Mother and Embryo Cross Communication during Conception
Carlos Simón, Carmen Rubio in Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
The process of implantation is divided into three stages: apposition, attachment (adhesion), and penetration. Implantation is initiated when the blastocyst meets the uterine wall. The first step is the release from the zone pellucida, a glycoprotein layer surrounding the plasma membrane, a process called “zona hatching.” Apposition is the loose connection between the blastocyst and the uterine epithelium. Usually, the apposition occurs in a small crypt in the endometrium, aligning the ICM with the uterine wall. Attachment is the furthest and strongest connection, when trophoblasts adhere and penetrate the endometrium, followed by invasion, embedding the embryo in the endometrium. Eventually, the syncytiotrophoblasts, the protrusions of trophoblast cells, come into contact with maternal blood and form chorionic villi, initiating the formation of the placenta [29].
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
Regulation of Reproduction by Dopamine
Nira Ben-Jonathan in Dopamine, 2020
Luteinization involves increased proliferation of capillaries and an irreversible differentiation of granulosa and theca cells to a luteal cell phenotype. A breakdown of the membrane that separates between theca and granulosa cells enables the mingling of the luteinized cells. The biochemical hallmark of luteinization is the capacity for progesterone biosynthesis in response to LH. If the egg is not fertilized, the corpus luteum degenerates after about 10 days and becomes scar tissue called the corpus albicans. If the egg is fertilized and uterine implantation ensues, the developing syncytiotrophoblast secretes human chorionic gonadotropin (hCG), which signals the corpus luteum to survive throughout pregnancy. The corpus luteum of pregnancy continues to release progesterone, which maintains an appropriate endometrial milieu for embryonic development. More discussion on these processes is presented in the next sections.
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).
Silver nanoparticles suppress forskolin-induced syncytialization in BeWo cells
Published in Nanotoxicology, 2022
Yuji Sakahashi, Kazuma Higashisaka, Ryo Isaka, Rina Izutani, Jiwon Seo, Atsushi Furuta, Akemi Yamaki-Ushijima, Hirofumi Tsujino, Yuya Haga, Akitoshi Nakashima, Yasuo Tsutsumi
Construction of the syncytiotrophoblast via the cell fusion process is essential to the placental formation process. The endogenous retrovirus genes ERVW-1 and ERVFRD-1 play an important role in facilitating this fusion process (Orendi et al. 2010). Both ERVW-1 and ERVFRD-1 have cell-fusion activity, but there are differences in their expression patterns in placental cells. The ERVW-1 is expressed in not only syncytiotrophoblast cells but also mononuclear cytotrophoblast cells, whereas ERVFRD-1 is expressed only in mononuclear cytotrophoblast cells (Malassiné et al. 2007; Holder et al. 2012). Because of this difference, it is considered that ERVFRD-1 promotes fusion between mononuclear cells and ERVW-1 is involved in fusion between syncytiotrophoblast cells and mononuclear cytotrophoblast cells (Nakamura and Imakawa 2011). Moreover, it is reported that reduced expression of Syncytin-1 and Syncytin-2 correlates with severity of preeclampsia and impaired cell fusion and differentiation in placentae from patients with intrauterine growth restriction. Furthermore, Syncytin-2 knockdown BeWo cells more suppressed syncytialization compared to Syncytin-1 knockdown BeWo cells (Vargas et al. 2009) indicating that Syncytin-2 could play a critical role in syncytinization. Present study showed that nAg10 suppressed the expression of ERVFRD-1 mRNA. Thus, it is considered that nAg10 could be involved in placental hypoplasia by suppressing the expression of ERVFRD-1.
A stroll through the present and future of testicular germ cell tumour biomarkers
Published in Expert Review of Molecular Diagnostics, 2023
Nuno Tiago Tavares, Rui Henrique, Aditya Bagrodia, Carmen Jerónimo, João Lobo
On the other hand, HCG is a 38 kDa glycoprotein hormone that has five different isoforms and has been routinely used for a long time in pregnancy tests. TGCTs may cause serum elevations of the whole HCG or the β-unit of this hormone, β-HCG [31]. This hormone is produced by the syncytiotrophoblast cells and plays several roles in pregnancy, promoting development of the placenta and differentiation of fetal organs [32]. The half-life of β-HCG in serum ranges from 18 to 36 h, much lower than that of AFP. Like the former, its production is dependent on TGCT histologic type, being markedly elevated in the presence of trophoblastic elements, including scattered syncytiotrophoblast cells or CHC foci. For SE, this marker is elevated in about 18–31% of all patients, specifically 10–20% of clinical stage I patients and 30–50% of advanced disease [22,23,33]. For NST, it is elevated in about 53% of patients and in more than 95% CHC cases [22,23]. β-HCG may also be elevated in other types of cancers and due to heterophilic antibodies, a fact that lowers its specificity for GCTs, which is about 35–37% [25,26,34,35].