Involvement of estrogen receptor-related receptors in human ovarian endometriosis

Abstract

Objective: To determine whether decreased estrogen receptor alpha (ER-α) expression in endometriotic lesions could be balanced by an increased expression of estrogen receptor-related receptors (ERRs). To evaluate whether ERR-α expression is influenced by hormonal change in fertile and menopausal women.

Design: Prospective controlled study.

Setting: University Hospital, Department of Gynecology.

Patient(s): Twenty-five women: 20 women of reproductive age with (n = 10) and without (control; n = 10) endometriosis and 5 menopausal women.

Intervention(s): Real-time polymerase chain reaction (qPCR). Immunohistochemistry.

Main outcome measure(s): The ER and ERR expression levels were studied by reverse transcriptase-qPCR, ELISA, and immunohistochemistry using endometriotic and normal endometrial tissues. The ERR-α protein distribution was performed by immunohistochemistry in fertile and menopausal women.

Result(s): Increased levels of ER-β were associated with ER-α, ERR-α, and ERR-γ reductions in ectopic tissue but not in eutopic and normal endometria. Similar levels of ERR-β were found in women with and without endometriosis. The ERR-α expression was similar in proliferative and secretory endometrial samples, whereas a down-regulation of this receptor was found in atrophic tissue.

Conclusion(s): Our data confirm the up-regulation of ER-β as the principal receptor involved in the progression of human endometriosis. In addition, we found that ERR-α seems to be unresponsive to hormonal changes during the menstrual cycle.