Expression of adrenomedullin by human placental cytotrophoblasts and choriocarcinoma JAr cells

Adrenomedullin is a multifunctional peptide expressed in a variety of tissues. This study was conducted to investigate the expression of adrenomedullin and its mRNA by human trophoblasts and the possible existence of adrenomedullin receptor in those cells. Human placentas in all three trimesters were obtained from patients undergoing therapeutic abortions and deliveries. Total RNA was extracted from placental trophoblastic tissues and JAr choriocarcinoma cells, and the expression of adrenomedullin mRNA was determined by RT-PCR. Immunohistochemical analysis was performed by the avidin/biotin immunoperoxidase method using a specific antibody to adrenomedullin. The secretion of adrenomedullin by JAr cells cultured in medium containing [35S]cysteine-[35S]methionine was determined by immunoprecipitation followed by PAGE. The presence of adrenomedullin receptor in JAr cells was examined using a binding assay with [125I]rat adrenomedullin. Adrenomedullin mRNA was expressed by human placental trophoblastic tissues in all three trimesters and by JAr cells. Immunohistochemical analysis revealed that adrenomedullin is expressed by cytotrophoblasts in placentas in all three trimesters, but not by syncytiotrophoblasts. The expression of adrenomedullin in the cytotrophoblast was most abundant in first trimester placenta and became less abundant during the course of pregnancy. JAr cells synthesized and secreted immunoreactive adrenomedullin. Binding assay with [125I]rat adrenomedullin demonstrated specific binding of adrenomedullin to JAr cells, indicating the existence of a specific receptor for adrenomedullin in trophoblastic cells. Adrenomedullin is transcribed and secreted by cytotrophoblastic cells that possess adrenomedullin receptor. Adrenomedullin may play a potential role as an autocrine/paracrine factor in the growth of cytotrophoblasts, especially in early gestation.     

Gonadotropin-releasing hormone antagonist cetrorelix down-regulates proliferating cell nuclear antigen and epidermal growth factor expression and up-regulates apoptosis in association with enhanced poly(adenosine 5'-diphosphate-ribose) polymerase expression in cultured human leiomyoma cells

The objective of this study was to elucidate the effects of GnRH antagonist Cetrorelix on proliferation and apoptosis in human leiomyoma cells cultured in vitro. Isolated leiomyoma cells were subcultured in phenol red-free DMEM supplemented with 10% fetal bovine serum for 120 h and then stepped down to serum-free conditions in the presence or absence of graded concentrations of Cetrorelix (10(-5) to 10(-8) mol/liter) for 6 d. Cultured leiomyoma cells were used for semiquantitative RT-PCR, immunocytochemistry, Western blot analysis, and terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling assay. RT-PCR analysis revealed the presence of mRNAs encoding for GnRH receptor and epidermal growth factor (EGF) in cultured leiomyoma cells. The number of viable cultured leiomyoma cells was significantly (P < 0.01) decreased by treatment with Cetrorelix compared with untreated control cultures. Immunocytochemical examination demonstrated that treatment with Cetrorelix attenuated the expression of proliferating cell nuclear antigen (PCNA) and EGF in cultured leiomyoma cells. Western blot analysis revealed that treatment with 10(-5) mol/liter Cetrorelix significantly (P < 0.01) decreased PCNA expression. In addition, treatment with 10(-5) mol/liter Cetrorelix remarkably increased the terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling-positive rate and poly(ADP-ribose) polymerase expression at 24 h of treatment compared with untreated control cultures (P < 0.01). Furthermore, treatment with 10(-5) mol/liter Cetrorelix decreased immunoreactive EGF protein and EGF mRNA expression in cultured leiomyoma cells at 4 d of treatment. GnRH antagonist Cetrorelix may directly inhibit leiomyoma cell growth by down-regulating proliferation in association with a decrease in EGF mRNA expression and by up-regulating apoptosis in those cells.     

Estradiol/progesterone-releasing vaginal rings for hormone replacement therapy in postmenopausal women.

In order to investigate whether vaginal rings delivering estradiol and progesterone could prevent endometrial hyperplasia and relieve climacteric symptoms, two variants of rings were used in 20 postmenopausal women with intact uteri for 4 months. One ring designated as PI-002 (n = 8) delivered in vitro estradiol 160 microg/day and progesterone 20 mg/day, while the other (PI-003; n = 12) delivered the same dosage of estradiol but only half the progesterone (10 mg/day). Serum estrone, estradiol and progesterone were measured at pretreatment, weekly for 4 weeks, and then monthly for 4 months. The incidence of hot flushes, frequency of night sweats, mood scores, vaginal discharge and bleeding profiles were recorded. Endometrial thickness was monitored by ultrasonography. The mean estrone level was 50 pg/ml for 16 weeks. The mean serum estradiol level was 75 pg/ml for the first 4 weeks and gradually decreased to 50 pg/ml at 16 weeks. The mean progesterone level with the PI-002 ring was 5 ng/ml for the first 4 weeks and decreased to 3.5 ng/ml at 16 weeks. With the PI-003 ring, the mean progesterone level was initially 3.5 ng/ml and then decreased to 2.5 ng/ml thereafter. Significant decreases in the incidence of hot flushes and night sweats as well as a striking improvement in mood scores were noted as early as 2 weeks after insertion. Three of the 20 women discontinued the treatment, owing to ring expulsion. Increased vaginal discharge was observed with both rings in the first 6 weeks. Vaginal bleeding was more frequently apparent among users of the PI-002 ring, although bleeding and spotting were confined to the first 6 weeks. Ultrasonographic monitoring of the endometrium constantly revealed a thickness of < 3 mm for both variants throughout use for 16 weeks. An estradiol/progesterone-releasing vaginal ring is a potential alternative to long-term hormone replacement therapy with minimum attention required. It provides effective protection against endometrial hyperplasia.