Neurodevelopment, growth, and viral load in HIV-infected infants

Growth Faltering and Developmental Delay in HIV-Exposed Uninfected Ugandan Infants: A Prospective Cohort Study

BACKGROUND

HIV-exposed but uninfected (HEU) infants are at increased risk of impaired early linear growth and cognitive development. We examined associations between prenatal and postnatal growth and subsequent neurodevelopment in Ugandan HEU infants, hypothesizing that early insults may explain alterations in both somatic growth and brain development.

METHODS

We prospectively followed a cohort of HEU infants from birth to 18 months of age, and measured length/height, weight, head, and arm circumference longitudinally. The Malawi Development Assessment Tool (MDAT, 12 and 18 months) and the Color Object Association Test (18 months) were used for developmental assessments.

RESULTS

Among 170 HEU infants, the prevalence of low-birth weight and failure to thrive was 7.6% and 37%, respectively. HEU infants had MDAT scores that were similar to the reference population. The mean (SD) score on the Color Object Association Test was 5.5 (3.1) compared with 6.9 (5.3) in developmentally normal children. Developmental ability at age 18 months showed strong cross-sectional correlation with weight-for-age (ρ = 0.36, P < 0.0001), length/height-for-age (ρ = 0.41, P < 0.0001), head circumference-for-age (ρ = 0.26, P = 0.0011), and mid-upper arm circumference-for-age (ρ = 0.34, P = 0.0014). There was a statistically significant correlation between birth weight and MDAT z-score at 18 months (ρ = 0.20, P = 0.010). Failure to thrive was associated with lower MDAT z-score [median -0.13 (IQR -0.75 to +0.14) versus +0.14 (IQR -0.44 to +0.63), P = 0.042].

CONCLUSION

Growth faltering in HEU infants was associated with lower attainment of developmental milestones at age 18 months. Our findings point to a simple screening method for identifying HEU infants at risk for developmental intervention.

The effect of HIV infection and exposure on cognitive development in the first two years of life in Malawi

OBJECTIVES

To assess longitudinal patterns and determinants of cognitive development in infants living with HIV, infants exposed to maternal HIV infection, and HIV-unexposed infants.

METHODS

Prospective, community-based cohort study of 555 Malawian infants aged 8 weeks to 24 months, using multivariable linear mixed-effects regression models with random intercepts to analyze repeated measures of cognitive function.

RESULTS

At 3 months of age, cognitive scores on the Bayley Scales of Infant Development (BSID 3rd edition) were lower in the 96 HIV-infected infants (mean = 14.1 (SD:4.8)) compared to the 289 HIV-exposed (mean = 16.5 (SD:3.7)) and the 170 unexposed infants (mean = 17.5 (SD:3.3)). Over the first two years of life, the small deficit in cognitive development of infants living with HIV who survived and remained in care did not increase (mean score 52.9 among HIV-infected vs 55.6 among HIV unexposed). In multivariable analysis, malnutrition and a more advanced clinical infant HIV stage had a negative impact on cognition at age 3, while financial security, care by the biological mother, and ART for mother and child were associated with better cognitive status at this young age. The positive influence of maternal ART reversed with age.

CONCLUSIONS

Malawian infants exposed to HIV had a cognitive development that was similar to their unexposed peers in the first two years of life, while that of HIV infected infants lagged behind from the start. Early initiation of effective ART in all HIV infected mothers and infants, and prevention of infant malnutrition are important to safeguard cognitive development of children affected by HIV.

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.

Neurodevelopment in Young Children Born to HIV-Infected Mothers: A Meta-analysis

CONTEXT

HIV-infected (HIV+) children have worse neurodevelopmental outcomes compared with HIV-uninfected children. However, little is known regarding the differences in neurodevelopment between young HIV+ children, HIV-exposed but uninfected (HEU) children, and HIV-unexposed and uninfected (HUU) children.

OBJECTIVE

To systematically review and meta-analyze data on neurodevelopmental performance between young HIV+, HEU, and HUU children.

DATA SOURCES

We systematically searched the following electronic bibliographic databases: Ovid Medline, Embase, PsycINFO, Education Resources Information Center, and the Cochrane Database of Systematic Reviews.

STUDY SELECTION

Studies were selected on the basis of defined inclusion criteria. Titles, abstracts, and full texts were assessed by 2 independent reviewers.

DATA EXTRACTION

Data were extracted by 2 independent reviewers and cross-checked by 2 additional reviewers.

RESULTS

Forty-five studies were identified for inclusion in the systematic review, and of these, 11 were included in the meta-analysis on the basis of availability of Bayley Scales of Infant and Toddler Development scores. Within the meta-analysis, when compared with their HUU peers, HIV+ and HEU children had lower cognitive and motor scores. HIV+ and HEU children with antiretroviral (ARV) exposure had lower cognitive and motor scores compared with those without ARV exposure.

LIMITATIONS

We were unable to control adequately for intravenous drug use, geographic location, or quality of the assessment independently.

CONCLUSIONS

Both HIV+ and HEU children had worse developmental outcomes compared with HUU children. HIV+ and HEU children with ARV exposure also had worse developmental outcomes compared with those without exposure; however, these results should be interpreted with caution. More research is needed to identify the impact of ARV exposure on young children.

Working Memory Profiles in HIV-Exposed, Uninfected and HIV-Infected Children: A Comparison with Neurotypical Controls

This study compared the working memory profiles of three groups of children, namely HIV-infected (HIV-I; n = 95), HIV-exposed, uninfected (HIV-EU; n = 86) and an HIV-unexposed, uninfected, (HIV-UU; n = 92) neurotypical control group. Working memory, an executive function, plays an important role in frontal lobe-controlled behaviors, such as motivation, planning, decision making, and social interaction, and is a strong predictor of academic success in school children. Memory impairments have been identified in HIV-I children, particularly in visuospatial processing. Verbal working memory has not been commonly investigated in this population, while it is unknown how the working memory profiles of HIV-EU children compare to their HIV-I and HIV-UU peers. Of interest was whether the working memory profiles of the HIV-EU children would be more similar to the HIV-I group or to the uninfected control group. The results revealed no significant differences in working memory performance between the HIV-I and HIV-EU groups. However, this does not mean that the etiology of the working memory deficits is the same in the two groups, as these groups showed important differences when compared to the control group. In comparison to the controls, the HIV-I group experienced difficulties with processing tasks irrespective of whether they drew on a verbal or visuospatial modality. This appears to stem from a generalized executive function deficit that also interferes with working memory. In the HIV-EU group, difficulties occurred with verbally based tasks, irrespective of whether they required storage or processing. For this group, the dual demands of complex processing and using a second language seem to result in demand exceeding capacity on verbal tasks. Both groups experienced the greatest difficulties with verbal processing tasks for these different reasons. Thus, disruption of different cognitive abilities could result in similar working memory profiles, as evidenced in this study. This has implications for the underlying developmental neurobiology of HIV-I and HIV-EU children, as well the choice of appropriate measures to assist affected children.

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).

Delayed tooth emergence in children infected with human immunodeficiency virus

OBJECTIVE

There is limited evidence that early deficits in growth might be reflected in tooth emergence in children infected with human immunodeficiency virus (HIV). The purpose of this study was to prospectively evaluate tooth emergence timing between children positive and negative for HIV in the exposed and unexposed groups, respectively.

STUDY DESIGN

A longitudinal study of children positive for HIV and HIV-negative household peers, aged 2 to 15 years was conducted between 1993 and 1996. Emergence status was determined for the maxillary and the mandibular permanent first molars and the central and lateral incisors. A multivariable, discrete time, proportional hazards model was fitted to the data. Median age of emergence for each of the six pairs of teeth was calculated using the parameter estimates from the regression model.

RESULTS

A total of 116 participants (62 HIV positive, 54 HIV negative) completed six examinations over the 36-month study period. Statistical differences in tooth emergence timing were observed for five of the six tooth pairs, with children positive for HIV being less likely to have emergence of the corresponding tooth compared with the children negative for HIV. Age differences for each tooth pair ranged from 0.7 to 1.5 years, with a median emergence age difference of 1.03 years.

CONCLUSIONS

Delayed tooth emergence of the permanent dentition was observed in children with HIV.

Correlates of age at attainment of developmental milestones in HIV-infected infants receiving early antiretroviral therapy

BACKGROUND

Infant HIV-1 infection is associated with impaired neurologic and motor development. Antiretroviral therapy (ART) has the potential to improve developmental outcomes but the relative contributions of pre-ART disease status, growth, treatment regimen and ART response during infancy are unknown.

METHODS

Kenyan ART-naive infants <5-months old initiated ART and had monthly assessment of age of full neck control, unsupported walking and monosyllabic speech during 24 months of follow-up. Pre-ART and post-ART correlates of age at milestone attainment were evaluated using t tests or multivariate linear regression.

RESULTS

Among 99 infants, pre-ART correlates of later milestone attainment included: underweight and stunted (neck control, walking and speech, all P values <0.05), missed prevention of mother-to-child transmission (P = 0.04) (neck control), previous hospitalization, World Health Organization (WHO) Stage III/IV, low CD4 count, and wasting (speech and walking, all P values <0.05), and low maternal CD4 (speech, P = 0.04). Infants initiated ART at a median of 14 days following enrollment. Infants receiving nevirapinevs lopinavir/ritonavir-based ART attained later speech (18.1 vs. 15.5 months, P = 0.003) [corrected]. Adjusting for pre-ART level, lower 6-month gain in CD4% was associated with later walking (0.18 months earlier per unit increase in CD4%; P = 0.004) and speech (0.12 months earlier per unit increase in CD4%; P = 0.05), and lower 6-month gains in weight-for-age (P = 0.009), height-for-age (P = 0.03) and weight-for-height (P = 0.02) were associated with later walking.

CONCLUSION

In HIV-infected infants, compromised pre-ART immune and growth status, poor post-ART immune and growth responses, and use of nevirapine- vs. lopinavir/ritonavir-based ART were each associated with later milestone attainment [corrected]. The long-term consequences of these delays are unknown.

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.

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.

Neurodevelopment in children born to HIV-infected mothers by infection and treatment status

BACKGROUND

We reviewed the impact of HIV, HIV exposure, and antiretroviral therapy/prophylaxis on neurodevelopmental outcomes of HIV-infected and HIV-exposed-uninfected infants and children.

METHODS

A literature search of Medline, Embase, PsychINFO, Web of Science, PubMed, and conference Web sites (1990-March 2011) using the search terms, infant, child, HIV, neurodevelopment, cognition, language, and antiretroviral therapy, identified 31 studies of HIV/antiretroviral exposure using standardized tools to evaluate infant/child development as the main outcome. Articles were included if results were reported in children <16 years of age who were exposed to HIV and antiretrovirals in fetal/early life, and excluded if children did not acquire HIV from their mothers or were not exposed to antiretrovirals in fetal/early life.

RESULTS

Infants who acquired HIV during fetal and early life tended to display poorer mean developmental scores than HIV-unexposed children. Mean motor and cognitive scores were consistently 1 to 2 SDs below the population mean. Mean scores improved if the infant received treatment before 12 weeks and/or a more complex antiretroviral regimen. Older HIV-infected children treated with highly active antiretroviral therapy demonstrated near normal global mean neurocognitive scores; subtle differences in language, memory, and behavior remained. HIV-exposed-uninfected children treated with antiretrovirals demonstrated subtle speech and language delay, although not universally.

CONCLUSIONS

In comparison with resource-rich settings, HIV-infected and HIV-exposed-uninfected infants/children in resource-poor settings demonstrated greater neurodevelopmental delay compared with HIV-unexposed infants. The effects on neurodevelopment in older HIV-infected children commenced on antiretroviral therapy from an early age and HIV-exposed-uninfected children particularly in resource-poor settings remain unclear.

Outcome of HIV exposed infants: experience of a regional pediatric center for HIV in North India

OBJECTIVE

To study the outcome of HIV exposed infants in terms of mortality, morbidity, nutritional status and HIV infection status.

METHODS

Retrospective analysis of data on 162 HIV exposed infants registered at Regional Pediatric Center for HIV, Delhi and meeting the inclusion criteria, was done.

RESULTS

Median age at presentation was 6 wk. 17.4% mothers were on ART while 44.1% received NVP prophylaxis. 61.7% babies received NVP prophylaxis. Thirty-three percent of infants were symptomatic at presentation. Feeding strategy followed was breast-feeding in 18.7%, replacement feeding 71.6% and mixed feeding 9.7%. At presentation, 50.6% infants were wasted, 48.8% stunted and 39.4% had microcephaly. A progressive increase in proportion of children with under-nutrition, stunting and microcephaly was noted with increasing age at presentation. Of the enrolled infants, 81 (50%) were alive and under follow-up. Among these, HIV infection was excluded in 65 infants (80.2% of those alive, 40.1% of the cohort). Thirty-four (21%) infants died and 47 (29%) were lost to follow-up. HIV infection was diagnosed in 24 (14.8%, 14 definite, 10 presumed). Of these 13 were alive and on ART, while 11 died. HIV status was not ascertained for the infants lost to follow-up and 23 infants who died.

CONCLUSIONS

HIV infection is being under-diagnosed during pregnancy. Exposed infants have a high mortality and high prevalence of malnutrition. There is an urgent need for standardizing care of exposed infants to promote follow-up and prevent mortality by offering feeding counseling and ensuring early infection detection.

Neurodevelopmental impairment among infants born to mothers infected with human immunodeficiency virus and uninfected mothers from three peri-urban primary care clinics in Harare, Zimbabwe

AIM

The aim of this article is to document the risk of neurodevelopmental impairment (NDI) among infants enrolled in a programme for the prevention of mother-to-child transmission of HIV (human immunodeficiency virus) in Zimbabwe using the Bayley Infant Neurodevelopmental Screener (BINS).

METHOD

We prospectively followed up infants at three primary care clinics in Harare, Zimbabwe. Neurodevelopmental assessments using the BINS were conducted during the first 12 months of life. NDI risk category and associated risk factors were examined.

RESULTS

Of the 598 infants assessed, 305 (51%) were female and 293 (49%) were male. Sixty-five infants (11%) were infected with HIV, 188 (31%) were exposed but uninfected, 287 (48%) were unexposed, and 58 (10%) were of unknown status. The prevalence of a high risk of NDI was 9.4% (95% confidence interval [CI] 7.1-11.1%): 9.2% in males and 9.6% in females. Of the 598 infants, 549 (92%) had ever been breastfed, 49% of whom had mothers infected with HIV. The risk of NDI was higher among infants infected early with HIV, i.e. by 3 months of age (p value <0.001). The NDI high-risk category included twice as many infants infected with HIV as uninfected infants (odds ratio [OR] 2.1; 95% CI 1.0-4.3). After adjusting for other factors, head circumference and family financial subsistence remained risk factors for NDI with an OR of 2.22 (1.04-4.82) and 2.55 (1.02-6.36) respectively.

INTERPRETATION

The background prevalence of high-risk NDI category of 9.4% across groups seems high but is similar to that reported previously in developing countries. Integration of an early infant neurodevelopmental screening programme into child HIV management protocols will assist in the early referral of children exposed to HIV.

Neurologic and neurobehavioral sequelae in children with human immunodeficiency virus (HIV-1) infection

The range and extent of neurologic and neurobehavioral complications of human immunodeficiency virus (HIV-1) infection in children are under-described. Seventy-eight children with HIV-1 infection (32 females) were assessed for neurologic complications. Forty-six children had abnormal neurology examinations. Thirty-three children had global pyramidal tract signs, 5 had a hemiparesis, 4 had peripheral neuropathy, 18 had visual impairment, and 5 had hearing impairment. Thirty-nine of 63 children over 1 year of age had neurobehavioral problems. Of 24 children with HIV encephalopathy, 74% had severe immunosuppression and 45% were not receiving antiretroviral therapy. Twelve children had prior opportunistic central nervous system infections, and 9 had epilepsy. Diverse neurologic and neurobehavioral deficits are common in children with HIV-1 infection. Children with severe immunosuppression, who were not receiving antiretroviral therapy, were growth impaired and less than 1 year of age, were at greatest risk for developing neurologic complications.

Cognitive and psychosocial development of HIV pediatric patients receiving highly active anti-retroviral therapy: a case-control study

BACKGROUND

The psychosocial development of pediatric HIV patients has not been extensively evaluated. The study objectives were to evaluate whether emotional and social functions are differentially associated with HIV-related complications.

METHODS

A matched case-control study design was conducted. The case group (n = 20) consisted of vertically infected children with HIV (aged 3-18 years) receiving HAART in Greece. Each case was matched with two randomly selected healthy controls from a school-based population. CNS imaging and clinical findings were used to identify patients with HIV-related neuroimaging abnormalities. The Wechsler Intelligence Scale III and Griffiths Mental Abilities Scales were applied to assess cognitive abilities. The age specific Strengths and Difficulties Questionnaire was used to evaluate emotional adjustment and social skills. The Fisher's exact test, student's t-test, and Wilcoxon rank sum test were used to compare categorical, continuous, and ordinal scores, respectively, of the above scales between groups.

RESULTS

HIV patients without neuroimaging abnormalities did not differ from patients with neuroimaging abnormalities with respect to either age at HAART initiation (p = 0.306) or months of HAART treatment (p = 0.964). While HIV patients without neuroimaging abnormalities had similar cognitive development with their healthy peers, patients with neuroimaging abnormalities had lower mean General (p = 0.027) and Practical (p = 0.042) Intelligence Quotient scores. HIV patients without neuroimaging abnormalities had an increased likelihood of both Abnormal Emotional Symptoms (p = 0.047) and Hyperactivity scores (p = 0.0009). In contrast, HIV patients with neuroimaging abnormalities had an increased likelihood of presenting with Abnormal Peer Problems (p = 0.033).

CONCLUSIONS

HIV patients without neuroimaging abnormalities are more likely to experience maladjustment with respect to their emotional and activity spheres, while HIV patients with neuroimaging abnormalities are more likely to present with compromised social skills. Due to the limited sample size and age distribution of the study population, further studies should investigate the psychosocial development of pediatric HIV patients following the disclosure of their condition.

Long-term outcome of surgically managed necrotizing enterocolitis in a developing country

Necrotizing enterocolitis (NEC) is a serious condition with a high morbidity and mortality commonly affecting premature babies. Data for the impact of the long-term disease burden in developing countries are limited although poor long-term outcome of surgically managed patients has been shown in terms of increased risk of neurodevelopmental delay, increased infectious disease burden and abnormal neurological outcomes in the developed world.

PURPOSE

To evaluate the long-term outcome of a pre-human immunodeficiency virus pandemic NEC cohort to characterize common risk factors and outcome in a developing world setting.

METHODS

A retrospective review of medical records was carried out on a cohort of 128 premature neonates with surgical NEC (1992-1995). Morbidity, mortality and long-term outcome were evaluated.

RESULTS

Data for 119 of 128 sequentially managed neonates with surgically treated NEC was available. Mean gestational age was 32 weeks and average birth weight was 1,413 g. Early (30-day postoperative) survival was 69% (n = 82) overall and 71% in the <1,500 g birth weight group (n = 68; 53%). Overwhelming sepsis (n = 16) or pan-intestinal necrosis (n = 18) accounted for most of the early deaths. Late deaths (>30 days postoperatively, n = 22) resulted from short bowel syndrome (5), sepsis (9), intraventricular hemorrhage (1) and undetermined causes (7). On follow-up (mean follow-up 39 months, 30 for >2 years), long-term mortality increased to 50%. Late surgical complications included late colonic strictures (9), incisional hernias (2) and adhesive bowel obstruction (3). Fifteen patients had short bowel syndrome, of which 10 (66%) survived. Of the long-term survivors, 8 (20%) had severe neurological deficits and 20 (49%) had significant neurodevelopmental delay. Neurological deficits included severe auditory impairment [5 (12%)] and visual impairment [4 (10%)]. Recurrent infections and gastrointestinal tract complaints requiring hospital admission occurred in 16 (39%) of survivors.

CONCLUSION

Necrotizing enterocolitis in premature infants impacts morbidity and mortality considerably. A number do well in a developing country, but septic complications may be ongoing and recurrent. The high risk of neurodevelopmental and other problems continue beyond the neonatal period and patients should be "flagged" on for careful follow-up.

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.

Patterns of postnatal growth in HIV-infected and HIV-exposed children

HIV infection can contribute to disturbances in both linear growth and weight gain in early childhood, with disturbances often apparent as early as 3 months of age. There is little evidence for a difference in the early growth of HIV-exposed but uninfected children compared to healthy controls. Owing to the close association of growth with immune function and clinical progression, an understanding of growth patterns may be an important tool to ensure the provision of appropriate care to HIV-infected and exposed children. Timely growth monitoring may be used to improve the clinical course and quality of life of these children.

The impact of environmental risk factors on HIV-associated cognitive decline in children

Both the human immunodeficiency virus (HIV) and environmental stress have been independently associated with decreased cognitive functioning in children. Given that they are also known to have a strong relationship with each other, the present study sought to test the hypothesis that children in conditions of high environmental risk would be at greater risk for the cognitive complications related to immunosuppression. A retrospective review was conducted to examine the records of 141 children treated at a large pediatric AIDS clinic from 1993 to 2000. CD4+ lymphocyte levels were recorded from laboratory results and IQ scores were recorded from routine psychological evaluations. Key indicators of environmental risk were collected and combined into one measure of overall environmental risk. Pearson product moment correlations were conducted to examine the relationship between environmental risk, age-adjusted CD4 and IQ. Results indicated a significant correlation between CD4 and IQ, with higher levels of immunocompetence predicting higher IQ scores. When subjects were dichotomized based on their environmental risk score, there was no relationship between CD4 count and IQ in the low environmental risk group. In contrast, CD4 was positively associated with IQ in the high environmental risk group. It is proposed that this may be due to gp120 levels in immunocompromised children being particularly toxic to the hippocampus and cortex under conditions of high stress but not so under conditions of low stress.

Neurocognitive function profile in HIV-infected school-age children

OBJECTIVES

Evaluation of neurocognitive function of school-age children with HIV.

DESIGN

Cross-sectional observational study.

METHODS

Twenty-two children (median age 9.46 years) with perinatally acquired HIV infection were administered a global intelligence test and tests from the Amsterdam Neuropsychological Tasks (ANT) program. The relationship between various patient-, disease- and treatment factors and neurocognitive outcome variables was examined.

RESULTS

Compared with age-appropriate norms, mean IQ of the HIV-infected children was in the average range. However, the HIV-infected children performed poorer on several neuropsychological tests compared with age-appropriate norms. Executive function (attentional flexibility, visuospatial working memory) and processing speed emerged as the most sensitive cognitive measures in relation to HIV disease. The correlational analyses resulted in only two significant outcomes, showing that higher CD4% at initiation of highly active antiretroviral therapy (HAART) and longer treatment duration were associated with better working memory function and attentional control, respectively.

CONCLUSIONS

These exploratory data suggest that subtle neurocognitive impairments may exist in HIV-infected school-age children, in particular characterized by compromised executive function and slowed information processing. Further research with larger sample sizes is needed to confirm these findings.

Twenty years of psychoneuroimmunology and viral infections in Brain, Behavior, and Immunity

For 20 years, Brain, Behavior, and Immunity has provided an important venue for the publication of studies in psychoneuroimmunology. During this time period, psychoneuroimmunology has matured into an important multidisciplinary science that has contributed significantly to our knowledge of mind, brain, and body interactions. This review will not only focus on the primary research papers dealing with psychoneuroimmunology, viral infections, and anti-viral vaccine responses in humans and animal models that have appeared on the pages of Brain, Behavior, and Immunity during the past 20 years, but will also outline a variety of strategies that could be used for expanding our understanding of the neuroimmune-viral pathogen relationship.

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.

Interaction between Plasmodium falciparum and human immunodeficiency virus type 1 on the central nervous system of African children

Plasmodium falciparum and human immunodeficiency virus type 1 (HIV-1) infections are common in children living in sub-Saharan Africa (SSA). Both of these pathogens affect the central nervous system (CNS). Most HIV-1 infection of children in this region is acquired from infected mothers, particularly during breast-feeding and at the time of delivery. Over a third of children infected by birth will have died before their first birthday, before overt CNS manifestations have developed. The most common manifestations of primary CNS infection include neurodevelopmental delay, impaired brain growth, motor deficits, and behavioral problems. These deficits may also result from infections, neoplasm, or stroke. Cognitive impairments become more evident if the child survives for longer, but in Africa, children rarely survive past their fifth birthday. In malaria endemic areas, severe falciparum malaria usually develops after 6 months of age, and most of the CNS manifestations are more common in children over 1 year old. About 11% of children develop neurological deficits following cerebral malaria, most of which improve within 2 years of the insult. However, up to 24% of children may have neurocognitive impairments following severe malaria. The effect of milder malaria and coincidental parasitization on cognitive function is unknown. Other comorbidities that are common in SSA, such as malnutrition or micronutrient deficiencies, may influence children's neurodevelopment. The coinfection of malaria and HIV-1 may aggravate the neurodevelopmental impairments documented in these children. However, to date there are little published data, although it may have a profound effect of children living in SSA.

Health, neurologic, and cognitive status of HIV-infected, long-surviving, and antiretroviral-naive Ugandan children

OBJECTIVE

The purpose of this study was to assess the health status and school-age neurodevelopmental progress of antiretroviral treatment (ARVT)-naive, HIV-infected Ugandan children who had been followed as part of cohorts of children born to HIV-infected and -noninfected mothers between 1989 and 1993.

METHODS

Twenty-eight children, aged 6 to 12 years, vertically infected with HIV-1 and never treated with ARVT were evaluated in terms of health status, neurologic, and psychometric testing. A randomly selected group of 42 seroreverters and 37 HIV-1 negative children who were age- and gender-matched and who had been followed in the same cohorts were evaluated also. The families studied were homogenous in their socioeconomic status. None of the mothers or children had received ARVT or been exposed to illicit drugs.

RESULTS

The HIV-infected children showed significantly more evidence of acute malnutrition. They also had more illness, especially parotitis, otitis media, upper respiratory infections, and lymphadenopathy. However, they did not differ significantly in neurologic and cognitive assessments when compared with age- and gender-matched seroreverter and HIV-negative children. They were in the normal range with respect to neurologic and psychometric development measures.

CONCLUSIONS

These children seem to represent a significant subgroup of HIV-infected child survivors for whom the progress of the disease is less aggressive throughout early life. Given the fact that many infants, especially in developing countries, continue to be born without the benefit of perinatal ARVT, there will likely continue to be many older HIV-infected children in the same situation as those described in this follow-up study. They will not have been recognized as being HIV-infected. It is important that such children be identified and offered access to ARVT and other appropriate support services.

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).

HIV exposure: neonatal considerations

The presence of human immunodeficiency virus (HIV) in pregnant women puts infants at risk for exposure through placental infection and contact with contaminated maternal blood and genital secretions. Efforts to combat this inevitably fatal disease continue to focus on preventing transmission of the virus from a mother who has HIV to her newborn during the prenatal, intrapartum, and postnatal periods. Prophylaxis against transmission and vigilant assessment for indicators of infection are hallmarks of appropriate health care for infants exposed to HIV.

Neuropsychological consequences of HIV in children

Pediatric HIV has reached epidemic proportions. In 1997, 1.1 million children younger than 15 were living with HIV or AIDS. The virus affects children cognitively and developmentally due to the immaturity of their nervous systems and immune systems. Studies in the area of neuropsychological deficits are as yet limited in number and less well developed than studies on adult HIV. However, despite methodological weaknesses, the literature has proven conclusively that pediatric HIV affects children cognitively, developmentally, emotionally, psychologically, behaviorally, and educationally. Although treatments are allowing these children to live longer, the effects of the virus remain, requiring special care. This review examines the mechanisms behind HIV in children, the neuropsychological findings to date, and the limitations of this work. Possible useful future approaches in understanding the neuropsychological course of the disorder, as well as directions for treatment and prevention are addressed.

Treatment with highly active antiretroviral therapy in human immunodeficiency virus type 1-infected children is associated with a sustained effect on growth

INTRODUCTION

Growth failure is a common feature of children with human immunodeficiency virus type 1 (HIV-1) infection. Children who are treated with mono or dual nucleoside analogue reverse transcriptase inhibitor (NRTI) therapy show a temporary increase in weight gain and linear growth rate. In adults, protease-inhibitor-containing antiretroviral therapy is associated with a sustained weight gain and increased body mass index (BMI). Experience with protease inhibitors and growth in children is still limited. The data mainly deal with short-term effects on growth.

OBJECTIVE

To evaluate the effect of highly active antiretroviral therapy (HAART) on growth in children with HIV-1 infection.

DESIGN AND METHODS

We analyzed selected growth parameters, clinical data, and laboratory results as part of a prospective, open, uncontrolled, multicenter study to evaluate the clinical, immunologic, and virologic response to HAART consisting of indinavir, zidovudine, and lamivudine in children with HIV-1 infection. Height and weight were measured at 0, 12, 24, 36, 48, 60, 72, 84, and 96 weeks after initiation of HAART. Information about the children's growth before enrollment in the study was retrieved from the hospital medical records and/or the school doctor or health center. BMI was calculated. z Scores were used to express the standard deviation (SD) in SD units from the Dutch reference curves for age and gender. Viral loads and CD4+ T-cell counts were examined prospectively and related to these growth parameters. z Scores were also calculated for CD4+ T-cell counts to correct for age-related differences. A z score of 0 represents the P50, which is exactly the age/sex-appropriate median. A height z score of -1 indicates that a child's height is 1 SD below the age- and gender-specific median height for the normal population. Virologic responders were defined as those who either reached an undetectable viral load (<500 copies/mL) or had a >1.5 log reduction in viral load compared with baseline at week 12 after the initiation of HAART, which was maintained during the follow-up period. RESULTS.

PATIENTS

Twenty-four patients were included (age: 0.4-16.3 years at baseline), with a median HIV-1 RNA load of 105 925 copies/mL (5.03 log), a median CD4+ T-cell count of 0.586 x 10(9)/L (median z score: -2.28 SD), a median height z score of -1.22, a median weight z score of -0.74, and a median baseline BMI z score of -0.32. Eleven patients were naive to antiretroviral therapy, and 13 patients had received previous treatment with NRTI monotherapy. Twenty children used indinavir and 4 children used nelfinavir as part of HAART. VIROLOGIC AND IMMUNOLOGIC RESPONSES TO HAART: Seventeen children were virologic responders, and 7 children were virologic nonresponders. In patients naive to NRTIs, median baseline viral loads were significantly higher than in pretreated patients. However, at weeks 48 and 96, there was no significant difference between the viral loads of both groups. At baseline, there was no significant difference in CD4+a T-cell z scores between virologic responders and nonresponders or between naive and pretreated patients. During 96 weeks of HAART, the increase of CD4+ T-cell z score was significantly higher in responders than in nonresponders. The increase in CD4+ T-cell z score was not significantly different for naive and pretreated patients. HEIGHT, WEIGHT, AND BMI z SCORE CHANGES: We found that there was a trend toward a significantly increased z score change during 96 weeks of HAART compared with the z score change before HAART initiation for height and weight, but not for BMI. GROWTH AND VIROLOGIC RESPONSE TO HAART: When the data were analyzed separately for virologic responders and nonresponders, virologic responders showed significant increases in height and weight. The height and weight of virologic nonresponders did not change significantly. The BMI did not change significantly in responders or in nonresponders. GROWTH AND IMMUNOLOGIC RESPONSE TO HAART: The increase of weight and BMI z scores from baseline correlated positively with the CD4+ T-cell z score increase from baseline. It did not correlate with absolute CD4+ T-cell count increase. Height z score increase did not correlate with CD4+ T-cell z score or with absolute CD4+ T-cell counts. GROWTH AND PREVIOUS NRTI TREATMENT: The height z score decrease from week -48 to baseline was significantly larger in naive than in pretreated patients. The weight and BMI z score change from week -48 to baseline was not significantly different for pretreated and naive patients. From baseline to week 96, the height and weight z score change increased significantly in naive patients but not in pretreated patients compared with the change from week -48 to baseline. The BMI z score did not change significantly over 96 weeks of HAART for naive or pretreated patients. GROWTH AND CLINICAL STAGE OF INFECTION: The clinical stage of infection according to the Centers for Disease Control and Prevention classification correlated negatively with the BMI z score and the weight z score at baseline but not with the height z score. Thus, children with the most severe clinical disease had the lowest BMI and weight z scores at baseline. The BMI z score increased more in children with more advanced clinical infection at baseline, who had lower BMI at baseline. The clinical stage of infection did not correlate with the change in weight z score from baseline to week 96.

CONCLUSIONS

HAART has a positive influence effect on the growth of HIV-1-infected children. This effect is sustained for at least 96 weeks. Height and weight are favorably influenced in children in whom HAART leads to a reduction of the viral load of at least 1.5 log or to <500 copies/mL and to an increase in the CD4+ T-cell z score. In contrast to the increase of the BMI in adults on HAART, BMI did not increase in all children effectively treated with HAART. BMI increased more in children with an advanced stage of infection and a poor nutritional status at baseline. Data from pretreated and naive patients were difficult to interpret, because the baseline characteristics of these 2 groups differed too much.

Neurological and developmental effects of HIV and AIDS in children and adolescents

HIV-related encephalopathy is an important problem in vertically infected children with HIV. Infected infants may manifest early, catastrophic encephalopathy, with loss of brain growth, motor abnormalities, and cognitive dysfunction. Even without evidence of AIDS, infected infants score lower than serorevertors on developmental measures, particularly language acquisition. Children with perinatal or later transfusion-related infection generally are roughly comparable developmentally to their peers until late in their course. Symptoms similar to adult AIDS dementia complex are occasionally seen in adolescents with advanced AIDS, including dementia, bradykinesia, and spasticity. Opportunistic CNS infections such as toxoplasmosis and progressive multifocal leukoencephalopathy are less common in children and adolescents than in adults. Increasing evidence suggests that aggressive antiretroviral treatment may halt or even reverse encephalopathy. Neuroimaging changes may precede or follow clinical manifestations, and include early lenticulostriate vessel echogenicity on cranial ultrasound, calcifying microangiopathy on CT scan, and/or white matter lesions and central atrophy on MRI. Differential diagnosis of neurological dysfunction in an HIV-infected infant includes the effects of maternal substance abuse, other CNS congenital infections, and other causes of early static encephalopathy. Initial entry of HIV into the nervous system occurs very early in infection. The risk of clinical HIV encephalopathy increases with very early age of infection and with high viral loads. Virus is found in microglia and brain derived macrophages, not neurons. The neuronal effect of HIV is probably indirect, with various cytokines implicated. Apoptosis is the presumed mechanism of damage to neurons by HIV.

An infection-based model of neurodevelopmental damage

Perinatal exposure to infectious agents and toxins is linked to the pathogenesis of neuropsychiatric disorders, but the mechanisms by which environmental triggers interact with developing immune and neural elements to create neurodevelopmental disturbances are poorly understood. We describe a model for investigating disorders of central nervous system development based on neonatal rat infection with Borna disease virus, a neurotropic noncytolytic RNA virus. Infection results in abnormal righting reflexes, hyperactivity, inhibition of open-field exploration, and stereotypic behaviors. Architecture is markedly disrupted in hippocampus and cerebellum, with reduction in granule and Purkinje cell numbers. Neurons are lost predominantly by apoptosis, as supported by increased mRNA levels for pro-apoptotic products (Fas, caspase-1), decreased mRNA levels for the anti-apoptotic bcl-x, and in situ labeling of fragmented DNA. Although inflammatory infiltrates are observed transiently in frontal cortex, glial activation (microgliosis > astrocytosis) is prominent throughout the brain and persists for several weeks in concert with increased levels of proinflammatory cytokine mRNAs (interleukins 1alpha, 1beta, and 6 and tumor necrosis factor alpha) and progressive hippocampal and cerebellar damage. The resemblance of these functional and neuropathologic abnormalities to human neurodevelopmental disorders suggests the utility of this model for defining cellular, biochemical, histologic, and functional outcomes of interactions of environmental influences with the developing central nervous system.

HIV neuropathogenesis and therapeutic strategies

Human immunodeficiency virus (HIV)-1 neuropathogenesis can be divided into three important components: (i) virus entry into the nervous system; (ii) the role of viral proteins and/or cellular products in neural tissue damage; (iii) the mechanisms of neuronal injury/death. Both blood derived macrophages or trafficking HIV-1 infected T-lymphocytes have been implicated in viral entry to the central nervous system (CNS). The major cell type harboring productive HIV-1 infection in the nervous system is the perivascular macrophage/microglia. The HIV-1 infection of brain astrocytes, restricted to the expression of regulatory gene products, may cause astrocyte dysfunction and contribute to neuronal injury or to disruption of the blood-brain barrier (BBB). Studies of cerebrospinal fluid and postmortem tissues reveal chronic inflammation/immune activation in the nervous system during the later stages of HIV-1 infection associated with disruption of BBB integrity. Blood-brain barrier damage may underlie the white matter pallor described in HIV-1 infection and could result in further entry into the CNS of toxic viral or cellular products, or additional HIV-1 infected cells. The HIV infected and activated macrophages/microglia produce excessive amounts of pro-inflammatory cytokines, including tumor necrosis factor alpha, and platelet activating factor. These products are directly toxic to human neurons in vitro. The HIV-1 envelope glycoprotein, gp 120 may stimulate the release of toxic factors from brain macrophages. Blocking N-methyl-D-aspartate (NMDA; or AMPA) glutamate receptors can antagonize candidate toxins of both viral and cellular origin. It has been postulated that (weak) excitotoxicity leads to oxidative stress in neurons and ultimately to apoptosis. Neuronal apoptosis occurs in the brains of both children and adults with HIV-1 infection. This understanding of HIV neuropathogenesis implies that therapeutic strategies should include: (i) anti-retroviral medications to decrease systemic and CNS virus load, and possibly to prevent perinatal transmission of HIV; (ii) anti-inflammatory compounds to decrease the chronic immune activation in microglia and allow the restoration of BBB integrity; and (iii) neuroprotective compounds to reduce neuronal injury and apoptotic death.