Placental production of progestins is fully effective in villous cytotrophoblasts and increases with the syncytiotrophoblast formation.

Placental syncytiotrophoblast (ST) is considered as the main placental endocrine tissue secreting progesterone, a steroid essential for maintenance of pregnancy. However, each step of progestins production has been poorly investigated in villous cytotrophoblast (VCT) regarding ST formation. We aimed to characterize progestins production during human differentiation of VCT into ST. VCTs were isolated from term placenta and cultivated, with or without forskolin (FSK), to stimulate trophoblast differentiation. Secreted progestins concentrations were determined by immuno-assay and Gas Chromatography-tandem mass spectrometry. Intracellular expression of cholesterol transporter and enzymes involved in steroidogenesis were studied by immunofluorescence, western-blot, and RT-qPCR. Progesterone and pregnenolone are produced by VCT and their secretion increases with VCT differentiation while 17-hydroxyprogesterone concentration remains undetectable. HSD3B1 enzyme expression increases whereas MLN64, the cholesterol placental mitochondrial transporter and P450SCC expressions do not. FSK induces progestins production. Progestins placental synthesis is effective since VCT and increases with ST formation thanks to mitochondria.

Eating patterns and prevalence of obesity. Lessons learned from the Malaysian Food Barometer.

The Malaysian society is experiencing and coping with a fast modernization process, which is characterized by a rapid urbanization and rural exodus, an important reduction of the size of households, and the emergence of a new middle class. The Malaysian Food Barometer launched in 2013 has provided better understanding how these macro issues have affected the lifestyles and especially the food habits of the Malaysians. The country has indeed undergone a transition period from under-nutrition to over-nutrition in a few decades, with the prevalence of overweight and obesity having markedly and rapidly increased. A quantitative survey (n = 2000), elaborated from a qualitative preliminary phase, was carried out with the aim of analyzing the transformation of food habits at the national level. The present article focuses on the BMI issue in Malaysia, and investigates its relationships with the socio-demographic variables of the population, as well as their eating patterns. The mean BMI is 23.64 kg/m2, with 9.5% of the sample being obese, and 22% overweight. Strong statistical associations have been identified between BMI and independent variables such as size of the living area, ethnicity, level of education, gender, and age. Contrary to general believe, overweight and obesity were neither associated with the number of food intakes taken per day (including snacks) nor with the frequency of eating out. Nonetheless, obesity is over-represented in people who have dissonant eating behaviors, i.e. who declare having fewer food intakes a day (food norms) than they do actually (food practices). This process testifies that the Malaysians are experiencing a "food transition", which is linked with socio-economic development.

[Predictive and prognostic factors of preeclampsia: Interest of PlGF and sFLT-1]. / Facteurs prédictifs et pronostiques de la prééclampsie : intérêt du dosage du PlGF et du sFLT-1.

Preeclampsia is characterized by the association of hypertension and a de novo proteinuria in the second half of pregnancy. Currently, obstetrical teams do not have any tool to detect during the first trimester of pregnancy, in low risk population, the patients likely to develop early and severe preeclampsia. On the other hand, there is no diagnostic/prognostic tool in case of strong suspicion of preeclampsia. The Placental Growth Factor (PIGF) and soluble receptor of the Vascular Endothelial Growth Factor (sFlt-1) are respectively two molecules pro- and anti-angiogenic released mainly by the placenta during pregnancy. Numerous experimental and clinical results suggest that an imbalance of pro/anti-angiogenic factors is involved in the pathophysiology of preeclampsia. We selected and analyzed the main studies that have evaluated the predictive, diagnostic and prognostic value of these two biomarkers for preeclampsia.

Computational Fluid Dynamic Simulations of Maternal Circulation: Wall Shear Stress in the Human Placenta and Its Biological Implications.

INTRODUCTION: In the human placenta the maternal blood circulates in the intervillous space (IVS). The syncytiotrophoblast (STB) is in direct contact with maternal blood. The wall shear stress (WSS) exerted by the maternal blood flow on the STB has not been evaluated. Our objective was to determine the physiological WSS exerted on the surface of the STB during the third trimester of pregnancy. MATERIAL AND METHODS: To gain insight into the shear stress levels that the STB is expected to experience in vivo, we have formulated three different computational models of varying levels of complexity that reflect different physical representations of the IVS. Computations of the flow fields in all models were performed using the CFD module of the finite element code COMSOL Multiphysics 4.4. The mean velocity of maternal blood in the IVS during the third trimester was measured in vivo with dynamic MRI (0.94±0.14 mm.s-1). To investigate if the in silico results are consistent with physiological observations, we studied the cytoadhesion of human parasitized (Plasmodium falciparum) erythrocytes to primary human STB cultures, in flow conditions with different WSS values. RESULTS: The WSS applied to the STB is highly heterogeneous in the IVS. The estimated average values are relatively low (0.5±0.2 to 2.3±1.1 dyn.cm-2). The increase of WSS from 0.15 to 5 dyn.cm-2 was associated with a significant decrease of infected erythrocyte cytoadhesion. No cytoadhesion of infected erythrocytes was observed above 5 dyn.cm-2 applied for one hour. CONCLUSION: Our study provides for the first time a WSS estimation in the maternal placental circulation. In spite of high maternal blood flow rates, the average WSS applied at the surface of the chorionic villi is low (<5 dyn.cm-2). These results provide the basis for future physiologically-relevant in vitro studies of the biological effects of WSS on the STB.

Reversibility of superconducting nb weak links driven by the proximity effect in a quantum interference device.

We demonstrate the role of the proximity effect in the thermal hysteresis of superconducting constrictions. From the analysis of successive thermal instabilities in the transport characteristics of micron-size superconducting quantum interference devices with a well-controlled geometry, we obtain a complete picture of the different thermal regimes. These determine whether or not the junctions are hysteretic. Below the superconductor critical temperature, the critical current switches from a classical weak-link behavior to one driven by the proximity effect. The associated small amplitude of the critical current makes it robust with respect to the heat generation by phase slips, leading to a nonhysteretic behavior.

Review: hCGs: different sources of production, different glycoforms and functions.

Human chorionic gonadotropin (hCG) is the first hormonal message from the placenta to the mother. It is detectable in maternal blood two days after implantation and behaves like an agonist of LH stimulating progesterone secretion by the corpus luteum. hCG has also a role in quiescence of the myometrium and local immune tolerance. Specific to humans, hCG is a complex glycoprotein composed of two glycosylated subunits. The α-subunit is identical to the pituitary gonadotropin hormones (LH, FSH, TSH), contains two N-glycosylation sites, and is encoded by a single gene (CGA). By contrast the ß-subunits are distinct in each of the hormones and confer receptor and biological specificity. The hCG ß-subunit contains two sites of N-glycosylation and four sites of O-glycosylation and is encoded by a cluster of genes (CGB). In this review, we will stress the importance of hCG glycosylation state, which varies with the stage of pregnancy, its source of production and in the pathology. It is well established that hCG is mainly secreted by the syncytiotrophoblast into maternal blood where it peaks around 8-10 weeks of gestation (WG). The invasive extravillous trophoblast also secretes hCG, and in particular like choriocarcinoma cells, hyperglycosylated forms of hCG (hCG-H). In maternal blood hCG-H is high during early first trimester. In addition to its endocrine role, hCG has autocrine and paracrine roles. It promotes formation of the syncytiotrophoblast and angiogenesis through LHCG receptor. In contrast, hCG-H stimulates trophoblast invasion and angiogenesis by interacting with the TGFß receptor 2. hCG is largely used in antenatal screening and hCG-H represents a serum marker of early trophoblast invasion. Other abnormally glycosylated hCG are described in aneuploidies. In conclusion, hCG is the major pregnancy glycoprotein hormone, whose maternal concentration and glycan structure change all along pregnancy. Depending on its source of production, glycoforms of hCG display different biological activities and functions that are essential for pregnancy outcome.

Specific detection of type II human chorionic gonadotropin beta subunit produced by trophoblastic and neoplastic cells.

BACKGROUND: The sequence of the beta-subunit of human chorionic gonadotropin (hCGß) varies depending on whether hCGß is encoded by type I or type II genes. Type II genes are upregulated in trophoblast and cancer but hCGß can be detected in the serum of nonpregnant women and healthy individuals. We aimed to determine whether monoclonal antibody (mAb) FBT11-II specifically detects hCGß encoded by type II genes (type II hCGß). METHODS: Competitive inhibition assays with synthetic peptides, immunocytochemical and immunohistochemical studies, type II hCGß dosing immunoassays and sequencing of CGB genes were performed. RESULTS: Competitive inhibition assays determined that mAb FBT11-II recognizes the type II hCGß derived peptide. CGB mRNA sequencing of JEG-3 (trophoblastic) and T24 (bladder) cell lines confirmed that JEG-3 expresses type II genes while T24 expresses exclusively type I. FBT11-II only recognizes JEG-expressed hCGß. Placenta immunohistochemical studies confirmed that type II hCGß expression is restricted to the syncytiotrophoblast. Immunoassays detected type II hCGß in serum of patients with either nontrophoblastic cancers or fetal Down syndrome. CONCLUSION: Type II gene expression can be detected using FBT11-II. This specific recognition could improve the clinical usefulness of assays aimed at either managing aggressive tumors or screening for Down syndrome.

Decreased STAT3 in human idiopathic fetal growth restriction contributes to trophoblast dysfunction.

Abnormal trophoblast function is associated with fetal growth restriction (FGR). The JAK-STAT pathway is one of the principal signalling mechanisms by which cytokines and growth factors modulate cell proliferation, differentiation, cell migration and apoptosis. The expression of placental JAK-STAT genes in human idiopathic FGR is unknown. In this study, we propose the hypothesis that JAK-STAT pathway genes are differentially expressed in idiopathic FGR-affected pregnancies and contribute to abnormal feto-placental growth by modulating the expression of the amino acid transporter SNAT2, differentiation marker CGB/human chorionic gonadotrophin beta-subunit (ß-hCG) and apoptosis markers caspases 3 and 8, and TP53. Expression profiling of FGR-affected placentae revealed that mRNA levels of STAT3, STAT2 and STAT5B decreased by 69, 52 and 50%, respectively, compared with gestational-age-matched controls. Further validation by real-time PCR and immunoblotting confirmed significantly lower STAT3 mRNA and STAT3 protein (total and phosphorylated) levels in FGR placentae. STAT3 protein was localised to the syncytiotrophoblast (ST) in both FGR and control placentae. ST differentiation was modelled by in vitro differentiation of primary villous trophoblast cells from first-trimester and term placentae, and by treating choriocarcinoma-derived BeWo cells with forskolin in cell culture. Differentiation in these models was associated with increased STAT3 mRNA and protein levels. In BeWo cells treated with siRNA targeting STAT3, the mRNA and protein levels of CGB/ß-hCG, caspases 3 and 8, and TP53 were significantly increased, while that of SNAT2 was significantly decreased compared with the negative control siRNA. In conclusion, we report that decreased STAT3 expression in placentae may contribute to abnormal trophoblast function in idiopathic FGR-affected pregnancies.

hCG in screening for aneuploidy: a possible role for its glycoforms?

Fetal trisomy 21 is associated with elevated maternal serum hCG and its free beta-subunit (hCG-beta) in vivo, and abnormal placental hCG production and glycosylation in vitro. Other maternal serum markers may also be disrupted in major aneuploidies (T21, T18, T13). We evaluated our aneuploidy screening practices, focusing on hCG-beta and hCG glycoforms, and retrospectively analyzed 55 aneuploidy cases diagnosed over a 2 year period, determining maternal serum hCG glycoforms profiles using 2D-electrophoresis. Screening efficiency reached 96.7%. T21 was associated with elevated hCG-beta while T18 presented with diminished serum markers. hCG glycoforms tended to be basic in aneuploidy (mainly T13).

Homeobox genes and down-stream transcription factor PPARγ in normal and pathological human placental development.

The placenta provides critical transport functions between the maternal and fetal circulations during intrauterine development. Formation of this interface is controlled by nuclear transcription factors including homeobox genes. Here we summarize current knowledge regarding the expression and function of homeobox genes in the placenta. We also describe the identification of target transcription factors including PPARγ, biological pathways regulated by homeobox genes and their role in placental development. The role of the nuclear receptor PPARγ, ligands and target genes in human placental development is also discussed. A better understanding of these pathways will improve our knowledge of placental cell biology and has the potential to reveal new molecular targets for the early detection and diagnosis of pregnancy complications including human fetal growth restriction.

Iodide transporters expression in early human invasive trophoblast.

CONTEXT: The placenta plays an essential role in the fetomaternal exchanges of iodine and thyroid hormones. Propylthiouracil (PTU) is presently considered to be the treatment of choice for hyperthyroidism during the first trimester of pregnancy. Little is known on the expression of iodide transporters in invasive human trophoblast and the possible effect of PTU on this early phase of human placental development. OBJECTIVE: To analyze during early pregnancy expression of sodium/iodide symporter (NIS) and pendrin at the feto-maternal interface in situ in first trimester placentas, in vitro during human trophoblastic cell differentiation in presence or not of PTU. DESIGN: NIS and pendrin immunodetection were performed on 8-10 WG placental tissue sections and in primary cultures of first trimester placenta trophoblastic cells, which differentiate in vitro into syncytiotrophoblast or invasive extravillous cytotrophoblasts (EVCT). The effect of PTU (1 mM) was tested in EVCT on iodide transporters expression, cell invasion, and hCG secretion. RESULTS: NIS and pendrin were present in early human trophoblast at the maternofetal interface. Their expression was modulated with in vitro trophoblast differentiation. Early invasive EVCT were characterized by higher expression of NIS than pendrin. In vitro PTU did modify significantly neither EVCT iodide transporters expression nor EVCT biological functions: i.e. invasive properties and hCG secretion. CONCLUSION: This study reveals that NIS is highly expressed in early human trophoblast at the feto-maternal interface. PTU has no effect on early human trophoblast invasion.

Correlation of polarity and crystal structure with optoelectronic and transport properties of GaN/AlN/GaN nanowire sensors.

GaN nanowires (NWs) with an AlN insertion were studied by correlated optoelectronic and aberration-corrected scanning transmission electron microscopy (STEM) characterization on the same single NW. Using aberration-corrected annular bright field and high angle annular dark field STEM, we identify the NW growth axis to be the N-polar [000-1] direction. The electrical transport characteristics of the NWs are explained by the polarization-induced asymmetric potential profile and by the presence of an AlN/GaN shell around the GaN base of the wire. The AlN insertion blocks the electron flow through the GaN core, confining the current to the radial GaN outer shell, close to the NW sidewalls, which increases the sensitivity of the photocurrent to the environment and in particular to the presence of oxygen. The desorption of oxygen adatoms in vacuum leads to a reduction of the nonradiative surface trap density, increasing both dark current and photocurrent.

Comparative expression of hCG ß-genes in human trophoblast from early and late first-trimester placentas.

Human chorionic gonadotropin (hCG) displays a major role in pregnancy initiation and progression and is involved in trophoblast differentiation and fusion. However, the site and the type of dimeric hCG production during the first trimester of pregnancy is poorly known. At that time, trophoblastic plugs present in the uterine arteries disappear, allowing unrestricted flow of maternal blood to the intervillous space. The consequence is an important modification of the trophoblast environment, including a rise of oxygen levels from about 2.5% before 10 wk of amenorrhea (WA) to ∼8% after 12 WA. Two specific ß-hCG proteins that differ from three amino acids have been described: type 1 (CGB7) and type 2 (CGB3, -5, and -8). Here, we demonstrated in situ and ex vivo on placental villi and in vitro in primary cultures of human cytotrophoblasts that type 1 and 2 ß-hCG RNAs and proteins were expressed by trophoblasts and that these expressions were higher before blood enters in the intervillous space (8-9 vs. 12-14 WA). hCG was immunodetected in villous mononucleated cytotrophoblasts (VCT) and syncytiotrophoblast (ST) at 8-9 WA but only in ST at 12-14 WA. Furthermore, hCG secretion was fourfold higher in VCT cultures from 8-9 WA compared with 12-14 WA. Interestingly, VCT from 8-9 WA placentas were found to exhibit more fusion features. Taken together, we showed that type 1 and type 2 ß-hCG are highly expressed by VCT in the early first trimester, contributing to the high levels of hCG found in maternal serum at this term.

Vascular placental abnormalities and newborn death in a pregnant diabetic woman with familial partial lipodystrophy type 3: a possible role for peroxisome proliferator-activated receptor γ.

The peroxisome proliferator-activated receptor protein gamma (PPARγ), a nuclear receptor involved in adipocyte differentiation, energy homoeostasis and fat storage, can lead, in rare cases of coding mutations, to familial partial lipodystrophy type 3 (FPLD3) with severe insulin resistance. PPARγ is also highly expressed in the syncytiotrophoblast and extravillous cytotrophoblast cells. It has a key role in trophoblast invasion, as shown by studies in vitro, but its precise role during placentation remains to be elucidated, and fetomaternal outcomes of FPLD3 pregnancies also need to be assessed. This report is of a novel missense heterozygous mutation of PPARγ identified during pregnancy in a young diabetic woman who, at 3weeks of amenorrhoea, prematurely delivered a baby who died 24 h later. Histopathological analysis revealed important vascular placental abnormalities. The presence of the PPARγ mutation in placental tissues in the absence of fetal malformations and maternal hypertension suggests that FPLP3 pregnancies may be at high-risk, especially if the fetus has inherited the mutation. It also supports a physiological role for PPARγ during placentation.

Representations and practices of prevention in elderly populations: investigating acceptance to participate in and adhesion to an intervention study for the prevention of Alzheimer's disease (ACCEPT study)--the need for a multidisciplinary approach.

BACKGROUND: In the domain of Alzheimer's disease (AD) prevention, various potentially protective factors have been identified in epidemiological studies. Although the results of these observational studies have been relatively consistent, the results of intervention studies remain disappointing. Methodological problems could explain these negative results, like the selection of the population; a plausible assumption is that the older people who agree to take part in these intervention studies differ from those who refuse, and are those that are least likely to benefit from such programs. The aim of this study was (i) to study the determinants of participation in and adhesion to a prevention trial in a population of older individuals via a quantitative approach using a questionnaire, (ii) to study the representations and practices of prevention in this population using a qualitative approach using semi-structured interviews and focus groups. METHOD: The study population for the ACCEPT study was recruited at the time of inclusion of subjects in a prevention trial. The population was made up of persons aged 70 years or older, living at home and demonstrating some form of frailty, defined as a spontaneous memory complaint to their general practitioner or difficulties in carrying out instrumental activities of daily living. We used a quantitative approach based on the administration of a self-completed questionnaire sent to 1680 subjects having accepted to take part in the prevention trial, and to the sample of subjects meeting the inclusion criteria but having refused to take part. The qualitative approach, carried out at the moment of inclusion, involved subjects that having accepted to take part and subjects that having refused. Semi-structured interviews were carried out in order to understand the logic leading to refusal or acceptance. CONCLUSION: The analysis of the results will combine the viewpoints of the different disciplines. It will allow us to better understand the logic at work, to characterise the populations at risk of refusal, and perhaps to remove some of the barriers to participation in prevention programs. The identification of such barriers will provide feedback in terms of the conception and management of prevention measures.

Review: Human trophoblast fusion and differentiation: lessons from trisomy 21 placenta.

The syncytiotrophoblast layer plays a major role throughout pregnancy, since it is the site of numerous placental functions, including ion and nutrient exchange and the synthesis of steroid and peptide hormones required for fetal growth and development. Inadequate formation and regeneration of this tissue contributes to several pathologies of pregnancy such as intrauterine growth restriction and preeclampsia, which may lead to iatrogenic preterm delivery in order to prevent fetal death and maternal complications. Syncytiotrophoblast formation can be reproduced in vitro using different models. For the last ten years we have routinely purified villous cytotrophoblastic cells (CT) from normal first, second and third trimester placentas and from gestational age-matched Trisomy 21 placentas. We cultured villous CT on plastic dishes to follow the molecular and biochemical aspects of their morphological and functional differentiation. Taking advantage of this unique collection of samples, we here discuss the concept that trophoblast fusion and functional differentiation may be two differentially regulated processes, which are linked but quite distinct. We highlight the major role of mesenchymal-trophoblast cross talk in regulating trophoblast cell fusion. We suggest that the oxidative status of the trophoblast may regulate glycosylation of proteins, including hCG, and thereby modulate major trophoblast cell functions.

Expression and localization of DLX3, PPARG and SP1 in bovine trophoblast during binucleated cell differentiation.

The differentiation of the trophoblast is marked in ruminants by the formation of binucleated cells (BNC). They appear from pre-implantation onwards but the molecular mechanisms underlying their differentiation remain largely unexplored. Taking advantage of our recent data, we analyzed the expression pattern of DLX3 and PPARG that are known regulators of early placenta formation and extended our analysis to one of their potential regulators, SP1. Our study is the first to demonstrate the co-expression of DLX3, PPARG and SP1 in bovine BNC nuclei. This suggests a possible role of these transcription factors through BNC specific genes at the time of pre-placental differentiation.

The THEMA study: a sociodemographic survey of hypercholesterolaemic individuals.

BACKGROUND: Hypercholesterolaemia is estimated to affect 20% of the population, although little sociodemographic information is available on affected individuals. The present study aimed to gather relevant information and investigate social determinants of dietary compliance. METHODS: A telephone survey was carried out on a representative population sample. Quotas were applied for gender, geography and degree of urbanisation. Individuals were eligible if they were hypercholesterolaemic, and were being followed by a doctor. Sociodemographic, socioeconomic and health data were collected, as well as information about the individuals' perception of the disease, their relationship and beliefs surrounding food, and their food behaviour (shopping, cooking, eating-out, deviation from prescribed diet). The association between compliance with diet and medication was investigated. RESULTS: Overall, 802 individuals were included, representing 8% of those contacted, as opposed to the expected 20%. Mean (SD) age was 60 (14.2) years, with 51% of individuals living as a couple; 48% had a good level of physical activity; 44% considered that the hypercholesterolaemia was inherited; 31% felt that the disease was normal beyond the age of 45 years. The functional and convivial aspects of eating were of more importance than that of health maintenance. Cheese was particularly likely to be eaten in dietary lapses. Of a subgroup of 729 individuals, 476 (65%) took medication; of these 476 individuals, 51% complied with dietary recommendations (P < 0.05). CONCLUSIONS: The key factors associated with dietary compliance in hypercholesterolaemic individuals were identified: age, sex, the perceptions of hypercholesterolaemia, and the sociocultural aspects of food. By contrast to general assumptions, both dietary and medicinal measures are practised fairly well by a large proportion of these individuals.

IFPA Meeting 2010 Workshops Report II: Placental pathology; trophoblast invasion; fetal sex; parasites and the placenta; decidua and embryonic or fetal loss; trophoblast differentiation and syncytialisation.

Workshops are an important part of the IFPA annual meeting. At IFPA Meeting 2010 diverse topics were discussed in twelve themed workshops, six of which are summarized in this report. 1. The placental pathology workshop focused on clinical correlates of placenta accreta/percreta. 2. Mechanisms of regulation of trophoblast invasion and spiral artery remodeling were discussed in the trophoblast invasion workshop. 3. The fetal sex and intrauterine stress workshop explored recent work on placental sex differences and discussed them in the context of whether boys live dangerously in the womb.4. The workshop on parasites addressed inflammatory responses as a sign of interaction between placental tissue and parasites. 5. The decidua and embryonic/fetal loss workshop focused on key regulatory mediators in the decidua, embryo and fetus and how alterations in expression may contribute to different diseases and adverse conditions of pregnancy. 6. The trophoblast differentiation and syncytialisation workshop addressed the regulation of villous cytotrophoblast differentiation and how variations may lead to placental dysfunction and pregnancy complications.

Hyperglycosylated hCG is a marker of early human trophoblast invasion.

CONTEXT: Human chorionic gonadotropin (hCG) is the major pregnancy glycoprotein hormone whose maternal concentration and glycan structure change all along pregnancy. hCG is mainly secreted by the syncytiotrophoblast covering the chorionic villi, but little is known about the source of hyperglycosylated hCG (hCG-H) production. OBJECTIVE: The objective of the study was to analyze expression and secretion of hCG and hCG-H in vitro during human trophoblastic cell differentiation, in situ in first-trimester placentas, and in maternal sera during early pregnancy. DESIGN: hCG and hCG-H were measured in cell supernatants from primary cultures of first-trimester placenta trophoblastic cells, which differentiate in vitro into syncytiotrophoblast or invasive extravillous cytotrophoblasts (evct). hCG-H immunodetection were performed on 9 wk gestation (WG) placental tissue sections. Total hCG and hCG-H were quantified by chemiluminometric assay in 539 maternal sera collected between 9 and 19 WG during normal pregnancies. RESULTS: In vitro, hCG secretion reached 37 ng/ml per µg DNA during syncytiotrophoblast formation but contained few hCG-H (2-5% of total hCG). In contrast, hCG secretion (20 ng/ml per µg DNA) in evct supernatants contained 10-20% hCG-H. In situ, hCG-H immunostaining was strong in invasive and endovascular evct, weaker in mononucleated villous cytotrophoblasts, but negative in the syncytiotrophoblast. In maternal sera, hCG-H concentrations continuously decreased during pregnancy from 406 ± 222 ng/ml at 9 WG to 8 ± 6 ng/ml at 19 WG, whereas total hCG picked up at 11 WG and then decreased. CONCLUSIONS: This study suggests that the high levels of hCG-H observed in first-trimester maternal sera are mainly from invasive evct origin, reflecting the early trophoblast invasion process.