Possible direct effect of gonadotropin releasing hormone on human endometrium and decidua

Effects of gonadotropin-releasing hormone agonist (GnRH-a) as luteal phase support in intracytoplasmic sperm injection (ICSI) cycles: a randomized controlled trial

Background

This paper describes a blind randomized controlled trial (RCT) designed to evaluate the effect of gonadotropin-releasing hormone agonist (GnRH-a) administration on outcomes of intracytoplasmic sperm injection (ICSI) in subjects stimulated with the gonadotropin-releasing hormone (GnRH) antagonist protocol. A total of 268 women who underwent ICSI cycles with GnRH antagonist ovarian stimulation protocol were included in the study. Patients were randomly assigned to the intervention (GnRH-a) and control groups. The intervention group received a single dose injection of triptorelin (0.1 mg) subcutaneously 6 days after oocyte retrieval while the control group received placebo. The rates of chemical and clinical pregnancy were defined as the primary outcome values.

Results

Two hundred forty participants accomplished the study, and their data were analyzed. No significant difference was detected between the chemical pregnancy rates of the intervention and control groups. However, the clinical pregnancy rate was significantly higher in the GnRH-a group than in the placebo group.

Conclusions

The findings of the present study suggest that the GnRH-a support in the luteal phase can result in a significant improvement of pregnancy rates in ICSI cycles following the ovarian stimulation with GnRH antagonist protocol.

Conditional loss of ERK1 and ERK2 results in abnormal placentation and delayed parturition in the mouse

Extracellular-signal-regulated kinases (ERK) 1 and 2 regulate many aspects of the hypothalamic-pituitary-gonadal axis. We sought to understand the role of ERK1/2 signaling in cells expressing a Cre allele regulated by the endogenous GnRHR promoter (GRIC-ERKdko). Adult female GRIC-ERKdko mice were hypogonadotropic and anovulatory. Gonadotropin administration and mating led to pregnancy in one-third of the ERKdko females. Litters from ERKdko females and pup weights were reduced coincident with delayed parturition and 100% neonatal mortality. Based on this, we examined Cre expression in implantation sites as a potential mechanism. GnRHR mRNA levels at e10.5 and e12.5 were comparable to pituitary levels from adult female mice at proestrus and GnRHR mRNA in decidua was enriched compared to whole implantation site. In vivo studies confirmed recombination in decidua, and GRIC-ERKdko placentas showed reduced ERK2 expression. Histopathology revealed abnormalities in placental architecture in the GRIC-ERKdko animals. Regions of apoptosis at the decidual/uterine interface at e18.5 were observed in control animals but apoptotic tone in these regions was reduced in ERKdko animals. These studies support a potential model of ERK-dependent signaling within the implantation site leading to loss of placental architecture and mis-regulation of apoptotic events at parturition occurring coincident with prolonged gestation and neonatal mortality.

GnRH antagonist for endometrial priming in an oocyte donation programme: a prospective, randomized controlled trial

RESEARCH QUESTION

Can gonadotrophin releasing hormone (GnRH) antagonist be used in egg donation recipients with ovulatory cycles for the purpose of achieving synchronization between the donor´s and recipient´s cycle?

DESIGN

Prospective randomized controlled trial to compare 7-day dosage of GnRH antagonist for endometrial priming in an oocyte donation programme with a single dose of long-acting GnRH agonist. A total of 563 women were randomized in a private single centre, and 473 women underwent embryo transfer. Ongoing pregnancy rate was the primary end point. Analysis was adjusted for embryonic stage at the time of embryo transfer; data collected included days on the waiting list; number of fresh-vitrified oocytes collected; and oocyte donor´s age at the time of retrieval.

RESULTS

No statistically significant differences were found between groups in per intention-to-treat analysis: adjusted OR 1.42 (CI 0.97 to 2.09); per treatment received: adjusted OR 1.43 (CI 0.97 to 2.09); per embryo transfer: adjusted OR for ongoing pregnancy rate 1.47 (CI 1.01 to 2.13), P = 0.047.

CONCLUSIONS

For women with ovulatory cycles undergoing oocyte donation, the outcomes are similar between GnRH antagonist and down-regulated hormone replacement protocols.

Evaluation of the impact of gonadotropin-releasing hormone agonist as an adjuvant in luteal-phase support on IVF outcome

OBJECTIVES:

To evaluate whether three daily doses of GnRH agonist (Inj. Lupride 1 mg SC) administered 6 days after oocyte retrieval increases ongoing pregnancy rates following embryo transfer (ET) in cycles stimulated with the long GnRH agonist protocol.

SETTINGS AND DESIGN:

Prospective randomized controlled study in a tertiary care center.

MATERIALS AND METHODS:

Four hundred and twenty six women undergoing ET following controlled ovarian stimulation with a long GnRH agonist protocol were included. In addition to routine luteal-phase support (LPS) with progesterone, women were randomized to receive three 1 mg doses of Lupride 6 days after oocyte retrieval. Computer-generated randomization was done on the day of ET. Ongoing pregnancy rate beyond 20^th week of gestation was the primary outcome measure. The trial was powered to detect a 13% absolute increase from an assumed 27% ongoing pregnancy rate in the control group, with an alpha error level of 0.05 and a beta error level of 0.2.

RESULTS:

There were 59 (27.69%) ongoing pregnancies in the GnRHa group, and 56 (26.29%) in the control group (P = 0.827). Implantation, clinical pregnancy and multiple pregnancy rates were likewise similar in the GnRHa and placebo groups.

CONCLUSIONS:

Three 1 mg doses of Lupride administration 6 days after oocyte retrieval in the long protocol cycles does not result in an increase in ongoing pregnancy rates.

Effects of gonadotrophin releasing hormone analogues on human endometrial stromal cells and embryo invasion in vitro

BACKGROUND

Gonadotrophin releasing hormone (GnRH) analogues are widely used in IVF programmes as a method of suppressing the luteinizing hormone (LH) surge prior to ovarian stimulation, but their roles outside the pituitary remain relatively unknown. A 2002 Cochrane review (Al-Inany et al. Gonadotrophin-releasing hormone antagonists for assisted conception. Cochrane Database Syst Rev 2006;3:CD001750) described lower pregnancy rates in women administered with GnRH antagonist, compared with those using an agonist, as part of an IVF programme, despite the fact that GnRH antagonist is a more effective repressor of LH. This study aimed to analyse the in-vitro effects of GnRH analogues on the decidualizing endometrium, blastocyst invasion and GnRH receptor expression in fertile women.

METHODS

We analysed the in-vitro decidualization capacity of endometrial stromal cells, derived from fertile women during the implantation window, in the presence of GnRH analogues. The influence of GnRH analogues on GnRH receptor expression and blastocyst invasion was assessed by in-vitro assays of biomedical marker secretion, immunoblots and blastocyst attachment to the stromal extracellular matrix.

RESULTS

We demonstrate that, at the concentrations and time periods used, GnRH analogues did not significantly influence the extent of decidualization of endometrial stromal cells. In addition, no adverse effect of GnRH analogues was seen on human blastocyst invasion.

CONCLUSIONS

We suggest that GnRH analogues affect neither the capacity of the endometrium to support invasion nor the invasive potential of the blastocyst in the early stages of implantation.

The effects of GnRH antagonist on the endometrium of normally menstruating women

PURPOSE

To study the effects of GnRH antagonist (ganirelix-Orgalutran) on the endometrium of regularly menstruating women.

MATERIALS AND METHODS

Prospective, self-controlled study. The thirty-five volunteers were studied for two cycles: one as a control and the other, GnRH antagonist-treated cycles in which ganirelix 0.25 mg/d was given daily for 3 days, starting when the largest follicle reached 15 mm. In both cycles, serum estradiol, LH and endometrial thickness were measured when the largest follicle was > or =18 mm. Endometrial biopsy was performed on day 6 after ovulation for histological dating and morphometric study.

RESULTS

No statistical differences between histological dating and the endometrial thickness in the control and GnRH antagonist-treated cycles. All morphometric parameters were also not different. Serum estradiol and LH levels were significantly lower in GnRH antagonist-treated cycles.

CONCLUSION

GnRH antagonist has no effect on the endometrium of regularly menstruating women as assessed by either histological dating or morphometric analysis.

Effects of gonadotropin-releasing hormone agonists and antagonists on luteal function

PURPOSE OF REVIEW

This review addresses the effects of gonadotropin-releasing hormone agonists and antagonists on various aspects of the luteal phase.

RECENT FINDINGS

Recent studies have shown that use of both gonadotropin-releasing hormone agonists and antagonists during in-vitro fertilization cycles leads to alterations in the hormonal profiles of the luteal phase as well as changes in endometrial histology. Gonadotropin-releasing hormone agonists are effective in triggering final oocyte maturation and reducing the incidence of ovarian hyperstimulation syndrome. Ongoing pregnancy rates are excellent after gonadotropin-releasing hormone agonist trigger when luteal phase and early pregnancy supplementation with estradiol and progesterone is provided. Gonadotropin-releasing hormone agonists have recently been used for luteal phase support in in-vitro fertilization cycles.

SUMMARY

Although gonadotropin-releasing hormone agonists and antagonists are clinically useful, they may have adverse effects on luteal function. Luteal phase supplementation significantly improves clinical outcomes in in-vitro fertilization cycles because it may correct some of these detrimental effects. Use of gonadotropin-releasing hormone agonist to induce oocyte maturation is beneficial to patients who are at increased risk for ovarian hyperstimulation syndrome. The key factor in achieving favorable ongoing pregnancy rates with use of gonadotropin-releasing hormone agonist to induce oocyte maturation appears to be adequate luteal phase support.

Expression of L-selectin ligands in human endometrium during the implantation window after controlled ovarian stimulation for oocyte donation

L-selectin ligands were detected in the epithelial endometrium throughout the implantation window, whereas the level of expression was significantly reduced in the donor versus control group on cycle day 19 (P<.05) in the luminal epithelium and during cycle days 19-24 in the glandular epithelium. Controlled ovarian stimulation, using the antagonist protocol in this study, is associated with a reduction of L-selectin ligand expression during the implantation window which may adversely affect the endometrial environment.

The biology of gonadotropin hormone-releasing hormone: role in the control of tumor growth and progression in humans

It is now well known that different forms of GnRH coexist in the same vertebrate species. In humans, two forms of GnRH have been identified so far. The first form corresponds to the hypophysiotropic decapeptide, and is now called GnRH-I. The second form has been initially identified in the chicken brain, and it is referred to as GnRH-II. GnRH-I binds to and activates specific receptors, belonging to the 7 transmembrane (7TM) domain superfamily, present on pituitary gonadotropes. These receptors (type I GnRH receptors) are coupled to the Gq/11/PLC intracellular signalling pathway. A receptor specific for GnRH-II (type II GnRH receptor) has been identified in non-mammalian vertebrates as well as in primates, but not yet in humans. In the last 10-15 years experimental evidence has been accumulated indicating that GnRH-I is expressed, together with its receptors, in tumors of the reproductive tract (prostate, breast, ovary, and endometrium). In these hormone-related tumors, activation of type I GnRH receptors consistently decreases cell proliferation, mainly by interfering with the mitogenic activity of stimulatory growth factors (e.g., EGF, IGF). Recent data seem to suggest that GnRH-I might also reduce the migratory and invasive capacity of cancer cells, possibly by affecting the expression and/or activity of cell adhesion molecules and of enzymes involved in the remodelling of the extracellular matrix. These observations point to GnRH-I as an autocrine negative regulatory factor on tumor growth progression and metastatization. Extensive research has been performed to clarify the molecular mechanisms underlying the peculiar antitumor activity of GnRH-I. Type I GnRH receptors in hormone-related tumors correspond to those present at the pituitary level in terms of cDNA nucleotide sequence and protein molecular weight, but do not share the same pharmacological profile in terms of binding affinity for the different synthetic GnRH-I analogs. Moreover, the classical intracellular signalling pathway mediating the stimulatory activity of the decapeptide on gonadotropin synthesis and secretion is not involved in its inhibitory activity on hormone-related tumor growth. In these tumors, type I GnRH receptors are coupled to the Gi-cAMP, rather than the Gq/11-PLC, signal transduction pathway. Recently, we have reported that GnRH-I and type I GnRH receptors are expressed also in tumors not related to the reproductive system, such as melanoma. Also in melanoma cells, GnRH-I behaves as a negative regulator of tumor growth and progression. Interestingly, the biochemical and pharmacological profiles of type I GnRH receptors in melanoma seem to correspond to those of the receptors at pituitary level. The data so far reported on the expression and on the possible functions of GnRH-II in humans are still scanty. The decapeptide has been identified, together with a 'putative' type II GnRH receptor, both in the central nervous system and in peripheral structures, such as tissues of the reproductive tract (both normal and tumoral). The specific biological functions of GnRH-II in humans are presently under investigation.

Differential effects of gonadotropin-releasing hormone I and II on the urokinase-type plasminogen activator/plasminogen activator inhibitor system in human decidual stromal cells in vitro

To date, the factors capable of regulating the coordinate expression of the urokinase-type plasminogen activator (uPA) and its endogenous inhibitor, plasminogen activator inhibitor (PAI-1), at the maternal-fetal interface remain poorly characterized. In these studies we examined the ability of the classical form of gonadotropin-releasing hormone (GnRH) I and the second, mammalian form of this hormone, GnRH II, to regulate uPA and PAI-1 mRNA and protein expression levels in cultures of stromal cells isolated from first trimester decidual tissues using quantitative competitive-PCR and ELISA, respectively. GnRH I and GnRH II increased uPA mRNA and protein expression levels in these primary cell cultures in a dose- and time-dependent manner. In contrast, GnRH I increased, whereas GnRH II decreased PAI-1 mRNA and protein expression levels in these cells. Cetrorelix, a GnRH receptor antagonist, inhibited the regulatory effects of GnRH I, but not GnRH II, on uPA and PAI-1 expression levels in these decidual stromal cell cultures. Taken together, these observations suggest that GnRH I and GnRH II differentially regulate the balance between uPA and PAI-1 expression levels in the human decidua, possibly via distinct receptor-mediated signaling pathways.

Gonadotrophin-releasing hormone antagonists: will they replace the agonists?

Modern gonadotrophin-releasing hormone (GnRH) antagonists such as cetrorelix and ganirelix reliably prevent premature LH surges in controlled ovarian hyperstimulation for assisted reproductive technologies. Cetrorelix and ganirelix are safe and effective compounds. Because of their distinct pharmacological mode of action, it has been possible to achieve a significant reduction of treatment time. Fertilization and pregnancy rates are comparable to those obtained in agonist protocols for ovarian stimulation. No allergic or hyperergic reactions have been reported, and patient compliance is excellent. The fact that GnRH antagonists allow an immediate suppression of gonadotrophin concentrations while preserving pituitary responsiveness to endogenous GnRH provides enormous flexibility in treatment. GnRH antagonists have helped to overcome some major disadvantages of GnRH agonists, especially of the long protocol, which is currently the standard protocol for ovarian stimulation. The mistaken administration of antagonists during early pregnancy is not possible, since they are only administered during ovarian stimulation when a premature LH surge may be imminent. They are used in the spontaneous cycle or after pretreatment with oral contraceptives. Pregnancy can easily be ruled out by testing for human gonadotrophic hormone before onset of gonadotrophin stimulation on the second or third day of the cycle. Since flare-up effects are absent, there is no risk of cyst formation. Hormonal withdrawal symptoms are eliminated, since no period of pituitary suppression occurs, and therefore exogenous gonadotrophins are not required. Overall, the duration of the stimulation cycle is as short as a normal menstrual cycle. The procedure seems to be safer than the long protocol, since the most serious complication, the occurrence of severe cases of OHSS, is reduced. It is also safe with respect to the course of pregnancies and the health of offspring. Both protocols developed so far, the single dose and multiple dose antagonist protocol, are comparable, utilizing data from the large prospective phase IIIb studies. Although several studies have indicated a slight reduction in pregnancy rate with GnRH antagonists as compared with agonists, this problem may be rectified by developing flexible antagonist regimens designed for individual patients. Introducing flexible GnRH antagonist regimens should be the area of research in the near future.

Prospective, randomized, controlled study of in vitro fertilization-embryo transfer with a single dose of a luteinizing hormone-releasing hormone (LH-RH) antagonist (cetrorelix) or a depot formula of an LH-RH agonist (triptorelin)

OBJECTIVE

To confirm the value of a single dose of 3 mg of cetrorelix in preventing the occurrence of premature LH surges.

DESIGN

Multicenter randomized, prospective study.

SETTING

Reproductive medicine units.

PATIENT(S)

Infertile patients undergoing ovarian stimulation for IVF-ET.

INTERVENTION(S)

A single dose of 3 mg of cetrorelix (Cetrotide; ASTA Medica, Frankfurt, Germany) (115 patients) was administered in the late follicular phase. A depot preparation of triptorelin (Decapeptyl; Ipsen-Biotech, Paris, France) was chosen as a control agent (39 patients). Ovarian stimulation was conducted with hMG (Menogon; Ferring, Kiel, Germany).

MAIN OUTCOME MEASURE(S)

Premature LH surges (LH level >10 IU/L), progesterone level greater than 1 ng/L, and IVF results.

RESULT(S)

No LH surge occurred after cetrorelix administration. The patients in the cetrorelix group had a lower number of oocytes and embryos. The percentage of mature oocytes and fertilization rates were similar in both groups, and the pregnancy rates were not statistically different. The length of stimulation, number of hMG ampules administered, and occurrence of the ovarian hyperstimulation syndrome were lower in the cetrorelix group. Tolerance of cetrorelix was excellent.

CONCLUSION(S)

A cetrorelix single-dose protocol prevented LH surges in all patients studied. It compares favorably to the "long protocol" and could be a protocol of choice in IVF-ET.

Independent regulation of matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and TIMP-3 in human endometrial stromal cells by gonadotropin-releasing hormone: implications in early human implantation

Early human trophoblast shows dramatic invasive properties during early pregnancy. The simultaneous synthesis of matrix metalloproteinases (MMPs) and their specific tissue inhibitors (TIMPs) in both human trophoblast and decidual membranes suggests that their controlled and balanced expression is crucial for the rapid matrix remodeling and controlled invasion during early pregnancy. Recently, we have described the presence of an extrahypothalamic GnRH immunologically, biologically and chemically identical to the hypothalamic hormone in periimplantation human embryos. Moreover, the production of this decapeptide by the human trophoblast during the early stages of placentation is well documented. TIMP-1 and -3 messenger ribonucleic acid (mRNA) expression in cultured stromal cells and protein secretion into the medium were significantly decreased by GnRH agonist compared to that in control groups. Moreover, expression of TIMP-1 was affected to a greater extent than that of TIMP-3. GnRH antagonist ablated the down-regulation of TIMPs by the GnRH agonist. MMP-9 mRNA expression was not detected in the control groups or in the groups treated with GnRH analogs. Our results provide evidence that trophoblastic GnRH may play an important role in placental tissue organization and in the early embryo-maternal dialogue by enhancing trophoblast invasion through the specific inhibition of TIMPs.