PLAC8, a new marker for human interstitial extravillous trophoblast cells, promotes their invasion and migration.

Proper differentiation of trophoblast cells in the human placenta is a prerequisite for a successful pregnancy, and dysregulation of this process may lead to malignant pregnancy outcomes, such as preeclampsia. Finding specific markers for different types of trophoblast cells is essential for understanding trophoblast differentiation. Here, we report that placenta-specific protein 8 (PLAC8) is specifically expressed in the interstitial extravillous trophoblast cells (iEVTs) on the fetomaternal interface. Using model systems, including placental villi-decidua co-culture, iEVTs induction by using primary trophoblast cells or explants, etc., we found that PLAC8 promotes invasion and migration of iEVTs. Mechanistically, time-lapse imaging, GTPase activity assay, co-immunoprecipitation and RNA-seq studies show that PLAC8 increases the Cdc42 and Rac1 activities, and further induces the formation of filopodia at the leading edge of the migratory trophoblast cells. More interestingly, PLAC8 is significantly upregulated under hypoxia and expression of PLAC8 is higher in iEVTs from preeclamptic placentas when compared with those from the normal control placentas. Together, PLAC8 is a new marker for iEVTs and plays an important role in promoting trophoblast invasion and migration.

A multiscale model of placental oxygen exchange: The effect of villous tree structure on exchange efficiency.

The placenta is critical to fetal health during pregnancy as it supplies oxygen and nutrients to maintain life. It has a complex structure, and alterations to this structure across spatial scales are associated with several pregnancy complications, including intrauterine growth restriction (IUGR). The relationship between placental structure and its efficiency as an oxygen exchanger is not well understood in normal or pathological pregnancies. Here we present a computational framework that predicts oxygen transport in the placenta which accounts for blood and oxygen transport in the space around a placental functional unit (the villous tree). The model includes the well-defined branching structure of the largest villous tree branches, as well as a smoothed representation of the small terminal villi that comprise the placenta's gas exchange interfaces. The model demonstrates that oxygen exchange is sensitive to villous tree geometry, including the villous branch length and volume, which are seen to change in IUGR. This is because, to be an efficient exchanger, the architecture of the villous tree must provide a balance between maximising the surface area available for exchange, and the opposing condition of allowing sufficient maternal blood flow to penetrate into the space surrounding the tree. The model also predicts an optimum oxygen exchange when the branch angle is 24 °, as villous branches and TBs are spread out sufficiently to channel maternal blood flow deep into the placental tissue for oxygen exchange without being shunted directly into the DVs. Without concurrent change in the branch length and angles, the model predicts that the number of branching generations has a small influence on oxygen exchange. The modelling framework is presented in 2D for simplicity but is extendible to 3D or to incorporate the high-resolution imaging data that is currently evolving to better quantify placental structure.

Caspase-mediated apoptosis of trophoblasts in term human placental villi is restricted to cytotrophoblasts and absent from the multinucleated syncytiotrophoblast.

Human placental villi are surfaced by a multinucleated and terminally differentiated epithelium, the syncytiotrophoblast, with a subjacent layer of mononucleated cytotrophoblasts that can divide and fuse to replenish the syncytiotrophoblast. The objectives of this study were i) to develop an approach to definitively identify and distinguish cytotrophoblasts from the syncytiotrophoblast, ii) to unambiguously determine the relative susceptibility of villous cytotrophoblasts and syncytiotrophoblast to constitutive and stress-induced apoptosis mediated by caspases, and iii) to understand the progression of apoptosis in villous trophoblasts. Confocal microscopy with co-staining for E-cadherin and DNA allowed us to clearly distinguish the syncytiotrophoblast from cytotrophoblasts and identified that many cytotrophoblasts are deeply interdigitated into the syncytiotrophoblast. Staining for specific markers of caspase-mediated apoptosis indicate that apoptosis occurs readily in cytotrophoblasts but is remarkably inhibited in the syncytiotrophoblast. To determine if an apoptotic cell or cell fragment was from a cytotrophoblast or syncytiotrophoblast, we found co-staining with E-cadherin along with a marker for apoptosis was essential: in the absence of E-cadherin staining, apoptotic cytotrophoblasts would easily be mistaken as representing localized regions of apoptosis in the syncytiotrophoblast. Regions with perivillous fibrin-containing fibrinoid contain the remnants of trophoblast apoptosis, and we propose this apoptosis occurs only after physical isolation of a region of the syncytium from the main body of the syncytium. We propose models for the progression of apoptosis in villous cytotrophoblasts and for why caspase-mediated apoptosis does not occur within the syncytium of placental villi.

The emerging roles of placenta-specific microRNAs in regulating trophoblast proliferation during the first trimester.

In the human placenta, eight 'placenta-specific' microRNAs (miRNAs) are exclusively expressed and are associated with high cloning frequencies. The expression of placenta-specific miRNAs is known to be involved in preeclampsia, but the understanding of these miRNAs is still limited. The goal of this study was to investigate the levels and localisations of eight placenta-specific miRNAs in placental villi with different proliferative abilities during the first trimester. Immunohistochemical analyses indicated that placental trophoblast proliferation ability was associated with the weight of villi in the same gestational week during the first trimester. Of the eight placenta-specific miRNAs, quantitative real-time RT-PCR demonstrated that the expression of miR-517b and miR-1283 was increased in the lightest villi and decreased in the heaviest one, the expression of miR-519a was increased in the heaviest villi and decreased in the lightest one. In situ hybridisation analysis showed that miR-517b and miR-519a were located primarily in the trophoblast layer, while miR-1283 were expressed not only in the villous trophoblasts but also in some villous stroma cells. These findings suggest that miR-517b and miR-519a may play an important role in trophoblast proliferation during the first trimester.

[Anchoring villi are sources of cytotrophoblastic invasion in the second trimester of physiologic pregnancy].

The basal laminas and fixed on them anchoring villi after late abortion on 18-28 weeks of pregnancy have been studied. The pregnancies were without complication and abortions were activated by "Enzaprost" injection. 4 types of anchoring villi were studied: without cytotrophoblastic invasion, with maximal, medium and minimal density of cytotrophoblastic distribution and depth of its invasion into endometrium from villi's base. The maximum of its migration activity was in 18-20 and 22-23 weeks of pregnancy. The activity decay of cytotrophoblastic invasion was been found in the end of the second trimester Anatomic contact of villi's base with endometrium increased by them parallel attachment or horseshoe-shaped form. The estimation of villi's quantity and density of cytotrophoblastic distribution in their base can use for definition of cytotrophoblastic invasion rate in the adjacent myometrium of pregnant women on the second trimester.

Placental stem cell differentiation into islets of Langerhans-like glucagon-secreting cells.

BACKGROUND AND PURPOSE: For the past few years, in an attempt to find new sources of cells that may be used in cell therapy, numerous researchers have highlighted the particular properties of mesenchymal stem cells. Mesenchymal stem cells can be isolated from adult tissues such as the bone marrow or adipose tissue, but also from other organs such as the human placenta. Our study focuses adult stem cells isolated from the chorionic villi in an attempt to differentiate them into islets of Langerhans in order to study their differentiation potential, as a future background for cell therapy. EXPERIMENTAL DESIGN: Full-term placentas were prelevated from volunteer women that have just delivered a normal pregnancy. After a mechanical fragmentation of the placenta, the chorion fragments are transferred in a dish with dispase before the enzyme is inactivated using fetal calf serum. The cell suspension is filtered in order to obtain a single-cell suspension. After the adherence of the first cells, the proliferation rate increased progressively and cell morphology is kept the same for several passages. In order to correctly differentiate placental stem cells into glucagon-secreting cells, we used a culture method on a scaffold with sequential exposure to different growth factors. The underlying substrate used contained type IV collagen, chytosan, Matrigel and laminin. Molecular biology techniques were carried out to investigate the gene expression of the stem cells. RESULTS: Our results show that exendin-4 is able to induce the differentiation of placental stem cells into glucagon-secreting cells. We also notice the absence of the insulin gene, a conclusion that may be explained by the fact that our phenotype is a partial one, incomplete, closer to islet cell progenitors than to insulin-producing progenitors. CONCLUSIONS: The identification of the placenta as a valid source for stem cells has important practical advantages because it is easily accessible, it raises no ethical issues and cells are easily to isolate in a large enough number to use. The future knowledge and manipulation of the signaling pathways that determines the dramatic phenotype shift may provide the basis for efficient cell differentiation, with great impact on regenerative medicine and tissue engineering.

The volume of villi with γ-sm-actin positive perivascular cells correlates with placental weight and thickness.

INTRODUCTION: The classification of histologically stained villous cross sections in villous types (terminal, intermediate and stem villi) by stromal peculiarities is known to be observer predicated. Therefore, quantitative histology of villous trees has not become a routine endpoint of studies on the role of the placenta in prenatal programming, as opposed to the gross placental parameters weight and thickness. The classification of villous cross sections in central (stem) and peripheral (terminal) parts based on the presence or absence, respectively, of immunohistochemical detection of myofibroblasts in perivascular position is less observer dependent. We hypothesized that it will, possibly, identify microscopic correlates of placental weight and thickness within the villous tree. METHODS: 50 placentas from clinically normal pregnancies were processed for the present study. Thin villous cross sections, obtained in a systematic random manner, were stained immunohistochemically to detect γ-smooth muscle (sm) actin and to classify them subsequently as part of central or peripheral villous tree. The volume fractions of histological structures visible in villous cross sections (stroma, lumen, endothelium and syncytium) were estimated by design-based stereology. RESULTS: The present study reveals a significant correlation of placental weight and thickness with the volume estimate of stroma that have myofibroblasts in perivascular position. DISCUSSION: The positive linear correlation between the volume of central parts of villous trees and the placental weight and thickness is new. Surprisingly, the volume of more peripheral parts of villous trees, which is the main site of materno-fetal exchange does not correlate with placental weight and thickness.

Stereological Analysis of Adolescent Placentas and Anthropometric Characteristics of Newborns.

INTRODUCTION: Knowledge of the size of surfaces available for transport is important for assessing the amount of nutrients that can be transmitted to the fetus for its normal growth and development. AIM: The aim of our study, was to determine the stereological structural parameters of the parenchymal part of placenta, ratio of birth weight and placental weight, and to determine their correlation with the body length and head circumference of the newborns of adolescent pregnant women. METHODS: The study was conducted on a total of 60 human placentas of term pregnancy, divided into two groups according to the age of pregnant women. The experimental group consisted of 30 placenta of pregnant women aged 13-19. The control group consisted of 30 placenta of pregnant women aged 20-35. Computer assisted morphological analysis of images of histological preparations using stereological methods was performed. RESULTS: Surface density of terminal villi of adolescent placentas is significant higher than the control group (t = 14,179, df = 29, p <0,0001). The T-test (t = -5,868, df = 29, p <0,0001) showed statistically significant difference in the surface density of fibrinoid in two compared groups. T-test (t = 6.438, df = 29, p <0.0001) found that total surface of terminal villi was significantly higher in adolescent placentas. The T-test (t = -6,747, df = 29, p <0,0001) found that total surface of fibrinoid was significantly lower in adolescent group. The T-test (t = 4.203, df = 29, p <0.0001) found that the ratio of birth weight of newborn and adolescent placental weight was significantly higher in relation to the control group. CONCLUSION: Adolescent placentas was more efficient in increasing the weight of newborns, compared to the control group placentas.

Clarification and confocal imaging of the nonhuman primate placental micro-anatomy.

Geometry of the placental villous vasculature is a key determinant of maternal-fetal nutrient exchange for optimal fetal growth. Recent advances in tissue clarification techniques allow for deep high-resolution imaging with confocal microscopy; however, the methodology lacks a signal:noise ratio of sufficient magnitude to allow for quantitative analysis. Thus, we sought to develop a reproducible method to investigate the 3D vasculature of the nonhuman primate placenta for subsequent data analysis. Fresh placental tissue was dissected, formalin fixed, clarified using a modified Visikol® protocol and immunolabeled for CD31 (fetal endothelium) and cytokeratin-7 (villous trophoblast) for confocal imaging of the microanatomy. We present a detailed clarification and staining protocol augmented for imaging of nonhuman primate placental tissue. The image stacks generated by this refined staining method and our data acquisition parameters can be analyzed quantitatively to provide insights regarding the villous and vascular micro-anatomy of the placenta.

Trypanosoma cruzi (Chagas' disease agent) reduces HIV-1 replication in human placenta.

BACKGROUND: Several factors determine the risk of HIV mother-to-child transmission (MTCT), such as coinfections in placentas from HIV-1 positive mothers with other pathogens. Chagas' disease is one of the most endemic zoonoses in Latin America, caused by the protozoan Trypanosoma cruzi. The purpose of the study was to determine whether T. cruzi modifies HIV infection of the placenta at the tissue or cellular level. RESULTS: Simple and double infections were carried out on a placental histoculture system (chorionic villi isolated from term placentas from HIV and Chagas negative mothers) and on the choriocarcinoma BeWo cell line. Trypomastigotes of T. cruzi (VD lethal strain), either purified from mouse blood or from Vero cell cultures, 24 h-supernatants of blood and cellular trypomastigotes, and the VSV-G pseudotyped HIV-1 reporter virus were used for the coinfections. Viral transduction was evaluated by quantification of luciferase activity. Coinfection with whole trypomastigotes, either from mouse blood or from cell cultures, decreased viral pseudotype luciferase activity in placental histocultures. Similar results were obtained from BeWo cells. Supernatants of stimulated histocultures were used for the simultaneous determination of 29 cytokines and chemokines with the Luminex technology. In histocultures infected with trypomastigotes, as well as in coinfected tissues, IL-6, IL-8, IP-10 and MCP-1 production was significantly lower than in controls or HIV-1 transducted tissue. A similar decrease was observed in histocultures treated with 24 h-supernatants of blood trypomastigotes, but not in coinfected tissues. CONCLUSION: Our results demonstrated that the presence of an intracellular pathogen, such as T. cruzi, is able to impair HIV-1 transduction in an in vitro system of human placental histoculture. Direct effects of the parasite on cellular structures as well as on cellular/viral proteins essential for HIV-1 replication might influence viral transduction in this model. Nonetheless, additional mechanisms including modulation of cytokines/chemokines at placental level could not be excluded in the inhibition observed. Further experiments need to be conducted in order to elucidate the mechanism(s) involved in this phenomenon. Therefore, coinfection with T. cruzi may have a deleterious effect on HIV-1 transduction and thus could play an important role in viral outcome at the placental level.

Immunohistochemical identification of the extravillous trophoblast during the placentation of the degu (Octodon degus).

Recent data indicate that placentation in Octodon degus is similar to that in humans, making it a potential animal model for studies in human placental pathologies related to alterations in the migration of the extravillous trophoblast (EVT). Our objective was to immunohistochemically identify degu EVT during placentation by using cytoskeletal protein markers to establish the normal migratory pattern of the EVT. Fifteen O.degus were divided into three equal groups: day 27, 60, and 84 of gestation. The placentas were immunostained for cytokeratin (CK) and alpha smooth muscle actin (SMA). At day 27, the migrating EVT immunostained for SMA but not for CK. Once the EVT was incorporated in the maternal vessels (day 60) it was positive for CK but negative for SMA. The smooth muscle cells of the mesometrial arteries that remained after EVT invasion were positive for SMA. At day 84, the media muscular layer had partially regenerated but some EVT was still present. Furthermore, at day 27 cyclooxygenase-1 (COX-1) was detected in the endothelium of the maternal decidual vessels. Our results suggest that during the early stages of placentation, the cytoskeletal organization of the actin network of the migrating EVT corresponds to that of a cell with motile behavior. Once the EVT invaded the spiral arteries, the cytoskeleton reorganized, adopting the structure of an epithelial-like cell, expressing CK intermediate filaments. The media muscle layer regenerated near the end of gestation but some EVT remained. During EVT formation the endothelium of the maternal decidual vessels immunostained for COX-1.

Distribution patterns of extracellular matrix components and adhesion receptors are intricately modulated during first trimester cytotrophoblast differentiation along the invasive pathway, in vivo.

Development of the human embryo depends on the ability of first trimester cytotrophoblastic stem cells to differentiate and invade the uterus. In this process, transient expression of an invasive phenotype is part of normal cytotrophoblast differentiation. Morphologically, this process begins when polarized chorionic villus cytotrophoblasts form multilayered columns of nonpolarized cells, and invade the uterus. Using immunocytochemistry, we compared the presence of adhesion receptors and extracellular matrix ligands on cytotrophoblasts in villi, cell columns, and the uterine wall. Villus cytotrophoblasts, anchored to basement membrane, stained for alpha 6 and beta 4 integrin subunits and both merosin and A-chain-containing laminin. Nonpolarized cytotrophoblasts in columns expressed primarily alpha 5 and beta 1 integrin subunits and a fibronectin-rich matrix. Cytotrophoblast clusters in the uterine wall stained for alpha 1, alpha 5, and beta 1 integrins, but not for most extracellular matrix antigens, suggesting that they interact primarily with maternal cells and matrices. Tenascin staining was restricted to stroma at sites of transition in cytotrophoblast morphology, suggesting that tenascin influences cytotrophoblast differentiation. Our results suggest that regulation of adhesion molecule expression contributes to acquisition of an invasive phenotype by cytotrophoblasts and provide a foundation for studying pathological conditions in which insufficient or excessive trophoblast invasion occurs, such as preeclampsia or choriocarcinoma.

Purinergic receptor expression and activation in first trimester and term human placenta.

Intracellular calcium concentration ([Ca(2+)](i)) is an important signalling molecule in the human placenta and regulation of [Ca(2+)](i) must be tightly controlled to ensure normal cell function and in order to meet the changing demand for calcium with increased fetal growth over gestation. Little is known about the receptors and mechanisms involved in intracellular calcium signalling in the human placenta but in isolated cytotrophoblast cells members of the P2 purinergic receptor family have been shown to mediate an ATP-stimulated rise in [Ca(2+)](i). In this study we examined activation and expression of several of the purinergic receptor subtypes in human placental villous fragments at two stages of gestation, first trimester and term. We demonstrate mRNA and protein expression of the P2X(4), P2X(7) and P2Y(2) subtypes but found no evidence of P2Y(4) protein in the placenta. Using fluorescent calcium imaging we demonstrate that 300 microM ATP, 450 microM UTP and 300 microM BzATP significantly elevate [Ca(2+)](i) in villous fragments with a significant increase in agonist-induced response seen in the term compared to the first trimester fragments (ATP, P<0.0001; UTP, P=0.018; BzATP, P=0.015). The roles of the purinergic receptors within the human placenta are not known but it seems likely for this study that calcium handling through these receptors is altered with advancing gestation. This may be due to the need to meet increased fetal Ca(2+) requirements due to growth or as a secondary function to alterations in placental [Ca(2+)](i) signalling.

Tumour necrosis factor-alpha stimulates HIV-1 replication in single-cycle infection of human term placental villi fragments in a time, viral dose and envelope dependent manner.

BACKGROUND: The placenta plays an important role in the control of in utero HIV-1 mother-to-child transmission (MTCT). Proinflammatory cytokines in the placental environment are particularly implicated in this control. We thus investigated the effect of TNF-alpha on HIV-1 expression in human placental tissues in vitro. RESULTS: Human placental chorionic villi fragments were infected with varying doses of luciferase reporter HIV-1 pseudotypes with the R5, X4-Env or the vesicular stomatitis virus protein G (VSV-G). Histocultures were then performed in the presence or absence of recombinant human TNF-alpha. Luciferase activity was measured at different time points in cell lysates or on whole fragments using ex vivo imaging systems.A significant increase in viral expression was detected in placental fragments infected with 0.2 ng of p24 antigen/fragment (P = 0.002) of VSV-G pseudotyped HIV-1 in the presence of TNF-alpha seen after 120 hours of culture. A time independent significant increase of viral expression by TNF-alpha was observed with higher doses of VSV-G pseudotyped HIV-1. When placental fragments were infected with R5-Env pseudotyped HIV-1, a low level of HIV expression at 168 hours of culture was detected for 3 of the 5 placentas tested, with no statistically significant enhancement by TNF-alpha. Infection with X4-Env pseudotyped HIV-1 did not lead to any detectable luciferase activity at any time point in the absence or in the presence of TNF-alpha. CONCLUSION: TNF-alpha in the placental environment increases HIV-1 expression and could facilitate MTCT of HIV-1, particularly in an inflammatory context.

Stereological analysis of mature human placenta of pregnant women of different age.

The normal placentas, regular pregnancies and deliveries were structurally examined. The aim of this research was to compare the results and to confirm if there were some difference in the structure of placenta related to the age of pregnant women. We examined 30 human placentas. The examined group of women were divided into two groups: 1) pregnant women 20-35 years old; 2) pregnant women over 35 years old. The stereological method was used. The volume density, absolute volume, the surface density and absolute surface of terminal villi of placentas in younger and older pregnant women were not significantly different. The volume density, absolute volume, the surface density and absolute surface of the other placentas villi in younger pregnant women compared to older ones, were significantly increased (p<0.001). The volume density of fibrinoid of placentas in older pregnant women compared to younger ones was significantly increased (p<0.02). The surface density, absolute volume and absolute surface of fibrinoid in these two examined groups of pregnant women were not significantly different. The volume density of intervillous space of placentas in older pregnant women compared to younger ones was significantly increased (p<0.05). Absolute volumes of intervillous space of placentas in these two examined groups of pregnant women are not significantly different.

Villus packing density and lacunarity: Markers of placental efficiency?

We evaluate, in routine H&E histology slides, villus quantity in a given area (villous packing density, VPD) and the pattern or "gappiness" of villous distribution (lacunarity), and test for correlations with a proxy for fetoplacental metabolic rate, ß calculated as (ln (placental weight)/ln (birthweight)) from Kleiber's law [1]. Three ∼4.3 mm2 images each were obtained from 88 term placentas. Ranges of VPD and lacunarity were each correlated with ß (r = 0.31, p = 0.003, r = 0.23, p = 0.03 and respectively). The relationship between ß and within-placenta variation in VPD and lacunarity highlights the need to study not merely the mean but the variance of villous geometries and spatial distributions.

Differential expression of toll-like receptors in the human placenta across early gestation.

Toll-like receptors (TLRs) are an essential component of the innate immune system. While a number of studies have described TLR expression in the female reproductive tract, few have examined the temporal expression of TLRs within the human placenta. We hypothesized that the pattern of TLR expression in the placenta changes throughout the first and second trimester, coincident with physiological changes in placental function and the demands of innate immunity. We collected first and second trimester placental tissue and conducted quantitative PCR analysis for TLRs 1-10, followed by immunohistochemistry to define the cell specific expression pattern of a subset of these receptors. Except for the very earliest time points, RNA expression for TLRs 1-10 was stable out to 20 weeks gestation. However, the pattern of protein expression evolved over time. Early first trimester placenta demonstrated a strong, uniform pattern predominantly in the inner villous cytotrophoblast layer. As the placenta matured through the second trimester, both the villous cytotrophoblasts and the pattern of TLR expression within them became disorganized and patchy, with putative Hofbauer cells now identifiable in the tissue also staining positive. We conclude from this data that placental TLR expression changes over the course of gestation, with a tight barrier of TLRs forming a wall of defense along the cytotrophoblast layer in the early first trimester that breaks down as pregnancy progresses. These data are relevant to understanding placental immunity against pathogen exposure throughout pregnancy and may aid in our understanding of the vulnerable period for fetal exposure to pathogens.

Three-dimensional modeling of human placental terminal villi.

INTRODUCTION: Placental transport is the main factor affecting the health and development of the fetus. Due to the placenta's geometrical and mathematical complexity, the structure-function relations of placental terminal villi have not been successfully modeled. Hence, a novel modeling approach is proposed. METHODS: Computational models of four different specimens were generated from the three-dimensional reconstruction of confocal laser scanning microscopic image stacks. To evaluate the capabilities of the proposed methodology, stationary oxygen diffusion transport was calculated in the terminal villus volumes. RESULTS: The reconstructions automatically provided the spatial arrangement of the fetal capillaries inside the terminal villi. The surface and volume ratios between the fetal capillaries and the villus were also calculated, and the effects of model parameters on the placental diffusive capacity were assessed by parametric analysis. DISCUSSION: The potential of three-dimensional reconstructions combined with finite element analysis as a research tool for the human placenta was tested. The methodology herein could serve in the future as a simulation platform for complicated in vivo and in vitro scenarios.

Pattern of adhesive molecules expression in placenta of non-complicated ART pregnancies.

OBJECTIVE: To investigate changes occurring in the morphometric parameters of chorionic villi and their vessels as well as in adhesive molecules expression in placenta of ART pregnancies. METHODS: Case-control study including a total of 52 placentas of non-complicated pregnancies of women delivered by spontaneous conception (SC) (n = 26) compared with those of ART (n = 26). Histological and morphometric assessment of fetal chorionic villi as well as the expression of various adhesive molecules (ICAM-1, VCAM-1 and PECAM-1) were performed in fetal plasma and placenta. RESULTS: Although we did not observe any obvious changes in the histological structure of placenta of ART pregnancies, it showed a significant (p < 0.05) decrease in the syncytiotrophoblast cytoplasmic area accompanied with a significant increase (p < 0.05) in the vessel area and syncytiotrophoblast nuclear area without remarkable change in the total villous area or total syncytiotrophoblast % area. In addition, almost all levels of the assayed adhesive molecules were significantly increased (p < 0.05) in placenta as well as in fetal plasma of ART pregnancies compared with SC. CONCLUSION: We suggested in the current study that the altered adhesive molecules expression accompanying the increased vessel area and decreased syncytial cytoplasm area may indicate a subclinical endothelial stress in placenta of non-complicated ART pregnancies.

Novel 3D light microscopic analysis of IUGR placentas points to a morphological correlate of compensated ischemic placental disease in humans.

The villous tree of the human placenta is a complex three-dimensional (3D) structure with branches and nodes at the feto-maternal border in the key area of gas and nutrient exchange. Recently we introduced a novel, computer-assisted 3D light microscopic method that enables 3D topological analysis of branching patterns of the human placental villous tree. In the present study we applied this novel method to the 3D architecture of peripheral villous trees of placentas from patients with intrauterine growth retardation (IUGR placentas), a severe obstetric syndrome. We found that the mean branching angle of branches in terminal positions of the villous trees was significantly different statistically between IUGR placentas and clinically normal placentas. Furthermore, the mean tortuosity of branches of villous trees in directly preterminal positions was significantly different statistically between IUGR placentas and clinically normal placentas. We show that these differences can be interpreted as consequences of morphological adaptation of villous trees between IUGR placentas and clinically normal placentas, and may have important consequences for the understanding of the morphological correlates of the efficiency of the placental villous tree and their influence on fetal development.