Default Mode Connectivity in Youth With Perinatally Acquired HIV

Prevalence of detectable HIV-DNA and HIV-RNA in cerebrospinal fluid of youth with perinatal HIV and impaired cognition on antiretroviral therapy

OBJECTIVE

Central nervous system (CNS) HIV infection can impact cognition and may be an obstacle to cure in adolescents and young adults with perinatal HIV (AYAPHIV). IMPAACT2015 enrolled AYAPHIV on suppressive antiretroviral therapy (ART) with cognitive impairment to detect and quantify HIV in blood and cerebrospinal fluid (CSF).

DESIGN

IMPAACT2015 was a U.S.-based multi-site, exploratory, observational study.

METHODS

Cognitive impairment was defined as NIH Toolbox Fluid Cognition Composite score (FCCS) more than 1 standard deviation below age-adjusted normative group mean. Cell-free HIV-RNA and cell-associated HIV pol/gag -DNA and 10 biomarkers of inflammation/neuronal injury were measured in paired CSF and blood. ART exposure concentrations were quantified in hair.

RESULTS

Among 24 participants, 20 had successful CSF collection and 18 also met viral suppression criteria. Nine of 18 (50%) were female sex-at-birth, and 14 of 18 (78%) were black. Median (range) age was 20 years (13-27), time on ART was 18.3 years (8.0-25.5), and FCCS was 68 (53-80). HIV-DNA was detected in PBMCs from all participants. In CSF, two of 18 (11%, 95% CI: 1.4-34.7%) participants had detectable cell-free HIV-RNA, while HIV gag or pol -DNA was detectable in 13 of 18 (72%, 95% confidence interval: 47-90). Detectable HIV-DNA in CSF was associated with male sex-at-birth ( P  = 0.051), lower CD4 + cell count at enrollment ( P  = 0.016), and higher PBMC HIV pol -DNA copies ( P  = 0.058). Hair antiretroviral concentrations and biomarkers were not associated with CSF HIV-DNA detection.

CONCLUSION

We found that a high proportion of AYAPHIV with neurocognitive impairment had CSF cells harboring HIV-DNA during long-term virologic suppression. This evidence of persistent HIV-DNA in CSF suggests that the CNS should be considered in treatment and cure studies.

Relationship between brain structural network integrity and emotional symptoms in youth with perinatally-acquired HIV

Perinatally acquired HIV infection (PHIV) currently affects approximately 1.7 million children worldwide. Youth with PHIV (YPHIV) are at increased risk for emotional and behavioral symptoms, yet few studies have examined relationships between these symptoms and brain structure. Previous neuroimaging studies in YPHIV report alterations within the salience network (SN), cognitive control network (CCN), and default mode network (DMN). These areas have been associated with social and emotional processing, emotion regulation, and executive function. We examined structural brain network integrity from MRI using morphometric similarity networks and graph theoretical measures of segregation (transitivity), resilience (assortativity), and integration (global efficiency). We examined brain network integrity of 40 YPHIV compared to 214 youths without HIV exposure or infection. Amongst YPHIV, we related structural brain network metrics to the Emotional Symptoms Index of the Behavioral Assessment System for Children, 2nd edition. We also examined the relationship of inflammatory biomarkers in YPHIV to brain network integrity. YPHIV had significantly lower global efficiency in the SN, DMN, and the whole brain network compared to controls. YPHIV also demonstrated lower assortativity or resilience (i.e., network robustness) compared to controls in the DMN and whole brain network. Further, higher emotional symptom score was associated with higher global efficiency in the SN and lower global efficiency in the DMN, signaling more emotional challenges. A significant association was also found between several inflammatory and cardiac markers with structural network integrity. These findings suggest an impact of HIV on developing brain networks, and potential dysfunction of the SN and DMN in relation to network efficiency.

The default mode network is affected in the early stage of simian immunodeficiency virus infection: a longitudinal study

Acquired immune deficiency syndrome infection can lead to cognitive dysfunction represented by changes in the default mode network. Most recent studies have been cross-sectional and thus have not revealed dynamic changes in the default mode network following acquired immune deficiency syndrome infection and antiretroviral therapy. Specifically, when brain imaging data at only one time point are analyzed, determining the duration at which the default mode network is the most effective following antiretroviral therapy after the occurrence of acquired immune deficiency syndrome. However, because infection times and other factors are often uncertain, longitudinal studies cannot be conducted directly in the clinic. Therefore, in this study, we performed a longitudinal study on the dynamic changes in the default mode network over time in a rhesus monkey model of simian immunodeficiency virus infection. We found marked changes in default mode network connectivity in 11 pairs of regions of interest at baseline and 10 days and 4 weeks after virus inoculation. Significant interactions between treatment and time were observed in the default mode network connectivity of regions of interest pairs area 31/V6.R and area 8/frontal eye field (FEF). L, area 8/FEF.L and caudal temporal parietal occipital area (TPOC).R, and area 31/V6.R and TPOC.L. ART administered 4 weeks after infection not only interrupted the progress of simian immunodeficiency virus infection but also preserved brain function to a large extent. These findings suggest that the default mode network is affected in the early stage of simian immunodeficiency virus infection and that it may serve as a potential biomarker for early changes in brain function and an objective indicator for making early clinical intervention decisions.

Adaptation and construct validity evaluation of a tablet-based, short neuropsychological test battery for use with adolescents and young adults living with HIV in Thailand

OBJECTIVE

Deficits in neurocognitive functioning are common among adolescents and young adults (AYA) with perinatally acquired HIV (PHIV). Limitations of traditional neuropsychological tests hinder assessment of neurocognition in low- and middle-income countries where most AYA with PHIV reside. Computerized testing could make assessment of neurocognition more accessible in these countries. This study examined a culturally modified NeuroScreen, a tablet-based neurocognitive testing app, for use in Thailand. Construct validity was examined among Thai AYA (13-23 years) with and without PHIV.

METHOD

NeuroScreen underwent adaptation including language, content, and usability review by Thai psychologists, AYA, and clinical staff. One hundred Thai AYA (50 PHIV; 50 HIV-uninfected, matched controls) were administered the adapted NeuroScreen and a battery of traditional paper-and-pencil neuropsychological tests. Correlations, mean differences, and proportions with impaired performance were examined across NeuroScreen and the traditional tests.

RESULTS

The Thai version of NeuroScreen was deemed understandable and culturally appropriate. A large correlation (.82) between overall performance on the NeuroScreen and traditional batteries was observed. Small-to-large correlations were found between conceptually similar NeuroScreen and traditional tests of processing speed, working memory, motor speed, and executive functioning. Mean test performance differences between AYA with PHIV and controls were similar between test batteries. Both sets of tests identified similar rates of impaired participants.

CONCLUSIONS

Results provide support for the acceptability and construct validity of the Thai NeuroScreen tests to assess neurocognition in Thai AYA with PHIV. An easy-to-use tool to assess neurocognition can help Thai providers provide better care for AYA with PHIV. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Reduced neuronal population in the dorsolateral prefrontal cortex in infant macaques infected with simian immunodeficiency virus (SIV)

Pediatric HIV infection remains a global health crisis with an estimated 150,000 new mother-to-child (MTCT) infections each year. Antiretroviral therapy (ART) has improved childhood survival, but only an estimated 53% of children worldwide have access to treatment. Adding to the health crisis is the neurological impact of HIV on the developing brain, in particular cognitive and executive function, which persists even when ART is available. Imaging studies suggest structural, connectivity, and functional alterations in perinatally HIV-infected youth. However, the paucity of histological data limits our ability to identify specific cortical regions that may underlie the clinical manifestations. Utilizing the pediatric simian immunodeficiency virus (SIV) infection model in infant macaques, we have previously shown that early-life SIV infection depletes the neuronal population in the hippocampus. Here, we expand on these previous studies to investigate the dorsolateral prefrontal cortex (dlPFC). A total of 11 ART-naïve infant rhesus macaques (Macaca mulatta) from previous studies were retrospectively analyzed. Infant macaques were either intravenously (IV) inoculated with highly virulent SIVmac251 at ~1 week of age and monitored for 6-10 weeks or orally challenged with SIVmac251 from week 9 of age onwards with a monitoring period of 10-23 weeks post-infection (19-34 weeks of age), and SIV-uninfected controls were euthanized at 16-17 weeks of age. Both SIV-infected groups show a significant loss of neurons along with evidence of ongoing neuronal death. Oral- and IV-infected animals showed a similar neuronal loss which was negatively correlated to chronic viremia levels as assessed by an area under the curve (AUC) analysis. The loss of dlPFC neurons may contribute to the rapid neurocognitive decline associated with pediatric HIV infection.

Altered White Matter Tracts in the Somatosensory, Salience, Motor, and Default Mode Networks in 7-Year-Old Children Living with Human Immunodeficiency Virus: A Tractographic Analysis

Introduction: Even with the increased access and early initiation of combination antiretroviral therapy, children with perinatally acquired human immunodeficiency virus (CPHIV) continue to demonstrate white matter alterations. Children perinatally HIV-exposed, but uninfected (CHEU) alike show differences in white matter integrity compared with children who are HIV-unexposed and uninfected (CHUU). Objectives: Mapping white matter connections that link gray matter regions that form resting-state (RS) functional networks may demonstrate whether structural and functional connectivity alterations in HIV infection and exposure may be related. We hypothesized reduced structural connectivity in CPHIV within the default mode network (DMN), visual, ventral DMN (vDMN), somatosensory, salience, auditory, motor, executive, basal ganglia, and posterior DMN (pDMN). We also hypothesized that CHEU will have increased structural connectivity compared with CHUU in the vDMN, somatosensory, pDMN, dorsal attention, salience, auditory, motor and basal ganglia. Methods: Study participants were 61 seven-year-old CPHIV and 46 age-matched children who are HIV uninfected (CHU) (19 CHEU). We used diffusion tensor imaging-based tractography to investigate white matter connections that link gray matter regions within RS functional networks. Results: We found altered white matter integrity in the somatosensory, salience, default mode, and motor networks of CPHIV compared with CHU. The superior temporal cortex, superior frontal cortex, and putamen were affected in all four networks and have also been reported to demonstrate morphological alterations in the same cohort. In CHEU, white matter integrity was higher in the visual network, pDMN, and motor network compared with CHUU. Conclusion: Our results suggest that altered white matter integrity may influence gray matter morphology and functional network alterations. Impact statement The long-term effects of human immunodeficiency virus (HIV) and exposure on the developing brain in the combination antiretroviral therapy era are still not well known. We use diffusion tensor imaging-based tractography to explore these effects on white matter connections that link gray matter regions within functional networks. Our findings provide a context for HIV-associated white matter and connectivity abnormalities.

Multivariate approach for longitudinal analysis of brain metabolite levels from ages 5-11 years in children with perinatal HIV infection

Treatment guidelines recommend that children with perinatal HIV infection (PHIV) initiate antiretroviral therapy (ART) early in life and remain on it lifelong. As part of a longitudinal study examining the long-term consequences of PHIV and early ART on the developing brain, 89 PHIV children and a control group of 85 HIV uninfected children (HIV-) received neuroimaging at ages 5, 7, 9 and 11 years, including single voxel magnetic resonance spectroscopy (MRS) in three brain regions, namely the basal ganglia (BG), midfrontal gray matter (MFGM) and peritrigonal white matter (PWM). We analysed age-related changes in absolute metabolite concentrations using a multivariate approach traditionally applied to ecological data, the Correlated Response Model (CRM) and compared these to results obtained from a multilevel mixed effect modelling (MMEM) approach. Both approaches produce similar outcomes in relation to HIV status and age effects on longitudinal trajectories. Both methods found similar age-related increases in both PHIV and HIV- children in almost all metabolites across regions. We found significantly elevated GPC+PCh across regions (95% CI=[0.033; 0.105] in BG; 95% CI=[0.021; 0.099] in PWM; 95% CI=[0.059; 0.137] in MFGM) and elevated mI in MFGM (95% CI=[0.131; 0.407]) among children living with PHIV compared to HIV- children; additionally the CRM model also indicated elevated mI in BG (95% CI=[0.008; 0.248]). These findings suggest persistent inflammation across the brain in young children living with HIV despite early ART initiation.

White matter of perinatally HIV infected older youths shows low frequency fluctuations that may reflect glial cycling

In perinatally HIV-infected (PHIV) children, neurodevelopment occurs in the presence of HIV-infection, and even with combination antiretroviral therapy (cART) the brain can be a reservoir for latent HIV. Consequently, patients often demonstrate long-term cognitive deficits and developmental delay, which may be reflected in altered functional brain activity. Our objective was to examine brain function in PHIV on cART by quantifying the amplitude of low frequency fluctuations (ALFF) and regional homogeneity (ReHo). Further, we studied ALFF and ReHo changes with neuropsychological performance and measures of immune health including CD4 count and viral loads in the HIV-infected youths. We found higher ALFF and ReHo in cerebral white matter in the medial orbital lobe for PHIV (N = 11, age mean ± sd = 22.5 ± 2.9 years) compared to controls (N = 16, age = 22.5 ± 3.0 years), with age and gender as co-variates. Bilateral cerebral white matter showed increased spontaneous regional activity in PHIV compared to healthy controls. No brain regions showed lower ALFF or ReHo in PHIV compared to controls. Higher log10 viral load was associated with higher ALFF and ReHo in PHIV in bilateral cerebral white matter and right cerebral white matter respectively after masking the outcomes intrinsic to the brain regions that showed significantly higher ALFF and ReHo in the PHIV compared to the control. Reductions in social cognition and abstract thinking in PHIV were correlated with higher ALFF at the left cerebral white matter in the left medial orbital gyrus and higher ReHo at the right cerebral white matter in the PHIV patients. Although neuroinflammation and associated neuro repair were not directly measured, the findings support their potential role in PHIV impacting neurodevelopment and cognition.

Synergistic effects of HIV and marijuana use on functional brain network organization

HIV is associated with disruptions in cognition and brain function. Marijuana use is highly prevalent in HIV but its effects on resting brain function in HIV are unknown. Brain function can be characterized by brain activity that is correlated between regions over time, called functional connectivity. Neuropsychiatric disorders are increasingly being characterized by disruptions in such connectivity. We examined the synergistic effects of HIV and marijuana use on functional whole-brain network organization during resting state. Our sample included 78 adults who differed on HIV and marijuana status (19 with co-occurring HIV and marijuana use, 20 HIV-only, 17 marijuana-only, and 22 controls). We examined differences in local and long-range brain network organization using eight graph theoretical metrics: transitivity, local efficiency, within-module degree, modularity, global efficiency, strength, betweenness, and participation coefficient. Local and long-range connectivity were similar between the co-occurring HIV and marijuana use and control groups. In contrast, the HIV-only and marijuana-only groups were both associated with disruptions in brain network organization. These results suggest that marijuana use in HIV may normalize disruptions in brain network organization observed in persons with HIV. However, future work is needed to determine whether this normalization is suggestive of a beneficial or detrimental effect of marijuana on cognitive functioning in HIV.

State of the Mind: Growing up with HIV

Human immunodeficiency virus (HIV) is a neurotropic virus that has a detrimental impact on the developing central nervous system (CNS) of children growing up with perinatal HIV (PHIV) due to a combination of pathophysiological processes related to direct viral cytopathic effects and immune activation. This leads to a spectrum of neurocognitive impairment ranging from severe encephalopathy to subtle domain-specific cognitive impairments, as well as psychological disorders that are compounded by HIV-related stigma and sociodemographic factors that disproportionately affect PHIV children. Early commencement and consistent use of combination antiretroviral therapy (cART) has resulted in a dramatic improvement in neuropsychological outcomes for PHIV children; however, they remain vulnerable to cognitive impairment and psychological disorders, as evidenced by imaging findings, randomised clinical trials and observational studies. An optimal neuroprotective cART regimen remains elusive in children, but systemic viral suppression, regular neurocognitive and psychological screening and ready access to neuropsychological management strategies are key components for optimising neuropsychological outcomes. However, a lack of standardised and validated screening tools, particularly in resource-limited settings, hinders a precise understanding of the nature, prevalence and associations between neuropsychological symptomatology and HIV health. This article reviews the natural history, cellular pathophysiology and structural and functional imaging findings for children growing up with HIV, as well as summarising management strategies related to antiretroviral therapy, screening tools and specific interventions for neurocognitive impairments and psychological disorders.

Brain morphometric differences in youth with and without perinatally-acquired HIV: A cross-sectional study

•

We performed vertex-wise analyses comparing grey matter in youth with and without perinatally-acquired HIV (PHIV).

•

PHIV youth had reduced cortical thickness, surface area, and gyrification compared to control youth.

•

PHIV youth did not exhibit the same pattern of inverse grey matter-age relationships that were observed in control youth.

Youth with perinatally-acquired HIV (PHIV) experience specific and global cognitive deficits at increased rates compared to typically-developing HIV-uninfected youth. In youth with PHIV, HIV infects the brain early in development. Neuroimaging studies have demonstrated altered grey matter morphometry in youth with PHIV compared to typically-developing youth. This study examined cortical thickness, surface area, and gyrification of grey matter in youth (age 11–20 years old) with PHIV (n = 40) from the Pediatric HIV/AIDS Cohort Study (PHACS) compared to typically-developing presumed HIV uninfected and unexposed youth (n = 80) from the Pediatric Imaging, Neurocognition and Genetics Study (PING) using structural magnetic resonance imaging. This study also examined the relationship between grey matter morphometry and age. Youth with PHIV had reduced cortical thickness, surface area, and gyrification compared to typically-developing youth. In addition, an inverse relationship between age and grey matter volume was found in typically-developing youth, but was not observed in youth with PHIV. Longitudinal studies are necessary to understand the neurodevelopmental trajectory of youth with PHIV.

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.

Mapping abnormal subcortical neurodevelopment in a cohort of Thai children with HIV

Alterations in subcortical brain structures have been reported in adults with HIV and, to a lesser extent, pediatric cohorts. The extent of longitudinal structural abnormalities in children with perinatal HIV infection (PaHIV) remains unclear. We modeled subcortical morphometry from whole brain structural magnetic resonance imaging (1.5 T) scans of 43 Thai children with PaHIV (baseline age = 11.09±2.36 years) and 50 HIV- children (11.26±2.80 years) using volumetric and surface-based shape analyses. The PaHIV sample were randomized to initiate combination antiretroviral treatment (cART) when CD4 counts were 15-24% (immediate: n = 22) or when CD4 < 15% (deferred: n = 21). Follow-up scans were acquired approximately 52 weeks after baseline. Volumetric and shape descriptors capturing local thickness and surface area dilation were defined for the bilateral accumbens, amygdala, putamen, pallidum, thalamus, caudate, and hippocampus. Regression models adjusting for clinical and demographic variables examined between and within group differences in morphometry associated with HIV. We assessed whether baseline CD4 count and cART status or timing associated with brain maturation within the PaHIV group. All models were adjusted for multiple comparisons using the false discovery rate. A pallidal subregion was significantly thinner in children with PaHIV. Regional thickness, surface area, and volume of the pallidum was associated with CD4 count in children with PaHIV. Longitudinal morphometry was not associated with HIV or cART status or timing, however, the trajectory of the left pallidum volume was positively associated with baseline CD4 count. Our findings corroborate reports in adult cohorts demonstrating a high predilection for HIV-mediated abnormalities in the basal ganglia, but suggest the effect of stable PaHIV infection on morphological aspects of brain development may be subtle.

Diagnostic and prognostic biomarkers for HAND

In 2007, the nosology for HIV-1-associated neurocognitive disorders (HAND) was updated to a primarily neurocognitive disorder. However, currently available diagnostic tools lack the sensitivity and specificity needed for an accurate diagnosis for HAND. Scientists and clinicians, therefore, have been on a quest for an innovative biomarker to diagnose (i.e., diagnostic biomarker) and/or predict (i.e., prognostic biomarker) the progression of HAND in the post-combination antiretroviral therapy (cART) era. The present review examined the utility and challenges of four proposed biomarkers, including neurofilament light (NFL) chain concentration, amyloid (i.e., sAPPα, sAPPβ, amyloid β) and tau proteins (i.e., total tau, phosphorylated tau), resting-state functional magnetic resonance imaging (fMRI), and prepulse inhibition (PPI). Although significant genotypic differences have been observed in NFL chain concentration, sAPPα, sAPPβ, amyloid β, total tau, phosphorylated tau, and resting-state fMRI, inconsistencies and/or assessment limitations (e.g., invasive procedures, lack of disease specificity, cost) challenge their utility as a diagnostic and/or prognostic biomarker for milder forms of neurocognitive impairment (NCI) in the post-cART era. However, critical evaluation of the literature supports the utility of PPI as a powerful diagnostic biomarker with high accuracy (i.e., 86.7-97.1%), sensitivity (i.e., 89.3-100%), and specificity (i.e., 79.5-94.1%). Additionally, the inclusion of multiple CSF and/or plasma markers, rather than a single protein, may provide a more sensitive diagnostic biomarker for HAND; however, a pressing need for additional research remains. Most notably, PPI may serve as a prognostic biomarker for milder forms of NCI, evidenced by its ability to predict later NCI in higher-order cognitive domains with regression coefficients (i.e., r) greater than 0.8. Thus, PPI heralds an opportunity for the development of a brief, noninvasive diagnostic and promising prognostic biomarker for milder forms of NCI in the post-cART era.

Effects of early HIV infection and combination antiretroviral therapy on intrinsic brain activity: a cross-sectional resting-state fMRI study

Objective: To investigate effects of early HIV infection and combination antiretroviral therapy (cART) on intrinsic brain activity by using amplitude of low-frequency fluctuation (ALFF) analysis. Patients and methods: Forty-nine HIV patients, including 26 with cART (HIV+/cART+) and 23 treatment-naïve (HIV+/cART-), and 25 matched healthy controls (HCs) underwent resting-state functional magnetic resonance imaging examination. ALFF values were compared by using one-way ANOVA tests with Analysis of Functional NeuroImages (AFNI)'s 3dClustSim correction (voxel p<0.005, α<0.05). In addition, the ALFF values of brain regions that showed significant differences among the three groups were correlated with clinical and neuropsychological variables in both groups of patients by using Spearman correlation analysis. Results: ANOVA analysis showed that statistic difference of ALFF values among three groups was located in the occipital cortex. Post hoc analysis showed a decrease in occipital ALFF value in HIV patients compared to HC, but showed no difference of occipital ALFF between HIV+/cART+ and HIV+/cART-. Additionally, compared with HC, HIV+/cART+ exhibited higher ALFF in the right caudate and frontoparietal cortex, and HIV+/cART- showed higher ALFF in the bilateral caudate. HIV+/cART+ demonstrated higher ALFF values in auditory cortex than HIV+/cART-. Moreover, ALFF values in the right occipital cortex were positively associated with CD4⁺/CD8⁺ ratio and executive function in HIV+/cART-. Conclusion: Early HIV-infected individuals presented reduced spontaneous brain activity in the occipital cortex. cART appeared to be ineffective in halting the HIV-induced neurodegeneration but might delay the progression of neural dysfunction to some extent. ALFF might be a potential biomarker in monitoring the effects of HIV and cART on brain function.

Changes in resting-state functional brain activity are associated with waning cognitive functions in HIV-infected children

Delayed brain development in perinatally HIV-infected children may affect the functional brain activity and subsequently cognitive function. The current study evaluated the functional brain activity in HIV-infected children by quantifying the amplitude of low frequency fluctuations (ALFF) and functional connectivity (FC). Additionally, correlation of ALFF and FC with cognitive measures was performed. Twenty-six HIV-infected children and 20 control children underwent neuropsychological (NP) assessment and resting-state functional magnetic resonance imaging (rs-fMRI). ALFF and FC maps were generated and group differences were analyzed using two-sample t-test. Furthermore, ALFF and FC showing significant group differences were correlated with NP scores using Pearson's correlation. Significantly lower ALFF in the left middle temporal gyrus, precentral and post central gyrus was observed in HIV-infected children compared to controls. FC was significantly reduced in the right inferior parietal, vermis, middle temporal and left postcentral regions, and significantly increased in the right precuneus, superior parietal and left middle frontal regions in HIV-infected children as compared to control. HIV-infected children showed significantly lower NP scores in various domains including closure, exclusion, memory, verbal meaning, quantity and hidden figure than controls. These waning cognitive functions were significantly associated with changes in ALFF and FC in HIV-infected children. The findings suggest that abnormal ALFF and FC may responsible for cognitive deficits in HIV-infected children. ALFF and FC in association with cognitive evaluation may provide a clinical biomarker to evaluate functional brain activity and to plan neurocognitive intervention in HIV-infected children undergoing standard treatment.

Asymptomatic Human Immunodeficiency Virus Vertical Transmitted Adolescents' Brain Functional Changes: Based on Resting-State Functional Magnetic Resonance Imaging

Perinatal HIV-infected (PHIV+) adolescents survive longer with the use of readily found combination antiretroviral therapy (cART); however, they still have the risk of developing cognitive deficits. The article aims to explore the brain functional changes in asymptomatic PHIV+ adolescents with cART based on the resting-state functional magnetic resonance imaging (rs-fMRI). rs-fMRI was performed on 20 PHIV+ adolescents and 28 PHIV- controls to evaluate the regional homogeneity (ReHo) in different brain regions by calculating the Kendall harmonious coefficient. Montreal cognitive assessment and laboratory studies (nadir CD4+ T cell counts) were also performed on all the subjects to evaluate their cognitive and immune status. Thirteen PHIV+ adolescents and 22 PHIV- controls were enrolled. There was a significant difference of ReHo values in PHIV+ adolescents compared to PHIV- controls, the areas with increased ReHo values include bilateral precentral/postcentral gyrus and right middle temporal pole. Also, the areas with decreased ReHo values locate in right putamen/pallidum/insula, left caudate/putamen/insula, right superior temporal pole/insula, right caudate/putamen, bilateral anterior cingulate cortex, and left inferior temporal pole. Furthermore, age, cognitive scores, and laboratory studies (nadir CD4+ T cell counts) did not show any significant correlation with altered ReHo values of brain regions neither in PHIV+ groups nor in PHIV- control groups. Among PHIV+ adolescents, brain areas with increased ReHo values were mainly located in the central somatic motor-sensory cortex, which might be related to the compensatory mechanism, whereas brain areas with decreased ReHo values were mainly focused on corticostriatal pathway, which might be associated with abnormal dopamine consumption. Thus, rs-fMRI could demonstrate the brain functional changes in resting state of asymptomatic PHIV+ adolescents.

Functional Connectivity Alterations between Networks and Associations with Infant Immune Health within Networks in HIV Infected Children on Early Treatment: A Study at 7 Years

Although HIV has been shown to impact brain connectivity in adults and youth, it is not yet known to what extent long-term early antiretroviral therapy (ART) may alter these effects, especially during rapid brain development in early childhood. Using both independent component analysis (ICA) and seed-based correlation analysis (SCA), we examine the effects of HIV infection in conjunction with early ART on resting state functional connectivity (FC) in 7 year old children. HIV infected (HIV+) children were from the Children with HIV Early Antiretroviral Therapy (CHER) trial and all initiated ART before 18 months; uninfected children were recruited from an interlinking vaccine trial. To better understand the effects of current and early immune health on the developing brain, we also investigated among HIV+ children the association of FC at 7 years with CD4 count and CD4%, both in infancy (6–8 weeks) and at scan. Although we found no differences within any ICA-generated resting state networks (RSNs) between HIV+ and uninfected children (27 HIV+, 18 uninfected), whole brain connectivity to seeds located at RSN connectivity peaks revealed several loci of FC differences, predominantly from seeds in midline regions (posterior cingulate cortex, paracentral lobule, cuneus, and anterior cingulate). Reduced long-range connectivity and increased short-range connectivity suggest developmental delay. Within the HIV+ children, clinical measures at age 7 years were not associated with FC values in any of the RSNs; however, poor immune health during infancy was associated with localized FC increases in the somatosensory, salience and basal ganglia networks. Together these findings suggest that HIV may affect brain development from its earliest stages and persist into childhood, despite early ART.

Imaging studies of the HIV-infected brain

Human immunodeficiency virus (HIV) enters the brain early after infecting humans and may remain in the central nervous system despite successful antiretroviral treatment. Many neuroimaging techniques were used to study HIV+ patients with or without opportunistic infections. These techniques assessed abnormalities in brain structures (using computed tomography, structural magnetic resonance imaging (MRI), diffusion MRI) and function (using functional MRI at rest or during a task, and perfusion MRI with or without a contrast agent). In addition, single-photon emission computed tomography with various tracers (e.g., thallium-201, Tc99-HMPAO) and positron emission tomography with various agents (e.g., [18F]-dexoyglucose, [11C]-PiB, and [11C]-TSPO tracers), were applied to study opportunistic infections or HIV-associated neurocognitive disorders. Neuroimaging provides diagnoses and biomarkers to quantitate the severity of brain injury or to monitor treatment effects, and may yield insights into the pathophysiology of HIV infection. As the majority of antiretroviral-stable HIV+ patients are living longer, age-related comorbid disorders (e.g., additional neuroinflammation, cerebrovascular disorders, or other dementias) will need to be considered. Other highly prevalent conditions, such as substance use disorders, psychiatric illnesses, and the long-term effects of combined antiretroviral therapy, all may lead to additional brain injury. Neuroimaging studies could provide knowledge regarding how these comorbid conditions impact the HIV-infected brain. Lastly, specific molecular imaging agents may be needed to assess the central nervous system viral reservoir.

Impact of Perinatally Acquired HIV Disease Upon Longitudinal Changes in Memory and Executive Functioning

BACKGROUND

Little is known regarding effects of perinatally acquired HIV infection (PHIV) on longitudinal change in memory and executive functioning (EF) during adolescence despite the importance of these skills for independence in adulthood.

METHODS

PHIV (n = 144) and perinatally HIV-exposed uninfected youth (PHEU, n = 79), ages 12-17, completed standardized tests of memory and EF at baseline and 2 years later. Changes from baseline for each memory and EF outcome were compared between PHEU and PHIV youth with (PHIV/C, n = 39) and without (PHIV/non-C, n = 105) history of CDC class C (AIDS-defining) diagnoses. Among PHIV youth, associations of baseline and past disease severity with memory and EF performance at follow-up were evaluated using adjusted linear regression models.

RESULTS

Participants were primarily black (79%); 16% were Hispanic; 55% were female. Mean memory and EF scores at follow-up generally fell in the low-average to average range. Pairwise comparison of adjusted mean change from baseline to follow-up revealed significantly greater change for PHIV/non-C compared with PHEU youth in only one verbal recognition task, with a difference in mean changes for PHIV/non-C versus PHEU of -0.99 (95% CI: -1.80 to -0.19; P = 0.02). Among youth with PHIV, better immunologic status at baseline was positively associated with follow-up measures of verbal recall and recognition and cognitive inhibition/flexibility. Past AIDS-defining diagnoses and higher peak viral load were associated with lower performance across multiple EF tasks at follow-up.

CONCLUSIONS

Youth with PHIV demonstrated stable memory and EF during a 2-year period of adolescence, allowing cautious optimism regarding long-term outcomes.

Combination antiretroviral therapy improves cognitive performance and functional connectivity in treatment-naïve HIV-infected individuals

Our study aimed to investigate the short-term effect of combination antiretroviral therapy (cART) on cognitive performance and functional and structural connectivity and their relationship to plasma levels of antiretroviral (ARV) drugs. Seventeen ARV treatment-naïve HIV-infected individuals (baseline mean CD4 cell count, 479 ± 48 cells/mm³) were age matched with 17 HIV-uninfected individuals. All subjects underwent a detailed neurocognitive and functional assessment and magnetic resonance imaging. HIV-infected subjects were scanned before starting cART and 12 weeks after initiation of treatment. Uninfected subjects were assessed once at baseline. Functional connectivity (FC) was assessed within the default mode network while structural connectivity was assessed by voxel-wise analysis using tract-based spatial statistics (TBSS) and probabilistic tractography within the DMN. Tenofovir and emtricitabine blood concentration were measured at week 12 of cART. Prior to cART, HIV-infected individuals had significantly lower cognitive performance than control subjects as measured by the total Z-score from the neuropsychological tests assessing six cognitive domains (p = 0.020). After 12 weeks of cART treatment, there remained only a weak cognitive difference between HIV-infected and HIV-uninfected subjects (p = 0.057). Mean FC was lower in HIV-infected individuals compared with those uninfected (p = 0.008), but FC differences became non-significant after treatment (p = 0.197). There were no differences in DTI metrics between HIV-infected and HIV-uninfected individuals using the TBSS approach and limited evidence of decreased structural connectivity within the DMN in HIV-infected individuals. Tenofovir and emtricitabine plasma concentrations did not correlate with either cognitive performance or imaging metrics.

CONCLUSIONS

Twelve weeks of cART improves cognitive performance and functional connectivity in ARV treatment-naïve HIV-infected individuals with relatively preserved immune function. Longer periods of observation are necessary to assess whether this effect is maintained.

Reduced functional connectivity between ventromedial prefrontal cortex and insula relates to longer corrected QT interval in HIV+ and HIV- individuals

OBJECTIVE

Prolongation of the QT interval, i.e., measure of the time between the start of the Q wave and the end of the T wave, is a precursor to fatal cardiac arrhythmias commonly observed in individuals infected with the Human Immunodeficiency Virus (HIV), and is related to dysregulation of the autonomic nervous system. We investigated the relationship between QT interval length and resting state functional connectivity (rsFC) of the ventromedial prefrontal cortex (VMPFC), a core region of the brain that is involved with cardio-autonomic regulation.

METHOD

Eighteen HIV+ men on antiretroviral therapy and with no history of heart disease were compared with 26 HIV-negative control subjects who had similar demographic and cardio-metabolic characteristics. A seed-based rsFC analysis of the right and left VMPFC was performed at the individual subject level, and 2nd-level analyses were conducted to identify the following: group differences in connectivity, brain regions correlating with corrected (QTc) interval length before and after controlling for those group differences, and regions where seed-based rsFC correlates with CD4 count and QTc interval within HIV+ individuals.

RESULTS

HIV-negative adults showed greater rsFC between the VMPFC seed regions and several default mode network structures. Across groups greater rsFC with the left anterior insula was associated with shorter QTc intervals, whereas right posterior insula connectivity with the VMPFC correlated with greater QTc intervals. HIV patients with lower CD4 counts and higher QTc intervals showed greater rsFC between the right VMPFC and the right posterior insula and dorsal cingulate gyrus.

CONCLUSIONS

This study demonstrates that QTc interval lengths are associated with distinct patterns of VMPFC rsFC with posterior and anterior insula. In HIV patients, longer QTc interval and lower CD4 count corresponded to weaker VMPFC connectivity with the dorsal striatrum.

SIGNIFICANCE

A forebrain control mechanism may be implicated in the suppression of cardiovagal influence that confers risk for ventricular arrhythmias and sudden cardiac death in HIV+ individuals.

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.

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.

Deformed Subcortical Structures Are Related to Past HIV Disease Severity in Youth With Perinatally Acquired HIV Infection

BACKGROUND

Combination antiretroviral therapy has led to increased survival among youth with perinatally acquired HIV (PHIV). However, cognitive deficits continue to be common. Histopathological studies in adults have found HIV concentrated in subcortical structures, which are involved in sensory processing, movement, and higher-order cognition that emerges with development.

METHODS

We conducted magnetic resonance imaging and cognitive testing in 40 youth with PHIV at one site of the Adolescent Master Protocol of the Pediatric HIV/AIDS Cohort Study. We collected HIV disease-severity measures and substance-use reports. Subcortical volume and shape deformation were generated with FreeSurfer-Initiated Large Deformation Diffeomorphic Metric Mapping. Inward shape deformation was defined as negative displacement. We evaluated associations of subcortical shape deformation with past HIV severity after adjustment for sex, age at neuroimaging, age at HIV severity marker, and substance use. We examined associations between subcortical deformation and cognitive function.

RESULTS

Negative correlations between shape deformation and peak HIV viral load (VL) were found in clusters in the caudate tail, globus pallidus, lateral putamen, and anterior and medial thalamus. Positive correlations between shape deformation and nadir CD4-positive T-lymphocyte percentage (CD4%) were found in clusters in the medial and posterior thalamus. Inward deformation in caudate and thalamic clusters correlated with worse cognition.

CONCLUSIONS

Youth with PHIV have demonstrable subcortical shape deformation related to past HIV severity and cognition; inward deformation was associated with higher peak VL, lower nadir CD4%, and worse cognition. Identifying subcortical deformation may inform clinical practice for early intervention to help improve cognitive outcomes and assess the neuroefficacy of combination antiretroviral therapy in youth with PHIV.