Estrogen receptor (ER) and ER-related receptor expression in normal and atrophic human vagina

Abstract Objectives The estrogen level decline in menopausal status is involved in physiological alterations of different human tissues including vaginal mucosa. In this study, we have evaluated the estrogen receptor (ER) and estrogen receptor-related receptor (ERR) expression in tissue samples of posterior vaginal wall obtained from pre- and post-menopausal women. Methods The nuclear receptor expression was determined by quantitative real-time PCR (qPCR). Results The qPCR results showed the presence of the three isoforms of the ERR family (ERRα, ERRβ and ERRγ) that were coexpressed with ERs in all vaginal tissue samples examined. The ERRα and ERRγ mRNA levels decreased from normal vagina of the pre-menopausal women to atrophic vaginal tissue in post-menopausal women. This trend was also observed for the ERβ subtype. Conclusions The ERRs, such as ERs, are present in human vagina at the mRNA level and the cessation of ovarian estrogen secretion, that is the key event during the post-menopause, may be linked to ERβ, ERRα and ERRγ mRNA decline in human vaginal mucosa. These findings may provide a biological rationale for the clinical susceptibility of the post-menopausal vagina to local estrogen treatment.