Trophoblast invasion definition
Trophoblast invasion definition. Trophoblast invasion is transient, with stringent spatial and temporal control. Unsuccessful invasion is now recognized to lead to pregnancy diseases, such as preeclampsia (PE). Dec 27, 2022 · Trophoblast vasculogenic mimicry is characterized by endovascular invasion of trophoblast cells into maternal arteries. The current model posits that the primary cause of this suboptimal endovascular invasion is a failure of the decidua to tolerate and/or facilitate trophoblast invasion. 1210/en. (Kaufmann et al. However, unlike cancer cells, both initiation and the extent of trophoblast invasion are tightly regulated by feto-maternal cross-talk, which when perturbed, results in a wide range of abnormalities. Aug 24, 2023 · In conclusion, KRT18 is highly expressed on trophoblast cells of blastocysts. Placentas differ in cellular composition, histological arrangement and gross morphology, as well May 15, 2020 · If histologic sections do not show infiltration of trophoblast into perivesical fat or infiltrative invasion in the myometrium immediately adjacent to the defect, correlation with surgical and Define trophoblast. Trophoblast dysfunction results in many pregnancy complications, including recurrent pregnancy loss (RPL). Invasion Illustration of an implanting embryo. , JAR and HTR-8/Svneo). Jan 14, 2016 · The last step of implantation is the invasion process, which involves penetration of the embryo through the luminal epithelium into the endometrial stroma; this activity is mainly controlled by the trophoblast . During subsequent development of the placenta, trophoblast invades the decidualized endometrium and migrates into the spiral arteries. The outermost layer of Oct 24, 2016 · Quantification of trophoblast invasion. Jul 30, 2020 · Trophoblast lineage, which describes the developmental sequence of the placenta, consists of trophectoderm (TE), cytotrophoblast (CT), syncytiotrophoblast (ST) and extravillous trophoblast (EVT; also called intermediate trophoblast) (Lee et al. Our study outlines a new m 1 A epigenetic way to regulate the trophoblast activity, which suggests a novel Ligands. 2 ). During this process, invasive trophoblast replace vascular endothelial cells as the uterine arteries are remodeled to form more permissive vessels that facilitate adequate blood flow to the growing fetus. They are derived from the trophoectoderm of the developing blastocyst. Trophoblast stem cells (TSCs) and trophoblast progenitor cells (TPCs) differentiate into more specialized trophoblast populations at an early stage of development. Trophoblast cells undergo various forms of RCD, which can influence their proliferation, invasion, and uterine Sep 9, 2004 · Trophoblast invasion and maturation of the maternal-fetal interface Trophoblast stem cell self-renewal. Decreased or absent trophoblast invasion may be a consequence of primary defects in the invasive trophoblasts or in the environment that the trophoblasts are attempting to invade. The trophoblast lineage is the first to differentiate during human development, at the transition between morula and blastocyst. Reduced uteroplacental perfusion associated with maternal vascular disease is responsible for 25–30% of FGR cases; it is the most common cause in non-anomalous fetuses. On the other hand, autophagy has been describes as an important regulator of cancer immunity in the tumor microenvironment; however, the exact mechanisms involved remain Feb 12, 2024 · Extravillous trophoblasts are pivotal in placental invasion and artery remodeling. This event constitutes the basis of the conversion of the uterine spiral arteries, a process which allows an adequate vascular connection between the intervillous space and the maternal blood flow. A) Mouse placenta: the labyrinth is the functional structure where gas/nutrient exchange occurs. Cytotrophoblasts initially express epithelial cell-type adhesion molecules such as integrins α 6 /β 4 and α 6 /β 1, and E-cadherin. During early human pregnancy extravillous cytotrophoblasts invade the uterus and spiral arteries transforming them into large vessels of low resistance. Invasion is the further establishment of the blastocyst into the endometrium. n. Inadequate trophoblast invasion not only leads to implantation failure 1 and spontaneous pregnancy loss but also results in the insufficient remodeling of spiral arteries that sits at the epicenter of the great obstetric syndromes, including idiopathic fetal Jun 8, 2020 · The pathologic hallmark is shallow trophoblast invasion and a failure of spiral artery remodeling. Feb 16, 2023 · Pre-eclampsia is a life-threatening disease of pregnancy unique to humans and a leading cause of maternal and neonatal morbidity and mortality. The closer the trophoblasts are to the endometrium the less hCG is made, allowing the Mar 1, 2016 · 1. We first report that in human first Abstract. Mouse trophoblast stem (TS) cells have been derived and used as the best in vitro model for molecular and functional analysis of mouse trophoblast lineages, but attempts to derive human TS cells have so far been unsuccessful. Trophoblast invasion and remodeling of the spiral arteries is in part regulated by integrins and other adhesion molecules. Within the placenta the syncytiotrophoblasts generate high levels of hCG which shifts cytotrophoblast differentiation towards a non-invasive hormone secreting villous-type trophoblast. Apparently paradoxical results came from the rat study, i. Both processes properly occur as a consequence of an intimate dialogue between fetal and maternal tissues, fulfilled by membrane ligands and receptors, as well as by hormone and local factor release. Toward this end, we utilized a model system of extravillous trophoblast (EVT) organ culture and various placenta cell lines (e. PPAR alpha. The process is also necessary for transforming the uterine spiral arteries [ 22 ]. Jul 7, 2022 · These results identified a novel SC-specific CTB population important for establishment of a protective barrier and the suppression of trophoblast invasion. Jun 18, 2020 · Outcomes: Deep trophoblast invasion into the maternal decidua is a particular feature of human pregnancy. 27. However, to achieve mature Thus, Lefty may promote the proliferation and invasion of trophoblast cells, thereby reducing the amount of apoptosis of these cells. The invasion of a specific type of trophoblast (extravillous trophoblast) into the maternal uterus is a vital stage in the establishment of pregnancy. Trophoblast cells play an essential role in the interactions between the fetus and mother. b Development of the first placental structures and the embryonic disc. The syncytiotrophoblast (from the Greek 'syn'- "together"; 'cytio'- "of cells"; 'tropho'- "nutrition"; 'blast'- "bud") is the epithelial covering of the highly vascular embryonic placental villi, which invades the wall of the uterus to establish nutrient circulation between the embryo and the mother. d Development of tertiary villi and the embryonic germ layers. Apr 19, 2023 · Successful placentation, which involves invasion of extraembryonic trophoblast cells into the maternal decidua, is essential for both maternal and fetal health. Trophoblast invasion starts from the trophoblastic shell that is the base of the lacunar system at day 8 after conception (see Figure 10-1, C and D ). The protrusions of trophoblast cells that adhere into the endometrium continue to proliferate and penetrate into the endometrium using gelatinases A , and B . In the current study we examined the expression and role of the PPARgamma/RXRalpha heterodimers in human invasive trophoblasts. Let’s delve into the key aspects of this stage: During invasion, trophoblast cells, which have adhered to the endometrium, continue to proliferate and penetrate deeper into the endometrial tissue. The placenta is a transient fetal organ that plays a critical role in the health and wellbeing of both the fetus and its mother. This invasion needs to be finely regulated to allocate resources between mother and baby. Functionally, the placenta sustains the growth of the fetus as it facilitates delivery of oxygen and nutrients and removal of waste products. The mechanisms regulating invasion remain poorly understood, although interactions with the uterine environment are clearly of central Mar 15, 2022 · Abstract. In the beginning, it is a purely syncytiotrophoblastic layer. As the main link between the mother and the fetus it has more diverse functions than any other organ, serving as a digestive, excretory, respiratory, endocrine, and immune system. The range of cellular functions originating from a relatively small number of trophoblast cell differentiation events is formidable. , 2014). Diagrammatic. Corticotropin-releasing hormone binding protein (CRHBP), belonging to the CRF family, is fundamental in the stress response and plays important role in parturition Oct 3, 2022 · Mice have minimal trophoblast invasion into the decidua, and the transformation of spiral arteries in mice is mediated mainly by uNK cells secreting interferon-γ rather than by extravillous Abstract. Invasion into uterine glands by endoglandular trophoblasts has been identified to take place as early as during the first days of implantation . It leads to envelopment of the blastocyst by the endometrium, i. From day 13 after conception onward, cytotrophoblasts enter the trophoblastic trabeculae and villi. trophoblast. Here the authors report stage-specific transcriptional regulators and their sequential roles in guiding proper Jun 18, 2023 · Invasion is a critical stage in the process of implantation where the blastocyst further establishes itself into the endometrium. Mar 21, 2024 · Das Trophoblast ist eine Zellschicht, welche die äußere Begrenzung der Blastozyste bildet und für die Ernährung des Embryos verantwortlich ist. These specialized trophoblast cells single-handedly redirect maternal physiology to support the survival and growth of the fetus. A reliable source of EVT is needed to study in vitro how the uterine environment regulates this process. Mar 11, 2017 · Abnormal placentation has been defined as a condition in which trophoblast invasion of the myometrial portion of the spiral arteries does not occur . Knockdown of KRT18 impaired trophoblast migration and invasion. Within each section, only regions with trophoblast invasion were assessed for this study. Trophoblast cells are an intriguing and unique cell lineage. As with many gestational disorders, further research needs to be conducted to determine why PAS Feb 24, 2024 · The placenta serves as an essential organ for fetal growth throughout pregnancy. This section will cover the etiopathogenesis, imaging findings, definition, risk factors, and pathology of the abnormally located and morbidly adherent placenta. Once the embryo is anchored within the uterine wall, the next major hurdle is rapid formation of the extraembryonic lineages, a necessary prelude to assembly of the maternal-fetal interface. These cell types are morphologically and functionally distinct. The expression and role of PPARα in trophoblast cells are not very well known. Methylation-mediated silencing of inhibitors of Wnt signaling provided evidence for epigenetic activation of the pathway in placental tissues and choriocarcinoma cells. Disturbed remodeling is associated with maintenance of high uteroplacental vascular resistance and Mar 15, 2022 · Our implantation-on-a-chip is capable of reconstructing the three-dimensional structural organization of the maternal-fetal interface to model the invasion of specialized fetal extravillous trophoblasts into the maternal uterus. c Formation of primary villi and yolk sac. Abstract. [ trof´o-blast] the peripheral cells of the blastocyst, which attach the zygote (fertilized ovum) to the uterine wall and become the placenta and the membranes that nourish and protect the developing organism. . Successful establishment of pregnancy requires adhesion of an embryo to the endometrium and subsequent invasion into the maternal tissue. Trophoblast plugs (A) are composed of endovascular trophoblast cells. Jun 12, 2018 · Stem cells, by definition, have the capacity for both self-renewal and differentiation into different lineages. The Peroxisome Proliferator-Activated Receptor-alpha (PPARα) is a member of the ligand-dependent nuclear receptor superfamily known for their crucial role in lipid metabolism. In a plugged artery May 3, 2019 · Development of the human placenta during the first 3 weeks of gestation. The result is a poorly-oxygenated environment and reduced fetal growth. The mechanisms which direct morphogenesis of the chorionic villi, and the interactions between trophectoderm-derived trophoblasts and the fetal mesenchyme to direct The concept of venous invasion does not question but rather broadens the concept of arterial trophoblast invasion, which is associated with extensive remodeling, transformation and plugging of the arteries. Apr 14, 2021 · Indeed, suppression of autophagy in an in vitro model of trophoblast cells enhances the cytotoxicity activity of dNK, impairing trophoblast invasion, finally causing abortion . Multiple forms of regulated cell death exist at the maternal-fetal interface. Jan 17, 2023 · The primary factor in IUGR is placental dysfunction caused by a failure of the extravillous trophoblasts to penetrate and modify the uterine spiral arteries. The outer layer of the placenta, the trophoblast, plays a key role in fetal development by Nov 1, 2022 · Human placental development and function. This new route of invasion into uterine veins asks for a new definition of the terminology of extravillous trophoblast. However, unlike tumor invasion, trophoblast invasion of the uterus should be under strict control confining the placenta and within the time constraint of a pregnancy. May 22, 2020 · BACKGROUND. a Human blastocyst implanting into the pregnant uterus. This condition occurs when the placenta adheres to the bottom of the uterus and partially or fully eclipses the cervix, preventing the delivery of the fetus [49]. Failure of the trophoblast to invade sufficiently is important in the development of some cases of pre-eclampsia. In the case of trophoblast stem cells, the well-known differentiation pathways are trophoblast: [noun] the outer layer of the mammalian blastocyst that supplies nutrition to the embryo and facilitates implantation. These specialized populations of trophoblast cells either displace endothelial cells or are located underneath the vascular endothelium ( Rai & Cross, 2014 ). 3A: Trophoblast Development is shared under a license and was authored, remixed, and/or curated by LibreTexts. Sep 9, 2020 · The first in vitro model system of human trophoblast that could be cultured long term and differentiated to syncytiotrophoblast (SCT) and extravillous trophoblast (EVT) was a two-dimensional (2D Apr 3, 2023 · Notably, the deep interstitial trophoblast invasion observed in humans is unique to great apes 5. In contrast, 2 groups have reported reduced interstitial invasion in preeclampsia. According to the depth of trophoblast invasion into the myometrium, three known variants of PAS can be differentiated by pathologists: 1 placenta accreta (also called placenta creta, vera, or adherenta), where the chorionic villi attach directly to the surface of the myometrium in the absence of the decidual layer; 2 placenta increta, where the chorionic villi penetrate deeply into Abstract. The control of invasion, both initiation Feb 2, 2016 · In vivo, trophoblast cells can be identified by their anatomical location and the expression of particular markers. Altered uteroplacental blood flow is a core predictor of abnormal pregnancy. Fenofibrate. Jun 14, 2022 · The migration and invasion of trophoblast cells at the maternal–fetal interface is a key process of embryo implantation. 2009; 150:1000–1013. Inadequate invasion of trophoblast cells may cause abortion, fetal growth restriction, fetal death, preeclampsia, etc. Jan 1, 2022 · Increased trophoblast invasion is also a common occurrence with placenta previa [49]. In humans, inadequate trophoblast invasion into the decidua is associated with the ‘great obstetrical syndromes’ which include pre-eclampsia, foetal growth restriction (FGR) and stillbirth. Using primary human cells isolated from clinical specimens, we demonstrate in vivo-like directional migration of Feb 9, 2016 · In vivo, trophoblast cells can be identified by their anatomical location and the expression of particular markers. Obstructions to its development can lead to pregnancy complications, such as preeclampsia, fetal growth restriction, and preterm birth, posing severe health risks to both Dec 31, 2019 · Of course, such new routes of trophoblast invasion may well be altered, especially in pregnancy pathologies such as intra-uterine growth restriction, preeclampsia, early and recurrent pregnancy loss, stillbirth, and spontaneous abortion. Oct 10, 2023 · The placenta-on-a-chip has been used to study trophoblast invasion, toxicological screening, microvilli formation, placental pathology, and placental exosome capture. In vitro, there is a lack of consensus about the best criteria to use to define trophoblast. Normally, the uteroplacental arteries are invaded by endovascular trophoblast and remodeled into dilated, inelastic tubes without maternal vasomotor control. e. Endocrinology. Placenta accreta spectrum (PAS) disorders are associated Jun 5, 2022 · The more trophoblast cell columns develop during placentation, the more EVTs can reach the spiral arteries from various sites. Jan 8, 2016 · Trophoblast migration and invasion is often compared to tumor metastasis, which uses many of the same molecular mechanisms. the peripheral part of the human conceptus, exerts a crucial role in implantation and placentation. Trophoblast cell lines have become an invaluable tool to study various aspects of trophoblast biology. Women who survive pre-eclampsia have reduced life Significantly, one of the most frequent findings in preeclampsia is decreased or absent trophoblast invasion of the maternal spiral arteries. 2. These cell lines are more resilient when compared to cultures of primary trophoblast cells, including extended lifespans in culture, and are thus advantageous for studies encompassing more detailed investigations of trophoblast function and molecular biology. , 2016). Trophoblast invasion is one of the most criti …. Feb 26, 2024 · 1. Jan 8, 2016 · ABSTRACT. 2008-0456 Crossref Medline Google Scholar; 74. In addition, trophoblast spheroid adhesion and mouse embryo adhesion and implantation were impaired due to failed interactions with E-cadherin. In addition, these data represent a resource of CTB types, proportions, and gene expression at mid-gestation against which age-related and pathogenic alterations can be measured. Summary. Sep 26, 2022 · In a normal pregnancy, the placenta anchors to decidualized endometrium. [1] The abnormal invasion of placental trophoblasts into the uterine myometrium is called placenta accreta. A distinctive feature of trophoblast is its profile of human leukocyte antigen (HLA) class I expression. reader decreased invasion and migration of trophoblast by inhibiting IGF1R expression. The invasion of extravillous trophoblast (EVT) into the decidualized endometrium is crucial in the determination of pregnancy outcome. Shallower invasion leads to inadequate transformation of the spiral arteries, thereby limiting the blood supply to the intervillous space, and is causally associated with fetal growth restriction and preeclampsia Cutting-edge and thorough, Trophoblasts: Methods and Protocols is a valuable resource that will help researchers better understand the function of the placenta and its complex contribution to maternal health and fetal development, and also provide greater insights to the area of study known as the developmental origins of health and diseases Mar 1, 2020 · The rat, in which trophoblast cells exhibit extensive interstitial and endovascular invasion, could be a suitable model animal for the study of human spiral artery remodeling. 48,49 The variation in trophoblast invasion in different areas of the placenta occurs because trophoblast invasion goes on for a longer period of time at the earliest Nov 28, 2018 · a, Schematic of a placental villus at the maternal–fetal interface in the first trimester of pregnancy showing the different trophoblast subsets: SCT, VCT, CCC and EVT. When trophoblast cells overexpressing Nodal were treated with Lefty, Nodal expression increased, and MMP-2 and MMP Figure 4. Sources of the intrinsic Mar 16, 2018 · Background The initiation of primate embryo invasion into the endometrium and the formation of the placenta from trophoblasts, fetal mesenchyme, and vascular components are essential for the establishment of a successful pregnancy. The inner cellular layer is the cytotrophoblast and the outer layer is the syntrophoblast. implantation is interstitial. Apr 26, 2020 · Identification of novel trophoblast invasion-related genes: heme oxygenase-1 controls motility via peroxisome proliferator-activated receptor gamma. Dec 31, 2017 · During early pregnancy, fetal trophoblast cells invade the uterus and penetrate the basement membrane, a property that is characteristic of malignant cells. Mar 5, 2015 · Trophoblast invasion of the uterus is a necessary step at implantation of the human blastocyst. Feb 22, 2002 · Trophoblasts are the first cells to differentiate in the embryo. Implantation abnormalities are a group of disorders encompassing several entities with different degree of severity. Depending on the stage of invasion and on the localization of sectioning the lumen of the spiral artery can be either completely filled with trophoblasts (1, 2) or (B) partly infiltrated (3, 4). Pregnancy success is determined by a complex progress that includes trophoblast invasion and placentation. Thereafter, invasion into uterine veins takes place by endovenous trophoblasts to allow backflow of secretion products of the uterine glands into the maternal system [22, 23, 24, 25]. 1 day ago · Trophoblast plugs within Spiral Arteries Week 9, GA week 11. Defective trophoblast invasion in Feb 8, 2007 · The trophoblast, i. Trophoblast invasion is a key process during human placentation. Growth factor expression/secretion is stimulated by paracrine interactions of diverse maternal and placental cell types. Nov 21, 2013 · The invasion of maternal tissue by trophoblast-derived cells is a specific and constant feature of human placentation ( Goldman-Wohl and Yagel, 2002; Carter and Mess, 2007 ). Proper trophoblast differentiation is crucial to the vitality of this gestational organ. Based on the degree of myometrial invasion, it is considered a spectrum of disorders, encompassing placenta accreta, placenta increta, and placenta percreta. , exposure to hypoxia or depletion of dNK cells resulted in acceleration of the endovascular trophoblast invasion. The trophoblast is a very interesting structure from an embryological and also histopathological point of view. Apr 15, 2022 · Trophoblast invasion of the uterus is the first step to implantation of the human blastocyst. Jul 28, 2021 · In a healthy pregnancy, trophoblast invasion extends through the relatively shallow endometrium to the inner third of the myometrium. The invasion of the uterine wall by extravillous trophoblast is acknowledged as a crucial component of the establishment of pregnancy however, the only part of this process that has been clearly identified is the differentiation of cytotrophoblast (CTB) into the invasive extravillous trophoblast (EVT). Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are metal-dependent endopeptidases capable of degrading extracellular matrix, and appear to play a critical role in trophoblast invasion. Regulation of trophoblast invasion by an hCG gradient. Jul 1, 2003 · Maternal uteroplacental blood flow increases during pregnancy. Trophoblast migration and invasion through the decidua and maternal uterine spiral arteries are crucial events in placentation. For quantification of trophoblast invasion, serial sections from 16 placentas were immuno-stained with an antibody against desmin and immuno-double-stained with antibodies against von Willebrand factor (vWF)/HLA-G. Abnormalities in this critical process of implantation and placentation lead to many pregnancy complications. Aug 12, 2023 · Placental development is a tightly controlled event, in which cell expansion from the trophectoderm occurs in a spatiotemporal manner. doi: 10. Until recently, trophoblast invasion during human placentation was characterized by and restricted to invasion into uterine connective tissues and the uterine spiral arteries. Various players, such as proteins, cytokines, transcription factors and microRNAs, have influence on the process of endovascular trophoblast invasion and respective mechanisms are continuously presented and published. We review the definitions of the placental bed and basal plate of the placenta, their relevance Sep 25, 2013 · Indeed, activation of the pathway was shown to promote trophoblast invasion in different in vitro trophoblast model systems as well as trophoblast cell fusion. Lefty siRNA knockdown or overexpression of Nodal showed opposite effects to treatment with Lefty. Failure of trophoblast invasion and spiral artery transformation occurs in preeclampsia and fetal growth restriction (FGR); these processes are not well understood. Here we present a microenigneered system to model a complex sequence of orchestrated The ligand-dependent nuclear receptors PPARgamma and RXRalpha/beta were recently determined to be essential for murine placental development and trophoblast differentiation. 19,56,150-153. The mechanisms which direct morphogenesis of the chorionic villi, and the interactions between trophectoderm-derived trophoblasts and the fetal mesenchyme to direct Nov 21, 2013 · The invasion of maternal tissue by trophoblast-derived cells is a specific and constant feature of human placentation ( Goldman-Wohl and Yagel, 2002; Carter and Mess, 2007 ). , 2003; Soares et al. g. The development of the human embryo progresses rapidly immediately after implantation, and the trophoblast enables the embryo to adhere to the uterine epithelium, facilitating embedding into the endometrial wall and forming the future fetal part of placenta. Activation of PAR1 induces EVT invasion while hPar1-SiRNA and PAR1 antagonist SCH79797--effectively inhibited it. Nov 10, 2020 · Definition. The latter was explained to connect the arteries to the intervillous space of the placenta and to guarantee the blood supply of the mother to the placenta. Normal implantation is critical for a successful pregnancy. Jul 24, 2018 · Abstract. George EM, Cockrell K, Aranay M, Csongradi E, Stec DE, Granger JP. Maternal blood is separated from fetal blood by three layers of trophoblast (SynT-I, SynT-II and sinusoidal giant cells). During blastocyst implantation, generation of distinct trophoblast cell Indeed, several factors promoting trophoblast invasion, such as IGF-I, IL-1 or EGF, were shown to increase hCG expression and secretion ( Fig. Dec 1, 2020 · The invasion of the uterine wall by extravillous trophoblast is acknowledged as a crucial component of the establishment of pregnancy however, the only part of this process that has been clearly identified is the differentiation of cytotrophoblast (CTB) into the invasive extravillous trophoblast (EVT). Maybe one or more of these pregnancy pathologies show alterations in different pathways of trophoblast Oct 12, 2016 · The mature human placenta demonstrates the deepest trophoblast invasion of spiral arteries at its center, with the depth gradually decreasing toward the periphery of the placenta. This article reviews the anatomy and physiology of the uterine circulation, with emphasis on the remodeling of spiral arteries during normal pregnancy, and the timing and anatomical pathways of trophoblast invasion of the spiral arteries. Introduction. The placenta is the first organ to be created during mammalian development. Final Thoughts. In parallel, the Wnt inhibitor Dickkopf-1 (Dkk1) similarly inhibited it. Mar 16, 2018 · Background The initiation of primate embryo invasion into the endometrium and the formation of the placenta from trophoblasts, fetal mesenchyme, and vascular components are essential for the establishment of a successful pregnancy. trophoblast synonyms, trophoblast pronunciation, trophoblast translation, English dictionary definition of trophoblast. 30,31 The differences may relate to the fact that Kadyrov et al 30 studied a small number of archived cesarean hysterectomy specimens that are known to lose their ability to stain for antibodies, and placental bed was defined by the presence of trophoblast alone Trophoblast invasion is critical for placentation and pregnancy success. First, we critically discuss the issues with Although both mouse and human placentas are hemochorial, some structural differences can be observed. These cells are essential for the maintenance and inception of a successful pregnancy (Benirschke and Kaufman, 1995), for it is the trophoblast which adheres to the uterus and initiates the implantation process. Histone modification is a crucial regulatory mechanism involved in numerous biological processes and development. rx jb dp gj yc fj tm br mi sf