Different cardiovascular effects of progestins according to structure and activity

Effects of biological sex and oral contraception on the sympathetic neurocirculatory adjustments to static handgrip exercise in humans

While biological sex affects the neurocirculatory adjustments to exercise, the effects of sex hormones on sympathetic action potential (AP) patterns and ensuing vascular transduction remain unknown. We tested the hypothesis that males, and females using oral contraceptive pills (OCPs), would demonstrate larger increases in sympathetic activation and sympathetic vascular transduction compared with naturally menstruating females during static handgrip exercise (SHG) and postexercise circulatory occlusion (PECO). Young males [n = 14, 25 (5) yr], females using OCPs [n = 16, 24 (6) yr], and naturally menstruating females [n = 18, 26 (4) yr] underwent assessments of multiunit muscle sympathetic nerve activity (MSNA)/AP discharge patterns (microneurography) and femoral artery blood flow (ultrasound) during fatiguing SHG at 40% maximum voluntary contraction and 2-min PECO. Sympathetic vascular transduction was determined as the quotient of the change in leg vascular conductance (LVC) and MSNA/AP discharge. Males demonstrated greater increases in APs/burst [males: Δ7 (6) vs. midluteal: Δ2 (3), P = 0.028] and total AP clusters [males: Δ5 (3) vs. midluteal: Δ2 (3), P = 0.008] compared with naturally menstruating females only but not those using OCPs during exercise (APs/burst: P = 0.171, total clusters: P = 0.455). Sympathetic vascular transduction of MSNA burst amplitude, APs/burst, and total AP clusters was greater in males and females using OCPs compared with naturally menstruating females (range: P = 0.004-0.044). In contrast, during PECO no group differences were observed in AP discharge (range: P = 0.510-0.872), and AP discharge was not related to LVC during PECO (range: P = 0.08-0.949). These data indicate that biological sex and OCP use impact the central generation of AP discharge, as well as the transduction of these neuronal messages into peripheral vasoconstriction during static exercise.

Understanding Progestins: From Basics to Clinical Applicability

Progestin is a term used to describe a synthetic progestogen. The activity and potency of synthetic progestins are mostly evaluated via parameters associated with their endometrial effects, which are related to their interactions with progesterone, estrogen, androgen, glucocorticoid, and mineralocorticoid receptors. The chemical structure of progestins is the key to understanding their interactions with these receptors and predicting the other effects associated with these drugs. Due to their endometrial effect, progestins are used for different gynecological conditions, such as endometriosis, contraception, hormonal replacement therapy, and artificial reproduction techniques. This review is focused on improving our knowledge of progestins (from their history and biochemical effects related to their chemical structures to clinical applications in gynecological conditions) in order to improve clinical practice.

Oral Contraceptive Pills and Hypertension: A Review of Current Evidence and Recommendations

Oral contraceptive pills (OCPs) have been used as effective and popular forms of contraception since the middle of the last century. By 2019, over 150 million reproductive-aged individuals were using OCPs to prevent unintended pregnancies worldwide. Safety concerns regarding the effects of OCPs on blood pressure were reported soon after these pills gained approval. Although OCP doses were subsequently reduced, epidemiologic evidence continued to support a smaller, but significant association between OCPs and hypertension. Given the rising prevalence of hypertension, as well as the adverse effects of cumulative exposure to blood pressure elevations on cardiovascular disease risk, understanding the nature of the association between OCPs and hypertension is important for clinicians and patients to assess the risks and benefits of use, and make individualized decisions regarding contraception. Therefore, this review summarizes the current and historical evidence describing the association between OCP use and blood pressure elevations. Specifically, it identifies the pathophysiologic mechanisms linking OCPs to hypertension risk, describes the magnitude of the association between OCPs and blood pressure elevations, and distinguishes the effects of various OCP types on blood pressure. Finally, it describes current recommendations regarding hypertension and OCP use, as well as identifies strategies, such as over-the-counter OCP prescribing, to safely and equitably improve access to oral contraception.

The effect of non-oral hormonal contraceptives on hypertension and blood pressure: A systematic review and meta-analysis

Oral contraceptives (OC) are associated with increased risk of hypertension and elevated blood pressure (BP). Whether non-oral hormonal contraceptives have similar associations is unknown. We sought to investigate the effect of non-oral hormonal contraceptive (NOHC) use on the risk of hypertension and changes in BP, compared to non-hormonal contraceptive and OC use. We searched bibliographic databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials) until August 2020. Studies reporting risk of hypertension or changes in systolic and diastolic BP with NOHC use compared with either non-hormonal contraceptive or OC use. Abstract screening, full-text review, data extraction, and quality assessment were completed in duplicate. For studies reporting dichotomous outcomes, we reported results as relative risk with 95% confidence intervals (CI). A random-effects model was used to estimate pooled weighted mean difference and 95% CI of change in BP. Twenty-five studies were included. A lower incidence of hypertension was observed with injectable contraceptive use compared to non-hormonal contraceptive and OC use, although it was unclear if this was statistically significant. Compared to non-hormonal contraceptive use, injectable contraceptive use was associated with increased BP (SBP: 3.24 mmHg, 95%CI 2.49 to 3.98 mmHg; DBP: 3.15 mmHg, 95%CI 0.09 to 6.20 mmHg), the hormonal intra-uterine device use was associated with reduced BP (SBP: -4.50 mmHg, 95%CI -8.44 to -0.57 mmHg; DBP: -7.48 mmHg, 95% -14.90 to -0.05 mmHg), and the vaginal ring was associated with reduced diastolic BP (-3.90 mmHg, 95%CI -6.67 to -1.13 mmHg). Compared to OC use, the injectable contraceptive use was associated with increased diastolic BP (2.38 mmHg, 95%CI 0.39 to 4.38 mmHg). NOHC use is associated with changes in BP which differ by type and route of administration. Given the strong association between incremental increases in BP and cardiovascular risk, prospective studies are required.

Loss of β-Arrestins or six Gα proteins in HEK293 cells caused Warburg effect and prevented progesterone-induced rapid proteasomal degradation of progesterone receptor membrane component 1

Hormonal dysregulation plays a significant role in the metabolic switching during malignant transformation. Progesterone Receptor Membrane Component 1 (PGRMC1) is a single-pass transmembrane receptor activated by the binding of progesterone (P4), a sex hormone. In a previous study, P4 treatment caused rapid (within 30 min) induction of aerobic glycolysis in transformed HEK293 cells, a hallmark malignant phenotype known as the Warburg effect. This metabolic reprogramming was associated with the proteasomal degradation of a 70 kilodalton (kDa) PGRMC1. PGRMC1 interacts with a variety of proteins, including G protein-coupled receptors (GPCRs) and P4-PGRMC1 signaling modulates cyclic adenosine monophosphate (cAMP) production. Therefore, we hypothesized that the P4-induced Warburg effect and proteasomal degradation of PGRMC1 involve G proteins and β-Arrestins (ARRBs). In the present study, we investigated P4-induced aerobic glycolysis, proteasomal degradation of p70 PGRMC1, as well as abundance and subcellular translocation of PGRMC1 along with two key glycolytic enzymes Hexokinase 1 (HK1) and Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) in six Gα subunit (Gsix) proteins or ARRB1/2-deficient HEK293 cells. Loss of ARRB1/2 or Gsix proteins inhibited P4-induced p70 PGRMC1 degradation but failed to prevent the P4-induced Warburg effect. Also, deficiency of ARRB1/2 or Gsix proteins differentially affected the basal as well as P4-induced abundance and subcellular translocation of PGRMC1, HK1, and GAPDH proteins. Overall, the findings indicate that P4-PGRMC1-mediated metabolic reprogramming in HEK293 cells depends on β-Arrestins and Gα proteins suggesting the involvement of an underlying GPCR signal transduction pathway.

Selected Sex Related Differences in Pathophysiology of Cardiovascular System

The annual incidence of cardiovascular diseases is age-dependently increasing both in men and women, however, the prevalence is higher in men until midlife. The higher incidence of cardiovascular disease in men than in women of similar age, and the menopause-associated increase in cardiovascular disease in women, has led to speculation that gender-related differences in sex hormones might have a key role in the development and evolution of cardiovascular disease. There are several suggested pathways in which gender and sex hormones can affect human cardiovascular system to produce original sexually different pathophysiology between women and men. Sex steroid hormones and their receptors are critical determinants of cardiovascular gender differences. Also arterial blood pressure is typically lower in women than in men what could be explained particularly by greater synthesis of nitric oxide (NO) in women. Female cardiomyocytes have a greater survival advantage when challenged with oxidative stress, suggesting that female hormones may play an important role in antioxidative protection of myocardium. It was also demonstrated in animal models that combination of XX chromosomes versus an XY chromosomes enhances sex differences in higher HDL cholesterol. Women were found to have reduced sympathetic activity (reflected by lower total peripheral resistance) and pulmonary artery pressure and enhanced parasympathetic activity relative to men. Similarly, men were found to have higher plasma norepinephrine levels than women. Regarding differences between the sexes in electrophysiology of the heart, two principle mechanisms have been proposed to explain them: hormonal effects on the expression or function of ion channels or, conversely, differences in autonomic tone. To improve diagnosis and treatment of cardiovascular diseases, greater focus on understanding the molecular and cellular physiology of the sex steroid hormones and their receptors in the cardiovascular system will be required.

In vitro effects of progesterone and the synthetic progestin medroxyprogesterone acetate on vascular remodeling

In this work we tested the hypothesis whether progesterone (Pg) or the synthetic progestin medroxyprogesterone acetate (MPA) could be involved in the regulation of events involved in vascular remodeling. Results revealed an enhancement in the capillary-like tubes formation induced by both progestogens. Unlike MPA, Pg acts through VEGF, nitric oxide, PI3K and ERK1/2 signaling pathways. However, the MPA effect depends on platelet activation. Under stress conditions, the proangiogenic action of Pg and MPA was sustained. The progestogens exhibit the ability to prevent vascular smooth muscle cells (VSMC) osteogenic transdifferentiation. Besides this antiosteogenic action, on bone cells the progestogens induced osteoblast maturation and mineralization. The mechanism of action of both steroids on vascular and bone cells involves the participation of progesterone receptor. The data presented in this work provide evidence that the progestogens reduce osteogenic-like transdifferentiation of VSMC and promote angiogenesis with a slight different mechanism of action elicited by each steroid.

The effectiveness of metformin, oral contraceptives, and lifestyle modification in improving the metabolism of overweight women with polycystic ovary syndrome: a network meta-analysis

PURPOSE

We designed a network meta-analysis that investigated relatively different interventions that included the effects of metformin, oral contraceptives, and lifestyle modification on the metabolic parameters of patients with polycystic ovary syndrome. In addition, we searched for eligible interventions that improved the metabolism of glucose and lipids.

METHODS

We searched the PubMed, EMBASE, and Cochrane Central databases from inception to May 2018. Publication types that were categorized as randomized controlled trials met our inclusion criteria. The main outcome included the homeostasis model assessment of insulin resistance, total cholesterol, low-density lipoprotein cholesterol, and total triglycerides. We performed both a pairwise meta-analysis and a network meta-analysis to evaluate the mean difference value and 95% credibility intervals, and we calculated the surface cumulative rank curve.

RESULTS

There were a total of 12 kinds of interventions: metformin, 2 mg cyproterone acetate plus 0.05 mg ethinylestradiol (EE/CA), 0.15 mg desogestrel plus 0.03 mg ethinylestradiol (EE/DSG), and 3 mg drospirenone plus 0.03 mg ethinylestradiol (EE/DRSP), lifestyle, exercise, diet, metformin + lifestyle, metformin + diet, EE/CA + lifestyle, metformin + EE/CA, and EE/DRSP + lifestyle from the 20 eligible RCTs that were included in this study. Our meta-analysis results showed that metformin + lifestyle (MD = -2.04, 95% CrI = -3.64 to -0.41), EE/CA + lifestyle (MD = -2.23, 95% CrI = -4.11 to -0.35), and EE/DRSP + lifestyle (MD = -2.59, 95% CrI = -4.66 to -0.50) resulted in lower in the levels of total cholesterol. Women treated with metformin + lifestyle (MD = -1.82, 95% CrI = -2.88 to -0.79), EE/CA + lifestyle (MD = -2.25, 95% CrI = -3.58 to -1.08), or EE/DRSP + lifestyle (MD = -2.29, 95% CrI = -3.69 to -1.07) exhibited significantly lower low-density lipoprotein cholesterol when compared with the placebo group. There was no significant difference between any of the interventions compared with a placebo in the levels of homeostasis model assessment of insulin resistance and total triglycerides. The surface cumulative rank curve revealed that metformin + lifestyle might be the best intervention with respect to the improvement of the homeostasis model of assessment insulin resistance and EE/DRSP + lifestyle appeared to be the best intervention for the reduction of total cholesterol and low-density lipoprotein cholesterol. Moreover, the metformin + diet intervention was more effective in reducing the level of total triglycerides.

CONCLUSIONS

For overweight polycystic ovary syndrome patients, our evidence revealed that EE/CA and EE/SRSP combined with metformin or lifestyle changes can reduce the adverse effects on glucose and lipid metabolism of the use of oral contraceptive agents alone. Conventional PCOS treatments, such as metformin, EE/CA, and EE/DRSP, combined with lifestyle control can be particularly effective in improving the homeostasis model assessment of insulin resistance and lipid metabolism.

Progesterone induces relaxation of human umbilical cord vascular smooth muscle cells through mPRα (PAQR7)

Progesterone effects on vascular smooth muscle cell (VSMC) relaxation and the mechanism were investigated in cultured human umbilical vein VSMCs. Membrane progesterone receptors mPRα, mPRβ, and mPRγ were highly expressed in VSMCs, whereas nuclear progesterone receptor (nPR) had low expression. Progesterone (20 nM) and 02-0 (mPR-selective agonist), but not R5020 (nPR agonist), induced muscle relaxation in both a VSMC collagen gel disk contraction assay and an endothelium-denuded human umbilical artery ring tension assay. Progesterone and 02-0 increased ERK and Akt phosphorylation and decreased cAMP levels. These effects were blocked by preincubation with pertussis toxin. Progestin-induced muscle relaxation was blocked by pretreatment with mPRα, but not nPR, siRNAs, and by co-treatment with 8-Br-cAMP, AZD6244 (MAP kinase inhibitor), and wortmannin (PI3K inhibitor). Progestins reduced myosin light chain phosphorylation which was blocked with AZD6244 and wortmannin. These results demonstrate progesterone directly relaxes human VSMCs through mPRα/Gi and MAP kinase/ERK-, Akt/PI3K-, and cAMP-dependent pathways.

The effects of progesterones on blood lipids in hormone replacement therapy

The safety of progestogens as a class has drawn much attention after the publication of data from the Women’s Health Initiative (WHI) trial, particularly with respect to cardiovascular disease. Depending on the chemical structure, pharmacokinetics, receptor affinity and potency of action, progestogens have a divergent range of properties that may translate to very different clinical effects. The purpose of this review is to describe the role of varied progestogens in hormone replacement therapy (HRT), especially focusing on blood lipids, which are the most important parameters for assessing cardiovascular disease risk.

Oral Contraceptive Use, Muscle Sympathetic Nerve Activity, and Systemic Hemodynamics in Young Women

Endogenous female sex hormones influence muscle sympathetic nerve activity (MSNA), a regulator of arterial blood pressure and important factor in hypertension development. Although ≈80% of American women report using hormonal contraceptives sometime during their life, the influence of combined oral contraceptives (OCs) on MSNA and systemic hemodynamics remains equivocal. The goal of this study was to determine whether women taking OCs have altered MSNA and hemodynamics (cardiac output and total peripheral resistance) at rest during the placebo phase of OC use compared with women with natural menstrual cycles during the early follicular phase. We retrospectively analyzed data from studies in which healthy, premenopausal women (aged 18-35 years) participated. We collected MSNA values at rest and hemodynamic measurements in women taking OCs (n=53; 25±4 years) and women with natural menstrual cycles (n=74; 25±4 years). Blood pressure was higher in women taking OCs versus those with natural menstrual cycles (mean arterial pressure, 89±1 versus 85±1 mm Hg, respectively; P=0.01), although MSNA was similar in both groups (MSNA burst incidence, 16±1 versus 18±1 bursts/100 heartbeats, respectively; P=0.19). In a subset of women in which detailed hemodynamic data were available, those taking OCs (n=33) had similar cardiac output (4.9±0.2 versus 4.7±0.2 L/min, respectively; P=0.47) and total peripheral resistance (19.2±0.8 versus 20.0±0.9 U, respectively; P=0.51) as women with natural menstrual cycles (n=22). In conclusion, women taking OCs have higher resting blood pressure and similar MSNA and hemodynamics during the placebo phase of OC use when compared with naturally menstruating women in the early follicular phase.

Progesterone increases nitric oxide synthesis in human vascular endothelial cells through activation of membrane progesterone receptor-α

Progesterone exerts beneficial effects on the human cardiovascular system by inducing rapid increases in nitric oxide (NO) production in vascular endothelial cells, but the receptors mediating these nongenomic progesterone actions remain unclear. Using human umbilical vein endothelial cells (HUVECs) as a model, we show that progesterone binds to plasma membranes of HUVECs with the characteristics of membrane progesterone receptors (mPRs). The selective mPR agonist Org OD 02-0 had high binding affinity for the progesterone receptor on HUVEC membranes, whereas nuclear PR (nPR) agonists R5020 and medroxyprogesterone acetate displayed low binding affinities. Immunocytochemical and Western blot analyses confirmed that mPRs are expressed in HUVECs and are localized on their plasma membranes. NO levels increased rapidly after treatment with 20 nM progesterone, Org OD 02-0, and a progesterone-BSA conjugate but not with R5020, suggesting that this progesterone action is at the cell surface and initiated through mPRs. Progesterone and Org OD 02-0 (20 nM) also significantly increased endothelial nitric oxide synthase (eNOS) activity and eNOS phosphorylation. Knockdown of mPRα expression by treatment with small-interfering RNA (siRNA) blocked the stimulatory effects of 20 nM progesterone on NO production and eNOS phosphorylation, whereas knockdown of nPR was ineffective. Treatment with PI3K/Akt and MAP kinase inhibitors blocked the stimulatory effects of progesterone, Org OD 02-0, and progesterone-BSA on NO production and eNOS phosphorylation and also prevented progesterone- and Org OD 02-0-induced increases in Akt and ERK phosphorylation. The results suggest that progesterone stimulation of NO production in HUVECs is mediated by mPRα and involves signaling through PI3K/Akt and MAP kinase pathways.

Effects of a combined oral contraceptive containing 20 mcg of ethinylestradiol and 3 mg of drospirenone on the blood pressure, renin-angiotensin-aldosterone system, insulin resistance, and androgenic profile of healthy young women

Combined oral contraceptives (COCs) may increase the risk for cardiovascular disease depending on the ethynyl estradiol (EE) dose and the androgenicity of the progestogens. Our objective was to evaluate the impact of a COC containing 20 mcg EE + 3 mg drospirenone on blood pressure (BP), renin-angiotensin-aldosterone system, insulin resistance, and androgenic profile of healthy young women. Eighty-one healthy young women aged 30 ± 1 years (case group, n = 49, received COC; control group, n = 32, used no COC) were assessed twice, before and after the 6-month study. Statistical analysis employed the paired t-tests and expressed the data in mean and standard deviation. Results were as follows: no changes in BP or in BMI; a significant increase in aldosterone, plasma renin activity, triglycerides, and total cholesterol levels, but a non-significant increase in HDL and no significant changes in LDL levels (these parameters remained within normal ranges); a significant increase in the HOMA-IR index and a significant decrease in dehydroepiandrosterone sulfate (SDHEA), androstenedione, total testosterone, and free testosterone levels; no significant variations in the control group parameters. An oral contraceptive combination of a low EE dose and an anti-androgenic progestogen does not negatively influence the risk factors for a cardiovascular disease.

Cardiac effects of aldosterone: does gender matter?

Ischemic heart disease (IHD) continues to be the most common cause of death globally, although mortality rates are decreasing with significant advances in treatment. Higher prevalence of co-morbidities in women only partly explains the lack of decrease in mortality rates in younger women due to. Until recently there has been gender bias in pre-clinical studies and many clinical trials, resulting in a significant gap in knowledge whether there are differential responses to therapy for women, particularly younger women. There is increasing evidence that there are significant gender-specific differences in the outcome of post-infarction remodelling, prevalence of hypertension and sudden cardiac death. These differences indicate that cardiac tissue in females displays significant physiological and biochemical differences compared to males. However, the mechanisms mediating these differences, and how they change with age, are poorly understood. Circulating levels and physiological effects of aldosterone vary across the menstrual cycle suggesting female steroid sex hormones may not only regulate production of, but also responses to, aldosterone in pre-menopausal women. This modified tissue response may foster a homeostatic environment where higher levels of aldosterone are tolerated without adverse cardiac effect. Moreover, there is limited data on the direct regulation of this signalling axis by androgens in female animals/subjects. This review explores the relationship between gender and the effects of aldosterone in cardiovascular disease (CVD), an issue of significant need that may lead to changes in best practice to optimise clinical care and improve outcomes for females with CVD.

Progesterone therapy, endothelial function and cardiovascular risk factors: a 3-month randomized, placebo-controlled trial in healthy early postmenopausal women

Background

Progesterone is effective treatment for hot flushes/night sweats. The cardiovascular effects of progesterone therapy are unknown but evidence suggests that premenopausal normal estradiol with also normal progesterone levels may provide later cardiovascular protection. We compared the effects of progesterone to placebo on endothelial function, weight, blood pressure, metabolism, lipids, inflammation and coagulation.

Methods and Results

We conducted a randomized, double-blind, 3-month placebo-controlled trial of progesterone (300 mg daily) among 133 healthy postmenopausal women in Vancouver, Canada from 2003–2009. Endothelial function by venous occlusion plethysmography was a planned primary outcome. Enrolled women were 1–11 y since last menstruation, not using hormones (for >6 months), non-smoking, without diabetes, hypertension, heart disease or their medications. Randomized (1∶1) women (55±4 years, body mass index 25±3) initially had normal blood pressure, fasting lipid, glucose and electrocardiogram results. Endothelial function (% forearm blood flow above saline) was not changed with progesterone (487±189%, n = 18) compared with placebo (408±278%, n = 16) (95% CI diff [−74 to 232], P = 0.30). Progesterone (n = 65) and placebo (n = 47) groups had similar changes in systolic and diastolic blood pressure, resting heart rate, weight, body mass index, waist circumference, total cholesterol, low-density lipoprotein cholesterol and triglyceride levels. High-density lipoprotein was lower (−0.14 mmol/L, P = 0.001) on progesterone compared with placebo. Fasting glucose, hs-C-reactive protein, albumin and D-dimer changes were all comparable to placebo. Framingham General Cardiovascular Risk Profile scores were initially low and remained low with progesterone therapy and not statistically different from placebo.

Conclusions

Results indicate that progesterone has short-term cardiovascular safety. Endothelial function, weight, blood pressure, waist circumference, inflammation and coagulation were unchanged as were lipids except for HDL-C. The statistically significant decrease in HDL-C levels was not clinically important (based on lack of Cardiovascular Risk Profile change).

Trial Registration

ClinicalTrials.gov NCT00152438

Associations between oral contraceptive use and risks of hypertension and prehypertension in a cross-sectional study of Korean women

BACKGROUND

The effect of commonly used oral contraceptives (OCs) on blood pressure is still unclear. The aim of this study was to examine the relationship between OCs use and blood pressure and the prevalence of hypertension in a population-based sample of Korean women.

METHODS

A cross-sectional study was conducted using data from 3356 participants aged 35-55 years collected in the 2007-2009 Korea National Health and Nutrition Examination Surveys. OC use and demographic characteristics were obtained from participants using a questionnaire, and blood pressure was measured with a mercury sphygmomanometer.

RESULTS

Longer duration of OC use was positively associated with increasing levels of systolic blood pressure and diastolic blood pressure (p for trend <0.001). After adjusting for covariates, the odds ratio (OR) of hypertension was significantly increased in longer-term (>24 months) OC users (OR 1.96; 95% confidence interval (CI) 1.03-3.73) compared with those who had never used OCs. Additionally, use of OCs >24 months was associated with increased odds of prehypertension (adjusted OR 2.23; 95% CI 1.28-3.90) and hypertension or prehypertension (adjusted OR 2.13; 95% CI 1.37-3.32).

CONCLUSION

This study found a statistically significant association between OC use and blood pressure or hypertension among Korean women.

Protective actions of progesterone in the cardiovascular system: potential role of membrane progesterone receptors (mPRs) in mediating rapid effects

The protective functions of progesterone in the cardiovascular system have received little attention even though evidence has accumulated that progesterone lowers blood pressure, inhibits coronary hyperactivity and has powerful vasodilatory and natriuretic effects. One possible reason why potential beneficial actions of progesterone on cardiovascular functions have not been extensively studied is that divergent effects to those of progesterone have been observed in many clinical trials with synthetic progestins such as medroxyprogesterone acetate which are associated with increased risk of coronary disease. Evidence that progesterone exerts protective effects on cardiovascular functions is briefly reviewed. The finding that progesterone administration decreases blood vessel vasoconstriction in several animal models within a few minutes suggests that rapid, nongenomic progesterone mechanisms are of physiological importance in regulating vascular tone. Rapid activation of second messenger pathways by progesterone has been observed in vascular endothelial and smooth muscle cells, resulting in alterations in endothelial nitric oxide synthase (eNOS) activity and calcium influx, respectively. Both nuclear progesterone receptors (PRs) and novel membrane progesterone receptors (mPRs) are candidates for the intermediaries in these rapid, cell-surface initiated progesterone actions in endothelial and smooth muscle vascular cells. PRs have been detected in both cell types. New data are presented showing mPRα, mPRβ and mPRγ are also present in human endothelial and smooth muscle vascular cells. Preliminary evidence suggests mPRs mediate rapid progestin signaling in these endothelial cells, resulting in down-regulation of cAMP production and increased nitric oxide synthesis. The role of mPRs in progesterone regulation of cardiovascular functions warrants further investigation.

Postmenopausal hormone therapy: risks and benefits

Postmenopausal hormone therapy (PMHT) is used for the relief of menopausal symptoms, but the dosage has varied greatly throughout its existence. By the end of the 1990s, PMHT was mainly used to prevent chronic diseases such as osteoporosis, coronary heart disease and dementia, and large prevention trials were undertaken in this context. Following the initial negative reports of these trials, use of PMHT dramatically decreased. These reports noted surprisingly increased risks, notably of coronary heart disease, stroke and breast cancer, in people who used PMHT. Nowadays, considering the currently available data, it seems that an important distinction should be made between the treatment of climacteric symptoms in young, generally healthy, postmenopausal women and the prevention of chronic diseases in elderly women. PMHT seems to be beneficial and safe for postmenopausal symptomatic women aged <60 years. Treatments with a high safety profile should be the preferred option, including low-dose PMHT, oestrogen-only therapy in women who have had a hysterectomy, and vaginal oestrogen therapy for women with atrophic vaginitis. Nonandrogenic progestin might have a reduced thrombotic and breast cancer risk, and transdermal oestrogen could have a reduced thrombotic risk. Nevertheless, PMHT should not be used for the prevention of chronic diseases in the elderly (>70 years old) owing to the increased risk of stroke and breast cancer in these patients.

Effects of micronized progesterone added to non-oral estradiol on lipids and cardiovascular risk factors in early postmenopause: a clinical trial

Background

Much attention has been drawn to the deleterious effects of adding progestins to estrogen as hormone therapy (HT) in postmenopausal women. Some widely prescribed progestins have been shown to partially oppose the beneficial effects of estrogens on surrogate markers of cardiovascular disease (CVD) risk. Progestins with higher androgenic activity may interfere with lipid profile and glucose tolerance, and could affect mechanisms of estrogen-induced C-reactive protein (CRP) stimulation. Recent data have shown that norpregnane derivatives, but not micronized progesterone, increase the risk of venous thromboembolism among transdermal estrogens users. The aim of the present study was to assess the effects of combining micronized progesterone with non-oral estrogen therapy on lipid profile and cardiovascular risk factors in a sample of early postmenopausal women.

Methods

Clinical trial including 40 women receiving intranasal 17β estradiol 3 mg/day for two months and 46 women receiving percutaneous 17β estradiol gel 1.5 mg/day for three months (E2). Both groups received an additional 200 mg/day of micronized progesterone by vaginal route 14 days/month (E2+P). Outcome measures included body weight, waist circumference, body mass index (BMI), lipid profile and ultra-sensitive C-reactive protein (usCRP) at baseline and during the E2 or E2+P portions of treatment.

Results

Mean age was 51±3 years. Mean time since menopause was 22.2±10 months. Most participants were overweight; HT did not change BMI. E2 and E2+P did not affect waist circumference and weight. Menopausal symptoms improved after HT. The effects of intranasal and percutaneous estradiol were similar, regardless of the addition of progesterone. Similarly, for the overall group of 86 women, micronized progesterone did not alter the response to E2. Blood pressure, glucose, insulin, HDL-c, triglycerides, and usCRP remained constant with or without micronized progesterone. Total cholesterol decreased after E2, and progesterone maintained this reduction. LDL-c levels were similar at baseline and with E2, and lower during E2+P in relation to baseline.

Conclusions

Cyclic, short term exposure to vaginal micronized progesterone did not alter the metabolic and cardiovascular effects of non-oral E2 in early, apparently healthy, postmenopausal women.

Trial registration

ClinicalTrials.gov NCT01432028

Preclinical pharmacological profile of nomegestrol acetate, a synthetic 19-nor-progesterone derivative

BACKGROUND

Nomegestrol acetate (NOMAC), a synthetic progestogen derived from 19-nor-progesterone, recently completed clinical trials for use with 17beta-estradiol in a new monophasic combined oral contraceptive. In this review, published as well as previously unpublished preclinical studies that detail the effects of NOMAC on estrogenic, progestogenic, and androgenic systems, as well as mineralocorticoid, glucocorticoid, bone, and metabolic indices are described.

METHODS

In vitro assays to determine NOMAC structure-activity relationships used tissue derived from rat uteri. Transactivation profiles were performed using Chinese hamster ovary (CHO) cells transfected with cDNAs encoding human steroid receptors. Estrogenic and anti-estrogenic activities were monitored in vivo in rats as well as in vitro in human breast cancer cells. Standard in vivo techniques were used in rats to determine progestational activity; antigonadotropic, androgenic, mineralocorticoid, and glucocorticoid activities; as well as effects on bone and other metabolic indices. Ovulation inhibition was monitored in rats and primates. NOMAC's effects on cardiovascular systems were determined in dogs and primates.

RESULTS

NOMAC was without significant agonistic or antagonistic activity for estrogen receptor alpha or beta in vitro, and inhibited ovulation in rats and monkeys (2.5 mg/kg and 1 mg/kg, respectively). NOMAC lacked androgenic, antimineralocorticoid, glucocorticoid, and metabolic activity and exhibited moderate anti-androgenic activity in rats. NOMAC did not affect bone mineral density (BMD) in rats or hemodynamic and electrophysiologic parameters in dogs and primates.

CONCLUSIONS

NOMAC is a selective progestogen structurally similar to progesterone that has modest anti-androgenic activity and does not affect lipid or carbohydrate metabolism, BMD, or many cardiovascular parameters in selected animal models.

Metabolic effects of contraceptive steroids

Estrogen and progestins have been used by millions of women as effective combined contraceptives. The safety of hormonal contraceptives has been documented by years of follow-up and serious adverse events that may be related to their use are rare in the young population exposed to these agents. The balance between the benefits and the risks of contraceptive steroids is generally positive in particular when comparing to the risks of pregnancy and especially in women with risk factors. The metabolic changes induced by the synthetic steroids used in contraception, such as lipoprotein changes, insulin response to glucose, and coagulation factors have been considered as potential markers of cardiovascular and venous risk. Observations of these effects have led to modifications of the composition of hormonal contraceptive in order to minimize these changes and hence potentially decrease the risks. The synthetic estrogen Ethinyl-Estradiol (EE) exerts a stronger effect that natural estradiol (E2) on hepatic metabolism including estrogen-dependent markers such as liver proteins. This stronger hepatic impact of EE has been related to its 17α-ethinyl group which prevents the inactivation of the molecule and results in a more pronounced hepatic effect of EE as compared to estradiol. Due to its strong activity, administering EE via a non-oral route does not prevent its impact on liver proteins. In order to circumvent the metabolic changes induced by EE, newer products using more natural compounds such as estradiol (E2) and estradiol valerate (E2V) have been introduced. The synthetic progestins used for contraception are structurally related either to testosterone (T) (estranes and gonanes) or to progesterone (pregnanes and 19-norpregnanes). Several new progestins have been designed to bind more specifically to the progesterone receptor and to minimize side-effects related to androgenic, estrogenic or glucocorticoid receptor interactions. Dienogest (DNG), and drospirenone (DRSP) and the 19-norpregnanes including Nestorone® (NES), nomegestrol acetate (NOMAc) and trimegestone (TMG) have been combined with estrogen either EE or E2 or estradiol valerate (E2V). Risks and benefits of the newer progestins used in contraception depend upon the type of molecular structure, the type and dose of estrogen associated in a combination and the route of administration. The lower metabolic impact of estradiol-based combinations may result in an improved safety profile, but large surveillance studies are warranted to confirm this plausible hypothesis. So far, the contraindications and warnings for use of current COCs also apply to the estradiol-based COCs.

Gender and the renin-angiotensin-aldosterone system

Premenopausal women are protected to some extent from cardiovascular and kidney diseases. Because this protection weakens after menopause, sex hormones are believed to play an important role in the pathogenesis of cardiovascular and kidney diseases. The cardiovascular system and the kidneys are regulated by the renin-angiotensin-aldosterone system (RAAS), which in turn, appears to be regulated by sex hormones. In general, oestrogen increases angiotensinogen levels and decreases renin levels, angiotensin-converting enzyme (ACE) activity, AT(1) receptor density, and aldosterone production. Oestrogen also activates counterparts of the RAAS such as natriuretic peptides, AT(2) receptor density, and angiotensinogen (1-7). Progesterone competes with aldosterone for mineralocorticoid receptor. Less is known about androgens, but testosterone seems to increase renin levels and ACE activity. These effects of sex hormones on the RAAS can explain at least some of the gender differences in cardiovascular and kidney diseases.