[Fetal programming as a cause of chronic diseases in adult life]

Prenatal Cafeteria Diet Primes Anxiety-like Behavior Associated to Defects in Volume and Diffusion in the Fimbria-fornix of Mice Offspring

Prenatal exposure to high-energy diets primes brain alterations that increase the risk of developing behavioral and cognitive failures. Alterations in the structure and connectivity of brain involved in learning and memory performance are found in adult obese murine models and in humans. However, the role of prenatal exposure to high-energy diets in the modulation of the brain's structure and function during cognitive decline remains unknown. We used female C57BL6 mice (n = 10) exposed to a high-energy diets (Cafeteria diet (CAF)) or Chow diet for 9 weeks (before, during and after pregnancy) to characterize their effect on brain structural organization and learning and memory performance in the offspring at two-month-old (n = 17). Memory and learning performance were evaluated using the Y-maze test including forced and spontaneous alternation, novel object recognition (NORT), open field and Barnes maze tests. We found no alterations in the short- or long-time spatial memory performance in male offspring prenatally exposed to CAF diet when compared to the control, but they increased time spent in the edges resembling anxiety-like behavior. By using deformation-based morphometry and diffusion tensor imaging analysis we found that male offspring exposed to CAF diet showed increased volume in primary somatosensory cortex and a reduced volume of fimbria-fornix, which correlate with alterations in its white matter integrity. Biological modeling revealed that prenatal exposure to CAF diet predicts low volume in the fimbria-fornix, which was associated with anxiety in the offspring. The findings suggest that prenatal exposure to high-energy diets prime brain structural alterations related to anxiety in the offspring.

Vitamin D receptor gene polymorphisms and haplotypes in the etiology of recurrent miscarriages

A few years ago it was shown that disturbed metabolism of the vitamin D/receptor (VD/VDR) complex may be important in the etiology of spontaneous abortion, as well as in the etiology of recurrent miscarriages (RM). The goal of this study was to investigate the association between four maternal VDR polymorphisms as well as haplotypes settings and RM occurrence in a Polish population of women in reproductive age. A total of 230 women were recruited to this study (110 with RM, 120 consecutively recruited age-matched healthy women with at least two full-term pregnancies and with no history of miscarriages). DNA samples were genotyped for VDR polymorphisms: FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236). Significant differences in genotype distributions and allele frequencies between case and control groups were observed in VDR BsmI polymorphism (GG vs. GA and AA, OR = 0.56, p = 0.036 and OR = 1.49, p = 0.035, respectively). The best evidence of an association with RM prevention was observed for the TTGT haplotype, which was more frequent among controls than cases even after permutation test (0.09 vs. 0.017, p = 0.0024). Other haplotypes were also significantly more frequent in the control group: TGT (rs7975232, rs1544410, rs2228570), TG (rs7975232, rs1544410), TTG (rs731236, rs7975232, rs1544410), TT (rs731236, rs7975232). Our research indicated the possible role of VDR BsmI genetic polymorphism in RM etiology, suggesting at the same time the active role of maternal VD metabolism and its influence on pregnancy outcome. The significant influence of several maternal haplotypes was shown to prevent RM occurrence.

Antenatal Hypoxia and Programming of Glucocorticoid Receptor Expression in the Adult Rat Heart

Glucocorticoid receptor (GR) signaling is critical for development and function of the heart. Our previous study demonstrated that gestational hypoxia induced epigenetic repression of the GR gene in the developing heart. The present study aims to determine that the alterations of promoter methylation level and epigenetic repression of the GR gene in the developing heart in response to maternal hypoxia is sustained in adult offspring and potential gender differences in the programming of GR gene. Pregnant rats were treated with 10.5% O₂ from gestational day 15 (E15) to 21 (E21). Hearts were isolated from 5-month-old male and female offspring with the developing stage being equivalent to 18-year-old human. GR mRNA and protein abundance was determined with real time qRT-PCR and Western blot. GR gene promoter methylation and binding of transcription factors were measured with methylated DNA immunoprecipitation (MeDIP) and Chromatin immunoprecipitation (ChIP). The results showed that antenatal hypoxia significantly decreased the expression of GR mRNA and protein in the hearts of adult male offspring, but not in females, which is ascribed to the differential changes of alternative exon1 mRNA variants of GR gene in male and female hearts in response to prenatal hypoxia. In addition, the downregulation of GR expression in the male heart was correlated with increased methylation levels of CpG dinucleotides in promoters of exon 1₄, 1₅, 1₆, 1₇, and 1₁₀, which resulted in a decrease in the binding of their transcription factors. Thus, the study reveals that antenatal hypoxia results in a reprogramming and long-term change in GR gene expression in the heart by hypermethylation of GR promoter in a sex-differential pattern, which provides a novel mechanism regarding the increased vulnerability of heart later in life with exposure of prenatal hypoxia.

Glucocorticoid-activation system mediated glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis programming alteration of adrenal dysfunction induced by prenatal caffeine exposure

Glucocorticoids play a major factor in fetal maturation and fate decision after birth. We have previously demonstrated that prenatal caffeine exposure (PCE) resulted in adrenal dysplasia. However, its molecular mechanism has not been clarified. In the present study, a rat model of intrauterine growth retardation (IUGR) was established by PCE, and offspring were sacrificed. Moreover, NCI-H295 A cells were used to confirm glucocorticoid-related molecular mechanism. Results showed that PCE fetal weight decreased, and the IUGR rate increased, while serum corticosterone levels increased but insulin-like growth factor 1 (IGF1) levels decreased. Fetal adrenals exhibited an activated glucocorticoid-activation system, and the downregulated expression of IGF1 signal pathway and steroidal synthetases. For adult rats, there was no significant change in the glucocorticoid-activation system in the PCE group, the IGF1 signal pathway showed increased trend, and the expression levels of adrenal steroidal synthetases were close to normal. The data in vitro showed that the cortisol of 1200 nM can inhibit the expression of adrenocortical cell steroidal synthetases and IGF1 signal pathway when compared with the control. Meanwhile, the glucocorticoid-activation system was activated while GR inhibitor mifepristone can reverse the effect of cortisol. Furthermore, cortisol can also promote GR into the nucleus after its activation. Based on these findings, we speculated that high concentrations of glucocorticoid in utero led to GR in the nucleus through its activation and then inhibited the IGF1 signaling pathway by activating the glucocorticoid-activation system, which could further downregulate steroid synthesis.

Excitotoxicity and compensatory upregulation of GAD67 in fetal rat hippocampus caused by prenatal nicotine exposure are associated with inhibition of the BDNF pathway

Prenatal nicotine exposure (PNE) can cause hypersensitivity of hypothalamic-pituitary-adrenal (HPA) axis in offspring with intrauterine growth retardation. The purpose of this study was to explore the original mechanism of intrauterine development that mediates hypersensitivity of the HPA axis in offspring due to PNE. Pregnant Wistar rats were injected subcutaneously with 2 mg/kg·d of nicotine on the 9th to the 20th gestational day (GD9-GD20) and the fetuses were extracted at GD20. Compared with the control group, fetal rats by PNE showed increased hippocampal apoptosis, reduced synaptic plasticity and downregulation of the brain-derived neurotrophic factor (BDNF) pathway, whereas glutamic acid decarboxylase 67 (GAD67) expression was upregulated. Rat fetal hippocampal H19-7/IGF1R cell lines were treated with different concentrations of nicotine (1, 10 and 100 μM) for 3 days, the extracellular fluid glutamate (Glu) level increased and similar effects were observed as in vivo. Intervention treatments caused the opposite results. These results indicated that PNE downregulates the BDNF pathway and mediates the hippocampal excitotoxicity; then, the compensatory upregulation of GAD67 causes the imbalance of signal output in the fetal hippocampus. The negative feedback regulation of the paraventricular hypothalamic nucleus by the hippocampus is unbalanced, eventually causing hypersensitivity of the HPA axis of the offspring.

Prenatal caffeine exposure-induced adrenal developmental abnormality in male offspring rats and its possible intrauterine programming mechanisms

Glucocorticoid (GC) is a major factor for fetal tissue maturation and fate decision after birth. We previously demonstrated that prenatal caffeine exposure (PCE) suppressed fetal adrenal steroidogenesis and resulted in adrenal dysplasia. However, whether these changes play a role until adulthood and its intrauterine programming mechanisms remain unknown. In the present study, a rat model of intrauterine growth retardation (IUGR) was established by PCE, male fetuses and adult offspring were sacrificed at postnatal day (PD) 1, PD7, PD35, PD100 and PD168, respectively. Results showed that the PCE fetal weight decreased and the IUGR rate increased, while the serum corticosterone (CORT) level increased but the insulin-like growth factor 1 (IGF1) level decreased. Fetal adrenal exhibited an enhanced GC-activation system (11β-hydroxysteroid dehydrogenases/corticoid receptors/CCAAT/enhancer binding proteins), an inhibited IGF1 pathway and steroid synthesis function. After birth, the serum CORT levels in the PCE offspring were increased in the early period followed by falling in the later stage, while the serum IGF1 level change was the opposite and was accompanied by an obvious catch-up growth. Furthermore, the adrenal GC-activation system was inhibited but the IGF1 signaling pathway was enhanced, resulting in a compensatory increase of adrenal steroidogenesis, and the expression of steroidal synthetase was consistent with that of the IGF1 signaling pathway. Based on these findings, we proposed "two-programming mechanisms" for PCE-induced adrenal abnormality: the "first programming" mechanism is a lower function of adrenal steroidogenesis, and prenatal and postnatal adrenal structural and functional abnormalities triggered by the intrauterine GC-IGF1 axis programming-mediated by the GC-activation system that acts as "the second programming" mechanism.

Postnatal growth outcomes and influence of maternal gestational weight gain: a prospective cohort study in rural Vietnam

Background

Suboptimal weight gain during pregnancy may result in adverse outcomes for both the mother and child, including increased risk of pre-eclampsia and gestational diabetes, delivery of low birth weight and small-for-gestational age (SGA) infants, and preterm delivery. The objectives of this study were to identify maternal predictors of rate of weight gain in pregnancy, and to evaluate the association of gestational weight gain with infant postnatal growth outcomes.

Methods

We conducted a prospective cohort study of infants born to women who had previously participated in a double-blind cluster randomized controlled trial of antenatal micronutrient supplementation, in Ha Nam province, Vietnam. Pregnant women (n = 1258) were seen at enrolment and 32 weeks gestation, and infants (n = 965) were followed until 6 months of age. Primary outcome was infant anthropometric indicators at 6 months of age (weight for age, length for age, weight for height z scores), and infant weight gain velocity during the first 6 months of life.

Results

Low body mass index (<18.5 kg/m²) was present in 26% of women, and rate of gestational weight gain was 0.4 kg per week [SD 0.12]. Rate of weight gain during pregnancy was significantly associated with infant weight-for-age (MD 1.13, 95% CI 0.58 to 1.68), length-for-age (MD 1.11, 95% CI 0.66 to 1.55), weight-for-length z scores (MD 0.63, 95% CI 0.07 to 1.19), and infant weight gain velocity during the first 6 months of life (MD 93.6 g per month, 95% CI 8.2 to 179.0).

Conclusions

Rate of gestational weight gain is predictive of postnatal growth at six months of age in this setting. Public health programs should be targeted towards improving body mass index and weight gain in pregnant women in rural Vietnam.