Expression of estrogen receptor-alpha and -beta in anterior vaginal walls of genuine stress incontinent women.

Our objective was to study the expression of estrogen receptor (ER) isoforms, ER-alpha and ER-beta, in the anterior vaginal wall of menopausal and fertile women with genuine stress incontinence (SI) by immunohistochemistry and Western blot analysis. Eighteen menopausal women with SI who either were or were not taking estrogen/progestin replacement therapy and 14 fertile women with SI who either were or were not taking contraceptives were enrolled in the study. Biopsies from the suburethral anterior vaginal wall were obtained at tension-free vaginal tape (TVT) operation. Monoclonal antibody to ER-alpha and polyclonal antibody to ER-beta were used to stain frozen sections of vaginal tissue. The receptor expressions were scored based on percentage of positive cells. ER-alpha was detected in vaginal epithelial, stromal and smooth muscle cells. In menopausal SI women ER-alpha was detected significantly more frequently in the vaginal walls of estrogen/progestin-treated patients than in those who were untreated. Fertile SI women had significantly higher expression of ER-alpha than menopausal SI women. ER-alpha was not observed in vaginal blood vessels. ER-beta was detected in epithelial and vascular smooth muscle cells of the vagina. No significant difference in ER-beta expression was observed between different groups of patients. The expression of ER-alpha was not correlated with that of ER-beta. Both ER-alpha and -beta were detected, indicating a potential role for both types of estrogen receptor in the human vaginal wall. The expression of ER-alpha, but not of ER-beta, in menopausal SI women was regulated by estrogen/progestin replacement therapy. The presence of ER-beta in vaginal vascular smooth muscle cells raises the possibility of vascular effects of estrogen on the human vaginal wall.