The effect of medroxyprogesterone acetate on estrogen-dependent risks and benefits--an attempt to interpret the Women's Health Initiative results

Oral estradiol/micronized progesterone may be associated with lower risk of venous thromboembolism compared with conjugated equine estrogens/medroxyprogesterone acetate in real-world practice

OBJECTIVES

The Women's Health Initiative study reported an increased risk of venous thromboembolism among menopausal women treated with conjugated equine estrogens/medroxyprogesterone acetate (CEE/MPA) versus placebo. Newer hormone therapies may have a lower venous thromboembolism risk. The study compared the risk of venous thromboembolism between women treated with the combined oral product 17β-estradiol/micronized progesterone (E2/P4) and those treated with oral CEE/MPA regimens.

STUDY DESIGN

In a retrospective longitudinal study using real-world claims data from April 2019 to June 2021, women aged 40 years or more treated with oral E2/P4 or oral CEE/MPA who did not have a venous thromboembolism diagnosis before first dispensing claim of CEE/MPA or E2/P4 identified on or after May 1st 2019 (index date) were observed for 6 months or more after the index date. Oral E2/P4 and oral CEE/MPA had been prescribed by the treating physician in real-world practice and were observed through pharmacy dispensing records.

MAIN OUTCOME MEASURES

Venous thromboembolism risk was compared between women receiving oral E2/P4 versus oral CEE/MPA.

RESULTS

The study included 36,061 women treated with oral E2/P4 or oral CEE/MPA. In the analyses weighted by the inverse probability of treatment for control of potential confounding factors, the incidence of venous thromboembolism was significantly lower for oral E2/P4 compared with oral CEE/MPA (37/10,000 women-years for oral E2/P4 vs 53/10,000 women-years for oral CEE/MPA; incidence rate ratio 0.70, 95 % confidence interval: 0.53-0.92).

CONCLUSIONS

Real-world evidence suggests that the risk of venous thromboembolism is significantly lower among women treated with oral E2/P4 compared with oral CEE/MPA.

Development of a novel progesterone analog in the treatment of traumatic brain injury

Although systemic progesterone (PROG) treatment has been shown to be neuroprotective by many laboratories and in multiple animal models of brain injury including traumatic brain injury (TBI), PROG's poor aqueous solubility limits its potential for use as a therapeutic agent. The problem of solubility presents challenges for an acute intervention for neural injury, when getting a neuroprotectant to the brain quickly is crucial. Native PROG (nPROG) is hydrophobic and does not readily dissolve in an aqueous-based medium, so this makes it harder to give under emergency field conditions. An agent with properties similar to those of PROG but easier to store, transport, formulate, and administer early in emergency trauma situations could lead to better and more consistent clinical outcomes following TBI. At the same time, the engineering of a new molecule designed to treat a complex systemic injury must anticipate a range of translational issues including solubility and bioavailability. Here we describe the development of EIDD-1723, a novel, highly stable PROG analog with >10⁴-fold higher aqueous solubility than that of nPROG. We think that, with further testing, EIDD-1723 could become an attractive candidate use as a field-ready treatment for TBI patients. This article is part of the Special Issue entitled "Novel Treatments for Traumatic Brain Injury".

Depo-Provera (depot medroxyprogesterone acetate) use after bariatric surgery

In the US, obesity rates are increasing greatly. The Centers for Disease Control and Prevention estimates that 68.5% of Americans, including 63.9% of adult women older than 20 years, are overweight (body mass index between 25 kg/m² and 29.9 kg/m²) or obese (body mass index >30 kg/m²). In light of this, it is not surprising that the rates of bariatric surgery have also been increasing. When considering the metabolic changes associated with both bariatric surgery and contraceptive use, in combination with the unique medical considerations of obese women, it is indisputable that clear guidelines are needed when counseling obese patients of reproductive age after bariatric surgery. In this literature review, we focus on depot medroxyprogesterone acetate (DMPA) and the implications of its use in obese women, preweight and postweight loss following bariatric surgery. Both DMPA use and bariatric surgery are known to cause bone loss, but it is still unclear whether there is an additive effect of the two factors on bone loss and whether either of these factors directly leads to an increased risk of bone fracture. The current consensus guidelines do not impose a restriction on the use of DMPA after bariatric surgery. DMPA use is associated with weight gain, and it is unclear whether weight loss blunting occurs with the use of DMPA after bariatric surgery. Prior studies had demonstrated an association with weight gain in adolescents, and therefore, those prescribing DMPA use after bariatric surgery in adolescents should proceed with caution. Adult women do not have a similar response to the use of DMPA. DMPA use has rarely been associated with increased risk of venous thromboembolism (VTE). The obesity-associated increase in VTE should be mitigated by surgically induced weight loss. The concurrent use of DMPA in the post bariatric surgical period should not further increase the risk of VTE.

Significant role of estrogen in maintaining cardiac mitochondrial functions

Increased susceptibility to stress-induced myocardial damage is a significant concern in addition to decreased cardiac performance in postmenopausal females. To determine the potential mechanisms underlying myocardial vulnerability after deprivation of female sex hormones, cardiac mitochondrial function is determined in 10-week ovariectomized rats (OVX). Significant mitochondrial swelling in the heart of OVX rats is observed. This structural alteration can be prevented with either estrogen or progesterone supplementation. Using an isolated mitochondrial preparation, a decrease in ATP synthesis by complex I activation in an OVX rat is completely restored by estrogen, but not progesterone. At basal activation, reactive oxygen species (ROS) production from the mitochondria is not affected by the ovariectomy. However, after incubated in the presence of either high Ca(2+) or antimycin-A, there is a significantly higher mitochondrial ROS production in the OVX sample compared to the control. This increased stress-induced ROS production is not observed in the preparation isolated from the hearts of OVX rats with estrogen or progesterone supplementation. However, deprivation of female sex hormones has no effect on the protein expression of electron transport chain complexes, mitofusin 2, or superoxide dismutase 2. Taken together, these findings suggest that female sex hormones, estrogen and progesterone, play significant regulatory roles in maintaining normal mitochondrial properties by stabilizing the structural assembly of mitochondria as well as attenuating mitochondrial ROS production. Estrogen, but not progesterone, also plays an important role in modulating mitochondrial ATP synthesis.

Selective Estrogen Receptor Modulation by Larrea nitida on MCF-7 Cell Proliferation and Immature Rat Uterus

Larrea nitida is a plant that belongs to the Zygophyllaceae family and is widely used in South America to treat inflammatory diseases, tumors and menstrual pain. However, its pharmacological activity remains unclear. In this study we evaluated the property of selective estrogen receptor modulator (SERM) of Larrea nitida extracts (LNE) as a phytoestrogen that can mimic, modulate or disrupt the actions of endogenous estrogens, depending on the tissue and relative amount of other SERMs. To investigate the property of SERM of LNE, we performed MCF-7 cell proliferation assays, estrogen response element (ERE)-luciferase reporter gene assay, human estrogen receptor (hER) binding assays and in vivo uterotrophic assay. To gain insight into the active principles, we performed a bioassay-guided analysis of LNE employing solvents of various polarities and using classical column chromatography, which yielded 16 fractions (LNs). LNE showed high binding affinities for hERα and hERβ with IC₅₀ values of 1.20 ×10⁻⁷ g/ml and 1.00×10⁻⁷ g/ml, respectively. LNE induced 17β-estradiol (E2)-induced MCF-7 cell proliferation, however, it reduced the proliferation in the presence of E2. Furthermore, LNE had an atrophic effect in the uterus of immature rats through reducing the expression level of progesterone receptor (PR) proteins. LN08 and LN10 had more potent affinities for binding on hER α and β than other fractions. Our results indicate that LNE had higher binding affinities for hERβ than hERα, and showed SERM properties in MCF-7 breast cancer cells and the rat uterus. LNE may be useful for the treatment of estrogen-related conditions, such as female cancers and menopause.

Therapeutic effect of dienogest on adenosarcoma arising from endometriosis: a case report

Dienogest is a novel synthesized progestin used for treatment of endometriosis. This is the first case report describing a therapeutic effect of dienogest on a gynecologic malignancy. The patient was a 44-year-old woman with advanced adenosarcoma arising from the endometriosis in the rectovaginal space and infiltrating the left pelvic wall, left ureter, rectum and vagina. The residual tumor after tumor debulking surgery was resistant to both chemotherapy and radiotherapy. Dienogest was used as a substitute for medroxyprogesterone acetate because of the presence of deep vein thrombosis. Based on the RECIST criteria, partial response was obtained with oral dienogest therapy at six months and the serum CA125 level also decreased from 70 U/ml to 16 U/ml. The tumor remained stable up to 21 months. Thromboembolism or other adverse effects did not occur during the dienogest therapy. Dienogest may be useful for the treatment of adenosarcoma arising from endometriosis.

Biological characterization of non-steroidal progestins from botanicals used for women's health

Progesterone plays a central role in women's reproductive health. Synthetic progestins, such as medroxyprogesterone acetate (MPA) are often used in hormone replacement therapy (HRT), oral contraceptives, and for the treatment of endometriosis and infertility. Although MPA is clinically effective, it also promiscuously binds to androgen and glucocorticoid receptors (AR/GR) leading to many undesirable side effects including cardiovascular diseases and breast cancers. Therefore, identifying alternative progestins is clinically significant. The purpose of this study was to biologically characterize non-steroidal progestins from botanicals by investigating theirinteraction and activation of progesterone receptor (PR). Eight botanicals commonly used to alleviate menopausal symptoms were investigated to determine if they contain progestins using a progesterone responsive element (PRE) luciferase reporter assay and a PR polarization competitive binding assay. Red clover extract stimulated PRE-luciferase and bound to PR. A library of purified compounds previously isolated from red clover was screened using the luciferase reporter assay. Kaempferol identified in red clover and a structurally similar flavonoid, apigenin, bound to PR and induced progestegenic activity and P4 regulated genes in breast epithelial cells and human endometrial stromal cells (HESC). Kaempferol and apigenin demonstrated higher progestegenic potency in the HESC compared to breast epithelial cells. Furthermore, phytoprogestins were able to activate P4 signaling in breast epithelial cells without downregulating PR expression. These data suggest that botanical extracts used for women's health may contain compounds capable of activating progesterone receptor signaling.

Update: Estrogen and Estrogen plus Progestin Therapy in the Care of Women at and after the Menopause

Much new information on menopausal hormone therapy (MHT) has become available since the publication of the first report of the Women's Health Initiative in 2002 and a consensus is now emerging. The risk of breast cancer depends on type of MHT, duration of use, body mass, breast density and interval between menopause and starting MHT. The risk of breast cancer is generally increased by MHT, particularly in lean women with no previous MHT who start estrogen–progestin therapy near the menopause and continue for several years, but there is no increased risk 5 years after stopping MHT. The risks of venous thrombo-embolic disease (VTE), stroke and coronary heart disease (CHD) depend on age on starting MHT, dose, nature and route of administration of MHT. The risk of VTE is increased in women over 60 years of age and in women who are obese or have had a VTE but may not be increased by transdermal estrogens. The risk of stroke is very small in women under 60 years of age and may not be increased by low dose oral and low dose transdermal estrogen, MHT is of benefit in preventing atherosclerosis and CHD in healthy younger postmenopausal women (under the age of 60) but is not of benefit, and may be harmful, in older women with clinical or subclinical atherosclerosis. MHT prevents bone loss and osteoporosis but is not generally recommended in women over 60 because of the risks of VTE, stroke and CHD, and if stopped at 60 years does not prevent fractures in later life. MHT reduces the overall mortality in women under 60. MHT is by far the most effective treatment, and greatly improves the quality of life in women with menopausal symptoms. A simplified approach to MHT is suggested as a framework for the care of women at and after the menopause.

Vasomotor hot flushes and 24-hour ambulatory blood pressure in normotensive women: A placebo-controlled trial on post-menopausal hormone therapy

BACKGROUND

Blood pressure (BP) is one of the most powerful determinants of cardiovascular risk in women. This risk may differ between post-menopausal women with and without vasomotor hot flushes, possibly indicating different vascular responses to hormone therapy (HT). Thus, we compared in a clinical trial the effect of HT on ambulatory BP in normotensive, recently post-menopausal women with or without severe hot flushes.

METHODS

A total of 147 women recorded prospectively their hot flushes for 2 weeks; 70 women were symptomatic (>or=7 moderate/severe hot flush episodes/day), whereas 77 women were defined as asymptomatic (<or=3 mild hot flush episodes/day). Women were treated for 6 months with either transdermal estradiol, oral estradiol with or without medroxyprogesterone acetate, or placebo.

RESULTS

In symptomatic women decreases in BPs were seen during estradiol use. In contrast, in asymptomatic women receiving oral but not transdermal estradiol, increases in 24-h and day-time systolic and diastolic BPs were encountered.

CONCLUSION

Hot flushes modify the HT-mediated responses in ambulatory BP. In asymptomatic women oral but not transdermal estradiol show potentially harmful cardiovascular effect by increasing BP. Our results give additional justification to prescribing HT primarily for the treatment of troublesome hot flushes and avoiding HT in women without vasomotor symptoms.

Can 19-nortestosterone derivatives be aromatized in the liver of adult humans? Are there clinical implications?

CONTEXT

Previous studies in postmenopausal women have demonstrated that, after oral administration of norethisterone, a small proportion of the compound is rapidly converted into ethinylestradiol. The shape of the concentration - time curve suggested that this occurred in the liver. The results were confirmed by in vitro investigations with adult human liver tissue. In 2002, it was shown that, after oral treatment of women with tibolone, aromatization of the compound occurred, resulting in the formation of a potent estrogen, 7 alpha-methyl-ethinylestradiol. The result has been called into question, because the adult human liver does not express cytochrome P450 aromatase, which is encoded by the CYP 19 gene. Moreover, it has been claimed that the serum level of 7 alpha-methyl-ethinylestradiol measured by gas chromatography/mass spectrometry was an artifact.

REPLY

Aromatization of steroids is a complex process of consecutive oxidation reactions which are catalyzed by cytochrome P450 enzymes. The conversion of the natural C19 steroids, testosterone and androstenedione, into estradiol-17beta and estrone is dependent on the oxidative elimination of the angular C19-methyl group. This complex key reaction is catalyzed by the cytochrome P450 aromatase, which is expressed in many tissues of the adult human (e.g. ovary, fat tissue), but not in the liver. However, 19-nortestosterone derivatives are characterized by the lack of the C19-methyl group. Therefore, for the aromatization of these synthetic steroids, the action of the cytochrome P450 aromatase is not necessary and the oxidative introduction of double bonds into the A-ring can be catalyzed by other hepatic cytochrome P450 enzymes. The final key process in the formation of a phenolic A-ring, both in natural androgens and 19-nortestosterone derivatives, is the enolization of a 3-keto group to the C2-C3-enol or the C3-C4-enol moiety, which occurs without the action of enzymes.

CONCLUSION

19-nortestosterone derivatives (norethisterone, norethynodrel, tibolone) can readily be aromatized in the adult human liver. This leads to the formation of the potent estrogens ethinylestradiol from norethisterone or norethynodrel and 7 alpha-methyl-ethinylestradiol from tibolone. This may have clinical consequences, e.g. the elevated risk of venous thromboembolic disease in premenopausal women treated with high doses of norethisterone for bleeding disorders, or the elevated risk of stroke or endometrial disease in postmenopausal women treated with tibolone.

Effects of estrogen and estrogen-progesteron on serum nitric oxide metabolite concentrations in post-menopausal women

Estrogens have some anti-atherosclerotic properties and they influence nitric oxide (NO) production. The aim of this study was to determine NOx levels in post-menopausal women and the effect of estrogen/estrogen-progesteron therapy (ET/EPT) on plasma NO levels. Eighty postmenopausal women (M1) comprising 26 with surgically induced menopause (ET1), mean age 50.9+/-2.9 yr, and 54 with physiological menopause (EPT1), mean age 50.5+/-3.0 yr, were studied. Forty healthy pre-menopausal women, mean age 48.3+/-2.3 yr were the controls (C). The post-menopausal women were treated for 4 months: group ET1 with ET and group EPT1 with EPT. Serum estradiol (E2), FSH, NOx and lipid profile before and after therapy were measured. NOx levels were lower in group M1 than in group C (8.75+/-1.57 vs 10.27+/-2.62, p<0.01) and increased after hormonal therapy (10.65+/-2.38). NOx concentration showed significant positive correlation with E2 (r=0.25, p<0.05). Total cholesterol (240.9+/-43.2), LDL-cholesterol (155.2+/-33.6), triglycerides (124.8+/-54.1), and apolipoprotein B (1.52+/-0.33) were higher in group M1 than in group C (223.1+/-44.3, 133.0+/-38.2, 108.3+/-52.9, and 1.12+/-0.36, respectively), and after ET/EPT they decreased to the values observed in group C. There were no correlations between NO and lipids or apolipoproteins.

CONCLUSIONS

ET and EPT improve NOx synthesis and endothelial relaxation. Medroxyprogesterone acetate added to E2 does not significantly influence NOx levels.

Association between hormone replacement therapy and subsequent arterial and venous vascular events: a meta-analysis

AIMS

Randomized controlled trials (RCTs) have shown that the risk of stroke and venous thromboembolism (VTE) is increased with hormone replacement therapy (HRT); the effect on coronary heart disease (CHD) remains unclear.

METHODS AND RESULTS

RCTs of HRT were identified. Event rates for cerebrovascular disease [stroke, TIA (transient ischaemic attack)], CHD (myocardial infarction, unstable angina, sudden cardiac death), and VTE (pulmonary embolism, deep vein thrombosis) were analysed. Sensitivity analyses were performed by type of HRT (mono vs. dual) and subject age. 31 trials (44 113 subjects) were identified. HRT was associated with increases in stroke (odds ratio, OR, 1.32, 95% confidence intervals, CI, 1.14-1.53) and VTE (OR 2.05, 95% CI 1.44-2.92). In contrast, CHD events were not increased (OR 1.02, 95% CI 0.90-1.11). Ordinal analyses confirmed that stroke severity was increased with HRT (OR 1.31, 95% CI 1.12-1.54). Although most trials included older subjects, age did not significantly affect risk. The addition of progesterone to oestrogen doubled the risk of VTE.

CONCLUSION

HRT is associated with an increased risk of stroke, stroke severity, and VTE, but not of CHD events. Although most trials studied older patients, increased risk was not related to age. Combined HRT increases the risk of VTE compared with oestrogen monotherapy.

Bioidentical Hormone Therapy: A Review of the Evidence

Bioidentical hormone therapy (BHT) uses bioidentical hormones (BHs), derivatives of plant extracts chemically modified to be structurally indistinguishable from human endogenous hormones. BHTs are available commercially or can be compounded into different dosages and for different routes of administration. Typically, compounded preparations of BHs may include estriol, estrone, estradiol, testosterone, micronized progesterone, and occasionally dehydroepiandrosterone (DHEA). It is generally accepted that estrogen-based hormone therapies share similar efficacies as well as risks. Many FDA-approved and regulated pharmaceutically manufactured and branded conventional hormone therapies (CHTs) employ BHs. Since the publication of the Women's Health Initiative (WHI) trial results publicizing an increased risk of stroke, venous thrombosis, and breast cancer and no beneficial effect on coronary heart disease (CHD), use of CHT has declined, and there has been increased interest in alternative approaches. This review of the literature related to compounded BHT and the practices of its advocates is to determine if sufficient scientific evidence supports claims of greater efficacy and safety and any additional risks and uncertainties not generally associated with CHTs. Compounded BHTs have been promoted by some as natural, safer, and in some cases more efficacious than conventional hormone therapies, but there is a dearth of scientific evidence to support these claims. Compounded BHTs lack well controlled studies examining route of administration, pharmacokinetics, safety, and a critical, science-based rationale for the mixture and ratios of bioidentical estrogens employed in many preparations. Many advocates of compounded BHTs customize prescriptions based on saliva tests or blood sera levels in direct contradiction to evidence-based guidelines, which support tailoring HT individually according to symptoms. Currently, scientific uncertainties associated with compounded BHTs make their use less preferable to that of CHTs, as CHTs have been and continue to be assessed by clinical trials regarding both benefits and risks and are indicated for use according to evidence-based guidelines.