Correlation of pinopod development on uterine luminal epithelial surface with hormonal events and endometrial sensitivity in rat

Ultrasound Molecular Imaging of Neovascularization for Evaluation of Endometrial Receptivity Using Magnetic iRGD-Modified Lipid-Polymer Hybrid Microbubbles

BACKGROUND

Angiogenesis plays an important role in endometrial receptivity, determining the response of the endometrium to the blastocyst at the early stage of embryo implantation. During the application of assisted reproduction technologies, it is very important to evaluate the status of uterine angiogenesis before deciding on embryo implantation. Targeted microbubbles (MBs)-based ultrasound molecular imaging (UMI) can noninvasively detect the expression status of biomarkers at the molecular level, thereby being a potential diagnosis strategy for various diseases and their therapeutic evaluation.

METHODS

The iRGD-lipopeptide (DSPE-PEG2000-iRGD) conjugate was prepared with iRGD peptides and DSPE-PEG2000-maleimide through the Michael-type addition reaction. Then, the magnetic iRGD-modified lipid-polymer hybrid MBs (Mag-iLPMs) were prepared with the double-emulsification-solvent-evaporation method. Magnetic targeting of Mag-iLPMs was confirmed under the microscope, followed by a rectangular magnet. Next, the in vitro targeted binding of MBs to murine brain-derived endothelial cells.3 (bEnd.3) and human umbilical vein endothelial cells (HUVEC) were evaluated. The ratio of MBs binding to bEnd.3 and HUVEC at the same field was also compared. For in vivo studies, bolus injections of targeted or control MBs were randomly administrated to non-pregnant or pregnant rats on day 5. Then, the uteri were imaged using a VisualSonics Vevo 2100 ultrasound system (Fujifilm VisualSonics Inc., Ontario, Canada) equipped with a high-frequency transducer. Ultrasonic imaging signals were acquired from Mag-iLPMs, and compared with Mag-LPMs, iLPMs, and LPMs.

RESULTS

The Mag-iLPMs showed excellent performance in ultrasound contrast imaging and binding affinity to target cells. Using the magnetic field, 10.5- and 12.47-fold higher binding efficiency to bEnd.3 and HUVEC were achieved compared to non-magnetic iLPMs, respectively. Significantly enhanced UMI signals were also observed in the uteri of rats intravenously injected pregnant rats (6.58-fold higher than rats injected with iLPMs).

CONCLUSION

We provided a powerful ultrasonic molecular functional imaging tool for uterine angiogenesis evaluation before embryonic implantation.

Electroacupuncture Improves Pregnancy Outcomes in Rats with Thin Endometrium by Promoting the Expression of Pinopode-Related Molecules

A thin endometrium affects the success of assisted reproduction due to low endometrial receptivity. Acupuncture improves endometrial receptivity and promotes the formation of pinopodes, the ultrastructure marker implantation window. However, the specific underlying mechanisms remain unclear. In this study, the efficacy of acupuncture treatment and its underlying mechanism were investigated by analyzing pregnancy rate, pinopode formation, and related molecular markers in thin endometrium model rats. Absolute ethanol (95%) was injected into the uteruses of female Sprague-Dawley rats to construct a thin endometrium model. In this model, acupuncture stimulation at EX-CA1, SP6, and CV4 ameliorated the pregnancy rate. Significantly increased embryo implantation, endometrial thickness, numbers of glands, and blood vessels were observed in the electroacupuncture (EA) group compared to the model group. The number of pinopodes in the EA group was abundant, with a shape similar to that of the control group. Additionally, significantly higher expression levels of pinopode-related markers, including integrin αvβ3, homeobox A10 (HOXA10), heparin-binding EGF-like growth factor (HBEGF), estrogen receptor alpha (ERα), and progesterone receptor (PR), were observed in the EA group than those in the model group. In conclusion, EA had a positive effect on the endometrial receptivity of thin endometrium model rats by improving pinopode formation through multiple molecular targets.

Testosterone Decreases the Number of Implanting Embryos, Expression of Pinopode and L-selectin Ligand (MECA-79) in the Endometrium of Early Pregnant Rats

Testosterone could have adverse effect on fertility. In this study, we hypothesized that this hormone could reduce the number of embryo implantations via affecting the normal endometrium ultrastructure and expression of endometrial proteins involved in implantation. Therefore, the aims were to identify these adverse testosterone effects. Methods: Intact pregnant rats were given 250 or 500 µg/kg/day testosterone for three days, beginning from day 1 of pregnancy. Rats were euthanized either at day 4 to analyze the ultra-structural changes in the endometrium and expression and distribution of MECA-79 protein, or at day 6 to determine the number of implantation sites. Results: Administration of 500 µg/kg/day testosterone suppresses endometrial pinopodes development and down-regulates expression and distribution of MECA-79 protein in the uterus. In addition, the number of implantation sites were markedly decreased. Conclusions: Changes in endometrial ultrastructure and expression of implantation protein in the endometrium in early pregnancy period could be the reason for failure of embryo implantation under testosterone influence.

Hashimoto's thyroiditis impairs embryo implantation by compromising endometrial morphology and receptivity markers in euthyroid mice

BACKGROUND

Although thyroid dysfunction caused by Hashimoto's thyroiditis (HT) is believed to be related to implantation failure due to the underdevelopment of the receptive uterus, it is unknown whether HT itself, even in the euthyroid state, impairs embryo implantation associated with endometrial receptivity defects. To address whether HT itself can affect endometrial receptivity accompanied by implantation alterations, a euthyroid HT model was established in mice.

METHODS

Female NOD mice were immunized twice with thyroglobulin and adjuvant to induce the experimental HT model. Four weeks after the second treatment, the mice were normally mated, and pregnant ones were sacrificed in implantation window for thyroid-related parameter and steroid hormones measurements by electrochemiluminescence immunoassay and enzyme-linked immunosorbent assay and implantation site number calculation by uptake of Chicago Blue dye. In addition, certain morphological features of endometrial receptivity were observed by hematoxylin-eosin staining and scanning electron microscopy, and the expression of other receptivity markers were analyzed by immunohistochemistry, RT-qPCR or Western Blot.

RESULTS

HT mice displayed intrathyroidal monocyte infiltration and elevated serum thyroid autoantibody levels without thyroid dysfunction, defined as euthyroid HT in humans. Euthyroid HT resulted in implantation failure, fewer pinopodes, retarded pinopode maturation, and inhibited expression of receptivity markers: estrogen receptor α (ERα), integrin β3, leukemia inhibitory factor (LIF), and cell adhesion molecule-1 (ICAM-1). Interestingly, despite this compromised endometrial receptivity response, no statistical differences in serum estradiol or progesterone level between groups were found.

CONCLUSIONS

These findings are the first to indicate that HT induces a nonreceptive endometrial milieu in the euthyroid state, which may underlie the detrimental effects of HT itself on embryo implantation.

Therapeutic Effects of VEGF Gene-Transfected BMSCs Transplantation on Thin Endometrium in the Rat Model

Objective

Bone mesenchymal stem cells (BMSCs) transplantation has a therapeutic effect on the thin endometrium in animal researches and clinical trials. The present study aims at assessing whether transplantation of VEGF-transfected BMSCs (VEGF-BMSCs) have a better therapeutic effect on endometrial regeneration and endometrial receptivity compared with BMSCs therapy alone.

Methods

Sprague-Dawley (SD) rats were used in the study. Thin endometrium model was established with 95% ethanol injection into uterine. VEGF-BMSCs or BMSCs was transplanted via tail vein IV injection. Endometrial thickness, morphology, and pinopodes were assessed by hematoxylin and eosin (HE) staining and scanning electron microscope (SEM). The proteins and mRNAs expressions of markers for endometrial cells and endometrial receptivity were measured after treatment. The fertility testing was done to assess the embryo implantation efficiency.

Results

VEGF-BMSCs transplantation significantly increased endometrial thickness compared with the BMSCs group and the control group. There was no significant difference in endometrial thickness between VEGF-BMSCs group and sham operation group. Importantly, in protein level, expressions of cytokeratin, vitamin, VEGF, LIF, and integrin α_νβ ₃ in VEGF-BMSC group were increased dramatically compared with those of the control group and BMSC group both 4 days and 8 days after stem cells transplantation. Accordingly, mRNA expression of LIF and integrin α _ν β ₃ was significantly upregulated compared with those of the control group and BMSC group both 4 and 8 days after treatment. The pinopodes were developed better in the VEGF-BMSCs group and the sham operation group compared with BMSCs group and the control group. The number of embryo implantation is largest in the sham operation group, followed by VEGF-BMSCs group, BMSCs group, and the control group.

Conclusions

Transplantation of VEGF gene-transfected BMSCs may be a better therapeutic treatment for thin endometrium than stem cell therapy alone.

Sophoricoside fails the embryo implantation by compromising the uterine endometrial receptivity at implantation "window" of pregnant mice

Sophoricoside (SOPH) is an isoflavone glycoside isolated from the fruits of Sophora japonica. Since its first isolation in 1961, there are rare findings about the effects of SOPH on reproductive system. In the present study, the pregnant mice administrated by different doses of SOPH were used to explore the effect of SOPH on embryo implantation, especially on the endometrial receptivity. The statistical results showed that the number of implanted embryos was gradually declining along the increasing dose of SOPH. When the administrated dose of SOPH was 600 mg/kg per day, great changes were observed in the exposed uterine morphology and up-regulated progesterone receptor (PR) and down-regulated estrogen receptor α (ERα), E-cadherin, matrix metalloproteinase-2 (MMP-2) and integrin β3 were also found in SOPH-exposed uterine. These findings demonstrated that SOPH exposure reduced the number of implanted embryos in a dose-dependent manner and failed the embryo implantation through altering the morphology of uterine and compromising the endometrial receptivity.

Anti-cancer potential of a novel SERM ormeloxifene

Ormeloxifene is a non-steroidal Selective Estrogen Receptor Modulator (SERM) that is used as an oral contraceptive. Recent studies have shown its potent anti-cancer activities in breast, head and neck, and chronic myeloid leukemia cells. Several in vivo and clinical studies have reported that ormeloxifene possesses an excellent therapeutic index and has been well-tolerated, without any haematological, biochemical or histopathological toxicity, even with chronic administration. A reasonably long period of time and an enormous financial commitment are required to develop a lead compound into a clinically approved anti-cancer drug. For these reasons and to circumvent these obstacles, ormeloxifene is a promising candidate on a fast track for the development or repurposing established drugs as anti-cancer agents for cancer treatment. The current review summarizes recent findings on ormeloxifene as an anti-cancer agent and future prospects of this clinically safe pharmacophore.

Molecular mechanisms of treatment resistance in endometriosis: the role of progesterone-hox gene interactions

HOX genes, encoding homeodomain transcription factors, are dynamically expressed in endometrium, where they are necessary for endometrial growth, differentiation, and implantation. In human endometrium, the expression of HOXA10 and HOXA11 is driven by sex steroids, with peak expression occurring at time of implantation in response to rising progesterone levels. However, the maximal HOXA10 and HOXA11 expression fails to occur in women with endometriosis. In endometriosis, altered progesterone receptor expression or diminished activity may lead to attenuated or dysregulated progesterone response and decreased expression of progesterone-responsive genes including HOX genes in the eutopic endometrium. In turn, other mediators of endometrial receptivity that are regulated by HOX genes, such as pinopodes, alphavbeta3 integrin, and IGFBP-1, are downregulated in endometriosis. HOXA10 hypermethylation has recently been demonstrated to silence HOXA10 gene expression and account for decreased HOXA10 in the endometrium of women with endometriosis. Silencing of progesterone target genes by methylation is an epigenetic mechanism that mediates progesterone resistance. The relatively permanent nature of methylation may explain the widespread failure of treatments for endometriosis-related infertility.

Clinical pharmacokinetics and interaction of centchroman--a mini review

This article provides a brief review of the information available regarding the published pharmacokinetics data for the nonsteroidal, once-a-week oral contraceptive, centchroman (INN: ormeloxifene). This agent is a unique need-oriented contraceptive agent which is included in the National Family Welfare Programme of India. Since 1991, centchroman has been used as a need-oriented contraceptive and is being given for treating dysfunctional bleeding of the uterus. Information regarding absorption, tissue distribution, elimination and kinetic interactions is discussed.

Postcoital interceptive activity of Wrightia tinctoria in Sprague-Dawley rats: a preliminary study

BACKGROUND

This study was aimed to investigate the pregnancy-interceptive activity of the stem bark of Wrightia tinctoria R.Br. (Family Apocynaceae) administered during the preimplantation, peri-implantation and early postimplantation periods by oral route in adult female Sprague-Dawley rats.

STUDY DESIGN

The ethanolic extract of the stem bark and its serial fractions were administered to female rats on Days 1-7 or 1-5 postcoitum (Day 1: day of sperm-positive vaginal smear) by the oral route. At autopsy on Day 10 postcoitum, the number and status of corpora lutea and implantations were recorded. For estrogen-agonistic activity, immature rats ovariectomized 7 days earlier received the test extract or the vehicle once daily for 3 days and, at autopsy on Day 4, uterine weight, status of vaginal opening and extent of vaginal cornification were recorded.

RESULTS

The ethanolic extract of the stem bark of W. tinctoria R.Br. inhibited pregnancy in 100% of rats when administered orally at a 250-mg/kg dose on Days 1-7 or 1-5 postcoitum. On fractionation, the hexane-soluble, chloroform-soluble, water-soluble and water-insoluble fractions showed 100% anti-implantation effect, while n-butanol-soluble fraction intercepted pregnancy in 75% of animals when administered in the Days 1-5 postcoitum schedule. In immature rat bioassay, the active ethanolic extract and its fractions exhibited moderate to potent estrogen-agonistic activity, which might be responsible for their contraceptive action in this species.

CONCLUSIONS

Findings demonstrate the antifertility activity of the ethanolic extract of the stem bark of W. tinctoria and its hexane-soluble, chloroform-soluble, water-soluble and water-insoluble fractions. Studies that pursue promising natural products (to identify contraceptive agents from natural sources lacking potent estrogenic activity) towards a fruitful conclusion for development/lead generation should continue.

Expression of progesterone and oestrogen receptors by early intrauterine equine conceptuses

Progesterone and oestrogen play essential roles in the maintenance of pregnancy in eutherian mammals and are thought to exert their effects on the developing conceptus indirectly, via the endometrium. In some species, early embryos have themselves been shown to express steroid receptors, thereby suggesting that reproductive steroids may also influence embryonic development directly. The aim of this study was to determine whether early intrauterine equine conceptuses express either the classical intracellular progesterone (PR) and oestrogen receptors (ERalpha and ERbeta) or the more recently characterised membrane-bound progesterone receptors (PGRMC1 and mPR). Horse conceptuses recovered on days 7, 10 and 14 after ovulation (n=8 at each stage) were examined for steroid receptor mRNA expression using quantitative rtPCR. Where commercial antibodies were available (PR, ERbeta), receptor localisation was examined immunohistochemically in day 10, 12, 14, 15 and 16 conceptuses (n=2 at each stage). mRNA for PR, PGRMC1 and mPR was detected at all stages examined, but while PGRMC1 and mPR expression increased during the day 7-14 period, PR expression decreased. ERalpha mRNA was not detected at any stage examined, whereas ERbeta mRNA was detected in all day 14, some day 10 and no day 7 conceptuses. Immunoreactive ERbeta receptors were localised to the trophectoderm of day 14-16 conceptuses; PR were not detected immunohistochemically in conceptus tissue. In summary, this study demonstrates that equine conceptuses express mRNA and, in the case of ERbeta, protein for steroid hormone receptors during the period encompassing rapid conceptus growth, differentiation and maternal pregnancy recognition.

Pinopodes are present in Lif null and Hoxa10 null mice

OBJECTIVE

To assess pinopode formation in Lif null and Hoxa10 null mice with infertility secondary to failed implantation.

DESIGN

Controlled animal experiment.

SETTING

Animal research and laboratory facility.

ANIMAL(S)

Lif null, Hoxa10 null, and ICR mice and Sprague-Dawley rats.

INTERVENTION(S)

Endometrial tissue was collected during the peri-implantation period and after ovariectomy.

MAIN OUTCOME MEASURE(S)

Endometrial epithelial tissue was examined under scanning-electron microscopy and assigned a score depending on the number of pinopodes present.

RESULT(S)

Pinopode scores in ICR, Lif null, and Hoxa10 null mice were comparable throughout the peri-implantation period, rising on day 3.5 of pregnancy and remaining elevated through to day 7.5, suggesting that pinopodes are not a good indicator of receptivity in mice. In contrast, pinopode scores in rats clearly demarcated the window of receptivity, appearing on day 4 of pregnancy and declining sharply on day 6. Pinopode scores were low in E(2)-treated ovariectomized mice, but unexpectedly, pinopode scores in vehicle-injected ovariectomized ICR mice were markedly elevated.

CONCLUSION(S)

Lif null and Hoxa10 null mice, in which implantation is impaired, have a similar number of pinopodes to fertile ICR mice. Pinopodes do not define a window of implantation in mice.

Effect of concurrently coadministered drugs on the pharmacokinetic/pharmacodynamic profile of centchroman, a nonsteroidal oral contraceptive, in rats

INTRODUCTION

Centchroman (international nonproprietary name: ormeloxifene) is a nonsteroidal selective estrogen receptor modulator, oral contraceptive, anticancer and antiosteoporotic agent that is intended for long-term use by women. In view of the vast clinical applications and interactions of steroidal oral contraceptives with commonly used therapeutic agents, the interaction potential of certain concomitantly administered therapeutic agents was investigated in terms of postcoital contraceptive efficacy (pharmacological) and the pharmacokinetic profile of centchroman in female Sprague-Dawley rats. The coadministered drugs used in the study were ciprofloxacin, cefixime, amoxicillin, metronidazole, amlodipine, atenolol, theophylline, metformin, pioglitazone and glibenclamide.

MATERIALS AND METHODS

The pharmacological activity of centchroman was evaluated in sperm-positive female rats at 1.5 mg/kg, with or without coadministered drugs. Rats were sacrificed on Day 10 postcoitus, and autopsy was performed to check for the presence or absence of implantations. The estrogenic and antiestrogenic activities of centchroman were evaluated in immature ovariectomized rats. Pharmacokinetic interaction was studied in normal female rats with or without coadministered drugs. Serum samples were taken over 120 h and analyzed using a validated high-performance liquid chromatography method to generate the pharmacokinetic profile of centchroman. Pharmacokinetic parameters were estimated using noncompartmental analysis, and the results were compared.

RESULTS

In pharmacological interaction studies, centchroman alone showed a 100% success rate when given alone or in the presence of coadministered drugs. The only exception was amoxicillin coadministration, with 66% rats in the group showing resorbed implantations. Further investigation with amoxicillin in ovariectomized immature rats indicates no alteration in the estrogenic and antiestrogenic profiles of centchroman. In pharmacokinetic interaction studies, most of the therapeutic agents affected the rate and extent of absorption of centchroman. In other pharmacokinetic parameters, clearance (CL) remained unchanged; however, there was decrease in bioavailability (F) and volume of distribution (V(d)) in some situations.

CONCLUSIONS

The results indicate that there is no direct link between the altered pharmacokinetics of centchroman and the failure of pharmacological effect. The pharmacological interaction with amoxicillin could not be explained on the basis of alteration in the estrogenic and antiestrogenic activities of centchroman, indicating that different mechanisms are involved. The findings, however, suggest that amoxicillin coadministration may result in pharmacological interaction with centchroman and that caution should be taken in clinical practice.

Metoclopramide-induced hyperprolactinaemia caused marked decline in pinopodes and pregnancy rates in mice

BACKGROUND

The impact of hyperprolactinaemia on endometrial function, along with embryo implantation, has been the subject of discussion. This article examines whether experimental hyperprolactinaemia can affect mouse ovarian function, endometrial pinopodes and embryo implantation.

METHODS

For pinopode analysis, 60 female mice were randomly divided into two groups: control (vehicle) and experimental [metoclopramide (MCP) 200 microg per day]. Injections were given subcutaneously for 50 days, and then, normally cycling females were housed with male mice for copulation during proestrus. The animals were killed on the fifth day following coitus when the antimesometrium portions of the uterine horns were removed for endometrial analysis. Blood was collected for prolactin (PRL) determination. In the second experiment, 60 female mice were used to evaluate the ovarian function by measuring estrogen and progesterone levels and counting luteal bodies and oocytes in the oviduct and uterus during estrus.

RESULTS

The highest pregnancy rates and the largest population of pinopodes were both found in the vehicle group (P<0.01). Estrogen and progesterone levels in MCP-treated mice were lower than those in control mice (P<0.05). Also, the number of implantations was significantly lower in the MCP-treated group compared with the vehicle group after embryo transfer (P<0.001).

CONCLUSION

PRL seems to have suppressive effects on ovarian function and the number of pinopodes; conceivably, hyperprolactinaemia has a negative effect on mouse embryo implantation.

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.

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.

Different pattern of pinopodes expression in stimulated mouse endometrium

Adult NMRI mice were superovulated using human menopausal chorionic gonadotropic hormones (hMG and hCG), and then some of them were daily injected with progesterone (1 mg/mouse). At 3.5 and 4.5 days after hCG injection scanning electron micrographs revealed that the hyperstimulated and progesterone-injected group had well-developed pinopodes while most of the hyperstimulated group without progesterone injection had no pinopodes 3.5 days after stimulation. The results suggest that the lifespan of pinopodes is short and changeable during hyperstimulation and that progesterone causes premature formation of the pinopodes and that implantation after ovarian stimulation might depend upon the timing of the pinopode expression.

HoxA10-like proteins in the reproductive tract of the viviparous lizard Eulamprus tympanum and the oviparous lizard Lampropholis guichenoti

The gene HoxA10 and its protein product are essential for the formation of the extensions of the plasma membrane called uterodomes or pinopods in mammalian uterine epithelia. In mice, the presence of the HoxA10 protein and uterodomes is needed for uterine receptivity to blastocyst implantation. The viviparous lizard Eulamprus tympanum displays uterodomes whereas the oviparous lizard Lampropholis guichenoti does not. To explore the theory that HoxA10 is involved in the formation of uterodomes we investigated whether HoxA10 immunoreactive proteins were present in both species during their reproductive cycles. Oviduct proteins from vitellogenic, gravid or non-reproductive L. guichenoti (n=19) and E. tympanum (n=28) were separated by electrophoresis and analysed by Western blot and specific antibodies to HoxA10. E. tympanum displayed HoxA10 immunoreactive bands at 59 and 63 kDa in 20 out of the 28 samples. All of the L. guichenoti samples displayed HoxA10 immunoreactive bands, 18 had bands at 59 and 64 kDa and 1 animal had a single band at 59 kDa. There were no significant differences in the level of HoxA10 immunoreactivity between the different stages of reproductive cycle in either species. The different molecular mass of the larger band in L. guichenoti (64 kDa) compared to E. tympanum (63 kDa) indicates that the two lizards express different isoforms of the HoxA10-like proteins and it will be interesting in future studies to determine whether there are differences in the biological activity of the proteins that regulate different physiological functions in the uterus of viviparous and oviparous lizards.

The antiprogesterone Org 31710 inhibits human blastocyst-endometrial interactions in vitro

OBJECTIVE

To investigate the effect of the anti-P Org 31710 on human blastocyst attachment to cultured endometrial epithelial cells.

DESIGN

Experimental in vitro study.

SETTING

University hospital.

PATIENT(S)

Eleven fertile endometrial donors.

INTERVENTION(S)

Timed endometrial biopsy for cell cultures.

MAIN OUTCOME MEASURE(S)

Blastocyst attachment rate on endometrial cell cultures; secretion of glycodelin and leukemia inhibitory factor into the culture medium measured by RIA and ELISA techniques; and expression of progesterone receptors, interleukin-1 receptor type-1, and integrin subunit beta(3) on endometrial epithelial cells examined by immunohistochemistry. Endometrial pinopodes visualized by scanning electron microscopy.

RESULT(S)

Eleven of 16 human blastocysts attached to control cultures, whereas none of 10 blastocysts attached when Org 31710 was added to the culture medium (P=.0007). Immunohistochemical studies demonstrated no significant differences between groups. Biochemical analyses displayed a trend toward higher glycodelin secretions and, by scanning electron microscopy, a tendency toward less pinopode formation in the Org 31710 group, but the results did not reach statistical significance. The presence of swollen microvilli, precursors of endometrial pinopodes, was significantly reduced on cultures with Org 31710 (P=.03).

CONCLUSION(S)

The study presents a model for human blastocyst-endometrial interactions responding to an anti-P drug. The exact mechanism for the anti-attachment properties of Org 31710 on the cultured endometrial cells and the blastocysts needs further evaluations.

Attainment of peak bone mass and bone turnover rate in relation to estrous cycle, pregnancy and lactation in colony-bred Sprague-Dawley rats: suitability for studies on pathophysiology of bone and therapeutic measures for its management

Alteration in biochemical markers of bone turnover and bone mineral density (BMD) of whole body and isolated femur and tibia in relation to age, estrous cycle, pregnancy and lactation and suitability of use of rat as model for studies on pathophysiology of bone and therapeutic measures for its management were investigated. Immature rats (1, 1.5 and 2 month of age; weighing, respectively, 39.3+/-1.0, 67.8+/-2.4 and 87.2+/-5.2 g) exhibited high rate of bone turnover, as evidenced by high serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. However, their BMD (whole body or of isolated long bones) was below measurable levels. Marked increase in body weight at 3 months (185.5+/-5.2 g) was associated with low serum osteocalcin and alkaline phosphatase and urine calcium/creatinine ratio. Biochemical markers and BMD attained at puberty at 3 months were maintained until 36 month of age. No significant change in serum calcium was observed with increasing age or on any of the biomarkers during estrous cycle, and BMD of femur and tibia isolated during proestrus and diestrus stages was almost similar. Onset of pregnancy was associated with significant increase in serum total alkaline phosphatase and osteocalcin levels, but serum calcium, urine calcium/creatinine ratio or BMD of whole body or isolated long bones were not significantly different from that at proestrus stage. No marked change, except increase in body weight (P<0.05), was also evident in these parameters between days 5 and 19 of pregnancy, irrespective of number of implantations in the uterus. A significant decrease in BMD of isolated femur (neck and mid-shaft regions) was observed on days 5 and 21 of lactation as compared to that during pregnancy or diestrus/proestrus stages of estrous cycle; the decrease being almost similar in females lactating two or six young ones. BMD of isolated tibia (global and region proximal to tibio-fibular separation point), though generally lower than that during cycle and pregnancy, was statistically non-significant. However, clear evidence of occurrence of osteoporosis during lactation, with decrease in BMD of >2.5 x S.D. in isolated femur (global, neck and mid-shaft) as well as tibia (global) was observed only when BMD data was analysed on T-/Z-score basis. Serum biochemical markers of bone turnover, too, were significantly increased in comparison to cyclic rats. Findings demonstrate marked increase in body weight and bone turnover during first 3 months of age, direct correlation between peak bone mass and onset of puberty at 3 months of age and increase in bone resorption rate during lactation. Finding of the study while might suggests possible use of rat as useful model for studies on bone turnover rate during lactation and post-weaning periods and extrapolation of the result to the human situation, but not in relation to ageing.

Viviparous lizard,Eulamprus tympanum, shows changes in the uterine surface epithelium during early pregnancy that are similar to the plasma membrane transformation of mammals

The "plasma membrane transformation" describes a series of ultrastructural, biochemical, and morphological changes that occur in the uterus of many mammals at the time of blastocyst attachment. These changes, regardless of placental type or length of gestation, include alterations to microvillar length and density and the presence or absence of pinopods or uterodomes. Scanning electron microscopy (SEM) was used to 1) document the topographical ultrastructure of the uterus of Eulamprus tympanum, an eastern Australian viviparous skink with a simple chorioallantoic placenta, for the first time; and 2) determine whether changes identified as "plasma membrane transformation" in mammals occur in E. tympanum. Tissues collected over three seasons from nonreproductive subadult females, preovulatory, postovulatory, and early to mid-gestational females were examined. At low magnification the uterine epithelium of subadults displays a distinctive pattern of tissue folding that includes rectangular areas of tissue delineated by deep lateral and transverse folds. At higher magnification, the uterine epithelium surface is composed of two dominant cell types, i.e., those covered by microvilli and ciliated cells. The folding pattern observed in subadults is less evident in vitellogenic females and the cell surfaces appear highly secretory, with bulging cell apices. Tissue from postovulatory lizards has no distinctive folding pattern and cell surfaces are frequently smooth and lack microvilli. Uterine egg chambers lack ciliated cells at the embryonic pole, but display abundant secretory droplets. Thus, the uterus of E. tympanum undergoes a plasma membrane transformation. The scope of this transformation is not fully understood but may be related to the complexity of placental structure and the development of the embryo/fetus at parturition.

Human sperm-specific peptide vaccine that causes long-term reversible contraception

A novel dodecamer peptide sequence, YLP(12), was identified on human sperm that is involved in oocyte binding. We investigated its immunocontraceptive effects in a murine model. A vaccine was prepared by conjugating the synthetic YLP(12) peptide with the binding subunit of recombinant cholera toxin. Vaccination of female mice by i.m. or intranasal routes without any additional adjuvant induced a sperm-specific immune response in serum and the vaginal tract that caused a long-term contraceptive state. Fertility was fully regained when antibody reactivity diminished at 305-322 days. The contraceptive effect was also completely reversed voluntarily by intravaginal administration of the peptide. Antibodies affected fertility at the prefertilization stage by inhibiting sperm capacitation and the acrosome reaction, and sperm-oocyte binding. The peptide sequence is an epitope of a 50 +/- 5-kDa membrane protein localized on the acrosome and tail of spermatozoa. Thus, the sperm-specific YLP(12) is an attractive candidate for contraceptive vaccine.

Evaluation of interaction potential of certain concurrently administered drugs with pharmacological and pharmacokinetic profile of centchroman in rats

Centchroman (Ormeloxifene) is a nonsteroidal, selective estrogen receptor modulator, oral contraceptive and anticancer agent, and is intended for long-term use by women. In view of its vast clinical application and the interaction of steroidal oral contraceptives with certain commonly used therapeutic agents, evaluation of interaction of certain concomitantly administered therapeutic agents (ibuprofen, rifampicin, diazepam, salbutamol, nifedipine, paracetamol, haloperidol, and tetracycline), in terms of both the postcoital contraceptive efficacy and pharmacokinetic profile, with centchroman was undertaken in female Sprague-Dawley rats. Among the representatives from each commonly used therapeutic category, interaction (pharmacokinetic) was observed with ibuprofen (60 mg/kg, twice daily), haloperidol (0.7 mg/kg, twice daily), and tetracycline (140 mg/kg, twice daily) coadministration on Days 1 through 5 postcoitum. Of these three therapeutic agents, only tetracycline interfered with the contraceptive efficacy of centchroman. It reduced the bioavailability of centchroman and its active metabolite by increasing their excretion through bile and feces. Increased metabolite excretion on tetracycline coadministration indicates the enterohepatic recirculation of the metabolite, not the parent drug. However, the effect of tetracycline was negated by the inclusion of lactic acid bacillus spores in the regimen.

Maternal Hoxa10 is required for pinopod formation in the development of mouse uterine receptivity to embryo implantation

Hoxa10 is a homeobox gene that is expressed both during the embryogenesis of the genitourinary tract and in the adult reproductive tract. Maternal Hoxa10 expression is necessary for endometrial receptivity to blastocyst implantation. The mechanism by which Hoxa10 induces endometrial development to a state of receptivity is unknown as HOXA10-deficient endometrium appears histologically normal. We altered the expression of Hoxa10 in the uterus of cycling adult female mice and examined the uterus at the time of implantation by transmission electron microscopy for alterations in epithelial morphology. Pinopods are projections on the surface of the uterine endometrial epithelial cells that develop transiently at the time of endometrial receptivity. Blocking Hoxa10 expression by transfection of Hoxa10 antisense into the cycling mouse uterus before implantation dramatically decreased pinopod number. Constitutively expressing Hoxa10 in the uterus just before the normal time of pinopod formation resulted in increased pinopod number. Therefore, Hoxa10 is necessary for pinopod development. Hox genes have been implicated in both the regulation of cellular proliferation and the determination of developmental fate. Hoxa10 exemplifies this dual role in the uterus by regulating both endometrial stromal cell proliferation and epithelial cell morphogenesis. Taken together, these results demonstrate that maternal Hoxa10 has an essential role in pinopod development and this function of Hoxa10 likely contributes to endometrial receptivity for the purpose of blastocyst implantation.

Effect of antibodies to sperm-specific recombinant contraceptive vaccinogen (rCV) on murine fertilization: search for an animal model to examine its contraceptive potential

Recently, we cloned and sequenced a sperm-specific antigen, designated as Contraceptive Vaccinogen (rCV), from human testis (Naz et al., 2001). The present study was conducted to examine its proteomic homologue and function in murine sperm, in order to find out whether or not the mouse can provide a suitable model for examining its immunocontraceptive effects. This was examined by using purified antibodies (Ab) raised against the recombinant (r) human CV antigen of approximately 44 kD. In the Western blot procedure, rCV antibodies recognized a specific protein band of approximately 64 +/- 5 kD in murine testis and murine sperm extracts, the band similar to that found in human testis and human sperm. In the immunoprecipitation procedure, rCV Ab immunoprecipitated a protein band of similar size from murine sperm and murine testis extracts. The immunocytochemical (ICT), immunoscanning electronmicroscopic (ISEM) and the immunobead binding technique (IBT) revealed the subcellular localization of CV antigen on the surface of acrosome and tail regions of the noncapacitated and capacitated murine sperm cell. In functional bioassays, rCV Ab inhibited the acrosome reaction as well as sperm-egg binding in vitro. These data indicate that the CV antigen is expressed in murine sperm and has a biological role in sperm function and sperm-egg binding. In vitro inhibition of capacitation/acrosome reaction and sperm-zona binding suggest that the mouse can provide a suitable model to examine the immunocontraceptive effects of CV antigen in actively-immunized animals.

Characteristics of the uterine luminal surface epithelium at preovulatory and preimplantation stages in the marmoset monkey

Light and electron microscopy was used to examine the apical luminal epithelial surface of the uterus at preovulatory and preimplantation stages in the marmoset monkey. Luminal surface charge, detected by cationic ferritin staining, progressively decreased from preovulation to day 11 of pregnancy. The smooth, regular apical plasma membrane at preovulatory stages was in contrast to the convoluted, irregular surface observed during early pregnancy, especially at 1 day before blastocyst implantation. Profiles of microvilli were also altered, becoming thicker and more irregular during early pregnancy. Within the epithelial cell body, cyclic morphologic changes were seen, largely in association with secretory organelles. Giant phagocytic bodies were prominent at all stages examined, although their composition and intensity of staining varied throughout the cycle. Weak to moderate estrogen alpha and progesterone receptor immunostaining of the luminal epithelium was found during preovulatory and early pregnancy stages. This study describes complex cyclic changes in the morphology and biochemical make-up of the uterine luminal epithelial surface in a New World monkey in preparation for blastocyst attachment.

Centchroman, a selective estrogen receptor modulator, as a contraceptive and for the management of hormone-related clinical disorders

DL-Centchroman (67/20; INN: Ormeloxifene) synthesized at the Central Drug Research Institute, Lucknow, is a nonsteroidal once-a-week oral contraceptive. It was introduced in Delhi in July, 1991, marketed in India in 1992 as Saheli and Choice-7 (Hindustan Latex Ltd., Thiruvananthapuram) and Centron (Torrent Pharmaceuticals India Ltd., Ahmedabad), and included in the National Family Welfare Programme in 1995.5 According to post-marketing surveillance, approximately 100,000 women were using this pill and approximately 1100,000 menstrual cycles were covered until 1996. It is a unique need-oriented contraceptive being effective when taken immediately after coitus or routinely as a weekly pill and has the advantage of less frequent administration. Its contraceptive action is quickly reversible. It has long terminal serum halflife of 168 hr in women and exhibits duration of anti-implantation/estrogen antagonistic action of 120 hr, despite a short (24.1 hr) serum halflife, in the rat. In lactating women, it is excreted in milk in quantities considered unlikely to cause any deleterious effect on suckling babies. In phase II and III multicentric trials as a contraceptive, children born of method-and-user failure pregnancies showed normal milestones, without any congenital anomaly. Reports of its promising action in the management of certain hormone-related clinical disorders are available. It has an excellent therapeutic index and is considered safe for chronic administration.

Understanding the apical surface markers of uterine receptivity: pinopods-or uterodomes?

The plasma membrane of uterine epithelial cells is very sensitive to ovarian hormones and protrusions of the apical portion of this membrane have been used as indicators of endocrine status and preparation for implantation in the human uterus in particular. Protrusions of the apical plasma membrane were first identified in rats and mice where their established pinocytotic function gave rise to the name 'pinopod'. In humans and many other animals however, little evidence of the functional nature of such protrusions is available but what is available suggests that human 'pinopods' (useful though they are as indicators of endocrine status) might be more similar morphologically to other, larger, membrane protrusions, or apical domes, which have been shown not to be pinocytotic. Hence, I propose that these latter protrusions, including those in the human uterus, should be referred to by a term which does not imply a particular function and have settled on the name 'uterodome'.

Expression of alpha and gamma interferon receptors in the sperm cell

The present study was conducted to examine whether or not the sperm cell has the expression of receptors for interferon (IFN) -alpha and -gamma. This was investigated using specific antibodies. Antibody to IFN-alpha receptor reacted with the acrosomal and tail regions of the murine sperm cell in the indirect immunofluorescence technique (IFT) and immunoscanning electron microscopic procedure (ISEP). In the immunoprecipitation and Western blot procedures, this antibody specifically recognized a protein band of approximately 100 kD, which corresponds to the molecular weight of IFN-alpha receptor present in other cell types. Antibody to IFN-gamma receptor specifically reacted with the posterior head, midpiece, and tail regions of sperm cell in IFT and ISEP, and recognized a band of approximately 85 kD in the immunoprecipitation and Western blot procedures, corresponding to the IFN-alpha receptor. Similar bands of approximately 100 kD and approximately 85 kD molecular identities were also detected in the testes extracts and sperm extracts of other mammalian species namely human, rabbit, and pig, the species tested. These findings indicate that the mammalian sperm cell has expression of IFN-alpha and IFN-gamma receptors, which seem to develop during spermatogenesis in the testes. These findings may have implications in male infertility and antisperm contraceptive vaccine development.

Uterine luminal epithelial alkaline phosphatase activity and pinopod development in relation to endometrial sensitivity in the rat

The period of maximal endometrial sensitivity in the rat was characterized by high alkaline phosphatase activity in uterine luminal and glandular epithelium and endometrial stroma. The activity in endometrial stroma increased following decidualization. Pinopod development on the endometrial surface was first observed during the presensitivity period. Their number increased, apparently more so on the antimesometrial rather than the mesometrial segment of the uterus, on the day of maximal sensitivity. Inhibition in endometrial sensitivity by single anti-implantation (1.25 mg/kg, po) dose of centchroman on day 1 post-coitum (p.c.), although it did not affect alkaline phosphatase activity on days 2 and 3 p.c., caused complete inhibition in its activity in uterine luminal and glandular epithelium and pinopod development on days 4 and 5-coinciding, respectively, with time of entry of preimplantation embryos into the uterus and period of maximal endometrial sensitivity in this species. Significant decrease in enzyme activity was also evident in the entire endometrial stroma and myometrium, except blood capillaries, on these days. In comparison, prevention of entry of native embryos into the uterus by placing a ligature at the utero-tubal junction had no effect on pinopod development, but caused marked decrease in enzyme activity in luminal and glandular epithelium only during the immediate postimplantation period. The uterine lumen on the day of maximal sensitivity in centchroman-treated rats appeared highly distended and was lined with tall columnar epithelium, in comparison to low cuboidal epithelium in controls. The findings demonstrate: (a) a correlation between uterine luminal epithelial alkaline phosphatase activity and endometrial sensitivity; (b) complete inhibition in enzyme activity in luminal and glandular epithelium following centchroman treatment might be related to altered permeability characteristics of epithelial cells, which together with the absence of pinopods and highly distended uterine lumen on the day of maximal sensitivity, suggest inhibition of endocytosis/pinocytosis of luminal fluid, luminal closure, apposition of blastocyst trophoblast to luminal epithelium, and secretory activity of glandular epithelium; (c) pinopod development on the endometrial surface was independent of presence of viable blastocysts in utero; and (d) complete absence of pinopods suggests lack of endometrial sensitivity, but their presence might not necessarily indicate a sensitized endometrium in the rat.

Uterine estradiol and progesterone receptor concentration, activities of certain antioxidant enzymes and dehydrogenases and histoarchitecture in relation to time of secretion of nidatory estrogen and high endometrial sensitivity in rat

Alterations in uterine nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration, activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glucose-6-phosphate dehydrogenase (G-6-PDH) and lactate dehydrogenase (LDH), surface and transmission electron microscopy and histology in relation to the time of secretion of nidatory estrogen and the onset of endometrial sensitivity in the rat were investigated. A significant increase in plasma estradiol (E2) concentration in control rats was observed at 22.00 h on day 4 post-coitum, whereas progesterone (P) concentration increased at 17.00 h on day 4 and was maintained until 17.00 h on day 5. The period of high endometrial sensitivity (10.00 h on day 5) was characterized by elevated uterine cytosolic ER and nuclear and cytosolic PR concentration and POD activity, low columnar luminal epithelium with undulating surface and intercellular membranes, covered with short microvilli and pinopods, and containing numerous electron-transparent apical vesicles, mitochondria, polyribosomes, rough (RER) and smooth (SER) endoplasmic reticulum, well developed Golgi, few lysosomes and lipid droplets and loose edematous antimesometrial stroma. Inhibition in endometrial sensitivity by post-coital centchroman was associated with a marked depletion in uterine cytosolic ER and an increase in nuclear ER concentration, a decrease in POD and G-6-PDH activities, compact fibroblastic stroma, an increase in luminal epithelial cell height with decreased RER, SER, polyribosomes, Golgi, straightening of intercellular membranes, reduced surface undulations and absence of pinopods. Electron-transparent vesicles appeared flattened and clumped in the apical portion of cells, tight junctions were more prominent and lipid droplets were translucent. Nuclear and cytosolic PR and the pattern of secretion or plasma E2 and P remained unaffected. CAT, SOD and LDH activities, although high throughout pre-implantation, did not vary in relation to the secretion of nidatory estrogen, endometrial sensitivity or centchroman treatment.