The endocrinology of menstruation--a role for the immune system

Relationships between biomarkers of inflammation, ovarian steroids, and age at menarche in a rural Polish sample

OBJECTIVES

To test the hypothesis that life history trade-offs between maintenance and reproductive effort would be evident through inverse associations between levels of a biomarker of inflammation [C-reactive protein (CRP)], and ovarian hormones. Associations between CRP and age at menarche were also explored.

METHODS

Urinary CRP, salivary progesterone, and estradiol were measured over one menstrual cycle from rural Polish women (n = 25), representing a natural fertility sample. Age of menarche was assessed through interview recall methods. We used minimum second-order Akaike Information Criteria as a means of multiple regression model selection, and repeated measures ANOVA to test cycle-dependent hypotheses.

RESULTS

Comparisons of individuals in high and low CRP tertiles revealed that those with high CRP had significantly lower progesterone (luteal P = 0.03, mid luteal P = 0.007) but not estradiol (follicular P = 0.21, luteal P = 0.15) concentrations through the menstrual cycle. However, when the age at menarche was included in the analysis, both age at menarche and urinary CRP were negatively associated with estradiol (R(2) = 0.44, P = 0.0007). Age at menarche and estradiol were the strongest negative predictors of CRP (R(2) = 0.52, P = 0.0001).

CONCLUSIONS

Inflammation itself may suppress ovarian function, or indicate immune challenges that lead to ovarian suppression. The timing of menarche may also influence adult inflammatory sensitivity and ovarian hormone concentrations. This lends support to existing models of trade-offs between maintenance and reproduction in women.

Immunology of normal and abnormal menstruation

Normal menstruation is an inflammatory process, where the endometrial concentrations and functions of several leukocyte types can change greatly through the menstrual cycle, especially during the premenstrual and menstrual phases. These leukocytes probably have a range of functions related to mucosal protection, decidualization, embryo implantation, and the process of menstrual tissue breakdown, repair and remodeling. Some of these leukocyte changes are apparently linked to changes in the pattern of circulating leukocytes. Many immune cells have been identified in the endometrium, and those with most relevance to the processes of menstruation include uterine natural killer cells, macrophages, mast cells, neutrophils, dendritic cells and Tregs. A range of disturbances in endometrial immune cell numbers, distributions and functions, and in a range of different inflammatory and other mediators, have been identified in women with heavy menstrual bleeding or endometriosis. Sufficient evidence exists to implicate these immune changes in some of the functional disturbances and symptoms identified in these women. This field is greatly under-researched, and ripe for the wider application of modern molecular and cellular techniques in human and animal model studies.

Cyclooxygenase-2 regulated by the nuclear factor-κB pathway plays an important role in endometrial breakdown in a female mouse menstrual-like model

The role of prostaglandins (PGs) in menstruation has long been proposed. Although evidence from studies on human and nonhuman primates supports the involvement of PGs in menstruation, whether PGs play an obligatory role in the process remains unclear. Although cyclooxygenase (COX) inhibitors have been used in the treatment of irregular uterine bleeding, the mechanism involved has not been elucidated. In this study, we used a recently established mouse menstrual-like model for investigating the role of COX in endometrial breakdown and its regulation. Administration of the nonspecific COX inhibitor indomethacin and the COX-2 selective inhibitor DuP-697 led to inhibition of the menstrual-like process. Furthermore, immunostaining analysis showed that the nuclear factor (NF)κB proteins P50, P65, and COX-2 colocalized in the outer decidual stroma at 12 to 16 hours after progesterone withdrawal. Chromatin immunoprecipitation analysis showed that NFκB binding to the Cox-2 promoter increased at 12 hours after progesterone withdrawal in vivo, and real-time PCR analysis showed that the NFκB inhibitors pyrrolidine dithiocarbamate and MG-132 inhibited Cox-2 mRNA expression in vivo and in vitro, respectively. Furthermore, COX-2 and NFκB inhibitors similarly reduced endometrial breakdown, suggesting that NFκB/COX-2-derived PGs play a critical role in this process. In addition, the CD45(+) leukocyte numbers were sharply reduced following indomethacin (COX-1 and COX-2 inhibitor), DuP-697 (COX-2 inhibitor), and pyrrolidine dithiocarbamate (NFκB inhibitor) treatment. Collectively, these data indicate that NFκB/COX-2-induced PGs regulate leukocyte influx, leading to endometrial breakdown.

The motile and invasive capacity of human endometrial stromal cells: implications for normal and impaired reproductive function

BACKGROUND Mechanisms underlying early reproductive loss in the human are beginning to be elucidated. The migratory and invasive capacity of human endometrial stromal cells (ESCs) is increasingly recognized to contribute to the intense tissue remodelling associated with embryo implantation, trophoblast invasion and endometrial regeneration. In this review, we examine the signals and mechanisms that control ESC migration and invasion and assess how deregulation of these cell functions contributes to common reproductive disorders. METHODS The PubMed database was searched for publications on motility and invasiveness of human ESCs in normal endometrial function and in reproductive disorders including implantation failure, recurrent pregnancy loss (RPL), endometriosis and adenomyosis, covering the period 2000-2012. RESULTS Increasing evidence suggests that implantation failure and RPL involve abnormal migratory responses of decidualizing ESCs to embryo and trophoblast signals. Numerous reports indicate that endometriosis, as well as adenomyosis, is associated with increased basal and stimulated invasiveness of ESCs and their progenitor cells, suggesting a link between a heightened menstrual repair response and the formation of ectopic implants. Migration and invasiveness of ESCs are controlled by a complex array of hormones, growth factors, chemokines and inflammatory mediators, and involve signalling through Rho GTPases, phosphatidylinositol-3-kinase and mitogen-activated protein kinase pathways. CONCLUSIONS Novel concepts are extending our understanding of the key functions of ESCs in effecting tissue repair imposed by cyclic menstruation and parturition. Migration of decidualizing ESCs also serves to support blastocyst implantation and embryo selection through discriminate motile responses directed by embryo quality. Targeting regulatory molecules holds promise for developing new strategies for the treatment of reproductive disorders such as endometriosis and recurrent miscarriage; and harnessing the migratory capacity of progenitor mesenchymal stem cells in the endometrium may offer new opportunities in regenerative medicine.

Regulation of innate immune function in bovine oviduct epithelial cells in culture: the homeostatic role of epithelial cells in balancing Th1/Th2 response

This study aimed to investigate the role of epithelial cells in regulating innate immunity in bovine oviduct epithelial cell (BOEC) culture. We studied the effect of Escherichia coli lipopolysaccharide (LPS) and its interaction with ovarian steroids, estradiol (E2) and progesterone (P4), and luteinizing hormone (LH) at concentrations observed during the preovulatory period on immune responses in BOEC culture. Immunohistochemistry of oviduct tissue showed intensive expression of Toll-like receptor-4 (TLR-4) and TLR-2 in epithelial cells. A dose of 10 ng/ml LPS stimulated TLR-4, cyclooxygenase-2 (COX-2), nuclear factor kappa B inhibitor A (NFKBIA), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) expression, indicating an early pro-inflammatory response. A dose of 100 ng/ml LPS did not induce expression of these genes but stimulated TLR-2, IL-10,IL-4 and microsomal prostaglandin E synthase-1 (mPGES-1) expression and PGE2 secretion, indicating an anti-inflammatory response. Ovarian steroids and LH completely block LPS (10 ng/ml)-induced TLR-4, IL-1β and TNF-α expression as well as LPS (100 ng/ml)-induced TLR-2 expression. Taken together, this study suggests the existence of an early signaling system to respond to infection in the BOEC. In addition, ovarian steroids and LH may play a critical role in inducing homeostasis and in controlling hyperactive pro-inflammatory responses detrimental to epithelial cells, sperm and the embryo.

The importance of the macrophage within the human endometrium

The human endometrium is exposed to cyclical fluctuations of ovarian-derived sex steroids resulting in proliferation, differentiation (decidualization), and menstruation. An influx of leukocytes (up to 15% macrophages) occurs during the latter stages of the menstrual cycle, including menses. We believe the endometrial macrophage is likely to play an important role during the menstrual cycle, especially in the context of tissue degradation (menstruation), which requires regulated repair, regeneration, and phagocytic clearance of endometrial tissue debris to re-establish tissue integrity in preparation for fertility. The phenotype and regulation of the macrophage within the endometrium during the menstrual cycle and interactions with other cell types that constitute the endometrium are currently unknown and are important areas of study. Understanding the many roles of the endometrial macrophage is crucial to our body of knowledge concerning functionality of the endometrium as well as to our understanding of disorders of the menstrual cycle, which have major impacts on the health and well-being of women.

Anatomy of female puberty: The clinical relevance of developmental changes in the reproductive system

Puberty is the period of biologic transition from childhood to adulthood. The changes that occur at this time are related to the increasing concentrations of sex steroid hormones. In females, most pubertal changes are caused by estrogen stimulation that results from the onset of central puberty. Significant development occurs in the organs of the female reproductive system and results in anatomic changes that characterize reproductive maturity. Adrenal and ovarian androgens also increase during puberty, affecting change that includes the promotion of certain secondary sex characteristics. The ability to recognize normal pubertal anatomy and distinguish between estrogen and androgen effects is important in the ability to diagnose and treat disorders of sex development, precocious puberty, pubertal delay, and menstrual irregularities in children and adolescents. An understanding of this developmental process can also help clinicians identify and treat reproductive pathology in adults and across all female life stages.

ATP and ADP hydrolysis in cell membranes from rat myometrium

Extracellular nucleotides affect female reproductive functions, fertilization, and pregnancy. The aim of this study was to investigate biochemical characteristics of ATP and ADP hydrolysis and identify E-NTPDases in myometrial cell membranes from Wistar albino rats. The apparent K (m) values were 506.4 ± 62.1 and 638.8 ± 31.3 μM, with a calculated V (max) (app) of 3,973.0 ± 279.5 and 2,853.9 ± 79.8 nmol/min/mg for ATP and ADP, respectively. The enzyme activity described here has common properties characteristic for NTPDases: divalent cation dependence; alkaline pH optimum for both substrates, insensitivity to some of classical ATPase inhibitors (ouabain, oligomycine, theophylline, levamisole) and significant inhibition by suramine and high concentration of sodium azides (5 mM). According to similar apparent K(m) values for both substrates, the ATP/ADP hydrolysis ratio, and Chevillard competition plot, NTPDase1 is dominant ATP/ADP hydrolyzing enzyme in myometrial cell membranes. RT-PCR analysis revealed expression of three members of ectonucleoside triphosphate diphosphohydrolase family (NTPDase 1, 2, and 8) in rat uterus. These findings may further elucidate the role of NTPDases and ATP in reproductive physiology.

Recurrent menstrual toxic shock syndrome despite discontinuation of tampon use: is menstrual toxic shock syndrome really caused by tampons?

Menstrual toxic shock syndrome (MTSS) is a rare and potentially life-threatening illness. We present a case of recurrent MTSS initially associated with tampon use that continued to recur when tampons were discontinued, which was successfully treated with rifampicin and clindamycin.

The genomics of the human endometrium

The endometrium is a complex tissue that lines the inside of the endometrial cavity. The gene expression of the different endometrial cell types is regulated by ovarian steroids and paracrine-secreted molecules from neighbouring cells. Due to this regulation, the endometrium goes through cyclic modifications which can be divided simply into the proliferative phase, the secretory phase and the menstrual phase. Successful embryo implantation depends on three factors: embryo quality, the endometrium's state of receptivity, and a synchronised dialogue between the maternal tissue and the blastocyst. There is a need to characterise the endometrium's state of receptivity in order to prevent reproductive failure. No single molecular or histological marker for this status has yet been found. Here, we review the global transcriptomic analyses performed in the last decade on a normal human endometrium. These studies provide us with a clue about what global gene expression can be expected for a non-pathological endometrium. These studies have shown endometrial phase-specific transcriptomic profiles and common temporal gene expression patterns. We summarise the biological processes and genes regulated in the different phases of natural cycles and present other works on different conditions as well as a receptivity diagnostic tool based on a specific gene set profile. This article is part of a Special Issue entitled: Molecular Genetics of Human Reproductive Failure.

The nuclear factor-κB pathway is involved in matrix metalloproteinase-9 expression in RU486-induced endometrium breakdown in mice

BACKGROUND

Progesterone-withdrawal (WP)-induced endometrial breakdown occurs in both physiological and pathological processes such as menstruation and abortion. However, the underlying mechanisms are not clearly understood. As the nuclear factor-κB (NF-κB) pathway has been proposed to play a role in endometrial breakdown, we tested this hypothesis using RU486-induced mouse menstruation-like model.

METHODS

The activation of NF-κB was evaluated by immunohistochemistry, western blot and immunofluorescence. The expression of matrix metalloproteinase-9 (MMP9) was analyzed by real-time PCR and its proteins by gelatin zymography and western blot. Chromatin immunoprecipitation was used to investigate the direct binding of NF-κB to MMP9 gene promoter. Inhibitors of NF-κB were used to block its signal in vivo and in vitro to analyze the function of NF-κB in the tissue breakdown process.

RESULTS

Administration of RU486 resulted in increased phospho-IκB levels and nuclear translocation of p65 in decidual stromal cells, accompanied by the up-regulation of NF-κB inducing kinase and IκB kinase β mRNA. The NF-κB inhibitor, 'pyrrolidine dithiocarbamate' partially suppressed the RU486-induced endometrial breakdown, thus verifying the role of this pathway in vivo. MMP9 was up- and down-regulated following the NF-κB activation and inhibition, respectively. RU486 stimulated recruitment of NF-κB p65 to the MMP9 promoter and further increased its expression. Effects of NF-κB activation and inactivation on MMP9 expression were further explored in human stromal cells in vitro. A similar MMP9 expression pattern was observed in cultured human, as well as mouse, decidual stromal cells following RU486 treatment.

CONCLUSIONS

The activation of the NF-κB pathway induces downstream target genes, including MMP9 from stromal cells to facilitate tissue breakdown in mouse uterus, highlighting the likelihood that this regulatory pattern exists in the human endometrium.

Genetic and environmental determinants of menstrual characteristics

BACKGROUND

The impact of women's menstrual cycle on her quality of life, health, work, and community is substantial. Menstrual disturbance is linked with general ill conditions such as migraine, asthma, and endocrinopathies. The clinical significance of medical interventions to prevent these conditions becomes clear if the role of genetic or environment is clarified.

AIMS

To identify the genetic and environmental contribution on menstrual characteristics.

SETTING AND DESIGN

This was a cross-sectional study in 2 Asian countries.

MATERIALS AND METHODS

2 cohorts of monozygotic and dizygotic twins born between (1945-1988, n = 122) and (1951-1993, n = 71) were taken. A standard questionnaire was designed inclusive of socio- demographic characteristics of subjects as well as menstrual history (duration, interval, amount, irregularity). Subjects were interviewed by phone.

STATISTICAL ANALYSIS

Quantitative variables were analyzed using Falconars' formula as well as maximum likelihood analysis. Structural modeling was then applied to twin correlations to provide estimates of the relative genetic and/or environmental factors contribution in determining the measured trait.

RESULTS

Menstrual characteristics were found to be under environmental influence where the best fitting model for menstrual interval and duration was common environment. CDF plotting confirmed the results for both variables. Proband-wise concordance analysis for amount of menstruation, amenorrhea, and irregular menstruation revealed no genetic influence. The best fitting model for menstrual irregularity was CE (C73%, E27%). The same model was defined for amenorrhea (C48%, E52%).

CONCLUSIONS

Environmental factors are most likely responsible to determine the menstrual flow, its integrity, and regularity. These factors need to be studied further.

The presence and regulation of connective tissue growth factor in the human endometrium

BACKGROUND

The human endometrium efficiently repairs each month after menstruation. The mechanisms involved in this repair process remain undefined. Aberrations in endometrial repair may lead to the common disorder of heavy menstrual bleeding. We hypothesized that connective tissue growth factor (CTGF) is increased at the time of endometrial repair post-menses and that this increase is regulated by prostaglandins (PGs) and hypoxic conditions present during menstruation.

METHODS AND RESULTS

Examination of 41 endometrial biopsies from 5 stages of the menstrual cycle revealed maximal CTGF mRNA expression (using quantitative RT-PCR) at menstruation and peak protein levels during the proliferative phase. CTGF was immunolocalized to epithelial and stromal cells, with intense staining of occasional stromal cells during the proliferative phase. Dual immunohistochemistry identified these cells as macrophages. Treatment of endometrial epithelial cells with 100 nM PGE(2), PGF(2α) or hypoxia (0.5% O(2)) revealed a significant increase in CTGF mRNA expression (P < 0.01 for all, versus vehicle control). Cells treated simultaneously with PGE(2) and hypoxia revealed a synergistic increase in CTGF expression (P < 0.05 versus PGE(2) or hypoxia alone) and maximal secreted CTGF protein levels (P < 0.05 versus control).

CONCLUSIONS

CTGF is increased in the human endometrium at the time of endometrial repair post-menses. The increase in CTGF may be mediated by PG production and the transient hypoxic episode observed in the endometrium at menstruation.

Induction of overt menstruation in intact mice

The complex tissue remodeling process of menstruation is experienced by humans and some primates, whereas most placental mammals, including mice, go through an estrous cycle. How menstruation and the underlying mechanisms evolved is still unknown. Here we demonstrate that the process of menstruation is not just species-specific but also depends on factors which can be induced experimentally. In intact female mice endogenous progesterone levels were raised by the induction of pseudopregnancy. Following an intrauterine oil injection, the decidualization of the endometrium was reliably induced as a prerequisite for menstruation. The natural drop of endogenous progesterone led to spontaneous breakdown of endometrial tissue within an average of 3 days post induction of decidualization. Interestingly, morphological changes such as breakdown and repair of the endometrial layer occurred in parallel in the same uterine horn. Most importantly, endometrial breakdown was accompanied by vaginally visible (overt) bleeding and flushing out of shed tissue comparable to human menstruation. Real-time PCR data clearly showed temporal changes in the expression of multiple factors participating in inflammation, angiogenesis, tissue modulation, proliferation, and apoptosis, as has been described for human menstruating endometrium. In conclusion, human menstruation can be mimicked in terms of extravaginally visible bleeding, tissue remodeling, and gene regulation in naturally non-menstruating species such as intact female mice without the need for an exogenous hormone supply.

Endogenous reproductive hormones and C-reactive protein across the menstrual cycle: the BioCycle Study

C-reactive protein (CRP) is one of the most commonly used markers of acute phase reaction in clinical settings and predictors of cardiovascular risk in healthy women; however, data on its physiologic regulation in premenopausal women are sparse. The objective of this study was to evaluate the association between endogenous reproductive hormones and CRP in the BioCycle Study (2005-2007). Women aged 18-44 years from western New York were followed prospectively for up to 2 menstrual cycles (n = 259). Serum levels of CRP, estradiol, progesterone, luteinizing hormone, and follicle-stimulating hormone were measured up to 8 times per cycle, timed by fertility monitors. CRP levels varied significantly across the cycle (P < 0.001). More women were classified as being at elevated risk of cardiovascular disease (CRP, >3 mg/L) during menses compared with other phases (12.3% vs. 7.4%; P < 0.001). A 10-fold increase in estradiol was associated with a 24.3% decrease in CRP (95% confidence interval: 19.3, 29.0). A 10-fold increase in luteal progesterone was associated with a 19.4% increase in CRP (95% confidence interval: 8.4, 31.5). These results support the hypothesis that endogenous estradiol might have antiinflammatory effects and highlight the need for standardization of CRP measurement to menstrual cycle phase in reproductive-aged women.

AUF1/hnRNP D represses expression of VEGF in macrophages

Vascular endothelial growth factor (VEGF) expression is regulated by sequence elements in the 3′ UTR of VEGF mRNA. AUF1/hnRNP D suppresses VEGF 3′ UTR–dependent expression. Peptides with arginine–glycine–glycine motifs derived from AUF1 also suppress VEGF expression.

Vascular endothelial growth factor (VEGF) is a regulator of vascularization in development and is a key growth factor in tissue repair. In disease, VEGF contributes to vascularization of solid tumors and arthritic joints. This study examines the role of the mRNA-binding protein AUF1/heterogeneous nuclear ribonucleoprotein D (AUF1) in VEGF gene expression. We show that overexpression of AUF1 in mouse macrophage-like RAW-264.7 cells suppresses endogenous VEGF protein levels. To study 3′ untranslated region (UTR)–mediated regulation, we introduced the 3′ UTR of VEGF mRNA into a luciferase reporter gene. Coexpression of AUF1 represses VEGF-3′ UTR reporter expression in RAW-264.7 cells and in mouse bone marrow–derived macrophages. The C-terminus of AUF1 contains arginine–glycine–glycine (RGG) repeat motifs that are dimethylated. Deletion of the RGG domain of AUF1 eliminated the repressive effects of AUF1. Surprisingly, expression of an AUF1-RGG peptide reduced endogenous VEGF protein levels and repressed VEGF-3′ UTR reporter activity in RAW-264.7 cells. These findings demonstrate that AUF1 regulates VEGF expression, and this study identifies an RGG peptide that suppresses VEGF gene expression.

Hormonal regulation of uterine chemokines and immune cells

The ultimate function of the endometrium is to allow the implantation of a blastocyst and to support pregnancy. Cycles of tissue remodeling ensure that the endometrium is in a receptive state during the putative 'implantation window', the few days of each menstrual cycle when an appropriately developed blastocyst may be available to implant in the uterus. A successful pregnancy requires strict temporal regulation of maternal immune function to accommodate a semi-allogeneic embryo. To preparing immunological tolerance at the onset of implantation, tight temporal regulations are required between the immune and endocrine networks. This review will discuss about the action of steroid hormones on the human endometrium and particularly their role in regulating the inflammatory processes associated with endometrial receptivity.

Immune interactions in endometriosis

Endometriosis is a common, complex gynecologic disorder characterized by the presence of endometrial glands and stroma at extrauterine (ectopic) sites. In women who develop this disease, alterations in specific biological processes involving both the endocrine and immune systems have been observed, which may explain the survival and growth of displaced endometrial tissue in affected women. In the past decade, a considerable amount of research has implicated a role for alterations in progesterone action at both eutopic and ectopic sites of endometrial growth which may contribute to the excessive inflammation associated with progression of endometriosis; however, it remains unclear whether these anomalies induce the condition or are simply a consequence of the disease process. In this article, we summarize current knowledge of alterations within the immune system of endometriosis patients and discuss how endometrial cells from women with this disease not only have the capacity to escape immunosurveillance, but also use inflammatory mechanisms to promote their growth within the peritoneal cavity. Finally, we discuss evidence that exposure to an environmental endocrine disruptor, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin, can mediate the development of an endometrial phenotype that exhibits both reduced progesterone responsiveness and hypersensitivity to proinflammatory stimuli mimicking the endometriosis phenotype. Future studies in women with endometriosis should consider whether a heightened inflammatory response within the peritoneal microenvironment contributes to the development and persistence of this disease.

Progesterone: a pivotal hormone at menstruation

The human endometrium is exposed to repeated inflammation every month, culminating in tissue breakdown and menstruation. Subsequently, the endometrium has a remarkable capacity for efficient repair and remodeling to enable implantation if fertilization takes place. Endometrial function is known to be governed by the ovarian hormones estradiol and progesterone. This review paper focuses on hormonal control of the cyclical tissue injury and repair that takes place in the local endometrial environment at the time of menstruation. Progesterone levels decline premenstrually as the corpus luteum regresses in the absence of pregnancy, and estradiol levels increase during the postmenstrual phase. The functional impact of these significant changes is discussed, including their immediate and downstream effects. Finally, we examine the contribution of aberrant endometrial function to the presentation of heavy menstrual bleeding and identify potential therapeutic targets for the treatment of this common gynecological problem.

Lymphoid and myeloid cell populations in the non-pregnant human Fallopian tube and in ectopic pregnancy

Lymphoid and myeloid cell populations in human endometrium are well-documented and are known to play important roles in providing immune tolerance, controlling trophoblast invasion, and mediating vascular remodeling. Immune cell populations in the Fallopian tube have not been comprehensively studied. The aim of this study was to characterize lymphoid and myeloid cell populations in non-pregnant Fallopian tube and determine whether they are altered in Fallopian tube from women with ectopic pregnancy. Fallopian tube was analyzed by flow cytometry and immunohistochemistry. Populations of CD3+ (CD4+ and CD8+) lymphocytes, LIN1-HLADR+ (CD123+ and CD11c+) dendritic cells, monocytes, neutrophils, and CD56(dim)CD16- natural killer (NK) cells were demonstrated to be present in non-pregnant Fallopian tube. CD123+ dendritic cells were predominant over CD11c+ dendritic cells. Numbers of CD11c+ cells were significantly higher in the progesterone-dominant mid-luteal phase of the menstrual cycle compared with the follicular phase. Numbers of CD45+ leukocytes, CD68+ cells, and CD11c+ cells were higher in Fallopian tube from women with ectopic pregnancy compared with mid-luteal phase Fallopian tube. These data will advance our understanding of normal human Fallopian tube physiology and disorders of Fallopian tube function, such as ectopic pregnancy.

Is cortisol excretion independent of menstrual cycle day? A longitudinal evaluation of first morning urinary specimens

Background

Cortisol is frequently used as a marker of physiologic stress levels. Using cortisol for that purpose, however, requires a thorough understanding of its normal longitudinal variability. The current understanding of longitudinal variability of basal cortisol secretion in women is very limited. It is often assumed, for example, that basal cortisol profiles do not vary across the menstrual cycle. This is a critical assumption: if cortisol were to follow a time dependent pattern during the menstrual cycle, then ignoring this cyclic variation could lead to erroneous imputation of physiologic stress. Yet, the assumption that basal cortisol levels are stable across the menstrual cycle rests on partial and contradictory evidence. Here we conduct a thorough test of that assumption using data collected for up to a year from 25 women living in rural Guatemala.

Methodology

We apply a linear mixed model to describe longitudinal first morning urinary cortisol profiles, accounting for differences in both mean and standard deviation of cortisol among women. To that aim we evaluate the fit of two alternative models. The first model assumes that cortisol does not vary with menstrual cycle day. The second assumes that cortisol mean varies across the menstrual cycle. Menstrual cycles are aligned on ovulation day (day 0). Follicular days are assigned negative numbers and luteal days positive numbers. When we compared Models 1 and 2 restricting our analysis to days between −14 (follicular) and day 14 (luteal) then day of the menstrual cycle did not emerge as a predictor of urinary cortisol levels (p-value >0.05). Yet, when we extended our analyses beyond that central 28-day-period then day of the menstrual cycle become a statistically significant predictor of cortisol levels.

Significance

The observed trend suggests that studies including cycling women should account for day dependent variation in cortisol in cycles with long follicular and luteal phases.

Inflammatory pathways in endometrial disorders

Complex interactions between the endocrine and immune systems govern the key endometrial events of implantation and menstruation. In contrast to other tissue sites, cyclical endometrial inflammation is physiological. However, dysregulation of this inflammatory response can lead to endometrial disorders. This review examines the inflammatory processes occurring in the normal endometrium during menstruation and implantation, highlighting recent advances in our understanding and gaps in current knowledge. Subsequently, the role of inflammatory pathways in the pathology of various common endometrial conditions is discussed, including heavy menstrual bleeding, dysmenorrhoea (painful periods), uterine fibroids, endometriosis and recurrent miscarriage.

Divergent mechanisms for trophic actions of estrogens in the brain and peripheral tissues

17β-estradiol (E(2)) can enhance reproductive, cognitive, and affective functions; however, the mechanisms by which E(2) has these effects need to be better understood. Pleiotrophic effects of E(2) can occur via traditional and novel actions at various forms of estrogen receptors (ERs). In the central nervous system, trophic effects of E(2) may be related to beneficial effects of hormone replacement therapy (HRT). However, in peripheral reproductive tissues, E(2)'s capacity to evoke growth can increase risk of cancers. This review focuses on investigations aimed at elucidating divergent mechanisms of steroids to promote trophic effects in the brain, independent of effects on peripheral reproductive tissues. First, actions of estrogens via ERα or ERβ for peripheral growth (carcinogen-induced tumors, uterine growth) and hippocampus-dependent behaviors (affect, cognition) are described. Second, factors that influence these effects of estrogens are described (e.g. experience, timing/critical windows, non-ER mechanisms). Third, effects of estrogens at ERβ related to actions of progestogens, such as 5α-pregnan-3α-ol-20-one (3α,5α-THP) are described. In summary, effects of E(2) may occur via multiple mechanisms, which may underlie favorable effects in the brain with minimal peripheral trophic effects.

Chronic pelvic pain and endometriosis: translational evidence of the relationship and implications

BACKGROUND

Many clinicians and patients believe that endometriosis-associated pain is due to the lesions. Yet causality remains an enigma, because pain symptoms attributed to endometriosis occur in women without endometriosis and because pain symptoms and severity correlate poorly with lesion characteristics. Most research and reviews focus on the lesions, not the pain. This review starts with the recognition that the experience of pain is determined by the central nervous system (CNS) and focuses on the pain symptoms.

METHODS

Comprehensive searches of Pubmed, Medline and Embase were conducted for current basic and clinical research on chronic pelvic pain and endometriosis. The information was mutually interpreted by a basic scientist and a clinical researcher, both in the field of endometriosis. The goal was to develop new ways to conceptualize how endometriosis contributes to pain symptoms in the context of current treatments and the reproductive tract.

RESULTS

Endometriotic lesions can develop their own nerve supply, thereby creating a direct and two-way interaction between lesions and the CNS. This engagement provides a mechanism by which the dynamic and hormonally responsive nervous system is brought directly into play to produce a variety of individual differences in pain that can, in some women, become independent of the disease itself.

CONCLUSIONS

Major advances in improving understanding and alleviating pain in endometriosis will likely occur if the focus changes from lesions to pain. In turn, how endometriosis affects the CNS would be best examined in the context of mechanisms underlying other chronic pain conditions.

Oestrogen and progesterone regulation of inflammatory processes in the human endometrium

The human endometrium is a unique tissue that has to undergo cycles of proliferation, differentiation, destruction and repair. This ensures that the endometrium is optimally prepared for potential embryo implantation but in the absence of an embryo, menstruation occurs to allow endometrial regeneration. These cycles of tissue remodelling occur under the sequential influence of the sex steroid hormones, oestrogen and progesterone. The physiological events of implantation and menstruation display features of inflammation, tightly regulated by oestrogen and progesterone. After menstruation cellular proliferation and blood vessel growth is modulated by oestrogen while after ovulation progesterone is the dominant hormone. In preparation for implantation, progesterone regulates decidualization of the endometrium, uterine natural killer cell numbers within the endometrium and chemokine and cytokine expression. Menstruation, in contrast, is preceded by progesterone withdrawal, which results in an influx of leukocytes into the endometrium and increased production of chemokines and matrix metalloproteinases allowing tissue degradation. The aim of this article is to review the current knowledge on the regulation of inflammatory events within the endometrium by oestrogen and progesterone, in relation to two pivotal events for human reproduction, implantation and menstruation.

Perimenstrual increase in bronchial hyperreactivity in premenopausal women: results from the population-based SAPALDIA 2 cohort

BACKGROUND

Studies on perimenstrual asthma are inconsistent, and different methodologies limit comparisons.

OBJECTIVE

To investigate cyclic variations in bronchial hyperreactivity (BHR) to methacholine in premenopausal women in a population-based cohort and assess effect modification by oral contraceptives (OCs).

METHODS

Day of menstruation cycle at the time of methacholine challenge was calculated in 571 menstruating women without hormonal treatment, age 28 to 58 years, on the basis of questionnaire data from the Swiss cohort study on Air Pollution And Lung Disease In Adults (SAPALDIA) cohort 2001/2002. A window of risk was defined 3 days before and after the first day of menstruation. Logistic and linear regression analyses were performed adjusting for main predictors of BHR and stratifying for asthma status. The impact of OCs was studied in the same sample enlarged by 130 women taking OCs.

RESULTS

The prevalence of BHR was 13% (fall of > or =20% in FEV(1) up to a maximal cumulative dose of 2 mg), and 6% had asthma. A total of 143 women had undergone methacholine challenge within the risk window. We observed a significant increase in BHR within the window of risk (odds ratio [OR], 2.3; 95% CI, 1.27-4.29). A cyclic association pattern was confirmed by trigonometric functions. Effect modification by asthma status and oral contraceptive use was found, with lower OR in subjects without asthma and OR <1 in women using OCs.

CONCLUSION

The data provide evidence of a systematic variation in BHR during the menstruation cycle, supporting the hypothesis of a hormonal influence. OCs appear to have a protective effect. Cyclicity of BHR could be of clinical importance in view of future medication recommendations and timing of respiratory function tests in women.

Endometrial cytology and computerized morphometric analysis of epithelial nuclei: a useful tool for reproductive diagnosis in the bitch

New diagnostic approaches are required to recognize early canine hypofertility or infertility. We suggest that the identification of different cytologic types, cellular aspects, and nuclear features of the endometrial epithelial cells may be suitable for this purpose. This study was performed on the bitch (Canis familiaris) during the physiologic reproductive cycle and in uterine diseases. We also applied computerized cytomorphometry to evaluate nuclear area, perimeter, diameter, density, aspect, and roundness of endometrial epithelial cells in healthy dogs (N=35) at different stages of the reproductive cycle (before puberty, during proestrus, estrus, diestrus, and anestrus) and in bitches affected by uterine disorders (N=10). The stage of the estrous cycle was determined by vaginal cytology and progesterone evaluation and also confirmed by clinical and histologic observations. Samples for endometrial cytology were collected in vivo by uterine flushing with transcervical uterine cannulation. After uterine sampling, each dog underwent OHE or uterine stump revision. Cytologic analyses were compared with histologic examinations to verify the uterine condition. The uterine cellular population was represented by endometrial epithelial cells, erythrocytes, neutrophils, lymphocytes, eosinophils, macrophages, plasma cells, and cervical or incidental vaginal cells. Bacteria and amorphous material were observed. The proportion of different cells and nuclear features in the cytologic samples varied throughout the stages of the reproductive cycle and between normal and pathologic uterine conditions. The computer-assisted nuclear morphometry, performed in cytologic specimens by means of the six nuclear parameters chosen to evaluate the endometrial epithelial cell population, proved to be useful for determining the stage of the reproductive cycle. Furthermore, this system was demonstrated to be a valid support to diagnose and distinguish uterine disorders.

Dioxin and endometrial progesterone resistance

Development of endometriosis likely requires multiple, interactive mechanisms involving both the endocrine and immune systems. Environmental toxicants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are of particular interest as potential contributory agents in the development of this disease because they can disrupt both systems. Nevertheless, defining the potential role that environmental exposure to TCDD plays in the development of endometriosis requires a better understanding of how this toxicant affects the biological processes that promote the disease. Although the disease mechanism(s) responsible for progesterone resistance in the endometrium of endometriosis patients remains speculative, our studies indicate that developmental exposure of mice to TCDD leads to a progesterone-resistant phenotype in adult animals that can persist for several generations. These studies and others underscore the importance of developing a greater understanding of the mechanisms of TCDD action that relate to reproductive disorders such as endometriosis.

Silencing of the JNK pathway maintains progesterone receptor activity in decidualizing human endometrial stromal cells exposed to oxidative stress signals

Survival of the conceptus is dependent on continuous progesterone signaling in the maternal decidua but how this is achieved under conditions of oxidative stress that characterize early pregnancy is unknown. Using primary cultures, we show that modest levels of reactive oxygen species (ROS) increase sumoylation in human endometrial stromal cells (HESCs), leading to enhanced modification and transcriptional inhibition of the progesterone receptor (PR). The ability of ROS to induce a sustained hypersumoylation response, or interfere with PR activity, was lost upon differentiation of HESCs into decidual cells. Hypersumoylation in response to modest levels of ROS requires activation of the JNK pathway. Although ROS-dependent JNK signaling is disabled on decidualization, the cells continue to mount a transcriptional response, albeit distinct from that observed in undifferentiated HESCs. We further show that attenuated JNK signaling in decidual cells is a direct consequence of altered expression of key pathway modulators, including induction of MAP kinase phosphatase 1 (MKP1). Overexpression of MKP1 dampens JNK signaling, prevents hypersumoylation, and maintains PR activity in undifferentiated HESCs exposed to ROS. Thus, JNK silencing uncouples ROS signaling from the SUMO conjugation pathway and maintains progesterone responses and cellular homeostasis in decidual cells under oxidative stress conditions imposed by pregnancy.—Leitao, B., Jones, M. C., Fusi, L., Higham, J., Lee, Y. Takano, M., Goto, T., Christian, M., Lam, E. W.-F., Brosens, J. J. Silencing of the Jnk pathway maintains progesterone receptor activity in decidualizing human endometrial stromal cells exposed to oxidative stress signals.

Differential expression of NUDT9 at different phases of the menstrual cycle and in different components of normal and neoplastic human endometrium

OBJECTIVE

The human endometrium manifests different and distinct morphologies and physiologies during the different phases of the menstrual cycle. We aimed to determine which candidate genes demonstrate differential expression patterns in the endometrium during different phases of the menstrual cycle.

MATERIALS AND METHODS

Using differential display reverse transcription polymerase chain reaction to compare day 5 and day 18 human glandular endometrium obtained by laser capture microdissection, we identified a specific gene, NUDT9 (nucleoside diphosphate-linked moiety X motif 9). NUDT9 is known to function as a highly specific adenosine diphosphate ribose pyrophosphatase and has been mapped to chromosome 4q22.1. It gives rise to two alternatively spliced messenger RNAs, NUDT9alpha and NUDT9beta, encoding a member of the Nudix hydrolase family. In this study, we purified NUDT9 protein and produced an antibody, which we then used for immunohistochemical studies.

RESULTS

Using this anti-NUDT9 antibody, we successfully demonstrated that NUDT9 protein was differentially expressed in endometrial glandular cells at different phases of the menstrual cycle. NUDT9 was also found to be expressed more prominently in the epithelial glandular component than in the stromal component of human endometrial carcinomas.

CONCLUSION

We suggest that NUDT9 may be involved in the regulation of the menstrual cycle and may be related to the proliferation of glandular cells in the human endometrium.

Inflammatory pathways in female reproductive health and disease

Inflammation involves alterations to vascular and immune cell function. It is well recognised that many physiological reproductive events such as ovulation, menstruation, implantation and onset of labour display hallmark signs of inflammation. These are orchestrated by specific molecular pathways involving a host of growth factors, cytokines, chemokines and lipid mediators. Resumption of normal reproductive function involves prompt and proper resolution of these inflammatory pathways. Recent literature confirms that resolution of inflammatory pathways involves specific biochemical events that are activated to re-establish homeostasis in the affected tissue. Moreover, initiation and maintenance of inflammatory pathways are the key components of many pathologies of the reproductive tract and elsewhere in the body. The onset of reproductive disorders or disease may be the result of exacerbated activation and maintenance of inflammatory pathways or their dysregulated resolution. This review will address the role of inflammatory events in normal reproductive function and its pathologies.

Cyclin-dependent kinase inhibitor drugs as potential novel anti-inflammatory and pro-resolution agents

The cyclin-dependent kinase inhibitor (CDKi) drugs such as R-roscovitine have emerged as potential anti-inflammatory, pharmacological agents that can influence the resolution of inflammation. Usually, once an inciting inflammatory stimulus has been eliminated, resolution proceeds by prompt, safe removal of dominant inflammatory cells. This is accomplished by programmed cell death (apoptosis) of prominent effector, inflammatory cells typified by the neutrophil. Apoptosis of neutrophils ensures that toxic neutrophil granule contents are securely packaged in apoptotic bodies and expedites phagocytosis by professional phagocytes such as macrophages. A panel of CDKi drugs have been shown to promote neutrophil apoptosis in a concentration- and time-dependent manner and the archetypal CDKi drug, R-roscovitine, overrides the anti-apoptotic effects of powerful survival factors [including lipopolysaccharide (LPS) and granulocyte macrophage-colony stimulating factor (GM-CSF)]. Inflammatory cell longevity and survival signalling is integral to the inflammatory process and any putative anti-inflammatory agent must unravel a complex web of redundancy in order to be effective. CDKi drugs have also been demonstrated to have significant effects on other cell types including lymphocytes and fibroblasts indicating that they may have pleiotropic anti-inflammatory, pro-resolution activity. In keeping with this, CDKi drugs like R-roscovitine have been reported to be efficacious in resolving established animal models of neutrophil-dominant and lymphocyte-driven inflammation. However, the mechanism of action behind these powerful effects has not yet been fully elucidated. CDKs play an integral role in the regulation of the cell cycle but are also recognized as participants in processes such as apoptosis and transcriptional regulation. Neutrophils have functional CDKs, are transcriptionally active and demonstrate augmented apoptosis in response to CDKi drugs, while lymphocyte proliferation and secretory function are inhibited. This review will discuss current understanding of the processes of inflammation and resolution but will focus on CDKis and their potential mechanisms of action.

Effects of antiprogestins on the uterus

Progesterone-receptor modulators (PRMs) are progesterone-receptor ligands that can exert agonistic, antagonistic or mixed agonist-antagonist effects depending on the cellular context. The mechanisms of action of these compounds are still incompletely understood. PRMs already have several applications in women's health such as emergency contraception, pregnancy termination, management of early fetal demise and cervical maturation. The main indications that will be developed in the future include dysfunctional bleeding and preoperative treatment of uterine myomas. Other future indications may include estrogen-free contraception, treatment of endometriosis and prevention and treatment of breast cancer. However, the available data from mid- to long-term continuous administration studies has raised the issue of endometrial safety. For this reason, long-term applications of PRMs are currently postponed, although windows of treatment with a short course of progestin therapy, or even by a short interruption of treatment, could improve endometrial aspects if needed.

Non-genomic progesterone actions in female reproduction

BACKGROUND

The steroid hormone progesterone is indispensable for mammalian procreation by controlling key female reproductive events that range from ovulation to implantation, maintenance of pregnancy and breast development. In addition to activating the progesterone receptors (PRs)-B and -A, members of the superfamily of ligand-dependent transcription factors, progesterone also elicits a variety of rapid signalling events independently of transcriptional or genomic regulation. This review covers our current knowledge on the mechanisms and relevance of non-genomic progesterone signalling in female reproduction.

METHODS

PubMed was searched up to August 2008 for papers on progesterone actions in ovary/breast/endometrium/myometrium/brain, focusing primarily on non-genomic signalling mechanisms.

RESULTS

Convergence and intertwining of rapid non-genomic events and the slower transcriptional actions critically determine the functional response to progesterone in the female reproductive system in a cell-type- and environment-specific manner. Several putative progesterone-binding moieties have been implicated in rapid signalling events, including the 'classical' PR and its variants, progesterone receptor membrane component 1, and the novel family of membrane progestin receptors. Progesterone and its metabolites have also been implicated in the allosteric regulation of several unrelated receptors, such as gamma-aminobutyric acid type A, oxytocin and sigma(1) receptors.

CONCLUSIONS

Identification of the mechanisms and receptors that relay rapid progesterone signalling is an area of research fraught with difficulties and controversy. More in-depth characterization of the putative receptors is required before the non-genomic progesterone pathway in normal and pathological reproductive function can be targeted for pharmacological intervention.

C-reactive protein across the menstrual cycle

C-reactive protein (CRP) is a widely used, sensitive biomarker of inflammation. Studies conducted among users of exogenous hormones suggest that estrogen increases CRP, whereas progesterone decreases CRP. Examinations of CRP in normally cycling women suggest the opposite: CRP is negatively associated with endogenous estrogen and positively associated with endogenous progesterone. This work evaluates the association between menstrual cycle-related hormone changes and events (menstruation and ovulation) and CRP. Eight female subjects gave urine and blood samples from twelve days across the menstrual cycle, for a total of eleven cycles. Blood samples were assayed for CRP; urine samples for beta-follicle stimulating hormone (betaFSH), pregnanediol 3-glucuronide (PDG), and estrone glucuronide (E1G). Ovulation day was estimated using hormone levels. Presence or absence of menses was reported by subjects. Analyses were conducted with random-effects linear regression. All cycles were ovulatory; day of ovulation was identified for nine cycles. A ten-fold increase in progesterone was associated with a 23% increase in CRP (P = 0.01), a ten-fold increase in estrogen was associated with a 29% decrease in CRP (P = 0.05), and menses was associated with a 17% increase in CRP (P = 0.18); no association between ovulation or FSH and CRP was found. Hormone changes across the menstrual cycle should be controlled for in future studies of inflammation in reproductive-age women.

Premenstrual regulation of the pro-angiogenic factor CYR61 in human endometrium

The pro-angiogenic factor cysteine-rich protein 61 (CYR61/CCN1) mediates different signals in tumorigenesis, angiogenesis and is involved in the pathogenesis of endometriosis. In this study we investigated the temporal and spatial expression pattern in human endometrium during the menstrual cycle and its possible regulation mechanisms in the premenstrual phase. CYR61 transcript expression showed two distinct periods of elevated levels in the proliferative phase and in menstrual effluents. Because the menstrual breakdown of the functionalis is triggered by cytokines, prostaglandins (PGs), as well as hypoxia, we used a benign endometrial cell line to investigate if CYR61 is regulated by these factors. Hypoxic conditions transiently induced CYR61 mRNA levels and enhanced the secretion of the CYR61 protein into the medium. The hypoxia-inducible factor (HIF) 1alpha mediated this effect on CYR61 as evidenced by dimethyloxalylglycine treatment and by HIF1alpha short interfering RNA. CYR61 mRNA expression was further regulated by IL-1, TNFalpha, PGE2, and PGF2alpha. In addition, TNFalpha and PGE2 elevated significantly CYR61 cellular protein levels in well-oxygenated cells but had only a slight effect on the quantity of secreted protein. Moreover, PGE2 combined with hypoxic conditions increased CYR61 mRNA and protein levels synergistically, whereas the combination with TNFalpha abolished the CYR61 levels induced by hypoxia. Together, the up-regulation of CYR61 by hypoxia via HIF1alpha, TNFalpha, and PGE2 could represent possible mechanisms for the CYR61 increase at the onset of menstruation. The opposite effect of TNFalpha combined with hypoxia on CYR61 up-regulation could contribute to a balanced expression level of this angiogenic factor in the endometrium.

Innate Immunity in the Female Reproductive Tract: Role of Sex Hormones in Regulating Uterine Epithelial Cell Protection Against Pathogens

The mucosal immune system in the upper female reproductive tract is uniquely prepared to maintain a balance between the presence of commensal bacteria, sexually transmitted bacterial and viral pathogens, allogeneic spermatozoa, and an immunologically distinct fetus. At the center of this dynamic system are the epithelial cells that line the Fallopian tubes, uterus, cervix and vagina. Epithelial cells provide a first line of defense that confers continuous protection, by providing a physical barrier as well as secretions containing bactericidal and virucidal agents. In addition to maintaining a state of ongoing protection, these cells have evolved to respond to pathogens, in part through Toll-like receptors (TLRs), to enhance innate immune protection and, when necessary, to contribute to the initiation of an adaptive immune response. Against this backdrop, epithelial cell innate and adaptive immune function is modulated to meet the constraints of procreation. The overall goal of this review is to focus on the dynamic role of epithelial cells in the upper reproductive tract, with special emphasis on the uterus, to define the unique properties of these cells as they maintain homeostasis in preparation for successful fertilization and pregnancy while at the same time confer protection against sexually transmitted infections, which threaten to compromise women's reproductive health and survival. By understanding the nature of this protection and the ways in which innate and adaptive immunity are regulated by sex hormones, these studies provide the opportunity to contribute to the foundation of information essential for ensuring reproductive health.

Transforming growth factor-beta1 attenuates expression of both the progesterone receptor and Dickkopf in differentiated human endometrial stromal cells

TGFbeta1 is thought to be intimately involved in cyclic tissue remodeling and inflammatory events associated with menstruation. Menstruation is initiated by progesterone withdrawal; however, the underlying mechanisms are not well understood. In the present study, we have tested the hypothesis that locally produced TGFbeta1 may influence expression of progesterone receptor (PR) or the Wnt antagonist Dickkopf-1 (DKK) with consequential impact on regulation of menstruation. Endometrial stromal cells (ESC) were isolated from endometrial biopsy samples collected from patients undergoing gynecological procedures for benign indications. Treatment of differentiated ESC with TGFbeta1 (10 ng/ml) significantly inhibited the expression of mRNAs encoding PR and DKK. TGFbeta1 also attenuated the protein expression of PR and secretion of DKK proteins in culture supernatants. Neutralization of endogenous TGFbeta1 signaling abolished the TGFbeta1-induced effects, significantly increased expression of PR, and increased DKK protein release levels to that of differentiated ESCs, confirming the specificity of the TGFbeta1 effect. Additionally, in vitro decidualization of ESCs significantly augmented DKK protein release. Moreover, although TGFbeta1 was capable of signaling via the Sma- and mothers against decapentaplegic (MAD)-related protein (SMAD) pathway, the inhibitory effect on DKK was SMAD independent. Conversely, the inhibitory effect of TGFbeta1 on PR was dependent on SMAD signal transduction. In conclusion, these results suggest that local TGFbeta1 signaling can potentiate progesterone withdrawal by suppressing expression of PR and may coordinate tissue remodeling associated with menstruation by inducing Wnt-signaling via inhibition of DKK, which we found to be up-regulated as a consequence of decidualization of ESCs.

Immunoendocrine aspects of endometrial function and implantation

Effective ovarian and uterine function relies on a complex interplay between the endocrine and immune systems. It is generally accepted that in reproductive tissues, oestradiol and progesterone have pro- and anti-inflammatory activities respectively and, in this regard, the paracrine effects of the sex steroids on the ovary are similar to the endocrine effects on the uterus. Ovarian leukocyte recruitment and cytokine release are central to follicle development, ovulation and corpus luteum function. At the uterine level, the cyclical changes in sex steroids regulate the number and distribution of endometrial and decidual immune cells as well as other immune signalling and surveillance factors. The uterine mucosa is unique, in that it must tolerate sperm and the allogeneic blastocyst in a way that does not compromise uterine immune surveillance against bacteria, yeast and viruses. Crosstalk between the sex steroids and immune mediators (systemic and local) are central to these functions, and this article will review these mechanisms and their importance for successful reproductive function and pregnancy success.

C-reactive protein before and after weight loss in overweight women with and without polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is associated with reproductive and metabolic abnormalities. It is unknown whether overweight women with and without PCOS achieve similar benefits from weight loss for cardiovascular risk factors.

METHOD

Overweight body mass index-matched women with (n = 15) and without (n = 17) PCOS (weight, 95.3 +/- 17.6 kg; body mass index, 35.6 +/- 5.3 kg/m(2), mean +/- sd) followed an 8-wk weight loss regime.

RESULTS

All subjects had similar reductions in weight (3.9 +/- 3.6 kg, 3.8%, vs. 4.5 +/- 4.1 kg, 4.7%, respectively, for PCOS and non-PCOS), waist circumference, fat mass, triglycerides, free testosterone, and fasting and postprandial insulin. At baseline, C-reactive protein (CRP) between groups was not significantly different (5.5 +/- 3.1 mg/liter for PCOS vs. 4.9 +/- 3.0 mg/liter for non-PCOS). There was a significant interaction between PCOS status and CRP (P = 0.016) such that CRP decreased with weight loss for non-PCOS women (-1.2 +/- 1.8 mg/liter; P = 0.025) but not for PCOS women. For all women, the change in CRP correlated with the change in weight (r = 0.560; P = 0.003), fat mass (r = 0.477; P = 0.016), and postprandial insulin (r = 0.402; P = 0.046). Adiponectin, IL-6, and TNF-alpha were not significantly different between groups before or after weight loss. Only subjects with baseline CRP levels below the median (4.52 mg/liter) showed increases in adiponectin (0.98 +/- 1.3 microg/liter) (P = 0.015) and greater reductions in triglycerides (P = 0.001) with weight loss.

CONCLUSION

A 4-5% weight loss improved lipid, glucose, and insulin profiles in women with and without PCOS. This degree of weight loss was not effective in lowering CRP concentrations in PCOS women, suggesting that greater weight loss is required in this group to achieve equivalent cardiovascular benefit to non-PCOS women.

Mifepristone induced progesterone withdrawal reveals novel regulatory pathways in human endometrium

In women, a single dose of the antiprogestin mifepristone (RU486) in the secretory phase rapidly renders the endometrium unreceptive and is followed by endometrial breakdown and menstruation within 72 h. This model provides a system to identify progesterone-regulated genes, which may be involved in endometrial receptivity and the induction of menstruation. We used cDNA microarrays to monitor the response of the endometriuim over 24 h following administration of mifepristone in the mid-secretory phase. We identified 571 transcripts whose expression was significantly altered, representing 131 biochemical pathways. These include new progesterone regulated members of the Wnt, matrix metalloproteinase (MMP), prostaglandin (PG) and chemokine regulatory pathways. Transcripts involved in thyroid hormone metabolism and signalling such as type II iodothyronine deiodinase and thyroid receptors were also found to be highly regulated by progesterone antagonism in the endometrium. Transcripts required for thyroid hormone synthesis such as thyroid peroxidase (TPO) and thyroglobulin (TG) were also expressed, indicating that the endometrium may be a site of thyroxin production. These results add to the existing knowledge of the role of the Wnt, chemokine, MMP and PG pathways in receptivity and early menstrual events. They provide in vivo evidence supporting direct or indirect regulation of many new transcripts by progesterone. We have also identified for the first time the very early transcriptional changes in vivo in response to progesterone withdrawal. This greatly increases our understanding of the pathways leading to menstruation and may provide new approaches to diagnose and treat menstrual disorders.

Endometrial bleeding

Abnormal bleeding is a significant health problem, especially during adolescence and before menopause when anovulatory cycles are common. Curettage is rarely necessary to investigate or treat menstrual problems in adolescents, and its use should also be minimized in women younger than 40 years. In every age group, medical treatment is the initial choice, but surgical treatment by endometrial destruction or hysterectomy is sometimes required. Benign causes of bleeding include fibroids and possibly adenomyosis, but the indications for treatment in each case depend upon the extent of bleeding, not the extent of the lesion. Breakthrough bleeding (BTB) with combined oral contraceptives commonly leads to discontinuation of the method. As BTB tends to improve with time, in the first 3 months of pill use, unless there are obvious underlying causes, women should be reassured that it will likely settle. BTB is often the reason for discontinuing progestogen-only contraception, and there is a need for effective means of treating unscheduled bleeding. Bleeding occurs in approximately 3% of post-menopausal women, and the use of hormones increases the likelihood of bleeding by >5-fold. Knowledge of the underlying mechanisms of bleeding is essential to the development of effective treatment.

Quantitative cellular and molecular analysis of the effect of progesterone withdrawal in a murine model of decidualization

The endometrium is a dynamic tissue that undergoes periodic growth, remodeling and breakdown under the influence of ovarian steroid hormones. To investigate the molecular mechanisms underlying these processes, we used a murine model to mimic the decidualization and regression observed in humans. Ovariectomized mice were treated sequentially with steroid hormones, and subsequently, to induce decidualization, oil was injected into the uterine lumen. The animals were then divided into progesterone-maintained and progesterone-withdrawal groups. In the latter group, a process similar to menstruation was induced. The uterine tissues were collected at several time-points after the induction of decidualization. Histological analysis demonstrated that decidualization and tissue degeneration were successfully induced with similar features to those observed during the human menstrual cycle. Immunohistochemical, morphometric, and microarray-based techniques were used to study the cellular and molecular changes. The volume fractions of leukocytes, macrophages, and neutrophils, but not endothelial cells, increased in decidualized uteri and decreased after major tissue degradation was completed. The microarray data show that the levels of many transcripts that encode immune-related factors changed during the time-course used for this model, and the transcript levels of many of these factors paralleled the changes observed in the volume fractions of the immune cells. The results of the present study suggest that this model is a useful alternative to the use of non-human primates. Our findings also show that immune cells are recruited into the menstruating endometrium, and that immune-related genes are regulated in the uterus throughout menstruation.

Effect of the menstrual cycle and oral contraceptives on aromatase and cyclooxygenase-2 expression in adenomyosis

OBJECTIVES

To determine whether aromatase expression in the eutopic endometrium and adenomyotic foci is affected by previous use of oral contraceptives containing gestodene, and to determine whether changes in cyclooxygenase-2 (COX-2) expression occur in adenomyosis during the menstrual cycle.

PATIENT AND METHODS

This was a retrospective cohort study carried out in paraffin-embedded endometrial tissue obtained from patients with a histological diagnosis of adenomyosis obtained during the proliferative (n = 25) and luteal (n = 10) phases of the menstrual cycle and following the use of continuous oral contraception with gestodene/ethinyl estradiol (n = 7). COX-2 and aromatase expression were measured in both eutopic endometrium and adenomyotic foci using immunohistochemical methods.

RESULTS

Aromatase expression was detected in 80% of the endometrial slices by immunohistochemistry. In positive cases, aromatase was mainly detected in the stromal cells of the eutopic endometrium, whereas in the adenomyotic foci this expression was negative in the majority of the cases. Oral contraceptives containing gestodene, on the other hand, were effective in suppressing aromatase expression in both eutopic and ectopic endometrium. COX-2 expression was detected by immunohistochemistry in the glandular epithelium of both eutopic endometrium and adenomyotic foci and there were no significant changes in its intensity throughout the menstrual cycle.

CONCLUSION

Aromatase expression in the eutopic endometrium and adenomyotic foci is suppressed by oral contraceptives containing gestodene. Increased aromatase activity may be responsible for the persistent COX-2 expression during the luteal phase.

The estrogenic effects of Polygonum hydropiper root extract induce follicular recruitment and endometrial hyperplasia in female albino rats

INTRODUCTION

The powdered dry root of Polygonum hydropiper is widely used by a certain ethnic group of women in Assam, India, for the prevention of undesired pregnancy.

METHOD

In the present investigation, the estrogenic property of the crude root extract (CRE) of P. hydropiper [compared to estradiol-17beta (E(2)), the reference drug] was tested in ovary-intact and ovariectomized (OVX) rats. The study was carried out by histological observations of ovarian follicles in an ovary-intact model and by histological observations of the endometrial epithelium in both OVX and ovary-intact female albino rats. Serial sections of the ovary and of the uterus were stained with routine hematoxylin-eosin and were observed under a microscope.

RESULTS

In the ovary-intact model, CRE induced follicular recruitment, while it promoted follicular atresia at a later stage. Many of the graafian follicles in the treated ovary showed pyknosis of the nuclei of granulosa and theca cells, as well as disparity in granulosa cell organization. In the uterine tissues of both ovary-intact and OVX rats, CRE induced hyperplasia in places of luminal epithelium and degeneration of endometrial glands. In OVX rats, the effect of CRE on uterine endometrium was corroborative with the effect of E(2).

CONCLUSIONS

Oral administration of the CRE of P. hydropiper significantly altered the histological structures of both ovary-intact and OVX rats.

Doxycycline alters the expression of inflammatory and immune-related cytokines and chemokines in human endometrial cells: implication in irregular uterine bleeding*

BACKGROUND

Increased production of pro-inflammatory mediators is considered central in the manifestation of events leading to irregular uterine bleeding in progestin-only contraceptive users. Evidence suggests that in addition to its antimicrobial property, doxycycline (Dox) acts as an anti-inflammatory agent mainly through the suppression of pro-inflammatory mediators.

METHODS

We tested this hypothesis in the endometrial environment using an in vitro model consisting of isolated human endometrial glandular epithelial and stromal cells and a human endometrial surface (HES) epithelial cell line cultured under defined conditions.

RESULTS

We found that Dox at doses ranging from 1 to 100 microg/ml had a limited growth-inhibitory effect on these cells, whereas Dox in a dose-dependent manner inhibited the production of tumour necrosis factor-alpha (TNF-alpha). Using multiplex cytokine/chemokine protein analysis to test a broader range of Dox activity, we found that Dox at 25 microg/ml either alone or in the presence of 17beta-estradiol (E2), medroxyprogesterone acetate (MPA) and E2+MPA (10(-8) M) as well as TNF-alpha (25 ng/ml), representing the endometrial environment exposed to contraceptives as well as inflammatory conditions, respectively, altered the production of multiple cytokines and chemokines as compared with untreated controls. These actions of Dox occurred in cell-, ovarian steroid- and cytokine/chemokine-dependent manners. Although Dox reduced the regulatory action of steroids on the production of these cytokines/chemokines, it was less effective on TNF-alpha-treated cells.

CONCLUSIONS

The results support the hypothesis that Dox, by modulating the endometrial expression of multiple inflammatory-related cytokines/chemokines in a cell- and cytokine/chemokine-dependent manner, may have a therapeutic potential in patients experiencing irregular uterine bleeding, in particular in progestin-dominant contraceptive users.