Acylcarnitine Profiles in HIV-Exposed, Uninfected Neonates in the United States

Lower Insulin Sensitivity Through 36 Months of Life With in Utero HIV and Antiretroviral Exposure in Botswana: Results From the Tshilo Dikotla Study

BACKGROUND

There are little data on changes in insulin sensitivity during the first few years of life following in utero human immunodeficiency virus (HIV) and antiretroviral (ARV) exposure.

METHODS

The Tshilo Dikotla study enrolled pregnant persons with HIV (PWH) (receiving tenofovir/emtricitabine or lamivudine plus dolutegravir or efavirenz) and pregnant individuals without HIV, as well as their liveborn children. Newborns were randomized to receive either zidovudine (AZT) or nevirapine (NVP) postnatal prophylaxis. Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) was assessed at birth and 1, 18, 24, and 36 months of life. We fit linear mixed-effects models to evaluate the association between in utero HIV/ARV exposure and average HOMA-IR from birth through 36 months of life, adjusting for confounders.

RESULTS

A total of 419 children were included (287 with in utero HIV/ARV exposure and uninfected [CHEU] and 132 without in utero HIV/ARV exposure [CHUU]). CHEU were born to older women (29.6 vs 25.3 years of age) with higher gravidity (3 vs 1). HOMA-IR was persistently higher in CHEU versus CHUU in adjusted analyses (mean difference of 0.07 in log10 HOMA-IR, P  = .02) from birth through 36 months of life. Among CHEU, no differences in HOMA-IR were observed from birth through 36 months by in utero ARV exposure status or between AZT and NVP infant prophylaxis arms.

CONCLUSIONS

In utero HIV/ARV exposure was associated with lower insulin sensitivity throughout the first 36 months of life, indicating persistent early life metabolic disturbances which may raise concern for poorer metabolic health later in life.

Human immunodeficiency virus and antiretroviral therapy-mediated immune cell metabolic dysregulation in children born to HIV-infected women: potential clinical implications

Commencing lifelong antiretroviral therapy (ART) immediately following HIV diagnosis (Option B+) has dramatically improved the health of HIV-infected women and their children, with the majority being of HIV-exposed children born uninfected (HEU). This success has led to an increasing population of HIV-infected women receiving ART during pregnancy and children exposed to ART in utero. Nonetheless, a small proportion of children are still infected with HIV (HEI) each year. HEI children suffer from reduced immunocompetence and host-defence, due to CD4+ T lymphocyte depletion, but also dysregulation of other immune cells including CD8+ T lymphocytes, natural killer (NK) cells, macrophages including B lymphocytes. Furthermore, although HEU children are uninfected, altered immune responses are observed and associated with increased vulnerability to infections. The mechanisms underlying immune dysregulation in HEU children remain poorly described. Building on early studies, emerging data suggests that HIV/ART exposure early in life affects cell metabolic function of HEU children. Prenatal HIV/ART exposure has been associated with dysregulation of mitochondria, including impaired DNA polymerase activity. Furthermore, dysregulation of oxidative phosphorylation (OXPHOS) causes a decreased generation of adenosine triphosphate (ATP) and increased production of reactive oxygen species (ROS), resulting in oxidative stress. These altered metabolic processes can affect immune cell viability and immune responses. Recent studies have indicated that immune-metabolic dysregulation may contribute to HIV-associated pathogenesis and clinical observations associated with HIV and ART exposure in HEU/HEI children. Given the critical role metabolic processes in immune cell functioning, immune-metabolic dysregulation in HEU and HEI children may have implications in effective host-defence responses against pathogens, as well as efficacy of standard ART regimens and future novel HIV cure approaches in HEI children. At the same time, targeting metabolic pathways of immune cells may provide safer and novel approaches for HIV cure strategies. Here, we review the current literature investigating immune-metabolic dysregulation in paediatric HIV pathogenesis.

Immune and Metabolic Alterations in Children with Perinatal HIV Exposure

With the global rollout of mother-to-child prevention programs for women living with HIV, vertical transmission has been all but eliminated in many countries. However, the number of children who are exposed in utero to HIV and antiretroviral therapy (ART) is ever-increasing. These children who are HIV-exposed-but-uninfected (CHEU) are now well recognized as having persistent health disparities compared to children who are HIV-unexposed-and-uninfected (CHUU). Differences reported between these two groups include immune dysfunction and higher levels of inflammation, cognitive and metabolic abnormalities, as well as increased morbidity and mortality in CHEU. The reasons for these disparities remain largely unknown. The present review focuses on a proposed link between immunometabolic aberrations and clinical pathologies observed in the rapidly expanding CHEU population. By drawing attention, firstly, to the significance of the immune and metabolic alterations observed in these children, and secondly, the impact of their healthcare requirements, particularly in low- and middle-income countries, this review aims to sensitize healthcare workers and policymakers about the long-term risks of in utero exposure to HIV and ART.

In-utero HIV exposure and cardiometabolic health among children 5-8 years: findings from a prospective birth cohort in South Africa

OBJECTIVE

To evaluate if in-utero HIV exposure is associated with adverse cardiometabolic health outcomes at 5-8 years of age.

DESIGN

Prospective cohort study.

METHODS

We enrolled a random sample of HIV-exposed but uninfected (HEU) and HIV-unexposed children from the Drakenstein Child Health study, a longitudinal birth cohort study in Cape Town, South Africa, in a cardiometabolic health pilot study. Outcomes were assessed by trained study staff and included: anthropometry, body composition and size, blood pressure, fasting plasma glucose, HbA1c, lipids, and insulin resistance using HOMA-IR. We used multivariable linear and log-binomial regression to estimate associations between HIV-exposure and cardiometabolic outcomes, adjusted for child age, sex, height, body size, and maternal factors as appropriate.

RESULTS

We included 260 children (HEU n = 100, HIV-unexposed n = 160). HEU children had older mothers (median age 30 vs. 26 years), with minimal differences in gestational age and size at birth by HIV-exposure status. In multivariable analyses, HEU children had lower weight-for-age (mean difference -0.35, 95% confidence interval -0.66, -0.05), and height-for-age (mean difference -0.29, 95% confidence interval -0.56, -0.03; z-scores). There were no differences in adiposity, impaired glucose metabolism, or lipid levels by HIV-exposure status. Overall, 12% of children had blood pressure more than 90th percentile, with no differences by HIV-exposure status.

CONCLUSION

Overall, there were few differences in cardiometabolic outcomes between HEU and HIV-unexposed children in this South African cohort. Although these findings are reassuring, monitoring of cardiometabolic health is important as HEU and HIV-unexposed children enter adolescence and cardiometabolic risk trajectories become established.

Lower Insulin Sensitivity in Newborns With In Utero HIV and Antiretroviral Exposure Who Are Uninfected in Botswana

BACKGROUND

Few data exist on early-life metabolic perturbations in newborns with perinatal HIV and antiretroviral (ARV) exposure but uninfected (HEU) compared to those perinatally HIV unexposed and uninfected (HUU).

METHODS

We enrolled pregnant persons with HIV (PWH) receiving tenofovir (TDF)/emtricitabine or lamivudine (XTC) plus dolutegravir (DTG) or efavirenz (EFV), and pregnant individuals without HIV, as well as their liveborn infants. Newborns were randomized to receive either zidovudine (AZT) or nevirapine (NVP) postnatal prophylaxis. Preprandial homeostasis model assessment for insulin resistance (HOMA-IR) was assessed at birth and 1 month. Linear mixed models were fit to assess the association between in utero HIV/ARV exposure and average HOMA-IR from birth to 1 month, adjusting for confounders.

RESULTS

Of 450 newborns, 306 were HEU. HOMA-IR was higher in newborns HEU versus HUU after adjusting for confounders (mean difference of 0.068 in log HOMA-IR, P = .037). Among newborns HEU, HOMA-IR was not significantly different between TDF/XTC/DTG versus TDF/XTC/EFV in utero ARV exposure and between AZT versus NVP newborn postnatal prophylaxis arms.

CONCLUSIONS

Newborns HEU versus HUU had lower insulin sensitivity at birth and at 1 month of life, raising potential concern for obesity and other metabolic perturbations later in life for newborns HEU.

CLINICAL TRIALS REGISTRATION

NCT03088410.

Acylcarnitines and Genetic Variation in Fat Oxidation Genes in HIV-infected, Antiretroviral-treated Children With and Without Myopathy

BACKGROUND

Mitochondrial toxicity resulting in myopathy and lactic acidosis has been described in antiretroviral (ARV)-exposed patients. We hypothesized that myopathy in HIV-infected, ARV-treated children would be associated with metabolic (acylcarnitines) and genetic (variants in metabolic genes) markers of dysfunctional fatty acid oxidation (FAO).

METHODS

Acylcarnitine profiles (ACP) were analyzed for 74 HIV-infected children on nucleoside reverse transcriptase inhibitor (NRTI)-containing ARV. Thirty-seven participants with ≥2 creatine kinase measurements >500 IU (n = 18) or evidence of echocardiographic cardiomyopathy (n = 19) were matched with 37 participants without myopathy. Single nucleotide polymorphisms (SNPs) in FAO genes were also evaluated.

RESULTS

Abnormal ACP was 73% (95% CI: 56%-86%) and 62% (95% CI: 45%-78%) in the myopathic and nonmyopathic groups, respectively. No significant association was found between myopathy and having an abnormal ACP (OR = 2.10, P = 0.22). In univariate analysis, a 1-year increase in NRTI use was associated with a 20% increase in odds of at least 1 ACP abnormality [OR (95% CI) = 1.20 (1.03-1.41); P = 0.02), and a 1-year increase in protease inhibitor use was associated with 28% increase in the odds of having at least 1 ACP abnormality [OR (95% CI) = 1.28 (1.07-1.52); P = 0.006). Three SNPs, all in the gene for the carnitine transporter ( SLC22A5 ), were associated with the cardiomyopathy phenotype.

CONCLUSION

FAO appears to be altered in HIV-infected children with and without myopathy, but abnormal FAO does not fully explain myopathy in ARV-exposed children. Further study of SLC22A5 variation in ARV-exposed people is warranted carnitine transporter dysfunction-related cardiomyopathy may be treatable.

Association of serum PUFA and linear growth over 12 months among 6-10 years old Ugandan children with or without HIV

OBJECTIVE

To quantify PUFA-associated improvement in linear growth among children aged 6-10 years.

DESIGN

Serum fatty acids (FA), including essential FA (EFA) (linoleic acid (LA) and α-linolenic acid (ALA)) were quantified at baseline using GC-MS technology. FA totals by class (n-3, n-6, n-9, PUFA and SFA) and FA ratios were calculated. Height-for-age Z-score (HAZ) relative to WHO population reference values were calculated longitudinally at baseline, 6 and 12 months. Linear regression models estimated PUFA, HIV status and their interaction-associated standardised mean difference (SMD) and 95 % CI in HAZ over 12 months.

SETTING

Community controls and children connected to community health centre in Kampala, Uganda, were enrolled.

PARTICIPANTS

Children perinatally HIV-infected (CPHIV, n 82), or HIV-exposed but uninfected (CHEU, n 76) and community controls (n 78).

RESULTS

Relative to highest FA levels, low SFA (SMD = 0·31, 95 % CI: 0·03, 0·60), low Mead acid (SMD = 0·38, 95 % CI: 0·02, 0·74), low total n-9 (SMD = 0·44, 95 % CI: 0·08, 0·80) and low triene-to-tetraene ratio (SMD = 0·42, 95 % CI: 0·07, 0·77) predicted superior growth over 12 months. Conversely, low LA (SMD = -0·47, 95 % CI: -0·82, -0·12) and low total PUFA (sum of total n-3, total n-6 and Mead acid) (SMD = -0·33 to -0·39, 95 % CI: -0·71, -0·01) predicted growth deficit over 12 months follow-up, regardless of HIV status.

CONCLUSION

Low n-3 FA (ALA, EPA and n-3 index) predicted growth deficits among community controls. EFA sufficiency may improve stature in school-aged children regardless of HIV status. Evaluating efficacy of diets low in total SFA, sufficient in EFA and enriched in n-3 FA for improving child growth is warranted.

Metabolomics in Placental Tissue from Women Living with HIV

It is unknown whether antiretroviral (ARV) drugs in women living with HIV (WLHIV) are associated with mitochondrial toxicity and altered fat oxidation and branched-chain amino acid metabolism in the placenta and fetus. Immediately after delivery, we froze placental biopsies from 20 WLHIV and 20 matched uninfected women. We analyzed global biochemical profiles using high-performance liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry. We used t-tests, principle component analysis, hierarchical clustering, and random forest analysis (RFA) in our analysis. Twelve WLHIV were on protease inhibitors, six on non-nucleoside reverse inhibitors, and two on integrase strand inhibitors with optimized backbone. Mean birth weight of HIV-exposed neonates was significantly lower than unexposed neonates (3,075 g vs. 3,498 g, p = .01) at similar gestational age. RFA identified 30 of 702 analytes that differentiated the placental profiles of WLHIV from uninfected women with 72.5% predictive accuracy. Placental profiles of non-nucleoside reverse transcriptase inhibitor (NNRTI)-treated WLHIV exhibited lower levels of amino acids, including essential and branched-chain amino acids, and some medium-chain acylcarnitines. Placental metabolism may be altered in WLHIV, possibly associated with ARV exposure. The lower birth weight among neonates of WLHIV suggests the need for further studies considering potential deleterious effects of altered placenta metabolism on fetal growth and development.

Placental Vascular Abnormalities in Association With Prenatal and Long-Term Health Characteristics Among HIV-Exposed Uninfected Adolescents and Young Adults

BACKGROUND

HIV-exposed uninfected (HEU) individuals are predisposed to adverse health outcomes, which in part may stem from the influence of an altered intrauterine milieu on fetal programming. The placenta serves as a readout for the effects of the maternal environment on the developing fetus and may itself contribute to the pathogenesis of disease.

SETTING

US academic health system.

METHODS

We leveraged a previously established registry-based cohort of HEU adolescents and young adults to identify 26 subjects for whom placental histopathology was available. We further obtained placental tissue from 29 HIV-unexposed pregnancies for comparison. We examined differences in placental histopathology between the groups and related villous vascularity in the HEU group to prenatal maternal characteristics and long-term health outcomes.

RESULTS

Placentas from HEU pregnancies demonstrated a higher blood vessel count per villus as compared with controls (5.9 ± 1.0 vs. 5.4 ± 0.8; P = 0.05), which was independent of maternal prenatal age, race, body mass index, smoking status, hemoglobin, and gestational age. Furthermore, within the HEU group, lower CD4+ T-cell count during pregnancy was associated with greater placental vascularity (r = -0.44; P = 0.03). No significant relationships were observed between placental blood vessel count per villus and body mass index z-score or reactive airway disease among HEU individuals later in life.

CONCLUSIONS

Placentas from HEU pregnancies demonstrated increased villous vascularity compared with HIV-unexposed controls in proportion to the severity of maternal immune dysfunction. Further studies are needed to examine intrauterine exposure to hypoxia as a potential mechanism of fetal programming in HIV.

Contemporary Issues in Pregnancy (and Offspring) in the Current HIV Era

PURPOSE OF REVIEW

Although antiretroviral therapy (ART) has dramatically reduced mother to child transmission of HIV, data continue to mount that infants exposed to HIV in utero but are not infected (HEU) have serious negative health consequences compared to unexposed infants. This review evaluates recent literature on contemporary issues related to complications seen in pregnant women with HIV and their offspring.

RECENT FINDINGS

Current studies show that HEU infants are at a high risk of adverse outcomes, including premature birth, poor growth, neurodevelopmental impairment, immune dysfunction, infectious morbidity, and death. Etiologies for the observed clinical events and subclinical alterations are complex and multifactorial, and the long-term consequences of many findings are yet unknown. HEU infants have an unacceptable rate of morbidity and mortality from perinatal HIV and ART exposure, even in the modern ART era. Continual monitoring and reporting is imperative to protect this vulnerable population in our everchanging landscape of HIV treatment and prevention.

A Comparison of Metabolic Outcomes Between Obese HIV-Exposed Uninfected Youth From the PHACS SMARTT Study and HIV-Unexposed Youth From the NHANES Study in the United States

BACKGROUND

Metabolic perturbations in HIV-exposed uninfected (HEU) obese youth may differ from those in the general obese pediatric population.

METHODS

Metabolic parameters of obese (body mass index Z-score >95th percentile) HEU youth in the Pediatric HIV/AIDS Cohort Study (PHACS) Surveillance Monitoring of ART Toxicities (SMARTT) study were compared with a matched sample of obese youth from the US National Health and Nutrition Examination Survey (NHANES). We evaluated systolic and diastolic hypertension (blood pressure ≥90th percentile for age, sex, and height), total cholesterol >200 mg/dL, high-density lipoprotein cholesterol <35 mg/dL, low-density lipoprotein cholesterol >130 mg/dL, triglycerides (TGs) >150 mg/dL, and Homeostatic Model Assessment-Insulin Resistance >4.0. Modified Poisson regression models were fit to quantify the prevalence ratio (PR) of each outcome comparing the 2 cohorts, adjusting for confounders.

RESULTS

The blood pressure outcome analytic subgroup included 1096 participants (n = 304 HEU), the total cholesterol and high-density lipoprotein cholesterol subgroup 1301 participants (n = 385 HEU), and the low-density lipoprotein cholesterol, TG, and Homeostatic Model Assessment-Insulin Resistance subgroup 271 (n = 83 HEU). After adjustment, obese HEU youth had a higher prevalence of systolic and diastolic hypertension [PR = 3.34, 95% confidence interval (CI): 2.48 to 4.50; PR = 2.04, 95% CI: 1.18 to 3.52, respectively], but lower prevalence of insulin resistance (PR = 0.67, 95% CI: 0.54 to 0.85) and hypercholesterolemia (PR = 0.67, 95% CI: 0.44 to 1.01) compared with obese NHANES youth.

CONCLUSIONS

In the United States, obese HEU youth seem to have an increased risk of hypertension, but lower risk of insulin resistance and hypercholesterolemia, compared with a general obese pediatric population. Monitoring for cardiovascular morbidity in adulthood may be warranted in HEU children.

Lower Concentrations of Circulating Medium and Long-Chain Acylcarnitines Characterize Insulin Resistance in Persons with HIV

In human immunodeficiency virus (HIV)-negative individuals, a plasma metabolite profile, characterized by higher levels of branched-chain amino acids (BCAA), aromatic amino acids, and C3/C5 acylcarnitines, is associated with insulin resistance and increased risk of diabetes. We sought to characterize the metabolite profile accompanying insulin resistance in HIV-positive persons to assess whether the same or different bioenergetics pathways might be implicated. We performed an observational cohort study of 70 nondiabetic, HIV-positive individuals (50% with body mass index ≥30 kg/m²) on efavirenz, tenofovir, and emtricitabine with suppressed HIV-1 RNA levels (<50 copies/mL) for at least 2 years and a CD4⁺ count over 350 cells/μL. We measured fasting insulin resistance using the homeostatic model assessment 2, plasma free fatty acids (FFA) using gas chromatography, and amino acids, acylcarnitines, and organic acids using liquid chromatography/mass spectrometry. We assessed the relationship of plasma metabolites with insulin resistance using multivariable linear regression. The median age was 45 years, median CD4⁺ count was 701 cells/μL, and median hemoglobin A1c was 5.2%. Insulin resistance was associated with higher plasma C3 acylcarnitines (p = .01), but not BCAA or C5 acylcarnitines. However, insulin resistance was associated with lower plasma levels of C18, C16, C12, and C2 acylcarnitines (p ≤ .03 for all), and lower C18 and C16 acylcarnitine:FFA ratios (p = .002, and p = .03, respectively). In HIV-positive persons, lower levels of plasma acylcarnitines, including the C2 product of complete fatty acid oxidation, are a more prominent feature of insulin resistance than changes in BCAA, suggesting impaired fatty acid uptake and/or mitochondrial oxidation is a central aspect of glucose intolerance in this population.

Health and survival of HIV perinatally exposed but uninfected children born to HIV-infected mothers

PURPOSE OF REVIEW

The number of HIV-exposed but uninfected (HEU) infants exposed to both HIV and multiple antiretroviral drugs in utero and during prolonged breastfeeding is increasing in low-income countries where HIV prevalence is the highest. We review recent evidence on the effects of perinatal/postnatal exposure to maternal HIV and combined antiretroviral therapy (cART) on health outcomes of HEU children (mitochondrial and metabolic toxicity, adverse pregnancy outcomes, neurodevelopment, growth, infectious morbidity, and mortality).

RECENT FINDINGS

Several studies have reported ART-associated mitochondrial toxicity and metabolic disorders with conflicting results on adverse pregnancy outcomes, underscoring the need to conduct further investigations on these questions. Studies about congenital abnormalities report no significant differences between HEU exposed to ART and HIV-unexposed (HUU) children. Updated French data showed no significant difference in cancer incidence between HEU cART-exposed children and the general paediatric population. Furthermore, HEU children exposed to maternal cART have modest but significant impairment of development and a higher risk of growth impairment. Finally, HEU have higher risks of infections (mainly low respiratory tract infections and diarrhoea) and malaria than HUU children, particularly in children not breastfed or after early weaning. Higher mortality risk from infectious disease is reported in HEU compared to HUU children.

SUMMARY

As we move toward the elimination of mother-to-child transmission of HIV, HEU children are an emerging population whose health outcomes remain to be fully described. Future large cohorts of HEU children using careful comparison groups of HUU in the post-ART era are needed to better understand their long-term health outcomes.

Strategies for Monitoring Outcomes in HIV-Exposed Uninfected Children in the United Kingdom

Surveillance of pregnancies in women living with HIV is carried out on a national basis in the United Kingdom (UK) through the National Study of HIV in Pregnancy and Childhood. There are currently around 1100-1200 HIV-exposed uninfected (HEU) infants born every year in the UK, where vertical transmission of HIV now occurs in fewer than 5 in every 1000 pregnancies. By the end of 2014, there was a cumulative total of more than 15,000 HEU children with any combination antiretroviral therapy (cART) exposure and more than 5000 with cART exposure from conception in the UK. HEU infants are increasingly being exposed to newer antiretroviral drugs for which less is known regarding both short- and long-term safety. In this commentary, we describe the approaches that have been taken to explore health outcomes in HEU children born in the UK. This includes the Children exposed to AntiRetroviral Therapy (CHART) Study, which was a consented follow-up study carried out in 2002-2005 of HEU children born in 1996-2004. The CHART Study showed that 4% of HEU children enrolled had a major health or development problem in early childhood; this was within expected UK norms, but the study was limited by small numbers and short-term follow-up. However, the problems with recruitment and retention that were encountered within the CHART Study demonstrated that comprehensive, clinic-based follow-up was not a feasible approach for long-term assessment of HEU children in the UK. We describe an alternative approach developed to monitor some aspects of their long-term health, involving the "flagging" of HEU infants for death and cancer registration with the UK Office for National Statistics. Some of the ethical concerns regarding investigation of long-term outcomes of in utero and perinatal exposure to antiretrovirals, including those relating to consent and confidentiality, are also discussed.