hCG, five independent molecules

Widespread Distribution of Luteinizing Hormone/Choriogonadotropin Receptor in Human Juvenile Angiofibroma: Implications for a Sex-Specific Nasal Tumor

Juvenile angiofibroma (JA) is a rare, sex-specific, and highly vascularized nasal tumor that almost exclusively affects male adolescents, but its etiology has been controversial. The G protein-coupled hormone receptor LHCGR [luteinizing hormone (LH)/choriogonadotropin (hCG) receptor] represents a promising new candidate for elucidating the underlying mechanisms of sex specificity, pubertal manifestation, and JA progression. We used highly sensitive RNAscope technology, together with immunohistochemistry, to investigate the cellular expression, localization, and distribution of LHCGR in tissue samples from JA patients. Our results provide evidence for LHCGR expression in subsets of cells throughout JA tissue sections, with the majority of LHCGR+ cells located in close vicinity to blood vessels, rendering them susceptible to endocrine LH/hCG signaling, but LHCGR+ cells were also detected in fibrocollagenous stroma. A majority of LHCGR+ cells located near the vascular lumen co-expressed the neural crest stem cell marker CD271. These results are intriguing as both LH and hCG are produced in a time- and sex-dependent manner, and are known to be capable of inducing cell proliferation and angiogenesis. Our results give rise to a new model that suggests endocrine mechanisms involving LHCGR and its ligands, together with autocrine and paracrine signaling, in JA vascularization and cell proliferation.

Serum β-hCG as a Biomarker in Pancreatic Neuroendocrine Tumors: Rethinking Single-Analyte Approach

Despite recent advances, neuroendocrine tumors (NETs) remain a challenging topic, due to their diversity and the lack of suitable biomarkers. Multianalyte assays and the shift to an omics-based approach improve on the conventional single-analyte strategy, albeit with their own drawbacks. We explored the potential of serum β-hCG as a biomarker for NETs and discussed its role in disease monitoring. We recruited 40 patients with non-functioning pancreatic NETs, all with liver metastases. Serum β-hCG concentrations were measured at 3-month intervals over 48 months. We performed a comparative and a repeated measures analysis of β-hCG depending on WHO grade (G1, G2), liver tumor burden (LTB; below 10%, 10-25%), and RECIST 1.1. (stable disease, progressive disease). Patients with progressive disease (p < 0.001), 10-25% LTB (p < 0.001) and WHO Grade 2 (p < 0.001) displayed higher β-hCG concentrations. Throughout the study, β-hCG concentrations consistently increased across the entire cohort. Delta β-hCG during the study period was greater in patients with 10-25% LTB (p < 0.001), progressive disease (p < 0.001), and G2 (p = 0.003). Serum β-hCG correlates with established indicators of malignancy and disease progression in metastatic NETs, supporting further studies as a monitoring and prognostic biomarker. Despite promising results from novel biomarkers, there is still a place for single-analyte assays in NETs.

Total human chorionic gonadotropin is a more suitable diagnostic marker of gestational trophoblastic diseases than the free β-subunit of human chorionic gonadotropin

Objectives

Human chorionic gonadotropin (hCG) levels are essential for the management of trophoblastic diseases. This study aimed to compare the sensitivities and relationships of two hCG measurement methods (total hCG and the free β-subunit of hCG) in managing gestational trophoblastic disease (GTD).

Design and Methods

We analyzed data from patients treated for GTD at Chiba University Hospital between 2008 and 2019. We focused on cases where both total hCG (mIU/mL) and the free β-subunit of hCG (ng/mL) were measured on the same day.

Results

Out of 80 patients (mean age 38.9 ± 11.7 years) and 158 measurements, 26 had values below the sensitivity threshold for both tests. Fifty-nine measurements were positive for total hCG but below the sensitivity threshold for the free β-subunit of hCG, whereas only two showed the opposite. Seventy-one measurements were positive for both total hCG and the free β-subunit of hCG. There was a significant correlation between total hCG and the free β-subunit of hCG with both positive values, (r = 0.94, p < 0.001; Spearman's correlation test). Of the 85 measurements with undetectable free β-subunit levels, 26 also had undetectable total hCG levels. However, total hCG was detectable in 59 patients from these cases, with a median value (interquartile range) of 2.9 (1.75-4.9) mIU/mL.

Conclusions

In the management of GTD, the use of the free β-subunit system alone cannot be recommended.

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.

Biochemical Screening for Fetal Trisomy 21: Pathophysiology of Maternal Serum Markers and Involvement of the Placenta

It is now well established that maternal serum markers are often abnormal in fetal trisomy 21. Their determination is recommended for prenatal screening and pregnancy follow-up. However, mechanisms leading to abnormal maternal serum levels of such markers are still debated. Our objective was to help clinicians and scientists unravel the pathophysiology of these markers via a review of the main studies published in this field, both in vivo and in vitro, focusing on the six most widely used markers (hCG, its free subunit hCGβ, PAPP-A, AFP, uE3, and inhibin A) as well as cell-free feto-placental DNA. Analysis of the literature shows that mechanisms underlying each marker's regulation are multiple and not necessarily directly linked with the supernumerary chromosome 21. The crucial involvement of the placenta is also highlighted, which could be defective in one or several of its functions (turnover and apoptosis, endocrine production, and feto-maternal exchanges and transfer). These defects were neither constant nor specific for trisomy 21, and might be more or less pronounced, reflecting a high variability in placental immaturity and alteration. This explains why maternal serum markers can lack both specificity and sensitivity, and are thus restricted to screening.

A Search for Uniformity in Human Chorionic Gonadotropin (hCG) Reporting

Varying reports across different laboratories or across different analysers in the same lab for the same sample is not an uncommon phenomena. Experts call this a lack of harmonization. A test that is harmonized provides the same results regardless of the manufacturer of reagents used or the laboratory where the test is performed. When laboratory tests are not harmonized, the entire continuum of patient care can be affected in a number of ways. Here, we present a case of varying reports for a single serum human chorionic gonadotropin (hCG) sample on two different immunoassay platforms for a young female presenting with an abdominopelvic mass. The lab reports for serum hCG for this particular patient showed inconsistent results with the same sample within the same lab. The phenomena behind this was lack of harmonization of test results. We introspect many of the factors responsible for lack of uniformity in hCG results amongst the major ones being with use of antibodies directed against different epitopes of hCG (analyte) and the heterogeneity of the hCG molecule itself. Harmonization is a process to ensure that different clinical testing procedures used by different laboratories give equivalent results. Harmonizing test results will enable healthcare providers to use clinical guidelines with greater confidence for diagnosing disease and managing patients.

Expression and function of the luteinizing hormone choriogonadotropin receptor in human endometrial stromal cells

The human luteinising hormone choriogonadotropin receptor (LHCGR) is a G-protein coupled receptor activated by both human chorionic gonadotropin (hCG) and luteinizing hormone (LH), two structurally related gonadotropins with essential roles in ovulation and maintenance of the corpus luteum. LHCGR expression predominates in ovarian tissues where it elicits functional responses through cyclic adenosine mononucleotide (cAMP), Ca²⁺ and extracellular signal-regulated kinase (ERK) signalling. LHCGR expression has also been localized to the human endometrium, with purported roles in decidualization and implantation. However, these observations are contentious. In this investigation, transcripts encoding LHCGR were undetectable in bulk RNA sequencing datasets from whole cycling endometrial tissue and cultured human endometrial stromal cells (EnSC). However, analysis of single-cell RNA sequencing data revealed cell-to-cell transcriptional heterogeneity, and we identified a small subpopulation of stromal cells with detectable LHCGR transcripts. In HEK-293 cells expressing recombinant LHCGR, both hCG and LH elicited robust cAMP, Ca²⁺ and ERK signals that were absent in wild-type HEK-293 cells. However, none of these responses were recapitulated in primary EnSC cultures. In addition, proliferation, viability and decidual transformation of EnSC were refractory to both hCG and LH, irrespective of treatment to induce differentiation. Although we challenge the assertion that LHCGR is expressed at a functionally active level in the human endometrium, the discovery of a discrete subpopulation of EnSC that express LHCGR transcripts may plausibly account for the conflicting evidence in the literature.

Human chorionic gonadotrophin assays to monitor GTD

Hydatidiform mole (HM) occurs in 1:500-1000 pregnancies and are generally characterised as a benign proliferative disorder of chorionic villous trophoblast. HM belongs to the group of disorders, collectively known as gestational trophoblastic disease (GTD), which include invasive mole, choriocarcinoma, placental site trophoblastic tumour and epitheloid trophoblastic tumour. Patients with HM are at increased risk of developing these malignant forms and hence accurate diagnosis is very important for monitoring persistent diseases and informing correct patient management. In this review, we describe the current model for HM follow-up in the UK, with special emphasis on the in-house human chorionic gonadotrophin (hCG) radioimmunoassay (RIA) currently employed for monitoring women in our programme. We briefly discuss the structure, function and significance of hCG monitoring in GTD and the limitations and benefits of the current assays used for measuring oncology hCG. In particular, we describe the preliminary work evaluating a replacement antibody for the current gold-standard UK-RIA method.

Novel predictive and therapeutic options for better pregnancy outcome in frozen embryo transfer cycles

Since 1978, in the first decades of in vitro fertilization (IVF), the use of ovarian hyperstimulation allowed for the development and transfer of multiple embryos. As IVF technology improved, the number of multiple pregnancies increased, which led to gradual reduction in the number of embryos that were transferred. Embryo freezing (vitrification) was recommended to allow subsequent transfer if the fresh cycle was unsuccessful. However, experimentation has continued to improve pregnancy outcomes. We discuss here the significance of frozen embryo transfer cycle and the impact of uterine and peripheral immunity dominated by NK cells and regulatory T cells and human chorionic gonadotropin on pregnancy outcome in this innovative mode of IVF therapy.

The impact of hyaluronan-enriched culture medium and intrauterine infusion of human chorionic gonadotropin on clinical outcomes in blastocyst transfer cycles

Over the last few decades, advances in ovarian hormonal stimulation, embryology laboratory technologies and embryo genetic testing, have significantly enhanced clinical outcomes in human assisted reproduction technologies (ART). However, embryo implantation remains a major bottleneck in achieving better pregnancy and live birth rates. Thus, there is growing interest in establishing new approaches to enhance implantation efficiency after embryo transfer. With advanced molecular techniques, many promising biomarkers associated with embryonic and endometrial changes occurring prior to and during embryo implantation have been identified. However, despite the progress in applying novel procedures into IVF practice, clinical evaluation of those biomarkers has so far reached modest predictive value for enhancing blastocyst developmental potential and endometrial receptivity. Therefore, other simpler strategies have also been introduced to increase the rates of successful clinical pregnancies and live births. One of these approaches is to investigate the impact of using embryo transfer medium containing high concentrations of an adherence compound, such as hyaluronic acid (HA), on IVF outcomes. Additionally, intrauterine infusion of a small volume of human chorionic gonadotropin (hCG) at the time of embryo transfer (ET) has also been proposed as a technique that might be advantageous for increasing the clinical outcomes, considering the fact that hCG plays a critical role in synchronizing endometrial and fetal development. However, the current findings from both interventions remain controversial, demonstrating a mixture of positive and indifferent results of these treatments in ART cycles. Further research will be crucial for a better understanding of the molecular mechanism of cross-talk between the blastocyst and the maternal endometrium during the optimal implantation period when using either hyaluronan-enriched medium or hCG infusion before embryo transfers. Therefore, this review aims to present existing literature related to both treatments, emphasizing their effects on blastocyst implantation.Abbreviations: ART: assisted reproduction technologies; HA: hyaluronic acid; hCG: human chorionic gonadotrophin; IVF: in vitro Fertilization; ET: embryo transfer; pH: hydrogen ions; CO2: Carbone dioxide; O2: Oxygen; PGT: pre-implantation genetic testing; FET: frozen embryo transfer; PCOS: Polycystic ovarian syndrome; DNA: deoxyribonucleic acid; miRNA: micro-ribonucleic acid; EVs: extracellular vesicles; ERA: endometrial receptivity array; CD44 and RHAMM: primary hyaluronan surface receptors; RCT: randomized clinical trials; LBR: life birth rate; CPR: clinical pregnancy rate; IR: implantation rate.

Embryo Selection and Mate Choice: Can 'Honest Signals' Be Trusted?

When a measure becomes a target, it often ceases to be a good measure - an effect familiar from the declining usefulness of standardized testing in schools. This economic principle also applies to mate choice and, perhaps surprisingly, pregnancy. Just as females screen potential mates under many metrics, human mothers unconsciously screen embryos for quality. 'Examinees' are under intense selection to improve test performance by exaggerating formerly 'honest' signals of quality. Examiners must change their screening criteria to maintain useful information (but cannot abandon old criteria unilaterally). By the resulting 'proxy treadmill', new honest indicators arise while old degraded indicators linger, resulting in trait elaboration and exaggeration. Hormone signals during pregnancy show extreme evolutionary escalation (akin to elaborate mating displays).

Human Chorionic Gonadotropin-Mediated Immune Responses That Facilitate Embryo Implantation and Placentation

Human chorionic gonadotropin (hCG) serves as one of the first signals provided by the embryo to the mother. Exactly at the time when the first step of the implantation process is initiated and the blastocyst adheres to the maternal endometrium, the embryonic tissue starts to actively secrete hCG. Shortly thereafter, the hormone can be detected in the maternal circulation where its concentration steadily increases throughout early pregnancy as it is continuously released by the forming placenta. Accumulating evidence underlines the critical function of hCG for embryo implantation and placentation. hCG not only regulates biological aspects of these early pregnancy events but also supports maternal immune cells in their function as helpers in the establishment of an adequate embryo-endometrial relationship. In view of its early presence in the maternal circulation, hCG has the potential to influence both local uterine immune cell populations as well as peripheral ones. The current review aims to summarize recent literature on the participation of innate and adaptive immune cells in embryo implantation and placentation with a specific focus on their regulation by hCG.

Assessment of endocrine disruptor effects of levonorgestrel and its photoproducts: Environmental implications of released fractions after their photocatalytic removal

The presence of levonorgestrel (LNG) in water bodies via direct discharge and human excretion has been reported worldwide, but its effects on the reproduction of aquatic species and humans are still unknown. Owing to its recalcitrant properties, LNG is not completely removed during wastewater treatment plants, and many species may be exposed to low traces of this compound from discharged effluents. Thus, in this study, a photocatalytic process for removing LNG along with screening of endocrine disruptor effects for risk assessment was applied. Although the removal rate of LNG by ultraviolet C (UV-C) radiation was >90%, reproductive toxicity testing using the BeWo cell line exposed to LNG and its degraded fraction showed the reduced production of basal human chorionic gonadotropin hormone (β-hCG) by more than 73%, from 8.90 mIU mL^-1 to <2.39 mIU mL^-1, with both LNG and the degraded fraction. β-hCG hormone has been implicated in the viability of trophoblastic cells during the first trimester of pregnancy; therefore, degraded fractions and waterborne LNG may affect reproduction in some aquatic species and humans with low level of exposure.

Intrauterine infusion of human chorionic gonadotropin before embryo transfer in IVF/ET cycle: The critical review

Intrauterine infusion of human chorionic gonadotropin (IUI-hCG) has been proposed to improve the outcome of in vitro fertilization-embryo transfer (IVF-ET), since it plays a critical role in synchronizing endometrial and fetal development. As the early mediator from embryo, hCG promotes the decidualization, angiogenesis, maternal immune tolerance, and trophoblast invasion, favoring successful implantation of embryo. Although multiple clinical trials have been conducted to verify the efficacy of IUI-hCG on IVF-ET outcome in recent years, the findings remained controversial. The difference in study design and population might be the cause to the different consequences after administration of hCG. More importantly, the endometrial receptivity, which might affect the efficacy of IUI-hCG, has not been assessed in women receiving this intervention. Selecting the right population suitable for IUI-hCG based on known etiology would be crucial in enhancing its efficacy and minimize any possible complications. Investigation of optimal indications for IUI-hCG should be highlighted in the future.

β-hCG promotes epithelial ovarian cancer metastasis through ERK/MMP2 signaling pathway

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy, with typically extensive intraperitoneal implantation leading to poor prognosis. Our previous study preliminarily demonstrated β-hCG can promote tumorigenesis in immortalized nontumorigenic ovarian epithelial cells. In this study, the roles and mechanisms of β-hCG in regulating EOC proliferation and metastasis were thoroughly explored. First, histologically, β-hCG was aberrantly overexpressed in human EOC metastatic tissues, and significantly correlated with FIGO stage, tumor size, differentiation, histologic grade and high grade serous ovarian carcinoma (HGSOC) (P < 0.05). However, serologically, β-hCG expression showed no significant difference between EOC and nonmalignant ovarian patients. Second, β-hCG was confirmed to have no significant effects on EOC proliferation in vitro and in vivo, while β-hCG upregulation was proven to promote migration and invasion ability in ES-2 and OVCAR-3 cells in vitro (P < 0.05), and β-hCG downregulation in SKOV3 cells had the opposite effect. Moreover, more invadopodia protrusions, mitochondria accumulations and cytoskeletal rearrangements were observed in β-hCG-overexpressing ES-2 cells, while β-hCG-depleted SKOV3 cells produced the opposite effect. Furthermore, β-hCG was confirmed to clearly facilitate intraperitoneal metastasis in nude mouse orthotopic ovarian xenograft models. Importantly, these effects of β-hCG were mediated by activation of the ERK/MMP2 signaling pathway, independently of luteinizing hormone/chorionic gonadotropin receptor (LHCGR) presence, and inhibition the pathway with the p-ERK1/2 inhibitor SCH772984 significantly impaired the tumor-promoting effects induced by β-hCG. Collectively, these data provide new insight into the roles and mechanisms of β-hCG in regulating EOC metastasis through ERK/MMP2 signaling pathway and may become a new target for therapeutic intervention.

Two Hormones for One Receptor: Evolution, Biochemistry, Actions, and Pathophysiology of LH and hCG

LH and chorionic gonadotropin (CG) are glycoproteins fundamental to sexual development and reproduction. Because they act on the same receptor (LHCGR), the general consensus has been that LH and human CG (hCG) are equivalent. However, separate evolution of LHβ and hCGβ subunits occurred in primates, resulting in two molecules sharing ~85% identity and regulating different physiological events. Pituitary, pulsatile LH production results in an ~90-minute half-life molecule targeting the gonads to regulate gametogenesis and androgen synthesis. Trophoblast hCG, the "pregnancy hormone," exists in several isoforms and glycosylation variants with long half-lives (hours) and angiogenic potential and acts on luteinized ovarian cells as progestational. The different molecular features of LH and hCG lead to hormone-specific LHCGR binding and intracellular signaling cascades. In ovarian cells, LH action is preferentially exerted through kinases, phosphorylated extracellular-regulated kinase 1/2 (pERK1/2) and phosphorylated AKT (also known as protein kinase B), resulting in irreplaceable proliferative/antiapoptotic signals and partial agonism on progesterone production in vitro. In contrast, hCG displays notable cAMP/protein kinase A (PKA)-mediated steroidogenic and proapoptotic potential, which is masked by estrogen action in vivo. In vitro data have been confirmed by a large data set from assisted reproduction, because the steroidogenic potential of hCG positively affects the number of retrieved oocytes, and LH affects the pregnancy rate (per oocyte number). Leydig cell in vitro exposure to hCG results in qualitatively similar cAMP/PKA and pERK1/2 activation compared with LH and testosterone. The supposed equivalence of LH and hCG has been disproved by such data, highlighting their sex-specific functions and thus deeming it an oversight caused by incomplete understanding of clinical data.

Heterogeneous hCG and hMG commercial preparations result in different intracellular signalling but induce a similar long-term progesterone response in vitro

STUDY QUESTION

Are four urinary hCG/menotropin (hMG) and one recombinant preparation characterized by different molecular features and do they mediate specific intracellular signaling and steroidogenesis?

SUMMARY ANSWER

hCG and hMG preparations have heterogeneous compositions and mediate preparation-specific cell signaling and early steroidogenesis, although similar progesterone plateau levels are achieved in 24 h-treated human primary granulosa cells in vitro.

WHAT IS KNOWN ALREADY

hCG is the pregnancy hormone marketed as a drug for ARTs to induce final oocyte maturation and ovulation, and to support FSH action. Several hCG formulations are commercially available, differing in source, purification methods and biochemical composition.

STUDY DESIGN, SIZE, DURATION

Commercial hCG preparations for ART or research purposes were compared in vitro.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The different preparations were quantified by immunoassay with calibration against the hCG standard (Fifth IS; NIBSC 07/364). Immunoreactivity patterns, isoelectric points and oligosaccharide contents of hCGs were evaluated using reducing and non-reducing Western blotting, capillary isoelectric-focusing immunoassay and lectin-ELISA, respectively. Functional studies were performed in order to evaluate intracellular and total cAMP, progesterone production and β-arrestin 2 recruitment by ELISA and BRET, in both human primary granulosa lutein cells (hGLC) and luteinizing hormone (LH)/hCG receptor (LHCGR)-transfected HEK293 cells, stimulated by increasing hormone concentrations. Statistical analysis was performed using two-way ANOVA and Bonferroni post-test or Mann-Whitney's U-test as appropriate.

MAIN RESULTS AND THE ROLE OF CHANCE

Heterogeneous profiles were found among preparations, revealing specific molecular weight patterns (20-75 KDa range), isoelectric points (4.0-9.0 pI range) and lectin binding (P < 0.05; n = 7-10). These drug-specific compositions were linked to different potencies on cAMP production (EC50 1.0-400.0 ng/ml range) and β-arrestin 2 recruitment (EC50 0.03-2.0 μg/ml) in hGLC and transfected HEK293 cells (P < 0.05; n = 3-5). In hGLC, these differences were reflected by preparation-specific 8-h progesterone production although similar plateau levels of progesterone were acheived by 24-h treatment (P ≥ 0.05; n = 3).

LARGE SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

The biological activity of commercial hCG/hMG preparations is provided in International Units (IU) by in-vivo bioassay and calibration against an International Standard, although it is an unsuitable unit of measure for in-vitro studies. The re-calibration against recombinant hCG,quantified in grams, is based on the assumption that all of the isoforms and glycosylation variants have similar immunoreactivity.

WIDER IMPLICATIONS OF THE FINDINGS

hCG/hMG preparation-specific cell responses in vitro may be proposed to ART patients affected by peculiar ovarian response, such as that caused by polycystic ovary syndrome. Otherwise, all the preparations available for ART may provide a similar clinical outcome in healthy women.

STUDY FUNDING AND COMPETING INTEREST(S)

This study was supported by a grant of the Italian Ministry of Education, University and Research (PRIN 2015XCR88M). The authors have no conflict of interest.

Label-Free Sensors Based on Graphene Field-Effect Transistors for the Detection of Human Chorionic Gonadotropin Cancer Risk Biomarker

We report on the development of label-free chemical vapour deposition (CVD) graphene field effect transistor (GFET) immunosensors for the sensitive detection of Human Chorionic Gonadotropin (hCG), a glycoprotein risk biomarker of certain cancers. The GFET sensors were fabricated on Si/SiO₂ substrate using photolithography with evaporated chromium and sputtered gold contacts. GFET channels were functionalised with a linker molecule to an immobile anti-hCG antibody on the surface of graphene. The binding reaction of the antibody with varying concentration levels of hCG antigen demonstrated the limit of detection of the GFET sensors to be below 1 pg/mL using four-probe electrical measurements. We also show that annealing can significantly improve the carrier transport properties of GFETs and shift the Dirac point (Fermi level) with reduced p-doping in back-gated measurements. The developed GFET biosensors are generic and could find applications in a broad range of medical diagnostics in addition to cancer, such as neurodegenerative (Alzheimer's and Parkinson's ) and cardiovascular disorders.

Lowered reference limits for hCG improve follow-up of patients with hCG-producing tumors

BACKGROUND

Human Chorionic Gonadotropin (hCG) is produced by germ cell tumors, but can also be elevated in benign conditions such as primary hypogonadism, where hCG is produced by the pituitary gland. In our experience, the reference limits for hCG (Elecsys hCG+β-assay, Roche Diagnostics), were unnecessarily high and did not reflect levels encountered in clinical practice. We wanted to establish new reference limits to increase the clinical utility of the hCG-assay.

METHODS

We analysed hCG in serum samples from a healthy adult population and in a cohort of testicular cancer survivors. The gonadotropins LH and FSH were measured in the cohort and in a selection of the reference population to assess gonadal function.

RESULTS

We found low hCG levels for all men and women <45years (97.5 percentiles 0.1 and 0.2IU/L, respectively) from the healthy population (n=795) having normal FSH and LH. Due to assay limitations, we suggest a common reference limit of <0.3IU/L. For the age group ≥45, the 97.5 percentiles in the healthy population were 0.5IU/L for men and 6.0IU/L for women. In all subjects from both the reference population and the cohort (n=732), hCG levels exceeding the reference limit could be fully explained by reduced gonadal function indicated by elevated LH and FSH levels.

CONCLUSION

The Elecsys hCG+β-assay should have lower reference limits than recommended by the manufacturer, with important implications for tumor follow-up. Elevated hCG is rare with intact gonadal function, both in a normal population and among survivors of testicular cancer, and should lead to further investigations when encountered in clinical practice.

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.

The effect of human chorionic gonadotrophin contained in human menopausal gonadotropin on the clinical outcomes during progestin-primed ovarian stimulation

Progestin-primed ovarian stimulation (PPOS) protocol has recently been demonstrated to be an novel regimen for preventing premature LH surges during controlled ovarian hyperstimulation (COH) in combination with frozen-thawed embryo transfer (FET). Our prospective controlled study was to explore the effect of human chorionic gonadotropin (hCG) contained in human menopausal gonadotropin (hMG) on the clinical outcomes in normalovulatory women undergoing COH with PPOS. A total of 180 patients were allocated into three groups according to the gonadotropin (Gn) used: group A (human menopausal gonadotropin, hMG-A), group B (hMG-B) or group C (follicle stimulating hormone, FSH). The primary outcome measured was the number of oocytes retrieved. The number of oocytes retrieved in group A B C was 10.72±5.78 11.33±5.19and13.38±8.97, respectively, with no statistic significance (p>0.05). Other embryological indicators were also similar (p>0.05). The concentration of serum and urinary β-hCG on the trigger day in group A and B were not associated with embryo results (p>0.05). There was no significant differences in the clinical pregnancy rate (41.67% vs. 51.56% vs. 39.51%, p>0.05) and implantation rate (31.58%vs. 34.75%vs.25.33%) after FET among the three groups. Thus the clinical characteristics were not affected by the hCG contained in hMG in normalovulatory women treated with PPOS.

The Role of HCG in Implantation: A Mini-Review of Molecular and Clinical Evidence

Embryo implantation is a complex process involving continuous molecular cross-talk between the embryo and the decidua. One of the key molecules during this process is human chorionic gonadotropin (HCG). HCG effectively modulates several metabolic pathways within the decidua contributing to endometrial receptivity. Herein, a brief overview of the molecular mechanisms regulated by HCG is presented. Furthermore, we summarize the existing evidence regarding the clinical impact on reproductive outcomes after endometrial priming with HCG prior to embryo transfer. Although promising, further evidence is needed to clarify the protocol that would lead to beneficial outcomes.

Analysis of first-trimester combined test results in preparation for a cell-free fetal DNA era

OBJECTIVE

To survey experience with the first-trimester combined test (FCT) for trisomy 21 (T21) in different risk score groups to determine the most useful clinical application of cell-free fetal DNA (cffDNA) screening.

METHODS

In a retrospective study, the records of FCT results obtained at a center in Turkey between January 2009 and January 2014 were reviewed. The FCT results and rates of uptake of invasive diagnostic testing were compared among different risk score groups.

RESULTS

FCT results were available for 4804 pregnancies; 276 (5.7%) had IDT results. Ten (72.7%) of 11 cases of T21 had a risk score of 1:300 or more. The IDT uptake rates were 54.5%, 51.9%, and 47.4% at risk scores of 1:100 or more, 1:200 or more, and 1:300 or more, respectively. In the group at intermediate risk (1:1001-1:3000), no pregnancy had an FCT result of both low pregnancy-associated plasma protein A and high free β-human chorionic gonadotropin, but 30 (3.9%) of 766 pregnancies had both advanced maternal age and high β-human chorionic gonadotropin.

CONCLUSION

cffDNA screening should be used to optimize IDT uptake in pregnancies with a risk score of 1:101-1:1000. The selective power of the FCT diminishes beyond the 1:1001 score and cffDNA screening cannot yet be recommended routinely.

Micro-dose hCG as luteal phase support without exogenous progesterone administration: mathematical modelling of the hCG concentration in circulation and initial clinical experience

For the last two decades, exogenous progesterone administration has been used as luteal phase support (LPS) in connection with controlled ovarian stimulation combined with use of the human chorionic gonadotropin (hCG) trigger for the final maturation of follicles. The introduction of the GnRHa trigger to induce ovulation showed that exogenous progesterone administration without hCG supplementation was insufficient to obtain satisfactory pregnancy rates. This has prompted development of alternative strategies for LPS. Augmenting the local endogenous production of progesterone by the multiple corpora lutea has been one focus with emphasis on one hand to avoid development of ovarian hyper-stimulation syndrome and, on the other hand, to provide adequate levels of progesterone to sustain implantation. The present study evaluates the use of micro-dose hCG for LPS support and examines the potential advances and disadvantages. Based on the pharmacokinetic characteristics of hCG, the mathematical modelling of the concentration profiles of hCG during the luteal phase has been evaluated in connection with several different approaches for hCG administration as LPS. It is suggested that the currently employed LPS provided in connection with the GnRHa trigger (i.e. 1.500 IU) is too strong, and that daily micro-dose hCG administration is likely to provide an optimised LPS with the current available drugs. Initial clinical results with the micro-dose hCG approach are presented.

The spatiotemporal hormonal orchestration of human folliculogenesis, early embryogenesis and blastocyst implantation

The early reproductive events starting with folliculogenesis and ending with blastocyst implantation into the uterine endometrium are regulated by a complex interplay among endocrine, paracrine and autocrine factors. This review examines the spatiotemporal integration of these maternal and embryonic signals that are required for successful reproduction. In coordination with hypothalamic-pituitary-gonadal (HPG) hormones, an intraovarian HPG-like axis regulates folliculogenesis, follicular quiescence, ovulation, follicular atresia, and corpus luteal functions. Upon conception and passage of the zygote through the fallopian tube, the contribution of maternal hormones in the form of paracrine secretions from the endosalpinx to embryonic development declines, with autocrine and paracrine signaling becoming increasingly important as instructional signals for the differentiation of the early zygote/morula into a blastocyst. These maternal and embryonic signals include activin and gonadotropin-releasing hormone 1 (GnRH1) that are crucial for the synthesis and secretion of the 'pregnancy' hormone human chorionic gonadotropin (hCG). hCG in turn signals pre-implantation embryonic cell division and sex steroid production required for stem cell differentiation, and subsequent blastulation, gastrulation, cavitation and blastocyst formation. Upon reaching the uterus, blastocyst hatching occurs under the influence of decreased activin signaling, while the attachment and invasion of the trophoblast into the endometrium appears to be driven by a decrease in activin signaling, and by increased GnRH1 and hCG signaling that allows for tissue remodeling and the controlled invasion of the blastocyst into the uterine endometrium. This review demonstrates the importance of integrative endocrine, paracrine, and autocrine signaling for successful human reproduction.

Persistent low levels of serum hCG due to heterophilic mouse antibodies: an unrecognized pitfall in the diagnosis of trophoblastic disease

Phantom hCG refers to persistent mild elevations of hCG, leading physicians to unnecessary treatments whereas neither a true hCG nor a trophoblastic disease is present. We report the case of a 23-year-old woman with persistent low levels of serum hCG detected one month after miscarriage. As choriocarcinoma was suspected, a chemotherapy trial of methotrexate was prescribed, without any hCG reduction. Subsequently, laparoscopy ruled out a trophoblastic residue and the patient was referred to the Endocrine Unit for further investigations. While low levels of hCG were still detected in serum, no hCG was detected in the urine. In addition, when serum was processed in a HBT tube for revealing heterophilic antibodies, hCG was no longer detected. Such finding indicated the presence of phantom hCG due to heterophilic mouse antibodies interaction. This case raises the need of clinico-biological discussion to avoid inappropriate therapeutic decisions. Based on this case experience and after review of the literature, we suggest that current gynecological protocols for the diagnosis and treatment of trophoblastic disease should consider the inclusion of urinary hCG and/or a test for serum heterophilic antibodies when appropriate.

Human chorionic gonadotropin β subunit affects the expression of apoptosis-regulating factors in ovarian cancer

Expression of human chorionic gonadotropin, especially its free β subunit (hCGβ) were shown to play an important role in cancer growth, invasion and metastasis. It is postulated that hCGβ is one of the factors determining cancer cell survival. To test this hypothesis, we applied two models: an in vitro model of ovarian cancer using OVCAR-3 and SKOV-3 cell lines transfected with the CGB5 gene and an in vivo model of ovarian cancer tissues. The material was tested against changes in expression level of genes encoding factors involved in apoptosis: BCL2, BAX and BIRC5. Overexpression of hCGβ was found to cause a decrease in expression of the analyzed genes in the transfected cells compared with the control cells. In ovarian cancer tissues, high expression of CGB was related to significantly lower BCL2 but higher BAX and BIRC5 transcript levels. Moreover, a low BCL2/BAX ratio, characteristic of advanced stages of ovarian cancer, was revealed. Since tumors were discriminated by a significantly lower LHCGR level than the level noted in healthy fallopian tubes and ovaries, it may be stated that the effect of hCGβ on changes in the expression of apoptosis-regulating agents observed in ovarian cancer is LHCGR-independent. The results of the study suggest that the biological effects evoked by hCGβ are related to apoptosis suppression.

Recognition of N-glycoforms in human chorionic gonadotropin by monoclonal antibodies and their interaction motifs

The glycosylation of human chorionic gonadotropin (hCG) plays an important role in reproductive tumors. Detecting hCG N-glycosylation alteration may significantly improve the diagnostic accuracy and sensitivity of related cancers. However, developing an immunoassay directly against the N-linked oligosaccharides is unlikely because of the heterogeneity and low immunogenicity of carbohydrates. Here, we report a hydrogen/deuterium exchange and MS approach to investigate the effect of N-glycosylation on the binding of antibodies against different hCG glycoforms. Hyperglycosylated hCG was purified from the urine of invasive mole patients, and the structure of its N-linked oligosaccharides was confirmed to be more branched by MS. The binding kinetics of the anti-hCG antibodies MCA329 and MCA1024 against hCG and hyperglycosylated hCG were compared using biolayer interferometry. The binding affinity of MCA1024 changed significantly in response to the alteration of hCG N-linked oligosaccharides. Hydrogen/deuterium exchange-MS reveals that the peptide β65-83 of the hCG β subunit is the epitope for MCA1024. Site-specific N-glycosylation analysis suggests that N-linked oligosaccharides at Asn-13 and Asn-30 on the β subunit affect the binding affinity of MCA1024. These results prove that some antibodies are sensitive to the structural change of N-linked oligosaccharides, whereas others are not affected by N-glycosylation. It is promising to improve glycoprotein biomarker-based cancer diagnostics by developing combined immunoassays that can determine the level of protein and measure the degree of N-glycosylation simultaneously.

BMP4 regulation of human trophoblast development

Since the derivation of human embryonic stem cells, and the subsequent generation of induced pluripotent stem cells, there has been much excitement about the ability to model and evaluate human organ development in vitro. The finding that these cells, when treated with BMP4, are able to generate the extraembryonic cell type, trophoblast, which is the predominant functional epithelium in the placenta, has not been widely accepted. This review evaluates this model, providing comparison to early known events during placentation in both human and mouse and addresses specific challenges. Keeping in mind the ultimate goal of understanding human placental development and pregnancy disorders, our aim here is two-fold: to distinguish gaps in our knowledge arising from mis- or over-interpretation of data, and to recognize the limitations of both mouse and human models, but to work within those limitations towards the ultimate goal.

Signaling pathways in mouse and human trophoblast differentiation: a comparative review

The mouse is often used as a model for understanding human placentation and offers multiple advantages, including the ability to manipulate gene expression in specific compartments and to derive trophoblast stem cells, which can be maintained or differentiated in vitro. Nevertheless, there are numerous differences between the mouse and human placentas, only the least of which are structural. This review aims to compare mouse and human placentation, with a focus on signaling pathways involved in trophoblast lineage-specific differentiation.

Human embryonic stem cells carrying an unbalanced translocation demonstrate impaired differentiation into trophoblasts: an in vitro model of human implantation failure

Carriers of the balanced translocation t(11;22), the most common reciprocal translocation in humans, are at high risk of creating gametes with unbalanced translocation, leading to repeated miscarriages. Current research models for studying translocated embryos and the biological basis for their implantation failure are limited. The aim of this study was to elucidate whether human embryonic stem cells (hESCs) carrying the unbalanced chromosomal translocation t(11;22) can provide an explanation for repeated miscarriages of unbalanced translocated embryos. Fluorescent in situ hybridization and karyotype analysis were performed to analyze the t(11;22) in embryos during PGD and in the derived hESC line. The hESC line was characterized by RT-PCR and FACS analysis for pluripotent markers. Directed differentiation to trophoblasts was carried out by bone morphogenetic protein 4 (BMP4). Trophoblast development was analyzed by measuring β-hCG secretion, by β-hCG immunostaining and by gene expression of trophoblastic markers. We derived the first hESC line carrying unbalanced t(11;22), which showed the typical morphological and molecular characteristics of a hESC line. Control hESCs differentiated into trophoblasts secreted increasing levels of β-hCG and concomitantly expressed the trophoblast genes, CDX2, TP63, KRT7, ERVW1, CGA, GCM1, KLF4 and PPARG. In contrast, differentiated translocated hESCs displayed reduced and delayed secretion of β-hCG concomitant with impaired expression of the trophoblastic genes. The reduced activation of trophoblastic genes may be responsible for the impaired trophoblastic differentiation in t(11;22)-hESCs, associated with implantation failure in unbalanced t(11;22) embryos. Our t(11;22) hESCs are presented as a valuable human model for studying the mechanisms underlying implantation failure.

Immunoextraction-tandem mass spectrometry method for measuring intact human chorionic gonadotropin, free β-subunit, and β-subunit core fragment in urine

BACKGROUND

Human chorionic gonadotropin (hCG) stimulates testosterone production by the testicles. Because of the potential for abuse, hCG is banned (males only) in most sports and has been placed on the World Anti-Doping Agency list of prohibited substances. Intact hCG, free β-subunit (hCGβ), and β-subunit core fragment (hCGβcf) are the major variants or isoforms in urine. Immunoassays are used by antidoping laboratories to measure urinary hCG. Cross-reactivity with isoforms differs among immunoassays, resulting in widely varying results. We developed a sequential immunoextraction method with LC-MS/MS detection for quantification of intact hCG, hCGβ, and hCGβcf in urine.

METHODS

hCG isoforms were immunoextracted with antibody-conjugated magnetic beads and digested with trypsin, and hCGβ and hCGβcf unique peptides were quantified by LC-MS/MS with the corresponding heavy peptides as internal standard. hCG isoform concentrations were determined in urine after administration of hCG, and the intact hCG results were compared to immunoassay results.

RESULTS

The method was linear to 20 IU/L. Total imprecision was 6.6%-13.7% (CV), recovery ranged from 91% to 109%, and the limit of quantification was 0.2 IU/L. Intact hCG predominated in the urine after administration of 2 hCG formulations. The window of detection ranged from 6 to 9 days. Mean immunoassay results were 12.4-15.5 IU/L higher than LC-MS/MS results.

CONCLUSIONS

The performance characteristics of the method are acceptable for measuring hCG isoforms, and the method can quantify intact hCG and hCGβ separately. The limit of quantification will allow LC-MS/MS hCG reference intervals to be established in nondoping male athletes for improved doping control.

Chemical synthesis of the β-subunit of human luteinizing (hLH) and chorionic gonadotropin (hCG) glycoprotein hormones

Human luteinizing hormone (hLH) and human chorionic gonadotropin (hCG) are human glycoprotein hormones each consisting of two subunits, an identical α-subunit and a unique β-subunit, that form noncovalent heterodimers. Structurally, β-hCG shares a high degree of sequence similarity with β-hLH, including a common N-glycosylation site at the N-terminus but differs mainly in the presence of an extended C-terminal portion incorporating four closely spaced O-linked glycans. These glycoproteins play important roles in reproduction and are used clinically in the treatment of infertility. In addition, the role of hCG as a tumor marker in a variety of cancers has also attracted significant interest for the development of cancer vaccines. In clinical applications, these hormones are administered as mixtures of glycoforms due to limitations of biological methods in producing homogeneous samples of these glycoproteins. Using the powerful tools of chemical synthesis, the work presented herein focuses on the highly convergent syntheses of homogeneous β-hLH and β-hCG bearing model glycans at all native glycosylation sites. Key steps in these syntheses include a successful double Lansbury glycosylation en route to the N-terminal fragment of β-hCG and the sequential installation of four O-linked glycosyl-amino acid cassettes into closely spaced O-glycosylation sites in a single, high-yielding solid-supported synthesis to access the C-terminal portion of the molecule. The final assembly of the individual glycopeptide fragments involved a stepwise native chemical ligation strategy to provide the longest and most complex human glycoprotein hormone (β-hCG) as well as its closely related homologue (β-hLH) as discrete glycoforms.

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.

The interplay of human chorionic gonadotropin (hCG) with basic fibroblast growth factor and adipokines on angiogenesis in vitro

INTRODUCTION

Human chorionic gonadotropin (hCG) is suggested to regulate placental angiogenesis, however, its role is incompletely understood. hCG may directly stimulate angiogenesis or influence the effect of other angiogenic factors. We examined the effect of hCG and the interplay of hCG with basic fibroblast growth factor (bFGF) and with various adipokines on proliferation of vascular endothelial cells in vitro.

METHODS

Human umbilical vein endothelial cells (HUVEC) were incubated for 2 days with combinations of hCG, bFGF, leptin, resistin, adiponectin, IL6 and TNFα. Incorporation of radiolabelled thymidine was used to assess cell proliferation. Immunofluorescence and flow cytometry were used to examine activation of p44/42 mitogen-activated kinase (MAPK).

RESULTS

hCG induced proliferation of HUVEC alone and in combination with bFGF. Cells exposed to both hCG and bFGF displayed increased activation of p44/42 MAPK as compared to hCG or bFGF alone. Increased HUVEC proliferation was observed in the presence of increasing concentrations of leptin, resistin, adiponectin, and IL6, whereas HUVEC proliferation decreased in the presence of TNFα. hCG in combination with leptin, resistin, adiponectin or IL6 stimulated HUVEC proliferation beyond the effect of hCG alone.

DISCUSSION

An interplay of hCG with adipose tissue-derived factors with angiogenic properties is plausible. Thus, maternal obesity may affect placental angiogenesis in pregnancy.

CONCLUSIONS

hCG may directly stimulate angiogenesis. Also, hCG may indirectly stimulate angiogenesis through interplay with bFGF and adipokines.

Comparison of two direct neutralizing assay formats using recombinant follicle-stimulating hormone as agonist

Characterizing anti-drug antibodies for neutralizing activity is commonly part of the immunogenicity testing package for most therapeutic proteins. Cell-based neutralization assays can generally be categorized as direct- or indirect assays depending on whether they are associated with therapeutics with agonistic- or antagonistic properties. This paper's aim is a comparison of the two direct neutralization assay formats; the variable- and fixed concentration assay format, using recombinant follicle-stimulating hormone as drug agonist. Essential validation- and performance parameters, such as sample through-put, cut-point, precision, sensitivity and drug tolerance, were compared. The fixed concentration assay format offers superior sample through-put (40 versus 6 samples), precision (coefficient of variation of ≤14% versus 34%) and almost 6 times better sensitivity and is generally recommended as the better option particularly for quasi-quantitative assessments of neutralizing antibodies.

Glycoprotein disease markers and single protein-omics

Glycoproteins are well represented among biomarkers for inflammatory and cancer diseases. Secreted and membrane-associated glycoproteins make excellent targets for noninvasive detection. In this review, we discuss clinically applicable markers of cancer diseases and methods for their analysis. High throughput discovery continues to supply marker candidates with unusual glycan structures, altered glycoprotein abundance, or distribution of site-specific glycoforms. Improved analytical methods are needed to unlock the potential of these discoveries in validated clinical assays. A new generation of targeted quantitative assays is expected to advance the use of glycoproteins in early detection of diseases, molecular disease classification, and monitoring of therapeutic interventions.

Hyperglycosylated human chorionic gonadotropin does not increase progesterone production by luteinized granulosa cells

CONTEXT

Trophoblast-derived human chorionic gonadotropin (hCG) promotes corpus luteum progesterone (P4) production, and wide ranges of serum P4 levels are noted in various pregnancy outcomes, despite similar hCG concentrations. There are five unique biologically active hCG variants in human pregnancy urine, and previous studies of P4 production in response to hCG have used only preparations containing all isoforms. Understanding exactly which hCG variant is primarily responsible for stimulating corpus luteum steroidogenesis may have great clinical and diagnostic implications, including in the setting of ectopic pregnancy.

OBJECTIVE

Our objective was to delineate the role of the standard and hyperglycosylated (H)-hCG isoforms in stimulating P4 production by luteinized granulosa cells.

DESIGN AND SETTING

Cell culture, ELISA, and fluorometric-based protein assays were done at Duke University Medical Center.

PATIENTS

Patients were anonymous oocyte donors.

INTERVENTION

Cultured luteinized granulosa cells were treated with 0.25, 0.5, and 1.0 ng/ml total hCG, which contains all isoforms, purified standard hCG (37.1 kDa), and purified H-hCG (42.8 kDa).

MAIN OUTCOME MEASURE

P4 produced per total cellular protein (nanograms per microgram) was measured via ELISA and fluorometric protein determination kits.

RESULTS

Both total hCG (P = 0.0003) and purified standard hCG (P < 0.0001) stimulated a dose-dependent increase in P4 production. Purified H-hCG did not change the P4 produced per total cellular protein response (P value not significant).

CONCLUSIONS

Standard hCG stimulated P4 production by cultured granulosa cells and likely supports corpus luteum function via interactions with the LH/hCG receptor. In contrast, H-hCG did not increase P4 production, which indicates a nonsteroidogenic role for this protein during early gestation.