Neurocognitive function in HIV-positive children in a developing country

Prevalence of cognitive impairment in HIV patients: vertical and horizontal transmission

Antiretroviral treatment has significantly increased the survival of patients infected with HIV-1. However, with increased survival, cognitive changes associated with HIV are frequently observed in this population. The clinical manifestations of HIV changes can vary as a result of several aspects, including the virus transmission route. Several studies have pointed out premature neurological changes in vertically infected patients, while the manifestation of cognitive damage in adults may take a longer time.

Objective

The aim of this study was to verify the prevalence of cognitive changes in patients with HIV via vertical transmission after the highly active antiretroviral therapy and the cognitive performance of these patients compared to a group of sexually infected patients.

Methods

A total of 48 patients were evaluated, 25 with vertical transmission and 23 with sexual transmission, between May 2013 and February 2015 at the Institute of infectology Emilio Ribas. Neuropsychological tests were applied to assess cognitive performance, scales to assess symptoms of anxiety and depression, and sociodemographic questionnaire.

Results

The results demonstrate that the frequency of cognitive impairment in vertically transmitted patients was higher than in sexually transmitted patients.

Conclusions

These findings suggest that the deleterious effects of the HIV virus on the development of the central nervous system reverberate more strongly than in patients who acquire it after adulthood.

HIV Encephalopathy in ART-Naïve, Hospitalized Infants in Mozambique

INTRODUCTION

The neurodevelopmental impact of HIV infection in older children has been well-described, with characterization of HIV-associated encephalopathy (HIVE) and associated cognitive defects. HIVE is relatively common in older children who were vertically infected. The sparse literature on HIVE in infants suggests that incidence may be up to 10% in the first year of life, but no studies were identified that specifically evaluated hospitalized infants.

METHODS

A descriptive study of routine inpatient data from two central referral hospitals in Mozambique was conducted. Inclusion criteria were infants with confirmed HIV infection aged <12 months, not on ART, admitted between 1 January 2019 and 30 June 2019. Presumptive HIVE was defined as having delayed developmental milestones in addition to microcephaly and/or pathological reflexes.

RESULTS

Seven out of 27 patients (26%) were classified as presumptive HIVE. Delayed milestones were seen in 18 patients (67%) and the prevalence was approximately two times higher in the HIVE (+) group across all milestone categories. Delayed or no maternal ART (p = 0.03) and the infant not having received postnatal nevirapine prophylaxis (p = 0.02) were significantly associated with HIVE.

CONCLUSIONS

HIVE prevalence is high in ART naïve hospitalized infants, particularly in those with risk factors for in-utero transmission. Thorough neurologic and developmental assessments can help identify HIV-infected infants and can be of particular utility in pediatric wards without access to point-of-care virologic testing where presumptive HIV diagnosis is still needed. Infants with HIVE need comprehensive care that includes antiretroviral therapy and physical/occupational therapy.

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.

Neurocognitive Lag in School-Aged Children Living With HIV in India and Its Relevance

Objective

Objective assessment of neurocognitive lags in pediatric HIV patients and its correlation with various clinical, social and familial factors.

Methods

Ninety-eight school-aged children living with HIV (CLHIV) (age 7-18 years) attending regional pediatric HIV clinic were observed for neurocognitive lag using Raven’s Standard Progressive Matrices by the same trained instructor. Sociodemographic data, mode of transmission, clinical staging, CD4 count, highly active antiretroviral therapy (HAART) duration were recorded and analyzed in the well-performing group and under-performing group.

Results

29.6% of children had definitive neurocognitive lag. The proportion of older children (11-18 years) in the under-performing group was significantly high (P = 0.007). The mean CD4 counts were low in the under-performing group (P = 0.001). Other socioeconomic factors could not be specifically correlated with neurocognitive lag in either of the groups.

Conclusion

CLHIV has a significant neurocognitive lag, which is accentuated in the upper age group. Findings point toward declining intellectual gains with increasing age in CLHIV.

Cognitive outcomes at ages seven and nine years in South African children from the children with HIV early antiretroviral (CHER) trial: a longitudinal investigation

INTRODUCTION

Many children living with HIV (CLWH) display impaired cognition. Although early combination antiretroviral therapy (ART) produces improved cognitive outcomes, more long-term outcome data are needed. After concluding the Children with HIV Early antiRetroviral (CHER) trial in 2011, we investigated cognitive performance, at seven and nine years of age. Participants had been randomized to deferred ART (ART-Def; n = 22); immediate time-limited ART for 40 weeks (ART-40W; n = 30) and immediate time-limited ART for 96 weeks (ART-96W; n = 18). We also recruited HIV-exposed uninfected (CHEU; n = 28) and HIV-unexposed (CHU; n = 35) children.

METHODS

Data were collected between May 2012 and December 2017. Mixed-model repeated-measures ANOVAs assessed differences over time between CLWH (ART-40W, ART-96W and ART-Def) and CHIV- CHEU and CHU between ART-Early (ART-40W and ART-96W), ART-Def, CHEU and CHU; and between ART-40W, ART-96W, ART-Def, CHEU and CHU.

RESULTS

All comparisons found significant effects of Time for most outcome variables (better scores at nine than at seven years; ps < 0.05). The first ANOVAs found that for (a) motor dexterity, CLWH performed worse than CHIV- at seven years (p < 0.001) but improved to equivalence at nine years, (b) visual-spatial processing and problem solving, only CLWH (p < 0.04) showed significant performance improvement over time and (c) working memory and executive function, CLWH performed worse than CHIV- at both seven and nine years (p = 0.03 and 0.04). The second ANOVAs found that for (a) working memory, CHU performed better than ART-Early and CHEU (p < 0.01 and <0.04), and (b) motor dexterity, ART-Def performed worse than ART-Early, CHEU and CHU at seven years (p = 0.02, <0.001 and <0.001 respectively) but improved to equivalence at nine years (ps > 0.17). Similarly, for motor dexterity, ART-Def performed worse than ART-96W, CHEU and CHU at seven years (p < 0.04, <0.001 and <0.001) but improved to equivalence at nine years (ps > 0.20).

CONCLUSIONS

Although neurocognitive developmental trajectories for treatment groups and controls were largely similar (i.e. performance improvements from 7 to 9), all ART-treated children, regardless of treatment arm, remain at risk for cognitive deficits over early school ages. Although the nature of these deficits may change as cognitive development proceeds, there are potential negative consequences for these children's future learning, reasoning and adaptive functioning.

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.

Development of a computerised neurocognitive battery for children and adolescents with HIV in Botswana: study design and protocol for the Ntemoga study

INTRODUCTION

Neurodevelopmental delays and cognitive impairments are common in youth living with HIV. Unfortunately, in resource-limited settings, where HIV infection impacts millions of children, cognitive and neurodevelopmental disorders commonly go undetected because of a lack of appropriate assessment instruments and local expertise. Here, we present a protocol to culturally adapt and validate the Penn Computerized Neurocognitive Battery (PennCNB) and examine its validity for detecting both advanced and subtle neurodevelopmental problems among school-aged children affected by HIV in resource-limited settings.

METHODS AND ANALYSIS

This is a prospective, observational cohort study. The venue for this study is Gaborone, Botswana, a resource-limited setting with high rates of perinatal exposure to HIV and limited neurocognitive assessment tools and expertise. We aim to validate the PennCNB in this setting by culturally adapting and then administering the adapted version of the battery to 200 HIV-infected, 200 HIV-exposed uninfected and 240 HIV-unexposed uninfected children. A series of analyses will be conducted to examine the reliability and construct validity of the PennCNB in these populations.

ETHICS AND DISSEMINATION

This project received ethical approval from local and university Institutional Review Boards and involved extensive input from local stakeholders. If successful, the proposed tools will provide practical screening and streamlined, comprehensive assessments that could be implemented in resource-limited settings to identify children with cognitive deficits within programmes focused on the care and treatment of children affected by HIV. The utility of such assessments could also extend beyond children affected by HIV, increasing general access to paediatric cognitive assessments in resource-limited settings.

Late diagnosis of human immunodeficiency virus infection is linked to higher rates of epilepsy in children in the Eastern Cape of South Africa

BACKGROUND

Human immunodeficiency virus (HIV)-positive children may present with a wide range of neurological disorders. Among these, epilepsy is of key concern because of its lifelong impact and potential for damage to the central nervous system (CNS). Few studies in developing regions have investigated the prevalence and aetiology of epilepsy in HIV-infected children as a key population.

OBJECTIVES

We describe the prevalence of epilepsy, associated neurological disabilities, immunological status, clinical stage and history of CNS infection at epilepsy diagnosis in a cohort of HIV-infected children receiving antiretroviral therapy (ART) in the Eastern Cape of South Africa.

METHODS

We conducted a retrospective study (2004-2014) at two major referral sites for HIV-infected children diagnosed with epilepsy aged 0-16 years. Eligible subjects were extracted from the electronic medicine bridging access to care in excellence (EMBRACE) Paediatric Cohort using the Paediatric ART Data Management Tool (PADMT). Fixed data fields were interrogated for exposures to antiepileptic drugs. Unstructured 'comments' fields were searched for the terms: epilepsy, seizures, fits and szs, as well as abbreviated versions of common antiepileptic drug names. Eligible subject folders were then retrieved to validate the digital data.

RESULTS

From 2139 children enrolled in the two sites, 53 children were diagnosed with epilepsy (2.48%). In these, the median CD4 count was 591 cells/mm3, and the mean viral load was 4.9 log copies/mL, with undetectable viral loads in only seven children (14.0%). World Health Organization (WHO) clinical HIV stage was available for 46 patients of the sample, with 3, 6, 26 and 11 children graded at stages 1, 2, 3 and 4, respectively. Forty percent children had a history of CNS infection prior to the epilepsy diagnosis, and 55% children were reported to have school problems.

CONCLUSIONS

In this descriptive study, the prevalence of epilepsy among children with HIV was 2.48%, mostly diagnosed in advanced HIV-disease stages. Our findings support the usefulness of early detection and initiation of ART in HIV-infected children in order to reduce the risk of epilepsy. In addition, our study demonstrates that novel techniques are effective in accessing cohort-level data that allow interrogation of both structured and unstructured clinical data.

Dose-dependent neurocognitive deficits following postnatal day 10 HIV-1 viral protein exposure: Relationship to hippocampal anatomy parameters

Despite the availability of antiretroviral prophylactic treatment, pediatric human immunodeficiency virus type 1 (HIV-1) continues to be a significant risk factor in the post-cART era. The time of infection (i.e., during pregnancy, delivery or breastfeeding) may play a role in the development of neurocognitive deficits in pediatric HIV-1. HIV-1 viral protein exposure on postnatal day (P)1, preceding the postnatal brain growth spurt in rats, had deleterious effects on neurocognitive development and anatomical parameters of the hippocampus (Fitting et al., 2008a,b). In the present study, rats were stereotaxically injected with HIV-1 viral proteins, including Tat1-86 and gp120, on P10 to further examine the role of timing on neurocognitive development and anatomical parameters of the hippocampus (Fitting et al., 2010). The dose-dependent virotoxin effects observed across development following P10 Tat1-86 exposure were specific to spatial learning and absent from prepulse inhibition and locomotor activity. A relationship between alterations in spatial learning and/or memory and hippocampal anatomical parameters was noted. Specifically, the estimated number of neurons and astrocytes in the hilus of the dentate gyrus explained 70% of the variance of search behavior in Morris water maze acquisition training for adolescents and 65% of the variance for adults; a brain-behavior relationship consistent with observations following P1 viral protein exposure. Collectively, late viral protein exposure (P10) results in selective alterations in neurocognitive development without modifying measures of somatic growth, preattentive processing, or locomotor activity, as characterized by early viral protein exposure (P1). Thus, timing may be a critical factor in disease progression, with children infected with HIV earlier in life being more vulnerable to CNS disease.

Early Sites of Virus Replication After Oral SIVmac251 Infection of Infant Macaques: Implications for Pathogenesis

Despite optimization of preventative measures for vertical HIV-1 transmission, daily, roughly 400 infants become HIV infected, most of them through breastfeeding. Viral entry has been presumed to occur in the gastrointestinal tract; however, the exact entry site(s) have not been defined. Therefore, we quantified simian immunodeficiency virus (SIV) RNA and DNA in oral, intestinal, and systemic tissues of 15 infant macaques within 48-96 h after oral SIV_mac251 exposure. SIV DNA was detected as early as 48 h, whereas SIV RNA was typically detected at later time points (72-96 h). Transmitted founder viruses were identical or very similar to a single genotype in the SIV_mac251 challenge stock. SIV RNA and DNA were most frequently found in lymph nodes (LNs) draining the oral cavity and in the ileum. Using in situ hybridization, SIV-infected cells in LNs were exclusively represented by CD3⁺ T cells. SIV RNA and DNA were also detected in the lungs of 20% of the animals, and 60% of the animals had detectable SIV DNA in the cerebrum. The early detection of viral RNA or DNA in lung and brain tissues emphasizes the need for early treatment of pediatric HIV infection to prevent damage not only to the immune system but also to the respiratory tract and central nervous system.

Neurocognitive development in HIV-positive children is correlated with plasma viral loads in early childhood

Because of neurocognitive impairments in perinatally human immunodeficiency virus (HIV)-infected children and adolescents, this study aimed to demonstrate the effect of plasma viral loads and early initiation of sufficient combined antiretroviral therapy (cART) on neurocognitive development.In total, 14 perinatally infected HIV-positive children (median age 8.24 years [range: 6.0-16.74]) receiving lopinavir/ritonavir (LPV/r)-based ART underwent neurocognitive testing using the Wechsler Intelligence Score for Children, 4th Edition (WISC-IV). All 14 patients participated in a pharmacokinetic study in which they were hospitalized for an entire day. As a child's ability to concentrate varies over the course of the day, all tests were performed in the morning.The patients' neurocognitive development did not significantly differ from the normative collective pattern for any of the following composite scores that were examined: full-scale intelligence quotient (IQ) (mean: 106.5, P = .1060), verbal comprehension index (mean: 106.0, P = .1356), perceptual reasoning index (mean: 106.0, P = .1357), working memory index (mean: 106.3, P = .1171), and processing speed index (mean: 98.1, P = .6313). The overall full-scale IQ scores were significantly higher in children who began ART within the first year of life (P = .0379), whereas low lopinavir/r plasma levels (P = .0070) and high viral load area under the curves (AUCs) in the first 3 years of life, but not later, significantly correlated with reduced neurocognitive performance (Spearman r = -0.64, P = .0278).In this cohort of cART treated HIV-positive children and adolescents, neurocognitive performance correlated with early and sufficient viral load suppression within the first 3 years of life.

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-Associated Cognitive Impairment in Perinatally Infected Children: A Meta-analysis

CONTEXT

Research shows, conclusively, that perinatal HIV infection has negative effects on cognitive functioning of children and adolescents. However, the extent of these cognitive impairments is unknown. Current literature does not document specific cognitive domains most affected in HIV-infected children and adolescents.

OBJECTIVE

To systematically review and meta-analyze the degree of cognitive impairment, and the specific cognitive domains affected, in children and adolescents with perinatally acquired HIV infection.

DATA SOURCES

We systematically searched 5 electronic bibliographic databases, namely: PubMed, PsychINFO, Academic Search Premier, Scopus, and WorldCat, by using a search protocol specifically designed for this study.

STUDY SELECTION

Studies were selected on the basis of set a priori eligibility criteria. Titles, abstracts, and full texts were assessed by 2 independent reviewers.

DATA EXTRACTION

Data from included studies were extracted into Microsoft Excel by 2 independent reviewers.

RESULTS

Twenty-two studies were identified for inclusion in the systematic review and of this, 6 studies were included in the meta-analysis. Results from the meta-analysis indicated that working memory and executive function were the domains most affected by the HIV virus.

LIMITATIONS

Only 27% of the included studies were suitable to enter into the meta-analysis. There was significant geographic bias in published studies, with only 32% (7/22) of included studies from sub-Saharan Africa.

CONCLUSIONS

The evidence supports an association between HIV infection in children and adolescents and cognitive impairment in the domains of working memory, executive function and processing speed, with effect size estimates also providing some support for deficits in visual memory and visual-spatial ability.

Selective developmental alterations in The HIV-1 transgenic rat: Opportunities for diagnosis of pediatric HIV-1

Since the advent of combination antiretroviral therapy (cART), pediatric HIV-1 (PHIV) has evolved from a fatal disease to a chronic disease as children perinatally infected with HIV-1 survive into adulthood. The HIV-1 transgenic (Tg) rat, which expresses 7 of the 9 HIV-1 genes constitutively throughout development, was used to model the early development of chronic neurological impairment in PHIV. Male and female Fischer HIV-1 Tg and F344 N control rats, sampled from 35 litters, were repeatedly assessed during early development using multiple experimental paradigms, including somatic growth, locomotor activity, cross-modal prepulse inhibition (PPI) and gap-prepulse inhibition (gap-PPI). Later eye opening was observed in HIV-1 Tg animals relative to controls. HIV-1 Tg animals exhibited a shift in the development of locomotor activity implicating alterations in the maturation of the forebrain cholinergic inhibitory system. Alterations in the development of PPI and perceptual sharpening were observed in both auditory and visual PPI as indexed by a relative insensitivity to the dimension of time (msec for ISI; days of age for perceptual sharpening) as a function of the HIV-1 transgene. Presence of the HIV-1 transgene was diagnosed with 97.1 % accuracy using auditory and visual PPI measurements from PD 17 and 21. Early selective developmental alterations observed in the HIV-1 Tg rats provide an opportunity for the development of a point-of-care screening tool, which would permit the early diagnosis of PHIV and improve the long-term outcome for children perinatally infected with HIV-1.

Neurocognition and quality of life after reinitiating antiretroviral therapy in children randomized to planned treatment interruption

OBJECTIVE

Understanding the effects of antiretroviral treatment (ART) interruption on neurocognition and quality of life (QoL) are important for managing unplanned interruptions and planned interruptions in HIV cure research.

DESIGN

Children previously randomized to continuous (continuous ART, n = 41) vs. planned treatment interruption (PTI, n = 47) in the Pediatric European Network for Treatment of AIDS (PENTA) 11 study were enrolled. At study end, PTI children resumed ART. At 1 and 2 years following study end, children were assessed by the coding, symbol search and digit span subtests of Wechsler Intelligence Scale for Children (6-16 years old) or Wechsler Adult Intelligence Scale (≥17 years old) and by Pediatrics QoL questionnaires for physical and psychological QoL. Transformed scaled scores for neurocognition and mean standardized scores for QoL were compared between arms by t-test and Mann-Whitney U test, respectively. Scores indicating clinical concern were compared (<7 for neurocognition and <70 for QoL tests).

RESULTS

Characteristics were similar between arms with a median age of 12.6 years, CD4⁺ of 830 cells/μl and HIV RNA of 1.7 log10copies/ml. The median cumulative ART exposure was 9.6 in continuous ART vs. 7.7 years in PTI (P = 0.02). PTI children had a median of 12 months off ART and had resumed ART for 25.2 months at time of first assessment. Neurocognitive scores were similar between arms for all tests. Physical and psychological QoL scores were no different. About 40% had low neurocognitive and QoL scores indicating clinical concern.

CONCLUSION

No differences in information processing speed, sustained attention, short-term memory and QoL functioning were observed between children previously randomized to continuous ART vs. PTI in the PENTA 11 trial.

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.