Endometrial HOXA10 expression after controlled ovarian hyperstimulation with recombinant follicle-stimulating hormone

Uterine Fibroids and Infertility

Infertility is a disease of the reproductive system defined by the failure to achieve a clinical pregnancy after 12 months or more of regular unprotected sexual intercourse. Uterine fibroids are the most common tumor in women, and their prevalence is high in patients with infertility. Fibroids may be the sole cause of infertility in 2–3% of women. Depending on their location in the uterus, fibroids have been implicated in recurrent pregnancy loss as well as infertility. Pregnancy and live birth rates appear to be low in women with submucosal fibroids; their resection has been shown to improve pregnancy rates. In contrast, subserosal fibroids do not affect fertility outcomes and their removal does not confer any benefit. Intramural fibroids appear to reduce fertility, but recommendations concerning their treatment remain unclear. Myomectomy should be discussed individually with the patient; other potential symptoms such as dysmenorrhea or bleeding disorders should be included in the indication for surgery.

Effects of Hydrosalpinx on Endometrial Implantation Failures: Evaluating Salpingectomy in Women Undergoing in vitro fertilization

Hydrosalpinx is a disease characterized by the obstruction of the salpinx, with progressive accumulation in the shape of a fluid-filled sac at the distal part of the tuba uterina, and closed to the ovary. Women with hydrosalpinges have lower implantation and pregnancy rates due to a combination of mechanical and chemical factors thought to disrupt the endometrial environment. Evidence suggests that the presence of hydrosalpinx reduces the rate of pregnancy with assisted reproductive technology. The main aim of the present is review to make an overview of the possible effects of hydrosalpinx on in vitro fertilization (IVF). We conducted a literature search on the PubMed, Ovid MEDLINE, and Google Scholar data bases regarding hydrosalpinx and IVF outcomes. Hydrosalpinx probably has a direct toxic effect on sperm motility and on the embryos. In addition, the increasing liquid inside the salpinges could alter the mechanisms of endometrial receptivity. The window of endometrial receptivity is essential in the implantation of blastocysts, and it triggers multiple reactions arising from the endometrium as well as the blastocysts. Hydrosalpinx could influence the expression of homeobox A10 (HOXA10) gene, which plays an essential role in directing embryonic development and implantation. Salpingectomy restores the endometrial expression of HOXA10; therefore, it may be one mechanism by which tubal removal could result in improved implantation rates in IVF. In addition, salpingectomy does not affect the ovarian response, nor reduces the antral follicle count. Further studies are needed to establish the therapeutic value of fluid aspiration under ultrasonographic guidance, during or after oocyte retrieval, in terms of pregnancy rate and ongoing pregnancy.

Increased Progesterone on the Day of Administration of hCG in Controlled Ovarian Hyperstimulation Affects the Expression of HOXA10 in Primates' Endometrial Receptivity

The increase in progesterone (P4) levels on the day of human chorionic gonadotropin (hCG) administration have a negative effect on endometrial receptivity. There are few reports regarding the expression of homeobox A10 (HOXA10) as one of many biomolecular factors of endometrial receptivity. To evaluate the effect of increased P4 concentration on the day of hCG administration on HOXA10, a total of 16 Macaca nemestrina were divided into three dose groups of recombinant-follicle stimulating hormone (rFSH) (30IU, 50IU, and 70IU) and one control group. Injection of rFSH combined with gonadotropin release hormone (GnRH) at 160 ug/day was given subcutaneously using a long protocol technique. Blood samples for estradiol (E2) and (P4) concentration measurements were taken on the day of injecting hCG in the final follicular phase, while the collection of endometrial tissue for HOXA10 measurement was carried out 8 to 10 days after hCG administration. E2 and P4 were measured by ELISA, whereas HOXA10 expression was measured with immunohistochemical (IHC) techniques. The concentration of E2 and P4 was found to be higher in dose groups compared with the natural group, but no significant differences were found within the group. For the Hscore for HOXA10 expression, no significant differences within dose groups were found. In addition, no significant differences for the Hscore for HOXA10 were found when compared to E2 groups. Significantly, the Hscore of HOXA10 was found to be >1 ng/mL in the P4 group compared with the Hscore HOXA10 in the P4 natural group (p = 0.022). The high concentration of P4 caused by ovarian hyperstimulation in the follicular phase stimulates the expression of HOXA10 in the secretion phase.

Effects of Supraphysiologic Levels of Estradiol on Endometrial Decidualization, sFlt1, and HOXA10 Expression

OBJECTIVE

Supraphysiologic estradiol (E₂) levels associated with controlled ovarian hyperstimulation in high in vitro fertilization (IVF) responders may alter implantation and placentation and increase the risk of preeclampsia. Our hypothesis is that elevated E₂ levels in vitro significantly alter endometrial decidualization, sFlt1, and HOXA10 expression.

METHODS

Human endometrial stromal cells were treated with a decidualization cocktail of medroxyprogesterone, cyclic adenosine monophosphate, and 3 concentrations of E₂ 10 nM (standard), 100 nM (intermediate), or 1000 nM E₂ (high). Effects on sFlt1, prolactin (PRL), insulin-like growth factor binding protein 1 (IGFBP-1), vascular endothelial growth factor (VEGF), and HOXA10 were studied.

RESULTS

Prolactin, IGFBP-1, and VEGF significantly increased at all 3 E₂ concentrations. While IGFBP-1 and VEGF did not change with increasing E₂, PRL was less with high E₂ (6.0 ng/mL ± 1.4 standard error of the mean) compared to standard (21.4 ± 3.2) and intermediate (19.8 ± 3.8). sFlt1 decrease was similar at all E₂ concentrations. HOXA10 was lower at standard (10%) and intermediate (30%) as expected, but did not change with high E₂.

CONCLUSIONS

Supraphysiologic E₂ levels associated with high IVF responders that exceed in vivo levels may impair in vitro endometrial decidualization. Although PRL did increase with high E₂, the levels were, however, attenuated and 3.4-fold lower than standard and intermediate E₂. sFlt1 was decreased under all 3 conditions with no differences between concentrations. Reduced HOXA10 was not observed with high E₂. These findings suggest that elevated E₂ levels in vitro may alter endometrial decidualization and subsequently affect implantation and placentation.

Aberrant Expression of lncRNA ( HOXA11-AS1) and Homeobox A ( HOXA9, HOXA10, HOXA11, and HOXA13) Genes in Infertile Women With Endometriosis

This study aimed to study the expression of homeobox (HOX)A11-AS1 ( HOXA11 antisense RNA) long noncoding RNA (lncRNA) and the expression of homeobox A ( HOXA9, HOXA10, HOXA11, and HOXA13) genes in the eutopic (EU) and ectopic (EC) endometria of women with peritoneal endometriosis. A total of 30 women undergoing laparoscopic surgery for peritoneal endometriosis and 15 infertile women without endometriosis were enrolled in this study. Peritoneal EC tissue samples were obtained through surgery. The EU tissues were obtained by curettage. The EC and EU lncRNA and messenger RNA (mRNA) expression levels were measured using real-time reverse transcriptase-polymerase chain reaction. The HOXA11-AS1 lncRNA and HOXA9, HOXA10, HOXA11, and HOXA13 mRNA were expressed at significantly lower levels in the EU than in the EC, that is, in women with peritoneal endometriosis ( P < .05). The expression levels of HOXA10 and HOXA11 in the EU were significantly lower in women with peritoneal endometriosis compared to the control group participants ( P < .05), whereas the levels of lncRNA ( HOXA11-AS1), HOXA9, and HOXA13 did not differ significantly between the 2 patient groups ( P > .05). In conclusion, the study findings suggest that HOXA11-AS1 lncRNA may play a role in the development of peritoneal endometriosis, but HOXA11-AS1 may not influence endometrial receptivity in endometriosis-associated infertility.

GnRH analogues may increase endometrial Hoxa10 promoter methylation and affect endometrial receptivity

The present study aimed to investigate whether gonadotropin-releasing hormone analogues (GnRH-as), including GnRH agonists and antagonists, affect endometrial homeobox (Hox) a10 DNA methylation during the implantation window in mice. GnRH analogue mouse models were used and were treated with either human menopausal gonadotropin (HMG) and a GnRH agonist or HMG and a GnRH antagonist. Uterus samples were collected 48 h after GnRH analogue treatment or ovulation. Bisulfite sequencing polymerase chain reaction (PCR), quantitative-PCR and western blot analysis were performed to assess Hoxa10 and integrin β3 expression. Scanning electron microscope analyses were conducted to analyze pinopode development. Compared with the natural cycle control mice, mice in the GnRH analogue groups were found to exhibit increased levels of methylation at the Hoxa10 promoter, decreased Hoxa10 mRNA and protein expression and disrupted pinopode development. These findings suggest that GnRH-as may be associated with altered Hoxa10 DNA methylation, thus GnRH-as may affect uterine Hoxa10 expression and endometrial receptivity.

Effect of transcutaneous electrical acupuncture point stimulation on endometrial receptivity in women undergoing frozen-thawed embryo transfer: a single-blind prospective randomised controlled trial

OBJECTIVE

To evaluate the effect of transcutaneous electrical acupuncture point stimulation (TEAS) on endometrial HOXA10 protein expression and three-dimensional (3D) power Doppler ultrasound parameters as markers of endometrial receptivity in women undergoing frozen-thawed embryo transfer (FET).

METHODS

A total of 68 women undergoing FET were randomised to receive TEAS or mock TEAS at acupuncture points CV3, CV4 and SP6 and Zigong bilaterally. Both groups had six sessions per cycle for three menstrual cycles prior to the scheduled FET. Each session lasted 30 min and was repeated every other day. 3D power Doppler ultrasound parameters, HOXA10 protein expression and rates of embryo implantation, clinical pregnancy and live birth were compared.

RESULTS

There were no significant differences between the two groups in endometrial thickness or endometrial volume. The ultrasonographic endometrial triple-line pattern was present more often in the TEAS group (p=0.002). The TEAS group had a greater endometrial and subendometrial vascularisation index (VI) than the mock TEAS group (p=0.001 and p<0.001, respectively) on 3D ultrasound and increased endometrial HOXA10 expression (p=0.001) immediately prior to FET. Subsequently, the rates of embryo implantation, clinical pregnancy and live birth rates were all higher in the TEAS group than in the mock TEAS group (p=0.024, p=0.038 and p=0.033, respectively).

CONCLUSIONS

In patients undergoing FET, TEAS may have beneficial effects on endometrial HOXA10 expression and ultrasound markers of endometrial receptivity. These findings may explain the improvement in clinical outcome of FET associated with the use of TEAS.

TRIAL REGISTRATION NUMBER

ChiCTR-TRC-14004448.

Cessation of gonadotropin-releasing hormone antagonist on triggering day in flexible multiple-dose protocol: A randomized controlled study

Objective

To investigate outcomes of stimulated IVF cycles in which GnRH antagonist was omitted on the ovulation triggering day.

Methods

A total of 86 women who underwent controlled ovarian hyperstimulation with recombinant FSH and GnRH antagonist flexible multiple-dose protocols were recruited and prospectively randomized into the conventional group (group A) or cessation group (group B). The GnRH antagonist, 0.25 mg/day of cetrorelix, was started when the leading follicle reached 14 mm in diameter and was continuously administered until the hCG triggering day (group A, 43 cycles) or until the day before hCG administration (group B, 43 cycles). The maturity of oocytes, fertilization rate, embryo quality, and implantation and clinical pregnancy rates were evaluated.

Results

The duration of ovarian stimulation, total dose of gonadotropins, serum estradiol levels on hCG administration day, and number of oocytes retrieved were not significantly different between the two groups. The total dose of GnRH antagonist was significantly lower in group B than group A (2.5±0.9 vs. 3.2±0.8 ampoules, p<0.05). There was no premature luteinization in any of the subjects. The proportion of mature oocytes and fertilization rate were not significantly different in group B than group A (70.7% vs. 66.7%; 71.1% vs. 66.4%, respectively). There were no significant differences in the implantation or clinical pregnancy rates.

Conclusion

Our prospective randomized study suggested that cessation of GnRH antagonist on the hCG administration day during a flexible multiple-dose protocol could reduce the total dose of GnRH antagonist without compromising its effects on pregnancy rates.

HOXA10 protein expression in the endometrium of normally menstruating women after receiving GnRH antagonist

OBJECTIVE(S)

To compare HOXA10 protein expression in the endometrium between natural control cycles and GnRH antagonist-treated cycles obtained during the window of implantation of normally menstruating women.

STUDY DESIGN

This study was conducted at the Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand. Thirty-five volunteers were recruited into this prospective, self-controlled study, which was divided into two cycles, the first a natural control cycle and the second a GnRH antagonist-treated cycle. The two cycles were separated by one resting cycle. In the GnRH antagonist-treated cycle, when the leading follicle was 15 mm, ganirelix (Orgalutran®) 0.25mg was administered daily. In both cycles, ovulation was induced when the largest follicle reached 18 mm in diameter. Finally, endometrial biopsy was performed on day 6 after documented ovulation, which corresponds to the window of implantation. Endometrial HOXA10 protein expression, a marker of endometrial receptivity, was analyzed by immunohistochemistry. The protein expression was compared between the two cycles regarding their percentage of immunostained cells and IHC-scores (percentage of stained cells×intensity of nuclear staining).

RESULTS

HOXA10 protein was exclusively localized in the stromal compartment of the endometrium. The percentage of HOXA10 nuclear staining in the endometrium collected from GnRH antagonist-treated cycles was higher than that of the natural cycles, whereas the IHC-scores showed no difference between the two cycles.

CONCLUSION(S)

GnRH antagonists may have no effect on HOXA10 protein expression in the endometrium obtained during the implantation window of normally menstruating women.

Tissue selective estrogen complexes (TSECs) differentially modulate markers of proliferation and differentiation in endometrial cells

Selective estrogen receptor modulators (SERMs) have tissue-specific estrogen receptor (ER) modulating properties. Combining an SERM with one or more estrogens to form a tissue selective estrogen complex (TSEC) can provide an improved blend of tissue-specific ER agonist and antagonist effects. While both estrogens and SERMs affect the uterine endometrium, not all TSECs reverse the endometrial effects of estrogens preventing endometrial proliferation and hyperplasia. Their action in uterine cells is not completely understood. HOXA 10, leukemia inhibitory factor (LIF), progesterone receptor (PR), and EMX2 are genes known to regulate endometrial proliferation and differentiation. The expression of these genes was used to assess endometrial effects of SERMs and TSECs. We evaluated the effects of raloxifene (RAL), tamoxifen (TAM), lasofoxifene (LAS), bazedoxifene acetate (BZA), and progesterone (P) alone and in combination with estradiol (E2) in Ishikawa cells. Increased HOXA10, LIF, PR, and EMX2 messenger RNA (mRNA) expression was noted in E2-treated cells compared with vehicle-treated controls. All TSECs maintained E2-induced PR expression and all except TAM prevented estrogen-induced LIF expression. The TSEC containing BZA uniquely decreased HOXA10 expression and increased EMX2 expression. The TSECs alter endometrial cell proliferation by selective modulation of estrogen responsive genes, maintaining the antiproliferative effects mediated by PR and inhibiting LIF. The differential effect of TSECs on endometrial gene expression suggests a mechanism by which they manifest differential effects on endometrial safety against the risk of estrogen-induced endometrial hyperplasia.

HOXA10 expression is decreased in endometrium of women with adenomyosis

HOXA10 gene expression is decreased in the secretory phase endometrium of women with adenomyosis. Diminished expression of HOXA10 is a potential mechanism explaining decreased implantation observed in women with adenomyosis.

Endometrial polyps affect uterine receptivity

This case-control study evaluated the effect of hysteroscopically identified endometrial polyps on endometrium by means of HOXA10 and HOXA11, known molecular markers of endometrial receptivity. Uteri with endometrial polyps demonstrated a marked decrease in HOXA10 and HOXA11 messenger RNA levels, which may impair implantation. These findings suggest a molecular mechanism to support the clinical findings of diminished pregnancy rates in women with endometrial polyps.

The expression of cyclooxygenase-2 in cervical cancers and Hela cells was regulated by estrogen/progestogen

To investigate the relationship between the expression of cyclooxygenase-2 (COX-2) and menstrual cycle, the regulatory effects of 17-beta-estradiol (E(2)) and medroxyprogesterone acetate (MPA) on the expression of COX-2 in cervical cancer Hela cells were examined. Cervical cancer specimens were obtained from 47 pre-menopausal patients. The phase of menstrual cycle was determined by case history and HE staining of uterine endometrium. COX-2 was immunohistochemically stained by SABC staining and the staining intensity was determined with computerized image analysis system. Hela cells were incubated with alcohol, E(2), E(2)+MPA, MPA for 12, 24 and 48 h respectively. The expression of COX-2 in Hela cells was detected by Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR). Our results showed that the expression of COX-2 was significantly higher during proliferative phase than secretory phase (P<0.05), but there was no difference in the positive rate between proliferative phase and secretory phase (P>0.05). Incubation with E(2) could significantly enhance the expression of COX-2 continually. On the contrary, E(2)+MPA and MPA alone could decrease the expression of COX-2 as compared with the control and E(2) group (P<0.05 and P<0.01 respectively). It is concluded that the expression of COX-2 in cervical cancer of pre-menopausal patients and Hela cells was regulated by estrogen/progestogen.

Regulatory effect of estrogen, progestin and HB-EGF on the expression of HOXA10 gene in Ishikawa cells

HOXA10 gene plays an essential role in differentiation of the endometrium and in human reproduction. The aim of this study was to investigate the regulatory effect of sex steroids and HB-EGF on HOXA10 gene in Ishikawa cells. Ishikawa cells were incubated with 17-beta estradiol (10(-8) mol/L), medroxyprogesterone acetate (MPA) (10(-6) mol/L), RU486 (10(-5) mol/L) or HB-EGF (10 ng/mL) for 48 h respectively. The expression of HOXA10 gene was detected by immunofluorescence, reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. Our results showed that either estrogen alone, progestin alone or progestin combined with estrogen could significantly increase the expression of HOXA10 gene 48 h after the treatment (P<0.05). But estrogen combined with progestin and RU486 could inhibit the up-regulation by estrogen and progestin. HB-EGF could elevate the expression of HOXA10 gene 48 h after the treatment (P<0.05). It is concluded that both estrogen and progestin can up-regulate the expression of HOXA10 gene in Ishikawa cells, but RU486 can inhibit the effect and HB-EGF can elevate the expression level of HOXA10 gene.

HOXA10 inhibits Kruppel-like factor 9 expression in the human endometrial epithelium

Kruppel-like factor 9 (KLF9) is a zinc finger transcription factor that regulates estrogen and progesterone action by modulating the activity of progesterone receptor (PGR). The transition from proliferative to secretory endometrial epithelium involves loss of estrogen receptor/PGR expression and loss of direct response to sex steroids. HOXA10 partially mediates progesterone responsiveness in the endometrium. Here, we demonstrate that HOXA10 directly regulates KLF9 in endometrial epithelial cells and not in stromal cells. Immunohistochemistry performed on endometrial tissue obtained from normal, reproductive-age women revealed that KLF9 expression was decreased in the secretory phase of the menstrual cycle compared to the proliferative phase. In vitro, HOXA10 transfection of human endometrial epithelial cells (Ishikawa), but not stromal cells (HESC), resulted in a greater than 50% decrease in KLF9 mRNA and protein expression. Reporter constructs driven by the KLF9 promoter were repressed by cotransfection with HOXA10. Electrophoretic mobility shift assay was used to demonstrate direct binding of HOXA10 to the KLF9 promoter. Targeted mutation of the HOXA10-binding site in the KLF9 promoter resulted in loss of HOXA10 binding and loss of repression by HOXA10 in reporter assays. HOXA10 directly and selectively repressed KLF9 expression in endometrial epithelial cells. HOXA10 repression of KLF9 likely contributes to the loss of sex steroid responsiveness in secretory-phase endometrial epithelium.

Submucosal uterine leiomyomas have a global effect on molecular determinants of endometrial receptivity

OBJECTIVE

To evaluate the effect of uterine leiomyomas on the endometrium using molecular markers of endometrial receptivity: HOXA10, HOXA11, LIF, and BTEB1.

DESIGN

Case-control study.

SETTING

University medical center.

PATIENT(S)

Thirty reproductive-aged women with submucosal, intramural, or no uterine myomas who underwent hysteroscopy or hysterectomy.

INTERVENTION(S)

Proliferative phase endometrial sampling was performed at the time of surgery. In uteri with a submucosal myoma, directed endometrial biopsies were obtained over the myoma and over normal myometrium.

MAIN OUTCOME MEASURE(S)

Endometrial HOXA10 expression was evaluated as a primary endpoint using quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry. HOXA11, BTEB1, and LIF were evaluated using real-time RT-PCR.

RESULT(S)

Endometrial HOXA10 and HOXA11 messenger RNA (mRNA) expression were significantly decreased in uteri with submucosal myomas compared with controls and with uteri with intramural myomas. A similar trend was seen in BTEB1 mRNA expression; however, no difference was found in LIF mRNA expression. Immunohistochemistry localized the decrease in endometrial HOXA10 protein expression to stroma. In the presence of a submucosal myoma, there were no regional differences in gene expression.

CONCLUSION(S)

The molecular mechanism by which submucosal myomas adversely affect reproduction includes a global decrease in endometrial HOX gene expression, not simply a focal change over the myoma. This may explain the reproductive dysfunction observed with submucosal myomas.

GnRH antagonists may affect endometrial receptivity

OBJECTIVE

HOXA10 is an essential regulator of endometrial receptivity. To determine the effect of GnRH antagonists on endometrial receptivity, we assessed endometrial HOXA10 expression in GnRH antagonist, GnRH agonist, and natural cycles.

DESIGN

Prospective case-control study.

SETTING

University academic medical center.

PATIENT(S)

Nineteen subjects were included: 12 subjects underwent controlled ovarian hyperstimulation with recombinant FSH and used either a GnRH antagonist or a GnRH agonist; seven control subjects underwent natural cycles.

INTERVENTION(S)

Pipelle endometrial biopsies were obtained 11 days after hCG administration or spontaneous LH surge in untreated cycles, respectively. Immunohistochemistry was used to assess HOXA10 protein expression in endometrial glands and stroma.

MAIN OUTCOME MEASURE(S)

Endometrial HOXA10 protein expression.

RESULT(S)

HOXA10 expression was significantly decreased in endometrial stromal cells in GnRH antagonist-treated cycles compared with GnRH agonist-treated cycles or natural cycle control subjects. There was no significant difference in glandular cell HOXA10 expression among the three groups.

CONCLUSION(S)

Use of GnRH antagonists may be associated with impaired HOXA10 expression in endometrial stromal cells and thus may affect endometrial receptivity.

A processed metabolite of luteinizing hormone-releasing hormone has proliferative effects in endometrial cells

OBJECTIVE

The purpose of this study is to determine the possible role of the processed peptide of LHRH, LHRH-(1-5), in regulating growth of endometrial cancer cells.

STUDY DESIGN

An endometrial cancer cell line, the Ishikawa cell line, was cultured under standard conditions and treated in a dose-dependent manner with 1 of 2 hormones, LHRH and LHRH-(1-5) to determine the ability of these peptides to regulate cellular growth. A tetrazolium-based assay was used to determine the effect these peptides have on cell proliferation. Furthermore, enzyme-linked immunosorbent assay (ELISA)-based assays were used to determine the expression of caspase-3/7 and pERK-1/2. Statistical analyses were conducted using an analysis of variance followed by Fisher LSD as the post-hoc test.

RESULTS

The results show that LHRH is anti-proliferative whereas LHRH-(1-5) is proliferative on the cells. Furthermore, LHRH-(1-5) decreased caspase-3/7 and pERK1/2 expression.

CONCLUSION

This is the first time LHRH-(1-5) is shown to have proliferative effects on cells.

The human endometrium as a fertility-determining factor

Intensive research work has been performed to better understand the regulation of the endometrium and its clinical implications to improve implantation. Although many proteins and molecules may influence endometrial development, their co-ordinated contribution to the implantation process is still poorly understood and a translation into clinical use has not sufficiently been performed. Clinical evaluation of the endometrium by ultrasound and other techniques, like endometrial biopsy and analysis of uterine secretions, has been intensively studied and therapeutic options to improve endometrial function have been suggested and tested. Systemic treatment with heparin, aspirin or corticosteroids did not result in improved implantation rates. Gene therapy and cervical treatment, e.g. with seminal plasma, are still in the phase of clinical research. Therefore, this review focuses on different aspects of endometrial research, which all contribute to the diagnosis, evaluation and therapy of endometrial function and dysfunction. First, the endometrial development towards a receptive milieu is described. Second, the actual clinical evaluation of endometrial receptivity, possible therapeutic strategies and in particular, the evaluation of endometrial function in the non-natural situation of hormonal stimulation is critically evaluated. In conclusion, the endometrium shall be considered as an important fertility-determining factor and therapeutic options should be developed in near future.

Endocrine regulation of HOX genes

Hox genes have a well-characterized role in embryonic development, where they determine identity along the anteroposterior body axis. Hox genes are expressed not only during embryogenesis but also in the adult, where they are necessary for functional differentiation. Despite the known function of these genes as transcription factors, few regulatory mechanisms that drive Hox expression are known. Recently, several hormones and their cognate receptors have been shown to regulate Hox gene expression and thereby mediate development in the embryo as well as functional differentiation in the adult organism. Estradiol, progesterone, testosterone, retinoic acid, and vitamin D have been shown to regulate Hox gene expression. In the embryo, the endocrine system directs axial Hox gene expression; aberrant Hox gene expression due to exposure to endocrine disruptors contributes to the teratogenicity of these compounds. In the adult, endocrine regulation of Hox genes is necessary to enable such diverse functions as hematopoiesis and reproduction; endocrinopathies can result in dysregulated HOX gene expression affecting physiology. By regulating HOX genes, hormonal signals utilize a conserved mechanism that allows generation of structural and functional diversity in both developing and adult tissues. This review discusses endocrine Hox regulation and its impact on physiology and human pathology.

Extrapituitary effects of GnRH antagonists in assisted reproduction: a review

GnRH antagonists are used to prevent premature LH surges in assisted reproduction. The pregnancy rates obtained in several studies have been similar to those obtained in the long protocol with gonadotrophin-releasing hormone (GnRH) agonists. However, lower oestrogen serum concentrations have been observed and fewer oocytes retrieved using GnRH antagonists. Thus, potential effects at extrapituitary GnRH receptors in the ovary and the endometrium have been claimed. The article reviews the currently available data from the literature as well as current investigations with respect to effects of cetrorelix on the ovary and the endometrium. No evidence was found to support the hypothesis of extrapituitary effects of GnRH antagonists such as cetrorelix at doses used in assisted reproduction.