The effect of antiprogestin (RU 486) and prostaglandin biosynthesis inhibitor (naproxen) on uterine fluid prostaglandin F2 alpha concentrations

Assessment of immune cells in the uterine fluid at the time of the embryo transfer

PROBLEM

Although endometrial receptivity is a key factor in influencing implantation in both naturally conceived and assisted reproductive technology (ART) cycles, very little is known about the endometrium milieu around the time of implantation. Previous studies have demonstrated the presence of several cytokines in the endometrium that affect implantation. However, there is lacking data about the presence of immune cell subtypes within the endometrium and in the uterine cavity at the time of implantation.

METHOD OF STUDY

This study was approved by the Institutional Review Board (# 225589). The study was designed as a prospective observational cohort study between May 2021 and December 2022 at a single academic-based fertility center. All patients underwent at least one In Vitro Fertilization (IVF) cycle and have frozen embryos. Twenty-four participants were recruited for this study which was conducted during the frozen embryo transfer (FET) cycle regardless of the outcome of previous cycles. Two samples were acquired from each subject, denoted as lower and upper. A trial transfer catheter was introduced under ultrasound guidance into the lower uterine segment. Upon removal, the tip was rinsed in IMDM medium containing 10% FBS (lower uterus). A transfer catheter was then loaded with the embryo that was placed in the upper uterus under ultrasound guidance. The tip of the transfer catheter was rinsed in separate aliquot of the above media (upper uterus). After centrifugation, pelleted cells were stained for the following surface markers: CD45, CD3, CD19, CD4, CD8, gamma delta TCR, CD25, CD127, CD66b, CD14, CD16, CD56 and acquired on Sony SP6800 Spectral Analyzer.

RESULTS

Upon staining the pelleted cells, we were able to identify viable leukocytes from samples obtained from both, upper and lower uterus (0.125 × 106 cells ± SD 0.32), (0.123 × 106 cells ± SD 0.12), respectively. Among total viable cells, there was no significant difference in both percent and number of CD45+ cells between the upper and lower uterus (9.88% ± 6.98 SD, 13.67% ± 9.79 SD, p = .198) respectively. However, there was significantly higher expression of CD3+ (p = .006), CD19+ (p = .032) and CD14+ (p = .019) cells in samples collected from upper compared to lower uterus. Within all CD3+ cells, we found that gamma delta T cells (GDT) were the major population of T cells in both upper and lower uterus. In contrast, CD8+ T cells were significantly higher in the lower uterus when compared to the upper uterus (p = .009). There was no statistically significant difference in the expression of CD4+ T cells, T regulatory cells (CD4+CD25+CD127-), NK cells (CD56+), neutrophils (CD66b+) and FcγRIII+ cells (CD16+) between upper and lower uterus.

CONCLUSIONS

We believe the immune milieu at the time of embryo transfer will affect implantation. Understanding the composition of immune cells will guide further research in identifying optimal immune milieus that favor implantation. Comprehensive analysis of endometrium is expected to lead to new diagnostic and therapeutic approaches to improve IVF outcomes.

Ulipristal (UPA) effects on rat ovaries: Unraveling follicle dynamics, ovulation inhibition, and safety implications for prolonged use

Ulipristal (UPA), a selective progesterone receptor modulator, has both agonistic and antagonistic effects on progesterone receptors. UPA suppresses ovulation by inhibiting the luteinizing hormone (LH) surge from the pituitary gland; however, the direct effect of UPA on ovarian tissue remains poorly studied. In the present study, we examined the effects of UPA on the ovaries of rats. Rats were treated for 28 days with UPA, and the effects of UPA on ovarian tissue were examined histologically and the expression of antioxidant genes and cell death markers were also investigated. UPA treatment increased the number of primordial follicles at each treatment group, primordial follicles increased at all dose levels, but the size/magnitude of the effect decreased with the increasing dose. The number of primary and antral follicles tended to increase with increasing UPA levels. Furthermore, the decrease in primary follicle number could be attributed to the exhaustion of follicles, but the examination of proliferation markers, oxidative stress markers, and cell death markers revealed no remarkable toxic effects on ovarian tissues. These results suggest that UPA treatment promotes follicle development at each stage but inhibits ovulation by suppressing the LH surge, resulting in an increase in atretic follicles or unruptured luteinized cysts. These results suggest that UPA may not have both toxic effects on the ovary and a direct local effect on ovarian follicles, but we should be careful about the effects of prolonged UPA treatment in patients with uterine fibroids on their future fecundity.

OUP accepted manuscript

STUDY QUESTION

Is the composition of microRNAs (miRNAs) in uterine fluid (UF) of women with recurrent implantation failure (RIF) different from that of healthy fertile women?

SUMMARY ANSWER

The composition of miRNAs in UF of women with RIF is different from that of healthy fertile women and the dysregulated miRNAs are associated with impaired endometrial receptivity and embryo implantation.

WHAT IS KNOWN ALREADY

It has previously been demonstrated that the miRNAs secreted from endometrial cells into the UF contribute to the achievement of endometrial receptivity. Endometrial miRNAs are dysregulated in women with RIF.

STUDY DESIGN, SIZE, DURATION

In this descriptive laboratory case–control study, miRNA abundancy was compared between UF collected during implantation phase from healthy fertile women (n = 17) and women with RIF (n = 34), which was defined as three failed IVF cycles with high-quality embryos.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Recruitment of study subjects and sampling of UF were performed at two university clinics in Stockholm, Sweden and Tartu, Estonia. The study participants monitored their menstrual cycles using an LH test kit. The UF samples were collected on Day LH + 7–9 by flushing with saline. Samples were processed for small RNA sequencing and mapped for miRNAs. The differential abundance of miRNAs in UF was compared between the two groups using differential expression analysis (DESeq2). Further downstream analyses, including miRNA target gene prediction (miRTarBase), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis (g:Profiler) and external validation using relevant published data, were performed on the dysregulated miRNAs. Two miRNAs were technically validated with quantitative real-time PCR (RT-PCR).

MAIN RESULTS AND THE ROLE OF CHANCE

After processing of the sequencing data, there were 15 samples in the healthy fertile group and 33 samples in the RIF group. We found 61 differentially abundant UF miRNAs (34 upregulated and 27 downregulated) in RIF compared to healthy women with a false discovery rate of <0.05 and a fold change (FC) of ≤−2 or ≥2. When analyzed with published literature, we found that several of the differentially abundant miRNAs are expressed in endometrial epithelial cells and have been reported in endometrial extracellular vesicles and in association with endometrial receptivity and RIF. Their predicted target genes were further expressed both in the trophectodermal cells of blastocyst-stage embryos and endometrial mid-secretory epithelial cells, as assessed by publicly available single-cell transcriptome-sequencing studies. Pathway analysis further revealed that 25 pathways, having key roles in endometrial receptivity and implantation, were significantly enriched. Hsa-miR-486-5p (FC −20.32; P-value = 0.004) and hsa-miR-92b-3p (FC −9.72; P-value = 0.004) were successfully technically validated with RT-PCR.

LARGE SCALE DATA

The data are available in Gene Expression Omnibus (GEO) at https://www.ncbi.nlm.nih.gov/geo/ with GEO accession number: GSE173289.

LIMITATIONS, REASONS FOR CAUTION

This is a descriptive study with a limited number of study participants. Moreover, the identified differentially abundant miRNAs should be validated in a larger study cohort, and the predicted miRNA target genes and enriched pathways in RIF need to be confirmed and further explored in vitro.

WIDER IMPLICATIONS OF THE FINDINGS

RIF is a major challenge in the current IVF setting with no diagnostic markers nor effective treatment options at hand. For the first time, total miRNAs have been extensively mapped in receptive phase UF of both healthy women with proven fertility and women diagnosed with RIF. Our observations shed further light on the molecular mechanisms behind RIF, with possible implications in future biomarker and clinical treatment studies.

STUDY FUNDING/COMPETING INTEREST(S)

This work was financially supported by the Swedish Research Council (2017-00932), a joint grant from Region Stockholm and Karolinska Institutet (ALF Medicine 2020, FoUI-954072), Estonian Research Council (PRG1076), Horizon 2020 innovation (ERIN, EU952516) and European Commission and Enterprise Estonia (EU48695). The authors have no competing interests to declare for the current study.

Fertility and infertility implications in rheumatoid arthritis; state of the art

BACKGROUND

A bulk of investigations imply that women with rheumatoid arthritis (RA) deliver fewer children in comparison to healthy women.

PURPOSE

This review article attempts to clarify the involvement of infertility-related issues in both RA men and women. Moreover, the effect of RA disease on the fertility quality and quantity will be discussed.

RESULTS

Declined fertility rate in RA women seems to stem from modified inflammatory settings, advanced maternal age, limited sexual activity, and adverse effects of drugs on ovarian function. Women with RA may have smaller families and seem to be slower to conceive relative to their peer women. The chance of gestation in RA women may drop due to suppressed sexual function through pain and fatigue. In addition, treatment of RA women with non-steroidal anti-inflammatory drugs (NSAIDs) may prevent ovulation and therefore hinder the conception.

CONCLUSIONS

A complex interaction between RA disease and fertility related issues is present. Despite an increase rate of infertility in RA females or males, the mechanisms involved in this outcome is still unknown. Plausible causes of the decreased fertility rate in RA patients might be due to inflammatory cytokines, suppressed sexual activity, drug treatments, mother age, personal choice, or a combination of these elements.

Uterine fibroid management: from the present to the future

Uterine fibroids (also known as leiomyomas or myomas) are the most common form of benign uterine tumors. Clinical presentations include abnormal bleeding, pelvic masses, pelvic pain, infertility, bulk symptoms and obstetric complications.Almost a third of women with leiomyomas will request treatment due to symptoms. Current management strategies mainly involve surgical interventions, but the choice of treatment is guided by patient's age and desire to preserve fertility or avoid 'radical' surgery such as hysterectomy. The management of uterine fibroids also depends on the number, size and location of the fibroids. Other surgical and non-surgical approaches include myomectomy by hysteroscopy, myomectomy by laparotomy or laparoscopy, uterine artery embolization and interventions performed under radiologic or ultrasound guidance to induce thermal ablation of the uterine fibroids.There are only a few randomized trials comparing various therapies for fibroids. Further investigations are required as there is a lack of concrete evidence of effectiveness and areas of uncertainty surrounding correct management according to symptoms. The economic impact of uterine fibroid management is significant and it is imperative that new treatments be developed to provide alternatives to surgical intervention.There is growing evidence of the crucial role of progesterone pathways in the pathophysiology of uterine fibroids due to the use of selective progesterone receptor modulators (SPRMs) such as ulipristal acetate (UPA). The efficacy of long-term intermittent use of UPA was recently demonstrated by randomized controlled studies.The need for alternatives to surgical intervention is very real, especially for women seeking to preserve their fertility. These options now exist, with SPRMs which are proven to treat fibroid symptoms effectively. Gynecologists now have new tools in their armamentarium, opening up novel strategies for the management of uterine fibroids.

Investigational hormone receptor agonists as ongoing female contraception: a focus on selective progesterone receptor modulators in early clinical development

INTRODUCTION

As efforts are made to continue to increase the safety of contraceptive methods, those without estrogen have attracted new attention. Progestin-only options are available in many delivery systems, but most cause disturbed bleeding patterns. For gynecologic patients, selective progesterone receptor modulators (SPRMs) have been approved for medical abortion, for ovulation suppression in emergency contraception, and for the treatment of heavy menstrual bleeding due to leiomyoma.

AREAS COVERED

This article discusses the role of SPRMs in controlling fertility on an ongoing basis with particular emphasis on mifepristone and ulipristal acetate (UPA), since none of the other compounds has progressed out of early Phase I - II testing. It also discusses important information about the mechanisms of action and safety of these two SPRMs.

EXPERT OPINION

Of all the investigational hormone agonist/antagonists, SPRMs have demonstrated the greatest potential as ongoing female contraceptives. They have the ability to suppress ovulation after initiation of the luteinizing hormone (LH) surge without affecting ovarian production of estrogen or inducing any significant metabolic changes. SPRMs may well be able to provide longer term contraception as oral agents, vaginal rings, and perhaps even intrauterine devices. UPA has the greatest promise. Current research needs to be expanded.

Fertility and infertility in rheumatoid arthritis

PURPOSE OF REVIEW

Despite decades of evidence suggesting that women with rheumatoid arthritis (RA) have fewer children than their healthy peers, this information is not widely known among clinicians. The causes of decreased fertility in this population have been largely unexplored, but likely revolve around altered inflammation, increased age when conception is attempted, limited sexual function, and possibly medications limiting ovarian function.

RECENT FINDINGS

Several large Scandinavian cohorts and a cohort study in the United States demonstrate that women with RA have smaller families and are slower to conceive compared with other women. Personal choice to limit family size plays some role, as does infertility. Sexual function in women with RA is hampered by pain and fatigue, perhaps decreasing the opportunity for conception. Finally, data about the role of NSAIDs in preventing ovulation suggest that continued use of these medications may hinder conception.

SUMMARY

Infertility in women with RA is an under-recognized, but remarkably common phenomenon. Although research continues into the underlying causes, physicians can discuss this topic and refer women to reproductive endocrinology when needed, thereby helping patients to build the families that they desire.

The immninent dawn of SPRMs in obstetrics and gynecology

Selective progesterone receptor modulators (SPRMs) have been developed since the late 70s when mifepristone was first described. They act through nuclear progesterone receptors and can have agonist or mixed agonist antagonist actions depending on the cell and tissue. Mifepristone has unique major antagonist properties allowing its use for pregnancy termination. Ulipristal acetate has been marketed in 2009 for emergency contraception and has been recently approved for preoperative myoma treatment. Further perspectives for SPRMs use include long term estrogen free contraception, endometriosis treatment. However long term applications will be possible only after confirmation of endometrial safety.

Endometrial effects of a single early luteal dose of the selective progesterone receptor modulator CDB-2914

OBJECTIVE

To test potential contraceptive mechanisms of the selective P receptor modulator CDB-2914 in the early luteal phase.

DESIGN

Prospective randomized clinical trial.

SETTING

Clinical research center.

PATIENT(S)

Fifty-six women with regular cycles.

INTERVENTION(S)

Women received a single dose of CDB-2914 (10, 50, or 100 mg) or placebo given after ovulation and within 2 days of the LH surge. Four to 6 days later, a transvaginal ultrasound scan measured endometrial thickness, and an endometrial biopsy specimen was obtained.

MAIN OUTCOME MEASURE(S)

The endometrium was evaluated by thickness and by immunohistochemical analysis for P-dependent markers; safety laboratory tests were performed, and E(2) and P levels were obtained.

RESULT(S)

CDB-2914 caused a significant dose-dependent decrease in endometrial thickness, an increase in glandular P receptors, and a decrease in peripheral node addressins. Estradiol and P levels and menstrual cycle timing were not altered. No adverse effects were observed.

CONCLUSION(S)

The alteration in endometrial thickness and P-dependent markers of implantation in the absence of changes in hormone levels and cycle length suggests that CDB-2914 may have contraceptive properties.

Mifepristone attenuates human chorionic gonadotropin–induced extracellular signal–regulated kinase 1/2 phosphorylation, cyclooxygenase-2, and prostaglandin E2 production in human granulosa luteal cells

OBJECTIVE

To elucidate the role of RU486 in regulating the function of granulosa luteal cells and its possible involvement in ovarian dysfunction.

DESIGN

An in vitro study.

SETTING

University hospital.

PATIENT(S)

Our subjects were women under the age of 40 who were unable to get pregnant as a result of male-factor infertility.

INTERVENTION(S)

HCG and RU486 were added to cultured granulosa luteal cells; after incubation for 12 hours, the harvested cells were subjected to total mRNA and protein measurements.

MAIN OUTCOME MEASURE(S)

Reverse transcriptase-polymerase chain reaction, immunoblot assay, immunocytochemistry, and enzyme immunoassay were performed.

RESULT(S)

RU486 attenuates hCG-induced cyclooxygenase-2 (COX-2) mRNA and protein expression and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation and decreases the hCG-induced prostaglandin E2 (PGE2) production in a dose-dependent manner. RU486 treatment had no significant effect on COX-1 mRNA expression.

CONCLUSION(S)

Treatments using gonadotropins are able to induce ERK1/2 phosphorylation resulting in increased COX-2 protein expression and prostaglandin synthesis. RU486 attenuates the activation of ERK1/2, decreases the expression of COX-2, and affects PGE2 production by inhibiting hCG-induced COX-2 expression.

Emergency contraception in Cuba with 10 mg of mifepristone

BACKGROUND

Mifepristone in a dose of 10 mg is an effective emergency contraceptive when administered up to 120 hours after unprotected coitus.

METHODS

Between May 2003 and February 2005, we conducted in Cuba a single-arm trial to evaluate the effectiveness of 10 mg mifepristone for emergency contraception up to 6 days after unprotected coitus. A total of 635 women who requested emergency contraception after a single act of unprotected intercourse were included in the study.

RESULTS

After treatment there were 7/635 (1.1%) pregnancies (95% CI 0.4-2.3%). Pregnancy that might have occurred was prevented in 88.0% of the cases (95% CI 77.1-95.1%). The most common side effects reported by participants were fatigue (10.7%), dizziness (6.1%) and nausea (4.9%); vomiting was only reported by 0.6%. In 38/635 (6.0%) women menstruation was delayed more than 7 days.

CONCLUSIONS

Mifepristone 10 mg administered is an effective emergency contraceptive with an acceptable profile of side effects up to five days, but greater studies are necessary to verify its efficacy up to 6 days after unprotected intercourse.

Leukaemia inhibitory factor receptor and gp130 in the human Fallopian tube and endometrium before and after mifepristone treatment and in the human preimplantation embryo

Leukaemia inhibitory factor (LIF) is a cytokine, which is associated with reproductive processes such as embryo development and implantation. The objectives of this study were to detect the presence of LIF receptor (LIFR) and glycoprotein 130 (gp 130) in the human Fallopian tube, endometrium and preimplantation embryo and to study the effect of mifepristone on the expression of LIFR and gp130 in the Fallopian tube. Twenty-two healthy fertile women received a single dose of 200 mg mifepristone or placebo immediately after ovulation (LH + 2). Biopsies were obtained from the Fallopian tubes during laparoscopic sterilization once between days LH + 4 and LH + 6 and from endometrium once between days LH + 6 and LH + 8. Preimplantation embryos were received from couples undergoing in vitro fertilization treatment. Immunohistochemistry was used to detect the presence of LIFR and gp130 in the Fallopian tube, endometrium and preimplantation embryo. Real-time PCR was used to study LIFR and gp130 expression in the Fallopian tube and endometrium. LIFR and gp130 were localized in the Fallopian tube, preimplantation embryo and endometrium. LIFR was more abundant in the Fallopian tube than in the endometrium. In the blastocyst, the staining of gp130 was mainly localized in the inner cell mass, whereas LIFR was expressed in all cells. The presence of LIFR and gp130 in the Fallopian tube and preimplantation embryo indicates a role for LIF in communication between the embryo and the Fallopian tube. Mifepristone did not affect the expression of LIFR and gp130 in the Fallopian tube, nor in the endometrium suggesting that progesterone might not be directly involved in the regulation of LIFR or gp130.

Expression of aquaporin 2 in human endometrium

OBJECTIVE

To study the expression of aquaporin-2 (AQP2) in human endometrium.

DESIGN

Prospective clinical study.

SETTING

Hospital-based unit for gynecology and obstetrics and research laboratories.

PATIENT(S)

Healthy women with proven fertility who were divided into four groups according to LH peak.

INTERVENTION(S)

Endometrial biopsies were obtained from 34 women on cycle days LH+4 to LH+14.

MAIN OUTCOME MEASURE(S)

Localization of AQP2 in human endometrium during normal cycle using immunohistochemistry, verification of AQP2 expression through detection of AQP2 mRNA in reverse transcriptase-polymerase chain reaction (RT-PCR), detection of pinopodes using scanning electron microscopy, and confirmation of AQP2 on pinopodes in confocal microscopy.

RESULT(S)

Immunostaining of AQP2 is present in the luminal and glandular epithelium but not in the stroma. Some vessels stained positive for AQP2. When present, pinopodes stained positive, which was confirmed using confocal microscopy. A significant increase in staining intensity was seen in the glandular and luminal epithelium during the mid and late luteal phases of the cycle. The presence of AQP2 in human endometrium was also confirmed by RT-PCR.

CONCLUSION(S)

AQP2 is present in the human endometrium. The expression of AQP2 appears to be cycle dependent and suggests a role for AQP2 in implantation, edema, and/or menstruation.

Prostaglandin E2 and F2alpha receptors in the human Fallopian tube before and after mifepristone treatment

Prostaglandins are associated with several reproductive processes in addition to their effects on the vascular system and muscular contractility. The aim of this study was to gain information about the localization of the receptors for PGE(2) (EP1-EP4) and PGF(2alpha) (FP) in the human Fallopian tube and their regulation following treatment with mifepristone. Sixteen healthy fertile women received a single dose of 200 mg mifepristone or placebo immediately after ovulation (LH+2). Laparoscopic sterilization was performed on days LH+4 to LH+6. Biopsies were taken from the Fallopian tubes bilaterally. The expression of EP1, EP2, EP3, EP4 and FP was analysed using immunohistochemistry and RT-PCR. The co-localization of prostaglandin receptors and c-kit or e-nos was analysed using confocal microscopy. The effect of progesterone, mifepristone and prostaglandin on tubal contractility was studied. The presence of EP1-EP4 and FP in the Fallopian tube was detected using immunostaining. The receptors were expressed in serosal cells, luminal epithelial cells, and the muscular wall and vessels of the Fallopian tube. Co-localization studies showed that the endothelial cells stained positive for EP1-EP4 and FP and that co-localization was seen for EP4 and c-kit. Decreased contractility was seen after progesterone treatment, whereas increased contractility was seen after PGF(2alpha) and PGE(2) treatment. These data suggest that both the transport of the embryo and the communication between the embryo and the Fallopian tube involve the action of prostaglandins through EP and FP receptors in addition to the effect of prostaglandins on the vascular system and muscular contractility.

Endometrial receptivity: Clinical assessment in relation to fertility, infertility, and antifertility

Fertility in humans and other mammalian species depends absolutely on synchronous events that render the developing blastocyst and the receiving uterus competent for implantation. Endometrial receptivity is defined as the period during which the endometrial epithelium acquires functional, but transient, ovarian steroid-dependent status supportive to blastocyst acceptance and implantation. Once inside the uterus, the blastocyst is surrounded by an intact luminal epithelium, which is considered to act as barrier to its attachment, except for this short period of high endometrial receptivity to blastocyst signal(s). Its transport and permeability properties, in conjunction with cellular action of the endometrium and the embryo, have been suggested to influence creation and maintenance of informational and nutritional status of uterine luminal milieu. This period, also termed as the 'window of implantation,' is limited to days 20-24 of menstrual cycle in humans. However, establishment of endometrial receptivity is still a biological mystery that remains unsolved despite marked advances in our understanding of endometrial physiology following extensive research associated with its development and function. This review deals with various structural, biochemical, and molecular events in the endometrium coordinated within the implantation window that constitute essential elements in the repertoire that signifies endometrial receptivity and is aimed to achieve a better understanding of its relationship to fertility, infertility, and for the development of targeted antifertility agents for human use and welfare.

Selective progesterone receptor modulator development and use in the treatment of leiomyomata and endometriosis

Selective progesterone receptor modulators (SPRMs) represent a new class of progesterone receptor ligands. SPRMs exert clinically relevant tissue-selective progesterone agonist, antagonist, or mixed agonist/antagonist effects on various progesterone target tissues in vivo. Asoprisnil (J867) is the first SPRM to reach an advanced stage of clinical development for the treatment of symptomatic uterine fibroids and endometriosis. Asoprisnil belongs to the class of 11beta-benzaldoxime-substituted estratrienes that exhibit partial progesterone agonist/antagonist effects with high progesterone receptor specificity in animals and humans. Asoprisnil has no antiglucocorticoid activity in humans at therapeutic doses. It exhibits endometrial antiproliferative effects on the endometrium and breast in primates. Unlike progesterone antagonists, asoprisnil does not induce labor in relevant models of pregnancy and parturition. It induces amenorrhea primarily by targeting the endometrium. In human subjects with uterine fibroids, asoprisnil suppressed both the duration and intensity of uterine bleeding in a dose-dependent manner and reduced tumor volume in the absence of estrogen deprivation. In subjects with endometriosis, asoprisnil was effective in reducing nonmenstrual pain and dysmenorrhea. Asoprisnil may, therefore, provide a novel, tissue-selective approach to control endometriosis-related pain. SPRMs have the potential to become a novel treatment of uterine fibroids and endometriosis.

Hormonal regulation of implantation

Implantation is a complex process that requires synchronization between the embryo and a receptive endometrium. Hormones, such as the female sex steroids, prostaglandins, and peptide hormones, regulate the cellular and molecular mediators of endometrial receptivity, which include pinopodes, cell adhesion molecules, cytokines, homeobox genes, and growth factors. These mediators can be altered, despite the presence of normal hormone levels and endometrial histology; this limits the usefulness of the luteal phase endometrial biopsy. Therefore, analysis of markers of endometrial receptivity may predict successful implantation better. Elevated androgen and estrogen levels, as seen with polycystic ovary syndrome and controlled ovarian hyperstimulation, respectively, also can have detrimental effects on the endometrium, and therefore, implantation.

Mifepristone for luteal phase contraception

The concept of luteal phase contraception and the use of mifepristone in clinical trials, which allows for testing of its validity, as well as clinical pharmacological research designed to understand its mode of action, are reviewed. Early luteal phase administration has a variety of morphological, physiological and biochemical effects on the endometrium that are likely to interfere with embryonic-endometrial interactions. In fact, specifically designed pilot clinical trials as well as data derived from emergency contraception studies indicate that early luteal phase administration of mifepristone is highly effective in preventing pregnancy, with minimal disturbance of hormonal parameters or menstrual cyclicity. Mid and late luteal phase administration of mifepristone at doses above 25 mg are highly effective in inducing endometrial bleeding in nonconceptional cycles. However, administration of mifepristone within the period between implantation and expected menses fails to induce bleeding in a significant proportion of cases, and furthermore the bleeding induced does not insure the termination of pregnancy. While the data suggest there is potential for a once-a-month contraceptive pill, it is likely that no molecule endowed with partial agonistic properties, like mifepristone, will completely and reliably suppress the essential functions of progesterone in order to achieve contraceptive efficacy comparable to that of modern contraceptive methods.

Summary of evidence and research needs on the use of mifepristone in fertility regulation: consensus from the conference

The conference on the use of mifepristone to reduce unwanted pregnancy, sponsored by the World Health Organization, Concept Foundation and the Rockefeller Foundation, took place in Bellagio, Italy, between 24 and 28 September 2001. The objective of the conference was to review the scientific information and to evaluate the use of mifepristone for emergency contraception, luteal contraception and menstrual induction. Mifepristone is highly effective for emergency contraception but its advantages and disadvantages in comparison with levonorgestrel need to be further studied. Data indicate that mifepristone alone or in combination with misoprostol has potential for occasional use for women seeking help following repeated unprotected intercourse and/or when the interval between intercourse and treatment is more then 120 h. Administration of mifepristone immediately after ovulation seems to be an effective contraceptive method. However, before it can be used commonly, there is a need for a simple and inexpensive method to identify the right time in the cycle. Once-a-month treatment with mifepristone and misoprostol at the expected time of menstruation is not a practical method due to bleeding irregularities and timing of treatment. Menstrual induction with mifepristone and a suitable prostaglandin analogue is highly effective. A randomized comparison with manual vacuum aspiration is, however, needed before it can be recommended for routine use.

Mechanisms of action of mifepristone when used for emergency contraception

An emergency contraceptive method is used after coitus but before pregnancy occurs. The use of emergency contraception is largely underutilized worldwide. Recently, treatment with 10 mg mifepristone as a single dose has emerged as one of the most effective hormonal methods for emergency contraception, with very low side effects. However, the mechanism of action of mifepristone in humans when used for contraceptive purposes and especially for emergency contraception remains largely unknown. The objective of this review is to summarize available data on the effect of mifepristone on female reproductive functions relevant to emergency use of the compound. Taken together, available data from studies in humans indicate that the contraceptive effect of mifepristone used as a single low dose for emergency contraception is mainly due to impairment of ovarian function, either by blocking or postponing the luteinizing hormone surge, rather than to inhibiting of implantation.

Asoprisnil (J867): a selective progesterone receptor modulator for gynecological therapy

Asoprisnil is a novel selective steroid receptor modulator that shows unique pharmacodynamic effects in animal models and humans. Asoprisnil, its major metabolite J912, and structurally related compounds represent a new class of progesterone receptor (PR) ligands that exhibit partial agonist and antagonist activities in vivo. Asoprisnil demonstrates a high degree of receptor and tissue selectivity, with high-binding affinity for PR, moderate affinity for glucocorticoid receptor (GR), low affinity for androgen receptor (AR), and no binding affinity for estrogen or mineralocorticoid receptors. In the rabbit endometrium, both asoprisnil and J912 induce partial agonist and antagonist effects. Asoprisnil induces mucification of the guinea pig vagina and has pronounced anti-uterotrophic effects in normal and ovariectomized guinea pigs. Unlike antiprogestins, asoprisnil shows only marginal labor-inducing activity during mid-pregnancy and is completely ineffective in inducing preterm parturition in the guinea pig. Asoprisnil exhibits only marginal antiglucocorticoid activity in transactivation in vitro assays and animal models. In male rats, asoprisnil showed weak androgenic and anti-androgenic properties. In toxicological studies in female cynomolgus monkeys, asoprisnil treatment abolished menstrual cyclicity and endometrial atrophy. Early clinical studies of asoprisnil in normal volunteers demonstrated a dose-dependent suppression of menstruation irrespective of the effects on ovulation, with no change in basal estrogen concentrations and no antiglucocorticoid effects. Unlike progestins, asoprisnil does not induce breakthrough bleeding. With favorable safety and tolerability profiles thus far, asoprisnil appears promising as a novel treatment of gynecological disorders, such as uterine fibroids and endometriosis.

Effects of mifepristone on endometrial receptivity

At the development of receptivity the endometrium undergoes specific changes. Several factors have been suggested as markers of endometrial receptivity. A common feature for most of these factors is that they are directly, or indirectly, regulated by progesterone. The effect of various doses and regimens of mifepristone on endometrial development and markers of receptivity has been studied. Timed endometrial biopsies were assessed by immunhistochemistry, reverse transcriptase polymerase chain reaction (RT-PCR) and electron microscopy. In addition the contraceptive efficacy of these regimens was investigated. Administration of 200 mg of mifepristone immediately post ovulation has a pronounced effect on endometrial development and on suggested markers of receptivity. This regimen has been shown to be an effective contraceptive method. When 10 mg is given pre or post ovulation, only minor effects on the endometrium are observed. Our studies show that mifepristone, when administered in low doses that do not affect ovulation, significantly affects some of the studied markers of endometrial receptivity and reduces pregnancy rates; however, these activities are more pronounced with the higher dose, which is more effective. Our findings provide insight into the regulation of progesterone receptors of various suggested markers of endometrial receptivity and the possibility of using mifepristone for endometrial contraception.

Identification of a jasmonate-regulated allene oxide synthase that metabolizes 9-hydroperoxides of linoleic and linolenic acids

Allene oxide synthase (AOS) is a cytochrome P-450 (CYP74A) that catalyzes the first step in the conversion of 13-hydroperoxy linolenic acid to jasmonic acid and related signaling molecules in plants. Here, we report the molecular cloning and characterization of a novel AOS-encoding cDNA (LeAOS3) from Lycopersicon esculentum whose predicted amino acid sequence classifies it as a member of the CYP74C subfamily of enzymes that was hitherto not known to include AOSs. Recombinant LeAOS3 expressed in Escherichia coli showed spectral characteristics of a P-450. The enzyme transformed 9- and 13-hydroperoxides of linoleic and linolenic acid to alpha-ketol, gamma-ketol, and cyclopentenone compounds that arise from spontaneous hydrolysis of unstable allene oxides, indicating that the enzyme is an AOS. Kinetic assays demonstrated that LeAOS3 was approximately 10-fold more active against 9-hydroperoxides than the corresponding 13-isomers. LeAOS3 transcripts accumulated in roots, but were undetectable in aerial parts of mature plants. In contrast to wild-type plants, LeAOS3 expression was undetectable in roots of a tomato mutant that is defective in jasmonic acid signaling. These findings suggest that LeAOS3 plays a role in the metabolism of 9-lipoxygenase-derived hydroperoxides in roots, and that this branch of oxylipin biosynthesis is regulated by the jasmonate signaling cascade.

Mifepristone-induced vaginal bleeding is associated with increased immunostaining for cyclooxygenase-2 and decrease in prostaglandin dehydrogenase in luteal phase endometrium

The mechanism of mifepristone-induced vaginal bleeding and endometrial shedding was investigated in 13 women who took 200 mg mifepristone in the midluteal phase on d 8 after the onset of the urinary LH surge (LH+8). Endometrial biopsies were collected, 6-24 h after mifepristone (group 1, n = 7) or 36-48 h after mifepristone (group 2, n = 6), and compared with those from a control group in the midluteal phase (n = 7). All women reported vaginal bleeding commencing 36-48 h after taking mifepristone. Treatment with mifepristone significantly reduced serum progesterone levels in all women, when compared with the controls (13.2 nM vs. 34.8 nM, P = 0.001). After mifepristone, a significant increase in cyclooxygenase-2 immunoreactivity was apparent at 36-48 h (P = 0.0018), whereas prostaglandin 15 dehydrogenase enzyme-positive immunostaining declined, to be virtually absent by 36-48 h in both glands and in stroma (P < 0.05). There was no change in intensity or distribution of staining for steroid receptors after mifepristone. The changes in immunostaining for cyclooxygenase-2 and prostaglandin 15 dehydrogenase strongly support the hypothesis that an increase in the local concentration of prostaglandins in the endometrium is involved in the mechanism of bleeding induced by mifepristone in the luteal phase.

Formation of pinopodes in human endometrium is associated with the concentrations of progesterone and progesterone receptors

OBJECTIVE

To investigate the relation between the development of endometrial pinopodes and the serum concentration of hormones and the distribution of estrogen receptor-alpha, estrogen receptor-beta, progesterone receptor A, and progesterone receptor B.

DESIGN

Prospective clinical study.

SETTING

Hospital-based unit of reproductive health and university-affiliated reproductive research laboratories.

PATIENT(S)

Twenty-seven healthy fertile women with normal menstrual cycles.

INTERVENTION(S)

Urine and blood sampling for hormone measurement, vaginal ultrasonography, and endometrial biopsy.

MAIN OUTCOME MEASURE(S)

Appearance of the endometrium on light microscopy, pinopode formation, serum levels of luteinizing hormone (LH) and follicle stimulating hormone (FSH), and expression of progesterone receptors A and B and estrogen receptors alpha and beta.

RESULT(S)

Pinopode formation and regression were closely associated with increases and decreases, respectively, in serum progesterone concentration. At pinopode development, levels progesterone receptors A and B in the glandular and luminal epithelial cells decreased; this effect was mainly dependent on the absence of progesterone receptor B. Serum estrogen levels and levels of estrogen receptor alpha and beta did not correlate with pinopode formation.

CONCLUSION(S)

The increase in serum progesterone level and down-regulation of progesterone receptor B are important in development of pinopodes.

Contraceptive use of antiprogestin

OBJECTIVES

To study the effect of antiprogestin on ovarian function and endometrial development during the menstrual cycle and the possibility of using these compounds for contraceptive purposes.

METHODS

Administration of different doses of the antiprogestin mifepristone during the menstrual cycle; intermittent measurements of luteinizing hormone, progestin and estrogen in blood and/or urine; endometrial morphology and concentration of markers for endometrial receptivity; efficacy trials of the contraceptive effect of mifepristone.

RESULTS

A high dose of mifepristone administered in the follicular phase will inhibit follicular development. If mifepristone is given immediately after ovulation, the secretory development of the endometrium and the expression of, for instance, leukemia inhibitory factor and integrins will be inhibited. Similar effects on the endometrium are obtained with small weekly doses (2.5 or 5.0 mg) or small daily doses (0.5 mg) of mifepristone, which do not inhibit ovulation. Once-monthly administration of 200 mg mifepristone on the day after ovulation, and emergency postcoital treatment, are highly effective methods for preventing pregnancy. Even 5 mg once weekly has a significant contraceptive effect.

CONCLUSIONS

The antiprogestin mifepristone has a number of effects during the menstrual cycle which makes the compound suitable for contraceptive use. Treatment after a single act of unprotected intercourse, and once-a-month treatment immediately after ovulation, have shown high contraceptive efficacy. A low-dose regimen which does not influence ovulation also has a contraceptive effect, but the efficacy needs to be improved before routine clinical use.

Antinidatory effect of luteal phase administration of mifepristone (RU486) is associated with changes in endometrial prostaglandins during the implantation window

Luteal phase administration of mifepristone provides a significant degree of pregnancy protection to monkeys and women. Among several proposed mediators of the antinidatory action of luteal phase mifepristone, prostaglandins (PG) at the endometrial level appear important, and was examined in the present study using the rhesus monkey as the primate model. To this end, the concentrations of PGE2 and PGF2 alpha in endometrium and the profiles of cyclooxygenase (COX) and 15-hydroxy prostaglandin dehydrogenase (PGDH) were examined in untreated control animals, in animals subjected to mifepristone treatment (2 mg/day) alone or along with diclofenac (25 mg/day), or along with a PGE1 analog (100 micrograms misoprostol), in animals subjected to diclofenac alone treatment, and in animals treated with misoprostol alone on cycle days 16, 17, and 18. Tissue samples were collected on day 20 of treatment cycles from animals with discernible corpora lutea. Early luteal phase treatment with diclofenac did not result in any remarkable change in endometrial prostaglandin concentrations, however, there was an increase in the profile of COX. Animals exposed to misoprostol in the prereceptive stage, on the other hand, exhibited decreased expression of endometrial COX. The concentrations of PGF2 alpha and PGE2, as well as the ratios of PGF2 alpha to PGE2 concentrations, were increased along with a decrease in COX and PGD in endometrial samples following luteal phase mifepristone treatment. Although the underlying cellular mechanism of regulation of COX and PGDH in mifepistone-treated endometrium remains to be examined, the decrease in PG catabolism through low PGDH may contribute to the increased PG and high ratio of PGF2 alpha to PGE2 in mifepristone-exposed endometrium. It is plausible that mifepristone action on endometrial cells is mediated by an altered ratio of PGF2 alpha to PGE2. Furthermore, it appears that the regulation of PG milieu by COX and PGDH activities in reproductive tissues is under complex regulatory mechanism and is temporarily correlated with specific developmental events.

Anti-implantation activity of luteal phase mifepristone administration is not mimicked by prostaglandin synthesis inhibitor or prostaglandin analogue in the rhesus monkey

The use of mifepristone as an anti-implantation agent in the primate has been explored in the rhesus monkey with two specific aims: (i) to determine the contraceptive efficacy of very low-dose mifepristone administered on mated cycle days 16, 17, and 18; and (ii) to test the hypothesis that alteration in endometrial prostaglandin milieu by using either prostaglandin analogue or prostaglandin synthesis inhibitor can intervene the antifertility effect induced by mifepristone. Thirty female monkeys were randomly assigned to one of the six treatment groups. Five monkeys in the control group (group 1) were subjected to mating during cycle days 8-22. Four out of five monkeys became pregnant in the first mated cycle (80%) with detection of serum mCG by 12.7 +/- 1.5 days after ovulation. In group 2, 12 mated cycles were studied in five monkeys, mifepristone [RU486, 2 mg/day/animal, s.c. in 1 ml vehicle (1:4, benzyl benzoate:olive oil, v/v)] was given on cycle days 16, 17, and 18. In this group, no pregnancy was observed, thus providing complete pregnancy protection. Though there was an apparent extension of treatment cycle lengths in five cases with no incidence of inter-menstrual bleeding or spotting, there were no significant changes in serum estradiol (E) and progesterone (P). In group 3, four monkeys received prostaglandin (PG) synthesis inhibitor, diclofenac sodium (D, 25 mg/day/animal, i.m.) on cycle days 16, 17, and 18 in seven ovulatory menstrual cycles. Four of these cycles (57%) resulted in normal pregnancies; however, mCG detection (16.8 +/- 1.2 days after ovulation) was significantly (p < 0.05) delayed as compared to group 1. In group 4, four monkeys received 100 micrograms misoprostol (M), a PGE1 analogue, by gavage on mated cycle days 16, 17, and 18. Four pregnancies occurred in five treatment cycles (80%) with normal profiles of serum E and Pi mCG was first detected 13.2 +/- 1.7 days after ovulation. In group 5, seven monkeys received same dosages of RU486 and D on mated cycle days 16, 17, and 18. One hundred percent pregnancy protection was observed with luteal phase lengthening in eight treatment cycles but with unaltered E and P profiles. In group 6, five monkeys in nine treatment cycles received same dosages of RU486 and M on mated cycle days 16, 17, and 18. One pregnancy occurred; evaluation of E and P levels showed that the drug was given in the preovulatory period, which delayed ovulation and implantation, as mCG was detected 19 days post-ovulation. A delay in vaginal bleeding was observed in four treatment cycles with unaltered E and P profiles. Low-dose mifepristone appears to be a potential candidate for luteal phase and post-coital emergency contraception. However, the hypothesis that altered endometrial prostaglandin milieu may be responsible for mediating the anti-implantation effect of RU486 does not appear to be tenable based on our results in the rhesus monkey.

Contraception with anti-progesterone

Anti-progesterones have potential as contraceptives, acting either by the inhibition of ovulation or the inhibition of endometrial development. Clinical studies have shown that once-a-month treatment with Mifepristone in the early luteal phase is an effective contraceptive method, and that emergency post-coital contraception with Mifepristone is at least as effective as other methods currently used. Recent studies indicate that the endometrium is more susceptible to Mifepristone than are the hypothalamic and pituitary regions, and it may therefore be possible to develop a new contraceptive method based on low daily or once-weekly doses of Mifepristone that does not influence ovarian function.