Regeneration of the structure and function of estrogen-deficient vaginal epithelium by a novel phytoestrogen-related...

The loss of estradiol production that accompanies natural aging or therapeutic intervention (oophorectomy or estrogen suppression) precipitates atrophic changes in the vaginal epithelium responsible for a plethora of symptoms that, collectively, are termed genitourinary syndrome of menopause. While systemic or local hormone replacement therapy can ameliorate these symptoms, their use faces resistance from women and their physicians concerned about the risks of estrogen therapy. The goal of this study is to evaluate an alternative approach to reversing vaginal atrophy that follows the loss of estradiol.

This study employs the ovariectomized rat model of menopause. Ovariectomized rats exhibit atrophic changes in the vaginal epithelium, much like humans. We delivered a novel estrogenic flavone, 3-fluoro 6,4'-dihydroxyflavone (3F), by vaginal suppository. This compound was developed and chosen for modest potency as an estrogen and inactivation once in the circulation to minimize the potential for systemic activity.

Vaginal administration of this flavone regenerates the structure of atrophic vaginal epithelium. This is accompanied by restoration of mucin secretion and expression of anti-microbial proteins. Greater mucin expression is seen following 3F-treatment compared with estradiol. Vaginal regeneration is accomplished without stimulating cell proliferation in the vagina or endometrial epithelium.

The combination of local delivery, modest potency, liver metabolism, and elimination creates safeguards that support the potential for human use of 3F to alleviate symptoms associated with estrogen-deficient vaginal atrophy without the risks of systemic hormone therapy or local steroidal estrogens.