Inhibition of progesterone secretion with trilostane for mid-trimester termination of pregnancy: randomized controlled trials

Progesterone-mediated remodeling of the maternal-fetal interface by a PGRMC1-dependent mechanism

Implantation and maintenance of pregnancy involve intricate immunological processes that enable the developing fetus to coexist with the maternal immune system. Progesterone, a critical hormone during pregnancy, is known to promote immune tolerance and prevent preterm labor. However, the mechanism by which progesterone mediates these effects remains unclear. In this study, we investigated the role of the non-classical progesterone receptor membrane component 1 (PGRMC1) in progesterone signaling at the maternal-fetal interface. Using JEG3 cells, a trophoblast model cell line, we observed that progesterone stimulation increased the expression of human leukocyte antigen-C (HLA-C) and HLA-G, key molecules involved in immune tolerance. We also found that progesterone upregulated the expression of the transcription factor ELF3, which is known to regulate trophoblast-specific HLA-C expression. Interestingly, JEG3 cells lacked expression of classical progesterone receptors (PRs) but exhibited high expression of PGRMC1, a finding we confirmed in primary trophoblasts by mining sc-RNA seq data from human placenta. To investigate the role of PGRMC1 in progesterone signaling, we used CRISPR/Cas9 technology to knockout PGRMC1 in JEG3 cells. PGRMC1-deficient cells showed a diminished response to progesterone stimulation. Furthermore, we found that the progesterone antagonist RU486 inhibited ELF3 expression in a PGRMC1-dependent manner, suggesting that RU486 acts as a progesterone antagonist by competing for receptor binding. Additionally, we found that RU486 inhibited cell invasion, an important process for successful pregnancy, and this inhibitory effect was dependent on PGRMC1. Our findings highlight the crucial role of PGRMC1 in mediating the immunoregulatory effects of progesterone at the maternal-fetal interface.

Inhibition of Resveratrol Analogs on Human and Rat 3β-Hydroxysteroid Dehydrogenases: Structure-Activity Relationship and Docking Analysis

Resveratrol and its analogs are phytochemicals. Human 3β-hydroxysteroid dehydrogenase 1 (3β-HSD1) synthesizes steroid hormones for normal pregnancy or promoting cancer metastasis. Whether they inhibit 3β-HSD1 remains unclear. In this study, the inhibitory potency, mode of action, structure-activity relationship, and docking parameters of resveratrol and its analogs on 3β-HSD1 and rat homolog 3β-HSD4 were analyzed. The inhibitory potency of these chemicals on human 3β-HSD1 was 4,4'-dihydroxystilbene (IC₅₀, 3.68 μM) > pinostilbene (8.07 μM) > pinosylvin (10.60 μM) > lunularin (26.84 μM) > resveratrol (30.20 μM) > dihydroresveratrol (>100 μM) = oxyresveratrol (>100 μM) > dihydropinosylvin (ineffective at 100 μM). Resveratrol analogs and metabolites are mixed or competitive inhibitors of human 3β-HSD1. Resveratrol and 4,4'-dihydroxystilbene inhibited progesterone secretion by human JAr cells at ≥1 μM. Resveratrol (IC₅₀, 32.09 μM) and pinosylvin (34.71 μM) significantly inhibited rat placental 3β-HSD4 activity. Docking analysis shows that resveratrol analogs and metabolites bind the steroid-binding sites of human 3β-HSD1 and rat 3β-HSD4 and interact with the catalytic residues Ser125/Thr125 and Tyr155. The negative correlation of LogP and IC₅₀ values for human 3β-HSD1 indicates that lipophilicity of chemicals plays a critical role in the inhibitory effect of chemicals. In conclusion, 4,4'-dihydroxystilbene, pinostilbene, and pinosylvin effectively inhibit human 3β-HSD1 depending on their lipophilicity, thereby acting as potential therapeutic agents.

The Efficacy of a 3β-Hydroxysteroid Dehydrogenase Inhibitor for the Termination of Mid-Term Pregnancies in Dogs

Simple Summary

The medical termination of unwanted pregnancies in dogs is practiced throughout the world for many reasons, including at the request of animal owners. For these procedures, it is advised to use rapidly effective drugs with minimal side effects. In this study, we investigated trilostane, which decreases progesterone levels, for its efficacy in terminating mid-term pregnancies in dogs, as well as potential side effects. Although trilostane is not a standalone alternative for the termination of pregnancy in dogs, it has been determined that its combined use with another medical agent of known efficacy reduces both the abortion time and potential side effects. Further studies investigating an increased frequency of administration rather than the administration dose could contribute to determining the efficacy of trilostane in dogs.

Abstract

Progesterone (P4) is the only hormone needed to maintain pregnancy in dogs. Therefore, a competitive inhibitor of 3β-hydroxysteroid dehydrogenase (3β-HSD) could be a safe and effective option to terminate pregnancy by inhibiting P4 synthesis. To address this hypothesis, we investigated the efficacy of trilostane (TRL), a competitive inhibitor of 3β-HSD, in terminating pregnancy in dogs. Twenty-one dogs between days 30 and 38 of pregnancy were randomly assigned to one of two treatment groups (trilostane (TRL) and aglepristone (AGL)) and an untreated control (CON) group (n = 7 dogs each). Fetal heart rates (FHRs) (measured at 12 h intervals) and serum P4 concentrations (measured at 6 h intervals) were evaluated. The pregnancy termination rates were 0% and 100% in the TRL and AGL groups, respectively. The decrease in the FHR in the TRL and AGL groups was significantly lower than that observed in the CON group. There was a marked decrease in P4 concentrations in the TRL group 6, 54, and 102 h after the initiation of treatment. The luteal expression of StAR appeared to be weaker in the AGL group than the CON group. In conclusion, although a treatment-induced decrease was observed in plasma P4 concentrations, a seven-day TRL treatment alone was not effective in terminating pregnancies. Further studies are needed on the effects of the prolonged administration of TRL with varying doses and frequencies for the termination of mid-term pregnancy in dogs.

Altered redox homeostasis in steroid-depleted follicles attenuates hCG regulation of follicular events: Cross-talk between endocrine and IGF axis in maturing oocytes

Steroids and insulin-like growth factors (Igfs) are indispensable for folliculogenesis and reproductive fitness in the vertebrate ovary. The intrafollicular redox balance is also of immense importance for ovarian follicles wherein low levels of ROS are being utilized for cell signalling and regulation of gene expression; its excess may interfere with normal physiological processes leading to ovotoxicity. However, the functional relevance of ovarian steroidogenesis in maintaining the follicular microenvironment with coordinated redox homeostasis and intra-ovarian growth factors axis is relatively less understood. Using zebrafish full-grown (FG) ovarian follicles in vitro, our study shows that blocking steroid biosynthesis with anti-steroidal drugs, DL-aminoglutethimide (AG) or Trilostane (Trilo), prevents hCG (LH analogue)-induced StAR expression concomitant with a robust increase in intrafollicular ROS levels. Congruent with heightened intracellular levels of superoxide anions (O₂^•-) and hydrogen peroxide (H₂O₂), priming with AG or Trilo abrogates the transcript abundance of major antioxidant enzyme genes (SOD1, SOD2, and CAT) in hCG-stimulated follicles. Significantly, blocking steroidogenesis attenuates transcript abundance of HSP70 but elevates NOX4 expression potentially through ERα-mediated pathway. Importantly, disrupted redox balance in AG/Trilo pre-incubated FG follicles negatively impacts hCG-mediated activation of PKA/CREB signaling and transcriptional activation of igf ligands. Elevated ROS attenuation of antioxidant defense parameters and impaired endocrine and autocrine/paracrine homeostasis converge upon reduced p34cdc2 (Thr-161) phosphorylation, a reliable marker for MPF activation, and resumption of meiotic G2-M1 transition in hCG-treated follicles. Collectively, altered redox homeostasis in steroid-depleted follicles has a significant negative influence on GTH (LH) regulation of follicular events, specifically Igf synthesis, meiotic maturational competence and ovarian fitness.

Assisted reproduction technologies alter steroid delivery to the mouse fetus during pregnancy

Assisted reproduction technologies (ART) include in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI), and are common treatments for infertility. Although generally successful, ART warrant further investigations due to emerging perinatal issues, especially low birth weight. Herein we extend our previous work demonstrating higher steroid clearance in murine ART placentas by examining steroid biosynthesis and the directional flow of steroids in the maternal-placental-fetal units. The activities of the major steroidogenic enzymes 3β-hydroxysteroid dehydrogenase (3β-HSD) and cytochrome P450 17-αhydroxylase (CYP17) were assessed in maternal liver and ovaries and fetal livers as were levels of cholesterol, progesterone, estrone (E1), and estradiol (E2) in the maternal, placental and fetal units. No structural abnormalities were found in placentas from ART. Although ART increased 3β-HSD activity in maternal livers, there were no other changes in 3β-HSD- or CYP17-mediated steroidogenesis. Cholesterol levels were significantly lower in maternal livers of ICSI pregnancies and in placentas from both IVF and ICSI pregnancies but not altered in the fetal livers. Progesterone levels were higher in maternal and fetal livers in IVF and ICSI, respectively, but were significantly lowered in ICSI placentas, compared to normal fertilization. For estrogenic hormones, no differences in E1 or E2 levels were observed in maternal livers but ICSI significantly increased both E1 and E2 levels in placentas while both IVF and ICSI significantly lowered E1 but raised E2 levels in fetal livers. In summary, while steroid production was normal, steroid diffusion/flow from mother to fetus was altered in murine pregnancies conceived by ART. This appears to occur, at least in part; through placental mechanisms. Impaired cholesterol and steroid transfer may affect correct regulation of fetal growth and development.

Medical methods for mid-trimester termination of pregnancy

BACKGROUND

With the improvement of ultrasound technology, the likelihood of detection of major fetal structural anomalies in mid-pregnancy has increased considerably. Upon the detection of serious anomalies, women typically are offered the option of pregnancy termination. Additionally, there are still many reasons other than fetal anomalies why women seek abortion in the mid-trimester.

OBJECTIVES

To compare different methods of second trimester medical termination of pregnancy for their efficacy and side-effects.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), MEDLINE, Popline and reference lists of retrieved papers and other sources.

SELECTION CRITERIA

All randomised controlled trials (RCTs) examining medical regimens for termination of pregnancy of a singleton living fetus between 12-28 weeks' gestation were analysed. The outcome measures were the induction to abortion interval, abortion rate within 24 hours, need for surgical evacuation, blood loss, uterine rupture, pain, and side-effects.Trials including >20% fetal death, multiple pregnancies, previous uterine scars and regimens which involved cervical preparation were excluded.

DATA COLLECTION AND ANALYSIS

Two authors selected the trials and three authors extracted data.

MAIN RESULTS

Fourty RCTs were included, addressing various agents for pregnancy termination and methods of administration. When used alone, misoprostol was an effective inductive agent, though it appeared to be more effective in combination with mifepristone. However, the evidence from RCTs is limited.Misoprostol was preferably administered vaginally, although among multiparous women sublingual administration appeared equally effective. A range of doses of vaginally administered misoprostol has been used. No randomised trials comparing doses of misoprostol were identified; however low doses of misoprostol appear to be associated with fewer side-effects while moderate doses appear to be more efficient in completing abortion. Four RCTs showed that the induction to abortion interval with 3-hourly vaginal administration of prostaglandins is shorter than 6-hourly administration without an increase in side-effects.Many studies reported the need for surgical evacuation. Indications for surgical evacuation include retained products of the placenta and heavy vaginal bleeding. Fewer women required surgical evacuation when misoprostol was administrated vaginally compared with women receiving intra-amniotical PGF(2a) . Mild, self-limiting diarrhoea was more common among women who received misoprostol compared to other agents.

AUTHORS' CONCLUSIONS

Medical abortion in the second trimester using the combination of mifepristone and misoprostol appeared to have the highest efficacy and shortest abortion time interval. Where mifepristone is not available, misoprostol alone is a reasonable alternative. The optimal route for administering misoprostol is vaginally, preferably using tablets at 3-hourly intervals. Apart from pain, the side-effects of vaginal misoprostol are usually mild and self limiting. Conclusions from this review are limited by the gestational age ranges and variable medical regimens, including dosing, administrative routes and intervals of medication, of the included trials.

Induction of progesterone receptor A form attenuates the induction of cytosolic phospholipase A2alpha expression by cortisol in human amnion fibroblasts

Cytosolic phospholipase A2alpha (cPLA(2alpha), now known as PLA2G4A) is the enzyme catalyzing the formation of the rate-limiting substrate, arachidonic acid, for prostaglandin (PG) synthesis. The increasing expression of PLA2G4A toward term gestation in human amnion fibroblasts is believed to be the crucial event in parturition. Human amnion fibroblasts produce cortisol, progesterone and express glucocorticoid receptor (GR), progesterone receptor A (PGRA) form at term. The roles of progesterone and PGRA in the induction of PLA2G4A by cortisol via GR in the amnion fibroblasts remain largely unknown. Using cultured human term amnion fibroblasts, we found that cortisol induced the expression of PGRA, which was attenuated by inhibiting PG synthesis with indomethacin. Knockdown of PGRA expression or inhibition of endogenous progesterone production with trilostane significantly enhanced the induction of PLA2G4A by cortisol, whereas overexpression of PGRA attenuated the induction of PLA2G4A by cortisol. Although exogenous progesterone did not alter PLA2G4A expression under basal conditions, it attenuated cortisol-induced PLA2G4A expression at concentrations about tenfold higher, which might be achieved by competition with cortisol for GR. In conclusion, PGRA in the presence of endogenous progesterone is a transdominant repressor of the induction of PLA2G4A by cortisol. High level of progesterone may compete with cortisol for GR, thus further inhibiting the induction of PLA2G4A by cortisol. Moreover, increased PG synthesis by cortisol may feed back on the expression of PGRA leading to attenuation of cortisol-induced PLA2G4A expression. The above findings may be pertinent to the inconsistent effects of glucocorticoids on parturition in humans.

Expression of progesterone receptor A form and its role in the interaction of progesterone with cortisol on cyclooxygenase-2 expression in amnionic fibroblasts

CONTEXT

Human amnion fibroblasts produce abundant prostaglandins toward the end of gestation, which is believed to be one of the major events leading to parturition. Glucocorticoids have been shown to up-regulate cyclooxygenase-2 (COX-2) expression, the crucial enzyme catalyzing prostaglandin synthesis, in human amnion fibroblasts. Although a major propregnancy hormone, the effect of progesterone and the associated progesterone receptor subtypes in the regulation of both basal and glucocorticoid-induced COX-2 expression in human amnion fibroblasts have not been resolved.

METHODS AND RESULTS

Cultured human amnion fibroblasts prepared from the fetal membranes at term pregnancy without labor mainly expressed the progesterone receptor A form (PRA). Inhibition of endogenous progesterone production with trilostane or knockdown of PRA expression with small interfering RNA significantly enhanced the glucocorticoid receptor (GR)-mediated COX-2 induction by cortisol, whereas overexpression of PRA attenuated the induction by cortisol. Co-immunoprecipitation assay revealed PRA in the GR protein complex. Although exogenous progesterone did not alter COX-2 expression under basal conditions, it attenuated cortisol-induced COX-2 expression at concentrations about 10- to 50-fold higher, which might be achieved by competition with cortisol for GR.

CONCLUSIONS

We demonstrated in this study that endogenous progesterone might counteract the induction of prostaglandin synthesis by cortisol via PRA transdominant repression of GR function, whereas high levels of progesterone might further inhibit the induction by cortisol via competitive binding to GR in human amnion fibroblasts. These inhibitory actions of progesterone and PRA on glucocorticoids and GR may partly explain the inconsistent effects of glucocorticoids on parturition in humans.

Effects of arecoline on testosterone release in rats

Arecoline is one of the major components of betel nuts, which have been consumed as chewing gum in Southeast Asia. In this study, the effects of arecoline on testosterone (T) secretion were explored. Male rats were injected with human chorionic gonadotropin (hCG, 5 IU/kg) or arecoline (1 microg/kg) plus hCG via a jugular catheter. Blood samples were collected at several time intervals subsequent to the challenge. Rat anterior pituitary was treated with gonadotropin-releasing hormone in vitro with or without arecoline, and then the concentrations of luteinizing hormone (LH) in the medium were measured. Rat Leydig cells were purified by Percoll density gradient centrifugation and incubated with arecoline, hCG, forskolin, 8-bromo-cAMP (8-Br-cAMP), nifedipine, nimodipine, or tetrandrine at 34 degrees C for 1 h. A single intravenous injection of arecoline resulted in an increase of the hCG-induced level of plasma T. Administration of arecoline (10(-8) to 10(-6) M) in vitro increased T production in Leydig cells. The stimulatory effect of arecoline on T release in vitro was enhanced by hCG (0.001 IU/ml), forskolin (10(-6) M), or 8-Br-cAMP (10(-5) M). By contrast, nifedipine, nimodipine, or tetrandrine inhibited the increased T concentrations induced by arecoline. Western blot showed that arecoline increases steroidogenic acute regulatory (StAR) protein expression compared with vehicle. These results suggested that arecoline stimulates testosterone production by acting directly on Leydig cells via mechanisms involving an activation of L-type calcium channels, increasing the activity of 17beta-hydroxysteroid dehydrogenase and enhancing the expression of StAR.

The Use of Trilostane for the Treatment of Alopecia X in Alaskan Malamutes

Three Alaskan malamutes with hair loss and slightly elevated blood concentrations of 17-hydroxyprogesterone after stimulation with adrenocorticotropic hormone (ACTH) were treated with trilostane. Trilostane, an inhibitor of 3 β-hydroxysteroid dehydrogenase, was given twice daily at a dose of 3.0 to 3.6 mg/kg per day orally for 4 to 6 months. Routine ACTH stimulation tests were performed over 8 months to evaluate the degree of adrenal function suppression. Treatment with trilostane led to complete hair regrowth in all three dogs within 6 months. No adverse effects associated with trilostane were recognized.

Labor induction abortion utilizing trilostane, a 3beta-hydroxysteroid dehydrogenase inhibitor

Labor induction abortion in the second trimester is a difficult problem in developing countries because antiprogestins are either not available or unaffordable. When prostaglandins are used alone for labor induction abortion without antiprogestin pretreatment, the induction to delivery interval and the treatment failure rate increase. Trilostane, an inhibitor of 3beta-hydroxysteroid dehydrogenase enzyme system, was given to 93 women between 13 and 19 weeks gestation. The trilostane dosage used was 120 mg twice daily for the first 24 h, and then 240 mg twice daily for the next 24 h. The women returned after 48 h for hospital admission. The women were randomized to three different misoprostol regimens: low-dose vaginal group (200 microg every 4 h), high-dose vaginal group (initial dose of 400 microg followed by 200 microg every 4 h) and vaginal-oral group (400 microg vaginally followed by 200 microg orally every 4 h). The median induction to abortion times were 17, 8.3 and 9.4 h, respectively. The latter two groups had significantly shorter induction to delivery times (p<.05). The most common side effects were a burning feeling in the face (47.7%) and nausea (13.3%). Overall, trilostane side effects were mild and self-limiting and did not interfere with therapy. In conclusion, trilostane can be given as out-patient therapy prior to admission for prostaglandin administration in labor induction abortion.

Treatment of canine Alopecia X with trilostane

Sixteen Pomeranians and eight miniature poodles presenting with clinical signs of alopecia X, elevated blood concentrations of 17-hydroxyprogesterone post stimulation with adrenocorticotropic hormone and increased urinary cortisol/creatinine ratios were treated with trilostane, a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. Trilostane was given once or twice daily at a mean dose of 10.85 mg kg(-1) day(-1). Adrenal function was evaluated with a follow-up of 28 months in the Pomeranians and 33 months in the miniature poodles. Treatment with trilostane led to complete hair re-growth in 85% of the Pomeranians and in all of the miniature poodles within 4 to 8 weeks. No adverse events attributed to treatment with trilostane were recognized. The hair re-growth might have been the result of a down-regulation of adrenal steroids and/or of the noncompetitive inhibition of the oestrogen receptors at the hair follicle level.