Epigenome-wide analysis identifies genes and pathways linked to acoustic cry variation in preterm infants

BACKGROUND

Preterm birth places infants at higher risk of adverse long-term behavioral and cognitive outcomes. Combining biobehavioral measures and molecular biomarkers may improve tools to predict the risk of long-term developmental delays.

METHODS

The Neonatal Neurobehavior and Outcomes in Very Preterm Infants study was conducted at nine neonatal intensive care units between April 2014 and June 2016. Cries were recorded and buccal swabs collected during the neurobehavioral exam. Cry episodes were extracted and analyzed using a computer system and the data were summarized using factor analysis. Genomic DNA was extracted from buccal swabs, quantified using the Qubit Fluorometer, and aliquoted into standardized concentrations. DNA methylation was measured with the Illumina MethylationEPIC BeadArray, and an epigenome-wide association study was performed using cry factors (n = 335).

RESULTS

Eighteen CpGs were associated with the cry factors at genome-wide significance (α = 7.08E - 09). Two CpG sites, one intergenic and one linked to gene TCF3 (important for B and T lymphocyte development), were associated with acoustic measures of cry energy. Increased methylation of TCF3 was associated with a lower energy-related cry factor. We also found that pitch (F₀) and hyperpitch (F₀ > 1 kHz) were associated with DNA methylation variability at 16 CpG sites.

CONCLUSIONS

Acoustic cry characteristics are related to variation in DNA methylation in preterm infants.

IMPACT

Preterm birth is a major public health problem and its long-term impact on health is not well understood. Cry acoustics, related to prematurity, has been linked to a variety of medical conditions. Biobehavioral measures and molecular biomarkers can improve prediction tools for long-term developmental risks of preterm birth. Variation in epigenetic modulation in preterm infants provides a potential link between preterm birth and unfavorable developmental outcomes.

Phenobarbital and Clonidine as Secondary Medications for Neonatal Opioid Withdrawal Syndrome

BACKGROUND AND OBJECTIVES

Despite the neonatal opioid withdrawal syndrome (NOWS) epidemic in the United States, evidence is limited for pharmacologic management when first-line opioid medications fail to control symptoms. The objective with this study was to evaluate outcomes of infants receiving secondary therapy with phenobarbital compared with clonidine, in combination with morphine, for the treatment of NOWS.

METHODS

We performed a retrospective cohort study of infants with NOWS from 30 hospitals. The primary outcome measures were the length of hospital stay, duration of opioid treatment, and peak morphine dose. Outcomes were compared by group by using analysis of variance and multivariable linear regression controlling for relevant confounders.

RESULTS

Of 563 infants with NOWS treated with morphine, 32% (n = 180) also received a secondary medication. Seventy-two received phenobarbital and 108 received clonidine. After adjustment for covariates, length of hospital stay was 10 days shorter, and, in some models, duration of morphine treatment was 7.5 days shorter in infants receiving phenobarbital compared with those receiving clonidine, with no difference in peak morphine dose. Infants were more likely to be discharged from the hospital on phenobarbital than clonidine (78% vs 29%, P < .0001).

CONCLUSIONS

Among infants with NOWS receiving morphine and secondary therapy, those treated with phenobarbital had shorter length of hospital stay and shorter morphine treatment duration than clonidine-treated infants but were discharged from the hospital more often on secondary medication. Further investigation is warranted to determine if the benefits of shorter hospital stay and shorter duration of morphine therapy justify the possible neurodevelopmental consequences of phenobarbital use in infants with NOWS.

Site-Level Variation in the Characteristics and Care of Infants With Neonatal Opioid Withdrawal

BACKGROUND AND OBJECTIVES

Variation in pediatric medical care is common and contributes to differences in patient outcomes. Site-to-site variation in the characteristics and care of infants with neonatal opioid withdrawal syndrome (NOWS) has yet to be quantified. Our objective was to describe site-to-site variation in maternal-infant characteristics, infant management, and outcomes for infants with NOWS.

METHODS

Cross-sectional study of 1377 infants born between July 1, 2016, and June 30, 2017, who were ≥36 weeks' gestation, with NOWS (evidence of opioid exposure and NOWS scoring within the first 120 hours of life) born at or transferred to 1 of 30 participating hospitals nationwide. Site-to-site variation for each parameter within the 3 domains was measured as the range of individual site-level means, medians, or proportions.

RESULTS

Sites varied widely in the proportion of infants whose mothers received adequate prenatal care (31.3%-100%), medication-assisted treatment (5.9%-100%), and prenatal counseling (1.9%-75.5%). Sites varied in the proportion of infants with toxicology screening (50%-100%) and proportion of infants receiving pharmacologic therapy (6.7%-100%), secondary medications (1.1%-69.2%), and nonpharmacologic interventions including fortified feeds (2.9%-90%) and maternal breast milk (22.2%-83.3%). The mean length of stay varied across sites (2-28.8 days), as did the proportion of infants discharged with their parents (33.3%-91.1%).

CONCLUSIONS

Considerable site-to-site variation exists in all 3 domains. The magnitude of the observed variation makes it unlikely that all infants are receiving efficient and effective care for NOWS. This variation should be considered in future clinical trial development, practice implementation, and policy development.

Neonatal Abstinence Syndrome Severity Index Predicts 18-Month Neurodevelopmental Outcome in Neonates Randomized to Morphine or Methadone

OBJECTIVE

To develop an index to determine which opioid-exposed neonates have the most severe neonatal abstinence syndrome (NAS).

STUDY DESIGN

Full-term neonates with NAS (n = 116) from mothers maintained on methadone or buprenorphine were enrolled from 8 sites into a randomized clinical trial of morphine vs methadone. Ninety-nine (85%) were evaluated at hospital discharge using the NICU Network Neurobehavioral Scale (NNNS). At 18 months, 83 of 99 (83.8%) were evaluated with the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III), and 77 of 99 (77.7%) were evaluated with the Child Behavior Checklist (CBCL).

RESULTS

Cluster analysis was used to define high (n = 21) and low (n = 77) NAS severity. Compared with infants in the low NAS severity cluster, infants in the high NAS severity cluster had a longer length of stay (P < .001), longer length of stay due to NAS (P < .001), longer duration of treatment due to NAS (P < .001), and higher total dose of the study drug (P < .001) and were more likely to have received phenobarbital (P < .001), to have been treated with morphine (P = .020), and to have an atypical NNNS profile (P = .005). The 2 groups did not differ in terms of maximum Finnegan score. At 18 months, in unadjusted analyses, compared with the high-severity cluster, the low-severity cluster had higher scores on the Bayley-III Cognitive (P = .013), Language (P < .001), and Motor (P = .041) composites and less total behavior problems on the CBCL (P = .028). In adjusted analyses, the difference in the Bayley-III Language composite remained (P = .013).

CONCLUSIONS

Presumptive measures of NAS severity can be aggregated to develop an index that predicts developmental outcomes at age 18 months.

Behavior Problems During Early Childhood in Children With Prenatal Methamphetamine Exposure

BACKGROUND AND OBJECTIVES

The effects of in utero methamphetamine exposure on behavioral problems in school-aged children are unclear. Our objective for this study was to evaluate behavior problems in children at aged 3, 5, and 7.5 years who were prenatally exposed to methamphetamine.

METHODS

Subjects were enrolled in the Infant Development, Environment, and Lifestyle study, a longitudinal prospective study of prenatal methamphetamine exposure and child outcomes. Exposed and comparison groups were matched on birth weight, race, education, and health insurance.  At ages 3, 5, and 7.5 years, 339 children (171 exposed) were assessed for behavior problems by using the Child Behavior Checklist. Generalized estimating equations were used to determine the effects of prenatal methamphetamine exposure, age, and the interaction of exposure and age on behavior problems. Caregiver psychological symptoms were assessed by using the Brief Symptom Inventory.

RESULTS

Analyses adjusted for covariates revealed that relative to age 3, children at 5 years had less externalizing and aggressive behavior and more internalizing behavior, somatic complaints, and withdrawn behavior.  By age 7.5, aggressive behavior continued to decrease, attention problems increased and withdrawn behavior decreased. There were no main effects for methamphetamine exposure and no interactions of exposure and age.  Caregiver psychological symptoms predicted all behavior problems and the quality of the home predicted externalizing problems and externalizing syndrome scores.

CONCLUSIONS

Behavioral effects longitudinally from ages 3 to 7.5 years were not associated with prenatal methamphetamine exposure, whereas caregiver psychological symptoms and the quality of the home were predictors of behavior problems.

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

Background

Infants born very preterm are more likely to experience neonatal morbidities compared to their term peers. Variations in DNA methylation (DNAm) associated with these morbidities may yield novel information about the processes impacted by these morbidities.

Methods

This study included 532 infants born < 30 weeks gestation, participating in the Neonatal Neurobehavior and Outcomes in Very Preterm Infants study. We used a neonatal morbidity risk score, which was an additive index of the number of morbidities experienced during the NICU stay, including bronchopulmonary dysplasia (BPD), severe brain injury, serious neonatal infections, and severe retinopathy of prematurity. DNA was collected from buccal cells at discharge from the NICU, and DNAm was measured using the Illumina MethylationEPIC. We tested for differential methylation in association with the neonatal morbidity risk score then tested for differentially methylated regions (DMRs) and overrepresentation of biological pathways.

Results

We identified ten differentially methylated CpGs (α Bonferroni-adjusted for 706,278 tests) that were associated with increasing neonatal morbidity risk scores at three intergenic regions and at HPS4, SRRD, FGFR1OP, TNS3, TMEM266, LRRC3B, ZNF780A, and TENM2. These mostly followed dose–response patterns, for 8 CpGs increasing DNAm associated with increased numbers of morbidities, while for 2 CpGs the risk score was associated with decreasing DNAm. BPD was the most substantial contributor to differential methylation. We also identified seven potential DMRs and over-representation of genes involved in Wnt signaling; however, these results were not significant after Bonferroni adjustment for multiple testing.

Conclusions

Neonatal DNAm, within genes involved in fibroblast growth factor activities, cellular invasion and migration, and neuronal signaling and development, are sensitive to the neonatal health complications of prematurity. We hypothesize that these epigenetic features may be representative of an integrated marker of neonatal health and development and are promising candidates to integrate with clinical information for studying developmental impairments in childhood.

Early external-environmental and internal-health predictors of risky sexual and aggressive behavior in adolescence: An integrative approach

External predictive adaptive response (PAR) models assume that developmental exposures to stress carry predictive information about the future state of the environment, and that development of a faster life history (LH) strategy in this context functions to match the individual to this expected harsh state. More recently internal PAR models have proposed that early somatic condition (i.e., physical health) critically regulates development of LH strategies to match expected future somatic condition. Here we test the integrative hypothesis that poor physical health mediates the relation between early adversity and faster LH strategies. Data were drawn from a longitudinal study (birth to age 16; N = 1,388) of mostly African American participants with prenatal substance exposure. Results demonstrated that both external environmental conditions early in life (prenatal substance exposure, socioeconomic adversity, caregiver distress/depression, and adverse family functioning) and internal somatic condition during preadolescence (birthweight/gestational age, physical illness) uniquely predicted the development of faster LH strategies in adolescence (as indicated by more risky sexual and aggressive behavior). Consistent with the integrative hypothesis, the effect of caregiver distress/depression on LH strategy was mostly mediated by worse physical health. Discussion highlights the implications of these findings for theory and research on stress, development, and health.

Neurodevelopmental Outcomes of Neonates Randomized to Morphine or Methadone for Treatment of Neonatal Abstinence Syndrome

OBJECTIVE

To evaluate the effects of pharmacologic treatment of neonatal abstinence syndrome on neurodevelopmental outcome from a randomized, controlled trial.

STUDY DESIGN

Eight sites enrolled 116 full-term newborn infants with neonatal abstinence syndrome born to mothers maintained on methadone or buprenorphine into a randomized trial of morphine vs methadone. Ninety-nine infants (85%) were evaluated at hospital discharge using the NICU Network Neurobehavioral Scale. At 18 months, 83 of 99 infants (83.8%) were evaluated with the Bayley Scales of Infant and Toddler Development-Third Edition and 77 of 99 (77.7%) with the Child Behavior Checklist (CBCL).

RESULTS

Primary analyses showed no significant differences between treatment groups on the NICU Network Neurobehavioral Scale, Bayley Scales of Infant and Toddler Development-Third Edition, or CBCL. However in post hoc analyses, we found differences by atypical NICU Network Neurobehavioral Scale profile on the CBCL. Infants receiving adjunctive phenobarbital had lower Bayley Scales of Infant and Toddler Development-Third Edition scores and more behavior problems on the CBCL. In adjusted analyses, internalizing and total behavior problems were associated with use of phenobarbital (P = .03; P = .04), maternal psychological distress (measured by the Brief Symptom Inventory) (both P < .01), and infant medical problems (both P = .02). Externalizing problems were associated with maternal psychological distress (P < .01) and continued maternal substance use (P < .01).

CONCLUSIONS

Infants treated with either morphine or methadone had similar short-term and longer term neurobehavioral outcomes. Neurodevelopmental outcome may be related to the need for phenobarbital, overall health of the infant, and postnatal caregiving environment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01958476.

Psychosocial and medical adversity associated with neonatal neurobehavior in infants born before 30 weeks gestation

BACKGROUND

Psychosocial adversity escalates medical risk for poor outcomes in infants born <30 weeks gestation. Neonatal neurobehavior and maternal psychological and socioenvironmental assessments may identify the earliest specific intervention needs. We hypothesized that maternal prenatal anxiety, depression, and adverse medical and socioenvironmental conditions would be associated with less optimal neonatal neurobehavior at neonatal intensive care unit (NICU) discharge.

METHODS

We studied 665 infants at 9 university NICUs. Risk indices of socioenvironmental, maternal, and neonatal medical factors were obtained from standardized, structured maternal interviews and medical record reviews. Brain injuries were classified by consensus ultrasonogram readings. NICU Network Neurobehavioral Scale (NNNS) exams were conducted at NICU discharge.

RESULTS

On the NNNS, generalized estimating equations indicated infants of mothers with prenatal anxiety had less optimal attention, and those born to mothers with prenatal depression had increased lethargy. Maternal medical complications predicted suboptimal reflexes. Socioenvironmental risk predicted lower self-regulation and movement quality. Infants with more severe neonatal medical complications had lower attention, increased lethargy, and suboptimal reflexes.

CONCLUSIONS

Combined information from the observed associations among adverse prenatal maternal medical and psychosocial conditions, and neonatal complications may assist in the early identification of infants at elevated neurobehavioral risk.

Social Stress-Related Epigenetic Changes Associated With Increased Heart Rate Variability in Infants

Early life stress can result in persistent alterations of an individual’s stress regulation through epigenetic modifications. Epigenetic alteration of the NR3C1 gene is associated with changes in the stress response system during infancy as measured by cortisol reactivity. Although autonomic nervous system (ANS) reactivity is a key component of the stress response, we have a limited understanding of the effects of NR3C1 DNA methylation on ANS reactivity. To examine this relation, ANS stress responses of term, 4–5-month-old healthy infants were elicited using the face-to-face still-face paradigm, which involved five, 2-min episodes. Two of these episodes were the “still-face” in which the mother was non-responsive to her infant. EKG was acquired continuously and analyzed in 30 s-intervals. Cheek swabs were collected, and DNA was extracted from buccal cells. Respiratory sinus arrhythmia (RSA) was measured as heart rate variability (HRV). Mean HRV was calculated for each 30-s “face to face” episode. DNA methylation of NR3C1 was calculated using bisulfite pyrosequencing. Percent DNA methylation was computed for each of the 13 NR3C1 CpG sites. The relations between mean HRV for each “face to face” episode and percent DNA methylation was examined averaged over CpG sites 1–6 and 7–13 and at each individual CpG site. Higher HRV at baseline, first reunion, and second still-face was related to greater methylation of NR3C1 CpG sites 1–6. Higher HRV at the second reunion was related to greater methylation of NR3C1 CpG sites 12 and 13. These data provide evidence that increased methylation of NR3C1 at CpG sites 12 and 13 are associated with increased activation of parasympathetic pathways as represented by increased HRV.

Prenatal Opioid Exposure: Neurodevelopmental Consequences and Future Research Priorities

Neonatal opioid withdrawal syndrome (NOWS) has risen in prevalence from 1.2 per 1000 births in 2000 to 5.8 per 1000 births in 2012. Symptoms in neonates may include high-pitched cry, tremors, feeding difficulty, hypertonia, watery stools, and breathing problems. However, little is known about the neurodevelopmental consequences of prenatal opioid exposure in infancy, early childhood, and middle childhood. Even less is known about the cognitive, behavioral, and academic outcomes of children who develop NOWS. We review the state of the literature on the neurodevelopmental consequences of prenatal opioid exposure with a particular focus on studies in which NOWS outcomes were examined. Aiming to reduce the incidence of prenatal opioid exposure in the near future, we highlight the need for large studies with prospectively recruited participants and longitudinal designs, taking into account confounding factors such as socioeconomic status, institutional variations in care, and maternal use of other substances, to independently assess the full impact of NOWS. As a more immediate solution, we provide an agenda for future research that leverages the National Institutes of Health Environmental Influences on Child Health Outcomes program to address many of the serious methodologic gaps in the literature, and we answer key questions regarding the short- and long-term neurodevelopmental health of children with prenatal opioid exposure.

DNA methylation of NR3c1 in infancy: Associations between maternal caregiving and infant sex

Caregivers play a critical role in scaffolding infant stress reactivity and regulation, but the mechanisms by which this scaffolding occurs is unclear. Animal models strongly suggest that epigenetic processes, such as DNA methylation, are sensitive to caregiving behaviors and, in turn, offspring stress reactivity. We examined the direct effects of caregiving behaviors on DNA methylation in infants and infant stress reactivity. Infants and mothers (N = 128) were assessed during a free play when infants were 5 months old. Maternal responsiveness and appropriate touch were coded. and infant buccal epithelial cells were sampled to assess for DNA methylation of the glucocorticoid receptor gene, NR3c1 exon 1F. Infant cortisol reactivity was assessed in response to the still-face paradigm. Greater levels of maternal responsiveness and appropriate touch were related to less DNA methylation of specific regions in NR3c1 exon 1F, but only for females. There was no association with maternal responsiveness and appropriate touch or DNA methylation of NR3c1 exon 1F on prestress cortisol or cortisol reactivity. Our results are discussed in relation to programming models that implicate maternal care as an important factor in programing infant stress reactivity.

Epigenome-wide Analysis Identifies Genes and Pathways Linked to Neurobehavioral Variation in Preterm Infants

Neonatal molecular biomarkers of neurobehavioral responses (measures of brain-behavior relationships), when combined with neurobehavioral performance measures, could lead to better predictions of long-term developmental outcomes. To this end, we examined whether variability in buccal cell DNA methylation (DNAm) associated with neurobehavioral profiles in a cohort of infants born less than 30 weeks postmenstrual age (PMA) and participating in the Neonatal Neurobehavior and Outcomes in Very Preterm Infants (NOVI) Study (N = 536). We tested whether epigenetic age, age acceleration, or DNAm levels at individual loci differed between infants based on their NICU Network Neurobehavioral Scale (NNNS) profile classifications. We adjusted for recruitment site, infant sex, PMA, and tissue heterogeneity. Infants with an optimally well-regulated NNNS profile had older epigenetic age compared to other NOVI infants (β1 = 0.201, p-value = 0.026), but no significant difference in age acceleration. In contrast, infants with an atypical NNNS profile had differential methylation at 29 CpG sites (FDR < 10%). Some of the genes annotated to these CpGs included PLA2G4E, TRIM9, GRIK3, and MACROD2, which have previously been associated with neurological structure and function, or with neurobehavioral disorders. These findings contribute to the existing evidence that neonatal epigenetic variations may be informative for infant neurobehavior.

Stimulants: How big is the problem and what are the effects of prenatal exposure?

Globally, cocaine use increased by 7%-18.2 million people in 2016 or 0.4% of the world population aged 15-64. In 2016, over 34 million (0.7%) people aged 15-64 used amphetamines and a further 0.4% used MDMA (Ecstasy). Women of child bearing age worldwide are increasingly using and becoming dependent on stimulants; and are, in turn, more vulnerable to sexually transmitted diseases, sexual violence, unplanned pregnancies and mental health problems. Stimulant use during pregnancy increases obstetric complications for the mother, increases the rate of preterm birth and decreases birth weight, length and head circumference for the exposed infant. No consistent signs of neonatal abstinence syndrome requiring pharmacological treatment have been identified for cocaine or methamphetamine, however, infants exposed to one or both drugs exhibit disorganized neurobehaviour at birth. Increased efforts worldwide are needed to determine the extent of maternal stimulant use and to prevent or identify and treat substance use early during pregnancy.

Developmental trajectories of autonomic functioning in autism from birth to early childhood

Deficits in social engagement emerge in autism during the infant and toddler period and may be related to emotion regulation and stress response systems. This study examined patterns of growth in autonomic functioning related to autism diagnosis and addresses the hypothesis that there are differences in autonomic functioning related to autism in infancy. Heart rate (HR) and respiratory sinus arrhythmia (RSA) were measured at 8 time points from 1 to 72 months of age in infants later diagnosed with autism (n = 12) and a non-autistic comparison group (n = 106). Multilevel models were used to describe the developmental course of HR and RSA and to test the effect of autism diagnosis on growth trajectories. Both groups showed an expected age-related decrease in HR and increase in RSA. Groups did not differ in the rate of decrease of HR over time. However, infants with autism demonstrated a smaller linear increase in RSA, indicating slower growth in RSA over time in comparison to controls. These results suggest that differences in physiological regulation may develop with age in autism. The slowed RSA growth in autism was most evident after 18 months of age, at a time when behavioral symptoms become prominent. This is consistent with the view that RSA is a marker of functional status in autism rather than a cause of social deficits in autism.

Early life stress and environmental influences on the neurodevelopment of children with prenatal opioid exposure

Prenatal opioid exposure has reached epidemic proportions. In the last 10 years, there has been a 242% increase in the number of babies born with the drug withdrawal syndrome known as Neonatal Opioid Withdrawal Syndrome (NOWS). Developmental outcome studies of infants with prenatal opioid exposure are limited by methodological issues including small sample sizes and lack of control for confounding variables such as exposure to poverty and maternal psychopathology. Thus, there is a critical gap in the literature that limits our ability to predict short-term effects of opioid exposure. Here we review direct neurotoxic, indirect, and stress-related pathophysiologies of prenatal opioid exposure. We describe the literature on short and long-term neurodevelopmental outcomes of children with prenatal opioid exposure, highlighting sex differences and the role of early life stress. We conclude by prioritizing avenues for future research for this group of underserved women and their children at risk for neurodevelopmental delays.

Epigenetic Programming by Maternal Behavior in the Human Infant

: media-1vid110.1542/5804912859001PEDS-VA_2017-1890Video Abstract OBJECTIVES: We sought to determine if variations in maternal care alter DNA methylation in term, healthy, 5-month-old infants. This work was based on landmark studies in animal models demonstrating that nurturing care by dams would alter their newborns' stress responses through epigenetic mechanisms. We used breastfeeding as a proxy for animal maternal behavior. We hypothesized alterations in DNA methylation of the glucocorticoid receptor gene and less hypothalamic stress response in infants of mothers who breastfed their infants versus infants of mothers who did not breastfeed.

METHODS

A cohort study of term, healthy infants and their mothers who did (n = 21) or did not (n = 21) breastfeed for the first 5 months was used in this analysis. Cortisol stress reactivity was measured in infant saliva by using a mother-infant interaction procedure and DNA methylation of an important regulatory region of the glucocorticoid receptor gene. Changes in DNA methylation of this gene in humans were compared to homologous regions of the rat gene. DNA samples were prepared from cheek swabs and subjected to quantitative analysis of the extent of methylation by using sensitive sequencing techniques.

RESULTS

Breastfeeding was associated with decreased DNA methylation of the glucocorticoid receptor promoter and decreased cortisol reactivity in 5-month-old infants. Decreased DNA methylation occurred in the promoter region involved in regulation of the hypothalamic-pituitary-adrenal and immune system responses.

CONCLUSIONS

Maternal care in humans may impact the hypothalamic-pituitary-adrenal stress response through behavioral programming and manifest as offspring epigenetic change. These results explain, in part, some of the positive effects observed in children who are breastfed.

Testing the programming of temperament and psychopathology in two independent samples of children with prenatal substance exposure

Prenatal programming models have rarely been applied to research on children with prenatal substance exposure, despite evidence suggesting that prenatal drug exposure is a form of stress that impacts neurodevelopmental outcomes and risk for psychopathology. Utilizing data from two longitudinal multisite studies comprising children prenatally exposed to substances as well as a nonexposed comparison group (Maternal Lifestyle Study, n = 1,388; Infant Development, Environment, and Lifestyle study, n = 412), we tested whether early phenotypic indicators of hypothesized programming effects, indexed by growth parameters at birth and infant temperament, served as a link between prenatal substance exposure and internalizing and externalizing behavior at age 5. Latent profile analysis indicated that individual differences in reactivity and regulation for infants prenatally exposed to substances was best characterized by four temperament profiles. These profiles were virtually identical across two independent samples, and demonstrated unique associations with adjustment difficulties nearly 5 years later. Results of path analysis using structural equation modeling also showed that increased prenatal substance exposure was linked to poorer growth parameters at birth, profiles of temperamental reactivity in infancy, and internalizing and externalizing behavior at age 5. This pathway was partially replicated across samples. This study was among the first to link known individual-level correlates of prenatal substance exposure into a specific pathway to childhood problem behavior. Implications for the developmental origins of a child's susceptibility to psychopathology as a result of intrauterine substance exposure are discussed.

Prenatal exposure to maternal depression and anxiety on imprinted gene expression in placenta and infant neurodevelopment and growth

BackgroundDepression and/or anxiety during pregnancy have been associated with impaired fetal growth and neurodevelopment. Because placental imprinted genes play a central role in fetal development and respond to environmental stressors, we hypothesized that imprinted gene expression would be affected by prenatal depression and anxiety.MethodsPlacental gene expression was compared between mothers with prenatal depression and/or anxiety/obsessive compulsive disorder/panic and control mothers without psychiatric history (n=458) in the Rhode Island Child Health Study.ResultsTwenty-nine genes were identified as being significantly differentially expressed between placentae from infants of mothers with both depression and anxiety (n=54), with depression (n=89), or who took perinatal psychiatric medications (n=29) and control mother/infant pairs, with most genes having decreased expression in the stressed group. Among placentae from infants of mothers with depression, we found no differences in expression by medication use, indicating that our results are related to the stressor rather than the treatments. We did not find any relationship between the stress-associated gene expression and neonatal neurodevelopment, as measured using the Neonatal Intensive Care Unit Network Neurobehavioral Scale.ConclusionsThis variation in expression may be part of an adaptive mechanism by which the placenta buffers the infant from the effects of maternal stress.

Epigenetic mechanisms in the placenta related to infant neurodevelopment

As the 'third brain' the placenta links the developing fetal brain and the maternal brain enabling study of epigenetic process in placental genes that affect infant neurodevelopment. We described the characteristics and findings of the 17 studies on epigenetic processes in placental genes and human infant neurobehavior. Studies showed consistent findings in the same cohort of term healthy infants across epigenetic processes (DNA methylation, genome wide, gene and miRNA expression) genomic region (single and multiple genes, imprinted genes and miRNAs) using candidate gene and genome wide approaches and across biobehavioral systems (neurobehavior, cry acoustics and neuroendocrine). Despite limitations, studies support future work on molecular processes in placental genes related to neurodevelopmental trajectories including implications for intervention.

Maternal and infant affect at 4 months predicts performance and verbal IQ at 4 and 7 years in a diverse population

Using existing longitudinal data from 570 infants in the Maternal Lifestyle Study, we explored the predictive value of maternal and infant affect and maternal vocalizations during 2 minutes of face-to-face interactions at 4 months on IQ scores at 4.5 and 7 years. After controlling for demographic factors, maternal depression, and prenatal drug exposure, maternal positive affect and maternal positive vocalizations emerged as predictors of both verbal and performance IQ at 4.5 and 7 years. Although infant positive affect during the interaction with the mother was not predictive of these outcome measures, infant positive affect towards an examiner predicted verbal but not performance IQ at 4.5 years. These results suggest that maternal positive affect may index emotional engagement in interaction that facilitates both verbal and nonverbal cognitive development, while infant social positive affect is specifically related to the acquisition of verbal reasoning abilities. These findings are significant because they are based on a discrete snapshot of observable behavior in infancy (just 2 minutes of interaction), because they extend the range of maternal behaviors and characteristics known to support positive developmental outcomes, and because they are derived from high-risk infants where prevention efforts may be beneficial. Potential mechanisms for these associations are discussed, as are the clinical implications for identifying dyads most in need of targeted interventions.

Infants' early visual attention and social engagement as developmental precursors to joint attention

This study examined infants' early visual attention (at 1 month of age) and social engagement (4 months) as predictors of their later joint attention (12 and 18 months). The sample (n = 325), drawn from the Maternal Lifestyle Study, a longitudinal multicenter project conducted at 4 centers of the National Institute of Child Health and Human Development Neonatal Research Network, included high-risk (cocaine-exposed) and matched noncocaine-exposed infants. Hierarchical regressions revealed that infants' attention orienting at 1 month significantly predicted more frequent initiating joint attention at 12 (but not 18) months of age. Social engagement at 4 months predicted initiating joint attention at 18 months. Results provide the first empirical evidence for the role of visual attention and social engagement behaviors as developmental precursors for later joint attention outcome. (PsycINFO Database Record

Global motion perception is related to motor function in 4.5-year-old children born at risk of abnormal development

Global motion perception is often used as an index of dorsal visual stream function in neurodevelopmental studies. However, the relationship between global motion perception and visuomotor control, a primary function of the dorsal stream, is unclear. We measured global motion perception (motion coherence threshold; MCT) and performance on standardized measures of motor function in 606 4.5-year-old children born at risk of abnormal neurodevelopment. Visual acuity, stereoacuity and verbal IQ were also assessed. After adjustment for verbal IQ or both visual acuity and stereoacuity, MCT was modestly, but significantly, associated with all components of motor function with the exception of fine motor scores. In a separate analysis, stereoacuity, but not visual acuity, was significantly associated with both gross and fine motor scores. These results indicate that the development of motion perception and stereoacuity are associated with motor function in pre-school children.

Epigenetic Regulation of Placental NR3C1: Mechanism Underlying Prenatal Programming of Infant Neurobehavior by Maternal Smoking?

Epigenetic regulation of the placental glucocorticoid receptor gene (NR3C1) was investigated as a mechanism underlying links between maternal smoking during pregnancy (MSDP) and infant neurobehavior in 45 mother-infant pairs (49% MSDP-exposed; 52% minorities; ages 18-35). The Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scale was administered 7 times over the 1st postnatal month; methylation of placental NR3C1 was assessed via bisulfite pyrosequencing. Increased placental NR3C1 methylation was associated with increased infant attention and self-regulation, and decreased lethargy and need for examiner soothing over the 1st postnatal month. A causal steps approach revealed that NR3C1 methylation and MSDP were independently associated with lethargic behavior. Although preliminary, results highlight the importance of epigenetic mechanisms in elucidating pathways to neurobehavioral alterations from MSDP.

The Contributions of Maternal Sensitivity and Maternal Depressive Symptoms to Epigenetic Processes and Neuroendocrine Functioning

This study tested whether maternal responsiveness may buffer the child to the effects of maternal depressive symptoms on DNA methylation of NR3C1, 11β-HSD2, and neuroendocrine functioning. DNA was derived from buccal epithelial cells and prestress cortisol was obtained from the saliva of 128 infants. Mothers with depressive symptoms who were more responsive and who engaged in more appropriate touch during face-to-face play had infants with less DNA methylation of NR3C1 and 11β-HSD2 compared to mothers with depressive symptoms who were also insensitive. The combination of exposure to maternal depressive symptoms and maternal sensitivity was related to the highest prestress cortisol levels, whereas exposure to maternal depressive symptoms and maternal insensitivity was related to the lowest prestress cortisol levels.