Significance of pro-angiogenic estrogen metabolites in normal follicular development and follicular growth arrest in polycystic ovary syndrome.

STUDY QUESTION: Do alterations in pro- and anti-angiogenic estrogen metabolites in follicular fluid (FF) contribute to the follicular growth arrest and anovulation associated with polycystic ovary syndrome (PCOS)? SUMMARY ANSWER: FF of PCOS women with anovulation have reduced levels of pro-angiogenic estrogen metabolites (EMs) and vascular endothelial growth factor (VEGF) compared to that of fertile women with regular menstrual cycles, but exogenous gonadotropins increase the pro-angiogenic EMs and VEGF levels in PCOS women. WHAT IS KNOWN ALREADY: PCOS is characterized by the arrest of follicular development that leads to chronic anovulation. Follicular arrest is generally associated with elevated plasma levels of luteinizing hormone (LH), androgens and anti-Mullerian hormone (AMH). There is also reduced angiogenesis in the follicles of PCOS women compared to those of normal cycling women. It is known that angiogenesis is a critical factor during follicular development. We and other investigators have explored the role of EMs in ovarian angiogenesis, particularly in human corpus luteum function, showing that 4-hydroxyestrone (4-OHE1) and 16-ketoestradiol (16-kE2) have pro-angiogenic effects while 2-methoxyestradiol (2-ME2) and 2-methoxyestrone (2-ME1) have anti-angiogenic effects. Additionally, 2-hydroxyestradiol (2-OHE2), which is produced in the ovary, has proliferative and pro-angiogenic properties. We hypothesized that EMs could be involved in angiogenesis necessary for ovarian follicular development in fertile women, and that dysregulation of these factors may contribute to follicular arrest in PCOS. The relationship between EMs, VEGF and AMH in the pathophysiology of follicular arrest in PCOS has not been previously studied at a follicular level in anovulatory women without ovulation induction. STUDY DESIGN, SIZE, DURATION: This is a comparative experimental study of serum and FF collected from different sized follicles (antral ˂10 mm and dominant ˃16 mm) of women with and without ovarian stimulation. The study included women with regular menstrual cycles who were proven to be fertile (n = 20) and PCOS women with follicular arrest who were candidates for ovarian drilling (n = 17), as well as other patients requiring ovarian stimulation, i.e. control women undergoing IVF for male factor infertility (n = 12) and PCOS women undergoing IVF (n = 17). In vitro studies were carried out on granulosa-lutein cells (GCs) obtained from subsets of women undergoing IVF for male factor infertility (n = 6) and PCOS women undergoing IVF (n = 6). GCs were maintained in culture for up to 6 days. PARTICIPANTS/MATERIALS, SETTING, METHODS: Intrafollicular estradiol, estrone and EMs concentrations were determined by high performance liquid chromatography-mass spectrometry. Testosterone in serum was measured by RIA, and LH, FSH and sex hormone-binding globulin in serum were measured with IRMA kits. AMH was determined in serum and FF by enzyme linked immunosorbant assay (ELISA). VEGF levels were measured in FF and conditioned medium by ELISA. Conditioned medium were obtained from cultured GCs. The angiogenic potential was assessed by in vitro angiogenic assays. MAIN RESULTS AND THE ROLE OF CHANCE: Pro-angiogenic EMs (4-OHE1, 16-kE2 and 2-OHE2) and VEGF were lower in FF of antral follicles of PCOS women with follicular arrest compared those of fertile women with ovulatory cycles (P < 0.05). In contrast, higher concentrations of AMH were found in FF of antral follicles from PCOS women with follicular arrest compared to those of fertile women with ovulatory cycles (P < 0.05). Exogenous gonadotropins used in IVF increased pro-angiogenic EMs and VEGF production in PCOS women, reaching similar profiles compared to control women receiving gonadotropins in their IVF treatment for male factor infertility. The pro-angiogenic EM 2-OHE2 increased the angiogenic potential and VEGF levels of GCs from PCOS women compared to the basal condition (P < 0.05). These findings suggest that there is a role for pro-angiogenic EMs in the control of follicular VEGF production. LIMITATIONS, REASONS FOR CAUTION: The limitations include the possibility that in vitro analysis of GCs might not reflect the in vivo mechanisms involved in the pro-angiogenic action of 2-OHE2 since GCs obtained at the time of oocyte retrieval belong to a very early stage of the luteal phase and might not be representative of GCs during follicular growth. Therefore, our findings do not conclusively rule out the possibility that other in vivo mechanisms also account for defective angiogenesis observed in PCOS. WIDER IMPLICATIONS OF THE FINDINGS: The present study highlights the significance of EMs, angiogenic factors and AMH and their interaction in the pathophysiology of follicular development in PCOS. This study provides new insights into the role of pro-angiogenic factors in follicular arrest in PCOS. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by CONICYT/FONDECYT 1140693 and NIH grant R01HD083323. All authors declare no conflict of interest. TRIAL REGISTRATION NUMBER: N/A.

Anti-Müllerian hormone in type 2 and gestational diabetes during the second half of pregnancy: relationship with sexual steroid levels and metabolic parameters.

Hyperandrogenemia and hyperinsulinemia are observed in women with diabetes during pregnancy. The effect of diabetes on anti-Müllerian hormone (AMH) levels during pregnancy is unclear. The aim of this study was to determine the AMH levels in women with type 2 diabetes (T2D) and gestational diabetes (GD) compared to healthy (C) pregnant women during the second half of gestation. A prospective study of 69 pregnant women with T2D (N: 21), GD (N: 24) and C (N: 24) were followed up during the second half of pregnancy. Clinical assessments and blood samples were collected at 26.7 (25-27.8); 34 (32-34.9) and 37.5 (37-40) weeks of gestation. AMH, sexual steroids, insulin, homeostatic model assessment of insulin resistance, HbA1c levels were measured. AMH levels were similar between T2D, GD and C (p = .07). A decline of AMH levels during the second half of gestation was observed in the three groups (p < .0001). AMH levels were negatively associated with age (p < .001). A positive association between AMH and testosterone (p < .05) was found in all groups. A progressive decline of AMH levels is observed in diabetic and healthy women during the second half of pregnancy. Testosterone levels are an independent factor that influences AMH levels during pregnancy. However, AMH levels are not affected by the presence of diabetes during gestation.

In-vitro study of gonadotrophin signaling pathways in human granulosa cells in relation to progesterone receptor expression.

In humans, data on gonadotrophin-activated (LH, HCG and FSH) progesterone receptor expression and signalling pathways involved in matrix metalloproteinases (MMPs) expression presumably linked to the follicle rupture, are limited. Our hypothesis is LH, HCG and FSH increase progesterone receptor expression in granulosa cells through different signalling pathways, leading to an increased expression of ADAMTS-1 and MMP3/10, which may mediate follicular rupture through the transcription factor, HIF1A. Human granulosa cells were isolated from follicular aspirates obtained from 22 healthy women participating in our IVF programme for male-factor infertility. Progesterone receptor and HIF1A expression was assessed by immunofluorescence, and PKA-PKC-PI3K- ERK1/2, ADAMTS-1 and MMP3/10 expression by Western blot in pre-ovulatory and in cultured granulosa cells. Results show that HCG, LH and FSH regulate progesterone receptor expression and activate PKA, PKC, PI3K and ERK1/2 signalling pathways in granulosa cells but progesterone receptor expression is only mediated by PKA, PKC and ERK pathways. HCG, FSH and LH regulated MMPs expression through progesterone receptors. Moreover, HCG-progesterone-receptor-dependent HIF1A expression stimulated MMP3/10 expression but not that of ADAMTS-1. These results suggest differential downstream progesterone receptor signalling, as progesterone receptor regulates MMP3/10 expression via HIF1A, which is not involved in ADAMTS-1 expression.

Pregestational type 2 diabetes and gestational diabetes exhibit different sexual steroid profiles during pregnancy.

Higher androgen levels are observed in non-pregnant women with diabetes. Whether this hormonal profile is found during pregnancy is unknown. The aim of this study was to determine the sexual steroids levels in pregnant women with pregestational type 2 (T2D) and gestational diabetes (GD) compared to healthy control (C) pregnant women during the second half of pregnancy. A prospective study of 69 pregnant women with T2D (n = 21), GD (n = 24) and control (C, n = 24) was followed up during the second half of gestation. Clinical assessments and blood samples were collected at 26.7 (25-27.8); 34 (32-34.9) and 37.5 (37-40) weeks of gestation. Androgens, sex hormone-binding globulin (SHBG), estrogens, estradiol/testosterone (E/T) ratio, insulin, glucose, HOMA-IR, were measured. Testosterone, insulin and homeostatic model assessment of insulin resistance (HOMA-IR) levels were higher in T2D compared with C at each sampling point during pregnancy, even after adjusting for BMI and age. Estrogens levels and estradiol/testosterone ratio were lower in T2D and GD compared with C. Hyperandrogenemia, and higher insulin resistance is observed in T2D, but not in GD during pregnancy. Decreased estrogen and E/T ratio found in T2D and GD suggests a diminished aromatase activity during gestation. T2D and GD are associated with specific changes in sexual steroids and insulin resistance levels during pregnancy.

Neuroendocrinology and ovarian aging.

The ovarian aging, a dynamic process that precedes the clinical manifestations of menopause, can be assessed using ovarian reserve biomarkers. It is well-known that reproduction during the later years of reproductive life has known limitations that challenge the success of assisted reproduction. Therefore, a review of the neuroendocrine modifications during this critical period of reproductive life may help to elucidate the ovarian aging process and its impact on reproduction. In this review, we aim to further the discussion of neuroendocrine changes taking place during the ovarian aging process that may impact reproductive function.

Assessment of diagnostic competence of plasmatic androgens on polycystic ovary syndrome based on receiver operator characteristic curves.

OBJECTIVE: This study was designed to assess the diagnostic potency of different androgens in hyperandrogenaemia criterion on polycystic ovary syndrome (PCOS) based on receiver operator characteristic (ROC) curves analysis. METHODS: We evaluated 55 PCOS patients and 27 healthy fertile women (control). Androgen evaluation included bio-available testosterone (BAT) by ammonium sulphate precipitation, Free Testosterone Index (FTI), androstenedione (A), total testosterone and dehydroepiandrosterone sulphate (DHEA-S). RESULTS: The androgen tests with the best diagnostic capacities were FTI and BAT. Although T and A had similar diagnostic potencies, A detected 5% of PCOS patients that could not be recognised by FTI, BAT (%), or T. The association of FTI, BAT (%) and A identified 96.36% of the hyperandrogenaemic patients. DHEA-S showed a wide dispersion of values and therefore poor discriminatory competence. DISCUSSION: This study suggests that routine androgen evaluation in PCOS should include FTI, BAT and A to avoid misdiagnosis. ROC curve analysis of these tests on patients with the complete spectrum of PCOS phenotypes is needed to confirm these results.

Human corpus luteum physiology and the luteal-phase dysfunction associated with ovarian stimulation.

The human corpus luteum is a temporary endocrine gland that develops after ovulation from the ruptured follicle during the luteal phase. It is an important contributor of steroid hormones, particularly progesterone, and is critical for the maintenance of early pregnancy. Luteal-phase dysfunction can result in premature regression of the gland, with a subsequent shift to an infertile cycle. Understanding the mechanism of steroidogenesis during corpus luteum growth and regression is crucial for evaluating the normal physiology and pathophysiology of reproductive cycles. The rate-limiting step in corpus luteum steroidogenesis is the transport of cholesterol to the site of steroid production. Steroidogenic acute regulatory protein is a key player in this process and is positively correlated with progesterone concentrations throughout the early and mid-luteal phase. Changes in the endocrine environment brought on by the gonadotrophins used for ovarian stimulation are thought to underlie the corpus luteum dysfunction associated with IVF cycles. While ovarian hyperstimulation syndrome is associated with human chorionic gonadotrophin (HCG), studies suggest that exogenous progesterone provides necessary luteal support in patients undergoing IVF. The current trend towards simple stimulation protocols and the use of single-embryo transfers provide further opportunity to revisit HCG administration as luteal support.

Molecular modelling predicts that 2-methoxyestradiol disrupts HIF function by binding to the PAS-B domain.

An estradiol metabolite, 2-methoxyestradiol (2ME), has emerged as an important regulator of ovarian physiology. 2ME is recognized as a potent anti-angiogenic agent in clinical trials and laboratory studies. However, little is known about its molecular actions and its endogenous targets. 2ME is produced by human ovarian cells during the normal menstrual cycle, being higher during regression of the corpus luteum, and is postulated to be involved in the anti-angiogenic process that plays out during luteolysis. We utilized cell biology techniques to understand the molecular mechanism of 2ME anti-angiogenic effects on human granulosa luteal cells. The principal effect of 2ME was to alter Hypoxia Inducible Factor 1A (HIF1A) sub-cellular localization. Molecular modelling and multiple bioinformatics tools indicated that 2ME impairs Hypoxia Inducible Factor complex (HIF) nuclear translocation by binding to a buried pocket in the HIF1A Per Arnt Sim (PAS)-B domain. Binding of 2ME to HIF1A protein is predicted to perturb HIF1A-Hypoxia Inducible Factor B (HIFB) interaction, a key step in HIF nuclear translocation, preventing the transcriptional actions of HIF, including Vascular Endotelial Growth Factor (VEGF) gene activation. To our knowledge, 2ME is the first putative HIF endogenous ligand characterized with anti-angiogenic activity. This postulate has important implications for reproduction, because angiogenic processes are critical for ovarian follicular development, ovulation and corpus luteum regression. The present research could contribute to the development of novel pharmacological approaches for controlling HIF activity in human reproductive diseases.

Features of natural and gonadotropin-releasing hormone antagonist-induced corpus luteum regression and effects of in vivo human chorionic gonadotropin.

CONTEXT: The natural process of luteolysis and luteal regression is induced by withdrawal of gonadotropin support. OBJECTIVE: The objectives of this study were: 1) to compare the functional changes and apoptotic features of natural human luteal regression and induced luteal regression; 2) to define the ultrastructural characteristics of the corpus luteum at the time of natural luteal regression and induced luteal regression; and 3) to examine the effect of human chorionic gonadotropin (hCG) on the steroidogenic response and apoptotic markers within the regressing corpus luteum. DESIGN: Twenty-three women with normal menstrual cycles undergoing tubal ligation donated corpus luteum at specific stages in the luteal phase. Some women received a GnRH antagonist prior to collection of corpus luteum, others received an injection of hCG with or without prior treatment with a GnRH antagonist. MAIN OUTCOME MEASURE: Main outcome measures were plasma hormone levels and analysis of excised luteal tissue for markers of apoptosis, histology, and ultrastructure. RESULTS: The progesterone and estradiol levels, corpus luteum DNA, and protein contents in induced luteal regression resembled those of natural luteal regression. hCG treatment raised progesterone and estradiol in both natural luteal regression and induced luteal regression. The increase in apoptosis detected in induced luteal regression by cytochrome c in the cytosol, activated caspase-3, and nuclear DNA fragmentation, was similar to that observed in natural luteal regression. The antiapoptotic protein Bcl-2 was significantly lower during natural luteal regression. The proapoptotic proteins Bax and Bak were at a constant level. Apoptotic and nonapoptotic death of luteal cells was observed in natural luteal regression and induced luteal regression at the ultrastructural level. hCG prevented apoptotic cell death, but not autophagy. CONCLUSION: The low number of apoptotic cells disclosed and the frequent autophagocytic suggest that multiple mechanisms are involved in cell death at luteal regression. hCG restores steroidogenic function and restrains the apoptotic process, but not autophagy.

The significance of estradiol metabolites in human corpus luteum physiology.

The human corpus luteum (CL) is a temporary endocrine gland derived from the ovulated follicle. Its formation and limited lifespan is critical for steroid hormone production required to support menstrual cyclicity, endometrial receptivity for successful implantation, and the maintenance of early pregnancy. Endocrine and paracrine-autocrine molecular mechanisms associated with progesterone production throughout the luteal phase are critical for the development, maintenance, regression, and rescue by hCG which sustains CL function into early pregnancy. However, the signaling systems driving the regression of the primate corpus luteum in non-conception cycles are not well understood. Recently, there has been interest in the functional roles of estradiol metabolites (EMs), mostly in estrogen-producing tissues. The human CL produces a number of EMs, and it has been postulated that the EMs acting via paracrine-autocrine pathways affect angiogenesis or LH-mediated events. The present review describes advances in understanding the role of EMs in the functional lifespan and regression of the human CL in non-conception cycles.

Estrogen metabolites in human corpus luteum physiology: differential effects on angiogenic activity.

OBJECTIVE: To determine tissue concentrations of E2, estrone, P, and estrogens metabolites (EMs) 2-methoxyestradiol, 2-methoxyestrone, 4-hydroxyestrone, and 16-ketoestradiol in corpus luteum (CL) of different ages, and after hCG administration; and to examine the effects of EMs on vascular endothelial growth factor (VEGF) secretion and angiogenic activity released by cultured luteinizing granulosa cells in the presence and absence of hCG. DESIGN: Experimental study. SETTING: University. PATIENT(S): Thirty-two healthy women of reproductive age. INTERVENTION(S): Corpus luteum was collected at the time of minilaparotomy for tubal sterilization, at varying stages of the luteal phase (LP). Late-LP CL was collected 24 hours after IM administration of 10,000 IU hCG. Granulosa cells were isolated from follicular aspirates obtained from healthy women participating in our IVF program for male factor infertility. MAIN OUTCOMES MEASURE(S): Estrogen metabolite concentrations were determined in CL tissue, and VEGF was assessed in conditioned medium. The angiogenic activity was analyzed by bioassay. RESULT(S): Concentrations of EMs with proangiogenic activity (16-ketoestradiol and 4-hydroxyestrone) were higher in early and mid-LP CL vs. late-LP CL. These EMs and hCG increased VEGF production and angiogenic activity. Conversely, late-LP CL had significantly higher levels of 2-methoxyestrone and 2-methoxyestradiol, which have antiangiogenic activity. Administration of hCG reduced the production of these EMs. CONCLUSION(S): Our findings suggest that the EMs are important paracrine modulators of CL function. Administration of hCG increases the production of EMs with proangiogenic activity and reduces the secretion of those EMs with antiangiogenic action, suggesting a novel mechanism by which the late-LP CL is rescued in conception cycles.

Ultrastructural and biochemical evidence for the presence of mature steroidogenic acute regulatory protein (StAR) in the cytoplasm of human luteal cells.

The distribution of the steroidogenic acute regulatory protein (StAR) inside thecal and granulosa-lutein cells of human corpus luteum (CL) was assessed by immunoelectron microscopy. We found greater levels of StAR immunolabeling in steroidogenic cells from early- and mid-than in late luteal phase CL and lower levels in cells from women treated with a GnRH antagonist in the mid-luteal phase. Immunoelectron microscopy revealed significant levels of StAR antigen in the mitochondria and in the cytoplasm of luteal cells. The 30 kDa mature StAR protein was present in both mitochondria and cytosol (post-mitochondrial) fractions from homogenates of CL at different ages, whereas cytochrome c and mitochondrial HSP70 were detected only in the mitochondrial fraction. Therefore, we hypothesized that either appreciable processing of StAR 37 kDa pre-protein occurs outside the mitochondria, or mature StAR protein is selectively released into the cytoplasm after mitochondrial processing. The presence of mature StAR in the cytoplasm is consonant with the notion that StAR acts on the outer mitochondrial membrane to effect sterol import, and that StAR may interact with other cytoplasmic proteins involved in cholesterol metabolism, including hormone sensitive lipase.

The steroidogenic response and corpus luteum expression of the steroidogenic acute regulatory protein after human chorionic gonadotropin administration at different times in the human luteal phase.

This study was designed 1) to assess corpus luteum (CL) steroidogenesis in response to exogenous human chorionic gonadotropin (hCG) at different times during the luteal phase, 2) to examine the effect of hCG on steroidogenic acute regulatory protein (StAR) expression within the CL, 3) to correlate StAR expression and luteal steroidogenic responses to hCG, and 4) to determine whether endogenous LH regulates ovarian steroidogenesis in the early luteal phase. Blood was collected before and after hCG treatment for steroid and hCGbeta determinations. CL were obtained at the time of surgery to assess StAR gene and protein expression. During the early luteal phase various women received the GnRH antagonist for 24-48 h; some of them also received hCG 24 h after the GnRH antagonist. A slight steroidogenic response to hCG was observed in early luteal phase; 17alpha-hydroxyprogesterone, but not progesterone (P4), levels were significantly increased 8 h post-hCG, indicating a differential response by the granulosa and theca-lutein cells. The 1.6- and 4.4-kb StAR transcripts and the 37-kDa preprotein and 30-kDa mature StAR protein did not change post-hCG administration in early luteal phase CL. In contrast, the StAR 4.4- and 1.6-kb transcripts diminished significantly (P < 0.05) after the antagonist treatment. Immunohistochemical staining for StAR protein was weak, particularly in granulosa-lutein cells. Treatment with hCG restored StAR mRNA and protein and plasma P4 levels within 24 h in antagonist-treated women. hCG stimulated the highest plasma concentrations of P4 and estradiol in the midluteal phase, indicating its greatest steroidogenic capacity. Midluteal tissue StAR gene and protein expression increased by 1.6- and 1.4-fold after 24 h of hCG treatment, respectively. Administration of hCG resulted in the greatest increment in plasma P4 (4-fold) and 17alpha-hydroxyprogesterone (3-fold) levels over baseline in the late luteal phase. This was associated with an increase in StAR mRNA (3.5-fold) and protein (1.8-fold). Collectively, these data indicate that 1) the hCG-stimulated steroidogenic response is dependent on the age of the CL; 2) the early luteal phase CL is relatively insensitive to exogenous hCG in the presence of normal pituitary gonadotropin support, but becomes responsive when the latter is withdrawn; 3) the hCG-stimulated steroidogenic response in the mid- and late luteal phase is correlated with increased StAR mRNA and protein abundance; and 4) there are differential responses of small and large luteal cells to hCG stimulation that depend upon the age of the CL.

Control of human luteal steroidogenesis.

The human corpus luteum (CL) undergoes a dynamic cycle of differentiation, steroid hormone production and regression during the course of non-fertile cycles. In humans and other primates, luteal steroidogenesis is absolutely dependent on pituitary-derived LH. However, changes in LH and LH receptor expression do not explain the marked decline in progesterone production at the end of the luteal phase. Changes in the level of the steroidogenic acute regulatory protein (StAR), a gene whose expression is controlled by LH most likely account for the cyclic pattern of progesterone production. During the mid-to-late luteal phase of a fertile cycle, chorionic gonadotropin (hCG) rescues the CL, overcoming the actions of the factors inducing luteolysis. Although the agents causing regression of the CL in a non-fertile cycle are not yet known, intra-luteal growth factors and cytokines that modify the action of LH probably contribute to the reduction of StAR expression and the subsequent fall in progesterone production.

Molecular regulation of progesterone secretion by the human corpus luteum throughout the menstrual cycle.

The present study examines the expression of the steroidogenic acute regulatory protein (StAR) within the human corpus luteum (CL) in conjunction with other molecules that regulate the apoptotic process of the CL. Our results indicate that the primary 1.6 kb StAR transcript occurs in greater abundance in early and mid-luteal phase compared with late luteal phase CL. Mature StAR protein (30 kDa) was present in lower amounts within late CL compared with early and mid-luteal phase. The pre-protein (37 kDa), which has been considered the active isoform to favor cholesterol translocation and subsequently steroid hormone synthesis, was also detected in lower amount in late CL. Several molecules, including pro-inflammatory cytokines, reactive oxygen species, steroids and inducible nitric oxide synthase (iNOS), have been linked as pro-apoptotic regulatory agents. Moreover, many of these molecules diminish progesterone synthesis in human cultured luteal cells. Interestingly, these molecules preferentially decrease progesterone biosynthesis in mid and late luteal cells in culture. These data suggest that the inhibitory effect of these molecules, as well as the amount of apoptotic cells in the CL are age dependent. The number of luteal apoptotic cells, as well as luteal cells stained positive for iNOS, increased from early to late CL. To examine the effects of hCG on StAR expression and apoptosis, we used two models-(1) in vivo hCG administration during the late luteal phase; and (2) in vitro incubation of explants of late CL with hCG. hCG increased both the level of StAR expression and the level of anti-apoptotic protein Bcl-2 within the late CL. We conclude that mRNA and protein expression of StAR and bcl-2 are important target elements for hCG during the CL rescue.

Complement C3 and decay-accelerating factor expression levels are modulated by human chorionic gonadotropin in endometrial compartments during the implantation window.

The control of complement activation in the embryo-maternal environment has been demonstrated to be critical for embryo survival. Complement proteins are expressed in the human endometrium; however, the modulation of this expression by embryo signals has not been explored. To assess the expression of complement proteins in response to human chorionic gonadotropin (hCG), we designed an experimental study using in vivo and in vitro models. Twelve fertile women were treated with hCG or left untreated during the mid-luteal phase, and an endometrial biopsy was performed 24 hours later. The localizations of C3, membrane cofactor protein (MCP; CD46), decay-accelerating factor (DAF; CD55), and protectin (CD59) were assessed by immunohistochemistry, and the messenger RNA (mRNA) levels of these proteins were quantified by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) in cells harvested from endometrial compartments using laser capture microdissection. Endometrial explants were cultured with or without hCG for 24 hours, and the C3 and DAF protein levels were measured by Western blotting. Elevated C3 mRNA levels in stromal cells and elevated DAF levels in epithelial luminal cells were detected after hCG treatment. In the endometrial explant model, the progesterone receptor antagonist RU486 inhibited the increases in the levels of C3 and DAF in response to hCG. The findings of this study indicate that hCG plays a role in embryo-endometrium communication and affects the expression of complement proteins in endometrial compartments during the implantation window.

2-Methoxyestradiol in the human corpus luteum throughout the luteal phase and its influence on lutein cell steroidogenesis and angiogenic activity.

OBJECTIVE: To quantitate 2-methoxyestradiol (2-ME) in human corpus luteum (CL) of different ages and to determine the expression of cytochrome-P450-1A1 (CYP1A1) and catechol-O-methyl transferase (COMT) in CL and the action of 2-ME on P, vascular endothelial growth factor (VEGF) secretion, and luteal angiogenesis. DESIGN: Experimental study. SETTING: University division of reproductive endocrinology. PATIENT(S): Twenty-four women of reproductive age. INTERVENTION(S): CL was collected from 15 women during the minilaparotomy for tubal sterilization. Granulosa lutein cells were harvested 36 hours after hCG administration in patients undergoing IVF. MAIN OUTCOMES MEASURE(S): Levels of 2-ME were determined by high-performance liquid chromatography in CL. CYP1A1 and COMT were assessed by immunohistochemistry and Western blot. P and VEGF were measured by radioimmunoassay and ELISA. The angiogenic potential was analyzed using EA.hy926 cells. RESULT(S): Plasma levels of E2 decreased in the late luteal phase in association with an increase in luteal tissue of 2-ME concentrations. Concomitantly, there was a significant reduction of angiogenic activity in late CL. There was no significant variation in CYP1A1 and COMT expression in all CL. In physiological doses, 2-ME inhibited basal VEGF by granulosa lutein cells and diminished the angiogenic activity in conditioned media but did not prevent P and VEGF production stimulated by hCG. CONCLUSION(S): These data suggest the participation of 2-ME in physiological luteolysis by reducing angiogenesis. However, 2-ME did not prevent in vitro hCG stimulation of P biosynthesis, providing a mechanism for CL rescue in the cycle of conception.

Transient expression of progesterone receptor and cathepsin-l in human granulosa cells during the periovulatory period.

OBJECTIVE: To study in vivo the progesterone receptor (PR) expression levels in human granulosa cells (GCs) during the periovulatory period and the affect of the protein kinase A (PKA) pathway on PR expression and cathepsin-L expression-activation. DESIGN: Experimental study. SETTING: University research unit. PATIENT(S): Twenty-five women of reproductive age. INTERVENTION(S): Follicular fluid and GCs obtained from spontaneous cycles before and during the normal luteinizing hormone surge, and samples obtained 36 hours after human chorionic gonadotropin (hCG) administration in patients undergoing in vitro fertilization. MAIN OUTCOME MEASURE(S): To determine PR, cathepsin-L messenger RNA (mRNA) analysis via real-time polymerase chain reaction, and protein of PR, cathepsin-L, and PKA in human GCs. RESULT(S): The Western blot analysis revealed that bands of PR (isoform A) were the most abundant and that mRNA (PR-A and PR-B) have a temporal pattern of expression throughout the periovulatory period. The protein levels of PR and cathepsin-L were up-regulated by hCG. The abundance of PR was diminished in the presence of PKA inhibitor, and cathepsin-L with PR receptor antagonist. CONCLUSION(S): The transient expression of PR in human GCs of the preovulatory follicle suggests that PR and its ligand play a role in the activation of cathepsin-L, which is presumably involved in the degradation of the follicular extracellular matrix during human ovulation.

Physiologic activation of nuclear factor kappa-B in the endometrium during the menstrual cycle is altered in endometriosis patients.

OBJECTIVE: To evaluate nuclear factor kappaB (NF-κB) activation and NF-κB-p65 subunit activation, immunolocalization, and expression in the endometrium of healthy women and endometriosis patients throughout the menstrual cycle. DESIGN: Prospective observational study. SETTING: Affiliated hospital and university research laboratory. PATIENT(S): Twenty-four healthy women and 24 endometriosis patients. INTERVENTION(S): Menstrual, proliferative, and secretory endometrial biopsies. MAIN OUTCOME MEASURE(S): Assessment of NF-κB and p65 activation by protein-DNA binding assays and p65 localization and expression by immunohistochemistry. RESULT(S): Total NF-κB-DNA binding was constitutive and variable in human endometrium accross the menstrual cycle. Healthy women (physiologic conditions) showed higher p65-DNA binding in proliferative than in menstrual and secretory endometrium. Conversely, in endometriosis patients, p65-DNA binding was higher in proliferative and secretory endometrium than in menstrual endometrium. Endometrial epithelial cells showed higher p65 expression level score than endometrial stromal cells. CONCLUSION(S): NF-κB activity is constitutive, physiologic, and variable in human endometrium. The physiologic cyclic p65 activation pattern was altered in endometriosis patients, showing no cyclic variation between the proliferative and secretory phase of the menstrual cycle. The absence of decreased p65 activity in secretory endometrium from endometriosis patients is concurrent with progesterone resistance and could participate in endometrial biologic alterations during the implantation window in endometriosis patients.

A single midcycle dose of levonorgestrel similar to emergency contraceptive does not alter the expression of the L-selectin ligand or molecular markers of endometrial receptivity.

OBJECTIVE: To examine the effects of a single-dose of 1.5 mg of levonorgestrel (commonly used as emergency contraceptive) on endometrial receptivity biomarkers through the oral or vaginal route. DESIGN: Prospective randomized single-blinded trial. SETTING: Affiliated Hospital and University Research Center. PATIENT(S): Fertile normal women previously sterilized by tubal ligation. INTERVENTION(S): Levonorgestrel (1.5 mg) was administered on the day of LH surge either orally (n = 14) or vaginally (n = 13). MAIN OUTCOME MEASURE(S): Molecular assessment of endometrial progesterone receptors, L-selectin ligand, glicodelin-A and αvß3 integrin by Immunohistochemistry and reverse transcriptase-polymerase chain reaction. RESULT(S): Plasma progesterone concentration and endometrial dating were not different. The pattern of progesterone receptors and glycodelin-A expression was not affected during the early and midsecretory phase. Some endometrial biopsies from the group in which levonorgetrel was orally administered showed areas of glandular atrophy and stromal decidualization. However, the expression of the progesterone receptor, L-selectin ligand, αvß3 integrin, and glycodelin-A were not different between the groups. CONCLUSION(S): Levonorgestrel, given as emergency contraceptive on the day of LH surge, does not disrupt either ovulation or progesterone production by the corpus luteum. The contraceptive mechanism of levonorgestrel at the time of LH surge does not include changes in the progesterone receptors or the endometrial receptivity biomarkers.