Balanced levels of nerve growth factor are required for normal pregnancy progression

Single-nucleus RNA sequencing reveals distinct pathophysiological trophoblast signatures in spontaneous preterm birth subtypes

Spontaneous preterm birth (sPTB) poses significant challenges, affecting neonatal health and neurodevelopmental outcomes worldwide. The specific effects of placental trophoblasts on the pathological development of sPTB subtypes-preterm premature rupture of fetal membranes (pPROM) and spontaneous preterm labor (sPTL)-are not fully understood, making it crucial to uncover these impacts for the development of effective therapeutic strategies. Using single-nucleus RNA sequencing, we investigated transcriptomic and cellular differences at the maternal-fetal interface in pPROM and sPTL placentas. Our findings revealed distinct trophoblast compositions with pPROM characterized predominantly by extravillous trophoblasts (EVTs), while sPTL showed an abundance of syncytiotrophoblasts (STBs). Through cell differentiation and cell-to-cell communication analyses, other distinguishing factors were also found. In pPROM, heightened inflammation, oxidative stress, and vascular dysregulation with key pathways including tumor necrosis factor signaling, matrix metalloproteinase activation, and integrin-mediated cell adhesion, highlighted an invasive EVT profile potentially driven by hypoxic conditions and immune cell recruitment. In contrast, sPTL was marked by increased smooth muscle contraction, vascular remodeling, and altered signaling dynamics involving fibroblasts, including TGF-β and WNT pathways. Our study highlights the critical need to distinguish sPTB subtypes to improve diagnostic precision and therapeutic targeting. The molecular insights gained provide a foundation for future investigations aimed at functional validation of key pathways and exploration of trophoblasts on the development of sPTB. Ultimately, these findings pave the way for more personalized and effective interventions to mitigate adverse outcomes associated with preterm birth.

Analysis of β-nerve growth factor and its precursor during human pregnancy by immunoaffinity-liquid chromatography tandem mass spectrometry

β-Nerve growth factor (NGF) is a neurotrophin that plays a critical role in fetal development during gestation. ProNGF is the precursor form of NGF with a distinct biological profile. In order to investigate the role of NGF and proNGF in pregnant human females, a sensitive and selective immunoaffinity liquid chromatography-tandem mass spectrometry assay was developed and qualified to simultaneously measure the levels of total NGF (tNGF; sum of mature and proNGF) and proNGF using full and relative quantification strategies, respectively. The assay was used to determine serum tNGF and proNGF levels in the three gestational trimesters of pregnancy and in non-pregnant female controls. Mean tNGF ± SD were 44.6 ± 12.3, 42.6 ± 9.3, 65.4 ± 17.6 and 77.0 ± 17.8 pg/mL for non-pregnant, first, second, and third trimesters, respectively, demonstrating no significant increase in circulating tNGF between the control and the first trimester, and a moderate yet significant 1.7-fold increase through gestation. proNGF levels during the first trimester were unchanged compared to control. In contrast to tNGF, however, proNGF levels during gestation remained stable without significant changes. The development of this sensitive, novel immunoaffinity duplexed assay for both tNGF and proNGF is expected to enable further elucidation of the roles these neurotrophins play in human pregnancy as well as other models.

Association between proNGF receptors and apoptotic factors in human placentae

INTRODUCTION

Earlier studies have shown higher apoptosis in the pre-term placenta as compared to term. However, the exact mechanisms triggering these are not completely understood. Studies in neuronal and non-neuronal tissues have shown that the precursor form of NGF (proNGF) triggers apoptosis through preferential activation of p75NTR and sortilin receptors. We therefore, investigated placental expression of proNGF, mature NGF, p75NTR, co-receptor sortilin and their association with apoptosis. We further compared the levels of pro-protein convertase, furin between samples having high and low proNGF: mature NGF ratio.

METHODS

Placenta samples were collected from women delivering at term (≥37 weeks; n = 41) and preterm (<37 weeks; n = 44). The protein levels of NGF, proNGF, p75NTR, Bax, Bcl-2 and furin were estimated by ELISA. Mean values of variables between different groups were compared using the independent sample t-test and associations were studied by Pearson correlation analysis.

RESULTS

The placental mature NGF, proNGF and p75NTR protein levels were comparable between groups. Bax: Bcl-2 ratio was higher in preterm (p < 0.05) compared to term placenta. p75NTR was positively associated with Bax levels and sortilin levels were positively associated with p75NTR in whole cohort as well as individual groups.

DISCUSSION

The higher Bax: Bcl-2 ratio in preterm placenta suggests the sensitivity to apoptosis. There were no differences in levels of NGF, proNGF, p75NTR, sortilin, and furin between groups. The observed associations between p75NTR, sortilin and Bax suggest that p75NTR and sortilin mediated signalling may be involved in the mechanisms leading to higher apoptosis in preterm placentae.

Neurotrophins: are they involved in immune tolerance in pregnancy?

In this review, an attempt was made to substantiate the possibility for neurotrophins to be involved in the development of immune tolerance based on data accumulated on neurotrophin content and receptor expression in the trophoblast and immune cells, in particular, in natural killer cells. Numerous research results are reviewed to show that the expression and localization of neurotrophins along with their high-affinity tyrosine kinase receptors and low-affinity p75NTR receptor in the mother-placenta-fetus system indicate the important role of neurotrophins as binding molecules in regulating the crosstalk between the nervous, endocrine, and immune systems in pregnancy. An imbalance between these systems can occur with tumor growth and pathological processes observed in pregnancy complications and fetal development anomalies.

Increased levels of nerve growth factor accompany oxidative load in recurrent pregnancy loss. Machine learning applied to FT-Raman spectra study

The presented article is focused on developing and validating an efficient, credible, minimally invasive technique based on spectral signatures of blood serum samples in patients with diagnosed recurrent pregnancy loss (RPL) versus healthy individuals who were followed at the Gynecology department. A total of 120 participants, RPL disease (n = 60) and healthy individuals (n = 60), participated in the study. First, we investigated the effect of circulating nerve growth factor (NGF) in RPL and healthy groups. To show NGF's effect, we measured the level of oxidative loads such as Total Antioxidant Level (TAS), Total Oxidant Level (TOS), and Oxidative Stress Index (OSI) with Beckman Coulter AU system and biochemical assays. We find a correlation between oxidative load and NGF level. Oxidative load mainly causes structural changes in the blood. Therefore, we obtained Raman measurements of the participant's serum. Then we selected two Raman regions, 800 and 1800 cm^-1, and between 2700 cm^-1 and 3000 cm^-1, to see chemical changes. We noted that Raman spectra obtained for RPL and healthy women differed. The findings confirm that the imbalance between reactive oxygen species and antioxidants has important implications for the pathogenesis of RPL and that NGF levels accompany the level of oxidative load in the RPL state. Biomolecular structure and composition were determined using Raman spectroscopy and machine learning methods, and the correlation of these parameters was studied alongside machine learning technologies to advance toward clinical translation. Here we determined and validated the development of instrumentation for the Analysis of RPL patients' serum that can differentiate from control individuals with an accuracy of 100% using the Raman region corresponding to structural changes. Furthermore, this study found a correlation between traditional biochemical parameters and Raman data. This suggests that Raman spectroscopy is a sensitive tool for detecting biochemical changes in serum caused by RPL or other diseases.

Imbalance of Angiogenic and Growth Factors in Placenta in Maternal Hyperhomocysteinemia

Numerous studies have shown that various adverse factors of different nature and action mechanisms have similar negative influence on placental angiogenesis, resulting in insufficiency of placental blood supply. One of the risk factors for pregnancy complications with placental etiology is an increased level of homocysteine in the blood of pregnant women. However, the effect of hyperhomocysteinemia (HHcy) on the development of the placenta and, in particular, on the formation of its vascular network is at present poorly understood. The aim of this work was to study the effect of maternal HHcy on the expression of angiogenic and growth factors (VEGF-A, MMP-2, VEGF-B, BDNF, NGF), as well as their receptors (VEGFR-2, TrkB, p75NTR), in the rat placenta. The effects of HHcy were studied in the morphologically and functionally different maternal and fetal parts of the placenta on the 14th and 20th day of pregnancy. The maternal HHcy caused increase in the levels of oxidative stress and apoptosis markers accompanied by an imbalance of the studied angiogenic and growth factors in the maternal and/or fetal part of the placenta. The influence of maternal HHcy in most cases manifested in a decrease in the protein content (VEGF-A), enzymatic activity (MMP-2), gene expression (VEGFB, NGF, TRKB), and accumulation of precursor form (proBDNF) of the investigated factors. In some cases, the effects of HHcy differed depending on the placental part and stage of development. The influence of maternal HHcy on signaling pathways and processes controlled by the studied angiogenic and growth factors could lead to incomplete development of the placental vasculature and decrease in the placental transport, resulting in fetal growth restriction and impaired fetal brain development.

Study on NGF and VEGF during the Equine Perinatal Period-Part 2: Foals Affected by Neonatal Encephalopathy

Neonatal Encephalopathy (NE) may be caused by hypoxic ischemic insults or inflammatory insults and modified by innate protective or excitatory mechanisms. Understanding the underlying pathophysiology is important in formulating a rational approach to diagnosis. The preliminary aim was to clinically characterize a population of foals spontaneously affected by NE. The study aimed to: (i) evaluate nerve growth factor (NGF) and vascular endothelial growth factor (VEGF) levels in plasma samples obtained in the affected population at parturition from the mare’s jugular vein, umbilical cord vein and foal’s jugular vein, as well as in amniotic fluid; (ii) evaluate the NGF and VEGF content in the plasma of foals affected by NE during the first 72 h of life/hospitalization; (iii) evaluate NGF and VEGF levels at birth/admission in relation to selected mare’s and foal’s clinical parameters; (iv) evaluate the relationship between the two trophic factors and thyroid hormone levels (TT3 and TT4) in the first 72 h of life/hospitalization; and (v) assess the mRNA expression of NGF, VEGF and brain-derived neurotrophic factor (BDNF), and their cell surface receptors, in the placenta of mares that delivered foals affected by NE. Thirteen affected foals born from mares hospitalized for peripartum monitoring (group NE) and twenty affected foals hospitalized after birth (group exNE) were included in the study. Dosage of NGF and VEGF levels was performed using commercial ELISA kits, whereas NGF, VEGF, and BDNF placental gene expression was performed using a semi-quantitative real-time PCR. In group NE, NGF levels decreased significantly from T0 to T24 (p = 0.0447) and VEGF levels decreased significantly from T0 to T72 (p = 0.0234), whereas in group exNE, only NGF levels decreased significantly from T0 to T24 (p = 0.0304). Compared to healthy foals, a significant reduction of TT3 levels was observed in both NE (T24, p = 0.0066; T72 p = 0.0003) and exNE (T0, p = 0.0082; T24, p < 0.0001; T72, p < 0.0001) groups, whereas a significant reduction of TT4 levels was observed only in exNE group (T0, p = 0.0003; T24, p = 0.0010; T72, p = 0.0110). In group NE, NGF levels were positively correlated with both TT3 (p = 0.0475; r = 0.3424) and TT4 levels (p = 0.0063; r = 0.4589). In the placenta, a reduced expression of NGF in the allantois (p = 0.0033) and a reduced expression of BDNF in the amnion (p = 0.0498) were observed. The less pronounced decrease of the two trophic factors compared to healthy foals, their relationship with thyroid hormones over time, and the reduced expression of NGF and BDNF in placental tissues of mares that delivered affected foals, could be key regulators in the mechanisms of equine NE.

Study on NGF and VEGF during the Equine Perinatal Period-Part 1: Healthy Foals Born from Normal Pregnancy and Parturition

The importance of trophic factors, such as nerve growth factor (NGF), vascular endothelial growth factor (VEGF), and brain-derived neurotrophic factor (BDNF) during the perinatal period, is now emerging. Through their functional activities of neurogenesis and angiogenesis, they play a key role in the final maturation of the nervous and vascular systems. The present study aims to: (i) evaluate the NGF and VEGF levels obtained at parturition from the mare, foal and umbilical cord vein plasma, as well as in amniotic fluid; (ii) evaluate NGF and VEGF content in the plasma of healthy foals during the first 72 h of life (T0, T24 and T72); (iii) evaluate NGF and VEGF levels at parturition in relation to the selected mares’ and foals’ clinical parameters; (iv) evaluate the relationship between the two trophic factors and the thyroid hormone levels (TT3 and TT4) in the first 72 h of life; (v) assess mRNA expression of NGF, VEGF and BDNF and their cell surface receptors in the placenta. Fourteen Standardbred healthy foals born from mares with normal pregnancies and parturitions were included in the study. The dosage of NGF and VEGF levels was performed using commercial ELISA kits, whereas NGF, VEGF and BDNF placental gene expression was performed using semi-quantitative real-time PCR. In foal plasma, both NGF and VEGF levels decreased significantly over time, from T0 to T24 (p = 0.0066 for NGF; p < 0.0001 for VEGF) and from T0 to T72 (p = 0.0179 for NGF; p = 0.0016 for VEGF). In foal serum, TT3 levels increased significantly over time from T0 to T24 (p = 0.0058) and from T0 to T72 (p = 0.0013), whereas TT4 levels decreased significantly over time from T0 to T24 (p = 0.0201) and from T0 to T72 (p < 0.0001). A positive correlation was found in the levels of NGF and VEGF in foal plasma at each time point (p = 0.0115; r = 0.2862). A positive correlation was found between NGF levels in the foal plasma at T0 and lactate (p = 0.0359; r = 0.5634) as well as between VEGF levels in the foal plasma at T0 and creatine kinase (p = 0.0459; r = 0.5407). VEGF was expressed in all fetal membranes, whereas NGF and its receptors were not expressed in the amnion. The close relationship between the two trophic factors in foal plasma over time and their fine expression in placental tissues appear to be key regulators of fetal development and adaptation to extra-uterine life.

The balance between cell survival and death in the placenta: Do neurotrophins have a role?

Neurotrophins (NT) are a closely related family of growth factors, which regulate the nervous system's development, maintenance, and function. Although NTs have been well studied in neuronal cells, they are also expressed in the placenta. Despite their suggested role in regulating fetoplacental development, their precise functional significance in the placenta remains elusive. NT activate two different classes of receptors. These include the Trk, tropomyosin-related kinase family of high-affinity tropomyosin-related kinase receptors, which induces cell survival, and the p75NTR, p75 neurotrophin receptor, a member of the tumor necrosis factor(TNF) receptor superfamily, which induces apoptosis in neuronal cells. Mature NT molecule results from proteolysis of a biologically active precursor form called pro-neurotrophins (pro-NT) by the intracellular proprotein convertase or furin. Pro-NTs have a regulatory role in determining cell survival and apoptosis. Here, we review the literature on the expression and functions of NTs and their receptors in the placenta and discuss their possible role in placental tissue development and apoptosis. The possible implications of imbalance in pro-NT and mature-NT levels for fetoplacental development are also discussed.Abbreviations AGE/ALEs: Advanced glycation/lipoxidation end products; Bax: Bcl 2 Associated X; Bcl-2: B-cell lymphoma 2; BDNF: Brain-derived neurotrophic factor; FAS/FASL: Fas cell surface death receptor/ ligand; IUGR: Intrauterine growth restriction; JNK: c-Jun amino-terminal kinase; MAP: mitogen-activated protein k; mRNA: Messenger ribonucleic acid; NGF: Nerve growth factor; NT: Neurotrophins; NRAGE: Neurotrophin receptor-interacting MAGE homolog; NRIF: Neurotrophin receptor interacting factor; PE: Preeclampsia; PI3k: Phosphoinositide 3- kinase; PLC: Phospholipase C; p75NTR: p75 neurotrophin receptor; Pro-NT: Pro-neurotrophins; PTB: Preterm birth; p53: Tumor protein p53; TNF: Tumor necrosis factor; TRAF: TNFR-associated factors; Trk: Tropomyosin-related kinase; siRNA: small interfering ribonucleic acid.

Acceleration of TAA-Induced Liver Fibrosis by Stress Exposure Is Associated with Upregulation of Nerve Growth Factor and Glycopattern Deviations

Liver fibrosis results from many chronic injuries and may often progress to cirrhosis and hepatocellular carcinoma (HCC). In fact, up to 90% of HCC arise in a cirrhotic liver. Conversely, stress is implicated in liver damage, worsening disease outcome. Hence, stress could play a role in disrupting liver homeostasis, a concept that has not been fully explored. Here, in a murine model of TAA-induced liver fibrosis we identified nerve growth factor (NGF) to be a crucial regulator of the stress-induced fibrogenesis signaling pathway as it activates its receptor p75 neurotrophin receptor (p75NTR), increasing liver damage. Additionally, blocking the NGF decreased liver fibrosis whereas treatment with recombinant NGF accelerated the fibrotic process to a similar extent than stress challenge. We further show that the fibrogenesis induced by stress is characterized by specific changes in the hepatoglycocode (increased β1,6GlcNAc-branched complex N-glycans and decreased core 1 O-glycans expression) which are also observed in patients with advanced fibrosis compared to patients with a low level of fibrosis. Our study facilitates an understanding of stress-induced liver injury and identify NGF signaling pathway in early stages of the disease, which contributes to the established fibrogenesis.

Transcriptomics-determined chemokine-cytokine pathway presents a common pathogenic mechanism in pregnancy loss and spontaneous preterm birth

PROBLEM

Various etiological factors, such as infection and inflammation, may induce the adverse outcomes of pregnancy of miscarriage, stillbirth, or preterm birth. The pathogenic mechanisms associated with these adverse pregnancies are yet unclear. We hypothesized that a common pathogenic mechanism may underlie variant adverse outcomes of pregnancy, which are induced by genetic-environmental factors. The specific objective of the current study is to uncover the common molecular mechanism(s) by identifying the specific transcripts that are present in variant subtypes of pregnancy loss and preterm birth.

METHOD OF STUDY

Transcriptomic profiling was performed with RNA expression microarray or RNA sequencing of placentas derived from pregnancy loss (which includes spontaneous miscarriage, recurrent miscarriage, and stillbirth) and spontaneous preterm birth, followed by bioinformatic analysis of multi-omic integration to identify pathogenic molecules and pathways involved in pathological pregnancies.

RESULTS

The enrichment of common differentially expressed genes between full-term birth and preterm birth and pregnancy loss of miscarriage and stillbirth revealed different pathophysiological pathway(s), including cytokine signaling dysregulated in spontaneous preterm birth, defense response, graft-versus-host disease, antigen processing and presentation, and T help cell differentiation in spontaneous miscarriage. Thirty-three genes shared between spontaneous preterm birth and spontaneous miscarriage were engaged in pathways of interferon gamma-mediated signaling and of antigen processing and presentation. For spontaneous miscarriage, immune response was enriched in the fetal tissue of chorionic villi and in the maternal facet of the placental sac. The transcript of nerve growth factor receptor was identified as the common molecule that is differentially expressed in all adverse pregnancies: spontaneous preterm birth, stillbirth, spontaneous miscarriage, and recurrent miscarriage. Superoxide dismutase 2 was up-regulated in all adverse outcomes of pregnancy except for recurrent miscarriage. Cytokine-cytokine receptor interaction was the common pathway in spontaneous preterm birth and spontaneous miscarriage. Defense response was enriched in the fetal tissue of miscarriage and in the maternal tissue in spontaneous miscarriage.

CONCLUSIONS

Our results indicated that the chemokine-cytokine pathway may play important roles in and function as a common pathogenic mechanism associated with, the different adverse outcomes of pregnancy, which demonstrated that differentially expressed transcripts could result from a common pathogenic mechanism associated with pregnancy loss and spontaneous preterm birth, although individual pregnancy outcomes may differ from each other phenotypically.

New Insights Into the Role of β-NGF/TrKA System in the Endometrium of Alpacas During Early Pregnancy

One striking reproductive feature in South American camelids is that more than 90% of gestations are established in the left uterine horn (LUH). This phenomenon could be related to a differential vascular irrigation of the LUH. An increase of vascularization in llama endometrium was observed after systemic administration of Beta Nerve Growth Factor (β-NGF), a neurotrophin present in the uterus and placenta of various mammals that is involved in pregnancy development. We hypothesized that the β-NGF signaling pathway is related to embryo implantation in the LUH in camelids. The aim of this study was to characterize the spatial expression of β-NGF and its high-affinity receptor, TrKA, between LUH and right uterine horn (RUH) of non-pregnant (NP) and early pregnant alpacas (15 and 30 days of gestation, 15 and 30P, respectively). In addition, β-NGF, TrKA, and Vascular Endothelium Growth Factor A (VEGFA) temporal gene expression patterns and counting of blood vessels were evaluated among groups. The β-NGF and TrKA were localized in the luminal, glandular, and vascular epithelium of the alpaca uterus and in the embryonic membranes of the 30-days-old conceptus. β-NGF and TrKA immunosignal were stronger in 15P females than that of NP and 30P. In addition, TrKA signal was higher in the LUH luminal epithelium of NP and 15P alpacas than that of NP-RUH and 15P-RUH. β-NGF mRNA relative abundance was higher in the 30P-RUH than that of NP-RUH; whereas TrKA mRNA abundance only differed between 15P-RUH and NP-LUH. VEGFA mRNA relative abundance was higher in NP females compared to the LUH of 15P and 30P alpacas, and lower to their right counterparts. The number of vessels per field was higher in 15P than that of 30P. A positive correlation was observed between the number of vessels per field and β-NGF immunosignal in 15P-LUH. In contrast, the area occupied by vessels was higher in 30P alpacas than of NP and 15P females. The changes of β-NGF/TrKA expression pattern in the peri-implantation endometria between LUH and RUH and their localization in the extraembryonic membranes support the implication of the neurotrophin during implantation and pregnancy development in South American Camelids.

Nerve growth factor is closely related to glucose metabolism, insulin sensitivity and insulin secretion in the second trimester: a case-control study in Chinese

Objective

Inflammation-related factors have been shown to play a significant role throughout pregnancy. In this study, we aimed to explore the relationships between selected inflammatory cytokines and gestational diabetes (GDM) in Chinese pregnant women.

Design and methods

This was a 1:1 matched case–control study that included 200 pairs of subjects in the second trimester and 130 pairs of subjects in the third trimester. Serum levels of nerve growth factor (NGF), Interleukin-6 (IL-6), leptin, Interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α) and Interleukin-1beta (IL-1β) were measured by enzyme immunoassay. The associations of these inflammatory factors with metabolic parameters were analysed.

Results

In the second trimester, GDM patients had higher NGF levels and lower IL-8 levels than did normal controls (P < 0.001 and P = 0.015, respectively). However, in the third trimester, only lower leptin levels were observed in the GDM group (P = 0.031). Additionally, in the second trimester, NGF levels were not only positively associated with fasting, 1-h and 2-h glucose levels and the area under curve of glucose, but also positively related to insulin sensitivity and secretion, as suggested by fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment index of β-cell secretion (HOMA-β) (all P < 0.05). Moreover, IL-6 and leptin levels were positively correlated with HOMA-IR and HOMA-β, and TNF-α levels were positively related to HOMA-IR (all P < 0.05). Except for the relationships between NGF and HOMA-β and TNF-α and HOMA-IR, the other correlations still existed even after adjusting for confounding factors (all P < 0.05).

Conclusion

In addition to the positive associations of IL-6 and leptin with insulin resistance and secretion, NGF was higher in the GDM patients and strongly linked to glucose metabolism, insulin resistance and pancreatic β cell function in Chinese pregnant women in the second trimester.

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.

Parity Attenuates Intraepithelial Corneal Sensory Nerve Loss in Female Mice

Aging impacts the ocular surface and reduces intraepithelial corneal nerve (ICN) density in male and female mice. Many researchers use retired breeders to study naturally aged female mice. Yet, the impact of parity and the length of time since breeders were retired on age-related changes in the intraepithelial corneal nerves is not known. Here we study 2 month (M) nulliparous (NP) females as well as 9M, 10M, and 11M NP and multiparous (MP) female mice to determine whether parity impacts the age-related decline seen in corneal axon density; 9M male mice are also included in these assessments. After showing that parity attenuates age-related loss in axon density, we also assess the impact of parity on corneal epithelial cell proliferation and find that it impacts cell proliferation and axon density normalized by cell proliferation. Stromal nerve arborization is also impacted by aging with parity enhancing stromal nerves in older mice. qPCR was performed on 20 genes implicated in ICN density using corneal epithelial RNA isolated from 10M NP and MP mice and showed that NGF expression was significantly elevated in MP corneal epithelium. Corneal sensitivity was significantly higher in 9M MP mice compared to NP mice and increased sensitivity in MP mice was accompanied by increased nerve terminals in the apical and middle cell layers. Together, these data show that parity in mice attenuates several aspects of the age-related decline seen on the ocular surface by retaining sensory axons and corneal sensitivity as mice age.

Potent and rapid activation of tropomyosin-receptor kinase A in endometrial stromal fibroblasts by seminal plasma

Seminal plasma (SP), the liquid fraction of semen, is not mandatory for conception, but clinical studies suggest that SP improves implantation rates. Prior in vitro studies examining the effects of SP on the endometrium, the site of implantation, surprisingly revealed that SP induces transcriptional profiles associated with neurogenesis. We investigated the presence and activity of neurogenesis pathways in the endometrium, focusing on TrkA, one of the canonical receptors associated with neurotrophic signaling. We demonstrate that TrkA is expressed in the endometrium. To determine if SP activates TrkA signaling, we isolated the two most abundant endometrial cell types-endometrial epithelial cells (eEC) and endometrial stromal fibroblasts (eSF)-and examined TrkA activity in these cells after SP exposure. While SP only moderately activated TrkA in eEC, it potently and rapidly activated TrkA in eSF. This activation occurred in both non-decidualized and decidualized eSF. Blocking this pathway resulted in dysregulation of SP-induced cytokine production by eSF. Surprisingly, while the canonical TrkA agonist nerve growth factor was detected in SP, TrkA activation was principally induced by a 30-100-kDa protein whose identity remains to be established. Our results show that TrkA signaling is highly active in eSF and is rapidly induced by SP.

Angiogenesis in Gynecological Cancers: Role of Neurotrophins

Angiogenesis, or generation of new blood vessels from other pre-existing, is a key process to maintain the supply of nutrients and oxygen in tissues. Unfortunately, this process is exacerbated in pathologies such as retinopathies and cancers with high angiogenesis as ovarian cancer. Angiogenesis is regulated by multiple systems including growth factors and neurotrophins. One of the most studied angiogenic growth factors is the vascular endothelial growth factor (VEGF), which is overexpressed in several cancers. It has been recently described that neurotrophins could regulate angiogenesis through direct and indirect mechanisms. Neurotrophins are a family of proteins that include nerve growth factor (NGF), brain-derived growth factor (BDNF), and neurotrophins 3 and 4/5 (NT 3, NT 4/5). These molecules and their high affinity receptors (TRKs) regulate the development, maintenance, and plasticity of the nervous system. Furthermore, it was recently described that they display essential functions in non-neuronal tissues, such as reproductive organs among others. Studies have shown that several types of cancer overexpress neurotrophins such as NGF and BDNF, which might contribute to tumor progression and angiogenesis. Besides, in recent years the FDA has approved the use of pharmacologic inhibitors of pan-TRK receptors in patients with TRKs fusion-positive cancers. In this review, we discuss the mechanisms by which neurotrophins stimulate tumor progression and angiogenesis, with emphasis on gynecological cancers.

Differential Expression of Nerve Growth Factor (NGF) and Brain Derived Neurotrophic Factor (BDNF) in Different Regions of Normal and Preeclampsia Placentae

Background: Our recent study indicates differential protein levels of neurotrophins and angiogenic factors in various regions of the normotensive and preeclampsia (PE) placenta. These changes may be in a response to differential mRNA expression of neurotrophins.Methods: This study examines the mRNA levels of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) in different regions of the placenta in normotensive control (NC) women and women with PE. Thirty NC women and forty one women with PE (18 delivered at term [T-PE] and 23 delivered preterm [PT-PE]) were included in the study. Placental samples were taken from four regions: central basal (CM), central chorionic (CF), peripheral basal (PM), and peripheral chorionic (PF). The mRNA levels of neurotrophins were measured by quantitative real-time PCR.Results: The BDNF mRNA levels were higher in peripheral fetal region as compared to peripheral basal region in NC (p < 0.05) group, PE group (p < 0.05) and term PE group (p < 0.01). The BDNF mRNA levels were lower in the central basal region of preterm PE group (p < 0.05) as compared to the NC group.Conclusion: The present study indicates that NGF and BDNF are expressed differentially across various regions of the placenta. This has implications for selection of the sampling site in the placenta while carrying out placental studies.

Obstetric outcomes in pregnant women with and without depression: population-based comparison

This study used insurance claims data to evaluate obstetric outcomes in pregnant women with and without depression because population study for Asian women on the issue is limited. We identified 5,064 women with depression at pregnancy in 2005–2013, and 20,024 pregnant women without depression, frequency matched by age, pregnant year and parity. Obstetric events during pregnancy and deliveries were evaluated. The depression group had more events than comparisons for hyperemesis (39.3 vs. 35.5%), abortion (3.3 vs. 2.6%), malpresentation (12.3 vs. 10.3%), C-section (40.2 vs. 34.6%) and intrauterine fetal demise (0.7 vs. 0.4%); risks of these events were significant for childbearing depressed women, not for the 35+ years subgroup. These incidences were higher in depressed women taking antidepressant than those without the medication, but were significant in childbearing depressed subgroup for hyperemesis and C-section with odds ratios of 1.18 (95% confidence intervals (CI), 1.02–1.36) and 1.29 (95% CI, 1.11–1.49), respectively. Incident preterm and low birth weight births were also higher in the depression group than in comparisons, but weren’t significant. In conclusion, women with depression during pregnancy may develop more adverse events than comparisons and are more likely to have a C-section delivery.

VEGF and VEGFR1 levels in different regions of the normal and preeclampsia placentae

Altered placental angiogenesis is implicated in the pathophysiology of preeclampsia. We have earlier reported placental regional differences in oxidative stress markers and neurotrophins. Oxidative stress and neurotrophins are reported to regulate angiogenesis. This study aims to examine protein and mRNA levels of vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1) in four regions [central maternal (CM), central fetal (CF), peripheral maternal (PM), and peripheral fetal (PF)] of the placenta in normotensive control (NC) women (n = 51) and women with preeclampsia (PE) (n = 43) [18 delivered at term (T-PE) and 25 delivered preterm (PT-PE)]. In all groups, CF region reported highest VEGF protein levels compared to all other regions. VEGF mRNA level was higher in CF region as compared to CM region in PE group (p < 0.05). VEGF levels were lower in all regions of PE, T-PE, and PT-PE groups (p < 0.05) as compared to their respective regions in NC group. VEGFR1 levels were lower in CF (p < 0.05) and PF (p < 0.01) regions as compared to CM region only in control. However, VEGFR1 levels were higher in CF (p < 0.05) and PF (p < 0.01) regions of PT-PE group as compared to control. VEGFR1 mRNA level was higher in PM region of PE group and T-PE group (p < 0.05 for both) as compared to control. VEGF levels in the PF region were positively associated with birth weight and placental weight. This study describes placental regional changes in angiogenic factors particularly highlighting increased VEGF in CF region possibly in response to hypoxic conditions prevailing in placenta.

Maternal testosterone and placental function: Effect of electroacupuncture on placental expression of angiogenic markers and fetal growth

Women with polycystic ovary syndrome (PCOS) have elevated circulating androgens during pregnancy and are at an increased risk of adverse pregnancy outcomes. Here we tested the hypotheses that maternal androgen excess decrease placental and fetal growth, and placental expression of markers of steroidogenesis, angiogenesis and sympathetic activity, and that acupuncture with low-frequency electrical stimulation prevents these changes. Pregnant rats were exposed to vehicle or testosterone on gestational day (GD)15-19. Low-frequency electroacupuncture (EA) or handling, as a control for the EA procedure, was given to control or testosterone exposed dams on GD16-20. On GD21, blood pressure was measured and maternal blood, fetuses and placentas collected. Placental steroid receptor expression and proteins involved in angiogenic, neurotrophic and adrenergic signaling were analyzed. EA did not affect any variables in control rats except maternal serum corticosterone, which was reduced. EA in testosterone exposed dams compared with controls increased systolic pressure by 30%, decreased circulating norepinephrine and corticosterone, fetal and placental weight and placental VEGFR1 and proNGF protein expression, and increased the VEGFA/VEGFR1 ratio, mature NGF (mNGF) and the mNGF/proNGF ratio. In conclusion, low-frequency EA in control animals did not have any negative influence on any of the studied variables. In contrast, EA in pregnant dams exposed to testosterone increased blood pressure and impaired placental growth and function, leading to decreased fetal growth.

Expression of nerve growth factor and its receptors in the uterus of rabbits: functional involvement in prostaglandin synthesis

The aim of the present study was to evaluate: (1) the presence of nerve growth factor (NGF), neurotrophic tyrosine kinase receptor 1 (NTRK1), and nerve growth factor receptor (NGFR) in the rabbit uterus; and (2) the in vitro effects of NGF on PGF2α and PGE2 synthesis and on the PGE2-9-ketoreductase (PGE2-9-K) activity by the rabbit uterus. Nerve growth factor, NTRK1, and NGFR were immunolocalized in the luminal and glandular epithelium and stroma cells of the endometrium. reverse transcriptase polymerase chain reaction indicated the presence of messenger RNA for NGF, NTRK1, and NGFR in the uterus. Nerve growth factor increased (P < 0.01) in vitro secretions of PGF2α and PGE2 but coincubation with either NTRK1 or oxide nitric synthase (NOS) inhibitors reduced (P < 0.01) PGF2α production and blocked (P < 0.01) PGE2 secretion. Prostaglandins releases were lower (P < 0.01) than control when uterine samples were treated with NGF plus cyclooxygenase inhibitor. However, addition of NGFR inhibitor reduced (P < 0.01) PGF2α secretion less efficiently than NTRK1 or NOS inhibitors but had no effect on PGE2 yield. Nerve growth factor increased (P < 0.01) the activity of PGE2-9-K, whereas coincubation with NTRK1 or NOS inhibitors abolished (P < 0.01) this increase in PGE2-9-K activity. However, cotreatment with either cyclooxygenase or NGFR inhibitors had no effect on PGE2-9-K activity. This is the first study to document the distribution of NGF/NTRK1 and NGFR systems and their effects on prostaglandin synthesis in the rabbit uterus. NGF/NTRK1 increases PGF2α and PGE2 productions by upregulating NOS and PGE2-9-K activities, whereas NGF/NGFR augments only PGF2α secretion, through an intracellular mechanism that is still unknown.

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.

Neurotrophin levels in different regions of the placenta and their association with birth outcome and blood pressure

INTRODUCTION

Our recent study in preeclampsia indicates differential oxidative stress in various regions of the placenta. Oxidative stress is known to influence neurotrophin levels. We therefore hypothesize that placental regional differences in oxidative stress will also lead to differences in neurotrophin levels.

METHODS

The current study examines the levels of neurotrophins, brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in different regions of the placenta in 50 normotensive control women and 47 women with preeclampsia (21 delivering at term and 26 delivering preterm). Placentae were collected from four different regions: central maternal (CM), central fetal (CF), peripheral maternal (PM) and peripheral fetal (PF).

RESULTS

BDNF levels were higher in CF region as compared to CM (p < 0.01), PM (p < 0.01) and PF (p < 0.05) regions of the placenta in the control group. There was no regional change in NGF levels in any of the groups. Analysis between groups indicated higher NGF levels in CM (p < 0.01), PM (p < 0.05) and PF (p < 0.01) regions of preterm preeclampsia group as compared to control. Negative association of NGF levels in CM, CF and PM regions with baby weight and in CF, PM and PF regions with baby length was observed. NGF levels in all four regions were positively associated with systolic blood pressure.

DISCUSSION

Our data indicates regional differences in levels of BDNF only in normotensive control but not in preeclampsia group. Higher NGF levels in preterm preeclampsia may be a response to increased oxidative stress. This may have implications for altered placental development in preeclampsia.

The effect of antenatal depression and selective serotonin reuptake inhibitor treatment on nerve growth factor signaling in human placenta

Depressive symptoms during pregnancy are common and may have impact on the developing child. Selective serotonin reuptake inhibitors (SSRIs) are the most prescribed antidepressant treatment, but unfortunately, these treatments can also negatively affect the behavioral development and health of a child during pregnancy. In addition, serotonin (5-HT) exerts neurotrophic actions with thus far not fully known effects in the offspring. The neurotrophic growth factor (NGF) is involved in neuronal cell survival and differentiation, and altered placenta levels have been found to increase the risk for pregnancy complications, similar to those found in women treated with SSRIs. We therefore investigated whether the NGF signaling pathway was altered in the placenta from women treated with SSRIs (n = 12) and compared them with placenta from depressed (n = 12) and healthy mothers (n = 12). Results from immunohistochemical stainings revealed that placental NGF protein levels of SSRI-treated women were increased in both trophoblasts and endothelial cells compared with depressed and control women. In addition, downstream of the NGF receptor TrkA, increased levels of the signaling proteins ROCK2 and phosphorylated Raf-1 were found in stromal cells and a tendency towards increased levels of ROCK2 in trophoblasts and endothelial cells in SSRI-treated women when compared to healthy controls. SSRI-treated women also displayed increased levels of phosphorylated ROCK2 in all placental cell types studied in comparison with depressed and control women. Interestingly, in placental endothelial cells from depressed women, NGF levels were significantly lower compared to control women, but ROCK2 levels were increased compared with control and SSRI-treated women. Taken together, these results show that the NGF signaling and downstream pathways in the placenta are affected by SSRI treatment and/or antenatal depression. This might lead to an altered placental function, although the clinical relevance of our findings still needs to be investigated.