Role of topical oxytocin in improving vaginal atrophy in postmenopausal women: a randomized, controlled trial

The efficacy of oxytocin gel in postmenopausal women with vaginal atrophy: an updated systematic review and meta-analysis

BACKGROUND

Genitourinary syndrome of menopause (GSM) is a common and disturbing issue in the postmenopausal period. Unlike vasomotor symptoms, it has a progressive trend. Our study aims to evaluate the efficacy and safety of oxytocin gel versus placebo gel in postmenopausal women with GSM.

METHODS

A systematic review and meta-analysis synthesizing randomized controlled trials (RCTs) from Web of Science, SCOPUS, PubMed, and Cochrane Central Register of Controlled Trials databases on January 18, 2023. Keywords such as "oxytocin," "intravaginal," "vaginal," "atrophic," and "atrophy" were used. We used Review Manager (RevMan) version 5.4 in our analysis. We used the risk ratio (RR) for dichotomous outcomes and the mean difference (MD) for continuous outcomes; both were presented with the corresponding 95% confidence interval (CI) and were calculated with the Mantel-Haenszel or inverse variance statistical method. Cochrane's Q test and the I2 statistic were used as measures of statistical inconsistency and heterogeneity. The Cochrane Risk of Bias Tool for RCTs was used for the quality assessment of the included studies.

RESULTS

Seven studies with 631 patients were included. Regarding the maturation index, there was a statistically insignificant increase in the oxytocin arm (MD = 12.34, 95% CI (-12.52-37.19), P = 0.33). Clinically assessed vaginal atrophy showed a statistically significant reduction in the oxytocin group (RR = 0.32, 95% CI (0.23 - 0.10), P < 0.00001). For dyspareunia, vaginal pH, and histological evaluation of vaginal atrophy, there was a statistically insignificant difference between the two groups (RR = 1.02, 95% CI (0.82-1.27), P = 0.84), (MD = -0.74, 95% CI (-1.58-0.10), P = 0.08), and (MD = -0.38, 95% CI (-0.82-0.06), P = 0.09), respectively. There was no significant difference in the safety profile between the two groups as measured by endometrial thickness (MD = 0.00, 95% CI (-0.23-0.23), P = 0.99).

CONCLUSIONS

Although oxytocin has been proposed as a viable alternative to estrogen in the treatment of GSM, our findings show the opposite. Larger, high-quality RCTs are needed to confirm or refute our results.

TRIAL REGISTRATION

PROSPERO registration number CRD42022334357.

Effect of topical oxytocin gel on vaginal mucosa in postmenopausal Egyptian women: a clinical randomized trial

BACKGROUND

Vaginal atrophy is common after menopause and is often linked to sexual dysfunction, particularly dyspareunia.

AIM

The study aimed to investigate the effect of intravaginally applied oxytocin on expressions of vaginal atrophy.

METHODS

Fifty postmenopausal women aged 47 to 66 years with vaginal atrophy participated in this double-blinded placebo-controlled study. The women were randomized to intravaginal treatment with either gel with 600 IU/mL of oxytocin (oxytocin group) or gel alone (control group) once daily for 2 weeks. The gel consisted of hypromellose, pH 3.8 (Vagovital).

OUTCOMES

The color of the vaginal mucosa, the vaginal pH, and the cytology of vaginal epithelial cells were investigated before and after treatment.

RESULTS

The color of the vaginal mucosa shifted from pale to red in all 25 patients treated with oxytocin but only in 4 patients in the control group (P < .001). There was a significant decrease in intravaginal pH in the oxytocin group and the control group, with the delta value being significantly greater in the oxytocin group than in the control group (P < .001). The vaginal maturation index increased significantly (P < .001) in the oxytocin group but not in the control group.

CLINICAL IMPLICATIONS

Topical oxytocin gel offers an effective solution to the sexual dysfunction that is related to vaginal atrophy after menopause.

STRENGTHS AND LIMITATIONS

Strengths include studying different outcomes of applying the oxytocin gel for vaginal atrophy. Limitations include the small-scale population with a relatively short duration of treatment (2 weeks).

CONCLUSION

Intravaginal treatment with a gel containing 600 IU/mL of oxytocin effectively counteracts physical expressions of vaginal atrophy.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05275270; https://clinicaltrials.gov/ct2/show/NCT05275270).

Efficacy of Hormonal and Nonhormonal Approaches to Vaginal Atrophy and Sexual Dysfunctions in Postmenopausal Women: A Systematic Review

OBJECTIVE

 To evaluate the efficacy of the hormonal and nonhormonal approaches to symptoms of sexual dysfunction and vaginal atrophy in postmenopausal women.

DATA SOURCES

 We conducted a search on the PubMed, Embase, Scopus, Web of Science, SciELO, the Cochrane Central Register of Controlled Trials (CENTRAL), and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases, as well as on clinical trial databases. We analyzed studies published between 1996 and May 30, 2020. No language restrictions were applied.

SELECTION OF STUDIES

 We selected randomized clinical trials that evaluated the treatment of sexual dysfunction in postmenopausal women.

DATA COLLECTION

 Three authors (ACAS, APFC, and JL) reviewed each article based on its title and abstract. Relevant data were subsequently taken from the full-text article. Any discrepancies during the review were resolved by consensus between all the listed authors.

DATA SYNTHESIS

 A total of 55 studies were included in the systematic review. The approaches tested to treat sexual dysfunction were as follows: lubricants and moisturizers (18 studies); phytoestrogens (14 studies); dehydroepiandrosterone (DHEA; 8 studies); ospemifene (5 studies); vaginal testosterone (4 studies); pelvic floor muscle exercises (2 studies); oxytocin (2 studies); vaginal CO₂ laser (2 studies); lidocaine (1 study); and vitamin E vaginal suppository (1 study).

CONCLUSION

 We identified literature that lacks coherence in terms of the proposed treatments and selected outcome measures. Despite the great diversity in treatment modalities and outcome measures, the present systematic review can shed light on potential targets for the treatment, which is deemed necessary for sexual dysfunction, assuming that most randomized trials were evaluated with a low risk of bias according to the Cochrane Collaboration risk of bias tool. The present review is registered with the International Prospective Register of Systematic Reviews (PROSPERO; CRD42018100488).

The effect of intra-vaginal oxytocin on sexual function in breastfeeding mothers: a randomized triple-blind placebo-controlled trial

BACKGROUND

Considering the importance of sexual function, high prevalence of sexual dysfunction (especially dyspareunia caused by atrophic vaginitis) in breastfeeding women, and lack of effective interventions, the present research aimed to determine the effect of oxytocin (OXT) vaginal gel on sexual function (primary outcome), sexual satisfaction, and depression (secondary outcomes) in the breastfeeding women.

METHODS

This randomized triple-blind controlled trial was conducted on 64 breastfeeding women who referred to health centers in the city of Tabriz, Iran, in 2020-21. Participants were equally assigned to intervention/control groups using block randomization. 200 IU of OXT vaginal gel was given to the participants in the intervention group daily for eight week and the same protocol was carried out for the control group with placebo. Standard questionnaires of Female Sexual Function Index (FSFI), Edinburgh Postpartum Depression Scale (EPDS) and Sexual satisfaction scale for women (SSSW) were completed at baseline and 8 weeks after intervention. ANCOVA test was used to compare post-intervention mean score of the groups, adjusted for the baseline values.

RESULTS

After intervention, there was no statistically significant difference between groups in terms of mean total score of FSFI (Adjusted Mean Difference (AMD): 1.14; 95% Confidence Interval (95% CI): -1.28 to 9.16; P= 0.349) and sexual satisfaction (AMD: 5.01; 95% CI: -0.53 to 10.56; P= 0.075). However, there was statistically significant difference between the groups in terms of mean scores of sexual contentment (AMD: 1.56; 95% CI: 0.29 to 2.83; P = 0.017) and depression (AMD: -1.90; 95% CI: -1.27 to -2.54; P < 0.001). One participant in the OXT group and one participant in the placebo group reported mild uterine contraction and one person in the placebo group reported vaginal burning sensations.

CONCLUSIONS

No evidence was found for the effects of OXT gel in the improvement of FSFI, even though, OXT significantly improved sexual satisfaction in the domain of contentment, and improved the symptoms of depression in comparison to the placebo group. However, a definite conclusion requires more research in this regard.

TRIAL REGISTRATION

the Iranian Registry of Clinical Trials (IRCT), code: IRCT20120718010324N55 , Date of registration: 27/05/2020, URL: https://en.irct.ir/user/trial/44986/view .

The Microbiome as a Key Regulator of Female Genital Tract Barrier Function

The microbiome, the collection of microbial species at a site or compartment, has been an underappreciated realm of human health up until the last decade. Mounting evidence suggests the microbiome has a critical role in regulating the female genital tract (FGT) mucosa's function as a barrier against sexually transmitted infections (STIs) and pathogens. In this review, we provide the most recent experimental systems and studies for analyzing the interplay between the microbiome and host cells and soluble factors with an influence on barrier function. Key components, such as microbial diversity, soluble factors secreted by host and microbe, as well as host immune system, all contribute to both the physical and immunologic aspects of the FGT mucosal barrier. Current gaps in what is known about the effects of the microbiome on FGT mucosal barrier function are compared and contrasted with the literature of the gut and respiratory mucosa. This review article presents evidence supporting that the vaginal microbiome, directly and indirectly, contributes to how well the FGT protects against infection.

Effects of oxytocin versus promestriene on genitourinary syndrome: a pilot, prospective, randomized, double-blind study

OBJECTIVES

In this pilot, prospective, randomized, double-blind study, the authors compared the efficacy of oxytocin with promestriene in improving vaginal atrophy of Genitourinary Syndrome of Menopause (GSM).

METHODS

A total of 51 postmenopausal women with symptoms of GSM were evaluated. They were randomized into two groups: oxytocin (25 patients) and promestriene (26 patients) and were evaluated before and after 90 days of treatment; the evaluation was based on the domains of the Female Sexual Function Index (FSFI) (lubrication, satisfaction, and pain during sexual intercourse), clinical visual examination, and vaginal wall thickness.

RESULTS

After the use of the medications, both groups showed significant improvement in the three evaluated FSFI domains (p < 0.05) and there was no significant difference between the groups (p > 0.05). On clinical examination, the medications improved all the evaluated parameters but without statistical significance (p > 0.05). The evaluation of the thickness of the vaginal epithelium showed that both treatments led to increase in the vaginal epithelium (p < 0.05); however, the efficacy of promestriene was higher than that of oxytocin (p < 0.05).

CONCLUSIONS

Both medications were effective, however, studies with larger samples and longer follow-ups are needed to confirm the clinical applicability.

Non-oestrogenic modalities to reverse urogenital aging

Urogenital aging is a common process affecting all women in the post-menopausal period of their life, and it is substantially due to oestrogen deprivation after ovarian function cessation. These changes can lead to a progressive, chronic, and complex association of symptoms identified as the genitourinary syndrome of menopause, which has a significant impact on quality of life. Genitourinary syndrome and urogenital aging do not resolve spontaneously and usually recur when treatment is stopped. Therefore, appropriate long-term management is of paramount importance, and local oestrogen is the most effective treatment to reverse urogenital aging and to improve symptoms of genitourinary syndrome as replacement therapy. In some women, topical oestrogen may be inconvenient, it may not achieve complete response, or it may be contra-indicated. Several non-hormonal therapies have been investigated, but few treatments have been reported as potentially able to reverse the urogenital aging process similarly to exogenous oestrogens. Laser seems the most promising, although further studies to define its safety and efficacy are mandatory. Vitamin D and E, and phytotherapy have returned conflicting results and require further confirmation. Lifestyle modifications, physiotherapy, and electrical stimulation represent inexpensive and applicable treatments that might slow urogenital aging. Among the hormonal non-oestrogenic therapies, the use of vaginal oxytocin and dehydroepiandrosterone have been found to be effective compared to placebo, as well as the use of oral ospemifene, which partially relieves vulvovaginal atrophy.

Safety and Efficacy of an Oxytocin Gel and an Equivalent Gel but Without Hormonal Ingredients (Vagivital® Gel) in Postmenopausal Women with Symptoms of Vulvovaginal Atrophy: A Randomized, Double-Blind Controlled Study

Purpose

The primary objective was to compare the efficacy of 12 weeks of daily treatment with Aqueous Hypromellose-based vaginal (Vagivital^®) gel versus Aqueous Hypromellose-based vaginal gel plus 400 IU oxytocin gel in reducing the severity of the most bothersome vulvovaginal atrophy symptoms (MBS: itching, dysuria, bleeding, and pain/discomfort during vaginal sexual activity) observed at baseline. The secondary objectives were to evaluate the other vulvovaginal atrophy symptoms, vaginal pH, superficial squamous cells, and the safety and tolerability of both gels.

Patients and Methods

This double-blind, randomized study evaluated the safety and efficacy of subjects randomly assigned to 12 weeks of daily intravaginal oxytocin gel (n=79) or Aqueous Hypromellose-based vaginal gel (n=78). The efficacy evaluation was performed using data from all included subjects who fulfilled entry criteria.

Results

Both treatments induced statistically significant reductions in the severity of the MBS from baseline until 4 weeks (Vagivital mean reduction 0.90, p=0.0000; Oxytocin mean reduction 0.82, p=0.0000) and 12 weeks post baseline (Vagivital mean reduction 1.28, p=0.0000; Oxytocin mean reduction 1.16, p=0.0000), but the reduction of MBS severity was not significantly different between the treatment groups at either time point. No serious adverse events were reported in the Aqueous Hypromellose-based vaginal gel group during the treatment period, but one (breast cancer) was reported in the oxytocin gel group (assessed as unlikely related to the study compound).

Conclusion

Significant reductions in the severity of the MBS were seen in both the Aqueous Hypromellose-based vaginal gel and the oxytocin gel groups, but with no significant differences in severity reduction seen between the groups. Both gels were safe and well tolerated. Given the benefits of avoiding the use of hormones, Aqueous Hypromellose-based vaginal gel is an attractive first choice in the treatment of postmenopausal women with vulvovaginal atrophy symptoms.

The efficacy and safety of intravaginal oxytocin on vaginal atrophy: A systematic review

Genitourinary syndrome of menopause is a major issue in menopausal health. Because unlike vasomotor symptoms, it has a progressive trend. In this regard we conducted a systematic review to evaluate the efficacy of intravaginal oxytocin on postmenopausal vaginal atrophy. A search was performed for published studies in Cochrane Library, MEDLINE, Web of Science, Embase, Scopus, ProQuest, Google Scholar and Persian databases without time and language limitations. Only randomized controlled trials that compared intravaginal oxytocin with placebos were included. The outcome measures were objective and subjective assessed symptoms of vaginal atrophy. Statistical heterogeneity was evaluated using the I². The standardized mean differences were pooled the fixed effects model. Of the five included studies, four studies meta-analysed. The meta-analysis in terms of the cytological analysis (standardized mean difference: 35.13, 95% confidence interval: 32.59-37.67, n = 218, I² = 96%) was statistically significant. In terms of histological assessments (standardized mean difference: -0.38, 95% confidence interval: -0.94 to 0.17, n = 38, I² = 0%) and endometrial thickness (standardized mean difference: 0.05, 95% confidence interval: -0.20 to -0.31, n = 95, I² = 0%), there were no statistically significant differences between the groups. Three studies reported a statistically significant improvement in the subjective symptoms; however, we were unable to perform a meta-analysis. Four of the included studies assessed side effects, but only two studies reported them. Oxytocin as a nonestrogenic compound can be a suitable alternative for the treatment of vaginal atrophy, especially in women with contraindications for using estrogenic compounds. Further good quality clinical trials with long-term follow-ups are recommended to demonstrate the effects of intravaginal gel in the treatment of vaginal atrophy.

Tri-Phasic Model ofOxytocin (TRIO): A systematic conceptual review of oxytocin-related ERP research

BACKGROUND

The neuropeptide oxytocin (OT) has been shown to play a role in variety of cognitive and social processes and different hypotheses have been put forth to explain OT's effects on brain and behavior in humans. However, these previous explanatory accounts do not provide information about OT-related temporal modulation in the brain.

OBJECTIVES

This paper systematically reviewed intranasal OT administration studies employing event-related potentials (ERPs) and synthesized the existing evidence into a novel conceptual framework.

METHODS

Empirical studies, published until February 2020 and cited in major databases (EBSCOhost, PubMed, and Web of Science), were examined in accordance with PRISMA guidelines. To be included, studies had to: (i) employ intranasal administration of OT, as the chemical modulator; (ii) measure ERPs; (iii) be peer-reviewed journal articles; (iv) be written in English; and (v) examine human participants.

RESULTS

The search criteria yielded 17 empirical studies. The systematic review resulted in conceptualization of the Tri-Phasic Model ofOxytocin (TRIO), which builds on three processing stages: (i) perception, (ii) selection, and (iii) evaluation. While OT increases attention irrespective of stimuli characteristics in the perception stage, in the selection and evaluation stages, OT acts as a filter to guide attention selectively towards social over non-social stimuli and modulates prosociality/approach motivation associated with social stimuli.

CONCLUSIONS

TRIO offers an empirically-derived conceptual framework that can guide the study of OT-related modulation on attentional processes, starting very early in the processing stream. This novel account furthers theoretical understanding and informs empirical investigation into OT modulation on the brain.

The effect of oxytocin vaginal gel on vaginal atrophy in postmenopausal women: a randomized controlled trial

Background

Around 90% of postmenopausal women are suffering from vaginal atrophy. This study aimed to evaluate the effect of oxytocin vaginal gel on vaginal atrophy among postmenopausal women.

Methods

This was a randomized controlled trial that was conducted on 96 postmenopausal women who suffered from vaginal atrophy. The inclusion criteria were: literate women, age 40–60, at least 1 year passed from their last menstrual period or the level of FSH > 40 IU, monogamous women with the sexual relationship. Women in the intervention group, requested to use one applicator of 400 IU oxytocin gel per night and women in the placebo group used placebo each night. The subjective symptoms of vaginal atrophy, vaginal PH, maturation index were measured before and after the intervention.

Results

The number of superficial cells was increased significantly in the oxytocin group compared to placebo (38.7 ± 7.18 vs. 3.69 ± 2.76, p = 0.0001), while the number of parabasal cells was decreased significantly in the oxytocin compared to placebo after the intervention. The improvement of the maturation index was more dominant in the oxytocin group (increased from 7.76 ± 4.68 to 52.48 ± 7.54) in comparison to the placebo group (increased from 8.58 ± 4.35 to 13.25 ± 5.06). The PH of the vagina decreased significantly in the oxytocin group in comparison to the placebo group (p = 0.0001). After 8 weeks, 88.6 and 7.1% of women in the oxytocin and placebo groups did not show the severe symptoms of vaginal atrophy (p = 0.001).

Conclusion

The results of this study showed that eight- week intervention with oxytocin vaginal gel (400 IU) could significantly improve the vaginal maturation index, subjective symptoms of vaginal atrophy and reduce the PH of the vagina. Using this medication in women who have a contraindication for hormone therapy is recommended.

Trial registration

IRCT20160602028220N2.

Oxytocin may have a therapeutical potential against cardiovascular disease. Possible pharmaceutical and behavioral approaches

Based on the ancient role of oxytocin and its homologues as amplifiers of reproduction we argue for an evolutionary coupling of oxytocin to signaling pathway which support restorative mechanisms of cells and tissue. In particular, the survival and function of different categories of stem cells and primordial cells are enhanced by mitogen-activated protein kinase (MAPK) pathways. Furthermore, oxytocin stimulates the AMP-activated protein kinase pathway (AMPK) in numerous of cell types which promotes the maintenance of different cell structures. This involves autophagic processes and, in particular, may support the renewal of mitochondria. Mitochondrial fitness may protect against oxidative and inflammatory stress - a well-documented effect of oxytocin. The combined specific trophic and protective effects oxytocin may delay several degenerative phenomena including sarcopenia, type-2 diabetes and atherosclerosis. These effects may be exerted both on a central level supporting the function and integrity of the hypothalamus and peripherally acting directly on blood vessels, pancreas, heart, skeletal muscles and adipose tissue etc. Furthermore, in the capacity of being both a hormone and neuromodulator, oxytocin interacts with numerous of regulatory mechanisms particularly the autonomic nervous system and HPA-axis which may reduce blood pressure and affect the immune function. The potential of the oxytocin system as a behavioral and molecular target for the prevention and treatment of cardiovascular disease is discussed. Focus is put on the affiliative and sexual significance and the different options and limitations associated with a pharmaceutical approach. MeSH: Aging, Atherosclerosis, Heart, Hypothalamus, Inflammation, Love, Orgasm, Oxytocin.

Chronic oxytocin administration as a tool for investigation and treatment: A cross-disciplinary systematic review

Oxytocin (OT) subserves various physiological, behavioral, and cognitive processes. This paired with the ability to administer OT with minimal and inconsistent side effects has spurred research to explore its therapeutic potential. Findings from single-dose studies indicate that OT administration may be beneficial, at least under certain circumstances. The state of the field, however, is less clear regarding effects from chronic OT administration, which more closely resembles long-term treatment. To address this gap, this review synthesizes existing findings on the use of chronic OT administration in animal and human work. In addition to detailing the effects of chronic OT administration across different functional domains, this review highlights factors that have contributed to mixed findings. Based on this review, a basic framework of interrelated regulatory functions sensitive to chronic OT administration is offered. The paper also identifies future research directions across different contexts, populations, and outcomes, specifically calling for more systematic and standardized research on chronic OT administration in humans to supplement and expand what is currently known from preclinical work.