Hormone therapy and endometrial angiogenesis

Uterine bleeding with hormone therapies in menopausal women: a systematic review

Uterine bleeding is a common reason why women discontinue menopausal hormone therapy (HT). This systematic review compared bleeding profiles reported in studies for continuous-combined HT approved in North America and Europe for moderate to severe vasomotor symptoms in postmenopausal women with a uterus. Non-head-to-head studies showed that uterine bleeding varies by formulation and administration route, with oral having a better bleeding profile than transdermal formulations. Cumulative amenorrhea over a year ranged from 18 to 61% with oral HT and from 9 to 27% with transdermal HT, as reported for continuous-combined HT containing 17β-estradiol (E2)/progesterone (P4) (56%), E2/norethisterone acetate (NETA) (49%), E2/drospirenone (45%), conjugated equine estrogens/medroxyprogesterone acetate (18-54%), ethinyl estradiol/NETA (31-61%), E2/levonorgestrel patch (16%), and E2/NETA patch (9-27%). Amenorrhea rates and the mean number of bleeding/spotting days improved over time. The oral E2/P4 combination was amongst those with lower bleeding rates and may be an appropriate alternative for millions of women seeking bioidentical HT and/or those who have bleeding concerns with other HT.

Human versus non-human sex steroid use in hormone replacement therapies part 1: Preclinical data

Prior to 2002, hormone replacement therapy (HRT) was considered to be an important component of postmenopausal healthcare. This was based on a plethora of basic, epidemiological and clinical studies demonstrating the health benefits of supplementation with human sex steroids. However, adverse findings from the Women's Health Initiative (WHI) studies that examined the 2 major forms of HRT in use in the US at that time - Premarin (conjugated equine estrogens; CEE) and Prempro (CEE + medroxyprogesterone acetate; MPA), cast a shadow over the use of any form of HRT. Here we review the biochemical and physiological differences between the non-human WHI study hormones - CEE and MPA, and their respective human counterparts 17β-estradiol (E₂) and progesterone (P₄). Preclinical data from the last 30 years demonstrate clear differences between human and non-human sex steroids on numerous molecular, physiological and functional parameters in brain, heart and reproductive tissue. In contrast to CEE supplementation, which is not always detrimental although certainly not as optimal as E₂ supplementation, MPA is clearly not equivalent to P₄, having detrimental effects on cognitive, cardiac and reproductive function. Moreover, unlike P₄, MPA is clearly antagonistic of the positive effects of E₂ and CEE on tissue function. These data indicate that minor chemical changes to human sex steroids result in physiologically distinct actions that are not optimal for tissue health and functioning.

Vaginal bleeding/spotting with conjugated estrogens/bazedoxifene, conjugated estrogens/medroxyprogesterone acetate, and placebo

OBJECTIVE

In the 1-year phase 3 Selective estrogens, Menopause, And Response to Therapy-5 trial, cumulative amenorrhea rates with conjugated estrogens/bazedoxifene (CE/BZA) were similar to placebo and higher than with conjugated estrogens/medroxyprogesterone acetate (CE/MPA). This post hoc analysis reports bleeding/spotting rates in 4-week intervals (cycles) and 3-month intervals (quarters) with these therapies and the percentage of cases attributable to spotting only.

METHODS

Generally healthy postmenopausal women with menopausal symptoms recorded vaginal bleeding/spotting in daily diaries while receiving CE 0.45 mg/BZA 20 mg, CE 0.625 mg/BZA 20 mg, CE 0.45 mg/MPA 1.5 mg, or placebo.

RESULTS

A total of 1596 women in the modified intent-to-treat population contributed data. Incidence of bleeding/spotting was significantly (p < 0.001) lower with CE 0.45 mg/BZA 20 mg (0.54‒4.44%), CE 0.625 mg/BZA 20 mg (1.26‒5.02%), and placebo (1.55‒4.82%) compared with CE 0.45 mg/MPA 1.5 mg (8.81‒25.63%) in all 4-week cycles. Each quarter, <10% of women taking CE/BZA doses or placebo had bleeding/spotting, significantly (p < 0.001) less than the 21-36% with CE 0.45 mg/MPA 1.5 mg. Odds ratio for bleeding/spotting with CE 0.45 mg/BZA 20 mg vs CE 0.45 mg/MPA 1.5 mg was 0.1 in each quarter (95% CI, Q1-Q3: 0.1-0.2; Q4: 0.1-0.3). Across all treatments, most (88-100%) bleeding/spotting cases were spotting only. Mean days of bleeding/spotting were <1 per quarter with CE/BZA doses and placebo, which was significantly (p < 0.01) less than the 3-5 days per quarter with CE/MPA.

CONCLUSIONS

Bleeding/spotting with CE/BZA treatment was similar to placebo and significantly less frequent than with CE/MPA treatment. Most cases were spotting only across all treatments.

Evidence on the use of progesterone in menopausal hormone therapy

A need exists for a regulatory agency-approved hormone therapy (HT) with naturally occurring hormones combining progesterone (P4) and estradiol (E2), since no single product contains both endogenous hormones. Many women choose HT with P4 and millions of women around the world are using unapproved, poorly regulated compounded HT. The use of natural P4 in HT results, for the most part, in favorable outcomes without deleterious effects, as shown in clinical studies of postmenopausal women. Importantly, P4 used in HT prevents endometrial hyperplasia from estrogens while helping relieve vasomotor symptoms and improving quality-of-life measures. Additionally, risk of venous thromboembolism and breast cancer does not appear to increase with use of P4 plus estrogens as shown with synthetic progestins plus estrogens in large observations studies, and no detrimental effects of P4 in HT have been found on outcomes related to cardiovascular disease or cognition. A regulatory agency-approved HT with naturally occurring E2/P4 could be an option for the millions of women who desire a bioidentical product and/or are exposed to potential risks of inadequately studied and under-regulated compounded HT.

Conjugated estrogen/bazedoxifene tablets for the treatment of moderate-to-severe vasomotor symptoms associated with menopause

Conjugated estrogen/bazedoxifene (CE/BZA) therapy represents a new, progestin-free treatment in the management of postmenopausal health. CE/BZA pairs CE with the selective estrogen receptor modulator, BZA. The rationale for the development of CE/BZA was that BZA, acting primarily as a selective estrogen receptor degrader in uterine and breast tissue, would sufficiently inhibit the proliferative effects of CE on the endometrium. The absence of a progestin would reduce the incidence of uterine bleeding, breast pain and increased breast density associated with progestin-containing hormone therapy. CE/BZA has been evaluated in five multicenter, randomized, double-blind, placebo-controlled, and active-controlled Phase III trials known as the SMART trials. CE/BZA has been shown to maintain the established benefits of estrogen therapy for treatment of vasomotor symptoms and prevention of a loss in bone mineral density (bone mass), while minimizing certain estrogenic effects, particularly in the uterine endometrium and breast.

Abnormal bleeding during menopause hormone therapy: insights for clinical management

OBJECTIVE

Our objective was to review the involved mechanisms and propose actions for controlling/treating abnormal uterine bleeding during climacteric hormone therapy.

METHODS

A systemic search of the databases SciELO, MEDLINE, and Pubmed was performed for identifying relevant publications on normal endometrial bleeding, abnormal uterine bleeding, and hormone therapy bleeding.

RESULTS

Before starting hormone therapy, it is essential to exclude any abnormal organic condition, identify women at higher risk for bleeding, and adapt the regimen to suit eachwoman's characteristics. Abnormal bleeding with progesterone/progestogen only, combined sequential, or combined continuous regimens may be corrected by changing the progestogen, adjusting the progestogen or estrogen/progestogen doses, or even switching the initial regimen to other formulation.

CONCLUSION

To diminish the occurrence of abnormal bleeding during hormone therapy (HT), it is important to tailor the regimen to the needs of individual women and identify those with higher risk of bleeding. The use of new agents as adjuvant therapies for decreasing abnormal bleeding in women on HT awaits future studies.

Vascular dysfunction as a cause of endometrial bleeding

INTRODUCTION

Heavy menstrual bleeding (HMB) and the spotting and bleeding (S/B) associated with the use of hormonal contraceptives are distinct entities affecting endometrial vasculature and hemostasis.

MATERIALS AND METHODS

An overview of the major etiologies and potential treatments for each condition is provided.

RESULTS

HMB is potentially caused by several different hemostatic dysfunctions. Combination oral contraceptives, levonorgestrel-releasing intrauterine system, non-steroidal anti-inflammatory drugs, and anti-fibrinolytics all have been shown to have some degree of efficacy in treating HMB. The basic cause of HMB is unknown in the majority of cases. Endometrial S/B related to hormonal contraceptives is a common occurrence and may well have a common etiology in altered angiogenesis resulting in abnormal blood vessels with fragile vessel walls. There is no effective treatment for this problem.

CONCLUSIONS

Medical therapy for HMB is limited and effective for reducing blood loss during menstruation. There is no effective treatment for the S/B associated with hormonal contraceptives.

Hormone replacement therapy and the endometrium

The life-expectancy for women has increased significantly in the 20th century, although the time of onset of menopause has not. Almost a third of a woman's life is now postmenopausal and therefore many postmenopausal women consider using hormone replacement therapy (HRT) to improve their quality of life. Most cases of endometrial carcinoma arise in postmenopausal women and this raises concern among patients and clinicians with regard to the safety of HRT in this age group. Whenever the use of HRT is considered, a careful consideration of the actual benefit in terms of symptom relief and quality of life must be balanced against the risks for each individual woman. This review discusses the effects of HRT on the endometrium and the evidence regarding HRT use and risk of endometrial cancer.

Effects of hormone therapy and dietary soy on myocardial ischemia/reperfusion injury in ovariectomized atherosclerotic monkeys

OBJECTIVE

Hormone therapy (HT) and dietary soy (Soy) inhibit myocardial ischemia/reperfusion (I/R) injury in nonatherosclerotic animals. The aim of this study was to determine their independent and interactive effects on I/R in monkeys previously fed an atherogenic diet for 15 months.

DESIGN

Ovariectomized atherosclerotic monkeys (n = 40) were divided into one of four dietary treatment groups: (1) casein as the protein source, (2) casein and added HT (the equivalent of 5 mug ethinyl estradiol + 1 mg norethindrone acetate daily), (3) Soy protein providing 141 mg total isoflavones daily, or (4) Soy + HT. After 12 months monkeys were anesthetized, and their left anterior descending coronary artery was occluded for 1 hour and reperfused for 4 hours. Infarct size was the percentage of the area at risk not staining with triphenyltetrazolium chloride. Additional measures were myocardial blood flow, stroke volume, coronary output, myeloperoxidase, and malondialdehyde.

RESULTS

There was an interactive negative effect of HT + Soy to increase infarct size from approximately 30% (in other groups) to 55% (P = 0.0004). Additionally, there were negative main effects of Soy on blood flow, coronary output, and stroke volume during I/R (all P values <0.05). There were no effects of treatment on either myeloperoxidase or malondialdehyde.

CONCLUSIONS

Neither HT nor Soy had beneficial effects, whereas their combination had harmful effects, on myocardial I/R injury in monkeys with preexisting atherosclerosis. The mechanism of this negative interaction remains unclear but may relate to Soy's negative effects on hemodynamics.

Effect of hormone replacement therapy on postmenopausal endometrial bleeding

The aim of the study was to determine the effect of postmenopausal hormone replacement therapy (HRT) (treatment using estrogen only and sequential and continuous combined estrogen-progestogen treatment) on endometrial bleeding and histological changes of the endometrium. In a six-year period (2000-2005), 5893 patients were given care and the incidence of postmenopausal uterine bleeding was detected in groups of patients having and not having received hormonal treatment at the Menopause Outpatient Unit of the authors' department. In the case of bleeding, fractioned abrasion was performed and the samples were analyzed histologically. Among the postmenopausal patients who had not been given hormonal treatment, the incidence of bleeding episodes was significantly higher as among those having received hormonal treatment. In the samples, findings of proliferative endometrium occurred significantly more often in case of non-treated patients and those treated with sequential combined hormone therapy compared to patients receiving continuous combined hormone therapy. Although it was statistically not significant, hyperplasia simplex and complex together showed a tendency of reduced incidence in patients medicated by continuous combined treatment. These findings suggest that continuous combined hormonal treatment started at the right time (even before the menopause) may reduce the chances of the development of hyperplasia. A significantly higher incidence of hyperplasia was noted in patients using estrogen treatment only. It is possible that unopposed estrogen treatment further engraves an already diagnosed endometrial hyperplasia. In the group having received hormonal treatment, no complex hyperplasia accompanied by atypia occurred, only hyperplasia simplex was diagnosed in these cases. As a result of continuous reliance on combined preparations, the endometrium had become atrophied, therefore the chance of hyperplasia-related changes and of bleeding as a side effect decreased significantly. According to the authors' experience, hormonal treatment does not pose a risk to the development of endometrial carcinoma; on the contrary, continuous combined preparations appear to reduce the risk of hyperplasia and, indirectly, the chances of the development of adenocarcinoma.

Long-term use of progestogens--getting the balance right: molecular biology and the endometrium

The role of progestins in long-term treatment has recently been under scrutiny, in particular as their effects on organs other than the endometrium, such as the breast or the cardiovascular system, could give rise to undesirable reactions. The use of progestins in hormone replacement therapy has highlighted the importance of choice of progestin. Insights into the molecular biology of normal processes in the endometrium can help to find accurate markers for progestin effects and help select progestins with a better benefit-risk profile. Such insight can also lead to a better understanding of the etiology of menstrual and fertility disorders and ultimately to new therapeutic approaches.

Anti-angiogenic effects of imatinib target smooth muscle cells but not endothelial cells

Knowing that progesterone up-regulates PDGF-A, which plays a relevant role in angiogenesis, and that imatinib mesylate targets PDGF receptor tyrosine kinase activity, the aim of the present study was to examine the effects of imatinib on Human Aortic Smooth Muscle Cells (HAoSMC) and Human Umbilical Vein Endothelial Cells (HUVEC) after incubation with progesterone. Expression of phosphorylated (activated) PDGFR-alpha was detected in HAoSMC, but in a very low extent in HUVEC. In agreement with the lack of active PDGFR-alpha, imatinib was unable to prevent HUVEC growth, survival or migration ability. In contrast, HAoSMC viability and proliferation were effectively inhibited by imatinib, as evaluated by MTT and BrdU incorporation assay, respectively. Corroborating these findings, a significant increase in the percentage of apoptotic cells was also observed after treatment with imatinib. Cell migration assays also showed a reduction in the migratory ability after incubation with imatinib. Altogether, these facts reveal that imatinib is able to affect HAoSMC survival, growth and migration. Furthermore, incubation with recombinant PDGF as well as, with progesterone seems to sustain PDGFR-alpha activity, prompting these cells to the inhibitory action of imatinib. These findings were restricted to smooth muscle cells, leading to the assumption that imatinib is probably preventing vessel stabilization, a crucial event for neovascular maturation. Our findings indicate that imatinib might be a good therapeutic agent against atherosclerosis and other vascular-associated disorders that carry in common smooth muscle cells abnormal growth.

The effect of postmenopausal hormone replacement therapy on endometrial bleeding

Cékitűzés: A vizsgálat célja meghatározni a postmenopausalis hormonterápia (kizárólagos ösztrogén-, szekvenciális és folyamatosan kombinált ösztrogén-progesztogén kezelés) hatását az endometrialis vérzésre és a méhnyálkahártya szövettani átalakulására. Beteganyag: Szerzők klinikájának Menopauza Ambulanciáján ötéves időszakban (2000–2005) 5893 beteget gondoztak, és vizsgálták a postmenopausalis méhvérzések előfordulását a hormonterápiában részesültek és nem részesültek csoportjában. Vérzés esetén mindig frakcionált abrasiót végeztek, és a mintákat szövettanilag feldolgozták. Eredmények: A postmenopausában lévő betegek hormonkezelésben nem részesítettek csoportjában több mint kétszer több vérzés fordult elő, mint a hormonkezelésben részesültek között. Anyagukban a proliferatiós és a hyperplasiás endometrium-leletek elsősorban a nem kezelt páciensek közül kerültek ki, ami amellett szól, hogy a megfelelő időben, akár már a menopausa előtt megkezdett hormonkezelés csökkentheti a hyperplasia és ezáltal közvetve az adenocarcinoma kialakulásának az esélyét. A kizárólag ösztrogént alkalmazó betegekben gyakoribb volt a hyperplasia. Elképzelhetőnek tartják, hogy az ellensúlyozatlan ösztrogénkezelés a már meglévő endometrium-hyperplasiát tovább súlyosbíthatja. A hormonkezeltek csoportjában atípiával járó komplex hyperplasia nem, csak simplex hyperplasia fordult elő. A folyamatosan kombinált készítmények alkalmazása mellett az esetek döntő részében a méhnyálkahártya atrófizálódott, így lényegesen csökkent a hyperplasiával járó eltérések s a mellékhatásként jelentkező vérzés esélye. A hormonkezeltek között gyakoribb volt az endometrium-polip, és nem tudják megmagyarázni, de a cervicalis polypusok aránya is. Következtetés: A szerzők tapasztalata szerint a hormonkezelés nem rizikótényezője az endometrium-karcinómának, hanem a kombinált készítmények a hyperplasia és ezen keresztül az adenocarcinoma eredeti esélyét csökkentik.

Endometrial bleeding during hormone therapy: The effect of progestogens

Postmenopausal women using continuous combined estrogen/progestin therapy (ccEPT) are likely to have irregular bleeding or spotting. The use of estrogen with 12-14 days of a progestin is called cyclic (scEPT). This method results in regular endometrial bleeding at a scheduled time. The mechanism(s) involved in this regimen that result in bleeding could be similar to a spontaneous menstrual bleeding episode in a menachal woman, but there are no data in this regard. This aspect of regular scheduled bleeding in postmenopausal women will not be addressed in this article due to the paucity of information. The effect of cyclic progestogen with continuous estrogen on the endometrium could result in similar local mechanisms for endometrial bleeding as seen wth ccEPT. The mechanism(s) involved in endometrial bleeding is unknown. Several reports have highlighted a number of potential pathophysiologic mechanisms. Most of the investigation into the mechanisms involved in endometrial bleeding has been in women using progestin only contraceptive methods not ccEPT. The use of ccEPT could be construed as similar but not identical to that of a continuous progestin only contraceptive since the progestin in ccEPT is delivered daily. The potential mechanism(s) involved in endometrial bleeding includes the following: changes in the ratio of vascular endothelial growth factor to Thrombospondin-1 (pro- versus anti-angiogenic factors); alterations in metalloproteinases and tissue inhibitor of metalloproteinases (TIMP); changes in tissue factor a known haemostasis mediator in the endometrium; and increased endometrial leukocytes with a particular emphasis on uterine natural killer (uNK) cells. Each of these potential causes has been the subject of both in vivo and in vitro investigations. There is no clear linkage between any of these hypotheses and the onset or cessation of uterine bleeding in ccEPT users. No good therapeutic option to control the bleeding or spotting exists at this time. Evaluation and monitoring of the patient regarding endometrial safety is of paramount importance.

Elucidating progesterone effects in breast cancer: Cross talk with PDGF signaling pathway in smooth muscle cell

Several studies indicate that progesterone exerts relevant effects in breast tissue. However, the exact role of this steroid in breast cancer development and progression has not been elucidated. Here, we show that platelet-derived growth factor (PDGF)-A is one of the progesterone target genes on breast cancer MCF7 and T47D cells. A paracrine role for PDGF-A was investigated, since its receptor expression was down-regulated from breast cancer cells. Progesterone increased PDGF-A protein release as evaluated by Western blotting and ELISA. Medium from Progesterone-treated MCF7 cells resulted in phosphorylation of smooth muscle cells PDGF receptor alpha. This effect was not observed after treatment with PDGF inhibitor. MCF7 cells-secreted PDGF-A was able to increase smooth muscle cell viability and proliferation and decrease apoptosis, effects that were prevented by the use of a PDGF-A neutralizing antibody. Notably, cell invasion was not influenced by PDGF-A secreted by MCF7 cells. Our results elucidated for the first time the cross talk between progesterone and PDGF signaling pathway. The fact that MCF7-secreted PDGF elicited crucial roles in vascular wall smooth muscle cells, suggested a paracrine pathway for progesterone. Targeting these progesterone-induced processes may provide novel therapeutic strategies for hormone-dependent human breast cancer.

A 5-year study on the effect of hormone therapy, tibolone and raloxifene on vaginal bleeding and endometrial thickness

OBJECTIVES

To study the effect of standard and low-dose estrogen-progestin therapy (EPT), tibolone and raloxifene on the incidence of vaginal spotting/bleeding and endometrial thickness over a 5-year period.

METHODS

Seven hundred eighty-six postmenopausal women were studied in an open prospective design. Vaginal spotting/bleeding and endometrial thickness as assessed by transvaginal ultrasonography was compared between six categories of women over a 5-year period: three categories in women on continuous combined estrogen-progestin therapy, one category under tibolone, one category under raloxifene and one under no treatment. More specifically, women received tibolone 2.5 mg (N = 204), raloxifene HCl 60 mg (N = 137), conjugated equine estrogens 0.625 mg/medroxyprogesterone acetate 5mg (N = 122), 17beta-estradiol 2mg/norethisterone acetate 1mg (N = 58), 17beta-estradiol 1mg/norethisterone acetate 0.5mg (N = 76) or no therapy (controls, N = 189). Women with suspected endometrial pathology were referred for hysteroscopy.

RESULTS

Bleeding/spotting incidence was highest among standard dose EPT users (conjugated equine estrogens 0.625 mg/medroxyprogesterone acetate 5mg: 40.1%, 17beta-estradiol 2mg/norethisterone acetate 1mg: 44.8%, p < 0.001 compared to controls). Low-dose EPT associated with lower incidence of spotting/bleeding (34.1%). The incidence under tibolone and raloxifene was 22.5% and 2.9%, respectively, while 3.2% of women not receiving therapy reported vaginal spotting/bleeding. Mean endometrial thickness was not significantly affected in any of the groups studied. The drop-out rate due to spotting/bleeding was higher in the two higher dose EPT regimens. After logistic regression analysis, age at baseline was the only significant predictor of subsequent spotting/bleeding (b = -0.25, S.E. = 0.09, p = 0.006), while menopausal age and pre-treatment serum FSH had marginal significance.

CONCLUSIONS

EPT, tibolone and raloxifene do not appear to associate with significant changes in endometrial thickness in the majority of cases. The low-dose EPT regimen associated with a decreased incidence of unscheduled spotting/bleeding compared to the standard dose regimens. Tibolone expressed a favorable endometrial profile, as seen in its effect on unscheduled spotting/bleeding and mean endometrial thickness. Raloxifene associated with the lowest incidence in S/B and the lowest drop-out rate.s.

Progestogen only contraception and endometrial break through bleeding

Progestogen only contraceptives (POC) provide a safe and effective method of fertility regulation. Unfortunately, they are commonly associated with the problem of endometrial break through bleeding (BTB), often leading to discontinuation of use. An increase in endometrial vascular fragility has been demonstrated as an important mechanism that contributes to BTB but our understanding of the interaction between exogenous steroid use and endometrial vasculature remains incomplete. This review sets out to describe a number of commonly used POC, their effects on endometrial morphology and possible molecular and cellular mechanisms that may lead to unscheduled bleeding.