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Estrogen acidifies vaginal pH by up-regulation of proton secretion via the apical membrane of vaginal-ectocervical epithelial cells.

ABSTRACT: The objective of this study was to assess estrogen-dependent cellular mechanisms that could contribute to the acid pH of the vaginal lumen. Cultures of normal human cervical-vaginal epithelial (hECE) cells and endocervical cells were grown on filters, and acidification of the extracellular solutions on the luminal (L-pHo) and contraluminal (CL-pHo) sides was measured. The hECE cells and endocervical cells decreased CL-pHo from 7.40 to 7.25 within 20-30 min of incubation in basic salt solution. Endocervical cells also produced a similar decrease in L-pHo. In contrast, hECE cells acidified L-pHo down to pH 7.05 when grown as monoculture and down to pH 6.05 when grown in coculture with human cervical fibroblasts. This enhanced acid secretion into the luminal compartment was estrogen dependent because removal of endogenous steroid hormones attenuated the effect, whereas treatment with 17beta-estradiol restored it. The 17beta-estradiol effect was dose dependent (EC50 0.5 nm) and could be mimicked by diethylstilbestrol and in part by estrone and tamoxifen. Preincubation with ICI-182780, but not with progesterone, blocked the estrogen effect. Preincubation of cells with the V-ATPase blocker bafilomycin A1, when administered to the luminal solution, attenuated the baseline and estrogen-dependent acid secretion into the luminal solution. Treatment with EGTA, to abrogate the tight junctional resistance, blocked the decrease in L-pHo and stimulated a decrease in CL-pHo, indicating that the tight junctions are necessary for maintaining luminal acidification. We conclude that vaginal-ectocervical cells acidify the luminal canal by a mechanism of active proton secretion, driven in part by V-H+-ATPase located in the apical plasma membrane and that the baseline active net proton secretion occurs constitutively throughout life and that this acidification is up-regulated by estrogen.

SUBMITTER: Gorodeski GI

PROVIDER: S-EPMC2398721 | biostudies-literature | 2005 Feb

REPOSITORIES: biostudies-literature

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Estrogen acidifies vaginal pH by up-regulation of proton secretion via the apical membrane of vaginal-ectocervical epithelial cells.

Gorodeski George I GI Hopfer Ulrich U Liu Chung Chiun CC Margles Ellen E

Endocrinology 20041021 2

The objective of this study was to assess estrogen-dependent cellular mechanisms that could contribute to the acid pH of the vaginal lumen. Cultures of normal human cervical-vaginal epithelial (hECE) cells and endocervical cells were grown on filters, and acidification of the extracellular solutions on the luminal (L-pHo) and contraluminal (CL-pHo) sides was measured. The hECE cells and endocervical cells decreased CL-pHo from 7.40 to 7.25 within 20-30 min of incubation in basic salt solution. E ...[more]

PMID: 15498880

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Project description:ObjectiveTo understand estrogen regulation of proton (H(+)) secretion by human vaginal-ectocervical epithelial cells and the mechanisms involved.DesignPrimary-tertiary cultures of human normal vaginal-ectocervical epithelial cells were generated from surgical specimens of premenopausal women (aged 37-46 years) and of postmenopausal women (aged 53-65 years). Cells were grown on filters, and measurements were made of changes in extracellular pH (pHo) in the contraluminal (CL) and luminal (L) solutions 30 minutes after shifting cells to basic salt solution.ResultsUpon shifting cells to basic salt solution, CL-pHo decreased from 7.4 to 7.25, and was not affected by removal of intracellular estrogens or treatment with estradiol. L-pHo decreased from 7.4 to 7.05 in cells of premenopausal women, and from 7.4 to 7.20 in cells of postmenopausal women. Removal of intracellular estrogens attenuated the decrease in L-pHo in cells of premenopausal women (only to 7.20). In cells of premenopausal women stripped of estrogens, treatment with 10 nM 17beta-estradiol restored the decrease in L-pHo. In estrogen-stripped cells of postmenopausal women, treatment with estradiol augmented luminal acidification but to a lesser degree than in cells of premenopausal women (L-pHo of 7.15 vs 7.05). In cells of pre- and postmenopausal women, the addition in the L solution of bafilomycin-A(1), a specific inhibitor of the vacuolar-H(+)-ATPase (V-H(+)-ATPase), blocked the decrease in L-pHo.ConclusionsHuman vaginal-ectocervical epithelial cells acidify constitutively their luminal solution, and the effect is mediated by active H(+) secretion by V-H(+)-ATPase expressed predominantly in the apical cell membrane. Estrogen deprivation attenuates, and treatment with 17beta-estradiol augments, active H(+) secretion. Finally, cells of postmenopausal women actively secrete H(+) via apically located V-H(+)-ATPase, but the effect is lesser, and estrogen failed to augment active H(+) secretion, as in cells of premenopausal women. These data suggest that in addition to hypoestrogenism, other factors of the aging process affect the capacity of vaginal-ectocervical cells to secrete acid.

Project description:ImportanceSurgical repairs of apical/uterovaginal prolapse are commonly performed using native tissue pelvic ligaments as the point of attachment for the vaginal cuff after a hysterectomy. Clinicians may recommend vaginal estrogen in an effort to reduce prolapse recurrence, but the effects of intravaginal estrogen on surgical prolapse management are uncertain.ObjectiveTo compare the efficacy of perioperative vaginal estrogen vs placebo cream on prolapse recurrence following native tissue surgical prolapse repair.Design, setting, and participantsThis randomized superiority clinical trial was conducted at 3 tertiary US clinical sites (Texas, Alabama, Rhode Island). Postmenopausal women (N = 206) with bothersome anterior and apical vaginal prolapse interested in surgical repair were enrolled in urogynecology clinics between December 2016 and February 2020.InterventionsThe intervention was 1 g of conjugated estrogen cream (0.625 mg/g) or placebo, inserted vaginally nightly for 2 weeks and then twice weekly to complete at least 5 weeks of application preoperatively; this continued twice weekly for 12 months postoperatively. Participants underwent a vaginal hysterectomy (if uterus present) and standardized apical fixation (either uterosacral or sacrospinous ligament fixation).Main outcomes and measuresThe primary outcome was time to failure of prolapse repair by 12 months after surgery defined by at least 1 of the following 3 outcomes: anatomical/objective prolapse of the anterior or posterior walls beyond the hymen or the apex descending more than one-third of the vaginal length, subjective vaginal bulge symptoms, or repeated prolapse treatment. Secondary outcomes included measures of urinary and sexual function, symptoms and signs of urogenital atrophy, and adverse events.ResultsOf 206 postmenopausal women, 199 were randomized and 186 underwent surgery. The mean (SD) age of participants was 65 (6.7) years. The primary outcome was not significantly different for women receiving vaginal estrogen vs placebo through 12 months: 12-month failure incidence of 19% (n = 20) for vaginal estrogen vs 9% (n = 10) for placebo (adjusted hazard ratio, 1.97 [95% CI, 0.92-4.22]), with the anatomic recurrence component being most common, rather than vaginal bulge symptoms or prolapse repeated treatment. Masked surgeon assessment of vaginal tissue quality and estrogenization was significantly better in the vaginal estrogen group at the time of the operation. In the subset of participants with at least moderately bothersome vaginal atrophy symptoms at baseline (n = 109), the vaginal atrophy score for most bothersome symptom was significantly better at 12 months with vaginal estrogen.Conclusions and relevanceAdjunctive perioperative vaginal estrogen application did not improve surgical success rates after native tissue transvaginal prolapse repair.Trial registrationClinicalTrials.gov Identifier: NCT02431897.

Dataset Information

Estrogen acidifies vaginal pH by up-regulation of proton secretion via the apical membrane of vaginal-ectocervical epithelial cells.

Publications

Estrogen acidifies vaginal pH by up-regulation of proton secretion via the apical membrane of vaginal-ectocervical epithelial cells.

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