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Objective: To compare the effects of chlormadinone acetate (CMA), dienogest (DNG) and drospirenone (DRSP) on prostaglandin biosynthesis in a human endometrial explants model., Study Design: Human endometrial explants obtained by aspiration curettage and human endometrial YHES cells were stimulated with interleukin-1β (IL-1β) and exposed to CMA, DNG, DRSP or dexamethasone (DEX; YHES cells). Cellular messenger RNA (mRNA) levels of cyclooxygenase-2 (COX-2) were analyzed by reverse-transcription quantitative real-time polymerase chain reaction. Concentrations of prostaglandin F 2α (PGF 2α ) in culture supernatants were measured by enzyme-linked immunosorbent assay., Results: CMA exerted after IL-1β stimulation a stronger down-regulation of COX-2 mRNA compared to DNG and DRSP in human explants (-55% vs. -40% and 46%, respectively). The effect of CMA on COX-2 mRNA was significantly stronger (p=.025) than that of DNG. Moreover, the effect of CMA was independent from cycle phase or presence of endometriosis. In order to evaluate the impact of the investigated progestins on effector molecules, PGF 2α release was determined in supernatants. Again, CMA reduced the PGF 2α release significantly by an average of -60% (p<.01). In contrast, no significant reduction was found for DNG and DRSP. In YHES cells, only DEX but not the progestins under study exerted a significant down-regulating effect (-79%, p<.01) on COX-2 mRNA after IL-1β stimulation., Conclusion: Among the tested progestins, CMA displayed the most consistent suppression of prostaglandin biosynthesis in human endometrial explants., Implication: Among three tested progestins, chlormadinone acetate had the most consistent suppressive effect on prostaglandins in endometrial explants. These findings support clinical observations about the efficacy of chlormadinone acetate in dysmenorrhea treatment., (Copyright © 2018. Published by Elsevier Inc.)

Scope: Indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM) from Brassica plants are regarded as promising anticancer phytochemicals. The enzyme telomerase is a very attractive target for cancer therapeutics; in normal cells such as lymphocytes, it plays a decisive role for cell maintenance. The effect of I3C and DIM on telomerase in normal human immune cells (PBMC) was studied compared to leukaemia cells (HL-60). Signalling of telomerase regulation via estrogen receptor (ER) was addressed., Methods and Results: Short-term treatment with I3C and DIM inhibited telomerase activity in leukaemia cells (>30 μM I3C; >3 μM DIM). In CD3/CD28 activated PBMC, inhibition was stronger, though (>3 μM I3C; >1 μM DIM). DIM long-term treatment resulted in DNA damage induction and proliferation inhibition in PBMC as determined by the comet assay and CFSE staining, respectively. A relevance of ERα/β-AP1 signaling for telomerase inhibition on enzyme activity, but not transcription level became evident indicating a nonclassical mode for ER regulation of telomerase by DIM., Conclusion: Although desired in cancer cells, this study identified a potential adverse impact of I3C and DIM on telomerase action in normal human immune cells, partly mediated by an ER-dependent mechanism. These new findings should be considered for potential chronic high-dose chemoprevention strategies using these compounds., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: To elucidate the mode of action of chlormadinone acetate (CMA) in reducing dysmenorrheic pain by studying the effects of CMA and dexamethasone (DEX) on messenger RNA (mRNA) abundance of cyclo-oxygenase-2 (COX-2), annexin-1 (ANXA1), glucocorticoid receptor (GR), progesterone receptor (PR), and concentrations of prostaglandin F(2α) (PGF(2α)) and leukotrienes B(4) (LTB(4)) and C(4) (LTC(4)) in human endometrial explants., Design: Ex vivo study., Setting: University hospital., Patient(s): Fifteen premenopausal patients undergoing surgery for benign gynecologic disorders., Intervention(s): Endometrial explants were obtained by aspiration curettage and stimulated ex vivo with interleukin-1β before exposure to CMA or DEX; mRNA levels were determined via reverse transcription-quantitative real-time polymerase chain reaction, and concentrations of arachidonic acid metabolites by enzyme immunoassays., Main Outcome Measure(s): Messenger RNA levels of COX-2, ANXA1, PR, and GR; concentrations of PGF(2α), LTB(4), and LTC(4) in endometrial explants treated with CMA or DEX., Result(s): In IL-1β-treated explants COX-2 mRNA and PGF(2α), concentrations were significantly down-regulated by CMA but not by DEX. Chlormadinone acetate did not affect mRNA abundance of ANXA1, PR, and GR., Conclusion(s): Our data suggest that CMA is a suppressor of COX-2 expression. Comparison with DEX revealed that progestin-specific activity of CMA may mainly be responsible for suppression of prostaglandin biosynthesis in human endometrium., (Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

The human endometrium is unique among adult tissues. Its functions are modulated by numerous hormones and mediators. The aim of this study was to evaluate the suitability of human endometrial explants for studying functional effects of chemicals and drugs on gene expression biomarkers. Endometrial tissues were obtained by aspiration curettage and cultivated for up to 24 h. Relative mRNA concentrations were determined by reverse transcription quantitative real-time PCR. Viability was assessed by light microscopy, lactate dehydrogenase assay and scanning electron microscopy. It was acceptable after 6 h of culture but reduced after 24 h. Culture-induced alterations of mRNA levels were found for progesterone receptor, estrogen receptor(α), leukemia inhibitory factor and cyclooxygenase-2 in tissues from all cycle stages. The suitability of the model to detect chemical effects was demonstrated by the down-regulation of cyclooxygenase-2 mRNA by chlormadinone acetate in proliferative and secretory endometrium. The model is mainly restricted by interindividual variations and varying tissue quality. An advantage is the preservation of tissue composition. We conclude that human endometrial explants are a complex model due to limited viability, difficult standardization and intrinsic alterations during culture. Experiments with this model should be performed over a limited time period under strictly controlled conditions.

ReProTect is a project within the 6th European Framework Program which has developed alternative methods aimed to reduce or replace animal experimentation in the field of reproductive toxicology. In its final year, a ring trial, named the "Feasibility Study", was conducted, in which 10 blinded chemicals with toxicologically well-documented profiles were analyzed by employing a test battery of 14 in vitro assays. EC(50) (half maximal effective concentration) or equivalent endpoints were determined and the test compounds were ranked relative to chemicals previously assayed in the tests of the battery. This comparative analysis together with a weight of evidence approach allowed a robust prediction of adverse effects on fertility and embryonic development of the 10 test chemicals in vivo. In summary, the vast majority of the predictions made based on the in vitro results turned out to be correct when compared to the whole animal data. The procedure used here, a nearest neighbor analysis coupled with a weight of evidence approach, may guide future activities in the field of alternative toxicity testing., (Copyright 2010 Elsevier Inc. All rights reserved.)

Recent research suggests a significant role for placental corticotropin-releasing hormone (CRH) in controlling human parturition. This paper describes the expression of CRH, CRH receptors 1 and 2, and CRH binding protein (CRH-BP) in gestational tissue in late pregnancy. Placenta, myometrium, decidua, and fetal membranes were collected after uncomplicated pregnancies at term caesarian section before the onset of labour. The localisation and mRNA expression of CRH, CRH receptors, and CRH-BP were studied by immunohistochemistry and reverse transcription (RT)-PCR. CRH receptors were detected in placenta, myometrium, decidua, and fetal membranes. We demonstrated for the first time the presence of CRH receptors on resident macrophages and on endothelial cells. CRH receptor 1 mRNA was detected in all tissues investigated by RT-PCR, whereas CRH receptor 2 mRNA was restricted to myometrium and decidua. CRH mRNA was widely expressed in all tissue under study. Novel findings are also presented on the expression of CRH-BP in the myometrium. This widespread expression of the CRH system in gestational tissue suggests a paracrine role for CRH in the birth process (e.g. effects on macrophages and endothelial cells).

Nitric oxide (NO) is a potent relaxant of smooth muscle and possibly plays a role in maintaining uterine quiescence during pregnancy. Clinical studies have shown beneficial effects of the stable NO donor glyceryl trinitrate (GTN) for the inhibition of pathological myometrial contractility that occurs in preterm labor or dysmenorrhea. Since there are contradictory results regarding the mediation of the relaxing effect of NO, the myometrial prostaglandin synthesis during superfusion with NO donors was studied. Human myometrial strips obtained either at term Cesarean sections before the onset of labor or after hysterectomies in premenopausal women were studied in a superfusion system. After the manifestation of spontaneous contractions, GTN was added in low doses comparable with in vivo levels (0.4-40 nM) and the effect on myometrial activity, intracellular cGMP and prostaglandin production was analyzed. Additionally, the effect of sodium nitroprusside (SNP)--which releases NO spontaneously--was compared with that of GTN. GTN caused a significant decrease in the contraction frequency of myometrial strips from both pregnant and non-pregnant women similar to that of SNP. There was no significant change in the myometrial synthesis of PGI2, PGF2 alpha and PGE2, whereas the intracellular cGMP content was increased. In conclusion, GTN showed a significant inhibitory effect on human myometrium in vitro in very low doses and therefore represents an interesting therapeutic alternative for the treatment of preterm labor and dysmenorrhea. GTN in low doses did not alter the prostaglandin synthesis of human myometrium.

Human term myometrium is poorly characterized as a source of proinflammatory mediators involved in parturition. We have investigated the basal expression of cytokines in myometrium, as well as the effects of CRH and lipopolysaccharide (LPS) on cytokine release. Explants from term myometrium were challenged with CRH or LPS (1 microg/mL each) in short-term tissue culture. Interleukin (IL)-1beta++, IL-6, IL-8, and tumor necrosis factor (TNF)alpha concentrations in the medium were quantified by enzyme immunoassay. The major cytokines released after 24 h were IL-6 and IL-8. All cytokines investigated were stimulated significantly by LPS (P: < 0. 05) but not by CRH. Messenger RNA levels of these cytokines were investigated by RT-PCR. IL-1beta+ and IL-6 messenger RNA were present in preterm and term myometrium before and during labor, whereas IL-8 and TNFalpha were expressed only by myometrium in active labor. Furthermore, myometrial CRH receptors and macrophages were characterized immunohistochemically. We conclude that human term myometrium is a site of production of proinflammatory cytokines and is involved in the inflammation-like reactions mediating the birth process. Cytokine release in term myometrium seems not to be under control of CRH.

Eicosanoids play a key role in pregnancy maintenance and parturition. We investigated the metabolism of arachidonic acid (AA) in short-term tissue cultures of placenta, fetal membranes, decidua and myometrium. Tissues were obtained from caesarean sections before the onset of labour after uncomplicated pregnancies. The released metabolites were analysed by high performance liquid chromatography (HPLC) and specific immunoassays. In radiotracer experiments tissues were labelled with [3H]-AA and metabolites released after incubation with calcium ionophore A23187 were profiled by HPLC. Decidua was more active in metabolizing AA (turnover 34 per cent) than myometrium (28 per cent), placenta (21 per cent) and fetal membranes (17 per cent). Main product in placenta, decidua and myometrium was 12-hydroxyeicosatetraeinoic (12-HETE) (decidua: 19 per cent of released radioactivity, myometrium 14 per cent, placenta 7 per cent). Fetal membranes formed 5-HETE as main product. Another major metabolite in placenta, fetal membranes and decidua was characterized by HPLC as 5(6)-epoxyeicosatrienoic acid. Only myometrium released appreciable amounts of prostaglandins in form of 6-keto-prostaglandin F1 alpha. In non-radioactive experiments formation of eicosanoids from endogenous AA was investigated by HPLC (fluorescence- and UV-detection) and immunoassays. These experiments confirmed the high production of 12-HETE and the low formation of prostaglandins. Our results suggest that the biological role of AA-metabolites, other than prostaglandins, have as yet been underestimated.