Implantation and the survival of early pregnancy

Peri-implantation pelvic inflammatory disease with normal pregnancy outcome

OBJECTIVE

To report on the presentation, diagnostic assessment, treatment, and outcome of a case of peri-implantation pelvic inflammatory disease.

DESIGN

Case report.

SETTING

Emergency department and gynecology ward of a tertiary university hospital.

PATIENT(S)

A 25-year-old multiparous woman in her 1st month of pregnancy.

INTERVENTION(S)

Diagnostic laparoscopy, antibiotic therapy, and pregnancy surveillance.

MAIN OUTCOME MEASURE(S)

Surveillance and outcome of pregnancy.

RESULT(S)

The patient presented with abdominal pain and fever 26 days after her last menstrual period. Examination revealed peritoneal irritation and cervical tenderness, with free fluid in the pelvis. Diagnostic laparoscopy was performed, with no evidence of ectopic pregnancy. A significant quantity of yellow purulent fluid was drained from the pelvis, which cultured for Escherichia coli. Antibiotic therapy yielded excellent response. The pregnancy continued, with no complications, to healthy term delivery.

CONCLUSION(S)

This rare diagnosis of peri-implantation pelvic inflammatory disease should be considered in the differential diagnosis of abdominal pain in early pregnancy. Timely, rational treatment, including early pelvic drainage and appropriate antibiotic therapy, may save the pregnancy.

Kisspeptins and the placenta: regulation of trophoblast invasion

The invasion of extravillous trophoblasts into the uterine wall is of crucial importance for placental and fetal development, and its dysregulation has been implicated in a wide spectrum of abnormal pregnancies. Mechanistically, trophoblast invasion strongly resembles the invasion of tumour cells, but differs from it by tight regulation in time and space. This regulation is accomplished by different factors including cytokines and hormones, which are produced by both fetal as well as maternal tissues i.e., placenta and uterus, respectively. Recently, products of the KiSS-1 gene (kisspeptins) have been identified to not only inhibit metastasis in various tumours, but also to repress trophoblast invasion via binding to the G protein-coupled receptor KiSS-1R. In the placenta, expression levels of kisspeptins and their receptor are highest in the first trimester in humans and at day 12.5 in rats, respectively. This coincides with the time when invasiveness peaks and invasion regulation is of central importance. Human kisspeptins are predominantly produced by the syncytiotrophoblast, whereas KiSS-1R is additionally expressed on the invading extravillous trophoblasts indicating a paracrine regulation of extravillous trophoblast invasion by the syncytiotrophoblast. In the structurally different rat placenta both KiSS-1 and its receptor are predominantly expressed by the invasive trophoblast giant cells, thus establishing an autocrine system in the invasion regulation of this trophoblast subpopulation. Amongst all kisspeptins the highly conserved kisspeptin Kp-10 has strongest invasion inhibiting effects suggesting its major role in regulation of trophoblast invasion.

Effects of a preovulatory administered depot gonadotrophin-releasing hormone agonist on reproductive hormone levels and pregnancy outcome in gilts

The present study aimed to explore the influence of a preovulatory administered depot gonadotrophin-releasing hormone (GnRH) agonist (GnRHa; Decapeptyl Depot) on the endocrine parameters and pregnancy outcome of gilts (n = 6). A GnRHa-supported preovulatory luteinising hormone (LH) surge was detected in all treated gilts. LH pulses were abolished completely by depot GnRHa on Day 7 and partly on Day 21 of pregnancy. In this treatment group (n = 6) four gilts were pregnant at slaughter on Day 28. In the control group receiving Gonavet, a non-formulated GnRHa (n = 6), all pigs showed LH pulses and were pregnant at slaughter on Day 28 of gestation. Mean progesterone concentrations were elevated in controls during the early luteal phase and were similar for both groups during the implantation period. Mean concentration of unoccupied progesterone receptor was significantly higher in uterine myometrium than in endometrium, but without treatment effects. Peripheral estrone sulfate concentrations showed a similar increase in all pregnant gilts on Days 17 and 18, and remained elevated. In summary, treatment with a depot GnRHa for synchronisation of ovulation alters pulsatile LH secretion during early pregnancy in pigs. In general, this alteration seems not to exert an injurious influence on luteal function and, therefore, on embryo and early fetal development.

Developmental regulation of human cytomegalovirus receptors in cytotrophoblasts correlates with distinct replication sites in the placenta

Cytomegalovirus (CMV), the major viral cause of congenital disease, infects the uterus and developing placenta and spreads to the fetus throughout gestation. Virus replicates in invasive cytotrophoblasts in the decidua, and maternal immunoglobulin G (IgG)-CMV virion complexes, which are transcytosed by the neonatal Fc receptor across syncytiotrophoblasts, infect underlying cytotrophoblasts in chorionic villi. Immunity is central to protection of the placenta-fetal unit: infection can occur when IgG has a low neutralizing titer. Here we used immunohistochemical and function-blocking methods to correlate infection in the placenta with expression of potential CMV receptors in situ and in vitro. In placental villi, syncytiotrophoblasts express the virion receptor epidermal growth factor receptor (EGFR) but lack integrin coreceptors, and virion uptake occurs without replication. Focal infection can occur when transcytosed virions reach EGFR-expressing cytotrophoblasts that selectively initiate expression of alphaV integrin. In cell columns, proximal cytotrophoblasts lack receptors and distal cells express integrins alpha1beta1 and alphaVbeta3, enabling virion attachment. In the decidua, invasive cytotrophoblasts expressing coreceptors upregulate EGFR, thereby dramatically increasing susceptibility to infection. Our findings indicate that virion interactions with cytotrophoblasts expressing receptors in the placenta (i) change as the cells differentiate and (ii) correlate with spatially distinct sites of CMV replication in maternal and fetal compartments.

Recent advances in the prevention and treatment of congenital cytomegalovirus infections

Continued but slow progress has led to recent advances in our understanding that congenital cytomegalovirus (CMV) infection has occurred. We understand that the most severe congenital disease occurs following a primary maternal infection during pregnancy. We now have the ability to accurately diagnosis a primary maternal infection using serologic studies of single serum sample. For pregnant women with young children, we know that child-to-mother CMV transmission can probably be prevented by hygienic intervention, and that for pregnant women who have acquired a primary CMV infection, mother-to-fetal transmission is probably preventable using CMV hyperimmune globulin. Although additional studies are needed, treatment of congenitally infected fetuses or newborns should be possible using either CMV hyperimmune globulin or antiviral agents such as ganciclovir or its derivates. Finally, recent evidence indicates that CMV replicates in the placenta, impairs development, and causes inflammation and dysfunction. This plus the reversibility of many manifestations of congenital infection in the fetus and newborn indicate that congenital CMV disease is in part a syndrome of placental insufficiency.

Uterine natural killer cells: a specialized differentiation regulated by ovarian hormones

In adult females of many species, a transient population of natural killer (NK) cells appears in cycles within the uterine endometrium (lining). Appearance of these lymphocytes coincides with specific phases of the ovarian hormone cycle and/or early pregnancy. Studies in rodents, women, and pigs dominate the literature and suggest the uterine (u)NK cells are an activated subset sharing many but not all features with circulating or lymphoid organ-residing NK cells. During successful murine pregnancy, uNK cells appear to regulate initiation of structural changes in the feed arterial systems that support maternal endometrial tissue at sites of implantation and subsequent placental development. These changes, which reverse after pregnancy, create a higher volume arterial bed with flaccid vessels unresponsive to vasoactive compounds. These unique pregnancy-associated arterial changes elevate the volume of low-pressure, nutrient-rich, maternal arterial blood available to conceptuses. Regulation of the differentiation, activation, and functions of uNK cells is only partially known, and there is lively debate regarding whether and how uNK cells participate in infertility or spontaneous abortion. This review highlights the biology of uNK cells during successful pregnancy.

EMILIN1 represents a major stromal element determining human trophoblast invasion of the uterine wall

The detection of EMILIN1, a connective tissue glycoprotein associated with elastic fibers, at the level of the ectoplacental cone and trophoblast giant cells of developing mouse embryos (Braghetta et al., 2002) favored the idea of a structural as well as a functional role for this protein in the process of placentation. During the establishment of human placenta, a highly migratory subpopulation of extravillous trophoblasts (EVT), originating from anchoring chorionic villi, penetrate and invade the uterine wall. In this study we show that EMILIN1, produced by decidual stromal and smooth muscle uterine cells, is expressed in the stroma and in some instances as a gradient of increasing concentration in the perivascular region of modified vessels. This distribution pattern is consistent with the haptotactic directional migration observed in in vitro functional studies of freshly isolated EVT and of the immortalized HTR-8/SVneo cell line of trophoblasts. Function-blocking monoclonal antibodies against alpha4-integrin chain and against EMILIN1 as well as the use of EMILIN1-specific short interfering RNA confirmed that trophoblasts interact with EMILIN1 and/or its functional gC1q1 domain via alpha4beta1 integrin. Finally, membrane type I-matrix metalloproteinase (MT1-MMP) and MMP-2 were upregulated in co-cultures of trophoblast cells and stromal cells, suggesting a contributing role in the haptotactic process towards EMILIN1.

Milder ovarian stimulation for in-vitro fertilization reduces aneuploidy in the human preimplantation embryo: a randomized controlled trial

BACKGROUND

To test whether ovarian stimulation for in-vitro fertilization (IVF) affects oocyte quality and thus chromosome segregation behaviour during meiosis and early embryo development, preimplantation genetic screening of embryos was employed in a prospective, randomized controlled trial, comparing two ovarian stimulation regimens.

METHODS

Infertile patients under 38 years of age were randomly assigned to undergo a mild stimulation regimen using gonadotrophin-releasing hormone (GnRH) antagonist co-treatment (67 patients), which does not disrupt secondary follicle recruitment, or a conventional high-dose exogenous gonadotrophin regimen and GnRH agonist co-treatment (44 patients). Following IVF, embryos were biopsied at the eight-cell stage and the copy number of 10 chromosomes was analysed in 1 or 2 blastomeres.

RESULTS

The study was terminated prematurely, after an unplanned interim analysis (which included 61% of the planned number of patients) found a lower embryo aneuploidy rate following mild stimulation. Compared with conventional stimulation, significantly fewer oocytes and embryos were obtained following mild stimulation (P < 0.01 and < 0.05, respectively). Consequently, both regimens generated on average a similar number (1.8) of chromosomally normal embryos. Differences in rates of mosaic embryos suggest an effect of ovarian stimulation on mitotic segregation errors.

CONCLUSIONS

Future ovarian stimulation strategies should avoid maximizing oocyte yield, but aim at generating a sufficient number of chromosomally normal embryos by reduced interference with ovarian physiology.

Male pregnancy in seahorses and pipefish: beyond the mammalian model

Pregnancy has been traditionally defined as the period during which developing embryos are incubated in the body after egg-sperm union. Despite strong similarities between viviparity in mammals and other vertebrate groups, researchers have historically been reluctant to use the term pregnancy for non-mammals in recognition of the highly developed form of viviparity in eutherians. Syngnathid fishes (seahorses and pipefishes) have a unique reproductive system, where the male incubates developing embryos in a specialized brooding structure in which they are aerated, osmoregulated, protected and likely provisioned during their development. Recent insights into physiological, morphological and genetic changes associated with syngnathid reproduction provide compelling evidence that male incubation in these species is a highly specialized form of reproduction akin to other forms of viviparity. Here, we review these recent advances, highlighting similarities and differences between seahorse and mammalian pregnancy. Understanding the changes associated with the parallel evolution of male pregnancy in the two major syngnathid lineages will help to identify key innovations that facilitated the development of this unique form of reproduction and, through comparison with other forms of live bearing, may allow the identification of a common set of characteristics shared by all viviparous organisms.

Steroid receptor coactivator 2 is essential for progesterone-dependent uterine function and mammary morphogenesis: insights from the mouse--implications for the human

While the indispensability of the progesterone receptor (PR) in female reproduction and mammary morphogenesis is acknowledged, the coregulators preferentially recruited by PR to mediate its in vivo effects have yet to be fully delineated. To further parse the roles of steroid receptor coactivator (SRC)/p160 family members in P-dependent physiological processes, genetic approaches were employed to generate a mouse model (PR(Cre/+)SRC-2(flox/flox)) in which SRC-2 function was ablated specifically in cell-types that express the PR. Fertility evaluation revealed that while ovulation occurred normally in the PR(Cre/+)SRC-2(flox/flox) mouse, uterine function was markedly affected. Absence of SRC-2 in PR positive uterine cells contributed to an early block in embryo implantation, a phenotype not shared by knockouts for SRC-1 or -3. Although the PR(Cre/+)SRC-2(flox/flox) uterus could mount a partial decidual response, removal of SRC-1 in the PR(Cre/+)SRC-2(flox/flox) uterus resulted in a complete block in decidualization, confirming that uterine SRC-2 and -1 are both required for P-initiated transcriptional programs which lead to full decidualization. In the case of the mammary gland, whole-mount and histological analyses revealed the absence of significant branching morphogenesis in the hormone-treated PR(Cre/+)SRC-2(flox/flox) mammary gland, reinforcing an important role for mammary SRC-2 in cellular proliferative events that require PR. Based on the above and the observation that SRC-2 is expressed in many of the uterine and mammary cell-lineages in the human as observed in the mouse, we suggest that further investigations are warranted to gain additional insights into SRC-2's involvement in normal (and possibly abnormal) uterine and mammary cellular responses to progestins.

Epigenetic regulation of human trophoblastic cell migration and invasion

Pivotal to successful mammalian reproduction is the ability of a developing embryo to implant to the uterine wall and establish a nutrient supply via placentation. Herein, we have examined the potential epigenetic regulation of human trophoblastic cell migration and invasion by use of the choriocarcinoma cell line, BeWo. Treatment of BeWo cells with a DNA methyltransferase inhibitor, 5'-aza-2'-deoxycytidine (AZA), resulted in conversion of cell morphology to a nonmigratory phenotype. This was exemplified by the ability of AZA to prevent BeWo cell migration in wound healing and transwell migration assays. AZA consequently inhibited BeWo cell invasion through reconstituted basement membrane. Examination of components of the adherens junction complex pivotal for determination of cell phenotype revealed that AZA specifically increased the mRNA level of E-cadherin and plakoglobin (gamma-catenin), but not alpha-catenin and beta-catenin. AZA also increased the gene promoter activity of both plakoglobin and E-cadherin. Protein levels of both plakoglobin and E-cadherin were increased by AZA, and AZA enhanced their localization to sites of intercellular contact. Forced expression of plakoglobin and E-cadherin abrogated BeWo cell migration, indicative that repression of these genes was required for BeWo cell migration. Small interfering RNA-mediated depletion of the individual DNA methyltransferase (DNMT) molecules did not affect plakoglobin and E-cadherin promoter activity or BeWo cell migration. However, increases in plakoglobin and E-cadherin promoter activity and inhibition of BeWo cell migration was achieved with small interfering RNA-mediated depletion of both DNMT-3a and DNMT-3b. Epigenetic regulation of plakoglobin and E-cadherin is therefore pivotal for appropriate trophoblastic invasion in vitro.

Placental-related diseases of pregnancy: Involvement of oxidative stress and implications in human evolution

Miscarriage and pre-eclampsia are the most common disorders of human pregnancy. Both are placental-related and exceptional in other mammalian species. Ultrasound imaging has enabled events during early pregnancy to be visualized in vivo for the first time. As a result, a new understanding of the early materno-fetal relationship has emerged and, with it, new insight into the pathogenesis of these disorders. Unifying the two is the concept of placental oxidative stress, with associated necrosis and apoptosis of the trophoblastic epithelium of the placental villous tree. In normal pregnancies, the earliest stages of development take place in a low oxygen (O2) environment. This physiological hypoxia of the early gestational sac protects the developing fetus against the deleterious and teratogenic effects of O2 free radicals (OFRs). In miscarriage, development of the placento-decidual interface is severely impaired leading to early and widespread onset of maternal blood flow and major oxidative degeneration. This mechanism is common to all miscarriages, with the time at which it occurs in the first trimester depending on the aetiology. In contrast, in pre-eclampsia the trophoblastic invasion is sufficient to allow early pregnancy phases of placentation but too shallow for complete transformation of the arterial utero-placental circulation, predisposing to a repetitive ischaemia-reperfusion (I/R) phenomenon. We suggest that pre-eclampsia is a three-stage disorder with the primary pathology being an excessive or atypical maternal immune response. This would impair the placentation process leading to chronic oxidative stress in the placenta and finally to diffuse maternal endothelial cell dysfunction.

Maternal exposure to second-hand tobacco smoke and pregnancy outcome among couples undergoing assisted reproduction

BACKGROUND

Exposure to second-hand tobacco smoke is preventable, yet common. This study assessed relationships between maternal exposure to second-hand tobacco smoke and adverse pregnancy outcomes.

METHODS

We measured cotinine (a biomarker of tobacco smoke) in urine from 921 women undergoing assisted reproductive technologies (ARTs) between 1994 and 1998. We also collected information on self-reported exposure to second-hand smoke at home or at work, in addition to parental smoking during the women's childhood.

RESULTS

In crude analysis, creatinine-adjusted cotinine levels were associated with a slight decrease in implantation rate among non-smoking women (11.1% in the lowest cotinine quintile versus 8.2% in the highest cotinine quintile; P=0.13). However, in multivariate logistic regression, cotinine levels above the median were not associated with failed fertilization, failed implantation or spontaneous abortion, nor was there evidence of a dose-response relationship among cotinine quintiles. After excluding women in couples diagnosed with male factor infertility, there were increased odds of having a spontaneous abortion among non-smoking women who reported that both parents smoked while they were children growing up compared with women reporting that neither parent smoked [adjusted odds ratio (OR) = 4.35; 95% confidence interval (CI) = 1.04-18.1].

CONCLUSIONS

Female exposure to second-hand smoke as a child or in utero may be associated with an increased risk of spontaneous abortion in adulthood. However, this may be a chance finding due to multiple comparisons. Similar associations should be explored in additional studies with more refined estimates of childhood and in utero exposure to tobacco smoke.

Decidual stromal cell response to paracrine signals from the trophoblast: amplification of immune and angiogenic modulators

During the invasive phase of implantation, trophoblasts and maternal decidual stromal cells secrete products that regulate trophoblast differentiation and migration into the maternal endometrium. Paracrine interactions between the extravillous trophoblast and the maternal decidua are important for successful embryonic implantation, including establishing the placental vasculature, anchoring the placenta to the uterine wall, and promoting the immunoacceptance of the fetal allograph. To our knowledge, global crosstalk between the trophoblast and the decidua has not been elucidated to date, and the present study used a functional genomics approach to investigate these paracrine interactions. Human endometrial stromal cells were decidualized with progesterone and further treated with conditioned media from human trophoblasts (TCM) or, as a control, with control conditioned media (CCM) from nondecidualized stromal cells for 0, 3, and 12 h. Total RNA was isolated and processed for analysis on whole-genome, high-density oligonucleotide arrays containing 54,600 genes. We found that 1374 genes were significantly upregulated and that 3443 genes were significantly downregulated after 12 h of coincubation of stromal cells with TCM, compared to CCM. Among the most upregulated genes were the chemokines CXCL1 (GRO1) and IL8,CXCR4, and other genes involved in the immune response (CCL8 [SCYA8], pentraxin 3 (PTX3), IL6, and interferon-regulated and -related genes) as well as TNFAIP6 (tumor necrosis factor alpha-induced protein 6) and metalloproteinases (MMP1, MMP10, and MMP14). Among the downregulated genes were growth factors, e.g., IGF1, FGF1, TGFB1, and angiopoietin-1, and genes involved in Wnt signaling (WNT4 and FZD). Real-time RT-PCR and ELISAs, as well as immunohistochemical analysis of human placental bed specimens, confirmed these data for representative genes of both up- and downregulated groups. The data demonstrate a significant induction of proinflammatory cytokines and chemokines, as well as angiogenic/static factors in decidualized endometrial stromal cells in response to trophoblast-secreted products. The data suggest that the trophoblast acts to alter the local immune environment of the decidua to facilitate the process of implantation and ensure an enriched cytokine/chemokine environment while limiting the mitotic activity of the stromal cells during the invasive phase of implantation.

Steroid receptor coactivator 2 is critical for progesterone-dependent uterine function and mammary morphogenesis in the mouse

Although the essential involvement of the progesterone receptor (PR) in female reproductive tissues is firmly established, the coregulators preferentially enlisted by PR to mediate its physiological effects have yet to be fully delineated. To further dissect the roles of members of the steroid receptor coactivator (SRC)/p160 family in PR-mediated reproductive processes in vivo, state-of-the-art cre-loxP engineering strategies were employed to generate a mouse model (PR(Cre/+) SRC-2(flox/flox)) in which SRC-2 function was abrogated only in cell lineages that express the PR. Fertility tests revealed that while ovarian activity was normal, PR(Cre/+) SRC-2(flox/flox) mouse uterine function was severely compromised. Absence of SRC-2 in PR-positive uterine cells was shown to contribute to an early block in embryo implantation, a phenotype not shared by SRC-1 or -3 knockout mice. In addition, histological and molecular analyses revealed an inability of the PR(Cre/+) SRC-2(flox/flox) mouse uterus to undergo the necessary cellular and molecular changes that precede complete P-induced decidual progression. Moreover, removal of SRC-1 in the PR(Cre/+) SRC-2(flox/flox) mouse uterus resulted in the absence of a decidual response, confirming that uterine SRC-2 and -1 cooperate in P-initiated transcriptional programs which lead to full decidualization. In the case of the mammary gland, whole-mount and histological analysis disclosed the absence of significant ductal side branching and alveologenesis in the hormone-treated PR(Cre/+) SRC-2(flox/flox) mammary gland, reinforcing an important role for SRC-2 in cellular proliferative changes that require PR. We conclude that SRC-2 is appropriated by PR in a subset of transcriptional cascades obligate for normal uterine and mammary morphogenesis and function.

Progesterone supplementation to prevent recurrent miscarriage and to reduce implantation failure in assisted reproduction cycles

Implantation failure has been questioned for many cases of recurrent miscarriage and unsuccessful assisted reproduction. The exact cause of implantation failure is not known, but luteal phase defect is encountered in many of these cases. Consequently, women with recurrent miscarriages have been treated with progesterone supplementation with various degrees of success, and a recent meta-analysis has shown trends for improved live birth rates in those women. Progesterone probably acts as an immunological suppressant blocking T-helper (Th)1 activity and inducing release of Th2 cytokines. Numerous studies have confirmed that ovarian stimulation used in assisted reproduction is associated with luteal phase insufficiency, even when gonadotrophin-releasing hormone antagonists are used. In those patients, advanced endometrial histological maturity and a decrease in the concentration of cytoplasmic progesterone receptors are observed. Progesterone supplementation results in a trend towards improved ongoing and clinical pregnancy rates, except in patients treated with human menopausal gonadotrophin-only regimens, in whom ongoing pregnancy rates increase significantly. More randomized controlled trials are needed to increase the power of the currently available meta-analyses to further evaluate progesterone supplementation in both conditions.

Lysophosphatidic receptor, LPA3, is positively and negatively regulated by progesterone and estrogen in the mouse uterus

Reciprocal interactions between blastocysts and receptive uteri are essential for successful implantation. This process is regulated by the timely interplay of two ovarian hormones, progesterone and estrogen. However, the molecular targets of these hormones are largely unknown. We showed recently that a small bioactive lysophospholipid, lysophosphatidic acid, plays a pivotal role in the establishment of implantation via its cellular receptor, LPA(3). Here we demonstrate that LPA(3) expression is positively and negatively regulated by steroid hormones in mouse uteri. The LPA(3) mRNA level in the uteri increased during early pseudopregnancy, peaking around 3.5 days post coitus (3.5 d.p.c.), then, decreased to the basal level on 4.5 d.p.c. LPA(3) expression remained at a low level in ovariectomized mice, and administration of progesterone to ovariectomized mice up-regulated LPA(3) mRNA expression. In addition, simultaneous administration of estrogen counteracted the effect of progesterone. These results show that progesterone and estrogen cooperatively regulate LPA(3) expression, thereby contributing to the receptivity of uteri during early pregnancy.

Quantitative and morphological assessment of early gestational sacs using three-dimensional ultrasonography

OBJECTIVE

Our main objective was to determine the value of three-dimensional ultrasonography (3DUS) and Virtual Organ Computer-aided AnaLysis (VOCAL) in the evaluation of gestational sac volume and morphology during early pregnancy.

METHODS

Twenty-eight normal early pregnancies were scanned approximately every 2 weeks using transabdominal (TAS) and transvaginal (TVS) sonography. The VOCAL technique was used to create computerized surface models to classify gestational sac shapes as discoid or ellipsoid. Serial sac volume changes were analyzed using repeated measures ANOVA. Bland-Altman plots determined examiner bias and limits of agreement (LOA) for sac volume measurements. Gestational sac volumes were compared between the two-dimensional (2D) ellipsoid and VOCAL techniques. Differences between volume measurements were tested using the two-tailed paired t-test with statistical significance at the P < 0.05 level.

RESULTS

Each subject was examined at a mean +/- SD menstrual age of 7.9 +/- 0.6 weeks (Scan 1), 9.9 +/- 0.6 weeks (Scan 2), and 11.9 +/- 0.6 weeks (Scan 3). Sac volumes significantly increased over time from 22 +/- 11 mL at Scan 1, to 57 +/- 21 mL at Scan 2 and 116 +/- 35 mL at Scan 3 (P < 0.001). Predominant sac shapes were classified as ellipsoid (76.2%) or discoid (23.8%). Additional descriptors included: concave (60.7%), irregular (53.6%), or smooth (7.1%), with 19% of the overall group having more than one additional shape attribute. Clinically acceptable volume measurement bias and agreement were found for the following comparisons: (1) TAS versus TVS; (2) interobserver volume measurements; and (3) intraobserver volume measurements. The VOCAL technique yielded slightly greater sac volumes (64 +/- 45.4 mL) when compared to the 2D ellipsoid model (48.6 +/- 36.8 mL) (28.9 +/- 24.3% (95% limit of agreement range, - 18.7 to 76.5%), P < 0.001).

CONCLUSIONS

Reproducible sac volume measurements can be obtained using VOCAL with either TAS or TVS. Early gestational sacs variably appear as discoid or ellipsoid structures with a concave indentation from the placenta. Sac volumes can be underestimated if an ellipsoid shape is assumed. Morphological and quantitative analysis of the gestational sac may provide baseline parameters for studying patients at risk for early pregnancy failure.

Endocannabinoid signaling directs periimplantation events

An emerging concept in female reproduction is the role of endocannabinoids, a group of endogenously produced lipid mediators that bind to and activate cannabinoid receptors. Although adverse effects of cannabinoids in female reproduction have been implicated for years, the mechanisms by which they exert these effects remained elusive. With the identification of cannabinoid receptors, endocannabinoid ligands, their key synthetic and hydrolytic pathways, and the generation of knockout mouse models for cannabinoid receptors, a wealth of information is now available regarding the significance of cannabinoid/endocannabinoid signaling in early pregnancy. This review focuses on various aspects of endocannabinoid signaling in preimplantation embryo development and activation, and uterine differentiation during the periimplantation embryo-uterine dialog. It is hoped that a deeper understanding will lead to potential clinical applications of the endocannabinoid system as a target for regulating female fertility.

Role of aspartyl-(asparaginyl) beta-hydroxylase in placental implantation: Relevance to early pregnancy loss

Aspartyl-(asparaginyl) beta-hydroxylase (AAH) is a type 2 transmembrane protein with catalytic activity that hydroxylates epidermal growth factor-like domains of proteins that have a functional role in cell motility and invasion. Extravillous cytotrophoblasts (CTB) are motile and invasive unpolarized epithelial cells that mediate early implantation through interaction with the endometrium. This study characterizes the potential role of AAH in CTB implantation using human placentas from (1) terminated pregnancies (n = 11), (2) normal term deliveries (n = 21), (3) spontaneous abortuses (n = 21), and (4) small-for-gestational-age (SGA) term deliveries (n = 21). The SGA cases all had established clinical histories of intrauterine growth restriction or preeclampsia. Formalin-fixed, paraffin-embedded sections of placenta were immunostained using the 15C7 monoclonal antibody generated to recombinant AAH. In addition, snap-frozen or RNAlater-preserved specimens (Ambion, Austin, TX) were used for RNA analysis of AAH expression by real-time quantitative reverse transcriptase-polymerase chain reaction and protein analysis by Western blotting. The immunohistochemical staining studies demonstrated AAH expression in amniocytes, villous CTB, syncytiotrophoblast, extravillous CTB, decidua, and endometrial glands at all gestational ages and in all 4 groups. Higher levels of AAH immunoreactivity were observed in extravillous CTB compared with villous CTB. Immunohistochemical staining and RNA analysis demonstrated abundant AAH expression in placental trophoblastic cells as well as in decidua and endometrial glands, with reduced expression in spontaneous abortion and SGA, suggesting that AAH may serve as a biomarker of impaired implantation. The high levels of AAH in decidua and endometrial glands suggest a role for this molecule in "receptivity" of endometrium.

Jekyll and hyde: two faces of cannabinoid signaling in male and female fertility

Mammalian reproduction is a complicated process designed to diversify and strengthen the genetic complement of the offspring and to safeguard regulatory systems at various steps for propagating procreation. An emerging concept in mammalian reproduction is the role of endocannabinoids, a group of endogenously produced lipid mediators, that bind to and activate cannabinoid receptors. Although adverse effects of cannabinoids on fertility have been implicated for years, the mechanisms by which they exert these effects were not clearly understood. With the identification of cannabinoid receptors, endocannabinoid ligands, their key synthetic and hydrolytic pathways, and the generation of mouse models missing cannabinoid receptors, a wealth of information on the significance of cannabinoid/endocannabinoid signaling in spermatogenesis, fertilization, preimplantation embryo development, implantation, and postimplantation embryonic growth has been generated. This review focuses on various aspects of the endocannabinoid system in male and female fertility. It is hoped that a deeper insight would lead to potential clinical applications of the endocannabinoid signaling as a target for correcting infertility and improving reproductive health in humans.

A prospective study of early pregnancy loss in humans

OBJECTIVE

To test two hypotheses: In spontaneous conceptions, early pregnancy loss (EPL) is associated with [1] inadequate luteal (ovarian) P, and/or [2] elevated follicular (adrenal) P.

DESIGN

A population-based prospective study.

SETTING

Thirty rural Bolivian communities.

PATIENT(S)

Women volunteers (n = 191), 19-40 years old, in stable sexual unions and not using contraception.

INTERVENTION(S)

Collection of serial saliva samples throughout sequential ovarian cycles and urine samples during late luteal phases. Collections continued throughout pregnancy for each detected conception.

MAIN OUTCOME MEASURE(S)

Occurrence of spontaneous conceptions and subsequent outcomes. Salivary concentrations of P. Test for elevated urinary human chorionic gonadotropin (hCG).

RESULT(S)

Luteal (through implantation) P levels were similar in pregnancies lost within 5 weeks after conception (EPL; n = 8) and those pregnancies that were maintained longer (sustained conceptions, SC; n = 32). Follicular P was significantly higher in EPL than in SC.

CONCLUSION(S)

[1] Elevated follicular P was associated with EPL in natural conceptions in healthy women. [2] Early pregnancy loss exhibits absolute luteal P levels comparable to SC, but lower luteal/follicular P ratios.

Antibodies to β2-glycoprotein I and annexin V in women with early and late idiopathic recurrent spontaneous abortions

Anti-phospholipid antibodies (APA) are heterogeneous group of autoantibodies that target phospholipid or phospholipid-binding proteins. APAs were previously shown to induce several thrombotic states, including idiopathic recurrent spontaneous abortion (RSA). Unlike the contribution of the classical lupus anticoagulant (LAC) and anticardiolipin antibodies (ACA), the contribution of anti-beta2 glycoprotein 1 (beta2GPI) and anti-annexin V antibodies to RSA risk remain poorly understood. We assessed anti-beta2GPI and anti-annexin V IgM and IgG antibodies as RSA risk factors for RSA in 172 Tunisian women with >3 consecutive idiopathic pregnancy losses, together with 173 matched control women. The prevalence of anti-beta2GPI IgG (P=0.41, OR=1.64) and IgM (P=0.50, OR=1.70) were comparable between cases and controls. Higher anti-annexin V IgG (P=0.02, OR=5.28), but not IgM (P=0.25, OR=1.78), levels were seen in cases. Regression analysis showed that anti-beta2GPI IgM (OR=8.90; 95% CI=1.23-64.63) was associated with early RSA, while anti-annexin V IgG (OR=9.35, 95% CI=1.44-60.86) was associated with late RSA. For combined early + late RSA, the only variable selected was BMI (OR=0.93; 95% CI=0.87-0.99), and neither anti-annexin V nor anti-beta2GPI IgM and IgG were associated with early + late RSA. Anti-annexin V and anti-beta2GPI appear to be independent risk markers of RSA.

Human decidual natural killer cells as a source and target of macrophage migration inhibitory factor

The human uterine mucosa of early pregnancy is largely populated by CD56(bright) natural killer (NK) cells (uterine (u) NK cells). The specific functions of these cells are still unknown, but their interaction and response to foetal trophoblasts are thought to be important for the establishment of a successful pregnancy. The study reported herein shows that uNK cells respond to, and produce, macrophage migration inhibitory factor (MIF), a cytokine highly expressed in the human placenta and in the cyclic and pregnant endometrium. Recombinant human MIF reduced in a dose-dependent manner the cytolytic activity of purified uNK cells against K562 cells. RT-PCR, Western blot analysis and ELISA demonstrated the synthesis and secretion of the cytokine by uNK cells. Double immunofluorescence staining showed the presence of MIF in uterine CD56 + cells. Finally, neutralization of the endogenous cytokine by a polyclonal antibody resulted in a sharp increase in the cytolytic activity of uNK cells. These findings indicate the existence of a previously unrevealed paracrine and autocrine action of MIF on uNK cells and support its contribution to the immune privilege at the maternal-foetal interface.

Endometrial preparation for in vitro oocyte maturation: early use of estrogen increases endometrial tissue and requires lower daily dosage: a cross over trial in 'mock' cycles

PURPOSE

Determine if estrogen used since the beginning of the menstrual flow could improve endometrial tissue compared to standard endometrial preparation for in vitro maturation cycles.

METHODS

Twenty polycystic ovary syndrome women were submitted to two estrogen therapy schedules: standard schedule; estrogen began on the day of planned egg retrieval (dosage was based on endometrial thickness); and long schedule; estrogen began on the first day of menstruation. No oocyte retrieval or embryo transfer was performed. Three-dimensional ultrasound was performed on the day of planned egg retrieval and one week later for endometrial evaluation.

RESULTS

A higher endometrial thickness and volume was found in long schedule on both evaluations. The number of patients that have used 10 mg/day of estradiol was significant higher in the standard schedule (65%x0%). No other significant difference was found.

CONCLUSIONS

The early use of estrogen improves endometrial tissue and requires lower daily dosage.

Regulation of cyclooxygenase activity in cultured endometrial stromal cells by granulocyte-macrophage colony-stimulating factor

OBJECTIVE

To assess the ability of granulocyte-macrophage colony-stimulating factor (GM-CSF) to regulate cyclooxygenase (COX) enzyme activity and prostaglandins (PGs) synthesis, specifically PGE2 production in stromal cells, neither of which have been addressed in the literature.

DESIGN

Prospective study.

SETTING

Department of obstetrics and gynecology at a university hospital.

PATIENT(S)

Human luteal phase endometrium was obtained from surgical specimens (n = 6) for clinical indications.

INTERVENTION(S)

Confluent stromal cells were stimulated with GM-CSF.

MAIN OUTCOME MEASURE(S)

Expression of COX mRNA, COX enzyme activity, and PGE2 level in cultured stromal cells.

RESULT(S)

Confluent stromal cell cultures treated with P and E2 for 9 days were stimulated with GM-CSF. After treatment of 12 hours, low-dose GM-CSF (0.001-0.1 ng/mL) increased COX-2 mRNA levels in stromal cell, whereas high dose GM-CSF (1-100 ng/mL) decreased COX-1 and COX-2 mRNA levels. After treatment of 48 hours, low concentrations of GM-CSF (0.001-0.1 ng/mL) increased total COX and COX-2 enzyme activity, whereas high concentrations of GM-CSF (1-100 ng/mL) inhibited COX and COX-2 activity; The PGE2 levels decreased by 31% to 393.3 pg/mL (P < .05) with concentrations of GM-CSF increasing from 1 ng/mL to 100 ng/mL.

CONCLUSION(S)

There appeared to be a biphasic pattern of COX-2 enzyme response to GM-CSF with low concentrations increasing activity and high concentrations inhibiting activity. It is possible that GM-CSF may provide critical regulation of PG production in the preimplantation period.

A case-control study on the association of idiopathic recurrent pregnancy loss with autoantibodies against β2-glycoprotein I and annexin V

Whereas antiphospholipid antibodies (aPL) are associated with thrombotic events and recurrent spontaneous abortion (RSA), the contribution of anti-β2 glycoprotein 1 (β2GP1) and anti-annexin V antibodies as risk factors for RSA remain poorly understood. We investigated anti-β2-GPI and anti-annexin V IgM and IgG antibodies as potential risk factors for RSA in 200 women with more than three consecutive idiopathic RSA, and 200 age-matched, healthy, parous women. Pearson’s chi squared test analysis showed that while anti-β2-GPI IgG (P= 0.416) and IgM (P= 0.72) were comparable between patients and controls, elevated anti-annexin V IgG (P= 0.006), but not IgM (P= 0.084), was more pronounced in patients. Higher frequencies of elevated IgG-only (P= 0.005), but not IgM-only (P= 1.000; OR = 6.66), anti-annexin V antibodies were noted among patients. Multinomial regression analysis showed that body-mass index (overweight and obesity;P= 0.008), education status (P< 0.001) and anti-β2-GPI IgM (P= 0.033), but not IgG (P= 0.723), were associated with early abortion, while anti-β2-GPI IgG (P= 0.030) and anti-annexin V IgG (P= 0.004) were associated with late RSA. For combined early-late RSA, the only variable selected was education status (P< 0.001), and neither anti-annexin V nor anti-β2-GPI IgM and IgG was associated with early-late RSA. Accordingly, anti-annexin V and anti-β2-GPI should be regarded as independent risk markers of RSA.

Human embryo–conditioned medium stimulates in vitro endometrial angiogenesis

OBJECTIVE

Successful implantation and placentation depend on the interaction between the endometrium and the embryo. Angiogenesis is crucial at this time. In this article we investigate the direct influence of the human embryo on in vitro endometrial angiogenesis.

DESIGN

In vitro study.

SETTING

Human endometrial microvascular endothelial cells (hEMVEC) grown on an in vitro angiogenesis model.

INTERVENTION(S)

Conditioned media (CM) of human embryos were used to stimulate in vitro angiogenesis.

MAIN OUTCOME MEASURE(S)

In vitro angiogenesis of hEMVEC.

RESULT(S)

Conditioned media of human embryos, containing significant amounts of vascular endothelial growth factor (VEGF)-A, as determined by enzyme-linked immunosorbent assay (ELISA), caused an increase in hEMVEC tube formation. This effect was prevented by soluble VEGF receptor 1, which quenches VEGF-A activity. Recombinant EGF alone and leukemia inhibitory factor in combination with VEGF-A stimulated hEMVEC tube formation. None of the other tested recombinant mediators, which have been described as produced by the early embryo/trophoblast (interleukin (IL) 10, transforming growth factor (TGF) beta, placental growth factor, hCG, colony-stimulating factor 1, interferon-gamma, insulin-like growth factor I and II, IL-6, platelet-derived growth factor, and TGFalpha), had an effect on tube formation by hEMVEC.

CONCLUSION(S)

For the first time, it is shown that the human embryo is able to stimulate in vitro endometrial angiogenesis at the time of implantation, a process that is mediated by VEGF-A.

Natural Killer Cells and Dendritic Cells at the Human Feto-maternal Interface: an Effective Cooperation?

Human endometrium and in particular decidua, harbours a considerable population of immunocompetent cells. The most prominent of these are uterine natural killer (uNK) cells, which differ considerably from their peripheral blood counterparts in terms of both gene expression and function. Recently, the existence of DC-SIGN positive immature dendritic cells (DCs) in human decidua has been demonstrated. Evidence exists that immature DCs are required for the initiation and maintenance of peripheral tolerance, whereas mature DCs, which are only found in minimal amounts in human decidua, are associated with a Th1 polarization of T cells. Although the study of uNK-DC cross-talk is only beginning, it may in the future provide important insights into how acceptance of the fetus by the maternal immune system is mediated.

Endoplasmic reticulum aminopeptidase-1 mediates leukemia inhibitory factor-induced cell surface human leukocyte antigen-G expression in JEG-3 choriocarcinoma cells

Maternal immune tolerance is required for extravillous trophoblasts (EVTs) to invade the decidua without rejection. Endoplasmic reticulum aminopeptidase-1 (ERAP1) generates human leukocyte antigen (HLA) class I-adapted antigenic peptides, but its function in trophoblasts lacking classical HLA class I molecules remains undetermined. Leukemia inhibitory factor (LIF) is produced from decidua during the implantation period and plays a necessary role in establishing pregnancy. This study is intended to investigate the location and the function of ERAP1 in trophoblastic cells, focusing on LIF. Immunohistochemistry showed strong ERAP1 expression in cultured EVTs. In choriocarcinoma cell lines used as a model for trophoblasts, ERAP1 was expressed more intensively in JEG-3 than BeWo cells. Immunoblot analysis and immunocytochemistry localized ERAP1 to the endoplasmic reticulum (ER) in JEG-3 cells. Flow cytometry with HLA-G antibody to monitor the supply of antigenic peptides presenting to HLA-G in the ER showed that reducing ERAP1 transcripts by RNA interference did not affect cell surface expression of membrane HLA-G1 (mHLA-G1) in JEG-3 cells under basal conditions. In LIF-treated JEG-3 cells, cell surface mHLA-G1 expression was increased along with ERAP1 protein and promoter activities. In contrast to nonstimulated cells, eliminating ERAP1 from LIF-treated JEG-3 cells reduced the cell surface mHLA-G1 expression and soluble HLA-G1 secretion. This study provides the first evidence showing that ERAP1 is localized in the ER of trophoblasts and is involved in regulating cell surface HLA-G expression in the presence of LIF. Consequently, ERAP1 would function to present antigenic peptides to HLA-G in trophoblasts.

Nerve Growth Factor Translates Stress Response and Subsequent Murine Abortion via Adhesion Molecule-Dependent Pathways1

Spontaneous abortion is a frequent threat affecting 10%-25% of human pregnancies. Psychosocial stress has been suggested to be attributable for pregnancy losses by challenging the equilibrium of systems mandatory for pregnancy maintenance, including the nervous, endocrine, and immune system. Strong evidence indicates that stress-triggered abortion is mediated by adhesion molecules, i.e., intercellular adhesion molecule 1 (ICAM1) and leukocyte function associated molecule 1, now being referred to as integrin alpha L (ITGAL), which facilitate recruitment of inflammatory cells to the feto-maternal interface. The neurotrophin beta-nerve growth factor (NGFB), which has been shown to be upregulated in response to stress in multiple experimental settings including in the uterine lining (decidua) during pregnancy, increases ICAM1 expression on endothelial cells. Here, we investigated whether and how NGFB neutralization has a preventive effect on stress-triggered abortion in the murine CBA/J x DBA/2J model. We provide experimental evidence that stress exposure upregulates the frequency of abortion and the expression of uterine NGFB. Further, adhesion molecules ICAM1 and selectin platelet (SELP, formerly P-Selectin) and their ligands ITGAL and SELP ligand (SELPL, formerly P selectin glycoprotein ligand 1) respectively increase in murine deciduas in response to stress. Subsequently, decidual cytokines are biased toward a proinflammatory and abortogenic cytokine profile. Additionally, a decrease of pregnancy protective CD8alpha(+) decidual cells is present. Strikingly, all such uterine stress responses are abrogated by NGFB neutralization. Hence, NGFB acts as a proximal mediator in the hierarchical network of immune rejection by mediating an abortogenic environment comprised of classical signs of neurogenic inflammation.

Impact of hypnosis during embryo transfer on the outcome of in vitro fertilization-embryo transfer: a case-control study

OBJECTIVE

To investigate whether hypnosis during ET contributes to successful IVF/ET outcome.

DESIGN

Case-control clinical study.

SETTING

Academic Fertility and IVF Unit, Soroka Medical Center, Beer-Sheva, Israel.

PATIENT(S)

Infertile couples undergoing IVF.

INTERVENTION(S)

Ninety-eight IVF/ET cycles with hypnosis during the ET procedure were matched with 96 regular IVF/ET cycles.

MAIN OUTCOME MEASURES

Comparison of clinical pregnancy and implantation rates between the two groups.

RESULT(S)

We obtained 52 clinical pregnancies out of 98 cycles (53.1%) with an implantation rate of 28% among hypnosis IVF/ET cycles, and 29 out of 96 (30.2%) clinical pregnancies and an implantation rate of 14.4% in the control cycles. Our overall IVF program pregnancy rate for the same period was 32.1%. Logistic regression analysis was performed emphasizing the positive contribution of hypnosis to the IVF/ET conception rates.

CONCLUSION(S)

This study suggests that the use of hypnosis during ET may significantly improve the IVF/ET cycle outcome in terms of increased implantation and clinical pregnancy rates. Furthermore, it seems that the patients' attitude to the treatment was more favorable.

Cortisol levels and very early pregnancy loss in humans

Maternal stress is commonly cited as an important risk factor for spontaneous abortion. For humans, however, there is little physiological evidence linking miscarriage to stress. This lack of evidence may be attributable to a paucity of research on maternal stress during the earliest gestational stages. Most human studies have focused on "clinical" pregnancy (>6 weeks after the last menstrual period). The majority of miscarriages, however, occur earlier, within the first 3 weeks after conception (approximately 5 weeks after the last menstrual period). Studies focused on clinical pregnancy thus miss the most critical period for pregnancy continuance. We examined the association between miscarriage and levels of maternal urinary cortisol during the first 3 weeks after conception. Pregnancies characterized by increased maternal cortisol during this period (within participant analyses) were more likely to result in spontaneous abortion (P < 0.05). This evidence links increased levels in this stress marker with a higher risk of early pregnancy loss in humans.

Knockdown of the tetraspan protein epithelial membrane protein-2 inhibits implantation in the mouse

The establishment of pregnancy requires a successful molecular interaction between the trophectoderm cells of the blastocyst stage embryo and the endometrial cells of the uterus. These interactions are complex and require synchronous development and coordinated endocrine, paracrine, and autocrine communication. In this study, we demonstrate that the tetraspan protein epithelial membrane protein-2 (EMP2) is involved in these molecular interactions during implantation. EMP2, which is highly expressed in the uterus, translocates from an intracellular location to the apical surface of the endometrial epithelium during the window of implantation and is expressed in decidualized stromal cells. We developed plasmid constructs that utilized either ribozyme-mediated or short hairpin RNA-mediated mechanisms to target endometrial EMP2 mRNA for destruction. These constructs were transfected into the mouse uterus on day 1 of pregnancy using the technique of in vivo reproductive tract gene transfer. Reduction in EMP2 expression by either method resulted in a significant decrease in the number of implantation sites in the treated uterine horns as compared to control horns. These studies indicate a previously unknown function of tetraspan proteins in implantation and could provide a molecular framework for the development of therapeutic modalities for both contraception and fertility.

Association Between Low Day 16 hCG and Miscarriage After Proven Cardiac Activity

OBJECTIVE

To investigate an association between low human chorionic gonadotrophin (hCG) levels at the end of the first week of implantation and later clinical miscarriage occurring after ultrasound confirmation of a live pregnancy.

METHODS

This was an observational retrospective study of 1,054 women who underwent in vitro fertilization and achieved an ultrasound-confirmed live singleton pregnancy with cardiac activity. The incidence of miscarriage diagnosed at 8-19 weeks +6 days of gestation was estimated in these 3 subgroups according to their hCG concentrations at day 16 after conception: less than the 25th, 25th-75th, and more than the 75th percentiles.

RESULTS

The overall incidence of miscarriage was 11.1% (117/1,054), and the median gestational age at diagnosis was 10 weeks and 4 days. The median (95% confidence interval) day 16 hCG level in the miscarriage group was 182 mIU/mL (157-211), significantly lower than the median level in those who had an ongoing pregnancy (223 mIU/mL [213-233], P < .003). There was an increasing risk of miscarriage associated with decreased hCG levels (8.0% at > 75th percentile; 9.9% at 25th-75th percentiles; 16.7% at < 25th percentile; P = .003).

CONCLUSION

Low hCG levels in very early pregnancy are associated with an increased risk of miscarriage occurring after the clinical recognition of pregnancy. The mechanisms underlying late first-trimester and second-trimester miscarriages may have begun as early as the first week of implantation.

LEVEL OF EVIDENCE

III.

Physiological adaptation in early human pregnancy: adaptation to balance maternal-fetal demands

After conception, the corpus luteum, placenta, and developing embryo release hormones, growth factors, and other substances into the maternal circulation. These substances trigger a cascade of events that transform the functioning of the maternal cardiovascular, respiratory, and renal systems, which in turn alter the physicochemical determinants of [H+]. Following implantation, maternal adaptations fulfill 4 important functions that support fetal growth. Increased availability of substrates and precursors for fetal-placental metabolism and hormone production is mediated by increases in dietary intake, as well as endocrine changes that increase the availability of glucose and low-density lipoprotein (LDL) cholesterol. Transport capacity is enhanced by increases in cardiac output, facilitating the transport of substrates and precursors to the placenta, and fetal waste products to maternal organs for disposal. Maternal-fetal exchange is regulated by the placenta after 10-12 weeks gestation, but it may occur through histiotrophic mechanisms before this time. Disposal of additional waste products (heat, carbon dioxide, and metabolic byproducts) occurs through peripheral vasodilation and increases in skin blood flow, ventilation, and renal filtration. The maternal physiological adaptations described above must meet the combined demands of maternal exercise and fetal growth. More research is needed to formulate evidence-based guidelines for healthy physical activity in early pregnancy.Key words: maternal adaptation, first trimester, exercise, fetal growth and development, hormones.

Integrin-linked kinase (ILK) is highly expressed in first trimester human chorionic villi and regulates migration of a human cytotrophoblast-derived cell line

The placenta represents a critically important fetal-maternal interaction. Trophoblast migration and invasion into the uterine wall is a precisely controlled process and aberrations in these processes are implicated in diseases such as preeclampsia. Integrin-linked kinase (ILK) is a multifunctional, cytoplasmic, serine/threonine kinase that has been implicated in regulating processes such as cell proliferation, survival, migration, and invasion; yet the temporal and spatial pattern of expression of ILK in human chorionic villi and its role in early human placental development are completely unknown. We hypothesized that ILK would be expressed in trophoblast subtypes of human chorionic villi during early placental development and that it would regulate trophoblast migration. Immunoblot analysis revealed that ILK protein was highly detectable in placental tissue samples throughout gestation. In floating branches of chorionic villi, from 6 to 15 wk of gestation immunofluorescence analysis of ILK expression in placental tissue sections demonstrated that ILK was highly detectable in the cytoplasm and membranes of villous cytotrophoblast cells and in stromal mesenchyme, whereas it was barely detectable in the syncytiotrophoblast layer. In anchoring branches of villi, ILK was highly localized to plasma membranes of extravillous trophoblast cells. Transient expression of dominant negative E359K-ILK in the villous explant-derived trophoblast cell line HTR8-SVneo dramatically reduced migration into wounds compared to cells expressing wild-type ILK or empty vector. Therefore, our work has demonstrated that ILK is highly expressed in trophoblast subtypes of human chorionic villi during the first trimester of pregnancy and is a likely mediator of trophoblast migration during this period of development.

Chemokine CXCL16, a scavenger receptor, induces proliferation and invasion of first-trimester human trophoblast cells in an autocrine manner

BACKGROUND

The aim of this study was to investigate whether CXCL16/CXCR6, a newly identified chemokine pair, is expressed in first-trimester human placenta and whether they affect the trophoblast cell biology, since we have found CXCR6 highly transcribed in first-trimester human trophoblast cells previously.

METHODS

We analysed the transcription and translation of CXCR6 and CXCL16 in purified first-trimester human trophoblast cells by real-time RT-PCR and immunochemical staining. We then examined the kinetic secretion of CXCL16 in the supernatant of primary-cultured trophoblast by enzyme-linked immunosorbent assay. We further investigated effects of CXCL16 on the proliferation and invasion of trophoblast cells in vitro.

RESULTS

We found the chemokine pair CXCL16/CXCR6 was transcribed and translated in first-trimester trophoblast cells and JAR line. In addition, the primary-cultured trophoblasts secreted CXCL16 spontaneously and continuously in 100-h culture. Treating trophoblasts with CXCL16 induced marked proliferation and invasion in vitro.

CONCLUSION

The findings from this study have demonstrated for the first time that CXCR6 and CXCL16 are co-expressed by first-trimester human trophoblast cells and stimulate their proliferation and invasion in an autocrine/paracrine manner. It suggests that CXCL16 plays important roles in human extravillous cytotrophoblast invasion and placentation.

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

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

Defective implantation and placentation: laying the blueprint for pregnancy complications

Normal implantation and placentation is critical for pregnancy success. Many pregnancy-related complications that present late in gestation (such as pre-eclampsia and preterm labour) appear to have their origins early in pregnancy with abnormalities in implantation and placental development. Implantation is characterized by invasion of the maternal tissues of the uterus by fetal trophoblast, and the degree to which trophoblast invades these tissues appears to be a major determinant of pregnancy outcome. Excessive invasion can lead to abnormally firm attachment of the placenta to the myometrium (placenta accreta) with increased maternal and perinatal morbidity. Inadequate invasion, specifically restricted endovascular invasion, has been implicated in the pathophysiology of such conditions as pre-eclampsia (gestational proteinuric hypertension), preterm premature rupture of membranes, preterm labour, and intrauterine growth restriction. The molecular and cellular mechanisms responsible for implantation remain enigmatic. This review will include an overview of implantation followed by a discussion of a number of molecular mechanisms implicated in defective implantation and placentation including the role of decidual prostaglandins and haemorrhage in regulating trophoblast invasion. An improved understanding of the molecular mechanisms responsible for abnormal implantation and placentation will likely improve clinicians' abilities to treat disorders that occur along this continuum, including infertility, recurrent pregnancy loss, pre-eclampsia, and preterm birth.

Murine implantation serine proteinases 1 and 2: Structure, function and evolution

Implantation is a vital phase in pregnancy whereupon the hatched embryo invades into the uterine wall to establish intimate contacts with the mother for further development. Although it is generally believed that proteinases are major factors that confer the embryo its invasive character, the nature of proteinases involved in implantation remain mostly elusive. In this article, we review the organization, structure and postulated function of the implantation serine proteinase (ISP1 and 2) genes. The ISPs are embedded within a cluster of tryptase genes on mouse chromosome 17. They are most closely related to members of the mast cell tryptase family, indicating that they may possess some properties characteristic of tryptases including multimerization-dependent activation. The significant similarities found in regulatory regions of ISP genes, together with the observation that ISP proteins are co-expressed and heterodimerize in the embryo and uterus suggests that they are intimately co-regulated during implantation. Inhibition of ISP proteolytic function has implicated this enzyme in the processes of embryo hatching and implantation.

Identification of endometrial genes regulated by early pregnancy, progesterone, and interferon tau in the ovine uterus

During early pregnancy in ruminants, progesterone (P4) from the corpus luteum and interferon tau (IFNT) from the conceptus act on the endometrium to regulate genes important for uterine receptivity and conceptus growth. The use of the uterine gland knockout (UGKO) ewe has demonstrated the critical role of epithelial secretions in regulation of conceptus survival and growth. A custom ovine cDNA array was used to identify alterations in gene expression of endometria from Day 14 cyclic, pregnant, and UGKO ewes (study 1) and from cyclic ewes treated with P4 or P4 with ZK 136,317 antiprogestin and control proteins or IFNT (study 2). In study 1, expression of 47 genes was more than 2-fold different between Day 14 pregnant and cyclic endometria, whereas 23 genes was different between Day 14 cyclic and UGKO endometria. In study 2, 70 genes were different due to P4 alone, 74 genes were affected by IFNT in a P4-dependent manner, and 180 genes were regulated by IFNT in a P4-independent manner. In each study, an approximately equal number of genes were found to be activated or repressed in each group. Endometrial genes increased by pregnancy and P4 and/or IFNT include B2M, CTSL, CXCL10, G1P3, GRP, IFI27, IFIT1, IFITM3, LGALS15, MX1, POSTN, RSAD2, and STAT5A. Transcripts decreased by pregnancy and P4 and/or IFNT include COL3A1, LUM, PTMA, PUM1, RPL9, SPARC, and VIM. Identification and analysis of these hormonally responsive genes will help define endometrial pathways critical for uterine support of peri-implantation conceptus survival, growth, and implantation.

Human trophoblast function during the implantation process

The implantation process involves complex and synchronized molecular and cellular events between the uterus and the implanting embryo. These events are regulated by paracrine and autocrine factors. Trophoblast invasion and migration through the uterine wall is mediated by molecular and cellular interactions, controlled by the trophoblast and the maternal microenvironment. This review is focused on the molecular constituents of the human trophoblast, their actions and interactions, including interrelations with the uterine endometrium.

The regulation of trophoblast differentiation by oxygen in the first trimester of pregnancy

In the first trimester of human pregnancy villous cytotrophoblasts are able to differentiate to form either the overlying syncytiotrophoblast layer or, in anchoring villi, extravillous trophoblasts which grow out from the villi and invade into the maternal decidua, acting to both physically attach the placenta to the decidua, and modify the maternal spiral arteries to sustain pregnancy. During the first 10-12 weeks of gestation, extravillous trophoblast plugs block the spiral arteries and prevent maternal blood flow entering the intervillous space, thereby creating an environment of physiological hypoxia in which placental and fetal development occur. As extravillous trophoblasts migrate away from the villus they differentiate from a proliferative to an invasive phenotype. The hypoxic environment of the first trimester is believed to play an important role in the regulation of trophoblast differentiation. However, there is currently a large body of conflicting experimental evidence concerning this topic. This review examines the experimental evidence to date on the role of oxygen in trophoblast differentiation.

Altered immunophenotypic parameters in infertile women. Possible role of herpes viremia

PROBLEM

Purpose of this study was to reveal any alteration in peripheral blood lymphocytic concentrations of a large cohort of infertile women and to investigate the possible role of herpes viremia in the peripheral immunostimulation.

METHOD OF STUDY

The immunophenotypic characteristics and the presence of herpes viruses DNA in the peripheral blood of 168 infertile women were studied.

RESULTS

Peripheral CD56+/CD16+ natural killer (NK) cell concentration, CD56+/CD16- NK cell concentration, white blood cell (WBC) concentration and lymphocyte concentration were statistically correlated to herpes viremia. Epstein-Barr virus (EBV) viremia is related with a limited reduction of CD56+/CD16- cell levels in the peripheral blood of infertile women with regard to the rest of herpes viruses. High T-lymphocyte concentration, CD4+ T-cell concentration and CD8+ T-cell concentration was observed in women positive for three different kinds of herpes viruses (triple viremia) in the peripheral blood.

CONCLUSIONS

Assuming that all women under study remained asymptomatic, these data suggest that subclinical herpesvirus viremia may be an important cause of peripheral immunostimulation in women with a history of infertility.

Uterine NK Cells Mediate Inflammation-Induced Fetal Demise in IL-10-Null Mice

Specialized NK cells are recruited in high numbers to the mammalian embryo implantation sites, yet remain pregnancy compatible. It is not well understood whether uterine NK (uNK) cells become adversely activated and mediate fetal demise, a common complication of early pregnancy. In this study we show that mating of IL-10(-/-) mice resulted in fetal resorption or intrauterine growth restriction in response to very low doses of LPS. Pregnancy in congenic wild-type mice was normal even at 10-fold higher LPS doses. Fetal resorption in IL-10(-/-) mice was associated with a significant increase in uNK cell cytotoxic activation and invasion into the placenta. Depletion of uNK cells, TNF-alpha neutralization, or IL-10 administration rescued pregnancy in LPS-treated IL-10(-/-) animals. Our results identify an immune mechanism of fetal demise involving IL-10 deficiency, NK cells, and inflammation. These results may provide insight into adverse pregnancy outcomes in humans.

In vivo infusion of interleukin-1beta and chorionic gonadotropin induces endometrial changes that mimic early pregnancy events in the baboon

Both human chorionic gonadotropin (hCG) and IL-1beta induce changes in the endometrium that are associated with the establishment of pregnancy. We investigated the synergistic effect of these two embryonic signals on endometrial function using a baboon model of simulated pregnancy. Recombinant hCG (30 IU/d) was infused between d 6 and 10 post ovulation (PO) to mimic blastocyst transit. On the expected day of implantation (d 10 PO), IL-1beta (12 ng/d) or IL-1 receptor antagonist (IL-1Ra; 12 ng/d) was infused for an additional 5 d. Endometria were harvested on d 15 PO. Both hCG and hCG plus IL-1beta induced marked differences in the distribution of alpha-smooth muscle actin, proliferation marker Ki67, decidualization marker IGF-binding protein-1, and cyclooxygenase-1. The most marked effect of IL-1beta was the induction of IGF-binding protein-1 protein in stromal cells close to the apical surface, whereas cyclooxygenase-1 was down-regulated in the glandular epithelium. Protein arrays of uterine flushings showed significant suppression of death receptors, Fas and TNF receptor 1, in the hCG- with or without IL-1beta-treated groups, suggesting an inhibition of apoptosis. Additionally, cytotoxic T lymphocyte antigen-4, matrix metalloproteinase-3, and IL-4 were suppressed in treated animals compared with controls. However, no differences were observed in cytokine profile between hCG-treated and hCG- plus IL-1beta-treated baboons. This study confirms that in preparation for pregnancy, the primate endometrium undergoes both morphological and functional changes, which are modulated by hCG and IL-1beta, that lead to the inhibition of apoptosis and the development of an immunotolerant environment. These changes suggest that infusion of IL-1beta at the time of implantation into the nonpregnant baboon treated with hCG synergizes with hCG and mimics the early endometrial events associated with the presence of an embryo.