The paracrinology of tubal ectopic pregnancy

Dysregulation of TMEM16A impairs oviductal transport of embryos

Ectopic pregnancy is an acute abdominalgia in obstetrics and gynecology, especially in fallopian tubal pregnancy. The ion channel protein transmembrane protein 16A (TMEM16A) is widely distributed in various tissues, even in the oviduct. In this study, we showed that TMEM16A was expressed in the human fallopian tube and was upregulated in patients with tubal pregnancy. By measuring isolated fallopian tube tissues, we found that TMEM16A was involved in regulating not only the contraction of muscle strips but also the beat frequency of cilia. In addition, pharmacological activation or inhibition of TMEM16A could lead to retention of embryos in oviducts. Moreover, the embryos in oviducts were delayed in development and some of them had malformations and deletions. The total number of embryos in the oviducts and uterus was significantly less than that of the control group. Furthermore, we detected changes in the level of m6A methylation, where the relevant writers and readers were reduced in tubal tissues from tubal pregnancies. In m6A mRNA methylation, writers catalyze the addition of methyl groups to cytosine residues and readers bind to the methyl groups and affect gene translation. In human fallopian tube epithelial cell line FTE187, we found that interference with methyltransferase 3 (METTL3) expression increased TMEM16A, suggesting that TMEM16A might be regulated by m6A methylation. In general, our study revealed a novel regulatory point for embryo transport and development, introducing a new role for the diagnosis and treatment of tubal pregnancy.NEW & NOTEWORTHY The ion channel protein TMEM16A is expressed in the epithelium and smooth muscle of the human fallopian tube and is upregulated in patients with tubal pregnancy. TMEM16A is involved in regulating the smooth muscle contraction and the cilia beating. Dysregulated TMEM16A may result in embryo retention in the oviduct and delayed early embryo development. Our study reveals a new regulatory point for embryo transport and development.

Exploring the presence of markers of decidualization in the fallopian tubes: a systematic review

The fallopian tubes (FTs) are part of the female upper genital tract. The healthy FT provides the biological environment for successful fertilization and facilitates the subsequent movement of the conceptus to the endometrial cavity. However, when the FT is damaged, as with salpingitis, pyosalpinx, and hydrosalpinx, it may increase the risk of an ectopic pregnancy, a life-threatening condition. Decidualization refers to a multifactorial process by which the endometrium changes to permit blastocyst implantation. The decidualization reaction is vital for endometrial receptivity during the window of implantation. To date, no comprehensive review that collates evidence on decidualization in the human FT has been conducted. Therefore, the aim of this review is to compile the current evidence on cellular decidualization occurring in the healthy and pathological FT in women of reproductive age. A literature search was conducted using five databases and identified 746 articles, 24 of which were analyzed based on inclusion and exclusion criteria. The available evidence indicates that the FT are able to undergo decidual changes under specific circumstances; however, the exact mechanism by which this occurs is poorly understood. Further research is needed to elucidate the mechanism by which decidualization can occur in the FT.

The Effect of Altered Mucin1, FGF2, and HBEGF Gene Expression at The Ectopic Implantation Site and Endometrial Tissues in The Tubal Pregnancy Pathogenesis: A Case-Control Study

BACKGROUND

Ectopic pregnancy (EP) is defined as implantation and development of an embryo outside of the uterine tissue. Women undergoing assisted reproductive technologies (ART), particularly frozen embryo transfer (FET), are in high-risk populations for EP. Mucin1 (MUC1), fibroblast growth factor-2 (FGF2), and Heparin-binding epidermal growth factor (HBEGF) genes are involved in the endometrial receptivity pathway, leading to normal eutopic implantation; Although, their relevance in the tubal pregnancy after FET is unknown. We aimed evaluation of Mucin1, FGF2, and HBEGF expression fold as endometrial receptive markers in the EP patients following the FET cycle.

MATERIALS AND METHODS

A case-control study was conducted on ten patients (five EP patients and five women in the pseudo-pregnancy group, as the control samples). Pseudo-pregnancy group was established in women who were candidates for hysterectomy for benign diseases. Fallopian tube biopsies and corresponding endometrial tissues from these patients were taken during the hysterectomy. However, the fallopian tube and endometrial tissues of EP patients were obtained during salpingectomy. The mRNA expressions of Mucin1, FGF2, and HBEGF genes in the fallopian tube and endometrial tissues were measured by real-time polymerase chain reaction (PCR) assay.

RESULTS

MUC1 mRNA expression level in the endometrium of the case group was higher than in the control group (P=0.04); however, its mRNA expression in the fallopian samples of the case group in comparison with the control group was significantly decreased (P=0.001). The HBEGF mRNA expression level was not significantly different between the case and control endometrium, whereas its expression was significantly increased in the case fallopian samples compared with the control ones (P=0.001). The same pattern was observed for FGF2 mRNA expression level in the fallopian samples of the case group but was significantly reduced in the endometrial samples in comparison with the control samples (P=0.03).

CONCLUSION

Mucin1, FGF2, and HBEGF gene mRNA expression changes may explain the embryo rejection from the uterus and the establishment of a receptive phenotype in fallopian cells.

Comparison of the application value of transvaginal ultrasound and transabdominal ultrasound in the diagnosis of ectopic pregnancy

BACKGROUND

Ectopic pregnancy (EP) is one of the most common acute abdominal diseases in gynecology. Once the condition of EP is delayed, it may lead to massive hemorrhage, shock, and even death in a short time, seriously threatening the patient’s life. Early diagnosis is the key to preventing and improving the prognosis of EP. Transabdominal ultrasound (TAS) and transvaginal ultrasound (TVS) are the main diagnostic methods for abdominal diseases. The purpose of this study is to explore the application value and effect of TAS and TVS in the diagnosis of EP, hoping to provide more valuable references for the diagnosis of EP.

AIM

To explore the application value of TAS and TVS in the diagnosis of EP and to improve the level of clinical diagnosis.

METHODS

A total of 140 patients with EP admitted to our hospital from July 2018 to July 2020 were selected for this study. All patients were divided into two groups according to the examination methods. 63 patients who underwent abdominal ultrasound examination were set as the TAS group, while 77 patients who underwent TVS examination were set as the TVS group. We compared the diagnostic accuracy and misdiagnosis rates between the two types of ultrasound examinations, as well as the postoperative pathological results of the two diagnostic methods for different types of ectopic pregnancies. We also analyzed the sonograms for the presence of mixed ectopic masses, adnexal masses, ectopic gestational sacs, the presence or absence of visible embryo and fetal heart in the ectopic sac shadow, and the detection of fluid in the rectal fossa of the uterus, such as the adnexal area, yolk sac, and embryo, etc. In addition, the diagnosis time, days of gestational sac appearance, operation time, endometrial thickness, and blood flow resistance index were compared as well.

RESULTS

After performing both types of ultrasound examinations in 140 patients with EP, we found that the diagnostic accuracy of TVS was significantly higher than that of TAS, and the misdiagnosis rate was significantly lower than that of TAS. The differences were statistically significant (P < 0.05). In addition, the detection rate of TVS was better than that of TAS for the presence of mixed masses, adnexal masses, ectopic gestational sacs, the presence or absence of visible embryo and fetal heart in the shadow of the ectopic sac, and sonograms such as the adnexal area, yolk sac, and embryo, etc. The coincidence rate of its postoperative pathological examination results was significantly higher than those of TAS. The diagnosis time and the days of gestational sac appearance by TVS were significantly shorter than that by TAS, and the operation time was earlier than that by TAS. What’s more, the detection rates of the endometrial thickness £ 1.5 mm and blood flow resistance £ 0.5 were significantly higher in TVS diagnosis of EP than in TAS. All differences were statistically significant (P < 0.05).

CONCLUSION

Compared with TAS, TVS has the advantages of high detection accuracy and good sonogram performance.

Mechanism of Human Tubal Ectopic Pregnancy Caused by Cigarette Smoking

In the past few decades, the smoking rate of women of childbearing age has increased. Epidemiological data has repeatedly shown that smoking women have an increased risk of various reproductive diseases, including ectopic pregnancy (EP), decreased fertility, adverse pregnancy outcomes, and failure of assisted reproduction. The oviduct was the target of cigarette smoke in many in vivo and in vitro studies. The fallopian tube is a well-designed organ. Its function is to collect and transport the ova to the fertilized site and provide a suitable environment for fertilization and early embryonic development. Lastly, the fallopian tube transports the pre-implantation embryo to the uterus. Various biological processes can be studied in the fallopian tubes, making it an excellent model for toxicology. This paper reviews the roles of the fallopian tube in gametes and embryo transportation, and the possible mechanism tobacco smoke contributes to tubal EP. A possible signal pathway might be a model to develop intervention of EP for pregnant women exposed to smoking.

Molecular Mechanisms Underlying the Association between Endometriosis and Ectopic Pregnancy

Endometriosis is a common inflammatory disease characterized by the presence of endometrial cells outside the uterine cavity. It is estimated that it affects 10% of women of reproductive age. Its pathogenesis covers a wide range of abnormalities, including adhesion, proliferation, and cell signaling disturbances. It is associated with a significant deterioration in quality of life as a result of chronic pelvic pain and may also lead to infertility. One of the most serious complications of endometriosis is an ectopic pregnancy (EP). Currently, the exact mechanism explaining this phenomenon is unknown; therefore, there are no effective methods of prevention. It is assumed that the pathogenesis of EP is influenced by abnormalities in the contraction of the fallopian tube muscles, the mobility of the cilia, and in the fallopian microenvironment. Endometriosis can disrupt function on all three levels and thus contribute to the implantation of the embryo beyond the physiological site. This review takes into account aspects of the molecular mechanisms involved in the pathophysiology of endometriosis and EP, with particular emphasis on the similarities between them.

Lgr4 Regulates Oviductal Epithelial Secretion Through the WNT Signaling Pathway

The WNT signaling pathway plays a crucial role in oviduct/fallopian development. However, the specific physiological processes regulated by the WNT pathway in the fallopian/oviduct function remain obscure. Benefiting from the Lgr4 knockout mouse model, we report the regulation of oviduct epithelial secretion by LGR4. Specifically, the loss of Lgr4 altered the mouse oviduct size and weight, severely reduced the number of oviductal epithelial cells, and ultimately impaired the epithelial secretion. These alterations were mediated by a failure of CTNNB1 protein accumulation in the oviductal epithelial cytoplasm, by the modulation of WNT pathways, and subsequently by a profound change of the gene expression profile of epithelial cells. In addition, selective activation of the WNT pathway triggered the expression of steroidogenic genes, like Cyp11a1 and 3β-Hsd1, through the activation of the transcriptional factor NR5A2 in an oviduct primary cell culture system. As demonstrated, the LGR4 protein modulates a WNT-NR5A2 signaling cascade facilitating epithelial secretory cell maturation and steroidogenesis to safeguard oviduct development and function in mice.

Relation of Chlamydia trachomatis infections to ectopic pregnancy: A meta-analysis and systematic review

BACKGROUND

In a multitude of previous studies, Chlamydia trachomatis (CT) plays an important role in the occurrence of ectopic pregnancy (EP). However, the predictive value of CT infections in the occurrence of EP has not been estimated worldwide. We thus evaluated, by means of a meta-analysis, the current status of the association between CT infections with EP and the potential predictive value of CT infections in EP.

METHODS

We evaluated studies performed between the database construction time and August 2018 published in PubMed, the Cochrane Library, EMBASE, and the Web of Science (SCI). The relationship between CT and EP was calculated based upon the predetermined entry criteria for control group selection and the original data. The related articles were analyzed using a random-effects model, and the heterogeneity of the studies was assessed using the I index. Data were analyzed with the STATA 12.0 software.

RESULTS

Twenty-five studies that recruited 11960 patients were included in the present meta-analysis, and the relation of CT infections with EP were assessed. The association between CT infections and EP risk showed an odds ratio (OR) of 3.03, with a 95% confidence interval (CI) of 2.37 to 3.89. Our results showed that there was a statistically significant difference between the intervention and control groups. The prevalence of CT infections in EP was then calculated by a subgroup analysis: African (OR, 2.22; 95% CI, 1.14-4.31), European (OR, 3.16; 95% CI, 2.10-4.47), North American (OR, 3.07; 95% CI, 1.78-5.31), and Asian (OR, 3.39; 95% CI, 1.95-5.90).

CONCLUSIONS

From the results of numerous studies conducted on different continents, this meta-analysis showed a clear association between EP and prior CT infections, that is, CT infections increase the risk of EP occurrence.

Interstitial Pregnancy after Ipsilateral Salpingectomy: Analysis of 46 Cases and a Literature Review

STUDY OBJECTIVE

To investigate the relationship between previous ipsilateral salpingectomy and interstitial pregnancy and report on our experience of laparoscopic cornuostomy for interstitial pregnancy.

DESIGN

Single-center, retrospective review.

SETTING

University-based hospital.

PATIENTS

All patients who had undergone ipsilateral salpingectomy previously, diagnosed with interstitial pregnancy and treated between July 2010 and September 2018.

INTERVENTIONS

Laparoscopy or laparotomy as a treatment for interstitial pregnancy after ipsilateral salpingectomy.

MEASUREMENTS AND MAIN RESULTS

A total of 414 cases of interstitial pregnancy were identified, of which 46 (11.1%) were after ipsilateral salpingectomy. Of the 46 patients, 20 (43.5%) became pregnant by in vitro fertilization and embryo transfer. Ipsilateral salpingectomy was the result of an ectopic pregnancy in 40 patients, hydrosalpinx in 5 patients, and torsion of an ovarian tumor in 1 patient. The laparoscopic approach was used to treat 78.3% of patients with history of previous salpingectomy. Patients who underwent ipsilateral salpingectomy by laparoscopy previously had a shorter interval from salpingectomy to interstitial pregnancy (24 months vs 60 months; p = .038) compared with patients who underwent ipsilateral salpingectomy by laparotomy. Laparoscopic cornuostomy was performed in 38 patients (82.6%); 12 had fetal cardiac activity, 15 had ruptured masses, and 16 used prophylactic methotrexate (MTX) intraoperatively. The median size of the ectopic mass was 2.5 cm (1.0-5.0 cm). At the time of laparoscopic cornuostomy, more patients with interstitial pregnancies with intact ectopic masses were administered prophylactic MTX (81.3% vs 45.5%; p = .043). Only 1 patient with a ruptured ectopic mass, high preoperative human chorionic gonadotropin levels, and without prophylactic MTX administration experienced a persistent ectopic pregnancy.

CONCLUSION

Patients with a history of ipsilateral salpingectomy should be cautioned regarding the possibility of interstitial pregnancy. Laparoscopic cornuostomy appears to be an appropriate treatment for interstitial pregnancy in patients wishing to preserve fertility, and the use of concomitant prophylactic MTX may reduce the risk of persistent ectopic pregnancy, especially in patients with ruptured masses and high human chorionic gonadotropin levels.

The estrogen-macrophage interplay in the homeostasis of the female reproductive tract

BACKGROUND

Estrogens are known to orchestrate reproductive events and to regulate the immune system during infections and following tissue damage. Recent findings suggest that, in the absence of any danger signal, estrogens trigger the physiological expansion and functional specialization of macrophages, which are immune cells that populate the female reproductive tract (FRT) and are increasingly being recognized to participate in tissue homeostasis beyond their immune activity against infections. Although estrogens are the only female gonadal hormones that directly target macrophages, a comprehensive view of this endocrine-immune communication and its involvement in the FRT is still missing.

OBJECTIVE AND RATIONALE

Recent accomplishments encourage a revision of the literature on the ability of macrophages to respond to estrogens and induce tissue-specific functions required for reproductive events, with the aim to envision macrophages as key players in FRT homeostasis and mediators of the regenerative and trophic actions of estrogens.

SEARCH METHODS

We conducted a systematic search using PubMed and Ovid for human, animal (rodents) and cellular studies published until 2018 on estrogen action in macrophages and the activity of these cells in the FRT.

OUTCOMES

Our search identified the remarkable ability of macrophages to activate biochemical processes in response to estrogens in cell culture experiments. The distribution at specific locations, interaction with selected cells and acquisition of distinct phenotypes of macrophages in the FRT, as well as the cyclic renewal of these properties at each ovarian cycle, demonstrate the involvement of these cells in the homeostasis of reproductive events. Moreover, current evidence suggests an association between estrogen-macrophage signaling and the generation of a tolerant and regenerative environment in the FRT, although a causative link is still missing.

WIDER IMPLICATIONS

Dysregulation of the functions and estrogen responsiveness of FRT macrophages may be involved in infertility and estrogen- and macrophage-dependent gynecological diseases, such as ovarian cancer and endometriosis. Thus, more research is needed on the physiology and pharmacological control of this endocrine-immune interplay.

An in vitro investigation of telocytes-educated macrophages: morphology, heterocellular junctions, apoptosis and invasion analysis

BACKGROUND

Telocytes (TCs), a recently discovered novel type of interstitial cells, were also found in a wide variety of human and mammalian reproductive organs/tissues, including uterus, oviduct and placenta. Previously, we demonstrated that TCs-conditioned media was capable of activating peritoneal macrophages (pMACs) through paracrine effects. This study investigates the hypothesis that direct interaction of TCs with pMACs will also play a significant role in immunoregulation of pMACs.

METHODS

TCs and pMACs were derived from the uterus and intraperitoneal cavity of female BALB/c mice, respectively. TCs were identified by immunofluorescence and then co-cultured directly with pMACs for 24 h without added cytokines, to observe the in vitro biological behavior of pMACs. We used histochemical staining to study morphology and mitochondrial metabolism of pMACs, scanning electron microscopy to study heterocellular junctions, flow cytometry to investigate mitochondrial membrane potential (ΔΨm) and apoptosis, and transwell chambers to study invasion ability. Student-t test was used accordingly.

RESULTS

Presently, TCs with typical structure and immunophenotype of double CD-34-positive/vimentin-positive were successfully isolated. pMACs co-cultured with TCs showed obviously morphological activation, with enhanced energy metabolism (P < 0.05). Meanwhile, direct physical cell-to-cell interaction promoted the development of heterocellular junctions between TCs and pMACs. Furthermore, TCs treatment markedly reduced the depletion of ΔΨm in co-cultured pMACs (all P < 0.05), and inhibited their apoptosis (P < 0.05). Functionally, pMACs co-cultured with TCs showed enhanced invasion ability (P < 0.05).

CONCLUSIONS

Direct physical cell-to-cell interaction promoted the development of heterocellular junctions between TCs and pMACs, presumably responsible for the observed novel efficient way of pMACs activation via mitochondrial signaling pathway. TCs-educated pMACs might be a promising way to restore the defective immunosurveillance in endometriosis (EMs), led to the enhanced treatment efficacy of EMs in a simple and clinically feasible fashion.

Prioritization of Susceptibility Genes for Ectopic Pregnancy by Gene Network Analysis

Ectopic pregnancy is a very dangerous complication of pregnancy, affecting 1%–2% of all reported pregnancies. Due to ethical constraints on human biopsies and the lack of suitable animal models, there has been little success in identifying functionally important genes in the pathogenesis of ectopic pregnancy. In the present study, we developed a random walk–based computational method named TM-rank to prioritize ectopic pregnancy–related genes based on text mining data and gene network information. Using a defined threshold value, we identified five top-ranked genes: VEGFA (vascular endothelial growth factor A), IL8 (interleukin 8), IL6 (interleukin 6), ESR1 (estrogen receptor 1) and EGFR (epidermal growth factor receptor). These genes are promising candidate genes that can serve as useful diagnostic biomarkers and therapeutic targets. Our approach represents a novel strategy for prioritizing disease susceptibility genes.

Effects of adrenomedullin on the expression of inflammatory cytokines and chemokines in oviducts from women with tubal ectopic pregnancy: an in-vitro experimental study

BACKGROUND

The occurrence of tubal ectopic pregnancy (tEP) is related to the inflammation of the oviduct. Recently, Adrenomedullin (ADM) was found highly expression in human oviduct. The current study is to investigate whether ADM have a modulatory action on inflammatory cytokines and chemokines in oviductal tissue from women with tubal ectopic pregnancy (tEP).

METHODS

Oviductal isthmus samples were collected from women with tEP undergoing salpingectomy, and women undergoing hysterectomy for benign gynaecological conditions. The mRNA and protein levels of inflammatory cytokines/chemokines were assayed by PCR (n = 6 for tEP, n = 5 for controls) and protein microarray methods (n = 5 for both tEP and controls) respectively.

RESULTS

Some of the inflammatory cytokines/chemokines were upregulated by ADM in oviducts from tEP patients at both mRNA and protein levels. Incubation of oviduct from tEP patients with ADM for 24 h down-regulated some of these cytokines/chemokines.

CONCLUSION

Our results suggest an additional mechanism whereby ADM insufficiency may increase the susceptibility to tEP through diminished anti-inflammatory activity. The actual impact of the relationship between ADM and inflammatory process on tubal implantation needs further exploration.

Incidence, diagnosis and management of tubal and nontubal ectopic pregnancies: a review

BACKGROUND

Ectopic pregnancy is a potentially life-threatening condition occurring in 1-2 % of all pregnancies. The most common ectopic implantation site is the fallopian tube, though 10 % of ectopic pregnancies implant in the cervix, ovary, myometrium, interstitial portion of the fallopian tube, abdominal cavity or within a cesarean section scar.

FINDINGS

Diagnosis involves a combination of clinical symptoms, serology, and ultrasound. Medical management is a safe and effective option in most clinically stable patients. Patients who have failed medical management, are ineligible, or present with ruptured ectopic pregnancy or heterotopic pregnancy are most often managed with excision by laparoscopy or, less commonly, laparotomy. Management of nontubal ectopic pregnancies may involve medical or surgical treatment, or a combination, as dictated by ectopic pregnancy location and the patient's clinical stability. Following tubal ectopic pregnancy, the rate of subsequent intrauterine pregnancy is high and independent of treatment modality.

CONCLUSION

This review describes the incidence, risk factors, diagnosis, and management of tubal and non-tubal ectopic and heterotopic pregnancies, and reviews the existing data regarding recurrence and future fertility.

Molecular Regulation of Parturition: The Role of the Decidual Clock

The timing of birth is a critical determinant of perinatal outcome. Despite intensive research, the molecular mechanisms responsible for the onset of labor both at term and preterm remain unclear. It is likely that a "parturition cascade" exists that triggers labor at term, that preterm labor results from mechanisms that either prematurely stimulate or short-circuit this cascade, and that these mechanisms involve the activation of proinflammatory pathways within the uterus. It has long been postulated that the fetoplacental unit is in control of the timing of birth through a "placental clock." We suggest that it is not a placental clock that regulates the timing of birth, but rather a "decidual clock." Here, we review the evidence in support of the endometrium/decidua as the organ primarily responsible for the timing of birth and discuss the molecular mechanisms that prime this decidual clock.

Pathogenesis of fallopian tube damage caused by Chlamydia trachomatis infections

Chlamydia trachomatis is the leading cause of bacterial sexually transmitted disease worldwide resulting in 4-5 million new cases of Chlamydia annually and an estimated 100 million cases per annum. Infections of the lower female genital tract (FGT) frequently are asymptomatic; thus, they often remain undiagnosed or untreated. If infections are either not resolved or left untreated, chlamydia can ascend to the upper FGT and infect the fallopian tubes (FTs) causing salpingitis that may lead to functional damage of the FTs and tubal factor infertility (TFI). Clinical observations and experimental data have indicated a role for antibodies against C. trachomatis proteins such as the 60-kDa heat shock protein 60 (cHSP60) in the immunopathogenesis of TFI. When released from infected cells, cHSP60 can induce proinflammatory immune responses that may functionally impair the FTs leading to fibrosis and luminal occlusion. Chlamydial pathogenesis of irreversible and permanent tubal damage is a consequence of innate and adaptive host immune responses to ongoing or repeated infections. The extracellular matrix that is regulated by metalloproteinases may also be modified by chlamydial infections of the FGT. This review will highlight protective and pathogenic immune responses to ongoing and repeated chlamydial infections of the FGT. It will also present two recent hypotheses to explain mechanisms that may contribute to FT damage during a C. trachomatis infection. If Chlamydia immunopathology can be controlled, it might yield a method of inducing fibrosis and thus provide a means of nonsurgical permanent contraception for women.

Role of Chlamydia trachomatis and emerging Chlamydia-related bacteria in ectopic pregnancy in Vietnam

In this case-control study, we investigated the seroprevalence and molecular evidence of Chlamydia trachomatis and Waddlia chondrophila in ectopic pregnancies (EP) and uneventful control pregnancies in 343 women from Vietnam. Whereas presence of C. trachomatis IgG was strongly associated with EP [adjusted odds ratio (aOR) 5·41, 95% confidence interval (CI) 2·58-11·32], its DNA remained undetected in all tubal lesions. We confirmed an independent association between antibodies against Waddlia and previous miscarriage (aOR 1·87, 95% CI 1·02-3·42). Further investigations are needed to understand the clinical significance of Waddlia's high seroprevalence (25·9% in control pregnancies) in this urban population.

Role of activins in embryo implantation and diagnosis of ectopic pregnancy: a review

Embryo implantation is a major prerequisite for the successful establishment of pregnancy. Ectopic implantation outside the intrauterine cavity and the development of ectopic pregnancy (EP) is a major cause of maternal morbidity and occasionally mortality during the first trimester. EP may be induced by failure of tubal transport and/or increased tubal receptivity. Activins, their type II receptors and follistatin have been localised in the human endometrial and tubal epithelium and they are major regulators of endometrial and tubal physiology during the menstrual cycle. Pathological expression of activins and their binding protein, follistatin, was observed in tissue and serum samples collected from EP. Several studies with different designs investigated the diagnostic value of a single measurement of serum activin-A in the differentiation between normal intrauterine and failing early pregnancy and the results are controversial. Nevertheless, the diagnostic value of activins in EP, including the other activin isoforms (activin-B and -AB) and follistatin, merits further research. This review appraises the data to date researching the role of activins in the establishment of normal pregnancy and, pathogenesis and diagnosis of tubal EP.

Hypothyroidism affects differentially the cell size of epithelial cells among oviductal regions of rabbits

Oviductal regions show particular histological characteristics and functions. Tubal pathologies and hypothyroidism are related to primary and secondary infertility. The impact of hypothyroidism on the histological characteristics of oviductal regions has been scarcely studied. Our aim was to analyse the histological characteristics of oviductal regions in control and hypothyroid rabbits. Hypothyroidism was induced by oral administration of methimazole (MMI) for 30 days. For both groups, serum concentrations of thyroid and gonadal hormones were determined. Sections of oviductal regions were stained with the Masson's trichrome technique to analyse both epithelial and smooth muscle layers. The percentage of proliferative epithelial cells (anti-Ki67) in diverse oviductal regions was also quantified. Data were compared with Student t-test, Mann-Whitney U-test, or Fischer's test. In comparison with the control group, the hypothyroid group showed: (i) a low concentration of T3 and T4, but a high level of TSH; (ii) similar values of serum estradiol, progesterone and testosterone; (iii) a large size of ciliated cells in the ampulla (AMP), isthmus (IST) and utero-tubal junction (UTJ); (iv) a large size of secretory cells in the IST region; (v) a low percentage of proliferative secretory cells in the fimbria-infundibulum (FIM-INF) region; and (vi) a similar thickness of the smooth muscle layer and the cross-sectional area in the AMP and IST regions. Modifications in the size of the oviductal epithelium in hypothyroid rabbits could be related to changes in the cell metabolism that may impact on the reproductive functions achieved by oviduct.

MicroRNA and implantation

We provide a review of microRNA (miRNA) related to human implantation which shows the potential diagnostic role of miRNAs in impaired endometrial receptivity, altered embryo development, implantation failure after assisted reproduction technology, and in ectopic pregnancy and pregnancies of unknown location. MicroRNAs may be emerging diagnostic markers and potential therapeutic tools for understanding implantation disorders. However, further research is needed before miRNAs can be used in clinical practice for identifying and treating implantation failure.

The onset of human ectopic pregnancy demonstrates a differential expression of miRNAs and their cognate targets in the Fallopian tube

Human ectopic pregnancy (EP) is a leading cause of pregnancy-related death, but the molecular basis underlying the onset of tubal EP is largely unknown. Female Dicer1 conditional knockout mice are infertile with dysfunctional Fallopian tube and have a different miRNA expression profile compared to wild-type mice, and we speculated that Dicer-mediated regulation of miRNA expression and specific miRNA-controlled targets might contribute to the onset of tubal EP. In the present study, we used microarray analysis and quantitative RT-PCR to examine the expression of miRNAs and core miRNA regulatory components in Fallopian tube tissues from women with EP. We found that the levels of DICER1, four miRNAs (let-7i, miR-149, miR-182, and miR-424), and estrogen receptor α distinguished the tubal implantation site from the non-implantation site. Computational algorithms and screening for interactions with the estrogen and progesterone receptor signaling pathways showed that the four miRNAs were predicted to target ten genes, including NEDD4, TAF15, and SPEN. Subsequent experiments showed differences in NEDD4 mRNA and protein levels between the implantation and non-implantation sites. Finally, we revealed that increases in smooth muscle cell NEDD4 and stromal cell TAF15, in parallel with a decrease in epithelial cell SPEN, were associated with tubal implantation. Our study suggests that changes in miRNA levels by the DICER-mediated miRNA-processing machinery result in aberrant expression of cell type-specific proteins that are potentially involved in the onset of tubal EP.

The expression of IL-6Rα and Gp130 in fallopian tubes bearing an ectopic pregnancy

Women with tubal ectopic pregnancies have high levels of circulating interleukin 6 (IL-6). IL-6 treatment in vitro significantly reduces the ciliary activity of tubal epithelium. The effects of IL-6 on target cells occur via the formation of a high-affinity complex with its receptors IL-6Rα and glycoprotein 130 (Gp130). IL-6Rα is specifically expressed in the cilia of the epithelial cells. In this study, we performed a quantitative reverse transcriptase polymerase chain reaction to determine the mRNA expression of IL-6Rα and Gp130 in the fallopian tubes obtained from 12 women with ectopic pregnancies, 12 women with normal pregnancies, and 12 healthy nonpregnant women in the luteal phase of their menstrual cycle. Fallopian tubes were evaluated from specimens taken during tubal ligation in normal pregnancies and nonpregnant fertile women or during tubal surgery in ectopic pregnancies. We observed that IL-6Rα mRNA expression in fallopian tubes was increased in ectopic pregnancy compared with that in the midluteal phase. We also found that the Gp130 mRNA expression was significantly lower in fallopian tubes from ectopic pregnancies than in those from nonpregnant women during the midluteal phase of their menstrual cycle, although its expression was noticeably high in fallopian tubes in the midluteal phase, which suggests that high Gp130 levels may possibly contribute to embryo transport into the uterus.

Expressions of candidate molecules in the human fallopian tube and chorionic villi of tubal pregnancy exposed to levonorgestrel emergency contraception

BACKGROUND

Cases of ectopic pregnancy (EP) following levonorgestrel (LNG) emergency contraception (EC) failure were reported, however, the effects of LNG on tubal microenvironment or chorionic villi in EP have not yet been documented.

METHODS

Fifty-five women with tubal pregnancy were divided into two groups according to whether LNG-EC was administrated during the cycle of conception. The serum concentrations of beta-hCG, E2 and P were measured. The mRNA and protein expressions of estrogen and progesterone receptors, leukemia inhibitory factor, vascular endothelial growth factor, inducible nitric oxide synthase, and endocannabinoid receptor - CB1 in the ectopic implantation site and chorionic villi were examined.

RESULTS

Compared to those unexposed to LNG-EC, women with tubal pregnancy exposed to LNG-EC during the cycle of conception had no statistically significances in the serum concentrations of beta-hCG, E2 P, nor in the pathological types of tubal pregnancy or the expressions of ER-alpha, PR, LIF, VEGF, iNOS and CB1.

CONCLUSIONS

The expressions of candidate molecules in the fallopian tube and chorionic villi were not altered by exposure to LNG-EC. A routine therapy with no additional intervention might thus be applied to tubal pregnancy exposed to LNG-EC.

Linking DNA methylation to the onset of human tubal ectopic pregnancy

Ectopic pregnancy is a common reproductive disorder of unknown etiology and is a leading cause of maternal and fetal mortality. Because of the asymptomatic nature of early tubal ectopic pregnancy and the lack of specific biomarkers for early diagnosis, a better understanding of the complex cellular and molecular interactions that contribute to tubal ectopic pregnancy is required. DNA methylation is the most studied epigenetic process in various tissues and cells, and the goal of this article is to provide a brief review of recent work describing the potential mechanisms of DNA methylation and the biological function of such methylation in normal intrauterine pregnancy. Further, novel findings from our laboratory highlight the possible role of DNA methylation in human Fallopian tube dysfunction and suggest a possible correlation between methylation of estrogen receptor α in women and the occurrence of tubal ectopic pregnancies.

Biomarkers for ectopic pregnancy and pregnancy of unknown location

Early pregnancy failure is the most common complication of pregnancy, and 1% to 2% of all pregnancies will be ectopic. As one of the leading causes of maternal morbidity and mortality, diagnosing ectopic pregnancy and determining the fate of a pregnancy of unknown location are of great clinical concern. Several serum and plasma biomarkers for ectopic pregnancy have been investigated independently and in combination. The following is a review of the state of biomarker discovery and development for ectopic pregnancy and pregnancy of unknown location.

From mice to women and back again: causalities and clues for Chlamydia-induced tubal ectopic pregnancy

OBJECTIVE

To provide an overview of knockout mouse models that have pathological tubal phenotypes after Chlamydia muridarum infection, discuss factors and pathological processes that contribute to inflammation, summarize data on tubal transport and progression of tubal implantation from studies in humans and animal models, and highlight research questions in the field.

DESIGN

A search of the relevant literature using PubMed and other online tools.

SETTING

University-based preclinical and clinical research laboratories.

PATIENT(S)

Women with tubal ectopic pregnancy after Chlamydia trachomatis infection.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Critical review of the literature.

RESULT(S)

Chlamydia trachomatis infection poses a major threat to human reproduction. Biological and epidemiological evidence suggests that progression of Chlamydia infection causes intense and persistent inflammation, injury, and scarring in the fallopian tube, leading to a substantially increased risk of ectopic pregnancy and infertility. The main targets of Chlamydia infection are epithelial cells lining the mucosal surface, which play a central role in host immune responses and pathophysiology. Tubal phenotypes at the cellular level in mutant mice appear to reflect alterations in the balance between inflammatory mediator and factor deficiency. While studies in mice infected with Chlamydia muridarum have provided insight into potential inflammatory mediators linked to fallopian tube pathology, it is unclear how inflammation induced by Chlamydia infection prevents or retards normal tubal transport and causes embryo implantation in the fallopian tube.

CONCLUSION(S)

Given the similarities in the tubal physiology of humans and rodents, knockout mouse models can be used to study certain aspects of tubal functions, such as gamete transport and early embryo implantation. Elucidation of the exact molecular mechanisms of immune and inflammatory responses caused by Chlamydia infection in human fallopian tubal cells in vitro and understanding how Chlamydia infection affects tubal transport and implantation in animal studies in vivo may explain how Chlamydia trachomatis infection drives inflammation and develops the tubal pathology in women with tubal ectopic pregnancy.