Cyclical progestogens for heavy menstrual bleeding.

BACKGROUND: Heavy menstrual bleeding (HMB) is a menstrual blood loss perceived by women as excessive that affects the health of women of reproductive age, interfering with their physical, emotional, social and material quality of life. Whilst abnormal menstrual bleeding may be associated with underlying pathology, in the present context, HMB is defined as excessive menstrual bleeding in the absence of other systemic or gynaecological disease. The first-line therapy is usually medical, avoiding possibly unnecessary surgery. Of the wide variety of medications used to reduce HMB, oral progestogens were originally the most commonly prescribed agents. This review assesses the effectiveness of two different types and regimens of oral progestogens in reducing ovulatory HMB.This is the update of a Cochrane review last updated in 2007, and originally named "Effectiveness of cyclical progestagen therapy in reducing heavy menstrual bleeding" (1998). OBJECTIVES: To determine the effectiveness, safety and tolerability of oral progestogen therapy taken either during the luteal phase (short cycle) or for a longer course of 21 days per cycle (long cycle), in achieving a reduction in menstrual blood loss in women of reproductive age with HMB. SEARCH METHODS: In January 2019 we searched Cochrane Gynaecology and Fertility's specialized register, CENTRAL, MEDLINE, Embase, CINAHL and PsycInfo. We also searched trials registers, other sources of unpublished or grey literature and reference lists of retrieved trials. We also checked citation lists of review articles to identify trials. SELECTION CRITERIA: Randomized controlled trials (RCTs) comparing different treatments for HMB that included cyclical oral progestogens were eligible. DATA COLLECTION AND ANALYSIS: Two review authors independently selected trials for inclusion, assessed trials for risk of bias and extracted data. We contacted trial authors for clarification of methods or additional data when necessary. We only assessed adverse events if they were separately measured in the included trials. We compared cyclical oral progestogen in different regimens and placebo or other treatments. Our primary outcomes were menstrual blood loss and satisfaction with treatment; the secondary outcomes were number of days of bleeding, quality of life, compliance and acceptability of treatment, adverse events and costs. MAIN RESULTS: This review identified 15 randomized controlled trials (RCTs) with 1071 women in total. Most of the women knew which treatment they were receiving, which may have influenced their judgements about menstrual blood loss and satisfaction. Other aspects of trial quality varied among trials.We did not identify any RCTs comparing progestogen treatment with placebo. We assessed comparisons between oral progestogens and other medical therapies separately according to different regimens.Short-cycle progestogen therapy during the luteal phase (medroxyprogesterone acetate or norethisterone for 7 to 10 days, from day 15 to 19) was inferior to other medical therapy, including tranexamic acid, danazol and the progestogen-releasing intrauterine system (Pg-IUS (off of the market since 2001)), releasing 60 mcg of progesterone daily, with respect to reduction of menstrual blood loss (mean difference (MD) 37.29, 95% confidence interval (CI) 17.67 to 56.91; I2 = 50%; 6 trials, 145 women). The rate of satisfaction and the quality of life with treatment was similar in both groups. The number of bleeding days was greater on the short cycle progestogen group compared to other medical treatments. Adverse events (such as gastrointestinal symptoms and weight gain) were more likely with danazol when compared with progestogen treatment. We note that danazol is no longer in general use for treating HMB.Long-cycle progestogen therapy (medroxyprogesterone acetate or norethisterone), from day 5 to day 26 of the menstrual cycle, is also inferior to the levonorgestrel-releasing intrauterine system (LNG-IUS), releasing tranexamic acid and ormeloxifene, but may be similar to the combined vaginal ring with respect to reduction of menstrual blood loss (MD 16.88, 95% CI 10.93 to 22.84; I2 = 87%; 4 trials, 355 women). A higher proportion of women taking norethisterone found their treatment unacceptable compared to women having Pg-IUS (Peto odds ratio (OR) 0.12, 95% CI 0.03 to 0.40; 1 trial, 40 women). However, the adverse effects of breast tenderness and intermenstrual bleeding were more likely in women with the LNG-IUS. No trials reported on days of bleeding or quality of life for this comparison.The evidence supporting these findings was limited by low or very low gradings of quality; thus, we are uncertain about the findings and there is a potential that they may change if we identify other trials. AUTHORS' CONCLUSIONS: Low- or very low-quality evidence suggests that short-course progestogen was inferior to other medical therapy, including tranexamic acid, danazol and the Pg-IUS with respect to reduction of menstrual blood loss. Long cycle progestogen therapy (medroxyprogesterone acetate or norethisterone) was also inferior to the LNG-IUS, tranexamic acid and ormeloxifene, but may be similar to the combined vaginal ring with respect to reduction of menstrual blood loss.

Abnormal uterine bleeding.

Introduction: It is not uncommon for a woman to suffer from abnormal uterine bleeding (AUB) or heavy menstrual bleeding (HMB) at some point during her lifetime. Once pathology is excluded, in practice, management needs to be individualised, taking into account the improvement of the woman's symptoms and quality of life. Sources of data: Peer-reviewed journals, governmental and professional society publications. Areas of agreement: There is now agreement on a structured, universal approach to the diagnosis of AUB, with the aide memoirs PALM (polyps, adenomyosis, leiomyoma, malignancy) and COEIN (coagulopathies, ovulatory dysfunction, endometrial, iatrogenic, not otherwise classified). Once malignancy and significant pelvic pathology have been ruled out, medical treatment is an effective first-line therapeutic option, with surgery, including endometrial ablation and hysterectomy, offered when medical management has failed to resolve symptoms and fertility is no longer desired. Areas of controversy: There remains controversy around the management of the types and subtypes of adenomyosis and leiomyoma, and understanding their impact on clinical reproductive outcomes. Areas currently under development: Standardised assessment tools for measuring outcomes of AUB are being developed. Areas timely for developing research: Novel diagnostic and monitoring tools should be developed to help stratify treatment for women with AUB, particularly relating to 'unclassified' and 'endometrial' causes.

Uterine NK cells regulate endometrial bleeding in women and are suppressed by the progesterone receptor modulator asoprisnil.

Uterine NK cells (uNK) play a role in the regulation of placentation, but their functions in nonpregnant endometrium are not understood. We have previously reported suppression of endometrial bleeding and alteration of spiral artery morphology in women exposed to asoprisnil, a progesterone receptor modulator. We now compare global endometrial gene expression in asoprisnil-treated versus control women, and we demonstrate a statistically significant reduction of genes in the IL-15 pathway, known to play a key role in uNK development and function. Suppression of IL-15 by asoprisnil was also observed at mRNA level (p < 0.05), and immunostaining for NK cell marker CD56 revealed a striking reduction of uNK in asoprisnil-treated endometrium (p < 0.001). IL-15 levels in normal endometrium are progesterone-responsive. Progesterone receptor (PR) positive stromal cells transcribe both IL-15 and IL-15RA. Thus, the response of stromal cells to progesterone will be to increase IL-15 trans-presentation to uNK, supporting their expansion and differentiation. In asoprisnil-treated endometrium, there is a marked downregulation of stromal PR expression and virtual absence of uNK. These novel findings indicate that the IL-15 pathway provides a missing link in the complex interplay among endometrial stromal cells, uNK, and spiral arteries affecting physiologic and pathologic endometrial bleeding.

Access to and sustainability of abortion services: a systematic review and meta-analysis for the National Institute of Health and Care Excellence-new clinical guidelines for England.

BACKGROUND: Induced abortion is a common procedure. However, there is marked variation in accessibility of services across England. Accessing abortion services may be difficult, particularly for women who live in remote areas, are in the second trimester of pregnancy, have complex pre-existing conditions or have difficult social circumstances. OBJECTIVE AND RATIONALE: This article presents a two-part review undertaken for a new National Institute of Health and Care Excellence guideline on abortion care, and aiming to determine: the factors that help or hinder accessibility and sustainability of abortion services in England (qualitative review), and strategies that improve these factors, and/or other factors identified by stakeholders (quantitative review). Economic modelling was undertaken to estimate cost savings associated with reducing waiting times. SEARCH METHODS: Ovid Embase Classic and Embase, Ovid MEDLINE(R) Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R), PsycINFO, Cochrane Library via Wiley Online, Cinahl Plus and Web of Science Core Collection were searched for articles published up to November 2018. Studies were included if they were published in English after 2001, conducted in Organization for Economic Co-operation and Development (OECD) countries and were: qualitative studies reporting views of patients and/or staff on factors that help or hinder the accessibility and sustainability of a safe abortion service, or randomized or non-randomized studies that compared strategies to improve factors identified by the qualitative review and/or stakeholders. Studies were excluded if they were conducted in OECD countries where abortion is prohibited altogether or only performed to save the woman's life. One author assessed risk of bias of included studies using the following checklists: Critical Appraisal Skills Programme checklist for qualitative studies, Cochrane Collaboration quality checklist for randomized controlled trials, Newcastle-Ottawa scale for cohort studies, and Effective Practice and Organization of Care risk of bias tool for before-and-after studies.Qualitative evidence was combined using thematic analysis and overall quality of the evidence was assessed using Grading of Recommendations, Assessment, Development and Evaluations (GRADE) Confidence in the Evidence from Reviews of Qualitative Research (CERQual). Quantitative evidence was analysed in Review Manager 5.3 and overall quality of evidence was assessed using GRADE. OUTCOMES: Eight themes (service level barriers; financial barriers; logistical barriers; personal barriers; legal and policy barriers; privacy and confidentiality concerns; training and education; community prescribing and telemedicine introduce greater flexibility) and 18 subthemes were identified from 23 papers (n = 1016) included in the qualitative review. The quality of evidence ranged from very low to high, with evidence for one theme and seven subthemes rated as high quality. Nine studies (n = 7061) were included in the quantitative review which showed that satisfaction was better (low to high quality evidence) and women were seen sooner (very low quality evidence) when care was led by nurses or midwives compared with physician-led services, women were seen sooner when they could self-refer (very low quality evidence), and clinicians were more likely to provide abortions if training used an opt-out model (very low quality evidence). Economic modelling showed that even small reductions in waiting times could result in large cost savings for services. WIDER IMPLICATIONS: Self-referral, funding for travel and accommodation, reducing waiting times, remote assessment, community services, maximizing the role of nurses and midwives and including practical experience of performing abortion in core curriculums, unless the trainee opts out, should improve access to and sustainability of abortion services.

Stimulation of lactate production in human granulosa cells by metformin and potential involvement of adenosine 5' monophosphate-activated protein kinase.

CONTEXT: Production of 3-carbon units (as lactate) by granulosa cells (GCs) is important in follicular and oocyte development and may be modulated by metformin. OBJECTIVE: The aim of the study was to examine the action of metformin on GC lactate production and potential mediation via AMP-activated protein kinase (AMPK). DESIGN: GCs were prepared from follicular aspirates. After exposure to metformin and other potential modulators of AMPK in culture, aspects of cellular function were examined. SETTING: The study was conducted in a private fertility clinic/university academic center. PATIENTS: Women undergoing routine in vitro fertilization participated in the study. INTERVENTIONS: All agents were added in culture. MAIN OUTCOME MEASURES: Lactate output of GCs was measured. Cell extracts were prepared after culture, and phosphorylated forms of AMPK and acetyl CoA carboxylase (ACC) were assayed using Western analysis. RESULTS: Metformin led to a rapid increase in lactate production by GCs [minimum effective dose, 250 microm; maximum dose studied, 1 mm (1.22-fold; P < 0.01)]. This dose range of metformin was similar to that required for stimulation of phospho-AMPK in GCs [minimum effective dose, 250 microm; maximum effect, 500 microm (2.01-fold; P < 0.001)]. Increasing phospho-ACC, as a representative downstream target regulated by AMPK, was apparent over a lower range (minimum effective dose, 31 microm; maximum effect, 250 microm; P < 0.001). A level of metformin (125 microm) insufficient for the stimulation of lactate output when used alone potentiated the effects of suboptimal doses of insulin on lactate production. Adiponectin (2.5 microg/ml) had a small but significant effect on lactate output. CONCLUSIONS: Metformin activates AMPK in GCs, stimulating lactate production and increasing phospho-ACC. Metformin also enhances the action of suboptimal insulin concentrations to stimulate lactate production.

In humans, early cortisol biosynthesis provides a mechanism to safeguard female sexual development.

In humans, sexual differentiation of the external genitalia is established at 7-12 weeks post conception (wpc). During this period, maintaining the appropriate intrauterine hormone environment is critical. In contrast to other species, this regulation extends to the human fetal adrenal cortex, as evidenced by the virilization that is associated with various forms of congenital adrenal hyperplasia. The mechanism underlying these clinical findings has remained elusive. Here we show that the human fetal adrenal cortex synthesized cortisol much earlier than previously documented, an effect associated with transient expression of the orphan nuclear receptor nerve growth factor IB-like (NGFI-B) and its regulatory target, the steroidogenic enzyme type 2 3beta-hydroxysteroid dehydrogenase (HSD3B2). This cortisol biosynthesis was maximal at 8-9 wpc under the regulation of ACTH. Negative feedback was apparent at the anterior pituitary corticotrophs. ACTH also stimulated the adrenal gland to secrete androstenedione and testosterone. In concert, these data promote a distinctive mechanism for normal human development whereby cortisol production, determined by transient NGFI-B and HSD3B2 expression, provides feedback at the anterior pituitary to modulate androgen biosynthesis and safeguard normal female sexual differentiation.

Effects of the selective progesterone receptor modulator asoprisnil on uterine artery blood flow, ovarian activity, and clinical symptoms in patients with uterine leiomyomata scheduled for hysterectomy.

INTRODUCTION: Asoprisnil, a novel orally active selective progesterone receptor modulator, is being studied for the management of symptomatic uterine leiomyomata. The exact mechanism of action is not yet discerned. The primary objectives of this double-blind, randomized, placebo-controlled study included evaluation of the effect of asoprisnil on uterine artery blood flow. Furthermore, we assessed effects of asoprisnil on leiomyoma symptoms. PATIENTS AND METHODS: Thirty-three premenopausal patients scheduled for hysterectomy due to symptomatic uterine leiomyomata were recruited in four centers and treated with 10 or 25 mg asoprisnil or placebo for 12 wk before surgery. At baseline and before hysterectomy, all patients underwent sonographic assessment to measure impedance to uterine artery blood flow, determined by resistance index and pulsatility index, as well as volumes of largest leiomyoma and uterus. In addition, patients recorded intensity and frequency of menstrual bleeding on a menstrual pictogram. Each asoprisnil treatment was compared with placebo. RESULTS: The increased pulsatility index in both asoprisnil groups and the statistically significantly increased resistance index within the 25-mg asoprisnil group suggest a moderately decreased uterine artery blood flow. Analysis of menstrual pictogram scores showed a statistically significant larger decrease in frequency and intensity of bleeding for both asoprisnil groups compared with placebo. Bleeding was suppressed by asoprisnil 25mg in 91% of patients. Asoprisnil treatment was well tolerated when administered daily for a 12-wk period, and no serious adverse events occurred. CONCLUSION: Asoprisnil moderately reduced uterine artery blood flow. This effect may contribute in part to the clinical effects of asoprisnil.

Quantitated transcript haplotypes (QTH) of AGTR1, reduced abundance of mRNA haplotypes containing 1166C (rs5186:A>C), and relevance to metabolic syndrome traits.

The angiotensin II type 1 receptor (AGTR1) is the main target through which angiotensin II influences cardiovascular tone, cell growth, and fluid and electrolyte balance. AGTR1 polymorphism has been reported to associate with hypertension, myocardial infarction (MI), and metabolic traits. Here we describe a novel approach to quantitation of transcript haplotypes (QTH) of AGTR1. To determine relative allelic expression from haplotypes, within-individual-between-allele ratiometric analyses in placental cDNA were developed for the transcribed SNPs rs5182:C>T (encoding p.L191) and rs5186:A>C (3'-noncoding "A1166C"). Additionally, between-individual comparisons were made using TaqMan assays applied to both homozygous and heterozygous genotypes and haplotypes. In conjunction, linkage disequilibrium (LD) and genomic haplotype associations with metabolic syndrome were examined. There was no significant difference of mRNA level for alleles of rs5182:C>T, but allele and mRNA haplotypes carrying 1166C exhibited reduced abundance. The effect was much greater in CC homozygotes than in heterozygotes. The promoter region was confirmed to be in a separate haplotype block from the AGTR1 3' region containing rs5182:C>T and rs5186:A>C. Metabolic syndrome trait associations were strongest for the 3' block generally and for the C allele of rs5186:A>C specifically. All effects were much more prominent in homozygotes, possibly reflecting interallelic interaction through feedback loops of mRNA regulation. Differential abundance of AGTR1 mRNA haplotypes may mediate clinical phenotypic observations of the AGTR1 genotype.

Low serine hydroxymethyltransferase activity in the human placenta has important implications for fetal glycine supply.

Glycine is essential for fetal development, but in both sheep and human pregnancy, little is transported directly from the mother to the fetus, indicating that fetal glycine is derived from other sources. In the sheep, placental conversion of maternal serine by serine hydroxymethyltransferase (SHMT) provides almost all the glycine transported to the fetus. Although mRNA for mitochondrial and cytoplasmic SHMT has been detected in human placenta, it is not known whether substantial placental conversion of serine to glycine occurs in species other than sheep. We determined SHMT activity in human, rat, and sheep placenta by measuring conversion of [3-(14)C]serine to (14)C-methylene tetrahydrofolate. Compared with term human placenta, SHMT activity per gram of placenta was 5.1-fold higher in term rat placenta and 24.1-fold higher in term sheep placenta. In sheep placenta, SHMT activity per gram of placenta increased 2.1-fold between mid-gestation and term. In human placenta, placental SHMT activity was similar 8 wk post conception and at term. The low activity of SHMT in the human and rat placenta suggests that, unlike in the sheep, placental conversion of serine to glycine is not a major source of fetal glycine in these species.

Insulin and human chorionic gonadotropin cause a shift in the balance of sterol regulatory element-binding protein (SREBP) isoforms toward the SREBP-1c isoform in cultures of human granulosa cells.

The isoforms of sterol regulatory element-binding proteins (SREBP) (1a, 1c, and 2) are key transcriptional regulators of lipid biosynthesis. We examined their regulation by gonadotropin and insulin in human granulosa cells. After removal of leukocytes, granulosa cells were exposed to hormonal additions for 16 h starting on d 2 of culture. Progesterone, lactate, and IGF binding protein-1 were measured in culture medium and cellular mRNA measured by competitive RT-PCR. Addition of human chorionic gonadotropin (hCG) (100 ng/ml) stimulated progesterone production (7.0-fold, P < 0.001 vs. control), whereas lactate was increased by hCG (1.6-fold, P < 0.001) and insulin (1.4-fold, P < 0.001; 1000 ng/ml). Insulin decreased IGF binding protein-1 production by 85% (P < 0.001). There were no significant effects on the expression of SREBP-1a but significant increases in mRNA for SREBP-1c with insulin (6.3-fold), hCG (10.4-fold) and in combination (15.2-fold; P < 0.01 for all comparisons). No consistent effects on SREBP-2 were observed. The expression of mRNA for fatty acid synthase, a target gene for SREBP-1c, was increased by hCG (24-fold, P = 0.006) and insulin (19-fold, P = 0.024), which also increased the level of cellular, total fatty acid (1.34-fold; P = 0.03). Thus, hCG and insulin cause a switch toward expression of the SREBP-1c isoform with consequent effects on fatty acid synthesis. We suggest that high circulating insulin, associated with clinically defined insulin resistance, may up-regulate SREBP-1c expression in the ovary.

Human embryonic germ cells for future neuronal replacement therapy.

Stem cell therapy offers exciting potential for ambitious cellular replacement to treat human (h) disease, such as Parkinson's disease, Alzheimer's disease or even replacement of the cell death that follows thromboembolic stroke. The realisation of these treatments requires cellular resources possessing three essential characteristics: (i) self-renewal, (ii) the ability to differentiate to physiologically normal cell types and (iii) lack of tumourigenicity. Here, we describe work on human embryonic germ cells (hEGCs), a population of cells alongside human embryonic stem cells (hESCs) with the potential to address these issues.

Metabolic induction and early responses of mouse blastocyst developmental programming following maternal low protein diet affecting life-long health.

Previously, we have shown that a maternal low protein diet, fed exclusively during the preimplantation period of mouse development (Emb-LPD), is sufficient to induce by the blastocyst stage a compensatory growth phenotype in late gestation and postnatally, correlating with increased risk of adult onset cardiovascular disease and behavioural dysfunction. Here, we examine mechanisms of induction of maternal Emb-LPD programming and early compensatory responses by the embryo. Emb-LPD induced changes in maternal serum metabolites at the time of blastocyst formation (E3.5), notably reduced insulin and increased glucose, together with reduced levels of free amino acids (AAs) including branched chain AAs leucine, isoleucine and valine. Emb-LPD also caused reduction in the branched chain AAs within uterine fluid at the blastocyst stage. These maternal changes coincided with an altered content of blastocyst AAs and reduced mTORC1 signalling within blastocysts evident in reduced phosphorylation of effector S6 ribosomal protein and its ratio to total S6 protein but no change in effector 4E-BP1 phosphorylated and total pools. These changes were accompanied by increased proliferation of blastocyst trophectoderm and total cells and subsequent increased spreading of trophoblast cells in blastocyst outgrowths. We propose that induction of metabolic programming following Emb-LPD is achieved through mTORC1signalling which acts as a sensor for preimplantation embryos to detect maternal nutrient levels via branched chain AAs and/or insulin availability. Moreover, this induction step associates with changes in extra-embryonic trophectoderm behaviour occurring as early compensatory responses leading to later nutrient recovery.

The early human germ cell lineage does not express SOX2 during in vivo development or upon in vitro culture.

NANOG, POU5F1, and SOX2 are required by the inner cell mass of the blastocyst and act cooperatively to maintain pluripotency in both mouse and human embryonic stem cells. Inadequacy of any one of them causes loss of the undifferentiated state. Mouse primordial germ cells (PGCs), from which pluripotent embryonic germ cells (EGCs) are derived, also express POU5F1, NANOG, and SOX2. Thus, a similar expression profile has been predicted for human PGCs. Here we show by RT-PCR, immunoblotting, and immunohistochemistry that human PGCs express POU5F1 and NANOG but not SOX2, with no evidence of redundancy within the group B family of human SOX genes. Although lacking SOX2, proliferative human germ cells can still be identified in situ during early development and are capable of culture in vitro. Surprisingly, with the exception of FGF4, many stem cell-restricted SOX2 target genes remained detected within the human SOX2-negative germ cell lineage. These studies demonstrate an unexpected difference in gene expression between human and mouse. The human PGC is the first primary cell type described to express POU5F1 and NANOG but not SOX2. The data also provide a new reference point for studies attempting to turn human stem cells into gametes by normal developmental pathways for the treatment of infertility.

Human embryos developing in vitro are susceptible to impaired epithelial junction biogenesis correlating with abnormal metabolic activity.

BACKGROUND: Blastocyst biogenesis occurs over several cell cycles during the preimplantation period comprising the gradual expression and membrane assembly of junctional protein complexes which distinguish the outer epithelial trophectoderm (TE) cells from the inner cell mass (ICM). In the human, TE integrity and the formation of a junctional seal can often be impaired. Embryos likely to result in a successful pregnancy after transfer are mostly selected according to morphological criteria. Recent data suggest that non-invasive measurement of amino acid turnover may be useful to complement such morphological scores. Whether morphological and metabolic criteria can be linked to poor TE differentiation thereby underpinning developmental predictions mechanistically remains unknown. METHODS: We examined TE intercellular junction formation in human embryos by immunofluorescence and confocal microscopy and correlated this process with morphological criteria and amino acid turnover during late cleavage. RESULTS: Our results show that TE differentiation may be compromised by failure of membrane assembly of specific junction constituents. This abnormality relates more closely to metabolic profiles than morphological criteria. CONCLUSION: Our data identify that amino acid turnover can predict TE differentiation. These findings are the first to link two mechanisms, metabolism and junction membrane assembly, which contribute to early embryo development.

Evaluating human embryonic germ cells: concord and conflict as pluripotent stem cells.

The realization of cell replacement therapy derived from human pluripotent stem cells requires full knowledge of the starting cell types as well as their differentiated progeny. Alongside embryonic stem cells, embryonic germ cells (EGCs) are an alternative source of pluripotent stem cell. Since 1998, four groups have described the derivation of human EGCs. This review analyzes the progress on derivation, culture, and differentiation, drawing comparison with other pluripotent stem cell populations.

Relative contribution of cell contact pattern, specific PKC isoforms and gap junctional communication in tight junction assembly in the mouse early embryo.

In mouse early development, cell contact patterns regulate the spatial organization and segregation of inner cell mass (ICM) and trophectoderm epithelium (TE) during blastocyst morphogenesis. Progressive membrane assembly of tight junctional (TJ) proteins in the differentiating TE during cleavage is upregulated by cell contact asymmetry (outside position) and suppressed within the ICM by cell contact symmetry (inside position). This is reversible, and immunosurgical isolation of the ICM induces upregulation of TJ assembly in a sequence that broadly mimics that occurring during blastocyst formation. The mechanism relating cell contact pattern and TJ assembly was investigated in the ICM model with respect to PKC-mediated signaling and gap junctional communication. Our results indicate that complete cell contact asymmetry is required for TJ biogenesis and acts upstream of PKC-mediated signaling. Specific inhibition of two PKC isoforms, PKCdelta and zeta, revealed that both PKC activities are required for membrane assembly of ZO-2 TJ protein, while only PKCzeta activity is involved in regulating ZO-1alpha+ membrane assembly, suggesting different mechanisms for individual TJ proteins. Gap junctional communication had no apparent influence on either TJ formation or PKC signaling but was itself affected by changes of cell contact patterns. Our data suggest that the dynamics of cell contact patterns coordinate the spatial organization of TJ formation via specific PKC signaling pathways during blastocyst biogenesis.

The Mirena levonorgestrel system.

The levonorgestrel intrauterine system is a safe, efficacious, long-term contraceptive device. Additionally, it results in a decrease in the volume of menstrual blood loss in women with normal periods and those with menorrhagia. It may also have a role in the treatment of other benign gynecological disorders, such as adenomyosis or endometriosis, and it has been advocated as a means of delivering progestogen to the endometrium as part of combined hormone replacement therapy. Despite the beneficial effect on menstrual volume, compliance is sometimes limited by breakthrough bleeding during the first months of use. The precise mechanism of this bleeding is unclear, but it may be related to a direct effect of levonorgestrel on endometrial vascular development. Detailed counseling is crucial to explain this anticipated side effect in order to reduce unnecessary discontinuation of treatment.