Activin A, activin receptor type II, nodal, and cripto mRNA are expressed by eutopic and ectopic endometrium in women with ovarian endometriosis.

Activin A is a dimeric protein that regulates endometrial functions by signaling at its receptors, namely type I (ActRI) and type II (ActRII). Nodal is an activin competitor that requires the coreceptor cripto to assemble its signaling pathway through ActRI and ActRII. In the current study, we evaluated the expression of activin A, ActRII, nodal, and cripto in eutopic and ectopic endometrium collected from women with ovarian endometrioma (n = 15) and in eutopic endometrium of healthy participants (n = 15). Eutopic endometrial samples were evaluated according to the stage of menstrual cycle. Total RNA was extracted from tissue homogenates and analyzed by real-time polymerase chain reaction (PCR). Activin A messenger RNA (mRNA) expression in eutopic endometrium of patients with endometriosis was significantly higher than in controls (P < .001) with a 10.2-fold and 7.3-fold increase in the proliferative and secretory phases, respectively. ActRII and nodal mRNA expression were found to be similar in patients with and without endometriosis, while cripto mRNA was markedly lower in eutopic (fold change = 0.03 at proliferative phase, P < .001) and ectopic endometrium (fold change = 0.14, P < .001) of women with endometriosis compared with eutopic endometrium from healthy controls. In conclusion, the altered endometrial expression of activin A and cripto during the menstrual cycle and the differences observed in the endometriotic tissue support the involvement of the activin system in endometrial changes of women with endometriosis.

Mechanistic and therapeutic implications of angiogenesis in endometriosis.

Like tumor metastases, endometriotic implants require neovascularization to proliferate and invade into ectopic sites within the host. Endometrial tissue, with its robust stem cell populations and remarkable regenerative capabilities, is a rich source of proangiogenic factors. Among the most potent and extensively studied of these proteins, vascular endothelial growth factor has emerged as a critical vasculogenic regulator in endometriosis. Accordingly, angiogenesis of the nascent endometriotic lesion has become an attractive target for novel medical therapeutics and strategies to inhibit vascular endothelial growth factor action. Vascular endothelial growth factor gene regulation in endometrial and endometriosis cells by nuclear receptors, other transcription factors, and also by infiltrating immune cells is emphasized. New data showing that oxidative and endoplasmic reticulum stress increase vascular endothelial growth factor expression are provided. Finally, we review the clinical implications of angiogenesis in this condition and propose potential antiangiogenic therapies that may become useful in the control or eradication of endometriotic lesions.

Plasma urocortin levels in the diagnosis of ovarian endometriosis.

OBJECTIVE: Urocortin is a neuropeptide, member of the corticotropin-releasing hormone family, that is produced by the human endometrium. Ovarian endometrioma is a prevalent gynecologic disorder still lacking specific serum markers. In the present study we measured systemic levels of urocortin to assess the diagnostic performance of its determination in distinguishing endometriomas from other benign ovarian cysts. METHODS: Plasma urocortin was measured by radioimmunoassay in women with ovarian endometrioma (n=40) and in women with benign, nonendometriotic ovarian cysts (n=40). The diagnostic accuracy of urocortin measurement was evaluated by receiver operating characteristic curve and compared with the standard marker, CA 125. To support the local origin of the peptide, we also evaluated its localization in endometriomas by immunohistochemistry and its concentrations in cyst fluid and peritoneal fluid of 12 women with endometrioma. RESULTS: Plasma urocortin levels were twice as high in women with endometrioma (median 49 pg/mL, interquartile range 41-63 pg/mL) than in the control group (19 [15-23] pg/mL, P<.001) and significantly higher in the cystic content of endometriomas than in the peritoneal fluid and plasma (P<.05). The peptide was immunolocalized in endometrioma glands and stromal capillary vessels. Elevated plasma urocortin levels detected 88% of the cases of endometrioma with 90% specificity, whereas CA 125 detected only 65% of the cases with the same specificity. CONCLUSION: Plasma urocortin is increased in women with endometriomas, and its measurement may be useful for the differential diagnosis of endometrioma compared with other benign ovarian cysts. LEVEL OF EVIDENCE: II.

Interleukin 1beta and progesterone stimulate activin a expression and secretion from cultured human endometrial stromal cells.

Steroid hormones, cytokines, and growth factors have a major role in evoking local endometrial changes needed for trophoblast implantation. In the present study, the effect of interleukin-1beta (IL-1beta), 17-beta estradiol (E2), and progesterone (Pr) on activin A and follistatin (FS) secretion from cultured human endometrial stromal cells (HESCs) is evaluated. HESCs were obtained from healthy human endometrial samples (n = 8) collected from healthy women. The cells were cultured and stimulated with E2 (10(-7) M, 10(-6)M), Pr (10(-7)M, 10(-6)M), IL-1beta (500 pg/mL), IL-1beta (500 pg/mL) + E2 (10(-6)M), and IL-1beta (500 pg/mL) + Pr (10(-6)M). Activin A and FS secretion and mRNA expression were assayed by enzyme-linked immunosorbent assay and semiquantitative reverse transcriptase-polymerase chain reaction, respectively. Pr (10(-7) M, 10(-6) M) significantly increased activin A secretion and mRNA expression from HESCs, but E2 did not show remarkable effects. The addition of IL-1beta (P< .001), IL- 1beta + E2 (P < .01), and IL-1beta + Pr (P< .001). significantly stimulated activin A secretion and mRNA expression, compared to untreated cells. Activin A expression and secretion after the coincubation of IL-1beta+ Pr were significantly higher than after IL-1betaand IL-1beta+ E2 stimuli ( P< .01 and P< .001, respectively). Neither Pr nor E2 and IL-1beta had a significant effect on FS secretion and expression. IL-1betaand Pr stimulated activin A but not FS secretion from cultured HESCs, and the effect of IL-1betawas augmented by Pr. These findings, together with the evidence that activin A is involved in trophoblast implantation, suggest the existence of a complex cross-talk by which the ovary, through Pr secretion, and the embryo, through IL-1beta production, may trigger the endometrial induction of activin A and consequently timing implantation.

Deranged expression of follistatin and follistatin-like protein in women with ovarian endometriosis.

OBJECTIVE: To evaluate the messenger RNA (mRNA) expression and peptide localization of follistatin and follistatin-like protein (FLRG) in ovarian endometriosis, compared to healthy human endometrium. DESIGN: Samples of ovarian endometriotic and healthy endometrial tissues were processed by semiquantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry. SETTING: Academic health centers in Siena, Italy, and Belo Horizonte, Brazil. PATIENT(S): Women with endometrioma who underwent laparoscopic excision of ovarian endometriotic cysts (n = 16), and healthy, nonpregnant women (n = 18, control group). MAIN OUTCOME MEASURE(S): Immunostaining and relative quantification of follistatin and FLRG mRNA in ovarian endometriosis and eutopic endometrium. RESULT(S): Both ovarian endometriosis and healthy endometrium expressed and localized follistatin and FLRG. In endometriotic glands, follistatin immunostaining was homogeneously distributed throughout the cytoplasm of the epithelial cells, contrasting with normal eutopic endometrium, where follistatin expression was focal, irregular, and confined to the basal side of the glands. Follistatin-like protein was immunolocalized in the nuclei of both glandular epithelial cells and stromal cells, with less intense staining in endometriotic samples. The relative intensity of follistatin and FLRG immunostaining was significantly higher and lower, respectively, in endometriosis than in controls. The expression of follistatin mRNA was higher, while that of FLRG mRNA was lower, in ovarian endometriosis than in healthy eutopic endometrium. CONCLUSION(S): Ovarian endometriotic lesions show a deranged expression of FLRG and follistatin, which are activin A-binding proteins. This may result in an altered effect of activin A on angiogenesis and/or endometrial differentiation.

Human endometrium expresses urocortin II and III messenger RNA and peptides.

Urocortin II and urocortin III are recently identified corticotropin-releasing factor-related neuropeptides, and their endometrial expression throughout the menstrual cycle and in early pregnancy was evaluated in the present study by semiquantitative reverse transcriptase polymerase chain reaction and immunohistochemistry. The endometrial expression of urocortin II mRNA was significantly (P<.01) higher in the early proliferative phase of the menstrual cycle than in other phases and maternal decidua (MD), whereas that of urocortin III mRNA was higher (P<.01) in MD than in all other endometrial samples. Both peptides were immunolocalized in epithelial, stromal, and endothelial cells.

Urocortin expression is downregulated in human endometrial carcinoma.

Urocortin (UCN) is a 40-amino acid neuropeptide sharing 45% sequence homology with corticotropin-releasing factor (CRF). The human endometrium expresses both UCN and CRF, and CRF/UCN receptors type-1 (CRF-R1) and -2 (CRF-R2). CRF-R1 activation inhibits cell growth and proliferation of a tumor cell line derived from the human endometrium, and the UCN signaling pathway has been implicated in tumorigenesis of several tissues. Therefore, we investigated whether UCN mRNA and peptide are expressed by human endometrial adenocarcinoma, and whether their expression changes compared to controls. Samples of well (grade 1; n = 6 endometrioid adenocarcinoma, of whom n = 1 with squamous differentiation, and n = 1 clear-cell carcinoma) and poorly differentiated (grade 3; n = 3 endometrioid adenocarcinoma) endometrial adenocarcinoma were collected from nine women (age range 61-79 years) enrolled at the time of diagnosis. Healthy endometrium was collected from postmenopausal women (controls; n = 13; age range 64-78 years), who underwent hysterectomy for uterine prolapse. Immunohistochemistry was used to evaluate cellular UCN localization, with the intensity of immunostaining scored on a subjective scale. Quantitative real-time reverse transcriptase (RT)-PCR analysis was used to estimate mRNA expression changes and restriction analysis was used to confirm PCR products identity. UCN mRNA expression was significantly reduced (P < 0.0001) in endometrial adenocarcinoma than in healthy controls. Immunoreactive UCN was found in luminal and glandular epithelial cells in healthy, but not in neoplastic samples. UCN mRNA and peptide expressions are decreased in endometrial adenocarcinoma. These data and the evidence that endometrial cancer expresses UCN receptors and UCN is involved in tumorigenesis of several tissues together suggest a role for UCN in endometrial tumoral cell growth and proliferation.

Urocortin 2 and urocortin 3 are expressed by the human placenta, deciduas, and fetal membranes.

OBJECTIVE: Urocortin 2 (UCN2) and urocortin 3 (UCN 3) are recently identified neuropeptides showing homology to corticotropin-releasing factor (CRF). In the present study, we evaluated their expression and localization in gestational tissues (placenta, decidua, fetal membranes), and their effect on placental adrenocorticotropic hormone secretion. STUDY DESIGN: The study was performed in a tertiary clinical care center. Tissues were obtained at first (n = 8; 8-11 weeks of pregnancy) and third (n = 8; 38-40 gestational weeks) trimester. The mRNA expression was evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR); the cellular localization by immunohistochemistry; ACTH levels were measured in media collected from cultured placental villi. RESULTS: All tissues analyzed expressed UCN2 and UCN3 mRNA. UCN2 and UCN3 were localized in cytotrophoblast and syncytiotrophoblast cells; UCN2 was present in maternal and fetal vessels and in amniotic cells, while UCN3 was absent. Finally, UCN2 and UCN3 did not stimulate ACTH secretion. CONCLUSION: Gestational tissues differentially express UCN2 and UCN3 and, despite their homology to CRF, they did not stimulate placental ACTH secretion.