Predicting HIV disease progression in children using measures of neuropsychological and neurological functioning. Pediatric AIDS clinical trials 152 study team

Body composition, physical fitness and physical activity in Mozambican children and adolescents living with HIV

INTRODUCTION

As a result of the effectiveness of antiretroviral drugs (ART), HIV/AIDS has become a chronic disease, which has enabled children living with HIV to reach adolescence and adulthood. However, the long exposure to both the disease and ART has caused undesirable effects that compromise the physiological functioning and the quality of life of the subjects.

OBJECTIVE

To determine the body composition, physical fitness and habitual physical activity of children and adolescents living with HIV on ART.

METHODS

A total of 79 subjects of both genders aged 8-14 years, living with HIV in ART, selected by convenience participated in the study. The subjects underwent anthropometric assessment, physical fitness assessment and physical activity assessment.

RESULTS

Relative to reference norms, the values of the anthropometric indicators fell below 50th percentile (height/age = 92.4%; BMI/age 72.2%; sum of skinfolds = 51.9%; arm circumference = 63.3%). The prevalence of "low height/age" and "low weight/age" was 34.9% and 9.3%, respectively for boys, and 27.9% and 11.1%, respectively for girls. With the exception of trunk flexibility (12.3%), most subjects were considered unfit in the physical fitness tests (abdominal resistance = 76.4%; handgrip strength = 75.4%; lower limb power = 66.4%). The percentage of subjects with insufficient physical activity was 45.5% for boys and 77.8% for girls. The values for all variables were consistently and significantly lower when compared with studies done in Mozambicans boys and girls without HIV+ from both urban and rural areas.

CONCLUSION

The subjects participants in the study living with HIV and undergoing ART had impaired growth, low physical fitness and low levels of habitual physical activity in relation to the reference values of their peers without HIV, which compromised their physiological functioning and their quality of life.

The Value of a Motor Intervention for 3 to 6-Year-Old Children Infected with and Affected by HIV

Human immunodeficiency virus (HIV)/Aquired Immune Deficiency Syndrome (AIDS) is a large threat to human health and is challenging to address. This study aims to determine if motor intervention is a possibility for promoting the life expectancy and quality of life of children with HIV. The group consisted of 22 participants: 11 HIV-infected (51.73 months, SD 10.15) and 11 HIV-affected children (44.45 months, SD 10.76). A two-group (intervention and control group) pre-test−post-test research design was followed. The HIV-infected and affected children were randomly matched and grouped into an intervention and control group. The intervention group participated in a 12-week motor intervention of 60 min per session, twice per week. The effect of the program was analyzed with regard to motor skills, as established by the PDMS-2 and two strength capabilities. An ANCOVA adjusted for pre-test differences (p < 0.05) indicated statistically significant improvement (p < 0.05) with large practical significance (d > 0.8) in locomotor, fine motor and overall motor skills. The infected children also showed better improvement compared to the affected children. Motor intervention is recommended in the health care path of children affected and infected with HIV, although modifications for improvement of the program are suggested, based on the results attained.

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.

The Brain Retains: Nonhuman Primate Models for Pediatric HIV-1 in the CNS

PURPOSE OF REVIEW

Perinatal HIV-1 infection is associated with an increased risk for neurologic impairments. With limited access to clinical specimens, animal models could advance our understanding of pediatric central nervous system (CNS) disease and viral persistence. Here, we summarize current findings on HIV-1 CNS infection from nonhuman primate (NHP) models and discuss their implications for improving pediatric clinical outcomes.

RECENT FINDINGS

SIV/SHIV can be found in the CNS of infant macaques within 48 h of challenge. Recent studies show an impermeable BBB during SIV infection, suggesting neuroinvasion in post-partum infection is likely not wholly attributed to barrier dysfunction. Histopathological findings reveal dramatic reductions in hippocampal neuronal populations and myelination in infected infant macaques, providing a link for cognitive impairments seen in pediatric cases. Evidence from humans and NHPs support the CNS as a functional latent reservoir, harbored in myeloid cells that may require unique eradication strategies. Studies in NHP models are uncovering early events, causes, and therapeutic targets of CNS disease as well as highlighting the importance of age-specific studies that capture the distinct features of pediatric HIV-1 infection.

HIV-associated neurodevelopmental delay: prevalence, predictors and persistence in relation to antiretroviral therapy initiation and viral suppression

CONTEXT

HIV infection in infancy may influence the developing brain, leading to adverse neurodevelopmental consequences.

OBJECTIVE

We aim to describe neurodevelopmental characteristics of a cohort of HIV-infected infants and young children prior to antiretroviral therapy (ART) initiation and after achieving viral suppression.

METHODS

As part of the Neverest 2 trial, 195 HIV-infected children under 2 years of age were assessed using the Ages and Stages Questionnaire (ASQ) prior to ART initiation and at subsequent age-appropriate time points after ART had been started. The ASQ is a simple screening questionnaire used to identify children at risk of neurodevelopmental delays. Questionnaires completed by the parent/caregiver assess neurodevelopmental functioning in five domains: communication, gross motor, fine motor, problem solving and personal-social.

RESULTS

Median age pre-ART was 8.8 months (range 2.2-24.9) and 53.9% were male. Mean time to viral suppression was 9.4 months (range 5.9-14.5). Compared with pre-ART better outcomes were reported at time of viral suppression with a lower proportion of children failing the gross motor (31.5% vs. 13%, p = 0.0002), fine motor (21.3% vs. 10.2%, p = 0.017), problem solving (26.9% vs. 9.3%, p = 0.0003) and personal-social (19.6% vs. 7.4%, p = 0.019) domains. However, there was no change in the communication domain (14.8% vs. 12.0%, p = 0.6072).

CONCLUSION

Although achieving viral suppression on ART resulted in significant improvements in markers of neurodevelopmental function of young HIV-infected children, potential neurodevelopmental delays still persisted in a large proportion. Further interventions are needed to limit potential disabilities and maximize developmental outcomes.

Multivariable analysis to determine if HIV-1 Tat dicysteine motif is associated with neurodevelopmental delay in HIV-infected children in Malawi

Background

HIV-1 Tat protein is implicated in HIV-neuropathogenesis. Tat C31S polymorphism (Tat^CS) has been associated with milder neuropathology in vitro and in animal models but this has not been addressed in a cohort of HIV-infected adults or children.

Methods

HIV viral load (VL) in plasma and cerebrospinal fluid (CSF) were determined and plasma HIV tat gene was sequenced. Neurodevelopmental assessment was performed using Bayley Scales of Infant Development III (BSID-III), with scores standardized to Malawian norms. The association between Tat^CS and BSID-III scores was evaluated using multivariate linear regression.

Results

Neurodevelopmental assessment and HIV tat genotyping were available for 33 children. Mean age was 19.4 (SD 7.1) months, mean log VL was 5.9 copies/mL (SD 0.1) in plasma and 3.9 copies/mL (SD 0.9) in CSF. The prevalence of Tat^CC was 27 %. Z-scores for BSID-III subtests ranged from −1.3 to −3.9. Tat^CC was not associated with higher BSID-III z-scores.

Conclusions

The hypothesis of milder neuropathology in individuals infected with HIV Tat^CS was not confirmed in this small cohort of Malawian children. Future studies of tat genotype and neurocognitive disorder should be performed using larger sample sizes and investigate if this finding is due to differences in HIV neuropathogenesis between children and adults.

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.

An assessment of WISC-IIIUK on children with HIV infection

The Wechsler Intelligence Scale for Children - Third Edition UK test was administered to groups of children between the ages of 6 and 12 years with vertically transmitted HIV infection (n = 70) and a control group who were not infected by the virus (n = 70). The study was conducted in India. The two groups were matched for general verbal abilities, age and gender. The children were assessed for Verbal IQ, Performance IQ and Full-Scale IQ. The Verbal Comprehension Index, Perceptual Organization Index and Freedom from Distractibility Index were also obtained. A three-factor analysis of variance disclosed that school-age children with vertically transmitted HIV infection notched below in the areas of Verbal IQ, Performance IQ, Full-Scale IQ, Verbal Comprehension Index, Perceptual Organization Index and Freedom from Distractibility Index when collated with normal uninfected cohorts. Findings are discussed in the light of both theoretical and clinical implications.

Clinical associations of white matter damage in cART-treated HIV-positive children in South Africa

A range of factors contributes to white matter damage in vertically infected HIV-positive children. These may include combination antiretroviral treatment (cART) regimen, sociodemographic factors, nutritional-hematological status, HIV-relevant clinical variables, and cognitive functioning. We explored associations between a number of these factors and diffusion tensor imaging (DTI) measures in 50 cART-treated children aged 6 to 15 years. Fractional anisotropy (FA), mean diffusion (MD), radial diffusion (RD), and axial diffusion (AD) were derived from 48 cerebral white matter regions. Significant associations between a number of the clinical variables and white matter integrity were found. Decreased FA, a measure of neuronal damage, was associated with being on second-line cART, low hemoglobin, and younger age. Children with increased MD, a measure of neuronal damage, were younger, had reduced albumin and hemoglobin, and increased viral load. Decreased AD, a measure of axonal damage, was associated with increased viral load and total protein, decreased albumin and hemoglobin, younger age, poorer fronto-striatal cognition, and being on second-line cART. Increased RD, a measure of myelin loss, was associated with younger age, low current CD4 count, low albumin and hemoglobin, and higher viral load and total protein. The current findings underline the possible association of first-line treatment failure with white matter brain dysfunction in pediatric neuroHIV and the importance of examining the effects of HIV disease in the context of treatable clinical variables such as anemia and nutritional status.

Neurologic complications of pediatric human immunodeficiency virus: implications for clinical practice and management challenges in the African setting

Approximately 3.4 million children worldwide are affected with human immunodeficiency virus (HIV)/AIDS with more than 90% of them residing in sub-Saharan Africa, according to the World Health Organization. A significant proportion of the children eligible for treatment with antiretroviral therapy are not currently receiving it. Neurologic manifestations of HIV are common in both adults and children. There is a large spectrum of neurologic conditions that may be caused by the virus; however, early invasion of the central nervous system by the virus, affecting the developing fetal and infant brain, is believed to result in the most common primary HIV-related central nervous system complication, HIV encephalopathy. This article summarizes the spectrum of neuro-HIV in children, focuses on the neurocognitive and behavioral sequelae, reviews the effects of treatment on the primary neurologic effects of the disease, and discusses the specific challenges of identifying and managing these problems in resource-limited contexts, such as those found on the African continent.

A pilot study to investigate the muscle strength of children infected with HIV

Background/aims

Paediatric HIV remains a significant challenge to children and caregivers in South Africa. Little is known about the effect of HIV infection on muscle strength in children, however potential decrease in muscle strength has been inferred to affect functional ability in these children. The aim of this pilot study was to compare the muscle strength of children infected with HIV who had been receiving highly active antiretroviral therapy (HAART) to that of children infected with HIV not receiving HAART.

Methods

The study population included a group of 16 children receiving HAART and 16 children not receiving HAART. A one-off test of muscle strength was undertaken using a hand-held dynamometer for the child, and a demographic questionnaire and social status index to their primary caregiver. Two-sample student t tests, Pearson correlation analyses, and backward regression analyses were used to analyse data.

Results

The cluster of differentiation (CD4) count of the group on HAART was significantly higher than the group not receiving HAART. The group not receiving HAART was stronger than the HAART group. No significant correlation was shown between length of time having received HAART and muscle strength, or between CD4 count and muscle strength in the group receiving HAART. A significant negative correlation was shown between CD4 count and muscle strength in the group not receiving HAART.

Conclusion

Further research is needed to establish the impact of earlier administration of HAART on muscle strength in children infected with HIV.

The neurodevelopment of HIV-infected infants on HAART compared to HIV-exposed but uninfected infants

The aim of this study was to compare the neurodevelopment of HIV-infected (HI) infants in combination with antiretroviral therapy also known as HAART (highly active antiretroviral therapy) to HIV-exposed uninfected (HEU) infants. Twenty-seven HIV infected and 29 HEU infants under the age of one year attending the Empilweni Clinic at Rahima Moosa Mother and Child Hospital were studied. HI infants were assessed prior to initiating HAART and then for six months whilst on HAART. Neurodevelopment was assessed using the Bayley Scales of Infant and Toddler Development, 3rd ed (Bayley III). The HI infants scored significantly lower when compared to HEU infants for motor and language development at baseline, three months and six months follow up. No significant improvement in language (p = 0.46) and motor function (p = 0.91) occurred over time; however, developmental scores did not decrease. Cognitive development in the HI group was significantly lower when compared to the HEU group at visit one (p = 0.003). By six months follow-up, there were no significant differences between the two groups for cognitive development (p = 0.18). This study suggests that HIV-positive infants are delayed when compared to HEU infants. HAART may help to prevent further delay; however, it does not reverse the neurological damage already present. There is a need for therapists to be involved in pediatric HIV clinical services in order to provide early developmental screening as well as rehabilitative services to those children in need.

Validation study of a scale of life quality evaluation in a group of pediatric patients infected by HIV

With the advent of potent antiretroviral therapy and the increase in life expectancy of pediatric patients infected with HIV, the quest for the promotion of enhanced quality of life should currently be the main focus in care of children with HIV/Aids. The scope of this study was to validate the Scale of Children's Quality of Life in a group of children infected with HIV receiving clinical care in Aids Service Units in Rio de Janeiro, Brazil. This scale consists of 26 questions and was tested on 100 children, with ages varying between 4 and 12, and their respective parents or guardians. Statistical analysis was conducted using canonical correlation and confidence interval analysis and the X² test. The results showed that the cut-off point obtained was 49; the internal consistency with Cronbach's alpha was 0.73 for the children and 0.67 for parents or guardians. The response profile revealed marked satisfaction with aspects such as vacations and birthdays, though less satisfaction with items including hospitalization and playing alone. The conclusion was that the scale revealed satisfactory psychometric measurements, proving to be a reliable, consistent, valid and recommended instrument for measuring the quality of life of children infected with HIV.

The effect of a basic home stimulation programme on the development of young children infected with HIV

AIMS

The human immunodeficiency virus (HIV) potentially causes a significant encephalopathy and resultant developmental delay in infected children. The aim of this study was to determine whether a home-based intervention programme could have an impact on the neurodevelopmental status of children infected with HIV.

METHOD

A longitudinal, randomized, controlled trial was conducted. A total of 122 children aged less than 2 years 6 months were assigned to either a comparison or an experimental group. Children in the experimental group were given a home stimulation programme that was updated every 3 months. The home programme included activities to promote motor, cognitive, and speech and language development. Children in the comparison group received no developmental intervention. Children were assessed by a blinded assessor at baseline, 6 months, and 12 months using the Bayley Scales of Infant Development, 2nd edition.

RESULTS

The children in this study came from poor socioeconomic backgrounds and their nutritional status was suboptimal. The experimental group included 60 children (30 males, 30 females) with a mean age of 18 months (SD 8.1 mo). The comparison group included 62 children (32 males, 30 females) with a mean age 19 months (SD 8.2 mo). Cognitive and motor development were severely affected at baseline, with 52% of the children having severe cognitive delay and 72% having severe motor delay at baseline. Children in the experimental group showed significantly greater improvement in cognitive (p=0.010) and motor (p=0.020) development over time than children in the comparison group.

INTERPRETATION

A home stimulation programme taught to the caregiver can significantly improve cognitive and motor development in young children infected with HIV.

The role of weight for age and disease stage in poor psychomotor outcome of HIV-infected children in Kilifi, Kenya

AIM

We aimed to investigate the contribution of disease stage and weight for age to the variability in psychomotor outcome observed among children with human immunodeficiency virus (HIV) infection.

METHOD

This cross-sectional study involved 48 Kenyan children (20 females, 28 males) aged 6 to 35 months (mean 19.9mo SD 8.9) exposed prenatally to HIV. Two subgroups of HIV-exposed children were seen: those who were HIV-infected and those who were uninfected. The reference population was composed of 319 children (159 females, 160 males) aged 6-35 months, (mean age = 19 months, SD=8.43) randomly selected from the community. Disease stage varied from stage 1 to stage 3, reflecting progression from primary HIV infection to advanced HIV infection and acquired immune deficiency syndrome. A locally developed and validated measure, the Kilifi Developmental Inventory, was used to assess psychomotor development.

RESULT

Using age-corrected psychomotor scores, a significant main effect of HIV status was observed (F((2,38.01))=7.89, p<0.001). Children in the HIV-infected group had lower mean psychomotor scores than the HIV-exposed children and the reference group. In the HIV-infected group, disease stage was a negative predictor and weight for age a positive predictor of psychomotor outcome.

INTERPRETATION

Weight for age and disease stage provide viable, easily measurable benchmarks to specify when frequent developmental monitoring and psychomotor rehabilitation are required. Nutritional intervention and other measures aimed at slowing disease progression may delay the onset and severity of psychomotor impairment in the paediatric HIV population in Africa.

Negative life events: risk to health-related quality of life in children and youth with HIV infection

Children and youth with perinatally acquired HIV infection are living longer because of improved drug therapies, but they may be at risk for poor health-related quality of life (HRQOL) outcomes because of nondisease factors. Families affected by HIV disease are more likely to experience major negative life events (NLEs). The effects of NLEs, shown to impact HRQOL in children with other chronic illnesses, have not been evaluated in children with HIV infection. The primary objective of this study was to determine if NLEs occurring in the previous 12 months were associated with increased risk for poorer outcomes in three measures of HRQOL (health perception, behavior problems, and symptom distress) in a cohort of children and youth with HIV infection. The authors conducted a cross-sectional analysis of data determined in 1999 from 1,018 children and youth 5 to 21 years of age enrolled in a longitudinal follow-up study. Multivariate logistic regressions estimated the odds for worse HRQOL outcomes. Children and youth with one or more NLEs had significantly lower health perceptions, more behavior problems, and greater symptom distress than children with no reported NLEs. The occurrence of NLEs may present a significant nondisease risk for diminished HRQOL among children and youth challenged by HIV disease. Nursing efforts to support these younger patients and their families sustaining major family disruption caused by NLEs may improve overall health outcomes in this vulnerable population.

The Pediatric AIDS Severity Score (PASS): a multidimensional AIDS-severity adjustment for pediatric HIV infection

BACKGROUND

A severity staging system predictive of mortality for perinatally HIV-infected children is needed for clinical and research purposes.

METHODS

A pediatric AIDS severity score (PASS) was developed using baseline sociodemographic, clinical, immunologic, and functional measures obtained from 786 perinatally HIV-infected children enrolled into a prospective cohort study (PACTG 219) in the pre-highly active antiretroviral therapy (HAART) era (pre-1996). PASS was then validated among 392 perinatally HIV-infected children randomly sampled from the original source population (n = 1178). Survival estimates and hazard ratios (HRs) were obtained using the Kaplan-Meier method and proportional hazards models, respectively. The most predictive models were determined using Harrell's "C" statistic.

RESULTS

Overall survival was 95% and 90% at 1 and 2 years of follow-up, respectively. The most comprehensive model for predicting mortality, termed the "Full" PASS, included CD4% <15 (HR = 3.9), CDC category C (HR = 2.6), BMI <10% (HR = 2.4), a low (<70) neuropsychological score (HR = 2.6), a general health rating <5 (HR = 2.4), and an elevated symptoms score (HR = 1.9). These determinants were highly predictive of mortality (C statistic = 0.841).

CONCLUSIONS

PASS will be helpful in assessing the effectiveness of ART among children with HIV infection, particularly when randomized clinical trials are not possible due to ethical and feasibility concerns.

Neurologic and neurodevelopmental manifestations of pediatric HIV/AIDS: a global perspective

Neurodevelopmental abnormalities associated with HIV infection have been described since the first reports of pediatric AIDS in the 1980s. Before antiretroviral therapy (ART) became widely available, progressive HIV-1 encephalopathy (PHE) was reported in the US in 13-35% of children with HIV-1 infection and in 35-50% of children with AIDS. Introduction of ART can prevent PHE and reverse PHE present at ART initiation, but a high prevalence of residual problems has been described. Even though 90% of HIV-infected children live in the developing world, few children have access to ART and little is known regarding the neurological manifestations of perinatal HIV infection in those regions. Mechanisms of pediatric HIV-1 neuropathogenesis and factors associated with neurodevelopmental abnormalities in perinatally infected children are not yet fully understood. Studies have demonstrated that HIV-1 enters the CNS soon after infection and may persist in this compartment over the entire course of HIV-1 infection. The CNS is a distinct viral reservoir, differing from peripheral compartments in target cells and antiretroviral penetration. Neurotropic HIV-1 likely develops distinct genotypic characteristics in response to this unique environment. We reviewed the literature on pediatric neuroAIDS and identified gaps in the current knowledge.

Cognitive functioning in school-aged children with vertically acquired HIV infection being treated with highly active antiretroviral therapy (HAART)

In today's era of highly active antiretroviral therapy (HAART), few children with HIV-1 infection experience severe central nervous system (CNS) manifestations indicative of encephalopathy. However, little is known about the neurocognitive strengths and weaknesses of HIV-infected children treated with HAART. This cross-sectional study is the first to systematically investigate the relation between cognitive functioning and medical markers in HIV-infected children and adolescents treated with HAART with varying levels of computed tomography (CT) brain scan abnormalities. The Wechsler Intelligence Scale for Children-Third Edition was administered to 41 vertically infected children (mean age = 11.2 years) treated with HAART for at least 1 year. Other procedures at the time of testing included CT brain scans and collection of CD4 cell counts and plasma HIV1 RNA PCR. Although global cognitive functioning among participants was in the Average range, children with minimal to moderate CT brain scan abnormalities scored significantly lower than children with normal scans on composite measures of cognitive functioning and five specific subtests, especially tasks involving executive functions. Furthermore, children with worse immune status (CD4+ counts < or = 500) scored lower on subtests measuring processing speed. Viral load was unrelated to cognitive test scores. Thus, children with HIV being treated with HAART remain at risk for developing CNS disease. Findings emphasize the importance of conducting neuropsychological assessments in this population, particularly for children with cortical atrophy and absolute CD4+ cell counts < or = 500.

Neurocognitive outcomes in pediatric HIV

Cognitive impairment has long been associated with the natural history of HIV among vertically infected children. In children, HIV may have a direct or indirect impact on the developing brain, may lead to global or highly specific consequences, and may be responsible for minor cognitive consequences or, conversely, long-term and severe disability. This differential impact is related to multiple factors that influence the individual expression of the virus in any given child. This review provides an overview of the relevant literature on neurocognitive outcomes for infants, children, and youth vertically infected with HIV, with attention to those factors impacting neurocognitive outcome within a developmental framework. Research findings in both the era preceding and following the introduction of combined therapies are reviewed, since many of the issues identified prior to state-of-the-art treatment currently available in the United States and other developed countries still apply in much of the developing world. Intervention issues and directions for future research are also discussed.

Cognitive and motor deficits associated with HIV-2(287) infection in infant pigtailed macaques: a nonhuman primate model of pediatric neuro-AIDS

Lentivirus-infected nonhuman primates exhibit behavioral and neurological pathology similar to human immunodeficiency virus (HIV)-infected humans and offer a means to examine the effects of lentivirus infection while controlling for confounding factors inherent in human populations. The purpose of this study was to examine cognitive and motor development in infant macaques vertically infected with HIV-2287. Subjects were 20 infant pigtail macaques (Macaca nemestrina); 8 controls born to uninfected dams, and 12 infants whose dams had been inoculated and infected with HIV-2287 in the third trimester of pregnancy. Eight of these pregnancies had undergone surgical procedures in the form of maternal amniotic catheters or maternal amniotic and fetal carotid artery and jugular vein catheters. Data indicated that catheterization had little or no impact on behavioral development. Seven infants were vertically infected (as measured by polymerase chain reaction (PCR) at birth) and five were not infected (as measured by PCR and coculture on repeated testing). Infected infants attained cognitive and motor milestones at significantly later ages than controls. Uninfected infants, born to infected dams, attained developmental milestones at later ages than controls on all tasks, but this reached statistical significance only for the Fine Motor Task. Attainment of milestones was not correlated with viral dose, maternal CD4+ levels at parturition or infant viral RNA levels at birth. Attainment of milestones was negatively correlated with infants' proportions of CD4+ lymphocytes at birth and significantly correlated with proportions of CD4+ lymphocytes 2 weeks after birth, indicating poorer performance in those infants with a more rapid CD4+ depletion. These cognitive and motor deficits closely resemble those observed in human infants and children infected with HIV and indicate that HIV-2287-infected infant macaques represent an excellent model of pediatric neuro-acquired immunodeficiency syndrome (neuroAIDS).

The impact of neuropsychological impairment and depression on health-related quality of life in HIV-infection

Neuropsychological impairment and depression are common among individual with HIV-infection, resulting in significantly altered everyday functioning. The objective of this study was to examine the impact of these two important neurobehavioural complications on health-related quality of life in adults with HIV-infection. Participants (n = 155) received a 3-hours comprehensive neuropsychological examination, the Beck Depression Inventory, and the Medical Outcomes Study HIV Quality of Life instrument. Four groups were formed based on the presence or absence of depression and neuropsychological impairment. Results suggest that neuropsychological impairment and depression can differentially affect dimensions of health-related quality of Life. Specifically, depression has a significant impact on mental health dimensions of health-related quality of life. Some evidence exists for an impact of neuropsychological impairment, or a combined impact of depression and neuropsychological impairment, on the Physical Health dimensions of health-related quality of life. These results confirm the importance of depression as a determinant of health-related quality of life in HIV/AIDS and provide a potential avenue for improving health-related quality of life in adults with HIV-infection.

Neuropsychological functioning and viral load in stable antiretroviral therapy-experienced HIV-infected children

OBJECTIVE

Neuropsychological functioning and its correlation with viral load were investigated for previously treated HIV-infected children who underwent a change in treatment regimen.

METHODS

Thirteen age-appropriate measures of cognitive, neurologic, and behavioral functioning were administered to 489 HIV-infected children who were aged 4 months to 17 years and had been treated previously for at least 16 weeks with antiretroviral therapy. These clinically and immunologically stable children were randomized onto 1 of 7 drug treatment combinations, 6 of which included a protease inhibitor (PI), and evaluated prospectively for 48 weeks with respect to changes in neuropsychological performance and viral load.

RESULTS

Neuropsychological functioning was significantly poorer at baseline for the HIV-infected children as compared with established norms for their age. Children with higher viral load had poorer cognitive, both-hands fine-motor, and neurologic signs at baseline, but single-hand fine-motor and behavioral functioning were not correlated with viral load. After 48 weeks of treatment with PI-containing combination therapy, there was significant improvement in only the vocabulary score. Neuropsychological changes did not differ among the 6 PI-containing combination regimens. At week 48, even children with a viral load response below the level of detection (RNA < or =400 copies/mL) still showed poorer neuropsychological functioning compared with established norms.

CONCLUSION

Poor neuropsychological functioning was seen for HIV-infected children and was worse for children with higher viral loads. Only 1 measure of neuropsychological functioning showed improvement after treatment with PI-containing combination therapy, and the extent of that improvement was relatively minor. Treatment strategies for children with HIV disease need to be reevaluated so that they consider restoration of neuropsychological functioning in addition to lowering the viral load.

Development of neuronal sensitivity to toxins in cerebrospinal fluid from HIV-type 1-infected individuals

HIV infection of the immature nervous system generally results in a rapid progression of neurological disease that cannot easily be explained by the severity of encephalitis, viral burden, systemic immune deficiency, or developmental changes in utero. Rather than the viral infection dictating disease progression, we explored the possibility that immature neurons might be particularly sensitive to toxins secreted in response to HIV. Primary cultures of rat cortical neurons were exposed to toxic cerebrospinal fluid (CSF) from HIV-infected individuals (CSF(tox)) and evaluated for changes in intracellular calcium and cell death. CSF(tox) had no detectable effect on early neurite outgrowth, calcium regulation, or cell death during the first few days in culture. Starting at Day 4, delayed increases in intracellular calcium appeared in response to CSF(tox). The magnitude of the delayed calcium rise and cell death increased with the age of the culture and correlated with the appearance of synaptophysin immunoreactive varicosities. A similar gradual development of sensitivity was seen during exposure of feline neurons to toxins generated by choroid plexus macrophages after exposure to feline immunodeficiency virus. The possibility that toxin sensitivity is dependent on the presence of synaptic activity is consistent with the rapid pathogenesis in the CNS seen during the first postnatal year. Emerging synaptic activity coupled with other factors such as high metabolic demand in the young nervous system may combine to increase the likelihood of calcium overload and neuronal dysfunction in response to HIV-associated toxins.

Cognitive decline with immunologic and virologic stability in four children with human immunodeficiency virus disease

This case series describes 4 children with vertically acquired human immunodeficiency virus (HIV) infection who exhibited immunologic, virologic, and clinical stability while on a protease inhibitor-containing highly active antiretroviral therapy (HAART) regimen, yet demonstrated significant cognitive decline as measured by standardized intelligence tests. A retrospective review of 107 patient records of children with HIV infection on HAART treatment protocols was conducted. Four patients were identified who responded to protease inhibitor-containing HAART therapy with sustained viral load suppression, and stable immunologic and medical parameters, yet demonstrated significant cognitive decline. Such discordance between biological and clinical markers previously has been reported in adults with HIV disease but not in children. This observed decline in neurocognitive functioning despite stable medical parameters suggests that HAART regimens that are effective for systemic disease may not be as effective for the central nervous system (CNS), perhaps because the antiretrovirals do not penetrate adequately into the CNS. Of note, 3 of these 4 patients did not have zidovudine (ZDV) included in their HAART regimen. The only patient who was treated with ZDV containing regimen received 90 mg/m(2) every 6 hours, which is at the lower end of the recommended ZDV pediatric full-dose range (90 mg/m(2) to 120 mg/m(2)). Two of the 4 patients began ZDV at 120 mg/m(2) every 6 hours following the decline in their cognitive test scores and subsequently showed improved or stable functioning as evidenced by the results of follow-up psychometric testing. Long-term prospective studies using both systemic and CNS measures are necessary to further investigate the effects of HAART in children with HIV disease. Longitudinal cognitive assessments of children receiving HAART appear indicated to identify cognitive decline and to provide appropriate therapeutic intervention when manifestations of HIV-related CNS disease progression occur.

HIV-1 infection and AIDS

Since the initial descriptions of AIDS in the late 1970s, much has been learned about the biology of HIV-1 and the cells it infects. Much has also been learned about mother-to-infant viral transmission and the natural history of HIV-1 infection. Key studies led to strategies for interrupting mother-to-infant transmission, resulting in a significant decline in neonatal HIV-1 infection. More proficient diagnostic techniques made early diagnosis of HIV-1-infected neonates and infants possible during asymptomatic or mildly symptomatic disease stages. Major advances in treatment led to the control of viral replication and thereby altered the course of disease progression. HIV-1/AIDS-associated neurologic disorders declined in parallel. In countries where these therapies are readily available, a dramatic decline in the number of infants born HIV-1 infected has been realized as has a markedly improved survival rate of those infected. Many questions remain, however. The long-term effects of prenatal exposure to antiretroviral agents are not yet known and continue to be studied. Just exactly how HAART therapy may affect early signs of pediatric HIV-1/AIDS-associated CNS disease, should they develop, is unclear. As new anti-retroviral agents are developed and new combination drug regimens are instituted, the potential for neurologic complications, toxicities, and adverse drug interactions (e.g., with antiepileptic drugs (AEDS)) exists and needs to be identified and monitored.