Trophoblast origin of hCG isoforms: cytotrophoblasts are the primary source of choriocarcinoma-like hCG

Associations of Serum Perfluoroalkyl Substances and Placental Human Chorionic Gonadotropin in Early Pregnancy, Measured in the UPSIDE Study in Rochester, New York

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widely detected in pregnant women and associated with adverse outcomes related to impaired placental function. Human chorionic gonadotropin (hCG) is a dimeric glycoprotein hormone that can indicate placental toxicity.

OBJECTIVES

Our aim was to quantify the association of serum PFAS with placental hCG, measured as an intact molecule (hCG), as free alpha-(hCG α ) and beta-subunits (hCG β ), and as a hyperglycosylated form (h-hCG), and evaluate effect measure modification by social determinants and by fetal sex.

METHODS

Data were collected from 326 pregnant women enrolled from 2015 to 2019 in the UPSIDE study in Rochester, New York. hCG forms were normalized for gestational age at the time of blood draw in the first trimester [multiple of the median (MoM)]. Seven PFAS were measured in second-trimester maternal serum. Multivariate imputation by chained equations and inverse probability weighting were used to evaluate robustness of linear associations. PFAS mixture effects were estimated by Bayesian kernel machine regression.

RESULTS

Perfluorohexane sulfonic acid (PFHxS) [hCG β : 0.29 log MoM units per log PFHxS; 95% confidence interval (CI): 0.08, 0.51] and perfluorodecanoic acid (PFDA) (hCG: - 0.09 ; 95% CI: - 0.16 , - 0.02 ) were associated with hCG in the single chemical and mixture analyses. The PFAS mixture was negatively associated with hCG α and positively with hCG β . Subgroup analyses revealed that PFAS associations with hCG differed by maternal race/ethnicity and education. Perfluoropentanoic acid (PFPeA) was associated with hCG β only in Black participants (- 0.23 ; 95% CI: - 0.37 , - 0.09 ) and in participants with high school education or less (- 0.14 ; 95% CI: - 0.26 , - 0.02 ); conversely, perfluorononanoic acid (PFNA) was negatively associated with hCG α only in White participants (- 0.15 ; 95% CI: - 0.27 , - 0.03 ) and with hCG β only in participants with a college education or greater (- 0.19 ; 95% CI: - 0.36 , - 0.01 ). These findings were robust to testing for selection bias, confounding bias, and left truncation bias where PFAS detection frequency was < 100 % . Two associations were negative in male (and null in female) pregnancies: Perfluoroundecanoic acid (PFUnDA) with hCG α , and PFNA with h-hCG.

CONCLUSIONS

Evidence was strongest for the association between PFHxS and PFDA with hCG in all participants and for PFPeA and PFNA within subgroups defined by social determinants and fetal sex. PFAS mixture associations with hCG α and hCG β differed, suggesting subunit-specific types of toxicity and/or regulation. Future studies will evaluate the biological, clinical and public health significance of these findings. https://doi.org/10.1289/EHP12950.

Molecular pathways in placental-fetal development and disruption

The first trimester of pregnancy ranks high in priority when minimizing harmful exposures, given the wide-ranging types of organogenesis occurring between 4- and 12-weeks' gestation. One way to quantify potential harm to the fetus in the first trimester is to measure a corollary effect on the placenta. Placental biomarkers are widely present in maternal circulation, cord blood, and placental tissue biopsied at birth or at the time of pregnancy termination. Here we evaluate ten diverse pathways involving molecules expressed in the first trimester human placenta based on their relevance to normal fetal development and to the hypothesis of placental-fetal endocrine disruption (perturbation in development that results in abnormal endocrine function in the offspring), namely: human chorionic gonadotropin (hCG), thyroid hormone regulation, peroxisome proliferator activated receptor protein gamma (PPARγ), leptin, transforming growth factor beta, epiregulin, growth differentiation factor 15, small nucleolar RNAs, serotonin, and vitamin D. Some of these are well-established as biomarkers of placental-fetal endocrine disruption, while others are not well studied and were selected based on discovery analyses of the placental transcriptome. A literature search on these biomarkers summarizes evidence of placenta-specific production and regulation of each biomarker, and their role in fetal reproductive tract, brain, and other specific domains of fetal development. In this review, we extend the theory of fetal programming to placental-fetal programming.

Valproic acid elevates HIF-1α-mediated CGB expression and suppresses glucose uptake in BeWo cells

Placental dysfunction can disrupt pregnancy. However, few studies have assessed the effects of chemical-induced toxicity on placental function. Here, we examined the effects of valproic acid (VPA) as a model chemical on production of hormones and on glucose uptake in human choriocarcinoma cell line BeWo. Cells were treated with forskolin to differentiate into syncytiotrophoblasts, which were then treated with VPA for 72 hr. Real-time RT-PCR analysis showed that VPA significantly increased the mRNA expression of chorionic gonadotropin β (CGB), a hormone that is produced by the placenta in the first trimester of pregnancy, relative to that in the forskolin-only group. It also suppressed the increase in intracellular glucose uptake and GLUT1 level observed in the forskolin-only group. RNA-seq analysis and pathway database analysis revealed that VPA consistently decreased the level of HIF-1α protein and expression of its downstream target genes HK2 and ADM in the hypoxia pathway. Cobalt chloride, a HIF-1α inducer, inhibited CGB upregulation in VPA-treated cells and rescued VPA-induced suppression of glucose uptake and GLUT1 level. Thus, HIF-1α-mediated elevation of CGB expression and suppression of glucose uptake by VPA is a novel mechanism of placental dysfunction.

Hyperglycosylated-hCG: Its Role in Trophoblast Invasion and Intrauterine Growth Restriction

Human chorionic gonadotropin (hCG) is produced by the placenta and its roles have been studied for over a century, being the first known pregnancy-related protein. Although its main role is to stimulate the production of progesterone by corpus luteal cells, hCG does not represent just one biologically active molecule, but a group of at least five variants, produced by different cells and each with different functions. The hyperglycosylated variant of hCG (H-hCG) plays a key role in trophoblast invasion, placental development and fetal growth. During trophoblast invasion, H-hCG promotes extravillous cytotrophoblast cells to infiltrate the decidua, and also to colonize and remodel the spiral arteries in to low resistance, larger-diameter vessels. As fetal growth is heavily reliant on nutrient availability, impaired trophoblast invasion and remodeling of the uterine arteries, leads to a defective perfusion of the placenta and fetal growth restriction. Understanding the function of H-hCG in the evolution of the placenta might unveil new ways to manage and treat fetal growth restriction.

Characterization of beta subunit variants of recombinant human chorionic gonadotrophin

Human chorionic gonadotropin (hCG), an endogenous glycoprotein hormone, has been widely used for the treatment of infertility and corpus luteum defect in women. The biological specificity of hCG is essentially determined by its beta (β-) subunit, whereas the alpha (α-) subunit is a common subunit shared among the gonadotropin family. In development of a therapeutic recombinant hCG, the purity analysis showed that the beta (β-) subunit has two variants, β1 and β2. Structural characterization using a combination of analytical techniques has demonstrated that β1-subunit is derived from non-glycosylation at Asn 13, whereas β2-subunit is a normal species with complete N-glycosylation at both Asn 13 and Asn 30. In vivo Bioactivity evaluation of the r-hCG fractions with various ratios of β1-and β2-subunits showed that incomplete glycosylation at Asn 13 potentially reduced the biological activity of r-hCG to promote uterus growth. Although hCG has a long history of medicinal use, this is the first report to identify the structural difference of hCG β-subunit variants, as well as to preliminary establish the structure-activity relationship of this variation. The obtained results also suggest the importance of variant characterization and necessary quality control of product variants during the development of recombinant protein therapeutics.

Roles of N-linked glycosylation and glycan-binding proteins in placentation: trophoblast infiltration, immunomodulation, angiogenesis, and pathophysiology

Protein N-linked glycosylation is a structurally diverse post-translational modification that stores biological information in a larger order of magnitude than other post-translational modifications such as phosphorylation, ubiquitination and acetylation. This gives N-glycosylated proteins a diverse range of properties and allows glyco-codes (glycan-related information) to be deciphered by glycan-binding proteins (GBPs). The intervillous space of the placenta is richly populated with membrane-bound and secreted glycoproteins. Evidence exists to suggest that altering the structural nature of their N-glycans can impact several trophoblast functions, which include those related to interactions with decidual cells. This review summarizes trophoblast-related activities influenced by N-glycan-GBP recognition, exploring how different subtypes of trophoblasts actively adapt to characteristics of the decidualized endometrium through cell-specific expression of N-glycosylated proteins, and how these cells receive decidua-derived signals via N-glycan-GBP interactions. We highlight work on how changes in N-glycosylation relates to the success of trophoblast infiltration, interactions of immunomodulators, and uterine angiogenesis. We also discuss studies that suggest aberrant N-glycosylation of trophoblasts may contribute to the pathogenesis of pregnancy complications (e.g. pre-eclampsia, early spontaneous miscarriages and hydatidiform mole). We propose that a more in-depth understanding of how N-glycosylation shapes trophoblast phenotype during early pregnancy has the potential to improve our approach to predicting, diagnosing and alleviating poor maternal/fetal outcomes associated with placental dysfunction.

Silver nanoparticles suppress forskolin-induced syncytialization in BeWo cells

Opportunities for the exposure of pregnant women to engineered nanoparticles have been increasing with the expanding use of these materials. Therefore, there are concerns that nanoparticles could have adverse effects on the establishment and maintenance of pregnancy. The effects of nanoparticles on the mother and fetus have been evaluated from this perspective, but there is still little knowledge about the effects on placentation and function acquisition, which are essential for the successful establishment and maintenance of pregnancy. Formation of the syncytiotrophoblast is indispensable for the acquisition of placental function, and impairment of syncytialization inevitably affects pregnancy outcomes. Here, we assessed the effect of nanoparticles on placental formation by using forskolin-treated BeWo cells, a typical in vitro model of trophoblast syncytialization. Immunofluorescence staining analysis revealed that silver nanoparticles with a diameter of 10 nm (nAg10) (at 0.156 µg/mL) significantly decreased the proportion of syncytialized BeWo cells, but gold nanoparticles with a diameter of 10 nm did not. Consistently, only nAg10 (at 0.156 µg/mL) significantly suppressed forskolin-induced elevation of CGB and SDC1 mRNA expression levels and human chorionic gonadotropin β production in a dose-dependent manner; these molecules are all markers of syncytialization. Besides, nAg10 significantly decreased the expression of ERVFRD-1, which encodes proteins associated with cell fusion. Moreover, nAg10 tended to suppress the expression of sFlt-1 e15a, a placental angiogenesis marker. Collectively, our data suggest that nAg10 could suppress formation of the syncytiotrophoblast and that induce placental dysfunction and the following poor pregnancy outcomes.

Using high throughput screens to predict miscarriages with placental stem cells and long-term stress effects with embryonic stem cells

A problem in developmental toxicology is the massive loss of life from fertilization through gastrulation, and the surprising lack of knowledge of causes of miscarriage. Half to two-thirds of embryos are lost, and environmental and genetic causes are nearly equal. Simply put, it can be inferred that this is a difficult period for normal embryos, but that environmental stresses may cause homeostatic responses that move from adaptive to maladaptive with increasing exposures. At the lower 50% estimate, miscarriage causes greater loss-of-life than all cancers combined or of all cardio- and cerebral-vascular accidents combined. Surprisingly, we do not know if miscarriage rates are increasing or decreasing. Overshadowed by the magnitude of miscarriages, are insufficient data on teratogenic or epigenetic imbalances in surviving embryos and their stem cells. Superimposed on the difficult normal trajectory for peri-gastrulation embryos are added malnutrition, hormonal, and environmental stresses. An overarching hypothesis is that high throughput screens (HTS) using cultured viable reporter embryonic and placental stem cells (e.g., embryonic stem cells [ESC] and trophoblast stem cells [TSC] that report status using fluorescent reporters in living cells) from the pre-gastrulation embryo will most rapidly test a range of hormonal, environmental, nutritional, drug, and diet supplement stresses that decrease stem cell proliferation and imbalance stemness/differentiation. A second hypothesis is that TSC respond with greater sensitivity in magnitude to stress that would cause miscarriage, but ESC are stress-resistant to irreversible stemness loss and are best used to predict long-term health defects. DevTox testing needs more ESC and TSC HTS to model environmental stresses leading to miscarriage or teratogenesis and more research on epidemiology of stress and miscarriage. This endeavor also requires a shift in emphasis on pre- and early gastrulation events during the difficult period of maximum loss by miscarriage.

Human Chorionic Gonadotropin Modulates the Transcriptome of the Myometrium and Cervix in Late Gestation

Human chorionic gonadotropin (hCG) is a critical hormone for the establishment and maintenance of pregnancy. hCG administration prevents the onset of preterm labor in mice; yet, the transcriptomic changes associated with this tocolytic effect that take place in the myometrium and cervix have not been elucidated. Herein, we implemented both discovery and targeted approaches to investigate the transcriptome of the myometrium and cervix after hCG administration. Pregnant mice were intraperitoneally injected with 10 IU of hCG on 13.0, 15.0, and 17.0 days post coitum, and the myometrium and cervix were collected. RNA sequencing was performed to determine differentially expressed genes, enriched biological processes, and impacted KEGG pathways. Multiplex qRT-PCR was performed to investigate the expression of targeted contractility- and inflammation-associated transcripts. hCG administration caused the differential expression of 720 genes in the myometrium. Among the downregulated genes, enriched biological processes were primarily associated with regulation of transcription. hCG administration downregulated key contractility genes, Gja1 and Oxtr, but upregulated the prostaglandin-related genes Ptgfr and Ptgs2 and altered the expression of inflammation-related genes in the myometrium. In the cervix, hCG administration caused differential expression of 3348 genes that were related to inflammation and host defense, among others. The downregulation of key contractility genes and upregulation of prostaglandin-related genes were also observed in the cervix. Thus, hCG exerts tocolytic and immunomodulatory effects in late gestation by altering biological processes in the myometrium and cervix, which should be taken into account when considering hCG as a potential treatment to prevent the premature onset of labor.

Unconventional Actions of Glycoprotein Hormone Subunits: A Comprehensive Review

The glycoprotein hormones (GPH) are heterodimers composed of a common α subunit and a specific β subunit. They act by activating specific leucine-rich repeat G protein-coupled receptors. However, individual subunits have been shown to elicit responses in cells devoid of the receptor for the dimeric hormones. The α subunit is involved in prolactin production from different tissues. The human chorionic gonadotropin β subunit (βhCG) plays determinant roles in placentation and in cancer development and metastasis. A truncated form of the thyrotropin (TSH) β subunit is also reported to have biological effects. The GPH α- and β subunits are derived from precursor genes (gpa and gpb, respectively), which are expressed in most invertebrate species and are still represented in vertebrates as GPH subunit paralogs (gpa2 and gpb5, respectively). No specific receptor has been found for the vertebrate GPA2 and GPB5 even if their heterodimeric form is able to activate the TSH receptor in mammals. Interestingly, GPA and GPB are phylogenetically and structurally related to cysteine-knot growth factors (CKGF) and particularly to a group of antagonists that act independently on any receptor. This review article summarizes the observed actions of individual GPH subunits and presents the current hypotheses of how these actions might be induced. New approaches are also proposed in light of the evolutionary relatedness with antagonists of the CKGF family of proteins.

Hyperglycosylated hCG activates LH/hCG-receptor with lower activity than hCG

While human chorionic gonadotropin (hCG) appears to have an essential role in early pregnancy, it is controversial whether the hyperglycosylated form of hCG (hCG-h), which is the major hCG isoform during the first 4-5 weeks of pregnancy, is able to activate LH/hCG receptor (LHCGR). To address this, we utilized different extensively characterized hCG and hCGβ reference reagents, cell culture- and urine-derived hCG-h preparations, and an in vitro reporter system for LHCGR activation. The WHO hCG reference reagent (99/688) was found to activate LHCGR with an EC₅₀-value of 3.3 ± 0.6 pmol/L (n = 9). All three studied hCG-h preparations were also able to activate LHCGR, but with a lower potency (EC₅₀-values between 7.1 ± 0.5 and 14 ± 3 pmol/L, n = 5-11, for all P < 0.05 as compared to the hCG reference). The activities of commercial urinary hCG (Pregnyl) and recombinant hCG (Ovitrelle) preparations were intermediate between those of the hCG reference and the hCG-h. These results strongly suggest that the hCG-h is functionally similar to hCG, although it has lower potency for LHCGR activation. Whether this explains the reduced proportion of hCG-h to hCG reported in patients developing early onset pre-eclampsia or those having early pregnancy loss remains to be determined.

Establishment of a three-dimensional model to study human uterine angiogenesis

STUDY QUESTION

Can primary human uterine microvascular endothelial cells (UtMVECs) be used as a model to study uterine angiogenic responses in vitro that are relevant in pregnancy?

SUMMARY ANSWER

UtMVECs demonstrated angiogenic responses when stimulated with proangiogenic factors, including sphingosine 1-phosphate (S1P), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), physiological levels of wall shear stress (WSS), human chorionic gonadotropin (hCG) and various combinations of estrogen and progesterone.

WHAT IS KNOWN ALREADY

During sprouting angiogenesis, signaling from growth factors and cytokines induces a monolayer of quiescent endothelial cells (ECs) lining the vasculature to degrade the extracellular matrix and invade the surrounding tissue to form new capillaries. During pregnancy and the female reproductive cycle, the uterine endothelium becomes activated and undergoes sprouting angiogenesis to increase the size and number of blood vessels in the endometrium.

STUDY DESIGN, SIZE, DURATION

The study was designed to examine the angiogenic potential of primary human UtMVECs using the well-characterized human umbilical vein EC (HUVEC) line as a control to compare angiogenic potential. ECs were seeded onto three-dimensional (3D) collagen matrices, supplemented with known proangiogenic stimuli relevant to pregnancy and allowed to invade for 24 h. Sprouting responses were analyzed using manual and automated methods for quantification.

PARTICIPANTS/MATERIALS, SETTING, METHODS

RT-PCR, Western blot analysis and immunostaining were used to characterize UtMVECs. Angiogenic responses were examined using 3D invasion assays. Western blotting was used to confirm signaling responses after proangiogenic lipid, pharmacological inhibitor, and recombinant lentiviral treatments. All experiments were repeated at least three times.

MAIN RESULTS AND THE ROLE OF CHANCE

After ensuring that UtMVECs expressed the proper endothelial markers, we found that UtMVECs invade 3D collagen matrices dose-dependently in response to known proangiogenic stimuli (e.g. S1P, VEGF, bFGF, hCG, estrogen, progesterone and WSS) present during early pregnancy. Invasion responses were positively correlated with phosphorylation of phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) and p42/p44 mitogen-activated protein kinase (ERK). Inhibition of these second messengers significantly impaired sprouting (P < 0.01). Gene silencing of membrane type 1-matrix metalloproteinase using multiple approaches completely abrogated sprouting (P < 0.001). Finally, UtMVECs displayed a unique ability to undergo sprouting in response to hCG, and combined estrogen and progesterone treatment.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

The study of uterine angiogenesis in vitro has limitations and any findings many not fully represent the in vivo state. However, these experiments do provide evidence for the ability of UtMVECs to be used in functional sprouting assays in a 3D environment, stimulated by physiological factors that are produced locally within the uterus during early pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

We show that UtMVECs can be used reliably to investigate how growth factors, hormones, lipids and other factors, such as flow, affect angiogenesis in the uterus.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by NIH award HL095786 to K.J.B. The authors have no conflicts of interest.

Clinical Utility of Hyperglycosylated hCG in Serum Taken before Hydatidiform Mole Evacuation to Predict Persistent Trophoblastic Disease

Objective

Human chorionic gonadotropin (hCG) is widely used in the management of hydatidiform mole and persistent trophoblastic disease (PTD). Studies on hyperglycosylated human chorionic gonadotropin (invasive trophoblast antigen, ITA) in PTD are limited. In serum samples taken before evacuation of molar pregnancies we measured the concentrations of free hCG β-subunit (free hCGβ), “total” hCG (hCG+hCGβ) and ITA, and determined whether ITA, the two other hCG analytes, or the calculated ratios of hCGβ/hCG+hCGβ, hCGβ/ITA and hCG+hCGβ/ITA could predict the later development of PTD.

Design

A retrospective study based on blood specimens collected in the Dutch Central Registry for Hydatidiform Moles. The study group comprised 97 patients with hydatidiform moles who did not develop PTD after mole evacuation and 33 patients who did develop PTD.

Methods

Serum samples from 130 patients with hydatidiform mole with or without PTD were assayed using specific (radio)immunoassays for free hCGβ, total hCG, and ITA. From these analytes we also calculated the ratios hCGβ/hCG+hCGβ, hCGβ/ITA, and hCG+hCGβ/ITA. To predict the development of PTD from these analytes and parameters we performed receiver-operating characteristic (ROC) curve analysis, resulting in areas under the curve (AUCs) that represented the diagnostic accuracy which was rated in a range from excellent (AUC >0.9 or <0.1) to poor (AUC 0.4–0.6).

Results

The diagnostic accuracy of ITA was moderate (0.618) and not different from that of free hCGβ (0.610) and hCG+hCGβ (0.622).

Conclusions

ITA as well as the other analytes and parameters in serum taken prior to evacuation from patients with molar pregnancies cannot be used to predict the subsequent development of persistent trophoblastic disease.

hCG: Biological Functions and Clinical Applications

Human chorionic gonadotropin (hCG) is produced primarily by differentiated syncytiotrophoblasts, and represents a key embryonic signal that is essential for the maintenance of pregnancy. hCG can activate various signaling cascades including mothers against decapentaplegic homolog 2 (Smad2), protein kinase C (PKC), and/or protein kinase A (PKA) in several cells types by binding to luteinizing hormone/chorionic gonadotropin receptor (LHCGR) or potentially by direct/indirect interaction with transforming growth factor beta receptor (TGFβR). The molecule displays specialized roles in promoting angiogenesis in the uterine endothelium, maintaining myometrial quiescence, as well as fostering immunomodulation at the maternal-fetal interface. It is a member of the glycoprotein hormone family that includes luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and follicle-stimulating hormone (FSH). The α-subunit of hCG displays homologies with TSH, LH, and FSH, whereas the β subunit is 80–85% homologous to LH. The hCG molecule is produced by a variety of organs, exists in various forms, exerts vital biological functions, and has various clinical roles ranging from diagnosis and monitoring of pregnancy and pregnancy-related disorders to cancer surveillance. This review presents a detailed examination of hCG and its various clinical applications.

Modulators of the Balance between M1 and M2 Macrophages during Pregnancy

Macrophages are a subset of mononuclear phagocytes of the innate immune system with high plasticity and heterogeneity. At the maternal–fetal interface, macrophages are present in all stages of pregnancy and involved in a variety of activities, including regulation of immune cell activities, decidualization, placental cell invasion, angiogenesis, parturition, and postpartum uterine involution. The activation state and function of uterine–placental macrophages are largely dependent on the local tissue microenvironment. However, disruption of the uterine microenvironment can have profound effects on macrophage activity and subsequently impact pregnancy outcome. Thus, appropriately and timely regulated macrophage polarization has been considered a key determinant of successful pregnancy. Targeting macrophage polarization might be an efficient strategy for maintaining maternal–fetal immune homeostasis and a normal pregnancy. Here, we will review the latest findings regarding the modulators regulating macrophage polarization in healthy pregnancies and pregnancy complications, which might provide a basis for macrophage-centered therapeutic strategies.

First trimester serum placental growth factor and hyperglycosylated human chorionic gonadotropin are associated with pre-eclampsia: a case control study

Background

To study whether maternal serum hyperglycosylated human chorionic gonadotropin (hCG-h) improves first trimester prediction of pre-eclampsia when combined with placental growth factor (PlGF), pregnancy-associated plasma protein-A (PAPP-A) and maternal risk factors.

Methods

Gestational-age-adjusted concentrations of hCG, hCG-h, PlGF and PAPP-A were analysed in serum samples by time-resolved immunofluorometric assays at 8–13 weeks of gestation. The case–control study included 98 women who developed pre-eclampsia, 25 who developed gestational hypertension, 41 normotensive women with small-for-gestational-age (SGA) infants and 177 controls.

Results

Of 98 women with pre-eclampsia, 24 women developed preterm pre-eclampsia (diagnosis < 37 weeks of gestation) and 13 of them had early-onset pre-eclampsia (diagnosis < 34 weeks of gestation). They had lower concentrations of PlGF, PAPP-A and proportion of hCG-h to hCG (%hCG-h) than controls. In receiver-operating characteristics (ROC) curve analysis, the area under the curve (AUC) for the combination of PlGF, PAPP-A, %hCG-h, nulliparity and mean arterial blood pressure was 0.805 (95% confidence interval, CI, 0.699–0.912) for preterm pre-eclampsia and 0.870 (95% CI 0.750–0.988) for early-onset pre-eclampsia. Without %hCG-h the AUC values were 0.756 (95% CI 0.651–0.861) and 0.810 (95% CI 0.682–0.938) respectively. For prediction of gestational hypertension, the AUC for %hCG-h was 0.708 (95% CI 0.608–0.808), but for other markers the AUC values were not significant. None of the AUC values were significant for the prediction of SGA infants in normotensive women.

Conclusions

First trimester maternal serum %hCG-h tended to improve prediction of preterm and early-onset pre-eclampsia when combined with PlGF, PAPP-A and maternal risk factors.

Human Chorionic Gonadotropin Has Anti-Inflammatory Effects at the Maternal-Fetal Interface and Prevents Endotoxin-Induced Preterm Birth, but Causes Dystocia and Fetal Compromise in Mice

Human chorionic gonadotropin (hCG) is implicated in the maintenance of uterine quiescence by down-regulating myometrial gap junctions during pregnancy, and it was considered as a strategy to prevent preterm birth after the occurrence of preterm labor. However, the effect of hCG on innate and adaptive immune cells implicated in parturition is poorly understood. Herein, we investigated the immune effects of hCG at the maternal-fetal interface during late gestation, and whether this hormone can safely prevent endotoxin-induced preterm birth. Using immunophenotyping, we demonstrated that hCG has immune effects at the maternal-fetal interface (decidual tissues) by: 1) increasing the proportion of regulatory T cells; 2) reducing the proportion of macrophages and neutrophils; 3) inducing an M1 → M2 macrophage polarization; and 4) increasing the proportion of T helper 17 cells. Next, ELISAs were used to determine whether the local immune changes were associated with systemic concentrations of progesterone, estradiol, and/or cytokines (IFNgamma, IL1beta, IL2, IL4, IL5, IL6, IL10, IL12p70, KC/GRO, and TNFalpha). Plasma concentrations of IL1beta, but not progesterone, estradiol, or any other cytokine, were increased following hCG administration. Pretreatment with hCG prevented endotoxin-induced preterm birth by 44%, proving the effectiveness of this hormone as an anti-inflammatory agent. However, hCG administration alone caused dystocia and fetal compromise, as proven by Doppler ultrasound. These results provide insight into the mechanisms whereby hCG induces an anti-inflammatory microenvironment at the maternal-fetal interface during late gestation, and demonstrate its effectiveness in preventing preterm labor/birth. However, the deleterious effects of this hormone on mothers and fetuses warrant caution.

Adverse effects of 4-tert-octylphenol on the production of oxytocin and hCG in pregnant rats

Endocrine-disrupting chemicals (EDCs) are exogenous substances that alter the structure or function of the endocrine system. 4-Tert-octylphenol (OP) is one of the most representative EDCs and has estrogenic effects. In this study, we examined the effects of ethinyl estradiol (EE) and OP on the pituitary gland, placenta, and uterus of pregnant rats. Expression levels of human chorionic gonadotropin (hCG), oxytocin (OT), and contraction-associated proteins (CAPs) were determined, and uterine contractile activity was measured by uterine contraction assay. EE and OP both increased mRNA expression of OT and hCG in the pituitary gland but not the placenta. Since OT and hCG control uterine contraction, we next examined CAP expression in the uterus. Expression of 15-hydroxyprostaglandin-dehydrogenase (PGDH) was upregulated by OP, whereas expression of other CAPs was unaffected. To clarify the effect of OP on uterine contraction in pregnant rats, uterine contraction assay was performed. The 17β-Estradiol (E2) did not affect contraction of primary uterine cells harvested from pregnant rats in a 3D collagen gel model. However, OP showed different effects from E2 by significantly reducing contraction activity. In summary, we demonstrated that OP interferes with regulation of OT and hCG in the pituitary gland as well as PGDH in the uterus, thereby reducing uterine contraction activity. This result differs from the action of endogenous E2. Collectively, these findings suggest that exposure to EDCs such as OP during pregnancycan reduce uterine contractile ability, which may result in contraction-associated adverse effects such as metratonia, bradytocia, and uterine leiomyomata.

Concentrations of human chorionic gonadotrophin in very early pregnancy and subsequent pre-eclampsia: a cohort study

STUDY QUESTION

Are low serum concentrations of human chorionic gonadotrophin (hCG) in very early pregnancy associated with pre-eclampsia risk?

SUMMARY ANSWER

Low hCG concentrations in very early pregnancy are associated with increased risk of severe pre-eclampsia.

WHAT IS KNOWN ALREADY

Low maternal serum concentrations of hCG early in pregnancy may indicate impaired proliferation or invasion of trophoblast cells, and thus low hCG concentrations may serve as a marker for impaired placental development. Impaired placental development is assumed to be a cause of pre-eclampsia, but there is little prospective evidence to support this hypothesis.

STUDY DESIGN, SIZE, DURATION

We performed a prospective cohort study of pregnancies after IVF at Oslo University Hospital 1996-2010 with linkage to the Medical Birth Registry of Norway to obtain information on pre-eclampsia development.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We included 2405 consecutive singleton pregnancies and examined the association of maternal serum hCG concentrations (measured using Elecsys, Roche) on Day 12 after embryo transfer with the risk of any pre-eclampsia and of mild and severe pre-eclampsia.

MAIN RESULTS AND THE ROLE OF CHANCE

HCG concentrations were inversely associated with pre-eclampsia risk in a dose-dependent manner (Ptrend 0.02). Compared with women with hCG ≥150 IU/l, women with hCG <50 IU/l were at 2-fold higher overall risk of pre-eclampsia [absolute risk 6.4 versus 2.8%; odds ratio (OR) 2.3, 95% confidence interval (CI) 1.2-4.7]. The inverse association was restricted to severe pre-eclampsia (Ptrend 0.01), thus, women with hCG <50 IU/l were at 4-fold higher risk of severe pre-eclampsia than women with hCG ≥150 IU/l (absolute risk 3.6 versus 0.9%; OR 4.2, 95% CI 1.4-12.2). For mild pre-eclampsia, there was no corresponding association (Ptrend 0.36).

LIMITATIONS, REASONS FOR CAUTION

Results for IVF pregnancies may not be generalizable to spontaneously conceived pregnancies.

WIDER IMPLICATIONS OF THE FINDINGS

Plausible causes of low maternal hCG concentrations very early in pregnancy include impaired placental development and delayed implantation. Thus, these results provide prospective evidence to support the hypothesis that impaired placental development may be associated with subsequent development of severe pre-eclampsia.

STUDY FUNDING/COMPETING INTEREST

The study was financially supported by the Research Council of Norway. None of the authors has any conflict of interest to declare.

Hyperglycosylated human chorionic gonadotropin as an early predictor of pregnancy outcomes after in vitro fertilization

OBJECTIVE

To determine whether serum hyperglycosylated human chorionic gonadotropin (hhCG) measured as early as 9 days after egg retrieval can predict ongoing pregnancies after in vitro fertilization and fresh embryo transfer (IVF-ET).

DESIGN

Cohort

SETTING

Academic assisted reproduction center.

PATIENT(S)

Consecutive patients undergoing IVF-ET INTERVENTION(S): Serum hhCG and hCG levels measured 9 (D9) and 16 (D16) days after egg retrieval

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy beyond 9 weeks of gestation.

RESULT(S)

Ongoing pregnancy (62 of 112 participants) was associated with higher D9 levels of hhCG and hCG. However, hhCG was detectable in all D9 OP samples, while hCG was detectable in only 22%. A D9 hhCG level of >110 pg/mL was 96% specific for an ongoing pregnancy, yielding a positive predictive value of 94%. Compared with the D9 hCG levels, hhCG was more sensitive and had a larger area under the curve (0.87 vs. 0.67, respectively). The diagnostic test characteristics were similar between the D16 hhCG and hCG levels.

CONCLUSION(S)

In patients undergoing assisted reproduction, a test to detect pregnancy early and predict outcomes is highly desirable, and hhCG is detectable in serum 9 days after egg retrieval IVF-ET cycles. In this early assessment, hhCG was superior to traditional hCG and highly predictive of ongoing pregnancies.

First trimester hyperglycosylated human chorionic gonadotrophin in serum - a marker of early-onset preeclampsia

INTRODUCTION

Recent studies indicate that treatment with low-dose aspirin may reduce the risk of preeclampsia. Thus, early prediction of preeclampsia is needed. Low serum concentrations of hyperglycosylated human chorionic gonadotrophin (hCG-h) are associated with early pregnancy loss. We therefore studied whether it may serve as an early marker of preeclampsia.

METHODS

A nested case-control study included 158 women with subsequent preeclampsia, 41 with gestational hypertension, 81 normotensive women giving birth to small-for-gestational-age (SGA) infants and 427 controls participating in first trimester screening for Down's syndrome between 8 and 13 weeks of gestation. Gestational-age-adjusted multiples of medians (MoMs) were calculated for serum concentrations of hCG-h, the free beta subunit of hCG (hCGβ) and pregnancy-associated plasma placental protein A (PAPP-A) and the proportion of hCG-h to hCG (%hCG-h). Clinical risk factors including mean arterial pressure (MAP) and parity were also included in the risk calculation.

RESULTS

In women with subsequent preeclampsia %hCG-h was lower than in controls (median MoM 0.92, P < 0.001), especially in 29 cases with early-onset preeclampsia (0.86, P < 0.001), in which PAPP-A also was reduced (0.95, P = 0.001). At 90% specificity for prediction of early-onset preeclampsia, sensitivity was 56% (95% confidence interval, 52-61%) for %hCG-h, 33% (28-37%) for PAPP-A, and 69% (51-83%) for the combination of these with first trimester MAP and parity. The area under the receiver-operating characteristic (ROC) curve for the combination of all these was 0.863 (0.791-0.935).

CONCLUSIONS

hCG-h is a promising first trimester marker for early-onset preeclampsia. Addition of PAPP-A and maternal risk factors may improve the results.

Human chorionic gonadotropin and its free β-subunit stimulate trophoblast invasion independent of LH/hCG receptor

Both paracrine and autocrine factors are involved in the regulation of trophoblast invasion. One of these factors is human chorionic gonadotropin (hCG), which stimulates trophoblast invasion. The stimulatory activity has especially been ascribed to a hyperglycosylated form of hCG (hCG-h) that is expressed in early pregnancy. We compared the stimulatory activities of different forms of hCG and its free β-subunit (hCGβ) on trophoblast invasion. hCG, hCG-h, hCGβ, and its hyperglycosylated form (hCGβ-h) stimulated the invasion of JEG-3 choriocarcinoma cells. The stimulatory effect of hCGβ was also confirmed with primary human trophoblasts. Down-regulation of the LH/hCG receptor by RNA-interference did not significantly reduce the effect of hCGβ and hCG on cell invasion. Increased invasion was associated with increased levels of MMP-2, MMP-9 and activity of uPA. Our findings suggest that hCG, hCGβ and their hyperglycosylated forms stimulate the invasion of trophoblast cells independent of the classical LH/hCG-receptor.

IVF culture medium affects human intrauterine growth as early as the second trimester of pregnancy

STUDY QUESTION

When does a difference in human intrauterine growth of singletons conceived after IVF and embryo culture in two different culture media appear?

SUMMARY ANSWER

Differences in fetal development after culture of embryos in one of two IVF media were apparent as early as the second trimester of pregnancy.

WHAT IS KNOWN ALREADY

Abnormal fetal growth patterns are a major risk factor for the development of chronic diseases in adult life. Previously, we have shown that the medium used for culturing embryos during the first few days after fertilization significantly affects the birthweight of the resulting human singletons. The exact onset of this growth difference was unknown.

STUDY DESIGN, SIZE AND DURATION

In this retrospective cohort study, all 294 singleton live births after fresh embryo transfer in the period July 2003 to December 2006 were included. These embryos originated from IVF treatments that were part of a previously described clinical trial. Embryos were allocated to culture in either Vitrolife or Cook commercially available sequential culture media.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We analysed ultrasound examinations at 8 (n = 290), 12 (n = 83) and 20 weeks' (n = 206) gestation and used first-trimester serum markers [pregnancy-associated plasma protein-A (PAPP-A) and free β-hCG]. Differences between study groups were tested by the Student's t-test, χ(2) test or Fisher's exact test, and linear multivariable regression analysis to adjust for possible confounders (for example, parity, gestational age at the time of ultrasound and fetal gender).

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 294 singleton pregnancies (Vitrolife group nVL = 168, Cook group: nC = 126) from 294 couples were included. At 8 weeks' gestation, there was no difference between crown-rump length-based and ovum retrieval-based gestational age (ΔGA) (nVL = 163, nC = 122, adjusted mean difference, -0.04 days, P = 0.84). A total of 83 women underwent first-trimester screening at 12 weeks' gestation (nVL = 45, nC = 38). ΔGA, nuchal translucency (multiples of median, MoM) and PAPP-A (MoM) did not differ between the study groups. Free β-hCG (MoM) ± SEM differed significantly (1.55 ± 0.19 in Vitrolife versus 1.06 ± 0.10 in Cook; P = 0.031, Student's t-test). At 20 weeks' gestation, a more advanced GA, reflecting an increased fetal growth, was seen at ultrasound examination in the Vitrolife group (n = 115) when compared with the Cook group (n = 91). After adjustment for confounding factors, both the difference between GA based on three biparietal diameter dating formulas minus the actual (ovum retrieval based) GA (adjusted mean difference + 1.14 days (P = 0.04), +1.14 days (P = 0.04) and +1.36 days (P = 0.048)), as well as head circumference (HC) and trans-cerebellar diameter (TCD) were significantly higher in the Vitrolife group (HCvl 177.3 mm, HCc 175.9 mm, adjusted mean difference 1.8, P = 0.03; TCDvl 20.5 mm, TCDc 20.2 mm, adjusted mean difference 0.4, P = 0.008).

LIMITATIONS, REASONS FOR CAUTION

A first trimester (12 weeks) fetal screening was not yet offered routinely during the study period, therefore only 28% of women in our study participated in this elective screening programme. Although all sonographers were experienced and specially trained to perform these ultrasound examinations and were unaware of the randomization procedure, we cannot totally rule out possible intra- and inter-observer variability. Despite being indispensable in daily practice, sonographic weight formulas have a limited accuracy.

WIDER IMPLICATIONS OF THE FINDINGS

According to the fetal origins hypothesis, many adult diseases originate in utero owing to adaptations made by the fetus to the environment it encounters. This study indicates that the embryonic environment is already important for fetal development. Therefore, our study emphasizes the need to investigate fetal growth patterns after assisted reproduction technologies and long-term health outcomes of IVF children, especially in relation to the culture medium used during the first few days of preimplantation development.

TRIAL REGISTRATION NUMBER

Not applicable.

Human chorionic gonadotropin (hCG) in the secretome of cultured embryos: hyperglycosylated hCG and hCG-free beta subunit are potential markers for infertility management and treatment

Human chorionic gonadotropin (hCG) is produced by trophoblast cells throughout pregnancy, and gene expression studies have indicated that hCG-beta subunit (hCGβ) expression is active at the 2 blastomere stage. Here, we investigated the qualitative hCG output of developing embryos in culture and hCG isoforms expressed in the secretome as a novel sensitive method for detecting hCG. Culture media was collected from the culture plates of 118 embryos in culture (including controls and embryos at different stages of culture) from 16 patients undergoing routine fertility treatment. The hCGβ was detectable in media from 2 pronuclear (2PN) stage embryos through to the blastocyst stage. The hCGβ was absent in 1PN and arrested embryos as well as all media controls. Prior to hatching, hyperglycosylated hCG (hCGh) was observed selectively in 3PN embryos, but after hatching, along with hCG, became the dominant hCG molecule observed. We have reported at the 2PN stage the earliest evidence of hCGβ expression in embryos. There is a suggestion this may be indicative of quality in early embryos, and hCGh seen at the pronuclear stage may suggest triploid abnormality. The dominance of hCG, and hCGh expression, seen after blastocyst hatching may be indicative of potential implantation success. Thus, hCG isoforms have potential roles as biomarkers of embryo viability for embryo/blastocyst transfer.

hCG in ectopic pregnancy

Ectopic pregnancies remain an important cause of morbidity and mortality in women of reproductive age. Management of these pregnancies has changed dramatically over the years. Human chorionic gonadotropin (hCG) is a glycoprotein hormone composed of 2 dissimilar subunits, alpha and beta, joined non-covalently. The free beta-subunit is the principal immuno-reactive agent in pregnancy serum samples. Improved diagnostic methods using hCG levels in combination with transvaginal ultrasound have lead to earlier detection rates, subsequent treatment and a reduction in mortality resulting from ectopic pregnancies. This chapter will describe current trends in ectopic pregnancy diagnosis based on hCG levels.

Hyperglycosylated Human Chorionic Gonadotropin in Serum of Testicular Cancer Patients

BACKGROUND

Hyperglycosylated human chorionic gonadotropin (hCG-h) contains larger and more complex carbohydrate chains than regular human chorionic gonadotropin (hCG). hCG-h is thought to be the major form of hCG produced by testicular cancers and it has been suggested to play a key role in tumor invasion, but studies on hCG-h in testicular cancer are limited. We studied whether serum hCG is hyperglycosylated, and whether measurement of hCG-h in serum offers clinical value in the management of testicular cancer.

METHODS

We determined the serum concentrations of hCG-h, hCG, and the free β subunit of hCG (hCGβ) by time-resolved immunofluorometric assays in 176 serum samples (preoperative n = 67, relapse n = 20, follow-up n = 89) obtained from 84 testicular cancer patients. We analyzed the association between preoperative serum concentrations of hCG, hCG-h, and hCGβ with known prognostic factors and progression-free survival time.

RESULTS

A major proportion of hCG was hyperglycosylated preoperatively, at relapse, and shortly after treatment. The serum concentrations of hCG-h and hCG correlated strongly with each other and had similar diagnostic value. The preoperative serum concentration of hCG-h correlated with prognostic factors and outcome in the same way as hCG. Increased preoperative hCGβ concentration predicted shorter progression-free survival.

CONCLUSIONS

Most of the hCG expressed by testicular cancers is hyperglycosylated and therefore it is important that hCG assays used for management of testicular cancer recognize hCG-h.

hCG, the wonder of today's science

BACKGROUND

hCG is a wonder. Firstly, because hCG is such an extreme molecule. hCG is the most acidic glycoprotein containing the highest proportion of sugars. Secondly, hCG exists in 5 common forms. Finally, it has so many functions ranging from control of human pregnancy to human cancer. This review examines these molecules in detail.

CONTENT

These 5 molecules, hCG, sulfated hCG, hyperglycosylated hCG, hCG free beta and hyperglycosylated free beta are produced by placental syncytiotrophoblast cells and pituitary gonadotrope cells (group 1), and by placental cytotrophoblast cells and human malignancies (group 2). Group 1 molecules are both hormones that act on the hCG/LH receptor. These molecules are central to human menstrual cycle and human pregnancy. Group 2 molecules are autocrines, that act by antagonizing a TGF beta receptor. These molecules are critical to all advanced malignancies.

CONCLUSIONS

The hCG groups are molecules critical to both the molecules of pregnancy or human life, and to the advancement of cancer, or human death.

Hyperglycosylated hCG and pregnancy failures

Considerable evidence indicates that one third of early pregnancy failures, spontaneous abortions and biochemical pregnancies, are due to chromosomal abnormalities, and two thirds are due to inappropriate implantation. These findings led us to investigate the role of hyperglycosylated hCG, an important pregnancy implantation signal, in pregnancy failures. We used urinary hCG determinations to evaluate a total of 127 pregnancies on the day of implantation, as marked by a positive urinary hCG. These included 81 normal term pregnancies, 18 spontaneous abortion pregnancies, and 28 biochemical pregnancies. Of the normal term pregnancies, the mean±standard deviation concentration of hyperglycosylated hCG was 5.4±4.3 mIU/ml equivalents, and the percentage of hyperglycosylated hCG was 88±17%. All term pregnancies produced hyperglycosylated hCG>51%. Of the 18 cases that spontaneously aborted, both the mean hyperglycosylated hCG (1.9±2.0 mIU/ml equivalents) and the percentage of hyperglycosylated hCG (41±33%) were significantly lower than in the normal pregnancy group. Only 4/18 spontaneously aborting pregnancies produced more than 51% hyperglycosylated hCG on the day of implantation. Similarly, of the 28 biochemical pregnancies, both the mean hyperglycosylated hCG (0.63±1.3 mIU/ml equivalents) and the percentage of hyperglycosylated hCG (21±29%) were significantly lower than in the normal pregnancy group. Only 4/28 pregnancies produced more than 51% hyperglycosylated hCG. Low hyperglycosylated hCG concentrations are associated with pregnancy failure. Whether this association is a primary cause of pregnancy failure or is simply a marker for an abnormal conceptus requires further investigation.

hCG, five independent molecules

INTRODUCTION

The hCG amino acid sequence supports 5 glycoproteins. All are called hCG forms. This review examines all 5 molecules, the hormone as produced by the placental syncytiotrophoblast cells, the sulfated hormone produced by the pituitary gonadotrope cells, the hyperglycosylated hCG autocrine made by placental cytotrophoblast cells, and the autocrine cancer promoters hyperglycosylated hCG, hCGß and hyperglycosylated hCGß as made by all malignancies. This review examines all the molecules and multiple proven functions, ranging from evolution to cancer promotion to hormone action.

RESULTS AND DISCUSSION

hCG forms are critical super-growth factors in humans, with an exceptional wide range of functions.

Individual deviations in human chorionic gonadotropin concentrations during pregnancy

BACKGROUND

Serum and urine human chorionic gonadotropin (hCG) vary greatly during the course of pregnancy. We investigated the cause of this variation.

STUDY DESIGN

Eighty-two women provided daily urine samples during the first 6 weeks of gestation. First-void urine samples were monitored for luteinizing hormone (LH) and hCG.

RESULTS

Variation was wide when pregnancy hCG anchoring to the last menstrual period (variation 677 ± 786-fold) or to LH peak (variation 810 ± 936-fold). When pregnancy was anchored to the day of implantation (variation 187 ± 123-fold) variation was significantly reduced (P < .00005). Individual differences in the rate of hCG production were examined. hCG production ranged from 1.52-fold to 2.92-fold per day. Rate differences in hCG were also a major source of hCG variation.

CONCLUSION

Two factors are responsible for the wide fluctuation in hCG concentrations, first dating pregnancies to the start of the last menstrual period rather than the timing of implantation and second, individual pregnancy differences in the rate of hCG production.

Cell specific patterns of methylation in the human placenta

Epigenetic processes, such as DNA methylation, are known to regulate tissue specific gene expression. We explored this concept in the placenta to define whether DNA methylation is cell-type specific. Cytotrophoblasts and fibroblasts were isolated from normal midtrimester placentas. Using immunocytochemistry, we demonstrated 95% purity for cytotrophoblasts and 60-70% for fibroblasts. We compared DNA methylation profiles from cytotrophoblasts, fibroblasts and whole placental villi using bisulfite modified genomic DNA hybridized to the Illumina Methylation27 array. Euclidean cluster analysis of the DNA methylation profiles showed 2 main clusters, one containing cytotrophoblasts and placenta, the other fibroblasts. Differential methylation analysis identified 442 autosomal CpG sites that differed between cytotrophoblasts and fibroblasts, 315 between placenta and fibroblasts and 61 between placenta and cytotrophoblasts. Three candidate methylation differences were validated by targeted pyrosequencing assays. Pyrosequencing assays were developed for CpG sites less methylated in cytotrophoblasts than fibroblasts mapping to the promoter region of the beta subunit of human chorionic gonadotropin 5 (CGB5), as well as 2 CpG sites mapping to each of 2 tumor suppressor genes. Our data suggest that epigenetic regulation of gene expression is likely to be a key factor in the functional specificity of cytotrophoblasts. These data are proof of principle for cell-type specific epigenetic regulation in placenta and demonstrate that the methylation profile of placenta is mainly driven by cytotrophoblasts.

Recurrent miscarriage and hCG supplementation: a review and metaanalysis

Human chorionic gonadotropin (hCG) has been used to prevent subsequent miscarriages after previous recurrent miscarriages. In addition to the luteotrophic effects, hCG has uterine immune and autocrine actions. hCG also affects cytokine expression. A Cochrane database systematic review has indicated that hCG seems to prevent further miscarriages, (OR for miscarriage = 0.26, 95% CI 0.14-0.52). However, the trials in the Cochrane database were not matched for the number of miscarriages, 1°, 2° or 3° aborter status, maternal age, etc. and no account was made for chromosomally abnormal pregnancies. All of these impact on the subsequent prognosis and may confound the results. The previous trials in the literature all assessed urinary (u-hCG) rather than recombinant hCG (r-hCG), raising the question whether the effect on pregnancy outcome is due to hCG itself, or other urinary proteins present in u-hCG. A new trial is indicated in which r-hCG is compared to u-hCG and the most effective compared to placebo. Treatment and placebos arms should be stratified for the prognostic factors above and the results corrected for fetal chromosomal aberrations. Until such a trial is carried out, the use of hCG supplementation is empiric.

Biological functions of hCG and hCG-related molecules

BACKGROUND

hCG is a term referring to 4 independent molecules, each produced by separate cells and each having completely separate functions. These are hCG produced by villous syncytiotrophoblast cells, hyperglycosylated hCG produced by cytotrophoblast cells, free beta-subunit made by multiple primary non-trophoblastic malignancies, and pituitary hCG made by the gonadotrope cells of the anterior pituitary.

RESULTS AND DISCUSSION

hCG has numerous functions. hCG promotes progesterone production by corpus luteal cells; promotes angiogenesis in uterine vasculature; promoted the fusion of cytotrophoblast cell and differentiation to make syncytiotrophoblast cells; causes the blockage of any immune or macrophage action by mother on foreign invading placental cells; causes uterine growth parallel to fetal growth; suppresses any myometrial contractions during the course of pregnancy; causes growth and differentiation of the umbilical cord; signals the endometrium about forthcoming implantation; acts on receptor in mother's brain causing hyperemesis gravidarum, and seemingly promotes growth of fetal organs during pregnancy. Hyperglycosylated hCG functions to promote growth of cytotrophoblast cells and invasion by these cells, as occurs in implantation of pregnancy, and growth and invasion by choriocarcinoma cells. hCG free beta-subunit is produced by numerous non-trophoblastic malignancies of different primaries. The detection of free beta-subunit in these malignancies is generally considered a sign of poor prognosis. The free beta-subunit blocks apoptosis in cancer cells and promotes the growth and malignancy of the cancer. Pituitary hCG is a sulfated variant of hCG produced at low levels during the menstrual cycle. Pituitary hCG seems to mimic luteinizing hormone actions during the menstrual cycle.

Down syndrome screening: imagining the screening test of the future

Prenatal screening for Down syndrome (DS) is performed by risk calculation based on biochemical and biometric parameters. This way, approximately 75-85% of all DS cases can be detected. A way to improve detection rates is to search for new screening markers. Since the majority of biomarkers used in current DS screening are predominantly produced by the placenta, and the presence of an extra chromosome (as in DS) complicates placental development and function, it is plausible to assume that new potential screening markers may also originate from the placenta. Any alterations in these markers can be attributed to abnormal placental development and function. This article focuses on normal early placental development and function compared with that in DS pregnancies. Using this knowledge, we reason towards candidate biomarkers that may be useful in screening for DS.

USA hCG reference service, 10-year report

INTRODUCTION

The USA hCG Reference Service has been dealing with cases of persistent low levels of hCG and gestational trophoblastic diseases for 10years. Here we present the complete experience.

METHODS

Total hCG in serum and urine was measured using the Siemen's Immulite 1000 assay. Hyperglycosylated hCG, nicked hCG, free ss-subunit and ss-core fragment were measured using microtiterplate assays with antibodies B152, B151, FBT11 and B210, respectively.

RESULTS

The USA hCG Reference Service has identified 83 cases of false-positive hCG, 71 cases of aggressive gestational trophoblastic disease (GTD), 52 cases of minimally invasive GTD, 168 cases of quiescent GTD and 22 cases of placenta site trophoblastic tumor (PSTT). In addition, 103 cases of pituitary hCG have been identified, 60 cases of nontrophoblastic tumor, 4 cases of inherited hCG and 2 cases of Munchausen's syndrome. This is 565 cases total. Multiple new methods are described and tested for diagnosing all of these disorders.

CONCLUSIONS

The USA hCG Reference Service experience shows new methods for detecting multiple hCG-related disorders and recommends new approaches for detecting these hCG-related disorders.

hCG and hyperglycosylated hCG in the establishment and evolution of hemochorial placentation

The evolution of regular chorionic gonadotropin (CG) and hyperglycosylated CG are linked with the evolution of hemochorial placentation in primates. Recent research with humans shows that regular CG promotes spiral artery angiogenesis and hyperglycosylated CG controls invasion by implanting trophoblast cells. It is inferred that the evolution of regular CG and hyperglycosylated CG in early simian primates, the first species to produce these CG forms, established hemochorial placentation in this species. The circulating half-lives, and thus the circulating concentrations, of regular CG and hyperglycosylated CG increased in advanced simian primates and increased further in humans, seemingly causing greater myometrial invasion and superior angiogenesis in hemochorial placentation in advanced primates and humans. Advanced hemochorial placentation is associated with relatively high proportions of pregnancy failures in humans. This can be explained by considering human implantation inadequate in terms of invasion requirements. The demanding implantation required by the human embryo is seemingly dependent on adequate production of hyperglycosylated CG. Failures in hemochorial placentation invasion lead to anoxia and cause preeclampsia and eclampsia uniquely in humans, which can also be attributed to inadequate hyperglycosylated CG signaling. We propose here that inadequate regular CG and hyperglycosylated CG molecules are the evolutionary causes of these obstetric complications in humans.

Human chorionic gonadotropin and associated molecules

When considering human chorionic gonadotropin (hCG) and hCG tests, it is important to realize that it is not a single biological molecule. The regular form of hCG produced by differentiated syncytotrophoblast cells (regular hCG) is a hormone made with the primary function of maintaining the myometrial and decidual spiral arteries and the vascular supply of the placenta during the full course of pregnancy. Hyperglycosylated hCG (hCG with double-size O-linked oligosaccharides) is made by undifferentiated cytotrophoblast cells. This is an autocrine hormone with separate functions, it maintains invasion as in implantation of pregnancy and malignancy in gestational trophoblastic diseases. A hyperglycosylated free beta-subunit is produced by a high proportion of all malignancies. This functions as an autocrine hormone to promote the growth and invasion of the malignancy. It is important to realize when ordering an hCG test what you are measuring and whether the test ordered will detect appropriately these three variant of hCG as well as their degradation products. Most automated commercial laboratory tests, point-of-care test and over-the-counter tests are limited in what is detected, focusing only on regular hCG. This is in part due to the US FDA, who only consider hCG as a pregnancy test, and to whom only detection of regular hCG is critical. This may be a cause of test errors since primarily hyperglycosylated hCG is produced in early pregnancy, choriocarcinoma and germ cell testicular malignancies, and only free beta-subunit may be produced in other germ cell malignancies (all applications for hCG test). The exceptions are the older style hCGbeta radioimmunoassay and the Siemen's Immulite platform hCG test which detect all variant and their degradation product appropriately. Regardless of test specificity limitations, assays for hCG variants are widely used clinically in pregnancy detection, early pregnancy detection, prediction of spontaneously aborting and ectopic pregnancies and prediction of trisomy pregnancies. hCG tests are essential in managing gestational trophoblastic diseases, whether hydatidiform mole, invasive mole or choriocarcinoma, and are very useful in management of testicular malignancies and other germ cell malignancies.

New discoveries on the biology and detection of human chorionic gonadotropin

Human chorionic gonadotropin (hCG) is a glycoprotein hormone comprising 2 subunits, alpha and beta joined non covalently. While similar in structure to luteinizing hormone (LH), hCG exists in multiple hormonal and non-endocrine agents, rather than as a single molecule like LH and the other glycoprotein hormones. These are regular hCG, hyperglycosylated hCG and the free beta-subunit of hyperglycosylated hCG. For 88 years regular hCG has been known as a promoter of corpus luteal progesterone production, even though this function only explains 3 weeks of a full gestations production of regular hCG. Research in recent years has explained the full gestational production by demonstration of critical functions in trophoblast differentiation and in fetal nutrition through myometrial spiral artery angiogenesis. While regular hCG is made by fused villous syncytiotrophoblast cells, extravillous invasive cytotrophoblast cells make the variant hyperglycosylated hCG. This variant is an autocrine factor, acting on extravillous invasive cytotrophoblast cells to initiate and control invasion as occurs at implantation of pregnancy and the establishment of hemochorial placentation, and malignancy as occurs in invasive hydatidiform mole and choriocarcinoma. Hyperglycosylated hCG inhibits apoptosis in extravillous invasive cytotrophoblast cells promoting cell invasion, growth and malignancy. Other non-trophoblastic malignancies retro-differentiate and produce a hyperglycosylated free beta-subunit of hCG (hCG free beta). This has been shown to be an autocrine factor antagonizing apoptosis furthering cancer cell growth and malignancy. New applications have been demonstrated for total hCG measurements and detection of the 3 hCG variants in pregnancy detection, monitoring pregnancy outcome, determining risk for Down syndrome fetus, predicting preeclampsia, detecting pituitary hCG, detecting and managing gestational trophoblastic diseases, diagnosing quiescent gestational trophoblastic disease, diagnosing placental site trophoblastic tumor, managing testicular germ cell malignancies, and monitoring other human malignancies. There are very few molecules with such wide and varying functions as regular hCG and its variants, and very few tests with such a wide spectrum of clinical applications as total hCG.

Human chorionic gonadotropin produced by the invasive trophoblast but not the villous trophoblast promotes cell invasion and is down-regulated by peroxisome proliferator-activated receptor-gamma

A critical step in the establishment of human pregnancy is the invasion of the uterus wall by extravillous cytotrophoblasts (EVCTs) during the first trimester. It is well established that human chorionic gonadotropin hormone (hCG) is secreted by the endocrine syncytiotrophoblast (ST) into the maternal compartment. We recently reported that invasive EVCTs also produce hCG, suggesting an autocrine role in the modulation of trophoblast invasion. Here we analyzed the role of hCG secreted in vitro by primary cultures of invasive EVCT and noninvasive ST. We first demonstrated that LH/CG receptor was present in EVCTs in situ and in vitro as well as in an EVCT cell line (HIPEC65). We next showed that hCG secreted by EVCTs stimulated progesterone secretion by MA10 cells in a concentration-dependent manner. Incubation of HIPEC65 with EVCT supernatants induced a 10-fold increase in cell invasion, whereas ST supernatants had no effect. This stimulating effect was strongly decreased when hCG was depleted from EVCT supernatants containing a large amount of the hyperglycosylated form of hCG, which is almost undetectable in ST supernatants. Finally, we investigated the regulation of hCG expression by peroxisome proliferator-activated receptor (PPAR)-gamma, a nuclear receptor shown to inhibit trophoblast invasion. Activation of PPARgamma decreased alpha- and beta-subunit transcript levels and total hCG secretion in primary EVCTs. Our results offer the first evidence that hCG secreted by the invasive trophoblast, likely the hyperglycosylated form of hCG, but not by the syncytiotrophoblast, promotes trophoblast invasion and may be a PPARgamma target gene in trophoblast invasion process.

Hyperglycosylated human chorionic gonadotropin and the source of pregnancy failures

OBJECTIVE

To investigate the proportion of hyperglycosylated human chorionic gonadotropin (hCG-H) produced at the time of implantation as a predictor of pregnancy success.

DESIGN

Measuring daily urine hCG and hCG-H on the day of implantation. The time of implantation was assumed to be the first day of hCG detection (total hCG >1 mIU/mL).

SETTING

Urine samples were collected at volunteers' homes throughout city of Albuquerque.

PATIENT(S)

110 women attempting to conceive spontaneously; 62 achieved pregnancies (42 to term and 20 failed).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Measurements of the total hCG and hCG-H, and calculations of the proportion of hCG-H.

RESULT(S)

In all 42 term pregnancies, the proportion of hCG-H on the day of implantation was >50%. This was also true for 7 of the 20 failures. Statistically significant lower proportions of hCG-H (<50%) were observed in 13 of 20 pregnancies that eventually failed. The predictive values of proportion of hCG-H, concentration of hCG-H, total hCG, and regular hCG alone for detecting failures were 100%, 59%, 41%, and 21%, respectively.

CONCLUSION(S)

Hyperglycosylated is produced by cytotrophoblast cells in early pregnancy at the time of implantation. Effective proportions of hCG-H (>50%) are required for successful growth and invasion by cytotrophoblasts at the time of implantation. Low proportions of hCG-H at implantation predict failure and are likely to be the root of many pregnancy failures. The 7 of 20 failures with normal proportions of hCG-H were likely due to genetic, immune, or maternal causes. Measurement of a proportion of hCG-H <50% on the day of implantation absolutely indicates a failing pregnancy.

Hyperglycosylated hCG

Hyperglycosylated hCG (hCG-H) is a glycosylation variant of the hormone hCG. Here we review all that is known about this independently functioning molecule. As discussed, it is a very different molecule to the hormone hCG. First, hCG-H is produced by cytotrophoblast cells while regular hCG is made in syncytiotrophoblast cell. Second, it is an autocrine acting directly on the cells which produce it, while regular hCG is an endocrine acting on maternal corpus luteal cells. Third, hCG-H has minimal biological activity in promoting progesterone production compared to regular hCG. Fourth, hCG-H functions unlike regular hCG as an invasion promoter, whether invasion as in choriocarcinoma and testicular germ cell malignancies, or as in implantation of pregnancy. These functions seemingly occur through action on cytotrophoblast cell TGFbeta receptors. Fifth, hCG-H is an essential component for successful human implantation to prevent early pregnancy loss and spontaneous abortion. Sixth, hCG-H is critical for promoting the midtrimester hemochorial implantation, and for preventing preeclampsia. Seventh, measurements of hCG-H have advantages over measurements of regular hCG or total hCG, in detecting pregnancy, pregnancy outcome (failing or term pregnancy), predicting preeclampsia in pregnancy, or as a tumor marker for gestational trophoblastic diseases.