Endometrial differentiation in the peri-implantation phase of women with recurrent miscarriage: a morphological and immunohistochemical study

YAP1 regulates endometrial receptivity by promoting the plasma membrane transformation and proliferation of bovine endometrial epithelial cells

Plasma membrane transformation (PMT) during early pregnancy (EP) is a widely observed phenomenon across species, but its role in cows remains understudied. Yes1-associated transcriptional regulator (YAP1) plays a vital role in human embryo implantation and uterine development. However, its relationship with PMT in bovine endometrium remains unclear. This study aims to explore the potential influence of YAP1 on PMT and the proliferation of endometrial epithelial cells. We observed PMT-related changes in the endometrium of cows during EP, characterized by reduced morphometry scores and increased fully developed pinopodes. The epithelial marker cadherin-1 (CDH1, also known as E-cadherin) expression decreased, while the mesenchymal marker vimentin (VIM) expression increased. Additionally, YAP1 expression was up-regulated and activated in the endometrial epithelium during EP. Interferon-tau (IFNT) potentially promoted PMT-related changes and activated YAP1. The knockdown of YAP1 diminished the effect of IFNT on PMT. At the same time, overexpression of YAP1 might enhance PMT-related changes and promote the proliferation, migration, and invasion ability of bovine endometrial epithelial cells (bEECs). Our findings suggest that YAP1 is activated during EP and may regulate endometrial receptivity by promoting PMT and cell proliferation.

The expression and role of glycans at the feto-maternal interface in humans

During pregnancy, both the maternal endometrium and the blastocyst have highly glycosylated proteins with glycosylations controlled in a specific manner. Carbohydrates play a fundamental role in cell-cell and cell-matrix recognition and are involved in defining the structure and integrity of tissues. The uterus' secretions, which are rich in glycoproteins and glycogen and the presence of a functional glycocalyx on the uterine epithelium, establish a favourable milieu, which is essential for the correct implantation and subsequent development of the blastocyst. Likewise, carbohydrate residues such as fucose and sialic acid present at the placental level are determinant in creating an immuno-environment, which supports the mother's tolerance towards the fetal antigens. In this review, we explore the literature concerning the role of important glycan-epitopes at the feto-maternal interface in the human species. Moreover, we also show some unpublished interesting results on changes of glycan residues in human placenta tissues from the first trimester of pregnancy.

Integrins expressed on the surface of human endometrial stromal cells derived from a female patient experiencing spontaneous abortion

Here, as a basic study in revealing the correlation between extracellular matrix components and spontaneous abortion, we defined the types of integrins expressed on the surface of endometrial stromal (ES) cells retrieved from the uterus of a patient experiencing spontaneous abortion. For these, the types of integrin subunits in the ES cells retrieved from a woman with spontaneous abortion were identified at the transcriptional and translational levels, and functional assay was conducted for confirming the combinations of integrin α and β subunits. Among the genes encoding 25 integrin subunits, significantly high transcription was seen in integrins α₁, α₂, α₃, α₄, α₅, α_V, β₁, β₃, and β₅. Translation of integrins α₁, α₃, α₅, α_V, and β₁ on the cell surface was detected in almost all ES cells, whereas integrins α₂, α₄, β₃, and β₄ were expressed translationally only in some ES cells. Subsequently, ES cells showed significantly increased adhesion to collagen I, laminin, fibronectin, and vitronectin, and functional blocking of integrin α₁, α₃, α₅, and α_V significantly inhibited adhesion to these molecules. These results demonstrated that active heterodimers composed of integrins α₁β₁, α₃β₁, α₅β₁, and α_Vβ₁ were co-localized on the surface of ES cells derived from a patient experiencing spontaneous abortion.

Dysregulated uterine natural killer cells and vascular remodeling in women with recurrent pregnancy losses

PROBLEM

Angiogenesis and vascular remodeling in secretory endometrium represent one of the crucial steps in pregnancy establishment, for which uterine NK (uNK) cells have an important role. Impairment of these steps may proceed to implantation and instigate initial pathology of recurrent pregnancy losses (RPL). In this study, we aim to investigate vascular development and density of uNK cells in secretory endometrium of women with RPL.

METHODS OF STUDY

Mid-secretory phase endometrial tissues from women with RPL (n = 15) and fertile controls (n = 7) were investigated. CD56⁺ and CD16⁺ uNK cells, CD31⁺ vascular endothelial cells and smooth muscle myosin (SMM)⁺ . Vascular smooth muscle cells (VSMC) expressing SMM were investigated using immunohistochemistry and western blot. High-throughput quantitative real-time polymerase chain reaction (qRT-PCR) was used as well.

RESULTS

CD56⁺ uNK number was significantly higher in women with RPL compared to controls (P < 0.0001). uNK cell density by immunohistochemistry was positively correlated with CD56 mRNA expression by qRT-PCR (r²  = 0.43, P = 0.0137). The number of blood vessels represented by the expression of either CD31 or SMM was higher in women with RPL as compared to controls (P < 0.05 and P < 0.0001, respectively), and correlated with the number of uNK cell (r²  = 0.18, P < 0.04, and r²  = 0.65, P < 0.0001, respectively). The wall thickness of spiral arteries was significantly higher in women with RPL as compared with that of controls (P = 0.0027).

CONCLUSION

Increased uNK cells in mid-secretory endometrium are associated with increased vascularization and defective vascular transformation of spiral arteries in women with RPL.

Personhood status of the human zygote, embryo, fetus

The fields of biology, medicine, and embryology have described the developmental milestones of humans throughout gestation in great detail. It is less clear as to when humans are recognized as people, persons, or beings with rights that are protected by legislation. The practice of law is irrevocably intertwined with that of ethical conduct; and the time at which a human life is considered a person has implications that extend to health care, legislation on abortion, and autonomy of individuals. This article reviews the economical position that fertilization is the moment that personhood of the conceptus begins. Alternate positions proposing that personhood begins at other possible times after fertilization are presented and contrasted to the economical hypothesis. Summary: This article is an original work critically analyzing the various arguments for human personhood at fertilization and thereafter. The various positions on human personhood are compared and contrasted herein. The time of the human lifespan at which personhood is conferred has important implications for health care, legislation, and personal autonomy.

Role of Mucin 1 and Glycodelin A in recurrent implantation failure

OBJECTIVE

To evaluate and compare the levels of Mucin 1 (MUC-1) and Glycodelin A (GdA) in precisely timed endometrial biopsies and blood samples taken from women with recurrent implantation failure, and women with proven fertility, in a control group.

DESIGN

Molecular studies in human blood and tissue.

SETTING

University hospital.

PATIENT(S)

Women with recurrent implantation failure and women with proven fertility.

INTERVENTION(S)

Primary endometrial cells and blood samples during the implantation "window" (between day 7 and day 9 after the surge in luteinizing hormone).

MAIN OUTCOME MEASURE(S)

Expression of MUC-1 and GdA in the human endometrium and in blood during the implantation window were analyzed by enzyme-linked immunosorbent assay. Additionally, MUC-1 and GdA levels in tissue were analyzed by western blot during the same period.

RESULT(S)

Both blood and tissue measurements of MUC-1 and GdA were significantly lower in women with recurrent implantation failure than in fertile women during the implantation window. In addition, we found a highly significant correlation between blood vs. tissue measurements of both MUC-1 and GdA.

CONCLUSION(S)

The present study reveals that blood and tissue levels of MUC-1 and GdA are much lower in women with RIF, compared with those in fertile women. Receptivity can be evaluated with noninvasive blood sampling, rather than more-invasive endometrium sampling, as the blood and tissue measurements of MUC-1 and GdA are correlated.

Endometrial beta3 integrin profile reflects endometrial receptivity defects in women with unexplained recurrent pregnancy loss

BACKGROUND

The pathophysiology of recurrent pregnancy loss (RPL) is still unknown in 50% of the cases. Herein we measure the expression of beta3 integrin subunit, a well-known implantation marker, in women with or without RPL and correlate it with the histological dating of the endometrial tissue.

METHODS

LH-timed endometrial biopsies were obtained from cases (RPL; n = 21, age 33.9+/-4.7) and healthy controls (n = 29; age 29.8+/-4.1) during the mid-secretory phase (post ovulatory day: 8 to 10). Endometrial samples were timed histologically according to Noyes' criteria and underwent immunohistochemical staining for beta3 integrin expression. For statistical analysis the semi-quantitative HSCORE was assessed. Type I (beta3 negative in an out-of-phase endometrium) and Type II defect (beta3 negative in an in-phase endometrium) were also analysed. Statistical analysis was done with Student t-test, Mann Whitney U test, ANCOVA and chi square for trend. Significance was set as P < 0.05.

RESULTS

The mean (SD) age in controls was lower compared to cases [(29.8 (4.1) vs. 33.9 (4.7) - P = 0.001; Student t-test)]. The median (range) expression of beta3 integrin in controls and cases was 1.94 (0 to 3.5) vs. 0.82 (0 to 3.6), respectively (P = 0.001; Mann Whitney U test). Significance was still significant after adjusting for age (P = 0.03;ANCOVA). The normal positive staining > =0.7 of beta3 integrin subunit and in-phase endometrium was seen in 24 out of 29 (82.8%) controls, but in only 6 out of 21 (28.6%) of cases with RPL; Type I and II defects were seen in 10.3 and 6.9% of controls, while present in 52.4 and 19.1% of cases, respectively (P = 0.0005; chi-square).

CONCLUSIONS

Women with unexplained RPL had significantly reduced integrin expression compared to controls. Our findings underline the need for further molecular analysis of endometrial tissue in affected women.

Fundamental role of folliculo-luteal function in recurrent miscarriage

PURPOSE

To re-evaluate the role of folliculo-luteal function (FLF) in recurrent miscarriage (RM) on the basis of new hormonal diagnostic criteria.

METHODS

A prospective, randomized, single-blinded, placebo-controlled study was carried out at 110 apparently healthy patients with three or more miscarriages not related to any presumable predisposing factors of RM were investigated. In the treatment group FLF was normalized preconceptionally. Women in the control group received placebo. FLF was regarded as physiological when the mean of three progesterone (P) values measured every second day between the 4th and 9th day after ovulation or before menstruation was 21.0 ± 2.0 ng/ml.

RESULTS

A significant difference (p < 0.001) was found between the physiological and placebo groups in the occurrence of live births: 93 versus 56 %, pregnancy losses: 7 versus 44 %; premature delivery per births: 10 versus 57 %. Luteal mean P and estradiol values were significantly (p < 0.001) different in cases of spontaneous abortions and premature and mature deliveries, respectively (P: 14.6 ± 2.2, 20.2 ± 2.7, 27.6 ± 3.9 ng/ml). A strong and significant correlation (p < 0.001) was found between luteal mean P values and the duration of pregnancy (r = 0.85), as well as between the P means measured in the luteal phase and different parameters of the newborns: weight (r = 0.89), weight percentile (0.86) and length (0.73). Retrospective analysis of our data suggests that a luteal P mean value of 29.3 ± 2.9 ng/ml characterising patients with singular, mature, eutroph newborns seems to be the most favorable P value for successful reproduction in RM.

CONCLUSION

Determining the oocyte quality and placentation, FLF quantitatively determines the outcome of pregnancy: its duration and different characteristics of the newborns in RM.

Pinopodes, leukemia inhibitory factor, integrin-β3, and mucin-1 expression in the peri-implantation endometrium of women with unexplained recurrent pregnancy loss

OBJECTIVE

To compare pinopode morphology and coverage, and expression of leukemia inhibitory factor (LIF), integrin-β3, and mucin-1 (MUC1) in the peri-implantation endometrium of women with unexplained recurrent pregnancy loss (RPL) versus normal fertile women.

DESIGN

Exploratory clinical study.

SETTING

University-affiliated assisted reproductive center.

PATIENT(S)

Women undergoing assisted reproduction at centers of reproductive medicine in two university teaching hospitals.

INTERVENTION(S)

Endometrial biopsy samples were obtained from women with RPL (test group, n = 30) and normal fertile women (control group, n = 26) 7 days after the day of luteinizing hormone peak. Pinopode morphology and coverage were assessed by use of scanning electron microscopy. Expression of LIF, integrin β3, and MUC1 were evaluated by immunohistochemical staining.

MAIN OUTCOME MEASURE(S)

Pinopode morphology and coverage, and the expression of LIF, integrin-β3, and MUC1 in both groups.

RESULT(S)

Pinopode morphology and coverage, and the expression of LIF and integrin-β3 showed no statistically significant differences between the two groups. The expression of MUC1 was statistically significantly reduced in the glandular epithelial cells and endometrial lumen of the RPL group compared with controls.

CONCLUSION(S)

The morphology and the coverage of pinopodes and expression of LIF and integrin-β3 did not change, but MUC1 expression was statistically significantly reduced in women with RPL compared with normal women.

Molecular aspects of implantation failure

Despite expanding global experience with advanced reproductive technologies, the majority of IVF attempts do not result in a successful pregnancy, foremost as a result of implantation failure. The process of embryo implantation, a remarkably dynamic and precisely controlled molecular and cellular event, appears inefficient in humans and is poorly understood. However, insights gained from clinical implantation failure, early pregnancy loss, and emerging techologies that enable molecular interrogation of endometrial-embryo interactions are unravelling this major limiting step in human reproduction. We review current molecular concepts thought to underlie implantation failure, consider the contribution of embryonic and endometrial factors, and discuss the clinical value of putative markers of impaired endometrial receptivity. Finally we highlight the nature of the dialogue between the maternal endometrium and the implanting embryo and discuss the concept of natural embryo selection. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.

The molecular basis of recurrent pregnancy loss: impaired natural embryo selection

Recurrent pregnancy loss (RPL) is a common and distressing disorder. Chromosomal errors in the embryo are the single most common cause, whereas uterine factors are invariably invoked to explain non-chromosomal miscarriages. These uterine factors are, however, poorly defined. The ability of a conceptus to implant in the endometrium is normally restricted to a few days in the menstrual cycle. A limited 'window of implantation' ensures coordinated embryonic and endometrial development, thereby minimizing the risk of late implantation of compromised embryos. In this paper, we review emerging evidence, indicating that RPL is associated with impaired differentiation of endometrial stromal cells into specialized decidual cells. From a functional perspective, this differentiation process, termed decidualization, is not only critical for placental development but also signals the end of the implantation window and bestows on the endometrium the ability to recognize, respond to and eliminate implanting compromised embryos. Thus, we propose that spontaneous decidualization of the human endometrium, which inevitably causes menstrual shedding in the absence of a viable conceptus, serves as functional 'window for natural embryo selection'. Conversely, impaired decidualization predisposes to late implantation, negates embryo quality control and causes early placental failure, regardless of the embryonic karyotype. This pathological pathway also explains the common observation that many RPL patients seem exceptionally fertile, often conceiving within one or two cycles. Thus, as the clinical correlate of inappropriate uterine receptivity, 'superfertility' should be considered as a genuine reproductive disorder that requires targeted intervention.

Different types of recurrent miscarriage are associated with varying patterns of adhesion molecule expression in endometrium

This study investigated the hypothesis that different types of recurrent miscarriage history are associated with different markers of endometrial receptivity. A secondary objective was to compare the distribution in endometrial epithelium of a group of cell surface components with roles in cell adhesion. Of 54 women who had an implantation window endometrial biopsy, 17 had idiopathic recurrent fetal loss, 17 had idiopathic recurrent loss of empty gestation sacs, 10 had recurrent implantation failure and 10 had two or more normal pregnancies. Immunohistochemistry and HSCORE was used with frozen sections for integrins (alpha1beta1, alpha4beta1, alpha(v)beta3), and MUC1 (BC2) and paraffin sections for osteopontin and MUC1 (BC3). Epithelial beta1 integrins were located primarily in the basolateral membrane compartment. Consistently greater expression of alpha4beta1, alpha1beta1 and alpha(v)beta3 was seen in the luminal epithelium and greater expression of alpha4beta1 and alpha1beta1 in the glandular epithelium of women with recurrent fetal loss when compared with those with recurrent loss of empty gestation sacs. There were no significant differences in the expression of osteopontin or MUC1 between groups. Different endometrial integrin distribution was found in women suffering different types of recurrent pregnancy loss. It is postulated that impairment of the implantation barrier contributes to recurrent fetal loss.

Could the Defects in the Endometrial Extracellular Matrix During the Implantation Be a Cause for Impaired fertility?

PROBLEM

Assessment of concentration of the metalloproteinase 9 (MMP9), tissue inhibitor of metalloproteinases 1 (TIMP1), urokinase plasminogen activator (uPA) and its receptor (uPAR) and leukaemia inhibitory factor (LIF) in the uterine fluid in women with idiopathic infertility and unknown cause for recurrent miscarriage.

METHOD OF STUDY

Uterine fluid obtained from patients with idiopathic infertility (n = 13), patients with unknown cause of recurrent miscarriages (n = 16) and healthy fertile women (n = 14). The assessment of MMP9, TIMP1, uPA, uPAR and LIF were performed with enzyme-linked immunosorbent assay.

RESULTS

Statistically lower expression of MMP9 and TIMP1 in uterine fluid during implantation window in women with infertility and recurrent miscarriage of unknown cause.

CONCLUSION

Changed turnover of the extracellular matrix might be a cause of improper endometrial transition and in effect cause faulty implantation.

Endometrial receptivity markers, the journey to successful embryo implantation

Human embryo implantation is a three-stage process (apposition, adhesion and invasion) involving synchronized crosstalk between a receptive endometrium and a functional blastocyst. This ovarian steroid-dependent phenomenon can only take place during the window of implantation, a self-limited period of endometrial receptivity spanning between days 20 and 24 of the menstrual cycle. Implantation involves a complex sequence of signalling events, consisting in the acquisition of adhesion ligands together with the loss of inhibitory components, which are crucial to the establishment of pregnancy. Histological evaluation, now considered to add little clinically significant information, should be replaced by functional assessment of endometrial receptivity. A large number of molecular mediators have been identified to date, including adhesion molecules, cytokines, growth factors, lipids and others. Thus, endometrial biopsy samples can be used to identify molecules associated with uterine receptivity to obtain a better insight into human implantation. In addition, development of functional in vitro systems to study embryo-uterine interactions will lead to better definition of the interactions existing between the molecules involved in this process. The purpose of this review was not only to describe the different players of the implantation process but also to try to portray the relationship between these factors and their timing in the process of uterine receptivity.

The endocrinological basis of recurrent miscarriages

PURPOSE OF REVIEW

This review discusses the endocrinological aspects of recurrent miscarriage based on the literature from January 2004 to January 2005, elaborating on the advances in the field and their impact on diagnosis and management.

RECENT FINDINGS

Endometrial luteal phase defect is associated with recurrent miscarriage. Fifty years have passed since the diagnostic criteria for dating the endometrial biopsy was established by Noyes et al. This has been the gold standard and last year its accuracy and clinical utility were critically analysed. A Cochrane review has shown a small but statistically significant difference in the live birth rate in the subgroup of women in which progestogen was used to prevent recurrent miscarriage. Endocannabinoids and fatty acid amide hydrolase have been found to have a potential role in signalling for implantation and maintenance of pregnancy.

SUMMARY

Abnormal secretory endometrial changes may adversely affect the early pregnancy outcome. Other dating techniques using biochemical and molecular markers of endometrial function may prove useful in predicting outcome. Use of progestogens with or without estrogens for prevention of recurrent miscarriage needs to be investigated further in larger randomized controlled trials. The role of endocannabinoids and agents modulating their receptors are potentially very exciting areas to be explored further.

Evaluation of steroid receptors, coregulators, and molecules associated with uterine receptivity in secretory endometria from untreated women with polycystic ovary syndrome

OBJECTIVE

To evaluate gene and protein expression of steroid receptors, nuclear receptor coregulators, and uterine receptivity markers in midsecretory phase endometria from untreated women with polycystic ovary syndrome (PCOS).

DESIGN

Case-control study.

SETTING

Hospital research unit.

PATIENT(S)

Eight patients with PCOS and eight fertile women of similar age to those with PCOS.

INTERVENTION(S)

Endometrial samples were obtained from women with PCOS (PCOSE) and normal (NE) women during the midsecretory phase of the menstrual cycle.

MAIN OUTCOME MEASURE(S)

Expression studies (immunohistochemistry, reverse transcription-polymerase chain reaction [RT-PCR] and Western blot).

RESULT(S)

Endometria from PCOS exhibit higher levels of messenger RNA (mRNA) and protein for estrogen receptor alpha and coactivators than NE. Epithelial cells had a greater expression of progesterone receptor in PCOSE, whereas, no differences were observed in gene and protein expression of the nuclear corepressor (NcoR) and the antiadhesion molecule mucin type-1 (MUC-1) between PCOSE and NE. Immunodetection for the coactivator ARA70 was higher in PCOSE than in NE; in contrast, expression of beta3-integrin in epithelia was lower in PCOSE than in control endometria.

CONCLUSION(S)

The higher response to steroid hormones of endometria from untreated PCOS-women induces diminished expression of beta3 integrin, which partially explain implantation failure in PCOS patients.

The expression pattern of MUC1 glycoforms and other biomarkers of endometrial receptivity in fertile and infertile women

Changes in the surface epithelium of the endometrium, characterized in part by alterations in cell-surface molecules, sex steroid receptors and the appearance of pinopodes, coincide with the window of endometrial receptivity in the menstrual cycle. This study was performed to evaluate the usefulness of hematoxylin and eosin staining, scanning and transmission microscopy, and MUC1 glycoform, sex steroid receptor, and interleukin receptor (type 1) expression as biomarkers of endometrial receptivity using carefully characterized clinical fertile and infertile groups of women. Using a combination of immunohistochemistry and scanning electron microscopy (SEM) called scanning immunoelectron microscopy (SIM), we confirmed that MUC1 mucin was not associated with the endometrial pinopodes, which have been linked with embryo adhesion. We also showed that failure of embryo implantation was associated with an abnormal endometrial expression of MUC1 mucin, and retention of nuclear progesterone receptor (PR) particularly in epithelial cells. Hematoxylin and eosin staining, transmission electron microscopy (TEM), SEM in isolation and immunohistochemistry for interleukin receptor were not shown to be useful markers. Progesterone-dependent regulation of MUC1 appears to be an important factor in determining endometrial receptivity.

Characterizing the endometrium in unexplained and tubal factor infertility: A multiparametric investigation

OBJECTIVE

To characterize endometrial development in unexplained and tubal factor infertility.

DESIGN

Prospective study of 20 women with unexplained infertility, 22 with tubal factor infertility, and 21 fertile controls in the midproliferative, periovulatory, and midluteal phases of the menstrual cycle.

SETTING

Reproductive Medicine Department of St. Mary's Hospital, Manchester, United Kingdom.

PATIENT(S)

Women awaiting assisted conception.

INVESTIGATION(S)

Serum hormone assays, transvaginal ultrasound, Doppler, and midluteal endometrial biopsies.

MAIN OUTCOME MEASURE(S)

Serum levels of E2, P, and LH, endometrial ultrasound morphometry, uterine and subendometrial artery Doppler, and endometrial histology and biochemistry.

RESULT(S)

Women with unexplained infertility demonstrated significantly reduced uterine artery flow velocity in all phases, significantly elevated uterine and subendometrial artery impedance in the periovulatory and midluteal phases, and significantly reduced endometrial texture in the midproliferative phase. Women with tubal factor infertility demonstrated significantly reduced uterine artery flow velocity, without a concomitant increase in impedance, and significantly greater expression of endometrial glandular and luminal keratan sulphate.

CONCLUSION(S)

Unexplained infertility is associated with a profound impairment of endometrial perfusion that might be amenable to treatment by perfusion enhancers. Tubal factor infertility is associated with endometrial developmental defects that might be corrected by salpingectomy. Endometrial ultrasound and Doppler studies are likely to become a vital tool in the investigation of infertility.

Trophoblast-uterine interactions at implantation

Implantation of the embryo in the uterus is a critical and complex event and its failure is widely considered an impediment to improved success in assisted reproduction. Depending on whether placentation is invasive or superficial (epitheliochorial), the embryo may interact transiently or undergo a prolonged adhesive interaction with the uterine epithelium. Numerous candidate interactions have been identified, and there is good progress on identifying gene networks required for early placentation. However no molecular mechanisms for the epithelial phase are yet firmly established in any species. It is noteworthy that gene ablation in mice has so far failed to identify obligatory initial molecular events.

Glycodelin: a major lipocalin protein of the reproductive axis with diverse actions in cell recognition and differentiation

Glycodelin is a glycoprotein that belongs to the lipocalin superfamily. Depending on glycosylation, glycodelin appears in various isoforms. In the uterus, glycodelin-A is the major progesterone-regulated glycoprotein secreted into uterine luminal cavity by secretory/decidualized endometrial glands. The other tissues expressing glycodelin include fallopian tubes, ovary, breast, seminal vesicle, bone marrow, and eccrine glands. Glycodelin-A potently and dose-dependently inhibits human sperm-egg binding, whereas differently glycosylated glycodelin-S from seminal plasma has no such effect. Absence of contraceptive glycodelin-A in the uterus during periovulatory midcycle is consistent with an open "fertile window." Glycodelin induced by local or systemic administration of progestogens may potentially reduce the fertilizing capacity of sperm in any phase of the menstrual cycle. Glycodelin also has immunosuppressive activity. Its high concentration at the fetomaternal interface may contribute to protection of the embryonic semiallograft. Besides being an epithelial differentiation marker, glycodelin appears to play a role in glandular morphogenesis, as transfection of glycodelin cDNA into a glycodelin-negative breast cancer cells resulted in formation of gland-like structures, restricted proliferation, and induction of other epithelial markers. These various properties, as well as the chemistry, biology, and clinical aspects of glycodelin, continue to be areas of active investigation reviewed in this communication.

High serum luteinizing hormone and testosterone concentrations do not predict pregnancy outcome in women with recurrent miscarriage

OBJECTIVE

To investigate the relationship between Day 8 serum luteinizing hormone (LH) and testosterone (T) concentrations, and body mass index (BMI) with pregnancy outcome in women with recurrent miscarriage.

DESIGN

Prospective observational study.

SETTING

National recurrent miscarriage clinic.

PATIENT(S)

Three hundred forty-four women (median age 32 years; range 18-44) with a history of recurrent first trimester miscarriage (median 4; 3-14; <12 weeks gestation) who conceived spontaneously and who received no pharmacological treatment during pregnancy were studied. All women were antiphospholipid antibody negative and had a normal peripheral karyotype as did their partners.

INTERVENTION(S)

Outcome of untreated pregnancies.

MAIN OUTCOME MEASURE(S)

Day 8 serum LH and T concentrations and BMI were correlated with pregnancy outcome.

RESULT(S)

One hundred and ninety-two (55.8%) women had a live birth and 152 (44.2%) women miscarried. Polycystic ovarian morphology was diagnosed in 174 women (50.6%). There was no significant relationship between follicular phase LH concentrations and pregnancy outcome. Pregnancy outcome was similar in women with normal and high serum T concentrations. BMI value was not significantly different between women who had a live birth and those who miscarried.

CONCLUSION(S)

The analysis of this large cohort of women with recurrent miscarriage demonstrates that prepregnancy Day 8 serum LH and T concentrations, and BMI do not have a statistically significant relationship with pregnancy outcome.

Endocrinological and endometrial factors in recurrent miscarriage

OBJECTIVE

To investigate the endocrinological and endometrial factors in women with unexplained recurrent miscarriage

DESIGN

Prospective, case study

SETTING

Recurrent miscarriage clinic, Jessop Hospital for Women, Sheffield

PARTICIPANTS

One hundred and forty-four women with unexplained recurrent (> or =3) miscarriages

METHODS

A blood sample was obtained in early follicular phase (day 3-5) to measure follicle stimulating hormone, luteinising hormone, prolactin, androgens and thyroid function; daily blood/urine samples were obtained from mid-follicular phase to measure luteinising hormone until the luteinising hormone surge was identified; endometrial biopsy and a further blood sample for progesterone measurement were obtained in the mid-luteal phase. A transvaginal ultrasonography was performed to evaluate ovarian morphology.

RESULTS

Hypersecretion of luteinising hormone or ultrasonographic features of polycystic ovarian disease was present in 8% and 7.8% of women, respectively. The free androgen index was elevated in 14.6% of subjects. In the mid-luteal phase, low progesterone level was found in 17.4% and delayed endometrial development was noted in 27.1% of women. Although women with recurrent miscarriage women and delayed endometrium had significantly lower progesterone levels than those with normal endometrial development, only 8/24 had mid-luteal progesterone levels below 30 nmol/L. Recurrent miscarriage was not associated with hyperprolactinaemia or abnormal thyroid function test.

CONCLUSIONS

Endocrinological and endometrial abnormalities are present in about a quarter of women with unexplained recurrent miscarriage.

Endocrinology of the peri-implantation period

Current research suggests that the appearance of endometrial integrins and pinopode appearance signal the opening of the receptive phase of the endometrium. These integrins may be activated by the interleukin-1 system (IL-1). IL-1beta, expressed by the blastocyst, induces vascular endothelial growth factor (VEGF) which, in turn, promotes angiogenesis and integrin expression in endometrial cells. The IL-1 system also triggers the expression of gamma interferon (IFN-gamma) from T lymphocytes. Decidual natural killer (NK) lymphocytes interact with invading trophoblast to generate leukaemia inhibitory factor (LIF). LIF induces uPA and gelatinase, enzymes which play a crucial role in trophoblastic invasion. Progesterone is a potent inhibitor of LIF, while oestrogen is a potent inducer. Oestrogen in serum reflects follicular IL-1beta level and correlates with the outcome of embryo transfer after in vitro fertilization (IVF). Progesterone induces nitric oxide (NO) synthesis in the decidua, and NO promotes local vasodilatation and uterine quiescenceMeasurement of placental protein 14 (PP14, glycodelin-A) in serum may be of value as a screening test for implantation potential. However, human chorionic gonadotrophin (hCG) remains the most reliable predictor of successful implantation and pregnancy viability. An ovulation + 14 hCG level < 50 IU/l is often predictive of a non-viable outcome, while an ovulation + 21 hCG of < 200 IU/l always indicates a non-viable pregnancy. hCG secretion by invading trophoblast appears to be negatively modulated by endothelin-1 (ET-1) and prostaglandin F(2alpha)(PGF2alpha), while tissue growth factors and collagenases are positive modulators of hCG expression.ProalphaC, an inhibin pro-monomer, may have some value in monitoring corpus luteum function. Inhibin A, activin A and follistatin all rises throughout pregnancy and peak at 36 weeks of gestation. Relaxin is another ovarian hormone that may have a role in predicting implantation. Relaxin induces placental protein 14 (PP14, glycodelin-A) expression in a receptive endometrium, and measurement of serum PP14 may be of value as a screening test for implantation potential.

Hyperprolactinemic recurrent miscarriage and results of randomized bromocriptine treatment trials

OBJECTIVE

To evaluate hyperprolactinemia in the pathogenesis of recurrent spontaneous abortion.

DESIGN

Randomized trial.

SETTING

Miscarriage clinic, Yokohama City University Hospital, Yokohama, Japan.

PATIENT(S)

From a group of 352 women with recurrent spontaneous abortion, we identified 64 patients with a prolactin disorder that was not associated with any other etiologic abnormalities, including ovarian or endocrinologic disturbances such as luteal phase dysfunction, polycystic ovaries, hypersecretion of LH, galactorrhea, or thyroid hormone disorders.

INTERVENTION(S)

Restoration of prolactin levels with bromocriptine.

MAIN OUTCOME MEASURE(S)

Successful pregnancy (live birth).

RESULT(S)

The percentage of successful pregnancies was higher in the bromocriptine-treated group than in the group that was not treated with bromocriptine (85.7% versus 52.4%, P < .05). Serum prolactin levels during early pregnancy (5-10 weeks of gestation) were significantly higher in patients who miscarried (31.8-55.3 ng/mL) than in patients whose pregnancies were successful (4.6-15.5 ng/mL, P < .01 or P < .05).

CONCLUSION(S)

Appropriate circulating levels of prolactin may play an important role in maintaining early pregnancy, especially in cases of hyperprolactinemic recurrent miscarriage.

Type 2 cadherins in the human endometrium and placenta: their putative roles in human implantation and placentation

PROBLEM

The cadherins are a gene superfamily of calcium-dependent cell adhesion molecules. To date, the role(s) of the cadherins in human implantation remains poorly defined.

METHOD OF STUDY

The spatiotemporal expression of the type 2 cadherins, known as cadherin-11 and cadherin-6, in the endometrium and placenta was examined using the reverse transcriptase-polymerase chain reaction.

RESULTS

Cadherin-6 and cadherin-11 are differentially expressed in the endometrial stroma during the menstrual cycle. The switch between cadherin-6 and cadherin-11 expression in the endometrial stroma occurs during the late secretory phase. Maximum cadherin-11 mRNA levels were observed in the decidua of early pregnancy but were markedly reduced at term. In the placenta, cadherin-11 is expressed in the syncytial trophoblast and extravillous cytotrophoblast columns. However, cadherin-6 seems to be the predominant cadherin subtype present in highly invasive extravillous cytotrophoblasts.

CONCLUSION

Cadherin-11 and cadherin-6 may play a central role in the formation and organization of the human endometrium and placenta.

MUC1 as a cell surface and secretory component of endometrial epithelium: reduced levels in recurrent miscarriage

The mucin MUC1 is a large, highly glycosylated, hormonally regulated product of endometrial glandular and luminal epithelium with both cell surface-associated and secreted isoforms. The abundance of mRNA coding for MUC1 increases about sixfold from the proliferative to the early secretory phase (Hey et al., J. Clin. Endocrinol. Metab. 78:337-342, 1994). Immunohistochemical studies show intracellular deposits accumulating in the early secretory phase followed by the release of MUC1 into gland lumens. The apical surface of luminal epithelium is strongly immunopositive in the early secretory phase. We have used a two site ELISA to measure MUC1 in uterine flushings as a function of time after the luteinising hormone (LH) peak. Low levels of secretory MUC1 are observed before day LH+7, while values on days LH+7-LH+13 are much higher. Using semi-quantitative immunohistochemical methods we have shown that in women suffering recurrent spontaneous miscarriage, mid secretory phase levels of MUC1 core protein and mucin-associated glycans are reduced (Serle et al., Fertil. Steril. 62:989-996, 1994). Similarly, lower core protein levels are observed in uterine flushings after day LH+7 in these women. Reduced epithelial secretory function and a resultant change in uterine fluid composition are features of endometrium from recurrent miscarriage patients.