Effects of estradiol with micronized progesterone or medroxyprogesterone acetate on risk markers for breast cancer in postmenopausal monkeys

Menopausal Hormone Therapy Formulation and Breast Cancer Risk

OBJECTIVE

To evaluate whether the increased risk of breast cancer is dependent on the formulation of menopausal hormone therapy (HT) used.

METHODS

We performed a population-based case-control study of women aged 50 years or older using data from the U.K. Clinical Practice Research Datalink. Women with incident cases of breast cancer were age-matched (1:10) with a control group of women with comparable follow-up time with no history of breast cancer. Exposures were classified as ever or never for the following menopausal HT formulations: bioidentical estrogens, animal-derived estrogens, micronized progesterone, and synthetic progestin. Logistic regression analyses were performed to estimate the adjusted effect of menopausal HT formulation on breast cancer risk.

RESULTS

Between 1995 and 2014, 43,183 cases of breast cancer were identified and matched to 431,830 women in a control group. In adjusted analyses, compared with women who never used menopausal HT, its use was associated with an increased risk of breast cancer (odds ratio [OR] 1.12, 95% CI 1.09-1.15). Compared with never users, estrogens were not associated with breast cancer (bioidentical estrogens: OR 1.04, 95% CI 1.00-1.09; animal-derived estrogens: OR 1.01, 95% CI 0.96-1.06; both: OR 0.96, 95% CI 0.89-1.03). Progestogens appeared to be differentially associated with breast cancer (micronized progesterone: OR 0.99, 95% CI 0.55-1.79; synthetic progestin: OR 1.28, 95% CI 1.22-1.35; both OR 1.31, 0.30-5.73).

CONCLUSION

Although menopausal HT use appears to be associated with an overall increased risk of breast cancer, this risk appears predominantly mediated through formulations containing synthetic progestins. When prescribing menopausal HT, micronized progesterone may be the safer progestogen to be used.

Hormone Therapy in Menopause: Concepts, Controversies, and Approach to Treatment

Hormone therapy (HT) is an effective treatment for menopausal symptoms, including vasomotor symptoms and genitourinary syndrome of menopause. Randomized trials also demonstrate positive effects on bone health, and age-stratified analyses indicate more favorable effects on coronary heart disease and all-cause mortality in younger women (close proximity to menopause) than in women more than a decade past menopause. In the absence of contraindications or other major comorbidities, recently menopausal women with moderate or severe symptoms are appropriate candidates for HT. The Women's Health Initiative (WHI) hormone therapy trials-estrogen and progestin trial and the estrogen-alone trial-clarified the benefits and risks of HT, including how the results differed by age. A key lesson from the WHI trials, which was unfortunately lost in the posttrial cacophony, was that the risk:benefit ratio and safety profile of HT differed markedly by clinical characteristics of the participants, especially age, time since menopause, and comorbidity status. In the present review of the WHI and other recent HT trials, we aim to provide readers with an improved understanding of the importance of the timing of HT initiation, type and route of administration, and of patient-specific considerations that should be weighed when prescribing HT.

Progesterone suppresses the progression of colonic carcinoma by increasing the activity of the GADD45α/JNK/c‑Jun signalling pathway

Colorectal cancer (CRC) is the third most diagnosed cancer worldwide. Progesterone is associated with a decreased risk of CRC and leads to a favourable prognosis. However, the specific mechanism by which progesterone suppresses malignant progression remains to be elucidated. In the present study, the level of progesterone was first analysed in 77 patients with CRC, and immunohistochemistry was performed to detect the expression of progesterone receptor (PGR) in the paired specimens. The correlations between progesterone, PGR and CRC prognosis were assessed. A Cell Counting Kit-8 assay was then used to detect proliferation of the CRC cells. Flow cytometry was performed to estimate apoptosis and to evaluate the cycle of the CRC cells. A xenograft tumour model was established in nude mice to assess the role of progesterone in tumour growth. Finally, a PCR microarray was used to screen differentially expressed genes to further interpret the mechanism by which progesterone inhibits the malignant progression of CRC. It was found that low expression of progesterone and PGR were significantly associated with poor prognosis of CRC. In addition, progesterone suppressed CRC cell proliferation by arresting the cell cycle and inducing apoptosis in vitro. Moreover, the inhibitory role of progesterone in tumour growth was verified in vivo. Further investigation showed that the level of growth arrest and DNA damage-inducible protein α (GADD45α) was up-regulated by progesterone, and this was followed by the activation of the JNK pathway. Progesterone increased the activity of the JNK pathway via GADD45α to inhibit proliferation by arresting the cell cycle and inducing apoptosis, thereby suppressing the malignant progression of CRC. Therefore, it can be concluded that progesterone and PGR might act as inhibiting factors for poor prognosis of CRC.

Hormone replacement therapy - where are we now?

Hormone replacement therapy (HRT) was the standard of care for menopause management until 2002, when perceptions changed following release of the initial results from the Women's Health Initiative (WHI) trial. Fears of breast cancer and heart attacks engendered by that report were not supported by the data, especially for recently menopausal women. Clinically, HRT is usually initiated near menopause. The WHI tested something different - the effects of HRT started a decade or more after menopause. As it turned out, age at starting HRT is critical in determining benefit/risk. HRT use plummeted following the WHI in 2002 and has remained low, prompting strong interest in alternative treatments. None provide the range of benefits across multiple organ systems offered by estrogen. Most have concerning adverse effects in their own right. HRT can provide effective relief for a wide range of health conditions, potentially avoiding the need for multiple treatments for separate problems. Unfortunately, among many women and clinicians, the perception of HRT benefit/risk is distorted, and its use avoided, leading to unnecessary distress. Following the WHI, many clinicians have not received adequate training to feel comfortable prescribing HRT. When initiated within 10 years of menopause, HRT reduces all-cause mortality and risks of coronary disease, osteoporosis, and dementias.

Nonhuman primate model in mammary gland biology and neoplasia research

Research on breast cancer pathogenesis, prevention and drug development remains an important field as this disease is still one of the leading causes of cancer death worldwide. Nonhuman primates, particularly macaque species, may serve as a highly translational animal model in breast cancer studies due to their similarity with humans in genetics, anatomy, reproductive and endocrine physiology including mammary gland development profile. The use of nonhuman primates in biomedical research, however, requires high ethical standards and an increasing expectation to improve strategies to replace, reduce and refine their use. Here, we discuss some key features of nonhuman primate mammary gland biology relevant to their strengths and limitations as models in studies of breast development and cancer risk.

Contrasting effects of Western vs Mediterranean diets on monocyte inflammatory gene expression and social behavior in a primate model

Dietary changes associated with industrialization increase the prevalence of chronic diseases, such as obesity, type II diabetes, and cardiovascular disease. This relationship is often attributed to an 'evolutionary mismatch' between human physiology and modern nutritional environments. Western diets enriched with foods that were scarce throughout human evolutionary history (e.g. simple sugars and saturated fats) promote inflammation and disease relative to diets more akin to ancestral human hunter-gatherer diets, such as a Mediterranean diet. Peripheral blood monocytes, precursors to macrophages and important mediators of innate immunity and inflammation, are sensitive to the environment and may represent a critical intermediate in the pathway linking diet to disease. We evaluated the effects of 15 months of whole diet manipulations mimicking Western or Mediterranean diet patterns on monocyte polarization in a well-established model of human health, the cynomolgus macaque (Macaca fascicularis). Monocyte transcriptional profiles differed markedly between diets, with 40% of transcripts showing differential expression (FDR < 0.05). Monocytes from Western diet consumers were polarized toward a more proinflammatory phenotype. The Western diet shifted the co-expression of 445 gene pairs, including small RNAs and transcription factors associated with metabolism and adiposity in humans, and dramatically altered behavior. For example, Western-fed individuals were more anxious and less socially integrated. These behavioral changes were also associated with some of the effects of diet on gene expression, suggesting an interaction between diet, central nervous system activity, and monocyte gene expression. This study provides new molecular insights into an evolutionary mismatch and uncovers new pathways through which Western diets alter monocyte polarization toward a proinflammatory phenotype.

The Effect of Perimenopausal Transdermal Estradiol and Micronized Progesterone on Markers of Risk for Arterial Disease

BACKGROUND

The arterial effects of hormone therapy remain controversial. This study tested the effects of transdermal estradiol plus intermittent micronized progesterone (TE + IMP) in healthy perimenopausal and early postmenopausal women on several mechanisms involved in the pathophysiology of arterial disease.

METHODS

Healthy perimenopausal and early postmenopausal women, ages 45 to 60 years, were enrolled in this randomized, double-blind, placebo-controlled trial. Women were randomized to receive TE (0.1 mg/day) + IMP (200 mg/day for 12 days) or identical placebo patches and pills for 12 months. Outcomes included: change in stress reactivity composite z-score (combining inflammatory, cortisol, and hemodynamic responses to a standardized psychological laboratory stressor); flow-mediated dilation (FMD) of the brachial artery (an index of vascular endothelial function); baroreflex sensitivity; and metabolic risk (presence of the metabolic syndrome or insulin resistance), all assessed at baseline and at months 6 and 12.

RESULTS

Of 172 women enrolled, those assigned to TE + IMP tended to have higher resting baroreflex sensitivity than those assigned to placebo across the 6- and 12-month visits. Although treatment groups did not differ in terms of the other prespecified outcomes, a significant treatment-by-age interaction was found for FMD and stress reactivity such that an age-related decrease in FMD and increase in stress reactivity were seen among women assigned to placebo but not those assigned to TE + IMP. Women on TE + IMP also had lower resting diastolic blood pressure, lower levels of low-density lipoprotein cholesterol, and higher baroreflex sensitivity during stress testing.

CONCLUSIONS

TE + IMP tended to improve cardiac autonomic control and prevented age-related changes in stress reactivity and endothelial function among healthy perimenopausal and early postmenopausal women.

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.

Consumption of Mediterranean versus Western Diet Leads to Distinct Mammary Gland Microbiome Populations

Recent identification of a mammary gland-specific microbiome led to studies investigating bacteria populations in breast cancer. Malignant breast tumors have lower Lactobacillus abundance compared with benign lesions, implicating Lactobacillus as a negative regulator of breast cancer. Diet is a main determinant of gut microbial diversity. Whether diet affects breast microbiome populations is unknown. In a non-human primate model, we found that consumption of a Western or Mediterranean diet modulated mammary gland microbiota and metabolite profiles. Mediterranean diet consumption led to increased mammary gland Lactobacillus abundance compared with Western diet-fed monkeys. Moreover, mammary glands from Mediterranean diet-fed monkeys had higher levels of bile acid metabolites and increased bacterial-processed bioactive compounds. These data suggest that diet directly influences microbiome populations outside the intestinal tract in distal sites such as the mammary gland. Our study demonstrates that diet affects the mammary gland microbiome, establishing an alternative mechanistic pathway for breast cancer prevention.

The Impact of Hormonal Contraceptives on Breast Cancer Pathology

This retrospective case series study, using data obtained through questionnaires and histopathological diagnoses from 656 patients enrolled in the Department of Defense (DoD) Clinical Breast Care Project (CBCP), evaluated associations between hormonal contraceptive use and breast cancer pathology including benign breast pathologies. Three combination hormonal contraceptive agents (COCs) Lo Ovral (LO), Ortho Novum (ON), and Ortho Tri-Cyclen (OTC) were evaluated as they represented the most commonly used hormonal contraceptives in our cohort. The results of this study suggest that the ever use of LO + ON + OTC does not influence the overall incidence of benign breast condition or malignant disease compared to other COCs; however, patients that have used OTC had an association with a diagnosis of benign or luminal A pathologies whereas ON was associated with a diagnosis of benign and DCIS; LO showed no association with any diagnosis-benign or malignant. Patients that have used LO or ON were more likely to be diagnosed with breast cancer at age ≥ 40 years whereas patients that had ever used OTC were likely to be diagnosed before the age of 40. Caucasians were less likely to have used OTC and more likely to have used ON; however, use of either hormonal agent positively correlated with premenopausal status at diagnosis and having a benign condition. Age at diagnosis, ethnicity, BMI, family history, menstruation status, and duration of use were all independent predictors of different histopathological subtypes. We conclude that patient-specific variables should be considered when deciding on which type of hormonal contraceptive to use to minimize the risk of developing breast cancer or a breast-related pathology.

The impact of micronized progesterone on breast cancer risk: a systematic review

Postmenopausal women with an intact uterus using estrogen therapy should receive a progestogen for endometrial protection. The debate on bioidentical hormones including micronized progesterone has increased in recent years. Based on a systematic literature review on the impact of menopausal hormone therapy (MHT) containing micronized progesterone on the mammary gland, an international expert panel's recommendations are as follows: (1) estrogens combined with oral (approved) or vaginal (off-label use) micronized progesterone do not increase breast cancer risk for up to 5 years of treatment duration; (2) there is limited evidence that estrogens combined with oral micronized progesterone applied for more than 5 years are associated with an increased breast cancer risk; and (3) counseling on combined MHT should cover breast cancer risk - regardless of the progestogen chosen. Yet, women should also be counseled on other modifiable and non-modifiable breast cancer risk factors in order to balance the impact of combined MHT on the breast.

Estrogen Effects on the Mammary Gland in Early and Late Life and Breast Cancer Risk

A woman has an increased risk of breast cancer if her lifelong estrogen exposure is increased due to an early menarche, a late menopause, and/or an absence of childbearing. For decades, it was presumed that the number of years of exposure drove the increased risk, however, recent epidemiological data have shown that early life exposure (young menarche) has a more significant effect on cancer risk than late menopause. Thus, rather than the overall exposure it seems that the timing of hormone exposure plays a major role in defining breast cancer risk. In support of this, it is also known that aberrant hormonal exposure prior to puberty can also increase breast cancer risk, yet the elevated estrogen levels during pregnancy decrease breast cancer risk. This suggests that the effects of estrogen on the mammary gland/breast are age-dependent. In this review article, we will discuss the existing epidemiological data linking hormone exposure and estrogen receptor-positive breast cancer risk including menarche, menopause, parity, and aberrant environmental hormone exposure. We will discuss the predominantly rodent generated experimental data that confirm the association with hormone exposure and breast cancer risk, confirming its use as a model system. We will review the work that has been done attempting to define the direct effects of estrogen on the breast, which are beginning to reveal the mechanism of increased cancer risk. We will then conclude with our views on the most pertinent questions to be addressed experimentally in order to explore the relationship between age, estrogen exposure, and breast cancer risk.

Deciphering the divergent roles of progestogens in breast cancer

Most breast cancers are driven by oestrogen receptor-α. Anti-oestrogenic drugs are the standard treatment for these breast cancers; however, treatment resistance is common, necessitating new therapeutic strategies. Recent preclinical and historical clinical studies support the use of progestogens to activate the progesterone receptor (PR) in breast cancers. However, widespread controversy exists regarding the role of progestogens in this disease, hindering the clinical implementation of PR-targeted therapies. Herein, we present and discuss data at the root of this controversy and clarify the confusion and misinterpretations that have consequently arisen. We then present our view on how progestogens may be safely and effectively used in treating breast cancer.

Effects of Pubertal Exposure to Dietary Soy on Estrogen Receptor Activity in the Breast of Cynomolgus Macaques

Endogenous estrogens influence mammary gland development during puberty and breast cancer risk during adulthood. Early-life exposure to dietary or environmental estrogens may alter estrogen-mediated processes. Soy foods contain phytoestrogenic isoflavones (IF), which have mixed estrogen agonist/antagonist properties. Here, we evaluated mammary gland responses over time in pubertal female cynomolgus macaques fed diets containing either casein/lactalbumin (n = 12) or soy protein containing a human-equivalent dose of 120 mg IF/day (n = 17) for approximately 4.5 years spanning menarche. We assessed estrogen receptor (ER) expression and activity, promoter methylation of ERs and their downstream targets, and markers of estrogen metabolism. Expression of ERα and classical ERα response genes (TFF1, PGR, and GREB1) decreased with maturity, independent of diet. A significant inverse correlation was observed between TFF1 mRNA and methylation of CpG sites within the TFF1 promoter. Soy effects included lower ERβ expression before menarche and lower mRNA for ERα and GREB1 after menarche. Expression of GATA-3, an epithelial differentiation marker that regulates ERα-mediated transcription, was elevated before menarche and decreased after menarche in soy-fed animals. Soy did not significantly alter expression of other ER activity markers, estrogen-metabolizing enzymes, or promoter methylation for ERs or ER-regulated genes. Our results demonstrate greater ER expression and activity during the pubertal transition, supporting the idea that this life stage is a critical window for phenotypic modulation by estrogenic compounds. Pubertal soy exposure decreases mammary ERα expression after menarche and exerts subtle effects on receptor activity and mammary gland differentiation. Cancer Prev Res; 9(5); 385-95. ©2016 AACR.

Reprint of "Use of medroxyprogesterone acetate for hormone therapy in postmenopausal women: Is it safe?"

Medroxyprogesterone acetate (MPA) has been in clinical use for over 30 years, and was generally considered to be safe until the results of long-term studies of postmenopausal hormone therapy (HT) using treatment with conjugated equine estrogens (CEE) combined with MPA and CEE alone suggested that MPA, and perhaps other progestogens, may play a role in the increased risk of breast cancer and cardiovascular diseases. This review examines critically the safety of MPA in terms of breast cancer and cardiovascular disease risk, and its effects on brain function. Research into mechanisms by which MPA might cause adverse effects in these areas, combined with the available clinical evidence, suggests a small increase in relative risk for breast cancer and stroke, and a decline in cognitive function, in older women using MPA with an estrogen for postmenopausal HT. However, short-term (less than 5 years) use of MPA with an estrogen in the years immediately after the onset of menopause for the management of vasomotor symptoms does not appear to be associated with any increased risk of these disorders.

The Effect of Menopausal Hormone Therapies on Breast Cancer: Avoiding the Risk

Estrogen and P treatment results in greater risk of breast cancer than placebo. Treatment with estrogen alone does not increase the risk of breast cancer, may be used by women who have had a hysterectomy, and may even result in a decreased risk of breast cancer. Continued research seeks to improve the understanding of the interplay between estrogen and progestogens that predispose to adverse effects on breast tissue. Caution over this hypothesized benefit is warranted until it is substantiated by data on the incidence of breast cancer in tissue selective estrogen complex users.

Sex hormone replacement in ovarian failure - new treatment concepts

Premature ovarian failure is associated with decreased bone mass and fractures, and an increased risk of premature death from cardiovascular disease. There is also fertility compromise associated not only with the loss of ovarian function but, in those with pre-pubertal POF, inadequate uterine morphology. A wide variety of hormone replacement regimes are reported, but there is no clear evidence of best practice. Hormone replacement therapy (HRT) and the combined oral contraceptive pill (COCP) will suppress menopausal symptoms; however neither is designed to achieve physiological replacement of oestrogen and progesterone. There is evidence that physiological sex steroid replacement is superior to standard hormone replacement, in improving uterine volume as well as an improved blood pressure profile and bone mineral density. Sex steroid replacement therapy is long-term in these women, and therefore it is essential that the risk benefit ratio is optimal to maximise longer term health.

Is breast cancer risk the same for all progestogens?

The population-based case–control study CECILE investigated the impact of various menopausal hormone therapy (MHT) products on breast cancer (BC) risk in 1,555 postmenopausal women [1]. The case group (n = 739) included incident cases of in situ (!) or invasive BC in postmenopausal women. The control group (n = 816) included women from the general population within predefined quotas by age and socio-economic status (SES). While quotas by age were applied to obtain similar distributions by age among controls and among cases, quotas by SES in control women were applied to reflect the distribution by SES of women in the general population in the study area. Data of participants were obtained by a structured questionnaire during in-person interviews, and from pathology reports if applicable, respectively. Women were divided into current and past MHT user. MHTs were classified in estrogen-only therapy (ET), estrogen combined with progestin therapy (EPT) and tibolone. EPT was subdivided in three subtypes according to the progestogen constituent: natural micronized progesterone, progesterone derivatives, and testosterone derivatives. In comparison to never MHT users, any current or past MHT use (ET, EPT, tibolone) was not associated with an increased BC risk. However, in subanalysis BC risk was significantly increased for current use of EPT for 4 or more years (n = 73 cases and n = 56 controls, adjusted OR 1.55; 95 % CI 1.02–2.36). Within the group of current EPT users for 4 or more years, 14 cases had used estrogens combined with micronized progesterone (n = 17 controls), and 55 a combination with a synthetic progestogen (n = 34 controls), respectively. Compared to never MHT use, current use of EPT containing a synthetic progestogen for 4 or more years was associated with a significantly increased BC risk (adjusted OR 2.07; 95 % CI 1.26–3.39), but EPT containing micronized progesterone was not (adjusted OR 0.79; 95 % CI 0.37–1.71). 73 % of current MHT users started treatment within the first year of onset of menopause. Early EPT (n = 52 cases and n = 38 controls, adjusted OR 1.65; 95 % CI 1.02–2.69), but not early ET, starters had a significantly higher BC risk compared to never MHT users. In contrast, MHT initiation beyond 1 year after menopause was not associated with an increased BC risk. The authors concluded that: (1) ET and EPT containing natural progesterone did not increase BC risk whereas, (2) BC risk was increased in users of tibolone or EPT containing a synthetic progestogen, respectively, and that (3) MHT use early after onset of menopause was associated with an increased BC risk as compared to women who delay MHT beyond 1 or more years.

Use of medroxyprogesterone acetate for hormone therapy in postmenopausal women: is it safe?

Medroxyprogesterone acetate (MPA) has been in clinical use for over 30 years, and was generally considered to be safe until the results of long-term studies of postmenopausal hormone therapy (HT) using treatment with conjugated equine estrogens (CEE) combined with MPA and CEE alone suggested that MPA, and perhaps other progestogens, may play a role in the increased risk of breast cancer and cardiovascular diseases. This review examines critically the safety of MPA in terms of breast cancer and cardiovascular disease risk, and its effects on brain function. Research into mechanisms by which MPA might cause adverse effects in these areas, combined with the available clinical evidence, suggests a small increase in relative risk for breast cancer and stroke, and a decline in cognitive function, in older women using MPA with an estrogen for postmenopausal HT. However, short-term (less than 5 years) use of MPA with an estrogen in the years immediately after the onset of menopause for the management of vasomotor symptoms does not appear to be associated with any increased risk of these disorders.

HRT: some unresolved clinical issues in breast cancer, endometrial cancer and premature ovarian insufficiency

Many important issues regarding HRT and the management of postmenopausal women are unresolved and require ongoing consideration and some explanation. HRT is only one of many factors affecting the risk of breast cancer and the risk of breast cancer is not increased in past users of HRT. There is seemingly a paradox in the effect of body weight and HRT on breast cancer risk. It is unclear whether the benefit of giving progestin with estrogen to prevent endometrial cancer in HRT outweighs the increased risk of breast cancer. Sequential HRT may not fully prevent endometrial cancer, and continuous combined regimes are to be preferred. The prevention of the consequences of premature ovarian insuffiency, both immediate and long term, has been neglected, and a strong case can be made for estrogen replacement therapy in all women with premature ovarian insuffiency, particularly following bilateral oophorectomy.

Progesterone--promoter or inhibitor of breast cancer

Based on the results of a French cohort of postmenopausal women, it has been claimed that micronized progesterone does not enhance breast cancer risk. The impact of reproductive factors on breast cancer risk and a high prevalence of occult breast carcinomas at the time of menopause suggest an involvement of endogenous progesterone in the development of breast cancer. High mammographic density in the luteal phase and during treatment with estrogen/progestogen combinations reflect a change in the composition of mammary stroma and an increased water accumulation in the extracellular matrix which is caused by hygroscopic hyaluronan-proteoglycan aggregates. Proteoglycans are also involved in the regulation of proliferation, migration, and differentiation of epithelial cells and angiogenesis, and may influence malignant transformation of breast cells and progression of tumors. Reports on a lack of effect of estrogen/progesterone therapy on breast cancer risk may be rooted in a selective prescription to overweight women and/or to the very low progesterone serum levels after oral administration owing to a strong inactivation rate. The contradictory results concerning the proliferative effect of progesterone may be associated with a different local metabolism in normal compared to malignant breast tissue. Similar to other progestogens, hormone replacement therapy with progesterone seems to promote the development of breast cancer, provided that the progesterone serum levels have reached the threshold for endometrial protection.

Progesterone for hot flush and night sweat treatment--effectiveness for severe vasomotor symptoms and lack of withdrawal rebound

A controlled trial recently showed that oral micronized progesterone (Progesterone, 300 mg at h.s. daily) was effective for vasomotor symptoms (VMS) in 133 healthy early postmenopausal women. Here, we present subgroup data in women with severe VMS (50 VMS of moderate-severe intensity/wk) and also 1-mo withdrawal study outcomes. Women with severe VMS (n = 46) resembled the full cohort but experienced 10 VMS/d of 3 of 4 intensity. On therapy, the progesterone VMS number (#) decreased significantly more than placebo # to 5.5/day (d) versus 8/d (ANCOVA -2.0 95% CI: -3.5 to -0.4). Just after trial mid-point, a withdrawal substudy (D/C) was added--56 women were invited and 34 (61%) took part (progesterone 17; placebo 17). Those in the D/C cohort resembled the whole cohort. On stopping, VMS gradually increased--at D/C week 4, on progesterone, VMS daily # reached 78% and significantly less than baseline (-3.0 to -0.8) but placebo VMS # did not differ from run-in. In summary, progesterone is effective for severe VMS and does not cause a rebound increase in VMS when stopped. That progesterone may be used alone for severe VMS and unlike estrogen does not appear to cause a withdrawal rebound increases VMS treatment options.

Percutaneous estradiol/oral micronized progesterone has less-adverse effects and different gene regulations than oral conjugated equine estrogens/medroxyprogesterone acetate in the breasts of healthy women in vivo

Gene expression analysis of healthy postmenopausal women in a prospective clinical study indicated that genes encoding for epithelial proliferation markers Ki-67 and progesterone receptor B mRNA are differentially expressed in women using hormone therapy (HT) with natural versus synthetic estrogens. Two 28-day cycles of daily estradiol (E2) gel 1.5 mg and oral micronized progesterone (P) 200 mg/day for the last 14 days of each cycle did not significantly increase breast epithelial proliferation (Ki-67 MIB-1 positive cells) at the cell level nor at the mRNA level (MKI-67 gene). A borderline significant beneficial reduction in anti-apoptotic protein bcl-2, favouring apoptosis, was also seen followed by a slight numeric decrease of its mRNA. By contrast, two 28-day cycles of daily oral conjugated equine estrogens (CEE) 0.625 mg and oral medroxyprogesterone acetate (MPA) 5 mg for the last 14 days of each cycle significantly increased proliferation at both the cell level and at the mRNA level, and significantly enhanced mammographic breast density, an important risk factor for breast cancer. In addition, CEE/MPA affected around 2,500 genes compared with just 600 affected by E2/P. These results suggest that HT with natural estrogens affects a much smaller number of genes and has less-adverse effects on the normal breast in vivo than conventional, synthetic therapy.

Controlled-release vaginal ring drug-delivery systems: a key strategy for the development of effective HIV microbicides

BACKGROUND

Over half of all HIV-infected adults are women and heterosexual intercourse is a significant mode of viral transmission. This review examines the potential for using polymeric vaginal ring systems to provide controlled delivery of HIV microbicides in order to prevent heterosexual transmission of the virus.

DISCUSSION

Continuous delivery of microbicides has the potential to be more effective than one-off dosing. Thus, controlled-release vaginal delivery devices are now a key area of HIV prevention research. Initial clinical trials on vaginal rings loaded with dapivirine (a candidate microbicide) have indicated that these products are safe and well tolerated by women. These devices are female-initiated, robust and capable of long-term delivery of the active agent.

CONCLUSIONS

Vaginal rings may offer an effective system for the controlled delivery of microbicides to prevent heterosexual transmission of HIV. Candidate vaginal ring microbicide products are now in clinical trials.

Ulipristal acetate does not impact human normal breast tissue

BACKGROUND

Antiprogestins are of growing interest for the development of new treatments in the gynecological field. Ulipristal acetate (UPA) is a progesterone receptor (PR) modulator considered for long-term administration in contraception and is currently being registered for the treatment of uterine fibroids. In light of the influences of hormonal dysfunction in breast pathologies, the secondary consequences of chronic UPA therapy need to be established. The aim of this study was to determine UPA actions mediated by PR and glucocorticoid receptor (GR) in normal and transformed breast.

METHODS

UPA, progesterone (P) and dexamethasone (DEX) effects were observed on PR and GR responsive genes and on proliferation and apoptosis of normal human breast epithelial (HBE) and breast cancer cells. Human normal breast tissue samples were xenografted in athymic mice and treated with estradiol (E2), or E2 + P, or E2 + P + UPA.

RESULTS

Analysis of PR and GR reporter gene transactivation and their respective endogenous target genes indicated that UPA exerted anti-progestational and anti-glucocorticoid activity in both types of cells with a more pronounced effect in cancer cells. When combined with P or DEX, UPA limits the proliferation of HBE cells but increases growth in breast cancer cell lines. UPA administration had no impact on the mitotic index on xenografted human breast tissue exposed to gonadal hormones at similar concentrations to those present in normal women.

CONCLUSIONS

Although further clinical trials are required to confirm that the results from our experimental models can be extrapolated to women treated with UPA, they suggest that such treatment would not be deleterious to normal breast tissue at least for a cycle (28 days) of continuous administration.

Changing concepts: Menopausal hormone therapy and breast cancer

Hormone therapy is still used by millions of women for menopausal symptoms. Concerns regarding hormone therapy and breast cancer were initially based on case reports and retrospective case-control studies. However, recent results from large prospective cohort studies and the Women's Health Initiative (WHI) randomized placebo-controlled hormone therapy trials have substantially changed concepts regarding how estrogen alone and estrogen plus progestin influence breast cancer. The preponderance of observational studies suggested that estrogen alone and estrogen plus progestin both increased the risk of breast cancer, with cancers commonly diagnosed at an early stage. However, substantially different results emerged from the WHI randomized hormone therapy trials. In the WHI trial evaluating estrogen plus progestin in postmenopausal women with an intact uterus, combined hormone therapy statistically significantly increased the risk of breast cancer and hindered breast cancer detection, leading to delayed diagnosis and a statistically significant increase in breast cancer mortality. By contrast, estrogen alone use by postmenopausal women with prior hysterectomy in the WHI trial did not substantially interfere with breast cancer detection and statistically significantly decreased the risk of breast cancer. Differential mammography usage patterns may explain differences between observational study and randomized trial results. In clinical practice, hormone therapy users have mammograms more frequently than nonusers, leading to more and earlier stage cancer detection. By contrast, in the WHI randomized trials, mammogram frequency was protocol mandated and balanced between comparison groups. Currently, the different effects of estrogen plus progestin vs estrogen alone on breast cancer are not completely understood.

Hormone replacement therapy in the geriatric patient: current state of the evidence and questions for the future. Estrogen, progesterone, testosterone, and thyroid hormone augmentation in geriatric clinical practice: part 1

This article presents an up-to-date review of the literature on hormone augmentation in the elderly to help primary care physicians better evaluate and utilize hormone replacement and optimization strategies to benefit their patients. The scientific literature suggests that hormone supplementation with estrogen, progesterone, testosterone, growth hormone, and thyroid hormone has the potential to improve quality of life and to prevent, or reverse, the many symptoms and conditions associated with aging, including fatigue, depression, weight gain,frailty, osteoporosis, loss of libido, and heart disease. Possible long-term side effects are also considered.

Glucocorticoid receptor and breast cancer

Stress enhances glucocorticoid (GC) synthesis, which alters inflammation and immune responses, as well as cellular proliferation and apoptosis in a number of tissues. Increasingly, stress has been associated with cancer progression, and in particular in breast cancer. Consequently, an operational glucocorticoid receptor system in breast tissue influences breast cancer development. In this review, we summarize the data on the GC/GR system in normal and tumoral breast tissue. We also review the molecular mechanisms by which GCs control apoptosis and proliferation in breast cancer models and how GCs alter the chemotherapy of breast cancer treatment when used in combination. Finally, we discuss the participation of GR in breast tumorigenesis under hormone replacement therapy.

A novel regimen of combination transdermal estrogen and intermittent vaginally administered progesterone for relief of menopausal symptoms

OBJECTIVES

To determine the safety and efficacy of a novel regimen of transdermal estrogen and vaginally administered progesterone for treatment of menopausal symptoms.

STUDY METHODS

A retrospective chart review was conducted of menopausal patients aged 46-65, using an oestradiol patch and vaginally administered prometrium for at least 1 year. Available transvaginal ultrasound (TVUS) measurements of endometrial thickness and endometrial biopsy results after at least 1 year of treatment were collated. Symptom relief, bleeding and side effects were reviewed.

RESULTS

Forty-one patients were identified, using an estrogen patch ranging from 25 to 100 μg twice weekly and vaginal prometrium either continuously 3-5 days weekly (36 patients), or sequentially 12 days/month (5 patients). Seventeen patients were lost to follow-up or discontinued therapy within 1 year. Only 23.5% (4/17 patients) of patients who had a TVUS after 1 year (or sooner if bleeding occurred) had a thickened endometrial lining on ultrasound (>5 mm), and all of these had normal endometrial biopsies. By 1 year of follow-up, 91.7% of patients were amenorrhoeic. All patients had relief of menopausal symptoms.

CONCLUSIONS

Vaginal administration of progesterone as part of combined estrogen plus progestin therapy has the potential for decreasing side effects while maintaining endometrial safety and amenorrhoea. Larger prospective trials are warranted.

Progestagen component in combined hormone replacement therapy in postmenopausal women and breast cancer risk: a debated clinical issue

The relevance of the progestagen component in combined hormone replacement therapy (HRT) for breast cancer risk has been long debated. In vitro studies have shown that progestins exert both genomic transcriptional and non-genomic effects that can enhance the proliferation, invasiveness and spread of breast cancer cells. According to a novel hypothesis, progestins can still activate cancer stem cells in patients with pre-existing, clinically undetected breast cancer. However, some experimental and clinical data suggest that different progestins may have a different impact on the pathophysiology of malignant breast cells. In vitro studies on estrogen receptor (ER)+ breast cancer cells have shown that the addition of medroxyprogesterone acetate (MPA) to estradiol (E(2)) produces a significantly higher increase of the mRNA levels and activities of estrogen-activating enzymes aromatase, 17beta hydroxysteroid dehydrogenase type-1 and sulfatase when compared with progesterone plus E(2). In randomised trial performed on ovariectomised adult female monkeys, oral E(2) plus MPA have resulted in a significantly greater proliferation of breast lobular and ductal epithelium when compared with placebo, whereas E(2) plus micronised progesterone have not. In the same experimental model, oral E(2) plus MPA have been found to induce the expression of genes encoding epidermal growth factor receptor (EGFR) ligands and downstream targets, whereas E(2) alone or E(2) plus micronised progesterone had no or modest effects on EGFR-related genes. In last years, some clinical studies on HRT users have shown that androgenic progestin- or MPA-based formulations are associated with an increased breast cancer incidence, whereas micronised progesterone- or dydrogesterone-based formulations are not. Further basic and clinical investigations on this topic are strongly warranted to elucidate whether the choice of the progestagen component in combined HRT could be of clinical relevance as for breast cancer risk.

New hormonal therapies and regimens in the postmenopause: routes of administration and timing of initiation

Since the publication of the Women's Health Initiative (WHI) study followed by the results of the Million Women Study (MWS), the role of hormonal therapy in postmenopausal women has been further challenged. The risks attributed to hormone therapy have been overestimated and the data has been wrongly extrapolated to the whole class of therapies. The trends in postmenopausal hormonal therapy seem now to favor the non-oral delivery routes for both the estrogen and the progestin for women with an intact uterus, based on the assumption that a lesser stimulation of the liver proteins and a neutral metabolic profile would be more favorable in terms of cardiovascular and venous risk. The combination of non-oral administration of estradiol and local delivery of progesterone or a progestin such as levonorgestrel by means of gels, sprays, vaginal rings or intrauterine systems would represent new methods of replacement therapy for the menopausal woman, improving compliance and minimizing the risks of hormone replacement. Several of these systems are either available or in development. Long-term studies on the risk/benefit of various non-oral formulations are certainly warranted.

Mammary gland and endometrial effects of testosterone in combination with oral estradiol and progesterone

OBJECTIVE

The goal of this pilot study was to evaluate the effects of testosterone (T) cotherapy on mammary gland and endometrial measures in a postmenopausal primate model.

METHODS

Twenty-five surgically postmenopausal cynomolgus monkeys were randomized by social group to receive daily treatment with (1) placebo, (2) oral micronized 17beta-estradiol (1 mg/d equivalent in women) + progesterone (200 mg/d equivalent in women) (E + P), or (3) E + P with T administered via subcutaneous pellets for 8 weeks at a high dose (15 mg) followed by 8 weeks at a low dose (1.5 mg) (E + P + T). The main outcome measures were breast and endometrial epithelial proliferation, as measured by Ki67/MIB1 immunolabeling.

RESULTS

Intralobular breast proliferation did not differ significantly among groups after 8 weeks of treatment but was marginally higher (P = 0.03) in the E + P + T group after 16 weeks of treatment. No significant increase in proliferation was seen for E + P alone. Comparable changes in mammary gland markers of estrogen-receptor activity were seen for the E + P and E + P + T groups. In the endometrium, the addition of T did not increase endometrial glandular proliferation or estrogen-receptor activity or result in any distinct histologic changes.

CONCLUSIONS

The findings of this study do not support the idea that T antagonizes the effects of combined hormone therapy on breast proliferation or markers of estrogen-receptor activity. Overall, the short-term effects of T cotherapy on the mammary gland and endometrium were minimal.

Progesterone and medroxyprogesterone acetate differentially regulate alpha4 subunit expression of GABA(A) receptors in the CA1 hippocampus of female rats

The Women's Health Initiative trials - in which more extreme adverse outcomes were observed in the medroxyprogesterone acetate (MPA) + conjugated equine estrogen (CEE) arm, as compared to the CEE only arm - suggest that the addition of MPA to estrogen treatment has undesirable consequences. An important question raised by these results is whether the adverse outcomes observed in the progestin arm can be attributed to effects that are unique to MPA or are common to all progestins. In this study we explored the potential for MPA and progesterone (P4) to differentially impact neuroendocrine function by comparing their effects on mRNA expression for the alpha4 subunit of GABA(a) receptors in the CA1 hippocampus of female rats. Prior research has shown that P4, acting through its reduced metabolite allopregnanolone (AP), can mediate alpha4 subunit expression, thereby altering GABA(A) receptor gated currents. By contrast, MPA competitively inhibits the enzymes necessary for the synthesis of AP. In this study, ovariectomized females were primed with estradiol benzoate and then treated with P4, MPA, or vehicle. Subjects were sacrificed 12 h or 24 h later and in situ hybridization was used to measure alpha4 mRNA in the CA1 hippocampus. At 12 h but not 24 h, alpha4 mRNA was reduced in the P4 group as compared to the MPA group, and as compared to the vehicle group. These results suggest that MPA, while progestational in terms of its effects in the uterus, is not a simple substitute for P4 in other systems. The relative impact of these two progestins on neuroendocrine function must be carefully explored.

The Mammary Glands of Macaques

This review describes the normal biology and physiology of the mammary gland in macaques, including the typical histologic appearance across the life span (development, reproductive maturity, lactation, and senescence). The molecular events regulating breast morphogenesis are described, as well as systemic and local hormonal regulators of mammary gland proliferation, differentiation, and function. Similarities and differences to the human breast are described. Regulatory events are illuminated by discussion of genetically modified mouse models. Tissue response markers, including immunohistochemical markers of proliferation and other hormonally induced changes and studies to date, regarding the effects of exogenous hormones, are briefly summarized. In general, estrogens stimulate progesterone receptor expression and proliferation in the mammary gland, and combinations of estrogens and progestogens cause greater proliferation than estrogens alone. Evaluation of novel chemical agents in macaques requires careful evaluation of age and hormonal context to avoid the confounding effects of mammary gland development, past reproductive history, and other influences on mammary gland morphology. The expression of proliferation markers and progesterone receptors may be used as biomarkers to measure chemically induced hormonal effects.