Placental and cord blood brain derived neurotrophic factor levels are decreased in nondiabetic macrosomia

Does brain-derived neurotrophic factor play a role in the association between maternal prenatal mental health and neurodevelopment in 2-year-old children?

OBJECTIVE

To evaluate the role of brain-derived neurotrophic factor (BDNF)-a crucial modulator of neural development and plasticity-in the association between prenatal maternal anxiety, depression, and perceived stress and child neurodevelopment in a prospective cohort study.

METHODS

We included 526 eligible mother-child pairs from the Shanghai Birth Cohort in the study. Maternal mental health was assessed at mid-pregnancy using Zung's Self-Rating Anxiety Scale, Center for Epidemiologic Studies Depression Scale, and Perceived Stress Scale. The concentration of BDNF in cord blood was measured by ELISA. The offspring neurodevelopment at 24 months of age was assessed using the Bayley Scales. Linear and non-linear regression models were used.

RESULTS

The average cord blood BDNF levels were higher in female newborns and those born via vaginal delivery, full term, and normal birth weight. Prenatal maternal anxiety (β = -0.32; 95 % CI: -0.55, -0.09), depression (β = -0.30; 95 % CI: -0.52, -0.08), and perceived stress (β = -0.41; 95 % CI: -0.71, -0.12) scores were negatively associated with social-emotional performance at 24 months of age. However, no significant associations were found between prenatal maternal anxiety, depression, or perceived stress at mid-pregnancy and cord blood BDNF levels, as well as between cord blood BDNF levels and child neurodevelopment.

LIMITATIONS

Maternal mental health at different timepoints during pregnancy and generalizability of the results warrant further assessment.

CONCLUSIONS

Prenatal mental health was not associated with cord blood BDNF level and that BDNF may not be a mediator in the association between prenatal mental health and child neurodevelopment.

Correlating maternal and cord-blood inflammatory markers and BDNF with human fetal brain activity recorded by magnetoencephalography: An exploratory study

Background

During gestation, the brain development of the fetus is affected by many biological markers, where inflammatory processes and neurotrophic factors have been of particular interest in the past decade.

Aim

This exploratory study is the first attempt to explore the relationships between biomarker levels in maternal and cord-blood samples and human fetal brain activity measured with non-invasive fetal magnetoencephalography (fMEG).

Method

Twenty-three women were enrolled in this study for collection of maternal serum and fMEG tracings immediately prior to their scheduled cesarean delivery. Twelve of these women had a preexisting diabetic condition. At the time of delivery, umbilical cord blood was also collected. Biomarker levels from both maternal and cord blood were measured and subsequently analyzed for correlations with fetal brain activity in four frequency bands extracted from fMEG power spectral densities.

Results

Relative power in the delta, alpha, and beta frequency bands exhibited moderate-sized correlations with maternal BDNF and cord-blood CRP levels before and after adjusting for confounding diabetic status. These correlations were negative for the delta band, and positive for the alpha and beta bands. Maternal CRP and cord-blood BDNF and IL-6 exhibited negligible correlations with relative power in all four bands. Diabetes did not appear to be a strong confounding factor affecting the studied biomarkers.

Conclusions

Maternal BDNF levels and cord-blood CRP levels appear to have a direct correlation to fetal brain activity. Our findings indicate the potential use of these biomarkers in conjunction with fetal brain electrophysiology to track fetal neurodevelopment.

Correlation of fetal heart rate dynamics to inflammatory markers and brain-derived neurotrophic factor during pregnancy

OBJECTIVES

This study aims to show the relation between biomarkers in maternal and cord-blood samples and fetal heart rate variability (fHRV) metrics through a non-invasive fetal magnetocardiography (fMCG) technique.

METHODS

Twenty-three women were enrolled for collection of maternal serum and fMCG tracings immediately prior to their scheduled cesarean delivery. The umbilical cord blood was collected for measurement of biomarker levels. The fMCG metrics were then correlated to the biomarker levels from the maternal serum and cord blood.

RESULTS

Brain-derived neurotrophic factor (BDNF) had a moderate correlation with fetal parasympathetic activity (0.416) and fetal sympathovagal ratios (-0.309; -0.356). Interleukin (IL)-6 also had moderate-sized correlations but with an inverse relationship as compared to BDNF. These correlations were primarily in cord-blood samples and not in the maternal blood.

CONCLUSIONS

In this small sample-sized exploratory study, we observed a moderate correlation between fHRV and cord-blood BDNF and IL-6 immediately preceding scheduled cesarean delivery at term. These findings need to be validated in a larger population.

Maternal exposure to fine particulate matter and brain-derived neurotrophic factor (BDNF) in the fetus: A prospective cohort study

Maternal exposure to ambient fine particulate matter (PM_2.5) during pregnancy has been associated with impaired neurobehavioral development in children. However, the specific mechanism remains unclear. Brain derived neurotrophic factor (BDNF) is an important growth factor in the nervous system. We evaluated the associations of maternal PM_2.5 exposures with fetal BDNF in the umbilical cord blood in a prospective cohort study. A total of 711 eligible mother-infant pairs from the Shanghai Birth Cohort were included in the current study. Daily maternal exposures to ambient PM_2.5 were assessed with a gap-filling approach at 1 * 1 km² resolution based on self-reported home addresses. The concentrations of BDNF in the cord blood were measured by ELISA. A linear regression model was applied to evaluate the association of maternal ambient PM_2.5 exposure with fetal BDNF level at birth. The median concentration of BDNF was 13,403 pg/ml. Vaginal deliveries and female infants had higher BDNF levels than cesarean deliveries and male infants. One natural log (ln) unit increase in maternal PM_2.5 exposure during the second trimester was significantly associated with - 0.20 (95% CI: -0.36, -0.05) ln-unit decrease in BDNF level in all births. These effects were stronger and more significant in vaginal deliveries and in male infants. Our study suggests that BDNF in the cord blood may serve as a potential biomarker in assessing the neurodevelopmental effects of maternal PM_2.5 exposure.

Cord serum brain-derived neurotrophic factor levels at birth associate with temperament outcomes at one year

Altered serum levels of brain-derived neurotrophic factor (BDNF) are consistently linked with neurological disorders. BDNF is also increasingly implicated in the pathogenesis of neurodevelopmental disorders, particularly those found more frequently in males. At birth, male infants naturally have significantly lower serum BDNF levels (∼10-20% lower than females), which may render them more vulnerable to neurodevelopmental disorders. We previously characterized serum BDNF levels in mothers and their newborn infants as part of the Grown in Wales Study. Here, we analyzed whether cord serum BDNF levels at birth correlate with sex-specific outcomes at one year. The Bayley Scale of Infant Development, Third Edition (BSID-III) and Laboratory Temperament Assessment Battery (Lab-TAB) tasks were used to assess infant behavior and neurodevelopment at 12-14 months (mean ± SD: 13.3 ± 1.6 months; 46% male; n = 56). We found no relationship between serum BDNF levels at birth and BSID-III neurodevelopmental outcomes (cognitive or language), nor with infant behaviors in the Lab-TAB unpredictable mechanical toy or maternal separation tasks. In the sustained attention task, there was a significant positive relationship between serum BDNF and infant negative affect (B = 0.06, p = 0.018) and, for boys only, between serum BDNF and intensity of facial interest (B = 0.03, p = 0.005). However, only the latter remained after correction for multiple testing. This sex-specific association between cord serum BDNF and a parameter of attention at 12-14 months provides some support for the hypothesis that reduced serum BDNF levels at birth are linked to an increased risk for neurodevelopmental disorders.

Brain-Derived Neurotrophic Factor in Gestational Diabetes: Analysis of Maternal Serum and Cord Blood Pairs and Comparison of Dietary- and Insulin-Dependent GDM

The Objective of our study was to investigate the influence of dietary (dGDM) and insulin-dependent (iGDM) gestational diabetes (GDM) on BDNF blood levels of corresponding maternal-neonatal pairs and compare them to pregnancies unaffected by GDM. Blood samples from 293 maternal-neonatal pairs were analyzed. Statistical analysis was performed using multiple regression analysis for association of log-transformed maternal and neonatal BDNF levels in relation to GDM, gestational age, neonatal sex, and mode of delivery. This was followed by a 2:1 matching of healthy and diabetic pairs. Maternal and neonatal BDNF levels were lowest in the iGDM group, followed by the dGDM group and healthy controls (maternal: healthy 665 ± 562 (26–2343) pg/mL vs. dGDM 593 ± 446 (25–1522) pg/mL vs. iGDM 541 ± 446 (68–2184) pg/mL; neonate: healthy 541 ± 464 (9.5–2802) pg/mL vs. dGDM 375 ± 342 (1–1491) pg/mL vs. iGDM 330 ± 326 (47–1384) pg/mL). After multiple regression analysis and additional 2:1 matching neonatal log-BDNF was significantly lower (−152.05 pg/mL, p = 0.027) in neonates of mothers with GDM compared to healthy pairs; maternal log-BDNF was also lower (−79.6 pg/mL), but did not reach significance. Our study is the first to analyze BDNF in matched maternal-neonatal pairs of GDM patients compared to a metabolically unaffected control group.

How neuroactive factors mediates immune responses during pregnancy: An interdisciplinary view

Pregnancy, from insemination to parturition, is a highly complex but well-orchestrated process that requires various organs and systems to participate. Immune system and neuroendocrine system are important regulators in healthy pregnancy. Dozens of neuroactive factors have been detected in human placenta, whether they are locally secreted or circulated. Among them, some are vividly studied such as corticotropin-releasing hormone (CRH), human chorionic gonadotropin (hCG), transforming growth factor-β (TGF-β), progesterone and estrogens, while others are relatively lack of research. Though the neuroendocrine-immune interactions are demonstrated in some diseases for decades, the roles of neuroactive factors in immune system and lymphocytes during pregnancy are not fully elucidated. This review aims to provide an interdisciplinary view on how the neuroendocrine system mediate immune system during pregnancy process.

Placental mtDNA copy number and methylation in association with macrosomia in healthy pregnancy

INTRODUCTION

Fetal growth and development depend on metabolic energy from placental mitochondria. However, the impact of placental mitochondria on the occurrence of macrosomia remains unclear. We aimed to explore the association between macrosomia without gestational diabetes mellitus (non-GDM) and changes in placental mitochondrial DNA (mtDNA) copy number and methylation.

METHODS

Fifty-four newborns with macrosomia and 54 normal birthweight controls were enrolled in this study. Placental mtDNA copy number and mRNA expression of nuclear genes related to mitochondrial replication or ATP synthesis-related genes were measured by real-time quantitative polymerase chain reaction (qPCR). Methylation levels of the non-coding regulatory region D-loop and ATP synthesis-related genes were detected by targeted bisulfite sequencing.

RESULTS

Newborns with macrosomia had lower placental mtDNA copy number and higher methylation rates of the CpG15 site in the D-loop region (D-CpG15) and CpG6 site in the cytochrome C oxidase III (COX3) gene (COX3-CpG6) than normal birth weight newborns. After adjusting for potential covariates (gestational age, prepregnancy BMI, and infant sex), decreased placental mtDNA copy number (adjusted odds ratio [aOR] = 2.09, 95% confidence interval [CI] 1.03-4.25), elevated methylation rate of D-CpG15 (aOR = 2.06, 95% CI 1.03-4.09) and COX3-CpG6 (aOR = 2.13, 95% CI 1.08-4.20) remained significantly associated with a higher risk of macrosomia.

DISCUSSION

Reduced mtDNA copy number and increased methylation levels of specific loci at mtDNA would increase the risk of macrosomia. However, the detailed molecular mechanism needs further identification.

Maternal diabetes-induced alterations in the expression of brain-derived neurotrophic factor in the developing rat hippocampus

Maternal diabetes during pregnancy affects the development of hippocampus in the offspring. Brain-derived neurotrophic factor (BDNF) has received increasing attention for its role in regulating the survival and differentiation of neuronal cells in developing and adult brain. In the current study, we evaluated the effects of maternal diabetes and insulin treatment on expression and distribution pattern of BDNF in the hippocampus of neonatal rats at the first two postnatal weeks. We found no differences in hippocampal expression of BDNF between diabetics with normal control or insulin treated neonatal rats at postnatal day (P0) (P > 0.05 each). Nevertheless, there was a marked BDNF downregulation in both sides' hippocampi of male/female diabetic group in two-week-old offspring (P ≤ 0.05 each). Furthermore, the numerical density of BDNF+ cells was significantly reduced in the right/left dentate gyrus (DG) of male and female newborns born to diabetic animals at all studied postnatal days (P ≤ 0.05 each). In addition, a lower number of reactive cells have shown in the all hippocampal subareas in the diabetic pups at P14 (P ≤ 0.05 each). Our results have demonstrated that the insulin-treatment improves some of the negative impacts of diabetes on the expression of hippocampal BDNF in the newborns. We conclude that diabetes in pregnancy bilaterally disrupts the expression of BDNF in the hippocampus of the both male and female newborns at early postnatal days. In addition, good glycemic control by insulin in the most cases is sufficient to prevent the alterations in expression of BDNF protein in developing hippocampus.

The placenta protects the fetal circulation from anxiety-driven elevations in maternal serum levels of brain-derived neurotrophic factor

Brain-derived neurotrophic factor (BDNF) plays crucial roles in brain function. Numerous studies report alterations in BDNF levels in human serum in various neurological conditions, including mood disorders such as depression. However, little is known about BDNF levels in the blood during pregnancy. We asked whether maternal depression and/or anxiety during pregnancy were associated with altered serum BDNF levels in mothers (n = 251) and their new-born infants (n = 212). As prenatal exposure to maternal mood disorders significantly increases the risk of neurological conditions in later life, we also examined the possibility of placental BDNF transfer by developing a new mouse model. We found no association between maternal symptoms of depression and either maternal or infant cord blood serum BDNF. However, maternal symptoms of anxiety correlated with significantly raised maternal serum BDNF exclusively in mothers of boys (r = 0.281; P = 0.005; n = 99). Serum BDNF was significantly lower in male infants than female infants but neither correlated with maternal anxiety symptoms. Consistent with this observation, we found no evidence for BDNF transfer across the placenta. We conclude that the placenta protects the developing fetus from maternal changes in serum BDNF that could otherwise have adverse consequences for fetal development.

Brain-derived neurotrophic factor (BDNF) expression and function in the mammalian reproductive Tract

BACKGROUND

Neurotrophins of the nerve growth factor family are soluble polypeptides that are best known for their role in nerve growth, survival and differentiation in the central nervous system. A growing body of literature shows that neurotrophins and their receptors are also expressed throughout the reproductive tract.

OBJECTIVE AND RATIONALE

Neurotrophins are key regulatory proteins in reproductive physiology during development and throughout adult life. Of the neurotrophins, the literature describing the expression and function of brain-derived neurotrophic factor (BDNF) and its high-affinity receptor, neurotrophin receptor kinase-2 (NTRK2), has been expanding rapidly. We therefore conducted a systematic inductive qualitative review of the literature to better define the role of the BDNF in the reproductive tract. We postulate that BDNF and NTRK2 are central regulatory proteins throughout the reproductive system.

SEARCH METHODS

An electronic search of Medline (PubMed) and Web of Science for articles relating to BDNF and the reproductive system was carried out between January 2018 and February 2019.

OUTCOMES

In the ovary, BDNF expression and levels have been linked with follicle organisation during ovarian development, follicle recruitment and growth and oocyte maturation. In the endometrium, BDNF is involved in cell proliferation and neurogenesis. In contrast, literature describing the role of BDNF in other reproductive tissues is sparse and BDNF-NTRK2 signalling in the male reproductive tract has been largely overlooked. Whilst estradiol appears to be the primary regulator of BDNF expression, we also identified reports describing binding sites for glucocorticoid and myocyte enhancer factor-2, a calcium-response element through activation of an N-methyl-D-aspartate (NMDA) receptor, and aryl hydrocarbon receptor nuclear transporter protein-4 (ARNT) response elements in promoter regions of the BDNF gene. Expression is also regulated by multiple microRNAs and post-translational processing of precursor proteins and intracellular shuttling. BDNF-NTRK2 signalling is modulated through tissue specific receptor expression of either the full-length or truncated NTRK2 receptor; however, the functional importance remains to be elucidated. Dysregulation of BDNF expression and circulating concentrations have been implicated in several reproductive disorders including premature ovarian failure, endometriosis, pre-eclampsia, intra-uterine growth restriction (IUGR) and several reproductive cancers.

WIDER IMPLICATIONS

We conclude that BDNF and its receptors are key regulatory proteins central to gonadal development, ovarian regulation and uterine physiology, as well as embryo and placenta development. Furthermore, dysregulation of BDNF-NTRK2 in reproductive diseases suggests their potential role as candidate clinical markers of disease and potential therapeutic targets.

Role of neurotrophins in pregnancy and offspring brain development

Neurotrophins are a family of functionally and structurally related proteins which play a key role in the survival, development, and function of neurons in both the central and peripheral nervous systems. Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), neurotrophin-3 (NT-3), and neurotrophin-4 (NT-4) are the family members of neurotrophins. Neurotrophins play a crucial role in influencing the development of the brain and learning and memory processes. Studies demonstrate that they also play crucial role in influencing reproductive and immune systems. Neurotrophins have been shown to influence various processes in the mother, placenta, and fetus during pregnancy. Development and maturation of feto-placental unit and the fetal growth trajectories are influenced by neurotrophins. In addition to neurotrophins, neuropeptides like neuropeptide Y also play a crucial role during various processes of pregnancy and during fetal brain development. Neurotrophins have also been shown to have a cross talk with various angiogenic factors and influence placental development. Alterations in the levels of neurotrophins and neuropeptides lead to placental pathologies resulting in various pregnancy complications like preeclampsia, intrauterine growth restriction and preterm births. Studies in animals have reported low levels of maternal micronutrients like folic acid, vitamin B₁₂ and omega-3 fatty acids influence brain neurotrophins resulting in impaired cognitive functioning in the offspring. Maternal nutrition is also known to affect the expression of neuropeptides. It is essential to understand the role of various neurotrophins across various stages of pregnancy and its relationship with neurodevelopmental outcomes in children. This will lead to early prediction of poor neurodevelopmental outcomes. The present review describes evidence describing the role of neurotrophins in determining pregnancy outcome and altered neurodevelopment in the offspring. The possible mechanism through which maternal nutrition influences neurotrophins and neuropeptides to regulate offspring brain development and function is also discussed.

Role of neurotrophins in pregnancy, delivery and postpartum

Neurotrophins (NTs) are a family of polypeptides whose functions have been extensively studied in the past two decades. In particular, Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF) play a major role in the development, nutrition and growth of the central and peripheral nervous system and in the pathogenesis of neurodegenerative, cardiometabolic and (auto)immune diseases. However, NGF and BDNF have subtle functions for follicular development, implantation, and placentation. This short narrative review summarizes the existing evidence, published between 2000 and 2019, about the role of NTs in many different conditions that might affect women during and after pregnancy such as preeclampsia, gestational diabetes, obesity, depression, anxiety, smoking and alcohol abuse. Literature suggests that the dysregulation of synthesis and release of NTs may lead to decisive effects on both maternal and fetal health. Some piece of evidences was found about a possible association between NGF/BDNF and breastfeeding. Additional studies on human models are necessary to further characterize the role of NTs in life-changing experiences like labor and delivery.

Cord blood leptin DNA methylation levels are associated with macrosomia during normal pregnancy

BACKGROUND

We previously demonstrated an association between placental leptin (LEP) methylation levels and macrosomia without gestational diabetes mellitus (non-GDM). This study further explored the association between LEP methylation in cord blood and non-GDM macrosomia.

METHOD

We carried out a case-control study of 61 newborns with macrosomia (birth weight ≥4000 g) and 69 newborns with normal birth weight (2500-3999 g). Methylation in the LEP promoter region was mapped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

Average cord blood LEP methylation levels were lower in macrosomia newborns than in control newborns (P < 0.001). Eleven CpG sites were associated with macrosomia. Multivariate logistic regression revealed that low LEP methylation levels [adjusted odds ratio (AOR) = 2.84, 95% confidence interval (CI): 1.72-4.17], high pre-pregnancy body mass index (AOR = 7.44, 95% CI: 1.99-27.75), long gestational age (AOR = 3.18, 95% CI: 1.74-5.79), high cord blood LEP concentration (AOR = 2.25, 95% CI: 1.34-3.77), and male newborn gender (AOR = 3.91, 95% CI: 1.31-11.69) significantly increased the risk of macrosomia.

CONCLUSIONS

Lower cord blood LEP methylation levels and certain maternal and fetal factors are associated with non-GDM macrosomia.

Developmental origins of adult health and disease: The metabolic role of BDNF from early life to adulthood

Accumulating evidence suggests that the origins of adult disease may occur during fetal life. Thus, the concept of "developmental programming" has been introduced and supported by epidemiological and experimental data. This concept supports the idea that the nutritional and hormonal status during pregnancy could interfere in metabolism control. The mechanisms responsible for this "developmental programming" remain poorly documented. Current research indicates that neurotrophins and particularly brain-derived neurotrophic factor (BDNF) may play a crucial role in this process. Although mainly expressed in the nervous system, BDNF and its receptor, tropomyosin-related kinase B (TrkB), are immunolocalized in several regions of the human placenta and have important functions during pregnancy. BDNF serves widespread roles in regulating energy homeostasis in both fetuses and adults, by controlling patterns of fetal growth, adult feeding and physical activity, and by regulating glucose metabolism in peripheral tissues. Impaired BDNF signaling may be implicated in the etiopathogenesis of the metabolic syndrome. Novel BDNF-focused interventions are being developed for obesity, diabetes and neurological disorders. The aim of this article is to provide a brief comprehensive literary review regarding the potential implications of BDNF in "developmental programming", through regulation of metabolism and energy balance from early life to adulthood.