The great obstetric syndromes: The roots of disease
Moshe Hod, Lois G. Jovanovic, Gian Carlo Di Renzo, Alberto de Leiva, Oded Langer in Textbook of Diabetes and Pregnancy, 2018
An important question is how early in gestation can placental changes related to diabetes be seen. Following fertilization, placentation is initiated when the trophoblast develops as a cell area that is distinct from the inner cell mass that will form the embryo. The progenitor cytotrophoblast cell is the stem cell of the placenta. These cells proliferate throughout gestation, differentiating along two pathways to form villous cytotrophoblast that ultimately will become either syncytiotrophoblasts (outer cellular layer) or extravillous cytotrophoblasts (inner cellular layer). The syncytiotrophoblast has several functions, including transport of gases, nutrients, and waste products and synthesis of peptide and steroid hormones that regulate placental, fetal, and maternal systems. The extravillous trophoblast (EVT) has a proliferative component and an invasive component. Invasive EVT that invades the decidua is called interstitial EVT, whereas EVT that invades and remodels the spiral arteries is called the endovascular EVT. Endovascular invasion (intramural or intra-arterial) results in displacement of vascular smooth muscle and endothelial cells and transforms the narrow spiral arteries into a low-resistance high-capacity vascular bed.
Expression of Major Histocompatibility Antigens on Fetal and Placental Cells
Gérard Chaouat in The Immunology of the Fetus, 2020
Cytotrophoblast cells specifically isolated from term placentas can be characterized by their cell surface antigens, genetic origin, tissue-specific enzymes, and morphological appearance. They constitute the major placental cell population. These cytotrophoblast cells have undetectable levels of HLA A, B, and C antigens on their surface. The levels of mRNAs corresponding to HLA antigens and B-2 microglobulin, respectively, are extremely low (300-fold lower than in normal lymphocytes). These results are consistent with regulation at the level of transcription or, conceivably, stability of HLA A, B, and C mRNAs.63 It has also been shown that these cytotrophoblast cells are not induced to express HLA antigens upon treatment by IFN-gamma.64 The Jar choriocarcinoma cell line that is HLA-negative behaves the same, whereas, expression of Class I HLA antigens is enhanced in response to IFN-gamma in BeWo cells that are weakly HLA-positive.65
Pregnancy-Related Proteins Detected by Immunochemical or Physicochemical Methods
Gábor N. Than, Hans Bohn, Dénes G. Szabó in Advances in Pregnancy-Related Protein Research, 2020
The localization of PP20 was investigated by Inaba et al.126 In human early placentas, the protein was localized in the cytoplasm of syncytiotrophoblast, cytotrophoblast, as well as chorionic trophoblast. In term placentas, the protein was clearly localized in the cytoplasm of Hofbauer-like cells in the villous stroma as well as in reflected and basal chorionic trophoblast. PP20 appeared not to be localized in the term villi. These findings suggest that the villous syncytiotrophoblast may lose the ability to produce this protein with placental aging. PP20 also could be localized in the cytoplasm of umbilical cord epithelium and certain decidual cells. In contrast to most of the other soluble placental tissue proteins, PP20 could not be localized in polymorphonuclear neutrophils.126 With an electroimmunoassay, PP20 could not be detected in normal sera, pregnancy sera, cord blood sera, and amniotic fluid. This means that the concentration of this protein in human body fluids must be at least < 1 mg/l.129
Cadmium-induced preeclampsia-like phenotype in the rat is related to decreased progesterone synthesis in the placenta
Published in Xenobiotica, 2022
Xiaojie Zhang, Kai Chen, Zhu Meng, Ru Jia, Feifei Lian, Feng Lin
The placentae of humans and rats are both anatomically categorised as discoid and hemochorial types, as the trophoblasts of both are directly bathed in maternal blood (Furukawa et al. 2019; James et al. 2021). So, rats are considered to be important in vivo models for pregnancy-associated pathological research. Both human and rat placentae are histologically divided into a foetal part and a maternal part. In humans, the foetal part is composed of placental villi and basal plate, and the maternal part consists of the decidua. In rats, the foetal part contains the labyrinth zone, basal zone, and yolk sac while the maternal part includes the decidua and metrial gland. The foetal–maternal interface of the human placenta consists of a single syncytiotrophoblast layer and a single cytotrophoblast layer. However, the interface of the rat placenta is comprised of three layers (Furukawa et al. 2011, 2019). Although, to some extent, the placental histological structure and the foetal–maternal interface are different between rats and humans, the labyrinth zone of the rat placenta, which is the research target of our present study, is functionally analogous to the villi of the human placenta (Furukawa et al. 2019; James et al. 2021).
Oxytocin modulates steroidogenesis-associated genes and estradiol levels in the placenta
Published in Systems Biology in Reproductive Medicine, 2023
Sung-Min An, Min Jae Kim, Jea Sic Jeong, So Young Kim, Da Som Kim, Beum-Soo An, Seung Chul Kim
The placenta is a pregnancy-specific and transient tissue that connects the developing fetus to the uterine wall for exchange of nutrients, excretion, antibody transport, gas exchange, and hormone secretion through the maternal-fetal interface (Benirschke et al. 1998; Burton and Fowden 2015). During pregnancy, placental development is an essential process for successful pregnancy and fetal growth (Kwak et al. 2019). For placental growth and development, the proliferation of mononucleated cytotrophoblast (CTB) cells and their morphological differentiation into multinucleated syncytiotrophoblast (STB) cells are required (Kliman et al. 1986). The differentiated STB plays various critical functions throughout pregnancy, including transport of ions, substrates, gases, and other factors between the maternal and fetal circulations (Hubert et al. 2010). In addition, during pregnancy, these cells synthesize and secrete a large amount of steroid hormones, which are essential for fetal growth, through steroidogenesis (Hubert et al. 2010). Among them, estradiol (E2) and progesterone (P4) are the major steroid hormones, and the serum levels of E2 and P4 increase throughout pregnancy (Kim et al. 2016; Young et al. 2016).
The balance between cell survival and death in the placenta: Do neurotrophins have a role?
Published in Systems Biology in Reproductive Medicine, 2022
Prachi Pathare-Ingawale, Preeti Chavan-Gautam
During the early implantation, the outer trophectoderm layer of the blastocyst gives rise to the trophoblast cells of the placenta. In early placental development, the trophoblasts differentiate into the villous and extravillous types of trophoblast, and apoptosis is a normal attribute of cell turnover (Huppertz et al. 2006). The villous syncytiotrophoblast layer, which is in direct contact with the maternal blood, is formed by the fusion of the underlying cytotrophoblast cells. The cytotrophoblast fusion process integrates the cytoplasm and nuclei, which involve the apoptotic cascade events. Some studies show that a part of the enzymatic machinery of the apoptotic cascade is involved in cell differentiation processes. The formation of syncytiotrophoblast has been suggested to involve the externalization of phosphatidylserine, caspase-8 activation, and DNAse activity which resembleing some features of apoptosis (Burton et al. 2003; Black et al. 2004; De Falco et al. 2004; Gauster and Huppertz 2010). Heazell and Crocker reviewed the importance of the pro and anti-apoptotic factors in regulating apoptosis in villous trophoblasts (Heazell and Crocker 2008). Thus, apoptosis is a feature of the villous trophoblast in normal pregnancy and has a potential role in the cytotrophoblast fusion and syncytiotrophoblast function. However, the regulatory mechanism is only partly understood.
Related Knowledge Centers
- Epidermal Growth Factor
- Glucocorticoid
- Implantation
- In Vitro
- Syncytiotrophoblast
- Trophoblast
- Stem Cell
- Blastocyst
- Extravillous Trophoblast
- Chorionic Villi