Antenatal exposure to betamethasone induces placental 11β-hydroxysteroid dehydrogenase type 2 expression and the adult metabolic disorders in mice

How is prenatal stress transmitted from the mother to the fetus?

Prenatal stress programmes long-lasting neuroendocrine and behavioural changes in the offspring. Often this programming is maladaptive and sex specific. For example, using a rat model of maternal social stress in late pregnancy, we have demonstrated that adult prenatally stressed male, but not prenatally stressed female offspring display heightened anxiety-like behaviour, whereas both sexes show hyperactive hypothalamo-pituitary-adrenal (HPA) axis responses to stress. Here, we review the current knowledge of the mechanisms underpinning dysregulated HPA axis responses, including evidence supporting a role for reduced neurosteroid-mediated GABAergic inhibitory signalling in the brains of prenatally stressed offspring. How maternal psychosocial stress is signalled from the mother to the fetuses is unclear. Direct transfer of maternal glucocorticoids to the fetuses is often considered to mediate the programming effects of maternal stress on the offspring. However, protective mechanisms including attenuated maternal stress responses and placental 11β-hydroxysteroid dehydrogenase-2 (which inactivates glucocorticoids) should limit materno-fetal glucocorticoid transfer during pregnancy. Moreover, a lack of correlation between maternal stress, circulating maternal glucocorticoid levels and circulating fetal glucocorticoid levels is reported in several studies and across different species. Therefore, here we interrogate the evidence for a role for maternal glucocorticoids in mediating the effects of maternal stress on the offspring and consider the evidence for alternative mechanisms, including an indirect role for glucocorticoids and the contribution of changes in the placenta in signalling the stress status of the mother to the fetus.

The effect of time interval between antenatal corticosteroid administration and delivery on outcomes in late preterm neonates born to mothers with diabetes: a retrospective cohort study

Objectives

The study aims to investigate whether the time interval between administering antenatal corticosteroids (ACS) and delivery influences the neonatal outcomes in late preterm (LPT) neonates (34 + 0 to 36 + 6 weeks) born to mothers with diabetes.

Study design

This retrospective cohort study included women with any type of diabetes who gave birth between 34 + 0 weeks and 36 + 6 weeks of gestation. Based on the time interval between the first dose of corticosteroid and delivery, the cases were stratified into the following groups: <2, 2-7, and >7 days. Women unexposed to ACS served as the control group. The primary outcomes included the incidence of neonatal hypoglycemia and respiratory distress syndrome/transient tachypnea of the newborn. Multivariate logistic regression was used to assess the relationship between the time interval and neonatal outcomes and adjust for potential confounders.

Results

The study enrolled a total of 636 parturients. Among them, 247 (38.8%) delivered within 2 days after ACS administration, 169 (26.6%) within 2-7 days, and 126 (19.8%) at >7 days. Baseline characteristics such as type of diabetes, methods of glycemic control, preterm premature rupture of membrane, placenta previa, cesarean delivery, indication for delivery, percentage of large for gestational age, birth weight, and HbA1c in the second or third trimester were significantly different among the four groups. The multivariate analysis showed no statistically significant difference in the incidence of primary or secondary neonatal outcomes between the case and control groups.

Conclusions

ACS treatment was not associated with neonatal hypoglycemia and respiratory outcomes in LPT neonates born to diabetic mothers, regardless of the time interval to delivery.

11β-hydroxysteroid dehydrogenases and biomarkers in fetal development

It is known that basal glucocorticoid levels in utero are essential for regulating fetal development and maturation, and determine the fate of later life. Recently, more and more studies suggest that adverse prenatal environments may cause abnormal maternal glucocorticoid levels in utero. 11β-hydroxysteroid dehydrogenases (11β-HSDs) are widely distributed in the target organs of glucocorticoids (GCs) and mineralocorticoids. 11β-HSDs is involved in fetal physiological and pathological development by activating or inactivating GCs. Prenatal adverse environments (including exogenous and maternal environments) can affect the expression and activity of 11β-HSDs in the placenta and fetus via multiple pathways. It induces abnormal local glucocorticoid levels in fetal multiple tissues, fetal developmental programming and homeostasis changes, and the susceptibility to various diseases after birth. We also discuss the interventions of 11β-HSDs inhibitors on fetal developmental programming and susceptibility to multiple diseases. Finally, we propose that 11β-HSD2 can be used as a molecular target for fetal developmental toxicity, while 11β-HSD1 can be regarded as an intervention target to prevent fetal-originated diseases. This review will provide a theoretical basis for the early prevention and treatment of fetal-originated diseases.

Progesterone partially recovers placental glucose transporters in dexamethasone-induced intrauterine growth restriction

RESEARCH QUESTION

How does progesterone improve fetal outcome and change the expression of placental glucose transporters (GLUT) in dexamethasone-induced intrauterine growth restriction (IUGR)?

DESIGN

A total of 64 rats were divided randomly into four different treatment groups based on daily i.p. injections of either saline or dexamethasone in the presence or absence of progesterone. Injections started on the 15th day of gestation (15dg) and lasted until the day of sacrifice at 19dg or 21dg. Maternal plasma progesterone concentrations were measured by enzyme-linked immunosorbent assay. The gene and protein expression of placental GLUT1 and GLUT3 were evaluated in the placental labyrinth and basal zones by real-time polymerase chain reaction and Western blotting, respectively. The localization of GLUT1 and GLUT3 was evaluated by immunohistochemistry.

RESULTS

Dexamethasone induced significant decreases in maternal serum progesterone concentrations (P = 0.029) and placental (P < 0.001) and fetal body (P = 0.009) weights. Dexamethasone also reduced the expression of GLUT1 in the labyrinth zone (P = 0.028) and GLUT3 in both the labyrinth (P = 0.002) and basal zones (P = 0.026). Coadministration of dexamethasone and progesterone prevented the reduction in fetal body weight, placental weight and placental GLUT expression compared with that seen in dexamethasone-treated groups.

CONCLUSION

These results suggest that progesterone prevents the significant reduction in fetal and placental weights in dexamethasone-induced IUGR, possibly through improving the expression of placental GLUT.

Effects of Maternal Chewing on Prenatal Stress-Induced Cognitive Impairments in the Offspring via Multiple Molecular Pathways

We aimed to investigate the effects of maternal chewing on prenatal stress-induced cognitive impairments in the offspring and to explore the molecular pathways of maternal chewing in a mice model. Maternal chewing ameliorated spatial learning impairments in the offspring in a Morris water maze test. Immunohistochemistry and Western blot findings revealed that maternal chewing alleviated hippocampal neurogenesis impairment and increased the expression of hippocampal brain-derived neurotrophic factor in the offspring. In addition, maternal chewing increased the expression of glucocorticoid receptor (GR) and 11β-hydroxysteroid dehydrogenase isozyme 2 (11β-HSD2) and decreased the expression of 11β-HSD1 in the placenta, thereby attenuating the increase of glucocorticoid in the offspring. Furthermore, maternal chewing increased the expression of 11β-HSD2, FK506-binding protein 51 (FKBP51) and FKBP52 and decreased the expression of 11β-HSD1, thereby increasing hippocampal nuclear GR level. In addition, maternal chewing attenuated the increase in expression of DNMT1 and DNMT3a and the decrease in expression of histone H3 methylation at lysine 4, 9, 27 and histone H3 acetylation at lysine 9 induced by prenatal stress in the offspring. Our findings suggest that maternal chewing could ameliorate prenatal stress-induced cognitive impairments in the offspring at least in part by protecting placenta barrier function, alleviating hippocampal nuclear GR transport impairment and increasing the hippocampal brain-derived neurotrophic factor (BDNF) level.

Determinants of neonatal hypoglycemia after antenatal administration of corticosteroids (ACS) for lung maturation: Data from two referral centers and review of the literature

BACKGROUND

A correlation between ACS and neonatal hypoglycemia has been recently demonstrated.

AIMS

The aim of the study was to evaluate the determinants of neonatal hypoglycemia in women exposed to ACS for respiratory distress syndrome prevention.

MATERIAL AND METHODS

Retrospective, multicenter, cohort study conducted in two Tertiary University Units. All fetuses delivered from 2016 to 2017 after ACS (two doses i.m. of Betamethasone 12 mg 24 h apart) were considered eligible for the study purpose. The primary outcome was the incidence of hypoglycemia, defined as a glycemic value ≤45 mg/dl within the first 48 h of neonatal life. The effect on neonatal glycaemia due to timing (interval from exposure to delivery) and type (single completed, single partial or repeated course) of ACS administration was also assessed.

RESULTS

Overall, 99 neonates met the inclusion criteria. Hypoglycemia occurred in 38/99 (38.4%) of the included newborns. Compared to normoglycemic neonates, those with hypoglycemia had lower gestational age at delivery (33.06 ± 3.37 vs. 35.94 ± 3.17 g; p < 0.0001). Lower birthweight (1747.28 ± 815.29 vs. 2499.24 ± 780.51 g; p < 0.0001), a shorter interval time from administration to delivery (1.85 ± 2.59 vs. 3.34 ± 3.39 weeks; p = 0.02) and a higher incidence of single partial course (23.7 vs. 8.72%; p = 0.03). Multivariate logistic regression found that only birthweight was significantly associated with neonatal hypoglycemia (OR 0.4 95% CI -1.16/-0.04; p < 0.038).

CONCLUSION

Hypoglycemia occurs in a large proportion of fetuses exposed to ACS independently from the type of exposure (single partial/single completed) and from the time interval between ACS administration and delivery. Birthweight seems to be the strongest determinant for the occurrence neonatal hypoglycemia after antenatal administration of steroids for lung maturation.