RESUMEN
STUDY QUESTION: Do both ulipristal acetate (UPA) and mifepristone inhibit embryo-endometrial attachment at concentrations corresponding to the emergency contraception (EC) dose? SUMMARY ANSWER: Both UPA and mifepristone at concentrations corresponding to the EC dose do not have an inhibitory effect on embryo implantation, although mifepristone at a higher concentration appeared to have such an effect. WHAT IS KNOWN ALREADY: Levonorgestrel is commonly used for EC, but it only acts through inhibition of ovulation. UPA and mifepristone have higher efficacy as EC compared to levonorgestrel; while there is some suggestion that mifepristone may interfere with implantation, whether UPA has post-ovulatory action in inhibiting implantation is yet to be confirmed. STUDY DESIGN, SIZE, DURATION: An in vitro experimental study using trophoblastic spheroids made from JAr cell line as the embryo surrogate, and the Ishikawa cell line and primary human endometrial cells cultured to monolayer as the endometrial surrogate. The primary endometrial cells were collected from nine volunteer women in the mid-luteal phase with consent. PARTICIPANTS/MATERIALS, SETTING, METHODS: The study was conducted in a university gynaecology unit. The JAr and Ishikawa cell lines (or primary endometrial cells) were treated with graded concentrations of UPA (0, 0.04, 0.4 and 4 µM) or mifepristone (0, 0.1, 1 and 10 µM) for 24 h. Embryo-endometrial attachment was studied using an in vitro JAr spheroid-endometrial co-culture model. Expressions of progesterone receptor, ß-catenin and glycogen synthase kinase 3 ß (GSK-3ß) were studied with real-time RT-PCR and Western blotting, respectively. MAIN RESULTS AND THE ROLE OF CHANCE: In the Ishikawa experiments, there was no significant difference in the JAr spheroid attachment rate after treatment with UPA at 0 (93.0%), 0.04 (93.6%), 0.4 (93.4%) and 4 (91.4%) µM concentrations (P > 0.05); the attachment rate was reduced after treatment with mifepristone only at 10 µM (79.8%, P < 0.0001) but not at 0.1 (92.1%) or 1.0 (95.2%) µM concentrations. In the primary endometrial cell experiments, again no significant difference was observed in the JAr spheroid attachment rate after treatment with UPA 4 µM (42.6%) compared to control (46.5%, P > 0.05). Both UPA and mifepristone could significantly up-regulate progesterone receptor expression. There was no significant alteration in expression of ß-catenin and GSK-3ß after treatment with UPA 4 µM or mifepristone 10 µM (P > 0.05). LIMITATIONS, REASONS FOR CAUTION: The co-culture model is only a surrogate which may not fully represent the complicated process of embryo implantation in vivo, although there is no existing perfect model for studying implantation in vitro which fully resembles the latter. WIDER IMPLICATIONS OF THE FINDINGS: The lack of inhibitory effect on embryo implantation by UPA and possibly mifepristone at concentrations corresponding to the EC dose is an important information for contraceptive counseling. STUDY FUNDING/COMPETING INTEREST(S): We had free supply of the UPA compound used in this study from Laboratoire HRA Pharma. This work was supported by a Seed Fund from the Centre of Reproduction, Development and Growth, Faculty of Medicine, The University of Hong Kong, Hong Kong.
Asunto(s)
Anticonceptivos/administración & dosificación , Implantación del Embrión/efectos de los fármacos , Mifepristona/administración & dosificación , Norpregnadienos/administración & dosificación , Adhesión Celular , Línea Celular , Proliferación Celular , Supervivencia Celular , Técnicas de Cocultivo , Anticoncepción Postcoital/métodos , Endometrio/efectos de los fármacos , Femenino , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Humanos , Transducción de Señal , Esferoides Celulares , beta Catenina/metabolismoRESUMEN
Feeding flaxseed to dairy cows can modulate gene expression and PG synthesis in the uterus at the time of peri-implantation. The objectives of the present study were to determine which flaxseed components are responsible for these effects and how different endometrial cell types are affected. We evaluated the effects of six different linoleic acid (n-6):α-linolenic acid (n-3) ratios and three concentrations of the lignan enterolactone (ENL) on endometrial stromal cells (SC) and epithelial cells (EC). The mRNA abundance of genes with known or suspected roles in embryo survival or PG synthesis was evaluated, along with PGE2 and PGF2α concentrations in culture media. The mRNA abundance of several genes was modulated by different fatty acid (FA) ratios and/or ENL, and this modulation differed between cell types. The FA4 (FA at an n-6:n-3 ratio of 4) treatment (rich in n-3 FA) increased the mRNA abundance of genes that have positive effects on uterine receptivity and implantation when compared with the FA25 (FA at an n-6:n-3 ratio of 25) treatment (rich in n-6 FA). ENL decreased PGE2 and PGF2α concentrations in both cell types, and this reduction was associated with lower mRNA abundance of the PG synthase genes AKR1B1 and PTGES in SC. The combination of ENL with FA (FA4 treatment) resulted in the greatest reduction in PGF2α concentrations when compared with the addition of FA (FA4) or ENL alone. Because of the known luteolytic properties of PGF2α, a reduction in endometrial PGF2α secretion would favour the establishment and maintenance of pregnancy.