Inhibition of steroid sulfatase decreases endometriosis in an in vivo murine model.

BACKGROUND: Steroid sulfatase (STS) is involved in estrogen biosynthesis and expressed in eutopic and ectopic endometrium of disease-free and endometriosis patients. The present study was designed to investigate its role in endometriosis development. METHODS: Human endometrial explants were cultured on inserts for 24 h to assess the effectiveness of an STS inhibitor (STS-I), estradiol-3-O-sulfamate (E2MATE), on STS activity in endometrial tissue. Endometriosis was induced in mice, and E2MATE (or vehicle alone) was given orally for 21 days. Plasma estradiol levels were measured, and STS activity was assessed in murine organs (uterus, liver and leukocytes) and in lesions. Lesion number, weight and size (morphometry) were quantified. Lesion STS and progesterone receptor (PR) expression, proliferation and apoptosis rates were determined by immunohistochemistry. RESULTS: In vitro, addition of 1 µM E2MATE to the culture medium resulted in decreased STS activity in endometrial explants (P < 0.001). Treatment of mice with E2MATE (1.0 and 0.5 mg/kg) did not modify plasma estradiol levels, but inhibited STS activity in murine uterus (P < 0.05), liver (P < 0.001) and leukocytes (P < 0.001), as well as in induced lesions (P < 0.05). E2MATE reduced lesion weight (P < 0.01) and size (P < 0.05), but had no impact on proliferation or apoptosis rates, nor STS protein expression. Stromal edema was observed in the uterus of animals treated with E2MATE, but not in the stroma of lesions. Increased PR expression was detected in endometriotic lesions (P < 0.001). CONCLUSIONS: E2MATE was shown to effectively inhibit STS activity in endometrial tissue in vitro. In vivo, E2MATE decreased endometriosis development without affecting systemic estradiol levels. Use of STS-I could therefore be of potential interest in endometriosis treatment.

Expression of eicosanoid biosynthetic and catabolic enzymes in peritoneal endometriosis.

BACKGROUND: Increased peritoneal eicosanoid concentrations have been reported in endometriosis patients and might be important in disease-associated pain and inflammation. Here, we evaluated the expression of key biosynthetic and catabolic enzymes involved in this abnormal eicosanoid production in peritoneal macrophages and endometriotic lesions. METHODS: Peritoneal macrophages, endometriotic lesions and matched eutopic endometrium were collected from endometriosis patients (n = 40). Peritoneal macrophages and eutopic endometrium samples were also collected from disease-free women (n = 25). Expression of type IIA secretory phospholipase A(2) (sPLA(2)-IIA), cyclooxygenase-2 (COX-2), microsomal prostaglandin E synthase-1 (mPGES-1), 15-hydroxyprostaglandin dehydrogenase (15-PGDH) and 5-lipoxygenase (5-LO) was quantified by real-time PCR, and these five key enzymes were localized by immunohistochemistry. RESULTS: sPLA(2)-IIA, COX-2 and mPGES-1 mRNA was significantly increased in peritoneal macrophages of endometriosis patients compared with controls (P = 0.006, P = 0.016 and P = 0.025, respectively). In endometriosis patients, sPLA(2)-IIA, mPGES-1 and 15-PGDH mRNA was significantly enhanced in peritoneal lesions compared with matched eutopic endometrium (P < 0.001, P < 0.001 and P = 0.005, respectively). In eutopic endometrium, a significant decrease in 15-PGDH mRNA was found in the endometriosis group compared with controls (P = 0.023). Finally, sPLA(2)-IIA, COX-2, mPGES-1 and 15-PGDH immunostaining was found mainly in endometrial glands, whereas 5-LO was distributed throughout the glands and stroma. CONCLUSIONS: Our study highlights an imbalance between eicosanoid biosynthesis and degradation in endometriosis patients. Both peritoneal macrophages and endometriotic lesions may be involved. Research into new molecules inhibiting biosynthetic enzymes (such as sPLA(2)-IIA and mPGES-1) and/or activating catabolic enzymes (such as 15-PGDH) may prove to be a major field of investigation in the development of targeted medical therapies.

Absence of aromatase protein and mRNA expression in endometriosis.

BACKGROUND: Aromatase has been reported to be involved in estrogen biosynthesis and expressed in eutopic and ectopic endometrium of endometriosis patients. The objective of the present study was to investigate its expression and localization in three distinct types of endometriosis. METHODS: Human peritoneal, ovarian and rectovaginal endometriotic lesions and matched eutopic endometrium were collected from patients during laparoscopy. Aromatase protein localization (immunohistochemistry, n = 63) and mRNA expression [quantitative polymerase chain reaction (Q-PCR), n = 64] were assessed. RESULTS: No aromatase protein was detected by immunohistochemistry in either the glandular or stromal compartment of endometriotic lesions or eutopic endometrium, while it was strong in placental syncytiotrophoblasts, granulosa and internal theca cells from pre-ovulatory follicles, and luteal cells from corpus luteum. By Q-PCR, low but discernible levels of aromatase expression were found in endometriomas, probably due to follicular expression. Transcripts for aromatase were barely detectable in only a few peritoneal and rectovaginal endometriotic lesions, and a few eutopic endometrium samples, probably due to contaminating surrounding tissues (adipose tissue, intact peritoneum). CONCLUSIONS: Unlike previous studies, we observed no aromatase protein in any of the endometriosis types, and barely detectable aromatase mRNA expression, suggesting that locally produced aromatase (within endometriotic lesions) may be less implicated in endometriosis development than previously postulated. Potential factors responsible for these discrepancies are discussed.

Effects of selective oestrogen receptor modulators on proliferation in tissue cultures of pre- and postmenopausal human endometrium.

We characterised the effects of selective oestrogen receptor modulators (SERM) in explant cultures of human endometrium tissue. Endometrium tissues were cultured for 24h in Millicell-CM culture inserts in serum-free medium in the presence of vehicle, 17beta-estradiol (17beta-E2, 1nM), oestrogen receptor (ER) antagonist ICI 164.384 (40nM), and 4-OH-tamoxifen (40nM), raloxifene (4nM), lasofoxifene (4nM) and acolbifene (4nM). Protein expression of ERalpha, ERbeta1 and Ki-67 were evaluated by immunohistochemistry (IHC). The proliferative fraction was assessed by counting the number of Ki-67 positive cells. Nuclear staining of ER( and ER(1 was observed in the glandular epithelium and stroma of pre- and postmenopausal endometrium. ER(1 protein was also localized in the endothelial cells of blood vessels. Treating premenopausal endometrium tissue with 17beta-E2 increased the fraction of Ki-67 positive cells (p<0.001) by 55% in glands compared to the control. Raloxifene (4nM) increased (p<0.05) the Ki-67 positive fraction. All other SERMS did not affect proliferation in this model. Treating postmenopausal endometrium with 17(-E2 increased (p<0.001) the fraction of Ki-67 positive cells by 250% in glands compared to the control. A similar effect was also seen for 4-OH-tamoxifen, whereas the rest of SERMs did not stimulate proliferation. We demonstrated that oestradiol increases the fraction of proliferating cells in short term explant cultures of postmenopausal endometrium. In addition, we were able to reveal the agonistic properties of 4-OH-tamoxifen and confirm that raloxifene and next-generation SERMs acolbifene and lasofoxifene were neutral on the human postmenopausal endometrium.

Non-gestational malignant placental site trophoblastic tumor of the ovary in a 4-year-old rhesus monkey.

We report a case of ovarian malignant intermediate-type trophoblastic tumor in a clinically normal, nonpregnant 4-year-old rhesus monkey (Macaca mulatta). A large solid lobulated mass replaced the right ovary and filled the pelvis. Multiple metastases were observed within the lungs and the liver. The tumor was histologically identified as predominantly composed of intermediate trophoblastic cells, without prominent hemorrhages and the classic bilaminar pattern of cyto- and syncytiotrophoblastic cells characteristic of choriocarcinoma. Immunohistochemical analysis showed the presence of placental lactogen hormone in many tumor cells and chorionic gonadotropin in a few multinucleated cells consistent with syncytiotrophoblastic differentiation. No other germ cell differentiation was identified in the pelvis mass nor in the metastases. In the absence of previous and present pregnancy, this neoplasm has to be considered as a nongestational malignant placental site trophoblastic tumor of the ovary.

Potential involvement of iron in the pathogenesis of peritoneal endometriosis.

The aim of this study is to review the current literature associating endometriosis with iron and to discuss the potential causes and consequences of iron overload in the pelvic cavity. Indeed, iron is essential for all living organisms. However, excess iron can result in toxicity and is associated with pathological disorders. In endometriosis patients, iron overload has been demonstrated in the different components of the peritoneal cavity (peritoneal fluid, endometriotic lesions, peritoneum and macrophages). Animal models allow us to gather essential information on the origin, metabolism and effect of iron overload in endometriosis, which may originate from erythrocytes carried into the pelvic cavity mainly by retrograde menstruation. Peritoneal macrophages play an important role in the degradation of these erythrocytes and in subsequent peritoneal iron metabolism. Iron overload could affect a wide range of mechanisms involved in endometriosis development, such as oxidative stress or lesion proliferation. In conclusion, excess iron accumulation can result in toxicity and may be one of the factors contributing to the development of endometriosis. Treatment with an iron chelator could thus be beneficial in endometriosis patients to prevent iron overload in the pelvic cavity, thereby diminishing its deleterious effect.