Actin binding protein expression is altered in uterine luminal epithelium by clomiphene citrate, a synthetic estrogen receptor modulator

Effect of Endometrium Thickness on Clinical Outcomes in Luteal Phase Short-Acting GnRH-a Long Protocol and GnRH-Ant Protocol

OBJECTIVE

To investigate the factors that influence luteal phase short-acting gonadotropin-releasing hormone agonist (GnRH-a) long protocol and GnRH-antagonist (GnRH-ant) protocol on pregnancy outcome and quantify the influence. About the statistical analysis, it is not correct for the number of gravidities.

METHODS

Infertile patients (n = 4,631) with fresh in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) and embryo transfer were divided into GnRH-a long protocol (n =3,104) and GnRH-ant (n =1,527) protocol groups and subgroups G1 (EMT ≤7mm), G2 (7 mm <EMT ≤10 mm), and G3 (EMT >10 mm) according to EMT on the trigger day. The data were analyzed.

RESULTS

The GnRH-ant and the GnRH-a long protocols had comparable clinical outcomes in the clinical pregnancy, live birth, and miscarriage rate after propensity score matching. In the medium endometrial thickness of 7-10 mm, the clinical pregnancy rate (61.81 vs 55.58%, P < 0.05) and miscarriage rate (19.43 vs 12.83%, P < 0.05) of the GnRH-ant regime were significantly higher than those of the GnRH-a regime. The EMT threshold for clinical pregnancy rate in the GnRH-ant group was 12 mm, with the maximal clinical pregnancy rate of less than 75% and the maximal live birth rate of 70%. In the GnRH-a long protocol, the optimal range of EMT was >10 mm for the clinical pregnancy rate and >9.5 mm for the live birth rate for favorable clinical outcomes, and the clinical pregnancy and live birth rates increased linearly with increase of EMT. In the GnRH-ant protocol, the EMT thresholds were 9-6 mm for the clinical pregnancy rate and 9.5-15.5 mm for the live birth rate.

CONCLUSIONS

The GnRH-ant protocol has better clinical pregnancy outcomes when the endometrial thickness is in the medium thickness range of 7-10 mm. The optimal threshold interval for better clinical pregnancy outcomes of the GnRH-ant protocol is significantly narrower than that of the GnRH-a protocol. When the endometrial thickness exceeds 12 mm, the clinical pregnancy rate and live birth rate of the GnRH-ant protocol show a significant downward trend, probably indicating some negative effects of GnRH-ant on the endometrial receptivity to cause a decrease of the clinical pregnancy rate and live birth rate if the endometrial thickness exceeds 12 mm.

Clomiphene citrate impairs the endometrial CD98 expression in ovariectomized and non-ovariectomized rats: Role of HCG

Background

Clomiphene citrate (CC) is one of the widely used drugs as an ovulation stimulant, but its adverse effects on the endometrium results in lowering down the pregnancy rate. Endometrium CD98 is also important in the process of implantation.

Objective

To evaluate the immunohistochemistry expression levels of endometrial CD98 following injection of CC with and without Human chorionic gonadotropin (HCG) in ovariectomized and non-ovariectomized rats.

Materials and Methods

Seventy two (12-14 wk old) female Wistar rats were randomly divided into two groups (n = 36): (a) ovariectomized and (b) non-ovariectomized. Each group was further divided into six subgroups (n = 6/each): (1) CC 10 mg/kg, (2) CC 20 mg/kg, (3) HCG, (4) CC 10 mg/kg with HCG, (5) CC 20 mg/kg with HCG, and (6) control. The experimental subgroups received a single dose of CC (daily, five days) and HCG (after the last injection of CC) alone or in combination. Immunohistochemistry staining was performed on paraffin-embedded endometrial tissues to evaluate the expression levels of CD98.

Results

Animals undergoing ovariectomy presented a significantly lower expression level of endometrial CD98 (p < 0.001) when compared with non-ovariectomized in the same condition that groups were subdivided. There was also a dose-dependent reduction (p < 0.001) in the expression of CD98 in non-ovariectomized subgroups when compared with control group. In addition, injection of HCG following treatment with CC improved its expression.

Conclusion

It was concluded that CC impairs CD98 expression in endometrium and this impairment is intensified with the removal of the ovary. Also, an injection of HCG following treatment with CC can slightly improve the expression of CD98.

Alterations in the distribution of actin and its binding proteins in the porcine endometrium during early pregnancy: Possible role in epithelial remodeling and embryo adhesion

During early pregnancy, uterine epithelial cells undergo major transformations in their cytoskeleton that make the endometrium receptive for conceptus attachment. Actin binding proteins (ABPs) such as cofilin, gelsolin, and vinculin are involved in regulating actin polymerization, severing or crosslinking actin to integrins. However, whether ABPs are involved in epithelial remodeling or embryo adhesion in pigs is unknown. Therefore, the expression and distribution of these proteins were investigated in porcine endometrium on Days 10 and 13 (pre-implantation period), and 16 (attachment phase) of the estrous cycle or pregnancy. While day and pregnancy status had no effect on ABP gene expression, the protein abundance of vinculin was significantly higher on Day 13 than on Day 10 (p < 0.05) of the estrous cycle, and its abundance was highest on Day 16 in the pregnant endometrium. Immunofluorescent staining showed alterations in the distribution of these proteins depending on the day of the estrous cycle or early pregnancy examined. Double immunofluorescent staining for the ABPs and actin revealed that while cofilin co-localized with actin in the apical epithelium on Days 13 and 16 of the estrous cycle, in pregnant animals, it was strongly associated with actin in the sub-epithelial stroma of the endometrium. Gelsolin was also co-localized with actin in the apical epithelium on Days 13 and 16 of the estrous cycle, but this association was absent in the pregnant endometrium. Vinculin co-localized with actin in the sub-epithelial stroma on Days 13 and 16 irrespective of the reproductive status, but was additionally associated with actin in the apical epithelium on Day 16 of pregnancy. Vinculin interacted with phosphorylated focal adhesion kinase in the endometrial epithelium, and the interaction was dependent on estradiol-17β, a conceptus-secreted pregnancy-recognition factor in pigs. Furthermore, silencing vinculin in the endometrial epithelial cells negatively affected trophoblast adhesion to them. In conclusion, the influence of stage and reproductive status on the specific localization of actin and its binding proteins in the porcine endometrium suggests that they play a role in regulating the endometrial cytoskeleton. Moreover, vinculin may facilitate conceptus attachment to the epithelium by interacting with focal adhesion kinase.

Stromal cell-specific apoptotic and antiestrogenic mechanisms may explain uterine defects in humans after clomiphene citrate therapy

OBJECTIVE

The purpose of this study was to investigate clomiphene citrate (CC)-induced modulation of uterine cell function in vivo.

STUDY DESIGN

Prepubertal female Sprague-Dawley rats were treated intraperitoneally with CC for 6 or 24 hours or with a combination of CC and/or 17-beta-estradiol (E2) for 4 days.

RESULTS

Chronic CC treatment induced apoptosis in a fraction of uterine stromal cells by activating the caspase-3-mediated apoptotic pathway. The damage was prevented by successive E2 treatment; however, pretreatment or concomitant treatment with E2 did not protect against CC-induced uterine apoptosis. CC decreased the protein expression of estrogen receptor alpha and increased its phosphorylation but did not affect estrogen receptor beta expression or phosphorylation. Furthermore, changes in Hoxa11, p27, and progesterone receptor protein levels and localization were associated with CC treatment.

CONCLUSION

We provide novel mechanistic insights into cellular and molecular events by which CC regulates uterine stromal cell function and hence the implantation process and pregnancy outcome.

A new approach to understanding the molecular mechanisms through which estrogens affect cognition

Traditional approaches to the study of hormones and cognition have been primarily observational or correlational in nature. Because this work does not permit causal relationships to be identified, very little is known about the specific molecules and cellular events through which hormones affect cognitive function. In this review, we propose a new approach to study hormones and memory, where the systematic blocking of cellular events can reveal which such events are necessary for hormones to influence memory consolidation. The discussion will focus on the modulation of the hippocampus and hippocampal memory by estrogens, given the extensive literature on this subject, and will illustrate how the application of this approach is beginning to reveal important new information about the molecular mechanisms through which estrogens modulate memory consolidation. The clinical relevance of this work will also be discussed.

The effects of acute 17beta-estradiol treatment on gene expression in the young female mouse hippocampus

Previous studies have demonstrated that treatment with 17beta-estradiol (E(2)) improves both spatial and nonspatial memory in young female mice. Still unclear, however, are the molecular mechanisms underlying the beneficial effects of E(2) on memory. We have previously demonstrated that a single post-training intraperitoneal (i.p.) injection of 0.2 mg/kg E(2) can enhance hippocampal-dependent spatial and object memory consolidation (e.g., Gresack & Frick, 2006b). Therefore, in the present study, we performed a microarray analysis on the dorsal hippocampi of 4-month-old female mice injected i.p. with vehicle or 0.2 mg/kg E(2). Genes were considered differentially expressed following E(2) treatment if they showed a greater than 2-fold change in RNA expression levels compared to controls. Overall, out of a total of approximately 25,000 genes represented on the array, 204 genes showed altered mRNA expression levels upon E(2) treatment, with 111 up-regulated and 93 down-regulated. Of these, 17 of the up-regulated and 6 of the down-regulated genes are known to be involved in learning and memory. mRNA expression changes in 5 of the genes were confirmed by real-time quantitative PCR analysis, and protein changes in these same genes were confirmed by Western blot analysis: Hsp70, a heat shock protein known to be estrogen responsive; Igfbp2, an IGF-I binding protein; Actn4, an actin binding protein involved in protein trafficking; Tubb2a, the major component of microtubules; and Snap25, a synaptosome-specific protein required for neurotransmitter release. The types of genes altered indicate that E(2) may induce changes in the structural mechanics of cells within the dorsal hippocampus that could be conducive to promoting memory consolidation.