Comparison of Estetrol Exposure between Women and Mice to Model Preclinical Experiments and Anticipate Human Treatment.

Estetrol (E4) is a natural estrogen with promising therapeutic applications in humans. The European Medicines Agency and the Food and Drug Administration have approved the use of 15 mg E4/3 mg drospirenone for contraceptive indication. Phase III clinical trials with 15-20 mg E4 for the relief of climacteric complaints are currently running. Relevant data from preclinical animal models are needed to characterize the molecular mechanisms and the pharmacological effects of E4 and possibly to reveal new therapeutic applications and to anticipate potential adverse effects. Therefore, it is important to design experimental procedures in rodents that closely mimic or anticipate human E4 exposure. In this study, we compared the effects of E4 exposure after acute or chronic administration in women and mice. Women who received chronic E4 treatment per os at a dose of 15 mg once daily reached a steady state within 6 to 8 days, with a mean plasma concentration of 3.20 ng/mL. Importantly, with subcutaneous, intraperitoneal or oral administration of E4 in mice, a stable concentration over time that would mimic human pharmacokinetics could not be achieved. The use of osmotic minipumps continuously releasing E4 for several weeks provided an exposure profile mimicking chronic oral administration in women. Measurements of the circulating concentration of E4 in mice revealed that the mouse equivalent dose necessary to mimic human treatment does not fit with the allometric prediction. In conclusion, this study highlights the importance of precise definition of the most appropriate dose and route of administration to utilize when developing predictive preclinical animal models to mimic or anticipate specific human treatment.

Use of liposome-encapsulated estetrol for treatment of neonatal hypoxic-ischemic encephalopathy.

Estetrol (E4) is a natural estrogen synthesized only during pregnancy. It has strong neuroprotective and antioxidative activities. The aim of the present study was to define the neuroprotective potency of E4 encapsulated either in liposome (Lipo-E4) or in drug-in cyclodextrin (HP-ß-CD) in liposome (DCL) system, and compare them with a single use of E4. In vitro studies were performed in an oxidative stress model of primary hippocampal neuronal cell cultures, followed by the lactate dehydrogenase activity and cell proliferation assays. In vivo studies were conducted by using a model of neonatal hypoxic-ischemic encephalopathy in immature rat pups. Brain samples were studied by (immuno)histochemistry for the detection of survived cells, expression of microtubule-associated protein-2, myelin basic protein, doublecortin and vascular-endothelial growth factor. Concentrations of glial fibrillary acidic protein in blood serum were studied by ELISA. In vitro, cell proliferation was significantly up-regulated in cultures treated either by DCL-E4 or E4 compared to the control cells, whereas DCL-E4 treated cells had significantly higher survival rate than the cells treated by E4 alone. Evaluation of brain samples showed that DCL-E4 and a high dose of E4 alone significantly preserve the grey and the white matter loses, and diminish GFAP expression in blood. Although DCL-E4 and E4 have similar effect on neurogenesis in the hippocampus and the cortex, DCL-E4 treatment significantly up-regulates angiogenesis in the hippocampus compared to a single use of E4. Present work reveals for the first time that liposome-encapsulated E4 might be a better alternative to a single use of E4.

Liposomes and drug-in-cyclodextrin-in-liposomes formulations encapsulating 17ß-estradiol: An innovative drug delivery system that prevents the activation of the membrane-initiated steroid signaling (MISS) of estrogen receptor α.

The encapsulation into liposomes of several types of molecules presents the advantages to protect the activity of these molecules and to target specific tissues. Nevertheless, a major obstacle remains the incomplete understanding of nano-bio interactions. Specifically, the impact that inclusion of drug into liposomes or of drug-in-cyclodextrin-in liposomes (DCL) could have on the molecular and cellular mechanism of drug action is largely unknown. As a proof of concept, we evaluated the impact of 17ß-estradiol (E2) included into liposomes or DCL on estrogen receptor (ER)α signaling pathways. Indeed, ERα relays the pleiotropic actions of E2 in physiology and pathophysiology through two major pathways: (1) the genomic/nuclear effects associated to the transcriptional activity of the ERα and (2) the rapid/nongenomic/membrane-initiated steroid signaling (MISS) effects related to the induction of fast signaling pathways occurring when ERα is anchored to the plasma membrane. We evidenced that the inclusion of E2 into liposomes (Lipo-E2) or into DCL (DCL-E2) prevented the activation of the rapid/nongenomic/extranuclear/MISS pathway of ERα, while the activation of the genomic/nuclear pathway was maintained. These results support that Lipo-E2 and DCL-E2 could be a useful tool to delineate the complex molecular mechanisms associated to ERα. In conclusion, this study supports the notion that inclusion of drugs into liposomes or DCL could modify some specific pathways of their molecular and cellular mechanisms of action. These results emphasized that attention should be paid to nano-bio interactions induced by the use of nanovectors in medicine.

Estrogen receptors and estetrol-dependent neuroprotective actions: a pilot study.

Estetrol (E4) has strong antioxidative, neurogenic and angiogenic effects in neural system resulting in the attenuation of neonatal hypoxic-ischemic encephalopathy. We aimed to define the role of estrogen receptors in E4-dependent actions in neuronal cell cultures and prove the promyelinating effect of E4. In vitro the antioxidative and cell survival/proliferating effects of E4 on H2O2-induced oxidative stress in primary hippocampal cell cultures were studied using different combinations of specific inhibitors for ERα (MPP dihydrochloride), ERß (PHTTP), GPR30 (G15) and palmytoilation (2-BR). LDH activity and cell survival assays were performed. In vivo the promyelinating role of different concentrations of E4 (1 mg/kg/day, 5 mg/kg/day, 10 mg/kg/day, 50 mg/kg/day) was investigated using the hypoxic-ischemic brain damage model in the 7-day-old immature rats before/after the induction of hypoxic-ischemic insult. Myelin basic protein (MBP) immunostaining was performed on brain coronal sections. Our results show that LDH activity is significantly upregulated in cell cultures where the E4's effect was completely blocked by concomitant treatment either with ERα and ERß inhibitors (MPP and PHTPP, respectively), or ERα and ERß inhibitors combined with 2-BR. Cell survival is significantly downregulated in cell cultures where the effect of E4 was blocked by ERß inhibitor (PHTTP) alone. The blockage of GRP30 receptor did affect neither LDH activity nor cell survival. MBP immunostaining is significantly upregulated in E4-pretreated groups at a concentration of 5 mg/kg/day and 50 mg/kg/day E4, whereas the MBP-positive area OD ratio is significantly increased in all the E4-treated groups. E4's antioxidative actions mostly depend on ERα and ERß, whereas neurogenesis and possibly promyelinating activities might be realized through ERß.

Use of estetrol with other steroids for attenuation of neonatal hypoxic-ischemic brain injury: to combine or not to combine?

Estetrol (E4), estradiol (E2) and progesterone (P4) have important antioxidative and neuroprotective effects in neuronal system. We aimed to study the consequence of combined steroid therapy in neonatal hypoxic-ischemic encephalopathy (HIE). In vitro the effect of E4 combined with other steroids on oxidative stress and the cell viability in primary hippocampal cultures was evaluated by lactate dehydrogenase and cell survival assays. In vivo neuroprotective and therapeutic efficacy of E4 combined with other steroids was studied in HIE model of immature rats. The rat pups rectal temperature, body and brain weights were evaluated.The hippocampus and the cortex were investigated by histo/immunohistochemistry: intact cell number counting, expressions of markers for early gray matter lose, neuro- and angiogenesis were studied. Glial fibrillary acidic protein was evaluated by ELISA in blood samples. In vitro E4 and combinations of high doses of E4 with P4 and/or E2 significantly diminished the LDH activity and upregulated the cell survival.In vivopretreatment or treatment by different combinations of E4 with other steroids had unalike effects on body and brain weight, neuro- and angiogenesis, and GFAP expression in blood. The combined use of E4 with other steroids has no benefit over the single use of E4.

Combined estrogenic and anti-estrogenic properties of estetrol on breast cancer may provide a safe therapeutic window for the treatment of menopausal symptoms.

Increased risk of breast cancer is a critical side effect associated with the use of a menopausal hormone therapy (MHT). Estetrol (E4) is a natural estrogen produced by the human fetal liver and is a promising compound for clinical use in MHT. However, its impact on breast cancer is controversial and poorly defined. In this preclinical study, we show that E4 acts as a weak estrogen by stimulating the growth of hormone-dependent breast cancer only at concentrations exceeding menopausal therapeutic needs. E4 presents also an antitumor activity by decreasing the strong proliferative effect of estradiol (E2). While estrogen receptor alpha (ERα) is the predominant receptor mediating its effects, the dual weak-estrogenic/anti-estrogenic feature of E4 results from differential signaling pathways activation. Both nuclear and rapid extra-nuclear signaling pathway are necessary for a complete estrogenic effect of E4. However, the antitumor action of E4 is not due to a capacity to antagonize E2-induced nuclear activity. Altogether, our results highlight that E4 has a limited impact on breast cancer and may offer a safe therapeutic window for the treatment of menopausal symptoms.

Estetrol attenuates neonatal hypoxic-ischemic brain injury.

Estetrol (E4) is a recently described natural estrogen with four hydroxyl-groups that is synthesized exclusively during pregnancy by the human fetal liver. It has important antioxidative activity. The aim of the present study was to define the importance of E4 in the attenuation of neonatal hypoxic-ischemic encephalopathy. Antioxidative effect of 650µM, 3.25mM and 6.5mM E4 on primary hippocampal cell cultures was studied before/after H202-induced oxidative stress. To examine oxidative stress and cell viability, lactate dehydrogenase activity and cell proliferation colorimetric assays were performed. To study the neuroprotective and therapeutic effects of E4 in vivo neonatal hypoxic-ischemic encephalopathy model of 7-day-old newborn rat pups was used. The neuroprotective and therapeutic effects of estetrol before/after hypoxic-ischemic insult was studied in 1mg/kg/day, 5mg/kg/day, 10mg/kg/day, 50mg/kg/day E4 pretreated/treated groups and compared with the sham and the vehicle treated groups. The body temperature of the rat pups was examined along with their body and brain weights. Brains were studied at the level of the hippocampus and cortex. Intact cell counting and expressions of microtubule-associated protein-2, doublecortin and vascular-endothelial growth factor were evaluated by histo- and immunohistochemistry. ELISAs were performed on blood samples to detect concentrations of S100B and glial fibrillary acidic protein as brain damage markers. This work reveals for the first time that E4 significantly decreases LDH activity and enhances cell proliferation in primary hippocampal neuronal cell cultures in vitro, and decreases the early gray matter loss and promotes neuro- and angiogenesis in vivo.

Effects of 4-hydroxy-2-nonenal, a major lipid peroxidation-derived aldehyde, and N-acetylcysteine on the cyclooxygenase-2 expression in human uterine myometrium.

BACKGROUND: Chorioamnionitis is one of the important causes of preterm labor. Preterm labor with chorioamnionitis is associated with oxidative stress. We reported that 4-hydroxy-2-nonenal (4-HNE), a major end product of oxidative fatty acid metabolism, is accumulated in the placenta with chorioamnionitis. The aim of this study was to confirm the effect of 4-HNE on cyclooxygenase-2 (COX-2) and prostaglandin (PG) induction in the uterine myometrial tissues. We also examined the effect of N-acetylcysteine (NAC) on 4-HNE-induced COX-2 expression. METHODS: Uterine myometrial tissues were obtained from 5 patients. One of them underwent elective cesarean section without labor, and 4 of them underwent hysterectomy because of placental previa or atonic bleeding. We stimulated the uterine myometrial tissues with 4-HNE. In addition, the tissues were pretreated with NAC before 4-HNE treatment. The expression of COX-2 mRNA was observed by real-time PCR. PGE2 and prostacyclin release into the supernatants of the tissue cultures was measured by ELISA. RESULTS: 4-HNE induced the COX-2 mRNA expression and PGE2 production in the uterine myometrial tissue culture in a dose-dependent and time-dependent manner. NAC inhibited 4-HNE-induced COX-2 expression. CONCLUSION: 4-HNE may play an important role in preterm labor. NAC might be protective against preterm labor under oxidative stress.

The effect of tumor-associated protein RCAS1 gene silencing on blood pressure and urinary protein excretion in pregnant mouse: a pilot study.

OBJECTIVE: The level of tumor-associated receptor-binding cancer antigen that is expressed on SiSo cells (RCAS1) is decreased significantly in preeclamptic pregnancies. We hypothesized that RCAS1 protein gene silencing might affect blood pressure and proteinuria in pregnant mice. STUDY DESIGN: On postcoital day 7.5, pregnant imprinting control region mice were subjected to the transfer of small interfering RNA (siRNA) against RCAS1 protein into the uterine cavity with the use of a hemagglutinating virus Japan envelope. Scramble siRNA was used as a negative control. Blood pressure and urine albumin/creatinine measurements were performed. The effect of the transferred siRNA was examined in uterine samples on postcoital day 8.5 with the use of Western blotting and immunohistochemistry analyses. RESULTS: In the RCAS1 siRNA group, blood pressure significantly raised on postcoital days 9.5, 10.5, 11.5, and 15.5, whereas urine albumin/creatinine ratio was significantly increased on postcoital day 9.5 CONCLUSION: Our results suggest the importance of RCAS1 protein in the pathophysiologic condition of preeclampsia.

Maternal blood serum and plasma human tumor-associated antigen RCAS1 during the course of uncomplicated pregnancies: a prospective study.

PROBLEM: we aimed to investigate the expression of the tumor-associated RCAS1 protein in maternal blood of uncomplicated pregnancies. METHOD OF STUDY: maternal blood was obtained from women with uncomplicated pregnancies (N = 43) at 11-13, 20-22, 32-34, 37-38 weeks of gestation, and immediately after delivery. Serum RCAS1 concentration was studied by ELISA, and plasma mRNA was subjected to real-time (RT)-PCR. RESULTS: serum RCAS1 protein concentration was significantly up-regulated at 11-13 and 20-22 weeks than that at 32-34 weeks and after delivery. RCAS1 mRNA level was significantly increased at 11-13 weeks than that at 37-38 weeks. A significant positive correlation was defined between RCAS1 serum concentration at 11-13 weeks and gestational age at delivery and that between plasma RCAS1 mRNA levels at 37-38 weeks and umbilical cord blood base excess. A significant negative correlation was found between RCAS1 serum concentration at 37-38 weeks and umbilical cord blood pH at delivery. CONCLUSIONS: RCAS1 protein might have importance in the development of uncomplicated pregnancies and for the prediction of pregnancy outcome.

Nicotine restores endothelial dysfunction caused by excess sFlt1 and sEng in an in vitro model of preeclamptic vascular endothelium: a possible therapeutic role of nicotinic acetylcholine receptor (nAChR) agonists for preeclampsia.

OBJECTIVE: In this study we tested the hypothesis that nicotine restores proangiogenic functions to endothelial cells pretreated with soluble fms-like tyrosine kinase 1 and/or soluble endoglin. STUDY DESIGN: Wound healing assay and tube formation assay were performed using human umbilical vein endothelial cells treated with nicotine (10(-9) to 10(-6) M), and with various combinations of soluble fms-like tyrosine kinase 1 (100 ng/mL), soluble endoglin (100 ng/mL), and nicotine (10(-7) M). Enzyme-linked immunosorbent assay was performed to measure vascular endothelial growth factor, placental growth factor, and transforming growth factor-beta1 concentrations in the conditioned media treated with nicotine (10(-9) to 10(-6) M). RESULTS: Nicotine significantly facilitated endothelial migration and tube formation. By contrast, soluble fms-like tyrosine kinase 1 and/or soluble endoglin suppressed these endothelial functions. Nicotine restored these soluble fms-like tyrosine kinase 1 and/or soluble endoglin-reduced endothelial functions. Placental growth factor, but not transforming growth factor-beta1, production was significantly stimulated by the presence of nicotine. Vascular endothelial growth factor was undetectable. CONCLUSION: Our results suggest a possible mechanism for the protective effects of cigarette smoking against preeclampsia, thus proposing a therapeutic potential of nicotine or other nicotinic acetylcholine receptor agonists for preeclampsia.

Nicotine suppresses interleukin-6 production from vascular endothelial cells: a possible therapeutic role of nicotine for preeclampsia.

Normal pregnancy is the controlled state of inflammation and this systemic inflammatory response is reported to be more intense in preeclampsia. The current study tested the hypothesis that maternal serum stimulates interleukin 6 (IL-6) production from endothelial cells and that nicotine inhibits these effects. Human umbilical vein endothelial cells (HUVECs) were incubated with or without 0.5% serum from healthy pregnant women at term (n = 5) and treated with or without nicotine (10(-9) to 10(-6) mol/L) in the presence of 0.5% serum. Cell survival was determined by colorimetric assay. Interleukin 6 concentration and nuclear transcription factor kappa B (NF-kB) activities were determined by enzyme-linked immunosorbent assay (ELISA)-based method. Interleukin 6 production by endothelial cells was significantly stimulated in the presence of maternal serum. Nicotine significantly preserved cell survival and suppressed IL-6 production from endothelial cells. Nicotine also significantly inhibited NF-kB activation in endothelial cells. Nicotine inhibited inflammatory reaction through NF-kB suppression in vitro model of maternal vascular endothelium, and this effect may be one of the explanations for the reduced risk of preeclampsia in smokers.

Temporal and spatial expression of tumor-associated antigen RCAS1 in pregnant mouse uterus.

PROBLEM: The tumor-associated antigen RCAS1 (receptor-binding cancer antigen expressed on SiSo cells) is considered to play a role in the inhibition of maternal immune response during pregnancy, and participates in the initiation of labor and placental detachment. The aim of our study was to investigate the expression of RCAS1 protein in the uteri of normal pregnant mice. METHOD: of study Uteri with fetuses were collected from pregnant ICR mice on days 1.5, 3.5, 5.5, 7.5, and 9.5 p.c., and uterine and placental tissues were obtained separately on days 11.5, 13.5, 15.5, and 17.5 p.c. Samples were examined using real-time (RT)-PCR, Western blotting, and immunohistochemical analyses. RESULTS: In normal pregnant mice, RCAS1 protein mRNA was significantly increased on day 7.5 p.c. Antigen localization was detected in the placenta, decidua, and fetus. CONCLUSION: The results of this study suggest the importance of day 7.5 p.c. for RCAS1 protein expression in connection with placentation as a possible target for future in vivo studies.

Relationship between human tumor-associated antigen RCAS1 and gestational diabetes mellitus.

PROBLEM: The human tumor-associated receptor-binding cancer antigen expressed on SiSo cells (RCAS1) is considered to play a role in the inhibition of the maternal immune response during pregnancy. The aim of our study was to investigate the expression of RCAS1 protein in the placenta and to compare its concentration in maternal and cord blood sera between normal pregnancies and pregnancies complicated by gestational diabetes mellitus (GDM). METHOD OF STUDY: Samples were obtained from women with GDM (n = 8), women with type 1 DM (n = 5), and healthy term controls (n = 27) after delivery. Placentas were studied by immunohistochemistry, and real-time polymerase chain reaction. For assessment of RCAS1 concentrations in maternal and cord blood sera, enzyme-linked immunosorbent assay was performed. RESULTS: The RCAS1 protein mRNA expression in the placentas of patients with GDM was significantly lower than that in the controls (P = 0.005). The maternal blood RCAS1 protein concentration of the GDM cases was also significantly lower than that in the controls (P = 0.0411), whereas the cord blood RCAS1 protein concentration was significantly higher in the GDM and type 1 DM groups than in the controls (P = 0.0311 and P = 0.0192, respectively). CONCLUSION: The present results suggest that RCAS1 protein might have an important role in the development of GDM.

Level of S100B protein expression in the amnion at various gestational ages in the third trimester of normal pregnancies.

BACKGROUND: S100B protein is a unique calcium-binding protein. Its biological role within the cell populations is not completely defined. Some pathological conditions that develop during pregnancy could affect S100B concentrations in the amniotic fluid, cord blood, and maternal serum. The aim of our study was to assess the correlation between S100B protein expression in the amnion, amniotic fluid and gestational age in the third trimester of uncomplicated pregnancies. METHODS: Amnion, amniotic fluid, maternal peripheral and umbilical cord blood samples were collected from healthy women who delivered at 31-36 weeks (n=17), 37-40 weeks (n=22), and 41-42 weeks (n=21). The expression of S100B in the amnion was assessed by immunohistochemistry and real-time (RT)-PCR, and its concentrations in amniotic fluid, maternal and cord blood sera were determined by ELISA. RESULTS: The S100B protein expression in the amnion and its concentrations in amniotic fluid, maternal and cord blood sera of patients in the third trimester were not significantly different at various gestational ages. CONCLUSIONS: The S100B protein expression in the amnion and the S100B protein concentrations in amniotic fluid, maternal and cord blood do not vary significantly in the third trimester of uncomplicated pregnancies.

Post-ischemic hypothermia reduced IL-18 expression and suppressed microglial activation in the immature brain.

Inflammation is an important factor for hypoxia-ischemia (HI) brain injury. Interleukin (IL)-18 is a proinflammatory cytokine which may be a contributor to injury in the immature brain after HI. To investigate the effects of post-HI hypothermia on IL-18 in the developing brain, 7-day-old rats were subjected to left carotid artery ligation followed by 8% oxygen for 60 min and divided into a hypothermia group (rectal temperature 32 degrees C for 24 h) and a normothermia group (36 degrees C for 24 h). The IL-18 mRNA was analyzed with real-time RT-PCR, and the protein level was analyzed by Western blot, and the location and source of IL-18 were assessed by immunohistochemistry. The significant increase of the IL-18 mRNA was observed in the ipsilateral hemispheres of the normothermia group at 24 h and 72 h after HI compared with controls, but the level in the ipsilateral hemispheres of the hypothermia group was significantly reduced at both time points, compared with the normothermia group, respectively. The IL-18 protein level in the ipsilateral hemispheres of the normothermia group significantly increased at 72 h after HI compared with controls, however, the protein level of the hypothermia group was significantly decreased, compared with the normothermia group. IL-18-positive cells were observed throughout the entire cortex, corpus callosum (CC) and striatum in the ipsilateral hemispheres of normothermia group at 72 h after HI, however, little positive cells were observed in the hypothermia group. Double labeling immunostaining found that most of the IL-18-positive cells were colocalized with lectin, which is a marker of microglia. The number of ameboid microglia (AM) in the normothermia group was significantly increased in cortex and CC, compared with the number in controls, but there were very few ramified microglia (RM) in these areas. In contrast, the number of AM in the hypothermia group was significantly decreased in cortex and CC, compared with the number in the normothermia group, and there were no significant differences in the number of AM and RM between the hypothermia group and controls. In conclusion, we found that IL-18 mRNA and the protein level were attenuated by post-HI hypothermia and that post-HI hypothermia may decrease microglia activation in the developing brain.