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American Journal of Obstetrics and... Mar 2024Oxytocin is a reproductive hormone implicated in the process of parturition and widely used during labor. Oxytocin is produced within the supraoptic nucleus and... (Review)
Review
Oxytocin is a reproductive hormone implicated in the process of parturition and widely used during labor. Oxytocin is produced within the supraoptic nucleus and paraventricular nucleus of the hypothalamus and released from the posterior pituitary lobe into the circulation. Oxytocin is released in pulses with increasing frequency and amplitude in the first and second stages of labor, with a few pulses released in the third stage of labor. During labor, the fetus exerts pressure on the cervix of the uterus, which activates a feedforward reflex-the Ferguson reflex-which releases oxytocin. When myometrial contractions activate sympathetic nerves, it decreases oxytocin release. When oxytocin binds to specific myometrial oxytocin receptors, it induces myometrial contractions. High levels of circulating estrogen at term make the receptors more sensitive. In addition, oxytocin stimulates prostaglandin synthesis and release in the decidua and chorioamniotic membranes by activating a specific type of oxytocin receptor. Prostaglandins contribute to cervical ripening and uterine contractility in labor. The oxytocin system in the brain has been implicated in decreasing maternal levels of fear, pain, and stress, and oxytocin release and function during labor are stimulated by a social support. Moreover, studies suggest, but have not yet proven, that labor may be associated with long-term, behavioral and physiological adaptations in the mother and infant, possibly involving epigenetic modulation of oxytocin production and release and the oxytocin receptor. In addition, infusions of synthetic oxytocin are used to induce and augment labor. Oxytocin may be administered according to different dose regimens at increasing rates from 1 to 3 mIU/min to a maximal rate of 36 mIU/min at 15- to 40-minute intervals. The total amount of synthetic oxytocin given during labor can be 5 to 10 IU, but lower and higher amounts of oxytocin may also be given. High-dose infusions of oxytocin may shorten the duration of labor by up to 2 hours compared with no infusion of oxytocin; however, it does not lower the frequency of cesarean delivery. When synthetic oxytocin is administered, the plasma concentration of oxytocin increases in a dose-dependent way: at infusion rates of 20 to 30 mIU/min, plasma oxytocin concentration increases approximately 2- to 3-fold above the basal level. Synthetic oxytocin administered at recommended dose levels is not likely to cross the placenta or maternal blood-brain barrier. Synthetic oxytocin should be administered with caution as high levels may induce tachystole and uterine overstimulation, with potentially negative consequences for the fetus and possibly the mother. Of note, 5 to 10 IU of synthetic oxytocin is often routinely given as an intravenous or intramuscular bolus administration after delivery to induce uterine contractility, which, in turn, induces uterine separation of the placenta and prevents postpartum hemorrhage. Furthermore, it promotes the expulsion of the placenta.
Topics: Pregnancy; Female; Humans; Oxytocin; Receptors, Oxytocin; Peripartum Period; Labor, Obstetric; Oxytocics; Labor, Induced
PubMed: 38462255
DOI: 10.1016/j.ajog.2023.04.011 -
Scientific Reports Mar 2024The involvement of Ca ions in angiosperms sexual processes is well established, while in gymnosperms, such knowledge remains limited and is still a topic of discussion....
The involvement of Ca ions in angiosperms sexual processes is well established, while in gymnosperms, such knowledge remains limited and is still a topic of discussion. In this study, we focused on Larix decidua, using Alizarin-red S staining and the pyroantimonate method to examine the tissue and subcellular distribution of free and loosely bound Ca ions at different stages of the male gametophyte's development and its interaction with the ovule. Our findings show that in larch, both the germination of pollen grains and the growth of pollen tubes occur in an environment rich in Ca. These ions play a crucial role in the adhesion of the pollen grain to the stigmatic tip and its subsequent movement to the micropylar canal. There is a significant presence of free and loosely bound Ca ions in both the fluid of the micropylar canal and the extracellular matrix of the nucellus. As the pollen tube extends through the nucellus, we observed a notable accumulation of Ca ions just above the entry to the mature archegonium, a region likely crucial for the male gametophyte's directional growth. Meanwhile, the localized presence of free and loosely bound Ca ions within the egg cell cytoplasm may inhibit the pollen tubes growth and rupture, playing an important role in fertilization.
Topics: Pollination; Larix; Pollen Tube; Pollen; Ions; Germination
PubMed: 38454044
DOI: 10.1038/s41598-024-54903-2 -
Cell Death Discovery Feb 2024Regulated cell death (RCD) plays a fundamental role in placental development and tissue homeostasis. Placental development relies upon effective implantation and... (Review)
Review
Regulated cell death (RCD) plays a fundamental role in placental development and tissue homeostasis. Placental development relies upon effective implantation and invasion of the maternal decidua by the trophoblast and an immune tolerant environment maintained by various cells at the maternal-fetal interface. Although cell death in the placenta can affect fetal development and even cause pregnancy-related diseases, accumulating evidence has revealed that several regulated cell death were found at the maternal-fetal interface under physiological or pathological conditions, the exact types of cell death and the precise molecular mechanisms remain elusive. In this review, we summarized the apoptosis, necroptosis and autophagy play both promoting and inhibiting roles in the differentiation, invasion of trophoblast, remodeling of the uterine spiral artery and decidualization, whereas ferroptosis and pyroptosis have adverse effects. RCD serves as a mode of communication between different cells to better maintain the maternal-fetal interface microenvironment. Maintaining the balance of RCD at the maternal-fetal interface is of utmost importance for the development of the placenta, establishment of an immune microenvironment, and prevention of pregnancy disorders. In addition, we also revealed an association between abnormal expression of key molecules in different types of RCD and pregnancy-related diseases, which may yield significant insights into the pathogenesis and treatment of pregnancy-related complications.
PubMed: 38409106
DOI: 10.1038/s41420-024-01867-x -
Journal of Advanced Research Feb 2024Advanced maternal age is associated with reduced implantation and pregnancy rates, yet the underlying mechanisms remain poorly understood, and research models are...
INTRODUCTION
Advanced maternal age is associated with reduced implantation and pregnancy rates, yet the underlying mechanisms remain poorly understood, and research models are limited.
OBJECTIVES
Here, we aim to elucidate the impacts of senescence on implantation ability by employing blastoids to construct a novel research model.
METHODS
We used a novel three-dimensional system with totipotent blastomere-like cells (TBLCs) to construct TBL-blastoids and established senescence-related embryo models derived from oxidative stress-induced TBLCs.
RESULTS
Morphological and transcriptomic analyses revealed that TBL-blastoids exhibited characteristic blastocyst morphology, cell lineages, and a higher consistency in developmental rate. TBL-blastoids demonstrated the ability to develop into postimplantation structures in vitro and successfully implanted into mouse uteri, inducing decidualization and forming embryonic tissues. Importantly, senescence impaired the implantation potential of TBL-blastoids, effectively mimicking the impaired implantation ability and reduced pregnancy rates associated with advanced age. Furthermore, analysis of differentially expressed genes (DEGs) in human homologous deciduae revealed enrichment in multiple fertility-related diseases and other complications of pregnancy. The genes implicated in these diseases and the common DEGs identified in the lineage-like cells of the two types of TBL-blastoids and deciduae may represent potential targets for addressing impaired implantation potential.
CONCLUSION
These results unveiled that TBL blastoids are an improved model for investigating implantation and early postimplantation, offering valuable insights into pregnancy-related disorders in women with advanced age and potential targets for therapeutic interventions.
PubMed: 38402947
DOI: 10.1016/j.jare.2024.02.011 -
Communications Biology Feb 2024Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered...
Endometriosis is linked to increased infertility and pregnancy complications due to defective endometrial decidualization. We hypothesized that identification of altered signaling pathways during decidualization could identify the underlying cause of infertility and pregnancy complications. Our study reveals that transforming growth factor β (TGFβ) pathways are impaired in the endometrium of individuals with endometriosis, leading to defective decidualization. Through detailed transcriptomic analyses, we discovered abnormalities in TGFβ signaling pathways and key regulators, such as SMAD4, in the endometrium of affected individuals. We also observed compromised activity of bone morphogenetic proteins (BMP), a subset of the TGFβ family, that control endometrial receptivity. Using 3-dimensional models of endometrial stromal and epithelial assembloids, we showed that exogenous BMP2 improved decidual marker expression in individuals with endometriosis. Our findings reveal dysfunction of BMP/SMAD signaling in the endometrium of individuals with endometriosis, explaining decidualization defects and subsequent pregnancy complications in these individuals.
Topics: Pregnancy; Female; Humans; Endometriosis; Decidua; Bone Morphogenetic Proteins; Transforming Growth Factor beta; Signal Transduction; Infertility; Pregnancy Complications
PubMed: 38402336
DOI: 10.1038/s42003-024-05898-z -
Drug Discoveries & Therapeutics Mar 2024Maintenance of pregnancy is highly dependent on the maternal immune system. High levels of regulatory T cells (Tregs) accumulate in the maternal placenta to suppress...
Maintenance of pregnancy is highly dependent on the maternal immune system. High levels of regulatory T cells (Tregs) accumulate in the maternal placenta to suppress immunoreactivity against fetal antigens. We assessed whether Astragalus root (AsR) and AsR-containing Kampo medicines modulate immunoreactivity and thereby increase mouse litter size. AsR-exposed murine splenocytes exhibited significantly increased IL-2 secretion. In AsR-exposed mice, total Tregs were significantly increased, whereas cytotoxic T lymphocyte antigen 4 (CTLA-4)-positive Tregs were decreased in AsR-exposed mice. Tregs express IL-2 receptor subunit alpha and are activated by IL-2. CTLA-4 interacts with B7 expressed in antigen-presenting cells (APCs) with high affinity, and CTLA-4/B7 signaling plays a critical role in inhibiting APC activity, thereby suppressing CD4 T cell proliferation and activation. The decrease in CTLA-4 Tregs in AsR-exposed mice is thought to induce an increase in CD4 T cells, leading to increased IL-2 secretion from CD4 T cells followed by Treg activation. Th17 cells prevent trophoblast apoptosis, resulting in trophoblast invasion into the decidua. AsR increases Th17 cells, thereby inducing dose-dependent increases in litter size. Although Keishikaogito (KO)- and Ogikenchuto (OK)-exposed mice exhibited increased IL-2 secretion and splenic Tregs, KO also increased CTLA-4 Tregs. Therefore, KO promoted immunosuppression by increasing CTLA-4 Tregs, which induced a decrease in Th17 and exerted little effect on litter size. Therefore, an increase in both Tregs and Th17 cells can be considered necessary for embryo implantation and pregnancy maintenance.
Topics: Pregnancy; Female; Mice; Animals; T-Lymphocytes, Regulatory; CTLA-4 Antigen; Interleukin-2; Th17 Cells; Embryo Implantation; Pregnancy Maintenance
PubMed: 38382992
DOI: 10.5582/ddt.2023.01100 -
Frontiers in Immunology 2024Gestational diabetes mellitus (GDM) is a gestational disorder characterized by hyperglycemia, that can lead to dysfunction of diverse cells in the body, especially the...
Gestational diabetes mellitus (GDM) is a gestational disorder characterized by hyperglycemia, that can lead to dysfunction of diverse cells in the body, especially the immune cells. It has been reported that immune cells, specifically natural killer (NK) cells, play a crucial role in normal pregnancy. However, it remains unknown how hyperglycemia affects NK cell dysfunction thus participates in the development of GDM. In this experiment, GDM mice were induced by an intraperitoneal injection of streptozotocin (STZ) after pregnancy and it has been found that the intrauterine growth restriction occurred in mice with STZ-induced GDM, accompanied by the changed proportion and function of NK cells. The percentage of cytotoxic CD27CD11b NK cells was significantly increased, while the proportion of nourished CD27CD11b NK cells was significantly reduced in the decidua of GDM mice. Likewise, the same trend appeared in the peripheral blood NK cell subsets of GDM patients. What's more, after intrauterine reinfusion of NK cells to GDM mice, the fetal growth restriction was alleviated and the proportion of NK cells was restored. Our findings provide a theoretical and experimental basis for further exploring the pathogenesis of GDM.
Topics: Humans; Pregnancy; Female; Mice; Animals; Diabetes, Gestational; Fetal Growth Retardation; Killer Cells, Natural; Diabetes Mellitus, Experimental; Hyperglycemia
PubMed: 38375483
DOI: 10.3389/fimmu.2024.1346231 -
Medicine International 2024Subchorionic hematoma (SCH) is a hematoma in which blood accumulates between the chorion and decidua basalis due to the separation of the chorion and decidua basalis. It... (Review)
Review
Subchorionic hematoma (SCH) is a hematoma in which blood accumulates between the chorion and decidua basalis due to the separation of the chorion and decidua basalis. It is common in patients with threatened abortion in early pregnancy and is mainly detected by ultrasound. SCH mainly manifests as an hypoechoic or anechoic crescent-shaped fluid dark area on ultrasound images. Although there are numerous studies on SCH, its pathogenesis and etiology remain unclear, and its influence on pregnancy outcomes is also controversial; there are also no uniform clinical treatment guidelines. Current studies suggest that the occurrence of SCH may be related to several factors, such as abnormal coagulation function, autoimmune factors of pregnant women, assisted reproduction, drug use during pregnancy and reproductive tract infection; however, its exact etiology remains unclear. Some studies suggest that SCH is associated with adverse pregnancy outcomes such as miscarriage, preterm birth, preeclampsia and fetal growth restriction, although other studies have found that SCH does not increase the risk of adverse pregnancy outcomes. Therefore, the present review mainly discusses the pathogenesis, etiology and treatment of SCH in an aim to provide a reference for the clinical treatment of this condition in pregnant women.
PubMed: 38362561
DOI: 10.3892/mi.2024.134 -
Nature Communications Feb 2024During human pregnancy, extravillous trophoblasts play crucial roles in placental invasion into the maternal decidua and spiral artery remodeling. However, regulatory...
During human pregnancy, extravillous trophoblasts play crucial roles in placental invasion into the maternal decidua and spiral artery remodeling. However, regulatory factors and their action mechanisms modulating human extravillous trophoblast specification have been unknown. By analyzing dynamic changes in transcriptome and enhancer profile during human trophoblast stem cell to extravillous trophoblast differentiation, we define stage-specific regulators, including an early-stage transcription factor, TFAP2C, and multiple late-stage transcription factors. Loss-of-function studies confirm the requirement of all transcription factors identified for adequate differentiation, and we reveal that the dynamic changes in the levels of TFAP2C are essential. Notably, TFAP2C pre-occupies the regulatory elements of the inactive extravillous trophoblast-active genes during the early stage of differentiation, and the late-stage transcription factors directly activate extravillous trophoblast-active genes, including themselves as differentiation further progresses, suggesting sequential actions of transcription factors assuring differentiation. Our results reveal stage-specific transcription factors and their inter-connected regulatory mechanisms modulating extravillous trophoblast differentiation, providing a framework for understanding early human placentation and placenta-related complications.
Topics: Pregnancy; Humans; Female; Placenta; Extravillous Trophoblasts; Trophoblasts; Cell Differentiation; Transcription Factors; Stem Cells
PubMed: 38346993
DOI: 10.1038/s41467-024-45669-2 -
Clinical and Translational Medicine Feb 2024Defective decidualization of endometrial stromal cells (ESCs) in endometriosis (EM) patients leads to inadequate endometrial receptivity and EM-associated infertility....
Defective decidualization of endometrial stromal cells (ESCs) in endometriosis (EM) patients leads to inadequate endometrial receptivity and EM-associated infertility. Hypoxia is an inevitable pathological process of EM and participates in deficient decidualization of the eutopic secretory endometrium. Enhancer of zeste homology 2 (EZH2) is a methyltransferase which catalyses H3K27Me3, leading to decreased expression levels of target genes. Although EZH2 expression is low under normal decidualization, it is abundantly increased in the eutopic secretory endometrium of EM and is induced by hypoxia. Chromatin immunoprecipitation-PCR results revealed that decidua marker IGFBP1 is a direct target of EZH2, partially explaining the increased levels of histone methylation modification in defected decidualization of EM. To mechanism controlling this, we examined the effects of hypoxia on EZH2 and decidualization. EZH2 mRNA showed decreased m A modification and increased expression levels under hypoxia and decidualization combined treatment. Increased EZH2 expression was due to the increased expression of m A demethylase ALKBH5 and decreased expression of the m A reader protein YTHDF2. YTHDF2 directly bind to the m A modification site of EZH2 to promote EZH2 mRNA degradation in ESCs. Moreover, selective Ezh2 depletion in mouse ESCs increased endometrial receptivity and improved mouse fertility by up-regulating decidua marker IGFBP1 expression. This is the first report showing that YTHDF2 can act as a m A reader to promote decidualization by decreasing the stability of EZH2 mRNA and further increasing the expression of IGFBP1 in ESCs. Taken together, our findings highlight the critical role of EZH2/H3K27Me3 in decidualization and reveal a novel epigenetic mechanism by which hypoxia can suppress EM decidualization by decreasing the m A modification of EZH2 mRNA.
Topics: Female; Humans; Animals; Mice; Endometriosis; Histones; RNA; Infertility; Transcription Factors; RNA, Messenger; Methylation; Hypoxia
PubMed: 38344897
DOI: 10.1002/ctm2.1564