Immature Intermediate Villi Research Articles

Placental Mesenchymal Dysplasia Co-existing with High Grade Villitis of Unknown Aetiology (VUE): A Very Rare Case Report and Literature Review

The present case study reports about Placental mesenchymal dysplasia co-existing with high grade villitis of unknown aetiology (VUE). Placental Mesenchymal Dysplasia (PMD) is a rare placental lesion characterized by unusual abnormality of the stem villi of the placenta that could be mistaken for hydatidiform mole due to the presence of both cysts and normal-appearing parenchyma. A 30-year-old G2 P1 (full-term normal delivery) seen in fetal medicine clinic at 20 weeks within view of high risk on combined screening (low PAPP-A and high HCG). An ultrasound scan showed an appropriately grown baby with an abnormal placenta consisting of multiple lacunae more than 50% of the placental mass with increased thickness. A second opinion at tertiary care hospital confirmed the presence of prominent lakes on the placenta. Growth scans also showed IUGR with increasingly abnormal Doppler scans as the pregnancy progressed. At 35 weeks, EFW was < 3rd centile with static growth and patient had Induction of labour at 35 +4 weeks with vaginal delivery of a live male neonate weighing 2325g admitted to the neonatal intensive care unit (NICU) admission due to prematurity. The baby was discharged from NICU at day 5, achieving developmental milestones at the age of 23 weeks post-delivery. On microscopic histological examination, the chorionic plate showed no significant abnormality. The villous architecture was highly abnormal, and some villi were markedly enlarged with myxoid stroma and central degeneration. There were very occasional foci of apparent trophoblastic proliferation with villous architecture abnormalities seen in the form of clusters of large, immature intermediate villi. These features were in keeping with mesenchymal dysplasia. A highly unusual finding in this context was a florid infiltrate of CD3 positive T cells consistent with high-grade villitis of unknown aetiology concluding very rare co-existence of both conditions.

СКРИНИНГОВОЕ ПАТОЛОГО-АНАТОМИЧЕСКОЕ ИССЛЕДОВАНИЕ ПОСЛЕДА КАК РЕЗЕРВ ДЛЯ СНИЖЕНИЯ ПЕРИНАТАЛЬНОЙ ЛЕТАЛЬНОСТИ

Introduction. The continuity of the morphofunctional system "mother-placenta-fetus" allows for the histological examination of the placenta to reveal risk groups for the newborn, pregnant women, puerperas, and to take out preventive measures. Aim of the research. To study the structure and localization of pathological changes in the placenta and the significance of mass pathomorphological studies as a reserve for reducing infant and perinatal mortality. Materials and methods. The afterbirths were examined according to the algorithm proposed by A.P. Milovanov (1999). Histological examination assessed the maturity of the placenta, the severity of compensatory-adaptive reactions and involutive-dystrophic changes, noted the presence and severity of inflammatory changes both in the placenta (placentitis, intervillusitis, villusitis) and extraplacental membranes (choriodeciduiitis, chorioamnionitis). Results. In a large-scale pathoanatomical examination of placentas, the proportion of normal mature placentas without pathological findings was up to 20%. The main pathological process in the placenta is an acute and chronic inflammation, often combined with chronic placental insufficiency (up to 77%). Among the forms of chronic placental insufficiency, the variant of pathological immaturity predominates – immature intermediate villi. For severe inflammation, the most common localization was noted in the fetal membranes, which reflects the ascending route of intrauterine infection. For chronic inflammation, the most common localization was basal deciduitis and parietal choriodeciduitis, which is associated with a high incidence of latent infectious foci in women. Conclusion. A large-scale pathoanatomical examination of placentas , with the identification of risk groups for newborns, along with other factors, can serve as a reserve for reducing perinatal and early neonatal mortality.

Impact of gestational hypothyroidism on uterine implantation and reproductive performance in the rat

Impact of gestational hypothyroidism on uterine implantation and reproductive performance in the rat

Human type 2 17beta-hydroxysteroid dehydrogenase mRNA and protein distribution in placental villi at mid and term pregnancy

BackgroundDuring human pregnancy, the placental villi produces high amounts of estradiol. This steroid is secreted by the syncytium, which is directly in contact with maternal blood. Estradiol has to cross placental foetal vessels to reach foetal circulation. The enzyme 17beta-hydroxysteroid dehydrogenase type 2 (17beta-HSD2) was detected in placental endothelial cells of foetal vessels inside the villi. This enzyme catalyzes the conversion of estradiol to estrone, and of testosterone to androstenedione. It was proposed that estradiol level into foetal circulation could be regulated by 17beta-HSD2.MethodsWe obtained placentas from 10 to 26 6/7 weeks of pregnancy from women undergoing voluntary termination of pregnancy, term placentas were collected after normal spontaneous vaginal deliveries. We quantified 17beta-HSD2 mRNA levels in mid-gestation and term human placenta by RT-QPCR. We produced a new anti-17beta-HSD2 antibody to study its spatio-temporal expression by immunohistochemistry. We also compared steroid levels (testosterone, estrone and estradiol) and 17beta-HSD2 mRNA and protein levels between term placenta and endometrium.ResultsHigh 17beta-HSD2 mRNA and protein levels were found in both mid-gestation and term placentas. However, we showed that 17beta-HSD2 mRNA levels increase by 2.27 fold between mid-gestation and term. This period coincides with a transitional phase in the development of the villous vasculature. In mid-gestation placenta, high levels of 17beta-HSD2 were found in mesenchymal villi and immature intermediate villi, more precisely in endothelial cells of the stromal channel. At term, high levels of 17beta-HSD2 were found in the numerous sinusoidal capillaries of terminal villi. 17beta-HSD2 mRNA and protein levels in term placentas were respectively 25.4 fold and 30 to 60 fold higher than in the endometrium. Steroid levels were also significantly higher in term placenta than in the endometrium.ConclusionThe spatial and temporal expression of 17beta-HSD2 in the placenta during pregnancy and the comparison of 17beta-HSD2 expression and steroid levels between placental villi and endometrium are compatible with a role in the modulation of active and inactive forms of estrogens. Our observations strongly support the hypothesis that 17beta-HSD2 acts as a barrier decreasing estradiol secretion rates in the foetal circulation.

Spatial and Temporal Distribution of Tie-1 and Tie-2 During Very Early Development of the Human Placenta

Vasculogenesis in the human placenta comprises differentiation and growth of newly forming blood vessels derived from hemangiogenic stem cells within the mesenchymal core of villi. In a second stage, angiogenesis leads to the expansion and remodeling of the already existing vessels. At present, relatively little is known about the regulatory mechanisms of vasculogenesis and angiogenesis during very early placentation. Using placental villous tissues from days 22 to 48 of pregnancy, we analyzed the spatial and temporal expression of Tie-1 and Tie-2 in parallel to vascular maturation in the human placenta. In immunohistochemistry both receptors, Tie-1 and Tie-2 show a cell and villous type specific expression during this early phase of placental development. Especially, cytotrophoblast and hemangiogenic cell cords in mesenchymal villi and Hofbauer cells in immature intermediate villi have the strongest immunoreactivities. Western blot analysis showed that no significant changes were detected for Tie-1 and Tie-2 as pregnancy advanced. Moreover, phospho-Tie-2 levels did not change significantly in parallel to pregnancy ages. We conclude that both receptors are involved in angiogenesis as well as vascular modulation of early vessels. Due to their spatial distribution we speculate on an additional role in regulation of villous and extravillous trophoblastic behavior.

Human placental vascular development: vasculogenic and angiogenic (branching and nonbranching) transformation is regulated by vascular endothelial growth factor-A, angiopoietin-1, and angiopoietin-2.

During placental development, vessel formation occurs initially by vasculogenesis and subsequently by branching and nonbranching angiogenesis. We investigated vascular endothelial growth factor (VEGF)-A, angiopoietin (Ang)-1 and -2 transcript profiles, and the protein products that they encode in placentas from normotensive pregnancies throughout pregnancy. In addition, we compared these genes in placentas from normotensive women and those with preeclampsia during the third trimester. Quantitative real-time PCR analysis demonstrated that VEGF-A and Ang1 mRNA increased in a linear pattern by 2.5 (not significant) and 2.8%/wk (P = 0.034), respectively, whereas Ang2 decreased logarithmically by 3.5%/wk (P = 0.0003). Ang2 mRNA was 400- and 100-fold higher than Ang1 and VEGF-A, respectively, in the first trimester and declined to 20-fold and 7-fold in the third. Ang2 protein (ELISA) decreased by 4.7%/wk (P = 0.0001), whereas Ang1 and VEGF-A were undetectable. In preeclampsia compared with normotensive pregnancy, only VEGF-A mRNA increased significantly, by 3-fold (P = 0.006). This increase may be related to low oxygen tension, as VEGF-A is up-regulated by hypoxia. In situ hybridization and immunohistochemical studies revealed that VEGF-A was localized in cyto- and syncytiotrophoblast and perivascular cells, whereas Ang1 and Ang2 were only in syncytiotrophoblast and perivascular cells in the immature intermediate villi during the first and second trimesters, and mature intermediate and terminal villi during the third trimester. These data suggest that these molecules may play important roles in placental biology and chorionic villus vascular development and remodeling in an autocrine/paracrine manner. The tight correlation between Ang2 mRNA and protein indicates that regulation of placental vascular development occurs at the transcriptional, and not translational, level.

Development of the placental villous tree and its consequences for fetal growth

Co-ordinated development of the fetal villous tree of the placenta is necessary for continued fetal growth and well-being. Before fetal viability, blood vessel development within the developing immature intermediate villi (IIV) is characterized by branching angiogenesis, such that the placenta expands to produce 10–16 generations of stem villi. Once fetal viability is attained, a developmental switch occurs to form large numbers of gas-exchanging terminal villi (TV) by non-branching angiogenesis in mature intermediate villi (MIV). Several growth factors, including vascular endothelial growth factor (VEGF), placenta growth factor (PlGF), angiopoietins, and angiostatins are produced within the villi and act locally, via their receptors, to control angiogenesis. Their relative contributions to placental vascular development are not fully understood at the present time. Severe early-onset intrauterine growth restriction (IUGR) is characterized by absent/reversed end-diastolic flow velocity (ARED) in the umbilical arteries, leading to fetal hypoxia, acidosis and a substantial rise in perinatal mortality and morbidity. The placentas from such cases show a deficit in peripheral villous development, which may be perpetuated by the effects of oxygen (delivered by maternal blood into the intervillous space) upon VEGF-directed angiogenesis, the so-called ‘placental hyperoxia’ theory of villous maldevelopment. Trophoblast apoptosis is a significant feature of early-onset IUGR and may explain poor flow-independent transfer of nutrients to the fetus. Finally, since transgenic mouse studies highlight the importance of trophoblast-derived transcription factors for placental villous (labyrinth) development, it is possible that the villous trophoblast controls the orderly development of the underlying mesoderm and blood vessels into the fetal villi.

Villous sprouting: fundamental mechanisms of human placental development.

There is increasing evidence that maldevelopment of the placental villous tree can play an important role in the pathogenesis of various pregnancy diseases. In this review we present the most recent advances of cellular and molecular mechanisms involved in the early formation of chorionic villi. In particular we focus our attention on the structural events during early villous sprouting leading to the formation of the mesenchymal villi which are the forerunners of all other villous types, i.e. immature intermediate villi, stem villi, mature intermediate villi and terminal villi. Early villous sprouting starts as 'hot spots' which are circumscribed areas consisting of highly proliferating cytotrophoblastic and stromal cells. The post-proliferative cytotrophoblastic cells fuse with the overlying syncytium leading to the formation of the trophoblastic sprouts. When villous mesenchyme invades the trophoblastic sprouts, the latter are transformed into villous sprouts. The vascularization of the villous sprouts leads to the formation of the mesenchymal villi, the most basic villous type. This process is repeated throughout pregnancy. We analyse the influence of various extracellular matrix molecules, e.g. tenascin and hyaluronic acid, on the formation of hot spots and mesenchymal villi as well as the transformation of the latter in other villous types. We present a critical survey on the data on vessel formation related to villous sprouting and morphogenesis of mesenchymal villi as well as the expression of various angiogenic factors and their receptors.

Classification of human placental stem villi: Review of structural and functional aspects

The stem villi of the human placenta represent the central branches of the villous trees. They are characterized by a condensed fibrous stroma in which the fetal arteries and veins as well as the arterioles and venules are embedded. Functionally they are accepted as the mechanically supporting structures of the villous trees, and they are supposed to control fetal blood flow to the maternofetal exchange area, which is located in the peripheral villi. To obtain further insights into the functions of the stem villi, the recent literature has been reviewed, and some immunohistochemical, ultrastructural, and reconstruction studies have been added. These new studies were aimed at identifying immunohistochemically different subtypes of stem villi, their branching patterns, the distribution of macrophages, the stromal proliferation patterns, and the differentiation of extravascular stromal cells. Our findings demonstrate that the stem villi and their precursors, the immature intermediate villi, can selectively be identified by anti-γ-smooth muscle (sm) actin staining. Furthermore, the existence of three different subtypes of stem villi is shown; these differ regarding the presence and distribution of γ-sm actin-positive cells. These cells were immunohistochemically and ultrastructurally identified as smooth muscle cells and myofibroblasts. Increasingly complex coexpression patterns of cytoskeletal proteins reflect a clearly defined differentiation gradient of extravascular stromal cells, which covers the whole range of an undifferentiated germinative layer beneath the trophoblast to highly differentiated myofibroblasts surrounding the medias of the stem vessels. Possible functions of the extravascular contractile system include the regulation of villous turgor and the control of intervillous blood flow impedance. Microsc. Res. Tech. 38:29–41, 1997. © 1997 Wiley-Liss, Inc.

Classification of human placental stem villi: review of structural and functional aspects.

The stem villi of the human placenta represent the central branches of the villous trees. They are characterized by a condensed fibrous stroma in which the fetal arteries and veins as well as the arterioles and venules are embedded. Functionally they are accepted as the mechanically supporting structures of the villous trees, and they are supposed to control fetal blood flow to the maternofetal exchange area, which is located in the peripheral villi. To obtain further insights into the functions of the stem villi, the recent literature has been reviewed, and some immunohistochemical, ultrastructural, and reconstruction studies have been added. These new studies were aimed at identifying immunohistochemically different subtypes of stem villi, their branching patterns, the distribution of macrophages, the stromal proliferation patterns, and the differentiation of extravascular stromal cells. Our findings demonstrate that the stem villi and their precursors, the immature intermediate villi, can selectively be identified by anti-gamma-smooth muscle (sm) actin staining. Furthermore, the existence of three different subtypes of stem villi is shown; these differ regarding the presence and distribution of gamma-sm actin-positive cells. These cells were immunohistochemically and ultrastructurally identified as smooth muscle cells and myofibroblasts. Increasingly complex coexpression patterns of cytoskeletal proteins reflect a clearly defined differentiation gradient of extravascular stromal cells, which covers the whole range of an undifferentiated germinative layer beneath the trophoblast to highly differentiated myofibroblasts surrounding the medias of the stem vessels. Possible functions of the extravascular contractile system include the regulation of villous turgor and the control of intervillous blood flow impedance.

Plazentareifestand „am Termin“ und funktionelle Plazentaleistung: CTG-Veränderungen in Abhängigkeit vom histologischen Nachweis plazentarer Reifungsreserven

Cardiotocography (CTG) is to be considered today's most sensitive monitoring tool for the functional surveillance of placental performance during parturition. 351 cardiotocographically monitored singleton pregnancies were used as patient material for fine tissue examination of the state of maturity of the villi of the relevant placentas. In histological assessment, placental diagnoses are allocated to defined CTG changes; in particular, however, the identification of reserves, capable of maturing (immature intermediate villi in the centres of the placental subdivisions or placentones), is subject to separate scrutiny. The following results emerge clearly: terminal placentas without maturing potentials, prematurely matured placentas and placentas with deficiency of terminal villi, as well as the absence of immature intermediate villi in the centers of the placentones, are connected with a suspected prepathological or pathological CTG assessment. The histological groups have the lowest incidence of the normal oscillatory type and normal oscillatory frequency and have the highest proportion of abnormal CTG assessments according to the Hammacher score. The absence of the identification of potential maturing reserves (immature intermediate villi) is associated with the highest incidence of Caesarean sections (29.8%). These results show, that the physiological maturing potentials (immature intermediate villi) which can be identified up to term are a histological indication towards regular placental performance, even in labour.

Immunohistochemical location of HPL, SP1 and β-HCG in normal placentas of varying gestational age

Sixty-four placentas at various gestational ages were examined by immunohistochemical stains for HPL, SP1 and beta-HCG according to a modified PAP method (Sternberger 1970). Syncytiotrophoblast cell layer was identified as the main site of synthesis. Extravillous immunohistochemical reactions for HPL and SP1 (but not for beta-HCG) were found in X-cells of the basal plate and in the intervillous trophoblast islands. These cell types would thus seem to be derived from trophoblast. Hofbauer-cells of villous connective tissue stained specifically for beta-HCG apparently because of HCG phagocytosis. The intensity of staining for HPL, SP1 and beta-HCG was evaluated semiquantitatively in the syncytiotrophoblast cell layer at various gestational weeks. The maximum of staining for beta-HCG was found in the uniform syncytiotrophoblast layer of immature intermediate villi in early pregnancy (7-14 weeks), HPL and SP1 had their peak of staining reaction at 32-36 weeks of gestation. Increasing maturation results in a subspecialisation of the villous surface: epithelial plates (allowing feto maternal exchange) and nucleated portions of syncytiotrophoblast (which are the main site of hormone production and endocrine activity).