Oestrogen concentrations in plasma, endometrium, myometrium and vagina of postmenopausal women, and effects of vaginal oestriol (E3) and oestradiol (E2) applications

Impact of vaginal estriol on serum hormone levels: a systematic review

The genitourinary syndrome of menopause (GSM) affects up to 84% of postmenopausal women and may significantly reduce the quality of life in some. For symptom relief, there are several non-hormonal and hormonal vaginal products available. In Europe, vaginal estriol (E3) is the most frequently chosen estrogen for GSM treatment. The aim of this systematic review was to assess the impact of vaginal E3 on serum sex hormone levels, an outcome that has been previously used to assess safety in similar products. In our review, we did not find any alterations in serum estrone, estradiol, testosterone, progesterone and sex hormone binding globulin levels after vaginal E3 application. In contrast, some studies showed a minimal and transient decrease in serum gonadotropin levels, which however remained within the postmenopausal range. Similarly, only a few studies reported a minimal and transient increase of serum E3 levels, with the rest reporting no changes. The lack of clinically relevant long-term changes in serum sex hormone levels supports the current literature providing evidence about the safety of vaginal E3 products.

Safety of vaginal estrogens: a systematic review

OBJECTIVE

This systematic review included clinical trials of Food and Drug Administration-approved vaginal estrogens. The primary objective of this systematic review was to examine the comparative safety of the Food and Drug Administration-approved vaginal estrogen preparations among postmenopausal women.

METHODS

We performed a PubMed search of the primary literature from January 1, 1966 to July 16, 2019 for English-language clinical trials. Manual review of retrieved citations identified additional citations.

RESULTS

Of 882 retrieved citations, 75 clinical trials met inclusion criteria. Maximum trial duration was 52 weeks. None of the trials predesignated breast or endometrial cancer, cardiovascular events, or venous thromboembolism as primary outcomes. Studies were not designed to rule out an increase in endometrial carcinoma risk with long-term use of vaginal estrogen. There were few head-to-head comparisons. Fifty trials examined serum sex steroid and gonadotrophin levels; assay methodologies varied. Serum estradiol levels were 11 pg/mL at baseline or during placebo use and increased to a mean of 30 pg/mL after treatment. Estradiol levels were usually highest during the first 12 weeks of treatment, and were higher for estrogen creams than for inserts or rings. The 22 trials of endometrial thickness and the 15 trials of endometrial biopsy did not clearly demonstrate endometrial proliferation after vaginal estrogen treatment, but data were limited, and studies did not always perform systematic endometrial biopsy.

CONCLUSIONS

Newer low-dose estradiol rings, tablets, and inserts appear to induce the least increases in serum hormones, possibly indicating greater safety. Limited evidence in trials lasting up to 52 weeks suggest endometrial safety of vaginal estrogen use. Long-term trials are needed. : Video Summary:http://links.lww.com/MENO/A513.

Serum concentrations of estriol vary widely after application of vaginal oestriol cream

AIMS

The aim of this study was to establish the pharmacokinetic profile of serum oestriol (E₃ ) concentrations over 24 h following application of vaginal E₃ in chronic users (>12 weeks of E₃ use). The interindividual and intraindividual differences before and after E₃ were examined.

METHODS

Ten women participated. Vaginal cream was omitted for ≥36 h prior to the study days. Blood sampling was performed for E₃ , oestradiol and oestrone concentrations prior to cream application and at 1, 2, 3, 5, 8, 10, 12 and 24 h afterwards. In five women, all samples were repeated on a separate day.

RESULTS

E₃ was absorbed rapidly in most women. Peak serum E₃ concentration occurred around 2 h (range 1-5 h). The decline in E₃ concentrations was also rapid: falling <100 pmol L^-1 in six out of ten women within 8 h and returning to ≤ 10 pmol L^-1 at 24 h in nine out of the ten patients. Interindividual variability for peak concentrations was considerable (mean 546 pmol L^-1 ; 95% CI 349-743). Area under the concentration-time curve (AUC) values over a dosage interval also varied widely: mean 2145 pmol.h L^-1 ; 95% CI 1422-3233. However, repeated measurements in the same woman were highly (peaks: ρ = 0.94) or moderately (AUC: P = 0.74) correlated.

CONCLUSIONS

Postmenopausal E₃ concentrations are negligible. Serum E₃ concentrations of chronic users of E₃ cream varied greatly; however, concentrations declined rapidly within 8 h, generally reaching 'postmenopausal' levels by 24 h. The basis for the variation between subjects needs further elucidation. Additional research is required to establish the safety of topical E₃ .

Estriol serum levels in new and chronic users of vaginal estriol cream: A prospective observational study

AIMS

To quantify estriol serum concentrations in "new" and "chronic users" of topical estriol cream using quantitative liquid chromatography tandem mass spectrometry.

METHODS

In this singlecentre prospective observational study, postmenopausal women with urogynaecological complaints were enrolled: 40 had not used topical estriol previously ("new users") and 50 had been applying estriol cream for more than 12 weeks ("chronic users"). In "new users," serum estriol levels were measured at baseline and after 12 weeks use. Estriol cream 1 mg/g was used daily for 3 weeks, then twice weekly with applicator (group 1A) or digitally (group 1B) or three times per week digitally (group 1C). "Chronic users" applied the cream twice (n = 7) or three (n = 43) times per week. Serum samples were taken in the morning after using cream the previous night. The main outcome measures were estriol serum concentrations in "new" and "chronic users" of estriol cream.

RESULTS

Baseline serum estriol concentrations were less than 5 pmol/L in all 40 "new users." At 12 weeks, the 12-hour serum estriol levels ranged from less than 5 to 494 pmol/L (median 22.8; Interquartile range [IQR] 9.2-108.5). Seven "new users" had levels more than 100 pmol/L. Most of the 50 "chronic users" also had 12-hour levels less than 100 pmol/L (median 15.1 pmol/L [IQR 2.7-33.9]: three had levels more than 100 pmol/L.

CONCLUSIONS

This study reports serum estriol concentrations in a large number of "new" and "chronic users" of vaginal estriol cream, employing a novel highly sensitive and specific technique. Overall, the results are reassuring: 87% had 12-hour estriol levels less than 100 pmol/L.

Treatment of vaginal atrophy with estriol and lactobacilli combination: a clinical review

In recent years, a vast quantity of clinical data has been accumulated on the pathophysiology of symptomatic vulvovaginal atrophy (VVA)/genitourinary syndrome of menopause (GSM) in peri- and postmenopausal women and on the treatment options for these conditions. Guidelines from several societies have recently been updated in favor of VVA/GSM vaginal therapy with the lowest possible doses of estrogens. The combination of a vaginal ultra-low dose of 0.03 mg of estriol (E3) and lyophilized, viable Lactobacillus acidophilus KS400 (0.03 mg-E3/L) is a unique product with a dual mechanism of action supporting not only the proliferation and maturation of the vaginal epithelium, but also restoration of the lactobacillary microflora. It has been demonstrated efficiently to establish and maintain a healthy vaginal ecosystem. Use of this combination considerably improves the clinical signs and symptoms as well as the quality of life of menopausal women suffering from vaginal atrophy. This combination therapy is well tolerated with a low overall incidence of side-effects and negligible estriol absorption. Based on recent scientific evidence and current treatment guidelines, the 0.03 mg-E3/L combination could be considered one of the options for the treatment of symptomatic vaginal atrophy in aging menopausal women.

Ultra-low-dose estriol and Lactobacillus acidophilus vaginal tablets (Gynoflor(®)) for vaginal atrophy in postmenopausal breast cancer patients on aromatase inhibitors: pharmacokinetic, safety, and efficacy phase I clinical study

Phase I pharmacokinetic (PK) study assessed circulating estrogens in breast cancer (BC) patients on a non-steroidal aromatase inhibitor (NSAI) with vaginal atrophy using vaginal ultra-low-dose 0.03 mg estriol (E3) and Lactobacillus combination vaginal tablets (Gynoflor^®). 16 women on NSAI with severe vaginal atrophy applied a daily vaginal tablet of Gynoflor^® for 28 days followed by a maintenance therapy of 3 tablets weekly for 8 weeks. Primary outcomes were serum concentrations and PK of E3, estradiol (E2), and estrone (E1) using highly sensitive gas chromatography–mass spectrometry. Secondary outcomes were clinical measures for efficacy and side effects; microscopic changes in vaginal epithelium and microflora; and changes in serum FSH, LH, and sex hormone-binding globulin. Compared with baseline, serum E1 and E2 did not increase in any of the women at any time following vaginal application. Serum E3 transiently increased after the first application in 15 of 16 women, with a maximum of 168 pg/ml 2–3 h post-insertion. After 4 weeks, serum E3 was slightly increased in 8 women with a maximum of 44 pg/ml. The vaginal atrophy resolved or improved in all women. The product was well tolerated, and discontinuation of therapy was not observed. The low-dose 0.03 mg E3 and Lactobacillus acidophilus vaginal tablets application in postmenopausal BC patients during AI treatment suffering from vaginal atrophy lead to small and transient increases in serum E3, but not E1 or E2, and therefore can be considered as safe and efficacious for treatment of atrophic vaginitis in BC patients taking NSAIs.

Hormone replacement therapy in menopausal women: Past problems and future possibilities

Oral administration of conjugated equine estrogens (CEE) with and without the synthetic progestin medroxyprogesterone acetate (MPA) in postmenopausal women is associated with side-effects that include increased risk of stroke and breast cancer. The current evidence that transdermal administration of estradiol may provide a safer alternative to orally administered CEE is reviewed. Transdermally administered estradiol has been shown to be an efficacious treatment for hot flushes possibly without the increase in blood clotting that is associated with administration of oral CEE. Further, natural progesterone may have a more beneficial spectrum of physiological effects than synthetic progestins. The substantial differences between CEE compared with estradiol and estriol, as well as the differences between synthetic MPA and natural progesterone, are detailed. Estriol is an increasingly popular alternative hormone therapy used for menopausal symptoms. There is evidence that estriol, by binding preferentially to estrogen receptor-beta, may inhibit some of the unwanted effects of estradiol. New clinical trials are needed to evaluate the safety and efficacy of topically or transdermally administered combinations of estradiol, estriol and progesterone. Future studies should focus on relatively young women who begin estrogen supplement use near the start of menopause.

Menopause

The area of menopausal medicine is undergoing rapid evolution as millions of baby boomers enter this life stage. This group came of age at a time when all cultural values and institutions, including the basic assumptions underlying the healthcare of women, underwent intense scrutiny. As a result, alternative approaches to everything from childbirth to menopause have become increasingly mainstream. This article gives the healthcare provider both the philosophical background and practical solutions necessary to assist the menopausal woman in choosing an individualized program to minimize her risk for disease and maximize her postmenopausal health potential by combining the best of both conventional and alternative medical approaches.

Biochemical and histological effects of vaginal estriol and estradiol applications on the endometrium, myometrium and vagina of postmenopausal women

Estrogen and progesterone receptors in the cytosol (ERc, PRc) and estrogen receptors in the nuclear compartment (ERn) were measured in the endometrium, myometrium and vagina of 29 postmenopausal women who underwent hysterectomy. The effects of vaginal estriol (0.5 mg daily) compared to 17 beta-estradiol (0.05 mg daily) therapy on these receptor levels were studied. In addition, the endometrium was examined by light microscopy for estrogenic stimulation. We found biochemical and histological signs of estrogenic stimulation in all three tissues after estradiol as well as estriol therapy. In the vagina the effect of both estrogens on the ERc concentration was different from that in the endometrium and myometrium. The effects of estradiol and estriol on the ERn were comparable in all three tissues. The PRc levels increased significantly in all tissues after estrogen therapy; in the myometrium it was significantly higher after estriol than after estradiol applications. In conclusion, there were no clear differences between vaginal estradiol and estriol medication with regard to the effects on receptor levels in vaginal and uterine tissues. In the histological studies at the light microscopy level similar signs of estrogen stimulation of the endometrium were found following estradiol and estriol medication.

Pyrene sulphonyl chloride as a reagent for quantitation of oestrogens in human serum using HPLC with conventional and laser-induced fluorescence detection

A highly sensitive HPLC method with conventional and laser-induced fluorescence detection for the analyses of oestrogens is described. beta-oestradiol (beta-ES) was chosen as a model and derivatized with pyrenesulphonyl chloride (PSCL), a novel derivatizing reagent, using a two-phase system with tetrapentylammonium bromide (TPABR) as a phase transfer catalyst. Derivatization was complete in 30 s at room temperature and concentrations as low as 5 x 10(-10) M could be derivatized and detected. The concentration detection limit PSCL derivatized beta-ES was 2 x 10(-11) M which corresponds to an on-column detection limit of one femtomole using conventional chromatography and detection. The relative standard deviation (n = 6) of the derivatization carried out at 2.5 x 10(-9) M was 4%. No significant loss of peak-height of the derivative was observed at room temperature over 24 h period. Baseline resolution of PSCL derivatized oestrone, equilin and beta-oestradiol was achieved with ACN:H2O (75:25 v/v) using a Bondclone C-18 column. The method described here is sufficiently sensitive for analyses of beta-oestradiol at low pg/mL concentrations in 1 mL of human serum. The PSCL derivatives of oestrogens demonstrate excellent potential for excitation by laser-induced fluorescence using the 351 nm line of an Ar ion laser or the 325 nm line of He-Cd laser. A concentration limit of detection of 4 x 10(-12) M for beta-oestradiol was achieved using the 325 nm line of an He-Cd laser. This corresponds to 0.2 fmol of derivatized beta-oestradiol on-column.

A morphologist's approach to the vagina--age-related changes and estrogen sensitivity

This paper reviews basic facts on vagina histology and ultrastructure with respect to passage of different substances and drugs through the epithelium. Particular interest is devoted to the action mechanism of topically-applied vaginal estrogen, its binding to receptors in different vaginal cell types, and possible local metabolic routes. Differences in estrogen sensitivity between uterus and vagina are discussed as well as the background for the high vaginal sensitivity.

Preoperative treatment with oestradiol in women scheduled for vaginal operation for genital prolapse. A randomised, double-blind trial

OBJECTIVE

To disclose a clinical and histopathological effect of local low-dose oestradiol treatment on the vagina.

DESIGN

A randomised, double-blind trial.

SETTING

Two gynaecological departments at University Hospitals.

SUBJECTS

Forty-eight postmenopausal women scheduled for surgery because of genital prolapse.

INTERVENTION

25 micrograms oestradiol or placebo, administered as vaginal pessaries daily, 3 weeks prior to surgery.

MAIN OUTCOME MEASURES

Cytological, histological and clinical changes of the vaginal mucosa.

RESULTS

The thickness of the vaginal wall increased as did the oestrogenic index. No clinical effect was seen apart from decreased incidence of recurrent cystitis postoperatively.

CONCLUSIONS

Preoperative oestrogen treatment has been shown to reduce the incidence of recurrent cystitis and may be needed for stimulation of vaginal mucosa; the short-term clinical effect is not convincing, however.

Long-term treatment of atrophic vaginitis with low-dose oestradiol vaginal tablets

Fifty-one post-menopausal women suffering from symptoms of oestrogen deficiency-derived atrophic vaginitis were treated intravaginally with two therapeutic regimens based on doses of 25 micrograms 17 beta-oestradiol (E2) in an open, controlled study. All the patients received treatment daily for 2 weeks by way of induction therapy. They were then randomly allocated to either once-weekly (17 patients) or twice-weekly (34 patients) vaginal administration for a further 50 weeks as maintenance treatment. Endometrial histopathology was evaluated before and after 1 year of treatment. The effects on symptoms and oestrogen/gonadotrophin levels were determined before and after 2, 12, 24, 36 and 52 weeks of therapy. Nine women continued twice-weekly treatment for a further year, meaning that they underwent treatment for a total period of 2 years. Endometrial biopsies were obtained after 2 years of treatment. All the pretreatment endometrial biopsies indicated an atrophic endometrium. One patient out of the 14 who completed 1 year of therapy in the group treated once weekly showed weak proliferation of the endometrium, while the other 13 had an atrophic endometrium. In the group treated twice weekly, 2 out of the 31 patients who completed the study showed weak proliferation of the endometrium. The other 29 had an atrophic endometrium. All 9 women who received treatment for 2 years had an atrophic endometrium at the end of the treatment period. The twice-weekly dosage regimen gave complete relief of symptoms in almost all patients, whereas the majority of the patients in the group treated once weekly still had mild symptoms. No adverse effects were reported.(ABSTRACT TRUNCATED AT 250 WORDS)