Serious neonatal morbidities are associated with differences in DNA methylation among very preterm infants

Neonatal and maternal morbidity rates in low-risk nulliparous women across different gestational ages

This study examines perinatal outcomes in low-risk nulliparous women and their neonates across different gestational ages. Using data from 18 hospitals, we analyzed maternal and neonatal complications for deliveries at 37-38 weeks, 39-40 weeks, and 41 weeks, focusing on the risks associated with early- and late-term deliveries. Neonatal complications were highest at 37-38 weeks, while maternal complications, primarily anemia, were more prevalent at 41 weeks. These findings suggest that deliveries closer to 39-40 weeks may offer optimal outcomes for maternal and neonatal health. By providing insights into the impact of gestational timing, this study aids clinical decision-making for safe delivery timing, potentially improving perinatal outcomes for low-risk pregnancies.

Increased PLAGL1 Gene Methylation in Cord Blood is Positively Correlated with Brain Injury in Chorioamniotic Preterm Infants

The study aims to explore the epigenetic mechanisms of neurodevelopmental impairment accompanied in chorioamniotic preterm infants. Our study included 16 full-term infants and 69 preterm infants. The methylation status of the pleomorphic adenoma gene-like 1 (PLAGL1) gene in the cord blood was determined by pyrosequencing. Brain B-ultrasonography and magnetic resonance imaging (MRI) were performed to diagnose brain injury. The activity of candidate fragments of PLAGL1 and the effect of methylation on PLAGL1 activity were evaluated by double luciferase reporter assay. The data showed that there were no differences in the methylation levels of each Cytosine-phosphate-Guanine (CpG) site of PLAGL1 between full-term and preterm infants. Within preterm infants, the methylation levels of the CpG2, CpG3, CpG4, and CpG5 sites were increased in the chorioamnionitis group compared with the no chorioamnionitis group. The areas under curves (AUCs) of the receiver operating characteristic (ROC) curves of CpG2, CpG3, CpG4, and CpG5 were 0.656, 0.653, 0.670, and 0.712, respectively. Meanwhile, the methylation level of the CpG2 site was increased in preterm babies with brain injury compared with those without brain injury, and the AUC of CpG2 was 0.648, with a sensitivity of 75.9% and a specificity of 50.0%. A double luciferase reporter assay revealed that PLAGL1 fragments had enhancer-like activity and that the methylated form of PLAGL1 weakened this activity. Thus, PLAGL1 hypermethylation in chorioamniotic preterm infants is positively correlated with brain injury. Our results suggest a potential use for PLAGL1 methylation as a biomarker in the diagnosis of brain injury.

Post-translational modifications and bronchopulmonary dysplasia

Bronchopulmonary dysplasia is a prevalent respiratory disorder posing a significant threat to the quality of life in premature infants. Its pathogenesis is intricate, and therapeutic options are limited. Besides genetic coding, protein post-translational modification plays a pivotal role in regulating cellular function, contributing complexity and diversity to substrate proteins and influencing various cellular processes. Substantial evidence indicates that post-translational modifications of several substrate proteins are intricately related to the molecular mechanisms underlying bronchopulmonary dysplasia. These modifications facilitate the progression of bronchopulmonary dysplasia through a cascade of signal transduction events. This review outlines the relationships between substrate protein phosphorylation, acetylation, ubiquitination, SUMOylation, methylation, glycosylation, glycation, S-glutathionylation, S-nitrosylation and bronchopulmonary dysplasia. The aim is to provide novel insights into bronchopulmonary dysplasia's pathogenesis and potential therapeutic targets for clinical management.

Parental arsenic exposure and tissue-specific DNA methylation in Bangladeshi infants with spina bifida

An emerging hypothesis linking arsenic toxicity involves altered epigenetic mechanisms, such as DNA methylation. In this study, we examined the relationship between parents' arsenic exposure and DNA methylation in tissues obtained from 28 infants with spina bifida from Bangladesh. We analyzed arsenic in parents' toenails using inductively coupled plasma mass spectrometry (ICP-MS). DNA methylation was measured in infants' dural tissue, buccal swabs, and whole blood using the Illumina Infinium MethylationEPIC BeadChip. We performed epigenome-wide association analyses (EWAS) and tested differentially methylated regions (DMRs). In EWAS, DNA methylation at cg24039697 in dural tissue was positively associated (β = 0.59, p = 7.6 × 10-9) with father's toenail arsenic concentrations, adjusting for covariates. We did not identify any CpG sites related to father's arsenic exposure in the other tissues, or any CpG sites related to mother's arsenic exposure. Gene ontology analysis identified many biological pathways of interest, including the Wnt signaling pathways. We identified several DMRs across the tissues related to arsenic exposure that included probes mapping to genes that have previously been identified in studies of neural tube defects. This study emphasizes the potential impact of arsenic exposure in fathers, often understudied in epidemiological studies, on DNA methylation in a unique neurological tissue specific to spina bifida.

Neonatal multimorbidity and the phenotype of premature aging in preterm infants

Multimorbidity is the co-occurrence of multiple chronic health problems, associated with aging, frailty, and poor functioning. Children born preterm experience more multimorbid conditions in early life compared to term-born peers. Though neonatal multimorbidity is linked to poor health-related quality of life, functional outcomes, and peer group participation, gaps in our theoretical understanding and conceptualization remain. Drawing from life course epidemiology and the Developmental Origins of Heath and Disease models, we offer a framework that neonatal multimorbidity reflects maturational vulnerability posed by preterm birth. The impact of such vulnerability on health and development may be further amplified by adverse exposures and interventions within the environment of the neonatal intensive care unit. This can be exacerbated by disadvantaged home or community contexts after discharge. Uncovering the physiologic and social antecedents of multiple morbid conditions in the neonatal period and their biological underpinnings will allow for more accurate risk-prediction, counseling, and care planning for preterm infants and their families. According to this framework, the maturational vulnerability to multimorbidity imparted by preterm birth and its negative effects on health and development are not predetermined or static. Elucidating pathways of early biologic and physical aging will lead to improvements in care and outcomes. IMPACT: Multimorbidity is associated with significant frailty and dysfunction among older adults and is indicative of early physiologic aging. Preterm infants commonly experience multimorbidities in the newborn period, an underrecognized threat to long-term health and development. We offer a novel framework incorporating multimorbidity, early cellular aging, and life course health development to innovate risk-prediction, care-planning, and therapeutics.

Early life epigenetics and childhood outcomes: a scoping review

Epigenetics is the study of changes in gene expression, without a change in the DNA sequence that are potentially heritable. Epigenetic mechanisms such as DNA methylation, histone modifications, and small non-coding RNA (sncRNA) changes have been studied in various childhood disorders. Causal links to maternal health and toxin exposures can introduce epigenetic modifications to the fetal DNA, which can be detected in the cord blood. Cord blood epigenetic modifications provide evidence of in-utero stressors and immediate postnatal changes, which can impact both short and long-term outcomes in children. The mechanisms of these epigenetic changes can be leveraged for prevention, early detection, and intervention, and to discover novel therapeutic modalities in childhood diseases. We report a scoping review of early life epigenetics, the influence of maternal health, maternal toxin, and drug exposures on the fetus, and its impact on perinatal, neonatal, and childhood outcomes. IMPACT STATEMENT: Epigenetic changes such as DNA methylation, histone modification, and non-coding RNA have been implicated in the pathophysiology of various disease processes. The fundamental changes to an offspring's epigenome can begin in utero, impacting the immediate postnatal period, childhood, adolescence, and adulthood. This scoping review summarizes current literature on the impact of early life epigenetics, especially DNA methylation on childhood health outcomes.

Contributions of prenatal risk factors and neonatal epigenetics to cognitive outcome in children born very preterm

Children born less than 30 weeks gestational age (GA) are at high risk for neurodevelopmental delay compared to term peers. Prenatal risk factors and neonatal epigenetics could help identify preterm children at highest risk for poor cognitive outcomes. We aimed to understand the associations among cumulative prenatal risk, neonatal DNA methylation, and child cognitive ability at age 3 years, including whether DNA methylation mediates the association between prenatal risk and cognitive ability. We studied 379 neonates (54% male) born less than 30 weeks GA who had DNA methylation measured at neonatal intensive care unit discharge along with 3-year follow-up data. Cumulative prenatal risk was calculated from 24 risk factors obtained from maternal report and medical record and epigenome-wide neonatal DNA methylation was assayed from buccal swabs. At 3-year follow-up, child cognitive ability was assessed using the Bayley Scales of Infant and Toddler Development (third edition). Cumulative prenatal risk and DNA methylation at two cytosine-phosphate-guanines (CpGs) were uniquely associated with child cognitive ability. Using high-dimensional mediation analysis, we also identified differential methylation of 309 CpGs that mediated the association between cumulative prenatal risk and child cognitive ability. Many of the associated CpGs were located in genes (TNS3, TRAPPC4, MAD1L1, APBB2, DIP2C, TRAPPC9, DRD2) that have previously been associated with prenatal exposures and/or neurodevelopmental phenotypes. Our findings suggest a role for both prenatal risk factors and DNA methylation in explaining outcomes for children born preterm and suggest we should further study DNA methylation as a potential mechanism underlying the association between prenatal risk and child neurodevelopment. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Epigenetic associations with neonatal age in infants born very preterm, particularly among genes involved in neurodevelopment

The time from conception through the first year of life is the most dynamic period in human development. This time period is particularly important for infants born very preterm (< 30 weeks gestation; VPT), as they experience a significant disruption in the normal developmental trajectories and are at heightened risk of experiencing developmental impairments and delays. Variations in the epigenetic landscape during this period may reflect this disruption and shed light on the interrelationships between aging, maturation, and the epigenome. We evaluated how gestational age (GA) and age since conception in neonates [post-menstrual age (PMA)], were related to DNA methylation in buccal cells collected at NICU discharge from VPT infants (n = 538). After adjusting for confounders and applying Bonferroni correction, we identified 2,366 individual CpGs associated with GA and 14,979 individual CpGs associated with PMA, as well as multiple differentially methylated regions. Pathway enrichment analysis identified pathways involved in axonogenesis and regulation of neuron projection development, among many other growth and developmental pathways (FDR q < 0.001). Our findings align with prior work, and also identify numerous novel associations, suggesting that genes important in growth and development, particularly neurodevelopment, are subject to substantial epigenetic changes during early development among children born VPT.

Epigenetic modifications in the development of bronchopulmonary dysplasia: a review

While perinatal medicine advancements have bolstered survival outcomes for premature infants, bronchopulmonary dysplasia (BPD) continues to threaten their long-term health. Gene-environment interactions, mediated by epigenetic modifications such as DNA methylation, histone modification, and non-coding RNA regulation, take center stage in BPD pathogenesis. Recent discoveries link methylation variations across biological pathways with BPD. Also, the potential reversibility of histone modifications fuels new treatment avenues. The review also highlights the promise of utilizing mesenchymal stem cells and their exosomes as BPD therapies, given their ability to modulate non-coding RNA, opening novel research and intervention possibilities. IMPACT: The complexity and universality of epigenetic modifications in the occurrence and development of bronchopulmonary dysplasia were thoroughly discussed. Both molecular and cellular mechanisms contribute to the diverse nature of epigenetic changes, suggesting the need for deeper biochemical techniques to explore these molecular alterations. The utilization of innovative cell-specific drug delivery methods like exosomes and extracellular vesicles holds promise in achieving precise epigenetic regulation.

Epigenetic associations in HPA axis genes related to bronchopulmonary dysplasia and antenatal steroids

BACKGROUND

Bronchopulmonary dysplasia (BPD), a common morbidity among very preterm infants, is associated with chronic disease and neurodevelopmental impairments. A hypothesized mechanism for these outcomes lies in altered glucocorticoid (GC) activity. We hypothesized that BPD and its treatments may result in epigenetic differences in the hypothalamic-pituitary-adrenal (HPA) axis, which is modulated by GC, and could be ascertained using an established GC risk score and DNA methylation (DNAm) of HPA axis genes.

METHODS

DNAm was quantified from buccal tissue (ECHO-NOVI) and from neonatal blood spots (ELGAN ECHO) via the EPIC microarray. Prenatal maternal characteristics, pregnancy complication, and neonatal medical complication data were collected from medical record review and maternal interviews.

RESULTS

The GC score was not associated with steroid exposure or BPD. However, six HPA genes involved in stress response regulation demonstrated differential methylation with antenatal steroid exposure; two CpGs within FKBP5 and POMC were differentially methylated with BPD severity. These findings were sex-specific in both cohorts; males had greater magnitude of differential methylation within these genes.

CONCLUSIONS

These findings suggest that BPD severity and antenatal steroids are associated with DNAm at some HPA genes in very preterm infants and the effects appear to be sex-, tissue-, and age-specific.

IMPACT

This study addresses bronchopulmonary dysplasia (BPD), an important health outcome among preterm neonates, and interrogates a commonly studied pathway, the hypothalamic-pituitary-adrenal (HPA) axis. The combination of BPD, the HPA axis, and epigenetic markers has not been previously reported. In this study, we found that BPD itself was not associated with epigenetic responses in the HPA axis in infants born very preterm; however, antenatal treatment with steroids was associated with epigenetic responses.

DNA methylation in necrotizing enterocolitis

Epigenetic modifications, such as DNA methylation, are enzymatically regulated processes that directly impact gene expression patterns. In early life, they are central to developmental programming and have also been implicated in regulating inflammatory responses. Research into the role of epigenetics in neonatal health is limited, but there is a growing body of literature related to the role of DNA methylation patterns and diseases of prematurity, such as the intestinal disease necrotizing enterocolitis (NEC). NEC is a severe intestinal inflammatory disease, but the key factors that precede disease development remain to be determined. This knowledge gap has led to a failure to design effective targeted therapies and identify specific biomarkers of disease. Recent literature has identified altered DNA methylation patterns in the stool and intestinal tissue of neonates with NEC. These findings provide the foundation for a new avenue in NEC research. In this review, we will provide a general overview of DNA methylation and then specifically discuss the recent literature related to methylation patterns in neonates with NEC. We will also discuss how DNA methylation is used as a biomarker for other disease states and how, with further research, methylation patterns may serve as potential biomarkers for NEC.

Toward a more holistic approach to the study of exposures and child outcomes

Aim: The current work was designed to demonstrate the application of the exposome framework in examining associations between exposures and children's long-term neurodevelopmental and behavioral outcomes. Methods: Longitudinal data were collected from birth through age 6 from 402 preterm infants. Three statistical methods were utilized to demonstrate the exposome framework: exposome-wide association study, cumulative exposure and machine learning models, with and without epigenetic data. Results: Each statistical approach answered a distinct research question regarding the impact of exposures on longitudinal child outcomes. Findings highlight associations between exposures, epigenetics and executive function. Conclusion: Findings demonstrate how an exposome-based approach can be utilized to understand relationships between internal (e.g., DNA methylation) and external (e.g., prenatal risk) exposures and long-term developmental outcomes in preterm children.

Epigenome-wide association study identifies neonatal DNA methylation associated with two-year attention problems in children born very preterm

Prior research has identified epigenetic predictors of attention problems in school-aged children but has not yet investigated these in young children, or children at elevated risk of attention problems due to preterm birth. The current study evaluated epigenome-wide associations between neonatal DNA methylation and attention problems at age 2 years in children born very preterm. Participants included 441 children from the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) Study, a multi-site study of infants born < 30 weeks gestational age. DNA methylation was measured from buccal swabs collected at NICU discharge using the Illumina MethylationEPIC Bead Array. Attention problems were assessed at 2 years of adjusted age using the attention problems subscale of the Child Behavior Checklist (CBCL). After adjustment for multiple testing, DNA methylation at 33 CpG sites was associated with child attention problems. Differentially methylated CpG sites were located in genes previously linked to physical and mental health, including several genes associated with ADHD in prior epigenome-wide and genome-wide association studies. Several CpG sites were located in genes previously linked to exposure to prenatal risk factors in the NOVI sample. Neonatal epigenetics measured at NICU discharge could be useful in identifying preterm children at risk for long-term attention problems and related psychiatric disorders, who could benefit from early prevention and intervention efforts.

Epigenetic age acceleration, neonatal morbidities, and neurobehavioral profiles in infants born very preterm

Epigenetic age acceleration is a risk factor for chronic diseases of ageing and may reflect aspects of biological ageing. However, few studies have examined epigenetic ageing during the early neonatal period in preterm infants, who are at heightened risk of developmental problems. We examined relationships between neonatal age acceleration, neonatal morbidities, and neurobehavioral domains among very preterm (<30 weeks gestation) infants to characterize whether infants with early morbidities or different neurobehavioral characteristics had accelerated or decelerated epigenetic ageing. This study uses data from the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) study, restricted to infants with data on variables assessed (n = 519). We used generalized estimating equations to test for differences in age acceleration associated with severe neonatal medical morbidities and neurobehavioral characteristics. We found that infants with neonatal morbidities, in particular, bronchopulmonary dysplasia (BPD), had accelerated epigenetic age - and some evidence that infants with hypertonicity and asymmetric reflexes had increased and decreased age acceleration, respectively. Adjustment for gestational age attenuated some associations, suggesting that the relationships observed may be driven by the duration of gestation. Our most robust finding shows that very preterm infants with neonatal morbidities (BPD in particular) exhibit age acceleration, but most neonatal neurobehavioral characteristics and morbidities are not associated with early life age acceleration. Lower gestational age at birth may be an upstream factor driving these associations.

Prospective epigenome and transcriptome analyses of cord and peripheral blood from preterm infants at risk of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a prevalent chronic lung disease of prematurity with limited treatment options. To uncover biomarkers of BPD risk, this study investigated epigenetic and transcriptomic signatures of prematurity at birth and during the neonatal period at day 14 and 28. Peripheral blood DNAs from preterm infants were applied to methylation arrays and cell-type composition was estimated by deconvolution. Covariate-adjusted robust linear regression elucidated BPD- and prolonged oxygen (≥ 14 days) exposure-associated CpGs. RNAs from cord and peripheral blood were sequenced, and differentially expressed genes (DEGs) for BPD or oxygen exposure were determined. Estimated neutrophil-lymphocyte ratios in peripheral blood at day 14 in BPD infants were significantly higher than nonBPD infants, suggesting an heightened inflammatory response in developing BPD. BPD-DEGs in cord blood indicated lymphopoiesis inhibition, altered Th1/Th2 responses, DNA damage, and organ degeneration. On day 14, BPD-associated CpGs were highly enriched in neutrophil activation, infection, and CD4 + T cell quantity, and BPD-DEGs were involved in DNA damage, cellular senescence, T cell homeostasis, and hyper-cytokinesis. On day 28, BPD-associated CpGs along with BPD-DEGs were enriched for phagocytosis, neurological disorder, and nucleotide metabolism. Oxygen supplementation markedly downregulated mitochondrial biogenesis genes and altered CpGs annotated to developmental genes. Prematurity-altered DNA methylation could cause abnormal lymphopoiesis, cellular assembly and cell cycle progression to increase BPD risk. Similar pathways between epigenome and transcriptome networks suggest coordination of the two in dysregulating leukopoiesis, adaptive immunity, and innate immunity. The results provide molecular insights into biomarkers for early detection and prevention of BPD.

Effects of DNA methylase inhibitors in a murine model of severe BPD

DNA methylation is necessary for developmental gene regulation, but adverse environments result in aberrant methylation and gene silencing. The current pilot study tested the hypothesis that treatment with DNA methylation inhibitors (decitabine; RG108) would improve alveolarization in a newborn murine model of severe bronchopulmonary dysplasia. Newborn mice exposed to maternal inflammation (LPS) and neonatal hyperoxia (85% O2) were treated with decitabine (p3, 0.1 mg/kg; p2, 4, 6, 0.1 mg/kg; or p2, 4, 6, 0.15 mg/kg) or RG108 (p3, 0.0013 mg/kg) delivered intranasally. Modest improvements in alveolarization were observed with decitabine, but no differences were observed with RG108. Attenuated phospho-SMAD2/3 levels and greater surfactant protein C protein levels compared to vehicle were observed with some tested doses. No detrimental side effects were observed with the doses used in this study. In summary, our pilot investigations identified a safe dose for intranasal administration of both methylation inhibitors and provides a foundation for further studies into methylation inhibitors in the context of neonatal lung injury.

Immuno-epigenetic signature derived in saliva associates with the encephalopathy of prematurity and perinatal inflammatory disorders

BACKGROUND

Preterm birth is closely associated with a phenotype that includes brain dysmaturation and neurocognitive impairment, commonly termed Encephalopathy of Prematurity (EoP), of which systemic inflammation is considered a key driver. DNA methylation (DNAm) signatures of inflammation from peripheral blood associate with poor brain imaging outcomes in adult cohorts. However, the robustness of DNAm inflammatory scores in infancy, their relation to comorbidities of preterm birth characterised by inflammation, neonatal neuroimaging metrics of EoP, and saliva cross-tissue applicability are unknown.

METHODS

Using salivary DNAm from 258 neonates (n = 155 preterm, gestational age at birth 23.28 - 34.84 weeks, n = 103 term, gestational age at birth 37.00 - 42.14 weeks), we investigated the impact of a DNAm surrogate for C-reactive protein (DNAm CRP) on brain structure and other clinically defined inflammatory exposures. We assessed i) if DNAm CRP estimates varied between preterm infants at term equivalent age and term infants, ii) how DNAm CRP related to different types of inflammatory exposure (maternal, fetal and postnatal) and iii) whether elevated DNAm CRP associated with poorer measures of neonatal brain volume and white matter connectivity.

RESULTS

Higher DNAm CRP was linked to preterm status (-0.0107 ± 0.0008, compared with -0.0118 ± 0.0006 among term infants; p < 0.001), as well as perinatal inflammatory diseases, including histologic chorioamnionitis, sepsis, bronchopulmonary dysplasia, and necrotising enterocolitis (OR range |2.00 | to |4.71|, p < 0.01). Preterm infants with higher DNAm CRP scores had lower brain volume in deep grey matter, white matter, and hippocampi and amygdalae (β range |0.185| to |0.218|). No such associations were observed for term infants. Association magnitudes were largest for measures of white matter microstructure among preterms, where elevated epigenetic inflammation associated with poorer global measures of white matter integrity (β range |0.206| to |0.371|), independent of other confounding exposures.

CONCLUSIONS

Inflammatory-related DNAm captures the allostatic load of inflammatory burden in preterm infants. Such DNAm measures complement biological and clinical metrics when investigating the determinants of neurodevelopmental differences.

Environmental influences on child health outcomes: cohorts of individuals born very preterm

The National Institutes of Health's Environmental influences on Child Health Outcomes (ECHO) Program was designed to address solution-oriented research questions about the links between children's early life environment and their risks of pre-, peri-, and post-natal complications, asthma, obesity, neurodevelopmental disorders, and positive health. Children born very preterm are at increased risk for many of the outcomes on which ECHO focuses, but the contributions of environmental factors to this risk are not well characterized. Three ECHO cohorts consist almost exclusively of individuals born very preterm. Data provided to ECHO from cohorts can be used to address hypotheses about (1) differential risks of chronic health and developmental conditions between individuals born very preterm and those born at term; (2) health disparities across social determinants of health; and (3) mechanisms linking early-life exposures and later-life outcomes among individuals born very preterm. IMPACT: The National Institutes of Health's Environmental Influences on Child Health Outcomes Program is conducting solution-oriented research on the links between children's environment and health. Three ECHO cohorts comprise study participants born very preterm; these cohorts have enrolled, to date, 1751 individuals born in 14 states in the U.S. in between April 2002 and March 2020. Extensive data are available on early-life environmental exposures and child outcomes related to neurodevelopment, asthma, obesity, and positive health. Data from ECHO preterm cohorts can be used to address questions about the combined effects of preterm birth and environmental exposures on child health outcomes.

Pathogenesis of Bronchopulmonary Dysplasia: Role of Oxidative Stress from 'Omics' Studies

Bronchopulmonary dysplasia (BPD) remains the most common respiratory complication of prematurity as younger and smaller infants are surviving beyond the immediate neonatal period. The recognition that oxidative stress (OS) plays a key role in BPD pathogenesis has been widely accepted since at least the 1980s. In this article, we examine the interplay between OS and genetic regulation and review 'omics' data related to OS in BPD. Data from animal models (largely models of hyperoxic lung injury) and from human studies are presented. Epigenetic and transcriptomic analyses have demonstrated several genes related to OS to be differentially expressed in murine models that mimic BPD as well as in premature infants at risk of BPD development and infants with established lung disease. Alterations in the genetic regulation of antioxidant enzymes is a common theme in these studies. Data from metabolomics and proteomics have also demonstrated the potential involvement of OS-related pathways in BPD. A limitation of many studies includes the difficulty of obtaining timely and appropriate samples from human patients. Additional 'omics' studies could further our understanding of the role of OS in BPD pathogenesis, which may prove beneficial for prevention and timely diagnosis, and aid in the development of targeted therapies.

Association of Pediatric Buccal Epigenetic Age Acceleration With Adverse Neonatal Brain Growth and Neurodevelopmental Outcomes Among Children Born Very Preterm With a Neonatal Infection

IMPORTANCE

Very preterm neonates (24-32 weeks' gestation) remain at a higher risk of morbidity and neurodevelopmental adversity throughout their lifespan. Because the extent of prematurity alone does not fully explain the risk of adverse neonatal brain growth or neurodevelopmental outcomes, there is a need for neonatal biomarkers to help estimate these risks in this population.

OBJECTIVES

To characterize the pediatric buccal epigenetic (PedBE) clock-a recently developed tool to measure biological aging-among very preterm neonates and to assess its association with the extent of prematurity, neonatal comorbidities, neonatal brain growth, and neurodevelopmental outcomes at 18 months of age.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study was conducted in 2 neonatal intensive care units of 2 hospitals in Toronto, Ontario, Canada. A total of 35 very preterm neonates (24-32 weeks' gestation) were recruited in 2017 and 2018, and neuroimaging was performed and buccal swab samples were acquired at 2 time points: the first in early life (median postmenstrual age, 32.9 weeks [IQR, 32.0-35.0 weeks]) and the second at term-equivalent age (TEA) at a median postmenstrual age of 43.0 weeks (IQR, 41.0-46.0 weeks). Follow-ups for neurodevelopmental assessments were completed in 2019 and 2020. All neonates in this cohort had at least 1 infection because they were originally enrolled to assess the association of neonatal infection with neurodevelopment. Neonates with congenital malformations, genetic syndromes, or congenital TORCH (toxoplasmosis, rubella, cytomegalovirus, herpes and other agents) infection were excluded.

EXPOSURES

The extent of prematurity was measured by gestational age at birth and PedBE age difference. PedBE age was computed using DNA methylation obtained from 94 age-informative CpG (cytosine-phosphate-guanosine) sites. PedBE age difference (weeks) was calculated by subtracting PedBE age at each time point from the corresponding postmenstrual age.

MAIN OUTCOMES AND MEASURES

Total cerebral volumes and cerebral growth during the neonatal intensive care unit period were obtained from magnetic resonance imaging scans at 2 time points: approximately the first 2 weeks of life and at TEA. Bayley Scales of Infant and Toddler Development, Third Edition, were used to assess neurodevelopmental outcomes at 18 months.

RESULTS

Among 35 very preterm neonates (21 boys [60.0%]; median gestational age, 27.0 weeks [IQR, 25.9-29.9 weeks]; 23 [65.7%] born extremely preterm [<28 weeks' gestation]), extremely preterm neonates had an accelerated PedBE age compared with neonates born at a later gestational age (β = 9.0; 95% CI, 2.7-15.3; P = .01). An accelerated PedBE age was also associated with smaller cerebral volumes (β = -5356.8; 95% CI, -6899.3 to -2961.7; P = .01) and slower cerebral growth (β = -2651.5; 95% CI, -5301.2 to -1164.1; P = .04); these associations remained significant after adjusting for clinical neonatal factors. These findings were significant at TEA but not earlier in life. Similarly, an accelerated PedBE age at TEA was associated with lower cognitive (β = -0.4; 95% CI, -0.8 to -0.03; P = .04) and language (β = -0.6; 95% CI, -1.1 to -0.06; P = .02) scores at 18 months.

CONCLUSIONS AND RELEVANCE

This cohort study of very preterm neonates suggests that biological aging may be associated with impaired brain growth and neurodevelopmental outcomes. The associations between epigenetic aging and adverse neonatal brain health warrant further attention.

Neonatal frontal-limbic connectivity is associated with externalizing behaviours in toddlers with Congenital Heart Disease

Children with Congenital Heart Disease (CHD) are at increased risk of neurodevelopmental impairments. The neonatal antecedents of impaired behavioural development are unknown. 43 infants with CHD underwent presurgical brain diffusion-weighted MRI [postmenstrual age at scan median (IQR) = 39.29 (38.71-39.71) weeks] and a follow-up assessment at median age of 22.1 (IQR 22.0-22.7) months in which parents reported internalizing and externalizing problem scores on the Child Behaviour Checklist. We constructed structural brain networks from diffusion-weighted MRI and calculated edge-wise structural connectivity as well as global and local brain network features. We also calculated presurgical cerebral oxygen delivery, and extracted perioperative variables, socioeconomic status at birth and a measure of cognitively stimulating parenting. Lower degree in the right inferior frontal gyrus (partial ρ = -0.687, p < 0.001) and reduced connectivity in a frontal-limbic sub-network including the right inferior frontal gyrus were associated with higher externalizing problem scores. Externalizing problem scores were unrelated to neonatal clinical course or home environment. However, higher internalizing problem scores were associated with earlier surgery in the neonatal period (partial ρ = -0.538, p = 0.014). Our results highlight the importance of frontal-limbic networks to the development of externalizing behaviours and provide new insights into early antecedents of behavioural impairments in CHD.

Analysis of Neonatal Neurobehavior and Developmental Outcomes Among Preterm Infants

IMPORTANCE

The ability to identify poor outcomes and treatable risk factors among very preterm infants remains challenging; improving early risk detection and intervention targets to potentially address developmental and behavioral delays is needed.

OBJECTIVE

To determine associations between neonatal neurobehavior using the Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scale (NNNS), neonatal medical risk, and 2-year outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter cohort enrolled infants born at less than 30 weeks' gestation at 9 US university-affiliated NICUs. Enrollment was conducted from April 2014 to June 2016 with 2-year adjusted age follow-up assessment. Data were analyzed from December 2019 to January 2022.

EXPOSURES

Adverse medical and psychosocial conditions; neurobehavior.

MAIN OUTCOMES AND MEASURES

Bayley Scales of Infant and Toddler Development, third edition (Bayley-III), cognitive, language, and motor scores of less than 85 and Child Behavior Checklist (CBCL) T scores greater than 63. NNNS examinations were completed the week of NICU discharge, and 6 profiles of neurobehavior were identified by latent profile analysis. Generalized estimating equations tested associations among NNNS profiles, neonatal medical risk, and 2-year outcomes while adjusting for site, maternal socioeconomic and demographic factors, maternal psychopathology, and infant sex.

RESULTS

A total of 679 enrolled infants had medical and NNNS data; 2-year follow-up data were available for 479 mothers and 556 infants (mean [SD] postmenstrual age at birth, 27.0 [1.9] weeks; 255 [45.9%] female). Overall, 268 mothers (55.9%) were of minority race and ethnicity, and 127 (26.6%) lived in single-parent households. The most common neonatal medical morbidity was BPD (287 [51.7%]). Two NNNS behavior profiles, including 157 infants, were considered high behavioral risk. Infants with at least 2 medical morbidities (n = 123) were considered high medical risk. Infants with high behavioral and high medical risk were 4 times more likely to have Bayley-III motor scores less than 85 compared with those with low behavioral and low medical risk (adjusted relative risk [aRR], 4.1; 95% CI, 2.9-5.1). Infants with high behavioral and high medical risk also had increased risk for cognitive scores less than 85 (aRR, 2.7; 95% CI, 1.8-3.4). Only infants with high behavioral and low medical risk were in the clinical range for CBCL internalizing and total problem scores (internalizing: aRR, 2.3; 95% CI, 1.1-4.5; total: aRR, 2.5; 95% CI, 1.2-4.4).

CONCLUSIONS AND RELEVANCE

In this study, high-risk neonatal neurobehavioral patterns at NICU discharge were associated with adverse cognitive, motor, and behavioral outcomes at 2 years. Used in conjunction with medical risk, neonatal neurobehavioral assessments could enhance identification of infants at highest risk for delay and offer opportunities to provide early, targeted therapies.

Epigenome-wide association study of bronchopulmonary dysplasia in preterm infants: results from the discovery-BPD program

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a lung disease in premature infants caused by therapeutic oxygen supplemental and characterized by impaired pulmonary development which persists into later life. While advances in neonatal care have improved survival rates of premature infants, cases of BPD have been increasing with limited therapeutic options for prevention and treatment. This study was designed to explore the relationship between gestational age (GA), birth weight, and estimated blood cell-type composition in premature infants and to elucidate early epigenetic biomarkers associated with BPD.

METHODS

Cord blood DNA from preterm neonates that went on to develop BPD (n = 14) or not (non-BPD, n = 93) was applied to Illumina 450 K methylation arrays. Blood cell-type compositions were estimated using DNA methylation profiles. Multivariable robust regression analysis elucidated CpGs associated with BPD risk. cDNA microarray analysis of cord blood RNA identified differentially expressed genes in neonates who later developed BPD.

RESULTS

The development of BPD and the need for oxygen supplementation were strongly associated with GA (BPD, p < 1.0E-04; O2 supplementation, p < 1.0E-09) and birth weight (BPD, p < 1.0E-02; O2 supplementation, p < 1.0E-07). The estimated nucleated red blood cell (NRBC) percent was negatively associated with birth weight and GA, positively associated with hypomethylation of the tobacco smoke exposure biomarker cg05575921, and high-NRBC blood samples displayed a hypomethylation profile. Epigenome-wide association study (EWAS) identified 38 (Bonferroni) and 275 (false discovery rate 1%) differentially methylated CpGs associated with BPD. BPD-associated CpGs in cord blood were enriched for lung maturation and hematopoiesis pathways. Stochastic epigenetic mutation burden at birth was significantly elevated among those who developed BPD (adjusted p = 0.02). Transcriptome changes in cord blood cells reflected cell cycle, development, and pulmonary disorder events in BPD.

CONCLUSIONS

While results must be interpreted with caution because of the small size of this study, NRBC content strongly impacted DNA methylation profiles in preterm cord blood and EWAS analysis revealed potential insights into biological pathways involved in BPD pathogenesis.

DNA methylation in relation to gestational age and brain dysmaturation in preterm infants

Preterm birth is associated with dysconnectivity of structural brain networks and is a leading cause of neurocognitive impairment in childhood. Variation in DNA methylation is associated with early exposure to extrauterine life but there has been little research exploring its relationship with brain development. Using genome-wide DNA methylation data from the saliva of 258 neonates, we investigated the impact of gestational age on the methylome and performed functional analysis to identify enriched gene sets from probes that contributed to differentially methylated probes or regions. We tested the hypothesis that variation in DNA methylation could underpin the association between low gestational age at birth and atypical brain development by linking differentially methylated probes with measures of white matter connectivity derived from diffusion MRI metrics: peak width skeletonized mean diffusivity, peak width skeletonized fractional anisotropy and peak width skeletonized neurite density index. Gestational age at birth was associated with widespread differential methylation at term equivalent age, with genome-wide significant associations observed for 8870 CpG probes (P < 3.6 × 10-8) and 1767 differentially methylated regions. Functional analysis identified 14 enriched gene ontology terms pertaining to cell-cell contacts and cell-extracellular matrix contacts. Principal component analysis of probes with genome-wide significance revealed a first principal component that explained 23.5% of the variance in DNA methylation, and this was negatively associated with gestational age at birth. The first principal component was associated with peak width of skeletonized mean diffusivity (β = 0.349, P = 8.37 × 10-10) and peak width skeletonized neurite density index (β = 0.364, P = 4.15 × 10-5), but not with peak width skeletonized fraction anisotropy (β = -0.035, P = 0.510); these relationships mirrored the imaging metrics' associations with gestational age at birth. Low gestational age at birth has a profound and widely distributed effect on the neonatal saliva methylome that is apparent at term equivalent age. Enriched gene ontology terms related to cell-cell contacts reveal pathways that could mediate the effect of early life environmental exposures on development. Finally, associations between differential DNA methylation and image markers of white matter tract microstructure suggest that variation in DNA methylation may provide a link between preterm birth and the dysconnectivity of developing brain networks that characterizes atypical brain development in preterm infants.

DNA Methylation Pattern of CALCA and CALCB in Extremely Premature Infants with Monochorionic Triplets after Single-Embryo Transfer

Compared with full-term peers, premature infants are more likely to suffer from neonatal diseases and death. Variations in DNA methylation may affect these pathological processes. Calcitonin gene-related peptide (CGRP) plays a complex and diversified role in reproduction and chronic inflammation, and participates in the functional maintenance of vascular adaptation and trophoblast cells during pregnancy. Here, premature live births with single-chorionic triple embryos after single-embryo transfer were used as research objects, while full-term infants with double embryos and double-chorionic twins were used as controls. DNA was extracted from umbilical cord tissues for pyrosequencing to detect the methylation level of CpG island in CGRP promoter region. The average values of CGRP methylation in the umbilical cord tissues of very premature fetuses were higher than that of normal controls obtained from the databases. Immunofluorescence results showed that the expression of αCGRP was decreased in the blood vessel wall of the umbilical cord of monozygotic triplets, especially in death cases, while the βCGRP had a compensatory expression. In conclusion, our findings suggest that hypermethylation of CGRP might be considered as an important cause of serious neonatal morbidities.

NEOage clocks - epigenetic clocks to estimate post-menstrual and postnatal age in preterm infants

Epigenetic clocks based on DNA methylation (DNAm) can accurately predict chronological age and are thought to capture biological aging. A variety of epigenetic clocks have been developed for different tissue types and age ranges, but none have focused on postnatal age prediction for preterm infants. Epigenetic estimators of biological age might be especially informative in epidemiologic studies of neonates since DNAm is highly dynamic during the neonatal period and this is a key developmental window. Additionally, markers of biological aging could be particularly important for those born preterm since they are at heightened risk of developmental impairments. We aimed to fill this gap by developing epigenetic clocks for neonatal aging in preterm infants. As part of the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) study, buccal cells were collected at NICU discharge to profile DNAm levels in 542 very preterm infants. We applied elastic net regression to identify four epigenetic clocks (NEOage Clocks) predictive of post-menstrual and postnatal age, compatible with the Illumina EPIC and 450K arrays. We observed high correlations between predicted and reported ages (0.93 - 0.94) with root mean squared errors (1.28 - 1.63 weeks). Epigenetic estimators of neonatal aging in preterm infants can be useful tools to evaluate biological maturity and associations with neonatal and long-term morbidities.

Prenatal risk factors and neonatal DNA methylation in very preterm infants

BACKGROUND

Prenatal risk factors are related to poor health and developmental outcomes for infants, potentially via epigenetic mechanisms. We tested associations between person-centered prenatal risk profiles, cumulative prenatal risk models, and epigenome-wide DNA methylation (DNAm) in very preterm neonates.

METHODS

We studied 542 infants from a multi-center study of infants born < 30 weeks postmenstrual age. We assessed 24 prenatal risk factors via maternal report and medical record review. Latent class analysis was used to define prenatal risk profiles. DNAm was quantified from neonatal buccal cells using the Illumina MethylationEPIC Beadarray.

RESULTS

We identified three latent profiles of women: a group with few risk factors (61%) and groups with elevated physical (26%) and psychological (13%) risk factors. Neonates born to women in higher risk subgroups had differential DNAm at 2 CpG sites. Higher cumulative prenatal risk was associated with methylation at 15 CpG sites, 12 of which were located in genes previously linked to physical and mental health and neurodevelopment.

CONCLUSION

We observed associations between prenatal risk factors and DNAm in very preterm infants using both person-centered and cumulative risk approaches. Epigenetics offers a potential biological indicator of prenatal risk exposure.