Placental 11beta-HSD2 activity, early postnatal clinical course, and adrenal function in extremely low birth weight infants

Alterations of adrenal steroidomic profiles in preterm infants at birth

OBJECTIVE

Preterm infants have relative adrenal and kidney immaturity. Recently, we linked their urine sodium loss to a hypoaldosteronism at variance with an appropriate stimulation of the renin-angiotensin system. To investigate this defective aldosterone secretion, we analyse the biosynthesis pathways of adrenal steroids in neonates according to gestational age (GA).

DESIGN

Multicentre study (Premaldo) including 152 neonates classified into three groups: group 1 (very preterm (VPT)): <33  gestational weeks (GW); group 2 (preterm (PT)): 33-36 GW and group 3 (term (T)): ≥GW.

METHOD

Steroidomic profiles of mineralocorticoids, glucocorticoids and adrenal androgens were established from umbilical cord at birth (n=152) and peripheral blood at day 3 (n=70) using a recently developed liquid chromatography mass spectrometry method (LC-MS/MS). The enzymatic activity of each biosynthesis step was estimated by the product-to-substrate ratio.

RESULTS

At birth, VPT infants exhibit a global defect in adrenal steroid synthesis pathways leading to lower levels of aldosterone, cortisol and androstenedione than in term infants. This defect was strongly related to GA. On day 3, steroid precursors (progesterone, 11-deoxycorticosterone (DOC), 17-hydroxyprogesterone(17-OH-P) and 11-deoxycortisol (S)) were higher in VPT and negatively correlated with GA. Despite of precursors' accumulation, aldosterone and cortisol were similar in the three groups. At birth and day 3, a low cortisol/11-deoxycortisol ratio was found in preterm infants, suggesting an 11-beta-hydroxylase activity (CYP11B1) deficiency.

CONCLUSIONS

At birth, VPT infants exhibit a global deficit in mineralocorticoids, glucocorticoids and adrenal androgens that attenuates on day 3 of life. Steroid profiling using LC-MS/MS provides evidence for a partial defect in 11-hydroxylase along with prematurity.

Effects of earthquake on perinatal outcomes: A Chilean register-based study

Background

Natural disasters increase the level population stress, including pregnant women, who can experience prenatal maternal stress, affecting the fetus and triggering perinatal complications, such as low birth weight, smaller head circumference, etc. However, little is known about effects of earthquake on perinatal outcomes.

Objective

To evaluate the effect of earthquake occurred on February 27, 2010 and perinatal outcomes of Chilean pregnant women, and to examine these effects by timing of exposure during pregnancy and newborn gender.

Methods

A register-based study was performed using data collected from women who had a vaginal delivery in a large private health center in Santiago, Chile, during 2009 and 2010. The study population was categorized according to exposure to earthquake and timing during gestation. Primary perinatal outcomes were gestational age at birth, birth weight, length and head circumference. Analyses adjusted for gender, gestational age at exposure, parity, maternal age and income.

Results

A total of 1,966 eligible vaginal deliveries occurred during 2009 and 2,110 in 2010. Birth weight was not affected by the trimester of exposure; however, length, head circumference and gestational age at birth were significantly different according to trimester of exposure and gender of newborn. In multivariable analysis, newborns were shorter by 2 mm, 5 mm and 4.5 mm, if they were exposed during their first, second and third trimester, respectively. Furthermore, newborns had a smaller head circumference by 1.2 mm and 1.5 mm if they were exposed during first and second trimester of gestation.

Conclusion

In this cohort, exposure to the February 2010 earthquake resulted in earlier delivery and reduced length and head circumference in the offspring. This association varied according to trimester of exposure and fetal gender. Health workers should include exposed to high levels of stress associated with natural disasters when assessing pregnancy risk factors.

Glucocorticoid Programming in Very Preterm Birth

Very preterm (i.e., <32 weeks of gestation) infants admitted to the neonatal intensive care unit are compromised in their abilities to respond adequately to common threats like hemodynamic changes and reduced energy supplies, which is partly attributable to adrenocortical insufficiency. Conversely, later in life, these infants show features of increased glucocorticoid bioactivity, such as abdominal fat distribution, raised blood pressure, insulin resistance and diabetes mellitus type 2. It has been suggested that the very preterm newborn responds to the adverse postnatal environment with a sustained elevation in hypothalamus-pituitary-adrenal axis activity that persists beyond infancy. This has implications for subsequent growth, body composition, metabolism, neurodevelopment and, ultimately, long-term disease risk. The mechanisms underpinning these associations are not fully elucidated yet. This review gives a brief summary of studies that investigated adrenocortical function in very preterm newborns and how the axis changes with age, as a possible explanation for the association between prematurity and long-term outcome.

Effects of prenatal maternal stress on serotonin and fetal development

Fetuses are exposed to many environmental perturbations that can influence their development. These factors can be easily identifiable such as drugs, chronic diseases or prenatal maternal stress. Recently, it has been demonstrated that the serotonin synthetized by the placenta was crucial for fetal brain development. Moreover, many studies show the involvement of serotonin system alteration in psychiatric disease during childhood and adulthood. This review summarizes existing studies showing that prenatal maternal stress, which induces alteration of serotonin systems (placenta and fetal brain) during a critical window of early development, could lead to alteration of fetal development and increase risks of psychiatric diseases later in life. This phenomenon, termed fetal programming, could be moderated by the sex of the fetus. This review highlights the need to better understand the modification of the maternal, placental and fetal serotonin systems induced by prenatal maternal stress in order to find early biomarkers of psychiatric disorders.

Biological Roles of Hydroxysteroid (11-Beta) Dehydrogenase 1 (HSD11B1), HSD11B2, and Glucocorticoid Receptor (NR3C1) in Sheep Conceptus Elongation

In sheep, the elongating conceptus synthesizes and secretes interferon tau (IFNT) as well as prostaglandins (PGs) and cortisol. The enzymes, hydroxysteroid (11-beta) dehydrogenase 1 (HSD11B1) and HSD11B2 interconvert cortisone and cortisol. In sheep, HSD11B1 is expressed and active in the conceptus trophectoderm as well as in the endometrial luminal epithelia; in contrast, HSD11B2 expression is most abundant in conceptus trophectoderm. Cortisol is a biologically active glucocorticoid and ligand for the glucocorticoid receptor (NR3C1 or GR) and mineralocorticoid receptor (NR3C2 or MR). Expression of MR is not detectable in either the ovine endometrium or conceptus during early pregnancy. In tissues that do not express MR, HSD11B2 protects cells from the growth-inhibiting and/or proapoptotic effects of cortisol, particularly during embryonic development. In study one, an in utero loss-of-function analysis of HSD11B1 and HSD11B2 was conducted in the conceptus trophectoderm using morpholino antisense oligonucleotides (MAOs) that inhibit mRNA translation. Elongating, filamentous conceptuses were recovered on Day 14 from ewes infused with control morpholino or HSD11B2 MAO. In contrast, HSD11B1 MAO resulted in severely growth-retarded conceptuses or conceptus fragments with apoptotic trophectoderm. In study two, clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing was used to determine the role of GR in conceptus elongation and development. Elongating, filamentous-type conceptuses (12-14 cm in length) were recovered from ewes gestating control embryos (n = 7/7) and gestating GR-edited embryos (n = 6/7). These results support the idea that the effects of HSD11B1-derived cortisol on conceptus elongation are indirectly mediated by the endometrium and are not directly mediated through GR in the trophectoderm.

ACTH and cortisol cord plasma concentrations in preterm and term infants

OBJECTIVE

To measure the adrenocorticotropic hormone (ACTH) and cortisol (F) cord plasma levels in preterm and term infants in relation to their mode of delivery.

STUDY DESIGN

We studied 180 newborns appropriate for gestational age (GA) with birth weights between 365 and 4380 g and GAs between 21 and 41 weeks divided into three groups: born by vaginal delivery (VD), elective cesarean section (ECS) and emergency cesarean section (EMCS). ACTH and F levels were valued with enzyme-linked immunosorbent assay testing. Median concentrations were compared between groups by Student's T-test for independent and paired data. Multiple regression analysis was used to investigate the effect of GA on F and ACTH concentrations.

RESULT

A significant positive correlation between GA and plasma concentrations of ACTH (P<0.05) was found in the whole population, but not between GA and F (P=NS). A significant positive correlation was found between GA and plasma concentrations of both ACTH (P=0.01) and F (P=0.03) in VD. In those born by ECS, we demonstrated a positive correlation not only between plasma concentrations of ACTH (P=0.0000) and F (P=0.00002), respectively, with GA, but also a correlation between ACTH and F (P=0.0004). No significant correlations were found in the EMCS group (P=NS).

CONCLUSION

Our results suggest simultaneous pituitary-adrenal maturation, which is complete only at term. The responsiveness of preterm babies to different stressful stimulations is similar to the terms' but quantitatively lower, and the secretion of ACTH and F may not suffice in severe pathological circumstances.

Differential expression of placental 11β-hydroxysteroid dehydrogenases in pregnant women with diet-treated gestational diabetes mellitus

Fetal exposure to excess glucocorticoid is one of the critical factors for the fetal origins of adult diseases. However, the mechanism of the local regulation of glucocorticoid activity in the human placenta of pregnancies complicated with gestational diabetes mellitus (GDM) has not been fully understood. We investigated placental 11β-hydroxysteroid dehydrogenases (11β-HSDs) expression, and analyzed their relationship with cortisol levels in maternal and umbilical vein. Pregnant women with GDM after diet intervention (n=23) or normal glucose tolerance (NGT, n=22) were studied at the community-based hospital. We collected maternal and umbilical venous cord blood and placental tissues from both groups. Explanted placentas from NGT were cultured with palmitic acid, dexamethasone, insulin or their mixture for 24-h. We examined plasma cortisol, cortisone to cortisol ratio, insulin, the homeostasis model assessment of insulin resistance index (HOMA-IR) and the insulin secretion index. Quantitative real-time PCR, Western blot and immunohistochemical assay were applied for the measurement of 11β-HSD1 and 11β-HSD2 mRNA and protein. GDM had higher maternal cortisol levels, HOMA-IR, insulin secretion index and higher cortisone to cortisol ratio in umbilical vein. No significant change in cortisol levels in umbilical vein and newborn weight was found. GDM placental 11β-HSD1 levels decreased while 11β-HSD2 increased. Treatment of placenta explants from NGT with palmitic acid, dexamethasone, insulin or their combination resulted in a significant drop of 11β-HSD1 and increase in 11β-HSD2. Differential expression of 11β-HSDs in diet-treated GDM placenta provides a protective mechanism for the fetus throughout the adverse environment of pregnancy by limiting excessive exposure of the fetus to glucocorticoid.

Gestational stress influences cognition and behavior

The developmental origins of disease or fetal programming model predicts that early exposures to threat or adverse conditions have lifelong consequences that result in harmful outcomes for health. The vast majority of the studies in support of the programming model in human beings are retrospective and most rely on surrogate measures of early experience such as birth weight or preterm birth. Recently, a small number of prospective studies have been reported that have documented the developmental consequences of exposures to stressful intrauterine conditions. These studies of gestational stress have clearly shown that fetal exposures to psychosocial and/or biological markers of adversity have significant and largely negative consequences for fetal, infant and child neurological development. Fetal exposure to stress, especially early in gestation, results in delayed fetal maturation and impaired cognitive performance during infancy and results in decreased brain volume in areas associated with learning and memory in children. The accumulating evidence supports the conclusion that fetal exposure to stress profoundly influences the nervous system, with consequences that persist into childhood and perhaps beyond.

Micro determination of cortisol and cortisone in umbilical cord blood by chemiluminescent high-performance liquid chromatography

A simple, sensitive and specific chemiluminescent high-performance liquid chromatography method, based on the luminol reaction, for determination of serum cortisol and cortisone, was established. In infants, placental 11beta-hydroxysteroid dehydrogenase type 2 enzyme (11beta-HSD2) activity may affect adrenal function early after birth. The cortisol-cortisone ratio of serum concentrations in umbilical cord blood is an indicator of placental 11beta-HSD2 activity. The optimum conditions for the luminol reaction were determined to be 1.5 mM luminol, 0.6 M sodium hydroxide, 0.15 mm potassium hexacyanoferrate(III) and 200 mM potassium hexacyanoferrate (II). The calibration curves for cortisol and cortisone exhibited good linearity. The correlation coefficients of the calibration curves were 0.996. The intra- and inter-day precisions were in the ranges: cortisol 7.0-12.2 and 4.4-9.2%, cortisone 5.3-7.0 and 6.2-9.9%. The recoveries of these steroids were in the ranges: cortisol 97-105%, cortisone 94-102%. The limits of detection were as follows: cortisol, 0.17 microg/dl; cortisone 0.15 microg/dl. This assay could be successfully applied to determination of the cortisol-cortiosone ratio of serum concentrations in umbilical cord bloods.

Sex-specific alterations in placental 11β-hydroxysteroid dehydrogenase 2 activity and early postnatal clinical course following antenatal betamethasone

Placental 11β-hydroxysteroid dehydrogenase-2 (11βHSD2) limits fetal glucocorticoid exposure and is associated with physiological stability in the premature newborn infant. Antenatal betamethasone alters 11βHSD2 activity and confers sex-specific advantages in neonatal outcome. We investigated the influence of betamethasone and sex on 11βHSD2 activity, neonatal adrenal function and clinical course in 24- to 36-wk gestation neonates from birth to day 5 of life. Univariate analyses demonstrated an interaction between timing of betamethasone exposure and sex for 11βHSD2 activity rate ( P = 0.02) and umbilical arterial cortisol ( P = 0.01). For infants born < 72 h following antenatal betamethasone, females had higher 11βHSD2 activity ( P < 0.01) and umbilical arterial cortisol ( P = 0.01) than males. Females born < 72 h of betamethasone exposure had higher day 1 urinary cortisol, if exposed to perinatal stress, than males ( P < 0.01). For infants born < 72 h after betamethasone exposure, 11βHSD2 activity was negatively correlated with Clinical Illness Severity Score score ( r = −0.79 P = 0.01) and positively correlated with mean arterial blood pressure ( r = 0.8 P = 0.01) only in females. Sex-specific placental 11BHSD2 autoregulation following antenatal betamethasone exposure may limit adrenal suppression in females influencing physiological stability following preterm birth. A lack of adjustment in 11βHSD2 and adrenal response may contribute to the increased incidence of poor outcome observed in preterm males.

Endostatin concentration in cord plasma predicts the development of bronchopulmonary dysplasia in very low birth weight infants

INTRODUCTION

Endostatin is an antiangiogenic growth factor. Together with proangiogenic growth factors it acts to shape the developing vasculature. Dysregulation of angiogenesis is a component in the pathogenesis of bronchopulmonary dysplasia.

OBJECTIVE

Our goal was to study whether the concentration of circulating endostatin at birth is associated with the development of bronchopulmonary dysplasia in very low birth weight infants.

PATIENTS AND METHODS

Endostatin concentration was measured in cord plasma from 92 very low birth weight infants (gestational age < 32 weeks; birth weight < 1500 g) and 48 healthy term infants (gestational age > 37 weeks; birth weight > 2500 g).

RESULTS

Endostatin concentration in very low birth weight infants was lower than in healthy term infants. Within the very low birth weight group no correlation existed between endostatin concentration and gestational age or relative birth weight. Very low birth weight infants who subsequently developed bronchopulmonary dysplasia had higher cord endostatin than those who did not. Higher endostatin concentration was associated with higher odds for bronchopulmonary dysplasia. Adjusted for gestational age, the odds for bronchopulmonary dysplasia were higher.

CONCLUSIONS

Circulating endostatin in term infants was higher than in very low birth weight infants, suggesting a temporal pattern for fetal endostatin concentration. In very low birth weight infants a high concentration of circulating endostatin at birth is associated with the subsequent development of bronchopulmonary dysplasia.