was assessed with a custom NIH Toolbox Cognition Battery, and tests were combined to generate a Summary Cognition Score (SCS). The contribution of potential risk factors to outcomes was explored using regression models and group-based trajectory modeling.

RESULTS

HIV was strongly associated with lower SCS at baseline [β-14, 95% confidence interval (CI): -20 to -7, P < 0.001]. Change scores over time were similar between groups, but poorer average performance in children with HIV persisted at the 2-year follow-up visit (adjusted β = -11, 95% CI: -22 to -0.3, P = 0.04). Other than HIV, the strongest predictors of baseline SCS included socioeconomic status index (β =3, 95% CI: 1, 5, P = 0.004), history of growth stunting (β=-14, 95% CI: -23 to -6, P = 0.001), history of CD4 count below 200 (β = -19, 95% CI: -35 to -2, P = 0.02), and history of World Health Organization stage 4 disease (β = -10, 95% CI: -19 to -0.2, P = 0.04). In the group-based trajectory model, HIV+ status predicted membership in the lowest performing trajectory group (odds ratio 2.5, 95% CI: 1.2 to 5.1, P = 0.01).

CONCLUSIONS

Children with HIV are at risk of poor cognitive outcomes, despite chronic treatment with antiretroviral therapy.

The association between mental health and metabolic outcomes in youth living with perinatally acquired HIV in the Cape Town Adolescent Antiretroviral Cohort

Youth living with perinatally acquired HIV (YLPHIV) have been found to have a range of mental disorders. Some adult HIV studies have linked mental health to adverse metabolic outcomes due to dysregulation of the sympathetic nervous system and hypothalamic-pituitary-adrenal axis, but this association has not previously been explored in YLPHIV.We investigated the association of mental health measures with metabolic outcomes in YLPHIV and HIV-uninfected youth (HIV-U) and linear regression was used to assess the adjusted associations.Overall, 203 YLPHIV (median age = 10.7years; 52% female; mean duration on ART 8 years, 12% CD4 count <500 cells/µL, 18% viral load >50 copies/mL) and 44 HIV-U (median age = 10.3 years; 55% female) were enrolled. YLPHIV had higher median total cholesterol (4.2 vs 3.9 mmol/L, p = 0.049) and triglyceride (0.9 vs 0.7 mmol/L, p < 0.001) compared to HIV-U. We found higher percentage of poor functional competence (40% vs 25%, p = 0.02) and self-concept (23% vs 9%, p = 0.03) and higher depression (6% vs 2%, p < 0.01), anger (6% vs 2%, p = 0.04) and disruptive behaviour (4% vs 0%, p < 0.01) in YLPHIV as compared to HIV-U. Among YLPHIV, higher scores of anger were associated with higher total cholesterol and higher low-density lipoprotein (ß = 0.010, p = 0.041 and ß = 0.012, p = 0.048 respectively) and disruptive behaviour with higher low-density lipoprotein (ß = 0.010, p = 0.043) after adjusting for age, sex and BMIZ.This is the one of first study to investigate the association of mental health with metabolic outcomes among YLPHIV. The association of increased anger and disruptive behaviour with increased lipid concentration is a novel finding. Further longitudinal studies are needed to evaluate the causal relationships between mental health and metabolic outcomes.

Biomarkers of Oxidative Stress Tethered to Cardiovascular Diseases

Cardiovascular disease (CVD) is a broad term that incorporated a group of conditions that affect the blood vessels and the heart. CVD is a foremost cause of fatalities around the world. Multiple pathophysiological mechanisms are involved in CVD; however, oxidative stress plays a vital role in generating reactive oxygen species (ROS). Oxidative stress occurs when the concentration of oxidants exceeds the potency of antioxidants within the body while producing reactive nitrogen species (RNS). ROS generated by oxidative stress disrupts cell signaling, DNA damage, lipids, and proteins, thereby resulting in inflammation and apoptosis. Mitochondria is the primary source of ROS production within cells. Increased ROS production reduces nitric oxide (NO) bioavailability, which elevates vasoconstriction within the arteries and contributes to the development of hypertension. ROS production has also been linked to the development of atherosclerotic plaque. Antioxidants can decrease oxidative stress in the body; however, various therapeutic drugs have been designed to treat oxidative stress damage due to CVD. The present review provides a detailed narrative of the oxidative stress and ROS generation with a primary focus on the oxidative stress biomarker and its association with CVD. We have also discussed the complex relationship between inflammation and endothelial dysfunction in CVD as well as oxidative stress-induced obesity in CVD. Finally, we discussed the role of antioxidants in reducing oxidative stress in CVD.

Socioeconomic Status and Cognitive Function in Children With HIV: Evidence From the HIV-Associated Neurocognitive Disorders in Zambia (HANDZ) Study

BACKGROUND

Multiple previous studies have identified a detrimental effect of pediatric HIV on cognitive function. Socioeconomic status (SES) is one of the strongest predictors of cognitive performance and may affect the relationship between HIV and cognition.

METHODS

As part of the ongoing HIV-Associated Neurocognitive Disorders in Zambia (HANDZ) study, a prospective cohort study, we recruited 208 participants with HIV and 208 HIV-exposed uninfected controls, all aged 8-17 years. A standardized questionnaire was administered to assess SES, and all participants had comprehensive neuropsychological testing. An NPZ8 score was derived as a summary measure of cognitive function. Logistic regression and linear regression were used to model the relationship between SES and cognitive function, and mediation analysis was used to identify specific pathways by which SES may affect cognition.

RESULTS

Children with HIV performed significantly worse on a composite measure of cognitive function (NPZ8 score -0.19 vs. 0.22, P < 0.001) and were more likely to have cognitive impairment (33% vs. 19%, P = 0.001). Higher SES was associated with reduced risk of cognitive impairment (odds ratio 0.8, 95% confidence interval: 0.75-0.92, P < 0.001) in both groups, with similar effects in children with HIV and HIV-exposed uninfected groups. SES was more strongly correlated with NPZ8 score in children with HIV than in uninfected controls (Pearson's R 0.39 vs. 0.28), but predicted NPZ8 in both groups. Mediation analysis suggested that the effect of SES on cognition was most strongly mediated through malnutrition.

CONCLUSIONS

Cognitive function is strongly correlated with SES in children with HIV, suggesting a synergistic effect of HIV and poverty on cognitive function.

Immune Dysregulation Is Associated with Neurodevelopment and Neurocognitive Performance in HIV Pediatric Populations-A Scoping Review

HIV-1 is known for its complex interaction with the dysregulated immune system and is responsible for the development of neurocognitive deficits and neurodevelopmental delays in pediatric HIV populations. Considering that HIV-1-induced immune dysregulation and its association with neurodevelopmental and neurocognitive impairments in pediatric populations are not well understood, we conducted a scoping review on this topic. The study aimed to systematically review the association of blood and cerebrospinal fluid (CSF) immune markers with neurocognitive deficits and neurodevelopmental delays in pediatric HIV populations. PubMed, Scopus, and Web of Science databases were searched using a search protocol designed specifically for this study. Studies were selected based on a set eligibility criterion. Titles, abstracts, and full texts were assessed by two independent reviewers. Data from the selected studies were extracted and analyzed by two independent reviewers. Seven studies were considered eligible for use in this context, which included four cross-sectional and three longitudinal studies. An average of 130 (±70.61) children living with HIV, 138 (±65.37) children exposed to HIV but uninfected and 90 (±86.66) HIV-negative participants were included across the seven studies. Results indicate that blood and CSF immune markers are associated with neurocognitive development/performance in pediatric HIV populations. Only seven studies met the inclusion criteria, therefore, these limited the number of significant conclusions which could have been made by using such an approach. All considered, the evidence suggests that immune dysregulation, as in the case of adult HIV populations, also has a significant association with neurocognitive performance in pediatric HIV populations.

Parenteral artemisinins are associated with reduced mortality and neurologic deficits and improved long-term behavioral outcomes in children with severe malaria

BACKGROUND

In 2011, the World Health Organization recommended injectable artesunate as the first-line therapy for severe malaria (SM) due to its superiority in reducing mortality compared to quinine. There are limited data on long-term clinical and neurobehavioral outcomes after artemisinin use for treatment of SM.

METHODS

From 2008 to 2013, 502 Ugandan children with two common forms of SM, cerebral malaria and severe malarial anemia, were enrolled in a prospective observational study assessing long-term neurobehavioral and cognitive outcomes following SM. Children were evaluated a week after hospital discharge, and 6, 12, and 24 months of follow-up, and returned to hospital for any illness. In this study, we evaluated the impact of artemisinin derivatives on survival, post-discharge hospital readmission or death, and neurocognitive and behavioral outcomes over 2 years of follow-up.

RESULTS

346 children received quinine and 156 received parenteral artemisinin therapy (artemether or artesunate). After adjustment for disease severity, artemisinin derivatives were associated with a 78% reduction in in-hospital mortality (adjusted odds ratio, 0.22; 95% CI, 0.07-0.67). Among cerebral malaria survivors, children treated with artemisinin derivatives also had reduced neurologic deficits at discharge (quinine, 41.7%; artemisinin derivatives, 23.7%, p=0.007). Over a 2-year follow-up, artemisinin derivatives as compared to quinine were associated with better adjusted scores (negative scores better) in internalizing behavior and executive function in children irrespective of the age at severe malaria episode. After adjusting for multiple comparisons, artemisinin derivatives were associated with better adjusted scores in behavior and executive function in children <6 years of age at severe malaria exposure following adjustment for child age, sex, socioeconomic status, enrichment in the home environment, and the incidence of hospitalizations over follow-up. Children receiving artesunate had the greatest reduction in mortality and benefit in behavioral outcomes and had reduced inflammation at 1-month follow-up compared to children treated with quinine.

CONCLUSIONS

Treatment of severe malaria with artemisinin derivatives, particularly artesunate, results in reduced in-hospital mortality and neurologic deficits in children of all ages, reduced inflammation following recovery, and better long-term behavioral outcomes. These findings suggest artesunate has long-term beneficial effects in children surviving severe malaria.

Plasma biomarker factors associated with neurodevelopmental outcomes in children with perinatal HIV infection and controlled viremia

OBJECTIVE

We examined relationships between plasma biomarkers and neurodevelopment in children from sub-Saharan Africa with perinatal HIV (PHIV) with controlled viremia on antiretroviral therapy (ART).

DESIGN

Longitudinal retrospective cohort study of children with controlled blood HIV replication.

METHODS

Children (N = 213; 57% girls) started ART at less than 3 years of age, had neurodevelopmental assessments (cognition, attention/impulsivity, motor proficiency, global executive functions) at 5-11 years, and achieved controlled viremia (HIV-1 RNA <400 copies/ml for ≥9 months before initial assessment). Twenty-three plasma biomarkers were measured at onset of controlled viremia, week 0 (first neurodevelopmental assessment), and week 48 (second neurodevelopmental assessment). Factor analysis was conducted at each time point. Multivariable linear regressions assessed associations between factors and neurodevelopmental scores.

RESULTS

Median age at week 0 was 7.0 years. Eighteen biomarkers loaded on six factors: a (L-10, IFNγ, IFNα2, IL-1β, IL-6, IP-10, TNFα); B (sCD163, sICAM-1, sVCAM-1, CRP); C (sE-selectin, sP-selectin); D [MIP-1β, vascular endothelial growth factor (VEGF)-A]; E (sCD14, CRP); and F (CX3CL1, MCP-1). Higher factor B scores were consistently associated with worse cognition and attention/impulsivity, and higher factor D scores with better attention/impulsivity.

CONCLUSION

These results suggest a detrimental effect of increased endothelial cell activation (sICAM-1, sVCAM-1) and monocyte/macrophage scavenger function (sCD163) and a beneficial effect of increased CCR5 ligand and HIV entry blocker MIP-1β and angiogenesis stimulant-VEGF concentrations on the neurodevelopment of children with PHIV. The model that emerges is of vascular inflammation leading to neurodevelopmental deficits. The role of persistent HIV replication in the central nervous system also needs to be further explored.

Executive function in HIV-affected children and adolescents: a systematic review and meta-analyses

This review aimed to determine: whether EF is affected in children and adolescents (2-24-years-old) with perinatal HIV infection, perinatal HIV exposure without infection, and behaviourally acquired HIV. A systematic review (PROSPERO number: CRD42017067813) was conducted using 11 electronic databases (01.01.1981-09.07.2019) and 8 conference websites. Primary quantitative studies with EF scores on cognitive tasks and/or behavioural report measures were included. Meta-analyses were performed by EF subtype and subpopulations compared. 1789 records were found. Sixty-one studies were included in the narrative synthesis; 32 (N = 7884 participants) were included in meta-analyses. There was a distinct pattern of reduced EF in those with perinatal HIV infection on antiretroviral therapy compared to controls: pooled effect sizes were largest for verbal and visuospatial working memory, with smaller effects on planning, inhibitory control and set-shifting. Data were limited for other HIV-affected subpopulations. Perinatal HIV infection is associated with reduced EF with varying effect sizes for the different EF subtypes.

Behavioral and Physical Activity Interventions for HAND

Approximately 30-50% of persons living with HIV manifest some degree of neurocognitive impairment. Even mild-to-moderate forms of HIV-associated neurocognitive disorders (HAND) can result in difficulties with everyday functioning, such as suboptimal medication adherence and impaired driving. Despite the pervasive presence and consequences of HAND, there is a significant unmet need to develop effective behavioral strategies to reduce the incidence and consequences of HAND. Although there is an absence of evidence-based behavioral interventions specific to HAND, the literature reviewed in this chapter suggest the following modifiable lifestyle factors as intervention targets: physical activity, diet, sleep, and antiretroviral medication adherence. Adoption and maintenance of these healthy lifestyle factors may reduce inflammation and oxidative stress, which, in turn, may reduce the incidence and/or severity of HAND.

Higher soluble CD14 levels are associated with lower visuospatial memory performance in youth with HIV

OBJECTIVE

HIV-associated neurocognitive disorders persist despite early antiretroviral therapy (ART) and optimal viral suppression. We examined the relationship between immunopathogenesis driven by various pathways of immune activation and discrete neurocognitive performance domains in youth with HIV (YWH).

DESIGN

Observational cross-sectional study.

METHODS

YWH, ages 20-28 years, enrolled in Adolescent Medicine Trials Network 071/101 were assessed for biomarkers of macrophage, lymphocyte activation, and vascular inflammation using ELISA/multiplex assays. Standardized neurocognitive tests were performed, and demographically adjusted z-scores were combined to form indices of attention, motor, executive function, verbal, and visuospatial memory. Cross-sectional analysis of the relationship between 18 plasma inflammatory biomarkers and each neurocognitive domain was performed. Linear regression models were fit for each combination of log-transformed biomarker value and neurocognitive domain score, and were adjusted for demographics, socioeconomic status, substance use, depression, CD4 T-cell count, HIV viral load, and ART status.

RESULTS

Study included 128 YWH [mean age 23.8 (SD 1.7) years, 86% men, 68% African American]. Verbal and visuospatial memory domains were most significantly impaired in the cohort (z = -1.59 and -1.0, respectively). Higher sCD14 was associated with impaired visuospatial memory, which remained robust after adjusting for other biomarkers, demographics, and HIV-associated covariates. Among biomarkers of vascular inflammation, sICAM-1 was negatively associated with verbal memory and attention, whereas sVCAM-1 was positively associated with executive function and visuospatial memory. Specific neurocognitive domains were not associated with sCD163, LPS, or CCL2 levels.

CONCLUSION

Impaired visuospatial memory in YWH is associated with immune activation, as reflected by higher sCD14.

Neurocognitive dysfunction in HIV-infected youth: investigating the relationship with immune activation

BACKGROUND

HIV-infected individuals are at increased risk of neurocognitive impairment compared to the general population. Studies suggest that, despite combination antiretroviral therapy (cART), HIV infection causes immune activation which results in neural damage; however, few data exist in HIV-infected youth.

METHODS

HIV-infected youth 8-26-years-old on cART with virological suppression were prospectively enrolled along with healthy controls. Neurocognitive performance was assessed by age-appropriate Wechsler Intelligence Scales. Soluble and cellular markers of T-lymphocyte and monocyte activation were measured by ELISA and flow cytometry, respectively.

RESULTS

45 HIV-infected subjects and 21 controls were enrolled. Markers of T-cell and monocyte activation were higher in the HIV-infected subjects compared to controls, but proportions of inflammatory and patrolling monocytes were similar. Although there were no significant differences in neurocognitive scores between the HIV-infected and control groups, scores were low-average for four of five testing domains for the HIV-infected subjects and average for all five in the controls, and % of HIV-infected subjects with scores classified as 'low average' or below was higher than in the controls. Variables most associated with neurocognitive performance among HIV-infected subjects included activated CD4⁺ T-cells (% CD4+CD38+HLA-DR), monocyte activation (soluble CD14), HIV duration, age and sex.

CONCLUSIONS

HIV-infected youth on cART with virological suppression show subtle evidence of neurocognitive impairment compared to healthy controls, and increased immune activation appears to play a role. Additional studies are needed to develop strategic interventions beyond cART to potentially improve neurocognitive performance and/or minimize further impairment in this vulnerable population. ClinicalTrials.gov Identifier: NCT01523496.

CNS Persistence of HIV-1 in Children: the Untapped Reservoir

PURPOSE OF REVIEW

The central nervous system (CNS) represents a potential HIV-1 reservoir that may need to be specifically targeted by remission strategies. Perinatally HIV-1-infected children and youth are exposed to HIV-1 at a critical period of brain development. This review summarizes the current literature regarding HIV-1 and the CNS in perinatal infection.

RECENT FINDINGS

HIV-1-associated encephalopathy is prevalent with perinatal infection and neurocognitive impairment persists even following antiretroviral treatment (ART)-mediated suppression of viremia. Compartmentalization of HIV-1 between plasma and CSF of ART-naïve, perinatally infected children suggests the presence of a CNS reservoir; however, similar studies have not yet been conducted with ART suppression. CSF viral escape where CSF and plasma virus concentrations are discordant has been reported in this population, but larger studies with well-defined virologic and immunologic parameters are needed. A better understanding of HIV-1 persistence in the CNS with perinatal infection is essential for improving long-term neurocognitive outcomes and for designing strategies to induce HIV-1 remission in this population.

Systemic and intrathecal immune activation in association with cerebral and cognitive outcomes in paediatric HIV

Despite treatment, immune activation is thought to contribute to cerebral injury in children perinatally infected with human immunodeficiency virus (HIV). We aimed to characterize immune activation in relation to neuroimaging and cognitive outcomes. We therefore measured immunological, coagulation, and neuronal biomarkers in plasma and cerebrospinal fluid (CSF) samples of 34 perinatally HIV-infected children aged 8–18 years, and in plasma samples of 37 controls of comparable age, sex, ethnicity, and socio-economic status. We then compared plasma biomarker levels between groups, and explored associations between plasma/CSF biomarkers and neuroimaging and cognitive outcomes using network analysis. HIV-infected children showed higher plasma levels of C-reactive protein, interferon-gamma, interferon-gamma-inducible protein-10, and monocyte chemoattractant protein-1 than controls. In HIV-infected participants, plasma soluble CD14 was positively associated with microstructural white matter (WM) damage, and plasma D-dimer was negatively associated with WM blood flow. In CSF, IL-6 was negatively associated with WM volume, and neurofilament heavy-chain (NFH) was negatively associated with intelligence quotient and working memory. These markers of ongoing inflammation, immune activation, coagulation, and neuronal damage could be used to further evaluate the pathophysiology and clinical course of cerebral and cognitive deficits in perinatally acquired HIV.

Global HIV neurology: a comprehensive review

: Neurological conditions associated with HIV remain major contributors to morbidity and mortality and are increasingly recognized in the aging population on long-standing combination antiretroviral therapy (cART). Importantly, growing evidence shows that the central nervous system (CNS) may serve as a reservoir for viral replication, which has major implications for HIV eradication strategies. Although there has been major progress in the last decade in our understanding of the pathogenesis, burden, and impact of neurological conditions associated with HIV infection, significant scientific gaps remain. In many resource-limited settings, antiretrovirals considered second or third line in the United States, which carry substantial neurotoxicity, remain mainstays of treatment, and patients continue to present with severe immunosuppression and CNS opportunistic infections. Despite this, increased global access to cART has coincided with an aging HIV-positive population with cognitive sequelae, cerebrovascular disease, and peripheral neuropathy. Further neurological research in low-income and middle-income countries (LMICs) is needed to address the burden of neurological complications in HIV-positive patients, particularly regarding CNS viral reservoirs and their effects on eradication.

Focus groups inform a mobile health intervention to promote adherence to a Mediterranean diet and engagement in physical activity among people living with HIV

Background

A personalized mobile health intervention (iSTEP) aims to promote a Mediterranean diet and increase physical activity, thereby improving neurocognitive functioning among persons living with HIV (PLWH). This article describes a qualitative study conducted to develop iSTEP for PLWH, including assessment of diet habits and preferences for tracking physical activity.

Method

Two focus groups, with seven and 13 PLWH respectively, discussed barriers and facilitators of a healthy diet and provided feedback to refine iSTEP components, including the feasibility of using a Fitbit and the content of text messages designed to encourage improved diet and physical activity.

Results

Focus group discussions revealed several healthy diet barriers, including housing instability, time required for food preparation, cost of healthy food, depression, gastrointestinal issues, physical disability, and changes in appetite since HIV diagnosis. Participant-identified healthy diet facilitators included affordable price options for healthy food, a structured food plan, desire to modify appearance or weight, access to medical professionals, motivation for disease prevention, and social support. Participants endorsed wearing a Fitbit on the wrist and receiving text messages as useful methods to monitor and encourage a better diet and greater physical activity.

Conclusions

These findings assisted the expansion of a mobile health intervention that promotes health behaviors in order to improve neurocognitive outcomes among PLWH.

Trial registration

NCT03123731, prospectively registered on ClinicalTrials.gov, April 21, 2017.

Global developments in HIV neurology

Neurologic conditions associated with HIV remain major contributors to morbidity and mortality, and are increasingly recognized in the aging population on long-standing combination antiretroviral therapy (cART). Importantly, growing evidence suggests that the central nervous system (CNS) serves as a reservoir for viral replication with major implications for human immunodeficiency virus (HIV) eradication strategies. Though there has been major progress in the last decade in our understanding of the pathogenesis, burden, and impact of HIV-associated neurologic conditions, significant scientific gaps remain. In many low-income settings, second- and third-line cART regimens that carry substantial neurotoxicity remain treatment mainstays. Further, patients continue to present severely immunosuppressed with CNS opportunistic infections. Public health efforts should emphasize improvements in access and optimizing treatment of HIV-positive patients, specifically in resource-limited settings, to reduce the risk of neurologic sequelae.

Contributions of Disease Severity, Psychosocial Factors, and Cognition to Behavioral Functioning in US Youth Perinatally Exposed to HIV

Among perinatally HIV-infected (PHIV) and perinatally HIV-exposed, uninfected (PHEU) youth, we evaluated the contributions of home environment, psychosocial, and demographic factors and, among PHIV only, HIV disease severity and antiretroviral treatment (ART), to cognitive functioning (CF) and behavioral functioning (BF). A structural equation modeling (SEM) approach was utilized. Exploratory factor analysis was used to reduce predictor variables to major latent factors. SEMs were developed to measure associations between the latent factors and CF and BF outcomes. Participants included 231 PHIV and 151 PHEU youth (mean age = 10.9 years) enrolled in the PHACS adolescent master protocol. Youth and caregivers completed assessments of CF, BF, psychosocial factors and HIV health. Medical data were also collected. Clusters of predictors were identified, establishing four parsimonious SEMs: child-assessed and caregiver-assessed BF in PHIV and PHEU youth. Among both groups, higher caregiver-child stress predicted worse BF. Caregiver resources and two disease severity variables, late presenter and better past HIV health, were significant predictors of CF in PHIV youth. Higher youth CF was associated with better caregiver-reported BF in both groups. Caregiver resources predicted caregiver-reported BF in PHEU youth, which was mediated via youth CF. Among PHIV youth, better past HIV health and caregiver resources mediated the effects of CF on caregiver-assessed BF. Using SEMs, we found a deleterious impact of caregiver and child stress on BF in both groups and of HIV disease factors on the CF of PHIV youth, reinforcing the importance of early comprehensive intervention to reduce risks for impairment.

Lower total and regional grey matter brain volumes in youth with perinatally-acquired HIV infection: Associations with HIV disease severity, substance use, and cognition

Despite improved survival due to combination antiretroviral therapy (cART), youth with perinatally-acquired HIV (PHIV) show cognitive deficits and developmental delay at increased rates. HIV affects the brain during critical periods of development, and the brain may be a persistent reservoir for HIV due to suboptimal blood brain barrier penetration of cART. We conducted structural magnetic resonance imaging (sMRI) and cognitive testing in 40 PHIV youth (mean age=16.7years) recruited from the NIH Pediatric HIV/AIDS Cohort Study (PHACS) who are part of the first generation of PHIV youth surviving into adulthood. Historical and current HIV disease severity and substance use measures were also collected. Total and regional cortical grey matter brain volumes were compared to a group of 334 typically-developing, HIV-unexposed and uninfected youth (frequency-matched for age and sex) from the Pediatric Imaging, Neurocognition, and Genetics (PING) study (mean age=16.1years). PHIV youth had smaller (2.8-5.1%) total and regional grey matter volumes than HIV-unexposed and uninfected youth, with smallest volumes seen among PHIV youth with higher past peak viral load (VL) and recent unsuppressed VL. In PHIV youth, worse cognitive performance correlated with smaller volumes. This pattern of smaller grey matter volumes suggests that PHIV infection may influence brain development and underlie cognitive dysfunction seen in this population. Among PHIV youth, smaller volumes were also linked to substance use (alcohol use: 9.0-13.4%; marijuana use: 10.1-16.0%). In this study, collection of substance use information was limited to the PHIV cohort; future studies should also collect substance use information in controls to further address interactions between HIV and substance use on brain volume.

Maternal urinary phthalates and sex-specific placental mRNA levels in an urban birth cohort

BACKGROUND

Prenatal urinary concentrations of phthalates in women participants in an urban birth cohort were associated with outcomes in their children related to neurodevelopment, autoimmune disease risk, and fat mass at 3,5,7, and 8 years of life. Placental biomarkers and outcomes at birth may offer biologic insight into these associations. This is the first study to address these associations with candidate genes from the phthalate and placenta literature, accounting for sex differences, and using absolute quantitation methods for mRNA levels.

METHODS

We measured candidate mRNAs in 180 placentas sampled at birth (HSD17B1, AHR, CGA, CYP19A1, SLC27A4, PTGS2, PPARG, CYP11A1) by quantitative PCR and an absolute standard curve. We estimated associations of log_e mRNA with quartiles of urinary phthalate monoesters using linear mixed models. Phthalate metabolites (N = 358) and mRNAs (N = 180) were transformed to a z-score and modeled as independent, correlated vectors in relation to large for gestational age (LGA) and gestational diabetes mellitus (GDM).

RESULTS

CGA was associated with 4 out of 6 urinary phthalates. CGA was 2.0 log_e units lower at the 3^rd vs. 1^st quartile of mono-n-butyl phthalate (MnBP) (95% confidence interval (CI): -3.5, -0.5) in male placentas, but 0.6 log_e units higher (95% CI: -0.8, 1.9) in female placentas (sex interaction p = 0.01). There was an inverse association of MnBP with PPARG in male placentas (-1.1 log_e units at highest vs. lowest quartile, 95% CI: -2.0, -0.1). CY19A1, CYP11A1, CGA were associated with one or more of the following in a sex-specific manner: monobenzyl phthalate (MBzP), MnBP, mono-iso-butyl phthalate (MiBP). These 3 mRNAs were lower by 1.4-fold (95% CI: -2.4, -1.0) in male GDM placentas vs. female and non-GDM placentas (p-value for interaction = 0.04). The metabolites MnBP/MiBP were 16% higher (95% CI: 0, 22) in GDM pregnancies.

CONCLUSIONS

Prenatal concentrations of certain phthalates and outcomes at birth were modestly associated with molecular changes in fetal placental tissue during pregnancy. Associations were stronger in male vs. female placentas, and associations with MnBP and MiBP were stronger than other metabolites. Placental mRNAs are being pursued further as potential mediators of exposure-induced risks to the health of the child.

Executive Functioning in Children and Adolescents With Perinatal HIV Infection and Perinatal HIV Exposure

BACKGROUND

Executive functions (EFs) are critical for management of life activities, but few studies have evaluated EFs in children and adolescents with perinatally acquired HIV (PHIV), who are at risk for problems in academics, behavior, and medication adherence. We compared EFs in youth with PHIV and in perinatally HIV-exposed but uninfected (PHEU) youth.

METHODS

Four Delis-Kaplan Executive Function System (D-KEFS) subtests were administered to 173 youth with PHIV and 85 PHEU youth, aged 9 to <19 years, who were enrolled in the Pediatric HIV/AIDS Cohort Study (PHACS) Memory and Executive Functioning Study. Youth with PHIV, with or without history of a Centers for Disease Control and Prevention Class C (AIDS-defining) condition (PHIV/C [n = 45] and PHIV/non-C [n = 128], respectively), were compared with each other and with PHEU youth. Among youth with PHIV, associations with measures of current and past disease severity were evaluated using adjusted linear regression models.

RESULTS

The PHIV/C group (mean age, 15.5 years), compared with the PHIV/non-C and PHEU groups (mean ages, 14.5 and 12.9 years, respectively), were significantly slower on the Inhibition and Color Naming/Reading Combined conditions of the Color-Word Interference subtest and made more errors on Inhibition; differences between the PHIV/C and PHEU groups persisted in adjusted models. No differences in adjusted means for fluency or problem-solving were found. The PHIV/non-C and PHEU groups did not differ on any measure. Associations of specific EF measures with HIV RNA viral load, CD4-positive T-lymphocyte percentage, and age at greatest disease severity were observed.

CONCLUSIONS

Youth with PHIV and previous AIDS-defining conditions performed more poorly on some EF measures. Relationships of EF development with the degree and timing of disease severity require further study. Implications for long-term outcomes and interventions are important avenues for follow-up.

Transfer of Maternal Antimicrobial Immunity to HIV-Exposed Uninfected Newborns

The transfer of maternal immune factors to the newborn is critical for protection from infectious disease in early life. Maternally acquired passive immunity provides protection until the infant is beyond early life's increased susceptibility to severe infections or until active immunity is achieved following infant's primary immunization. However, as reviewed here, human immunodeficiency virus (HIV) infection alters the transfer of immune factors from HIV-infected mothers to the HIV-exposed newborns and young infants. This may relate to the immune activation in HIV-infected pregnant women, associated with the production of inflammatory cytokines at the maternofetal interface associated with inflammatory responses in the newborn. We also summarize mother-targeting interventions to improve the health of infants born to HIV-infected women, such as immunization during pregnancy and reduction of maternal inflammation. Maternal immunization offers the potential to compensate for the decreased transplacentally transferred maternal antibodies observed in HIV-exposed infants. Current data suggest reduced immunogenicity of vaccines in HIV-infected pregnant women, possibly reducing the protective impact of maternal immunization for HIV-exposed infants. Fortunately, levels of antibodies appear preserved in the breast milk of HIV-infected women, which supports the recommendation to breast-feed during antiretroviral treatment to protect HIV-exposed infants.

The complement system, neuronal injury, and cognitive function in horizontally-acquired HIV-infected youth

The complement system (C1q/C3) is a key mediator of synaptic pruning during normal development. HIV inappropriately induces C1q and C3 production in the brain, and reduces neuronal complement inhibition. HIV may thus alter neural connectivity in the developing brain by excessively targeting synapses for elimination. The resultant pattern of neuronal injury may fundamentally alter neurodevelopmental and cognitive processes differentially across ages. This study aimed to (1) measure the association between the cerebrospinal fluid (CSF) complement factors (C1q/C3) and a marker of neuronal injury (NFL) in HIV+ subjects; (2) quantify the differences in CSF C1q/C3 between HIV+ youth and older adults; and (3) define the relationship between CSF C1q/C3 and cognitive impairment in each age group. We performed a retrospective cross-sectional study of 20 HIV+ 18–24-year-old youth and 20 HIV+ 40–46-year-old adults with varying levels of cognitive impairment enrolled in the CNS Antiretroviral Therapy Effects Research study. We quantified C3, C1q, and NFL by ELISA in paired CSF/plasma specimens. We found that CSF C1q correlates with NFL in all subjects not receiving antiretroviral therapy (n = 16, rho = 0.53, p = 0.035) when extreme NFL outliers were eliminated (n = 1). There was no difference in plasma/CSF C1q or C3 between older adults and youth. In 18–24-year-old youth, a nearly significant (p = 0.052) elevation of CSF C1q expression was observed in cognitively impaired subjects compared to cognitively normal subjects. Further investigation into the role of the CNS complement system in the neuropathogenesis of HIV is warranted and should be considered in a developmentally specific context.

Learning and Memory in Children and Adolescents With Perinatal HIV Infection and Perinatal HIV Exposure

BACKGROUND

Learning and memory in youth with perinatally acquired HIV (PHIV) are poorly understood, despite their importance for academic, healthcare and daily functioning.

METHODS

PHIV (n = 173) and perinatally HIV-exposed but uninfected (PHEU, n = 85) participants (aged 9-19 years) in a substudy of the Pediatric HIV/AIDS Cohort Study completed age-standardized tests of verbal and visual learning and delayed memory. Linear regression models implemented via generalized estimating equations were used to compare memory measures in PHEU participants versus PHIV youth with and without Centers for Disease Control and Prevention class C diagnosis (PHIV-C, n = 45 and PHIV-non-C, n = 128, respectively), adjusting for sociodemographic covariates.

RESULTS

Participants (mean age = 14.10 years) were 54% female, 75% Black and 18% Hispanic. Although unadjusted analyses showed significantly lower visual recognition memory and verbal delayed recall for PHIV-C compared with PHEU participants and lower verbal learning for PHIV-C and non-C groups compared with PHEU, differences persisted only for visual recognition memory after adjusting for sociodemographic covariates. For PHIV youth, current CD4% <25 was associated with poorer verbal learning, and older age at peak viral load was associated with poorer verbal delayed recall and design memory.

CONCLUSIONS

Youth with PHIV, particularly those with Centers for Disease Control and Prevention class C diagnosis, showed poorer performance on some measures of learning and memory compared with PHEU. Although group differences in verbal memory were largely attributable to sociodemographic characteristics, associations of class C diagnosis with poorer visual recognition memory and of current CD4% with poorer verbal learning suggest subtle effects of HIV on learning and memory in youth with PHIV.

Neurologic disease in HIV-infected children and the impact of combination antiretroviral therapy

The prevalence of HIV-associated neurocognitive impairment in perinatally HIV-infected children has declined since the introduction of combination antiretroviral therapy (cART). Early initiation of cART in infancy has been shown to positively impact neurodevelopment; however, children continue to be diagnosed with HIV outside of the early infancy period and can experience subtle to severe neurocognitive deficits despite cART. The causes of these neurocognitive deficits despite effective cART are multifactorial and likely include continued viral replication in the CNS, ongoing neuroinflammation, irreversible CNS injury prior to cART initiation, neurotoxic effects of cART, and socioeconomic and psychosocial effects. Many aspects of our understanding of HIV-associated neurocognitive disorders have emerged from research in adult patients, but perinatally HIV-infected children represent a very different population. These children were exposed to HIV during a period of rapid brain development and have lifelong infection and potential lifelong cART exposure. HIV is no longer a rapidly fatal disease, and most HIV-infected children in resource-rich countries are living into adulthood. It is therefore critical to optimize neurocognitive outcomes of these youth. This review summarizes current understanding of the pathogenesis of HIV-associated CNS infection and the impact of cART on neurocognitive function in children and adolescents and discusses important areas for future research.