Brain-derived neurotrophic factor and ciliary neurotrophic factor in maternal plasma and umbilical cord blood from pre-eclamptic and physiological pregnancies

Modulation of matrix metalloproteases by ciliary neurotrophic factor in human placental development

Ciliary neurotrophic factor (CNTF) is a pleiotropic cytokine that signals through a receptor complex containing a specific subunit, CNTF receptor α (CNTFRα). The two molecules are constitutively expressed in key structures for human placental growth and differentiation. The possible role of CNTF in enhancing cell proliferation and/or invasion during placental development and remodelling was investigated using HTR-8/SVneo and BeWo cells, taken respectively as cytotrophoblast and syncytiotrophoblast models. In both cell lines, treatment with human recombinant (hr) CNTF activated JAK2/STAT3 signalling and inhibited the ERK pathway. Interestingly, in HTR-8/SVneo cells, 50 ng hrCNTF induced significant downregulation of matrix metalloprotease (MMP)-1 and significant upregulation of MMP-9. Moreover, pharmacological inhibition of JAK2/STAT3 signalling by AG490 and curcumin resulted in MMP-9 downregulation; it activated the ERK signalling pathway and upregulated MMP-1 expression. Collectively, these data suggest a role for CNTF signalling in extravillous cytotrophoblast invasion through the modulation of specific MMPs.

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.

Differences in Brain-Derived Neurotrophic Factor and Matrix Metalloproteinase-9 between Appropriate Neonates between Normal Birth Weight and Intrauterine Growth Restriction

BACKGROUND:

Intrauterine Growth Restriction (IUGR) was defined as the growth of the fetus less than its normal potential growth due to genetic and environmental factors. One of the most widely believed causes of IUGR was impaired uteroplacental mechanism from mother to fetus. Furthermore, factor which was thought to affect placental growth was due to the influence of Brain-Derived Neurotrophic Factor (BDNF) and Matrix Metalloproteinase (MMP-9) which play an important role in angiogenesis.

AIM:

This study aims to determine differences in Brain-Derived Neurotrophic Factor (BDNF) and moderately mature Matrix Metalloproteinase (MMP-9) between normal birth weight and intrauterine growth restriction.

MATERIAL AND METHODS:

The study design was a cross-sectional study at four hospitals in Padang city from August 2017-January 2018. The sample of this study was umbilical cord blood of appropriate gestational age neonate with normal birth weight (31 neonates) and IUGR (31 neonates) by consecutive sampling, samples taken from mothers who meet inclusion criteria. BDNF and MMP-9 levels were analysed by ELISA. The differences between normal birth weight and IUGR test were followed by unpaired T-test.

RESULTS:

The results showed that BDNF levels in normal neonates was 1.58 ± 0.23 ng/ml and in IUGR neonates were 1.25 ± 0.35 ng/ml (p = 0.001). MMP-9 levels in normal neonates was 1.09 ± 0.20 ng/ml and in IUGR neonates were 1.25 ± 0.35 (p = 0.03).

CONCLUSION:

The conclusion of this study was BDNF of moderately mature neonates was significantly higher in normal birth weight compared to intrauterine growth restriction, and the moderately high MMP-9 neonates were significantly higher in intrauterine growth restriction compared with normal birth weight.

The Effect of Anaesthetic Techniques on Maternal and Cord Blood Brain-Derived Neurotrophic Factor Levels

Objective

Brain-derived neurotrophic factor (BDNF), a member of neurotrophins, plays a critical role in neuronal tissue. In this study, the effects of spinal or general anaesthesia on cord and maternal peripheral blood BDNF and malondialdehyde (MDA) levels were investigated in patients undergoing elective caesarean section.

Methods

Eighty patients with term pregnancy were included. General anaesthesia was induced with intravenous (IV) propofol 2 mg kg^-1 in the general anaesthesia group (n=36). In the spinal anaesthesia group (n=35), hyperbaric bupivacaine 0.5%, 9 mg (1.8 mL) was injected intrathecally. Maternal blood samples were taken immediately after positioning the patient on the operating table (T1), before clamping the umbilical cord (T2) and 24 hours after the first sample was obtained (T3). Cord blood samples were drawn from the umbilical artery (T4).

Results

Maternal BDNF levels (pg mL^-1) measured at T2 time point were higher in the general anaesthesia group compared to the spinal anaesthesia group (p<0.001). Cord blood BDNF levels were higher in the general anaesthesia group compared to the spinal anaesthesia group (p<0.001). In both groups, cord blood BDNF levels were significantly lower compared to the maternal blood samples collected at any time point (p<0.001, for all). There was a negative association between both maternal and cord blood BDNF levels with maternal MDA and cord blood MDA levels, respectively (r=-0.379, p<0.001; r=-0.375, p=0.001, respectively).

Conclusion

The anaesthetic technique may have an influence on maternal peripheral and cord blood BDNF levels.

Regional changes of placental vascularization in preeclampsia: a review

Preeclampsia is characterized by vascular dysfunction and results in maternal and fetal morbidity and mortality. The placenta plays a critical role in the growth and development of the fetus, and recent studies indicate that placental architecture, oxygen availability, and oxidative stress indices vary across different regions of the placenta. Our earlier studies have reported altered maternal angiogenesis and differential placental gene expression and methylation patterns of angiogenic factors in women with preeclampsia when compared with normotensive women. We have also demonstrated lower maternal and placental neurotrophin (NT) levels in women with preeclampsia. Studies suggest that oxidative stress is associated with proteases like matrix metalloproteinases (MMPs) and growth factors like NTs and angiogenic factors known to be involved in the process of angiogenesis. Recently, we have reported regionwise differential oxidative stress, antioxidant enzyme activity, and NT levels in placenta from normotensive control women and women with preeclampsia. The current review describes the regional changes in the placenta and highlights the role of placental oxidative stress in influencing regional differences in the expression of angiogenic factors, MMPs, and NTs. This review discusses the need for further research on various growth factors and proteins involved in the process of placental development across different regions of the placenta. This would help to understand whether regional differences in these factors affect the growth and development of the fetus.