Expression of estrogen and progesterone receptors and their mRNAs in ovarian endometriosis

Prolactin and Hyperprolactinaemia in Endometriosis-Related Infertility: Are There Clinically Significant Connections?

Endometriosis and hyperprolactinaemia are conditions that might lead to infertility as a consequence. The aim of this article was to present the current knowledge about possible relationships between prolactin/hyperprolactinaemia and endometriosis-related infertility. Experimental studies on local prolactin acting as cytokine and relationship of prolactin and endometriotic tissue, as well as clinical studies on hyperprolactinaemia and endometriosis-related infertility suggest the possible role of prolactin in endometriosis-related infertility, but final proof is still missing and the exact pathogenesis of infertility in such cases is still under investigation. Novel strategies in the treatment of endometriosis-related infertility, based on its connection with prolactin such as the use of prolactin receptor antibodies and prolactin receptor antagonists, are under investigation, but adequate clinical studies have yet to be undertaken.

Two Unsuccessful Clinical Trials on Endometriosis and a Few Lessons Learned

In 1999, a phase II clinical trial on the use of fulvestrant to treat endometriosis was launched; yet after 7 years there is still no report on its outcome. In 2005, another trial on the use of raloxifene to treat endometriosis was terminated early due to unfavorable outcome. The two apparently unsuccessful clinical trials on endometriosis have taught us a few important lessons. First, we need to understand endometriosis through more basic research. We have also been reminded that human endometriosis trials differ from animal studies; anatomy and physiology are often divergent, and outcome measures are certainly different. Ectopic endometrium can differ significantly from eutopic tissue, and this issue needs to be more thoroughly explored. We believe human cell lines will prove to be an inexpensive and valuable tool for future preliminary evaluation of medical therapies as well as discerning pathophysiologic processes of the disease. Based on our current understanding of endometriosis, some concrete benchmarks can be established for testing or screening potential compounds in vitro. Finally, estrogen receptor modulators are often tissue-, cell-, and context-specific in their actions; they should not be simplistically grouped together nor should extrapolations from one compound to another be undertaken in a cavalier manner.

Expression of matrix metalloproteinases in ovarian endometriomas: immunohistochemical study and enzyme immunoassay

Like carcinoma, endometriosis has the unique characteristics, of invasion and metastasis, though pathologically, it is a benign tumor. However, the mechanism of destruction of the surrounding tissue in endometriosis is still unclear. In this study, the expression and localization of matrix metalloproteinases (MMP)-1, -2, -3, -7, -9 and tissue inhibitors of metalloproteinases-1 (TIMP-1) were evaluated by immunohistochemistry for 20 cases and the amounts of MMP-1, TIMP-1 and MMP-1/TIMP-1 complex in the fluid of endometrioma, were analyzed by ELISA and western blotting for 20 cases, which were analyzed by immunohistochemical study. MMP-1, -2 and -9 were detected strongly in both stromal and epithelial cells and MMP-7 in the epithelial cells in the menstrual period. MMP-3 was mainly expressed in macrophage containing hemosiderin but the change of expression was not clear. TIMP-1 was intensively detected in both stromal and epithelial cells in the menstrual period but the expression decreased in other stages of the menstrual cycle. ELISA for MMP-1 also showed results similar to immunohistochemistry, suggesting that it was released to the cyst in the menstrual period when it was released to the extracellular space from the cytoplasm. The expression of TIMP-1 was not clearly changed during the menstrual cycle. From these results, it was suggested that the destruction of the surrounding matrix by endometriosis might be caused by various MMPs, which are mainly produced in stromal cells.

Prolactin receptor in human endometriotic tissues

BACKGROUND

Augmented serum prolactin (PRL) levels have been implicated as a cause for infertility in patients with endometriosis. However, it has not been established whether this lactogenic hormone or its receptor (PRLR) have specific effects on the development of human endometriosis. In the present study we assessed PRLR expression in human endometriotic and normal tissue.

METHODS

Fourteen patients with laparoscopically proven endometriosis were recruited and the negative or positive expression of the PRLR in normal endometrial and endometriotic tissues obtained during the mid-late proliferative phase of the menstrual cycle was evaluated by RT-PCR. Evaluation of serum prolactin, and peritoneal fluid estradiol content were carried out by specific radioimmunoassays (RIA).

RESULTS

In endometriotic tissue samples the corresponding 1048 bp PRLR transcript was negative in 12/14 of the samples (86%) and positive in two samples (14%). The opposite was seen in normal tissue, since PRLR expression was positive in 11/14 samples (79%) and negative in the remaining three samples (21%). There was an association between serum prolactin concentrations and PRLR expression in normal tissue but not in endometriotic tissue.

CONCLUSIONS

The PRLR is expressed in normal endometrium, while cells of the endometriotic tissues did not express the PRLR, at least during the mid-late proliferative phase of the menstrual cycle. The absence of the PRLR in the endometriotic tissues could not be correlated with the serum prolactin levels. These results suggest the existence of differential regulation of PRLR expression between normal and endometriotic tissue.