Neurologic abnormalities in HIV-1 infected children in the era of combination antiretroviral therapy

Early Antiretroviral Therapy Reduces Severity but Does Not Eliminate Neurodevelopmental Compromise in Children With HIV

BACKGROUND

Early antiretroviral therapy (ART) during infancy reduces cognitive impairment due to HIV, but the extent of benefit is unclear.

SETTING

Children were recruited from hospital and health centers providing HIV care and treatment in Nairobi, Kenya.

METHODS

Cognitive, behavioral, and motor outcomes were assessed in children with HIV and early ART (<1 year), children with HIV and late ART (1.5-6 years), and children HIV-unexposed uninfected (CHUU). Domain z scores and odds neurobehavioral impairment (≤15th percentile in CHUU) were compared in adjusted analyses.

RESULTS

Children with HIV initiated ART at median ages 0.4 (early ART) and 3.5 years (late ART). Children were assessed at median ages 6.9 (CHUU, N = 61), 6.9 (early ART, N = 54), and 13.5 (late ART; N = 27) years. Children with late ART vs. children with early ART had significantly lower z scores in 7 domains, specifically global cognition, short-term memory, visuospatial processing, learning, nonverbal test performance, executive function, and motor skills (adjusted mean differences, -0.42 to -0.62, P values ≤ 0.05), and had higher odds impairment in 7 domains (adjusted odds ratios [aORs], 2.87 to 16.22, P values ≤ 0.05). Children with early ART vs. CHUU had lower z scores in 5 domains (global cognition, short-term memory, delayed memory, processing speed, and behavioral regulation [adjusted mean differences, -0.32 to -0.88, P values < 0.05]) and higher impairment for 2 domains (short-term memory [aOR, 3.88] and behavioral regulation [aOR 3.46], P values < 0.05). Children with late ART vs. CHUU had lower z scores in 8 domains (adjusted mean differences, -0.57 to -1.05, P values ≤ 0.05), and higher impairment in 7 domains (aORs 1.98 to 2.32, P values ≤ 0.05).

CONCLUSION

Early ART in the first year of life attenuates but does not eliminate the neurodevelopmental compromise of HIV.

Multimodal magnetic resonance neuroimaging measures characteristic of early cART-treated pediatric HIV: A feature selection approach

Children with perinatally acquired HIV (CPHIV) have poor cognitive outcomes despite early combination antiretroviral therapy (cART). While CPHIV-related brain alterations can be investigated separately using proton magnetic resonance spectroscopy (1 H-MRS), structural magnetic resonance imaging (sMRI), diffusion tensor imaging (DTI), and functional MRI (fMRI), a set of multimodal MRI measures characteristic of children on cART has not been previously identified. We used the embedded feature selection of a logistic elastic-net (EN) regularization to select neuroimaging measures that distinguish CPHIV from controls and measured their classification performance via the area under the receiver operating characteristic curve (AUC) using repeated cross validation. We also wished to establish whether combining MRI modalities improved the models. In single modality analysis, sMRI volumes performed best followed by DTI, whereas individual EN models on spectroscopic, gyrification, and cortical thickness measures showed no class discrimination capability. Adding DTI and 1 H-MRS in basal measures to sMRI volumes produced the highest classification performancevalidation accuracy = 85 % AUC = 0.80 . The best multimodal MRI set consisted of 22 DTI and sMRI volume features, which included reduced volumes of the bilateral globus pallidus and amygdala, as well as increased mean diffusivity (MD) and radial diffusivity (RD) in the right corticospinal tract in cART-treated CPHIV. Consistent with previous studies of CPHIV, select subcortical volumes obtained from sMRI provide reasonable discrimination between CPHIV and controls. This may give insight into neuroimaging measures that are relevant in understanding the effects of HIV on the brain, thereby providing a starting point for evaluating their link with cognitive performance in CPHIV.

Risk and protective factors for depressive symptoms among the youth living with HIV in Namibia

BACKGROUND

: Namibia has one of the highest HIV prevalence rates among young people living with HIV and AIDS. The study of mental well-being among this vulnerable population is emerging as an important area of public health research.

METHODS

: This study examined how gender, social support, food insecurity, HIV-related stigma, HIV treatment adherence and HIV transmission knowledge are related to depressive symptoms among young people living with HIV in rural northern Namibia. Data were collected from 188 participants from the Zambezi region.

RESULTS

: The hierarchical regression analysis revealed that being a female infected with HIV, having perceived food insecurity, experiencing more HIV-related stigma and having low levels of social support can exacerbate the severity of depressive symptoms in this sample of Namibian youth.

DISCUSSION

: Our findings point to the need to expand social support interventions, enhance socio-economic programmes and reduce HIV-related stigma among young people living with HIV, especially those residing in rural, HIV endemic, resource-limited communities in developing countries.

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.

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.

Recovery of HIV encephalopathy in perinatally infected children on antiretroviral therapy

AIM

To describe the trajectory of clinical signs in children who developed human immunodeficiency virus encephalopathy (HIVE) after starting early antiretroviral therapy (ART).

METHOD

This was a retrospective case-cohort description of HIVE among Cape Town participants from the Children with HIV Early AntiRetroviral treatment (CHER) trial. Criteria for HIVE diagnosis were at least two of: (1) acquired central motor deficit, (2) impaired brain growth, and (3) failure to attain or loss of developmental milestones in the absence of an alternative aetiology.

RESULTS

Of 133 surviving participants who initiated ART at a median age of 9 weeks and who were followed until a median age of 6 years, 20 (12%) developed HIVE at a median age 31 months (interquartile range 19-37). In these, the first neurological deterioration was noticed at a median age of 19 months, when 16 were on ART and nine had undetectable HIV viral load for a median of 12 months. Signs of upper motor neurons were present in 18, of whom 12 resolved and four had persistent spastic diplegia; 19 had motor delay, of whom 14 resolved; 12 had language delay, of whom 11 resolved; and 16 had impaired brain growth, of whom only five recovered. For the 16 participants already on ART at HIVE diagnosis, regimens were not altered in response to diagnosis.

INTERPRETATION

HIVE may occur despite early ART initiation and virological suppression and then resolve on unchanged ART, most likely as intrathecal inflammation subsides.

WHAT THIS PAPER ADDS

Despite suppressive antiretroviral therapy, children can develop human immunodeficiency virus encephalopathy, The most common manifestations are motor deficits and impaired brain growth. Most experience improvement, with many resolving without additional intervention.

Accelerated aging in perinatally HIV-infected children: clinical manifestations and pathogenetic mechanisms

Background: Premature aging and related diseases have been documented in HIV-infected adults. Data are now emerging also regarding accelerated aging process in HIV-infected children.

Methods: A narrative review was performed searching studies on PubMed published in English language in 2004-2017, using appropriate key words, including “aging”, “children”, “HIV”, “AIDS”, “immunosenescence”, “pathogenesis”, “clinical conditions”.

Results: Premature immunosenescence phenotype of B and T cells in HIV-infected children is mediated through immune system activation and chronic inflammation. Ongoing inflammation processes have been documented by increased levels of pathogen-associated molecular patterns (PAMPS), increased mitochondrial damage, higher levels of pro-inflammatory cytokines, and a positive correlation between sCD14 levels and percentages of activated CD8⁺ cells. Other reported features of premature aging include cellular replicative senescence, linked to an accelerated telomeres shortening. Finally, acceleration of age-associated methylation pattern and other epigenetic modifications have been described in HIV-infected children. All these features may favor the clinical manifestations related to premature aging. Lipid and bone metabolism, cancers, cardiovascular, renal, and neurological systems should be carefully monitored, particularly in children with detectable viremia and/or with CD4/CD8 ratio inversion.

Conclusion: Aging processes in children with HIV infection impact their quality and length of life. Further studies regarding the mechanisms involved in premature aging are needed to search for potential targets of treatment.

Neurodevelopment at 11 months after starting antiretroviral therapy within 3 weeks of life

BACKGROUND

Antiretroviral therapy (ART) started between 7 and 12 weeks of age improves neurodevelopmental outcomes in HIV-infected (HIV+) infants, but the impact of even earlier initiation is not yet described.

OBJECTIVES

We assessed the early neurodevelopment of HIV+ infants who started ART within 21 days of life.

METHOD

Participants were enrolled from the public sector birth HIV-diagnosis programme. Inclusion criteria included the following: birth weight > 2000 g, infant commencing ART < 6 weeks and no infant cytomegalovirus disease. Antiretroviral therapy included Zidovudine/Lamivudine/Nevirapine for the first 2 weeks, the latter then replaced by Lopinavir/Ritonavir. Once body weight > 3 kg and gestational age > 44 weeks, Abacavir replaced Zidovudine. The Griffiths mental development scales (GMDS) were administered at 10-12 months.

RESULTS

Of 29 infants assessed, 23 (79%) were girls. Mean birth weight was 3002 ± 501 g. Twenty-four mothers (83%) received ART during pregnancy. Seven (24%) infants were diagnosed HIV+ within 48 h of birth. Median [interquartile range] viral load (VL) at diagnosis was 3904 [259-16 922] copies/mL, age starting ART was 6.0 [3-10] days and age at VL suppression was 19.1 [15-36] weeks. At the GMDS assessment, nine (31%) participants had detectable VL and 26 (90%) had World Health Organization (WHO) clinical stage I disease. The GMDS was performed at a mean age of 11.5 ± 0.8 months. Mean quotients were within the average range: Global Griffiths score was 103.6 ± 10.9 and mean quotients on the subscales ranged from lowest 95.9 ± 13.4 for locomotor to highest 112.8 ± 11.3 for hearing-and-language.

CONCLUSION

Preliminary findings in this small group suggest that early neurodevelopmental scores are within the normal range in infants with perinatal HIV infection who started ART at a median of 6 days.

Educational delays among children living with perinatally-acquired HIV in Johannesburg, South Africa

Little is known about how growing up with HIV impacts educational outcomes in sub-Saharan African children. We evaluated if South African children living with HIV (CLWH) were in the appropriate school grade-for-age compared to uninfected control children. We observed higher rates of not being in the correct grade-for-age in CLWH compared with controls (OR 3.32, 95% CI: 2.07-5.34), adjusted for study site, sex, whether the child's biological father was alive, and caregiver education. Initiation of ART before 6 months of age reduced but did not eliminate this association. Whether these associations are due to biological factors or other social and environmental determinants, and how best to support CLWH to achieve educational goals, warrants further investigation.

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.

Screening for developmental disabilities in HIV positive and HIV negative children in South Africa: Results from the Asenze Study

Background

While neurodevelopmental abnormalities are common in children with HIV infection, their detection can be challenging in settings with limited availability of health professionals. The aim of this study was to assess the ability to identify developmental disability among HIV positive and HIV negative children living in South Africa with an internationally used screen.

Methods and findings

This analysis uses a sample of 1,330 4–6 year old children and 1,231 of their caregivers in KwaZulu-Natal, South Africa, including administration of the Ten Questions (TQ) screen, a standardized medical history and physical examination conducted by a medical doctor, with hearing and vision screening, psychological assessment for cognition and language delay, and voluntary HIV testing. There was a high prevalence of disability among the sample. Compared to HIV negative children, HIV positive children were more likely to screen positive on at least one TQ item (59.3 vs 42.8%, p = 0.01), be delayed in sitting, standing or walking (OR 3.89, 95% CI = 2.1–7.2) and have difficulty walking or weakness in the arms or legs (OR = 2.7, 95%CI = 0.8–9.37). By medical doctor assessment, HIV positive children were more likely to be diagnosed with gross motor disability (OR = 3.5, 95%CI = 1.3–9.2) and hearing disability (OR = 2.5, 95%CI = 1.2–5.3). By independent psychological assessment, HIV positive children were more likely to have cognitive delay (OR = 2.2, 95%CI = 1.2–3.9) and language delay (OR = 4.3, 95%CI = 2.2–8.4). Among HIV positive children, the sensitivity and specificity of the TQ for serious disability (vs. no disability) was 100% and 51.2%, respectively. Among HIV-negative children, the sensitivity and specificity of the TQ for serious disability (vs. no disability) was 90.2% and 63.9%, respectively.

Conclusions

In this first report of the use of the TQ screen in the isiZulu language, it was found to have high sensitivity for detecting serious developmental disabilities in children, especially HIV positive children. The performance of the TQ in this sample indicates utility for making best use of limited neurodevelopmental resources by screening HIV positive children.

Perinatal HIV Infection or Exposure Is Associated With Low N-Acetylaspartate and Glutamate in Basal Ganglia at Age 9 but Not 7 Years

Abnormalities of the basal ganglia are frequently seen in HIV-infected (HIV+) children despite antiretroviral treatment (ART) initiation during childhood. Assessment of metabolites associated with neuronal integrity or with glial proliferation can present a sensitive description of metabolic events underlying basal ganglia structural changes. We used magnetic resonance spectroscopy to examine differences in creatine, choline, N-acetylaspartate (NAA), glutamate, and myo-inositol between HIV+ children and HIV-unexposed controls, as well as between HIV-exposed uninfected (HEU) children and HIV-unexposed controls at age 7 and at age 9. No differences in metabolites relative to the HIV-unexposed control group were found at age 7. However, at 9 years, both HIV+ and HEU had lower NAA and glutamate than unexposed control children. HEU children also had lower creatine and choline than control children. At age 7, lower CD4/CD8 ratio at enrollment was associated with lower choline levels. At age 9 lower CD4/CD8 at enrollment was associated with lower myo-inositol. Low NAA and glutamate at age 9, but not 7, suggest that basal ganglia neurons may be particularly affected by perinatal HIV/ART and that neuronal damage may be ongoing despite early ART and viral suppression. Reduced basal ganglia metabolite levels in HEU children suggest an effect of HIV exposure on childhood brain development that merits further investigation using neuroimaging and neurocognitive testing.

Altered brain morphometry in 7-year old HIV-infected children on early ART

Even with the increased roll out of combination antiretroviral therapy (cART), paediatric HIV infection is associated with neurodevelopmental delays and neurocognitive deficits that may be accompanied by alterations in brain structure. Few neuroimaging studies have been done in children initiating ART before 2 years of age, and even fewer in children within the critical stage of brain development between 5 and 11 years. We hypothesized that early ART would limit HIV-related brain morphometric deficits at age 7. Study participants were 7-year old HIV-infected (HIV+) children from the Children with HIV Early Antiretroviral Therapy (CHER) trial whose viral loads were supressed at a young age, and age-matched uninfected controls. We used structural magnetic resonance imaging (MRI) and FreeSurfer ( http://www.freesurfer.net/ ) software to investigate effects of HIV and age at ART initiation on cortical thickness, gyrification and regional brain volumes. HIV+ children showed reduced gyrification compared to controls in bilateral medial parietal regions, as well as reduced volumes of the right putamen, left hippocampus, and global white and gray matter and thicker cortex in small lateral occipital region. Earlier ART initiation was associated with lower gyrification and thicker cortex in medial frontal regions. Although early ART appears to preserve cortical thickness and volumes of certain brain structures, HIV infection is nevertheless associated with reduced gyrification in the parietal cortex, and lower putamen and hippocampus volumes. Our results indicate that in early childhood gyrification is more sensitive than cortical thickness to timing of ART initiation. Future work will clarify the implications of these morphometric effects for neuropsychological function.

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.

Larger Subcortical Gray Matter Structures and Smaller Corpora Callosa at Age 5 Years in HIV Infected Children on Early ART

Sub-Saharan Africa is home to 90% of HIV infected (HIV+) children. Since the advent of antiretroviral therapy (ART), HIV/AIDS has transitioned to a chronic condition where central nervous system (CNS) damage may be ongoing. Although, most guidelines recommend early ART to reduce CNS viral reservoirs, the brain may be more vulnerable to potential neurotoxic effects of ART during the rapid development phase in the first years of life. Here we investigate differences in subcortical volumes between 5-year-old HIV+ children who received early ART (before age 18 months) and uninfected children using manual tracing of Magnetic Resonance Images. Participants included 61 Xhosa children (43 HIV+/18 uninfected, mean age = 5.4 ± 0.3 years, 25 male) from the children with HIV early antiretroviral (CHER) trial; 27 children initiated ART before 12 weeks of age (ART-Before12Wks) and 16 after 12 weeks (ART-After12Wks). Structural images were acquired on a 3T Allegra MRI in Cape Town and manually traced using MultiTracer. Volumetric group differences (HIV+ vs. uninfected; ART-Before12Wks vs. ART-After12Wks) were examined for the caudate, nucleus accumbens (NA), putamen (Pu), globus pallidus (GP), and corpus callosum (CC), as well as associations within infected children of structure volumes with age at ART initiation and CD4/CD8 as a proxy for immune health. HIV+ children had significantly larger NA and Pu volumes bilaterally and left GP volumes than controls, whilst CC was smaller. Bilateral Pu was larger in both treatment groups compared to controls, while left GP and bilateral NA were enlarged only in ART-After12Wks children. CC was smaller in both treatment groups compared to controls, and smaller in ART-After12Wks compared to ART-Before12Wks. Within infected children, delayed ART initiation was associated with larger Pu volumes, effects that remained significant when controlling for sex and duration of treatment interruption (left β = 0.447, p = 0.005; right β = 0.325, p = 0.051), and lower CD4/CD8 with larger caudates controlling for sex (left β = -0.471, p = 0.002; right β = -0.440, p = 0.003). Volumetric differences were greater in children who initiated ART after 12 weeks. Results suggest damage is ongoing despite early ART and viral load suppression; however, earlier treatment is neuroprotective.

White Matter Abnormalities in Children with HIV Infection and Exposure

Background: Due to changes in guidelines and access to treatment, more children start combination antiretroviral therapy (ART) in infancy. With few studies examining the long-term effects of perinatal HIV infection and early ART on neurodevelopment, much is still unknown about brain maturation in the presence of HIV and ART. Follow-up studies of HIV infected (HIV+) children are important for monitoring brain development in the presence of HIV infection and ART.

Methods: We use diffusion tensor imaging (DTI) to examine white matter (WM) in 65 HIV+ and 46 control (HIV exposed uninfected (HEU) and HIV unexposed uninfected (HU)) 7-year-old children. This is a follow up of a cohort studied at 5 years, where we previously reported lower fractional anisotropy (FA) in corticospinal tract (CST) and mean diffusivity (MD) increases in inferior/superior longitudinal fasciculi (ILF/SLF), inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus (UF) in HIV+ children compared to uninfected controls. In addition, we also found a difference in FA related to age at which ART was initiated.

Results: At 7 years, we found two regions in the left IFOF and left ILF with lower FA in HIV+ children compared to controls. Higher MD was observed in a similar region in the IFOF, albeit bilaterally, as well as multiple clusters bilaterally in the superior corona radiata (SCR), the anterior thalamic radiation (ATR) and the right forceps minor. Unlike at 5 years, we found no impact on WM of ART initiation. In HEU children, we found a cluster in the right posterior corona radiata with higher FA compared to HU children, while bilateral regions in the CST demonstrated reduced MD.

Conclusions: At age 7, despite early ART and viral load (VL) suppression, we continue to observe differences in WM integrity. WM damage observed at age 5 years persists, and new damage is evident. The continued observation of regions with lower FA and higher MD in HIV+ children point to disruptions in ongoing white matter development regardless of early ART. Lastly, in HEU children we find higher FA and lower MD in clusters in the CST tract suggesting that perinatal HIV/ART exposure has a long-term impact on WM development.

Hippocampal Neuronal Loss in Infant Macaques Orally Infected with Virulent Simian Immunodeficiency Virus (SIV)

The neurological impact of Human Immunodeficiency Virus (HIV) on children includes loss of brain growth, motor abnormalities and cognitive dysfunction. Despite early antiretroviral treatment (ART) intervention to suppress viral load, neurological consequences of perinatal HIV-1 infection persist. Utilizing the pediatric simian immunodeficiency virus (SIV) infection model, we tested the hypothesis that early-life SIV infection depletes neuronal population in the hippocampus. A total of 22 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. We have previously reported that the IV SIVmac251-infected neonatal macaques (Group 1) displayed a 42% neuronal reduction throughout the hippocampal cornu ammonis (CA) fields. The orally-infected infant macaques displayed a 75% neuronal reduction in the CA1 region compared to controls and 54% fewer neurons than IV SIV infants. The CA2 region showed a similar pattern, with a 67% reduction between orally-infected SIV subjects and controls and a 40% difference between IV-and orally-infected SIV groups. In the CA3 region, there were no significant differences between these groups, however both SIV-infected groups had significantly fewer pyramidal neurons than control subjects. There was no correlation between plasma viral load and neuronal populations in any of the CA fields. The loss of hippocampal neurons may contribute to the rapid neurocognitive decline associated with pediatric HIV infection. While each subfield showed vulnerability to SIV infection, the CA1 and CA2 subregions demonstrated a potentially enhanced vulnerability to pediatric SIV infection. These data underscore the need for early diagnosis and treatment, including therapeutics targeting the central nervous system (CNS).

HIV-1 proteins, Tat and gp120, target the developing dopamine system

In 2014, 3.2 million children (< 15 years of age) were estimated to be living with HIV and AIDS worldwide, with the 240,000 newly infected children in the past year, i.e., another child infected approximately every two minutes [1]. The primary mode of HIV infection is through mother-to-child transmission (MTCT), occurring either in utero, intrapartum, or during breastfeeding. The effects of HIV-1 on the central nervous system (CNS) are putatively accepted to be mediated, in part, via viral proteins, such as Tat and gp120. The current review focuses on the targets of HIV-1 proteins during the development of the dopamine (DA) system, which appears to be specifically susceptible in HIV-1-infected children. Collectively, the data suggest that the DA system is a clinically relevant target in chronic HIV-1 infection, is one of the major targets in pediatric HIV-1 CNS infection, and may be specifically susceptible during development. The present review discusses the development of the DA system, follows the possible targets of the HIV-1 proteins during the development of the DA system, and suggests potential therapeutic approaches. By coupling our growing understanding of the development of the CNS with the pronounced age-related differences in disease progression, new light may be shed on the neurological and neurocognitive deficits that follow HIV-1 infection.

The physical and psychological effects of HIV infection and its treatment on perinatally HIV-infected children

INTRODUCTION

As highly active antiretroviral therapy (HAART) transforms human immunodeficiency virus (HIV) into a manageable chronic disease, new challenges are emerging in treating children born with HIV, including a number of risks to their physical and psychological health due to HIV infection and its lifelong treatment.

METHODS

We conducted a literature review to evaluate the evidence on the physical and psychological effects of perinatal HIV (PHIV+) infection and its treatment in the era of HAART, including major chronic comorbidities.

RESULTS AND DISCUSSION

Perinatally infected children face concerning levels of treatment failure and drug resistance, which may hamper their long-term treatment and result in more significant comorbidities. Physical complications from PHIV+ infection and treatment potentially affect all major organ systems. Although treatment with antiretroviral (ARV) therapy has reduced incidence of severe neurocognitive diseases like HIV encephalopathy, perinatally infected children may experience less severe neurocognitive complications related to HIV disease and ARV neurotoxicity. Major metabolic complications include dyslipidaemia and insulin resistance, complications that are associated with both HIV infection and several ARV agents and may significantly affect cardiovascular disease risk with age. Bone abnormalities, particularly amongst children treated with tenofovir, are a concern for perinatally infected children who may be at higher risk for bone fractures and osteoporosis. In many studies, rates of anaemia are significantly higher for HIV-infected children. Renal failure is a significant complication and cause of death amongst perinatally infected children, while new data on sexual and reproductive health suggest that sexually transmitted infections and birth complications may be additional concerns for perinatally infected children in adolescence. Finally, perinatally infected children may face psychological challenges, including higher rates of mental health and behavioural disorders. Existing studies have significant methodological limitations, including small sample sizes, inappropriate control groups and heterogeneous definitions, to name a few.

CONCLUSIONS

Success in treating perinatally HIV-infected children and better understanding of the physical and psychological implications of lifelong HIV infection require that we address a new set of challenges for children. A better understanding of these challenges will guide care providers, researchers and policymakers towards more effective HIV care management for perinatally infected children and their transition to adulthood.

Of mice and monkeys: can animal models be utilized to study neurological consequences of pediatric HIV-1 infection?

Pediatric human immunodeficiency virus (HIV-1) infection remains a global health crisis. Children are much more susceptible to HIV-1 neurological impairments than adults, which can be exacerbated by coinfections. Neurological characteristics of pediatric HIV-1 infection suggest dysfunction in the frontal cortex as well as the hippocampus; limited MRI data indicate global cerebral atrophy, and pathological data suggest accelerated neuronal apoptosis in the cortex. An obstacle to pediatric HIV-1 research is a human representative model system. Host-species specificity of HIV-1 limits the ability to model neurological consequences of pediatric HIV-1 infection in animals. Several models have been proposed including neonatal intracranial injections of HIV-1 viral proteins in rats and perinatal simian immunodeficiency virus (SIV) infection of infant macaques. Nonhuman primate models recapitulate the complexity of pediatric HIV-1 neuropathogenesis while rodent models are able to elucidate the role specific viral proteins exert on neurodevelopment. Nonhuman primate models show similar behavioral and neuropathological characteristics to pediatric HIV-1 infection and offer a stage to investigate early viral mechanisms, latency reservoirs, and therapeutic interventions. Here we review the relative strengths and limitations of pediatric HIV-1 model systems.

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.

Perinatally acquired HIV infection: long-term neuropsychological consequences and challenges ahead

Over the past three decades, perinatal HIV infection in the United States has evolved from a fatal disease to a manageable chronic illness. As the majority of youth with perinatal HIV infection age into adolescence and adulthood, management of this stigmatizing, transmittable disease in the backdrop of a cadre of environmental stressors presents challenges beyond those of other chronic illnesses. The neurologic and neuropsychological consequences of this neurotropic virus have important implications for the successful navigation of responsibilities related to increasingly independent living of this aging population. This article will review the neurologic and neuropsychological consequences of perinatal HIV infection and concomitant factors in the era of highly active antiretroviral therapy and will provide an overview of the neuropathology, pathogenesis, neuroimaging findings, and treatment of perinatal HIV infection, as well as recommendations for service provision and future research.