Glucocorticoid exposure in preterm babies predicts saliva cortisol response to immunization at 4 months

Exposure to antenatal corticosteroids and infant cortisol regulation

Administration of antenatal corticosteroids (AC) is the standard of care during pregnancy for women who are at risk of early delivery. Evidence indicates that AC improve survival and reduce morbidity for preterm infants. However, research suggests that infants whose mothers receive AC have an altered hypothalamic-pituitary-axis (HPA) response to stressors in early life. Results are mixed regarding the nature of these effects, with studies showing both suppressed and augmented HPA activity. In addition, research is very limited beyond the 4th month of life. The purpose of this study was to determine if AC exposure was associated with infant cortisol levels in a resting state or in response to a stressor at 1, 6 and 12 months postnatal. We also evaluated the moderating role of preterm birth in this association. 181 women and their infants participated in the study. Women were recruited during the 3rd trimester of pregnancy; at this time, they completed the Perceived Stress Scale and provided 8 salivary samples over a 2-day period for cortisol assay. They provided these data again at 6 and 12 months postnatal. At 1, 6, and 12 months postnatal, salivary samples were collected from infants to examine their cortisol levels before and after participation in a 'stressor protocol'. Data were extracted from the medical record on AC exposure, gestational age, maternal obstetric risk, and neonatal morbidity. Mixed effects multilevel regression modeling was used to examine the aims. Infants whose mothers received AC had significantly lower resting state (B = -2.47, CI: -3.691, -0.0484) and post-stressor (B = -2.51, CI: -4.283, -0.4276) cortisol levels across the first year of life than infants whose mothers did not receive AC. There was no moderating effect of preterm birth on the relationship between AC exposure and cortisol. Results indicate a state of dampened HPA activation and cortisol hypo-arousal that persists across the first year of life among infants who were exposed to corticosteroids in utero. Further research is needed to examine mechanisms responsible for any alterations that occur during development of the fetal HPA axis, including epigenetic and biochemical factors that control hormonal secretion, negative feedback, and glucocorticoid receptor function throughout the HPA axis. Findings warrant careful consideration by obstetric clinicians of the benefits and risks of prescribing AC.

Developmental Programming by Perinatal Glucocorticoids

Early-life environmental factors can have persistent effects on physiological functions by altering developmental procedures in various organisms. Recent experimental and epidemiological studies now further support the idea that developmental programming is also present in mammals, including humans, influencing long-term health. Although the mechanism of programming is still largely under investigation, the role of endocrine glucocorticoids in developmental programming is gaining interest. Studies found that perinatal glucocorticoids have a persistent effect on multiple functions of the body, including metabolic, behavioral, and immune functions, in adulthood. Several mechanisms have been proposed to play a role in long-term programming. In this review, recent findings on this topic are summarized and the potential biological rationale behind this phenomenon is discussed.

Saliva cortisol diurnal variation and stress responses in term and preterm infants

OBJECTIVE

To determine if preterm birth is associated with adaptation of the hypothalamic-pituitary-adrenal (HPA) axis and whether HPA axis programming relates to the degree of prematurity (defined as extremely preterm birth at <28 weeks or very preterm birth at 28-32 weeks gestation).

DESIGN

This study reports findings from a prospective birth cohort. Saliva cortisol concentrations were measured prevaccination and postvaccination, and in the morning and evening, at 4 months chronological age.

SETTING

Infants born at a single Scottish hospital.

PARTICIPANTS

45 term-born, 42 very preterm and 16 extremely preterm infants.

OUTCOMES

Cortisol stress response to vaccination (postvaccination minus prevaccination cortisol concentrations), diurnal slope (log-transformed morning minus log-transformed evening cortisol values) and mean log-transformed daily cortisol.

RESULTS

Compared with infants born at term, infants born extremely preterm had a blunted cortisol response to vaccination (5.8 nmol/L vs 13.1 nmol/L, difference in means: -7.3 nmol/L, 95% CI -14.0 to -0.6) and a flattened diurnal slope (difference in geometric means: -72.9%, 95% CI -87.1 to -42.8). In contrast, the cortisol response to vaccination (difference in means -2.7 nmol/L, 95% CI -7.4 to 2.0) and diurnal slope at 4 months (difference in geometric means: -33.6%, 95% CI -62.0 to 16.0) did not differ significantly in infants born very preterm compared with infants born at term.

CONCLUSIONS

Infants born extremely preterm have blunted cortisol reactivity and a flattened diurnal slope. These patterns of HPA axis regulation are commonly seen after childhood adversity and could contribute to later metabolic and neurodevelopmental phenotypes observed in this population.

Perinatal determinants of neonatal hair glucocorticoid concentrations

Adult hair glucocorticoid concentrations reflect months of hypothalamic-pituitary-adrenal axis activity. However, little is known about the determinants of neonatal hair glucocorticoids. We tested associations between perinatal exposures and neonatal hair glucocorticoids. Cortisol and cortisone were measured by LC-MS/MS in paired maternal and infant hair samples collected within 10 days of birth (n = 49 term, n = 47 preterm), with neonatal samples collected at 6-weeks in n = 54 preterm infants. We demonstrate cortisol accumulation in hair increases with fetal maturity, with hair cortisol being higher in term than preterm born infants after delivery (median 401 vs 106 pg/mg; p < 0.001). In term born infants, neonatal hair cortisol is positively associated with maternal hair cortisol concentration (β = 0.240, p = 0.045) and negatively associated with birthweight z-score (β = -0.340, p = 0.006). Additionally, being born without maternal labour is associated with lower hair cortisol concentrations (β = -0.489, p < 0.001) and a lower ratio of cortisol to cortisone (β = -0.484, p = 0.001). In preterm infants, histological chorioamnionitis is associated with a higher cortisol to cortisone ratio in hair (β = 0.459, p = 0.001). In samples collected 6 weeks after preterm birth, hair cortisol concentration is associated with cortisol hair concentrations measured after birth (β = 0.523, p < 0.001), chorioamnionitis (β = 0.250, p = 0.049) and postnatal exposures including intravenous hydrocortisone therapy (β = 0.343, p < 0.007) and neonatal sepsis (β = 0.290, p = 0.017). In summary, neonatal hair cortisol is associated with birth gestation, maternal hair cortisol concentration and fetal growth. Additionally, exposures at delivery are important determinants of hair cortisol, and should be considered in the design of future research investigating how neonatal hair cortisol relates to prenatal exposures or fetal development.

The development of the hypothalamus-pituitary-adrenal axis during infancy may be affected by antenatal glucocorticoid therapy

BACKGROUND

Developmental changes in the hypothalamus-pituitary-adrenal (HPA) axis during infancy have been reported in term infants, but those in preterm infants have yet to be elucidated. If developmental changes in the HPA axis of preterm infants are modulated by any factors, it may affect their future health. Few studies have examined the lasting consequences of antenatal glucocorticoids on the development of the HPA axis.

METHODS

We measured pre- and post-palivizumab vaccination salivary cortisol values in two conforming periods of three-months intervals during infancy, and compared cortisol values and the response of cortisol secretion between groups with and without antenatal glucocorticoid (AG) therapy.

RESULTS

Although the strength of the response of cortisol secretion to palivizumab fell age-dependently (until late infancy) in the Non-AG group, the opposite pattern was exhibited in the AG group. The changes of the delta cortisol values between the 2 groups were significant.

CONCLUSIONS

This study suggests that the HPA axis of preterm infants whose mothers receive AG therapy may be upregulated during infancy, possibly leading to long lasting health problems.

Hypothalamic-pituitary-adrenal axis and autonomic nervous system reactivity in children prenatally exposed to maternal depression: A systematic review of prospective studies

Depression is a common condition affecting up to 20% of all pregnant women, and is associated with subsequent developmental and behavioral problems in children, such as conduct disorder and ADHD. One proposed mechanism underlying these associations is modification of the fetal hypothalamic pituitary adrenal (HPA)-axis and the autonomic nervous system (ANS), resulting in altered responses to stress. This review examined the evidence regarding altered HPA-axis and ANS reactivity in children prenatally exposed to high maternal depressive symptoms. A systematic search was conducted in the electronic databases MEDLINE, EMBASE and PsycINFO, for studies published till 25 July 2017. A total of 13 studies comprising 2271 mother-infant dyads were included. None of the studies were suitable for meta-analysis. Risk of bias assessment showed low risk for four studies. Only three studies described an independent association between exposure to high maternal prenatal depressive symptoms and altered stress reactivity in children. There is limited evidence of an independent association between prenatal exposure to maternal depression and altered HPA or ANS reactivity in children.

Prenatal bisphenol a exposure and dysregulation of infant hypothalamic-pituitary-adrenal axis function: findings from the APrON cohort study

BACKGROUND

Animal models show that prenatal bisphenol A (BPA) exposure leads to sexually dimorphic disruption of the neuroendocrine system in offspring, including the hypothalamic-pituitary-adrenal (HPA) neuroendocrine system, but human data are lacking. In humans, prenatal BPA exposure is associated with sex-specific behavioural problems in children, and HPA axis dysregulation may be a biological mechanism. The objective of the current study was to examine sex differences in associations between prenatal maternal urinary BPA concentration and HPA axis function in 3 month old infants.

METHODS

Mother-infant pairs (n = 132) were part of the Alberta Pregnancy Outcomes and Nutrition study, a longitudinal birth cohort recruited (2010-2012) during pregnancy. Maternal spot urine samples collected during the 2nd trimester were analyzed for total BPA and creatinine. Infant saliva samples collected prior to and after a blood draw were analyzed for cortisol. Linear growth curve models were used to characterize changes in infant cortisol as a function of prenatal BPA exposure.

RESULTS

Higher maternal BPA was associated with increases in baseline cortisol among females (β = 0.13 log μg/dL; 95% CI: 0.01, 0.26), but decreases among males (β = -0.22 log μg/dL; 95% CI: -0.39, -0.05). In contrast, higher BPA was associated with increased reactivity in males (β = .30 log μg/dL; 95% CI: 0.04, 0.56) but decreased reactivity in females (β = -0.15 log μg/dL; 95% CI: -0.35, 0.05). Models adjusting for creatinine yielded similar results.

CONCLUSIONS

Prenatal BPA exposure is associated with sex-specific changes in infant HPA axis function. The biological plausibility of these findings is supported by their consistency with evidence in rodent models. Furthermore, these data support the hypotheses that sexually dimorphic changes in children's behaviour following prenatal BPA exposure are mediated by sexually dimorphic changes in HPA axis function.

Sexually dimorphic and interactive effects of prenatal maternal cortisol and psychological distress on infant cortisol reactivity

In utero exposure to maternal psychological distress is a risk factor for developmental psychopathology, and these effects are believed to partially occur via dysregulation of the maternal and fetal hypothalamus-adrenal-pituitary axes. Nevertheless, only a few human studies have directly assessed the effects of prenatal cortisol exposure on infant cortisol reactivity, and none have investigated sex differences or potential interactions between prenatal cortisol and psychological distress. Here we report on a prospective longitudinal investigation (N = 236) of in utero exposure to maternal cortisol and distress in a relatively high socioeconomic status and low-risk population to determine whether these exposures interact in their effects on infant (M age = 3.0 months, range = 2.3-5.0 months, 51.9% male) cortisol reactivity and whether there are sex differences in these effects. Results revealed both sexually dimorphic and interactive effects of prenatal cortisol and distress, even after controlling for postnatal distress. In general, blunted reactivity in females was associated with exposure to high maternal distress and flattened patterns of diurnal maternal cortisol, whereas blunted reactivity in males was associated with exposure to steeper morning increases and daytime decreases in maternal cortisol. The findings suggest that sex differences in the effects of prenatal cortisol and distress on infant cortisol reactivity are a plausible mechanism by which maternal experiences during pregnancy contribute to sex differences in the development of psychopathology.

Development of Cardiovascular Indices of Acute Pain Responding in Infants: A Systematic Review

Background. Cardiovascular indices of pain are pervasive in the hospital setting. However, no prospective research has examined the development of cardiac responses to acutely painful procedures in the first year of life. Objectives. Our main goal was to synthesize existing evidence regarding the development of cardiovascular responses to acutely painful medical procedures over the first year of life in preterm and term born infants. Methods. A systematic search retrieved 6994 articles to review against inclusion criteria. A total of 41 studies were included in the review. Results. In response to acutely painful procedures, most infants had an increase in mean heart rate (HR) that varied in magnitude both across and within gestational and postnatal ages. Research in the area of HR variability has been inconsistent, limiting conclusions. Conclusions. Longitudinal research is needed to further understand the inherent variability of cardiovascular pain responses across and within gestational and postnatal ages and the causes for the variability.

Differential Gene Expression in Liver, Gill, and Olfactory Rosettes of Coho Salmon (Oncorhynchus kisutch) After Acclimation to Salinity

Most Pacific salmonids undergo smoltification and transition from freshwater to saltwater, making various adjustments in metabolism, catabolism, osmotic, and ion regulation. The molecular mechanisms underlying this transition are largely unknown. In the present study, we acclimated coho salmon (Oncorhynchus kisutch) to four different salinities and assessed gene expression through microarray analysis of gills, liver, and olfactory rosettes. Gills are involved in osmotic regulation, liver plays a role in energetics, and olfactory rosettes are involved in behavior. Between all salinity treatments, liver had the highest number of differentially expressed genes at 1616, gills had 1074, and olfactory rosettes had 924, using a 1.5-fold cutoff and a false discovery rate of 0.5. Higher responsiveness of liver to metabolic changes after salinity acclimation to provide energy for other osmoregulatory tissues such as the gills may explain the differences in number of differentially expressed genes. Differentially expressed genes were tissue- and salinity-dependent. There were no known genes differentially expressed that were common to all salinity treatments and all tissues. Gene ontology term analysis revealed biological processes, molecular functions, and cellular components that were significantly affected by salinity, a majority of which were tissue-dependent. For liver, oxygen binding and transport terms were highlighted. For gills, muscle, and cytoskeleton-related terms predominated and for olfactory rosettes, immune response-related genes were accentuated. Interaction networks were examined in combination with GO terms and determined similarities between tissues for potential osmosensors, signal transduction cascades, and transcription factors.

Tailored Assays for Pharmacokinetic and Pharmacodynamic Investigations of Aliskiren and Enalapril in Children: An Application in Serum, Urine, and Saliva

OBJECTIVES

Drugs that are effectively used to treat hypertension in adults (e.g., enalapril) have not been sufficiently investigated in children. Studies required for pediatric approval require special consideration regarding ethics, study design, and conduct and are also associated with special demands for the bioanalytic method. Pediatric-appropriate assays can overcome these burdens and enable systematic investigations of pharmacokinetics and pharmacodynamic in all pediatric age groups.

METHODS

Tailored assays were developed for pharmacokinetic investigation of a drug in 100 μL of serum, saliva, and urine. All assays were applied in a proof-of-concept study to 22 healthy volunteers who had been given 300 mg aliskiren hemifumarate or 20 mg enalapril maleate and allowed for dense sampling. Changes in humoral parameters of the renin-angiotensin-aldosterone system were also evaluated with 6 parameters in 2.1 mL blood per time point.

RESULTS

The pharmacokinetic results of aliskiren and enalapril obtained by low-volume assays in serum and urine were comparable to that noted in the literature. The dense sampling enabled very detailed concentration-time profiles that showed high intersubject variability and biphasic absorption behavior of aliskiren. The replacement of invasive sampling by saliva collection appears inappropriate for both drugs because the correlations of drug concentrations in both fluids were low. A low-volume assay was also used to determine values for in the renin-angiotensin-aldosterone system and to compare those results with the published literature.

CONCLUSION

These results support both the use of low-volume assays in pediatric research and the systematic investigation of their use in neonates and infants. Use of this assay methodology will increase information about drug pharmacokinetics and pharmacodynamics in this vulnerable population and might contribute to safe and effective use of pharmacotherapy.

Foetal exposure to maternal depression predicts cortisol responses in infants: findings from rural South India

BACKGROUND

Maternal depression during pregnancy is associated with an increased risk of adverse child outcomes. One potential mechanism is the influence of antenatal depression on the foetal hypothalamic-pituitary-adrenal axis. This can be observed as disturbances in baseline cortisol secretion during childhood. The influence of antenatal depression on infant cortisol reactivity to a stressor may provide further insight into this association. In addition, the dose-response relationship between foetal exposure to antenatal depression and infant cortisol reactivity is unclear.

METHODS

A consecutive sample of 133 pregnant women in their third trimester was recruited from an antenatal clinic in Karnataka, South India. Women were assessed for depression before and after birth on the Edinburgh Postnatal Depression Scale (EPDS) and the Kessler 10 Scale. Salivary cortisol response to immunization was measured in 58 infants at 2 months of age. We aimed (i) to investigate the association between antenatal depression and infant cortisol reactivity to immunization and (ii) to explore whether the relationship is dose-dependent.

RESULTS

Exposure to antenatal depression independently predicted elevated infant cortisol responses to immunization (β = 0.53, P = 0.04). The association was found to be U-shaped, for antenatal depression measured on the EPDS, with the infants exposed to the highest and lowest levels of maternal antenatal EPDS scores during intra-uterine life showing elevated cortisol responses to immunization (R(2) = 0.20, P = 0.02). Infants exposed to moderate levels of maternal antenatal depression showed the lowest cortisol response to immunization.

CONCLUSIONS

These findings suggest that the association between antenatal depression and infant cortisol reactivity is dose-dependent and U-shaped, implying that infants exposed to both low and high levels of maternal depression showed greater reactivity. The study provides the first evidence of such an association from a low-income setting.

Effects of Antenatal Corticosteroids on Cortisol and Heart Rate Reactivity of Preterm Infants

Administration of glucocorticoids (GCs) during pregnancy is an established practice for reducing morbidity and mortality of fetuses at risk of preterm delivery. However, preliminary research indicates that exposure to exogenous GCs in utero may be associated with suppressed hypothalamic–pituitary–adrenal axis activity. The aim of this study was to determine whether preterm neonates who are exposed to antenatal corticosteroids show evidence of a suppressed stress-response system during their first few weeks of life, in contrast to infants who are not exposed. The sample (51% female) included 57 neonates, with 74% exposed to steroids. Mean gestational ages (GAs) were 32.6 weeks for exposed and 34.7 weeks for nonexposed infants. Although neonates in the two groups differed in gender, birth weight, and morbidity, these factors were controlled for in data analyses. Infants’ salivary cortisol and heart rate (HR) were measured before and after they received a standardized caregiving “stressor” while in the newborn intensive care unit. Infants exposed to GCs in utero had lower basal cortisol levels and higher HRs than their nonexposed peers. In contrast to infants who received no GCs, they also exhibited minimal HR or cortisol reactivity to the stressor. Findings suggest that preterm infants who were exposed to antenatal corticosteroids experience a suppressed response to stress. As preterm children develop, this dysregulation has numerous implications for later development of stress-related cardiovascular and mental health problems. Further research is needed to determine whether these postnatal effects of antenatal corticosteroids persist over time.

Prematurity and programming of cardiovascular disease risk: a future challenge for public health?

There is substantial epidemiological evidence linking low birth weight with adult cardiometabolic disease risk factors. This has led to the concept of 'early life programming' or the 'developmental origins of disease' which proposes that exposure to adverse conditions during critical stages of early development results in compensatory mechanisms predicted to aid survival. There is growing evidence that preterm infants, many of whom are of low birth weight, are also at increased risk of adult cardiometabolic disease. In this article, we provide a broad overview of the evidence linking preterm birth and cardiovascular disease risk and discuss potential consequences for public health.

The effects of kangaroo mother care in a sample of preterm, preschool aged children

<b>Background</b><br /> The research has shown that kangaroo mother care has a protective impact both on health and future cognitive skills of prematurely born babies. The aim of this study was to investigate the relation between the early skin-to-skin contact and the cognitive and emotional-social functioning of preschool aged preterm babies.<br /> <br /> <b>Participants and procedure</b><br /> The study group included 99 preterm babies. The children participated in a psychological examination conducted using the Columbia Mental Maturity Scale and the Terman-Merrill Test. The data concerning the skin-to-skin contact during the child’s hospitalisation were acquired during interviews with mothers. The emotional development was assessed on the basis of interviews with mothers, conducted using the Rescorla DSM-IV Orientation Scale (2005).<br /> <br /> <b>Results</b><br /> The study showed no relation between kangaroo mother care and cognitive development. Nevertheless the early skin-to-skin contact turned out to be connected with the emotional functioning of the subjects. Preterm babies who used to experience kangaroo mother care experienced fewer anxiety and depressive disorders than those who did not. In addition it was revealed that the children who suffered from early damage to the brain in the forms of intraventricular and periventricular haemorrhages and experienced kangaroo mother care demonstrated less intense depressive symptoms than those who did not.<br /> <br /> <b>Conclusions</b><br /> The obtained results, combined with the review of the foreign literature of the subject, indicate the usefulness of introducing kangaroo mother care to neonatal wards and encouraging parents to care about their prematurely born babies in such a way.

Prenatal and postnatal inflammation in relation to cortisol levels in preterm infants at 18 months corrected age

OBJECTIVE

To examine whether early inflammation is related to cortisol levels at 18 months corrected age (CA) in children born very preterm.

STUDY DESIGN

Infants born ≤ 32 weeks of gestational age were recruited in the neonatal intensive care unit (NICU), and placental histopathology, magnetic resonance imaging (MRI) and chart review were obtained. At 18 months CA, developmental assessment and collection of three salivary cortisol samples were carried out. Generalized least squares was used to analyze data from 85 infants providing 222 cortisol samples.

RESULT

Infants exposed to chorioamnionitis with funisitis had a significantly different pattern of cortisol across the samples compared with infants with chorioamnionitis alone or no prenatal inflammation (F(4, 139)=7.3996, P<0.0001). Postnatal infections, necrotizing enterocolitis and chronic lung disease were not significantly associated with the cortisol pattern at 18 months CA.

CONCLUSION

In children born very preterm, prenatal inflammatory stress may contribute to altered programming of the hypothalamic-pituitary-adrenal (HPA) axis.

Effects of early- and late-gestational maternal stress and synthetic glucocorticoid on development of the fetal hypothalamus-pituitary-adrenal axis in sheep

Prenatal maternal stress (PMS) programs dysregulation of the hypothalamus-pituitary-adrenal axis (HPAA) in postnatal life, though time periods vulnerable to PMS, are still unclear. We evaluated in pregnant sheep the effect of PMS during early gestation [30-100 days of gestation (dGA); term is 150 dGA] or late gestation (100-120 dGA) on development of fetal HPAA function. We compared the effects of endogenous cortisol with synthetic glucocorticoid (GC) exposure, as used clinically to enhance fetal lung maturation. Pregnant sheep were exposed to repeated isolation stress twice per week for 3 h in a separate box with no visual, tactile, or auditory contact with their flock-mates either during early (n = 7) or late (n = 7) gestation. Additional groups received two courses of betamethasone (BM; n = 7; 2 × 110 μg kg(- 1) body weight, 24 h apart) during late gestation (106/107 and 112/113 dGA, n = 7) or acted as controls (n = 7). Fetal cortisol responses to hypotensive challenge, a physiological fetal stressor, were measured at 112 and 129 dGA, i.e. before and during maturation of the HPAA. Hypotension was induced by fetal infusion of sodium nitroprusside, a potent vasodilator. At 112 dGA, neither PMS nor BM altered fetal cortisol responses. PMS, during early or late gestation, and BM treatment increased fetal cortisol responses at 129 dGA with the greatest increase achieved in stressed early pregnant sheep. Thus, development of the HPAA is vulnerable to inappropriate levels of GCs during long periods of fetal life, whereas early gestation is most vulnerable to PMS.

Effects of antenatal corticosteroids on the hypothalamic-pituitary-adrenocortical axis of the fetus and newborn: experimental findings and clinical considerations

The hypothalamic-pituitary-adrenocortical (HPA) axis is a major neuroendocrine pathway that modulates the stress response. The glucocorticoid, cortisol, is the principal end product of the HPA axis in humans and plays a fundamental role in maintaining homeostasis and in fetal maturation and development. Antenatal administration of synthetic glucocorticoids (GCs) accelerates fetal lung maturation and has significantly decreased neonatal mortality and morbidity in infants born before 34 weeks of gestation. Exposure to excess levels of endogenous GCs and exogenous GCs (betamethasone and dexamethasone) has been shown to alter the normal development trajectory. The development and regulation of the fetal HPA axis is discussed and the experimental animal evidence presented suggests long-term adverse consequences of altered HPA function. The clinical data in infants exposed to GCs also suggest altered HPA axis function over the short term. The longer-term consequences of antenatal GC exposure on HPA axis function and subtler neurodevelopmental outcomes including adaptation to stress, cognition, behavior, and the cardiovascular and immune responses are poorly understood. Emerging clinical strategies and interventions may help in the selection of mothers at risk for preterm delivery who would benefit from existing or future formulations of antenatal GCs with a reduction in the associated risk to the fetus and newborn. Detailed longitudinal long-term follow-up of those infants exposed to synthetic GCs are needed.

The Stockholm Neonatal Family-Centered Care Study: effects on salivary cortisol in infants and their mothers

BACKGROUND

Parental involvement in the care of preterm infants in neonatal intensive care units (NICUs) is common, but little is known about the effect on stress responses in mothers and infants.

AIMS

The aim of this study is to evaluate the effect of family-centered care on salivary cortisol reactivity in mothers and preterm infants and the correlation between the mothers' and the preterm infants' salivary cortisol levels.

METHODS

This study is part of a randomized controlled trial conducted at two level-II NICUs, including Family Care (FC), where parents were able to stay 24h/day from admission to discharge, and Standard Care (SC). To investigate the cortisol response, saliva was collected from 289 preterm infants and their mothers before and after a diaper change at the time of discharge.

RESULTS

No significant differences were found between the two groups in salivary cortisol reactivity, either in mothers or in infants. The results revealed a correlation between preterm infants' and their mothers' baseline and response cortisol in the FC group: r=0.31 (p=0.001) and r=0.24 (p=0.01), respectively. Such correlation was not observed in the SC group: r=0.14 (p=0.14) and r=0.18 (p=0.07), respectively.

CONCLUSIONS

Family-centered care had no effect on salivary cortisol reactivity during diaper change. However, sharing the same environment may increase the concordance between preterm infants' and their mothers' salivary cortisol levels.

Single course of antenatal steroids did not alter cortisol in preterm infants up to 18 months

AIMS

To determine whether a single course of antenatal dexamethasone alters resting cortisol at 3, 8 and 18 months corrected age in preterm infants.

METHODS

Preterm infants born ≤32 weeks gestational age were recruited during 2001-2004 from a single neonatal intensive care unit. Resting salivary cortisol was collected at least once at 3, 8 and 18 months corrected age in a longitudinal cohort. A mixed-effects repeated measures analysis was used to accommodate cases with less than complete follow-up.

RESULTS

One hundred and thirty three infants were included in the present study, contributing 266 cortisol samples. Of these, 107 infants had been exposed to a single course of antenatal dexamethasone and 26 not exposed to antenatal steroids. There was no significant main effect of antenatal steroids on resting cortisol at any age. This result was not altered after adjusting for gestational age at birth, neonatal cumulative pain, morphine exposure, mechanical ventilation days and post-natal steroid exposure.

CONCLUSIONS

No effect of a single course of dexamethasone on resting salivary cortisol, an indicator of hypothalamic-pituitary-adrenal axis function, was found in infancy up to 18 months corrected age in infants born very preterm.

Psychobiological effects of prenatal glucocorticoid exposure in 10-year-old-children

BACKGROUND

Prenatal stress seems to have long-lasting effects on biological and psychological processes of the offspring. However, to date, there have been no studies investigating the effects of prenatal glucocorticoid exposure on psychological, endocrine, and autonomic responses to a standardized psychosocial stress test in children.

METHODS

A sample of 115 healthy, 10-year-old children was examined. The Glucocorticoids + Tocolytics group was characterized by tocolytic treatment of the mothers due to preterm labor (n = 43). In addition, the pregnant women received glucocorticoid treatment in order to accelerate fetal lung maturation in case of preterm birth. The first comparison group (Tocolytics) consisted of children whose mothers also experienced preterm labor, but did not receive glucocorticoid treatment (n = 35). In the second comparison group (CONTROL), children whose mothers had a complication-free pregnancy were assessed (n = 37). Psychological parameters (stress appraisal and mood) using self-report questionnaires as well as salivary cortisol, salivary alpha-amylase, and heart rate were measured during a standardized psychosocial stress test (Trier Social Stress Test for Children).

RESULTS

Group comparisons revealed that a subscale of stress appraisal, control expectancies, significantly differed in children who were prenatally exposed to glucocorticoids as compared to both comparison groups (F = 4.889, p = 0.009). Furthermore, significant differences between the groups were revealed for salivary cortisol. With respect to overall stress appraisal and heart rate, trends toward significance were observed between the three groups.

CONCLUSION

At the age of ten, those children who have been exposed to prenatal maternal glucocorticoids show changed psychobiological stress reactivity to a standardized psychosocial stress test as compared to control children.

Mechanical-tactile stimulation (MTS) during neonatal stress prevents hyperinsulinemia despite stress-induced adiposity in weanling rat pups

Stress in early life negatively influences growth quality through perturbations in body composition including increased fat mass. At term (40 weeks) preterm infants have greater fat mass and abdominal visceral adipose tissue than term-born infants. Mechanical-tactile stimulation (MTS) attenuates the stress response in preterm infants and rodents. We tested the hypothesis that MTS, administered during an established model of neonatal stress, would decrease stress-driven adiposity and prevent associated metabolic imbalances in rat pups. Pups received one of three treatments from postnatal days 5 to P9: Neonatal Stress (Stress; n=20) = painful stimulus and hypoxic/hyperoxic challenge during 60 min of maternal separation; MTS (n=20) = neonatal stress+10 min of MTS; or Control (n=20). Body weight, DXA whole body fat mass (g), MRI subcutaneous and visceral adipose tissue, and fasting adiponectin, leptin, glucose, insulin, and corticosterone were measured at weaning (P21). Stress and MTS weight gain (g/d) were accelerated following neonatal stress with greater fat mass, abdominal subcutaneous adipose tissue, serum adiponectin, leptin, and fasting glucose at weaning (P21). Male Stress and MTS pups had greater visceral adipose tissue depot. Male and female Stress pups were hyperinsulinemic. In summary, neonatal stress compromised body composition by increasing fat mass and abdominal subcutaneous adipose tissue depot, and in males, visceral adipose tissue depot. Importantly, MTS prevented hyperinsulinemia despite of stress-induced adiposity. We conclude that MTS during neonatal stress has the potential to minimize metabolic consequences associated with stress-driven perturbations in fat mass and abdominal adipose depots.

Cortisol, behavior, and heart rate reactivity to immunization pain at 4 months corrected age in infants born very preterm

OBJECTIVE

Pain response may be altered in infants born very preterm owing to repeated exposure to procedures in the neonatal intensive care unit. Findings have been inconsistent in studies of behavioral and cardiac responses to brief pain in preterm versus full-term infants following neonatal intensive care unit discharge. To our knowledge, cortisol reactivity to pain has not been compared in preterm and full-term infants. We examined pain reactivity to immunization in preterm and full-term infants.

METHOD

Cortisol, facial behavior, and heart rate reactivity before, during, and after immunization were examined in infants born preterm at extremely low gestational age (ELGA 24 to 28 wk), very low gestational age (VLGA 29 to 32 wk), and full-term, at corrected age 4 months.

RESULTS

In all groups, cortisol, behavior, and heart rate increased during immunizations. Cortisol concentrations were lower in preterm ELGA and VLGA boys, compared with full-term boys. In contrast, facial and heart rate responses to immunization did not differ between preterm and full-term infants.

DISCUSSION

Although earlier reports found differences in pain processing in preterm infants earlier and later in development, the present findings indicate that pain responses, indexed by behavior and heart-rate, do not seem to differ in preterm compared with full-term infants at 4 months corrected age. Importantly, however, stress regulation seems altered in preterm male infants. As cortisol impacts development and functioning of the brain, altered stress regulation has important implications beyond pain systems.

Effects of intrauterine exposure to synthetic glucocorticoids on fetal, newborn, and infant hypothalamic-pituitary-adrenal axis function in humans: a systematic review

BACKGROUND

Synthetic glucocorticoids are commonly used in reproductive medicine. Fetal organ systems are highly sensitive to changes in the intrauterine environment, including overexposure to glucocorticoids. Structural and functional alterations resulting from such changes may persist throughout life and have been associated with diverse diseases. One system that could be particularly sensitive to fetal glucocorticoid overexposure is the hypothalamic-pituitary-adrenal (hpa) axis. Many human studies have investigated this possibility, but a systematic review to identify consistent, emergent findings is lacking.

METHODS

We systematically review 49 human studies, assessing the effects of intrauterine exposure to synthetic glucocorticoids on fetal, neonate, and infant hpa function.

RESULTS

Study quality varied considerably, but the main findings held true after restricting the analyses to higher-quality studies: intrauterine exposure to synthetic glucocorticoids reduces offspring hpa activity under unstimulated conditions after pain but not pharmacological challenge. Although reduced unstimulated hpa function appears to recover within the first 2 wk postpartum, blunted hpa reactivity to pain is likely to persist throughout the first 4 months of life. There is some evidence that the magnitude of the effects is correlated with the total amount of glucocorticoids administered and varies with the time interval between glucocorticoid exposure and hpa assessment.

CONCLUSIONS

This systematic review has allowed the demonstration of the way in which intrauterine exposure to various regimens of synthetic glucocorticoids affects various forms of hpa function. As such, it guides future studies in terms of which variables need to be focused on in order to further strengthen the understanding of such therapy, whilst continuing to profit from its clinical benefits.

Prenatal stress and the programming of the HPA axis

There are several independent prospective studies showing that a wide variety of forms of prenatal stress can have long-term effects on the behavioural and cognitive outcome for the child. Animal studies have shown that prenatal stress, as well as affecting behaviour, can also reprogram the function of the HPA axis in the offspring. However, the effects on the HPA axis are very variable depending on the nature of the stress, its timing in gestation, the genetic strain of the animal, the sex and age of the offspring and whether basal or stimulated HPA axis responses are studied. There are also several recent studies showing long-term effects of prenatal stress on basal cortisol levels, or cortisol responses to stress, in humans. The designs of these studies differ considerably, many are small, and the effects on outcome are also varied. There is little evidence, so far, that altered function of the HPA axis in the child mediates the behavioural or cognitive alterations observed to be associated with prenatal stress.

Behavioral stress is affected by the mode of tube feeding in very low birth weight infants

OBJECTIVE

To compare the effect of continuous versus bolus feeding on behavioral responses of stress in very low birth weight infants during early postnatal life.

METHODS

In a randomized, controlled trial conducted at 3 neonatal units, 70 premature infants with gestational age 24 to 29 weeks and birth weight <1200 g were randomly assigned to 1 of 3 feeding methods: continuous nasogastric feeding, bolus nasogastric feeding, and bolus orogastric feeding. Behavioral responses were video recorded during feeding at 7 and 15 days of postnatal age and at 32 weeks of postmenstrual age. The odds ratio (OR) of manifest behavioral stress was calculated by means of logistic regression.

RESULTS

A significantly higher risk of a behavioral stress response in bolus-fed infants compared with continuous-fed infants at 15 days of age was observed, [adjusted OR=4.1 (95% confidence interval: 1.1-15.4)]. A similar difference was observed at 32 weeks of postmenstrual age [adjusted OR=4.2 (95% confidence interval: 1.0-17.8)]. In addition, bolus-fed infants showed statistically significant higher need of behavioral and physiologic stabilization during feeding.

DISCUSSION

This trial suggests that continuous feeding is associated with lower behavioral stress response as compared with bolus feeding among very low birth weight infants, in early postnatal life.

Prenatal origins of adult disease

PURPOSE OF REVIEW

Human epidemiological and animal studies show that many chronic adult conditions have their antecedents in compromised fetal and early postnatal development. Developmental programming is defined as the response by the developing mammalian organism to a specific challenge during a critical time window that alters the trajectory of development with resulting persistent effects on phenotype. Mammals pass more biological milestones before birth than any other time in their lives. Each individual's phenotype is influenced by the developmental environment as much as their genes. A better understanding is required of gene-environment interactions leading to adult disease.

RECENT FINDINGS

During development, there are critical periods of vulnerability to suboptimal conditions when programming may permanently modify disease susceptibility. Programming involves structural changes in important organs; altered cell number, imbalance in distribution of different cell types within the organ, and altered blood supply or receptor numbers. Compensatory efforts by the fetus may carry a price. Effects of programming may pass across generations by mechanisms that do not necessarily involve structural gene changes. Programming often has different effects in males and females.

SUMMARY

Developmental programming shows that epigenetic factors play major roles in development of phenotype and predisposition to disease in later life.

Maternal behavior predicts infant cortisol recovery from a mild everyday stressor

BACKGROUND

In the very first years of life, parenting is considered to be important for the regulation of the infant's emotional and physiological states. In the present study, three-month-old infants' cortisol responses (reactivity and recovery) to a mild everyday stressor, namely being taken out of the bath, were examined in relation to the quality of maternal behavior. It was hypothesized that a higher quality of maternal behavior towards the infant predicted lower cortisol reactivity as well as a better recovery from the reaction.

METHOD

The participants were 64 infants (34 boys and 30 girls) and their mothers. Maternal behavior (sensitivity and cooperation) towards the infant during the bathing routine was rated from videotapes. Salivary cortisol was obtained from the infants three times: before the bathing routine (T1), and 25 minutes (T2) and 40 minutes (T3) after the infants were taken out of the bath.

RESULTS

The infants reacted with a significant increase in cortisol to the stressor (from 6.8 nmol/l to 9.9 nmol/l), and regression analysis showed that the higher the quality of maternal behavior the better the cortisol recovery from the stressor.

CONCLUSION

Our findings indicate the potential importance of social processes for physiological recovery from everyday stressful situations in infants.

Augmented hypothalamic corticotrophin-releasing hormone mRNA and corticosterone responses to stress in adult rats exposed to perinatal hypoxia

Stressful events before or just after parturition alter the subsequent phenotypical response to stress in a general process termed programming. Hypoxia during the period before and during parturition, and in the postnatal period, is one of the most common causes of perinatal distress, morbidity, and mortality. We have found that perinatal hypoxia (prenatal day 19 to postnatal day 14) augmented the corticosterone response to stress and increased basal corticotrophin-releasing hormone (CRH) mRNA levels in the parvocellular portion of the paraventricular nucleus (PVN) in 6-month-old rats. There was no effect on the levels of hypothalamic parvocellular PVN vasopressin mRNA, anterior pituitary pro-opiomelanocortin or CRH receptor-1 mRNA, or hippocampus glucocorticoid receptor mRNA. We conclude that hypoxia spanning the period just before and for several weeks after parturition programmes the hypothalamic-pituitary-adrenal axis to hyper-respond to acute stress in adulthood, probably as a result of drive from the parvocellular CRH neurones.

Maternal stress and behavior modulate relationships between neonatal stress, attention, and basal cortisol at 8 months in preterm infants

There is evidence that the developmental trajectory of cortisol secretion in preterm infants is altered, with elevated basal cortisol levels observed postnatally through at least 18 months corrected age (CA). This alteration is possibly due to neonatal pain-related stress. High cortisol levels might contribute to greater risk of impaired neurodevelopment. Since maternal factors are important for the regulation of infant stress responses, we investigated relationships between infant (neonatal pain-related stress, attention, cortisol) and maternal (stress, interactive behaviors) factors at age 8 months CA. We found that interactive maternal behaviors buffered the relationship between high neonatal pain-related stress exposure and poorer focused attention in mothers who self-reported low concurrent stress. Furthermore, in preterm infants exposed to high concurrent maternal stress and overwhelming interactive maternal behaviors, higher basal cortisol levels were associated with poor focused attention. Overall, these findings suggest that maternal factors can influence the cognitive resilience at 8 months of preterm infants exposed to early life stress.

Levels of bone collagen markers in preterm infants: relation to antenatal glucocorticoid treatment

Although the beneficial effects of antenatally administered glucocorticoids are well documented, data on the potential of adverse consequences are limited. The objective of this study was to determine the effects of antenatally administered glucocorticoids on biochemical markers of bone metabolism of 55 preterm infants with a gestational age of 24-34 weeks who were enrolled in the study. Neonates were divided into two groups according to antenatal exposure to corticosteroids. There were no significant differences between the groups in clinical characteristics and anthropometric variables. We studied blood levels of osteocalcin (OC), carboxy-terminal propeptide of type I procollagen (PICP), and carboxy-terminal telopeptide of type I collagen (ICTP) at the time of delivery, on postnatal day 10, and at 2 and 4 months of life. Comparing the groups, we found statistically significant reduction in PICP levels at birth in corticosteroid-exposed neonates (P < 0.05). The levels of bone markers increased progressively on the first days of life. There were no significant differences between groups in bone markers at 10 days or at 2 and 4 months of life. We found no significant difference for bone markers between groups of infants exposed to single or repeated maternal corticosteroid treatments. In summary, antenatal glucocorticoid treatments are suggested to have a negative impact on fetal bone formation as reflected by low PICP levels at birth. However, this negative effect on bone markers seems to be a temporary effect that subsides on the first days of life and afterward.

Cortisol stimulates system A amino acid transport and SNAT2 expression in a human placental cell line (BeWo)

Both placental system A activity and fetal plasma cortisol concentrations are associated with intrauterine growth retardation, but it is not known if these factors are mechanistically related. Previous functional studies using hepatoma cells and fibroblasts produced conflicting results regarding the regulation of system A by cortisol. Using the b30 BeWo choriocarcinoma cell line, we investigated the regulation of system A by cortisol. System A function was analyzed using methyl amino isobutyric acid (MeAIB) transcellular transport studies. Transporter expression [system A transporter (SNAT)1/2] was studied at the mRNA and protein levels using Northern and Western blotting, respectively. Localization was carried out using immunocytochemistry. The [(14)C]MeAIB transfer rate across BeWo monolayers after preincubation with cortisol for 24 h was significantly increased compared with control. This was associated with a relocalization of the SNAT2 transporter at lower cortisol levels and significant upregulation of mRNA and protein expression levels at cortisol levels >1 microM. This is the first study to show functional and molecular regulation of system A by cortisol in BeWo cells. It is also the first study to identify which system A isoform is regulated. These results suggest that cortisol may be involved in upregulation of system A in the placenta to ensure sufficient amino acid supply to the developing fetus.